The S3 pressure relief valve from Valfonta is a direct acting device designed to limit pressure in a pipeline by relieving excess fluid when the setpoint is exceeded. Its function is to maintain a stable upstream pressure: if the inlet pressure exceeds the set limit, the valve gradually opens to release the necessary flow.
It is an extremely robust and versatile solution, suitable for steam, gases (groups 1 and 2), and liquids. It stands out for its guided plug design, providing greater operational stability and resistance to turbulence. Available in a wide range of materials (including Bronze and Stainless Steel), it is ideal for demanding industrial applications, pumping systems, and equipment protection.
- Dimensional Range: From DN15 up to DN100 (DN125 and DN150 on request).
-
Set Pressure: Adjustment range from 0.5 to 20 barg using different springs.
-
Body Materials: Great versatility to adapt to the fluid and conditions:
-
Ductile Iron (GJS-400-18-LT) and Bronze (RG-10) for PN25.
-
Carbon Steel (GP240GHN) and Stainless Steel (CF3M) for PN40.
-
-
Internal Parts: Made entirely of AISI 316L Stainless Steel.
-
Temperature Limits:
-
Standard: Up to 220°C with PTFE+Graphite closure.
-
High Temperature: Up to 250°C with special gaskets.
-
-
Shut-off Class: Superior tightness, achieving Class VI (PTFE+GR seat) or Class IV (metal-metal).
-
Connections: DIN / ANSI flanges. BSP/NPT threaded options and weldable (BW/SW) on demand.
The S3 valve operates using direct acting force balance, without the need for auxiliary power:
-
Detection: The fluid pressure at the inlet acts directly on the plug.
-
Proportional Opening: When this pressure exceeds the force exerted by the regulating spring, the valve begins to open. The opening is proportional to the pressure increase, allowing controlled and stable relief.
-
Pressure Maintenance: The equipment continuously modulates to ensure that the upstream pressure does not exceed the set limit. Once the pressure normalizes, the spring closes the valve tightly again.
To ensure the service life and correct operation of the device:
-
Handling: The valve must be protected from dirt and impacts before installation. If lifting equipment is used, never attach them to sensitive parts such as the regulating screw.
-
Pressure Adjustment: The adjustment is made by removing the top plug and turning the adjustment shaft:
-
Clockwise: To increase the set pressure (compress spring).
-
Counterclockwise: To decrease the set pressure.
-
-
Application: It is ideal for pump bypass schemes or line protection, ensuring fluid returns to the tank or recycling circuit.
-
Safety: Although it relieves excess pressure, this device does not replace a certified safety valve if installation requires one by regulation.
