Accumulator Saddle DesignMetric British

Parameter Symbol Unit Value UnitDesign Pressure (Internal) P kg/mm2 0.1

Design Pressure (External) kg/mm2 0.0

Shell ID mm 2000 ft

Shell mean radius mm 1014Shell Straight Length L mm 10000 ftDish End Type Semiellipsoidal (2:1)Material SA 516 Gr 70Allowable stress S kg/mm2 14.1

Minimum Yield stress kg/mm2 26.5Dish End Length H mm 567.4 ft

Dish End thcikness mm 12.0 inch

Dish End OD mm 2024 inchStraight Face SF mm 50.0 inchKnuckle Radius Kr mm 344.1 inch

Shell thickness mm 14.0 inchCalculation of maximum operating weight

Dish End Blank Dia mm 2402 inchDish End Weight kg 435 lbShell Weight kg 7086 lbEmpty vessel weight kg 7956 lbDish end volume m3 1.2 ft3Shell volume m3 31.4 ft3Total vessel volume m3 33.8 ft3

Hydrostatic wt of vessel kg 41781 lb

Consider saddle dimensions as highlighted in the saddle tableSaddle angle Deg 120A/L ratio to be considered A/L 0.2Shell Overhang beyond saddle A mm 2000 ft

Distance between saddles mm 6000 ftDimension B (CL Height from base) B mm 1295 inchBase Plate Width F mm 203 inchSaddle width b mm 178 inch

Wear Plate thickness mm 14Wear Plate Width mm 370

Stiffener ring cross section area mm2 4340

Stiffener ring moment of inertia mm4 8107447 Seismic Load EstimationHorizontal seismic factor Ch (Procedure 3-3)Importance factor I 1.0

Pe

Di

Rm

Fy

th

Do dish

ts

Dblank

Wo

Ls

tw

Ar

I1

Coefficent (max value from Table 3-9a) 0.36

Coefficent (max value from Table 3-9b) 0.84

Coefficiecnt for self supported 2.9Period of Vibration T NAShear Load 1 V1 kg 8423 lbShear Load 2 V2 kg NAShear Load 3 V3 kg 12966Max shear load V kg 6016

Horizontal Seismic factor 0.14

Seimic Load (longitudinal) kg 6016

Seimic Load (transverse) kg 3008

Wind Load EstimationHorizontal seismic factor Ch (Procedure 3-3)

Shell ID mm 2000 inchEffective diameter factor from table 3-22 1.3

mm 2560 ft

Area 5.1

Factor 0.80Factor G 0.85

Factor from Table 3-23 0.85Factor I 1.15Basic wind speed from IS 875 V m/s 47 mph

velocity pressure 135.2 psf

Area Af m2 28.5 ft2

wind Load (Longitudinal) kg 473 lb

wind Load (transverse) kg 1310 lb

Maximum Londitudinal load kg 6016 lb

Maximum Transverse load kg 3008 lb

Longitudinal Q1 kg 22189 lb

Transverse Q2 kg 22839 lbTotal saddle reaction force Q kg 22839 lb

Longiudinal Bending

Moment at Saddle kg m 131521 lb ftFactor k1 from Table k1 0.335

Bending stress in tension w/o stiffener 27.7Factor k7 from Table k7 0.603

Bending stress compression w/o stiffener -15.4

Ca

Cv

Rw

Ch

FL

Ft

Di

De

Ai m2 ft2

Cf

Kz

qz kg/m2

Af

FL

Ft

FL

Ft

Q1

Q2

M1

S1 kg/mm2

S2 kg/mm2

Bending stress with stiffener 3.0

Moment at midspan kg m 97789

Bending stress at midspan 2.2Tangential Shear

Tangential shear (Stiffened shell) 0.3Factor k2 from Table k2 1.171

Tangential shear ( shell not stiffened) 1.1Factor k3 from Table k3 0.880

Tangential shear ( shell not stiffened) NA

Tangential shear ( shell not stiffened) 0.0Circumferential BendingA/R ratio 2.0

k6 0.053

At saddle horn (shell not stiffened) -10.4

At saddle horn (shell not stiffened) NAAdditional Tension Stress in HeadFactor k4 from Table k4 0.401

Stress 0.0Circumferential Tension / CompressionFactor k5 from Table k5 0.760

Circumferential Compression -2.8Factor k8 from Table k8 0.340Factor k9 from Table k9 0.053

Circ Stress in shell with stiffener -10.9

Compressive stress in stiffener -10.9Pressure Stresses

3.8

7.6

0.4

4.7

7.6Combined Stress Table

Tension CompressionFormula Value Result Formula Value Result

Actual Allowed Actual Allowed

31.5 14.1 Unsafe 15.0 14.1 Unsafe

6.8 14.1 Safe -3.3 14.1 Safe

6.0 14.1 Safe -2.6 14.1 Safe

7.6 17.6 Safe 10.5 13.3 Safe

S3 kg/mm2

M2

S4 kg/mm2

S5 kg/mm2

S6 kg/mm2

S7 kg/mm2

S8 kg/mm2

Factor k6 from graph for A/R and S9 kg/mm2

S10 kg/mm2

S11 kg/mm2

S12 kg/mm2

S13 kg/mm2

S14 kg/mm2

x kg/mm2

kg/mm2

e kg/mm2

s kg/mm2

h kg/mm2

S1 + x -S2 - e

S3 + x -S3 - e

S4 + x -S4 - e

S11 + h -S13 - e

-3.2 21.1 Safe 10.5 23.9 SafeS13 + -S14 - e

Value

6.6

32.8Shell Stiffener Dimensions

1 No at each saddle all round the shell

1.9 14

0.5

79.72.0 120

13.5

0.6 14190

94.6957

155901750442.5

1108.61193.6

91917

0.26.6

19.75187

0.6

1

0.36

0.84

18531

13236

0.144

13236

6618

78.71.28

8.4

55.4

0.800.85

0.851.15105

27.6

306.7

1041

2883

13236

6618

48816

5024550245

949301

Confirms stiffeners are required.

For plate thickness less than 25 mm / 1.0 inch

Blank Diameter = D + (D/42) + (2*S.F)+ ((2/3) * Kr)

For plate thickness equal or more than 25 mm / 1.0 inchBlank Diameter = D + (D/42) + (2*S.F) + ((2/3) * Kr)+ thk

where,D = Outside Diameter of Ellipsoidal Head

Kr = 0.17*D = Knuckle Radiusthk = Thickness of Head

S.F. = Straight Face 

Ellipsoidal Head Volume = (π * D³ )/ 24 + (π* D² * S.F )/ 4

where,

π = 3.141D = Inside Diameter of Ellipsoidal HeadS.F. = Straight Face

HEAD VOLUME