Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1. FIEED OF THE INVENTION
The invention relates to an element for use in conjunc-
tion with a liquid dispenser, preferably of the trigger type or
finger pump type which element causes the product to be dis-
pensed 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 Numbers 917,135, 1,315,866 and 1,331,842 which
correspond to U.S. Patents 3,016,202, 3,685,739 and 3,650,473,
respectively.
2. RELEVANT PRIOR ART
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.
Thus, in accordance with the present teachings, a
foam generating element is provided which comprises a body
means adapted at one end to receive a liquid pump from a liquid
dispenser and at the other end to dispense foamed product.
The element includes a first chamber within the body means
whereby the liquid is mixed with air, a second chamber is
provided adjacent the first chamber through which the aerated
liquid passes, the second chamber is of substantially the
same or lesser diameter than the ~irst chamber. A third
chamber is provided adjacent to and of larger diameter than
the second chamber and receives aerated product from the
second chamber. Screening means is provided covering the
downstream end of the third chamber and through which the
product in the third chamher is forced and outlet means is
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provided for dispensing the foamed product.
In accordance with a further embodiment, a foam
generating device is provided which comprises a body open at
one end to receive liquid pumped from a liquid dispenser at
the other end to dispense foam product, including within the
body:
(a) a first chamber into which the liquid is introduced
and mixed with air to initiate foam generation,
(b) a second chamber adjacent the first chamber through
which the initially generated foam and aerated liquid passes,
the second chamber being of substantially the same or lesser
cross section than the first chamber and being provided with
means for generating more foam of finer texture,
(c) a third chamber adjacent to and of larger cross
section than the second chamber and which receives aerated and
foamed product from the second chamber,
(d) screening means covering the downstream end of
third chamber and through which the product in the third
chamber is forced, and
(e) outlet means for dispensing the product as a
foam.
By yet a further teaching a foam generating device
is provided 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 chamber into which the liquid is
introduced for mixing with air,
~b) one or more air passages for introducing air
into the first chamber,
(c) a second chamber adjacent the first chamber,
through which the aerated liquid passes, the second chamber
being of substantially the same cross section as the first
~ -2a-
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chamber and being provided with means for generating foam,
(d) a third chamber adjacent to and of larger cross
section than the second chamber and which receives aerated and
foamed product from said second chamber,
(e) screening means covering the downstream end of
the third chamber through which the product of the third
chamber is forced, and
(f) outlet means for dispensing the foamed product.
DESCRIPTION OF THE 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 the right side.
Figure 2 is a longitudinal sectional view of the pre-
ferred embodiment of this invention and Figure 2a is a view
of this embodiment as seen from the right side.
DESCRIPTION OF THE INVENTION
The foam producing elements are, in the embodiment of
this invention illustrated by Figures 1 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 la, 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 102. Contained within
body 101 is aspirating chamber 104 of
-2b-
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generally cylindrical shape which ~buts dispenser nozzle 103 and which is provid-
ed wlth aspirating slots 105. S~ots 105 cooperate with slots 106 located in the
body to introduce air into liquid maving through chamber 104. It should be noted
that slot 106 defined by the dotted lines in Figure 1 wculd not nDrmally appear
in a sectional drawing' their presence however, helps to illustrate the oommuni-
cation between inner chamber 104, aspirating slots 105 and the atmDsphere. Body
lOl is also provided-with fo3m-fcDmin~icha~ber 107 of cylindrical shape, having
a diameter or cross section less than chamber 104, which chamber 107 abuts an
expansion chamher 108. EXpansion chamDer 108 is located between chamber 107 and
screens 110' foan molding chamber 111 follows the screens. The diameter or
cross section of expansion chao~Der 108 is substantially larger than that of
foamrforming 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
- chamDer 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 b dy to a dispenser, thereby
; eliminatLng the separate nozzle illustrated ~y 102 in Figure 1. m e other open-
ing defines chamber 8 which mDlds the fa~m and ~;rects it to its target. Chamber
8 terminates with screen 7, which is interposed ketween chamber 8 and e~pansion
ch~mber 9. This chamber has a larger diametPr or crDss section than foam-forming
chamker 6 which abuts, the abutting relation being such as to provide a n~zzle
at the inlet bo expansion chamber 9, as shown in the drawing. Chamber 6 is
generally cylindrical an~ contains one or more inberrup*er rings 4 which are
constrictions formed in the wall o~ the chamber and func*ion to agitate and hLmD-
genize the foam entering fm m aspirating chamber 10. Cbmmunicating between
chYm~aer 6 and orifi oe 3, chamber 10 is optionally provided with one ar mDre
~ wedge-shaped aspirating ~lots 5 thr~ugh which air is drawn into aspirating cham,
~er 10 by the mavement of liquid therethrough. Chamker 10 abuts orifice 3 thr.
ough which liquld is forced by the dispenser.
The foam prodNcing elements of the invention are si~ple to fabricate
and are effective in ~enerating foam. The element illustrated by Figure 1 is
fakricated in five parts, bcdy 101, holders 109 and screens 110. The element
illustrated by Figure 2
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is fabricated in two parts, ~ody 1 and screen 7. ~1anufacture of
molds for production of body members 1 and 101 is a straightforward
proposition and prevents no difficulties. Similarly, insertion of
holders 109 and screens 110 in the device of Figure 1 and the in-
sertion of screen 7 in a device of Figure 2 are straightforward.
Screen 7 is conveniently fastened to body member 1 in any con-
venient manner and, where t-he screen and body mem~er 1 are of the
same material, such as polypropylene, attachment is readily done
by sonic welding.
Turning to the element 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 ~rought 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 cham~er 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 unaccepta~ly high amount of pressure to operate the
trigger-type dispenser. Where two screens are used, they should
be spaced apart, at least .~31 inches (.0787 cm) to facilitate
3~ the formation of a fine textured foam. If the screens are too
close, they perform li~e a single screen, while if the screens
are too far apart, the flow of foam is slowed and the foam can
~egin to break down before it has passed through the device.
On passing through the screens, the foam passes through
cham~er 111 where the foam is finally molded and directed to the
target.
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The character o the foam produced, that is, wet or dry,
is primarily a function of the air to liquid ratio and is generally
governed by liquid coming through orifice 103, the amount of air
coming in through vent 105 and the size of aspirating chamber 104.
Where the trigger-type dispenser has an adjustable nozzle, the
adjustment usually provides a stream of liquid or a spray. This
adjustment is a convenient means for governing the type of foam.
Where the nozzle is set for a spray, the liquid leaving orifice
103 tends to spread or flare. The ratio of air to liquid in
chamber 104 is therefore relatively high and the.resulting foam
tends to be drier and creamier. Where the dispenser nozzle is
set for a stream, the liquid entering the foam element via orifice
103 tends to be compressed and the ratio of air to liquid in
chamber 104 is relatively lower; the foam produced 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 element 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
ad~ustable nozzle of a trigger-type 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
be]ieved 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.
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The foam elements described herein can be fabricated of
any convenient thermoplastic material such as polyolefin, in-
cluding 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 non-woven, natural or synthetic; the particular
type being selected to provide a foraminous product yielding the
iO 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 foam-
ing or other methods known to the art. The pores in the screens
employed can be of any convenient size and configuration to pro-
duce foam of the desired character.
In connection with the production of foam it should be notedthat the element described herein obtains air in a variety of
ways. The desi~n 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 ~ 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 element that is extremely compact, a
feature that is particularly advantageous when consumer product
applications and the consequent problems of pac~aging 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.
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The overall dimensions of the foam element are not considered
to be critical and can be varied to provide a suitable foam.
Dimensions of one embodiment of the element illustrated by Figure
2 are as follows: the overall length is approximately 2.5 inches
(6.35 cm); with the length o~ the portion attaching to the trigger
sprayer (the length to the end of outlet orifice 3) being approx-
imately .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 di-
ameter of approximately .16 inches (.4064 cm) while the outer
diameter of chamber 6 is .24 inches (.6096 cm). Rxpansion
chamher 9 has an outer diameter of .32 inches (.8128 cm). Foam
finishing chamber 8 has an inner diameter of .40 inches (1.016 cm).
While the foam generating element described herein has been
illustrated with a trigger~type dispenser, it can be used with a
finger pump tvpe dispenser as well. Further, while the foam
generating element has been described in terms of a separate
element that can be attached to a trigger-type dispenser, it will
be appreciated that this foam generating element can be incorporated
into the mold desing of a trigger-type dispenser to provide an
integral foam dispenser,
