On-line continuous monitoring device and method for gas-solid two-phase flow state in air chute

Abstract

On-line continuous monitoring device and method for gas-solid two-phase flow state in an air chute, comprising a capacitance probe measurement unit arranged at intervals on the air chute, a purging pipeline correspondingly arranged for each group of capacitance probe measurement units, and a PLC automatic control system for overall control of the entire device. An automatic switch valve for the purging pipeline is provided on the purging pipeline; the PLC automatic control system receives signals from the capacitance probe measurement unit and cleans the capacitance probes by controlling the opening and closing of the automatic switch valve for the purging pipeline; the capacitance probe measurement unit includes at least three groups of capacitance probe assemblies connected in parallel, and each group of capacitance probe assemblies includes a fixed capacitor and a capacitance probe connected in series. The present invention can accurately indicate the location where a fault occurs, eliminate the work of manual troubleshooting, and save maintenance time. The PLC automatic control system can regularly open the automatic switch valve on the purging pipeline to purge the capacitance probes so as to maintain the accuracy of detection data.

Description

Technical Field

[0001] The present invention belongs to the technical field of power plant equipment, and more particularly to an on-line continuous monitoring device and method for the gas-solid two-phase flow state in an air chute. Background Art

[0002] An air chute is a device that uses air flow to transport granular materials along a pipeline. Its working principle is to use the kinetic energy of the air flow to make the granular materials suspended and transported along the pipeline with the air flow. It can be used for easily fluidized powdery materials such as cement and fly ash. The air chute has three major transportation characteristics: light weight, low power consumption, and large transportation capacity. Therefore, more and more industries that require powder transportation tend to choose the air chute as a new transportation tool.

[0003] Currently, the air chute generally uses a viewing window to observe the material flow, but it is very difficult to keep the inner side of the viewing window glass clean. During the transportation of materials, the glass is easily contaminated with dust particles, which is not convenient for observing the material situation. Moreover, the air chute is prone to air leakage and material leakage due to material scouring and wear, that is, cold air condenses and caking occurs when it meets high-temperature materials, resulting in blockage of the chute transportation. Especially in the case of long-distance transportation, the location of the fault point requires the staff to check section by section, which is time-consuming and laborious. Summary of the Invention

[0004] The purpose of the present invention is to provide an on-line continuous monitoring device and method for the gas-solid two-phase flow state in an air chute, and to solve the technical problems of low working efficiency, time-consuming and laborious in the prior art.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An on-line continuous monitoring device for the gas-solid two-phase flow state in an air chute, characterized in that it includes a capacitance probe measurement unit arranged at intervals on the air chute, a purging pipeline corresponding to each group of capacitance probe measurement units, and a PLC automatic control system for overall control of the entire device. A purging pipeline automatic switch valve is provided on the purging pipeline; the PLC automatic control system receives signals from the capacitance probe measurement unit and cleans the capacitance probe by controlling the opening and closing of the purging pipeline automatic switch valve;

[0007] The capacitance probe measurement unit includes at least three groups of capacitance probe assemblies arranged in parallel. Each group of capacitance probe assemblies includes a fixed capacitor and a capacitance probe connected in series. The circuits on both sides of the fixed capacitor are electrically connected to the positive and negative electrodes of a rectifier amplifier respectively. The rectifier amplifier of each group of capacitance probe assemblies is also electrically connected to a multi-channel rectifier filter. After rectifying the amplitude-modulated signal output by the rectifier amplifier, the output signal is accessed into the PLC automatic control system through serial communication or USB port communication, and is displayed on the display after being analyzed and processed in the PLC automatic control system.

[0008] Further preferably, the capacitance probe includes a core and a protective layer wrapped outside the core. The protective layer includes an inner shielding layer, an insulating layer and an outer sleeve wrapped around the core in sequence from inside to outside. The end of the core extending out of the protective layer is the probe detection part, and epoxy resin for sealing the protective layer is provided outside the end of the protective layer and outside the core.

[0009] Further, the capacitance probe is vertically inserted into the air chute upper housing from the air chute, and is fixed to the air chute through a pipe joint.

[0010] Further, the capacitance probes of the capacitance probe measurement unit increase in sequence, and the probe detection parts of different capacitance probes are located in the upper, middle and lower parts of the air chute respectively.

[0011] In addition, the PLC automatic control system includes an execution unit for controlling an automatic switch valve, a data processing unit for processing the input data of the capacitance probe measurement unit, and a decision control system for overall controlling the execution unit and the data processing unit. The display is connected to the decision control system for control.

[0012] More preferably, the outlet of the purging pipeline is aligned with the capacitance probe for cleaning the probe head and maintaining the accuracy of detection data.

[0013] A working method of an on-line continuous monitoring device for the gas-solid two-phase flow state in an air chute, characterized by including the following steps:

[0014] Step 1: Working preparation: The air chute is not working, the material transportation has not started, the capacitance probe contacts the air, the capacitance value is converted into a voltage signal by the capacitance probe measurement unit, and is transmitted to the data processing unit in the PLC automatic control system. After being processed, it is displayed on the display as a voltage straight line with a value of 0v.

[0015] Step 2: Continuous Detection Start: The air chute starts to work. If the fluidized gas and powder are well mixed at the position where the capacitance probe is located, and the gas-solid fluid moves smoothly, the capacitance value fluctuates over time. The capacitance value is converted into a voltage signal by the capacitance probe measurement unit and transmitted to the data processing unit in the PLC automatic control system. After data processing, it is displayed on the monitor as a voltage curve, with the value fluctuating between 0V and the maximum value.

[0016] If the capacitance probe touches a solid lump, the capacitance value is converted into a voltage signal by the capacitance probe measurement unit and transmitted to the data processing unit in the PLC automatic control system. After data processing, it is displayed on the monitor as a voltage straight line, with the value being the maximum value of the voltage.

[0017] Step 3: Purge Work: The voltage value continuously shows the maximum value, and the probe head of the capacitance probe is blocked. The operator controls the automatic switch valve of the purge pipeline on the purge pipeline through the PLC automatic control system to open and clean the probe head. After cleaning, the voltage value transmitted back by the probe head should be a curve, with the value fluctuating between 0V and the maximum value.

[0018] Step 4: Manual Maintenance: After purging in Step 3, if the voltage value transmitted back by the capacitance probe is still a straight line and the value is the maximum value of the voltage, it means that the lump blockage still exists at that place. The on-site operator opens the air chute for maintenance. After the maintenance is completed, the voltage curve shows a continuous fluctuation value between 0V and the maximum value.

[0019] More preferably, in Step 3, the PLC automatic control system regularly opens the automatic switch valve of the purge pipeline on the purge pipeline to purge the probe head.

[0020] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0021] The present invention proposes an on-line continuous monitoring device and method for the gas-solid two-phase flow state in the air chute. The capacitance probe is used to monitor the composition distribution of the gas-solid fluid at a fixed point in the air chute in real time and on-line. The detection data is automatically returned to the PLC automatic control system, which is convenient for the operator to timely discover the fault situation and take measures manually / automatically. The device has a reasonable structure, is simple to install, easy to maintain, has accurate signals and high precision, can accurately judge the gas-solid two-phase flow state in the air chute, ensures the long-term safe and stable operation of the device, and promotes the economic operation of the power plant.

[0022] The present invention facilitates the operator to monitor the movement state and composition distribution of the gas-solid fluid inside the air chute in real time. When the powder material caking blocks the chute, according to the voltage diagram displayed on the monitor, the fault site can be accurately pointed out, eliminating the need for manual troubleshooting and saving maintenance time. The PLC automatic control system can regularly open the automatic switch valve on the purge pipeline to purge the capacitance probe to maintain the accuracy of the detection data. It has the characteristics of safety and applicability, and has good promotion and practical value. After extensive promotion and application, it will generate good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a structural block diagram of the monitoring device related to the present invention;

[0024] Figure 2 is a schematic distribution structure diagram of the capacitance probe measurement unit related to the present invention in the air chute;

[0025] Figure 3 is a circuit connection diagram of the capacitance probe measurement unit related to the present invention;

[0026] Figure 4 is a fixed diagram of the capacitance probe and the pipe joint related to the present invention;

[0027] Figure 5 is a schematic structural diagram of the capacitance probe related to the present invention.

[0028] Reference numerals: 1 - air chute; 2 - purge pipeline; 3 - automatic switch valve of the purge pipeline; 4 - fixed capacitor; 5 - capacitance probe; 51 - needle core; 52 - inner shielding layer; 53 - insulating layer; 54 - outer sleeve; 55 - epoxy resin; 56 - pipe joint; 6 - rectifying amplifier; 7 - multi-channel rectifying filter; 8 - execution unit; 9 - data processing unit; 10 - decision control system; 11 - monitor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the technical means, innovative features, achieved purposes and effects of the present invention easy to understand, the present invention is further described below.

[0030] The embodiments described herein are specific specific embodiments of the present invention for illustrating the concept of the present invention, and are all explanatory and exemplary, and should not be construed as limiting the embodiments of the present invention and the scope of the present invention. Except for the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of the present application, and these technical solutions include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0031] An on-line continuous monitoring device for the gas-solid two-phase flow state in the air chute, such as Figure 2and 3 As shown in combination, it includes a capacitance probe measurement unit spaced on the air chute 1, a purging pipeline 2 correspondingly arranged for each group of capacitance probe measurement units, and a PLC automatic control system for overall control of the entire device. An automatic switch valve 3 for the purging pipeline is provided on the purging pipeline 2. For the convenience of purging, as Figure 1 shown, the PLC automatic control system specifically includes an execution unit 8 for controlling the automatic switch valve, a data processing unit 9 for processing the input data of the capacitance probe measurement unit, and a decision control system 10 for overall control of the execution unit 8 and the data processing unit 9. The display 11 is connected to the decision control system 10 for control. The data processing unit 9 of the PLC automatic control system receives signals from the capacitance probe measurement unit and controls the opening and closing of the automatic switch valve 3 of the purging pipeline through the execution unit 8 to clean the capacitance probe 5.

[0032] The capacitance probe measurement unit includes at least three groups of capacitance probe assemblies arranged in parallel. A number of groups of capacitance probe assemblies of each capacitance probe measurement unit are powered by a regulated power supply. As Figure 3 shown, each group of capacitance probe assemblies includes a fixed capacitor 4 and a capacitance probe 5 connected in series through a zero-adjusting circuit. The circuits on both sides of the fixed capacitor 4 are respectively electrically connected to the positive and negative electrodes of a rectifier amplifier 6. The rectifier amplifier 6 of each group of capacitance probe assemblies is also electrically connected to a multi-channel rectifier filter 7. After the multi-channel rectifier filter 7 rectifies the amplitude-modulated signal output by the rectifier amplifier 6, the output signal is connected to the PLC automatic control system through serial port communication or USB port communication. After analysis and processing in the PLC automatic control system, it is displayed on the display 11; as Figure 5 shown, the capacitance probe 5 specifically includes a probe core 51 and a protective layer wrapped around the probe core 51. The protective layer includes an inner shielding layer 52, an insulating layer 53, and an outer sleeve 54 sequentially wrapped around the probe core 51 from the inside to the outside. The end of the probe core 51 extending out of the protective layer is a probe detection part. Epoxy resin 55 for sealing the protective layer is provided outside the end of the protective layer and the probe core 51. The capacitance probe 5 is vertically inserted from the upper shell of the air chute 1 and fixed to the air chute 1 through a pipe joint 56. The outlet of the purging pipeline 2 is arranged opposite to the capacitance probe 5 to clean the probe head and maintain the accuracy of the detection data.

[0033] Taking the example that each capacitance probe measurement unit includes three groups of capacitance probe assemblies arranged in parallel, the capacitance probes 5 of the capacitance probe measurement unit increase in sequence. The probe detection parts of different capacitance probes 5 are respectively located at the upper, middle, and lower parts of the air chute 1. Generally, as Figure 4As shown, three capacitance probes 5 can supply a pipe joint 56, and the pipe joint 56 and the wall of the air chute 1 are fixed by means including but not limited to welding. After each group of capacitance probe measurement units rectify the amplitude-modulated signals output by three rectifier amplifiers 6 through a multi-channel rectifier filter 7, the output signals are connected to the data processing unit 9 of the PLC automatic control system through serial communication or USB communication. After data processing, they are displayed on the display 11. On the display 11, a graph showing the voltage change at each group of capacitance probe measurement units is displayed. One can manually decide whether to open the automatic switch valve 3 of the purge pipeline according to the graph results, or when it is at the critical value, the PLC automatic control system automatically controls the opening or closing of the automatic switch valve 3 of the purge pipeline.

[0034] A working method for an on-line continuous monitoring device of the gas-solid two-phase flow state in an air chute, characterized in that:

[0035] Step 1: Working preparation: The air chute is not working, the material transportation has not started, the capacitance probe 5 contacts the air, the capacitance value is converted into a voltage signal through the capacitance probe measurement unit, and is transmitted to the data processing unit in the PLC automatic control system. After data processing, it is displayed on the display, showing a voltage straight line with a value of 0V.

[0036] Step 2: Start of continuous detection: The air chute starts to work. If the fluidizing gas and the powder are mixed relatively evenly at the position where the capacitance probe 5 is located and the gas-solid fluid moves smoothly, the capacitance value fluctuates with time. The capacitance value is converted into a voltage signal through the capacitance probe measurement unit and is transmitted to the data processing unit 9 in the PLC automatic control system. After data processing, it is displayed on the display 11, showing a voltage curve with values fluctuating between 0V and the maximum value;

[0037] If the capacitance probe 5 contacts a solid lump, the capacitance value is converted into a voltage signal through the capacitance probe measurement unit and is transmitted to the data processing unit 9 in the PLC automatic control system. After data processing, it is displayed on the display 11, showing a voltage straight line with a value of the maximum voltage;

[0038] Step 3: Purge work: The voltage value continuously shows the maximum value, the probe head of the capacitance probe is blocked, and the operator controls the opening of the automatic switch valve 3 of the purge pipeline 2 on the purge pipeline through the PLC automatic control system to clean the probe head. After cleaning, the voltage value transmitted back by the probe head should be a curve with values fluctuating between 0V and the maximum value; In this step, the PLC automatic control system can be set to regularly open the automatic switch valve 3 of the purge pipeline 2 to purge the probe head.

[0039] Step 4: Manual inspection: After purging in Step 3, if the voltage value transmitted back by the capacitance probe 5 is still a straight line and the value is the maximum voltage value, it indicates that caking and blockage still exist at that location. The on-site operators should open the air chute for inspection. After the inspection is completed, the voltage curve shows a continuous fluctuation value between 0V and the maximum value.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An on-line continuous monitoring device for the gas-solid two-phase flow state in an air chute, characterized in that: It includes a capacitance probe measurement unit spaced on the air chute (1), a purging pipeline (2) arranged corresponding to each group of capacitance probe measurement units, and a PLC automatic control system for overall control of the entire device. A purging pipeline automatic switch valve (3) is provided on the purging pipeline (2); the PLC automatic control system receives signals from the capacitance probe measurement unit and cleans the capacitance probe (5) by controlling the opening and closing of the purging pipeline automatic switch valve (3). The capacitance probe measurement unit includes at least three groups of capacitance probe assemblies arranged in parallel. Each group of capacitance probe assemblies includes a fixed capacitor (4) and a capacitance probe (5) connected in series. The circuits on both sides of the fixed capacitor (4) are electrically connected to the positive and negative electrodes of a rectifier amplifier (6) respectively. The rectifier amplifier (6) of each group of capacitance probe assemblies is also electrically connected to a multi-channel rectifier filter (7). After the multi-channel rectifier filter (7) rectifies the amplitude-modulated signal output by the rectifier amplifier (6), the output signal is accessed into the PLC automatic control system through serial communication or USB port communication. After analysis and processing in the PLC automatic control system, it is displayed on a display (11). The PLC automatic control system includes an execution unit (8) for controlling the automatic switch valve, a data processing unit (9) for processing the input data of the capacitance probe measurement unit, and a decision control system (10) for overall control of the execution unit (8) and the data processing unit (9). The display (11) is controlled and connected to the decision control system (10). The capacitance probe (5) vertically inserts from the upper shell of the air chute (1) and is fixed to the air chute (1) through a pipe joint (56); the capacitance probes (5) of the capacitance probe measurement unit increase in sequence; the probe detection parts of different capacitance probes (5) are respectively located in the upper, middle, and lower parts of the air chute (1); the outlet of the purging pipeline (2) is arranged opposite to the capacitance probe (5).

2. The on-line continuous monitoring device for the gas-solid two-phase flow state in the air chute according to claim 1, characterized in that: The capacitance probe (5) includes a needle core (51) and a protective layer wrapped outside the needle core (51).

3. The on-line continuous monitoring device for the gas-solid two-phase flow state in the air chute according to claim 2, characterized in that: The protective layer includes an inner shielding layer (52), an insulating layer (53), and an outer sleeve (54) sequentially wrapped on the needle core (51) from the inside to the outside. The end of the needle core (51) extending out of the protective layer is the probe detection part. Epoxy resin (55) for sealing the protective layer is provided outside the end of the protective layer and the needle core (51).

4. The working method of the on-line continuous monitoring device for the gas-solid two-phase flow state in the air chute according to any one of claims 1 to 3, characterized in that: Step 1: Working preparation: The air chute is not working, the material transportation has not started, the capacitance probe (5) contacts the air, the capacitance value is converted into a voltage signal by the capacitance probe measurement unit and transmitted to the data processing unit (9) in the PLC automatic control system. After data processing, it is displayed on the display (11), showing a voltage straight line with a value of 0v. Step 2: Continuous Detection Start: The air chute starts to work. If the fluidizing gas and powder are mixed evenly at the location where the capacitance probe (5) is located, and the gas-solid fluid movement is smooth and unobstructed, the capacitance value fluctuates over time. The capacitance value is converted into a voltage signal by the capacitance probe measurement unit and transmitted to the data processing unit (9) in the PLC automatic control system. After data processing, it is displayed on the monitor (11) as a voltage curve, and the value fluctuates between 0v and the maximum value; If the capacitance probe (5) touches a solid lump, the capacitance value is converted into a voltage signal by the capacitance probe measurement unit and transmitted to the data processing unit (9) in the PLC automatic control system. After data processing, it is displayed on the monitor (11) as a voltage straight line, and the value is the maximum value of the voltage; Step 3: Purge Work: When the voltage value continuously shows the maximum value, it is judged that the probe head of the capacitance probe is blocked. The operator controls the automatic purge pipeline valve (3) on the purge pipeline (2) to open through the PLC automatic control system to clean the probe head. After cleaning, the voltage value transmitted back by the capacitance probe (5) should be a curve, and the value fluctuates between 0v and the maximum value; Step 4: Manual Maintenance: After purging in Step 3, if the voltage value transmitted back by the capacitance probe (5) is still a straight line and the value is the maximum voltage value, it means that the blockage of the lump still exists. The on-site operator opens the air chute for maintenance. After the maintenance is completed, the voltage curve shows a continuous fluctuation value between 0v and the maximum value.

5. The working method of the on-line continuous monitoring device for the gas-solid two-phase flow state in the air chute according to claim 4, characterized in that: In Step 3, the PLC automatic control system regularly opens the automatic purge pipeline valve (3) on the purge pipeline (2) to purge the probe head.

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