Safety Relief Valve

Spring Loaded Safety Relief Valve For Liquid

Spring-loaded safety relief valve works through adjusting spring force to prevent medium pressure and realize sealing purpose. Under the condition of spring force greater than medium's normal pressure, valve disc is at the close state, when medium pressure exceeds the set pressure, the spring is compressed, and lead the disc sealing faces separated, the valve open automatically, and relief pressure; When medium pressure reduced to normal pressure, the valve disc go back to valve seat under the spring force, disc sealing faces and valve seat sealed again, the valves close automatically.

Spring Loaded Safety Relief Valve For Liquid


  • Enclosed Bonnet
  • Low lift/Full lift safety valve metal to metal seated,standard safety valve for liquids
  • Flanged connection acc. to ASME,DIN,JIS,BS etc.


Provided as safety device for protection against excessive pressurein pressure vessels

Approved for gases and fluids

Working temperatures:-60°Cup to +200°Cfor stainless steel material

-29°C up to300°C for cast steel material

Standards Compliance:

Design and Manufacture:API RP 520

Face to Face(end to end):API 526

Test and Inspection:API 527


  1. spring loaded low lift enclosed bonnet safety relief valve(A41)
  2. spring loaded Full lift enclosed bonnet safety relief valve(A42)
  3. spring loaded Full lift enclosed bonnet safety relief valve with lever(A44)

In order to offer a quotation,we need specifications as following:

  1. Flange Connection standard
  2. Pressure Rating
  3. Size
  4. Set Pressure
  5. Material for Body&Trim (Material for inside parts).
  6. Operation type: With lever or not
  7. Medium
  8. Working Temperature

Spring Loaded Safety Relief Valve For Liquid( Main property specifiecation)

Nominal pressure PN(Class) 150 300 600 900 1500
Body strength Ps(Mpa) 3.0 7.5 15 22.5 37.5
Set pressure Pk(Mpa) 0.1-2 1.6-5 3.2-10 8-25 10-25
Seal pressure Pm(Mpa) 90%Pk
Reseation pressure Ph(Mpa) ≥90%Pk
Relieving Pressure Pp(Mpa) ≤1.1Pk
Lift height H(mm) ≥1/20 d0
Appropriate temp. ≤200℃
Appropriate Medium C(WCB) P, R (SS304, SS316) Gas, Liquid Nitric Acetic Acid, Gas, Liquid

Spring Loaded Safety Relief Valve For Liquid (Code of throat diameter)

Code Diameter Code Diameter
D 10 L 50
E 13 M 55
F 16 N 60
G 20.5 P 72
H 26 Q 96
J 33 R 115
K 40 T 148

Materials for main parts

No Name of part Materials A42H-C Material A42Y-P Material A42Y-R
1 Body WCB CF8 CF8M
2 Nozzle 2Cr13/ 304 CF8 CF8M
3 Adjusting Ring 2Cr13/ 304 304 316
4 Disc 2Cr13/ 304 304 316
5 Guide sleeve 2Cr13/ 304 304 316
6 Bonnet WCB CF8 CF8M
7 Spring 50CrVA 50CrVA coated teflon 50CrVA coated teflon
8 Stem 2Cr13 304 316
9 Adjusting bolt 45 2Cr13 2Cr13
10 Cap ZG200-400 ZG200-400 ZG200-400

Sealing surface of material "H" depositing D507, "Y" depositing stellite

Drawing For Example:

Spring Loaded Safety Relief Valve For Liquid

For more details, please download catalogue for reference or contact with us.

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