Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention rela-tes -to a punlp for dispensing liquicls,
gels or foalns, hereina~ter referred -to as "liquids".
In a conven-tional pressurised pack dispensing device,
such as an aerosol can, a liquid produc-t to be dispensed
S is normally stored under posit:ive pressure in admixture with
a lique-fied gaseous propellant~ l~en the product is dispensed
from this type of device, it is therefore usually accompanied
by propellan-t in liquid or gaseous form ~hich can assis-t in
atomising the product, bu$ which can in other respects be
detrimental to the product and be~dislih-ed by the consumer.
The use of a liquefied gas propellant in particular can
furthermore create a problem for the -formulator, for example
because of phase separation in the pac~ or other incompatability
with the other ingredients of the product. ~he use of a
liquefied gas propellant does, ~urthermore, add to the cost
of the product. Accordingly, it is apparent that it could
be beneficial both to the manufacturer and to the consumer
if liquid products of the type normally dispensed in aerosol
form from pressurised packs could be dispensed ~Yithout the
need to employ any liquefied gaseous propellants.
Many attempts have in the past been made to develop an
efficient and e-ffective finger-operable pump for dispensing
propellant-free liquid products in aerosol -form, as an
alternative to the conventional propellant based pressurised
pack dispensing devices. None o~ -these finger-operable pumps
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has, llowever, so far been capable OI deliver:in~ the p:rocluct
in ~ predict~bl~ and unifor~ spray pattern at near constan-t
pressure each -time the pump is actuated, irrespective of
variations in applied finger-pressure.
The main problem which has been encountered wi-th
finger-operable pumps is that delivery can commence soon
after finger force has been applied to the actuacting button,
and the pressure a-t which the product is dispensed, as judged
by the degree of atomisation, is often dependant on the finger
force applied. The nett result is that in use, pumps such
as these frequently sho~ a tendancy to dribble or drip,
particularly at the commencement and end of the dispensing
stroke, unless the user is able to depress the actuating but-ton
sharply enough to effect efficient atomisation while directing
the spray in the desired direction.
With a view to solving these problems, we have developed
a finger operable pump for dispensing liquids ~Yhich does no-t
suffer from these disadvantages.
It is -therefore an object of the invention to provide
~0 a finger-operable pump having a feed chamber of variable
volume ~hich is capable of delivering a liquid product in
atomised form, in which the spray pattern is predictably
uniform.
It is also an object of the invention to provide a
finger-operable pump which is capable of repea-tedly delivering
equal volumes of a liquid product.
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It is a -t`urt]:ler object of -the invention to provide a
finger-operable pu~p in ~hich the pressure at whi.ch liquid
product is dispensed i.s always subs-tantially the same,
irrespective of -the finger force applied to the actuator
button and the ra-te a-t which that bu-tton is depressed.
I-t is yet a fur-ther object of the invention -to provide
a finger-operable pump in ~hich when -~inger force is applied
to the actuator button, delivery of the liquid product i8
delayed ~ultil a predetermined hydraulic pressure has been
built-up within the pump, or until the actuator button and
hence the end wall of the feed chamber has been displaced
by a predetermined distance, thereby to reduce the volume of
a feed chamber within -the pump to its minimum value.
It is yet a further object of the invention to provide
a finger-operable pump in ~hich means is provided for
-triggering the delivery of liquid product in atomised form
without interruption of the adjacent surfaces of the feed
chamber within the pump which define the outline of that
chamber.
According to the invention, there is provided a
finger-operable pump for dispensing liquids comprising an
axially arranged feed chamber having a finger displaceable
end wall, axial movement of which will vary the volume of
said feed chamber; a pressure actuable valve to permit entry
of a liquid product from an external supply to the feed
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chamber, said valve ancl said feed cham~er being 90 posi-tioned
tllat clown~ard a~ial move~ellt of the finger displaceable end
~all toward s~:id valve reduces -the volllule of the fee~ chamber
ancl increases hydraulic pressure therewitllin, and upward
axial move~ent of the finger displaceable end wall away from
said valve increases -the volume of the feed chamber and
reduces hydraulic pressure therewithin; an axial c3ischarge
chamber in communication with said feed chamber; a resi.lient
means positioned co-operably with the discharge chamber for
1~ storing energy generated by the i.ncreased hydraulic pressure
~hich results -from downward movement of the finger
displaceable end wall with respect to thc feed chamber; a
discharge conduit communicating the di.scharge chamber with the
atmosphere exterior to the pump; means for releasing the
energy stored in the resilient means and for conducting the
liquid produc~t from the discharge chamber to the discharge
conduit, said means being operable to release the energy and
provide a conduit for the liquid produc-t only af-ter the finger
displaceable end wall has moved downwardly with respect to
the feed chamber by a predetermined distance, the finger
displaceable end wall forming a liquid tight seal with a
side wall of the chamber a-t least un-til after said valve
means is operated.
The pump essentially consis-ts O:e an axially arranged
feed chamber having a finger displaceable end wall. Axial
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displacemell-t of this end wall ~ ary -tlle vol~e oC-the
feed chal~ber. This can for e~ample be achieved by connecting
the end wall e~ternal -to -the ~eed chamber to ~ s-tem to which
can be a-t-tached a sui-table actua-tor bu-tton. In this
arrangement, displacement of the actuator bu-tton will also
displace the end wall by way of the connecting stem.
In one embodiment of the inven-tion, -the feed chamber
is a cylinder and the finger displaceable end wall i9 a
pis-ton slidably positioned in the cylinder, the piston being
fitted with a stem carrying an actuator button for finger
displacement.
Associated with the pump is a pressure ac-tuable valve
which is arranged to permit entry of a liquid product to the
feed chamber from an external supply, for example from the
can, bottle or other container to which the pump is attached.
~he valve can, for example, be arrang~d to open to admit
liquid product to the feed chamber during a filling stroke
when the pressure in -the feed chamber falls below that in the
container.
~0 The feed chamber, its finger displaceable end wall
and the pressure actuable valve are so positioned -that downward
axial movement of the ~inger displaceable end wall toward
the valve will reduce the volume of the feed chamber and
increase hydraulic pressure therewithin, and upward axial
movement of the finger displaceable end wall will increase
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~he vo:Lume of the feed chamber and reduce the hydraul:ic
pressure therewi~thin.
The pUlllp iS also provided w:;th an axia'L discharge
cham'ber ~hich is pre-ferably positioned co-axially with
respect to the feed chamber. The discharge chamber is
preferably almular in cross section and where appropriate is
hereina:e-ter referred to as an annular discharge chamber.
The feed chamber and the discharge cha~ber are in
communication with each other so that liquld product can pass
1~ between -them. I~en the discharge chamber is annular in form
at least one radial passageway provides comm~lication between
the chambers, the passageway thus providing a conduit to
enable the liquid product to pass from the ~eed chamber to
the annular,discharge chamber when the hydraulic pressure in
the feed'chamber is increased. This radial passageway can
also function to ensure that the liquid product is thoroughly
mixed within the pump before it is discharged to atmosphere,
by virtue of the shear to which it is subjected as it passes
rapidly from the feed chamber to the annular discharge chamber.
This is particularly valuable where the liquid product to be
dispensed is multiphase or in the form O:r a shearable gel.
A resilient means, for example a spring, is positioned
co~operably with the axial discharge chamber. This resilient
means is capable of storing energy genera-ted by the increase
in hydraulic pressure which results from -the dolYnward movement
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of the finger displaceclble end wall o~ the ~eed challlber. ~en
the resilien-t means is a spring, it can conveniently be
accommodate~ within -the a~ial discharge cham~er or co-axlally
with i-t.
Accor~in~ ~o a preferred e~bodi~en-t of the inven-tion,
the axial discharge chamber houses at least one plunger which
is slidably loca-ted therein together with the spring for
storing energy which functions as the resilient means. The
plunger is resiliently loaded by the spring and is arranged
to move against -the ~orce exerted by the spring when hydraulic
pressure in the axial discharge chamber on -the side remote
from the spring increases.
A discharge conduit is provided to enable the axial
discharge chamber to communicate with the atmosphere e~terior
to the pump, so that liquid product can be discharged when the
pump is actuated. Normally this discharge conduit will be
interrupted at some point be-tween discharge chamber and the
atmosphere and will only provide an uninterrupted pathway
~or the liquid product to be discharged -to atmosphere when
the finger displaceable end wall of the -feed chamber has moved
downwards by a predetermined distance during a downstroke.
Means is accordingly provided for -triggering the
discharge of liquid product at this poi,nt in the downstroke.
This triggering means also releases the energy s-tored in the
resilient means which forces the liquid product out of the
discharge chamber -to atmosphere via the discharge conduit.
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The means for releasing the energy stored in the
resilient means can be provided by -the coincidence of a
passagel~ay interconnecting the axial discharge chamber and
the discharge cond-uit, -the coincidence also permitting liquid
product to exit from the axial discharge chamber -to
atmosphere via a suitable atomising nozzle. The respective
passageway and conduit in this arrangement only come into
coincidence af-ter the end wall of the feed chamber has moved
do~nwardly with respect to the feed chamber -toward the
pressure ac-tuable valve by a predetermined distance.
It is an important feature of the inven-tion that the
finger displaceable end wall forms a liquid tight seal with a
side wall of the feed chamber, at least until the valve means
i9 operated. This is to ensure -that the liquid product under
the influence of increasing hydraulic pressure during a down-
stroke does not prematurely leak past this seal before
opération of the valve means to releace the liquid product
to atmosphere. As soon as the triggering means is operated
and the liquid product dispensed at the end of a downstroke,
there is then no need for the seal between the end wall and
a side wall of the feed chamber to be maintained, although
we have found -tha-t to avoid uneven wear and stress on the
parts maintaining this seal, it is preferable that this seal
~ is also maintained a~ter the valve means has been operated.
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~e ha~c in particular no-ted thal where the feed
chamber and its end wall are cylinder and piston respec-tively,
then wear and tear of the sealing surface of the piston in
particular is negligible, and efi`icjellt dependable trouble-
free operation of the pump during repeated use is more likely
to be the experience of the user than with a pu~p in which
the sealing surface of the piston exits from or in some l~ay
separates from its cylinder at the end of a downs-troke
each time the pump :is actuated.
These as well as other advantages of the pump will
be more fully understood with reference to the accompanying
diagrammatic drawing of which the Figure is a section through
a pump in accordance with the invention.
The p~p as sh~wn in the F'igure consists o~ a
cylindrical outer boày 10 closed at one end by an apertured
pla-te 11, and at the other end by a flange 12 of pump
cylinder 13, which is located co-axially within the outer
body 10.
A finger displaceable piston 1~ having 0 ring seals 30
is slidably positioned in bore 15 of the pump cylinder 13,
the upper end of the piston, i.e. the piston stem, passing
through the apertured plate 11. The piston 14 and the
cylinder 13 together define the feed chamber having a finger
displaceable end wall~ The piston s-tem is hollow to provide
a discharge outlet 16, which communicates with the atmosphere
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via arl ac-tua-ting bu-tton (not shown). ~Tear its lower encl,
-the pis-ton is ~rovided wi-th radial duc-ts 17 (only one of
whicll is shown) through the wall of piston 1~. ~he discharge
outlet 16 ancl radicll ducts 1~ together constitute a discharge
conduit.
The pump cylinde~ 13 also houses a piston return
spring 18 abu-tting lower end 19 of piston 1~ and upper face
of apertured plate 20. This spring biases -the piston towards
-the apertured plate 11 so that pis-ton shoulder 21 abu-ts -the
apertured plate 11. ~he spacer 20 separates the pump cylinder
13 from a non-return pressure-actuable ball valve assembly 22.
The pump cylinder 13 is provided with ~irst radial
passageways 23, two o~ which are shown, interconnecting the
cylinder and annular passageway 24 be-tween ou-ter body 10 and
pump cylinder 13. Annular passageway 24 interconnec-ts radial
passageways 23 and annular chamber 25. ~he annular
passageway and annular chamber together constitute the
annular discharge chamber. It is these radial passageways,
which communicate the annular discharge chamber and the a~ial
feed chamber to provide a conduit for liquid procluct to pass
~rom the feed chamber (i.e. cylinder 13) to the annular
discharge chamber (i.e. annular passageway 24 and annular
chamber 25) when hydraulic pressure in -the ~eed chamber
increases.
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An annular p:Lunger 26 wi-th seals 29 is sl:idably
posi-ti.oned in annular chamber 25 and is ur~ed by a second
spring 27, (i.e. the resilieM-t means for storing energy)
towards annular passage~ay 24. The lower part o-~ -the ~nnular
plunger 26, helow seals 29 as shown in the drawings, is a
loose fit in the annular chamber 25.
The pump cylinder 13 is also provided with second
radial passageways 28 which open into annular chamber 25 and
the bore ].5 of pump cylinder 13. Radial passageways 28 when
in communication with radial ducts 17 constitute the triggering
means for releasing energy s-tored in the spring 27 and means
for conducting liquid produc-t from the annular dischar~e
chamber 24,25 to discharge conduit 16J17. It will be noted
that radial passageways 28 and radial duc-ts 17 are in
communication only af-ter the piston l.~ has moved downwardly
in the bore 15 of cylinder 13 by a predetermined distance.
In the embodiment illus-trated, the cross-sec-tional
area of the annular plunger 26 is 4.6 times that of the
piston end 19.
In use, the pump is applied to the top of a container
of liquid product so that the non-return pressure ac-tuable
ball valve assembly is in contact with the produc-t, if
necessary via a dip-tube (not shown).
As -the first downstroke of pis-ton 14, the first
spring 18 is compressed and air in bore lS is bled via first
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radi~l. passag~ays 23, annular pass~ge~ay 2~, pas.sing annular
plunger 26 to atlllo.sphere ~hen radi.al duc-ts 17 line up with
second radial passageways 28. ~len piston 14 i.s released,
liquid is drawn up through non-return pressure ac-tuable valve
assembly 22 into bore 15.
As -the second downstroke of the piston 14, pressure
within the bore 15 increases and -the liquid is thereby
caused to flow via first radial passageways 23 and annular.
passageway 24 to annular plunger 26. Further increase in
pressure of this liquid displaces the annular plunger 26
upwards against the second spring 27, so that liquid flows
into the annular chamber 25 and strain energy is stored in
the second spring 27. As hydraulic pressure increases still
further, displacement of annular plunger 26 inereases to
accommodate the liquid until radial ducts 17 line up with
second radial passageways 28, thus pro~iding the valve means
for releasing the stored energy, whereupon liquid is
rapidly discharged to atmosphere via discharge outlet 16
in piston 14 and actuator button (not shown).
~s liquid is discharged, decompression of second
spring 27 forces plunger 26 downwards as sho~n in the
drawing and the annular chamber is final.ly sealed -to
atmosphere when finger force applied to -the piston stem via
the actuator button is released,.the piston returning to the
rest position under decompression of first spring 18 and at
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the same time closing second radial passagel~ays 28.
Si~lultan~ously, ~llore liquid product is draw~ i~to the bore 15
via non-return pres~ure actuable valve assembly 22 and -the
discharge and -filling cycle can then be :repea-ted.
I-t will be noted from an inspect-ion of the Figure
that at no time during the downs-troke or the upstroke of the
piston do the O ring seals 30 of the piston leave the confines
of the bore of the cylinder. In view of this, wear of the
O rings is minimal and is in any case less than would be the
case if any of the O rings exited from the bore o`f the
cylinder at any stage during actuation of the pump. It is
also noted that when actuation takes place on completion of
a downstroke, radial duc-t 17 coinciding with radial
passageway 28, the lowermost O ring seal 30, which
effectively seals the piston within the cylinder during a
downstroke, is still in a sealing relationship with the
cylinder.
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The pum-p clispenser according to the invention is
intended to be used for dispensing liquid~ or gels from a
storage chamber which provides a supply of liquid or gel
product external to the dispenser. ~he dispenser can
therefore, for example, be designed for attachment to a
hand held container of a size and capacity similar to a
conventional pressurised pack or aerosol container. It is
also envisaged that the dispen~er can be readily detachable
from its container so that a refill container can be fitted
` 10 when the original container is empty of product.
~he liquid or gel product can be dlspensed as a fine
particulate spray or in any other form in which the product
is not finely-divided, depending on the type of actuator
button which is fitted to the pump dispen~er.
It will be appreciated that the absence of a
liquefied gaseous propellant from the liquid or gel product
as dispensed enables a greater weight of $he product to be
dispensed during a given time. ~`or eYample, a conventional
aerosol hairspray containing about 60,/ by weight propellant
.
~ can, during a 3 second period, dispense as a fine spray
approximately 3 g o$ product onto the hair of the user,
about 2 g of which lS propellant. By way of comparison,
a pump dispenser according to the invention can, in the
absence of propellant, dispense with equal e~ficiercy
~;~` 25~ approximately 1 g of product in the ~orm o~ a finely-diYided
liquid spray during a burst lasting appro~imately 0.5 seconds.
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