{"id":7819,"date":"2020-10-23T15:20:27","date_gmt":"2020-10-23T13:20:27","guid":{"rendered":"https:\/\/www.tempco.it\/blog\/?p=7819"},"modified":"2020-10-23T15:20:54","modified_gmt":"2020-10-23T13:20:54","slug":"how-to-prevent-cavitation-in-centrifugal-pumps","status":"publish","type":"post","link":"https:\/\/www.tempco.it\/blog\/en\/7819\/how-to-prevent-cavitation-in-centrifugal-pumps\/","title":{"rendered":"How to prevent cavitation in centrifugal pumps"},"content":{"rendered":"

Centrifugal pumps<\/strong><\/a> and cavitation<\/a><\/strong>, an extremely dangerous bundle that absolutely has to be avoided. Cavitation is an event that happens when steam bubbles develop within a fluid<\/strong>, which imploding cause a characteristic noise inside the machinery, lowering its performance and damaging its components<\/strong>, such as pumps\u2019 impellers and the pump itself. This is a very common phenomenon in ships\u2019 screws and centrifugal pumps, indeed. Let\u2019s then see what to do in order to avoid cavitation in centrifugal pumps.<\/p>\n

Centrifugal pumps come with characteristic performance curves<\/strong>, the most common ones being the flow rate hydraulic head<\/strong> of the pump, as well as the NPSH – Net positive suction head curve<\/strong>, related to the maximum suction head of the pump. We\u2019re talking about pumps having a NPSH, thus not self-priming pumps which automatically fill themselves sucking water. NPSH pumps have to be filled with water, respecting a suction head not surpassing the indicated NPSH value.<\/p>\n

When forcing a pump operating at a lower suction value, we will surely end-up with cavitation. With cavitation, for example on a ship\u2019s screw, air bubbles develop near the edges of the impeller<\/strong>, reducing the performance and imploding. The same with connection edges of the pumps\u2019 impellers. Vapor bubbles develop when the vapor pressure is surpassed, otherwise when the pressure level decreases so much that the liquid starts evaporating<\/strong>. Let\u2019s bring a basic physical principle here: at atmospheric pressure, water starts boiling at 100\u00b0 C. Putting water in a vacuum vessel, the boiling temperature decreases a lot.<\/p>\n

When a lower pressure area<\/strong> is generated near the pump\u2019s impeller, it will ignite the evaporation of the fluid<\/strong>. Evaporating water causes micro-implosions that damage irreparably the impeller.<\/p>\n

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