Rupture disk/pressure-relief valves combination

Sizing, 451, 453, 455, 459, 462 Sonic flow, 461 Types, illustrations, 411-421 Rupture disk, liquids, 462, 466 Rupture disk/pressure-relief valves combination, 463 Safely relief valve, 400 See Relief valve Safety valve, 400, 434 Safety, vacuum, 343 Scale-up, mixing, 312, 314—316 Design procedure, 316-318 Schedules/summaries Equipment, 30, 31 Lines, 23, 24 Screen particle size, 225 Scrubber, spray, 269, 270 Impingement, 269, 272 Separator applications, liquid particles, 235 Liquid particles, 235 Separator selection, 224, 225 Comparison chart, 230 Efficiency, 231... 

Breaking pin device in combination with pressure relief valve. This style of pressure relief device, as illustrated in Fig. 8-19, is very similar to the rupture disk and relief valve combination, except that a breaking pin is used in place of the rupture disk. The breaking pin device is a nonreclosing pressure relief device actuated by inlet static pressure and is designed to function by the breaking of the load carrying section of the pin. 

Rupture disk device in combination with pressure relief valve. Combination rupture disk/pressure relief devices, as illustrated in Fig. 8-18, consist of a conventional reclosing pressure relief valve in series with a rupture disk. The rupture disk is located between the pressure relief valve and the container. The relief valve is... 

When this combination-type pressure relief device is installed, some regulations require that the space between the rupture disk and relief valve be vented to the atmosphere or monitored to detect any pressure buildup on the downstream side of the rupture disk, which could prevent proper functioning of the rupture disk. 

Typical rupture disk assembly installed in combination with a pressure relief valve... 

V Tiere the pressure relief valve is used in series with a rupture disk, a combination capacity of 0.8 must be applied to the denominator of the referenced equations. Refer to a later section this text or to specific manufacturers. 

When the rupture disk is installed on the inlet side of the pressure relief valve (see Figures 7-10, 7-11 and 7-12), the ASME code requires that for untested disk-valve combinations that the relieving capacity of the combination be reduced to 80% of the rated relieving capacity of the pressure relief valve [ 1 ]. 

For flow tested combinations, see a few typical data in Table 7-12. Note, for example, that using a Continental disk reverse acting knife blade rupture disc with a Crosby JOS/JBS pressure relief valve that the combined effect is to multiply the rated capacity of the Crosby valve by a multiplier of 0.985 for a set pressure in the 60-74 psig range... 

Sizing for Combination of Rupture Disk and Pressure Relief Valve in Series Combination... 

Type CG-8, This is a combination device consisting of a rupture disk device followed by and in series with a pressure relief valve. The piping connecting the rupture disk and pressure relief valve is equipped with a sensing device to indicate pressure. The system is designed and constructed so the required relieving capacity is achieved and the operation of the relief valve is not impeded. 

Fig. 8-18. Rupture disk device (Type CG-1) in combination with pressure relief valve (Type CG-7) for cargo tanks.

Pressure relief devices authorized for use on argon cylinders are the Type CG-1 rupture disk, CG-4 and CG-5 combination rupture disk/fusible plug devices, and the CG-7 pressure relief valve. Refer to CGA S-1.1, Pressure Relief Device Standards—Part I— Cylinders for Compressed Gases, for further information. [4]... 

Carbon tetrafluoride is authorized for shipment in DOT specified cylinders as identified in 49 CFR 173.302 and equivalent Canadian regulations. [1] and [2] Authorized pressure relief devices include the Type CG-1 rupture disk, the Type CG-4 or CG-5 combination rupture disk/fusible plug device, or the Type CG-7 pressure relief valve. [3] The rupture disk must have a bursting pressure not exceeding the minimum prescribed test pressure of the cylinder. 

CG-4 Combination rupture disk with 165 F (73.9°C) Fusible alloy backing CG-5 Combination rupture disk with 212 F (100°C) Fusible alloy backing CG-7 Pressure relief valve... 

Pressure relief devices authorized for use on helium cylinders include the CG-1, CG-4, CG-5, and CG-7 type devices. These include rupture disk, combination rupture disk/fus-ible plug, and pressure relief valve type devices. For further information and requirements, see CGA S-1.1, Pressure Relief... 

The relief capacity of the rupture disks should be at least equal to the combined capacity of the pressurizer relief valves and safety valves with sufficient allowance. 

Rupture Disks A rupture disk is a device designed to function by the bursting of a pressure-retaining disk (Fig. 26-15). This assembly consists of a thin, circular membrane usually made of metal, plastic, or graphite that is firmly clamped in a disk holder. When the process reaches the bursting pressure of the disk, the disk ruptures and releases the pressure. Rupture disks can be installed alone or in combination with other types of devices. Once blown, rupture disks do not reseat thus, the entire contents of the upstream process equipment will be vented. Rupture disks are commonly used in series (upstream) with a relief valve to prevent corrosive fluids from contacting the metal parts of the valve. In addition, this combination is a reclosing system. 

The capacity of the combination of the rupture disk device and the spring loaded safety or safety relief v alve may be established in accordance with the appropriate paragraphs of UG-132, Certification of Capacity of Safety Relief Valves in Combination with Non-reclosing Pressure Relief Devices. 

For preliminary estimates, the coefficient Kj can be taken as 0.975 for a relief valve and 0.62 for a bursting disk. The back-pressure correction factor, Ky, can initially be assumed to be 1.0 for critical flow. The combination correction factor, K, is used when a rupture disk is used upstream of the relief valve (see next section), in which case it is 0.9. If no rupture disk is used, then is 1.0. For vessels designed in accordance with AS ME BPV Code Sec. VIII, Pj = 1.1 times the maximum allowable working pressure. 

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