Try out the switch positions! The standardization signs of the hydraulics, depict the directional valves as a type of slider. The important thing is, that any connection coming from the outside is guided further, even if it ends here. The conveyor unit should probably, be installed below the directional valve. In one of the switched-on positions there is continuous conveying. After switching off, all the lines are are blocked.
Here, from below, next to the feed line on the left, another line, the flow-back, comes in. When switching on, the pressure is built up from below left to the above right and the flow-back line is closed. When switching off, the built up pressure can escape through the flow-back line.
In this case, there are two lines at the top, where optionally, pressure is built up. Should one be connected to the conveyor unit, then the pressure is reduced through the other in the direction of the flow-back line. The disadvantage here is, that there is no neutral position.
So, now the neutral position is also present. For this however, we need three switch positions. In this case, one speaks of a 4/3 directional valve, whereby, the first number indicates the number of connections and the second, the number of switch positions. 05/12