Abstract:
A pipe lining material is inserted into a pipeline and expanded to press against an inner peripheral surface of the pipeline. Hot water from a first fluid source is sprayed onto the pipe lining material via a hose to cure the thermosetting resin impregnated therein and thereby cure the pipe lining material, with the sprayed hot water being accumulated in a bottom part of the pipe lining material. The hot water accumulated in the bottom part of the pipe lining material is delivered to a second fluid source separate and independent from the first fluid source, cooled in the second fluid source to provide cooling water, and supplied to the hose. The cooling water is sprayed onto the cured pipe lining material via the hose to cool the cured pipe lining material.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a pipeline lining method, and more specifically relates to a pipeline lining method for lining a pipeline in order to repair an aged pipeline. 
   2. Description of the Prior Art 
   In order to repair an aged sewer pipe or other pipeline buried under ground without removing it therefrom, pipeline lining methods have been proposed in which a tubular pipe lining material impregnated with a thermosetting resin is inserted into the pipeline, the pipe lining material is expanded by air pressure or the like and pressed against an inner peripheral surface of the pipeline, and the thermosetting resin impregnated in the pipe lining material is heated and cured to line the pipeline. To heat and cure the pipe lining material, a method is employed in which steam (water vapor) or a hot water shower is used. A heating method is also proposed in which hot water is sprayed or made into a mist, or in which the pipe is filled with hot water. 
   A method is also known from, e.g., Japanese Patent No. 2501048 in which curing is achieved by a hot water shower. In such a method, a hot water hose in which a plurality of spray openings for spraying hot water is formed at predetermined intervals in a length direction is inserted into the pipeline along with the pipe lining material, and the pipe lining material is expanded by air pressure. High-temperature hot water is then pressurized and supplied to the hot water hose while the pipe lining material is pressed against the inner peripheral surface of the pipe. Hot water is sprayed as a hot water shower from the spray openings of the hot water hose and is blown against the inner peripheral surface of the pipe lining material to heat and cure the pipe lining material. 
   Since the pipe lining material is still hot after the pipe lining material has been cured, cool water (normal temperature) is prepared by a separate water-supplying truck, and the cool water is sprayed onto the pipe lining material to cool the hot pipe lining material. 
   However, in the prior art, a water truck for supplying cool water must be provided separately from the device for supplying the hot water used to thermally cure the pipe lining material in order to cool the cured pipe lining material. A problem therefore arises in that the water truck must be transported and a parking space must be made available for the water truck. 
   Other difficulties have been encountered in the conventional methods for curing the lining material. With methods for filling the pipe with hot water, a large amount of water is required. With methods in which the hot water is sprayed in a punctual pattern, the temperature of the entire lining material is not readily controlled. Therefore, some parts of the lining material will become hot before other parts, curing will be inconsistent, and a stable quality will not be readily guaranteed. 
   Furthermore, dramatic variations occur due to pressure and hole size when hot water is sprayed, and uniform spraying is not readily achieved. 
   Therefore, it is an object of the invention to provide an inexpensive pipeline lining method that enables the pipe lining material to be uniformly heated and cured and the thermally cured pipeline lining material to be cooled at a low cost. 
   SUMMARY OF THE INVENTION 
   The present invention provides a pipeline lining method in which a tubular pipe lining material impregnated with thermosetting resin is inserted into a pipeline and the thermosetting resin therein is cured to line the pipeline. The method according to the present invention comprises the steps of inserting the pipe lining material into the pipeline and expanding it to press against an inner peripheral surface of the pipeline; spraying hot water or steam onto the pipe lining material to cure the thermosetting resin impregnated therein, the sprayed hot water or steam being accumulated in a bottom part of pipe lining material; pumping the accumulated hot water to an external location and cooling it for use as cooling water; and spraying the cooling water onto the cured pipe lining material to cool the pipe lining material. 
   In the present invention, the hot water or steam used to cure the thermosetting resin is pumped out to an external location and cooled to generate cooling water, which is then used to cool the cured pipe lining material. Therefore, a water truck for cooling need not be provided, the amount of road space used at a construction site is reduced, and the amount of water consumed by the construction project can be minimized. In addition, the high-temperature pipe lining material is cooled once the pipe lining material has been cured. Therefore, the characteristics of the cured pipe lining material can be improved. 
   Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and following detailed description of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view showing a pipeline lining method of the present invention; 
       FIG. 2  is a cross-sectional view along arrow-headed line A-A of  FIG. 1 ; 
       FIG. 3  is an enlarged top view of a steam hose and a coolant hose; 
       FIG. 4   a  is a top view showing a structure of a sprayer; 
       FIG. 4   b  is a cross-sectional view along line B-B of  FIG. 4   a;    
       FIG. 5  is a cross-sectional view corresponding to  FIG. 2  showing another embodiment of the present invention; 
       FIG. 6  is a cross-sectional view corresponding to  FIG. 2  showing yet another embodiment of the present invention; 
       FIG. 7   a  is an illustrative view showing a state in which the sprayer is mounted on a hose; 
       FIG. 7   b  is a perspective view of a fitting member of the sprayer; 
       FIG. 7   c  is a top view of the fitting member; 
       FIG. 7   d  is a side view of the fitting member; 
       FIG. 8  is a top view showing the hose on which the sprayer is mounted; and 
       FIG. 9  is an illustrative view showing a state in which hot water is sprayed from the hose. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. 
     FIG. 1  is a cross-sectional view showing a pipeline lining method. The reference symbol  1  indicates a sewer pipe or another aging pipeline buried under ground. When the pipeline is repaired, a flexible tubular pipe lining material  3  is first set at the entry of the pipeline  1  from a manhole  2  that is in communication with the pipeline  1 , and compressed air or another pressurized medium is enacted upon a pressure container  4  from an air compressor  5  via a pipe  6 . This causes the pipe lining material  3  to be turned inside out and inserted into the pipeline  1 . 
   The lining material  3  is made of a non-woven fabric composed of polyester, vinylon, acrylic, or another fiber that is sewn into a tubular shape to form a flexible tubular resin-absorbing material. The lining material  3  is impregnated with unsaturated polyester resin, vinyl ester resin, epoxy resin, or another thermosetting resin with its one surface (a surface that is the exterior surface before being everted and inserted into the pipeline  1 ) being covered by a highly airtight film. A distal end part of the lining material  3  is closed and a rear end part is open. The rear end part is coupled in airtight fashion to an open part formed on one side of a lower end part of the pressure container  4  disposed in the manhole  2 . 
   Water supplied from a water tank  9  is softened by a water softening machine  10  and then supplied to a steam tank  13 . A heater (not shown) is used to heat the steam tank  13  to make hot water  18 , which-boils to generate steam  20 . A steam pump  15  is connected to an upper part of the steam tank  13  via a pipe  14 . Steam is fed through a steam hose  16  via the steam pump  15 . The steam hose  16  is coupled to a distal end part of the pipe lining material  3  using a rope  17 , and inserted into the pipeline  1  as the pipe lining material  3  is being everted and inserted. 
   A distal end part of a coolant hose  30  shown in  FIGS. 2 and 3  (but not in  FIG. 1 ) is also coupled with a distal end part of the lining material  3  using the rope  17  in the same manner as with the steam hose  16 . The coolant hose  30  is accordingly inserted into the pipeline  1  along with the steam hose  16  as the pipe lining material  3  is being everted and inserted. The coolant hose  30  is disposed alongside the steam hose  16  at a distance d, as shown in  FIGS. 2 and 3 . 
   Cooling water (normal-temperature water) is supplied via a pump  41  to the coolant hose  30  from a water tank  40  cooled by a cooling device  43 , as shown in  FIG. 2 . The hot water  18  that accumulates in a lower part of the pipe lining material  3  is pumped out by a pump  42  and supplied to the water tank  40 . 
   The portions of the pressure container  4  through which the steam hose  16  and coolant hose  30  are inserted are kept airtight by, e.g., a gasket (not shown). 
   A plurality of sprayers  19  is provided to the steam hose  16  as spraying means at equal intervals in a length direction of the hose, as shown in  FIG. 3 . As shown in  FIGS. 4   a  and  4   b , the sprayers  19  have two nozzles  19   a . Steam sprayed from nozzle holes  19   c  in the nozzles is diffused by a diffusing member  19   b  and sprayed as steam mist  20   a . In the present invention, the term “steam mist” refers to a mixture composed of the steam and a plurality of small water drops (mist) in the form of a mist resulting from the condensed steam. 
   Sprayers  31  having the same configuration as the sprayers  19  are provided to the coolant hose  30 . Cooling water is sprayed in the form of a mist from the coolant hose  30  via the sprayers  31 . A plurality of the sprayers  31  of the coolant hose  30  is disposed at the same positions in the length direction of the hose as the sprayers  19  and at the same intervals as the sprayers  19 . 
   A configuration may also be adopted in which the diffusing members  19   b  of the sprayers  19 ,  31  are omitted. The sprayers  19 ,  31  may also be provided to a lower side as indicated by a broken line in  FIG. 3 , and provided to left and right sides as well. 
   Before the everted and inserted pipe lining material  3  is heated and cured, compressed air is applied via the air compressor  5 , and the pipe lining material  3  is made to expand and press against the inner peripheral surface of the pipeline  1 . In this state, the steam tank  13  is heated to generate steam  20 , and the steam pump  15  is driven to supply the steam  20  under pressure to the steam hose  16 . As shown in  FIG. 2 , the steam  20  is uniformly diffused in all directions around a perpendicular direction y 1 , sprayed from the sprayers  19  as the steam mist  20   a , and blown against the inner peripheral surface of the pipe lining material  3 , thus heating the pipe lining material  3 . 
   When the steam mist is at a high temperature and is blown directly against the pipe lining material, a risk may arise that the characteristics of the pipe lining material will deteriorate, depending on the type of pipe lining material. Therefore, the steam mist is cooled, which reduces the temperature of the steam mist when blown against the pipe lining material. 
   The cooling water is sprayed from the sprayers  31  of the coolant hose  30  toward the pipe lining material  3  in order to cool the steam mist effectively. A spraying direction y 2  is inclined an angle a from the direction y 1  (perpendicular direction) in which the steam mist is sprayed from the steam hose  16  toward the pipe lining material  3 . The lines y 1  and y 2  are set so as to intersect substantially at the inner surface of the pipe lining material  3 . The spraying direction y 2  of the cooling water from the sprayers  31  is thus inclined from the spraying direction y 1  of the steam mist from the sprayers  19  of the steam hose  16 . This allows the steam mist to be uniformly cooled by the cooling water sprayed from the sprayers  31 . 
   The cooling water supplied from the coolant hose  30  is used to cool the steam mist or, as described below, to cool the cured pipe lining material. The cooling water is intended to be about ambient temperature (about 20° C.) or an otherwise normal temperature below ambient temperature. 
   The pipeline  1  is thus lined as a result of the curing of the thermosetting resin impregnated in the pipe lining material  3  heated by the cooled steam mist. 
   After the pipe lining material  3  has been cured, the heating of the steam tank  13  and the driving of the pump  15  are stopped, but the pumps  41 ,  42  continue to be driven to circulate via the water tank  40  the hot water  18  that has accumulated in the bottom part of the pipe lining material  3 . The water tank  40  is cooled by the cooling device  43 . The hot water  18 , which has a temperature of about 70 to 80° C., becomes normal-temperature cooling water having a temperature of 20° C. or less, and is sprayed in the form of a mist onto the cured pipe lining material  3  via the sprayers  31  of the coolant hose  30 . Accordingly, the pipe lining material  3  is effectively cooled, and the strength of the pipe lining material  3  can be improved. 
   In the prior art, a water truck for cooling must be provided in order to cool the cured pipe lining material. However, in the present invention, the equipment for cooling the steam mist requires no additional apparatus. Therefore, the water truck for cooling does not need to be provided, the amount of road space used at a construction site is reduced, and the amount of water consumed by the construction project can be minimized. 
   In the above-described embodiment, a configuration may be adopted in which the hot water  18  that has collected at the bottom part of the pipe lining material  3  is returned to the steam tank  13  via a pump (not shown), and the hot water used for the steam is circulated. 
   In the above-described embodiment, the steam mist sprayed from the steam hose  16  is actively cooled. However, the characteristics of some pipe lining materials do not require cooling to be performed. When such a pipe lining material is used, a configuration may be adopted in which a single hose is used as a steam/coolant hose, the steam mist is sprayed via the hose when the pipe lining material is to be cured, and the cooling water is sprayed via the same hose when the cured pipe lining material is cooled. 
     FIG. 5  shows such an embodiment in which a steam/coolant hose  50  is provided instead of the steam hose  16 . The structure of this hose is similar to that of the steam hose  16 . A plurality of sprayers similar to the sprayers  19  is provided to the hose  50 . 
   When the pipe lining material  3  is to be cured, a switching valve  51  is switched to a steam side and steam from the steam tank  13  is supplied to the hose  50  and sprayed as steam mist from the sprayers provided to the hose  50  to heat and cure the thermosetting resin in the pipe lining material  3 . After the pipe lining material  3  has been cured, the switching valve  51  is switched to a cooling water side and cooling water is supplied from the water tank  40  to the hose  50  and sprayed in the form of a mist from the sprayers provided to the hose to thereby cool the cured pipe lining material  3 . 
   The same effect can be obtained in this embodiment as in the first described embodiment. 
   The pipe lining material  3  can also be cured by high-temperature hot water instead of steam. For example, as shown in  FIG. 6 , the water tank  40  is heated by a boiler  62 , and high-temperature hot water is supplied to a hot water/coolant hose  60  via a hot water pump  61 . The hot water/coolant hose  60  has a configuration similar to those of the steam hose  16  and the steam/coolant hose  50 . The hot water becomes hot water mist and is sprayed onto the pipe lining material  3  from sprayers of the hot water/coolant hose  60 . This causes the pipe lining material  3  to be heated and cured. 
   After the pipe lining material  3  has been cured, the operation of the boiler  62  is suspended, and the cooling device  43  is driven to cool the hot water  18  supplied from the pump  42 . The hot water, which has now become cooling water, is then supplied to the hose  60  via the hot water pump  61 . The cooling water is sprayed in the form of a mist from the sprayers of the hose  60  to cool the cured pipe lining material  3 . The same effect can also be obtained in this embodiment as in the embodiments as mentioned above. 
     FIGS. 7 and 8  show another embodiment of a sprayer  70  (spray system) for uniformly spraying hot water to uniformly heat and cure the entire pipe lining material. The sprayer  70  comprises a nozzle unit  71  and a fitting member  72  that fits into the nozzle unit  71 , as shown in  FIG. 7   a . The nozzle unit  71  has a conical nozzle opening  71   a , a cylinder part  71   b  that communicates with the nozzle opening, curved parts  71   d ,  71   e  that expand on either side, and a fitting part  71   c  formed below the nozzle opening  71   a . The cylindrical fitting member  72  shown in  FIGS. 7   b  through  7   d  fits into the fitting part  71   c . Longitudinal grooves  72   a ,  72   b  that extend in a perpendicular direction are formed on the fitting member  72  at positions facing a radial direction. The longitudinal grooves  72   a ,  72   b  pass through a cylindrical groove  72   e  positioned below a central part of the nozzle unit  71  via transverse grooves  72   c ,  72   d . Elastic mounting fixtures  73 ,  74  are fitted into the curved parts  71   d ,  71   e  of the nozzle unit  71 . Distal ends  73   a ,  74   a  of the mounting fixtures are bent downward. 
   The sprayer  70 , which has the fitting member  72  fitted into the nozzle unit  71 , can thus be used for the sprayers  19  ( 31 ) of the embodiments as mentioned above.  FIG. 7   a  shows a state in which the sprayer  70  has been attached to the hot water/coolant hose  60  in  FIG. 6 . The nozzle unit  71  of the sprayer  70  is passed through an open part  60   a  of the hot water/coolant hose  60 , and the hot water/coolant hose  60  is firmly held between the curved parts  71   d ,  71   e  and the distal ends  73   a ,  74   a  of the fixtures  73 ,  74  via a ring-shaped fixture  75 . This allows the sprayer  70  to be attached to the hot water/coolant hose  60 . A state in which the sprayer  70  is mounted on the hot water/coolant hose  60  is shown as a top view in  FIG. 8 . 
   The nozzle unit  71  and fitting member  72  of the sprayer  70  are both made of, e.g., a resin, metal, ceramic, or wood. In the examples shown in the drawings, only two longitudinal grooves are provided. However, more than two longitudinal grooves may be formed on the periphery of the fitting member. 
   How the sprayer  70  works in such a configuration will be described based on the embodiment in  FIG. 6 . The water tank  40  is heated by the boiler  62 , and high-temperature hot water is supplied to the hot water/coolant hose  60  via the hot water pump  61 . The hot water ascends perpendicularly through the longitudinal grooves  72   a ,  72   b  of the fitting member  72  of the sprayer  70 , passes through the transverse grooves  72   c ,  72   d , converges in the cylindrical groove  72   e , and is sprayed upward via the nozzle opening  71   a  of the nozzle unit  71 , as indicated by the dotted/dashed line in  FIGS. 7   a  and  7   b . The spray state is shown in  FIG. 9 . The hot water is uniformly sprayed from the hot water/coolant hose  60  in all directions, enabling the entire pipe lining material  3  to be uniformly heated and the thermosetting resin impregnated in the pipe lining material  3  to be cured. 
   After the pipe lining material  3  has been cured, the operation of the boiler  62  is suspended, and the cooling device  43  is driven to cool the hot water  18  supplied from the pump  42 . The hot water, which has now become cooling water, is then supplied to the hose  60  via the hot water pump  61 , and is sprayed from the sprayer  70 . The cooling water is also uniformly sprayed in all directions in the same manner in which the hot water was sprayed, thereby allowing the entire pipe lining material  3  to be uniformly cooled to a normal temperature. 
   In this configuration, the hot water, which is sprayed uniformly in a wider range, is used to heat and cure the pipe lining material in a uniform manner. Accordingly, stable quality can be ensured without any incidence of inconsistent curing. Furthermore, the time required for curing can be reduced, and the amount of water can be reduced by about half or more. 
   Cooling the thermally cured pipe lining material in steps rather than in a rapid process enables more stable quality to be ensured without any risk of diminished strength. 
   The cooling water truck needed in the prior art is rendered unnecessary. The amount of water used at the construction site can be reduced, the initial arrangements associated therewith need not be performed, and the time required for the construction project can be reduced. In addition, a water truck (water supply tank) for cooling is rendered unnecessary. This allows the amount of road space used at a construction site to be reduced and traffic congestion and the like to be avoided.