Compressor Seal Replacement: Everything You Need to Know

In many industries, compressors are responsible for the toughest sealing tasks.

Compressor machinery is used in chemical processing, refineries, mining, petrochemical processing, food and beverage, biosciences, and environmental sectors. These industries deal with flammable, corrosive, or toxic media on a daily basis. Such demanding conditions call for compressor seals that are reliable, operationally safe, robust and cost-effective.

Dry vs Wet Compressor Seal

Industries can opt for either a dry or wet compressor sealing system.

In a wet compressor seal, oil is added as a leak barrier and lubricant. Due to this, most of the gas or heat is absorbed and barely any escapes. After some time, flash tanks or heaters are used to de-gas the oil and its added back into the system.

A dry—also known as ‘non-contacting’ compressor seal—is a substitute for the traditional wet seal system. As the name suggests, it does not circulate oil, rather its job is to keep the seal faces apart by either regulating the forces working on the seal faces (hydrostatic) or by addinga film of gas in between (hydrodynamic).

Seal Options for Compressors

Once you’ve chosen the sealing system you need to select one of three seal arrangements in the market. Each has its own unique arrangement and function.

Single Seal

a single mechanical seal

A single seal arrangement is ideal for air or nitrogen compressors as the product leakages here are not harmful to the atmosphere. A tandem seal must not be used in these circumstances at all.

Double Seal

double spring seal

If any product leakage to the environment or flare is completely unacceptable, a double seal arrangement must be used. It is also ideal for low pressure functions. This seals design is mostly found in chemical and petrochemical industries where its used for different equipment, such as the HC gas compressor.

Tandem Seal

a tandemspring

A tandem system is used when nitrogen is not available and a slight amount of gas leakage is tolerable e.g. in gas pipeline compressors. The tandem seal arrangement provides good operational safety. The bearing side has a safety seal on it that acts as a backup and typically runs at low pressure. However if the main seal fails, it can handle full pressure as well.

The process of selecting the right sealing system for your compressor can be very daunting.

Robco of America wants to ease this process for you and provide the best product suited to your needs. We provide pre-made industrial compressor seals used for common models as well as hassle-free mechanical seal repair services for your current compressors. We are also equipped to prepare custom design mechanical seals for any unique requirements you may have.

Contact our team of technical experts today, by calling 1-800-662-0585 or email

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