Pressure relief devices rupture disk device combined with fusible plug

As previously stated, the valve must be equipped with a Type CG-1 pressure relief device equipped with a rupture disk. A backed pressure relief device, that is, a combination rupture disk/fusible plug device, must not be used on a carbon dioxide cylinder valve. 

The most common cylinder valve used for dichlorosilane is a stainless steel diaphragm valve with a Connection CGA 678 outlet. The cylinder valve body has a combination CG-4 type pressure relief device consisting of a fusible metal plug, melting about 165°F (74°C), which is protected from the cylinder contents by a frangible metal disk, i.e. a rupture disk, rated at 250 psig (1724 kPa). 

Pressure relief devices authorized for use on hydrogen cylinders include the CG-1 rupture disk, CG-4 and CG-5 combination rupture disk/fusible plug devices, and the CG-7 pressure relief valve, in accordance with requirements given in CGA S-1.1, Pressure Relief Device Standards—Part 1—Cylinders for Compressed Gases, [12]... 

Cylinders must be equipped with a CG-4 type pressure relief device. This device must be in both ends of the cylinder when the cylinder is over 30 inches (76 cm) in length. This type of device is a combination rupture disk/ fusible plug, utilizing a fusible alloy with a yield temperature not over I70°F (76.7°C). 

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See also in sourсe #XX -- [ ]

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