5 causes of cavitation in hydraulic pumps

Cavitation in hydraulic pumps usually occurs when the local pressure of the liquid in the pump drops below its vaporization pressure. Cavitation can cause damage to the pump body, reduce efficiency, increase noise, and shorten the service life of the pump. To understand the causes of cavitation in gear pumps and quantitative pumps in different applications, it is necessary to combine a number of factors, including pressure differences, flow requirements, material selection and equipment use environment

The main cause of cavitation

1. The inlet pressure is too low: in gear pumps and quantitative pumps, if the inlet pressure of the pump is too low, the liquid will vaporize when entering the pump due to the local pressure drop, resulting in bubbles. These bubbles burst in areas of high pressure, causing cavitation. Especially in the large flow demand, if the system does not do a good job of suction pressure control, the rapid flow of liquid is more likely to lead to the formation of steam bubbles in the low pressure area.
2. The speed of the pump is too high: in the hydraulic transmission system, quantitative pumps and gear pumps are often used in high pressure and large flow applications. If the speed of the pump is set too high, the pressure of the liquid will drop sharply when it flows in the gear meshing area, which is easy to lead to vaporization. This has an adverse effect on the mechanical efficiency and volumetric efficiency of the pump, which in turn affects the stability of the entire system.

3, the liquid temperature is too high: the high temperature liquid vaporization pressure is low, easy to vaporize in the low pressure area of the gear pump, especially in the construction machinery, agricultural machinery and other high load conditions, the liquid temperature is difficult to control, prone to cavitation. To avoid this, thermal management systems and efficient thermal design are essential.

4. Insufficient self-priming capacity: some gear pumps have strong self-priming capacity, but if the pump is improperly designed or installed, the poor self-priming effect will also lead to cavitation. For example, in Marine equipment, construction machinery and other applications, the installation height of the pump and the suction line design is not reasonable will increase the risk of cavitation.
5. Material problems: gear pumps are usually made of cast iron or aluminum alloy, cast iron materials have good wear resistance and strength, but if the pump is in a cavitation environment for a long time, aluminum alloy parts may be more vulnerable to damage than cast iron parts. Therefore, choosing the right material is crucial to improve pump durability and high pressure sealing capability.

The effect of cavitation
·Volumetric efficiency and mechanical efficiency decrease

·Increased noise

·The stability of the pump decreases

Measures to prevent cavitation

1. Optimize the design and selection of pumps: In the case of high flow and high pressure demand, it is recommended to choose gear pumps and quantitative pumps with high efficiency, high performance and high reliability. For example, imported pumps and domestic pumps provided by Rexroth, Parker hydraulic pumps and other brands usually have strong anti-cavitation design and internal leakage control capabilities.
2. Control pump speed and suction pressure: for variable displacement pumps, control pump speed can effectively avoid the emergence of low pressure areas. In applications such as forklift pumps and dual pumps, it is particularly important to select the right pump speed to reduce the risk of cavitation.
3. Strengthen pump maintenance and maintenance: efficient maintenance and after-sales service is the key to ensure long-term stable operation of the pump. Cost-effective solutions from hydraulic manufacturers such as Parker and Rexroth, including technical support and spare parts supply, can help users avoid damage and performance degradation caused by cavitation during long periods of use.

Choose the right pump brand and model

·Parker

·JCB

·CASAPPA

·PGP620

·PGP640

·PGM620

·PGM640