Valve structure

A gas cylinder valve assembly has an outside portion positioned outside the gas cylinder and an inside portion positioned inside the gas cylinder. A canal for conducting gas passes through the inside and outside portions. The canal communicates with the inside of the cylinder through orifices in the inside portion. The canal further communicates with the inside of the gas cylinder through an opening, gas flow through which is controlled by a check valve. The check valve normally closes the opening. Gas in the cylinder flows to the outside through the orifices. During the filling operation, gas is supplied from outside under pressure. The gas under pressure opens the check valve, and gas flows both through the orifices and through the opening.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to valve structures, and more particularly to valve 
structures for use with storage devices for pressurized gases or liquids. 
2. Description of Related Art 
Valve assemblies are used with storage devices for storing gas or liquid 
under pressure. Valve assemblies regulate the flow of gas or liquid in and 
out of the storage device. Many valve assemblies have safety features that 
minimize risk to the valve assembly operator in case of damage to the 
assembly. FIGS. 1 and 2 show a gas cylinder 10 and a prior art valve 
assembly 40. Gas cylinder 10 normally stores gas under pressure. Valve 
assembly 40 has a canal 70 for releasing gas from cylinder 10 and for 
filling cylinder 10. Canal 70 is opened and closed by an angle globe valve 
64. An operator operates valve 64 by turning handwheel 62. 
Nozzle 50 of valve assembly 40 has protrusion 54 which defines a relatively 
narrow orifice 56 limiting the flow area through canal 70. Even if valve 
64 is fully open, orifice 56 restricts the gas flow and thus makes the 
valve assembly operation safer for the operator. 
Valve assembly 40 has certain shortcomings. If the relatively narrow 
orifice 56 gets plugged, gas cannot be released from gas cylinder 10. 
Furthermore, gas cylinder 10 is purged before being replaced. If orifice 
56 is plugged, gas gets trapped inside cylinder 10. The trapped gas makes 
gas cylinder changing dangerous. 
To refill gas cylinder 10, valve 64 is opened and gas is supplied under 
pressure from outside through canal 70. Orifice 56 restricts the gas flow 
and so makes filling several times longer. 
Also, if valve assembly 40 is accidentally sheared off cylinder 10, the gas 
is released from cylinder 10 at a high rate thus placing the operator at 
risk. 
It is desirable to provide a safe and fully functional valve assembly 
without the foregoing shortcomings. 
SUMMARY OF THE INVENTION 
When used with storage devices such as gas cylinders, the valve assembly of 
my invention functions by allowing fast filling of the storage device 
while providing for a limited discharge of gas during normal operation. 
The valve assembly reduces the chances of having gas trapped during 
purging. The valve assembly safety features reduce the risk to the 
operator in case when the portion of the assembly outside the cylinder is 
sheared off. 
According to this invention, a valve assembly has a body adapted for being 
mounted in a wall of a vessel. The body has a first portion to be 
positioned inside a vessel and a second portion to be positioned outside 
the vessel and above the first portion. A canal extends through the first 
and second portions. The canal has an opening in the first portion and a 
part above the opening. That part communicates with an inside of the 
vessel through one or more orifices. The assembly further has a check 
valve seated against the opening. The check valve opens the opening when a 
matter like gas goes down through the canal under a predetermined 
pressure. 
According to another aspect of the present invention, a valve assembly has 
a canal therethrough, the canal has a first end and a second end. An 
orifice passes from the canal outside the assembly. The orifice has an 
opening into the canal between the first and second ends. A check valve 
restricts the flow of matter through the second end towards the first end. 
The check valve allows the free flow of matter from the first end through 
the second end when the matter is supplied under a predetermined pressure. 
According to another aspect of the present invention, an apparatus is 
provided for conducting a matter between a first region and a second 
region, the first region having a first pressure and the second region 
having a second pressure. The apparatus has a body having a first path 
therethrough for conducting a matter between the two regions, and a second 
path therethrough for conducting a matter between the two regions. The 
apparatus further has a check valve in the second path. The check valve 
opens the second path only when the second pressure exceeds the first 
pressure by a predetermined amount. 
According to another aspect of the present invention, a valve assembly 
comprises a body member adapted to be mounted in a wall of a vessel with a 
first body portion inside of the vessel and the second body portion 
outside the vessel. A first canal extends from an orifice on the exterior 
of the second body portion through the body member to a terminus. A second 
canal extends from an orifice on the exterior of the first body portion to 
the first canal. The smallest cross sectional area of the second canal is 
less than the smallest cross sectional area of the first canal. A check 
valve is provided having an inlet communicating with the terminus of the 
first canal and an outlet.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 3 shows a valve assembly 140 suitable for use with a vessel or gas 
cylinder 10 for storing gas or liquid under pressure. 
Valve assembly 140 includes a body 92 which has outside threads 94 formed 
between a first body portion 93 and a second body portion 95. Valve 
assembly 140 is mounted to gas cylinder 10 by means of threads 94 which 
mate with similar threads on gas cylinder 10. When valve assembly 140 is 
connected to gas cylinder 10, first body portion 93 is located inside of 
gas cylinder 10 and second body portion 95 is located outside of gas 
cylinder 10. 
A first canal 70 extends through body 92 from a first opening 71 located at 
a first end of second body portion 95 to a second opening (terminus) 72 
located at a second end of first body portion 93. First canal 70 provides 
a gas flow passage between an inside (first) region 14 located inside of 
cylinder 10 and outside of body 92, and an outside (second) region 15 
located outside of cylinder 10 and body 92. First canal 70 communicates 
with, but is distinguished from, inside region 14 and outside region 15. 
Orifices 96a and 96b are formed in a wall of first body portion 93 which 
provides permanently-open second canals directly between inside region 14 
of gas cylinder 10 and a part 73 of canal 70. FIG. 4 shows a top view of 
the cross-section taken along lines FIG. 4--FIG. 4 through orifices 96a 
and 96b. The second canals formed by orifices 96a and 96b have cross 
sectional areas which a smaller than a cross sectional area of first canal 
70. 
A valve 64 is located in second body portion 95 and disposed to adjustably 
block gas flow along first canal 70. If the gas pressure of inside region 
14 is greater than the gas pressure of outside region 15 and valve 64 is 
opened, then gas flows along a first path from inside region 14 of gas 
cylinder 10 through orifices 96a and 96b, through first canal 70, past 
open valve 64, and out first opening 71 to outside region 15. Note that 
the second canals defined by orifices 96a and 96b provide a direct passage 
between inside region 14 and part 73 of first canal 70 when valve 64 is in 
either an open position or a closed (flow blocking) position. Therefore, 
if second body portion 95 and valve 64 are broken or sheared from first 
body portion 93, then orifices 96a and 96b allow a restricted flow of gas 
to exit cylinder 10. Because the rate of gas flow is restricted when valve 
64 is sheared off, the risk of injury to the operator is reduced. Further, 
because the gas is able to escape through orifices 96a and 96b, gas is not 
trapped in gas cylinder 10. 
Valve assembly 140 further includes a spring-assisted ball seated check 
valve 100 for adjustably blocking gas flow between first canal 70 and 
inside region 14 through second opening 72. Check valve 100 comprising a 
ball 102 and a spring 104. Spring 104 is mounted in a cup 108. Cup 108 
includes exterior threads which mate with similar threads formed in body 
92. A top view of check valve 100 along line FIG. 5--FIG. 5 of FIG. 3 is 
shown in FIG. 5. Preset loading on spring 104 forces ball 102 upward to 
close second opening 72 of canal 70. Preset loading in the range rom 15 
lbs to 100 lbs is suitable. 
During a refill operation, valve 64 is opened and gas pressure of the 
outside region 15 is made greater than the gas pressure of inside region 
14 of gas cylinder 10. This causes gas to flow along the first path from 
outside region 15 through first opening 71, through open valve 64 and 
through orifices 96a and 96b into inside region 14 of gas cylinder 10. 
Note that gas flow into inside region 14 is restricted by orifices 96a and 
96b. In addition to flow along the first path, gas pressure creates a 
force on check valve 100 which forces ball 102 to compress spring 104, 
thereby forcing ball 102 away from second opening 72. This creates a 
second gas flow path from outside region 15 through first opening 71, 
through open valve 64 and through second opening 72 and large openings 
106a through 106d into inside region 14 of gas cylinder 10. Note that the 
first and second flow paths include a common portion from first opening 71 
to the part 73 of first canal 70 adjacent orifices 96a and 96b. During the 
refill operation, most of the gas flows along the second path because 
second opening 72 and large openings 106a through 106d, which are formed 
on body 92, are substantially larger than orifices 96a and 96b. Therefore, 
less gas flow restriction occurs along the second path than along the 
first path, thereby facilitating fast refill operations. 
Valve assembly 140 thus allows fast refill operation while orifices 96a and 
96b provide the safety feature of restricting the outflow of gas from 
inside region 14 if second body portion 95 is sheared off from cylinder 
10. Because valve 64 blocks a portion of first canal 70 between first 
opening 71 and orifices 96a and 96b, orifices 96a and 96b are not easily 
plugged b external dirt. Furthermore, if one orifice 96a and 96b is 
plugged, gas flows through the other. In particular, gas is unlikely to be 
trapped in gas cylinder 10 during purging. Thus gas cylinder replacement 
is safer. 
While my invention has been described in terms of the embodiments and 
variations set forth above, it is not to be considered limited to these 
embodiments and variations. For example, more than two orifices may be 
provided; only one orifice is sufficient. Orifices 96 do not have to 
extend horizontally, and may have other shapes and directions. Check valve 
100 may have other constructions than the spring-assisted ball seated 
valve described above. Valve 64 may be implemented in many ways. Opening 
106 may be of many shapes and configurations. Valve assembly 140 can be 
used with gas tanks and other vessels differing from gas cylinder 10 in 
numerous ways. Valve assembly 140 can regulate the flow of liquid rather 
than gas, or of gas which is liquified under pressure inside the vessel. 
The scope of my invention is defined by the following claims.