Frangible disk

Figure 7-8A. Metal type frangible disk (above) with cross-section (below) Courtesy of Black, Sivalls and Bryson Safety Systems, Inc.

Figure 7-9A. Non-metal frangible disk. Ruptured disk showing complete breakout of membrane. Courtesy of Falls industries, Inc.

Figure 7-9B. Standard non-metal frangible disk (graphite). Teflon coatings or linings are avaiiable on entire disk. By permission, Zook Enterprises.

Fio. 14r3. Safety diaphragm (frangible disk) for the relief of excessive autoclave pressures (a) Before bursting and (h) After bursting. 

Nitrogen dioxide is also authorized for shipment in Specification 106A500X TMU containers and 105A500W tank cars, the latter of which are equipped with a combination pressure relief valve including a stainless steel or platinum frangible disk. Specification 110A500W tank cars are also authorized. See 49 CFR 173.336 [9]. 

Note DOT and TC Specification 3A and 3AA steel cylinders having a plus rating ( + after the most recent retest date), which do not contain a pressure relief assembly with a fusible metal-backed frangible disk, may be filled to 110 percent of the marked service pressure, when filled with an atmospheric gas. 

The frangible disk is used mostly on high-pressure cylinders. This disk will burst, releasing the entire contents of the cylinder, at a pressure above the service pressure and above the hydrostatic test pressure of the cylinder. 

The frangible disk backed up by fusible metal will burst only if the temperature of the fusible metal s melting point has been exceeded and there is also excessive pressure in the cylinder. This occurrence will also release the entire contents of the cylinder. 

Frangible disk/fusible metal. This device functions only after sufficient heat has melted the fusible disk, after which excessive pressure will burst the frangible disk. The entire contents of the cylinder will then escape. 

Frangible disk. This is commonly used in most high-pressure cylinders. The disk will burst at a pressure considerably higher than the service pressure of a cylinder, but before the cylinder s hydrostatic test pressure limit is reached. Once again, all the cylinder contents will escape. 

Some vessels may be exposed to a runaway chemical reaction or even an explosion. This requires rehef valves, rupture disks, or, in extreme cases, a frangible roofdesign or barricade (the vessel is expendable). A vessel with a large rupture disk needs anchors designed for the jet thrust when the disk blows. 

When using safety valves to relieve pressure vessels, consider isolating them from the process by using rupture disks (frangible safeties). There are several reasons for this. 

The most visible component of a sprinkler system is the sprinkler head. A sprinkler head consists of a deflector, which looks like a round disk with teeth cut out into it. The deflector is supported by two frame arms that run between the deflector and the threaded base, which is screwed into the sprinkler system piping. To keep the water from escaping, an orifice cap, which acts much like a cork in a bottle, is held in place by a thermally activated releasing mechanism. There are two systems of thermally activated releasing mechanisms used for this purpose. The first is a frangible bulb, which will appear like a small glass tube filled with a colored liquid, in the center of the sprinkler head. The color of the liquid indicates... 

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). 

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