Many applications require the use of a 3/2-way valve, e.g. to enable the ventilation of a cylinder or to mix or distribute gases and liquids. The use of a 3/2-way valve allows a single valve to be used where otherwise two 2/2-way valves would be necessary.
Similar to 2/2-way valves, 3/2-way valves can also be realized as NC and NO variants. The most common implementation of an NO function with a 3/2-way valve is similar to the NC valve as shown in the illustration below left, but a different connection is used as the input and the internal springs are selected accordingly. The connection on the guide tube, which is connected to the outlet (connection 1) when de-energized, serves as the inlet. When the valve is actuated, the plunger is pulled to the pole and closes the pole nozzle so that venting can take place from the outlet in the direction of port 2. In some applications, it is intended that the connection on the guide tube is only used for venting, which does not allow a design as shown in the illustration below left. This requires an NO system design as shown in the figure below on the right, in which both the inlet and the outlet are realized in the valve body and the venting takes place via the guide tube.
Both variants are available from SVS-Automation as 3/2-way NO valves in the form of valve types 82, 84, 92 and 94 or also individually as a solenoid system for integration by the customer.
