CAVITATION IN HYDRAULIC PUMPS AND ITS CAUSES
In this week’s blog post, we will discuss cavitation, a phenomenon that negatively affects hydraulic systems by reducing performance and damaging components, particularly hydraulic pumps. Cavitation shortens the lifespan of many system components and can lead to costly failures.
Cavitation in hydraulic pumps occurs when the pressure of the fluid inside the pump drops below its vapor pressure. This pressure drop causes vapor bubbles (air pockets) to form in the suction line of the pump. When these bubbles travel to high-pressure areas, they collapse violently, damaging the pump surface. Although these bubbles may seem harmless, they create a shockwave effect on the surface of the pump body.
Cavitation significantly reduces pump performance, decreases system efficiency, and shortens equipment lifespan. Additionally, it causes noise and vibration, which can lead to even greater system failures.
Main Causes of Cavitation
- Low Pressure in the Suction Line (Excessive Vacuum)
When the pressure at the pump inlet is too low, the fluid’s vapor pressure is exceeded, and vapor bubbles form. - High Operating Speed
Operating the pump at speeds above its nominal range lowers the inlet pressure further, leading to cavitation. - Narrowing of the Suction Line
Restrictions or reduced pipe diameters in the suction line increase flow velocity and reduce pressure. This is one of the most critical causes of cavitation. - Increased Fluid Temperature
Higher fluid temperatures raise the vapor pressure, making the fluid more likely to vaporize at lower pressures and causing cavitation. - Dirty or Incorrect Hydraulic Oil Usage:
Using contaminated oil or oil with improper viscosity can hinder the movement of fluid in the system and contribute to cavitation.
In addition, situations such as the pump being located too far from the oil tank, sharp bends in the suction line, and clogged components like filters and breather caps can also lead to cavitation.
Cavitation Prevention Methods
- Eliminate restrictions in the pump’s suction line and design pipe diameters appropriately.
- Use clean hydraulic oil with the correct viscosity to ensure smooth fluid movement within the system.
- Keep the pump’s operating speed within the manufacturer’s recommended range.
- Use oil coolers effectively to control fluid temperature.
- Keep filters clean and regularly monitor pressure losses in the system to minimize the risk of cavitation.
In this week’s article, we covered the topic of cavitation, which significantly affects hydraulic systems. See you in our next post!