Environmental controls for difficult sealing applications

The easiest way to prevent many unplanned premature seal failures is to use balanced o-ring cartridge designed seals. Most of the seal manufacturers make models incorporating these design features.

Rarely is a balanced o-ring cartridge seal supplied as standard equipment with a new pump. It's thought that they cost too much and will raise the sale price of the pump.

Although the balance feature, o-rings, and the cartridge concept were discussed in detail in the previous chapter, here is a brief review why this seal design will give your pumps their best chance for extended leak-free service with reduced maintenance costs.

■ Balance - indicates less heat generated. Heat is the principal enemy of all mechanical seals. There simply is no logical reason for specifying unbalanced seals.

■ The O-ring - is the most widely available and inexpensive elastomer seal in the world. Practically all rubber compounds are available in an o-ring configuration. You can buy them from specialty houses or from the corner hardware store.

■ The Cartridge Concept - has every component part of the sealing system in one unit. They're easier and faster to install and don't require total pump teardown. Most come with additional control ports and rebuild kits.

For most applications, the balanced, o-ring cartridge seal will adequately handle every pump, liquid, and condition in a modern industrial process plant. There are, however, some industrial pumping applications that will present problems to even the best of mechanical seals. Should one of these applications cause the seal to give less than desirable performance, the next step to take in extending the service life of the seal (and ultimately the pump) is to install some type of environmental control to protect and isolate the seal components from the fluid. Let's consider some difficult sealing applications.

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