The PI.TRON procedure has proven itself in the rehabilitation of domestic connections with a shuttering that can be connected to the filling robot. Sewer maintenance providers can thereby satisfy the legal requirements existing in many places for long-lasting tightness of connections between main sewer channels and domestic connections – in other words, there is no discharge of waste water into the groundwater (exfiltration) or entry of groundwater into the sewer.

If no liner is fed into the sewer, after completing the milling work and removing the milling mud, the robot travels with the shuttering cuff and a plastic shuttering to the affected domestic connection and positions a rubber sealing bag there to shut off the inflow. Using two sliders, an epoxy resin is pressed into the hollow space created behind the shuttering. A plunger presses the epoxy resin into the damaged area through a tube using compressed air. After a few hours of curing the connection is durably leak-proof. About 500,000 domestic connections around the world have been sealed using this procedure.

The following work steps are necessary for sealing domestic connections in the main sewer:
1. General preliminary work (milling work, measuring the connections being rehabilitated to prevent faulty drilling later on when opening the liner)
2. Opening the inliner with the milling robot
3. Adequately deep milling of the soiled connections using the robot Grinding the liner edge
5. Relief milling the liner
6. Cleaning the adhesive surface
7. Setting the shuttering cuff and the rubber sealing bag
8. Filling/grouting the shuttered cavity behind the sleeve with epoxy resin
9. Removal of the shuttering cuff and the sealing bag from the sewer

After high-pressure cleaning of the damaged section, the area being rehabilitated is milled out sufficiently deep in accordance with the material manufacturer's guidelines. After the milling mud has been removed, the shuttered damaged area is grouted/filled in accordance with manufacturer specifications. Finally, the formwork is removed and any post treatment can be carried out, if necessary. Rehabilitation with sleeve shuttering is possible with a groundwater level of up to 1.5 m, depending on the existing conditions.

After the necessary preparatory work has been performed, like the removal of deposits, the sewer robot mills out the existing crack in a trapezoidal shape to a sufficient depth with the aid of a groove cutter. The residual milling mud is then removed with the water jet technology on the robot or with a different rinsing vehicle. The filling robot then fills the grooves in the area of the crack with epoxy resin. Depending on the damaged area various filling tools or crack shuttering can be utilised. After the epoxy has cured, any existing burrs or uneven surfaces are removed using tools (e.g. a wire brush) that do not damage the enamel of the pipe.

Repairing holes or sealing lateral inflows is performed using the same procedure as the crack repair described above. However, particular attention must be paid to the following difference: The frontal sides of the pipe wall are milled out at full power until the loose and/or soiled parts of the pipe material have been removed. Foreign objects that jut out in the cross-section of the outside diameter of the pipe must be milled back sufficiently deep. Holes with a large diameter should generally be worked on with shuttering that is considerably larger than the damaged area and that have a curvature that corresponds to the nominal width of the pipe.