JP2020523188A - Method and mixing device for controlling the introduction of powdered material into a liquid for a batch mixing method - Google Patents

Abstract

The invention relates to a method according to the preamble of claim 1 for controlling the introduction of powdered material into a liquid consisting of at least one component for a batch mixing method, the mixing being carried out for carrying out said method. Apparatus and said method and mixing device ensuring that it avoids the disadvantages of the known prior art. This is inter alia: the powder material (P) is supplied in a discontinuous manner in pulses by the temporal sequence of the metering pulses (i), each pulse being the mass flow rate of the powder material ([Equation 1]), Characterized by the duration of the metering pulse (Δt1) and the time interval between adjacent metering pulses (Δt2), the required stirring and/or shearing and/or shearing of the temporarily available mixed product (M*). A time-dependent power consumption (l(t)), which is proportional to the homogenization force, is revealed: At the end of the time interval (Δt2) between adjacent metering pulses, the time-dependent power consumption (l(t) t)) deviates from its respective assigned value in the time-dependent curve of the reference power consumption (10) either more or less than a predetermined tolerance, to the next metering pulse (i The metering pulse duration (Δt1) of 1) is shortened in the former case and extended in the latter case. [Selection diagram] Figure 1

Description

The invention is a method according to the preamble of claim 1 for controlling the introduction of a powdered material into a liquid consisting of at least one component for a batch mixing method, the introduction and treatment of the powdered material comprising: It relates to a method substantially achieved under the reaction kinetics-related conditions of the residence time behavior of a homogeneous reaction vessel working in a discontinuous manner, and a mixing device for carrying out this method.

In view of the introduction and the uniform distribution of the powder material in the liquid and, where applicable, the dissolution of the powder material in the liquid, a batch-wise mixing method (so-called batch method) or continuous operation Mixing methods (so-called in-line methods) are well known in the mixer art.

In the case of batch processes, the mixing of liquid and powder materials is carried out by reaction kinetics in so-called reaction vessels (mixing tanks) which are operated in a discontinuous manner. A specific amount of liquid is made available in the mixing tank and the powder material is fed until the desired or systematically specified dry substance concentration of the powder material is obtained in the liquid. The powdered material and the liquid are preferably constantly stirred and/or mixed to form a mixed product, which is homogenized in order to evenly distribute the powdered material. The powdered material can be fed in a continuous or discontinuous manner.

In the in-line method, liquid and powder materials are mixed by the reaction kinetics in a so-called continuously operating reaction vessel (mixing tank). Liquid and powder materials are constantly fed to the mixing tank, this powder material is fed in a continuous or discontinuous manner, and the mixed product is mixed tank depending on the amount of liquid and powder material fed. Is discharged in a continuous manner. This is ensured by stirring and/or mixing, or by shearing and homogenizing. Therefore, the theoretical assumption is that the mixed products will have the same composition (eg, dry matter concentration) at any one time and no difference in temperature will occur. The dry matter concentration in the discharged mixed product remains unchanged, i.e. constant, when viewed over the entire mixing process.

The present invention deals exclusively with mixing methods operated using the batch method, in all possible implementations. A mixing method and a related mixing device in this regard are disclosed in Non-Patent Document 1 below, for example.

The above-mentioned mixing device preferably further comprises a so-called vacuum mixer having a mixing tank with stirring and/or shearing and homogenizing devices. For example, the free surface of the liquid, which can have a free filling level of between 0.4 and 4 m in the mixing tank, is assigned according to this height range, for example an atmospheric pressure of 0.2 to 0.8 bar. A negative pressure is applied to the liquid, so that on the one hand it is easier to remove the gaseous constituents from the liquid during the mixing process, and on the other hand the liquid is against atmospheric pressure in the bottom region of the mixing tank under all operating conditions. Have a negative pressure. Powdered material is introduced into the mixing tank through an opening in the tank wall below the free fill level. This opening leads to a tubular inlet connection in the direction of the outside of the mixing tank, which pipe is attached to the inlet connection, for example to a powder storage tank. The inlet connection, and thus the pipe, is configured so that it can be shut off by an inlet valve that controls the supply of the powdered material, so that on the one hand this channel closes the mixing device to the ambient environment and on the other hand. , A quantity of powder material made available in the powder storage tank can be independently supplied to the liquid, if desired, based on the pressure conditions present. In this respect, a mixing device with a preferably discontinuous feed of powdered material is described in WO 03/09312, the latter being common.

A discontinuous supply of powdered material, as disclosed for example in US Pat. No. 6,037,037, is always achieved by the fully open position of the inlet valve, which is designed as a lift valve, so that the risk of clogging of the inlet valve is minimized. Has the advantage of Depending on the duration of each open position, more or less large amounts of powdered material are intermittently introduced into the liquid, so that in principle there is a corresponding risk of agglomeration of the powdered material, such agglomeration occurring: By the time the next powder material enters, it must be completely dissolved by stirring and/or shearing and homogenizing equipment, and efforts should be made at the same time to obtain as uniform a distribution of the powder material as possible. .. In this connection, the intermittent supply of powdered material is the agitation and/or shear and homogenization forces (assigned) necessary to process the temporarily mixed product available at this stage of the mixing process. It is shown that this is explained by an increase in the driving force of the device). In this respect, the curve of the driving force, which is proportional to the power consumption of the allocated drive motor, corresponds approximately to the Gaussian normal distribution curve.

A further complication factor in the mixing process is that it is theoretically assumed that the residence time behavior of a reaction vessel or mixing tank operating in a discontinuous fashion is that the composition of the mixed product is the same at all times. In fact, due to the operational discontinuous feeding of powdered material, more and more unevenly distributed agglomerations of powdered material are produced, which agglomeration is complete at every point of the mixing tank by the next feeding of powdered material. That is not dissolved in. As a result, there is a risk of clogging the mixing tank due to too high dry matter concentration.

Therefore, on the one hand, the possibility that more or less large agglomerates are not completely dissolved and may be present in the mixed product for a long time cannot be ruled out. On the other hand, due to the heterogeneity of the powdered material in the mixed product mentioned above, there is a risk of microbial growth (growth of bacteria) in this mixed product, especially when the mixing tank is heated. Moreover, it becomes remarkable under these thermal conditions. Furthermore, under the last-mentioned conditions, it is increasingly likely that a coating (so-called product deposit) will form on the heated walls of the mixing tank, which on the one hand impedes the transfer of heat and on the other hand. Then shorten the operating time of the mixing tank until the next cleaning cycle comes.

Prevents non-uniformity in the distribution of powdered material and degree of dissolution of agglomerates, as well as disproportionately large fluctuations in the supply of powdered material, and prevents clogging of the mixing device due to excessively high dry substance concentrations in the mixing tank. Since no convenient control mechanism has so far existed, stirring and/or shearing and homogenizing the temporarily available mixed product has so far been probably on the safe side. In a mixing device of the type described here, the whole mixing process takes place more violently than is required for the most part. This overly vigorous treatment can, on the one hand, have a damaging effect on the product and, on the other hand, is detrimental in terms of energy efficiency.

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German Patent Application Publication No. 102015016766

The object of the present invention is to provide a general method for controlling the introduction of powdered materials into a liquid consisting of at least one component for a batch mixing method, and an assigned mixing device for carrying out this method, Further development is made so that the above-mentioned drawbacks of the prior art are eliminated.

The object of the invention is achieved by a method having the features of claim 1. The object of the invention is further achieved by a mixing device which carries out the method with the features of the alternative independent claim 9. An advantageous construction of the mixing device is the subject of dependent claim 10.

The invention, in the context of the method according to the invention, begins with a method for controlling the introduction of a powdered material into a liquid component consisting of at least one component for the well-known batch mixing method, and the term "component". Is understood in the sense that, as a general rule, the components can be separated liquids that are separated from one another and can also be fed separately from each other into the mixing process. Batch mixing methods generally include medium viscosity, high viscosity mixed products with medium to high dry matter concentrations in the end result, and multiple liquids that do not require further processing or require only minor additional processing in downstream processing. Applies to mixed method with components. The introduction and processing of the powdered material, in terms of reaction kinetics, is substantially achieved under the conditions of the residence time behavior of a homogeneous reaction vessel acting in a discontinuous manner.

The method comprises making a quantity of liquid available, supplying powdered material to said liquid in a discontinuous manner, constantly stirring and/or mixing the liquid and powdered material to form a mixed product, A distinction is made from the well-known method that mixed products are homogenized. The powdered material is fed until the time-dependent curve of the dry substance concentration of the powdered material in the mixed product grows to the specified final value.

In the case of the present method, the inventive concept of the solution is that the formulation of the mixed product with respect to at least the time-dependent curve of the dry substance concentration assigned to the specified final value, and the reaction conditions are specified in the form of default data. That's what it means. Furthermore, it provides that the powdered material is delivered in a well-known discontinuous manner in pulses by means of a temporal sequence of metering pulses. In this regard, the reaction conditions, in their preferred form, provide that the powdered material is fed as it is sucked by negative pressure (vacuum) in the head space in the mixing tank with respect to atmospheric pressure. Each metering pulse is characterized by the mass flow rate of the powder material (units are described in [Equation 1], the same applies hereinafter), the duration of the metering pulse (Δt1), and the time interval between adjacent metering pulses (Δt2). To be

The method creates a systematic time-dependent curve of dry matter concentration ending at a specified final value, with either a non-saturating (roughly linear curve) or a saturating (regression curve) dry matter concentration. A distinction is made between.
In the case of non-saturating dry substance concentration curves, the same amount of powdered material can be measured within the framework of the capacity of absorption or within the solubility limit of the liquid at the same time intervals, so that a complete confusion During the homogenization of the product, an approximately linear rising curve with a time-dependent dry matter concentration is adjusted.
In the case of a saturated dry matter concentration curve, a steadily decreasing amount of powdered material can be measured within the framework of the capacity of absorption or within the solubility limit of the liquid at the same time intervals, so that During the homogenization of the complete mixed product, a time-dependent retrograde rising curve of the dry matter concentration is adjusted.

According to the invention, the dry substance concentration time-dependent curve ending at the specified final value is defined by a sequence of well-defined metering pulses.

One important control engineering feature reveals the time-dependent power consumption that is proportional to the stirring and/or shear and homogenization forces required for the temporarily available mixed product. If a defined number of powdered materials is introduced and processed in a mixing process or respectively a mixing tank in a pulse, the time-dependent power consumption always occurs in the form of a nearly normal distribution.

The pulverulent material is distributed uniformly in the absorbing liquid or in the absorbing mixed product, i.e. as uniformly as possible and, if applicable, as soon as it dissolves, as a function of the time-dependent power consumption l(t ) Is reduced to a time-dependent curve of the reference power consumption l ₀ (t), the time-dependent curve of the reference power consumption l ₀ (t) is assigned to the dry substance concentration c(t). Characteristic of the stirring and/or shearing and homogenizing forces to be brought into the homogenized mixed product under the conditions of the curve of dependence. A time-dependent curve of the baseline power consumption l ₀ (t) is stored and used from the default data and depends on the formulation of the mixed product and the reaction conditions of the mixing process.

At the end of the time interval Δt2 between adjacent metering pulses, the time-dependent power consumption l(t) is determined from the respective assigned values in the time-dependent curve of the reference power consumption l ₀ (t). If it is possible to shift either upward or downward by more than the tolerance of, the metering pulse duration Δt1 of the next metering pulse is shortened in the former case and extended in the latter case.

With respect to the time-dependent curves of the non-saturating dry matter concentration c(t), in the first configuration of the method, these curves are the duration Δt1 of the metering pulse and the assignment between adjacent metering pulses. It is provided that each is defined by a fixed duration-time interval ratio V (V=Δt1/Δt2=constant) with respect to the defined time interval Δt2.

The respective curve of the dry matter concentration c(t) rises over a period t, because when viewed over the total duration t of the mixing process, the mass flow rate of the powder material [equation 1] which is constantly metered in pulses. _], the mass flow itself, in the most general case, the mass flow rate of the time dependence of the powder material is from is constant ([number 1] = constant). The mass flow rate of the powdered material is such that for a period of time t, at which the filling level in the mixing tank is almost constant, for many hours, ie (t/Δt2)-hours, a certain constant amount of liquid available of the mixed product. The time-dependent curve of the dry matter concentration c(t) introduced into m _F becomes the following equation (1):

In the most practice-oriented case, as a general rule, the first period of the following relationship is smaller than the second period, so [Equation 3] is an expression using the first proportional constant [Equation 4]. According to (1a), the dry matter concentration c(t) can be approximately set so as to obtain the following results.

With a fixed duration-time interval ratio V (V=Δt1/Δt2=constant), this control-engineering means is based on the next metering pulse and correspondingly shortens the time interval Δt2 between adjacent metering pulses. Or it provides an extension essentially proportionally.

With respect to the time-dependent curves of the saturated dry matter concentration c(t), in the second configuration of the method, these curves are assigned the duration Δt1 of the metering pulse and the distance between adjacent metering pulses. Provided as defined by the varying duration-time interval ratio (V) between the time interval Δt2 and V=Δt1/Δt2≠constant,
The duration if the time-dependent power consumption l(t) deviates from the respective assigned value in the time-dependent curve of the reference power consumption l ₀ (t) by more than a predetermined tolerance. The time interval ratio V is reduced,
Continuation if the time-dependent power consumption l(t) deviates from each assigned value in the time-dependent curve of the reference power consumption l ₀ (t) by more than a predetermined tolerance. The time-time interval ratio V is increased.

The respective curves of the dry matter concentration c(t) rise in a decreasing manner over a period t, because when viewed over the total duration t of the mixing process, the mass flow rate of the powdered material, which is constantly metered in pulses [[ [Equation 1] is actually constant ([Equation 1]=constant), but the duration Δt1 of the metering pulse steadily decreases, and thus the quantity m _{P of} powdered material metered in steadily decreases. .. Mass flow [Number 1] of powder material, the time duration t fill level in the mixing tank is almost unchanged, is introduced into the volume V _M available substantially unchanged mixed product ([6 ]), the density ρ _M of the mixed product M increases according to the time-dependent curve of the dry matter concentration c(t), and the latter half follows the equation (2) using the second proportionality constant [Equation 7]. expressed:

These control-engineering means with a variable duration-time interval ratio V require that the duration Δt1 of the metering pulse can be shortened or extended without changing the time interval Δt2 between adjacent metering pulses, or If the duration Δt1 of the metering pulse is not changed, it is necessary that the time interval Δt2 between adjacent metering pulses can be extended or shortened in a suitable manner.

Therefore, the control-engineering means according to the invention essentially comprises, in both configurations of the method, the duration Δt1 of the metering pulse and the time interval Δt2 between adjacent metering pulses such that At each end of the time interval Δt2, the power consumption l(t) determined as a function of time for stirring and/or shearing and homogenizing the temporarily available mixed product is equalized at this point. The fact that the time-dependent curve of the reference power consumption l ₀ (t) required to process the processed mixed product is chosen to approach within the framework of the practice-oriented acceptable tolerances Consists of.

In order to design the metering of the powder material as trouble-free as possible, a method has been proposed in which the mass flow rate of the powder material [Equation 1] is constant over the duration of the metering pulse. A controllable opening for the supply of powdered material melts only in one of the fully open or closed positions.

In order to control the mixing process to be handled as easily as possible, in other configurations of the method, shortening or lengthening the duration of the metering pulse results in a power consumption that shifts upward or a power consumption that shifts downward. Is provided in each case when leaving the current range specified by the permissible overcurrent or the permissible undercurrent. The permissible overcurrent and the permissible undercurrent are each determined by the percentage proportion of the assigned time-dependent curve of the reference power consumption.

In this regard, in order to ensure the most accurate control action possible, in another configuration of the method, the degree of shortening or extending the duration of the metering pulse is further dependent on the assigned time dependence of the reference power consumption. It is proposed that it be determined as a function of the degree of time-dependent power consumption deviation from the curve of.

In order to produce working data obtained in the actual work for a particular formulation that can be used for subsequent mixing processes with the same formulation, in another configuration of the method, a powdered material into at least one liquid Further prescription-dependent default data underlying the control of the introduction of are obtained and stored from empirical values of previous mixing processes, said default data being the mixing or solution temperature, pressure above the liquid column, liquid column Reaction pressure resulting from the pressure above, the rotation speed of the device for stirring and/or shearing and homogenization, and the permissible overcurrent and permissible undercurrent depending on the assigned curve of the reference power consumption. Is provided.

In order to produce working data obtained in the actual work for a particular formulation that can be used for subsequent mixing processes with the same formulation, in another configuration of the method, a powdered material into at least one liquid The convenient prescription-dependent control parameters obtained in the course of the control of the introduction, namely the duration of the metering pulse and the time interval between adjacent metering pulses, are stored and used for control after the same prescription. Are provided.

Mixing device The mixing device for carrying out the method comprises a feed connection for supplying a liquid, an outlet connection for discharging the mixed product, a stirring device and/or a shearing and homogenizing device. It constitutes a well-known mixing tank. An inlet valve with a valve closing member is located on the mixing tank. The inlet valve can be adjusted by the valve closing member between fully closed (closed position) or fully opened (open position). The powdered material is introduced into the liquid by means of an inlet valve and the valve closing member can be moved to a closed or open position by means of a control device assigned to the inlet valve.

According to the invention, the control device provides a mixing device with prescription-dependent default data and prescription-dependent control parameters in the form of the duration of the metering pulse and the time interval between adjacent metering pulses. Furthermore, according to the invention, the control device comprises at least one signal pickup configured as a measuring device, the signal pickup detecting a time-dependent power consumption of the stirring device and/or the shearing and homogenizing device. .. With these properties, the controller causes the closed or open position of the valve closure member to be associated with default data and control parameters as a function of time-dependent power consumption.

In order to maximize the use of the inlet valve, which is configured as a lift valve and exclusively delivers the powdered material in the fully open position, and consequently minimizes the susceptibility to clogging from the start, further examples in this regard As a result, in order to prevent dead spaces and hollow spaces in the valve housing region of the inlet valve on which the powder acts, in an advantageous embodiment, the valve closing member has a cylindrical shape with the same diameter, at least in the region on which the powder acts. It is provided that a valve plate configured as a rod and having the same diameter is molded on the cylindrical rod. When the inlet valve is located in the fully open position, it does not constitute a flow obstruction on the one hand for this embodiment, and on the other hand is located in the vicinity of the wall of the valve housing and therefore of the complete pipe flow. The valve plate so that it does not form a seat seal received at the valve plate that is in any way contacted only by the stagnation flow, which lies outside the defined flow region and thus closes the wall in said end region. The provided valve closure member extends from the fully constituted flow of powdered material to its maximum extent.

The invention is represented in more detail by the following description and the accompanying drawings and claims. The present invention is realized in a wide variety of configurations of methods for controlling the introduction of powdered materials into a liquid consisting of at least one component for a batch mixing method, but in order to carry out the preferred method and this method. The mixing device is described in the drawing.

A schematic diagram of a mixing apparatus for a batch mixing method is shown. 2 shows an inlet valve for feeding powdered material to the mixing device according to FIG. 1 in a perspective view in half section, omitting the control head housing. In a qualitative representation of the method, a metering with a constant metering pulse duration Δt1 and a time interval Δt2 between adjacent metering pulses is used to basically represent the characteristics of the control according to the invention. The time-dependent power consumption l(t) in the pulse sequence is shown, and the time-dependent curve of the non-saturating dry matter concentration c(t) is adopted as a reference. In a qualitative representation of the method, a time-dependent power consumption in a sequence of metering pulses with a constant metering pulse duration Δt1/2 and a time interval Δt2/2 between adjacent metering pulses. 1(t) and the time-dependent curve of the dry matter concentration c(t) according to FIG. 3 is adopted as a reference. In a qualitative representation of the method, the duration of the metering pulse is constant in order to realize an almost linear rising curve of the time dependence of the (unsaturated) dry matter concentration according to FIGS. 3 and 4. 3 shows the time-dependent power consumption l(t) in a larger sequence of metering pulses with a constant time interval Δt2 between adjacent metering pulses with Δt1. In a qualitative representation of the method, adjacent metering pulses have a steadily decreasing duration Δt1 of metering pulses to achieve a time-dependent decreasing curve of the (saturating) dry matter concentration. 3 shows the time-dependent power consumption l(t) in a series of metering pulses with a constant time interval Δt2 between.

Mixing device (Figs. 1 and 2)
The mixing device 1000 comprises, inter alia, a mixing tank 100 which is composed of a tank casing 100.1, preferably of cylindrical shape, an upper tank bottom 100.2 and a lower tank bottom 100.3. The lower tank bottom 100.3 is preferably downwardly tapered, mainly in the form of a cone or cone, with an outlet connection 100.4 for the mixed product M at the lower end. In the mixing tank 100, the liquid F is made available in a liquid volume m _F via the supply connection 100.5 which sets the free filling level N, whereby, in principle, at negative pressure relative to atmospheric pressure. A pressure p above a liquid column exists in the mixing device 1000 (eg, vacuum mixer) discussed herein.

An inlet valve 20 is arranged in the tank casing 100. 1 or the lower tank bottom 100.3. The inlet valve 20 serves to supply the powder material P supplied via the supply line 18 to the liquid F or the mixed product M in a discontinuous manner at the powder material mass flow rate [Equation 1]. Assigned to the inlet valve 20 is a controller 30 that communicates with the control head housing 14 of the inlet valve 20 via signal line 22 and moves the inlet valve 20 to an open or closed position as required. Within the mixing tank 100, an agitator 24 is arranged, which preferably extends into the area of the lower tank bottom 100. 3 and is preferably arranged centrally by means of a mechanically acting first drive motor 40. It is driven at a low first rotation speed n1. The necessary stirring action is carried out, for example, by re-sending the liquid F or the mixed product M via a circulation line (not shown), causing the liquid F or the mixed product M to enter the mixing tank 100, preferably tangentially, It is also possible to achieve or support by mechanical means of flow.

Instead of, or in addition to, the stirring device 24, a shearing and homogenizing device 26 driven by a second drive motor 50 at a significantly higher second rotational speed n2 is preferably provided in the lower tank bottom 100.3. It is preferably provided eccentrically in the lower region. Said shearing and homogenizing device preferably sucks liquid F or mixed product M from above on the one hand and annularly discharges liquid F or mixed product M on the other hand in the region near the wall of the lower tank bottom 100.3. However, a circulating flow from the outside to the inside is preferably configured in the mixing tank 100. On passing through the shearing and homogenizing device 26, the liquid F and the powdered material P, or the resulting mixed product M, are very strongly mechanically mixed and preferably homogenized thereby.

The inlet valve 20 is configured as a lift valve (Fig. 2). It has a valve seat 2 a and a valve plate 8 a in the valve housing 2 which interacts with the valve seat 2 a, which valve plate is constructed on the valve closing member 8. In principle, the valve closing member 8 receives a seat seal 10 that provides a seal in interaction with the valve seat 2a when the inlet valve 20 is in the closed position. The valve seat 2a has a seat opening 2b, through which the powder material P supplied from the supply line 18 via the pipe connection 2c is introduced into the liquid F (FIG. 1).

Since the waiting liquid F above the connection point of the inlet valve 20, which is preferably arranged directly on the wall of the mixing tank 100, constitutes the height h (FIG. 1) by its liquid column, the area of the connection point mentioned above. The static pressure at, and hence the static pressure in the region of the seat opening 2b is composed of the pressure above the liquid column p (preferably negative pressure) and the static pressure generated from the height h of the liquid column. For example, in the case of a vacuum mixer having a negative pressure of p=0.2 to 0.8 bar and a liquid column height h=0.2 to 4 m assigned according to this pressure range, the negative pressure with respect to the atmospheric pressure is It is still always in the region of the seat opening 2b, so that the seat opening 2b is sucked out of the mixing tank 100 and thus the powder material P is sucked in. The seat opening 2b can be adjusted by the valve plate 8a between a fully closed closed position or a fully open open position. The valve housing 2 is connected via a lantern type housing 4 to a drive housing 6 for driving the valve closing member 8. Preferably a pressure medium actuated spring/piston drive, the return spring 12 closing the valve closing member 8 when no pressure means, in principle, preferably compressed air, act on the drive housing 6. Move to position. A valve rod 8b acting on the valve plate 8a of the valve closing member 8 and guided through the drive housing 6 to the control head housing 14 serves to guide the valve closing member 8 axially on the drive side. The valve closing member 8 is configured as a cylindrical rod having the same diameter in at least the region of the valve closing member 8 on which the powder acts, and the valve plate 8a having the same diameter is formed on this rod. Thanks to the design design, hollow spaces and dead spaces in the valve housing 2 are prevented in the movement region of the valve closing member 8 where the powder acts, and the valve closing member 8 is closed at its end with the valve plate 8a. And with the associated seat seal 10, it is possible to maximally withdraw from the area of the valve housing 2 through which the flow completely passes.

The controller 30 (FIG. 1) has at least one signal pickup 16. The at least one signal pickup 16 is, for example, a mixing parameter measuring device, which may be, for example, the pressure p above the liquid column in the mixing tank 100, the mixing or solution temperature T of the liquid F, the dry substance concentration c or the drying. These include the time-dependent curve c(t) of the substance concentration, the rotation speeds n1, n2, and the time-dependent power consumption 1(t) of the stirring and/or shearing and homogenizing devices 24, 26. The signal pickup 16 is shown by way of example in FIG. 1 for the time-dependent power consumption l(t) of the second drive motor 50 of the shearing and homogenizing device 26. In addition, or in the alternative, it is likewise possible to provide further measuring devices which reveal other mixing parameters.

Method (FIGS. 3 to 6 in combination with FIGS. 1 and 2)
The introduction and treatment of the powdered material P is achieved substantially under the kinetics-related conditions of the residence time behavior of a homogeneous reaction vessel, which work in a discontinuous manner. The method is such that a certain amount of liquid m _F is made available in the mixing tank 100 (feed via feed connection 100.5) and the powder material P is brought to this liquid F in the most common case. Is supplied in a discontinuous manner via the inlet valve 20 at a powder material mass flow rate [Equation 1], which may be a time-dependent powder material mass flow rate [Equation 1](t), in a known manner. To be distinguished. The liquid F and the powdered material P are constantly stirred and/or mixed to form a mixed product M, which is homogenized. The powder material P is fed until the time-dependent curve c(t) of the dry substance concentration of the powder material P in the mixed product M grows to the specified final value C _E.

In the case of the mixing method described here, the formulation and reaction conditions of the mixed product M with respect to the time-dependent curve c(t) of the dry matter concentration assigned to at least the specified final value C _E are the default data. Specified in the D form.

The powder material P is supplied in a discontinuous manner over a period t in pulses by a temporal sequence of metering pulses i (FIGS. 3 and 4), each pulse being a mass flow rate of the powder material [Equation 1] and a metering pulse. It is characterized by a pulse duration Δt1 and a time interval Δt2 between adjacent metering pulses. The mass flow rate [Equation 1] of the powder material is essentially the time-dependent mass flow rate [Equation 1] (t) of the powder material, as already indicated, and in the case of the subject of the present application, the inlet valve Because of the structure and switching properties of 20, it is assumed that the mass flow rate [Equation 1] of the powder material is largely time-independent and thus constant ([Equation 1]=constant).

The time-dependent power consumption l(t), which is also plotted in FIG. 3 over the corresponding time period t, for the duration Δt1 of the metering pulse according to FIG. 3 is, for example, the second drive motor 50 of the shearing and homogenizing device 26. Have been revealed or measured in. This time-dependent power consumption is proportional to the stirring and/or shearing and homogenizing forces required for the temporarily available mixed product M* in the mixing tank 100 immediately after the metering pulse i (FIG. 1). However, the stirring and/or shearing and homogenizing forces are applied by the stirring and/or shearing and homogenizing devices 24,26. The time-dependent power consumption l(t) curve resembles a Gaussian normal distribution curve, rising with the intermittently advancing mass flow of the powder material [Equation 1] to reach the maximum value, and then the powder material Following the dissolution P, i.e. in the case of achieving a homogenized mixed product M, there is a gradual decrease to the time-dependent power consumption l(t) required for this homogenized mixed product M.

According to the invention, this typical behavior is used in control engineering terms, in that the time-dependent curve l ₀ (t) of the reference power consumption is taken from the default data D, which curve is , A characteristic of the stirring and/or shearing and homogenizing forces to be brought into the homogenized mixed product M.

If the time interval Δt2 between adjacent metering pulses is not sufficient for the dissolution, mixing and homogenization of the metered quantity of powdered material m _P =[Equation 1]Δt1, then the power consumption shifts upward in a time-dependent manner. In this state of the mixed product M*, in which l*(t) has been measured and thus is temporarily available, the updated metering pulse i is not yet displayed at the end of the time interval Δt2 between adjacent metering pulses. .. Under comparable conditions, if a time-dependent downward power consumption l**(t) is observed, this is due to agitation and/or shear, which is also defined by the time interval Δt2 between adjacent metering pulses. And may indicate that the homogenization step is too long or that the metered quantity of powdered material m _P is not suitable for this step.

As soon as the powdered material P is evenly distributed in the absorbing liquid F or the absorbing mixed product M, ie as evenly as possible and, if appropriate, dissolved, the time-dependent power consumption l(t ) Is reduced to a time-dependent curve of the reference power consumption l ₀ (t), the time-dependent curve of the reference power consumption l ₀ (t) is assigned to the dry substance concentration c(t). Characteristic of the stirring and/or shearing and homogenizing forces to be brought to the homogenized mixed product M under the conditions of the dependence curve (FIGS. 3-5: reference power consumption l ₀ (t) (See FIG. 6: gradually decreasing time-dependent curve of reference power consumption l ₀ (t)). Time dependent curve of the reference power consumption l _{0 (t)} at time t = 0 only pure liquid F is available, the initial value l _{0 (t} = 0) of the reference power = starting with l ₀ (See Figures 3-6). In this regard, the curve of reference power consumption l ₀ (t) is stored in the default data D and depends on the formulation of the mixed product M and the reaction conditions of the mixing process.

At the end of the time interval Δt2 between adjacent metering pulses, the time-dependent power consumption l(t) is determined from the respective assigned values in the time-dependent curve of the reference power consumption l ₀ (t). If it deviates more than the tolerance of, there may be either an upward deviation or a downward deviation (see FIGS. 3 and 4), but the metering pulse duration Δt1 of the following metering pulse is In the case of, it is shortened, in the latter case, it is extended. The permissible error is configured by designating the allowable overcurrent ΔI1 and the allowable undercurrent ΔI2 (FIG. 3).

The shortening case is shown in FIG. 4, in which case the duration Δt1 of the metering pulse and thus also the assigned time period Δt2 between adjacent metering pulses is for example halved (Δt1/ 2; Δt2/2). Then, also in the case of this metering mode, at the end of the time period Δt2/2 between adjacent metering pulses, within the framework of the specified tolerances, the time which makes the necessary correction in the above sense essential. A check is made as to whether there is a power consumption l*(t), l**(t) that deviates above or below the dependency.

If the power consumption l*(t), l**(t) deviates from the current range determined by the allowable overcurrent ΔI1 or the allowable undercurrent ΔI2, respectively, upward or downward in a time-dependent manner, The duration of the pulse Δt1 is shortened or extended. The permissible overcurrents and the permissible undercurrents ΔI1, ΔI2 are preferably determined respectively by the percentage proportion of the assigned time-dependent curve of the reference power consumption l ₀ (t). Furthermore, the degree of shortening or lengthening of the duration Δt1 of the metering pulse is preferably the deviation of the time-dependent power consumption l(t) from the assigned time-dependent curve of the reference power consumption l ₀ (t). Is determined as a function of the degree of. The permissible overcurrent ΔI1 and permissible undercurrent ΔI2 finally determined by the respective formulation of the mixed product M can be part of the default data D of the mixing process.

A suitable prescription-dependent control parameter S obtained in the course of controlling the introduction of the powder material P into the at least one liquid F, namely the metering pulse duration Δt1 and the time interval Δt2 between adjacent metering pulses, is stored, It is used for the subsequent control of the same prescription.

The controller 30 of the mixing device 1000 provides, according to the invention, a prescription-dependent default data D and a prescription-dependent control parameter S in the form of a metering pulse duration Δt1 and a time interval Δt2 between adjacent metering pulses. It is set to be possible. Furthermore, the control device 30 comprises at least a signal pickup 16 configured as a measuring device for detecting the time-dependent power consumption l(t) of the stirring device 24 and/or the shearing and homogenizing device 26 (FIGS. 3, 4). (FIG. 1) is further included. According to the invention, the control device 30 determines, as a function of the time-dependent power consumption l(t), the closed position or the opening of the valve closing member 8 (FIG. 2) in relation to the default data D and the control parameter S. Give rise to a position.

This method yields a time-dependent curve of dry matter concentration c(t) that systematically ends with a specified final value C _E , and a time-dependent curve of non-saturating dry matter concentration c(t). (Generally linear time-dependent curves; see FIGS. 3-5) or between time-dependent curves of saturating dry matter concentration (gradually decreasing time-dependent curve; see FIG. 6). A distinction should be made. The time-dependent curve of the dry matter concentration c(t) ending at the specified final value C _E is defined by the sequence of the particular metering pulse i, ie the duration Δt1 of the metering pulse and between adjacent metering pulses. It is clearly defined by the time interval Δt2.

As can be explained by the above equations (1, 1a) (c(t) = k1 V t), there is no saturation starting with c(t=0)=0 for pure liquid F (Fig. 5). With regard to the time-dependent curve of the dry matter concentration c(t), in the configuration of the method, this curve is between the duration Δt1 of the metering pulse and the assigned time interval Δt2 between adjacent metering pulses. It is defined by a fixed duration-time interval ratio V (V=Δt1/Δt2=constant). In the case of a deviation of the reference power consumption l ₀ (t) from the time-dependent curve, according to the invention, at a constant duration-time interval ratio V, the duration Δt1 of the metering pulse is (e.g. 3 is shortened or extended (as qualitatively shown in FIG. 4 in contrast to 3). This control-engineering means with a fixed duration-time interval ratio V necessarily proportionately, based on the subsequent metering pulse i, a corresponding shortening or lengthening of the time interval Δt2 between adjacent metering pulses. Bring.

With respect to the time-dependent curve (FIG. 6) of the saturable dry matter concentration c(t) as can be explained by equation (2) [Equation 9] above, in a further configuration of the method, this curve is Defined by the varying duration-time interval ratio V between the duration Δt1 of the metering pulse and the assigned time interval Δt2 between adjacent metering pulses (V=Δt1/Δt2≠constant),
Persistence if the time-dependent power consumption l(t) deviates from the respective assigned value in the time-dependent curve of the reference power consumption l ₀ (t) by more than a specified tolerance. The time-time interval ratio V is reduced,
Persistence if the time-dependent power consumption l(t) deviates from the respective assigned values in the time-dependent curve of the reference power consumption l ₀ (t) by more than a specified tolerance. The time-time interval ratio V is increased.

The respective curves of the dry matter concentration c(t) start from c(t=0)=0 in the pure liquid F and gradually increase over the period t (FIG. 6), because of the total mixing process. The mass flow rate [Equation 1] of the powder material, which is constantly metered in pulses, is actually preferably constant ([Equation 1]=constant) when viewed over a duration t, but the duration Δt1 of the metering pulse is steady. , And therefore the amount of powdered material m _P to be metered in steadily decreases. Mass flow rate of powder material [Number 1] is the filling level N is substantially invariant mixing process the entire duration t in the mixing tank 100, into the volume V _M available substantially unchanged mixed product introduced (V _M ≒ constant), density [rho _M of the mixed product M increases, i.e. according to the time-dependent curve of the dry substance concentration c (t) of grow into given final value C _E.

FIG. 6 shows a steady decrease in the respectively metered quantity of powdered material m _P =[Equation 1]Δt1 as a function of the time-dependent curve of the dry matter concentration c(t), which Once again, each assigned time-dependent power consumption l(t) has an assigned time-dependent curve of the reference power consumption l ₀ (t) at the end of the time interval Δt2 between adjacent metering pulses. Approaching or matching as much as possible. In this respect, the curve shows a successful mixing process, which on the one hand protects the mixed product M and on the other hand is constructed in an energy-efficient manner. No control engineering measures are required in the sense explained above. Only if a deviation from the permissible overcurrent or undercurrent ΔI1, ΔI2 occurs, the control mechanism is engaged in a manner similar to that described for the first method in connection with FIGS. 3 and 4.

These control engineering measures with a variable duration-time interval ratio V allow the control device 30 to shorten or extend the duration Δt1 of the metering pulse without changing the time interval Δt2 between adjacent metering pulses. Or if the duration Δt1 of the metering pulse is not changed, it is necessary that the time interval Δt2 between adjacent metering pulses can be lengthened or shortened in a suitable manner.

Therefore, the control-engineering means according to the invention is essentially such that, in both configurations of the method, the duration Δt1 of the metering pulse and the time interval Δt2 between adjacent metering pulses are the time between adjacent metering pulses. At each end of the interval Δt2, the power consumption l(t) determined as a function of time for stirring and/or shearing and homogenizing the temporarily available mixed product M* is homogeneous at this point. Chosen to approach the time-dependent curve of the reference power consumption l ₀ (t) required to process the liquefied mixed product M within the framework of a practically-oriented acceptable tolerance. It consists of the fact that

1000 Mixing device 100 Mixing tank 100.1 Tank casing 100.2 Upper tank bottom 100.3 Lower tank bottom 100.4 Outlet connection 100.5 Supply connection 20 Inlet valve 30 Control device 40 First drive motor 50 Second Drive motor 2 valve housing 2a valve seat 2b seat opening 2c pipe connection 4 lantern type housing 6 drive housing 8 valve closing member 8a valve plate 8b valve rod 10 seat seal 12 return spring 14 control head housing 16 signal pickup 18 supply line 22 signal line 24 stirrer 26 shearing and homogenizing device D default data F liquid l ₀ initial value of reference power consumption (because of homogenized mixed product M; l ₀ (t=0)=l ₀ )
l ₀ (t) Reference power consumption l(t) Time-dependent power consumption (because of temporarily available mixed product M*)
(L ^* (t)) Power consumption that shifts upward (l ^** (t)) Power consumption that shifts downward ΔI1 Allowable overcurrent ΔI2 Allowable undercurrent M Mixed product M* Temporarily available Do mixed product N filling level P powder material S control parameter T mixture or solution temperature V duration - density c dry matter concentration c (t) dry substance concentration of the volume [rho _M mixed product of the time interval ratio V _M mixture compound Time-dependent curve C _E Final value specified (of time-dependent curve)
h Liquid column height i Metering pulse k1 First proportional constant [Equation 4]
k1 Second proportionality constant [Equation 7]
m _{F a} certain amount of liquid m _{P a} measured amount of powdered material [Equation 1] Mass flow rate of powder material [Equation 1] (t) Time dependency Mass flow rate of powder material n1 First rotation speed n2 Second rotation speed p Pressure above liquid column t Time (general) or entire mixing process Time interval Δt1 Duration of metering pulse Δt2 Time interval between metering pulses

Claims (10)

A method for controlling the introduction of a powder material (P) into a liquid (F) consisting of at least one component for a batch mixing method, the method comprising:
Under the conditions of the residence time behavior of a homogeneous reaction vessel, the introduction and treatment of said powder material (P) acting in a discontinuous manner,
A quantity (m _F ) of liquid is made available and the powder material (P) is fed to the liquid (F) in a discontinuous manner,
The liquid (F) and the powdered material (P) are constantly stirred and/or mixed to form a mixed product (M), the mixed product (M) being homogenized,
-The powder material (P) has a final value ( _CE ) for which the time-dependent curve of the dry substance concentration (c(t)) of the powder material (P) in the mixed product (M) is designated. ) Is achieved in such a way that it is supplied until
The formulation of the mixed product (M) with respect to the time-dependent curve of at least the dry substance concentration (c(t)) assigned to the specified final value (C _E ) and the reaction conditions are the default data Designated in the form of (D),
The powder material (P) is supplied in a discontinuous manner in pulses according to the temporal sequence of the metering pulse (i), each pulse being a mass flow rate of the powder material ([Equation 1]), the metering. Characterized by the duration of the pulse (Δt1) and the time interval between adjacent metering pulses (Δt2),
The time-dependent curve of the dry matter concentration (c(t)) ending at the specified final value (C _E ) is defined by the sequence of well-defined metering pulses (i),
A time-dependent power consumption (l(t)) proportional to the stirring and/or shear and homogenization forces required for the temporarily available mixed product (M ^* ) is revealed,
The stirring and/or shearing and homogenization to be brought to the homogenized mixed product (M) under the conditions of the assigned time-dependent curve of dry matter concentration (c(t)) A time-dependent curve of the reference power consumption (l ₀ (t)) showing the characteristics of the conversion is used from the default data (D),
At the end of the time interval (Δt2) between adjacent metering pulses, the time-dependent power consumption (l(t)) is the time-dependent curve of the reference power consumption (l ₀ (t)). If the measured pulse duration (Δt1) of the next metering pulse (i) deviates from its respective assigned value in either upward or downward by more than a predetermined tolerance, it shortens in the former case. And the latter case is extended. The time-dependent curve of the non-saturating dry matter concentration (c(t)) shows the duration of the metering pulse (Δt1) and the assigned time interval between adjacent metering pulses (Δt2). Method according to claim 1, characterized in that it is defined by a fixed duration-time interval ratio (V) between (V=Δt1/Δt2=constant). A time-dependent curve of the saturable dry matter concentration (c(t)) shows the duration of the metering pulse (Δt1) and the assigned time interval between adjacent metering pulses (Δt2). Defined by the varying duration-time interval ratio (V) (V=Δt1/Δt2) between
The time-dependent power consumption (l(t)) is less than the predetermined tolerance from the respective assigned values in the time-dependent curve of the reference power consumption ( ₁₀ (t)) When it deviates significantly upward, the duration-time interval ratio (V) is reduced,
The time-dependent power consumption (l(t)) is less than the predetermined tolerance from the respective assigned values in the time-dependent curve of the reference power consumption ( ₁₀ (t)) The method according to claim 1, characterized in that the duration-time interval ratio (V) is increased if it deviates significantly downwards. 4. Method according to any one of claims 1 to 3, characterized in that the mass flow rate ([Equation 1]) of the powder material is constant over the duration ([Delta]t1) of the metering pulse. The shortening or lengthening of the duration (Δt1) of the metering pulse is achieved in each case where the upward power consumption (l ^* (t)) or the downward power consumption (l ^** (t)) is different. The resulting overcurrent and the allowed undercurrent (ΔI1, ΔI2) are caused by leaving the current range determined by the allowed overcurrent (ΔI1) or the allowed undercurrent (ΔI2). 5. A method according to any one of claims 1 to 4, characterized in that it is determined by a percentage percentage of the assigned time-dependent curve of the respective reference power consumption ( ₁₀ (t)). The degree of shortening or lengthening of the duration (Δt1) of the metering pulse is determined by the time-dependent power consumption (l) from the assigned time-dependent curve of the reference power consumption (l ₀ (t)). Method according to any one of claims 1 to 5, characterized in that it is determined as a function of the degree of deviation of (t), l ^* (t), l ^** (t)). Default data (D) depending on the further formulation underlying the control of the introduction of the powdered material (P) into the at least one liquid (F) are obtained and stored from empirical values of previous mixing processes. ,
The default data (D) is
. Mixing or solution temperature (T),
・Pressure (P) above the liquid column,
The speed of rotation of the device for stirring and/or shearing and homogenization (n1, n2), and the permissible overcurrent (ΔI1) depending on the assigned curve of the reference power consumption (l ₀ (t)) ) And the allowable undercurrent (ΔI2)
7. The method according to any one of claims 1 to 6, characterized in that A convenient prescription-dependent control parameter (S) obtained in the course of controlling the introduction of the powdered material (P) into the at least one liquid (F), ie: the duration of the metering pulse (Δt1) And, said time interval (Δt2) between adjacent metering pulses.
The method according to any one of claims 1 to 7, characterized in that it is stored and used for subsequent control of the same formulation. Supply connection (100.5) for supplying liquid (F), outlet connection (100.4) for discharging mixed product (M), stirrer (24) and/or shear and An inlet valve (20) having a homogenizer (26) and a valve closing member (8) is disposed on the mixing tank (100), and the valve closing member (100) is provided. 8) The inlet valve (20) can be adjusted between fully closed (closed position) or fully opened (open position) by 8) the inlet for introducing powdered material (P) into the liquid (F) The valve (20) comprises a control device (30) assigned to the inlet valve (20) capable of moving the valve closing member (8) to the closed position or the open position. A mixing device for carrying out the method according to 1.
The controller (30) is responsive to prescription in the form of default data (D), and the duration of the metering pulse (Δt1) and the prescription in the form of the time interval between adjacent metering pulses (Δt2). Control parameter (S)
The control device (30) has at least one signal pickup (16) configured as a measuring device, the signal pickup comprising the stirring device (24) and/or the shearing and homogenizing device (26). Time-dependent power consumption (l(t)) of
The controller (30), in relation to the default data (D) and the control parameter (S), as a function of the time-dependent power consumption (l(t)), the valve closing member (8). 2.) The mixing device for producing the closed position or the open position of 3). The valve closing member (8) is configured as a cylindrical rod having the same diameter, at least in the region where the powder acts, and a valve plate (8a) having the same diameter is formed on the cylindrical rod. The mixing device according to claim 9, wherein

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