... 2).ISO9001, ISO140001 WFB series of non-sealing self-control self-priming pump is to fill the gaps of the first ... for a variety of long axis of liquid pumps, submersible pumps, submersible sewage pumps and other equipment for the best. 2, ... , self-priming performance, stable and reliable, in particular, used the term "electric air control valve", truly a "one-draining, life-long self-priming." ...