A liquid delivery device with a one-way valve

Abstract

A Liquid Delivery Device With A One-Way Valve A liquid delivery device comprises a lower housing part configured to contain a collapsible reservoir and an upper housing part configured to contain a nozzle assembly and metering chamber, the metering chamber located at the inner or upstream end of the nozzle assembly, the nozzle assembly configured to convert liquid received from the metering chamber to a droplet spray at the outer or downstream end for delivery to a user, a passage extending between the reservoir and the metering chamber to in use deliver liquid from the collapsible reservoir to the metering chamber, and a one-way valve located in the passage between the metering chamber and the nozzle assembly, the one-way valve configured to open to allow liquid to pass from the metering chamber to the nozzle assembly, the valve in the closed position substantially blocking the passage to prevent the flow of gases and fluids into the collapsible reservoir.

Description

[0001] A LIQUID DELIVERY DEVICE WITH A ONE-WAY VALVE

[0002] TECHNICAL FIELD

[0003] The present invention relates to a liquid delivery device with a one-way valve. More particularly, the present invention relates to a nebuliser comprising a nozzle assembly with a one-way valve. Even more particularly, the present invention relates to a drug delivery device comprising a nozzle assembly with a one-way valve.

[0004] BACKGROUND

[0005] Drug delivery devices such as nebulisers are used to produce an aerosol of droplets for inhalation through the mouth and pharyngeal cavity into the lungs of a patient, for nasal administration, or for spraying the surface of the eye.

[0006] In a nebulising drug delivery device such as a soft mist inhaler (SMI), liquid pharmaceutical formulations are typically stored in a reservoir or ‘bag’ formed from a plastic material. From there, they are conveyed through a riser tube into a pressure chamber from where they are forced through a nozzle under pressure and atomised. In this way, drug delivery devices such as SMIs are able to nebulise a small amount of a liquid formulation according to the required dosage within a few seconds, to produce an aerosol suitable for therapeutic inhalation. Moreover, this can be achieved without requiring the use of a propellant, delivering an environmental benefit given the undesirable impact of propellants in climate change.

[0007] A typical, known, type of SMI or nebuliser device is shown in figure 1 . The device has an upper half that contains a nozzle, and a lower half that contains a collapsible reservoir or ‘bag’. A tube extends axially along the device from the nozzle to the reservoir. The upper and lower halves are rotated relative to one another in use to pump or prime the device. As the device is pumped (by rotating the two halves relative to one another), a pressure lower than atmospheric pressure is created in the pressure chamber which in turn is applied to the bag (suction) to pull liquid from the reservoir into the tube towards the nozzle, and the bag structure is pulled inwards (collapses inwards). For each individual use, the collapse is small, with each use adding incrementally to the overall full collapse of the bag at end-of-life. When the device is subsequently triggered by a user, a nebulised mist of product is delivered through the nozzle at the upper end of the device.

[0008] However, in devices of this type, even with a bag that has a thin wall, there is an inherent stiffness to overcome, and this increases as the bag empties. The bag is always ‘fighting’ the collapse caused by suction of the contents from the bag. The more resistance to collapse, the more resistance there is to drawing liquid up. As well as this, the nozzle creates an air leakage path from the exterior of the device to the interior. When the device is pumped or primed, liquid from the bag is drawn into and up the tube, but air can be drawn inwards through the nozzle, or by bypassing seals around the nozzle assembly. This impacts on the pressure differential created by pumping / priming the device, which impacts on the effectiveness of liquid being drawn from the bag to fill the chamber, and results in a reduction of the ability of the device to deliver a consistent or repeatable dose.

[0009] The air leakage path also provides an open route through the nozzle. Due to the open access to the environment, this can reduce the shelf-life, stability, and protection of the formulation.

[0010] The use of one-way valves in inhalers is known. US2021 / 0403550 describes and shows the use of a non-return valve 10 in an inhaler 1 , the valve 10 located in a capillary-style delivery tube 9 that runs between a liquid container 3, and a nozzle assembly that includes a nozzle 12. A similar arrangement is shown and described in US2021 / 0038837, where a non-return valve 21 is shown located in a capillary-style delivery tube 19 that runs between a fluid reservoir or container 12, and a pressure chamber 22, with the pressure chamber 22 located between the head of the delivery tube 19 and a nozzle assembly that includes a discharge nozzle 2.

[0011] US2012 / 0138049 describes and shows a valve 10 located in a capillary-style delivery tube 9, the passage 9 running between a fluid container 3 and a nozzle assembly that includes a nozzle 12. EP4154928 describes and shows a one-way valve 125 located in a capillary-style delivery tube or pipe 121 that runs between a reservoir 120 and a nozzle assembly 103, 131 , 132, 133.

[0012] In all of these prior art documents, the valve is shown located inside the thin, narrow fluid delivery tube. The valve is arranged to be open so that fluid can flow through the tube during the priming stage of operation, and closed during the firing or dispensing phase. The valve forms a key part of the pressure generating element of the micropump and is closed during the firing stroke such that liquid can be forced out of the metering chamber and through the nozzle.

[0013] A further issue that can occur with inhalers and nebulisers is that of the ‘start-up effect’. If the delivery pressure is built up gradually during operation, this tends to have the effect in use that larger and less-evenly-sized droplets are formed initially during the build-up phase. Larger droplets are less desirable as they are less respirable.

[0014] At the stage where the pressure reaches full operational force, small and evenly-sized droplets are delivered (which is more desirable). Similarly, if the delivery pressure ramps down slowly, then larger and less-evenly-sized droplets are produced at the end of the dose delivery event.

[0015] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. SUMMARY OF THE INVENTION

[0016] It is an object of the present invention to provide a liquid delivery device comprising a nozzle assembly with a one-way valve which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

[0017] It is a further object of the present invention to provide a nebuliser comprising a nozzle assembly with a one-way valve which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

[0018] It is a yet still further object of the invention to provide a drug delivery device comprising a nozzle assembly with a one-way valve which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

[0019] Accordingly, in a first aspect the present invention may broadly be said to consist in a liquid delivery device, comprising: a lower housing part configured to contain a collapsible reservoir; an upper housing part configured to contain a nozzle assembly and metering chamber, the metering chamber located at or towards the inner or upstream end of the nozzle assembly, the nozzle assembly configured to convert liquid received from the metering chamber to a droplet spray at the outer or downstream end for delivery to a user; a passage extending between the collapsible reservoir and the metering chamber to in use deliver liquid from the collapsible reservoir to the metering chamber; a one-way valve located in the passage between the metering chamber and the nozzle assembly, the one-way valve configured to open to allow liquid to pass from the metering chamber to the nozzle assembly, the valve in the closed position substantially blocking the passage to prevent the flow of gases and fluids into the collapsible reservoir.

[0020] In an embodiment, the one-way valve comprises a pressure responsive check valve.

[0021] In an embodiment, the one-way valve is configured to have an opening pressure of substantially O.lkPa.

[0022] In an embodiment, the one-way valve is configured to have a minimum opening pressure of substantially 50% of the minimum viable operating pressure of the liquid delivery device.

[0023] In an embodiment, the one-way valve is configured to have a minimum opening pressure of substantially 50% of the usual operating pressure of the liquid delivery device.

[0024] In an embodiment, the one-way valve is configured to have an opening pressure of substantially 400kPa.

[0025] In an embodiment, the one-way valve is configured to have an opening pressure of substantially 1 ,000kPa. In an embodiment, the one-way valve is configured to have an opening pressure of substantially 4,000kPa.

[0026] In an embodiment, the one-way valve comprises: a main body configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage; a blocking member configured to move within the passage from a first position where fluid flow through the passage is substantially blocked, to a second position where fluid can flow through the passage; a biasing mechanism configured to extend between the main body and the blocking member to bias the blocking member towards the first position.

[0027] In an embodiment, the main body is ring-shaped.

[0028] In an embodiment, the blocking member comprises a ball bearing.

[0029] In an embodiment, the biasing mechanism comprises a plurality of spring prongs.

[0030] In an embodiment, the spring progs are spaced at substantially equal intervals from one another.

[0031] In an embodiment, the biasing mechanism comprises three spring prongs.

[0032] In an embodiment, the spring prongs are angled inwards.

[0033] In an embodiment, the blocking member ends of the spring prongs are shaped to receive the blocking member.

[0034] In an embodiment, the blocking member comprises a flat sealing portion.

[0035] In an embodiment, the flat sealing portion has a chamfered edge.

[0036] In an embodiment, the spring mechanism comprises a plurality of spring members integrally formed with and extending from the main body.

[0037] In an embodiment, the spring members are spaced at substantially equal intervals from one another.

[0038] In an embodiment, the biasing mechanism comprises three members.

[0039] In an embodiment, the flat sealing portion and spring mechanism are integrally formed with the main body so that the one-way valve comprises a unitary item.

[0040] In an embodiment, the one-way valve comprises a flap valve.

[0041] In an embodiment, the one-way valve comprises: a blocking head configured to locate within the nebuliser passage so as to be movable between a first position where fluid flow through the passage is substantially blocked, and a second position where fluid can flow through the passage; a plurality of spring legs configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage, and to bias the blocking member towards the first position.

[0042] In an embodiment, the blocking head is dome-shaped.

[0043] In an embodiment, the blocking head has a conical shape.

[0044] In an embodiment, the blocking head is bullet-shaped.

[0045] In an embodiment, the spring legs have the form of castellations extending from the bottom side of the blocking head.

[0046] In an embodiment, the spring legs are angled away from one another.

[0047] In an embodiment, the spring legs are spaced at substantially equal intervals from one another.

[0048] In an embodiment, the one-way valve comprises four spring legs.

[0049] In an embodiment, the outer or free ends of the legs are thicker than the inner portion of the legs.

[0050] In an embodiment, the spring legs have a curved outer profile so that the curve of the legs conforms to the cross-sectional shape of the recess.

[0051] In an embodiment, the blocking head has a diameter of substantially 2.5mm.

[0052] In an embodiment, the main body comprises a flat lower face, and an upper face that has an inwardly-chamfered or curved outer edge, with an outer wall and inner wall that extend upwards substantially perpendicularly to the flat lower face.

[0053] In an embodiment, the blocking member comprises a disc-shaped member having a thickness substantially half that of the radius of the disc-shaped member, the upper and lower faces of the disc substantially flat and substantially parallel to one another.

[0054] In an embodiment, the biasing member comprises a plurality of pillars that extend and connect between the central sealing portion and the main body, the pillars extending upwards past the upper surfaces of the main body.

[0055] In an embodiment, the blocking member and biasing member are integrally formed with the main body so that the one-way valve comprises a unitary item.

[0056] In a second aspect the present invention may broadly be said to consist in a one-way valve for a liquid delivery device, comprising: a main body configured to locate within a passage within the liquid delivery device; a blocking member configured to move within the passage from a first position where fluid flow through the passage is substantially blocked, to a second position where fluid can flow through the passage; a biasing mechanism configured to extend between the main body and the blocking member to bias the blocking member towards the first position. In an embodiment, the main body is ring-shaped.

[0057] In an embodiment, the blocking member comprises a ball bearing.

[0058] In an embodiment, the biasing mechanism comprises a spring mechanism comprising plurality of spring prongs.

[0059] In an embodiment, the spring prongs are angled inwards.

[0060] In an embodiment, the blocking member ends of the spring prongs are shaped to receive the blocking member.

[0061] In an embodiment, the blocking member comprises a flat sealing portion.

[0062] In an embodiment, the flat sealing portion comprises a chamfered edge.

[0063] In an embodiment, the spring mechanism comprises a plurality of spring members integrally formed with and extending from the main body.

[0064] In an embodiment, the flat sealing portion and spring mechanism are integrally formed with the main body so that the one-way valve comprises a unitary item.

[0065] In a third aspect the present invention may broadly be said to consist in one-way valve for a liquid delivery device, comprising: a blocking head configured to locate within a passage within the liquid delivery device so as to be movable between a first position where fluid flow through the passage is substantially blocked, and a second position where fluid can flow through the passage; a plurality of spring legs configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage, and to bias the blocking member towards the first position.

[0066] In an embodiment, the blocking head is dome-shaped.

[0067] In an embodiment, the blocking head has a conical shape.

[0068] In an embodiment, the blocking head is bullet-shaped.

[0069] In an embodiment, the spring legs have the form of castellations extending from the bottom side of the blocking head.

[0070] In an embodiment, the spring legs are angled away from one another.

[0071] In an embodiment, the spring legs are spaced at substantially equal intervals from one another.

[0072] In an embodiment, the one-way valve comprises four spring legs.

[0073] In an embodiment, the outer or free ends of the legs are thicker than the inner portion of the legs. In an embodiment, the spring legs have a curved outer profile so that the curve of the legs conforms to the cross-sectional shape of the recess.

[0074] In an embodiment, the blocking head has a diameter of substantially 2.5mm. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

[0075] BRIEF DESCRIPTION OF THE DRAWINGS

[0076] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0077] Figure 1 shows a side view of a known, prior art type of manually-operated nebuliser that has an upper half and a lower half, the two halves rotated relative to one another in use to pump or prime the device for use.

[0078] Figure 2 shows a top perspective view of a known, prior art nebuliser similar to that of figure 1 , showing detail of a nozzle assembly located in the upper half.

[0079] Figure 3 shows a side schematic view of a generic nozzle assembly, showing general detail of the main parts of the nozzle assembly and their relative locations and connections.

[0080] Figure 4 shows a perspective side view of a liquid delivery device that in this form is a nebuliser device according to an embodiment of the present invention.

[0081] Figure 5 shows a perspective cutaway side view of the nebuliser device of figure 4 from the same angle, showing interior detail of the device, including the tube, nozzle, and a one-way valve, the bag not shown, the valve in this embodiment comprising a pressure responsive check valve.

[0082] Figure 6 shows a perspective close-up detail cutaway side view of the top end of the nebuliser device of figures 4 and 5, from the same angle as figures 4 and 5, showing detail of the nozzle assembly, the nozzle assembly comprising a nozzle retainer, a nozzle seal, a first filter and filter holder, a nozzle chip / filter, and a lower seal, all enclosed within a top nut that screws onto the upper end of an upper tube housing located within the upper housing, a tube shown extending through the upper tube housing, a one-way valve according to an embodiment of the invention located below the nozzle holder.

[0083] Figure 7 shows a perspective close-up detail cutaway side view of the nozzle assembly of the nebuliser device of figures 4, 5, and 6, from the same angle. Figure 8 shows a perspective close-up detail cutaway side view of the nozzle assembly of the nebuliser device of figures 4 to 7, showing further detail of the one-way valve, the one-way valve comprising a ball bearing and a crown spring.

[0084] Figure 9a shows a close-up side view of the nozzle assembly of figures 4 to 8, showing further detail of the ball bearing and crown spring of the one-way valve.

[0085] Figure 9b shows a perspective close-up detail cutaway side view of a variation of the nozzle assembly of figures 4 to 8, showing detail of a seal located between the ball bearing and the upper tube housing.

[0086] Figure 10 shows a perspective side view of the crown spring of the embodiment of one-way valve of figures 4 to 9a, the crown spring comprising a circular or ring-shaped base and three spring prongs extending from one side of the base.

[0087] Figure 11 shows a perspective side view of the crown spring of figure 10 from another angle.

[0088] Figure 12 shows a perspective side view of the crown spring of figures 10 and 11 from a third angle.

[0089] Figures 13a and 13b show a cutaway side view and a perspective cutaway view respectively of a nozzle assembly containing a second embodiment of one-way valve, the valve in this embodiment comprising a pressure responsive check valve, the nozzle assembly having a substantially similar structure to that shown in the nebuliser of figures 4 to 8, the second embodiment of valve positioned in substantially the same location as the valve in figures 4 to 8.

[0090] Figures 14a and 14b show a perspective view, and a perspective cutaway view respectively from similar angles, showing detail of the pressure responsive check according to the second embodiment of the invention.

[0091] Figure 15 shows a perspective cutaway side view of a nebuliser device nozzle assembly that contains a third embodiment of valve, the valve in this embodiment comprising a pressure responsive check valve, the nebuliser having a substantially similar structure to that of the nebuliser of figures 4 to 8, the valve positioned in substantially the same location, the valve in this embodiment comprising a flat valve.

[0092] Figure 16 shows a close-up cutaway perspective side view of the nebuliser device nozzle assembly of figure 15 from a similar angle to figure 15.

[0093] Figure 17 shows a perspective side view of the third embodiment of valve, the valve in this embodiment comprising a flat valve that acts as a pressure responsive check valve, the flat valve comprising a flat sealing portion connected to a valve base by three spring members that act to bias the flat sealing portion into a closed position. Figure 18 shows a perspective side view of the third embodiment of valve from a different angle.

[0094] Figure 19 shows a perspective end view of the third embodiment of valve.

[0095] Figure 20 shows a cutaway perspective side view of a nebuliser device nozzle assembly that contains a fourth embodiment of valve, the valve in this embodiment comprising a pressure responsive check valve, the nebuliser having a substantially similar structure to that of the nebuliser of figures 4 to 8, the valve positioned in substantially the same location, the valve in this embodiment comprising a flap valve.

[0096] Figure 21 shows a perspective view of the flap valve of the fourth embodiment of valve as shown in figure 20.

[0097] Figure 22 shows a perspective cutaway side view of a nebuliser device nozzle assembly that contains a fifth embodiment of valve, the valve in this embodiment comprising a pressure responsive check valve, the nebuliser having a substantially similar structure to that of the nebuliser of figures 4 to 8, the valve positioned in substantially the same location, the valve comprising a bullet valve.

[0098] Figure 23 shows a close-up view of the nozzle assembly of figure 22 from the same angle

[0099] Figure 24 shows a perspective side view of the bullet valve of the fifth embodiment.

[0100] DETAILED DESCRIPTION

[0101] Detailed embodiments of the invention will now be described with reference to the figures.

[0102] General

[0103] The valve of the present invention is described below as being used as part of a liquid delivery device - specifically, a nebuliser device. A version of this - nebuliser 1000 - is shown in figures 4 and 5 for the first embodiment of one-way valve, with detail of the first embodiment shown in figures 5 to 12. Substantially similar nebuliser devices are used for the second, third, fourth, and fifth embodiments as shown in figures 13 and 14, figures 15 to 19, figures 20 and 21 , and figures 22 to 24 respectively. Similar numbering will be used to refer to similar elements on all the devices as described below - e.g. nebuliser device 100, 200, 300, upper housing part 101 , 201 , 301 , one-way valve 140, 240, 340 etc, for the first, second and third embodiments respectively. General numbering is used in this section for the general form of nebuliser device.

[0104] The general or stylised form of nozzle assembly 13 and other relevant parts are shown in figure 3 for the purposes of illustration of the general structure. A general form of nebuliser device is shown in figure 4. The general form of nebuliser comprises an upper housing half (generally designated as 11 , but designated as 111 , 211 , etc for specific embodiments) that contains a nozzle assembly 13, and a lower housing half (generally designated as 12, but designated as 112, 212, etc) that in use contains a collapsible reservoir or ‘bag’ (not shown in the figures). A capillary tube 14 extends between the bag and the nozzle assembly 13.

[0105] The nozzle assembly 13 comprises: a nozzle retainer or nozzle holder 15; a nozzle chip / filter 16; a nozzle seal 22; a filter holder 21 and a first filter 20, and; a lower seal 17.

[0106] The elements that form the nozzle assembly are retained with a top nut 18. The nozzle holder 15, nozzle chip / filter 16, lower seal 17, first filter 20, filter holder 21 , and nozzle seal 22 are all enclosed within the top nut 18 once assembled. In use, the top nut 18 screws onto the upper end of an upper tube housing 19 that is located within the upper housing part 11 . The upper tube housing 19 has a passage 23 passing substantially axially therethrough, with a capillary tube 14 passing most of the way through the passage 23 from the base or lower end (that end that is towards the bag), to the upper end where the nozzle assembly 13 is located. The space between the upper end of the capillary tube 14 and the lower end of the first filter 20 forms a metering chamber 24. The one-way valve of the present invention is located in the top end of a passage that runs between the lower end of the first filter 20 and the top end of the capillary tube 14 when the tube 14 is in its lowest position or furthest downwards extent (as described below). That is, the one-way valve is located above (i.e. downstream of), the space that forms the metering chamber 24. In use, the capillary tube 14 moves within the passage towards and away from the nozzle assembly 13 as the nebuliser device is used. For the purposes of this specification, the ‘passage’ should be considered to run between the lower end of first filter 20 and the top or inner end of the capillary tube when it is located at its furthest ‘downwards’ extent - i.e. the position the capillary tube is in when the inhaler is fully cocked and ready to dispense a dose. That is, furthest ‘downwards’ when the inhaler is in the orientation shown in figure 3, which is the orientation for a nebuliser standing upright.

[0107] References to orientations such as ‘upwards’, ‘downwards’ and similar should be taken in this specification as meaning the orientation shown in figure 3 (i.e. the nebuliser stood upright on a horizontal surface such as a table top), even if in use the orientation would differ from this.

[0108] In use, a user rotates the upper and lower parts 11 , 12 relative to one another to pump or prime the device for use. This action causes the capillary tube 14 and bag to move away from the nozzle assembly 13 (that is, downwards towards the base of the nebuliser if it is aligned upright in a similar manner to the prior art nebuliser shown in figure 1) to their lowest position. This lowers the pressure inside metering chamber 24 (the volume of metering chamber 24 is increased without there being a corresponding increase in its contents). This causes liquid from the bag to be sucked up the tube 14 to the upper end, the liquid exiting the upper end of the tube 14 into the metering chamber 24 (that is, before the device is primed, the metering chamber 24 and the bag are at substantially the same internal pressure. When the pressure in the metering chamber decreases, liquid is sucked up the tube 14 from the higher pressure location (the bag) - to the lower pressure region (chamber 24) until enough liquid has flowed to the chamber for the pressure to substantially equalise). This action also compresses a spring 35 within the nebuliser. When a user then triggers the dispensing mechanism (e.g. by pressing a button or similar on the housing of the nebuliser), the tube 14 is forced upwards by the release of compression in the spring 35, and the head of the tube 14 moves rapidly upwards along the passage, forcing liquid out of the metering chamber 24, through the valve, and then through the nozzle assembly 13 as a spray of fine droplets.

[0109] One-Way Valve - First Embodiment

[0110] As shown in figures 5 to 9, the one-way valve 140 of the first embodiment comprises a ball bearing 130 and a crown spring 131 . These are located in a recess formed at the upper end of the passage 123, between the head of the capillary tube 114 and the base or inner end of the first filter 120. The recess is formed so as to be wider than the main part of the passage 123, so that a lip 132 is formed between the recess and the main part of the passage 123.

[0111] The ball bearing 130 is spherical, and has a diameter in the preferred embodiment of 2.5mm. Other diameters can also be used if required - e.g. 2.38mm, 2mm, etc. The ball bearing can be formed from a suitable material such as for example stainless steel or a similarly hard material, although materials with some compliance such as for example elastomers can also be used as minor deformation can help to create a better seal. A spherical ball with a good surface across the entirety of the ball (e.g. no split lines) is suitable, as this has a surface which does not create a leak-path in any orientation.

[0112] As best shown with reference to figure 9a, in a first variation of this embodiment, the inner or lower side of the ball bearing rests against the lip 132. The lip 132 can be shaped so as to conform to the outer surface shape of the ball bearing 130, so as to increase the contact area between the ball bearing 130 and the inner surface of the upper tube housing 119 (the lip 132). The ball bearing forms a blocking member for the one-way valve.

[0113] As best shown in figures 10 to 12, the crown spring 131 comprises a ring-shaped base 131 a, and three spring prongs 131b extending from one or the same side of the base 131a. The ringshaped base forms a main body for the one-way valve, and has a diameter substantially the same as that of the ball bearing 130, which is also substantially the same as that of the recess. The spring prongs 131 b are substantially identical to one another, and are spaced at equal distances around the ring of the ring-shaped base 131a - that is, at 120-degree intervals around the ring. The main body acts to hold and stabilise the one-way valve in position within a passage in a liquid delivery device.

[0114] Each of the spring prongs 131 b is angled inwards slightly so that at their distal ends (that is, the end that in use points downwards or inwards towards the base or bag), the diameter of a circle that covers or connects between the distal ends or tips of the prongs 131b is slightly less than the outer diameter of the ring. The spring prongs act as a biasing member for the valve. The crown spring 131 is a unitary item formed from plastic or similar.

[0115] The upper or outer side of the ball bearing 130 rests on the distal ends of the spring prongs 131 b. These distal ends can be shaped so as to receive the ball bearing - that is, to increase the contact area between the two.

[0116] The outer or upper side of the ring-shaped base 131 a rests against the inner or lower end of the filter holder 121.

[0117] In use, a user rotates the upper and lower parts 111 , 112 of the inhaler relative to one another to pump or prime the device for use as described above for the general form of inhaler, This causes a pressure drop in the metering chamber 124 section of the passage 123, between the upper end of the capillary tube, and the lower end of the ball bearing 130 (the volume of the space increases, while the same amount of fluid / gas is present). As the pressure on the upper side of the ball bearing 130 doesn’t change, this causes a pressure gradient that pushes the ball bearing 130 onto the lip 132, which helps to increase the quality of the seal between the passage 123 and the upper end of the device, above the ball bearing 130. A good / effective seal during this stage of use / operation is highly desirable, as air-ingress through the nozzle past the valve 140 and into the metering chamber 124 causes liquid displacement, and can cause variation in the completeness of filling and subsequent delivered volume of liquid on the next firing stroke - that is, when a user dispenses a dose. Variation on the completeness of filling can cause unacceptable variations in the size of the dose delivered. Further, air ingress reduces the pressure difference between the metering chamber 124 and the bag during the priming action when the inhaler upper and lower parts 111 , 112 are rotated relative to one another to pump or prime the device for use. This increases the time required to prime / f ill the metering chamber 124, and can cause an incomplete or reduced dose to be delivered to the chamber 124 (and then delivered to a user) . Therefore, an effective seal that helps to prevent air ingress is highly desirable. A high-pressure difference / gradient also assists with the collapse of the cartridge reservoir - the reservoir collapses inwards as liquid is drawn out of the reservoir and into the metering chamber 124, and a high pressure gradient assists with this process by helping to overcome the resistance of the reservoir to collapse. It can be seen that a reduction in the pressure difference or pressure gradient caused by air leakage is undesirable. Having a valve in this location such as valve 140 assists with this issue.

[0118] As outlined above, as the capillary tube 114 moves downwards, liquid in the bag is drawn up the capillary tube 114 into the space between the top end of the capillary tube and the lower side of the ball bearing - the metering chamber 124. This re-sets or substantially equalises the pressure in the metering chamber 124. In variations (for this embodiment and the others described below), the capillary tube can be fitted with a capillary valve 1125 that acts in substantially the same manner as the capillary valves of the prior art, and as described above).

[0119] When a user triggers the nebuliser, this dose of liquid is forced past the ball bearing 130, through the first filter 120 and the nozzle chip / filter 116, and out through the nozzle for delivery to a user. This is because the priming action of rotating the two housing halves also causes compression of spring 135. When a user subsequently triggers the nebuliser, the spring 135 partially unloads from this compressed state (reduces compression while retaining a small residual load), and forces the capillary tube 114 upwards at speed, rapidly increasing the pressure in the metering chamber 124. This pressure forces the ball bearing 130 upwards / outwards against the spring prongs 131b, which bend towards the sides of the recess and allow the ball bearing to move upwards / outwards (it can be seen that the travel distance of the ball bearing 130 will be limited by the arms - these will contact the side wall of the recess so that further bending is not possible, and therefore further movement of the ball bearing against the spring action of the prongs 131b is prevented). As the ball bearing has now moved away from the lip 132, the liquid in the metering chamber 124 can now move upwards past the ball bearing, and on through the filter assembly and out of the nebuliser.

[0120] It has been found that having a valve that will open at a very low threshold is advantageous over not using a one-way valve in the passage between the metering chamber and the nozzle assembly as it performs the function of preventing air ingress through the nozzle during priming and closes off the open channel to the environment. However, controlling the opening pressure of the valve has further advantages.

[0121] This action has the further advantage that a certain minimum level of pressure is required in order to initiate movement of the ball bearing 130 against the spring prongs 131 b. The valve is pressed closed - the spring prongs 131b press the ball bearing 130 against the lip 132 - and a certain minimum level of pressure needs to be applied to the underside of the ball bearing in order to overcome the spring force of the spring prongs 131 b and cause the ball bearing to move upwards, away from the lip 132. That is, the valve 140 is acting as a pressure responsive check valve, and will only open to allow flow in one direction once the pressure is at or above a certain threshold level. As outlined in the ‘background’ section above, gradual building of pressure tends to have the effect in use that larger droplets are formed initially, until the pressure reaches full operational force. At full operational force the pressure then provides more desirable small and even-size droplets. The valve arrangement of this embodiment acts to assist with achieving pressure at full operational force as quickly as possible (‘burst pressure’) and to overcome the ‘start-up effect’ of certain already-known types of nebulisers where pressure builds up gradually initially. With the valve held closed until a threshold pressure is reached, this helps to provide a quicker ‘ramp up phase’, and therefore a more consistent droplet size. When the pressure reduces, the valve 140 closes quickly - there is rapid ramp down of delivery pressure (‘ramp clipping’). It should be noted that with hysteresis the level for closing could be different than the threshold opening level. Achieving full operational force as quickly as possible and then rapid ramp down of delivery pressure greatly assists with forming and delivering only or almost entirely only small and evenly-sized droplets. The pressure clipping values will depend on the nozzle geometry and formulation characteristics such as viscosity and surface tension.

[0122] This is especially useful for delivery of lower volumes of medication - ramp up and tail effects are less pronounced and therefore have a smaller impact.

[0123] In a nebuliser with which the present embodiments of valve are intended for use, the usual operating pressure is around 25,000kPa. However, the device is still capable of operating at much lower pressures. Aerosol sprays of reasonable size and droplet consistency will be created with an operating pressure of substantially 4,000kPa (the minimum viable operating pressure), and doses can still be dispensed at pressures lower than this.

[0124] The valve of this embodiment (and the other embodiments described below) can be configured so that it will open at substantially 50% of the minimum viable operating pressure - at a pressure of substantially 2,000kPa for the embodiments described and shown.

[0125] Having a valve that is held closed until a threshold pressure is reached helps to provide a quicker ‘ramp up phase’, even if the threshold pressure is very low (e.g. 2,000kPa as noted above) and limits the delivery of liquid through the nozzle until it has reached sufficient pressure to generate an aerosol spray.

[0126] However, in order to produce a more optimal spray (more optimal size and droplet consistency), the valve (of this embodiment and the others described below) is more usually configured so as to have an opening pressure of substantially 50% of the usual operating pressure - that is, an opening pressure of substantially 12,500kPa and limits the delivery of liquid through the nozzle until it has reached sufficient pressure to generate a more optimal aerosol spray.

[0127] For other types of nozzle, such as for example Rayleigh plate nozzles, the opening pressure can be much lower - the burst pressure for a more open valve solution such as a Rayleigh jet nozzle is any pressure greater than 400kPa. It should be noted that the valve 140 also acts to assist with the prevention of air ingress through the nozzle into the interior of the inhaler, and to assist with the creation of vacuum (that is, pressure lower than atmospheric pressure) during operation. As outlined in the ‘background’ section, the nozzle can create an air leakage path from the exterior of the device to the interior. When the device is pumped or primed, air can be drawn inwards through the nozzle. The air leakage path also provides an open route through the nozzle, and due to open access to the environment this can reduce the shelf-life, stability, and protection of the formulation. The force required to keep the valve closed and sealed against air ingress and to assist with vacuum is not required to be as high as that required to open the valve, and can be very low - for example, substantially around 0.1 kPa.

[0128] The location of the valve of the present invention - above the metering chamber 124, at the top end of the passage that runs between the lower end of the first filter 120 and the top end of the capillary tube 114 - helps to increase the efficiency of the priming or cocking phase of operation. As outlined above, during this phase an area of lower pressure is created in the metering chamber 124 and this causes liquid to be sucked up the tube 114. Having a valve above the metering chamber 124 helps to prevent air from being drawn into the metering chamber 124 through the nozzle during the priming or cocking phase of operation. This drawn-in air would act to decrease the pressure differential between the metering chamber and the bag, and this impacts on the rate and amount of liquid drawn up the capillary tube to the metering chamber.

[0129] The valve 140 is closed during the pumping / priming portion of the usage cycle, and therefore this prevents air or residual liquid from being sucked through the nozzle into the metering chamber.

[0130] Other advantages of the valve of the present invention are outlined below. It should be noted that these advantages also apply to the other embodiments described below.

[0131] In a variation of this embodiment as shown in figure 9b, a seal 117b is located within the inhaler, so that in use this is between the ball bearing 130 and the upper tube housing 119. In use, the ball bearing 130 is pressed onto the upper surface of the seal 117b by the crown spring 131. It should be noted that this seal could be of any suitable shape and size, as long as it locates in use between the one-way valve and the upper tube housing. This arrangement - that is, including a seal - can also be used in the other embodiments as appropriate.

[0132] It can be seen that the valve of this embodiment comprises a particular form of one-way valve, that being a pressure responsive check valve. One-Way Valve - Second Embodiment

[0133] A second embodiment of valve 240 is shown in figures 13a and 13b, 14a and 14b. In figures 13a and 13b, the valve 240 is shown in use located in a nozzle assembly similar to nozzle assembly 13 described above.

[0134] The valve 240 is located at / above the top of passage 223, between the head of the capillary tube 214 and the base or inner end of the nozzle assembly.

[0135] As shown in figures 14a and 14b, the valve 240 comprises a ring-shaped main body 240b, a central sealing portion 240a, and connecting members 240c that connect between the sealing portion 240a and the main body 240b. The valve 240 comprises a unitary member formed from silicone rubber or similar.

[0136] The main body 240b has a flat lower face, and an upper face that has an inwardly-chamfered or curved outer edge, with an outer wall and inner wall that extend upwards substantially perpendicularly to the flat lower face. The main body 240b acts to hold and stabilise the oneway valve in position within a passage in a liquid delivery device, and to create a seal between the metering chamber and the filter holder.

[0137] The central sealing portion 240a comprises a disc-shaped member, circular in plan view, having a thickness approximately half the radius of the disc-shaped member. The upper and lower faces of the disc are substantially flat and parallel to one another.

[0138] The connecting members 240c comprise four pillars that extend in between and connect between the central sealing portion 240a and the main body 240b. The bases of each of the pillars 240c are in the same plane as the lower face of the disc of the central sealing portion 240a, and the flat lower face of the main body 240b. The pillars extend upwards past the upper surfaces of the main body 240b and the central sealing portion 240a, with the upper faces of the pillars all in substantially the same plane. The sides of the pillars are curved to follow the inner curve of the ring-shaped main body 240b, and the outer perimeter of the disc-shaped central sealing portion 240a. The pillars / connecting members 240c act to hold the central sealing portion 240a in position against the open top end of the upper tube housing 219. If upwards pressure is applied to the central sealing portion 240a, the pillars / connecting members 240c deform, and will attempt to return to an undeformed state, pressing the central sealing portion 240a downwards.

[0139] The lower ends of the pillars 240c locate against the top of the upper tube housing 219, and the upper ends of the pillars locate against the underside or upstream side or face of the holder for filter 220 so as to provide sealing pressure between the valve and metering chamber.

[0140] As for the previously-described embodiments, in use a user rotates the upper and lower parts of the inhaler / nebuliser 200 relative to one another to pump or prime the device. This causes a pressure drop in the metering chamber 224 section of the passage, between the upper end of the capillary tube 214 and the lower / inner side of the sealing portion 240a. The sealing portion 240a is pulled or ‘sucked’ against the top of the upper tube housing 219 by the vacuum of the pressure drop, so as to prevent flow from the upper end of the nebuliser through the passage 223, which helps to increase the efficiency of the seal. A good / effective seal during this part of the operation is highly desirable, as outlined in the description of the first embodiment above.

[0141] As the capillary tube 214 moves downwards, liquid in the bag is drawn up the capillary tube 214 into the space between the top end of the capillary tube, and the top end of the passage 223 and the interior of the valve, equalising the pressure.

[0142] When a user triggers the nebuliser, this dose of liquid is forced through the valve 240, the central sealing portion 240a moving upwards so as to allow flow through the valve 240. The connecting members 240c deform to allow the central sealing portion 240a to move away from the top of the upper tube housing 219. That is, the pressure caused by upwards movement of the capillary tube 214 is sufficient to temporarily overcome the force of the connecting members 240c holding the seal in a planar configuration. This allows the liquid in the metering chamber 224 to move upwards through the valve, and on through the filter assembly and out of the nebuliser.

[0143] The valve 240 in this embodiment has substantially the same advantages as outlined above for the first embodiment. The valve 240 is acting as a pressure responsive check valve, and will only open to allow flow in one direction once the pressure difference across the valve is at or above a certain threshold level. This is achieved in the configuration described above as the connecting members 240c are sufficiently thick and bulky to resist the initial pressure increase, and will then deform once the pressure has reached a threshold level.

[0144] The valve 240 also acts to assist with the prevention of air ingress through the nozzle into the interior of the inhaler through the nozzle, and to assist with the creation of vacuum during operation in a similar manner to that outlined above for the first embodiment.

[0145] It can be seen that the valve of this embodiment comprises a particular form of one-way valve, that being a pressure responsive check valve.

[0146] One-Way Valve- Third Embodiment

[0147] As shown in figures 15 to 19, the valve of the third embodiment comprises a flat valve 340.

[0148] The flat valve 340 is located at / above the top of passage 323, between the head of the capillary tube 314 and the base or inner end of the nozzle assembly 313. The flat valve comprises a flat sealing portion 340a, a ring-shaped main body 340b, and three curved spring members 340c that connect between the sealing portion 340a and the main body 340b, the three curved spring members 340c acting in use to bias the flat sealing portion 340a into a closed position. That is, they act as a biasing mechanism for the one-way valve.

[0149] As shown in figures 15 and 16, a recess is formed in the top end of the upper tube housing 319. The ring-shaped main body 340b of the flat valve locates into the recess in use, and spans the full height of the recess, and contacts the side wall of the recess around the perimeter of the side wall of the recess. The main body acts to hold and stabilise the one-way valve in position within a passage in a liquid delivery device. The valve 340 comprises a unitary member formed from silicone rubber or similar.

[0150] The three curved spring members 340c extend inwards and downwards from the top end of the main body 340b, to the sealing portion 340a.

[0151] The sealing portion 340a locates over the top end of the upper tube housing 319 to seal the upper tube housing 319 - that is, to act as a blocking member. In this embodiment, the inner / lower side edge of the sealing portion 340a and the top end of the upper tube housing 319 are mutually chamfered to increase the contact surface area and therefore the effectiveness of the seal. The top of the upper tube housing 319 forms a lip 332.

[0152] As for the previously-described embodiments, in use a user rotates the upper and lower parts of the nebuliser, within which the third embodiment of one-way valve is fitted, relative to one another to pump or prime the device. This causes a pressure drop in the metering chamber 324, between the upper end of the capillary tube, and the lower / inner side of the sealing portion 340a. The sealing portion 340a seals against the top end of the upper tube housing 319 to prevent flow from the upper end of the nebuliser through the passage 323, and so as the capillary tube moves the volume of the space increases while the same amount of fluid / gas is present, causing a pressure drop that acts to ‘suck’ the sealing portion 340a onto the top end of the passage. A good / effective seal during this part of the operation is highly desirable, as outlined above for the first embodiment.

[0153] As the capillary tube 314 moves downwards, liquid in the bag is drawn up the capillary tube 314 into the space between the top end of the capillary tube, and the top end of the passage 323 and the interior of the valve, equalising the pressure.

[0154] When a user triggers the nebuliser, this dose of liquid is forced through the valve 340, through the first filter 320 and the nozzle chip / filter 316, and out through the nozzle for delivery to a user. This is because the priming action of rotating the two housing halves also causes compression of a spring. When a user triggers the nebuliser, the spring partially unloads from this compressed state (reduces compression while retaining a residual load of approximately 35N), so as to force the capillary tube 314 upwards at speed, rapidly increasing the pressure in the metering chamber 324 and forcing the sealing portion 340a upwards to open - that is, the pressure caused by movement of the capillary tube 314 is sufficient to overcome the force exerted by the three curved spring members 340c. This allows the liquid in the metering chamber 324 to move upwards through the valve, and on through the filter assembly and out of the nebuliser.

[0155] The valve 340 in this embodiment has substantially the same advantages as outlined above for the first and second embodiments. The valve 340 is acting as a pressure responsive check valve, and will only open to allow flow in one direction once the pressure difference across the valve is at or above a certain threshold level. The valve 340 also acts to assist with the prevention of air ingress through the nozzle into the interior of the inhaler, and to assist with the creation of vacuum during operation in a similar manner to that outlined above for the first and second embodiments.

[0156] It can be seen that the valve of this embodiment comprises a particular form of one-way valve, that being a pressure responsive check valve.

[0157] One-Way Valve - Fourth Embodiment

[0158] As shown in figures 20 and 21 , the one-way valve of the fourth embodiment comprises a flap valve 440.

[0159] The flap valve 440 is located at / above the top of passage 423, between the head of the capillary tube 414 and the base or inner end of the nozzle assembly.

[0160] As shown in figure 21 , the flap valve 440 is planar, and comprises a flat sealing portion 440a, a ring-shaped main body 440b, and two connecting members 440c that connect between the sealing portion 440a and the main body 440b. The main body acts to hold and stabilise the one-way valve in position within a passage in a liquid delivery device. The planar nature of the flap valve 440 means that the connecting members 440c act in use to bias the flat sealing portion 440a towards the plane of the flap valve.

[0161] In use, the flap valve 440 is located within the housing so that it is planer when no ‘usage’ forces are acting on the valve. The sealing portion 440a is located so that the sealing portion extends across the top of the passage 423, to seal the passage.

[0162] The planar nature of the flap valve 440 means that the connecting members 440c act in use to bias the flat sealing portion 440a towards the plane of the flap valve.

[0163] In use, the flap valve 440 is located within the housing so that when no ‘usage’ forces are acting on the valve, the sealing portion 440a extends across the top of the upper tube housing 419, to seal the upper tube housing 419.

[0164] As for the previously-described embodiments, in use a user rotates the upper and lower parts relative to one another to pump or prime the device. This causes a pressure drop in the metering chamber 424 section of the passage, between the upper end of the capillary tube, and the lower / inner side of the sealing portion 440a. The sealing portion 440a is pulled or ‘sucked’ against the top of the upper tube housing 419 by the vacuum of the pressure drop, so as to prevent flow from the upper end of the nebuliser through the passage 423, which helps to increase the efficiency of the seal. A good / effective seal during this part of the operation is highly desirable, as outlined above for the previously-described embodiments.

[0165] As the capillary tube 414 moves downwards, liquid in the bag is drawn up the capillary tube 414 into the space between the top end of the capillary tube, and the top end of the passage 423 and the interior of the valve, equalising the pressure.

[0166] When a user triggers the nebuliser, this dose of liquid is forced through the valve 440, the sealing portion 440a moving upwards with the connecting members 440c deforming to allow this - that is, the pressure caused by upwards movement of the capillary tube 414 is sufficient to temporarily overcome the spring force holding the sealing portion 440a against the top of the upper tube housing 419. This allows the liquid in the metering chamber 424 to move upwards through the valve, and on through the filter assembly and out of the nebuliser.

[0167] The valve 440 in this embodiment has substantially the same advantages as outlined for the embodiments above. The valve 440 is acting as a pressure responsive check valve, and will only open to allow flow in one direction once the pressure difference across the valve is at or above a certain threshold level. The valve 440 also acts to assist with the prevention of air ingress through the nozzle into the interior of the inhaler, and to assist with the creation of vacuum during operation in a similar manner to that outlined for the embodiments above.

[0168] One-Way Valve - Fifth Embodiment

[0169] As shown in figures 22 to 24, the one-way valve of the fifth embodiment comprises a bullet valve 540.

[0170] As shown in the figures, the bullet valve is in use located in a recess formed in the passage 523, at the upper end of the passage, between the head of the capillary tube 514 and the base or inner end of the nozzle assembly 513. The recess is formed so as to be wider than the main part of the passage 523, so that a lip 532 is formed between the recess and the main part of the passage 523. The bullet valve 540 is a unitary item that comprises a dome-shaped or hemispherical blocking head 530 and spring legs 531 that have the form of castellations extending from the flat or bottom side of the blocking head 530. The legs 531 in this embodiment form both the main body and biasing mechanism of the one-way valve. When the inhaler / nebuliser is used (fired) to dispense a dose, the bullet valve acts as a blocking member for the one-way valve, and will elastically deform slightly, and then return to an undeformed state. In order to achieve this, the bullet valve is formed from a suitable material. Examples of suitable materials would be elastomeric materials such as silicone rubber, or a thermoplastic elastomer (TPE),. The blocking head 530 forms a blocking member, and has a diameter in the preferred embodiment of 2.5mm. Other diameters can also be used if required - e.g. 2.38mm, 2mm. The spring legs 531 are angled slightly outwards from one another so that they ‘spread’ away from one another as they extend from the bottom or flat side of the blocking head 530 (that side that faces ‘upwards’). The outer ends of the legs - that end away from the flat or bottom side of the blocking head 530 - are wider / thicker at substantially the last outer third of the leg than the inner two-thirds between the flat or bottom side of the blocking head 530 and the wider leg outer end, with a step formed on the outside of the leg between the last outer third of the leg and the inner two-thirds.

[0171] In use, the domed or curved side of the blocking head 530 rests against the lip 532. The lip 532 can be shaped so as to conform to the outer surface shape of the blocking head 530, so as to increase the contact area between the blocking head 530 and the inner surface of the upper tube housing 519 (the lip 532). It should be noted that the blocking head could be profiled as any other suitable shape other than domed - for example, the blocking head could be a conical shape, or bullet-shaped, or could have a flatter profile.

[0172] As shown in figure 24, the spring legs 531 have a curved outer profile that curves in the same direction as the perimeter of the flat side of the blocking head 530, so that the curve(s) of the legs conform to the circular cross-sectional shape of the recess, with the legs fitting snugly within the recess with the outer curved profile resting against the edge / end of the recess so that in use, the outer or free ends of the legs 531 are in effect anchored against the inner or lower end of the filter holder 521 .

[0173] In use, a user rotates the upper and lower parts of the inhaler device relative to one another to pump or prime the device for use as described above for the general form of inhaler, and for the previous embodiments. This causes a pressure drop in the metering chamber 524, between the upper end of the capillary tube, and the lower or outer end of the blocking head 530 (the volume of the space increases, while the same amount of fluid / gas is present). As the pressure on the upper side of the blocking head 530 doesn’t change, this causes a pressure gradient that pushes the blocking head 530 onto the lip 532, which helps to increase the quality of the seal between the passage 523 and the upper end of the device, above the blocking head 530. A good / effective seal during this part of the operation is highly desirable, as outlined for the embodiments above.

[0174] In the same or similar manner to that outlined above, as the capillary tube 514 moves downwards, liquid in the bag is drawn up the capillary tube 514 into the space between the top end of the capillary tube and the blocking head 530 - the metering chamber 524. This re-sets or substantially equalises the pressure in the chamber 524. When a user subsequently triggers the inhaler device, this dose of liquid is forced past the blocking head 530, through the first filter 520 and the nozzle chip / filter 516, and out through the nozzle for delivery to a user.

[0175] This is because the priming action of rotating the two housing halves also causes compression of a spring. When a user triggers the nebuliser, the spring partially unloads from this compressed state (reduces compression while retaining a residual load of approximately 35N), and forces the capillary tube 514 upwards at speed, rapidly increasing the pressure in the metering chamber 524. This pressure forces the blocking head 530 upwards against the legs 531 . As noted above, the free ends of the legs 531 are anchored against the inner or lower end of the filter holder 521 . Both the legs 531 and the blocking head 530 will deform and compress to allow the blocking head 530 to move upwards. As the blocking head 530 has now moved away from the lip 532, the liquid in the metering chamber 524 can now move upwards past the blocking head, and on through the filter assembly and out of the nebuliser.

[0176] This action has the further advantage that a certain minimum level of pressure is required in order to initiate movement of the blocking head 530. The valve is pressed closed by the elastic nature of the legs 531 pressing the blocking head 530 against the lip 532, and a certain minimum level of pressure needs to be applied to the underside of the blocking head 530 in order to overcome the spring force of the legs 531 and cause the blocking head 530 to move upwards away from the lip 532. This helps to overcome the ‘start-up effect’ of certain previous forms of nebulisers where pressure builds up gradually initially.

[0177] The valve in this embodiment has substantially the same advantages as outlined for the previous embodiments above. The valve is acting as a pressure responsive check valve, and will only open to allow flow in one direction once the pressure difference across the valve is at or above a certain threshold level. The valve also acts to assist with the prevention of air ingress through the nozzle into the interior of the inhaler, and to assist with the creation of vacuum during operation in a similar manner to that outlined above.

[0178] It can be seen that the valve of this embodiment comprises a particular form of one-way valve, that being a pressure responsive check valve.

[0179] In the embodiments above, the one-way valves are described as being used with a SMI that uses a bag as a medicament reservoir. It should be noted that other types of device, with other types of reservoir, could also be used, such as for example a syringe style cartridge.

[0180] As well as the advantages outlined above - that the valve is closed during the priming phase of operation, and open during firing or dispensing, which assists with preventing air ingress, and the valve requires a certain minimum level of activation pressure - the use of a one-way valve as for example in the embodiments described above for the present invention also helps to ensure that a correct dosage is administered each time the device is used, and that substantially all or most of the medicament in the reservoir can be used. The use of a one-way valve also helps to shut off the open route to the air, thus preventing air ingress through that route during priming, but also during storage / at rest. It also prevents or reduces seepage of liquid out through the nozzle when not in use / storage.

[0181] A further advantage of the invention is that the valve creates a seal that closes off the pathway from the top or exit of the capillary tube, to the exit of the nozzle assembly (the external environment). This has the advantage that the liquid reservoir and the capillary tube are closed off from the external environment, and evaporation of the contents of the inhaler from the nozzle is significantly reduced. Further to this, the longer-term stability performance of the inhaler is enhanced, as the valve helps to prevent the contents of the device from contact with air, and oxidation.

[0182] Locating the valve outside the capillary tube also assists with overcoming capillary effects that can still be present even if a one-way valve is present but is located in the capillary tube (and which can lead to deposits of non-volatile residues at the nozzle exit), and allows more effective valves to be used.

Claims

CLAIMS1. A liquid delivery device, comprising: a lower housing part configured to contain a collapsible reservoir; an upper housing part configured to contain a nozzle assembly and metering chamber, the metering chamber located at or towards the inner or upstream end of the nozzle assembly, the nozzle assembly configured to convert liquid received from the metering chamber to a droplet spray at the outer or downstream end for delivery to a user; a passage extending between the collapsible reservoir and the metering chamber to in use deliver liquid from the collapsible reservoir to the metering chamber; characterised in that a one-way valve is located in the passage between the metering chamber and the nozzle assembly, the one-way valve configured to open to allow liquid to pass from the metering chamber to the nozzle assembly, the valve in the closed position substantially blocking the passage to prevent the flow of gases and fluids into the collapsible reservoir.

2. A liquid delivery device as claimed in claim 1 wherein the one-way valve comprises a pressure responsive check valve.

3. A liquid delivery device as claimed in claim 1 wherein the one-way valve is configured to have an opening pressure of substantially 0.1 kPa.

4. A liquid delivery device as claimed in claim 1 or claim 2 wherein the one-way valve is configured to have a minimum opening pressure of substantially 50% of the minimum viable operating pressure of the liquid delivery device.

5. A liquid delivery device as claimed in claim 1 or claim 2 wherein the one-way valve is configured to have a minimum opening pressure of substantially 50% of the usual operating pressure of the liquid delivery device.

6. A liquid delivery device as claimed in claim 1 or claim 2 wherein the one-way valve is configured to have an opening pressure of substantially 400kPa.

7. A liquid delivery device as claimed in claim 1 or claim 2 wherein the one-way valve is configured to have an opening pressure of substantially 1 ,000kPa.

8. A liquid delivery device as claimed in claim 1 or claim 2 wherein the one-way valve is configured to have an opening pressure of substantially 4,000kPa.

9. A liquid delivery device as claimed in any one of claims 1 to 8 wherein the one-way valve comprises:a main body configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage; a blocking member configured to move within the passage from a first position where fluid flow through the passage is substantially blocked, to a second position where fluid can flow through the passage; a biasing mechanism configured to extend between the main body and the blocking member to bias the blocking member towards the first position.

10. A liquid delivery device as claimed in claim 9 wherein the main body is ring-shaped.11 . A liquid delivery device as claimed in claim 9 or claim 10 wherein the blocking member comprises a ball bearing.

12. A liquid delivery device as claimed in any one of claims 9 to 11 wherein the biasing mechanism comprises a plurality of spring prongs.

13. A liquid delivery device as claimed in claim 12 wherein the spring progs are spaced at substantially equal intervals from one another.

14. A liquid delivery device as claimed in claim 12 or claim 13 wherein the biasing mechanism comprises three spring prongs.

15. A liquid delivery device as claimed in any one of claims 12 to 14 wherein the spring prongs are angled inwards.

16. A liquid delivery device as claimed in any one of claims 12 to 15 wherein the blocking member ends of the spring prongs are shaped to receive the blocking member.

17. A liquid delivery device as claimed in any one of claims 9 to 16 wherein the blocking member comprises a flat sealing portion.

18. A liquid delivery device as claimed in claim 17 wherein the flat sealing portion has a chamfered edge.

19. A liquid delivery device as claimed in claim 17 or claim 18 wherein the spring mechanism comprises a plurality of spring members integrally formed with and extending from the main body.

20. A liquid delivery device as claimed in claim 19 wherein the spring members are spaced at substantially equal intervals from one another.21 . A liquid delivery device as claimed in claim 19 or claim 20 wherein the biasing mechanism comprises three members.

22. A liquid delivery device as claimed in any one of claims 17 to 21 wherein the flat sealing portion and spring mechanism are integrally formed with the main body so that the one-way valve comprises a unitary item.

23. A liquid delivery device as claimed in any one of claims 1 to 8 wherein the one-way valve comprises a flap valve.

24. A liquid delivery device as claimed in any one of claims 1 to 8 wherein the one-way valve comprises: a blocking head configured to locate within the nebuliser passage so as to be movable between a first position where fluid flow through the passage is substantially blocked, and a second position where fluid can flow through the passage; a plurality of spring legs configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage, and to bias the blocking member towards the first position.

25. A one-way valve for a liquid delivery device as claimed in claim 24 wherein the blocking head is dome-shaped.

26. A one-way valve for a liquid delivery device as claimed in claim 24 wherein the blocking head has a conical shape.

27. A one-way valve for a liquid delivery device as claimed in claim 24 wherein the blocking head is bullet-shaped.

28. A liquid delivery device as claimed in any one of claims 24 to 27 wherein the spring legs have the form of castellations extending from the bottom side of the blocking head.

29. A liquid delivery device as claimed in any one of claims 24 to 28 wherein the spring legs are angled away from one another.

30. A liquid delivery device as claimed in any one of claims 24 to 29 wherein the spring legs are spaced at substantially equal intervals from one another.31 . A liquid delivery device as claimed in any one of claims 24 to 30 wherein the one-way valve comprises four spring legs.

32. A liquid delivery device as claimed in any one of claims 24 to 31 wherein the outer or free ends of the legs are thicker than the inner portion of the legs.

33. A liquid delivery device as claimed in any one of claims 24 to 32 wherein the spring legs have a curved outer profile so that the curve of the legs conforms to the cross-sectional shape of the recess.

34. A liquid delivery device as claimed in any one of claims 24 to 33 wherein the blocking head has a diameter of substantially 2.5mm.

35. A liquid delivery device as claimed in claim 9 or claim 10 wherein the main body comprises a flat lower face, and an upper face that has an inwardly-chamfered or curved outer edge, with an outer wall and inner wall that extend upwards substantially perpendicularly to the flat lower face.

36. A liquid delivery device as claimed in claim 9 or claim 10 wherein the blocking member comprises a disc-shaped member having a thickness substantially half that of the radius of the disc-shaped member, the upper and lower faces of the disc substantially flat and substantially parallel to one another.

37. A liquid delivery device as claimed in claim 9 or claim 10 wherein the biasing member comprises a plurality of pillars that extend and connect between the central sealing portion and the main body, the pillars extending upwards past the upper surfaces of the main body.

38. A liquid delivery device as claimed in any one of claims 35 to 37 wherein the blocking member and biasing member are integrally formed with the main body so that the one-way valve comprises a unitary item.

39. A one-way valve for a liquid delivery device, comprising: a main body configured to locate within a passage within the liquid delivery device; a blocking member configured to move within the passage from a first position where fluid flow through the passage is substantially blocked, to a second position where fluid can flow through the passage; a biasing mechanism configured to extend between the main body and the blocking member to bias the blocking member towards the first position.

40. A one-way valve as claimed in claim 39 wherein the main body is ring-shaped.41 . A one-way valve as claimed in claim 39 or claim 40 wherein the blocking member comprises a ball bearing.

42. A one-way valve as claimed in any one of claims 39 to 41 wherein the biasing mechanism comprises a spring mechanism comprising plurality of spring prongs.

43. A one-way valve as claimed in claim 42 wherein the spring prongs are angled inwards.

44. A one-way valve as claimed in claim 42 or claim 43 wherein the blocking member ends of the spring prongs are shaped to receive the blocking member.

45. A liquid delivery device as claimed in claim 44 wherein the blocking member comprises a flat sealing portion.

46. A one-way valve as claimed in claim 45 wherein the flat sealing portion comprises a chamfered edge.

47. A one-way valve as claimed in claim 45 or claim 46 wherein the spring mechanism comprises a plurality of spring members integrally formed with and extending from the main body.

48. A one-way valve as claimed in any one of claims 45 to 47 wherein the flat sealing portion and spring mechanism are integrally formed with the main body so that the one-way valve comprises a unitary item.

49. A one-way valve for a liquid delivery device, comprising: a blocking head configured to locate within a passage within the liquid delivery device so as to be movable between a first position where fluid flow through the passage is substantially blocked, and a second position where fluid can flow through the passage; a plurality of spring legs configured to locate within and extend across the passage so as to hold and stabilise the one-way valve in position within the passage, and to bias the blocking member towards the first position.

50. A one-way valve for a liquid delivery device as claimed in claim 49 wherein the blocking head is dome-shaped.51 . A one-way valve for a liquid delivery device as claimed in claim 49 wherein the blocking head has a conical shape.

52. A one-way valve for a liquid delivery device as claimed in claim 49 wherein the blocking head is bullet-shaped.

53. A liquid delivery device as claimed in any one of claims 49 to 52 wherein the spring legs have the form of castellations extending from the bottom side of the blocking head.

54. A liquid delivery device as claimed in any one of claims 49 to 53 wherein the spring legs are angled away from one another.

55. A liquid delivery device as claimed in any one of claims 49 to 54 wherein the spring legs are spaced at substantially equal intervals from one another.

56. A liquid delivery device as claimed in any one of claims 49 to 55 wherein the one-way valve comprises four spring legs.

57. A liquid delivery device as claimed in any one of claims 49 to 56 wherein the outer or free ends of the legs are thicker than the inner portion of the legs.

58. A liquid delivery device as claimed in any one of claims 49 to 57 wherein the spring legs have a curved outer profile so that the curve of the legs conforms to the cross-sectional shape of the recess.

59. A liquid delivery device as claimed in any one of claims 49 to 58 wherein the blocking head has a diameter of substantially 2.5mm.

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