Tips for Avoiding Pump-Seal Failure

Unplanned pump downtime often results from premature failure of the mechanical seals. The seals, responsible for restraining product leakage, require tender-loving care that often includes attention to preventive maintenance practices.

A recent blog from California-based Pump Engineering Co. offers three pieces of advice for ensuring that mechanical pump seals perform as designed.

1. Proper Installation

Mechanical seal failures are the primary cause of pump downtime. When installing mechanical seals, follow the manufacturer’s guidelines and handle the seals with care to prevent damaging seal faces or O-rings. Mistakes commonly made:

• Failing to tighten the set screws before removing the setting clips;

• Failing to tighten gland bolts evenly; and

• Damaging O-rings or seal faces.

2. Preventing Excess Heat Generation

Mechanical pump seals come in a variety of sizes and styles, and offer varying ranges of operating pressures and temperatures. For example, here’s a model from Applied Industrial Technologies, detailed at Engineering360, which features an operating pressure of 75 PSI and an operating temperature range of -40 to 225 F. Similarly, this seal from EnviroPump and Seal, Inc., provides an operating pressure of 400 PSI.

Excess heat, most often resulting from dry running, will diminish seal life. And, if pressure in the seal chamber exceeds that recommended by the manufacturer, the seal may need to be altered. Further, if the process fluid cannot properly lubricate the seal faces, reconsider the sealing solution based on the application. Lastly, optimize seal performance by ensuring that the correct piping system is in use, the pump has been properly prepared and its functions fall within the manufacturer’s parameters.

3. Properly Store the Seals

The delicate nature of mechanical seals requires that they be properly stored to prevent damage or failure. Some basic guidelines:

When storing a mechanical seal for more than two years, disassemble the seal and store the individual components. If the seal has been in use, clean and dry the components before storing them. Plug all openings in the seal’s gland; do not store seal faces together in the same packaging.

When storing new seals for less than two years, place them in a clean, cool environment. Every three months, rotate the seal’s faces against each other by two turns, to prevent face lock and loss of face flatness.

Here are the recommended environmental conditions for storing mechanical seals:

• Room temperature—40-80 deg. F, with humidity less than 70%

• No exposure to radiation or sunlight

• No exposure to contamination from solvents, oils, copper or pumped products

• No exposure to ozone or ozone-generating devices or equipment