Will Pierce, engineering manager for Schurco Slurry, recently offered advice for mechanically sealed slurry pumps. For single and double seals, he recommended keeping transient pressure from parallel trains or water hammer from getting to the pump by isolating pumps from independently operating pump trains or consider two check valves to arrest water hammer. “Close valves slowly, and never dead head your pump,” Pierce said.
For single seals in particular, plant operators should ensure the seal faces are getting adequate lubrication and cooling. The flushless styles need open bore stuffing boxes and opened back-liners with impeller back vanes removed or filled, Pierce explained. Flushed seals need seal water delivered at a pressure exceeding stuffing box pressure.
With double seals, plant operators should check on the API Plan 52, 53 or 54 system regularly. They should ensure that barrier fluid is at an appropriate level in the seal pot and check the temperature drop across return and supply lines
to the pot (return goes to the high point, and supply from the low point on the pot), and make sure they’re seeing good temperature drop across those lines. Also the pressurized seal pot system exceeds the pressure in the stuffing box by 10 psi (0.7 bar) to keep barrier fluid just slightly migrating across your seal faces.