... device", and to eradicate the traditional pump packing seal, packing seals, mechanical seal defects, the total elimination of the "running, ... stable and reliable, in particular, used the term "electric air control valve", truly a "one-draining, life-long self-priming." 4, little ... install, no need to foot fixation. 5, with excellent self-control function, and high-tech areas and supporting the use of ...