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Home arrow Valve Systems arrow Basic Functions
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Basic functions of the valve functionality
  Material for sealing and the diaphragm

Solenoid valves consist out of two major component groups, the electrical solenoid with the piston and magnet armature as well as the valve body. Inside the valve body a valve disc or cone is used to open/close the discharge path opening. Depending on the design, the solenoid valves can be operated and loaded in different ways.

We are going to explain some of those here:

The operation will open the orifice of a normal closed valve or close the orifice of a normally open valve, when the solenoid is energised. On release a spring returns the valve in its original position. It will operate at pressures from 0 up to its rated maximum.

Sample models are:  AL 01, AL 02, AC 01, AC 02


Internal pilot-operated (servo) valves normally have a pilot and bleed orifice, which enables them to use line pressure for operation. When the solenoid is deenergised, the pilot orifice is closed and full line pressure is applied to the top of the piston or diaphragm through the bleed orifice, providing the seating force for tight closure.
This operation method requires a certain difference in the pressure across the valve ports.

Sample model is:  AL 03

force pilot-operated

This design combines both of the above systems. Because of using it with a stronger electrical drive part, there is no must have for any pressure difference. But existing pressure will assist the operation.

Sample model is:  AL 04

Δ pmax.

This refers to the largest sllowed pressure difference between the input / output ports of a valve, where the solenoid system is still able to safely operate the valve. Independed if this is a direct action or servo operadet valve. This may be further limited, by the maximal pressure (PN) allowed for the valve body and sealing.

Δ pmin.

The smallest pressure difference between the input and the output port of a valve, where the servo supported solenoid system is able for a safe operation.


This is the flow coefficient. It specifies the flow rate of water as m³/h with a pressure drop of 1 bar, at an average temperature of 20°C.


Standard material for neutral, gaseous and fluid media and air, water and oil. Elastometer with good mechanical firmness, small pouring inclination and small abrasion. For most applications it is sufficiently protected against aggression through ozon.

Media temperature range: -10°C to +90°C

EPDM (Dutral)

A general-purpose elastometer, suitable for applications above the NBR temperature range, such as of hot water and steam, with a good combination of corrosive and abrasive resistance. Very low vapour and gas permeability.

Media temperature range: -20°C to +130°C.


FKM (Viton)

FKM has a rather wide range of chemical compatibility. It was primarily developed for handling of hydrocarbons such as jet fuels, gasoline's, and solvents that normally caused detrimental swelling to NBR. The elasticity will degrade at low media temperatures.

Media temperature range: -10°C to +150°C


A plastometer known to have objectionable "cold flow" characteristics, but still usable in refrigeration system. Because of the smoothness in the surface it has a very low coefficient of friction. PTFE is virtually not attacked by any fluid media.

Media temperature range: up to +250°C.

VMQ (Silicone)

Robust on aggressions through oxigen and ozone. Keeping a good heat resistance and maintaining the good flexibility in a cold environment at the same time. No hardening under the influence of oil and additives.

Media temperature range: -40°C to +130°C

CSM (Hypalon)

Excellent stability against ozone- and climatic influence. Extremly resistant against oxidising chemicals.

Media temperature range: -10°C to +100°C.

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