Aerosol Dispenser For Fluid Products Comprising A Piston Pump Assembly For Generating Compressed Air Serving As Propellant And A Product Metering Device

Abstract

An aerosol dispenser for fluid products which comprises a container, A piston pump assembly mounted therein for generating compressed air propellant, A spray nozzle fixedly mounted in the piston, A compressed air flow path extending from the piston pump to the spray nozzle, A compressed air flow controlling valve in the flow path, A product flow path extending through the piston separate from the air flow path with a product flow control and a product metering device mounted therein; And a connection extending from the valve through the air flow path and engaging the product flow control, thereby opening the product flow path in conjunction with the flow of compressed air.

Description

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 a product metering device.

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. 3,369,757 granted in Feb. 1968 to M. Boris, which dispensers comprise a container for product to be dispensed, a piston pump separately from the product container and having a piston and a cylinder, for generating compressed air as a propellant, a spray nozzle in which compressed air flowing therethrough aspirates, and from which it sprays in aerosol form, 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 Patent No. 768,039, granted on Dec. 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 positive 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 these known dispensers, the product container means is directly connected to the spray nozzle and is normally above the spray nozzle during actuation of the dispenser. Thus, the whole body of product is subjected to aspiration during each operation of the dispenser. To keep the dispenser a convenient size, the product container is made relatively small.

This is also the case in another type of the applicant's aerosol dispensers for fluid products which comprises 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 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 said spray nozzle; and wherein the said product container and product flow control means are mounted on the said mounting and the said mounting is detachably connected to the piston of the said piston pump, forming a mounting-piston assembly; and wherein the said piston is hollow and constitutes the housing for the remaining parts of the said compressed air-controlling valve means being mounted in the piston.

The applicants have also found that, with this last-mentioned and similar dispensers developed by them, it may in some cases be difficult to time the outflow of product from the product container to the spray nozzle so that such outflow ceases exactly with, or shortly before, the ending of the flow of compressed air through the spray nozzle, when the opening of the product flow-controlling means is effected by direct, positive engagement of the latter with the aid of engaging means provided on the compressed air flow-controlling valve member.

It is, therefore, a first object of the instant invention to provide an aerosol dispenser of the last-mentioned type, in which the amount of product available for each dispensing operation is so limited that it will cease before the flow of compressed air from the piston pump through the spray nozzle ceases entirely, when the said control valve is opened by direct mechanical contact as described above.

It is another object of the present invention to provide an improved fluid product aerosol dispenser of the type described above which has a larger product container means in a part of the dispenser where it does not unduly increase the bulk of the latter or make it awkward to handle, and a product metering device between the product container means and the product-aspirating spray nozzle.

Yet another object of the invention is to provide a fluid product aerosol dispenser of the type described in which the metering device and the product container means are arranged so that by inverting the dispenser and then righting it, only a small amount of product is placed in position to be dispensed.

These objects are achieved by the provision of an aerosol dispenser for fluid products, comprising container means for product to be dispensed;

a piston pump separately from the product container and having a piston and a cylinder;

a spray nozzle in which compressed air flowing therethrough aspirates, and from which it sprays, product in aerosol form;

duct means for compressed air flow, extending from said piston pump to said spray nozzle;

compressed air flow-controlling valve means in said flowpath and comprising a valve member movable in valve housing and obturating the compressed air flow-path when closed;

a product flowpath separate from said compressed air flowpath, and product flow control means in said product flowpath,

and engaging means provided on at least one of the said valve member and the said cylinder for direct mechanical engagement of the said valve member and cylinder with one another, as the piston approaches or reaches the end position of its compression stroke in the cylinder, for moving at least the said valve member to open the compressed air flowpath; the said engaging means also comprising means for direct mechanical engagement of the product flow control means for opening the latter at the same time as, or a brief instant prior to, the opening of the compressed air flowpath; at least the front end part of said piston extending into said cylinder constitutes the said valve housing of the compressed air flow-controlling valve means, the said spray nozzle being fixedly mounted in said piston, the said duct for compressed air flow extending through the piston, a product metering device being mounted on the said piston adjacent said spray nozzle in said product flowpath, and said product flow control means being located between said metering device and said spray nozzle, the said product container means comprising a product reservoir surrounding the cylinder of said piston pump and the said product flow-path extending from said reservoir to said metering device through a part of said piston, sealingly separated from the air compression space in said cylinder.

In preferred embodiments of the aerosol dispenser according to the invention, one or several of the following advantageous features can be present:

1. Spring means in the cylinder can engage the front end of the piston facing into the cylinder and urging the piston out of the cylinder.

2. One-way valve means for admitting air into the cylinder during the return stroke of the piston can be mounted in the wall of the cylinder.

3. The engaging means can comprise an abutting part on the inside of the bottom end wall of the cylinder of the piston pump, and a projection of the valve member extending out of the front face of said piston facing toward the cylinder bottom end wall when out of contact with the abutting part.

4. The compressed air flow-controlling valve means can comprise spring means and a valve seat in the valve housing, which spring means urge the valve member against the valve seat.

5. A valve body of the product flow control means can be biassed toward closed position and comprise abutting means in an open end of the compressed air flow duct of the piston and the valve body of the compressed air flow-controlling valve means can bear contact rod means extending through the said duct and engage the abutting means of the product flow control means and thereby open the product flowpath, when the abutment means in the piston pump act on the valve member of the compressed air flow-controlling valve means.

6. The product flow control means can comprise valve seat means engaged by the product valve body when in closed position and elastically deformable membrane means engaging the product valve body and biassing the latter into engagement with the valve seat means.

Structural and operational features of a similar aerosol dispenser and of a preferred embodiment of the dispenser according to the invention are shown in detail in the accompanying drawings and will be readly understood therefrom taken alone or together with the description thereof following hereinafter.

In these drawings:

FIG. 1 is an axial sectional view of a similar aerosol dispenser (lacking means for actuating mechanically the product flow control means) with the parts in the non-dispensing positions;

FIG. 2 is an axial sectional view of the upper part of the dispenser shown in FIG. 1 with the parts in the dispensing positions;

FIG. 3 is an enlarged cross-sectional view of the embodiment shown in FIG. 1 taken along the line III -- III therein;

FIG. 4 is an axial sectional view of the upper part of a preferred embodiment of an aerosol dispenser according to the invention with the parts in non-dispensing positions, and having improved product flow control means; and

FIG. 5 is an axial sectional view of the embodiment shown in FIG. 4, but with the parts in dispensing positions.

In these figures, like parts are designated by like numerals. The earlier dispenser shown in FIGS. 1 to 3 comprises a piston pump consisting of the cylinder 1, the piston 2, a return spring 3 urging the piston 2 and the cylinder 1 away from each other, an outer product container mantle 4, a compressed air flow-controlling valve assembly generally indicated by numeral 5, a spray nozzle 6 housed in the piston 2, and a product metering device 7 and product flow control means, generally indicated by numeral 8, mounted on the outer end of the piston 2, opposite the end thereof facing into the interior of the cylinder 1.

More in detail as seen in FIGS. 1 and 2, the valve assembly 5 has a valve housing part 10 constituted by a part, of reduced cross sectional diameter, of piston 2 extending into cylinder 1. A longitudinally extending passage or duct 14 in piston 2 opens at one end into an enlarged recess 13, which in turn opens in the bottom of the valve housing 10. The duct 14 opens at its other end into a chamber 38a being a reduced diameter portion of a recess 38 in the sidewall of piston 2.

Aspirating spray nozzle 6 is formed as a Venturi nozzle insert 39 and is positioned in the recess 38, leaving an annular product supply chamber 37 around the nozzle insert. Radial product ducts 37a lead from the supply chamber 37 to the Venturi neck portion 39a in nozzle insert 39, which connects the convergent chamber 39b, into which compressed air is introduced via chamber 38a, with the divergent discharge chamber 39c from which the product in aerosol form is sprayed out of the dispenser. The passage 14 forms a compressed air flow path through the valve housing part 10 to the nozzle insert 39.

Against the bottom end portion 10a of the valve housing part 10 over the recess 13 therein, there is fastened an apertured, elastic valve seat disk 34 held in place by the retaining ring 35 which is mounted by means of a threading 35a on the reduced diameter end portion 10a of valve housing part 10. Within the recess 13 and in engagement with the valve seat disk 34, there is provided a poppet valve member 15 which is urged toward the valve seat disk 34 by a return spring 23 positioned in the recess 13.

The cylinder 1 is fitted over valve housing part 10 of piston 2, and extends part of the way along the same. A transverse wall 11 in the cylinder 1 has an inwardly extending poppet valve-actuating pin 18 thereon aligned with the central aperture in the valve seat disk 34. Piston return spring 3 is held between a supporting ring 12 about the pin 18 on the one hand and the retaining ring 35 of valve seat disk 34 on the other hand.

The transverse wall 11 of cylinder 1 has apertures 33 therethrough opening into the interior of the compression chamber 17 therein. An annular flexible gasket 36 which fits over pin 18, overlies the apertures 33, preferably closing each aperture by means of a peripherally loose flap portion 36a thereof, while its central portion 36b is held in place about pin 18 on transverse wall 11 by means of supporting ring 12.

The assembly of gasket 36 and supporting ring 12 constitutes an air return means for admitting air into compression space 17 in cylinder 1, between transverse wall 11, and the front end of piston 2.

A first piston sealing ring 20 is positioned between the inside cylindrical surface of the cylinder 1 and the outer cylindrical surface of the valve housing part 10 of piston 2, preferably by being inserted in an annular groove 35b of retaining ring 35. This O-ring 20 prevents escape of compressed air from compression space 17. A hollow sleeve-shaped extension 9 extends downwardly from the transverse wall 11 of the cylinder 1 and has an open bottom end 9a.

A second piston sealing ring 21 is provided between a hollow collar part 22 of cylinder 1, being of wider diameter than part 10, and the outside wall of the upper part of piston 2. Sealing ring 21 is preferably an O-ring placed about piston 2 in an annular groove 2a of the latter. Cap screw 19 screwed on to the top end of cylinder 1 by means of threading 19a prevents complete separation of cylinder 1 and piston 2 due to its central opening 19b being slightly narrower than the outer diameter of sealing ring 21.

A product container 16 is formed by product container mantle 4 surrounding the cylinder 1 and the extension 9 thereof. The upper end of the product container mantle 4 is threaded at 4a, and is threadedly joined to the collar part 22 of cylinder 1, which surrounds the valve housing part 10 of piston 2 and which has large vents or ports 22a in its sidewall for the passage of product from the product container 16. Ports 22a extend downwardly in the wall of collar part 22 to where the latter part joins the top end of cylinder 1 proper. Through these vents 22a the interior 22b of collar part 22 around valve housing part 10 is in communication with the interior of the product container 16.

The annular bottom wall 4b of the product container mantle 4 extends over the open end 9a of cylinder extension 9 and is sealed thereto by a ring gasket 25, and an aperture 26 is provided in the bottom wall 4b of the container mantle 4, opening into the hollow interior of the cylinder extension 9.

Extending axially through the piston 2 is a product channel 27 of crescent-shaped cross sectional area which has its inner end opening out of the upper sidewall of valve housing part 10 in to the surrounding interior 22b of collar part 22.

The sidewall of a metering cup 28 is inserted in a recess 28a which is provided in the top end of piston 2, which projects to above the product container 16 and beyond the nozzle insert 39. The metering cup 28 is closed at the top by a closure means, here shown as a cap 29 which is screwed on to the top end of piston 2 by means of a threading 29a. In the sidewall of metering cup 28, windows 28b are provided through which the outer end of the product channel 27 is in communication via cap recess 30 with the interior of metering cup 28, the bottom 28c of the recess 28a is concave, and out of the bottom opens a product duct 31 which extends through the top part of piston 2 into the product-supply chamber 37. A product flow control means 8 is provided at the bottom of metering cup 28 in recess 28a, which control means 8 is here shown in the form of a diaphragm 32, having a slit 32a therein.

The size and shape of the product container 16 is sufficiently large to hold a relatively large quantity of product, enough for the dispenser to be operated a great number of times while dispensing only a small amount of product each time. The size of the metering cup 28, on the other hand, is relatively small, containing only a small amount of product, which may be several times but is preferably slightly less than, the quantity which could be dispensed by the amount of compressed air available for each operation of the dispenser. The total volume of the metering cup 28, cap interior 29b and channel 27 is such that even the maximum amount of air flowing through the nozzle insert 29 cannot aspirate product from the product container 16 thereinto. In this way, the compressed air passing through the nozzle insert 39 aspirates product only from the amount of product contained in the metering cup 28. This makes the device more efficient and accurate, since energy is not used to draw product all the way to the nozzle insert from the container 16. The metering chamber 28 is filled after every few operations or preferably after every operation, of the dispenser in a manner described hereinafter.

In operation the parts of the dispenser are normally in the positions as shown in FIG. 1. The spring 3 holds the cylinder 1 and the piston 2 spaced apart, and the air passage through the air return means in the transverse wall 11 of cylinder 1 is free to open. It will be assumed that the metering cup 28 is filled with product. Pressure is the exerted on the bottom wall 4b of the product container 16 and cylinder extension 9, and at the same time on the cap 29, for example, by the thumb and forefinger of the hand, to urge the cylinder 1 and the piston 2 toward each other while compressing the spring 3. The air compressed within the compression chamber 17 of cylinder 1 presses the flaps 36a of air return gasket 36 over apertures 33 and prevents flow of air therethrough. The poppet valve member 15 is held seated by the spring 23 and the sealing ring 20 prevents escape of compressed air from the compression chamber 17 past the gap between cylinder 1 and the valve housing portion 10 of piston 2. When the parts reach the positions shown in FIG. 2, the actuating pin 18 on the inside of the transverse wall 11 of the cylinder 1 engages the poppet valve member 15 and lifts it from its seat 34. Compressed air then escapes through the compressed air flow path formed by the recess 13 and passage 14 and through the nozzle insert 39. The flow of compressed air through the nozzle insert creates a reduced pressure through the duct 31 and in the concave portion 28c of the recess 28a, thus causing the diaphragm 32 to bend downwardly to open the slit 32a. Only the product in the metering cup 28 is aspirated through the duct 31, and is entrained in the flow of compressed air and dispensed as a spray from the nozzle insert 39. No product is aspirated from the product container 16.

Release of the pressure on the parts of the dispenser enables the spring 3 to urge the cylinder 1 and the piston 2 apart. The spring 23 immediately seats the poppet valve member 15. The air return valve means relieves the vacuum within the compression chamber 17 of cylinder 1, and the parts return to the positions of FIG. 1. This operation preferably empties the metering cup 28. Then the device is inverted and product flows through product channel 27 into the metering cup 28 to refill it. The device is then ready for the next operation.

The arrangement of the collar part 22 around the valve housing part 10 of the piston 2 and its connection to the cylinder 1 of which it forms an extension makes possible the admission of air to the product container to break any vacuum which may be formed therein during aspiration of product. As the cylinder 1 moves toward the piston 2 along the reduced diameter valve housing part 10, the collar part 22 moves along the outside of the valve housing part 10. When the zone of the collar part 22 containing the ports or vents 22a therein moves past the sealing ring 21, the vents 22a will be open to the atmosphere through the space between the collar part 22 and the outside of the piston 2. This will take place each time the piston 2 is actuated to cause aspiration of product. Ths aspiration will thus never have to take place against a vacuum. This also enables the product to flow easily from the product container 16 through the product flow path formed by the space 22b around the reduced diameter valve housing part 10 and the channel 27 to the metering cup 28 when the dispenser is inverted. The diaphragm 32 must be sufficiently rigid to prevent product from flowing through its slit 32a when the dispenser is in the inverted position.

As the valve housing 10 forms part of the piston 2 within the cylinder 1, this eliminates the need for a separately formed piston as has been required in prior art dispensers. All parts of the dispenser thus are relatively easily molded sleeves and body parts.

Moreover, by providing the metering cup 28 between the product container 16 and the aspirating nozzle 39 the operation of the aspirating nozzle 39 has been improved because it acts on only a relatively small body of fluid. Nevertheless, the product container 16 can hold a sufficient amount of product to give the dispenser a long, useful life.

In the embodiment of an aerosol dispenser according to the invention shown in FIGS. 4 and 5, the metering device 7 is provided with a product outlet control means which comprise, in lieu of the slit diaphragm 32, an accordion-type flexible, elastic unperforated membrane 40 which engages in its central fold the stem end 41a of a valve disk 41. Valve disk 41 is seated, when in closed position, on a cylindrical upper wall portion 42 which can be integral with accordion-type membrane 40 and is held in place in piston top recess 28a by means of the cylindrical wall of metering cup 28. Wall portion 42 has an orifice 42a therein through which the interior of the metering space within the accordion-type membrane 40 below the valve disk 41 communicates with the annular product supply chamber 37 of the spray nozzle 39 via a duct 43 in the top portion of the piston 2. Poppet valve member 15 of the compressed air flow-controlling valve means 5 has an elongated rod 44 on the side thereof toward the metering device 7. This rod 44 extends into the duct 14 and bears longitudinal grooves 44a so as to allow unimpeded flow of compressed air through the latter duct toward nozzle insert 39.

The tip 44b of rod 44 may be in direct contact with the underside of accordion-type membrane 40 at all times, which would mean instantaneous opening of the product flow controlling means when actuating pin 18 engages and raises poppet valve member 15. It is, however, preferred to locate the tip 44b of rod 44 a small distance beneath the underside of accordion-type membrane 40, whereby the product outlet control means open a short time, e.g., a fraction of a second, after the poppet valve member 15 is raised from its seat disk 34, so that the product flowing through duct 43 will be entrained into the full stream of compressed air through Venturi neck portion 39a. If product were to flow through duct 43 too early there would be the danger of having a larger product droplet present in neck portion 39a which would lead to an initial spray of higher product content than in the subsequently developed aerosol cloud.

It is a particular advantage of the dispenser according to the invention that there is no excess product flowing into the spray nozzle and remaining therein after spraying, which could lead to decomposition and clogging of the nozzle. If the volume of the metering cup 28 and that of the compression chamber 17 are so proportioned that there is still compressed air passing through Venturi neck portion 39a when product from the metering cup 28 has already been exhausted, the final stream of compressed air cleans the nozzle from residual product and guarantees a longer life of the nozzle.

As a further advantage of the embodiment shown in FIGS. 4 and 5, the valve housing part 10 is detachably connected by means of a threading 10b to the upper portion 2b of piston 2. It is thus easy to remove the valve housing part 10 as well as the cap 29 and metering device 7 from piston upper portion 2b and replace the latter including the spray nozzle housed therein by a new piston and nozzle insert, while preserving the more expensive parts containing valves, springs, etc.

Claims

I claim:

1. An aerosol dispenser for fluid products, comprising container means for product to be dispensed,

a piston pump separately from the product container and having a piston and a cylinder and an air compression space therein,

a spray nozzle in which compressed air flowing therethrough aspirates, and from which it sprays, product in aerosol form,

duct means for compressed air flow, extending as a flowpath from said piston pump to said spray nozzle,

compressed air flow-controlling valve means in said flowpath and comprising a valve member movable in a valve housing and obturating the compressed air flowpath when closed,

a product flowpath separate from said compressed air flowpath,

product flow control means in said product flowpath,

engaging means provided between said compressed air flow-controlling valve means and said cylinder, which engaging means comprises an abutting part on the inside of the end wall of the compression space in said cylinder and a projection of said valve member extending out of the front face of said piston facing toward said compression space end wall when out of contact with said abutting part, and

a product metering device mounted on the said piston adjacent said spray nozzle in said product flowpath;

said product flow control means comprising a valve member biassed toward closed position and being

provided with abutting means in an open end of said compressed air flow duct in said piston, said valve member comprising contact rod means extending through said air flow duct and engaging said abutting means of said product flow control means and thereby opening the product flowpath, when said abutment means in the piston pump act on the valve body of said compressed air flow-controlling valve means;

wherein at least the front end part of said piston extending into said cylinder constitutes the said valve housing of the compressed air flow-controlling valve means, said spray nozzle is fixedly mounted in said piston, and said duct means for compressed air flow extends through the piston,

said product flow control means are located between said metering device and said spray nozzle, said product container means comprises a product reservoir surrounding the cylinder of said piston pump and the said product flowpath extends from said reservoir to said metering device through a part of said piston sealingly separated from the air compression space in said cylinder.

2. An aerosol dispenser as described in claim 1, in which said metering chamber is disposed on one side of said spray nozzle in the direction of the relative movement of said cylinder about said piston, and said product reservoir is disposed on the opposite side of said spray nozzle, whereby product can be caused to flow from the product container to the metering chamber by inverting the dispenser.

3. An aerosol dispenser as described in claim 1 in which said product reservoir is provided around said valve housing part of said piston and is connected to said cylinder for movement therewith, said product reservoir bring in free communication with part of the interior of said cylinder separated sealing by from the compression space of the latter, and being in sliding and sealing engagement with said piston.

4. An aerosol dispenser as described in claim 3 in which air return means is provided between said product reservoir and said valve housing part of said piston for admitting air to said product reservoir at the end of each compression stroke of said piston.

5. An aerosol dispenser as described in claim 4 in which said product reservoir has a collar part at the top thereof around said valve housing part of said piston and, a sealing ring in sliding sealing engagement between said collar part and said valve housing part, said product flowpath through said piston opening out of said valve housing part within said cylinder interior part in communication with said reservoir.

6. An aerosol dispenser as described in claim 5 in which said collar part has a hollow interior about said valve housing part of said piston, and at least one vent is provided in the wall of said collar part through which vent said product flow path opens into said reservoir, said collar part moving relative to said sealing ring on said valve housing part during a compression stroke, whereby said vent extends past said sealing ring at the end of said compression stroke to place the interior of said reservoir in communication with the outside atmosphere.

7. An aerosol dispenser as described in claim 1, wherein said compressed air flow-controlling valve means comprise spring means and a valve seat in said valve housing, said spring means urging said valve member against said valve seat.

8. An aerosol dispenser as described in claim 1, wherein one way valve means for admitting air into said cylinder compression space during the return stroke of said piston are mounted in the wall of said cylinder.

9. An aerosol dispenser as described in claim 1, wherein said product flow control means comprise valve seat means engaged by said product valve member when in closed position and elastically deformable membrane means engaging said product valve member and biassing the latter into engagement with said valve seat means.