JOINTS
SMS produces ductile iron pipe ranging from
DN 80 to DN 1600 as push-on, restrained or flanged type.
PUSH-ON TYPE
| T-type push-on joint can be easily and fast-assembled
hence very low labor is needed. |
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It requires no special equipment and can be applied
even under wet trench conditions.
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| The push-on joint provides an excellent leak proof environment.
This is due to the fallowing mechanism: |
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As the pressure of the water increases, the leak
tightness also increases, because, the pressure applied
by water through the gap between spigot and the socket
of other pipe to the gasket increases. As a result
the pressure applied by the gasket to the pipe increases.
If it is tested with extremely high increasing pressures,
to see where is the point of leakage; it is the destruction
of the pipe.
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One more important feature
of this joint is, ability of angular deflection and
small longitudinal movements.
Ability up to 5 degrees of deflection for each joint
allows easily diverted line without fittings. Ability
of small longitudinal movement is important especially
in aboveground applications where contraction and expansion
issues should be considered.
Also, due the ability of this deflections,
soil movements (like earthquake) does not damage the
pipeline. |
SELF RESTRAINED GASKET (DN80-400)
| The only difference from standard push-on
joint is the gasket used. This gasket has steel segments
embedded by vulcanization. |
Segment has an orientation
so that backward movement is hindered. That means, when
the line is pressurized, in thrust formation regions
backward movement is blocked against the tendency of
the joint to separate.
Therefore there will be no need to
concrete blocks, which are needed in trust formation
regions of the line (bends, tees, pipe ends, reducers,
etc.), or in loose soil, in sharp slopes etc. Keeping
in mind trust blocks needs extra effort, time and skilled
persons, restrained joints are easier and reliable to
use. |
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One big advantage of
this type joint is, field cut pipes can be also easily
restrained, because unlike the other type of restrained
joint it does not need a weld bead.
This type of joint should not be used
with gray cast iron pipes.
Allowable deflections are the same
as standard push-on joints. |
BOLTED RESTRAINED TYPE
Here the standard gasket
is used. Basically the same as push-on joint and it
possess all properties of push-on joints. In addition
it has a restrain mechanism, which consists of a gland,
bolts, retaining ring and weld bead. It can be considered
as a 'flexible flanged joint'. |
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It can be disassembled
easily, unlike the self restrained gasket.
When it is believed higher restrains
are needed this joint provides ultimate support. |
FLANGED TYPE
Main use of flanged pipes
is in aboveground pipelines where a rigid system is
required. Besides rigidity flanged pipes provides more
precision in the line. Also it enables to dismantle
the line easily. |
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