CA1096824A

CA1096824A - Dispensing device

Info

Publication number: CA1096824A
Application number: CA215,466A
Authority: CA
Inventors: Rustom K. Gamadia
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1973-12-06
Filing date: 1974-12-05
Publication date: 1981-03-03
Also published as: NL7415900A; JPS5428965B2; BR7410187A; ES432645A1; GB1485767A; PH12810A; AR205178A1; AU7592774A; ZA747689B; NO744409L; JPS50113803A; IT1024989B; AU497320B2; CH590088A5; BE823078A; DE2456843A1; IN141150B; FR2253928A1

Abstract

ABSTRACT OF THE DISCLOSURE A pump dispenser for liquids includes a finger operated piston and cylinger, a valve to allow liquid to enter the pump dispenser during a filling stroke, a chamber to receive said liquid and to store it under increasing hydraulic pressure during a discharge stroke, a spring for storing strain energy as the hydraulic pressure increase, a means for releasing the stored energy when the piston has travelled a predetermined distance relative to its cylinder and a discharge outlet through which liquid is discharged from the chamber as strain energy is released.

Description

~OC'68Z4 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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l~g6824 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 - 5 - /,................................ .

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ilO968Z4 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 ~OC'~!~Z4 ~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 - 7 - /...

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~3"68Z4 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.

~o~6824 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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10~8Z4 ~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 -- ~. 0 ~

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1~96824 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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1~68Z4 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 - 1.2 -~0~68;~4 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 ' ' '1 )96~324 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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~0~6824 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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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A finger-operable pump for dispensing liquids comprising:
a) an axially arranged feed chamber having a finger displaceable end wall, axial movement of which will vary the volume of said feed chamber;
b) a pressure actuable valve to permit entry of a liquid product from an external supply to the feed chamber, said valve and said feed chamber being so positioned that downward axial movement of the finger displaceable end wall toward said valve reduces the volume of the feed chamber and increases hydraulic pressure therewithin, and upward axial movement of the finger displaceable end wall away from said valve increases the volume of the feed chamber and reduces hydrau-lic pressure therewithin;
c) an axial discharge chamber in communication with said feed chamber by means of at least one radial passageway which provides a con-duit for the liquid product to pass between said chambers;
d) a resilient means positioned co-operably with the discharge chamber for storing energy generated by the increased hydraulic pressure which results from downward movement of the finger displaceable end wall with respect to the feed chamber;
e) a discharge conduit communicating the dis-charge chamber with the atmosphere exterior to the pump;
f) means for releasing the energy stored in the resilient means and for conducting the liquid product from the discharge chamber to the discharge conduit, said release means being operable to release the energy and provide a conduit for the liquid product only after the finger displaceable end wall has moved downwardly with respect to the feed chamber by a predetermined distance, the finger dis-placeable end wall forming a liquid tight seal with a side wall of the chamber at least until after said release means is operated.

2. A pump as claimed in claim 1, wherein the axially arranged feed chamber is a cylinder and the finger dis-placeable end wall is a piston slidably positioned in the cylinder.

3. The pump as claimed in claim 1, wherein the pressure actuable valve is a ball valve.

4. The pump as claimed in claim 1, claim 2 or claim 3, wherein the resilient means is a coil spring.

5. The pump as claimed in claim 1, claim 2 or claim 3, wherein the axial discharge chamber houses a plunger resiliently loaded by the resilient means.

6. The pump as claimed in claim 1, claim 2 or claim 3, wherein the cross-sectional area of the axially arranged feed chamber is less than that of the axial discharge chamber.

7. A pump as claimed in claim 1, claim 2 or claim 3, wherein the axial discharge chamber is an annular discharge chamber.

8. The pump as claimed in claim 1, claim 2 or claim 3, wherein valve means for releasing the energy stored in the resilient means is provided by the coincidence of a radial passageway interconnecting the axial discharge chamber and the discharge conduit, said coincidence per-mitting the liquid product to exit from the axial discharge chamber to atmosphere.

9. A finger operable pump for dispensing liquids, the pump comprising:
a) an axially disposed feed chamber including a bore having a constant transverse cross-section and a piston slidable engaged in the bore for movement axially between a rest position and a fully engaged position, the piston being finger operable to move the piston from the rest position to the fully engaged position and defining an outlet conduit extending from a side wall of the piston to a discharge outlet from which the liquid is dispensed;
b) means biasing the piston towards the rest position;
c) an axially disposed discharge chamber defining an opening having a constant transverse cross-section and including a plunger slidably engaged in the opening and moveable axially between a first position in which the chamber has a minimum volume and a second position in which the volume of the chamber has been increased;
d) resilient means biasing the plunger towards the first position; and, e) first and second passageways, said second passageway connecting the discharge chamber to the wall of the bore for carrying liquid from the discharge chamber into the outlet conduit when the piston is in the fully engaged position, and said first passageway being a radial passage-way and connecting the feed chamber to the discharge chamber to permit flow of the liquid from the feed chamber to the discharge chamber upon moving the piston from the rest position to the fully engaged position such that the plunger is driven by displaced liquid from the first to the second position and providing for movement of liquid to permit the end of the piston to move beyond said second passageway until the liquid moves through the second passageway as it travels from the discharge chamber to the outlet conduit under the influence of energy stored in the resilient means.