gaskets
TRANSCRIPT
Prepared by:SHAHID HUSSAIN STAFF TRAINEE (UREA)
WHAT IS GASKETS
INTRODUCTION
GASKET ARE USED TO CREATE A STATIC SEAL B/W TWO STATIONARY MEMBERS OF A MECHANICAL ASSEMBLY AND TO MAINTAIN THAT SEAL UNDER
OPERATING CONDITIONS WHICH MAY VARY DEPENDENT UPON CHANGES IN PRESSURE AND
TEMPERATURES .
A Gasket Is A Mechanical Seal That Fills The Space Between Two Mating Surfaces, Generally
To Prevent Leakage From Or Into The Joined Objects While Under Compression. Gaskets Allow "Less-than-perfect" Mating Surfaces On Machine
Parts Where They Can Fill Irregularities.).
FORCES ACTING ON GASKETED JOINT
THREE BASIC FORCES ACTING ON A GASKETED JOINT . COMRESSION FORCE SHOULD BE MORE THAN ALL OTHER FORCES
A : BOLT LOAD
IT IS THE ASSEMBLY LOAD WHICH PRODUCED BY THE BOLTS OR CLAMPS AND IS TRANSMITTED AS A COMRESSIVE STRESS ON THE GASKET .THIS FORCE FLOWS THE GASKET MATERIAL IN TO SURFACE IMPERFECTION TO FORM A SEAL.
C : HYDROSTATIC END FORCE
HYDROSTATIC END FORCE IS PRODUCED BY INTERNAL PRESSURE AND TENDS TO SEPARATE FLANGES WHEN THE SYSTEM IS PRESSURIZED.
B : INTERNAL PRESSURE
INTERNAL PRESSURE IS THE FORCE CONTINUALLY ACTING ON THE PORTION OF GASKET EXPOSED TO INTERNAL PRESSURE , WHICH TENDS TO BLOW OUT THE GASKETS FROM THE JOINT.
HYDROSTATIC END FORCE
BLOW OUT PRESSURE
GASKET
BOLT LOAD
• OTHER FACTORS
• TEMPERATURE & PRESSURE
THERE ARE OTHER SHOCK FORCES WHICH ARE CREATED DUE TO TEMPRATURE AND SUDDEN CHANGE IN TEMPRATURE AND PRESSURE RESULTING A THERMO-MECHANICAL EFFECT EXPANDING OR CONTRACTING THE MATERIAL.
MEDIUM THE LIQUID OR GAS IS TO SEAL
• GENERAL CONDITIONS
TYPES OF FLANGES , FLANGE SURFACE FINISH BOLT MATERIAL
NON METAL GASKETS
METAL GASKETS / MACHINED GASKETS
METAL JACKETED GASKETS
SPIRAL WOUND GASKETS
METAL GASKETS
NON METAL GASKETS
• COMPRESSED ASBESTOS FIBER CAF
NATURAL ASBESTOS FIBER ARE NOT WELL SUITED FOR FORMING STRONG SHEETS OR CLOTH. NATURAL ASBESTOS IS REINFORCE WITH COTTON FINE BRASS, STEEL ,STAINLESS STEEL, INCONEL WIRES . ASBESTOS IS IMPREGNATED WITH NATURAL RUBBER , NEOPRENE, BUNA S , SYNTHETIC BINDERS , SBR , NBR , GRAPHITE FOR DIFFERENT QUALITIES AND USES.
NON METAL GASKETS ARE MOST WIDELY USED VARIOUS MATERIALS USED FOR NON METTALIC GASKETS ARE NATURAL RUBBER- SBR – NEOPRENE – BUNA-N – VITON SILICONES – RUBBER - EPDM – CERAMIC FIBER – GRAFOIL – PTFE – ASBESTOS & NON-ASBESTOS ETC
GRAPHITE
ADVANTAGES OF ASBESTOS
• ABILITY TO WITH STAND HIGH TEMPERATURE 550 C• IT IS THE CHEMICALLY INERT AND ATTACKED ONLY BY STRONGE MINERAL ACIDS.• THE USE OF LONGER FIBER WILL RESULT IN A MATERIAL WITH
HIGH TENSILE STRENGTH , BETTER COMPRESSIBILITY , GREATER RESISTANCE TO FLOW UNDER CONDITIONS OF HEAT AND STRESS. COMPRESSED ASBESTOS SHEETS ARE USUALLY 65 TO 70 % FIBER AND REMAINING IS BINDER COMPOUNDING AGENT.
DEPENDING OF COMPOUNDING AGENTS MAY BE USED FOR
SUPER HEATED AND SATURATED STEAM ,
AIR , GAS , ALKALIES SOLUTION , WEEK ACIDS AMMONIA , BRINE , OIL , CHEMICAL SOLUTION AND
PETROLEUM DISTILLATE
APPLICATIONS
COMPRESSED ASBESTOS GASKETS
TYPE DISCRIPTION COLOUR SERVICE RATING
Klingerit 3 A Asbestos Fiber + SBR Red / BrownSteam + Compressed Air +
Gases T 550 C
P 130 Bar
Klingerit 3 A
universal Asbestos Fiber + NBR Blue Oil Service T 550 c
P 140 Bar
Klingerit Oilit 3 A Asbestos Fiber + NBR BlackOil & petro chemical +
Refregrents T 500 C
P 130 Bar
Klinger WB 1 Asbestos Fiber + SBR Yellow Automotive Industry T 350 C
Klinger Mark 100 Asbestos fiber + SBR Grey Oil & Petrolling Industry T 510 C
Klinger 61 B Asbestos Fiber + SBR Grey Use for General purpose T 350 C
P 35 Bar
Klingerit Acidic Asbestos + special Binder whiteAcidic service Ceramic & Glass
flanges T 450 c
P 20 Bar
Klingerit DG1 Asbestos + special cr binder Red / brownfluid oils & petrolling &
Aerospace T 550 c
P 125 Bar
Klinger sil C 4400Asbestos Fiber + Natural
rubber Green General Purpose T 400 c
P 100 Bar
TYPES OF NON METAL GASKETS
ACCORDING TO SHAPE WISE
INSIDE BOLT CIRCLE TYPE FULL FACE TYPE
FULL FACE TYPE
INSIDE BOLT CIRCLE TYPE
IN THIS TYPE PRIPHERY OF THE GASKET IS LOCATED BY THE BOLTS .OUTSIDE DIAMETER OF GASKET IS EQUAL TO BCD LESS DIA OF BOLT & INSIDE DIA IS EQUALTO FLANGE.INSIDE BOLT CIRCLE GASKETS ARE GENERALLY USED FOR RAIS FACE FLANGES
OUTSIDE DIA IS SIMILER TO THAT OF THE FLANGE AND HAS A SERIES OF HOLES CORRESPONDING THE NUMBER AND BCD OF THE BOLTS.ID IS EQUAL TO THE ID OF FLANGE.FULL FACE TYP GASKETS ARE GENERALLY USED FOR FLAT FACE FLANGES
• METAL GASKETS
METAL GASKETS ARE AVAILABLE IN MANY FORMS INCLUDIND
• SOLID METAL GASKETS T HAT REQUIRE VERY SMOOTH PLAIN SURFACE FINISH AND HIGH CLAMPING FORCE FOR SEALING PURPOSE.
• COMBINITION WITH SOFT FILLER S SUCH AS JACKETED & SPW GASKETS THAT CAN TOLERATE GREATYER SURFACE ROUGHNESS AND REQUIRE LESS COMPRESSIVE FORCE.
• SELF SEALING LIGHT CROSS SECTION GASKETS WHICH REQUIRE MINIMUM CLAMPING FORCE FOR EFFECTIVE SEALING.
4. CONSTRUCTION 4. CONSTRUCTION FLAT METAL GASKET
4. CONSTRUCTION 4. CONSTRUCTION RING JOINT GASKET
4. CONSTRUCTION 4. CONSTRUCTION LENS GASKET
4. CONSTRUCTION 4. CONSTRUCTION BRIDGEMAN GASKET
TYPES OF METAL GASKETTYPES OF METAL GASKETTYPES OF METAL GASKETTYPES OF METAL GASKET
PLAIN FLAT METAL GASKETS
FLAT METAL GASKETS ARE BEST SUITED FOR ‘VALVE BONNETSAMMONIA FITTING , HEAT EXCHANGER , HYDRAULIC PRESSES TONGUE & GROOVE JOINTS.THEY CAN BE USED WHERE SUFFICIENT CLAMPING FORCE IS AVAILABEL SO THAT GASKET METAL CAN FLOW INTO THE IMPERFECTIONS OF THE SEATING SURFACE
THE HARDNESS OF THE FLANGE TO PREVENT DAMAGE TO SEATING SURFACE. THEY CAN BE PRODUCED FROM ANY MATERIAL AVAILABLE IN SHEETS.
RING JOINT GASKETS
THESE GASKETS BASICALLY MANUFACTURED IN OVAL OCTAGONAL CROSS SECTION AND ARE USED FOR VERY HIGH PESSURE UPTO 500 PSI.
THE OCTAGONAL CROSS SECTIONGASKETS HAS HIGHER EFFICIENCYTHAN OVAL CROSS SECTION.
THESE GASKETS ARE DESIGNED FOR USE IN HIGH TEMPERATURE AND HIGH PRESSURE ENVIRONMENTS. THESE GASKETS MUST PERFORM IN VERY DEMANDING APPLICATIONS OFTEN IN THE PRESENCE OF STRONG CORROSIVE AGENTS.
MADE FROM SOLID METAL AND MACHINE FORMED TO THE DESIRED DIMENSIONS AND SHAPE THEY ARE COMMONLY FOUND IN REFINERIES, OIL AND GAS FIELDS AND IN CHEMICAL PROCESS PLANTS. THEY ARE AVAILABLE IN A VARIETY OF MATERIALS. IT IS STRONGLY RECOMMENDED THAT THE GASKET METAL BE SOFTER THAN THE FLANGE MATERIAL
SEALING SURFACE ON RING JOINT GASKETS GROOVES MUST BE SMOOTHLY FINISHED TO 63 MICRO INCHES AND BE FREE FROM OBJECTIONABLE RIDGESTOOLS OR CHATTER MARKS.THEY SEAL BY AN WEDGING ACTION AS COMRESSIVE FORCES ARE APPLIED. RING HARDNESS SHOULD BE LESS THAN FLANGE
CROSS SECTION OF RING JOINT GASKETS
Weld ring Round ring-joint
oval RING joint
octagonal ring-joint
pressure engergized ring-joint
pressure engergized ring-joint
Delta ring-joint
Lens ring-joint
Double cone ring-joint
LENS TYPE GASKETS
A LENS TYPE GASKETS IS A LINE CONTECT SEAL WHICH IS USED IN HIGH PRESSURE PIPING SYSTEM AND ON PRESSURE VESSEL HEADS. LENS CROSS SECTION IS A SPHERICAL ( CONVEX ) GASKETS SURFACE AND REQUIRE SPECIAL MACHINING ON THE FLANGES.THESE GASKETS WILL SEAL WITH SMALL BOLT LOAD SINCE THE CONTACT AREA IS VERY SMALL AND GASKETSSEATING PRESSURE IS VERY HIGH.
GASKET MATERIAL SHOULD BE SOFTER THAN FLANGE. FLANGES SEATING .SURFACE FINISH SHOULD NOT BE LESS THAN 63 MICRO INCHES
ADVANTAGES OF LENS GASKETS
FOLLOWING ADVANTAGES ARE ASSOCIATED WITH LENS GASKETS
• DUE TO SPECIAL DESIGN OF FLANGE FOR LENS GASKETS LEAKAGE CAN BE EARLIER DETECTED.
• LENS GASKETS ARE SELF ALIGNING AS COMPARED TO RING JOINT GASKETS
• CAN BE USED FOR HIGH PRESSURE & HIGH TEMPRETURE & CORROSIVE SERVICE
• THERE IS NO GROOVE ON THE FLANGE WHICH HAS THE ADDITIONAL ADVANTAGE FOR CORROSIVE SERVICE E.G CARBAMATE SOLUTION
• BECAUSE OF EARLIER LEAKAGE DETECTION LEAKAGE REMOVAL MEASURES CAN BE PLANNED EARLIER RESULTING SAVING A SHUT DOWN OR PRODUCTION LOSS
• DUE TO LINE CONTACT FOR SEALING A SMALL BOLT LOAD IS REQUIRED BECAUSE SEALING AREA IS VERY SMALL .REMEMBER SEALING PRESSURE IS VERY HIGH
BRIDGEMAN GASKETS
THE BRIDGEMAN GASKET IS A PRESSURE ACTIVATED GASKET FOR USE ON PRESSURE VESSEL HEADS VALVE BONNETSFOR PRESSURE OF 1500 PSI.AND ABOVE.CROSS SECTION OF THE GASKETS IS SUCH THAT INTERNAL PRESSURE FORCES ITAGAINST THE CONTAINING SUFACEMAKING A SELF ENERGIZED SEAL.
THESE ARE FREQUENTLY SILVER ORLEAD PLATED TO PROVIDE SOFTER SURFACE WHICH MINIMIZE THE REQUIRED FORCE TO FLOW GASKETMETAL INTO FLANGE SURFACE.
gasketsgaskets
THESE GASKETS ARE SPECIALLY DESIGNED FOR HEAT EXCHANGERAUTO CLAVES , PRESSURE VESSELS , VALVE BONNETS AND DIFFERENT SERVICES.THE GASKETS COMPRISE OF A SOFT PLIABLE FILLER CORE AND ARE SURROUNDED BY A METAL JACKET.“ METAL JACKET “ PROVIDES MECHANICAL STRENGTH AND IS SELECTED TO SUIT THE SERVICE AND TEMPERATURE..
JACKETED GASKETS ARE SUPPLIED WITH ASBESTOS OR NON ASBESTOS , CAF. HIGH TEMPERATURE FILLER. STANDARD FILLER ARE NORMALLY SUFFICIENT FOR APPLICATION UPTO 900DEG FGRAFOIL , PTFE , CAN BE USED AS SOFT FILLER FOR HIGHER TEMPERATURE.STANDARD METALS USED TO MAKE JACKETED GASKETS REGARDLESS OF TYPES ARE
ALUMINIUM , COPPER , NICKEL , BRASS , MONEL , INCONEL SOFT STEEL , STAINLESS STEEL TYPES SS-304 SS-316 SS-321 SS-347 SS-410 SS-502ACCORDING TO CORROSIVE NATURE OF FLUID ENCOUNTERED
EXCHANGER GASKETS STANDARD SHAPES
DOUBLE JACKETED GASKETS
DOUBLE JACKETED CORRUGATED GASKET
TYPES OF JACKETED GASKETS
IT IS THE MOST COMMON USED STYLE USED IN HEAT EXCHANGERS APPLICATION ANY SHEET OF 26 GUAGE MAY BE USED ACCORDING TO SERVICE APPLICATIONS. THIS PARTICULAR TYPE CAN BE USED FOR MYRIAD OF APPLICATION.
PRIMARY AND SECONDARY SEALS IN DOUBLE JACKETED GASKETS ARE INNER AND OUTER LAPS OF GASKETS. THESE MUST BE UNDER COMPRESSION TO ACHIEVE SEALING. INTER MEDIAT PART DOES A VERY LITTLE JOB FOR SEALING CAPABILITIES. Double Jacketed Gaskets-Used on 300# AND 600# RATING HIGH TEMPERATURE APPLICATION OR WHERE CORROSIN PROBLEM MAY EXIST
Double-jacketed gaskets are probably the most
IN SOME CASES “ NUBBINS “ ARE PROVIDED ON HEAT EXCHANGERS DESIGN TO PROVIDE AN INTERMEDIAT SEAL. THIS NUBBINS IS NORMALLY 1/64” HIGH AND 1/8” IN WIDE. NUBBINS DESIGN PROVIDE BETTER SEALING OF ANY OTHER DOUBLE JACKETD GASKETS
NUBBIN
Double Jacketed Corrugated Gaskets- IT IS AN IMPROVEMENT ON A PLAIN JACKETED GASKET.CORRUGATION ON THE GASKETS WILL PROVIDE AN ADDITIONAL LABYRINTH SEAL RESULTING REDUCING THE CONTACT AREA AN ENHANCING ITS COMPRESSIVE CHARACTERISTICS.DOUBLE CORRUGATED JACKETED GASKETS PRIMARY SEAL STILL RELIES ON THE INNER LAP. LIGHTINGS ( CEMENT + LUBRICANT ) MAY BE USED WHICH WILL ASSIST IN FOLLOWING THE METAL FOR SEALING PURPOSE.
“ SPIRAL SEAL “ GASKETSARE MADE OF ALTERNATE PILES OF PERFOMED METAL AND SOFT NON METTALLIC FILLER . SPIRAL WOUND GASKETS HAVE BECOME EXTREMELY POPULAR DUE TOTHE WIDE VARIETY AVAILABLE STYLES AND SIZES.THE SPIRAL WOUND GASKETS MEETS THE MOST EXASTING CONDITION OF BOTH TEMPERATURE & PRESSURE.
THE SPW GASKETS COMPRISE A MIX OF METALLIC AND FILLER MATERIAL.THESE GASKETS CAN BE FABRICATED FROM ANY MATERIAL IN THIN STRIPS. AND CAN BE USED FOR ANY CORROSIVE MEDIUM DEPENDING UPON THE CHOICE OF METAL AND FILLER.
SPW GASKET CAN BE USED UPTO 2000 F TEMPERATURE AND ALL PRESSURE FROM VACCUM TO 2500 PSI. THE DENSITY OF GASKETS CAN BE CHANGED FOR VACUUM AND HIGH PRESSURE SERVICE
GENERALLY THE GASKETS HAS A METAL ( CARBON OR STAINLESS STEEL ) WOUND OUTWARD IN CIRCULAR
SPIRAL AND OTHER SHAPES ARE POSSIBLE & WITH THE FILLER MATERIAL ( GRAPHITE ) WOUND IN THE SAME MANNER BUT STARTING FROM THE OPPOSITE SIDE.
THIS RESULTS IN ALTERNATING LAYERS OF FILLER AND METAL. THE FILLER METAL IN THESE GASKETS ACTS AS THE SEALING ELEMENT , WITH THE METAL PROVIDING STRUCTURAL SUPPORT.
FILLER MATERIAL CAN BE CHANGED ACCORDING TO TEMPERATURE , PRESSURE, COMPRESSIVE FORCE
FILLER MATERIAL
ASBESTOS FILLER 1300 F
CERAMIC - 350 TO 2000 F
FLEXIBLE GRAPHITE - 350 TO 950
MICA GRAPHITE - 350 TO 550
SOLID TEFLON -32 TO 500 F
TEFLOM IMPREGNATED 600 F
GRAFOIL FOR HIGH TEMPERATURE
CENTRING RING MATERIAL
NORMALY CENTRING RING ARE MANUFACTURED BY CARBON STEEL AND ARE ZINC COATED FOR CORROSION PROTECTION. SS-304 , SS-316 , MONEL , INCONEL , TITANIUM
SPIRAL RING MATERIAL
LOW CARBON STEEL , MONEL , NICKLE , COPPER , INCONNEL , TITANIUMHASTELLOY , SS-304L , SS316L , SS-321 , SS-347, SS-410
SPIRAL WOUND GASKET SEALING METHOD
SPRING ACTION IS BUILT INTO EVERY SPW GASKETSPECIAL SPRING LIKE METAL STRIPS FORMED INTO “ V “ SHAPE ARE ALTERNATELY SPIRAL WOUND WITHSOFT FILLER BY A SPECIAL METHOD TO ASSURE FULL SUREFACE LEAK PROOF SEALTHE SOFT FILLER DOES THE SEALING AND “ V” SHAPE STRIPS PROVIDE THE SPRING ACTION. THIS COMBINATION OF THE FLOW OF METAL AND SOFT FILLERPILES COMPRESSES TO ITS PREDETERMINED THICKNESS UNDER BOLTING PRESSURETO SURFACE IRREGULARITIESAND PREVENT LEAKAGE WITHIN THE LIMITS OF ITS SPECIFIED TEMPERATURE AND PRESSURE RANGE.
VARIABLE DENSITY
SPW GASKETS ARE MANUFACTURED BYALTERNATELY WINDING STRIPS OF METAL AND SOFT FILLER OF TON OUTER EDGE OF WINDING MANDERALSTHAT DETERMINED THE DIMENTION OF WOUND COMPONENTDURING THE WINDING PROCESS ALTERNATE PILES ARE MAINTAINED UNDER PRESSURE. DENSITY OF THE GASKETS CAN BE CONTROLLED OVER A WIDE RANGE BY VARYING PRESSURE DURING WINDING OPERATION OR CHANGING THE THICKNESS OF SOFT FILLER.“ LOW WINDING PRESSURE AND THIK SOFT FILLER ARE USED FOR LOW PRESSURE APPLICATIONS.THIN FILLER AND HIGH PRESSURE LOADS ARE USED FOR HIGH PRESSURE APPLICATION. “HIGH DENSITY GASKETS WILL REQUIRE HIGHER BOLT LOAD TO FLOW THE MATERIAL INTO IMPERFECTIONS.
TYPES OF SPW GASKETS
GASKETS WITH THIS STYLE HAVE A METAL RING ON INNER SIDE OFSPIRALS . THICKNESS OF THIS METALLIC RING IS LESS THAN SPIRALS.INNER RING IS NORMALLY PROVIDED WITH SAME MATERIAL AS THE
SPIRAL WOUND COMPONENT BECAUSE IT WILL FACE THE SAME FLUID. GASKETS THICKNESS IS 3/16” NORMAL.
ADVANTAGES
• ADDITIONAL INNER RING SERVES TO STRENGTHEN THE SPIRAL SEALING ELEMENT• IT FILLS THE ANNULAR SPACE B/W FLANGE BORE AND
I.D OF PREVENT ACCUMULATION OF SOLIDS AND CORROSION
• BY FILLING ANNULAR SPACE IT REDUCES TURBULANCE IN . FLOW.
• THESE CAN BE USED FOR VACUUM SERVICES AND CAN
PROTECT THE PLANT IF GASKETS FAILS • THESE GASKETS ARE USED ON MALE AND FEMALE
FLANGES OR JOINTS PRIMARY REFORMER TUBES
SPW WITH INNER RING
THESE GASKETS HAVE A METAL RING ON THE OUTER OF SPIRAL. STANDARD GASKETS THICKNESS IS
3/16” AND ¼” OR 1/8” ARE ALSO AVAILABLETHICKNESS OF METAL RING IS LESS THAN
SPIRALS
ADVANTAGESMETAL RINGS PERFORM THE FOLLOWING IMPORTANT FUNCTIONS
• CENTERS THE GASKETS IN THE JOINT.• PROVIDE EXTRA RADIAL STRENGTH TO PREVENT GASKET BLOW OUT• RESISTS THE ATMOSPHERIC CONDITION.• HELPS TO PREVENT OVER COMPRESSION OF THE SEALING ELEMENT AND ACTS AS COMPRESSION GUAGE • IT IS USED IN FLAT FACE AND RAISE FACE FLANGES PROCESS LINES FLANGES , STEAM LINES FLANGES , MANHOLES OF VESSELS.
THESE GASKETS HAVE METAL RING ON INSIDE & OUTSIDE OF THE SPIRALSWITH THICKNESS LESS THAN SPIRALS. IT HAS THE COMBINED ADVANTAGES
OF SPW GASKETS WITH INNER RING AND SPW WITH OUTER RING IT PROVIDES A BARRIER OF HEAT AND CORROSION AND PREVENT
FLANGE FACE FOR CORROSION.IT GIVES ADDITIONAL COMPRESSION STOPSTANDARD GASKETS THICKNESS IS 3/16” AND ¼” AND 1/8” ARE ALSO AVAILABLE
• THESE GASKETS NORMALY USED FOR FLAT FACE AND RAISED FACE FLANGES HIGH TEMPERATURE & HIGH PRESSURE SERVICES TOXIC AND CORROSIVE MEDIA
THESE GASKETS ARE COPOSED OF SPIRALS WINDINGS ONLY , WITHOUTINNER AND OUTER METAL CENTERING RINGS.INNER AND OUTER OF THE
GASKETS ARE REINFORCED WITH SEVERAL PILES OF METAL WITHOUT FILLERTO GIVE GREATER STABILITY BETTER COMPRESSION AND SEALING CHARACTERISTICS. THESE ARE AVAILABLE IN DIFFERENT STYLES
ITS THICKNESS IS 3/16” ¼” AND 1/8”
THESE GASKETS ARE NORMALY USED IN TONGUE & GROOVE , MALE & FEMALE , GROOVE TO FLAT FLANGE
FACES JOINTSVALVE BONNETS MANHOLE COVERS PROCESS LINES
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