June 1. 1921 



THE INDIA RUBBER WORLD 



639 



VULCANIZING EFFECT 



Antimony sulphurct of itself is not a vulcanizing agent but 

 any effect produced on the physical properties of rubber cured 

 with it IS due entirely to the free sulphur which the sulphuret 

 contains. While true, this observation has often been miscon- 

 strued and the idea conveyed that aside from the coloring prop- 

 erties of the antimony sulphides, there art no properties whicli 

 advantageously effect the vulcanization of rubber. 



Investigation has shown that although antimony sulphides 

 alor.e will not vulcanize rubber, they will, wh-jn incorporated in 

 a rubber-sulphur mixing, produce a ma.ximum tensile strength 

 in a shorter time and with a lower proportion of free sulphur to 

 rubber than it is possible to obtain when an inert filler is use<l 

 instead of the antimony sulphides or when a simple rubber and 

 sulphur mixture is employed. It has been demonstrated that in 

 this accelerating action the pentasulphide is more efficient than the 

 trisulphide and that the acceleration of cure is not due to the 

 colloidal nature of the free sulphur contained in the pentasulphide. 



The use of commercial flour sulphur with antimony penta- 

 sulphide gives results at least equal to those obtained by the 

 use of colloidal sulphur coprecipitated with antimony penta- 

 sulphide. 



AMERICAN RAILWAY ASSOCIATION, MECHANICAL 



DIVISION. MASTER CAR BUILDERS' AND 



MASTER MECHANICS' SPECIFICATIONS. 



STANDARD STEAM-HEAT HOSE 



Adopted, 1916; Revised, 1917 



I. MANUFACTURE 



1. Scope. These specifications cover steam-heat hose for pas- 

 senger equipment cars. 



2. Steam-heat hose shall be composed of a tube of rubber, 

 wrapped with at least five plies of cotton fabric and the whole 

 covered with rubber. 



II. PHYSICAL PROPERTIES AND TESTS 



3. The railway company's inspector will select for test one 

 piece at random from each lot of 201 pieces. When this hose is 

 received at tlie test laboratory, a section 2J4 inches long will be 

 cut from one end in order to determine the friction, tensile 

 strength and elongation. The remaining portion will then be sub- 

 jected to steam heat in the digester. After this section has been 

 heated another section Z'/i inches long will be cut from it and 

 used to ascertain the friction, tensile strength and elongation, in 

 order to show the change in these characteristics due to the 

 action of heat. 



4. Friction Test Before Steaming. A section 1 inch long 

 will be cut from the hose and supported in such a manner that 

 it will turn freely on its axis. A 20-pound weight will be sus- 

 pended from the separated end of the fabric. The latter must 

 unwind uniformly, if at all, ami not faster than 6 inches in ten 

 minutes. 



5. Tensile Test Before .Steaming. A strip cut from the tube 

 with a die or other suitable means to the dimensions shown in 

 Fig. 1 will be marked at points 2 inches apart, and the width and 

 thickness will be accurately measured. It will then be slowly 

 stretched in a suitable tensile-testing machine until it breaks. The 

 ultimate tensile strength must not be less than 600 pounds Jicr 

 square inch and the elongation of the 2-inch section at the time 

 of fracture must be not less than 6 inches. 



6. Friction Test After Ste-^ming. A section 1 inch long 

 will be supported in such a manner that it will turn freely on its 

 axis. A i.S-pound weight will be suspended from the sc|iarated 

 end of the fabric. The latter must unwind uniformly, if at all, 

 and not faster than 6 inches in ten minutes. 



7. Tensile Test After Steaming. A strip cut from the tube 

 with a die or other suitable means to the dimensions shown in 

 Fig. 1 will be marked at points 2 inches apart, and tlie width and 

 thickness will be accuratclv measured. It will then he slowly 

 stretched in a suitable tensilc-tcstnig machine until if breaks. The 

 ultimate tensile strength must not be less than 4,S0 pounds ner 

 square inch, and the elongation of the 2-inch section at the time 

 of fracture must not be more tha^i 8 inches or less than 4 inches. 



8. Digester Test. Tlie digester shall consist of a cylinder 

 containing dry saturated steam at a pressure of 45 pounds per 



square inch. The hose shall be put into this digester and will 

 remain there for 48 hours continuously. An examination of this 

 section, after being submitted to the heat of the steam, should 

 not disclose any blistering of the inner tube or any loosening of the 



Fig. 1. Tensile Specimen 



tube from the fabric. Examination and test after heating, pre- 

 scribed in the specifications, will be made as soon as possible after 

 the specimen has cooled for 24 hours. The tests will be made 

 at a temperature of not less than 60 degrees F. 



in. SIZE AND DIMENSIONS 



Length 



Inner di.imeter . . . . 

 Outer diameter . . . . 

 Thickness of tube 

 Thickness of cover 



Maximum Minimum 

 Inches Inches 



2414 23M 





IV. WORKMANSHIP 



9. Tube. The tube should be composed of at least two calen- 

 ders of rubber. It must be free from holes, bits of wood, bark, 

 sand and other foreign matter, and from other imperfections. It 

 must be so firmly joined to the fabric that it can not be pulled 

 off without tearing it. 



10. F.VBRic. The fabric must be of duck, with the warp con- 

 taining not less than 27 strands, 3 threads per strand, and the filler 

 18 strands and 4 threads per strand. It must be frictioned on both 

 sides and have, in addition, a distinct layer of rubber on one side, 

 readily visible between the plies when the finished hose is cut 

 open. 



11. Cover. The material of the cover should be a rubber com- 

 pound which has good weather-resisting qualities, as firmly 

 attached to the fabric as is the tube, and to be equally free from 

 defects. The end of the hose should be cut ofif true to length, but 

 shall not be capped. 



V. MARKING 



12. Serial Number. Each lot of 200 hose or less must bear 

 the manufacturer's serial number, beginning with one on the first 

 of each year and continuing consecutively until the end of the 

 year. Serial numbers of hose which are rejected must not be used 

 again. With each lot of 200 hose or less, one extra piece of hose 

 must be furnished free of cost. 



13. Label. Each piece of hose must have securely vulcanized 

 to it a label of white or red rubber, as shown herewith. 



A.B.C. ROAD -STEAM 



NAME OF MANUFACTURER 



11—6 —\\ 

 SERIAL NUMBER 



Fig. 2. Label 



VI. inspection 



14. Inspection. If the sample passes all the tests, all pieces 

 represented by it will be accepted if free from injurious mechan- 

 ical defects. 



Rejected hose will be returned at the expense of the manu- 

 facturer. 



15. Rejection. If the sample fails to pass the above tests, the 

 lot represented by it will be rejected and the same serial number 

 must not be applied to any other steam hose during the same 

 calendar year. 



16. Rehearsing. Samples tested in accordance with these spec- 

 ifications, which represent rejected hose, shall be held for two 

 weeks from date of test report. 



