PRODUCTS
S21
Brass relief valves, suitable for compressed air, gas and liquid.
Product
Relief valve for pressure up to 50 bar (725 psi).
Inlet and outlet connections G 1/4 – F, G 3/8 – F and G 1/2 – F.
Alternative threads available on request.
The relief valve opens when the inlet pressure increases above the set point initially regulated by the adjusting screw and it closes when the pressure goes down under the set point. Set point pressure is controlled by a rubber diaphragm up to 15 bar (217 psi), by a piston for greater pressure.
Available the ATEX 2014/34/EU version.
Brand CE ExII2GcIICTX CE ExII2DcIIICTX.
For use in potentially explosive atmospheres zones:
1, 21, 2, 22 (not in mines and zone 0).
The product complies with the directive 2014/68/EU PED.

CHARACTERISTICS
Technical data
Compatibility | Compressed air | Tecnhical gases and their mixtures | Liquids | Oils |
---|---|
IN/OUT Connection | G 1/4”-F | G 3/8”-F | G 1/2”-F | 1/4”NPT-F | 1/2”NPT-F |
Working Temperature | -4+140 °F standard | From -76 up to +608 °F on request |
Maximum Allowable Pressure (PS) | 22,5 bar (diaphragm) | 70 bar (piston) |
CV (CEI EN 60534-2) | 0,8 US gal/min |
Relief Pressure Ranges | 0,2 ÷ 1,5 | 0,3 ÷ 3 | 0,8 ÷ 8 | 1,5 ÷ 15 | 3 ÷ 30 | 5 ÷ 50 bar |
Weight | ~3,3÷4,4 lb |
Plug Leakage Class | “A” class (UNI EN 12266-1) |
Pressure Gauge Connection | 1/4”-F GAS (Only on request) |
Certifications | PED 2014/68/UE | ATEX 2014/34/UE | EAC TR CU 010 | EAC Ex TR CU 012 |
Internals and Body Material | Brass |
Seals Material | EPDM | FPM | FVMQ | FFKM |
Accesories | Wall mounting bracket |
Spare Parts Kit | O-rings | assembled plug | assembled diaphragm (if applicable) |