Blind Plate Thk - Hydro.pdf

DOC.No:PE-C781-MDC-002-02

DESIGN CALCULATIONS FOR BLIND FLANGE

TABL E OF CONTENTS Sl . No .

Description

Pag e No .

Table of Contents

1

Design Data

2

1.0

Bottom Plate

2

2.0

Blind Flange Stiffener

3

2.1

Vertical Stiffeners on Blind Flange

3

2.2

Horizontal Stiffeners on Blind Flange

3

2

8-Feb-2018

REV

DATE

BLIND FLANGE CALCULATION

Rev No

NKJ

SM

SM

PREPARED BY

CHECKED BY

APPROVED BY

DESIGN DATA Design Code

:

Good Engineering Practice

Blind Flange with Pipe Spool

:

(Roarks& Young Formulae, 7th Ed. And Dennis Moss Hand book) Hydrotest Fab. Flange

OD of Spool (mm)

:

Provided Thk. (mm)

:

Test Pressure

:

2110

2110

20 6.21 bar g 6.33 Kg/cm²

Des pr+Static Head

 Additional liquid column for design consideration, H1

:

2110

mm

Design Temp. (Min/Max)

:

(Amb / 38)

°C

Material

:

SA-36

Corrosion Allowance

c

:

0  mm

Modulus of Elasticity- E (at 65°C) : As per Table TM-1 of Sec II Part D Design density of Liquid  Actual density of liquid

2049637.2 Kg/cm² 3

ε

1000 Kg/m

ε1

1000 Kg/m3

Yield Strength of SA 36 @ Design Temperature Sy

2549.3 Kg/cm2

 Allowable Stress = S = 0.667* Yield Stress 1.0 Bottom Plate Reference for Calculation

1700.3831 Kg/cm2

Formulas for Stress and Strain by Roark & Young - Page No.508 :

Table 11.4, Case No: 8a - Uniform over entire plate Blind Fabricated Weight = W= a = Length of unsupported long side =

500 Kg. 500 mm

(Conservative) (maximum as per drawing)

b = Length of short side = 500 mm a/b = 1.000 Pressure due to additional liquid q1 = H1*0.1*1 = 0.211 Kg/Sq.cm. q = Load per unit area ( considering fully filled with liquid +fabricated material wt. of tank ) ((L*B*H*ε)+ W)/(L*B) + q1 = = 0.22 Kg/Sq.cm. From Table11.4-8a, ß = 0.3078  Alpha = 0.0138 Max. Bending Stress (σ) = ß*q*b²/(t² ) = 1217.6029 Kg/cm² Minimum Reqd Thickness t(min)= Sqrt(ß*q*b²/(S)+c= Provided Thickness of plate t1mm = 20 mm Max. Bending Stress < Allow able stress So selected plate thickness can be used 4 3 Max. deflection = y = Alpha*q*b /(E*t ) = 0.0012 cm  Allowable Deflection = 1/200 * Total maximum unsupported length = Deflection is with in Allowable limits

16.924 mm {t= (t1-c) =

2 cm} 0.012 mm 2.5 mm

>y

2.0 Blind Flange Stiffener(500mm) (Case No:1a Page No.502 Roark's & Young Formula ) Considering 2 nos Vertical stiffeners kept at a equal maximum spacing of 308mm q = Max. Load per unit area ( considering fully filled with water ) q = 6.33 Kg/cm² (due to static head at the bottom) a= 50 cm ; b= a/b =

50 cm ;

ß=

0.2874

1.000

Thickness considered for side plate t1 (mm) = Minimum Reqd Thickness t(min)= -Sqrt(ß*q*b²/(S)+c= Stress induced at bottom of section σ b =

 Alpha = { t =(t1-c)=

20

0.0444 2 cm

16.354 mm ß*q*b²/(t²)

1136.90 Kg / cm2

Max. Bending Stress < Allow able stress So selected plate thickness can be used 4 3 Max. deflection = y = -Alpha*q*b /(E*t ) = 0.107 cm =  Allowable Deflection = 1/200 * Total maximum unsupported length = Deflection is with in All owable limits

1.0712 mm. 2.50 mm

<0.66Ys, Safe

>y

2.1 Vertical Sti ffeners on Bli nd Flange (Ref. Denni s Moss Page No. 231) Stiffener Size = 20mm (Thk) X 100mm (Width) Length of stiffener a = 500 Bending Moment on the stiffener M = 0.0642qla^2 Stiffener used : 20mm (Thk) X 100mm (Width)

500 mm mm = having

50792.79 Kg-cm

Moment of Inertia Iyy Section Modulus Zyy=

166.67 cm4 33.33 cm3 3 29.871 cm

Required Section Modulus(Zreqd.) = M/S = Stress induced in Stiffener= M / Zxx = 1523.936 Kg/ cm2 Max. Bending Stress < Allow able stress So selected plate thickness can be used 4 Max. deflection = y =2.5q*la /384EI = 0.0377 cm  Allowable Deflection = 1/200 * Total maximum unsupported length = Deflection is within Allowable limits

0.377 mm 2.50 mm

2.2 Horizontal Stiffeners on Blind Flange (Ref. Dennis Moss Page No. 231) q = 6.3293 Kg/cm² (due to static head at Bottom Stiffener ) Stiffener Size = 20mm (Thk) X 100mm (Width) 500 mm Length of stiffener b = 500 mm Bending Moment on the stiffener M = qlb^2/8 = 98895.63 Kg-cm Stiffener used : 20mm (Thk) X 100mm (Width) having Moment of Inertia Ixx= Section Modulus Zxx= Required Section Modulus(Zreqd.) = M/S = Stress induced in Stiffener= M / Zxx = 2967.165 Kg/ cm2 Not Safe Max. Bending Stress > Allowable stress So go for hig her thickness 4 Max. deflection = y =5q*la /384EI = 0.0754 cm 0.754 mm  Allowable Deflection = 1/200 * Total maximum unsupported length = 2.50 mm Deflection is within Allowable limits

>y

166.67 cm4 33.33 cm3 3 58.161 cm

>y