What is a Link Seal?
Link Seals are mechanical seals that are used to create air, water, or gas-tight seals between a pipe and a core hole. They are available in belt form consisting of a series of interconnected rubber links, pressure plates, and bolts that are used to seal a pipe or cable with a casing sleeve, duct, or wall.
Advantages of Link Seals
Link Seals provide a permanent sealing solution for the annular space between pipes and any size of walls, floors, or ceiling penetrations. In addition, they are proven to be a quick and easy method for sealing any kind of cylindrical object with its penetration barriers.
Applications of Link Seals
Link Seals are widely used in various industries and are particularly useful in the oil and gas industries. They are capable of sealing pipe penetrations ranging in size from 10 mm to 3.6m in diameter.
Sizing Link Seals
Link Seals can be found in a range of sizes to fit most applications. The size of the Link Seal will depend on the size of the pipe and the type of application.
Working of Link Seals
Link Seals work by creating a pressure-tight seal between the pipe and the core hole, thus preventing any air, water, or gas from passing through. The pressure plates and bolts are used to apply pressure to the rubber links, creating a tight seal.
Installation of Link Seals
Link Seals are easy to install and require minimal tools and skills. All that is required is the correct size of Link Seal and the appropriate pressure plates and bolts. Once installed, they provide an air, water, or gas-tight seal that is permanent and reliable.
Advantages of Link Seal Systems
1. Positive Hydrostatic Sealing:
Link seals provide a positive hydrostatic seal, ensuring that no water or other liquids can pass through the pipe. This allows them to provide excellent protection against the elements and any potential damage.
2. Resistant to Temperature and Chemical Attack:
The link seal systems are designed to be resistant to extreme temperatures ranging from -500C to 2040C and chemical attack, making them ideal for protecting pipes in harsh environments.
3. Long Sealing Life:
Link seals have a long sealing life and are designed to last for years, providing reliable protection for your pipes.
4. Easy to Adjust and Re-Fit:
Link seals are easy to adjust and re-fit, making them an ideal choice for pipes that may need to be moved or modified in the future.
5. Installation During Pipe Operation:
Link seals are designed to be installed during pipe operation, meaning no plant shutdown is required for installation.
6. Fire-Rated Form:
Link seals are available in a fire-rated form, allowing them to provide optimal protection when used in a fire-prone environment.
7. Absorbs Slight Pipe Movements:
Link seals can absorb slight pipe movements, allowing them to remain tightly sealed and protect the pipes from any potential damage.
8. Economical:
Link seals are an economical choice, providing long-term protection for your pipes at an affordable price.
9. Maintenance-Free:
Once installed, link seals are almost maintenance-free and require very little upkeep.
10. Wide Range of Sizes:
Link seals are available in a wide range of sizes to suit any requirement, making them a versatile choice for any application.
11. Shock and Vibration Protection:
Link seals are designed to absorb shock, sound, and vibration, making them ideal for use in areas where these factors could potentially damage the pipes.
Applications of Link-Seal
Link seals are widely used in a variety of industries due to their many benefits. Some of the most common applications of link seals include:
Manhole Pipe Entry Seals:
Link seals can be used to create a watertight seal between manhole pipes and walls, preventing water from entering the pipe and causing damage.
Cased Road Crossings:
Link seals can be used to provide a watertight seal between cased road crossings and the surrounding ground. This prevents water from seeping into the road and damaging the structure.
Thermal Storage Systems:
Link seals are often used in thermal storage systems to create an airtight seal between the thermal storage tanks and the pipes that feed the system. This prevents any heat or cold from escaping the system, ensuring it runs efficiently.
Dual Containment Seals:
Link seals are often used to provide a watertight seal between dual containment systems. This prevents any hazardous materials from escaping the system and causing environmental damage.
Fire Protection Wall Penetrations:
Link seals can be used to create a watertight seal between fire protection walls and the pipes that penetrate them. This prevents any water from entering the wall and causing damage to the structure.
Manhole Pipe Entry Seals: Link seals are used to create a watertight seal between manhole pipes and walls, preventing water from entering the pipe and causing damage.
Cased Road Crossings: Link seals are used to provide a watertight seal between cased road crossings and the surrounding ground, preventing water from seeping into the road and damaging the structure.
Thermal Storage Systems: Link seals are used to create an airtight seal between thermal storage tanks and the pipes that feed the system, ensuring that no heat or cold escapes the system.
Dual Containment Seals: Link seals are used to provide a watertight seal between dual containment systems, preventing any hazardous materials from escaping the system.
Fire Protection Wall Penetrations: Link seals are used to create a watertight seal between fire protection walls and the pipes that penetrate them, preventing any water from entering the wall and causing damage.
Waste Treatment Plants: Link seals are used to create a watertight seal between waste treatment plants and the surrounding environment, preventing any hazardous materials from escaping the system.
Cased Railroad Crossings: Link seals are used to create a watertight seal between cased railroad crossings and the surrounding ground, preventing water from seeping into the road and damaging the structure.
Electrical Isolation of Pipes: Link seals are used to create an airtight seal between pipes and the electrical wiring that runs through them, preventing any electrical current from leaking out.
Precast Concrete Vault Seals: Link seals are used to create a watertight seal between precast concrete vaults and the surrounding ground, preventing water from seeping into the vault and causing damage.
Insulated Pipe Seals: Link seals are used to create an airtight seal between insulated pipes and the surrounding environment, preventing any heat or cold from escaping the system.
Noise Dampening: Link seals are used to create a soundproof seal between walls, floors and ceilings, preventing any noise from escaping the system.
Flexible Sign & Pole Supports: Link seals are used to create a watertight seal between flexible sign and pole supports and the surrounding ground, preventing any water from seeping into the supports and causing damage.
Marine Applications: Link seals are used to create a watertight seal between marine vessels and the surrounding environment, preventing any water from entering the vessel and causing damage.
Electrical Isolation of Pipe Supports: Link seals are used to create an airtight seal between pipe supports and the electrical wiring that runs through them, preventing any electrical current from leaking out.
Mining Industries: Link seals are used to create a watertight seal between mining operations and the surrounding environment, preventing any hazardous materials from escaping the system.
Pulp & Paper Industries: Link seals are used to create a watertight seal between pulp and paper industries and the surrounding environment, preventing any hazardous materials from escaping the system.
Decorative Fountains: Link seals are used to create a watertight seal between decorative fountains and the surrounding environment, preventing any water from escaping the system.
High-Pressure Tank Guards: Link seals are used to create a watertight seal between high-pressure tanks and the surrounding environment, preventing any water from entering the tank and causing damage.
Underground Steel Tanks: Link seals are used to create a watertight seal between underground steel tanks and the surrounding environment, preventing any water from entering the tank and causing damage.
Electrical Contractors: Link seals are used to create a watertight seal between electrical contractors and the surrounding environment, preventing any hazardous materials from escaping the system.
Valve and Flange Pits: Link seals are used to create a watertight seal between valve and flange pits and the surrounding environment, preventing any hazardous materials from escaping the system.
Pool Contractors: Link seals are used to create a watertight seal between pool contractors and the surrounding environment, preventing any water from entering the pool and causing damage.
Waste Water Treatment: Link seals are used to create a watertight seal between waste water treatment plants and the surrounding environment, preventing any hazardous materials from escaping the system.
Telecommunications: Link seals are used to create a watertight seal between telecommunications systems and the surrounding environment, preventing any hazardous materials from escaping the system.
Refrigeration Buildings: Link seals are used to create a watertight seal between refrigeration buildings and the surrounding environment, preventing any hazardous materials from escaping the system.
Guard Post Assemblies: Link seals are used to create a watertight seal between guard post assemblies and the surrounding environment, preventing any water from entering the posts and causing damage.
Power Generation Dams: Link seals are used to create a watertight seal between power generation dams and the surrounding environment, preventing any water from entering the dam and causing damage.
Offshore Oil Rigs: Link seals are used to create a watertight seal between offshore oil rigs and the surrounding environment, preventing any hazardous materials from escaping the system.
Coal Preparation Plants: Link seals are used to create a watertight seal between coal preparation plants and the surrounding environment, preventing any hazardous materials from escaping the system.
Tunneling Operations: Link seals are used to create a watertight seal between tunneling operations and the surrounding environment, preventing any hazardous materials from escaping the system.
Precast Concrete Manufacturers: Link seals are used to create a watertight seal between precast concrete manufacturers and the surrounding environment, preventing any hazardous materials from escaping the system.
Perimeter Berm Installations Around Tank Farms: Link seals are used to create a watertight seal between perimeter berm installations and the surrounding environment, preventing any hazardous materials from escaping the system.
Flow Restrictors in Sewer Maintenance: Link seals are used to create a watertight seal between flow restrictors and the surrounding environment, preventing any water from entering the sewer and causing damage.
Fluid Overflow Devices: Link seals are used to create a watertight seal between fluid overflow devices and the surrounding environment, preventing any hazardous materials from escaping the system.
Noise and Sway Dampener: Link seals are used to create a soundproof seal between walls, floors and ceilings, preventing any noise from escaping the system.
Through Deck Fire Breaks: Link seals are used to create a watertight seal between through deck fire breaks and the surrounding environment, preventing any water from entering the deck and causing damage.
Bridge Construction: Link seals are used to create a watertight seal between bridge construction and the surrounding environment, preventing any hazardous materials from escaping the system.
Septic Tank Installations: Link seals are used to create a watertight seal between septic tanks and the surrounding environment, preventing any hazardous materials from escaping the system.
How does a Link Seal Work?
Installing Link Seal
Link seals are installed by positioning the belt between a pipe and the annular wall. The belt is then tightened following a proper tightening sequence to ensure it is secure.
Radial Expansion of Link Seal
Once installed, the link seals provide a pressure-tight and secure sealing through the radial expansion of the rubbers in the annular spaces.
Sectional Drawing of Wall Penetration Sealed by Link Seal
A sectional drawing of a wall penetration sealed with Link-seal can be seen below. This illustration provides an example of how a link seal works to create a pressure-tight and secure seal.
Installation of Link-Seal System
Step 1: Centering the Pipe in Casing or Wall Opening
Before beginning the installation of the link-seal system, the pipe should be centered in the casing or wall opening. It should be adequately supported on both ends.
Step 2: Connecting the Belt Around the Pipe
The next step is to loosen the rear pressure plate of the link-seal belt with a nut. This allows the links to move freely. Both ends of the belt should then be connected around the pipe.
Step 3: Sliding the Belt Assembly into the Annular Space
The link-seal belt assembly should then be slid into the annular space. All bolt heads should be facing the installer. Extra slack or sag is normal and so links should not be removed.
Step 4: Tightening the Bolts
Using a hand socket Allen head, hand socket, or off-set wrench, the installer should start at 12 o’clock and proceed clockwise. Each bolt should only be tightened four turns at a time. This process should be repeated until all sealing elements “bulge” around all pressure plates.
Step 5: Completion of Link Seal Installation
Once all sealing elements bulge out, the link seal installation is complete and ready for use.
Sizing Link Seals – Annular Space Calculation
When sizing link seals, the first step is to calculate the annular space. This is the half the difference between the wall/sleeve opening ID and the actual pipe OD. This can be calculated using the following equation:
Annular Space=(ID of wall opening or sleeve-Actual Pipe OD)/2
Sizing Link Seals – Number of Links Calculation
The next step is to calculate the number of links required for each seal. This can be done by first calculating the bolt circle diameter. This can be done using the following formula:
Bolt Circle Diameter=(Wall/Sleeve opening ID+Pipe Actual OD)/2
Once the bolt circle diameter is calculated, the number of links per seal can be determined using the following equation:
Number of links per seal=(Bolt circle diameter X 3.14)/Arc Length
The arc length or chord length will be available in the manufacturer catalogs.
Sizing Link Seals – Final Step
Once the annular space and number of links per seal have been calculated, the required link-seal can easily be selected from the manufacturer’s catalog. This completes the sizing process for link seals.
Link Seal Sizing Chart
Figure below provides an example of a typical link seal size chart. When determining the appropriate link seal size, it is important to refer to the manufacturer’s catalog for accurate selection.