CAST-IN TUNNEL SEGMENT GASKETS

Cast-in gaskets (also known as anchored gaskets or cast in situ gaskets) are integrated with the segment during the casting process.

This is opposed to being glued into a pre-made groove once the concrete segments have been cast.

Cast-in seals ‘anchor’ themselves to the segment as the concrete surrounds the legs at the base of the seal.

This process ensures a consistent positioning of the gasket around the segment.

The design of the legs ensures that the seal is secure in the segment and will not move during or after the segment is cast.

This is especially important during installation of the tunnel segments.

Benefits of Cast-in Gaskets

- No need to apply adhesive
- Cleaner to work with
- Provide cost savings due to the removal of adhesive and the gluing process.
- A more secure fit in the segment leading to reduced movement of the seal during installation and increased performance

UNIQUE CORNER JOINTING SYSTEM

No Solid Corners

Cracked or damaged segments caused by corner point loading has traditionally been a problem faced by tunnelling engineers and designers.

VIP’s Cast-in gaskets are designed specifically to eliminate this due to the unique patented (GB2541978 – international patent pending) corner jointing system.

This has allowed us to dramatically reduce the volume of rubber at the corners, thus ensuring the gasket can collapse into the groove and the load on the corners is equal to the rest of the gasket.

MINIMISING RUBBER VOLUME AT THE CORNER JOINT

VIP’s unique jointing process results in the profile of the gasket being maintained up to the corner edge. This ensures that the compression performance of the gasket is equal along the entire face of the gasket.

This differs to a traditional shot-joint corner which can result in excess rubber travelling along the gasket voids during the moulding process.

This results in making the gasket unable to compress at the corners due to the voids being full of rubber, creating a ‘solid’ corner.

The energy exerted at these points during closure of the segments can lead to cracks and spalling as it dissipates through the segment, finding the path of least resistance.

CORNER ANGLES THAT PERFECTLY MATCH THE SEGMENT

VIP can manufacture corners for cast-in gaskets to obtuse, acute and 90° angles, therefore matching the profile of the segment design perfectly.

90° Angles
90° Angle

Acute Angles
Acute Angles

Obtuse Angles
Obtuse Angles

Z Axis Angles

Segment design can differ with each project. Recognising this and the importance of the gasket matching the exact shape of the segment.

VIP can also vary the profile orientation along the Z axis.

The following profiles comprise VIP’s cast-in core range.

Further profiles are available or can be developed on request to meet specific design requirements.

GLUED-IN TUNNEL SEGMENT GASKETS

Traditionally the industry has used elastomeric gaskets that are glued into pre-formed grooves in the concrete segments.

VIP manufactures a range of profiles which are compatible with many pre-existing segment mould groove designs.

The following profiles comprise VIP’s glued-in core range. Further profiles are available or can be developed on request to meet specific design requirements.

Glued-in VIP028LHT Tunnel Segment Gasket

CORNER ANGLES THAT PERFECTLY MATCH THE SEGMENT

VIP’s glued-in profiles have corner joints that can be manufactured to match the angles of the segment design including 90°, acute and obtuse angles.

The corners are formed using an injection process in moulds that match the profile of the extruded gasket.

This ensures that when the segments are joined together, the gasket can collapse into the groove and the load on the corners is equal to the rest of the gasket.

HYDROPHILIC TUNNEL SEGMENT GASKETS

VIP also manufacture hydrophilic gaskets for both our Cast-In and Glued-In profiles.

Hydrophilic compounds are designed to swell when they come into contact with water which can close the gap between the gasket faces.

VIP Hydrophilic Gasket Types

VIP supply hydrophilic gaskets in 2 main formats:

Hydrophilic cord inserted into a slot in a TSG prior to installation Hydrophilic Chord

Hydrophilic strip co-extruded onto an elastomeric TSG Co-extruded Hydrophilic Strip

TSG RUBBER COMPOUNDING AND MANUFACTURE

VIP’s tunnel segment gaskets are manufactured in our Cambridgeshire headquarters in the UK, which is certified by The British Standards Institute to ISO 9001, using the latest manufacturing equipment and processes.

RUBBER COMPOUND

VIP compounds its own rubber at our on-site mixing facility to proven formulations developed by VIP’s rubber technologists. The compounds used meet WRAS and other internationally recognised standards where required.

Predominantly EPDM is the rubber of choice for tunnel segment gaskets as it provides the sealing and material qualities required. However in instances where resistance to more aggressive chemicals is required, VIP can compound and manufacture using NBR (Nitrile).

LIFE EXPECTANCY

A study carried out by Loughborough University in the UK on behalf of VIP concludes that one of the major elements affecting the gaskets’ long term sealing ability is ‘Stress-Relaxation’. This is the measurement of the force that a compressed gasket exerts over time which is crucial to the sealing performance.

The research also revealed that with correctly formulated and processed rubber, as supplied by VIP, the life expectancy of our gaskets is in excess of 120 years.

EXTRUSION

To begin the manufacturing process, VIP’s gasket profiles are extruded through one of the most modern microwave curing lines. This manufacturing technique creates the profile length by forcing the rubber through a die prior to curing. This is then cut to lengths determined by the segment requirements.

CORNER JOINTS

All VIP’s corner joints can be manufactured in obtuse, acute and 90° angles to perfectly fit with the corresponding segments.

Using the latest laser guided cutting technology enables virtually any joint angle to be achieved and their design ensures that the sealing properties and closure forces match the extruded gasket section.

QUALITY INSPECTIONS

In order to ensure the final product meets the high standards set by VIP, physical checks are made by our quality team both during the manufacture process and on final completed gaskets against:

Profile Size – to ensure a consistent profile shape during the extrusion process
Joint Integrity – to check the strength of moulded joints
Geometric Requirements – to check the shape of the finished gasket meets the segment design requirements

IN-HOUSE LABORATORY AND TSG TESTING

VIP’s laboratory and quality team undertake various tests and inspections throughout the manufacturing process of our TSGs.

These tests provide assurance that our products are produced to the highest standard and perform as expected.

Tests are undertaken on both the uncured rubber compound prior to manufacture with further tests on the final extruded product which check for:

Rheometry
Hardness
Tensile strength
Elongation
Compression set
Dimensional checks
Stress relaxation

Completed gaskets are finally checked on specially designed jigs to ensure they are the correct dimensions for the corresponding segment shape.

Tests Designed to Replicate Real World Applications

Gaskets are also tested at our UK headquarters in specially designed test rigs, which replicate the build of a segment ring in order to measure their performance.

VIP undertake a range of tests using T & X rig testing in order to replicate closure forces and pressures experienced both during the tunnel build and throughout the service life of a tunnel.

Pressure testing is undertaken at maximum and minimum gaps, and zero-to-maximum offset / deflection.

This replicates the gaps and displacements that occur between segments either as a result of building tolerances, changes in direction of the tunnel or due to the effects of ground movement.

Pressure test With No Offset

Pressure test With Offset

Typical Pressure Curve

Diagram showing typical pressure curve

Typical Load Deflection Curve

Diagram showing typical load deflection curve

ACCESSORIES AND SERVICE

ADHESIVE

VIP can recommend a number of approved adhesive suppliers for the application of glued-in gaskets onto the segment. If required, we can also arrange the supply of the adhesive.

LUBRICANTS

VIP recommends applying lubricant to the surface of the gasket during segment installation to assist the segments sliding into place.

This process reduces the friction between gaskets, ensuring corner positioning and reducing the risk of gaskets moving or pinching during installation which can potentially affect their performance. We can recommend and supply an appropriate WRC-approved lubricant.

STORAGE

TSGs should be stored in the same conditions as for most elastomeric products and ideally in accordance with ISO 2230:2002 (rubber products guidelines for storage). VIP can supply details upon request.

QUALITY

VIP operates a quality system, which is approved to ISO 9001 standard and certified by BSi. We are renowned in the seal and gasket industry for the high quality of all of our products, and our approach to quality extends to TSGs.

VIP launch new tunnel segment gasket brochure

Posted on 21st March 2016 by VIPPolymers

Hot off the press!

Available to download, VIP have created a new product brochure specifically for the tunnel segment gasket product group. The brochure includes details of our gasket corner jointing system which eliminates corner point loading during installation – often the cause of cracked and damaged concrete segments.

Download the brochure here: Tunnel Segment Gasket Brochure

PIPE REPAIR CLAMPS & FITTINGS

VIP-Polymers have for a number of years developed and manufactured a range of sealing gaskets for pipe fittings and repair clamps used on a variety of applications:

End load restraint systems
Repair couplings
Repair clamps
(using “waffle pattern” repair mats)
Stepped couplings
Flange adaptors
Dismantling joints
Shoulder couplings
Gripper couplings

With an advanced rubber to metal bonding facility available in-house, we can also offer reinforced repair mats incorporating components made from stainless steel, lead, aluminium, copper and iron. Large compression and injection moulding presses enable us to offer components up to 2.4 metres wide whilst our extrusion facility enables us to produce profiles of up to 300mm width.

Approvals

Many of the compounds we use to manufacture repair clamp gaskets hold multi region potable water approvals. This means our customers enjoy the benefits of reduced inventory as stocks of gaskets for different global regions are no longer necessary.

STANDARDS

BS6920. Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water.

ISO 3302-1:2014. Specifies classes of dimensional tolerances and their values for moulded, extruded, and calendared solid rubber products.

BS EN 681-1. Elastomeric seals. Material requirements for pipe joint seals in water and drainage applications.

ISO 2230:2002. Rubber products. Guidelines for storage.

BS EN 598:2007+A1:2009. Ductile iron pipes, fittings, accessories and their joints for sewerage applications. Requirements and test methods.

BS EN 545:2010. Ductile iron pipes, fittings, accessories and their joints for water pipelines. Requirements and test methods.

TYTON® GASKETS

Tyton® Seals

Dual Hardness and available for ductile iron pipes up to 2200mm diameter
Physical properties in accordance with EN681-1 WA/WC
Designed to fit DIN28603 sockets and suitable for pipe manufactured in accordance with DN545 & EN598
Materials fully WRAS approved and BS6920 compliant – up to 60º
Approved for use in Germany, France, Middle East, as well as a number of other countries globally

VIP-Polymers – The world’s largest manufacturer of Tyton® Gaskets

VIP-Polymers can mould dual hardness Tyton® gaskets for Ductile Iron pipe in sizes from DN80 to DN2200. With over 40 years’ experience of manufacturing these seals, today our Tyton® gaskets are selected by a number of the leading Ductile Iron Pipe manufacturers worldwide as original equipment.

The Tyton® joint is a standard push-fit, flexible joint for water pipelines offering a high performance joint with a number of benefits;

Quick and easy to install.
Capable of angular deflection without loss of performance

Table of Maximum Working Pressures

Nominal Diameter mm	Angular Deflection	Maximum Working Pressure
DN80	5°	60 bar
DN100	5°	60 bar
DN150	5°	60 bar
DN200	5°	60 bar
DN250	5°	53 bar
DN300	5°	47 bar
DN350	4°	43 bar
DN400	4°	40 bar
DN450	4°	38 bar
DN500	4°	36 bar
DN600	4°	33 bar
DN700	4°	31 bar
DN800	4°	29 bar
DN900	4°	28 bar
DN1000	4°	27 bar
DN1100	4°	26 bar
DN1200	4°	25 bar
DN1400	4°	25 bar
DN1800	4°	25 bar
DN2000	3°	20 bar
DN2200*	3°	20 bar

n.b. Maximum angle of deflection can vary depending on the pipe manufacturer.

VIP-Polymers offer dual hardness Tyton® gaskets in both EPDM to BS EN681-1 WA/WC for and in Nitrile material meeting the physical requirements of BS EN682. In addition to physical properties, our Tyton® gaskets are approved for use by potable water authorities across the globe. Details of these approvals can be supplied upon request.

Please note when ordering that above DN600, not all Tyton® socket dimensions are in accordance with DIN 28603 so please consult our technical department to ensure the correct gasket is selected.

STANDARDS

BS6920. Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water.

ISO 3302-1:2014. Specifies classes of dimensional tolerances and their values for moulded, extruded, and calendared solid rubber products.

BS EN 681-1. Elastomeric seals. Material requirements for pipe joint seals in water and drainage applications.

ISO 2230:2002. Rubber products. Guidelines for storage.

BS EN 598:2007+A1:2009. Ductile iron pipes, fittings, accessories and their joints for sewerage applications. Requirements and test methods.

BS EN 545:2010. Ductile iron pipes, fittings, accessories and their joints for water pipelines. Requirements and test methods.

VIP-WECO TRENCHLESS REPAIR SEAL

Fully installed in as little as 40 minutes!

Since the 1960s VIP-Weco internal pipe seals have been used worldwide for trenchless rehabilitation of pipes and sewers for industrial water, drinking water, waste water, fuel and gas.

VIP-Weco use WRAS approved material, comply fully with BS6920 and have a typical life expectancy of 50+ years

During the installation process, rubber sleeves made of EPDM or NBR compounds are applied over the damaged area of the inner wall of the pipe. The rubber sleeve is then held in place by stainless steel retaining bands allowing up to 20 bar of internal or up to 2.0 bar of external pressure.

Following installation of clamping bands in the corresponding grooves of the sleeves, a safe, durable and low-cost mechanical sealing solution is achieved. Typical installation time of circa 40 minutes per seal.

For special applications, we develop customised sealing solutions on request.

In addition to the VIP-Weco seals, our services include:

Pipeline repair & rehabilitation consultancy services
Installation and testing of VIP-Weco seals where required
Training and accreditation for third party installation of the VIP-Weco sealing system

Configurations

VIP-Weco Configuration 1

1). Comprises two stainless steel retaining bands and a vulcanised rubber sleeve. Suitable for sealing in-filtration leaks of up to 0.4 bar and will also seal ex-filtration leaks of up to 20bar depending upon the host pipe material and available in widths of 280mm or 480mm.

This configuration is suitable for the following pipe profiles:

Circular
Egg Shaped
Ellipse

Operating temperatures are -10 to +80 degrees Celsius (other materials offering a wider range capability available upon request).

VIP-Weco Configuration 2

2). Comprises three stainless steel retaining bands and a vulcanised rubber sleeve and a stainless steel retaining sheet. Suitable for sealing in-filtration leaks of up to 0.8 bar and will also seal ex-filtration leaks of up to 20bar depending upon the host pipe material and available in widths of 280mm or 480mm.

This configuration is suitable for the following pipe profiles:

Circular
Egg Shaped
Ellipse

Operating temperatures are -10 to +80 degrees Celsius (other materials offering a wider range capability available upon request).

VIP-Weco Configuration 3

3). Comprises four stainless steel retaining bands and a vulcanised rubber sleeve and a stainless steel retaining sheet. Suitable for sealing in-filtration leaks of up to 2.0 bar and will also seal ex-filtration leaks of up to 20bar depending upon the host pipe material and available in widths of 280mm or 480mm.

VIP-Weco END LINER SEAL

4). For end liner sealing applications; Comprises two stainless steel retaining bands and a vulcanised rubber sleeve. Suitable for sealing in-filtration leaks of up to 0.4 bar and will also seal ex-filtration leaks of up to 20bar depending upon the host pipe material and available in widths of 280mm or 480mm. Smallest diameter is DN220. This is the best solution for permanently sealing the end of Cured In Place Pipe linings (CIPP).

This configuration is suitable for the following pipe profiles:

Circular
Egg Shaped
Ellipse

Operating temperatures are -10 to +80 degrees Celsius (other materials offering a wider range capability available upon request). The VIP-Weco End Liner Seal is compatible with all other configurations of VIP-Weco Seal.

No dig pipe repair seal alleviating the need for costly pipe excavation and associated disruption

No adhesives or chemicals required
Can be used in “ovalised” pipes
Fully approved for use in UK potable water pipelines
Can be used to seal relined pipes
Available in various grades of rubber/ stainless steel to suit more aggressive environments.
Available from DN185 to DN3500+