Spiral Wound gaskets are available in a variety of styles to suit the particular flange facing being utilized on the flanges.
A winding only gasket, which is normally used on tongue and groove joints, male and female facings and groove to flat flange facings, pressures from 150 to 2500 psi. A winding is made of alternative plies of a metal strip and a soft non-metallic filler.
Style WR gaskets consist of a winding with a solid metal outer guide ring. These gaskets can be used on plain flat face flanges and on raised face flanges, gaskets made to ASME B16.20 to suit ASME B16.50 and ASME B16.47 flanges. The outer guide ring serves to center the gasket properly in the flange joint, acts as an anti-blowout device, provides radial support for the Spiral Wound components, and acts as a compression gauge to prevent the Spiral Wound component from being crushed. Normally the outer guide rings are furnished in mild steel, but can be supplied in other metal when required by operating conditions.
Style WRI is identical to style WR, with the addition of a inner ring. The inner ring also serves several functions. Primarily, it provides radial support for the gasket on the I.D. to help prevent the occurrence of buckling or imploding. Its I.D. is normally sized slightly larger than the I.D. of the flange bore, minimizing turbulence in process flow. The inner rings are normally supplied in the same material as the spiral wound component.
The WR-LS & WRI-LS gasket offers the same high integrity seal associated with the spiral wound gasket (Style WR and WRI) however, the WR-LS & WRI-LS has been designed in such a way that compression and sealing requirements are achieved under very low seating stresses. The traditional spiral wound gasket has its steel windings protruding above the compression stop, this requires a significant loading stress to compress the gasket to its optimum operating thickness. The WR-LS & WRI-LS gaskets have only soft Flexible Graphite or PTFE filler protruding above metal windings and guide ring. The filler is readily compressed thus producing the sealing mechanism at an earlier stage.
Style H gaskets are for use on boiler handhold and tubecap assemblies. They are available in round, square, rectangular, diamond, obround, oval and pear shapes with standard thickness of 4.5 mm (.175″). Style MW & MWC are available in round, obround, and oval shapes and are used for standard manhole cover plates. The standard thickness of 4.5 mm (.175″) is recommended for use in assemblies where the seat is relatively broad and bolting load is low. Inner rings of windings 3.2 mm thick with no filler, it is also available in solid steel.
The spiral wound components of Style D are identical to those of Style W and in addition have a wire loop welded to the outer periphery of the gasket, sized so as to fit over diametrically apposite bolts, for proper centering of the spiral wound component on the gasket seating surface. Whenever possible, it is recommended that a Style WR gasket be used in lieu of a style D gasket because of the obvious advantages of the outer solid metal gauge ring.
Style WR-RJ and WRI-RJ Spiral-wound gaskets are designed for use as a replacement maintenance item, of standard oval and octagonal ring joint gasket (RTJ).
These gaskets are available for NPS-1/2” to NPS-24 and pressure classes 150 to 1500.
Gasket thickness is .175” and Outer ring .125”.
Style WRI-RJ gaskets are fitted with an Inner ring .125” thick.