Control method of high-frequency-response wide-range dynamic flow generation device

Abstract

The invention relates to valve electric control, in particular to a high-frequency-response wide-range dynamic flow generation device control method, which comprises a stable flow setting step, a parameter acquisition step, a dynamic flow constant flow scheme determination step, a stability calculation step and a valve adjustment step. According to the dynamic flow generation device composed of the multiple branch sonic nozzles with different throat diameters, the dynamic flow generation device can select different sonic nozzles according to the required flow value to be detected to achieve the flow value to be detected, and the flow precision of the dynamic flow generation device is improved. Asynchronous switching is carried out on the high-speed switching valves, the starting sequence and the interval time of the high-speed switching valves are set according to the time that the high-speed switching valves can achieve stable output flow, and therefore flow fluctuation generated when the valve state of the high-speed switching valves changes is eliminated, and the stability of the high-speed switching valves is improved. And the response speed and the flow generation precision of the dynamic flow generation device are improved.

Description

Technical Field

[0001] The present invention relates to the field of flow generating devices, and specifically to a control method for a high-frequency response wide-range dynamic flow generating device. Background Art

[0002] In the electrical control of valves, a dynamic flow generating device is a key equipment for testing the performance of flow meters. Traditional dynamic flow generating devices have certain limitations in terms of flow range and response speed, and it is difficult to meet the requirements of modern industry for high-precision, wide-range, and fast-response flow tests. Especially in scenarios where dynamic flow changes need to be simulated, traditional devices often have difficulty accurately and stably generating the required flow changes, thus affecting the test accuracy and reliability of flow meters.

[0003] In addition, existing dynamic flow generating devices also have deficiencies in flow control. Due to the fluctuations and unstable factors during the flow change process, it is difficult for the device to maintain a constant flow value when outputting flow, which is a significant problem for occasions that require high-precision flow control.

[0004] Therefore, in order to solve the above problems and improve the flow accuracy, response speed, and stability of the dynamic flow generating device, the present invention proposes a control method for a high-frequency response wide-range dynamic flow generating device. Summary of the Invention

[0005] In order to solve the problems in the above-mentioned prior art, the first object of the present invention is to provide a control method for a high-frequency response wide-range dynamic flow generating device. By using multiple groups of dynamically switched dynamic flow generating branches to form a flow generating matrix and regulating the flow generating branches connected to the flow meter to be tested according to the required flow size, the problems of slow response and inability to flexibly adjust the flow value to be tested of the existing flow generating device are solved, and the beneficial effects of improving the control accuracy and response speed of the flow generating device are achieved.

[0006] To achieve the above object, the solution provided by the present invention is: A control method for a high-frequency response wide-range dynamic flow generating device, including: A stable flow setting step, opening all switching valves, opening all high-speed switching valves to the untested state, turning on the gas source and adjusting the device temperature and pipeline pressure to make all sonic nozzles reach the critical constant flow state; A parameter acquisition step, setting the dynamic flow value to be tested, selecting the high-speed switching valve according to the set dynamic flow value to be tested and adjusting it to the tested state, and acquiring the start-up time required for the flow meter to be tested to reach the set dynamic flow value to be tested; Steps for determining the dynamic flow constant flow scheme: Detect and obtain the flow fluctuation value when the high-speed switching valve changes its state. Determine the high-speed switching valve with a valve state change according to the dynamic flow value to be detected. Calculate the stabilization time for the flow to reach stability after the valve switching of each high-speed switching valve based on the flow fluctuation value and the starting time. Stability calculation steps: Calculate the opening time and closing time of the high-speed switching valve that needs to switch its valve according to the stabilization time and the magnitude of the flow fluctuation value. Calculate the flow stability value when the high-speed switching valve switches asynchronously. Compare the magnitude of the flow stability value with the set threshold, and calculate the difference to obtain the flow stability difference. Valve adjustment steps: When the flow stability value is less than the threshold, calculate the flow fluctuation value influence factor according to the flow stability difference. Recalculate the stabilization time of the high-speed switching valve through the flow fluctuation value influence factor, and calculate the opening time and closing time of the high-speed switching valve.

[0007] By using a dynamic flow generating device composed of sonic nozzles with different throat diameters in multiple branches, the dynamic flow generating device can select different sonic nozzles according to the magnitude of the flow value to be detected to achieve the flow value to be detected, improving the flow accuracy of the dynamic flow generating device. By performing asynchronous switching on the high-speed switching valve and setting the start sequence and interval time of the high-speed switching valve according to the time when the high-speed switching valve can reach a stable output flow, the flow fluctuation during the valve state change of the high-speed switching valve is eliminated, improving the response speed and flow generation accuracy of the dynamic flow generating device.

[0008] As a further improvement of the present invention, the high-frequency response wide-range dynamic flow generating device is provided with a number of sonic nozzles with different throat diameters. The flow value of the sonic nozzle is determined by the throat diameter of the sonic nozzle, and a number of different output flow values are obtained by combining a number of sonic nozzles with different flow values. By using sonic nozzles with different flow magnitudes to control the flow value of the dynamic flow generating device, the flow accuracy of the dynamic flow generating device is improved, and the output flow range of the dynamic flow generating device is expanded.

[0009] As a further improvement of the present invention, in the step of determining the dynamic flow constant flow scheme, according to the magnitude of the dynamic flow value to be detected, a sonic nozzle connected to the flowmeter to be detected is selected, and the valve of the high-speed switching valve connected to the sonic nozzle is switched to the detection state. And based on the flow fluctuation value when the selected high-speed switching valve is switched and the stabilization time for the flow at the valve port connecting the high-speed switching valve and the flowmeter to be detected to reach a stable flow, the opening sequence of each high-speed switching valve at this dynamic flow value to be detected is determined. By adjusting the opening sequence of the valves of the high-speed switching valve, the stability of the dynamic flow generating device when the flow through the valves of the high-speed switching valve changes is improved, and it can quickly respond and adjust the flow magnitude, thereby enhancing the stability of the dynamic flow generating device.

[0010] As a further improvement of the present invention, the flow fluctuation values are as follows: ; wherein, F ω (t) is the flow fluctuation value function, f(t) is the actual flow function, f s is the flow value when the flow through the high-speed switching valve reaches a stable state, T s is the start time, β is the flow fluctuation value decay rate, and T is the detection time.

[0011] As a further improvement of the present invention, the stabilization time is as follows: ; wherein, M represents the stabilization time, T s is the start time, T c is the critical time when the set flow starts to stabilize, T c is a constant, e is the constant exponent, k is the growth rate at different flows, and α is the decay rate.

[0012] As a further improvement of the present invention, in the stability calculation step, according to the stabilization time and the flow fluctuation value, the opening sequence of the high-speed switching valve is determined, and all high-speed switching valves are sequentially switched according to the opening sequence; the stabilization time for the high-speed switching valve to reach a stable state is calculated through the stabilization time and the flow fluctuation value, and based on the comparison of the magnitude of the flow stable value and the threshold value, when the flow stable value is lower than the threshold value, at this time the dynamic flow generating device is in an abnormal state. The flow stable difference is obtained by taking the difference between the flow stable value and the threshold value, and the influence of the actual flow change on the flow fluctuation value is calculated according to the flow stable difference to obtain the flow fluctuation value influence factor.

[0013] As a further improvement of the present invention, the flow stable value is as follows:

[0014] Among them, S is the stable flow value, and it is the flow fluctuation value switched at the i-th moment.

[0015] As a further improvement of the present invention, after substituting the flow fluctuation influence factor into the flow fluctuation value function again to recalculate the flow fluctuation value in the valve adjustment step, the opening timing of the high-speed switching valve is recalculated according to the recalculated flow fluctuation value and the stable time.

[0016] As a further improvement of the present invention, the high-frequency response wide-range dynamic flow generating device converts the calculated opening timing into an electrical signal, controls the switching of the high-speed switching valve through a PLC, and improves the control accuracy of the high-speed switching valve by using the PLC to control the valve switching.

[0017] The beneficial effects of the present invention are: By using a dynamic flow generating device composed of sonic nozzles with different throat diameters in multiple branches, the dynamic flow generating device can select different sonic nozzles according to the required flow value to be detected to achieve the flow value to be detected, improving the flow accuracy of the dynamic flow generating device. By performing asynchronous switching on the high-speed switching valve and setting the start sequence and interval time of the high-speed switching valve according to the time when the high-speed switching valve can reach a stable output flow, the flow fluctuation when the valve state of the high-speed switching valve changes is eliminated, and the response speed and flow generation accuracy of the dynamic flow generating device are improved. Description of the Drawings

[0018] Figure 1 is a method flow chart of a control method for a high-frequency response wide-range dynamic flow generating device of the present invention.

[0019] Figure 2 is a schematic diagram of the device of the dynamic flow generating device in the embodiment of the present invention.

[0020] Figure 3 is a range curve of the flow value to be detected in the embodiment of the present invention. Detailed Embodiments

[0021] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described here are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0022] An embodiment of the present invention provides a control method for a high-frequency response wide-range dynamic flow generating device, including: Stable flow setting steps: The high-frequency response wide-range dynamic flow generating device is provided with a number of sonic nozzles with different throat diameters. The flow value of the sonic nozzle is determined by the throat diameter of the sonic nozzle, and a number of different output flow values are obtained through the combination of a number of sonic nozzles with different flow values. Open all the switching valves and turn all the high-speed switching valves to the untested state. The high-speed switching valve is a three-channel switching valve, and its valves include an intake valve, a recovery valve, and a detection valve. When the high-speed switching valve is in the untested state, the intake valve and the recovery valve of the high-speed switching valve are open, and the detection valve is closed. Open the gas source and adjust the device temperature and pipeline pressure to make all the sonic nozzles reach the critical constant flow state. Detect the flow value of each sonic nozzle when it reaches the critical constant flow state through a flowmeter, and convert the flow value into an electrical signal data and feedback it to the controller; Parameter acquisition steps: Set the dynamic flow value to be tested. Select the high-speed switching valve according to the set dynamic flow value to be tested and adjust it to the test state. When the high-speed switching valve is adjusted to the test state, the high-speed switching valve goes through a process from the recovery valve being open and the detection valve being closed to the recovery valve being closed and the detection valve being open. Due to the switching of the valves, the flow rate of the sonic nozzle connected to the high-speed switching valve passing through the flowmeter will have a short-term fluctuation. At this time, obtain the start-up time required for the flowmeter under test to reach the set dynamic flow value to be tested, and feedback the start-up time to the controller; Dynamic flow constant flow scheme determination steps: Detect and obtain the flow fluctuation value when the high-speed switching valve valve switches, and feedback the flow fluctuation value to the controller. Determine the high-speed switching valve where the valve state changes according to the dynamic flow value to be tested. Calculate the stable time for the flow value passing through the flowmeter to reach stability after the valve switching of each high-speed switching valve according to the flow fluctuation value and the start-up time. In this step, select the sonic nozzle connected to the flowmeter under test according to the size of the dynamic flow value to be tested, and switch the valve of the high-speed switching valve connected to the sonic nozzle to the test state. Determine the opening sequence of each high-speed switching valve at the dynamic flow value to be tested through the flow fluctuation value when the valve of the selected high-speed switching valve switches and the stable time for the flow rate at the valve port connecting the high-speed switching valve and the flowmeter under test to reach the stable flow; Specifically, referring to Figures 1 to 3 as shown, the flow fluctuation values are: ; Among them, Fω(t) is the flow fluctuation value function, f(t) is the actual flow function, fs is the flow value when the flow reaches the stable state after passing through the high-speed switching valve, Ts is the startup time, β is the attenuation rate of the flow fluctuation value, and T is the detection time. By using this flow fluctuation function, according to the difference between the actual flow function and the stable flow value, considering the attenuation of the flow fluctuation over time, the flow fluctuation value of the flow generating branch is calculated, and this flow fluctuation value is fed back to the controller of the flow generating device, and subsequent calculations are performed to obtain the stable time for controlling the high-speed switching valve of the high-frequency response flow generating device.

[0023] Specifically, referring to Figures 1 to 3 as shown, the stable time is: ; Among them, M represents the stable time, Ts is the startup time, Tc is the critical time when the set flow starts to stabilize, Tc is a constant, e is the constant exponent, k is the growth rate at different flows, and α is the attenuation rate. The stable time is calculated through the startup time and the time for the flow of the sonic nozzle to reach stability, and a control signal for adjusting the high-frequency response flow generating device is generated through the stable time. After receiving the control signal, the high-frequency response flow generating device controls the high-speed switching valve.

[0024] Stability calculation steps: Calculate the opening time and closing time of the high-speed switching valve that needs to be switched according to the stable time and the magnitude of the flow fluctuation value, calculate the flow stability value when the high-speed switching valve is asynchronously switched, compare the magnitude of the flow stability value with the set threshold, and take the difference to obtain the flow stability difference; The stability calculation steps: Determine the opening timing of the high-speed switching valve according to the stable time and the flow fluctuation value, and sequentially switch all high-speed switching valves according to the opening timing; Calculate the stable time for the high-speed switching valve to reach the stable state through the stable time and the flow fluctuation value, and compare according to the magnitude of the flow stability value and the threshold. When the flow stability value is lower than the threshold, at this time, the dynamic flow generating device is in an abnormal state. Take the difference between the flow stability value and the threshold to obtain the flow stability difference, and calculate the influence of the actual flow change on the flow fluctuation value according to the flow stability difference to obtain the flow fluctuation value influence factor.

[0025] The flow stability value is:

[0026] Among them, S is the flow stability value, is the flow fluctuation value switched at the i-th moment.

[0027] Valve adjustment steps: when the stable flow value is less than the threshold, calculate the flow fluctuation value impact factor according to the stable flow difference, recalculate the stable time of the high-speed switching valve through the flow fluctuation value impact factor, and calculate the opening time and closing time of the high-speed switching valve.

[0028] Specifically, in the valve adjustment steps, the flow fluctuation impact factor is substituted into the flow fluctuation value function again to recalculate the flow fluctuation value. Then, according to the recalculated flow fluctuation value and the stable time, the opening timing of the high-speed switching valve is recalculated.

[0029] In this embodiment, as shown in Figures 1 to 3 the high-frequency response wide-range dynamic flow generating device converts the calculated opening timing into an electrical signal, controls the switching of the high-speed switching valve through PLC, and improves the control accuracy of the high-speed switching valve by using PLC to control the valve switching.

[0030] The basic features, principles and advantages of the present invention have been shown and described above. It should be noted that the present invention is not limited by the above embodiments, but only some embodiments. Without departing from the spirit and scope of the present invention, several improvements and supplements made are regarded as the protection scope of the present invention.

Claims

1. A control method for a high-frequency response and wide-range dynamic flow generating device, characterized in that: include: The stable flow setting steps are as follows: open all the switch valves, and open all the high-speed switching valves to the unchecked state, turn on the gas source and adjust the device temperature and pipeline pressure to make all the sonic nozzles reach the critical constant flow state; The parameter acquisition step is to set the dynamic flow value to be tested, select the high-speed switching valve according to the set dynamic flow value to be tested and adjust it to the detection state, and obtain the start-up time required for the flow meter to reach the set dynamic flow value to be tested; The dynamic flow constant flow scheme determination step includes detecting and obtaining the flow fluctuation value when the high-speed switching valve is switched, determining the high-speed switching valve having a valve state change according to the dynamic flow value to be detected, and calculating the stabilization time for the flow of each high-speed switching valve to reach a stable state after the valve is switched according to the flow fluctuation value and the start-up time; A stability calculation step, calculating the opening timing of the high-speed switching valve that needs to be switched according to the stabilization time and the flow fluctuation value, calculating the flow stability value when the high-speed switching valve is switched asynchronously, comparing the flow stability value with the set threshold, and making a difference to obtain a flow stability difference; Valve adjustment step: when the flow stability value is less than the threshold value, the flow fluctuation value influence factor is calculated according to the flow stability difference, the stabilization time of the high-speed switching valve is calculated again through the flow fluctuation value influence factor, and the opening timing of the high-speed switching valve under the range flow value is calculated.

2. A control method for a high-frequency response and wide-range dynamic flow generating device according to claim 1, characterized in that: The high-frequency response and wide-range dynamic flow generating device is provided with a plurality of sonic nozzles with different throat diameters. The flow value of the sonic nozzle is determined by the throat diameter of the sonic nozzle, and a plurality of different output flow values ​​are obtained by combining a plurality of sonic nozzles with different flow values.

3. According to claim 1, a method for controlling a high-frequency response and wide-range dynamic flow generating device is characterized in that: The step of determining the dynamic flow constant flow scheme is to select a sonic nozzle connected to the flow meter to be tested according to the size of the dynamic flow value to be tested, and switch the high-speed switching valve connected to the sonic nozzle to a detection state, and determine the timing of opening each high-speed switching valve under the dynamic flow value to be tested according to the flow fluctuation value when the selected high-speed switching valve is switched and the stabilization time for the flow at the valve port connected to the high-speed switching valve and the flow meter to be tested to reach a stable flow.

4. A control method for a high-frequency response and wide-range dynamic flow generating device according to claim 1, characterized in that: The flow fluctuation values ​​are: ； Among them, F ω (t) is the flow fluctuation function, f(t) is the actual flow function, and f s T is the flow value when the flow through the high-speed switching valve reaches a stable state. s is the start-up time, β is the flow fluctuation value attenuation rate, and T is the detection time.

5. According to claim 1, a method for controlling a high-frequency response and wide-range dynamic flow generating device is characterized in that: The stabilization times are: ； Where M represents the stabilization time, T s is the start-up time, T c T is the critical time for the set flow to stabilize. c is a constant, e is a constant exponent, k is the growth rate under different flow rates, and α is the decay rate.

6. The control method of a high-frequency response wide-range dynamic flow generating device according to claim 1, characterized in that: The stability calculation step determines the opening timing of the high-speed switching valve according to the stabilization time and the flow fluctuation value, and switches all high-speed switching valves in sequence according to the opening timing; calculates the stabilization time for the high-speed switching valve to reach a stable state through the stabilization time and the flow fluctuation value, and compares the flow stability value with the threshold. When the flow stability value is lower than the threshold, the dynamic flow generating device is in an abnormal state. The flow stability difference is obtained by subtracting the flow stability value from the threshold. The influence of the actual flow change on the flow fluctuation value is calculated based on the flow stability difference to obtain the flow fluctuation value influencing factor.

7. A control method for a high-frequency response and wide-range dynamic flow generating device according to claim 6, characterized in that: The flow stability values ​​are: ； Where S is the flow stability value, is the traffic fluctuation value switched at time i.

8. The control method of a high-frequency response and wide-range dynamic flow generating device according to claim 1, characterized in that: The valve adjustment step substitutes the flow fluctuation influencing factor into the flow fluctuation value function again to recalculate the flow fluctuation value, and then recalculates the opening timing of the high-speed switching valve according to the recalculated flow fluctuation value and stabilization time.

9. A control method for a high-frequency response and wide-range dynamic flow generating device according to claim 8, characterized in that: The high-frequency response and wide-range dynamic flow generating device converts the calculated opening timing into an electrical signal, and controls the switching of the high-speed switching valve through a PLC.

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