Abstract:
A method of installing a tubular member in an inaccessible cavity includes a step of cleaning the internal wall of the cavity, a step of bringing the tubular member into contact with retaining members, and a step of fixing the tubular member by pressing it against the wall of the cavity. The method comprises three successive phases. A first phase comprises the step of cleaning the internal wall of the cavity and a step of topographically surveying the internal wall of the cavity. A second phase comprises a step of determining a position on the internal wall for retaining members for retaining the tubular member and a step of installing on the internal wall retaining members for retaining the tubular member and fixing members for fixing the retaining members to the wall. A third phase of guiding and installing the tubular member into the retaining members comprises the step of bringing the tubular member into contact with the retaining members and the step of fixing the tubular member by pressing it against the internal wall.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is based on French Patent Application No. 01 11 666 and 01 11 667 filed Sep. 10, 2001, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is hereby claimed under 35 U.S.C. §119.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the invention  
           [0003]    The present invention relates to a method of installing a tubular member, such as a pipe intended to accommodate one or more cables, in a cavity inaccessible to an operator, such as a tubular area like a network of pipes, pipelines or conduits, for example for collecting wastewater. In the tubular areas, the inaccessibility is the result of the dimensions of the cross section being too small. The invention relates more particularly to operations carried out in small-diameter (meaning in particular diameters less than 200 mm) non-pressurized underground tubular areas, such as a drain or an outlet pipe from a building, in which direct visual and material access is impossible.  
           [0004]    2. Description of the prior art  
           [0005]    A tubular member, such as a pipe intended to accommodate one or more cables, is usually installed in an inaccessible and generally tubular cavity by a method that usually includes three main phases.  
           [0006]    A first phase consists of preparing the internal wall of the cavity to receive the tubular member. This phase is primarily a phase of exploring and cleaning the walls of the cavity. The exploration can be conducted using a video camera connected to a data processing system, as described in the document FR-2 609 41 7. Cleaning a cavity with the aid of a pressurized fluid, in particular a detergent liquid, sprayed by a device that moves in the cavity is known in the art. Pressurized fluid jets can be used simultaneously to propel and stabilize the device, as described in the document FR-2 609 41 7. If the internal wall of the cavity has deteriorated, it may be necessary to fill in some depressions using mastic, as described in U.S. Pat. No. 4,782,786.  
           [0007]    The object of a second phase is to install means for retaining the tubular member in its assigned position. This is usually a system comprising retaining members distributed regularly over the wall of the cavity. The document DE-197 01 787 describes a system which is made up of members to receive the cable and fixing means for fixing these members and comprising a closed ring made of a special steel which is elastically prestressed and pressed against the wall of the tube. The document DE-198 26 880 describes a device for retaining a cable using a shape memory plastics material which adopts the shape required to press the cable against the internal wall of the cavity due to the action of heat or moisture. This technique is costly and is justified only in the case of walls that have seriously deteriorated.  
           [0008]    A third phase is the installation of a tubular member in the cavity. The tubular member is drawn in the cavity by mobile means and then installed and retained in the previously fixed retaining system.  
           [0009]    An object of the present invention is to propose a method which eliminates the drawbacks of the prior art methods of installing a tubular member in a cavity that is inaccessible to an operator, such as a pipe intended to accommodate one or more cables. In particular, the invention proposes a method that is faster, safer and less costly than the prior art methods.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention provides a method of installing a tubular member in an inaccessible cavity, which method includes a step of cleaning the internal wall of the cavity, a step of bringing the tubular member into contact with retaining members, and a step of fixing the tubular member by pressing it against the wall of the cavity, and which method comprises the following three successive phases:  
           [0011]    a first phase comprising the step of cleaning the internal wall of the cavity and a step of topographically surveying the internal wall of the cavity,  
           [0012]    a second phase comprising a step of determining a position on the internal wall for the means for retaining the tubular member and a step of installing the retaining means on the internal wall, the retaining means comprising retaining members for retaining the tubular member and fixing means for fixing the retaining members to the wall, and  
           [0013]    a third phase of guiding and installing the tubular member into the retaining means and comprising the step of bringing the tubular member into contact with the retaining members and the step of fixing the tubular member by pressing it against the internal wall.  
           [0014]    In one particular embodiment, the first phase comprises the following steps:  
           [0015]    examining the internal wall of the cavity to survey its topography,  
           [0016]    determining operations for cleaning the internal wall of the cavity to prepare it to receive the retaining means,  
           [0017]    cleaning the internal wall by means of a pressurized fluid jet, and  
           [0018]    if necessary, actuating a tool for exerting a physical action on the wall.  
           [0019]    For example, the topographical survey of the internal wall of the cavity can be effected by exploration and guidance means placed on a mobile device moving in the cavity. In the exploration mode, it can transmit data reflecting the topology of the wall of the cavity portion situated to the front of the device as it moves along to means for recording this data, such as a computer. For example, in the guidance mode, the data is viewed, for example on a screen, and the operator can therefore guide the device accurately from the outside and adapt its movement to obstacles encountered. The exploration and guidance means can be electrical but are preferably hydraulic or pneumatic. The exploration and guidance means preferably comprise an imaging device such as a video camera. In addition, illumination means can be associated with the exploration and guidance means. In the conventional way, the illumination means can comprise a light bulb connected to an electrical power supply. However, it is preferable to feed light through at least one optical fiber connected to an external light source, as this makes the operation safer by eliminating the presence of an electrical current. A data processing system can also be associated with the exploration and guidance means.  
           [0020]    The cleaning step is carried out with the aid of a pressurized fluid jet, which can also be used to propel the cleaning means. For efficient cleaning, the cleaning means can be associated with a tool capable of exerting a physical action on the wall, such as a scraper, a wire brush, an abrasion device (glasspaper) for eliminating impediments in the form of overthicknesses, or any other instrument adapted to make even and clean the internal surface of the wall of the pipeline. A tool of the above kind can be used simultaneously with the action of the pressurized fluid jets or during a subsequent pass.  
           [0021]    In another embodiment, the second phase comprises the following steps:  
           [0022]    determining a location for each of the retaining means from the topographical survey of the internal wall,  
           [0023]    preparing the locations to receive the retaining means, and  
           [0024]    fixing the retaining means at the locations using the fixing means.  
           [0025]    Locations for the retaining means are determined with the aid of a computer from data collected by the exploration and guidance means during the first phase. The locations determined in this way are then carefully degreased and dried in order not to compromise the fixing of the retaining members. The preparation of the internal wall at the locations determined in the above way can further comprise operations intended to facilitate the attachment of the fixing means, for example scoring the surface to roughen it.  
           [0026]    A first variant of the second phase comprises the following steps:  
           [0027]    determining a location for each of the retaining means from the topographical survey,  
           [0028]    preparing the locations to receive the retaining means,  
           [0029]    placing fixing means at the locations, and  
           [0030]    disposing retaining members on the fixing means, so as to fix said members to the internal wall of said cavity.  
           [0031]    A second variant of the second phase comprises the following steps:  
           [0032]    determining a location for each of the retaining means from the topographical survey,  
           [0033]    preparing the locations to receive the retaining means,  
           [0034]    placing fixing means on retaining members, and  
           [0035]    disposing the retaining members at the locations so that the fixing means are placed between the members and the internal wall of the cavity.  
           [0036]    The retaining members are components comprising a housing intended to cooperate with the tubular member. The retaining members are preferably components whose shape is adapted to the geometry of the cavity. In particular, in a pipeline also having other functions that necessitate periodic cleaning, the shape of the retaining members is adapted to resist the cleaning means usually employed. The retaining members are preferably made of a material adapted to resist attack by the environment, in particular chemical attack, such as a plastics material like PVC. The fixing means preferably take the form of an adhesive, which can be a solvent for PVC.  
           [0037]    In a further embodiment, the third phase comprises the following steps:  
           [0038]    feeding the tubular member to the location of one of the retaining members by guidance means, and  
           [0039]    pushing the tubular member toward the retaining member by means of a press until the tubular member is retained by the retaining member.  
           [0040]    The guidance means preferably further include means for identifying the vertical, for example a spirit level. The guidance means preferably comprise a gutter along which the tubular member lies. The press is preferably a hydraulic or pneumatic press.  
           [0041]    The method according to the present invention is preferably implemented using a device including hydraulic or pneumatic linear displacement propulsion means and hydraulic or pneumatic means for orienting it in space. This has the advantage that the device is able to move along a trajectory that is not strictly linear, for example to position itself relative to a wall or to circumvent an obstacle by diverting its trajectory horizontally and/or vertically.  
           [0042]    The movement of the device according to the invention in the cavity must be remote-controlled. Another advantage is the absence of electrical power for driving the propulsion means and the orientation means. On the one hand, this facilitates miniaturizing the device, which is thereby able to access tubular areas whose diameter is less than 200 mm. On the other hand, this makes the device safer to use because it employs no electrical current in an area where control is difficult.  
           [0043]    The control means preferably comprise a hydraulic or pneumatic switch, a valve and a high-pressure fluid inlet cooperating with said valve. The valve is opened and closed with the aid of a pressurized liquid in the case of a hydraulic switch or a pressurized gas in the case of a pneumatic switch. For example, the switch comprises a relatively small diameter feed tube for a fluid at a moderate pressure, communicating with the exterior. Fluid pressure is admitted into this tube from the exterior at the initiative of the operator. Opening the valve directs a high-pressure fluid jet toward the propulsion means and/or the orientation means.  
           [0044]    The orientation means preferably comprise at least one orifice on the external lateral surface of the device and communicating with the valve on the control means. The orientation means preferably comprise a plurality of orifices, which are preferably symmetrically disposed on the periphery of the device. When the corresponding valve is opened, a pressurized fluid jet escapes forcibly via the orifice, imparting movement to the device. Depending on the disposition and the orientation of the orifice, the emission of a pressurized fluid jet causes lateral movement of the device or rotation of the device in one direction or the other. The orifice is adapted to produce a fluid jet in a particular direction: horizontal, vertical or oblique, toward the right, toward the left, upward or downward. In one embodiment of the device, the orientation of the orifices can be modified while the device is operating. In another embodiment, the power of the fluid jets emitted via the orifices can be modulated.  
           [0045]    The propulsion means preferably comprise at least one main orifice disposed on the external surface of the device and communicating with a valve of the control means. The propulsion means preferably comprise a plurality of orifices disposed on the rear or front transverse surfaces of the device, in such a manner as to generate fluid jets for linear forward or reverse movement. The escaping fluid produces a sliding layer under the device, which helps to facilitate its movement. When the device according to the invention is used for cleaning a pipeline, for example, several successive passes in one direction and then in the opposite direction may be necessary.  
           [0046]    In one variant, the propulsion means further comprise at least one secondary orifice disposed on the high-pressure fluid feed tube. This produces a better distribution of propulsion force, which further improves the handling characteristics of the device.  
           [0047]    In a first embodiment, the method according to the invention uses a device further including exploration and guidance means. For example, in the exploration mode it can transmit data reflecting the topology of the location of the device to means for recording the data, such as a computer.  
           [0048]    In the guidance mode, the data is viewed, for example on a screen, and the operator can therefore guide the device accurately from the outside and adapt its movement to obstacles encountered. The exploration and guidance means can be electrical, but are preferably hydraulic or pneumatic. The exploration and guidance means preferably comprise an imaging device such as a video camera.  
           [0049]    A second embodiment of the method according to the invention uses a device further including illumination means. In the conventional way the illumination means can comprise an electric light bulb, but it is preferable to use at least one optical fiber fed by an external light source.  
           [0050]    A third embodiment of the method according to the invention uses a device further including means for identifying the vertical, for example a spirit level.  
           [0051]    The method according to the present invention can also use a device further equipped with devices providing other functions.  
           [0052]    In a fourth embodiment of the invention, in the step of the method for cleaning soiled walls of a pipeline with a view to installing a tubular member such as a pipe intended to accommodate one or more cables, the device further includes cleaning means. The cleaning means can consist in a pressurized fluid jet. For example, the pressurized fluid jet can also be used for propulsion. The cleaning means can further include a tool capable of exerting a physical action on the wall, such as a scraper, a wire brush, an abrasion device to eliminate impediments in the form of overthicknesses, or any other instrument adapted to make even and clean the internal surface of the wall of the pipeline.  
           [0053]    In a fifth embodiment, in the step of the method for installing a tubular member such as a pipe intended to accommodate one or more cables in a drain pipeline, the device further includes guidance means, for example a gutter, for guiding a tubular member.  
           [0054]    In a sixth embodiment, in the step of the method for installing a tubular member such as a pipe intended to accommodate one or more cables in a drain pipeline, the device further includes means for applying a tubular member to a wall previously equipped with retaining means. The applicator means can be a hydraulic or pneumatic press, for example.  
           [0055]    The method according to the invention is more particularly intended to be used in tubular areas having a diameter of less than 200 mm, preferably less than 150 mm, and whose diameter is preferably at least 80 mm.  
           [0056]    Other features and advantages of the present invention will become apparent in the course of the following description with reference to the accompanying drawings of embodiments provided by way of non-limiting illustrative example. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0057]    [0057]FIG. 1 represents in partial section a tubular area to be equipped and symbolizes diagrammatically the three phases of installation.  
         [0058]    [0058]FIG. 2 is a perspective view of one example of a device used to carry out the first phase.  
         [0059]    [0059]FIG. 3 is a section of one example of a device used to carry out the second phase.  
         [0060]    [0060]FIGS. 4A, 4B and  4 C are respectively side and bottom views of one embodiment of a retaining member.  
         [0061]    [0061]FIG. 5 is a perspective view of one example of a device used to carry out the third phase.  
         [0062]    [0062]FIG. 6 is a perspective view of a variant of the device from FIG. 2 incorporating secondary propulsion orifices.  
         [0063]    [0063]FIG. 7 is a section showing one embodiment of the control means of the device used to implement the method according to the invention.  
         [0064]    [0064]FIG. 8 is a functional block diagram of the control means from FIG. 7.  
         [0065]    [0065]FIG. 9 is a diagrammatic cross section showing the disposition of the pressurized fluid inlets of the control means from FIG. 7.  
         [0066]    [0066]FIGS. 10A and 10B show in section two dispositions of the pressurized fluid feeds.  
         [0067]    [0067]FIG. 11 is a diagrammatic representation of the disposition of the orifices of the orientation means of the device used to implement the method according to the invention when the latter are intended to produce lateral displacement of the device.  
         [0068]    [0068]FIG. 12 is a diagrammatic representation of the disposition of the orifices of the orientation means of the device used to implement the method according to the invention when the latter are intended to produce rotation of the device. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0069]    [0069]FIG. 1 shows in section an underground drainage pipeline  1  provided with an access orifice  2  leading to the surface of the ground  3 . The pipeline  1  includes a smaller diameter lateral conduit  4  which connects it to a building  5 . A device  6  for exploring the internal surface  7  of the conduit  4  and preparing it to receive a tubular member, as part of the first phase, is shown symbolically in the conduit  4 . The tubular member can be a tube  8  made of metal, such as stainless steel, or a plastics material, for example PVC, and which is intended to accommodate one or more cables. The device  6  is a device for cleaning the internal wall  7  using a liquid jet  9 , for example. Also represented symbolically is a device  10  for installing means for retaining the tubular member  8 , as part of the second phase. The device  10  carries a tool  11  for installing retaining members  12 , for example. Finally, there is symbolically represented a device  13  capable of guiding and installing a tubular member  8  in the third phase of the method according to the invention. The device  13  comprises a tool  14  for installing in the retaining member  12  the tubular member  8  coming from a supply  15  at the surface.  
         [0070]    The tubular member can be a pipe intended to contain optical fiber cables, for example. The devices  6 ,  10  and  13  can be propelled by a fluid pressurized in a compressor  16  and fed through a pipe  17  to the corresponding device, for example.  
         [0071]    The device  200  shown in FIG. 2 is one particular embodiment of a device  6  used in the first phase of the method. On the rear transverse surface  201  of the device  200  can be seen the propulsion means, consisting of three symmetrically disposed orifices  202 . On the lateral surface  203  are disposed orifices  204  for displacing the device  200  laterally and orifices  205  for rotating the device  200 . Pressurized fluid jets  206  are emitted via these orifices  202 ,  204  and  205  to produce a thrust which moves the device  200 . The pressurized fluid is fed from the exterior via a tube  207  connected to the rear of the device  200 . In one variant, the device  200  is generally cylindrical and further includes at the front a compartment  208  which is protected by a rounded visor  209  and accommodates an imaging device such as a video camera  210 . The visor  209  can be equipped with a cleaning system such as water jets and/or a windshield wiper, not shown.  
         [0072]    The device  300  represented in FIG. 3 is one particular embodiment of a device  10  used in the second phase of the method. In a first step, the device  300  prepares the locations at which retaining members will be fixed, as determined following the topographical survey effected during the first phase. For example, these locations are identified by an imaging device directed toward the internal wall  7 , such as a video camera  301  placed in the device  300  and protected by a port hole  302 . The device  300  also comprises a rotary device  303  carrying an abrasive tool using sand, for example, glasspaper or a wire brush. The chosen location is then cleared of dust and dried by compressed air expelled through at least one orifice  304 . The device further comprises a supply  305  of retaining members  306  communicating with a placement tool  307  via a passage  308  along which the members  306  are fed to the tool  307 . In one particular embodiment of the invention the fixing means comprise adhesive  309  contained in a pressurized tank  310  connected by at least one pipe  311  to the upper part of the tool  307 . The tool  307  is a pneumatic or hydraulic press, for example. The device  300  is propelled by the action of a pressurized fluid, in this instance preferably a gas such as air, arriving via the tube  312  communicating with the outside and connected to orifices, not shown, at the rear of the device  300 . The compressed air arriving via the tube  312  can also be fed to the orifice  304 .  
         [0073]    Once introduced into the conduit  4 , the device  300  is propelled by compressed air directed via the tube  312 , until it reaches the chosen location identified by the video camera  301  in order to fix a retaining member  306  at that location. The admission of compressed air is interrupted and the device  303  activates the tool that it carries. The abrasion can be effected dry, in which case a pulsed air jet via the orifice  304  frees the location of dust, or in the presence of water, in which case pulsed air, preferably hot air, is used to dry the chosen location. A retaining member  306  is then sent from the supply  305  to the placement tool  307 . In a first embodiment, shown in FIG. 3, adhesive  309  is deposited via the tube  311  on the surface of the member  306  that faces the internal wall  7 . The retaining member  306  is then pressed onto the internal wall  7  by the tool  307 .  
         [0074]    In another embodiment, not shown, adhesive is deposited on the wall  7  at the chosen location and a retaining member  306  is pressed onto the deposit of adhesive  309  by the tool  307 .  
         [0075]    [0075]FIGS. 4A, 4B and  4 C represent one particular embodiment of a retaining member  306 . FIG. 4A is a side view of the retaining member  306  along a longitudinal axis of the cavity corresponding to the direction of movement of the device. The retaining member  306  has a curved base  312  espousing the profile of the wall to which it is to be fixed and an elongate retaining member  313  whose section has the shape of a split ring delimiting a housing  314  into which the tubular member is to be inserted. FIG. 4B is a side view of the retaining member  306  along a transverse axis of the cavity showing its hydrodynamic shape in the direction of movement of the device. FIG. 4C is a bottom view of the retaining member  306  showing the generally oval base  312  and the retaining member  313  exposing the housing  314  for introducing the tubular member.  
         [0076]    The device  400  represented in FIG. 5 is one particular embodiment of a device  13  used in the third phase of the method. On the rear transverse surface  401  of the device  400  can be seen the propulsion means, consisting of pressurized fluid jets  402  expelled via three orifices  403  which are disposed symmetrically and connected to a tube  404  for feeding a pressurized fluid from the outside. The device  400  is provided with an imaging device  405  situated inside a compartment  406  situated at the front of the device and protected by a rounded visor  407 . A gutter  408  is formed on the device  400  to receive and guide the tubular member  8 . The interior of the device  400  is equipped with means  409  for pressing the tubular member  8  against the internal wall  7  onto which the retaining members  306  have previously been fixed. On reaching a retaining member  306 , the device  400  stops its forward movement and the tubular member  8  lying along the gutter  408  is pushed vertically upward by the means  409 , which comprise a press, for example, through an opening  410  in the bottom of the gutter  408 . The press  409  is preferably a hydraulic or pneumatic press. To improve the accuracy with which the tubular member  8  is placed, the device  400  can be equipped with a spirit level, not shown, for identifying the vertical.  
         [0077]    [0077]FIG. 6 shows a device  600  which is a variant of the device  200  from FIG. 2. Secondary orifices  602  can be provided in the manner shown in FIG. 6 to distribute the thrusts of the fluid jets used for propulsion over a portion of the length of the tube  601 .  
         [0078]    The method according to the invention is advantageously implemented by a device including control means  700  operated from the outside and whose operation is shown diagrammatically in FIGS. 7 and 8. The control means  700  for controlling the propulsion means and the orientation means of the remote-controlled device according to the invention are shown in section in FIG. 7, in which can be seen a valve  701 , one end  702  of which is connected to a high-pressure fluid inlet  703 , and the other end  704  of which directs the pressurized fluid jet toward an orifice of the propulsion means or the orientation means of the device. The valve  701  is actuated by the pressure of a fluid arriving via a control tube  705  serving as a switch. The valve  701  can include means enabling it to modulate the power of the fluid jet at the outlet from the end  704 .  
         [0079]    [0079]FIG. 8 shows control means  800  comprising a plurality of valves analogous to that from FIG. 2 and each communicating with one or more orifices corresponding to one movement. A valve P controls the propulsion means, valves RD and RG respectively control rotation of the device toward the right and toward the left, valves TD and TG control a horizontal movement enabling the device to turn toward the right or toward the left, and valves D and M control a vertical movement enabling the device to ascend or descend. Each of these valves is connected to the respective high-pressure fluid inlet  801 . The inlets  801  communicate with a common tube  802  which feeds fluid compressed to a high pressure by an external compressor  803 . Each of the valves is actuated by a fluid at a lower pressure conveyed by a control tube  804 . The switching function provided by the moderate pressure fluid feed is controlled by the operator from the outside by means of a pressure switch  805  which imposes the pressure set point corresponding to the opening or closing of each valve.  
         [0080]    The control means, the propulsion means and the orientation means of the device used in the method according to the invention use a pressurized fluid as a power supply. The propulsion fluid is fed at a high pressure such that it is possible to release a power of as much as several kW when the fluid expands to atmospheric pressure. The pressure of the fluid in the valve control tube is lower. The pressurized propulsion and orientation fluid is distributed within the device according to the invention via several inlets.  
         [0081]    [0081]FIG. 9 shows in section one arrangement of these inlets in a cylindrical compartment  900  of the device. Inlets  901  having a diameter of the order of 12 mm, for example, and disposed on a circle  902  centered on the longitudinal axis  903  of the device feed pressurized fluid via a valve to the respective propulsion orifices or orientation orifices. Tubes  904  with a smaller diameter, of the order of 1 mm to 2 mm, and disposed on a circle  905  centered on the axis  903  admit pressurized fluid actuating the valves of the control means.  
         [0082]    The inlets  901  are joined together at the rear of the device to form a single tube  906  that can be seen in FIGS. 10A and 10B. Each of the tubes  904  extends a tube  907  coming from the outside. The tubes  907  can be disposed around the larger diameter tube  906  to form a first variant  10 A of the tube  207  from FIG. 2. The tubes  907  can also be disposed inside the tube  906  to form a second variant  10 B of the tube  207  from FIG. 2. The tube  906  and the tubes  907  are preferably made from a flexible material able to follow curves resulting from the movement of the device.  
         [0083]    [0083]FIG. 11 is a cross section showing one example of the disposition of the orifices for moving the device used in the method according to the invention vertically and horizontally. Each pair of orifices producing a fluid jet in the same direction is connected to a valve corresponding to one movement. In FIG. 11, the valve TG is open and a horizontal fluid jet  110  escapes from each of the corresponding orifices  111 . Due to the action of these jets, the device turns toward the left in a horizontal plane.  
         [0084]    In a similar manner, in FIG. 12, the valve RG communicates with three orifices  120  that are disposed symmetrically and oriented at the same angle from 0° to 45° to the circumference of the device. In FIG. 12, the valve RG is open and a fluid jet  121  escapes in a vertical plane from each of the corresponding orifices  120 . Due to the action of these jets, the device rotates clockwise in a vertical plane.