WATER AND WASTE WATER ENGINEERING- DIPLOMA GTU

Chapter-4
TOPIC:CONVEYANCE OF WATER
BY : D.D.DATTANI
(M.E.TRANSPORTATION)

CONVEYANCE OF WATER
BY : DHARA D.DATTANI 2

CONVEYANCE OF WATER

1. CONVEYANCE OF WATER
2. TYPES OF PIPES USED FOR CONVEYANCE OF WATER
3. PIPE JOINTS
4. LAYING OF PIPELINE
5. METHODS OF WATER DISTRIBUTION
6. LAYOUT OF DISTRIBUTION NETWORKS
INDEX

 Water is drawn from the sources by Intakes. After it’s drawing the next
problem is to carry it to the treatment plant which is located usually within
city limits. Therefore after collection, the water is conveyed to the city by
mean of conduits. If the source is at higher elevation than the treatment
plant, the water can flow under gravitational force.
 For the conveyance of water at such places we can use open
channel,aqueduct or pipe line, Mostly it has been seen that the water level in
the source is at lower elevation than the treatment plant, In such case water
can be conveyed by means of closed pipes under pressure
1.CONVEYANCE OF WATER

INTAKE OF WATER

 If the source of supply is underground water, usually there is no problem as,
these sources are mostly in the underground of the city itself.
 The water is drawn from the underground sources by means of tube-wells
and pumped to the over-head reservoirs, from where it is distributed to the
town under gravitational force.
 Hence at such places there is no problem of conveyance of water from
sources to the treatment works.
CONVEYANCE OF WATER

WATER CONVEYANCE SYSTEM
FREE FLOW
SYSTEM
PRESSURE
SYSTEM
1.CANALS
2.FLUMES
3.GRADE
AQUEDUCTS
4.GRADE
TUNNELS
PRESSURE
AQUEDUCTS
PRESSURE
TUNNELS
PRESSURE
MAINS
INVERTED
SYPHOS
WATER CONVEYANCE SYSTEM

WATER CONVEYANCE SYSTEM-
FREE FLOW SYSTEM
CANALS FLUMES

WATER CONVEYANCE SYSTEM-
FREE FLOW SYSTEM
GRADE AQUEDUCTS GRADE TUNNELS

 These are circular conduits, in which water flows under pressure.
 Now a days pressure pipes are mostly used at every places and they have
eliminated the use of channels, aqueducts and tunnels to a large extent.
 These are made of various materials like cast Iron, wrought Iron, steel,
cement Concrete, asbestos, cement, timber, etc.
 In distribution system pipes of various diameter, having many connections
and branches are used.
 Water pipe lines follow the profile of the ground water and the location
which is most economical, causing less pressure in pipes is chosen.
PIPES

CONVEYANCE OF WATER

 The cost of pipe line depends on the internal pressure to bear and the
length of pipe line.
 Therefore as far as possible the hydraulic line is kept closer to the pipe line.
 In the valley or low points a scour valve is provided to drain the line and
removing accumulated suspended matter.
 Similarly at high points air relief valves are provided to remove the
accumulated air.
To prevent the bursting of pipes due to water hammer, surge tanks or stand
pipes are provided at the end of pipes.
CONVEYANCE OF WATER

The selection of material for the pipes is done on the following points
 Carrying Capacity of the pipes
 Durability and life of the pipe
 Type of water to be conveyed and its corrosive effect on the pipe material.
 Availability of funds
 Maintenance cost, repair etc..
 The pipe material which will give the smallest annual cost or capital cost will
be selected, because it will be mostly economical.
CONVEYANCE OF WATER

SURGE TANK OR SURGE CHAMBER

1. CAST-IRON PIPE
2. WROUGHT IRON PIPE
3. STEEL PIPE
4. R.C.C (REINFORCED CEMENT CONCRETE PIPE)
5. PSC PIPES (PRE-STRESSED CONCRETE PIPE)
6. ABSESTOS CEMENT PIPE
7. PLASTIC PIPE
8. COPPER PIPE
9. GLASS REINFORCED PLASTIC PIPE
TYPES OF PIPES USED FOR CONVEYANCE
OF WATER

Out of the types mentioned, plastic or PVC and Asbestos cement pipes,
wooden pipes are not generally used for conveyance of water. They are used
in house drainage or water connection within individual house.
PIPES

 Cast – Iron Pipes are mostly used in water supply schemes.
 They have higher resistant to corrosion, therefore have long life about 100
years.
 Cast Iron pipes are manufactured in lengths of 1.5 m to 5.5 m.
 The fittings of these pipes are also manufactured in sand moulds having
core boxes.
 These fittings are also weighed, coated with coal tar and finally tested.
 Cast-Iron pipes are joined together by means of Bell and Spigot, Threaded
or flanged Joints
CAST IRON PIPES

CAST IRON PIPES

ADVANTAGES
Ease in jointing the pipes
 Can withstand high Internal
pressure
 Have a very long design life. (100
years)
 They are less prone to corrosion.
 They are having moderate cost
DISADVATNAGES
They cannot be used for pressures
greater thang 7kg/cm
 They are heavier uneconomical &
diameter are more than 120cm
 They are fragile (likely to break
during transportation)
CAST IRON PIPES

DAMAGES IN CAST IRON PIPES

WROUGHT IRON PIPE

 Wrought Iron Pipes are manufactured by rolling the flat plates of the metal
to the proper diameter and welding the edges.
 To Increase the life of these pipes sometimes these are galvanized with zinc
WROUGHT IRON PIPE

ADVANTAGES
Can be easily cut, threaded and
work
 Give neat appearance
DISADVANTAGES
Costlier in compare to C.I. Pipes
 It can only use inside buildings,
where place is protected from
corrosion
WROUGHT IRON PIPE

STEEL PIPES

 It can be used as, Rising mains, conveying mains, distribution system,
inverted syphos and on bridges and other structure where strength and low
weight are required
 It can bear high internal pressure
 Diameter size : 0.9m to 3.0m
STEEL PIPE

ADVANTAGES
They can be easily transported
 They are easily available
 They are easy to construct
DISADVANTAGES
They cannot handle external loads
 Their life is half than C.I. pipes
 They cannot used in water
treatment plant connection
STEEL PIPE

REINFORCED CEMENT CONCRETE PIPE

 Cement concrete pipe may be either plain or reinforced
 It is manufactured in smaller size ( upto maximum 0.6m diameter)
 They are cast-in-situ or precast
 These pipes may be precast or Cast-in-situ plain concrete pipe may be used
at such places where water does not flow under pressure,
 These pipes are jointed with Bel & Spigot Joints.

ADVANTAGES
 Their life is more about 65 years
 They can be easily constructed in the factories or
at site
 They have least coefficient of thermal expansion
than other types of Pipes
 They do not require expansion joints
 Due to their heavy weight, when laid under
water, they are not affected by buoyancy, even
when they are empty.
 They are not affected by atmospheric action or
ordinary soil under normal condition.
DISADVANTAGES
They are affected by acids, alkalis
and salty waters
 Their repairs are very difficult.
 Due to their heavy weight, their
transportation and laying cost is
more.
 It is difficult to make connections in
them
 Porosity may cause them to leak
due to shrinkage cracks and porosity

ASBESTOS CEMENT PIPES

Manufactured from asbestos cement and fibres
Diameter of pipe : 5cm to 130cm in five different grades
Internal pressure : 3.5kg/cm2 – 14kg/cm2 as per IS 1592 : 1989

ADVANTAGES
 They have smooth internal surface
 Less friction losses
 They are light in weight
 They can be easily cut, fitted or
jointed
 They are anti corrosive
 No expansion joint required
DISADVANTAGES
They are costly
 They are not durable
 They are soft and brittle
 They cannot be laid in exposed
places

PLASTIC PIPES

They are use commonly because of their properties like, corrosion resistant,
highly weighted, economical
Pipes available in market
Low density polyethylene pipe
High density polyethylene pipe
Un-plasticised polyvinyl chloride pipe
PLASTIC PIPES

 For the facilities in handling, transporting, and placing in position, pipes are
manufactured in small lengths of 2 to 6 meters.
These small pieces of pipes are then joined together after placing in position
to make one continuous length of pipe.
 The design of these joints mainly depends on the material of the pipe,
internal water pressure and the condition of the support
 The bell and spigot joints, using lead as filling material is mostly used for
cast Iron pipes.
 For Steel pipes welded, riveted, flanged or screwed joints my be used.
PIPE JOINTS

PIPE JOINTS

Various pipe joints :
1.Bell and spigot joint
2. Flanged joint
3. Flexible joint
4. Expansion joint
5. Collar joint
PIPE JOINTS

SPIGOT AND SOCKET JOINTS

 This types of joints is mostly used for cast iron pipes
 For the construction of this joint the spigot or normal end of one pipe is
slipped in socket or bell mouth end of the other pipe until contact is made at
the base of the base of the bell.

 Sometimes wet clay is used to make tight contact between the runner and
the pipe so that hot lead may not run out of the joint spaces.
 The molten lead is then poured into V-shaped opening left in the top by the
clamp joint runner.
 The space between the hemp yarn and the clamp runner is removed, the
lead which shrink while cooling, is again tightened by means of chalking tool
and hammer.
 Now a days in order to reduce the cost of lead certain patented compounds
of sulphur and other materials and other materials are filled in these joints.

FLANGED JOINT

 This joint is mostly used for temporary pipe lines, because the pipe Line can
be dismantled and again assembled at other places.
 The pipe in this case has flanges on its both ends, cast, welded or screwed
with the pipe.
 The two ends of the pipes which are to be jointed together are brought in
perfect level near one another and after placing of washer or gasket of
rubber, canvas, copper or lead between the two ends of flanges is very
necessary for securing a perfect water-tight joints.
 These joint cannot be used at places where it has to bear vibration of pipes
etc..
FLANGED JOINT

FLEXIBLE JOINT

Sometimes this joint is also called Bell & Socket or Universal Joint.
This joint is used at such places where settlement is likely to occur after the
lying of the pipes.
This joint can also be used for laying of pipes on curves, because at the joint
the pipes can be laid at angle.
This is a special type of joint. The socket end is cast in a spherical shape.
The spigot end is plain but has a bead at the other end.
 For the assembling of this joints, the spigot end of one pipe is kept in the
spherical end of the other pipe.
FLEXIBLE JOINT

FLEXIBLE JOINT

 After this the retaining ring is slipped which is stretched over the bead.
 Then a rubber gasket is moved which touches the retainer high after it split
cast iron gland ring is placed,
 The outer surface of which has the same shape as inner surface of socket
end.
Over this finally cast iron follower ring is moved and is fixed to the socket
end by means of bolts. It is very clear that if one pipe is given any deflection
the ball shaped portion will move inside the socket, and the joint will remain
waterproof in all the position.
FLEXIBLE JOINT

EXPANSION JOINT

This joint is used at such places where pipes expand or contract due to change in
atmospheric temperature and thus checks the setting of thermal stresses in the
pipes.
In this joints the socket end is flanged with cast iron follower ring, which can freely
slide on the spigot end or plane end of other pipes. An elastic rubber gasket is tightly
pressed between the annular spaces of socket by means of bolts.
In the beginning while fixing the follower ring some space is left between the socket
base and the spigot end for the free movement of the pipes under variation of
temperature.
In this way when the pipe expands the socket end moves forward and when the pipe
contracts, it move backward in the space provided for it. The elastic rubber gasket in
every position keeps the joint water tight.
EXPANSION JOINT

COLLAR JOINT

 This type of joint is mostly used for joining big diameter concrete and
asbestos cement pipes.
 The ends of the two pipes are brought in one level before each other.
 Then rubber gasket between steel rings or jute rope socked in cement is
kept in the grove and the collar is placed at the joint so that it should have
same lap on both the pipes.
 Now 1:1 cement mortar is filled in the space between the pipes and the
collar.
COLLAR JOINT

STEP : 1 – MARKING OF CENTRE LINE
STEP : 2 – EXCAVATION TRENCH
STEP : 3 – SIDE PROTECTION TRENCH
STEP : 4 – PREPARATION OF SUBGRADE
STEP : 5 – LOWERING AND JOINING OF PIPES
STEP : 6 – TESTING OF PIPELINE
STEP : 7 – BACKFILLING TRENCH
LAYING OF PIPELINE

 For efficient distribution system adequate water pressure required at
various points.
 Depending upon the level of source, topography of the area and other local
conditions the water may be forced into distribution system by following
ways.
METHODS OF WATER DISTRIBUTION

 GRAVITY SYSTEM
 DIRECT PUMPING SYSTEM
 COMBINED GRAVITY AND PUMPING SYSTEM
METHODS OF WATER DISTRIBUTION

METHODS OF WATER DISTRIBUTION-
GRAVITY SYSTEM

 Suitable when source of supply is at sufficient height.
 Most reliable and economical distribution system.
 The water head available at the consumer is just minimum required.
 The remaining head is consumed in the frictional and other losses.
GRAVITY SYSTEM

PUMPING SYSTEM

 Treated water is directly pumped in to the distribution main with out
storing.
 Also called pumping without storage system.
 High lifts pumps are required.
 If power supply fails, complete stoppage of water supply.
 This method is not generally used.
DISADVANTAGE :
 Pumping is costly
 Continuous supervision at the pumping station is necessary.
PUMPING SYSTEM

COMBINED GRAVITY & PUMPING SYSTEM

 Most common system.
 Treated water is pumped and stored in an elevated distribution reservoir.
 Then supplies to consumer by action of gravity.
 The excess water during low demand periods get stored in reservoir and get
supplied during high demand period.
 Economical, efficient and reliable system.

Advantages :
 Pump at work at convenient schedule
 Uniform pressure can be maintained during water supply
 Distribution reservoir can be used when pump Failure during power failure
 The quality of water will improve due to detention of water in the elevation
reservoir
 Economical, efficient and reliable system.

1. The quality of water should not get deteriorated in the distribution
2. Every consumer should get sufficient water at desired pressure.
3. The design and layout should be economical.
4. It must be capable of being maintained easily and economically.
5. Adequate quantity of water must always be available to put-out an emergency
fire.
6. It should be so designed that even during breakdown or repairs line, water
should reach that locality from other line.
7. During repair work it should not cause obstruction to the traffic.
8. All distribution pipes should be preferably laid 1 m away or above sewer lines.
9. All pipes should be of good quality and leakages through
REQUIREMENT OF AN IDEAL DISTRIBUTION
SYSTEM

 The purpose of distribution system is to deliver water to consumer with
appropriate quality, quantity and pressure.
 Distribution system is used to describe collectively the facilities used to
supply water from its source to the point of usage.
LAYOUT OF DISTRIBUTION NETWORK

 DEAD END SYSTEM
 GRID IRON SYSTEM
 RING SYSTEM
 RADIAL SYSTEM

 It is suitable for old towns and cities having no
definite pattern of roads
 This is also called Tree system
 In this system, there is main supply pipe, from
which originates (generally at right angles) a
number submain pipes. Each submain, then
divides into several branch pipes, called laterals
 This system is suitable for old towns and cities
having no definite pattern roads.
 The water supply mains have then to be taken
along the main roads branches taken off
wherever needed, thus resulting in the
formation of a number dead ends
DEAD END SYSTEM

ADVANTAGES
The design calculations are simple and
easy. It is possible to determine
discharge and pressure in each pipe
very accurately.
 Lesser number of cut off valves
(i.e. sluice valves) are required.
 Pipe laying is simple.
 Shorter pipe lengths are needed.
 It is cheap and simple and can be
extended easily.
DISADVANTAGES
 Due to a number of dead ends in the
system, there is stagnation of water and
accumulation of sediment at dead ends.
 A large number of scour valves are
required at dead ends, for the removal of
sediments
 During repairs, the large portion of
distribution area is affected.
 Since in this system, the discharge is
reaching a point from only one direction
the supplies during fire fighting cannot
be increased by diverting any other
DEAD END SYSTEM

 This system is also known as 'reticulated
system' or 'interlaced system
 It is most convenient for towns having
rectangular layout of roads.
 Actually, this system is an improvement
over dead-end system. All the dead ends
are interconnected with each other and
water circulates freely throughout system.
GRID IRON SYSTEM

ADVANTAGES
There is free circulation of water, without
any stagnation or sediment deposit.
 Due to inter connection, water is
available at each point with minimum
loss of head.
 In case of repairs, only very small area
of the distribution system is affected.
Enough water is available in the streets
for fire fighting, since hydrants will draw
water from more than one side.
DISADVANTAGES
This system requires more length
of pipe lines and a large number of
sluice valves(i.e. cut-off valves).
Construction is costlier
Analysis of pressure ,discharge
and velocities are difficult
If one section is to be repaired ,
many number of valve needs to be
closed
GRID IRON SYSTEM
69

RING SYSTEM
 The supply main is laid all along the
peripheral roads and sub mains branch out
from the mains.
 This system also follows the grid iron
system with the flow pattern similar in
character to that of dead end system.
 So, Determination of the size of pipes is
easy.
 Water can be supplied to any point from at
least two directions.

RADIAL SYSTEM
• The area is divided into different zones.
• The water is pumped into the distribution
reservoir kept in the middle of each zone.
• The supply pipes are laid radially ending
towards the periphery.
•ADVANTAGES :
• It gives quick service.
• Calculation of pipe sizes is easy

WATER AND WASTE WATER ENGINEERING- DIPLOMA GTU

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