Question

What role does safe pressure relief device play for the safe operation of pressure vessel? What are the advantages and disadvantages of the safety valve and the bursting dise? Which occasion are they suitable for? Please give examples. 

Answer 1

Role of pressure relief device:

The role of pressure relief device is to provide a means of venting excess pressure which could damage a boiler or pressure vessel. It is the last line of defence for safety, if all others safety devices or operating control's fail , then the device must be capable in venting excess pressure. There are many types of pressure relief devices such as safety valve,relief valve,safety relief valve and rupture disk.

Advantages and disadvantages of safety valve:

Advantages:

1.it is compatible for wide range of toxic chemicals.

2.it can be operated at high temperature.

3.it has standard pipe dimensions.

4.it can be from sunthessy from wide range of materials.

Disadvantages:

1.it is vulnerable to effects of initial pressure loss .

2.it is not applicable for wide range of pressure difference.

3.it is too sensitive to the effect on back pressure.

4.it effects the set point and capacity.

Advantages and disadvantages of bursting disc:

Advantages:

1.it can be used for low temperature operations.

2. It can easily handle viscous fluids.

3. It works efficiently even if solids are suspended in system fluids.

Disadvantages:

1. If the bursting disc ruptures it cabca be resealed.

2. The temperature hoghlh affects the disc performance.

3.The material used for disc manufacturing is brittle in nature which reduces its strength.

Uses :

Safety valve can be used when the temperature is high and when we are dealing with large range of chemicals . It can also be used even when fouling takes place.

Bursting disc is used when the fluid is viscous or when there are suspended solid particles in the system . It works efficiently at low temperature.