Joining technology

Socket joints for ductile cast-iron pipes and fittings

Our ductile cast-iron pipes and fittings can be supplied with various types of socket joint. A distinction is made between longitudinal positive locking and non-longitudinal positive locking joints.

BLS® joint

Cross-section of BLS socket

Duktus offers positive locking BLS® socket joints for pipes and fittings.

This high-strength, easy-to-fit joint is suitable for even the most extreme applications. Depending on the nominal size, the joint is compatible with component operating pressures of up to 110 bar and angular deflection of up to 5°. The BLS® socket joint is available in nominal sizes from DN 80 to DN 1000.

Positive locking push-in joints can be recognised by the welding bead on the spigot end and their retaining chamber. The positive locking interengagement between the welding bead and the retaining chamber is achieved through the use of locking segments. This system permits the mechanical transfer of forces between the spigot end and the socket of the next pipe or fitting.

Forces may arise as a result of internal pressure or external tractive forces. The permitted operating pressures and allowable tractive forces depend on the nominal diameter and are indicated in our brochures and catalogues (see below). Higher pressures and tension forces can be accommodated in consultation with our application technology department.

BRS® joint (also known as TYTON®-SIT-PLUS®)

BRS® joint

BRS® is available in nominal sizes from DN 80 to DN 600 for pipes and fittings. This joint is based on the TYTON® joint. Replacing the TYTON® gasket with a TYTON®-SIT-PLUS® gasket gives the friction-locking BRS® system, with deflection capability of up to 3° per socket.

Applications/benefits

Pipes and fittings with non-positive locking joints are primarily designed for use in conventional open-trench installations. They are also used in pipe relining applications (see DVGW-GW 320-1) with TYTON® pipes.

Before using non-positive locking joints in culvert and bridge pipelines or open pipelines, or before installing on steep slopes or in protective tubes, collectors or on unstable ground, always consult our application technology department.

Thrust blocks (e.g. as per DVGW-GW 310) must be fitted in non-restrained bends, branches, reductions etc. However, this is not necessary with the friction-locking BRS® system. The stretch of pipeline to be protected must be designed in accordance with DVGW-GW 368 or the entire installation must use the BRS® system.

Friction-locking joint systems are generally used where thrust blocks are replaced or not used at all.

Non-positive locking joints

This includes TYTON® socket joints, screw-gland socket joints and bolted-gland socket joints.

TYTON® joint

Cross-section of TYTON socket

The TYTON® socket joint can be found in virtually every pipe and in most fittings. At first glance, the features that guarantee the exceptional performance of the TYTON® socket joint – tried and tested over decades of use – may not be immediately obvious. But pipe systems fitted with these proven socket joints are completely sealed against leaks, even in the case of excess internal pressure, off-centre alignment and external pressure caused by groundwater pushing against the pipe, for example. The system remains leakproof even if longitudinal forces and angular deflection come into play as a result of traffic and soil movements.

The socket system, acting as a joint, follows the soil movements without transferring bending moment to the next pipe or fitting. These characteristics are all thanks to the high degree of dimensional stability and the design of the socket.

The TYTON® socket joint is not affected by roots; it has a high load-bearing capacity and can withstand angular deflection of up to 5°, depending on the nominal size.

  • with TYTON® socket joint in accordance with DIN 28 603 (form A)
    DN 80 to DN 600
  • with TYTON® socket joint in accordance with DIN 28 603 (form B, long socket)
    DN 700 to DN 1000

The screw-gland and bolted-gland socket joints are only used in a small number of fittings, such as EU fittings and collars.

Flanged joints/flanged pipes

Flanged joints made from ductile cast iron in accordance with DIN EN 1092-2 for drinking water supply and waste water disposal.

Flanged joints should ideally be used in above-ground pipelines, in locations such as pump rooms, water treatment plants, pipe cellars or overhead tanks. They can also be used in underground pipeline constructions around gate valve junctions. These longitudinal positive locking joints do not move and they transfer longitudinal and bending forces from pipe to pipe.

Flanged pipes are either made from centrifugally or conventionally cast pipes. In centrifugally cast flanged pipes, the flanges are generally pre-welded into position; however, they can also be screwed into place.

Flanged pipes with cast flanges are produced in a sand casting process.
Flanged pipes can be supplied with various coatings and linings.

Installation videos

Installation of a BLS® DN 80 to DN 500 joint

Installation of a BLS® joint. This is a form-fitting joint. Typical areas of application include snow making systems, turbine pipelines, transport pipelines, inclined pipelines and pipelines laid above ground level. Ductile cast iron pipes with the BLS® joint can also be laid trenchless.

Installation of a BLS® DN 600 to DN 1000 joint

Installation of a BLS® joint. This is a form-fitting joint. Typical areas of application include snow making systems, turbine pipelines, transport pipelines, inclined pipelines and pipelines laid above ground level. Ductile cast iron pipes with the BLS® joint can also be laid trenchless.

Shortening and welding a pipe with a BLS® joint

Shortening a ductile cast iron pipe and subsequent application of a BLS® welding bead on the construction site.

Installation of a BRS® push-in socket joint

The BRS® joint (also TYTON®-SIT-PLUS®) is available in a range of nominal diameters from DN 80 to DN 600. This longitudinal positive locking socket joint establishes a friction-locking connection. The BRS® joint is created by using a TYTON®-SIT-PLUS® seal in a TYTON® pipe or fitting.

Installation of a TYTON® socket joint

Installation of a TYTON® socket joint in accordance with DIN 28 603. Duktus offers the TYTON® joint in a range of nominal diameters from DN 80 to DN 1000. Replacing the TYTON® sealing ring with a TYTON®-SIT-PLUS seal creates the BRS® longitudinal positive locking socket joint, which is available in a selection of nominal diameters between DN 80 and DN 600.

Downloads

Product information