Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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APPARATUS FOR HOLDING AND DISPENSING
AN AIR MODIFYING AGENT
The present invention relates to an apparatus for holding an air modifying
agent and
dispensing the agent into surrounding air, and more particularly to such an
apparatus
capable of providing a continuous flow of air modifying agent into surrounding
air.
The expression "air modifying agent" used herein includes particularly, but
not
exclusively, chemical agents which have a beneficial use in air and which are
capable
of diffusing into air in the form of a vapour, such as for example perfumes;
fragrances,
insecticides, repellants of insects and other animal pests, and air freshening
and
deodorising substances.
A variety of designs of apparatus for dispensing an air modifying agent is
known, in
which the agent vapour flows from the apparatus in a continuous manner. Such
known
apparatus may generally comprise a support member supporting a solid carrier
which
contains the agent in a volatile form. The expression "volatile" used herein
to refer to
an air modifying agent refers to the ability of the air modifying agent to
diffuse into air
in vapour form from a surface of the solid carrier at any convenient rate of
diffusion
while the apparatus is in use.
The support member may be in the form of a container which encloses an
interior air
space above a surface of the carrier, the interior air space being in air flow
communication with the surrounding air via one or more apertures. The
apertures) may
be openable and closeable, in order to control the flow of agent from the
interior'air
space.
The solid carrier for the air modifying agent may typically comprise an
absorbent pad
or block or a gel in Which the agent is contained, optionally with a solvent
such as water
to improve the volatility of the agent. As agent is dispensed into the
surrounding air,
the volatility and accessibility of the remaining amount of agent in the
carrier is reduced,
and eventually the flow of agent in vapour form out of the apparatus will stop
or become
negligible. The~apparatus is then said to be exhausted.
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I~nov~m apparatus of this type suffer from the disadvantage that it is often
not easy to see
when the apparatus has become exhausted anal needs to be replaced, or
recharged with
fresh air modifying agent and any required liquid.
WO-A-98/18503, the disclosure ofwhichis incorporated herein by reference,
describes
and illustrates (Figure 4) an apparatus for holding and dispensing an air
modifying
agent, in which electrodes are placed in contact with the air modifying agent
and the
liquid in a geI carrier, to provide a simple electrochemical cell the voltage
of which is
applied across an electrical consumer such as a light-emitting diode (LED). On
exhaustion of the apparatus the voltage falls to zero and the LED stops
glowing.
However, such an arrangement is relatively expensive to manufacture.
It is an object of the present invention to go at least some way towards
overcoming the
above disadvantages, or at least to provide an alternative to known apparatus,
whereby
i 5 an easy visual inspection o~the apparatus will determine whether or not it
is exhausted.
According to the present invention there is provided an apparatus for holding
an air
modifying agent and dispensing the agent into surrounding air, the apparatus
comprising
a support member supporting a solid carrier which contains the agent in a
volatile form
and having an air space above the surface of the carrier, the air space being
in operative
air flow communication with the surrounding air for dispensing the agent in
vapour
form into the surrounding air, wherein said support member is configured to
adopt a first
orientation :m initial use, and to displace from said first orientation in
response to
movement of the centre of mass of the apparatus as said solid carrier
vaporises.
The expression "solid carrier" used herein includes all solid and semi-solid
substances
or structures capable of retaining within their volume a solvent such as water
and an air
modifying agent dissolved thexein. The carrier need not have complete
dimensional
stability, and indeed it is prefeiTed that shrinkage of the bulk of the solid
carrier will take
place as the air modifying agent and solvent evaporates. Such shrinkage will
enhance
the movement of the centre of mass of the solid Garner, which is a feature of
the present
invention.
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Examples of such solid carriers include gels (for example natural or synthetic
polysaccharide gels) and absorbent mats, felts, pads or wicks. Gels are
preferred, for the
reason stated above relating to shrinkage. The solid Garner may be permanently
solvated (e.g. hydrated) prior to use, or may be stored in a relatively
unsolvated (e.g.
dehydrated) form and be solvated when required for use.
The support member may suitably comprise a cantainer holding the solid carrier
in an
interior space of the container, the air space above the Garner being provided
by part of
the interior space of the container and the container being provided with one
or more
apertures for air flow communication between the air space and the surrounding
air.
The container may suitably be formed as an assembly of two parts which are
movable
relative to each other, the parts defining the one or more apertures
therebetween on
relative movement of the parts. The parts may suitably be of generally
hemispherical
shape, the two parts together forming a ball. The relative movement may, for
example,
be a partial pulling apart along a pole-to-pole axis, or may be a relative
rotation about
the said pole-to-pole axis. The parts are preferably heldtogether by
conventionalmeans
to prevent complete separation, while still permitting the required degree of
relative
movement to define the one or more apertures.
To enable the apparatus to perform a tipping action as the centre mass of the
solid
carrier moves during evaporation of the air modifying agent, an external
formation may
be provided, suitably at a base region of the support member. The formation
may
conveniently comprise a flattened portion of an external wall surface of the
support
member or a projection such as a spike~on an external wall surface of the
support
member.
This external formation defines a "footprint" area, as follows. Provided that
the overall
centre of mass of the apparatus lies directly above the "footprint" area, the
apparatus is
stable and will not tip. However, as soon as the overall centre of mass of the
apparatus
moves to lie outside the area directly above the "footprint" area, the
apparatus will tip
over.
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To achieve this effect, the apparatus may conveniently be arranged so that a
significant
poution of the apparatus (e.g. the upper part of the ball in the arrangement
described
above) is above the centre of mass of the solid carrier, whereby the centre of
mass of the
support member can be above the centre of mass of the solid carrier as the
point of
S exhaustion is approached. By providing the external foot formation so that
the
apparatus is supported during use with the imaginary line connecting the two
centres of
mass set at an angle to the vertical (e.g. up to about 20°, more
preferably between about
and about 15°), the downward movement of the centre of mass of the
solid carrier as
the air modifying agent is exhausted can be made to result in the overall
centre of mass
of the apparatus moving outside the area directly above the "footprint" of the
foot
formation, causing the apparatus to tip over.
The change in orientation of the apparatus enables a simple visual inspection
of whether
or not the apparatus is exhausted of air modifying agent.
The an angement of the solid carrier with respect to the support member of the
apparatus
must be carefully chosen to produce the desired lateral movement of the centre
of mass
over the tipping fulcrum at the edge of the "footprint" during evaporation of
the air
modifying agent. However, these criteria are not difficult to observe in
practice, and are
well within the abilities of one skilled in this art.
For further understanding of the present invention, an embodiment will now be
described, purely by way of example and without limitation, with reference to
the
accompanying drawings, wherein:
2S
Figure 1 shows a vertical cross-section view through an air freshener prior to
use;
Figure 2 shows a corresponding view of the air freshener of Figure 1 ready for
use;
Figure 3 shows a corresponding view of the air freshener of Figure 2 after the
air
freshening agent is exhausted;
Figure 4 shows an underside view of the air freshener of Figures 1 to 3;
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Figure 5 shows a vertical cross-section view through a preferred air freshener
priox to
use;
Figure 6 shows a corresponding view of the air freshener of Figure 5 ready for
use; and
Figure 7 shows a corresponding view of the air freshener of Figure 6 after the
air
freshening agent is exhausted.
Referring to Figures 1-4 of the drawings, there is shown an air freshening
apparatus
which comprises a support member for the air freshening agent, in the form of
a
container formed in two partially separable hemispherical halves l, 2, the
halves being
held together via an internal telescopic sliding arrangement 3 aligned on a
pole-to-pole
axis A and provided with cooperating proj ections 4 and recesses 5 to enable
the desired
degree of manual separation of the halves to be selected within a range. The
partial
separation of the halves provides an equatorial aperture 6, through which an
interior air
space 7 of the container above a solid earner 8 containing the air freshening
agent is in
air flow communication with the surrounding air.
The solid carrier 8 is of conventional construction, and most preferably
comprises a gel
containing water and the air freshening agent.
The exterior surface of the lower 2 of the two container halves is provided at
its base
with a pair of flat feet 9, 10 formed simply by flat regions of the container
surface. One
foot 9 is a central foot, concentric with the pole-to-pole axis A of the
container. The
other foot 10 is offset from this central axis. Foot 9 can be used to stand
the apparatus
if a tipping effect is not desired. Foot 10 can be used if a tipping effect is
desired, as
described below.
In its condition immediately prior to use (Figure 2), the gel carrier 8
(containing water
3 0 and the air freshening agent) practically fills the lower 2 of the two
container halves, and
the upper surface 11 of the gel earner would be horizontal if the container
would be
resting on the central foot 9. However, in fact the container is resting on
the other foot
10, so that the upper surface 12 of the gel carrier lies at an angle: In this
condition, the
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centre of mass of the solid carrier is sufficiently high up the pole-to-pole
axis A that the
centre of mass of the total apparatus lies to the left of the fulcrum 12 as
viewed in
Figures 1 acid 2. The container therefore rests stably on the foot 10.
As the air freshening agent of the gel carrier 8 becomes exhausted, and the
gel carrier
8 gradually dehydrates, the bulk of the gel carrier 8 shrinks within the
container towards
the base region. The centre of mass of the solid carrier moves down the pole-
to-pole
axis A, but the mass of the solid carrier substantially reduces, so that the
over all centre
of mass of the total apparatus thereby moves up and to the right as viewed in
Figures 1
and 2, by virtue of the angle at which the pole-to-pole axis A is oriented. As
soon as the
centre of mass of the total apparatus moves to the right of the fulcrum 12,
the apparatus
tips onto the upper half 1, i.e. into the orientation indicative of the
"exhausted" condition
of the gel carrier 8, as shown in Figure 3.
The parts of the container are suitably of moulded plastics and are made in
generally
conventional manner. To manufacture the apparatus, the gel carrier 8,
containing also
the air freshening agent, is poured in liquid form into the lower 2 of the two
container
halves, and allowed to set while the half is held horizontal. The upper half 1
is then
secured in place.
The invention provides a silnple and effective way of visually determining
when an
apparatus of this general type has become exhausted of its air modifying
agent.
Figures 5 and 6 are views corresponding to Figures 1 and 2 of a preferred form
of air
freshening apparatus which is a modified form of the apparatus described
above, items
which are the same as in Figures 1 and 2 having been given the same reference
numerals
as in those figures. The air freshening apparatus of Figures 5 and 6 differs
from that of
Figures 1 and 2 in that: the'lower 2 of the container halves is not formed
with feet 9 and
10, instead it is formed (during an injection moulding process) with a small
spike 13 so
that the apparatus can stand as shown with the surface 11 at an angle to the
horizontal;
the lower one of the two members forming the telescopic arrangement 3 is open
at the
top (this being more straightforward for injection moulding); and at the top
of the upper
one of the two members forming the telescopic arrangement 3, there is press-
fitted
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inside it a ball-bearing 14 (for example about 7.5 grams in weight) to assist
the
apparatus to tip over as in the apparatus described above after the air
freshening agent
in gel carrier~8 (the gel carrier 8 being, for example, initially about 60
grams in weight)
has been exhausted - see Figure 7.
The invention has been described above in general terms, and the illustrated
embodiments are included purely by way of example, and without limitation.
Variations
and modifications as will be readily apparent to one of ordinary skill in this
art are
intended to be included within the scope of this application and any
subsequent
patent(s).
