Title of Invention

AN EQUIPMENT FOR MEASURING SLIDING RESISTANCE OF REFRACTORY MATERIALS AT VARYING TEMPERATURES

Abstract

A system for use in measuring sliding resistance of refractory, ceramic metal products both at cold and high temperatures and especially a system for use in measuring the abrasion resistance of any solid material both at ambient and high temperatures. In particular, the system is directed for use in measuring sliding resistance of refractory materials at varying temperatures and includes a fumace adapted to operate at varying temperatures, means for holding the test sample of said refractory material inside said furnace ; an abrading block /load adapted to be introduced into said fumace ; means for effective abrading motion of said abrading block over the sample surface to thereby simulate conditions for abrasion ; means for measuring various operating parameters of the furnace under which the simulated abrasion is effected. By identifying the weight difference between the sample prior to subjecting to abrasion and after the abrasion it is possible to determine the abrasion resistance using the standard Abrability Index Equation. The system is capable of measuring abrasion resistance of any solid material both at room and high temperatures of even upto 1500°C or more. With different sliding rates. The system would favour determining the abrasion resistance index of the products at various speed of the sliding block thereby determining the abrasion resistance under varying abrasion conditions at various loading rates depending on the type of sample, the loading block, quality and other related parameters.

Full Text

The present invention relates to a system for measuring sliding resistance of refractory, ceramic metal products both at cold and high temperatures and especially to a system for use in measuring the abrasion resistance of any solid material both at ambient and high temperatures. It is well known that different metallurgical furnaces are usually lined with bricks or blocks or castables. Refractory products used for such purpose should have very good high temperature abrasion resistance property. Importantly, the top surface of the refractory products are usually abraded because of sliding effect of molten metal/metal products over such refractory products. It is, therefore, important to determine the abrasion resistance of such lining materials against blasting of solid particles to ascertain the abrasion characteristics of the refractory material used in a particular furnace and its durability. It is presently known to use standard equipment and method for determining the abrasion resistance of such lining materials as provided and prescribed by British Standard Institution BS 1902 : Section 4.6 : 1985. In this regard reference is invited to the said British Standards wherein there is disclosed an apparatus and method to determine such abrasion resistance. Accompanying figures 1 and 2 illustrates such conventional application used to measure abrasion resistance of materials. As shown in Figures 1 and 2 the apparatus basically consist of an electric blower with variable transformer control, a calibrated venturi in which the abrasion grain is entrained in an air stream, a manometer, an abrasion chamber incorporating a test piece holder and an exhaust system to recover the abrasive grain. To facilitate the determination of resistance to abrasion using the apparatus, the later is further provided with a balance, scales, drying oven, stop watch, brown fused alumina grain, calibrated carbon blocks as test piece and test sieves. The above apparatus is known for use in determination of abrasion resistance of solid materials following the method of identifying abradibility index of a material (sample) using the standard equation. 2 Abradabity index wherein m1 - The initial mass of the dried test piece (in g); m2 - The mass of the abraded test piece (in g); Pb - The bulk density of the test piece (m g/cm3) C - The correction factor For the purpose of identification of the abradability index, the test pieces/samples are subject to a preparatory exercise wherein test pieces are obtained in the form of rectangular prism to initiate the test operation. The bulk density of each test piece is first determined and then the test pieces are dried to constant mass and thereafter cooled and weighed before abrasion tests are carried out. Thereafter, the test pieces are placed in the holder provided in the unit introduced through the front lid of the unit. Thereafter, securing the lid of the abrasion chamber. The method of abrasion using 6.35 +/- 0.01 kg of dry freshly sieved brown fused alumina grain is conducted on the test sample. After such abrasion is completed, the pieces are finally weighed to determine the extent of abrasion and determine the abradability method following the above equation. As would be evident from the above established British Standard for measurement of the abradability index ,BS : 1902, such devise and method is not suitable for determining the abrasion resistance against blasting of solid particles at higher temperatures and is restricted to only determination of abrasion resistance against blasting of solid particles at room temperature. Also it is not possible using the above known devise and method of measuring the abrasion resistance of solid particles to measure the abrasion resistance at various temperatures with different sliding rates. Moreover variation in abrasion resistance due to variation in speed of sliding block/abrasive factor is also not known/used following the above known device/method. 3 It is thus the basic object of the present invention to provide for a system capable of measuring abrasion resistance of any solid material both at room and high temperatures of even upto 1500°C or more. Another objection of the present invention is directed to provide a system to determine the abrasion resistance index of products at various temperatures with different sliding rates. Yet further object of the present invention is to provide or system for determining the abrasion resistance index of the products at various speed of the sliding block thereby determining the abrasion resistance under varying abrasion conditions. Yet further object of the present invention is directed to provide for a system for identification of abrasion resistance index at various loading rates depending on the type of sample, the loading block, quality and other related parameters. Summary of the Invention Thus according to the present invention, there is provided a system for use in measuring sliding resistance of refractory materials at varying temperatures comprising: a furnace adapted to operate at ambient/room temperature to a temperature of about 1500°C and having an enclosed inner chamber with an opening and a cover/lid for said opening ; said furnace inner chamber being obtained of high temperature resistant insulating material; means for holding the test sample of said refractory material inside said furnace ; an abrading block /load adapted to be introduced into said furnace ; means for effective to and fro motion of said abrading block over the sample surface to thereby simulate conditions for abrasion ; means for measuring various operating parameters of the furnace under which the simulated abrasion is effected. Preferably, in the above system the furnace is an electrically heated chamber furnace adapted to generate working temperature of upto 1500°C and above. 4 The said furnace is equipped with conventional gazettes/equipment along with means for identifying the number of sliding cycles. The-conventional gazettes/equipment comprise controller means including temperature controller and safety switches. The furnace inner chamber is obtained of high temperature resistant insulating type high alumina bricks and high temperature resistant alumina silicate fibers. Preferably, furnace in a chamber is obtained of high temperature resistant insulating type high alumina bricks followed by high temperature resistant alumina silicate fiber to provide a rectangular chamber. The chamber is enclosed from outside by temperature resistant steel sheet the heating elements comprise spiral type silicon carbide heating elements with matching resistances. Preferably, said heating chamber comprise 9 to 15 nos. preferably 12 nos. both end open spiral type silicon carbide heating elements having diameter of 12 to 16 mm. preferably 14 mm, hot zone length of 240 to 260 mm preferably 250 mm and over all length 600 to 700 mm preferably 650 mm with matching resistance. The controller means provided with said furnace comprise a) means for final temperature setting; b) means for identifying the rate of rise of temperature of the furnace during test period; c) means for identifying the r.p.m of the loading block movement; d) means for identifying total number of movement cycles; e) switch means for emergency put off; f) means for loading block movement; g) means for blind controller for safeguarding heating elements and over shooting of set temperature. The said means for final temperature setting is a switch, means for identifying the rate of rise of temperature of furnace during test period is a PID temperature controller-cum-indicator, means for identifying the r.p.m of the loading block movement is a controller unit, means for identifying total number of movement cycles is a recorder, the switch means for emergency put off is an emergency switch, means for loading block movement is a rotary controlling switch and means for blind controller for safeguarding heating elements and over shooting of set temperature is an additional PID controller. The base of the furnace is preferably made of silicon carbide having a "V" type groove used as a sample holder for rectangular samples. 5 The abrading block is made of selected material for withstanding low as well as high temperatures preferably silicon carbide, ceramic material and Inconei. The abrading block motion is adapted to generate 1 to 25 cycles/minute. For the purpose of effecting the to and fro motion of the abrading block In accordance with one embodiment, the said abrading block is fixed with two temperature resistant silicoff carbide bars fixed from two ends, one end is connected with a motorized drive adapted to push the abrading block with one external metallic frame attached with the other pusher rod which pulls the abrading block over the sample surface to constitute a complete cycle movement. The two high temperature resistant silicon carbide rods with clamp means are adapted to hold the abrading block from both sides. In accordance with another embodiment comprising means for providing circular movement of the abrading block over the test sample. The means for effecting to and fro movement of the loading block comprise means for varying the frequency of such motion, preferably from very low to very high frequency. In particular, the motion of the loading block over the sample is actuated by a mechanical motorized drive preferably having desired belt and pulley arrangement. The system is also preferably provided with means for maintaining the silicon carbide along with sample stationery and the abrading block adapted to move to and fro over the sample. The details of the invention its objects and advantages are explained hereunder in greater detail in relation to the non-limiting exemplary illustrations in relation to accompanying figure 3, which illustrates the system for determines abrasion resistance both at ambient and high temperatures in accordance with the present invention. As illustrated in Figure 3, the device of the invention basically comprise of a furnace comprising rectangular furnace refractory portion (FRP) having an 6 opening at the top which is covered by means of the furnace cover/lid (FL). To facilitate removal of the cover/lid (FL), the later is provided with a handle means (HM). The furnace is provided with silicon carbide heating elements which are operatively connected to the control cabinet (CC) having various operating/controller means including indicating lamp (IL), safety controller (SF), Ammeter (AM), main PID controller (PD), volt meter (VM), on/off control switches (SW), thyristor regulator (TR) and various push button switches (PBS). The furnace inner chamber is provided with means for holding the testing sample (refractory product) which is introduced after opening the cover/lid. Depending upon the product to be tested, the abrasive weight (load) is determined which is preferably in the form of a load block of varying weight. The abrasive weight (AW) is provided for achieving mechanical abrasion, on the test sample, by way of sliding to and fro motion on said test sample. For the purpose, the abrasive block is connected at its two sides with two silicon carbide rods having clamp means which are further connected to a piston type driving wheel to effectuate a mechanical arrangement for abrasion by effecting to and fro movement of the abrasive weight on the test sample. Importantly, the weight holder clamp is adapted to releaseably connect the abrasive weight (load) of different weights depending upon the sample to be tested. A reduction gear mechanism is provided to effectuate the mechanism for the said to and fro movement of the loading block. Most importantly, in the above discussed system of the invention it is possible to vary the temperature of the furnace from ambient to any higher temperatures say 1500°C or more by varying the furnace temperature and thus provide for controlled measuring of the abrasion resistance at various temperatures. Such test sample can comprise of a rectangular bar of size 25-30mm x 25-30mm x 150-200mm and abrasive load can be a block having weight of preferably 5 kgs. 7 By way of further illustration of the invention, the identification of initial mass of the test piece and mass of abraded test piece to calculate the abradibility index was carried out using the system of the invention. The results obtained using the system of the invention operated at 1200°C and 1500 cycles was carried out and the details are provided hereunder: Type of material Wt. loss (g/cm2) Zero cement castable (ZCC) with 95% AI2O3 0.0124 Self Flow Castables with 95% Al2O3 0.0076 ZCC (Commercial) 0.0011 As would be evident from the equation provided by the British Standard after having the weight loss data using the above discussed system of the invention it is possible to simply obtain abradibility index using the equation discussed above. It is thus possible by way of above discussed system of the present invention to provide for improvement in the art of measuring, the abradibility of various refractory materials. In particular, the above disclosure and the present invention provided for the following advantages: a. The system is capable to measuring the abrasion resistance of any solid material both at room and high temperatures upto 1500°C. b. The abrasion resistance index of the products can be measured at various temperatures with different heating rates. c. The abrasion resistance index of the products can be measured at various speeds of sliding block. d. The abrasion resistance index of the products can be measured at various loading rates, and depending on the type of sample, the loading block quality can be changed. The invention would thus provide for measurement of abrasion resistance at various temperatures and under different abrasion conditions and loading for simple and easy determination of abrasion resistance of any solid material. 8 WE CLAIM : 1. A system for use in measuring sliding resistance of refractory materials at varying temperatures comprising : a furnace adapted to operate at ambient/room temperature to a temperature - of about 1500°C and having an enclosed inner chamber with an opening and a cover/lid for said opening ; said furnace inner chamber being obtained of high temperature resistant insulating material; means for holding the test sample of said refractory material inside said furnace; an abrading block /load adapted to be introduced into said furnace ; means for effective to and fro motion of said abrading block over the sample surface to thereby simulate conditions for abrasion ; means for measuring various operating parameters of the furnace under which the simulated abrasion is effected. 2. A system as claimed in claim 1 wherein the furnace is an electrically heated chamber furnace adapted to generate working temperature of 1500°C and upto 1600°C. 3. A system as claimed in anyone of claims 1 or 2 wherein the said furnace comprise conventional gazettes/equipment alongwith means for identifying the number of sliding cycles as described herein. 4. A system as claimed in claim 3 wherein the conventional gazettes/equipment comprise controller means including temperature controller and safety switches. 9 5. A system as claimed in anyone of claims 1 to 4 wherein the controller means comprise: a) means for final temperature setting ; b) means for identifying the rate of rise of temperature of the furnace during test period ; c) means for identifying the r.p.m. of the loading block movement; d) means for identifying total number of movement cycles ; e) switch means for emergency put off; f) means for loading block movement; g) means for blind controller for safeguarding heating elements and over shooting of set temperature. 6. A system as claimed in anyone of claims 1 to 5 wherein the abrading block is made of selected material for withstanding low as well as at high temperatures preferably silicon carbide, ceramic material and Inconel. 7. A system as claimed in anyone of claims 1 to 6 wherein said means for effecting to and fro movement of the loading block comprise means for varying the frequency of such motion, preferably from very low to very high frequency. 8. A system as claimed in anyone of claims 1 to 7 wherein abrading block motion is adapted to generate 1 to 25 cycles/minute. 9. A system as claimed in anyone of claims 1 to 8 wherein the motion of the loading block over the sample is actuated by a mechanical motorized drive preferably having desired belt and pulley arrangement. 10. A system as claimed in anyone of claims 1 to 9 wherein for effecting to and fro motion of said abrading block there is provided from two opposite parallel sides of the furnace two high temperature resistant silicon carbide rods with clamp means to hold the abrading block from both sides. 10 11. A system as claimed in anyone of claims 1 to 10 wherein furnace inner chamber is obtained of high temperature resistant insulating type high alumina bricks and high temperature resistant alumino silicate fibers, 12. A system as claimed In anyone of claims 1 to 11 wherein furnace inner chamber is obtained of high temperature resistant insulating type high alumina bricks followed by high temperature resistant alumina silicate fibers to provide a rectangular chamber. 13. A system as claimed in claim 12 wherein the chamber is enclosed from outside by temperature resistant steel sheet. 14. A system as claimed in anyone of claims 1 to 13 wherein the heating elements comprise spiral type silicon carbide heating elements with matching resistances. 15. A system as claimed in claim 14 wherein said heating chamber comprise 9 to 15 Nos. preferably 12 nos. both end open spiral type silicon carbide heating elements having diameter of 12 to 16 mm preferably 14 mm, hot zone length of 240 to 260 mm preferably 250 mm and overall length of 600 to 700 mm preferably 650 mm with matching resistance. 16. A system as claimed in anyone of claims 1 to 15 comprising means for providing circular movement of the abrading block over the test sample, 17. A system as claimed in anyone of claims 1 to 16 wherein said abrading block is fixed with two temperature resistant silicon carbide bars fixed from two ends, one end is connected with a motorized drive adapted to push the abrading block with one external metallic frame attached with the other pusher rod which pulls the abrading block over the sample surface to constitute a complete cycle movement. 11 18. A system as claimed in anyone of claims 1 to 17 wherein the base of the furnace is made of silicon carbide having a "V" type groove used as sample holder for rectangular samples. 19. A system as claimed in anyone of claims 1 to 18 comprising means for maintaining the silicon carbide along with sample stationery and the abrading block adapted to move to and fro over the sample. 20. A system for measuring sliding abrasion resistance of refractory products at variable temperature substantially as herein described and illustrated with reference to the accompanying figures and examples. Dated this 30th day of January 2001. A system for use in measuring sliding resistance of refractory, ceramic metal products both at cold and high temperatures and especially a system for use in measuring the abrasion resistance of any solid material both at ambient and high temperatures. In particular, the system is directed for use in measuring sliding resistance of refractory materials at varying temperatures and includes a fumace adapted to operate at varying temperatures, means for holding the test sample of said refractory material inside said furnace ; an abrading block /load adapted to be introduced into said fumace ; means for effective abrading motion of said abrading block over the sample surface to thereby simulate conditions for abrasion ; means for measuring various operating parameters of the furnace under which the simulated abrasion is effected. By identifying the weight difference between the sample prior to subjecting to abrasion and after the abrasion it is possible to determine the abrasion resistance using the standard Abrability Index Equation. The system is capable of measuring abrasion resistance of any solid material both at room and high temperatures of even upto 1500°C or more. With different sliding rates. The system would favour determining the abrasion resistance index of the products at various speed of the sliding block thereby determining the abrasion resistance under varying abrasion conditions at various loading rates depending on the type of sample, the loading block, quality and other related parameters.

Documents:

00046-cal-2001-abstract.pdf

00046-cal-2001-claims.pdf

00046-cal-2001-correspondence.pdf

00046-cal-2001-description(complete).pdf

00046-cal-2001-drawings.pdf

00046-cal-2001-form-1.pdf

00046-cal-2001-form-19.pdf

00046-cal-2001-form-2.pdf

00046-cal-2001-form-3.pdf

00046-cal-2001-p.a.pdf

46-cal-2001-granted-abstract.pdf

46-cal-2001-granted-claims.pdf

46-cal-2001-granted-correspondence.pdf

46-cal-2001-granted-description (complete).pdf

46-cal-2001-granted-drawings.pdf

46-cal-2001-granted-examination report.pdf

46-cal-2001-granted-form 1.pdf

46-cal-2001-granted-form 18.pdf

46-cal-2001-granted-form 2.pdf

46-cal-2001-granted-form 3.pdf

46-cal-2001-granted-letter patent.pdf

46-cal-2001-granted-pa.pdf

46-cal-2001-granted-reply to examination report.pdf

46-cal-2001-granted-specification.pdf