The S1 pressure relief valve from Valfonta is a self-acting overpressure device designed to limit the maximum pressure in a process line or protect sensitive equipment by diverting excess flow. Unlike a quick-release safety valve, the S1 offers a proportional opening to the increase in inlet pressure, allowing stable and precise relief control.
Its robust construction includes a double-layer stainless steel bellows with an anti-torsion system, ensuring absolute shaft tightness to the outside (zero emissions) and friction-free operation. It is a versatile solution suitable for working with steam, compressed air, neutral gases, and liquids, offering a quick and effective response to demand changes in the system.
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Dimensional Range: Standard from DN15 to DN100 (DN125 to DN200 on request).
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Nominal Pressure: Available in PN16, PN25, PN40 and ANSI Class 150 / 300.
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Regulation Range: Allows adjustment of the set pressure (relief) between 0.1 and 15 barg.
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Body Materials:
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Ductile Iron (GGG40.3).
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Carbon Steel (WCB).
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Stainless Steel (CF3M - AISI 316).
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Internals: Seat, disc, and internal parts made of AISI 316L Stainless Steel.
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Temperature Limits (Membrane Material):
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NBR: -20°C to 80°C.
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EPDM: -40°C to 125°C.
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EPDM + PTFE (with condensation tank): 125°C to 220°C.
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Design: Single seat globe valve with reinforced diaphragm chamber.
The S1 valve operates by balancing the forces between the inlet pressure and the regulating spring.
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Normal State (Closed): The spring force keeps the disc seated while the inlet pressure is below the set value (set point).
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Detection: The inlet pressure is transmitted to the actuator chamber through an external control line.
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Opening (Relief): When the inlet pressure exceeds the adjusted spring force, the diaphragm moves compressing the spring and opens the valve. This allows the fluid to escape to the return or relief line, reducing the pressure in the main line.
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Closing: As soon as the inlet pressure drops below the set point, the spring pushes the disc back, closing the valve.
To ensure operational reliability, follow these specific instructions:
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Mounting Position: It must be installed in a horizontal pipe respecting the flow direction.
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Standard: Actuator vertical upwards (Mandatory for fluids at T > 80°C).
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Inverted: Allowed only for gases/liquids at T < 80°C.
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Control Line (Sensing Line):
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It must be connected to the inlet pipe (upstream), at a minimum distance of 1 meter from the valve.
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A 10x1 mm tube is recommended.
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If the pressure fluctuates, install a needle valve in this line to stabilize the reading.
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Condensation Tank (Drum):
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Mandatory for steam and liquids at T > 125°C.
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Protects the diaphragm from high temperatures and must be filled with water before start-up.
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Filtration: Always install a strainer before the valve to protect the seal.
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Adjustment: Turn the upper nut clockwise to increase the relief pressure (compress spring) and counterclockwise to decrease it.
