Device For Dispensing Fluids

Abstract

A device for dispensing fluid from an aerosol container of the kind which meters discrete doses, operable to dispense the dose when suction is applied. The preferred form of the device has a recess to hold the aerosol with the outlet of the aerosol sealingly secured in a cavity, and a resilient element to seal the outlet from the cavity, which opens into an air duct. The resilient element is held against the cavity outlet by a spring-loaded pivoted arm, and a vane on the arm is located in the air duct, so that suction applied at the outlet of the duct will cause the vane to pivot the arm and release the element. In use, the aerosol is operated to meter a dose, which is held partly in the aerosol outlet and partly in the cavity until suction applied at the outlet of the duct causes the cavity to be opened and the dose dispensed into the duct.

Description

BACKGROUND OF THE INVENTION

The invention relates to devices for dispensing fluids, and more particularly to devices for dispensing fluid from aerosol containers of the kind which, in action, discharge through a spray stem or other spray head. Such aerosol containers are hereinafter referred to as aerosol containers of the kind described.

DESCRIPTION OF THE PRIOR ART

The use of aerosols for the relief of ailments such as asthma and bronchitis has been known for many years. It is however important that the user receives a dose of the drug from the aerosol at the commencement of inhalation of the breath to ensure that the fine particles penetrate into the smallest airways in the lungs.

Apparatus has been devised in which the user must suck at a mouthpiece and then actuate the aerosol, the user not being able to draw any breath until the aerosol is actuated. This is undesirable as many users have difficulty drawing breath even under normal circumstances.

In other known devices the user first cocks a spring on the device and then draws a breath through the device. The spring is triggered by a breath controlled valve and the energy stored in the spring is utilised to actuate the aerosol. However these devices are complicated in construction and therefore expensive. Furthermore as considerable force is required to actuate the aerosol the dose is not always released right at the start of drawing breath.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a device for dispensing fluid from an aerosol container which device is of very simple and inexpensive construction, being composed of only a small number of moving parts.

It is a further object of the invention to provide such a device in which a dose of fluid may readily be provided when suction is applied to the device.

In general terms these objects are achieved by producing a device in which a dose may first be released from the aerosol and stored, subsequent application of suction opening a valve mechanism to release the dose. The valve mechanism may conveniently be designed to operate under the influence of very low forces.

Accordingly the invention provides a device for dispensing fluid from an aerosol container of the kind described comprising a duct having an inlet and an outlet, means to receive the spray head of the aerosol in sealing engagement therewith so that on actuation of the aerosol a discrete dose of fluid is stored at least partially in the spray head, a flow sensor arranged in the duct and a valve connected to the flow sensor such that when the pressure at the outlet of the duct falls below the pressure on the inlet side by a predetermined amount the valve connects the said receiving means to the duct so that the dose of fluid is free to pass into the duct.

It is preferred that the dose is stored partly in the spray head and partly in the receiving means.

The aerosol may be of the kind in which movement of the aerosol body toward the spray head causes a dose of fluid to be ejected into the spray head.

Alternatively the aerosol may be of the kind in which movement of the aerosol body towards the spray head causes a dose of fluid to be prepared for ejection into the spray head and return movement of the aerosol away from the spray head causes ejection of the dose. As a further alternative the aerosol may be of the kind in which movement of the aerosol body towards the spray head causes continuous flow of fluid into the spray head. To eject a discrete dose with either of these two alternative aerosols it is necessary to move the aerosol body towards the spray head and then away from the spray head. When the device is for use with either of these two alternative aerosols the device may include means to prevent connection of the duct to the receiving means until the discrete dose has been ejected into the spray head.

The flow sensor preferably comprises a movable vane mounted in the duct.

The valve member may comprise a resilient member urgeable against an aperture in the receiving means which aperture leads to a port in the duct.

Preferably the vane is pivotally mounted and the valve member is arranged on a lever rigidly mounted on the vane.

The valve may be spring urged against the said aperture (e.g., by a spring connected to the vane). Alternatively means may be provided to urge the valve against the aperture just before fluid is ejected into the spray head, the flow sensor acting to release said means.

In the case where the valve is biased to the closed position, the device may include means for relieving the seating pressure of the valve when the device is not in use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in section of one example of an inhaling device according to the invention;

FIG. 2 is a sectional view of one alternative form of device, and

FIG. 3 is a sectional view of another alternative device.

DESCRIPTION OF EXAMPLES OF THE INVENTION

Referring to FIG. 1, an inhaling device for dispensing medicament to, for instance, asthma sufferers comprises a plastics casing 11 having an outlet orifice 12 of a suitable size and shape for insertion into the mouth of a user. The casing 11 defines a recess 13 in which there is placed an aerosol-type medicament dispenser 14. The dispenser 14 is of a known type, and incorporates a metering valve 15 having a spray stem 16, which valve operates to eject into the stem 16 a predetermined amount of medicament when the dispenser 14 is pressed downwards while the stem 16 is supported against movement. The stem is received sealingly in socket 18.

Also fitted within casing 11 is a control assembly comprising a body 17, vane 31, lever 26 and socket 19. The socket 19 and body 17 are rigidly interconnected and lever 26, which is integral with vane 31, is pivotally mounted in the body 17 by means of a saddle 26a which straddles a flange 26b.

Socket 19 receives socket 18 and in the cavity between the two sockets there is arranged a resilient valve disc 22. Socket 19 has an outlet port 21. Valve member 22 is movable towards the socket 18 to seal an outlet 18a in the lower end thereof. An operating rod 23 mounted on the end of lever 26 passes through a bore 24 in socket 19 and engages the valve disc.

The control assembly lies partially within an air duct 28 leading from a set of inlet holes (not shown) at 29 on one side of vane 31 and down the other side to the outlet orifice 12. The air vane 31 and the lever 26 are so dimensioned that air entering by the inlet holes 29 must pass up on one side of the vane, over the top of the vane and down past the sockets 18 and 19 to reach the outlet orifice 12. A spring 30 connects the lever to the casing 11, and biases it in a counter clockwise direction. As a result of such biasing, the rod 23 is moved upwards and holds the valve member 22 against the socket 18 to seal it, while the air vane 31 is moved to a position in which it effectively closes duct 28 completely. A dust cap 32 is provided, which may be fitted over the outlet orifice 12, and the dust cap includes a tongue 33 engageable with an extension 34 on the lever 26 to move it downwardly, thus releasing the pressure on the valve member 22 when the device is not in use. The dust cap has a further tongue 32a to close the inlet holes.

In use of the device, the asthma sufferer inserts the outlet orifice 12 into his mouth, depresses the dispenser 14, and draws a breath. Depression of the dispenser 14 makes available partly in the stem 16 and partly in socket 18 a dose of medicament, but because the valve member 22 is held against the socket 18 by the rod 23, this dose is held back. When the user draws breath, however, a partial vacuum is created in the region of the valve member, with the result that the air pressure on the side of the vane 31 in communication with the inlet holes moves the vane, and thus the lever 26, in a clockwise direction, allowing air to flow past the vane. As the lever 26 moves the valve member 22 is withdrawn from the socket 18, so that the air flowing past the valve assembly entrains the dose of medicament which passes from the stem 16 and socket 18 into the duct. Thus it will be seen that by the use of this device the asthma sufferer receives the dose of medicament at the very beginning of the intake of breath, thus ensuring that the medicament penetrates into the smallest airways in the lungs.

Two alternative forms of device are shown in FIGS. 2 and 3, in which like parts have been given like reference numerals. In both these devices, the valve member 22 is not moved into the sealing position until the moment at which the device is used. Referring first to FIG. 2, the stem 16 of the dispenser 14 is fixed relative to the casing 11 and protrudes into the socket 19. The operating rod 23 of the valve assembly is mounted on a lever 35 pivoted to the casing 11 and is biased away from the valve assembly by a spring 36 connected to the lever 35. On the other end of the lever 35 is a trigger arm 37 engageable by a projection 38 connected to the air vane 31 (which is here pivoted on the casing 11). A further lever 39 is mounted on the casing 11 and is biased in a clockwise direction by a spring 41. One end of the lever 39 is connected by a push rod 42 to the dispenser 14, while the other end is engageable under a step in the trigger arm 37.

In the use of the device, the air vane 31 is initially in the position shown, blocking the inlet 29. The dispenser 14 is depressed to dispense a dose of medicament and as it is depressed the push rod 42 rotates the lever 39 counter clockwise, so that the outer end of the lever lifts the trigger arm 37 and the lever 35 and thus raises the push rod, moving the valve member upwards to seal the stem 16 before the dose is actually dispensed. Thus, depression of the dispenser 14 makes the dose available, under pressure, in the stem 16. When the user of the device then sucks at the outlet orifice 12, the partial vacuum within the air duct 28 results in the vane 31 rotating in a counter clockwise direction so that the projection 38 engages the top of the trigger arm and moves it away from the lever 39. The lever 35 then drops under the influence of spring 36, aided by the pressure of the medicament on the valve member 22, and the medicament is then dispensed into the air stream from the valve stem 16. When the dispenser 14 is released after breath has been drawn, a reset arm 43, rigidly connected to the lever 39, moves the vane 31 back to its start position.

Referring now to FIG. 3, in this embodiment a lever 44 is used to operate dispenser 14; at the end of the lever 44 a vertically moving slide 45 is arranged, which is engageable with a projection 46 on the trigger arm 37. An interlock 47 between the vane 31 and the trigger arm 37 allows relative vertical movement of the arm and vane but ensures that counter clockwise rotation of the vane causes the trigger arm to move to the left, away from the slide 45. The operating rod 23, the lever 35, the spring 36 and the trigger arm are arranged in a similar manner to that shown in FIG. 2, except that the fulcrum is positioned between the operating rod and the trigger arm rather than at one end of the lever.

In use of the device shown in FIG. 3, the lever 44 is depressed, thus depressing the dispenser 14 to release a dose of medicament and at the same time depressing the trigger arm 37 via the slide 45 and the projection 46. This causes the lever 35 to rotate in a clockwise direction pushing the operating rod 23 and therefore the valve member 22 upwards to seal the dose dispensed in the stem 16 as in the other embodiments described. When the user draws breath through the orifice 12, the vane 31 is rotated counter clockwise and draws the projection 46 away from the slide 45, and when they disengage the spring 36 causes the valve assembly to dispense the dose available in the stem 16, the operating rod 23 being moved downwards. This arrangement has certain advantages, from a mechanical point of view, as the distances moved by the parts involved are increased, thus allowing greater manufacturing tolerances. Furthermore, the force required to operate the device is reduced by the use of the lever 44.

Generally, the invention provides a device by which the user can obtain the dose of medicament at the correct point in his drawing in of breath, and this is achieved in an arrangement in which the forces required are very low and the parts are not stressed except over the very short period of use. Previous devices have consisted of an arrangement in which an air vane is linked to the dispenser, it being necessary for the patient to suck at the orifice before, and during, depression of the dispenser. The air vane is held in a closed position until such time as the dispenser is operated, so that the patient obtains no air at all until such time as he operates the dispenser, and clearly this is undesirable for asthma sufferers who are in any case short of breath. In other devices, the drawing of breath by the patient triggers an arrangement which operates the metering valve directly, utilising the energy stored in a spring to overcome the considerable resistance (about 5 lbs) of the metering device. The present invention, on the other hand, utilises a two stage action in which the fluid is dispensed and stored by hand pressure on the dispenser and is released by an air vane arrangement on drawing breath, which release requires very little pressure.

The invention includes a miniature version of the present device operated by a battery. In this version there is no obstruction to the flow of air, but the commencement of flow is sensed by a "Pirani" type of gauge in a bridge circuit (e.g., a hot wire anemometer), and a tiny solenoid is switched to release the dose.

The above examples of devices may be utilised with the alternative aerosols described although it may be desirable to provide means which prevent operation of the valve member 22 after the dispenser has been pressed downwardly until the dispenser is released. This would ensure that the user receives a single discrete dose at the start of drawing breath. For instance means may be provided to lock the vane 31 in the position shown in FIG. 1 (i.e., the sealing position) when the dispenser 14 is in the depressed position.

Although the invention has been described with particular reference to devices for dispensing medicament to asthma sufferers, it will be clear that the general principles of the invention may be extended to a far wider field.

Claims

I claim:

1. An aerosol device comprising a housing in which is located an aerosol container of the type which has a tubular valve stem which is depressable against a spring means and internal valve means which is opened when the valve stem is depressed to deliver a discrete metered dose of fluid through the stem and is closed when the stem is released, said housing having receiving means for said container which makes sealing engagement with said stem of said container, and which resists movement of said stem away from said container, a duct in fluid connection with said receiving means, one end of said duct being open to the atmosphere and the other end thereof being arranged for insertion into the mouth of a user, a second valve means disposed exterior of said tubular valve stem to prevent flow of said metered dose from said stem into said duct after the stem has been depressed, a flow sensor arranged in said duct, and means to release said second valve means to allow said dose to flow into said duct when said flow sensor detects a flow of air in the duct caused by a user inhaling through the duct.

2. A device as claimed in claim 1 in which said receiving means comprises a chamber and wherein said dose may be stored partly in said chamber.

3. A device as claimed in claim 2 in which said second valve means comprises a resilient member urgeable against an aperture in said receiving means which aperture leads to a port in said duct.

4. A device as claimed in claim 3 including means to urge said second valve means against said aperture just before fluid is ejected into the receiving means, said flow sensor acting to release said means.

5. A device as claimed in claim 3 in which said second valve means is spring urged against said aperture.

6. A device as claimed in claim 5, further including means for releasing said second valve means when the device is not in use.

7. A device as claimed in claim 1 in which said second valve means makes a sealing engagement directly with said stem.

8. A device as claimed in claim 1 wherein said aerosol container is movably mounted in said housing and wherein movement of said aerosol container to depress said valve stem renders said second valve means inoperative to connect said stem and said duct.

9. A device as claimed in claim 1 in which said flow sensor comprises a movable vane mounted in said duct.

10. A device as claimed in claim 9 in which said vane is pivotally mounted and said valve means is arranged on a lever rigidly connected to the vane.

11. A device as claimed in claim 10 in which said vane pivots about a hinge between said lever and the end of said duct arranged for insertion into the mouth of the user, said hinge being adjacent said second valve means.

12. A device for dispensing fluid from an aerosol container of the kind described comprising: an elongate housing having two parallel longitudinal chambers therein each having an end access opening, the two openings being at opposite ends of the housing respectively; one chamber being arranged to receive through the access opening the aerosol container, spray head first, and having a socket in the end of the chamber opposite the access opening to sealingly receive the spray head, there being in the base of the socket an outlet aperture for fluid; a base plate; an elongate vane mounted on the plate so as to be pivotable on the plate, about an axis parallel to the plate, the plate having at least one inlet aperture therein on one side of the vane and being connected or connectible to the housing with the vane extending into the other chamber to define a duct which passes from the said inlet aperture up the said one side of the vane, over the top of the vane, down the other side of the vane and past the said outlet aperture of the socket; a lever integral with the vane and carrying a resilient valve member; and a spring urging the vane into a position in which the lever presses the valve member against the said outlet aperture to seal the aperture; the arrangement being such that when an aerosol is inserted into the said one chamber, spray head first, and is then actuated, a dose of fluid from the aerosol is stored partly in the spray head and partly in the socket, and when suction is subsequently applied to the end of the duct remote from the inlet aperture, air flow along the duct moves the vane into a position to release the valve member so that the dose of fluid is released into the air flow through the said outlet aperture.

13. A device as claimed in claim 12 including a dust cap mountable in the housing to close both ends of the duct, the cap having a member arranged to move the lever and vane to the position in which the valve member is released, so that when the device is not in use the pressure on the socket exerted by the valve member is relieved.