Method and Device for Controlling the Production of an Extract Using a Solid-Liquid Extraction Process

Abstract

Controlling the production of an extract using solid-liquid extraction that improves the exchange of material during the extraction process and allows a controlled dehumidification of a raffinate with residual moisture in order to obtain additional valuable extract is described. The steps include providing a first mass in an extraction container, supplying a second mass to the first mass without spatial constraints and distributing and mixing the second mass into and with the first mass, discharging a mixture of the extract and the raffinate from the extraction container, separating the discharged mixture into the raffinate with residual moisture and extracts released from the raffinate with residual moisture, and further treating the raffinate with residual moisture at least such that the residual moisture consisting of the extract is at least partly removed from the raffinate with residual moisture by dehumidification and is supplied to the already separated extract.

Claims

1. A method to control the production of an extract by means of solid-liquid extraction by means of an extraction container in which a secondary solvent with a first mass and a primary mixture consisting of a solid primary solvent and a transition component with a second mass are brought into contact with each other for a predetermined dwell time to obtain the extract, and in which the obtained extract and a complementary portion of raffinate are separated from each other after the dwell time, the method comprising: (i) providing the first mass in the extraction container; (ii) supplying the second mass to the first mass without spatial constraints and distributing and mixing the second mass into and with the first mass; (iii) discharging a mixture consisting of the extract and the raffinate from the extraction container; (iv) separating the mixture discharged according to step (iii) into the raffinate with residual moisture and an extract released from the raffinate with residual moisture; (v) further treatment of the raffinate with residual moisture at least such that the residual moisture consisting of the extract is at least partly removed from the raffinate with residual moisture by dehumidification and is supplied to the already separated extract; (vi) dehumidifying the raffinate with residual moisture to a tolerable portion of extract in the raffinate with residual moisture by supplying mechanical energy to the raffinate with residual moisture; (vii) determining a first mass flow of the mixture discharged according to step (iii), and a second mass flow of the extract freed from raffinate with residual moisture obtained according to steps (iv) and (v), in each case over a span of time; (viii) determining the degree of dehumidification by comparing the first mass flow with the second mass flow, wherein the mass difference resulting therefrom in the time span before and after humidification is compared with a mass difference arising with complete dehumidification that corresponds to the mass of the primary solvent before extraction within the relevant time span; and (ix) controlling the degree of dehumidification carried out according to steps (v) and (vi) by feedback control intervention to the first mass flow and the supply of mechanical energy.

2. The method according to claim 1, wherein: the second mass is not added completely but rather in portions and continuously to the secondary solvent.

3. (canceled)

4. The method according to claim 1, comprising: (x) controlling the first mass flow {dot over (m)}.sub.1) depending on the raffinate with residual moisture such that, when the tolerable portion is exceeded, at least one of: a) the first mass flow {dot over (m)}.sub.1) is reduced while the supply of mechanical energy remains the same, or b) the supply of mechanical energy is increased while the first mass flow {dot over (m)}.sub.1) remains the same, or c) the first mass flow {dot over (m)}.sub.1) is reduced, and the supply of mechanical energy is simultaneously increased until the tolerable portion rises.

5. The method according to claim 1, wherein: the tolerable portion established in step (vi) correlates with other control parameters that are determined with the following method steps: (xi) determining a first differential mass of the raffinate with residual moisture from the first and second mass {dot over (m)}.sub.1, {dot over (m)}.sub.2) flows determined according to step (vii) according to the following balance equation:
Δm(A.sup.+)=({dot over (m)}.sub.1−{dot over (m)}.sub.2)Δt; (xii) determining a second differential mass m(A∞B)) of the primary mixture from the first mass flow {dot over (m)}.sub.1) determined according to step (vi) according to the following relationship:
Δm(A∞B)={dot over (m)}.sub.1Δtk, wherein a concentration results with $\begin{array}{cc}k=\frac{m}{M+m}=\frac{m\left(A\infty B\right)}{M\left(C\right)+m\left(A\infty B\right)}=\frac{m\left(A\infty B\right)}{\left(M+m\right)\left(\left(C\infty B\right)+A\right)};& \end{array}$ and (xiii) determining a tolerable first differential mass of the raffinate with residual moisture according to the first differential mass (Δm(A.sup.+)) determined according to step (xi), and the second differential mass m(A∞B)) determined according to step (xii) according to the following definitional determination for the tolerable portion: $\delta =\frac{\Delta {m\left(A^{+}\right)}_{tol}-\Delta m\left(A\infty B\right)}{\Delta m\left(A^{+}\right)-\Delta m\left(A\infty B\right)}.$ wherein: δ is the tolerable portion, Δm(A.sup.+) is the first differential mass of the raffinate with residual moisture A.sup.+, {dot over (m)}.sub.1 is the first mass flow, {dot over (m)}.sub.2 is the second mass flow, Δt is the span of time, Δm(A∞B) is the second differential mass of the primary mixture A∞B consisting of the solid primary solvent A and the transition component B, k is the concentration, M is the first mass of the secondary solvent C, m is the second mass of the primary mixture A∞B, C∞B is the extract, and Δm(A.sup.+).sub.tol is a tolerable first differential mass of the raffinate with residual moisture A.sup.+.

6. The method according to claim 1, wherein: the dehumidification of the raffinate with residual moisture performed with step (v) is performed at the same time as or after the separation of the mixture performed with step (iv).

7. The method according to claim 1, wherein: all the obtained extract freed from raffinate with residual moisture is subject to filtration to segregate undesirable fine and very fine particles.

8. The method according to claim 1, wherein: all the obtained extract freed from raffinate with residual moisture is subject to separation in a centrifugal field for pre-clarification and thereby becomes a pre-clarified extract.

9. The method according to claim 1, wherein: the mixture discharged according to step (iii) is discharged solely under the effect of gravity.

10. The method according to claim 9, wherein: the discharging of the mixture is additionally supported by applying a gas pressure from a gaseous propellant to a free surface of the mixture.

11. The method according to claim 1, wherein: the part of the method defined by steps (i) and (ii) is carried out at least in a first extraction container that differs from a second or a third extraction container, and that is designed as a discontinuously working homogeneous reaction container, wherein to ensure a desired mass ratio of the second mass to the first mass, the second mass is supplied completely to the first mass.

12. The method according to claim 1, wherein: the part of the method defined by steps (i) and (ii) is carried out at least in a first extraction container that differs from a first or a third extraction container, and that is designed as a discontinuously working homogeneous reaction container, wherein the second mass is divided into a finite number of second partial masses, and in so doing into at least two second partial masses, and the second partial masses are each supplied separate from each other to corresponding first partial masses of the first mass to ensure a desired mass ratio of the second mass to the first mass.

13. The method according to claim 1, wherein: the part of the method defined by steps (i) and (ii) is performed at least in a third extraction container that differs from a first or a second extraction container, wherein the first mass added according to step (i) is discharged during the dwell time in the form of a plug flow oriented in the direction of gravity, a forcibly generated mass flow of the first mass is continuously added to a mass flow of the second mass such that a desired mass ratio of the second mass to the first mass is ensured in the discharged mixture, the continuously discharged mixture is supplied from above to a free surface of a mixture located in the third extraction container, supplying the second mass to the first mass ends when the mixture first supplied to the third extraction container has flowed as a mixture from top to bottom through the third extraction container in the form of the plug flow after expiration of the dwell time, and the method is continued according to steps (iii) to (ix).

14. (canceled)

15. A device for controlling the production of an extract by means of solid-liquid extraction using an extraction container, wherein: the extraction container has at least one first inner region that, in a top region, possesses a first supply connection for supplying a primary mixture, and, in a bottom region, a drainage connection for drainage of a mixture consisting of an extract and a raffinate, in a top region, the extraction container possesses a second supply connection for supplying a secondary solvent, the drainage connection discharges into a drain line, the drain line has, viewed in a direction of flow and at a vertical distance from the drainage connection by a supply height relative to the direction of gravity, a control valve, a first mass flow meter for determining a first mass flow {dot over (m)}.sub.1 for the mixture, a separating device for separating the mixture into the extract and a raffinate with residual moisture, a dehumidification apparatus for dehumidifying the raffinate with residual moisture, and a second mass flow meter for determining a second mass flow {dot over (m)}.sub.2 for an extract free from raffinate with residual moisture, the separating device and the dehumidification apparatus are realized in the form of a controllable vibration or shaking sieve, and a control apparatus is provided that, in terms of signaling, is at least connected to the control valve, the first and the second mass flow meters, and the vibration or shaking sieve, and that controls the degree of dehumidification by a feedback control intervention in the first mass flow and the supply of mechanical energy.

16. (canceled)

17. The device according to claim 15, wherein: viewed in the direction of flow, a filter apparatus is arranged after the second mass flow meter in the drain line.

18. The device according to claim 17, wherein: viewed in the direction of flow, the filter apparatus is upstream from a centrifugal separator.

19. The device according to claim 15, wherein: at least one first extraction container is designed as a discontinuously working homogeneous reaction container that, in the top region of a single first inner region has a single first supply connection, and, in the bottom region of the first inner region has a single drainage connection, and the first extraction container possesses the supply connection in the top region.

20. The device according to claim 15, wherein: at least one second extraction container is designed as a discontinuously working homogeneous reaction container that has at least one second inner region above the first inner region and directly adjacent thereto, a number of inner regions is provided, and each additional inner region is arranged above the preceding inner region and directly adjacent thereto, each inner region provided above the first inner region is assigned another first supply connection for the primary mixture, each additional first supply connection is assigned another drainage connection below and at a distance therefrom, such that the mixture obtained in the respective assigned inner region is discharged as unadulterated as possible from the primary mixture that flows to the adjacent inner region below via the assigned first supply connection, and the second extraction container possesses the supply connection in the top region.

21. The device according to claim 15, wherein: the first supply connection and each other first supply connection are each connected to a product-friendly rotating delivery apparatus.

22. A device for producing an extract by means of solid-liquid extraction by means of a third extraction container from which a circulation line branching off a drain line runs, wherein: the third extraction container: has a supply line for supplying a secondary solvent or a mixture consisting of a primary mixture and the secondary solvent, and the supply line enters via a third foot area into the third extraction container, penetrates the third extraction container up to a third headspace, and discharges at the third headspace via an outlet, and has a drainage connection for discharging the secondary solvent or a mixture consisting of an extract and a raffinate, and the drainage connection leaves the third foot area and transitions there into the drain line, the drain line has, viewed in a direction of flow and at a vertical distance from the drainage connection by a supply height in the direction of gravity: a control valve, a first mass flow meter for determining a first mass flow {dot over (m)}.sub.1 for the mixture, a separating device for separating the mixture into the extract and a raffinate with residual moisture, a dehumidification apparatus for dehumidifying the raffinate with residual moisture, and a second mass flow meter for determining a second mass flow {dot over (m)}.sub.2 for an extract free from raffinate with residual moisture, wherein the separating device and the dehumidification apparatus are realized in the form of a controllable vibration or shaking sieve, from the drain line, upstream from the control valve: the circulating line branches at a branching point and joins the supply line at a joining point, and is flowed through from the branching point to the joining point, and inside the circulating line, relative to the branching point, first a pump for conveying the secondary solvent and then a dosing apparatus for dosing primary mixture into the secondary solvent are provided, and a control apparatus is provided that, in terms of signaling, is at least connected to the control valve, the first and the second mass flow meters, and the vibration or shaking sieve, and that controls the degree of dehumidification by a feedback control intervention in the first mass flow and the supply of mechanical energy.

23. The device according to claim 22, wherein: at least two third stirring apparatuses are provided in a liquid-impacted outer region of the third headspace arranged over an outer region and, due to their particular installation position, are able to generate a flow movement directed toward the center of the third extraction container with a flow component oriented in the direction of gravity.

24. The device according to claim 22, wherein: the drainage connection is arranged centrally and at a bottom end of the third extraction container, and the supply line is guided concentrically through the drainage connection.

25. The device according to claim 22, wherein: the dosing apparatus is connected to a rotating displacement pump.

26. The device according to claim 15, wherein: the extraction container has a supply connection for supplying a compressed gas in the region of a top end of the extraction container.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The invention is represented in more detail by the following description and the appended figures of the drawing and the claims. The invention can be realized in a wide range of embodiments of a method for controlling the production of an extract by means of solid-liquid extraction of the generic type and by means of respective three differently designed extraction containers. Moreover, the invention is realized in a very wide range of embodiments of a device for performing the aforementioned particular method. In the following, the method and the device will be described with reference to the drawing, in connection with one of the three extraction containers and illustrated by the preferred exemplary embodiment for controlling the production of a tea extract.

[0073] FIG. 1 shows a schematic representation of a first device with a first extraction container.

[0074] FIG. 2 shows a schematic representation of a second device with a second extraction container.

[0075] FIG. 3 shows a schematic representation of a third device with a third extraction container, and

[0076] FIG. 4 shows a flow chart of the method that is carried out with each of the devices according to FIGS. 1-3.

DETAILED DESCRIPTION

[0077] General

[0078] Initially a few basic notes are offered in advance to help understand the following symbols for illustrating solid-liquid extraction, or respectively solid-liquid hot extraction (with regard to the following and also preceding notation: 1. terms for the generic case comes first; and 2. [production of tea concentrate] comes second).

[0079] A solid-liquid extraction exists for example when tea concentrate is extracted from tea leaves with the assistance of water. Extraction is therefore not complete decomposition, because only one of the components to be separated is in an approximately pure state; the others are only relocated and are present in a mixture after the extraction.

[0080] The following notation used at a few places, such as: [0081] m(A∞B ) is to be understood as m=f((A∞B)); and [0082] (M+m)((C∞B)+A) is to be understood as (M+m)=f((C∞B)+A) (analogous to the mathematical notation of y=f(x), or respectively y(x)).

[0083] A feed mixture (A∞B) is termed “primary mixture” [tea leaves], and a solution generated by extraction is termed “secondary mixture” or extract (C∞B) [tea concentrate], wherein the notation (A∞B), or respectively (C∞B), designates the phase “mixture”, or respectively “solution”. A substance transitioning from one phase to the other is termed a “transition component” [theine and other desirable or undesirable accompanying substances] that in the following will be identified as B. A non-transitioning component of the primary mixture is a “primary solvent” or a carrier material A [carrier material before extraction]. After extraction, it occurs in a nearly pure state as a “raffinate” [extracted tea leaves] whereas the extract (C∞B) [tea concentrate] is composed of a secondary solvent C [water; hot extraction: hot water or boiling water.fwdarw.reduced hereinafter to hot water] and the transition component B [theine and other desirable or undesirable accompanying substances]. The above solid-liquid extraction or solid-liquid hot extraction can be depicted as follows using the above symbols by the following scheme (1) (see also FIGS. 1 to 4):

(A∞B)+C.fwdarw.(C∞B)+A   (1)

wherein the term (A∞B)+C will hereinafter be termed a mixture (of the primary mixture and secondary solvent) [mixture (of tea leaves and hot water)], and the term (C∞B)+A will hereinafter be termed a mixture (of extract+raffinate after extraction) [tea concentrate+extracted tea leaves].

[0084] First Device (FIG. 1)

[0085] A first device 1 for controlling the production of an extract by means of solid-liquid extraction, in particular solid-liquid hot extraction, by means of a first extraction container 10 according to the invention is shown in FIG. 1.

[0086] The first extraction container 10 has a single and first inner region Ib1 that, in a top region, a first headspace 10.1, possesses a single supply connection 11 with a supply valve 11a for supplying a secondary solvent C, which is provided with a predetermined first mass M in a first inner region Ib1 where the first inner region Ib1 forms a free surface N. Moreover, a first supply connection 12 with a first supply valve 12a is provided in the first headspace 10.1 for supplying a primary mixture (A∞B) [tea leaves], which is added with a predetermined second mass m of the first mass M to a corresponding mixture (A∞B)+C [mixture of tea leaves and hot water]. A first foot area 10.2 of the first extraction container 10 has a single drainage connection 14 with a drain valve 14a for completely discharging a mixture (C∞B)+A consisting of an extract (C∞B) and a raffinate A. Moreover, at the top end of the first headspace 10.1, a supply connection 13 with a supply valve 13a is provided for supplying a gas propellant, a compressed gas G, with a gas pressure p.

[0087] The first extraction container 10 possesses insulation D for thermal insulation against its environment, and a first stirring apparatus 10a that ensures an as homogeneous as possible, but always product-friendly even distribution of the substrate located therein in the discontinuously working homogeneous reaction container. The first supply connection 12 is connected to a product-friendly, preferably rotating delivery apparatus 22. The delivery apparatus 22 preferably has a screw conveyor 22a driven by a drive motor M.sub.A, preferably a controllable drive motor 22b. The primary mixture (A∞B) is kept in a storage tank 22c from which the primary mixture (A∞B) runs to the screw conveyor 22a.

[0088] The drainage connection 14 discharges into a drain line 15 that, viewed in the direction of flow, has a control valve 16 at a vertical distance from the drainage connection 14 by a supply height H in the direction of gravity. The drain line 15 moreover accommodates a first mass flow meter 17, again viewed in the direction of flow, for determining a first mass flow {dot over (m)}.sub.1 for the mixture, a separating device 18 with a suitable sieve 18a, and a raffinate collecting container 18b for separating the mixture (C∞B)+A into a raffinate with residual moisture A.sup.+ [extracted tea leaves with residual moisture] and an extract (C∞B)** [tea concentrate freed from extracted tea leaves with residual moisture], freed from raffinate with residual moisture A.sup.+, a dehumidification apparatus 19 for dehumidifying the raffinate with residual moisture A.sup.+, and a second mass flow meter 20 for determining a second mass flow {dot over (m)}.sub.2 for the extract (C∞B)** freed from residual moisture A.sup.+.

[0089] The separating and dehumidifying apparatus 18, 19 (hereinafter also just sieve 18, 19) can be realized by two separate assemblies or by a single assembly, preferably by a vibrating or shaking sieve 18, 19. When the design is integrated, the sieve 18a is supplied mechanical energy ME by means of a drive motor (M.sub.A), preferably a controllable vibration or shaking drive 19a.

[0090] The dwell time of the raffinate with residual moisture A.sup.+ can be influenced by the angle of the sieve 18, 19, whereby its residual moisture content in turn can be controlled. A greater sieve angle shortens the dwell time and increases the residual moisture content; a lesser sieve angle influences these quantities in reverse. The sieve geometry also has an influence on the throughput of the mixture after extraction. The width of the sieve 18, 19 is determined by the required throughput. An expansion of the sieve width when there is an elevated throughput is necessary to ensure a sufficient distribution of the solid particles on the sieve surface. Lengthening the sieve 18, 19 increases the dwell time of the solid material on the sieve 18, 19 and means a further dehumidification of the raffinate with residual moisture A.sup.+ due to a longer treatment. The method according to the invention can therefore be modified inter alia by a modified supply volume of the mixture to the sieve 18, 19, by the angle of the sieve 18, 19, as well as by a change in the sieve geometry.

[0091] A control apparatus 21 is provided that is connected in terms of signaling via signal transmission lines 21a at least to the control valve 16, the first and the second mass flow meter 17, 20 and the dehumidifying apparatus 19 (signal connections e to h). The valves 11 to 14 are actuated in automatic mode by the control apparatus 21 via signal connections a to d.

[0092] Downstream from the second mass flow meter 20 viewed in the direction of flow a filter device 24 is arranged in the drain line 15 for segregating fine and very fine particles from a pre-clarified extract (C∞B)*, wherein the pre-clarified extract (C∞B)* becomes the filtered extract (C∞B) through the filter apparatus 24.

[0093] For preliminary clarification of the extract (C∞B)** freed from raffinate with residual moisture A.sup.+, a centrifugal separator 23 for segregating coarser particles P that have passed through the sieve 18a of the separating apparatus 18 while segregating the raffinate with residual moisture A.sup.+ is optionally upstream from the filter apparatus 24, also viewed in the direction of flow. By the centrifugal separator 23, the extract (C∞B)** freed from raffinate with residual moisture A.sup.+ becomes the pre-clarified extract (C∞B)*, which has the effect of extending the service life of the filter apparatus 24.

[0094] Additional first extraction containers 10′ 10″ of the above-described type can be connected to the drain line 15 between the drain valve 14a and control valve 16 to increase the production output of the first device 1.

[0095] First Method (FIGS. 1 and 4)

[0096] Just like the second and third methods (FIGS. 2 and 3), the first method is characterized by method steps (i) to (ix) and, in an advantageous embodiment, by method steps (x) to (xiii), which are graphically illustrated in terms of their influential relationship and importance in a flowchart in FIG. 4. The second and the third methods differ from the first method which is carried out using the first extraction container 10 in terms of the treatment of the substrate in the assigned second, or respectively third extraction containers 100, 1000 and the related procedural measures until the mixture is discharged according to step (iii) of the method. The following description of the method is restricted to the terminology for producing tea concentrate as indicated in the list of reference signs for the employed abbreviations in the concordance of superordinate terms.

[0097] According to step (i), the first mass M [hot water C] is provided in the first extraction container 10 via the supply connection 11 (FIG. 4: provision of C and M, .fwdarw.M(C); FIG. 1).

[0098] According to step (ii), the predetermined second mass m [tea leaves (A∞B)] is added to the provided first mass M without spatial constraints corresponding to a predetermined concentration k=m/(M+m) via the first supply connection 12, distributed in the first mass M by means of the first stirring apparatus 10a, mixed as homogeneously as possible with the first mass M, and kept in an exchange of substances with each other by extraction for a predetermined dwell time τ [brewing time] (FIG. 4: specification of (A∞B) and m, .fwdarw.m((A∞B)), k and τ; FIG. 1).

[0099] The extraction can be represented by the following scheme (1):

(A∞B)+C.fwdarw.(C∞B)+A   (1)

[0100] The concentration k is defined by equation (4):

[00001]$\begin{array}{cc}k=\frac{m}{M+m}=\frac{m\left(A\infty B\right)}{M\left(C\right)+m\left(A\infty B\right)}=\frac{m\left(\mathrm{A\infty B}\right)}{\left(M+m\right)\left(\left(C\infty B\right)+A\right)}& \left(4\right)\end{array}$

[0101] According to step (iii), after the dwell time τ, the mixture (C∞B)+A [tea concentrate+extracted tea leaves], with the overall mass M+m, consisting of the extract (C∞B) [tea concentrate] and the raffinate A [tea leaves] is discharged from the first extraction container 10 via the drainage connection 14 (FIG. 4: (M+m)((C∞B)+A); FIG. 1).

[0102] According to step (iv), the mixture (C∞B)+A discharged after step (iii) is separated into a raffinate with residual moisture A.sup.+ [extracted tea leaves with residual moisture] and an extract (C∞B)** [tea concentrate freed from extracted tea leaves with residual moisture A.sup.+] freed from raffinate with residual moisture A.sup.+ by means of the separating device 18 (FIG. 4; FIG. 1).

[0103] According to step (v), a further treatment of the raffinate with residual moisture A.sup.+ is at least provided in that the residual moisture consisting of extract is at least partially removed by dehumidification from the raffinate with residual moisture A.sup.+ and supplied to the already segregated extract (C∞B)** freed from raffinate with residual moisture A.sup.+.

[0104] According to step (vi), the raffinate with residual moisture A.sup.+ is dehumidified in the dehumidification device 19, namely to an established, tolerable portion δ of extract (C∞B)** in the raffinate with residual moisture A.sup.+ by supplying mechanical energy (ME) to the raffinate with residual moisture A.sup.+. The extract (C∞B)** additionally obtained thereby is supplied to the extract (C∞B)** freed from raffinate with residual moisture A.sup.+ obtained according to step (iv) (FIG. 4; specification of δ and ME; FIG. 1).

[0105] According to step (vii), the following are determined: the first mass flow {dot over (m)}.sub.1 of the mixture (C∞B)+A discharged according to step (iii) by the mass flow meter 17, and the second mass flow {dot over (m)}.sub.2 of the extract (C∞B)** obtained according to steps (iv) and (v) and freed from raffinate with residual moisture A.sup.+ by the second mass flow meter 20, in each case in a finite time span Δt or an infinitesimal time span dt (FIG. 4: specification of Δt, k; FIG. 1).

[0106] According to definition equation (3)

Δm(A∞B)={dot over (m)}.sub.1Δtk   (3)

a second differential mass Δm(A∞B) of the primary mixture (A∞B) can be determined according to step (xii) with the specification data for Δt, k.

[0107] According to step (viii), the degree of dehumidification is determined by comparing the first mass flow {dot over (m)}.sub.1 with the second mass flow {dot over (m)}.sub.2 (FIG. 4; FIG. 1). According to balance equation (2)

Δm(A.sup.+)=({dot over (m)}.sub.1−{dot over (m)}.sub.2)Δt;   (2)

a first differential mass Δm(A.sup.+) of the raffinate with residual moisture A.sup.+ can be determined according to step (xi) with the specification data for Δt, {dot over (m)}.sub.1, {dot over (m)}.sub.2.

[0108] According to step (ix), the degree of dehumidification carried out according to step (v; vi) is controlled to the first mass flow {dot over (m)}.sub.1 by the feedback control intervention and/or the supply of mechanical energy ME. This is specifically accomplished in that, from the first differential mass Δm(A.sup.+) and second differential mass Δm(A∞B) determined according to steps (xi) and (xii), according to step (xiii) a tolerable first differential mass Δm(A.sup.+).sub.tol of the raffinate with residual moisture A.sup.+ can be calculated using the definition equation (5) for the tolerable portion δ of extract (C∞B)** in the raffinate with residual moisture A.sup.+ to be specified, namely

[00002]$\begin{array}{cc}\delta =\frac{\Delta {m\left(A^{+}\right)}_{tol}-\Delta m\left(A\infty B\right)}{\Delta m\left(A^{+}\right)-\Delta m\left(A\infty B\right)}.& \left(5\right)\end{array}$

[0109] The tolerable portion δ is then used in the comparison with the first differential mass Δm(A.sup.+) of the raffinate with residual moisture A.sup.+ for controlling when it is revealed that Δm(A.sup.+)>Δm(A.sup.+).sub.tol (FIG. 4; FIG. 1).

[0110] The tea concentrate (C∞B)** freed from extracted tea leaves with residual moisture A.sup.+ is usefully pre-clarified in the centrifugal separator 23 by segregating particles P below the separating limit of the sieve 18a, and then supplied as a pre-clarified tea concentrate (C∞B)* to the filter apparatus 24. The filter apparatus 24 then leaves as a filtered tea concentrate (C∞B) in order, for example, to be further treated to become a tea beverage.

[0111] The above-described first method is carried out over the course of steps (i) and (ii) in the first extraction container 10 that is designed as a discontinuously working homogeneous reaction container. To ensure a desired mass ratio of the second mass m to the first mass M, namely k=m/(M+m), in the first extraction container 10, the second mass m is supplied completely via the first supply connection 12 to the first mass M.

[0112] An extraction by means of the first device 10 is documented using the following process data: [0113] first mass M (1000 L water) with an initial temperature of 84° C.; [0114] second mass m=20 kg tea; [0115] filling time 4.5 min for the first and the second mass M, m; [0116] Turn on a two-disc agitator (first agitator 10a) with a rotational speed of 50 RPM at the beginning of introducing the tea; [0117] the vibration sieve 18, 19 is started up after 5 minutes of brewing; [0118] after another 30 s, the drain valve 14a is opened, and the mixture leaves the extraction container 10 at a flow speed of 18,000 L/h; [0119] the duration of the vibration process is 3.5 min; and [0120] the yield is 880 L extract.

[0121] Second Device (FIG. 2)

[0122] A second device 1* according to the invention for controlling the production of an extract by means of solid-liquid extraction, in particular solid-liquid hot extraction, by means of a second extraction container 100 according to the invention is shown in FIG. 2.

[0123] Just like the first extraction container 10, the second extraction container 100 is designed as a discontinuously working homogeneous reaction container that however, in contrast to the first extraction container 10, has at least one second inner region Ib2 above the first inner region Ib1 (with the first supply connection 12, the first supply valve 12a, the drainage connection 14 and the drain valve 14a) and directly adjacent thereto. Each additional inner region Ib3, . . . , Ibn, where n means a finite number, is arranged above the preceding inner region Ib2, . . . , Ib(n−1), and directly adjacent thereto. Moreover, each inner region Ib2, Ib3, . . . provided above the first inner region Ib1 is assigned another first supply connection 12.1, 12.2, . . . for the primary mixture (A∞B) [tea leaves] with an additional first supply valve 12.1a, 12.2a, . . . . Each additional first supply connection 12.1, 12.2, . . . is assigned another drainage connection 14.1, 14.2, . . . below and at a distance therefrom with another drain valve 14.1a, 14.2a, . . . such that the mixture (C∞B)+A [tea concentrate+extracted tea leaves] obtained in the respective assigned inner region Ib2, Ib3, . . . is discharged as unadulterated as possible from the primary mixture (A∞B). The mixture (C∞B)+A flows to the adjacent inner region Ib1, Ib2, . . . below via the assigned first supply connection 12, 12.1, . . . .

[0124] A second foot area 100.2 of the second extraction container 100 has the drainage connection 14 with the drain valve 14a for completely discharging the mixture (C∞B)+A from the bottommost, first inner region Ib1. Moreover, at the top end of a second headspace 100.1, the supply connection 13 with the supply valve 13a is provided for supplying the compressed gas G with the gas pressure p.

[0125] Via the only supply connection 11 with the supply valve 11a that is located in the top region of the second extraction container 100, the secondary headspace 100.1, the secondary solvent C with the predetermined first mass M is added to the provided inner regions Ib1, Ib2, Ib3, . . . . The free surface N forms in the secondary headspace 100.1 in the topmost inner region.

[0126] Corresponding to a number n of inner regions Ib1 to Ibn, the first mass M is proportionately distributed to these inner regions. Generally, equivalent portions M/n can be assumed in these inner regions, which are designated in FIG. 1 with n=3 inner regions, each with a first partial mass M′, M″ and M′″ (in this case M/3).

[0127] Via the first supply connection 12 and the additional first supply connections 12.1, 12.2, . . . , the primary mixture (A∞B ) [tea leaves] with the predetermined second mass m is added proportionately to the added first mass M, wherein each first partial mass M′, M″, M′″ of the added first mass M has a correspondingly equivalent portion m/n (in this case m/3) that is designated in FIG. 2 as the second partial mass m′, m″ and m′″.

[0128] The second extraction container 100 possesses insulation D for thermal insulation against its environment, and a second stirring apparatus 100a that can be of such a nature that it can ensure a very homogeneous but always product-friendly even distribution of the substrate located therein in each of the inner regions Ib1, Ib2 and Ib3 of the discontinuously working homogeneous reaction container. The first supply connection 12, and all the additional first supply connections 12.1, 12.2, . . . are each connected to a product-friendly, preferably rotating delivery apparatus 22. The delivery apparatus 22 preferably has a screw conveyor 22a that is driven by a drive motor M.sub.A, preferably a controllable drive motor 22b. The primary mixture (A∞B) is preferably kept in a single storage tank 22c from which the primary mixture (A∞B) runs to the respective screw conveyor 22a.

[0129] The drainage connection 14 discharges into the drain line 15 that, viewed in the direction of flow, joins the control valve 16 at a vertical distance from the drainage connection 14 by a supply height H in the direction of gravity. The drain line 15 continues from there into the second device 1*. This part of the second device 1* is identical with the corresponding part of the first device 1.

[0130] Second Method (FIG. 2)

[0131] The second method is carried out over the course of steps (i) and (ii) in the second extraction container 100 that is designed as a discontinuously working homogeneous reaction container. The second mass m is divided into a finite number n of second partial masses m′, m″, . . . , and in so doing into at least two second partial masses m′, m″, . . . , and the second partial masses m′, m″, . . . are each supplied separate from each other to corresponding first partial masses M′, M″, . . . to ensure a desired mass ratio of the second mass to the first mass (concentration k=m/(M+m)) via the first supply connection 12 and additional first supply connections 12.1, 12.2, . . . . Each of these first supply connections can be assigned a delivery apparatus 22. However, a single delivery apparatus 22 can supply the first supply connections 12.1, 12.2, . . . via a suitable controllable valve apparatus with primary mixture (A∞B). The mixture (C∞B)+A obtained by extraction, the tea concentrate C∞B with the extracted tea leaves A, is discharged and supplied via the drainage connection 15 and other drainage connections 14.1, 14.2, . . . .

[0132] Third Device (FIG. 3)

[0133] A third device 1** according to the invention for controlling the production of an extract by means of solid-liquid extraction, in particular solid-liquid hot extraction, by means of a third extraction container 1000, from which a circulation line 25 branching off a drain line 15 runs, is shown in FIG. 3.

[0134] The third extraction container 1000 has a supply line 33 in which, viewed in the direction of flow, is provided upstream from a joining point 27 of a third shutoff valve 32, wherein this part of the supply line 33 serves to supply the secondary solvent C with the first mass M [hot water]. Downstream from the joining point 27, the supply line 33 enters via the supply connection 11 with the supply valve 11a for supplying the secondary solvent C [hot water] or a mixture (A∞B)+C of primary mixture (A∞B) and secondary solvent C [mixture of tea leaves and hot water] via a third foot area 1000.2 into the third extraction container 1000, and penetrates it up to a third headspace 1000.1, and discharges there via an outlet 34 above a free surface N (maximum height of the liquid level). A drainage connection 14 for discharging the secondary solvent C or a mixture (C∞B)+A consisting of an extract (C∞B) and a raffinate A [tea concentrate+extracted tea leaves], leaves the third foot area 1000.1 and transitions there into the drain line 15. The drainage connection 14 is preferably arranged centrally and at the bottom end of the third extraction container 1000, and the supply line 33 is preferably guided concentrically through the drainage connection 14.

[0135] The drain line 15 is at a vertical distance from the drainage connection 14 with the drain valve 14a by the supply height H in the direction of gravity. The drain line 15 joins the control valve 16 and continues from there into the additional third device 1**. This part of the third device 1** is identical with the corresponding part of the first, or respectively second device 1, 1*.

[0136] Upstream from the control valve 16, the circulating line 25 branches at a branching point 26 from the drain line 15 and joins the supply line 33 at the joining point 27. The circulating line 25 is flowed through from the branching point 26 to the joining point 27. Provided inside the circulating line 25, relative to the branching point 26, are first a first shutoff valve 28, a pump 29 for conveying the secondary solvent C, then a dosing apparatus 30 for dosing the primary mixture (A∞B) into the secondary solvent C, and a second shutoff valve 31. The dosing apparatus 30 is connected via the first supply connection 12 to the first supply valve 12a with the product-friendly, rotating displacement pump 22.

[0137] An advantageous embodiment of the third extraction container 1000 provides that at least two third stirring apparatuses 1000a are provided in a liquid-impacted outer region of the third headspace 1000.1 at the edge that are preferably arranged evenly distributed over this outer region. Due to their particular installation position, the third stirring apparatuses 1000a are able to generate a flow movement directed toward the center of the third extraction container 1000 with a flow component oriented in the direction of gravity that helps the formation of a plug flow K.

[0138] The third extraction container 1000 possesses the insulation D for insulating the third extraction container 1000 against its environment. Moreover, at the top end of a third headspace 1000.1, the supply connection 13 with the supply valve 13a is provided for supplying the compressed gas G with the gas pressure p.

[0139] In automatic mode, the control apparatus 21 (not shown in FIG. 3) is additionally connected in terms of signaling to the first shutoff valve 28, the pump 29, the dosing apparatus 30, and the second and the third 31, 32 shutoff valves (e.g., signal connections i, j, l, l1, and l2).

[0140] Third Method (FIG. 3)

[0141] The third method is carried out over the course of steps (i) and (ii) in and with the third extraction container 1000, wherein the first mass M provided according to step (i), which is preferably supplied via the outlet 34 of the supply line 33 discharging above the free surface N, is forcibly discharged over the dwell time τ in the form of the plug flow K oriented in the direction of gravity through the drainage connection 14. A forcibly generated mass flow of the first mass M is continuously added to a mass flow of the second mass m via the dosing apparatus 30 such that a desired mass ratio of the second mass m to the first mass M with the concentration k=m/(M+m) is ensured in the obtained mixture. The continuously obtained mixture is supplied from above to the free surface N of a mixture located in the third extraction container 1000. The dosing of the second mass m into the first mass M ends when the mixture (A∞B)+C [mixture of tea leaves+hot water] first supplied to the third extraction container 1000 has flowed as a mixture (C∞B)+A [tea concentrate+extracted tea leaves] from top to bottom through the third extraction container 1000 in the form of the plug flow K after the expiration of the dwell time τ. During this throughput time that corresponds to the average dwell time, or respectively the brewing time τ, the exchange of substances by extraction occurs. Then the third method is continued according to the steps (iii) to (ix) and in advantageous embodiments according to steps (x) to (xiii).

[0142] In an ideal case, the plug flow K moves at a sinking speed v that results from a maximum filling height L and the average dwell time τ (v=L/τ) so that the average dwell time τ is adjusted by the filling level L and the sinking speed v determined by the delivery of the pump 29. The mixture consisting of tea leaves and hot water (A∞B)+C supplied to the outlet 34 accordingly sinks over the average dwell time τ from the maximum filling height L down into the outlet 14 of the third extraction container 1000, whereby a more or less continuous extraction method is realized.

[0143] The generation of the plug flow K is supported in particular in startup mode, as well as in continuous and shut-off mode by the described third stirring apparatuses 1000a.

[0144] Given the parallel connection of at least two extraction containers 10, or 100, or 1000 that are operated staggered in time in this respective configuration, continuous operation of the controllable vibration or shaking sieve 18, 19 is ensured. This continuous operation increases the production output in comparison to a respective pure batch operation in individual extraction containers 10, or 100, or 1000.

[0145] The following is a list of reference numbers used in the drawings and this description, with reference to the figures in which they first appear.

FIGS. 1 and 2

[0146] 1 First device [0147] 1 Second device [0148] 10 First extraction container [0149] 10′, 10″ Additional first extraction containers [0150] 100 Second extraction container [0151] 10.1 First headspace [0152] 10.2 First foot area [0153] 10a First stirring apparatus [0154] 100.1 Second headspace [0155] 100.2 Second foot area [0156] 100a Second stirring apparatus [0157] 11 Supply connection [0158] 11a Supply valve [0159] 12 First supply connection [0160] 12.1, 12.2, . . . Additional first supply connections [0161] 12a First supply valve [0162] 12.1a, 12.2a, . . . Additional first supply valve [0163] 13 Supply connection [0164] 13a Supply valve [0165] 14 Drainage connection [0166] 14.1, 14.2, . . . Additional drainage connection [0167] 14a Drain valve [0168] 14.1a, 14.2a, . . . Additional drain valve [0169] 15 Drain line [0170] 16 Control valve [0171] 17 First mass flow meter [0172] 18 Separating device [0173] 18a Sieve [0174] 18b Raffinate collecting container [0175] 19 Dehumidifying apparatus [0176] 19a Vibration or shaking drive [0177] 18+19 Vibration or shaking sieve [0178] 20 Second mass flow meter [0179] 21 Control apparatus [0180] 21a Signal transmission lines [0181] 22 Delivery apparatus [0182] 22a Screw conveyor [0183] 22b Drive motor [0184] 22c Storage tank [0185] 23 Centrifugal separator [0186] 24 Filter apparatus [0187] D Insulation [0188] G Gaseous propellant—compressed gas (air, nitrogen, inert gas) [0189] H Supply height [0190] Ib1 First inner region [0191] Ib2 Second inner region [0192] Ib3, . . . , Ib(n−1), Ibn Additional inner regions [0193] M.sub.A Drive motor (general) [0194] ME Mechanical energy [0195] N Free surface (liquid level) [0196] P Particles [0197] a to h Signal connection [0198] n Finite number of inner regions Ib [0199] p Gas pressure

FIG. 3

[0200] 1** Third device [0201] 1000 Third extraction container [0202] 1000.1 Third headspace [0203] 1000.2 Third foot area [0204] 1000a Third stirring apparatus [0205] 25 Circulation line [0206] 26 Branching point [0207] 27 Joining point [0208] 28 First shutoff valve [0209] 29 Pump [0210] 30 Dosing apparatus [0211] 31 Second shutoff valve [0212] 32 Third shutoff valve [0213] 33 Supply line [0214] 34 Outlet [0215] K Plug flow [0216] L Maximum filling height [0217] i, j, l, l1, l2 Signal connection [0218] v Sinking speed

FIG. 4

[0219]

TABLE-US-00001 Special application: Superordinate terms Production of tea concentrate A Primary solvent Carrier material (before extraction) (before extraction) A Raffinate (= primary solvent after Extracted tea leaves extraction) A.sup.+ Raffinate with residual moisture Extracted tea leaves with residual moisture B Transition component Theine and other desirable and undesirable accompanying substances C Secondary solvent Hot water or boiling water (A∞B) Primary mixture Tea leaves (tea raw material) (A∞B) + C Mixture of primary mixture and Mixture of tea leaves and hot water secondary solvent (C∞B) Extract Tea concentrate (filtered in the end step) (C∞B)** Extract freed from raffinate and Tea concentrate freed from extracted residual moisture A.sup.+ tea leaves with residual moisture A.sup.+ (C∞B)* Pre-clarified extract Pre-clarified tea concentrate (C∞B) + A Mixture (extract + raffinate after Tea concentrate + extracted extraction) tea leaves M first mass (C) first mass (hot water) M′, M″, M′″ first partial mass (C) first partial mass (hot water) K Concentration of the primary Concentration of the tea leaves mixture (A∞B) relative to the (A∞B) relative to the hot water C solvent C and the primary mixture and the tea leaves (A∞B) (A∞B) M second mass (A∞B) second mass (tea leaves) m′, m″, m′″ second partial mass (A∞B) second partial mass (hot water) {dot over (m)}.sub.1 first mass flow first mass flow (extract (C∞B) + raffinate with (tea concentrate + extracted tea residual moisture A.sup.+) leaves with residual moisture A.sup.+) {dot over (m)}.sub.2 second mass flow (of the extract second mass flow (of the tea concentrate (C∞B)* freed from raffinate (C∞B)* freed from extracted with residual moisture A.sup.+) tea leaves with residual moisture A.sup.+) Δm(A∞B) second differential mass of the second differential mass of the tea primary mixture (A∞B) over leaves (A∞B) over the time span the time span Δt Δt Δm(A.sup.+) first differential mass of the first differential mass of the extracted raffinate with residual moisture tea leaves with residual moisture A.sup.+ over the time span Δt A.sup.+ over the time span Δt Δm(A.sup.+).sub.tol tolerable first differential mass tolerable first differential mass of the of the raffinate with residual extracted tea leaves with residual moisture A.sup.+ over the time span Δt moisture A.sup.+ over the time span Δt Δt Time span (finite) Dt Time span (infinitesimal) Δ tolerable portion of extract (C∞B) tolerable portion of tea concentrate in the raffinate with residual (C∞B) in the extracted tea leaves moisture A.sup.+ with residual moisture A.sup.+ T Dwell time Brewing time