Cavitation

The phenomenon of cavitation which can occur in hydraulic pumps on golf courses, consists of the vaporisation of water in the delivery area, whereby the water is vaporised and the bubble implosion The pump impeller is very significantly damaged by the generated vapour cavitation.

This is the result of a poorly designed or malfunctioning hydraulic system. The reason for this is that a minimum pressure, called NPSH (Net Positive Suction Head), is not achieved at the suction, which depends on the individual pump (according to the pump characteristic curve). In the suction process, we must ensure that the pressure loss that may occur does not result in a value lower than the nominal NPSH.

We have always understood that water boils at 100 ºC in nature as we know it, i.e. at 1 atmosphere, but when these drops in pressure occur in pumping, the water boils at abnormally low temperatures, this is cavitation and produces very significant damage, a reduction in flow rate and lower performance.

Cavitation can occur in the eye of the suction impeller, the vacuum pockets appear in the centre of the impeller, which is the area of lowest pressure, and move until they implode or collapse. It can also occur in the scroll or impeller cutwater, a situation that occurs when the discharge height is too high, displacing the working point to the left and outside the operating curve, this cavitation being even more damaging than the suction cavitation.

Detection is achieved by listening for a sound like a hammer hitting metal or stones inside. The best form of prevention is the measurement of the pressure in the suction and discharge, as well as the measurement of the working speed. Gaseous cavitation can also occur, where gases dissolved in water form these bubbles.

There are systems that aim to protect and ensure that the pumping system is in optimum condition. Rigometer is the system developed by Tiloom that allows you to know at all times the energy costs, the pressures at key points of the system and to fully monitor the quality of the irrigation water you use.

Intelligent pumping