Horizontal piston pump is made of several piston (generally 3 or 6) parallel installation, with 1 crankshaft through the connecting rod slider or by the eccentric shaft directly push the piston to do reciprocating motion, realize the suction and discharge of liquid pump. They have also used valve type orifice device, and for most of the quantitative pump. In the coal mine hydraulic support system, the emulsion pump is generally horizontal piston pump.