VIP TUNNEL SEGMENT GASKETS www.vip-polymers.com
GLOBALLY APPROVED SEALING GASKETS VIP-Polymers was founded in 1923, specialising in seals and gaskets for high pressure potable water applications. The company has since developed its specialist knowledge and expertise, to become recognised as one of the world s leading manufacturers of gaskets for use in potable and drainage water applications. Our extensive manufacturing capability has quality systems approved by BSi to ISO 9001, and includes our own laboratories where we design and develop rubber formulations. The mixing facilities and moulding and extrusion equipment converts the compound into the final rubber product. In addition to its range of internationally approved rubber compounds, VIP is a global supplier with manufacturing operations in Wuxi in China, Ras Al Khaimah in the UAE, and its head office in Cambridgeshire, UK. 2 www.vip-polymers.com
ELASTOMERIC TUNNEL SEGMENT GASKETS (TSGS) Elastomeric (rubber) gaskets make up one of the most effective systems for segmentally lined tunnels where sealing is required against water ingress, or for retention in tunnels used for fluid transport or storage. The gaskets are manufactured from high-grade rubber compounds, which meet many internationally recognised standards including EN681-1; the material requirements standard for pipe and joint seals used in water and drainage applications. The complex section of the gaskets is designed to provide the energy within the seal, generating the sealing function once the segments have been assembled, whilst minimising closure forces. VIP offers a range of gaskets to suit various applications and specifications. In addition, its team of technical engineers have the experience and detailed knowledge to design bespoke gaskets for unique conditions. Their experts also prove the gasket in its dedicated test facility, which replicates the segment assembly, build conditions and sealing pressures. www.vip-polymers.com 3
TECHNICAL DATA The TSGs are manufactured in VIP s plant in Cambridgeshire in the UK, which is approved by The British Standards Institute to ISO 9001. RUBBER COMPOUND The rubber is compounded at our on-site mixing facility to proven formulations developed by VIP s rubber technologists, and meets WRAS and other internationally recognised standards where required. EXTRUSION The gasket section is extruded through one of the most modern microwave curing lines, then cut and joined to suit the segment requirements. CORNER JOINTS The corner joints are manufactured in obtuse, acute and 90 angles to fit with the corresponding segments. Their design ensures that the sealing properties and closure forces match the extruded gasket section. LIFE EXPECTANCY TSGs are generally manufactured from EPDM, which is a synthetic grade of rubber but can be manufactured in other grades of rubber if required. A study carried out by Loughborough University in the UK on behalf of VIP concludes that one of the major elements affecting the gaskets longterm sealing ability is Stress-Relaxation. 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. Residual Sealing Force % 120 100 80 60 40 20 EPDM LONG-TERM STRESS RELAXATION x x x x x x x x x x 100 years 120 years 150 years 0 0 1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Log time (hr) Water at 23 o C Extracted from Stress Relaxation in Compression by Professor A.W.Birley, Loughborough University of Technology x 4 www.vip-polymers.com
VIP-POLYMERS: STANDARD GASKETS A typical selection of gaskets which can be either glued into the segment groove or in some instances, cast-in to the segment. VIP024 VIP028 VIP028CI VIP028LHT VIP035 VIP035CI TESTING Gaskets are tested in specially designed test rigs, which replicate the build of a segment ring. T & X rig testing is carried out at our in house testing facility in Huntingdon as required. Tests are undertaken at maximum and minimum gaps, and zero-to-maximum offset/ deflection. SEALING PRESSURE V GAP Groove Bottom Distance (mm) A 36 34 32 30 28 26 24 22 30 LOAD DEFLECTION CURVE Groove Bottom Distance (mm) A 36 34 32 30 28 26 24 22 40 Water Pressure (Bar) 25 20 15 10 5 Load (kn/m) 35 30 25 20 15 10 5 0 14 12 10 Offset (0mm) Offset (5mm) Offset (10mm) 8 6 4 2 0 Gap (mm) B Diagram showing typical pressure curve 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Deflection (mm) B Diagram showing typical load deflection curve www.vip-polymers.com 5
HYDROPHILIC GASKETS VIP also manufactures a hydrophilic gasket, which swells when in contact with water and does so in three main formats: 1 Simple Hydrophilic Strip 2 Hydrophilic Cord Inserted into a slot in a TSG prior to installation 3 Hydrophilic Strip Integrally Bonded onto an Elastomeric TSG NEW! Our patent (pending) corner jointing system for cast in TSGs is designed specifically to eliminate corner point loading often the cause of cracked and damaged segments. No solid corners Latest laser guided cutting technology enables virtually any joint angle to be achieved. Today, our extensive range of glued in place, hydrophilic and cast-in gaskets are selected as original equipment by many of the leading Global concrete segment manufacturers. 6 www.vip-polymers.com
ACCESSORIES & SERVICE ADHESIVE VIP can recommend a number of approved adhesive suppliers for the application of the gasket on to the segment. If required, we can also arrange the supply of the adhesive. LUBRICANTS VIP recommends applying lubricant to the surface of the gasket to assist the segments sliding into place. 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 (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. www.vip-polymers.com 7
VIP-Polymers Ltd 15 Windover Road, Huntingdon, Cambridgeshire, PE29 7EB, United Kingdom +44 (0)1480 411333 sales@vip-polymers.com www.vip-polymers.com