WO2007125555A1

WO2007125555A1 - Device for controlling and managing the viscosity and density of a fluid

Info

Publication number: WO2007125555A1
Application number: PCT/IT2006/000303
Authority: WO
Inventors: Graziano Vignali; Maurizio Mangani; Iuri Bernardi; Andrea Malatto
Original assignee: Graziano Vignali; Maurizio Mangani; Bernardi Luri; Andrea Malatto
Priority date: 2006-05-02
Filing date: 2006-05-02
Publication date: 2007-11-08
Also published as: WO2007125555A8

Abstract

A device (1) for controlling and managing the viscosity and density of a fluid (2), comprising a vessel (3) provided with an outlet (4) and with a second overflow port (5) at a preset level (6), a circuit (8) for drawing fluid (2) from a reservoir (7) and for introducing the fluid into the vessel (3). The device (1) comprises a weighing unit (17), on which the vessel (3) rests, an element for detecting the percolation time of the fluid (2) through the outlet (4) between an upper level (6) and a preset lower level, a computer (19) for controlling the device (1) which is interconnected to all the components, and at least one dispenser (22, 23) of a suitable top-up fluid. The top-up fluid can be dispensed within the fluid (2) to be controlled following measurements differing from the predefined values of the variation of the weight of the fluid (2) discharged in a constant percolation time and of the percolation time interval required to discharge an amount of fluid having a constant weight.

Description

DEVICE FOR CONTROLLING AND MANAGING THE VISCOSITY AND DENSITY OF A FLUID Technical field

The present invention relates to a device for controlling and managing the viscosity and density of a fluid. Background art

In all industrial processes using fluids of various kinds, it may be necessary to maintain the physical characteristics of said fluids, in particular their density and viscosity, within certain ranges of values in order to ensure the stability of their behavior.

Density: in the case of solutions (in which a solute is present within a solvent), the solvent may be particularly volatile and therefore its continuous evaporation entails a rapid variation of the composition of the solution. It is clear that such a variation may entail a change to the chemical and physical characteristics of the solution and make it unsuitable to maintain a constant and/or acceptable result. For example, a soluble salt at different concentrations may still be suitable for screen printing, but the result will be different depending on the corresponding concentration and therefore cannot be constant.

Further, if one considers that industrial processes often occur at high temperatures, evaporation of the solvents becomes a fundamentally important parameter.

Viscosity: this parameter is fundamental for controlling highly automated industrial processes. For example, in printing, if the ink changes viscosity, there may be an excessive deposition, which alters the drying process, creating sticky regions which would prevent the subsequent storage of the printed articles. It is extremely common to alter the viscosity of fluids in order to be able to automate processes or change performance, or in order to change the aesthetic or organoleptic appearance; for example, printing inks are thickened in order to prevent excessive spread, which would reduce definition: paints for wall surfaces are thickened in order to prevent dripping during application; sauces are thickened in order to give the sensation of consistency to the taste; shampoos are thickened in order to give the sensation of consistency to the touch and improve aesthetic appearance, et cetera. The term "viscosity" is of course used for the sake of simplicity, since the various aspects of rheology, viscosity, viscoelasticity, shear rate, thixotropy, et cetera should be considered. To simplify, one can divide fluids with modified rheology into two great groups: those thickened by adding organic thickening agents and those thickened by adding inorganic thickening agents or by adding insoluble fillers with a very fine particle size, generally below 50 microns, preferably below 20 microns. In the first case, carboxymethylcelluloses (CMCs), modified CMCs, alginates, natural rubbers, starches, annealed starches, modified starches, sugar fermentation products, dextrose, et cetera are used as organic thickening agents; in this case, the problem may occur of an increase in viscosity over time due to: a) the continuous recirculation of the fluid, which gradually improves the dispersion of the thickening agent; b) the variable characteristics of the thickening agent, which is usually of natural origin; c) possible reactions of components of the fluid with the thickening agent. In the second case, clays, modified clays, bentones, modified bentones, modified silicas with controlled particle size, phyllosilicates, et cetera, are used as inorganic thickening agents. In this case it is possible to have increases in viscosity due to: a) gradual improvement of the dispersion of the thickening agent due to continuous recirculation and continuous agitation; b) gradual decrease in particle size due to friction among the solid particles or between said particles and the moving mechanical elements.

There are some embodiments which are intended to control the characteristics of a fluid in order to maintain the concentration (and accordingly the viscosity and, in certain cases, also the density) within preset values.

First of all, it is possible to resort to actual manual measurements. The withdrawal of a unit of fluid and its subsequent measurement (weighing, rate of outflow through calibrated nozzles) allow to determine the viscosity and act on the fluid (for example by introducing additional solvent) in order to restore the base values if changes have occurred.

The precision of this type of control is entrusted to the skill of the person who performs it and entails considerable costs linked to the constant presence of said person: a machine that requires the constant checking of the chemical and physical characteristics of a fluid with which it works requires the presence of specialized personnel throughout its operation, with a consequent increase in operating costs.

There are solutions which are aimed at checking in a substantially automatic manner the viscosity of a fluid. Among these, it is worth mentioning the embodiment disclosed in Italian patent application MI94A002479, filed on 7 December 1994 in the name of Selectra S.r.l.

This document discloses a device which is adapted to check the viscosity of a liquid: a container which has a calibrated nozzle on its bottom is provided with elements for introducing liquid therein and with discharge means which prevent its excessive filling. The presence of the calibrated nozzle allows to measure the outflow time of the liquid between the overflow level and the level determined by the tip of an appropriately provided probe. If the time required for the outflow of a liquid having a correct viscosity is known, it is obvious that longer outflow times correspond to a more viscous fluid and vice versa.

In this case, if a controlled solvent dispenser is available, it is possible to introduce solvent in the liquid when the viscosity is too high.

If the viscosity is lower than the optimum level, however, it is not possible to intervene. The described instrument operates on the basis of the detection of the percolation time between the overflow level and the level constituted by the tip of a capacitive rod; if the liquid is sufficiently viscous and watery, a droplet can remain on the rod, altering the level to be measured and therefore altering the detection of the percolation time.

Moreover, such device does not allow to detect another parameter which is fundamental for the precise definition of all the chemical and physical characteristics that can affect the industrial process in which the fluid will be used, i.e., density.

To detect density it is instead necessary to weigh a unit of volume of fluid: currently, this check is possible by means of a load cell which is surmounted by a vessel having a known volume.

The problem linked to this type of detection is mainly the difficulty of automating the checks: since it is not possible to renounce the supervision of the density detector by trained personnel, the operating costs of the system increase. Another embodiment, disclosed in patent application

US2003/0046986, filed on 13 March 2003 in the name of Herman Herod, also provides for detection of the weight of a certain volume of substance in combination with the measurement of the percolation time of said substance through an opening of preset size. This solution has substantially two significant problems: first of all, the percolation of the liquid through the opening depends highly on hydrostatic pressure. In practice, when the container is almost empty, the pressure with which the liquid tends to flow out is extremely low, and for this reason its speed may be determined incorrectly. Further, since the liquid involved is often constituted by a suspension, any sediment on the bottom of the container can slow the percolation and/or partially obstruct the opening.

Secondly, in order to ensure effective detection of the weight of the preset volume of liquid it is convenient to perform continuous washes

(between one filling with liquid and the next of the container) in order to remove the sediment which would otherwise alter the test. It should also be noted that the choice of a rod arranged along the container immersed in the fluid contained for checking the levels inside said container entails numerous problems of inaccuracy: the detection is compromised by phenomena linked to the retention (adhesion) of the fluid or of some components thereof on the rod and to an obvious delay in measurements during the emptying of the container, in this case also due to the temporary adhesion of the fluid to the rod (the fluid along the rod flows out more slowly than the remaining fluid). Disclosure of the invention The aim of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid with automatic operation.

Within this aim, an object of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid which allows to intervene in order to vary these parameters even independently of each other.

Another object of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid which has a behavior that is substantially independent of the hydrostatic pressure of the column of fluid on which the tests are to be performed. Another object of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid which is independent of any deposits of sediment.

A further object of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid in which the level measurements are instantaneous and independent of adhesion of the fluid to the container and/or other parts of the device.

A still further object of the present invention is to provide a device for controlling and managing the viscosity and density of a fluid which has low costs and is relatively simple to provide in practice and safe in application. This aim and these and other objects, which will become better 303

6 apparent hereinafter, are achieved by the present device for controlling and managing the viscosity and density of a fluid, of the type comprising a vessel provided with an outlet and with an overflow port at a preset upper level, a circuit for drawing fluid from a reservoir and for introducing said fluid into said vessel, characterized in that it comprises a weighing unit on which said vessel rests, an element for detecting the percolation time of said fluid through said outlet between an upper level and a preset lower level, a computer for controlling said device which is interconnected to all the components, and at least one dispenser of a top-up fluid, said top-up fluid being dispensable within the fluid to be controlled following measurements differing from predefined values of the variation of the weight of the fluid discharged in a constant percolation time and of the percolation time interval required to discharge an amount of fluid having a constant weight. Brief description of the drawings Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of a device for controlling and managing the viscosity and density of a fluid, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a schematic view of a portion of an apparatus provided with a first embodiment of a device for controlling and managing the viscosity and density of a fluid according to the invention;

Figure 2 is a schematic view of a portion of an apparatus provided with a second embodiment of a device for controlling and managing the viscosity and density of a fluid according to the invention;

Figure 3 is a schematic view of a portion of a system provided with a third embodiment of a device for controlling and managing the viscosity and density of a fluid according to the invention. Ways of carrying out the invention With reference to the figures, the reference numeral 1 designates a device for controlling and managing the viscosity and density of a fluid 2.

The device 1 comprises a vessel 3, which is provided with an outlet 4 which supports a detachable nozzle. Detachability is extremely useful in order to ensure the maximum versatility of the device 1: it is in fact possible to fit a nozzle that is suitable for the physical and chemical characteristics of the fluid 2. The diameter of the nozzle must in fact be large if it is necessary to analyze viscous fluids 2; as the viscosity decreases, it is instead convenient to reduce the diameter.

The vessel 3 also has a second overflow port 5 at a preset level 6. According to the embodiment shown in the figure, this is a substantially tubular vertical channel which is connected directly to the bottom of the vessel 3. The overflow level 6 represents the maximum volume of fluid 2 that is present (in steady-state conditions) within the vessel 3: this volume is constant. When the free surface of the fluid 2 exceeds the level 6, said fluid enters from the inlet of the channel and falls into a reservoir 7 provided to contain all the fluid 2.

The reservoir 7 has an agitator 7a, which is driven by a respective motor 7b; the fluids 2 that can be contained tend to deposit on the bottom of the reservoir 7 or to stratify; the presence of the agitator 7a ensures that these phenomena are avoided, maintaining maximum uniformity of the fluid 2 in the reservoir 7.

There is also a circuit 8 for drawing the fluid 2 from the reservoir 7 and for introducing said fluid into the vessel 3. The circuit 8 comprises a pump 9, in which a withdrawal duct 10 is connected to the reservoir 7 (in particular, said duct leads to the reservoir 7 through an appropriately provided passage on its lateral surface) and a delivery duct 11 leads to a shunt 12. The delivery flow-rate of the pump 9 is greater than the discharge flow-rate of the hole 4 and lower than the maximum flow-rate than can be discharged (and is discharged) through the hole 4 and the overflow port 5. In this manner, the vessel 3 is always full (excess fluid 2 which flows out of δ the overflow port 5) and excessive accumulations of fluid 2 within the vessel 3 cannot occur, confirming that the maximum level that can be reached by the free surface of the fluid 2 in the vessel 3 corresponds to the level of the overflow and that the volume of fluid 2 contained in the vessel 3 in steady-state conditions is constant.

The shunt 12, controlled electrically by a computer 19 (subsequently described in detail), has two stable operating configurations: a first stable configuration corresponds to the free connection between the delivery duct 11 and a first end branch 13 (which faces and is proximate to the overflow level of the vessel 3 and is intended to fill it) and a second stable configuration corresponds to the free connection between the delivery duct 11 and a second branch 14 (which faces and is proximate to the top of the reservoir 7 and is intended to return the fluid 2 into it).

According to a second embodiment shown in Figure 2, it is also possible to insert two sensors 15 and 16 (which correspond to an upper level and a lower level), which can be substantially of any kind: they may be based on electrical conduction phenomena and may be photodetectors (and/or generic optical devices) without this affecting and/or modifying the behavior of the device 1 as a whole. The device 1 comprises a weighing unit 17, on which the vessel 3 rests. According to the embodiment shown in the figure, the weighing unit 17 is a load cell. In this case, it can be seen that the vessel 3 lies above the reservoir 7 and is supported by an appropriately provided arm 18; the load cell is interposed between the top of the arm 18 and the bottom of the vessel 3. Other embodiments, in which the weighing unit is subjected to the entire weight of the vessel 3 (and of the fluid 2 contained therein), are of course exactly equivalent.

For optimum operation, and in order to utilize in the best possible way the precision of the cell 17, it is convenient for the supporting arm 18 to rest directly on the ground (movable support or fixed interlocking) and to be physically separate (no point of contact) with respect to the reservoir 7. The reservoir 7 in fact comprises the agitator 7a and the pump 9 (besides the circuits for drawing the fluid 2 in order to supply it to the work line with which the device 1 is associated, as well as its return) and therefore vibrates even quite conspicuously. These vibrations might be transmitted to the arm 18, causing the measurements made by the cell 17 to be imprecise.

Even if suitable (and highly sophisticated) damping elements were interposed between the arm 18 and the reservoir 7 to mutually connect them directly, it would still be difficult to avoid any resonance phenomena which might occur when particular speeds of the agitator 7a are set (possibly in combination with the conditions set for the other dynamic components).

The device 1 is also provided with an element for detecting the percolation time of the fluid 2 through the outlet 4. In particular, the intermediate time is determined, during percolation, starting from the condition in which the free surface of the fluid 2 coincides with the level 6 to a limit condition which depends on the process set within a suitable computer 19 (for example up to a second level determined by a weight loss of interest set in the computer 19).

The fluid 2, inside the vessel 3, has as its upper limit the overflow level 6, which corresponds to the maximum volume and accordingly to the maximum weight (which can vary, since its depends on density) and has, as its lower limit, the level that corresponds to one of the following parameters, which can be preset or set:

- predefined percolation time: in this case, the instrument checks the discharged weight and corrects if the discharged weight is lower than the weight detected at the beginning of the procedure and confirmed;

— weight of the discharged material: in this case, the instrument checks the percolation time and corrects if the set time is exceeded.

According to the embodiment shown in Figure 2, the intermediate time detected during percolation corresponds to the intermediate time between when the free surface of the fluid 2 reaches the levels that correspond to the upper sensor 15 and the lower sensor 16. As an alternative, it is possible to consider as the upper level the overflow level 6 and to use a sensor (equally the sensor 15 or 16) only as the lower level (in this case it is possible to arrange even just one sensor in the vessel 3).

The device 1 also comprises a computer 19, which is interconnected to all the components; in practice, this may be a dedicated apparatus or a true computer, possibly interfaced with a plurality of devices 1 which are present on the work line. The computer 19 controls respective electric valves 20 and 21 (or other devices for controlling an opening which are substantially equivalent thereto), arranged at corresponding ports of two dispensers 22 and 23, which contain suitable top-up fluids which flow in respective loading ducts 24 and 25. Said top-up fluids therefore can be dispensed into the fluid 2 that is present in the reservoir 7 when, after performing suitable measurements (for example weight, percolation time, et cetera), it is found that the characteristics of the fluid 2 in the reservoir 7 differ from predefined values.

In particular, the dispenser 22 contains a solvent for diluting the fluid 2 to be controlled (in particular, if the fluid 2 is constituted by a water-based solution, a suitable solvent 24 might be water), useful in order to correct density increases; the dispenser 23 contains a fluid which is similar to the fluid to be controlled, with a viscosity value which is adapted to correct the increases in viscosity that can occur during the industrial process. Many industrial processes require liquids with increased viscosity

(liquids with modified rheology); for example, printing uses liquids with these characteristics in order to avoid percolations or diffusions which would reduce definition. The viscosity of these liquids must be kept constant in order to allow a reproducible and highly productive application. In order to do this, the device 1, in the dispenser 23, contains a fluid whose rheologic properties have not been altered; in most cases, this corresponds to the fluid 2 without the addition of thickening agents or, in the case of suspensions, to the fluid 2 without the solid part; when viscosity is found to have increased beyond the set interval, the fluid is added in order to return the viscosity within the correct interval. The addition of solvent related to the dispenser 22 within the fluid 2 entails a reduction in its density. The dilution of the fluid 2 that is present in the reservoir 7 with the fluid related to the dispenser 23 (which is similar to it but has predefined chemical and physical parameters) allows to optimize the value of viscosity. It is important to note that the outlet 4 comprises fixing means for a series of nozzles having a predefined diameter; in practice, it is therefore possible to replace the nozzle when the fluid 2 to be controlled changes. In this manner, the device 1 ensures maximum versatility, since it can operate with fluids which are particularly viscous by using large-diameter nozzles and vice versa.

Positively, the computer 19 has some series of terminals for interconnection to the dispensers 22 and 23 (in particular to their electric valves 20 and 21), to the shunt 12 and to the load cell 17 of a same device 1. At the same time, a same computer has a plurality of stages 19a₅ 19b, 19c, 19d (of course they might also be in a different number depending on the requirements of the application) in order to be associated with a plurality of devices 1, each connected by means of the respective series of terminals: in this manner it is possible to manage with a same computer 19 all the devices 1 that work on a same work line, minimizing dimensions and optimizing production cycles.

The present invention utilizes the processes for measuring viscosity by measuring the percolation time of a volume, and accordingly of a known weight by means of a calibrated port; likewise, and as an alternative, it is possible to measure the volume, and therefore the weight, which has flowed over a constant time period. Of course, the same acquired data, without applying the formulas that lead to viscosity, are themselves indexes of viscosity: for example, if 120 g flow in 10 seconds and then 100 g flow, this means that viscosity has increased; likewise, if 100 g flow in 10 seconds and subsequently flow in 12 seconds, this means that viscosity has increased.

The method of operation of the device 1 entails, as a first preliminary operation, starting the computer 19, setting the data related to the ideal conditions of the fluid 2 during use, and the intervals within which these data can vary without compromising the operation of the work line on which one or more devices 1 are installed.

The following procedure describes a method which, as an alternative- to the manual input of the necessary parameters, allows to detect and enter automatically in the device 1 the parameters of the fluid 2 during the step for preparing the device 1. The cycle of operations entails arranging the shunt 12 in the first stable configuration (the one that corresponds to the free connection between the delivery duct 11 and the first end branch 13, while the second branch 14 is isolated, in order to fill the vessel 3 with the fluid 2 drawn from the reservoir 7 with the pump 9). Operated by the computer 19, the weighing unit (according to the embodiment shown in the figure, the load cell 17) can determine the weight of the fluid 2 in the vessel 3 and send this data item to the computer 19.

At this point, the computer 19, if the volume of the vessel 3 and the detected weight are known, can determine the value of the density and assume it as the reference value (if it is certain that in this initial condition the fluid 2 has exactly the chemical and physical characteristics of interest). It is therefore up to the operator to choose an operating interval.

During steady-state operation, if the detected density is higher than the preset interval, the computer 19 activates, for a short predefined time, the first dispenser 22 (opening of the electric valve 20), which contains the solvent for diluting the fluid 2.

After the dilution of the fluid 2 in the reservoir 7, the cycle of operations is repeated in order to perform a new check of the data that arrive from the load cell 17. If, in a set time interval (which can be modified according to the requirements of the user and of the system that controls the device 1), the density has not returned within the interval predefined within the computer 19, the dispenser 22 is activated again (the corresponding electric valve opens). This action is repeated until the density falls again within the set interval. Going back to the moment when operation commences, once the density has been determined, it is necessary to arrange the shunt 12 in the second stable configuration (the one that corresponds to free connection between the delivery duct 11 and the second branch 14, while the first branch 13 is isolated, as can be seen in Figure 1). The interruption of the filling of the vessel 3 causes a continuous reduction of the level of the free surface of the fluid 2 within the vessel 3 due to percolation through the outlet 4; detection of the percolation time is activated automatically starting from the level 6 until the instant chosen by the operator, which corresponds to the emptying of approximately 2/3 of the vessel 3 (according to a preferred but not exclusive embodiment); the load cell 17 detects a reduction in overall weight caused by the discharged fluid 2 (through the opening 4).

Advantageously, in this manner the detection of the intermediate time is affected to a reduced extent by the variation of the hydrostatic pressure (of the column of fluid 2 within the vessel 3) caused by the emptying of the vessel 3.

The computer can monitor the weight as a function of a fixed time or can monitor the time as a function of a fixed weight. In the first case, it records a weight which it assumes as reference; in the second case, it records a time which it assumes as reference in this case also. The allowed deviation is set both if time recording has been chosen or weight recording has been chosen. In the steady-state operation, if the time is longer or the weight is lower than the preset interval, the computer 19 activates, for a predefined short time, the electric valve 21 of the vessel 23 that contains the fluid 2 at its minimum viscosity.

After the addition of the fluid 2 at minimum viscosity in the reservoir 7, the program continues to monitor the data that arrive from the load cell: if, within a preset (and modifiable) time period the weight or time has not returned within the set interval, the computer 19 again activates the electric valve 21, and the action is repeated until the weight or time is again within the set interval.

The method can of course be set to perform the checks described above alternately and at time intervals which can vary at will: obviously, intervals comprised in a range from few seconds to a few minutes are preferable.

For correct operation of the entire work line, the described method must be repeated continuously in order to ensure that the ideal conditions of the fluid 2 within the reservoir 7 are maintained.

The computer 19 is connected to a plurality of vessels 3, each of which is provided with dispensers 22 and 23 and with weighing units 17: in practice, a single computer 19 can control the execution of processes similar to the one described, whether simultaneous or staggered, in order to optimize the operation of the work line on which said computer is provided.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

For example, the delivery duct 11 can lack the shunt 12; in this case, the duct 11 is controlled by a driven valve 26, which is capable of interrupting the flow of the fluid 2 through the duct 11. Therefore, when one wishes to suspend the input of fluid into the vessel 3, the valve 26 is 0303

15 activated (this is a normally-open valve, which assumes the closed condition at an appropriate signal received from the computer 19).

Conveniently, the reservoir 7 can be fitted with at least one level sensor (for example, there might also be two sensors in order to define a maximum level and a minimum level): if the level of the fluid 2 in the reservoir 7 drops below a limit value, a hydraulic circuit is provided which is capable of drawing from an appropriate storage reservoir the fluid 2 in the initial conditions (therefore not thickened and/or modified during work cycles) and of introducing it in a desired amount into the reservoir 7. Conveniently, it is also possible to provide a sensor for detecting the temperature of the fluid 2 in the reservoir 7, since many fluids 2 can undergo variations in density and/or viscosity following temperature variations.

It is noted that by using specific sensors (for example infrared sensors) it is possible, by means of a single component, to check both the level and the temperature.

Further level sensors might also be arranged at the dispensers 22 and 23 (in particular in the containers of the respective fluids), in order to avoid the emptying of said containers and/or identify the correct operation of the device 1 (by having a visual indication of the reduction of the level of fluid in the containers associated with the dispensers 22 and 23).

An interesting criterion for application may relate to the management method (software), which must provide an alarm indicator to be activated whenever, after a certain number of successive correction cycles, the device 1 has been unable to restore the set values in the fluid that is present in the reservoir 7. This is advantageous in view of the fact that in this case the operator can analyze all the components in order to determine any problems that prevent correct operation.

As regards the reservoir 7, it should be noted that the motor 7b associated with the agitator 7a can have an adjustable speed, in particular, if it is an asynchronous motor, it is controlled by means of an inverter. The mixing rate influences greatly the characteristics of the fluid 2 and therefore the operator must set the speed value that is most suitable for the type of fluid 2 being used. The reservoir 7 can be thermally insulated by means of a layer of insulating material arranged outside it or by means of an execution which provides a chamber in which vacuum is provided between an internal wall (in contact with the fluid 2) and an external wall (in practice as occurs in so- called thermos flasks). For more complex embodiments, it is possible to provide a circuit for the circulation of a fluid at controlled temperature, which strikes the surface of the reservoir 7 in order to ensure maximum stability of the temperature of the fluid 2 inside it.

Finally, it should be noted that it is convenient (from a fundamental constructive point of view) to provide for the insertion of at least one filter in the circuits along which the fluid 2 flows. In particular, it should be noted that the fluid 2 (after being partially used) returns from the work line and is returned into the reservoir 7; in this case it is fundamental to arrange, along the return circuit, a suitable filter which eliminates any trace of processing residues.

It is conceptually correct to provide each duct of the device 1 with a respective filtering element along its extension, in order to prevent unwanted particles or clots formed within the fluid 2 from causing the measurements, and accordingly the adjustment, to be inaccurate. All the details may further be replaced with other technically equivalent ones.

In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments. Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.

In practice, the materials used, as well as the shapes and the dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.

Claims

1. A device for controlling and managing the viscosity and density of a fluid (2), of the type comprising a vessel (3) provided with an outlet (4) and with an overflow port (5) at a preset upper level (6), a circuit (8) for drawing fluid (2) from a reservoir (7) and for introducing said fluid into said vessel (3), characterized in that it comprises a weighing unit (17) on which said vessel (3) rests, an element for detecting the percolation time of the fluid (2) through said outlet (4) between the upper level (6) and a preset lower level, a computer (19) for controlling said device (1) which is interconnected to all the components, and at least one dispenser (22, 23) of a suitable top-up fluid, said top-up fluid being dispensable within the fluid (2) to be controlled following measurements differing from predefined values of the variation of the weight of the fluid (2) discharged in a constant percolation time and of the percolation time interval required to discharge an amount of fluid having a constant weight.

2. The device according to claim 1, characterized in that said weighing unit (17) is a load cell and said vessel (3) lies above the reservoir (7) for containing all the fluid (2), said vessel (3) being supported by a suitable arm (18), said cell (17) being interposed between the top of said arm (18) and said vessel (3).

3. The device according to claim 1, characterized in that said element for detecting the percolation time is active between the instant when the input of fluid (2) into said vessel (3) on the part of said input circuit ceases to the instant when said weighing unit detects a decrease in total weight equal to a preset value, which corresponds to the percolation of a predefined quantity of fluid (2).

4. The device according to claim 1, characterized in that said element for detecting the percolation time is active between the instant when the introduction of fluid (2) ceases for a constant time and records the weight reduction in said vessel (3).

5. The device according to claim 1, characterized in that said outlet (4) comprises fixing means for at least one nozzle having a predefined diameter, said diameter being set by the chemical and physical characteristics of the fluid (2) that will have to flow through it.

6. The device according to claim 2, characterized in that said nozzles are interchangeable in order to adapt said device (1) to the type of fluid (2) to be controlled.

7. The device according to one or more of the preceding claims, characterized in that said top-up fluid dispensers (22, 23) comprise a first dispenser (22), which contains a dilution solvent, which is conveyed into the reservoir (7) by the duct (24)-of the fluid (2) to be controlled, and a second dispenser (23) which contains a fluid which is similar to the fluid to be controlled with predefined viscosity, which is conveyed into the reservoir (7) by the duct (25).

8. The device according to one or more of the preceding claims, characterized in that it comprises a pump (9), which is controlled by said computer (19) and in which the withdrawal duct (10) is connected to the reservoir (7) of said fluid (2) and the delivery duct (11) is connected, by means of a first end branch (13) thereof, to the top of said vessel (3).

9. The device according to claim 8, characterized in that said delivery duct (11) of said pump (9) comprises a shunt (12), which is controlled by said computer (19), and a second branch (14) of a duct for returning the fluid (2) into the reservoir (7), said shunt (12) having a first stable configuration for free connection between the delivery duct (11) and said first end branch (13) and for isolation of said second branch (14), and a second stable configuration for free connection between the delivery duct (11) and said second branch (14) and for isolation of said first end branch (13).

10. The device according to one or more of the preceding claims, characterized in that said dispensers (22, 23) comprise valves which are controlled by said computer (19) and are intended to open and close the outflow port of the respective fluids.

11. The device according to one or more of the preceding claims, characterized in that said computer (19) has at least one series of terminals for connection to said dispensers (22, 23), said shunt (12), said load cell (17) of a same device (1), each of said series of terminals being associated with the components of a respective device (1).

12. The device according to one or more of the preceding claims, characterized in that it comprises at least one level sensor (15, 16) for the fluid (2) within said vessel (3), said at least one sensor (15, 16) being arranged at a level and being intended to determine the instant of the activation and deactivation of the element for detecting the percolation time following the alignment of the free surface of the fluid (2) in the vessel with the level that corresponds to it.

13. A method for the operation of the device (1) according to one or more of the preceding claims, comprising the steps of, while the computer (19) is activated:

- arranging said shunt (12) in said first stable configuration for free connection between the delivery duct (11) and said first end branch (13) and for isolation of said second branch (14) for filling said vessel (3) with said fluid (2) drawn from the reservoir (7) with said pump (9);

- in stable conditions of the fluid (2), by means of said weighing unit (17), determining the weight of the fluid (2) in the vessel (3) and sending said data item to said computer (19);

- the computer (19), once the volume of the vessel (3) and the detected weight are known, determining the value of the density, defining a first reference value;

- by means of said weighing unit (17), determining the weight of the fluid (2) in the vessel (3) and sending said data item to said computer (19) cyclically, for comparison with the reference value;

- if the detected density is higher than a preset value, activating, for a short predefined time, the first dispenser (22), which contains the solvent for diluting the fluid (2) to be controlled, and -repeating said weighing operations and optional dilution until the reference value is reached;

— arranging said shunt (12) in said second stable configuration for free connection between the delivery duct (11) and the second branch (14) and for isolation of the first end branch (13), and, at said instant, activating the element for detecting the percolation time through the opening (4);

- determining the intermediate time between said activation instant and the deactivation instant that corresponds to the detection, by the weighing unit (17), of a weight reduction equal to a preset value;

— the computer (19), since said intermediate time is known because the weight of the fluid (2) that is discharged is a predefined constant, determining the viscosity value;

— if the detected viscosity is higher than a preset value, activating, for a predefined short time, the second dispenser (23) which contains the fluid at minimum viscosity;

- topping up the vessel (3) and again determining said intermediate time and the corresponding viscosity value and activating said second dispenser (23) if the viscosity is again higher than the predefined value and repeating these operations until the predefined viscosity is reached.

14. The method according to claim 13, characterized in that it is repeated continuously in order to ensure that the preset/predetermined conditions of the fluid (2) are maintained.

15. The method according to claim 14, characterized in that the operations related to the measurement and control of viscosity are dependent on the preliminary adjustment of density.

16. The method according to claim 13, characterized in that said computer (19) is connected to a plurality of vessels (3), each of which is provided with respective dispensers (22, 23) and weighing units (17).

17. The method according to claim 13, characterized in that filling occurs without interruptions, the excess fluid (2) being expelled by means of said second overflow port (5).

18. The method according to claim 12, characterized by control of the weight discharged in a constant time interval.