... --sealing 2.self --control 3.self --priming pump Features:Property:WFB series non - sealing self - control and self - priming ... medicine, food, electroplating, environmental protection, fire fighting, municipal services, water clean, national defense industry, textile printing and dyeing ... control valve", achieves "once - priming, life - long self - priming."4.Small vibration, low noise, flexible move, ...