CONVEYANCE OR TRANSMISSION OF WATER
VARIOUS TYPES OF PRESSURE PIPES
Depending on the construction material the pipes are of the following types
i. C.I pipes
ii. Steel pipes
iii. RCC pipes
iv. Hume steel pipes
v. Vitrified clay pipes
vi. Asbestos cement pipes
vii. Miscellaneous pipes such as wrought iron pipes, PVC pipes.
For facilitating in handling transporting and placing in positions pipes are manufactured in small lengths of 2-6m. 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 depend on the pipe material, internal pressures and the condition of support.
VARIOUS TYPES OF JOINTS are
i. Bell and spigot joint
ii. Expansion joints
iii. Flanged joint Mechanical joint
iv. Mechanical joint
v. Flexible joint
vi. Screwed joint
vii. Collar joint
BELL AND SPIGOT JOINT
Design of pipes using monograms
For the known design discharge. The pipe dia are assumed in such a way that the velocity of flow varies from 0.6 to 3m/sec smaller velocity is assumed for pipes of smaller dia& larges velocity for pipes of larger dia. The loss of head in the pipe is then cal using hydraulic formulas.
Out of these formulas Hagen - William formula is more commonly used. The use of Hagen Williams formula however involves trial & error sol & in order to avoid this monogram of Hagen Williams formula has been developed. These are in all four variably
1. Discharge Q in m3/min or lit/sec
2. Dia of pipe in mm
3. Loss of heat in m/1000m light of pipe
4. Velocity of flow in m/sec
If out of 4 quantities any 2 are known. The other 2 can be found from the monogram. The monogram should in fig is valid for a value of roughness co-eff. C4 = 100. For any other value of CH the head loss obtained from the monogram is multiplied by the factor CH/100
Let the flow rate he 10m3/min & the dia of pipe he 400mm. It is required to find the head for a pipe of 800 m length.
Mark a point A corresponding to Q = 10m3/min discharge line & point B corresponding to dia = 400m the dia line from point A & B by means of straight be prolong the line AB to cut the head loss line at per velocity line at point D this we get head loss 1000m light = 7m
Hence the head loss for 800m length = (800x7) /1000 the velocity of flow comes to the 1.38m/sec.