Valves and valve actuation – With means to increase head and seat contact pressure – Gate valve
Reexamination Certificate
2000-03-07
2001-09-04
Shaver, Kevin (Department: 3754)
Valves and valve actuation
With means to increase head and seat contact pressure
Gate valve
C251S326000
Reexamination Certificate
active
06283446
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gate valve system that is capable of cutting an existing pipe with water flowing therethrough or the like therein without cutting off the water.
2. Discussion of the Background
In the following description, the terms, “lateral”, “vertical” and “downward”, as well as “downwardly”, “laterally” and “vertically”, or other terms indicating the directions, used herein are meant to indicate those directions as viewed in a front view as shown in
FIG. 22
, and based upon the longitudinal axis of the gate valve system installed on the existing pipe.
A well known method of cutting an existing pipe with water flowing therethrough includes boring the wall of an existing pipe without cutting off the water therein during forming a through-hole, and placing a gate valve into the pipe through the through-hole formed in the wall of the pipe. It is desirable to form the through-hole as smaller as possible, specifically the through-hole of a diameter smaller than the diameter of the pipe.
To form the through-hole of such a smaller diameter, the gate valve needs to be of such a construction as to be placed into the inside of the pipe via the through-hole having a diameter small than the diameter of the pipe, as well as to be capable of hermetically sealing the inside of the pipe for cutting off the water flowing therethrough. To accomplish these requirements, the gate valve includes a support member
61
, and a seal member
63
supported on the support member
61
, which exhibits an elastically deformable property for sealing the existing pipe
62
.
The gate valve of the above type accomplishes the water cutting-off by forcing the support member
61
into the existing pipe having a circular cross section via the through hole of a diameter smaller than the diameter of the existing pipe
62
to allow the seal member
63
to hermetically contact the inner surface of the existing pipe
62
.
However, the curved surface of the pipe may hesitate the seal member
63
from sufficiently expanding towards lateral sides of the pipe, and therefore pose a problem that a part of the peripheral edge portion of the seal member
63
cannot reach the inner surface of the pipe
62
, and therefore a hermetic contact of the seal member
63
against the pipe
62
is hardly accomplished, which leads to a poor water tightness. To overcome this problem, some types of members for laterally expanding the seal member
63
were developed.
The means for laterally expanding the seal member
63
has such a construction that a plurality of seal expanding members are arranged inside of the support member
61
to mechanically expand the seal member
63
. This may need a complicated structure and a relatively large size of the gate valve, which are disadvantageous for the existing pipe of a smaller diameter, and which also increase the manufacturing costs.
The present invention has been conceived in consideration of the above problem. It is an object of the present invention to provide a gate valve system that is of a simple construction and a smaller size.
It is another object of the present invention to provide a gate valve system that is capable of sufficiently cutting off the water flowing through the existing pipe.
It is still another object of the present invention to provide a gate valve system that can be manufactured in a cheap manner.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a gate valve system for cutting off a fluid flowing through a pipe. The gate valve system includes a gate valve and at least one member. The gate valve includes a seal member exhibiting an elastically deformable property for sealingly contacting the inner surface of the pipe, and a support member for receiving said seal member and movable in the perpendicular direction to the flowing direction of the fluid between the outside and inside of the pipe for timely bringing said seal member into a sealing contact with the inner surface of the pipe. The at least one expansion member is deformable, but is not substantially subjected to the volume variation even under pressure. The at least one expansion member is embedded in the seal member in such a manner as to expand the seal member laterally outwardly to the inner surface of the pipe upon receiving pressure effected by the sealing contact between the seal member and the inner surface of the pipe.
In the gate valve system of the above arrangement, the at least one expansion member embedded in the seal member can forcibly expand the seal member laterally outwardly to the inner surface of the pipe against the elastic force of the seal member upon receiving the pressure effected by the contact between the seal member and the inner surface of the pipe. This arrangement can simplify the structure of the gate valve system and reduce the dimension of the same, while accomplishing sufficient water tightness even for the pipe of a smaller diameter. Furthermore, the gate valve system of the present invention can be manufactured at low costs.
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patent: 3662778 (1972-05-01), Leopold, Jr.
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patent: 3931953 (1976-01-01), Allen
patent: 3957245 (1976-05-01), Daghe
patent: 3963214 (1976-06-01), Hackman et al.
patent: 3993092 (1976-11-01), Still
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patent: 4541613 (1985-09-01), Barbe
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patent: 5439024 (1995-08-01), Zimmerly
patent: 406159527-A (1994-06-01), None
Fujisaki Hiroshi
Ito Yasuhiko
Nishigaki Koichi
Sato Toshiyuki
Yamashita Tamotsu
Bastianelli John
Fulbright & Jaworski L.L.P.
Shaver Kevin
Suiken Technology Co., Ltd.
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