The functioning principle of the direct-acting 3-way plunger valve depends on how the fittings are connected to the fluid system. As opposed to the 2-way plunger valve it has two valve seats and one return flow. If no electric voltage is present, a normally closed 3/2-way valve allows no passage from the pressure connection P to connection A (outlet), since a conical spring presses the plunger onto valve seat 1. At the same time, A is directly connected to R (return flow) and valve seat 2 is opened. If the coil is energised the plunger is pulled in and seals valve seat 2. The path between A and R is therefore blocked. At the same time valve seat, 1 is opened and the channel between P and A is opened for the medium.
These valves can be used in diverse applications, such as mixing, distribution, ventilation, dosing, etc. of neutral gaseous and liquid media. This type is frequently used as a pilot valve for larger pneumatically actuated valves. Special features: Special features of this valve type are the convenient, service-friendly manual override, the energy-saving pulse design and its suitability for use in explosive areas. In addition, there are versions that are suitable for high-temperature media (hot water, hot air and steam).