METHOD FOR DETERMINING AND / OR MONITORING THE CONCENTRATION OF MALTODEXTRIN AND / OR MALTOSE IN A MASHING PROCESS

Description

[0001] The invention relates to a method for continuously determining and / or monitoring a concentration of maltodextrin and / or maltose in a mashing process. The method can be carried out, for example, using a device comprising a sensor unit with at least one mechanically oscillatable unit and at least one piezoelectric element.

[0002] Reliable monitoring of complex processes requires simultaneous knowledge of a wide range of process variables. One example of such a process is the mashing process, which is used, for example, in beer brewing. Malt grist, which is made from grains, particularly barley, is soaked in water and heated. During this process, various malt constituents, such as starches, proteins, and cell wall substances, are dissolved through various enzymatic, physical, and chemical processes. For example, α- and β-amylases break down various starches, particularly amylose and amylopectin in malt grist, into maltose, dextrin, and glucose; gluco-amylases, on the other hand, break down D-maltose into D-glucose.

[0003] During mashing, the aim is generally to adjust the temperature so that a high degree of saccharification of the starch into maltose is achieved. For this reason, it is customary to work within an optimal temperature range for α- and β-amylases. The optimal temperature for α-amylase is T<70°C, and for β-amylase T≈75°C, so two different temperatures must be set successively in two steps to achieve the maximum possible degree of saccharification. In many cases, the presence of soluble amylose is determined during and at the end of the mashing process by refractometric measurement of the refractive index or by a manual iodine test. The time required for saccharification is usually determined empirically and not adjusted to actual processes. It would be desirable to be able to precisely determine the times for the individual steps.

[0004] DE4437684A1 describes a device for measuring the concentration of a liquid in a container, such as fermenting wort during beer production.

[0005] DE4023977A1 ​​describes a method for controlling and regulating the concentration of suspensions, emulsions and solutions.

[0006] DE10035624A1 describes a device and method for fluid diagnosis.

[0007] US5359541A describes the determination of a solution concentration of a liquid in a process.

[0008] DE102016109250A1 describes a method for determining the concentration of components in a multi-component mixture.

[0009] EP 3 129 460 B1 describes a method for controlling a mashing process by analyzing infrared spectra. This determines the ratios of different sugar types. Further parameters are derived by modeling the degradation processes taking place.

[0010] The present invention is therefore based on the object of providing a simple possibility for monitoring the degree of saccharification in a mashing process.

[0011] This problem is solved by a method having the features of the first claim.

[0012] Advantageously, the degree of conversion of maltodextrin to maltose can be determined based on density and sonic velocity. By continuously determining the concentrations of maltodextrin and / or maltose in the mash, the time required for saccharification of the mash can be precisely determined. This allows for optimization of plant availability, the energy required for mashing, and the steam quantities required to keep the mash hot.

[0013] In one embodiment of the process, the temperature of the mash is determined. Both the density and the speed of sound are temperature-dependent variables.

[0014] It is advantageous to consider the influence of temperature on the determination of density and / or speed of sound. The influence of temperature can be compensated for, allowing the concentrations of maltose and / or maltodextrin to be determined more reliably.

[0015] According to the invention, the concentration of the sum of maltodextrin and maltose in the mash is determined based on the density. The density provides information about the concentration, in particular the weight concentration, of the sum of maltodextrin and maltose in the mash. In this way, the total concentration of the two substances in the mash can be determined.

[0016] According to the invention, the ratio of maltodextrin to maltose is determined based on the speed of sound in the mash. The speed of sound in the mash depends on the degree of conversion of maltodextrin to maltose.

[0017] It is further advantageous if at least one value for the speed of sound in the mash is compared with at least one reference value or with a value of a characteristic curve for the speed of sound of maltodextrin and / or maltose as a function of the concentration of maltodextrin and / or maltose.

[0018] In a particularly preferred embodiment of the method, a sensor unit is excited to mechanical vibrations by means of an excitation signal, the mechanical vibrations are received by the sensor unit and converted into a first received signal, a transmitted signal is emitted by the sensor unit and a second received signal is received, and the density is determined based on the first received signal and the speed of sound is determined based on the second received signal.

[0019] A device suitable for carrying out a method according to the invention is, for example, a vibronic sensor. Vibronic sensors are widely used in process and / or automation technology. In the case of level measuring devices, they comprise at least one mechanically oscillating unit, such as a tuning fork, a single rod, or a diaphragm. During operation, this unit is excited to mechanical oscillations by a drive / receiver unit, often in the form of an electromechanical transducer unit, which in turn can be, for example, a piezoelectric drive or an electromagnetic drive. The applicant manufactures a wide variety of corresponding field devices and markets them, for example, under the names LIQUIPHANT or SOLIPHANT. The underlying measuring principles are known in principle from numerous publications.The drive / receiver unit excites the mechanically oscillating unit to mechanical vibrations using an electrical excitation signal. Conversely, the drive / receiver unit can receive the mechanical vibrations of the mechanically oscillating unit and convert them into an electrical reception signal. Accordingly, the drive / receiver unit is either a separate drive unit and a separate receiver unit, or a combined drive / receiver unit. For exciting the mechanically oscillating unit to mechanical oscillations, a wide variety of solutions, both analogue and digital methods, have become known from the state of the art, as described, for example, in the documents DE102006034105A1, DE102007013557A1, DE102005015547A1, DE102009026685A1, DE102009028022A1, DE102010030982A1 or DE00102010030982A1.

[0020] Both the excitation signal and the received signal are characterized by their frequency ω, amplitude A and / or phase Φ. Accordingly, changes in these variables are usually used to determine the respective process variable. The process variable can be, for example, a fill level, a predetermined fill level, or the density or viscosity of the medium, as well as the flow rate. In a vibronic point level switch for liquids, for example, a distinction is made as to whether the oscillating unit is covered by the liquid or is freely oscillating. These two states, the free state and the covered state, are differentiated based on different resonance frequencies, i.e. based on a frequency shift. The density and / or viscosity, in turn, can only be determined with this type of measuring device if the oscillating unit is covered by the medium.In connection with the determination of density and / or viscosity, various possibilities have also become known from the prior art, such as those disclosed in the documents DE10050299A1, DE102007043811A1, DE10057974A1, DE102006033819A1, DE102015102834A1 or DE102016112743A1.

[0021] Furthermore, a previously unpublished German patent application with the file number 102018127526.9 discloses a vibronic multisensor that enables both the vibronic measurement principle and the ultrasonic measurement principle to determine and / or monitor one or more process variables. Such a sensor can measure both density and the speed of sound. If the sensor also has a temperature sensor, the temperature of the mash can also be determined using the same measuring device.

[0022] However, it should be noted that in other configurations, the individual process variables can also be determined, at least in part, by different measuring devices. For example, a separate temperature sensor can be used to determine the temperature. Density and the speed of sound can also be determined independently of each other.

[0023] The invention is explained in more detail with reference to the following figures. They show: Fig. 1 : a schematic sketch of a state-of-the-art vibronic sensor, Fig. 2 two possible embodiments of a sensor unit known per se from the prior art, which are suitable for carrying out the method according to the invention, and Fig. 3 an illustration of a possible embodiment of the method according to the invention.

[0024] In the figures, identical elements are provided with the same reference numerals. The following description refers, without limitation of generality, to the case in which a vibronic sensor 1 is used to implement the method according to the invention.

[0025] In Fig. 1 A vibronic sensor 1 with a sensor unit 2 is shown. The sensor has a mechanically oscillating unit 4 in the form of a tuning fork, which is partially immersed in a medium M located in a container 3. The oscillating unit 4 is excited to mechanical vibrations by means of the excitation / receiving unit 5 and can, for example, be a piezoelectric stack or bimorph drive. Other vibronic sensors, for example, have electromagnetic drive / receiving units 5. It is possible to use a single drive / receiving unit 5, which serves to excite the mechanical vibrations as well as to detect them. However, it is also conceivable to implement one drive unit and one receiving unit each. Shown in Fig. 1 furthermore, an electronic unit 6, by means of which the signal acquisition, evaluation and / or supply takes place.

[0026] In Fig. 2a Two different sensor units 2 are shown by way of example, which are particularly suitable for carrying out a method according to the invention. The mechanically oscillatable unit 4 comprises two oscillating elements 9a, 9b attached to a base 8, which are therefore also referred to as fork tines. Optionally, a paddle can also be formed on the end sides of each of the two oscillating elements 9a, 9b [not shown here]. A cavity 10a, 10b, in particular a pocket-like cavity, is introduced into each of the two oscillating elements 9a, 9b, in which at least one piezoelectric element 11a, 11b of the drive / receiver unit 5 is arranged. The piezoelectric elements 11a and 11b are preferably encapsulated within the cavities 10a and 10b.The cavities 10a, 10b can be designed in such a way that the two piezoelectric elements 11a, 11b are located completely or partially in the area of ​​the two oscillating elements 9a, 9b. Such and similar arrangements are described in detail in DE102012100728A1.

[0027] Another exemplary possible embodiment of a sensor unit 2 is shown in Fig. 2b The mechanically oscillatable unit 4 has two parallel oscillating elements 9a, 9b, here rod-shaped, mounted on a disc-shaped element 12, which can be excited separately to mechanical oscillations, and in which the oscillations can also be received and evaluated separately. Both oscillating elements 9a and 9b each have a cavity 10a and 10b, in which at least one piezoelectric element 11a and 11b is arranged in the area facing the disc-shaped element 12. With regard to the embodiment according to Fig. 2b Reference is again made to the previously unpublished German patent application with the file number 102017130527.0.

[0028] As in Fig. 2b As shown schematically, according to the invention, the sensor unit 2 is, on the one hand, subjected to an excitation signal A in such a way that the oscillatable unit 4 is excited to mechanical oscillations. The oscillations are generated by means of the two piezoelectric elements 11a and 11b. It is conceivable for both piezoelectric elements to be subjected to the same excitation signal A, or for the first oscillating element 11a to be subjected to a first excitation signal A1 and the second oscillating element 11b to be subjected to a second excitation signal A2. It is also conceivable for a first received signal EA to be received based on the mechanical oscillations, or for a separate received signal E A1 or E A2 to be received from each oscillating element 9a, 9b.

[0029] Furthermore, a transmission signal S is emitted from the first piezoelectric element 11a, which is received by the second piezoelectric element 11b in the form of a second reception signal Es. Since the two piezoelectric elements 11a and 11b are arranged at least in the region of the oscillating elements 9a and 9b, the transmission signal S passes through the medium M, provided the sensor unit 2 is in contact with the medium M, and is accordingly influenced by the properties of the medium M. The transmission signal S is preferably an ultrasonic signal, in particular a pulsed one, in particular at least one ultrasonic pulse. However, it is also conceivable for the transmission signal S to be emitted by the first piezoelectric element 11a in the region of the first oscillating element 9a and to be reflected by the second oscillating element 9b. In this case, the second reception signal Es is received by the first piezoelectric element 11a.In this case, the transmitted signal S passes through the medium M twice, which leads to a doubling of the travel time τ of the transmitted signal S and increases the measurement accuracy with regard to the determination of the speed of sound.

[0030] The first EA and second received signal Es result from different measurement methods and can be evaluated independently of each other with respect to different process variables P 1 and P 2 , in this case the density ρ and the speed of sound v. An exemplary embodiment of the method according to the invention is finally shown in Fig. 3 illustrated.

[0031] Fig. 3a shows the density ρ and Fig. 3b the speed of sound v of maltose and dextrin in a mash for different temperatures T, each as a function of the concentration C. The density ρ of the mash is a measure of the total concentration of maltose and dextrin in the mash. However, the density ρ is independent of the degree of conversion. This does not apply to the speed of sound v, which clearly depends on the ratio of maltose to dextrin.

[0032] Furthermore, the density ρ and the speed of sound v are temperature-dependent. Therefore, an additional determination of the mash temperature T is advantageous.

[0033] The density ρ can be determined in case of using a Fig. 2 described vibronic sensor 1 can be determined, for example, using the following equation: ρ = 1 S ⋅ F 0 F Med 2 − 1

[0034] Here, F Med is the oscillation frequency of the oscillating unit 4 in the medium M, F 0 is the reference frequency of the oscillating unit 4 in vacuum or in air, and S describes the sensitivity of the sensor unit 2. The oscillation frequency of the oscillating unit 4 in the medium MF Med can be determined directly from the first received signal EA.

[0035] The speed of sound v of the medium M can in turn be determined from the distance L between the first 11a and second piezoelectric element 11b, which serve as transmitting unit and receiving unit, as well as the propagation time τ of the transmitted signal S from the first 11a to the second piezoelectric element 11b according to the following equation: ν = L τ

[0036] To carry out the embodiment of the method according to the invention shown here as an example, the total concentration of maltose and dextrin in the mash is determined based on the density ρ and the temperature T. Subsequently, a value for the speed of sound is determined and compared with the values ​​given in Fig. 3c The characteristic curves shown here show, as an example, the speed of sound v in the mash as a function of the degree of conversion U, i.e., the ratio of maltose to dextrin in the mash for a Plato concentration of 12°P. The characteristic curve to be used for comparison is therefore selected depending on the total concentration and the temperature. Bezugszeichenliste

[0037] 1Vibronic sensor 2Sensor unit 3Container 4Oscillating unit 5Drive / receiving unit 6Electronic unit 8Base 9a, 9bOscillating elements 10a, 10bCavities 11a, 11bPiezoelectric elements 12Disc-shaped element MMedium P 1 -P 2 Process variables AExcitation signal SSending signal EA First received signal EsSecond received signal ΔΦSpecifiable phase shift ρDensity of the medium vSpeed ​​of sound τTravel time TTemperature

Claims

1. Method for continuously determining and / or monitoring a concentration of maltodextrin and / or a concentration of maltose in a mashing process, comprising the following method steps - Preparation of a mash, - Heating the mash to at least a predetermined temperature (T), - Determining a density (p) of the mash using a vibronic sensor (1) and - Determine a sonic velocity (v) in the mash using the vibronic sensor (1), characterized in that - that a concentration of the sum of maltodextrin and maltose in the mash is determined on the basis of the determined density (p) of the mash, - that a ratio of maltodextrin and maltose is determined on the basis of the determined sonic velocity (v) in the mash, and - that the concentration of maltodextrin and / or the concentration of maltose in the mash is determined on the basis of the determined ratio of maltodextrin and maltose.

2. Method according to claim 1, wherein a temperature (T) of the mash is determined, wherein the concentration of the sum of maltodextrin and maltose in the mash is determined on the basis of the determined density (p) and the determined temperature (T), and wherein the ratio of maltodextrin and maltose is determined on the basis of the determined sonic velocity (v) and the determined temperature (T).

3. Method according to claim 1 or 2, wherein at least one value for the sonic velocity (v) in the mash is compared with at least one reference value or with a value of a characteristic curve for the sonic velocity (v) of maltodextrin and / or maltose as a function of the concentration of maltodextrin and / or maltose.

4. Method according to any one of claims 1 to 3, whereby - a sensor unit (2) of the vibronic sensor (1) is excited to mechanical vibrations by means of an excitation signal (A) - the mechanical vibrations are received by the sensor unit (2) and converted into a first received signal (EA), - a transmit signal (S) is transmitted by the sensor unit (2) and a second receive signal (ES) is received, and - the density (p) is determined using the first received signal (EA) and the speed of sound (v) is determined using the second received signal (ES).