Abstract:
An aerosol dispenser for fluid products is described which has a container for product to be dispensed, a separator piston pump for generating compressed air as a propellant, a spray nozzle for aspirating, and spraying product from the product container, flowpaths, for compressed air from the piston pump, and for product from the product container, to the spray nozzle, valves and associated with the flowpaths and opening the paths dependent on the piston approaching or reaching full compression stroke position in the cylinder of the aforesaid piston pump. An abutment in the piston pump acts, in the aforesaid compression stroke position, on the valve body of the compressed air flow-controlling valve. The product flow control valve has a flexible elastic diaphragm across the compressed air flowpath and separating the latter from the interior of the product container. A product outlet in the wall of the product container outside the flexible elastic diaphragm is part of the flowpath for product to the spray nozzle, and a movable valve member is mounted in the flexible elastic diaphragm, the flexible elastic diaphragm being biassed to hold the movable valve member to close sealingly the product outlet when the piston pump is in other than the full compression stroke position.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to aerosol dispensers for fluid products, comprising a piston pump assembly for generating in the interior of the dispenser compressed air serving as propellant, and improved product flow control means. Various types of aerosol dispensers utilizing compressed air for dispensing fluids in the form of a spray are known. Among them are especially aerosol dispensers for liquid products described in U.S. Pat. No. 3,369,757 granted on Feb. 20, 1968 to M. Boris, which dispensers comprise a container for product to be dispensed, a piston pump separately from the product container, for generating compressed air as a propellant, a spray nozzle in which compressed air flowing therethrough aspirates, and sprays, product from the product container, flowpaths for compressed air and product to the spray nozzle from, respectively, the piston pump and the product container, and obturating means associated with the said flowpaths and opening these paths in dependence on a determined compression position of the piston in the cylinder of the aforesaid piston pump. 
     These known dispensers suffer from the drawback that the timely opening of the obturating means for the compressed-air flow which comprise a spring-biassed ball valve, is effected by the pressure of the compressed air alone, and hence not reliable as it depends on the quality and age of the spring material, and the valve must open before a valve shaft controlling the product flowpath can open. This leads unavoidably to a loss of compression. 
     In order to overcome this drawback, there is described in Belgian Pat. No. 768,039, granted on December 3, 1971 to the Applicant, an improved type of the above-described aerosol dispensers, wherein at least the valve controlling the flow of compressed air is opened by the mechanical action of rigid force-transmitting means comprising abutment means on the piston of the piston pump and on a displaceable valve disk or stem or the like valve body pertaining to the compressed air flow-controlling valve, which abutment means on the piston and valve body act one upon the other by direct contact or on lever means acting on the aforesaid valve body. 
     In a further development of this improved type of aerosol dispenser, the product container is replaceably mounted on top of a valve housing for the obturating means for the control of both flowpaths mentioned above, and which valve housing has a dependent sleeve forming the cylinder of the aforesaid piston pump, while the piston bears a mantle-type sleeve portion surrounding the cylinder-and-valve housing assembly as an outer guiding and protecting means. 
     However, with certain fluid products to be dispensed it may easily occur that deposits of aged or decomposed residual product are formed in the product flowpath leading through the valve housing to the spray nozzle, and especially in the later. 
     When this happens the entire dispenser has to be thrown away. 
     As the springs, which are usually made of steel, and the piston pump assembly constitute the more expensive part of such dispensers, U.S. Pat. No. 3,764.046 describes an aerosol-dispenser of the above-described type, wherein the product container and the spray nozzle insert are part of a replaceable unit, while the piston pump assembly including a compressed air flow-controlling valve means and springs is retained by the user, so that the above unit, which can be mass-produced and is hence inexpensive, is replaced each time a full product container is substituted for an empty container. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide, in an aerosol dispenser of the last-described type, an improved product flow control means for controlling flow of product from the product container to the spray nozzle. 
     Another important object of the invention is to provide an aerosol dispenser of the last described type, the product flow control means are opened by direct mechanical contact with abutment means provided in the piston pump assembly. 
     Yet another object of the invention is to provide an aerosol-dispenser of the last-described type having improved air return means for the cylinder, after compression of air therein. 
     These objects are attained in accordance with the invention by an aerosol dispenser for fluid products comprising a container for product to be dispensed, a piston pump separate from the product container, for generating compressed air as a propellant, a spray nozzle in which compressed air flowing therethrough aspirates, and from which it sprays, product from the product container, flowpaths, for compressed air from the piston pump, and for product from the product container, to the spray nozzle, valve means comprising valve housings and displaceable valve bodies in the housings, and being associated with the said flowpaths and opening the paths dependent on the piston approaching or reaching full compression stroke position in the cylinder of the aforesaid piston pump, abutment means in the piston pump acting, in the aforesaid compression stroke position, by direct mechanical contact on at least the valve body of the compressed air flow-controlling valve means; and a mounting for the spray nozzle, which mounting has a passageway therein being part of the said compressed air-flowpath; 
     wherein the said product container and product flow control means are mounted on the mounting, and the mounting is detachably connected to the piston of the piston pump, forming an assembly with the piston; and wherein the piston is hollow and constitutes the housing for the remaining parts of the compressed air controlling valve means being mounted in the piston; 
     and which is improved by providing therein product flow control means which comprise 
     flexible elastic wall means across the compressed air flowpath and separating the latter from the inerior of the product container; 
     product outlet means in the wall of the product container outside the said flexible elastic wall means and being part of the flowpath for product to the spray nozzle; and 
     a movable valve member mounted in the flexible elastic wall means which latter wall means are biassed to hold the movable valve member to close sealingly the product outlet means when the piston pump is in other than the full compression stroke position. Ducts in the piston and the mounting provide the compressed air flowpath to the spray nozzle. 
     In a first embodiment of the dispenser according to the invention, the bias of the flexible elastic wall means is such as to yield to a pressure increase in the compressed-air flowpath which increase occurs when the abutment means contact and thereby move the valve body of the compressed air-flow controlling valve. The bias should preferably be such that the flexible wall yields to essentially the entire or at least a major portion of the compressed air escaping from the piston pump through the compressed-air flowpath. 
     In contrast to the slitted flexible product valve disc provided in the dispenser described in U.S. Pat. No. 3,764,046 , supra, which is opened due to reduced pressure in the product flowpath to the spray nozzle, causing a suction on the flexible disc which opens the slit therein the re-closing of which when suction ceases is not always absolutely safe, the improved product valve means of the above-described first embodiment closes due to the biassed flexible wall mentioned above pulling a flat head portion which is provided on the movable valve body mounted in the flexible wall portion of the product container against a corresponding seat provided in the adjacent rigid wall of the product container surrounding the said flexible elastic wall portion, thereby hermetically sealing the product outlet communicating with the portion of the product flowpath provided in the mounting and leading to the spray nozzle in the latter, at all times when the pressure of the air present in the compressed air-flowpath is the same as that of the surrounding atmosphere. The product valve thus opens only when and while the air pressure in the compressed-air flowpath is above a certain limit value which is determined by the bias of the flexible elastic wall portion. 
     In another, preferred embodiment of the aerosol dispenser according to the invention, the movable valve member of the product flow control means is biassed toward closed position and comprises abutting means in an open end of the said passageway in the mounting and the valve body of the compressed air flow-controlling valve means bears contact rod means extending through the said passageway and engaging the abutting means of the product flow control means and thereby opening the product flowpath, when the said abutment means in the piston pump act on the valve body of the compressed air flow-controlling valve means. 
     Particularly preferred are also aerosol dispensers according to the invention, in which the product flow control means comprise elastic gasket means biassing the valve body of the control means toward closed position, the said valve body having a hollow portion and a duct for product therethrough and an annular beveled face engaged by the gasket means, and the valve housing of the product flow control means comprises an elastically expandable membrane against one face of which the said hollow valve housing portion abuts when the valve body is in closed position, and the opposite face of which is engaged by the contact rod means mentioned hereinbefore, when the abutment means in the piston pump act on the valve body of the compressed air flow-controlling valve means. In another embodiment, the product flow control means can comprise valve seat means engaged by the valve body of the said product flow control means when in the closed position, and elastically deformable membrane means engaging the abutting means of the last-mentioned valve body and biassing the latter into engagement with the valve seat means. 
     Structural and operational features of preferred embodiments of dispensers according to the invention are shown in detail in the accompanying drawings and will be readily understood therefrom taken alone or together with the description thereof following hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 represents an exploded front view, partly sectioned, of the two basic parts making up the structure of the dispenser according to the invention; 
     FIGS. 2 and 3 are sectional views of another embodiment of the dispenser, FIG. 2 showing the parts in the dispensing position, and FIG. 3 an intermediate position of the parts after dispensing and before the parts have fully reached the non-dispensing or rest position; 
     FIG. 4 represents a front view of the lower part of the dispenser shown in FIGS. 2 and 3, but turned about an angle of 90°; 
     FIGS. 5, 6 and 7 show yet another embodiment of the dispenser, including a preferred type of product flow control means, FIG. 5 showing the parts in the dispensing position; 
     FIG. 6 is a sectional view of the same embodiment as shown in FIG. 5, taken along the line VI--VI therein; and 
     FIG. 8 shows the same embodiment as FIGS. 5 and 6, but with the parts in the non-operative or rest position; and 
     FIGS. 8 and 9 show, in partial sectional views, further embodiments of the product flow control means in a dispenser as shown in FIGS. 5 to 7. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     As shown in FIGS. 1, 2 and 3, the dispenser consists of two units which are detachably connected with each other. The upper unit 1 comprises the product container 2 having a knurled outside surface 2a, which can be integral with a mounting 3, in a recess of which there is located a spray nozzle insert 5 the discharge orifice 6 of which opens in the lateral wall of mounting 3. The latter bears on its end face 3b away from the product container 2 an annular projection or dependent sleeve 8 which is provided on its annular outer surface with a threads 8a. 
     The spray nozzle insert 5 preferably contains a Venturi nozzle as shown in FIGS. 2 and 3, having a chamber 5a of convergent cross section, a narrowest passage or neck duct 5b and a chamber 5c of divergent cross section opening through discharge orifice 6 to the outside. An axial duct 9 leads from the bottom face 3b through mounting 3 to the convergent chamber 5a. A passageway 10 connects the hollow interior of product container 2 via an annular recess 10a and a plurality of radical passages 5d with neck duct 5b of the Venturi nozzle 5. 
     The lower dispenser unit 15 comprises an outer mantle or cylinder 16 the lower bottom end portion 17 of which constitutes the cylinder of a piston pump assembly for the generation of compressed air when using the dispenser. The mantle 16 has an opening 16a which, in the dispensing position, registers with discharge orifice 6 of spray nozzle insert 5, while it covers that orifice in the non-dispensing position. 
     The hollow piston 18 of the piston pump assembly constitutes a valve housing being part of the compressed air flow-controlling valve means, and houses an obturating gasket 19 having a central orifice 19a through which a poppet valve body 20, having a stem part 20a and a disk-shaped flange 20b, extends with its lower stem portion 20c forming a poppet valve-actuating pin into, and in the rest position out of, a recess 18a in the front end wall 18b of piston 18. Obturating gasket 19 is held in place in the bottom of the hollow interior of piston 18 by means of a cylindrical retaining member 21. Piston 18 bears on the inside wall of its outer rear end away from the front end 18b inner threads 18c by means of which it is screwed on to the threads 8a of mounting 3. Thereby, retaining member 21 is held in place by being squeezed between the gasket 19 and a sealing ring 22 inserted in an annular groove 23 in the outer end face 21a of member 21. 
     From an inner recess 24 of retaining member 21, about valve body 20, an axial duct 25 of reduced cross sectional area leads to the rear end face 21a of member 21 and opens in the latter to register with duct 9 in mounting 3, thus being part of a flowpath for compressed air leading from the interior of cylinder 17 via piston recess 18a and orifice 19a in gasket 19 through recess 24 and ducts 25 and 9 to convergent chamber 5a of spray nozzle 5. 
     In the recess 24 of retaining member 21, there is housed a return spring 26 one end of which is supported on the disk-shaped flange 20b of poppet valve body 20, and the other on the end wall 24a of recess 24, thus urging the valve body 20 into a closed position against gasket 19. 
     The interior 17a of cylinder 17 is sealed off against the surrounding atmosphere by means of a sealing ring 27 held in a circumferential groove 27a about piston 18 and sealingly and slidingly engaging the inner wall of cylinder 17. Moreover, vent holes 28 in the bottom end wall 17b of cylinder 17 are closed off, during compression, by means of the flexible elastic portion of a flap valve 29 which is held in position across the vent holes 28 on the inside of cylinder bottom wall 17b by means of a retaining ring 30 held in place about an inwardly projecting frustoconical centering and abutting member 31 by means of return spring 32 which is located in the cylinder interior 17a and has its one end supported on an annular shoulder 30a of retaining ring 30 and its other end against an annular shoulder 18d about piston 18 a short distance away from piston front wall 18b. A guiding peg 7 projects from the outer wall of piston-valve housing 18 near the end thereof joined to mounting 3 and engages a longitudinal groove 33a in the inside wall of mantle 16 into which it is inserted through a bayonet slot 33 (FIG. 4). 
     In the embodiment of FIGS. 2 and 3, product is held in a flexible collapsible or compressible bag which is in turn housed in a product container. 
     In a recess 10b of mounting 3 there is inserted a valve gasket 35 having a flat annular gasket portion 35a, and a cup portion 35b the vaulted bottom wall 35c of which is very flexible and elastic and has a central opening 35d in which there is sealingly inserted and firmly held the stem portion 36a of a poppet valve member 36, the disk-shaped head portion 36b of which rests with its periphery on the flat gasket portion 35a, preferably by means of a sealing ring 37 fixed on the underside of head portion 36b, whereby the interior of a product bag 38, the peripheral rim zone 38a of which about its opening is crimped about the outside rim portion of flat gasket portion 35a is sealed off. Gasket 35 is held about the latter and in position in the recess of projecting socket portion 40 of mounting 3 by means of a cap member 41 which is screwed into place in socket portion 40 by means of a threading 42. Cap member 41 has at least one vent hole 43 therein by way of which the interior of the cap member is always in free communication with the outside air, so that ambient pressure is exercised at all times on the outside of product bag 38. In the wall of cup portion 35b there is a lateral opening 35e through which product can flow from bag 38 to the spray nozzle 5. 
     Poppet valve stem 20a is provided with an extension rod 20d which extends at all times for better guidance into the lowermost end of axial duct 25 retaining member 21. The extension rod 20d is provided with a plurality of longitudinal grooves 20e to provide less restricted passage of compressed air therealong. 
     In operation, the upper unit 1 is pressed into the outer mantle 16, for instance by the user holding the mantle 19 below the nozzle discharge orifice 6 with the thumb and middle finger and exerting pressure on the top product container lid 41 with the index finger. Thereby piston 18 compresses air in the interior 17a of cylinder 17. 
     A pressure builds up in cylinder interior 17a, flap valve 29 is urged against the inner bottom wall 17b of cylinder 17, thus obturating vent holes 28. 
     Toward the end of the compression stroke, poppet valve actuating pin 20c is contacted and raised by abutting member 31, poppet valve disk-flange 20b is lifted from gasket 19 with compression of return spring 26, and compressed air flows through ducts 25 and 9 and through nozzle 5. The compressed air flowing through axial duct 9 of mounting 3 impinges on the flat tip 36c of poppet valve stem portion 36a and raises the poppet valve body 36 from its seat gasket portion 35a, (see FIG. 2), before entering the convergent chamber 5a of nozzle 5, thereby uncovering lateral opening 35e and permitting product to be suctioned via opening 35e and product passageway 10 into annular chamber 10a and into the compressed air stream flowing through Venturi neck 5c. 
     As soon as compressed air is exhausted and pressure on upper unit 1 ceases, valve 11 closes again, product flow ceases, but air from the outside may pass through the slot 11a at the moment of closing from the nozzle 5, and replace product withdrawn from container 2. Return spring 26 causes poppet valve body 20 to close again, and return spring 32 urges cylinder 17 away from piston 18. As this causes a partial vacuum in cylinder interior 17a, flap valve 29 is bent upwardly and outside air fills the cylinder interior 17a. The dispenser is then ready for renewed use. 
     In a preferred embodiment of the invention which is shown in FIGS. 5, 6 and 7, the opening and closing of both the valve means for controlling the compressed air flow and for controlling product flow is effected by direct mechanical action, independently of the degree of vacuum generated at the product flow control means. 
     For this purpose, the latter means comprise a self-closing valve consisting of a valve gasket 35 similar to that used in the embodiment of FIGS. 2 and 3, but having its flexible and elastic bottom wall 35b unperforated. On the flat annular gasket portion there rests an annular flexible elastic gasket 44, which can also be made integral with valve gasket 35. The width of central gasket opening 44a is smaller than that of cup portion 35b, and preferably slightly smaller than the diameter of the narrowest neck portion 45a of a valve stem 45 which has a head portion 45b of greater diameter than neck portion 45a and merging with the latter via an upper beveled annular zone 45c, which head portion protrudes into the interior of product bag 38, while the neck portion 45a merges at its other end with a hollow valve stem plug 45d of greater diameter via a lower beveled annular zone 45e. The annular interior chamber 46 of stem plug 45d is connected through opening 46a in plug wall and opening 35e in a cup portion 35b of valve gasket 35 with product duct 10c and via the latter with spray nozzle 5, and, on the other hand, via a plurality of ducts 46b opening in lower beveled zone 45e of stem 45 with the interior of bag 38, when the central portion of gasket 44 about its central opening 44a is bent inwardly into bag 38 and out of contact with stem neck portion 45a, thus clearing the openings of ducts 46b. 
     This occurs when the extension rod 47 bearing longitudinal grooves 48, which rod is long enough to extend through the entire length of duct 25 and into duct 9 of mounting 3&#39;, contacts the outside of bottom membrane 35f which closes off cup portion 35c of valve gasket 35, and raises the latter membrane and together with valve stem 45 due to the fact that poppet valve body 20 is lifted by coming into contact with abutting member 31. 
     This means that the poppet valve body 20 and valve stem 45 will open the flowpaths for compressed air and for product practically simultaneously, unless the opening of the product flowpath is delayed a very short time, for instance by locating the orifices of axial ducts 46b at a smaller or greater distance from where the lower beveled zone 45e and the neck portion 45a merge. 
     This will have the advantage that product flow is cut off when terminating spraying, before the flow of compressed air ceases completely, thereby preventing or reducing the accumulation of residual product in the product flowpath to nozzle 5. Such accumulated product will often be decomposed and form tacky or resinous residues which will clog the product flowpath and possibly the spray nozzle neck duct 5b. 
     FIGS. 8 and 9 show further embodiments of the product flow control means, combining features of the embodiments thereof shown in FIGS. 2 and 3 on the one hand, and 5 to 7 on the other hand. Thus, the embodiment of FIG. 8 shows a self-closing valve 50 equipped with the same kind of poppet valve body 36 as the product flow control valve in the embodiment of FIGS. 2 and 3. However, the vaulted bottom wall 50c of the cup portion 50b of valve 50 is of accordion shaped and, after pressure on the flat tip 36c of poppet valve member 36 has ceased, which pressure may be mechanically exerted by the top end of extension rod 47, or dynamically by compressed air impinging on tip 36c and the underside of accordion wall 50c, the latter will return to its initial uncompressed condition as shown in FIG. 8 and will pull the disk-shaped head portion 36b with its annular peripheral sealing ring 37 into sealing contact with the valve seat formed by the flat annular gasket portion 50a of valve 50. 
     Accordion wall 50c has a central opening 50d for receiving the valve stem portion 36a therein, and cup portion 50b has a lateral opening 50e for the flow of from the product bag 38 when valve 50 is open. 
     FIG. 9 shows a dispenser similar to that of the preceding embodiment of FIG. 8, but with a somewhat different product flow control valve structure. In most cases, this structure will be preferred because of its simple, rugged nature. 
     The accordion wall 50c of product control valve 50 in the preceding embodiment is replaced by a flexible, compressible, but less elastic bottle neck-shaped membrane 50f which is unperforated and encloses the valve stem tip 36c, the latter being pressed into a recess 50g in the inside wall of membrane 50f. 
     A further simplification resides in the replacement of annular sealing ring 37 by a frustoconically beveled lower rim 37a or disk shaped head portion 36b of poppet valve member 36. In the closed position, this beveled rim 37a is sealingly seated on a correspondingly beveled annular zone 50h about the central opening of flat annular gasket portion 50a of self-closing valve 50. The operation of this embodiment is the same as that of the embodiments shown in FIGS. 5 to 8. 
     With this arrangement, the upper dispenser unit 1 including the product container 2 and the spray nozzle insert 5 are replaceable. All that is necessary is to grasp the knurled exterior surface 2a and unscrew the mounting 3 from the open end of the hollow piston 18. Since this threaded engagement is the only interfitting engagement between the mounting 3 and the remainder of the device, once the threaded engagement is ended, the upper dispenser unit 1 can simply be withdrawn from the remainder of the device. Replacement requires only threading a new upper dispenser unit 1 into place. The advantage of this arrangement is that not only is the supply of the product in the container 2 replaced, but a whole new product dispensing system is provided, i.e. the product flow control means 11, 35 or 50, the passageway 10 or 10c and the spray nozzle insert 5. This avoids malfunctions of the device due to clogged or improperly operating product flow control means and passages, and clogged nozzle inserts. 
     The product flow control means 35 or 50 are a novel feature of the present invention. They comprise a membrane of flexible, elastic material, such as rubber or synthetic resin which is unaffected by the product being dispensed. 
     The air return means in the cylinder bottom is also simple and yet reliable in operation, and consists only of the gasket 29 and the retaining ring 30 and the configuration of the inside of the closed end of the cylinder. 
     Thus, the product container and the spray nozzle insert are part of a replaceable unit, while the piston pump assembly including a compressed air flow-controlling valve means and springs is retained by the user, so that the above unit, which can be mass-produced and is hence inexpensive, can be replaced each time a full product container is substituted for an empty container. 
     It will also be seen that this aerosol dispenser by its very nature dispenses a metered dose of product and the dose can be varied by changing the size of the piston pump. 
     In preferred embodiments of the aerosol dispenser according to the invention, not only the compressed air flow-controlling valve means but also the product flow control means are opened by direct mechanical contact with abutment means provided in the piston pump assembly, when the upper dispenser unit is depressed into the cylinder of the piston pump, and the piston approaches or reaches the full compression stroke position. Especially advantageous features of these preferred dispensers are that product can be aspirated only after compressed air has begun flowing through the spray nozzle, and that the dispensers can be used equally well in upright as in upside-down or in oblique position without having excessive amount of product flow into the spray nozzle under the effect of gravity; thereby the same fineness of spray is preserved regardless of the position of the dispenser, and is determined exclusively by the characteristics of the spray nozzle and of the product being sprayed.