Volume tube standard volume value calibration method based on response time of electromagnetic directional valve

Abstract

The invention discloses a volume tube standard volume value calibration method based on response time of an electromagnetic directional valve. A high-speed camera starting signal is triggered when the volume tube baffle triggers the approach detection switch, and the high-speed camera is started to shoot to obtain a dithering image when the electromagnetic reversing valve is opened. Then, the gray response value of the shaking image of the electromagnetic reversing valve is extracted, the gray response value is drawn into a graph along with the change of time, the graph is analyzed, and the frame number corresponding to the first wave crest of the graph is the opening duration of the electromagnetic reversing valve. Similarly, the closing duration of the electromagnetic reversing valve is obtained, the difference between the two durations is obtained to obtain the response time difference, the response time difference is substituted into the volume loss formula to be calculated, and the standard volume value loss volume when the volume pipe standard volume value is calibrated is obtained. According to the invention, a high-speed camera technology is introduced as an observation means, and the real opening time and closing time of the electromagnetic reversing valve can be measured actively, objectively and directly by accurately capturing and analyzing the high-speed images.

Description

Technical Field

[0001] The invention belongs to the technical field of verification and calibration of liquid flow metering equipment, and relates to a method for calibrating a standard volume value of a volume tube based on the response time of an electromagnetic reversing valve. Background Art

[0002] A normally closed pilot-operated solenoid directional valve is used as the commutator in the calibration test of the standard volume value of a piston-type volumetric tube flow standard device. This solenoid directional valve operates based on electromagnetic mechanics and fluid mechanics and primarily consists of a solenoid coil, valve core, valve seat, pilot orifice, spring, and housing.

[0003] In the normally closed electromagnetic reversing valve of the prior art, when the external control circuit applies voltage to the electromagnetic coil, the coil generates a magnetic field that attracts the valve core to move, causing it to gradually separate from the valve seat. During this process, the pilot hole is exposed first, allowing fluid to flow and form a pressure difference. This pilot action further promotes the movement of the valve core. As the valve core continues to move, the pilot hole is fully opened, and pressure is established on the other side of the main valve core, driving the valve core to quickly complete the opening stroke and achieve free flow of fluid. When the control circuit is powered off, the electromagnetic coil loses its magnetism, and the valve core resets under the action of the spring force, re-fitting tightly with the valve seat, cutting off the fluid channel, and the valve returns to the normally closed state. When the valve core displacement reaches the highest point, it indicates that the electromagnetic reversing valve is open, and when the valve core displacement reaches the lowest point, it indicates that the electromagnetic reversing valve is closed. The period from the electromagnetic reversing valve being powered on to opening or from the electromagnetic reversing valve being powered off to closing is called the response time. When the calibration flow of the piston-type volume tube increases and the fluid pressure increases, the time required for the electromagnetic reversing valve to open becomes longer and the time required to close becomes shorter, which causes the time difference Δt between the two to change, and thus causes the calibration result of the standard volume value of the volume tube to change.

[0004] Traditionally, solenoid directional valves, which control the flow of fluid, typically assume the same opening and closing response times—that is, a fixed, symmetrical "opening and closing time difference." This assumption simplifies system design and control logic. In volumetric calibration of standard volume tubes, a specific operating procedure is often employed: the calibration process primarily uses a low flow rate, with the piston moving rapidly for the first half of its stroke. As the piston nears the end of its stroke, the operation switches to another fluid path, completing the remaining stroke at a very slow rate. The core purpose of this "fast-slow" stroke switching method is to ensure that the solenoid directional valve's switching action occurs during the slow piston movement phase, thereby minimizing the impact of any timing errors on the final volume measurement. This design essentially "passively mitigates" the time difference through operating condition optimization, rather than proactively addressing the core issue of difficult response time measurement.

[0005] Therefore, it is necessary to find a method that can conveniently and accurately obtain the influence of the response time of the electromagnetic reversing valve on the standard volume value of the volume tube. Summary of the Invention

[0006] The present invention aims to analyze the problem that the opening and closing time difference of the electromagnetic reversing valve cannot be measured, resulting in a large error in the calibration of the standard volume value of the volume tube, and provide a simple-to-operate and accurate method for measuring the response time of the electromagnetic reversing valve for measuring the lost volume during the calibration of the standard volume value of the volume tube.

[0007] The present invention comprises the following steps:

[0008] Connect the non-contact measuring device to the control system signal, install the electromagnetic reversing valve on the measuring platform, and start the calibration process of the standard volume value of the volume tube;

[0009] During the calibration process of the standard volume value of the volume tube, when the volume tube triggers the signal device, the non-contact measuring device is started to obtain a dynamic characteristic image of the moment the electromagnetic reversing valve is opened, and the medium flows into the first measuring container at this time; when the volume tube triggers the signal device again, the non-contact measuring device is started again to obtain a dynamic characteristic image of the moment the electromagnetic reversing valve is closed, and the medium flows into the second measuring container at this time;

[0010] Extracting characteristic response values ​​of the dynamic characteristic image of the electromagnetic reversing valve through a data processing unit, and plotting the changes of the characteristic response values ​​over time into a graph;

[0011] Analyze the graph to determine the opening and closing times of the electromagnetic reversing valve, calculate the difference between the opening and closing times, and obtain the response time difference Δt;

[0012] The response time difference Δt is substituted into the volume loss calculation model to calculate the standard volume value loss volume when the standard volume value of the volume tube is calibrated, thereby correcting and compensating the standard volume value of the volume tube.

[0013] Beneficial effects of the present invention:

[0014] 1. The high frame rate of the high-speed camera can capture the microsecond-level jitter of the solenoid reversing valve core. Compared with traditional calibration methods, the calibration accuracy of the standard volume value is improved by 2-3 orders of magnitude.

[0015] 2. Using high-speed cameras and image processing technology, the response time difference Δt of the electromagnetic reversing valve is accurately measured, and a flow rate Q-Δt mathematical model is established to reduce fluid loss during standard volume value calibration and achieve quantitative error analysis and compensation.

[0016] 3. The grayscale change curve can intuitively present abnormal conditions such as delay and oscillation of the valve core movement, providing a direct basis for diagnosing the performance degradation of the electromagnetic reversing valve and performing predictive maintenance.

[0017] 4. Replace the complex "fast-slow travel switching" operation in traditional calibration, greatly reduce the intensity of manual intervention, and improve the universality and repeatability of the method.

[0018] In summary, the present invention innovatively measures the response time of the electromagnetic reversing valve when calibrating the standard volume value of the volume tube through the combination of non-contact high-speed visual monitoring and signal precision triggering mechanism, filling the technical gap of traditional methods in ensuring calibration accuracy, and has good engineering practicality and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0020] Figure 1 A flow chart of a method for measuring the response time of an electromagnetic reversing valve provided by an embodiment of the present invention;

[0021] Figure 2 An actuation timing diagram of an electromagnetic reversing valve provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of a system for measuring the effect of the response time of an electromagnetic reversing valve on the calibration of a standard volume value of a volume tube provided by an embodiment of the present invention;

[0023] Figure 4 A comparison diagram of the opening response signals of an electromagnetic reversing valve at different flow rates provided by an embodiment of the present invention;

[0024] Figure 5 A comparison diagram of closing response signals of an electromagnetic reversing valve at different flow rates provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the technical solution of the present invention more clearly understood, the present invention will be further described below in conjunction with the schematic diagram and specific implementation methods of the present invention. It should be understood that the implementation methods described below are only used to illustrate the present invention and are not used to limit the scope of protection of the present invention.

[0026] The present invention proposes a method for directly observing the jitter of the electromagnetic reversing valve core at the opening and closing moments during the calibration of the standard volume value of the volume tube using a high-speed camera, thereby accurately measuring the opening and closing time difference. The present invention introduces high-speed camera technology as an observation means. By accurately capturing and analyzing these high-speed images, the true opening time and closing time of the electromagnetic reversing valve can be actively, objectively and directly measured, abandoning the traditional method's assumption of the symmetry of the opening and closing time difference of the electromagnetic reversing valve and the working condition optimization method. The present invention focuses on the analysis of the impact of the dynamic response characteristics of its core component, the electromagnetic reversing valve, on the calibration of the standard volume value. It uses high-speed camera technology to accurately measure the jitter of the valve during opening and closing in a non-contact manner, and establishes an analytical model for the impact of the response time difference on the calibration results, so as to improve the calibration accuracy of the standard volume value of the volume tube and the reliability of its value transmission.

[0027] Specifically, the present invention first requires connecting a high-speed camera to a proximity switch signal at the control system end, then placing the electromagnetic reversing valve on a mesh plate and starting to calibrate the standard volume value of the volume tube. When the volume tube baffle triggers the proximity detection switch, the high-speed camera start signal is triggered, and the high-speed camera starts shooting, obtaining a jitter image when the electromagnetic reversing valve is open, at which time the medium flows into the measuring cup (which can be used for calibration by mass method). Subsequently, through software processing, the grayscale response value of the electromagnetic reversing valve jitter image is extracted. The program plots the change of the grayscale response value over time into a graph. The graph is analyzed, and the number of frames corresponding to the first peak is the duration of the electromagnetic reversing valve opening. Similarly, when the baffle triggers the end of the proximity detection switch, the camera is triggered again, and the subsequent processing steps are the same, obtaining the duration of the electromagnetic reversing valve closing, at which time the medium flows into the water storage tank. The response time difference Δt is subtracted from this time, and the response time difference Δt is substituted into the volume loss formula for calculation to obtain the standard volume loss volume when calibrating the standard volume value of the volume tube.

[0028] The method for measuring the opening and closing time difference is to obtain a series of grayscale images of the electromagnetic reversing valve positions through a high-speed camera. If the electromagnetic reversing valve jitters due to opening and closing, the grayscale value of the fixed pixel point changes due to the jitter. After post-processing, the grayscale change trend of the selected position over time can be intuitively observed, thereby obtaining the response time difference of the opening and closing of the electromagnetic reversing valve.

[0029] Example:

[0030] Please refer to Figure 1 , Figure 1 A flow chart for calibrating a standard volume value of a volume tube based on the response time of an electromagnetic reversing valve provided in an embodiment of the present invention includes the following steps:

[0031] Step S1: Connect the high-speed camera to the control system end proximity switch signal, place the electromagnetic reversing valve on the mesh plate, and start calibrating the standard volume value of the volume tube.

[0032] Step S2: During the calibration of the standard volume value of the volume tube, the baffle triggers the proximity detection switch of the volume tube, and the high-speed camera starts shooting.

[0033] Step S3: Using a high-speed camera to capture a jitter image of the electromagnetic reversing valve opening and closing.

[0034] Step S4: extracting the grayscale response value of the jitter image of the electromagnetic reversing valve opening and closing through software processing, and the program plots the change of the grayscale response value over time into a graph.

[0035] Step S5: Analyze the graph, and the number of frames corresponding to the first peak is the duration of the opening and closing of the electromagnetic reversing valve.

[0036] Step S6: Subtract the opening and closing time of the electromagnetic reversing valve to obtain a response time difference Δt.

[0037] Step S7: Substitute the response time difference Δt into the volume loss formula for calculation to obtain the standard volume loss volume when the standard volume value of the volume tube is calibrated.

[0038] For details, please refer to Figure 2 , solenoid reversing valve response time diagram. Figure 2 As shown in FIG, when the electromagnetic reversing valve receives an open working signal, the response time is t1; when the electromagnetic reversing valve receives a closed working signal, the response time is t2.

[0039] Furthermore, to measure the response time of the solenoid directional control valve, in this embodiment, a high-speed camera is used to record the complete dynamic process of the solenoid directional control valve, from the moment it receives the opening or closing signal until the valve completes its actuation. By analyzing the images at different times, the specific moments of the solenoid directional control valve's opening and closing can be determined, and the response time of the solenoid directional control valve during calibration of the standard volume value of the volume tube can be derived. The response time difference Δt is then calculated, and substituted into the formula to obtain the standard volume loss volume during calibration of the volume tube.

[0040] Specifically, step S1 includes:

[0041] Step S11: placing the electromagnetic reversing valve on the mesh plate.

[0042] Step S12: Align the setting position of the high-speed camera with the electromagnetic reversing valve (maintain an angle to shoot the electromagnetic reversing valve, and when the electromagnetic reversing valve moves, it will be reflected in the images continuously shot by the high-speed camera).

[0043] Step S13: Record the current reference image with a high-speed camera, thereby achieving the positioning of the high-speed camera and the electromagnetic reversing valve, ensuring the accuracy of subsequent measurements.

[0044] Specifically, step S2 includes:

[0045] Step S21: Connect the high-speed camera to the control system end proximity switch signal.

[0046] Step S22: When the baffle triggers the detection of the proximity switch, the camera start signal is triggered, thereby ensuring the synchronization of the high-speed camera shooting and the operation of the electromagnetic reversing valve, and ensuring the accuracy of the response time measurement.

[0047] Please refer to Figure 3 , which is a schematic diagram of the composition of a measurement system for the influence of the response time of an electromagnetic reversing valve on the calibration of the standard volume value of a volume tube provided by an example of the present invention. The main equipment includes: a volume tube flow standard device 4, a high-speed camera 1, electromagnetic reversing valves 2 and 3, a measuring cup 7, an electronic balance 8, and a water storage tank 9. Two electromagnetic reversing valves are used to connect the two ends of a T-type connector 5, which respectively pass into the measuring cup and the water storage tank.

[0048] During the calibration process, the piston in the volume tube flow standard device 4 moves downstream synchronously with the fluid under the action of the upstream fluid, and the fluid flows to the T-connector 5 through the volume tube outlet 6. When the baffle is triggered to start detecting the proximity switch, the reversing mechanism switches state, the electromagnetic reversing valve 2 opens, and the electromagnetic reversing valve 3 closes. The electromagnetic reversing valve enters the working mode according to the above-mentioned start signal, and the fluid flows into the measuring cup 7, and the electronic balance 8 is weighed. When the baffle is triggered to stop detecting the proximity switch, the electromagnetic reversing mechanism switches state again, the electromagnetic reversing valve 2 closes, the electromagnetic reversing valve 3 opens, and the fluid flows into the water storage tank 9 through the electromagnetic reversing valve 3, and the single calibration test is completed.

[0049] Specifically, in step S3, obtaining the response time of the electromagnetic reversing valve through the image may include:

[0050] Step S31 : obtaining the pixel unit corresponding to the electromagnetic reversing valve 2 in the image.

[0051] Step S32: Determine the moment when the electromagnetic reversing valve 2 vibrates when it is opened as the first moment.

[0052] Step S33: Determine the moment when the electromagnetic reversing valve 2 is closed and jittered as the second moment.

[0053] Step S34: performing a difference operation between the second moment and the first moment to obtain a response time.

[0054] It is understood that an image is composed of multiple pixel units, and the set position of the electromagnetic reversing valve can be represented by a pixel unit. When the electromagnetic reversing valve vibrates, the pixel unit representing the set position of the electromagnetic reversing valve also changes. Therefore, the response time can be determined by the change in the pixel unit.

[0055] Specifically, step S4 includes:

[0056] Step S41: traverse each image file in a loop and extract the grayscale value of the pixel at the predefined coordinate.

[0057] Step S42: The program plots the change of the grayscale response value over time into a graph.

[0058] Please refer to Figure 4 、 Figure 5 , Figure 4 Comparison of flow rate signals when opening electromagnetic reversing valves at different calibrated speeds ((a) in the figure: 0.298m³ / h; (b) in the figure: 0.05m³ / h); Figure 5 Comparison of the closing signals of a solenoid directional valve at different calibrated speeds ((a): 0.298 m³ / h; (b): 0.05 m³ / h). The horizontal axis represents the frame number, while the vertical axis represents the grayscale response value corresponding to a specific position. This allows for intuitive observation of the grayscale change trend at a selected position over time, thereby determining the response time of the solenoid valve's opening and closing.

[0059] Furthermore, the response time difference Δt is used to calculate the standard volume loss during the calibration of the volume tube standard flow rate. The loss volume formula is:

[0060]

[0061] Where: V lose is the standard volume loss due to the response time difference of the electromagnetic reversing valve, in L; Q is the calibrated flow rate of the standard volume of the volume tube, in m³ / h; Δt is the difference between the closing response time and the opening response time of the electromagnetic reversing valve, in s.

[0062] Through the loss volume calculation formula, the influence of different flow rates on the response time difference of the electromagnetic reversing valve is analyzed, the volume loss is reduced, the quantitative analysis and compensation of the error are achieved, and the standard volume value is closer to the actual value.

[0063] In summary, the method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve described in the present invention utilizes a high-speed camera to obtain the opening and closing actuation moment and response time of the electromagnetic reversing valve without changing the original calibration process and system architecture of the standard volume value of a volume tube. It has the advantages of simple structure, strong operability, and non-contact precise measurement, and is easy to be extended to the standard volume value calibration method of the existing piston-type volume tube flow standard device. In addition, the grayscale change curve can intuitively present abnormal states such as delay and oscillation of the electromagnetic reversing valve action, providing a direct basis for the diagnosis of performance degradation of the electromagnetic reversing valve and predictive maintenance, and has good engineering application value and promotion prospects.

[0064] In summary, the preferred embodiments of the present invention are described in detail above based on the embodiments shown in the drawings. However, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve, characterized in that: The following steps are involved: Connect the non-contact measuring device to the control system signal, install the electromagnetic reversing valve on the measuring platform, and start the calibration process of the standard volume value of the volume tube; During the calibration process of the standard volume value of the volume tube, when the volume tube triggers the signal device, the non-contact measuring device is started to obtain a dynamic characteristic image of the moment the electromagnetic reversing valve is opened, and the medium flows into the first measuring container at this time; when the volume tube triggers the signal device again, the non-contact measuring device is started again to obtain a dynamic characteristic image of the moment the electromagnetic reversing valve is closed, and the medium flows into the second measuring container at this time; Extracting characteristic response values ​​of the dynamic characteristic image of the electromagnetic reversing valve through a data processing unit, and plotting the changes of the characteristic response values ​​over time into a graph; Analyze the graph to determine the opening and closing times of the electromagnetic reversing valve, calculate the difference between the opening and closing times, and obtain the response time difference Δt; The response time difference Δt is substituted into the volume loss calculation model to calculate the standard volume value loss volume when the standard volume value of the volume tube is calibrated, thereby correcting and compensating the standard volume value of the volume tube.

2. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 1, characterized in that: The non-contact measuring device is a high-speed camera, and the dynamic characteristic image is a shaking image of the electromagnetic reversing valve core at the moment of opening and closing.

3. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 1, characterized in that: The characteristic response value is a grayscale value of a pixel at a predefined position in the image, and is obtained by looping through each image file and extracting the grayscale value of the pixel at the predefined coordinate.

4. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to any one of claims 1 to 3, characterized in that: The first measuring container is a measuring cup, the second measuring container is a water storage bucket, and the measuring cup is placed on an electronic balance for accurately measuring the volume of the medium flowing into the measuring cup.

5. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 4 is characterized in that: The volume loss calculation model is: Among them, V lose It is the loss volume of the standard volume value caused by the response time difference of the electromagnetic reversing valve; Q is the calibrated flow rate of the standard volume value of the volume tube.

6. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 1 or 2, characterized in that: The frame rate of the non-contact measuring device is not less than 5000 frames per second, so as to ensure that the microsecond-level jitter of the electromagnetic reversing valve core can be accurately captured.

7. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 6, characterized in that: The measuring platform is a mesh plate, and the electromagnetic reversing valve is mounted on the mesh plate through a fixing device to ensure that its position is stable and convenient for measurement.

8. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 1, characterized in that: The signal device is a proximity switch, and the action of the trigger signal device is triggered by the baffle of the volume tube to achieve synchronous measurement with the action of the electromagnetic reversing valve.

9. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 1, characterized in that: The data processing unit includes image processing software and a data analysis program, which is used to extract and analyze the grayscale response value of the dynamic characteristic image of the electromagnetic reversing valve and generate a grayscale change curve.

10. The method for calibrating the standard volume value of a volume tube based on the response time of an electromagnetic reversing valve according to claim 9, characterized in that: The method also includes a step of diagnosing the performance degradation of the electromagnetic reversing valve, and providing a basis for predictive maintenance of the electromagnetic reversing valve by analyzing the delay and oscillation in the grayscale change curve.

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