Safety valve, the best extra-pressure protection device takes care of press equipment, container, and online pipe. When the medium’s pressure rises over the allowed pressure, the safety valve will automatically open and truly discharge to protect the equipment from pressure going on rising and will automatically close when the pressure lowers to the set pressure.
Types of spring safety valves
The spring safety valve is mainly divided into closed and open. radiator, lever, and controls can be added. According to the opening height of the safety valve, it is divided into full lift type and low lift type safety valves.
| Structural form of safety valve | |||
| Spring loaded type | Closed | With radiator | Full lift type |
| Low lift type | |||
| Full lift type | |||
| With a lever | Full lift type | ||
| Open | Twin spring loaded low lift type | ||
| Low lift type | |||
| Full lift type | |||
| With controls | Full lift type | ||
| Low lift type | |||
The valve bonnet of the sealed safety valve prevents dust and foreign matters from invading. Meanwhile, protect toxic combustible media from overflowing.
The valve bonnet of the open safety valve can favor the spring seat in lowering the temperature inside. It is mainly used for the pipeline and container with the steam medium. The safety valve with a radiator is suitable for the medium with a temperature over 350℃。
The safety valve with a lever, it makes use of open manually, when the media pressure over 75% of setting pressure.
Full-lift safety valve opening height is more than one-fourth times the flow diameter. It has the advantage of discharging greatly.
Low-lift safety valve opening height is between one-twentieth to one-fortieth times the flow diameter.
Safety valve performance specifications (According to GB12241-2015 and GB12243-2005 standards)
| Import side strngth test Ps(MPa) | Sealing test pressure Pm(MPa) | Opening and closing pressure △P（MPa) | Discharge pressure Pp(MPa) | Opening height H(mm) | |
| Steam safety valve | 1.5PN | 90%Pk or return pressure minimum, choose the smaller one | ≤0.03 when PK≤0.4 ≤10%Pk when Pk＞0.4 | ≤1.03Pk | Full lift type |
| ≥1/4do | |||||
| Using air or other gas valve | Pk-0.03 when Pk≤0.3 90%Pk when Pk＞0.3 | ≤0.03 when PK≤0.2 ≤15%Pk when Pk＞0.2 | ≤1.1Pk | Full lift type | |
| ≥1/4do | |||||
| Using water or other liquids valve | ≤0.06 when PK≤0.3 ≤20%Pk when Pk＞0.3 | ≤1.2Pk | Low lift type | ||
| ≥1/20do |
