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BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to a method of continuously producing a
flowable mixture, composed of at least two components, which components
are separately fed from a respective storage tank and thereafter
intermixed to produce a final product.
The invention also relates to an apparatus for the continuous production of
a flowable mixture, composed of at least two components, which components
are separately fed from a respective storage tank, and thereafter
intermixed to produce a final product.
2. DESCRIPTION OF THE PRIOR ART
The commonly applied procedure for producing such flowable mixtures is to
feed the individual components, which are to make up such mixture, which
are generally in a liquid state, out of their respective storage or
keeping, respectively, tanks, whereafter these flowing components are
dosed by individually controlling the respective mass flows of the
components being fed, and by keeping the individual mass flows at a
constant value. To this end, use is made of pumping devices, flowmeters,
controlling apparatuses, etc., which form together a control circuit.
It is generally known that a certain time span elapses until such a control
circuit has stabilized, i.e. until it has reached its steady-state
condition. Depending from the complexity of a given control circuit, the
mentioned time span is of a more or less long duration.
The product, which is composed of the various components, does generally
not feature the desired quality during the duration of mentioned time span
and accordingly must be led off as waste, which is obviously a more or
less big loss for a respective production plant.
SUMMARY OF THE INVENTION
It is, therefore, a general object of the present invention to provide a
method of continuously producing a flowable mixture, composed of at least
two components, which produces no waste.
A further object of the invention is to provide an apparatus for the
continuous production of a flowable mixture, composed of at least two
components that are intermixed to produce a final product, which does not
give rise to the production of waste.
A further object is to provide a method of continuously producing a
flowable mixture, composed of at least two components, comprising the
steps of measuring the actual value of the mass flow of each separate
component fed from its respective storage tank, and of comparing said
actual value with a respective rated value; of feeding all components fed
from their respective storage tank in a closed loop back to their
respective storage tank until the actual value of every single mass flow
corresponds to its rated value; and of bringing the individual components
together and intermixing same as soon as each actual value corresponds to
its respective rated value.
Yet a further object of the present invention is to provide an apparatus
for the continuous production of a flowable mixture, composed of at least
two components, which apparatus comprises a plurality of storage tanks, of
which each is intended to store one of the components to be intermixed,
each storage tank is followed in the direction of the flow of the
component by a component conveying apparatus, a flowmeter coupled to a
component flow controller and a switch-over valve, which switch-over valve
is coupled on the one hand to a return line extending back to the
respective storage tank, and on the other hand to a feed line extending to
a common component mixing apparatus, and comprising a means for
controlling the mass flow of the respective component.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be better understood and objects other than
those set forth above will become apparent when consideration is given to
the following detailed description thereof. Such description makes
reference to the annexed drawings, wherein:
FIG. 1 illustrates a production program of known plants;
FIG. 2 illustrates a production diagram of a plant operated in accordance
with the present inventive method; and
FIG. 3 illustrates a flow diagram of an apparatus structured in accordance
with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates the production diagram, arrived at by known procedures.
The letter M designates the mass flow and T denotes the time. The object
of the operation is now to arrive at the rated value and to maintain the
rated value in a steady state. The plant is started at the point O, from
which point O the mass flow begins to increase and shall finally reach its
rated value, i.e. it is to reach the condition in which the actual value
corresponds to the rated value (obviously within the allowed tolerances).
A certain time span v elapses before the sought steady-state condition is
arrived at. According to the procedure followed in known plants, i.e. in
accordance with known methods, the individual component flows are brought
together already during this time span v, which components are also mixed,
and quite obviously the product produced thereby does not feature the
desired or rated, respectively, composition. Such product now cannot be
used, i.e. in case of e.g. a foodstuffs plant or a semi-luxury products
plant, the mixture obtained thereby cannot be filled into a container, a
can or bottle, respectively. Contrary thereto, the mixture which does not
feature the necessary quality must be led away as waste.
Attention is now drawn to FIGS. 2 and 3. FIG. 3 illustrates schematically,
roughly in the form of a flow sheet, a plant in which four components are
intermixed such to produce a mixture. The reference numerals 1-4 denote
each a storage tank for one individual component. It shall be assumed that
storage tank 1 contains a sugar solution, storage tank 2 a first
concentrate, storage tank 3 a second concentrate and storage tank 4
contains water. The commodity present in storage tank 1 flows through the
outflow line 21 to a conveying apparatus 5. It has been indicated above
that as example a sugar solution is contained in the storage tank 1.
Correspondingly, the conveying apparatus 5 comprises a fluid flow engine
or centrifugal pump, respectively. The amount of the commodity pumped by
this conveying apparatus 5 flows thereafter through a flowmeter 10, which
measures the mass flow. This flowmeter 10 is connected to a controller 9,
which in turn controls a control valve 15, by means of which the mass flow
of the commodity flowing out of the storage tank 1 and being conveyed by
the pump 5 is controlled, with the object to control the actual value
detected at the flowmeter 10 via the controller 9 such that it reaches its
rated value.
A switch-over valve 11 is located, seen in the direction of flow after the
control valve 15. This switch-over valve 11 can be operated in two
positions. In its first control position it generates a fluid flow
connection between the outflow line 21 after the control valve 15 and a
return line 12 through which return line 12 the commodity can flow back
into its storage tank 1.
If the switch-over valve 11 is in its second position, the commodity flows
through the feed line 14 to a static mixer 13.
The outflow coming from the storage tanks 2-4 is conveyed and specifically
controlled by the same procedure. However, in this case it is assumed that
the concentrates, stored in the storage tanks 2 and 3, are highly viscid
materials such that the conveying apparatus located at the storage tank 2
is a positive displacement pump 6, and the conveying apparatus located at
the storage tank 3 comprises a positive displacement pump 7. These pumps
6, 7 may be, for instance, geared pumps. Conclusively, the mass flow
detected at the flowmeter 10 is controlled by the respective controller 9,
in that this controller 9 influences the speed control device of the gear
pump 6, 7, which control device is schematically identified by the
reference numeral 16.
All three outflow lines 21 of these storage tanks are also provided with a
switch-over valve 11, by means of which the commodity that is being
conveyed is controlled to either flow through the return line 12 to its
respective storage tank or then to the feed line 14, which feed line 14 is
connected to a mixer 13, which in the illustrated embodiment is a static
mixer. This static mixer 13 is connected to an outflow line 17, provided
with further measuring or detecting, respectively, devices, which are
illustrated on an exemplary basis only by the reference numerals 18, 19
and 20. The outflow line 17 extends finally, for instance, to a racking
apparatus, eg to a bottling apparatus.
During the initial start-up phase of the plant, the switch-over valves 11
are operated in such a position according to which the commodities flowing
out of the respective storage tanks 1-4 are led back through the return
lines 12 into said storage tanks. This state of return flow will now be
maintained for every component until the individual control circuit, i.e.
the four control circuits of this embodiment have stabilized and the
actual values as determined by the flowmeters 10 correspond to the
corresponding rated values (within the tolerable limits), corresponding to
the respective final product. After all four control circuits have
stabilized, all four switch-over valves 11 are switched, such that now the
components flow through the feed line 14 to the mixer 13. It is important
to note that the condition for the mentioned switching over is that all
four control circuits have reached a steady state. In other words, if in
case of a high viscid concentrate fed from the storage tank 2 a time span
of longer duration is needed until its control circuit arrives at its
steady state condition than of the other three components, these other
components, although their control circuit has already arrived at its
steady state condition, will still be fed back through their return lines
12 into their storage tank, and only after the last and final control
circuit has reached its steady state condition, the switching over of all
four switch-over valves 11 is carried out.
It is to be noted that the switching over procedure of the switch-over
valves 11 can in no way influence and disturb the stability of the control
circuits because all corresponding components, i.e. pumps, flowmeters,
control valves, controllers, etc., which together form the respective
control circuits, are no longer influenced by this switching operation
because merely the direction of flow is altered. This switching is,
therefore, not detected as a disturbance in the control circuit, and the
component values of the individual components, which together will form
the final product, features immediately the desired rated values.
The individual components flow at the now exactly controlled mass flow
through the feed line 14 to the mixer 13, which in this embodiment is a
static mixer and can be structured in accordance with various generally
known designs, in accordance with the final product which the components
are being mixed.
After the mixer various properties, parameters of the product, are
measured, indicated and also registered by detecting devices 18, 19 and
20. These detecting devices will be explained somewhat more in detail
further below.
As soon as the control circuits have reached their stable, steady state
condition, i.e. when the individual components are fed through the feed
line 14 to the static mixer 13, anyone of the flowmeters 10 detects a not
tolerable deviation of the rated value, all switch-over valves 11 get
again switched to make the communication with the return line, such that
all components, i.e. also those components flowing with a mass flow which
corresponds to the rated flow, are again fed back in a closed loop to the
storage tanks 1-4. This state is now maintained until the single control
circuit, in which a deviation has been detected, has again reached its
rated value. Thereafter the switching of the switch-over valve is
initiated and all components led again to the mixer 13 for the final
production.
The detecting devices 18, 19, 20 detect whether the final product prior to
for instance the bottling features truly the characteristics of the
specific product being marketed (for example concentration, pH-value,
acidity, viscosity, contents of acidity and sugar, alcohol, etc.).
Accordingly, a controlling or checking, respectively, of the produced
mixed product is made. As example it can be mentioned that the detecting
device 18 determines the density, the detecting device 19 the acidity and
the detecting device 20 the concentration of the mixture. If now one of
the detecting devices 18-20 detects a deviation from the rated value, the
switch-over valves 11 are again switched to the return flow state
(although the individual mass flows according to the flow meters 10
correspond to the rated values). At the same time, an alarm is produced,
such that an operator can check the entire plant regarding any defects. A
variety of reasons may give rise for such a defect case, for instance a
wrong recipe for the beverage, a wrong selection of the individual
components or it is also possible that defects have occurred at measuring
or detecting devices. By the above after-checking, it is accordingly not
possible that the final product does not correspond to the given features
or characteristics. If now the method forming the basis of the
illustration of FIG. 3, whereto also reference is made to FIG. 2, is
compared with known methods, the following important advantage can be
seen.
According to the diagram of FIG. 1, the respective mixture is led away as
waste, i.e. as loss of the production during the time span v until all
control circuits have stabilized, are in their steady-state condition.
According to FIG. 2 now, these mass flows of the individual components are
not led away as waste during the same time span v and rather led back via
the bypass, the return line 12, to their individual storage tanks, such
that no loss will be suffered at all. It should be borne in mind that the
outflow line 17 after the mixer 13 of any production plant extends to
racking apparatuses, for instance to bottling apparatuses. Quite
obviously, time and again, disturbances or any kind of interruption of the
operation can happen in such apparatus, such that the complete mixing
plant must be switched over to a "non-load" condition. If now a respective
disturbance, i.e. the reason therefor, has been eliminated, the entire
plant must again be started up, i.e. it must be put back into operation,
whereby the above mentioned losses occur in plants operating in accordance
with the known methods, and in contrast thereto, the plant operating in
accordance with the present invention, does not produce any loss of any of
the components. Interruption of the production can occur at the racking
stations several times during one working day, and such must not actually
be some kind of break-down or malfunctioning of the apparatus, the reason
for such disturbance may for instance simply be that the feeding of the
bottles is interrupted for a short time span, because for instance any
kind of delivery of the bottles can suffer a short delay or interstice,
because the feeding of any other kind of article may suffer a short
interruption, for instance labels, because the bottle cleansing and
rinsing plant may cause a short interruption, ect.
Because now the procedure in accordance with the illustrated embodiment is
such that on the one hand the respective mass flow of the individual
components is measured and the mixing is commenced not earlier than when
all actual values correspond to the rated values, and on the other hand
the mixture is analyzed once more, and also if during this step an actual
value does not correspond to a rated value, a switching over to the
returning operation (return line 12) is made, no loss of production
whatsoever is suffered, and accordingly a large yield of the production is
attained. Furthermore, the plant structured in accordance with the
inventive method can be operated simply and quite obviously an extremely
high quality standard of the final product is reached.
While there are shown and described present preferred embodiments of the
invention, it is to be distinctly understood that the invention is not
limited thereto, but may be otherwise variously embodied and practiced
within the scope of the following claims.
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