Positive displacement pumps rely on working elements in the pump cylinder reciprocating or rotary motion, the work volume alternately increase and decrease in order to achieve liquid inhalation and discharge. Suction and discharge of positive displacement pumps are closely spaced. The reciprocating motion of the working elements of the positive displacement pump called the reciprocating pump, known as rotary motion rotary pump. The former suction and discharge process alternately in the same pump cylinder, and by the suction valve and discharge valve to be controlled. The latter forces the transfer of liquid from the suction side to the discharge side by the rotation of working elements such as gears, screws, leaf rotors or vanes. They do not require suction and discharge valves. The radial rotary piston pump and the axial rotary piston pump respectively perform the suction and discharge functions by reciprocating the plurality of plungers arranged radially and axially in the rotor respectively during the rotation of the rotor, As a special type of rotary pump. Powered pumps rely on the impellers' ability to quickly rotate the impeller to transfer mechanical energy to the fluid to increase its kinetic energy and pressure, which in turn translates most of the kinetic energy into pressure energy through the pump cylinder. Power pump, also known as impeller pump or vane pump. Centrifugal pumps are the most common type of power pump. One type of pump that other types of pumps deliver energy in other ways. For example, a jet pump relies on a high-speed jet of working fluid to draw the fluid to be pumped into the pump and transfer energy by mixing the two fluids for momentum exchange. Water hammer pump is the use of water flow in the sudden brake when the energy generated, so that part of the water pressure rose to a certain height. Electromagnetic pump is the power of the liquid metal in the electromagnetic force generated by the flow and delivery. The gas lift pump delivers compressed air or other compressed gas to the bottom of the liquid through the conduit to form a lighter liquid gas-liquid mixture, which is then pressurized by the pressure of the external liquid.