Any motor-driven reciprocating pump can be called electric reciprocating pump, according to the use of occasions and the different transmission medium, which can be divided into general and special, special electric reciprocating pump two categories. Most of the general reciprocating pump piston type, usually horizontal and vertical two types. The general horizontal electric reciprocating pump is mainly composed of a pump cylinder part for directly transporting the liquid and a transmission part for reciprocating the reciprocating pump piston. Pump cylinder is mainly composed of pump body, piston, sealing device, suction valve and discharge valve. Reciprocating pump cylinder structure has two types of DC and ladder: DC pump cylinder, the suction valve is arranged in the bottom, the discharge valve is arranged above; stepped pump cylinder, the suction valve and the discharge valve into a 90 ° ladder Arrangement. Reciprocating pump cylinder withstand liquid pressure, it does not allow the presence of pores and cracks and other defects. Pistons is to change the studio volume and suction, an important component of the liquid discharge, divided into two kinds of disk-shaped piston and piston. The disk-shaped piston assembly is mainly composed of a piston, a piston rod and a sealing part. The sealing is generally composed of a cup, a packing and a piston ring; the sealing mechanism of the piston rod is sealed with a packing seal and a sealing ring; the cylindrical piston has only one plunger rod; And reciprocating pump cylinder with. Suction valve and discharge valve is to ensure liquid one-way flow device, a spring valve and gravity valve two: spring valve generally consists of valve seat, valve disc and spring composition, the valve seat and valve disc contact surface with a flat and tapered , It is also called flat valve and cone valve, they are relying on liquid pressure through the opening to open, relying on the valve itself and the spring force to close; ball valve is a kind of gravity valve, it is also through the flow of liquid pressure Open, but only rely on the weight of the ball itself to shut down. Crankshafts are an important part of the entire transmission. Different types of pumps have different crankshaft types. The connecting rod is a connecting member that makes the rotary motion reciprocating. The crosshead is used to connect the connecting rod and the piston, and together they form a set of crankshaft connecting rod mechanism. In order to make the flow uniform, electric reciprocating pumps are almost double-cylinder double-acting type. In addition, the electric reciprocating pump cylinder near the upper discharge pipe is usually equipped with an internal closed air chamber, so that the entire discharge process flow can be further balanced and maintained at a certain value. Vertical electric reciprocating pump internal structure and horizontal the same, but the reciprocating pump cylinder vertical arrangement. General motor and transmission part is located in the upper part of the reciprocating pump, pump cylinder is located in the lower part of the transmission part and the pump cylinder with four steel columns connected into one, and fixed on the pump seat. Vertical electric reciprocating pump supporting the main ship to exclude the bottom water, cargo, oil and auxiliary boiler feed water. Although the general electric reciprocating pump centrifugal pump than the complex, large size, but it has high discharge pressure, high efficiency, and has a unique self-priming performance, especially in the exclusion of bunkering can be intermittent and frequent work, so in the ship Is widely used.