Tandem Gear Pump & Their Features:

The basic form of hydraulic tandem gear pump is that two gears of the same size engage and rotate each other in a closely matched shell. The inner part of the shell is similar to the "8" shape. Two gears are installed inside, and the outer diameter and sides of the gear are closely matched with the shell. Material from the extruder enters into the middle of the two gears at the suction port and fills the space. It moves along the shell with the rotation of the teeth, and finally discharges when the two teeth engage.

In terminology, tandem gear pump is also called positive displacement device, that is, like a piston in a cylinder, when one tooth enters the fluid space of another tooth, because the liquid is incompressible, so the liquid and the tooth can not occupy the same space at the same time, so the liquid is mechanically squeezed out. Because of the continuous meshing of teeth, this phenomenon occurs continuously, thus providing a continuous exclusion quantity at the outlet of the pump. Every turn of the pump, the discharge quantity is the same. With the uninterrupted rotation of the drive shaft, the pump also discharges fluid uninterruptedly. The flow rate of the tandem gear pump is directly related to the speed of the pump.

External Gear Pump

In fact, there is a small amount of fluid loss in the pump, because these fluids are used to lubricate both sides of bearings and gears, and the pump body is never able to cooperate without clearance, so the fluid can not be discharged 100% from the outlet, so a small amount of fluid loss is inevitable, which makes the operation efficiency of the pump can not reach 100%. However, the external gear pump can still run well, and for most extruded materials, the efficiency can still reach 93%-98%.