Design And Research Of Cascade Pumps In Frequency Conversion Water Supply System

As a power transmission device for water,water pumps have been widely used in many aspects of the current society.In the current water supply system,most of the pump units use multiple pumps in parallel to configure the frequency control mode.During the parallel operation of the water pump,as the demand for water increases,the number of pumps runs gradually increases,and the flow rate increases gradually,the hydraulic loss in the sump gradually increases,and the operating efficiency of the system decreases.In view of the above problems,this paper proposes to configure the pump unit with the flow rate corresponding to the flow rate in the high-efficiency area at the rated frequency as the step-by-step continuous condition,so that the pump unit always has only one single operation,combined with the operation mode of frequency conversion speed regulation,to solve the gradual increase of the number of pumps running.The problem of decreasing traffic volume and system efficiency is reduced.With the change of water demand,the pumps of different flow levels are automatically replaced and always operate in high-efficiency zone,reducing energy consumption.The main research contents are as follows:1.This paper analyzed the operation characteristics,operating condition points and adjustment modes of the pump,and analyzed and studied the energy saving principle of the cascade configuration of the pump.2.Determine the optimal working area of pump frequency conversion operation according to the efficiency curve of pump frequency conversion.3.Determine the high-efficiency zone for the operation of the pump according to the performance curve of the pump,and configure the pump under the constraint that the flow corresponding to the high-efficiency zone is cascade continuous.4.Design an intelligent pump selection system based on Java programming language.Design intelligent cascade pump selection software under the constraint that the high-efficiency zone is cascade continuous.5.Designed an automatic check software for pump operating point based on VB,and checked and calculated the model of cascade configuration pump selected by JAVA pump selection software.6.Set up the experimental platform according to the design and operation scheme of the cascade water pump proposed in this paper and conduct the test research.The experimental results show that,when the pump outlet valve is fully open and the system frequency conversion range is 80%?100%,and the flow range is 4-8 m3/h,the actual operation efficiency of the cascade configuration scheme is about 5%higher than that of the traditional parallel configuration scheme.Within the flow range of 8?11 m3/h,the actual operation efficiency of cascade configuration scheme is about 11%higher than that of traditional parallel configuration scheme.Within the flow range of 11?14 m3/h,the actual operation efficiency of cascade configuration scheme is about 15%higher than that of traditional parallel configuration scheme.Within the flow range of 14?16 m3/h,the actual operation efficiency of cascade configuration scheme is about 20%higher than that of traditional parallel configuration scheme.Compared with the traditional parallel water pump sets,the cascade water pump sets with high efficiency have obvious energy saving effect.