LineBacker® 61 NSF Certified Sealing & Isolating Gasket, by GPT

LineBacker® 61 NSF Certified Sealing & Isolating Gasket, by GPT
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Benefits / Features
  • Eliminates flange leaks.

  • Guards against blowouts.

  • Usable with any type of flange or combination of flanges.

  • Lowest possible clamp and compressive load to effect a seal.

  • Insulating version is both a positive seal and a superior isolator.

  • High dielectric strength.

  • Water absorption less than 0.10%.

  • All standard ANSI and API flange sizes from 1/2" and above.

  • Temperature Range: Cryogenic to +280°F. (+138°C.)


LineBacker® sealing gaskets utilize a rectangular sealing element, referred to as a “quad” ring, in combination with a unique groove design to effectively seal and isolate flanges for all types of applications. Used and proven, for over 40 years, in the water and energy industries, LineBacker® gaskets have been effectively sealing flanges within piping systems carrying potable water and other fluids at high/low temperature extremes and at high pressure ratings.

Of particular importance with respect to NSF/ANSI Standard 61 is the micro-exposure of the sealing element (EPDM) within the G-10 Epoxy Glass retainer material. In addition to providing positive sealing characteristics relative to the fluid flowing within the pipe, the seal element is also protected from deterioration by atmospheric conditions, which dramatically lengthens the service life of the gasket.

NSF/ANSI Standard 61 establishes minimum health effects requirements for the chemical contaminants and impurities that may be indirectly imparted to drinking water.

The LinkBacker® 61™ Sealing/Isolating gasket meets all criteria associated with NSF health effects testing, certification and production facility inspections. GPT’s registration confirms that NSF has assessed and certified the LineBacker® 61™ as conforming with the relevant NSF standards. For more information regarding NSF, visit

Before Tightening

The sealing elements extend slightly above the surface of the retainer. As the flange is tightened the sealing elements are compressed and move sideways into the inclined portion of the groove, developing a high unit pressure against the flange faces.
After Tightening

The flange faces have come into firm contact with the retainer, thus encapsulating the sealing elements within grooves. At the same time, the unique LineBacker seal configuration provides elastic memory for elastomers not normally associated with this characteristic - resulting in a simple flat gasket with extremely high loading and self energizing characteristics without adverse cold flow problems.