AEROSOL DISPENSER WITH AIR VENT PASSAGES ADAPTED TO BE SEALED The present invention relates to an aerosol dispenser of the "isolation" type in which a pressurized, gaseous or gasifiable liquid propellant is held in a container that is mounted within but is otherwise separate from a container for a fluent product to be dispensed, and in which the propellant and the product are isolated from one another until mixed at or near a discharge port, in the course of discharge .
In a known form of such dispensers, a valve located in the head structure of the dispenser normally prevents outflow of the pressurized propellant but, on being opened, permits flow of propellant in gaseous (vapour) form to the discharge port* By the action of an ejector (sometimes called a "venturi") near the discharge port, to which separate flow lines from the product container and the propellant container are respectively connected, the outflow of the propellant when the valve is open reduces the pressure in the produc flow line and a simultaneous outflow of the product is brought abou o By suitably directing the stream of propellant with respect to the stream of fluent product, atomization of the product commonly is effected and a spray discharge is produced,, Such a device is described Israel Patent Application No, 25655») in some detail in / ^%« -¾ e^e^^'f¾>i^- 4¾-e^-y- Sorie-1—tte-r -^] @e^ -^3re4-#a»»a3?y-ee7--"9^6-s Therein is described a dispenser unit comprising a propellant container, a valve unit having separate product and propellant passages, and a valve operating button having an ejector and discharge orifice for effecting a spray of product.
This unit is fitted within an outer product container,, A product flow line extends from the discharge orifice in the button through the propellant container and terminates in a product eduction tube which extends through and out of the propellant container for immersion in the produc „ After assembly and charging of the propellant container, it is slipped into the open mouth of a product-filled outer container. The mouth opening is designed to accept and to secure the propellant container in a nested position, thereby closing the mouth of the product container to provide a unitary package for dispensing the product 0 Isolation of the product from the propellant avoids problems of incompatibility of product and propellant and permits aerosol dispensing of products previously considered impracticale Furthermore, the separate product container may be manufactured in unlimited shapes from non-rigid materials J such as plastics, since the product container is not pressurizedo Since the product within the outer container is fluent, a close fitting seal must be provided between the product container mouth opening and the exterior surface of the propellant container to prevent product leakage „ The insertion of the propellant container into the product container displaces air or gas within the product container by virtue of the piston effect of the descending propellant containere The necessarily close fit between the propellant container and the mouth of the product container prevents the escape of this displaced air and results in a pressure rise within the product container,, This pressure rise may distort the product container, if it is flexible, or may force the product to ascend the open product flow line and cause the product to leak from the discharge orifice of the valve actuating dispenser button, An object of the present invention is to provide a means for venting displaced air from the product container of a pressurized dispenser of the "isolation" type.
The present invention comprises an aerosol dispenser of the type in which a propellant container is mounted with an interference fit in an outer container for a product to be dispensed, characterised by the fact that in at least one of the contacting surfaces that form the interference fit there is provided an air vent passage or passages which allow escape of air as the propellant container is being inserted into the product container, said passage or passages being sealed during or at the final part of the insertion movement* "by the engagement of cooperating parts of both containers.
In the accompanying Drawing: Figure 1 is a vertical cross-sectional view of one form of aerosol dispenser according to the present invention Referring now to the drawing, Pig0 1 shows an assembled dispenser with a propellant container or cartridge secured in the mouth of an outer product container 10. The propellant cartridge includes a propellant chamber 20 which is supplied with a pressurized, preferably gasifi-able liquid propellant 25 which usually is a fluorinated-chlorinated hydrocarbon of the type sold under the Trade Marks G-enetron and Freon,, The propellant chamber 20 is closed by a conventional valve mounting cup 26 which is secured by crimping to the chamber 20 by a conventional rolled seam 2 „ A valve mounting pedestal 27 is formed in the central portion of the valve mounting cup 260 A propellant valve assembly 30 is secured to the valve mounting pedestal 27 by conventional crimping techniques. The propellant-valve assembly 30 comprises a valve housing 35 with an inner valve body 37 which is biased upwardly by virtue of the elasticity of a plastic tube 29 which serves as a portion of the product flow line0 A resilient annular valve member 33 surrounds the valve stem 31 which is integral with the valve body 37- The resilient member 33 closes a valve orifice 36 which communicates a passage 38 in the interior of the valve stem 31 with the propellant vapour phase in the interior of the propellant chamber 20e A valve actuating dispenser button 40 is secured to the upper end of valve stem 31 with a passage 44 in communication with the propellant passage 38 of the valve stem.
Parallel to the propellant passage 38 of the valve stem 31 is a product passage 39 which extends through the valve body 37 to communicate with a product flow line 290 The product flow line 29 passes through the propellant chamber 20 and exits through a seal 23 in the bottom of the chamber 20 „ A flexible dip tube 9 is affixed to the chamber 20 and is in communication with the product flow line 290 The upper end of the product passage 39 communicates with a passage 43 in the valve actuating dispenser button. An ejector passage 41 within the button communicates with both the propellant passage 44 and the product passage 43 and extends to a discharge orifice 42 on the exterior of the button e In operation, manual downward force on the valve actuating button 40 causes depression of the valve body 37 against the spring effect of the tube 29 » Such motion causes the resilient sealing member 33 of the valve to "peel back" to expose the orifice 36 to the propellant pressure available in the propellant chamber 20 „ Propellant vapour then rushes through the orifice 36 and up the propellant passage 38 of the valve stem 31 to the propellant passage 44 of the actuator buttonD The propellant vapour thus released traverses the ejector passage 41 of the button to exit from the discharge orifice 42 with an appropriate velocity0 The velocity of the moving stream of propellant gas across the terminal end of the product passage 43 of the button 40 causes a reduction in pressure throughout the product flow line which causes product 7 to be sucked through the product flow line 2 9 from the product container 10 0 The product thus educted from the container is dispensed from the discharge orifice 42 as a spray o At the conclusion of a spray cycle, the pressure within the product container 10 is restored to that of the atmosphere by virtue of the unrestricted communication of the product flow line 29 with the atmosphere through the ejector passage 41 o In the embodiment illustrated in Fig0 1 , the mouth 8 of the product container 10 is provided with an annular shoulder 11 which is adapted to receive a rolled bead 21 formed in the wall of the propellant cartridge 20 » When the cartridge 20 is inserted in the mouth 8 , shoulder 11 and bead 21 cooperate to support the cartridge within "the mouth o Adequate frictional retention and lateral support of the propellant cartridge 20 in the product container is assured by a wall 13 in the container mouth which is dimensioned to be an interference fit with the cylindrical wall 22 of the propellant cartridge0 In order to vent displaced air9 grooves 12 are formed in the interior surface of the mouth of the product container 10o These grooves extend from the interior of the product container 10 to a point above the annular shoulder 11, A second annular shoulder 15 is provided near the entrance of the mouth to receive the edge of the rolled seam 24 of the mounting cup 260 This second shoulder further supports the cartridge 20» When the propellant cartridge is inserted into the mouth of the product container, a quantity of air equal to the included volume of the propellant cartridge ia necessarily displaced0 To prevent a build-up of pressure within the product container9 grooves 12 serve to vent the displaced air past the interference wall 13 and past the clearance between product container wall 45 and cylindrical wall 22 and to the atmosphere 0 When the propellant cartridge is lowered to a position near its final seat with bead 21 in contact with shoulder 11, and engaging in an interference fit with wall 139 the bead 21 serves to block the passages provided by grooves 120 Thus;, the last fraction of an inch of travel of bead 21 past wall 45 occurs with the grooves 12 sealed from the atmosphere 0 No significant pressure build-up is experienced since the distance of travel under sealed conditions is so small,, By providing bead 21 at a position near the upper extrem-ity of the propellant chamber wall, nearly all of the displaced air is vented through grooves 12 before sealing is effected. When the cartridge 20 is seated, bead 21 is positioned so as to seal grooves 12 to prevent product leakage o Additionally, the edge of rolled seam 24 is seated on the second annular shoulder 15 to provide a further seal against leakage 0