Trenchless pipeline repairs

The technology of repairing with GRP (glass reinforced plastic) panels is used with all conduit cross-sections – round, ovoid, square and bell-shaped sewers. The material of which the sewer was originally made from is insignificant, therefore it is possible to use GRP panels with all material types. The method involves fitting panels made of resin, glass fibre and silica sand composite inside a sewer. This combination forms a new self-supporting pipe. The GRP pipes guarantee the full restoration of the mechanical strength in the repaired sewer. In spite of the narrowed diameter of the sewer under repair, its hydraulic flow capacity is not reduced because the units possess high internal surface smoothness.
Installation of the GRP units involves pulling them into the old sewer. The dimensions of the unit, including panel thickness, shape and length are determined individually for each conduit, which is to be repaired. As soon as the panels are installed inside the sewer section, free spaces between the sewer wall and panels are filled with foam-concrete possessing adequate technical parameters.

Application range:

  • all types of sewerage systems (sanitary, storm water drainage, industrial),
  • sewers – round, ovoid, bell-shaped and other,
  • for each type of repaired conduit material

Repair with glass sleeve

The sleeve technology is used for trenchless repairs of sewerage systems consisting of the following conduits: stoneware, concrete, reinforced concrete, cast iron, steel and plastic.

The basic component of the kit is an elastic sleeve made of glass fibre, impregnated with resins: polyester or vinyl, secured with polyester foil inside and outside. The sewer is repaired by covering the inside with a lining formed by the stretched sleeve which matches the shape of sewer under repair. The hardened lining works as a new sewer, fixes cracks, fills small holes in the sewer, seals it and prevents the infiltration of water and exfiltration of sewage. The glass fibre method is designed for repairing sewers with diameters ranging from 150mm to 1600mm. Within the above range of diameters it is also possible to obtain sleeves matching the actual inner dimension of a conduit which is different from the diameters in the specified series of types. Depending on the aggressiveness of the sewage, sleeves are impregnated with polyester or vinyl ester resin.

The sleeve is installed from wells accessible in the collector, and thus no starting trenches are required. In order to ensure correct progress of installation works in a sanitary sewage system, storm water drainage or combined sewer system in the case of a high inflow of sewage or rain water, the sections under repair should be plugged with pneumatic plugs and water/sewage should be pumped to further network sections.

Sleeve insertion – in order to ensure the proper sliding of a sleeve during insertion it is necessary to pull a strip of PVC foil of an adequate width into the sewer section under repair (system foil, width dependent on the diameter of the pipeline being repaired). Then, a steel cord is inserted, to which one end of the sleeve, which has a special terminal, is hooked. A flat sleeve (not adhering to the inner surface of the conduit) is inserted along the entire length of section under repair, using a pulling machine.

After the cord is released, process conduits are connected to both sleeve ends. On one side it is a conduit connected to the control unit supplying compressed air, and the UV device.

As soon as these preparations are complete, the sleeve is filled with compressed air until a specified pressure is reached (ca. 0.5 bar). The sleeve tightly adheres to the sewer walls and forms an inner lining. In order to cure the lining, a chain of UV lamps is pulled through the lined pipeline. The lamps are operated from a control panel. While the UV lamps are moving, the sleeve is cured (the speed at which the chain of lamps moves depends on the thickness of the wall). The UV technology allows up to 300 metres of a pipeline to be repaired at a time.
After the disconnection of the process conduits, the ends of the cured lining are opened, and protruding ends are trimmed in line with the end of the conduit, bevelled and secured with sealing putty.
After check tests (leak proof test and the evaluation of the condition of the internal surface, carried out using a TV camera), the sewer is ready to work on.