Third, to reduce the existing pump cavitation damage methods 1, into the pool at the site of use, the occurrence of cavitation (including other failures) of the pump to view the flow of water into the pool is very necessary and convenient. If the pool surface can see a strong vortex, should consider adding broken vortex. In addition, the nozzle and the sink geometry should also be noted. Such as: nozzle from the pool wall is appropriate, whether there is a bubble into the pump suction tube. Note that the pool water level is necessary to raise the water level into the pool can reduce or completely prevent cavitation. Jietai pumping station on the water inlet transformation, erosion reduction of about 45%. Qilu Petrochemical Liu Kewang, Sun Jinghe and others in the import of circulating pump inlet vortex after the pump no longer occurs and the flow from the unstable 8500, 8000m3 / h, respectively, increased to a stable 9700,8200m3 / h. 2, Inlet pipe inlet pipe set In addition to the pipeline should try to make small losses (such as the minimum number of elbows and unnecessary valves), let the inlet pipe may not have higher than the pump inlet parts to prevent the tube of gas. Chishui Natural Gas Fertilizer Plant in 1995 circulating pump imported rubber expansion to 1000mm, while the pipe is 800mm. To this end an increase of the exhaust pipe to solve the pressure drop due to its resistance to solve the cavitation problem. 3, adjust the pump flow Wang Weidong, Xinjiang Electric Power Design Institute suggested that the original resistance calculation formula used in our country from the former Soviet Union, the calculated resistance value is larger than the actual, resistance calculation should adopt the new formula. Otherwise, the pump is prone to cavitation at high flow rates (Northwest Power Technology 2000). In the pump design selection and the actual deviation, the pump cavitation and economic operation can be solved by cutting the impeller, in order to achieve the purpose of eliminating cavitation and operating economy, this practice has proved to be effective. 4, the use of injection structure injection device in principle equivalent to the liquid - liquid jet pump. A high-pressure water is drawn at the pump outlet into the high-pressure water chamber as shown, and high-pressure water enters the suction pipe of the pump through the annular nozzle. The high-pressure water is mixed with the water in the suction pipe to exchange energy, and the energy of the mixed water after mixing is increased relative to the water energy of the original suction pipe so as to meet the required NPSH margin of the pump inlet. Zhejiang University, Wu Yu, who introduced this (Zhejiang University master's degree thesis 2003), the paper describes the lead injection device back flow should be controlled between 2% -5%. Mr. Zhang Dehuang used a similar method in Changsha to test the multi-stage pump with 100 caliber and achieved remarkable results. The method is to use 1/2 of the tube after the balance of water led to the pump inlet, pump system, the device NPS decreased by 0.5 ~ 0.8m. Guo Dilong, Wuhan University, who introduced a jet - centrifugal pump device. This device is equivalent to the jet pump and centrifugal pump in series work on the suction pump is very effective, but generally not suitable for the pump in service transformation. 5, imported qi qi gas method does not prevent the cavitation cavitation, but the qi will be appropriate to reduce the bursting holes on the runner wall damage, fill the gas as a protective runner wall sponge. This method is commonly used in water turbines and the like, but very little use is made of gas supplementing the pump due to the difficulty in grasping the gas supply. Wuhan University of Water Conservancy and Electric Power Sun Shou, Yan Jinwen on the water vapor pump waterproofing research and achieved some results, but also pointed out: gas pump cavitation prevention and control, highly technical, only the gas flow, qi location and qi Way to negotiate, in order to achieve good results. Otherwise, the flow, lift and efficiency of the pump will drop a lot, causing adverse consequences.
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