Safety valve is a valve that act
as a protection of equipment from exploding or damaging and it is mainly
installed in pressure vessels such as chemical plants, electric power boilers
and gas storage tanks.
Safety Valve is a type of valve that automatically actuates when the pressure
of inlet side of the valve increases to a predetermined pressure, to open the
valve disc and discharge the fluid (steam or gas); and when the pressure
decreases to the prescribed value, to close the valve disc again. Safety valve
is so-called a final safety device which controls the pressure and discharges
certain amount of fluid by itself without any electric power support.
Safety valve support not only the safety of energy industry but also the safety
and security of our life.
Function of Safety Valve
1."Nozzle" inside the Safety Valve starts to receive a higher pressure from the inlet side of the valve.
2.When the pressure becomes higher than the set pressure, "Disc" starts to lift and discharge the fluid.
3.When the pressure decreases until the predetermined pressure, the force of the spring closes "Disc".
Classification of safety valve
Spring-loaded Pressure-relief Valves
Generally,
the safety valves are referred to the Spring-loaded
Pressure-relief valves, the most common type.
The load of the spring is designed to press the "Disc" against the
inlet pressure.
Depending on the fluid type, such as steam, gas or liquid, we are offering a
Bellows model to clear the back pressure effect.
Pilot-operated Pressure-relief Valves
Pilot-operated
Pressure-relief Valves are composed of Pilot Assay and Main Valve. Although
Spring-loaded Pressure-relief valves adopts the force of the spring against the
inlet pressure, the reliving pressure and reseating pressure of the
Pilot-operated Pressure-relief Valves is controlled by Pilot Assay, which acts
nearly as same as Spring-loaded Pressure-relief valves. There is no adjusting
function in the Main Valve.
Pilot-operated Pressure-relief Valves have larger size variations compared to
Spring-loaded type, which is applied in a severe condition such as high pressure.
Dead-Weight Pressure-relief Valves
In case the design pressure of
the pressure vessel is set at very low pressure, Dead-weight Pressure-relief
valve adjusts relieving pressure only by the disc weight.
The Vacuum relief valve has been adopting this functional characteristic which
absorbs the pressure when the inside of the pressure vessel falls into a
negative pressure.