GMW17540

Description / Abstract: GMW17540, 1st Edition, April 2018 - Fuel and Oil Resistant Coupled Hose Assembly Braid Reinforced - Polytetrafluoroethylene

Material Description.

This specification covers coupled hose for use with gasoline, oil, and diesel fuel and related evaporative systems. These hose assemblies, Type I and Type II, are suitable for use at temperatures of -40 °C to +230 °C and operating pressures to 1.75 MPa. If no type is specified on drawing, it shall be assumed to be Type I. All testing parameters shall apply to both Type I and Type II unless specified.

a. Type I: Stainless Steel Reinforcement

b. Type II: Glass Fiber Reinforcement

Hose Construction.

Type I.

The hose shall consist of an inner hose of virgin polytetrafluoroethylene (PTFE) reinforced with a stainless steel wire braid covering.

Inner Hose. The inner hose shall be a black, conductive smoothbore seamless hose of polytetrafluorethylene (PTFE) resin conforming to the requirements of virgin Type I Grade 4 Class B resin per ASTM D4895. The inner surface of the hose shall have conductive properties.

Wire Braid Reinforcement. The reinforcement shall consist of 0.20 mm to 0.40 mm diameter AISI Type 302, Type 304, or Type 316 stainless steel wire applied with a weaving construction of two over and two under such that a minimum 90% coverage is achieved, when using ANSI/SCTE 51 2012.

Quick Connectors. Quick connectors used in Fuel and Oil Resistant Coupled Hose Assemblies released to the GMW17540 specification shall meet the requirements of GMW17568.

Type II.

The hose shall consist of an inner hose of virgin PTFE reinforced with electrical grade continuous filament glass fibers and aramid fibers.

Inner Hose. The inner hose shall be black, conductive smoothbore seamless hose of PTFE resin conforming to the requirements of virgin Type I Grade 4 Class B resin per ASTM D4895.

Fiber Reinforcement. The reinforcement shall consist of (78 to 90)% electrical grade continuous filament glass fibers blended with (10 to 22)% aramid fibers having minimum 9000 yarn denier for 7.94 mm (5/16 in) or less nominal inside diameter hose, 14 000 yarn denier for 9.53 mm (3/8 in) or greater nominal inside diameter hose, and 14 000 yarn denier for 12.70 mm (1/2 in) hose bonded to the hose by means of a Teflon coating with a weaving construction of two over and two under such that a minimum 90% coverage is achieved. Coating pigment shall be black. No glues or adhesives are permissible. The braid is bonded to the hose with a PTFE emulsion.

Coupling Construction.

The coupling shall be designed, inserted, and swaged or crimped so that no internal PTFE hose abrasions, cuts, or flaws shall result under any condition or combination of assembly component dimensioning or tolerancing allowed by supplier production specifications or under any condition of hose compression allowed by supplier production specification.

Sharp corners shall be avoided where the coupling contacts the hose to prevent cutting of the hose when subjected to internal pressure.

Hose Insert. The end of the hose insert must be radiused to eliminate burrs or sharp edges which might cause PTFE hose damage under conditions of assembly vibration or pressure impulse.

Damage. Damage to PTFE hose or reinforcement generated by the crimping of the hose is not permissible under any possible production manufacturing conditions or supplier production tolerance stack-up, including variations in hose compression concentricity.

Hose Collapse. Metal hose insert collapse during crimping is not permissible, except when this collapse is limited, predictable, controllable, and does not increase the potential for assembly leakage or other malfunction.

Design Restrictions. Grooves, upsets, or serrations are not permitted on the hose stem OD, or on the crimp shell ID, except that these grooves, upsets, or serrations do not cause PTFE hose cutting or other damage under any condition or combination of assembly component dimensioning or tolerancing allowed by supplier production specifications, or under any condition of PTFE hose compression allowed by supplier production specifications.

Adhesives. Use of adhesives in the crimped joint is not permissible.

Flow Requirements. The coupling shall be designed for low flow restriction.

Dimensions and Tolerances. Hose furnished to this specification shall conform to the dimensions and tolerances shown in Table 1 for the size (nominal inside diameter) specified by the purchaser. Supplier should demonstrate capability to three (3) sigma CPk of 1.33.

Material Identification. To properly define the assembly, the assembly specification number is to be followed by a Type (e.g., GMW17540 Type II). Drawing Callouts not referencing an assembly "Type" are assumed to be referencing Type I.

Hose Marking. The hose assembly shall be legibly identified with the manufacturer's name or trademark and date of manufacture. 1.2

Symbols. Not applicable.

Applicability. This specification covers coupled hose for use with gasoline, oil, and diesel fuel and related evaporative systems.