Precision detection method of electric control flowmeter in anaesthesia machine

Abstract

The invention discloses a precision detection method for a laughing air electronic control flowmeter in an anaesthesia machine. The method comprises the following steps: connecting a gas flow detection device with a flow control system; carrying out precision calibration on the gas flow detection device; oxygen enters through the oxygen inlet and is introduced into the atmosphere, air enters through the laughing gas inlet, the air inlet is closed, and a first flow value recorded by the gas flow detection device is obtained; laughing conversion coefficients at different preset flow values are calculated respectively; determining a verification conversion coefficient; oxygen with a fixed flow value enters through the oxygen inlet and flows through the gas flow detection device, air enters through the laughing gas inlet, the air inlet is closed, and a second flow value displayed by the laughing gas and air electric control flowmeter is obtained; determining a verification flow value range; if the third flow value displayed by the gas flow detection device is within the verification flow value range, it is determined that the precision of the laughing air electric control flowmeter meets the standard. Air can be used for replacing laughing gas for testing.

Description

Technical Field

[0001] This application relates to the field of anesthesia machine technology, specifically to a method for detecting the accuracy of an electrically controlled flow meter in an anesthesia machine. Background Technology

[0002] Electrically controlled flow meters are used in anesthesia machines in hospital operating rooms and are one of the components of anesthesia machines. Driven by the working pressure of the gas source, they can precisely control the output of oxygen, air, and nitrous oxide gas as needed, providing fresh gas for the anesthesia vaporizer and circuit system in the anesthesia workstation.

[0003] Currently, the accuracy of nitrous oxide flow output of anesthesia machines equipped with electronic flow meters is tested using real nitrous oxide before leaving the factory. However, nitrous oxide is a hazardous chemical, and the testing process is highly dangerous when using it as the gas for testing the accuracy of electronic flow meters. In addition, some regions restrict companies from purchasing nitrous oxide, and the procurement cost of nitrous oxide is high. Summary of the Invention

[0004] The purpose of this application is to overcome the shortcomings of existing technologies and propose a method for detecting the accuracy of electrically controlled flow meters in anesthesia machines. This application significantly reduces gas procurement costs by using air instead of nitrous oxide for testing, avoids harm to employee health due to nitrous oxide inhalation during the testing process, and also prevents environmental pollution.

[0005] Specifically, this application provides a method for detecting the accuracy of an electrically controlled flow meter in an anesthesia machine. The nitrous oxide electrically controlled flow meter is installed in the first flow control branch of the flow control system in the anesthesia machine. The first flow control branch includes a nitrous oxide inlet and an air inlet. The method includes: Step 1: Connect the gas flow detection device to the flow control system; Step 2: Perform accuracy calibration on the gas flow detection device; Step 3: When calibration is complete, oxygen is introduced into the atmosphere through the oxygen inlet of the second flow control branch in the flow control system, and air is introduced through the nitrous oxide inlet. The air inlet is closed. When the nitrous oxide electronic flow meter displays a preset flow value, the first flow value recorded by the gas flow detection device is obtained. The preset flow value includes multiple values, and each preset value corresponds to a different first flow value. Step 4: Calculate the first conversion coefficient for different preset flow rates based on the ratio of the preset flow rate to the first flow rate corresponding to the preset flow rate; Step 5: Determine the verification conversion coefficients based on the multiple first conversion coefficients; Step 6: Allow oxygen of a fixed flow rate to enter through the oxygen inlet of the second flow control branch and flow through the gas flow detection device, allow air to enter through the nitrous oxide inlet, close the air inlet, and obtain the second flow rate value displayed by the nitrous oxide electronic flow meter. Step 7: Determine the range of verification flow values ​​based on the fixed flow value, the ratio of the second flow value to the verification conversion coefficient, and the preset accuracy error of the Xiaokong electronic flow meter; Step 8: If the third flow value displayed by the gas flow detection device is within the range of the verified flow value, then it is determined that the accuracy of the Xiaokong electronic flow meter meets the standard.

[0006] In some embodiments, step 2 specifically includes: Step 21: Close the nitrous oxide inlet and the air inlet, and allow oxygen to enter through the oxygen inlet at the first calibration flow rate value and flow through the gas flow detection device. When the flow rate value displayed by the gas flow detection device is different from the first calibration flow rate, calibrate the gas flow detection device. Step 22: Close the nitrous oxide inlet and the oxygen inlet, and allow air to enter through the air inlet at the second verification flow rate value and flow through the gas flow detection device. When the flow rate value displayed by the gas flow detection device is different from the second verification flow rate, calibrate the gas flow detection device. Step 23: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the third verification flow rate value, and flow through the gas flow detection device. Allow oxygen to enter through the oxygen inlet and flow into the atmosphere. If the flow rate value displayed by the gas flow detection device is different from the third verification flow rate, calibrate the gas flow detection device.

[0007] In some embodiments, step 2 may further include the following steps: Step 24: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the fourth verification flow rate value and flow through the gas flow detection device, allow oxygen to enter through the oxygen inlet at the fifth verification flow rate value and flow through the gas flow detection device, and when the flow rate value displayed by the gas flow detection device is different from the first mixed flow rate value, calibrate the gas flow detection device, wherein the first mixed flow rate value is determined based on the sum of the fourth verification flow rate and the fifth verification flow rate; Step 25: Close the nitrous oxide inlet, allow air to enter through the air inlet at the sixth calibration flow rate and flow through the gas flow detection device, allow oxygen to enter through the oxygen inlet at the seventh calibration flow rate and flow through the gas flow detection device, and when the flow rate value displayed by the gas flow detection device is different from the second mixed flow rate value, calibrate the gas flow detection device, wherein the second mixed flow rate value is determined based on the sum of the sixth calibration flow rate and the seventh calibration flow rate.

[0008] In some embodiments, step 5 specifically includes: Obtain the theoretical conversion coefficient; Step 5 specifically includes: Obtain the theoretical conversion coefficient; If the difference between the maximum and minimum values ​​among the plurality of first conversion coefficients does not exceed 0.03, and the minimum value among the plurality of first conversion coefficients is greater than the theoretical conversion coefficient of 0.03, then the average value of the plurality of first conversion coefficients is determined as the verification conversion coefficient; If the difference between the maximum and minimum values ​​among the plurality of first conversion coefficients does not exceed 0.03, and the maximum value of the plurality of first conversion coefficients is less than the theoretical conversion coefficient of 0.03, then the theoretical conversion coefficient is determined as the verification conversion coefficient; If the multiple first conversion coefficients are different, the magnitude of the multiple first conversion coefficients gradually increases or gradually decreases, and when gradually increasing, the minimum value among the multiple first conversion coefficients is greater than the theoretical conversion coefficient 0.03, or when gradually decreasing, the minimum value among the multiple first conversion coefficients is less than the theoretical conversion coefficient 0.03, then it is determined that each of the preset flow rates corresponds to a first conversion coefficient.

[0009] In some embodiments, step 6 specifically includes: Oxygen with a fixed flow rate is introduced through the oxygen inlet of the second flow control branch and flows through the gas flow detection device, while air is introduced through the nitrous oxide inlet. The air inlet is then closed, and the second flow rate displayed by the nitrous oxide electronic flow meter is obtained when the preset flow rate value is displayed. Step 7 specifically includes: Based on the ratio of the fixed flow rate value, the second flow rate value, and the verification conversion coefficient corresponding to the preset flow rate value, and the preset accuracy error of the Xiaokong electronic flow meter, the range of verification flow rates corresponding to the preset flow rate value is determined. Step 8 specifically includes: If the third flow rate value displayed by the gas flow detection device is within the range of the verification flow rate value corresponding to the preset flow rate value, then it is determined that the accuracy of the Xiaokong electronically controlled flow meter meets the standard.

[0010] In some embodiments, the first flow control branch includes a nitrous oxide inlet composed of a nitrous oxide solenoid valve, an air inlet composed of an air solenoid valve, an air-nitrous oxide proportional valve connected to the nitrous oxide solenoid valve and the air solenoid valve, and a nitrous oxide-air electro-hydraulic flow meter connected to the air-nitrous oxide proportional valve; the second flow control branch includes an oxygen inlet composed of an oxygen solenoid valve, an oxygen proportional valve connected to the oxygen solenoid valve, and an oxygen electro-hydraulic flow meter connected to the oxygen proportional valve. Step 3 specifically includes: Open the air solenoid valve and the oxygen solenoid valve to allow oxygen to enter through the oxygen inlet of the second flow control branch in the flow control system and be introduced into the atmosphere. Open the nitrous oxide solenoid valve, close the air solenoid valve and open the air-nitrous oxide proportional valve to the opening degree corresponding to the preset flow value, so that air enters through the nitrous oxide inlet. When the nitrous oxide electric flow meter displays the preset flow value, obtain the first flow value recorded by the gas flow detection device.

[0011] In some embodiments, step 6 specifically includes: Open the air solenoid valve and the oxygen proportional valve to the opening degree corresponding to the fixed flow value, so that the oxygen of the fixed flow value enters through the oxygen inlet of the second flow control branch and flows through the gas flow detection device. Open the nitrous oxide solenoid valve, close the air solenoid valve and open the air-nitrous oxide proportional valve, so that air enters through the nitrous oxide inlet, and obtain the second flow value displayed by the nitrous oxide electronic flow meter.

[0012] Compared with existing technologies, the advantages of this application are: (1) It is replaceable. Before the anesthesia machine leaves the factory, the accuracy of the nitrous oxide flow output of the nitrous oxide electronic flow meter can be tested and verified by air instead of nitrous oxide. (2) No pollution: The method of using air instead of nitrous oxide to test the accuracy of the nitrous oxide electric flow meter can avoid the emission of nitrous oxide into the atmosphere during the testing process and thus avoid environmental pollution. (3) Low cost: Air can be obtained from a compressor, which is very inexpensive. Compared with nitrous oxide, the procurement cost of nitrous oxide is much higher. (4) Reduce procurement difficulty. Nitrous oxide is a hazardous chemical, and some regions restrict enterprises from purchasing it. Compared with air, air is very easy to obtain. (5) Safety: The method of using air instead of nitrous oxide to test the accuracy of the electronic flow meter can avoid the health impact of the test personnel due to inhaling nitrous oxide; (6) The anesthesia machine does not need to be disassembled during factory inspection, which improves the efficiency of factory inspection. Attached Figure Description

[0013] Figure 1This is a schematic diagram of the flow control system provided in this application. Figure 2 This is a schematic diagram of the accuracy testing method for an electrically controlled flowmeter in an anesthesia machine provided in this application.

[0014] Reference numerals: 1. Nitrous oxide solenoid valve; 2. Air solenoid valve; 3. Oxygen solenoid valve; 4. Air-nitrous oxide proportional valve; 5. Nitrous oxide-air electrically controlled flow meter; 6. Oxygen proportional valve; 7. Oxygen electrically controlled flow meter. Detailed Implementation

[0015] The technical solution of this application will be described in detail below with reference to the accompanying drawings and embodiments.

[0016] This application provides a method for detecting the accuracy of an electrically controlled flowmeter in an anesthesia machine, applicable to... Figure 1 In the flow control system of the anesthesia machine shown, as... Figure 1 As shown, the flow control system includes a first flow control branch and a second flow control branch. The first flow control branch includes a nitrous oxide inlet consisting of a nitrous oxide solenoid valve 1, an air inlet consisting of an air solenoid valve 2, an air-nitrous oxide proportional valve 4 connected to the nitrous oxide solenoid valve 1 and the air solenoid valve 2, and a nitrous oxide-air flow meter 5 connected to the air-nitrous oxide proportional valve 4. The nitrous oxide-air flow meter 5 is used to detect the flow rate of nitrous oxide and / or air in the anesthesia machine. The second flow control branch includes an oxygen inlet consisting of an oxygen solenoid valve 3, an oxygen proportional valve 6 connected to the oxygen solenoid valve 3, and an oxygen flow meter 7 connected to the oxygen proportional valve 6.

[0017] The working principle of the flow control system is as follows: When a specified flow rate of fresh oxygen needs to be controlled, the anesthesia machine supplies power to the oxygen solenoid valve 3, which opens, thus opening the second flow control branch and the oxygen gas path. At the same time, the circuit board supplies a certain current to the oxygen proportional valve 6. After being energized, the oxygen proportional valve 6 moves from the closed position to a certain open position, resulting in a certain flow rate output. The outflowing oxygen gas is detected by the oxygen electronic flow meter 7. If the flow rate detected by the oxygen electronic flow meter 7 is inconsistent with the set value, the circuit board will change the current supplied to the oxygen proportional valve 6, adjusting the opening size of the oxygen proportional valve 6. The oxygen electronic flow meter 7 can accurately detect the gas flow rate, thereby achieving the consistency between the oxygen flow rate output and the set value, realizing the electronic control function of high-precision oxygen flow rate output. Similarly, when a certain air flow rate is set, the anesthesia machine supplies power to the air solenoid valve 2, which opens the air path. At the same time, the circuit board supplies a certain current to the air proportional valve 4. After being energized, the air proportional valve 4 moves from the closed position to a certain open position, resulting in a certain flow rate output. The outflowing air is detected by the air electronic flow meter 5. If the flow rate detected by the air electronic flow meter 5 is inconsistent with the set value, the circuit board will change the current supplied to the air proportional valve 4, adjusting the opening size of the air proportional valve 4. The air electronic flow meter 7 can accurately detect the gas flow rate, thereby achieving the air flow output consistent with the set value and realizing the electronic control function of high-precision air flow output. Similarly, when a certain flow rate of nitrous oxide is set, the anesthesia machine supplies power to the nitrous oxide solenoid valve 1, which opens, thus opening the nitrous oxide gas path. At the same time, the circuit board supplies a certain current to the nitrous oxide proportional valve 4. After being energized, the valve 4 moves from the closed position to a certain open position, resulting in a certain flow rate output. The outflowing nitrous oxide gas is detected by the nitrous oxide-electric flow meter 5. If the flow rate detected by the nitrous oxide-electric flow meter 5 is inconsistent with the set value, the circuit board will change the current supplied to the nitrous oxide proportional valve 4, adjusting the opening size of the valve. The nitrous oxide-electric flow meter 5 can accurately detect the gas flow rate, thereby ensuring that the output nitrous oxide flow rate is consistent with the set value, achieving a high-precision electronic control function for nitrous oxide flow rate output.

[0018] The nitrous oxide electric flow meter 5 and oxygen electric flow meter 7 in the flow control system are thermal flow sensors. Their principle is to determine the fluid velocity by measuring the asymmetric temperature change at both ends of the heater caused by fluid flow. A temperature sensor is placed at an equal distance at each end of the heater, and a voltage is applied to the heater, creating a temperature field distribution symmetrical to the heater. When the fluid velocity is zero, the temperature difference between the two temperature sensors is zero; when fluid flows through the channel, the temperature field exhibits an asymmetric distribution. The greater the flow velocity, the greater the asymmetry, and the greater the temperature difference between the two temperature sensors. The fluid velocity can be determined through calibration. The conversion coefficient of the thermal flow sensor using air instead of nitrous oxide needs to be calculated using a formula. Theoretically, the conversion coefficient of nitrous oxide is usually between 0.6 and 0.8, but the specific value needs to be adjusted based on the equipment calibration parameters and gas characteristics.

[0019] Specifically, the flow calculation formula for a thermal flow sensor is as follows: Q = K × A ÷ Cp × ΔT In the formula: A -- the thermal conductivity coefficient between the heat exchange system around the temperature sensing element; Cp is the isobaric specific heat capacity of the gas being measured; K -- the instrument coefficient; ΔT -- the average temperature difference between the two temperature sensing elements.

[0020] When measuring the flow rates of different gas types using the same thermal flow sensor, the relationship between the output flow rates and the parameters A and Cp is related. Therefore, the conversion coefficient between nitrous oxide and air is equal to the ratio of the A / Cp value of nitrous oxide to the A / Cp value of air. The parameter values ​​of A and Cp for nitrous oxide and air are as follows:

[0021] The theoretical conversion coefficient between nitrous oxide and air is calculated to be (0.015÷870)÷(0.026÷1005)≈0.67.

[0022] Based on the calculated theoretical conversion coefficient of 0.67 between nitrous oxide and air, the actual conversion coefficient between nitrous oxide and air in the nitrous oxide-air electronic flow meter can be obtained through testing. Comparing the theoretical and actual conversion coefficients, if they are close to 0.67, the theoretical conversion coefficient of 0.67 can be directly adopted, and the acceptable inspection range related to nitrous oxide flow output can be calculated. Then, testing can be used to verify whether the calculated acceptable inspection range and conversion coefficient are reasonable. If the deviation from 0.67 is too large and falls between 0.6 and 0.8, the measured conversion coefficient should be adopted, and the acceptable inspection range related to nitrous oxide flow output can be calculated. Then, testing can be used to verify whether the calculated acceptable inspection range and conversion coefficient are reasonable. After verifying that the acceptable inspection range is reasonable, this can be used as the basis for batch inspection of inspection items related to nitrous oxide flow output.

[0023] Specifically, the specific steps of the accuracy detection method for the electrically controlled flowmeter in the anesthesia machine according to embodiments of this application are as follows: Figure 2 As shown, it includes: Step 1: Connect the gas flow detection device to the flow control system.

[0024] In this embodiment, when testing the accuracy of the nitrous oxide flow meter in an anesthesia machine, the following steps are prepared: an oxygen cylinder, an air cylinder, a nitrous oxide cylinder, a gas flow detection device, a connecting pipe between the flow control system of the anesthesia machine and the cylinders, and a connecting pipe between the auxiliary fresh gas outlet switch (ACGO) of the anesthesia machine and the inlet of the gas flow detection device. The oxygen cylinder provides sufficient oxygen (i.e., oxygen source), the air cylinder provides sufficient air (i.e., air source), and the nitrous oxide cylinder provides sufficient nitrous oxide (i.e., nitrous oxide source). The anesthesia machine has an auxiliary fresh gas outlet switch, which is a two-position three-way valve. After opening the auxiliary fresh gas outlet switch, the gas flow rate output by the anesthesia machine flows directly from the outlet of the auxiliary fresh gas outlet switch without passing through the anesthesia machine's circuit. Connecting the gas flow detection device to the auxiliary fresh gas outlet switch allows for the detection of the gas flow rate from the flow control system.

[0025] Specifically, the gas flow detection device can accurately detect the flow rates of air, oxygen, nitrous oxide, oxygen-air mixtures, and oxygen-nitrous oxide mixtures. It offers four gas flow detection modes: manual for air, manual for oxygen-air, automatic for oxygen-air, manual for oxygen-nitrous oxide, and automatic for oxygen-nitrous oxide. To measure oxygen flow rate, use the manual oxygen-air mode with an oxygen concentration of 100%; to measure the flow rate of the oxygen-air mixture, use the automatic oxygen-air mode; to measure nitrous oxide flow rate, use the manual oxygen-nitrous oxide mode with an oxygen concentration of 0%; and to measure the flow rate of the oxygen-nitrous oxide mixture, use the automatic oxygen-nitrous oxide mode.

[0026] Specifically, the inner diameter of the connecting pipe between the auxiliary fresh gas outlet switch of the anesthesia machine and the inlet of the gas flow detection device should be at least 12 mm to ensure the accuracy of the detected flow output.

[0027] Specifically, the gas flow detection mode of the gas flow detection device must be consistent with the flow detection mode of the anesthesia machine. For example, if the anesthesia machine's flow detection mode is ATP, then the gas flow detection device needs to be adjusted to ATP mode. To prevent the oxygen concentration of the fresh gas inhaled by the patient from being too low, the anesthesia machine cannot have its nitrous oxide flow rate set independently; it can only be set when oxygen is being output, and the ratio of nitrous oxide flow rate output to oxygen flow rate output should not exceed 3:1. Before the anesthesia machine leaves the factory, the output accuracy of the electronically controlled flowmeter does not require disassembling the machine or replacing the tubing. The electronically controlled flowmeter cannot output nitrous oxide independently; however, the flow output accuracy of oxygen, air, oxygen-air mixture, and oxygen-nitrous oxide mixture (using air instead of nitrous oxide as the test gas) can be tested without disassembling the machine. Specifically, the oxygen cylinder, air cylinder, and oxygen cylinder are each connected to the cylinder via a connecting pipe between the anesthesia machine and the cylinder to prevent leakage. The outlet of the auxiliary fresh gas outlet switch is connected to the inlet of the gas flow detection device via a connecting pipe.

[0028] Step 2: Perform accuracy calibration on the gas flow detection device.

[0029] In this embodiment, after the gas flow detection device is installed, its accuracy is calibrated. This calibration may include single gas flow rate calibration and mixed gas flow rate calibration. This ensures that the gas flow detection device's readings match those of the air-controlled flow meter, thus meeting the accuracy requirements.

[0030] Step 3: When calibration is complete, allow oxygen to enter through the oxygen inlet of the second flow control branch in the flow control system and be introduced into the atmosphere, allow air to enter through the nitrous oxide inlet, close the air inlet, and when the nitrous oxide electronic flow meter displays the preset flow value, obtain the first flow value recorded by the gas flow detection device.

[0031] In this embodiment of the application, when calibration is completed, the second flow control branch of the flow control system is connected to the atmosphere. Even if oxygen enters through the oxygen inlet of the second flow control branch in the flow control system and is introduced into the atmosphere, the nitrous oxide inlet of the first flow control branch is used to transport air. Even if air enters through the nitrous oxide inlet, the air inlet is closed. Thus, when the nitrous oxide electronic flow meter displays the preset flow value, the first flow value recorded by the gas flow detection device can be obtained.

[0032] Specifically, the air solenoid valve 2 and the oxygen solenoid valve 3 are opened to allow oxygen to enter through the oxygen inlet of the second flow control branch in the flow control system and be introduced into the atmosphere. The nitrous oxide solenoid valve 1 is opened, the air solenoid valve 2 is closed, and the air-nitrous oxide proportional valve 4 is opened to the opening degree corresponding to the preset flow value, so that air enters through the nitrous oxide inlet. When the nitrous oxide electric flow meter 5 displays the preset flow value, the first flow value recorded by the gas flow detection device is obtained.

[0033] Specifically, step 3 of this embodiment can be performed multiple times, meaning there are multiple preset flow rates, each corresponding to a different first flow rate detected by the gas flow detection device. For example, the preset values ​​may include 1L / min, 6L / min, and 10L / min. When the preset value is 1L / min, the value displayed by the nitrous oxide electronic flow meter is 1L / min, and the gas flow detection device displays the first flow rate.

[0034] Step 4: Calculate the first conversion coefficient for different preset flow rates based on the ratio of the preset flow rate value to the first flow rate value corresponding to the preset flow rate.

[0035] In this embodiment of the application, after obtaining multiple preset flow values ​​and the first flow value corresponding to the preset flow, the Xiaokong conversion coefficient is calculated for different preset flow values ​​according to the ratio of the preset flow value to the first flow value corresponding to the preset flow.

[0036] Step 5: Determine the verification conversion coefficient based on multiple Laughing Space conversion coefficients.

[0037] In this embodiment, after obtaining multiple first conversion coefficients, a verification conversion coefficient is determined based on these multiple first conversion coefficients. Specifically, the verification conversion coefficient can be determined based on the magnitude of the multiple first conversion coefficients and the theoretical conversion coefficient.

[0038] In one example, if the difference between the maximum and minimum values ​​of multiple first conversion coefficients does not exceed 0.03, and the minimum value of all first conversion coefficients is greater than the theoretical conversion coefficient of 0.03, then the average value of the multiple first conversion coefficients is determined as the verification conversion coefficient; if the difference between the maximum and minimum values ​​of multiple first conversion coefficients does not exceed 0.03, and the maximum value of all first conversion coefficients is less than the theoretical conversion coefficient of 0.03, then the theoretical conversion coefficient is determined as the verification conversion coefficient; if the multiple first conversion coefficients are different, or the values ​​of the multiple first conversion coefficients gradually increase or gradually decrease, and when gradually increasing, the minimum value of the multiple first conversion coefficients is greater than the theoretical conversion coefficient of 0.03, or when gradually decreasing, the minimum value of the multiple first conversion coefficients is less than the theoretical conversion coefficient of 0.03, then each preset flow rate value corresponds to a different conversion coefficient.

[0039] For example, if the preset values ​​are 1 L / min, 6 L / min, and 10 L / min, the flow rate values ​​detected by the gas flow detection device are recorded at these preset values, and the nitrous oxide to air ratios (first conversion coefficients) are obtained as k1, k2, and k3, respectively. If the difference between the maximum and minimum values ​​of k1, k2, and k3 does not exceed 0.03 and is between 0.6 and 0.8, but the difference between the minimum value of k1, k2, and k3 and 0.67 is greater than 0.03, the average conversion coefficient k is used for verification. If the difference between the maximum and minimum values ​​of k1, k2, and k3 does not exceed 0.03, and the maximum value of k1, k2, and k3 is less than the theoretical conversion coefficient of 0.03, then the theoretical conversion coefficient is used. The conversion coefficients are determined as follows: If the obtained k1, k2, and k3 are different, or if the values ​​of k1, k2, and k3 gradually increase or decrease, and the minimum value among k1, k2, and k3 is greater than the theoretical conversion coefficient of 0.03 when gradually increasing, or less than the theoretical conversion coefficient of 0.03 when gradually decreasing, then each preset flow rate value corresponds to a first conversion coefficient. The ratio of nitrous oxide to air (first conversion coefficient) can be k1, k2, and k3 at different flow rates. That is, when the preset value is 1 L / min, the conversion coefficient is k1; when the preset value is 6 L / min, the conversion coefficient is k2; and when the preset value is 10 L / min, the conversion coefficient is k3.

[0040] Step 6: Allow oxygen of a fixed flow rate to enter through the oxygen inlet of the second flow control branch and flow through the gas flow detection device, allow air to enter through the nitrous oxide inlet, close the air inlet, and obtain the second flow rate value displayed by the nitrous oxide electronic flow meter.

[0041] In this embodiment of the application, after obtaining the verification conversion coefficient, the second flow control branch is connected to the gas flow detection device so that oxygen can flow through the flow detection device. Even if oxygen with a fixed flow value enters through the oxygen inlet of the second flow control branch and flows through the gas flow detection device, air is allowed to enter through the nitrous oxide inlet, the air inlet is closed, and the second flow value displayed by the nitrous oxide electronic flow meter 5 is obtained.

[0042] Specifically, the air solenoid valve 2 is opened, and the oxygen proportional valve 6 is opened to the opening degree corresponding to the fixed flow value, so that the oxygen of the fixed flow value enters through the oxygen inlet of the second flow control branch and flows through the gas flow detection device. The nitrous oxide solenoid valve 1 is opened, the air solenoid valve 2 is closed, and the air-nitrous oxide proportional valve 4 is opened, so that air enters through the nitrous oxide inlet and the second flow value displayed by the nitrous oxide-air electronic flow meter 5 is obtained.

[0043] In one example, a fixed oxygen flow rate of 6 L / min can be set, and any amount of air can be introduced through the nitrous oxide inlet to obtain the second flow rate value displayed by the nitrous oxide electronic flow meter.

[0044] In one example, a second flow rate value can also be obtained by setting the flow rate value displayed by the Xiaokong electronically controlled flow meter. For example, the Xiaokong electronically controlled flow meter can be set to 1L / min, thus obtaining a second flow rate value of 1L / min displayed by the Xiaokong electronically controlled flow meter.

[0045] Step 7: Determine the range of verification flow values ​​based on the ratio of the fixed flow value, the second flow value, and the verification conversion coefficient, as well as the preset accuracy error of the Xiaokong electric flow meter.

[0046] In this embodiment of the application, after obtaining the fixed flow rate value, the ratio of the second flow rate value to the verification conversion coefficient, and the accuracy error of the Xiaokong electric flow meter, the verification flow rate error range is determined based on the fixed flow rate value, the ratio of the second flow rate value to the verification conversion coefficient, and the accuracy error of the Xiaokong electric flow meter.

[0047] In one example, if the fixed flow rate is 6 L / min, the second flow rate is 1 L / min, and the accuracy error is m%, then the obtained verification flow rate error range is: (6+1÷k)±m.

[0048] In one example, the fixed flow rate is 6 L / min, the second flow rate is 5 L / min, and the accuracy error is m%. The obtained verification flow rate error range is (6 + 5 ÷ k) ± m.

[0049] In one example, the fixed flow rate is 6 L / min, the second flow rate is 10 L / min, and the accuracy error is m%. The obtained verification flow rate error range is (6 + 10 ÷ k) ± m.

[0050] In one example, the preset precision error m% can be 10%.

[0051] Furthermore, based on the values ​​obtained in step 5, if the verification conversion coefficient is k, the fixed flow rate is 6 L / min, and the second flow rate is 1 L / min, 5 L / min, and 10 L / min, the verification flow rate error range is: (6+1÷k)±m%, (6+5÷k)±m%, and (6+10÷k)±m%; if the verification conversion coefficient is 0.67, the fixed flow rate is 6 L / min, and the second flow rate is 1 L / min, 5 L / min, and 10 L / min. The verification flow rate error range is: (6+1÷0.67)±m%, (6+5÷0.67)±m% and (6+10÷0.67)±m%; if the verification conversion coefficients are k1, k2 and k3 respectively, the fixed flow rate is 6L / min, the second flow rate is 1L / min, 5L / min and 10L / min, the verification flow rate error range is: (6+1÷k1)±m%, (6+5÷k2)±m% and (6+10÷k3)±m.

[0052] Step 8: If the third flow value displayed by the gas flow detection device is within the range of the verified flow value, then it is determined that the accuracy of the Xiaokong electric flow meter meets the standard.

[0053] In this embodiment of the application, after obtaining the verified flow rate range, the third flow rate value displayed by the gas flow detection device is read. This flow rate value is the flow rate value of the air and oxygen mixture. If the third flow rate value displayed by the gas flow detection device is within the verified flow rate range, it is determined that the accuracy of the Xiaokong electronic flow meter meets the standard, and it is further determined that the anesthesia machine meets the factory requirements.

[0054] The accuracy detection method of the nitrous oxide-air-laughing gas electronically controlled flow meter in the anesthesia machine according to the embodiments of this application calculates the nitrous oxide-air-laughing gas conversion coefficient. The conversion ratio of air to nitrous oxide can be accurately calculated using the nitrous oxide-air-laughing gas conversion coefficient. This allows air to be used instead of nitrous oxide to perform accuracy detection of the nitrous oxide-air-laughing gas electronically controlled flow meter in the anesthesia machine, reducing gas procurement costs, avoiding harm to employees' health due to nitrous oxide inhalation during the testing process, and preventing environmental pollution.

[0055] Furthermore, step 2 in this embodiment specifically includes: Step 21: Close the nitrous oxide inlet and the air inlet, and allow oxygen to enter through the oxygen inlet at the first calibration flow rate value and flow through the gas flow detection device. If the flow rate value displayed by the gas flow detection device is different from the first calibration flow rate, calibrate the gas flow detection device.

[0056] In this embodiment, to ensure the accuracy of the oxygen single-tube flow output, the nitrous oxide inlet and air inlet are closed, allowing oxygen to enter through the oxygen inlet at the first calibration flow rate and flow through the gas flow detection device. Simultaneously, the gas flow detection device is set to a mode (oxygen-air manual mode, oxygen concentration set to 100%, ATP), and the anesthesia machine's gas flow mode is ATP. Specifically, the first calibration flow rate for oxygen can be 1, 5, or 10 L / min, with other flow rates closed. The flow rate value detected by the gas flow detection device is recorded. If the flow rate value displayed by the gas flow detection device differs from the first calibration flow rate, the gas flow detection device is calibrated to ensure that it meets the accuracy requirements of the oxygen electronic flowmeter's flow output.

[0057] Step 22: Close the nitrous oxide inlet and the oxygen inlet, and allow air to enter through the air inlet at the second calibration flow rate value and flow through the gas flow detection device. If the flow rate value displayed by the gas flow detection device is different from the second calibration flow rate, calibrate the gas flow detection device.

[0058] In this embodiment, to ensure the accuracy of the single-tube air flow output, the nitrous oxide inlet and oxygen inlet are closed, allowing air to enter through the air inlet at the second calibration flow rate value and flow through the gas flow detection device. Specifically, the second calibration flow rate value of the air can be 1, 5, or 12 L / min, with other flow rates closed. The flow rate value detected by the gas flow detection device is recorded. If the flow rate value displayed by the gas flow detection device is different from the second calibration flow rate, the gas flow detection device is calibrated to ensure that the gas flow detection device meets the accuracy requirements of the nitrous oxide electronic flowmeter's flow output.

[0059] Step 23: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the third calibration flow rate, and flow through the gas flow detection device. Allow oxygen to enter through the oxygen inlet and flow into the atmosphere. If the flow rate displayed by the gas flow detection device is different from the third calibration flow rate, calibrate the gas flow detection device.

[0060] In this embodiment, to ensure the accuracy of the nitrous oxide single-tube flow output, the air inlet is closed, allowing nitrous oxide to enter through the nitrous oxide inlet at the third calibration flow rate and flow through the gas flow detection device. Oxygen enters through the oxygen inlet and flows into the atmosphere, ensuring that the gas flow detected by the gas flow detection device only shows the nitrous oxide flowing out of the nitrous oxide outlet. Specifically, the gas flow detection device is set to oxygen-nitrous oxide manual mode, with the oxygen concentration adjusted to 0 and the gas type ATP. The oxygen flow rate can be set to 6 L / min, and the third calibration flow rate of nitrous oxide can be set to 1, 5, or 10 L / min. The flow rate value detected by the gas flow detection device is recorded. When the flow rate value displayed by the gas flow detection device differs from the third calibration flow rate, the gas flow detection device is calibrated to ensure that it meets the accuracy requirements of the nitrous oxide electronic flow meter's flow output.

[0061] Step 24: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the fourth calibration flow rate and flow through the gas flow detection device, and allow oxygen to enter through the oxygen inlet at the fifth calibration flow rate and flow through the gas flow detection device. If the flow rate value displayed by the gas flow detection device is different from the first mixed flow rate value, calibrate the gas flow detection device.

[0062] In this embodiment, to ensure the accuracy of the oxygen-nitrobenzene mixed flow rate output, the oxygen inlet, air inlet, and nitrobenzene inlet of the flow control system are connected to oxygen cylinders, air cylinders, and nitrobenzene cylinders, respectively. The outlet of the mixed flow rate of the electronically controlled flow meter is connected to the inlet of ACGO, i.e., the air inlet is closed, allowing nitrobenzene to enter through the nitrobenzene inlet at the fourth calibration flow rate value and flow through the gas flow detection device, and allowing oxygen to enter through the oxygen inlet at the fifth calibration flow rate value and flow through the gas flow detection device. The flow rate setting mode of the gas flow detection device is the oxygen-nitrobenzene automatic mode, the gas type is ATP, the fifth calibration flow rate value of oxygen can be set to 6 L / min, and the fourth calibration flow rate value of nitrobenzene can be set to 1, 5, or 10 L / min. The flow rate values ​​detected by the gas flow detection device are recorded respectively. The recorded gas (oxygen-nitrobenzene mixed gas) flow rate value detected by the gas flow detection device must meet the flow output accuracy of the electronically controlled flow meter, i.e., when the flow rate value (oxygen-nitrobenzene mixed gas flow rate value) displayed by the gas flow detection device is different from the first mixed flow rate value, the gas flow detection device is calibrated; wherein, the first mixed flow rate value is determined based on the sum of the fourth calibration flow rate and the fifth calibration flow rate.

[0063] Step 25: Close the nitrous oxide inlet, allow air to enter through the air inlet at the sixth calibration flow rate and flow through the gas flow detection device, and allow oxygen to enter through the oxygen inlet at the seventh calibration flow rate and flow through the gas flow detection device. If the flow rate value displayed by the gas flow detection device is different from the second mixed flow rate value, calibrate the gas flow detection device.

[0064] In this embodiment, to ensure the accuracy of the oxygen-air mixed flow output, the oxygen inlet, air inlet, and nitrous oxide inlet of the flow control system are connected to oxygen cylinders, air cylinders, and nitrous oxide cylinders, respectively. The outlet of the nitrous oxide-air electronic flow meter is connected to the ACGO inlet. The nitrous oxide inlet is closed, allowing air to enter through the air inlet at the sixth calibration flow value and flow through the gas flow detection device. Similarly, allowing oxygen to enter through the oxygen inlet at the seventh calibration flow value and flow through the gas flow detection device. The gas flow detection device is set to an oxygen-air automatic mode, with the gas type being ATP. The seventh calibration flow value for oxygen can be set to 6 L / min, and the sixth calibration flow value for air can be set to 1, 5, or 10 L / min. The flow values ​​detected by the gas flow detection device are recorded. The recorded gas (oxygen-air mixed gas) flow values ​​detected by the gas flow detection device must meet the flow output accuracy of the electronic flow meter. That is, when the flow value displayed by the gas flow detection device is different from the second mixed flow value, the gas flow detection device is calibrated. The second mixed flow value is determined by the sum of the sixth and seventh calibration flow values.

[0065] Furthermore, the flow control system of this application consists of a nitrous oxide solenoid valve 1, an air solenoid valve 2, an oxygen solenoid valve 3, an air-nitrous oxide proportional valve 4, a nitrous oxide-air electrically controlled flow meter 5, an oxygen proportional valve 6, and an oxygen electrically controlled flow meter 7, with the gas path built into an integrated block.

[0066] Furthermore, according to the accuracy testing method and calculation sequence of the nitrous oxide-air-electric flow meter in the anesthesia machine according to the embodiments of this application, and meeting the requirements of the above test items, the mass-produced anesthesia machines can determine the scheme of using air instead of nitrous oxide to test the accuracy of the electric flow meter when the machine is not disassembled during factory inspection. That is, when testing the accuracy of the oxygen-nitrous oxide mixed flow output, the test gas is air instead of nitrous oxide. If the flow value of the oxygen-nitrous oxide mixed flow output is within the calculated flow range, it can prove the accuracy of the nitrous oxide flow output of the electric flow meter.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. A method for detecting the accuracy of an electrically controlled flowmeter in an anesthesia machine, characterized in that, A nitrous oxide inlet and an air inlet are installed in the first flow control branch of the flow control system in the anesthesia machine. The first flow control branch includes a nitrous oxide inlet and an air inlet. The method includes: Step 1: Connect the gas flow detection device to the flow control system; Step 2: Perform accuracy calibration on the gas flow detection device; Step 3: When calibration is complete, oxygen is introduced into the atmosphere through the oxygen inlet of the second flow control branch in the flow control system, and air is introduced through the nitrous oxide inlet. The air inlet is closed. When the nitrous oxide electronic flow meter displays a preset flow value, the first flow value recorded by the gas flow detection device is obtained. The preset flow value includes multiple values, and each preset value corresponds to a different first flow value. Step 4: Calculate the first conversion coefficient for different preset flow rates based on the ratio of the preset flow rate value to the first flow rate value corresponding to the preset flow rate; Step 5: Determine the verification conversion coefficients based on the multiple first conversion coefficients; Step 6: Allow oxygen of a fixed flow rate to enter through the oxygen inlet of the second flow control branch and flow through the gas flow detection device, allow air to enter through the nitrous oxide inlet, close the air inlet, and obtain the second flow rate value displayed by the nitrous oxide electronic flow meter. Step 7: Determine the range of verification flow values ​​based on the fixed flow value, the ratio of the second flow value to the verification conversion coefficient, and the preset accuracy error of the Xiaokong electronic flow meter; Step 8: If the third flow value displayed by the gas flow detection device is within the range of the verified flow value, then it is determined that the accuracy of the Xiaokong electronic flow meter meets the standard.

2. The accuracy detection method according to claim 1, characterized in that, Step 2 specifically includes: Step 21: Close the nitrous oxide inlet and the air inlet, and allow oxygen to enter through the oxygen inlet at the first calibration flow rate value and flow through the gas flow detection device. When the flow rate value displayed by the gas flow detection device is different from the first calibration flow rate, calibrate the gas flow detection device. Step 22: Close the nitrous oxide inlet and the oxygen inlet, and allow air to enter through the air inlet at the second verification flow rate value and flow through the gas flow detection device. When the flow rate value displayed by the gas flow detection device is different from the second verification flow rate, calibrate the gas flow detection device. Step 23: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the third verification flow rate value, and flow through the gas flow detection device. Allow oxygen to enter through the oxygen inlet and flow into the atmosphere. If the flow rate value displayed by the gas flow detection device is different from the third verification flow rate, calibrate the gas flow detection device.

3. The accuracy detection method according to claim 2, characterized in that, Step 2 may also include the following steps: Step 24: Close the air inlet, allow nitrous oxide to enter through the nitrous oxide inlet at the fourth verification flow rate value and flow through the gas flow detection device, allow oxygen to enter through the oxygen inlet at the fifth verification flow rate value and flow through the gas flow detection device, and when the flow rate value displayed by the gas flow detection device is different from the first mixed flow rate value, calibrate the gas flow detection device, wherein the first mixed flow rate value is determined based on the sum of the fourth verification flow rate and the fifth verification flow rate; Step 25: Close the nitrous oxide inlet, allow air to enter through the air inlet at the sixth calibration flow rate and flow through the gas flow detection device, allow oxygen to enter through the oxygen inlet at the seventh calibration flow rate and flow through the gas flow detection device, and when the flow rate value displayed by the gas flow detection device is different from the second mixed flow rate value, calibrate the gas flow detection device, wherein the second mixed flow rate value is determined based on the sum of the sixth calibration flow rate and the seventh calibration flow rate.

4. The accuracy detection method according to claim 1, characterized in that, Step 5 specifically includes: Obtain the theoretical conversion coefficient; If the difference between the maximum and minimum values ​​among the plurality of first conversion coefficients does not exceed 0.03, and the minimum value among the plurality of first conversion coefficients is greater than the theoretical conversion coefficient of 0.03, then the average value of the plurality of first conversion coefficients is determined as the verification conversion coefficient; If the difference between the maximum and minimum values ​​among the plurality of first conversion coefficients does not exceed 0.03, and the maximum value of the plurality of first conversion coefficients is less than the theoretical conversion coefficient of 0.03, then the theoretical conversion coefficient is determined as the verification conversion coefficient; If the multiple first conversion coefficients are different, the magnitude of the multiple first conversion coefficients gradually increases or gradually decreases, and when gradually increasing, the minimum value among the multiple first conversion coefficients is greater than the theoretical conversion coefficient 0.03, or when gradually decreasing, the minimum value among the multiple first conversion coefficients is less than the theoretical conversion coefficient 0.03, then it is determined that each of the preset flow rates corresponds to a first conversion coefficient.

5. The accuracy detection method according to claim 1, characterized in that, Step 6 specifically includes: Oxygen with a fixed flow rate is introduced through the oxygen inlet of the second flow control branch and flows through the gas flow detection device, while air is introduced through the nitrous oxide inlet. The air inlet is then closed, and the second flow rate displayed by the nitrous oxide electronic flow meter is obtained when the preset flow rate value is displayed. Step 7 specifically includes: Based on the ratio of the fixed flow rate value, the second flow rate value, and the verification conversion coefficient corresponding to the preset flow rate value, and the preset accuracy error of the Xiaokong electronic flow meter, the range of verification flow rates corresponding to the preset flow rate value is determined. Step 8 specifically includes: If the third flow rate value displayed by the gas flow detection device is within the range of the verification flow rate value corresponding to the preset flow rate value, then it is determined that the accuracy of the Xiaokong electronically controlled flow meter meets the standard.

6. The accuracy detection method according to claim 1, characterized in that, The first flow control branch includes a nitrous oxide inlet consisting of a nitrous oxide solenoid valve, an air inlet consisting of an air solenoid valve, an air-nitrous oxide proportional valve connected to the nitrous oxide solenoid valve and the air solenoid valve, and a nitrous oxide-air proportional flow meter connected to the air-nitrous oxide proportional valve; the second flow control branch includes an oxygen inlet consisting of an oxygen solenoid valve, an oxygen proportional valve connected to the oxygen solenoid valve, and an oxygen proportional flow meter connected to the oxygen proportional valve. Step 3 specifically includes: Open the air solenoid valve and the oxygen solenoid valve to allow oxygen to enter through the oxygen inlet of the second flow control branch in the flow control system and be introduced into the atmosphere. Open the nitrous oxide solenoid valve, close the air solenoid valve and open the air-nitrous oxide proportional valve to the opening degree corresponding to the preset flow value, so that air enters through the nitrous oxide inlet. When the nitrous oxide electric flow meter displays the preset flow value, obtain the first flow value recorded by the gas flow detection device.

7. The accuracy detection method according to claim 6, characterized in that, Step 6 specifically includes: Open the air solenoid valve and the oxygen proportional valve to the opening degree corresponding to the fixed flow value, so that the oxygen of the fixed flow value enters through the oxygen inlet of the second flow control branch and flows through the gas flow detection device. Open the nitrous oxide solenoid valve, close the air solenoid valve and open the air-nitrous oxide proportional valve, so that air enters through the nitrous oxide inlet, and obtain the second flow value displayed by the nitrous oxide electronic flow meter.

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