Fluid handling – Diverse fluid containing pressure systems – Fluid separating traps or vents
Reexamination Certificate
2002-10-28
2004-08-17
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Fluid separating traps or vents
C251S357000
Reexamination Certificate
active
06776182
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. 2001-333570 filed on Oct. 30, 2002 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a stop valve for closing a fluid passage, more particularly, to a sealing structure of a stop valve with improved sealing performance in closing an opening portion by means of a float.
2. Description of the Related Art
Various kinds of stop valves have been used in various fields for closing fluid passages. In an automobile fuel tank for example, the opening portion which opens inside and outside of the fuel tank has a member provided with a valve body for detecting fuel reaching the opening portion. Consequently, if a vehicle tilts or falls down and thereby the fuel in the fuel tank reaches the opening portion, the member is activated so that the opening portion is closed by the stop valve.
Various kinds of such stop valves have been used. An example of known technology of such a valve is disclosed in Japanese Utility Model Application Laid-Open No.SHO50-134119. The valve is provided with, as shown in
FIG. 2A
, a valve seat portion
33
having an opening
32
disposed in a fluid passage
31
and a diaphragm
34
disposed facing the opening
32
. A valve supporting rod
35
is attached to the diaphragm
34
and a ring-shaped planar valve body
36
is attached to the valve supporting rod
35
. Consequently, the diaphragm is pressed by a fluid flowing into the fluid passage
31
a
, that is a primary pressure, and moves the valve body
36
and the valve supporting rod
35
. Then, the valve seat portion
33
is pressed by a surface
37
of the valve body
36
so as to close the opening
32
thereby preventing the fuel from flowing out.
The valve body
36
is made of elastic material. While the valve is not activated, there is provided a gap d, as shown in
FIG. 2B
, between a back face
38
of the valve body
36
and a top end face
40
of a step portion
39
of the valve supporting rod
35
. When the valve is activated as described above and as shown in
FIG. 2C
, the valve seat portion
33
is pressed by the surface
37
of the bendable valve body
36
so that the opening
32
is securely closed.
A stop valve
41
shown in
FIG. 3A
is another example of known stop valves. The stop valve
41
has a valve body fixed on a float, in which a passage closing member
42
is provided in a fluid passage leading from the fluid tank to the outside thereof, and a valve seat body
45
having an opening
44
fixed on a frame
43
of the passage closing member
42
. A float
47
is disposed in a float guide
46
of the frame
43
such that the float
47
is movable vertically and that the float
47
is supported by the center hole portion of a ring-shaped planar valve body
49
fitted with a valve body supporting portion
48
on the top end portion of the float
47
.
In the stop valve
41
provided with the aforementioned float
47
, if a fluid is likely to flow out upward through the opening
44
of the valve seat body
45
, the float
47
is pulled by the fluid toward the opening side, and thereby a surface
50
of the ring-shaped planar valve body
49
contacts with a ring-shaped sealing protrusion
51
formed on a bottom end portion in the circumference of the opening of the valve seat body
45
, thereby closing the opening
44
.
As shown in
FIG. 3B
, the valve body
49
is comprised of a rigid axial portion
52
which is fitted with the valve supporting portion
48
of the float
47
, and a ring-shaped planar bendable valve portion
53
which extends outward from the rigid axial portion
52
. The rigid axial portion
52
is formed thicker than the bendable valve portion
53
, therefore, even when the rigid axial portion
52
is located at the bottom end portion of the valve supporting portion
48
of the float
47
as shown in
FIG. 3B
, a gap d is provided in a usual condition between the back face of the bendable valve portion
53
and the top end face
54
of the float
47
.
In the valve body
49
of such a stop valve of float-actuating type having the aforementioned structure, when the valve is closed as mentioned above, the sealing protrusion
51
of the valve seat body
45
relatively pushes down the surface
50
of the valve body
49
by floating force of the float, thus the bendable valve portion
53
can be bent at least within the gap d and thereby the valve sealing is secured the same as in the valve body shown in FIG.
2
.
FIG. 4A
shows a stop valve of float-actuating type described above, provided with an improved valve body
55
. The valve body
55
has a float sealing portion
57
having three sealing lips as described in the figure, provided particularly on an inner circumference face of the rigid axial portion
56
.
FIG. 4B
shows a partially enlarged view of the valve body
55
installed on a float
58
. A center lip
59
located as the center of three sealing lips is formed thicker than other two lips while an upper lip
60
located above the center lip
59
in
FIG. 4B
is formed thinner than the center lip
59
. The upper lip
60
has the shape of a lower half part of the center lip in the example shown in
FIG. 4B
, therefore the upper lip
60
is a half of the center lip
59
in the thickness. Likewise, a lower lip
61
located under the center lip
59
in the figure has the shape of an upper half part of the center lip
59
thus is a half of the center lip
59
in thickness.
In a stop valve as shown in the aforementioned
FIG. 3
, a fluid tends to flow out through a gap between the valve body and the float. However, such flowing out can be prevented by forming a valve body into a three-lip shape which can seal the gap by each of the lips. This sealing structure can secure long-term sealing stability at the sealing portion.
To install the valve body of the stop valve, having the aforementioned sealing lips, onto the valve supporting portion
62
of the float
58
, a stopper portion
64
of the valve supporting portion
62
is fitted into a center opening
63
of the valve body. The stopper portion
64
is formed on the top end portion of the valve supporting portion
62
and is larger than the valve supporting portion
62
in diameter. In installation such as in automated machine assembly using jigs for example, the sealing lip may be installed in such a posture as the edge is bent due to the friction or other reasons. This may be caused because the edge of the upper lip
60
touches over the back face of the stopper portion
64
until the valve body is completely installed and the center opening
63
is attached onto a predetermined position shown in
FIG. 4B
, through the stopper portion
64
having a larger diameter as mentioned above.
In another example shown in
FIG. 4D
, the lower lip
61
may also be installed in such a posture as the edge of the sealing lip bent, not extended completely straight, due to the friction or other reasons that may be caused when the valve body is installed onto a predetermined position shown in
FIG. 4B
, because the edge of the lower lip
61
presses the surface of the valve supporting portion
62
by elastic force of the valve body, during the lower lip
61
is sliding on the surface of the valve supporting portion.
If the valve body is installed in such a posture as the edge of the sealing lip bent, a predetermined sealing performance each of the sealing lips should exert may not be achieved, and a defect product with bad sealing performance may happen. It would be required therefore to inspect installation failure after installation is finished, however it bothers a lot of time and labor.
Additionally, manual installation may be considered to eliminate such a failure caused in mechanical installation, however, in installing the valve body into such a proper posture as shown in
FIG. 4B
, a great deal of attention as well as sufficient experience is required, thereby causing product price increase.
The aforementioned problem may be
Fujimaki Takashi
Ishitoya Akihiro
Ito Ken-ichi
Kimura Kimiyasu
Kyosan Denki Co. Ltd.
Michalsky Gerald A.
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