Paper Company Pump Seal Water Filtration

PUMP SEAL WATER FILTRATION


V-SERIES AUTOMATIC FILTERS

  • All stainless construction
  • Uninterrupted flow
  • 50 micron high capacity screen
  • Lowest backwash volume available

Mechanical seal life can be maximized by filtering the seal water injection system. Here is how one company saves money by doing just that.

The Nexfor Fraser Paper Company in Berlin, NH makes fine paper, toweling and machine dried hardwood kraft pulp. The mill recently installed a new pulp screening line to improve output and efficiency. The pumps and pressure screens in this new line are equipped with mechanical seals.

Source water for the seals comes from a river, which at times, can contain a great deal of sand and silt. Since the biggest cause of mechanical seal failure is dirty seal water, it was necessary to filter the water supply trapping particles above 50 micron. The existing sand filters were not capable of doing this with reliability.

Mike Perreault, the Pulp Mill Maintenance Superintendent, asked Pete Longley with Industrial Packing of Bucksport, ME if he could come up with a solution. Pete turned to VAF of Denver, CO for a recommendation.

VAF recommended a stainless steel automatic screen filter with a patented dirt collection system - model V-125-2-50. Nexfor Fraser had it's own mill control system, so the filter was designed to utilize a PLC in the existing system for flush control. A differential pressure (DP) switch senses the build up of dirt on the 50 mic screen and opens a flush valve when the DP reaches 7psi. Complete cleaning of the screen is accomplished in about 15 seconds and uses only about 3 gallons of flush water. The cleaning mechanism uses line water pressure for it's only source of energy. Flow to the seals is not interrupted when the filter is flushing. The PLC closes the flush valve when the cleaning cycle is complete.

Nexfor installed the first filter in mid 2003. The operation was very successful and the company ordered a second filter later that year. This is a critical service installation, so reliability as well as filter efficiency were factors in filter selection. Replacing a mechanical seal is costly in plant down time, maintenance cost and parts cost. The resulting extended seal life has a favorable impact on the plant's maintenance budget and the plant's bottom line.

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