Installation rupture discs

Typical stand-alone rupture disc installation... 

Figure 6-14 Proper installations of a pre-bulged rupture disc and reverse buckling rupture disc installation. Courtesy of Jim C. Burns, Oklahoma Safety Equipment Company.

An important application of a rupture disc device is at the inlet of a pressure relief valve. The sizing of the pressure relief valve or rupture disc device combination requires that the pressure relief valve first be sized to meet the required relieving capacity. The normal size of the rupture disc device installed at the inlet of the pressure relief valve must be equal to or greater than the nominal size of the inlet connection of the valve to permit sufficient flow capacity and valve performance. The failure modes of rupture discs are [40] ... 

The best way to prevent accidents such as this is to use rupture discs, which are harder to assemble incorrectly and which can be checked for correct installation after assembly. It is possible to get discs permanently attached to their vacuum supports by the manufacturer and fitted with a projecting tag, which carries the words vent side on one side. The tag also gives the pressure rating. 

The client insisted on a test. The smoke detectors worked, and the explosive charge operated, but the cutter did not cut the rupture disc. The explosive charge could not develop enough pressure because the volume between it and the rupture disc was too great. The volume had been increased as the result of a change in design installation of a device for discharging the halon manually. 

Have rupture discs been inspected (for having blown) as scheduled Yes. Though none have failed, procedure calls for inspection of rupture disc and installation after maintenance. 

When rupture discs are used before a spring-loaded relief, a pressure gauge is installed between the two devices. This telltale gauge is an indicator that shows when the disc ruptures. The failure can be the result of a pressure excursion or of a pinhole caused by corrosion. In either case the telltale gauge indicates that the disc needs to be replaced. 

Burst Diqphragm or Burst Disc(Blowout Diaphragm or Rupture Disc). A flat circular sheet of frangible material (plastic or metal) installed across the pipe suppling liquid propellant to the thrust chamber of a rocket. The purpose of the disc is to prevent flow of liquid until proplnt pressure builds to a preselected value. The disc then shears open and the proplnt is released to flow... 

Rupture discs can also be used in pairs or in parallel with an SRV for additional safety, operational and installation cost benefits and system integrity. 

It is equally recommended that a pressure gauge between rupture disc and SRV be installed, functioning as a burst indicator... 

No risk if product is lost after a pressure upset Rupture discs are nonreclosing devices. Whatever is in the system will get out and continue to do so until it is stopped by some form of intervention. If loss of contents is not an issue and it is installed as such, that action can be prompted. 

Also, for new installations each installed rupture disc must be purchased along with a disc holder. This holder basically consists of two flanges between which the rupture disc is held. Disc holders are typical for specific manufacturers and are not interchangeable. The same holder may only be used for replacement purchases as long as you buy the exact same rupture disc from the same manufacturer. So the disc type and holder are pretty much a set. 

Safety valves shall be totally enclosed and shall not discharge to the atmosphere, except through an escape pipe that will carry such vapours to a safe point of discharge outside of the building. The safety valve shall not have a lifting lever and valve body drains are not mandatory. A rupture disc may be installed between the safety valve and the vaporizer. The required minimum safety valve-relieving capacity shall be determined from the formula ... 

When combining two relief devices, they can be used after each other or in parallel. When used in parallel, for whatever reason, there is no need for a derating. However, the rated relieving capacity of an SRV in combination with a rupture disc is equal to the capacity of the PRV multiplied by a combination capacity factor to account for any flow losses attributed to the rupture disc which might depend on the type of installation. 

Kc is the combination correction factor if a rupture disc is installed upstream of the SRV (if there is no rupture disc, Kc = 1). 

API RP 520 Part II and ASME VIII Division 1 contain numerous other installation requirements. This category represents all other installation deficiencies that were identified for both relief valves and rupture discs. 

Overpressure accidents can not only damage equipment but also cause injury or even death to plant personnel. In order to reduce the potential number of incidents or accidents, it is the job of the process engineer to analyse the process design and to determine the what can go wrong scenarios and either find a way to design out of them or provide protection against catastrophic failure in the event an accident does occur, that is, install an SRV and/or rupture disc. 

Pipefitters have occasionally installed reverse buckling rupture discs upside down. Depending on the rupture disc manufacturer specifications, this usually means that the bursting pressure of the disc will be 50 percent higher than the manufacturer guaranteed as the relieving pressure. Such incidents must have happened at numerous plants and have been whispered about, but seldom documented. 

The simple error of installing a rupture disc upside down is easy to do in a minute or two and can jeopardize the integrity of the overpressure protection system. Rupture disk manufacturer s representatives are available to discuss proper rupture disk handling with engineers and craftsman. Such training can be very helpful. 

Active A reaction capable of generating 22 kPa, realized in a reactor with a 1 kPa high-pressure interlock to stop reactant feeds and a properly sized 3 kPa rupture disc discharging to an effluent treatment system The interlock could fail to stop the reaction in time, and the rupture disk could be plugged or improperly installed, resulting in reactor failure in case of a runaway reaction. The effluent treatment system could fail to prevent a hazardous release... 

Corrosive fluids are less likely candidates for the use of pressure relief valves. Whether by corrosion of the valve itself or of surrounding pipework, they often create a problem with deposits on the valve element or its seat. These deposits can prevent proper sealing and allow the slow escape of fluid. To combine the advantages of rupture discs and relief valves, the two devices can be installed in series, with the disc before the valve. Even if the valve is not precisely seated, there is no release from the system until the disc bursts. The same overpressure then also opens the valve. Once the piessme has dissipated and dropped below its set point, the valve reseats and prevents further release. 

There are two kinds of chamber, lype A is recommended for continuous supply pipelines and should be installed at the high point of a system. The rupture disc is set for about 2,750 kPa, and it can be changed without shutdown of the pipeline supply. The secondary chamber in such a case must be purged of chlorine and evacuated. The primary chamber can be emptied of chlorine by displacement with dry air or nitrogen. This should be done periodically as needed the same is true of a Type B chamber. 

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