Systems and methods for induction heated anesthetic agent vaporizers

Abstract

The present invention provides methods and systems for delivering an anesthetic agent to a patient. In one embodiment, an anesthetic agent vaporizer includes: a vaporization chamber configured to hold a liquid anesthetic agent; a grid disposed within the vaporization chamber; and a heating element positioned relative to the vaporization chamber and configured to increase the temperature of the grid.

Description

Technical Field

[0001] Embodiments of the subject matter disclosed herein relate to anesthesia systems, and more particularly to anesthetic agent vaporizers. Background Art

[0002] During some medical procedures such as surgical procedures, the patient can be placed under general anesthesia by administering an anesthetic. In some examples, the anesthetic can be a volatile anesthetic administered to the patient via an anesthetic vaporizer. For example, the anesthetic vaporizer can cause and control the vaporization of a volatile anesthetic from a liquid form. A carrier gas (e.g., a mixture of oxygen and fresh air) can flow into the vaporizer and blend (e.g., mix and converge) with the anesthetic vapor produced by the vaporizer. The amount of the carrier gas flowing into the vaporizer can be adjusted by the operator of the vaporizer (e.g., an anesthesiologist) to adjust the ratio of the carrier gas to the anesthetic in the vaporizer. The mixed gas can then flow to the patient, where these gases can be introduced via, for example, inhalation. The concentration of the anesthetic in the mixed gas can be controlled to ensure that sufficient anesthetic is provided to make the patient comfortable without compromising patient safety. Summary of the invention

[0003] In one embodiment, a system for an anesthesia vaporizer includes a vaporization chamber configured to hold a liquid anesthetic agent, a grid disposed within the vaporization chamber, and a heating element positioned relative to the vaporization chamber and configured to increase the temperature of the grid. In this manner, an anesthesia vaporizer is provided that can accurately deliver anesthetic agents to a patient at low fresh gas flow rates (<1 LPM) and high fresh gas flow rates (i.e., between 10 LPM and 15 LPM) with fast response time and stability without suffering a drop in output concentration.

[0004] It should be understood that the above brief description is provided to introduce in a simplified form selected concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is solely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0006] Figure 1A , Figure 1B and Figure 1C A first front perspective view, a second front perspective view, and a rear perspective view of the anesthesia machine are shown, respectively.

[0007] Figure 2A first exemplary embodiment of an anesthetic agent vaporizer system is schematically illustrated.

[0008] Figure 3 A second exemplary embodiment of an anesthetic agent vaporizer system is schematically illustrated.

[0009] Figure 4A A first cross-sectional view of an induction heating grid housed within a gasification chamber is shown.

[0010] Figure 4B A second cross-sectional view of an induction heating grid housed within a vaporization chamber is shown.

[0011] Figure 5 An agent delivery control loop that may be implemented by a controller of an anesthetic agent vaporizer system is shown.

[0012] Figure 6 A heater control loop that may be implemented by a controller of an anesthetic agent vaporizer system is shown.

[0013] Figure 7 is a flow chart illustrating an exemplary embodiment of a method for controlling an amount of vaporized anesthetic agent delivered to a patient via an anesthetic agent vaporizer system including a heating element.

[0014] Figure 8 is a flow chart illustrating an exemplary embodiment of a method for controlling the output power of a heating element of an anesthetic agent vaporizer system.

[0015] Fig. 9 is a flow chart illustrating an exemplary embodiment of a method for manufacturing a grid configured to be received in a vaporizer chamber of an anesthetic agent vaporizer system.

[0016] FIG. 4A to FIG. 4B Shown approximately to scale. DETAILED DESCRIPTION

[0017] The following description relates to various embodiments of an anesthetic gasifier system that may be included in an anesthesia system. It may be challenging to deliver anesthetic quickly, accurately and energy-efficiently by an anesthetic gasifier system. For example, a conventional anesthetic gasifier system may include a pump, a compressor, a pressurized storage tank, a pressurized secondary chamber and / or a syringe. For example, a pump may deliver a liquid anesthetic from a storage tank to a secondary chamber, wherein the liquid anesthetic is boiled by a heater as a whole to gasify the anesthetic and pressurize the secondary chamber. However, boiling the liquid anesthetic as a whole increases the amount of energy consumed by the anesthetic gasifier system due to the overall thermal mass of the liquid anesthetic, which also causes a slow response to the temperature change of the gasifier. For another example, a wick (cotton or plastic) is used, wherein the liquid anesthetic is absorbed by the wick, and medical gas passes through the wick surface. Reagent evaporates from the wick and is entrained in the gas stream. These systems are common and all suffer from slow response and sagging, because high reagent delivery rates and high medical gas flow rates cannot be maintained.

[0018] Thus, according to embodiments disclosed herein, an induction heating grid may be disposed within a vaporization chamber of an anesthetic vaporizer system to vaporize a liquid anesthetic contained within the vaporization chamber. In some embodiments, a gas (e.g., oxygen and fresh air) may be bubbled through the induction heating grid, but in other embodiments, the gas may not be bubbled through the induction heating grid. Additionally, according to embodiments disclosed herein, the amount of anesthetic vapor output by the anesthetic vaporizer system may be controlled in a closed-loop manner based on an electronic feedback signal to accurately provide a desired amount of anesthesia to a patient.

[0019] The embodiments disclosed herein can provide several advantages. For example, due to the small thermal mass of the induction heating grid and the induction heating (e.g., relative to conduction heating), the embodiments disclosed herein can provide a fast response time compared to bulk boiling. In addition, by bubbling gas into the induction heating grid, the temperature of the bubbles can be increased, thereby increasing the amount of anesthetic agent vaporized inside each bubble and reducing fluctuations. In addition, the induction heating grid can be configured to produce uniform bubbles with an optimal size, thereby further improving the gasification efficiency and further reducing the fluctuations in the amount of vaporized anesthetic agent produced. In addition, a high concentration of anesthetic agent can be maintained at a high flow rate.

[0020] In addition, the embodiments disclosed herein may also provide additional advantages for controlling the amount of anesthetic vapor output by the anesthetic vaporizer system and delivered to the patient. For example, one or more flow control valves may be adjusted to adjust the amount of anesthetic vapor output by the anesthetic vaporizer system, thereby providing control flexibility and allowing fine-tuning of the amount of anesthetic vapor output by the anesthetic vaporizer system. In addition, the heating of the inductively heated grid may be controlled separately from the amount of anesthetic vapor output by the anesthetic vaporizer system, thereby simplifying the control scheme.

[0021] Figures 1A to 1C A view showing an anesthesia machine according to an exemplary embodiment of the present invention is shown. Figure 2 shows that it may be included in Figures 1A to 1C A first embodiment of an anesthetic agent vaporizer system in an anesthesia machine. Figure 3 shows that it may be included in Figures 1A to 1C A second embodiment of an anesthetic agent vaporizer system in an anesthesia machine. Figure 4A and Figure 4B A cross-sectional view of an induction heating grid housed within a vaporization chamber, which may include Figure 2 and Figure 3 in the anesthetic agent vaporizer system and according to Fig. 9 The exemplary method of manufacturing can be used. Figure 6 The exemplary heater control loop shown is based on Figure 8 The amount of vaporized anesthetic produced by the anesthetic system can be determined using Figure 5 An exemplary reagent delivery control circuit and according to Figure 8 An exemplary method for controlling.

[0022] Figures 1A to 1C From the first side perspective ( Figure 1A )、Second side perspective view( Figure 1B ) and rear perspective ( Figure 1C ) shows an anesthesia machine 100. Figures 1A to 1C The anesthesia machine 100 includes a frame 126 supported by casters 124, wherein the movement of the casters can be controlled (e.g., stopped) by one or more locks 7. In some examples, the frame 126 can be formed of a plastic material (e.g., polypropylene). In other examples, the frame 126 can be formed of a different type of material (e.g., a metal such as steel).

[0023] The anesthesia machine 100 also includes a breathing gas module 1, one or more patient monitoring modules (such as a patient monitoring module 2), a side rail 3, a lighting switch 4, an oxygen control 5, a main power indicator 6, an anesthetic agent storage compartment 8, an oxygen purge button 9, a system activation switch 10 (which, in one example, allows gas flow when activated), an integrated suction device 11, a ventilator 12 (described in more detail below), an auxiliary oxygen flow control 13, an anesthetic agent vaporizer 14, an anesthesia display device 15, and a patient monitoring display device 16. Exemplary embodiments of the anesthetic agent vaporizer will be described below with respect to Figure 2 and Figure 3 The anesthetic agent vaporizer 14 may vaporize the anesthetic agent and combine the vaporized anesthetic agent with one or more medical grade gases (eg, oxygen, air, nitrous oxide, or a combination thereof), which may then be delivered to a patient.

[0024] The rear portion of the anesthesia machine 100 is shown in Figure 1C In. At the rear of the anesthesia machine, there are one or more pipe connectors 46 to facilitate the connection of the anesthesia machine to the pipeline gas source. In addition, the rear of the anesthesia machine includes a cylinder bracket 44, and one or more gas holding cylinders can be connected to the anesthesia machine via the cylinder bracket. Therefore, through the pipeline connection and / or cylinder connection, gas can be provided to the anesthesia machine, wherein the gas may include but is not limited to air, oxygen and nitrous oxide. As described above, the gas entering the anesthesia machine can be mixed with the gasified anesthetic at the anesthetic gasifier 14 and supplied to the patient via the ventilator 12. The rear of the anesthesia machine may also include a serial port 41, a collection bottle connector 42, a cylinder wrench storage area 43, an anesthetic gas scavenging system 45, a main power inlet 47, a system circuit breaker 48, an equipotential stud 49, an outlet circuit breaker 50 and an isolation power outlet 51.

[0025] like Figure 1B As shown, the ventilator 12 may include an exhalation check valve 22 at an exhalation port, an inhalation check valve 23 at an inhalation port, an inhalation flow sensor 24, an exhalation flow sensor 25, an absorber 26, an absorber release 27, a leak test plug 28, a manual bag port 29, a ventilator release 30, an adjustable pressure limiting valve 31, a bag / exhaust switch 32, and a bellows assembly 33. When the patient breathing circuit is connected to the ventilator 12, breathing gas (e.g., air, oxygen, and / or nitrous oxide mixed with vaporized anesthetic) leaves the machine from the inhalation port (located at the same position as the inhalation check valve 23) and travels to the patient. The exhalation gas from the patient reenters the anesthesia machine via the exhalation port (located at the same position as the exhalation check valve 22), where carbon dioxide can be removed from the exhalation gas via the absorber 26.

[0026] During operation of the anesthetic agent vaporizer 14, an operator (e.g., an anesthesiologist) can adjust the amount of vaporized anesthetic agent supplied to the patient by adjusting the gas flow rate from the gas source (e.g., a gas line) to the vaporizer. The operator can adjust the gas flow rate from the gas source to the vaporizer by adjusting one or more flow regulating devices. For example, the flow regulating device may include an analog and / or digital adjustment dial and / or other user input device configured to actuate one or more flow control valves of the anesthesia machine 100. In some embodiments, a first flow control valve may be positioned between the gas source and the anesthetic agent vaporizer 14 and may be actuated via the flow regulating device to a fully open position, a fully closed position, and a plurality of positions between the fully open position and the fully closed position. The different flow control valves that can be adjusted to change the amount of vaporized anesthetic agent supplied to the patient will be described below with respect to the following. Figure 2 Further description.

[0027] The anesthesia machine may additionally include one or more valves configured to allow gas from the gas source to bypass the anesthetic agent vaporizer 14. The valves may allow a first portion of gas to flow directly from the gas source to the inspiratory port, and allow a second portion of gas to flow from the gas source through the anesthetic agent vaporizer 14 to mix with the vaporized anesthetic agent before flowing to the inspiratory port. By adjusting the ratio of the first portion of gas to the second portion of gas, the operator can control the concentration of the vaporized anesthetic agent administered to the patient via the inspiratory port.

[0028] In addition, the above-mentioned regulation can be facilitated at least in part based on the output from the breathing gas module 1. The breathing gas module 1 can be configured to measure various parameters of the gas leaving the gasifier and / or provided to the patient. For example, the breathing gas module 1 can measure the concentration of carbon dioxide, nitrous oxide, and anesthetic provided to the patient. In addition, the breathing gas module 1 can measure the respiratory rate, minimum alveolar concentration, patient oxygen, and / or other parameters. The output of the breathing gas module 1 can be displayed on a display device (e.g., anesthesia display device 15 and / or patient monitoring display device 16) via a graphical user interface and / or be used by a controller to provide closed-loop feedback control of the amount of anesthesia provided to the patient.

[0029] The ventilator 12 may optionally be coupled to a breathing circuit (not shown) comprising a plurality of tubes (e.g., gas passages). The breathing circuit may be coupled between the patient's airway (e.g., via a breathing mask positioned to enclose the patient's mouth and / or nose or an endotracheal tube) and an inspiratory port. A gas (e.g., oxygen, or a mixture of oxygen and a vaporized anesthetic from the anesthetic vaporizer 14) may flow from the inspiratory port through the breathing circuit and into the patient's airway, where the gas is absorbed by the patient's lungs. By adjusting the concentration of the vaporized anesthetic in the gas as described above, the operator may adjust the degree of anesthesia of the patient.

[0030] During a state in which the breathing circuit is coupled to the airway, anesthetic agent and / or fresh gas (without anesthetic agent) may flow into the patient's airway (e.g., by inhalation) via the inhalation check valve 23. For example, the inhalation check valve 23 may open automatically (e.g., without operator input or adjustment) in response to the patient's inhalation, and may close automatically in response to the patient's exhalation. Similarly, the exhalation check valve 22 may open automatically in response to the patient's exhalation, and may close automatically in response to the patient's inhalation.

[0031] In some embodiments, the operator may additionally or alternatively control one or more operating parameters of the anesthesia machine 100 via the electronic controller 140 of the anesthesia machine 100. The controller 140 includes a processor operatively connected to a memory. The memory may be a non-transitory computer-readable medium, and may be configured to store computer executable code (e.g., instructions) to be processed by the processor to execute one or more routines (such as those described herein). The memory may also be configured to store data received by the processor. The controller 140 may be communicatively connected (e.g., via a wired or wireless connection) to one or more external or remote computing devices such as a hospital computing system, and may be configured to send and receive various information such as electronic medical record information, procedure information, etc. The controller 140 may also be electrically connected to various other components of the anesthesia machine 100, such as an anesthetic gasifier 14, a ventilator 12, a respiratory gas module 1, an anesthesia display device 15, and a patient monitoring display device 16.

[0032] The controller receives signals from various sensors of the anesthesia machine 100 and uses various actuators of the anesthesia machine 100 to adjust the operation of the anesthesia machine 100 based on the received signals and instructions stored on the memory of the controller. For example, the flow of gas to the inspiratory port can be controlled via an input device (e.g., a keyboard, a touch screen, etc.) connected to the electronic controller of the anesthesia machine 100. The controller 140 can display the operating parameters of the anesthesia machine 100 via the anesthesia display device 15 and / or the patient monitoring display device 16. The controller can receive a signal (e.g., an electrical signal) via the input device, and can adjust the operating parameters of the anesthesia machine 100 in response to (e.g., in response to) the received signal.

[0033] For example, the operator may input a desired concentration of an anesthetic to be delivered to the patient. The corresponding valve position of one or more valves of the anesthesia machine (e.g., the position of one or more bypass valves, as described above) may be determined empirically and stored in a predetermined lookup table or function in a memory of the controller. For example, the controller may receive a desired anesthetic concentration via an input device, and may determine the opening amount of the one or more valves corresponding to the desired anesthetic concentration based on a lookup table, wherein the input is the concentration of the anesthetic and the output is the valve position of the one or more valves. The controller may transmit an electrical signal to an actuator of the one or more valves so as to adjust each of the one or more valves to a corresponding output valve position. In some examples, the controller may compare a desired gas flow rate with a measured gas flow rate (such as measured by an inspiratory flow sensor 24).

[0034] The controller 140 Figure 1A100 for illustrative purposes, and it should be understood that the controller 140 may be located inside the anesthesia machine 100 and therefore may not be visible outside the anesthesia machine 100. In addition, the controller 140 may include multiple devices / modules that may be distributed throughout the anesthesia machine 100. Therefore, the controller 140 may include multiple controllers at various locations within the anesthesia machine 100 and / or outside the anesthesia machine 100, and the multiple controllers are communicatively connected via wired and / or wireless connections.

[0035] Anesthetic agent vaporizers, such as Figure 1A The anesthetic gasifier 14 shown can use various methods to gasify the liquid anesthetic. For example, the anesthetic gasifier can use an upper flow method (wherein the carrier gas flows above the top surface of the volatile liquid anesthetic), a bubbling method (wherein the carrier gas bubbles upward through the liquid anesthetic) or a gas / vapor blender (wherein heat is used to gasify the liquid anesthetic and the vapor is injected into the fresh gas flow). When the anesthetic undergoes a phase change from liquid to vapor, it absorbs energy known as the latent heat of vaporization. Therefore, at least in some examples, even upper flow and bubbling gasifiers can also utilize temperature compensation mechanisms. In the example of a bubbling gasifier, as the size of the bubbles produced decreases, the surface area to volume ratio of the bubbles increases, which helps the gasification of the liquid anesthetic. Current methods of breaking the carrier gas into small bubbles include stirring and spraying. However, such methods may be inefficient and may result in uneven bubble sizes.

[0036] Figure 2 An embodiment of the invention may be included in an anesthesia system (e.g., Figures 1A to 1C The anesthesia system 100 shown in FIG. 1 is a first exemplary embodiment of an anesthetic agent vaporizer system 200 in the anesthesia system 100. For example, the anesthetic agent vaporizer system 200 may be Figure 1A The anesthetic agent vaporizer 14. Specifically, the anesthetic agent vaporizer system 200 is a bubbler anesthetic agent vaporizer, including a vaporization chamber 202 defined by a housing 204 in which a grid 206 is disposed. The grid 206 may be composed of a structurally defined three-dimensional metal mesh, such as a relative FIG. 4A to FIG. 4B As further described, for example, the grid 206 may be 3D printed into a defined geometry, thereby reducing variations from part to part.

[0037] The heating element 208 is positioned outside of the vaporizer chamber 202, such as in direct contact with (e.g., touching) a lower portion of the housing 204. In other embodiments, the heating element 208 may not be in direct contact with the housing 204. In further examples, the heating element 208 may be positioned inside the vaporizer chamber 202 and / or at least partially integrated within the housing 204. The heating element 208 may be heated by induction, such as where the heating element 208 is an induction heating coil. For example, the heating element 208 may selectively heat the grid 206 via induction without becoming hot itself and / or without directly heating additional components of the anesthetic agent vaporizer system 200 (e.g., the housing 204). However, in some embodiments, the heating element 208 may be heated by conduction.

[0038] The lower portion of the vaporization chamber 202 is shown as holding a liquid anesthetic 210, which is supplied from a reservoir 222 via a conduit 214 and a pump 220. The liquid anesthetic 210 can be, for example, isoflurane, sevoflurane, or another liquid anesthetic having similar volatility. The pump 220 can be a positive displacement pump, such as a reciprocating positive displacement pump. The pump 220 can be selectively operated in response to a command signal from a controller 225 to deliver the liquid anesthetic 210 from the reservoir 222 to the vaporization chamber 202, as will be further described below. The controller 225 can be an electronic controller including a processor operatively connected to a memory. The controller 225 can, for example, include Figure 1A The controller 140 (eg, a portion thereof) is shown in or communicatively coupled to the controller. In addition, the pump 220 can disconnect the vaporizing chamber 202 from the sump 222 so that the sump 222 can be refilled while the anesthetic agent vaporizer system 200 is in use.

[0039] The conduit 214 may further include a shutoff valve 218 coupled between the pump 220 and the vaporization chamber 202. For example, the shutoff valve 218 may be a switch valve, wherein the shutoff valve 218 is actuated to an open (e.g., fully open) position that allows the liquid anesthetic agent 210 to flow between the sump 222 and the pump 220 or a closed (e.g., fully closed) position that prevents (e.g., blocks) the liquid anesthetic agent 210 from flowing between the pump 220 and the vaporization chamber 202. For example, the shutoff valve 218 may be actuated between the open position and the closed position in response to a command signal from the controller 225. A liquid return line 215 may be coupled to the conduit 214 between the shutoff valve 218 and the pump 220 to reduce pressure buildup between the shutoff valve 218 and the pump 220, such as when the shutoff valve 218 is closed. For example, excess liquid anesthetic agent 210 provided by the pump 220 may be returned to the sump 222 via the liquid return line 215.

[0040] The conduit 214 may also include a check valve 219 coupled between the shutoff valve 218 and the vaporizer 202. The check valve 219 may be a one-way, spring-loaded check valve that allows the liquid anesthetic agent 210 to flow from the pump 220 to the vaporizer 202 through the open shutoff valve 218 and prevents the liquid anesthetic agent 210 from flowing from the vaporizer 202 to the pump 220. For example, the check valve 219 may automatically open (e.g., without input or adjustment from a controller or operator) to allow the liquid anesthetic agent 210 to flow to the vaporizer 202, and automatically close to prevent the liquid anesthetic agent 210 from flowing back from the vaporizer 210 to the pump 220. Additionally, the liquid return line 215 may include a restriction 217, such as an orifice, to control flow through the liquid return line 215 such that when the shutoff valve 218 is open, the liquid anesthetic agent 210 preferentially flows through the check valve 219 rather than the restriction 217.

[0041] The controller 225 may selectively activate the pump 220 to provide the liquid anesthetic 210 from the reservoir 222 to the vaporization chamber 202 in response to the measurement received from the liquid level sensor 224. For example, the liquid level sensor 224 may be an optical, ultrasonic, capacitive, floating, or pressure-based liquid level sensor configured to measure the level of the liquid anesthetic 210 in the vaporization chamber 202. For example, the controller 225 may be configured to maintain the level of the liquid anesthetic within a threshold range Δh. The threshold range Δh may be defined by a first lower threshold level and a second higher threshold level. The first threshold level may be a predetermined non-zero level of the liquid anesthetic calibrated to maintain a minimum distance between the grid 206 and the surface of the liquid anesthetic 210 to achieve the desired vaporization characteristics. The second threshold level may be a predetermined non-zero level of the liquid anesthetic calibrated to prevent the vaporization chamber 202 from being overfilled with the liquid anesthetic 210 and to minimize the change in the desired vaporization characteristics within the threshold range. For example, the controller 225 may activate the pump 220 in response to the level of the anesthetic agent 210 reaching a first lower threshold level, and deactivate the pump 220 in response to the level of the anesthetic agent 210 reaching a second higher threshold level. For another example, in addition or alternatively, the controller 225 may activate the pump 220 at a duty cycle selected based on the measured level of the liquid anesthetic agent and / or the measured rate of change of the level of the liquid anesthetic agent to maintain a consistent level of the liquid anesthetic agent 210 in the vaporization chamber 202. For example, the controller may input the measured level of the liquid anesthetic agent and / or the rate of change into one or more lookup tables, algorithms, or functions and output the selected duty cycle. The controller 225 may then activate the pump 220 at the selected duty cycle, which may be adjusted as the measured level of the liquid anesthetic agent and / or the rate of change of the measured level changes. For example, as the measured level increases, the duty cycle at which the pump 220 is activated may decrease, and as the measured level decreases, the duty cycle at which the pump 220 is activated may increase. In addition, a positive displacement stepper motor may also be used, wherein each positive displacement step of the pump is equivalent to a specified volume of anesthetic liquid. In this way, the pump can be used to accurately fill the vaporization chamber and prevent overfilling by recording the number of pump steps delivered. The method can also be used to record the volume of anesthetic delivered to the vaporization chamber, which may be valuable for vaporizer run time / maintenance analysis (maintenance measurement), liquid leak detection, accurate determination of the amount of liquid anesthetic remaining and available for delivery, calculation of vaporization efficiency, etc. In addition, in some embodiments, a liquid level switch 213 may be included to prevent the vaporization chamber 202 from being overfilled with liquid anesthetic 210.

[0042] The upper portion of the vaporization chamber 202 (e.g., above the surface of the liquid anesthetic agent 210) holds a vapor, which may be a mixture of the vaporized anesthetic agent and a carrier gas from a fresh gas stream. The fresh gas stream, and therefore the carrier gas, may contain one or more medical grade gases, such as oxygen, air, nitrous oxide, and combinations thereof. The fresh gas stream may be delivered to the patient via one or more gas conduits (e.g., via a Figure 1C The pipe connection 46 shown) and / or one or more gas holding cylinders (e.g., via Figure 1C The cylindrical bracket 44 is provided. Figure 2 As shown, the fresh gas flow can enter the anesthetic agent vaporizer system 200 via the first gas passage 236. A first proportional valve 243 coupled to the first gas passage 236 can be adjusted by the controller 225 to control the amount (or flow rate) of fresh gas flowing through the first gas passage 236. The first proportional valve 243 can be a variable valve, such as a continuously variable valve, which can be adjusted by the controller 225 between a plurality of positions ranging from a fully open position to a fully closed position. For example, as the opening degree of the first proportional valve 243 increases, the amount (e.g., flow rate) of fresh gas flowing through the first gas passage 236 can increase.

[0043] A first mass flow sensor 241 may be coupled to the first gas passage 236 downstream of the first proportional valve 243 to measure the flow rate of the fresh gas flow entering the anesthetic agent vaporizer system 200. For example, the first mass flow sensor 241 may be an ultrasonic flow meter or a calorimetric (thermal) mass flow meter. A pressure regulator 242 coupled to the first gas passage 236 may limit the pressure of the fresh gas downstream of the pressure regulator 242. For example, the pressure regulator 242 may be a pressure reducing valve such that the pressure of the fresh gas flow downstream of the pressure regulator 242 does not exceed the pressure setting value of the pressure regulator.

[0044] The second gas channel 238 branches off from the first gas channel between the first flow sensor 241 and the pressure reducing valve 242 to provide a carrier gas (e.g., a portion of the fresh gas flow to the gasification chamber 202) to the grid 206. For example, the second gas channel 238 may pass through an opening in the housing 204 that may include a gas-tight seal to allow the carrier gas to flow to the grid 206. In addition, the pressure regulator 242 may control the gas pressure within the second gas channel 238. The second gas channel 238 may include one or more valves disposed therein. Figure 2As shown, the second gas passage 238 includes a check valve 248 and a shutoff valve 246. The check valve 248 may be a one-way valve that allows carrier gas to flow from the fresh gas stream to the grid 206 and prevents carrier gas from flowing from the grid 206 to the common gas passage 234. For example, the check valve 248 may automatically open (e.g., without input or adjustment from a controller or operator) to allow carrier gas to flow to the grid 206, and automatically close to prevent gas from flowing to the common gas passage 234. In contrast, the shutoff valve 246 may be an electronically or mechanically actuated valve that operates in response to input from the controller 225 and / or an operator of the anesthetic agent vaporizer system 200 (e.g., an anesthesiologist). For example, the shut-off valve 246 can be an on-off valve, wherein the shut-off valve 246 is actuated to an open (e.g., fully open) position that allows gas to flow through the shut-off valve 246 or a closed (e.g., fully closed) position that prevents (e.g., blocks) gas from flowing through the shut-off valve 246 in response to an appropriate command signal from the controller 225.

[0045] The carrier gas delivered via the second gas channel 238 flows through the grid 206 located near the bottom of the gasification chamber 202 and completely immersed in the liquid anesthetic 210 to form a plurality of bubbles 212. The plurality of bubbles 212 pass through the liquid anesthetic 210 and become saturated with the gasified anesthetic as they rise to the surface of the liquid. The grid 206 increases the interface area between the carrier gas and the liquid anesthetic 210 by reducing the size of the bubble 212, which in turn increases the gasification rate of the liquid anesthetic 210. For example, the bubble 212 can be a fine bubble and / or microbubble. The geometry of the grid 206 can be selected to optimize the gasification efficiency of the liquid anesthetic, which can be affected by the size of the bubble 212 and the vortex of the bubble 212, for example. For example, the size of the bubble 212 can be selected to maximize the surface area of ​​the fresh gas in contact with the liquid anesthetic 210 while reducing the back pressure (e.g., the pressure drop on the grid 206), and produce a defined and uniform gas distribution. For example, the large surface area to volume ratio of each small bubble 212 enables each bubble to be fully saturated with the vapor of the liquid anesthetic agent 210. In addition to bubble size, vaporization of the liquid anesthetic agent is affected by the amount of time the bubble 212 spends in the liquid anesthetic agent 210 (which can be controlled by controlling the level of the liquid anesthetic agent 210 in the vaporization chamber 202, as described above) and the temperature difference between the bubble 212 and the liquid anesthetic agent 210. By activating the heating element 208 to heat the grid 206, the latent heat of vaporization for the phase change from the liquid form to the vapor form of the anesthetic agent can be provided via direct contact with the heating grid 206 while gradually forming each bubble 212. For example, when the desired anesthetic agent flow rate (or concentration) is low, the amount of power provided to the heating element 208 can be low, thereby preventing the latent heat of vaporization from cooling without increasing the temperature of the bubble 212 and / or the liquid anesthetic agent 210. As another example, when the desired anesthetic agent flow rate (or concentration) is high, the amount of power provided to the heating element 208 may be higher to facilitate the generation of additional vapor bubbles, such as by nucleate boiling from the surface of the grid 206. Thus, all of the carrier gas flowing through the vaporization chamber 202 via the heating grid 206 may be fully saturated with vapor from the liquid anesthetic agent 210, even at high fresh gas flow rates (e.g., 10 L / min).

[0046] Vapor (such as a carrier gas saturated with vaporized anesthetic agent) can flow out of the vaporizing chamber 202 via a third gas passage 240 (e.g., a vapor delivery passage). For example, the third gas passage 240 can pass through an opening at or near the top of the housing 204 and form a joint with the first gas passage 236 to fluidly couple the upper portion of the vaporizing chamber 202 with the first gas passage 236. The third gas passage 240 is shown as including a shutoff valve 250 and a second proportional valve 252 within a manifold heater 254. The shutoff valve 250 can be an electronically or mechanically actuated valve that is adjusted in response to input from the controller 225 and / or an operator. For example, the shutoff valve 250 can be an on-off valve, wherein the shutoff valve 250 is actuated to an open (e.g., fully open) position that allows gas to flow through the shutoff valve 250 or a closed (e.g., fully closed) position that prevents (e.g., blocks) gas from flowing through the shutoff valve 250 in response to an appropriate command signal from the controller 225. For example, the shutoff valve 250 can be closed to quickly stop the supply of anesthetic to the patient. The second proportional valve 252 can be a variable valve, such as a continuously variable valve, which can be adjusted by the controller 225 between multiple positions ranging from a fully open position to a fully closed position. For example, as the opening degree of the second proportional valve 252 increases, the amount (e.g., flow rate) of vapor flowing from the vaporization chamber 202 to the first gas channel 236 (e.g., via the third gas channel 240) can increase. Conversely, as the opening degree of the second proportional valve 252 decreases, the amount of vapor delivered from the vaporization chamber 202 to the first gas channel 236 can decrease. The manifold heater 254 can heat the shutoff valve 250 and the second proportional valve 252 to prevent the vaporized anesthetic from condensing in the valve. As a non-limiting example, the manifold heater 254 can be operated to keep the shutoff valve 250 and the second proportional valve 252 at a substantially constant temperature, such as 40°C.

[0047] Upstream of the junction with the third gas channel 240, the first gas channel 236 carries a portion of the fresh gas flow referred to as bypass gas. The bypass gas does not pass through the vaporizer chamber 202. The amount of bypass gas flowing through the first gas channel 236 can be adjusted by adjusting the fresh gas flow rate and can be limited by the pressure regulator 242. The bypass gas (not containing the vaporized anesthetic agent) and the vapor from the vaporizer chamber 202 (containing the carrier gas saturated with the vaporized anesthetic agent) mix at the junction between the first gas channel 236 and the third gas channel 240 and downstream. This mixed gas can then be passed through the inspiratory branch of the breathing circuit (e.g., via a flow path relative to the inspiratory branch of the breathing circuit). Figure 1BThe second mass flow sensor 244 may be coupled to the first gas channel 236 downstream of the junction with the third gas channel 240 to measure the flow rate of the mixed gas leaving the anesthetic gasifier system 200. For example, the second mass flow sensor 244 may be an ultrasonic flow meter or a calorimetric (thermal) mass flow meter. With respect to the ultrasonic flow metering architecture, the output anesthetic concentration may be calculated by the difference in the time of flight (TOF) between the measured upstream ultrasonic flow sensor 241 and the downstream ultrasonic flow sensor 244. In addition, an independent concentration sensor 256 may be coupled to the first gas channel 236 downstream of the junction with the third gas channel 240. The concentration sensor 256 may be any suitable sensor configured to measure the concentration of the anesthetic agent in the mixed gas. In one example, the concentration sensor 256 may be an optical sensor that transmits light of a suitable wavelength (e.g., infrared) through the mixed gas and determines the concentration of the anesthetic agent based on the absorption of the light by the mixed gas. In other examples, the concentration sensor can be a carbon dioxide or oxygen sensor that measures the concentration of the anesthetic agent based on the displacement of carbon dioxide or oxygen relative to the supply concentration of carbon dioxide or oxygen in the fresh gas flow. The concentration sensor 256 can output a signal indicating the measured anesthetic agent concentration (e.g., the concentration of anesthetic agent vapor) in the mixed gas to the controller 225.

[0048] In addition to receiving signals output by the liquid level sensor 224, the concentration sensor 256, the first mass flow sensor 241, and the second mass flow sensor 224, the controller 225 may also receive additional signals, including: a measured level of the liquid anesthetic agent 210 in the storage tank 222 from the liquid level sensor 221, which may be, for example, an infrared liquid level sensor; a measured vapor pressure (Pgas) inside the vaporizer 202 from a pressure sensor 230 coupled to the upper portion of the vaporizer 202; a measured fresh gas flow pressure (P1) from a pressure sensor coupled to the second gas passage 238 upstream of the check valve 248; a measured vapor temperature (Tm) inside the vaporizer 202 from a temperature sensor 232 coupled to the upper portion of the vaporizer 202 气体 ); the measured temperature of the grid 206 from the temperature sensor 228 coupled to the grid 206 (T 栅格 ); and the temperature (T of the liquid anesthetic 210 measured by the temperature sensor 229 immersed in the liquid anesthetic 液体 ). The controller 225 receives the Figure 2 various sensor signals, process the input data, and use Figure 2The various actuators of the controller 225 adjust the operation of the anesthetic agent vaporizer system 200 based on the received signals and the instructions stored on the memory of the controller. For example, the controller 225 may receive the measured anesthetic agent concentration from the concentration sensor 256 and adjust the position of one or more of the first proportional valve 243 and the second proportional valve 252, as described below with respect to Figure 7 As further described. For example, the controller 225 may receive T from the temperature sensor 228. 栅格 , T from the temperature sensor 229 液体 and the current or voltage supplied to the heating element 208 based on the input measurement results, as described below with respect to Figure 8 Further described.

[0049] Additionally, data may be input to the controller 225 by an operator of the anesthetic agent vaporizer system 200 via a user input device 226 that is operatively connected to the controller and thus configured to transmit input signals to the controller 225 (e.g., via wired or wireless communication). The user input device 226 may include one or more of a mouse, a keyboard, a voice input device, a touch input device for receiving gestures from an operator, a motion input device for detecting non-touch gestures and other actions of an operator, and other similar input devices, as well as associated processing elements capable of receiving user input from an operator.

[0050] Additionally, the controller 225 may calculate the concentration of the anesthetic agent output by the anesthetic agent vaporizer system 200 and delivered to the patient according to the following formula:

[0051]

[0052] Wherein agent % is the percentage concentration of anesthetic agent in the inspiratory branch of the breathing circuit, Fv is the measured flow rate of gas through the vaporizer (in mL / min, such as measured by the second mass flow sensor 244), Ft is the total fresh gas flow entering the vaporizer (in L / min, such as measured by the first mass flow sensor 241), VPa is the vapor pressure of the volatile anesthetic agent (in mmHg), and Pb is the barometric (e.g., ambient) pressure (in mmHg). The vapor pressure of the volatile anesthetic agent may be a known characteristic of the anesthetic agent at a given temperature (e.g., as measured by the temperature sensor 229), which is stored in a memory of the controller, such as in a lookup table. For example, an operator may input an indication of which anesthetic agent is currently contained in the vaporizer chamber 202 to the controller via an input device. Pb may be measured or estimated by an ambient pressure sensor. The calculated concentration may be used, for example, as a plausibility check for the anesthetic agent concentration measured by the concentration sensor 256.

[0053] Figure 3An embodiment of the invention may be included in an anesthesia system (e.g., Figures 1A to 1C A second exemplary embodiment of an anesthetic agent vaporizer system 300 in an anesthesia system 100 shown in FIG. Figure 1A 14. Specifically, the anesthetic agent vaporizer system 300 is an induction heated anesthetic agent vaporizer, including a vaporization chamber 302 defined by a housing 304 in which a grid 306 is disposed. The grid 306 may be formed of a structurally defined three-dimensional metal mesh, such as a FIG. 4A to FIG. 4B For example, the grid 306 may be Figure 2 The grid 206 shown may be the same or different. The heating element 308 is positioned outside the vaporization chamber 302, such as in direct contact with (e.g., touching) a lower portion of the housing 304. As another example, the heating element 308 may not be in direct contact with the housing 304. The heating element 308 may be heated by induction, such as where the heating element 308 is an induction heating coil. For example, the heating element 308 may selectively heat the grid 306 via induction without itself becoming hot and / or without directly heating additional components of the anesthetic agent vaporizer system 300 (e.g., the housing 304). However, in other examples, the heating element 308 may be heated by conduction.

[0054] The lower portion of the vaporization chamber 302 is shown as holding a liquid anesthetic 310, which is supplied from a reservoir 322 via a conduit 314 and a pump 320. The liquid anesthetic 310 can be, for example, desflurane or another liquid anesthetic having similar volatility. The pump 320 can be a positive displacement pump, such as a reciprocating positive displacement pump. The pump 320 can be selectively operated in response to a command signal from a controller 325 to deliver the liquid anesthetic 310 from the reservoir 322 to the vaporization chamber 302, as will be further described below. The controller 325 can be an electronic controller including a processor operatively connected to a memory. The controller 325 can, for example, include Figure 1A The controller 140 (eg, a portion thereof) is shown in or communicatively coupled to the controller. In addition, the pump 320 can disconnect the vaporizing chamber 302 from the sump 322 so that the sump 322 can be refilled while the anesthetic agent vaporizer system 300 is in use.

[0055] The conduit 314 may further include a shutoff valve 318 coupled between the pump 320 and the vaporization chamber 302. For example, the shutoff valve 318 may be a switch valve, wherein the shutoff valve 318 is actuated to an open (e.g., fully open) position that allows the liquid anesthetic agent 310 to flow between the reservoir 322 and the pump 320 or a closed (e.g., fully closed) position that prevents (e.g., blocks) the liquid anesthetic agent 310 from flowing between the pump 320 and the vaporization chamber 302. For example, the shutoff valve 318 may be actuated between the open position and the closed position in response to a command signal from the controller 325. A liquid return line 315 may be coupled to the conduit 314 between the shutoff valve 318 and the pump 320 to reduce pressure buildup between the shutoff valve 318 and the pump 320, such as when the shutoff valve 318 is closed. For example, excess liquid anesthetic agent 310 provided by the pump 320 may be returned to the reservoir 322 via the liquid return line 315.

[0056] The conduit 314 may also include a check valve 319 coupled between the shutoff valve 318 and the vaporizer chamber 302. The check valve 319 may be a one-way, spring-loaded check valve that allows the liquid anesthetic agent 310 to flow from the pump 320 to the vaporizer chamber 302 through the open shutoff valve 318 and prevents the liquid anesthetic agent 310 from flowing from the vaporizer chamber 302 to the pump 320. For example, the check valve 319 may automatically open (e.g., without input or adjustment from a controller or operator) to allow the liquid anesthetic agent 310 to flow to the vaporizer chamber 302, and automatically close to prevent the liquid anesthetic agent 310 from flowing back from the vaporizer chamber 310 to the pump 320. Additionally, the liquid return line 315 may include a restriction 317, such as an orifice, to control flow through the liquid return line 315 such that when the shutoff valve 318 is open, the liquid anesthetic agent 310 preferentially flows through the check valve 319 rather than the restriction 317.

[0057] The controller 325 can selectively activate the pump 320 to provide the liquid anesthetic 310 from the reservoir 322 to the vaporization chamber 302 in response to the measurement received from the liquid level sensor 324. For example, the liquid level sensor 324 can be an optical, capacitive, ultrasonic, floating, or pressure-based liquid level sensor configured to measure the level of the liquid anesthetic 310 in the vaporization chamber 302. For example, the controller 325 can be configured to maintain the level of the liquid anesthetic within a threshold range Δh. The threshold range Δh can be defined by a first lower threshold level and a second higher threshold level. The first threshold level can be a predetermined non-zero level of the liquid anesthetic calibrated to maintain a minimum distance between the grid 306 and the surface of the liquid anesthetic 310 to achieve the desired vaporization characteristics. The second threshold level can be a predetermined non-zero level of the liquid anesthetic calibrated to prevent the vaporization chamber 302 from being overfilled with the liquid anesthetic 310 and to minimize the change in the desired vaporization characteristics within the threshold range. For example, the controller 325 may activate the pump 320 in response to the level of the anesthetic agent 310 reaching a first lower threshold level, and deactivate the pump 320 in response to the level of the anesthetic agent 310 reaching a second higher threshold level. For another example, in addition or alternatively, the controller 325 may activate the pump 320 at a duty cycle selected based on the measured level of the liquid anesthetic agent and / or the measured rate of change of the level of the liquid anesthetic agent to maintain a consistent level of the liquid anesthetic agent 310 in the vaporization chamber 302. For example, the controller may input the measured level of the liquid anesthetic agent and / or the rate of change into one or more lookup tables, algorithms, or functions and output the selected duty cycle. The controller 325 may then activate the pump 320 at the selected duty cycle, which may be adjusted as the measured level of the liquid anesthetic agent and / or the rate of change of the measured level changes. For example, as the measured level increases, the duty cycle at which the pump 320 is activated may decrease, and as the measured level decreases, the duty cycle at which the pump 320 is activated may increase. In addition, a positive displacement stepper motor may also be used, where each positive displacement step of the pump is equivalent to a specified volume of anesthetic liquid. In this way, the pump can be used to accurately fill the vaporizer chamber and prevent overfilling by recording the number of pump steps delivered. The method can also be used to record the volume of anesthetic delivered to the vaporizer chamber, which may be valuable for vaporizer run time / maintenance analysis (maintenance measurement), liquid leak detection, accurate determination of the amount of liquid anesthetic remaining and available for delivery, vaporization efficiency calculation, etc. In addition, in some examples, a liquid level switch 313 may be included to prevent the vaporizer chamber 302 from being overfilled with liquid anesthetic 310.

[0058] The upper portion of the vaporization chamber 302 (e.g., above the surface of the liquid anesthetic 310) holds the vaporized anesthetic. For example, the liquid anesthetic 310 may have a relatively low boiling point, such as at or around room temperature, so that the liquid anesthetic 310 can be vaporized without adding additional heat. However, due to the latent heat of vaporization, vaporization can reduce the temperature of the liquid anesthetic 310, and changes in the temperature of the liquid anesthetic 310 can result in changes in the amount of vaporized anesthetic produced. By activating the heating element 308 to heat the grid 306, the latent heat of vaporization can be provided for the phase change from the liquid form of the anesthetic to the vapor and keep the temperature of the liquid anesthetic 310 constant, thereby maintaining a substantially constant vaporization rate. As a non-limiting example, the temperature of the liquid anesthetic can be maintained at 35°C, as described below. In addition, the inductively heated grid 306 can provide a surface for nucleating boiling of the liquid anesthetic 310 to produce vapor bubbles 312.

[0059] A fresh gas flow containing one or more medical grade gases such as oxygen, air, nitrous oxide, and combinations thereof may enter the anesthetic agent vaporizer system 300 via the first gas passage 336. The fresh gas flow may be delivered via one or more gas conduits (e.g., via Figure 1C The pipe connection 46 shown) and / or one or more gas holding cylinders (e.g., via Figure 1C The cylinder bracket 44 of the first gas channel 336 is provided. The first proportional valve 343 connected to the first gas channel 336 can be adjusted by the controller 325 to control the amount (or flow rate) of fresh gas flowing through the first gas channel 336. The first proportional valve 343 can be a variable valve, such as a continuously variable valve, which can be adjusted by the controller 325 between multiple positions within the range of a fully open position and a fully closed position. For example, as the opening degree of the first proportional valve 343 increases, the amount (e.g., flow rate) of fresh gas flowing through the first gas channel 336 can increase. The first mass flow sensor 341 can be connected to the first gas channel 336 downstream of the first proportional valve 343 to measure the flow rate of the fresh gas flow entering the anesthetic gasifier system 300. For example, the first mass flow sensor 341 can be an ultrasonic flowmeter. The entire fresh gas flow provided to the anesthetic gasifier system 300 can bypass the gasification chamber 302.

[0060] The anesthetic agent vapor may exit the vaporizer chamber 302 via a second gas passage 340 (e.g., a vapor delivery passage). For example, the second gas passage 340 may pass through an opening at or near the top of the housing 304 and form a junction 342 with the first gas passage 336 to fluidly couple the upper portion of the vaporizer chamber 302 with the first gas passage 336. The second gas passage 340 is shown as including a check valve 348. The check valve 348 may be a one-way valve that allows vaporized anesthetic agent to flow from the vaporizer chamber to the junction 342 and prevents vaporized anesthetic agent and / or fresh gas from flowing from the junction 342 to the vaporizer chamber 302. For example, the check valve 348 may automatically open (e.g., without input or adjustment from a controller or operator) to allow the vaporized anesthetic agent to flow to the junction 342, and automatically close to prevent gas from flowing to the vaporizer chamber 302.

[0061] The second gas passage 340 also includes a shutoff valve 350 and a second proportional valve 352 located in a manifold heater 354 downstream of the check valve 348. The shutoff valve 350 can be an electronic or mechanically actuated valve that is adjusted in response to input from the controller 325 and / or an operator. For example, the shutoff valve 350 can be an on-off valve, wherein the shutoff valve 350 is actuated to an open (e.g., fully open) position that allows gas to flow through the shutoff valve 350 or a closed (e.g., fully closed) position that prevents (e.g., blocks) gas from flowing through the shutoff valve 350 in response to an appropriate command signal from the controller 325. For example, the shutoff valve 350 can be closed to quickly stop the supply of anesthetic to the patient. The second proportional valve 352 can be a variable valve, such as a continuously variable valve, which can be adjusted by the controller 325 between a plurality of positions within a range of a fully open position and a fully closed position. For example, as the opening degree of the second proportional valve 352 increases, the amount (e.g., flow rate) of vapor flowing from the vaporizing chamber 302 to the first gas passage 336 (e.g., via the second gas passage 340) may increase. Conversely, as the opening degree of the second proportional valve 352 decreases, the amount of vapor delivered from the vaporizing chamber 302 to the first gas passage 336 may decrease. The manifold heater 354 may heat the shutoff valve 350 and the second proportional valve 352 to prevent condensation of the vaporized anesthetic agent in the valves. As a non-limiting example, the manifold heater 354 may be operated to maintain the shutoff valve 350 and the second proportional valve 352 at a substantially constant temperature, such as 40°C.

[0062] The fresh gas flow not containing the vaporized anesthetic agent and the vaporized anesthetic agent from the vaporizer 302 are mixed at and downstream of the junction 342. The mixed gas can then be passed through the inspiratory branch of the breathing circuit (e.g., via a relative Figure 1BThe second mass flow sensor 344 may be coupled to the first gas channel 336 downstream of the junction 342 with the second gas channel 340 to measure the flow rate of the mixed gas leaving the anesthetic gasifier system 300. For example, the second mass flow sensor 344 may be an ultrasonic flow meter or a calorimetric (thermal) mass flow meter. With respect to the ultrasonic flow metering architecture, the output anesthetic concentration may be calculated by the difference in TOF between the measured upstream ultrasonic flow sensor 341 and the downstream ultrasonic flow sensor 344. In addition, an independent concentration sensor 356 may be coupled to the first gas channel 336 downstream of the junction 342 with the second gas channel 340. The concentration sensor 356 may be any suitable sensor configured to measure the concentration of the anesthetic agent in the mixed gas. In one example, the concentration sensor 356 may be an optical sensor that transmits light of a suitable wavelength (e.g., infrared) through the mixed gas and determines the concentration of the anesthetic agent based on the absorption of the light by the mixed gas. In other examples, the concentration sensor can be a carbon dioxide or oxygen sensor that measures the concentration of the anesthetic agent based on the displacement of carbon dioxide or oxygen relative to the supply concentration of carbon dioxide or oxygen in the fresh gas flow. The concentration sensor 356 can output a signal indicating the measured anesthetic agent concentration (e.g., the concentration of anesthetic agent vapor) in the mixed gas to the controller 325.

[0063] In addition to receiving the signals output by the liquid level sensor 324, the concentration sensor 356, the first mass flow sensor 341, and the second mass flow sensor 324, the controller 325 may also receive additional signals, including: the measured level of the liquid anesthetic 310 in the storage tank 322 from the liquid level sensor 321, which may be, for example, an infrared liquid level sensor; the measured vapor pressure (P) inside the vaporization chamber 302 from the pressure sensor 330 coupled to the upper portion of the vaporization chamber 302; 气体 ); the measured fresh gas flow pressure (P1) from the pressure sensor connected to the second gas passage 338 upstream of the joint 342; the measured vapor temperature (T 气体 ); the measured temperature of the grid 306 from the temperature sensor 328 coupled to the grid 306 (T 栅格 ); and the temperature (T of the liquid anesthetic 310 measured by the temperature sensor 329 immersed in the liquid anesthetic 液体 ). The controller 325 receives the Figure 3 various sensor signals, process the input data, and use Figure 3The various actuators of the controller 325 adjust the operation of the anesthetic agent vaporizer system 300 based on the received signals and the instructions stored on the memory of the controller. For example, the controller 325 may receive the measured anesthetic agent concentration from the concentration sensor 356 and adjust the position of one or more of the first proportional valve 343 and the second proportional valve 352, as described below with respect to Figure 7 As further described. For example, the controller 325 may receive T from the temperature sensor 328. 栅格 , T from the temperature sensor 329 液体 and the current or voltage supplied to the heating element 308 based on the input measurement results, as described below with respect to Figure 8 Further described.

[0064] Additionally, data may be input to the controller 325 by an operator of the anesthetic agent vaporizer system 300 via a user input device 326 that is operatively connected to the controller and thus configured to transmit input signals to the controller 325 (e.g., via wired or wireless communication). The user input device 326 may include one or more of a mouse, a keyboard, a voice input device, a touch input device for receiving gestures from an operator, a motion input device for detecting non-touch gestures and other actions of an operator, and other similar input devices, as well as associated processing elements capable of receiving user input from an operator.

[0065] Additionally, the controller 325 may calculate the concentration of the anesthetic agent output by the anesthetic agent vaporizer system 300 and delivered to the patient according to the following formula:

[0066]

[0067] Wherein agent % is the percentage concentration of anesthetic agent in the inspiratory branch of the breathing circuit, Fv is the measured flow rate of gas through the vaporizer (in mL / min, such as measured by the second mass flow sensor 344), Ft is the total fresh gas flow entering the vaporizer (in L / min, such as measured by the first mass flow sensor 341), VPa is the vapor pressure of the volatile anesthetic agent (in mmHg), and Pb is the barometric (e.g., ambient) pressure (in mmHg). The vapor pressure of the volatile anesthetic agent may be a known characteristic of the anesthetic agent at a given temperature (e.g., as measured by the temperature sensor 329), which is stored in a memory of the controller, such as in a lookup table. For example, an operator may input the anesthetic agent used into the controller via an input device. Pb may be measured or estimated by an ambient pressure sensor. The calculated concentration may be used, for example, as a plausibility check for the anesthetic agent concentration measured by the concentration sensor 356.

[0068] Next, FIG. 4A to FIG. 4BA first cross-sectional view 400 and a second cross-sectional view 450 are respectively shown of a vaporizer chamber 402 that may be included in an anesthetic agent vaporizer system. The vaporizer chamber 402 is Figure 2 The gasification chamber 202 and / or Figure 3 A non-limiting example of a gasification chamber 302 is shown. Reference axis 499 is provided for describing the relative arrangement of components. Figure 4A The first view 400 is a side view in the xz plane and is a two-dimensional (2D) representation of a three-dimensional (3D) object. The second view 450 is a perspective view, as indicated by reference axis 499.

[0069] A grid 406 is shown disposed within the gasification chamber 402, such as within the interior of the housing 404 of the gasification chamber 402. The grid 406 may be, for example, Figure 2 Grid 206 or Figure 3 The grid 306. The grid 406 may be provided by a heating element 408, which is shown as an induction heating coil (which may be, for example, Figure 2 The heating element 206 shown or Figure 3 The grid 406 is inductively heated by the heating element 306 shown in the figure. The positioning of the grid 406 in the housing 404 and therefore relative to the positioning of the heating element 408 can be optimized to provide the desired heating effect for a given heater power. For example, the magnetic field generated by the heating element 408 decreases in proportion to the square of the radial distance from the heating element. Therefore, even at the relatively high heater power of the heating element 408, the relatively large radial distance between the grid 406 and the heating element 408 can also cause the relatively low and / or slow temperature rise of the grid 406. Therefore, the size and / or shape of the grid 406 can be set to position at least the outer circumference of the grid 406 within the threshold distance of the housing 404 and therefore the heating element 408, wherein the threshold distance is relatively small. In one example, the threshold distance between the grid 406 and the housing 404 is in the range of 1mm to 10mm. In another example, the threshold distance is less than 1mm. In this manner, the grid 406 or other suitable magnetically conductive target (e.g., a stainless steel tube) can be positioned in close proximity to the heating element 408 via the wall of the housing 404 to achieve efficient energy transfer. For example, as the distance (e.g., radial distance) between the grid 406 and the heating element 408 decreases, the energy transfer efficiency increases. Figure 4A and Figure 4B As shown, heating element 408 is positioned outside housing 404 at a vertical position (in the z-direction) that overlaps the vertical position of grid 406 within housing 404. In this manner, heating element 408 substantially surrounds grid 406 (with housing 404 positioned intermediate heating element 408 and grid 406).

[0070] The grid 406 may be comprised of a mesh of wires (or rods) and a base 410. The base 410 may be specifically formed to engage with the housing 404 of the gasifier chamber of the gasifier. In addition, the entire grid 406 may be comprised of a single unitary material such as metal. The grid 406 may be comprised of a high magnetic permeability material such as stainless steel. The grid 406 includes a plurality of vertical wires 412 having a length extending in the z-direction (relative to the reference axis 499), a plurality of horizontal wires 414 having a length extending in the x-direction (relative to the reference axis 499), and a plurality of circular wires 416 to form a mesh. The vertical wires 412 are perpendicular to the horizontal wires 414. Note that in Figure 4A In the cross-sectional view shown, the circular line 416 is represented by a cross-sectional circle rather than showing each circular line.

[0071] As particularly shown in the second view 450, the grid 406 can be cylindrical in shape and have a hollow cylindrical cavity 418 in the center. The circular lines 416 are arranged as evenly spaced concentric circles in a series of coplanar sets (e.g., in the xy plane relative to the reference axis 499), starting from the cylindrical cavity 418 (e.g., the innermost circular line) and ending at the perimeter of the grid 406 (e.g., the outermost circular line). The coplanar sets are aligned in the x-direction and the y-direction and distributed vertically (e.g., in the z-direction). For example, the coplanar sets can be equally spaced in the z-direction from the bottommost coplanar set to the topmost coplanar set.

[0072] Horizontal lines 414 extend radially from cylindrical cavity 418 to the perimeter of grid 406 in a series of coplanar sets (e.g., in an xy plane relative to reference axis 499). Similar to the coplanar sets of circular lines 416, the coplanar sets of horizontal lines 414 are aligned in the x-direction and the y-direction and are distributed vertically (e.g., in the z-direction). In addition, each coplanar set of horizontal lines 414 overlaps with one of the coplanar sets of circular lines 416, such that horizontal lines 414 and circular lines 416 intersect. For example, horizontal lines 414 and circular lines 416 may merge at each intersection point.

[0073] Vertical lines 412 are distributed radially from cylindrical cavity 418 to the perimeter of grid 406 in a series of equally spaced concentric sets. Each concentric set has the same diameter as one of circular lines 416, so that vertical lines 412 also intersect horizontal lines 414 and circular lines 416 at each intersection point. For example, vertical lines 412 may also merge into horizontal lines 414 and circular lines 416 at each intersection point.

[0074] In some embodiments, the grid 406 may also include a filter having a fine porosity. For example, the filter may be positioned at or near the bottom of the base 410 and / or within the cylindrical cavity 418. In at least some examples, when included, the base 410 and the filter may form a continuous piece. The filter may be configured to receive a flow of carrier gas and may generate bubbles within the liquid anesthetic, as described above with respect to Figure 2 The pore size of the filter element can be selected to optimize the size of the bubbles, such as to maximize the surface area of ​​the carrier gas in contact with the liquid anesthetic agent and to produce a defined and uniform gas distribution. The pore size of the filter element can be further optimized to reduce the pressure drop across the filter element. In addition, the pore size and distribution can be optimized to produce a desired swirl pattern of the generated bubbles.

[0075] The network of grids 406 provides a high surface area to thermal mass ratio relative to structures constructed from a solid block of metal or constructed entirely from a highly porous metal filter. The high surface area to thermal mass ratio enables efficient heating by the heating element 408 and a fast thermal response time. For example, the high surface area to thermal mass ratio enables the grids 406 to heat quickly to a desired operating temperature when the heating element 408 is powered on, and enables the grids 406 to cool quickly (e.g., to room temperature) when the heating element 408 is turned off. In addition, the high surface area to thermal mass ratio enables the temperature gradient to be changed quickly during operation of the anesthetic agent vaporizer system (e.g., by adjusting the heater power of the heating element 408).

[0076] Note that in other embodiments, the shape of the grid 406 may be different from Figure 4A and Figure 4B For example, the geometry of the grid 406 can be adjusted via additive manufacturing.

[0077] Grid 406 can be manufactured using a suitable manufacturing process such as welding. For example, a first group of concentric circular lines can be welded to a first group of coplanar horizontal lines to form a first circular grid. Then, a group of vertical lines can be welded to the first circular grid, such as welding a vertical line to each intersection of the first circular grid to form a first circular grid structure. A plurality of such circular grid structures can be formed, such as six circular grid structures. Then, each circular grid structure can be welded together to form a stacked grid structure. For example, the first circular grid structure can be welded to the second circular grid structure by welding each unattached end of each vertical line of the first circular grid structure to the corresponding intersection of the second circular grid of the second circular grid structure (on the side opposite to the vertical line of the second circular grid structure). Once all circular grid structures are welded together, the final circular grid can be welded to the remaining unattached end of the vertical line, and the entire grid can be welded to the filter in the base and / or the central cavity. Other manufacturing processes are also possible, such as casting, injection molding, etc.

[0078] However, the above-described methods of manufacturing grid 406 may be time consuming and expensive. Additionally, some manufacturing methods may be limited by how small the wire diameter and / or spacing of the grid can be, resulting in less desirable grid characteristics that may reduce or slow vaporization of the liquid anesthetic agent. Additionally, if a different grid geometry is desired, the above-described methods may require the manufacture of new molds or other equipment, which may limit the changes that can be made to the grid geometry.

[0079] Thus, as described in detail below, grid 406 may be manufactured using an additive manufacturing process such as 3D printing. By utilizing additive manufacturing, complex stacked and intersecting grid structures may be manufactured in a rapid and low-cost manner without the need for multiple separate structures to be welded or otherwise fastened together, which may compromise structural integrity. Additionally, changes to the geometry of the grid, such as changes in wire thickness and / or spacing, and changes to the overall size of the grid may be made by adjusting the grid model used as an illustration of additive manufacturing, and without the need for completely different manufacturing equipment. Thus, a variety of different grids may be manufactured at scale and at low cost for different sized vaporization chambers and / or for different desired properties.

[0080] Fig. 9 is a flow chart illustrating an exemplary method 900 for manufacturing a grid configured to be received in a vaporizer chamber of an anesthetic agent vaporizer system, such as Figure 4A and Figure 4B 406. The method 900 may be performed at least in part by a 3D printing device that is operatively / communicatively coupled to a printer interface computing device.

[0081] At 902, method 900 includes obtaining or generating a 3D model of a grid. The model of the grid may be a computer-aided design (CAD) file, an additive manufacturing file (AMF), or other 3D modeling file. The 3D model of the grid may be generated on a printer interface computing device. In some examples, the 3D model may be generated entirely from operator instructions via a CAD or other program. In other embodiments, the 3D model may be generated at least in part based on information received from a 3D scanner (e.g., a laser scanner) that may image a physical model of the grid. The 3D model may define the dimensions of the grid, the external and internal structure of the grid, and the material properties of the grid, thereby fully representing in a digital format the final form of the grid to be produced. Figure 4A and Figure 4B As shown, the grid includes voids (e.g., empty spaces), and thus the 3D model of the grid may include support structures, filler materials, or other features that allow printing over the voids. The 3D model may include a base portion and / or an internal filter of the grid, so as to produce a grid including a base portion and / or an internal filter integrated with the grid's network. In other embodiments, the base portion and / or the internal filter may be manufactured separately from the grid's network and therefore may not be included in the 3D model.

[0082] At 904, a plurality of 2D slices of the 3D model of the grid are generated. The slices may be generated on the printer interface computing device and then sent to the printing device as an STL file, or the 3D model of the grid may be sent to the printing device and the printing device may slice the 3D model into a plurality of slices to generate an STL file. In doing so, the 3D model is sliced ​​into hundreds or thousands of horizontal layers having a suitable thickness, such as a thickness in the range of 0.1 mm to 3 mm.

[0083] At 906, the printing device prints the first slice on a build plate or other suitable base material. When the printing device prints from an STL file, the printing device creates or prints a grid layer by layer on the build plate. The printing device reads each slice (or 2D image) from the 3D model and continues to create the 3D grid by laying down (or printing) successive layers of material on the upper plane of the build plate until the entire grid is created. Each of these layers can be viewed as a thin slice horizontal section of the final completed or printed 3D grid.

[0084] The printing device may be a suitable device configured to print metal and / or other high magnetic permeability materials such as aluminum or stainless steel. The printing device may utilize selective laser melting (SLM) technology, direct metal laser sintering (DMLS) technology, or other suitable metal printing technology. In examples where the void is initially filled with a soluble filler material, the printing device may be configured to print multiple materials (e.g., metal and filler material) and may therefore include more than one printing head.

[0085] During printing, one or more print heads are moved in horizontal and vertical directions by a controlled mechanism operated by control software running on the printing device, such as a computer-aided manufacturing (CAM) software package suitable for use with the printing device, to complete or print each layer of the 3D model. The build plate is typically stationary with its upper plane parallel to the horizontal plane, although in some examples the build plate may be moved vertically up and down (i.e., in the z-direction). The printed material solidifies to form a layer (and seals the layers of the 3D grid together), and then the print head or build plate is moved vertically before starting to print the next layer. The process is repeated until all layers of the 3D grid have been printed.

[0086] Thus, at 908, each additional slice is sequential. At 910, the printed grid is dried and / or cured. Drying / curing of the printed grid may be performed after each layer is deposited, and / or drying / curing may be performed after the entire grid is printed. At 912, all void material is removed. For example, if a filler material is printed in the voids, the grid may be placed in water, acid, or other solvent to dissolve the filler material. For another example, if a support structure is printed in the voids (e.g., a stent-like structure or a perforated structure), the support structure may be removed manually and / or with a tool.

[0087] Thus, method 900 provides 3D printing of a grid suitable for being housed in a vaporization chamber of an anesthetic delivery system. Although method 900 involves printing the entire grid as a single component, in some examples, the 3D model of the grid may include multiple 3D models, each model representing a different section of the grid. For example, the grid may be divided into multiple parts, such as a first section, the first section including a base portion, a first set of concentric circular lines, a first set of coplanar horizontal lines (as described above, which may collectively form a first circular grid) and a first set of vertical lines extending from the first circular grid (thereby collectively forming a first circular grid structure); a second section, the second section including a second circular grid section; a third section, the third section including a third circular grid structure; and so on. Each section can be printed independently, and then the sections can be stacked and fused together using a suitable mechanism. In such examples, the void structure can be reduced or eliminated, which can reduce manufacturing costs.

[0088] In another example, a mold can be used to make the grid. The mold can be created by first 3D printing the grid model in a suitable material that can be solid at room temperature but becomes liquid at a relatively low temperature above room temperature, such as wax. A plaster mold can be formed over the wax model, and after the plaster dries, the wax can be melted and drained from the mold. The mold can then be filled with molten metal. Once the metal cools, the plaster can be removed to create the grid.

[0089] Therefore, the above is relative to Figure 4A and Figure 4B The grid can be manufactured using additive manufacturing techniques such as 3D printing. In one example, the grid described herein can be manufactured according to a computer-readable medium containing computer-readable instructions, which, when executed on a 3D printer, causes the printer to print a grid, wherein the grid includes a plurality of stacked sets of concentric circular lines, each set of concentric circular lines being connected to a corresponding set of horizontal lines, each horizontal line extending outward from the centermost circular line to the outermost circular line. The grid also includes a set of vertical lines connected to the concentric circular line set, each vertical line extending from the topmost concentric circular line set to the bottommost concentric circular line set. In some examples, the grid includes a porous filter contained in the most central circular line of each concentric circular line set. In some examples, the grid also includes a base portion connected to the bottommost concentric circular line set and / or the porous filter. In some examples, the grid includes a base shaped to engage with a component of the vaporization chamber. The grid can be a vaporizer grid for assisting liquid vaporization.

[0090] In one example, a method for creating a computer-readable 3D model suitable for additive manufacturing of a grid is provided, the grid being configured to be contained in a vaporization chamber of an anesthetic delivery system, wherein the grid includes a plurality of stacked sets of concentric circular lines, each set of concentric circular lines being coupled to a corresponding set of horizontal lines, each horizontal line extending outwardly from a centermost circular line to an outermost circular line. The grid also includes a set of vertical lines coupled to the set of concentric circular lines, each vertical line extending from a topmost set of concentric circular lines to a bottommost set of concentric circular lines. In one example, the method includes obtaining specifications of the grid. The specifications may be obtained from user input (e.g., via a 3D modeling program such as CAD) and / or information obtained from a 3D scanner. For example, a 3D scanner may image a physical model or prototype of the grid. The method also includes generating a computer-readable 3D model of the grid based on the obtained specifications. The 3D model may be generated using CAD or other 3D modeling programs. In some examples, the method also includes sending the 3D model to a printing device. The 3D model may be converted into an STL file or other suitable format that can be read by a printing device. The printing device can then print the grid according to the specifications shown in the 3D model. The grid can be, for example Figure 4A and Figure 4B Grid 406.

[0091] An anesthetic agent vaporizer system (such as Figures 2 to 4B The system shown in FIG. 1 can be controlled in various ways to deliver a desired concentration of vaporized anesthetic to a patient. In one example, Figure 5 and Figure 6 As shown, the controller (e.g., Figure 2Controller 225 or Figure 3 The controller 325) can control agent delivery separately from heater control. For example, the controller can be a proportional-integral-derivative (PID) controller with separate control loops for agent delivery and heater control. Therefore, in some embodiments, the heater may not be adjusted to change the amount of vaporized anesthetic agent produced.

[0092] First go to Figure 5 , a block diagram of an exemplary reagent delivery control circuit 500 that can be implemented by a controller is shown. In addition, the control of reagent delivery will be described below with respect to Figure 7 The control circuit 500 outputs a first proportional valve (eg, Figure 2 The first proportional valve 243 or Figure 3 The control circuit 500 also outputs a command position of a first proportional valve 343, referred to herein as PV1, which controls the flow of the vaporized anesthetic agent from the vaporizer to the junction where the vaporized anesthetic agent is mixed with fresh gas before being delivered to the patient. Figure 2 The second proportional valve 252 or Figure 3 The command position of the second proportional valve 352 of the anesthetic agent is determined, referred to herein as PV2. Each of the command valve positions (PV1 and PV2) is determined based on the difference between the commanded anesthetic agent concentration and the measured anesthetic agent concentration. In addition, the command valve position may take into account the temperature of the grid that vaporizes the anesthetic agent (which may affect the final anesthetic agent concentration), as well as the pressure upstream and downstream of the junction where the vaporized anesthetic agent mixes with the fresh gas flow, and the fresh gas velocity upstream of the junction.

[0093] The controller receives a commanded concentration of vaporized anesthetic agent for delivery (e.g., an agent concentration setpoint received via user input) as a commanded agent % 502. The commanded agent % 502 is input into the interface 504 along with an agent % feedback signal 524. The agent % feedback signal 524 is derived from a measured agent % 522 (e.g., Figure 2 The concentration sensor 256 or Figure 3 The difference between the commanded reagent % 502 and the reagent % feedback signal is determined to generate a resulting error value 506 which is input into a proportional valve plant model 508 .

[0094] Induction heating grid (T 栅格 )510 temperature (for example, Figure 2 The temperature sensor 228 or Figure 3The current proportional valve setting 512 is also input into the proportional valve plant model 508. The current proportional valve setting 512 corresponds to the position (or setting) of the first proportional valve P1 and the second proportional valve P2.

[0095] Proportional valve equipment model 508 using error 506, T 栅格 510 and the current proportional valve setting 512 to update the proportional valve setting. For example, the controller may continuously calculate the error value 506 as the difference between the command reagent % 502 and the reagent % feedback signal 524, and apply a correction to the proportional valve setting based on the proportional term, the integral term, and the differential term. However, the updated (e.g., corrected) proportional valve setting may first pass through the noise compensation block 514 along with the noise variables. The noise variables include a first pressure (P1) 516 (e.g., Figure 2 Pressure sensor 231 or Figure 3 331), a second pressure (P2) 518 (e.g., downstream of the junction where the vaporized anesthetic agent mixes with the fresh gas flow), and a velocity (V1) 520 (e.g., as measured by the pressure sensor 331 of FIG. 5 ). Figure 2 Mass flow sensor 241 or Figure 3 The noise compensation block 514 can take into account disturbances in the system (in addition to the proportional valve position) that can affect the reagent concentration, including, for example, the pressures of the fresh gas and fresh gas / vaporized anesthetic mixture (P1 and P2) and the velocity of the fresh gas flow. The control loop can then output an updated proportional valve setting 526 (e.g., PV1 and PV2). The reagent concentration 522 measured by the reagent concentration sensor is directly affected by the position of the proportional valve, so the measured reagent concentration is used as the feedback process variable.

[0096] Continue to Figure 6 , a block diagram of an exemplary heater control loop 600 that may be implemented by a controller is shown. Additional heater controls will be described below with respect to Figure 8 Described. The control loop 600 outputs a command heater power for the inductive heating element so that the grid is heated to a desired temperature for vaporizing the anesthetic agent. The command heater power is determined based on the difference between the desired temperature of the grid and the measured temperature of the grid. In addition, the command heater power can take into account the temperature of the vaporized anesthetic agent and the command concentration of the vaporized anesthetic agent to be delivered via the anesthetic vaporizer system, which can affect the heater power output. The heater power can also be monitored to serve as an inference of the amount of energy transferred to the grid (e.g., the heated target) via a lookup table, which can be used to prevent the target from overheating. The heater coil inductance can also be measured to monitor the health and status of the heater target system.

[0097] The controller receives the command temperature (T wall-cmd) 602 (eg, a temperature setting value received via user input and / or selected based on user input). wall-cmd 602 and T 栅格 The feedback signal 624 is input into the joint 604. 栅格 Feedback signal 624 is derived from the measurement of T 栅格 622 (for example, Figure 2 The temperature sensor 228 or Figure 3 The temperature sensor 328 measures the temperature of the wall-cmd 602 and T 栅格 The difference between the feedback signals 624 is used to generate a resultant error value 606 which is input into a plant model 608 which also receives the currently measured T 栅格 As input 610. For example, in addition to measuring T 栅格 In addition to 622, it can also include T 栅格 Input 610 for redundancy and error capture (e.g., T values ​​that are not within a threshold of each other, such as 2°C). 栅格 Input 610 and measure T 栅格 622 temperature may indicate a temperature sensor error). The device model 608 uses the error 606 and T 栅格 Input 610 is used to update the heater power command to the inductive heating element. For example, the controller may continuously calculate the error value 606 as T wall-cmd 602 and T 栅格 The difference between the feedback signals 624 is calculated and a correction is applied to the commanded heater power output based on the proportional, integral, and derivative terms.

[0098] However, the updated heater power command may first be passed through the noise compensation block 614 along with noise variables. The noise variables include the measured vapor temperature (T 气体 )618(For example, Figure 2 The temperature sensor 232 or Figure 3 The noise compensation block 614 can take into account the system that may affect T 栅格 interference (other than the heater output of the heating element), including for example T 气体 and measuring reagent % (e.g., Figure 2 The concentration sensor 256 or Figure 3 The control loop may then output an updated heater power command 626. The measured T measured by the temperature sensor coupled to the heating grid 栅格 622 is directly affected by the heater power output by the heating element and therefore uses the grid measured temperature as the feedback process variable.

[0099] Next, Figure 7 A method 700 is shown for operating an anesthetic vaporizer system to deliver a desired concentration of vaporized anesthetic to a patient, the anesthetic vaporizer system including an inductively heated grid, such as a heating element, immersed in liquid anesthetic in a vaporization chamber. Figures 2 to 4B The method 700 may be performed by a controller such as Figure 2 Controller 225 or Figure 3 The controller 325 responds to the commands stored in the memory of the controller and in conjunction with one or more sensors (e.g., Figure 2 Concentration sensor 256 or Figure 3 concentration sensor 356) and an actuator (e.g., Figure 2 The heating element 208 or Figure 3 The heating element 308, Figure 2 The first proportional valve 243 or Figure 3 The first proportional valve 343, Figure 2 The second proportional valve 252 or Figure 3 The method 700 may be performed by controlling the second proportional valve 352 of the embodiment of the present invention. For example, electrical power may be supplied to the heating element to heat the metal grid to a desired temperature to facilitate vaporization of the liquid anesthetic agent, and one or more valves may be adjusted to control the concentration of the vaporized anesthetic agent delivered to the patient. For example, the method 700 may be performed in response to a request to deliver an anesthetic agent to the patient (e.g., based on user input).

[0100] At 702, an anesthetic concentration setpoint is received. The anesthetic may be any suitable volatile liquid anesthetic, such as desflurane, isoflurane, sevoflurane, etc., or another drug that may be aerosolized / inhaled, such as albuterol. The concentration setpoint may be a percentage of the vaporized anesthetic per volume of the fresh gas / vaporized anesthetic mixture provided to the patient. The concentration setpoint may be input by a user of the controller (e.g., via Figure 2 Input device 226 or Figure 3 The concentration setting value is obtained by an input device 326 of the anesthetic agent or by another suitable mechanism, and refers to the desired concentration of the anesthetic agent to be delivered to the patient.

[0101] At 704, method 700 includes supplying power to the heating element. Figure 2 As described above, the heating element may be an induction heating element configured to selectively raise the temperature of the grid to a desired temperature. In some examples, the desired temperature may be a predetermined set temperature for the type of anesthetic being used. Figure 5 and Figure 6 As described above, the amount of power supplied to the heating element can be controlled independently of the amount of anesthetic delivered to the patient. An exemplary heater control routine will be described below with respect to Figure 8By supplying power to the heating element, liquid anesthetic agent within a vaporization chamber of an anesthetic agent vaporizer system can be effectively vaporized.

[0102] At 706, method 700 includes opening one or more valves based on the anesthetic concentration set value. For example, the anesthetic gasifier system may include one or more proportional valves and one or more shut-off valves for controlling the flow of gas through the anesthetic gasifier. For example, a first proportional valve that controls the amount (or flow rate) of fresh gas entering the anesthetic gasifier system may be adjusted to a default open position. As another example, a controller may adjust the open position of the first proportional valve based on the anesthetic concentration set value. For example, the controller may input the anesthetic concentration set value into one or more lookup tables, functions, or algorithms, which may then output the position (or setting) of the first proportional valve. The controller may then transmit a command signal to the first proportional valve to adjust the first proportional valve to the output position. For example, as the anesthetic concentration set value increases, the degree of opening of the first proportional valve may increase to achieve a higher flow rate of fresh gas through the anesthetic gasifier system.

[0103] Similarly, the opening position of the second proportional valve that controls the amount (or flow rate) of vaporized anesthetic agent flowing out of the vaporizer chamber can be determined based on the anesthetic agent concentration set point. For example, the controller can input the anesthetic agent concentration set point into one or more lookup tables, functions, or algorithms, which can then output the position (or setting) of the second proportional valve. In some embodiments, the controller can also take into account the setting of the first proportional valve and / or the measured fresh gas flow rate entering the vaporizer system (e.g., Figure 2 The first mass flow sensor 241 or Figure 3 The controller may then transmit a command signal to the second proportional valve to adjust the second proportional valve to an output position. For example, as the anesthetic concentration set point increases, the opening degree of the second proportional valve may increase to allow a larger amount of vaporized anesthetic to flow out of the vaporization chamber. In addition, a shutoff valve such as Figure 2 Shut-off valves 246 and 250 or Figure 3 The shut-off valve 350 may be actuated to its fully open position.

[0104] At 708, method 700 includes determining the concentration of the anesthetic agent. For example, the concentration of the anesthetic agent supplied to the patient may be measured by a concentration sensor, which may be positioned in a gas outlet passage (e.g., Figure 2 The first gas channel 236 or Figure 3 The concentration sensor may output a signal corresponding to the measured concentration of the anesthetic agent to the controller.

[0105] At 710, method 700 includes determining an anesthetic concentration error. The anesthetic concentration error may be the difference between a set agent concentration and a measured agent concentration. For example, the anesthetic concentration error (ERR) may be calculated as:

[0106] ERR = Reagent 实际 -Reagents 设定值

[0107] Reagents 实际 is the concentration of the anesthetic agent supplied to the patient (e.g., as determined at 708), and the agent 设定值 A value is set for the anesthetic agent concentration (eg, as received at 702).

[0108] At 712, method 700 includes determining whether the anesthetic concentration error is within an acceptable range. For example, the acceptable range may be defined by a lower threshold and an upper threshold. In some examples, the lower threshold may be an anesthetic concentration error value corresponding to an anesthetic concentration value that is a certain percentage below the anesthetic concentration setting value, and the upper threshold may be an anesthetic concentration error value corresponding to an anesthetic concentration value that is the percentage above the anesthetic concentration setting value. Thus, the acceptable range may encompass anesthetic concentration error values ​​corresponding to anesthetic concentrations supplied to the patient that are maintained within the percentage of the anesthetic concentration setting value. In some examples, the percentage may vary based on one or more of the anesthetic concentration setting value and the anesthetic used, such that the percentage may be smaller when the anesthetic used is more accurately controlled.

[0109] If the anesthetic concentration error is within the allowable range, method 700 returns to 708 and includes continuing to determine the anesthetic concentration. In this way, the anesthetic concentration error can be updated when the anesthetic concentration supplied to the patient changes. If the anesthetic concentration error is not within the allowable range, method 700 advances to 714 and includes adjusting the opening of one or more valves based on the error. For example, if the error indicates that the measured anesthetic concentration is less than the concentration set point (and exceeds the allowable range), the opening of the first proportional valve and / or the second proportional valve can be increased to increase the amount of vaporized anesthetic flowing out of the vaporizer chamber and delivered to the patient. Conversely, if the error indicates that the measured anesthetic concentration is greater than the concentration set point (and exceeds the allowable range), the opening of the first proportional valve and / or the second proportional valve can be reduced to reduce the amount of vaporized anesthetic flowing out of the vaporizer chamber and delivered to the patient. In one example, a proportional-integral-derivative controller can be used to adjust the proportional valve setting to drive the measured agent concentration toward the concentration set point, as described above with respect to Figure 5Additionally, in some embodiments, the opening of the one or more valves may be further adjusted based on noise variables in the system such as fresh gas flow rate and pressure and / or temperature of the inductively heated grid. In some embodiments, the anesthetic agent vaporizer system may include a pressure regulator (e.g., Figure 2 The pressure regulator 242 of the anesthetic gasifier system controls the gas pressure in the vaporizer chamber, thereby fixing the gas pressure boundary condition of the second proportional valve. In such an example, the second proportional valve can be adjusted based on the anesthetic concentration error without adjusting the first proportional valve. In other embodiments, such as when the anesthetic gasifier system does not include a pressure regulator (such as Figure 3 The anesthetic agent vaporizer system 300 shown in FIG. 1 may simultaneously adjust the first proportional valve and the second proportional valve via a feedback control loop to achieve the same net effect of using a pressure regulator and a second proportional valve. The method 700 then returns to continue measuring the anesthetic agent concentration and adjusting the opening of the one or more valves based on the error between the set value and the measured agent concentration until the system is deactivated and anesthetic agent is no longer supplied to the patient.

[0110] Now go to Figure 8 , showing a method for operating an anesthetic agent vaporizer system such as Figures 2 to 4B Method 800 for heating an element of an anesthetic agent vaporizer system. For example, method 800 may be used as Figure 7 The method 800 may be performed as a portion of the method 700 (eg, at 704) to promote vaporization of the liquid anesthetic agent by heating a grid disposed within a vaporization chamber of the anesthetic agent vaporizer system and immersed in the liquid anesthetic agent. The method 800 may be performed by a controller such as Figure 2 Controller 225 or Figure 3 The controller 325 responds to the commands stored in the memory of the controller and in conjunction with one or more sensors (e.g., Figure 2 The temperature sensor 228 or Figure 3 temperature sensor 328) and an actuator (e.g., Figure 2 The heating element 208 or Figure 3 The heating element 308 is used to perform the operation.

[0111] At 802, method 800 includes receiving an indication of a type of anesthetic agent to be used. The type of anesthetic agent may refer to a specific anesthetic agent currently contained within the anesthetic agent vaporizer system (e.g., desflurane, isoflurane, or sevoflurane). In some examples, the controller may also receive an anesthetic agent concentration setpoint. The concentration setpoint may be a percentage of the vaporized anesthetic agent per volume of the fresh gas / vaporized anesthetic agent mixture to be provided to the patient (e.g., a desired concentration of the anesthetic agent delivered to the patient). The type of anesthetic agent and, in some examples, the anesthetic agent concentration setpoint may be input by a user of the controller (e.g., via Figure 2Input device 226 or Figure 3 input device 326) or obtained via another suitable mechanism.

[0112] At 804, method 800 includes determining a desired temperature (T 栅格 Similarly, the controller may also determine the desired temperature (T 液体 ). For example, each anesthetic type may have a T as a desired 栅格 The first corresponds to a predetermined temperature setting value and the desired T 液体 For example, as the boiling point of the anesthetic increases, the desired T 栅格 and the expected T 液体 The controller may input the anesthetic agent type into a lookup table stored in memory, which may output, for example, the desired T 栅格 and / or the desired T 液体 As another example, the controller may further adjust the desired T based on the anesthetic concentration set point. 栅格 and / or the desired T 液体 For example, as the anesthetic concentration setting increases, the desired T 栅格 Can be raised above a predetermined T 栅格 Similarly, as the anesthetic concentration setting increases, the desired T 液体 Can be raised above a predetermined T 液体 The controller may input the anesthetic concentration set value into one or more lookup tables, functions, or algorithms, which may output the desired T for a given anesthetic type, for example. 栅格 and / or the desired T 液体 , or for T 栅格 Setpoint and / or T 液体 Setpoint temperature regulation.

[0113] At 806, method 800 includes measuring T 栅格 The maximum power is supplied to the heating element at . Similarly, T 液体 In order to provide similar or additional information for a flexible and well-monitored heat transfer system. For example, in order to heat the grid from ambient temperature to the desired T as quickly as possible 栅格 , thereby reducing the amount of time before vaporized anesthetic can be delivered to the patient, the power source can output a maximum voltage and a maximum current to the heating element. As another example, resonant inductive coupling can be used, and the heating element can be operated at its resonant frequency to increase power transfer to the heating element, thereby producing maximum heating of the grid. For example, the maximum power can continue to be supplied to the heating element until T 栅格 Reach or approach the desired T 栅格(e.g., within a certain percentage thereof).

[0114] At 808, method 800 includes, based on the measured T 栅格 Relative to the expected T 栅格 To adjust the power supplied to the heating element. For example, the heating element may include a variable frequency drive to vary the heating element voltage (or current) and frequency, such as via pulse width modulation (PWM). As another example, the operation of the heating element may be phase shifted from the resonant frequency to reduce the heater output power. For example, the controller may be based on the desired T 栅格 , such as by placing the desired T 栅格 The drive voltage and frequency (e.g., the duty cycle of the voltage) to be supplied to the heating element may be input into a lookup table, algorithm, or function, which may output the drive voltage and frequency. The controller may then provide a voltage to the heating element at the determined drive voltage and frequency. The controller may then, for example, use a proportional-integral-derivative controller based on the measured T 栅格 Relative to the expected T 栅格 The driving voltage and frequency are further adjusted to adjust the measured T 栅格 Drive to the desired T 栅格 , as mentioned above relative to Figure 6 described.

[0115] Similarly, as T 栅格 In addition or as a substitute for 液体 Can be used for heater power control. T 液体 has multiple effects on the control variables. For example, keeping T 液体 Being at or above the maximum room temperature specification for the type of anesthetic used can improve the consistency of the amount of anesthetic delivered by the anesthetic vaporizer system. For another example, for anesthetics with relatively high vapor pressures (e.g., desflurane), controlling T 液体 The gas pressure in the vaporization chamber will be controlled. For example, when medical gas is bubbled into a liquid anesthetic (e.g., as compared to Figure 2 ), gas temperature (which may be roughly equal to T when the bubble is formed) 栅格 ) and T 液体 The difference between T and T directly controls the rate and effectiveness of reagent vapor mass delivery to the bubbles. 液体 Relative to the expected T 液体 The driving voltage and frequency are further adjusted to adjust the measured T 液体 Drive to the desired T 液体 Then, method 800 returns to continue measuring T 栅格 (and / or T 液体 ) and based on the expected T 栅格 (and / or T 液体) and the measured T 栅格 (and / or T 液体 ) is used to adjust the power supplied to the heating element until the system is deactivated and anesthetic is no longer supplied to the patient.

[0116] Therefore, the systems and methods described herein provide an induction-heated anesthetic vaporizer system. In some examples, the anesthetic vaporizer system can be a bubbling anesthetic vaporizer, in which the carrier gas bubbles and the liquid anesthetic are heated by an induction-heated grid. In other examples, such as when a low-boiling anesthetic is used, the carrier gas may not be bubbled into the anesthetic vaporizer system. By heating the grid inductively, a faster response time than boiling the anesthetic as a whole and / or using conduction heating can be provided, and a smaller amount of energy can be consumed. In addition, the temperature of the grid can be controlled in stages due to induction heating. In addition, by bubbling the gas into the induction-heated grid, the gas can become uniformly saturated with the vaporized anesthetic. In addition, a high concentration of anesthetic at a high flow rate can be maintained with a high precision and a simplified control loop.

[0117] A technical effect of immersing the induction heating grid within the liquid anesthetic agent is that the temperature of the grid can be changed rapidly while reducing power consumption to effectively vaporize the anesthetic agent.

[0118] In one embodiment, a system for an anesthesia vaporizer includes: a vaporization chamber configured to hold a liquid anesthetic; a grid disposed within the vaporization chamber; and a heating element positioned relative to the vaporization chamber and configured to increase the temperature of the grid. In a first embodiment of the system, the heating element is an induction heating element positioned outside the vaporization chamber, and the grid is composed of metal. In a second embodiment of the system, optionally including the first embodiment, the grid is completely immersed in the liquid anesthetic while operating the anesthesia vaporizer to deliver the anesthetic to a patient. A third embodiment of the system, optionally including one or both of the first and second embodiments, further includes a controller storing executable instructions in a non-transitory memory, the executable instructions, when executed, causing the controller to: adjust the amount of power provided to the heating element based on a desired temperature of the grid relative to a measured temperature of the grid and / or a desired temperature of the liquid anesthetic relative to a measured temperature of the liquid anesthetic. In a fourth embodiment of the system which optionally includes one or more or each of the first to third embodiments, the measured temperature of the grid is measured by a temperature sensor coupled to the grid, and the measured temperature of the liquid anesthetic is measured by a temperature sensor immersed in the liquid anesthetic, and the desired temperature of the grid is selected from a plurality of preset temperatures stored in a memory based on user input. In a fifth embodiment of the system that optionally includes one or more or each of the first to fourth embodiments, the instructions that cause the controller to adjust the amount of power provided to the heating element based on the expected temperature of the grid relative to the measured temperature of the grid include additional instructions stored in a non-volatile memory, which, when executed, cause the controller to: determine a drive voltage and frequency for the heating element based on the expected temperature of the grid; operate the heating element at the determined drive voltage and frequency; increase the drive voltage and frequency from the determined drive voltage and frequency in response to the measured temperature of the grid being lower than the expected temperature of the grid; and decrease the drive voltage and frequency from the determined drive voltage and frequency in response to the measured temperature of the grid being higher than the expected temperature of the grid. A sixth embodiment of the system, which optionally includes one or more or each of the first to fifth embodiments, further comprises a first gas channel configured to flow medical gas through the anesthesia vaporizer; and a first proportional valve disposed in the first gas channel and configured to control the flow rate of the medical gas through the anesthesia vaporizer.A seventh embodiment of the system, which optionally includes one or more or each of the first to sixth embodiments, further includes a second gas channel, which fluidly connects the first gas channel to the grid from downstream of the first proportional valve, the second gas channel is configured to allow a portion of the medical gas to flow from the first gas channel to the grid, and the pressure in the second gas channel is controlled by an upstream pressure regulator. An eighth embodiment of the system, which optionally includes one or more or each of the first to seventh embodiments, further includes a vapor delivery channel, which is connected between the top portion of the vaporization chamber and the first gas channel, thereby forming a joint with the first gas channel downstream of the first proportional valve to fluidly connect the top portion of the vaporization chamber with the first gas channel; a second proportional valve, which is disposed in the vapor delivery channel and is configured to control the flow rate of vapor from the vaporization chamber to the first gas channel. In a ninth embodiment of the system, which optionally includes one or more or each of the first to eighth embodiments, the controller stores additional executable instructions in a non-volatile memory, which, when executed, cause the controller to: adjust the position of one or more of the first proportional valve and the second proportional valve based on a measured anesthetic concentration relative to a desired anesthetic concentration.In a tenth embodiment of the system that optionally includes one or more or each of the first to ninth embodiments, the measured anesthetic concentration is measured by a concentration sensor connected to the first gas channel downstream of the joint, and the desired anesthetic concentration is received from a user input, and the instructions that cause the controller to adjust the position of one or more of the first proportional valve and the second proportional valve based on the measured anesthetic concentration relative to the desired anesthetic concentration include additional instructions stored in a non-volatile memory, which when executed cause the controller to: determine a first open position as a valve setting for the first proportional valve and determine a second open position as a valve setting for the second proportional valve based on the desired anesthetic concentration; operate the anesthesia system wherein the first proportional valve is commanded to the first proportional valve. the valve setting of the first proportional valve being commanded to the valve setting of the second proportional valve; in response to the measured anesthetic concentration being greater than the desired anesthetic concentration, adjusting the valve setting of the first proportional valve to a third open position, the third open position being less open than the first open position, and / or adjusting the valve setting of the second proportional valve to a fourth open position, the fourth open position being less open than the second open position; and in response to the measured anesthetic concentration being less than the desired anesthetic concentration, adjusting the valve setting of the first proportional valve to a fifth open position, the fifth open position being more open than the first open position, and / or adjusting the valve setting of the second proportional valve to a sixth open position, the sixth open position being more open than the second open position.

[0119] In another embodiment, a method for an anesthetic vaporizer includes: supplying power to an inductive heating element, the inductive heating element being configured to heat a grid disposed within a vaporization chamber of the anesthetic vaporizer, the grid being immersed in an anesthetic; and adjusting one or more valves to adjust the concentration of the anesthetic output by the anesthetic vaporizer. In a first embodiment of the method, supplying power to the inductive heating element includes: initially supplying maximum power to the inductive heating element to heat the grid from ambient temperature to a desired temperature; in response to a measured temperature of the grid reaching the desired temperature, supplying power to the inductive heating element that is less than the maximum value, the power that is less than the maximum value being determined based on the desired temperature; and further adjusting the power supplied to the inductive heating element based on a difference between the measured temperature of the grid and the desired temperature. In a second embodiment of the method that optionally includes the first embodiment, adjusting the power supplied to the induction heating element based on the difference between the measured temperature of the grid and the desired temperature includes: in response to the measured temperature being higher than the desired temperature, reducing the power supplied to the induction heating element from the power less than the maximum value; and in response to the measured temperature being lower than the desired temperature, increasing the power supplied to the induction heating element from the power less than the maximum value. In a third embodiment of the method, which optionally includes one or both of the first and second embodiments, adjusting the one or more valves to adjust the concentration of the anesthetic agent output by the anesthetic agent vaporizer includes: actuating a first proportional valve to a first position determined based on a concentration setting value, the first proportional valve being configured to adjust the gas flow entering the anesthetic agent vaporizer; actuating a second proportional valve to a second position determined based on the concentration setting value, the second proportional valve being configured to adjust the flow of the anesthetic agent vaporized in the vaporization chamber output to the gas flow; and adjusting at least one of the first proportional valve and the second proportional valve based on a difference between the concentration of the anesthetic agent output by the anesthetic agent vaporizer and the concentration setting value.

[0120] In another embodiment, a system for an anesthesia machine includes: an anesthetic vaporizer, which includes a vaporization chamber in which a mesh grid is disposed; an induction heating coil, which is arranged outside the vaporization chamber at a vertical position overlapping the vertical position of the mesh grid; a vapor delivery channel, which fluidly connects the vaporization chamber to a patient breathing circuit; a valve, which is disposed in the vapor delivery channel; and a controller, which stores executable instructions in a non-volatile memory, which when executed cause the controller to: supply power to the induction heating coil to heat the mesh grid to a temperature setting selected based on the type of anesthetic in the vaporization chamber; actuate the valve to a valve setting selected based on a desired concentration of anesthetic to be output to the patient breathing circuit; and adjust each of the power supplied to the induction heating coil and the valve setting based on corresponding electronic feedback signals. The first embodiment of the system further comprises a level sensor and a pump, the level sensor being coupled to the vaporization chamber, the level sensor being configured to measure the level of the anesthetic agent in the vaporization chamber, the pump being configured to supply the anesthetic agent from a reservoir to the vaporization chamber, and the controller storing additional executable instructions in a non-transitory memory, the executable instructions when executed causing the controller to: operate the pump to maintain the level of the anesthetic agent in the vaporization chamber within a desired range based on an output from the level sensor. In a second embodiment of the system optionally including the first embodiment, the mesh grid comprises: a central cylindrical cavity; a plurality of vertical lines radially distributed from the central cylindrical cavity to a periphery of the mesh grid in a series of equally spaced concentric sets; a plurality of horizontal lines perpendicular to the vertical lines and extending radially from the central cylindrical cavity to the periphery of the mesh grid in a series of coplanar sets; and a plurality of circular lines arranged in a plurality of concentric coplanar sets that are horizontally aligned and equally vertically distributed. In a third embodiment of the system optionally including one or both of the first and second embodiments, each circular line of the plurality of circular lines intersects a single coplanar set of all horizontal lines and a single concentric set of all vertical lines. In a fourth embodiment of the system optionally including one or more or each of the first to third embodiments, the mesh grid further includes a porous filter coupled to the central cylindrical cavity at a base of the mesh grid.

[0121] In another representation, a system for an anesthesia machine includes: an anesthetic vaporizer, the anesthetic vaporizer including a vaporization chamber; an induction heating coil, the induction heating coil arranged outside the vaporization chamber; a vapor delivery channel, the vapor delivery channel fluidly connecting the vaporization chamber to a patient breathing circuit; a valve, the valve being disposed in the vapor delivery channel; and a controller, the controller storing executable instructions in a non-volatile memory, the executable instructions, when executed, causing the controller to: supply power to the induction heating coil to heat the anesthetic within the vaporization chamber, which in some examples is based on the type of anesthetic within the vaporization chamber; actuate the valve to a valve setting selected based on a desired concentration of anesthetic to be output to the patient breathing circuit; and adjust one or more or each of the power supplied to the induction heating coil and the valve setting based on corresponding electronic feedback signals. A first embodiment of the system also includes a level sensor and a pump, wherein the level sensor is coupled to the vaporizer chamber, the level sensor being configured to measure the level of the anesthetic agent in the vaporizer chamber, the pump being configured to supply the anesthetic agent from a reservoir to the vaporizer chamber, and the controller storing additional executable instructions in a non-volatile memory, the executable instructions, when executed, causing the controller to: operate the pump to maintain the level of the anesthetic agent in the vaporizer chamber within a desired range based on an output from the level sensor.

[0122] In another representation, a system for an anesthesia vaporizer includes: a vaporization chamber configured to hold a liquid anesthetic; and a heating element positioned relative to the vaporization chamber and configured to increase the temperature of the liquid anesthetic. In a first embodiment of the system, the heating element is an induction heating element positioned outside the vaporization chamber, the vaporization chamber includes a high magnetic permeability material configured to be immersed in the liquid anesthetic, and the heating element is configured to inductively heat the liquid anesthetic. A second embodiment of the system, optionally including the first embodiment, also includes a controller storing executable instructions in a non-transitory memory, the executable instructions, when executed, causing the controller to: adjust the amount of power provided to the heating element based on a desired temperature of the high magnetic permeability material relative to a measured temperature of the high magnetic permeability material and / or a desired temperature of the liquid anesthetic relative to a measured temperature of the liquid anesthetic. In a third embodiment of the system, which optionally includes one or more or each of the first and second embodiments, the measured temperature of the liquid anesthetic is measured by a temperature sensor immersed in the liquid anesthetic, and the desired temperature of the liquid anesthetic is selected from a plurality of preset temperatures stored in a memory based on user input. In a fourth embodiment of the system, which optionally includes one or more or each of the first to third embodiments, the instructions stored in the non-transitory memory, when executed, cause the controller to: determine a drive voltage and frequency of the heating element based on the desired temperature of the high permeability material and / or liquid anesthetic; operate the heating element at the determined drive voltage and frequency; increase the drive voltage and frequency from the determined drive voltage and frequency in response to the measured temperature of the high permeability material and / or liquid anesthetic being lower than the desired temperature of the high permeability material and / or liquid anesthetic; and decrease the drive voltage and frequency from the determined drive voltage and frequency in response to the measured temperature of the high permeability material and / or liquid anesthetic being higher than the desired temperature of the high permeability material and / or liquid anesthetic. A fifth embodiment of the system, which optionally includes one or more or each of the first to fourth embodiments, further comprises a first gas channel configured to flow medical gas through the anesthesia vaporizer; and a first proportional valve disposed in the first gas channel and configured to control the flow rate of the medical gas through the anesthesia vaporizer.A sixth embodiment of the system, which optionally includes one or more or each of the first to fifth embodiments, further includes a second gas channel, which fluidly connects the first gas channel to the vaporization chamber from downstream of the first proportional valve, the second gas channel being configured to allow a portion of the medical gas to flow from the first gas channel to the vaporization chamber, and the pressure in the second gas channel is controlled by an upstream pressure regulator. A seventh embodiment of the system, which optionally includes one or more or each of the first to sixth embodiments, further includes a vapor delivery channel, which is connected between the top portion of the vaporization chamber and the first gas channel, thereby forming a joint with the first gas channel downstream of the first proportional valve to fluidly connect the top portion of the vaporization chamber with the first gas channel; a second proportional valve, which is disposed in the vapor delivery channel and is configured to control the flow rate of vapor from the vaporization chamber to the first gas channel. In an eighth embodiment of the system, which optionally includes one or more or each of the first to seventh embodiments, the controller stores additional executable instructions in a non-volatile memory, which, when executed, cause the controller to: adjust the position of one or more of the first proportional valve and the second proportional valve based on the measured anesthetic concentration relative to the desired anesthetic concentration.In a ninth embodiment of the system that optionally includes one or more or each of the first to eighth embodiments, the measured anesthetic concentration is measured by a concentration sensor connected to the first gas channel downstream of the joint, and the desired anesthetic concentration is received from a user input, and the instructions that cause the controller to adjust the position of one or more of the first proportional valve and the second proportional valve based on the measured anesthetic concentration relative to the desired anesthetic concentration include additional instructions stored in a non-volatile memory, which when executed cause the controller to: determine a first open position as a valve setting for the first proportional valve and determine a second open position as a valve setting for the second proportional valve based on the desired anesthetic concentration; operate the anesthesia system wherein the first proportional valve is commanded to the first proportional valve. the valve setting of the first proportional valve being commanded to the valve setting of the second proportional valve; in response to the measured anesthetic concentration being greater than the desired anesthetic concentration, adjusting the valve setting of the first proportional valve to a third open position, the third open position being less open than the first open position, and / or adjusting the valve setting of the second proportional valve to a fourth open position, the fourth open position being less open than the second open position; and in response to the measured anesthetic concentration being less than the desired anesthetic concentration, adjusting the valve setting of the first proportional valve to a fifth open position, the fifth open position being more open than the first open position, and / or adjusting the valve setting of the second proportional valve to a sixth open position, the sixth open position being more open than the second open position.

[0123] In another representation, a method for an anesthetic vaporizer includes: supplying power to an inductive heating element, the inductive heating element being configured to heat a liquid anesthetic disposed within a vaporization chamber of the anesthetic vaporizer; and adjusting one or more valves to adjust a concentration of the anesthetic output by the anesthetic vaporizer. In a first embodiment of the method, supplying power to the inductive heating element includes: initially supplying a maximum power to the inductive heating element to heat the liquid anesthetic from an ambient temperature to a desired temperature; in response to a measured temperature of the liquid anesthetic reaching the desired temperature, supplying a power less than the maximum value to the inductive heating element, the power less than the maximum value being determined based on the desired temperature; and further adjusting the power supplied to the inductive heating element based on a difference between the measured temperature of the liquid anesthetic and the desired temperature. In a second embodiment of the method that optionally includes the first embodiment, adjusting the power supplied to the induction heating element based on the difference between the measured temperature and the desired temperature of the liquid anesthetic comprises: in response to the measured temperature being higher than the desired temperature, reducing the power supplied to the induction heating element from the power less than the maximum value; and in response to the measured temperature being lower than the desired temperature, increasing the power supplied to the induction heating element from the power less than the maximum value. In a third embodiment of the method, which optionally includes one or both of the first and second embodiments, regulating the one or more valves to regulate the concentration of the anesthetic agent output by the anesthetic agent vaporizer comprises: actuating a first proportional valve to a first position determined based on a concentration setpoint, the first proportional valve configured to regulate a gas flow entering the anesthetic agent vaporizer; actuating a second proportional valve to a second position determined based on the concentration setpoint, the second proportional valve configured to regulate a flow of the anesthetic agent vaporized in the vaporization chamber output to the gas stream; and regulating at least one of the first proportional valve and the second proportional valve based on a difference between the concentration of the anesthetic agent output by the anesthetic agent vaporizer and the concentration setpoint. In a fourth embodiment of the method, which optionally includes one or more or each of the first to third embodiments, supplying power to an inductive heating element configured to heat a liquid anesthetic agent disposed within a vaporization chamber of the anesthetic agent vaporizer comprises supplying power to the inductive heating element to heat a high magnetic permeability material immersed in the liquid anesthetic agent disposed within the vaporization chamber of the anesthetic agent vaporizer.

[0124] As used herein, the elements or steps listed in the singular and beginning with the word "one" or "a kind of" should be understood as not excluding a plurality of the elements or steps, unless such exclusion is explicitly stated. In addition, the reference to "an embodiment" of the present invention is not intended to be interpreted as excluding the existence of additional embodiments that also include the cited features. In addition, unless explicitly stated to the contrary, the embodiment of "including", "comprising" or "having" an element or multiple elements with a specific characteristic may include additional such elements without the characteristic. The terms "including" and "in..." are used as the concise language equivalents of the corresponding terms "including" and "wherein". In addition, the terms "first", "second" and "third" etc. are only used as marks, and are not intended to impose numerical requirements or specific positional order on their objects.

[0125] This written description uses examples to disclose the invention, including the best mode, and also to enable a person of ordinary skill in the relevant art to practice the invention, including making and using any devices or systems and performing any included methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person of ordinary skill in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insignificant differences from the literal language of the claims.

Claims

1. A system for an anesthesia vaporizer, comprising: a vaporization chamber configured to hold a liquid anesthetic agent; a grid, the grid being disposed in the gasification chamber; a heating element positioned relative to the vaporization chamber and configured to increase a temperature of the grid; a first gas passage configured to flow a medical gas through the anesthesia vaporizer; and A second gas channel is configured to allow a portion of the medical gas to flow from the first gas channel to the grid via a bottom of the gasification chamber.

2. The system of claim 1, wherein the heating element is an induction heating element positioned outside of the vaporization chamber and the grid is comprised of metal.

3. The system of claim 1, wherein the grid is completely immersed in the liquid anesthetic agent while the anesthetic vaporizer is operated to deliver anesthetic agent to a patient.

4. The system of claim 1 , further comprising a controller storing executable instructions in a non-transitory memory, the executable instructions when executed causing the controller to: The amount of power provided to the heating element is adjusted based on a desired temperature of the grid relative to the measured temperature of the grid and / or a desired temperature of the liquid anesthetic agent relative to the measured temperature of the liquid anesthetic agent.

5. The system of claim 4, wherein the measured temperature of the grid is measured by a temperature sensor coupled to the grid, and the measured temperature of the liquid anesthetic is measured by a temperature sensor immersed in the liquid anesthetic, and the desired temperature of the grid is selected from a plurality of preset temperatures stored in a memory based on user input.

6. The system of claim 4, wherein the instructions that cause the controller to adjust the amount of power provided to the heating element based on the desired temperature of the grid relative to the measured temperature of the grid include additional instructions stored in non-transitory memory that, when executed, cause the controller to: determining a driving voltage and frequency for the heating element based on the desired temperature of the grid; operating the heating element at the determined drive voltage and frequency; In response to the measured temperature of the grid being lower than the desired temperature of the grid, increasing the drive voltage and frequency from the determined drive voltage and frequency; as well as In response to the measured temperature of the grid being higher than the desired temperature of the grid, the drive voltage and frequency are reduced from the determined drive voltage and frequency.

7. The system according to claim 4, further comprising: A first proportional valve is disposed in the first gas passage and is configured to control a flow rate of the medical gas through the anesthesia vaporizer.

8. The system of claim 7, wherein the second gas passage fluidly couples the first gas passage to the grid from downstream of the first proportional valve, the pressure in the second gas passage being controlled by an upstream pressure regulator.

9. The system according to claim 7, further comprising: a vapor delivery passage coupled between a top portion of the vaporization chamber and a first gas passage to form a junction with the first gas passage downstream of the first proportional valve to fluidly couple the top portion of the vaporization chamber with the first gas passage; A second proportional valve is disposed within the vapor delivery passage and is configured to control a flow rate of vapor from the vaporization chamber to the first gas passage.

10. The system of claim 9, wherein the controller stores further executable instructions in the non-transitory memory, the executable instructions when executed causing the controller to: The position of one or more of the first and second proportional valves is adjusted based on the measured anesthetic concentration relative to a desired anesthetic concentration.

11. The system of claim 10, wherein the measured anesthetic concentration is measured by a concentration sensor coupled to the first gas passage downstream of the junction and the desired anesthetic concentration is received from a user input, and wherein the instructions to cause the controller to adjust the position of one or more of the first and second proportional valves based on the measured anesthetic concentration relative to the desired anesthetic concentration include additional instructions stored in non-transitory memory that, when executed, cause the controller to: determining a first open position as a valve setting of the first proportional valve and determining a second open position as a valve setting of the second proportional valve based on the desired anesthetic agent concentration; operating an anesthesia system wherein the first proportional valve is commanded to the valve setting of the first proportional valve and the second proportional valve is commanded to the valve setting of the second proportional valve; In response to the measured anesthetic agent concentration being greater than the desired anesthetic agent concentration, adjusting the valve setting of the first proportional valve to a third open position, the third open position being less open than the first open position, and / or adjusting the valve setting of the second proportional valve to a fourth open position, the fourth open position being less open than the second open position; and In response to the measured anesthetic concentration being less than the desired anesthetic concentration, the valve setting of the first proportional valve is adjusted to a fifth open position, the fifth open position being more open than the first open position, and / or the valve setting of the second proportional valve is adjusted to a sixth open position, the sixth open position being more open than the second open position.

12. A method for an anesthetic vaporizer, comprising: supplying power to an induction heating element, the induction heating element being configured to heat a grid disposed within a vaporization chamber of the anesthetic agent vaporizer, the grid being immersed in an anesthetic agent; adjusting one or more valves to adjust the concentration of the anesthetic agent output by the anesthetic agent vaporizer; allowing a medical gas to flow through the anesthetic agent vaporizer through a first gas passage; as well as A portion of the medical gas is caused to flow from the first gas channel through the bottom of the gasification chamber to the grid through the second gas channel.

13. The method of claim 12, wherein supplying power to the induction heating element comprises: initially supplying maximum power to the induction heating element to heat the grid from ambient temperature to a desired temperature; In response to the measured temperature of the grid reaching the desired temperature, supplying less than a maximum power to the inductive heating element, the less than maximum power being determined based on the desired temperature; as well as Power supplied to the inductive heating element is further adjusted based on a difference between the measured temperature of the grid and the desired temperature.

14. The method of claim 13, wherein adjusting the power supplied to the inductive heating element based on the difference between the measured temperature of the grid and the desired temperature comprises: In response to the measured temperature being greater than the desired temperature, reducing power supplied to the inductive heating element from the power less than the maximum value; as well as In response to the measured temperature being lower than the desired temperature, the power supplied to the inductive heating element is increased from the less-than-maximum power.

15. The method of claim 12, wherein adjusting the one or more valves to adjust the concentration of the anesthetic agent output by the anesthetic agent vaporizer comprises: actuating a first proportional valve to a first position determined based on a concentration setpoint, the first proportional valve being configured to regulate a flow of gas into the anesthetic agent vaporizer; actuating a second proportional valve to a second position determined based on the concentration set point, the second proportional valve being configured to regulate a flow rate of the anesthetic agent vaporized in the vaporization chamber output to the gas stream; as well as At least one of the first proportional valve and the second proportional valve is adjusted based on a difference between the concentration of the anesthetic agent output by the anesthetic agent vaporizer and the concentration set value.

16. A system for an anesthesia machine, comprising: an anesthetic agent vaporizer, the anesthetic agent vaporizer comprising a vaporization chamber having a mesh grid disposed therein; an induction heating coil disposed outside the vaporization chamber at a vertical position overlapping a vertical position of the mesh grid; a vapor delivery passageway fluidly coupling the vaporization chamber to a patient breathing circuit; a valve disposed in the vapor delivery passage; and A controller storing executable instructions in a non-transitory memory, the executable instructions, when executed, causing the controller to: supplying power to the induction heating coil to heat the mesh grid to a temperature set point selected based on a type of anesthetic agent within the vaporization chamber; actuating the valve to a valve setting selected based on a desired concentration of anesthetic agent to be output to the patient breathing circuit; and regulating each of the power supplied to the induction heating coil and the valve setting based on corresponding electronic feedback signals; allowing a medical gas to flow through the anesthetic agent vaporizer through a first gas passage; as well as A portion of the medical gas is caused to flow from the first gas passage through the bottom of the gasification chamber to the mesh grid through the second gas passage.

17. The system of claim 16, further comprising a level sensor coupled to the vaporizer chamber, the level sensor configured to measure a level of the anesthetic agent in the vaporizer chamber, and a pump configured to supply the anesthetic agent from a reservoir to the vaporizer chamber, and wherein the controller stores additional executable instructions in the non-transitory memory that, when executed, cause the controller to: The pump is operated to maintain the level of the anesthetic agent in the vaporization chamber within a desired range based on the output from the level sensor.

18. The system of claim 16, wherein the mesh grid comprises: central cylindrical cavity; a plurality of vertical lines radially distributed from the central cylindrical cavity to the periphery of the mesh grid in a series of equally spaced concentric sets; a plurality of horizontal lines perpendicular to the vertical lines and extending radially from the central cylindrical cavity to the perimeter of the mesh grid in a series of coplanar sets; and A plurality of circular lines are arranged in a plurality of concentric coplanar sets that are horizontally aligned and equally distributed vertically.

19. The system of claim 18, wherein each circular line of the plurality of circular lines intersects a single coplanar set of all of the horizontal lines and a single concentric set of all of the vertical lines.

20. The system of claim 18, wherein the mesh grid further comprises a porous filter coupled to the central cylindrical cavity at a base of the mesh grid.

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