Abstract:
An auxiliary tool comprises a body formed of a core material and an elastic cloth covering that covers the surface of the core material. The body is configured for insertion into a pipe ahead of a fluid used to fill the pipe so that during filling of the pipe the flow of the fluid advances the body through the pipe to force out and discharge from the pipe air existing ahead of the body while the body is advanced inside of the pipe.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an auxiliary tool for filling a pipe with water, hot water, or another such fluid without any air pockets, even when the pipe has curved parts or bent parts. The present invention also relates to a fluid injection method for injecting this fluid into a pipe. 
     2. Description of the Prior Art 
     When underground sewerage pipes and the like become aged, a pipe repair method is performed wherein the inside surfaces of the pipes are lined (Japanese Laid-open Patent Application No. 1990-194930). When the pipes are to be lined, a material impregnated with a thermosetting resin is inserted into the pipes and cured by the injection of steam, hot water, or another such heating medium. 
     However, unlike sewerage pipes, underground electric power tubes, gas pipes, industrial pipes, and other such pipes do not have a unilateral gradient, but instead have curved parts and bent parts. This leads to problems in which the cooled heating medium does not smoothly return during lining, and also problems in which air pockets form in the peaks and dips of curved pipes, and the lining material is not heated uniformly. 
     An object of the present invention is to provide an auxiliary tool for completely filling a pipe having curved parts and bent parts with fluid without any air pockets, and also to provide a fluid injection method for injecting fluid into a pipe by using this auxiliary tool. 
     SUMMARY OF THE INVENTION 
     To achieve these objects, the auxiliary tool of the present invention inserted into a pipe in order to fill the pipe with fluid is configured from a core material and an elastic cloth covering that covers the surface of the core material. 
     This auxiliary tool is shaped so as to be fitted into a pipe by selecting the dimensions of the core material and the thickness of the cloth covering. 
     In the present invention, the auxiliary tool is inserted into a pipe, and a fluid is then injected into the pipe. The auxiliary tool is constantly positioned at the head of the injected fluid, and the auxiliary tool advances forward while air in the pipe is forced out by the pressure of the injected fluid. The fluid fills the pipe without creating any air pockets in the pipe. 
     In the present invention, the use of the auxiliary tool wherein a core material is covered with an elastic cloth makes it possible to fill a pipe having a complex gradient with water, hot water, or another such fluid without creating any air pockets in the curved pipe. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view schematically showing an auxiliary tool of the present invention; 
         FIGS. 2   a - 2   b  are illustrative views showing how air pockets are formed in a pipe; and 
         FIGS. 3   a - 3   c  are illustrative views showing a state in which the auxiliary tool is used to fill the pipe with fluid when the fluid is injected into the pipe. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. The present invention allows for various other modifications, and the embodiments depicted herein are provided to describe the present invention and must not be interpreted to be limiting of the scope of the present invention. The shapes and other features of the elements in the drawings are exaggerated in order to emphasize a clearer description, and must not be interpreted to be limiting of the design and dimensions of the elements in the present invention. 
       FIG. 1  is a perspective view schematically showing an auxiliary tool  1  for filling a pipe with fluid. This pipe is an underground sewerage pipe, an electric power tube, a gas pipe, or an industrial pipe, and has curved parts and bent parts. This pipe is aged, and will therefore be repaired or rehabilitated using a tubular pipe lining material. The fluid is water or hot water, for example; and this fluid can heat and cure a thermosetting resin impregnated in the tubular pipe lining material. 
     The auxiliary tool  1  shown in  FIG. 1  is a body obtained by covering the entire external peripheral surface of a cylindrical core material  2  with a cloth covering  3 . The core material  2  retains the shape of the auxiliary tool  1 , and the cross-sectional shape thereof is substantially the same as the cross-sectional shape of a pipe that has the pipe lining material applied to the inner wall thereof. The dimension of the core material (diameter D in the case that the cross section is a circle) is preferably 60 to 98% of the nominal dimension of the pipe with the pipe lining material applied thereto. The length L of the core material  2  is not particularly limited, but is preferably 80% or more of the cross-sectional dimension. 
     The material, configuration, and other features of the core material  2  are not particularly limited. Possible examples of the material include wood, plastic, metal, and an alloy. Possible examples of the configuration include a solid block, a hollow cylinder, and a netted tube. For example, a wood block, a vinyl chloride can, a polyethylene can, an aluminum can, a stainless steel can, or the like are suitable. In cases in which the core material  2  is not solid, it is preferable that the end surface  2   a  subjected to fluid pressure at least be airtight, or an end surface that the fluid has difficulty flowing through. 
     As a modification, the core material  2  may be a cone or may have a circular base at the distal end. Furthermore, a fitting may be provided to attach a rope at both end surfaces of the core material. 
     The purpose of the cloth covering  3  that covers the core material  2  is to tightly fit the auxiliary tool  1  against the thermosetting resin impregnated tubular pipe lining material with which the pipe is rehabilitated; therefore, the cloth covering is configured from an elastic material. The thickness of the cloth covering  3  is designed to fulfill the following expression.
 
Thickness of cloth covering&lt;=(smaller than or equal to)(nominal dimension of the rehabilitated pipe−dimension of the core material)/2+Compressed amount of cloth covering
 
     The material, configuration, and other features of the cloth covering  3  are not particularly limited. Possible examples of the material for the cloth covering  3  include natural fiber, cotton, synthetic fiber, expanded rubber, expanded plastic, or the like. Suitable examples of the configuration for the cloth covering  3  include a woven fabric, a nonwoven fabric (felt), a foam, cotton, or other such materials, as well as composites thereof. 
     The method for covering the core material  2  with the cloth covering  3  is not particularly limited. Suitable examples of methods include using the elasticity of the cloth covering  3  to directly attach it to the core material  2 . The cloth covering  3  may be fused to the core material  2  by heat or bonded thereto using an adhesive. Alternatively, the cloth covering  3  can be bound around the core material  2  using bands. 
     According to the method of injecting fluid into the pipe, the auxiliary tool  1  of the present invention is inserted into the pipe through the side in which fluid is to be injected, fluid pressure is created with a pump or the like, and fluid is injected while the auxiliary tool  1  is thrust forward. 
       FIG. 2   a  shows a pipe  10  which is curved into an M shape and into which a tubular pipe lining material (not shown) impregnated with a thermosetting resin is inserted. The lining material is inserted into the pipe in an everted fashion or a pull-in fashion, and is expanded against the inner wall of the pipe  10 . The pipe  10  has two peaks  14 ,  16  from the fluid injection side  13  and is curved so that one depression  15  can be formed between the two peaks. The curves in the pipe  10  are exaggerated in the drawing for the sake of the description. 
     To cure the thermosetting resin in the pipe lining material, the fluid discharge side  17  of the pipe  10  is opened and a fluid  20  is injected through the injection side  13 . The level of fluid  20  gradually rises at the upward slope between the injection side  13  and the peak  14  of the pipe, as shown in  FIG. 2   b . When the injected fluid passes the peak  14 , fluid accumulates in the depression  15 , and the depression  15  is rapidly filled with the fluid  20 . The air between the peak  14  and the depression  15  has nowhere to escape, and an air pocket  21  is formed. 
     When fluid  20  is filled further, the level of the fluid  20  continues to rise up to the other peak  16 . When the injected fluid  20  passes the peak  16 , the fluid accumulates in the discharge side  17  at the bottom, the air between the peak  16  and the discharge side  17  has nowhere to escape, and an air pocket  22  is similarly formed near the peak  16 . Even if the fluid  20  is discharged through the discharge side  17 , the ranges of the air pockets  21 ,  22  do not change. 
     The auxiliary tool  1  in  FIG. 1  is used to prevent such air pockets from forming, as shown in  FIGS. 3   a  through  3   c.    
     The auxiliary tool  1  is made, for example, by attaching the cloth covering  3  to the core material  2 . The cloth covering  3  is composed of an elastic woven fabric having a thickness that is 20% of the inside diameter of the pipe  10  lined with a tubular lining material. The core material  2  is composed of a plastic hollow solid cylindrical body (the end surface  2   a  is hermetically sealed) having a diameter D that is 90% of the inside diameter of the lined pipe  10 . 
     The tubular lining material (not shown) with a thermosetting resin impregnated therein is inserted into the pipe  10  to be repaired and expanded against the inner wall thereof. The auxiliary tool  1  is then inserted through the injection side  13  of the pipe  10 , and the fluid  20  is injected through the injection side  13 . The auxiliary tool  1  is constantly positioned at the head of the fluid  20 , and is moved towards the discharge side  17  through the pipe  10  by the fluid pressure, as shown in  FIG. 3   a . Since the cloth covering  3  is elastic and flexible, the auxiliary tool  1  passes through the peak  14  in the pipe  10  while maintaining a tight fit against the pipe wall, and gradually continues through without slipping while forcing out air. Therefore, an air pocket  21  is not formed between the peak  14  and depression  15  as shown in  FIG. 2   b.    
     When the auxiliary tool  1  passes through the depression  15  in the pipe  10 , the auxiliary tool  1  gradually advances while forcing out air, similar to the area between the injection side  13  and the depression  15 . The auxiliary tool  1  then reaches the discharge side  17  and is discharged out, as shown in  FIG. 3   b . As a result, the pipe  10  is completely filled with the fluid  20 , as shown in  FIG. 3   c.    
     In cases in which the fluid is water, the water is continually heated and circulated, and in cases in which the fluid is hot water, the hot water is circulated, thus heating the thermosetting resin impregnated in the pipe lining material. The heating is continued for a specific amount of time to cure the thermosetting resin. The fluid  20  is then discharged out of the pipe  10 . 
     Since there are no air pockets formed in the pipe  10  when the pipe lining material is heated, the pipe lining material is uniformly heated and cured, and the pipe  10  can be lined in a superior manner.