Valve assemblies

A valve assembly for a pressurized aerosol container which has a neutral bias. The valve may be of the metered dose type and is preferably springless. Containers equipped with such valves may be employed in breath actuated dispensing devices with simplified mechanisms since it is not necessary to overcome any biasing force within the valve.

FIELD OF THE INVENTION 
This invention relates to valve assemblies for pressurised fluid containers 
such as aerosol containers and in particular to valve assemblies capable 
of dispensing metered-doses of the contents of an aerosol container. 
BACKGROUND 
Pressurised fluid containers are in widespread use for dispensing a wide 
variety of materials including cosmetic materials, e.g., deodorants, body 
fresheners etc., and domestic cleaning materials, e.g., detergents, 
polishes, waxes etc. Conventional pressurised fluid containers are 
provided with a valve assembly for dispensing the container contents 
comprising a hollow, elongate valve member which is movable relative to 
the body of the container between an outer closed position and an inner 
dispensing position. The valve member is biased, usually by a spring, to 
the outer closed position to prevent the discharge of material from the 
container when not in use. To actuate the valve assembly, the valve member 
is depressed inwardly by the user to the dispensing position allowing 
material to exit from the container. 
The use of aerosol devices to administer medicament, such as drugs or other 
therapeutically active compounds, by inhalation therapy is commonplace, 
particularly for the treatment of respiratory disorders, such as asthma, 
where it is important that the amount of material dispensed is a 
predetermined, accurate volume each time the valve is actuated. The 
aerosol container is charged with a self-propelling liquid composition 
containing the medicament dissolved or dispersed therein and provided with 
a valve assembly capable of dispensing metered amounts of the composition. 
Examples of such valve assemblies are disclosed in British Patent Nos. 
864694, 1287126, 1336379, 2004526, 2077229 and 2086845, European Patent 
No. 191614 and U.S. Pat. Nos. 2,746,796 and 3,738,542. 
Many known metering valve assemblies for pressurised aerosol containers 
comprise a metering chamber positioned at the outlet of the container 
which is filled with a fresh dose of the material to be dispensed 
immediately after the previous dose has been dispensed. This feature is 
incorporated into the valve assembly to avoid the need to prime the 
assembly before use. A hollow elongate valve member is arranged for 
reciprocal movement through the metering chamber between a closed, 
non-dispensing position where the metering chamber is filled with the 
material to be dispensed and a dispensing position, in which the metered 
dose of material is dispensed through the valve member to the outside 
environment. The valve member is again biased to the closed, 
non-dispensing position. This arrangement allows the dosage of material 
dispensed from the aerosol container to be accurately reproduced with each 
operation of the valve. 
In such prior art valve assemblies described above, the elongate valve 
member is biased to its closed, non-dispensing position, normally under 
the influence of a spring. Generally, a force must be applied to the valve 
member to overcome the spring and move the valve member to its dispensing 
position. There may be certain disadvantages to this arrangement of valve 
assembly, particularly when fitted to aerosol containers for use with 
certain types of inhalation devices for dispensing medicament to patients 
in inhalation therapy. 
U.S. Pat. No. 4,506,803 discloses a valve assembly for dispensing metered 
amounts of material from a main reservoir. The valve assembly includes a 
metering chamber having a pair of apertures that respectively connect the 
metering chamber to the main reservoir and to the exterior. A valve seal 
is mounted within each of the apertures. An additional seal is mounted 
within the metering chamber, with all the seals in substantial alignment. 
A slidable valve member comprising dispensing and bypass passages is 
positioned within and co-operable with the seals. The bypass passage 
selectively interconnects the main reservoir with the metering chamber and 
the dispensing passage interconnects the metering chamber with the 
exterior. The seals selectively co-operate with the two passages as the 
stem is slidably moved through the metering chamber and the reservoir. 
The valve member is biased to a non-dispensing position, in which the 
dispensing passage is sealingly engaged by one of the chamber seals, by a 
spring mounted exteriorly of the container so that the bypass passage is 
positioned within the unfilled metering chamber. The metering chamber is 
isolated from both the main reservoir and from the exterior of the 
assembly. The valve member is then depressed inwardly to a charging 
position in which the inlet aperture of the dispensing passage is 
sealingly engaged by the additional seal mounted within the metering 
chamber. Accordingly, the metering chamber and the exterior of the 
apparatus are isolated. In this position a portion of the bypass passage 
is moved into the main reservoir, thereby placing the main reservoir and 
the metering chamber in communication via the bypass passage. This charges 
the metering chamber with a desired amount of fluid material to be 
dispensed. The valve member is then released so that it will slide into a 
dispensing position in which the main reservoir and metering chamber are 
again isolated from one another; the bypass passage moving into sealing 
engagement with the other valve seal and back into the metering chamber. 
During this movement of the stem, the inlet aperture of the dispensing 
passage first moves out of engagement with the additional seal and then 
into the metering chamber, whereby material from the metering chamber 
enters the dispensing passage inlet port, moves through the dispensing 
passage, and is dispensed through a spray nozzle of the dispensing 
passage. As the valve member continues to be biased exteriorly, the nozzle 
continues to dispense a pre-determined amount of the material held within 
the metering chamber until the dispensing passage inlet port again moves 
into engagement with the first seal and the assembly again assumes the 
non-dispensing position. 
European Patent Application No. 0260067 discloses a metering valve for a 
pressurised aerosol container which is configured such that the metering 
chamber exists only upon actuation of the valve stem to dispense the 
dosage. Thus, the metering chamber is created, filled with aerosol 
formulation and emptied during the brief moment the valve stem is 
depressed and subsequently released by the user to dispense a dose. The 
valve is biased to its non-dispensing position. 
Valves which are biased to the dispensing position are known and are 
disclosed, for example in GB 1200129, 1246710, 1310161, 1311512, 1370885 
and 2240930. 
SUMMARY OF THE INVENTION 
The present invention seeks to provide a new arrangement of valve assembly 
for pressurised fluid containers and in particular for pressurised aerosol 
containers. 
According to the present invention there is provided a valve assembly for a 
pressurised aerosol container in which the valve assembly has a neutral 
bias. Preferably, the valve assembly is of the metered-dose type. 
The valve assemblies of the invention have no net mechanical bias to the 
dispensing or non-dispensing positions. Preferably the valves are 
springless. The valve may be provided with means to latch the valve in its 
closed position. Such neutral biased valves are preferably used in 
combination with dispensing apparatus incorporating a valve actuation 
mechanism. The valve actuation mechanism may include biasing means to bias 
the valve to its open or closed position. Only low bias is required as 
there is no internal spring in the valve which must be overcome by the 
valve actuation mechanism. Thus there is little strain on the valve 
actuation components. 
The valve assemblies of the invention may have a wide variety of 
configurations. 
In one embodiment of the present invention there is provided a valve 
assembly for a pressurised aerosol container, which valve assembly 
comprises: 
a casing adapted to be secured to an aerosol container; 
a hollow body secured to the casing and defining a metering chamber having 
a first opening communicating with the outside environment and a second 
opening communicating with the interior of the aerosol container; 
an elongate valve member sealingly extending through an aperture in the 
casing and at least the first opening of the metering chamber, which 
elongate valve member is reciprocally movable between a dispensing 
position in which there is an open channel through the elongate valve 
member connecting the metering chamber with the outside environment while 
the metering chamber is sealed to prevent the passage of material from the 
interior of the aerosol container to the metering chamber and a closed, 
non-dispensing position in which the elongate valve member allows the 
passage of material from the interior of the aerosol container to the 
metering chamber but prevents the passage of material from the metering 
chamber to the outside environment, the valve member not being biased to 
the dispensing or non-dispensing position. 
In a further embodiment, the valve assembly comprises a casing adapted to 
be secured to an aerosol container defining a formulation chamber, the 
hollow body defining a metering chamber having a first opening 
communicating with the outside environment and a second opening 
communicating with the formulation chamber. The elongate valve member 
comprises an outlet channel communicating with the outside environment and 
an inlet channel, and is unbiased and reciprocally moveable between: 
(i) a dispensing position, in which the outlet channel also communicates 
with the metering chamber, and in which the valve member is in sealing 
engagement with the second opening of the metering chamber to prevent the 
passage of formulation from the formulation chamber to the metering 
chamber, and 
(ii) a closed, non-dispensing position, in which the inlet channel of the 
valve member is in open communication with the formulation chamber and the 
metering chamber, thereby allowing the passage of formulation from the 
formulation chamber to the metering chamber, and in which the valve member 
is in sealing engagement with the first opening in the metering chamber, 
thereby preventing the passage of formulation from the metering chamber to 
the outside environment. 
In a further embodiment the valve assembly is configured such that the 
metering chamber only exists upon actuation of the valve stem to dispense 
the dosage, the valve stem being unbiased. Such valves may have a similar 
configuration to those disclosed in EP-A-0260067 with suitable 
modification to remove the biasing means. 
According to another aspect of the present invention there is provided a 
pressurised aerosol container comprising an outlet having a valve assembly 
as described above for dispensing the material contained therein. Although 
the valve assemblies may be fitted to most pressurised fluid containers, 
they are particularly suitable for use with aerosol containers for 
dispensing medicament in inhalation therapy. 
Aerosol containers fitted with a valve assembly of the invention are 
generally intended to be used in the inverted position, i.e., with the 
valve assembly held lowermost, for efficient dispensing of the contents 
held therein. However, the valve assemblies may also be modified for use 
in an upright position, e.g., by the provision of a dip tube. 
Inhalation therapy is an increasingly important method of administering 
medicaments to a patient. The medicament is formulated into a suitable 
composition and charged in aerosol container with a suitable propellant. 
The aerosol container is inserted into an inhalation device comprising a 
housing adapted to receive the container and a mouthpiece or a port 
adapted for nasal use through which the patient inhales. The medicament is 
administered by firing the inhaler, while simultaneously inhaling through 
the mouthpiece/nasal port. An example of such an inhalation device is 
commercially available from Minnesota Mining and Manufacturing Company 
under the trade mark "MEDIHALER". 
The inhaler may also include a breath-actuated mechanism which ensures 
synchronised dispensing of medicament with inspiration by the patient. An 
example of a breath-actuated inhaler is commercially available from 
Minnesota Mining and Manufacturing Company under the trade mark 
"AUTOHALER" and is disclosed, for example, in European Patent No. 147028. 
According to a further aspect of the invention there is provided a 
portable, hand-held inhaler for administering doses of medicament or other 
therapeutically active substance to a patient comprising a pressurised 
container of the invention. 
It is with the latter, breath-actuated type of inhalation device that 
aerosol containers fitted with a valve assembly in accordance with the 
invention are particularly suitable. Such breath-actuated inhalers 
generally comprising a housing having a mouthpiece and an air passage 
therethrough terminating at the mouthpiece, the housing being adapted to 
receive an aerosol container and having a support block with a socket 
adapted to receive the valve member of the aerosol container and a through 
orifice communicating between the socket and the air passage. The inhaler 
also includes latch means having parts movable between an engaged position 
in which movement of the container and the support block towards each 
other (upon the application of a force to bias the container and the 
support block towards each other) is prevented and a release position in 
which movement of the container and the support block towards each other 
(in response to the biasing force) is permitted causing the stem to move 
to its inner discharge position. The latch means typically comprises a 
vane mounted on the housing in the air passageway between the orifice and 
the mouthpiece for movement toward the mouthpiece under the influence of 
inhalation through the mouthpiece. When a patient inhales through the 
dispenser, the vane moves towards the mouthpiece from a blocking to a 
non-blocking position with respect to the passageway to release the latch 
means. 
Conventionally, such breath-actuated inhalers are primed by the patient 
displacing a cocking lever (typically the mouthpiece cover) immediately 
prior to their use to cause the container to move against a cocking 
spring. The cocking spring acts on the base of the aerosol container to 
urge the container towards the support block. As such, the design of the 
inhaler is confined somewhat by the need to displace the container 
relative to the valve member to prime the valve assembly and consequently 
by the length and overall shape of the container. Furthermore, a not 
inconsiderable force is required to overcome the biasing means to fire the 
inhaler. The valves of the invention have considerable benefits for 
breath-actuated systems, namely: 
1. Less force is required to displace the valve member, because there is no 
valve spring force to overcome. 
2. Less force is required to prime the inhaler and the mouthpiece cover may 
be used for this purpose. 
3. The inhaled effort required to trigger the breath actuation mechanism is 
less. 
4. The specifications on components can be more tolerant. 
5. A component is eliminated from the conventional valve, making the design 
simpler. 
Aerosol containers fitted with a valve assembly of the invention can also 
be used with other types of inhalation devices such as those incorporating 
pneumatic, hydraulic, mechanical, magnetic, electrical and 
electromechanical means for actuating or resetting the valve or blocking 
movement or priming actuation of the valve, e.g., as disclosed in our 
co-pending International Patent Publication Nos. WO92/07599 and 
WO92/07600. 
The elongate valve member generally comprises a discharge orifice through 
which material can be dispensed from the valve assembly, an outlet passage 
through which material can pass to the discharge orifice and a transfer 
port through which material can pass from the metering chamber to the 
outlet passage. The position of the transfer port on the valve member is 
arranged such that material from the metering chamber cannot pass through 
the transfer port in the non-dispensing position, thereby preventing its 
escape to the outside environment while charging the metering chamber. 
While the elongate valve member may be provided with a similar arrangement 
of orifice, inlet passage and transfer port to allow material to enter the 
metering chamber from the interior of the container in the non-dispensing 
position, the outer surface of the inner portion of the valve member may 
be provided with a filling channel which extends across the second outlet 
of the metering chamber in the non-dispensing position. 
Alternatively, the elongate valve member may be provided with a cutaway or 
constricted neck portion which extends through the opening of the metering 
chamber leading to the interior of the container when the valve member is 
in the closed, non-dispensing position. The relative dimensions of the 
cutaway/neck portion and the opening of the metering chamber are chosen 
such that the space defined therebetween allows material from the interior 
of the aerosol container to freely enter or leave the metering chamber 
without the flow of material being significantly impeded. In this modified 
valve, the contents of the aerosol container can, when the container is 
inverted and the valve member displaced to the non-dispensing position, 
flow freely into the metering chamber and any gas or vapour that may be in 
the metering chamber freely exit from the chamber. 
Alternatively, the elongate valve member may be completely disengaged from 
the opening of the metering chamber when the valve member is in the 
closed, non-dispensing position and the opening suitably dimensioned such 
that material from the interior of the container can freely enter or leave 
the metering chamber when the valve member is in the closed, 
non-dispensing position. 
In order to dispense, as near as possible, the entire contents of the 
aerosol container, thereby avoiding wastage of material, the valve 
assembly may be provided with a dipcup comprising a second hollow body 
retained upon and forming a shroud about the first hollow body defining 
the metering chamber, the shroud extending substantially to the casing and 
together with the metering chamber defining at least one passage through 
which material from the aerosol container may pass into the metering tank 
when the elongate valve member is in the closed, non-dispensing position. 
The valve assembly may comprise a pressure filling valve, to enable 
components of the formulation, maintained in liquid form under pressure, 
to be introduced under pressure into the aerosol container through the 
filling valve. 
The pressure filling valve may comprise an aperture in the metering chamber 
communicating with the aerosol container which aperture is adjacent to the 
casing and is covered by a sealing member which prevents the passage of 
material from the interior of the aerosol container to the metering 
chamber but allows passage of material from the interior of the metering 
chamber to the aerosol container when there is sufficient pressure 
difference between the metering chamber and aerosol container. To prevent 
permanent displacement of the sealing member from the aperture when 
filling the container, the valve assembly preferably comprises a shroud as 
defined above but shaped so as to cover the sealing member and to allow it 
limited movement, thereby facilitating pressure filling but preventing 
permanent displacement of the sealing member.

DETAILED DESCRIPTION 
Referring to FIG. 1, the valve assembly (1) comprises a casing (3) adapted 
to form the closure cap or ferrule of an aerosol container (not shown), a 
hollow body (5) which defines a metering chamber (7) having an opening at 
either end thereof (2 and 4) and an elongate, longitudinally reciprocable 
valve member (9) which extends centrally through an aperture (11) in the 
casing (3) and each opening (2 and 4) of the metering chamber (7). The 
innermost end of the valve member (9) sealingly extends through one 
opening (4) of the metering chamber (7) into the interior of the aerosol 
container when the valve assembly is fitted, e.g., by crimping, swaging, 
rolling etc., onto the container. The outermost end of the valve member 
(9) sealingly extends through the other outlet (2) of the metering chamber 
(7) and the aperture (11) of the casing (3) to the outside environment. 
Outer and inner sealing gaskets (13 and 15 respectively) are provided at 
each end of the hollow body (5) to prevent the escape of material from the 
metering chamber (7). A base member (17) is provided to secure the hollow 
body (5) in position. The valve assembly (1) is crimped over the neck of 
an aerosol container (not shown) with the provision of a sealing gasket 
(19) to provide a gas tight seal between the casing (3) and the container. 
The valve member (9) is movable between an outer non-dispensing position 
(shown in FIG. 2) and an inner dispensing position (shown in FIG. 3) and 
includes at its outermost end a discharge orifice (21) which communicates 
via an outlet passage (23) with a transfer port (25). The valve member (9) 
is arranged such that the transfer port (25) is disposed inside the 
metering chamber (7) when the valve member (9) is in the dispensing 
position, thereby allowing material to pass from the metering chamber (7) 
to the outside environment and outside of the casing (3) when the valve 
member (9) is in the non-dispensing position. The valve member (9) 
includes at its innermost end, on the outer surface thereof, a filling 
channel (27) which allows material contained in the aerosol container to 
enter the metering chamber (7) but only when the valve member (9) is in 
the closed, non-dispensing position. 
The outermost end of the valve member (9) is advantageously provided with 
an annular flange (35) to prevent the valve member (9) from being pulled 
into the valve assembly (1) and/or a gripping portion. The valve assembly 
(1) is optionally provided with a guiding shroud which in the embodiment 
shown comprises a plurality of longitudinal ribs (37). The guiding shroud 
clips into a complementary recess (39) in the base member (17) to ensure 
smooth movement of the valve member (9) and to act as a stop for inward 
movement of valve member (9). 
FIGS. 2 and 3 illustrate schematically the working stroke of a slightly 
modified valve assembly to that shown in FIG. 1. The base member (17) and 
guiding shroud have been omitted. The valve assembly (1) has also been 
inverted. 
Referring to FIG. 2, the metering chamber (7) is charged by outwardly 
displacing the valve member (9) in the direction indicated by the arrow 
marked `A` to the closed, non-dispensing position. This allows material 
from the container to enter and fill the metering chamber (7) via filling 
channel (27). The transfer port (25) is, in turn, positioned outside of 
the casing (3), thereby preventing the escape of material held in the 
metering chamber (7) to the outside environment. 
When a displacing force is applied to the valve member (9) it urges it in 
the direction indicated by the solid arrow marked `B` to the dispensing 
position. In this position, the transfer port (25) is located within the 
metering chamber (7) allowing the material held therein to exit through 
the outlet passage (23) to the discharge orifice (21). The filling groove 
(27) is, in turn, located entirely within the aerosol container, thereby 
sealing the metering chamber (7) against the entry of additional material 
until the next actuation of the valve assembly (1). 
Breath-actuated metered-dose inhalation devices of the type disclosed in 
European Patent No. 147028 but adapted for use with an aerosol container 
having a valve assembly in accordance with the invention are typically 
provided with a movable cover which is displaced by the patient to allow 
him or her access to the mouthpiece. The act of opening and closing the 
cover may conveniently be used to prime the inhalation device by effecting 
displacement of the body portion of the aerosol container. 
One such arrangement is shown in FIGS. 4 and 5 for an inhalation device 
(75) comprising a housing (77) adapted to receive an aerosol container and 
having a mouthpiece (79) and a cover (81) pivotally mounted at (83) which 
is movable between a closed position shown in FIG. 4 and an open position 
shown in FIG. 5 which allows the patient access to the mouthpiece (79). 
The internal components of the inhaler, namely the support block, the 
breath-actuation mechanism, the top spring and the valve assembly of the 
aerosol container have been omitted to more clearly illustrate the priming 
mechanism. A linking member (85) pivotally mounted at one end (87) to the 
cover (81) and at the opposite end (89) to a roller (91) is provided to 
translate movement of the cover (81) into movement of the body portion 
(41) of the aerosol container. The roller (91) is slidably mounted in a 
guide slot (93) formed in the inner wall of the housing (77). The housing 
is desirably provided with two such linking members (85) one arranged 
either side of the housing (77) to facilitate movement of the aerosol 
container. 
After the patient has used the inhalation device (75), the cover (81) is 
returned by the patient to protect the device against contamination by 
dirt, moisture ingress etc. Closing the cover (81) drives the roller (91) 
from the position shown in FIG. 5 to that shown in FIG. 4 with the upper 
surface (95) of the roller (91) engaging the ferrule (43) of the aerosol 
container, thereby displacing the body portion (41) of the container 
against the top spring (not shown) and relative to the valve member (not 
shown) and charging the metering chamber (also not shown) of the valve 
assembly with the next dose of medicament. 
The extent of roller (91) displacement and hence lift imparted to the 
aerosol container is proportional to the extent of closing of the cover 
(81). In use, the inhalation device (75) is held in the hand such that the 
housing (77) approximates to the vertical. 
When the next dose falls due, the patient re-opens the cover (81) causing 
the roller (91) and body portion (41) of the container to return to the 
position shown in FIG. 5. However, while movement of the former continues 
unhindered, the ferrule (43) of the aerosol container is engaged by the 
interrupter element (not shown) of the breath actuation mechanism as 
described above, thereby arresting movement of the container and 
preventing the dose of medicament held in the metering chamber from being 
dispensed until the patient inhales through the mouthpiece (79). This 
priming mechanism could also be used in non-breath-actuated inhalers to 
reset the valve. 
Each of FIGS. 6 to 12 illustrates an alternative arrangement of valve 
assembly in accordance with the invention. Each valve assembly is shown in 
the closed, non-dispensing position with the valve member displaced fully 
outwards. 
Referring to FIG. 6, the innermost end of the valve member (9) is provided 
with a cutaway (103) instead of a filling groove to allow material (from 
the aerosol container--not shown) to enter the metering chamber (7) when 
the valve member (9) is in its closed, non-dispensing position. The larger 
dimensions of the cutaway (103) allows material to enter (or leave) the 
metering chamber (7) under the action of gravity without the flow of 
material being significantly impeded. 
Referring to FIG. 7 the innermost end of the valve member (9) is provided 
with a neck portion (105) of smaller cross-section than the remainder of 
the valve member (9) which, when the valve member (9) is in the closed, 
non-dispensing position, extends through the opening (4) of the metering 
chamber (7). The relative dimensions of the neck portion (105) and the 
opening (4) are such that the space defined therebetween allows material 
to freely enter or leave the metering chamber (7) under the action of 
gravity without the flow of material being significantly impeded and any 
gas or vapour that may be in the metering chamber (7) to exit therefrom. 
Referring to FIG. 8, the innermost end of the valve member (9) is provided 
with an inlet orifice (107) which communicates via an inlet passage (109) 
with a transfer port (111). The valve member (9) is arranged such that the 
transfer port (111) is disposed inside the metering chamber (7) when the 
valve member (9) is in the closed, non-dispensing position, thereby 
allowing material to pass from the aerosol container (not shown) to the 
metering chamber (7), and outside the metering chamber when the valve 
member (9) is in the dispensing position (not shown). The valve member (9) 
is desirably provided with a side orifice (113) which allows substantially 
all the entire contents of the container to be dispensed therefrom. 
Referring to FIG. 9, the valve assembly comprises an inner housing (115) 
which together with a sealing gasket (117) surrounds and secures the valve 
assembly in position. The inner housing (115) defines a chamber (119) 
which communicates with the opening in the inner sealing gasket (15) 
leading into the metering chamber (7), having at one end thereof an inlet 
passage (121) provided with a dip tube (123). The provision of a dip tube 
(123) allows an aerosol container fitted with such an assembly to be used 
in a substantially upright position. Material may pass from the chamber 
(119) to the metering chamber (7) through the opening (4) formed between 
the neck portion (105) of the stem and the sealing gasket (15). 
Referring to FIG. 10, the valve member (9) is formed with a tubular portion 
(125) sealingly extending through an opening (4) in the inner sealing 
gasket (15). One end of the tubular portion (125) is provided with an 
opening (127) communicating with the interior of the aerosol container 
such that when the aerosol container is inverted, the tubular portion 
(125) is filled with material from the container. The tubular portion 
(125) of the valve member (9) has a close but not exact fit within the 
hollow body (5) to define a channel (129) running therebetween. 
The valve member (9) is arranged such that the transfer port (133) of the 
tubular portion (125) is disposed inside the hollow body (5) in the 
closed, non-dispensing position, allowing material to pass into the space 
vacated by the tubular portion (125) as the valve member moves to the 
dispensing position, but disposed outside of the hollow body (5) in the 
dispensing position, thereby allowing the material contained therein to 
exit to the outside environment via transfer port (25) as described above. 
FIGS. 11 and 12 illustrate valve assemblies where the valve member (9) is 
completely disengaged from the opening (4) of the metering chamber (7) 
when the valve member (9) is in the closed, non-dispensing position. In 
FIG. 11 the opening (4) is sealed by the end of stem (135) filling the 
opening and in FIG. 12 the end of the stem is provided with a deformable 
annular ring (136) which plugs the opening (4) when the valve member (9) 
is depressed to prevent additional material entering the chamber (7) from 
the aerosol container (not shown). In this manner, the opening (4) may be 
dimensioned to allow material to move freely into the metering chamber (7) 
as described previously for the valve assembly shown in FIG. 7. An annular 
ring (30) is provided on the valve member (9) to support the deformable 
annular ring (136). 
FIG. 13 illustrates an inhaler of the invention including a breath-actuated 
mechanism comprising a vane (57), catch (63), and rocker (59). 
When the patient inhales operating the breath-actuating mechanism, the 
aerosol container (172) is moved under the influence of the spring (174) 
firing the valve.