MIL-STD-1411B
Prior to examination, cylinders undergoing UE shall be shot-blasted as necessary to insure proper acoustic coupling between the ultrasonic transducers and the cylinder wall. After successfully qualifying to return to service, these cylinders shall be repainted in accordance with MIL-STD-101 and the specific PID, and inspected in accordance with this paragraph.
5.2.2.2 Valve protection cap inspection. Each valve protection cap shall be inspected for cracks, dents, or a mismatch in size. Caps with internal threads that are stripped or damaged, making hand mounting on the cylinder impractical after a wire brush removal of rust and corrosion, shall be rejected. Hydrocarbon lubrication is not allowed on cap or flange threads, however, fire resistant fluorocarbon or silicon lubricants are permissible and recommended for cylinders subject to weather or high humidity conditions.
5.2.3 Valves and PRDs. Each valve shall be inspected for damaged hand wheels, bent or leaking stems, and damaged or nicked outlet seats and threads. Further inspection shall be made for dirt, grease, or insect residue. Packing nuts shall be snug to control leakage and bonnet nuts shall be locked tight. Valve inlet threads should expose more than one thread between the cylinder neck and the wrenching boss of the valve. The valve shall be functional and shall control the gas flow at the valve seat when residual gas is checked. Valve outlets shall be in accordance with A-A-59860 as specified in the PID. Damaged or faulty valves shall be scheduled for maintenance or replacement in accordance with A-A-59860.
5.2.3.1 PRDs. PRDs shall be inspected for compliance with CGA S-1.1. Rejected or faulty PRDs shall be scheduled for maintenance or replacement. PRDs that are integral with the cylinder (acetylene or chlorine) shall be inspected for leaks or extruded fusible metal. Faulty devices shall be rejected and scheduled for maintenance or replacement. Fusible plugs integral with a valve body found faulty at inspection shall require valve rejection and shall be scheduled for replacement at maintenance.
5.2.3.1.1 PRD CG-1 (rupture disk). Cylinder valves with CG-1 type PRDs shall be inspected for evidence of leakage and burst limits in accordance with the service pressure identification markings on the cylinder. Faulty disks shall be scheduled for replacement with a manufacturer's complete unit (cap, washer, and disk), as applicable.
5.2.3.1.2 PRD CG-2 and CG-3 (fusible plug). Cylinder valves with CG-2 and CG-3 type PRDs shall be inspected for leakage or extrusion of the fusible metal. Faulty or rejected fusible plugs shall be scheduled for replacement in accordance with the PID (temperature range) and requirements specified in the CGA S-1.1.
5.2.3.1.3 PRD CG-4 and CG-5 (combination rupture disk-fusible plug). Cylinder valves with CG-4 and CG-5 type PRDs shall be inspected for signs of extrusion of the fusible metal at the relief holes. Unstable devices shall be rejected and scheduled for replacement with a new complete PRD CG-4 or CG-5 when required or with the proper PRD CG-1 in accordance with
A-A-59860. Combination PRDs are required by the government for hydrogen, carbon monoxide, sulfur, hexafluoride, and medical gas services. Combination devices are acceptable
in high pressure applications on cylinders with marked service pressures from 1800 psig to 2400 psig. Combination devices are prohibited on cylinders to be filled 10 percent above the marked
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