Eight, what is NPSH? What is the suction? Each unit of measurement that letter? When the working fluid pump at the inlet of the impeller due to a certain vacuum pressure will produce vapor, vaporized liquid bubbles in a particle collision sport, impeller and other metal surface erosion, undermining the impeller and other metal, NSQ100-50-37 pumping sand pump, when the vacuum pressure is called the vapor pressure, NPSH means a surplus of energy in the pump suction port unit exceeds the weight of the liquid has a vapor pressure. Units with meters marked with (NPSH) r. Suction is the NPSH Δh: namely liquid suction pump allows a degree of vacuum, NSQ300-15-30 pumping sand pump, that pump allows installation height, Yantian District N, units in meters. Suction = standard atmospheric pressure (10.33 m) - NPSH - Security amount (0.5 m) standard atmospheric vacuum pressure pipe 10.33 meters height. For example: a pump NPSH of 4.0 meters, seeking suction Δh? Solution: Δh = 10.33-4.0-0.5 = 5.83 米 early in 1588 there will be a record about 4 blade vane pump, one after another appeared in a variety of other rotary pump. In 1689, France D. Papin invented a 4 blade impeller centrifugal pump volute. In 1818, the United States appeared in a centrifugal pump with radial straight blade, semi-open double-suction impeller and volute. 1840 ~ 1850, NSQ400-15-37 pumping sand pump, the United States of HR Worthington invented the steam directly acting piston pump the pump cylinder and steam cylinder opposed, marking the formation of the modern piston pumps. 1851 ~ 1875, multistage centrifugal pump with guide vanes have been invented, so the development of high-lift centrifugal pump as possible. Subsequently, various pumps after another. With the application of advanced technology, the efficiency of the pump gradually increase the scope and application performance are increasingly expanding. NSQ400-15-37 pumping sand pump sand suction submersible pump (Online) | Yantian District by Shijiazhuang-Pump Co., Ltd. faction. Shijiazhuang-school Pump Co., Ltd. (www.shipaipump.com) is Shijiazhuang, other leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Pump in Shijiazhuang-school leadership with the staff warmly welcome all inquiries negotiations to create the Shijiazhuang-pump send a better future.