Note: Descriptions are shown in the official language in which they were submitted.
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Water-Jet Injection Device For Dispensers
The present invention relates to a water-jet injection
device in dispensers for making and dispensing mixtures of
water and another free-flowing substance, in particular
mixed drinks.
An example of such a water-jet injection device having a
water-jet tube of the kind in question herein is known from
DE 36 07 623 A1, published September 10, 1987, in Germany.
The water-jet tube of this water-jet injection device is
inserted into the injector housing, i.e. in the end
connected with a water supply portion or part, in such a
way that the outlet end of the water-jet tube freely
projects into a mixing chamber in the injector housing. An
automatically opening valve can connect the mixing chamber
with a supply container for the freely-flowing substance
which is drawn into the mixing chamber by the action of the
water jet leaving the water-jet tube. The mixture from the
mixing chamber enters an inlet end, opposite the outlet end
of the water-jet tube, of a nozzle and diffusion section,
from which the mixture is discharged through a dispensing
section.
Such water-jet injection devices are used in drink
dispensers, for example. Between individual dispensing
operations there may be intervals of varying length, during
which the mixing chamber remains filled with residues from
the mixture in that preceding dispensing operation. There
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is a risk that parts of this mixture may diffuse through
the water-jet tube into the water in the water-supply
section. This could result in hygienic problems, because
microorganisms may develop, for example. In the mixing
chamber, itself, the mixture still has a relatively high
concentration of the free-flowing substance, but the
concentration decreases due to dilution during diffusion
into the water supply section. This further accentuates
the hygienic problem.
Although attempts have been made to separate the water-jet
injection device from the water supply section by a non-
return valve during the intervals between dispensing, the
hygienic problems can only be reduced to a limited extent,
since the distance between the non-return valve and the
mixing chamber has to be relatively long, resulting in a
relatively large space filled with the dilute mixture.
Another difficulty is that the non-return valves result in
considerable pressure losses in the flow system, making it
necessary to use more powerful and thus more expensive
pumps.
An object of the present invention is to solve the
indicated problems in a simple manner, to reduce the danger
of hygienic contamination and impairment of taste, if
possible, without the need for more expensive pumps.
This invention provides a water-jet injection device in
dispensers for producing and dispensing mixtures of water
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and another flowable substance or ingredient. The device
includes an injector housing having a mixing chamber which
is between a free outlet end of a water-jet tube inserted
into the injector housing and opening thereinto, and an
intake end of a nozzle section opposite thereto. The
water-jet tube is connectable with a water-supply section
on an intake side, and the mixing chamber is connectable
with a supply container for the another flowable substance
through a valve which opens automatically. The nozzle
section is associated with a section for dispensing the
mixture. The water-supply section is adapted to be
automatically shut off from the mixing chamber by a valve
which is situated directly in the water-jet tube, and is
adjacent the free outlet end of the water-jet tube.
Preferably, the valve situated in the water-jet tube
comprises a valve-closing body adapted to be biased into a
closed position by a magnetic force. Conveniently, the
valve-closing body is a valve-closing ball. Automatic shut
off by the valve occurs when a flow condition of the water
is low, and the valve re-opens when the water starts to
stream in the water supply section. The valve to the
supply container for the another flowable substance can be
opened automatically by action of a water jet entering the
mixing chamber.
In this construction, during intervals between dispensing,
the shut-off between mixing chamber and water supply system
occurs directly in the water-jet tube itself immediately in
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front of the nozzle end of the water-jet tube which freely
projects into the mixing chamber. As a result, the space
left between the shut-off point and the mixing chamber
inside the water supply system is small, thus substantially
eliminating contamination and hygienic problems which
otherwise occur.
The non-round flow cross-section offers little resistance
to flow. In order to further reduce the flow resistances
in spite of the shut-off device, the flow portion can have
a radially-profiled flow cross-section between the valve
seat and the inlet of the discharge nozzle. With an open
non-return valve this enables a relatively large flow
cross-section to be kept free, so that flow resistance is
low and normal, and less expensive pumps can be used.
Hereinafter, the invention is described in detail with
respect to an embodiment which is shown in the accompanying
diagrammatic drawings, in which:
Fig. 1 is a longitudinal section of a known dispenser
having a water-jet injection device of conventional
construction; and
Fig. 2 is a larger cross-section through the water-jet tube
according to the invention on an enlarged scale,
incorporated in the injector housing of a water-jet
injection device.
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For better understanding of the invention, the possible use
of a water-jet tube according to the invention is shown in
Fig. 1.
The illustrated water-jet injection device comprises a
casing 2 for connection to an elongate nozzle on a water
supply section 1. A water-jet tube 3 is inserted firmly
and in a sealing-tight manner in the nozzle, and its outlet
end projects freely into a mixing chamber 8 in the injector
casing. The free end of the water-jet tube is opposite the
inlet end of a nozzle and diffusion section 4, which merges
into a portion for delivery of the mixture. The mixing
chamber 8 is also connected by a nozzle to a storage vessel
6 for the freely-flowing substance to be mixed with the
water from the water-jet tube. A valve 7 is tightly
inserted in the connecting region and is constructed so
that, under the action of the water jet entering the mixing
chamber 8, the valve automatically opens and allows the
freely-flowing substance to flow from the storage vessel 6
into the mixing chamber 8, where the substance is mixed
with water and discharged as a mixture through the nozzle
and diffusion section into the delivery portion.
At the end of a dispensing operation, some of the mixture
remains in the mixing chamber 8 and in the other parts of
the injection device. This part of the mixture can diffuse
through the water-jet tube 3 back into the water supply
system 1, resulting in contamination and hygienic problems,
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and also with a possibly adverse effect on the taste of the
next mixture to be dispensed.
To avoid these disadvantages, in the embodiment according
to the invention in Fig. 2, a non-return valve is inserted
in the water-jet tube 9. As in the known embodiment of
Fig. 1, the water-jet tube is firmly and tightly inserted
in the water supply nozzle of the injector casing 11, so
that the delivery end 12 projects freely into the mixing
chamber 13 of the injector casing. The arrow 10 shows the
direction of flow of water from the water supply section,
the arrow 14 shows entry into the nozzle and diffusion
section (not shown), and the arrow 15 shows entry through
the inlet valve (not shown) of the substance from the
storage vessel (also not shown).
The free end of the water-jet tube is in the form of a
discharge nozzle, having an inlet end 12a for water. A
valve seat 18a for a valve-closing ball 17 is provided
directly in front of the inlet end 12a of the
aforementioned nozzle portion. The valve-closing ball is
made of non-rusting stainless but magnetisable material.
The valve seat 18a is made of permanently magnetic
material, on the end pointing in the direction of flow, of
a sleeve-like flow member 18 inserted directly into the
water-jet tube. The flow member can be coated with a
suitable material for preservation of food. The permanent
magnet 18 is fitted in the water-jet tube, e.g. by means of
a threaded sleeve 22, so as to be sealing-tight and
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axially-immovable, using sealing rings 20, 21 and a sealing
sleeve 19.
A flow section 16 is disposed between the valve seat 18a
and the inlet 12a of the nozzle end of the water-jet tube
12. The flow section has a profiled cross-section, and
comprises an abutment 16a which limits the travel of the
ball 17 when the valve is opened by the flow of incoming
water. The flow section 16 can be formed inside the actual
water-jet tube, or on a flow member insertable into the
water-jet tube. The flow member can, for example, comprise
three peripherally-distributed radial ribs and an annular
member, resulting in a substantially star-shaped flow
cross-section. The path along which the valve-closing ball
17 moves, ending at the abutment 16a, is provided in the
flow member.
As can be seen, the space which the mixture can enter in
the water-jet tube, between its free end and the valve seat
18a, is very small. Consequently, the mixture is only
slightly diluted. This substantially alleviates hygienic
problems and the risk of affecting the taste of the
mixture. This small space is reliably cleaned by the high
speed of the water whenever a flow occurs through the jet
tube. The pressure losses are extremely small since, when
the valve is open, the prestress on the ball by the
magnetic force is small in the direction towards the valve
seat and just sufficient to move the valve-closing ball
back in the direction towards the valve seat when the water
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supply is terminated. When the valve is closed, however,
the closing force is quite strong, since in this position
of the ball 17 the magnetic gap is small and the ball is
therefore held in the closed position by a strong magnetic
force. Owing to the very small prestress in the open
position, the flow resistance also is low after initial
opening of the valve. The flow resistance can be kept
particularly low by profiling in the region of the flow
cross-sections 16. Initially the valve can be reliably
opened by impact of water, by suitably designing the water
supply.
The arrangement is very simple and economic, and has a
reliable self-cleaning effect along the entire length of
the water-jet tube.
Due to the motion of the valve-closing ball 17 toward the
valve seat, the arrangement also can be used as a drip
barrier preventing dripping at the end of the dispensing
operation.
The jet tube having a non-return valve can, of course, be
used in other metering or dispensing systems and in
injection devices constructed differently from that
specifically illustrated in Fig. 1.
