Relief valve G 3/4", 12 to 20 bar
Item number:
USV 34-20 ES
Example illustration
Item description
Advantages:
•compact design,
•self-contained gas-tight design,
•optimised with high Kv values,
•can be adjusted externally without disassembly and without special tools,
•wide pressure range coverable with a valve,
•can be used for gas-forming and liquid media
Application:
Relief valves are used in closed circuits to protect pumps from overload. When the adjustable reaction pressure is exceeded, the valve opens in proportion to the overpressure and thus slowly releases pressure. The relief valve is designed to be open for an extended time. As a matter of principle, one must assume that the pressure in the system can exceed the reaction pressure set on the relief valve.

Safety valves have a completely different response characteristic. In the event that the reaction pressure is exceeded by more than 10%, they open almost instantaneously and release all pressure at once. When the pressure comes down to 10-20% below the set reaction pressure, the valve closes again.

Although this function does ensure that the set pressure will not be exceeded by more than 10%, the system will be heavily stressed by the non-proportional opening behaviour.
Version:
Using an Allen key, the relief valves can be adjusted under operating conditions, and without releasing any medium into the surroundings. You are not compensated against back pressure.
Materials:
Body: Gunmetal / brass, spring: stainless steel, seal: FKM (set pressure 12 to 20 bar: PTFE)
Temperature range:
-20 to +200 °C
Media:
Compressed air and other aggressive, non-flammable gases, water and other neutral, non-toxic fluids, mineral oils
Optional:
Body made of stainless steel 1.4401/1.4408 -ES
Properties
Ma­te­r­ial Stain­less steel
re­ac­tion pres­sure [bar] 12 - 20
DN [mm] 20
Thread G 3/4"
Kv value (water)* [l/min] 47 - 12
h [mm] 36
H [mm] 86
L [mm] 40
SW [mm] 36
Further information:
Weight 650 g / pcs
GTIN 4050571714321
Customs duty number 84814010
RoHS compliant Yes
Drawing:
Drawing: Overflow valve
Landefeld Druckluft und Hydraulik GmbH · Konrad-Zuse-Straße 1 · 34123 Kassel · Germany
All data are to be understood as non-binding reference values! We do not assume liability for any data selection not confirmed in writing. Unless otherwise specified, pressure values refer to liquids from Group II at +20°C.
As of: 16.05.2025