Plug for blocking a branched pipe opening

An apparatus for blocking the openings of a branched pipe (2) in a branched portion of a pipeline (1) prior to lining the inner surface of the pipeline (1) with a tubular lining material (100) for maintenance/repair or reinforcement purposes includes a spring-biased plug-housing assembly which carries a plurality of plugs for blocking the branch pipe openings. The plugs are installed one at a time into the branch pipe openings and are retained in the openings by a friction fit. The plug-housing assembly dispenses one plug at a time without the possibility of inadvertent dispensing of the remaining unused plugs. The plugs have cut-away portions in the outer periphery thereof, which cut-away portions cooperate for storage and installation purposes with struts on the plug-housing assembly.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to techniques for applying a lining material to the 
inner surface of a pipeline such as a gas conduit, a city water pipeline, 
a sewer conduit, a conduit in which power cables or communication cables 
are laid or a petroleum pipeline and particularly an underground pipeline, 
for the purposes of maintenance, repairs and/or reinforcement. 
2. Description of Related Art 
Methods of applying a lining material to the inner surfaces of such 
pipelines or conduits have been used for the purposes of maintenance, 
repairs and/or reinforcement of various kinds of conduits such as 
inserting the lining material into a pipeline while the lining material is 
being turned inside out by the action of fluid pressure, pressing the 
evaginated surface of the lining material against the inner surface of the 
pipeline through the action of the above-mentioned fluid pressure, and 
adhesively bonding the inner surface of the lining material onto the inner 
surface of the pipeline. 
However, in case such a lining method is applied to a pipeline having one 
or more branched portions to line the inner surface thereof, at the 
initial stage the lining material is adhesively bonded onto the whole 
inner surface of the pipeline, and as a result, the openings of the 
branched pipes formed in the main pipeline also become covered by the 
lining material, i.e., blocked thereby. At the next or second stage, the 
lining material layer covering the openings of the branched pipelines is 
removed by boring the same by means of a borer to thereby enable the 
branched pipes to communicate with the main pipeline. Upon effecting such 
a lining operation, if at the above-mentioned initial stage the lining 
material is adhesively a borer at the above-mentioned second stage, this 
thick solidified adhesive layer has to be removed, and such removal 
operations are difficult. To avoid such difficulties, upon effecting 
adhesive bonding of a lining material onto the inner surface of a main 
pipeline at the initial stage of the lining operation, the openings of 
branched pipes in branched portions have been covered with sealing 
materials prior to conducting the lining material bonding operation. Upon 
boring the portions of the lining material layer covering the openings 
during the above-mentioned second stage, the above-mentioned sealing 
material is then removed together with each of the bored-out portions of 
the lining material. 
An apparatus for blocking openings of branched pipes in branched portions 
with sealing materials in the above-mentioned operation is described in 
Japanese Laid-Open Patent Application No. SHO 62-16127. This apparatus 
comprises a base, on which sealing materials or plugs for blocking 
openings of branched pipes in branched portions of a pipeline are placed, 
the base being mounted on an operating machine that is movable through the 
pipeline, in such a manner that it may be rotated about the longitudinal 
axis of the pipeline and also moved radially within the pipeline. 
This apparatus is disadvantageous in that, since it can carry only one 
piece of sealing material or plug at a time, each time one of the openings 
of the branched pipes has to be blocked with a plug, the whole apparatus 
itself needs to be removed from the pipe in order to place thereon a 
separate plug for use in blocking the next opening. 
Stating this disadvantage in more detail, in general, most of the various 
kinds of conduits and pipelines such as the above-mentioned gas conduits, 
city water pipelines and sewers, etc. have a plurality of branched 
pipelines extending therefrom in the regions close to the terminal ends 
thereof. For example, low pressure pipelines of gas conduits are buried in 
the ground under city roads to supply city gas through branched pipelines 
to neighboring houses and buildings. Many branched pipelines extend from a 
main pipeline at short intervals. Further, this situation applies also to 
city water pipelines and sewer conduits. 
If the apparatus described in the above-mentioned Japanese Laid-Open Patent 
Application No. SHO 62-16127 is used for a pipeline having a plurality of 
branched pipes extending therefrom at short intervals between them, each 
time one of the openings of the branched pipes has to be blocked with a 
plug, an extremely inefficient operation of removing the apparatus from 
the pipeline and placing thereon a new plug for blocking the next opening 
has to be carried out. 
The main object of the present invention is to provide a novel apparatus 
for use in a pipeline having branched pipes which is free from the 
above-mentioned disadvantages in the prior art apparatus. 
SUMMARY OF THE INVENTION 
A first object of the present invention is to provide an improved apparatus 
for blocking each of the openings of branched pipelines formed in branched 
portions of a main pipeline, by using a plug. Further, the present 
invention has for its second object to provide an efficient plug for use 
in blocking the openings of such branched pipes. 
According to the present invention, there is provided a plug for blocking 
the a branched pipe opening from an interior of the pipe 
This plug is characterized in that it comprises a disc-shaped body having 
an outer peripheral flange of a diameter slightly larger than an inside 
diameter of said opening, a projecting portion formed on a side of said 
disc-shaped body facing an interior of the pipe, said projection portion 
being shaped so as to engage with an inner peripheral edge of said opening 
via frictional force and, a convex portion formed within the outer 
peripheral flange of said disc-shaped body and of a smaller diameter than 
a diameter of said opening, on a side opposite to the side on which said 
projecting portion is formed and the convex portion extending toward the 
interior of said pipe, and all the disc-shaped body and the projecting 
portion are formed integrally of a plastic material. 
According to the present invention, there is provided a plug having a 
construction which will be described below. 
This plug is characterized by incorporating the following requirements (1), 
(2) and/or (3). 
(1) The above-mentioned disc-shaped body shall have a spherical, convex 
portion formed integrally on the surface thereof on the opposite side of 
the surface provided with a projecting portion. 
(2) The above-mentioned disc-shaped body shall have a sealing member which 
is adhesively bonded onto the surface thereof provided with the projecting 
portion and which extends circumferentially of and around the projecting 
portion. 
(3) The above-mentioned disc-shaped body shall have a curved shape which is 
the same as that of the inner surface of the main pipeline in each of the 
branched portions to be blocked with the plugs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows the relationship between a blocking apparatus 10 of the 
present invention and the whole operating machine 3. 
Operating machine 3 is adapted to be inserted into a pipeline 1, having a 
branched pipe 2 extending therefrom, and slidably moved therethrough by a 
slide 5 mounted on the operating machine body 4 when a rod 6 or wire or 
the like connected to the rear portion of the body 4 is pulled. 
The operating machine body 4 has a turning unit 7 mounted on the front 
portion thereof in such a manner that it may be rotated about the 
longitudinal axis of the pipeline 1 relative to the body 4. The rotation 
of the turning unit 7 is accomplished by well-known mechanisms such as are 
used on the remotely controllable travelling robot disclosed in U.S. Pat. 
No. 4,648,454. See in particular, column 3, line 63, through column 4, 
line 9, and FIGS. 4a and 4b of this reference. The turning unit 7 has a 
television camera 8 mounted thereon. 
Further, the front portion of the turning body 7 has a movable member 9 
mounted thereon in a manner such that the movable member 9 it may be 
slidably moved vertically relative to the turning Unit 7; that is; 
radially of the pipeline 1. This radial movement of movable member 9 is 
also accomplished by well-known mechanisms such as are used in U.S. Pat. 
No. 4,648,454. See in particular, column 4, lines 53-59, and FIGS. 1, 5 
and 6 of this reference. The arrangement is made such that all of the 
movement of the operating machine 3 through the pipeline, turning of the 
turning unit 7 relative to the body 4, and the sliding movement of the 
movable member 9 relative to the turning unit 7 can be remotely controlled 
outside of the pipeline while monitoring images picked up by the 
television camera 8. The blocking apparatus 10 is mounted on the movable 
member 9 for inserting plugs into branched pipes 2. 
As shown in FIGS. 2A and 2B, a base 11 is detachably mounted through a 
plate 9' on the movable member 9 and fixedly secured thereto in such a 
manner that it may be moved together with the movable member 9 as an 
integral unit thereof. 
A sliding member 12 comprises plate 13 and a sliding rod 14. The sliding 
rod 14 is supported in the above-mentioned base 11 so as to move slidably 
in the vertical direction relative to the base 11. Further, the sliding 
member 12 is normally biased by a spring means 15 upwards relative to the 
base 11. 
A plate 16 is placed on the upper surface of the plate 13 and fixedly 
supported by struts 17 extending through the plate 13, relative to the 
base 11. Thus, the sliding member 12 is biased upwards by the spring means 
15 so that the upper surface of the plate 13 is pressed against the plate 
16. 
Further, the sliding member 12 has a plug housing member 18 formed on the 
upper part thereof. The plug housing member 18 comprises the plate 16 and 
a plurality of struts 19 which stand upright around the plate 16. The 
arrangement is made such that a stack of of plugs 20 can be accommodated 
in the space defined by the struts 19 and held thereby. And, the plate 16 
constitutes the bottom of the plug housing member 18. 
As shown in FIG. 2B, each of the above-mentioned struts 19 has a slit 21 
formed in the upper half portion thereof in which a wire spring 22 is 
fitted. A portion of each of the wire springs 22 projects inwardly to 
resiliently hold the plugs 20 accommodated along the struts 19. 
The plug 20 has such a shape as shown in FIG. 3, and is formed integrally 
of a plastic material. This plug comprises a disc-shaped body 23 whose 
diameter is slightly larger than-the inside diameter of the branched pipe 
2 to be blocked by the apparatus of the present invention. This 
disc-shaped body 23 has a plurality of cut-away portions 24 formed along 
the peripheral edge thereof at regular intervals so that each of the 
struts 19 of the plug housing member 18 of the blocking apparatus can fit 
loosely into in each of the cut-away portions 24. Further, the disc-shaped 
body 23 has a projecting portion 25 formed on the upper surface thereof 
and which has such a shape as to be fitted tightly in the inner surface of 
the branched pipe 2. In the embodiment shown in FIG. 3, the projecting 
portion 25 is formed by three pieces of strip-shaped ribs 26 assembled 
with one another. The leading end of each of the ribs 26 projects 
outwardly so as to define the apex of a triangle thus forming tapered 
pressure contact portions 26a, 26b and 26c. The arrangement is made such 
that the extreme ends 26a, 26b and 26c are engageable with the inner 
surface of the branched pipe 2 and held tightly in the end of the opening 
of the branched pipe 2 formed in the main pipeline. 
While in this embodiment the projecting portion 25 is formed by three 
pieces of ribs 26 assembled in a triangular shape, it may be formed in any 
desired shape provided that it has such a configuration as to be 
engageable with the inner surface of the branched pipe 2 at the branched 
portion through the action of a frictional force. 
FIGS. 5A, 5B, 5C and 6 show alternate embodiments of the improved plug of 
the present invention. 
Plugs 31 and 31' are each formed integrally of a plastic material and 
comprise disc-shaped bodies 32 and 32', respectively, which have a 
diameter slightly larger than the inside diameter of the branched pipe 2 
and also have cut-away portions 33 formed along the periphery of their 
bodies. Further, as the cut-away portions 33 are formed to accommodate the 
above-mentioned blocking apparatus, it is not always indispensable to form 
the cut-away portions 33 in terms of the function of the plug for use in 
blocking a branched pipe at a branched portion. 
Further, each of the above-mentioned disc-shaped bodies 32 and 32' has a 
projecting portion 34 formed on the upper surface thereof and having such 
a shape as to be fitted tightly into the inner surface of a branched pipe. 
Thus, in FIGS. 5A, 5B and 5C, the projecting portion 34 has a 
substantially hexagonal shape in plan view. The projecting portion 34 has 
pressure contact portions 35 formed at positions corresponding to three 
apexes of the hexagon so that they can be engaged tightly with the inner 
surface of a branched pipe through the action of a frictional force 
exerted between them. 
Further, each of the disc-shaped bodies 32 and 32' has a spherical, convex 
portion 36 formed in the central area of the lower surface thereof. 
Moreover, each of the above-mentioned disc-shaped bodies 32 and 32' has a 
sealing member 37 of an elastomer such as rubber adhesively bonded onto 
the upper surface thereof and around the outer periphery of the projecting 
portion 34. The upper surface of the sealing member 37 is applied with an 
adhesive or binder. 
FIG. 6 is a sectional view of another embodiment of the plug having an 
improved shape. This plug has a disc-shaped body 32' having a curved shape 
which is the same as that of the inner surface of a main pipeline in a 
branched portion to be blocked. The above-mentioned projecting portion 34 
is formed on the curved surface on the opposite side of the convex 
portion. 
As shown in FIG. 2, when the blocking apparatus 10 of the present invention 
is in its inoperative condition, the sliding member 12 occupies its upper 
position relative to the base 11, and the plate 13 is abutted against the 
lower surface of the plate 16 by the resilient force of the spring means 
15. Thus, the struts 19 project upwardly above the plate 16 to a maximum 
extent. In FIGS. 2A and 2B, a plurality of plugs 20 are accommodated in 
the plug housing member 18. 
Since the plugs 20 are held by the wire springs 22, they are fixedly 
secured in the plug housing member 20 so that even when the blocking 
apparatus 10 is inclined or directed laterally or downwardly from its 
position shown in FIGS. 1, 2A and 2B, according to the connecting position 
of the branched pipe 2, there is no risk of the plugs 20 dropping out from 
the plug housing member 18. 
The operation of this blocking apparatus is carried out as follows. 
The operating machine 3 with a plurality of plugs 20, 31 or 31' 
accommodated in the plug housing member 18 of the blocking apparatus 10 is 
inserted into the pipeline 1 and moved therethrough by operating the rod 6 
or the like, while the operator is viewing the inside of the pipeline 1 by 
means of the television camera 8 to search for the opening of the branched 
pipe 2. 
The position of the operating machine 3 is adjusted by the operator while 
viewing the image on the screen of the television camera 8, and as 
occasion demands the turning unit 7 is turned so as to locate the blocking 
apparatus 10 at the position of the opening of the branched pipe 2. 
When the apparatus 10 is located below the opening of the branched pipe 2, 
the movable member 9 of the operating machine 3 is moved upwards in the 
drawing so that the base 11 fixedly secured to the movable member 9 is 
moved upwards and is accompanied by upward movement of the sliding member 
12. 
The leading ends of the struts 19 first contact the leading end face of the 
branched pipe 2. When the movable member 9 is moved further upwardly from 
that condition, the sliding member 12 cannot be moved upwards because the 
leading ends of the struts 19 are held by the leading end face of the 
branched pipe 2 around the opening. Thus, the base 11 is moved upwards 
relative to the sliding member 12 while compressing the spring means 15 so 
that the plate 16 fixedly secured to the base 11 is moved upwardly away 
from the plate 13. As a result, the group of plugs 20 resting on the plate 
16 is pushed up along the struts 19. 
The plugs 20, 31 or 31' are moved upwards while spreading the wire springs 
22 mounted on the struts 19, respectively. Thereupon, the projecting 
portion 25 or 34 of the uppermost plug is fitted into the inner surface of 
the opening of the branched pipe 2 so that the projecting portion is 
engaged with the inner surface of the branched pipe 2 and held thereby. 
Thus, the plug is held at the branched portion so as to cover the opening 
of the branched pipe 2 by the disc-shaped body. This condition is 
illustrated in FIG. 4. 
When the movable member 9 is moved down subsequently, only the base 11 is 
moved down together with the plate 16 while the leading ends of the struts 
19 remain pressed against the leading end face of the branched pipe 2. 
When the plate 16 abuts against the upper surface of the plate 13, the 
sliding member 12 is also moved down so that the whole blocking apparatus 
is returned eventually to its initial condition as shown in FIG. 2. 
Then, out of the group of plugs accommodated previously in the plug housing 
member 18, the uppermost plug remains to be held in the opening of the 
branched pipe 2, and the rest of the plugs accommodated in the plug 
housing member 18 will be moved down together with the sliding member 12. 
The opening of one of the branched pipes is blocked with the plug by the 
above-mentioned operation. Subsequently, the operating machine 3 is moved 
in turn to each of the openings of the branched pipes where the same 
operation is repeated, so that one plug is fitted into turn in each of the 
openings of branched pipes 2 thus blocking the openings. Therefore, by 
inserting the operating machine 3 once into the pipeline 1, the openings 
of branched pipes corresponding in number to the plugs accommodated in the 
plug housing member 18 can be blocked. 
After all of the openings of branched pipes in the pipeline 1 have been 
blocked, the inner surface of the pipeline 1 is lined with a lining 
material according to a known method. The condition of the pipeline which 
has been lined is illustrated in FIGS. 7 and 8. 
After the completion of the lining operation, the base 11 is removed from 
the movable member 9 mounted on the turning unit 7, and then a proper 
boring device is mounted onto the operating machine 3 in place of the 
blocking apparatus 10. Then, the operating machine 3 is inserted again 
into the lined pipeline. Subsequently, by driving the boring device, only 
the portions of the lining material adhesively bonded on the inner surface 
of the pipeline covering each of the openings of branched pipes are 
removed together with the plug 20, 31 or 31'. Thus, communication is 
restored between the branched pipes 2 and the pipeline 1. As a boring 
device for use in boring the lining material covering the branched 
portions of the pipeline various kinds of constructions using a drill, a 
striker or a heating iron are proposed. If, for example, it is desired to 
burn off the lining material covering the openings of the branched pipes 
by using a heating-iron type borer, then an EVA resin whose melting point 
is low should preferably be selected, because this resin can be readily 
bored, and can seal the periphery of holes formed in the lining material 
layer. 
Further, if a plug having a convex portion 36 formed in the central, lower 
surface thereof like the plugs 31 and 31' shown in FIGS. 5A-5C and 6 is 
used, and the inner surface of the lined pipeline is observed by the 
operator by means of the television camera 8, the projecting condition of 
the lining material layer 100 at the position of the opening of the 
branched pipe 2 can be easily confirmed through its image on the screen of 
the television camera. Therefore, it is convenient to use such a type of 
plug to find the location of the opening. 
Further, by using a plug with an abraded lower surface, an enhanced 
adhesion can be achieved between the lower surface and the lining material 
layer 100 so that leakage of fluid after the boring operation can be 
prevented. 
In the condition shown in FIG. 7, the leading end of the branched pipe 2 
projects inwardly from the inner surface of the pipeline 1, and the end 
face thereof is generally planar. In such a case, a plug having a 
flat-plate type disc-shaped body 32 as shown in FIGS. 5A, 5B and 5C is 
used, and the branched portion can be blocked with this plug by engaging 
it with the inner surface of the branched pipe 2. 
Whilst, in case the inner end of the branched pipe 2 is cut flush with the 
inner surface of the pipeline 1 as shown in FIG. 8, or in case the 
branched pipe 2 is welded to the periphery of a bored hole in the pipeline 
1, the opening of the branched pipe cannot be blocked satisfactorily with 
the plug as shown in FIGS. 5A-5C. In such a case, a plug having a curved 
disc-shaped body as shown in FIG. 6 is used, and this plug is fitted in 
the branched portion along the inner surface of the pipeline 1. 
According to the blocking apparatus of the present invention, since the 
inner surface of the pipeline 1 is lined with a lining material and the 
openings of branched pipes in branched portions of the pipeline 1 have 
previously been blocked satisfactorily with plugs, there is no risk of the 
adhesive used for bonding the lining material flowing into the branched 
pipe 2 and resulting in formation of a thick solidified adhesive layer 
which impedes boring operation in the branched pipe 2. Therefore, in the 
subsequent process of boring the lining material covering the openings of 
branched pipes, it is sufficient to remove only the thin lining material 
and the plugs 20, 31 or 31' by boring, and so the lining material covering 
the openings can be bored easily in a short time. 
Further, since the plug housing member 18 can accommodate a plurality of 
plugs, when the operating machine 3 is once inserted into the pipeline 1, 
a plurality of openings of branched pipes can be blocked continuously with 
the plugs, and so operational efficiency can be improved significantly. 
The plug according to the present invention can be fitted into the opening 
of a branched pipe very easily by a simple operation to block the branched 
portion of a pipeline, and after fitting there is almost no possibility of 
the plug dropping out of the plug housing member. 
Further, since the plug according to the present invention has a sealing 
member 37 bonded onto the upper surface thereof, even if the inner surface 
of the branched portion is somewhat irregular, the plug is pressed tightly 
against the inner surface along the irregularities through deformation of 
the sealing member 37, so that the branched portion can be sealed 
satisfactorily. 
Further, as mentioned hereinabove, when a plug having a sealing member 37 
applied with an adhesive or binder on the upper surface thereof is used, 
drop-out of the plug while blocking the opening of a branched pipe is 
prevented, and the branched portion can be sealed satisfactorily, thus 
preventing the ingress of adhesive into the branched pipe. 
As a result, there is no possibility of formation of a thick solidified 
adhesive layer in the branched pipe, which would impede the subsequent 
boring operation. 
Further, since the projecting portion 35 of the plug is of such a shape as 
to be fitted properly into the branched pipe, the branched portion can 
always be blocked securely with the plug. 
Furthermore, after completion of the lining operation the position of the 
branched portion can be found easily and exactly by viewing the image of 
the convex portion 36 formed on the lower surface of the disc-shaped body 
on the screen of the television camera, which offers convenience to the 
operation of boring the lining material covering the openings of branched 
portions.