Hybrid Gas Rapid Inflation Device and Method with Flow Control

Abstract

The present invention describes a rapid inflation device and method for a mixed gas with flow control, including a first gas path and a second gas path. The first gas path is sequentially connected in series with a first gas tank, a first pressure reducing valve, a first heat exchanger, a first temperature control module, and a flow control branch and a proportional control branch in parallel downstream of the first temperature control module; the second gas path includes a second gas tank, a second pressure reducing valve, a second heat exchanger, and a second temperature control module connected in series in sequence; a flow control branch and a proportional control branch are connected in parallel downstream of the second temperature control module. During inflation, first close the two flow control branches, open the two proportional control branches, calculate the gas flow through the temperature, and control the mixing ratio of the directly filled mixed gas in the pipeline more precisely according to the opening degree of the flow control proportional valve, and be able to measure the gas volume according to the flow monitoring result; according to the mixing ratio detection result, close the proportional control branch and open the flow control branch to accurately compensate the mixing ratio of the mixed gas.

Description

Technical Field

[0001] The present invention relates to the technical field of gas insulation materials for inflatable equipment, and in particular to a rapid inflating device and method for mixed gas with flow control. Background Art

[0002] Since the 1960s and 1970s, sulfur hexafluoride (SF6) gas has been widely used as an insulating medium in inflatable equipment due to its excellent insulation and arc extinguishing properties. However, as a strong greenhouse gas, the global warming potential (GWP) of SF6 is 23,900 times that of CO2, and it can exist in the atmosphere for more than 3,200 years. Therefore, in the context of the "dual carbon" era, it is an inevitable trend to reduce the use of SF6 gas. At present, the State Grid is vigorously promoting the gas mixture reform and has achieved good application results, such as using SF6 / N2 and C4F7N / CO2 mixed insulating gases to replace pure SF6 gas. However, the operation and maintenance methods and devices related to the mixed insulating gas are not yet perfect and need further research.

[0003] The charging and supplementary charging of the mixed insulating gas are important links in the application of the mixed gas insulated equipment. The mixed gas insulated equipment has a rated gas mixture ratio, and improper charging and supplementary charging methods will cause deviation of the gas mixture ratio. For the SF6 / N2 mixed insulating gas, if the proportion of SF6 gas in the equipment is too small, it will affect the electrical insulation level and endanger the safety of the equipment power grid; conversely, if the proportion of SF6 gas is too large, it will violate the original intention of reducing the use of SF6 and affect the detection and management of the equipment. For the C4F7N / CO2 mixed insulating gas, C4F7N plays a major role in the insulation and arc extinguishing characteristics of the mixed insulating gas, but it is easy to liquefy itself, so its proportion also needs to be controlled within a reasonable range.

[0004] At present, the methods for charging and supplementary charging of the mixed gas are the partial pressure method and the dynamic gas distribution method. The partial pressure method is to first charge a certain partial pressure of gas according to the partial pressure, and then charge another part of the gas with a certain partial pressure. This method is simple to operate and has a fast inflation speed, but the gas mixture accuracy is relatively low, it is impossible to accurately measure the proportion of the charged gas, and the charged gas needs to be naturally diffused for a long time to be completely mixed, and the insulation and arc extinguishing performance may not meet the standards during this period. The dynamic gas distribution uses a high-precision mass flow controller (MFC) to strictly control the mass flow of each component gas and mix them according to the required gas mixture ratio. The gas distribution accuracy is high and the mixing effect is good. The dynamic gas distribution method can continuously and quickly configure mixed gases with different component contents, but limited by the range of the MFC, the gas flow rate will be reduced and the inflation speed is low.

[0005] For example, publication number CN108119749A discloses an SF6 and N2 mixed gas inflation device and precise inflation method. The device includes an SF6 inflation circuit, an N2 inflation circuit, a gas composition monitoring and feedback control device, and pressurized inflation. Based on the mass flow of the SF6 and N2 gases, the device precisely controls the composition of the two gases in the mixed gas. The device also features adaptive control capabilities, capable of detecting the SF6 and N2 gas composition in the GIS inflation device and automatically controlling the SF6 and N2 gas volumes. The device uses an MFC to control the outflow of SF6 / N2 gas, reducing the flow rate and extending the inflation time. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to solve the problem that the existing air filling and replenishing device has a slow filling speed and a long time.

[0007] The present invention solves the above technical problems through the following technical means:

[0008] A mixed gas rapid inflation device with flow control, comprising a first gas path, a second gas path, a buffer tank, a detection module, a compressor, and a vacuum pump;

[0009] The first gas circuit is connected in series with a first gas tank, a first pressure reducing valve, a first heat exchanger, a first temperature control module, a parallel flow control branch downstream of the first temperature control module, and a proportional control branch; the flow control branch includes a first solenoid valve and a first mass flow controller connected in series; the proportional control branch includes a second solenoid valve and a first proportional valve connected in series;

[0010] The second gas circuit includes a second gas tank, a second pressure reducing valve, a second heat exchanger, and a second temperature control module connected in series; a flow control branch and a proportional control branch are connected in parallel downstream of the second temperature control module; the flow control branch includes a third solenoid valve and a second mass flow controller connected in series; the proportional control branch includes a fourth solenoid valve and a second proportional valve connected in series;

[0011] After the first gas path and the second gas path are combined, they are connected in series in sequence to a buffer tank, a compressor, a fifth solenoid valve, and a pressure sensor;

[0012] In the present invention, pipeline direct charging (closing the flow control branch and opening the proportional control branch) is adopted. By detecting the temperature change of the gas passing through the temperature control module in the pipeline, the gas flow rate is calculated, and the opening degree of the proportional valve in the pipeline is controlled according to the flow feedback result, so as to more accurately control the mixing ratio of the mixed gas directly charged into the pipeline, and the gas volume can be measured according to the flow monitoring result; according to the mixing ratio detection result, the proportional control branch is closed and the flow control branch is opened, and the MFCs (the first mass flow controller and the second mass flow controller) in the flow control branch accurately compensate the mixing ratio of the mixed gas according to the mixed gas makeup algorithm to ensure that the mixing ratio of the final mixed gas charged into the gas chamber meets the requirements.

[0013] Furthermore, a vacuum pump is further included, and the downstream of the first temperature control module and the second temperature control module are both connected to the vacuum pump through a seventh solenoid valve and an eighth solenoid valve.

[0014] Furthermore, a mixing ratio detection module, a third proportional valve, and a sixth solenoid valve are sequentially connected in series between the upstream of the compressor and the upstream of the pressure sensor.

[0015] Furthermore, the upstream of the buffer tank is also connected to the vacuum pump through a ninth solenoid valve.

[0016] Matched with the above device, the present invention also provides a rapid inflation method for mixed gas with flow control, including the following steps:

[0017] (1) Start the vacuum pumping process;

[0018] (2) Open two gas cylinders, adjust the first pressure reducing valve and the second pressure reducing valve so that the pressure of the depressurized gas is 0.6 MPa, open the second, fourth, and fifth solenoid valves, and close the rest of the solenoid valves to enter the pipeline direct charging process;

[0019] The two-way gas respectively flows through the first heat exchanger and the second heat exchanger to initially heat up the SF6 gas in the gas cylinder, and then the two-way gas respectively enters the first temperature control module and the second temperature control module, and passes through the buffer tank along the two proportional control branches and is pressurized and filled into the inflation equipment by the compressor;

[0020] (3) Flow calculation: The first temperature control module includes the first, second, and third temperature sensors, as well as the first heating component and the second heating component; among them, the temperature T of the first heating component k1 is constantly T c +5 °C, the temperature T of the second heating component k2 is constantly T c +10 °C, and T c is the ambient temperature; the temperatures of the SF6 gas detected by the first, second, and third temperature sensors are T1, T2, and T3 respectively. The gas flow rate is calculated from this set of temperature data, and the calculation method is:

[0021] It can be known from the heat calculation formula that:

[0022] (1)

[0023] Where Q is the gas flow rate, G is the heat exchange amount generated, and k is the specific heat capacity of the gas. Therefore, the flow rate calculation formulas for SF6 and N2 are respectively:

[0024] (2)

[0025] Therefore, when the heat exchange amount is known, two sets of temperature differences can be obtained respectively according to T1, T2, and T3: (3)

[0026] (4)

[0027] Two sets of temperature differences can be used to calculate two flow rate values QSF6,1 and QSF6,2, and taking their average can improve the accuracy of flow rate calculation:

[0028] (5)

[0029] Similarly, calculate ;

[0030] (4) Flow control and measurement: Given the target mixing ratio of a%:b% (a% + b% = 1), according to the calculated flow rates of the two paths and , control the inner diameter opening of the first proportional valve or the second proportional valve 14, so as to achieve flow regulation,

[0031] Gas volume measurement: The output time of the two gas paths is the same, both set to t1, then the gas volumes m SF6,1 and m N2,1 of the two pipeline direct charging processes and the total gas volume m1 are:

[0032] According to the ideal gas state equation It can be obtained that:

[0033] (12)

[0034] (13)

[0035] (14)

[0036] In the formula, since the first temperature control module and the second temperature control module are close to the pressure reducing valve, and are both 0.6 MPa; M SF6 is the relative molecular mass of SF6, MN2 is the relative molecular mass of N2, R is a constant, T SF6 and T N2 is the Kelvin temperature of the gas in the pipeline, with the unit K;

[0037] (5) Calculate the mixing ratio of the supplementary mixed gas of the MFC: When the pressure sensor monitors that the pressure of the inflation device is the set pressure, close the second solenoid valve and the fourth solenoid valve, and the compressor continues to work for 1 minute to extract the gas in the buffer tank as much as possible to ensure that the gas pressure in the buffer tank is lower than the pressure in the inflation device; Open the sixth solenoid valve, and the gas in the inflation device flows through the third proportional valve and the mixing ratio detection module to the buffer tank under the action of the pressure difference, and record the mixing ratio of the inflation device as , and calculate the mixing ratio of the gas to be supplemented subsequently according to the following formula:

[0038] C SF6,s = (15)

[0039] In the above formula, C SF6,s ——The mixing ratio of the mixed gas to be supplemented; ——The target mixing ratio of the mixed gas in the inflation device; ——The value of the gas mixing ratio in the inflation device measured by the detection module before gas replenishment; The rated value of the pressure of the mixed gas in the inflation device; ——The measured value of the pressure of the mixed gas in the inflation device before gas replenishment; 0 ≤ ≤ 100%: Fill the inflation device with the mixed gas with a mixing ratio of to the rated pressure; When <0 or >100%, it means that the mixing ratio in the device cannot be adjusted to the rated value through a single gas replenishment. When >100%, the control terminal gives an N2 overcharge alarm; When <0, the control terminal gives an SF6 overcharge alarm;

[0040] Therefore, the mixing ratio of the mixed gas to be supplemented is C SF6,s : C N2,s , where C N2,s = 1 - C SF6,s .

[0041] (6) Close the sixth solenoid valve, open the first solenoid valve, the second solenoid valve and the fifth solenoid valve, and set the first MFC flow rate Q MFC,1 of the SF6 gas in the flow control branch to 150 L / min, and calculate the second MFC flow rate Q MFC,2 of the N2 gas in the flow control branch according to the mixing ratio of the mixed gas to be supplemented as (Q MFC,1 × CN2,s ) / C SF6,s L / min; When the pressure sensor detects that the pressure of the inflation device reaches the rated pressure, stop inflating, close all solenoid valves and MFC, and the inflation process ends;

[0042] (7) Calculate the m during the charging and gas replenishment process SF6 and m N2 and the total gas volume m are:

[0043] The gas volume during the MFC gas replenishment process is:

[0044] (16)

[0045] (17)

[0046] Therefore, the SF6, N2, and total gas volume charged during the whole process are:

[0047] (18)

[0048] (19)

[0049] (20)

[0050] (8) If the mixed gas charged is C4F7N / CO2, still follow steps (1) to (7). C4F7N is the same as SF6, and CO2 is the same as N2.

[0051] Further, the vacuum pumping process in step (1) is specifically as follows: Open all solenoid valves except the fifth and sixth solenoid valves, evacuate the entire pipeline to 133 Pa, let it stand for 30 min and read the vacuum value A, then let it stand for 5 h and read the vacuum value B. The rise value (B - A) should not exceed 67 Pa. After the vacuum pumping ends, close all solenoid valves and the vacuum pump.

[0052] Further, the specific adjustment method of the flow control in step (4) is:

[0053] If the two-way flow rates and currently detected satisfy: , it indicates that Q SF6 is too large, and it is necessary to reduce the SF6 gas flow rate and control the first proportional valve to reduce the inner diameter opening;

[0054] If , the opening degrees of the first proportional valve and the second proportional valve remain unchanged;

[0055] If ( , it indicates that Q N2If the N2 gas flow rate is too large, the second proportional valve should be controlled to reduce the inner aperture opening. Stop regulation and keep the opening of the second proportional valve unchanged.

[0056] The advantages of the present invention are:

[0057] During inflation, the present invention first uses direct pipeline filling (closing two flow control branches and opening two proportional control branches). By detecting the temperature change of the gas in the pipeline as it passes through the temperature control module, the gas flow rate is calculated. Based on the flow feedback, the opening of the proportional valve in the pipeline is controlled, allowing for relatively precise control of the mixing ratio of the mixed gas directly charged through the pipeline and metering of the gas volume based on the flow monitoring results. Based on the mixture ratio detection results, the proportional control branch is closed and the flow control branch is opened. The MFC in the flow control branch accurately compensates for the mixed gas mixture ratio according to the mixed gas replenishment algorithm, ensuring that the mixed gas mixture ultimately meets the required ratio when charged into the gas chamber. This method, which employs direct pipeline filling followed by precise MFC replenishment, balances inflation speed while ensuring the required mixed gas ratio is met, resulting in excellent mixing. The present invention detects and controls the flow rates of the two gas paths based on the temperature difference of the gas passing through the temperature control module, resulting in a highly accurate mixed gas ratio and the ability to directly meter the gas volume charged. The system also has the capability to charge SF6 / N2 and C4F7N / CO2 mixtures of varying ratios. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A schematic structural diagram of a device according to an embodiment of the present invention;

[0059] Figure 2 Schematic diagram of the structure of two temperature control modules in an embodiment of the present invention. DETAILED DESCRIPTION

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0061] like Figure 1 As shown, this embodiment records a mixed gas rapid inflation device with flow control, including a first gas path, a second gas path, a buffer tank 17, a detection module 20, a compressor 18, and a vacuum pump 26;

[0062] The first gas path is connected in series with a first gas tank 1, a first pressure reducing valve 3, a first heat exchanger 5, a first temperature control module 7, and a flow control branch and a proportional control branch in parallel downstream of the first temperature control module 7. The flow control branch includes a first solenoid valve 9 and a first mass flow controller 10 connected in series in sequence. The proportional control branch includes a second solenoid valve 11 and a first proportional valve 12 connected in series in sequence.

[0063] The second gas path includes a second gas tank 2, a second pressure reducing valve 4, a second heat exchanger 6, and a second temperature control module 8 connected in series in sequence. A flow control branch and a proportional control branch are connected in parallel downstream of the second temperature control module 8. The flow control branch includes a third solenoid valve 13 and a second mass flow controller 14 connected in series in sequence. The proportional control branch includes a fourth solenoid valve 15 and a second proportional valve 16 connected in series in sequence.

[0064] After the first gas path and the second gas path are combined, they are connected in series with a buffer tank 17, a compressor 18, a fifth solenoid valve 19, and a pressure sensor 23 in sequence.

[0065] Downstream of the first temperature control module 7 and the second temperature control module 8, they are both connected to a vacuum pump 26 through a seventh solenoid valve 24 and an eighth solenoid valve 25.

[0066] Between the upstream of the compressor 18 and the upstream of the pressure sensor 23, a mixing ratio detection module 20, a third proportional valve 21, and a sixth solenoid valve 22 are also connected in series in sequence.

[0067] Upstream of the buffer tank 17 is also connected to the vacuum pump 26 through a ninth solenoid valve 29.

[0068] In this embodiment, the first gas is SF6, and the corresponding second gas is N2, or the first gas is C4F7N, and the corresponding second gas is CO2.

[0069] In this embodiment, the first temperature control module 7 and the second temperature control module 8 are used to heat the gases in the first gas path and the second gas path, measure the temperature change of the gases before and after heating in the pipeline, indirectly obtain the gas flow rate, and can adjust the opening degrees of the first proportional valve 12 and the second proportional valve 16 according to the temperature measurement feedback result, so as to realize the regulation of the gas flow rate during direct filling of the pipeline; after the direct filling of the pipeline is set, the two proportional control branches are closed and the two flow control branches are used to accurately output the two component gases to the rated pressure. The specific method is as follows:

[0070] (1) Start the vacuum pumping process; open all solenoid valves except the fifth and sixth solenoid valves, evacuate the entire pipeline to 133 Pa, let it stand for 30 min and read the vacuum value A, then let it stand for 5 h and read the vacuum value B. The rise value (B - A) should not exceed 67 Pa. After the vacuum pumping is completed, close all solenoid valves and the vacuum pump 26;

[0071] (2) Open two gas cylinders, adjust the first pressure reducing valve 3 and the second pressure reducing valve 4 to make the pressure of the depressurized gas 0.6 MPa. Open the second, fourth, and fifth solenoid valves, and close the rest of the solenoid valves to enter the pipeline direct filling process;

[0072] The two-way gas flows through the first heat exchanger 5 and the second heat exchanger 6 respectively, initially heating the SF6 gas in the gas cylinder. Then the two-way gas enters the first and second temperature control modules respectively, and flows through the buffer tank 17 along the gas path and is pressurized and filled into the filling equipment by the compressor 18;

[0073] (3)Flow calculation: The first and second temperature control modules are as Figure 2 shown. The first temperature control module includes the first, second, and third temperature sensors, corresponding to Figure 2 the measurements of T1, T2, and T3 in it; and the first heating component and the second heating component; among which the temperature T of the first heating component k1 is constantly T c +5 °C, the temperature T of the second heating component k2 is constantly T c +10 °C, and T c is the ambient temperature; the temperatures of the SF6 gas detected by the first, second, and third temperature sensors are T1, T2, and T3 respectively. The gas flow rate is calculated from this set of temperature data, and the calculation method is:

[0074] It can be known from the heat calculation formula that:

[0075] (1)

[0076] where Q is the gas flow rate, G is the generated heat exchange amount, and k is the specific heat capacity of the gas. Therefore, the flow rate calculation formulas for SF6 and N2 are respectively:

[0077] (2)

[0078] Therefore, in the case of known heat exchange amount, two sets of temperature differences can be obtained according to T1, T2, and T3 respectively: (3)

[0079] (4)

[0080] The two sets of temperature differences can calculate two flow rate values QSF6,1 and QSF6,2, and averaging them can improve the accuracy of flow rate calculation:

[0081] (5)

[0082] Since the heat source in the selected heating component of the embodiment is a resistance wire with the same resistance value (resistance value is R), which is evenly wound on the surface of the pipeline, the pipeline materials are the same, the cross-sectional area of the pipeline is S, and the outside of the resistance wire is coated with heat insulation material, and the length of the wrapped part of the pipeline is L. For the heat generated on the resistance wire (the heat generated by the energization of the resistance wire), there are mainly three heat conduction paths, namely the heat Q0 of the resistance wire itself, the heat Qs dissipated to the outside through the heat insulation material, the heat Qk absorbed by the pipeline, and the heat absorbed by the gas in the pipeline, that is, the heat exchange amount G of the gas:

[0083] (6)

[0084] Since the resistance wire and the pipeline are made of metal materials, with a low specific heat capacity and being coated with heat insulation material, their heat can be ignored; the selected heat insulation material is an inorganic polymer thermal insulation material with excellent heat insulation effect, so the dissipated heat can also be ignored. Therefore, the above formula can be simplified as:

[0085] (7)

[0086] Among them The time when the gas flows through the pipeline wrapped by this heating component. According to the gas flow rate, flow velocity formula, and flow velocity, time formula:

[0087] (8)

[0088] (9)

[0089] Further calculation gives:

[0090] (10)

[0091] Substitute formula (10) into formula (2):

[0092] (11)

[0093] According to formula (11), calculate the flow rates Q SF6,1 and Q SF6,2 at the first and second heating components respectively, and find the average value . In the above formula, K SF6 is the specific heat capacity of SF6, and the value is 0.665 J / (g*K).

[0094] The calculation method of the other path of N2 also refers to this calculation method. The second temperature control module includes the fourth, fifth, and sixth temperature sensors, corresponding to Figure 2 the measurements of T4, T5, and T6 in k3 , as well as the third heating component and the fourth heating component; N2 is in gaseous storage. Similarly, the temperature T c of the third heating component is constant at T c+5°C, the temperature of the fourth heating component is T k4 Constant at T c +10°C; the SF6 gas temperatures detected by the fourth, fifth, and sixth temperature sensors are T4, T5, and T6 respectively. The calculated specific heat capacity of N2 is 1.038 J / (g*K).

[0095] (4)Flow control and metering: Given the target mixing ratio of a%:b% (a% + b% = 1), according to the calculated flow rates of the two paths and , control the inner diameter opening of the first proportional valve 12 or the second proportional valve 16 to achieve flow regulation

[0096] Gas volume metering: The output times of the two gas paths are the same, both set to t1. Then the gas volumes m SF6,1 and m N2,1 of the two pipeline direct charging processes and the total gas volume m1 are as follows:

[0097] According to the ideal gas state equation It can be obtained that:

[0098] (12)

[0099] (13)

[0100] (14)

[0101] In the formula, since the first temperature control module 7 and the second temperature control module 8 are close to the pressure reducing valve, and are both 0.6 MPa; M SF6 is the relative molecular mass of SF6, M N2 is the relative molecular mass of N2, R is a constant, T SF6 and T N2 are the Kelvin temperatures of the gas in the pipeline, in units of K;

[0102] (5)Calculate the mixing ratio of the MFC supplementary mixed gas: When the pressure sensor 23 detects that the pressure of the gas filling device is the set pressure (usually set to 90% of the rated pressure), close the second and fourth solenoid valves. The compressor 18 continues to work for a set duration, generally 1 minute, to pump out the gas in the buffer tank 17 as much as possible to ensure that the gas pressure in the buffer tank 17 is lower than the pressure in the gas filling device; open the sixth solenoid valve 22. The gas in the gas filling device flows through the third proportional valve 21 and the mixing ratio detection module 20 to the buffer tank 17 under the action of the pressure difference, and record the mixing ratio of the gas filling device as , and calculate the mixing ratio of the gas to be supplemented subsequently according to the following formula:

[0103] CSF6,s = (15)

[0104] In the above formula, C SF6,s —— Mixing ratio of the mixed gas to be supplemented; —— Target mixing ratio of the mixed gas in the gas filling device; —— Numerical value of the gas mixing ratio in the gas filling device measured by the pre-supplementary gas detection module 20; Rated value of the pressure of the mixed gas in the gas filling device; —— Measured value of the pressure of the mixed gas in the gas filling device before supplementary gas; 0 ≤ ≤ 100%: Fill the gas filling device with the mixed gas with a mixing ratio of to the rated pressure; When < 0 or > 100%, it means that the mixing ratio in the device cannot be adjusted to the rated value through a single supplementary gas. When > 100%, the control end gives an overcharge alarm for N2; When < 0, the control end gives an overcharge alarm for SF6;

[0105] Therefore, the mixing ratio of the mixed gas to be supplemented is C SF6,s : C N2,s , where C N2,s = 1 - C SF6,s .

[0106] (6) Close the sixth solenoid valve 22, open the first, second, and fifth solenoid valves 9, 11, 19, set the first MFC flow rate Q MFC,1 of the branch where the SF6 gas is located to 150 L / min, and calculate the second MFC flow rate Q MFC,2 of the branch where the N2 gas is located according to the mixing ratio of the mixed gas to be supplemented as (Q MFC,1 × C N2,s ) / C SF6,s L / min; Stop gas filling when the pressure sensor monitors that the pressure of the gas filling device reaches the rated pressure, close all solenoid valves and MFCs, and the gas filling process ends;

[0107] (7) Calculate the gas volumes m SF6 and m N2 during the gas supplementing and charging process and the total gas volume m as:

[0108] Gas volume during the MFC gas supplementing process is:

[0109] (16)

[0110] (17)

[0111] Therefore, the amount of SF6, N2 and total gas charged in the whole process is:

[0112] (18)

[0113] (19)

[0114] (20)

[0115] (8) If the mixed gas is C4F7N / CO2, then proceed according to steps (1) to (7). C4F7N is the same as SF6, and CO2 is the same as N2. The specific heat capacity of C4F7N is 0.835 J / (g*K); the specific heat capacity of CO2 is 0.840 J / (g*K).

[0116] During inflation, this embodiment first closes the two flow control branches and opens the two proportional control branches. By detecting the temperature change of the gas in the pipeline passing through the temperature control module, the gas flow rate is calculated. Based on the flow feedback, the opening of the proportional valve in the pipeline is controlled, thereby more accurately controlling the mixing ratio of the mixed gas directly charged into the pipeline and measuring the gas volume based on the flow monitoring results. Based on the mixture ratio detection results, the proportional control branch is closed and the flow control branch is opened. The MFC in the flow control branch accurately compensates for the mixed gas mixture ratio according to the mixed gas replenishment algorithm, ensuring that the mixed gas mixture ultimately meets the required mixing ratio when charged into the gas chamber. This embodiment employs direct pipeline filling followed by precise MFC replenishment, balancing inflation speed while ensuring that the mixed gas mixture meets the required mixing ratio and achieving a good mixing effect. This embodiment detects and controls the flow rates of the two gas paths based on the temperature difference of the gas passing through the temperature control module, resulting in a highly accurate mixed gas mixture ratio and the ability to directly measure the gas volume charged. The embodiment also has the capability to charge SF6 / N2 and C4F7N / CO2 mixtures of varying ratios.

[0117] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A rapid inflation device for mixed gas with flow control, characterized in that, It includes a first gas path, a second gas path, a buffer tank (17), a detection module (20), a compressor (18), and a vacuum pump (26); The first gas path is sequentially connected in series with a first gas tank (1), a first pressure reducing valve (3), a first heat exchanger (5), and a first temperature control module (7); downstream of the first temperature control module (7), a flow control branch and a proportional control branch are connected in parallel; the flow control branch includes a first solenoid valve (9) and a first mass flow controller (10) connected in series in sequence; the proportional control branch includes a second solenoid valve (11) and a first proportional valve (12) connected in series in sequence; The second gas path includes a second gas tank (2), a second pressure reducing valve (4), a second heat exchanger (6), and a second temperature control module (8) connected in series in sequence; downstream of the second temperature control module (8), a flow control branch and a proportional control branch are connected in parallel; the flow control branch includes a third solenoid valve (13) and a second mass flow controller (14) connected in series in sequence; the proportional control branch includes a fourth solenoid valve (15) and a second proportional valve (16) connected in series in sequence; After the first gas path and the second gas path are combined, they are sequentially connected in series with a buffer tank (17), a compressor (18), a fifth solenoid valve (19), and a pressure sensor (23); When the first gas is SF6, the corresponding second gas is N2, or when the first gas is C4F7N, the corresponding second gas is CO2; During gas filling, first close the two flow control branches, open the two proportional control branches, calculate the gas flow by detecting the temperature change of the gas passing through the temperature control module in the pipeline, and control the opening degree of the proportional valve in the pipeline according to the flow feedback result, so as to more accurately control the mixing ratio of the directly filled mixed gas in the pipeline, and be able to measure the gas volume according to the flow monitoring result; according to the mixing ratio detection result, close the proportional control branch, open the flow control branch, and the MFC in the flow control branch accurately compensates the mixing ratio of the mixed gas according to the mixed gas replenishment algorithm to ensure that the mixing ratio of the final mixed gas filled into the gas chamber meets the requirements.

2. The rapid inflation device for mixed gas with flow control according to claim 1, characterized in that It also includes a vacuum pump (26), and downstream of the first temperature control module (7) and the second temperature control module (8) are both connected to the vacuum pump (26) through a seventh solenoid valve (24) and an eighth solenoid valve (25).

3. The rapid inflation device for mixed gas with flow control according to claim 1 or 2, characterized in that, Between the upstream of the compressor (18) and the upstream of the pressure sensor (23), a mixing ratio detection module (20), a third proportional valve (21), and a sixth solenoid valve (22) are sequentially connected in series.

4. The rapid inflation device for mixed gas with flow control according to claim 2, wherein Upstream of the buffer tank (17) is also connected to the vacuum pump (26) through a ninth solenoid valve (29).

5. A method for rapid inflation of a mixed gas with flow control, applied to the device according to any one of claims 1 to 4, characterized in that, It includes the following steps: (1) Start the vacuum pumping process; (2) Open the two gas tanks, adjust the first pressure reducing valve (3) and the second pressure reducing valve (4) so that the pressure of the depressurized gas is 0.6 MPa, open the second, fourth, and fifth solenoid valves, and close the rest of the solenoid valves to enter the pipeline direct filling process; Two paths of gases flow through the first heat exchanger (5) and the second heat exchanger (6) respectively to preliminarily heat up the SF6 gas in the gas tank. Then the two paths of gases enter the first temperature control module (7) and the second temperature control module (8) respectively, and pass through the buffer tank (17) along the two proportional control branches, and are pressurized by the compressor (18) and filled into the filling equipment; (3)Flow calculation: The first temperature control module (7) includes the first, second, and third temperature sensors, as well as the first heating component and the second heating component; among them, the temperature T of the first heating component k1 is constantly T c +5 °C, and the temperature T of the second heating component k2 is constantly T c +10 °C, T c is the ambient temperature; the SF6 gas temperatures detected by the first, second, and third temperature sensors are T1, T2, and T3 respectively. The gas flow rate is calculated from this set of temperature data, and the calculation method is as follows: As can be seen from the heat calculation formula: （1） Where Q is the gas flow rate, G is the generated heat exchange amount, and k is the specific heat capacity of the gas. Therefore, the flow rate calculation formulas for SF6 and N2 are respectively: （2） Therefore, given the known heat transfer amount, two sets of temperature differences can be obtained based on T1, T2, and T3 respectively: (3) （4） Two temperature differences can be used to calculate two flow rate values QSF6,1 and QSF6,2, and averaging them can improve the accuracy of flow rate calculation: （5） Similarly, calculate ; (4) Flow control and metering: Given that the target mixing ratio is a%:b% (a% + b% = 1), according to the calculated flow rates of the two paths and , control the inner diameter opening of the first proportional valve (12) or the second proportional valve 14, so as to achieve flow regulation. Gas volume measurement: The output times of the two gas paths are the same, both set to t1, then the gas volumes m SF6,1 and m N2,1 as well as the total gas volume m1 are: According to the ideal gas state equation It can be obtained that: (12) (13) (14) Wherein, since the first temperature control module (7) and the second temperature control module (8) are close to the pressure reducing valve, and are both 0.6 MPa; M SF6 is the relative molecular mass of SF6, M N2 is the relative molecular mass of N2, R is a constant, T SF6 and T N2 are the Kelvin temperatures of the gas in the pipeline, with the unit K; (5) Calculate the mixing ratio of the MFC supplementary mixed gas: When the pressure sensor (23) monitors that the pressure of the inflation device is the set pressure, close the second solenoid valve (11) and the fourth solenoid valve (15), and the compressor (18) continues to work for 1 minute to pump out the gas in the buffer tank (17) as much as possible to ensure that the gas pressure in the buffer tank is lower than the pressure in the inflation device; open the sixth solenoid valve (22), and under the action of the pressure difference, the gas in the inflation device flows through the third proportional valve (21) and the mixing ratio detection module (20) to the buffer tank (17), and record the mixing ratio of the inflation device as , and calculate the mixing ratio of the gas to be supplemented subsequently according to the following formula: C SF6,s = (15) In the above formula, C SF6,s —— Mixing ratio of the mixed gas to be supplemented; —— Target mixing ratio of the mixed gas in the gas filling device; —— Value of the gas mixing ratio in the gas filling device measured by the pre-supplementary gas detection module (20); Rated value of the pressure of the mixed gas in the gas filling device; —— Measured value of the pressure of the mixed gas in the gas filling device before supplementary gas; 0 ≤ ≤ 100%: Fill the gas filling device with the mixed gas with a mixing ratio of to the rated pressure; When < 0 or > 100%, it indicates that the mixing ratio in the device cannot be adjusted to the rated value through a single supplementary gas. When > 100%, the control end gives an overcharge alarm for N2; When < 0, the control end gives an overcharge alarm for SF6; Therefore, the mixing ratio of the mixed gas to be supplemented is C SF6,s : C N2,s , where C N2,s = 1 - C SF6,s ; (6) Close the sixth solenoid valve (22), open the first solenoid valve (9), the second solenoid valve (11) and the fifth solenoid valve (19), and set the flow rate Q of the first mass flow controller (10) in the flow control branch where the SF6 gas is located MFC,1 to be 150 L / min, and calculate the flow rate Q of the second mass flow controller (14) in the flow control branch where the N2 gas is located according to the mixing ratio of the mixed gas to be supplemented MFC,2 to be (Q MFC,1 × C N2,s ) / C SF6,s L / min; When the pressure sensor (23) monitors that the pressure of the gas filling device is the rated pressure, stop gas filling, close all solenoid valves and MFC, and the gas filling process ends; (7) Calculate the process of charging and purging gas m SF6 and m N2 and the total gas volume m is: The gas volume during the MFC air replenishment process is: (16) (17) Therefore, the total gas volume of SF6, N2 and the total gas filled in the whole process is: (18) (19) (20) (8) If the mixed gas filled is C4F7N / CO2, the steps (1) to (7) are still followed. C4F7N is the same as SF6, and CO2 is the same as N2.

6. The method for rapid inflation of a mixed gas with flow control according to claim 5, characterized in that, The specific process of evacuating in step (1) is as follows: Open all solenoid valves except the fifth solenoid valve (19) and the sixth solenoid valve (22). Evacuate the entire pipeline to 133 Pa, let it stand for 30 minutes and read the vacuum value A, then let it stand for 5 hours and read the vacuum value B. The rising value (B - A) should not exceed 67 Pa. After the evacuation is completed, close all solenoid valves and the vacuum pump (26).

7. The rapid inflation method of a mixed gas with flow control according to claim 5, characterized in that, The specific adjustment method of flow rate control in step (4) is: If the two-way flow rates currently detected and meet the condition that , it indicates that Q SF6 is too large. It is necessary to reduce the SF6 gas flow rate and control the first proportional valve (12) to decrease the opening of the inner diameter. When , stop the regulation and keep the opening of the first proportional valve (12) unchanged; If , the opening degrees of the first proportional valve (12) and the second proportional valve (16) remain unchanged; If ( , it indicates that Q N2 is too large. It is necessary to reduce the flow rate of N2 gas and control the second proportional valve (16) to reduce the opening of the inner diameter. When , stop the regulation and keep the opening of the second proportional valve (16) unchanged.

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