This application relates generally to the rehabilitation of underground small diameter potable water distribution conduits as well as large diameter watermains.
Trenchless methods are known for the rehabilitation of sewer and potable water conduits. Known methods include cured-in-place-piping (CIPP) and pulled-in-place-piping (PIPP), the major difference between the two applications being internal pressure. CIPP is achieved by producing a composite tube that is inserted or inverted into a host pipe. The composite is cured inside the host pipe to activate a resin system to produce a solid composite lining inside the pipe. An example of CIPP is disclosed in U.S. Pat. No. 5,384,086, this disclosure of which is incorporated by reference herein. Another method is disclosed in Canadian Patent #2 361 960 (US 2002/0058121) entitled “A Tubular Liner and Method of Rehabilitating of Conduits”, this disclosure of which is incorporated by reference herein.
As part of what is described in the aforementioned patent, once the damaged host pipe has been lined with a pulled and cured in place liner, the service entrances become obstructed by the continuous liner. A necessary step is the opening or unplugging of service entrances to allow water to once again have its original path to flow through. It is also described in the aforementioned patent that a camera and remote-controlled drilling device are used to perform this operation.
What are not always consistent are the orientation and the degree of penetration that the service connections are tapped into the potable water conduit or watermains. A non-exhaustive list of configurations commonly seen in the industry is as follows:
Once the liner is in place and cured, a closed-circuit television “CCTV” video camera which is normally introduced into the lined potable water conduit or watermain is used to locate the service entrance valves so that they can be unplugged. This is relatively simple and straight-forward for protruding and partially-protruding service entrances. On condition that the leading face of the service entrance is far enough beyond the inner wall of the potable water conduit or watermain, typically greater than about 0.25″, the bump or pimple is sufficiently visible via video camera to allow a remote operated commercially available robot and service opening device or drill to pierce through the liner and plug found in the service entrance which was installed prior to the lining operation, thus restoring the water flow path. However, locating the service entrance valves so that they can be unplugged is not obvious for non-protruding service entrances. In these cases, it is difficult and even impossible using methods commonly known in the art to discern a bump on the liner inner surface which is otherwise generated by a protruding or partially-protruding service entrance valve.
For non-protruding service entrances, one common but costly manner to open the service entrance is to excavate a pit from street level down to the potable water conduit or watermain, disconnect the service entrance fitting, pull back the copper pipe, and open the service entrance from the outside to remove the plug and pierce through the liner using a drill and drill bit. Then, the copper pipe and service entrance fitting must be re-assembled and the excavated hole must be back-filled. Finally, asphalt, grass or other surfacing material which was originally at the street level must be replaced.
For this reason, there is a need for a method and apparatus to accurately and simply detect and locate non-protruding service entrances in order that they may be unplugged to restore water flow through the service entrance valve.
A method and system associated with the installation of tubular liners for rehabilitation of damaged underground potable water conduits and watermains. An embodiment of the invention is specifically tailored to be used in the process of lining small sized potable water distribution conduits as well as large diameter watermains and is capable of mounting on or being used in conjunction with commercially available service plugging and service opening equipment suited for such operations. Specifically, a method and system of detecting a service entrance in a conduit having a rehabilitation liner, comprises generating heat using a heat source; introducing the heat into the lined conduit; allowing the lined conduit to cool; generating a thermal image of the lined conduit using an infrared camera system; detecting temperature differentiations in the lined conduit in order to detect a service entrance wherein the service entrance is a non-protruding service entrance, a partially-protruding service entrance or a service entrance in a saddle fixed to the conduit.
It is understood that any reference and description of operations performed inside a potable water conduit or watermain is done on a given length of pipe via access pits at either extremity of the potable water conduit or watermain and that it has been previously emptied of water.
Referring to
A hot air device 15 (
In circumstances where the service entrance valve 2 is tapped in a service saddle 17 (
As indicated previously, the infrared camera 24 on its own cannot discern objects if they are all at the same temperature. Heat must be introduced in the general area where the service entrance 2 exists. This heat can be applied by various techniques as follows:
1. Hot air generated electrically within the potable water conduit or watermain 1 and directed locally in the general area of the non-protruding service entrance 6.
2. Hot air generated electrically outside of the potable water conduit or watermain 1 and directed through the potable water conduit or watermain 1 from one end and exiting the opposite end.
3. Hot air generated via a vortex tube within the potable water conduit or watermain 1 using compressed air and directed locally in the general area of the non-protruding service entrance 6.
4. Hot air generated outside of the potable water conduit or watermain 1 via a vortex tube using compressed air and directed through the potable water conduit or watermain 1 from one end and exiting the opposite end.
5. Electrical resistance heating between the potable water conduit or watermain 1, if it is electrically conductive and the service line at the curb stop or at the main waterline entrance in the house, building, or other water consuming device.
6. Back flush of cold or hot water from the house, building, or user towards the potable water conduit or watermain 1. Note here that since the service entrance 2 is plugged, water will not actually flow but will allow for a temperature difference being generated at the service entrance valve 2 if it is tapped into the potable water conduit or watermain 1.
7. Other possible sources of heat generation can be conductive, radiant, hot liquid, or other plausible heat sources.
Various materials are involved in a typical application, be it cast iron, ductile cast iron, PVC plastic, asbestos-cement, or other potable water conduit or watermain 1, the liner 10, the service entrance 2 and the service entrance 2 plug 3. Each material has specific thermal characteristics or thermal co-efficient and thus absorbs and conducts heat at a different rate. Based on this property, by injecting heat locally and homogeneously to a non-visible service entrance 2 using a hot air device 15 and then allowing it to cool down will make it such that the various components will be at different temperatures. This allows the thermal imaging system to generate an image which is clear enough to discern the center of the service entrance 2 allowing for it to be drilled from within the potable water conduit or watermain 1 by common and known methods in the art.
In order for the center of the service entrance 2 to be discerned, the invention proposes that heat be applied in the general area of the service entrance 2 causing all components to increase in temperature from their similar starting temperature. After some time of applying heat, the various components attain a new, relatively homogeneous and higher temperature at which time the heat source is turned off.
The ground around the potable water conduit or watermain 1, which is at a similar temperature to the starting temperature of the potable water conduit or watermain 1, the service entrance 2, the plug 3, and the liner 10, will act as a heat sink and draw heat from the various components. Since the various components are of differing configurations and made of differing materials, each will cool down at a different rate. The thermal imaging or infrared camera 24 will detect the various temperatures and generate an image highlighting the center of the service entrance 2. At this point, the service entrance 2 can be opened via traditional and commercially available service opening robot 5 and drill 13.
In this instance, an electrically powered hot air device 15 is mounted on the head of the service opening drill 13 which is in turn mounted on a commercially available robot 5. The electrically powered hot air device includes a heat resistant housing 18, a fan 19, and an electrical resistance beating element 20. The described assembly along with an infrared camera 24 are brought to the general vicinity of the non-protruding 6 or partially-protruding service entrance 7 whose location was coarsely measured beforehand.
Other than heating the service entrance 2 area locally from within the potable water conduit or watermain 1,
Although preferred embodiments of the invention have been described in detail herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to these embodiments and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention.
If not otherwise stated herein, any and all patents, patent publications, articles and other printed publications discussed or mentioned herein are hereby incorporated by reference as if set forth in their entirety herein.
It should be appreciated that the apparatus and methods of the invention may be configured and conducted as appropriate for any context at hand. The embodiments described above are to be considered in all respects only as illustrative and not restrictive.
This application claims the benefit under 35 U.S.C. § 119(e) of the earlier filing date of U.S. Provisional Application Serial Number 61/138,480 filed on Dec. 17, 2008, the entire disclosure of which is hereby incorporated by reference herein as if being set forth in its entirety.
Number | Date | Country | |
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61138480 | Dec 2008 | US |