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DUCTILE
IRON FITTINGS - HOWTO - METHODS OF JOINTING |
Jointing Procedure of Mechanical
Joint Fittings
- Clean the socket of the fitting and the
spigot of the pipe thoroughly. All lumps, blisters and excess coating material should be
removed from the socket and spigot end.
- Put the follower gland and the gasket on the
spigot of the pope.
- Bring the fittings closer and insert the
spigot into the socket. Ensure that the pipe and fittings are properly aligned.
- Insert the nut-bolts one by one. Tighten
diametrically opposite bolts to the recommended torque.
- Ensure that the bottom end of the follower
gland presses the rubber gasket properly.
- Ensure joint deflections are within the
allowable tolerances.
- In case of any leakage the bolts may be
tightened further.
Flanged Joint
Fittings
Flanged Joints are self-restrained rigid
joints. Flanged joints for working pressure ratings of 1.0 MPa (PN 10), 1.6 MPa (PN 16),
2.5 MPa (PN 25), and 4.0 MPa (PN 40) are made.
Jointing Procedure Of Flanged
Joints
- Ensure that faces of the flanges are clean
and free from dirt or particles of foreign matter.
- Inspect gasket to ensure it is undamaged
- The gasket used between flanges of pipes
should be made of compressed fibre-board or natural/synthetic rubber as per IS: 638
- Bolt adjoining flanges
- Flanged joints should be bolted in the
correct sequence and to the appropriate torque. Tighten four location bolts in the order
required to roughly secure the adjoining flange.
- Insert remaining bolts and tighten
diametrically opposite bolts to the recommended torque. Check that all bolt holes are filled
One should be careful in
specifying the valves considering the working pressure and the flange drilling (which are
different for different pressures). In India, most of the valves are with PN 10 drilling.
In case the valves are specified with PN 16 or PN 25, the drilling of the flanges can be
matched accordingly. However, clear recommendation should be given in the order. Normally,
if nothing is mentioned about the flange drilling, all flanges will be faced and drilled
to PN 10 configuration.
Jointing by Crowbar
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Jointing by Puller
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Jointing
by Jointing Tackle
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Jointing
by Chain or Rope Pulley |
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