September 1, 1920. 



THE INDIA RUBBER WORLD 



807 



{,d) Over the rubber cover for a distance of six inches from 

 each end there shall be vulcanized a strip of duck same as that 

 used in canvas layers. 



(<•) Dimensions.— See the following table. 



Br.\ndinc.— See General Specifications. 



(a) Use words "Dredging Sleeves." 



Material. — Sec General Specifications. 



(a) Cotton canvas layers shall be made from duck weighing 

 not less ihan 30 ounces per square yard and containing not less 

 than 13 nor more than 20 yarns per inch each in warp and filling. 



Inspection. — See General Specifications. 



(a) With each lot of 10 sleeves or less the manufacturer shall 

 provide the inspector for test a sample I'/i inches wide of same 

 material and construction, made up with the sleeve, at one end, 

 but detached so as not to impair the finished sleeve. Manufac- 

 turer shall submit one lineal foot of unfrictioned duck with each 

 order. 



(b) If samples corresponding to any one lot of sleeves fail 

 to meet the tests, the contracting officer may reject the lot or 

 may, with the consent of the contractor, accept part or all of it 

 at not more than 75 per cent of the contract price, provided, how- 

 ever, that it does not fall below by more than 10 per cent of the 

 test. 



Tests. — See General Specifications and following table, 

 (o) Test specimens of tube shall be buffed down to approxi- 

 mately ^-inch. 



Table. 



RED SHEET PACKING. 



War Department SpeciScation, No. 333-2-3 — June 6. 1919. 

 (Ai-THORiTY or SippLV CiKCLLAR Xo. 8, P. S. & T. Div., January 24, 1919.) 



General. — (a) This specification covers the requirements for 

 red sheet packing to be used in joints in connection with cold 

 water, hot water, and steam up to and including 150 pounds 

 pressure. 



(b) See War Department Specification No. 333-1-1, headed 

 General Specification for Mechanical Rubber Goods', which is 

 made a part hereof, except in such cases as the provisions below 

 directly conflict. In such cases the word and meaning of this 

 specification will govern. 



Construction. — See General Specifications. 



(a) Packing shall be in rolls about 36 inches wide, approxi- 

 mately 125 pounds in weight and of thickness specified. 



Branding. — -See General Specifications. 



(a) Use the words "Red Sheet." 



Materials. — See General Specifications. 



(a) Packing shall be of a specific gravity not less than 1.8 nor 

 more than 2.2, which is equivalent to not less than 2.65 pounds 

 nor more than 3.23 pounds per square yard for each 1/32-inch 

 of thickness. 



Inspection. — See General Specifications. 



Tests.— See General Specifications, 



(a) Tensile specimens may be taken in any direction. 



(b) Tensile strength, minimum, SCO pounds. 

 Ultimate elongation, minimum, two to four inches. 

 Ultimate elongation, maximum, two to seven inches. 



(c) Packing shall not crack when bent double in any direction, 

 (rf) .\ section of packing shall he cut in the form of a gasket 



such that it will entirely cover the seat of a 2-iiirh fiance of an 

 autoclave. A steel plate the size of the flange shall then be 

 securely clamped over the gasket. It shall then be exposed to 

 a steam pressure of ?.50 pounds per square inch for four hours. 



-After the sample has been removed from the flange of the 

 autoclave it shall be allowed to cool for one hour, after which 

 packing under 1/8-inch thick shall not crack if bent double in 

 any direction and packing 1/8-inch and over in thickness shall 

 not crack if bent around a 1/2-inch round mandrel. 



TUCK'S PACKING. 



War Department SpeciSoation, No. 833-2-4 — June 5, 1919. 

 (AuTKORiTv OF SuppLY CiRCfi-AR No. S, P. S.&T. I)iv., Jani;ary 24, 1919.) 



General.— (a) This packing is to be used as stuffing-box 

 1)acking on pistons in pumps and engines. 



(6) See War Department Specification No. 333-1-1, headed 

 General Specification for Mechanical Rubber Goods', which is 

 made a part hereof, except in such cases as the provisions below 

 directly conflict. In such cases the word and meaning of this 

 specilication will govern. 



CoNSTRUCTio.N'. — See General Specifications. 



(o) Tuck's packing shall consist of frictioned cotton canvas 

 layers either round or square, as specified. The round packing 

 shall be made with a rubber core, unless otherwise specified. 



(b) It shall be built up on the bias and shall conform in 

 dimensions, plies, and textures to the following table: 



Texture of plies. 



Number of pli( 



ing friction 



to 17. 



(c) The rubber core shall have a diameter equal to one-third 

 the diameter of packing. 

 Branding. — Not required. 

 Materials. — See General Specifications. 



(a) The rubber core shall contain not less than 35 per cent 

 fine Para rubber ; not more than three per cent sulphur, and 

 the remainder shall consist of suitable drv inorganic mineral 

 fillers. 



(b) Friction shall be of such a com[wund as to meet required 

 tests. 



Inspection. — See General Specifications. 



(o) A section six inches long shall be cut from any length at 

 any place to allow for four or more tests. 

 Tests. — See General Specifications. 



(a) The completed article shall withstand boiling in water 

 under 80 pounds' steam pressure for four hours without loosen- 

 ing tile fric'ion or materially hardening the rubber. 



(b) Packing shall be sufficiently flexible to admit of bending 

 easily around rods or pistons of various sizes. The 1/4 to 3/4- 

 inch shall bend around its diameter, the 7/8 to 1 1/8-inch around 

 twice its diameter, and the larger sizes around three times their 

 diameter. 



(c) Friction shall be such that a weight of 8 pounds shall not 

 cause a separation greater than 1 inch per minute, calculated 

 upon a basis of a 1-inch specimen. 



(rf) Tensile strength of the rubber core shall be at least 900 

 pounds per square inch, and it shall have an elongation at the 

 breaking point of at least two to eight inches. 



DIAPHRAGM PACKING. 



War Department Specification, No. 333-2-2 — June 6, 1919. 



(.\L-TnORITY OF SuPPLV ClRCLI.AR \o. S, P. S. & T. DiV., JaNI'ARY 24, 1919.) 



General. — (a) This packing is to be used for making dia- 

 phragms for diaphragm pumps. 



(b) See War Department Specification No. 333-1-1, headed 

 General Specification for Mechanical Rubber Goods', which is 

 made a part hereof, except in such cases as the provisions below 

 directly conflict. In such cases the word and meaning of this 

 specification will govern. 



Con'struction. — See General Specifications. 



(a) The packing shall be in sheets approximately 36 inches 

 wide and made into rolls of about 125 pounds each. It shall be 

 constructed of two layers of cotton fabric using a layer of ruober 

 between them and a layer of rubber on each side, making alter- 

 nate layers of rubber and fabric. 



The rubber layer which separates the plies of duck shall be 

 1/16-inch thick. The outer rubber layers shall be equal in thick- 

 ness, but of such a thickness to make the total thickness of the 

 packing 1/4-inch. 



(b) The cotton canvas plies shall be frictioned on both sides 

 with the same qualify material as used in the rubber compound 

 and shall withstand the friction test mentioned below. 



Branding. — See General Specifications, 

 (a) Use the word "Diaphragm." 



•See The India Rubber World. January 



1920, 



214. 



