Clean coal ash content automatic detection system

Abstract

The invention relates to the technical field of clean coal ash detection, and proposes a clean coal ash automatic detection system, including a driving circuit, the driving circuit including a transistor Q1, a transistor Q2, a switch tube Q3, a resistor R7, an ash measuring probe P1, an operational amplifier U1 and a switch tube Q4, the base of the transistor Q1 is connected to the first output end of the main control unit, the collector of the transistor Q2 is connected to a 12V power supply, the emitter of the transistor Q2 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is connected to the control end of the switch tube Q3, the first end of the switch tube Q3 is connected to the 12V power supply through the ash measuring probe P1, the second end of the switch tube Q3 is grounded through the resistor R7, the second end of the switch tube Q3 is connected to the in-phase input end of the operational amplifier U1, the inverting input end of the operational amplifier U1 is grounded, the output end of the operational amplifier U1 is connected to the control end of the switch tube Q4, the first end of the switch tube Q4 is connected to the base of the transistor Q1, and the second end of the switch tube Q4 is grounded. Through the above technical scheme, the problem of poor clean coal ash detection accuracy in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of clean coal ash content detection, and in particular to an automatic clean coal ash content detection system. Background Art

[0002] The ash content of clean coal is one of the main bases for settlement between coal preparation plants and users, and is also an important indicator for assessing the quality of coal products. Therefore, accurate determination of its content is of great significance. Traditional ash content detection is mainly determined by manual rapid ash determination method, which has problems such as data lag and low efficiency and cannot guide production in time. With the development and progress of society, the ash content of clean coal is currently based on the real-time measurement data of the ash meter as the feedback value to control the ash content of coal preparation, solving the problems of data lag and low efficiency.

[0003] An ash meter is an instrument for detecting radioactive rays. Radioactive elements are ubiquitous in nature. Coal also contains radioactive trace elements. The natural λ rays emitted by minerals in coal are used to quickly detect the ash content. During the detection process of the ash meter, the scintillator inside it is energized. The natural λ rays emitted by the coal can cause the scintillator to glow. The light emitted by the scintillator is photoelectrically converted to obtain a corresponding electrical signal. The higher the ash content of the coal being tested, the stronger the luminescence of the scintillator, and the higher the voltage after photoelectric conversion. Therefore, the stability of the scintillator directly affects the detection accuracy of the clean coal ash content. The existing ash meter has deviations in the detection of clean coal ash content due to different detection environments, resulting in poor detection accuracy of clean coal ash content. Summary of the invention

[0004] The invention provides an automatic detection system for clean coal ash content, which solves the problem of poor detection accuracy of clean coal ash content in the prior art.

[0005] The technical solution of the present invention is as follows:

[0006] The clean coal ash content automatic detection system comprises a main control unit and a drive circuit, wherein the drive circuit is connected to the main control unit, and the drive circuit comprises a resistor R3, a transistor Q1, a transistor Q2, a resistor R4, a switch tube Q3, a resistor R7, an ash measuring probe P1, an operational amplifier U1, a resistor R28, a resistor R6, a resistor R8, a resistor R9, a switch tube Q4 and a resistor R5.

[0007] The first end of the resistor R3 is connected to the first output end of the main control unit, the second end of the resistor R3 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to a 12V power supply, the emitter of the transistor Q2 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is connected to the control end of the switch tube Q3 through the resistor R4, the collector of the transistor Q1 is grounded, the first end of the switch tube Q3 is connected to the first end of the gray measuring probe P1, and the second end of the gray measuring probe P1 is connected to the control end of the switch tube Q3. The first end of the switch tube Q4 is connected to the 12V power supply, the second end of the switch tube Q3 is grounded through the resistor R7, the second end of the switch tube Q3 is connected to the non-inverting input end of the operational amplifier U1 through the resistor R28, the inverting input end of the operational amplifier U1 is grounded through the resistor R6, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R8, the output end of the operational amplifier U1 is connected to the control end of the switch tube Q4 through the resistor R9, the first end of the switch tube Q4 is connected to the base of the transistor Q1 through the resistor R5, and the second end of the switch tube Q4 is grounded.

[0008] Furthermore, the driving circuit in the present invention also includes a resistor R1, an optocoupler U2 and a resistor R3, the first input end of the optocoupler U2 is connected to the first output end of the main control unit through the resistor R1, the second input end of the optocoupler U2 is grounded, the first output end of the optocoupler U2 is connected to a 5V power supply through the resistor R2, and the second output end of the optocoupler U2 is connected to the first end of the resistor R3.

[0009] Furthermore, the present invention also includes a delay circuit, which includes a resistor R10, a capacitor C3, a NOT gate U3, a resistor R11, a switch tube Q5, a resistor R12, a switch tube Q6, a resistor R14, a resistor R15, a resistor R16 and a switch tube Q7.

[0010] The first end of the resistor R10 is connected to a 5V power supply, the second end of the resistor R10 is grounded through the capacitor C3, the second end of the resistor R10 is connected to the input end of the NOT gate U3, the output end of the NOT gate U3 is connected to the control end of the switch tube Q5 through the resistor R11, the first end of the switch tube Q5 is connected to the 5V power supply, the second end of the switch tube Q5 is grounded, the first end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the resistor R13, the first end of the switch tube Q6 is connected to the 5V power supply, the second end of the switch tube Q6 is connected to the -5V power supply through the resistor R15, the second end of the switch tube Q6 is grounded through the resistor R16, the second end of the switch tube Q6 is connected to the control end of the switch tube Q7 through the resistor R14, the first end of the switch tube Q7 is connected to the second end of the gray measuring probe P1, and the second end of the switch tube Q7 is grounded.

[0011] Furthermore, the present invention also includes a photoelectric detection circuit, which includes a photoelectric receiving tube U4, a resistor R17, a capacitor C5, an operational amplifier U6, a resistor R19, a resistor R20 and a resistor R21. The cathode of the photoelectric receiving tube U4 is connected to a 5V power supply, the anode of the photoelectric receiving tube U4 is grounded through the resistor R17, the anode of the photoelectric receiving tube U4 is connected to the first end of the capacitor C5, the second end of the capacitor C5 is connected to the non-inverting input end of the operational amplifier U6, the inverting input end of the operational amplifier U6 is grounded through the resistor R19, the inverting input end of the operational amplifier U6 is connected to the Vref1 reference voltage through the resistor R21, the output end of the operational amplifier U6 is connected to the inverting input end of the operational amplifier U6 through the resistor R20, and the output end of the operational amplifier U6 is connected to the first input end of the main control unit.

[0012] Furthermore, the photoelectric detection circuit in the present invention also includes a resistor R18 and an operational amplifier U5, the first end of the resistor R18 is connected to the anode of the photoelectric receiving tube U4, the second end of the resistor R18 is connected to the non-inverting input terminal of the operational amplifier U5, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U5, and the output terminal of the operational amplifier U5 is connected to the first end of the capacitor C5.

[0013] Furthermore, the present invention also includes a filtering circuit, which includes a capacitor C6, a resistor R22, an op amp U7, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a capacitor C7, an op amp U8 and a resistor R27, wherein a first end of the capacitor C6 is connected to an output end of the op amp U6, a second end of the capacitor C6 is grounded through the resistor R22, a second end of the capacitor C6 is connected to a non-inverting input end of the op amp U7, an inverting input end of the op amp U7 is grounded through the resistor R23, and The output end of the operational amplifier U7 is connected to the inverting input end of the operational amplifier U7 through the resistor R24, the output end of the operational amplifier U7 is connected to the non-inverting input end of the operational amplifier U8 through the resistor R25, the non-inverting input end of the operational amplifier U8 is grounded through the capacitor C7, the inverting input end of the operational amplifier U8 is connected to the Vref2 reference power supply through the resistor R26, the output end of the operational amplifier U8 is connected to the inverting input end of the operational amplifier U8 through the resistor R27, and the output end of the operational amplifier U8 is connected to the main control unit.

[0014] The working principle and beneficial effects of the present invention are:

[0015] In the present invention, the natural λ rays emitted by minerals in coal are used to quickly detect the ash content therein. During the detection process, the natural λ rays emitted by the coal can cause the scintillator in the ash measuring probe P1 to emit light. The driving circuit is used to control the stability of the current flowing through the ash measuring probe P1, ensuring that the ash measuring probe P1 can work stably and reliably during the process of detecting the ash content of clean coal.

[0016] Specifically, the working principle of the driving circuit is as follows: when the clean coal ash detector detects the clean coal ash content, the main control unit outputs a PWM control signal, which is sent to a push-pull circuit composed of transistors Q1 and Q2. The push-pull circuit is used to improve the driving ability of the PWM control signal. When the PWM control signal is at a high level, the transistor Q1 is turned off, the transistor Q2 is turned on, the emitter of the transistor Q1 is at a high level, the switch tube Q3 is turned on, and the ash probe P1 is powered on. At this time, the ash probe P1 can detect the natural λ rays emitted by the minerals in the coal, thereby causing the scintillator in the ash probe P1 to emit light; when the PWM control signal is at a low level, the transistor Q1 is turned on, the transistor Q2 is turned off, the emitter of the transistor Q1 is at a low level, the switch tube Q3 is turned off, and the ash probe P1 is powered off until the PWM control signal becomes high again, and the ash probe P1 is powered on again, forming a cycle in sequence.

[0017] When the switch tube Q3 is turned on, current flows through the resistor R7, and a voltage is generated on the resistor R7. The voltage on the resistor R7 is collected and sent to the non-inverting input terminal of the operational amplifier U1. The operational amplifier U1 constitutes an amplification circuit. When the current flowing through the ash measuring probe P1 increases due to changes in the detection environment or other reasons during the detection of the ash content of the clean coal, the voltage division on the resistor R7 increases, so the voltage output by the operational amplifier U1 increases, the current at the control end of the switch tube Q4 increases, and the current at the first end of the switch tube Q4 increases. Therefore, the voltage division of the resistor R5 increases, and the base voltage of the transistor Q1 decreases, resulting in a decrease in the voltage at the control end of the switch tube Q3, thereby resulting in a decrease in the current at the first end of the switch tube Q3; similarly, when the current flowing through the ash measuring probe P1 decreases, the voltage at the control end of the switch tube Q3 increases, and finally the current flowing through the ash measuring probe P1 increases.

[0018] In the present invention, the current flowing through the ash measuring probe P1 can be kept stable, so that the ash measuring probe P1 can work in a constant current state, thereby improving the stability of the ash measuring probe P1 during operation and ensuring that the luminescence of the scintillator of the ash measuring probe P1 is stable during operation, thereby improving the detection accuracy of the ash content in the clean coal.

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a circuit diagram of a driving circuit in the present invention;

[0021] Figure 2 is a circuit diagram of the delay circuit in the present invention;

[0022] Figure 3 is a circuit diagram of the photoelectric detection circuit in the present invention;

[0023] Figure 4 4 is a circuit diagram of the filter circuit in the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] like Figure 1As shown, this embodiment proposes an automatic detection system for clean coal ash content, including a main control unit and a drive circuit, the drive circuit is connected to the main control unit, the drive circuit includes a resistor R3, a transistor Q1, a transistor Q2, a resistor R4, a switch tube Q3, a resistor R7, an ash measuring probe P1, an operational amplifier U1, a resistor R28, a resistor R6, a resistor R8, a resistor R9, a switch tube Q4 and a resistor R5, a first end of the resistor R3 is connected to a first output end of the main control unit, a second end of the resistor R3 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to a 12V power supply, the emitter of the transistor Q2 is connected to the emitter of the transistor Q1, and the The emitter is connected to the control end of the switch tube Q3 through the resistor R4, the collector of the transistor Q1 is grounded, the first end of the switch tube Q3 is connected to the first end of the gray measuring probe P1, the second end of the gray measuring probe P1 is connected to the 12V power supply, the second end of the switch tube Q3 is grounded through the resistor R7, the second end of the switch tube Q3 is connected to the in-phase input end of the operational amplifier U1 through the resistor R28, the inverting input end of the operational amplifier U1 is grounded through the resistor R6, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R8, the output end of the operational amplifier U1 is connected to the control end of the switch tube Q4 through the resistor R9, the first end of the switch tube Q4 is connected to the base of the transistor Q1 through the resistor R5, and the second end of the switch tube Q4 is grounded.

[0027] The clean coal ash detector uses the natural λ rays emitted by minerals in coal to quickly detect the ash content therein. During the detection process, the ash probe P1 is powered on and used to receive the λ rays. The natural λ rays emitted in the coal can cause the scintillator to emit light. The light emitted by the scintillator is photoelectrically converted to obtain a corresponding electrical signal, and the clean coal ash content is determined by the electrical signal. In actual application, the power supply of the ash probe P1 will change with the changes in the environment, resulting in unstable power supply of the ash probe P1, affecting the light emission of the scintillator, resulting in inaccurate photoelectric detection results, and thus resulting in poor detection accuracy of the clean coal ash content. For this reason, in this embodiment, a stable driving current is provided by the driving circuit to ensure that the ash probe P1 works in a stable state.

[0028] Specifically, the working principle of the driving circuit is as follows: when the clean coal ash detector detects the clean coal ash content, the main control unit outputs a PWM control signal, which is sent to the base of the transistor Q1 and the transistor Q2 after passing through the resistor R3. The transistor Q1 and the transistor Q2 form a push-pull circuit to improve the driving ability of the PWM control signal. When the PWM control signal is at a high level, the transistor Q1 is turned off, the transistor Q2 is turned on, the emitter of the transistor Q1 is at a high level, the switch tube Q3 is turned on, and the ash probe P1 is powered on. At this time, the ash probe P1 can detect the natural λ rays emitted by the minerals in the coal, thereby causing the scintillator in the ash probe P1 to emit light; when the PWM control signal is at a low level, the transistor Q1 is turned on, the transistor Q2 is turned off, the emitter of the transistor Q1 is at a low level, the switch tube Q3 is turned off, and the ash probe P1 is powered off until the PWM control signal becomes high again, and the ash probe P1 is powered on again, forming a cycle in sequence.

[0029] When the switch tube Q3 is turned on, the current flows through the resistor R7, and a voltage is generated on the resistor R7. The voltage on the resistor R7 is collected and sent to the non-inverting input terminal of the operational amplifier U1. The operational amplifier U1 forms an amplification circuit and sends the amplified voltage value to the control terminal of the switch tube Q4. The switch tube Q4 is turned on. At this time, part of the base voltage of the transistor Q1 passes through the resistor R5 and the switch tube Q4 to the ground. When the current of the ash measuring probe P1 is stable during the detection of the clean coal ash content, the voltage output by the operational amplifier U1 remains stable; when the current flowing through the ash measuring probe P1 increases due to changes in the detection environment or other reasons during the detection of the clean coal ash content, the voltage divided by the resistor R7 increases, so the voltage output by the operational amplifier U1 increases, the current at the control end of the switch tube Q4 increases, and the current at the first end of the switch tube Q4 increases. Therefore, the voltage divided by the resistor R5 increases, and the base voltage of the transistor Q1 decreases, resulting in a decrease in the voltage at the control end of the switch tube Q3, thereby causing the switch tube Q 3 decreases; when the current flowing through the ash measuring probe P1 decreases, the output voltage of the operational amplifier U1 decreases, the control end current of the switch tube Q4 decreases, the first end current of the switch tube Q4 decreases, the voltage division on the resistor R5 decreases, the base voltage of the transistor Q1 increases, and the control end voltage of the switch tube Q3 increases, and finally the current flowing through the ash measuring probe P1 becomes larger; thereby, the current flowing through the ash measuring probe P1 remains stable, and the ash measuring probe P1 works in a constant current state, which improves the working stability of the ash measuring probe P1 and improves the detection accuracy of the ash content in the clean coal.

[0030] In this embodiment, an N-channel enhancement type field effect transistor is used as the switch tube Q3; and an NPN type transistor is used as the switch tube Q4.

[0031] like Figure 1As shown, in this embodiment, the driving circuit also includes a resistor R1, an optocoupler U2 and a resistor R3, the first input end of the optocoupler U2 is connected to the first output end of the main control unit through the resistor R1, the second input end of the optocoupler U2 is grounded, the first output end of the optocoupler U2 is connected to a 5V power supply through the resistor R2, and the second output end of the optocoupler U2 is connected to the first end of the resistor R3.

[0032] In this embodiment, the PWM control signal output by the main control unit may interfere with the signal between the subsequent drive circuits. Since the voltage of the drive circuit is greater than the voltage amplitude of the PWM control signal output by the main control unit, the main control unit may be damaged. For this reason, in this embodiment, an optical coupler U2 is added between the main control unit and the resistor R3. The optical coupler U2 constitutes an isolation circuit to prevent mutual interference between signals and protect the main control unit. When the PWM control signal is at a high level, the optical coupler U2 is turned on, and when the PWM control signal is at a low level, the optical coupler U2 is turned off.

[0033] like Figure 2 As shown, the present embodiment also includes a delay circuit, which includes a resistor R10, a capacitor C3, a NOT gate U3, a resistor R11, a switch tube Q5, a resistor R12, a switch tube Q6, a resistor R14, a resistor R15, a resistor R16 and a switch tube Q7. The first end of the resistor R10 is connected to a 5V power supply, and the second end of the resistor R10 is grounded through the capacitor C3. The second end of the resistor R10 is connected to the input end of the NOT gate U3, and the output end of the NOT gate U3 is connected to the control end of the switch tube Q5 through the resistor R11. The first end of the switch tube Q5 is connected to the 5V power supply, and the second end of the switch tube Q5 is grounded. The first end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the resistor R13. The first end of the switch tube Q6 is connected to the 5V power supply, and the second end of the switch tube Q6 is connected to the -5V power supply through the resistor R15. The second end of the switch tube Q6 is grounded through the resistor R16. The second end of the switch tube Q6 is connected to the control end of the switch tube Q7 through the resistor R14. The first end of the switch tube Q7 is connected to the second end of the gray measuring probe P1, and the second end of the switch tube Q7 is grounded.

[0034] When the clean coal ash content is detected by the clean coal ash detector, a momentary large current will be generated and added to the two ends of the ash measuring probe P1 at the moment of power-on. This large current will cause an impact on the ash measuring probe P1, which will reduce the service life of the ash measuring probe P1 in the long run. For this reason, this embodiment adds a delay circuit to prevent the ash measuring probe P1 from causing an impact at the moment of power-on.

[0035] Specifically, the working principle of the delay circuit is as follows: the delay circuit is connected in parallel to the second end of the ash measuring probe P1, and the resistor R10 and the capacitor C3 form a delay circuit. At the moment when the circuit is powered on, the NOT gate U3 outputs a high level, the switch tube Q5 is turned on, and the first end of the switch tube Q5 is a low level. The switch tube Q6 is turned on, and the second end of the switch tube Q6 is a high level. Therefore, the switch tube Q7 is also turned on. Therefore, the 12V power supply in the drive circuit reaches the ground after the switch tube Q7; after a period of time, the output of the NOT gate U3 becomes a low level, the switch tube Q5 is turned off, and the switch tube Q6 is also turned off. At this time, the control end of the switch tube Q7 is a negative voltage, and the switch tube Q7 is turned off. At this time, the 12V power supply is added to the ash measuring probe P1, and the ash measuring probe P1 starts to work. The values ​​of the resistor R10 and the capacitor C3 determine the time when the ash measuring probe P1 starts to work.

[0036] In this embodiment, an NPN transistor is used as the switch tube Q5; a PNP transistor is used as the switch tube Q6; and an N-channel depletion field effect transistor is used as the switch tube Q7.

[0037] like Figure 3 As shown, this embodiment also includes a photoelectric detection circuit, which includes a photoelectric receiving tube U4, a resistor R17, a capacitor C5, an operational amplifier U6, a resistor R19, a resistor R20 and a resistor R21. The cathode of the photoelectric receiving tube U4 is connected to a 5V power supply, the anode of the photoelectric receiving tube U4 is grounded through the resistor R17, the anode of the photoelectric receiving tube U4 is connected to the first end of the capacitor C5, the second end of the capacitor C5 is connected to the in-phase input terminal of the operational amplifier U6, the inverting input terminal of the operational amplifier U6 is grounded through the resistor R19, the inverting input terminal of the operational amplifier U6 is connected to the Vref1 reference voltage through the resistor R21, the output terminal of the operational amplifier U6 is connected to the inverting input terminal of the operational amplifier U6 through the resistor R20, and the output terminal of the operational amplifier U6 is connected to the first input terminal of the main control unit.

[0038] When the ash measuring probe P1 works normally, the natural λ rays emitted from the coal can cause the scintillator in the ash measuring probe P1 to emit light. By performing photoelectric conversion on the light emitted by the scintillator, a corresponding electrical signal is obtained, and the ash content of the clean coal is determined by the electrical signal. The photoelectric detection circuit is used to convert the light emitted by the scintillator into an electrical signal.

[0039] Specifically, the working principle of the photoelectric detection circuit is as follows: the photoelectric receiving tube U4 is used to receive the light signal emitted by the scintillator, and convert the received light signal into an electrical signal for output. The electrical signal is coupled by the capacitor C5 and sent to the non-inverting input terminal of the operational amplifier U6. The operational amplifier U6 constitutes an amplification circuit. Since the electrical signal output by the photoelectric receiving tube U4 is relatively weak, it needs to be amplified by the operational amplifier U6, and finally the amplified voltage signal is sent to the main control unit. The main control unit determines the ash content of the measured clean coal based on the received voltage signal.

[0040] like Figure 3As shown, the photoelectric detection circuit in this embodiment also includes a resistor R18 and an operational amplifier U5, the first end of the resistor R18 is connected to the anode of the photoelectric receiving tube U4, the second end of the resistor R18 is connected to the non-inverting input terminal of the operational amplifier U5, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U5, and the output terminal of the operational amplifier U5 is connected to the first end of the capacitor C5.

[0041] Since the electrical signal output by the photoelectric receiving tube U4 is relatively weak, and the signal causes certain losses during the transmission process, the electrical signal output by the photoelectric receiving tube U4 may not be effectively transmitted. In order to solve this problem, this embodiment adds an operational amplifier U5 between the photoelectric receiving tube U4 and the capacitor C5. The operational amplifier U5 constitutes a follower, thereby improving the signal transmission capability. At the same time, the follower can also play a role in signal isolation.

[0042] like Figure 4 As shown, the present embodiment also includes a filtering circuit, which includes a capacitor C6, a resistor R22, an operational amplifier U7, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a capacitor C7, an operational amplifier U8 and a resistor R27. The first end of the capacitor C6 is connected to the output end of the operational amplifier U6, the second end of the capacitor C6 is grounded through the resistor R22, the second end of the capacitor C6 is connected to the non-inverting input end of the operational amplifier U7, the inverting input end of the operational amplifier U7 is grounded through the resistor R23, the output end of the operational amplifier U7 is connected to the inverting input end of the operational amplifier U7 through the resistor R24, the output end of the operational amplifier U7 is connected to the non-inverting input end of the operational amplifier U8 through the resistor R25, the non-inverting input end of the operational amplifier U8 is grounded through the capacitor C7, the inverting input end of the operational amplifier U8 is connected to the Vref2 reference power supply through the resistor R26, the output end of the operational amplifier U8 is connected to the inverting input end of the operational amplifier U8 through the resistor R27, and the output end of the operational amplifier U8 is connected to the main control unit.

[0043] The photoelectric receiving tube U4 may introduce some interference signals in the process of receiving the optical signal, which will seriously affect the detection accuracy of the clean coal ash content, so it is necessary to filter out these interference signals. Capacitor C6 and resistor R22 form a high-pass filter circuit, and resistor R25 and capacitor C7 form a low-pass filter circuit; the high-pass filter circuit is used to filter out the noise signal in the signal, and the low-pass filter circuit is used to filter out the high-frequency interference signal in the signal. The high-pass filter circuit and the low-pass filter circuit form a band-pass filter circuit, which can well filter out useless interference signals and send useful signals to the main control unit.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Clean coal ash content automatic detection system, characterized in that: It includes a main control unit and a driving circuit, the driving circuit is connected to the main control unit, and the driving circuit includes a resistor R3, a transistor Q1, a transistor Q2, a resistor R4, a switch tube Q3, a resistor R7, an ash measuring probe P1, an operational amplifier U1, a resistor R28, a resistor R6, a resistor R8, a resistor R9, a switch tube Q4 and a resistor R5, The first end of the resistor R3 is connected to the first output end of the main control unit, the second end of the resistor R3 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to a 12V power supply, the emitter of the transistor Q2 is connected to the emitter of the transistor Q1, the emitter of the transistor Q1 is connected to the control end of the switch tube Q3 through the resistor R4, the collector of the transistor Q1 is grounded, the first end of the switch tube Q3 is connected to the first end of the gray measuring probe P1, and the second end of the gray measuring probe P1 is connected to the control end of the switch tube Q3. The first end of the switch tube Q4 is connected to the 12V power supply, the second end of the switch tube Q3 is grounded through the resistor R7, the second end of the switch tube Q3 is connected to the non-inverting input end of the operational amplifier U1 through the resistor R28, the inverting input end of the operational amplifier U1 is grounded through the resistor R6, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R8, the output end of the operational amplifier U1 is connected to the control end of the switch tube Q4 through the resistor R9, the first end of the switch tube Q4 is connected to the base of the triode Q1 through the resistor R5, and the second end of the switch tube Q4 is grounded; The delay circuit includes a resistor R10, a capacitor C3, a NOT gate U3, a resistor R11, a switch tube Q5, a resistor R12, a switch tube Q6, a resistor R14, a resistor R15, a resistor R16 and a switch tube Q7. The first end of the resistor R10 is connected to a 5V power supply, the second end of the resistor R10 is grounded through the capacitor C3, the second end of the resistor R10 is connected to the input end of the NOT gate U3, the output end of the NOT gate U3 is connected to the control end of the switch tube Q5 through the resistor R11, the first end of the switch tube Q5 is connected to the 5V power supply, the second end of the switch tube Q5 is grounded, the first end of the switch tube Q5 is connected to the control end of the switch tube Q6 through the resistor R13, the first end of the switch tube Q6 is connected to the 5V power supply, the second end of the switch tube Q6 is connected to the -5V power supply through the resistor R15, the second end of the switch tube Q6 is grounded through the resistor R16, the second end of the switch tube Q6 is connected to the control end of the switch tube Q7 through the resistor R14, the first end of the switch tube Q7 is connected to the second end of the gray measuring probe P1, and the second end of the switch tube Q7 is grounded; It also includes a photoelectric detection circuit, which includes a photoelectric receiving tube U4, a resistor R17, a capacitor C5, an operational amplifier U6, a resistor R19, a resistor R20 and a resistor R21. The cathode of the photoelectric receiving tube U4 is connected to a 5V power supply, the anode of the photoelectric receiving tube U4 is grounded through the resistor R17, the anode of the photoelectric receiving tube U4 is connected to the first end of the capacitor C5, the second end of the capacitor C5 is connected to the in-phase input end of the operational amplifier U6, the inverting input end of the operational amplifier U6 is grounded through the resistor R19, the inverting input end of the operational amplifier U6 is connected to the Vref1 reference voltage through the resistor R21, the output end of the operational amplifier U6 is connected to the inverting input end of the operational amplifier U6 through the resistor R20, and the output end of the operational amplifier U6 is connected to the first input end of the main control unit.

2. The clean coal ash automatic detection system according to claim 1 is characterized in that: The driving circuit also includes a resistor R1, an optocoupler U2 and a resistor R3, wherein the first input end of the optocoupler U2 is connected to the first output end of the main control unit through the resistor R1, the second input end of the optocoupler U2 is grounded, the first output end of the optocoupler U2 is connected to a 5V power supply through the resistor R2, and the second output end of the optocoupler U2 is connected to the first end of the resistor R3.

3. The clean coal ash automatic detection system according to claim 1 is characterized in that: The photoelectric detection circuit also includes a resistor R18 and an operational amplifier U5, wherein the first end of the resistor R18 is connected to the anode of the photoelectric receiving tube U4, the second end of the resistor R18 is connected to the non-inverting input end of the operational amplifier U5, the output end of the operational amplifier U5 is connected to the inverting input end of the operational amplifier U5, and the output end of the operational amplifier U5 is connected to the first end of the capacitor C5.

4. The clean coal ash automatic detection system according to claim 3 is characterized in that: The filter circuit also includes a filter circuit, which includes a capacitor C6, a resistor R22, an operational amplifier U7, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a capacitor C7, an operational amplifier U8 and a resistor R27. The first end of the capacitor C6 is connected to the output end of the operational amplifier U6, the second end of the capacitor C6 is grounded through the resistor R22, the second end of the capacitor C6 is connected to the non-inverting input end of the operational amplifier U7, the inverting input end of the operational amplifier U7 is grounded through the resistor R23, and the operational amplifier U The output end of the operational amplifier U7 is connected to the inverting input end of the operational amplifier U7 through the resistor R24, the output end of the operational amplifier U7 is connected to the non-inverting input end of the operational amplifier U8 through the resistor R25, the non-inverting input end of the operational amplifier U8 is grounded through the capacitor C7, the inverting input end of the operational amplifier U8 is connected to the Vref2 reference power supply through the resistor R26, the output end of the operational amplifier U8 is connected to the inverting input end of the operational amplifier U8 through the resistor R27, and the output end of the operational amplifier U8 is connected to the main control unit.

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