SUBJECT: Preventing premature seal failure 10-5

Here is that three question quiz again. I asked the same questions in a previous paper

Question How do you prevent premature mechanical seal failure?

Answer Find out what is causing the seals to fail and prevent it from happening.

Question How long should a mechanical seal last?

Answer Until the sacrificial carbon seal face wears away.

Question How often do seals wear out?

Answer Less than ten percent of the time.

In paper 10-4 we learned that seals fail for only two reasons:

In this paper we will discuss a few of the reasons that seal components become damaged.

Damage is easy to see. It will show up as corrosion or some type of physical damage.

Do not make it too complicated. If you inspect a failed seal and see no evidence of component damage, then the seal faces must have opened because seals fail for only two reasons.

Too much shaft radial movement, whip, wobble or run out is a common cause of a rotating seal component hitting a stationary part of the pump or a rotating shaft hiting a stationary seal component. When a rotating component hits a stationary component you will see evidence of rubbing or damage.

Here are some of the reasons that shafts are displaced radially from the center of the suffing box:

High stuffing box temperature is another cause of component damage.

Cryogenic or low temperature can also cause damage to a component.

Damage can be caused by high stuffing box pressure.

Other causes of seal damage.

A few things seal manufacturers can do to lessen seal component damage, and prevent face opening:

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