1. Plunger pumps. Piston pumps in all types of pumps in the status of the aristocrats like, high cost, good quality, reliable performance. But also has its shortcomings, the volume is too large, sensitive to oil pollution, the environmental requirements relative to other pumps is the highest.
2. Vane pump. Vane pump has the amount of uniform, smooth operation, low noise: the rotor is subjected to radial hydraulic pressure to balance each other 〃 bearing life, durability: high volumetric efficiency, up to 95% or more: the working pressure is high. At present, the working pressure of double-acting vane pumps is 6.86-10.3 MPa, sometimes up to 20.6 MPa: compact structure, small external dimensions and large displacement and other advantages. Its shortcomings are also very obvious, as with the piston pump, sensitive to oil pollution, the structure is more complex compared to the gear pump, the same high requirements for the working environment, the cost relative to the piston pump, it will be cheaper.
3. Gear pumps. Gear pumps compared to vane pumps and piston pumps, gear pumps have a lot of advantages, and at the same time, incidental disadvantages are also many. Advantages are: small size, light weight, simple structure, easy to manufacture, low price, reliable, good self-priming performance, insensitive to oil contamination, easy maintenance and so on.
At the same time, the accompanying disadvantages are flow and pressure pulsation, work noise, on the staff and the environment caused by a greater nuisance, the displacement is not variable, can not be with the vane pumps and piston pumps as well as to achieve the same effect of variable.
4. Screw pumps. Screw pumps relative to the above three hydraulic pumps, belonging to a relatively small number of pumps, because in many industries, screw pumps can not reach the pressure level required by customers. But it also has a simple structure, safe and reliable, easy to use and maintain, continuous and uniform liquid, stable pressure and other advantages, is widely used in various low-pressure industry.
