Foamer nozzle assembly for trigger sprayer

Abstract: A foamer nozzle assembly comprises a turbulence chamber (34) with a foam enhancer comprising a plurality of spaced ribs (37,38) defining openings (39), the ribs having flat surfaces lying perpendicular to the inner wall (33) of the chamber for further generating foam as the foam bubbles impact against such flat surfaces to further mix with the air in the turbulence chamber. The ribs (37,38) may lie in a common plane and intersect to form square openings, or may consist of first and second sets of ribs lying in respective spaced apart parallel planes. The ribs of the first set may extend parallel, perpendicular or obliquely to the ribs of the second set. A third set of ribs may interconnect the ribs of the first and second sets.

Description: This invention relates generally to foamer nozzles for trigger sprayers, and more particularly to foamer nozzles having a turbulence chamber for creating foam in combination with a molded plastic grating to enhance foaming. Pump sprayers capable of dispensing especially household cleaning product formulations as a foam are enjoying increased demand, and foam dispensers of various types are known in the art. There is a continuing effort by the product manufacturers to increase the effectiveness of their solutions. This generally means an increase in the concentration of the active ingredient and in the time the product hangs on the predominantly vertical target surfaces. With household cleaners, which may include bleach based solutions, the vapor produced when sprayed in a small enclosed space of a bathroom or shower may cause severe burning of the nose, mouth and eyes. Some foamers on the market produce a reasonably acceptable foam quality but also introduce a large amount of airborne droplets into the atmosphere which give rise to such produced vapors. Some other foamers may significantly reduce the amount of airborne particles but do not produce an optimal foam. A foam generating pump sprayer is disclosed in U.S. Patent No. 4,603,812 as having a foam-forming device which includes a wire mesh screen retained in the path of the spray such that substantially all the spray passes through the foam forming device without contact except by the screen. A foamer nozzle disclosed in U.S. Patent 4,768,717 has a wire mesh screen disk in combination with a turbulence chamber to enhance the foam-producing capabilities of the nozzle. A foam nozzle assembly disclosed in U.S. Patent 4,925,106 has a perforated wall in combination with a foam generating chamber, the wall having ribs and slots therein and the back edges of the positions of the ribs between slots being rounded to provide a surface upon which the conical spray can impinge and be deflected in different directions to mix with air in a foam generating chamber to create foam. Foamer nozzles are disclosed in U.S. Patents 4,883,227 and 4,971,252 as having impingement protuberances within a turbulence chamber for creating foam. According to one aspect of the present invention there is provided a foamer nozzle assembly mounted at a discharge end of a trigger sprayer, comprising, an inner cylinder having a smooth inner wall defining a turbulence chamber coaxial with a discharge orifice located in an end wall at said discharge end through which a conicle spray is discharged in a downstream direction into said chamber for generating foam as spray particles impact against said smooth inner wall to mix with air in said chamber to form foam bubbles; characterised in that, foam enhancement means of molded plastic construction is located in said cylinder adjacent the downstream end thereof, said means comprising at least first and second sets of spaced apart ribs respectively lying in first and second parallel planes, said ribs having flat surfaces lying perpendicular to said inner wall and facing upstream for further generating foam as the foam bubbles impact against said flat surfaces to further mix with the air in said chamber to create foam ejected from said enhancement means, and said ribs having opposing sides of a length greater than the width of the flat surfaces thereof facing upstream for further accelerating the turbulent flow of foam bubbles along the opposing sides. The preferred embodiment of the present invention provides a foamer which significantly reduces the amount of airborne droplets into the atmosphere while at the same time creates an acceptable quality foam which does not dribble when applied to the target and which hangs to the target through an acceptable interval. The ribs are preferably trapezoidal in cross-section; and in both said sets, the ribs preferably extend only in a common direction. In such an arrangement, it is also preferable for the ribs of said first set to be equally spaced apart, and for the ribs of said second set to be equally spaced apart and offset relative to the ribs of said first set by a distance substantially equal to one-half the spacing of the ribs of said first set. The first set of ribs may be located downstream of said second set, the opposing sidewalls of the ribs of said first set converging in a downstream direction, and the opposing sidewalls of the ribs of said second set diverging in said downstream direction. The foam enhancement means may also further comprise a third set of ribs interconnecting with and extending in a direction perpendicular to said first and second sets. In this arrangement, said first set is preferably located downstream of said second set, the ribs of said third set intersecting with the ribs of said second set and extending downstream of the ribs of said first set. The arrangement may also be such that the ribs of said third set are zigzag-shaped in said perpendicular direction. The ribs of said first and second sets may be contiguous and extend in mutually perpendicular directions. In this arrangement, the ribs of said first and second sets are preferably rectangular in cross-section. Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings. Figure 1 is a vertical sectional schematic view of the foamer nozzle assembly of the invention mounted at the discharge end of a trigger sprayer; Figure 2 is a view of one embodiment of a foam enhancer according to the invention taken substantially along the line 2-2 of Figure 1; Figure 3 is a view taken substantially along the line 4-4 of Figure 2; Figure 4 is a view similar to Figure 2 of another embodiment of a foam enhancer according to the invention; Figure 5 is a view taken substantially along the line 6-6 of Figure 4; Figure 6 is a view similar to Figure 2 of still another embodiment of a foam enhancer according to the invention; Figure 7 is a view taken substantially along the line 8-8 of Figure 6; Figure 8 is a view similar to Figure 6 of a further embodiment of the invention; and Figure 9 is a view similar to Figure 8 of a still further embodiment of the invention. Turning now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views, a trigger pump sprayer generally designated 10 is shown in Figure 1 of known construction as having a trigger actuator 11 and a discharge end 12 into which liquid product flows through a discharge passage 13 upon pumping operation. A rotatable nozzle cap 14 having a central discharge orifice 15 is snap-fitted about the discharge end as at 16. The cap has an internal sleeve 17 in engagement with a probe cap 18 carrying an annular discharge flap valve 19. The probe cap is fixed to the end of a probe 21, and has a swirl chamber 22 formed at its outer end. Longitudinal grooves 23 and 24 on the probe cap and sleeve 17 are aligned upon relative rotation of the nozzle cap for admitting liquid product via the discharge valve through tangential channels 25 into the swirl chamber upon pumping action of the sprayer for inducing a swirl to the product to issue through the discharge orifice as a conical spray. The foamer nozzle assembly 26 according to the invention includes a foamer cap 27 having an outer skirt 28 formed with air aspiration openings 29, and a plurality of snap-lock legs (not shown) extending from skirt 28 for snapping into suitable openings (not shown) located in end wall 31 on nozzle cap 14 which contains discharge orifice 15. Such a snap fit arrangement is illustrated in U.S. patent No. 5,366,160, commonly owned herewith. The foamer cap has an inner cylinder 32 coaxial with the discharge orifice, the cylinder having a smooth inner wall 33 terminating a predetermined distance from end wall 31. Cylinder 32 defines a turbulence chamber 34 such that, during pumping, the conical spray impacts against inner wall 33 of the turbulence chamber thereby creating and concentrating a foam as the spray particles mix with the air in the turbulence chamber as aspirated through air openings 29. The production of foam is enhanced by the provision of foam enhancement means 35 shown schematically in Figure 1. According to one embodiment of the invention, the foam enhancement means 35 is shown in Figures 2 and 3 in the form of a grate or grid 41 mounted within cylinder 32 adjacent its downstream end 36. The grid comprises a plurality of ribs 37 and 38 each extending in a common direction, such as horizontal. Ribs 37 are parallel to one another and are mutually spaced apart to define uniform openings 42, of a first set of ribs. Similarly, ribs 38 are parallel to one another and are mutually spaced apart to define uniform openings 43 of ribs in a second set. The first and second sets of ribs are relatively offset (in a vertical direction illustrated in the drawings) a distance substantially equal to one-half spacing 42 or 43, such that the net spacing of ribs between the two sets defines openings 44, as shown in Figure 2. With this arrangement, larger spacings 42 and 43 of the ribs in the respective sets simplify the tooling and molding operations and yield an effective spacing 44 which is substantially one-half either spacing 42 or 43. The two sets of ribs lie in spaced apart planes, the back surfaces of the ribs (i.e. the rib surfaces facing the discharge orifice) of both sets being flat. The ribs 37 and 38 may be trapezoidal in section, with the opposing sidewalls of the ribs of the first set converging in a downstream direction, and the opposing sidewalls of the ribs of the second set diverging in the downstream direction. Of course, ribs 37 and 38 of both sets can be so oriented that their opposing sidewalls either converge in the downstream direction or both diverge in the downstream direction. The flat surfaces of the ribs confronting the turbulence chamber provide impact surfaces for the foam bubbles created in the chamber, enhance the foaming formation, and facilitate virtually unimpeded discharge of foam through the grid outwardly of end 36 of the foamer nozzle. A further embodiment of the foam enhancer 35 according to the invention is shown in Figures 4 and 5 in the form of a screen 45 similar to that of grid 41 in that it includes first and second sets of relatively offset ribs 37 and 38 lying in spaced planes and the ribs being spaced apart as at 42 and 43. In addition, a third set of mutually spaced apart ribs 46 extend in a direction perpendicular to the common direction along which ribs 37 and 38 extend. Ribs 46 and zigzag-shaped and are molded to intersect with horizontal ribs 38 while extending behind or downstream of ribs 37, as shown in Figure 5. The mutually spaced ribs of the three sets define openings 47, shown in Figure 4. The back faces of the ribs 46 are flat and may be trapezoidal in section with the opposing sidewalls thereof either converging or diverging in the downstream direction. The tooling and molding operations for producing screen 45, which may be integrally formed with the foamer nozzle, are less complicated and less costly by reason of the unique mesh construction primarily in permittings a greater mutual spacing between the respective ribs 37 and 38 with a net effective spacing in that direction of one-half the initial spacing. The foam enhancer of Figures 4 and 5 functions to enhance foaming formation in a manner similar to that as described with reference to Figures 1,2 and 3. A still further embodiment of the foam enhancer 35 according to the invention is shown in Figures 6 and 7 as a screen 48 including first and second sets of ribs 49 and 51 respectively lying in parallel planes and formed integrally at opposing ends with inner wall 33 of cylinder 32. Ribs 49 and 51 are contiguous, the ribs of each set being respectively parallel and extending in mutually perpendicular directions forming rectangular openings 52 between the ribs of the two sets. And, ribs 49 and 51 are each rectangular in cross-section with the longer sides 53 thereof (Figure 7) extending along the downstream direction of product flow from the discharge orifice. The disposition of the longer sides of the ribs along the flow path enhances the foaming formation as the foam bubbles concentrated in turbulence chamber 34 first impact against the flat surfaces of ribs 51, glide along sides 53 of ribs 51 which accelerate the turbulent flow as the foam bubbles then impact against the flat surfaces of ribs 49 and glide along sides 53 thereof which further accelerate the turbulent flow. The foam further mixes with the air in chamber 34 to enhance the generation of foam which passes through screen 48 to the target. The variant shown in Figure 8 is similar to that of Figure 6 except that ribs 5 la lie at an angle other than perpendicular to ribs 49 thereby presenting non-rectangular openings 52a. Otherwise, the openings 52b presented by the two sets of ribs can be non-uniform as in Figure 9. Many modifications and variations of the present invention are made possible in the light of the above teachings. For example, the ribs of Figures 2,3 embodiment can extend in a common direction which is vertical or in some other common angular direction, without departing from the invention. Otherwise, the ribs of one or both sets in any of the aforedescribed embodiments can be spaced apart to present non-uniform openings therebetween, in accordance with the invention. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Claims: A foamer nozzle assembly mounted at a discharge end (12) of a trigger sprayer (10), comprising, an inner cylinder (32) having a smooth inner wall (33) defining a turbulence chamber (34) coaxial with a discharge orifice located in an end wall (31) at said discharge end (12) through which a conical spray is discharged in a downstream direction into said chamber (34) for generating foam as spray particles impact against said smooth inner wall (33) to mix with air in said chamber (34) to form foam bubbles; characterised in that, foam enhancement means of molded plastic construction is located in said cylinder (32) adjacent the downstream end thereof, said means comprising at least first and second sets of spaced apart ribs (37,38) respectively lying in first and second parallel planes, said ribs (37,38) having flat surfaces lying perpendicular to said inner wall (33) and facing upstream for further generating foam as the foam bubbles impact against said flat surfaces to further mix with the air in said chamber (34) to create foam ejected from said enhancement means, and said ribs (37,38) having opposing sides of a length greater than the width of the flat surfaces thereof facing upstream for further accelerating the turbulent flow of foam bubbles along the opposing sides. The foamer nozzle assembly according to claim 1, wherein said ribs (37,38) are preferably trapezoidal in cross-section. The foamer nozzle assembly according to claim 2, wherein said ribs (37,38) in both said sets extend only in a common direction. The foamer nozzle assembly according to claim 3, wherein said ribs (38) of said first set are equally spaced apart, and said ribs (37) of said second set are equally spaced apart and are offset relative to said ribs (38) of said first set a distance substantially equal to one-half the spacing of said ribs (38) of said first set. The foamer nozzle assembly according to any of claims 2 to 4, wherein said first set is located downstream of said second set, the opposing sidewalls of said ribs (38) of said first set converging in a downstream direction, and the opposing sidewalls of said ribs (37) of said second set diverging in said downstream direction. The foamer nozzle assembly according to any of claims 2 to 5, wherein said means further comprise a third set of said ribs (46) interconnecting with and extending in a direction perpendicular to said first and second sets. The foamer nozzle assembly according to claim 6, wherein said first set is located downstream of said second set, said ribs (46) of said third set intersecting with said ribs (37) of said second set and extending downstream of said ribs (38) of said first set. The foamer nozzle assembly according to claim 6 or claim 7, wherein said ribs (46) of said third set are zigzag-shaped in said perpendicular direction. The foamer nozzle assembly according to claim 1, wherein said ribs (37,38) of said first and second sets are contiguous and extend in mutually perpendicular directions. The foamer nozzle assembly according to claim 9, wherein said ribs (37,38) of said first and second sets are rectangular in cross-section. The foamer nozzle assembly according to claim 1, wherein said ribs (37,38) of said first and second sets are contiguous and extend in mutually angular, non-perpendicular directions. The foamer nozzle assembly according to any preceding claim, wherein said ribs (37,38) of said first and second sets are spaced apart to define uniform openings therebetween.

Inventors: DOBBS DOUGLAS B, SPATHIAS ADONIS, DOBBS, DOUGLAS B., SPATHIAS, ADONIS
Applicants: CALMAR INC, CALMAR INC.
Application year: 1995
Main classification: B05B11
IPC codes: B05B11, B05B1, B05B7