How to Select Mechanical Seals for Pumps

Carefully consider applications, pertinent safety requirements, liquid to be transferred, pressure and temperature, and environmental concerns when selecting mechanical seals for pumps.

mounted double seal pump

Published June 28, 2021   |   2 minute read

Small as mechanical seals might be compared to other components in a liquid transfer system, their importance cannot be overstated. When you choose the right mechanical seal, it can operate for years with very little maintenance, and protect your entire system, your plant personnel, and the surrounding environment from leaks and unwanted emissions.

There are hundreds of different mechanical seals on the market, however, each with its own unique benefits and drawbacks. What works for one system might not work for another and could result in significant system disruptions, downtime, and costly repairs.

There are numerous factors to consider before choosing a mechanical seal. Here’s how to select those that will work for your pumps.

Considerations for the Right Seal

Before you start the purchasing process, consider the following:

  • What application will you be using your seal for?
  • In what industry are you operating? 
  • Are there legal requirements and/or industry standards your equipment has to meet?

Beyond these top-priority questions, there are several important characteristics to look for when choosing a mechanical seal.

What kind of liquid will you be transferring?

Make sure you know what kind of liquid transfer you will be handling and how it behaves. Also, be sure to consider all of the liquids the seal may be subject to (i.e. – steam, CIP, caustic or acid wash, etc.).

Why? Not all liquids are created equal. Some are shear sensitive. Some are viscous. Some react differently depending on pressure. Is the fluid caustic? Is it hazardous? What is its chemical composition? 

Some seals are made of materials specifically developed to handle hazardous chemicals that others wouldn’t be able to handle, thus failing and resulting in leaks. Never assume that a mechanical seal will work just because it fits on the pump you’re using!

Pressure & Temperature

Seals perform differently depending on the pressure and temperature of the liquids they’re exposed to, among other factors. Always know what differentials your seal is sensitive to.

Environmental Concerns

Leaks happen. That’s just a matter of fact when it comes to liquid transfer. The type of leak, however – such as caustics, acids or other hazardous materials like petroleum — can result in dangerous working conditions for your employees and cause environmental damage, leading to equipment damage and hefty fines.

Certain mechanical seals can prevent these, though. Look for seals specifically designed to handle volatile substances. Some considerations include:

  • What material is the seal made from? Are the materials compatible with caustics, acids, and other hazardous materials?
  • Is the seal designed to facilitate leak containment in case of an accident or other unforeseen leakage event?
  • Can it handle extreme temperature changes, abrasive conditions, multi-phase fluid properties, and other hazardous conditions?

Work With Experts to Find the Right Mechanical Seal

Mechanical seals are expensive. Be sure you're spending your money on the right technology. The easiest way to select the right model for your purposes is to consult with an expert.

Sunair Co. is the Mid-Atlantic’s industry-leading expert on mechanical seals, pumps, compressors, and more. Our team has been developing custom systems and advising clients on which mechanical seals they need for their systems, across dozens of industries and hundreds of applications, for 50 years.

Contact us today to learn more about how we can help you select the right mechanical seal and other equipment for your needs. 

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