Smoother running for process pumps

Innovation is often key to the smooth running of process pumps, as two recent projects – by Axflow and Pruftechnik – demonstrate.

AxFlow faced a problem with certain ring-type vacuum pumps on a solvent recovery system at Solvent Resource Management in Knottingley. The pumps enable scraped film evaporators to boil off the liquid at lower temperatures. However, the packed gland sealing arrangement that came with the Nash SC Series pumps required replacement almost every nine weeks, requiring costly shutdowns.

AxFlow recommended its GLK liquid ring cartridge mechanical seals with carbon/silicon faces and Kalrez O rings to withstand the aggressive nature of the solvents - and supplied with a clean water flush arrangement. The savings made on maintenance and downtime enabled SRM to recoup its investment within six months.

Industrial maintenance company Pruftechnik, meanwhile, has developed a monitoring device to prevent cavitation, which can cause serious erosion to pump impellers, particularly in centrifugal designs, when cavities and bubbles form in low pressure areas of liquid. Vapour bubbles not only reduce the rate of liquid delivery, but they then implode in areas of higher pressure, causing pressure surges.

Pruftechnik has worked with pump makers to define the frequency ranges in pump vibration spectra that relate to the various types of cavitation. The data has been used in the development of its Vibnode online monitoring equipment to detect and alarm at the onset of any cavitation.