A flow control method for a formic acid proportional valve and an online vacuum welding furnace

Abstract

The present invention relates to the technical field of formic acid proportional valve flow control, and discloses a flow control method of a formic acid proportional valve and an online vacuum welding furnace. No flow meter is provided on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the opening of the formic acid proportional valve is adjusted in real time to control the flow of formic acid flowing into the vacuum chamber to be constant. The flow control method includes: calculating the average pressure difference of the vacuum chamber; calculating the real-time pressure difference of the vacuum chamber; obtaining the standby pressure parameter; applying the calibration parameter to calibrate the standby pressure parameter in real time so that the standby pressure parameter is infinitely close to the calibration parameter at each moment; optimizing the standby pressure parameter according to the calibration parameter; and calculating the opening of the formic acid proportional valve. The online vacuum welding furnace provided by the present invention does not provide a flow meter on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the flow control method of the formic acid proportional valve is used to control the formic acid flow. The present invention can accurately control the formic acid flow while ensuring that formic acid does not leak.

Description

Technical Field

[0001] The present invention relates to the technical field of formic acid proportional valve flow control, and in particular to a formic acid proportional valve flow control method and an online vacuum welding furnace. Background Art

[0002] Currently, most flow meters on the market are not acid-resistant. Using such flow meters to control the flow of acidic substances such as formic acid significantly shortens the flowmeter's lifespan and also poses the risk of formic acid leakage. Using ordinary valves also makes it difficult to accurately control the formic acid flow rate.

[0003] When using a formic acid furnace for welding, in order to ensure the welding effect, the formic acid flow rate must be accurately controlled, and there must be no hidden dangers of formic acid leakage. Therefore, it is urgent to propose a method that can accurately control the formic acid flow rate while ensuring that formic acid does not leak. Summary of the Invention

[0004] The present invention aims to address the current situation in which the life of an acid-insensitive flowmeter used to control the flow of acidic substances such as formic acid is greatly shortened and there is a risk of formic acid leakage. Furthermore, the flow of formic acid cannot be accurately controlled using ordinary valves. The present invention provides a flow control method for a formic acid proportional valve and an online vacuum welding furnace, which can accurately control the formic acid flow while ensuring that formic acid does not leak.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a flow control method for a formic acid proportional valve. No flow meter is set on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is set, and the opening of the formic acid proportional valve is adjusted in real time. The flow rate of formic acid flowing into the vacuum chamber is controlled to be constant; the flow rate control method includes the following steps:

[0007] S10. Calculate the average pressure difference of the vacuum chamber ;

[0008] S11. Calculate the real-time pressure difference of the vacuum chamber ;

[0009] S12. Obtaining the backup pressure parameters based on the relationship curve between formic acid tank pressure and filling time ;

[0010] S13. Calculate the opening of the formic acid proportional valve ,Right now ,in, Set flow rate for the vacuum chamber.

[0011] As a possible implementation, S10 includes the following sub-steps:

[0012] S100. Read the initial pressure of the vacuum chamber using the vacuum gauge ;

[0013] S101. Configure the stop pressure of the vacuum chamber ;

[0014] S102. Configure the set flow rate of the vacuum chamber ;

[0015] S103. Calculate the average pressure difference of the vacuum chamber ,in, is the volume of the vacuum chamber.

[0016] As a possible implementation, S11 includes the following sub-steps:

[0017] S110. Read real-time pressure value through vacuum gauge and remaining time ,time left From the initial pressure To stop pressure time difference;

[0018] S111. Calculate the real-time pressure difference of the vacuum chamber .

[0019] As a possible implementation, applying the calibration parameters Real-time calibration of standby pressure parameters , so that the backup pressure parameters at each moment Infinitely close to the calibration parameters , the calibration parameters are calculated as follows :

[0020]

[0021] in, is the measured value of the formic acid tank from 0 mbar to the maximum pressure; The measured value of the formic acid tank pressure from 0 mbar to the maintenance pressure; is the real-time pressure of the formic acid tank; is the deviation of the formic acid proportional valve.

[0022] As a possible implementation, according to the calibration parameters Optimize backup pressure parameters , the optimization method is as follows:

[0023] when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is slow at first and then fast. At this time, the opening of the formic acid proportional valve is controlled to be large at first and then small.

[0024] when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is first fast and then slow. At this time, the opening of the formic acid proportional valve is controlled to be small first and then large.

[0025] when When the formic acid is filled into the formic acid tank, the flow rate is constant. At this time, the opening of the formic acid proportional valve is kept unchanged.

[0026] As a possible implementation, the electrical parameters of the formic acid proportional valve are: operating voltage: 12-24V DC, voltage tolerance: ±10%, residual ripple: <5%, power consumption: 1W, output current: Max. 2A, input signal: 0-20mA, 4-20mA or 0-5V, 0-10V, input impedance for current input: <200Ω, input impedance for voltage input: >20kΩ, output signal: PWM signal, frequency range 80Hz-6kHz.

[0027] As a possible implementation, the ambient temperature of the formic acid proportional valve is -10°C to 60°C.

[0028] As a possible implementation method, the functional parameters of the formic acid proportional valve include a rise time function, which is specifically adjustable from 0 to 10 seconds;

[0029] The formic acid proportional valve is installed in the form of a cable plug, which is used for direct valve installation. The protection level of the formic acid proportional valve is IP65; the DIN rail installation type is IP40.

[0030] The valve body material of formic acid proportional valve is: cable plug type is polyamide or PC; DIN rail mounting type is polyamide or PBT.

[0031] As a possible implementation method, the pressure in the formic acid tank is always maintained at 0.8 to 1.2 MPa.

[0032] In a second aspect, the present invention provides an online vacuum welding furnace, in which no flow meter is provided on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the flow control method of the formic acid proportional valve provided in the first aspect is used to control the formic acid flow.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The flow control method for a formic acid proportional valve provided by the present invention eliminates the need for a flow meter, thereby avoiding the impact of acidic liquid on the life of the flow meter and the risk of formic acid leakage that would otherwise occur when using a flow meter, thereby greatly improving reliability and safety.

[0035] 2. The flow control method for a formic acid proportional valve provided by the present invention does not require a flow meter on the pipeline between the formic acid tank and the vacuum chamber, but only a formic acid proportional valve. The formic acid proportional valve has excellent formic acid resistance and is more suitable for flow control of acidic substances such as formic acid compared to traditional flow meters, effectively avoiding the risk of formic acid leakage.

[0036] 3. The flow control method of the formic acid proportional valve provided by the present invention achieves the purpose of precisely controlling the formic acid flow by maintaining a constant flow rate of formic acid flowing into the vacuum chamber through real-time calculation and adjustment of the opening of the formic acid proportional valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 Flow chart of a flow control method of a formic acid proportional valve in an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the calculation process of the formic acid proportional valve in an embodiment of the present invention;

[0040] Figure 3 The pressure curve obtained by actual measurement is shown in the embodiment of the present invention, in which the formic acid flow rate of the vacuum chamber is set to 40 L / min.

[0041] Figure 4 The pressure curve obtained by actual measurement is shown in the embodiment of the present invention, in which the formic acid flow rate of the vacuum chamber is set to 60 L / min. DETAILED DESCRIPTION

[0042] To facilitate a clear description of the technical solutions of the embodiments of the present invention, the words "first" and "second" are used in the embodiments of the present invention to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are merely used to distinguish between different thresholds and do not limit their order. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0043] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0044] In the present invention, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. The following at least one item (item) or similar expressions refers to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (item) of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or plural.

[0045] Most existing flowmeters are not acid-resistant. Using such flowmeters to control the flow of acidic substances such as formic acid significantly shortens the meter's lifespan and poses the risk of formic acid leakage. Accurately controlling the formic acid flow rate is difficult using conventional valves. The present invention aims to provide a flow control method for a formic acid proportional valve and an online vacuum welding furnace that precisely control the formic acid flow rate while preventing formic acid leakage.

[0046] In the first aspect, the embodiment of the present invention provides a flow control method for a formic acid proportional valve, in which no flow meter is provided on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the opening of the formic acid proportional valve is adjusted in real time. Control the flow of formic acid into the vacuum chamber to be constant;

[0047] As a possible implementation, the electrical parameters of the formic acid proportional valve are: operating voltage: 12-24V DC, voltage tolerance: ±10%, residual ripple: <5%, power consumption: 1W, output current: Max. 2A, input signal: 0-20mA, 4-20mA or 0-5V, 0-10V, input impedance for current input: <200Ω, input impedance for voltage input: >20kΩ, output signal: PWM signal, frequency range 80Hz-6kHz.

[0048] As a possible implementation, the ambient temperature of the formic acid proportional valve is -10°C to 60°C, for example, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C.

[0049] As a possible implementation method, the functional parameters of the formic acid proportional valve include a rise time function, which is specifically adjustable from 0 to 10 seconds; the formic acid proportional valve is installed in a cable plug type for direct valve installation; the protection level of the formic acid proportional valve is IP65; the DIN rail mounting type is IP40; the valve body material of the formic acid proportional valve is: polyamide or PC for the cable plug type; polyamide or PBT for the DIN rail mounting type.

[0050] As one possible implementation, the pressure in the formic acid tank is consistently maintained between 0.8 and 1.2 MPa, for example, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, or 1.2 MPa. This configuration allows nitrogen to be introduced when the pressure in the formic acid tank falls below 0.8 MPa, and nitrogen injection is stopped when the pressure in the formic acid tank exceeds 1.2 MPa. When the pressure is consistently maintained between 0.8 and 1.2 MPa, the pressure in the formic acid tank is stable, and the formic acid flow rate also tends to be stable.

[0051] Formic acid proportional valves have excellent formic acid resistance and are more suitable for controlling the flow of acidic substances such as formic acid compared to traditional flow meters. However, formic acid proportional valves typically have a set opening, meaning they output the same amount of fluid as a given opening, making it difficult to adjust the formic acid flow rate in real time. Therefore, embodiments of the present invention propose the following flow control method, which achieves precise control of the formic acid flow rate by calculating and adjusting the opening of the formic acid proportional valve in real time.

[0052] See also Figure 1 , the flow control method includes the following steps:

[0053] S10. Calculate the average pressure difference of the vacuum chamber ;

[0054] As a possible implementation, S10 includes the following sub-steps:

[0055] S100. Read the initial pressure of the vacuum chamber using the vacuum gauge ;

[0056] S101. Configure the stop pressure of the vacuum chamber ;

[0057] S102. Configure the set flow rate of the vacuum chamber ;

[0058] S103. Calculate the average pressure difference of the vacuum chamber ,in, is the volume of the vacuum chamber.

[0059] S11. Calculate the real-time pressure difference of the vacuum chamber ;

[0060] As a possible implementation, S11 includes the following sub-steps:

[0061] S110. Read real-time pressure value through vacuum gauge and remaining time ,time left From the initial pressure To stop pressure time difference;

[0062] S111. Calculate the real-time pressure difference of the vacuum chamber .

[0063] S12. Obtaining the backup pressure parameters based on the relationship curve between formic acid tank pressure and filling time ;

[0064] As an example, record the opening of the formic acid proportional valve at different pressures in the formic acid tank When the vacuum chamber is under negative pressure Charge to normal pressure Time required Through multiple tests, it was found that the formic acid tank pressure is inversely proportional to the vacuum chamber filling time, that is, the greater the formic acid tank pressure, the shorter the filling time. The slope of the formic acid tank pressure and filling time relationship curve is calculated to be the standby pressure parameter. .

[0065] In practical applications, the formic acid flow rate needs to be precisely controlled, and it is usually hoped that the formic acid flow rate output from the formic acid tank is constant. However, since formic acid is charged into the formic acid tank with nitrogen and then charged into the vacuum chamber, the pressure in the formic acid tank is unstable (nitrogen is charged in and out), so the formic acid flow rate charged into the vacuum chamber will also be unstable, which also makes the formic acid flow rate output to the user unstable. Therefore, real-time calibration and optimization of the backup pressure parameters are required. , so that the flow of formic acid entering the vacuum chamber remains constant.

[0066] As a possible implementation, applying the calibration parameters Real-time calibration of standby pressure parameters , so that the backup pressure parameters at each moment Infinitely close to the calibration parameters , the calibration parameters are calculated as follows :

[0067]

[0068] in, is the measured value of the formic acid tank from 0 mbar to the maximum pressure; The measured value of the formic acid tank pressure from 0 mbar to the maintenance pressure; is the real-time pressure of the formic acid tank; is the deviation of the formic acid proportional valve.

[0069] As an example, the measured value of the formic acid tank from 0mbar to the maximum pressure The measured value of the formic acid tank from 0mbar to the maintenance pressure is 52.63. The deviation of the formic acid proportional valve is 31.53. The deviation of the acid proportional valve is 1.85. The deviation of the acid proportional valve here is only an example. In actual application, the deviation will vary depending on the different valve bodies of the formic acid proportional valve.

[0070] As a possible implementation, according to the calibration parameters Optimize backup pressure parameters , the optimization method is as follows:

[0071] when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is slow at first and then fast. At this time, the opening of the formic acid proportional valve is controlled to be large at first and then small.

[0072] when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is first fast and then slow. At this time, the opening of the formic acid proportional valve is controlled to be small first and then large.

[0073] when When the formic acid is filled into the formic acid tank, the flow rate is constant. At this time, the opening of the formic acid proportional valve is kept unchanged.

[0074] As an example, if we calculate The value is the calibration parameter and measured The value is the backup pressure parameter If inconsistent, calculate The value is the calibration parameter To optimize the backup pressure parameters Then test and verify until the backup pressure parameters are and calibration parameters Consistent, using the optimized backup pressure parameters after calibration To calculate the opening of the formic acid proportional valve .

[0075] S13. Calculation ,Right now ,in, Set flow rate for the vacuum chamber.

[0076] See also Figure 2 In practical applications, the maximum opening of the formic acid proportional valve is usually set to 100. In one possible case, if the calculated If it is greater than 100, it means that the calculation is wrong. In this case, S13 needs to be executed again to calculate the opening of the formic acid proportional valve.

[0077] The present invention does not require a flow meter, but only requires a formic acid proportional valve, and the formic acid flow rate can be accurately controlled by adjusting the opening of the formic acid proportional valve.

[0078] The following volume The experiment was conducted for a 40L vacuum chamber, and the formic acid flow rate of the vacuum chamber was set to 40L per minute. The pressure curve obtained by the actual measurement can be found in Figure 3 ,Depend on Figure 3 As can be seen from the figure, the time is 60 seconds, at which time the opening of the formic acid proportional valve is 33%, which meets the set flow requirement of 40L / min. Next, the formic acid flow rate of the vacuum chamber is set to 60L / min. The pressure curve obtained by the actual measurement is shown in Figure 2. Figure 4 ,Depend on Figure 4 As can be seen from the figure, the formic acid proportional valve is 50% open after 40 seconds, meeting the set flow rate requirement of 60 L / min. Tests were then conducted with the formic acid flow rates set to 10 L / min, 15 L / min, 125 L / min, and 130 L / min. The results all met the set requirements, demonstrating that the present invention can achieve precise control of formic acid flow. In practice, the opening of the formic acid proportional valve can be controlled by the PLC output current.

[0079] In a second aspect, the present invention provides an online vacuum welding furnace, in which no flow meter is provided on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the flow control method of the formic acid proportional valve provided in the first aspect is used to control the formic acid flow.

[0080] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may implement several functions listed in the claims. The fact that certain measures are recorded in mutually different dependent claims does not mean that these measures cannot be combined to produce good results.

[0081] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations may be made to the present invention by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A flow control method for a formic acid proportional valve, characterized in that: No flow meter is set on the pipeline between the formic acid tank and the vacuum chamber. Only a formic acid proportional valve is set to adjust the opening of the formic acid proportional valve in real time. The flow rate of formic acid flowing into the vacuum chamber is controlled to be constant; the flow rate control method comprises the following steps: S10. Calculate the average pressure difference of the vacuum chamber ; S11. Calculate the real-time pressure difference of the vacuum chamber ; S12. Calculate the slope of the formic acid tank pressure vs. filling time curve, which is the standby pressure parameter. Specifically, the formic acid tank pressure is inversely proportional to the vacuum chamber filling time, that is, the greater the formic acid tank pressure, the shorter the filling time; S13. Calculate the opening of the formic acid proportional valve ,Right now ,in, Set flow rate for the vacuum chamber.

2. The flow control method of a formic acid proportional valve according to claim 1, characterized in that: The S10 includes the following sub-steps: S100. Read the initial pressure of the vacuum chamber using the vacuum gauge ; S101. Configure the stop pressure of the vacuum chamber ; S102. Configure the set flow rate of the vacuum chamber ; S103. Calculate the average pressure difference in the vacuum chamber ,in, is the volume of the vacuum chamber.

3. The flow control method of a formic acid proportional valve according to claim 2, characterized in that: The S11 includes the following sub-steps: S110. Read real-time pressure value through vacuum gauge and remaining time ,time left From the initial pressure To stop pressure time difference; S111. Calculate the real-time pressure difference of the vacuum chamber .

4. The flow control method of a formic acid proportional valve according to claim 1, characterized in that: Apply calibration parameters Real-time calibration of standby pressure parameters , so that the backup pressure parameters at each moment Infinitely close to the calibration parameters , the calibration parameters are calculated as follows : in, is the measured value of the formic acid tank from 0 mbar to the maximum pressure; The measured value of the formic acid tank pressure from 0 mbar to the maintenance pressure; is the real-time pressure of the formic acid tank; is the deviation of the formic acid proportional valve.

5. The flow control method of a formic acid proportional valve according to claim 4, characterized in that: According to the calibration parameters Optimize backup pressure parameters , the optimization method is as follows: when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is slow at first and then fast. At this time, the opening of the formic acid proportional valve is controlled to be large at first and then small. when When the formic acid is filled into the formic acid tank, the flow rate of formic acid is first fast and then slow. At this time, the opening of the formic acid proportional valve is controlled to be small first and then large. when When the formic acid is filled into the formic acid tank, the flow rate is constant. At this time, the opening of the formic acid proportional valve is kept unchanged.

6. The flow control method of a formic acid proportional valve according to claim 1, characterized in that: The electrical parameters of the formic acid proportional valve are: operating voltage: 12-24V DC, voltage tolerance: ±10%, residual ripple: <5%, power consumption: 1W, output current: Max. 2A, input signal: 0-20mA, 4-20mA or 0-5V, 0-10V, input impedance for current input: <200Ω, input impedance for voltage input: >20kΩ, output signal: PWM signal, frequency range 80Hz-6kHz.

7. The flow control method of a formic acid proportional valve according to claim 6, characterized in that: The ambient temperature of the formic acid proportional valve is -10℃ to 60℃.

8. The flow control method of a formic acid proportional valve according to claim 7, characterized in that: The functional parameters of the formic acid proportional valve include the rise time function, which is adjustable from 0 to 10 seconds; The formic acid proportional valve is installed in the form of a cable plug, which is used for direct valve installation. The protection level of the formic acid proportional valve is IP65; the DIN rail installation type is IP40. The valve body material of formic acid proportional valve is: cable plug type is polyamide or PC; DIN rail mounting type is polyamide or PBT.

9. The flow control method of a formic acid proportional valve according to claim 1, characterized in that: The pressure in the formic acid tank is always maintained at 0.8~1.2Mpa.

10. An online vacuum welding furnace, characterized in that: No flow meter is provided on the pipeline between the formic acid tank and the vacuum chamber, only a formic acid proportional valve is provided, and the formic acid flow is controlled by the flow control method of the formic acid proportional valve according to any one of claims 1 to 9.

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