Sealing sock makes the right connections

Two industry giants have joined forces to bring a new lateral connection sealing system to the global market. And the signs are very positive that Interflow’s Interfit, with Fluvius’s help, will make a difference all around the world.

ANYONE EVEN remotely familiar with the trenchless technology industry in the southern hemisphere will know the name Interflow, a company with some 75 years’ experience in the pipeline industry and, since 1991, a leading provider in Australia and New Zealand of repair, rehabilitation and renewal services for deteriorated underground non-pressure pipelines.

More recently the company has been instrumental in developing home-grown technologies including the Interfit system for lateral connection sealing. In Europe, Düsseldorf-based Fluvius provides an extensive range of services for pipe and sewer renovation.

Now these two industry names have joined forces to bring Interflow’s Interfit lateral connection sealing system to the broader global market.

Approved for use in Australia since 2001, Interfit has been utilised to complete more than 40,000 lateral connection repairs and seals to date. The system is designed to effectively seal lateral connections subsequent to lining the main to establish a fully sealed renovated pipe network. Investigations have shown that the system provides installations with a very low failure rate.

Interfit is applicable to main pipelines from 150mm to 300mm diameter, with lateral connections of 100mm and 150mm diameter where it can provide strong and robust structural seals that are installed from inside the main pipe without the need for surface excavation. As most of the world’s lateral connections fall into this size range, the system can be utilised on a high percentage of junctions.

Based on a patented sock design, the Interfit process uses a proprietary resin ensuring that installation is simple and fast while being very effective. The sealing sock can be designed to accommodate lateral connections with incident angles to the main pipeline from 0° to 90°, covering most commonly encountered circumstances.

The patented sock design comprises a PVC-coated glass fibre flat sheet that is shaped and stitched lengthwise according to the requirements of the lateral connection being sealed.

The resin utilised for the installation of the sealing sock is a two-part silicate resin that has a long pot life (20 minutes) while offering a short cure time (30 minutes) without the need for heating or UV curing.

This allows time for operators to properly prepare the seal before installation and ensure high productivity with the short cure time allowing several installations daily if required. Application of the resin to the sock also utilises innovative technology to ensure an efficient impregnation operation on site.

Once prepared the seal is fitted to a small, lightweight, low friction, flow-through and low cost installation packer that is easy to use and has no moving parts or electrical requirements. The packer design can accommodate pipe sizes from 150mm to 300mm and is available as a short or long lateral arm version depending on the length of installation required into the lateral connection. The integrated flow function means that installations can be undertaken without the need to fully seal off the main pipe flows.

With the seal fitted the loaded packer is pushed, or pulled, depending on access requirements, into position along the cleaned mainline pipe to the lateral to be sealed. The seal is placed into the lateral during this positioning operation.

Once in place the packer is inflated with compressed air pushing the impregnated seal against the inner walls of both the mainline pipe and the lateral. Whilst cure time is just 20 minutes, to ensure that local ambient conditions are taken fully into account it is good practice to hold the packer inflated for 30 minutes, which ensures a robust seal is achieved before the packer is deflated and removed from the main pipe.

The installation process ensures that, as the packer is inflated and the sock pushed against the host pipe walls, three-dimensional expansion of the seal into position is achieved, thereby giving the most effective possible.

Also, the product has been tested according to the Hamburg test where it was repeatedly exposed to a range of jetting nozzles at various pressures and flow rates. The results from this test demonstrated its robustness and confirmed its suitability as a long term product for use in renewing pipelines.

Commenting on the new arrangement Sebastian Schmitz, managing director of Fluvius, says: “The new agreement underlines the commitment of both Interflow and Fluvius to increasing demands of the global pipe rehabilitation market. We are determined to provide the global contracting sector with the latest in high-spec materials and products that are being called for by evermore demanding clients in this very competitive market in a cost effective package.”

For Interflow, Geoff Weaver, managing director, says: “Interflow has built a strong reputation for delivering, to its clients, excellent products and solutions.

“We are excited by the opportunity to enter new markets. We believe we will have a successful partnership.

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