GB2631709A

GB2631709A - Liquid metering dispensing apparatus and method of metering thereof

Info

Publication number: GB2631709A
Application number: GB2310538.0A
Authority: GB
Inventors: Allwright Julia
Original assignee: Athos Medical Tech Ltd
Current assignee: Athos Medical Tech Ltd
Priority date: 2023-07-10
Filing date: 2023-07-10
Publication date: 2025-01-15
Also published as: WO2025012628A1

Abstract

A liquid metering dispensing apparatus for dispensing a metered liquid comprises a cylinder 20 within which is an axially slidable assembly comprising a metering tube 4 and a piston 3. The assembly divides the cylinder into a metering chamber 21 having a closable liquid inlet 13-15 and a dispensing chamber 22 having a closable air inlet 18. Wherein movement of the assembly in a first direction causes movement between the metering tube and the piston, the liquid inlet to close and the air inlet to open so that differential air pressure causes the liquid to be displaced into the metering tube. Movement of the assembly in a second opposite direction causes relative displacement between the metering tube and piston to admit air within the dispensing chamber to enter the metering tube and isolate a metered dose of liquid. A heating element may be provided. A method of operating the apparatus is also provided.

Description

LIQUID METERING DISPENSING APPARATUS AND METHOD OF METERING THEREOF

This invention relates to a liquid metering dispensing apparatus and method of operating thereof In particular, the apparatus is intended for use as an inhaler or vaping device, although is not limited thereto.

With a medicinal inhaler or personal vaporizer, it is required to dispense a precise, metered, quantity of a liquid.

It is known from US-A-7222755 to provide a liquid metered dispensing squeezable bottle containing a dip tube and a one-way valve system at the bottom of the dip tube. The dip tube includes a leg that is flexible to permit folding of the leg toward the container for insertion into a standard neck or narrow neck container.

US-A-8091741 discloses a dip tube in a fluid dispenser being replaced by a hollow fibre membrane that is able to pass liquid under the influence of a pressure differential, whereby liquid in contact with the hollow fibre membrane passes through the wall of the membrane and travels internally along the length of the membrane to a dispenser -the object being to provide the dispenser with the capability of operating at any orientation.

US 2016/0255880 discloses an aerosol generating device that includes a vaporizer for heating an aerosol-forming substrate and a capillary material for conveying the liquid aerosol-forming substrate from a storage container towards a vaporizer by capillary action with a porous material being positioned between the capillary material and the vaporizer.

The present invention seeks to provide an apparatus and method of operating thereof in which a uniform dose is metered from a liquid reservoir and to prevent thermal degradation of the metered dose and prevent the bulk reservoir from exposure to the heating process.

According to this invention in its broadest aspects, there is provided a liquid metering dispensing apparatus for dispensing a metered liquid comprising a cylinder (20) within which is an axially slidable assembly comprising a metering tube (4) and a piston (3) arranged to be movable in respect to the metering tube, said assembly dividing the cylinder into a metering chamber (21) having a closable liquid inlet (13 -15) and a dispensing chamber (22) having a closable air inlet (18), wherein movement of the assembly in a first direction causes movement between the metering tube and the piston, the liquid inlet to close and the air inlet to open so that differential air pressure causes the liquid to be displaced into the metering tube, and movement of the assembly in a second opposite direction causes relative displacement between the metering tube and the piston to admit the air within the dispensing chamber to enter the metering tube to isolate a metered dose of liquid.

According to this invention in one aspect there is provided a liquid metering dispensing apparatus for dispensing a metered liquid comprising a cylinder (20) having, at one end, a nozzle (15) for introducing the liquid into the cylinder, said nozzle (15) being selectively closable by a spring (12) operated first valve (13) and having a closed end opposite said one end, said one end having at least one air differentially operated second valve (18) for admitting a nto said cylinder, a reciprocal movable piston (3) biased by said spring (12) located in said cylinder, said piston (3) dividing said cylinder (20) into a metering chamber (21) and a dispensing chamber (22), and a metering tube reciprocally located through said closed end of the cylinder arranged to move said piston (3) and also selectively close said first valve (13), said metering tube (4) including at least one metering hole (4) and, displaced along a vertical axis of said metering tube, at least one dispensing hole (8), whereby, in operation, the liquid to be dispensed is brought into contact with said nozzle (15) and said liquid fills said metering chamber (21), a force is exerted on said metering tube (4) to move said piston (3) to close the at least one dispensing hole (8), further movement of said piston (3) closes said first valve (13) and opens said at least one metering hole (9) and differential pressure opens the at least one second valve to admit air nto said displacement chamber (22), and relaxation of said force enables the spring (12) to move the piston (3) to close the at least one metering hole (9), open the at least one dispensing hole (8) and close the second valve (18) so that air flows into the metering tube (4) to isolate a metered dose of liquid.

Preferably, heating means (5) is provided to vaporize said metered dose.

Conveniently, the heating means includes an energy source arranged to heat an electric element.

Advantageously, said electrical element is made of an electrically resistive material such as doped ceramics, molybdenum disilicide carbon, graphite, metal, quartz or composite materials made of a ceramic material and a metallic material.

Alternatively, the heating element could be an infrared heating element, a photonic source or an inductive heating element.

Preferably, the heating means is arranged to convert the metered liquid dose into vapor droplets of 2 -5microns, but may be less than 2 microns for systematic absorption.

Advantageously, the heating means has a temperature in the range 20°C -200°C, usually 30°C -90°C, and preferably, 60°C.

Preferably, the first valve is a ball valve (13).

Advantageously, the capillary means is a hollow fibre membrane made from a group consisting of polytetrafluoroethylene, polyamide, polysulfone, polyethersulfone, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polyvinyl pyrrolidone, polycarbonate, polyacrylonitrile, cellulose, cellulose acetate, mixtures, blends and co-polymers thereof.

Advantageously, the liquid is a medicament, or nicotine, plus an excipient including propylene glycol, vegetable glycerine, or an organic solvent such as ethanol.

In another aspect of this invention, there is provided a method of operating the apparatus of said one aspect, wherein said nozzle (15) is brought into contact with capillary means (16) inside a reservoir (17) contacting the liquid to be metered and vaporized including the steps of exerting pressure on said metering tube (4) to move said piston (3) to close the at least one dispensing hole (8), further movement of said piston (3) closing said first valve (13) and opening said at least one metering hole (9) and differential pressure opening the at least one second valve to admit air into said displacement chamber (22), relaxing said force to enable the spring (12) to move the piston (3) to close the at least one metering hole (9), opening the at least one dispensing hole (8) and closing the second valve (18) so that air flows into the metering tube (4) to isolate a metered dose of liquid.

Preferably, said nozzle (15) is brought nto contact with capillary means (16) inside a reservoir (17) contacting the liquid to be metered and vaporized.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1 -5 show cross-sectional views of a liquid metering dispensing apparatus in accordance with this invention in differing operational positions but with the heating element, mouthpiece, liquid reservoir and hollow fibre membrane being shown in Figure 1 only for clarity, and Figures 6a -6c each show a differing heating element that may be used with the apparatus.

In the Figures like reference numerals denote like parts.

Referring to Figure 1, the liquid metering dispensing apparatus 1 has a cylinder 20 forming a lower metering chamber 21 and an upper dispensing chamber 22 with reciprocally movable a piston 3 disposed between the chambers 21 and 22. Thus, the apparatus has dual chambers, one for metering and the other for dispensing. Within the piston 3 is a metering tube 4. An upper end of the metering tube 4 is in communication with a heating element 5 for vaporizing liquid and vaporized liquid is withdrawn by a user from a mouthpiece 6.

The heating element 5 is connected to an energy source, such as a battery (not shown).

The heating element may comprise a single heating element or a plurality arranged suitably to effectively heat and vaporize the liquid.

The heating element may be in the form of a cylinder (as shown in Figure 6a), a flattened cylinder (as shown in Figure 6b) or a disc (as shown in Figure 6c), all being apertured and made of an electrically resistive material such as doped ceramics, molybdenum disilicide carbon, graphite, metal, quartz or composite materials made of a ceramic material and a metallic material, the apertures admitting the metered dose for vaporization.

Alternatively, the heating element could be an infrared heating element, a photonic source or an inductive heating element. Further, an anti-oxidation coating such as Apticote 810 may be applied to the heating element surface to prevent harmful toxins forming.

The heating element may produce heat in the range 20°C -200°C usually in the range 30° -90° C and, in a preferred embodiment, 60°C, but the temperature is drug-dependent.

At an upper end of the cylinder 20 is a wall in which is one or more umbrella valves 18.

A mid-portion of the metering tube 4 has external abutments 7 for contacting an upper end of the piston 3 and below (as shown in the Figures) are a plurality of dispensing holes 8, four equ -spaced dispensing holes being used in the Figures 1 -5.

Below the dispensing holes 8 are a plurality of metering holes 9, four equicircumferentially spaced metering holes being used in Figures 1 -5. The metering tube 4 has an enlarged diameter lower end 10 providing a shoulder 11 for contact with a lower portion of the piston 3. Located within the lower end 10 is a compression spring 12 abutting an upper wall closing the lower end, and at a lower end of the compression spring 12 is a ball valve 13 located in a funnel portion 14 of a nozzle 15. In use, the nozzle 15 is arranged to communicate, by for example, being a push fit, with a hollow fibre membrane 16 located in a liquid reservoir 17 containing a liquid which may be a drug for administration to a user. The drug may be one of a medicament or nicotine, plus or an excipient including propylene glycol, vegetable glycerine, or an organic solvent such as ethanol. The excipients may be [100/0 PG/VG or VG/PG] to [50/50 PG/VG] & include up to 30% ethanol.

The hollow fibre membrane forms a dip tube and is preferred since it enables independence of the nozzle orientation. The hollow fibre membrane may be selected from a group consisting of polytetrafluoroethylene, polyamide, polysulfone, polyethersulfone, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polyvinyl pyrrolidone, polycarbonate, polyacrylonitrile, cellulose, cellulose acetate, mixtures, blends and co-polymers thereof. Preferred tubes have a pore size in the range 0.01microns to 250microns, the precise pore size, wall thickness and length being selected according to the liquid to be dispensed.

The number and size of the dispensing holes 8 and metering holes 9 also depend upon the liquid being dispensed.

In operation, in the position shown in Figure I, the apparatus is ready to measure a metered dose of liquid from the reservoir 17 and the ball valve 13 is open so that liquid flows via capillary action through the hollow fibre membrane 16 into the metering chamber 21.

When the metering tube 4 is pressed downwardly, as shown by arrow-headed line 31, shown in Figure 2, so the abutments 7 on the metering tube 4 contact an upper (as shown in Figure 2) end of the piston 3 to move the piston downwardly. This causes the dispensing holes 8 to close and the metering holes 9 to open.

As shown in Figure 3, as the metering tube 4 is pressed downwardly further, the ball valve 13 moves downwardly, as shown by arrow-headed line 32, and the ball valve closes the nozzle 15 and liquid flows through the metering holes 9 into the dispensing chamber 22, as shown by broken arrow-headed lines 33 through differential air pressure. The differential air pressure also causes the umbrella valves 18 to open so that air flows into the dispensing chamber 22, as shown by broken arrow-headed lines 34.

Referring to Figure 4, when downward pressure on the metering tube is released, so the umbrella valves 18 close and the compression spring urges the piston 3 upwardly, as shown by arrow-headed lines 35, to close the metering holes 9 and open the dispensing holes 8, thereby admitting air nto the metering tube 4 as shown by broken arrow-headed lines 36.

As shown in Figure 5, as the end of the piston 3 is moved upwardly and the ball valve opens, so the air 36 admitted through metering holes 9 isolate a metered dose 37 and the liquid reservoir 17 is protected from thermal degradation created by the heating element 5.

The metered dose is drawn through the heating element 5 by a user sucking on the mouthpiece 6, the heating element vaporizing the liquid so that a user nhales vapor.

The particle size of the vaporized liquid may be 2 -5microns, or less than 2 microns for systematic absorption.

The volume capacity of the liquid reservoir may be in the range 2-10m1 and the quantity dispensed may be 0.5m1.

The volume capacity of the metering chamber may be in the range 10 -1600, preferably 10 -400 for salbutamol.

The heating element is arranged to suit the formulation properties, drug volume and particle size distribution.

The cylinder 20 and piston 3 may be made of plastics/polymer, metal or metal alloy. The umbrella valves may be made of plastics/polymer or rubber. The liquid reservoir 17 may be made of plastics/polymer, metal, metal alloy, polycarbonate or glass.

In this specification an apparatus/method/product "comprising" certain features is intended to be interpreted as meaning that it includes those features. but that it does not exclude the presence of other features.

Many variations are possible without departing from the scope of the present invention as defined in the appended claims.

Claims

CLAIMS1. A liquid metering dispensing apparatus for dispensing a metered liquid comprising a cylinder (20) within which is an axially slidable assembly comprising a metering tube (4) and a piston (3) arranged to be movable in respect to the metering tube, said assembly dividing the cylinder into a metering chamber (21) having a closable liquid inlet (13 -15) and a dispensing chamber (22) having a closable air inlet (18), wherein movement of the assembly in a first direction causes movement between the metering tube and the piston, the liquid inlet to close and the air inlet to open so that differential air pressure causes the liquid to be displaced into the metering tube, and movement of the assembly in a second opposite direction causes relative displacement between the metering tube and the piston to admit the air within the dispensing chamber to enter the metering tube to isolate a metered dose of liquid.
2. A liquid metering dispensing apparatus as claimed in claim 1, for dispensing a metered liquid comprising the cylinder (20) having, at one end, a nozzle (15) for introducing the liquid into the cylinder, said nozzle (15) being selectively closable by a spring (12) operated first valve (13) and having a closed end opposite said one end, said one end having at least one air differentially operated second valve ( I 8) for admitting air into said cylinder, the reciprocal movable piston (3) being biased by said spring (12) located in said cylinder, said piston (3) dividing said cylinder (20) into the metering chamber (21) and the dispensing chamber (22), and the metering tube reciprocally located through said closed end of the cylinder arranged to move said piston (3) and also selectively close said first valve (13), said metering tube (4) including at least one metering hole (4) and, displaced along a vertical axis of said metering tube, at least one dispensing hole (8), whereby, in operation, the liquid to be dispensed is brought into contact with said nozzle (15) and said liquid fills said metering chamber (21), a force is exerted on said metering tube (4) to move said piston (3) to close the at least one dispensing hole (8), further movement of said piston (3) closes said first valve (13) and opens said at least one metering hole (9) and differential pressure opens the at least one second valve to admit air into said displacement chamber (22), and relaxation of said force enables the spring ( I 2) to move the piston (3) to close the at least one metering hole (9), open the at least one dispensing hole (8) and close the second valve (18) so that air flows into the metering tube (4) to isolate a metered dose of liquid.
An apparatus as claimed in claim 2, wherein heating means (5) is provided to vaporize sa d metered dose.
4. An apparatus as claimed in claim 3, wherein the heating means includes an energy source arranged to heat an electric element.
5. An apparatus as claimed in claim 4, wherein said electrical element is made of an electrically resistive material such as doped ceramics, molybdenum disilicide carbon, graphite, metal, quartz or composite materials made of a ceramic material and a metallic material.
6. An apparatus as claimed in claims 3 or 4, wherein the heating means is arranged to convert the metered liquid dose into vapor droplets of 2 -5microns, or less than 2 microns for systematic absorption.
7. An apparatus as claimed in claims 3 -6, wherein the heating means has a temperature in the range 20°C -200°C, usually 30°C -90°C, and preferably, 60°C.
An apparatus as claimed in claim 2, wherein the first valve is a ball valve (13).
9. An apparatus as claimed in any preceding claim, the liquid is a medicament, or nicotine, plus an excipient including propylene glycol, vegetable glycerine, or an organic solvent such as ethanol.
10. A method of operating the apparatus claimed in any preceding claim, wherein said nozzle (15) is brought into contact with capillary means (16) inside a reservoir (17) contacting the liquid to be metered and vaporized including the steps of exerting pressure on said metering tube (4) to move said piston (3) to close the at least one dispensing hole (8), further movement of said piston (3) closing said first valve (13) and opening said at least one metering hole (9) and differential pressure opening the at least one second valve to admit air nto said displacement chamber (22), relaxing said force to enable the spring (12) to move the piston (3) to close the at least one metering hole (9), opening the at least one dispensing hole (8) and closing the second valve (18) so that air flows into the metering tube (4) to isolate a metered dose of liquid.
11. A method of operating the apparatus of claiml 0, wherein said nozzle (15) is brought into contact with capillary means (16) inside a reservoir (17) contacting the liquid to be metered and vaporized.
12. A method as claimed in claim I I, wherein the capillary means is a hollow fibre membrane made from a group consisting of polytetrafluoroethylene, poly-amide, polysulfone, polyethersulfone, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polyvinyl pyrrolidone, polycarbonate, polyacrylonitrile, cellulose, cellulose acetate, mixtures, blends and co-polymers thereof
13. A method as claimed in claim10 -12, wherein the liquid is a medicant, or a medicament plus or nicotine, plus or an excipient including propylene glycol, vegetable glycerine, or an organic solvent such as ethanol.