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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