Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
2001-01-11
2003-09-23
Lee, Kevin (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C137S015120, C137S318000, C138S094000
Reexamination Certificate
active
06622747
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for effecting cutting, valve insertion and anticorrosive works on an existing pipe without a need to interrupt the supply of a fluid therethrough.
2. Description of the Related Arts
Up until now, a fluid supply interruption free valve insertion method is widely known in which a water flow through a pipeline can be stopped by forming an opening in an existing pipe without interruption of the water supply and inserting a gate through the opening to thereby allow a stopping of the water flow through the pipeline (U.S. Pat. Nos. 3,948,282, 4,516,598, 5,611,365 and 5,732,728, U.S. patent application Ser. No. 09/195,601 (Japan Patent Laid-open Pub. Nos. Hei11-287385 and 2000-179779)).
In such a method, the water flow is stopped by a gate after the valve insertion in order to perform the objective work such as a modification of piping.
The method disclosed in U.S. Pat. No. 5,732,728 includes enabling a gate passage aperture for inserting the gate therethrough to be opened or closed by sealing means and inserting a cutting tool through the gate passage aperture to cut the existing pipe. After the completion of the cutting, the massive sealing means are opened or closed to withdraw the cutting tool and thereafter insert the gate.
In this conventional method, the cutting tool is not to be withdrawn unless the massive sealing means are opened and closed. It is also required to deeply dig the earth beneath the existing pipe due to the necessity to cut the existing pipe over the entire circumference.
FIG. 44
is a transverse sectional view of an apparatus for use in the method disclosed in Japan Patent Laid-open Pub. No. Hei11-287385.
As shown, a seal-up housing
500
consists of a lower housing part
501
and an upper housing part
502
. The lower housing part
501
is mounted with a drill
505
having a cutting tool
504
. The upper housing part
502
is blocked off by a block-off plate. In this conventional method, a cut groove is first formed over the entire circumference of the existing pipe
1
by means of the cutting tool
504
. Then, after the completion of the cutting, the block-off plate
503
is withdrawn and thereafter a gate not shown is mounted on the upper housing part
502
.
This conventional method needs a deep dig of the earth beneath the existing pipe
1
due to the attachment of the drill
505
to the lower housing part
501
.
FIG. 45
is a transverse sectional view showing the state where the valve insertion is complete by use of the method disclosed in Japan Patent Laid-open Pub. No. 2000-179779.
As shown, a seal-up housing
600
consists of a first housing part
601
and a second housing part
602
. The first housing part
601
is provided with an aperture
603
for inserting a cutting tool not shown therethrough and with an operation valve
604
. The first housing part
601
is further provided with a gate passage aperture
606
through which a gate
605
passes upon the opening or closing thereof.
In this conventional method, the seal-up housing
600
is turned through substantially half the circumference so as to allow the cutting tool to form a cut groove
607
in the existing pipe
1
by a half round. Then, after the withdrawal of the cutting tool, the operation valve
604
is closed.
This conventional method posed quite a few problems from the above description.
Due to the necessity to turn the massive gate
605
and the seal-up housing
600
, the increased nominal diameter (bore) of the existing pipe
1
results in a larger-scale unit for turning the seal-up housing
600
around the existing pipe
1
.
After the completion of the objective work such as the modification of piping, it may possibly be difficult to withdraw the gate
605
or it may take a lot of time and labor for the withdrawal. For this reason, this method is not suited for the case where the existing pipe
1
is buried at a shallow depth.
Due to its formation by drilling or cutting, the cut groove (opening) of the above conventional methods has not undergone sufficient corrosion-resistant measures.
In case of less than 25 mm diameter piping water supply work, a hollow copper bush is caulked and inserted into such an opening to thereby take corrosion-resistant measures.
Due to the need for the step of spreading and caulking the bush, however, such corrosion resistant measures could not be applied to the case of larger bore as in the water distribution work (more than 50 mm diameter). Furthermore, the method may become complicated since the opening is not hermetically closed.
SUMMARY OF THE INVENTION
In order to solve the above problems, the anti corrosive member of the present invention is one for use in a fluid supply interruption free work hermetically closing a circular or grooved opening formed in an existing pipe through about 180 degrees or through the angular range slightly smaller than 180 degrees in the circumferential direction of the existing pipe. The anticorrosive member has a shape corresponding to the opening but is incapable of impeding the flow of water through the interior of the existing pipe (i.e., the anti corrosive member does not act as a valve body). The anticorrosive member comprises a pressure contact portion made of elastomer coming into pressure contact with a cut surface of the opening over substantially the entire periphery; and a rigid portion integrally formed with the pressure contact portion and having a rigidity enough to resist the water pressure acting on the opening.
The circular opening may be formed by means of a known hole saw. The grooved opening may be formed by an end mill or a fraise.
In the present invention, the “rigid portion” is typically made of ductile cast iron, steel, stainless steel, etc.
Such an anticorrosive member is enclosed in the seal-up housing together with the following gate to make up an anticorrosive member inserting apparatus.
In this case, the gate enters the interior of the existing pipe by way of the opening to cut off the flow of water through the interior of the existing pipe. On the other hand, the seal-up housing comprises a plurality of housing parts segmented in the circumferential direction of the existing pipe and encloses the anticorrosive member and the gate.
The fluid supply interruption free method of the present invention uses the anticorrosive member inserting apparatus, etc., and comprises an enclosing step, an opening formation step, a water stop step, a removal step and a hermetically closing step which will be described hereinbelow.
The enclosing step includes hermetically enclosing a part of an existing pipe by the seal-up housing.
The opening formation step includes forming a circular or grooved opening in the existing pipe within the seal-up housing, the opening extending through about 180 degrees or through the angular range slightly smaller than 180 degrees.
The water stop step includes stopping the flow of water through the interior of the existing pipe by allowing a gate for stopping the flow of water through the interior of the existing pipe to enter the interior of the existing pipe through the opening.
The removal step includes removing the gate from the opening.
The hermetically closing step includes fitting the anticorrosive member into the opening, the anticorrosive member including a pressure contact portion made of elastomer coming into pressure contact with a cut surface of the opening over substantially the entire periphery, and a rigid portion integrally formed with the pressure contact portion and having a rigidity enough to resist the water pressure acting on the opening.
By use of such a fluid supply interruption free method, a piping structure of the present invention is obtained.
More specifically, the piping structure of the present invention comprises an existing pipe and an anticorrosive member. The existing pipe has an outer peripheral surface formed with a cut opening, the opening extending through about 180 degrees or through the angular range slightly less than 180 degr
Sato Toshiyuki
Yamashita Tamotsu
Jordan and Hamburg LLP
Lee Kevin
Suiken Co., Ltd.
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