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RA Relief Valve

  • Max. Working Pressure: 3.4~300bar

  • DN:5~10mm

  • Working Temperature: -10℃~+50℃

  • Body Material: 304 Stainless steel

Product details:

RA Series Fully Enclosed Safety Relief Valve (1/4″~1″)


Intended for limiting the pressure of liquid or gas systems, thereby preventing system pressure from exceeding the preset safe value (set pressure). when inlet pressure exceeds the set value, the pressure is released through the outlet.


Disk seal: soft seal structure, good gas tightness
● Direct acting construction, flexible valve operation
● Wide range of pressure setting, from 3.4 bar to 300 bar
● Casing pressure rating: 400 bar


Operating Principle: When inlet end pressure goes beyond the set pressure, it overcomes the spring force and opens the disk, and the medium at the inlet end is discharged via the relief valve to the outlet end, thereby controlling the inlet end pressure within the set range. The outlet end generally connects a vent, or it will affect pressure relief. When system pressure falls below the re-seating pressure, the disk and the seat close.


Technical Data
Set pressure repeatability: ±5%
● Min. re-seating pressure: 85%*set pressure 
● Casing material: 304 stainless steel
● Disk material: FPM (set pressure: 3.4~150 bar, -25℃~+150℃) EPDM (set pressure: 3.4~150 bar, -45℃~+100℃) PU (set pressure: 45~300 bar, -25℃~+80℃)
● O-ring material: FPM (-25℃~+180℃), EPDM optional (-45℃~+120℃)


Note: RA series relief valves are used in common pressure relief applications to prevent over-pressure, but not used as relief valves defined in pressure vessel design standards.



Ordering Information


Parameters Table:

Table of Technical Data [mm]


DN Ordering Number Inlet  Outlet Set Pressure 3.4~150 bar Set Pressure 135~300 bar
5 R3A-1/4NPTM-1/4NPT-SS 1/4NPT Male Thread 1/4NPT Female Thread 60 37 28 80 36 28
R3A-R1/4M-R1/4-SS R1/4 Male Thread Rc1/4 Female Thread 60 36 28 80 35 28
7 R4A-R1/2M-R1/2-SS R1/2 Male Thread  Rc1/2 Female Thread 79 42 39 98 44 35.5
10 R5A-R1M-R1-SS R1 Male Thread Rc1 Female Thread 102 62 50 123 57 45.5


Application of Disk and O-ring Materials


Material Uses
FPM Good corrosion resistance; applicable to most media; intolerant of ammonia, alcohols and diethyl ether; temperature: -25℃~+150℃
EPDM Intended for ammonia, vapor, formaldehyde and ethylene glycol; mineral oil intolerant; temperature: -45℃~+100℃
PU Applicable to air, oils and water,temperature: -25℃~+80℃


Table of R3A/R4A/R5A Spring Selection and Disk Materials


Spring Code Pressure Setting Range  Disk Material Valve Series
X 3.4~10bar FPM or EPDM R3A/R4A/R5A
A 8~24bar FPM or EPDM
B 21~50bar FPM or EPDM
C 45~100bar FPM or EPDM
D 90~150bar FPM or EPDM
E 135~220bar PU
F 185~300bar PU


Flow Data at 20℃



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