328 



THE INDIA RUBBER WORLD 



[March 1, 191/. 



ASrUSTABLE HIGH-TXHFEBATURE BVBNEB. 



'HE illustration sliows a high-tempcralurc burner adjustable 

 both as to the air and gas supply, and suitable for use 

 with any gas except acetylene. An important 

 feature in this form of burner is that the 

 flame may be controlled without changing 

 the position of the crucible, due to the fact 

 that the chimney does not move in its adjust- 

 ment. It is particularly desirable in opera- 

 tions which call for a blast lami). [E. H. 

 Sargent & Co., Chicai;o. Illinois.] 



THE SHORE SCI.ER0SC0PE. 



Tlie standard sclcro- 

 scope is now provided 

 with a special hammer 

 for use in testing the re- 

 b.mnd of cured rubber, in 

 place of the diamond-pointed hammer used 

 on metals. This instrument is well known 

 all over the world in connection with testing 

 the hardness of metals by measuring the re- 

 bound under a definite blow from a hammer 

 raised and released pneumati- 

 cally from a constant height. 

 The illustration shows the 

 instrument mounted for testing small 

 specimens. It is easily detachable 

 from its base for operation on a swing 

 arm for testing larger pieces on a 

 bench. It may also be used free hand 

 for testing still larger pieces in any 

 location. [Shore Instrument & Manu- 

 facturing Co., New York City.] 



CONTROL OF FACTORY OPERATIOKS. 



In an article on Factory Control and Research ("The Times 

 Trade Supplement," London, December, 1916), Mr. W. A. 

 Williams discusses the functions of the rubber chemist in relation 

 to manufacturing problems. He suggests that laboratory control 

 should be divided into three departments : 



A. Dealing with chemical questions other than those concerned 

 with actual operations, including all research work, the investiga- 

 tion of competitors' productions, the improvement of current 

 manufacturing operations and the investigation and perfecting of 

 new lines of manufacture. 



B. Dealing with all actual production operation ; control of 

 the finished factory production, checking against specification and 

 standard qualities, including control of power plant and steam 

 raising. 



C. Dealing with production of compounds for standard factory 

 specifications, and investigation of new compounds. 



The latter department should be equipped with a manufacturing 

 plant on a small scale, with which all investigations of running 

 and vulcanizing can be carried out, and where tests can be made, 

 independent of the large-scale factory operations. These under 

 no conditions should be interfered with. Experimental work 

 should be kept entirely out of the factory. It is only when the 

 experiments have been completed and standardized that the 

 operations on a large scale should be adopted. 



The functions of departments B and C are in connection with 

 the daily work of the factory, in order to ensure smooth and 

 efficient operation, and reliability of the finished products. Their 

 operations are concerned with the manipulation of the grades of 

 rubber employed in specific classes of articles and with the many 

 other ingredients entering into manufacturing operations. 



SCLEROSCOPE AND BALL REBOUND. 



Contributed. 



"T^HE accompanying chart shows the relative rebound of 

 * various qualities of rubber pump valves, solid tires, 

 vulcanite and other ordinary qualities. 



The tests were made in connection with a study of pump 

 valves. The Shore Scleroscope was used with a special rub- 

 ber hammer, having a small flat steel striking face in place 

 of the usual diamond point used in tests on metals. 



The ball rebound was obtained from the same rubber 

 samples from which balls were cut, of three-quarter-inch di- 

 ameter. These were dropped from a height of about 20 times 

 their diameter onto a smooth cast iron base supporting a 

 scale identical with that used in the scleroscope. 



Tlie different rubbers used differed widely in specific gravity 

 and composition, but these differences do not influence the 

 agreement of the rebound of the scleroscope and ball method. 



The straight line drawn through the plotted readings passes 

 from zero through 100, the rebound of a ball of pure unvul- 

 canized Para rubber, whereas the scleroscope on this ma- 

 terial showed 95. 



Thus all scleroscope readings may be taken as representing 

 95 per cent of the height of rebound which could be obtained 



10 to yi 4Q so to 7« io 90 i« >io 



with a ball made of the same rubber dropped from a height 

 approximately 15 or 20 times the diameter of the ball. 



The numbered plottings correspond to the following de- 

 scriptive list of samples. 



Numbers 1 to 6 inclusive are rather hard but of low 

 elasticity. 



All tests were made at 65 to 73 degrees. 



LIST OF SAMPLES CHARTED. 



