blind flange design calculations - by abdel halim galala

DESIGN CALCULATIONS OF HEAT EXCHANGER Page : 76 of 136

According to ASME Code, Sec. VIII, Div. 1, Edition 2001, Addenda 2002 / TEMA "R" 7th Edition 88. Sheet : 1 of 6

Designed by : Eng. Abdel Halim Galala, Design General Manager (Assistant) Rev. : 0

Project : Design & Fabrication of Heat Exchanger for APRC Refinery Date : 4.7.2003

Job No. : 7443-33 Location : Alex.

Dwg. No. : 7443-33-1A, Rev. 0 Sheet : 14 Client : APRC

Exchanger : Residue Cooler, Type : AES, TEMA class : R Item : E-323A/B & E-514C/D

P. Flat Unstayed Circular Blind Flange(Channel Cover) Thickness (item no. 22) [UG-34 & Fig. UG-34 Sketch (j)]

[Attached by Bolts] Subjected to internal pressure

Blind Cover Material, Clad Metal : SB171 UNS No. C63000 ASME SA266 Class 2

Stud bolt material SA 193 Grade B7

Design Temperature 140oF 60

oC

Min. Design Metal Temperature, MDMT 53.6oF 12

oC

Bolt-up and Gasket Seating Temperature 86oF 30

oC

Assume corrosion allowance, C [UG-25] 0.19685 INCH 5 MM

Operating Pressure (tube side) 56.8182 PSIG 4 Kg/CM2G

Internal Design Pressure, P (MAWP) 71.7082 PSIG 5.04826 Kg/CM2G

Allowable Stress of Bolt Material, SB :

* at design temp.(operating condition), Sb 25000 PSIG 1760 Kg/CM2G

* or at atmospheric temp./bolt-up temp. (gasket seating), Sa 25000 PSIG 1760 Kg/CM2G

Allowable Stress of Flange Material :

* at design temp.(operating condition), SfH 20000 PSIG 1408 Kg/CM2G

* or at atmospheric temp./bolt-up temp. (gasket seating), SfC 20000 PSIG 1408 Kg/CM2G

[Table 1A , SubPart 1 , ASME Sec. II , Part D]

Joint efficiency, E 1

Bolt Hole, 1.10236 INCH 28 MM

Flange outside diameter, A 26.9685 INCH 685 MM

Bolt circut diameter (B.C.D.), 24.5276 INCH 623 MM

Fig. UG-34, Sketch (j)

Figure (5)

No. of bolts 28

Nominal bolt dia., dB 1 INCH 25.4 MM

Actual cross-sectional area of each bolt, [TEMA Table D-5] 0.551 INCH2 355.4832 MM

2

Total actual cross-sectional area of bolts, Ab 15.428 INCH2 9953.528 MM

2

Flange face outer diameter 22.1654 INCH 563 MM

Flange face inner diameter 19 INCH 482.6 MM








P. Flat Unstayed Circular Blind Flange (Channel Cover) Thickness (item no. 22) (cont.)

[Attached by Bolts] [UG-34 & Fig. UG-34 Sketch (j)]

Gasket Details: - Flat metal, jacketed asbestos filled, soft copp[er or brass 0.125 INCH 3.175 MM

- Outside diameter 22.0472 INCH 560 MM

- Inside diameter = O.D - 2N 20.8661 INCH 530 MM

- Width, N 0.59055 INCH 15 MM

Gasket Dimensions:

Basic gasket seating width, bO = N/2 [Table 2-5.2] 0.29528 INCH 7.5 MM

Since bo > 1/4 ", Effective gasket seating width, b = 0.5 SQRT(bO) [Table 0.2717 INCH 6.901087 MM

Gasket Factor, m [Table 2-5.1] 3.5

Min. Seating Stress, y [Table 2-5.1] 6500 PSIG 457.6 Kg/CM2G

Facing Sketch [Table 2-5.1] (1a); Column II

Diameter at location of gasket load reaction, d ( d represnts G )

When bo is larger than 1/4", d = O.D.of gasket contact face - 2 b 21.5039 INCH 546.1978 MM

[Appendix 2-3]

Factor depending upon method of attachment of head, C [Fig. UG-34, Sketch (j)] 0.3

Gasket moment arm, hG = (B.C.D - d)/2 = (C-G)/2 [Table 2-5.2] 1.51185 INCH 38.40109 MM

Calculating the Min. required Thickness of Blind Flange, t:

[UG-34(c)(2)]

When using this formula, the thickness t shall be calculated for

both operating conditions, and gasket seating, and the greater

of the two values shall be used.

SA 193 Grade B7oF 100 140 150

PSI 25000 ? 25000

ASME SA266 Class 2oF 100 140 200

PSI 20000 ? 20000

3G/SEd1.9Wh+ CP/SEd = t










Calculating the total bolt load, W (for circular heads):

1. For operating conditions, the value of P shall be the design

pressure, and the value of S at the design temperature and W

from Formula (3) of 2-5(e) shall be used.

Flange Design Bolt Load for circular heads, W [Appendix 2-5(e)]

For operating conditions, W = Wm1 (3)

Wm1 = H + Hp = 0.785 G2P + (2b x 3.14 GmP) (1) [Appendix 2-5(e35243.2 lb 15986.05 Kg

Flange thickness 0.85602 INCH 21.74301 MM

2. For gasket seating, P equals zero, and the values of S at

atmospheric and W from Formula (4) of 2-5(e) shall be used.

[UG-34(c)(2)]

P 0 PSIG 0 Kg/CM2G

S 20000 PSIG 1408 Kg/CM2G

Flange Design Bolt Load for circular heads, W [Appendix 2-5(e)]

For gasket seating, W = 0.5(Am + Ab) Sa (4)

Total required cross-sectional area of bolts, Am = Max (Am1,Am2)

Required bolt load under atmospheric temp.conditions, Wm2 = 3.14bGy (2) 119246 lb 54089.04 Kg

* Total cross-sectional area of bolts at root of thread requiired

at operating conditions , Am1 = Wm1/ Sb 1.40973 INCH2 909.4991 MM

2

* Total cross-sectional area of bolts at root of thread required

gasket seating, Am2 = Wm2/ Sa 4.76983 INCH2 3077.304 MM

2

Total required cross-sectional area of bolts, Am = Max (Am1,Am2) 4.76983 INCH2 3077.304 MM

2

For gasket seating, W = 0.5(Am + Ab) Sa (4) 252473 lb 114519.9 Kg

1.29857 INCH 32.98372 MM

t = max. of t of operating and gasket seating 1.29857 INCH 32.98372 MM

Use t without corrosion allowance 1.29921 INCH 33 MM

Use t for construction including R.F. 2.00787 INCH 51 MM

N.B. Check which the deflection is considered a governing thickness or not. 2.48031 INCH 63 MM

The deflection is ehe governing thickness

t = d CP / SE +1.9Wh / SEd^G 3

t = d CP / SE + 1.9Wh / SEd^G 3










CONCLUSION:FLANGE SUMMARY

Flange thickness (without C.A.) 1.29857 INCH 32.98372 MM

Use t for construction including R.F. 2.04724 INCH 52 MM

For a proper design of flange :

1. You have to make a check for flange deflection.

GASKET SUMMARY

Gasket width, N 0.59055 INCH 15 MM

Required cross-sectional of bolts, Am 4.76983 INCH2 3077.304 MM

2

Actual cross-sectional area of bolts, Ab 15.428 INCH2 9953.528 MM

2

BOLT SUMMARY

No. of bolts 28 Bolt

Size of bolt (the bolt size is represented by its actual cross-sectional area) 1 INCH 25.4 MM

Bolt hole dia. 1.125 INCH 28.575 MM

Total required cross-sectional area of bolts, Am 4.76983 INCH2 3077.304 MM

2

Total actual cross-sectional area of bolts, Ab 15.428 INCH2 9953.528 MM

2

Actual cross-sectional area of bolt, [TEMA TABLE D-5] 0.551 INCH2 355.4832 MM

2

Since the actual bolt area Ab > The required bolt area Am,

the bolts are adequately enough.

N.B. When using bolt with size 0.75 INCH NA

Total required cross-sectional area of bolts, Am 4.76983 INCH2

Total ctual cross-sectional area of bolts, Ab 8.456 INCH2

Actual cross-sectional area of bolt, [TEMA TABLE D-5] 0.302 INCH2

Since the actual bolt area Ab < The required bolt area Am,

the bolts are inadequately enough.

Edge distance, E from drawing = 1/2 (A - C) 1.22047 INCH 31 MM

Min. Edge distance, E (for bolt size 0.75") 0.8125 INCH 20.6375 MM

Min. Edge distance, E (for bolt size 1") 1.0625 INCH 26.9875 MM

Min. edge distance, E (for bolt size 1-1/8") [TEMA Table D-5] 1.125 INCH 28.575 MM

Min. Edge distance, E (for bolt size 1.25") 1.25 INCH 31.75 MM










Actual Bolt spacing, B (c/c) from drawing 2.74622 INCH 69.75387 MM

Min. Bolt spacing, B (for bolt size 0.75") 1.75 INCH 44.45 MM

Min. Bolt spacing, B (for bolt size 7/8") [TEMA Table D-5] 2.0625 INCH 52.3875 MM

Min. Bolt spacing, B (for bolt size 1") 2.25 INCH 57.15 MM

Min. Bolt spacing, B (for bolt size 1-1/8") 2.5 INCH 63.5 MM

Min. Bolt spacing, B (for bolt size 1-1/4") 2.8125 INCH 71.4375 MM

Max. Recommended bolt spacing, Bmax = 2 dB + 6 t / (m + 0.5) [TEMA RCB3.94882 INCH 100.3 MM

Check for Flat Channel Cover Deflection [TEMA RCB-9.21]

The effective thickness of a flat channel cover shall be the thickness at the

bottom of the pass partition groove (or the face if there is no groove) minus

corrosion allowance in excess of groove depth. The thickness is to be at

least that required by the appropriate Code formula and thicker if required

to meet proper deflection criteria.

The recommended limit for channel cover deflection is:

0.03" for nominal diameters thru 24" 0.03 INCH 0.762 MM

0.125% of nominal diameters (nominal diameter/800) for larger sizes 0.025 INCH 0.635 MM

Nominal diameter = Shell ID + 2 ts 20 INCH 508 MM

A method for calculating of channel cover deflection at the center, Y is:

Where G = Gasket load reaction diameter as defined by the Code 21.5039 INCH 546.1978 MM

E = Modulus of elasticity at design temperature [ASME Sec.II,Part D, TM-31460000 PSI 2214784.07 Kg/CM2G

T = Thickness under consideration (minus groove and C.A.) 1.29921 INCH 33 MM

P = Design pressure 71.7082 PSIG 5.04826 Kg/CM2G

SB = Allowable bolting stress at design temperature (Wm1) 25000 PSIG 25000 Kg/CM2G

AB =Actual total cross-sectional root area of bolts 15.428 INCH2

9953.528 MM2

hG = Radial distance from diameter G to bolt circle 1.51185 INCH 38.40109 MM

If the calculated deflection is greater than the recommended limit,

the deflection may be reduced by acceptance methods such as:

(a) Increase channel cover thickness by the cube root of the

ratio of calculated deflection to the recommended limit.

(b) Use of strong backs.

(c) Change type of construction.

Note: For single pass channels, or others in which there is no pass partition

gasket seal against the channel cover, no deflection criteria need be

considered.

( )GBB

33

hAS5.0+PG0435.0TE

G=Y










The calculated deflection is 0.10054 INCH 2.553795 MM

The recommended deflection limit 0.03 INCH 0.762 MM

Since the calculated deflection exceeds the recommended deflection, we have

to increase the flange tickness by the cubic root of the ratio of deflections,

[TEMA RCB-9.21] 2.88948 INCH 73.39285 MM

0.00914 INCH 0.232149 MM

Easier approach :

1. Assume T, 1.88283 INCH 47.824 MM

2. Find Calculated deflection 0.03303 INCH 0.839054 MM

3. Recommended deflection limit 0.03 INCH 0.762 MM

4. Compare the calculated deflection with the recommended deflection OK

The minimum thickness of channel cover at bottom of pass partition is 1.88283 INCH 47.824 MM

The thickness neglecting corrosion allowance is 1.88976 INCH 48 MM

Conclusion : Checking of Deflection

The min. thickness of channel cover to resist the internal pressure is 1.33858 INCH 34 MM

Where the min. thickness of channel cover to avoid deflection is 1.88976 INCH 48 MM

The min. thickness of channel cover as derived from drawings is 1.9685 INCH 50 MM

The flange thickness increased by 0.07874 INCH 2 MM

Tthickness including groove depth ( 5 MM) 2.08661 INCH 53 MM

Overall thickness including raised faces & groove depth 2.48031 INCH 63 MM

Max. Working Pressure, MWP at New (cold) & Operating (corroded)

at New (cold) P = SE t2 /d

2 c - 1.9 W hG / d

3 c 104.094 PSIG 7.328196 Kg/CM

2G

at Operating (corroded) P = SE t2 /d

2 c - 1.9 W hG / d

3 c 104.094 PSIG 7.328196 Kg/CM

2G

( )YG

E TG P S A h

B B G= +

3

30 0435 0 5. .

T TY

Yassumed

calculated

recommended

= + 3

( )YG

E TG P S A h

B B G= +

3

30 0435 0 5. .

( )YG

E TG P S A h

B B G= +

3

30 0435 0 5. .

blind flange design calculations - by abdel halim galala

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