The Four way, three position, Closed Center Valve is an important component in hydraulic circuits for controlling flow direction. In this animation we wanted to show how the direction of the oil flow changed with the different positions of the handle.
You can change the location of the spool by bringing the mouse pointer on the handle and dragging it to the left or right. Different handle ( and spool ) positions, the high (red ) and low (blue ) pressure oil flow will take different paths. The small white circles indicate which direction the oil flows. Notice that the three positions of the spool are indicated by three square blocks in the animation. These square blocks are a symbolic representation of actual oil flowing in the direction of arrows. We also superimposed the white circles in these square blocks to mimic the corresponding flow direction shown in the valve body.
The ports on the valve are marked as P, T, A and B.