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Novus Spiral Wound Gaskets consist of a V-shaped metal strip spirally wound in combinationwith a soft, filler material. The metal strip providesoutstanding recovery, while the flexible fillerguarantees excellent sealing. Due to thiscombination of materials the spiral wound gasket is suitable for sealing under severely fluctuatingtemperature and pressure conditions. Dependingon the application, the spiral wound gasket can be specified with outer and/or inner rings.
Seating stressSpiral wound gaskets should preferably be mounted within the following gasket stress range to ensure a leak-proof connection.
Single side confined Both sides confined
Filler Gasket stress (20oC) Gasket stress (20oC)
Min Opt Max Min Opt Max(N/mm2) (N/mm2) (N/mm2) (N/mm2) (N/mm2) (N/mm2)
Graphite 50 95 180 50 122 400
PTFE 50 80 130 50 110 250
Non- 55 90 150 55 130 300Asbestos
Data / Specification Sheet • Novus Spiral Wound Gaskets
PropertiesSpiral wound gaskets are suitable foruse across a wide gasket stress range.
Spiral wound gaskets can be used toseal fluid pressures up to 250 bar andfrom cryogenic temperatures up toelevated temperatures of 1000oC.
Because of the robust design of thespiral wound gasket, it is simple toinstall without damage, although careshould be taken in transporting andinstalling large diameter gasketswithout inner or outer guide rings.
The outer guide ring simplifiesassembly and prevents blow out ofthe gasket.
By combining different windingmaterials and metals, the gasket can be tailored to suit a wide variety ofoperating conditions.
The gasket in non adhesive and iseasily removed.
Spiral wound gaskets will not damageflange surfaces.
Flange surfaceThe recommended surface roughnessof the flange faces, between which aspiral wound gasket is to be mounted,is 3.2 - 6.3 umRa (125-250 RMS),also referred to as a smooth finish.
TDS 25. Rev 2
Standard profiles
Type SGGasket with guide ringto act as compressionstop
Type RF-IRGasket with innerring
Type SG-IRStandard gasket withinner ring and outer rings
Type HX-RFor large diameterheat exchangers
Type RF1Gasket only
Type SG-RTJSpecial gasket forRTJ flanges
Type HX-RIRAs HX-R but withinner ring
Tel. +44 (0)1274 851273 Fax. +44 (0)1274 300303 www.flexitallic.eu Email. [email protected] : +27 (0) 11 915 0016/25/30 Fax : +27 (0) 11 915 0940 www.novussealing.co.za [email protected]
As the company’s products areused for a multiplicity of purposesand as the company has nocontrol over the method of theirapplications or use, the companyexcludes all conditions orwarranties, expressed or impliedby statute or otherwise, as totheir products and/or their fitnessfor any particular purpose. Anytechnical co-operation betweenthe company and the customer isgiven for customers assistanceonly, and without liability on thepart of the company.
Data / Specification Sheet • Novus Spiral Wound Gaskets
Special profilesIn the event of a graphite filled spiral woundpossibly causing an undesirable reactionbetween graphite and the medium to besealed, or of a possible medium contamination,the problem can be solved by using a spiralwound gasket with a GT-Zone.
The spiral wound element of a GT-Zone gasketconsists of outer windings of non-asbestos orceramic material with a central winding zonemade of graphite or PTFE (depending on theoperating conditions) to improve gas tightness.
The result is a spiral wound gasket which willnot pollute the sealed medium and givesexcellent gas tightness.
Profile selectionAdvantages of centering ring:
• Optimum gasket positioning between bolts
• Protection of the sealing element
• Additional security against gasket blow-out
• Acts as a compression limiter preventingoverloading and over-compression of thespiral wound element
• Prevents radial flow of soft fillers, such as PTFE
Advantages of inner ring:
• Prevents radial flow of soft fillers, such as PTFE
• Reduces turbulence, minimising flowresistance and crevice corrosion
• Acts as an additional heat shield when thespiral wound gasket is subjected to hightemperatures
• Inner and outer rings are particularlyrecommended for use on spiral woundgaskets exceeding class 600lbs, butspecifically recommended for hightemperatures and pressures to optimisereliable sealing performance
• For special flanges (male-female, tongueand groove etc) the type of spiral woundgasket selected will depend on the flangegeometry, operating conditions and boltspecifications. Novus specialists will bepleased to assist you were necessary.
Filler materialThe table below may be used to select thecorrect filler. It should be pointed out thatgraphite will be the optimum filler in mostcases. Only where graphite could causemedia pollution, or is not chemicallyresistant, should the use of another type of filler material be recommended, In suchcases, an alternative solution might be touse a gasket with a GT-Zone.
GraphiteGraphite is a universally applicable, highquality material with the followingproperties:
• Very good chemical resistance
• Resistance to high (fluctuating)temperatures and pressures
• Resistant to ageing
• Excellent gastightness
PTFEPTFE is a high quality synthetic material withthe following properties:
• Excellent chemical resistance
• Resistant to temperatures up to 250oC
• Resistant to ageing
• Excellent gastightness
Novus Hi-TempIs an aluminium silicate suitable forapplications at high operating temperatures.The material is characterised by poorgastightness and is therefore used incombination with graphite.
Material Temp (oC) Max. Op Gas ApplicationMin Max Pressure (Bar) Tightness
Graphite -200 550 250 Good Aggressive Media
PTFE -200 250 100 Good Aggressive Media
Non- -100 250 100 Good Liquids & GasesAsbestos
Novus -200 1100 100 Poor Very High Temp.Hi-Temp
Tel. +44 (0)1274 851273 Fax. +44 (0)1274 300303 www.flexitallic.eu Email. [email protected] : +27 (0) 11 915 0016/25/30 Fax : +27 (0) 11 915 0940 www.novussealing.co.za [email protected]
