Regulated Gas Flow Control Valve

This invention relates to flow control devices and, more particularly, to a compact, regulated gas flow control valve.

The invention is particularly concerned with controlling the flow of oxygen from oxygen cylinders wherein oxygen is stored at extremely high pressures such as 500-2000 p.s.i.g., there being a requirement to deliver oxygen from such source at a desired, constant flow rate as dictated by medical requirements, such as for emergency treatment, and for hospital, clinical and other usages. Accordingly, it may be required to deliver oxygen at a flow rate which may vary from very little, such as as low as 0.25 liters per minute, up to approximately 15 liters per minute. It is, therefore, desired to provide not only the function of reducing the high pressure to a regulated substantially constant delivery pressure, but also to allow ready preselection of a desired flow rate.

Medical professionals in institutions or other users of such equipment may have different preferences as to the minimum and maximum volumetric flow rates which such apparatus should provide. Further, different users are expected to have different preferences as to the available sequence of flow rates.

For example, one user may prefer a control sequence of 0.5, 0.75, 1, 1.5, 2, 3.5, etc., liters per minute; whereas another user may prefer a sequence of 1, 2, 4, 6, 8, etc., liters per minute, so that the design of such apparatus is rendered difficult for all intended modes of usage. Although the use of vernier controls allowing infinite adjustments of flow rates has been proposed, in medical usage it is preferred to be able to positively and rapidly allow selection only according to such a preferred sequence, thereby assuring rapid, error reducing selection, as required in prompt emergency treatment and with only definite, defined control positions being available thereby to preclude inaccurate settings, inoperative positions, and to obviate close visual monitoring of selections and flow rates.

It is an object of the present invention to provide a compact, regulated gas flow control valve of improved, advantageous function and design.

It is a further object of the invention to provide such an improved flow control valve which is particularly intended for controlling the flow control of oxygen delivered from a high pressure oxygen cylinder.

It is a further object of the invention to provide such a gas flow control valve which accurately and reliably drops such high pressure to a substantially constant, regulated delivery pressure and which allows selection of a precalibrated flow rate of oxygen from said constant delivery pressure only according to a preferred schedule of delivery rates.

Additionally, it is an object of the invention to provide such a gas flow control valve which allows definite, positive selection only of a desired one of a plurality of available flow rates, precluding inaccurate or indefinite settings, inoperative selector positions, and eliminating need for close visual monitoring of the control valve or flow rates provided thereby.

Among other objects of the present invention are the provision of a gas flow control valve which is of extremely compact, streamlined and efficient construction, being both reliable and long lasting in usage as well as relatively light in weight; which is rapidly and conveniently securable to a conventional high-pressure oxygen cylinder; which provides facility for rapid emergency connection to receive oxygen directly at a substantially constant delivery pressure without flow control; and which allows for automatic pressure relief operation.

Briefly, a regulated gas flow control valve of the invention includes a single valve body having clamp means at one end for clampingly securing the valve body directly to a source of high pressure gas, such as an oxygen cylinder, there being an inlet for this purpose at one end of the valve body for directly receiving the high pressure gas for such source and admitting the gas to the interior of the valve body. The clamp arrangement causes the body to be tightly maintained in communication with the gas source. Within the valve body, which is of compact configuration, there is a regulator for dropping the high pressure to a low pressure and for maintaining the low pressure substantially constant. The regulator includes a valve seat to which said inlet permits communication of said gas at high pressure. A valve member including a seal is positioned within the valve body for axial movement between closing and opening positions. In the open position, the seal is unseated from the seat to open the inlet and to admit gas at high pressure into an inlet chamber surrounding the valve seat. In the closed condition, the valve member causes the seal to be positioned against said seat to block the inlet and to limit or prevent gas from being admitted to the inlet chamber. As the gas enters the inlet chamber upon opening movement of the valve body, the gas is permitted to expand into the inlet chamber. A piston, also within the valve body, is axially movable therein, being connected to the valve member for corresponding movement thereof in response to piston movement. A compression spring within the valve body resiliently biases the piston in a direction for opening movement of the valve body. A piston chamber is defined, also within the valve body, over the piston head, there being a gas conduit providing communication between the inlet chamber and the piston chamber for admitting low pressure gas to the piston chamber for exerting pressure upon the piston head, and causing the piston to move to a position urging the seal of the valve member against the valve seat to an extent causing pressure within the piston chamber to be maintained at a substantially constant delivery pressure. A rotor is positioned proximate the piston chamber, and is fitted with a plurality of precalibrated orifice means, each configured for receiving the gas at said constant delivery pressure. A selector at one end of the valve body opposite from the inlet is provided for rotating the rotor relative to a gas outlet port for delivery of the gas, such as oxygen, at a precalibrated flow rate determined uniquely by respectively one of the orifice means. A positive detent mechanism assures that the only positions of the rotor may be for completely preventing flow of the gas or permitting flow only through one of the orifice means.

Other objects and features will be in part apparent and in part pointed out hereinbelow.

FIG. 1 is a side elevation view of a regulated gas flow control valve in accordance with and embodying the present invention.

FIG. 2 is a longitudinal cross sectional view as taken generally along line 2--2 of FIG. 1.

FIG. 3 is a lateral cross section as taken along line 3--3 of FIG. 1.

FIG. 4 is a lateral cross section, as taken along line 4--4 of FIG. 2.

FIG. 5 is a lateral cross section of the valve as taken generally along line 5--5 of FIG. 2.

FIG. 6 is similarly a lateral cross section of the valve as taken generally along line 6--6 of FIG. 2.

FIG. 7 is a fragmentary view, partly in cross section, illustrating certain gas flow distribution structure within the valve.

FIG. 8 is a fragmentary lateral cross section as taken generally along line 8--8 of FIG. 7.

FIG. 9 is a lateral cross section illustrating certain features of the gas flow distribution structure.

FIG. 10 is a left end elevation view of the new valve.

FIG. 11 is a lateral cross section illustrating features of a certain selector of the valve, as taken generally along line 11--11 of FIG. 2.

FIG. 12 is a partial longitudinal cross sectional view illustrating movement of a certain piston and valve member within the valve.

FIG. 13 is an enlarged fragmentary view of a portion of FIG. 5, illustrating a certain precalibrated orifice means of the invention and its securement.

FIG. 14 is a lateral cross sectional view like FIG. 11 but illustrating a different orientation of the selector for limiting its movement between selected arcuate limits.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now by reference numerals to the drawings, indicated generally at 10 in its entirety is a compact, regulated gas flow control valve of the invention. Valve 10 is especially designed and intended for ready attachment to an oxygen cylinder (not shown) or other high pressure source of gas. The new valve may be used for providing a predetermined sequence of flow rates at a substantially constant delivery pressure such as about 5-50 p.s.i.g. even though the source pressure may be, for example, 500-2000 p.s.i.g.

Although especially suited for delivery of oxygen for emergency, clinical and hospital use, as in ambulances, emergency rooms and in other medical facilities, the new control valve is useful also for controlling the dispersing of other gases such as specialty gases within the medical, scientific and commercial fields.

Valve 10 includes a single body 12 of cylindrical form, being entirely compact and small in dimensions, as of diameter of about 3.5 cm. formed, for example, of aluminum alloy, stainless steel or brass. For facile, rapid attachment of valve 10 to an oxygen or similar high pressure cylinder, body 12 is provided at what may be termed its lower, or inner, end with a bracket or yoke 14 of generally U-shaped configuration including upstanding leg portions 16, 16' and a relatively thicker end portion 18 which is bored and tapped at 20 to receive a clamp screw 22 having a T-shaped handle 24. Screws 25, 25' affix the yoke legs to valve body 12.

At 26 is designated an inlet having an inlet port or bore 26a dimensioned for being maintained, upon tightening of screw 22, in tight communication with the conventional outlet of the gas cylinder to which valve 10 is secured, thereby admitting gas at high pressure, such as up to about 2000 p.s.i.g. to port 26a.

A pair of pins 27, 27' are spaced relative to inlet 26 for being received by corresponding recesses conventionally available upon the gas cylinder, thereby to precisely fix valve 10 against rotation relative to the cylinder and with inlet 26 in proper alignment.

A mesh filter 28 is fitted within bore 26a being maintained by tight fitment against the shoulder formed by a smaller diameter passage 30, which in turn connects to a smaller diameter passage 32. Passage 32 opens into an inlet chamber 34 through an annular valve seat 35 which protrudes into the chamber 34 a small distance for definitive engagement by a valve seal 36.

Seal 36 is carried at the lower end of a valve member 38 of cylindrical form carried by a piston 40 axially slidable within a cylindrical bore 42. A reduced diameter stem 44 of the valve member is, for this purpose, fitted closely into a central bore of piston 40. Valve member 38 is shown in valve-opening position with seal 36 fully lifted from seat 35, being the position occupied when gas is not supplied at high pressure through inlet 26. However, piston 40 and valve member 38 are axially movable to a closing position, explained below, in response to gas supplied through passage 26a.

Fitted within an annular groove around piston 40 is an O-ring 46 whereby pressure may be developed and maintained within a piston chamber or headspace 48 over the head 50 of the piston, even though the piston may move in response to such pressure (as in FIG. 12) within bore 42. Opening through the wall of the valve body into said bore is a passage 52 whereby the valve body interior 54 defined by said bore 42 is at atmospheric pressure.

Valve member 38 is drilled to provide a cruciformconfigured passage 56 opening laterally at opposite sides into an annular groove 58 whereby there is communication at all times between inlet chamber 34 and the cruciform passage 56. The latter connects to a larger diameter passage 60 which opens into the headspace 48, thereby permitting pressure to be developed within such headspace whenever gas is admitted to inlet chamber 34 by opening movement of valve member 38. Valve member 38 spacedly from cruciform passage 56 is provided with a curcumcential outwardly opening recess c accepting a gasket or O-ring r for a sealing relationship between valve member 38 and guide 62 whereby inadvertent escape of gas into valve body interior 54 for ultimate loss thru passage 52 is inhibited.

Surrounding and guidingly receiving valve member 34 is a flanged annular guide 62 having a central portion 64 and a hex-shaped flange portion 66, the latter being centrally recessed to define, together with the lower end wall 68 of bore 42, said inelt chamber 34. An annular groove upon the lower face of flange portion 66 carries an O-ring or V-edged seal ring 70 for providing gas-tight sealing against end wall 68 when urged thereagainst. For that purpose, a coiled compression spring 72 bears against a washer 74 seated upon the flange portion 66 and, at its opposite end, against piston 40, being received within an annular groove 76 of the piston.

Normally, spring 72 maintains guide 62 in the position shown, preventing gas under pressure within inlet chamber 34 from entering space 54 and being thereby vented to atmosphere through port 52. But if, upon high pressure intially developing within inlet 26a, as upon connection to the gas cylinder or turning on of the latter's valve, or other transient conditions, excess pressure intially should develop within chamber 34, the high pressure may cause momentary movement of guide 62 toward piston 40. This will relieve any high pressure in chamber 34 until normal valve-closing operation of piston 40, as explained below, can occur to close seal 36 upon seat 35.

Referring to FIG. 4, located below the pressure regulator just described is a threaded opening 78 which communicates with a port 80 opening into end wall 68 at a point located within inlet chamber 34. Opening 78 may be provided with a removable plug or else a capped or valved emergency fitting (not shown) whereby reduced pressure gas, e.g., oxygen, can be directly obtained from chamber 34 for the purpose of attaching additional medical devices requiring a higher flow rate.

Also depicted is a threaded opening 82 for receiving a conventional pressure gauge (not shown). Opening 82 communicates with passage 30 whereby such gauge will be caused to display the pressure in the gas cylinder. If such gauge is not employed, a plug is threaded into opening 82.

Valve 10 also includes flow control valve means including a control knob 84 at the upper end of the valve for allowing an operator to select a predetermined rate of gas flow from an available schedule of flow rates, or to select no gas flow.

For this purpose, there is provided a disc-shaped rotor 86 carried by a shaft 88 connected to knob 84 and extending coaxially through a cylindrical extension 90 of valve body 12, to which the extension is secured as by a ring 92 which in threaded engagement with body 12 for convenient removal of extension 90, and with knob 84 and rotor 86 secured and intact to permit changing of rotor 86 for purposes presently appearing or for inspection, etc.

Rotor 86 is removably secured to shaft 88 by a screw 94 seated upon a flat washer 96a and a Belleville-type spring washer 96b. The latter provides a tightly clamped, yieldable relationship between rotor 86 and shaft 88. An O-ring 98 provides gas-tight sealing of shaft 88 within body extension 90.

The lower face of rotor 86 is oriented toward piston face 50 without intervening structure and with there being only said head space 48 therebetween. Carried by the rotor are a plurality of flow control orifice means or inserts 100a-g each uniquely determining or defining a precalibrated gas flow rate to be provided by valve 10 through an outlet fitting 102 (FIGS. 7 and 9). Also carried by the rotor is an insert 100h which is closed, or may have a blank space, to provide for zero gas flow.

Referring to FIG. 7, fitting 102 is threaded into body extension 90 and communicates to the upper side of rotor 86 through a passage 104 opening into the ceiling of a recess 106 in which rotor 86 is located, and in alignment with each of the orifice fittings. Further, rotor 86 is provided with eight apertures 108 of fixed size which open from the upper face of the rotor into respective cavities, as at 110 for receiving the orifice fittings.

Referring to FIG. 2, each such orifice fitting, as that shown at 100d, is provided with an orifice of unique, precise size including a flanged portion and a smaller diameter stem portion, and sealed within its cavity by a gasket 112. The body of the rotor may be of synthetic material, e.g., polysulfone, while each orifice fitting is of brass, etc.

It is specifically preferred to provide each orifice fitting with a characteristic finish, colored, e.g., blue, yellow, gray, etc., according to the flow rate it will provide. Since each such insert is exposed to a substantially constant delivery pressure, e.g., 50 p.s.i.g. present within head space 48, its flow rate will be dependent upon the orifice dimensions.

It is preferred to precalibrate each such insert 100a-100f according to the precise flow rate it demonstrates in testing apparatus prior to assembly of the valve, and at a given source pressure. Accordingly, the precalibrated flow rate can be correlated with the color of each insert, and assembly is facilitated by the assurance that placement of the inserts sequentially within their rotor cavities according to a desired color scheme will provide a preselected sequence of precise flow rates, such as 0.5, 1.0, 1.5, 2.0, 3.0, 4.0 and 5.0 liters per minute. The blank insert 100g provides zero flow rate.

The gasket 112 in each cavity assures that gas flow will occur only through the given orifice dimensions. Referring to FIG. 13, each insert 100a, etc., is maintained tightly within its recess 110, clamped against the respective gasket, by staking at three points 114 in the rotor surface surrounding the insert.

In order to assure of gas tight relationship against the upper face of the rotor, the opposed ceiling 116 (FIG. 9) of cavity 106 is provided with three shallow cylindrical recesses 118 receiving respective O-rings 120 for bearing against the upper rotor face 122 in equispaced, even relationship, and with passage 104 opening through one only of recesses 188 (FIG. 9). The spring washer 96b resiliently urges face 122 tightly against such O-rings 120, whereby only gas through a predetermined one of orifice fittings 100a-f will be delivered to fitting 102.

Referring to FIG. 8, a portion 124 of shaft 88 is octagonal to provide a cam surface 126 against which a pawl 128 is urged by a spring 130 secured by a screw 132, thereby providing a positive detent mechanism for shaft 88, knob 84 and rotor 86 as a unit. Provided also is a keyway 128 (FIG. 6) within rotor 86 for receiving a keyed portion 130 (FIG. 9) of the shaft for assuring of a fixed relationship between the rotor and the shaft, as will facilitate location of inserts 100a-g in their proper sequence, and to prevent slippage of the rotor upon the shaft. Knob 84 similarly may be secured to as by a set screw to a keyed or flatted portion 132 (FIG. 7) of the shaft.

It is preferred to provide in knob 84 a relatively deep notch 134 (FIG. 10) for permitting observation of an index plate 136 carrying indicia, such as "1" shown, indicating a selected flow rate, e.g., 1.0 liter per minute, the same being clearly visible through the notch from above knob 84. Additionally, indicia are located, as at 138 generally, around the side surface of body extension 90.

Limitation of rotation of knob 86 between desired arcuate limits is provided, according to one preferred arrangement, as shown in FIG. 11, which may be compared with FIG. 7. A pin 140 extends upwardly from body extension 90 for being received within an arcuate recess 142 in the lower face of the knob.

Referring to FIG. 14, another arrangement for limiting rotation of a modified knob 86' is provided. Around a flange or lip 144 of the knob are spaced notches 146 aligned radially with corresponding notches 148 within an inner flange or hub 150. Shown bridging two pairs of these inner and outer notches are removable bars 152a, 152b, and with stop projection 140 engaging bar 152a to limit further counterclockwise rotation (as viwed from the rear) of knob. Similar, bar 152b will limit clockwise rotation. The bars may be removed entirely or placed as desired to limit rotation of the knob to movement between preselected position. Thus, for example, oxygen flow may be limited to flow of from 1.0 to 2.0 liters per minute by simply locating bars 152a, 152b to preclude selection of other flow values. This allows medical personnel to configure valve 10 so that a patient may not select an oxygen flow level which would be harmful.

In operation of the new valve, it is clamped to an oxygen cylinder, for example, admitting high pressure gas into chamber 34 through valve seat 35. Any transient overpressure is vented to atmosphere momentarily by relief valve movement of sleeve 64, as explained above.

The pressure developing in chamber 34 is communicated through passage 56 to headspace 48, exerting force on piston 40 for closing movement of valve member or piston rod 38. The seal 36 is, accordingly, urged toward seat 35 to limit further entry of gas into chamber.

During flow of gas through the valve and from outlet 102, as for medical usage, for example, piston 40 will be driven by pressure in headspace or chamber 48 to a position, opposed by spring 72, to maintain the pressure in chamber 48 at a substantially constant delivery value, such as about 50 p.s.i.g. Such valve may be changed by changing spring 72 to one having a different spring constant. If pressure drops in chamber 48 below the delivery value, spring 72 will urge the piston upwardly for increasing the volume of gas entering chamber 34. Or, if pressure in chamber 48 rises above the delivery value, the piston will be driven to a position closing or restricting valve seat 35 for limiting flow of gas into chamber 34. To the extent valve member opens from seat 35, gas expands into chamber 34 with drop in pressure.

Such gas at substantially constant, thus regulated delivery pressure is made available to each of the orifice inserts 100a but may flow only through such one of inserts 100a-g as is aligned with passage 104 by positioning of selector knob 84. Positive positioning of the knob is assured by the detent mechanism shown in FIG. 8.

The new valve is seen not only to be compact and of relatively streamlined, modern design but also to be reliable, tamper-resistant, fail-safe and highly advantageous to utilize in a rapid, facile manner, providing numerous advantages of construction and operation. Accordingly, the objects of the invention and other advantageous results are believed.

Although the foregoing includes a description of the best mode contemplated for carrying out the invention, various modifications are contemplated.

As various modifications could be made in the constructions herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing descriptionor shown in the accompanying drawings shall be interpreted as illustrative rather than limiting.