Title of Invention

ROTARY COMPRESSOR

Abstract

The Invention in general relates to a Rotary Compressor and this compressor consists of a stator that houses a non revolving sleeve on which the holes are drilled and it is fitted on to an eccentric rotor. The rotor shaft driven by motor generates a rotary motion by V belt drive and it is supported at both ends by means of roller bearings housed in two end covers. The said rotor shaft has two slots at a detenmined distance and radial holes drilled on the slots opens into a long axial hole of the shaft for discharge of compressed air into reservoir. There Is a blade integral with the sleeve is oscillated by air-tight seals within the stator and the stator is divided into two segments enabling compression and intake of air-oil mixture to take place simultaneously. Thus this invention reduces the noise level and the performance of Compressor is achieved by nitrocarburising process treatment to all moving and mating parts.

Full Text

This invention relates to compressors more particularly the pressure release mechanism and structure o-f rotary piston compressors, BACKGROUND OF THE INVENTION Rotary piston has been around for years in liquid pumps, vacuum pumps and engines, the rotary principle which is well described in patents (1,623,315), (2,643,817) & (3,044,686). The rotary pistons compressors in general work on the principle of having an intake valve designed to control the pressure and pressure release of the compressor. It involves utilising valve and valve seat notching and notching to prevent leaks. It also involves usage of spring. Springs generally tend to lose its mechanical properties due to wear, tear and fatigue, which eventually leads to losing elasticity of the springs- For the reasons mentioned above, discharge of pressure is at a lower value than the preset values. The characteristics of the spring affects the entire pressure control and hence affects the efficiency of the compressor. The existing systems, particularly the rotary piston compressor covered by patent no. 3,044,686 employ valve seats, poppet valves and springs on the side face of the compressor to control the pressure and pressure release of the compressor. This has an inherent problem of valve and valve seat matching and mating to prevent leaks, springs usually have a tendency of losing its mechanical properties due to fatigue which results in losing elasticity and eventually settling o-f the springs. This could lead to discharge of pressure at lower than preset values. The poppet valve, spring combination affects the entire efficiency of the compressor, in terms of pressure or in terms of discharge, as it is totally dependent on the characteristics of the spring- This becomes especially true when the system works at high speeds, upward of 1500 rpm as the frequency of opening and closing increases. OBJECT OF THE INVENTION It is the object of the invention to replace the existing valve mechanism. It is another object of the invention is to design a system, in which the efficiency of the system is ensured by precision in the manufacturing stage itself and is not dependent on any component of the system like the spring. It is another object of the invention to overcome all problems related to the existing systems. It is another object of the invention to design a compressor which is highly efficient, guiet in operation and low in cost. It is another object of the invention to design a compressor which has minimum moving parts. It is another object o-f the invention to design a compressor, with proprietary sur-face treatment process for mininiizing wear and enhancing the li-fe of the compressor- BRIEF DESCRIPTION OF THE INVENTION The compressor consists of an eccentric rotor, which actuates a non-rotating sleeve connected to a piston rod. This piston rod reciprocates while it is held in position by oscillating guides- The conibination of a rotary motion of the eccentric rotor, oscillating motion of the guides and reciprocating motion of the piston results in the gyration of the rotary piston within the cylinder in such a way as it sweeps the entire volume, the air is constantly drawn on one side of the piston and compressed on the other- Sealing is done by means of oil, which is being compressed alongwith air. This oil also lubricates and cools the system. The pressure build up and release is achieved by a novel method in the invention. The compressed air is discharged through the eccentric shaft of the rotor. During the matching of the 2 holes in the rotor and sleeve, the compressed air and oil is released through the sleeve into the rotor. Holes drilled in the eccentric rotor connect to a long axial hole drilled in the rotor shaft, which releases the compressed air and oil into a reservoir. The meshing of the holes in the non-rotating sleeve and eccentric rotor is so designed to ensure that slots incorporated on the eccentric rotor- are machined at speci-fied orientation and calculated length, in order to allow pre-designed time -for the discharge of the compressed air-through the axial hole into the reservoir. Both compressed air and oil are discharged through the outlet o-f the compressor. The mixture is thrown out tangentially to create a cyclonic effect. The oil gets separated and clean air- flows into the subsequent stages of separation. This also cools the air to a great extent. ILLUSTRATION OF DRftWINGS As per the invention, the pressure build up and release, is achieved by a novel method. The compressed air is discharged through the eccentric shaft of the rotor. Fig.l to Fig.4 define and illustrate the basic mechanism of the rotary piston. The action starts in fig.4 where the two holes in the rotor and sleeve match. The compressed air and oil is released through the sleeve into the rotor. Holes drilled in the eccentric rotor connect to a long axial hole drilled in the rotor shaft, which releases the compressed air and oil into a reservoir. The meshing of the holes in the non-rotating sleeve and eccentric rotor is very critical and to ensure this the design of the eccentric rotor incorporates slots which are machined at specified orientation and calculated length in order to allow pre-designed time for the discharge of compressed air through the axial hole into the reservoir. This mechanism is the essence o-f the invention which is personified in its simplicity and innovation. It does away with complex valving mechanisms and problems related to it. The e-f-ficiency of the system is design related and ensured by precision in manu-facturing and not dependent on li-fe / -functioning o-f a component like the spring. Fig.l to Fig.4- shows the principle of the working o-f the rotary compressor and the discharge through the central port. Fig.5 gives the transverse cross section of the compressor, which clearly shows the eccentric rotor with the slot and its connection of the central hole. The non-rotating sleeve with the holes for meshing with the slot and allowing discharge of air is also visible in this drawing. Fig.6 Longitudinal cross sectional view showing the complete assembly, including the discharge port for throwing the compressed air and oil in a tangential manner. Fig.7 shows the slot in the outlet port at a specific angle o o between 30 C and 45 C to the orientation of the plane parallel to the sides of the key way. Fig.8 and 9 Typical micro structure of optimized. Fig.10 and 11 Sursulf treatment before and after running in period are shown. Fig,12 shows air and oil flow schematic. DESCRIPTION OF INVENTION The compressor consists of :- Stator This encloses a non revolving sleeve, inside which is an eccentric rotor. The compression of air takes place in this. Rotor This is an eccentric shaft, driven by means of a motor and belt drive. Due to its eventricity, it makes the sleeve move (non-rotating) along the inner circumference of the Stator, always maintaining a line contact with the Stator. ft long axial hole is drilled in the rotor shaft and the radial holes drilled on it opens into this long axial hole for discharge of compressed air into the reservoir. Sleeve This is the non-revolving part that compresses the air-oil ndxture inside the stator, by virtue of its motion. The sleeve has ports/holes drilled on it- fit the end of the compression stroke these ports/holes and the radial holes on the rotor shaft coincide, allowing the compressed mixture to pass axially through the rotor shaft to the reservoir. Blade This is integral to the sleeve and actually compartmentalizes (along with the line contact of the sleeve) the stator longitudinally into two enabling compression to take place in one half and the air intake to take place on the other sinmltaneouslyw This follows an oscillating as well as sliding motion, pressed tightly against, by the seals. Seals These give air tight sealing to the stator, between which the blade executes the sliding movement, In ^^ery close contact, Also this enables the blade to have the oscillatory motion. End covers These close the stators at the two ends enabling the stator to have a leak tight enclosure. These also support the rotor-shaft at the two ends on roller bearings, housed in it. Oil Reservoir This holds the necessary oil for the compressor-operation- The self-pressure generated in it enables the injection of oil into the stator to form the,air-oil mixture for compression. The compressor consists of a stator that houses a sleeve, which is non revolving. The sleeve is fitted on to an eccentric rotor with clearance to allow the rotor to rotate within it. The rotor shaft is supported at both ends by means of roller bearings housed in the two end covers. The rotor is driven by a motor through V belt drive- The sleeve has ports/holes drilled on to it. The rotor has two slots at a determined distance (the dimensions of the slots is also determined. Radial holes/ports are drilled on these slots. These radial holes on the rotor open into a long hole drilled axially on the rotor shaft. It is through this axial hole that the compressed air is discharged into the reservoir. It is these ports/holes and the timed mating/matching o-f these ports/holes that brings out the uniqueness of the invention - "Timed Discharge Porting" doing away with the moving parts like valves springs, etc. used for pressure controlling/release - thus increasing the efficiency of the compressor. The blade, integral with the sleeve, has sliding/oscillatory motion and divides the stator into two segments enabling compression and intake to take place simultaneously. The oil reservoir holds the oil for use during operation and the self pressure enables the oil injection into the stator- The compressor has an all Cast Iron construction for reliability- The operation begins with the intake of air-oil mixture into the stator and the rotor begins to rotate from the top position (fig. 1) On further rotation of the rotor and the consequent movement of the sleeve, the inlet mixture gets further compressed. Now as the rotor completes its half rotation the intake cycle as well as the compression cycle takes place. At the end of one revolution of the rotor, the compression cycle is complete and now the ports/holes in the sleeve match/mate with the holes/ports in the rotor, enabling the compressed mixture to pass through and then into the axial hole in the rotor sha-ft to the reservoir- As this compressor discharges through its outlet both compressed air and oil, this oil has to be e-f-ficiently removed from the compressed air. This is innovatively done by throwing the air oil mixture tangen-tially to create a cyclonic effect and oil gets separated out and clean air flows into the subsequent stages of separation. This also cools the air to a great extent. This invention also takes into consideration various aspects of design in order to make the compressor highly efficient, guiet in operation and low in cost such as low number of moving parts, high speed of operation, proprietary surface treatment process for minimising wear and enhancing life. It is guite obvious that high speeds are of utmost importance in operating a vacuum pump based on the above rotary principle. In any slow moving pump, the oil in the system has time to give up , the air it carries, back to the vacuum. If the speed of the vacuum pump is high enough oil will not have time to discharge the air. Hence, everything said about the vacuum pump is equally applicable to the compressor. As speed of rotation is an important factor for efficiency of pumping, it is important to note that as speed of the system increases the noise level and wear of the parts increase significantly, fis the object of the invention is also to have a guiet and efficient compressor, the running or mating parts were surface engineered so a» not to change the base property o-f the materials used, but to enhance the surface property to an extent to extend the wear life of the materials used, which in effect has an impact in reducing the noise level of the compressors-One such treatment utilized by us is SURSULF. SURSULF is an accelerated Witrocarburising process used for a wide variety of ferrous materials like steel, cast iron. The components after treatment have a wear resistant diffusion layer, which enhances the life of the components. Besides, SURSULF treatment reduces the problem of scuffing and seiirure encountered by the components. The treated components have a compound zone and a nitrogen diffusion zone. Typically the process o consists of a molten salt bath, maintained at 570 C and the components are immersed in the bath for a specific period of time. SURSULF process not only increases the wear life of the materials used in the compressor but also increases the volume co-efficient of the surfaces in contention. This is done by the micro roughening of the surface, which helps in increasing the oil retaining capacity of the surfaces. Trials have been done to this effect where very smooth i.e. ground and polished surfaces were used and it was found that there was a decrease in the output of the compressor. Two aspects of the treatment were studied - (i) regarding the influence of the compound zone of the Sursulf layer (ii) the micro roughening caused by the surface treatment. In the -first case the treatment was done at di-fferent parameters, compound zone of 2 microns at one end o-f the spectrum and compound zone o-f 19 microns at the other end and it was optimized to get a compound zone of 5 " 10 microns- Measurements of the thickness of the compound zone were made after the components have been in operation for 1000, 1500 and 2000 hours, the initial thickness of compound zone was 9 microns (fig«8). In all the cases only slight wear was observed and after 1500 and 2000 hours in operation, the thickness of the remaining layer was measured to be 6 and 4 microns. It has been found that the optimized thicknesses between 5-10 microns gave the best results from the surface roughness point of view, 1 - 1.2 urn The objective of the invention is to utilize the micro roughening characteristics of the Sursulf treatment to improve the volume co-efficient of the oil film and also to improve the efficiencies. further by controlling the process parameters. Typical micro structure of the optimized Sursulf treatment before and after running in period are shown in"Fig.8 and Fig.9. we Claim : Claim 1 s A rotary compressor comprising s a. A stator housing- b- ft non-revolving sleeve in said stator housing, having holes drilled on it-c- A motor and belt drive. d. ft rotor shaft driven by said motor and said belt drive to generate a rotary motion- e. Said rotor shaft is eccentric, such that said sleeve always moves alongwith inner circumference of said stator, always maintaining a line of contact with said stator. f- Said motor shaft is supported at both ends by means of roller bearings housed in two end covers- g. Said end covers close the said stators at two ends, thus enabling the said stator, to have leak tight entry thereby. h. Said rotor shaft having a long axial hole and two slots, said two slots are of determined dimensions and at a determined distance, radial holes are drilled on said slots, said radial holes open into the said long axial hole for discharge of compressed air into reservoir- i« ft blade attached to said sleeve, to be oscillated thereby within said stator for longitudinally dividing the said stator into two segments so that compression takes place on one half of the stator and intake takes place in another half of stator simultaneously; said blade being oscillated by air-tight seals; said blade also executes the gliding movement between said seals. Claim 2 s ft rotary compressor as claimed in claim 1 wherein liquid is used as sealing and lubricating medium. Claim 3 : A rotary compressor of claim 1 wherein all running or mating parts are subjected to Nitrocarburising treatment; so as to have a micro surface roughness between 0.6 um and 1.0 um Ra so as to increase the wear life of the materials and increase the volume co-efficient of the surfaces by increasing the oil retaining capacity of surface- Claim 4 : A rotary compressor of claim 1 and 3, wherein said Nitrocarburising treatment is SURSULF, which is an accelerated Nitocarburlsing process-Claim 5 : A rotary compressor of claim 1 and 4, wherein SURSULF treat- o ment means a process consisting of molten salt bath, maintained at 570 C and the components are immersed- in the bath for a specific period of time to get a treated component. Claim 6 : ft rotary compressor according to claim 1 and treated components according to claim 5 wherein, treated components comprises of :- a. having compound zone and a nitrogen diffusion zone. b. surface is micro roughened. Claim 7 : ft rotary compressor according to claim 1 and claim 6, wherein thickness of compound zone is between 5-10 microns; surface roughness is between 1 - 1.2 um and average surface roughness is 0.75 um Ra. Claim 8 : A rotary compressor according to claim 1, wherein discharged mixture of air and oil through the outlet is thrown tangentially to create a cyclonic effect. The oil gets separated out and clean air flows into the subsequent stages of separation. This also cools the air to great extent. Claim 9 : ft rotary compressor according to claim 1, as substantially described in complete specification. Claim 10 : ft rotary compressor according to claim 1, as illustrated in drawings l-li.

Documents:

241-mas-2000-abstract.pdf

241-mas-2000-claims filed.pdf

241-mas-2000-claims grand.pdf

241-mas-2000-correspondence other.pdf

241-mas-2000-correspondence po.pdf

241-mas-2000-description complete filed.pdf

241-mas-2000-description complete grand.pdf

241-mas-2000-drawings.pdf

241-mas-2000-form 1.pdf

241-mas-2000-form 19.pdf

241-mas-2000-form 26.pdf