HAND-HELD, LOW-FLOW THERAPEUTIC GAS DISPENSERS

Abstract

A hand-held, low-flow dispenser comprises an enclosure holding a gas cartridge. A spring-biased needle is advanced to puncture a septum on the gas cartridge, and a separate spring-biased ball valve is used to turn the resulting gas flow off and on as well as to control the flow rate.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

1. Field of the Invention

The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to methods and hand-held apparatus for delivering therapeutic gases at a low-flow rate suitable for patient administration.

Gas delivery systems for inhalation therapies are well-known. Drugs, mists, vapors, and the like, can and be delivered from a wide variety of hand-held and other apparatus. For example, heated liquids have been used to provide vapors for delivering a wide variety of drugs and therapies. Hand-held devices have also been developed for both oral and nasal inhalation delivery. For example, powders may be delivered using disc inhalers where the patient inspires powder medicine from a receptacle on a disc. Metered-dose inhalers (MDI's) rely on a pressurized propellant in a cartridge for delivering pressurized doses of a drug to a patient. Most if not all of these drug delivery devices are intended to provide a relatively high gas flow rate compatible with a patient's inhalation rate.

Recently, a new therapy relying on the non-inhalation administration of therapeutic gases at relatively low-flow rates on the order of 0.5 cc/sec to 20 cc/sec has been proposed. As described in U.S. Pat. No. 7,017,573, carbon dioxide and a variety of other therapeutic gases are suffused through a patient's nasal and/or oral cavities without inhalation. Typically, the gases are introduced from a dispenser to a patient's nostril and allowed to flow through the nasal cavity while exiting through the other nostril or the mouth. The gases, such as substantially pure carbon dioxide, can be irritating to the throat and lungs if inhaled, and flow rates higher than 10 cc/sec to 20 cc/sec can be uncomfortable to the patient.

U.S. Pat. No. 7,017,573 describes a hand-held dispenser suitable for delivering such low-flow rates, where the particular flow rate is patient adjustable. The device relies penetrating a needle through a septum on a cartridge of the carbon dioxide or other therapeutic gas. The flow rate is controlled by rotating a cap which holds the needle, where such rotation axially translates the needle in and out the hole which was originally formed. The flow rate is thus controlled by the annular opening between the needle and the hole in the septum where the area of the annular varies depending on the axial position of the needle.

While this is a workable system, the dimensions of the needle and other system components must be carefully controlled in order to assure both the ability to stop flow entirely as well as the ability to carefully adjust the flow rate between the desired minimum and maximum ranges. The need to provide such close tolerances on system components complicates the manufacturing and raises the price of the hand-held dispenser considerably.

For these reasons, it would be desirable to provide improved hand-held, low-flow therapeutic gas dispensers which are both reliable and relatively simple to operate. Such hand-held dispensers should allow for relatively low manufacturing costs, be convenient for held-held patient use, provide stable, low-flow rates on the order of a fraction of a cc/sec while being adjustable to higher flow rates from 5 cc/sec to 20 cc/sec or even higher. At least some of these objectives will be met by the inventions described hereinbelow.

2. Description of the Background Art

A list of relevant U.S. Patent documents and foreign patent documents is provide below. U.S. Pat. No. 7,017,573 has been discussed above.

	Number	Date
U.S. PATENT DOCUMENTS
			Inventor
	7,017,573	April 2006	Rasor et al.
	6,001,332	December 1999	Garrett
	5,993,428	November 1999	Hardge
	5,983,891	November 1999	Fukunaga
	5,941,241	August 1999	Weinstein et al.
	5,938,590	August 1999	Elliott
	5,908,870	June 1999	McLeod
	5,839,433	November 1998	Higenbottam
	5,807,357	September 1998	Kang
	5,570,683	November 1996	Zapol
	5,562,644	October 1996	McLeod
	5,485,827	January 1996	Zapol
	5,431,155	July 1995	Marelli
	5,262,180	November 1993	Orlando et al.
	4,934,359	June 1990	Blaine
	4,554,916	November 1985	Watt
	4,465,067	August 1984	Koch et al.
	4,273,124	June 1981	Zimmerman
	4,188,946	February 1980	Watson et al.
	4,137,914	February 1979	Wetterlin
	4,067,499	January 1978	Cohen
	3,974,830	August 1976	LaVerne
	3,934,585	January 1976	Maurice
	3,870,072	Ma 1975	Lindmann
	3,776,227	December 1973	Pitesky et al.
	3,513,843	May 1970	Exler
	3,127,058	March 1964	Johnston
	2,920,623	January 1960	Holt
	2,860,634	November 1958	Duncan et al.
	2,651,303	September 1953	Johnson et al.
	1,449,047	March 1923	Johnson
	1,288,850	December 1918	Easly
FOREIGN PATENT DOCUMENTS
			Country
	247 873	March 1947	CH
	837 158	April 1952	DE
	14 91 660	August 1969	DE
	89 06 590	October 1989	DE
	4319612	December 1994	DE
	19548652	October 1997	DE
	0 768 094	April 1997	EP
	2656218	December 1989	FR
	408 856	April 1934	GB
	WO 91 08793	June 1991	WO/PCT
	WO 93 00951	January 1993	WO/PCT
	WO 99/29249	June 1999	WO/PCT
	WO 00/51672	September 2000	WO/PCT
	WO 00/57851	October 2000	WO/PCT

BRIEF SUMMARY OF THE INVENTION

The present invention provides improved hand-held, low-flow therapeutic gas dispensers which are both economical to manufacture and easy to use by the patient. The dispenser utilizes a high pressure gas cartridge, and separate mechanisms are used for opening the gas cartridge and for controlling the flow rate of gas to the patient. The opening mechanism penetrates a septum on the gas cartridge to form an opening having a sufficient clearance with the penetrating mechanism so that flow through the penetration will not limit the rate of flow to the patient. The separate flow control mechanism allows the user to repeatably and stably adjust flow at very low-flow rates, typically from rates of from 0.5 cc/sec or lower to rates of from 5 cc/sec, 10 cc/sec, 15 cc/sec, 20 cc/sec, or higher. Moreover, the flow control mechanism will allow the user to provide a complete shut-off of the gas flow with minimum risk of leakage and maintenance of high gas pressure over extended time periods. In the exemplary embodiments, the flow control valve will typically be calibrated to deliver gas in the range from 1 cc/sec to 50 cc/sec

In a first aspect of the present invention, a hand-held, low-flow gas dispenser comprises an enclosure having a gas outlet. The enclosure is adapted to receive a pressurized gas cartridge having a penetrable septum. A pin having a tip for penetrating the septum is carried in a pin carrier having an “advanced” configuration for penetrating the pin through septum to form a hole or other opening (including round and other shapes) in the septum and a “retracted” configuration for withdrawing the pin from the hole to allow gas flow from the cartridge.

As the pin is intended to open the gas cylinder but not to control flow therethrough, it is advantageous that the pin be prevented from reentering the hole that is created after it is retracted. This can be accomplished, for example, by mounting the pin on a “bistable” mechanism which carries the pin in both an advanced configuration or position and a retracted configuration or position. By mounting the bistable carrier so that it automatically switches from the advanced configuration to the retracted configuration after the pin has penetrated the septum, the pin can be withdrawn from the hole and maintained in the retracted configuration. As illustrated in the specific embodiments below, the bistable carrier will typically comprise a spring having both an advanced and retracted stable configuration where the pin or spring engages a stop or other mechanism to push the spring from the advanced to the retracted configuration as the pin carrier is advanced. A variety of other mechanical elements or components could also be provided to effect such advancement and retraction of the pin.

A flow control system is placed in series with pin and pin carrier to receive and adjust the flow rate of therapeutic gas released from the penetration in the septum of the gas cartridge. The flow control system, however, will form a separate component or assembly and will be separately adjustable from the pin and pin carrier used to penetrate the septum of the cartridge. The flow control system will typically include at least one flow control valve which acts as a hybrid valve/regulator, as described in greater detail below in connection with the specific embodiments.

Usually, the pressured gas cartridge will form a non-removable component of the hand-held gas dispenser. In other embodiments, however, the gas cartridge may be removably received within the enclosure to allow removal and replacement of the gas cartridge after gas has been depleted.

The pin in the septum-penetrating structure will usually have a solid core, allowing very small pin widths to be utilized, typically in the range from 0.5 mm to 2 mm, with a tip radius less than 0.1 mm. The use of such narrow width pins is advantageous since it reduces the force necessary to penetrate the septum. The pins will typically have circular cross-sections, but could have a variety of non-circular cross-sections, such as having a narrow, triangular tip. Additionally, although solid core needles are preferred, hollow core needles could be used although they are generally less preferable. Prior art designs have often used hollow needles in order to both penetrate the septum and provide a flow path for pressurized gas leaving the cartridge. The need to provide a hollow passage within the penetrating needle requires use of a larger needle which can increase the necessary needle penetration force and render manufacturer and use of the dispenser more difficult.

In the exemplary embodiments, the septum-penetrating pin is carried on a spring-loaded carrier, such as a spring disc, having a concave or other retracted configuration and a convex or other advanced configuration. As the carrier and pin are advanced forwardly to penetrate the septum, they will engage a stop or other structure surrounding the septum which will push the carrier back to the retracted (concave) configuration after the septum has been fully penetrated. In the concave configuration, the spring is abruptly withdrawn from the hole or other opening that it just created, thus creating a flow path around the pin from the cartridge and through the septum. This flow path will be relatively unobstructed as the pin has been withdrawn to provide a large clearance area. The septum will remain open (with the pin retracted) throughout the use of the gas dispenser until the cartridge is depleted. Turning the flow of gas on and off as well as regulating the flow rate will be accomplished using the flow control system which is a separate component of the gas dispenser.

In the exemplary embodiments, the flow control system will comprise a spring-loaded valve with an axial valve stem for pushing a ball or other closure element against the spring force. In its unloaded configuration, the valve element closes against a valve seat under the spring force and pressurized gas. When the valve element is pushed by the stem, an opening will be formed between the valve seat and the ball valve to permit a controlled flow of gas, where the flow rate is typically in the ranges described above. As a particular advantage of the present invention, the gas pressure and spring force both tend to close the ball valve against the valve seat, thus providing a fail-safe mechanism for shutting off the gas flow when it is desired to stop using the dispenser. The valve seat may be rigid or compliant. Rigid valve seats may be preferable as they provide more repeatable flow performance in response to temperature and other environmental changes.

In addition to controlling flow rate, the flow control system will also provide for a pressure reduction where the small aspect ratio between the ball or other closure element and the size of the piston (described in more detail below) contribute greatly to the pressure reduction characteristics.

In the exemplary embodiments, the flow control valve is located in the enclosure between the gas cartridge and the outlet, typically having the septum-opening pin therebetween. In alternate embodiments, the flow control valve may be located in the neck of the gas cartridge. Having the control valve located in the gas cartridge would be particularly advantageous in embodiments where the gas cartridge is replaceable so that a fresh flow control element is provided each time the cartridge is replaced.

The hand-held, low-flow gas dispenser of the present invention is particularly useful for delivering carbon dioxide and other therapeutic gases to a patient's nasal and/or oral cavities, typically in the absence of inhalation, as described in U.S. Pat. No. 7,071,573, the full disclosure of which has been previously incorporated herein by reference. For such use, the gas outlet of the enclosure is typically adapted to seal against a nostril of the patient.

In a second aspect of the present invention, methods for dispensing a low-flow rate gas from a hand-held dispenser comprise pushing a spring-loaded pin through a septum on a gas cartridge in the dispenser to create a hole or other opening. The pin is allowed to spring back or otherwise retract from the opening to permit gas flow through a clearance surrounding the pin in the hole to an outlet on the dispenser, and a separate valve assembly is adjusted on the dispenser to control the flow rate of the gas. Typically, the gas will be a therapeutic gas, more typically being carbon dioxide. Carbon dioxide therapeutic gases will usually comprise at least 50% carbon dioxide by volume, often being substantially pure carbon dioxide. The valve will be adjusted to control flow at a desired rate, typically from 1 cc/sec to 50 cc/sec, more typically from 0.5 cc/sec to 20 cc/sec Adjusting the flow usually comprises turning a nose piece or other dial on the enclosure which adjusts the position of a spring-loaded ball valve, where the ball valve is usually located between the gas cartridge and the outlet within the enclosure. Although the flow control valve is typically adjusted using a nose piece on the hand-held dispenser, it will be appreciated that other control interfaces, such as sliding actuators, pushing actuators, other rotating actuators, and the like, could be provided for adjusting the flow rate.

In a third aspect of the present invention, a low-flow rate gas dispenser is manufactured by providing an enclosure having an outlet, a septum-penetrating pin, and a control valve stem. A gas cartridge is provided having a penetrable septum and a spring-loaded valve. The gas cartridge and the enclosure are assembled so that the pin is located adjacent the septum, and the control valve can engage the spring-loaded valve after the septum has been penetrated. Optionally, the assembly may be performed by a user who is replacing a spent cartridge with a new cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a hand-held, low-flow gas dispenser constructed in accordance with the principles of the present invention.

FIG. 2 illustrates a lower assembly of the gas dispenser with an upper cover removed.

FIG. 3 illustrates the lower assembly of FIG. 2 with an upper assembly removed.

FIG. 4 is an exploded view of the system components of the upper and lower assemblies of FIGS. 2 and 3.

FIG. 5 is an exploded view, in cross-section, of the upper assembly.

FIG. 6 is cross-sectional view of the lower assembly.

FIGS. 7A-7C illustrate the steps of puncturing a septum of a gas cartridge and thereafter controlling flow rate using a ball valve assembly.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIGS. 1-3, a hand-held, low-flow gas dispenser 10 constructed in accordance with the principles of the present invention comprises a lower assembly 14 and a cover 12. Removing the cover 12 reveals an upper assembly 16 (FIG. 2) including a nose piece 18 having a fitted end 20 which releases the therapeutic gas. Typically, the fitted end 20 is adapted to conform to a patient's nostrils for nasal infusion. It will be appreciated, however, that the shape could be modified for oral infusion or for conformance to other body orifices where delivery of a therapeutic gas might be desired.

Referring now to FIGS. 4 and 6, the lower assembly 14 comprises a housing or shell 22 which receives a gas cartridge 24 having a penetrable septum 26 at its upper end. The cartridge 24 has a threaded neck 28 and is held within the shell 22 by a cylinder nut 30 which seals to an upper lip 32 of the enclosure, as best seen in FIG. 6. Although shown with a threaded engagement, the cylinder could also have a non-threaded neck which is held by other mechanisms within the dispenser. A cylinder gasket 34 seals the septum to a passage 36 in a threaded neck 38 of the cylinder nut 30. Thus, it will be appreciated that if the septum 26 in the cylinder 24 is penetrated, gas will be able to flow upwardly through the passage 36. The gasket 34 provides a first mode of over pressure relief. When the flow control valve is closed, the gasket 34 will be exposed to pressure from the gas cylinder after the gas cylinder has been opened. If the pressure in the gas cylinder exceeds the expected value for any reason, such as exposure to heat, the material or other characteristic gasket 34 may be selected so that it will extrude in response to the pressure in order to permit release of the excess pressure through the side of the hand-held enclosure.

Referring now to FIGS. 4 and 5, the upper assembly 16 comprises a regulator body 40, the nose piece 18, a nose piece nut 42, and a needle 44 carried in a carrier formed as a disc spring 46. The regulator body 40 carries a valve seat insert 48 (the seat could alternatively be formed integrally with the regulator body 48) sealed by an O-ring 47, as best seen in FIG. 5, which comprises a ball 50 biased upwardly by spring 52 held in place by a filter 54 at its lower end. The spring 52 biases the ball upwardly against a cylindrical seat 56 formed at the lower end of a passage 58. As will be described in more detail below, a valve stem 60 is used to axially depress the ball 50 in order to open an annular or other passage between the ball and the seat 56. Gas flowing up through the passage 36 from cartridge 24 will pass through the filter 54, past the ball 50, through the passage 58, and into the nose piece 18. Thus, the gas will ultimately pass out through the port in fitted end 20. A second mode of over-pressure relief is provided by forming the regulator body 40 to include a “failure weld” in a wall thereof. The failure weld will be a slightly weakened portion which will fail in response to over-pressure from the gas cylinder when the regulator valve assembly is closed.

The nose piece 18 carries a regulator piston 62 having the valve stem 60 depending from its lower end. The regulator piston 62 is adapted to travel up and down in a receptacle 64 formed in the upper end of the regulator body 40. The regulator piston 62 has wings, bosses, or other features which travel in slots 68 surrounding the receptacle 64. The regulator piston 62 is biased downwardly by a spring 70 and seals against the inside of the receptacle 64 with 0-ring 66. A lower cam 72 rides against an upper cam 74 formed in the inside of the nose piece 18 so that rotation of the nose piece 18 relative to the remainder of the lower assembly 14 will cause the regulator piston to axially translate upwardly and downwardly, depending on the direction of rotation. In this way, the valve stem 60 can be caused to lower against the ball 50 of the regulator valve assembly to allow the user to rotate the nose piece to both turn on and off the flow as well as to regulate the flow to a desired rate, generally within the ranges set forth above. Additional over-pressure failure modes may be provided in the nose piece in order to prevent gas to flow through the fitted end 20 when exposed to excess pressure. For example, the O-ring 66 may be selected to have properties which will fail in response to pressure above a pre-determined threshold. Alternatively, the O-ring 43 (FIGS. 4 and 5) disposed over nosepiece nut 42 could be selected to have properties which fail in response to such over-pressure.

Referring now to FIGS. 7A-7C, operation of the hand-held dispenser of the present invention will be described in greater detail. Initially, as shown in FIG. 7A, the needle 44 is held in the disc spring 46 with the disc spring in an advanced (convex) configuration (i.e., flipped so that the needle is held in a relatively advanced configuration relative to the septum 26). As the upper assembly 16 is rotated, a threaded lower end 41 of the regulator body 40 will translate downwardly on the threaded neck 28 of the lower assembly 14. This causes the needle 44 to move downwardly and to penetrate into the septum 26, as shown in FIG. 7B. Simultaneously, the disc spring 46 will engage the upper surface of the threaded neck 38, causing the disc spring to invert to assume a retracted (concave) configuration, as shown in FIG. 7B. This causes the needle, which has penetrated the septum, to move upwardly from the septum to leave an annular flow orifice 76 surrounding the needle 44, allowing gas to flow from the cartridge 24 upwardly.

Flow from the cartridge, however, will continue to be blocked by ball valve 50 so long as it remains seated in seat 56, as shown in FIG. 7B. To open the valve and allow flow, the nose piece 18 is rotated to cause cams 72 and 74 to lower the regulator piston 62 to cause the valve stem 60 to push the ball valve 52 downward, as shown in FIG. 7C. At this point, an open flow path through the port and fitted end 20 is created, and gas will flow upwardly as shown by the arrows in FIG. 7C. The rate of gas flow can be finely adjusted by the user by rotating the nose piece 18. The flow may be shut off entirely by fully rotating the nose piece so that the valve stem 60 allows spring 52 to push the ball 50 back against seat 56, again as shown in FIG. 7B.

While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.

Claims

1. A hand-held, low-flow gas dispenser comprising:

an enclosure having a gas outlet;

a pressurized gas cartridge having a penetrable septum within the enclosure;

a pin having a tip for penetrating the septum;

a pin carrier adapted to advance the pin through the septum to form a hole and to retract the pin from the hole to allow gas flow from the cartridge, wherein the pin is prevented from reentering the hole; and

a flow control valve in series with but separate from the pin and pin carrier for selectively controlling the flow rate of gas released from the cartridge.

2. A dispenser as in claim 1, wherein the pin carrier comprises a bistable mechanism which is shifted from an advanced configuration to a retracted configuration after the carrier advances a predetermined distance.

3. A dispenser as in claim 2, wherein the bistable mechanism comprises a spring.

4. A dispenser as in claim 1, wherein the pressurized gas cartridge is removably disposed in the enclosure.

5. A dispenser as in claim 1, wherein the pressurized gas cartridge is non-removably disposed in the enclosure.

6. A dispenser as in claim 1, wherein the pin has a solid core.

7. A dispenser as in claim 6, wherein the pin has a width in the range from 0.5 mm to 2 mm.

8. A dispenser as in claim 1, wherein the pin carrier comprises a bistable spring having an advanced configuration and a retractable configuration.

9. A dispenser as in claim 1, wherein the flow control valve comprises a spring-loaded ball valve with a rotatable stem for opening the valve against the spring.

10. A dispenser as in claim 9, wherein the flow control valve is calibrated to deliver gas at a flow rate in the range from 1 cc/sec to 50 cc/sec

11. A dispenser as in claim 9, wherein the flow control valve is located in the enclosure between the gas cartridge and the outlet.

12. A dispenser as in claim 9, wherein the flow control valve is located in a neck of the gas cartridge.

13. A dispenser as in claim 1, wherein the outlet is adapted to seal against a nostril.

14. A dispenser as in claim 1, further comprising means for redirecting away from the gas outlet gas flow in the event of overpressure of the gas cartridge.

15. A dispenser as in claim 14, wherein the means comprises a failure weld in a component exposed to pressure from the gas cartridge when the flow control valve is closed.

16. A dispenser as in claim 14, comprising a gasket between the gas cylinder and the enclosure, wherein the gasket extrudes in response to overpressure when the flow control valve is closed.

17. A dispenser as in claim 14, comprising an O-ring above the flow control valve which fails in response to overpressure when the flow control valve is open.

18. A method for dispensing low-flow rate gas from a hand-held dispenser, said method comprising:

penetrating a pin through a septum on a gas cartridge in the dispenser to create a hole;

retracting the pin from the hole to permit gas flow through the hole to an outlet on the dispenser, wherein the pin is prevented from reentering the hole; and

adjusting a separate valve on the dispenser to control the flow rate of the gas through an outlet on the dispenser.

19. A method as in claim 18, wherein the pin is mounted on a pin carrier which shifts from an advanced configuration to a retracted configuration as the pin or carrier engages a stop in the dispenser.

20. A method as in claim 19, wherein the carrier comprises a bistable spring which springs from the advanced to retracted configurations.

21. A method as in claim 18, wherein the gas is a therapeutic gas.

22. A method as in claim 21, wherein the therapeutic gas comprises carbon dioxide.

23. A method as in claim 22, wherein the gas comprises at least 50% carbon dioxide by volume.

24. A method as in claim 18, wherein the valve is adjusted to control flow at a rate from 1 cc/sec to 50 cc/sec

25. A method as in claim 18, wherein adjusting comprises a rotating nose piece which adjusts the position of a spring-loaded ball valve.

26. A method as in claim 18, wherein the spring-loaded ball valve is disposed between the gas cartridge and the outlet.

27. A method as in claim 18, wherein the spring-loaded ball valve is disposed in the cartridge.

28. A method as in claim 18, further comprising redirecting gas flow away from the gas outlet in the event of overpressure of the gas cartridge.

29. A method as in claim 28, wherein redirecting comprises at least one of ring failure, gasket failure, and component weld failure.

30. A method for manufacturing a low-flow rate gas dispenser, said method comprising:

providing an enclosure having an outlet, a septum-penetrating pin, and a control valve stem;

providing a gas cartridge having a penetrable septum and a spring-loaded valve; and

assembling the gas cartridge and the enclosure so that the pin is located adjacent the septum and the control valve stem can engage the spring-loaded valve after the septum has been penetrated.