Joints (Bağlantı Şekilleri)

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.  

It requires no special equipment and can be applied even under wet trench conditions.
The push-on joint provides an excellent leak proof environment. This is due to the fallowing mechanism:  

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.

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.

  

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'.
  

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.