Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-10-21
2001-07-03
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S092000, C156S093000, C156S094000, C156S148000, C138S097000
Reexamination Certificate
active
06254709
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a pipe liner bag for use in repair of an old pipe.
2. Description of the Related Art
When an underground pipe, such as pipelines and passageways, becomes defective or too old to perform properly, the pipe is repaired and rehabilitated without digging the earth to expose the pipe and disassembling the sections of the pipe. This non-digging method of repairing an underground pipe has been known and practiced commonly in the field of civil engineering. The pipe lining method utilizes a tubular pipe liner bag made of a resin absorbent material impregnated with a hardenable resin, and having the outer surface covered with a highly air-tight plastic film. The tubular pipe liner bag is inserted into a pipe to be repaired by means of a pressurized fluid such that the pipe liner bag is turned inside out as it proceeds deeper in the pipe. Hereinafter, this manner of insertion shall be called “everting”. When the entire length of the tubular liner bag is everted (i.e., turned inside out) into the pipe, the everted tubular liner is pressed against the inner wall of the pipe by a pressurized fluid, and the tubular flexible liner is hardened as the hardenable resin impregnated in the liner is heated, which is effected by heating the fluid filling the tubular liner bag. It is thus possible to line the inner wall of the defective or old pipe with a rigid liner without digging the ground and disassembling the pipe sections.
The pipe lining material for use in the foregoing pipe lining method may be manufactured by a method proposed, for example, in Japanese Patent Publication No. 58-33098. Specifically, this method involves abutting both side ends of a strip-shaped resin absorbent material in the width direction, and joining, by lock sewing or zigzag chain sewing, the abutted ends of the strip-shaped resin absorbent material to form a tubular resin absorbent material.
However, the lock sewing or zigzag chain sewing, employed in the conventional manufacturing method, is late in sewing, as compared with straight sewing such as final sewing or through sewing. In addition, since a sewing yarn appears on the surface of a sewed material over a constant width, the sealability cannot be ensured for the joint unless any processing is added thereto. Such sealing processing causes an increased complexity of the manufacturing method.
A pipe liner bag is inflated within a pipe line by the action of a fluid pressure and pressed onto the inner wall of the pipe line. To prevent the pipe liner bag from wrinkling, the pipe liner bag is typically manufactured to have a smaller diameter than that of an intended pipe line. Thus, if the pipe liner bag extended by a fluid pressure is applied with a tension, the sewed portion is extended and reduced in thickness, resulting in an insufficient strength. It is therefore necessary to reinforce the sewed portion of the tubular pipe liner bag by additionally adhering a reinforcing tape or the like thereon.
There has been proposed a method of manufacturing a tubular resin absorbent material by overlapping both end portions in the width direction of a strip-shaped resin absorbent material, and sewing the overlapped end portions by straight sewing such as main sewing, through sewing or the like in order to reduce a time required for a sewing process as well as to narrow a width of the strip-shaped resin absorbent material required for the sewing to simplify a sealing operation for a joint.
With this method, however, a sewing margin remains at the joint on the outer surface of the resultant tubular resin absorbent material, and may cause an impediment in covering a plastic film over the outer surface of the tubular resin absorbent material. Thus, a sealing process or an air-tight sealing process is difficult to perform on the tubular resin absorbent material with a plastic film unless any processing is added to the sewing margin.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has been made in view of the problems mentioned above, and it is an object of the invention to provide a method of manufacturing a pipe liner bag which is capable of reducing a time required to join both ends of a resin absorbent material, and simplifying a sealing operation after the ends have been joined.
To achieve the above object, according to a first aspect, the present invention provides a method of manufacturing a pipe liner bag comprising a tubular resin absorbent material having an outer surface covered with a highly air-tight plastic film and a hardenable resin impregnated in the tubular resin absorbent material, the method comprising the steps of folding a strip-shaped resin absorbent material and aligning both ends thereof in the width direction; straight sewing overlapped portions to form a tubular resin absorbent material while leaving a sewing margin; turning the tubular resin absorbent material inside out such that a previous inner surface thereof appears outside; and welding or adhering a plastic film entirely or partially on the outer surface of the tubular resin absorbent material to air-tight seal the outer surface.
According to another aspect, the present invention provides a method of manufacturing a pipe liner bag comprising a tubular resin absorbent material having an outer surface covered with a highly air-tight plastic film and a hardenable resin impregnated in the tubular resin absorbent material, the method comprising the steps of folding a strip-shaped resin absorbent material having a surface thereof covered with a plastic film such that the plastic film is placed inside, and aligning both ends of the strip-shaped resin absorbent material in the width direction; straight sewing overlapped portions to form a tubular resin absorbent material while leaving a sewing margin; turning the tubular resin absorbent material inside out such that a previous inner surface thereof appears outside; and welding or adhering a sealing ribbon tape on the outer surface of the tubular resin absorbent material covering a joint to air-tight seal the outer surface.
Preferably, the sewing margin of the tubular resin absorbent material has been previously joined.
According to a further aspect, the present invention provides a method of manufacturing a pipe liner bag comprising a tubular resin absorbent material having an outer surface covered with a highly air-tight plastic film and a hardenable resin impregnated in the tubular resin absorbent material, the method comprising the steps of folding a strip-shaped resin absorbent material and abutting both ends in a width direction of the strip-shaped resin absorbent material; welding or adhering a joint reinforcing tape on abutted ends to form a tubular resin absorbent material; turning the tubular resin absorbent material inside out such that a previous inner surface thereof appears outside; and welding or adhering a sealing ribbon tape on the outer surface of the tubular resin absorbent material covering a joint to air-tight seal the outer surface.
According to a further aspect, the present invention provides a method of manufacturing a pipe liner bag comprising a tubular resin absorbent material having an outer surface covered with a highly air-tight plastic film and a hardenable resin impregnated in the tubular resin absorbent material, the method comprising the steps of folding a strip-shaped resin absorbent material having a surface thereof covered with a plastic film, and abutting both ends in a width direction of the strip-shaped resin absorbent material; welding or adhering a joint reinforcing tape on abutted ends of the strip-shaped resin absorbent material to form a tubular resin absorbent material; turning the tubular resin absorbent material inside out such that a previous inner surface thereof appears outside; and welding or adhering a sealing ribbon tape on the outer surface of the tubular resin absorbent material covering a joint to airtight seal the outer surface.
In the methods set forth above, a joint clearance
Aoki Hiroyuki
Endoh Shigeru
Kamiyama Takao
Yokoshima Yasuhiro
Knable Geoffrey L.
Knobbe Martens Olson & Bear LLP
Rossi Jessica
Shonan Gosei-jushi Seisakusho K.K.
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