Rupture disk pressure relief valve

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... 

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. 

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. 

Man Cognitive function (observation) Observation missed Second operator did not observe closed status of isolation valve and closed block valve, isolating the ammonia pressure control valve from the heat exchange. Afterwards, he started to steam the process line to clean the pipeline. The closed isolation and block valves prevented the increasing ammonia pressure from safely venting through either the ammonia pressure control valve or the rupture disk and relief valve. 

In the fifth layer of protection, passive rehef devices, such as rupture disks and relief valves, provide physical protection by preventing excessive pressures from being generated within process vessels and pipelines. If over-pressurization occurs, the relief valve or rupture disk opens and the fluid is vented to an appropriate location, such as a combustion flare stack, incinerator, scrubber, waste treatment faciUty, or the atmosphere. Such passive devices operate independently of the SIS system. 

If a rupture disk is installed to isolate the relief valve from a particularly corrosive process, and the integrity of the mpture disk is known to be good, the interval between inspections may be increased. The rupture disk integrity must be verified via checks for pressure between the rupture disk and relief valve. 

One potential problem with the use of rupture disks below relief valves concerns the possibility of pinhole leaks in the rupture disk. If such a leak occurs, then the pressure on the downstream side of the disk will be roughly equal to the process pressure. Therefore, the absolute process pressme required to rupture the disk may be almost twice as high as expected. Moreover, the existence of the pinhole leak may lead to the development of the problem that it was intended to avert, e.g., the relief valve could be plugged with polymer without anyone being aware of the situation. Because of the dangers associated with pinhole leaks, it is good practice to install a pressure gage in the spool piece between the rupture disk and the relief valve. 

FIG. 26 13 Typical pressure relief system configurations (a) rupture disk system (h) pressure relief valve system. 

An important case of gas discliarge is tlie flow from pressure relief valves and rupture disks. Wlien relief is required due to fire exposure in a nonreacting... 

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. 

To pro dde some external protection against the damage that an external lire can do to a pressure relief valve or rupture disk, this author recommends that these devices be insulated after installation in such a manner as not to restrict their action but to provide some measure of reliable performance, even if the vessel is not insulated. 

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

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... 

For a flare stack to function properly and to handle the capacity that may be required, the flows under emergency conditions from each of the potential sources must be carefully evaluated. These include, but may not be limited to, pressure relief valves and rupture disks, process blowdown for startup, shutdown, upset conditions, and plant... 

Carbon dioxide is usually purchased in a tank, inside the tank the mobile phase exists as a liquid. Typically, the tank does not come with a pressure gauge but is hooked up to a pressure relief valve and rupture disk, which are set above the tank pressure should a tank leak occur. 

Tanks with vent hlters must be designed for pressures of -20 kPa and +100 kPa and must be equipped with a rupture disk. Tanks for hot loop and steam sterilizable line must be designed to withstand steam sterilization (121°C). A steam jacketed sterile vent hlter must be used to avoid condensation in the hlter and the vent hlter housing temperature controlled. The tank for hot storage is steam jacketed and insulated for temperature maintenance. Minimum instrumentation shall include level indication, temperature recording controller, pressure gauge, and pressure relief valve. 

A rupture disk is a thin sheet of metal installed below the valve, intended to protect the relief valve from plugging. The rupture disk ruptures at the relief-valve-set pressure. A better approach to retard this plugging problem is to maintain a steam purge, or inert-gas bleed, below the relief valve to prevent the accumulation of solids below the valve. 

Another feature of PD pumps is that, if the line for any reason becomes blocked, they simply continue forcing high-pressure fluid into the line and eventually break something if a precautionary rupture system has not been installed. Thus, a PD pump should be protected by a high-pressure shutoff sensor and alarm system and also a bypass line containing a rupture disk or pressure relief valve. 

Both rupture disks and breaking-pin devices are sensitive to temperature. The manufacturer should always be consulted for applications that are not at ambient conditions. Since non-reclosing pressure-relief devices can be used only once, the set pressure is determined by testing a sample of the devices out of each manufactured batch. Pressure-relief valve test methods are specified in AS ME PTC 25-2001. 

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