•    The essence of cavitation

    Vapor-filled voids form in the liquid. When the initial pressure value is reached, these vapor bubbles are destroyed. With this destruction, waves arise with pressure peaks in places up to hundreds of bar and with frequencies of several thousand Hertz.
    At impermissibly low suction pressures (absolute pressure between 0.8 and 0.7 bar), cavitation phenomena also occur. Under reduced pressure, the air dissolved in the oil separates. These bubbles are immediately compressed by high pressure also when subjected to temperature.

•    Impact of cavitation

    The harmful effect of these "shocks (water hammers)" on the material of the inner surface of the walls is extremely high. Within a few hours after the “attack” of the bubbles on the surface and parts of the walls, the flow guides break out. High-order oscillations may appear.

•    Causes of cavitation

    Possible reasons are:

    - sudden high fluid velocities due to constrictions and pressure surges;
    - high hydraulic fluid temperatures;
    - too high speed due to changes in the amount of transported material, resistance and, as a result, pressure drop in the suction part of the installation;
    - poor ventilation of the oil tank;
    - large pressure difference;
    - hydraulic fluid condition (age, air content).

•    Opportunities to reduce cavitation

    The following measures should be taken:

    - low suction height;
    - more accurate calculation of the parameters of the oil line;
    - sufficient size of the suction filter;
    - smoothly processed surfaces;
    - low air content in oil;
    - possible increase in pre-pressure on the suction side.