The VD pressure reducing valve by Valfonta is a direct-acting, piston self-operated device. Unlike diaphragm or bellows models, this design stands out for its great mechanical robustness, making it ideal for installations requiring a long service life with minimal maintenance.
Its regulation system features a three-point guided piston, ensuring smooth, stable, and vibration-free movement. It is a versatile and resistant solution, protected with highly durable baked EPOXY paint, designed for the control of liquids, compressed air, neutral gases, and fuel oil in water distribution networks, fire protection systems, and general industrial applications.
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Dimensional Range: Available from DN15 to DN100.
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Maximum Inlet Pressure: Supports pressures up to 40 barg.
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Regulation Range:
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Standard: 1.5 to 8 barg.
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Extended: 1 to 16 barg.
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Body Materials: Wide variety to suit installation:
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Ductile Iron (GGG40.3).
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Carbon Steel (GSC25N).
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Stainless Steel (CF3M - AISI 316).
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Bronze (RG10).
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Internals: Standard made of AISI 316 stainless steel (optionally in Bronze).
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Temperature Limits (according to gaskets):
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Standard (NBR): Up to 80°C.
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Optional (EPDM): Up to 125°C.
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Optional (VITON): Up to 150°C.
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Connections: DIN flanges (PN16/25/40), ANSI (Class 150/300) and Threads BSP / NPT (up to 2").
The VD valve operates on the principle of force balance on a piston.
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Closure by Pressure: The fluid enters the valve and the upstream pressure pushes the piston, exerting a closing force.
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Regulation: When the upper screw is turned clockwise, the spring is compressed, pushing the piston-shutter set downwards and opening the fluid passage until the desired outlet pressure is reached.
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Compensation: The design includes an internal compensation hole in the shaft that connects the chambers to balance the forces. This allows the valve to keep the outlet pressure stable even if there are sharp oscillations in the inlet pressure.
Being a piston valve, it is less sensitive than diaphragm valves but requires specific precautions:
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Filtration (Critical): It is mandatory to install an upstream strainer filter. Solid impurities can scratch the piston sleeve or block its sliding, affecting regulation.
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Position: It is recommended to install on horizontal pipe with the actuator (spring tower) vertically upwards to ensure the best piston guidance.
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Isolation Valves: Install shut-off valves at the inlet and outlet to facilitate maintenance.
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Safety: It is advisable to place a safety valve at the outlet to protect the line from possible overpressures.
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Adjustment: Turn the upper screw clockwise to increase the outlet pressure (+) and counterclockwise to decrease it (-).
