The fluid follows the direction of the arrow placed on the valve body; the flow rate varies according to the position of the plug which increases or decreases the free surface of passage of the fluid.
RI
The valve closes when the downstream pressure increases, the downstream reduced pressure of the valve is conducted to the membrane and transformed into a control force within the servo drive,which moves the plug according to the resistance of the spring, which is adjusted by means of the calibration ring.
For operation with water vapour the dimensioning of the diameter of the tube downstream of the valve must be carried out in relation to the specific volume of the vapour at reduced pressure, it is recommended a steam velocity in the tube downstream of the reducer not exceeding 50 m/s.

For operation with water vapour, or fluids with temperature greater than 60°C require kit composed of:
- condensing barrel
- copper tube (2m)
- fittings (order code: RI.KIT)
In no case shall the temperature of the control fluid arriving at the servo control be higher than 60°C.
VS
The valve opens when the upstream pressure increases, the upstream pressure of the valve is conducted to the membrane and transformed into a control force inside the actuator, which moves the plug according to the resistance of the spring that is adjusted by the calibration ring.
