排水辅助减压型真空式鱼泵研究

在分析国内真空式鱼泵样机现有不足的基础上，运用增大真空容积制造负压的原理，试制了抽气、排水相结合减压的改进型鱼泵样机。程序计算及鱼泵样机抽吸活鱼试验结果均表明，虽然真空泵抽气效率不稳定，导致真空罐内压强的实际曲线出现一定波动，但实测曲线与理论曲线趋势基本一致。水泵开启前后罐满时间增加约10s，吸鱼管流速有显著提高，水泵排水对辅助真空泵减压、延长抽吸时间和减小设备体积等均有积极作用。预抽压强为2mH2O时能获得较4mH2O时更短的罐满时间和更高的吸入流速。以150—180mm的鲫鱼为抽吸对象，罐内初压为4mH2O时，20s内可抽上13kg鱼，预计样机1hr内可抽吸约2t的成品鱼。

The study on the water-discharging pressure reducer vacuum fish pump

Based on analysis of the defects of home-made vacuum fish pump, an improved new machine with dual-vacuumizing method of discharging both air and water was designed and made, for the principle of creating vacuum by increasing vacuum space was widely applied at home and abroad. According to the program processing results and technical parameters of vacuum pump and water pump, fish pump was assembled and tests of pumping live fish were carried out in a pool. It was indicated that the curve of pressure variation in the tank fluctuated a little due to unstable discharging efficiency of the vacuum pump. However, the trends of both experimental and theoretical curves were almost same. Suction time with water pump ON was about 10s longer than that with pump OFF, which showed that the flow velocity in the suction pipe increased markedly. Therefore, the method using water pump to discharge water was effective to cooperate the vacuum pump to reduce the tank pressure, prolong the suction time and reduce the machine size. Shorter suction time and higher suction velocity could be obtained when initial tank pressure was set at 2mH_2O compared with 4mH_2O. 13 kg live fish (body length 150-180 mm) was pumped within 20 s by this pump and 2 t fish might be caught within 1 hr.