PRESSURE CONTROL DEVICE FOR PRESSURIZED FLUID CONTAINER AND PRESSURIZED FLUID CONTAINER PROVIDED WITH SUCH A PRESSURE CONTROL DEVICE

Description

The present invention relates to a pressure control device for attachment in a pressurized fluid container separating a dispersible fluid compartment and a propellant compartment, comprising: a partition wall provided with at least one passage opening; and a closing element attached to the partition wall moveable between a passage opening release position and a passage opening closing position. The present invention also relates to a pressurized fluid container provided with such a pressure control device.

Containers for pressurized dispersers fulfil multiple functions, including containing a fluid to be dispersed, and maintaining an overpressure inside the container for dispersing/dispensing of the fluid contained inside the container. In this respect the definition of a fluid is broad; it may be a gas, a liquid, a gel, a paste, a mousse or any type of mixture of such components. A well-known problem with common dispersers is that the pressure at which the fluid to be dispersed is contained, changes over time, due to the leakage of propellant from the container as well as the decreasing level of the fluid to be dispersed because of normal use of the disperser. Although in common household applications-such as personal care products, paint, glue, and so on-a variation in pressure may be acceptable, other applications including the dispersing of high viscous substances such as sealants or caulks, or applications in a medical context, require accurate dosing control. However, in all applications a continuous pressure over the lifetime of the disperser containers is preferred.

To guarantee a constant and predictable outflow of fluid over the lifetime of the disperser, the pressure prevailing in fluid to be dispersed should thus be kept constant. More advanced disperser containers are therefore pressure controlled, for which they are provided with a compartment containing a highly pressurized propellant. The propellant compartment is furthermore provided with a pressure control valve that controls the outflow of propellant from the propellant compartment based on the pressure prevailing in the fluid to be dispersed, thereby keeping the fluid to be dispersed at a constant pressure. Such pressure control devices are known, for instance as disclosed in WO 2018/185652.

The dispersible fluid compartment and the propellant compartment may be embodied as parts (spaces) of a joint mantle (for instance the joint jacket of a spray can) that are separated from each other by a separation wall, in which separation wall the pressure control device is allocated. As an alternative it is for instance also possible that the propellant compartment is a completely enclosed container, which container is placed into or against a dispersible fluid compartment, and wherein the pressure control device is allocated in the wall of an enclosed part of or the fully enclosed (pressurized) container.

The object of the present invention is to provide an improved pressure control device and an improved pressurized fluid container provided with such a pressure control device that provides at least the same functionality as the prior art pressure control devices at for instance lower costs, with less functional limitations and/or with higher functional accuracy.

The present invention provides for this purpose a pressure control device for attachment in a pressurized fluid container separating a dispersible fluid compartment and a propellant compartment, comprising: a partition wall provided with at least one passage opening; and a closing element attached to the partition wall moveable between a passage opening release position and a passage opening closing position; wherein the partition wall is provided with a protruding guide element, wherein the closing element is surrounding the protruding guide element, and wherein the passage opening in the partition wall is allocated in or adjacent the protruding guide element. An outline of the free side of the closing element may be forming the moveable closure of the at least one passage opening in the partition wall. In such pressure control device the closing element gets around (surrounds) the protruding guide element enabling a very compact construction that also requires a limited amount of material compared to the prior art pressure control device. This not only limits material consumption but also limits the price and/or simplifies the construction making the pressure control device less susceptible to malfunctioning and easer to assemble. As the construction is also limited in volume the efficiency of a pressurized fluid container provided with such a pressure control device will also increase compared to the prior art pressurized fluid containers. A further advantage of the limited volume of the pressure control device according to the present invention is that the limited size also enables to put the pressure control device out of the centre of the partition wall (resulting in the pressure control device to be positioned out of the central axis of the pressurized fluid container wherein the partition wall is allocated). As a result of the “out of centre” positioning of the pressure control device in the partition wall a central position in the partition wall is not occupied and may be used to allocate there centrally a valve which may be used for filling the propellant compartment of the pressurized fluid container through the dispersible fluid compartment. This allows the pressurized fluid container to be filled (both with propellant and with dispersible fluid) from one side (the upper side) of the pressurized fluid container, providing the substantial advantage that existing filling equipment may be used without the need of further investments and thus lowers the threshold to switch to the sustainable solution according to the present invention.

The closing element and the protruding guide element are preferably moveable connected such that the closing element and the protruding guide element are gas-tight enclosing a pressure chamber. This gas-tight enclosed pressure chamber when at least partially compressed is exerting a pressure on the inside of the closing element forcing the closing element away from the at least one passage opening, and when the external pressure in the dispersible fluid compartment is not able to withstand the pressure in the pressure chamber, thus opening the aperture in the passage opening in the separation wall, preferably by moving the outline of the free side of the closing element away the at least one passage opening in the partition wall. The result of opening the (at least one) aperture is that propellant will flow from the propellant compartment in the dispersible fluid compartment until the pressure in the dispersible fluid compartment is risen to a level that the closing element is pushed back (against the pressure in the pressure chamber) to the position wherein the closing element seals off the passage opening in the separation wall. A further relevant advantage of the present invention is that any gas pressure dissipation of the pressure in the (in practise not completely gas-tight) pressure chamber with the environment is that this dissipation (limited gas exchange) takes place between the pressure chamber and the propellant compartment (this phenomenon is also referred to as “low-leaking”). Gas will thus not leave the pressure chamber but only a limited volume of gas may flow into the pressure chamber from the propellant compartment over time. The pressure chamber will thus not loose pressure to a level that the pressure control device is not able to open the passage opening anymore; it will due to the minimal leakage result in a (limited) higher pressurised pressure chamber that opens at a higher pressure level. Compared to the prior art pressure control devices this makes the pressure control device according to the present invention more reliable as in the prior art pressure control devices any gas pressure dissipation of the pressure in the (in practise not completely gas-tight) pressure chamber takes place with the dispersible fluid compartment, with an ultimate—and undesired—situation wherein the pressure in the pressure chamber is more or less at the level of the pressure in the dispersible fluid compartment. In this undesired ultimate situation the pressure control device will not open anymore resulting in that a not completely emptied dispersible fluid compartment can no longer be emptied. Such dysfunctioning occurs frequently in practice and is overcome by the present invention.

Preferably the closing element is hood-shaped. Such a simple cap-shaped construction off the closing element is simple to produce, compact and relatively simple to be guided along the protruding guide element. A specific and very simple cup shape is in cross section U-shaped, thus not possessing a border or rim that protrudes from an upright sidewall of the closing element. Even more preferred is that the closing element is circle symmetrical, simplifying the positioning and functioning of the closing element. The hood-shaped closing element is preferably enclosing at least the extremity of the protruding guide element, so that the pressure chamber is allocated between the protruding guide element and the closing element.

In an even more specific embodiment the protruding guide element is surrounded by a slot-shaped channel, which slot-shaped channel may be recessed in the partition wall. The slot-shaped channel is supportive in holding in position of the closing element, especially in the position wherein the closing element is in its passage opening closing position. Furthermore the advantage of the slot-shaped channel surrounding the protruding guide element may limit the height of the protruding guide element required for proper functioning of the pressure control device according to the present invention.

When use is made of a slot-shaped channel the at least one passage opening may well be allocated in the slot-shaped channel. Such will help to protect the passage opening against contamination but even more will help to ensure a correct closing of the passage opening by the closing element. These advantages are even more provided in case the at least one passage opening is allocated in the bottom of the slot-shaped channel.

To ensure a gas-tight moveable contact between the inside of the closing element and the protruding guide element, the inside of the closing element and/or the outside of the protruding guide element may be covered with a flexible sealing material layer. As an alternative also a single material closing element may be used, in which situation the material choice is preferable so that the material of the closing element has sealing properties. For a further improvement of the gas-tight moveable contact between the protruding guide element and the closing element, the inside of the closing element contacting the protruding guide element or the outside of the protruding guide element contacting the closing element may be provided with a (annular) sealing element.

In a simple embodiment the protruding guide element may be cylindrical, thus simplifying the assembly of the pressure control device. As the shape of the closing element and the shape of the protruding guide element are connected to each other also the side of the closing element contacting the protruding guide element will then be cylindrical, and more preferably also the outside of the closing element may then be cylindrical.

For a further stabilisation of the orientation of the closing element during its traveling along the protruding guide element (while moving between a passage opening release position and a passage opening closing position) the protruding guide element may be stationary connected with at least one support that externally seizes on (or guides) the closing element. Such external closing element support may also be provided with an abutment limiting the maximum freedom of movement of the closing element. With such abutment the closing element may not come off the protruding guide element.

The position of the protruding guide element on the partition wall may be chosen as fit in a specific application, for instance may the protruding guide element be centrally located if the partition wall is more or less circular, but as already mentioned before due to the limited size of the closing element according to the present invention the protruding guide element may also be located decentralized in the partition wall.

The invention also provides a pressurized fluid container provided with a pressure control device according to the present invention, wherein the pressure control device is attached in the pressurized container separating a dispersible fluid compartment from a propellant compartment such that the at least one passage opening in the separating wall is the only fluid-permeable connection between the dispersible fluid compartment and the propellant compartment. In this definition the pressurized fluid container thus includes a dispersible fluid compartment, a propellant compartment as well as the pressure control device. In practise the pressurized fluid container will even more also include a disperser nozzle to release the fluid to be dispersed under (the regulated) pressure from the dispersible fluid compartment.

The shape of the pressurized fluid container is free of choice, however in practise cylindrical spray cans are used, which may for instance be made out of aluminium, tin plate material or a plastic like for instance PET. In such cylindrical spray can the partition wall may be disc-shaped, separating the dispersible fluid compartment and the propellant compartment. The propellant compartment may as an alternative also be embodied as an individual container that is placed in a larger dispersible fluid compartment, thus not limiting the shape of the propellant compartment other than that it has to fit within the dispersible fluid compartment and that it can withstand the pressure.

In a specific embodiment of the pressurized fluid container according to the invention the pressure control device may be placed out of the central axis of the pressurized fluid container. As a result of the “out of centre” positioning of the pressure control device in the partition wall a central position in the partition wall is available to allocate there (centrally) a propellant filling valve connecting to the propellant compartment of the pressurized fluid container. This allows the pressurized fluid container to be filled (both with propellant and with dispersible fluid) centrally and from one side (the upper side) of the pressurized fluid container, wherein a longitudinal supply element for the propellant is to be used to make a connection form a propellant buffer outside the fluid container with the valve allocated in the centre of the partition wall of the fluid container. This makes a valve in the bottom superfluous, which supports the solidity of the pressurized fluid container.

The invention will now be elucidated with reference to the non-limitative exemplary embodiments illustrated in the following figures. Corresponding elements are denoted in the figures by corresponding reference numbers. Herein shows:

FIGS. 1A, 1B schematic side views on a pressure control device according to the present invention, wherein the position of a closing element is that is part of the pressure control device is varied;

FIG. 2A a longitudinal cross-section of a bottom part of a pressurized fluid container according to the invention;

FIG. 2B a cross-section through a detailed perspective view of a part of the pressurized fluid container shown in FIG. 2A;

FIG. 3 a cross-section of a pressurized fluid container according to the invention;

FIG. 4A a perspective view of a propellant compartment provided with a part of an alternative embodiment of a pressure control device according to the present invention; and

FIG. 4B a longitudinal cross-section of a an further embodiment of a pressurized fluid container according to the invention incorporating the pressure control device as shown in FIG. 4A.

FIG. 1A shows a pressure control device 1 for attachment in a pressurized fluid container (see FIGS. 2 and 3) having a partition wall 2 that is provided with a surrounding mounting edge 3. In the partition wall 2 a passage opening 4 enables a propellant (normally a gas) to pass the partition wall 2, at least as long as a closing element 5 is not closing off the passage opening 4. In the position of the closing element 5 as depicted in FIG. 1A the closing element 5 is in “a passage opening 4 release position”. The closing element 5 here is hood-shaped and surrounds a protruding cylindrical guide element 6 that is centrally allocated on the partition wall 2, which protruding guide element 6 is surrounded by a slot-shaped channel 7 that is recessed in the partition wall 2. The passage opening 4 is allocated in the bottom of the slot-shaped channel 7. The inside of the hood-shaped closing element 5 is covered with a flexible sealing material layer 8 on the bottom of which sealing material layer 8 an inside annular sealing element 9 (to be compared with an “O-ring”) seals off the contact between the closing element 5 and the protruding guide element 6, thus providing a gas-tight pressure chamber 30 with a volume that is variable due to the movement of the closing element 5 relative to the protruding guide element 6. On the side of the slot-shaped channel 7 facing away from the protruding guide element 6 the partition wall 2 is provided with at least one external closing element guide 9, which external guide element 9 not only externally guides the closing element 5 but also functions as a limitation for the way of trajectory of the closing element 5 (see the abutment 10 on the outer end of the external guide element 9).

In FIG. 1B the pressure control device 1 of FIG. 1A is shown however here the closing element 5 is in the “passage opening closing position” as the closing element 5 is moved (in the figure downwards) in comparison with the position of the closing element 5 in FIG. 1A according the arrow P₁ such that the closing element 5 seals off the passage opening 4. It is also depicted that the volume of the pressure chamber 30 in FIG. 1B is substantially smaller than the volume of the gas-tight pressure chamber 30 in the situation shown in FIG. 1A.

FIG. 2A shows a longitudinal cross-section of the bottom part of a pressurized fluid container 10 provided with a pressure control device 1 according the present invention and as shown in the FIGS. 1A and 1B. The pressure control device 1 is attached in the pressurized container 10 separating a dispersible fluid compartment 11 from a propellant compartment 12 such that a propellant only through the passage opening 4 may flow from the propellant compartment 12 to the dispersible fluid compartment 11, at least as long as the closing element 5 is not in the “passage opening closing position” as depicted in FIG. 2. Also shown is that the pressurized container 10 is provide with an internal annular narrowing 13 (realised buy an external circumferential indention) against which narrowing 13 the wall partition wall 2 with its surrounding mounting edge 3 form-fitting abuts. The connection between the annular narrowing 13 and the surrounding mounting edge 3 of the partition wall 2 is thus medium-tight/gas-tight. For holding the position of the closing element 5 supports 31 are attached such that they are in a stationary position relative to the guide element 6, the supports 31 externally seize on the closing element 5 to keep it in a position that fits the protruding guide element 6. On the side of the guides 31 facing away from the partition wall 2 abutments 32 (stops) are provided ensuring that the closing element 5 will not loosen from the protruding guide element 6.

FIG. 2B shows a cross-section through a detailed perspective view of a part of the pressurized fluid container shown in FIG. 2A wherein the protruding guide element 6 and two protruding guide elements 31 are clearly visible. The closing element 5—that is shown in FIG. 2A—is left out in this figure. Also visible is the passage opening 4 in the partition wall 2. In this embodiment the partition wall 2, the protruding guide element 31 and the supports 31 are all stationary attached to each other. Also reference is made to the abutment 32 that are part of the guides 31 and that prevent the—not shown—closing element 5 from coming loose from the protruding guide element 6.

FIG. 3 shows a perspective external view on the pressurized fluid container 10 of which only the lower part was shown in FIG. 2. A cylindrical shell 20 of the container 10 is provided with an circumferential indention 21 and on the outfeed (upper) side of the container 10 a neck 22 (also referred to as a “dispense valve opening”) and shoulder 23 are applied with a central outlet tube 24 that may be connected to a—not shown here—spray nozzle. The upper side of the pressure control device 1 borders the fluid compartment 11, in which fluid compartment 11 a piston 25. By a movement of the piston 25 towards the outlet tube 24 the fluid in the compartment 11 will be placed under pressure enabling to release a portion of the fluid to be dispersed. The shape of the piston 25 may correspond with the shape of the upper side of the pressure control device 1 and/or the shape of the piston 25 may follow the contour of the closed top of the pressurized fluid container 10 while the piston 25 connects seamlessly but moveable to the inner cylindrical shell wall preventing fluid to pass the piston 25 towards the pressure control device 1, in fact the piston 25 prevents that the dispersible fluid will pass the piston 25.

The pressure control device 1 acts as a constant pressure release valve that opens for gas to pass from the propellant compartment 12 on the opposite side of the pressure control device 1 than the fluid compartment 11.

The propellant compartment 12 functions as a reservoir for a (highly) compressed propellant. Suitable propellants include propane, butane, carbon dioxide, nitrogen, air or any other suitable substance. Preferably, a propellant is chosen that does not chemically react with the dispersible fluid especially when the propellant may contact the dispersible fluid (as may occur in a “diptube” embodiment). The cylindrical shell 20 also comprises a bottom 26. In the depicted case, the cylindrical shell 20 and the bottom 26 are formed as a single, integral part. The bottom 26 is provided with another valve or releasable closing 27, enabling to pressurize the propellant compartment 12.

FIG. 4A shows a propellant compartment 40 that is here not part of a larger construction but that as a “stand-alone” element. The propellant compartment 40 is provided with (here) a part of an alternative embodiment of a pressure control device. Only the protruding guide element 6 is shown (thus not the closing element).

In FIG. 4B the propellant compartment 40 from FIG. 4A is shown in a slightly further amended embodiment that is attached to a dispersible fluid compartment 41. Here also the closing element 5 is shown thus providing an embodiment of a pressurized fluid container 43 according to the present invention. Additionally also a propellant filling valve 44 is shown which is allocated centrally in the pressurized fluid container 43. The central positioning of the propellant filling valve 44 in the fluid container 43 enables to fill the propellant compartment 40 via the—here in an already closed off situation depicted—central upper opening 46. The propellant filling valve 44 here shown is an umbrella valve 44 comprising a flexible head 47 (e.g. made out of silicone) that enables distortion for passage of a propellant that is brought in via a propellant filling opening 48. Tit will be clear that a central propellant filling valve 44 may also be practised in for instance an embodiment of the pressurized fluid container 10 partially shown in the FIGS. 2A and 2B wherein the pressure control device 1 is allocated decentrally.