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(11) | EP 0 639 149 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
DISPENSING APPARATUS UTILIZING A PRESSURE GENERATOR ABGABEVORRICHTUNG MIT EINEM DRUCKERZEUGER APPAREIL DISTRIBUTEUR METTANT EN OEUVRE UN GENERATEUR DE PRESSION |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a pressure generator and, more particularly to a dispensing apparatus utilizing such a pressure generator for dispensing product from sealed containers.
[0002] Aerosol pressurized dispensers have become familiar, if not essential, products in both consumer and industrial use due to the efficient way in which they discharge a myriad of products.
[0003] A common example is the hair spray dispenser in which, inside the dispenser, the product spray is dispersed in and surrounded by a liquefied propellant gas under pressure forming a uniform, single phase measure of the product spray and the liquefied propellant. As the product release valve is pressed, the liquefied propellant immediately vaporizes forcing the product spray out of the dispenser in the form of a fine mist.
[0004] A second type of aerosol dispenser, the cheese spread dispenser being a common example, discharges the product, not as a fine mist, but as a solid. In this second category of aerosol dispensers, the propellant exists within the dispenser as a gas and does not mix with the product. Rather, it forms a separate layer over the product to be discharged. As the product release valve is pressed, the propellant, being under pressure, pushes the product out of the dispenser.
[0005] The most commonly used propellants are butane, nitrogen and chlorinated fluorohydrocarbons (CFC's), such as those sold under trade name of Freon. CFC's and butane are often preferred over nitrogen since their vapor pressures are independent of the volume of free headspace in the dispenser. Thus, as long as some of the CFC or butane is present in the dispenser, the pressure exerted on the product is virtually constant throughout the discharge life of the system.
[0006] However, both CFC's and butane have adverse effects on the environment. CFC's add to the destruction of the earth's protective ozone layer which has lead the world community to seek a complete ban of CFC usage. Many countries have already banned its use or have implemented programs and schedules designed to eliminate CFC usage in the near future. Butane, on the other hand, is extremely flammable, making storage, handling and use of butane charged containers very hazardous. In addition, butane contaminates the flavor and smell of the dispensed product, thereby further restricting its use.
[0007] Although nitrogen is available as a substitute propellant, its vapor pressure is such that as product is dispensed, the propellant pressure decreases. Therefore, the product cannot be dispensed at a constant pressure through the life of the product, and at some point, the propellant pressure will fall below that needed to propel any product from the dispenser. To enable all of the product to be dispensable, the nitrogen must be pressurized to dangerously high levels increasing the risk of rupture or requiring more costly dispenser construction.
[0010] Canadian Patent Application CA-A-2013636 discloses an apparatus according to the pre-characterising part of claim 1. However, in such apparatus the piston member is not physically retained axially in the cylinder member.
[0011] An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a front elevational view, partially in section, showing a dispensing apparatus which is not an embodiment of the present invention but which is included to assist in understanding the embodiment;
Figs. 2A and 2B are enlarged sectional views of the pressure generator of the apparatus of Fig. 1 shown in different operating modes;
Fig. 3 is an enlarged sectional view of an alternative piston for use in the pressure generator of Figs. 2A and 2B; and
Fig. 4 is a view similar to Fig. 1 of the embodiment of the dispensing apparatus of the present invention.
[0012] Referring to Fig. 1 of the drawings, the reference numeral 10 refers in general to a container, or can, containing a product 12 and a pressurized headspace 14. The container 10 is formed by a cylindrical wall closed at its lower end by a bottom plate 18 and at its upper end by a cap 20. It is understood that the container 10 can be an aerosol can, a vat, a beer or beverage keg, a storage vessel, a bottle or any other type of container used for the storage and dispersement of a product and can have any desired shape or configuration.
[0013] The cap 20 has a raised central portion 20a which receives a valve 22. A hollow actuating stem 24 extends from the valve 22 and through an opening formed through the raised cap portion 20a and receives a hollow push button 26. A tube 28 is disposed in the container 10 in a coaxial relationship therewith. The lower end of the tube 28 is slightly spaced from the bottom plate 18 and the upper end extends into the valve 22. The valve 22 is normally closed but when the push button 26 is manually pushed downwardly, the valve opens to connect the tube 28 with the stem 24. This permits the product 12 in the container 10 to flow through the tube 28, the valve 22, the stem 24 and to the push button 26 from which it discharges outwardly through discharge openings in the push/button, as will be explained. Since these components are conventional they will not be described in any further detail.
[0014] A pressure generator for pressurizing the headspace 14 is disposed in the container 10, and is referred to in general by the reference numeral 30. Referring to FIG. 2A, the pressure generator 30 is formed by a vessel 32 having a closed lower end portion and an upper end which narrows to form a shoulder 32a and a neck 32b which defines an opening 32c. The neck 32b is adapted to receive a plug 34 having a continuous bore 34a extending therethrough. The neck 32b is pliable and the diameter of the plug 34 slightly larger than the opening 32c, such that the plug 34 press fits into the bore 34a, slightly deforming the neck 32b.
[0015] A cylinder 36 is disposed in the vessel 32 and has a closed lower end and an open upper end. The upper end is integrally connected to the shoulder 32a of the vessel 32 by welding or the like. The diameter and the length of the cylinder 36 are less than the diameter and length, respectively, of the vessel 32 to define a high pressure chamber 38.
[0016] An opening 36a is provided through the wall of the cylinder 36 and a notch, or groove, 36b is formed in the inner surface of the cylinder 36 and extends above the opening 36a, for reasons to be described. A piston 40 operates within the cylinder 36, the outer diameter of the piston 40 being slightly less than the inner diameter of the cylinder 36 to permit reciprocal movement of the piston 40 in the cylinder 36 and to define a flow passage therebetween. Two axially spaced annular grooves are provided near the respective ends of the piston 40 and receive two sealing members, preferably in the form of O-rings, 42 and 44. The cross-sectional area of the O-ring 42 is less than that of the corresponding cross-sectional area of the notch 36b, for reasons to be described.
[0017] A pre-pressure chamber 46 is defined between the respective lower ends of the piston 40 and the cylinder 36 which is pressurized to urge the piston 40 upwardly, as will be described. A spring 48 extends in the chamber 46 which also urges the piston 40 upwardly. In the position shown in FIG. 2A, the piston 40 is in its upper position in which its upper end engages the plug 34, thereby preventing any further upward movement of the piston 40.
[0018] Before operation, the chambers 38 and 46 of the vessel 32 are charged to respective predetermined pressures with a quantity of inert gas such as air, nitrogen, nitrous oxide, carbon dioxide or the like. The chamber 46 is charged to a pressure that is approximately equal to the pressure found in the headspace 14 needed to propel the product 12 from the container 10. The chamber 38 is pressurized to a greater pressure than the chamber 46 to recharge the headspace 14 as is described below.
[0019] To charge the chamber 46, the piston 40 is moved downwardly such that the upper O-ring 42 is below the opening 36a of the cylinder 36. Then, pressurized gas is introduced from the opening 32c of the vessel 32 through the bore 34a of the plug 34, which gas passes through the opening 36a of the cylinder 36 and into the chamber 38. Once the pressure in the chamber 38 reaches a predetermined level, the plug 34 is removed and the piston 40 is raised such that the lower O-ring 44 is above the opening 36a of the cylinder 36 to allow the gas to pass through the opening 36a and fill the chamber 46. The piston 40 is then lowered to the position shown in FIG. 2A such that the lower O-ring 44 is below the opening 36a to seal the gas in the chamber 46. The piston 40 is prevented from ejecting from the cylinder 36 by the reinsertion of the plug 34, or as shown in FIG. 2B by the neck 32b of the vessel 32 which is folded down to partially block the opening 32c.
[0020] To charge the chamber 38, the piston 40 is further lowered such that the upper O-ring 42 is below the opening 36a of the cylinder 36. Additional pressurized gas is then introduced from the opening 32c through the bore 34a, which additional gas passes through the opening 36a of the cylinder 36 and into the chamber 38.
[0021] The introduction of this additional gas is continued until the chamber 38 is pressurized to the predetermined level. Thereafter, the piston 40 is allowed to be urged to the position shown in FIG. 2A where the upper end of the piston 40 engages the plug 34. In this position, the upper O-ring 42 engages corresponding portions of the inner wall of the cylinder 36 to seal against the flow of the pressurized gas contained in the chamber 38 out of the vessel 32 and into the container 10 via the space between the piston 40 and the cylinder 36; while the lower O-ring 44 seals against the flow of gas to and from the chamber 46. While in this position, the pressure generator 30 can be moved and transported without accidentally depressurizing either of the chambers 38 or 46.
[0022] After the chambers 38 and 46 are charged, the pressure generator 30 is placed in the container 10 which contains the product 12 to be dispensed, and the headspace 14 in the container 10 is charged to a predetermined pressure with a gas similar to the gas used to charge the chambers 38 and 46 of the vessel 32, which pressure is selected to be initially greater than the combined force exerted on the piston 40 by the gas and the spring 48 in the chamber 46. After the container 10 is sealed off, or closed, the pressure in the container 10 acts through the opening 32c of the vessel 32 via the bore 34a of the plug 34 on the upper end of the piston 40 to force it downwardly to the operating position shown in FIG. 2B. In this operating position, both O-rings 42 and 44 engage the inner wall of the cylinder 36 to prevent any flow of the pressurized gas through the cylinder 36, and the upper O-ring 42 extends between the opening 36a and the notch 36b.
[0023] The piston 40 remains in the position shown in FIG. 2B until the container 10 is used by manually pressing the push button 26, in which case the pressure in the headspace 14 of the container 10 propels the product 12 through the tube 28, the valve 22, the stem 24 and outwardly through the openings in the push button 26. This causes the pressure in the container 10 to decrease until the pressures exerted on the lower end of the piston 40 by the pressurized gas in the chamber 46 and the spring 48 (if present) are greater than the corresponding pressure acting on the upper end of the piston 40 by the pressurized product 12 in the container 10. Upon this occurring, the piston 40 moves upwardly until the upper O-ring 42 extends in the notch 36b of the cylinder 36. This permits the high pressure gas in the chamber 38 to pass through the opening 36a, through the space between the outer surface of the piston 40 and the inner surface of the cylinder 36, through the notch 36b and outwardly through the upper opening 32c of the vessel 32.
[0024] The pressure in the container 10 is thus increased accordingly until the pressure exerted thereby on the upper end of the piston 40 is sufficient to overcome the pressure exerted on the lower end of the piston 40 by the spring 48 and the pressure in the chamber 46. At this point, the piston 40 will move back to the position shown in FIG. 2B thus blocking any further flow of high pressure gas from the chamber 38 into the container 10 as described above. Note however, that should the pressure in the container 10 quickly drop a significant amount, such as due to a leak, the pressure in the chamber 46 will force the piston 40 against the plug 34 (or the folded down neck 32c), thereby sealing the high pressure gas in the chamber 38 by the upper O-ring 42.
[0025] This back-and-forth movement of the piston 40 relative to the cylinder 36 continues in the manner described above as the product 12 is periodically dispensed from the container 10. As a result, a constant pressure will be available in the container 10 at all times to propel the product 12 from the container 10, while the propellant utilized can be an inert gas which is not harmful to the environment.
[0026] To facilitate the previously described charging of the chambers 38 and 46 of the pressure generator 30, an alternative piston 40' may be disposed in the cylinder 36. The piston 40' is shown in FIG. 3 and has two axially spaced annular grooves provided near its ends for receiving the O-rings 42 and 44. Upper and lower wells 50 and 52 having annular flanges 50a and 52a are provided in the upper and lower ends of the piston 40', respectively, for receiving a tool (not shown), such as a spheric pen, to axially position the piston 40' during charging of the chambers 38 and 46. Otherwise, the operation of the piston 40' is identical to that of FIGS. 2A and 2B.
[0027] Referring to FIG. 4. an embodiment of the present invention is shown in which the reference numeral 92 refers in general to a container for containing and dispensing a product. The container 92 is formed by a cylindrical wall 94 closed at its lower end by a bottom plate 96 and at its upper end by a cap 98. It is understood that the container 92 can be an aerosol can, a vat, a beer or beverage keg, a storage vessel, a bottle or any other type of container used for the storage and dispersement of a product and can have any desired shape or configuration.
[0028] A pipe 100 registers with and extends from an opening 98a in the cap 98. The pipe 100 branches into two branches 100a and 100b for passing product from the container 92 to two dispensing containers 102 and 104, respectively.
[0029] A pressure generator for pressurizing the container 92 is referred to in general by the reference numeral 106. The pressure generator 106 is formed by a cylindrical vessel 108 having a closed upper end and a lower end having a neck 108a which defines an opening 108b. The neck 108a is adapted to receive a cannulated plug (not shown) similar to the plug 34 previously described. In a preferred embodiment, the neck 108a is pliable and can be folded down to partially block the opening 108b, as is shown in FIG. 4.
[0030] The outer diameter of the vessel 108 is slightly less than the inner diameter of the container 92 to permit reciprocal movement of the vessel 108 in the container 92. Two axially spaced annular grooves are provided near the respective ends of the vessel 108 and receive two sealing members, preferably in the form of O-rings, 110 and 112.
[0031] A gas chamber 114 is defined between the lower end of the vessel 108 and the bottom plate 96 of the container 92 and a further chamber 113 for containing product is defined above the vessel 108. To urge the vessel 108 upwardly for reasons described below, the chamber 114 is pressurized through an opening 96a in the bottom plate 96 which is sealed with a rubber valve 116.
[0032] A cylinder 118 is disposed in the vessel 108 and has a closed upper end and an open lower end. The lower end is integrally connected to the lower end of the vessel 108 in alignment with the opening 108b by welding or the like. The diameter and the length of the cylinder 118 are less than the diameter and length, respectively, of the vessel 108 to define a high pressure chamber 120.
[0033] A piston 122 operates within the cylinder 118 and defines a pre-pressure chamber 124. The cylinder 118 and the piston 122 are identical to the cylinder 36 and the piston 40 of FIGS. 2A and 2B, and thus will not be described in further detail. Again, the spring 48 has not been shown for the convenience of presentation.
[0034] Before operation, the chambers 120 and 124 of the vessel 108 are charged to respective predetermined pressures with a quantity of inert gas such as air, nitrogen, nitrous oxide, carbon dioxide or the like. In a preferred embodiment, the chamber 124 is charged to a pressure that is equal to the pressure needed in the containers 102 and 104 to propel product from the containers 102 and 104 at a predetermined flow rate. The chamber 120 is pressurized to a greater pressure than the chamber 124 to recharge the pressure in the chamber 114 as will be described. Since the methods of charging the chambers 120 and 124 are identical to the methods of charging the chambers 38 and 46 of FIGS 2A and 2B, they will not be discussed here in detail.
[0035] After the chambers 120 and 124 are charged, the pressure generator 106 is placed in the container 92 in the orientation shown in FIG. 4. The chamber 113 is then filled with product, and the chamber 114 charged via the valve 116 to a predetermined pressure with a gas similar to the gas used to charge the chambers 120 and 124. The pressure in the chamber 114 is selected to be initially greater than force exerted on the piston 122 by the gas in the chamber 124 and any spring present therein. The pressure in the chamber 114 thus acts through the opening 108b of the vessel 108 on the lower end of the piston 122 to force it upwardly to its operating position as previously described in connection with FIGS. 2A and 2B.
[0036] When product is dispensed from either of the containers 102 or 104, the pressure in the containers 102 and 104, and therefore in the container 92, is decreased. This causes the vessel 108 to rise upwardly in the container 92 to equalize the pressures in the chamber 114 and in the containers 92, 102 and 104. The upward movement of the vessel 108 decreases the pressure in the chamber 114 and thus the force exerted on the lower end of the piston 122. Upon this occurring, the piston 122 is forced downwardly by the pressure in the chamber 124, thereby releasing pressurized gas from the chamber 120 as described in connection with the embodiment of FIGS. 2A and 2B.
[0037] The pressure in the chamber 114 is thus increased, which accordingly urges the vessel 108 to rise further within the container 92 which accordingly increases the pressure in the containers 92, 102 and 104. The release of the pressurized gas from the chamber 120 continues until the pressure in the containers 92, 102 and 104 and in the chamber 114 is equal to the pressure in the chamber 124. At this time, the piston 122 will move back to its blocking position.
[0038] This back-and-forth movement of the piston 122 relative to the cylinder 118 and the upward movement of the vessel 108 within the container 92 continues in the manner described above as product is periodically dispensed from the containers 102 and 104. As a result, a constant pressure will be available in the containers 102 and 104 at all times to propel product from the containers at a constant flow rate, while the propellant utilized can be an inert gas which is not harmful to the environment. Further, the propellant gas is separated from the product to prevent any contamination.
[0039] It is thus seen that the dispensing apparatus of the present invention provides several advantages, not the least significant of which is that it provides a dispenser capable of dispensing a product at a substantially constant pressure throughout the life of the product without having to use an environmentally hazardous propellant, the intended propellants being air, nitrogen, nitrous oxide, carbon dioxide and the like. In fact, in the embodiment shown in FIG. 4, a dispensing apparatus is disclosed which does not discharge any propellant into the atmosphere. The present invention also enables a precise, constant pressure to be simultaneously maintained in numerous discharge vessels by the utilization of a single pressure generator in a common storage container, as is described in connection with FIG. 4.
[0040] The pressure generator of the present embodiment is also easily assembled due to the few components required and the simplicity of those components. Further, the pressure generator requires no manual actuation before or during use.
[0041] It is understood that variations may be made in the foregoing without departing from the scope of the present invention. For example, the pressure in the pre-pressure chamber 124 can be provided by high pressure gas alone, by a spring 48 alone, or by the combination of both.
[0042] In fact, external charging of the pre-pressure chamber 124 or the use of a spring 48 can be avoided altogether by the appropriate dimensioning of the cylinder 118. For example, as the pressure generator 106 is assembled, the air already present in the cylinder 118 is compressed by the insertion of the piston 122. Therefore, the cylinder 118 and the piston 122 can be appropriately dimensioned such that as the piston 122, moves to its operating position an shown in FIG. 2B, the air present in the chamber 124 is compressed to the desired pre-pressurized level.
[0043] The components of the pressure generator of the present embodiment have been primarily described and shown in the drawings as being metal. These components, however, such as the vessel, the cylinder and the piston, can be metal (preferably aluminium), plastic (preferably polyoxymethalene or polyethelene terephthalate), or any other like material. In addition, the O-rings 42, 44, 110 and 112 can be replaced with other types of movable seals such as quadring, rings, scrapers and the like, which can either be separate from the other components or jointly molded thereon. For example, a piston formed of plastic may have annular ridges formed thereon to provide the needed sealing and reciprocal movement within the cylinder.
a container (92),
a vessel (108) containing pressurized gas and disposed in the container (92), and
means responsive to a reduction of gas pressure in the container (92) for permitting the pressurized gas in the vessel (108) to pass from the vessel to the container to maintain the substantially constant predetermined pressure in the container, such means comprising:
a cylinder member (118) disposed in the vessel (108) and defining with the vessel a first chamber (120) for containing the pressurized gas,
a piston member (122) disposed in the cylinder member (118) and defining with the cylinder member a second chamber (124), one of the piston and cylinder members being exposed to the pressure in the container (92) for moving to a first position relative to the other member in which position the pressure in the container equals the predetermined pressure,
means (48) including a pressurized gas in the second chamber (124) for moving the one member to a second position relative to the other member in response to the pressure in the container (92) decreasing below the predetermined pressure, and
connecting means (36a, 36b, 42) responsive to the one member moving to the second
position for connecting the first chamber (120) with the container (92) to permit
the pressurized gas to pass from the first chamber (120) to the container, the connecting
means being responsive to the one member moving to the first position for disconnecting
the first chamber (120) from the container to prevent the passage of the pressurized
gas, thereby to maintain the substantially constant predetermined pressure in the
container,
wherein the vessel (108) is disposed in the container (92) so as to divide the container
into a third chamber (113) for containing the product and a fourth chamber (114) for
containing gas at a predetermined pressure, the vessel (108) being movable in the
container in response to a reduction of pressure in the third chamber (113) as the
product is dispensed such that the volume of the third chamber reduces and the volume
of the fourth chamber (114) increases, such movement reducing the pressure of the
gas in the fourth chamber (114), and
wherein the connecting means (36a, 36b, 42) permits the pressurized gas in the vessel
(108) to pass from the vessel only to the fourth chamber (114) to maintain the predetermined
pressure in the fourth chamber,
characterised in that:
neck means (108a) are provided extending from an end of the cylinder member (118) such neck means permitting the piston member to initially project from the cylinder member so that the second chamber (124) can be charged with the pressurized gas, the neck means (108a) being adapted to thereafter partially block such end of the cylinder member (118) to retain the piston member (122) axially within the cylinder member.
ein Container (92),
ein Behälter (108) der Druckgas enthält und im Container (92) gestellt wurde, und
Vorrichtung verantwortlich für eine Erniedrigung des Gasdrucks im Container (92) um den Fluß des Druckgases im Behälter (108) zu erlauben zwischen den Behälter zum Container um den wesentlich unveränderlichen Druck im Container zu behalten, und diese Vorrichtung umfaßt :
ein Zylinder (118), abgestellt im Behälter (108) und der mit dem Behälter eine erste Kammer (120) für die Lagerung des Druckgases bestimmt,
ein Kolbenglied (122), abgestellt im Zylinderglied (118) und der mit dem Zylinderglied eine zweite Kammer (124) bestimmt, wobei ein der Kolben- und Zylinderglieder am Druck im Container (92) ausgesetzt wird um zum ersten Stand bezüglich des andern Glieds zu bewegen, zum Stand in dem der Druck im Container dem voreingestellten Druck ähnlich ist.
Vorrichtung (48), einschließlich eines Druckgases in der zweiten Kammer (124) um das eine Glied im Vergleich zum zweiten Glied zum zweiten Stand zu bringen, um den Druck im Container (92) unter dem voreingestellten Druck zu erniedrigen, und
Verbindungsvorrichtungen (36a, 36b, 42) die reagerieren mit dem ersten Glied, das zum zweiten Stand bewegt um die erste Kammer (120) mit dem Container (92) zu verbinden, damit das Druckgas von der ersten Kammer (120) zum Container laufen könnte, und wobei die Verbindungsvorrichtungen reagieren auf das zum ersten Stand für die Abschließung der ersten Kammer (120) bewegende Glied, damit der Fluß des Druckgases vorgebeugt wird, und wobei im Container ein wesentlicher unveränderlicher voreingestellter Druck einbehalten wird.
In diesem Container (92) wird Behälter (108) abgestellt, damit der Container in einer
dritten Kammer (113) verteilt wird für die Lagerung des Produkts und in einer vierten
Kammer (114) um Gas in einem voreingestellten Druck zu lageren, wobei der Behälter
(108) im Container bewegt zufolge einer Erniedrigung des Drucks in der dritten Kammer
(113) durch den Austrieb des Produkts, derweise, daß das Volumen der dritten Kammer
abnimmt und das Volumen der vierten Kammer erhöht, wobei diese Bewegung den Druck
des Gases in der vierten Kam mer (114) verringert, und
wobei die Verbindungsvorrichtung (36a, 36b, 42) dem Druckgas im Behälter (108) erlaubt
vom Behälter nur zur vierten Kammer (114) zu fließen um in der vierten Kammer den
voreingestellten Druck zu behalten,
gekennzeichnet durch :
Halsvorrichtungen (108a) ragen von einem Endteil des Zylinderglieds (108) hinaus, wobei derartige Halsvorrichtung das Kolbenglied erlaubt beim Anfang aus dem Zylinderglied vorzuspringen damit die zweite Kammer (124) mit dem Druckgas geladen werden kann, und wobei die Halsvorrichtung (108a) abgeändert wird um nachher dieses Endteils des Zylinders (118) teilweise zu blockieren um die Kolbe (122) axial mit dem Zylinderglied zu halten.
un conteneur (92),
une nacelle (108) contenant du gaz sous pression et déposée dans le conteneur (92), et
des moyens répondant à une réduction de la pression du gaz dans le conteneur (92) pour permettre le gaz sous pression dans la nacelle (108) de passer de la nacelle au conteneur pour maintenir la pression substantiellement constante dans le conteneur, les dites moyens comprenant :
un moyen cylindre (118) déposé dans une nacelle (108) et définissant avec la nacelle une première chambre (120) pour contenir du gaz sous pression,
un membre piston (122) déposé dans le moyen cylindre (118) et définissant avec le moyen cylindre une seconde chambre (124), une des membres du piston et du cylindre étant exposée à la pression dans le conteneur (92) pour bouger à une première position relative à l'autre moyen ; position dans laquelle la pression dans le conteneur égale la pression prédéterminée.
des moyens (48) incluant un gaz sous pression dans la seconde chambre (124) pour bouger l'un moyen à une seconde position relative à l'autre moyen en réponse à la pression dans le conteneur (92) diminuent en dessous de la pression prédéterminée, et
des moyens de connexion (36a, 36b, 42) répondant au moyen qui bouge vers la seconde
position pour connecter la première chambre (120) au conteneur (92) pour permettre
le gaz sous pression de passer de la première chambre (120) dans le conteneur, les
moyens de connexion répondant au moyen qui bouge vers la première position pour déconnecter
la première chambre (120) du conteneur pour ainsi éviter le passage du gaz sous pression
et maintenant ainsi la pression substantiellement constante dans le conteneur,
caractérisé en ce que la nacelle (108) est déposée dans le conteneur (92) pour diviser
le conteneur dans une troisième chambre (113) pour recevoir le produit et une quatrième
chambre (114) pour contenir du gaz à une pression prédéterminée, la nacelle (108)
étant meuble dans le conteneur en réponse à une réduction de la pression dans la troisième
chambre (113) au moment où le produit est dispensé ainsi que le volume de la troisième
chambre se réduit et que le volume de la quatrième chambre (114) augmente, le dit
mouvement réduisant la pression du gaz dans la quatrième chambre (114), et
caractérisé en ce que les moyens de connexion (36a, 36b, 42) permettent le gaz sous
pression dans la nacelle (108) de passer de la nacelle rien qu'à la quatrième chambre
(114) pour maintenir la pression prédéterminée dans la quatrième chambre,
caractérisé en ce que :
un moyen coude (108a) est prévu s'étendant d'une partie du moyen cylindre (118), le dit moyen coude permettant le moyen piston de projeter initialement du moyen cylindre ainsi que la seconde chambre (124) peut être chargée de gaz sous pression, le moyen coude (108a) étant adapté pour après partiellement bloquer la dite partie du moyen cylindre (118) pour retenir le moyen piston (122) de manière axiale dans le moyen cylindre.