U.S. patent application number 09/772984 was filed with the patent office on 2001-08-23 for sealing arrangement between flow regulator and shut-off valve attached to oxygen cylinder.
This patent application is currently assigned to TEIJIN LIMITED. Invention is credited to Okada, Katsuhiko, Yagi, Yutaka, Yoshida, Yoichi.
Application Number | 20010015419 09/772984 |
Document ID | / |
Family ID | 27342184 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015419 |
Kind Code |
A1 |
Yagi, Yutaka ; et
al. |
August 23, 2001 |
Sealing arrangement between flow regulator and shut-off valve
attached to oxygen cylinder
Abstract
The present invention provides a sealing arrangement between a
flow regulator and a shut-off valve attached to an oxygen cylinder.
The shut-off valve includes a casing which is adapted to be mounted
to an oxygen cylinder containing oxygen gas or an oxygen enhanced
gas, a side wall defining a part of the casing. A female outlet
port is defined in the side wall of the casing. The flow regulator
includes a metallic cylindrical body which has first and second end
faces. A yoke extends from the first end face of the cylindrical
body. A screw bolt, which has an end facing the first end face of
the cylindrical body, operates with the yoke to clamp the casing of
the shut-off valve between the first end face of the cylindrical
body and the end of the screw bolt. A male inlet port extends from
the first end face of the cylindrical body into the female outlet
port of the shut-off valve to receive the oxygen gas or the oxygen
enhanced gas. An o-ring is provided around the inlet port of the
flow regulator so that the o-ring is clamped between the first end
face of the cylindrical body of the flow regulator and the casing
of the shut-off valve when the flow regulator is secured to the
shut-off valve. The sealing member is made of an electrically
conductive rubber material.
Inventors: |
Yagi, Yutaka; (Iwakuni-shi,
JP) ; Okada, Katsuhiko; (Tokyo, JP) ; Yoshida,
Yoichi; (Tokyo, JP) |
Correspondence
Address: |
RADER FISHMAN & GRAUER PLLC
LION BUILDING
1233 20TH STREET N.W., SUITE 501
WASHINGTON
DC
20036
US
|
Assignee: |
TEIJIN LIMITED
|
Family ID: |
27342184 |
Appl. No.: |
09/772984 |
Filed: |
January 31, 2001 |
Current U.S.
Class: |
251/151 |
Current CPC
Class: |
F16K 1/308 20130101;
Y10S 277/919 20130101; Y10T 137/7833 20150401 |
Class at
Publication: |
251/151 |
International
Class: |
F16L 029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2000 |
JP |
2000-21594 |
Jan 31, 2000 |
JP |
2000-21595 |
Feb 3, 2000 |
JP |
2000-26010 |
Claims
We claim:
1. An arrangement for sealing between a flow regulator and a
shut-off valve attached to an oxygen cylinder, the shut-off valve
including a casing which is adapted to be mounted to an oxygen
cylinder containing oxygen gas or an oxygen enhanced gas, a side
wall defining a part of the casing, a female outlet port defined in
the side wall of the casing, the flow regulator including a
metallic cylindrical body having first and second end faces, a yoke
extending from the first end face of the cylindrical body, and a
screw bolt having an end facing the first end face of the
cylindrical body, the screw bolt operated with the yoke to clamp
the casing of the shut-off valve between the first end face of the
cylindrical body and the end of the screw bolt, the arrangement
comprising; a male inlet port, extending from the first end face of
the cylindrical body, for receiving the oxygen gas or the oxygen
enhanced gas from the outlet port of the shut-off valve when the
flow regulator is attached to the shut-off valve; and a sealing
member, provided around the inlet port of the flow regulator so
that the sealing member is clamped between the first end face of
the cylindrical body of the flow regulator and the casing of the
shut-off valve when the flow regulator is secured to the shut-off
valve, for sealing between the inlet port and the casing of the
shut-off valve around the outlet port, the sealing member being
made of an electrically conductive rubber material.
2. An arrangement according to claim 1, wherein the rubber material
has a volumetric resistivity of not more than 1.0.times.10.sup.10
.OMEGA.cm.
3. An arrangement according to claim 1, wherein the sealing member
comprises an o-ring provided around the inlet port; the arrangement
further comprising a metallic protection member, provided around
the o-ring, for protecting the o-ring from wear and tear; and the
o-ring being made of a rubber material having a volumetric
resistivity of not more than 1.0.times.10.sup.10 .OMEGA.cm.
4. An arrangement for sealing between a flow regulator and a
shut-off valve attached to an oxygen cylinder, the shut-off valve
including a casing which is adapted to be mounted to an oxygen
cylinder for containing oxygen gas or an oxygen enhanced gas, a
side wall defining a part of the casing, a female outlet port
defined in the side wall of the casing, and a positioning recess
defined in the side wall of the casing, the flow regulator
including a metallic cylindrical body having first and second end
faces, and a metallic positioning pin, extending from the first end
of the cylindrical body to engage the positioning recess of the
shut-off valve, a yoke extending from the first end of the
cylindrical body, and a screw bolt having an end facing the first
end of the cylindrical body, the screw bolt operated with the yoke
to clamp the casing of the shut-off valve between the first end
face of the cylindrical body and the end of the screw bolt, the
arrangement comprising; a male inlet port, extending from the first
end face of the cylindrical body, for receiving the oxygen gas or
the oxygen enhanced gas from the outlet port of the shut-off valve
when the flow regulator is attached to the shut-off valve; a
sealing member, provided around the inlet port of the flow
regulator so that the o-ring is clamped between the first end face
of the cylindrical body of the flow regulator and the casing of the
shut-off valve when the flow regulator is secured to the shut-off
valve, for sealing between the inlet port and the casing of the
shut-off valve around the outlet port; and a metallic protection
member, provided around the sealing member, for protecting the
sealing member from wear and tear, the metallic protection member
having a thickness which allows the metallic protection member to
contact the first end of the cylindrical body of the flow regulator
and/or the side wall of the shut-off valve.
5. An arrangement according to claim 4, wherein the thickness of
the metallic protection member is smaller than that of the sealing
member and larger than 80% of that of the sealing member.
6. An arrangement according to claim 5, wherein the sealing member
comprises an o-ring provided around the inlet port of the flow
regulator, and the metallic protection member comprises a
protection ring provided around the o-ring.
7. An arrangement according to claim 6, wherein the protection ring
includes an inner peripheral groove for snugly holding the
o-ring.
8. An arrangement according to claim 7, wherein the inner
peripheral groove of the protection ring has a rounded sectional
shape having a radius of curvature larger than that of the section
of the o-ring.
9. An arrangement according to claim 7, wherein the inner
peripheral groove of the protection ring has a polygonal sectional
shape.
10. An arrangement according to claim 4, wherein the sealing member
comprises an o-ring provided around the inlet port of the flow
regulator; and the metallic protection member comprising a
protection plate provided around the o-ring, the protection plate
including a positioning holes engaging the metallic positioning pin
of the flow regulator to provide an electric circuit for
discharging the static electricity charged in the o-ring.
11. An arrangement according to claim 4, wherein the sealing member
comprises an o-ring provided around the inlet port of the flow
regulator; the metallic protection member comprising a protection
ring provided around the o-ring; and the arrangement further
comprising a metallic clip provided around the protection ring, the
metallic clip including an arm portion engaging the metallic
positioning pin of the flow regulator to provide an electric
circuit for discharging the static electricity charged in the
o-ring.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a sealing arrangement for sealing
between a flow regulator and an oxygen cylinder.
[0003] 2. Description of the Related Art
[0004] In treatments for respiratory system diseases such as
pulmonary emphysema or chronic bronchitis, oxygen inhalation is
known as one of the most effective treatments. A small capacity
portable oxygen cylinder is generally used when a patient is out of
a hospital or his or her house. The oxygen cylinder contains high
pressure oxygen gas and is provided with a shut-off valve. A flow
regulator, for controlling the oxygen flow to the patient, is
connected to the shut-off valve with an o-ring or a sealing member
clamped therebetween. A metallic protection ring is provided around
the o-ring. When the oxygen gas contained in an oxygen cylinder is
exhausted or almost exhausted, the oxygen cylinder is replaced with
a new one. The shut-off valve is closed and the flow regulator is
detached from the shut-off valve. At that time, if the on-off valve
is closed, a substantial volume of oxygen gas, which is filled
within the flow regulator, blows out of it when the flow regulator
is detached from the shut-off valve of the oxygen cylinder.
Detachment of the flow regulator deforms the o-ring clamped between
the flow regulator and the shut-off valve which results in
electrostatic charge in the o-ring. The static electricity charged
in the o-ring induces electric potential in the metallic protection
ring relative to the shut-off valve and the flow regulator. A spark
may be generated between the metallic protection ring and the
shut-off valve and/or the flow regulator when the o-ring is apart
from the shut-off valve, which may result in an accidental fire if
there is combustible material near the oxygen cylinder.
SUMMARY OF THE INVENTION
[0005] The invention is directed to solve the prior art problems,
and to provide an arrangement for sealing the connection between a
shut-off valve attached to an oxygen cylinder and a flow regulator,
which arrangement is prevented from an accidental fire due to the
discharge of the oxygen gas or oxygen enhanced gas which has been
filled in the flow regulator.
[0006] According to one feature of the present invention, there is
provided an arrangement for sealing between a flow regulator and a
shut-off valve attached to an oxygen cylinder. The shut-off valve
includes a casing which is adapted to be mounted to an oxygen
cylinder containing oxygen gas or an oxygen enhanced gas, a side
wall defining a part of the casing. A female outlet port is defined
in the side wall of the casing. The flow regulator includes a
metallic cylindrical body which has first and second end faces. A
yoke extends from the first end face of the cylindrical body. A
screw bolt, which has an end facing the first end face of the
cylindrical body, operates with the yoke to clamp the casing of the
shut-off valve between the first end face of the cylindrical body
and the end of the screw bolt. A male inlet port extends from the
first end face of the cylindrical body into the female outlet port
of the shut-off valve to receive the oxygen gas or the oxygen
enhanced gas. A sealing member is provided around the inlet port of
the flow regulator so that the o-ring is clamped between the first
end face of the cylindrical body of the flow regulator and the
casing of the shut-off valve when the flow regulator is secured to
the shut-off valve. The sealing member is made of an electrically
conductive rubber material.
[0007] The sealing member may be an o-ring provided around the
inlet port, and a metallic protection member is provided around the
o-ring for protecting the o-ring from wear and tear. According to
one embodiment, the rubber material preferably has a volumetric
resistivity of not more than 1.0.times.10.sup.10 .OMEGA.cm.
[0008] According to another feature of the invention, an
arrangement for sealing between a flow regulator and a shut-off
valve attached to an oxygen cylinder is provided. The shut-off
valve includes a casing which is adapted to be mounted to an oxygen
cylinder containing oxygen gas or an oxygen enhanced gas. A female
outlet and a positioning recess port are defined in the side wall
of the casing. The flow regulator includes a metallic cylindrical
body which has first and second end faces. A metallic positioning
pin extends from the first end of the cylindrical body to engage
the positioning recess of the shut-off valve. A yoke extends from
the first end of the cylindrical body. A screw bolt, which has an
end facing the first end of the cylindrical body, operates with the
yoke to clamp the casing of the shut-off valve between the first
end face of the cylindrical body and the end of the screw bolt. A
male inlet port extends from the first end face of the cylindrical
body into the outlet port of the shut-off valve when the flow
regulator is attached to the shut-off valve. A sealing member is
provided around the inlet port of the flow regulator so that the
sealing member is clamped between the first end face of the
cylindrical body of the flow regulator and the casing of the
shut-off valve when the flow regulator is secured to the shut-off
valve. A metallic protection member for protecting the sealing
member from wear and tear is provided around the sealing member.
The metallic protection member has a thickness which allows the
metallic protection member to contact the first end of the
cylindrical body of the flow regulator and/or the side wall of the
shut-off valve.
[0009] The thickness of the metallic protection member is
preferably smaller than that of the sealing member and larger than
80% of that of the sealing member. According to an embodiment of
the invention, the sealing member may comprise an o-ring provided
around the inlet port of the flow regulator, and the metallic
protection member comprises a protection ring provided around the
o-ring. In this case, the thickness of the sealing member is
defined by the diameter of the o-ring. The protection ring may
include an inner peripheral groove for snugly holding the o-ring.
The inner peripheral groove of the protection ring may have a
rounded sectional shape having a radius of curvature larger than
that of the section of the o-ring or a polygonal sectional
shape.
[0010] According to another embodiment of the invention, the
metallic protection member comprises a protection plate provided
around the o-ring. The protection plate includes a positioning hole
engaging the metallic positioning pin of the flow regulator to
provide an electric circuit for discharging the static electricity
charged in the o-ring.
[0011] According to another embodiment of the invention, the
metallic protection member comprises a protection ring provided
around the o-ring. A metallic clip is provided around the
protection ring. The metallic clip includes an arm portion engaging
the metallic positioning pin of the flow regulator to provide an
electric circuit for discharging the static electricity charged in
the o-ring.
DESCRIPTION OF THE DRAWINGS
[0012] These and other objects and advantages and a further
description will now be discussed in connection with the drawings
in which:
[0013] FIG. 1 is a partially sectional illustration of an
arrangement of the invention for sealing between a shut-off valve
attached to an oxygen cylinder and a flow regulator attached to the
shut-off valve;
[0014] FIG. 2 is a perspective view of the oxygen cylinder, the
shut-off valve and the flow regulator;
[0015] FIG. 3A is an enlarged section of the sealing arrangement
according to an embodiment of the invention when a screw bolt of a
yoke type clamping means of the flow regulator is not
tightened;
[0016] FIG. 3B is an enlarged section similar to FIG. 3A in which
the screw bolt is tightened;
[0017] FIG. 4A is a partially sectional perspective view which
shows a portion of a protection ring according to an embodiment of
the invention;
[0018] FIG. 4B is a partially sectional perspective view which
shows a portion of a protection ring according to another
embodiment of the invention FIG. 5A is a front view of the sealing
arrangement of an embodiment of the invention along line V-V in
FIG. 5B;
[0019] FIG. 5B is a section of the sealing arrangement of FIG.
5A;
[0020] FIG. 6A is a front view of the sealing arrangement of
another embodiment of the invention along line VI-VI in FIG.
6B;
[0021] FIG. 6B is a section of the sealing arrangement of FIG.
6A;
[0022] FIG. 7A is a front view of the sealing arrangement of
another embodiment of the invention along line VII-VII in FIG.
7B;
[0023] FIG. 7B is a side view of the sealing arrangement of FIG.
7A;
[0024] FIG. 7C is a section of a protection ring of the embodiment
shown in FIGS. 7A and 7B;
[0025] FIG. 8 is front view of a clip according to an embodiment of
the invention;
[0026] FIG. 9A is a section, similar to FIG. 3A, of the sealing
arrangement according to a prior art; and
[0027] FIG. 9B is an enlarged section, similar to FIG. 3B, of the
sealing arrangement according to a prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] FIGS. 1 and 2 show an oxygen cylinder 100 which contains
high pressure oxygen gas or an oxygen enhanced gas. The oxygen
cylinder is provided with a shut-off valve 102 which is adapted to
CGA (Compressed Gas Association) 870. The shut-off valve 102
includes a casing 104 for accommodating a valve body (not shown)
movable between an open position and a closed position, a cock 105
for manipulating the valve body between the open and closed
positions and a pressure gage 103 for indicating the pressure in
the oxygen cylinder 100. A side wall 106 of the casing 104 includes
a pair of positioning recesses 106a for positioning a flow
regulator 110 which is attached to the shut-off valve 102. The side
wall 106 further includes a outlet port 106b for discharging the
oxygen gas when the valve body is in the open position.
[0029] The flow regulator 110 includes a cylindrical body 112
having first and second end faces 112a and 112b. An inlet port 114
and a pair of positioning pins 124 extend from the first end face
112a so as to be inserted into the outlet port 106b and the
positioning recesses 106a of the shut-off valve 102, respectively,
when the flow regulator 110 is attached to the shut-off valve 102.
The positioning pins 124 are generally made of a metallic material
and, in particular, are made of a stainless steel. The engagement
between the metallic positioning pins 124 and the positioning
recesses 106a displaces the flow regulator 110 in place relative to
the shut-off valve 102. An outlet port 118 is connected to the
cylindrical body 112 adjacent the second end face 112b. A yoke 116
is connected to the first end face 112a of the cylindrical body
112. The yoke 116 has a threaded hole 116a with which a screw bolt
120 engages, as shown in FIG. 1. Tightening the screw bolt 120
clamps the shut-off valve 102 between the end 120a of the screw
bolt 120 and the first end face 112a of the cylinder body 112 to
secure the flow regulator 110 to the shut-off valve 102.
[0030] The outlet port 118 is adapted to be fluidly connected,
through a conduit or a tube (not shown), to a nasal cannula or a
nasal mask (not shown) which is attached to the nose of the
patient. An aspiration sensor (not shown) is provided for detecting
the aspiration of the patient. The cylindrical body 112 of the flow
regulator 110 contains an on-off valve (not shown) which is fluidly
connected to the inlet and outlet ports 114 and 118 and operates to
fluidly connect and disconnect the inlet and outlet ports 114 and
118 so that the oxygen gas or the oxygen enhanced gas is supplied
to the respiratory system of the patient only when an aspiration of
the patient is detected by the aspiration sensor.
[0031] Referring to FIGS. 3A and 3B, when the flow regulator 110 is
attached to the shut-off valve 102, the inlet port 114 is inserted
into the outlet port 106a of the shut-off valve 102, as shown in
FIG. 3A. Provided around the inlet port 114 of the flow regulator
110 is a sealing member, in this particular embodiment an o-ring
122 which is clamped between the first end face 112a of the
cylindrical body 112 and the side wall 106 of the shut-off valve
102 to seal between the flow regulator 110 and the shut-off valve
102. According to a feature of the invention, the o-ring 122 can
preferably be made of an electrically conductive rubber material
which has a volumetric resistivity of not more than
1.0.times.10.sup.10 .OMEGA.cm, preferably not more than
1.0.times.10.sup.7 .OMEGA.cm, and more preferably not more than
1.0.times.10.sup.6 .OMEGA.cm, for example a fluorocarbon elastomer
in which carbon particles are added, as a conductive material, to
enhance the conductivity or a chloroprene rubber material. The
small volumetric resistivity or the conductivity of the o-ring 122
allows the static electricity charged in the o-ring 122 to be
discharged directly to the cylindrical body 112 of the flow
regulator 110 and the shut-off valve 102. Therefore, in case the
case that the o-ring 122 is made of electrically conductive rubber
material, the metallic protection member can be replaced with a
protection member made of a high-strength engineering plastic
material.
[0032] An experiment was executed to measure the static electric
voltage induced in the protection ring 10, in which three type of
o-rings were used. The o-rings were made of poly (vinylidene
fluoride-hexafluoropropyl- ene), available as Viton from DuPont
(Example 1); Viton base carbon enhanced fluorocarbon elastomer
(Example 2); and chloroprene (Example 3), respectively. The
experiment results were shown in Table 1.
1 TABLE 1 Volumetric Resistivity Static (.OMEGA.cm) Electricity
(Method of Measurement) (V) Example 1 2.5 .times. 10.sup.13 (JIS
K6911) 500 Example 2 Less Than 1.0 .times. 10.sup.6 (JIS 0 K6911)
6.2 (SRIS 2301) Example 3 1.2 .times. 10.sup.7 (JIS K6911) 0
[0033] In the experiment, the volumetric resistivity was measured
in accordance with JIS K6911 (Ambient temperature 23.degree. C.;
relative humidity 50%). In this connection, according to JIS K6911,
the static electricity induced in the protection ring could not
measured in the case of Example 2 because the static electricity
was below the lower measurable limit. Therefore, the measurement
was carried out in accordance with SRIS 2301 for Example 2.
[0034] A metallic protection member, made of brass material, steel
material, or aluminum material, is provided around the o-ring 122.
In an preferred embodiment, the protection member comprises a
protection ring 10. The protection ring 10 preferably has a
thickness T which is smaller than the diameter D of the section of
the o-ring 122 so that the o-ring can contact both the first end
face 112a of the cylinder body 112 of the flow regulator 110 and
the side wall 106 of the shut-off valve 102 to provide a sealing
effect. The thickness T must be sufficient to allow the protection
ring 10 to contact the first end face 112a of the cylinder body 112
of the flow regulator 110 and the side wall 106 of the shut-off
valve 102, as shown in FIG. 3B, when the screw bolt 120 is
tightened to attach the flow regulator 110 to the shut-off valve.
This allows the protection ring 10 to be grounded to the
cylindrical body 112 of the flow regulator 110 and/or the shut-off
valve 102 so that the electric potential induced in the protection
ring 10 relative to the flow regulator 110 and the shut-off valve
102 by the static electricity charged in the o-ring 122 is reduced.
An experiment shows that a thickness T of the protection ring 10
larger than 80% of the thickness of the sealing member or the
diameter D of the o-ring 122 allows the protection ring 10 to
contact the first end face 112a of the cylinder body 112 of the
flow regulator 110 and the side wall 106 of the shut-off valve 102.
FIGS. 9A and 9B show a prior art, in which an insufficient
thickness T' of the protection ring 10' prevents the protection
ring 10' from contacting the cylindrical body 112 of the flow
regulator 110 or the casing 104 of the shut-off valve 102.
[0035] With reference to FIG. 4A, the protection ring 10 includes
an inner peripheral groove 10a for snugly holding the o-ring 122.
The inner peripheral groove 10a has a rounded section, as shown
FIG. 4A. However, the shape of the inner peripheral groove is not
limited to this and may be formed into a polygonal shape, for
example a trapezoid shape, as shown by reference "12", in FIG.
4B.
[0036] In the previous embodiments, the protection member is formed
into a ring. However, the present invention is not limited to this
configuration.
[0037] With reference to FIGS. 5A and 5B, a modified embodiment of
the protection member is shown. In the embodiment shown in FIG. 5A,
the protection member comprises a protection plate 20 which
includes a central hole 22 for receiving the o-ring 122 and a pair
of positioning holes 24 for receiving the metallic positioning pins
124. Engagement between the metallic positioning pins 124 and the
positioning holes 24 displaces the protection plate 20 relative to
the flow regulator 110 and the shut-off valve 102. Engagement
therebetween further provides a ground circuit for the protection
plate 20 to the flow regulator 110 and the shut-off valve 102
through the metallic positioning pins 124. The electric potential
induced in the protection plate 20 relative to the flow regulator
110 and the shut-off valve 102 by the static electricity charged in
the o-ring 122 is reduced through the ground circuit. This
configuration is advantageous when the cylindrical body 112 of the
flow regulator 110 and/or the shut-off valve 102 is a made of
non-electrically-conductive material. In particular, when the
cylindrical body 112 of the flow regulator 110 and/or the shut-off
valve 102 is made of aluminum material, their surfaces are often
coated by an aluminum oxide which prevents the conductivity of the
cylindrical body 112 of the flow regulator 110 and/or the shut-off
valve 102. Even in that case, the ground circuit provided by the
engagement between the positioning holes 24 and the metallic
positioning pins 124 reduces the electric potential induced in the
protection plate 20. Therefore, a spark is prevented when the flow
regulator 110 is detached from the shut-off valve 102. In this
connection, according to this embodiment, the thickness of the
protection plate 20 must be smaller than that of the o-ring 122,
however, it is not required to be larger than 80% of that of the
o-ring 122.
[0038] In an embodiment shown in FIGS. 6A and 6B, the protection
member comprises a protection plate 30. The protection plate 30
includes a central hole 32 for receiving the o-ring 122 and a pair
of positioning holes 34 for receiving the metallic positioning pins
124. Engagement between the metallic positioning pins 124 and the
positioning holes 34 displaces the protection plate 30 and provides
an electric circuit for discharging the static electricity charged
in the o-ring 122 from the o-ring 122 to the flow regulator 110 and
the shut-off valve 102 through the protection plate 30 and the
metallic positioning pins 124. In this connection, according to
this embodiment, the thickness of the protection plate 30 must be
also smaller than that of the o-ring 122, however, it is not
required to be larger than 80% of that of the o-ring 122.
[0039] FIGS. 7A-7C show another embodiment of the protection
member. In this embodiment, the protection member comprises a
protection ring 40. The protection ring 40 includes an inner
peripheral grove 40a for snugly holding the o-ring 122 and a outer
peripheral groove 40b for engagement with a metallic clip 42. The
metallic clip 42 are preferably made of a stainless steel spring
material, and includes arm portions 42a which are adapted to engage
the metallic positioning pins 124. According to this embodiment,
engagement between the arm portions 42a and the metallic
positioning pins 124 displaces the protection ring 40 and provides
a ground circuit for the protection ring 40 to the flow regulator
110 and the shut-off valve 102 through the metallic clip 42 and the
positioning pins 124. In this connection, according to this
embodiment, the thickness of the protection ring 40 must be also
smaller than that of the o-ring 122, however, it is not required to
be larger than 80% of that of the o-ring 122.
[0040] FIG. 8 shows another embodiment, in which the metallic clip
42 is replaced with a metallic clip 50. The metallic clip 50 has a
pair of arm portions 52 which are adapted to be rounded around the
metallic positioning pins 24 when the metallic clip 50 is assembled
to the flow regulator 110.
[0041] It will also be understood by those skilled in the art that
the forgoing description is a preferred embodiment of the disclosed
device and that various changes and modifications may be made
without departing from the spirit and scope of the invention.
* * * * *