Methods of renovating sewers

A method of relining a sewer having a lateral connected therewith which comprises:

• inserting lengths of pipe liner into the sewer;
• locating the approximate position of the lateral when the distance between the edge of the last pipe liner is less than the length of a length of pipe liner so that the lateral will meet the sewer at a position lined by the next pipe liner;
• locating the radial and longitudinal position of the lateral with respect to a reference point on the trailing edge of the last pipe lining;
• at the control station, cutting a hole in the next length of pipe liner in the same relative radial and longitudinal position with respect to a reference point on the leading edge of the next pipe liner;
• passing the next pipe liner along the sewer to the jointing position with the last pipe liner;
• and aligning the reference point on the next pipe liner with the reference point on the last pipe liner whereby the hole in the next pipe liner is aligned with the lateral.

A method of controlling the relining of a sewer from a fixed control station above the ground adjacent a first manhole, the sewer having a plurality of sewer laterals, the method comprising passing lengths of pipe liner down the first manhole and along the sewer by inserting into each pipe liner an inflatable bag, the bag when inflated gripping the sides of the pipe liner, the bag including along its length close to its edge a cylindrical slot through which a winch cable is inserted, the winch cable extending from the first manhole to a second manhole, a first length of pipe liner being passed along the sewer from the control station to a predetermined starting position, the bag within the pipe liner deflated and removed from the sewer leaving the pipe liner in position, a grouting pump for producing grout in situ being attached to a nipple in the pipe liner, the pump being controlled from the control station to produce grout and feed it through the nipple to fill the annular space between the pipe liner and the sewer, breaking the connection of the pump to the nipple and removing the pump from the sewer, subsequently repeating the steps of passing a further length of pipe liner along the sewer from the control station to a jointing position wherein the further length of pipe liner abuts the sewer lining, and forming a permanent joint between the further length of pipe liner and the lining the extend the sewer liner, the pipe liners being thermoplastic and wherein each length of pipe liner includes at one of its ends a spigot and at its other end a socket, the spigot of a a first pipe liner being a slidable fit into a socket of an adjacent pipe liner, the socket including on its inner surface an electrically conductive strip extending circumferentially around the pipe liner, and wherein each further length of pipe liner is passed along the sewer until the spigot of the further pipe liner lies within the socket of the adjacent end of the lining with the conductive strip lying between the lining and the further length of pipe liner, the joint being effected by inducing a current in the strip to cause fusion welding of the further length of pipe liner to the lining, the induction being controlled at the control station, each further length of pipe liner being passed along the sewer with an induction coil located within the pipe liner, at a position aligned with the spigot of the pipe liner, the coil beiing connected to a power source and a volt meter at the control station, current being passed through the coil while the pipe liner is passed along the sewer, so that when the spigot of the further length of pipe liner is within the socket of the lining the voltage across the coil changes, whereby the volt meter deflects to provide an indication at the control station that the further length of pipe liner is in the joint position where the joint may be effected, the induction coil being removable from the sewer to the control station once the joint has been completed, the annular space between the lining and the sewer being filled with grout using a grouting pump, the steps being repeated until the distance between the edge of the lining and the approximate position of a lateral is less than the length of a length of pipe liner such that the position lined by the next length of pipe liner is the position at which the lateral will meet the sewer, a hole then being cut into the next length of pipe liner at the exact position of the lateral by the steps of locating the radial and longitudinal position of the lateral with respect to a reference point on the edge of the sewer lining, at the control station cutting a hole in the next length of pipe liner the same radial and longitudinal position with respect to a reference point on the length of pipe liner, passing the next length of pipe liner along the sewer to the jointing position, and aligning the reference point on the length of pipe liner with the reference point on the lining whereby the hole in the pipe liner is aligned with the lateral, the cylindrical slot through which the winch cable passes forming the reference point, the cut pipe liner being passed along the sewer with a closed circuit television camera facing out of the hole, the camera being connected to the control station so that from the control station it may be checked that the hole is exactly aligned with the lateral before a joint is effected between the cut pipe liner and the lining, the annulus around the cut pipe liner then being grouted by passing an auxiliary grouting bag along the sewer to a position within the cut pipe liner, the auxiliary grouting bag comprising a first flexible cylindrical bag having a hole in its side of generally elliptical shape around which is fixed a flexible shuttering bag, the shuttering bag being capable of being in two positions, a first position wherein the shuttering bag is totally enclosed within the cylinder, the cylindrical bag being placed within the cut pipe liner with the hole of the bag and the pipe generally aligned, pressure being applied from the control station to the shuttering bag from its first position to its second position in which it protrudes out of the cylinder into the lateral whereby the lateral is completely sealed off so that the annulus between the cut pipe liner and the sewer may be grouted, the cycle of steps then being repeated until the next lateral position, all operations being effected and controlled from the control station.