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BR-102019016715-B1 - SYSTEM AND METHOD FOR MEASURING THE MOISTURE CONTENT OF A SOIL OR ORE SAMPLE

BR102019016715B1BR 102019016715 B1BR102019016715 B1BR 102019016715B1BR-102019016715-B1

Abstract

SYSTEM AND METHOD FOR MEASURING THE MOISTURE CONTENT OF A SOIL OR ORE SAMPLE The present invention relates to a benchtop and/or portable system for measuring, in real time, the moisture content of iron ore. The technique of the present invention measures the moisture content of a soil or ore sample by means of impedance variations of a sample with apparent density standardized by the system itself, the system comprising means for compressing (2) the sample until it reaches a predetermined apparent density and means for measuring (12, 14) the moisture content of the sample in a compressed state. The present invention further provides a method associated with the aforementioned system.

Inventors

  • ALAN KARDEK RÊGO SEGUNDO
  • CARINA CARLA APARECIDA FELIPE DA SILVA
  • ÉRICA SILVA PINTO
  • MARCELO EUSTÁQUIO HAMANAKA SILVA
  • PAULO MARCOS DE BARROS MONTEIRO
  • SÁVIO AUGUSTO LOPES DA SILVA
  • THOMÁS VARGAS BARSANTE E PINTO
  • VINÍCIUS NUNES LAGE

Assignees

  • UNIVERSIDADE FEDERAL DE OURO PRETO - UFOP
  • VALE S.A.
  • ASSOCIAÇÃO INSTITUTO TECNOLÓGICO VALE - ITV

Dates

Publication Date
20260317
Application Date
20190813

Claims (9)

  1. 1. System for measuring the moisture content of a soil or ore sample, characterized by comprising: means for compressing (2) the sample until it reaches a predetermined apparent density, the compression means being an electromechanical press (2) comprising a test cell (4) and a movable lid (6) actuated by a threaded rod (8) driven by an electric motor (10); a load cell (11) positioned below the location where the sample is compressed to determine the sample mass; and means for measuring (12, 14) the moisture content of the sample in a compressed state, the means for measuring being at least two electrodes (12) parallel to each other and a processing unit (14) adapted to perform at least one of: controlling the means for compressing (2) the sample via a closed-loop circuit; controlling the means for measuring (12, 14) and processing the signal received from them; and calculating the moisture content of the sample based on the measured impedance and apparent density signal.
  2. 2. System according to claim 1, characterized by further comprising at least one sample temperature sensor in communication with the processing unit (14).
  3. 3. System, according to any one of claims 1 to 2, characterized in that the load cell is in communication with the central processing unit (14).
  4. 4. System, according to any one of claims 1 to 3, characterized by being portable.
  5. 5. Method for measuring the moisture content of a soil or ore sample, using the system for measuring the moisture content of a soil or ore sample as defined in claim 1, characterized by comprising the steps of: compressing the sample until it reaches a predetermined apparent density; and measuring the moisture content of the sample in a compressed state; the compression step being carried out by an electromechanical press (2) comprising: a test cell (4); and a movable lid, the compression being carried out by the movement of the movable lid (6) in relation to the test cell (4) where the sample is located; and a secondary electromechanical system in the form of a hood (16) adapted so as not to transfer the compression force from the press to the load cell (11).
  6. 6. Method according to claim 5, characterized in that the movable cover comprises a threaded rod (8) driven by a first electric motor (10), and a hood (16) driven by a second electric motor (17).
  7. 7. Method, according to any one of claims 5 and 6, characterized in that the measuring step is performed by at least two electrodes (12) parallel to each other and a processing unit (14).
  8. 8. Method, according to any one of claims 5 to 7, characterized by a processing unit (14) being adapted to perform at least one of the steps of: controlling the means to compress (2) the sample via a closed loop circuit; controlling the means to measure (12, 14) and processing the signal received from them; and calculating the moisture content of the sample based on the measured impedance and apparent density signal.
  9. 9. Method according to claim 8, characterized in that the processing unit (14) is adapted to additionally perform the step of measuring the sample temperature, and compensate for its effect on the moisture measurement.

Description

FIELD OF THE INVENTION [0001] The present invention relates to systems or devices for measuring moisture in soils or ores. In particular, the present invention relates to a benchtop and/or portable system for measuring, in real time, the moisture content of iron ore. FUNDAMENTALS OF THE INVENTION [0002] Several techniques are known for measuring moisture in soil or ore samples, such as microwaves, infrared, dimensional physical effects, optical effects, special balances, among others. Some examples of moisture measurement techniques are cited below. [0003] Document PI 0301116-0 A2 discloses a system/method for measuring humidity based on the dimensional change of an expandable core in the sensor that swells with the humidity of the medium and activates a switch indicating the presence of humidity. [0004] Document PI 0510308-8 A8 discloses a system/method for measuring humidity from an LC circuit (with inductor and capacitor) at high frequency, but for measuring humidity in biological systems, such as hair. [0005] Document PI 0519719-8 A2 discloses a system/method for measuring moisture by generating high-frequency signals specifically for moisture content in cotton fibers in bales. [0006] Document BR 10 2013 002485 6 A2 discloses a system/method for measuring moisture by varying the capacitance of a probe in contact with the medium, specifically for soils. [0007] Document PI 0604585-5 A2 also discloses a system/method for measuring moisture content in soils. [0008] Document BR 10 2013 013220-9 A2 reveals the use of the capacitive principle by means of probes to measure moisture specifically for soils. [0009] Document PI 0603443-8 A2 describes an improvement in the dry-basis grinding feeding process based on moisture measurement performed by a sensor that uses an unspecified infrared principle. [0010] However, as can be observed, none of the above documents describing methods for measuring moisture by capacitance takes into account the apparent density of the material being analyzed. It is known that the measured capacitance varies considerably with the density of the material under measurement, since the dielectric constant is dependent on the apparent density. [0011] In an attempt to solve this technical problem, document SU 949472 B discloses a capacitive sensor for measuring soil moisture comprising a capacitive device that compensates for variations in readings as a function of variations in the apparent density of the soil. The device in document SU 949472 B is introduced into the soil and, during the rotation of the rod, the conical tip, under soil reaction pressure, moves relative to the rod, moving a first electrode relative to a second electrode, which is fixed. This movement alters the capacitance of the compensation capacitor formed by these two electrodes. The deformation of the spring, and consequently the movement of the conical tip relative to the rod, is proportional to the apparent density of the soil. The resulting capacitance measured by the device is the sum of the capacitances measured by the sensors and the compensation capacitor. [0012] Although document SU 949472 B reveals capacitance compensation according to the apparent density of the soil, this method could not be applied to measuring the moisture content of ore due to its construction (system comprising rod and spring). [0013] Furthermore, considering the system presented in document SU 949472 B being inserted into soil of unknown apparent density, it is clear that the spring deformation is not solely dependent on the apparent density of that medium. It depends on the force applied by the operator inserting the equipment into the soil, which varies drastically from operator to operator. The opposing force that the soil offers to the equipment depends on several factors besides apparent density, such as the type of material in the soil, the particle size distribution of the material, the moisture content of the material, the heterogeneity of the soil in question, among others. It is evident, therefore, that this method for correcting the effect of density on moisture measurement is inefficient and inaccurate, since the equipment does not measure apparent density. [0014] Therefore, the current state of the art lacks an efficient and accurate technique for measuring the apparent density of soil and ore. As will be seen, the present invention solves the technical problems described above in a practical way. SUMMARY OF THE INVENTION [0015] The main objective of the present invention is to provide a system and a method for measuring the moisture content of a soil or ore sample by means of impedance variations of a sample with apparent density standardized by the system itself. [0016] The present invention has a secondary objective of providing a portable system and a method for measuring the moisture content of a soil or ore sample that allows for real-time measurements. [0017] In order to achieve the above-described objective, the pr