Experience Counts!   LineBacker® 251™ Sealing Gaskets Description Typical Application Benefits/Features Specifications Warranty Installation How to Order Typical Specification Resources Related Products Description LineBacker® sealing gaskets utilize a patented rectangular sealing element, referred to as a “quad” ring, in combination with a unique groove design to effectively seal and isolate flanges of all types. With the unique “quad” ring design, elastic memory is provided for elastomers not normally associated with this characteristic. Materials such as AFLAS, TFE (Teflon) and KALREZ may therefore be used as sealing elements which dramatically increases the options available for matching gasket materials to service and environmental conditions. This greater variety of materials also provides excellent temperature and chemical range compatibility. LineBacker® sealing gaskets are self energizing with theoretical near zero “m” and “y” factors resulting in effecting a positive seal without excessive bolt loads required with flat gaskets. Significant chemical and material composition improvements have provided an opportunity for the development of three gaskets, designed to address the regulations associated with asbestos substitute gaskets and fugitive emissions. LineBacker® 250 gaskets are manufactured from new proprietary materials that provide excellent resistance against environmental leakage without the health hazards associated with asbestos type gaskets. Before Tightening The flange faces come into contact with the sealing elements, which extend slightly above the surface of the retainer. As the flange is tightened the sealing elements are compressed and move sideways into the inclined portion of the groove, developing a high unit pressure against the flange faces. After Tightening The flange faces have come into firm contact with the retainer, thus encapsulating the sealing elements within grooves. At the same time, the unique LineBacker seal configuration provides elastic memory for elastomers not normally associated with this characteristic - resulting in a simple flat gasket with extremely high loading and self energizing characteristics without adverse cold flow problems. TYPE E GASKET The gasket retainer extends out to the O.D. of the flange. Holes are cut in a type "E" gasket at the bolt circle to accommodate threaded studs or bolts. TYPE F GASKET The gasket retainer extends out to the I.D. of the bolt circle. Benefits/Features Eliminates Flange Leaks. Guards against blowouts. Protects against fire and hostile environments. Resolves asbestos subsitiution concerns. Eliminates cold flow problems. Reduces Inventory Costs. Increases the overall life of the system. Sizes All standard ANSI and API flange sizes from 1/2" and above. Custom odd sizes and shapes. Pressure Ratings All ANSI and API rated flanges. Pressures from hard vacuum to 50,000 psi and higher. Proprietary Gasket Material Specifications TEST DESCRIPTION RESULT ASTM D-149 Dielectric Strength Volts/mil (Short Time) 550 ASTM D695 Compressive Strength 50,000 psi ASTM D229 Water Absorbtion 0.15% ASTM D790 Flexural Strength 50,000 psi ASTM D785 Hardness 110 ASTM D256 IZOD Impact Strength 12.5 ft-lbs/in ASTM D638 Tensile Strength 45,000 psi ASTM D32 Shear Strength 20,000 psi ASTM F-36 Compressibility 2.1% ASTM F-36 Recovery 88.9% ASTM F-38(B) Creep Relaxation 5.1% DIN-3535 Gas Permeability 0.43 cm3/min. DIN 52913 Stress Relaxation N/A -- Operating Temperature Cryogenic to +250º F. Cryogenic to +121º C. Suggested Sealing Gasket Material Compatibility Charts Warranty All products are warranted against failure caused by manufacturing defects for a period of one year. Any product found to be so defective and returned within one year from date of shipment will be replaced without charge. The above warranty is made in lieu of, and we disclaim, any and all other warranties, expressed or implied, including the warranties of merchantability and fitness for a particular purpose, and buyer agrees to accept the products without any such warranties. We hereby disclaim any obligation or liability for consequential damages, labor costs or any other claims or liabilities of any kind whatsoever. Installation Open packaging to inspect and determine that components are as specified. Check the gasket I.D. It should be no greater than the flange I.D. Flanges shall be free of pits, gouges, rust, debris, oil and grease. Surface finish shall be no greater than 250 RMS. Refinish flange faces if corrective measures do not meet the foregoing. Check flange and bolt hole spot facings for burrs, etc… and clear from facings. Check bolts and nuts and clean. Apply non-conductive lubricant to all threads and flange side of nuts. Align flanges so they are concentric and parallel and install gasket carefully. USE NO LUBRICANT, GREASE OR ADHESIVES ON EITHER THE GASKET OR FLANGE FACES, Guard against damaging sealing element. Line up bolt holes with non-tapered drift pins using three at 120° degrees separation (particularly large flanges), or at least two at 180° degrees separation. Insert studs, nuts and washers, placing lubricated face of nut next to steel washer (this will help to reduce galling of the insulating washer on flange, should the whole bolt assembly rotate). Galling: If serious galling of insulating washers persists, replace with high strength washers. (minimum 50K psi or greater). Initially cross-tighten bolts until flange to gasket contact has been made. Check for a flange segment that may show a gap or separation between gasket and flanges, using flashlight, calipers, or feeler gauge. If one exists, the flanges are not parallel. Directly 180° degrees opposite widest part of indicated gap, loosen nuts, even if only finger tight, one or more turns. Return to segment with gap and tighten until both flanges are in contact with gasket retainer. This procedure is necessary to prevent restriction of flange rotation over the fulcrum formed by the outer edge of the two raised faces at points in contact with gasket retainer. The restriction will cause exceptionally high flange to gasket clamp loading at this point, with possible damage to gasket retainer, PLUS diverting necessary clamp loading bolt torque energy to correcting alignment on the opposite segment. Re-tighten loosened nuts and proceed with torqueing of the bolts according to PSI diagram, to 10-15% of specified torque. Remove drift pins and replace with bolts, nuts and washers, tightened to the same values as others in place. Repeat torque sequence, increasing to 50% of balance. Repeat tightening to final torque. Optional – it is always a good policy to go completely around flange checking bolt to bolt for proper torque, particularly on large diameter piping systems. All the above should be done with torque wrenches (mechanical and hydraulic) or with a stud tension measuring device. Always wear appropriate safety equipment! Important: Check gasket for flange type on which to be used (ie). Slip or weld-neck etc…If in doubt do not install, consult supplier or PSI. To provide even sealing pressure on a flange gasket it is recommended that the bolts be “snugged” up in the sequence shown on chart until the flange faces are in contact with the gasket. After the flange faces are in contact with the gasket firmly tighten the bolts in the same sequence. Note: Although this diagram shows 24 bolts, the same basic procedure should be used with flanges having more or less bolts. When installing gaskets made of compressible dielectric material and tightened cold; “hot flow” of the gasket material may occur under operating conditions, resulting in loss of bolt pressure. It is advisable therefore, to re-tighten bolts after operating temperature has been reached – preferably at zero line pressure and ambient temperature. Under no circumstances should the system be allowed to return to operating temperature after the initial cycling to ambient temperature without checking and re-tightening bolts where needed. Suggested torque values for PSI sealing gaskets. How To Order To order LineBacker® Sealing/Isolating Gaskets please indicate the following: Quantity Nominal Pipe Size Pressure Rating Gasket Type: E or F Gasket Style: LineBacker® Retainer Material Sealing Element Weld neck or slip-on application Note all special requirements. Contact your local distributor or Pipeline Seal & Insulator, Inc. Distributor Locator Contact PSI Typical Specification Resources Sealing Gaskets A concise 8 page booklet that includes all PSI Sealing Gaskets including specifications, material compatibility charts and installation instructions. PDF File Size = 1,014KB. Flange Isolation Kits. An 8 page booklet that includes discriptions of all PSI flange isolation kits with gasket, sleeve and washer physical properties and material compatibility charts. PDF File Size = 532KB. Related Products Isolating Fittings