水泵选型与运行模式对变频调速供

从离心水泵工况分析入手，研究了变频调速恒压供水系统中水泵的适用性问题，给出了保证系统高效运行的水泵选型控制参数。在水泵选型和运行调度都合理时，变频调速供水系统才可取得预期的节能效果，小流量条件下需辅以气压给水技术节能。为充分利用高效率调速运行的流量区间，设定的工作压力应等于或略大于所选水泵高效区右端点的扬程。同型号水泵并联工作，只对1台水泵调速时，调速泵仍然存在小流量供水现象；设定工作压力下单泵最大供水量大于高效调速区间下限流量的2倍时，对2台水泵实施调速可避免水泵工况点偏离高效区。

Influence of Pump Type-Selection and Operating Mode on Energy-Consumption of Frequency-Conversion and Speed-Adjusting Water Supply System

Based on the analysis of operation condition of centrifugal pumps, the applicability of frequency-conversion and speed-adjusting water supply system was studied, and main parameters for type-selection with high operation efficiently of the system were proposed. The expected energy-saving effect of the system could be obtained when the pumps were selected and operated reasonably, and the pneumatic tank should be used when water supply discharge is small. In order to take full advantage of the quantity range with higher efficiency, the given pressure should be equal to or slightly higher than the head of right end of characteristic performance curve in high efficient area. In the system of parallel connection of same type pumps and only one pump was controlled by frequency converter, the speed-varying pump may still operate inefficiently because of small quantity. If the maximal water supply quantity of one pump under given pressure is more than two times of the minimum water supply quantity in the high efficient range, pumps can operate without deviating from high efficient area by means of controlling two pumps with frequency converter.