ASUBJECT: The problems associated with original equipment mechanical seals 4-4

The next time you purchase a pump, mixer or some other type of rotating equipment and request that it be supplied with mechanical seals, you're going to be very disappointed in the performance of those seals unless you specify exactly which brand, model and materials you want.

If you fail to do this you'll be supplied with a hydraulically unbalanced mechanical seal, manufactured from unnamed grades of materials and you will find that the seal will leak long before the sacrificial seal faces are worn out. In other words, the seal will have plenty of wearable carbon face left when it starts to leak.

In addition to supplying a poor performing seal the manufacturer will attempt to put the seal into a piece of equipment that was designed for soft packing. The result will be less than idealr seal and bearing performance and premature failure of both of them.

What's wrong with these O.E.M. seals? The following paragraphs will describe a few of the problems. The seal that came in your pump was probably supplied with:

Please look at the following diagram.

This diagram describes a rotating "back to back" dual seal with a whole series of problems that include:

What can you do about these problems? The answer is obvious; do not use original equipment seals. Do you remember how you handled the packing that came in pumps? You threw that stuff away and used the type that worked in your applications. Tell your supplier that you want balanced O-ring seals made from proper materials and the material grades must be identified because you chose not to run your facility on "mystery materials".

To insure longer mechanical seal life do the following:

® E.I.Dupont

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