GB1572818A

GB1572818A - Foam device

Info

Publication number: GB1572818A
Application number: GB34874/76A
Authority: GB
Original assignee: AFA CORP
Current assignee: AFA CORP
Priority date: 1976-08-20
Filing date: 1976-08-20
Publication date: 1980-08-06
Also published as: AU2729077A; IT1079826B; DE2737160A1; SE7709265L; BR7705556A; FR2361933B1; AU510972B2; DK370077A; JPS5340404A; CA1074365A; BE857971A; NO772835L; CH613105A5; NL7708634A; FR2361933A1

Description

(54) FOAM DEVICE (71) We, THE AFA CORPORA TION, of 14201 N.W. 60th Avenue, Miami Lakes, Florida 33014, United States of America, a Corporation organised and existing under the laws of the State of Florida, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to a device for use in conjunction with a liquid dispenser, preferably of the trigger type or finger pump type which device causes the product to be dispensed in the form of a foam rather than in the form of a stream spray or mist.

Trigger-type dispensers with which the devices described herein are particularly useful are illustrated by British Patent Specifications Nos. 917,1351,315,866 and 1,331,842 which correspond to U.S Patents 3,061,202; 3,685,739 and 3,650,473 respectively.

Foam-generating nozzle units adapted for use with dispensers of the trigger type are the subject of U.S. Patents 4,013,228 and 3.946,947. While these devices are effective, they are characterized in practice by a high length to diameter ratio which presents problems in terms of filling and packaging products having a rather elongate dispenser.

The invention consists in a foam generating device which comprises a body open at one end to receive liquid pumped from a liquid dispenser and at the other end to dispense foamed product, including within the body: (a) a first chamber into which said liquid is introduced in the form of a spray and said liquid is mixed with air, said first chamber having air vents leading to it, (b) a second chamber adjacent said first chamber through which said aerated liquid passes, the second chamber being of substantially the same or lesser crosssection than said first chamber, (c) a third chamber adjacent to and of larger cross-section than the second chamber and which receives aerated product from said second chamber, (d) screening means covering the downstream end of said third chamber and through which the product in the third chamber is forced, and (e) outlet means for dispensing the foamed product.

The invention also consists in a foam generating device which comprises a body open at one end to receive liquid pumped from a trigger-type dispenser and at the other end to dispense foamed product, including within the body: (a) a first air chamber into which said liquid is introduced in the form of a spray for mixing with air, (b) one or more air passages for introducing air into said first air chamber, (c) a second chamber adjacent said first chamber, through which the aerated liquid passes, the second chamber being of substantially the same cross-section as said first chamber and being provided with means for mixing the foam, (d) a third chamber adjacent to and of larger cross-section than said second chamber and which receives aerated product from said second chamber, (e) screening means covering the downstream end of said third chamber, through which the product of the third chamber is forced, and (f) outlet means for dispensing the foamed product.

In the accompanying drawings: Figure 1 is a longitudinal sectional view of one embodiment of the invention and Figure la is a view of this embodiment as seen from its outlet end, the screens having been omitted.

Figure 2 is a longitudinal sectional view of the preferred embodiment of this invention and Figure 2a is a view of this embodiment as seen from its outlet end, the screen having been removed.

The foam producing devices are, in the embodiment of this invention illustrated by Figures I and la, attached to the nozzle of a trigger-type dispenser. In another embodiment, illustrated by Figures 2 and 2a, the nozzle is eliminated as a separate piece and is formed as an integral part of the foam-producing element.

Referring to Figures 1 and Ia, 101 indicates an outer shell or body of cylindrical form, said body containing two screens 110 secured by two screen holders, 109. Body 101 is adapted to be secured to the nozzle of a trigger-type dispenser, generally indicated by 102, which dispenser delivers its product via orifice 103.

Contained within body 101 is aspirating chamber 104 of generally cylindrical shape which abuts dispenser nozzle 103 and which is provided with aspirating slots 105. Slots 105 cooperate with slots 106 located in the body to introduce air into liquid moving through chamber 104. It should be noted that slot 106 defined by the dotted lines in Figure 1 would not normally appear in a sectional drawing; their presence however, helps to illustrate the communication between inner chamber 104, aspirating slots 105 and the atmosphere. Body 101 is also provided with foam-forming chamber 107 of cylindrical shape, having a diameter less than chamber 104, which chamber 107 abuts an expansion chamber 108. Expansion chamber 108 is located between chamber 107 and screens 110, retained by holders 109. Foam molding chamber 111 follows the screens. The diameter of expansion chamber 108 is substantially larger than that of foam-forming chamber 107, the abutting relation of chambers 107 and 108 being such as to provide, as shown in Figure 1, a nozzle at the inlet to the expansion chamber 108.

Referring to Figures 2 and 2a, 1 indicates an outer shell or body of cylindrical form, which may or may not be tapered in the manner shown. At each end, body 1 defines a generally cylindrical opening, one opening, generally indicated at 2, is adapted for attaching the foam body to a dispenser, thereby eliminating the separate nozzle illustrated by 102 in Figure 1. The other opening defines chamber 8 which molds the foam and directs it to its target. Chamber 8 terminates with screen 7, which is interposed between chamber 8 and expansion chamber 9. This chamber has a larger diameter than foam-forming chamber 6 which it abuts, the abutting relation being such as to provide a nozzle at the inlet to expansion chamber 9, as shown in the drawing. Chamber 6 is generally cylindrical and contains one or more interrupter rings 4 which are constrictions formed in the wall of the chamber and function to agitate and homogenize the foam entering from aspirating chamber 10. Communicating between chamber 6 and orifice 3, chamber 10 is optionally provided with one or more wedge-shaped aspirating slots 5 through which air is drawn into aspirating chamber 10 by the movement of liquid there-through.

Chamber 10 abuts orifice 3 through which liquid is forced by the dispenser.

The foam producing devices of the invention are simple to fabricate and are effective in generating foam. The device illustrated by Figure 1 is fabricated in five parts, body 101, holders 109 and screens 110. The device illustrated by Figure 2 is fabricated in two parts, body 1 and screen 7.

Manufacture of molds for production of body members 1 and 101 is a straightforward proposition and presents no difficulties. Similarly, insertion of holders 109 and screens 110 in the device of Figure 1 and the insertion of screen 7 in a device of Figure 2 are straightforward. Screen 7 is conveniently fastened to body member 1 in any convenient manner and, where the screen and body member 1 are of the same material, such as polypropylene, attachment is readily done by sonic welding.

Turning to the device of Figure 1, foam is dispensed by actuating a convenient dispenser, for example by reciprocating the trigger of a trigger-type dispenser in conventional manner. The product exits the trigger-type dispenser, and enters the foam element via orifice 103 into aerating chamber 104 where the liquid is aerated by air brought in through vents 105. The motion of the liquid creates a venturi, causing preliminary foaming to take place in chamber 104. The foam moves on into foam-forming chamber 107 which has a diameter smaller than that of chamber 104.

Foam forming chamber 107 compresses the foam, providing a finer textured foam and accelerates the movement of the foamed product.

From foam forming chamber 107, the foam moves on through chamber 108 and impinges on screens 110, where the larger area facilitates movement therethrough.

There should be at least one and possibly as many as three screens. The screens facilitate foaming, tending to add air and break up the liquid. At three or more screens the back pressure becomes considerable and it might take an unacceptably high amount of pressure to operate the trigger-type dispenser. Where two screens are used, they should be spaced apart, at least .031 inches (.0787 cm) to facilitate the formation of a fine textured foam. If the screens are too close, they perform like a single screen, while if the screens are too far apart, the flow of foam is slowed and the foam can begin to break down before it has passed through the device.

On passing through the screens, the foam passes through chamber 111 where the foam is finally molded and directed to the target.

The character of the foam produced, that is. wet or dry, is primarily a function of the air to liquid ratio and is generally goverened by liquid coming through orifice 103, the amount of air coming in through vents 105, which in the embodiment of Figure 1 are essential, and the size of aspirating chamber 104. Where the trigger-type dispenser has an adjustable nozzle, the adjustment usually provides a means to vary the angle of the stream of liquid or spray that issues from the orifice 103. This adjustment is a convenient means for governing the type of foam. At one extreme of adjustment of the dispenser nozzle, the liquid leaving orifice 103 spreads or flares to provide a wide angle spray. The ratio of air to liquid in chamber 104 is therefore relatively high and the resulting foam tends to be drier and creamier. Adjustment of the dispenser nozzle to decrease the angle of the spray causes the liquid entering the foam element via orifice 103 to be compressed and the ratio of air to liquid in chamber 104 to be relatively lower; the foam produced then tends to be wetter, having less air entrained therein. The wetter foam can generally be projected further than a dry, creamy foam.

Figure 2 presents the preferred embodiment of this invention. The foam device illustrated by Figure 2 is fabricated in two parts, the body and the screen; its assembly is extremely simple. As previously indicated, this embodiment is intended to replace the adjustable nozzle of a triggertype dispenser and is intended to be fastened to such a dispenser in place of the nozzle. Upon reciprocating the trigger of the trigger-type dispenser, liquid is forced through orifice 3 into aerating chamber 10 where it is initially aerated by air entering through vents 5. The aerated material moves into foam forming chamber 6, passing interrupter rings 4 which agitate and mix the foam. From foam forming chamber 6, the foam moves on through screen 7 into chamber 8 where it is molded and directed to the target. It is noted that between the exit of chamber 6 and screen 7 the foam passes through expansion chamber 9. This chamber is believed to capture and entrain air with each stroke of the dispenser trigger and is believed to assist in providing a high quality foam. This ability of the nozzle to capture air is considered significant to the ability of this embodiment to effectively function without vents 5.

The foam devices described herein can be fabricated of any convenient thermoplastic material such as polyolefin, including polyethylene and polypropylene, acrilonitrilebutadiene styrene, polyamide, polystyrene, polyvinylchloride, polyvinyl acetate, polyvinylbutyral, and the like. For reasons of ease of fabrication and cost, polypropylene is preferred.

The screen can be of any convenient and useful material whether woven or nonwoven, natural or synthetic; the particular type being selected to provide a foraminous product yielding the desired foam and having a reasonable service life. The screens can be of fine mesh metal or synthetic plastic or can be formed of porous synthetic material where the pores are formed by foaming or other methods known to the art.

The pores in the screens employed can be of any convenient size and configuration to produce foam of the desired character.

In connection with the production of foam it should be noted that the element described herein obtains air in a variety of ways. The design makes use of the fact that liquid product from a trigger-type dispenser already contains some air; makes use of the backflow of air through the screen, as described above in connection with the device embodied in Figure 2 and, finally makes use of air introduced through air passages such as 5. In many cases, air vents 5 can be eliminated.

Another advantage of the element described herein is that foam is generated in a very compact apparatus. The design does not require high length to diameter ratios and it is thus possible to provide a foam generating device that is extremely compact, a feature that is particularly advantageous when consumer product applications and the consequent problems of packaging and shipping are considered.

Additionally, the design is not sensitive to internal spray patterns, permitting a wide viscosity range of materials to be successfully foamed. The device will foam virtually any liquid that can be dispensed in a hand-operated trigger-type dispenser and that contains a surfactant.

The overall dimensions of the foam device are not considered to be critical and can be varied to provide a suitable foam.

Dimensions of one embodiment of the device illustrated by Figure 2 are as follows: the overall length is approximately 2.5 inches (6.35 cm); with the length of the portion attaching to the trigger sprayer (the length to the end of outlet orifice 3) being approximately .6 inches (1.524 cm) and the length from the end of orifice 3 to the centerline of interrupter ring 4 being approximately .25 inches (.635 cm). The distance between centers of the interrupter rings is approximately 0.1 inch (.254 cm).

The distance between the end of outlet 3 and the end of foam forming chamber 6 is approximately .41 inches (1.0414 cm) and the distance from the end of outlet orifice 3 to screen 7 is approximately .5 inches (1.27 cm). The distance from the end of outlet orifice 3 to the end of the nozzle is approximately 1.9 inches (4.826 cm).

Aerating chamber 10 and foam forming chamber 6 have a diameter of approximately .16 inches (.4064 cm) while the outer diameter of chamber 6 is .24 inches (.6096 cm). Expansion chamber 9 has a diameter of .32 inches (.8128 cm). Foam finishing chamber 8 has an inner diameter of .40 inches (1.016 cm).

While the foam generating devices described herein have been illustrated with a trigger-type dispenser, they can be used with a finger pump type dispenser as well.

Further, while the foam generating devices have been described in terms of separate devices that can be attached to a triggertype dispenser, it will be appreciated that the foam generating device can be incorporated into the mold design of a trigger-type dispenser to provide an integral foam dispenser.

WHAT WE CLAIM IS: 1. A foam generating device which comprises a body open at one end to receive liquid pumped from a liquid dispenser and at the other end to dispense foamed product, including within the body: a) a first chamber into which said liquid is introduced in the form of a spray and said liquid is mixed with air, said first chamber having air vents leading to it, b) a second chamber adjacent said first chamber through which said aerated liquid passes, the second chamber being of substantially the same or lesser cross-section than said first chamber, c) a third chamber adjacent to and of larger cross-section than the second chamber and which receives aerated product from said second chamber, d) screening means covering the downstream end of said third chamber and through which the product in the third chamber is forced, and e) outlet means for dispensing the foamed product.

2. The device of claim 1, in which the body is adapted to be secured to the outlet nozzle of a liquid dispenser.

3. The device of claim 1, in which the body is formed with the outlet orifice of a liquid dispenser and the body is adapted to replace the outlet nozzle of said liquid dispenser.

4. The device of claim 1, formed as an integral part of a liquid dispenser.

5. The device of claim 1, 2, 3 or 4, in which said first chamber is provided with aspirating means for introducing air into said chamber.

6. The device of claim 1, 2, 3, 4 or 5, in which said first chamber is provided with one or more wedge-shaped slots for introducing air into said chamber.

7. The device of claim 1, 2, 3, 4, 5 or 6, in which the second chamber is of lesser diameter than said first chamber.

8. The device of claim 1, 2, 3, 4, 5 or 6, in which the second chamber is of substantially the same diameter as said first chamber.

9. The device of claim 1, 2, 3, 4, 5, 6, 7 or 8, in which the second chamber is provided with means for agitating or mixing the aerated product of the first chamber.

10. A foam generating device which comprises a body open at one end to receive liquid pumped from a trigger-type dispenser and at the other end to dispense foamed product, including within the body: a) a first air chamber into which said liquid is introduced in the form of a spray for mixing with air, b) one or more air passages for introducing air into said first air chamber, c) a second chamber adjacent said first chamber, through which the aerated liquid passes, the second chamber being of substantially the same cross-section as said first chamber and being provided with means for mixing the foam, d) a third chamber adjacent to and of larger cross-section than said second chamber and which receives aerated product from said second chamber, e) screening means covering the downstream end of said third chamber, through which the product of the third chamber is forced, and f) outlet means for dispensing the foamed product.

11. The device of claim 1, in which said first, second and third chambers have a common axis, in which said first chamber includes in a wall adjacent said one end of said body an orifice from which said liquid is pumped by said dispenser in the form of a spray of which the axis is substantially coincident with said common axis, in which the cross-sections of said first and second chambers transverse of said axis are substantially the same, and in which transverse of said axis said third chamber has a larger cross-section than said second chamber.

12. The device of claim 11, in which said first chamber is provided with a plurality of slots in the walls thereof, said slots being wedge-shaped and extending in a direction transverse to said common axis, the narrow edge of said slots being in the inner wall of said first chamber whereby to effect an increase in the velocity and turbulence of the air drawn through said slots into said chamber by the movement of said liquid and facilitation of the mixing of said liquid and air to cause preliminary foaming in said first chamber.

13. The device of claim 1, in which said second chamber abuts said third chamber,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Aerating chamber 10 and foam forming chamber 6 have a diameter of approximately .16 inches (.4064 cm) while the outer diameter of chamber 6 is .24 inches (.6096 cm). Expansion chamber 9 has a diameter of .32 inches (.8128 cm). Foam finishing chamber 8 has an inner diameter of .40 inches (1.016 cm). While the foam generating devices described herein have been illustrated with a trigger-type dispenser, they can be used with a finger pump type dispenser as well. Further, while the foam generating devices have been described in terms of separate devices that can be attached to a triggertype dispenser, it will be appreciated that the foam generating device can be incorporated into the mold design of a trigger-type dispenser to provide an integral foam dispenser. WHAT WE CLAIM IS:

1. A foam generating device which comprises a body open at one end to receive liquid pumped from a liquid dispenser and at the other end to dispense foamed product, including within the body: a) a first chamber into which said liquid is introduced in the form of a spray and said liquid is mixed with air, said first chamber having air vents leading to it, b) a second chamber adjacent said first chamber through which said aerated liquid passes, the second chamber being of substantially the same or lesser cross-section than said first chamber, c) a third chamber adjacent to and of larger cross-section than the second chamber and which receives aerated product from said second chamber, d) screening means covering the downstream end of said third chamber and through which the product in the third chamber is forced, and e) outlet means for dispensing the foamed product.

4. The device of claim 1, formed as an integral part of a liquid dispenser.

the abutting relation being such as to provide a nozzle at the inlet through which said third chamber receives aerated product from said second chamber.

14. A foam generating device constructed substantially as described with reference to Figures 1 and la of the accompanying drawings.

15. A foam generating device constructed substantially as described with reference to Figures 2 and 2a of the accompanying drawings.