RHEOMETER DEVICE WITH MINIMAL MEASUREMENT LOSSES, IN-LINE, IN MORE THAN ONE CAPILLARY SIMULTANEOUSLY, FOR SUSPENSIONS AND ITS METHOD OF OPERATION.

Abstract

The proposed development is a rheometer device that simultaneously measures viscosity (μ) and yield strength (to) online, with measurements taken at intervals of a few minutes for mining slurries. Therefore, the design must withstand the typical conditions of a mining operation (extreme temperatures, high altitude, communication problems, distance, extreme humidity, theft, mishandling, etc.). The rheometer in this development is based on the laminar flow transport of the slurry through capillaries. This rheometer measures simultaneously in more than one capillary. The online measurement and data analysis system accounts for the effects of sedimentation, capillary or pipe wall effects, temporal effects (e.g., thixotropy and viscoelasticity), and capillary inlet effects.On the other hand, it considers losses due to changes in diameter, the oscillatory effects of the point generated by the peristaltic pump, and the overreactions generated when the speed changes. A method for operating the rheometer device is also presented.

Description

RHEOMETER DEVICE WITH MINIMAL MEASUREMENT LOSSES, IN-LINE, IN MORE THAN ONE CAPILLARY SIMULTANEOUSLY, FOR SUSPENSIONS AND ITS METHOD OF OPERATION DESCRIPTIVE MEMORANDUM SCOPE OF APPLICATION OF THE DEVELOPMENT This development is presented in the field of measuring the physical parameters of fluids, specifically a rheometer for measuring rheological parameters, primarily for the mining industry. This development represents a substantial improvement over a previous design, reducing measurement time, improving accuracy, decreasing the overall size of the equipment, and enabling simultaneous measurements in more than one capillary. DESCRIPTION OF PREVIOUS ART The closest state-of-the-art rheometer design by the same inventor, CL 30192012, described in Figure 1, consists of a positive displacement pump connected to a manifold. This manifold feeds three vertical feed lines (capillaries) of varying diameters. The feed is applied alternately to each capillary; that is, the three are used separately and then one at a time. Six pressure gauges are installed in pairs on each of these three capillaries at three different heights. Three capillaries of different diameters are used to obtain a greater number of data points on a rheological curve that is constructed as measurements are taken. A density gauge and a flow meter are installed between the peristaltic pump and the manifold, before the pressure sensors are reached.Once the measurement in each capillary is complete, they are purged with a cleaning system (wash water) and drained to prevent the accumulation of particulate matter on the capillary walls. This procedure requires the installation of a flushing valve system, where water is injected to expel the fluid of interest using positive pressure. In each of the capillaries, the speed of the suspension is measured, and instruments such as sonar, ultrasonic (ultrasonic pulse mapping UPD and USV spectroscopy), nuclear magnetic resonance (NMR) and NMR imaging (NMR) can be used for this purpose. ι n Lnn / zznz / E / YiAi With the measured pressure data, plus the density and flow, the rheological parameters can be determined, from an analysis algorithm specially designed for the extraction of information and analysis that is described below. The development of the state of the art includes a system that controls the components of the rheometer, collects data and performs the processing of these, calculating the values ​​of the rheological variables and making the corrections due to the phenomena associated with complex suspensions (inlet effects, wall effects and temporal effects). The measured variables and the calculation of angular deformation rate (gamma point), wall stress, viscosity, and yield strength are performed by the microcontroller using dedicated software that controls the measurement duration, capillary cleaning, and the opening and closing of capillary valves. The data obtained will be stored in a historical database. This historical data can be analyzed using a dedicated platform. The server can be accessed from the operation's control room and by any user on the network. Measurements will be taken alternately in each capillary. Flow and density measurements will be continuous. Before starting operations, representative samples are taken for laboratory analysis of rheology, particle size distribution, or other parameters deemed relevant. As mentioned earlier, the proposed state-of-the-art rheometer and the information obtained by it work together with an analysis algorithm to ultimately obtain the viscosity and yield stress values. The analysis algorithm incorporates all the necessary corrections to eliminate parasitic effects. These effects will generally be calibrated depending on the suspension. Alternating measurements in the capillaries result in a longer time between measurements. On the other hand, measuring with a single capillary reduces the number of points for fitting the rheological curve and therefore produces greater uncertainty. Also described in the state of the art is patent CL 57664, from the University of Concepción, which shows a rheometer that avoids errors in the online measurement of the properties of complex mineral suspensions, which operates online to determine the properties of mineral suspensions with solid contents between 20-70%, and incorporates three ultrasonic Doppler flowmeters, a foot or microcontroller where the signals from the transmitters are received and processed; an HMI or Ethernet interface via a computer for displaying results; an ultrasonic Doppler flowmeter; a safety gauge pressure transmitter for the line; a flow pulse damper; a valve; a positive displacement pump that propels the pulp and is connected to the pulse damper; a pulp storage tank provided with agitation; and a pulp distribution tank from the process.and a pulp outlet that returns to the process; it also comprises three helical capillary tubes with their respective differential pressure sensors, through which pulp is continuously circulated at flow rates that vary over time, and the process for operating the rheometer is also presented. The previously mentioned patent differs from the rheometer of the present development in that it uses helical capillaries instead of straight ones, with the aim of reducing sedimentation problems. While this configuration avoids sedimentation problems, it introduces pressure losses that cause deviations in the pressure measurement, leading to increased errors in the rheological curve measurement and, consequently, in the measurement of the rheological parameters. On the other hand, there is also the rheometer described by the same inventor under patent number CL 51638, which features a device based on fluid transport in capillaries and a procedure for measuring rheological variables, including apparent viscosity and yield stress, for complex suspensions such as those found in mining. Specifically, it is a rheometer for measuring non-Newtonian fluids like mining suspensions, which also allows for online measurements and rapid results. The developed device is based on a multi-capillary arrangement, with online measurement of critical physical variables for the control and monitoring of the transport of a complex suspension. BRIEF DESCRIPTION OF THE DEVELOPMENT The proposed development corresponds to a rheometer device, described in Figures 2 and 3, which simultaneously measures viscosity (μ) and yield strength (τo) online, with measurements taken at intervals of a few minutes for mining slurries. Therefore, the design must withstand the typical conditions of a mining operation (extreme temperatures, high altitude, communication problems, distance, extreme humidity, theft, mishandling, etc.). The rheometer of this development is based on the laminar flow transport of the slurry through capillaries. This rheometer measures simultaneously in more than one capillary. The online measurement and data analysis system considers the effects of sedimentation, capillary or pipe wall effects, temporal effects (e.g., thixotropy and viscoelasticity), and capillary inlet effects (Z. JASTRZEBSKI).On the other hand, consider the losses due to changes in diameter, the oscillatory effects of the pulse generated by the peristaltic pump, and the overreactions generated when the speed is changed. DETAILED DESCRIPTION OF THE DEVELOPMENT It should be understood that the present development is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications described herein, as these may vary. It should also be understood that the terminology used herein is for the sole purpose of describing a particular representation and is not intended to limit the perspective and potential of the present development. It should be noted that the terms "use" and "method," here in the statement of claims and throughout the text, do not exclude the plural unless clearly implied by the context. Thus, for example, a reference to a "use or method" refers to one or more uses or methods and includes equivalents known to those skilled in the art. Similarly, as another example, a reference to "a step," "a stage," or "a mode" refers to one or more steps, stages, or modes and may include implicit and / or subsequent sub-steps, stages, or modes. All conjunctions used must be understood in their least restrictive and most inclusive sense. Thus, for example, the conjunction “or” should be understood in its orthodox logical sense, and not as an “exclusive or,” unless the context or text expressly requires or indicates otherwise. The structures, materials, and / or elements described should also be understood to refer to those that are functionally equivalent, thus avoiding endless, exhaustive lists. Expressions used to indicate approximations or conceptualizations should be understood as such, unless the context dictates a different interpretation. All technical and / or scientific names and terms used herein have the common meaning given to them by a person who is competent in these matters, unless otherwise expressly indicated. i? ι n Lnn / zznz / E / YiAi The methods, techniques, elements, compounds, and compositions are described, although methods, techniques, compounds, and compositions similar and / or equivalent to those described may be used or preferred in the practice and / or testing of the present invention. All patents and other publications are incorporated as references, for the purpose of describing and / or informing, for example, the methodologies described in said publications, which may be useful in relation to the present development. These publications are included only for their information prior to the filing date of this patent application. In this respect, nothing should be considered as an admission or acceptance, rejection or exclusion, that the authors and / or inventors are not legitimate to be so, or that said publications are predated by virtue of previous ones, or for any other reason. To bring clarity to this discussion, the following concepts will be defined: 1.- Mining suspensions: For the purposes of this development, mining suspensions are considered to be those heterogeneous mixtures of insoluble solid particles that are dispersed in a liquid, such as tailings or concentrates. 2. Rheometer: For the purposes of this development, a rheometer is considered an instrument for measuring how a fluid and / or suspension flows under the effect of an external force. These devices measure not only viscosity but also other parameters such as yield strength or elasticity. 3. Thixotropy: For the purposes of this discussion, thixotropy refers to a property of some non-Newtonian fluids where viscosity depends on time. Specifically, viscosity decreases with increasing shear stress. 4.- Viscoelasticity: For the purposes of this development, viscoelasticity refers to the behavior of some fluids that exhibit both viscous and elastic rheological behavior. 5.- Viscosity: For the purposes of this development, viscosity refers to the resistance of a fluid to shear stress. i? ι n Lnn / zznz / E / YiAi 6.- Yield stress: For the purposes of this development, yield stress refers to the shear stress that must be applied to a fluid for it to begin to flow. 7.- Parasitic effects: For the present development, parasitic effects refer to all pressure losses that appear during the transport of the pulp in the RMC, and that are not associated with the flow of the pulp in straight pipes, for example, valves, elbows, curves. 8.- Wall effects: For the present development, wall effects refer to a phenomenon observed in the transport of suspensions, where, due to shear, the concentration of particles decreases in the vicinity of the wall and, as a consequence, the condition of no wall slippage is not met, and therefore an increase in flow (volume / time) is observed. The ore pulp can originate from a pressurized pipe, trough, or tank. Using various sampler types and alternatives (1), a portion of this fluid is diverted to the rheometer. A positive displacement (8) (or peristaltic) pump, controlled by a frequency inverter, propels the pulp through a pipe to an oversize filter (3). This filter prevents particles of a size comparable to the pipe diameter from entering the system and clogging it (for example, if the capillary's internal diameter is 30 mm, a filter with a mesh size ten times smaller is used). Electrically instrumented pressure sensors (5a and 5b) with a measurement range appropriate for the installation and pulp are installed at both the inlet and outlet of this oversize filter to measure the pressure variation due to changes in the size of the solid material. This measurement is useful for the early detection of clay minerals. The positive displacement (or peristaltic) pump, by its operating principle, generates fluid pulses. This causes the flow rate and pressure to oscillate over time. Rheological measurement requires that each flow step be stable and constant. This is achieved with a pulse damper (9). Another effect that must be avoided is the overreaction of the flow rate when the pump speed is changed. This produces overreaction and a subsequent oscillation. This effect is mitigated with an electronic adaptive control loop between the flow measurement and the pump speed. i? ι n Lnn / zznz / E / YiAi A few meters downstream of the filter outlet pressure sensor (5b) (the distance will depend on the distance between the sampling point and the location of the capillaries), the flow sensor (6) is located, followed one meter further downstream by a velocity profile meter (10), and then (for example, one meter further downstream) by a fluid density sensor (7). These sensors can be installed vertically or horizontally. In the example of the configuration with 5 bends, all three sensors are installed vertically, and in the configuration with 2 bends, only the velocity profile meter (10) and the fluid density sensor (7) are installed vertically. The flow rates to be measured will depend on the diameters and lengths of the capillaries. For example, in installations with pipes (T1-T6) between 1 and 30 meters long (preferably 7 meters) and internal diameters between 100 mm and 10 mm (preferably D1 = 40 mm, D2 = 32 mm, and D3 = 26 mm), the flow rates to be measured would range from 1000 to 5000 l / h. Typically, the densities range from 1000 to 2000 kg / m³. Next, the capillaries are connected serially according to the description presented in Figure 2. Error! Reference source not found. In a typical configuration (Figure 2), the rheometer consists of three capillaries with different internal diameters, allowing the same equipment to measure pulp with both low and high rheology. When rheology is very high, shear banding instabilities appear at low strain rates, and a Bingham or Herschel and Bulkley rheogram cannot be constructed, according to P. Schall and M. Van Hecke (2010), "Shear Bands in Matter with Granularity," Ann Rev of Fluid Mech Vol. 42:67-88. Each of the capillaries (capillary 1, capillary 2, and capillary 3) has a different diameter (D1, D2, and D3, respectively). Capillary 1 is formed by two straight tubes (T1 and T2) with diameter D1 (it must be long enough to ensure that the flow is parallel to the tube's axis when the fluid passes through the pressure sensor (5b)). The flow goes up through pipe T1 and down through pipe T2.Both pipes are joined by a first U-shaped curved pipe (C1), with a bend diameter at least ten times the internal diameter of capillary 1, to minimize losses due to the bend. At the end of the pipe where the flow descends (T2), a pipe at least 20 centimeters long (4a) is attached, smoothly reducing the diameter from D1 to D2 along its length. Capillary 2 is connected to the end of the reduction (4a) of capillary 1 by means of a second U-shaped curved pipe (C2) with a diameter D2; the bend diameter is at least 10 times the internal diameter D2. A straight pipe of diameter D2 (T3, where the flow ascends) is connected to the second curved pipe (C2), which has the same internal diameter as capillary 2, and through which the flow... ι n Lnn / zznz / E / YiAi goes up again (the length of this pipe is equal to that of the tubes (T1 and T2) of Capillary 1).A second pipe of diameter D2 (T4, where the flow descends), of identical length to the first, is joined to the first by means of a third U-shaped curved pipe (C3), with the same internal bend diameter as C2. The flow descends through this pipe. A second reducer (4b) is joined to the end of the straight pipe T4, and over a distance of at least 20 cm, the diameter is smoothly reduced from diameter D2 to diameter D3. Capillary 3 is connected to the end of the reduction (4b) of capillary 2 by means of a fourth U-shaped curved pipe (C4) with a diameter D3 and an internal curvature diameter equal to C3. A straight pipe with a diameter D3 (T5, where the flow rises) is connected to the fourth curved pipe (C4), and the flow returns to the upwards through this pipe (the length of this pipe is equal to that of the pipes of Capillary 1 and Capillary 2). A second pipe with a diameter D3 (T6, where the flow falls), of the same length as the previous one, is connected to it by means of a fifth U-shaped curved pipe (C5) with the same internal curvature diameter as C4. The flow descends through this pipe. The end of this third capillary is connected to a pipe that carries the fluid back to the sampling point or another disposal site. The purpose of doubling the capillaries is to reduce the overall height of the device and thus lower the costs associated with the rheometer's structural stability. The capillaries are arranged vertically to prevent sedimentation and potential clogging. The piezometers (5c1,2), (5d1,2), (5e1,2), (5f1,2), and (5h1,2) are installed in such a way as to eliminate the effect of gravity on the mathematical model equations. At the midpoint of each capillary 1, 2, and 3, pressure sensors (5c1, 5d1, 5e1, 5f1, 5g1, 5h1) and redundant pressure sensors (5c2, 5d2, 5e2, 5f2, 5g2, 5h2), also called piezometers, are installed. The pressure measurement ranges will depend on the total length of the pipes (from the sampler to the sensors). Typically, these sensors must measure pressures up to 10 bar. However, the most important factor is that the instrument's accuracy be in the range of 1 to 100 mbar, preferably 10 mbar.In a second typical configuration (Figure 3), the rheometer consists of three capillaries with different internal diameters, allowing the same equipment to measure pulp with both low and high rheology. Each capillary (capillary 1, capillary 2, and capillary 3) has a different diameter (D1, D2, and D3, respectively). Capillary 1 is formed by a straight pipe (T1) with diameter D1 (it must be long enough to ensure the flow is parallel to the pipe's axis when the fluid passes through the pressure sensor (5b)). The flow rises in pipe T1. At the end of pipe T1, a pipe at least 20 centimeters long (4a) is attached, which smoothly reduces the diameter from D1 to D2 along its length.Capillary 2 is connected to the end of the reducer (4a) of capillary 1 by means of a U-shaped curved pipe (C1) with a diameter D2 and a bend diameter at least ten times the internal diameter of capillary 2, in order to minimize losses due to the bend. Capillary 2, with an internal diameter D2 (T2, where the flow decreases), is connected to a second reducer (4b) that smoothly reduces the diameter from D2 to D3 along that length. Capillary 3 (T3) is connected to the end of the reducer (4b) of capillary 2 by means of a U-shaped curved pipe (C2) with a diameter D3 and a length of at least 20 cm and a bend diameter at least ten times the internal diameter of capillary 3, in order to minimize losses due to the bend. The length of tubes (T2 and T3) can be the same length as Capillary 1. The end of this third capillary is joined to a pipe that carries the fluid back to the sampling point or another disposal site. The capillaries are arranged vertically to avoid the effects of sedimentation and possible blockages. Pressure sensors (5c1, 5d1, 5e1, 5f1, 5g1, 5h1) and redundant pressure sensors (5c2, 5d2, 5e2, 5f2, 5g2, 5h2), also called piezometers, are installed at the ends of each capillary 1, 2, and 3. The pressure measurement ranges will depend on the total length of the pipes (from the sampler to the sensors). Typically, these sensors must measure pressures up to 10 bar. However, the most important factor is that the instrument's accuracy be in the range of 1 to 100 mbar, preferably 10 mbar. In both configurations, the distance between the flow sensor (6) and the first capillary should not be less than one meter; for example, without restricting the device to this measurement, 20 meters, to ensure parallel flow in the capillary pressure measurement zone. The radius of curvature, greater than ten times the capillary diameter, also aims to prevent significant parasitic losses that could affect the rheology measurement. For the calculation of rheological parameters, as in patent CL51638, the transport of a fluid in laminar flow (Reynolds number Re < 2000, where ρ is the fluid density, D the pipe diameter, U the average velocity, and μ the fluid viscosity) in a circular tube is considered. In a measurement, the flow rate (Q) is varied in steps. Flow and pressure sensors record these variables. The apparent rheogram (γα) is constructed by measuring the pressure variation between pressure sensors (ΔP) located at a linear distance AL and the flow rate (Q). 32Q _ AP ​​DTw“ AL 4 Based on the rheological curve, the model is adjusted by providing the desired rheological parameters. Rheology measurement is based on measuring pulp density, velocity profile, flow rate, and pressure losses in the capillaries. These variables are measured with sensors. The accuracy of the measurement depends on the accuracy of these sensors (in this case: pressure, flow, velocity, and density sensors). Furthermore, due to the nature of the fluid and the design of the RMC (Respiratory Media Control) system, parasitic effects appear, such as: 1) wall effects, which cause inaccurate flow rate measurements, and 2) parasitic pressure losses caused by couplings, valves, manifolds, changes in diameter, curved pipe sections, elbows, etc. In both the initial and current designs, wall effects are reduced by avoiding smooth walls. Parasitic pressure losses due to welds, elbows, joints, and other fittings are unavoidable; however, they can be minimized. To avoid these effects, the section between pressure sensors must be free of such losses or at a sufficient distance (at least 10 diameters) to prevent this effect from impacting the pressure measurement. The loss associated with the curves (C1-C5), calculated from the model of SIGGERS, JH, & WATERS, SL (2005). Steady flows in pipes with finite curvature. Physics of Fluids, 17(7), 077102. doi: 10.1063 / 1.1955547, yields a deviation from a straight pipe of less than 0.1%. Therefore, this effect can be considered negligible. On the other hand, the losses associated with a helical configuration (S. LIU AND JH MASLIYAH (1993), “Axially invariant laminar flow in helical pipes with a finite pitch”, J. Fluid Mech. (1993), vol 251. pp. 315-353), with internal diameters identical to those of this proposal and a helix curvature radius of 20 cm, a free length of 2 m, can reach deviations of up to 20% (see patent with helical capillary arrangement CL 57664). i? ι n Lnn / zznz / E / YiAi To reduce losses associated with contractions, a length of 20 cm is chosen, so that losses are less than 0.01 (D. RENNELS and H. HUDSON (2012), “w. 1st edition”, Hoboken, NJ: Wiley, 2012). The capillary configuration of this design allows for simultaneous measurement in all three capillaries, reducing measurement time. This configuration also reduces water consumption and the need for flush valves (2), as capillary cleaning is not required between measurements. Cleaning is only performed when the system detects an abnormal operation due to solids buildup or other causes. Another advantage of this configuration is that, since the pressure sensors are at the same height, the weight of the column is eliminated from the equation. The effects of entry and exit are mitigated by considering that the measurement is carried out far from the entry and exit points of the capillary and by decreasing the number of valves, with respect to the patent of the same inventor CL51638. Wall effects, unavoidable in the transport of mining slurries, are corrected with appropriate wall models: Qrea¡=Q-QP Qp= n^Twgces the modification of the flow rate due to wall effects (JASTRZEBSKI, J. (1967), “Entrance Effects and Wall Effects in an Extrusion Rheometer During the Flow of Concentrated Suspensions”, l&EC Fundamentalis 6 (3), pp 445-454). The rheometer is operated by a control system. This system controls the valves and the pump. It also collects pressure measurements from the filter and capillaries. Finally, this system also calculates the rheology, considering non-Newtonian models such as Bingham, Herschel-Bulkley, or others. The control system communicates with the operating room via Ethernet or wireless connection, delivering rheology, density change and / or rheology data at intervals of a few minutes. The method for performing the measurement is as follows: i? m Lnn / zznz / E / YiAi a) Pre-selection of flow rates (controlled steps or ramps) and programmed to be selected on the displacement pump and with a duration of at least a few seconds. The selection of flow rates will depend on the previous data available on pulp density and rheology; b) Start of the flow rate ladder and in parallel recording of the flow rate measurements, the pressure from the sensors (5c1, 5d1, 5e1, 5f1, 5g1, 5h1, 5c2, 5d2, 5e2, 5f2, 5g2, 5h2), the velocity profile and the pulp density. (By means of the control system); c) Collection of measurement information by the control system and delivery as input data for the calculation of rheological parameters; d) Recording at every instant in real time: the flow rate, the pressure in each of the pressure sensors, the velocity profile and its flow rate; e) The control system discards the measurement if the data is insufficient or defective, and does not store it, instead providing the control system with a new set of flow rates. Conversely, if no error message is issued, the system stores the results and provides the rheology, pulp density, and oversize filter clogging data; f) Once the measurement is complete, and if no order has been received to change the range and flow rate steps to be measured, the RMC immediately begins to perform a new measurement; and g) The process of calculating rheology is as follows: I. For each instant in time, an array is generated with the collected information; II. Due to the imprecision of the sensors and other data recording problems, the data is cleaned by removing fields without data, pump overreaction, outliers, averaging, and standard deviation; i? ι n Lnn / zznz / E / YiAi III. The pressure difference between pressure sensors is calculated; IV. The apparent strain rate is calculated; V. With the cleaned data, the apparent rheology curve and velocity profile are generated; VI. The rheological parameters are calculated. In the case of the Bingham model: yield strength and Bingham viscosity. In the case of the Herschel-Bulkley model: yield strength, exponent, and consistency factor; VII. Pressure corrections are made for inlet and outlet effects and for wall slippage: limf , M>real =M>P -&Pe < L / R^O / Where APe is the pressure drop due to inlet effects, ΔP measured by pressure sensors; and VIII. The correction for wall effect is performed, using the velocity profile measurement. Qreal=Q-QP Qr is the modification of the flow rate due to wall effects; h) The data are displayed in trend curves, with alert criteria in cases of unexpected variations. i) The process is repeated automatically and constantly; and j) Statistical analysis of the control period (hours, shift, weeks, months, years) is performed. To perform the calibrations, the rheometer measurements are compared with laboratory instruments. Samples for laboratory measurement are taken in the sampler (1). The results of the measurements taken with the sample are manually entered into the system database, thus recording the calibration. As an option to the present development, and if the case is, where there is not enough space in the operating area, it is possible to compact the geometry of the present rheometer, as described in figure 3. In this configuration, the measurement is carried out in straight sections, so the weight of the column must be considered in the calculation of the head losses. Table I below shows a comparison between the number of valves, curves, and the losses associated with those curves of the present invention in its two alternatives and the devices described in the previously mentioned prior art: i? ι n Lnn / zznz / E / YiAi Table I Item CL 3019-2012 CL 57664 RMC (Fig.2) proposed 1 RMC (Fig.3) proposed 2 Capillary valves 3 3 0 0 Coil turns 0 5-20 0.5 0.5 Curves between pressure sensors for rheology measurement 0 5-20 1 0 Losses associated with the curves 0 up to 20% 0.10% 0 Table I shows that the coil's curves increase measurement error due to the coil's twists. Furthermore, the tubes must be made of stainless steel because they deform much less with temperature changes, especially considering that this system will operate in a mining operation where temperatures fluctuate daily and seasonally. Unlike the rheometer cited in patent CL 57664, which uses PVC tubes, this may reduce the system's cost but increases measurement error. DESCRIPTION OF FIGURES Figure 1: This figure presents the scheme of the state of the art closest to the present development in patent CL 51638. Figure 2: The present figure describes a first scheme of the configuration of the present development, where the numerals indicate: (1) Sampler (2) Wash water (3) Oversize filter (4) (4a) First reduction and (4b) Second reduction (5a) Pressure tap before the filter (5b) Pressure tap after the filter (5c1) Upflow pressure tap before the first reduction (5c2) Redundant upflow pressure tap before the first reduction (5d1) Downflow pressure tap before the first reduction (5d2) Redundant downflow pressure tap before the first reduction (5e1) Upflow pressure tap before the second reduction (5c2) Redundant upflow pressure tap before the second reduction (5f1) Downflow pressure tap before the second reduction (5f2) Redundant downflow pressure tap before the second reduction (5g1) Upflow pressure tap after the second reduction (5c2) Redundant upflow pressure tap after the second reduction (5h1)Downstream column pressure tap after the second reduction (5c2) Redundant downstream column pressure tap after the second reduction (6) Flow meter or flow sensor (7) Densimeter or fluid density sensor (8) Positive displacement pump ι n Lnn / zznz / E / YiAi (9) Pulse damper (10) Velocity profile meter T1 Ascending pipe of the first capillary T2 Downpipe of the first capillary T3 Ascending pipe of the second capillary T4 Downpipe of the second capillary T5 Third capillary riser pipe T6 Third capillary downpipe C1 First U-shaped curved pipe C2 Second U-shaped curved pipe C3 Third U-shaped curved pipe Fourth U-shaped curved pipe C5 Fifth U-shaped curved pipe D1 First internal diameter of the pipe D2 Second internal diameter of the pipe D3 Third internal diameter of the pipe On the other hand, the horizontal hourglass symbol (►◄) corresponds to different valves, which, with respect to the inlet or outlet arrow, which is indicated, implies the direction of liquid entering or leaving the device. Figure 3: The present figure describes a second scheme of the configuration of the present development, where the numerals indicate: (1) Sampler (2) Wash water (3) Oversize filter (4) (4a) First reduction and (4b) Second reduction (5a) Pressure tap before the filter (5b) Pressure tap after the filter (5c1) First upstream pressure tap before the first reduction (5c2) First redundant upstream pressure tap before the first reduction (5d1) Second upstream pressure tap before the first reduction (5d2) Second redundant upstream pressure tap before the first reduction (5e1) First downstream pressure tap before the second reduction (5c2) First redundant downstream pressure tap before the second reduction (5f1) Second downstream pressure tap before the second reduction (5f2) Second redundant downstream pressure tap before the second reduction (5g1) First upstream pressure tap after the second reduction(5c2) First redundant upstream pressure tap after the second reduction (5h1) Second upstream pressure tap after the second reduction (5c2) Second redundant upstream pressure tap after the second reduction (6) Flow meter or flow sensor (7) Density meter or fluid density sensor (8) Positive displacement pump (9) Pulse damper (10) Velocity profile meter T1 Ascending pipe of the first capillary T2 Downpipe of the second capillary T3 Third capillary ascending pipe C1 First U-shaped curved pipe Second U-shaped curved pipe D1 First internal diameter of the pipe D2 Second internal diameter of the pipe D3 Third internal diameter of pipe i? ι n Lnn / zznz / E / YiAi On the other hand, the horizontal hourglass symbol (►◄) corresponds to different valves, which, with respect to the inlet or outlet arrow, which is indicated, implies the direction of liquid entering or leaving the device. Figures 4a and 4b: Figure 4a shows a diagram with the raw data processed by the algorithm (ROM) of the shear stress of the rheogram of a suspension passing through the device via the three capillaries 1, 2 and 3. On the other hand, Figure 4b presents a diagram with the averages of the shear stress data of the passage of the suspension through the different capillaries 1, 2 and 3 obtained in Figure 4a. Figure 5: Figure 5 shows a graph where the filtered data obtained in Figure 4b are presented and an expected rheogram is compared with the laboratory data and the adjustment of the data to better approximate the actual response. Where, the solid line corresponds to the expected rheogram obtained in the laboratory, Where, the fitting method corresponds to a segmented line. Where, the filtered data coming from figure 4 corresponds to the spheres of the graph. APPLICATION EXAMPLE An experiment was conducted to verify the fluid dynamics over time during the operation of the rheometer, considering capillaries with diameters of: 3.81 cm (1 / 2 inch) SCH 40, 3.175 cm (1 / 2 inch) SCH 80, and 2.54 cm (1 inch) SCH 40. A flow ramp was used, as shown in Table II: Yo? ι η ίηη / ζζηζ / Ε / γίΛΐ Table II Q Ti (min) Tf (min) (l / h) 0 1 950 1 2 1,400 2 3 1,850 3 4 2,300 4 5 2,750 5 6 3,200 6 7 3,650 7 8 4,100 8 9 4,550 9 10 5,000 i? m Lnn / zznz / E / YiAi For data analysis, the Fluent algorithm is used in the following regime: Steady, laminar, with time step = 0.01. A Bingham fluid is considered: • tf— 34 Pa, με = 0.021 Pa s • Density: 1809 kg / m3 • Cp= 70% Noise is added to the measured pressures and flow rates to simulate mining operations. The resulting data is processed using the RMC algorithm, and the rheograms shown in Figures 4 and 5 are obtained. Figure 4a shows the rheogram with the raw data, and Figure 4b shows the average of the data. Figure 5 shows the filtered data (spheres), and the expected rheogram (obtained in the laboratory, solid line) is compared to a fitted rheogram (dashed line). The results show good agreement with the expected rheology, with the difference in yield strength being less than 5% in the best fit.

Claims

1. - Rheometer device for measuring viscosity (μ) and yield stress (το), with minimal measurement losses, in-line, in more than one capillary simultaneously, for suspensions, CHARACTERIZED in that it comprises the inlet to the rheometer device from a pressure pipe, channel or tank, by means of a sampler (1), where a positive displacement pump (8) propels the suspension through a pipe to an oversize filter (3), where said oversize filter (3), both at its inlet and outlet, pressure sensors (5a and 5b) are installed to measure the pressure variation, where the positive displacement pump (8) generates fluid pulses generating flow and pressure oscillations over time, which are controlled generating a stable and constant flow with a pulse damper (9), where downstream of the pressure sensor (5b), the flow sensor (6) is located,Further along, a velocity profile meter (10) and then a fluid density sensor (7), where the flow then passes through three capillaries connected in series with different internal diameters D1, D2 and D3, with two reductions in the capillary diameter (4a) and (4b) and with U-shaped curves connecting everything, with a control system and an algorithm to calculate the rheological parameters.

2. Rheometer device, according to claim 1, CHARACTERIZED in that the serially connected capillaries are formed, in a first configuration, by two straight pipes (T1, T2, T3, T4, T5 and T6) of different diameters (D1, D2 and D3), where piezometers (5c1,2), (5d1,2), (5e1,2), (5f1,2) (5g1,2) and (5h1,2) are located passing through these pipes respectively, where the flow rises through pipes T1, T3 and T5 and the flow falls through pipes T2, T4 and T6, where the pipes of the same capillary are joined through U-shaped bends (C1, C3 and C5), with a curvature diameter at least ten times the internal diameter of the capillary, where, at the end of each capillary, a pipe (4a) and (4b) are attached that smoothly reduces the diameter, from diameter D1 to a diameter D2 and then from diameter D2 to a diameter D3, where at the end of the reductions and to connect the different capillaries there are second U-shaped curved pipes (C2 and C4),where the bend diameter is at least 10 times the internal diameter, where at the end of the third capillary it is joined to a pipe that carries the fluid back to the sampler (1) or other disposal site.

3. - Rheometer device, according to claim 1, CHARACTERIZED in that the serially connected capillaries are formed, in a second configuration, by straight pipes (T1, T2 and T3) of different diameters (D1, D2 and D3), where the flow rises through pipes T1 and T3 and the flow falls through pipe T2, so the weight of the column must be considered in the calculation of the head losses, where also, passing through pipe T1 are the piezometers (5c1,2), (5d1,2), passing through pipe T2 are the piezometers (5e1,2), (5f1,2) and passing through pipe T3 are the piezometers (5g1,2), (5h1,2), where the pipe of one capillary is joined to another through U-shaped bends (C1 and C2), with a curvature diameter of at least ten times the diameter internal to the capillary, where, at the end of each capillary, a pipe (4a) and (4b) is attached that smoothly reduces the diameter, from diameter D1 to a diameter D2 and then from diameter D2 to a diameter D3,where at the end of the third capillary it joins a pipe that carries the fluid back to the sampler (1) or another disposal site.

4. Rheometer device, according to claim 1, CHARACTERIZED in that the U-shaped curves of capillaries C1 to C5 decrease the height of the total device installation and thus provide structural stability, in addition the capillaries are arranged vertically to prevent sedimentation and silting of the suspension, where in addition the piezometers (5c1,2), (5d1,2), (5e1,2), (5f 1,2) and (5h1,2) are installed in such a way as to eliminate the effect of gravity in the equations for calculating viscosity (μ) and yield stress (το).

5. Rheometer device, according to claim 1, CHARACTERIZED in that at half height of each capillary 1, 2 and 3, there are pressure sensors (5c1, 5d1, 5e1, 5f1, 5g1, 5h1) and redundant pressure sensors (5c2, 5d2, 5e2, 5f2, 5g2, 5h2), where the pressure measurement ranges will depend on the total length of the pipes from the sampler (1) to the pressure sensors (5c1,2, 5d1,2, 5e1,2, 5f1,2, 5g1,2, 5h1,2), where said sensors must measure pressures up to 10 bar, where the accuracy of the instrument is in the range of 1 to 100 mbar.

6. - Rheometer device, according to claim 1, CHARACTERIZED in that the algorithm in the data analysis considers the effects of sedimentation, the wall effects of the capillary or pipe, temporal thixotropic and viscoelastic effects and capillary entrance effects, where the measurement losses due to changes in diameter D1, D2 and D3, the oscillatory effects of the pulse generated by the peristaltic pump (8) and the overreactions generated when the flow rate is changed are also considered.

7. Method of operation of the rheometer device described in claim 1, CHARACTERIZED in that it comprises the steps of: i? m Lnn / zznz / E / YiAi a) Pre-selection of a series of flow rates and programming to be selected in the displacement pump (8), where the selection of the flow rates depends on the background information on the density of the suspension and rheology; b) Initiation of the flow rate ladder and recording of the measurement of the flow rates, the pressure of the sensors (5c1,2, 5d1,2, 5e1,2, 5f1,2, 5g1,2, 5h1,2), the velocity profile and the density of the suspension, through the control system; c) Collection of the measurement information by the control system and delivery as input data for the calculation of the theoretical parameters to the algorithm; d) Recording at each instant in real time: the flow rate, the pressure in each of the pressure sensors, the velocity profile and its flow rate;e) Elimination of measurements if the data is insufficient or defective by the control system, where they are not stored, and a new set of flow rates can be provided to the control system. f) Once the measurement is complete, and if no command has been received to change the range and flow rate steps to be measured, the rheometer device immediately begins to perform a new measurement; g) Application of the rheology calculation algorithm, where: I. For each instant in time, an array is generated with the collected information; II. Due to the imprecision of the sensors and other data recording problems, the data is cleaned: eliminating fields with no data, pump overreaction, outliers (atypical values), averaging, and calculating its standard deviation; III. The pressure difference between the pressure sensors is calculated; IV. The apparent strain rate is calculated;i? m Lnn / zznz / E / YiAi V. With the clean data from point II, the apparent rheology curve and the velocity profile are generated; VI. The rheological parameters are calculated, where for the case of the Bingham model, the yield stress and Bingham viscosity are obtained, and for the case of the Herschel-Bulkley model, the yield stress, the exponent and the consistency factor of the suspension; VII. Pressure corrections are made for inlet and outlet effects and for wall slippage; and VIII. The correction for wall effect is made, using the measurement of the velocity profile; h) Generation of trend curves, with alert criteria in case of unexpected variations; i) Automatic and constant repetition of the process; and j) Performance of statistical analysis of the control period.

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