The pump body of petrochemical gear pumps will not have clearance fit and outlet pressure issues

（1） The concept of a gear pump is very simple. Its basic form is that two gears of the same size mesh and rotate with each other in a tightly fitted housing. The interior of the housing is similar to an "8" shape, and the two gears are installed on the inner surface. The outer diameter and both sides of the gears are tightly fitted with the housing. The material from the extruder enters the middle of two gears at the suction port and fills this space. It moves along the shell with the rotation of the teeth and is then discharged when the two teeth mesh

In terms of terminology, a gear oil pump is also known as a positive displacement device, which is like a piston in a cylinder. When one tooth enters the fluid space of another tooth, because the liquid is incompressible, the liquid and the tooth cannot occupy the same space at the same time. In this way, the liquid is mechanically squeezed out. Due to the continuous meshing of teeth, this phenomenon occurs continuously, providing a continuous discharge capacity at the pump outlet. The discharge capacity is the same for each revolution of the pump. As the drive shaft rotates continuously, the pump continuously discharges fluid. The flow rate of the pump is directly related to the pump speed

In fact, there is a small amount of fluid loss inside the pump because this fluid is used to lubricate both sides of the bearings and gears, and the pump body does not fit seamlessly, so it cannot discharge the fluid 100% from the outlet. Therefore, a small amount of fluid loss is inevitable, which makes the pump's operating efficiency unable to reach 100%. However, the pump can still operate well and achieve an efficiency of~for most extruded materials

(II) Outlet pressure problem of gear pump

Gear pump is a rotary pump that relies on the working volume change and movement formed between the pump cylinder and the meshing gear to transport liquid or increase pressure.

. Two enclosed spaces are formed by two gears, the pump body, and the front and rear covers. When the gears rotate, the volume of the space on the disengaged side of the gears increases from small to large, forming a vacuum that sucks in the liquid. The volume of the space on the meshing side of the gears decreases from large to small, and the liquid is squeezed into the pipeline. The suction and discharge chambers are separated by the meshing lines of two gears. The pressure at the discharge port of a stainless steel gear oil pump depends on the resistance at the pump outlet

When the gear pump is working, the driving wheel rotates together with the electric motor and drives the driven wheel to rotate accordingly. When the meshing teeth on one side of the suction chamber gradually separate, the volume of the suction chamber increases, the pressure decreases, and the liquid in the suction pipe is sucked into the pump; The inhaled liquid is divided into two paths and pushed into the discharge chamber by the gear in the tooth groove. After the liquid enters the discharge chamber, due to the continuous meshing of the teeth of the two gears, the liquid is compressed and enters the discharge pipe from the discharge chamber. The driving gear and driven gear rotate continuously, allowing the pump to continuously suck in and discharge liquid

A gear pump is a rotary pump that relies on the variation and movement of the working volume between the pump cylinder and the meshing gear to transport liquid or increase pressure

Two enclosed spaces are formed by two gears, the pump body, and the front and rear covers. When the gears rotate, the volume of the space on the disengaged side of the gears increases from small to large, forming a vacuum that sucks in the liquid. The volume of the space on the meshing side of the gears decreases from large to small, and the liquid is squeezed into the pipeline

The suction and discharge chambers are separated by the meshing lines of two gears. The pressure at the discharge port of a gear pump depends on the magnitude of the resistance at the pump outlet