Reciprocating pump is a positive displacement pump that is depend on the piston, piston or diaphragm in the pump cylinder reciprocating movement to make the working volume alternately increased and reduced in cylinder, so as to achieve purpose of liquid in transmission or booster. There are many characteristics of reciprocating pump, including self-absorption capacity and high efficiency, and the following is to introduce the measures to improve the volumetric efficiency of reciprocating pump. There are many types of liquids. For reciprocating pumps, different kinds of liquids need to be noticed differently; It is like high viscosity liquid, because the suction resistance is large, when the suction pressure head is not enough, use the sealed water tank, also can use inert gas or use centrifugal pump to pressurize. General viscosity under 7 ° E (engler viscosity), ordinary liquid consideration; Viscosity is higher than 7 ° E, must reduce the rotational speed of the pump; Viscosity reaches 65 ° E, the rotational speed of the pump should be down to 60% of the rating.
For high temperature liquid, except for special occasions, for liquid under 120 ℃, and the temperature more than the value of time, you need to pump speed drop below 70% of the rated speed, in order to prevent the occurrence of cavitation phenomenon; For volatile liquids, because of the high vapor pressure, it is necessary to increase the elevation of the suction side container and reduce the suction resistance.
In addition, in order to improve the volumetric efficiency of reciprocating pump, it is necessary to reduce the clearance volume as much as possible. There should be no particle impurities in the liquid, otherwise it will cause damage to the packing and plunger. In addition, the total length of the pipe should be less than 30m, and the pipe should be as thick, short and straight as possible to reduce the suction resistance and improve the volumetric efficiency of the compound pump.