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8/2/2019 Water Tank Pipes
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CALCULATION:
Length of pipe, L = 1.58 m
Diameter of pipe, D = 0.020 m
Area of pipe, A =( x(0.02) ) /4
= 3.142x10m
Volumetric flow rate of water = 9.80 L/min
= 1.63310 m/s
Mass flow rate of water = volumetric flow rate of water density of water
= (1.63310 ) 1000
= 0.1633 kg/s
Viscosity of water, = 0.8710 Ns/m
Velocity , v = volumetric flow rate / area of pipe
= (1.63310) / ( 3.142x10)
= 0.52 m/s
Re = (Dv)/
= (0.020.521000) / 0.8710
= 11954.02
Relative roughness factors for pipes
Material
Concrete
Cast Iron
Galvanized IronAsphalted Cast Iron
Commercial or Welded Steel
PVC, Glass, Other Drawn Tubing
Use relative roughness factor for PVC pipe = 0.0015mm
= 1.50 x 10 m
Roughness ration,e = / D
= (1.50x10) / 0.02
= 7.510
PVC ia a type of plastic. So that PVC pipe can also consider as smooth pipe.
Based on the graph of friction factors in pipe flow ,friction factor ,f =0.0070
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Pressure drop due to the friction of pipe :
P = 8fvL/2D
=8(0.007)(1.58)(1000)(0.52) / (2 x 0.02)
=598.12 Pa
V = v/2g
= 0.52/2(9.81)
= 0.01378
Miscellaneous Losses
Entry
Elbow
Gate valve
Globe valve
Tee, used as elbow
Exit
TOTAL
V = kv/2g
= 12.73(0.52)/2(9.81)
= 0.17544 m
Pressure drop due to fitting and bending:
P = g x head loss
= 1000 x 9.81 x 0.17544= 1721.1 Pa
Total Pressure Drop , P = pressure drop due to friction + pressure drop due to fitting and bending
= 598.12 +1721.1
= 2319.22 Pa
= 2.31922 kPa
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TEE,USED AS ELBOW
0.3m
0.06m GATE VALVE(FULLY OPEN)
TEE,USED AS ELBOW
0.45m
0.52m
TEE,USED AS ELBOW
Material of construction for the tank
The material of the construction of the tank is polyethylene water storage tank. The size of water tanks
mostly from 8 gallons to 12000 gallons. All of the polyethylene plastic storage tanks are from FDA approved
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materials and are suitable for collecting and storing water for drinking and other household uses.The shape o
can be vertical (tall round tanks), horizontal (long, low tanks with leg molded in) or rectangular (box shaped
The tank that use for my house is polyethylene .
The advantages of polyethylene water storage tank:
Reliable, Durable, Corrugated wall & Leak proof
Lightweight - easy handling (transportation & installation)
100% non sunlight UV penetration
Extremely Durable & Long Lasting
Rust & Rot Free
Seamless & Odourless
Non-Toxic / Food Grade
Won't rot or peel
Physical properties of polyethylene
Polyethylene is athermoplasticpolymerconsisting of long hydrocarbon chains. Depending on thecrystallinity
and molecule weight,amelting pointandglass transitionmay or may not be observable. The temperature at
which these occur varies strongly with the type of polyethylene. For common commercial grades of medium-
and high density polyethylene the melting point typically in the range 120 to 130 C (248to 266F). The melting
point for average, commercial, low-density polyethylene is typically 105 to 115 C (221to 239F).
Chemical properties of polyethylene
Most LDPE, MDPE and HDPE grades have excellent chemical resistance, meaning that it is not attacked by strong
acid or strong bases. It is also resistant to gentle oxidants and reducing agents. Polyethylene burns slowly with a
blue flame having a yellow tip and gives off an odour of paraffin. The material continues burning on removal of
the flame source and produces a drip.Crystalline samples do not dissolve at room temperature. Polyethylene
(other than cross-linked polyethylene) usually can be dissolved at elevated temperatures inaromatic
hydrocarbonssuch astolueneorxylene, or in chlorinated solvents such astolueneorxylene, or in chlorinatedsolvents such as trichloroethaneortrichlorobenzene.
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From the table which show the properties of construction materials,I think that polyethylene is the m
suitable material to construct the water storage tank.This is because the tensile strenghth of polyethylene
which is 6 - 37MPa which is more than enough to support the pressure of water in tank which is only
0.0064746 MPa. Furthermore, polyethylene is very resistant toward corrosive liquid such as acid and alkali.
Thus, it is safe to be used as the water storage tank in our house.
Pressure of water tank = gh= 10009.81o.66
=6474.6 Pa
=0.0064746 M Pa
Pressure of water in tank Is 0.0064746 MPa
PIPE MATERIAL
The pipe material that use for my house is PVC pipe,which is know as polyvinyl chloride pipe which is
made from a plastic and vinyl combination material. The pipes are durable,hard to damage, does not rust anlong lasting.This is the reason PVC pipe is commonly used in water systems,underground wiring ,and sewer
Polyvinyl chloride, commonly abbreviated PVC, is the third-most widely-produced plastic, after
polyethylene and polypropylene. PVC is widely used in construction because it is durable, cheap, and easily
worked.
It is used forsewerage pipesand other pipe applications where cost or vulnerability tocorrosion
limits the use ofmetal.PVC pipes can be fused together using various solvent cements or heat-fused,
creating permanent joints that are virtually impervious to leakage.
Besides that ,PVC pipe also safe to use.PVC is a useful material because of its inertness and is the basic ofits low toxicity.The main health and safety issuse with PVC are associated with "VCM", its carcinogenic precursor
,the products of its incineration (dioxins under some circumstances),the addives mixed with PVC,which include
heavy metals and potential endocrine disruptors.
ADVANTAGES OF PVC PIPE:
1).Healthy: ppr pipe material
2).Attrictive shape and light weight:little fluid resistance; soft color, beautiful shape; only1/8 that of metal pipe
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3).Energy saving and heat preservation:coefficient of heat conduction is only0.5% that of metal pipe.
4).Strong high temperature endurance:long-term service temperature:70. Short-term service temperature:95'
5).High pressure endurance:highest normal pressure can reach 95
6).Long service life:,over 50 years.
7).Convenient and reliable installation:hot melt connection, a connection can be finished within seconds
Physical Properties of PVC (Polyvinyl chloride)
Property
Density [g/cm3]
Thermal conductivity [W/(mK)]
Yield strength [MPa]
Young's modulus [psi]
Flexural strength (yield) [psi]
Compression strength [psi]
Coefficient of thermal expansion (linear) [mm/(mm C)]
Vicat B [C]
Resistivity [ m]
Surface resistivity []
By referring to the table above, polyvinyl chloride is suitable to be used as the material to make
pipes because it has high tensile strength which can withstand high tensile strength which can withstand
high pressure of water.
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(mm)
0.3 - 3.0
0.26
0.150.12
0.045
0.0015
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k Quantity Total
0.5 1 0.5
0.8 2 1.6
0.13 1 0.13
6 1 6
1.5 3 4.5
1 0 0
12.73
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ELBOW
0.25m
GLOBE VALVE
WATER TANK
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Rigid PVC Flexible PVC
1.3-1.45 1.1-1.35
0.14-0.28 0.14-0.17
31-60
490000
10500
9500
510-5
65-100
10 16 1012-1015
1013
-1014
1011
-1012
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WATER TANK
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GLOBE VALVE FULLY OPEN GATE VALVE
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commonplastic. The annual production is approximately 80 million metric tons.[1]
Its primary use is
withinpackaging(plastic bag, plastic films,geomembranes, etc.). Many kinds of polyethylene are known, but they
almost always have thechemical formula(C2H2)nH2. Thus PE is usually a mixture of similarorganic compoundthat
differ in terms of the value of n.
thecrystallinityandmolecular weight, amelting pointandglass transitionmay or may not be observable.
The temperature at which these occur varies strongly with the type of polyethylene. For commoncommercial grades of medium- and high-density polyethylene the melting point is typically in the range 120
to 130 C (248to 266F). The melting point for average, commercial, low-density polyethylene is typically
105 to 115 C (221to 239F).
by strong acids or strong bases. It is also resistant to gentle oxidants and reducing agents. Polyethylene
burns slowly with a blue flame having a yellow tip and gives off an odour of paraffin. The material continues
burning on removal of the flame source and produces a drip.Crystalline samples do not dissolve at room
temperature. Polyethylene (other than cross-linked polyethylene) usually can be dissolved at elevated
temperatures inaromatic hydrocarbonssuch astolueneorxylene, or in chlorinated solvents such
astrichloroethaneortrichlorobenzene.