Safety valves were first used on steam boilers during the industrial revolution. Early boilers without them were prone to accidental Explosion.
Safety valves also evolved to protect equipment such as pressure vessel (fired or not) and heat exchangers. Safety valve term should be limited to compressible fluid application (gas, vapor, steam).
The two general types of protection encountered in industry are thermal protection and flow protection.
For liquid-packed vessels, thermal relief valves are generally characterized by the relatively small size of the safety valve necessary to provide protection from excess pressure caused by thermal expansion. In this case a small valve is adequate because most liquids are nearly incompressible, and so a relatively small amount of fluid discharged through the relief valve will produce a substantial reduction in pressure.
DIN Standard Safety Valve Specification
Type |
Nominal Pressure |
Body Material |
Nominal Diameter |
Working Temp. |
901/902/911/912 |
PN40/16 |
1.0619+N |
DN20/32-DN150/250 |
-10C~450C |
901/911 |
PN40/16 |
1.4408 |
DN20/32-DN100/150 |
-60C~400C |
DN |
20/32 |
25/40 |
32/50 |
40/65 |
50/80 |
65/100 |
80/125 |
100/150 |
120/200/ |
150/250 |
Throat Diameter do
(mm) |
18 |
22 |
29 |
36 |
45 |
58 |
72 |
80 |
100 |
125 |
Orifice Area Ao(mm) |
254 |
398 |
661 |
1018 |
1590 |
2688 |
4072 |
6362 |
8825 |
12266 |
Weight (Kg) |
8.5 |
10 |
14 |
20 |
28 |
40 |
53 |
80 |
125 |
165 |
Safety Valve (Pressure Relief Valve) Dimension
901, 902, 911, 912 Type Safety Valve |
DN×DN1 |
20/32 |
25/40 |
32/50 |
40/65 |
50/80 |
65/100 |
80/125 |
100/150 |
120/200/ |
150/250 |
D |
PN16 |
105 |
115 |
140 |
150 |
165 |
185 |
200 |
220 |
250 |
285 |
PN40 |
235 |
220 |
300 |
K |
PN16 |
75 |
85 |
100 |
110 |
125 |
145 |
160 |
180 |
210 |
240 |
PN40 |
190 |
220 |
250 |
B |
20 |
20 |
20 |
21 |
22 |
24 |
26 |
28 |
31 |
34 |
D1 |
PN16 |
140 |
150 |
165 |
185 |
200 |
220 |
250 |
285 |
340 |
405 |
K1 |
100 |
110 |
125 |
145 |
160 |
180 |
210 |
240 |
295 |
355 |
B1 |
19 |
19 |
20 |
20 |
20 |
20 |
22 |
22 |
27 |
29 |
L |
85 |
100 |
110 |
115 |
120 |
140 |
160 |
180 |
200 |
220 |
L1 |
95 |
105 |
115 |
140 |
150 |
170 |
195 |
220 |
250 |
285 |
≈H |
298 |
311 |
315 |
355 |
405 |
555 |
580 |
690 |
845 |
890 |
Vent(with plug) |
G3/8" |
G1/2" |
Xingtai City Liqian Import & Export Co., Ltd is committed to providing high-quality industrial valves to the international customers. Our factory has a 60-year history on researching, developing, manufacturing and marketing of industrial valve products that are widely used in Oil & Gas, Water Treatment, Power Generation, Petroleum Refinery, Chemical & Petrochemical, and Paper & Pulp industries. It is located in Tianjin-Bohai Economic Center, with strong geographical advantages and development spaces, now becoming the largest valve manufacturer in China. It has passed the authentication of ISO9001: 2008 quality management system, ISO 14001: 2004 environmental management system, and OHSAS 18001: 2007 Occupational Health & Safety System, also with CE, API, KS and GOST certification.
Our exported products include USA ANSI, API, AWWA standard valves, Germany DIN standard valves, England BS standard valves, Japan JIS standard valves, Russia GOST standard valves, France NF standard valves, etc. And the types covering gate valve, globe valve, ball valve, butterfly valve, check valve, diaphragm valve, reducing valve, plug valve, traps valve, etc. With stable quality and long using life, our valves are very popular in USA, Europe, Russia and Middle East markets.
To choose Liqian Valve means to choose safety. We would like to enjoy a win-win cooperation with the customers all over the world!
