Control method and system of blow-off valve

Abstract

The invention relates to a control method and system for a blow-off valve. The control method comprises the steps that current signals of a combustion fan are collected for multiple times within each preset time period; for each preset time period, the initial current of each current signal is firstly calculated, then the average current of all the initial currents is calculated, and the operation current is obtained; and calculating a current fluctuation percentage by using the operation current of the two adjacent preset time periods, and adjusting a valve position opening percentage of the blow-off valve according to the current fluctuation percentage. By detecting and analyzing the fluctuation of the current of the combustion fan, the valve position opening degree of the blow-off valve can be accurately adjusted, and the blow-off amount is controlled. Moreover, under the condition that the combustion fan does not surge, the relief valve is adjusted to the minimum valve position opening degree, the relief amount is reduced, the optimal valve position opening degree control state is achieved, and therefore energy waste can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion-supporting fans, and in particular to a control method and system for a relief valve. Background Art

[0002] During normal operation, the combustion-supporting fan's air flow and pressure performance curves should be smoothly ascending, but in reality, they often exhibit a hump-shaped curve. Operation within the hump region can cause surge. Surge occurs primarily because as the fan's load decreases, the fan becomes unstable when the load flow decreases to a certain value while maintaining air pressure. Operating within the hump region, the fan experiences fluctuating flow rates and air pressure, accompanied by strong vibration. Because strong vibration is accompanied by noise, prolonged surge can not only cause mechanical damage but also pose a safety hazard to production.

[0003] To eliminate surge in the combustion fan, a vent valve with automatically controlled opening is typically installed in the fan outlet vent pipe. A controller or other device controls the vent valve's opening based on the load flow. However, due to the non-linear relationship between valve opening and flow, the controller cannot accurately control the vent valve's opening based on the load flow. The controller can only compensate by increasing the vent flow, which still results in energy waste. Summary of the Invention

[0004] Based on the above description, the present invention provides a control method and system for a relief valve, aiming to solve the problem that the existing controller cannot accurately control the valve position opening of the relief valve.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: In a first aspect, a method for controlling a relief valve includes: The current signal of the combustion-supporting fan is collected multiple times within each preset time period; For each of the preset time periods, firstly calculating the initial current of each of the current signals, and then calculating the average current of all the initial currents to obtain the operating current; The current fluctuation percentage is calculated using the operating currents in two adjacent preset time periods, and the valve position opening percentage of the relief valve is adjusted according to the current fluctuation percentage.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the acquisition time of the current signal of the combustion-supporting fan each time is 0-100ms.

[0008] Furthermore, the number of collection times within each preset time period is 0 to 20 times.

[0009] Furthermore, after collecting the current signal of the combustion-supporting fan a preset number of times within each preset time period, the method further includes: Filtering is performed on each of the current signals.

[0010] Furthermore, the calculation formula for the current fluctuation percentage includes: ; Where: F Indicates the current fluctuation percentage; L 1 represents the rated current of the combustion-supporting fan; L 2 indicates the operating current of the combustion-supporting fan during the current preset time period; L 3 represents the operating current of the combustion air blower during the previous preset time period.

[0011] Furthermore, adjusting the valve position opening percentage of the relief valve according to the current fluctuation percentage includes: If the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from a valve position increase percentage range to increase the valve position opening percentage; If the current fluctuation percentage is less than a second preset fluctuation percentage threshold, a valve position opening percentage reduction is determined from the valve position reduction percentage range to reduce the valve position opening percentage.

[0012] Furthermore, if the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from a valve position increase percentage range to increase the valve position opening percentage includes: When the first preset fluctuation percentage threshold is within the first preset fluctuation range, a first increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a second preset fluctuation range, a second increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a third preset fluctuation range, a third increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a fourth preset fluctuation range, a fourth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a fifth preset fluctuation range, a fifth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage.

[0013] Furthermore, determining the valve position opening percentage of the relief valve according to the current fluctuation percentage includes: If the current fluctuation percentage is between the first preset fluctuation percentage threshold and the second preset fluctuation percentage threshold, the valve position opening percentage of the relief valve remains unchanged.

[0014] In a second aspect, a control system for a relief valve is provided. The control system is applicable to the method for controlling a relief valve according to the first aspect, comprising: A current detection element is used to collect the current signal of the combustion-supporting fan multiple times within each preset time period; A controller is electrically connected to the current detection element, and is configured to calculate, for each preset time period, an initial current of each current signal, and then calculate an average current of all the initial currents to obtain an operating current; calculate a current fluctuation percentage using the operating currents of two adjacent preset time periods; and determine a valve position opening percentage of the relief valve based on the current fluctuation percentage.

[0015] Furthermore, a filter is included, which is connected in series between the current detection element and the controller, and is used to filter each current signal.

[0016] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: By detecting and analyzing fluctuations in the combustion-supporting fan current, the present invention can precisely adjust the valve position of the relief valve and control the relief volume. Furthermore, when the combustion-supporting fan is not surging, the relief valve is adjusted to the minimum valve position, reducing the relief volume and achieving optimal valve position control, thereby reducing energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of a method for controlling a relief valve provided in an embodiment of the present invention; Figure 2 A logic diagram of a control method for a relief valve provided in an embodiment of the present invention; Figure 3 The figure is a schematic structural diagram of a control system of a relief valve provided in an embodiment of the present invention.

[0018] Description of reference numerals: 1. Combustion-supporting fan; 2. Discharge valve; 3. Current detection element; 4. Controller; 5. Filter. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0021] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0022] Reference Figures 1 and 2 As shown, the present invention provides a technical solution: a control method for a relief valve, comprising the following steps: S1, collecting the current signal of the combustion-supporting fan 1 multiple times within each preset time period; S2, for each of the preset time periods, first calculating the initial current of each of the current signals, and then calculating the average current of all the initial currents to obtain the operating current; S3, calculating the current fluctuation percentage using the operating currents in two adjacent preset time periods, and adjusting the valve position opening percentage of the relief valve 2 according to the current fluctuation percentage.

[0023] Exemplarily, the relief valve 2 may be a pneumatic butterfly valve or an electric butterfly valve. The preset time period may be 1s, 2s, or 3s, or 1min, 2min, or 3min. The acquisition time of the current signal of the combustion-supporting fan 1 each time is 0 to 100ms. For example, the acquisition time of the current signal of the combustion-supporting fan 1 each time in the present invention is 100ms. The number of acquisitions within each of the preset time periods is 0 to 20 times. For example, the number of acquisitions within each of the preset time periods in the present invention is 10 times.

[0024] In this embodiment, by detecting and analyzing the current fluctuations of the combustion-supporting fan 1, the valve position opening of the relief valve 2 can be precisely adjusted to control the relief amount. Furthermore, when the combustion-supporting fan 1 is not surging, the relief valve 2 is adjusted to the minimum valve position opening to reduce the relief amount and achieve the optimal valve position opening control state, thereby reducing energy waste.

[0025] Reference Figures 1 and 2 As shown, in some embodiments, after S1 , the control method includes filtering each of the current signals.

[0026] In this embodiment, by filtering the current signal, current fluctuations can be reflected more accurately, thereby obtaining a more accurate operating current.

[0027] In some embodiments, the calculation formula for the current fluctuation percentage includes: ; Where: F Indicates the current fluctuation percentage; L 1 represents the rated current of combustion-supporting fan 1; L 2 represents the operating current of the combustion-supporting fan 1 during the current preset time period; L 3 represents the operating current of the combustion-supporting fan 1 during the previous preset time period.

[0028] Reference Figure 2 As shown, in some embodiments, adjusting the valve position opening percentage of the relief valve 2 according to the current fluctuation percentage includes the following steps: If the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from a valve position increase percentage range to increase the valve position opening percentage; If the current fluctuation percentage is less than a second preset fluctuation percentage threshold, a valve position opening percentage reduction is determined from the valve position reduction percentage range to reduce the valve position opening percentage.

[0029] For example, the first preset fluctuation percentage threshold may be 10%, and the second preset fluctuation percentage threshold may be 5%. The valve position increase percentage range may be 0% to 100%, and the valve position decrease percentage range may be 0% to -100%.

[0030] In this embodiment, the valve opening percentage is increased when the current fluctuation percentage of the combustion-supporting fan 1 is large, and is decreased when the current fluctuation percentage of the combustion-supporting fan 1 is small, thereby achieving constant adjustment of the valve opening percentage of the relief valve 2. Furthermore, the first preset fluctuation percentage threshold can be the current fluctuation percentage when the combustion-supporting fan 1 is operating stably, and the second preset fluctuation percentage threshold can be the current fluctuation percentage at which the combustion-supporting fan 1 begins to surge, which serves as a basis for debugging the combustion-supporting fan 1. When the load flow increases, the combustion-supporting fan 1 is no longer surging, and the motor current stabilizes, the valve opening percentage will gradually decrease to 0%.

[0031] Reference Figure 2 As shown, in some embodiments, if the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from a valve position increase percentage range to increase the valve position opening percentage includes: When the first preset fluctuation percentage threshold is within the first preset fluctuation range, a first increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a second preset fluctuation range, a second increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a third preset fluctuation range, a third increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a fourth preset fluctuation range, a fourth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a fifth preset fluctuation range, a fifth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage.

[0032] Exemplarily, the first preset fluctuation range can be 10%~15%, and the first increased opening percentage can be 1%; the second preset fluctuation range can be 15%~20%, and the second increased opening percentage can be 2%; the third preset fluctuation range can be 15%~20%, and the first increased opening percentage can be 3%; the fourth preset fluctuation range can be 20%~25%, and the first increased opening percentage can be 4%; the fifth preset fluctuation range can be 25%~30%, and the first increased opening percentage can be 5%.

[0033] In this embodiment, since the first through fifth preset fluctuation ranges represent a range with a high probability of fluctuation, the first through fifth increments of opening percentage are also commonly used increments of opening percentage. Therefore, by analyzing the preset fluctuation range within which the first preset fluctuation percentage threshold falls, not only can the increment of opening percentage be determined more quickly, but the relief valve 2 can also adjust the valve position opening percentage in a shorter period of time, thereby improving the efficiency of the relief valve 2 in adjusting the valve position opening percentage.

[0034] Reference Figure 2 As shown, in some embodiments, determining the valve position opening percentage of the relief valve 2 according to the current fluctuation percentage includes: If the current fluctuation percentage is between the first preset fluctuation percentage threshold and the second preset fluctuation percentage threshold, the valve position opening percentage of the relief valve 2 remains unchanged.

[0035] Exemplarily, the first preset fluctuation percentage threshold and the second preset fluctuation percentage threshold may be between 5% and 10%.

[0036] In this embodiment, since the current fluctuation impact on the combustion-supporting fan 1 is small when the current fluctuation percentage is between the first preset fluctuation percentage threshold and the second preset fluctuation percentage threshold, the valve position opening percentage of the relief valve 2 in this interval remains unchanged.

[0037] Reference Figure 3 As shown, the present invention provides a technical solution: a control method for a relief valve, a control system for a relief valve, the control system is suitable for the control method of a relief valve according to the above-mentioned method, including a current detection element 3 and a controller 4, the current detection element 3 is used to collect the current signal of the combustion-supporting fan 1 multiple times within each preset time period; the controller 4 is electrically connected to the current detection element 3, and the controller 4 is used to calculate the initial current of each current signal for each preset time period, and then calculate the average current of all the initial currents to obtain the operating current, use the operating current of two adjacent preset time periods to calculate the current fluctuation percentage, and determine the valve position opening percentage of the relief valve 2 according to the current fluctuation percentage.

[0038] For example, the current detection element 3 may be a current transformer or a sampling resistor, etc. The controller 4 may be a PLC controller 4 or an FPGA controller 4, etc.

[0039] Reference Figure 3 As shown, in some embodiments, a filter 5 is included, and the filter 5 is connected in series between the current detection element 3 and the controller 4. The filter 5 is used to filter each of the current signals.

[0040] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A control method for a relief valve, characterized in that: include: Collecting the current signal of the combustion-supporting fan multiple times within each preset time period; For each of the preset time periods, firstly calculate the initial current of each of the current signals, and then calculate the average current of all the initial currents to obtain the operating current; The current fluctuation percentage is calculated using the operating currents of two adjacent preset time periods, and the valve position opening percentage of the relief valve is adjusted according to the current fluctuation percentage.

2. A method for controlling a relief valve according to claim 1, characterized in that: The acquisition time of the current signal of the combustion-supporting fan each time is 0-100ms.

3. A method for controlling a relief valve according to claim 1, characterized in that: The number of collections within each of the preset time periods is 0 to 20 times.

4. A method for controlling a relief valve according to claim 1, characterized in that: After collecting the current signal of the combustion-supporting fan at a preset number of times within each preset time period, the method includes: A filtering process is performed on each of the current signals.

5. A method for controlling a relief valve according to claim 1, characterized in that: The calculation formula of the current fluctuation percentage includes: ； Where: F Indicates the current fluctuation percentage; L 1 indicates the rated current of the combustion-supporting fan; L 2 indicates the operating current of the combustion-supporting fan during the current preset time period; L 3 represents the operating current of the combustion-supporting fan during a preset time period.

6. A method for controlling a relief valve according to claim 1, characterized in that: The step of adjusting the valve position opening percentage of the relief valve according to the current fluctuation percentage includes: If the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from the valve position increase percentage range to increase the valve position opening percentage; If the current fluctuation percentage is less than the second preset fluctuation percentage threshold, a reduction opening percentage is determined from the valve position reduction percentage range to reduce the valve position opening percentage.

7. A method for controlling a relief valve according to claim 6, characterized in that: If the current fluctuation percentage is greater than a first preset fluctuation percentage threshold, determining an increase opening percentage from a valve position increase percentage range to increase the valve position opening percentage includes: When the first preset fluctuation percentage threshold is within the first preset fluctuation range, a first increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within the second preset fluctuation range, a second increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a third preset fluctuation range, a third increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within a fourth preset fluctuation range, a fourth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage; When the first preset fluctuation percentage threshold is within the fifth preset fluctuation range, a fifth increase opening percentage is determined from the valve position increase percentage range to increase the valve position opening percentage.

8. A method for controlling a relief valve according to claim 7, characterized in that: Determining the valve position opening percentage of the relief valve according to the current fluctuation percentage includes: If the current fluctuation percentage is between the first preset fluctuation percentage threshold and the second preset fluctuation percentage threshold, the valve position opening percentage of the relief valve remains unchanged.

9. A control system for a relief valve, characterized in that: The control system is applicable to a control method for a relief valve according to any one of claims 1 to 8, comprising: A current detection element, used to collect the current signal of the combustion-supporting fan multiple times within each preset time period; A controller is electrically connected to the current detection element, and is used to calculate, for each preset time period, first an initial current of each current signal, then calculate an average current of all the initial currents to obtain an operating current, calculate a current fluctuation percentage using the operating currents of two adjacent preset time periods, and determine a valve position opening percentage of the relief valve according to the current fluctuation percentage.

10. A control system for a relief valve according to claim 9, characterized in that: A filter is included, which is connected in series between the current detection element and the controller, and is used to filter each current signal.

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