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Unformatted text preview: Insulating Sets
Insulating sets comprise of a phenolic laminate or neoprene faced phenolic laminate gasket (Style NCA and NCB only) which is located between the flange sealing faces, phenolic laminate bolt sleeves, two insulating washers per bolt for maximum protection and two plated mild steel washers per bolt. Stainless steel washers can be supplied upon request. Insulating sets are essentially used for pipeline flange corrosion protection, where a seal is required between dissimilar flange materials. The use of dissimilar metallic flanges with a conductive gasket material accompanied with a suitable electrolyte may set up a galvanic cell which will corrode the anodic metal. Insulating sets are also used to electrically isolate flange joints, preventing the flow of electrostatic charge along pipelines. There are three standard styles of insulating sets available to suit raised face, flat face, and ring grooved flanges, as illustrated below.
One 3mm (1/8") thick plated steel washer for each nut. One Insulating washer for each nut One full length insulating sleeve for each bolt 3mm (1/8") thick insulating gasket or oval ring for ring joint flanges One insulating washer for each nut One 3mm (1/8") thick plated steel washer for each nut Standard Styles
It is also recommended that for complete electrical insulation protection that selfStyle NCA adhesive tape is wrapped around the outside diameter of the flange to prevent the Full Face Gasket ingress of foreign matter. Insulating Set Assembly With style NCA and NCB insulatSuitable for flat face and raised face flanges. This style miniing sets it is imperative that the bore of mizes the ingress of conductive foreign matter between the the gasket is equal to that of the pipe. portion of the flanges outThis will prevent any foreign matter side the raised faces and from accumulating in the annular space reduces the risk of bridging. between the bore of the gasket and the bore of the pipe thus preventing bridging. Phenolic laminate provides excellent insulating properties as well as corrosion resistance. See table for typical properties of 3mm (1/8") thick phenolic. Other gasket styles such as Sigma and non-asbestos sheets may also be suitable. 1/8" thick steel washer 1/8" thick insulating washer Insulating sleeve 1/8" thick insulating gasket 1/8" thick insulating washer 1/8" thick steel washer Style NCB
Inside Bolt Location Gasket Insulating Set Assembly
Utilizes a central gasket which locates within the bolts. Typical Properties of Phenolic Gaskets Maximum axial compressive stress Axial electric strength in oil @ 90C (190F) Maximum operating temperature Minimum operating temperature 315MPa (45,700 psi) 23kV/cm (58kV/in) 120C (250F) -60C (-76F) Style NCC
Ring Joint Gasket Insulating Set Assembly
Insulating oval section ring joint will fit into a standard RTJ flange ring groove. As standard, Flexitallic insulating kits are dimensioned to suit schedule 80 pipe suitable for use on standard and non-standard flange assemblies up to and inclusive of Class 2500. TYPICAL APPLICATIONS
Offshore installations, sea water environments, hydrocarbon service, chemical installations, oil refining pipelines requiring galvanic corrosion protection and electrical insulation. ...
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