Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR DISPENSING A NON-FLUID CHEMICAL PRODUCT
The present invention relates to a device for
dispensing a non-fluid chemical product as a dosing liquid
S comprising a solution and/or suspension thereof in a
solvent, of the kind wherein the device is separated by a
liquid-pervious screen, into an upper chamber in which the
product is to be held, and a lower chamber provided with
an inlet for the solvent and an outlet for the dosing
liquid.
One particular application for this type of dispenser
is in the dispensing of non-fluid detergent materials into
mechanical warewashing or fabric-washing machines,
although the present invention is not limited to these
applications, as many others can readily be envisaged.
In commercial washing institutions, where frequent
dosing of detergent products from large supply containers
is general practice, dispensers both inside and outside
the washing machines are widely employed and the proper
and sa~e functioning thereof is of the utmost importance.
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One particular type of detergent product for use in
commercial washing machines comprises various liquid
compositions, i.e. dissolved or dispersed products. These
have been popular from the point of view of transport,
easy formulation and good storage properties. However,
recently, there has been an increase in interest in
non-fluid products for improvement in reliability,
especially for the purpose of providing uniform
concentrations of product in the wash liquor.
In the art, a number of impro~ements have been
proposed pertaining to dispensers for powder and other
solid form detergent products. Some of these have been
known for a very long time. For example, US patent
2,686,080 describes impregnating water running from a tap
by directing it through a chamber containing a soap bar.
US patent 2l135,969 describes passing water through a
chamber in which soap flakes are held in a mesh cage, and
supplving the resultant solution to a bathroom shower.
More recent developments have mainly been in the
me_hanical warewashing field. US patent 4,462,511
(Viking) describes dosing a caustic powder product
retained by a screen over the mouth of a up-turned
container, into which water is sprayed. European
speci~ication EP 58,507 (Berelson~ describes a two-part
container divided by a mesh, particles of dishwashing
powder being held above the mesh and a spray head being
situated below it. Spraying water over a solidified block
prod~ct held in a container is described in European
specification EP 20,709 ~Economics Laboratory).
All of the aforementioned known systems suffer from
the disadvantage that they are designed for coupling
in-line between the water supply and the point of use.
The later developments specifically intended for
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mechanical warewashing, involve use of a spray-system to
ensure uniform dispensing behaviour.
We have found that a simpler construction, which yet
avoids these disadvantages, is possible if the inlet of
the device is connected to a mouth for recei~ing the
solvent in free space, whereby the solvent can flow into
and fill the lower chamber to a level where it permeates
the screen to take-up the product thereabove, whereafter it
flows back into the lower chamber to exit via the outlet
as the dosing liquid.
In its simplest form, the present invention may be
realised as a unitary construction, manufactured from
relatively inexpensive materials not involving any
electrical components, which can be produced either as a
refillable dispenser or as a disposable (throw-away-after-
use) package. In some embodiments, the outlet merely may
be an opening in the device so that during use, the supply
of water is caught by the mouth and the dimensions of the
inside of the device are such that during operation, the
throughput is approximately constant, resulting in a
substantially uniform concentration of the product in the
exuded dosing liquid.
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In ~nother (preferred) ~orm, the outlet is provided
with a gate which when closed, allows saturation of the
product by the solvent as the device is filled.
Subsequently, when the gate is opened, a batch o~ dosing
liquid is released, which is more concentrated than that
produced during the continuous operation described in the
previous paragraph. In this kind of non-continuous
operation, opening and closing of the gate may be
controlled by a remote means, e.g. through a mechanical,
~lydraulic or electrical linkage. These may be operated as
desired, for example according to a predetermined
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programme, or in response to a temperature-sensitive
element. The latter is appropriate when the device is
intended for operation inside washing (warewashing or
fabrics-washing) machines. In the latter instance, it is
also possible for the gate to be provided with a
thermomechanically operated element so that operation of
the gate is automatic upon sensing of a predetermined
temperature in its vicinity.
1~ Although not absolutely necessary, it is preferred
that the upper chamber is closed. In this way, the upper
chamber ldisposed above the screen) provides an air trap
in which, during use, the product is located. However,
most preferably, the upper chamber is then provided with a
lid which must be substantially sealable (air-ti~ht) to
preserve the air trap function of said upper chamber.
The filling of the chamber to the level sufficient
for the solvent to permeate the screen to contact the
chemical product, will in general be determined by the
dimensions of the mouth, the inlet, outlet and the inside
of the lower chamber, as well as the flow rate of liquid
entering the mouth. However, especially, but not
exclusively, in the case of the aforementioned continuous
~5 oparation, it is preferred if the mouth is situated above
the level of the screen. This tends to ens~re that the
lower chamber is always filled to the required level to
ensure proper and uniform up-take of the product.
For the avoidance of doubt, all references herein to
"leveln, "height" and "upper" and "lower" chambers are
defined in terms of the normal and intended orientation of
the device in use and does not limit the claims solel~ in
terms of the device when so positioned. In fact, all
dimensional restrictions are to be construed in this
light.
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Simplified and low-cost construction is facilitated
if the device is manufactured with the mouth connected to
the inlet by a channel integral with the upper and lower
chambers, and separated from the former by a dividing
wall. In the most preferred construction, the device is
in the form of a rectangular box having two opposing
square or rectanyular side walls and two narrower,
opposing rectangular side walls, with the channel running
vertically along one side parallel to or contiguous with,
one of said narrower side walls, up to the mouth which is
flush with the top of the device.
It should also be noted that whatever the form of
construction, during the intake of solvent and discharge
of dosing liquid, the second compartment defines a
flow-path adjacent the screen. To improve the contaet
between the solvent and the chemieal produet supported by
the sereen, it is preferred to ineorporate means for
eausing turbulenee in~the flow-path. For example this may
take the form of cross-ribs in one or more of the walls of
the lower chamber, partially blocking the flow-path.
The device may be used for dispensing any non-fluid
ehemieal product which can be dissolved and/or dispersed
in the solvent in question. The term "non-fluid" is
intended to exclude products which would simply run
through the liquid-pervious screen, especially liquids.
~he term does however inelude various solid, near-solid,
paste and gel produets whieh can be retained above the
sereen lwhich'of course may be varied also to suit the
partieular product). In particular, the term ineludes
physieal forms such as powders, (notwithstanding that
powders are sometimes in other contexts termed "fluids" in
that they are pourable), granulates, solid bloeks, stieks,
"noodles", other extruded ~orms and the like. They may be
of either homogeneous or heterogeneous consisteney. In
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general, a main requirement is that the size of any
particles, must be greater (at least for most particles)
than the size of the holes in the screen.
The mesh may be of any material compatible with the
chemical product and solvent in question, and may be
porous such as is blotting paper, a non-woven fabric or
sinter glass, or may have a mesh which can be either fine,
such as found in various woven fabrics, or wide, such as a
netting or mesh, e.g. of wire or plastics material. ~or
example, for use with powders, the holes in the mesh may
be in the order of 0.5 x 0.5 mm, or with noodles, 0.5 x
0.5 cm, or with sticks, 2 cm x 2 cm.
As stated, the device according to the invention will
be applicable to a wide range of applications which may
readily be appreciated in the light of the present
disclosure. Although not limited thereto, it is however
particularly suited to location in washing machines,
especially for fabrics washing, and more especially
mechanical warewashing. In this situation, of course the
solvent will normally comprise substantially only water
and the chemical product will be a detergent and/or
caustic composition, optionally containing the usual
~5 products such as bleaches, enzymes and the like. For
these uses, it is particularly preferred that the upper
chamber has a closed top and side walls and the screen is
disp~sed in a bottom wall thereof, the lower chamber being
disposed beneath and substantially peripherally
co-terminous with the screen. For support inside a
washing machine, the device may be provided with a support
means such as a hook, cord or any other feature which may
readily be envisaged. Another application where the
solvent is not water but is a volatile organic liquid, is
in the dosing of adjuncts in dry cleaning.
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Although a major advantage o~ the present invention
is that it can be located inside a washing machine, rather
than in-line, it can also be located outside the machine,
e.g~ in a by-pass unit in the water supply system.
It should also be appreciated that the aforementioned
systems described in US 4,4~2,511, EP 58,507 and EP 20,709
all employ jets to spray the held solid, the jet size and
dimensions being tailored according to ~he required fl.ow
rates so that the dissolved or dispersed product simply
falls away from the bulk of the ma~erial, but there is no
chamber filled with water and the mechanism of product
dispensing is not by way of permeation through a scrRen.
Thus, according to a further aspect of the present
invention, we may also claim a method of dispensing a
non-fluid chemical product as a dosing liquid comprising a
solution and/or dispersion thereof in a solvent, by
providing a device separated b~ a liquid-pervious screen
into an upper chamber in which the product is held, and a
lower chamber provided with an inlet for the solvent and
an outlet for the dosing liquid, and supplying solvent to
said inlet at a rate whereby the solvent flows into and
fills the chamber to a level where it permeates the screen
to take-up the product thereabove, whereafter it flows back
~5 into the lower chamber to exit via the outlet as the
dosing liquid.
Although this method is not limited to being
performed with the device according to the invention (as
hereinbefore described) it is pre~erred that the solvent
is received in free space by a mouth, connected to said
inIet.
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It should also be mentioned that in devising the
present invention, the applicants envisaged constructions
based on permeation through liquid-pervious screens,
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whereby the product is in a chamber below or to one side
or another of the other chamber forming a flow-path.
However, this would result in non-uniform dispensing an~
incomplete usage of the stock product. However, it should
be further noted that in the context of the present
invention, references to the "upper" and "lower" chambers
do not e~clude constructions whereby the device is used
with an upper chamber positioned or angled somewhat to one
side of the lower chamber, which is still generally
positioned at a lower level.
The invention will now be described in more detail
and with reference to the accompanying drawings in which -
Figure 1 shows a detailed perspective view of a
device according to the present invention, the front
wall being shown partly cut-away.
Figure 2 shows a less detailed, alternative
perspective view of the device in Figure 1,
illustrating better, the opening of the lid and with
the outlet in a different position.
Figure 3 shows in schematic view, a washing machine
containing the device shown in Figure 1 or Figure 2.
The device 1 comprises a top wall 2, side walls 4, 5,
6 and a bottom wall 7. A first upper chamber 8 is defined
by the top wall 2, the side walls 3, 4, 6, a dividing wall
9 and a bottom screen 10. The top wall 2 comprises a lid
11 pivoting along a hinge 12 and having a knob 13 for
opening and closing. A second lower chamber 14 is defined
by the side walls 3, 4, 6, the bottom wall 7, the dividing
wall 9 and the screen 10. A channel 15, between the side
wall 5 and the dividing wall 9 of the compartment 14
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connects a mouth 16 for receiving water, and an inlet 14a
to the lower chamber. The latter is also provided with an
outlet 17, egress from which is controlled by a gate 18
(details not shown)~ The upper chamber 8 comprises a
non-fluid product (also not shown) which is introduced
through the lid 11 and supported by the screen 10, the
mesh size of which is sufficiently small not to have
undissolved non-fluid product falling through.
Figure 2 shows the same device as Figure l, the
outline 22 delineating the locus of the lid as it is
opened. Also, in this case, the outlet of the lower
chamber is situated at the bottom of the narrcw side wall
3.
As shown in Figure 2, the device may be suspended
under the supply water spraying line 19 of a washing
machine 20, the mouth 16 being immediately below a
spraying nozzle 21. Suitable means (not shown) such as a
cord or hook are provided for this purpose.
When non-discharging, the lower chamber 14 will be
completely filled with water. Owing to the fact that the
top wall 2, the side walls 3, 4, 6 and the dividing wall 9
are closed, the upper chamber 8 forms an air trap cavity
and water is not introduced therein to any significant
extent. Only the down-most layer of the non-fluid product
therein is wetted owing to contact through the screen 10
with the water in the lower chamber 14. In this way, slow
dissolving of non-fluid product is facilitated.
During supply water intake or recycling of the wash
bath solution, any oversupply of water/solution from the
spraying nozzle 21, immediately above the mouth 15,
results in the latter simply functioning as an overflow.
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The operation of the device according to the present
embodiment, is fully dependent on the control of the
outlet 17 by the gate 18 and the timing of the water
supply to the device.
Accordingly, if relatively concentrated doses of
product solution are desired, egress from the lower
chamber 14 is controlled such that, after the previous
discharge of solution, this chamber is filled with water
and the egress of solution is blocked during a period in
which a gradual build-up of the product concentration can
take place. At this point there is saturation of the
product, at least the lower ]ayers thereof, with the
water. Depending on the length of this period, a more or
less concentrated solution can be es~ablished for release
as a batch when the gate is opened.
If, on the other hand, only relatively low
concentrations of product are required, it may be
sufficient to use the device simply as a flush-through
unit and have the outlet 17 in the open position all the
time (or to omit the gate altogether). Product
dissolution will then only take place during water intake,
the lower chamber 14 defining a flow-path along the screen
~5 10.
It will be evident that the above two modes of use
can be combined or applied in some alternating pattern to
achieve product dispensing and concentration control as
desired. Depending on the specifics of the wash programme
and the consequent ingress and egress of water/solution, a
whole range of product concentration levels can be
established.
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