Method and device for measuring water content of sandstone

Abstract

The invention provides a method and a device for measuring the water content of sandstone. The method comprises the following steps: receiving digital data which is transmitted by an ADC (Analog to Digital Converter) chip and is converted by square wave signals with various frequencies after passing through a capacitor; determining capacitive reactance formed by each frequency square wave signal according to the digital data; determining the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of each frequency; determining the dielectric constant of the capacitor according to the capacitance value of the capacitor; estimating the water content of the sandstone according to the dielectric constant of the capacitor; the capacitor has the beneficial effects that after the capacitive reactance formed by each frequency square wave signal is calculated through the FPGA chip according to the digital data, the capacitance value of the capacitor is obtained according to the capacitive reactance formed by each frequency square wave signal, and then the dielectric constant of the capacitor is obtained according to the capacitance value of the capacitor; and finally, the water content of the sandstone is estimated according to the dielectric constant of the capacitor, so that the method is relatively low in cost, simple to operate, free from interference of external factors and high in measurement precision.

Description

Technical Field

[0001] The present invention relates to the technical field of sand and gravel moisture content determination, and in particular to a sand and gravel moisture content determination method and device. Background Art

[0002] Sand and gravel are raw materials widely used in civil engineering projects. The measurement of the moisture content of sand and gravel directly affects the construction efficiency and quality. Therefore, measuring the moisture content of sand and gravel is an indispensable part of civil engineering projects.

[0003] Some methods currently used to measure the moisture content of sand and gravel: 1. Weighing method: The weighing method is a simple, easy and convenient method. First, you need to weigh a certain amount of wet sand and gravel and other materials, and record their mass, then put them in an oven, heat and dry them, and finally take out the sample weight and weigh it again. Compare the difference in mass between the two to get the moisture content. Advantages: simple and easy, low cost, disadvantages: low measurement accuracy, easily affected by environmental factors; 2. Parallel beam method: The parallel beam method is a high-precision and reliable measurement method. During measurement, the sample needs to be placed on a parallel iron beam and squeezed hard, then released and the time for the elastic recovery of the iron beam is recorded. The moisture content can be calculated by comparing the recorded time. Advantages: high measurement accuracy and reliable data, disadvantages: the operation process requires a high degree of expertise and is relatively cumbersome; 3. Microwave drying method: The microwave drying method is an efficient and fast measurement method. This method is suitable for materials with high moisture content, such as soil, mud, etc. During operation, the sample needs to be placed in a microwave drying furnace. Heat and dry at different temperatures, record the weight after drying at different temperatures, and calculate the moisture content by data comparison. Advantages: fast, efficient, and accurate. Disadvantages: relatively high equipment cost; 4. Microwave energy attenuation method: The microwave transmitting-receiving system transmits microwave signals to the sand and gravel. The signal is continuously transmitted and reflected around the sand and gravel to form a propagation loop. Microwave is an electromagnetic wave. The energy attenuation of electromagnetic wave energy in the same medium is proportional to its moisture content. Therefore, the attenuation of electromagnetic energy propagated in the medium is calculated, and then the moisture content of the sand and gravel is determined according to the built-in data model and special algorithm. Advantages: fast measurement speed, high accuracy, non-invasive, not affected by the color and transparency of the measured medium, etc. Disadvantages: easily affected by the surrounding environment, and necessary shielding and anti-interference treatment are required. In addition, there are certain safety hazards in measuring moisture by microwave method, and necessary safety measures need to be taken. Therefore, there is an urgent need for a measurement technology with relatively low equipment cost, simple operation, no interference from external factors and high measurement accuracy. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method and device for determining the moisture content of sand and gravel, which is used to solve the problems in the prior art of relatively high equipment cost, cumbersome operation, susceptibility to interference from external factors and low measurement accuracy.

[0005] To achieve the above objectives and other related objectives, the present invention provides the following technical solutions:

[0006] An embodiment of the present invention provides a method for determining the moisture content of sand and gravel, comprising the following steps: receiving digital data converted from square wave signals of various frequencies sent by an ADC chip through a capacitor; determining the capacitive reactance formed by the square wave signals of various frequencies according to the digital data; determining the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of various frequencies; determining the dielectric constant of the capacitor according to the capacitance value of the capacitor; and estimating the moisture content of sand and gravel according to the dielectric constant of the capacitor.

[0007] An embodiment of the present invention also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the sand and gravel moisture content determination method as described above.

[0008] In one embodiment of the present invention, before receiving the square wave signals of each frequency sent by the ADC chip and converted into digital data after passing through the capacitor, the method further includes: sending the square wave signals of each frequency to the capacitor.

[0009] In one embodiment of the present invention, after sending the square wave signals of each frequency to the capacitor and before receiving the digital data converted from the square wave signals of each frequency sent by the ADC chip after passing through the capacitor, it also includes: receiving the digital data converted from the square wave signals of each frequency after passing through the capacitor, and then sending the received digital data to the FPGA chip.

[0010] In one embodiment of the present invention, two plates are installed in the capacitor, the material of the plates is titanium alloy, wires are led out from the two plates, and sand and gravel to be measured are filled between the two plates, and the sand and gravel to be measured serve as the dielectric material between the two plates of the capacitor.

[0011] In one embodiment of the present invention, the determining the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of each frequency includes: determining the capacitance value of the capacitor of each frequency according to the capacitive reactance formed by the square wave signals of each frequency; averaging the capacitance values ​​of the capacitors of each frequency, and determining the capacitance value of the capacitor according to the processing result.

[0012] In one embodiment of the present invention, the step of determining the capacitance value of each frequency capacitor according to the capacitive reactance formed by the square wave signal of each frequency includes: determining the capacitance value of each frequency capacitor according to the following formula: c =1 / (2×π×f×C), where X cis the capacitive reactance, f is the frequency, and C is the capacitance value of the capacitor.

[0013] In one embodiment of the present invention, determining the dielectric constant of the capacitor based on the capacitance value of the capacitor includes: determining the dielectric constant of the capacitor according to the following formula: ε=C×d / A, wherein ε is the dielectric constant of the capacitor, A is the area of ​​the titanium alloy plate in the capacitor, and d is the distance between the two titanium alloy plates.

[0014] In one embodiment of the present invention, estimating the moisture content of sand and gravel based on the dielectric constant of the capacitor includes: estimating the moisture content of sand and gravel according to the following formula: f(ε)=aε×ε×ε+bε×ε, wherein moisture content=f(ε), ε is the dielectric constant of the capacitor, a is the aggregate fineness modulus coefficient, and b is the aggregate material coefficient.

[0015] A device for measuring the moisture content of sand and gravel comprises an FPGA chip, an ADC chip connected to the FPGA chip, and a capacitor located between a transmitting end of the FPGA chip and a receiving end of the ADC chip, wherein a DC power amplifier circuit is provided at both the transmitting end of the FPGA chip and the receiving end of the ADC chip; a measuring circuit is formed between the FPGA chip, the ADC chip and the DC power amplifier circuit, the positive electrode of the capacitor is connected in parallel with the measuring circuit, the negative electrode of the capacitor is grounded, the capacitor comprises two plates, wires are led out from both the plates, and the space between the two plates is filled with sand and gravel to be measured.

[0016] As described above, a sand and gravel moisture content determination method and device of the present invention has the following beneficial effects:

[0017] The capacitor in the present invention is composed of two titanium alloy plates and sand and gravel to be measured filled between the two titanium alloy plates, and each frequency square wave signal can be sent through the FPGA chip, each frequency square wave signal is attenuated and filtered by the capacitor and then received by the ADC chip, the ADC chip receives the digital data converted by each frequency square wave signal after passing through the capacitor, and then sends the received digital data to the FPGA chip, the FPGA chip calculates the capacitive reactance formed by each frequency square wave signal according to the digital data, and then calculates the capacitance value of each frequency capacitor according to the capacitive reactance formed by each frequency square wave signal, and then averages the capacitance value of each frequency capacitor, the average value is the capacitance value of the capacitor, and then calculates the dielectric constant of the capacitor according to the capacitance value of the capacitor, and finally estimates the water content of the sand and gravel according to the dielectric constant of the capacitor, so that the present invention is not only relatively low in cost and simple in operation, but also not subject to interference from external factors and has high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of a method for determining the moisture content of sand and gravel in a first embodiment of the present invention;

[0019] Figure 2 is a flow chart of a method for determining the moisture content of sand and gravel in a second embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a capacitor in a sand and gravel moisture content measuring device in a third embodiment of the present invention;

[0021] Figure 4 is an overall schematic diagram of a sand and gravel moisture content measuring device in a third embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of an electronic device in a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0024] Generally speaking, electric charges will move under the influence of force in an electric field. When there is a medium between conductors, the movement of charges is hindered and the charges are accumulated on the conductors, resulting in the accumulation and storage of charges. The device that stores charges is called a capacitor. The characteristics of a capacitor mainly depend on the following factors: 1. The geometric shape and size of the capacitor: The area and spacing of the capacitor are important factors in determining the capacitance. The larger the area, the larger the capacity of the capacitor, and the smaller the spacing, the larger the capacity of the capacitor; 2. The relative dielectric constant of the medium: The medium is the insulating material between the two electrodes. Its relative dielectric constant determines the polarization ability and charge storage ability of the medium. The larger the relative dielectric constant, the larger the capacity of the capacitor; 3. The material and structure of the capacitor: Capacitors of different materials have different capacities. For example, electrolytic capacitors have relatively high capacities, while ceramic capacitors have relatively low capacities. In addition, the design of the capacitor structure will also affect the capacity; 4. Working voltage: The capacity of a capacitor is related to the voltage it can withstand. Under normal circumstances, the capacity of a capacitor will decrease as the voltage it can withstand increases.

[0025] When an AC signal is applied between the two poles of a capacitor, the charges will continuously move back and forth between the two poles, forming the storage and release of the electric field. In the process of the charges moving from one pole to the other, the current inside the capacitor will also change accordingly, thereby transmitting the AC signal.

[0026] The first embodiment of the present invention relates to a method for determining the moisture content of sandstone. Figure 1 As shown, it is applied to FPGA chips, as follows:

[0027] Step 101, receiving square wave signals of various frequencies sent by the ADC chip and converting them into digital data after passing through the capacitor.

[0028] Specifically, two plates are installed in the capacitor, the material of the plates is titanium alloy, wires are led out from the two plates, and sand and gravel to be measured are filled between the two plates, and the sand and gravel to be measured serves as the dielectric material between the two plates of the capacitor.

[0029] Step 102: determine the capacitive reactance formed by the square wave signals of each frequency according to the digitized data.

[0030] Specifically, impedance includes resistance, inductive reactance and capacitive reactance. In DC signals, resistance is the factor that causes signal attenuation, and in AC signals, impedance is the factor that causes signal attenuation. Therefore, in a circuit, the role of impedance is the same as that of resistance, or resistance is a special case of impedance under DC signals. If in a circuit, only capacitive reactance forms impedance, then in this circuit capacitive reactance = impedance. In this case, the ratio of input to output is capacitive reactance.

[0031] Step 103, determining the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of each frequency.

[0032] Specifically, the capacitance value of each frequency capacitor is first determined according to the capacitive reactance formed by the square wave signal of each frequency, and then the capacitance value of each frequency capacitor is averaged, and the capacitance value of the capacitor is determined according to the processing result.

[0033] Step 104: determine the dielectric constant of the capacitor according to the capacitance value of the capacitor.

[0034] Specifically, the dielectric constant of the capacitor is determined according to the following formula: ε=C×d / A, wherein ε is the dielectric constant of the capacitor, A is the area of ​​the titanium alloy plate in the capacitor, and d is the distance between the two titanium alloy plates.

[0035] Step 105, estimating the water content of the sand and gravel according to the dielectric constant of the capacitor.

[0036] Specifically, the moisture content of sand and gravel is estimated according to the following formula: f(ε)=aε×ε×ε+bε×ε, where moisture content=f(ε), ε is the dielectric constant of the capacitor, a is the aggregate fineness modulus coefficient, and b is the aggregate material coefficient.

[0037] The present invention sends square wave signals of various frequencies through an FPGA chip, and the square wave signals of various frequencies are received by an ADC chip after being attenuated and filtered by a capacitor. After the ADC chip receives the digital data converted from the square wave signals of various frequencies through the capacitor, the ADC chip sends the received digital data to the FPGA chip. After the FPGA chip calculates the capacitive reactance formed by the square wave signals of various frequencies according to the digital data, it calculates the capacitance value of the capacitors of various frequencies according to the capacitive reactance formed by the square wave signals of various frequencies, and then averages the capacitance values ​​of the capacitors of various frequencies, the average value being the capacitance value of the capacitor, and then calculates the dielectric constant of the capacitor according to the capacitance value of the capacitor, and finally estimates the water content of sand and gravel according to the dielectric constant of the capacitor. Therefore, the present invention is not only relatively low in cost and simple in operation, but also not subject to interference from external factors and has high measurement accuracy.

[0038] The second embodiment of the present invention relates to a method for determining the moisture content of sand and gravel. The second embodiment is a detailed discussion of the first embodiment as a whole. The main detailed discussion is: in the second embodiment of the present invention, an embodiment is clarified, and this embodiment discusses the specific process of determining the capacitance value of the capacitor based on the capacitive reactance formed by square wave signals of each frequency.

[0039] For this implementation, please refer to Figure 2 , including the following steps, are described as follows:

[0040] Step 201, sending square wave signals of various frequencies to the capacitor.

[0041] Specifically, the square wave signals of each frequency sent by the FPGA chip are a series of square waves with a frequency range of 1KHz to 10KHz, a frequency step of 100Hz, an amplitude of 12V, and each frequency point lasting 1 second.

[0042] Step 202, receiving the digital data converted from the square wave signals of each frequency through the capacitor, and then sending the received digital data to the FPGA chip.

[0043] Specifically, it is applied to the ADC chip, that is, the ADC chip receives the digital data converted from the square wave signals of various frequencies through the capacitor, and then sends the received digital data to the FPGA chip.

[0044] Step 203 to step 204 are similar to step 101 to step 102 in the first embodiment, and are not described again herein.

[0045] Step 205, determining the capacitance value of each frequency capacitor according to the capacitive reactance formed by the square wave signal of each frequency.

[0046] Specifically, the capacitance value of each frequency capacitor is determined according to the following formula: c =1 / (2×π×f×C), where Xc is the capacitive reactance, f is the frequency, and C is the capacitance value of the capacitor.

[0047] Step 206, averaging the capacitance values ​​of the frequency capacitors, and determining the capacitance value of the capacitor according to the processing result.

[0048] Step 207 to step 208 are similar to step 104 to step 105 in the first embodiment, and are not described in detail here.

[0049] The third embodiment of the present invention relates to a sand and gravel moisture content measuring device, see Figure 3 and Figure 4 , including an FPGA chip, an ADC chip connected to the FPGA chip, and a capacitor located between the transmitting end of the FPGA chip and the receiving end of the ADC chip. A DC power amplifier circuit is provided at the transmitting end of the FPGA chip and the receiving end of the ADC chip. A measuring circuit is formed between the FPGA chip, the ADC chip and the DC power amplifier circuit. The positive pole of the capacitor is connected in parallel with the measuring circuit, and the negative pole of the capacitor is grounded. The capacitor includes two plates, and wires are led out from the two plates. Sand and gravel to be measured are filled between the two plates.

[0050] A fourth embodiment of the present invention relates to an electronic device, see Figure 5 ,include:

[0051] At least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above sand and gravel moisture content determination method.

[0052] Among them, the memory and the processor are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors and memories together. The bus can also connect various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor is transmitted on a wireless medium via an antenna, and further, the antenna also receives data and transmits the data to the processor.

[0053] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

[0054] The capacitor in the present invention is composed of two titanium alloy plates and sand and gravel to be measured filled between the two titanium alloy plates, and each frequency square wave signal can be sent through the FPGA chip, each frequency square wave signal is attenuated and filtered by the capacitor and then received by the ADC chip, the ADC chip receives the digital data converted by each frequency square wave signal after passing through the capacitor, and then sends the received digital data to the FPGA chip, the FPGA chip calculates the capacitive reactance formed by each frequency square wave signal according to the digital data, and then calculates the capacitance value of each frequency capacitor according to the capacitive reactance formed by each frequency square wave signal, and then averages the capacitance value of each frequency capacitor, the average value is the capacitance value of the capacitor, and then calculates the dielectric constant of the capacitor according to the capacitance value of the capacitor, and finally estimates the water content of the sand and gravel according to the dielectric constant of the capacitor, so that the present invention is not only relatively low in cost and simple in operation, but also not subject to interference from external factors and has high measurement accuracy.

[0055] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. All equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for determining the moisture content of sand and gravel, characterized in that: Applied to FPGA chip, including the following steps: Receive the square wave signals of various frequencies sent by the ADC chip and convert them into digital data after passing through the capacitor; Determine the capacitive reactance formed by the square wave signals of each frequency according to the digitized data; Determine the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of each frequency; Determining a dielectric constant of the capacitor according to a capacitance value of the capacitor; The water content of the sand and gravel is estimated according to the dielectric constant of the capacitor.

2. A method for measuring the moisture content of sand and gravel according to claim 1, characterized in that: Before the square wave signals of each frequency sent by the receiving ADC chip are converted into digital data after passing through the capacitor, the method further includes: Send square wave signals of various frequencies to the capacitor.

3. A sand and gravel moisture content determination method according to claim 2, applied to an ADC chip, characterized in that: After sending the square wave signals of each frequency to the capacitor and before receiving the digital data converted from the square wave signals of each frequency sent by the ADC chip through the capacitor, the method further includes: The square wave signals of each frequency are received and converted into digital data after passing through the capacitor, and then the received digital data is sent to the FPGA chip.

4. The method for determining the moisture content of sand and gravel according to claim 1, wherein: Two plates are installed in the capacitor. The material of the plates is titanium alloy. Wires are led out from the two plates. Sand and gravel to be measured are filled between the two plates. The sand and gravel to be measured serve as the dielectric material between the two plates of the capacitor.

5. A method for measuring the moisture content of sand and gravel according to claim 4, characterized in that: The step of determining the capacitance value of the capacitor according to the capacitive reactance formed by the square wave signals of each frequency includes: Determine the capacitance value of the capacitor at each frequency according to the capacitive reactance formed by the square wave signal at each frequency; The capacitance values ​​of the capacitors at each frequency are averaged, and the capacitance value of the capacitor is determined according to the average processing result.

6. A method for measuring the moisture content of sand and gravel according to claim 5, characterized in that: The method of determining the capacitance value of each frequency capacitor according to the capacitive reactance formed by the square wave signals of each frequency includes: Determine the capacitance value of the capacitor for each frequency using the following formula: X c =1 / (2×π×f×C), where X c is the capacitive reactance, f is the frequency, and C is the capacitance value of the capacitor.

7. A method for measuring the moisture content of sand and gravel according to claim 6, characterized in that: Determining the dielectric constant of the capacitor according to the capacitance value of the capacitor includes: The dielectric constant of the capacitor is determined according to the following formula: ε=C×d / A, where ε is the dielectric constant of the capacitor, A is the area of ​​the titanium alloy plate in the capacitor, and d is the distance between the two titanium alloy plates.

8. A method for measuring the moisture content of sand and gravel according to claim 7, characterized in that: The step of estimating the water content of sand and gravel according to the dielectric constant of the capacitor comprises: The moisture content of sand and gravel can be estimated according to the following formula: f(ε)=aε×ε×ε+bε×ε, where moisture content=f(ε), ε is the dielectric constant of the capacitor, a is the aggregate fineness modulus coefficient, and b is the aggregate material coefficient.

9. A device for measuring the moisture content of sand and gravel, characterized in that: It includes an FPGA chip, an ADC chip connected to the FPGA chip, and a capacitor located between a transmitting end of the FPGA chip and a receiving end of the ADC chip, wherein a DC power amplifier circuit is provided at the transmitting end of the FPGA chip and at the receiving end of the ADC chip; A measuring circuit is formed between the FPGA chip, the ADC chip and the DC power amplifier circuit. The positive electrode of the capacitor is connected in parallel with the measuring circuit, and the negative electrode of the capacitor is grounded. The capacitor includes two plates, and wires are led out from both plates. Sand and gravel to be measured are filled between the two plates.

10. An electronic device, characterized in that: include: at least one processor; as well as, A memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the sand and gravel moisture content determination method as described in any one of claims 1 to 8.

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