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Joint Sealing

The testing and sealing of defective pipe joints with a grout using a packer, all activities being from a single process.

A common method of sealing leaking joints in gravity pipelines is to use a packer, which combines the functions of leak testing and grout injection. Joint testing and sealing may or may not be 'localised', depending on how many joints fail.

 

A packer with inflatable end elements is positioned across a pipe joint and pressurised to isolate the joint. Air or water pressure is then applied to the centre section of the packer and the rate of pressure loss through the joint is measured. If the loss exceeds a specified limit, a sealing resin compound is injected into the joint through the packer and the joint is re-tested.

 

The packer design varies, using either a two-part acrylic grout or a water-active polyurethane resin. The grout combines with the ground around the leaking joint to form an impermeable mass, preventing leaks and enhancing structural stability.

Polyurethane grouts are hydrophobic and react either with free water in the soil or with a water solution injected through the packer at the same time as the grout. Generally, a ratio of 1 part grout to 8 parts water is recommended for pipe sealing, variations creating products of different strengths.

Last Updated on Thursday, 25 April 2013 16:34

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