Gear pump is a positive displacement rotary pump, the working principle is: gear pump has a pair of intermeshing gear, the gear (drive wheel) is fixed on the drive shaft, one end of the gear pump shaft out of the shell driven by the prime mover , And the other gear (driven wheel) of the gear pump is mounted on the other shaft. When the gear of the gear pump rotates, the liquid enters the suction space along the oil suction pipe and is pressed against the discharge space by the two gears along the upper and lower shell walls, respectively Tooth meshing with the teeth before), and then into the pressure tubing discharge. The main features of the gear pump is compact, small size, light weight, low cost. However, compared with other types of pumps, low efficiency, vibration, noise and easy wear shortcomings. Gear pumps are suitable for conveying viscous liquids.