MIL-S-62127 Semitrailer, Compressed Gas Cylinder: Helium, CommercialThis specification covers a commercial semitrailer for storing, transporting, and charging compressed helium gas. The tandem axle semitrailer mounts 38 cylinders having a combined water capacity of not less than 340 cubic feet and a design working pressure of at least 2400 pounds per square inch gage psig. Semitrailer procured under this specification are commercial items which shall be warranted as specified in the procurement documents.

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MIL-S-62127A(AT)

3.9.4.1 Manifold header. The manifold header shall be fabricated from rigid, seamless pipe or tubing of not less than 3/4-inch inside diameter. Tubing wall thickness shall be sufficient to provide a safety factor of not less than 4 and shall resist damage in normal handling. The manifold header shall be provided with connections for each of the cylinder branch lines,

pressure gage(s), two master flow control and shutoff valves, and two final outlet fittings.

3.9.4.2 Branch. Branch lines between the manifold headers and the individual cylinder valve outlet connections shall be constructed from semiflexible, seamless tubing of sufficient inside diameter for insuring compliance with the flow requirements specified in 3.8.5.6. Tubing wall thickness shall be sufficient to provide a safety factor of not less than 4 and resist damage in normal handling. Each branch line shall be fabricated with a loop or curvature that will insure against placing a strain on the manifold piping in case of relative movement between the cylinders and the manifold assembly.

* 3.9.4.3 Manifold pressure gages. Manifold pressure gage(s) shall be provided for indicating manifold and servicing line pressures. Each pressure gage shall have a dial diameter of not less than 4 inches, shall be graduated over approximately 270 degrees of the dial face, and shall be accurate to within 1 percent of full-scale range. The gage(s) shall have safety backs.

* 3.9.4.3.1 Range. The range of the pressure gages shall be 0 to 5,000 psi. The gages shall be graduated with subdivisions not greater than 25 psi.

* 3.9.4.3.2 Mounting and connections. The pressure gage(s) shall be securely mounted to a panel, frame members, or brackets near the master flow control and shutoff valves in positions readily visible to an operator standing on the ground at the rear of the semitrailer. The pressure gage(s) shall be attached to the manifold pressure sensing connections by means of semiflexible, seamless tubing. The tubing or connections shall not be used for or be a part of the gage mounting. The mounting shall protect the gage(s) against damage during service and road transport, and shall permit removing the gage(s) without disturbing or disconnecting other components.

3.9.4.3.2.1 Connection locations. One pressure sensing connection shall be located in the manifold header between the branch lines and the master flow control and shutoff valves. The other sensing connections shall be located between the master flow control and shutoff valves and the final outlet fittings.