Bran Luebbe plunger pump packing failures - Help!

We have a Bran Luebbe reciprocating plunger pump with following parameters:

2" diameter plunger, 3" length of stroke, 60 strokes/min, 1900 psig, 495 degrees F. Plunger is tungsten carbide cladded. Plunger is 10" long.

This is a polymer plant. we are pumping water, then product, then butane diol at above temp and pressure.

product is 70% water, with 30% polymer salt which can be considered abrasive I think...

We are using a base metal ring at front of the stuffing box, and intermediate metal ring like a lantern ring but with no flush in middle of stuffing box, and another metal base ring at back then a metal packing compression ring.

6 rings of braided packing toward front of plunger between front base ring and intermediate ring and 6 more rings of packing between intermediate and back base ring. The 6 back rings of packing are palmetto 1350 kevlar, in the front we have 3 kevlars and 3 GTFE palmetto 1387.

all are precompressed to 2000 psi.

we constantly have to tighten compression ring due to leaks; and have to add a ring of packing at back about every 2 weeks. needless to say; after a few weeks of this, we have to take the pump down and rebuild.

the packing extrudes out into the process. it is braided rope packing.

I am changing the metal rings from nickel 200 alloy to wachasha 88 which is nongalling in hopes that will help some with longevity.

has anyone used hydraulic V-cup seal rings stacked in an application like this? I have been considering using a kevlar Vcup seal ring stack at the back near compression ring where things are cooler.

or can you offer any suggestions that could help!

Thanks to all!!!!!!!!!!!!!!

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[disclaimer] Off-the-top, unconsidered, probably impractical.

Still..... I would like to explore the possibility of injecting pressurized clean water between piston rings, to provide a small net leakage into the product via. No extrusion, wear reduced. There could be a place for o-rinngs, even

Brian W

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Brian Whatcott

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