CN112556774A - Gradient inflatable SF based on weighing method6Method for measuring volume of gas chamber - Google Patents
Gradient inflatable SF based on weighing method6Method for measuring volume of gas chamber Download PDFInfo
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- CN112556774A CN112556774A CN202011359046.4A CN202011359046A CN112556774A CN 112556774 A CN112556774 A CN 112556774A CN 202011359046 A CN202011359046 A CN 202011359046A CN 112556774 A CN112556774 A CN 112556774A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F22/00—Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
- G01F22/02—Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for involving measurement of pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C13/00—Details of vessels or of the filling or discharging of vessels
- F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
- F17C13/023—Special adaptations of indicating, measuring, or monitoring equipment having the mass as the parameter
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C13/00—Details of vessels or of the filling or discharging of vessels
- F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
- F17C13/025—Special adaptations of indicating, measuring, or monitoring equipment having the pressure as the parameter
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
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- F17C13/00—Details of vessels or of the filling or discharging of vessels
- F17C13/02—Special adaptations of indicating, measuring, or monitoring equipment
- F17C13/026—Special adaptations of indicating, measuring, or monitoring equipment having the temperature as the parameter
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G17/00—Apparatus for or methods of weighing material of special form or property
- G01G17/04—Apparatus for or methods of weighing material of special form or property for weighing fluids, e.g. gases, pastes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K13/00—Thermometers specially adapted for specific purposes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
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- F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
- F17C2250/06—Controlling or regulating of parameters as output values
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
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- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
- F17C2250/00—Accessories; Control means; Indicating, measuring or monitoring of parameters
- F17C2250/06—Controlling or regulating of parameters as output values
- F17C2250/0605—Parameters
- F17C2250/0631—Temperature
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
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Abstract
Gradient inflatable SF based on weighing method6A method for measuring the volume of a gas chamber, belonging to the SF6The technical field of measuring equipment, and solves the problem of how to accurately measure the SF of electrical equipment6The gas quantity in the gas chamber is accurately measured; distributing multiple stage inflation threshold values according to the set value of the air chamber pressure, inflating the air chamber in stages and measuring data, calculating the volume and the internal original gas mass of the air chamber in each stage, and taking each stageThe measured average value of the data eliminates the problem of larger accidental errors caused by one-time measurement from the initial value to the set value when the air chamber is inflated due to the measurement accuracy limitation of the pressure sensor, and improves the accuracy of the calculation result; the real-time pressure of gas can be accurately measured, the inflation flow can be controlled when the set pressure value is approached, the pressure sensor can detect when the gas is stable, the detection data is more accurate, and the potential safety hazard caused by overhigh gas pressure due to too much inflation gas in the gas chamber can be avoided.
Description
Technical Field
The invention belongs to SF6The technical field of measuring equipment, and relates to a gradient inflatable SF based on a weighing method6A method for measuring the volume of a gas cell.
Background
Sulfur hexafluoride (SF)6) Gases have been widely used in high and medium voltage electrical equipment due to their excellent insulating and arc extinguishing properties. According to statistics, the sulfur hexafluoride (SF) is used every year in the world6) The gas yield is about 2 ten thousand tons, and about 80 percent of the gas is applied to the power industry. SF along with large-scale construction and commissioning of AC/DC extra-high voltage engineering6The amount of gas used is increasing. But SF6The greenhouse effect of the gas is CO223900 times higher, can exist in air for 3200 years, is one of six gases which the Kyoto protocol prohibits from discharging.
Sulfur hexafluoride electrical equipment in the power industry is large in quantity and large in partThe gas consumption and the equipment volume (the equipment contains various complex structures and is difficult to estimate by the shape) are not marked on the nameplate of the operating equipment, and the SF6The gas charge is unknown; SF marked by part of new commissioning equipment nameplate6The gas inflation amount is inaccurate, and the actual operating pressure is generally higher than the rated pressure value, so the accurate data of the gas consumption of the sulfur hexafluoride of the electrical equipment is difficult to master, the gas recovery rate can not be controlled during the overhaul and retirement of the equipment, and the recovery rate can not reach the standard.
In order to control and reduce the emission of sulfur hexafluoride gas, a work mode of 'scattered recovery, centralized treatment, unified detection and cyclic utilization' is formed, and the recovery, recharging and purification treatment of the sulfur hexafluoride gas on site are realized. In the prior art, the Chinese utility model patent with application number of 201821892226.7 and publication date of 2019, 6 and 7 days is' SF6Gas metering device, as shown in fig. 4, specifically includes weighing device 1, mass flow meter 2, self-sealing joint 3, connector 4, pressure regulating needle valve 5, first manometer 6, second manometer 7, heating device 8, gas steel bottle 9. The device can acquire data such as weight of the gas-filled steel cylinder, gas flow, temperature of the steel cylinder, equipment pressure before and after operation in real time, and realize SF6And (4) real-time monitoring and management of gas supplementing data of the electrical equipment and the usage amount of the gas steel cylinder. If the device is used for charging and supplementing air to the vacuumized air chamber, the SF in the air chamber after the air supplement is determined according to the weighing device6The amount of gas.
The prior art has the following defects:
(1) due to the measurement accuracy limitation of the pressure sensor, when the air chamber is inflated, if the air chamber is inflated from an initial value to a set value at one time, measurement is carried out once, the volume of the air chamber and the mass of initial gas in the air chamber are calculated, the measurement inevitably has large accidental errors, a real-time pressure value is difficult to accurately measure, and the accuracy of a calculation result is difficult to guarantee.
(2) In the dynamic process of filling gas into the measuring device, the gas is in a flowing state, the gas pressure is unbalanced, the pressure sensor is difficult to judge whether the current pressure reaches the target pressure, and the measuring error is easy to occur in the measuring process.
Therefore, how to accurately SF the electrical equipment based on the on-site production requirements6The accurate measurement of the gas quantity in the gas chamber becomes a difficult problem to be solved at present.
Disclosure of Invention
The technical problem to be solved by the invention is how to accurately control the SF of the electrical equipment6The amount of gas inside the chamber is accurately measured.
The invention solves the technical problems through the following technical scheme:
gradient inflatable SF based on weighing method6A method of measuring the volume of a gas cell comprising the steps of:
step one, carrying out vacuum-pumping operation on the interior of the inflation measurement device, and measuring SF after vacuum-pumping6The mass number m1 of the steel cylinder (7);
step two, detecting SF6Initial gas pressure and temperature values P inside the gas chamber0And T0Calculating to obtain SF before air inflation according to Beattie-Bridgman empirical formula6Gas density ρ in the gas cell0；
Step three, according to SF6The plenum pressure setpoint assigns multiple stage inflation thresholds using SF6The steel cylinder (7) is used for supplying SF6Inflating air chamber and monitoring SF in real time6Dynamic pressure in the gas chamber if SF is detected6When the dynamic pressure in the air chamber has the tendency of rising to the inflation threshold value at the stage, the inflation flow is controlled by the flow regulating valve (5) to ensure that SF6Slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage, and recording SF at the moment after the pressure is balanced6The gas pressure and temperature of the gas chamber are P2、T2And then SF6The mass number m2 of the steel cylinder (7);
step four, calculating SF according to the pressure and mass values detected in the step one to step three in the inflation process of the stage6The total mass m of the initial gas in the gas chamber;
step five, repeating the step one to the step four, and carrying out next-stage inflation until SF is achieved6Pressure of air chamberSetting value, recording the detection data of each stage, and calculating SF according to the detection data of each stage6The total mass of the initial gas in the gas chamber is averaged.
The method of the invention distributes a plurality of stage inflation threshold values according to the set value of the pressure of the air chamber, inflates the air chamber in stages and measures data, each stage respectively calculates the volume of the air chamber and the original gas mass in the air chamber, and then the average value of the data measured in each stage is taken, thereby eliminating the problem of larger accidental errors caused by one-time measurement from the initial value to the set value when the air chamber is inflated due to the measurement accuracy limitation of the pressure sensor, and improving the accuracy of the calculation result.
As a further improvement of the technical solution of the present invention, the inflation measurement device includes: inflation interface (1), first solenoid valve (2), pressure sensor (3), temperature sensor (4), flow control valve (5), relief pressure valve (6), SF6The device comprises a steel cylinder (7), a weighing device (9), a second electromagnetic valve (10), a third electromagnetic valve (11), a vacuum gauge (12), a vacuum pump (13) and an exhaust port (14); inflation interface (1), first solenoid valve (2), pressure sensor (3), temperature sensor (4), flow control valve (5), relief pressure valve (6), SF6The steel cylinders (7) are sequentially connected in series in a sealing manner; a gas path is hermetically connected between the first electromagnetic valve (2) and the flow regulating valve (5), and a second electromagnetic valve (10), a vacuum pump (13) and an exhaust port (14) are sequentially connected; the vacuum gauge (12) is hermetically connected between the second electromagnetic valve (10) and the vacuum pump (13) through a third electromagnetic valve (11); the weighing device (9) is arranged at SF6The lower part of the steel cylinder (7).
As a further improvement of the technical scheme of the invention, the interior of the inflation measurement device is vacuumized in the step one, and after vacuumization, SF is measured6The mass value m1 of the steel cylinder (7) is as follows: closing the first electromagnetic valve (2), the reducing valve (6), opening the second electromagnetic valve (10), the third electromagnetic valve (11) and the flow regulating valve (5), starting the vacuum pump (13) to vacuumize the internal pipeline of the device, detecting the internal vacuum degree of the device by a vacuum gauge (12), closing all the electromagnetic valves when the vacuum degree reaches a certain value, stopping the vacuum pump (15), recording the weighing at the moment, and stopping the vacuum pump (15)Mass value m1 detected by the device (9).
As a further improvement of the technical scheme of the invention, the detection of SF in the step two6Initial gas pressure and temperature values P inside the gas chamber0And T0The method specifically comprises the following steps: connecting the gas-filled interface (1) to SF6The air chamber is only opened with the first electromagnetic valve (2) and detects SF through the pressure sensor (3) and the temperature sensor (4)6The values of the pressure and temperature of the gas in the gas chamber are recorded as P0、T0。
As a further improvement of the technical scheme of the invention, the SF before air inflation is calculated according to the Beattie-Bridgman empirical formula in the step two6Gas density ρ in the gas cell0The method specifically comprises the following steps:
will P0、T0Substituting Beattie-Bridgman empirical formula to obtain:
P0＝(RT0B-A)ρ0 2+RT0ρ0 (1)
wherein, A is 73.882 × 10-5-5.132105×10-7ρ，B＝2.50695×10-3-2.12283×10-6ρ，R＝56.9502×10-5Rho is SF in standard state6Gas density of (g) ("p0Is SF before inflation6Density of gas in the gas cell, ρ, is derived from equation (1)0The numerical value of (c).
As a further improvement of the technical scheme of the invention, the inflation flow is controlled by the flow regulating valve (5) in the step three to ensure that SF6The process of slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage specifically comprises the following steps:
1) during the inflation process, the pressure sensor (3) monitors SF in real time6The dynamic pressure in the air chamber is judged whether the dynamic pressure is less than or equal to 10% of the inflation threshold value of the current stage from the inflation threshold value of the current stage, if not, the aperture of the flow regulating valve (5) is kept open by 100%, and the SF is processed6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 50% opened, reducing the inflation flow and avoiding over-inflation;
2) judging whether the dynamic pressure is less than or equal to the inflation threshold value at the stage5% of the inflation threshold value in the stage, if not, the aperture 50% of the flow regulating valve (5) is kept open, and SF is fed6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 25% opened, reducing the inflation flow and avoiding over-inflation;
3) judging whether the dynamic pressure is less than or equal to 2% of the inflation threshold value of the stage from the threshold value, if not, keeping the aperture of the flow regulating valve (5) to be 25% open, and switching to SF6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 10% opened, reducing the inflation flow and avoiding over-inflation; and (4) turning off the flow regulating valve (5) until the inflation threshold value of the stage is reached, and ending the inflation process of the stage.
As a further improvement of the technical scheme of the invention, after the inflation process at the stage is finished, the pressure sensor (3) and the temperature sensor (4) are waited for detecting SF6After the pressure and temperature values in the air chamber are stable, recording SF6Gas pressure and temperature value P in the gas chamber2、T2And at this time the weighing device (9) detects the mass value m2, closing the first solenoid valve (2).
As a further improvement of the technical scheme of the invention, the SF is calculated according to the pressure and mass values detected in the step I to the step III in the inflation process of the stage in the step IV6The total mass m of the initial gas in the gas chamber is as follows:
according to the empirical formula of Beattie-Bridgman, the values P detected by the pressure sensor (3) and the temperature sensor (4) after the inflation at the stage are2、T2Substituting to obtain:
P2＝(RT2 B-A)ρ2 2+RT2ρ2 (2)
where ρ is2For SF after inflation6The density of the gas within the gas chamber;
according to the density formula, since SF6The volume V of the air chamber is unchanged, namely the density formulas before and after inflation are subtracted:
Δm＝V×Δρ (3)
wherein Δ ρ is SF before and after inflation6Density of gas in gas chamberChange value, Δ ρ ═ ρ2-ρ0；
Then subtracting the mass values m1 and m2 detected by the weighing device (9) before and after inflation to obtain m1-m2Substituting Δ ρ and Δ m into formula (4) to obtain a chamber volume V:
SF6initial total gas mass m in the gas chamber:
wherein m is SF6Initial total mass of gas in the gas chamber.
As a further improvement of the technical scheme of the invention, the pressure reducing valve (6) is connected with the flow regulating valve (5) through a hose.
As a further improvement of the technical scheme of the invention, the inflation measuring device also comprises a fixing frame (8), and the fixing frame (8) is used for fixing SF6Steel cylinder (7)
The invention has the advantages that:
(1) the method of the invention distributes a plurality of stage inflation threshold values according to the set value of the pressure of the air chamber, inflates the air chamber in stages and measures data, each stage respectively calculates the volume of the air chamber and the original gas mass in the air chamber, and then the average value of the data measured in each stage is taken, thereby eliminating the problem of larger accidental errors caused by one-time measurement from the initial value to the set value when the air chamber is inflated due to the measurement accuracy limitation of the pressure sensor, and improving the accuracy of the calculation result.
(2) The method can accurately measure the real-time pressure of the gas, can control the inflation flow when the set pressure value is approached, enables the pressure sensor to detect when the gas is stable, has more accurate detection data, and can not cause potential safety hazards caused by overhigh gas pressure due to excessive inflation of the gas chamber.
(3) The pressure sensor (3) and the temperature sensor (4) are installed at the foremost end of the device, the first electromagnetic valve (2) is opened, gas in the gas chamber can be directly detected through the gas charging interface (1) to obtain accurate real-time pressure and temperature values, the density value of the gas chamber is calculated according to an empirical formula, and influences caused by temperature changes during detection are eliminated.
(4) The pressure reducing valve (6) is connected with the device through a hose, so that other components in the device do not apply stress to the SF6 steel cylinder (7) through the pressure reducing valve (6), namely, the detection result of the weighing device (7) is not influenced.
(5) The pressure reducing valve (6) is fixed on an SF6 steel cylinder (7); the fixed frame (8) is respectively fixed with the SF6 steel cylinder (7) and the weighing device (9), the fixed frame (8) fixes the position of the SF6 steel cylinder (7), and the fixed frame and the SF6 steel cylinder do not move relatively; fixed frame (8) are kept flat and are fixed on weighing device (9), not only make weighing device (9) can effectively detect out the mass numerical value of fixed frame (8), relief pressure valve (6) and SF6 steel bottle (7), can also guarantee that the device can not freely remove and cause the potential safety hazard in handling SF6 steel bottle (7).
Drawings
FIG. 1 is a block diagram of an inflation measurement device according to an embodiment of the present invention;
FIG. 2 is a flow chart of an assay method according to an embodiment of the present invention;
FIG. 3 is a flow chart of a gradient charging control algorithm for the determination method of an embodiment of the present invention;
FIG. 4 is a prior art SF6Gas metering device structure diagram.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The technical scheme of the invention is further described by combining the drawings and the specific embodiments in the specification:
example one
As shown in fig. 1, the inflation measurement apparatus includes: inflation interface 1, first solenoid valve 2, pressure sensor 3, temperature sensor 4, flow control valve 5, relief pressure valve 6, SF6The device comprises a steel cylinder 7, a fixed frame 8, a weighing device 9, a second electromagnetic valve 10, a third electromagnetic valve 11, a vacuum gauge 12, a vacuum pump 13 and an exhaust port 14; inflation interface 1, first solenoid valve 2, pressure sensor 3, temperature sensor 4, flow control valve 5, relief pressure valve 6, SF6The steel cylinders 7 are sequentially connected in series in a sealing manner; a gas path is hermetically connected between the first electromagnetic valve 2 and the flow regulating valve 5, and a second electromagnetic valve 10, a vacuum pump 13 and an exhaust port 14 are sequentially connected; the vacuum gauge 12 is hermetically connected between the second electromagnetic valve 10 and the vacuum pump 13 through a third electromagnetic valve 11; the fixing frame 8 is used for fixing SF6A steel cylinder 7; the weighing device 9 is arranged at SF6The lower part of the steel cylinder 7; the inflation interface 1 can realize self-sealing when not connected with the air chamber.
As shown in fig. 2, gradient gas filled SF based on weighing method6A method of measuring the volume of a gas cell comprising the steps of:
1. before the device is used, the internal pipeline of the device is vacuumized, and the value m1 of the weighing device 9 is recorded after the vacuumizing operation. Closing the first electromagnetic valve 2 and the pressure reducing valve 6, opening the second electromagnetic valve 10, the third electromagnetic valve 11 and the flow regulating valve 5, starting the vacuum pump 13 to vacuumize the internal pipeline of the device, detecting the internal vacuum degree of the device by the vacuum gauge 12, closing all the electromagnetic valves when the vacuum degree reaches a certain value, stopping the vacuum pump 15, and recording the mass value m1 detected by the weighing device 9 at the moment.
2. Detection of SF6Initial gas pressure and temperature values P inside the gas chamber0And T0Calculating to obtain SF before air inflation according to Beattie-Bridgman empirical formula6Gas density ρ in the gas cell0. Connecting the gas charging interface 1 into SF6A gas chamber for opening the first solenoid valve 2 and detecting SF by the pressure sensor 3 and the temperature sensor 46The values of the pressure and temperature of the gas in the gas chamber are recordedP0、T0(ii) a Will P0、T0Substituting Beattie-Bridgman empirical formula to obtain:
P0＝(RT0 B-A)ρ0 2+RT0ρ0 (1)
wherein, A is 73.882 × 10-5-5.132105×10-7ρ，B＝2.50695×10-3-2.12283×10-6ρ，R＝56.9502×10-5Rho is SF in standard state6Gas density of (g) ("p0Is SF before inflation6Density of gas in the gas cell, ρ, is derived from equation (1)0The numerical value of (c).
3. According to SF6The plenum pressure setpoint assigns multiple stage inflation thresholds using SF6Steel cylinder 7 for SF6Inflating air chamber and monitoring SF in real time6Dynamic pressure in the gas chamber if SF is detected6When the dynamic pressure in the air chamber has a tendency of rising to the inflation threshold value at this stage, the inflation flow is controlled by the flow regulating valve 5 to enable SF6Slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage, and recording SF at the moment after the pressure is balanced6The gas pressure and temperature of the gas chamber are P2、T2And the weighing means 9 now detects the mass value m 2.
Suppose SF6The gas chamber needs to be filled from 0.7MPa to 0.8MPa, then SF6The set value of the air chamber pressure is 0.8MPa, if the air is inflated in five stages (or not, and set as required), the inflation threshold value of each stage is 0.02MPa, and then the five stages are respectively: the first stage is filled from 0.7MPa to 0.72 MPa; in the second stage, the pressure is increased from 0.72MPa to 0.74 MPa; the third stage is filled from 0.74MPa to 0.76 MPa; the fourth stage is from 0.76MPa to 0.78 MPa; the fifth stage is filled from 0.78MPa to 0.8MPa (SF)6The air chamber pressure set point); and recording the detection data of the inflation at each stage.
As shown in FIG. 3, the flow rate of the inflation gas is controlled by the flow control valve 5 so that SF6The process of slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage specifically comprises the following steps:
1) during inflation, the pressure sensor 3 monitors SF in real time6The dynamic pressure in the air chamber is judged whether the dynamic pressure is less than or equal to 10% of the inflation threshold value of the current stage from the inflation threshold value of the current stage, if not, the aperture of the flow regulating valve 5 is kept to be 100% open, and the SF is processed6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve 5 to be 50% opened, reducing the inflation flow and avoiding over-inflation;
2) judging whether the dynamic pressure is less than or equal to 5% of the inflation threshold value of the current stage, if not, keeping the aperture of the flow regulating valve 5 to be 50% open, and switching to SF6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve 5 to be 25% opened, reducing the inflation flow and avoiding over-inflation;
3) judging whether the dynamic pressure is less than or equal to 2% of the inflation threshold value of the stage from the threshold value, if not, keeping the aperture of the flow regulating valve 5 to be 25%, and switching to SF6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve 5 to be 10% opened, reducing the inflation flow and avoiding over-inflation; and (4) turning off the flow regulating valve 5 until the inflation threshold of the stage is reached, and ending the inflation process of the stage.
After the inflation process at this stage is finished, the pressure sensor 3 and the temperature sensor 4 are waited for detecting SF6After the pressure and temperature values in the air chamber are stable, recording SF6Gas pressure and temperature value P in the gas chamber2、T2And at this time the weighing means 9 detects the mass value m2, the first solenoid valve 2 is closed.
4. Calculating SF according to the pressure and mass values detected in the step one to the step three in the inflation process of the stage6The total mass m of the initial gas in the gas chamber; according to the empirical formula of Beattie-Bridgman, the values P detected by the pressure sensor 3 and the temperature sensor 4 after being inflated at the stage are2、T2Substituting to obtain:
P2＝(RT2 B-A)ρ2 2+RT2ρ2 (2)
where ρ is2For SF after inflation6The density of the gas within the gas chamber;
according to the formula of density, sinceSF6The volume V of the air chamber is unchanged, namely the density formulas before and after inflation are subtracted:
Δm＝V×Δρ (3)
wherein Δ ρ is SF before and after inflation6Density change value of gas in gas chamber, Δ ρ ═ ρ2-ρ0；
Then subtracting the mass values m1 and m2 detected by the weighing device 9 before and after inflation to obtain m ═ m1-m2Substituting Δ ρ and Δ m into formula (4) to obtain a chamber volume V:
SF6initial total gas mass m in the gas chamber:
wherein m is SF6Initial total mass of gas in the gas chamber.
5. Repeating the steps 1 to 4, and carrying out next stage of inflation until SF is achieved6Setting the pressure of the air chamber, recording the detection data of each stage, and calculating SF according to the detection data of each stage6The total mass of the initial gas in the gas chamber is averaged.
The pressure sensor 3 and the temperature sensor 4 are arranged at the most front end of the device, the gas in the gas chamber can be directly detected through the gas charging interface 1 by opening the first electromagnetic valve 2 to obtain accurate real-time pressure and temperature values, and the density value of the gas chamber is calculated according to an empirical formula, so that the influence caused by temperature change in the detection period is eliminated. The pressure reducing valve 6 is fixed on SF6A steel cylinder 7; the fixed frame 8 is respectively connected with SF6The steel cylinder 7 and the weighing device 9 are fixed, and the fixing frame 8 fixes SF6The position of the steel cylinder 7 does not move relatively; the fixed frame 8 is flatly arranged and fixed on the weighing device 9, so that the weighing device 9 can effectively detect the fixed frame 8, the pressure reducing valve 6 and the SF6The quality value of the steel cylinder 7 can beEnsuring the SF of the device in the process of carrying6The steel cylinder 7 can not be moved randomly to cause potential safety hazard. The pressure reducing valve 6 is connected with the device through a hose, so that other parts in the device do not pass through the pressure reducing valve 6 to SF6The steel cylinder 7 is stressed, i.e. the detection result of the weighing device 7 is not influenced.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. Gradient inflatable SF based on weighing method6A method for measuring a volume of a gas cell, comprising the steps of:
step one, carrying out vacuum-pumping operation on the interior of the inflation measurement device, and measuring SF after vacuum-pumping6The mass number m1 of the steel cylinder (7);
step two, detecting SF6Initial gas pressure and temperature values P inside the gas chamber0And T0Calculating to obtain SF before air inflation according to Beattie-Bridgman empirical formula6Gas density ρ in the gas cell0；
Step three, according to SF6The plenum pressure setpoint assigns multiple stage inflation thresholds using SF6The steel cylinder (7) is used for supplying SF6Inflating air chamber and monitoring SF in real time6Dynamic pressure in the gas chamber if SF is detected6When the dynamic pressure in the air chamber has the tendency of rising to the inflation threshold value at the stage, the inflation flow is controlled by the flow regulating valve (5) to ensure that SF6Slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage, and recording SF at the moment after the pressure is balanced6The gas pressure and temperature of the gas chamber are P2、T2And then SF6The mass number m2 of the steel cylinder (7);
step four,Calculating SF according to the pressure and mass values detected in the step one to the step three in the inflation process of the stage6The total mass m of the initial gas in the gas chamber;
step five, repeating the step one to the step four, and carrying out next-stage inflation until SF is achieved6Setting the pressure of the air chamber, recording the detection data of each stage, and calculating SF according to the detection data of each stage6The total mass of the initial gas in the gas chamber is averaged.
2. Weighing-based gradient gas filled SF according to claim 16A method for measuring a volume of a gas chamber, said method comprising: inflation interface (1), first solenoid valve (2), pressure sensor (3), temperature sensor (4), flow control valve (5), relief pressure valve (6), SF6The device comprises a steel cylinder (7), a weighing device (9), a second electromagnetic valve (10), a third electromagnetic valve (11), a vacuum gauge (12), a vacuum pump (13) and an exhaust port (14); inflation interface (1), first solenoid valve (2), pressure sensor (3), temperature sensor (4), flow control valve (5), relief pressure valve (6), SF6The steel cylinders (7) are sequentially connected in series in a sealing manner; a gas path is hermetically connected between the first electromagnetic valve (2) and the flow regulating valve (5), and a second electromagnetic valve (10), a vacuum pump (13) and an exhaust port (14) are sequentially connected; the vacuum gauge (12) is hermetically connected between the second electromagnetic valve (10) and the vacuum pump (13) through a third electromagnetic valve (11); the weighing device (9) is arranged at SF6The lower part of the steel cylinder (7).
3. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of the air chamber is characterized in that the inside of the air inflation measuring device is vacuumized in the step one, and SF is measured after vacuumizing6The mass value m1 of the steel cylinder (7) is as follows: closing the first electromagnetic valve (2), the reducing valve (6), opening the second electromagnetic valve (10), the third electromagnetic valve (11) and the flow regulating valve (5), starting the vacuum pump (13) to vacuumize the internal pipeline of the device, detecting the internal vacuum degree of the device by a vacuum gauge (12), and closing all the electromagnetic valves when the vacuum degree reaches a certain valueAnd (4) stopping the vacuum pump (15) and recording the mass value m1 detected by the weighing device (9) at the moment.
4. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of a gas cell, characterized in that the detection SF in the step two6Initial gas pressure and temperature values P inside the gas chamber0And T0The method specifically comprises the following steps: connecting the gas-filled interface (1) to SF6The air chamber is only opened with the first electromagnetic valve (2) and detects SF through the pressure sensor (3) and the temperature sensor (4)6The values of the pressure and temperature of the gas in the gas chamber are recorded as P0、T0。
5. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of the air chamber is characterized in that the SF before air inflation is calculated according to the Beattie-Bridgman empirical formula in the step two6Gas density ρ in the gas cell0The method specifically comprises the following steps:
will P0、T0Substituting Beattie-Bridgman empirical formula to obtain:
P0＝(RT0B-A)ρ0 2+RT0ρ0 (1)
wherein, A is 73.882 × 10-5-5.132105×10-7ρ，B＝2.50695×10-3-2.12283×10-6ρ，R＝56.9502×10-5Rho is SF in standard state6Gas density of (g) ("p0Is SF before inflation6Density of gas in the gas cell, ρ, is derived from equation (1)0The numerical value of (c).
6. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of the air chamber is characterized in that the inflation flow is controlled by a flow regulating valve (5) in the third step so that SF6The process of slowly inflating the gas pressure in the gas chamber to the inflation threshold value at the stage specifically comprises the following steps:
1) during the inflation process, the pressure sensor (3) monitors SF in real time6The dynamic pressure in the air chamber is judged whether the dynamic pressure is less than or equal to 10% of the inflation threshold value of the current stage from the inflation threshold value of the current stage, if not, the aperture of the flow regulating valve (5) is kept open by 100%, and the SF is processed6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 50% opened, reducing the inflation flow and avoiding over-inflation;
2) judging whether the dynamic pressure is less than or equal to 5% of the inflation threshold value of the stage, if not, keeping the aperture of the flow regulating valve (5) open by 50%, and switching to SF6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 25% opened, reducing the inflation flow and avoiding over-inflation;
3) judging whether the dynamic pressure is less than or equal to 2% of the inflation threshold value of the stage from the threshold value, if not, keeping the aperture of the flow regulating valve (5) to be 25% open, and switching to SF6Inflating the air chamber; if yes, controlling the aperture of the flow regulating valve (5) to be 10% opened, reducing the inflation flow and avoiding over-inflation; and (4) turning off the flow regulating valve (5) until the inflation threshold value of the stage is reached, and ending the inflation process of the stage.
7. Gradient gas filled SF according to claim 6 based on weighing method6The method for measuring the volume of the air chamber is characterized in that after the inflation process at the stage is finished, the pressure sensor (3) and the temperature sensor (4) are waited for detecting SF6After the pressure and temperature values in the air chamber are stable, recording SF6Gas pressure and temperature value P in the gas chamber2、T2And at this time the weighing device (9) detects the mass value m2, closing the first solenoid valve (2).
8. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of the air chamber is characterized in that the SF is calculated according to the pressure and mass values detected in the first step to the third step in the step four during the inflation process6The total mass m of the initial gas in the gas chamber is as follows:
according to the empirical formula of Beattie-Bridgman, the pressure is adjustedThe force sensor (3) and the temperature sensor (4) detect the numerical value P after the inflation at the stage2、T2Substituting to obtain:
P2＝(RT2B-A)ρ2 2+RT2ρ2 (2)
where ρ is2For SF after inflation6The density of the gas within the gas chamber;
according to the density formula, since SF6The volume V of the air chamber is unchanged, namely the density formulas before and after inflation are subtracted:
Δm＝V×Δρ (3)
wherein Δ ρ is SF before and after inflation6Density change value of gas in gas chamber, Δ ρ ═ ρ2-ρ0；
Then subtracting the mass values m1 and m2 detected by the weighing device (9) before and after inflation to obtain m1-m2Substituting Δ ρ and Δ m into formula (4) to obtain a chamber volume V:
SF6initial total gas mass m in the gas chamber:
wherein m is SF6Initial total mass of gas in the gas chamber.
9. Gradient gas filled SF according to claim 2 based on weighing method6The method for measuring the volume of the air chamber is characterized in that the pressure reducing valve (6) is connected with the flow regulating valve (5) through a hose.
10. Gradient gas filled SF according to claim 2 based on weighing method6The method for determining the volume of a gas cell is characterized in that the inflation measuring device further comprises a fixing frame (8), and the fixing frame is fixed on the fixing frameThe fixed frame (8) is used for fixing SF6A steel cylinder (7).
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