design bolt torque for sealing flanges
DESCRIPTION
DesignTRANSCRIPT
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BOLT TORQUE REQUIRED FOR SEALING FLANGESRef: Procedure No. 2-10 pg. no. 59, Pressure Vessel Design Manual by Dennis Moss, 3rd edition.DESIGN DATAFlange size=30" ID x Class 600 LWNRTJDesign pressureP=46.6kg/cm2=46.6 x 9.80665 / 100=4.57N/mm2Test pressurePT=60.827kg/cm2=60.827 x 9.80665 / 100=5.965N/mm2MomentM=166.594kN-m=166.594 x 1000 x 1000=166594000N-mmRadial loadPr=152.2kN=152.2 x 1000=152200NFriction factorK=0.3Design temperature=295C
GASKET DATA
TypeOctagonal Ring R-95 (5Cr-1/2 Mo)Width of ring joint gasketw=19.05mm(As per B 16.20)Gasket factorm=6(As per ASME Sec VIII Div 1 Table 2-5.1)Gasket unit seating loady=150N/mm2(As per ASME Sec VIII Div 1 Table 2-5.1)Modulus of elasticity of gasketEg=195300N/mm2material at temperature(As per Sec. II Part D Table TM-1)Thickness of gaskettg=8.045mmDiameter at location of gasket loadG=857.25mmreaction (As per B 16.20)
BOLTING DATAMaterial=SA-193 B16 (1Cr-1/2Mo-V)Nominal size=2" UN8Quantityn=28Root diameter of threadsd=1.8466in(As per B 18.2)=1.8466 x 25.4=46.904mm
Pitch diameter of threadsdm=1.9188in(As per B 18.2)=1.9188 x 25.4=48.738mmModulus of elasticity of boltingEb=186400N/mm2material at temperature(As per Sec. II Part D Table TM-1)Cross-sectional area of boltsAb=
=( x 46.904 ^ 2 x 28 ) / 4=48380.202mm2Thickness of nuttn=1.9688in(As per B 18.2)=1.9688 x 25.4=50.008mm
Dimension (refer above figure)x=285.56mmEffective length of bolt, mid nut tolb=mid nut=285.56 + 50.008=335.568mmEquivalent PressurePe=
=( 16 x 166594000 ) / ( x 857.25 ^ 3 ) + ( 4 x 152200 ) / ( x 857.25 ^ 2 ) + 4.57=6.181N/mm2Hydrostatic end forceH=
=( x 857.25 ^ 2 x 6.181 ) / 4 3567496.967NTotal joint-contact-surface compressionHp=load=2 x 19.05 x x 857.25 x 6 x 6.181=3805330.098NMinimum required bold load for gasketWm2=seating=7695619.83879325NActual joint are contact for gasketAg==2 x x 19.05 x 857.25=102608.265mm2
Decreasing compression force in gasketF=
=3567496.967 / ( 1 + ( 48380.202 x 186400 x 8.045 ) / ( 102608.265 x 195300 x 335.568 ) )=3529418.655NInitial required tightening forceFbo=(tension)=3805330.098 + 3529418.655=7334748.753NTotal tightening force required to sealW=joint=Max ( 7334748.753 , 7695619.839 )=7695619.839N=7695619.839 / 1000=7695.62kNRequired torqueT=
=4018597.711N-mm=4018597.711 / ( 1000 x 1000 ) =4.019kN-m
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