BW PERUNDING SDN. BHD. COMPANY NO. 27875 P

CALCULATION SHEET

JOB: TAIPING HEADWORK CONTRACT NO.: MIG

PART OF WORK: Filter backwash Air scour

GROUP: M&E ASSISTANT: WNWA CHECKED BY: WNWA

DATE: 1/12/2009 FILE: 'file:///tt/file_convert/55cf91bc550346f57b903078/document.xlsx'#$WNWA

To determine the air blower size for back washing of the filter.

No of filter to be backwashed at one time = 1 no

Rate of air scour = 50 m3/m2/hr (Min) (Separate Air Water Wash System)60 m3/m2/hr (Max)

Air Scour Pressure= 0.35 bar = 3.5 m

Filter Length = 5.5 mFilter Width = 7.3 mFilter area = 40.15 m2

Therefore for MAX rate,the air required 2409 m3/hrAdd 10% safety factor = 2649.9 m3/hr

= 736.0833 l/s = 1558.5 cfm = 44.17 m3/min

Therefore for MIN rate,the air required 2007.5 m3/hrAdd 10% safety factor = 2208.25 m3/hr

= 613.4028 l/s = 1298.7 cfm = 36.80 m3/min

Air blower level = 117.15 mHighest air blower pipes = 125.6 mTotal static = 8.45 m

= 0.828431 bar

Pressure required min with 20% for losses and static loss = 1.414118 bar = 14.4 meter head = 20.5047 psi

Air Blower Selected: 2649.9 m3/hr @ 14.4 meter head

CALCULATION SHEET

JOB: Taiping Headwork Air Blower Pressure Calculation CONTRACT NO.:

PART OF WORK: Air Blower Calculations

GROUP: ASSISTANT: CHECKED BY:

DATE: 19/Apr/23 FILE: 'file:///tt/file_convert/55cf91bc550346f57b903078/document.xlsx'#$Air Blower Sizing

1.0 To determine the Air Blower Capacity:

* No. of filter to be backwashed at the same time = 1 No.

(Separate Air Water Wash System)

* Rate of air scour = 50 (Min)

60 (Max)

(Refer to the MWA's guideline)* Air Scour Pressure = 0.35 bar

= 3.5 m

* Filter area:Filter Length = 5.5 mFilter Width = 7.3 m

Filter Area = 40.15

* For maximum rate,the air required = 2409.00

Add 10% safety factor = 2649.9

= 736.0833 l/s

For minimum rate,the air required = 2007.50

Add 10% safety factor = 2208.25

= 613.4028 l/s

.: Therefore, the capacity of air blower = 2649.9

2.0 Air Blower Pressure Calculation:

* At ambient suction conditionSuction Pressure = 32

= 305.15 °KSuction Pressure = 1013.25 milibar abs

Blower Capacity = 2649.9

Ambient Air Density = 1.160 (How do you get this?)

Ambient Air Kinematic Viscosity = 0.00

BW PERUNDING SDN. BHD.(COMPANY NO. 27875 P)

m3/m2/hr

m3/m2/hr

m2

m3/hr

m3/hr

m3/hr

m3/hr

m3/hr

°C

m3/hr

kg/m3

m2/s

* At operating conditionDischarge Pressure = 71

= 344.15 °KAssume Discharge Pressure = 1450.00 milibar abs

Discharge Flow Rate = 1930.48

Discharge Air Density = 1.472 (How do you get this?)

Discharge Air Kinematic Viscosity = 0.00

* Static condition(Refer to the drawings)

Also, = Volume ratio

where - Suction flow

- Motive water flow

Hence, = 0

= #REF! = ### l/s

.: = #REF! = ### l/s

Let = 1.0 m/s

= #REF! mm say 200 mm

No of hoppers per bay, n = 3

and = +

.: = #REF! = ### l/s

Let = 1.0 m/s

= #REF! mm say 150 mm (ID)

Area of pipe = 0.017671

= #REF! m/s

°C

m3/hr

kg/m3

m2/s

Rw Qs / Q1

Qs

Q1

Qs Q1

Qs m3/min

Q1 m3/min

V1

f1

Q2 Q1 / n Qs

Q2 m3/min

V2

f2

m2

V2

= m/sat nozzle = 0.0 m/s

= #REF! mm

CHECK:1 N/mm2 = 145 psi

1 psi = 0.006897 N/mm210m head = 0.09807 N/mm2

1 psi = 0.703227 m head1 m of head = 1.422015 psi

3.0 Ejector Sizing

To calculate the duty of the sand ejector pumpset,Discharge pipe diameter = 100.00 mm

Lower end level of discharge channel = -1 m ELTop level of discharge pipe = 7.5 m EL

Discharge static head = 8.5 m = 12.09 psi

Assume discharge back pressure of = 10.0 m

From the Performance Curve, at discharge back pressure of 10.0 m, the followingdata are obtained.

Motive water flow rate = 39.0

Total agitation flow rate = 11.0

Suction flow rate = 17.0Motive water pressure = 44.0 m

Hence,

Motive water flow per eductor = 50.0Nos. of eductor = 2

Motive water flow for all eductors = 100.0

Eductor discharge flow rate = 56.0

4.0 Motive Water Pipe Loss

William-Hazen's Formula: =

Flow Rate Size Velocity Length Hazen K QtyQ D L William

(m) (m/s) (m) C

Motive water velocity VN (2g (H1-Hs))0.5

.: Nozzle diameter

m3/hr

m3/hr

m3/hr

m3/hr

m3/hr

m3/hr

Hf 10.666 x C (-1.85) x D (-4.87) x Q (1.85) x L

(m3/s)

1 Motive Water Pipe Loss

Suction Pipe:

a) Pipe Loss 0.028 0.2 0.89 8 90 0

Flow Rate Size Velocity Length Hazen K QtyQ D L William

(m) (m/s) (m) C

Fitting Loss:a) 90 deg bend 0.028 0.2 0.89 90 1 3 0b)c)

4.0 Motive Water PumpProvide 2 No. pumps (1 duty / 1 standby)

Motive Water Pump capacity required = #REF! l/sAllow for 5% fitting losses = #REF! l/s

Let Motive Water Pump capacity = 25.10 l/s = 90.36

Inlet pressure = 0.00 psi = 0.0 mLet Pump Head = 61.5 m

Check pipeworksLength of mains = 30 m

Allow for 5% fitting losses = 31.5 mFlow rate in l/sec = 25.10 l/sec

= 0.0251Pipe diameter = 200 mm f.i.d= 204 mm

Pipeline velocity = 0.77 m/secHazen William C value = 110

Head loss = 0.14 mTotal back pressure = 8.64 m = 12.28451 psi

FAIL!

(m3/s)

m3/hr

Flow rate in m3/sec m3/sec