This is a 2/2-Directional valve that is designed for installation in a control block. If came about as a result of efforts to simplify controls by breaking down the functions of conventional directional valves into individual functions and combining these functions and making it possible to operate them as required.
In this way the function of a 4-direction valve is replaced by four single valves that can now be operated, e.g. also with overlaps (Figure Z 16). This procedure is cost effective because the same basic 2/2 unit can also be used, given appropriate operation, as a check valve, pressure valve or as a throttle valve and that in some circumstances even with the multiple operation of an individual plug-in valve.
The layout is typically that of seated valves that are inserted in a bore in accordance with DIN 24 342 and that are sealed upwards by a control plate. They can also be in the form of spool valves as normally closed or normally open valves (Figure Z 17). The pilot valve required is fitted to this plate (Figure Z 18). For directional valves this is either a normal solenoid valve for switching functions or a proportional valve for continuous functions. The pressure and flow valves can also be operated by conventional means or using proportional valves.
The circuit symbols are defined in DIN 24 342 data sheet 1.
Figure Z 16: Schematic diagram of a control with 2-way plug-in valves
Figure Z 17: Types of 2-way plug-in valves
Figure Z 18: 2-way plug-in valve with pilot control