Valvole Hofmann 41RI-VS
SubCategory: SafetyValves
Manufacturer: Valvole Hofmann
Industry:
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Product features
- Self-acting pressure control → operates without external electrical or pneumatic control energy.
- RI pressure-reducing function → reduces inlet pressure and maintains the required downstream pressure.
- VS relief/back-pressure function → opens with rising upstream pressure to control upstream pressure.
- Ductile-iron or AISI 316 body options → supports material selection for different industrial media.
- NBR or EPDM diaphragm options → allows elastomer selection to suit the application.
- Published temperature capability up to +300 °C → supports selected hot-process and steam duties.
- Condensing vessel kit for steam or fluids above +60 °C → protects the diaphragm actuator from excessive control-fluid temperature.
- Leakage class IV → provides a defined shut-off performance for the regulating element.
- DIN or ANSI flanged connections → supports integration with common industrial piping standards.
- Direct mechanical regulation → reduces the number of external instruments required for basic pressure control.
Valvole Hofmann 41RI-VS is a self-acting pressure-control family for systems that need mechanical pressure regulation without an external control-energy source. The RI version reduces inlet pressure and maintains a controlled downstream pressure, while the VS version opens as upstream pressure rises to maintain an upstream pressure limit. Typical media include water, gases and steam when the selected materials and temperature arrangement are suitable.
Both functions use process pressure acting on a diaphragm against an adjustable spring to move the valve plug. RI closes as downstream pressure increases, whereas VS opens as upstream pressure increases, so the two versions should not be treated as interchangeable despite sharing the same product family. The design provides direct local pressure control without a separate transmitter, controller or actuator air supply.
Current manufacturer data lists ductile-iron EN-GJS-400-18-LT and AISI 316 stainless-steel body versions, NBR or EPDM diaphragms, leakage class IV and DIN or ANSI flanged connections. Maximum published temperature is up to +300 °C depending on body and configuration. For steam or process temperatures above +60 °C, the manufacturer specifies a condensing vessel and connection kit so the control fluid reaching the diaphragm actuator remains within its allowable temperature.
Self-acting regulators can simplify pressure-control loops and reduce dependence on external utilities, but correct sizing remains essential to avoid hunting, excessive velocity, noise or unstable pressure. Steam duties in particular require attention to downstream pipe sizing and operating velocity, while material and diaphragm selection should be checked against the medium. AxFlow can support selection of RI versus VS function, sizing, accessories, spare parts and availability.
