Title of Invention	AN IMPROVED DEVICE FOR LEATHER PROCESSING
Abstract	An improved device for leather processing comprising a cylindrical vessel (27) encasing more than one perforated longitudinal compartments (41) characterized in that the said encasing fitted with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis, out of which at least one of them being openably fixed by conventional means (29) such as herein described, the said caps (31) being provided with co-centric inlets (46) and bottom draining outlets (45), the said caps being connected internally by perforated dummy disc door (42) having leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture (43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands (28) being provided on the side with supporting roller assembly (40) for preventing slippage during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of the vessel (27) in upward as well as downward directions, the said entire unit along with accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn connected to another power transmission source (37) so as to provide a combination of rotary as well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom with a conventional source for air pressure generation (47), air chamber (48), valves (49), air lifters (50), and chemical container (51) all connected by known conventional means such as herein described and forming a self generating pneumatic system for continuous addition of chemicals during processing, through the cap inlet (46), the entire said assembly being held by bearings supported rotatable main shaft (32) fixed onto main frame assembly (30).

Title of Invention

AN IMPROVED DEVICE FOR LEATHER PROCESSING

Abstract

An improved device for leather processing comprising a cylindrical vessel (27) encasing more than one perforated longitudinal compartments (41) characterized in that the said encasing fitted with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis, out of which at least one of them being openably fixed by conventional means (29) such as herein described, the said caps (31) being provided with co-centric inlets (46) and bottom draining outlets (45), the said caps being connected internally by perforated dummy disc door (42) having leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture (43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands (28) being provided on the side with supporting roller assembly (40) for preventing slippage during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of the vessel (27) in upward as well as downward directions, the said entire unit along with accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn connected to another power transmission source (37) so as to provide a combination of rotary as well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom with a conventional source for air pressure generation (47), air chamber (48), valves (49), air lifters (50), and chemical container (51) all connected by known conventional means such as herein described and forming a self generating pneumatic system for continuous addition of chemicals during processing, through the cap inlet (46), the entire said assembly being held by bearings supported rotatable main shaft (32) fixed onto main frame assembly (30).

Full Text	The present invention relates to an improved device for leather processing. The device of the present invention has potential application in pre-tanning, tanning and post tanning wet operations in leather processing industry. The wet processing of hides and skins are conventionally done in pit, vat, paddle and wooden drum. While using pit and vat, the hides/skins are put into the process liquor and handled manually. It has prompted -the tanners to use paddle to impart the agitation in the liquor by rotation of the blades of the paddle using motor and gearbox, thereby providing mechanical agitation to the stock to be processed. Much better effect of the desired mechanical action under dynamic condition on the hide/skin to be processed is however provided in a tanning drum, which has been in use since 1903. Rotational movement of the drum ensures that the skins/hides are first lifted up by the shelves or pegs and then allowed to fall down under gravity to the processing liquor, resulting in considerable mechanical action. As re'ported by Sharphouse (Leather Technician's Hand book -- year 1S71, Appendix 7 Pages 543 to 547 published by Leather producer's association) and K.T. Sarkar author and publisher (Theory and practice of leather manufactures -5th edition, year 1997- pages 732-761) this conventional drumming is associated with the following limitations. a) It involves the possibility of damage of the sides/skins under processing, by scrapping, scuffing, knotting, shape distortion, wrinkling, grain pebbling, loosening of fiber structure or loss in area. b) It is associated with difficulty in thorough cleaning of the stock, which lets out lot of water adding to the effluent disposal problem. c) It involves the inconvenience in opening the drum for unloading and other intermittent checking. d) Since the float of the drum cannot go beyond the axle level, the capacity utilization is very low to the tune of only 35% of the volume of the drum. e) Moreover, the turbulence generated in a tanning bath due to the rotational movement of the device results not only in reduced diffusion of chemicals, but also in enhanced friction among the surfaces of the skins/hides, thereby contributing to the degradation of the quality of the final leather. g) To process in short float as a measure against effluent problems, which requires strengthening of drum drives, a higher motor power is required for safe and efficient running. h) Normally, the required starting torque, which plays an important role in the selection of motor for any application, is very high to the tune of 3 times of the running torque due to the following reasons. 1 .concentrated load of the hide/skin 2.Self-weight of the wooden tanning drum, 3.Friction because of the journal bearings and 4.The possible spur gear errors. It is thus obvious that the motors used for running the drums are usually oversized to take care of starting torque, resulting in poor efficiency under normal running condition. The above limitations have prompted the researchers to explore better options for leather processing device. Tombetti et al (Abstract published in Journal of American Leather Chemists Association, 75, 62, 1980) developed a pressure vessel for leather tanning, a assembly of which is shown in fig. 1 of the drawings accompanying this specification. The pressure vessel comprises, a rotating inner drum (2) divided into three perforated compartments, each having a door (6), housed in a stationary exterior casing (1) provided with a door (7) and an inlet for chemical and water housed on a frame assembly (3), the said inner drum (2) being rotated with the help of main shaft (4), held by two bearings and housing (5) and connected to a power transmission assembly source (8), the pressure inside the inner drum (2) being generated with the help of a pneumatic system (9). It has been possible to enhance the capacity utilization to about 60% due to the provision of plurality of compartments provided in the pressure vessel. Moreover, the distribution of load, while the vessel is in motion ensures that the starting torque required for running the device is around 2 times of the running torque, thereby suggesting economy in energy consumption. Nevertheless, the pressure vessel is also associated with the following limitations. Association of moving parts with the inner vessel, which is connected to a rotating main shaft, has greater implication of wear and tear, that is likely to result in leakage of air, thereby causing loss of pressure inside the vessel. The stationary outer shell does not provide any option for automatic unloading of the leathers, which have to be taken out manually, thereby implying more labor as well as time. Our copending Indian patent application No. 791/DEL/2000 as shown in fig. 2,3 & 4 of the drawings, has been an,attempt towards obviating the aforesaid limitations by way of providing an improved tanning device comprising a perforated inner vessel (15) having shelves more than one (17) and a door (16). The said inner vessel (15) being housed on non-corrosive chemical resistant rollers (18) fixed on the inner wall of the outer vessel (22) made up of a non-corrosive material capable of withstanding pressure of minimum 5 Kg/cm2, and the said outer vessel (22) being provided with a leak-proof packing (21) and dome shaped caps (20) on either side, the said outer shell being provided with inlet for chemicals and water (23), conventional regulated temperature device (24), discharge for liquid (26), a pressure nozzle (25) connected to a compressor and regulator externally (not shown in the drawing) for developing air pressure inside the vessel. The entire oscillating exterior shell (10) along with all accessories defined herein before being placed on center shaft (not shown in the drawing) being attached to the frame assembly (11). A conventional rocking mechanism (13) being provided on the outer shell and-connected to the normal power transmission assembly (12) in turn connected to the mechanism for rotating action (14) thereby ensuring rocking action as well as rotational movement of the inner perforated vessel (15) with the help of non corrosive chemical resistance gear (19) fixed on the outside of the inner vessel (15). The main advantages of this device over the known pressure vessel are the following. 1.Unlike the known pressure vessel, where only rotary motion is possible, this device provides option for both oscillatory as well as rotary motion. 2.The outer shell of the device undergoes rocking action, which enables an operator to adjust it in a convenient position so as to unload the processed stock by gravity automatically, thereby not only doing away with the extra labor associated with unloading, but also in reducing unloading tiine. 3.Since the inner vessel is rotated by the rollers fixed to the inside of the. outer shell of the device, no leakage of internal pressure is envisaged and at the same time long life is ensured for the device. 4.Unlike the existing systems, the starting torque of the device is only about 1.5 times of the running torque as against much higher values for the existing devices, thereby reducing the power requirement considerably. 5..Capacity utilization of the device is around 70% as against 45% in the existing wooden drum. 6.Even without opening the vessel door, the critical parameters like pH, temperature of the float can be measured only by opening the outlet. However, the device is still constrained by the following limitations. The device provides a two-vessel system having an outer casing as well as an inner vessel, thereby escalating not oniy the fabrication complexities, but also cost. An external energy source is required in the form of an air compressor to form a pneumatic system, thereby adding to cost. The device does not provide, like the conventional tanning drums, any option for automatic mixing of chemicals inside the-drum, thereby implying the requirement of proper mixing of chemicals. The main objective of the present invention is to provide an improved device for leather processing, which obviates the drawbacks stated above. Another objective of the present invention is to provide a single vessel system exhibiting both oscillatory as well as rotary motions like upward and downward directions with less noise. Yet another objective of the present invention is to provide a leather-tanning device to employ pressure technique and at the same time to maintain the internal pressure while processing leathers. Still another objective of the present invention is to provide a device exhibiting provision for automatic unloading of the processed stock. Another objective of the present invention is to increase the capacity utilization of the vessel to more than 75%. Still another objective of the present invention is to ensure that the power consumption and the processing time are reduced as compared to those in the similar oper=ations in respect of the devices known in the existing art. Yet another objective of the present invention is to provide a device to process in short float as a measure against effluent problems by consuming lesser energy compared to the conventional tanning drum. Still another objective of the present invention is to provide a device exhibiting provision for the chemical addition manually or mechanically. The present invention provides an improved device for leather processing comprising a vessel containing perforated dummy doors and compartments with pegs as well as friction disk fixed along the exterior periphery of the vessel. The leathers to be wet processed-are subjected to mechanical action in terms of both rocking action as well as rotational movement simultaneously. The perpetual motion of the device helps to create pressure generation for quickening the process and for addition of chemical solution continuously. The processing takes place under pressure generated inside the vessel and with the support of multiple mechanical actions, resulting in higher exhaustion of bath with less processing time and energy requirement and higher capacity utilization to produce good quality leather. In the drawings accompanying this specification : Fig 1 represents the assembly of the existing pressure drum. Fig. 2 represents the assembly and parts of the improved tanning device (ITD), as described in our co pending patent application no. 791 DEL 2000 Fig. 3 represents the parts of the inner vessel of the ITD Fig 4. represents the parts of the shell of the ITD Fig 5. represents the assembly and parts of the Improved Device for Leather Processing (IDLP) of the present invention. Fig 6. represents the parts and pictorial view of the rotating & oscillation mechanisms of the Improved Device for Leather Processing (IDLP) of the present invention. Fig 7. represents the pictorial view and parts of the vessel of the IDLP of the present invention. FigSr represents the assembly and parts of the pneumatic system of the IDLP of the present invention. Different parts of Fig. 1 showing assembly of the existing pressure drum are as follows: 1. refers to the-stationary exterior casing 2. refers to the perforated inner rotating drum 3. refers to the frame assembly 4. refers to the center shaft 5. refers to the bearings and housings 6. refers to the perforated three compartments with each one door. 7. refers to the door to the exterior casing. 8. refers to the power transmission source. 9. refers to the inlet for chemical and water and with pneumatic system. Different parts of Fig. 2 showing assembly of the improved tanning device (791/Del/2000) are as follows: 10. refers to the oscillating exterior shell. 11. refers to the frame assembly. 12. refers to the power transmission assembly. 13. refers to the mechanism for rocking action of the device 14. refers to the mechanism for rotating action of the device Different parts of Fig. 3 showing details of inner vessel of the ITD (791/Del/2000) are as follows: 15. refers to the perforated inner vessel 16. refers to doors of the inner vessel 17. refers to the shelves/ compartments inside the inner vessel 18. refers to the rollers fixed on the inner side of the outer vessel 19. refers to the pinion & gear fixed on the outer side of the inner vessel Different parts of Fig 4 showing details of shell of the ITD (791/Del/2000) are as follows: 20. refers to the dome shaped caps 21. refers to the leak proof packing 22. refers to the outer vessel 23. refers to the inlet for chemical and water 24. refers to the conventional regulated temperature device 25. refers to the nozzle connected with pressure regulator and compressor 26. refer.? to the outlet for disclwninn liquid Different parts of Fig.5 showing the assembly of the device of the present invention are as follows; 27.refers to the oscillating cum rotating light weight vessel of IDLP. 28.refers to the friction barf^U* 29.refers to the mechanism to fix the dome shaped cap to the vessel. 30.refers to the frame assembly to hold the vessel with entire mechanisms. 31.refers to the dome shaped cap. 32.refers to the main shafts held by bearings. Different parts of Fig. 6 showing the pictorial of the rotating & oscillation mechanisms of the device of the present invention are as follows: 33.refers to the clamp mechanism to hold and oscillate the main shaft. 34. refers to the friction roiiers. SS.refers to the connecting shafts of the friction rollers. 36. refers to the oscillating /rocking assembly. 37. refers to the power transmission source for oscillating of the vessel 38. refers to the driving mechanism for the connecting shafts. 39. refers to the power transmission source for rotation of the vessel. 40. refers to the supporting roller assembly. Different parts of Fig 7 (a) & (b) showing pictorial of the vessel of the device of the present invention are as follows: 41. refers to the perforated compartments with pegs. 42. refers to the perforated dummy door. 43. refers to the openable aperture for intermediate pH checking. 44. refers to the leak proof packing to avoid any leakage. 45. refers to the outlet to drain the liquid. 46. refers to the inlet for water, chemical solution and air. Different parts of Fig 8 showing the assembly of the pneumatic system of the device of the present invention are as follows; 47 refers to the source for air generation (by perpetual motion of the device). 48 refers to the air chamber. 49 refers to the valves. 50. refers to the air lifters to eject the solution from the container to the vessel 51 refers to the container for liquid. Accordingly the present invention provides an improved device for leather processing comprising a cylindrical vessel (27) encasing more than one perforated longitudinal compartments (41) characterized in that the said encasing fitted with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis, out of which at least one of them being openably fixed by conventional means (29) such as herein described, the said caps (31) being provided with co-centric inlets (46) and bottom draining outlets (45), the said caps being connected internally by perforated dummy disc door (42) having leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture (43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands (28) being provided on the side with supporting roller assembly (40) for preventing slippage during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of the vessel (27) in upward as well as downward directions, the said entire unit along with accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn connected to another power transmission source (37) so as to provide a combination of rotary as well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom with a conventional source for air pressure generation (47), air chamber (48), valves (49), air lifters (50), and chemical container (51) all connected by known conventional means such as herein described and forming a self generating pneumatic system for continuous addition of chemicals during processing, through the cap inlet (46), the entire said assembly being held by bearings supported rotatable main shaft (32) fixed onto main frame assembly (30). In an embodiment of the present invention, the material used for vessel, dome shaped cap, chemical container and perforated dummy door may be such as non-corrosive stainless steel, chemical resistant fiberglass reinforced polymer, seasoned wnnd In another embodiment of the present invention the material used for friction band, supporting roller assembly, friction roller, frame assembly, rocking/oscillating assembly, rotating assembly, main shaft, connecting shaft, clamp mechanism, may be such as stainless steel, mild steel, cast iron, teflon, nytrile rubber, fiberglass reinforced polymer. In yet another embodiment of the present invention, the bearings used may be such as self-aligned bearing, journal bearing, ball bearing. In still another embodiment of the present invention the conventional means used for opening as well as closing of the openable dome shaped cap may be such as bolt and nut assembly, rack and pinion assembly, pneumatic assembly, cam assembly. In a further embodiment of the present invention, the mechanism for rocking/oscillating assembly used may be such as cam mechanism, connecting rod mechanism, hydraulic system, spatial mechanism. In another embodiment of the present invention, the driving mechanism to rotate both upward and downward directions for the connecting shaft used may be such as gear drive, chain drive, belt drive. In yet another embodiment of the present invention, the leak proof packing material used may be such as hardened rubber, nytrile rubber, spongy rubber. In still another embodiment of the present invention the conventional source used for generating air pressure may be such as piston cylinder, air pumps, bellows. In a further embodiment of the present invention the material used for the friction rollers may be such as nytrile rubber, taflon, polyvinyl chloride, polyurethane, cast iron, brass, aluminium. In another embodiment of the present invention the power transmission source used may be a prime mover such as an electric motor. In yet another embodiment of the present invention, the material used for air chamber and air lifter may be such as stainless steel, mild steel, brass. The device of the present invention is described below in detail. The device is essentially a frame assembly (30) housing a vessel (27) divided into more than one perforated compartment (41) fitted with pegs. The compartments help in distributing the load throughout the vessel, thereby reducing the starting torque. Not less than two-friction disks (28) are fixed along the exterior periphery of the vessel (27). Friction disks (28) are positioned on friction roller (34), that rotates by the driving mechanism (38) connected to a power transmission source (39), through the connecting shafts (35), thereby enabling the vessel (27) to exhibit upward and downward rotary motion. A supporting roller assembly (40), positioned at one side of the disk (28) ensures that no slip occurs to the frame assembly (30) during the motion. There are two dome shaped, caps (31) on either side along the horizontal axis of the vessel (27). Both the caps are connected internally to perforated dummy door (42) along with leak proof packing (44) and are also provided with inlet (46) fixed at the center as well as outlet (45) at the bottom to drain out liquid. At least one of the dome shaped caps (31) is openable to ensure that the hides/skins to be processed can be put inside as well as taken out. The opening as well as closing of the dome shaped caps (31) is controlled by conventional locking mechanism (29). The entire unit, as described above, is connected to another known oscillating/rocking assembly (36), which drives its motion from another power transmission source (37), thereby ensuring rotary as well as oscillatory motion of the vessel (27). The bottom of the oscillating/rocking assembly (36), is provided with morti than one source for air generation (47), air chamber (48), valves (49) air lifter (50) and container (51), ail connected internally, thereby forming a pneumatic system, which is used for continuous addition of chemicals during processing. After all the chemicals are added to the vessel through the opened valve, air from the air chamber is led into the system, thereby generating inside the vessel pneumatic pressure, that quicken the processing. The entire assembly, as described above, is held by a main shaft (32) supported by two bearings. After taking the hide/skin to be processed inside the vessel (27) through the dummy door (42), the same is closed and the power transmission source (39) is switched on to start the rotary motion of the vessel (27). Then the power transmission source (37) is switched on to start the oscillatory motion of the vessel (27). The oscillatory motion of the (joyi/to facilitates d^avvinf1 ^ '*-'-? frorp ths sourc^ for Qensrsiiriri pjr ^47^ fixed at the bottom of the oscillatory assembly (36), and subsequent passing of the same air to the air lifter (50) through the air chamber (48) with the help of connecting lines and valves (49) facilitates letting the liquid from the container (51) into the vessel (27). Necessary chemicals are then ad'ded to the vessel from time to time. The persisting drawing of air after the transfer of the chemical solution from the container (51) to the vessel (27) facilitates generating of pneumatic pressure, which not only helps in uniform mixing of chemicals but also accelerates the processing. This rotary cum oscillatory motion of the vessel (27) ensures the stock under processing to multiple mechanical actions. Intermittent monitoring, if necessary, may be done by opening an aperture (43) provided on the external periphery of the vessel (27). At the end of the processing, the cap (31) is opened and the processed stock is unloaded by gravity. The novelty and non-obviousness of the present invention lies not only in providing a single vessel system exhibiting both oscillatory as well as rotary motion, thereby facilitating float turbulence as well as mixing of chemicals coupled with effective movement as well as automatic unloading of the hides/skins under processing, but also in using the oscillatory system of the device as a source for the generation of pressure inside the vessel and the pressure generated thereby being used as a pneumatic source for continuous addition of chemicals, thereby avoiding use of any external pneumatic source, resulting in economic utilization of energy and also providing a cost effective option for leather processing. The following examples are given by way of illustration only and therefore should not be construed to limit the scope of the present invention. Example 1 101 Kgs of limed buffalo pelt, duly fleshed and washed thoroughly, were taken in the fiber reinforced plastic vessel having three perforated compartments. The perforated dummy door and the dome'shaped cap, both made of fiber reinforced plastic, wpr then Hosed bv using bolt and nut assembly installed in the device. The leak-proof material used for the vessel was nytrile rubber. Water, measuring 100 Lts., was added to the vessel through the inlet for washing operations. The rotary and oscillatory mechanisms of the vessel were then switched on one by one. The vessel containing the pelt started oscillating at 8 oscillations per minute (opm) and rotating at 10 revolutions per minute (rpm) with the help of teflon rollers mounted on the mild steel connecting shafts. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by the hydraulic system and gearbox unit respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward just by changing the change over switch for easy mixing of chemicals with the water and for quickening the process. . « After a period of 15 minutes, the device was switched off and the water was drained out by opening the outlet. The same procedure was adopted for washing the pelt for second time. Water, measuring 70 Lt., was added to the vessel through the inlet for deliming operations, 1 kg of ammonium suifate was then dissolved in 5 lit. of water and the resulting solution was taken in the container, connected to the air pump, air chamber and valves through connecting lines. The device was switched on in the similar manner. The oscillatory motion of the device facilitated drawing of air from the air pump fixed at the bottom of the oscillatory assembly and subsequent passing of the same air to the air lifter through the air chamber with the help of connecting line and valve. The opening of the valve placed between the air chamber and the container facilitated in letting the liquid from the container into the vessel. As soon as all the liquid had been drawn in the vessel, the continued drawing of air facilitates the generation of phnumatic pressure, which was measured to be 3 kg/cm2, inside the vessel. After a period of 90 minutes, the vessel was switched off and the aperture was opened for pelt pH checking. The completion of deliming was confirmed using phenolphthalein indicator. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. Then the out let of the domed shaped cap was clo?^ The subsequent operation of washina, pickling, chrome tanning was carried out in a similar way. Completion of pickling was confirmed by opening the aperture in a way as already mentioned above. Exhaustion of chrome was also checked in a similar way by opening the outlet and taking out a sample of the chrome liquor in a glass container. Finally vessel was switched off and the domed shaped cap with the perforated dummy door was opened. The vessel was then positioned in a slanting condition by adjusting the oscillatory mechanism, which was stopped as soon as the vessel had assumed the said position. The rotary system was then switched on whereby the tanned wet blue was drawn out automatically by gravity. The leathers were then piled. Example 2 54 kgs of shaved weight wet blue were taken in the stainless steel vessel having two perforated compartments. The perforated dummy door both made of stainless steel, and the dome shaped cap of the vessel were then closed by using cam assembly installed in the device. The leak-proof material used for the vessel was spongy rubber. Water, measuring 50 Lt, was added to the vessel through the inlet for washing operation by adding 130 grams of formic acid and run for 30 minutes. After that the water was drained out by just opening the out let. The rotary and oscillatory mechanism of the vessel was then switched on one by one. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by the cam mechanism and gearbox unit respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward automatically by timer controlled system for easy mixing of chemicals with the water for quickening the process. The vessel containing the wet blue started oscillating at 10 opm, and rotating at 10 rpm with the help of the cast iron friction rollers mounted on the stainless steel connecting shaft. Water, measuring 50 Lts., was added to the vessel through the inlet for chrome tanning. 2.5 kgs Basic Chromium Sulfate powder dissolved in 5 lit. of pickle water and the resulting solution was added in one feed into the vessel through the inlet by manually. After a period of 40 minutes the vessel was switched off. The completion of chrome exhaustion was checked by collection the chrome liquor in a glass container. Then 320 grams of soda ash dissolved in 2 litres of water and the resulting solution was added in 3 feeds by manually. Then the drum was rotated as well as oscillated for a period of 30 minutes. The completion of neutralization operation was confirmed by opening the openable aperture for checking the pH of the leather. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. The device was again switched on after closing the same outlet. Water, measuring 50 Its., was added to the vessel through the inlet for Fatliquoring, dying and fixing operations'. Then 5.6 Kgs of synthetic fat liquor was emulsified well in hot water. The resulting fatliquor emulsion was added in to the oscillating vessel through the inlet. After a period of 35 minutes 350 grams of black dye was taken and mixed with 1 lit of water and the resulting solution added into the vessel, while allowing the device to oscillate for another 35 minutes and then 500 gms of formic acid, dissolved in 5 lit. of water was added to the vessel through the inlet in three feeds. After a period of 30 minutes the device was switched off. Then checked for exhaustion and for penetration. Finally the tanned leather was taken out by opening the domed shaped cap with the perforated dummy door kept the vessel in a convenient position and rotate the vessel for few minutes so as to unload the processed stock by gravity automatically and were piled. Example 3 185 Kgs assorted crust was taken in the in the stainless steel vessel having thee perforated compartments. The dome shaped cap with the perforated dummy door made of fibre glass reinforced polymer of the vessel was then closed by using rack and pinion mechanism installed in the device. The leak-proof material used for the vessel was nytrile rubber. Water, measuring 200 Its., was added to the vessel through the inlet for wetback operation by adding 1.5 kgs of wetting agent and 600 grams of ammonia. The rotary and oscillatory mechanisms of the vessel were then switched on one by one. The vessel containing the leather started oscillating at 4 opm and rotating at 6 rpm with the help of the nytrile rubber rollers mounted on the cast iron connecting shafts. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by tho spatial mechanism anri belt drive respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward automatically by timer controlled system for easy mixing of chemicals with the water and for quickening the process. After 6 hours the device was switched off and the leather was checked by opening the aperture. The wetting back was found o.k. After closing! the aperture the device was switched on and kept the vessel in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. Then the outlet was closed. Water, measuring 100 Lts., was added to the vessel through the inlet for Fatliquoring, dying and fixing operations. Then 18 Kgs of synthetic fatliquor was emulsified well in hot water. The resulting solution was taken in the container. Then device was switched on in the similar manner. The oscillatory motion of the device facilitated drawing of air from the air pump fixed at the bottom of the oscillatory assembly and subsequent passing of the same air to the air lifter through the air chamber with the help of connecting line and valve. The opening of the valve placed between the air chamber and the container facilitated in letting the liquid from the container into the vessel. As soon as all the liquid had been drawn in the vessel, the continued drawing of air facilitates the generation of pneumatic pressure, which was measured to be 2 kg/cm2, inside the vessel. After a period of 45 minutes 5 kgs of black dye was taken and mixed with 6 lits of water and the resulting solution added into the vessel as per the said method. The vessel was allowed to oscillate and rotate for another 60 minutes and then 750 gms of formic acid, dissolved in 5 lit. of water was added to the rotating vessel through the inlet continuously. After a period of 30 minutes the device was switched off. Then the aperture was opened. The liquor was collected for checking exhaustion of liquor. After that processed leather was taken out for checking uniform penetration of dye materials and found o.k. Finally the tanned leathers was taken out by opening the domed shaped cap with the dummy door and kept the vessel in a convenient position and rotate the vessel for few minutes so as to unload the processed stock by gravity automatically and were piled. Example 4 vessel having two perforated compartments. The dome shaped cap with the perforated dummy door of the vessel, made of stainless steel were then closed by using rack and pinion assembly installed in the device. The leak-proof material used for the vessel was spongy rubber. Water, measuring 150 Lt., was added to the vessel through the inlet for washing operation by adding 400 grams of formic acid. After 30 minutes the device was switched off and kept the vessel in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. Then the outlet was closed. The rotary and oscillatory mechanisms of the vessel were then switched on one by one. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by the hydraulic system and gearbox unit respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward automatically by timer controlled system for easy mixing of chemicals with the water and for quickening the process. The vessel containing the wet blue started oscillating at 8 opm, and rotating at 8 rpm with the help of the cast iron friction rollers mounted on the stainless steel connecting shafts. Water, measuring 150 Its., was added to the vessel through the inlet for chrome tanning. 7.5 kgs of Basic Chromium Sulfate powder dissolved in 15 lit. of water and the resulting solution was added in one feed into the vessel through the inlet by manually. After a period of 40 minutes the vessel was switched off. The completion of chrome exhaustion was checked by collection the chrome liquor by opening the outlet. After that the outlet was closed. Then 1 Kg of soda ash dissolved in 10 litres of water and the resulting solution was added in 3 feeds by manually for a period of 30 minutes. Then the drum was rotated as well as oscillated for another period of 30 minutes. The completion of neutralization operation was confirmed by opening the openable aperture for checking the pH of the leather, which was found to be 4.5. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. The device was again switched on after closing the same outlet. Water, measuring 150 Lts., was added to the vessel through the inlet for Fatliquoring, dying and fixing operations- Then 16 Kgs of synthetic fat liquor was emulsified weil in hot water. The resulting fatliquor emulsion was added in to the oscillating vessel through the inlet. After a period of 35 minutes 1 kg of black dye was taken and mixed with 3 lit of water and the resulting solution added into the vessel, while allowing the device to oscillate for another 35 minutes and then 1.5 Kgs of formic acid, dissolved in 10 lit. of water was added to the vessel through the inlet in three feeds. After a period of 30 minutes the device was switched off for checking. Finally the tanned leather was taken out by opening the domed shaped cap with the perforated dummy door, kept the vessel in a convenient position and oscillate the vessel for few minutes so as to unload the stock by gravity automatically and were piled. The main advantages of the present invention are the following. I.The vessel of the device undergoes rocking action, which enables an operator to adjust it in a convenient position so as to load and unload the processed stock by gravity automatically, thereby not only doing away with the extra labor associated with loading and unloading, but also in reducing time. 2.Since the light weight vessel is rotated by the friction rollers, the starting torque and the running torque of the device are equal, as against much higher values (three times) for the existing tanning drum, thereby reducing the power requirement considerably. S.The use of fabrication friendly materials like fiber reinforced plastic and stainless steel ensures ease in fabrication for the vessel, which is provided as a molded single unit structure for material saving, 4. Unlike in the conventional tanning drum, the device of the present invention ensures, the parameter like cross section pH of the leather and liquor pH can be measured by opening the aperture without opening the vessel main door thereby saving time at least 2 minutes for each time of monitoring. » 5. Unlike in the conventional tanning drum, the device of the present invention facilitates with short float for leather processing, resulting in better absorption of chemicals, higher exhaustion of bath and less effluent load to reduce the cost in production are ensured. B.This gentle multiple mechanical actions of the device facilitates easy movement of the goods inside the vessel to reduce the friction of skin slippage for quality improvement. 7.This vessel, is divided into compartments for distribution of working load (float + skin/side) and occupies 75 to 80 % of the volume of each compartment as in the conventional tanning drum concentrated load occupies only 35%. 8. Unlike in the conventional tanning drum where feeding of chemicai solution normally made manually, the device of the present invention facilitate addition of chemical solution into the vessel with the help of perpetual motion of the device. 9.Unlike in the conventional tanning drum where direction of rotation of the drum normally in one direction, the device of the present invention facilitate both upward and downward direction of the vessel apart from oscillatory motion to reduce the processing time. We claim: 1. An improved device for leather processing comprising a cylindrical vessel (27) encasing more than one perforated longitudinal compartments (41) characterized in that the said encasing fitted with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis, out of which at least one of them being openably fixed by conventional means (29) such as herein described, the said caps (31) being provided with co-centric inlets (46) and bottom draining outlets (45), the said caps being connected internally by perforated dummy disc door (42) having leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture (43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands (28) being provided on the side with supporting roller assembly (40) for preventing slippage during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of the vessel (27) in upward as well as downward directions, the said entire unit along with accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn connected to another power transmission source (37) so as to provide a combination of rotary as well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom with a conventional source for air pressure generation (47), air chamber (48), valves (49), air lifters (50), and chemical container (51) all connected by known conventional means such as herein described and forming a self generating pneumatic system for continuous addition ,of chemicals during processing, through the cap inlet (46), the entire said assembly being held by bearings supported rotatable main shaft (32) fixed onto main frame assembly (30) 2. An improved device, as claimed in claim 1, wherein the material used for vessel, dome shaped cap and perforated dummy door are such as noncorrosive stainless steel, chemical resistant fiberglass reinforced polymer, seasoned wood. 3. An improved device, as claimed in claims 1 - 2, wherein the material used for friction disk, supporting roller assembly, frame assembly, rocking/oscillating assembly, rotating assembly, main shaft, connecting shaft, clamp mechanism are such as stainless steel, mild steel, cast iron, Teflon nitrile rubber, fiberglass reinforced polymer. 4. An improved device, as claimed in claims 1 - 3, wherein the bearing used is such as self-alignea bearing, journal bearing, ball bearing. 5. An improved device, as claimed in claims 1 - 4, wherein conventional means (29) are selected from bolt and nut-assembly, pneumatic door assembly , cam assembly. 6. An improved device as claimed in claims 1-5, wherein the rocking/oscillating assembly used is such as cam mechanism, connecting red mechanism, hydraulic system, spatial mechanism. 7. An improved device as claimed in claims 1- 6, wherein the driving mechanism to rotate both upward and downward directions for the connecting shaft used is such as gear drive, chain drive, belt drive. 8. An improved device, as claimed in claims 1 - 7, wherein the leak proof packing material used is such as nitrile rubber, hardened rubber, spongy rubber. 9. An improved device for leather processing, as claimed in claims 1 - 8, wherein the material used for the friction rollers is such as nitrile rubber, teflon, polyvinyl chloride, polyurethane, cast iron, brass, aluminum. 10. An improved device as claimed in claims 1 - 9, wherein the material used for air chamber and air lifter is such as stainless steel, mild steel, brass. 11. An improved device for leather processing substantially as herein described with reference to the examples and figs 5 to 8 of the drawings accompanying the specification.

Full Text

The present invention relates to an improved device for leather processing. The device of the present invention has potential application in pre-tanning, tanning and post tanning wet operations in leather processing industry.
The wet processing of hides and skins are conventionally done in pit, vat, paddle and wooden drum. While using pit and vat, the hides/skins are put into the process liquor and handled manually. It has prompted -the tanners to use paddle to impart the agitation in the liquor by rotation of the blades of the paddle using motor and gearbox, thereby providing mechanical agitation to the stock to be processed. Much better effect of the desired mechanical action under dynamic condition on the hide/skin to be processed is however provided in a tanning drum, which has been in use since 1903. Rotational movement of the drum ensures that the skins/hides are first lifted up by the shelves or pegs and then allowed to fall down under gravity to the processing liquor, resulting in considerable mechanical action. As re'ported by Sharphouse (Leather Technician's Hand book -- year 1S71, Appendix 7 Pages 543 to 547 published by Leather producer's association) and K.T. Sarkar author and publisher (Theory and practice of leather manufactures -5th edition, year 1997- pages 732-761) this conventional drumming is associated with the following limitations.
a) It involves the possibility of damage of the sides/skins under processing,
by scrapping, scuffing, knotting, shape distortion, wrinkling, grain pebbling,
loosening of fiber structure or loss in area.
b) It is associated with difficulty in thorough cleaning of the stock, which lets
out lot of water adding to the effluent disposal problem.
c) It involves the inconvenience in opening the drum for unloading and other
intermittent checking.
d) Since the float of the drum cannot go beyond the axle level, the capacity
utilization is very low to the tune of only 35% of the volume of the drum.
e) Moreover, the turbulence generated in a tanning bath due to the rotational
movement of the device results not only in reduced diffusion of chemicals,
but also in enhanced friction among the surfaces of the skins/hides, thereby
contributing to the degradation of the quality of the final leather.
g) To process in short float as a measure against effluent problems, which

requires strengthening of drum drives, a higher motor power is required for
safe and efficient running.
h) Normally, the required starting torque, which plays an important role in the
selection of motor for any application, is very high to the tune of 3 times of
the running torque due to the following reasons.
1 .concentrated load of the hide/skin
2.Self-weight of the wooden tanning drum,
3.Friction because of the journal bearings and
4.The possible spur gear errors.
It is thus obvious that the motors used for running the drums are usually
oversized to take care of starting torque, resulting in poor efficiency under
normal running condition.
The above limitations have prompted the researchers to explore better options for leather processing device. Tombetti et al (Abstract published in Journal of American Leather Chemists Association, 75, 62, 1980) developed a pressure vessel for leather tanning, a assembly of which is shown in fig. 1 of the drawings accompanying this specification. The pressure vessel comprises, a rotating inner drum (2) divided into three perforated compartments, each having a door (6), housed in a stationary exterior casing (1) provided with a door (7) and an inlet for chemical and water housed on a frame assembly (3), the said inner drum (2) being rotated with the help of main shaft (4), held by two bearings and housing (5) and connected to a power transmission assembly source (8), the pressure inside the inner drum (2) being generated with the help of a pneumatic system (9).
It has been possible to enhance the capacity utilization to about 60% due to the provision of plurality of compartments provided in the pressure vessel. Moreover, the distribution of load, while the vessel is in motion ensures that the starting torque required for running the device is around 2 times of the running torque, thereby suggesting economy in energy consumption.

Nevertheless, the pressure vessel is also associated with the following limitations.
Association of moving parts with the inner vessel, which is connected to a rotating main shaft, has greater implication of wear and tear, that is likely to result in leakage of air, thereby causing loss of pressure inside the vessel. The stationary outer shell does not provide any option for automatic unloading of the leathers, which have to be taken out manually, thereby implying more labor as well as time.
Our copending Indian patent application No. 791/DEL/2000 as shown in fig. 2,3 & 4 of the drawings, has been an,attempt towards obviating the aforesaid limitations by way of providing an improved tanning device comprising a perforated inner vessel (15) having shelves more than one (17) and a door (16). The said inner vessel (15) being housed on non-corrosive chemical resistant rollers (18) fixed on the inner wall of the outer vessel (22) made up of a non-corrosive material capable of withstanding pressure of minimum 5 Kg/cm2, and the said outer vessel (22) being provided with a leak-proof packing (21) and dome shaped caps (20) on either side, the said outer shell being provided with inlet for chemicals and water (23), conventional regulated temperature device (24), discharge for liquid (26), a pressure nozzle (25) connected to a compressor and regulator externally (not shown in the drawing) for developing air pressure inside the vessel. The entire oscillating exterior shell (10) along with all accessories defined herein before being placed on center shaft (not shown in the drawing) being attached to the frame assembly (11). A conventional rocking mechanism (13) being provided on the outer shell and-connected to the normal power transmission assembly (12) in turn connected to the mechanism for rotating action (14) thereby ensuring rocking action as well as rotational movement of the inner perforated vessel (15) with the help of non corrosive chemical resistance gear (19) fixed on the outside of the inner vessel (15).
The main advantages of this device over the known pressure vessel are the following.
1.Unlike the known pressure vessel, where only rotary motion is possible, this device provides option for both oscillatory as well as rotary motion.

2.The outer shell of the device undergoes rocking action, which enables an
operator to adjust it in a convenient position so as to unload the processed
stock by gravity automatically, thereby not only doing away with the extra
labor associated with unloading, but also in reducing unloading tiine.
3.Since the inner vessel is rotated by the rollers fixed to the inside of the.
outer shell of the device, no leakage of internal pressure is envisaged and at
the same time long life is ensured for the device.
4.Unlike the existing systems, the starting torque of the device is only about
1.5 times of the running torque as against much higher values for the existing
devices, thereby reducing the power requirement considerably.
5..Capacity utilization of the device is around 70% as against 45% in the
existing wooden drum.
6.Even without opening the vessel door, the critical parameters like pH,
temperature of the float can be measured only by opening the outlet.
However, the device is still constrained by the following limitations.
The device provides a two-vessel system having an outer casing as well as
an inner vessel, thereby escalating not oniy the fabrication complexities, but
also cost.
An external energy source is required in the form of an air compressor to
form a pneumatic system, thereby adding to cost.
The device does not provide, like the conventional tanning drums, any option
for automatic mixing of chemicals inside the-drum, thereby implying the
requirement of proper mixing of chemicals.
The main objective of the present invention is to provide an improved device
for leather processing, which obviates the drawbacks stated above.
Another objective of the present invention is to provide a single vessel
system exhibiting both oscillatory as well as rotary motions like upward and
downward directions with less noise.
Yet another objective of the present invention is to provide a leather-tanning
device to employ pressure technique and at the same time to maintain the
internal pressure while processing leathers.
Still another objective of the present invention is to provide a device
exhibiting provision for automatic unloading of the processed stock.
Another objective of the present invention is to increase the capacity

utilization of the vessel to more than 75%.
Still another objective of the present invention is to ensure that the power
consumption and the processing time are reduced as compared to those in
the similar oper=ations in respect of the devices known in the existing art.
Yet another objective of the present invention is to provide a device to
process in short float as a measure against effluent problems by consuming
lesser energy compared to the conventional tanning drum.
Still another objective of the present invention is to provide a device
exhibiting provision for the chemical addition manually or mechanically.
The present invention provides an improved device for leather processing
comprising a vessel containing perforated dummy doors and compartments
with pegs as well as friction disk fixed along the exterior periphery of the
vessel. The leathers to be wet processed-are subjected to mechanical action
in terms of both rocking action as well as rotational movement
simultaneously. The perpetual motion of the device helps to create
pressure generation for quickening the process and for addition of chemical
solution continuously. The processing takes place under pressure generated
inside the vessel and with the support of multiple mechanical actions,
resulting in higher exhaustion of bath with less processing time and energy
requirement and higher capacity utilization to produce good quality leather.
In the drawings accompanying this specification :
Fig 1 represents the assembly of the existing pressure drum.
Fig. 2 represents the assembly and parts of the improved tanning device
(ITD), as described in our co pending patent application no. 791 DEL 2000
Fig. 3 represents the parts of the inner vessel of the ITD
Fig 4. represents the parts of the shell of the ITD
Fig 5. represents the assembly and parts of the Improved Device for Leather
Processing (IDLP) of the present invention.
Fig 6. represents the parts and pictorial view of the rotating & oscillation
mechanisms of the Improved Device for Leather Processing (IDLP) of the
present invention.
Fig 7. represents the pictorial view and parts of the vessel of the IDLP of the
present invention.
FigSr represents the assembly and parts of the pneumatic system of the

IDLP of the present invention.
Different parts of Fig. 1 showing assembly of the existing pressure drum are
as follows:
1. refers to the-stationary exterior casing
2. refers to the perforated inner rotating drum
3. refers to the frame assembly
4. refers to the center shaft
5. refers to the bearings and housings
6. refers to the perforated three compartments with each one door.
7. refers to the door to the exterior casing.
8. refers to the power transmission source.
9. refers to the inlet for chemical and water and with pneumatic system.
Different parts of Fig. 2 showing assembly of the improved tanning device (791/Del/2000) are as follows:
10. refers to the oscillating exterior shell.
11. refers to the frame assembly.
12. refers to the power transmission assembly.
13. refers to the mechanism for rocking action of the device
14. refers to the mechanism for rotating action of the device
Different parts of Fig. 3 showing details of inner vessel of the ITD (791/Del/2000) are as follows:
15. refers to the perforated inner vessel
16. refers to doors of the inner vessel
17. refers to the shelves/ compartments inside the inner vessel
18. refers to the rollers fixed on the inner side of the outer vessel
19. refers to the pinion & gear fixed on the outer side of the inner vessel
Different parts of Fig 4 showing details of shell of the ITD (791/Del/2000) are as follows:
20. refers to the dome shaped caps
21. refers to the leak proof packing
22. refers to the outer vessel

23. refers to the inlet for chemical and water
24. refers to the conventional regulated temperature device
25. refers to the nozzle connected with pressure regulator and compressor
26. refer.? to the outlet for disclwninn liquid
Different parts of Fig.5 showing the assembly of the device of the present
invention are as follows;
27.refers to the oscillating cum rotating light weight vessel of IDLP.
28.refers to the friction barf^U*
29.refers to the mechanism to fix the dome shaped cap to the vessel.
30.refers to the frame assembly to hold the vessel with entire mechanisms.
31.refers to the dome shaped cap.
32.refers to the main shafts held by bearings.
Different parts of Fig. 6 showing the pictorial of the rotating & oscillation
mechanisms of the device of the present invention are as follows:
33.refers to the clamp mechanism to hold and oscillate the main shaft.
34. refers to the friction roiiers.
SS.refers to the connecting shafts of the friction rollers.
36. refers to the oscillating /rocking assembly.
37. refers to the power transmission source for oscillating of the vessel
38. refers to the driving mechanism for the connecting shafts.
39. refers to the power transmission source for rotation of the vessel.
40. refers to the supporting roller assembly.
Different parts of Fig 7 (a) & (b) showing pictorial of the vessel of the device of the present invention are as follows:
41. refers to the perforated compartments with pegs.
42. refers to the perforated dummy door.
43. refers to the openable aperture for intermediate pH checking.
44. refers to the leak proof packing to avoid any leakage.
45. refers to the outlet to drain the liquid.
46. refers to the inlet for water, chemical solution and air.
Different parts of Fig 8 showing the assembly of the pneumatic system of the

device of the present invention are as follows;
47 refers to the source for air generation (by perpetual motion of the device). 48 refers to
the air chamber.
49 refers to the valves.
50. refers to the air lifters to eject the solution from the container to the vessel 51 refers
to the container for liquid.
Accordingly the present invention provides an improved device for leather processing comprising a cylindrical vessel (27) encasing more than one perforated longitudinal compartments (41) characterized in that the said encasing fitted with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis, out of which at least one of them being openably fixed by conventional means (29) such as herein described, the said caps (31) being provided with co-centric inlets (46) and bottom draining outlets (45), the said caps being connected internally by perforated dummy disc door (42) having leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture (43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands (28) being provided on the side with supporting roller assembly (40) for preventing slippage during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of the vessel (27) in upward as well as downward directions, the said entire unit along with accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn connected to another power transmission source (37) so as to provide a combination of rotary as well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom with a conventional source for air pressure generation (47), air chamber (48), valves (49), air lifters (50), and chemical container (51) all connected by known conventional means such as herein described and forming a self generating pneumatic system for continuous addition of chemicals during processing, through the cap inlet (46), the entire said assembly being held by bearings supported rotatable main shaft (32) fixed onto main frame assembly (30).

In an embodiment of the present invention, the material used for vessel, dome shaped cap, chemical container and perforated dummy door may be such as non-corrosive stainless steel, chemical resistant fiberglass reinforced polymer, seasoned wnnd
In another embodiment of the present invention the material used for friction
band, supporting roller assembly, friction roller, frame assembly,
rocking/oscillating assembly, rotating assembly, main shaft, connecting shaft,
clamp mechanism, may be such as stainless steel, mild steel, cast iron,
teflon, nytrile rubber, fiberglass reinforced polymer.
In yet another embodiment of the present invention, the bearings used may
be such as self-aligned bearing, journal bearing, ball bearing.
In still another embodiment of the present invention the conventional means
used for opening as well as closing of the openable dome shaped cap may
be such as bolt and nut assembly, rack and pinion assembly, pneumatic
assembly, cam assembly.
In a further embodiment of the present invention, the mechanism for
rocking/oscillating assembly used may be such as cam mechanism,
connecting rod mechanism, hydraulic system, spatial mechanism.
In another embodiment of the present invention, the driving mechanism to
rotate both upward and downward directions for the connecting shaft used
may be such as gear drive, chain drive, belt drive.
In yet another embodiment of the present invention, the leak proof packing
material used may be such as hardened rubber, nytrile rubber, spongy
rubber.
In still another embodiment of the present invention the conventional source
used for generating air pressure may be such as piston cylinder, air pumps,
bellows.
In a further embodiment of the present invention the material used for the
friction rollers may be such as nytrile rubber, taflon, polyvinyl chloride,
polyurethane, cast iron, brass, aluminium.
In another embodiment of the present invention the power transmission
source used may be a prime mover such as an electric motor.
In yet another embodiment of the present invention, the material used for air
chamber and air lifter may be such as stainless steel, mild steel, brass. The device of the present invention is described below in detail.
The device is essentially a frame assembly (30) housing a vessel (27)
divided into more than one perforated compartment (41) fitted with pegs. The
compartments help in distributing the load throughout the vessel, thereby
reducing the starting torque. Not less than two-friction disks (28) are fixed
along the exterior periphery of the vessel (27). Friction disks (28) are
positioned on friction roller (34), that rotates by the driving mechanism (38)
connected to a power transmission source (39), through the connecting
shafts (35), thereby enabling the vessel (27) to exhibit upward and downward
rotary motion. A supporting roller assembly (40), positioned at one side of the
disk (28) ensures that no slip occurs to the frame assembly (30) during the
motion. There are two dome shaped, caps (31) on either side along the
horizontal axis of the vessel (27). Both the caps are connected internally to
perforated dummy door (42) along with leak proof packing (44) and are also
provided with inlet (46) fixed at the center as well as outlet (45) at the bottom
to drain out liquid. At least one of the dome shaped caps (31) is openable to
ensure that the hides/skins to be processed can be put inside as well as
taken out. The opening as well as closing of the dome shaped caps (31) is
controlled by conventional locking mechanism (29). The entire unit, as
described above, is connected to another known oscillating/rocking assembly
(36), which drives its motion from another power transmission source (37),
thereby ensuring rotary as well as oscillatory motion of the vessel (27). The
bottom of the oscillating/rocking assembly (36), is provided with morti than
one source for air generation (47), air chamber (48), valves (49) air lifter (50)
and container (51), ail connected internally, thereby forming a pneumatic
system, which is used for continuous addition of chemicals during
processing. After all the chemicals are added to the vessel through the
opened valve, air from the air chamber is led into the system, thereby
generating inside the vessel pneumatic pressure, that quicken the
processing. The entire assembly, as described above, is held by a main shaft
(32) supported by two bearings. After taking the hide/skin to be processed
inside the vessel (27) through the dummy door (42), the same is closed and
the power transmission source (39) is switched on to start the rotary motion of the vessel (27). Then the power transmission source (37) is switched on to start the oscillatory motion of the vessel (27). The oscillatory motion of the (joyi/to facilitates d^avvinf1 ^ '*-'-? frorp ths sourc^ for Qensrsiiriri pjr ^47^ fixed at the bottom of the oscillatory assembly (36), and subsequent passing of the same air to the air lifter (50) through the air chamber (48) with the help of connecting lines and valves (49) facilitates letting the liquid from the container (51) into the vessel (27). Necessary chemicals are then ad'ded to the vessel from time to time. The persisting drawing of air after the transfer of the chemical solution from the container (51) to the vessel (27) facilitates generating of pneumatic pressure, which not only helps in uniform mixing of chemicals but also accelerates the processing. This rotary cum oscillatory motion of the vessel (27) ensures the stock under processing to multiple mechanical actions. Intermittent monitoring, if necessary, may be done by opening an aperture (43) provided on the external periphery of the vessel (27). At the end of the processing, the cap (31) is opened and the processed stock is unloaded by gravity.
The novelty and non-obviousness of the present invention lies not only in providing a single vessel system exhibiting both oscillatory as well as rotary motion, thereby facilitating float turbulence as well as mixing of chemicals coupled with effective movement as well as automatic unloading of the hides/skins under processing, but also in using the oscillatory system of the device as a source for the generation of pressure inside the vessel and the pressure generated thereby being used as a pneumatic source for continuous addition of chemicals, thereby avoiding use of any external pneumatic source, resulting in economic utilization of energy and also providing a cost effective option for leather processing.
The following examples are given by way of illustration only and therefore should not be construed to limit the scope of the present invention.
Example 1
101 Kgs of limed buffalo pelt, duly fleshed and washed thoroughly, were
taken in the fiber reinforced plastic vessel having three perforated
compartments. The perforated dummy door and the dome'shaped cap, both
made of fiber reinforced plastic, wpr then Hosed bv using bolt and nut
assembly installed in the device. The leak-proof material used for the vessel
was nytrile rubber. Water, measuring 100 Lts., was added to the vessel
through the inlet for washing operations. The rotary and oscillatory
mechanisms of the vessel were then switched on one by one. The vessel
containing the pelt started oscillating at 8 oscillations per minute (opm) and
rotating at 10 revolutions per minute (rpm) with the help of teflon rollers
mounted on the mild steel connecting shafts. The drive in respect of the
oscillatory and rotary motions of the vessel was drawn by the hydraulic
system and gearbox unit respectively. The direction of rotation of the vessel
changed for every 10 minutes to upward and downward just by changing the
change over switch for easy mixing of chemicals with the water and for
quickening the process. . «
After a period of 15 minutes, the device was switched off and the water was drained out by opening the outlet. The same procedure was adopted for washing the pelt for second time. Water, measuring 70 Lt., was added to the vessel through the inlet for deliming operations, 1 kg of ammonium suifate was then dissolved in 5 lit. of water and the resulting solution was taken in the container, connected to the air pump, air chamber and valves through connecting lines.
The device was switched on in the similar manner. The oscillatory motion of the device facilitated drawing of air from the air pump fixed at the bottom of the oscillatory assembly and subsequent passing of the same air to the air lifter through the air chamber with the help of connecting line and valve. The opening of the valve placed between the air chamber and the container facilitated in letting the liquid from the container into the vessel. As soon as all the liquid had been drawn in the vessel, the continued drawing of air facilitates the generation of phnumatic pressure, which was measured to be 3 kg/cm2, inside the vessel.
After a period of 90 minutes, the vessel was switched off and the aperture was opened for pelt pH checking. The completion of deliming was confirmed
using phenolphthalein indicator. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. Then the out let of the domed shaped cap was clo?^ The subsequent operation of washina, pickling, chrome tanning was carried out in a similar way. Completion of pickling was confirmed by opening the aperture in a way as already mentioned above.
Exhaustion of chrome was also checked in a similar way by opening the outlet and taking out a sample of the chrome liquor in a glass container. Finally vessel was switched off and the domed shaped cap with the perforated dummy door was opened. The vessel was then positioned in a slanting condition by adjusting the oscillatory mechanism, which was stopped as soon as the vessel had assumed the said position. The rotary system was then switched on whereby the tanned wet blue was drawn out automatically by gravity. The leathers were then piled.
Example 2
54 kgs of shaved weight wet blue were taken in the stainless steel vessel having two perforated compartments. The perforated dummy door both made of stainless steel, and the dome shaped cap of the vessel were then closed by using cam assembly installed in the device. The leak-proof material used for the vessel was spongy rubber. Water, measuring 50 Lt, was added to the vessel through the inlet for washing operation by adding 130 grams of formic acid and run for 30 minutes. After that the water was drained out by just opening the out let. The rotary and oscillatory mechanism of the vessel was then switched on one by one. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by the cam mechanism and gearbox unit respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward automatically by timer controlled system for easy mixing of chemicals with the water for quickening the process.
The vessel containing the wet blue started oscillating at 10 opm, and rotating at 10 rpm with the help of the cast iron friction rollers mounted on the stainless steel connecting shaft. Water, measuring 50 Lts., was added to the vessel through the inlet for chrome tanning. 2.5 kgs Basic Chromium Sulfate
powder dissolved in 5 lit. of pickle water and the resulting solution was added in one feed into the vessel through the inlet by manually. After a period of 40 minutes the vessel was switched off. The completion of chrome exhaustion was checked by collection the chrome liquor in a glass container.
Then 320 grams of soda ash dissolved in 2 litres of water and the resulting solution was added in 3 feeds by manually. Then the drum was rotated as well as oscillated for a period of 30 minutes. The completion of neutralization operation was confirmed by opening the openable aperture for checking the pH of the leather. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. The device was again switched on after closing the same outlet.
Water, measuring 50 Its., was added to the vessel through the inlet for Fatliquoring, dying and fixing operations'. Then 5.6 Kgs of synthetic fat liquor was emulsified well in hot water. The resulting fatliquor emulsion was added in to the oscillating vessel through the inlet. After a period of 35 minutes 350 grams of black dye was taken and mixed with 1 lit of water and the resulting solution added into the vessel, while allowing the device to oscillate for another 35 minutes and then 500 gms of formic acid, dissolved in 5 lit. of water was added to the vessel through the inlet in three feeds. After a period of 30 minutes the device was switched off. Then checked for exhaustion and for penetration. Finally the tanned leather was taken out by opening the domed shaped cap with the perforated dummy door kept the vessel in a convenient position and rotate the vessel for few minutes so as to unload the processed stock by gravity automatically and were piled.
Example 3
185 Kgs assorted crust was taken in the in the stainless steel vessel having thee perforated compartments. The dome shaped cap with the perforated dummy door made of fibre glass reinforced polymer of the vessel was then closed by using rack and pinion mechanism installed in the device. The leak-proof material used for the vessel was nytrile rubber. Water, measuring 200 Its., was added to the vessel through the inlet for wetback operation by adding 1.5 kgs of wetting agent and 600 grams of ammonia. The rotary and oscillatory mechanisms of the vessel were then switched on one by one. The
vessel containing the leather started oscillating at 4 opm and rotating at 6
rpm with the help of the nytrile rubber rollers mounted on the cast iron
connecting shafts. The drive in respect of the oscillatory and rotary motions
of the vessel was drawn by tho spatial mechanism anri belt drive
respectively. The direction of rotation of the vessel changed for every 10
minutes to upward and downward automatically by timer controlled system
for easy mixing of chemicals with the water and for quickening the process.
After 6 hours the device was switched off and the leather was checked by
opening the aperture. The wetting back was found o.k. After closing! the
aperture the device was switched on and kept the vessel in such a position
that the outlet was opened and faced downward, thereby letting the water out
by gravity. Then the outlet was closed. Water, measuring 100 Lts., was
added to the vessel through the inlet for Fatliquoring, dying and fixing
operations. Then 18 Kgs of synthetic fatliquor was emulsified well in hot
water. The resulting solution was taken in the container. Then device was
switched on in the similar manner. The oscillatory motion of the device
facilitated drawing of air from the air pump fixed at the bottom of the
oscillatory assembly and subsequent passing of the same air to the air lifter
through the air chamber with the help of connecting line and valve. The
opening of the valve placed between the air chamber and the container
facilitated in letting the liquid from the container into the vessel. As soon as
all the liquid had been drawn in the vessel, the continued drawing of air
facilitates the generation of pneumatic pressure, which was measured to be
2 kg/cm2, inside the vessel. After a period of 45 minutes 5 kgs of black dye
was taken and mixed with 6 lits of water and the resulting solution added into
the vessel as per the said method. The vessel was allowed to oscillate and
rotate for another 60 minutes and then 750 gms of formic acid, dissolved in 5
lit. of water was added to the rotating vessel through the inlet continuously.
After a period of 30 minutes the device was switched off. Then the aperture
was opened. The liquor was collected for checking exhaustion of liquor.
After that processed leather was taken out for checking uniform penetration
of dye materials and found o.k. Finally the tanned leathers was taken out by
opening the domed shaped cap with the dummy door and kept the vessel in
a convenient position and rotate the vessel for few minutes so as to unload
the processed stock by gravity automatically and were piled.
Example 4
vessel having two perforated compartments. The dome shaped cap with the perforated dummy door of the vessel, made of stainless steel were then closed by using rack and pinion assembly installed in the device. The leak-proof material used for the vessel was spongy rubber. Water, measuring 150 Lt., was added to the vessel through the inlet for washing operation by adding 400 grams of formic acid. After 30 minutes the device was switched off and kept the vessel in such a position that the outlet was opened and faced downward, thereby letting the water out by gravity. Then the outlet was closed.
The rotary and oscillatory mechanisms of the vessel were then switched on one by one. The drive in respect of the oscillatory and rotary motions of the vessel was drawn by the hydraulic system and gearbox unit respectively. The direction of rotation of the vessel changed for every 10 minutes to upward and downward automatically by timer controlled system for easy mixing of chemicals with the water and for quickening the process. The vessel containing the wet blue started oscillating at 8 opm, and rotating at 8 rpm with the help of the cast iron friction rollers mounted on the stainless steel connecting shafts. Water, measuring 150 Its., was added to the vessel through the inlet for chrome tanning. 7.5 kgs of Basic Chromium Sulfate powder dissolved in 15 lit. of water and the resulting solution was added in one feed into the vessel through the inlet by manually. After a period of 40 minutes the vessel was switched off. The completion of chrome exhaustion was checked by collection the chrome liquor by opening the outlet. After that the outlet was closed. Then 1 Kg of soda ash dissolved in 10 litres of water and the resulting solution was added in 3 feeds by manually for a period of 30 minutes. Then the drum was rotated as well as oscillated for another period of 30 minutes. The completion of neutralization operation was confirmed by opening the openable aperture for checking the pH of the leather, which was found to be 4.5. The aperture was then closed and the vessel was kept in such a position that the outlet was opened and faced
downward, thereby letting the water out by gravity. The device was again switched on after closing the same outlet. Water, measuring 150 Lts., was added to the vessel through the inlet for Fatliquoring, dying and fixing operations- Then 16 Kgs of synthetic fat liquor was emulsified weil in hot water. The resulting fatliquor emulsion was added in to the oscillating vessel through the inlet. After a period of 35 minutes 1 kg of black dye was taken and mixed with 3 lit of water and the resulting solution added into the vessel, while allowing the device to oscillate for another 35 minutes and then 1.5 Kgs of formic acid, dissolved in 10 lit. of water was added to the vessel through the inlet in three feeds. After a period of 30 minutes the device was switched off for checking. Finally the tanned leather was taken out by opening the domed shaped cap with the perforated dummy door, kept the vessel in a convenient position and oscillate the vessel for few minutes so as to unload the stock by gravity automatically and were piled.
The main advantages of the present invention are the following.
I.The vessel of the device undergoes rocking action, which enables an operator to adjust it in a convenient position so as to load and unload the processed stock by gravity automatically, thereby not only doing away with the extra labor associated with loading and unloading, but also in reducing time.
2.Since the light weight vessel is rotated by the friction rollers, the starting torque and the running torque of the device are equal, as against much higher values (three times) for the existing tanning drum, thereby reducing the power requirement considerably.
S.The use of fabrication friendly materials like fiber reinforced plastic and stainless steel ensures ease in fabrication for the vessel, which is provided as a molded single unit structure for material saving,
4. Unlike in the conventional tanning drum, the device of the present
invention ensures, the parameter like cross section pH of the leather and
liquor pH can be measured by opening the aperture without opening the
vessel main door thereby saving time at least 2 minutes for each time of
monitoring. »
5. Unlike in the conventional tanning drum, the device of the present
invention facilitates with short float for leather processing, resulting in better
absorption of chemicals, higher exhaustion of bath and less effluent load to
reduce the cost in production are ensured.
B.This gentle multiple mechanical actions of the device facilitates easy
movement of the goods inside the vessel to reduce the friction of skin
slippage for quality improvement.
7.This vessel, is divided into compartments for distribution of working load
(float + skin/side) and occupies 75 to 80 % of the volume of each
compartment as in the conventional tanning drum concentrated load
occupies only 35%.
8. Unlike in the conventional tanning drum where feeding of chemicai
solution normally made manually, the device of the present invention
facilitate addition of chemical solution into the vessel with the help of
perpetual motion of the device.
9.Unlike in the conventional tanning drum where direction of rotation of the
drum normally in one direction, the device of the present invention facilitate
both upward and downward direction of the vessel apart from oscillatory
motion to reduce the processing time.

We claim:
1. An improved device for leather processing comprising a cylindrical vessel (27) encasing more
than one perforated longitudinal compartments (41) characterized in that the said encasing fitted
with a plurality of pegs and having dome shaped caps (31) on either side along the horizontal axis,
out of which at least one of them being openably fixed by conventional means (29) such as herein
described, the said caps (31) being provided with co-centric inlets (46) and bottom draining
outlets (45), the said caps being connected internally by perforated dummy disc door (42) having
leak proof packing (44), the said vessel (27) being provided with a peripheral openable aperture
(43) and not less than two friction bands (28) fixed along its exterior periphery, the said bands
(28) being provided on the side with supporting roller assembly (40) for preventing slippage
during motion, the said vessel (27) being placed on friction rollers (34), the said rollers (34) being
rotated through connecting shafts (35) by a power transmission source(39) for rotary motion of
the vessel (27) in upward as well as downward directions, the said entire unit along with
accessories defined herein before being connected to a rocking/oscillating assembly (36) in turn
connected to another power transmission source (37) so as to provide a combination of rotary as
well as oscillatory motion, the said rocking/oscillating assembly (36) being provided at the bottom
with a conventional source for air pressure generation (47), air chamber (48), valves (49), air
lifters (50), and chemical container (51) all connected by known conventional means such as
herein described and forming a self generating pneumatic system for continuous addition ,of
chemicals during processing, through the cap inlet (46), the entire said assembly being held by
bearings supported rotatable main shaft (32) fixed onto main frame assembly (30)
2. An improved device, as claimed in claim 1, wherein the material used for vessel, dome shaped
cap and perforated dummy door are such as noncorrosive stainless steel, chemical resistant
fiberglass reinforced polymer, seasoned wood.
3. An improved device, as claimed in claims 1 - 2, wherein the material used for friction disk,
supporting roller assembly, frame assembly, rocking/oscillating assembly, rotating assembly,
main shaft, connecting shaft, clamp mechanism are such as stainless steel, mild steel, cast iron,
Teflon nitrile rubber, fiberglass reinforced polymer.
4. An improved device, as claimed in claims 1 - 3, wherein the bearing used is such as self-alignea
bearing, journal bearing, ball bearing.
5. An improved device, as claimed in claims 1 - 4, wherein conventional means (29) are selected
from bolt and nut-assembly, pneumatic door assembly , cam assembly.
6. An improved device as claimed in claims 1-5, wherein the rocking/oscillating assembly used
is such as cam mechanism, connecting red mechanism, hydraulic system, spatial mechanism.
7. An improved device as claimed in claims 1- 6, wherein the driving mechanism to rotate both
upward and downward directions for the connecting shaft used is such as gear drive, chain drive,
belt drive.
8. An improved device, as claimed in claims 1 - 7, wherein the leak proof packing material used is
such as nitrile rubber, hardened rubber, spongy rubber.
9. An improved device for leather processing, as claimed in claims 1 - 8, wherein the material
used for the friction rollers is such as nitrile rubber, teflon, polyvinyl chloride, polyurethane, cast
iron, brass, aluminum.

10. An improved device as claimed in claims 1 - 9, wherein the material used for air chamber and
air lifter is such as stainless steel, mild steel, brass.
11. An improved device for leather processing substantially as herein described with reference to
the examples and figs 5 to 8 of the drawings accompanying the specification.

Documents:

53-DEL-2002-Abstract.pdf

53-DEL-2002-Claims.pdf

53-DEL-2002-Correspondence-Others.pdf

53-DEL-2002-Correspondence-PO.pdf

53-DEL-2002-Description (Complete).pdf

53-DEL-2002-Drawings.pdf

53-DEL-2002-Form-1.pdf

53-DEL-2002-Form-18.pdf

53-DEL-2002-Form-2.pdf

53-DEL-2002-Form-3.pdf

53-DEL-2002-Petition-138.pdf

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Patent Number

233604

Indian Patent Application Number

53/DEL/2002

PG Journal Number

14/2009

Publication Date

27-Mar-2009

Grant Date

31-Mar-2009

Date of Filing

25-Jan-2002

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SUBRAMANIYAM KRISHNAN	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)
2	DURAISWAMY LAKSHMANAN,	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)
3	BOMMYA THANGARAJ	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)
4	NATESAN SAMIVELU	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)
5	PARUCHURI GANGADHAR RAO	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)
6	THIRUMALACHARI RAMASAMI	CENTRAL LEATHER RESEARCH INSTITUTE, ADYAR, CHENNAI-600020, (INDIA)

PCT International Classification Number

C14B 17/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA