Welcome To The Next Generation Of Sealing Technology - Flexitallic SOFC
Gasket Design CriteriaTable of ContentsPageWorldwide Customer Service Network2Introduction3Section I - Gasket SelectionSoft Cut Gaskets .Thermiculite .PTFE Products - Sigma .PTFE Products - Fluoroseal .Flexitallic Flexicarb .Compressed Fiber Gaskets .Sheet Materials Chemical Compatibility Chart .Insulating Sets .Metal Jacketed Gaskets .Spiral Wound Gaskets.Sizing Parameters for Spiral Wound Gaskets .Flexpro Gaskets .MRG Gaskets .Ring Type Joints .Specialized Ring Type Joints .Lens Rings .Weld Gaskets .467101213141518192229313233353637Section II - Joint Integrity CalculationsASME Boiler & Pressure Vessel Code Calculations .PVRC Method .383943Section III - Gasket InstallationBolt Torque Sequence .Troubleshooting .Metallic Gasket Materials .Useful Material Data .Bolting Data .Useful Technical Data .Torque Required To Produce Bolt Stress .Ordering Flexitallic Gaskets for Special Flange Designs .Metric Unit Conversions .Terms .4547495153545658596162Welcome to the Next Generation of Sealing Technology 1
Worldwide Customer Service NetworkOwned Manufacturing PlantsFlexitallic Ltd.Cleckheaton,Yorkshire, UKTel: 44 1274 851273Flexitallic Ltd.Rochdale, Lancashire, UKTel: 44 1274 851273Flexitallic L.P.Deer Park,TX, USATel: 1 281 604 2400Licensees - cont’d.Dragon Industrial ServicesPembroke, UKTel: 44 1646 622200Engineering & Chemical ProductionsLagos State, NigeriaTel: 234 1 804 3808Eriks BV.Rotterdam, NetherlandsTel: 31 72 514 1514Eriks Pte Ltd.SingaporeTel: 65 62 72 24 05Joint VenturesEquiter S.A. de C.V.Guadalajara, MexicoTel: 52 3 612 8483Branch Offices & WarehousesFlexitallic Ltd.Aberdeen, Scotland, UKTel: 44 1224 725241Shanghai Zone Sealing ProductsShanghai ChinaTel: 86 21 5812 8117LicenseesSpecialised Gaskets Pty. Ltd.Brisbane, AustraliaTel: 61 73 268 0666AGS Group Inc.Edmonton, Alberta, CanadaTel: 1 780 466 5050Capital Rubber & SpecialtyBaton Rouge, LA, USATel: 1 225 356 2451Cartec Sealing Technologies, Inc.Seoul, KoreaTel: 82 2 549 5441GB&G Die & Gasket Co., Inc.New Orleans, LATel: 800-522-9613GHX, Inc.Houston, TX, USATel: 1 713 222 2231Greenville Rubber & GasketGreenville, SC, USATel: 1 864 235 2574Henry Gallacher Ltd.Stockton, Teesside UKTel: 44 1642 750111Industrial Gasket & SupplyTorrance, CA, USATel: 1 310 530 1771James E. Dooley Co.Broomall, PA, USATel: 1 610 328 2720Lake Charles RubberLake Charles, LA, USATel: 1 337 433 1002Liaoning Cartec SealingTechnologies, Inc.Benxi City, ChinaTel: 86 414 481 3300Saudi Gasket FactoryJeddah, Saudi ArabiaTel: 996 2 665 2966Special Piping Material Ltd.Delta State, NigeriaTel: 234 53 254 767Note: Over 500 stocking distributors inover 40 countries strategically locatedto serve the world.2Welcome to the Next Generation of Sealing TechnologySpecialised Gaskets PTY Ltd.Auckland, New ZealandTel: 64 98284119
FLEXITALLIC GASKET DESIGN CRITERIAIntroductionFLEXITALLIC, the world’s leading manufacturer and supplier of static seals and the originator of the Spiral Wound Gasket, iscommitted to sealing solutions for today’s industry. With greater emphasis than ever before placed on joint tightness, more attention is focused toward variables associated with the integrity of the bolted gasketed joint. Flexitallic Gasket Design Criteria manual offers the engineer and end user assistance in meeting the goal of providing fundamentally sound static sealing practice.Developed and collated by Flexitallic’s worldwide team of engineers, this publication is the “engineer’s handbook” of static sealstechnology.Flexitallic has identified three factors which must be considered to achieve a leaktight joint Gasket Selection Gasket Design Gasket InstallationThe GasketA gasket is a compressible material, or a combination of materials, which when clampedbetween two stationary members prevents the passage of the media across those members.The gasket material selected must be capable of sealing mating surfaces, resistant to themedium being sealed, and able to withstand the application temperatures and pressures.Overcoming Flange ImperfectionsScoringsDistortiontroughHow Does It Work?A seal is effected by the action of force upon the gasket surface. This force which compresses the gasket, causes it to flow into the flange macro and micro imperfections. Thecombination of contact stress, generated by the applied force between the gasket and theflange, and the densification of the gasket material, prevents the escape of the confined fluidfrom the tionsFlange ImperfectionsOn seating, the gasket must be capable of overcoming the macro and micro imperfections.Macro defects are imperfections such as flange distortions, non-parallelism, scoring,troughs, while superficial imperfections such as minor scratches and minor scores are considered micro imperfections.BoltLoadHydrostaticEnd ForceForces On The GasketIn order to ensure the maintenance of the seal throughout the life expectancy of the assembly, sufficient stress must remain on the gasket surface to prevent leakage. The residual boltload on the gasket should at all times be greater than the hydrostatic end force acting againstit.The hydrostatic end force is the force produced by the internal pressure which acts to separate the flanges.Blow OutForceGasketConsiderations For Gasket SelectionsMany factors should be considered when selecting a gasket to ensure its suitability for theintended application. Gasket properties as well as flange configuration and applicationdetails are part of the selection process.Welcome to the Next Generation of Sealing TechnologyInternal Pressure is exertedagainst both the flange and thegasket. 3
SECTION IGasket SelectionGaskets can be classified into three categories: soft cut, semi-metallic and metallic types.The physical properties and performance of a gasket will vary extensively, depending on the type of gasket selected and the materialsfrom which it is manufactured.Physical properties are important factors when considering gasket design and the primary selection of a gasket type is based on the following: Temperature of the media to be contained Pressure of the media to be contained Corrosive nature of the application Criticality of the applicationSoft CutSheet materials are used in low to medium pressure services. With careful selection thesegaskets are not only suitable for general service but also for extreme chemical services andtemperatures.Types: Compressed Fiber Sheets, PTFE, Biaxially Orientated Reinforced PTFE, Graphite,Thermiculite, Insulating Gaskets.Semi-metallicThese are composite gaskets consisting of both metallic and non-metallic materials. Themetal provides the strength and the resilience of the gasket and the non-metallic componentprovides the conformable sealing material. These gaskets are suitable for low and high pressure and temperature applications. A wide range of materials is available.Types: Spiral Wound Gaskets, Flexpro Gaskets (covered serrated metal core), MetalJacketed Gaskets, MRG’s (metal reinforced gaskets).MetallicThese gaskets can be fabricated in a variety of shapes and sizes recommended for use in highpressure/temperature applications. Except for weld ring gaskets, high loads are required toseat metallic gaskets, as they rely on the deformation or coining of the material into theflange surfaces.Types: Ring Type Joints, Lens Rings, Weld Rings, Solid Metal Gaskets.4Welcome to the Next Generation of Sealing Technology
Gasket SelectionService Class 300YesNoCritical ServiceRTJ type flange or Class 600YesFlange intendedfor RTJ typeYesUseRTJNoUseSWG,Flexpro, orWeld RingNoYesNoCritical ServiceYesUseSWG,Flexpro, orWeld RingNoUse LS,SWG,Flexpro,MRG, orWeld RingUse Soft CutUseSWG,Flexpro,MRG,Weld Ring,Thermiculite 815,or ST/RGS3Select sealing material and metal type (when appropriate) on basis of service, temperature, and nature of medium.Soft cut gaskets should always be of the minimum thickness consistent with the style of the flanges to be sealed, andcompatible with the medium.Welcome to the Next Generation of Sealing Technology 5
Soft Cut GasketsCompressed Asbestos Fiber(CAF) gaskets served industry’sneeds for many years. With theshift to Comrpessed Fiber gaskets, gasket manufacturers havedeveloped a myriad of replacement products. Some of the initial materials developed provedinferior to their asbestos basedpredecessors in regard to temperature, chemical resistance, creepresistance and sealing characteristics.More recently Flexitallic hasdeveloped compressed fiber gasket sheet products approaching,and in some instances surpassingthe capabilities of asbestos sheetgaskets. Some of these productshave been fiber reinforced grades, manufactured by the traditional calendering or sheeter process. Otherproduct ranges are fiber-free and some of these materials have exceptionally good properties which exceedthe capabilities of CAF.Flexitallic Thermiculite is a versatile gasket material based upon the exfoliated vermiculite mineral. Theproduct is available with a metal reinforced core or coreless and is designed for use at temperatures whichexceed the capability of graphite based sheets. The temperature capability of CAF is also exceeded byThermiculite.The Flexitallic Sigma range of biaxially orientated PTFE products has superb chemical resistance, farexceeding that of CAF. These materials can be used at temperatures from cryogenic to 260 C (500 F).Being intrinsically clean they are especially suitable for use in the food, pharmaceutical and electronicsindustries.Flexicarb is the name given to Flexitallic’s range of graphite based products. The range includes graphitefoil as well as graphite laminates which contain reinforcing metal cores to overcome the fragility of thenon-reinforced foil. Graphite products have excellent stress retention properties and are resistant to mostchemical media with the exception of strong oxidizing agents. Reinforced Flexicarb sheets are the standard sealing product for many arduous applications in the petrochemical and refining industries.The Flexitallic SF product ranges are rubber bound, fiber reinforced sheets made by the traditional calendering or sheeter process. A wide range of fiber types are used, often in combination, ranging from cellulose, rockwool and glass to aramid and carbon.Soft cut gasket sheets are typically used in Class 150 or Class 300 flanges. The temperature capability ofthe fiber/rubber products is highly thickness dependent, with thin gaskets having a wider service envelopethan thicker ones.6Welcome to the Next Generation of Sealing Technology
Thermiculite Exclusive to Flexitallic, this revolutionary material comprised of chemically and thermallyexfoliated vermiculite simulates the structure of exfoliated graphite, with one notable exception – it maintains integrity through a wide range of extreme temperatures. Vermiculite’sthin, flexible, soft plates can be exfoliated like graphite. They retain the sealability and lowporosity of graphite, but unlike graphite, Flexitallic’s Thermiculite sheet materials will notoxidize at high temperatures.Graphite’s stress-loss due to oxidation has led to many examples of gasket failure.Independent testing of industrial grade graphite indicates a temperature limit of 650 F(340 C) for continuous service over 5 years. Thermiculite however is thermally stable andmaintains its integrity at temperatures up to 1800 F (982 C), protecting against thermal oxidation (see graph on page 8). Independent testing at TTRL (Tightness, Testing, andResearch Laboratory) in Montreal illustrates Thermiculite’s excellent sealing properties.Vermiculite’s thin, flexible, soft platescan be exfoliated like graphite. Theyretain the sealability and low porosityof graphite, but Flexitallic’s newThermiculite sheet gaskets will notoxidize at high temperatures.Product RangeFlexitallic has developed two exceptional sheet materials – Thermiculite 715 and 815 – that demonstrate the broad range of chemicaland temperature resistance of the vermiculite mineral. Both materials are extremely versatile, fire safe, and not susceptible to oxidation.Performance SeriesThermiculite 715Part A100000High performance coreless sheet material (i.e. nometallic reinforcement). Generally replacescompressed fiber sheet line – SF2401, 2420,3300, 5000 – and graphite sheet. Available inthicknesses of 1/32”, 1/16” and 1/8” in cut gaskets and 60” x 60” sheet.Part B2Part B310000Gasket Stress, Sg (psi)With its wide service capability, Thermicuulite715 presents an opportunity for gasket standardization and inventory consolidation.Filled Markers - 400 psiUnfilled Markers - 800 psiPart B1a 0.2431000Tp Max 92899Gb 1031To Gs 9.68TH7151001101000100100001000001000000Tightness Parameter, 3000S100003,1585,5297,2229,678Thermiculite 715 Coreless SheetWelcome to the Next Generation of Sealing Technology 7
Thermiculite Critical Service SeriesThermiculite 815High temperature sheet reinforced with a 0.004” 316 stainless steel tanged core. Available inthicknesses of 1/32”, 1/16”, and 1/8” in meter by meter (standard) and 60” x 60” sheet. Cutgaskets available in all shapes and sizes.Time Since Start of Test (days)1003690121518212427303336394245Each specimen heldsuccessively for 3 days ateach temperature and thechange of weight recorded80Cumulative Weight Loss (%)970BEST EXFOLIATEDGRAPHITE TESTED60WORST EXFOLIATEDGRAPHITE TESTED50403020THERMICULITESHEET 5001022 1112 1202 1292 1382 1472 1562 1652550 600 650 700 750 800 850 900Thermiculite 815 is the originalgrade developed in the entirerange of Thermiculite series.This product has proven itself asan effective long-term sealingsolution in the most versatiledemanding industrial sealing Thermiculite 815 Tanged Sheetapplications.Thermiculite 815 chemical compatibility exceeds that of graphite andwill successfully seal up to 1800 (982 C). Thermiculite’s high temperature capabilities make it ideal for use in combustion engineexhaust, nitrogen fertilizer manufacturing, steam, and much more.Unlike graphite, Thermiculite resistance to galvanic corrosion willmake it an excellent candidate for seawater and offshore cooling applications.Temperature FTemperature C100000Cumulative Iso-thermal weight loss results for the best andworst exfoliated graphite testedGasket Stress, Sg (psi)1009080% Load Retention7060Filled Markers - 400 psiUnfilled Markers - 800 psiPart B1Part B2Part B3Part A10000a 0.200Gb 1,906100050Gs sed Time (Hours)10000100010000Tightness Parameter, Tp100000GbaGsTPMINTPMAX1,9060.24561858,645Graphite @ 700 F (370 C)S100S1000S3000S10000Graphite @ 950 F (510 C)4,7887,5889,40012,0261000000Thermiculite @ 700 F (370 C)Thermiculite @ 950 F (510 C)This graph illustrates that, unlike graphite, the loadloss at operational temperatures does not increasewith time.8Room Temperature Tightness (ROTT) behavior characterization(Refer to page 43 for new method for determining factors.)The above graphs are taken from the actual tests performed by TTRL.Welcome to the Next Generation of Sealing Technology
Thermiculite Sheet Property SummaryThermiculite 715Thermiculite 815TypeCoreless0.004” 316SS TangedReinforcedColorLight BrownGolden Brownin. (mm)1/16 (1.5)1/16 (1.5)3108 (1.73)75 (1.16) facing onlyMaterial DescriptionPropertiesThicknessDensitylb/ft (g/cc)ASTM F 36 Compressibility%1244ASTM F36 Recovery%419ASTM F152 Cross Grain Tensile Strengthpsi (MPa)1305 (9)n/aASTM F38 B Creep Relaxation 1/32”%20.623.5ASTM F37 Liquid LeakageFuel A 10 psi, Stress 1000 psiml/hr1.4n/aDIN 3754 Gas Permeabilityml/min 0.10.13BS 7531 Stress Retention @ 570 F (300 C)psi (MPa)3,630 (25)4500 (31)ASTM F146 Thickness Increase IRM 903%1.4n/aASTM F146 Thickness Increase Fuel B%0.2n/aASTM F146 Weight Increase IRM 903%17.7n/aASTM F146 Weight Increase Fuel B%11.3n/aMaximum Temperature1 F ( C)850 (454)1800 (982)Maximum Pressure1psi (bar)2030 (140)2900 (200)3.02.0Gasket ConstantsASME mASME Ypsi (MPa)1,500 (10.4)2,500 (17.25)PVRC Gbpsi (MPa)1,031 (7.1)1,906 (13.1)0.2430.29.68 (0.07)456 (3.1)92,89958,645PVRC aPVRC Gspsi (MPa)Tpmax1 Temperature and pressure guides cannot be used simultaneously and do not apply to all thicknesses.Welcome to the Next Generation of Sealing Technology 9
PTFE Products - Sigma Flexitallic Sigma offers outstanding chemical resistance while the unique manufacturing process results in a biaxially fibrillated structureensuring high seal integrity in the most demanding applications.Pure PTFE sheet products are highly susceptible to creep relaxation which can be reduced by the incorporation of selected fillers (FilledPTFE). The maximum reduction in creep is achieved by combining these fillers in a biaxially orientated structure such as Sigma.Flexitallic Sigma materials are inherently clean, making them suitable for use in industries where product contamination may be of concern such as food, pharmaceuticals and electronics. The components of the Flexitallic Sigma range comply with the requirements of FDAregulations and the materials’ outstanding chemical resistance make them suitable for sealing virtually every chemical medium across thewhole pH range (0 - 14).Sigma products give unparalleled levels of sealing performance, especially when compared to conventional materials used in applicationsinvolving aggressive chemical media. These comparisons are supported by data generated by recognized, independent, international bodies in the field of static sealing. Sigma products are ideally suited for applications where seal integrity is paramount, an important consideration where stringent emission controls may be in force.All products in the Flexitallic Sigma range are capable of sealing from cryogenic temperatures up to 500 F (260 C). For intermittent useeven higher temperatures can be tolerated. Pressures from 1230 psi (8.5 MPa) down to vacuum can be accommodated. Furthermore,applications involving low gasket stresses such as glass lined, plastic and ceramic flanges, will not result in loss of sealing performance.The Sigma range of products has been engineered to be userfriendly: Materials can be cut easily using conventional toolsand techniques Complex geometric shapes can be accommodated,including narrow cross sections Gaskets are easy to install and remove All products are non-toxicProduct RangeSigma 500 - Sheet material with higher compression specifically formulated for use on glass lined, plastic or ceramic flanges. Also suitable for use on flanges which are non-parallel, damaged or distorted. Compatible with acids and alkalis at all but the highest concentrations. Enhanced compressibility is achieved by the incorporation of hollow glass microspheres as the inorganic filler. Sigma 500 is listed in the Chlorine Institute Pamphlet 95.Sigma 511 - Standard compression sheet material reinforced with a silica filler. Intended for use with concentrated acids (except hydrofluoric acid) and with most general aggressive chemicals: also suitable for medium concentrations of alkalis.Sigma 522 - These products have rigid cores of biaxially reinforced PTFE with soft, conformable surface layers of pure PTFE. Designedfor use where low bolt loading is available.Sigma 533 - Standard compression sheet material reinforced with barytes (barium sulphate) filler. Sigma 533 is the preferred choice forsealing concentrated alkalis and is also compatible with Aqueous Hydrofluoric Acid. Restricted resistance to concentrated mineral acids.Sigma 533 is listed in the Chlorine Institute Pamphlet 95.Sigma 588 - Most compressible PTFE sheet without filler; biaxially orientated PTFE core with soft surfaces for higher, controlled compressibility.Sigma 599 - Specially formulated PTFE sheet with hollow glass microspheres for higher compression.10Welcome to the Next Generation of Sealing Technology
PTFE Products - Sigma PropertiesSIGMA 500SIGMA 511SIGMA 522SIGMA 533SIGMA 588SIGMA 599Material DescriptionComposition PTFEColorPTFE, GlassMicrospheresPTFE, SilicaPTFE, BariumSulfatePTFE, BariumSulfatePTFEPTFE, GlassMicrospheresBlueFawnWhite w/Off whitecoreOff whiteWhiteWhite w/Blue corePropertiesThicknessin (mm)1/32 (0.8)1/32 (0.8)1/16 (1.6)1/32 (0.8)1/16 (1.6)1/16 (1.6)87 (1.4)137 (2.2)125 (2.0)180 (2.9)70 (1.1)86 (1.4)ASTM F36 Compressibility%421030115538ASTM F36 Recovery%4044254624391740 (12.0)2175 (15.0)1479 (10.2)2260 (15.6)1390 (9.6)1810 (12.5)ASTM F38-B Creep Relaxation%21.223.94816.85030ASTM F37-A Sealability1mL/hr0.120.420.660.420.060.12DIN 3754 Nitrogen Gas lb/ft (g/cc)ASTM F152 Cross Grain Tensile Strengthpsi (MPa)Maximum Pressure940 - 1230 psi (depending on thickness)Maximum Temperature500 FGasket ConstantsASME m1.41.41.41.41.41.4ASME Ypsi (MPa)1885 (13.0)2320 (16.0)1885 (13.0)2320 (16.0)1595 (11.0)1885 (13.0)4209472115--PVRC a (1/16”)0.8040.3560.250.382--PVRC Gs 28130E21M4F456110E11M5PVRC Gb (1/16”)psiProduct DesignationASTM F104 Line ents in all SIGMA grades comply with FDA requirements and can be cleaned foroxygen service.ApplicationsAcids & caustics @moderate concentrations, Hydrocarbons,Solvents, HydrogenPeroxide, Low boltloads, Glass linedflanges, In place ofenvelope gasketsGeneral service,Strong acids,Sulfuric acid,Solvents,Hydrocarbons,Steam, Chlorine,General ServiceHydrofluoric Acid,Warped or glasslined flanges, Inplace of envelopegasketsStrong caustics,Pharmaceutical &Moderate acids,Food service, GlassChlorine,Lined, FRP,Hydrocarbons,Ceramic & PlasticFood/pharmaceutical, flanges, Distorted &Aqueous HFDamaged flanges;(Hydrofluoric Acid) @HFmax. conc. 49%,Aluminum FluorideGlass lined & Plasticflanges, Replaceenvelope gaskets,Strong acids toModerate causticsAnhydrous HF, Fluorine, Molten alkali metals, i.e. molten sodium, Potassium, Lithium, Bromine trifluoride, Chlorine trifluoride, moltenalkali, metals, Boron Trifluoride, Chlorine Trifluoride, Fluorine dioxideMisapplications1Hydrogen fluoride gas, Hydrogen fluorideAluminum fluoridegas, Hydrofluoricacid, Black & greensulfate liquors,Caustic sodaSame asSigma 533Aqueous HF(Hydrofluoric Acid)@ conc. higherthan 49%Hydrogen fluoride gas,Aluminum fluorideFuel A 10 psi; Gasket Stress 1000 psiWelcome to the Next Generation of Sealing Technology 11
PTFE ProductsFluorosealFluoroseal is an expanded, pure PTFE sealing material. Supplied in the form of ahighly conformable, flexible strip, it is ideal for use in applications involving nonstandard flanges. This material offers both versatility and convenience and is therefore often used as a backup sealing option in situations where conventional gasketsare not immediately available.Flexitallic Fluoroseal has outstanding chemical resistance and is inherently clean,making the product particularly suitable for sealing against aggressive media or insituations where feedstock contamination may be of concern.The presence of an adhesive backed strip simplifies installation in large or complexflange applications, such as air conveying and solvent recovery systems.Widths and Thicknesses of Fluoroseal At Full CompressionSealant ThicknessSealant WidthCompressed ThicknessCompressed Width1/16” (1.5mm)3/32” (2.0mm)3/32” (2.5mm)5/32” (4.0mm)5.0mm (3/16”)5.0mm (3/16”)6.0mm (7/32”)6.0mm (1/4”)6.0mm (1/4”)1/8”3mm (1/8”)3/16” (5mm)1/4” (7mm)3/8” (10mm)1/2” (12.5mm)9/16” (14mm)11/16” (17mm)3/4” (19mm)1” (25mm)0.010” (0.3mm)0.015” (0.4mm)0.018” (0.45mm)0.022” (0.55mm)0.031” (0.8mm)0.031” (0.8mm)0.039” (1.0mm)0.049” (1.25mm)0.049” (1.25mm)0.24” (6mm)0.40” (10mm)0.50” (13mm)0.80” (20mm)0.95” (24mm)1.00” (22mm)1.14” (29mm)1.34” (34mm)1.77” (45mm”)Fluoroseal is suitable for cryogenic application, and for temperatures up to 500 F (260 C).Typical applications:Hydraulic systems, pneumatic systems, water supply systems, ventilation ducts, fan housing,fume ducts, engine case doors etc.Bolt Forces per Unit Length of SealFluorosealUniversal Joint SealantNominal SizesGas Tight (lbf/in.)Width (in.)1/83/161/43/81/25/83/4Water Tight 5401680196025202800294029403360Width (in.)Spool Length 0390390390420420Gas tight is based on compressed air at 600 psi.Water tight is based on water at 30 psi.12Welcome to the Next Generation of Sealing Technology
Flexitallic Flexicarb The Flexitallic Flexicarb range of sheet sealing materials is manufactured from high purity exfoliated graphite flake, and is availablewith or without a reinforcing metallic core. The “standard” product range is based upon graphite with a minimum carbon content of98% and, for nuclear applications, graphite with a minimum carbon content of 99.85% is available. The graphite foils can be attachedto the reinforcing core by mechanical means or by the use of selected adhesives.Flexicarb laminates are particularly suited for applications involving moderately high temperatures and pressures in a wide range ofmedia. They are widely used in demanding industrial applications and in the petrochemical/refining industries. Because these products do not contain any rubber or polymeric binders they have the highest levels of stress retention, ensuring that gasket stress appliedduring assembly is maintained during service.Graphite based products are resistant to most industrial chemicals but are susceptible to attack by oxidizing agents such as nitric acid.Sulfuric acid can also attack graphite at certain combinations of concentration and temperature. When selecting a graphite laminate foruse in chemical service, consideration must be given to any possible reaction between the chemical medium and the reinforcing metallic core.In air or in services where oxygen is present, graphite can burn away at high temperatures as it is converted to oxides of carbon. Therate at which this occurs depends on the graphite purity, temperature and the concentration of oxygen present. In a well bolted flangeonly the inner edge of the gasket will be exposed to oxygen in the pipe; the graphite will burn away very slowly with service life beingaffected by the land width of the gasket. In high temperature applications where the fluid being sealed does not contain oxygen, consideration must be given to possible attack of the graphite byRequiredMaximum Service Temperatureoxygen from the external atmosService Lifephere surrounding the flange.Years C FFor long term service, work by13independent testing has shown5that maximum service tempera10ture should be m
FLEXITALLIC GASKET DESIGN CRITERIA Introduction FLEXITALLIC, the world's leading manufacturer and supplier of static seals and the originator of the Spiral Wound Gasket, is committed to sealing solutions for today's industry. With greater emphasis than ever before placed on joint tightness, more atten-
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
Silat is a combative art of self-defense and survival rooted from Matay archipelago. It was traced at thé early of Langkasuka Kingdom (2nd century CE) till thé reign of Melaka (Malaysia) Sultanate era (13th century). Silat has now evolved to become part of social culture and tradition with thé appearance of a fine physical and spiritual .
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Chính Văn.- Còn đức Thế tôn thì tuệ giác cực kỳ trong sạch 8: hiện hành bất nhị 9, đạt đến vô tướng 10, đứng vào chỗ đứng của các đức Thế tôn 11, thể hiện tính bình đẳng của các Ngài, đến chỗ không còn chướng ngại 12, giáo pháp không thể khuynh đảo, tâm thức không bị cản trở, cái được
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. Crawford M., Marsh D. The driving force : food in human evolution and the future.
Le genou de Lucy. Odile Jacob. 1999. Coppens Y. Pré-textes. L’homme préhistorique en morceaux. Eds Odile Jacob. 2011. Costentin J., Delaveau P. Café, thé, chocolat, les bons effets sur le cerveau et pour le corps. Editions Odile Jacob. 2010. 3 Crawford M., Marsh D. The driving force : food in human evolution and the future.
