Iron • PVC • Concrete • Clay • Rail Pads • TSG's • Extruded • Flange • Viploc VIP-Heinke has unrivalled expertise in seal design and elastomer technology, and is one of the leading manufacturers of elastomeric gaskets for the segmental lining of tunnels, commonly known as Tunnel Segment Gaskets (TSGs). Tunnel Segment Gaskets: TSGs are located in precast grooves encircling the mating faces of each segment to give a secure rubber-to-rubber waterproof seal as soon as the segments are bolted together. The low compression set and stress relaxation values of the elastomeric compound used in their manufacture enable elastomeric TSGs to recover under reduced applied load thereby maintaining a positive seal between segments despite ground movements. VIP-Heinke manufactures a range of TSGs designed for pre-cast concrete, steel and cast iron segments used in the lining of tunnels or shafts and large mains sewers. All are precision engineered to meet the precise requirements of individual projects. Benefits of Elastomeric TSGs:   Elastomeric TSGs provide an economic and effective solution for sealing tunnels and shafts against water ingress. Compared to other sealing methods, elastomeric TSGs offer many benefits. Ease of installation Effective seals when bolts are tightened, immediately creating dry joints Assurance of an effective seal despite ground movement and alternating wet and dry conditions Proven reliability, eliminating the need for costly remedial work to seal leaks after construction Proven record of durability, being resistant to chemical attack and microbiological degradation Manufacturing Capability: TSGs have complex cross-sections of ribs and holes to provide strength and compressibility. The TSGs are manufactured by an extrusion process and then cut to required lengths and finally shot-moulded for joint integrity to form a one-piece, four-sided gasket to fit into the specified groove of the segment. Technical Data: When specifying TSGs for segmented tunnel applications, there are many important factors to determine the correct gasket design to ensure an efficient, watertight seal over the projected service life of the tunnel. VIP-Heinke's engineering can provide expert assistance to determine these factors to specify the most suitable and economical TSG for a particular application. VIP-Heinke can also identify, test and demonstrate appropriate gaskets Working and Test Pressures: Segmental linings require gaskets to ensure a water-tight seal. Ground water is normally under pressure and the chosen gasket must therefore be tested for its ability to withstand the pressures involved. Ground Conditions: Ground conditions are analysed to specify that the correct elastomeric material for the gasket is selected to resist any deleterious attack. VIP-Heinke gaskets are made to simulate the worst conditions expected during the construction and service life of the tunnel. During pre testing, hydrostatic pressure is increased in a test rig to the required test pressure and maintained for a prolonged period of time, generally 72 hours. Gaps and Displacements: Gaps and displacements occur between segments, either as an allowance for building tolerances or to help steerage, line and level during the construction of all tunnels. The purpose of a TSG is to seal to the required pressure at the maximum expected gap and displacement. As the size of the gap and/or displacement increases, the ability for a given TSG to withstand water pressure decreases and there is therefore a maximum pressure at which any TSG will seal for a given maximum gap and displacement. Suitability of all selected gaskets are verified at VIP-Heinke using a special tunnel gaskets test rig. Diagram A [above] Cross section diagram through segment shows typical gap and displacement Closure Force: VIP-Heinke determines compression closing forces required to bring two segments completely together by using its testing facilities to plot forces against closure for a given gasket, expressed as kN per metre. Groove Dimensions: Groove dimensions are engineered to locate the gasket in the segment so that when the segments are closed, (ie no gap), that the volume of rubber is completely housed within the groove. If the volume of rubber exceeds the groove dimensions, it is not possible to fully close the segments. Fitting Segments & Corner Joints: VIP-Heinke's TSGs are manufactured to fit the grooves of each segment, whatever its size or shape. Fitting is a simple matter of applying the recommended amount of adhesive to the groove, stretching the TSG over the segment and fitting it into place in the groove. The adhesive ensures that the TSG is not pulled or jarred out of the groove before, or during, tunnel construction.. Corner joints are specifically designed with the necessary flexibility to accommodate corners around segments, from acute through to obtuse angles. In addition to standard quality control procedures, corner joints undergo "full opening" and "full closure" tests to ensure the integrity of each joint. Adhesives & Lubricants: VIP-Heinke recommends and supplies adhesives appropriate for bonding its TSGs to concrete or cast iron segments. Data sheets relating to the adhesive are available and VIP-Heinke can give further advice on storage and application. VIP-Heinke recommends the application of a light coating of lubricant to the surface of the TSG to help the segments slide into place.