Valves and valve actuation – Tube compressors – Fluid pressure actuated
Reexamination Certificate
2002-08-02
2004-06-29
Look, Edward K. (Department: 3754)
Valves and valve actuation
Tube compressors
Fluid pressure actuated
C251S062000
Reexamination Certificate
active
06755388
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a pinch valve used in a fluid transport pipeline in various industrial fields, such as chemical factories, semiconductor production, food processing, biotechnology or the like, and more particularly, to a pinch valve which is compact and mitigates the damage a tube body suffers during opening and the closing of the valve.
BACKGROUND ART
Hitherto, various pinch valves have been proposed, and an example is disclosed in Japanese Examined Utility Model Publication No. 45-3264. According to this publication, as shown in
FIGS. 27 and 28
, in two upper and lower pistons
41
,
42
fitted in a cylinder
40
on a leg member
39
constituted by a leg stand
37
and leg rods
38
, the upper piston
41
is fixed to the upper end of a shaft rod
43
and the lower piston
42
is fixed to the upper end of a pipe shaft
44
loosely fitted on the shaft rod
43
. On the lower portion of the pipe shaft
44
is provided a wing piece
45
which is fixed to a lower pressing piece
47
via connecting bars
46
. On the other hand, an upper pressing piece
48
is fixed to the lower end of the shaft rod
43
. Also, the center portion of a valve tube body
51
supported by two lateral rods
50
spanning between flanges
49
fitted on both ends of the flow passage and the leg members
39
is pressed by the upper and lower pressing pieces
48
,
47
, then the upper and lower pressing pieces
48
,
47
connected to the pistons
41
,
42
are symmetrically moved up and down by suitably forcing compressed air into holes
52
,
53
,
54
in the cylinder
40
, so that the valve tube body
51
is opened and closed.
Now, at the present, in an apparatus for manufacturing semiconductors in which various pipeline and control devices are arranged and complicated pipeline design is performed, allowing the apparatus per se to be compact has been required. As a result, a pinch valve used in the pipeline of the apparatus must be compact in order to save space, thus making the pinch valve used in the apparatus compact an important matter. Also, a pinch valve able to regulate a very small flow rate is required.
However, in the pinch valve described as above, since the actuator and the valve body are constituted as separate components, and the leg member
39
, the leg stand
37
and the wing piece
45
are provided between the cylinder
40
and the valve tube body
51
which is a flow passage, the overall height of the valve is very large and thus the valve cannot be made compact. Consequently, the above pinch valve cannot be used as a pinch valve in the pipeline of a semiconductor manufacturing apparatus. Also, since, in the pinch valve of such construction, it is difficult to optionally adjust the degree of opening the valve tube body, adjustment of a very small flow rate cannot be performed.
DISCLOSURE OF INVENTION
The present invention has been conceived in view of the problems of the prior art as stated above, and the purpose of this invention is to provide a pinch valve the overall height of which is low in comparison with the conventional pinch valve, which is compact, which remarkably improves the durability of the tube body pipelined in the apparatus during opening and closing of the valve, and which is able to adjust a very small flow rate.
In order to achieve the above purpose, as a result of extensive research, the inventors have found that a pinch valve could be made very compact by integrally constituting a drive and a valve body. That is, explaining the constitution of this invention with reference to
FIGS. 1
to
8
, a pinch valve according to a first embodiment of the invention is characterized in that it comprises a tube body
1
made of an elastic body, a cylinder body
4
having a cylinder portion
2
thereinside and joined to a disk-like cylinder cover
3
at the upper portion thereof, a piston
11
sliding up and down on the inner periphery of the cylinder portion
2
in a sealing manner and having a connecting portion
13
suspending from the center of the lower surface of the piston to penetrate a through hole
5
provided in the center of the lower surface of the cylinder body
4
in a sealing manner, a pressing piece
15
fixed to the lower end of the connecting portion
13
of the piston
11
and contained in an oval slit
6
provided on the bottom surface of the cylinder body
4
perpendicularly to the axis of a flow passage, a body
16
joined and fixed to the lower end surface of the cylinder body
4
, having a groove
17
for receiving the tube body
1
on the axis of the flow passage and having grooves
18
for receiving connecting body carriers
20
which are arranged on both ends of the groove
17
and deeper than the groove
17
, a pair of connecting body carriers
20
each having a fitting portion
21
fitted in the groove
18
of the body
16
at one end of the carrier
20
and a connecting body carrier port
23
on the inner surface of the other end of the carrier
20
and having a through-hole
26
for receiving the tube body
1
, and a pair of air ports
9
,
10
provided on the peripheral side surface of the cylinder body
4
and communicating with a first space portion
7
surrounded by the bottom surface and inner periphery of the cylinder portion
2
and the lower end surface of the piston
11
, and a second space portion
8
surrounded by the lower end surface of the cylinder cover
3
, the inner periphery of the cylinder portion
2
and the upper surface of the piston
11
.
The pinch valve according to the first invention is also characterized in that the connecting body carrier
20
is provided at a fitting portion
21
thereof with a ledge portion
22
for preventing the connecting body carrier
20
from slipping out, and the body
16
is provided at the groove
18
thereof with a recessed groove
19
for receiving the ledge portion
22
for preventing the carrier
20
from slipping out.
In addition, the pinch valve according to the first invention is characterized in that a spring
35
is installed in the second space portion
8
in the condition where the spring
35
contacts the cylinder cover
3
and the piston
11
, and is also characterized in that a spring
35
is installed in the first space portion
7
in the condition where the spring
35
contacts the bottom surface of the cylinder portion
2
and the piston
11
.
Further, the pinch valve according to the first invention is characterized in that a connecting body
29
having an inserting portion
31
formed with an outer diameter larger than the inner diameter of the tube body
1
at one end of the connecting body
29
and inserted in and connected to the tube body
1
, a pipeline connecting portion
32
at the other end of the connecting body
29
and a flange portion
33
at the center of the connecting body
29
is fitted in and fixed to the connecting body carrier
20
by engaging a cap nut
34
with the flange portion
33
and screwing the cap nut
34
to a male screw portion
24
provided on the outer periphery of the connecting body carrier
20
.
Also, the pinch valve is characterized in that the material of the tube body
1
is EPDM, fluororubber, silicone rubber or a composition of these materials, and is further characterized in that the tube body is made of a composition of polytetrafluoroethylene and silicone rubber.
Although the tube body
1
of the pinch valve according to the invention may be made of EPDM, fluororubber, silicone rubber or an elastic body such as a composition of fluororubber and silicone rubber and is not limited to these materials, a composition of fluororubber and silicone rubber is especially preferable.
Also, although the cylinder body
4
and the body
16
may be made of a material having rigidity, such as metal or plastic, and thus the materials of those components are not especially limited, a fluororesin plastic, such as PVC, PVDF or the like is especially preferable.
Furthermore, explaining the constitution of a pinch valve according to the second invention with reference to
FIGS. 15
to
26
, the pinch valve is characteri
Furukawa Shigenobu
Hamada Takeshi
Asahi Organic Chemicals Industry Co., LTD
Burns Doane , Swecker, Mathis LLP
Fristoe, Jr. John K
Look Edward K.
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