The function of a hydraulic pump is to convert the mechanical energy of a power machine (such as an electric motor and an internal combustion engine, etc.) into the pressure energy of a liquid. The output flow rate can be adjusted according to the need is called variable pump, the flow rate can not be adjusted is called quantitative pump.
Types of commonly used hydraulic pumps
According to whether the flow can be adjusted can be divided into: variable pumps and quantitative pumps. Output flow can be adjusted according to need is called variable pump, the flow can not be adjusted is called quantitative pump.
Classification of hydraulic pumps, selection and symbols according to the shape of the moving parts and movement is divided into: gear pumps, vane pumps, piston pumps, screw pumps and so on.
Gear pumps and external gear pumps and internal gear pumps. Vane pumps are divided into double-acting vane pumps, single-acting vane pumps and cam rotor pumps. Piston pumps and radial piston pumps and axial piston pumps. According to the displacement can variable quantitative pumps and variable pumps. Single-acting vane pumps, radial piston pumps and axial piston pumps can be used as variable pumps.
Working conditions of hydraulic pump
Must have a moving parts and non-moving parts of the composition of the confined volume; the size of the confined volume with the movement of the movement of the movement of the pieces of the cyclical changes in the volume from small to large - oil suction, from large to small - oil pressure; confined volume increased to the limit, the first to be with the suction When the closed volume increases to the limit, it should be separated from the suction chamber first, and then turn to oil discharge; when the closed volume decreases to the limit, it should be separated from the oil discharge chamber first, and then turn to oil suction.
The main parameters of hydraulic pump
1,Pressure
Working pressure is the output pressure when the hydraulic pump is actually working. Depends on the size of the external load and the pressure loss on the discharge pipe, but has nothing to do with the flow of the hydraulic pump.
Rated pressure, is a hydraulic pump under normal operating conditions, according to the test standards for continuous operation of the highest pressure known as the rated pressure of the hydraulic pump.
Maximum allowable pressure, is in excess of the rated pressure conditions, according to test standards, allowing the hydraulic pump to run briefly the highest pressure value.
2, displacement and flow
Displacement, is a hydraulic pump every turn of the week, calculated by the geometric size of its sealing volume changes in the volume of discharged liquid.
Theoretical flow refers to the hydraulic pump without taking into account the conditions of the leakage flow, the volume of liquid discharged in a unit of time. If the displacement of the hydraulic pump for V, its spindle speed for n, the theoretical flow of the hydraulic pump: qt = Vn
Actual flow, is a hydraulic pump in a specific operating conditions, the volume of liquid discharged per unit of time is called the actual flow, equal to the theoretical flow minus leakage and compression losses.
Rated flow rate, qn in normal operating conditions, the test standard provisions (such as in the rated pressure and rated speed) must ensure the flow rate.
Hydraulic pump selection principles
Whether the requirements of variable, variable selection of variable pumps; working pressure, the highest rated pressure piston pumps; working environment, gear pumps are the best anti-fouling ability; noise indicators, double-acting vane pumps and screw pumps belong to the low-noise pumps; efficiency, axial piston pumps have the highest total efficiency.
