Process and device for rehabilitating pipes

Hydraulic and earth engineering – Subterranean or submarine pipe or cable laying – retrieving,... – Repair – replacement – or improvement

Reexamination Certificate

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Details

C138S098000

Reexamination Certificate

active

06270289

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for rehabilitating pipes, preferably an underground sewer line, by means of a resin-saturated hose assembly made of fibers, felt or a woven material which is drawn into the pipe through a shaft above the ground to the pipe and, by means of a pressure medium, is pressed against the interior wall of the underground pipe. The pressure medium is heated and the hose assembly is subject to the pressure and heat load until the resin hardens.
The invention also relates to a device for carrying out the rehabilitation process.
2. Description of the Related Art
A process of the initially mentioned type is known wherein a lining hose, produced from a needled felt, from fibers or from a woven material and provided on the outside and/or the inside with a layer which is impermeable to liquid, is saturated at the factory with resin and is transported in a refrigerated car to the location where it is used. After the underground pipe to be rehabilitated has been cleaned, the lining hose is drawn into the underground pipe through a shaft. An inversion pipe is placed into the shaft which protrudes from the upper shaft opening. At the upper edge of the inversion pipe, one end of a calibration hose is secured while at the lower end of the inversion pipe one end of the lining hose is secured. Under the influence of a pressure medium, preferably water, the calibration hose is inverted into the lining hose. The calibration hose, which is moved through the lining hose under the pressure of the water, enlarges the lining hose and presses it against the interior wall of the underground pipe. At the free front end, i.e., at the inside of the calibration hose, a perforated heating hose is attached which during the inversion of the calibration hose is guided into the lining hose together with the calibration hose. Through the heating hose, heated water or water vapor is then supplied from the outside while water is suctioned off from the lower area of the inversion pipe, so that the filling level of the described system accommodating the pressure medium remains constant.
With the known process, only the resin saturation process of the lining hose is undertaken above ground, wherein said hose is transported in a refrigerator car to the site of installation.
SUMMARY OF THE INVENTION
The invention is based on the task of creating a process of the initially mentioned type in such a way that, through the expansion of the extent of prefabrication undertaken above ground, preferably at the location of impregnation, the working steps and the possible sources of errors are reduced during the installation on-site and in that way, the quality of the completed lining is increased and made uniform.
According to the invention, this task is solved in that one hose is inverted into another by means of compressed air above ground. This hose assembly has an impermeable layer on the outside and the inside and at least one layer in the center which is saturated with resin. The hose assembly is closed at both ends by means of connection heads having a passage. The hose assembly is pulled via a shaft into the underground pipe. A heatable pressure medium is applied through the connection heads in a closed cycle and presses the hose assembly against the interior wall of the pipe to be rehabilitated, and maintains this position until the resin hardens, while the pressure medium flows in one direction through the hose assembly across the entire cross-section during the hardening process.
With the process of the invention, the heated pressure medium, circulating in a cycle, can be guided through several hose assemblies drawn into pipes, wherein the hose assemblies are connected by means of hoses or lines.
In contrast to the described known process, a prefabricated hose system with a heating medium will be set within the flow of the passage. The hose system thereby becomes a component of the entire heating cycle. In contrast to the process so far, wherein the heating medium circulates in the hose system only, this leads to a better heat distribution, relative to the cross section of the pipe, and to a better controllable (adjustable) heating and cooling curve and possibly also to a clear reduction of the heating and cooling times. The establishment of the hose assembly at the factory results in improved quality control.
Since the pressure medium is in a closed system, no pressure fluctuations occur. Furthermore, an improved compaction is achieved. Several pipes can be rehabilitated simultaneously. The old pipeline can be set horizontally or laterally.
In one embodiment of the process, the heated pressure medium is guided exclusively in a closed system during the time needed for hardening the resin. The pump, provided in the closed system, and the heat exchanger may be uncoupled and the ends of the pipelines or the hoses containing the pressure medium may be shut off by means of shutoff members. The shut-off is opened at the end of the subsequent cooling period and the pressure medium is then drawn off. Furthermore, the connection heads at the ends of the lining hose are removed. In order to prevent negative pressure, a safety valve may be provided.
The device for carrying out the process has a pressure chamber, arranged above ground and operated by compressed air, which is provided with a connecting piece for securing one end of the lining hose and the calibration hose, which can be inverted into the lining hose, or the tubular film and the lining hose, which can be inverted into the tubular film. One or several lining hoses, which have been drawn into old pipeline, form a part or parts of a closed hose or pipeline system in which at least one pump and at least one heating arrangement are provided for the pressure medium guided through the system.
Additional characteristics of the invention result from the claims.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the claimed invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.


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