What is the Link-Seal System?


Link-Seals are a mechanical seal that are supplied in a belt form with a series of interconnecting rubber links, pressure plates & bolts that when tightened create a gas, air & watertight seal between the pipe & core hole (Annular Space).

Link-Seals are considered to be the premier method for permanently sealing the annular space between the pipes & penetrations of any size and the walls, floors or ceilings they pass through. In fact, any cylindrical object may be quickly, easily and permanently sealed, as they pass through barriers, by the patented Link-Seal modular seal design. Link-Seal Modular Seals can seal pipe penetrations ranging in size from 10mm to 3.6m diameter.

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Specially formulated to withstand attack from ozone, UV, water, hydrocarbons and a wide range of chemicals, Link-Seals are available in liquid, gas, oil, temperature & fire resistant models. With a wide variety of hardware/ elastomer combinations, Link-Seal modular seals are easily configured to achieve the best possible match for service conditions encountered. High temperature seals, fire seals (Factory Mutual Approved) and oil resistant seals may be ordered to meet special or unique service applications. Link-Seals are also available for a wide variety of special applications including:

  • temperature extremes
  • exotic chemical combinations
  • slightly “out of round” or non-centered installations.

Link-Seal can be use in combination with Century-Line Sleeves, Steel Sleeves, External Divided Sleeves and Cell-Cast Interlocking Hole Forming Discs and can also be installed directly into core penetrations.

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The Link-Seal Models

Link-Seal® Mechanical Seals, Model “O-S316” (Nitrile)


The Model “O” is resistant to oils, fuel and many solvents (gasoline, motor oil, kerosene, methane, jet fuel, hydraulic fluid, water, etc.), but it is not U.V. resistant so should not be left exposed. The O-S316 model uses stainless steel hardware, which makes it suitable for highly corrosive environments.

Color: Green
Type: Oil Resistant
Seal Element: Nitrile (Green)
Pressure Plates: Composite
Bolts & Nuts: 316 Stainless Steel
Temp. Range: 40 to +210F. (4.4C to +99C.)*

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Link-Seal® Mechanical Seals Model “T” (Silicone)


The high temperature Link-Seal (Model-T) has a 2hrs fire rating according to Australian Standards 1530.4 and 4072.1 and can be used to provide a fire rating but also to provide a positive hydrostatic seal against water or gas at the same time.

If a fire rating is required when sealing against hydrocarbons please contact Projex Group for correct combinations and installation procedures.

Color: Grey
Type: High/Low Temperature
Seal Element: Silicone (Grey)
Pressure Plates: Steel Zinc Dichromate
Bolts & Nuts: Steel with 2-part Zinc Dichromate & Proprietary Corrosion Inhibiting Coating
Temp. Range: -67 to +400F. (-55 to +204C.)*

High temperature seals should be used with Model WS Steel Sleeves.

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Link-Seal® Mechanical Seals, Model “L” (Low Durometer EPDM)


The Low Durometer Model “L” is excellent for use with thin wall metal pipe, applications using plastic, ceramic or glass pipe – or applications where the cylindrical object is fragile and may not withstand the compressing forces generated by a standard Link-Seal® Mechanical Seal.

Color: Blue
Seal Element: EPDM
Pressure Plates: Composite
Bolts & Nuts: 316 Stainless Steel
Temp. Range: -40 to +250F. (-40 to +121C.)*

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Link-Seal® Mechanical Seals, Model “C” (EPDM)


The Model “C” is suitable for use in water, direct ground burial and atmospheric conditions. It provides electrical isolation where cathodic protection is required. Because it uses stainless steel hardware it is excellent for applications such as chemical processing and waste-water treatment. EPDM rubber is resistant to most inorganic acids and alkalis and some organic chemicals (acetone, alcohol, ketones). It can be used in a cored or formed hole or in conjunction with Century-Line Sleeves, Cell-Cast Discs or WS Steel Sleeves.

Color: Black
Seal Element: EPDM
Pressure Plates: Composite
Bolts & Nuts: 316 Stainless Steel
Temp. Range: -40 to +250F. (-40 to +121C.)*

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*= For all Link-Seal models, sustained operation near temperature limits may affect life expectancy

Benefits in using the Link-Seal® Mechanical Seals:

  • Positive hydrostatic seal – rated to 5 Bar – 500KpA
  • Model-T_Fire-rated-application2 hours fire rating (AS 1530.4 & 4072.1)
  • Handles extreme temperatures (-50 to 204 Celsius)(Model T)
  • Chemical, hydrocarbon and temperature resistant
  • Maximum protection against corrosion, 316 stainless steel fittings (except on T models)
  • Mechanical Seal – Can be adjusted and re-fitted
  • Long seal life
  • Can be installed while liquid is running through
  • Handles slight pipe movement
  • Maintenance free after installation
  • Easily installed by one person/contractor – only hand tools required
  • Saves time & money
  • No curing time required
  • Install in up to 75% less time compared to lead-oakum joints, hand fitted flashings, mastics or casing boots.
  • Rated at 20 psig (40 feet of head), which exceeds the performance requirements of most applications.
  • ISO Quality Assurance & manufactured in an ISO 9001:2000 certified facility.
  • 16 sizes, colour coded EPDM, Nitrile, & Silicone elastomers may be used with various hardware options to match performance characteristics with service conditions.

Whenever a pipe penetration needs to be sealed, Link-Seals will get the job done

Link-Seals are the most robust and versatile sealing method available and can be used in most applications and industries, including:

  • Water, waste-water, and drainage
  • Energy production
  • Marine Situations including ships
  • Oil & gas

In all the above Link-Seals applications, one thing is constant: Link-Seals are easy, quick and safe to install and only require one contractor with standard tools.

Why is it that site engineers and maintenance contractors prefers to install the Link-Seals?


Over the years the team at Projex has worked with many designers, engineers, project managers and contractors in specifying and supplying Link-Seals for water and waste treatment plants, desalination plants, oil refineries, gas plants, hospitals, and sewage plants throughout Australia.

Here are just of some of the reasons why Link-Seals are their preferred choice:

  • If a leak occurs at any time in the future due to excessive pipe movement, the Link-Seals can be tightened to stop the leak.
  • If another pipe of the same diameter as the original pipe is then installed the original Link-Seals can be re-used to seal the penetration.
  • Installation times are significantly less than alternative methods.
  • If at any time in the future the pipe needs to be removed it is only a matter of loosening the Link-Seals & removing the pipe
  • Minor pipe axial movement can occur without breaking the seal.

Projex Group has built strong relationships with their clients and provides quality products and service. The Link-Seal® Mechanical Seals have proven their durability and are known to be a trusted, tested & long-term solution.

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Most Common Questions

Q: What do you do if a leak is detected after installation of the Link-Seal mechanical seal?

Unlike other sealing methods you don’t have to empty the tank and/or remove the Link-Seals. Link-Seal is a mechanical seal, so just tighten the bolts & nuts to compress the rubber until the leakage ceases.

Q: Can Link-Seal be used with any type of pipe, even pipes that are not listed in the standard published charts?

Yes, from ductile iron to pre-stressed concrete to metal or plastic pipe, or conduits – whatever your application – Link-Seals will effectively seal between the pipe and the penetration through which the pipe passes. The only exceptions are steel pipes with external spiral welds and severely out-of-round pipes.

Q: How much angular pipe movement will Link-Seals allow and still maintain a seal?

Link-Seals will allow some angular pipe movement or misalignment depending on the ratio of annular space of the penetration to the expanded range of the Link-Seal model sized for the penetration.

Q: Do you need any special tools to install the Link-Seals?

Link-Seals are easy, quick and clean to install. You need no chemicals and no special tools are required, only an Allen key or a hand-wrench and socket.

Q: Should you grout over or seal over Link-Seals?

Link-Seals do not require any assistance to create a watertight seal. However, if a filler is specified (to fill the void in front of the Link-Seals) it is recommended that a separation layer (tape, backing rod, foam) is placed over the Link-Seal bolt heads prior to the placement of the filler should access to the Link-Seals be required in the future.

Q: Can Link-Seals be Retro-Fitted and when is the recommended time to install Link-Seals?

Yes, Link-Seals are suitable for both new works and retrofit situations. Link-Seals are installed after the pipe has been placed into position. Always install Link-Seal modular seals prior to any final connections. This helps prevent off-center pipe alignment.

Projex Group, member of WIOA

Projex Group, member of