One. The main structure of the reciprocating pump and the main working principle Working principle: When the piston moves from left to right to form a negative pressure within the pump cylinder, sump liquid into the pump cylinder through the suction valve. When the piston moves from right to left, the liquid in the cylinder is squeezed, the pressure increases, and it is discharged by the discharge valve. Pistons reciprocate, each suction and discharge a liquid, called a work cycle; this pump is called a single action pump. If the piston from time to time, each inhalation and discharge of liquid twice, known as double-acting pump. Pistons move from one end to the other end, called a stroke. Reciprocating pump flow and head reciprocating pump flow and pressure head has nothing to do with the size of the pump cylinder, piston stroke and reciprocation frequency. The theoretical flow of a single acting pump is: QT = Asn The actual flow of the reciprocating pump is smaller than the theoretical one and decreases with the increase of the pressure head, which is caused by the leakage. Reciprocating pump head and pump flow and pump geometry has nothing to do, but by the pump mechanical strength, the power of the prime mover and other factors. Reciprocating pump installation height and flow adjustment Reciprocating pump start without filling liquid, because the reciprocating pump self-priming capacity, but the vacuum suction height also depends on the installation area of ​​?? the atmospheric pressure, the nature of the liquid and the temperature changes , So the reciprocating pump installation height also has certain limit. Reciprocating pump flow can not be discharged with the valve on the pipeline to adjust, but should be used by the bypass pipe or change the reciprocation of the piston to change the piston stroke to achieve. Before starting the reciprocating pump, the valve in the discharge line must be opened. The piston of the reciprocating pump is connected with the prime mover by the connecting rod crankshaft. The prime mover can be used motor, steam engine can also be used. Reciprocating pumps for high-pressure head, small flow, high-viscosity liquid delivery, but not for transporting corrosive liquids. Sometimes directly driven by the steam engine, delivering flammable, explosive liquids.