Glossary

Valves, direct-acting

On the direct-acting solenoid valve, the medium flow is switched directly by the armature moved by the magnetic force - unlike on the servo-assisted solenoid valve. In this case, the valve opening (the passage) is generally closed off when de-energized by the armature by means of spring force.

VDE approval as water valve for domestic use

VDE approval as water valve for domestic use

Voltage tolerances

All solenoid-operated control valves for pneumatic actuators are chiefly designed for operating voltages 24 V DC and 24, 110 and 230 V, 50 Hz conventional in the various branches of industry.

Volume Flow

Measuring gaseous substances

Volumetric measuring method: oval gear

Principle of oval gear with pulse output

Vortex

Vortex sensors measure the volume flow that then has to be converted into the mass flow.

Water hammer phenomena

Valve upstream pressure as a function of time when opening or closing the valve

Zero switch-off function

The zero switch-off function ensures that the valve is closed if the input signal is less than 2 % of the maximum value. The coil current is then set to zero. The zero switch-off function must generally be deactivated to set the minimum coil current.

Zero switch-off function

The zero switch-off function ensures that the valve is closed if the input signal is less than 2 % of the maximum value.