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US 2003/0192917 A1Published application
Valves for Dispensers
AssigneeBespak PLC
InventorsChristopher John Eames, Martin Alan Nash
Life of this patent
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AssigneeBespak PLC
InventorsChristopher John Eames, Martin Alan Nash
Estimating the term…
A metering valve includes a valve stem co-axially slidable within a chamber body. The chamber body and the valve stem define a metering chamber. An outer and an inner annular seal is provided operative between a respective outer end and an inner end of the chamber body and the valve stem to seal the annular metering chamber there between. The inner seal comprises a wiper element.
A metering valve comprising a valve stem co-axially slidable within a chamber body, said chamber body and said valve stem defining a metering chamber, an outer and an inner annular seal being provided operative between a respective outer end and an inner end of the chamber body and the valve stem to seal the annular metering chamber there between, wherein the inner seal comprises a wiper element.
A metering valve comprising a valve stem having at one end a piston extending within and slidable relative to a cup shaped chamber body, a clearance being provided between an outer surface of the piston and an inner surface of the chamber body to provide a path for product, a spring urging the piston against a base of the chamber body, movement of the valve stem against the spring bias causing the piston to move away from the base of the chamber body to define a temporary metering chamber between the valve stem and chamber body, the metering valve further comprising a sealing member provided such that as an end of the piston moves into contact with the sealing member the flow of product along the path is prevented and the product is dispensed through an outlet in the valve stem, wherein the sealing member comprises a wiper element.
A method of pressure filling a dispensing apparatus of the type comprising a metering valve closing off a dispensing container, the metering valve comprising a valve stem co-axially slidable within a chamber body, said chamber body and said valve stem defining a metering chamber, an outer and an inner annular seal being provided operative between a respective outer end and an inner end of the chamber body and the valve stem to seal the annular metering chamber there between, wherein the inner seal comprises a wiper element, the method comprising:
Dependencies are inferred from the claim text.
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Valves specially adapted for the discharge of contents; Regulating devices: metering valves; Metering devices
Filling or charging means: delivery valves permitting filling or charging
Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid…
Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid…
Term end not estimated
The present application claims priority under 35 USC 119(a)-(d) to UK Patent Application No. 0203657.2 filed in Great Britain on Feb. 15, 2002, which application is hereby incorporated herein by reference.
Metering valves typically comprise a valve stem co-axially slidable within a chamber body. The chamber body and the valve stem define a metering chamber for metering, in use, the product to be dispensed on each actuation of the apparatus. Outer and an inner annular seals are provided operative between a respective outer end and an inner end of the chamber body and the valve stem to seal the annular metering chamber there between. One problem with such metering valves is that in order for a good seal to be obtained between the seals and the valve stem it is necessary for the seals to tightly engage the valve stem. This can lead to a problem known as “seat drag” wherein on operation of the valve stem the seals are displaced axially due to the resulting friction. Over time seat drag can distort the shape of the seals leading to a reduction in integrity of the seal with the valve stem and also to potential changes in the volume of the metering chamber. A further problem is that the valve stem can be prone to sticking to the seals requiring a high actuation force to start the valve stem moving. The “unstick” force required to move the valve stem can be variable between actuations. This can lead to inconsistency in operation of the apparatus, especially where the actuation is designed to be automatic or semi-automatic such as in a breath actuated device.
The invention relates to improvements in valves for dispensers for dispensing an accurately metered dose of a product.
FIG. 1 shows a cross-sectional view of a first embodiment of dispensing apparatus according to the present invention in an actuated position.
FIG. 2 shows a cross-sectional enlarged view of a part of the dispensing apparatus of FIG. 1 in a non-actuated position.
FIG. 3 shows a cross-sectional view of a second embodiment of dispensing apparatus according to the present invention in a non-actuated position.
A first embodiment of dispensing apparatus 10 according to the present invention is shown in FIGS. 1 and 2. The dispensing apparatus comprises a metering valve 10 which is attached in use to a pressurized dispensing container (not shown) in which a product to be dispensed in metered doses is stored. The product may be a liquid or a medicament normally in suspension or other excipients or a product which is expelled using a liquefied propellant such as a CFC or HFA or blends thereof.
The metering valve 10 is held in position to seal the dispensing container by a ferrule 13 which is crimped to the open neck of the container. An elastomeric sealing gasket 34 prevents leakage of the product between the ferrule 13 and container. The metering valve comprises a valve stem 15 which extends co-axially within a generally cup-shaped chamber body 16 so as to be externally accessible. The metering valve further comprises a valve body 17 which supports the chamber body 16 within the metering valve 10.
The chamber body 16, which is made preferably of a polymeric material, has a base 20 in which is located an aperture 21 and side walls 22 defining the open end of the chamber body 16. Sandwiched between the base 20 of the chamber body 16 and the ferrule 13 is an elastomeric sliding seal 23 which also has an aperture therein.