How to avoid cavitation in chemical centrifugal pumps?

　　The main hazards of vapor corrosion

　　(1) cause material damage. Vapor corrosion occurs, due to mechanical stripping in the chemical corrosion of the common role, so that the material is damaged, due to the complexity of the phenomenon of vapor corrosion, so its formation mechanism is still in the research and study until now, it is generally believed that the mechanical stripping caused by hydraulic impact, the first material damage, and is the main factor causing material damage.

　　(2) Produce noise and vibration. Cavitation occurs when the rupture of the bubble and high-speed impact will cause serious noise, in addition, the cavitation process itself is a repeated condensation, impact process, accompanied by a great deal of pulsating force, if the frequency of these pulsating forces and the natural frequency of the equipment is close to the frequency of the strong vibration will be caused by the cavitation caused by the pump rotating parts of the material damage, will inevitably affect the static balance of the rotor and the dynamic balance, resulting in serious mechanical vibration.

　　(3) Make the centrifugal pump performance decline. When the pump cavitation, it will make its performance decline. Pump bubbles less, the pump's performance curve and no significant change, which is the incipient stage of cavitation, a large number of bubbles produced, the flow channel is “blocked”, then the cavitation has reached a developed stage, manifested in the pump's performance curve, there are obvious changes in the performance curve, the performance curve declined significantly, the emergence of the “fracture” condition. Fracture” condition, but different than the speed of the pump, the decline in the performance curve of cavitation is different.

　　Centrifugal pumps are most prone to cavitation parts are:

　　a, the impeller curvature of the largest front cover plate, near the vane inlet edge of the low-pressure side;.

　　b, low-pressure side near the inlet edge of the worm shell spacer tongue and guide vane in the press-out chamber.

　　c, no front cover plate of the high ratio impeller impeller tip of the outer circle and the shell of the tip of the sealing gap between the low-pressure side of the tip and the tip of the impeller.

　　d, multi-stage pump in the first stage impeller.

　　Centrifugal pump cavitation phenomenon how to solve:

　　1, improve the centrifugal pump itself anti-cavitation performance

　　Structural design changes between the impeller and the inlet of the pump.

　　It is necessary to increase the radius of curvature of the inlet section of the impeller cover.

　　The thickness of the vane is reduced, the inlet is repaired flat, as far as possible to get round, streamlined is not prone to vapor corrosion, but also can reduce the head of the winding vane acceleration and decompression.

　　2, improve the effective vaporization margin into the liquid device

　　Improve the pressure of the liquid level in the storage tank before the pump, the margin of corrosion will also be enhanced, which effectively avoid the occurrence of cavitation.

　　Can reduce the installation height of the pump, the installation height should not be too high.

　　Backflow device is more conducive to preventing the occurrence of cavitation.

　　There is also to ensure that the temperature of the medium at the entrance should not be too high.