Pipe Inverts

It is a routine part of drain system maintenance nowadays to carry out TV surveys at regular intervals. More and more instances of damage to pipes come to light, especially affecting inverts. The causes of damage are various. Sometimes the gradient is so steep that friction has destroyed the invert over the course of time; or the sewage being carried may be aggressive. The later is a common phenomenon, and not only in the vicinity of galvanising facilities, dairies, breweries or wineries. Standard concrete cannot withstand such attack. In many cases, only the invert is attacked. Damaged pipe inverts can be very quickly, efficiently and permanently renovated with ERGELIT-dry mortar KS. Often, too, repairing the invert can be the preparatory stage to renovating the pipe by the spraylining technique or by hoselining.Procedure:The invert area of the pipe is first thoroughly cleaned using a high-pressure jet. All deposits, loose pieces and particularly greasy or synthetic build-up must be removed. In case the normal working pressure of a pipe cleaning trolley is not adequate, we recommend switching to a high pressure jetting system or sand-blasting.

After thorough cleaning of the pipe, the lateral connections are made watertight. This can be achieved from the inspection chamber on the property, or from the mains. If the main pipe has been drained, it is recommended to carry out another quick clean-up in the direction of flow. In this way, dirt residues and small amounts of water coming from holes that may be present, are removed. For subsequent mortar-based repair of the defective invert, ERGELIT-KS 1 or ERGELIT-KS 2 are made up with water on site.

In the case of smaller quantities, it is sufficient to pour the ERGELIT fresh mortar ahead of a squeegee. The squeegee, which is adapted to fit the diameter of the pipe exactly, is then pulled through the pipe. The mortar is thus spread along the pipe and forced into the holes in the invert. This procedure is repeated several times if necessary, until all gaps and holes in the invert have been filled.

For heavier instances of damage which require the use of larger quantities of mortar, the use of a mortar pump is recommended. The mortar is then pumped through a hose ahead of the squeegee. By using a TV camera at the end of the hose, the amount of mortar needed can be constantly monitored and pumped down the hose as required. In order not to put at risk lateral connections lying in the Kempfer area or level with the invert, it is essential to carry out invert relining only with the aid of a TV camera.

Thanks to the rapid hydration properties of ERGELIT-KS, the pipe can de put back into service again within 4 hours after invert relining has been completed. As has often been conclusively demonstrated, the conduit is now watertight and can resume its proper function for many years. An outstanding feature of ERGELIT-KS 1 and KS 2 is their high resistance to corrosion. (See technical sheet.) Thanks to this, the newly relined invert has a life expectancy many times longer than the original concrete pipe.