GB2300692A

GB2300692A - Valve assembly for gas cylinder

Info

Publication number: GB2300692A
Application number: GB9603404A
Authority: GB
Inventors: Mitsunori Sakai; Masakatsu Kawahara; Teruo Hatori
Original assignee: Neriki KK
Current assignee: Neriki KK
Priority date: 1995-05-09
Filing date: 1996-02-19
Publication date: 1996-11-13
Anticipated expiration: 2016-02-19
Also published as: JPH08303695A; FR2734041A1; GB9603404D0; FR2734041B1; GB2300692B

Abstract

A flow control valve assembly for a gas cylinder containing gas under pressure comprises a first adjustable valve 11 between the gas inlet 4 and the gas outlet 5 and a second pressure responsive valve 12 in the outlet passage, the second valve having an axis which does not intersect the axis of the first valve. The second valve comprises a pressure chamber 30 which ensures that the valve remains open against the force of spring 28 until pressure drops to a predetermined value. A passageway 33 (Figure 3) communicates between the spring compartment and the atmosphere and can be provided with a filter 36. The invention provides a readily refillable gas cylinder and is designed so that the valves and hence the cylinder contents are not contaminated from the outside.

Description

VALVE ASSEMBLY FOR GAS CYLINDER Background of the Invention The present invention relates to a valve assembly which is attached to a gas cylinder containing a compressed gas or a liquefied gas for use in taking out and charging the gas.

Conventionally, there has been a valve assembly for gas cylinder recited in U.S.P.

4,210,168 as one of the valve assemblies of this kind. This is a technique previously proposed by the present Applicant and constituted as follows.

A first valve for closing is provided within a valve casing at a halfway height portion thereof. An outlet nozzle is projected sideways in such a state that its axis intersects a first valve chamber of the first valve. A second valve for responding to pressure is disposed within the outlet nozzle. Hermetically inserted into a second valve chamber of the second valve is a second valve member made of a stepped cylinder.

The above-mentioned conventional valve assembly operates as follows.

When a gas is taken out, the first valve is opened. Then the second valve member is opened by the pressure of the gas flowed into the first valve chamber of the first valve to flow the gas out of a gas outlet of the outlet nozzle.

Conversely, when the gas is consumed and then a new gas is charged into the evacuated gas cylinder, a gas charging mouthpiece is connected to the gas outlet and a valve opening member provided in the charging mouthpiece pushes the second valve member to forcibly open it.

By the way, the valve assembly of the conventional construction causes the following problems when it is used under the environment where there exist in the atmosphere especially lots of foreign matters such as dust, salinity or the like.

More specifically, if the foreign matters existing in the atmosphere adhere to the valve opening member while the gas charging mouthpiece is being stocked or at the time of commencing its use, those foreign matters easily enter into the second valve chamber through a bore of the second valve member made of the cylinder when such gas charging mouthpiece is connected to the outlet nozzle of the valve casing. Accordingly, there is a likelihood that the second valve member fails to operate due to the entered foreign matters.

Further, the outlet nozzle of the conventional construction is largely projected sideways from the valve casing since it houses the second valve. Consequently, there is a problem that the sideways dimension of the valve assembly is large.

Summary of the Invention An object of the present invention is to provide a valve assembly which can prevent the second valve member for responding to pressure from failing to operate and besides be made compact.

In order to accomplish the foregoing object, for example, as shown in Figs. 1 and 2 or in either of Figs. 3 and 4, the present invention constitutes the valve assembly for gas cylinder as follows.

An inlet passage 7, a first valve 11 for closing and an outlet passage 8 are provided in order between a gas inlet 4 and a gas outlet 5 within a valve casing 3. Disposed at a halfway portion of the outlet passage 8 is a second valve 12 for responding to pressure. An outlet nozzle 3b having the outlet passage 8 arranged therein is swelled out of a peripheral wall of a first valve chamber 15 of the first valve 11 into the external space of the valve casing 3 in such a state that its axis does not substantially intersect an axis of the first valve chamber 15. The second valve 12 is arranged within the swelled out outlet nozzle 3b.A pressurizing chamber 30 for opening valve, which is communicated with the first valve chamber 15, is provided on an outer periphery of a second valve member 25 to be hermetically inserted into a second valve chamber 21 of the second valve 12 and urged toward a second valve seat 20 by a valve closing spring 28. A communication passage 33 for communicating the second valve chamber 21 with the external space of the valve casing 3 is provided in a peripheral wall of the second valve chamber 21.

The present invention operates in the following manner, for example, as shown in Figs. 1 and 2.

When a gas is taken out, a gas taking-out mouthpiece (not shown) is connected to the gas outlet 5. In this state the first valve 11 is opened. Then a high pressure gas within a gas cylinder 1 is flowed through the first valve chamber 15 into the pressurizing chamber 30 to space the second valve member 25 apart from the second valve seat 20 against the valve closing spring 28 by the pressure of the flowed-in gas, whereby the gas is taken out of the gas outlet 5.

When the gas is continuously taken out until an inner pressure of the gas cylinder 1 lowers to a set value, the second valve member 25 is automatically closed by the spring 28. This prevents the gas from being further taken out to thereby retain the inner pressure of the gas cylinder 1 at a predetermined pressure. As a result, even if the first valve 11 is kept open by mistake, it is possible to prohibit the atmosphere from invading into the evacuated gas cylinder 1.

When a new high pressure gas is charged into the evacuated gas cylinder 1, a gas charging mouthpiece (not shown) is connected to the gas outlet 5 and the gas is supplied into the outlet passage 8 from the gas charging mouthpiece with the first valve 11 kept open. Then the pressure of the supplied gas spaces the second valve member 25 apart from the second valve seat 20 against the spring 28, whereby the gas is charged from the gas outlet 5 into an inner space (A) of the gas cylinder 1 through a hole of the second valve seat 20, the pressurizing chamber 30, the first valve chamber 15, the inlet passage 7 and the gas inlet 4 in order The present invention brings about the following advantages owing to the fact that it is constituted and operates as mentioned above.

When charging a gas, it being possible to open the second valve member for responding to pressure by the pressure of the gas to be charged, the valve opening member can be omitted from the gas charging mouthpiece. Therefore, differently from the above-mentioned conventional construction, the present invention can prevent the dust, salinity or like'foreign matters adhered to the valve opening member from invading into the gas outlet.

In addition, unlike the conventional construction, the second valve member of the present invention dispenses with the provision of a cylindrical bore for communicating the gas outlet with the second valve chamber. Therefore, should the foreign matters invade into the gas outlet, it is possible to prohibit the invasion of those foreign matters from the gas outlet into the second valve chamber.

Owing to the above fact, the second valve member can be prevented from failing to operate.

Since the outlet nozzle housing the second valve is swelled out of the peripheral wall of the first valve chamber for closing into the external space of the valve casing in such a state that its axis does not substantially intersect the axis of the first valve chamber, the length by which the outlet nozzle is projected from the valve casing is reduced when compared with the valve assembly of the conventional construction. Besides, the provision of the second valve chamber of the second valve around the first valve chamber reduces the height of the valve casing.

Owing to the above fact, the valve assembly can be made compact.

Moreover, the second valve provided within the outlet nozzle is so constructed that it suffices if the pressurizing chamber is provided on the outer periphery of the second valve member hermetically inserted into the second valve chamber and the second valve chamber is communicated with the external space of the valve casing by the communication passage. Accordingly, there is no necessity to add any new member, which can simplify the construction of the valve assembly.

Brief Description of the Drawings Fig. 1 shows an embodiment of a valve assembly according to the present invention and is a partial sectional view when seen from the left side surface of Fig. 2.

Fig. 2 is a vertical sectional view of the valve assembly.

Fig. 3 shows a first modification of the valve assembly and is a partial view corresponding to the Fig. 1.

Fig. 4 shows a second modification of the valve assembly and is a partial view corresponding to the Fig. 1.

Detailed Description of the Preferred Embodiment An embodiment of the present invention is explained with reference to Figs. 1 and 2.

A valve assembly 2 is fixed to a neck portion la of a gas cylinder 1. A valve casing 3 of the valve assembly 2 is provided with a leg threaded portion 3a projected downwardly and an outlet nozzle 3b horizontally swelled out of a halfway height portion of the valve casing 3. The leg threaded portion 3a is formed at its bottom surface with a gas inlet 4 and the outlet nozzle 3b is formed at an end surface thereof with a gas outlet 5.

The gas inlet 4 is communicated with an inner space (A) of the gas cylinder 1. A gas taking-out mouthpiece or a gas charging mouthpiece (either of them being not shown) is adapted to be connectable to the gas outlet 5.

While the gas cylinder 1 is being transported or stocked, a protector cap (not shown) is fixed to an outer peripheral portion of the neck portion la by a screw-thread engagement or the like and thus the protector cap covers the valve assembly 2.

A first valve 11 for closing is provided in a gas taking-out passage 6 extending from the gas inlet 4 to the gas outlet 5. The gas taking-out passage 6 is composed of an inlet passage 7 formed on a primary side of the first valve 11 and an outlet passage 8 formed on a secondary side of the same. A relief passage 9 branching off from the inlet passage 7 is provided at its terminal end with a safety valve 10 of burst plate type.

Further, the outlet passage 8 is provided at its midway portion with a second valve 12 for responding to pressure.

The first valve 11 is provided with a first valve seat 14 and a first valve chamber 15, which are arranged in series with each other, and with a first valve member 16 inserted into the first valve chamber 15 in such a manner as to be vertically movable. The first valve member 16 is opened or closed relative to the first valve seat 14 by a spindle 17 and a handle 18. These spindle 17 and handle 18 compose an opening and closing means (B).

Next the second valve 12 for responding to pressure is explained more concretely.

The outlet nozzle 3b having the outlet passage 8 arranged therein is swelled out of a peripheral wall of the first valve chamber 15 into the external space of the valve casing 3 and its axis is arranged in such a state that it does not intersect an axis of the first valve chamber 15.

The second valve 12 within the outlet nozzle 3b is provided with a second valve seat 20 and a second valve chamber 21, which are horizontally arranged in series with each other. More specifically, a female screw 23 for incorporation is formed at one of both ends of the outlet nozzle 3b, which end is opposite to the gas outlet 5.

The second valve chamber 21 is formed in a closure bolt 24 hermetically engaged with the female screw 23. A second valve member 25 is hermetically and movably inserted into the second valve chamber 21 through an O-ring (a sealing portion) 26 and brought into sealing contact with the second valve seat 20 through another O-ring (another sealing portion) 27. The second valve member 25 is urged toward the second valve seat 20 by a valve closing spring 28. A sealing diameter (D) of the second valve member 25 to the second valve chamber 21 is set at a value larger than a sealing diameter (d) of the second valve member 25 to the second valve seat 20.

A pressurizing chamber 30 for opening valve is annularly formed on an outer periphery of the second valve member 25 and between both of the O-rings 26 and 27. The pressurizing chamber 30 is communicated with the first valve chamber 15 via an intermediate passage 31. Further, a communication passage 33 is extended through the closure bolt 24 at the center portion thereof.

One end of the communication passage 33 is communicated with the second valve chamber 21 and the other end of the same is communicated with the external space of the valve casing 3.

The valve assembly 2 operates as follows.

When taking out a gas, a gas taking-out mouthpiece (not shown) is connected to the gas outlet 5 and in this state the first valve 11 is opened. Then a high pressure gas within the gas cylinder 1 is flowed into the pressurizing chamber 30 through the first valve chamber 15 of the first valve 11 and the intermediate passage 31. The pressure of the flowed-in gas makes a differential pressure corresponding to the difference of area between the sealing portions of the two o-rings 26 and 27 (a portion of the diameter (D) and another portion of the diameter (d)) act on the second valve member 25. The differential pressure spaces the second valve member 25 apart from the second valve seat 20 against the spring 28. Then the second valve member 25 is kept open by a pressure acting on the whole area of the portion of the diameter (D), whereby the gas is taken out of the gas outlet 5.

When charging a new high pressure gas into the evacuated gas cylinder 1, a gas charging mouthpiece (not shown) is connected to the gas outlet 5 and the gas is supplied from the gas charging mouthpiece to the outlet passage 8 with the first valve 11 kept open. Then the pressure of the supplied gas spaces the second valve member 25 apart from the second valve seat 20 against the spring 28, whereby the gas is charged from the gas outlet 5 into the inner space (A) of the gas cylinder 1 through a hole of the second valve seat 20, the pressurizing chamber 30, the intermediate passage 31, the first valve chamber 15, the inlet passage 7 and the gas inlet 4 in order.

Figs. 3 and 4 show a first and a second modifications, respectively. In these modifications the members of the same constructions as those of the embodiment are in principle referred to by the same numerals. On this condition these modifications are explained as follows.

In a first modification shown in Fig. 3, a filter 36 is provided in the communication passage 33. The filter 36 makes it possible to prevent the dust, salinity or like foreign matters existing in the external space of the valve casing 3 from invading into the second valve chamber 21.

The considered examples of the filter 36 are an air filter made of synthetic resin, a sintered metal and a screen.

In a second modification shown in Fig. 4, the communication passage 33 is composed of the following three passages 41, 42 and 43. More specifically, formed in the closure bolt 24 is a first passage 41 extending axially and then diametrically. And an annular second passage 42 is formed by a relief margin of the threads between a base portion of the bolt 24 and a right end portion (a front end portion) of the female screw 23. Further, formed at a right end portion of the outlet nozzle 3b is a diametrically extending third passage 43. This third passage 43 communicates the annular second passage 42 with the external space of the valve casing 3.

The communication passage 33 of the above construction becomes larger in entire length than that shown in Fig. 1 or Fig. 3, so that it is possible to effectively prevent the invasion of the foreign matters.

Although an axis of the first passage 41 is shown to coincide with an axis of the third passage 43, these axes are preferably arranged to deflect in a peripheral direction relatively to each other. More specifically, the relative peripheral deflection of these axes makes the passage 33 bend and at the same time become far larger in entire length, so that it is possible to more effectively prevent the invasion of the foreign matters.

Besides, the filter 36 shown in Fig. 3 may be attached to the communication passage 33 shown in Fig. 4.

The embodiment and the modifications can be further modified as follows.

It is also possible to provide the closure bolt 24 with the second valve seat 20 and the pressurizing chamber 30 in addition to the second valve chamber 21.

It is sufficient if the communication passage 33 is provided in the peripheral wall of the second valve chamber 21. As a matter of course, the passage 33 is not limited in any way to the construction of the embodiment or those of the modifications.

The opening and closing means (B) may be provided with an actuator such as an air cylinder, an electric motor or the like instead of having the handle 18 to be operated manually.

The first valve 11 may be of metal diaphragm type or ball valve type instead of seat valve type.

Claims

1. A valve assembly for gas cylinder comprising a valve casing (3) within which an inlet passage (7), a first valve (11) for closing and an outlet passage (8) are provided in order between a gas inlet (4) and a gas outlet (5), a second valve (12) for responding to pressure being disposed at a halfway portion of the outlet passage (8), characterized in that: an outlet nozzle (3b) having the outlet passage (8) arranged therein is swelled out of a peripheral wall of a first valve chamber (15) of the first valve (11) into the external space of the valve casing (3) in such a state that its axis does not substantially intersect an axis of the first valve chamber (15); and that the second valve (12) is provided in the swelled out outlet nozzle (3b), a pressurizing chamber (30) for opening valve, which is communicated with the first valve chamber (15), being arranged on an outer periphery of a second valve member (25) to be hermetically inserted into a second valve chamber (21) of the second valve (12) and urged toward a second valve seat (20) by a valve closing spring (28), a communication passage (33) for communicating the second valve chamber (21) with-the external space of the valve casing (3) being provided in a peripheral wall of the second valve chamber (21).

2. A valve assembly for gas cylinder as set forth in claim 1, wherein a closure bolt (24) is engaged with a female screw (23) for incorporation provided at one of both ends of the outlet nozzle (3b), which end is opposite to the gas outlet (5), the second valve chamber (21) being formed in the closure bolt (24), the communication passage (33) being composed of a first passage (41) formed in the closure bolt (24) and extending diametrically, an annular second passage (42) formed between a base portion of the closure bolt (24) and a front end portion of the female screw (23), and a diametrically extending third passage (4-3) formed in the outlet nozzle (3b) so as to communicate the annular second passage (42) with the external space of the valve casing (3).

3. An valve assembly for gas cylinder as set forth in claim 2, wherein an axis of the first passage (41) and an axis of the third passage (43) are arranged to deflect in a peripheral direction relatively to each other.

4. A valve assembly for gas cylinder as set forth in any of claims 1 to 3, wherein a filter (36) is provided in the communication passage (33).