Fluid handling – Systems – With flow control means for branched passages
Reexamination Certificate
2002-03-15
2004-07-27
Fox, John (Department: 3753)
Fluid handling
Systems
With flow control means for branched passages
C137S613000
Reexamination Certificate
active
06766829
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a valve assembly which is attached to a gas cylinder containing compressed gas or liquefied gas and is used for taking the gas out of the gas cylinder and charging it thereto. More specifically, it concerns a valve assembly with pressure reducing function, which makes it possible to take out high pressure gas within a gas cylinder as it is reduced to a desired low pressure when taking it out of the gas cylinder.
2. Explanation of Related Art
A conventional example of the valve assembly with pressure reducing function of this type is disclosed in U.S. Pat. No. 2,821,699 proposed earlier by an Assignee of the present invention.
The conventional valve assembly comprises a housing within which a gas inlet, a shut of f valve, a pressure reducing valve, a first check valve for retaining residual pressure and a gas outlet are arranged in series in the mentioned order. There is provided a bypass passage in parallel with the pressure reducing valve between an outlet of the shut off valve and the first check valve. The bypass passage is provided with a second check valve which inhibits a flow from the outlet of the shut off valve to the gas outlet. The pressure reducing valve has a piston which moves for opening and closing by a balance between a spring force for valve opening and a downstream pressure for valve closing.
The conventional valve assembly is excellent in that it can take out gas within a gas cylinder as its pressure is reduced by the pressure reducing valve when taking it out of the gas cylinder and besides in that it charges gas into a gas cylinder within a short period of time since it can charge the charging gas supplied to the gas outlet during the gas charging, into the gas cylinder via the bypass passage having a small flow resistance and a gap produced when the shut off valve opens. However, the conventional technique still has to be improved on the following points.
In the case where gas to be taken out must have its pressure largely reduced in comparison with that of high pressure gas within a gas cylinder, it is required to increase a pressure receiving area of the piston of the pressure reducing valve so as to smoothly move the piston for valve closing. In consequence, the conventional technique enlarges a diameter of the piston to entail a problem of making the valve assembly large and very heavy.
Further, when charging gas, the shut off valve has to be opened. Therefore, it takes labor to effect the opening operation. Also on this point, the conventional technique must be improved.
SUMMARY OF THE INVENTION
The present invention has an object to provide a valve assembly with pressure reducing function which is compact and facilitates the charging work.
In order to accomplish the foregoing object, the present invention has constructed a valve assembly in the following manner, for example, as shown in
FIGS. 1
to
4
,
FIG. 5
or
FIGS. 6 and 7
.
Within a housing
3
, a communication is provided between an inlet passage
11
and a shut off valve
12
and an outlet passage
13
and a gas outlet
5
in the mentioned order. Further, a bypass passage
14
and a charging port
6
communicates with each other within the housing
3
. The inlet passage
11
and the bypass passage
14
communicate with an interior space (A) of a gas cylinder
1
. A first pressure reducing valve
21
, a second pressure reducing valve
22
and a first check valve
31
for retaining residual pressure are arranged in the outlet passage
13
in series in the mentioned order from the shut off valve
12
toward the gas outlet
5
. The bypass passage
14
is provided with a second check valve
32
which inhibits a flow from the interior space (A) of the gas cylinder
1
to the charging port
6
.
The present invention functions in the following manner, for example, as shown in
FIGS. 1
to
4
.
When taking out gas, the shut-off valve
12
is opened. Then high pressure gas within the interior space (A) of the gas cylinder
1
is reduced to a predetermined middle pressure by the first pressure reducing valve
21
and subsequently is reduced to a desired low pressure by the second pressure reducing valve
22
. Thereafter, the low pressure gas is taken out of the gas outlet
5
through the first check valve
31
.
While taking out the gas, if reversely flowing gas invades the gas outlet
5
for any reason, the first check valve
31
inhibits the reverse flow to prevent an interior area of the gas cylinder
1
from being contaminated with the reversely flowing gas.
When the gas is continuously taken out until a residual pressure within the gas cylinder
1
lowers to a set pressure, a first check spring
90
automatically closes the first check valve
31
. This prevents further gas take-out to retain the residual pressure within the gas cylinder
1
at the set pressure.
When charging high pressure gas into the evacuated gas cylinder
1
, charging gas is supplied to the charging port
6
. Then the charging gas is charged into the gas cylinder
1
through the second check valve
32
of the bypass passage
14
.
Consequently, the present invention produces the following advantages.
The high pressure gas within the gas cylinder is reduced in multiple stages by a plurality of pressure reducing valves. This largely reduces a diameter of a pressure receiving member (piston, diaphragm and the like) of every pressure reducing valve when compared with a pressure reducing valve of single reduction type. This enables the plurality of pressure reducing valves to be readily installed in a redundant space within the housing, which results in preventing the projection of constituent members of these pressure reducing valves from the housing to thereby make the valve assembly compact and light. The foregoing construction could provide a compact valve assembly with pressure reducing function.
In the valve assembly, the bypass passage
14
is arranged in parallel with the shut off valve
12
. In this case, when charging the high pressure gas into the evacuated gas cylinder
1
, the charging gas is supplied to the charging port
6
with the shut off valve
12
kept closed. Then the charging gas is charged into the gas cylinder
1
through the second check valve
32
of the bypass passage
14
. This makes it unnecessary to open the shut off valve
12
when charging the gas, differently from the conventional technique. Further, it does not take much labor to charge the gas, which results in an easy gas charging.
In the valve assembly, the bypass passage
14
communicates with an inter-space between the shut off valve
12
and the first pressure reducing valve
21
of the outlet passage
13
. And a closing means (C) stops gas flow-out from the gas outlet
5
. The closing means (C) is provided downstream of a position where it communicates with the bypass passage
14
of the outlet passage
13
, or at the gas outlet
5
. In this case, after the closing means (C) has been closed, the shut off valve
12
is opened to supply the charging gas to the charging port
6
. Additionally, in the event that the second check valve
32
arranged in the bypass passage
14
has lost its checking function for any reason, the shut off valve
12
is closed. Then it is possible to prevent the gas within the gas cylinder
1
from being charged from the bypass passage
14
to an exterior area through the gas charging port
6
. As a result, even with the high pressure gas stored within the gas cylinder
1
, the second check valve
32
can be readily repaired or replaced.
The closing means (C) can be formed from at least one of the first pressure reducing valve
21
and the second pressure reducing valve
22
, for example, by making it have a set pressure on its downstream adjustable to ‘0’ (zero). Alternatively, the closing means (C) may be composed of a second shut off valve which is arranged at a halfway portion of the outlet passage
13
. In addition, the closing means (C) may be provided in a connector which is detachably attached to the gas outlet
5
.
In the
Hirakami Osamu
Maekawa Shinji
Takeda Masaru
Bacon & Thomas PLLC
Fox John
Kabushiki Kaisha Neriki
LandOfFree
Valve assembly for gas cylinder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Valve assembly for gas cylinder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Valve assembly for gas cylinder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3233479