Pipes and tubular conduits – Repairing – Patches
Reexamination Certificate
1999-12-14
2002-06-11
Canfield, Robert (Department: 3635)
Pipes and tubular conduits
Repairing
Patches
C138S097000, C052S020000, C052S514000, C052S515000, C156S094000, C156S287000, C405S303000, C405S154100, C425S011000, C264S031000, C264S269000
Reexamination Certificate
active
06401759
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to manhole lining techniques, and more particularly to a liner bag for use in lining of a manhole, which has a two-layer structure composed of an inner-layer liner bag and an outer-layer liner bag, and a method of lining a manhole using this two-layer liner bag.
2. Description of the Related Background Art
When a manhole having a reducer section toward an opening becomes defective or too old to perform properly, the manhole is repaired and rehabilitated by lining the inner wall thereof without digging the earth to expose the manhole and disassembling the sections of the manhole. This non-digging method of repairing a manhole has been known and practiced commonly in the field of civil engineering.
A liner bag for use in lining of a manhole is typically designed to have a relatively large thickness so as to endure water pressure and earth pressure for a long term.
It is however extremely difficult to shape a thick resin absorbent material into a complicated bag form conformal to the shape of an existing manhole including a reducer and so on. On top of that, it is almost impossible to air-tight coat a plastic film, serving as a fluid pressure barrier film, on the surface of such a resin absorbent material in the form of a bag.
To overcome the difficulties inherent to the lining of a manhole, there has been proposed a method of lining a manhole using a fluid pressure barrier liner which is separate from a liner bag. This manhole lining method will be described below with reference to
FIGS. 8
to
10
.
FIGS. 8
to
10
are cross-sectional views illustrating a conventional manhole lining method in order. Specifically, in this manhole lining method, a manhole lining bag
101
is inserted into an existing manhole
106
from the ground, and an opening at the upper end of the lining bag
101
is fitted on a lower portion of a fixing collar
107
installed on the ground, as can be seen in FIG.
8
. The liner bag
101
is formed of a tubular resin absorbent material which has a portion formed to match the shape of a reducer section
106
a
of the existing manhole
106
(tapered form), and an unhardened thermosetting resin impregnated in the resin absorbent material.
In addition, a fluid pressure barrier liner
130
formed of a highly air-tight plastic tube is folded out such that one end thereof is also fitted on the lower portion of the fixing collar
107
. When the insertion of the liner bag
101
into the manhole
106
is completed, water is poured into the inside of the folded-out fluid pressure barrier liner
130
from a water supply hose
115
. The poured water causes the fluid pressure barrier liner
130
, receiving the pressure (weight) of the water, to evert and go downward into the lining bag
101
.
Then, after the fluid pressure barrier liner
130
has been completely everted and inserted into the liner bag
101
, a hot water hose
118
attached to an extreme end of the fluid pressure barrier liner
130
is drawn into the fluid pressure barrier liner
130
, as illustrated in FIG.
9
. The cross-sectional view of
FIG. 9
includes, as tools associated with the lining of the manhole
106
, a pipeline
108
running below the manhole
106
; a water passing hose
109
for passing water within the pipe line
108
during the lining of the manhole; a filler
110
; and water stopping plugs
127
,
128
.
Next, as illustrated in
FIG. 9
, a cap
116
is placed on the upper opening of the fixing collar
107
and secured to the same to form a sealed space S within the fluid pressure barrier liner
130
.
The hot water hose
118
and a drain hose
119
have been drawn into the sealed space S. A portion of the drain hose
119
extending out of the sealed space S has an end open to the top of a hot water tank
120
installed on the ground.
A water supply pipe
121
extending from a lower portion of the hot water tank
120
is connected to an inlet of a boiler
122
, and a hot water pump
123
is interposed on the middle of the water supply pipe
121
. One end of the hot water hose
118
is connected to the outlet side of the boiler
122
. In addition, an air hose
125
extending out from a compressor
124
is connected to the cap
116
.
When the compressor
124
is driven to supply compressed air into the sealed space S through the air hose
125
, the fluid pressure barrier liner
130
and the liner bag
101
are pressed onto the inner wall of the manhole
106
by the pressure of the compressed air.
Next, with the foregoing condition being maintained, the boiler
122
and the hot water pump
123
are driven to supply the hot water within the hot water tank
120
to the boiler
122
. After heated to a predetermined temperature by the boiler
122
, the hot water is supplied into the sealed space S through the hot water hose
118
. Specifically, the hot water running through the hot water hose
118
is sprayed out into the sealed space S just like shower from a plurality of spray holes formed through a portion of the hot water hose
118
that faces the sealed space S.
The hot water, which has served to heat the liner bag
101
and cooled down, drops and accumulates in the bottom of the sealed space S. This hot water accumulating in the bottom is urged by an inner pressure of the sealed space S to go back to the hot water tank
120
through the drain hose
119
. Then, it is again supplied to the boiler
122
by the hot water pump
123
, and heated by the boiler
122
. Subsequently, the foregoing operations are repeated.
When the hot water is cyclically sprayed out from the hot water hose
118
through the circuit formed of the hot water hose
118
, the drain hose
119
, the hot water tank
120
, the water supply pipe
121
, the hot water pump
123
and the boiler
122
, the lining bag
101
is heated to cause the thermosetting hardenable resin impregnated therein to be uniformly hardened. After the thermosetting resin impregnated in the lining bag
101
has been hardened, the fluid pressure barrier liner
130
is stripped off to remove the same from the lining bag
101
, as illustrated in FIG.
10
. As a result, the inner wall of the manhole
106
has been lined or repaired by the hardened liner bag
101
, followed by the completion of a sequence of the lining works after unnecessary portions of the hardened liner bag
101
are cut.
The conventional manhole lining method described above, however, implies problems related to the durability of the hardened liner bag and the working cost. Specifically, since the fluid pressure barrier liner
130
is stripped off and disposed as waste after the completion of the lining, the durability of the liner bag cannot be increased by covering the surface of the hardened liner bag
101
, after lined on the inner wall of the manhole, with a barrier film. In addition, an effort of stripping off the fluid pressure barrier liner
130
is additionally required, with an additional cost for disposing the stripped fluid pressure barrier liner
130
as a waste.
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 present invention to provide a liner bag for a manhole which can have an improved durability after hardening with a fluid pressure barrier film being left on the inner wall of a manhole to be lined, and a method of lining a manhole using the liner bag which is capable of realizing a reduction in the number of steps involved in a manhole lining process to reduce a working time and a working cost.
To achieve the above object, in a first aspect of the present invention, there is provided a liner bag for a manhole which comprises an outer-layer liner bag including a first bag-shaped resin absorbent material, and an unhardened liquid hardenable resin impregnated in the first bag-shaped resin absorbent material, and an inner-layer liner bag including a second bag-shaped resin absorbent material, a highly air-tight plastic film coated over an inner surface of the second bag-shaped resin abs
Aoki Hiroyuki
Endoh Shigeru
Kamiyama Takao
Yokoshima Yasuhiro
Canfield Robert
Knobbe Martens Olson & Bear LLP
Shonan Gosei-Jushi Seisakusho K.K.
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