Note: Descriptions are shown in the official language in which they were submitted.
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WO 97136801 PCT/BE97/00039
METHOD AND APPARATUS FOR MA~NTAINJNG AND GENERATING A PRESSURE WITHIN A
PRODUCT DISPENSER
This invention refers to a method and a device for
generating pressure in a spray can and the like, as well
as to a spray can equipped with such device.
More particularly, it refers to a method for generating
pressure of the type whereby at least two products are
brought into contact with each other in such a way that,
by doing so, a gas is produced and, thereby, a gas
pressure is created.
According to a known technique which is described in the
European Patent No. 0 033 377, the aforementioned
products are stocked in different compartments of a
pouch. After installing this pouch in a spray can, the
products, by subsequently breaking the partition walls
between the aforementioned compartments, are brought into
contact with each other, as a result of which a gas is
created in the pouch, expanding this pouch. The expansion
of the pouch is used to dispense the product present in
the spray can, as well as for systematically breaking the
partition walls of the subsequent compartments.
This technique shows as a less favourable characteristic
that the pressure in the spray can is not constant, but
fluctuates. Each time two compartments are connected to
each other, a gas production occurs which causes a press-
ure increase. The two subsequent compartments are only
connected to each other as soon as the pouch has realized
a definite expansion, whereby the pressure, however, is
reduced. Taking into account that the number of compart-
ments is limited due to constructive causes, the afore-
mentioned pressure fluctuations are relatively large.
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This known technique also shows the disadvantage that the
pouch with the compartments has to be assembled quite
accurately in order to let the partitions between the
compartments break at the right moments.
The invention aims at a method and device with which one
or more of the aforementioned disadvantages can be
excluded.
To this aim, the invention, first of all, concerns a
method for generating pressure in a spray can, whereby at
least two products are brought into contact with each
other in such a way that, ~y doing so, a gas is produced
and, thereby, a gas pressure is created, with the
characteristic that the products are brought together via
a passage, whereby the flow rate via this passage is
commanded by means of a movable element which, in its
turn, is controlled by the gas pressure prevailing around
the device.
According to a preferred form of embodiment, the flow
rate of the passage is regulated by means of a pressure-
reactive regulator, more particularly a pressure-reactive
valve reacting progressively onto the pressure in the
spray can, such that the passage is closed every time the
pressure in the spray can has obtained a well-defined
value, but is reopened as soon as the pressure decreases
below the aforementioned value.
Hereby is obtained that the two products are brought
together progressively, whereby the gas production occurs
precisely in function of the quantity of gas necessary to
restore the normal dispensing pressure after each
activation of the spray can.
According to a variant which offers the advantage that it
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can be realized with a considerably cheaper installation,
- the passage is closed initially and, by means of the
moving element, a remaining passage is created once, as a
result of which the products concerned react completely.
The invention also refers to a device for the realization
of the aforementioned method. To this aim, it consists of
a receptacle wherein a first of aforementioned two
products is a~ailable; a closable or closed passage via
which, by means of opening or realizing an open passage,
the first product and the second product can be brought
into contact with each other; and a movable element which
can be controlled by means of the pressure surround~ng
the device and which performs the opening, and eventually
closing, of the passage, respectively the production of
such a passage.
The first product preferably is a liquid, so that, for
the movable element, use can be made of a valve. This
valve provides in that the liquid can leave the
receptacle and come into contact with the second product.
The expulsion of the liquid from the aforementioned
receptacle, at least in the open position of the valve,
can be performed in different manners. According to an
advantageous possibility of the invention, the device
comprises means which allow for placing the liquid under
pressure in the receptacle, assisted by the pressure
which is created in the spray can, such that no separate
pressure means for the expulsion of the liquid are
necessary. In a preferred form of embodiment, these means
are formed by a wall of the aforementioned receptacle
which, to this aim, is manufactured from a slowly gas-
permeable material.
The products which are brought into contact with each
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other via the passage can be the products which react
with each other for the production of a gas, but may also
be products which do not react with each other, but
provoke a reaction.
According to a first interesting possibility, the first
product consists of a liquid acid, whereas the second
product consists of salt in solid condition.
According to a second interesting possibility which
offers the advantage that no liquid acid has to be
handled, the first product consists of a dissolvent, for
example water, and the second product consists of a dry
composition of an acid and a salt, such, that a reaction
~5 with formation of a gas will be performed only when the
acid and/or salt comes into dissolved condition by adding
the first product to the second product.
~n a preferred form of embodiment, the device is equipped
with a pressure-reactive flow regulator which is manufac-
tured in such a way that the passage is closed as soon as
the pressure reaches a value which is higher than or
equal to the dispensing pressure of the spray can for
which the device is intended, and is closed at ~east also
at a pressure which is smaller than or equal to atmos-
pheric pressure. As a result of this, the device can
simply be stored in an atmospheric environment before
being installed in a spray can, without the gas
generation starting. Furthermore, the device can simply
be activated by initially creating a pressure in the
container of the spray can in an external manner.
The invention also refers to a device for generating
pressure in a spray can, whereby at lea5t two products
are brought into contact with each other such, that, by
doing so, a gas is produced and, thereby, a gas pressure
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is created, characterized in that the first product
consists of a dissolvent and the second product consists
of a dry composition of salt and an acid, prefera~ly in
the shape of a block of compressed powder, regardless of
the manner in which these products are brought together.
In order to better show the characteristics of the
invention, by means of example without any limitative
character, several preferred forms of embodiment are
descri~ed in the following, with reference to the
accompanying drawings, wherein:
figure l schematical~y shows a spray can equipped
with a device according to the invention;
figure 2 shows a practical form of em~odiment;
figure 3, on a larger scale and in cross-section,
shows the part which is indicated by arrow F3 in
figure 2;
figure 4 shows a cross-section according to line IV-
IV in figure 3;
figures S, 6 and 7, on a larger scale, show the part
which is indicated by F5 in figure 3, for different
positions;
figure 8 shows an alternative of the part which is
indicated by F8 in figure 3;
figure 9, in cross-section, shows a variant of a
device according to the invention;
figures lO and ll, on a larger scale and for
different positions, show the part which is indicated
by FlO in figure 9;
figures 12 and 13 show the bottom part of another two
variants;
figures 14 to 16 show the device from figure 13 in
different positions;
figures 17 and 18 show another device according to
the invention, for two different positions;
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figures 19 to 21 show a further form of embodiment,
also for different positions.
As shown in figure 1, the invention refers to a device 1
which can be installed in a spray can 2, allowing to
create an excess pressure P in the container 3 of the
spray can 2, such that the product 4 to be dispensed,
present in the spray can, is expelled from the container
3, for example, by means of a dip tube 5, as soon as the
usual valve 6 or similar is activated, more particularly,
is opened by means of pressing a push-button 7.
According to the form of embodiment shown schematically
in figure 1, use is made of two products 8 and 9 reacting
to a gas 10 when brought together. Prefera~ly products
are used reacting mutually to the formation of car~on
dioxide gas. The first product 8 to this end preferably
consists of an acid in liquid condition, or of an acid
dissolved in a liquid, for example, citric acid. The
second product 9 preferably consists of a salt, for
example, calcium carbonate, barium carbonate, or sodium
bicarbonate.
As represented, the device 1 for the generation of the
gas 10 substantially consists of a receptacle 11 wherein
the first product 8 is situated; a r~Cc~e 12 via which
the first product 8 can come into contact with the second
product 9; and a pressure-reactive ~low regulator 13,
with a mo~able element, such as a close-off valve, with
which the passage 12, in function of the surrounding
pressure around the device 1, thus, of the pressure in
the container 3, is closed-off or not.
The pressure-reactive flow regulator 13, in this case, is
of such nature that the passage 12 is closed-off as soon
as the value of the pressure in the container 3 is higher
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than or equal to a pre-defined value, and is reopened as
soon as a pressure decrease occurs in the container 3.
Hereby, the aforementioned pre-defined value is equal to
the necessary dispensing pressure.
Actually, the aforementioned products 8 and 9 must not
each be placed within a receptacle. It is, however,
sufficient that they are separated from each other and
they can be ~rought together in a controlled manner by
means of the pressure-reactive flow regulator.
Principally, one of the two products, in this case,
product 9, may be present freely in the container 3 of
the spray can.
The functioning and use of the device l are substantially
as follows.
In non-operative condition, the container 3 is filled
with a defined quantity of product 4 to be dispensed and
a quantity of gas lO with which the container 3 is held
under a pressure P. When pressing the push-button 7, the
valve 6 is opened and the product 4, via dip tube 5 and a
dispensing opening 14, is expelled outwards and eventual-
ly atomized. As a result of this, the pressure in the
container 3 decreases. The pressure decrease is percepted
by the pressure-reactive flow regulator 13 which hereby
opens the passage 12. As a result of this, the product 8
from the receptacle 12 comes into contact with product 9,
which causes the generation of gas lO and the restoration
of pressure P.
As soon as the pressure P has reached its normal value,
the flow regulator 13 closes the passage 12 again. The
supply of product 8 to product 9 is thus interrupted, as
a result of which the gas production is stopped and the
pressure in container 3 does not increase any more.
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In order to expel the product 8 from the receptacle ll,
according to the invention different techniques may be
employed.
According to one possibility, the receptacle 11 is set
under pressure by providing therein, along with the
product 8, also a quantity of gas under pressure, with a
pressure that is preferably higher than the dispensing
pressure of the spray can.
In the figures 2 to 7, a practical form of embodiment of
the device 1 is shown.
Here, the second product 9 is placed in a chamber 15
which connects to the aforementioned passage 12, which
offers the advantage that the product 8, flowing out of
the passage, directly comes into contact with product 9,
which guarantees an immediate reaction. The generated gas
10 can leave the chamber 15 via outlet openings 16.
The pressure-reactive flow regulator 13 consists of a
pressure-reactive element 17 and a movable element
cooperating with it, more particularly a va}ve 18, which
is mounted in the passage 12.
The pressure-reactive element 17 can principally consist
of any elastically compressible construction. In the
given example, it consists of a housing }9, one wall of
which is formed by a diaphragm 2~, which can be moved
under the influence of the pressure present in the spray
can and consists, for example, of a thin corrugated steel
plate. The reaction force during indentation of the
diaphragma 20 is substantially deliVered by means of an
elastic element 21 which is enclosed in the housing 19.
It is clear that the housing 19 is gas-ti~ht. The gas
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present in the housing l9, for example, air under
atmospheric pressure, and the elasticity of the diaphragm
20 of course also provide a force component exerting an
influence upon the displacement of the diaphragm 20.
In a form of embodiment which is particularly simple to
realize, the elastic element 21 is to be formed by a
piece of rubber or plastic tube which, in compressed
condition, is to be enclosed into the housing l9 either
straight or in wound-up condition.
The valve 18 preferably consists of a needle-shaped valve
body 22 wherein a recess 23 is provided, and a valve seat
24 in which the valve body 22 can shift axially such,
that the passage 12 is open when the recess 23 is located
in front of valve seat 24.
Herein, the valve seat 24 can consist of an O-ring
mounted in the passage 12.
The valve body 22 at one end cooperates with the
diaphragm 20 and can be fixed to it or not.
In the form of embodiment of figure 3, the receptacle ll
has a wall 25 which is manufactured from a material
allowing a slow permeation of gas under application of a
pressure difference. This wall 25 must not be permeable
for all gases, it is sufficient that it is permeable f~r
the produced gas lO, first of all for carbon dioxide.
More particularly, this wall 2~ shall consist of semi-
rigid material, for example polyurethane.
In order to obtain a sufficient permeability, the wall 25
shall be manufactured relatively thin, for example, by
means of a thermo-forming process. In order to give it
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nevertheless sufficient stability it may be provided with
steps.
The configuration of the receptacle 11, the chamber 15
and the housing 19 is preferably as shown in figure 3,
which means that the chamber 15 is situated between the
receptacle ll and- the housing 19, that the valve 18 is
arranged in the wall 26 between the receptacle 11 and the
chamber 15 and that the diaphragm 20 is situated Opposite
to the wall 26 wherein the val~e 18 is arranged. The
product 9 is preferably formed by a ring-shaped block of
compressed salt, which is positioned around the ~alve
body 22.
The functioning of device 1 is as described hereafter.
When the device 1 is in an atmospheric surrounding, the
valve body 22 assumes a position as shown in figure 5,
because the diaphragm 20 bulges upward. By this, the
passage 12 is closed and the first product 8 cannot leave
the receptacle 11.
After the device 1 being installed in a spray can 2,
first of all, via an external supply, in the spray can 2
a pressure can be applied which, for example, is somewhat
higher than the normal dispensing pressure. This pressure
effects onto the diaphragm 20, by which the valve body 22
shifts up to the position shown in figure 6.
Taking into account that the wall 25 is gas-permeable, a
pressure is also built up in the space 27 of the
receptacle 11. After a while, the pressures in the
container 3 and in the space 27 equal each other.
3~ When product 4 subsequently is dispensed, the pressure in
the container 3 decreases. This pressure decrease,
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however, is not immediately followed by a similar
pressure decrease in the space 27. When the pressure in
the container 3 is reduced under the normal dispensing
pressure, the valve body 22 obtains a position as shown
in figure 7. Taking into account that the pressure in the
space 27 at that moment is higher than in the container
3, the product 8 is expelled from the receptacle ll via
the opened valve 18.
As a result of the reaction of the released product 8
with product 9, gas is produced which, via the outlet
openings 16, comes into the container 3. ~ereby, the
pressure increases again, causing the diaphragm 20 to be
indented again. When the desired dispensing pressure is
obtained, the diaphraqm 20 is indented such, that the
condition of figure 6 is reached again, whereby the
passage 12 is closed and the gas generation stops.
It is clear that in this manner a constant pressure is
maintained automatically in the container 3.
Instead of a permeable wall 25, pressure passage means of
another type can be applied. According to an alternative,
the wall 25 is not permeable for gas and, as schematic-
ally shown in figure 3, a return valve 28 is appliedallowing that the gas lO from the container 3 can flow
into the receptacle ll when the pressure in the container
3 is higher than the pressure in the receptacle ll.
Of course, still other forms of embodiment are possible.
In figure 8, for example, a variant is shown whereby the
elastic element 21 consists of a ring-shaped block from
elastically compressible material, for example, foam
plastic or rubber.
According to a not represented variant, no elastic
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element 21 will be used, and the reactive force is only
de~ivered ~y the the own elasticity of the diaphrag3 20
and the gas pressure exerted thereon.
Figure 8 also shows that the valve body 22 may be fixed
to the diaphragm 20, in this case by clamping in a seat
29 in the center of the diaphragm.
As also shown in figure 8, each of the outlet openings 16
can be provided with a return valve 30. This may consist
of an elastic band which is stretched over the outlet
openings with very little tensioning force, such as, for
example, the shown O-ring 31.
lS Because of the presence of the return valve 30, the
generated gas 10 can escape, the products 4 and 9,
however, can not come into direct contact with each other
which can be desirable in certain applications. In this
manner, the product 9 also cannot spread itself in the
container 3, for example, by solution in product 4.
Hereby, the not yet reacted product 9 remains in the
proximity of the passage 12 so that the release of a
quantity of product 8 always results in an immediate
generation of gas.
Such a return valve can also consist of a very small
opening or a porous part in the wall of chamber 15,
whereby this opening of this porous part allow that gas
10 can leave the chamber 15, but no liquid can penetrate
in the opposite direction.
In figure 9, a form of embodiment is represented whereby
the second product 9 consists of a composition of
components which, in undisso~ved condition, do not react
with each other, in dissolved condition, however, will
react with each othe_, whereas the first product 8 is
.
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formed by a dissolvent, for example water, with which one
or both of the aforementioned components can be
dissolved.
The device 1 shows a similar construction as the
embodiment from figure 8. Conforming parts, then, are
indicated with the same references.
Instead of the receptacle 11 being filled with a liquid
acid, it is now filled with a dissolvent, preferably
water.
The product 9 preferably consists of a mixture of dry
components which will react with each other when being
dissolved in a li~uid, more particularly in the product
8. More particularly is preferred that these components
are compressed to a single block or similar. Hereby, the
components can consist o~ a salt, on one hand, and an
acid in dry condition, for example in the shape of srains
and/or powder, on the other hand.
The device 1 from figure 8 is, analogous to the
embodiments from figures 3 to 8, provided with a valve 18
which is controlled by means of a pressure-reactive
element 17.
The pressure-reactive element 17, in this case, is formed
by a compressible housing 19 which is not connected to
the chamber 15 and consists of two metal diaphragmas 32-
33 which enclose a space 34 and are welded together bytheir edges.
In figure 9, exclusively as an example, a valve 18 is
shown the design of which differs from the one shown in
figure 3. The valve 18 shows a needle-shaped valve body
22 which fits through the passage 12 and which is
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provided with two closing members 35-36 which can
cooperate with two valve seats 37-38, such, that a
closure is obtained when the valve body is pushed either
into the one extreme position or into the other extreme
position, and such, that a passage is obtained when the
valve body takes a position situated between these two
extreme positions.
In the represented example, the closing members 35-36
consist of enlargements in the valve body 22, whereas
the valve seats 37-38 are formed by the edges, situated
at opposite sides of the wall 26, of the passage 12
provided in this wall 26. Between the closing members 35-
36, recesses 39 can be provided in the valve body 22 in
order to render the passage of liquid in the open
position of the valve more easily.
In the embodiment of figure 9, the valve body 22 is
loaded by means of an elastic element, such as a bow 40,
which provides for that the valve body 22 does not get
off the pressure-reactive element 17.
To a great extent, the working is analogous to the one of
the aforementioned forms of embodiment and will be
described step-wise in the following, in reference to
figures 9 to ll.
In figure 9, the device l is subject to atmosperic
conditions. The pressure delivered by element 17, hereby,
3C is such that the valve body 22 is pushed upward and a
sealing of the passage 12 is obtained because the closing
member 36 becomes situated against the valve seat 38.
When the device is situated in a spray can 2 and the
latter is initially activated by realization, via the
external way, of a gas pressure, the pressure-reactive
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element 17 is pushed inwardly, the valve body 22 is
shifted, and the passage 12 is closed off, in this case,
because the closing member 36 becomes situated upon valve
seat 37, as shown in figure 10.
When the pressure in the container 3 of the spray can 2
diminishes, because product 4 is dispensed, the pressure
in the chamber 15 will also diminish, as a result of
which the pressure-reactive element 17 enlarges and the
valve body 22 comes into a position as shown in figure
11, as a result of which the product 8, in this case
water, flows via passage 12 into the chamber 15, under
influence of the pressure which prevails in the space 27
and which develops in the same manner as described in
reference to figure 3.
Because the water comes into contact with the mixture of
acid and salt, one or both of these components will
dissolve and they will react with each other, as a result
of which gas develops and a pressure increase is created
in the chamber 15 and, thereby, also in the container 3.
With the increase of this pressure, the pressure-reactive
element 17 is compressed again, and, when a defined
pressure is reached, the valve body 22 comes bac~ into
the position of figure 10, whereby the supply of water is
interrupted and, as a result of this, also the
aforementioned reaction is terminated.
In-consideration of the fact that with certain reactionS
of this kind, sometimes water is produced, it may be
necessary to add still further substances to the product
9 in order to prevent the development of a chain
reaction. This can easily be determined from the
respective reaction comparisons as well as in an empiric
manner.
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16
When the device l from figure 9 is meant to be applied in
a product 4 which also forms a dissolvent for the
components of which the product 9 consists, the openings
l6 will have to ~e provided with a return valve 30, such
s as, for example, an elastic band 41. In this case,
however, measures will have to be met in order to achieve
that the chamber 15 can be pressurized by the initial
pressurization of the container 3.
In figure 12, a variant is shown whereby the passage 12
partially is formed by a hollow 42 in the valve body 22.
This hollow 42 gives out into the receptacle ll. In the
wall surrounding the hollow, a radial opening 44 is
provided which, by the movement of the valve body 22, is
either situated opposite to a wall part 45 or opposite to
a wall part 46 or opposite to an opening 47 giving out
into chamber 15, whereby a sealing is obtained in the
first two cases. The functioning of the e~ho~; ~ont from
figure 12 can be compared to the one from figure 9.
In figures 13 to 16, a form of embodiment is represented
with which a single generation of gas is provided. This
device whi¢h can be called a "One Shot" gas generator,
provides for that after half of the lifetime of a spray
can, the pressure in this spray can is increased again.
The pressure in the spray can, thus, is not constant, but
due to the fact that a pressure-reactive movable element,
such as a valve, is used, the advantage is obtained that
the moment in which the gas will be generated
additionally, can be defined very precisely in function
of the pressure in the spray can, which is not the case
with the known devices using a pouch with compartments
whereby the partition walls are broken down by
destructing them.
As shown in the figures 13 to 16, the device l uses a
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motion system 48 which is basically formed by a wall part
49 in the shape of a diaphragm which delimits the chamber
15 and, by means of a well-defined pressure difference,
can switch from position A to B and vice versa.
The motion system 48 cooperates with a movable element
with which the passage 12 can be closed off, respectively
opened, which, in this case, consists of a closing
element, such as a valve 50. This valve 50 shows a
closing portion 51 which can be drawn downward out of the
passage 12, but which, however, by means of an abatment
portion 52, is prevented from slipping out of the passage
12.
Furthermore, in the form of embodiment of figures 13 to
16, coupling means 53 are provided which allow for
coupling the wall portion 49 to the valve 50. These
coupling means 53 consist in the represented example of a
snap-on coupling with hook-shaped coupling parts 54 which
can engage behind a coupling part 55.
The functioninq of the device 1 from figures 13 to 16 is
as follows.
In an atmospheric environment, a condition is obtained as
shown in figure 13.
When the spray can 2 is activated by putting it under
pressure via external ways, the wall portion 49 is pushed
inward, as a result of which coupling parts 54 are pushed
over the coupling part 55 and a condition results as
shown in figure 14.
As a result of the permeation of gas into receptacle 11,
and eventually into chamber 15, a minor shifting of the
valve body 22 may occur, for example, up to the position
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18
which is represented in figure 15.
When, during usage of the spray can 2, the pressure in
the container 3 is diminished to a well-defined value
which, in a practical embodiment, is chosen such that it
equals approximately 3 bar, the closing portion 51
obtains a position whereby li~uid from receptacle 11
comes into chamber 15 and gas is produced, as a result of
which the wall portion 4~ bulges outwardly again and the
products 8 and 9 come together freely again. As a result
of this, a large ~uantity of gas is produced which, then,
is sufficient to diffuse the total quantity of product 4.
Hereby, valve 50 takes a position as represented in
figure 16.
In figures 17 and 18, a variant is shown whereby the
passage 12 is provided with a closure 57 which can be
pushed away by means of a movable element 56. This
closure 57 consists of a closing plate 58 which is
clamped in a seat 59.
The movable element 56 consists of a valve stem with an
extremity 60 with which the passage 12 can be closed off.
The lower extremity 61 of the valve stem cooperates with
a pop-over system 62 with a bent wall portion 63 which
can, surpassing a dead point, be popped over towards the
inside, respectively outside.
The valve stem is positioned centrally by means of a
recess 64 in the extremity 61 which cooperates with a
deformation 65 in the wall portion 63, as well as by
means of an elastically bendable flange 66 which is
present around the valve stem and reaches up to the
circumference of chamber 15. This elastic flange 66
simultaneously exerts a reversing force upon the valve
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19
stem when this latter is pushed into the direction of
passage 12.
In an atmospheric environment, the device is in a
S condition as represented in figure 17.
When the device 1 is situated in a spray can 2 and, via
external way, a pressure is built up in this spray can,
the wall portion 63 pops over into a position as
represented in figure 18. As a result of this, the valve
stem, against the force of the flange 66, is pushed
upward and the closing plate 58 is pushed out of seat 59.
The closure of the passage 12, however, remains
guaranteed because extremity 60 now closes off the
passage 12.
When, as a result of dispensation of product 4, the
excess pressure in the container 3 becomes lower than a
well-defined value, for example, 3 bar, the wall portion
63 pops back into the position of figure 17 and, under
the influence of the force exerted by flange 66, the
valve stem will also return into the position of figure
17.
As a result of this, dissolvent, for example water, flows
from the receptacle 11 through the passage 12 and through
openings 67 which are provided in the flange 66. Thereby,
this dissolvent comes into contact with the components of
product 9, as a result of which these, as aforementioned,
wil~ react to a gas. They react until all of product 8 or
9 is used up. As a result of this, a pressure increase is
created in chamber 15 and container 3, as a result of
which a second load of pressure gas becomes available.
In figures l9 to 21, another variant is represented,
whereby use is made of a movable element, more
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particularly a valve 68 with a hollow valve stem 69 with,
on one hand, an inlet 70 which can cooperate with the
wall 26, and an outlet 71 which ends up into chamber 15
and which can be closed off by means of a movable wall
portion 63 which is executed analogous to wall portion 63
in the embodiment from figures 17 and 18.
In an atmospheric environment, this device 1 is in a
condition as represented in figure 19.
When the spray can 2 is put under pressure, the wall
portion 63 takes a position as represented in figure 20,
as a result of which the valve stem 69 with the inlet 70
is pushed into receptacle 11. A passage of liquid,
however, is not yet possible because outlet 71 still is
sealed.
As soon as the pressure in the container 3 becomes lower
than a well-defined value, the wall portion 63 pops back
into the position of figure 19, as a result of which the
liquid of receptacle 11 can flow, via the valve stem 69,
into chamber 15, with the result that gas is created.
Instead of, as shown in the forms of embodiment of
figures 13 to 21, making use of a movable element
consisting of a pressure-reactive valve which provides
for that the passage 12 is opened at a well-defined
pressure decrease and subsequently remains open,
according to a variant of the invention, it miqht also be
possible to use a movable element which, by its movement,
forms a passage not present up to then. Hereby,
particularly a needle or similar is intended which makes
a perforation between receptacle 11 and chamber 15.
In the devices represented in figures 9 to 21, for the
first product 8, instead of a dissolvent, also a liquid
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acid can be used, whereas for the second product 9, then,
instead of a dry mixture of an acid and a salt, use can
be made exclusively of a salt.
According to a not represented variant, the complete
device l can be put into a gas-tight extendable pouch
before installation in container 3. In this manner, any
contact between, on one hand, the product 4 and, on the
other hand, the products 8 and 9 and the gas lO can be
excluded.
The compact design of the device l, with only one
quantity of product 8 and one quantity of product 9,
offers the advantage that with a relatively small device
l, however, a large quantity of gas can be produced,
compared to the known embodiments whereby the products
are arranged in several compartments. By the fact that
large ~uantities of gas can be generated in a simple
manner, the invention is especially suited for
applications whereby the gas lO is not only used to exert
a pressure upon the product 4, but also has to mix with
the product 4 to be dispensed, for example for causing a
foam formation in the case of a product to be foamed. In
this case, the device l will contain such a ~uantity of
products 8-9 to be reacted that the generated gas lO can
as well provide for the dispensation of the product 4 as
for provision of the foaming effect.
The aforementioned device l can as well be arranged
loosely in container 3 as mounted fixedly herein.
According to the invention, the device l is not only
intended for the application in classic spray cans but
can be applied in all kinds of dispensing containers
whereby the product to be dosed is expelled under
3s pressure.
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The present invention is in no way limited to the forms
of embodiment described by way of example and represented
in the figures, but the aforementioned method and device
can be realized according to different variants without
leaving the scope of the invention.
