March 1, 1913.] 



THE INDIA RUBBER WORLD 



295 



W 



Some Observations on the Testing of Steam and Air-Brake Hose 

 Used on Railway Locomotives and Cars. 



By G. C. Bishop. 

 {Superintendent Motive Power of the Long Island Railroad Co.) 



in service. The different makes of hose are designated by the let- 

 ters "A" to "H" inclusive. 



It will be noticed that a large proportion of the hose is re- 

 moved because of being damaged in service. This is largely 

 due to the automatic connector, which increased the chaling 

 and cutting of hose. 



Little can be learned from makes "B" and "H," as they represent 

 purchases made three years ago, and only the oldest hose was 

 removed in the period covered by our data. It is interesting, 

 however, to note that the removals of "B" hose represent a 

 comparatively high percentage of the amount purchased, and 

 the high average life checks with the high average characteristics 

 shown by the tests. 



"F"' hose, it will be noted, shows a large percentage of rejec- 

 tions and from our inspection of the results of the tests the 

 reason is apparent. The friction is below the average, and the 

 stretch just passes. Although the bursting tests are not shown, 

 the rejections are numerous and the lots accepted were just 

 within the requircnients. This hose was all purchased in the 

 year 1912. 



"A" shows a fair life, and the results of the tests closely ap- 

 proach the general average. 



"C" represents one purchase only, but the test results were uni- 

 form and very good ; the explanation of the low life is that the 

 hose was soft and a considerable quantity failed shortly after 

 application due to inability to properly clamp the hose around 

 the nipples. 



"D" shows a good life, even though the percentage of damaged 



PREP.\RED FOR THE THIRD INTERNATIONAL RUBBER CON- 

 FERENCE. HELD IN NEW YORK IN 1912. 



!•'. will first consider air-brake hose of V/s, inch x 22 inches 

 and \% inch x 22 inches. We will pass over sizes and 

 badge plates, which are not important as far as the ob- 

 servations in this paper are concerned. On a certain sample of 

 hose the specification called for (1) a bursting pressure of 500 

 pounds per square inch exerted for 10 minutes; (2) at a pressure 

 of about 200 pounds per square inch, the hose must not expand 

 in diameter more than one-quarter inch or change in length more 

 than one-quarter inch ; (3) a friction test : with a weight of 25 

 pounds suspended from the end the separation must be uniform 

 and regular and the average speed must not exceed six inches 

 in 10 minutes ; (4) a stretch test : between marks two inches 

 apart on a piece one-half inch wide, stretched quickly until the 

 marks are 10 inches apart, released, then re-marked as at first 

 and again stretched to 10 inches, the specimen must remain 10 

 minutes without breaking; and (5), after release the distance 

 between the marks nuist not show a permanent set of more 

 than one-quarter inch. 



The \]/i inch x 22-inch air hose is used with an automatic con- 

 nector of the general appearance shown below : 



Data sheet "A" shows the number of hose lengths removed 

 for all causes during the year from November, 1911, to Novem- 

 ber, 1912, this being classified under (1) the general causes for 

 removal, and (2) the life. The total number of hose pur- 

 chased of each make for a period of three years is also shown 

 as an indication of tlie proportion of the different makes of hose 



7 N»PP L 



