Reliability And Future Development Of High Pressure Diaphragm Pumps For Process Service
The aim of pump development in recent years has been mainly reliability, safety, low maintenance, and the avoidance of dangerous leakages. For years, more and more rigid regulations against pollution and for better safety have been issued. Many reaction components have been classified toxic or dangerous, with the consequence of a great trend towards leak free systems. For oscillating displacement pumps, the plunger sealing is difficult due to high pressure, pulsating forces and sliding speed. If ever one finds a satisfactory solution for a difficult plunger seal, there remain the disadvantage of unavoidable low leakage, necessary skilled maintenance and low lifetime. The obvious separation of the pump’s liquid end from the drive mechanism by diaphragms has been realized for years in small metering pumps. The development climbed to increasing power of about 10 kW, so that actually, there is a dominance of the diaphragm towards piston pumps. Recently, the development of very large diaphragm pumps for process service, with power up to 500kW, shows very reliable performances. Together with the total leak-free design the remarkable increase of reliability compared with conventional multiplex plunger pumps is very important. Many difficult fluids, such as abrasive suspensions, nonlubricating solvents or liquids gases can be pumped troublefree at pressures up to 1000bar. For process service, the application of resistant fluor plastomer or metal diaphragms is a mus. The design, calculation, sealing, champing, fatigue, lifetime, and especially the future development, which is expected to reduce the dimensions, are explained. Long term applications have shown that diaphragm pumps actually perform to trouble-and maintenance-free service of many months. The most important step towards total safety was the development of sandwich diaphragm rupture monitoring systems. The hydraulic system and the alternative designs are compared. This has developed towards automatic position-control of the diaphragm. Safety, venting and snifting valves and their control are very important. Some remarks deal with fatigue and wear problems at high pressure of components like thick walled parts and valves, and with design of the drive units and their control. An important condition for reliable service of high pressure diaphragm pumps is the restriction of pressure vibrations in the piping system and avoiding any cavitation. There is a significant influence of fluid compressibility on displacement characteristics and stimulation of pipe vibrations. A computation method including dampers is outlined.
Vetter, Gerhard (1988). Reliability And Future Development Of High Pressure Diaphragm Pumps For Process Service. Turbomachinery Laboratories, Department of Mechanical Engineering, Texas A&M University. Available electronically from