A gamma-ray-based coal ash detection device

Abstract

The present invention provides a coal ash detection device based on gamma rays, which includes a coal seam thickness regulation device, a controller, a laser rangefinder connected to the controller, a gamma ray source, a detector, an amplifier, a multi-channel analyzer, and an electric control machine system, belonging to the field of coal industry index detection. When the clean coal is transported to the belt conveyor, the coal seam thickness regulation device is responsible for adjusting the thickness of the coal seam to reduce the influence of high-density substances such as steel wires in the belt of the belt conveyor on the measurement results. The laser rangefinder sends the adjusted coal seam thickness signal to the controller, and the other end of the controller is connected to the starting device of the belt conveyor. When the coal seam thickness is low, the rotation speed of the belt conveyor is reduced. The detector includes a gamma ray source, a detector, a multi-channel analyzer, and an electric control machine system to achieve continuous measurement of ash content. The temperature sensor in the radiation source box is used to regulate the temperature of the radiation source box, reduce the influence of temperature on the measurement results, and improve the accuracy of the measurement results.

Description

Technical Field

[0001] The present invention relates to the field of coal industrial index detection, and more specifically, to a gamma-ray-based coal ash detection device. Background Art

[0002] Coal ash is an important index of coal quality. The current commonly used detection method is chemical inspection method, but the chemical inspection method has a relatively large lag and cannot perform real-time online detection. With the continuous improvement of modern electronic technology and the continuous popularization of the civilian use of nuclear physics technology, the online detection technology of coal ash has become feasible. The dual-detector coal ash detector absorbs the advantages of the nuclear instrument design principle and has been widely used in industrial, medical and other fields.

[0003] The implementation method of the dual-energy gamma-ray online ash detector is that at one end of the belt, two radioactive sources Am 241 and Cs 137 are used to emit low-energy and medium-energy gamma rays respectively to irradiate the coal seam on the belt. At the other end of the belt, a detector is set to collect the ray signals after the coal is irradiated. Different substances in the coal have different absorption efficiencies for the two kinds of rays. The mass fraction of high-Z elements in the coal can be measured by measuring the attenuation absorption when the low-energy ray Am 241 transmits through the coal. The medium-energy gamma ray Cs 137 can be used to monitor the change of the mass thickness of the coal and realize the rapid determination of ash.

[0004] Application No. 20121203270.3 uses medium-energy Cs 137 gamma rays to irradiate the coal sample in the coal bunker, and at the same time generates X-rays of 32 Kev, effectively saving the resource cost. However, the disadvantage is that the coal seam thickness will interfere with the detection result. When using the traditional single-detector dual-energy gamma-ray online ash detector, the medium-energy gamma-ray source will interfere with the low-energy gamma-ray source, resulting in inaccurate measurement results. It will also be interfered by internal factors such as the coal type composition and external factors such as the coal seam thickness, moisture and other impurities contained, resulting in a large detection error. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a gamma-ray-based coal ash detection device, which can reduce the influence of interference factors on the result in coal ash detection, thereby improving the efficiency and accuracy of coal ash detection; a gamma-ray-based coal ash detection device provided by the present invention includes a coal seam thickness control device, a controller, a laser rangefinder connected to the controller, a gamma-ray source, a detector, an amplifier, a multi-channel analyzer (14), and an electric control machine system;

[0006] The coal seam thickness control device includes three baffles. Baffle 1 (1) is located on the right side of the belt conveyor belt, inclined at 45 degrees to the belt plane, adjusting the coal flow at the right edge of the belt to the left. Baffle 2 (2) is located on the right side of the belt conveyor belt, inclined at 45 degrees to the belt plane, adjusting the coal flow at the left edge of the belt to the right. Baffle 3 (3) is inclined at 30 degrees to the belt, leveling the coal flow in the middle of the belt;

[0007] The laser rangefinder is used to detect the thickness of the coal seam adjusted by the coal seam thickness control device and send the thickness signal to the controller;

[0008] The gamma-ray source includes a medium-energy gamma-ray source Cs 137 and a low-energy gamma-ray source Am 241 for emitting gamma rays to the coal seam;

[0009] The detector includes a ray detector A and a ray detector B, which are used to collect the characteristic rays emitted by the coal seam and send the ray signal to the multi-channel analyzer;

[0010] The medium-energy gamma-ray source Cs 137 emits rays to irradiate the coal seam. The medium-energy gamma rays passing through the coal seam and the characteristic X-rays of calcium and iron excited by the medium-energy gamma-ray irradiation are received by detector A; The low-energy gamma-ray source Am 241 emits rays to irradiate the coal seam, and the low-energy gamma rays passing through the coal seam are received by ray detector B;

[0011] The controller is used to receive the coal seam thickness signal sent by the laser rangefinder and adjust the rotation speed of the belt conveyor according to the strength of the signal;

[0012] The amplifier is a photomultiplier tube, serving as an intermediary connecting the output end of the detector and the input end of the multi-channel analyzer; The multi-channel analyzer is used to receive the gamma-ray signal and X-ray signal passing through the coal seam;

[0013] The electronic control machine system is used to analyze the X-ray absorption peak and gamma-ray full-energy peak.

[0014] Combined with the first aspect, the embodiment of the present invention provides the first possible implementation manner of the first aspect. Among them, the device further includes: a radiation source box, a heat dissipation device;

[0015] The heat dissipation device and the gamma-ray source are located in the radiation source box;

[0016] The controller is further used to maintain the radiation source box within the normal range.

[0017] Combined with the first aspect, the embodiment of the present invention provides the second possible implementation manner of the first aspect. Among them, the radiation source box includes a radiation source protection window A and a radiation source protection window B;

[0018] The medium energy gamma ray source Cs 137 Located in the radiation source protection window A, the low-energy gamma ray source Am 241 Located in the radiation protection window B;

[0019] The radiation source protection window is made of lead and 304 stainless steel, with double layers of stainless steel inside and outside, and has a flat-opening protection door that is easy to open and close, and is respectively provided with a collimation hole A and a collimation hole B;

[0020] The medium energy gamma ray source Cs 137 The center is on the central axis of the collimator hole A, and the low-energy gamma ray source Am 241 The center is on the central axis of the collimating hole B, and the collimating hole has a depth of 7 cm and a hole diameter of 1 cm.

[0021] In combination with the first aspect, the embodiment of the present invention provides a third possible implementation of the first aspect, wherein the heat dissipation device includes a temperature sensor and a heat dissipation valve;

[0022] The temperature sensor is used to transmit the current temperature in the radiation source box to the controller;

[0023] The heat dissipation valve is a heat dissipation sensor valve, the start and stop states of which are controlled by a controller and are responsible for regulating the temperature of the radiation source box;

[0024] When the temperature in the radiation source box is higher than the preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensor valve to the start state;

[0025] When the temperature in the radiation source box is lower than a preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensing valve to a ready state.

[0026] In combination with the first aspect, the embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the electronic control machine system includes a power supply, an energy signal transmission system, a spectrum analysis system, and a display system;

[0027] The energy signal transmission system is connected to the output end of the multi-channel spectrometer, and transmits the processed signal to the spectrum analysis system, and the data processed by the spectrum analysis system is sent to the display system.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention adopts a coal seam thickness control device to adjust the thickness of the coal seam on the belt conveyor, thereby reducing the influence of high-density materials such as steel wire in the belt conveyor belt on the measurement results due to the low thickness of the coal seam;

[0030] 2. The present invention utilizes a laser rangefinder and a controller as a flow monitoring device on a belt conveyor to timely adjust the rotation speed of the belt conveyor.

[0031] 3. The present invention utilizes the X-rays generated by the excitation of medium-energy gamma rays, and compensates for the influence of coal type changes on the measurement results by calculating the calcium and iron contents using the characteristic X-rays of calcium and iron.

[0032] 4. The medium-energy gamma rays utilized by the present invention serve as both a gamma ray excitation source to compensate for the measurement error caused by the change in coal seam thickness, and on the other hand, as an excitation source for X-rays.

[0033] 5. The present invention can be applied to the automatic and rapid detection of coal samples on a clean coal belt conveyor. Without using a bypass belt, it can be installed and detected.

[0034] 6. This method is simple and highly executable. Brief Description of the Drawings

[0035] Figure 1 It is a schematic structural diagram of an embodiment of a gamma-ray-based coal ash detection device provided by the present invention;

[0036] Figure 2 It is a schematic structural diagram of an embodiment of a thickness adjustment device provided by the present invention;

[0037] Among them, 1 is baffle 1; 2 is baffle 2; 3 is baffle 3. Detailed Embodiment

[0038] As can be seen from the schematic structural diagram of a gamma-ray-based coal ash detection device provided by the present invention, the detection device includes a coal seam thickness adjustment device, a controller, a laser rangefinder connected to the controller, a gamma-ray source, a detector, an amplifier, a multi-channel analyzer, and an electric control machine system. Figure 1 As can be seen, the detection device includes a coal seam thickness adjustment device, a controller, a laser rangefinder connected to the controller, a gamma-ray source, a detector, an amplifier, a multi-channel analyzer, and an electric control machine system.

[0039] The specific structure of the coal seam thickness adjustment device is as Figure 2 shown, including 3 baffles. Baffle 1 (1) is located on the right side of the belt of the belt conveyor, closest to the blanking chute, and is inclined at 45 degrees to the belt plane, adjusting the coal flow on the right edge of the belt to the left. Baffle 2 (2) is located on the right side of the belt of the belt conveyor, inclined at 45 degrees to the belt plane, adjusting the coal flow on the left edge of the belt to the right. Baffle 3 (3) is closest to the radiation source and is installed inclined to the horizontal plane, leveling the coal flow in the middle of the belt. When cotton impurities pass through baffle 3 (3), due to the impact of the clean coal flow on baffle 3 (3), the cotton impurities are washed away and transported to the next process together with the clean coal flow, thus eliminating the influence of impurities on the measurement of the on-line ash meter.

[0040] After the thickness of the coal seam is adjusted, the current thickness of the coal seam is recorded when it passes through the laser rangefinder. The thickness information of the coal seam is then transmitted to the controller connected to the laser rangefinder. One end of the controller is connected to the power system of the belt conveyor and adjusts the speed of the belt conveyor wheel according to the thickness information.

[0041] The gamma ray source provided by the present invention comprises an upper medium energy gamma ray source Cs 137 and the low-energy gamma-ray source Am located at the bottom 241 , medium energy gamma ray source Cs 137 Located in the radiation source protection window A, the low-energy gamma ray source Am 241 Located inside the radiation protection window B.

[0042] The source protection window is made of lead and 304 stainless steel, with double stainless steel inside and outside, with a flat-opening protection door that is easy to open and close, and is equipped with collimation holes A and B respectively; medium-energy gamma-ray source Cs 137 The center is on the central axis of the collimator hole A, and the low-energy gamma ray source Am 241 The center is on the central axis of the collimating hole B, the collimating hole has a depth of 7 cm and a diameter of 1 cm.

[0043] Medium Energy Gamma Ray Source Cs 137 The coal seam on the belt conveyor is irradiated through the collimator hole A, and the low-energy gamma ray source Am 241 The coal seam on the belt conveyor is illuminated through the collimating hole B.

[0044] The temperature sensor transmits the current temperature in the radiation source box to the controller. When the temperature in the radiation source box is higher than the preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensor valve to the start state. When the temperature in the radiation source box is lower than the preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensor valve to the ready state.

[0045] The detector includes a radiation detector A located at the top and a radiation detector B located at the bottom. The position of the radiation detector A is the same as that of the medium energy gamma ray source Cs. 137 The position of the ray detector B corresponds to that of the low-energy gamma-ray source Am, which is used to receive the medium-energy gamma-rays that penetrate the coal seam and the characteristic X-rays that excite calcium and iron in the coal sample by medium-energy gamma-ray irradiation. 241 corresponds to the position of the coal seam and is used to receive low-energy gamma rays that penetrate the coal seam.

[0046] The output end of the ray detector A is connected to the input end of the amplifier A, the output end of the ray detector B is connected to the input end of the amplifier B, and the amplifier A and the amplifier B are respectively connected to an input end of the multi-channel analysis spectrometer.

[0047] The input ends of the multi-channel analyzer are respectively connected to amplifier A and amplifier B, used to receive gamma-ray signals passing through the coal seam and X-ray signals of calcium and iron in the coal sample. The output end of the multi-channel analyzer is connected to the electric control system.

[0048] The electric control system includes a power supply, an energy signal transmission system, a spectrum resolution system, and a display system. The input end of the spectrum resolution system is connected to the output end of the multi-channel analyzer, and the processed data is sent to the display system. The input end of the display system is connected to the output end of the spectrum resolution system.

[0049] In the specific operation:

[0050] Step S1, the coal sample is conveyed from the feeding chute to the belt conveyor. Baffle 1 adjusts the coal flow on the right edge of the belt to the left, baffle 2 adjusts the coal flow on the left edge of the belt to the right, and baffle 3 levels the coal flow in the middle of the belt. The laser rangefinder measures the thickness of the coal seam at this time and transmits it to the controller, and the controller adjusts the rotation speed of the belt conveyor.

[0051] Step S2, the medium-energy gamma-ray source Cs 137 irradiates the coal seam on the belt conveyor through collimating hole A, and the low-energy gamma-ray source Am 241 irradiates the coal seam on the belt conveyor through collimating hole B. The ray detector A receives the medium-energy gamma rays penetrating the coal seam and the characteristic X-rays of calcium and iron excited by the medium-energy gamma-ray irradiation in the coal sample. The ray detector B receives the low-energy gamma rays penetrating the coal seam, and after passing through amplifier A and amplifier B, the ray signals are respectively sent to the multi-channel analyzer.

[0052] Step S3, the energy signal transmission system connects to the output end of the multi-channel analyzer, transmits the processed signal to the spectrum resolution system, uses the low-energy gamma to detect the content of high-Z elements in the coal, uses the medium-energy gamma to monitor the change of the mass thickness of the coal, and uses the calcium and iron content detected by the X-ray to compensate for the influence of coal type change on the measurement result. The data processed by the spectrum resolution system is sent to the display system to obtain the ash content value of the coal.

[0053] In summary, the gamma-ray-based coal ash detection device designed by the present invention detects the ash content of the coal seam by analyzing the changes of dual-energy gamma rays and X-rays, effectively improving the accuracy of ash measurement. The method is simple, highly executable, and highly reliable.

[0054] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments, or replace the technical solutions and means therein; and these modifications and replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A gamma-ray based coal ash detection device, comprising a coal seam thickness control device, a controller, a laser rangefinder connected to the controller, a gamma-ray source, a detector, an amplifier, a multi-channel spectrometer, and an electronic control system, characterized in that: The coal seam thickness control device is used to adjust the thickness of the coal seam located on the belt conveyor, and reduce the influence of the high-density steel wire material in the belt of the belt conveyor on the measurement result; The laser rangefinder is used to detect the thickness of the coal seam after being adjusted by the coal seam thickness control device, and send the thickness signal to the controller; The gamma ray source includes a medium energy gamma ray source Cs 137 and low energy gamma ray sources Am 241 Used to send gamma rays into coal seams; The detectors include a ray detector A and a ray detector B, which are used to collect characteristic rays emitted by the coal seam and send ray signals to a multi-channel analytical spectrometer; The medium-energy gamma-ray source Cs 137 Emits rays to irradiate the coal seam. The medium-energy gamma rays passing through the coal seam and the characteristic X-rays of calcium and iron excited by the medium-energy gamma-ray irradiation in the coal sample are received by detector A; The low-energy gamma-ray source Am 241 Emits rays to irradiate the coal seam. The low-energy gamma rays passing through the coal seam are received by ray detector B; The controller is used to receive the coal seam thickness signal sent by the laser rangefinder and adjust the speed of the belt conveyor according to the strength of the signal; The amplifier is a photomultiplier tube, which serves as an intermediary between the detector output and the multi-channel spectrometer input; The multi-channel analytical spectrometer is used to receive gamma ray signals and X-ray signals that penetrate the coal seam; The device further comprises: a radiation source box, a heat sink, and an electric control system; the heat sink and the gamma ray source are located in the radiation source box; the electric control system is connected to the output end of the multi-channel analysis spectrometer; The controller is also used to control the start and stop of the heat dissipation device to maintain the temperature in the source box within a normal range; the coal seam thickness control device includes three baffles, baffle 1 (1) adjusts the coal flow at the right edge of the belt to the left, baffle 2 (2) adjusts the coal flow at the left edge of the belt to the right, and baffle 3 (3) makes the coal flow in the middle of the belt smooth and tidy.

2. The device according to claim 1, wherein the radiation source box comprises a radiation source protection window A and a radiation source protection window B, and the medium-energy gamma-ray source Cs 137 is located inside the radiation source protection window A, and the low-energy gamma-ray source Am 241 is located inside the radiation source protection window B, and is characterized in that: The radiation source protection window is made of lead and 304 stainless steel, with double layers of stainless steel inside and outside, and has a flat-opening protection door that is easy to open and close, and is respectively provided with a collimation hole A and a collimation hole B; The medium-energy gamma-ray source Cs 137 The center is on the central axis of the collimation hole A, and the low-energy gamma-ray source Am 241 The center is on the central axis of the collimation hole B. The depth of the collimation hole is 7 cm and the aperture is 1 cm.

3. The device according to claim 1, wherein the heat dissipation device comprises a temperature sensor and a heat dissipation valve, wherein: The temperature sensor is used to transmit the current temperature in the radiation source box to the controller; The start and stop states of the heat dissipation valve are controlled by a controller.

4. The device according to claim 3, wherein the heat dissipation valve is a heat dissipation sensor valve, which is responsible for regulating the temperature of the radiation source box, and is characterized in that: When the temperature in the radiation source box is higher than the preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensor valve to the start state; When the temperature in the radiation source box is lower than a preset temperature value, the temperature sensor sends a signal to the controller, and the controller sets the heat dissipation sensing valve to a ready state.

5. The device according to claim 1, wherein the electronic control system comprises a power supply, an energy signal transmission system, a spectrum analysis system, and a display system, and is characterized in that: The energy signal transmission system is connected to the output end of the multi-channel spectrometer, and transmits the processed signal to the spectrum analysis system, and the data processed by the spectrum analysis system is sent to the display system.

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