A rupture disk is a kind of device especially made to function by the burst of a pressure-retaining disk. The structure of the rupture disc is simple. It has a thin, circular membrane made from metal, plastic, or graphite which is firmly gripped in a disk holder. When a particular process hits the bursting pressure of the disk, the disk will burst and releases the pressure.
A rupture disk is an independent device that can be installed alone or with a combination of similar types of devices. Once the disc has been blown, the rupture will not reseat, making the entire composition of the upstream process tool will be vented.
This type of device is commonly used in upstream with the use of a relief valve to avoid corrosive fluids from touching the metal parts of the valve. Also, this combination is called a reclosing system. Moreover, the burst tolerance of a rupture disk is basically up to 5% for a set of pressures of less than 40 psig.
The Purpose and Importance of Rupture Disks
A rupture disc is a relief device that is created for rupture at a pre-determined pressure and temperature. It provides security for the personnel and the equipment as well. But for others, it is a fail-safe device. The usage of rupture disks is when a method is full of the opening of pressure relief.
These devices can also be used where “zero” leakage is needed for the relief device. Moreover, these devices can be utilized in a different series like quick opening valves. Also, rupture disks can be both uses in primary and secondary relief in a series of multiple relief valves and other functionality such as quick opening valves.
If the rupture is used for principal relief, the disk is the only device that can be used for the pressure relief. Also, it has different advantages, such as leaking tight, instantaneous responses, lower cost, minimum pressure drop, minimum maintenance, and high reliability.
Like other devices, it has disadvantages too. One of the cons is the disk should be replaced after ruptured and enable venting until the system pressure becomes equal to the downstream demand.
When used to give secondary relief, the rupture disk will provide a backup vent for the primary relief device which is usually the relief valve. Its objective is to provide additional security against the enormous potential event that would exceed the maximum capacity of the primary relief device.
For Series with Relief Valve
If the rupture disk is utilized in multiple series with a pressure relief valve, the disc is typically installed in an upstream of the valve. Then, the disc will secure the valve from the process media, which can destroy or plug. It can also serve as a seal to prevent any potential leakage to the valve if the disk is ruptured.
The space created between the rupture disk and the valve should have a pressure gauge, free vent, telltale indicator, and a try cock. The standard setting of the relief should have a combination of excess flow valve and a pressure gauge. This combination is used to remove the possibility or facilitation of the backpressure build-up.