Plunger pump seals - How little $2 parts can be a major headache for operators

My name is Christian Dillstrom and the last ten years I have been a global growth hacker. I am also a business author with over 24 million readers, so I know the value of expert advice.

I have clients from many, many different industries. Today, I am learning about plunger and multiplex pumps which are, for example, used in the oil&gas and water industries.

I’m always looking for new insights, so I am very pleased when I encounter professionals like Joe Bichler, a pump expert from Grand Rapids, USA. The topic of this article series is plunger pumps and how to foolproof and maintain them for best performance.

Hello again Joe!

Today, we talk about pump seals.

In our first interview you said that most plunger pump problems have cheap solutions.

Do you have an example?

Everything was tested out in the shop and everything was perfect.

A few years ago I was installing a plunger pump that had been 100% rebuilt. Everything was new except the empty power frame and the empty fluid end cores. Everything was tested out in the shop and everything was perfect. We were ready to deliver! We shipped it and thought everything was OK. It wasn’t. The customer installed the pump and it was malfunctioning.

No one could figure out why it was malfunctioning.

It worked to a point but when it neared its operating pressure it began to vibrate excessively. No one could understand it. We tried everything. We finally sent a service technician across the county to pay our customer a visit thinking it would be a quick fix. After 12 hours of work and doing everything by the book it was midnight and the pump was still vibrating.

Then the technician found a very small crack in the nitrile rubber of one of the rings.

None of this made sense. Everything was new and factory spec. Finally our service tech took all of the cylinder and valve covers off as well as the stuffing box packing and thoroughly inspected each seal. They were all new. Each looked good.

It wasn’t until he started to bend the O-rings from the cylinder covers that he found a very small crack in the nitrile rubber of one of the rings. The crack was about 1/3 the thickness of the ring and it was totally invisible until the ring was distorted.

That was the problem! A $2 O-ring!

He replaced it and to everyone’s surprise the pump began working as it should! As simple as this fix was, it was a hard lesson to learn. A small crack in a brand new seal caused a lot of wasted time, energy and grief. We all learned a very valuable lesson.

I am convinced that proper sealing of a fluid end cylinder can prevent most of the maintenance issues associated with these kinds of pumps!

Multiplex pumps have many seals in them: Cylinder head seals, valve cover seals, manifold seals, stuffing box packing and wiper box packing. They are all relatively cheap. If you want to avoid problems with your pumps have plenty of seals on hand and never reuse a seal.

Also, if you open a cover, put in a new seal. If you over tighten a stuffing box gland and a rod gets too hot or scored, replace the packing and be more careful when adjusting it in.

Thank you Joe for this interview!
We will continue with the next article and zoom in on other problem solving solutions with pressure gauges and other fail-proofing hints for plunger pumps.