A device and method for automatically measuring the change of suspension liquid level

Abstract

The present invention discloses an automatic measuring device and method for the change of liquid level of a suspension. A servo motor of the device is fixedly installed, one end of a screw rod is fixedly connected to an output shaft of the servo motor, the screw rod passes through a slider and is suspended in the air, a bracket is in an L-shaped structure, one end of a horizontal section of the bracket is fixedly connected to the slider, and the other end is connected to one end of a vertical section, and the other end of the vertical section is used for fixedly installing a photoelectric sensor; the slider moves up and down with the bracket through forward and reverse rotation of the screw rod, so that the photoelectric sensor moves up and down; the photoelectric sensor emits a light signal to illuminate the surface of a drug slurry to be detected, detects the intensity of the reflected light, and transmits it back to a PLC controller; before and after the PLC controller changes the height of the drug slurry, the photoelectric sensor detects the intensity of the reflected light, adjusts the height of the slider, and calculates that when the reflected light intensity is the same again, the distance the photoelectric sensor moves up or down is the change height of the drug slurry level.

Description

Technical Field

[0001] The invention relates to an automatic and accurate measurement device and method for the change of suspension liquid level, which is suitable for the scene where the liquid level of a suspension with weak light penetration and strong reflectivity changes gradually, and is particularly suitable for the change of the liquid level of a slurry-like pyrotechnic agent with strong light reflection, and belongs to the field of pyrotechnic device assembly. Background Art

[0002] The electric ignition head is a typical aerospace pyrotechnic product, which is widely used in the aerospace field. During the assembly process of the electric ignition head, the pyrotechnic agent is made into a suspension. As the product is produced, the agent is gradually taken away, the amount of agent in the container gradually decreases, and the liquid level gradually decreases. In order to ensure that the amount of agent taken away by each product is consistent, the depth of the product immersed in the slurry must be consistent. Therefore, it is necessary to accurately monitor the changes in the slurry level in real time and adjust the depth of the product immersed in the slurry in real time. With the development of the aerospace industry, the demand for pyrotechnics such as electric ignition heads has increased, and production efficiency is required to be rapidly improved. At present, in the production of pyrotechnics such as electric ignition heads, the changes in the liquid level are observed by human eyes, and the depth of the product immersed in the slurry is manually adjusted. The current method has the following problems:

[0003] (1) Manual observation of liquid level changes, poor accuracy

[0004] At present, domestic electric ignition head products are completely dependent on manual operation. The changes in liquid level are mainly observed by the naked eye, and the depth of product immersion in the agent is manually adjusted. The change in the height of the slurry liquid level cannot be accurately measured, and the depth of product immersion in the slurry also depends entirely on manual experience, which cannot be quantified and cannot be quickly and accurately controlled, resulting in poor control of product qualification rate.

[0005] (2) The drug is sensitive and high-power detection devices cannot be used

[0006] Since explosives are extremely sensitive, high-power detection devices with high liquid level detection accuracy cannot be used. At the same time, in order to ensure the safety of the production process, the explosives are placed in small metal cans, and large-volume detection tools are not suitable for ignition head explosives liquid level detection. Summary of the invention

[0007] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide an automatic and accurate measurement device and method for the change in the liquid level of a suspension, to solve the problems of slow changes in the liquid level of the slurry and the difficulty in measuring the change in the production process of pyrotechnics such as electric ignition heads, the dangerous and narrow measurement environment, and the difficulty in detecting trace changes in the liquid level of the slurry in flammable and explosive environments and narrow spaces, to improve mass production efficiency and improve product quality consistency.

[0008] The solution to the technical problem of the present invention is: an automatic and accurate measuring device for the change of the liquid level of a suspension, the device comprising a photoelectric sensor, a bracket, a screw rod, a slider, a servo motor, and a PLC controller;

[0009] The servo motor is fixedly installed. After installation, the output shaft of the servo motor is perpendicular to the ground. One end of the screw rod is fixedly connected to the output shaft of the servo motor, so that the screw rod is perpendicular to the ground. The screw rod passes through the slider and is suspended in the air. The bracket is L-shaped and consists of a vertical section and a horizontal section. The vertical section and the horizontal section are perpendicular to each other. One end of the horizontal section of the bracket is fixedly connected to the slider, and the other end is connected to one end of the vertical section. The other end of the vertical section is used to fix the photoelectric sensor; through the forward and reverse rotation of the screw rod, the slider moves up and down along the screw rod, and the slider moves up and down with the bracket to realize the up and down movement of the photoelectric sensor; the servo motor is connected to the PLC controller, and the PLC controller records the forward and reverse rotation and number of revolutions of the servo motor; the photoelectric sensor emits The light signal is irradiated on the surface of the detected slurry, and the intensity of the reflected light is detected and transmitted back to the PLC controller; the PLC controller records the initial light signal threshold of the light intensity transmitted back when the detected slurry surface is at the initial position, and when the slurry surface changes to the detection height, the reflected light intensity is compared to determine whether the slurry surface height has changed. If it has changed, the servo motor is controlled to rotate forward or reverse, driving the screw to rotate, and the slider drives the photoelectric sensor to approach or move away from the slurry surface through the bracket until the photoelectric sensor detects that the reflected light intensity is equal to the initial light signal threshold again. The distance the photoelectric sensor moves up or down is calculated according to the screw pitch, screw rotation direction, and number of rotations, which is the change in the slurry surface height.

[0010] The change in the height of the slurry surface is: Δh=h2-h1, h2=L×N2, h1=L×N1, L is the screw pitch, N1 is the number of servo motor rotations corresponding to the photoelectric sensor being at the reference height of the slurry surface, and N2 is the number of servo motor rotations corresponding to the photoelectric sensor stopping moving after step S4 is executed.

[0011] Preferably, the photoelectric sensor, screw rod, servo motor and PLC controller are all general tool equipment.

[0012] Preferably, the vertical section of the support is in the shape of a hollow tube, and the end of the photoelectric sensor is fixed in the hollow tube of the end of the support by means of threads.

[0013] Another technical solution of the present invention is: a method for automatically and accurately measuring the change in the liquid level of a suspension, the method comprising the following steps:

[0014] S1. Before working, set the light signal detection threshold; the specific method is: when the photoelectric sensor is located at any reference height h0 directly above the slurry surface, test the reflected light signal intensity and send the reflected light signal intensity to the PLC controller;

[0015] S2, the PLC controller sets the light signal intensity f_h0 of the photoelectric sensor at a height h0 from the slurry surface as the feedback light signal threshold, and records the number of revolutions of the servo motor corresponding to the photoelectric sensor at a reference height from the slurry surface;

[0016] S3, controlling the photoelectric sensor to move vertically downward from a reference height position away from the surface of the slurry, the photoelectric sensor emits a light signal, and simultaneously receives a feedback light signal, and feeds back the feedback light signal intensity to the PLC controller;

[0017] S4, during the movement of the photoelectric sensor, the photoelectric sensor will transmit the light feedback signal strength, and the servo motor will transmit the number of rotations to the PLC controller in real time;

[0018] S5, the PLC controller judges the feedback light signal strength. When the feedback light signal strength is lower than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move downward. When the light feedback signal strength is higher than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move upward. When the light feedback signal strength reaches the feedback light signal threshold f_h0, the photoelectric sensor is controlled to stop moving.

[0019] S6. PLC calculates the change in the height of the slurry surface according to the number of revolutions of the servo motor at this time, the number of revolutions of the servo motor corresponding to the height h0 of the photoelectric sensor from the slurry surface, and the lead screw pitch.

[0020] Preferably, in step S5, the change in the height of the slurry liquid surface is: Δh=h2-h1, h2=L×N2, h1=L×N1, L is the screw pitch, N1 is the number of rotations of the servo motor corresponding to the photoelectric sensor being at a reference height from the slurry liquid surface, and N2 is the number of rotations of the servo motor corresponding to the photoelectric sensor stopping moving after step S4 is executed.

[0021] The beneficial effects of the present invention compared with the prior art are:

[0022] (1) The automatic measuring device for the change of the liquid level of the suspension provided by the present invention uses the light intensity reflected by the light emitted by the photoelectric sensor to reflect the liquid level distance. The emitted light is visible light with extremely small light energy, which will not cause harm to sensitive explosives and is safe to use.

[0023] (2) The measuring device of the present invention is small in size. Only the vertical section of the bracket is above the medicine surface. The rest of the parts (including the horizontal section of the bracket, servo motor, screw and PLC controller) are not above the medicine, which does not affect the normal production of the product. The diameter of the bracket can be selected according to the actual use environment. The horizontal section of the bracket can be made very long, away from the narrow environment where the medicine is used, which is convenient for the production of pyrotechnics.

[0024] (3) The present invention has high measurement accuracy. Through the screw motor combination, it can achieve measurement of liquid level with an accuracy of 0.1 mm.

[0025] (4) The present invention detects the liquid level in real time through the device, and can accurately obtain the height data of the liquid level in real time without human intervention, thereby providing a basis for realizing rapid and automated product production.

[0026] (5) The automatic and accurate measurement of the liquid level of the slurry of the present invention provides data support for the precise control of the immersion depth of subsequent products, which is beneficial to improving the consistency of product production quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the assembly of the automatic measuring device for the liquid level change of the suspension according to the embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of the process of the method for automatically measuring the change in the liquid level of a suspension according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the present invention provides a device for automatically and accurately measuring the change of the liquid level of a suspension, the device comprising a photoelectric sensor, a bracket, a screw rod, a slider, a servo motor, and a PLC controller;

[0031] The servo motor is fixedly installed. After installation, the output shaft of the servo motor is perpendicular to the ground. One end of the screw rod is fixedly connected to the output shaft of the servo motor, so that the screw rod is perpendicular to the ground. The screw rod passes through the slider and is suspended in the air. The bracket is L-shaped and consists of a vertical section and a horizontal section. The vertical section and the horizontal section are perpendicular to each other. One end of the horizontal section of the bracket is fixedly connected to the slider, and the other end is connected to one end of the vertical section. The other end of the vertical section is used to fix the photoelectric sensor; through the forward and reverse rotation of the screw rod, the slider moves up and down along the screw rod, and the slider moves up and down with the bracket to realize the up and down movement of the photoelectric sensor; the servo motor is connected to the PLC controller, and the PLC controller records the forward and reverse rotation and number of revolutions of the servo motor; the photoelectric sensor emits The light signal is irradiated on the surface of the detected slurry, and the intensity of the reflected light is detected and transmitted back to the PLC controller; the PLC controller records the initial light signal threshold of the light intensity transmitted back when the detected slurry surface is at the initial position, and when the slurry surface changes to the detection height, the reflected light intensity is compared to determine whether the slurry surface height has changed. If it has changed, the servo motor is controlled to rotate forward or reverse, driving the screw to rotate, and the slider drives the photoelectric sensor to approach or move away from the slurry surface through the bracket until the photoelectric sensor detects that the reflected light intensity is equal to the initial light signal threshold again. The distance the photoelectric sensor moves up or down is calculated according to the screw pitch, screw rotation direction, and number of rotations, which is the change in the slurry surface height.

[0032] The change in the height of the slurry liquid level is: Δh=h2-h1, h2=L×N2, h1=L×N1, L is the screw pitch, N1 is the number of rotations of the servo motor corresponding to the photoelectric sensor being at the reference height of the slurry liquid level, and N2 is the number of rotations of the servo motor corresponding to the photoelectric sensor stopping moving after step S4 is executed.

[0033] Preferably, the electric sensor, screw rod, servo motor and PLC controller are all general tool equipment.

[0034] Preferably, the vertical section of the support is in the shape of a hollow tube, and the end of the photoelectric sensor is fixed in the hollow tube of the end of the support by means of threads.

[0035] like Figure 2 As shown, another technical solution provided by the present invention is: a method for automatically and accurately measuring the change in the liquid level of a suspension, the method comprising the following steps:

[0036] S1. Before working, set the light signal detection threshold; the specific method is: when the photoelectric sensor is located at any reference height h0 directly above the slurry surface, test the reflected light signal intensity and send the reflected light signal intensity to the PLC controller;

[0037] S2, the PLC controller sets the optical signal intensity f_h0 at the height h0 from the sensor to the slurry surface as the feedback optical signal threshold, and records the number of servo motor rotations corresponding to the photoelectric sensor at the reference height from the slurry surface;

[0038] S2, control the photoelectric sensor to move vertically downward from a reference height position away from the surface of the slurry, the photoelectric sensor emits a light signal, and simultaneously receives a feedback light signal, and feeds back the feedback light signal intensity to the PLC controller;

[0039] S3, during the movement of the sensor, the sensor will transmit the light feedback signal strength, and the servo motor will transmit the number of rotations to the PLC controller in real time;

[0040] S4, the PLC controller judges the feedback light signal strength. When the feedback light signal strength is lower than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move downward. When the light feedback signal strength is higher than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move upward. When the light feedback signal strength reaches the feedback light signal threshold f_h0, the photoelectric sensor is controlled to stop moving.

[0041] S5. PLC calculates the change in the height of the slurry surface according to the number of revolutions of the servo motor at this time, the number of revolutions of the servo motor corresponding to the height h0 of the photoelectric sensor from the slurry surface, and the lead screw pitch.

[0042] The change in the height of the slurry surface is: Δh=h2-h1, h2=L×N2, h1=L×N1, L is the screw pitch, N1 is the number of servo motor rotations corresponding to the photoelectric sensor being at the reference height of the slurry surface, and N2 is the number of servo motor rotations corresponding to the photoelectric sensor stopping moving after step S4 is executed.

[0043] Example 1: A device for automatically and accurately measuring the change in the liquid level of a suspension

[0044] In this embodiment, an automatic and accurate measurement device for the change of the liquid level of a suspension is composed of a photoelectric sensor, an L-shaped bracket, a screw rod, a slider, a servo motor, a PLC controller and a connecting line. Among them, the electric sensor, the screw rod, the servo motor and the PLC controller are all general tools and equipment. The bracket can be large or small according to the use environment and is only used to support the sensor. See the attached Figure 1 .

[0045] The bracket is an L-shaped structure with a hollow tube shape. The photoelectric sensor is installed in the hollow tube of the bracket. The end of the photoelectric sensor is fixed to the end of the bracket through threads. The photoelectric sensor line is directly connected to the PLC controller.

[0046] The lead screw is connected to a small servo motor as a whole. When the servo motor rotates, it drives the lead screw to rotate. The motor is fixed on a wall or other fixed object, and the lead screw is vertically downward. The servo motor is connected to a PLC controller, and the forward and reverse rotation and number of rotations of the servo motor are all controlled by the PLC.

[0047] The bracket is connected to the lead screw through a slider, the bracket is fixed on the slider, and the slider is mounted on the lead screw. Through the forward and reverse rotation of the lead screw, the slider moves up and down along the lead screw, and the slider moves the bracket up and down, realizing the up and down movement of the photoelectric sensor.

[0048] The photoelectric sensor emits a beam of light from a fixed initial position. After the light hits the liquid surface, it is reflected back to the photoelectric sensor. The photoelectric sensor detects that the intensity of the reflected light is a certain value, which is set as the initial light signal threshold. As the liquid level changes, the light intensity detected by the photoelectric sensor will change. The bracket drives the photoelectric sensor closer to or away from the liquid surface until the light intensity is detected again to be equal to the light signal threshold. The distance the photoelectric sensor moves up or down is the height of the liquid level change.

[0049] The distance the photoelectric sensor moves, that is, the distance the bracket slides with the screw, can be calculated through the screw specifications and the number of rotations of the servo motor. The PLC controller is used to calculate this value in real time to achieve automatic and accurate measurement of the liquid level change.

[0050] Embodiment 2:

[0051] A method for automatically and accurately measuring the change in the liquid level of a suspension, comprising the following steps:

[0052] (1) Install a set of photoelectric sensors above the liquid level to be measured. The photoelectric sensors are fixed on a set of vertically installed screw rods through a bracket. One end of the screw rod is connected to a servo motor. When working, the motor drives the screw rod to rotate, and the bracket moves up and down along the screw rod, thereby realizing the vertical up and down movement of the photoelectric sensor above the liquid level (see attached). Figure 1 ).

[0053] (2) The servo motor and the photoelectric sensor are connected to the same PLC controller. The photoelectric sensor sends and receives light signals. The PLC controller controls the direction and number of rotations of the motor based on the strength of the light signal fed back by the photoelectric sensor in real time.

[0054] (3) Before work, the light signal detection threshold is set according to the different types of suspensions. The method is as follows: the photoelectric sensor is located at a height h0 just above the liquid surface, the intensity of the reflected light signal is tested, and the light signal intensity f_h0 at a height h0 from the photoelectric sensor to the liquid surface is set as the feedback light signal threshold.

[0055] (4) When working, the photoelectric sensors all move vertically downward from the same reference height position away from the liquid surface. The photoelectric sensors send out light signals and receive feedback light signals at the same time. When the intensity of the feedback light signal is lower than the threshold value f_h0, the photoelectric sensor continues to move downward. When the intensity of the light feedback signal is higher than the threshold value f_h0, the photoelectric sensor continues to move upward. When the intensity of the light feedback signal reaches the threshold value f_h0, the photoelectric sensor stops moving.

[0056] (5) During the movement of the photoelectric sensor, the photoelectric sensor transmits data such as the intensity of the light feedback signal and the number of revolutions of the servo motor to the PLC in real time. The PLC calculates the change in the liquid level based on the received data. See attached Figure 2 .

[0057] (6) When measuring the liquid level data for the first time, when the light signal feedback intensity reaches the threshold, the photoelectric sensor stops moving downward, and the motor drives the screw to rotate N1 circles. After a period of time, the liquid level data is measured for the second time. When the light signal feedback intensity reaches the threshold again, the photoelectric sensor stops moving downward, and the motor drives the screw to rotate N2 circles.

[0058] (7) PLC calculates the change in the liquid level of the slurry based on the received data, the change Δh=h2-h1, h2=screw pitch*number of rotations=L*N2, h1=screw pitch*number of rotations=L*N1, L is the screw pitch, also called the screw lead, that is, Δh=h2-h1=L*(N2-N1); for example: the screw lead L is 1.0mm, the number of screw rotations N1 is 15 in the first measurement, and the number of screw rotations N2 is 15.2 in the second measurement, then the change in the liquid level is Δh=L*(N2-N1)=1.0*(15.2-15.0)=0.2mm.

[0059] (8) Through the combination of photoelectric sensors and screw rods, accurate measurement of liquid level changes can be achieved, with a detection accuracy of up to 0.1 mm. The entire detection process is fully automatic, and the liquid level height data can be transmitted to the next level of equipment through PLC, thereby achieving continuous, automatic and accurate production.

[0060] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for measuring the liquid level change of a suspension using an automatic and accurate measuring device, characterized in that ,The measuring device includes a photoelectric sensor, a bracket, a lead rod, a slider, a servo motor, and a PLC controller; The servo motor is fixedly installed. After installation, the output shaft of the servo motor is perpendicular to the ground. One end of the screw rod is fixedly connected to the output shaft of the servo motor, so that the screw rod is perpendicular to the ground. The screw rod passes through the slider and is suspended in the air. The bracket is L-shaped and consists of a vertical section and a horizontal section. The vertical section and the horizontal section are perpendicular to each other. One end of the horizontal section of the bracket is fixedly connected to the slider, and the other end is connected to one end of the vertical section. The other end of the vertical section is used to fix the photoelectric sensor; through the forward and reverse rotation of the screw rod, the slider moves up and down along the screw rod, and the slider moves up and down with the bracket to realize the up and down movement of the photoelectric sensor; the servo motor is connected to the PLC controller, and the PLC controller records the forward and reverse rotation and number of revolutions of the servo motor; the photoelectric sensor emits The light signal is irradiated on the surface of the detected slurry, and the intensity of the reflected light is detected and transmitted back to the PLC controller; the PLC controller records the initial light signal threshold of the light intensity transmitted back when the detected slurry surface is at the initial position, and when the slurry surface changes to the detection height, the reflected light intensity is compared to determine whether the slurry surface height has changed. If it has changed, the servo motor is controlled to rotate forward or reverse, and the lead screw is driven to rotate. The slider drives the photoelectric sensor to approach or move away from the slurry surface through the bracket until the photoelectric sensor detects that the reflected light intensity is equal to the initial light signal threshold again. According to the lead screw pitch, the direction of lead screw rotation, and the number of rotations, the distance the photoelectric sensor moves up or down is calculated, which is the change in the slurry surface height; The method comprises the following steps: S1. Setting the light signal detection threshold; the specific method is: when the photoelectric sensor is located at any reference height h0 directly above the slurry surface, testing the reflected light signal intensity, and sending the reflected light signal intensity to the PLC controller; S2, the PLC controller sets the light signal intensity f_h0 of the photoelectric sensor at a height h0 from the slurry surface as the feedback light signal threshold, and records the number of revolutions of the servo motor corresponding to the photoelectric sensor at a reference height from the slurry surface; S3, controlling the photoelectric sensor to move vertically downward from a reference height position away from the surface of the slurry, the photoelectric sensor emits a light signal, and simultaneously receives a feedback light signal, and feeds back the feedback light signal intensity to the PLC controller; S4, during the movement of the photoelectric sensor, the photoelectric sensor will transmit the light feedback signal strength, and the servo motor will transmit the number of rotations to the PLC controller in real time; S5, the PLC controller judges the feedback light signal strength. When the feedback light signal strength is lower than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move downward. When the light feedback signal strength is higher than the feedback light signal threshold f_h0, the photoelectric sensor is controlled to continue to move upward. When the light feedback signal strength reaches the feedback light signal threshold f_h0, the photoelectric sensor is controlled to stop moving. S6, PLC calculates the change in the height of the slurry liquid surface according to the number of revolutions of the servo motor at this time, the number of revolutions of the servo motor corresponding to the height h0 of the photoelectric sensor from the slurry liquid surface, and the lead screw pitch; The change in the height of the slurry liquid surface is: Δh=h2-h1, h2=L×N2, h1=L×N1, L is the screw pitch, N1 is the number of servo motor rotations corresponding to the photoelectric sensor being at the reference height of the slurry liquid surface, and N2 is the number of servo motor rotations corresponding to the photoelectric sensor stopping moving after step S4 is executed.

2. A method for measuring the liquid level change of a suspension using an automatic and accurate measuring device according to claim 1, characterized in that The photoelectric sensor, lead screw, servo motor and PLC controller are all general tool equipment.

3. A method for measuring the liquid level change of a suspension using an automatic and accurate measuring device according to claim 1, characterized in that The vertical section of the bracket is in the shape of a hollow tube, and the end of the photoelectric sensor is fixed in the hollow tube of the end of the bracket through threads.

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