Free flow aerosol valves

• US 5,772,085 A
• Filed: 03/08/1996
• Issued: 06/30/1998
• Est. Priority Date: 03/10/1995
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Bryant, Andrew M., Miller, Nicholas C., Hodson, Peter D.
• Primary Examiner(s): Huson, Gregory L.
• Application Number:
  US08/612,593
• Time in Patent Office: 844 Days
• Field of Search: 222/402.2, 222/162
• US Class Current: 222/402.2
• CPC Class Codes: A61M 15/0091 mechanically breath-triggered
• CPC Class Codes: A61M 15/0095 Preventing manual activation in absence of inhalation
• CPC Class Codes: B65D 83/14 for delivery of liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant for a product delivered by a propellant
• CPC Class Codes: B65D 83/425 Delivery valves permitting filling or charging
• CPC Class Codes: B65D 83/54 Metering valves ; Metering valve assemblies

Abstract

A metered dose dispensing valve is described that is particularly suitable for dispensing metered volumes of a pressurised aerosol formulation. The valve comprises a chamber, and a valve stem extending into the chamber and movable relative to the chamber between non-dispensing and dispensing positions. The valve stem has a configuration and the chamber has an internal configuration such that a metered volume is defined therebetween and such that during movement between its non-dispensing and dispensing positions the valve stem sequentially: (i) allows free flow of aerosol formulation into the chamber, (ii) defines a closed metered volume for pressurised aerosol formulation between the external surface of the valve stem and internal surface of the chamber, and (iii) moves with the closed metered volume within the chamber without decreasing the volume of the closed metered volume until the metered volume communicates with an outlet passage thereby allowing dispensing of the metered volume of pressurised aerosol formulation.

Claims

1. A metered dose dispensing valve for dispensing metered volumes of a pressurized aerosol formulation, the valve comprising:

a chamber,

an outlet passage and

a valve stem extending into the chamber and movable relative to the chamber between non-dispensing and dispensing positions, the valve stem having a configuration including an external surface and the chamber having an internal configuration including an internal surface such that a movable metered volume of pressurized aerosol formulation is capable of being defined therebetween and such that during movement between its non-dispensing and dispensing positions the valve stem sequentially;

(i) allows free flow of aerosol formulation into and out of the chamber,

(ii) defines a closed metered volume for pressurized aerosol formulation between the external surface of the valve stem and internal surface of the chamber, and

(iii) moves with the closed metered volume within the chamber without decreasing the volume of the closed metered volume until the metered volume communicates with the outlet passage thereby allowing dispensing of the metered volume of pressurized aerosol formulation.

2. A dispensing valve according to claim 1 comprising a housing having a wall defining the chamber, the chamber having an outlet and an inlet having dimensions sufficient to allow free flow of aerosol formulation into and out of the chamber depending upon the orientation of the valve under the effect of gravity without the flow of aerosol formulation being significantly impeded,

the valve stem comprising first and second sealing surfaces longitudinally spaced, each sealing surface capable of forming a gas-tight seal with the wall of the chamber, the valve stem and the chamber being configured such that during movement of the valve stem between the non-dispensing and dispensing positions the valve stem sequentially passes:

(i) a priming position in which the inlet is open allowing free access of aerosol formulation to the chamber and the first sealing surface prevents access of aerosol formulation to the outlet,

(ii) a metering position in which the second sealing surface blocks the inlet and the first sealing surface prevents access of aerosol formulation to the outlet, thereby defining a closed metered volume between the first and second sealing surfaces and the wall of the chamber,

(iii) a shuttling stage during which the valve stem moves with the closed metered volume within the chamber without decreasing the volume of the closed metered volume, to

(iv) a dispensing position in which the first sealing surface is positioned to allow access of aerosol formulation to the outlet.

3. A metered dose dispensing valve according to claim 1 wherein said closed metered volume remains at constant volume during movement to the dispensing position.

4. A metered dose dispensing valve according to claim 2 wherein said sealing surfaces comprise sealing elements having one or more lobes, tapered projections or an annular skirt in contact with the wall of the chamber to facilitate sealing without incurring high frictional forces.

5. A metered dose dispensing valve according to claim 4 wherein the sealing elements comprise a central cylindrical portion having an annular skirt inclined with respect to said central cylindrical portion which forms a circumferential sealing surface, said skirt being resiliently flexible such that pressure applied to one side of the skirt urges the circumferential sealing surface radially outwardly to facilitate sealing and pressure applied to the other side of the skirt deflects the circumferential sealing surface radially inwardly.

6. A metered dose dispensing valve according to claim 4 wherein said sealing elements are retained within circumferential grooves on the valve stem and said grooves are configured to provide free space to accommodate movement of said sealing elements when they are deformed.

7. A metered dose dispensing valve according to claim 1 wherein said valve stem comprises at least one recess and the wall of the chamber comprises an elastomeric sealing surface making a gas-tight seal with the valve stem, said sealing surface extending longitudinally a greater distance than said recess on the valve stem whereby said closed metered volume is defined by said recess and said sealing surface.

8. A metered dose dispensing valve according to claim 7 wherein said wall of the chamber is formed of elastomeric sealing material retained by upper and lower support members and said elastomeric sealing material comprises fins bearing against at least one of the support members to allow flexing of the sealing material.

9. A metered dose dispensing valve according to claim 2 wherein said valve stem comprises at least one recess positioned between said first and second sealing surfaces such that said closed metered volume is defined between said recess, said first and second sealing surfaces and the wall of the chamber.

10. A metered dose dispensing valve according to claim 2 wherein a spray orifice is integrally formed with said outlet passage or is in communication with said outlet passage to allow aerosol formulation to be dispensed as a spray.

11. A metered dose dispensing valve according to claim 1 wherein said valve stem moves inwardly from its non-dispensing to dispensing position.

12. A metered dose dispensing valve according to claim 1 wherein said valve stem moves outwardly from its non-dispensing to dispensing position.

13. A metered dose dispensing valve according to claim 2 wherein said valve stem is biased to its dispensing position or nondispensing position by a spring or pressure generated by said aerosol formulation.

14. A metered dose dispensing valve according to claim 1 wherein said valve stem is capable of rotary movement between its non-dispensing and dispensing positions.

15. A metered dose dispensing valve according to claim 1 fitted on an aerosol container wherein said aerosol container contains pressurized aerosol formulation.

16. A metered dose dispensing valve and container according to claim 15 in the form of an inhaler wherein the aerosol formulation comprises medicament.

17. A metered dose dispensing valve and container according to claim 16 wherein the inhaler comprises patient inhalation means responsive to patient inhalation, actuation means to move the valve stem to its dispensing position and triggering means responsive to the patient inhalation means such that the actuation means is triggered by patient inhalation.

18. A valve according to claim 2 comprising means to allow aerosol formulation to be pressure-filled through said outlet passage or a pressure filling port located in the valve stem.