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JAKHAPUPR L. I .S

ECONOMICAL DIAMETER FOR RISING MAIN

DATA

1 Total discharge in cum/sec = 0.64

2 No of rows of rising main No. = 1

3 Length of rising main in m. = 1300

4 Static head for pump in m (HSP 66.50F.S.L. IN DC = 721.3

5 Hf. IN pump assembly = 0.67POL. = 654.80

(1% of Hsp)

6 static head for rising main (HSR 26.3C.L of rising main = 695

7 No of pumps = 2

8 Discharge per pump in cum/sec 0.319Cr = Roughnes coefficient of pipe = 1

9 Pump efficiency = 0.9

Head for rising main Pipe shell thickness mm

1 2 3 4 5 6 7 8 9 10 11 12 13 14

1 0.55 1 0.64 2.00 2.68 26.3 10.25 11.27 150.34 187.92 3.31 3.10 2.95 8

2 0.60 1 0.64 2.00 2.25 26.3 6.74 7.42 129.71 163.43 3.15 3.38 3.09 10

3 0.65 1 0.64 2.00 1.92 26.3 4.59 5.05 108.85 140.20 2.92 3.66 3.23 10

4 0.70 1 0.64 2.00 1.66 26.3 3.21 3.53 92.48 122.31 2.74 3.94 3.38 10

5 0.75 1 0.64 2.00 1.44 26.3 2.31 2.54 79.41 108.24 2.60 4.23 3.52 10

Sr.No.

Dia.ofrisingmain

No.ofrows

Dischargeper row

No.ofpumps

Velocityin m/sec

Statichead in

m.

Frictionhead Hf

in m.

Totalfrictionhead =

1.1*Hf m.

50% ofwater

hammerhed in m.

Design head=

col.7+9+10

T1 forinternalpositivepressure

as per I.S.5822-1994

T2 forexternalnegativepressureas per

I.S.5822-1994

T3 forhandlingpoint ofview asper I.S.4480

(part-7)-1975

(Cl.5.1.1)

T4minim

as petable -3I.S. 35

199

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CALCULATIONS FOR H.P

The speiman calculations for optimization study

Data

1 Total discharge = Q cum/sec 0.64

2 No. of working pumps = No. 2

3 Discharge per pump = q cum/sec 0.3194 Total No. of rising main = No. 1

5 Discharge of rising main per row = Q1 cum/sec 0.64

6 Diameter of rising main = D m 0.65

cm 65

mm 650

7 length of rising main = L m 1300

8 Velocity through rising main = V m/sec 1.920

< 2.1 m/sec

Permissible velocity

9 Details of source.

9.1 M.D.D.L. m 653.0189.2 F.S.L. m 655.668

9.3 H.F.L. FRL m 655.67

9.4 P.O.L. POL m 654.790

9.5 F.S.L. in delivery chamber FSLD m 721.300

9.6 Centre line of celivery pipe CLD m 695.000

9.6 thiclness of rising main t mm 6

cm 0.6

m 0.01

Calculations

a) Static head for rising main = HSR

FSLD - CLD = m 26.300

b) Static head for pumping = HSP

FSLD - POL = m 66.510

c) Frictional head loss ithe rising main by Modified Hazen William's formula

Hf = ((L*(Q1/Cr)^1.81)/(994.62*D^4.81)

Where

L = Length of rising main = m 1300

Q = Discharge of R.M./row = cum/sec 0.64

Cr = Roughness coefficient = 1

( as per Water Supply Manual & Treatment)

D = Diameter of rising main = m 0.65

Now Hf = m 4.5884

Assume losses in bends,elbows,tee etc

10% of Hf m 0.459

Total head loss in R.M. Hft = m 5.047

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d) Water Hammer pressure in the rising main.

Maximum water hammer pressure

WHP =C*(Vo/g)

Where

C = wave velocity

g = gravitional acceleration m/sq sec 9.81

Vo = velocity in rising main m/sec 1.920

C = 1425/sqrt(1+K*(D/t))

Modulus of Elasticity of pipe material

Bulk Moeulus Of Elasticity of water = Kg/sqcm ###

Modulus of Elasticity of pipe material Kg/sqcm ###

K = 0.01

D = m 0.65

t = m 0.01

C = m/sec 990.96

WHP = m 193.91

For design purpose 50% of WHP is considered

Design WHP = m 96.957

e) Design pressure head

e-1) Working pressure head = Wp

HSR +Hft = m 31.347

e-2) Design pressure head = Wd =

Wp + Design WHP = m 128.304

Kg/secm 12.830

f) Thickness of rising main.

f-1) T1 thickness for internal positive pressure as per I.S.-5822-1994

T1 =((P*D/((2*a*f*e)+p))*1.125*10 mm

WhereP = Design pressure = Kg/sqcm 12.830

D = Outer Dia. Of pipe = cm 66.2

a = design factor = 0.9

when surge pressure is considered

f = Specified yield stress= Kg/sqcm 2500

(from I.S.-2062-1992 table-2)

e = weld efficiency = 0.8

(for field welding)

mm 2.645

K = Bulk Moeulus Of Elasticity of water

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Now T1 =

f-2) T2 thickness for -ve (vaccume) pressure as per I.S.- 5822-1994

clause B-3.1

(1-y^2)

Where

pcr = vaccume pressure = 1/3 of atmospheric pressure +Over brden of 1.2m

vaccume pressure = Kg/sqcm 0.33

Over burden Wt of soil = 1.2*0.208 Kg/sqcm 0.25

(0.208 = saturated wt. of soilin kg/sqcm)

total pcr= 0.58

E Young's modulus of pipe material = Kg/sqcm 2100000

Y = Poission's ratio = 0.3

D = internal Dia = cm 65

Now T2 = mm 3.663

f-3) Thickness from handling point of view as per I.S.-4880-(part-7)-1975

Clause 5.1.1

t = ((D+50)/400)*10*1.125

Where

D = diameter of pipe in cm = cm 65

Now T3= mm 3.234

f-4) Minimum thickness as per I.S.-3589-1991

(As per table 3)

T4 = mm 6

Maximum of T1, T2, T3, T4 = mm 6

Consider corrosion allowance mm 0

(as Dia. Of rising main is less than 1000)

Thickness provided = mm 6

However provide the thickness mm 10

h) pumping capacity

Hp required =( w*Q*H)/75*)Where

w = unit wt of water = Kg/cum 1000

Q = total discharge = cum/sec 0.64

H = total head =

HSP + pump assembly losses + Hft

Pump assembly losses = 1% of static head

for pumping = m 0.67

H = total head = m 72.222

= Pump efficiency = 0.9

pcr = (2*E*(t/D)^3)*1.125*10

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HP Required = Hp 749.722

HP provided= 740

No. of pumps provided = 2

Hp per pump = 370