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Gas-lubricated Mechanical Seal or
Dry Gas Seal

The mechanical seal style GFR/GFL offers a number of benefits over liquid lubricated dual seal for API plans 53 and 54. These include lower maintenance costs for the seal and support system since there is no barrier fluid to fill and the ability to retain 100% product purity through the use of nitrogen as a lubricant.

Dual Cartridge Mechanical Seal Designed to Run Dry with Gas Lubrication



How the Flexaseal GFR and GFL Operate

  • Inert gas enters in the wide, deeper grooves on the OD of the rotating seal ring face.

  • As the shaft rotates, the gas compresses as it passes through the narrowing of the seal ring’s spiral grooves.

  • The resultant gas film pressure provides an opening force slightly greater than the net closing forces, which cause the faces to separate and not contact.

  • Advantages of non-contacting dual gas seal versus a liquid-lubricated dual seal for API 682 Plans 53 and 54:

  • Extended seal life due to non-contacting seal faces eliminating friction and wear

  • Non-contacting faces significantly reduce the amount of heat buildup at the faces, external cooling is not necessary

  • Designed to run dry; excellent for batch run operations like tank unloading when operators neglect to shut pump down

  • No pumping ring is necessary to circulate barrier fluid

  • Simple support system – utilizes API 682 Plan 74 instead of more complex Plans 53 or 54, lowering the cost of operation and maintenance of the seal support system

  • Zero emissions just like seals using a pressurized liquid barrier fluid system

  • 100% product purity: Nitrogen is clean and inert, eliminating product/barrier fluid compatibility issues

  • Reduced power consumption


Materials of Construction

Faces:  Premium grade resin impregnated carbon, sintered silicon carbide

Elastomers:  Viton®, Aflas®, nitrile, ethylene propylene, neoprene, and perfluoroelastomers

Metallurgy:  316 SS (standard construction). Also available in Hastelloy® C276

Springs:  316 SS

Operating Parameters

Size:  1 3/8″, 1 3/4″, 1 7/8″, 2 1/8″, 2 1/2″, 2 5/8″ Standard and Big Bore Options

Temperature:  Up to 390°F (200°C)

Speeds:  1450-3600 RPM

GFR:  Clockwise Rotation (suitable for all ANSI B73 pumps)

GFL:  Counter-Clockwise Rotation


Min. Barrier Gas Pressure: 87 PSI (6 bar)
Max. Barrier Gas Pressure: 180 PSI (12.5 bar)
Barrier Gas Pressure must be maintained
45 PSI (3 bar) above seal chamber pressure

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