Master slide valve located in the dead center

Master slide valve located in the dead center. In this case, high pressure power fluid through the passageway from the center of the tubing into the next cylinder liquid a motive, the end surface of the piston ring action; at the same time, submersible fuel pump  ,high pressure power fluid into the chamber through the channel b c, d and then by passage into the motive fluid to the cylinder, in the upper surface of the piston. Because the piston, under the effect of the two ends of different sizes to produce pressure, fuel dispensing meters motivated by the liquid pump plunger downward. Piston rod is actually an auxiliary control slide valve on the shaft, the lower part of the control slot opened e and f. When the piston rod near the bottom dead center, the upper control channel e communicate on the master slide valve, the lower chamber c and g, a high-voltage power fluid from the control into the main grooves e of the lower end of the slide valve chamberg. Since the end face of the main spool area under an area larger than the upper end, the role of power fluid under high pressure is generated pressure, cause the main control spool to the top dead center, thereby completing the down stroke.