Metered dose device

Abstract

A discharge assembly is provided for discharging a metered volume of liquid in a pressurized or pressurizable container, the assembly comprising: (v) a housing having a liquid inlet at a first end, (vi) a valve stem having a body within the housing and having a head portion projecting from a second end of the housing, the valve stem is axially movable relative to the housing between a first extreme position, in which the assembly is closed to the liquid discharge, and a second extreme position, in which the metering volume is discharged, (vii) a chamber disposed within the valve stem body, the valve stem has a chamber, and has a liquid inlet toward a first end of the chamber and a first fluid transfer passage toward an opposite second end of the chamber, the first fluid transfer passage providing communication between the chamber and an exterior of the valve stem, and (viii) a liquid discharge element, and a liquid discharge element movable along said chamber from a liquid filling position to a liquid discharge position to effect discharge of a metered volume of liquid, in which the exterior of the valve stem and the interior of the housing are configured such that: (c) in a first limit position of the valve stem, the liquid discharge element is movable from a liquid filling position to a liquid discharge position; a second fluid transfer passage is present along the outside of the stem between the inlet of the housing and the first fluid transfer passage, and (d) in a second limit position of the stem, the fins form a temporary interference seal between the interior of the housing and the exterior of the stem, thereby closing the second fluid transfer passage to prevent fluid flow.

Description

Technical Field

[0001] The present invention relates to a liquid dispensing device for dispensing a metered volume of a liquid. The present invention relates more particularly (but not necessarily exclusively) to such a device in the form of an aerosol dispensing device. Background Art

[0002] There are currently two methods for achieving self-delivery of liquid in an aerosol, namely: (i) propulsion by means of a gas dissolved under pressure into a liquid solution; (ii) providing a substantially insoluble compressed gas within the aerosol container. Aerosol devices using dissolved gas propellants (e.g., liquid natural gas such as butane) rely on the flashing of the dissolved gas from the solution due to the pressure drop that occurs when diffusing from the pressurized aerosol container into the atmosphere. Alternatively, propulsion can be provided by an insoluble compressed gas (e.g., nitrogen, carbon dioxide, or air) that is used to eject the liquid from the body of the aerosol container.

[0003] Many medical, air freshener, insecticide and disinfectant aerosol applications require the delivery of a metered amount of aerosol from an aerosol container, and metered aerosol valves have been disclosed in connection with both of these propulsion methods.

[0004] In the case of dissolved gas propellants, a metered amount of a propellant liquid solution may be received from the body of the aerosol container into a metering chamber during the charging phase and then released into the atmosphere during the discharge phase, with evaporation of the dissolved gas (known as "flash") driving the metered amount out of the metering chamber and into the atmosphere. The dissolved propellant used in such aerosol devices is typically butane, the release of which into the atmosphere has adverse environmental and cost impacts, as well as creating a fire safety risk. Avoiding the use of such volatile propellants has significant environmental implications.

[0005] Since the delivery liquid is relatively incompressible, the metered dose of the delivery liquid will not automatically eject from the metering chamber. Therefore, several methods have been used to drive the necessary ejection.

[0006] In one approach, an aerosol valve is designed to discharge a certain amount of compressed gas from an aerosol container into a metering chamber, and then expel the accompanying liquid out of the metering chamber during discharge. Such a device is described in US 3394851. However, such a device depletes the gas pressure within the aerosol container and therefore requires a high gas-to-liquid ratio, which affects manufacturing costs.

[0007] An alternative approach is to use an elastomeric membrane as part of the metering chamber which expands during metering chamber refill and then forces the liquid contents from the metering chamber back into the chamber during the discharge phase, thereby driving the liquid contents out of the metering chamber. Another related approach is known to use an elastic bellows. Such devices are described in US4953759, US5037013 and WO9511841. Metering valves using such elastic walls are susceptible to performance variations due to material variations of the elastic wall, associated impacts on manufacturing yields, and are susceptible to performance degradation during service life due to degradation of the elastic wall material.

[0008] An improved assembly for discharging a metered volume of liquid is disclosed in European patent EP2485966, the contents of which are incorporated herein by reference. However, the assembly disclosed in this document also has disadvantages, particularly in terms of the ease of manufacture of the valve and its applicability in an automatic discharge system.

[0009] It would be advantageous to provide an assembly for discharging a metered volume of a liquid that addresses some or all of the above-mentioned disadvantages. Summary of the invention

[0010] According to a first aspect of the present invention, as set forth in claim 1, there is disclosed a discharge assembly for discharging a metered volume of liquid from a pressurized or pressurizable container.

[0011] Emission components may include:

[0012] (i) a housing having a liquid inlet at a first end thereof,

[0013] (ii) a valve stem having a body located within the housing and having a head portion projecting from a second end of the housing, the valve stem being axially movable relative to the housing between a first extreme position in which the assembly is closed to discharge of liquid and a second extreme position in which a metered volume is discharged,

[0014] (iii) a chamber disposed within the body of the valve stem, the chamber having a liquid inlet toward a first end of the chamber and a first fluid transfer passage toward an opposite second end of the chamber, the first fluid transfer passage providing communication between the chamber and an exterior of the valve stem, and

[0015] (iv) a liquid discharge element movable along the chamber from a liquid filling position to a liquid discharge position to effect discharge of a metered volume of liquid,

[0016] Wherein, the exterior of the valve stem and the interior of the housing are configured such that:

[0017] (a) in a first extreme position of the valve stem, a second fluid transfer passage exists along the exterior of the valve stem between the inlet of the housing and the first fluid transfer passage, and

[0018] (b) At the second extreme position of the valve stem, the fin forms a temporary interference seal between the interior of the housing and the exterior of the valve stem, thereby closing the second fluid transmission passage to prevent fluid flow.

[0019] Such an exhaust assembly provides various advantages over prior art exhaust assemblies. In particular, the improved exhaust assembly is easier to manufacture, provides a more reliable sealing and actuation mechanism, allows for longer stroke lengths, uses less material, has a lower failure rate during manufacturing due to reduced deformation, and reduces the chance of molded pins getting stuck during manufacturing. Ultimately, these advantages combine to provide a significantly improved exhaust assembly with lower manufacturing cycle time and improved performance.

[0020] Optionally, the fins are arranged inside the housing. Optionally, the fins are formed integrally with the interior of the housing. This makes manufacturing easier, as described more fully below.

[0021] Optionally, the assembly includes a seat configured to connect with the fin to provide an interference seal when the valve stem is in the second extreme position. This allows for improved sealing in the second extreme position, thereby reducing the chance of failure of the exhaust assembly, as described more fully below.

[0022] Optionally, the seat comprises a chamfered surface. This can improve the seal to the fin. Optionally, the fin extends at least 0.1 mm into the path of the seat, preferably between 0.1 mm and 0.2 mm (inclusive). This ensures that the fin and the valve portion form a good seal during actuation.

[0023] Optionally, the length of the temporary interference seal is between 0.2 mm and 3 mm, preferably between 1 mm and 2 mm. This provides a strong seal, reduces the chance of leakage, and allows longer stroke lengths, as described fully below.

[0024] Optionally, the housing comprises a top housing portion and a bottom housing portion. This makes manufacturing easier and reduces stress on the lower portion and walls of the housing. In particular, the base of the housing needs to support fewer components. Therefore, the base portion can be made thinner, making manufacturing faster and more reliable, as described more fully below.

[0025] Optionally, the top housing portion is configured to attach to a mounting cup. This means that the discharge assembly can be attached to any container.

[0026] Optionally, the top housing part and the bottom housing part are joined by a permanent interference fit. This provides a simple and strong mechanical connection that can withstand the forces applied during actuation and refilling. Preferably, the permanent interference fit is configured to withstand an applied force of 100N, such as may be generated during actuation of an automatic discharge device (such as an automatic air freshener) or during refilling.

[0027] Optionally, the bottom housing portion includes a channel configured to receive the top housing portion. Optionally, the channel includes a recess configured to receive a corresponding protrusion on the top housing portion and / or the channel includes a protrusion configured to interface with a corresponding recess of the top housing portion. This provides a simple and easily formed mechanism for providing a permanent interference fit between the housing portions.

[0028] Optionally, the bottom housing portion comprises a base portion having a thickness of no more than 2 mm. This facilitates rapid and reliable manufacturing while reducing the risk of deformation, as described more fully below.

[0029] Optionally, the discharge assembly has a stroke length of at least 2 mm. This allows the discharge assembly to be used in a range of applications, including automatic discharge assemblies, such as automatic air fresheners, which typically require a minimum stroke length of 2 mm to work reliably. This will be described more fully below.

[0030] Optionally, at least one of the following volumes is tapered: one or more chambers disposed within the valve stem body; the internal volume of the top housing portion; the internal volume of the bottom housing portion; and the first fluid transfer channel. The tapered volumes mean that the forming pins can be more easily removed during manufacturing, as described more fully below.

[0031] Optionally, when in the liquid discharge position, the liquid discharge element abuts a sealing surface disposed within the valve stem chamber. It will be appreciated that ensuring a good seal of this surface is very important, as fluid leakage around the ball will cause the discharge assembly to spray a constant stream of fluid rather than a metered dose. The inventors have identified a variety of mechanisms for improving the sealing of the liquid discharge element to the sealing surface to avoid this situation.

[0032] In one example, the sealing surface may include an O-ring or a gasket, preferably an O-ring or a gasket made of a thermoplastic material or rubber. The O-ring or the gasket may create a better seal to the liquid discharge element than a simple sealing surface without such an O-ring or a gasket.

[0033] Nevertheless, inserting an O-ring or gasket into the valve stem during manufacturing may increase manufacturing and cycle time. Therefore, in some embodiments, the liquid sealing surface is chamfered at an angle relative to the longitudinal axis of the valve stem. This provides a more robust seal, reduces the chance of failure, and is easier to manufacture, as described more fully below. Such a sealing surface provides similar benefits to inserting an O-ring or gasket, but without the added complexity during assembly. Preferably, the angle created by the chamfered sealing surface is between 120 and 180 degrees, more preferably between 120 and 160 degrees. These angles provide a particularly robust seal during actuation.

[0034] Alternatively, the sealing surface may have a curved profile, preferably a convex curved profile, such that the sealing surface protrudes into the valve stem interior and into the path of the liquid discharge element. Alternatively, the sealing surface may have a concave curved profile such that the sealing surface is configured to receive the liquid discharge element within the concave profile.

[0035] Sealing surfaces having curved profiles may provide similar benefits as chamfered sealing surfaces, particularly improved sealing without the need for intervening o-rings or gaskets. In fact, the inventors have discovered that curved profiles may provide a more reliable seal than simple flat chamfered surfaces because the curved profiles are less susceptible to deformation during manufacturing due to "ovality" effects, which may cause flat surfaces to twist and bend during cooling, as described more fully below.

[0036] Preferably, when the sealing surface has a convexly curved profile, its radius is between 1.5 mm and 1.8 mm, measured from its centre point of curvature at its maximum curvature. The inventors have recognised that this radius range provides a particularly good seal for a convex surface.

[0037] Preferably, where the sealing surface has a concave curved profile, the lowermost surface of the sealing surface defines an angle between 20 and 40 degrees within which the liquid discharge element is accommodated. More preferably, the angle is between 25 and 35 degrees, and more preferably the angle is about 30 degrees. The inventors have identified that this range of angles provides a particularly good seal for concave surfaces.

[0038] Optionally, the liquid discharge element can be moved from its liquid discharge position to its liquid filling position by a return force, wherein the liquid discharge element optionally has negative buoyancy in the liquid to be dispensed to provide at least part of said return force. This ensures that the discharge element reliably returns to its liquid filling position after actuation.

[0039] Optionally, the liquid discharge element consists of at least one of the following group: metal, such as stainless steel; and synthetic polymer material. These materials are strong and therefore wear minimally.

[0040] In a preferred embodiment, the liquid discharge element consists of a thermoplastic elastomer, more preferably a vulcanized thermoplastic rubber, The inventors have identified that these materials produce a particularly good seal between the liquid discharge element and the sealing surface in the valve stem.

[0041] Preferably, the liquid discharge element has a Shore hardness of 40 to 70, measured in Shore D durometer. This ensures robustness while still allowing a good seal.

[0042] Preferably, the liquid discharge element weighs at least 0.03 g in order to ensure that the liquid discharge element reliably sinks under the effect of gravity after discharging a metered volume.

[0043] Optionally, the liquid discharge element is spherical. A particular advantage of a sphere is that an adequate seal is formed between the liquid discharge element and the metering chamber, but the friction between the metering chamber wall and the sphere is minimized, so that the sphere moves more freely than, for example, a cylindrical piston. Furthermore, the manufacturing tolerances of a cylindrical piston are more demanding than for a sphere, since the sphere can roll and rotate more freely in the cavity than the former.

[0044] Optionally, a head portion of the valve stem protruding from the second end of the housing can move in an annular seal arranged at the second end of the housing, and the head portion has a third fluid transmission channel connected to the outlet of the head portion, and the third transmission channel is closed to fluid flow in the first extreme position of the valve stem and open to fluid flow in the second extreme position of the valve stem.

[0045] Optionally, the inlet of the housing is coaxial with the valve stem chamber.

[0046] Optionally, the bottom housing portion includes an upright tubular socket that surrounds the inlet and extends upwardly into the interior of the housing, wherein the upright tubular socket is sized such that the discharge assembly is configured to discharge a metered volume of between 30 microliters and 150 microliters. This makes the discharge assembly suitable for a wide range of uses. By varying the height of the upright socket, the discharge volume can be directly varied.

[0047] According to a second aspect of the present disclosure, a liquid dispensing device is disclosed, provided with a discharge assembly as described herein for discharging a metered volume of liquid contained in a pressurized or pressurizable container of the device.

[0048] Optionally, the container is pressurized with nitrogen, air, liquefied natural gas, liquefied hydrocarbon gas or carbon dioxide.

[0049] Optionally, the device is an aerosol spray device.

[0050] Optionally, the device comprises a compound or composition comprising a material selected from the group consisting of pharmaceuticals, agricultural chemicals, fragrances, air fresheners, odor neutralizers, disinfectants, polishes, insecticides, depilatory chemicals (such as calcium thioglycolate), depilatory chemicals, cosmetic agents, deodorants, antiperspirants, antibacterial agents, antiallergic compounds, and mixtures of two or more thereof.

[0051] Advantageously, the disclosed assembly provides a liquid dispensing device that can use compressed gas as a propellant, meaning that no hazardous or environmentally harmful propellant gases (such as butane) need be used. The device can deliver uniformly metered volumes of liquid propellant over its useful life, is inexpensive to manufacture, can be manufactured at high yields within narrow performance tolerances, and its components are resistant to the effects of aging over the life of the product. Furthermore, the disclosed device produces a high quality liquid aerosol without the need to bleed air from the aerosol container, thereby substantially maintaining aerosol spray performance throughout the useful life.

[0052] The device according to the present disclosure is preferably in the form of an aerosol spray device.

[0053] The liquid discharge element employed in the liquid dispensing device of the present disclosure is preferably rigid to ensure that a known volume of liquid is dispensed without fluctuations in volume between successive discharges due to flexibility of the liquid discharge element.

[0054] In a preferred configuration of the device according to the present disclosure, the device is configured so that the movement of the liquid discharge element (preferably in the form of a cylindrical piston or ball as described above) from its liquid filling position in the metering chamber to its liquid discharge position resists the return force. In other words, the return force is applied during the discharge of the device, and not just during its refilling. Conveniently, since the liquid discharge element has negative buoyancy in the liquid to be dispensed, it has a tendency to "sink" in the metering chamber, thereby providing the return force. The liquid discharge element can be made of a metal such as stainless steel, for example. Alternatively, it can be a synthetic polymer material of appropriate weight (for example by a metal insert or by incorporating a densifier therein), preferably weighing at least 0.03g. Alternatively or additionally, the return force can be provided by a spring.

[0055] The metering chamber is preferably arranged in the valve stem, and the liquid discharge element is movable along the inner surface of the metering chamber. Preferably, the liquid discharge element is in the form of a piston, which is preferably spherical or cylindrical. If the device is used to meter precise volumes (for example for medical purposes), the liquid discharge element may be sealed to the valve stem and / or the inner wall of the metering chamber. Preferably, the gap between the liquid discharge element and the metering chamber is sufficient to form a seal between the liquid discharge element and the metering chamber, but not so small that the travel of the liquid discharge element between the first and second extreme positions is seriously hindered by friction with the wall of the metering chamber.

[0056] The preferred configuration of the equipment according to the present disclosure will make the liquid discharge element have a first side exposed to the metering chamber and a relative second side exposed to the fluid pressure from the container. In this arrangement, the metering chamber will be provided with an inlet / outlet arrangement on the first side of the liquid discharge element, for introducing liquid into the metering chamber from the container and discharging liquid from the metering chamber. In some embodiments of the present invention, the inlet and outlet can be separated from each other. However, in other embodiments of the present invention, a single port can be used as an inlet and outlet simultaneously.

[0057] Typically, a device according to the present disclosure will include an actuator assembly including a valve stem in which movement from a first extreme position to a second extreme position preferably abuts against a biasing device (e.g., a coil spring). The actuator assembly preferably includes a valve stem. The actuator assembly may also include an actuator cover.

[0058] In a preferred embodiment of the present disclosure, the valve stem has a discharge conduit device having an inlet and an outlet, the liquid is introduced into the discharge conduit device through the inlet, and the liquid is discharged from the device through the outlet. This embodiment is also combined with a valve device, wherein the valve device allows liquid to flow from a pressurized container into the metering chamber through the inlet / outlet device to achieve filling of the metering chamber when the valve stem is in its first extreme position, and can flow out of the metering chamber without passing through the inlet / outlet device. Conversely, when the valve stem is in its second extreme position, the liquid can flow out of the metering chamber through the inlet / outlet device to the discharge conduit to achieve discharge of the metering chamber, and can flow into the metering chamber without passing through the inlet / outlet device.

[0059] A pressure equalization channel may be provided in the outer surface of the metering chamber to allow equalization of pressure in the discharge conduit means of the valve stem and pressure in the container when the valve stem is in the first extreme position.

[0060] The valve stem can be rotated about its axis between first and second rotational positions, and wherein the device is such that in the first rotational position of the valve stem the valve stem is prevented from axial movement beyond its second extreme position, but in the second rotational state the valve stem is allowed to move axially to provide for filling and / or refilling of the device. Advantageously, requiring such axial rotation to effect filling and / or refilling of the device can prevent a user from accidentally pressing the valve stem into the filling position during normal use.

[0061] Positioning the metering chamber within the valve stem has the advantage of simplifying the structure compared to a situation where the metering chamber is arranged around the valve stem (around its periphery). Advantageously, such a metering chamber may be particularly suitable for providing a metering chamber for an apparatus having a metering chamber of a small and accurately metered volume. The valve stem may be biased from the second extreme position to the first extreme position, preferably by means of a spring, most preferably by means of a helical spring.

[0062] Preferably, the lower wall of the housing is provided with a depending socket, which defines an inlet of the housing. Liquid from the pressurized container preferably enters the housing through the socket. Preferably, the socket extends from the lower wall of the housing and is engageable with at least a portion of the valve stem. Preferably, a coil spring is located on the socket so that when the valve stem is in the second extreme position, the spring biases the valve stem towards the first position.

[0063] Preferably, a seal is provided at the end of the housing from which a portion of the valve stem extends. Preferably, the seal is an annular seal that seals around the circumference of the valve stem at the point where the valve stem leaves the housing. The seal allows the valve stem to slide relative to each other within the housing and between the first and second extreme positions.

[0064] Preferably, the metering chamber has a substantially cylindrical cross section.

[0065] Preferably, the diameter of the liquid discharge element is very close to the diameter of the metering chamber so as to provide a sealing or nearly sealing contact with the inner circumference of the metering chamber.

[0066] Preferably, the valve stem comprises a body portion and a head portion of narrower diameter. The head portion is preferably surrounded at its base by a shoulder defined at the upper end of the body. The head portion is preferably movable within an annular seal provided at the second end of the housing. Preferably, the head portion has a third fluid transfer channel communicating with an outlet of the head portion, the third transfer channel being located outside the housing in the first position of the valve stem and inside the housing in the second position of the valve stem. Preferably, the inlet of the housing is coaxial with the chamber.

[0067] Preferably, the discharge assembly of the present disclosure is such that when the valve stem is in its second extreme position and the discharge element is in its liquid filling position, a refill flow channel device is provided between the liquid inlet of the shell and the chamber provided in the valve stem body to allow refilling of the container installed with the discharge assembly during use. DETAILED DESCRIPTION

[0068] The disclosed invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0069] 1A and 1B illustrate a prior art arrangement of a discharge assembly in successive stages of operation;

[0070] 2A, 2B and 2C illustrate another prior art arrangement of the discharge assembly in successive stages of operation;

[0071] Figures 3 to 5 An improved arrangement of the exhaust assembly according to the invention is shown;

[0072] FIG. 6A to FIG. 6C shows a cross section of the improved discharge assembly in its resting position;

[0073] FIG. 7A to FIG. 7C shows a cross section of the improved discharge assembly in an intermediate, partially actuated position;

[0074] FIG. 8A to FIG. 8C shows a cross section of the improved discharge assembly in its fully actuated position;

[0075] 9A to 9E Different arrangements of sealing surfaces that may be used in exhaust assemblies are shown;

[0076] Figures 10 to 12 An exemplary top housing portion for an improved exhaust assembly is shown; and

[0077] Figures 13 to 15 An exemplary bottom housing portion for a modified exhaust assembly is shown.

[0078] In the following description, references to "upper" and "lower" refer to the embodiments of the device as shown in the figures, which are shown in their normal operating position. References to "top" and "bottom" should be interpreted similarly to "upper" and "lower", respectively. In the following description, the "rest" state refers to the device is filled and ready to discharge a metered volume, with the valve stem in the uppermost position and the piston (i.e., the discharge element) in the lower limit position. Ranges, such as ranges expressed between first and second endpoints, should be interpreted as including (i.e., comprising) these endpoints.

[0079] In the following description, references to the valve stem being in the highest and lowest positions correspond to references to the valve stem being in the first and second extreme positions, respectively. References to the valve stem being in the depressed or actuated position correspond to references to the valve stem being in the lowest position. References to the piston correspond to references to the liquid discharging element. References to the lower and upper limit positions correspond to references to the liquid filling and liquid discharging positions, respectively.

[0080] It should be understood that in addition to substantially insoluble compressed gas propellants, liquefied gas propellants may also be used in embodiments of the present invention.It should be understood that the liquid discharge assembly disclosed herein is particularly suitable for use in liquid dispensing devices as generally defined herein.

[0081] Reference is now made to FIG. 1A , which shows one embodiment of a prior art discharge (or metering valve) assembly 2003 in a static state. In order to provide context for the improved valve assembly of the present disclosure, the function of this prior art assembly will be described in detail. The deficiencies in this assembly and the manner in which the improved valve of the present disclosure addresses these deficiencies will then be described.

[0082] Turning again to Fig. 1A, the metering valve assembly 2003 includes a housing 2007 in which the valve stem 2004 is located. The housing 2007 is generally tubular and has an inner surface that is stepped at two locations along its length. More specifically, the inner surface of the housing 2007 has a downwardly sloping annular step 2100 and a right-angled step 2101 further downward toward the wall 2009 at the lower end of the housing.

[0083] The lower wall 2009 may also be considered as the base portion of the housing 2007, which is provided with a depending socket 2010 which defines an inlet 2011 of the housing 2007. Optionally, the socket 2010 may have an enlarged lower end (not shown) on which the upper end of a dip tube (not shown) is located, the dip tube extending to a lower region of a container (not shown) on which the metering valve assembly 2003 is mounted in use. An upright tubular socket 2102 surrounds the inlet 2011 and extends upwardly into the interior of the housing 2007.

[0084] The valve stem 2004 includes a body portion 2103 and a narrower diameter head portion 2104 surrounded at its base by a shoulder 2105 defined at the upper end of the body 2103. At the junction of the body portion 2103 and the head portion 2104 is a dividing wall 2023 that separates an upper, open-top conduit 2025 (in the head portion 2104) from lower chambers 2034a and 2034b disposed in the body portion 2103. As shown, chamber 2034b is the upper of the two chambers and is of smaller diameter, thereby defining a shoulder 2034s in the process from chamber 2034a to 2034b.

[0085] Over most of the length of the main body portion 2103 of the valve stem 2004, in the region between the steps 2100 and 2101, its outer diameter is slightly smaller than the inner diameter of the housing 2007. In its lower region, the main body portion 2103 is stepped inwardly at 2106.

[0086] The valve stem 2004 is provided with two sets of fluid transfer passages, one set extending radially outward from the discharge conduit 2025 and the other set extending radially outward from the chamber 2034b. More specifically, at its upper region, the body 2103 (of the valve stem 2004) is formed with a first fluid transfer passage 2026, and the lower region of the head portion 2104 is formed with a second fluid transfer passage 2028.

[0087] Additionally, the main body 2103 (of the valve stem 2004) is formed with an annular groove 2107 in which an O-ring 2108 is located. The outer diameter of the O-ring 2108 is smaller than the inner diameter of the housing 2007 above the step 2100, but slightly larger than the inner diameter below the step 2100.

[0088] As shown in Fig. 1A and Fig. 1B, the main body 2103 of the valve stem 2004 is located in the housing 2007, and the head portion 2104 thereof protrudes out of the annular seal 2029, which is arranged at the upper end of the housing 2007 and seals on the outer surface of the head portion 2104. As further shown in the drawings, the main body 2103 of the valve stem 2004 subdivides the internal space of the housing 2007 into a first annular area 2109 above the step 2100, a narrower second annular area 2110 between the steps 2100 and 2101, and a third annular area 2111 below the step 2101.

[0089] The length of the valve stem 2004 is such that when the metering assembly 2003 is in its resting state (as shown in FIG. 1A ), the lower end of the valve stem 2004 is located above the upper end of the socket 2102. A coil spring disposed around the socket 2102 and around the lower end of the valve stem 2004 is used to bias the valve stem 2004 to its upper position.

[0090] As shown, a ball 2031 is provided which has negative buoyancy relative to the liquid in the container for discharge by the assembly 2003. The diameter of the ball 2031 is larger than the inner diameter of the tubular socket 2102, but is positioned with minimal clearance in the lower chamber 2034a of the valve stem 2004. In the static state of the assembly 2003 (see FIG. 1A ), the ball 2031 rests on the upper end of the tubular socket 2102, and its upper surface is just located in the lower end of the chamber 2034a.

[0091] By the arrangement described, the ball 2031 is able to travel between a lower limit position (defined by the upper end of the tubular socket 2102) and an upper limit position at the shoulder 2034s. Thus, the lower chamber 2034a provides a metering chamber in which the ball 2031 can move from its lower limit position to the upper limit position to sweep out a metering volume.

[0092] Other features of the illustrated embodiment are one or more cutouts or slots 2112 (shown in FIGS. 1A and 1B ) at the upper end of the socket 2102 and slots 2113 or other passages for providing fluid flow radially through the wall toward the lower end of the body portion 2102. More specifically, the slots 2113 (or other passages) are disposed at a height such that, with the valve stem 2004 in the recessed position ( FIG. 1B ) and the ball 2031 secured to the socket 2102, fluid is able to flow radially outwardly to the body 2103 of the valve stem 2004 for reasons that will be more fully described below.

[0093] Figure 1B shows the assembly of Figure 1A in an actuated position. Operation of the apparatus shown in Figures 1A and 1B, ie from rest to actuation, is as follows.

[0094] In the resting state shown in FIG1A , the ball 2031 is in its lower position and the metering valve assembly 2003 is filled with liquid up to the level of the seal 2029. Once the valve stem 2004 is depressed, the fluid delivery channel 2028 moves downward past the seal 2029, thereby opening to the flow of fluid from within the housing 2007. In addition, the O-ring 2108 now abuts against the inner surface of the second annular region 2110 to prevent fluid from flowing from the inlet 2011 into the first annular region 2109. Therefore, the ball 2031 is now pushed upward by the fluid pressure, causing it to move from its lower position (as shown in FIG1A ) to its upper position (as shown in FIG1B ), which in turn causes a certain amount of liquid to be delivered radially outward through the fluid flow delivery channel 2026 and then radially inward through the fluid flow delivery channel 2028 for discharge by the assembly through the outlet 2025. Once the valve stem 2004 is released and returns to its uppermost position under the action of the spring, the fluid transfer passage 2028 is again closed to fluid flow (due to being located above the seal 2029), but liquid is now able to reach the fluid transfer passage 2026 from the inlet 2011 of the housing along the annular areas 2109, 2110 and 2111. This liquid is able to flow radially inwardly along the fluid transfer passage 2026 above the level of the ball 2031, which will now move downward to its lower limit position, thereby filling the chamber 2034a to discharge a further metered volume of liquid.

[0095] Once the liquid and gas in the container in which the spray discharge assembly is installed are exhausted, they can be refilled in the following manner. First, the valve stem 2004 is depressed to the position shown in Figure 1B. Secondly, a source of pressurized liquid and / or propellant gas (as the case may be) is connected to the outlet end of the valve stem 2004 (usually). The refill liquid and / or propellant gas thus passes along the discharge conduit 2025, radially outward through the second fluid transfer channel 2028 into the annular region 2109, and then radially inward through the channel 2026. If the ball 2031 is not already fixed on the socket 2031, the fluid pressure will cause it to move to this position. The pressurized refill liquid and / or propellant gas passes along the chamber 2034a, then radially outward through the groove 2113, and then radially inward through the cut-out portion 2112, so that it can enter the container through the inlet 2011.

[0096] 2A and 2B show an embodiment similar to that shown in FIG1A and 1B. In this embodiment, the length of the valve stem 2004 is such that when the metering assembly 2003 is in its resting state (as shown in FIG2A), the lower end of the valve stem 104 is located below the upper end of the socket 2102. The socket can be slidably inserted into the lower end of the valve stem 2004. A coil spring disposed around the socket 2102 and around the lower end of the valve stem 2004 is used to bias the valve stem 2004 to its upper position.

[0097] It should be understood that the apparatus shown in Figures 2A to 2C works similarly to the apparatus in Figures 1A and 1B. The main difference is that pressure equalization between the pressurized container and the upper chamber 2034b is promoted by the fluid being able to move between the outer surface of the socket 2102 and the inner surface of the metering chamber 2034a. This can be achieved by providing sufficient clearance between the outer diameter of the socket 2102 and the inner diameter of the metering chamber 2034a. Alternatively or additionally, this can be achieved by providing grooves in the outer surface of the socket 2102, which provide one or more conduits extending between the metering chamber 2034a and the annular region 2111, and / or by providing an inlet in the valve stem wall, such as the channel 2113 shown in Figure 1B. In this way, the fluid can move upwardly through the inlet 2011 into the chamber 2034a, through the groove 2112 into the annular regions 2111, 2110 and 2109, to reach the fluid transmission channel 2026. Since this is above the level of ball 2031, the ball will move downwards, ready to discharge a further metered volume of fluid.

[0098] The refilling of the device of FIGS. 2A and 2B is similar to that of FIGS. 1A and 1B , except that, in certain embodiments, an annular groove may further facilitate refilling, as shown in an enlarged form in FIG. 2C . As shown, the wall of chamber 2034a has an annular groove 2032 having a diameter greater than the rest of the chamber. The annular groove 2032 facilitates refilling of the device as follows. First, the valve stem 2004 is depressed to the position shown in FIG. 2B . It may then be depressed beyond this position (e.g., by rotating the valve stem to a predetermined position) and further depressed so that the upper end of the socket 2102 retains the ball 2031 adjacent the annular groove (as shown in FIG. 2C ). Next, a source of pressurized liquid and / or propellant gas (as the case may be) is connected to (usually) the outlet end of the valve stem 2004. As a result, the refill liquid and / or propellant gas travels along the discharge conduit 2025, radially outward through the second fluid transfer passage 2028 into the annular region 2109, and then radially inward through the passage 2026. Fluid pressure moves ball 2031 to the position shown in Figure 2C. Pressurized refill liquid and / or propellant gas passes along chamber 2034a, past ball 2031 at the annular groove, and then radially through groove 2112 so it can enter the container through inlet 2011. It should be understood that the inclusion of groove 2032 is optional and the assembly of Figures 2A / 2B can also be refilled in the manner described in Figures 1A / 1B.

[0099] 2A-2C , the clearance between the outer diameter of the socket 2102 and the inner wall of the metering chamber 2034a is sufficient to allow fluid to flow from the metering chamber 2034a to the annular space 2111, and thus, when the ball 2031 is in the liquid discharge position shown in FIG2B , fluid communication is provided between the metering chamber 2034b and the fluid flow transmission channel 2026. This allows pressure equalization between the pressurized container and the upper chamber 2034b, thereby facilitating movement of the ball 2031 rearwardly toward the socket 2102.

[0100] The present inventors have identified a number of significant deficiencies in the prior art exhaust assembly of FIGS. 1A-2C , which will now be explained.

[0101] First, the inventors have identified that inserting the O-ring 2108 during the manufacture of the valve presents significant difficulties. Manufacturing the required groove 2107 to hold the O-ring requires a high degree of precision to ensure that the O-ring extends the correct distance from the valve stem to form an effective seal with the housing 2007 in the actuated position. The process has very tight tolerances, which means that even a slight deviation from the expected groove or O-ring size can cause the valve mechanism to malfunction. Inserting the O-ring 2108 into the groove 2107 is also a tedious and high-precision task, which increases manufacturing time. In addition, the inventors have identified that even if the O-ring 2108 is correctly fixed in place, it has a tendency to expand during use due to exposure to the fluid. This can cause the valve to become clogged and malfunction. Therefore, the inclusion of the O-ring 2108 presents various difficulties. The inventors considered replacing the O-ring with a solid flange of resin or plastic to solve the above-mentioned problems with the use of an O-ring. However, this also presents problems because the position and size of the flange must be very accurate so that a correct seal is formed during actuation. This is not simple as molded parts can have a phenomenon known as "ovality." This is when a molded part, particularly a round part, tends to stretch and take on an elliptical shape rather than the intended spherical shape. In the context of the present exhaust assembly, this ovality can result in a sealing flange that is the wrong shape and cannot properly seal the valve during actuation. As a result, molding time must be increased to compensate for the ovality and valve failure rates are high, resulting in many valves being discarded after manufacture as being unfit for purpose. The ovality of the sealing flange can also make it difficult to remove the molded pins during manufacturing. The inventors have recognized that a better sealing mechanism is needed.

[0102] Another disadvantage of the discharge device of Figures 1A to 2C is that the valve stem and housing must have a minimum length in order to accommodate and subsequently discharge a useful volume of fluid. Typically, the length of a metering valve device of this nature is between 30mm and 40mm. This is in stark contrast to a non-metered dose valve device, which can discharge a continuous stream of fluid and is therefore much shorter, typically about 10mm long. The long valve stem and housing mean that the base portion of the housing (i.e., the base portion 2009 in Figures 1A to 2C) must be very thick in order to have sufficient structural integrity to support the walls and other features provided in the housing. The inventor has recognized that when using the arrangement shown in Figures 1A to 2C, the thickness of the base portion 2009 must be at least 3mm. This thickness is not ideal because during the molding process, the thick part of the material takes longer to cool. This means that deformation may occur for a longer time, and this risk will only increase when the molding pin must be pulled out during molding. In order to alleviate this situation, the molding pin will usually stay in the mold for a longer time to allow the plastic material to cool for a longer time. However, this greatly increases the cycle time of the manufacturing process. The inventors have identified that when using the arrangement shown in Figures 1A-2C, the manufacturing cycle time to produce the exhaust assembly is approximately 40 seconds due to the need to wait for the base to cool.The inventors have recognized that a superior structure for a valve housing is needed.

[0103] A third disadvantage of the discharge device of Figures 1A to 2C is that the stroke length of the discharge assembly is very limited, about 0.2 mm. In this case, "stroke length" refers to the maximum distance that the valve stem can be pressed into the housing during actuation. In the above arrangement, the reason why the stroke length is so limited is that the O-ring (or resin flange) is sealed only at a single point along the housing, that is, at the contact point between the O-ring (or flange) and the valve housing. This contact point is very small, which means that the size of the valve needs to be very precise to ensure proper sealing when the fluid outlet is opened. This limits the stroke length. In addition, a long stroke length will result in a large degree of friction between the contact point of the O-ring or flange and the valve housing, because the contact point is very small, which means that all friction is applied to the single contact point. This will quickly degrade the O-ring, flange, housing, or both, causing the valve assembly to fail. Therefore, only a very short stroke length is possible to minimize the friction of the O-ring / flange on the housing. The inventors have recognized that it is necessary to increase the stroke length to allow a wider variety of applications for the assembly, as described more fully below.

[0104] The fourth disadvantage of the discharge arrangement of Figures 1A to 2C is that the surface that the ball 2031 seals (i.e., the shoulder 2034s visible in Figure 1A) must be precisely machined. This is because the shoulder has a sharp right-angle edge. When properly machined, this will form an effective seal for the ball in the actuation (liquid discharge) position. However, the inventors have found that in practice, it is actually difficult to obtain a sharp right-angle edge at the sealing surface. In many cases, small deformations will occur in the molding. This will destroy the sharpness of the edge, resulting in poor sealing or even complete failure. This results in a continuous discharge stream, rather than a metered dose. The inventors have recognized that a good sealing surface geometry is required.

[0105] Finally, a fifth disadvantage of the discharge arrangement of FIGS. 1A to 2C is that the inventors have found that during manufacturing, the molding pins can often get stuck in the molded component. This is because, as mentioned above, metered discharge assemblies are longer than typical valve assemblies because they need to have sufficient internal volume to hold the required metered dose. This results in a long housing and a long valve stem, in which the molding pins are more likely to get stuck due to high friction. The inventors have recognized the need for an improved molding process.

[0106] Now refer to Figures 3 to 15 An improved discharge assembly for discharging a metered volume of a liquid is described which overcomes the above-mentioned disadvantages of prior art valves.

[0107] First go to Figure 3 , Figure 4 and Figure 5 , the improved exhaust assembly 4003 is shown from top to bottom, side and perspective views. Fig. 6A A cross-sectional view of an improved exhaust assembly 4003 is shown, wherein Figure 6B and Figure 6C Two enlarged portions are shown. FIG. 6A to FIG. 6C Corresponds to Figure 4 AA shown in FIG. This assembly shares various structural features with the exhaust assembly of FIGS. 1A to 2C , and like reference numerals are used to denote like parts. Except for the differences to be described, the actuation mechanism and fluid flow paths during actuation and resetting are as described above with reference to FIGS. 2A and 2B .

[0108] Nevertheless, various key modifications are provided compared to the valve of Figures 1A to 2C to address the problems of previous arrangements discussed above. These improvements will now be described in detail.

[0109] First, the improved assembly utilizes a two-part housing, rather than the single-piece housing used in previous designs. Specifically, the upper (or top) housing portion 2007a is secured to the lower (or bottom) housing portion 2007 / b. The upright socket 2102 is part of the lower housing portion 2007b, while the majority of the outer wall of the housing is provided as part of the upper housing portion 2007a. The upper housing portion 2007a is also configured to attach to the mounting cup 3200, as shown in FIG. Fig. 6A , Fig. 7A and Fig. 8A shown.

[0110] The structure of the improved valve assembly 4003 means that the base 2009 does not need to provide the same degree of structural integrity compared to the design of Figures 1A to 2C. In particular, due to the two-part housing, the top portion 2007a bears some of the structural loads of the housing. This means that the bottom 2007b is subjected to less load and does not need to provide such a strong structural foundation. Therefore, the base portion 2009 can be significantly thinner, typically not more than 2mm thick, preferably between 1mm and 2mm thick. Since the improved structural arrangement of the discharge assembly 4003 makes these thinner dimensions possible, the risk of deformation of the base portion 2009 during molding is significantly reduced. This means that the molding pins can be removed more quickly, the cycle time is shortened, and less material needs to be used.

[0111] exist FIG. 6A to FIG. 6C In the exemplary arrangement shown, the top housing portion 2007a and the bottom housing portion 2007b are joined by a permanent interference fit. In this case, "permanent" means that the seal will not be broken by normal use of the device (e.g., actuation). In other words, during use of the device, the top and bottom housing portions remain fixed together. In the arrangement shown, the bottom housing portion 2007b includes a channel 3400 that is configured to receive the top housing portion 2007a. The channel is in Fig.14 3400. The channel 3400 provides a simple mechanism by which an interference fit between the housing parts can be established. In this example, the channel also includes a recess 3500, which is configured to receive a corresponding protrusion 3300 on the top housing part 2007a. It should be understood that, alternatively or additionally, the channel may include a protrusion that is configured to engage with a corresponding recess on the top housing part 2007a. When inserted together, the protrusion and recess lock together to provide a permanent interference fit. It should be understood that other forms of interference fit may be provided. Preferably, the interference fit is configured to withstand an applied force of 100N. This will ensure that the seal will remain unchanged during normal use of the valve, including discharge (such as by an actuator of an automatic discharge system) and refilling.

[0112] A second improvement over previous exhaust assemblies is that the improved exhaust assembly uses fins 3100 instead of O-rings or sealing flanges. Fins 3100 can be Fig. 6A seen in the cross section and in Figure 6C During actuation, the fins 3100 form a temporary interference seal between the interior of the housing and the exterior of the valve stem 2004 to close the fluid transmission passage along the exterior of the valve stem 2004 to prevent fluid flow.

[0113] More specifically, when the valve stem is in its second extreme position, a temporary seal is created, as described above with respect to FIGS. 1A to 2C with respect to the O-ring. In this article, "temporary" means that the seal is formed and broken during normal use. In this case, the seal is formed when the valve stem 2004 is depressed and moves toward its second extreme position during actuation. Then, when the actuating force is removed and the valve stem 2004 returns to its first extreme (i.e., static) position, the seal breaks. Each time the valve is actuated, the cycle of sealing and non-sealing is repeated. Therefore, this temporary interference seal is contrasted with a permanent interference seal between the top and bottom housing parts, which persists throughout the actuation and reset to the static position.

[0114] exist 6A to 8C In the example shown, as in the case of Figures 1A to 2C, the temporary seal between the fin 3100 and the valve stem 2004 is intended to close the flow of fluid between the volumes 2111, 2110 and 2109 surrounding the valve stem 2004. It will be appreciated that in this arrangement, the first annular region 2109 is located above the chamfered seat 3900 (in this example, provided on the valve stem 2004), the annular region 2110 is located between the seat 3900 and the step 2106, and the annular region 2111 is located below the step 2106.

[0115] Specifically, Fig. 6A and Figure 6C As shown, the fin 3100 includes a lip of material extending from a surface that is disposed on the fin 3100, typically extending upward or downward at an acute angle. In the illustrated arrangement, the fin 3100 is disposed on the inner surface of the top housing portion 2007a and protrudes upward into the interior of the housing at an acute angle. Thus, the fin 3100 is configured to abut and seal the exterior of the valve stem 2004 during actuation. It should be understood that in some arrangements, the fin 3100 may be disposed on the exterior of the valve stem 2004 and configured to abut against the interior of the housing. Preferably, the fin 3100 is integrally formed with the top housing portion 2007a (or any component formed thereon). This simplifies manufacturing because the fin 3100 can be molded simultaneously with the housing (or valve stem, as the case may be). This contributes to faster cycle times compared to attaching the fin 3100 later as a separate component.

[0116] In order to provide an improved seal, the device shown also includes a seat 3900 configured to interface with the fin 3100 to provide an interference seal when the valve stem 2004 is in the second extreme position. In the example shown, the seat 3900 is disposed on the outer surface of the valve stem. However, it should be understood that in an arrangement where the fin 3100 is located on the valve stem, the seat 3900 can be disposed inside the housing. Preferably, the seat 3900 includes a chamfered or tapered surface, in other words, an angled surface, configured to abut and slide against the fin 3100. This provides an excellent seal during actuation. Preferably, the fin 3100 extends into the path of the seat by at least 0.1 mm, preferably between 0.1 mm and 0.2 mm, including the end points. This ensures that the fin 3100 and the seat form a tight interference seal during actuation without generating too much (or too little) friction, both of which can lead to failure of the discharge assembly.

[0117] Preferably, the length of the interference seal formed between the fin 3100 and the valve stem 2004 is between 0.2 mm and 3 mm, preferably between 1 mm and 2 mm. The length of the interference seal can be considered to be the length of the fin 3100 abutting against the valve stem in the second extreme position in the actuation direction of the valve stem. In other words, the sealing length can be considered to be the length of the fin material that forms a seal against the valve stem. The above sealing length ensures a good seal without generating too much (or too little) friction, which can also lead to malfunction of the discharge assembly.

[0118] The use of fins 3100 provides a more reliable seal than the use of o-rings or resin flanges. In particular, the temporary seal is formed along the length of the fin, rather than just at a single point of contact as between the o-ring / flange and the housing in prior art devices. This means that the seal is less susceptible to degradation due to friction. Tolerances are more forgiving because the fins do not need to be molded as precisely as an o-ring or resin flange. Ovality is far less of an issue when molding the fins than with a resin flange / o-ring, and it is easier to remove the molding pins when forming the fins due to the natural angular shape of the fins. This means that manufacturing time can be reduced.

[0119] The inventors have identified that the manufacturing cycle time for producing the improved vent assembly 4003 is reduced to approximately 8 to 10 seconds due to the ability to use a thinner base portion 2009 and the use of fins 3100. As previously described, this is compared to the 40 second cycle time for producing the original vent assembly 2003.

[0120] Additionally, as described above, by using fins 3100, the seal between valve stem 2004 and housing can be maintained longer. As described above, this makes the seal more reliable, and crucially, it allows a longer stroke length than a sealing O-ring or flange. The stroke length represents the maximum distance that valve stem 2004 can be pressed down during actuation. Longer stroke lengths open up greater possibilities in terms of use cases for discharge assembly 4003. For example, the assembly can be used for automatically actuated devices, such as automatic air fresheners. Such automatic devices usually require a minimum stroke length of 2mm to work reliably. In particular, the inventor has identified that a discharge assembly with a stroke length less than 2mm will not allow an automatic lever or arm in an automatic dispenser to extend 2mm. This may cause the automatic dispenser to think that it has not dispensed a metered volume. Therefore, the automatic arm or lever constantly attempts to press down. This will continue until the battery is exhausted, which may occur quickly due to the continuous pressing of the lever or arm. In contrast, the use of fins 3100 and improved assembly 4003 as described above means that a discharge assembly having a stroke length of 2 mm or more can be provided, which avoids the above-mentioned failures when using an automatic dispenser. This is in stark contrast to the previous assembly 2003, which has a very limited stroke length for the reasons described above. The inventors have recognized that a stroke length of 2 mm is generally not possible or feasible using the previous discharge assembly 2003 compared to the improved discharge assembly 4003.

[0121] Fig. 7A Shows FIG. 6A to FIG. 6C The improved discharge assembly 4003, but now in the semi-actuated position, rotated 90 degrees. Figure 7B and Figure 7C Corresponds to Fig. 7A DD is shown and shows an enlarged assembly. As shown, the fin 3100 is configured to create a temporary seal when or before the fluid path 2028 is opened to fluid flow by moving under the seal 2029. This ensures that the assembly 4003 works properly.

[0122] FIG. 8A to FIG. 8C The same modified vent assembly 4003 is shown now in its fully actuated position, i.e., the valve stem 2004 is in its second extreme position. Figure 8C As shown, the fin 3100 forms a long and strong sealing surface (the temporary seal described above) against the valve stem. The fluid flow around the outside of the valve stem 2004 (i.e., the path between volumes 2109, 2110, and 2111) is now completely sealed, so the discharge element 2031 is pushed upward by the fluid pressure to discharge the metered dose, as described more fully above with reference to Figures 1A to 2C.

[0123] like Fig. 8AAs shown, as with the previous arrangement, when in the liquid discharge position, the liquid discharge element 2031 abuts against the sealing surface 2034s. However, this arrangement is improved in that in the improved discharge assembly 4003, the sealing surface 2034s is chamfered. The chamfered sealing surface provides an improved seal to the discharge element 2031 and is easier to machine and has greater tolerances than the sharp edges required for a 180 degree angle. In particular, small defects in the chamfered sealing surface are less likely to cause a seal failure than defects of similar size in the sharp edge surface.

[0124] 9A to 9E Various sealing surfaces 2034s are shown that may be implemented in the valve assemblies of the present disclosure.

[0125] Fig.9A A conventional sharp edge sealing surface used in the prior art is shown. The sealing edge is a sharp angle to produce a 180 degree sealing angle. As mentioned above, it has been found that machining or shaping the sealing surface accurately enough to ensure a good seal is very challenging, resulting in unreliable sealing.

[0126] FIG. 9B to FIG. 9E An alternative improved sealing surface developed by the inventors is shown. Each of these sealing surfaces provides a Fig.9A Improved sealing of the sealing surface.

[0127] First go to Fig. 9B An alternative sealing surface 2034s developed by the inventors includes a gasket or O-ring placed against the valve stem. Thus, the sealing surface incorporates a gasket or O-ring against which the liquid discharge element 2031 seals during actuation. The O-ring may be made of any suitable material, such as rubber. It has been found that the O-ring or gasket seal provides a very reliable seal to the liquid discharge element 2031.

[0128] One disadvantage of using an O-ring or gasket is that it must be inserted into the valve stem during manufacturing. This is challenging because the diameter of the O-ring or gasket is often similar to the inside of the valve stem, making insertion of O-rings and gaskets difficult and time consuming. This negatively impacts the cycle time of valve assembly manufacturing.

[0129] FIG. 9C to FIG. 9E Alternative sealing surfaces 2034s developed by the inventors are shown that do not require O-rings or gaskets, but they can be used in conjunction with O-rings or gaskets if desired.

[0130] Fig. 9CThe sealing surface includes a chamfered sealing surface 2034s, as previously shown in Figures 6 to 8. Preferably, the chamfer is at an angle between 120 and 180 degrees relative to the longitudinal axis of the valve stem. More preferably, the angle is between 120 and 160 degrees, as shown in Figures 6 to 8. Fig. 9C As shown, the figure uses an angle of 120.12 degrees. Chamfers within these ranges provide a particularly good seal to the discharge element 2031 and are easy to manufacture.

[0131] Fig.9D Another alternative sealing surface 2034s is shown. The sealing surface 2034s includes a convex curved profile. This causes the sealing surface to protrude into the path of the liquid discharge element. The inventors have determined that Fig. 9C Compared to a flat surface with a chamfer, this convex sealing surface 2034s is less susceptible to ovality effects. Fig. 9C Compared to the flat chamfered surface of the valve stem, ovality effects, such as those caused by stem cooling or distortion during manufacturing, are Fig.9D The convex sealing surface of the seal is less likely to cause leakage. In other words, the tolerance of the curved surface is smaller than that of the chamfered surface.

[0132] Preferably, when the sealing surface has a curved convex profile, its radius is 1.5 mm to 1.8 mm measured from its center of curvature at the point of maximum curvature. In other words, the radius of the circle overlapping the most curved part of the convex surface will be within this range. The inventors have identified that this radius range provides a particularly good seal for the liquid discharge element 2031.

[0133] Fig.9E Another alternative sealing surface 2034s is shown. This sealing surface 2034s includes a concave curved profile, also referred to as a "dish" profile. The concave volume defined by this surface 2034s can accommodate the liquid discharge element 2031, thereby providing a good seal. The concave surface provides many of the same advantages as the convex surface described above. In particular, the sealing surface can also be manufactured with a looser tolerance than a flat chamfered surface while still providing a good seal.

[0134] Preferably, where the sealing surface 2304s has a concave curved profile, the lowermost surface of the sealing surface (i.e., the connection point between the sealing surface and the vertical valve stem wall) defines an angle between 20 and 40 degrees relative to the longitudinal axis of the valve stem, in which the liquid discharge element is received. More preferably, the angle is between 25 and 35 degrees, and more preferably, the angle is about 30 degrees, such as Fig.9E The inventors have identified that this angle range provides a particularly good seal for the concave sealing surface.

[0135] Preferably, one or more internal volumes of the discharge assembly are tapered. This can include the internal volume of the valve stem 2004, one or more housing portions 2007a, 2007b, any sockets in the assembly 4003, and any fluid passages. In the example shown, the internal volume of the top housing portion 2007a, the internal volume of the inlet 2011 in the bottom housing portion 2007b, and the fluid transfer passages 2026 and 2028 are all tapered. This tapered design makes it easier to remove the molding pin during manufacturing. A taper angle, also referred to as a draft angle, between 0.5 and 3 degrees is particularly effective in allowing the molding pin to be removed. Preferably, the taper angle (or draft angle) is 1 degree.

[0136] It is particularly advantageous to provide one or more tapered fluid flow transmission channels 2026 in the valve stem 2004. This shape is not only convenient for easier molding (as just discussed), but also provides excellent fluid flow and actuation dynamics. This is because each end of the tapered channel 2026 has a different diameter. For example, when the fluid enters the top of the metering chamber 2034a / b of the valve 2004, the fluid enters the channel 2026 via a relatively large (wide) diameter port and leaves the channel 2026 via a relatively small (thin) diameter port. Through the Venturi effect, this diameter change causes the fluid velocity to increase. This speed change is also accompanied by a reduction in the static pressure of the metering chamber and an increase in the flow rate. Due to these changes in the fluid dynamics within the assembly, the valve chamber 2034a / b is refilled faster, and after actuation, the discharge element 2031 is pressed into its static (or filling) position faster. This allows the actuation of the valve assembly to be repeated more quickly. In one example, the diameter of the wider end of the fluid channel(s) 2026 is between 0.9 and 1.2 mm, while the diameter of the smaller end of the fluid channel(s) 2026 is between 0.4 and 0.6 mm. These dimensions result in particularly good fluid flow dynamics and fast reset / refill after actuation.

[0137] Similar advantages can be obtained by providing one or more tapered second fluid transfer channels 2028 in the head portion 2104 of the valve stem 2004. This ensures that the fluid is accelerated when entering the outlet conduit 2025, thereby quickly emptying the valve and making the fluid flow well atomized. In one example, the diameter of the wider end of the second fluid channel (one or more) 2028 is between 0.2 and 0.7 mm, while the diameter of the smaller end of the second fluid channel (one or more) 2028 is between 0.1 and 0.3 mm. These dimensions result in particularly good fluid flow dynamics and fast actuation potential.

[0138] Advantageously, the present assembly 4003 is able to precisely determine and modify the metered dose discharged by the discharge assembly by modifying the length of the upright tubular socket 2102. The socket 2102 surrounds the housing liquid inlet 2011 and extends upward into the interior of the housing, thereby defining the volume left for the fluid. By changing the size of the upright socket 2102 (e.g., during molding), the discharge assembly can be configured to discharge a specific metered volume, preferably between 30 microliters and 150 microliters. The height of the socket can be easily modified without further modification of the outer housing. This makes it easier to manufacture discharge assemblies suitable for different tasks.

[0139] To facilitate understanding of the improved exhaust assembly 4003, Figures 10 to 12 An exemplary arrangement of upper housing portion 2007a is shown in greater detail. Fig.10 A side view of the upper housing portion 2007a is shown. Fig.11 Shown with Fig.10 The fins 3100 are clearly visible, as are the protrusions 3300 for forming an interference fit with the bottom housing portion 2007b. Fig.12 A perspective view is shown.

[0140] Similarly, Figures 13 to 15 An exemplary arrangement of lower housing portion 2007b is shown. Fig.13 A side view of the lower housing portion 2007b is shown. Fig.14 Shown with Fig.13 The sectional view corresponding to the AA view in FIG. The groove 3400 and the recess 3500 for forming an interference fit with the top housing portion 2007a are clearly visible. Fig.15 A perspective view is shown.

[0141] Refilling of the improved assembly 4003 can be performed in any of the ways described above in conjunction with Figures 1A to 2C. In particular, the valve stem 2004 can be depressed and then the refill fluid can flow down the outlet 2025, out of the second fluid flow channel 2028, into the fluid flow channel 2026, around the discharge element 2031, into the socket 2102 via the groove 2112, and out of the inlet 2011 into the container to which the assembly 4003 is attached. Alternatively, a single-use device can be provided. In this case, the valve assembly 4003 is placed in the appropriate position on the pre-pressurized container and then crimped (or riveted) into place with the mounting cup 3200. In the case of single use, there is no need to provide a refill mechanism.

[0142] Device of the present invention can be used as aerosol spray equipment.Such equipment can be used for conveying various materials, preferably dissolved or dispersed in water.For example, the liquid in the container can comprise a series of materials selected from medicine, agricultural chemicals, spices, air fresheners, odor neutralizers, disinfectants, depilatory chemicals (such as calcium thioglycolate), depilatory chemicals, cosmetics, deodorants, antiperspirants, antibacterial agents, antiallergic compounds and two or more mixtures thereof.In addition, the container can comprise a foamable composition, optionally comprising any material disclosed above.Alternatively, the water in the container can comprise one or more organic solvents or dispersants to help the material dissolve or disperse in water.

[0143] The device of the present invention can be used with a device having a dispensing mechanism that opens and closes periodically. This can be automatic.

[0144] For example, the device of the present invention may be used to provide an air treatment agent to an air treatment device comprising: an airborne agent detector comprising one or more airborne agent sensors, wherein the airborne agent detector comprises means for detecting a threshold level or concentration of an airborne agent; means for mounting the device of the present invention (including the pressurized container if present) to the device; and means for discharging a portion of the air treatment agent from the device of the present invention when the detector detects the airborne agent. For example, such an air treatment device (not including the device of the present invention) is disclosed in WO2005 / 018690. Alternatively, the device of the present invention may be used to dispense a composition from a spray device as disclosed in WO 2007 / 045826.

[0145] The material used to form the liquid discharge element 2031 may be any suitable material. Preferably, the liquid discharge element comprises or consists of a thermoplastic elastomer, more preferably a vulcanized thermoplastic rubber. is a suitable exemplary material. The inventors have identified that these materials produce particularly good seals between the liquid discharge element and the sealing surface in the valve stem. Steel is also a suitable material and is generally less expensive than thermoplastic elastomers.

[0146] Preferably, the liquid discharging element has a Shore hardness of 40 to 70, measured on the Shore D durometer. This is again determined to provide a robust liquid discharging element that is hard enough to withstand long term use without degradation, while still being soft enough to seal properly and form a good fit against the sealing surface of the valve stem.

[0147] Preferably, the liquid discharge element weighs at least 0.03 g to ensure that the liquid discharge element reliably sinks under gravity after discharging the metered volume. The liquid discharge element may comprise more than one material, for example a first portion of a first material combined or connected to a second portion of a second material. In an advantageous embodiment, the first portion of the liquid discharge element is formed of a thermoplastic elastomer to provide a good seal against the sealing surface of the valve stem, and the second portion of the liquid discharge element is formed of a heavier material, such as steel, to provide sufficient weight so that the liquid discharge element sinks under gravity after actuation. The first and second portions may be integral and / or form a first end and a second end of the liquid discharge portion.

Claims

1. A discharge assembly for discharging a metered volume of liquid held in a pressurized or pressurizable container, the assembly comprising: (i) a housing having a liquid inlet at a first end thereof, (ii) a valve stem having a body located within the housing and having a head portion projecting from a second end of the housing, the valve stem being axially movable relative to the housing between a first extreme position in which the assembly is closed to liquid discharge and a second extreme position for discharging the metered volume, (iii) a chamber disposed within the body of the valve stem and having a liquid inlet toward a first end of the chamber and a first fluid transfer passage toward an opposite second end of the chamber, the first fluid transfer passage providing communication between the chamber and an exterior of the valve stem, and (iv) a liquid discharge element movable along the chamber from a liquid filling position to a liquid discharge position to effect discharge of the metered volume of liquid, Wherein, the outer portion of the valve stem and the inner portion of the housing are configured such that: (a) in a first extreme position of the valve stem, a second fluid transfer passage exists along the outer side of the valve stem between the inlet of the housing and the first fluid transfer passage, and (b) In the second extreme position of the valve stem, the fin forms a temporary interference seal between the interior of the housing and the exterior of the valve stem, thereby closing the second fluid transmission passage to prevent fluid flow.

2. The discharge assembly according to claim 1, characterized in that The fin is disposed in the interior of the housing.

3. The discharge assembly according to claim 2, characterized in that The fins are integral with the interior of the housing.

4. A discharge assembly according to any preceding claim, characterised in that Also included is a seat portion configured to interface with the fin to provide the interference seal when the valve stem is in the second extreme position.

5. The exhaust assembly according to claim 4, characterized in that The seat includes a chamfered surface.

6. The discharge assembly according to claim 4 or 5, characterized in that: The fin extends at least 0.1 mm, preferably between 0.1 mm and 0.2 mm, inclusive, into the path of the seat.

7. A discharge assembly according to any preceding claim, characterised in that The length of the temporary interference seal is between 0.2 mm and 3 mm, preferably between 1 mm and 2 mm.

8. A discharge assembly according to any preceding claim, characterised in that The housing (2007) comprises a top housing portion and a bottom housing portion.

9. The exhaust assembly according to claim 8, characterized in that The top housing portion is configured to attach to a mounting cup.

10. The discharge assembly according to claim 8 or 9, characterized in that The top housing portion and the bottom housing portion are joined by a permanent interference fit.

11. The exhaust assembly according to claim 10, characterized in that The permanent interference fit is configured to withstand an applied force of 100N.

12. The discharge assembly according to any one of claims 8 to 11, characterized in that The bottom housing portion includes a channel configured to receive the top housing portion.

13. The exhaust assembly according to claim 12, characterized in that The channel further comprises a recess configured to receive a corresponding protrusion on the top housing portion and / or wherein the channel further comprises a protrusion configured to interface with a corresponding recess on the top housing portion.

14. The discharge assembly according to any one of claims 8 to 13, characterized in that The bottom housing portion includes a base portion having a thickness of no more than 2 mm.

15. A discharge assembly according to any preceding claim, characterised in that The discharge assembly has a stroke length of at least 2 mm.

16. The discharge assembly according to any one of claims 8 to 15, characterized in that At least one of the following volumes is tapered: the chamber, the chamber being disposed within the body of the valve stem; the interior volume of the top housing portion; the interior volume of the bottom housing portion; and The first fluid delivery channel.

17. A discharge assembly according to any preceding claim, characterised in that When in the liquid discharging position, the liquid discharging element abuts a sealing surface disposed within the valve stem chamber.

18. The exhaust assembly according to claim 17, characterized in that The sealing surface comprises an O-ring or a gasket against which the liquid discharging element can abut.

19. The discharge assembly according to claim 17 or 18, characterized in that The sealing surface is chamfered at an angle relative to the longitudinal axis of the valve stem, wherein the angle is preferably between 120 and 180 degrees, more preferably between 120 and 160 degrees.

20. The discharge assembly according to claim 17 or 18, characterized in that The sealing surface is a curved surface. Optionally, the curved surface is: a convex surface, preferably having a radius of 1.5 to 1.8 mm at the point of maximum curvature; or The concave surface, in which the liquid discharge element is receivable, preferably defines an angle of 30 degrees at its lowest point relative to the longitudinal axis of the valve stem.

21. A discharge assembly according to any preceding claim, characterised in that The liquid discharge element is movable from its liquid discharge position to its liquid filling position by a return force, optionally wherein the liquid discharge element has negative buoyancy in the liquid to be dispensed to provide at least a part of the return force.

22. A discharge assembly according to any preceding claim, characterised in that The liquid discharge element is spherical.

23. A discharge assembly according to any preceding claim, characterised in that The head portion of the valve stem protruding from the second end of the housing is movable in an annular seal disposed at the second end of the housing, and the head portion has a third fluid transmission channel connected to an outlet of the head portion, the third transmission channel being closed to fluid flow at the first extreme position of the valve stem and open to fluid flow at the second extreme position thereof.

24. A discharge assembly according to any preceding claim, characterised in that The inlet of the housing is coaxial with the valve stem chamber.

25. A discharge assembly according to any preceding claim, characterised in that The bottom shell portion includes an upstanding tubular socket that surrounds the inlet and projects upwardly into the interior of the shell, optionally wherein the upstanding tubular socket is sized such that the discharge assembly is configured to discharge a metered volume between 30 microliters and 150 microliters.

26. A liquid dispensing device provided with a discharge assembly as claimed in any preceding claim for discharging a metered volume of liquid held in a pressurised or pressurisable container of the liquid dispensing device.

27. The liquid dispensing device according to claim 26, characterized in that: The container is pressurized with nitrogen, air, liquefied natural gas, liquefied hydrocarbon gas or carbon dioxide; and / or The device is an aerosol spray device; and / or The device comprises a compound or composition comprising a material selected from the group consisting of pharmaceuticals, agricultural chemicals, fragrances, air fresheners, odor neutralizers, disinfectants, polishes, insecticides, depilatory chemicals (such as calcium thioglycolate), depilatory chemicals, cosmetic agents, deodorants, antiperspirants, antibacterial agents, antiallergic compounds, and mixtures of two or more thereof.

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