From the magazine

Kembla expands into SWP rehabilitation

Kembla Watertech is well known throughout the Australian Trenchless Technology industry for its portfolio of quality techniques for the rehabilitation of both gravity and pressure pipes.

Over the 17-year history of this proudly Australian-owned and operated company, new technologies have been steadily introduced to meet the demands of the industry. These products have been either developed locally by Kembla (Tiger T junction seals) or introduced from overseas (Ex method).

Consistent with this track record of innovation, Kembla has formed a collaborative partnership with one of the originators of spiral wound pipe technology to introduce German engineering and quality to spiral wound pipeline rehabilitation.

The company said that “The addition of spiral wound pipe (SWP) to Kembla’s already impressive line-up of rehabilitation methods makes Kembla the only Australian contractor with the ability to assess, recommend, design and install every major class of rehabilitation method.”

Kembla SWP DiaFit Pipe Lining System

The ASTT website says the following about SWP: “Spirally wound liners are formed by taking a strip of plastic and winding it, locking the edges together to form a “÷pipe within a pipe’. The most advanced forms of this technology can be expanded to maximise the liner”÷s internal diameter, or are wound by a machine that traverses the pipeline winding the liner against the pipe wall.”

Kembla’s SWP DiaFit, as the name infers, is of the type that is expanded against the internal surface of the existing pipe, resulting in a tight fit to the internal diameter of the host pipe.

SWP is formed by a hydraulically-driven winding machine which is normally positioned in a manhole or small access excavation. The lead end of the tube rotates as it travels down the host pipe as further turns of the helix are added. The tube is of a smaller diameter than the host pipe and because it is not being simply pulled into the pipe (as with normal slip lining) the rotating tube “rides over” displaced joints etc.

During installation, the joint between adjacent turns of the helix is prevented from slipping by a secondary mechanical lock in the profile. Once the smaller-diameter tube has reached the opposite manhole, the winding machine continues to operate while a small wire is pulled through the secondary lock that releases the primary lock so that it can slide within itself. As this primary lock slides, the pipe expands progressively in diameter until a tight fit is achieved.

A major advantage of this system is that because there is a hollow opening along the entire length of spiral wound pipe, existing sewer flows in the pipeline can be accommodated during installation without the use of by-pass pumping or diversion. The sewer flow is usually only needed to be stopped for a short time during the actual expansion process.

SWP DiaFit linings are designed in accordance with AS/NZS 2566 Buried Flexible Pipes to provide a stand-alone structural liner where any contribution from the host pipe is ignored.

There is also an ASTM standard for spiral wound liner pipe: ASTM F1697-09 Standard Specification for Poly Vinyl Chloride (PVC) Profile Strip for Machine Spiral-Wound Liner Pipe Rehabilitation of Existing Sewers and Conduit.

This specification covers requirements and test methods for materials, dimensions, workmanship, stiffness factor, extrusion quality, and a form of marking for extruded PVC profile strips used for machine-made field fabrication of spirally wound pipe liners in the rehabilitation of a variety of gravity applications such as sanitary sewers, storm sewers, and process piping in diameters of 6-180 inches and for similar sizes of non-circular pipelines such as arched or oval shapes and rectangular shapes.

Profile strip produced to this specification is for use in field fabrication of spirally wound liner pipes in non-pressure sewer and conduit rehabilitation, where the spirally wound liner pipe is expanded until it presses against the interior surface of the existing sewer or conduit or, alternatively, where the spirally wound liner pipe is inserted as a fixed diameter into the existing sewer or conduit and the annular space between the liner pipe and the existing sewer or conduit is grouted.

Service with a spiral

Kembla Watertech now has the ability to offer its SWP DiaFit system where it is judged to be the most cost-effective answer for the specific requirements of a particular pipeline rehabilitation problem.

Kembla Watertech has a broad range of rehabilitation products for both gravity and pressure pipes and the addition of SWP DiaFit complements its already extensive portfolio of rehabilitation techniques, allowing Kembla to offer a fully comprehensive pipeline solution for every pipeline rehabilitation need.

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