A paper-feeding method with constant linear velocity for a radioactive aerosol activity monitor

Abstract

The application discloses a paper feeding method with constant linear velocity of a radioactive aerosol activity monitor, and belongs to the technical field of nuclear radiation measuring instruments.The method comprises the following steps: 1, filter paper installation; 2, filter paper feeding; and 3, feeding detection.The motor is controlled by a PLC controller to rotate at a constant linear velocity, so that the filter paper always keeps a constant speed, the stability of the sampling flow in the air path is ensured, and the accuracy of the monitoring result is ensured; meanwhile, the stability of the filter paper shaft damping is ensured, so that the filter paper will not be broken due to the increase of the damping, or the filter paper will not fail to accurately monitor due to the decrease of the damping.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nuclear radiation measuring instruments, and particularly relates to a paper feeding method with constant linear velocity for a radioactive aerosol activity monitor. BACKGROUND

[0002] At present, the paper feeding devices in most radioactive aerosol activity monitors on the market have the following serious defects in use:

[0003] 1. Non-constant linear velocity: the existing paper feeding mechanism is driven by a constant-speed motor. As the filter paper is wound on the driving shaft, the effective radius of the filter paper continuously increases, resulting in an increase in the linear velocity of the filter paper. This not only affects the stability of the sampling flow, but also makes the residence time of the filter paper at the sampling port inconsistent, thereby introducing potential measurement errors.

[0004] 2. The change in the rotation speed of the filter paper will cause the damping of the paper feeding shaft to change. If the damping is too large, the filter paper will be broken; if the damping is too small, the photoelectric switch will fail to normally monitor the travel distance of the filter paper.

[0005] 3. Lack of adaptability: the existing solutions mostly rely on open-loop control or simple mechanical design, and cannot adapt to dynamic working conditions such as uneven filter paper thickness, eccentric winding drum, and changes in environmental temperature and humidity. High failure rate and frequent maintenance requirements seriously restrict the continuous operation capability and service life of the monitor. SUMMARY

[0006] The technical problem to be solved by the application is to provide a paper feeding method with constant linear velocity for a radioactive aerosol activity monitor, which controls the motor to rotate at a constant linear velocity through a PLC controller, so as to ensure that the filter paper always moves at a constant speed, guarantee the stability of the sampling flow in the gas path, and ensure the accuracy of the monitoring results. At the same time, the stability of the filter paper shaft damping is ensured, so that the filter paper will not be broken due to large damping, or the monitoring will not be inaccurate due to small damping.

[0007] To solve the above technical problems, the technical scheme adopted by the application is as follows: a paper feeding method with constant linear velocity for a radioactive aerosol activity monitor, which comprises the following steps: step one, filter paper installation: a new filter paper is arranged on the driven shaft in the paper feeding machine box, the starting section of the new filter paper is pulled out, and is sequentially overlapped on the grating transmission shaft and the transition shaft, and is adhered to the driving shaft;

[0008] Step two, filter paper feeding, the process is as follows:

[0009] Step 201, setting the rotation angular velocity of the motor and the instantaneous radius of the driving shaft , and synchronously saving them to the memory;

[0010] Step 202, the PLC controller controls the motor to rotate clockwise, the driving shaft rotates clockwise under the driving of the motor; the filter paper is wound on the driving shaft layer by layer at a constant linear speed under the driving of the motor;

[0011] Step three, paper detection: when the motor starts to work, the PLC controller controls the photoelectric switch to work, and the photoelectric switch detects the paper running situation of the filter paper. When the photoelectric switch detects that the filter paper on the driven shaft is left with 5%, the motor is turned off and the paper running is stopped.

[0012] Further, in step one, a paper running power assembly is arranged in the paper running machine box, the paper running power assembly comprises a motor arranged below the paper running machine box, the motor is arranged on one side of the paper running machine box, the driving shaft of the motor extends to the other side of the paper running machine box from the paper running machine box, and the driven shaft extends to the other side of the paper running machine box from the paper running machine box; the driving shaft and the driven shaft are arranged in parallel, and the radii of the driving shaft and the driven shaft are equal.

[0013] Further, the paper running machine box comprises a machine box frame and a machine box body arranged in the middle of the machine box frame, the machine box frame and the machine box body are integrally formed, the machine box body is a box structure with one side open, the open side of the machine box body is connected with the machine box frame, the motor is arranged on the inner side of the machine box body, and the driving shaft, the driven shaft, the grating transmission shaft and the transition shaft are arranged on the outer side of the machine box body.

[0014] Further, a photoelectric switch is further arranged in the paper running machine box, the photoelectric switch is installed on the grating transmission shaft; a communication interface is arranged at the bottom of the paper running machine box, the communication interface is connected with an external control box, a circuit board is arranged in the control box, the circuit board is integrated with a PLC controller, a memory, a PWM module and a timer connected with the PLC controller, and the signal output end of the photoelectric switch and the signal output end of the PWM module are connected with the signal input end of the PLC controller.

[0015] Further, the motor is a direct current brushless motor, and the motor is controlled by the PLC controller.

[0016] Further, in step 201, according to the rotational angular velocity of the motor and the instantaneous radius of the driving shaft , the paper running speed of the filter paper can be obtained, and the process is as follows:

[0017] Step 2011, the paper running speed of the filter paper is determined by the rotational angular velocity of the motor and the instantaneous radius of the driving shaft . ;

[0018] Step 2022, due to the paper feeding speed The length of the filter paper wound on the drive shaft is constant. The length of the filter paper increases linearly with time. The expression is ;in, The duration of the filter paper's movement;

[0019] Step 2023: As the duration of filter paper movement increases linearly, the cross-sectional area of ​​the filter paper wound on the drive shaft also increases. ;in, This refers to the cross-sectional area of ​​the filter paper wound on the drive shaft. The thickness of the filter paper wound on the drive shaft;

[0020] Step 2024, the radius of the drive shaft is The cross-sectional area of ​​the filter paper wound on the drive shaft is then... Combining the formula in step 2023, the instantaneous radius of the drive shaft is obtained. ;

[0021] Step 2025, combining steps 2021 and 2024, due to the paper feeding speed... If constant, then the angular velocity of the motor's rotation... .

[0022] Furthermore, in step 202, the filter paper needs to feed at a constant linear speed. Based on the instantaneous radius of the drive shaft and the rotational angular velocity of the motor in steps 2024 and 2025, the PLC controller adjusts the rotational angular velocity of the motor through the PWM module. Combined with the instantaneous radius of the filter paper winding around the drive shaft, the feed speed of the filter paper is kept constant.

[0023] The beneficial effect of this invention is that by controlling the motor to rotate at a constant linear speed through the PLC controller, the filter paper is kept moving at a constant speed, ensuring the stability of the sampling flow rate in the gas path and ensuring the accuracy of the monitoring results; at the same time, it ensures the stability of the filter paper shaft damping, ensuring that the filter paper will not break due to increased damping or fail to achieve accurate monitoring due to decreased damping.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the positional relationship between the paper feeder box and the filter paper in this invention.

[0026] Figure 2 This is a rear view of the paper feeder housing of the present invention.

[0027] Figure 3 This is a circuit block diagram of the present invention.

[0028] Figure 4 This is a flowchart of the method of the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1—Paper feeder housing; 2—Filter paper; 3—Motor;

[0031] 4—Driven shaft; 5—Driven shaft; 6—Photoelectric switch;

[0032] 7—Transition shaft; 8—Grate drive shaft; 9—Communication interface;

[0033] 10—PWM module; 11—Chassis frame; 12—Chassis body;

[0034] 13—Memory; 14—PLC controller; 15—Timer;

[0035] 16—Pressure device. Detailed Implementation

[0036] like Figures 1 to 4 The method shown is a paper feeding method with constant linear velocity in a radioactive aerosol activity monitor, which includes the following steps:

[0037] Step 1, Filter paper installation: Thread a new roll of filter paper 2 onto the driven shaft 4 inside the paper feeder housing 1, pull out the starting section of the new filter paper 2, overlap it onto the grating drive shaft 8 and the transition shaft 7 in sequence, and stick it onto the drive shaft 5.

[0038] Step 2: Feeding the filter paper, the process is as follows:

[0039] Step 201: Set the rotational angular velocity of motor 3. and the instantaneous radius of drive shaft 5 And simultaneously save it to memory 13;

[0040] Step 202: PLC controller 14 controls motor 3 to rotate clockwise, and drive shaft 5 rotates clockwise under the drive of motor 3; under the drive of motor 3, filter paper 2 is wound layer by layer on drive shaft 5 at a constant linear speed.

[0041] Step 3, Paper Feed Detection: When motor 3 starts working, PLC controller 14 controls photoelectric switch 6 to work. Photoelectric switch 6 detects the paper feed of filter paper 2. When photoelectric switch 6 detects that 5% of filter paper 2 remains on driven shaft 4, motor 3 is turned off and paper feed is stopped.

[0042] This invention controls the motor 3 to rotate at a constant linear speed by controlling the PLC controller 14, ensuring that the filter paper 2 always maintains a constant speed, thus ensuring the stability of the sampling flow rate in the gas path and the accuracy of the monitoring results; at the same time, it ensures the stability of the filter paper shaft damping, ensuring that the filter paper will not break due to increased damping, or that inaccurate monitoring will not occur due to decreased damping.

[0043] like Figure 1 As shown, in step one, to ensure greater stability of the filter paper 2 during paper feeding, the clamping device 16 presses down the filter paper 2, increasing the damping between the filter paper 2 and the grating drive shaft 8. In step three, an alarm can be integrated onto the circuit board and connected to the PLC controller 14. When the photoelectric switch 6 detects that 5% of the filter paper 2 remains on the driven shaft 4, the alarm sounds a paper replacement prompt, and simultaneously displays a filter paper replacement prompt on the display screen connected to the PLC controller 14. Furthermore, during the entire paper feeding process, paper feeding can be paused or resumed as needed.

[0044] It should be noted that all parameters during operation are transmitted to the PLC controller 14. Frequency modulation can be achieved by changing the number of pulses per unit time through the PWM module; voltage modulation can be achieved by changing the duty cycle. The larger the duty cycle, the larger the average voltage and the larger the amplitude; the smaller the duty cycle, the smaller the average voltage and the smaller the amplitude. This controls the motor speed, ultimately achieving constant paper feed speed.

[0045] In this embodiment, in step one, a paper feeding power assembly is provided inside the paper feeding machine housing 1. The paper feeding power assembly includes a motor 3 located below the paper feeding machine housing 1. The motor 3 is arranged on one side of the paper feeding machine housing 1. The drive shaft 5 of the motor 3 passes through the paper feeding machine housing 1 and extends to the other side of the paper feeding machine housing 1. The driven shaft 4 passes through the paper feeding machine housing 1 and extends to the other side of the paper feeding machine housing 1. The drive shaft 5 and the driven shaft 4 are arranged in parallel, and the radii of the drive shaft 5 and the driven shaft 4 are equal.

[0046] In this embodiment, the paper feeding machine chassis 1 includes a chassis frame 11 and a chassis body 12 disposed in the middle of the chassis frame 11. The chassis frame 11 and the chassis body 12 are integrally formed. The chassis body 12 is a box structure with a side opening. The side opening of the chassis body 12 is connected to the chassis frame 11. The motor 3 is arranged inside the chassis body 12. The drive shaft 5, the driven shaft 4, the grating drive shaft 8, and the transition shaft 7 are all arranged outside the chassis body 12.

[0047] In this embodiment, a photoelectric switch 6 is also provided inside the paper feeder chassis 1, and the photoelectric switch 6 is mounted on the grating drive shaft 8; a communication interface 9 is provided at the bottom of the paper feeder chassis 1, and the communication interface 9 is connected to an external control box. A circuit board is provided inside the control box, and the circuit board integrates a PLC controller 14 and a memory 13, a PWM module 10, and a timer 15 connected to the PLC controller 14. The signal output terminals of the photoelectric switch 6 and the PWM module 10 are both connected to the signal input terminals of the PLC controller 14.

[0048] In this embodiment, the motor 3 is a DC brushless motor, and the motor 3 is controlled by the PLC controller 14.

[0049] In actual use, the drive shaft 5 is driven by a variable-speed DC brushless motor with an encoder, used to wind the filter paper 2. The speed of the motor 3 is precisely controlled by the PLC controller 14 through a PWM signal, and dynamically adjusted according to the instantaneous radius of the drive shaft 5 calculated in real time, ensuring that the linear velocity of the filter paper 2 remains constant, thereby guaranteeing the stability of the sampling flow rate and the accuracy of the measurement results.

[0050] In this embodiment, in step 201, based on the rotational angular velocity of motor 3... and the instantaneous radius of drive shaft 5 The paper feed speed of filter paper 2 can be obtained through the following process:

[0051] Step 2011, Paper feed speed of filter paper 2 The rotational angular velocity of motor 3 The instantaneous radius of the drive shaft 5 determines ,Right now;

[0052] Step 2022, due to the paper feeding speed of filter paper 2 The length of the filter paper wound on the drive shaft 5 is constant. The length of the filter paper increases linearly with time. The expression is ;in, The duration of the movement of filter paper 2 is denoted as 15. In actual use, the duration of the movement of filter paper 2 is obtained through timer 15, and the data can be displayed in real time on the display screen connected to PLC controller 14.

[0053] Step 2023: As the duration of the filter paper 2's movement increases linearly, the cross-sectional area of ​​the filter paper 2 wound on the drive shaft 5 also increases accordingly. ;in, The cross-sectional area of ​​the filter paper 2 wound on the drive shaft 5 is... The thickness of the filter paper 2 wound on the drive shaft 5;

[0054] Step 2024, the radius of the drive shaft 5 is The cross-sectional area of ​​the filter paper 2 wound on the drive shaft 5 is then... Combining the formula in step 2023, the instantaneous radius of the drive shaft 5 is obtained. ;

[0055] Step 2025, combining steps 2021 and 2024, due to the paper feeding speed of filter paper 2 If the rotational angular velocity of motor 3 is constant, then... .

[0056] In this embodiment, in step 202, the filter paper 2 needs to feed at a constant linear speed. Based on the instantaneous radius of the drive shaft 5 and the rotational angular velocity of the motor 3 in steps 2024 and 2025, the PLC controller 14 adjusts the rotational angular velocity of the motor 3 through the PWM module 10. Combined with the instantaneous radius of the filter paper 2 wrapped around the drive shaft 5, the feeding speed of the filter paper 2 is kept constant.

[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A paper-feeding method for a radioaerosol activity monitor in which the linear velocity is constant, characterized in that, The method comprises the following steps: Step one, filter paper installation: a new filter paper (2) is arranged on the driven shaft (4) in the paper machine box (1), the starting section of the new filter paper (2) is pulled out, and is sequentially overlapped on the grating transmission shaft (8) and the transition shaft (7), and is adhered on the driving shaft (5); Step two, filter paper papering, the process is as follows: Step 201, set the rotation angular velocity of the motor (3) and the instantaneous radius of the main shaft (5) and synchronously save into the memory (13) Step 202, the PLC controller (14) controls the motor (3) to rotate clockwise, the driving shaft (5) rotates clockwise under the driving of the motor (3); the filter paper (2) is wound on the driving shaft (5) layer by layer at a constant linear speed under the driving of the motor (3); Step three, papering detection: when the motor (3) starts to work, the PLC controller (14) controls the photoelectric switch (6) to work, the photoelectric switch (6) detects the papering condition of the filter paper (2), and when the photoelectric switch (6) detects that the filter paper (2) on the driven shaft (4) is left for 5%, the motor (3) is turned off and the papering is stopped; In step one, the papering power assembly is arranged in the papering machine box (1), the papering power assembly comprises a motor (3) arranged below the papering machine box (1), the motor (3) is arranged on one side of the papering machine box (1), the driving shaft (5) of the motor (3) penetrates through the papering machine box (1) and extends to the other side of the papering machine box (1), and the driven shaft (4) penetrates through the papering machine box (1) and extends to the other side of the papering machine box (1); the driving shaft (5) and the driven shaft (4) are arranged in parallel, and the radii of the driving shaft (5) and the driven shaft (4) are equal; The papering machine box (1) comprises a machine box frame (11) and a machine box body (12) arranged in the middle of the machine box frame (11), the machine box frame (11) and the machine box body (12) are integrally formed, the machine box body (12) is a box structure with one side open, the open side of the machine box body (12) is connected with the machine box frame (11), the motor (3) is arranged on the inner side of the machine box body (12), and the driving shaft (5), the driven shaft (4), the grating transmission shaft (8) and the transition shaft (7) are arranged on the outer side of the machine box body (12); The papering machine box (1) is further provided with a photoelectric switch (6), the photoelectric switch (6) is installed on the grating transmission shaft (8); a communication interface (9) is arranged at the bottom of the papering machine box (1), the communication interface (9) is connected with an external control box, a circuit board is arranged in the control box, a PLC controller (14), a memory (13), a PWM module (10) and a timer (15) are integrated on the circuit board, and the signal output ends of the photoelectric switch (6) and the PWM module (10) are connected with the signal input end of the PLC controller (14); In step 201, the rotational angular velocity of the motor (3) and the instantaneous radius of the driving shaft (5) are used to obtain the paper travel speed of the filter paper (2) as follows: Step 2011, paper speed of filter paper (2) from the rotational angular velocity of the motor (3) and the instantaneous radius of the drive shaft (5) determines, i.e. ; Step 2022, the paper speed of the filter paper (2) constant, so the length of the filter paper wound on the driving shaft (5) increases linearly over time, and the length of the filter paper wound on the driving shaft (5) is expressed as ; wherein is the movement time of the filter paper (2); Step 2023, with the linear increase of the movement time of the filter paper (2), the cross-sectional area of the filter paper (2) wound on the driving shaft (5) also increases, then ; wherein, is the cross-sectional area of the filter paper (2) wound on the driving shaft (5), is the thickness of the filter paper (2) wound on the driving shaft (5); Step 2024, the radius of the driving shaft (5) is , then the cross-sectional area of the filter paper (2) wound on the driving shaft (5) is ; combined with the formula in step 2023, the instantaneous radius of the driving shaft (5) is ; Step 2025, in combination with step 2021 and step 2024, the walking speed of the filter paper (2) is constant, then the rotational angular velocity of the motor (3) ; In step 202, the filter paper (2) needs to be fed at a constant linear speed. According to the instantaneous radius of the driving shaft (5) and the angular velocity of the motor (3) in steps 2024 and 2025, the PLC controller (14) adjusts the angular velocity of the motor (3) through the PWM module (10), and combines the instantaneous radius of the filter paper (2) wound on the driving shaft (5) to make the feeding speed of the filter paper (2) constant.

2. The paper speed constant method of claim 1, wherein: The motor (3) is a direct-current brushless motor, and the motor (3) is controlled by the PLC controller (14).

Images