The pump is based on our original Ⅲ type circulating water pump on, according to the college student experiments and test requirements, the use of negative pressure jet principle designed a four-tap, double-sided more with the same pump, even if the teacher is demonstrating Students may at any side of the boot, shutdown. Widely used in evaporative distillation, crystallization, filtration, vacuum sublimation and other operations, is the ideal device universities, pharmaceutical chemicals, food processing and other areas of the laboratory.