Maintaining Packing in Your Nash Vacuum Pump
Extending the Meantime Between Failures
The Importance of Maintaining the Packing in your Nash Paper Mill Pump
Bearing Failures: Of course, it always happens on the night shift or weekend: The vacuum pumps tend to get the least amount of attention until one unexpectedly fails . . . and it’s a big deal. They are never in an easy to access location and can weigh up 34,000+ lbs.
Photo: At the Nash owned Rebuild Facility near Birmingham, AL,. Anthony stands next to the largest 904 (U) vacuum pump. 34,000+ lbs each.
Areas of Neglect: The bearing/stuffing box areas probably account for more vacuum pump failures than any other in paper mills. 1) Controlling packing leaks, and 2) Over-greasing/under-greasing.
Packing leaks: Controlling packing leaks is one of the keys to getting the most runtime between failures. Water will try to migrate along the shaft and compromise the grease in the bearing. To mitigate this, Nash will many times install two lip seals and a slinger to prevent water intrusion.
Do bearings like to swim? See for yourself: Below: Article on Maintaining and Adjusting Packing:
Excessive Pulp Carryover: Lastly, another source of issues can come from within the pump: excessive carryover. In this case, the likely culprit is the pre-separator system is under-performing.
Action: Trace the piping back to the pre-separators. As the machine has been upgraded over the years, they are likely undersized, drain clogged with debris, and many times it is the separator removal pump. We can help you diagnose at no charge.
Photo: In a newly installed pump, you can see there is so much pulp carryover it is exiting the packing. This will result in excessive erosive wear to the pump internals
NASH has a solution for all this: The EnduraSeal Upgrade
E.W. Klein never charges for our reports/engineering assistance. Does your vacuum pump rebuilder/supplier do the same for you?
The Dreaded Grease Tunnel: As you can see in the picture to the right, over-greasing can build up and create a “grease tunnel” that can direct the package leakage towards the bearing. Grease will also clog the drain holes meant to collect and drain away the normal packing leakage.
Action: Prevent over-greasing and keep grease trays clear of excessive grease and build up.
Photo: The grease will block the packing drains and many times direct the packing leaks towards the bearings.