Hydraulic pumps convert mechanical energy into hydraulic energy in the system. It pressurizes the hydraulic fluid and provide flow for the application. Classification includes many different designs such as external gear pumps, internal gear pumps, piston pumps and vane pumps. Working conditions of our system are important for selection of the pump. For example, piston pumps are preferred instead of gear pumps in systems where operating pressure is 300-350 bar.
In this article, we will try to explain how to change rotation of an external gear pump. Gear pumps can be single direction or reversible. They get mechanical energy from an electric motor or a gasoline engine. If gear pump is connected to the electric motor, we can easily change the rotation of electric motor but if gear pump is connected to a gasoline engine with a belt connection or if it is directly connected to a gearbox, we may need to change the rotation of gear pump.
Below you can have a look how to change rotation of a single, group 20 aluminum external gear pump. Hope it will be helpful!
Before starting rotation change, we must make sure that our working area is clean.
4 pieces connection bolts of the gear pump are disassembled. The front cover is removed carefully without damaging the shaft seal.
Drive gear (Longer gear, shaft) and upper bushing are removed carefully. O-rings are checked.
The position of driven gear (short gear) in the body is changed. So it is put in place of the drive gear.
Similarly, the drive gear position is replaced by the driven gear.
Then the front bushing is placed exactly as it was removed. O-rings are checked. There are channels on the bushing. It should be noted that these channels must always face to suction port (inlet line) side. It should be placed in the same way as it was removed. You can use an oilcup for lubricate.
Back cover connection bolts are tightened. It would be good to refer tightening torques recommended by the manufacturer. The location of the suction and pressure ports on the body does not change. Rotation of the shaft is checked with a wrench.
External gear pump designs may be different for manufacturers. In some designs, o-rings can be on flanges. At that point; for rotation change, front cover needs to be change as well.