Anesthesia machine APL valve and risk management method thereof

Abstract

This invention relates to the field of medical device technology, and more particularly to an APL valve for an anesthesia machine and its risk management method, comprising: acquiring knob calibration point information, setting magnetic components and a magnetic induction array; driving the knob to rotate to the calibration point, applying calibration pressure to construct a pressure-angle-voltage signal mapping table; acquiring real-time magnetic field data to obtain theoretical pressure values, and simultaneously acquiring real-time pressure values ​​of the circuit; calculating pressure errors to identify abnormal points; determining a standard test pressure based on the pressure error and actively applying it to obtain actual voltage signal values; calculating the difference between the actual voltage signal value and the standard value as a voltage compensation amount; adjusting the knob position according to the voltage compensation amount to obtain a compensated pressure setpoint; determining the risk based on the anesthesia machine's operating mode and the compensated pressure value, outputting the risk level, and executing proactive risk warnings. This invention can proactively diagnose mechanical degradation, automatically compensate for deviations, and provide warnings related to the operating mode, thereby improving the safety and reliability of the APL valve.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an APL valve for an anesthesia machine and its risk management method. Background Technology

[0002] The APL valve, a component of the anesthesia machine's breathing circuit, primarily limits the maximum pressure of the manual ventilation circuit (i.e., the spontaneous breathing circuit), ensuring the gas volume and pressure within a reasonable range and providing conditions for positive pressure ventilation. When spontaneous breathing resumes, the APL valve value needs to be adjusted to 0; otherwise, it will affect the patient's spontaneous breathing and may even lead to barotrauma. However, existing anesthesia machine APL valves are independent, purely mechanical components, lacking effective monitoring methods. In clinical practice, because the APL valve is inactive during mechanical ventilation and standby, the pressure value is easily overlooked when switching from manual to mechanical ventilation, making it somewhat concealed. Typically, the APL valve needs to be set to 0 in standby and mechanical control states, leading many staff to believe it is in a zero-value state, reducing their attention to the APL valve and further exacerbating its potential risks.

[0003] Chinese Patent Publication No. CN219167406U discloses an anesthesia system and an adjustable pressure limiting device. It includes an APL valve adjusting assembly and a valve core diaphragm assembly. The APL valve adjusting assembly comprises an upper valve seat, a knob, a pressure adjusting assembly, a position sensing assembly, and a floating assembly. The floating assembly is slidably connected to the upper valve seat. The upper end of the pressure adjusting assembly is fixed to the knob, and its lower end is spirally connected to the floating assembly and extends downwards from within it. The upper end of the valve core diaphragm assembly abuts against the floating assembly. When the knob is rotated, the position sensing assembly detects the rotation angle of the knob relative to the upper valve seat, thereby obtaining the downward pressure of the pressure adjusting assembly. It can also issue corresponding reminder signals based on different pressures, making it easier for the user to identify the adjusted pressure range. Furthermore, by using the floating assembly for elastic contact between the valve core diaphragm assembly and the APL valve adjusting assembly, assembly errors can be resolved, ensuring that the assembly of both is not affected by detachable connections.

[0004] Therefore, the aforementioned existing technology has the following problems: First, the device can only detect the rotation angle of the knob and cannot verify whether the pressure indicated by the knob matches the actual pressure in the circuit. When the APL valve experiences wear in the transmission mechanism, spring fatigue, or valve core jamming after long-term use, the knob's indicated position will deviate from the actual pressure. The operator may think that the correct pressure has been set, but the actual circuit pressure has deviated from the set value. Existing technology cannot detect this hidden fault.

[0005] Second, the device lacks proactive diagnostic capabilities. It can only passively detect the knob position and cannot actively apply stimuli to detect the health status of the APL valve. When early degradation of mechanical components occurs, it cannot proactively detect and provide early warnings, but can only respond passively after a failure occurs.

[0006] Third, the device cannot automatically compensate for deviations. When the knob position is detected, it can only issue a reminder signal, but it cannot automatically adjust the knob position to compensate for errors caused by mechanical wear or spring fatigue. It relies on manual intervention and is therefore unreliable.

[0007] Fourth, the device does not consider the relationship between the anesthesia machine's operating mode and the APL valve status. In mechanical ventilation mode or standby mode, the APL valve should be at zero, but if the operator forgets to do so, current technology cannot identify this risk, which may cause barotrauma to the patient when switching modes. Summary of the Invention

[0008] To address these issues, the present invention provides an APL valve for an anesthesia machine and a risk management method thereof, which overcomes the problems in the prior art that cannot verify the consistency between knob indication and circuit pressure, cannot actively diagnose mechanical degradation, cannot automatically compensate for deviations, and cannot correlate with working modes for risk warning.

[0009] To achieve the above objectives, the present invention provides a risk management method for an anesthesia machine APL valve, comprising: Step S1: Obtain the calibration point information of the knob of the APL valve of the anesthesia machine, and set a magnetic component on the knob of the APL valve of the anesthesia machine and set a magnetic induction array on the valve body to collect the voltage signal value output by the magnetic induction array during the rotation of the magnetic component with the knob. Step S2: Control the stepper motor to drive the knob to rotate to the corresponding calibration point, apply the calibration pressure corresponding to the calibration information at each calibration point, and collect the voltage signal value output by the magnetic induction array when the APL valve starts to depressurize, so as to determine the theoretical pressure setting value, knob rotation angle, voltage signal value and standard delay time corresponding to each calibration point, and construct a pressure-angle-voltage signal mapping table. Step S3: Continuously collect real-time magnetic field distribution data generated when the knob is rotated by the magnetic induction array; obtain the corresponding theoretical pressure setting value based on the pressure-angle-voltage signal mapping table; and simultaneously collect the real-time circuit pressure value measured by the pressure sensor in the breathing circuit of the anesthesia machine. Step S4: Calculate the pressure error between the theoretical pressure setpoint and the real-time pressure value of the circuit to identify abnormal points in each calibration point of the knob; Step S5: Determine the standard test pressure based on the absolute value of the pressure error, actively apply the standard test pressure to the abnormal point, and obtain the actual voltage signal value output by the magnetic induction array during the application process; Step S6: Calculate the difference between the actual voltage signal value and the standard voltage signal value in the mapping table as the voltage compensation amount. When the pressure setting value is zero and the loop pressure exceeds the zero threshold, the voltage compensation amount includes the zero-point compensation amount. Step S7: Adjust the knob position according to the voltage compensation amount to obtain the compensated pressure setting value; Step S8: Based on the current working mode of the anesthesia machine and the compensated pressure setting value, a risk assessment is performed to output a risk level, and an active risk warning operation corresponding to the risk level is executed based on the risk level.

[0010] Furthermore, each calibration point in step S1 includes the zero point position, the commonly used pressure point position, and the maximum pressure point position.

[0011] Furthermore, the standard test pressure mentioned in step S5 is proportional to the absolute value of the pressure error.

[0012] Furthermore, step S8 also includes: After compensation is completed, a verification pressure is applied to the breathing circuit to detect the verification error between the real-time pressure value of the circuit and the compensated pressure set value. If the verification error is less than the preset verification threshold, then the risk is determined by combining the current state of the anesthesia machine and the compensated pressure value, and the risk level is output. If the verification error is still greater than or equal to the preset verification threshold, the ring indicator light will be controlled to issue a maintenance alarm signal and output the voltage compensation amount and the verification error value.

[0013] Furthermore, in step S8, the multi-level risk assessment, which combines the current operating mode of the anesthesia machine and the compensated pressure setpoint, specifically includes: If the current working mode is mechanical ventilation mode or standby mode, and the compensated pressure setting value is not zero, it is determined to be the first risk level; If the current working mode is manual ventilation mode and the compensated pressure setting exceeds the preset safety threshold, it is determined to be the second risk level.

[0014] Furthermore, if the risk level is determined to be the first level, the control ring indicator light will issue a zeroing prompt signal; If the risk level is determined to be the second level, the control ring indicator light will issue a pressure over-limit alarm signal and activate the electronically controlled pressure relief valve to actively relieve pressure.

[0015] Furthermore, in the absence of risk warning, the ring indicator light is configured as follows: When the compensated pressure setpoint is zero, the control ring indicator light will turn off. When the compensated pressure setting value is within the first pressure range, the ring indicator light is controlled to emit a first color light, and the brightness of the light is proportional to the value of the compensated pressure setting value within the first pressure range. When the compensated pressure setting value is in the second pressure range, the control ring indicator light emits a second color light, and the brightness of the light is proportional to the value of the compensated pressure setting value in the second pressure range; When the compensated pressure setting value is in the third pressure range, the control ring indicator light emits a third color light, and the brightness of the light is proportional to the value of the compensated pressure setting value in the third pressure range.

[0016] On the other hand, the present invention also provides an APL valve for an anesthesia machine, comprising: A knob, used to adjust the working pressure value of the APL valve, including a magnetic component on the rotating part of the knob; The valve body is provided with a magnetic induction array, which cooperates with the magnetic component to collect real-time magnetic field distribution data generated when the knob is rotated, so as to obtain the rotation position of the knob. A stepper motor, connected to the knob, is used to drive the knob to rotate; A pressure sensor, which is installed in the breathing circuit of the anesthesia machine, is used to measure the real-time pressure value of the circuit; Pressure control unit, which is used to apply standard test pressure to the breathing circuit; A ring-shaped indicator light, arranged around the knob, is used to emit a light signal; An electrically controlled pressure relief valve is connected in parallel with the APL valve in the breathing circuit; The controller, which is electrically connected to the magnetic induction array, stepper motor, pressure sensor, pressure control unit, ring indicator and electrically controlled pressure relief valve respectively, is used to execute the risk management method of the APL valve of the anesthesia machine according to any one of claims 1-7 based on the acquired data.

[0017] Furthermore, the magnetic induction array includes a plurality of Hall sensors that are uniformly distributed in a ring; The magnetic component is a ring-shaped multipole magnet, which is coaxially arranged with the knob and rotates synchronously with the knob's rotating component.

[0018] Furthermore, the controller records the voltage compensation amount, verification error value, pressure setting value after compensation, and risk level for each compensation, forming a historical data archive.

[0019] Compared with the prior art, the beneficial effects of the present invention are that, by constructing a pressure-angle-voltage signal mapping table, actively applying standard test pressure for deviation detection, and combining working modes for multi-level risk assessment, the present invention forms a complete risk management system of "active diagnosis - automatic compensation - closed-loop verification - intelligent early warning". This effectively solves the technical problems of the prior art, such as the inability to verify the consistency between knob indication and circuit pressure, the inability to actively diagnose mechanical degradation, the inability to automatically compensate for deviations, and the inability to associate working modes for risk early warning.

[0020] Furthermore, this invention actively applies standard test pressure at abnormal points, detects the deviation between the actual voltage signal value and the standard value, and automatically adjusts the knob position based on the deviation to ensure that the compensated pressure setting value is consistent with the actual circuit pressure. Simultaneously, the magnitude and direction of the voltage compensation amount can quantitatively determine the mechanical condition: a positive value increasing with pressure indicates spring fatigue, a negative value increasing with pressure indicates valve core jamming, and significant values ​​within a specific range indicate localized mechanical wear, thus achieving early warning of degradation.

[0021] Furthermore, the present invention obtains the working mode of the anesthesia machine and performs multi-level risk assessment in combination with the compensated pressure setting value: when the pressure is non-zero in mechanical ventilation or standby mode, a zeroing prompt is issued; when the pressure exceeds the limit in manual ventilation mode and the anesthesia machine circuit pressure sensor detects that the circuit pressure is continuously and gradually increasing, the electronically controlled pressure relief valve is activated to actively relieve pressure, thereby avoiding safety hazards during mode switching.

[0022] Furthermore, this invention employs a ring-shaped indicator light surrounding the knob, providing multi-level indication based on the pressure value: off at zero, white with a gradual brightness transition in the first interval, yellow with a gradual brightness transition in the second interval, and red with a gradual brightness transition in the third interval. This allows the operator to intuitively understand the current pressure setting without needing to consult the display screen. Simultaneously, after compensation is completed, a verification pressure is applied. Only if the verification error is within acceptable limits is the compensation considered successful; otherwise, a maintenance alarm is issued and compensation data is output, ensuring the effectiveness of the compensation.

[0023] Furthermore, this invention records the voltage compensation amount, verification error value, post-compensation pressure setpoint, and risk level for each compensation through a controller, forming a historical data archive for maintenance personnel to review and analyze, providing support for preventative maintenance. Simultaneously, the use of a ring-shaped multipole magnet in conjunction with multiple evenly distributed ring-shaped Hall sensors enables non-contact, high-precision angle detection, avoiding the contact wear problems of traditional potentiometer solutions and improving long-term reliability.

[0024] Furthermore, this invention also provides a mechanical scale calibration scheme. When the pressure error is large and frequent electronic compensation is required, the scale markings are adjusted by a movable lever, and the initial pressure markings in the data table are updated, so that the physical scale on the knob is re-aligned with the actual pressure value. This calibration scheme is compatible and complementary to the electronic compensation scheme, which can significantly reduce the frequency and amount of electronic compensation, improve the response speed and stability of the APL valve, and extend the service life of the stepper motor and transmission mechanism. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the APL valve of the anesthesia machine according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the magnetic induction array layout of the APL valve of the anesthesia machine according to an embodiment of the present invention; Figure 3 This is a flowchart of a risk management method for the APL valve of an anesthesia machine according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the pressure indication of the annular indicator light on the APL valve of the anesthesia machine according to an embodiment of the present invention; In the diagram, 10 is a knob, 11 is a magnetic component, 20 is a valve body, 30 is a magnetic induction array, 31 is a Hall sensor, and 40 is a ring indicator light. Detailed Implementation

[0026] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0027] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0029] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] It should be noted that the pressure-angle correspondence in this embodiment is a linear example, and the division of pressure ranges (0-5, 5-10, 10-20 cmH2O) is merely illustrative. In practical applications, the pressure-angle relationship can be piecewise non-linear based on the mechanical characteristics of the APL valve, and the pressure ranges can be flexibly set according to clinical needs, not limited to the calibration points in the mapping table. For example, the first pressure range can be set to 0-8 cmH2O, the second pressure range to 8-15 cmH2O, and the third pressure range to 15-30 cmH2O, or customized according to the patient's condition. Those skilled in the art should understand that as long as a one-to-one correspondence between pressure and angle can be established, and different pressure ranges can be distinguished by the color and brightness of the ring indicator light, it does not depart from the protection scope of this invention.

[0031] Example 1: Please see Figure 1 As shown, it is a structural schematic diagram of the APL valve of an anesthesia machine according to an embodiment of the present invention. This embodiment provides an APL valve for an anesthesia machine, including a knob 10, a valve body 20, a magnetic induction array 30, a stepper motor, a pressure sensor, a pressure control unit, a ring indicator light 40, an electrically controlled pressure relief valve, and a controller.

[0032] The rotating part of the knob 10 is equipped with a magnetic element 11, which is a ring-shaped multipole magnet with 8 pairs of magnetic poles (16 magnetic poles) arranged alternately along the circumference. The valve body 20 is equipped with a magnetic induction array 30, which includes multiple Hall sensors evenly distributed in a ring. It is understood that the number of Hall sensors in the magnetic induction array can be selected based on detection accuracy and cost requirements. A higher number of Hall sensors results in higher angle detection accuracy, but also increases cost. Using two Hall sensors enables basic angle detection, but differential operations cannot eliminate common-mode interference. Using three Hall sensors enables three-phase signal processing, improving accuracy. Using four Hall sensors allows for the elimination of common-mode interference and temperature drift through differential operations, achieving the highest detection accuracy. Considering detection accuracy, anti-interference capability, and cost, this embodiment preferably uses four Hall sensors 31 evenly distributed in a ring, with an angle of 90° between adjacent Hall sensors. However, the present invention is not limited to this. In other embodiments, three, six or eight Hall sensors may be used, as long as they are evenly distributed in a ring and can detect the rotation angle of the knob.

[0033] The annular multipole magnet 11 is coaxially arranged with the knob 10 and rotates synchronously with the knob 10. Four Hall sensors 31 are fixedly mounted on the circuit board, maintaining a non-contact air gap of 1mm to 3mm with the annular multipole magnet 11.

[0034] The stepper motor is connected to the knob 10 and is used to drive the knob 10 to rotate. The stepper motor has a step angle of 1.8°, and a rotational accuracy of 0.1° can be achieved through microstepping.

[0035] The pressure sensor is installed in the breathing circuit of the anesthesia machine to measure the real-time pressure value of the circuit. The pressure sensor is a high-precision diffused silicon pressure sensor with a measurement range of 0–75 cmH2O, an accuracy of ±0.5 cmH2O, and a sampling frequency of 1000 Hz.

[0036] The pressure control unit is used to apply a standard test pressure to the breathing circuit. The pressure control unit includes a gas source and a proportional valve, and can output any set pressure within the range of 0 to 75 cmH2O according to the controller's instructions, with a response time of less than 0.1 seconds.

[0037] The ring indicator light 40 surrounds the knob 10 and consists of 48 RGB LED beads arranged in a uniform ring to emit light signals of different colors and brightness.

[0038] The electrically controlled pressure relief valve is connected in parallel with the APL valve in the breathing circuit. When it receives a command from the controller, it can be opened quickly to actively relieve pressure, with a response time of less than 0.05 seconds.

[0039] The controller is electrically connected to the magnetic induction array 30, stepper motor, pressure sensor, pressure control unit, ring indicator light 40, and electrically controlled pressure relief valve. The controller uses an ARM Cortex-M4 core microcontroller with a main frequency of 168MHz, and has 512KB Flash and 192KB RAM built-in to execute risk management methods.

[0040] It should be noted that, Figure 1 To clearly illustrate the internal structure of the APL valve, only the reference numerals for the main components are shown in the accompanying drawings. The structure and connections of the following components will be clear to those skilled in the art: The valve body 20 includes, but is not limited to, internal mechanical components such as valve cores and springs, for achieving pressure limiting functions; The stepper motor is connected to the knob 10 via a coupling and is mounted on the valve body 20; The pressure sensor is installed in the breathing circuit and connected to the controller via a signal line; The pressure control unit is connected to the breathing circuit via tubing and to the controller via control lines; A ring indicator light 40 surrounds the knob 10 and is connected to the controller via a control line. The electrically controlled pressure relief valve and the APL valve are connected in parallel in the breathing circuit and connected to the controller via a control line; The controller is installed inside the anesthesia machine's main unit and is electrically connected to each component via signal lines.

[0041] The specific structure and connection method of the above-mentioned components are common knowledge in this field and will not be described in detail here.

[0042] It is understood that the pressure control identification involved in the risk management method of the APL valve of the anesthesia machine in this embodiment is simulated using the breathing circuit and the corresponding controllable gas source, which is in a test environment rather than a working environment.

[0043] Please see Figure 2 The diagram shows the layout of the magnetic induction array of the APL valve in an anesthesia machine according to an embodiment of the present invention. In this embodiment, four Hall sensors 31 are evenly distributed in a ring, and the ring-shaped multipole magnet 11 is coaxially arranged with the knob 10. When the knob 10 is rotated, the magnetic field of the ring-shaped multipole magnet 11 rotates accordingly, and the voltage signals output by the four Hall sensors 31 change sinusoidally, satisfying the following relationship:

[0044]

[0045]

[0046]

[0047] Where V1, V2, V3, and V4 are the voltage signals (V) output by the four Hall sensors, A is the signal amplitude (V), and θ is the rotation angle of the knob, which is also the sensing position of the magnetic component, expressed in degrees. The controller calculates the knob rotation angle using the following differential formula: , , , Where Vsin is the sinusoidal component signal after differential processing, and Vcos is the cosine component signal after differential processing; The differential formula can eliminate common-mode interference and temperature drift, improving angle detection accuracy. Experimental verification shows that the angle detection accuracy can reach ±0.3°, corresponding to a pressure detection accuracy of ±0.5 cmH2O.

[0048] Please see Figure 3 and Figure 4 The diagrams shown are a flowchart of the risk management method for the APL valve of an anesthesia machine according to an embodiment of the present invention, and a schematic diagram of the pressure indication of the annular indicator light of the APL valve of an anesthesia machine according to an embodiment of the present invention. The risk management method for the APL valve of an anesthesia machine according to this embodiment includes: Step S1: Obtain the calibration point information of the knob of the APL valve of the anesthesia machine, and set a magnetic component on the knob of the APL valve of the anesthesia machine and set a magnetic induction array on the valve body to collect the voltage signal value output by the magnetic induction array during the rotation of the magnetic component with the knob. Step S2: Control the stepper motor to drive the knob to rotate to the corresponding calibration point, apply the calibration pressure corresponding to the calibration information at each calibration point, and collect the voltage signal value output by the magnetic induction array when the APL valve starts to depressurize, so as to determine the theoretical pressure setting value, knob rotation angle, voltage signal value and standard delay time corresponding to each calibration point, and construct a pressure-angle-voltage signal mapping table. Specifically, the controller controls the stepper motor to drive the knob 10 to rotate sequentially to multiple calibration points. In this embodiment, the calibration points include a zero point, four commonly used pressure points, and a maximum pressure point, for a total of six calibration points. In practice, the commonly used pressure points can be freely selected as needed. Each calibration point corresponds to a factory-set theoretical pressure value for the APL valve and a knob rotation angle. The knob rotation angle is determined by the number of steps the stepper motor takes; for every step the stepper motor rotates, the knob rotates 0.1°.

[0049] At each calibration point, the controller directs the pressure control unit to apply the known calibration pressure corresponding to that point to the breathing circuit, including the zero point (0 cmH2O), 5 cmH2O, 10 cmH2O, 20 cmH2O, 30 cmH2O, 50 cmH2O, and the maximum pressure point (75 cmH2O). The controller outputs an analog voltage signal to the pressure control unit via a digital-to-analog converter interface; this voltage value is proportional to the target pressure. The pressure control unit adjusts the proportional valve opening according to this voltage signal to generate the target pressure in the breathing circuit. The controller monitors the circuit pressure in real time via a pressure sensor, and begins acquiring the voltage signal when the circuit pressure reaches the target value and stabilizes.

[0050] It is understandable that "calibration pressure" refers to the known fixed pressure applied at each calibration point during the initial calibration phase. The pressure value is determined by the calibration point, such as the zero point (0cmH2O), 5cmH2O, 10cmH2O, 20cmH2O, 30cmH2O, 50cmH2O, and the maximum pressure point (75cmH2O). This calibration pressure is used to establish a pressure-angle-voltage signal mapping table, which serves as a benchmark for subsequent real-time monitoring and deviation judgment.

[0051] During the application of standard pressure, the controller continuously acquires the voltage signal values ​​output by four Hall sensors 31 via the magnetic induction array 30. The criterion for the APL valve to begin depressurization is as follows: when the circuit pressure reaches the set value, the valve core is pushed open, and the rate of increase in circuit pressure changes abruptly. The controller identifies the abrupt change point by detecting the first derivative of the pressure signal. The formula for calculating the first derivative of the pressure signal is: , Wherein, Δt is the sampling interval, and in this embodiment, Δt = 0.001 seconds (sampling frequency 1000Hz). When dP / dt exceeds the preset threshold (set to 0.5cmH2O / s in this embodiment), it is determined that pressure relief has begun. The controller records the voltage signal values ​​of the four Hall sensors at this time and takes the average value as the standard voltage signal value of that pressure point.

[0052] The controller records the theoretical pressure setpoint Pi, knob rotation angle θi, and standard voltage signal value Vi corresponding to each calibration point, forming a pressure-angle-voltage signal mapping table. This mapping table is stored in the controller's Flash memory. The format is shown in Table 1 below: Table 1 Pressure-Angle-Voltage Signal Mapping Table

[0053] Step S3: Continuously collect real-time magnetic field distribution data generated when the knob is rotated by the magnetic induction array; obtain the corresponding theoretical pressure setting value based on the pressure-angle-voltage signal mapping table; and simultaneously collect the real-time circuit pressure value measured by the pressure sensor in the breathing circuit of the anesthesia machine. Step S4: Calculate the pressure error between the theoretical pressure setpoint and the real-time pressure value of the circuit to identify abnormal points in each calibration point of the knob; Specifically, by simulating the operation of an anesthesia machine, the controller continuously collects real-time magnetic field distribution data generated when the knob 10 is rotated via the magnetic induction array 30. In this embodiment, the real-time voltage signals output by the four Hall sensors 31 are converted into digital quantities by a 12-bit analog-to-digital converter at a conversion speed of 1000 times per second. The reference voltage of the analog-to-digital converter is 3.3V, and the 12-bit resolution corresponds to a digital quantity of 0-4095, with a voltage resolution of 3.3V / 4096≈0.8mV. After each conversion, the controller stores the voltage value in a circular queue of the RAM buffer.

[0054] The controller calculates the current knob rotation angle using a differential formula based on the real-time voltage signals from four Hall effect sensors. The calculation process is as follows: First, the voltage values ​​V1, V2, V3, and V4 of the four Hall sensors are read. In this embodiment, in a certain sampling, V1 = 2.52V, V2 = 2.48V, V3 = 2.48V, and V4 = 2.52V; Next, calculate the difference: Vsin=V1-V3=2.52V-2.48V=0.04V, Vcos=V2-V4=2.48V-2.52V=-0.04V, Then, the quadrant in which the angle lies is determined based on the signs of Vsin and Vcos. In this embodiment, Vsin > 0, Vcos < 0, and the angle lies in the second quadrant.

[0055] Finally, calculate the arctangent value: θc=arctan(Vsin / Vcos)=arctan(0.04 / -0.04)=arctan(-1)=-45° The angle in the second quadrant is 135°; Based on the current knob rotation angle θc=135°, the controller queries the pressure-angle-voltage signal mapping table constructed in step S1.

[0056] θc = 135° falls between 120° and 175°, corresponding to theoretical pressures of 10 cmH2O and 20 cmH2O, respectively. The controller uses linear interpolation to obtain the corresponding theoretical pressure setpoint Pt. , Where θc represents the knob rotation angle (°) calculated by the controller through the Hall sensor at the current moment, θ1 and θ2 represent the knob rotation angle (°) corresponding to the two calibration points adjacent to θc in the pressure-angle-voltage signal mapping table, and P1 and P2 represent the theoretical pressure setpoint (cmH2O) corresponding to θ1 and θ2 in the pressure-angle-voltage signal mapping table, where P1 corresponds to θ1 and P2 corresponds to θ2.

[0057] In this embodiment, θc = 135°, and in the mapping table, θ1 = 120°, θ2 = 175°, P1 = 10cmH2O, and P2 = 20cmH2O. Substituting into the formula, we get: Pt = 12.73cmH2O, which means that when the knob is rotated to the 135° position, the theoretical pressure setting value is 12.73cmH2O.

[0058] Simultaneously, the controller synchronously acquires the real-time pressure value of the breathing circuit in the anesthesia machine via a pressure sensor. In this embodiment, the pressure sensor outputs a 4-20mA current signal, which is converted into a 1-5V voltage signal by a sampling resistor. The analog-to-digital converter reads a digital value of 1454, with 1024 corresponding to the zero point (0cmH2O) and 4095 corresponding to the full scale (75cmH2O). The controller converts the digital value into a pressure value using a linear transformation formula: , Among them, P a This represents the real-time pressure value (cmH2O) of the circuit acquired by the pressure sensor, ADC v This represents the dimensionless digital value read by the analog-to-digital converter (ADC), ranging from 0 to 4095 (12-bit resolution); o This represents the digital value of the analog-to-digital converter corresponding to the zero point. In this embodiment, the digital value corresponding to the zero point (0cmH2O) is 1024; P s This represents the pressure value (cmH2O) / digital value corresponding to a unit digital quantity. In this embodiment, the digital value corresponding to the full-scale range of 75cmH2O is 4095-1024=3071, therefore P s =75 / 3071≈0.0244cmH2O / digital quantity. Substituting, we get: P a ≈10.5cmH2O.

[0059] At this point, the controller obtains the theoretical pressure setpoint Pt = 12.73 cmH2O, and the real-time loop pressure value P a =10.5cmH2O.

[0060] The controller calculates the theoretical pressure setpoint Pt and the real-time loop pressure value P. aPressure error ΔP: ΔP=|Pt-P a | In this embodiment, the preset error threshold is set to 2 cmH2O. When ΔP exceeds 2 cmH2O, the controller identifies the current knob position as an abnormal point and records the theoretical pressure setting value Pt, the knob angle θc, and the pressure error ΔP at the abnormal point.

[0061] In this embodiment, Pt = 12.73 cmH2O, P a =10.5cmH2O, then: ΔP = |12.73 - 10.5| = 2.23 cmH₂O Since 2.23cmH2O > 2cmH2O, the controller determines that the current knob position (θc = 135°) is an abnormal point and records Pt = 12.73cmH2O, θc = 135°, and ΔP = 2.23cmH2O.

[0062] It is understandable that the preset error threshold can be set according to the accuracy requirements of the corresponding actual application scenario, which will not be elaborated here.

[0063] Step S5: Determine the standard test pressure based on the absolute value of the pressure error, actively apply the standard test pressure to the abnormal point, and obtain the actual voltage signal value output by the magnetic induction array during the application process; Specifically, after identifying an anomaly, the controller determines the standard test pressure Pr based on the absolute value of the pressure error. In this embodiment, the standard test pressure is proportional to the absolute value of the pressure error, with a proportionality coefficient set to 1, i.e., Pr = ΔP = 2.23 cmH2O. The controller outputs an analog voltage signal corresponding to 2.23 cmH2O to the pressure control unit via a digital-to-analog converter interface. The proportional valve in the pressure control unit adjusts its opening according to this voltage signal, generating a test pressure of 2.23 cmH2O in the breathing circuit and maintaining it stable for 0.5 seconds.

[0064] During the application process, the controller continuously acquires the real-time pressure value of the loop through a pressure sensor at a sampling frequency of 1000Hz. The controller calculates the first derivative of the pressure signal, dP / dt, in real time using the following formula: dP / dt=(P(t)-P(t-Δt)) / Δt, The sampling interval Δt = 0.001 seconds. When dP / dt is lower than the preset mutation threshold (in this embodiment, the preset mutation threshold is set to 0.5 cmH2O / s), the APL valve is determined to start depressurizing. At this time, the knob position remains fixed, and the voltage signal output by the magnetic induction array 30 is a stable value. The controller records the voltage signal values ​​output by the four Hall sensors 31 at this moment. To improve detection reliability, the controller continuously records the voltage values ​​corresponding to three depressurization events and takes the average value as the actual voltage signal value Va.

[0065] Step S6: Calculate the difference between the actual voltage signal value and the standard voltage signal value in the mapping table as the voltage compensation amount. When the pressure setting value is zero and the loop pressure exceeds the zero threshold, the voltage compensation amount includes the zero-point compensation amount. Step S7: Adjust the knob position according to the voltage compensation amount to obtain the compensated pressure setting value; Specifically, in this embodiment, after applying a test pressure of 2.23 cmH2O, the APL valve was detected to begin depressurization. The voltage values ​​of the four Hall sensors were: V1 = 2.543V, V2 = 2.542V, V3 = 2.543V, and V4 = 2.542V. The controller calculated the average of the four voltage values, obtaining an actual voltage signal value Va ≈ 2543mV. The controller calculated the difference between the actual voltage signal value Va and the standard voltage signal value Vs at the corresponding pressure in the mapping table, as the voltage compensation amount ΔV. ΔV = Va - Vs, Vs can be obtained by looking up the mapping table. Since the theoretical pressure setpoint Pt=12.73cmH2O at the abnormal point is not a calibration point, the corresponding standard voltage signal value Vs needs to be calculated by interpolation in the mapping table.

[0066] According to the mapping table, P1=10cmH2O corresponds to V1=2540mV, and P2=20cmH2O corresponds to V2=2560mV. Substituting into the linear interpolation formula, we get: Vs=2545mV. Therefore: ΔV = 2543 - 2545 = -2mV, The controller adjusts the knob position based on the voltage compensation amount ΔV. Since there is a definite functional relationship between the voltage signal and the knob angle, the controller converts the voltage compensation amount into an angle compensation amount Δθ.

[0067] Based on the voltage-angle relationship between two calibration points near the abnormal point in the mapping table, calculate the voltage change per unit angle. Near Pt = 12.73 cmH₂O, a voltage change of 20 mV corresponds to an angle change of 55°. Therefore, the slope k = 20 mV / 55° ≈ 0.364 mV / °. The angle compensation amount Δθ = -ΔV / k = (2mV) / (0.364mV / °) = 5.5°. The actual voltage is lower than the standard value, causing the valve core to open prematurely. The theoretical pressure setpoint needs to be increased, requiring rotation in the direction of increased pressure. The controller controls the stepper motor to drive knob 10 to rotate 5.5°, adjusting the knob position from 135° to 140.5°. According to the mapping table, the pressure corresponding to 140.5° is calculated to be 13.73 cmH2O. After compensation, the theoretical pressure setting value was adjusted from 12.73 cmH2O to 13.73 cmH2O.

[0068] The controller connects to the anesthesia machine's main control system via a CAN communication interface and sends a working mode request command. The anesthesia machine's main control system returns the current working mode. In this embodiment, the returned working mode is "mechanical ventilation mode." The controller stores the working mode in RAM.

[0069] After compensation is completed, the controller controls the pressure control unit to apply a verification pressure to the breathing circuit. This verification pressure is equal to the compensated pressure setpoint Pc = 13.73 cmH2O. The controller detects the real-time pressure value of the circuit through a pressure sensor, samples it 10 times consecutively, and takes the average value to obtain Pav.

[0070] In this embodiment, the compensated loop pressure stabilizes at 12.86 cmH2O, thus verifying the error: ΔVv=|Pav-Pc|=|12.86-13.73|=0.87cmH2O, In this embodiment, the preset verification threshold is set to 1 cmH2O. Since 0.87 cmH2O < 1 cmH2O, the compensation is deemed successful.

[0071] Step S8: Based on the current working mode of the anesthesia machine and the compensated pressure setting value, a risk assessment is performed to output a risk level, and an active risk warning operation corresponding to the risk level is executed based on the risk level.

[0072] Specifically, the controller performs multi-level risk assessment by combining the current operating mode of the anesthesia machine with the compensated pressure setpoint: The current operating mode is mechanical ventilation mode, and the compensated pressure setpoint Pc = 13.73 cmH2O. Since Pc ≠ 0, the criteria for determining the first risk level are met, therefore it is determined to be at the first risk level.

[0073] Once the risk level is determined to be Level 1, the controller activates the ring indicator light to emit a zeroing signal. The zeroing signal is set to a slow-flashing yellow light with a flashing frequency of 1Hz and a duty cycle of 50%.

[0074] Meanwhile, the controller sends a zeroing prompt message to the anesthesia machine's main control system via the CAN communication interface. The anesthesia machine's main control system displays the text "Please zero the APL valve before switching modes" on the display screen, reminding the operator to zero the APL valve before switching to manual ventilation mode.

[0075] During a risk warning period, the ring indicator light 40 displays a zero-reset signal (slow yellow flashing) and does not perform pressure indication. Once the risk is cleared, the operator adjusts the knob to the zero position, and the controller turns off the ring indicator light 40 according to the compensated pressure setpoint Pc=0cmH2O.

[0076] The controller records the relevant data for this compensation in the Flash memory, forming a historical data archive.

[0077] Example 2: Unlike Example 1, in this example, the anesthesia machine is in manual ventilation mode, and the compensated pressure setting exceeds the preset safety threshold, and the circuit pressure is detected to continuously rise above the safety threshold.

[0078] Steps S1 to S6 are the same as in Example 1, and will not be repeated here.

[0079] The anesthesia machine's main control system has returned to the current operating mode as "manual ventilation mode".

[0080] After successful compensation, the controller performs multi-level risk assessment based on the anesthesia machine's current operating mode and the compensated pressure setpoint: The current operating mode is manual ventilation mode, with a preset safety threshold set at 15 cmH2O. In this embodiment, the compensated pressure setting value Pc = 20 cmH2O, exceeding the preset safety threshold of 15 cmH2O. Simultaneously, a continuous increase in loop pressure exceeding 15 cmH2O is detected, meeting the criteria for the second risk level. Therefore, it is determined to be at the second risk level. The controller controls the ring indicator 40 to issue a pressure over-limit alarm signal, which is a red flashing light with a flashing frequency of 4Hz and a duty cycle of 50%. It also activates the electrically controlled pressure relief valve for active pressure relief. Simultaneously, the controller sends the pressure over-limit alarm information to the anesthesia machine's main control system via the CAN communication interface. The anesthesia machine's main control system displays the text "Pressure over-limit, pressure relief activated" on the display screen and issues an audible alarm.

[0081] Example 3: Unlike Example 1, in this example, the anesthesia machine is in manual ventilation mode, and the compensated pressure setting is within a safe range and in the first pressure range.

[0082] Steps S1 to S6 are the same as in Example 1, and will not be repeated here.

[0083] The anesthesia machine's main control system returns to the current operating mode as "manual ventilation mode." After successful compensation, the controller performs a multi-level risk assessment based on the anesthesia machine's current operating mode and the compensated pressure setpoint. The current operating mode is manual ventilation mode, and the preset safety threshold is set to 15 cmH2O. In this embodiment, the compensated pressure setting value Pc = 2.5 cmH2O, which does not exceed 15 cmH2O. Therefore, it does not meet the judgment criteria for the second risk level and is judged to be risk-free.

[0084] In this embodiment, there is no risk level, and no proactive risk warning operation is performed. Without a risk warning, the controller controls the ring indicator 40 to emit a corresponding light signal based on the compensated pressure setpoint Pc = 2.5 cmH2O.

[0085] The pressure setting is 2.5 cmH2O, which falls within the first pressure range (0–5 cmH2O). According to the pressure indication rules, the ring indicator 40 emits a white light, with the brightness proportional to the pressure value. The brightness duty cycle is (2.5 / 5) × 100% = 50%. The controller outputs a white light signal to the ring indicator 40 with a 50% duty cycle, indicating that the current pressure setting is 2.5 cmH2O.

[0086] Example 4: Unlike Example 1, in this example the anesthesia machine is in manual ventilation mode, and the compensated pressure setting is within a safe range and in the second pressure zone.

[0087] Steps S1 to S6 are the same as in Example 1, and will not be repeated here. The anesthesia machine's main control system returns to the current operating mode as "manual ventilation mode". After successful compensation, the controller performs a multi-level risk assessment based on the anesthesia machine's current operating mode and the compensated pressure setpoint: The current operating mode is manual ventilation mode, with a preset safety threshold set to 15 cmH2O. In this embodiment, the compensated pressure setting value Pc = 7.5 cmH2O, which does not exceed 15 cmH2O, therefore it does not meet the criteria for the second risk level and is judged as risk-free. In this embodiment, there is no risk level, and no active risk warning operation is performed. In the absence of a risk warning, the controller controls the ring indicator 40 to emit a corresponding light signal based on the compensated pressure setting value Pc = 7.5 cmH2O.

[0088] 7.5 cmH2O falls within the second pressure range (5-10 cmH2O). According to the pressure indication rules, the ring indicator 40 emits a yellow light, and the brightness of the light is proportional to the pressure value. The brightness duty cycle is ((7.5-5) / 5) × 100% = 50%.

[0089] The controller outputs a yellow light signal to the ring indicator 40 with a duty cycle of 50%, indicating that the current pressure setting is 7.5 cmH2O.

[0090] Example 5: Unlike Example 1, in this example the anesthesia machine is in manual ventilation mode, and the compensated pressure setting is within a safe range and in the third pressure zone.

[0091] Steps S1 to S6 are the same as in Example 1, and will not be repeated here. The anesthesia machine's main control system returns to the current operating mode as "manual ventilation mode". After successful compensation, the controller performs a multi-level risk assessment based on the anesthesia machine's current operating mode and the compensated pressure setting: the current operating mode is manual ventilation mode, and the preset safety threshold is set to 15 cmH2O. In this example, the compensated pressure setting Pc = 13 cmH2O, which does not exceed 15 cmH2O, therefore it does not meet the criteria for the second risk level and is judged as risk-free. In this example, there is no risk level, and no active risk warning operation is performed. In the absence of a risk warning, the controller controls the ring indicator 40 to emit a corresponding light signal based on the compensated pressure setting Pc = 13 cmH2O.

[0092] 13 cmH2O falls within the third pressure range (10–20 cmH2O). According to the pressure indication rules, the ring indicator 40 emits a red light, and the light brightness is proportional to the pressure value. The brightness duty cycle is calculated as: Duty = ((13-10) / 10) × 100% = 30%.

[0093] The controller outputs a red light signal to the ring indicator 40 with a duty cycle of 30%, indicating that the current pressure setting is 13cmH2O.

[0094] Example 6: Unlike Example 1, in this example, the knob was adjusted to the zero position, but due to mechanical reasons, there was residual pressure in the circuit. After active compensation, it was successfully returned to zero.

[0095] In this embodiment, the knob is in the zero position, and the theoretical pressure setpoint is Pt = 0 cmH2O. The real-time pressure value P of the circuit is collected by the pressure sensor. a =3.2cmH2O. The pressure error ΔP = 3.2cmH2O > 2cmH2O, so the controller determines the current knob position is an abnormal zero point. Based on the pressure error ΔP = 3.2cmH2O, the controller determines the standard test pressure Pt = 3.2cmH2O and actively applies this test pressure to the breathing circuit.

[0096] The actual voltage signal value Va was detected, and the standard voltage signal value at the zero point was Vs = 2500mV. Va = 2480mV, so the voltage compensation amount ΔV = -20mV.

[0097] The controller adjusts the knob position based on the voltage compensation amount ΔV to obtain the compensated pressure setpoint Pc=0cmH2O. In this embodiment, the anesthesia machine is in standby mode.

[0098] After compensation is completed, the controller applies a verification pressure Pc=0cmH2O, the real-time pressure value of the detection loop Pav=0.2cmH2O, and the verification error ΔVv=0.2cmH2O<1cmH2O, thus the compensation is deemed successful.

[0099] The controller combines the current operating mode of the anesthesia machine with the compensated pressure setpoint to perform multi-level risk assessment: The current operating mode is standby mode. The compensated pressure setpoint Pc = 0 cmH2O, which does not meet the first risk level judgment condition, and is therefore judged as no risk. In this embodiment, there is no risk level, and no active risk warning operation is performed. In the absence of a risk warning, the controller controls the ring indicator light 40 to turn off based on the compensated pressure setpoint Pc = 0 cmH2O.

[0100] Example 7: Unlike Example 1, the verification failed after compensation in this example, and it was not a zero-return anomaly scenario.

[0101] After compensation is complete, the controller directs the pressure control unit to apply a verification pressure to the breathing circuit. This verification pressure is equal to the compensated pressure setpoint Pc. The controller detects the real-time pressure value of the circuit using a pressure sensor and calculates the verification error ΔVv.

[0102] In this embodiment, the circuit pressure still cannot reach the set value after compensation. Pav = 8.5 cmH2O, while Pc = 12.5 cmH2O, so the verification error ΔVv = 4.0 cmH2O > 1 cmH2O, and the compensation is judged to have failed.

[0103] The controller controls the ring indicator light 40 to issue a maintenance alarm signal, which flashes yellow at a frequency of 2Hz and a duty cycle of 50%. It also outputs a voltage compensation amount ΔV=-5mV and a verification error value ΔVv=4.0cmH2O to the main control system of the anesthesia machine through the CAN communication interface.

[0104] Example 8: Mechanical Scale Calibration This embodiment adds an auxiliary mechanical calibration function to the magnetic induction detection + stepper motor automatic compensation scheme described in Embodiments 1 to 7. This scheme is fully compatible with the original technical solutions and aims to reduce the frequency and amount of electronic compensation by mechanically adjusting the scale markings when the pressure error is large and frequent electronic compensation is required, thereby improving the response speed and stability of the APL valve.

[0105] Applicable scenarios: When the system detects the following conditions, it is recommended to enter engineering calibration mode for mechanical scale calibration: The number of times electronic compensation is triggered within a week exceeds the preset threshold (e.g., 10 times); or the absolute value of a single voltage compensation exceeds the preset compensation threshold (e.g., 20mV); or the cumulative compensation continues to increase without convergence.

[0106] Mechanical structure: In this embodiment, the pressure markings on the APL valve knob are configured as movable and lockable lever structures. Each lever corresponds to a pressure marking (e.g., 0, 5, 10, 20, 30, 50, 75 cmH2O), and can slide within the annular groove of the knob, locking itself once the target position is reached.

[0107] In this embodiment, the historical data recorded by the controller shows that the average voltage compensation ΔV corresponding to the 20cmH2O pressure mark point is -2mV, and this compensation has been increasing over the past 3 months, indicating that the mechanical offset has accumulated to the point where physical calibration is required.

[0108] The maintenance personnel entered the engineering calibration mode through the maintenance menu on the anesthesia machine's display screen. The system prompted, "Please confirm that the APL valve is in standby mode." After the maintenance personnel confirmed, the controller began executing the calibration procedure.

[0109] The controller controls the stepper motor to drive the knob to rotate to the compensated position. According to historical data, the voltage compensation amount ΔV corresponding to the 20cmH2O mark is -2mV. After compensation, the knob position is adjusted from 175° to 180.5° (see Example 1 for the calculation process).

[0110] At this point, the knob is in the compensated position (180.5°), and the actual pressure of the APL valve is consistent with the theoretical pressure setting of 20cmH2O.

[0111] The anesthesia machine display shows: "Pressure mark 20: Electronic compensation is complete. The current knob position is 180.5°. Please adjust the lever to the current knob position (180.5°) and lock it after adjustment." Following the instructions, the maintenance personnel manually moved the lever corresponding to the 20cmH2O mark, slid it to the current knob position (180.5°), and locked it.

[0112] After the maintenance personnel confirmed the lockout, the controller updated the pressure-angle-voltage signal mapping table, changing the knob angle corresponding to 20cmH2O from 175° to 180.5°, and updating the standard voltage signal value corresponding to that pressure mark to the currently measured voltage signal value. Simultaneously, the controller cleared the accumulated voltage compensation and restarted recording. This calibration is now complete.

[0113] After the aforementioned mechanical calibration, the physical scale marking at the 20cmH2O point on the knob is realigned with the actual pressure value. Thereafter, under the same operating conditions, this pressure point will no longer trigger electronic compensation, or will only require minimal compensation.

[0114] It is understood that the mechanical calibration scheme described in this embodiment is fully compatible with the electronic compensation schemes described in Embodiments 1 to 8, and the two complement each other: When the electronic compensation frequency and compensation amount are small, the system relies on electronic compensation for real-time correction without the need for manual intervention.

[0115] When the electronic compensation frequency and compensation amount are too large, the system prompts to enter the engineering calibration mode. Through mechanical calibration, the physical offset is fundamentally corrected, the electronic compensation is returned to zero, and the system's fast response and stable control are restored.

[0116] This embodiment achieves the following technical effects: reducing the frequency and amount of electronic compensation, improving the response speed and stability of the APL valve, and extending the service life of the stepper motor and transmission mechanism.

[0117] Comparative example: Performed in accordance with the embodiment section in Chinese Patent Publication No. CN219167406U.

[0118] Compared with the prior art CN219167406U, the present invention has significant advantages in the following performance indicators: Regarding detection accuracy: Existing technologies use gratings and photoelectric switches to detect the knob angle. The angular resolution is limited by the grating line density, typically ±2°, corresponding to a pressure detection accuracy of ±2 cmH2O. This invention uses a ring-shaped multipole magnet in conjunction with four Hall sensors evenly distributed in a ring. By using a differential formula to eliminate common-mode interference and temperature drift, the angle detection accuracy can reach ±0.3°, corresponding to a pressure detection accuracy of ±0.5 cmH2O, representing an improvement in detection accuracy of approximately 6 times.

[0119] Regarding anti-interference capabilities: Existing technologies use optical detection, but the optical window is easily contaminated by dust, blood, and bodily fluids in the operating room environment, leading to a decrease in detection accuracy after long-term use. This invention uses non-contact magnetic induction detection, which is unaffected by optical window contamination, resulting in higher reliability over long-term use.

[0120] In terms of diagnostic capabilities: Existing technologies can only passively detect knob positions and cannot actively detect the health status of APL valves. This invention, when a pressure error exceeds a threshold, actively applies a standard test pressure to the breathing circuit. By quantitatively judging the mechanical condition through the magnitude and direction of voltage compensation, it can detect hidden faults such as spring fatigue, valve core jamming, and transmission wear at an early stage.

[0121] Regarding compensation capabilities: Existing technologies can only issue reminder signals and rely on manual intervention for adjustment. This process is cumbersome, and accuracy depends on the operator's experience, taking an average of 45 seconds to complete. This invention automatically adjusts the knob position based on the voltage compensation amount, applies verification pressure after compensation to form a closed-loop control, and completes compensation in approximately 5 seconds, improving compensation efficiency by 9 times and achieving a compensation accuracy of ±0.5cmH2O.

[0122] Regarding risk warning: Existing technologies only issue warning signals based on the knob position, without considering the anesthesia machine's operating mode, and cannot identify the hidden risk of "non-zero pressure in mechanical ventilation mode". This invention obtains the current operating mode of the anesthesia machine and performs multi-level risk assessment based on the compensated pressure setpoint. When the pressure is non-zero in mechanical ventilation or standby mode, a zeroing prompt is issued. When the pressure exceeds the limit in manual ventilation mode, the electronically controlled pressure relief valve is activated to actively relieve pressure, effectively avoiding the risk of barotrauma during mode switching.

[0123] Regarding ease of operation: Existing technologies emit a single-color light through a light-transmitting cover, which can only indicate the pressure range; operators still need to check the display screen to understand the specific pressure value. This invention uses a ring-shaped indicator light surrounding the knob, which intuitively displays the pressure value through color partitioning and gradual brightness changes, improving operational efficiency by 50%. In emergency situations, the pressure status can be confirmed without shifting the operator's gaze.

[0124] Regarding data traceability: Existing technologies lack data recording capabilities and cannot trace the performance degradation history of APL valves. This invention records the voltage compensation amount, verification error value, post-compensation pressure setpoint, and risk level for each compensation, forming a historical data archive. This supports performance degradation trend analysis and preventative maintenance, allowing for advance maintenance planning to avoid sudden failures.

[0125] Experimental data show that the present invention is significantly superior to the prior art in key performance indicators such as detection accuracy, diagnostic capability, compensation efficiency, safety warning, ease of operation and data traceability, and can effectively solve technical problems such as mechanical degradation, pressure deviation and mode switching risk in the long-term use of APL valves.

[0126] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A risk management method for an anesthesia machine's APL valve, characterized in that, include: Step S1: Obtain the calibration point information of the knob of the APL valve of the anesthesia machine, and set a magnetic component on the knob of the APL valve of the anesthesia machine and set a magnetic induction array on the valve body to collect the voltage signal value output by the magnetic induction array during the rotation of the magnetic component with the knob. Step S2: Control the stepper motor to drive the knob to rotate to the corresponding calibration point, apply the calibration pressure corresponding to the calibration information at each calibration point, and collect the voltage signal value output by the magnetic induction array when the APL valve starts to depressurize, so as to determine the theoretical pressure setting value, knob rotation angle, voltage signal value and standard delay time corresponding to each calibration point, and construct a pressure-angle-voltage signal mapping table. Step S3: Continuously collect real-time magnetic field distribution data generated when the knob is rotated by the magnetic induction array; obtain the corresponding theoretical pressure setting value based on the pressure-angle-voltage signal mapping table; and simultaneously collect the real-time circuit pressure value measured by the pressure sensor in the breathing circuit of the anesthesia machine. Step S4: Calculate the pressure error between the theoretical pressure setpoint and the real-time pressure value of the circuit to identify abnormal points in each calibration point of the knob; Step S5: Determine the standard test pressure based on the absolute value of the pressure error, actively apply the standard test pressure to the abnormal point, and obtain the actual voltage signal value output by the magnetic induction array. Step S6: Calculate the difference between the actual voltage signal value and the standard voltage signal value in the mapping table as the voltage compensation amount. When the pressure setting value is zero and the loop pressure exceeds the zero threshold, the voltage compensation amount includes the zero-point compensation amount. Step S7: Adjust the knob position according to the voltage compensation amount to obtain the compensated pressure setting value; Step S8: Based on the current working mode of the anesthesia machine and the compensated pressure setting value, a risk assessment is performed to output a risk level, and an active risk warning operation corresponding to the risk level is executed based on the risk level.

2. The risk management method for the APL valve of an anesthesia machine according to claim 1, characterized in that, Each calibration point in step S1 includes the zero point position, the commonly used pressure point position, and the maximum pressure point position.

3. The risk management method for the APL valve of an anesthesia machine according to claim 1, characterized in that, The standard test pressure mentioned in step S5 is proportional to the absolute value of the pressure error.

4. The risk management method for the APL valve of an anesthesia machine according to claim 1, characterized in that, Step S8 further includes: After compensation is completed, a verification pressure is applied to the breathing circuit to detect the verification error between the real-time pressure value of the circuit and the compensated pressure set value. If the verification error is less than the preset verification threshold, then the risk is determined by combining the current state of the anesthesia machine and the compensated pressure value, and the risk level is output. If the verification error is greater than or equal to the preset verification threshold, the ring indicator light is controlled to issue a maintenance alarm signal, and the voltage compensation amount and the verification error value are output.

5. The risk management method for the APL valve of an anesthesia machine according to claim 4, characterized in that, In step S8, a multi-level risk assessment is performed based on the current operating mode of the anesthesia machine and the compensated pressure setpoint, including: If the current working mode is mechanical ventilation mode or standby mode, and the compensated pressure setting value is not zero, it is determined to be the first risk level; If the current working mode is manual ventilation mode and the compensated pressure setting exceeds the preset safety threshold, it is determined to be the second risk level.

6. The risk management method for the APL valve of an anesthesia machine according to claim 5, characterized in that, If the risk level is determined to be the first level, the control ring indicator light will issue a zeroing prompt signal. If the risk level is determined to be the second level, the control ring indicator light will issue a pressure over-limit alarm signal and activate the electronically controlled pressure relief valve to actively relieve pressure.

7. The risk management method for the APL valve of an anesthesia machine according to claim 6, characterized in that, In the absence of risk warning, the ring indicator light is configured as follows: When the compensated pressure setpoint is zero, the control ring indicator light will turn off. When the compensated pressure setting value is within the first pressure range, the ring indicator light is controlled to emit a first color light, and the brightness of the light is proportional to the value of the compensated pressure setting value within the first pressure range. When the compensated pressure setting value is in the second pressure range, the control ring indicator light emits a second color light, and the brightness of the light is proportional to the value of the compensated pressure setting value in the second pressure range; When the compensated pressure setting value is in the third pressure range, the control ring indicator light emits a third color light, and the brightness of the light is proportional to the value of the compensated pressure setting value in the third pressure range.

8. An APL valve for an anesthesia machine, used to perform the risk management method for the APL valve of an anesthesia machine according to any one of claims 1-7, characterized in that, include: A knob, used to adjust the working pressure value of the APL valve, including a magnetic component on the rotating part of the knob; The valve body is provided with a magnetic induction array, which cooperates with the magnetic component to collect real-time magnetic field distribution data generated when the knob is rotated, so as to obtain the rotation position of the knob. A stepper motor, connected to the knob, is used to drive the knob to rotate; A pressure sensor, which is installed in the breathing circuit of the anesthesia machine, is used to measure the real-time pressure value of the circuit; Pressure control unit, which is used to apply standard test pressure to the breathing circuit; A ring-shaped indicator light, arranged around the knob, is used to emit a light signal; An electrically controlled pressure relief valve is connected in parallel with the APL valve in the breathing circuit; The controller, which is electrically connected to the magnetic induction array, stepper motor, pressure sensor, pressure control unit, ring indicator and electrically controlled pressure relief valve respectively, is used to execute the risk management method of the APL valve of the anesthesia machine according to any one of claims 1-7 based on the acquired data.

9. The APL valve for an anesthesia machine according to claim 8, characterized in that, The magnetic induction array includes several Hall sensors that are uniformly distributed in a ring. The magnetic component is a ring-shaped multipole magnet, which is coaxially arranged with the knob and rotates synchronously with the knob's rotating component.

10. The APL valve for an anesthesia machine according to claim 8 or 9, characterized in that, The controller records the voltage compensation amount, verification error value, pressure set value after compensation, and risk level for each compensation, forming a historical data archive.

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