Valve module, and method for influencing flow properties of a respiratory gas flow

Abstract

The invention relates to a valve module (1, 30) for a ventilator (40) for influencing flow properties of a respiratory gas flow, the valve module comprising: a flow channel (3) in which a valve (2) is arranged, the flow channel (3) having an inlet (4) and an outlet (5) which can be fluidically connected to the ventilator (40); and a first flow rate sensor (6) for measuring a flow rate in the flow channel (3), characterised in that at least one further flow rate sensor (7) for measuring a flow rate in the flow channel (3) is provided, and the valve (2) can be controlled taking into account a setpoint value, a measurement value of the first flow rate sensor, a measurement value of the at least one further flow rate sensor, and a module characteristic map (10) generated prior to intended use, the module characteristic map (10) comprising at least measurement values detected by the first flow rate sensor (6) and by the at least one further flow rate sensor (7). The invention also relates to a ventilator (40) comprising a valve module (1, 30) and to a method.

Description

[0001] Valve module and method for influencing the flow characteristics of a breathing gas stream

[0002] Description

[0003] The present invention relates to a valve module and a method for influencing the flow characteristics of a respiratory gas flow in a ventilator and a ventilator with a valve module.

[0004] Ventilators are used to support or take over the respiratory effort of a patient and can be designed as a standalone device for patient ventilation or in combination with an anesthesia machine, since the patient's respiratory drive is often suspended during anesthesia. The purpose of the ventilator is to supply the patient with sufficient oxygen and to support the removal of carbon dioxide from the lungs. To supply the patient with oxygen, the ventilator provides a breathing gas flow, which typically consists of oxygen and air. In combination with an anesthesia machine, the breathing gas flow can include other components, particularly anesthetic gases such as nitrous oxide. The breathing gas flow is adjusted to the patient's needs, with the oxygen concentration and / or anesthetic gas concentration, the volume flow rate, and / or the pressure of the breathing gas flow being specifically adjustable.

[0005] The adaptation of the respiratory gas flow to the patient's needs is typically achieved using a controllable valve, which influences the characteristics of the respiratory gas flow through different valve gap positions. The valve is usually controlled by a system where at least one setpoint value is specified and at least one actual value is determined for each parameter to be controlled. Often, the volumetric flow rate of the respiratory gas flow is to be regulated, with the volumetric flow rate measured downstream of the valve and used as the actual value. A volumetric flow sensor is positioned accordingly. With the valve as the actuator and the volumetric flow sensor, the respiratory gas flow can be regulated.

[0006] The measurement principles of a volumetric flow sensor are based, for example, on heat transfer, ultrasonic velocity, or pressure drop. Such measurement principles are susceptible to non-harmonic flows, i.e., uneven flows that include, for example, turbulent or non-laminar flow components, which can distort the measurement result. Non-harmonic flow is often caused by the valve, which influences the properties, particularly the volumetric flow rate, of a breathing gas stream. A fully open valve generates a high volumetric flow rate, while a nearly closed valve, with a very small valve gap, generates a low volumetric flow rate. Within the valve, the breathing gas stream is deflected multiple times until it exits the valve gap. These deflections cause the breathing gas stream, especially at high volumetric flow rates, to contain non-harmonic pulses that complicate the measurement of the volumetric flow rate.Furthermore, smaller flow rates with a small valve gap can generate high flow velocities in the breathing gas stream, leading to uneven flow. For this reason, prior art employs measures to smooth the non-harmonic flow, at least to the extent necessary to ensure sufficient measurement quality from the flow sensor. Typically, calming sections are used, where the flow channel between the valve and the flow sensor is lengthened, allowing the breathing gas flow to smooth out as it passes through the calming section and enabling a more accurate flow rate measurement. Such a calming section requires more installation space due to the extended flow channel.The settling section often has a cross-section approximately ten times that of the flow channel at the valve outlet to equalize the breathing gas flow, thus enabling accurate volumetric flow measurement. The installation space is thereby increased by at least this amount. Based on solutions known from the prior art and the problems described above, the invention aims to provide a valve module and a method for influencing the flow characteristics of a breathing gas flow, which has a compact design and is easily controllable.

[0007] The foregoing problem is solved by a valve module having the features of claim 1, a ventilator with a valve module according to claim 12, and a method according to claim 13. Further details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the valve module according to the invention also apply in connection with the ventilator and the method according to the invention, so that, with regard to the disclosure of the individual aspects of the invention, mutual reference is always made, or rather, can be made.

[0008] The valve module according to the invention for a ventilator for influencing the flow characteristics of a respiratory gas stream comprises a flow channel in which a valve is arranged. The flow channel has an inlet and an outlet that can be connected to the ventilator via fluid communication. Furthermore, the valve module comprises a first volume flow sensor for measuring a volume flow in the flow channel. The valve module according to the invention is characterized in that at least one further volume flow sensor is provided for measuring a volume flow in the flow channel and the valve can be controlled taking into account a predetermined or stored setpoint, a measured value from the first volume flow sensor, a measured value from the at least one further volume flow sensor, and a module characteristic map generated before the intended use of the valve module.The module characteristic map contains a plurality of values ​​and includes measured values ​​acquired at least with the first volume flow sensor and with at least one further volume flow sensor.

[0009] The majority of values ​​are added to the module's characteristic curve before the valve module is put into operation, i.e., before its intended use. Preferably, the majority of these values ​​are generated by the manufacturer after the production process and before the valve module is used productively in the ventilator, and then added to the module's characteristic curve.

[0010] The valve module is suitable for integration into a ventilator and an anesthesia machine with a ventilation function. In the following text, only the term "ventilator" is used, which refers to both ventilators and anesthesia machines with a ventilation function.

[0011] The valve module is designed to modify the flow characteristics, particularly the volumetric flow rate, of the breathing gas stream. The valve, especially an inspiratory valve, comprises a valve element movable by a valve actuator. The valve gap, and thus the cross-section of the flow channel through which the breathing gas flows, can be modified by initiating movement of the valve element based on a control signal transmitted to the valve actuator. It is conceivable that the valve actuator is located outside the valve and the valve module and has a connection to the valve module for controlling the valve, or that it is a component of the valve module or the valve itself.The valve or valve actuator is controlled by a control unit, which may also be located outside the valve module and has a wireless or wired electronic connection for transmitting signals and / or data to the valve or valve actuator. Alternatively, and preferably, the valve module includes the control unit. The control unit preferably comprises at least one microprocessor or comparable processing unit and at least one data storage device.

[0012] The flow channel of the valve module has an inlet that can be connected to a ventilator, in particular to a pressure source of the ventilator, via a suitable interface element, for example, a plug-in mechanism or a screw cap, in a fluid-communicating and preferably airtight manner. The pressure source can be a gas cylinder, a central gas supply of a hospital, or preferably a blower of the ventilator, wherein the blower draws in air from the environment of the ventilator and directs it to the valve module. During normal operation, a breathing gas or a breathing gas mixture from the ventilator flows into the valve module through the inlet; this gas can be air, gas, and / or a gas or air-gas mixture.Furthermore, the flow channel has an outlet which can be connected to the ventilator via a suitable interface element, for example via a plug-in mechanism or a screw cap, and through which the breathing gas flows during operation.

[0013] To influence the flow characteristics of the breathing gas stream, particularly for control purposes, the volumetric flow rate of the breathing gas stream is measured by at least two volumetric flow sensors within the valve module. Volumetric flow sensors and mass flow sensors are to be considered equivalent in the context of the invention. In ventilation technology, the term volumetric flow sensor is commonly used. The volumetric flow sensor or the mass flow sensor measures how much volume or mass of a fluid, in this case a breathing gas, flows through the flow channel per unit of time.

[0014] The first and at least one subsequent volumetric flow sensor preferably have the same design. Volumetric flow sensors have the advantage of a comparatively high dynamic range and are suitable for measuring small volumetric flow rates as well as rapid changes in volumetric flow rate. In contrast, pressure sensors, for example, which are also suitable for determining volumetric flow rates, have a significantly lower dynamic range and, in particular, large inaccuracies at small volumetric flow rates.

[0015] The valve module is controlled by taking into account the setpoint, the measured values ​​of the first and at least one additional flow sensor, and the module characteristic curve described in more detail below. The setpoint, in particular, represents information about a target flow rate, which is set by the valve module, specifically by appropriately adjusting the valve and thus changing the valve gap. The setpoint is specified, for example, by a user of the ventilator in which the valve module is integrated, via a control unit, or it is transmitted to the ventilator and / or the valve module via a data interface. The output values ​​of the flow sensors are, for example, analog voltage values, analog current values, or numerical digital values ​​and represent the measured values ​​of the respective flow sensor, which change when the flow rate of the respiratory gas changes.

[0016] The module characteristic map, generated prior to the intended use of the valve module, comprises multiple measured values ​​from the first and at least one additional volume flow sensor for respiratory gas flows with varying flow characteristics, particularly different volume flows. These measured values ​​are acquired prior to the intended use of the valve module, especially prior to its integration into a ventilator, for example, directly after the valve module's manufacture. Several measured values ​​from each volume flow sensor are acquired for different valve positions, resulting in varying respiratory gas flows within the flow channel, and stored in the module characteristic map. Preferably, the valve gap is initially closed completely and then gradually opened at preferably uniform intervals until the valve gap is fully open.The changes to the valve gap must be determined according to the accuracy requirements of the application.

[0017] The module characteristic map further includes volume flow values ​​of the valve module, which are preferably recorded by an external measuring device for measuring the valve module before the intended use of the valve module and preferably simultaneously with, or for the same valve position as, the measured values ​​of the first and at least one further volume flow sensor. The external measuring device comprises at least one volume flow sensor and is preferably fluidly connected to the outlet of the flow channel of the valve module via an external flow channel serving as a calming section for the breathing gas flow.The measured values ​​of the first and at least one further volume flow sensor are each linked to a volume flow value of the preferably external volume flow sensor in the module characteristic map, so that the module characteristic map shows a dependency relationship between the volume flow values ​​of the valve module and the measured values ​​of the first and at least one further volume flow sensor. In the simplest case, the module characteristic map comprises a table with the volume flow values ​​of the valve module and the measured values ​​of the first and at least one further volume flow sensor, wherein the values ​​for a respective measurement time and / or for a respective valve position are arranged in one row.

[0018] It is also conceivable that the volume flow values ​​of the valve module could alternatively be determined by simulation with a model of the valve module and / or that the volume flow values ​​of the valve module could be adjusted by simulation with a model of the valve module, machine learning, artificial intelligence, and / or by using a digital twin of the valve module. For example, data from previously created module characteristic maps of other valve modules and the properties of a particular valve module could be used as training data for an algorithm to create or improve a module characteristic map. This advantageously accelerates the creation of a module characteristic map for a valve module, as no or at least fewer measurements need to be carried out with the valve module before its intended use.

[0019] Furthermore, it is conceivable that the aforementioned acquisition of values ​​for the module characteristic map is also carried out for breathing gas flows with different compositions and / or that the values ​​are acquired under different environmental conditions and / or for other different properties of the breathing gas flow, such as temperature, pressure, or humidity. These different compositions, environmental conditions, and other properties of the breathing gas flow are also recorded during the creation of the module characteristic map and added to the map accordingly. Thus, these values ​​can be taken into account during the intended operation of the valve module, enabling even better control of the breathing gas flow by the valve module.This includes appropriate components, in particular additional sensors for, for example, temperature and pressure in the valve module and / or ventilator, so that their measured values ​​can be referenced in the module's characteristic map and taken into account when changing the valve.

[0020] The module characteristic map is generated individually for each valve module, preferably for a production batch of a valve module or, more preferably, for a series of valve modules. The purpose of the module characteristic map is to illustrate the relationship between the valve and the flow channel and the first and at least one additional volume flow sensor for the respective valve module. This relationship arises from the respective properties of the valve, the flow channel geometry, and the arrangement of the volume flow sensors. Advantageously, these relationships are represented in the module characteristic map and do not need to be individually considered when controlling the valve module to influence the breathing gas flow, thus significantly simplifying the control of the valve module.

[0021] To control at least one characteristic of the respiratory gas flow, particularly the volumetric flow rate, the setpoint (preferably the target volumetric flow rate) and the actual value (preferably the measured actual volumetric flow rate) are of particular importance. The setpoint, especially the target volumetric flow rate, is specified, for example, by a user of the ventilator. For precise control, the actual volumetric flow rate should also be as accurate as possible. The actual volumetric flow rate of the valve module is determined from the measured values ​​of the first and at least one additional volumetric flow sensor and the module characteristic map generated before the valve module is used as intended. The currently acquired measured values ​​of the volumetric flow sensors are, as described above, encompassed by the module characteristic map and can each be assigned to a volumetric flow rate value of the valve module.It is also conceivable, particularly if the current measured values ​​are not included in the module map, that the nearest measured value in the module map can be assigned to the current measured value. Furthermore, it is conceivable that the current measured value can be assigned to a volume flow value of the valve module by interpolating the measured values ​​of the module map. In any case, the current measured value of the first and at least one further volume flow sensor can each be assigned to a measured value in the module map.

[0022] By assigning the currently recorded measured values ​​from the first and at least one further volume flow sensor to the respective values ​​of the module characteristic map, one volume flow value, or at least two volume flow values ​​if the measured values ​​are assigned different volume flow values ​​in the module characteristic map, can be determined. In the simplest case, and particularly with a single determined volume flow value from the module characteristic map, this value is to be considered as the actual volume flow in the control system. In the case of several determined volume flow values, the largest or, preferably, the average of the several determined volume flow values ​​is to be considered as the actual volume flow value in the control system. Particularly preferably, the module characteristic map includes a weighting factor for the respective measured values, wherein the actual volume flow is obtained by multiplying the determined volume flow value or the several determined volume flow values ​​by the respective weighting factor.The weighting factors are also determined before the valve module is used as intended by analyzing the measured values ​​of the module's characteristic curve and relating them to the properties of the valve module, in particular the arrangement of the volume flow sensors. The weighting factors preferably indicate the extent to which the respective measured value contributes to the actual volume flow of the valve module. Taking into account the determined actual volume flow and the setpoint, in particular a target volume flow, a control signal for the valve and / or the valve actuator can be determined by the control unit, which allows the breathing gas flow to be changed according to the setpoint.Preferably, the control unit compares the setpoint with the actual volume flow and generates and transmits a corresponding control signal for the valve, in particular for the valve actuator, so that the valve module influences the breathing gas flow in such a way that the actual volume flow of the breathing gas flow corresponds at least almost to the setpoint.

[0023] The valve module, as previously described, can be controlled in a straightforward manner, requiring only a few calculations and eliminating the need to incorporate complex dependency relationships into the control algorithm. Furthermore, the valve module boasts a particularly compact design, as no calming section is required to harmonize the respiratory gas flow. Another advantage is the simple integration of the valve module into a ventilator, requiring only mechanical connection of the inlet and outlet, and, depending on the valve module's design, the valve and flow rate sensors. For example, the valve module can be mechanically connected to the ventilator using one or more snap-in mechanisms, screws, adhesive bonding, and / or welding.

[0024] According to a preferred embodiment of the valve module, the valve is designed as a low-pressure valve or as a high-lumen low-pressure valve.

[0025] The low-pressure valve is designed to meter fluids, particularly breathing gases, at pressures up to 500 mbar (equivalent to 50,000 Pa) and exhibits particularly high accuracy in metering a breathing gas flow. The high-lumen low-pressure valve preferably has a cross-sectional area of ​​at least 12 mm². 2 and / or have a diameter of at least 4 mm. Particularly preferably, especially when the valve module is configured for a ventilator suitable for adult patients, the high-lumen, low-pressure valve has a cross-sectional area of ​​80 mm². 2and / or have a diameter of at least 10 mm. In ventilation technology, low-pressure valves are particularly advantageous, especially for influencing the flow of respiratory gases, as they allow for particularly precise and rapid metering of the respiratory gas flow.

[0026] In a preferred embodiment of the valve module, the first volume flow sensor and the at least one further volume flow sensor are arranged such that they at least temporarily record different measured values, wherein the volume flow of the respiratory gas flow to be measured at a respective measuring point of the first volume flow sensor and the at least one further volume flow sensor is influenced by the geometry of the flow channel.

[0027] The first and at least one subsequent flow sensor record measurements of the breathing gas flow in the flow channel at least nearly simultaneously and / or at equal time intervals. In practice, the recorded measurements often differ, at least to a small extent, regardless of the arrangement of the flow sensors, because the flow sensors are not ideal and even exhibit manufacturing and / or assembly-related variations. This also applies when the flow sensors are of identical construction. Such differences in the measured values, which are usually small, are not relevant in this context and are often negligible in practice.Rather, in this preferred embodiment, differences in the measured values ​​of the volume flow sensors in the valve module are brought about by the special arrangement of the first and at least one further volume flow sensor, wherein the differences in the measured values ​​in connection with the knowledge of the arrangement of the respective sensor make it possible to determine the actual volume flow of the breathing gas flow in an advantageous way.

[0028] The flow characteristics of the breathing gas stream in the flow channel vary, at least in part, from section to section and depend on the geometry of the flow channel. The first and at least one subsequent volume flow sensor are arranged within the valve module and in the flow channel such that their readings are as different as possible from each other when the breathing gas stream remains constant, i.e., when the valve position remains constant. The greater the difference between the readings of the first and at least one subsequent volume flow sensor, the less redundancy the readings exhibit. This specific arrangement of the first and at least one subsequent volume flow sensor in the valve module allows for the measurement of different volume flow values ​​of the breathing gas stream. For example, for a first breathing gas stream, the reading of the first volume flow sensor is higher than the reading of the second volume flow sensor.Furthermore, for example, for a second breathing gas flow at a higher pressure, the reading from the first flow sensor is lower than the reading from the second flow sensor. This example shows that the relationship between the readings of the different flow sensors changes depending on the breathing gas flow. This relationship is depicted in the module characteristic map, where readings from the flow sensors were recorded for various breathing gas flows before the valve module was used as intended.

[0029] The previously described differences in the measured values ​​of the volumetric flow sensors and their relationships to each other represent a specific characteristic of the valve module. This characteristic provides information about the flow properties of the breathing gas flow prevailing in the flow channel and can be advantageously used to determine the volumetric flow rate of the valve module, in particular the actual volumetric flow rate. The characteristic of the valve module is depicted in the module characteristic map.

[0030] Preferably, the first flow sensor is arranged upstream of the valve in the flow direction, and the at least one further flow sensor is arranged downstream of the valve in the flow direction. Particularly preferably, the first flow sensor and the at least one further flow sensor are arranged in the area of ​​a deflection of the breathing gas flow, for example, in a bend of the flow channel. Furthermore, preferably, the first flow sensor and the at least one further flow sensor are arranged in the area of ​​a flow resistance in the flow channel or a constriction of the flow channel. In all the above cases, the first flow sensor and the at least one further flow sensor are arranged at those locations in the flow channel where the flow characteristics, in particular the flow rate, differ.This difference, which is reflected in the measured values ​​of the volume flow sensors, shows the characteristics of the respective valve module and can be advantageously used to determine an accurate actual volume flow of the valve module.

[0031] According to a preferred embodiment of the valve module, the first flow sensor and at least one further flow sensor are arranged in the immediate vicinity of the valve, with each flow sensor being located upstream or, preferably, downstream of the valve in the flow direction. The distance between the valve and each flow sensor is less than 0.05 m, preferably less than 0.04 m, and particularly preferably less than 0.03 m. Furthermore, the distance is preferably less than twice the cross-sectional area of ​​the flow channel of the valve module. Advantageously, a valve module with flow sensors arranged in the immediate vicinity of the valve is particularly compact and requires little installation space, especially when integrated into a ventilator.

[0032] In a preferred embodiment of the valve module, the first flow sensor and / or at least one further flow sensor are arranged on an inner wall of the flow channel. Particularly preferably, the flow sensors are permanently attached to the inner wall of the flow channel in a way that prevents damage, thus ensuring a secure and lasting hold. This embodiment features a simple design that can be implemented with minimal effort. According to a preferred embodiment of the valve module, the first flow sensor and / or at least one further flow sensor are arranged in a bypass of the flow channel.

[0033] The bypass is an extension and / or branch of the flow channel and can be specifically adapted to the requirements of the respective volumetric flow sensor or to the application needs. This advantageously further improves the measurement quality of the respective volumetric flow sensor.

[0034] In a preferred embodiment of the valve module, the flow channel has at least a partial curvature. Furthermore, the first volume flow sensor and / or at least one additional volume flow sensor are arranged within a region of the flow channel's curvature. Due to the curvature of the flow channel, the breathing gas flow is deflected and exhibits locally different characteristics. For example, near the outermost apex of the curvature, there is an increased prevalence of partial flows of the breathing gas flow with high flow velocities, whereas partial flows of the breathing gas flow with low flow velocities are more prevalent in the flow direction towards the end of the curvature. The volume flow rates measured at the various locations differ for the partial flows of the breathing gas flow. Preferably, the volume flow sensors are arranged at these locations within the flow channel.Advantageously, the first and / or at least one further volume flow sensor can be arranged in the area of ​​the curvature of the flow channel in such a way that the different volume flows of the breathing gas flow can be detected and an actual volume flow of the valve module can be determined with these measured values.

[0035] According to a preferred embodiment, the valve module includes a pressure sensor configured to detect a pressure reading in the flow channel upstream of the valve. Furthermore, according to this embodiment, the valve can be controlled based on this pressure reading. The pressure of the breathing gas acts on the valve element, particularly a valve diaphragm, which is affected at high pressures because the pressure opposes the valve element during closing. By taking the pressure value into account during control by the control unit, its influence can be compensated for, and the breathing gas flow can be advantageously controlled more easily and precisely.

[0036] In a preferred embodiment, the valve module comprises a control unit configured to generate a control signal for the targeted adjustment of the valve, taking into account the setpoint, the measured value of the first volume flow sensor, the measured value of at least one further volume flow sensor, and the module characteristic curve. In this embodiment, the control unit is integrated into the valve module. For wireless and / or wired data exchange with the control unit, the valve module includes a suitable communication interface. Thus, for example, data from a ventilator, in particular the module characteristic curve and the set volume flow, can be received by the control unit, and data, in particular status information and / or measured values, can be transmitted to the ventilator. Advantageously, the valve module, which includes the control unit, can be integrated into a ventilator particularly easily.Furthermore, it simplifies the application of the valve module.

[0037] In a preferred embodiment of the valve module, the first flow sensor and / or at least one further flow sensor are designed as heat flux sensors. Heat flux sensors are particularly reliable and offer good measurement accuracy, especially for small flow rates. Furthermore, heat flux sensors can be implemented without significant effort.

[0038] Preferably, the first volumetric flow sensor configured as a heat flux sensor and / or the at least one further volumetric flow sensor configured as a heat flux sensor comprise a heating wire, a microelectromechanical system (MEMS), a heating resistor, or a structured film with a microelectromechanical system. MEMS heat flux sensors, for example as a sensor array using CMOS (complementary metal-oxide semiconductor) technology, are particularly preferred.

[0039] According to the invention, a ventilator is proposed that includes a valve module according to at least one previously described embodiment. A target volume flow rate can be set on the ventilator. The target volume flow rate is transmitted to the control unit, which is included by the ventilator or the valve module, and the control unit controls the valve, as described above, so that the target volume flow rate corresponds at least almost exactly to the actual volume flow rate of the valve module.

[0040] The invention further presents a method for controlling a valve of a ventilator, which is suitable for influencing the flow characteristics of a respiratory gas stream. A valve module is provided that includes a flow channel with the valve, as well as a first volume flow sensor and at least one further volume flow sensor for measuring the volume flow of the respiratory gas stream. A control signal for the targeted adjustment of the valve is generated, taking into account a setpoint and a measured value from the first volume flow sensor. The method is characterized in that the control signal is further generated taking into account a measured value from the at least one further volume flow sensor and a module characteristic map, wherein the module characteristic map is generated before the intended use of the valve module and includes measured values ​​generated by at least the first sensor and the at least one further sensor.

[0041] In one step of the process, a target flow rate is received. This target flow rate is preferably set by a user on the ventilator. Based on the target flow rate, a control unit generates a first control signal and adjusts the valve. In a further step, the measured values ​​of the first and at least one additional flow rate sensor are acquired and each assigned to a flow rate value of the valve module in the module's characteristic map. In a subsequent step, the actual flow rate is determined based on the assigned flow rate values ​​of the valve module. For example, the flow rate values ​​of the valve module are averaged. Preferably, the actual flow rate is determined taking into account weighting factors included in the module's characteristic map, whereby the actual flow rate results from the sum of the assigned flow rate values ​​of the valve module multiplied by the respective weighting factor.If the target volume flow and the actual volume flow differ, a second control signal is generated and the valve is adjusted again.

[0042] Further features, functions, and effects of the invention will become apparent from the following description of specific embodiments and the accompanying figures. Embodiments of the invention are described without limiting the general concept of the invention.

[0043] The figures show:

[0044] Fig. 1: a schematic representation of a valve module,

[0045] Fig. 2: a schematic representation of two volume flow curves of a module characteristic map for two volume flow sensors,

[0046] Fig. 3: a schematic representation of a second embodiment of a valve module, and

[0047] Fig. 4: a schematic representation of a ventilator with a valve module.

[0048] Exemplary embodiments of the invention are described in detail below with reference to the accompanying figures. Similar components are identified by the same reference numerals in several figures.

[0049] Fig. 1 shows a schematic representation of a first embodiment of a valve module 1 with an inlet 4 and an outlet 5, which can be connected to a ventilator 40 via fluid communication. The inlet 4 can be connected to a pressure source (not shown) or a blower 41 of a ventilator 40, so that a breathing gas can be introduced into the valve module. The inlet 4 is connected to the outlet 5 via a flow channel 3 via fluid communication. A valve 2 is arranged in the flow channel 3, which influences the breathing gas flow through the flow channel 3. Downstream of the valve 2, the flow channel 3 has a bend in which a first volume flow sensor 6 is arranged. Downstream of the bend in the flow channel 3, a second volume flow sensor 7 is arranged in the flow channel 3.Furthermore, Fig. 1 shows a valve actuator 8, which is operatively connected to a valve element of the valve 2 for the targeted modification of a valve gap of the valve 2, and a control unit 9 in the form of a microprocessor, which is electronically connected to the valve actuator 8 and the first and second volume flow sensors 8, 9. The control unit 9 controls the valve actuator 8 taking into account the measured values ​​of the first and second volume flow sensors 6, 7. The control unit 9 also includes a module characteristic map 10, which is stored in a data memory of the control unit 9.

[0050] Module characteristic map 10 was created prior to the intended use of valve module 1 and comprises measured values ​​from the first and second volume flow sensors 6, 7 as a function of the volume flow values ​​of the valve module. The volume flow values ​​of the valve module were recorded using an external measuring device, which included a volume flow sensor and was fluid-communicating with the outlet 5 of the valve module via an external flow channel, which served as a calming section for the breathing gas flow. During the creation process, breathing gas was introduced into the valve module through the inlet 4, and measured values ​​were recorded with the first and second volume flow sensors 6, 7 for various valve positions of the valve 2.

[0051] During operation of valve module 1, i.e., after its integration into a ventilator 40, valve module 1 influences the flow of breathing gas from outlet 5. Breathing gas is introduced into valve module 1 through inlet 4. The breathing gas then flows through valve 2 and further through flow channel 3 to outlet 5, with the volumetric flow rate of the breathing gas being measured by the first and second volumetric flow sensors 6 and 7, respectively.

[0052] To influence the respiratory gas flow, valve 2 can be adjusted according to a predefined target volume flow. The control unit 9 receives the target volume flow, which is specified, for example, by a user of the ventilator 40, and generates a control signal for the valve actuator 8, which adjusts the valve gap of valve 2 according to the control signal. The respiratory gas flow is controlled by the control unit 9 such that the actual volume flow of the valve module 1 corresponds at least approximately to the target volume flow. The actual volume flow is determined using the measured values ​​of the first and second volume flow sensors 6 and 7 and the module characteristic curve 10.

[0053] The actual volume flow rate is derived from at least one measured value each from the first and second volume flow sensors 6, 7. A volume flow value of the valve module 1 can be assigned to these measured values ​​in the module characteristic map 10, where the module characteristic map comprises measured values ​​of the first and second volume flow sensors 6, 7 acquired before the intended use of the valve module 1 and their corresponding volume flow values ​​of the valve module 1. If a direct assignment of a measured value from the first and / or second volume flow sensor to a measured value in the module characteristic map 10 or to a volume flow value of the valve module 1 is not possible, then the measured value in the module characteristic map 10 whose difference to the measured value of the first and / or second volume flow sensor 6, 7 is used. Thus, the measured values ​​of the first and second volume flow sensors 6, 7 can in any case be assigned to a volume flow value of the valve module.The mean of the determined volume flow values ​​forms the actual volume flow of the valve module and is taken into account by the control unit 9 when regulating the breathing gas flow.

[0054] According to the embodiment described here, the module characteristic map 10 additionally includes a weighting factor for the respective measured values ​​in the module characteristic map, which indicates the proportion to which a volume flow value of the valve module 1 corresponding to the measured value is to be taken into account. In this case, instead of calculating an average value as previously described, the determined volume flow values ​​of the valve module 1 proportionally yield the actual volume flow according to the respective weighting factor. This advantageously takes into account the fact that the volume flow sensors 6, 7 exhibit varying levels of measurement quality across the entire volume flow range compared to the actual volume flow of the valve module 1, as shown in Fig. 2.

[0055] Fig. 2 shows a schematic representation of two volume flow curves of a module characteristic map for two volume flow sensors in the valve module 1, 30. The measured values ​​m of the first volume flow sensor 6, as shown in Fig. 1 and Fig. 2, and the measured values ​​m of the second volume flow sensor 7, also as shown in Fig. 1 and Fig. 2, are shown as a function of the volume flow Q of the valve module. The measured values ​​m of the volume flow sensors 6, 7 and the volume flow Q of the valve module were recorded, as described above, before the intended use of the valve module and are encompassed by the module characteristic map 10.

[0056] The measured value profiles 21, 22 in Fig. 2 show the characteristics and dependencies of the volume flow rate on the properties of the valve module 1, 30, in particular on the properties of the valve 2, the arrangement of the volume flow sensors 6, 7, and the geometry of the flow channel 3. The measured value profile 21 of the first volume flow sensor 6 is higher than the measured value profile 22 of the second volume flow sensor 7 in the region up to Q1. In the region Q1 to Q2, the measured value profile 22 is higher than the measured value profile 21, and from Q2 onwards, the measured value profile 21 is again higher than the measured value profile 22. The reason for these non-linear measured value profiles 21, 22 is the non-harmonic flow components in the breathing gas flow, which occur particularly at small volume flows, and the volume flow sensors 6, 7 being arranged near the valve 2.These exemplary measurement curves 21, 22 are specific to the respective valve module 1, 30 and differ for valve modules of different designs. The aforementioned dependencies of the breathing gas flow to the valve 2, the geometry of the flow channel 3, and the arrangement of the volume flow sensors 6, 7 are depicted in the measurement curves 21, 22, making it possible to easily determine the actual volume flow of the valve module 1, 30 as described above and to simplify the control process.

[0057] Fig. 3 shows a schematic representation of a second embodiment of a valve module 30 according to the invention, which essentially corresponds to the representation in Fig. 1. Therefore, the description according to Fig. 1 applies accordingly. The differences between the second embodiment and the first embodiment of the valve module 30 are described below. In comparison to the first embodiment of the valve module 30, the second embodiment additionally includes the control unit 9 and the valve actuator 8. The control unit 9 and the valve actuator 8 are thus integrated into the valve module 30. This offers the advantage of particularly simple application of the valve module 30 and integration into a ventilator.

[0058] Furthermore, the valve module 30 includes a communication interface 32, which is electronically connected to the control unit 9. The purpose of the communication interface is to allow data, such as a target volume flow and the module characteristic curve 10, to be transmitted to the control unit 9. For example, data can thus be received from or transmitted to a ventilator 40.

[0059] The valve module 30 further comprises a pressure sensor 31, which is electronically connected to the control unit 9. The pressure sensor 31 is arranged such that it detects the pressure in the flow channel 3 between the inlet 4 and the valve 2. Thus, the pressure of a breathing gas introduced into the valve module 30 can be determined. The pressure influences the valve 2, whereby, for example, the valve gap is more open in the case of a high pressure than in the case of a low pressure, given the same control signal from the control unit 9. In this embodiment, the control signal for changing the valve gap of the valve 2 is additionally generated taking the measured pressure into account. Considering the pressure measured by the pressure sensor 31 improves the control and allows the breathing gas flow to be influenced particularly well, so that it corresponds at least almost exactly to the desired behavior.

[0060] Fig. 4 shows a schematic representation of a ventilator with a valve module 30 according to the second embodiment in Fig. 3. The ventilator is greatly simplified and, in addition to the valve module 30, includes a ventilator inlet 44 through which air from the environment of the ventilator 40 is drawn in by a blower 41, compressed, and directed to the inlet 4 of the valve module. Furthermore, the ventilator 40 includes a ventilator control unit 42 for controlling the blower 41 and the valve module 30. The ventilator control unit 42 controls the speed of the blower 41 and transmits a setpoint for the respiratory gas flow to the valve module, either wired or wirelessly. This setpoint is, in particular, a target volume flow rate, which can be adjusted via an operating unit (not shown) on the ventilator 40.The outlet 4 of the valve module 30 is fluid-communicating with a ventilator outlet 45, wherein a ventilator pressure sensor 43 is additionally arranged to measure the pressure of the breathing gas flow from the outlet 5 of the valve module 30. The ventilator outlet can be connected to a breathing gas hose (not shown).

[0061] After the ventilator 40 and the valve module 30 are put into operation, the ventilator control unit 42 sends a target volume flow rate to the valve module 30 and activates the blower 41, so that respiratory gas is directed through the inlet 4 into the valve module. As previously described, the control unit 9 of the valve module 30 controls the valve actuator 8 and the valve 2 according to the target volume flow rate. Subsequently, the actual volume flow rate is determined taking into account the first and at least one further volume flow sensor 6, 7 and the module characteristic curve 10, compared with the target volume flow rate, and if there is a deviation between the target and actual volume flow rates, another control signal is generated for the valve actuator 8. The respiratory gas flows from the outlet 5 of the valve module 30 to the

[0062] Ventilator outlet 45 and is available there for further use.

[0063] List of reference signs

[0064] 1 Valve module, first embodiment

[0065] 2 valve

[0066] 3 Flow channel

[0067] 4 Entrance

[0068] 5 outlets

[0069] 6 first volume flow sensor

[0070] 7 second volume flow sensor

[0071] 8 valve actuator

[0072] 9 Control unit

[0073] 10 Module characteristic map

[0074] 21 Measurement history of the first volume flow sensor

[0075] 22 Measurement history of the second volume flow sensor

[0076] 30 Valve module, second embodiment

[0077] 31 Pressure sensor

[0078] 32 Communication interface

[0079] 40 ventilators

[0080] 41 blowers

[0081] 42 Ventilator control unit

[0082] 43 Ventilator pressure sensor

[0083] 44 Ventilator inlet

[0084] 45 Ventilator outlet

Claims

Patent claims 1. Valve module (1, 30) for a ventilator (40) for influencing the flow characteristics of a respiratory gas flow, comprising a flow channel (3) in which a valve (2) is arranged, wherein the flow channel (3) has an inlet (4) and an outlet (5) which can be connected to the ventilator (40) via fluid communication, and comprising a first volume flow sensor (6) for measuring a volume flow in the flow channel (3), characterized in that at least one further volume flow sensor (7) is provided for measuring a volume flow in the flow channel (3) and the valve (2) can be controlled taking into account a setpoint, a measured value of the first volume flow sensor, a measured value of the at least one further volume flow sensor and a module characteristic map (10) generated before intended use.wherein the module characteristic map (10) includes measured values ​​acquired at least by the first volume flow sensor (6) and by at least one further volume flow sensor (7).

2. Valve module (1 , 30) according to claim 1 , characterized in that the valve (2) is designed as a low-pressure valve or as a high-lumen low-pressure valve.

3. Valve module (1 , 30) according to claim 1 or 2, characterized in that the first volume flow sensor (6) and the at least one further volume flow sensor (7) are arranged such that they at least temporarily detect different measured values, wherein the volume flow of the respiratory gas flow to be measured at a respective measuring point of the first volume flow sensor and the at least one further volume flow sensor is influenced by the geometry of the flow channel (3).

4. Valve module (1, 30) according to one of the preceding claims, characterized in that the first volume flow sensor (6) and the at least one additional volume flow sensor (7) is arranged in the immediate vicinity of the valve (2).

5. Valve module (1 , 30) according to one of the preceding claims, characterized in that the first volume flow sensor (6) and / or the at least one further volume flow sensor (7) is arranged on an inner wall in the flow channel (3).

6. Valve module (1 , 30) according to one of the preceding claims, characterized in that the first volume flow sensor (6) and / or the at least one further volume flow sensor (7) is arranged in a bypass of the flow channel (3).

7. Valve module (1 , 30) according to one of the preceding claims, characterized in that the flow channel (3) has at least a partial curvature and the first volume flow sensor (6) and / or the at least one further volume flow sensor (7) is arranged within a region of the curvature of the flow channel (3).

8. Valve module (1 , 30) according to one of the preceding claims, characterized in that a pressure sensor (31) is provided which is configured to detect a pressure measurement value in the flow channel (32) upstream of the valve and the valve (2) can be controlled taking into account the pressure measurement value.

9. Valve module (1 , 30) according to one of the preceding claims, characterized in that a control unit (9) is provided which is configured to generate a control signal for targeted adjustment of the valve (2) taking into account the setpoint, the measured value of the first volume flow sensor (6), the measured value of the at least one further volume flow sensor (7) and the module characteristic map (10).

10. Valve module (1 , 30) according to one of the preceding claims, characterized in that the first volume flow sensor (6) and / or the at least one further volume flow sensor (7) is designed as a heat flux sensor.

11. Valve module (1 , 30) according to claim 10, characterized in that the first volume flow sensor (6) designed as a heat flow sensor and / or the at least one further volume flow sensor (7) designed as a heat flow sensor comprises a heating wire, a microelectromechanical system, a heating resistor or a structured film.

12. Ventilator (40) with a valve module (1 , 30) according to one of the preceding claims.

13. Method for controlling a valve (2) of a ventilator (40) for influencing the flow characteristics of a respiratory gas flow with a valve module (1, 30) comprising a flow channel (3) with the valve (2) as well as a first volume flow sensor (6) and at least one further volume flow sensor (7) for measuring a volume flow of the respiratory gas flow, wherein a control signal for targeted adjustment of the valve (2) is generated taking into account a setpoint and a measured value of the first volume flow sensor (6), characterized in that the control signal is further generated taking into account a measured value of the at least one further volume flow sensor (7) and a module characteristic map (10), wherein the module characteristic map (10) is generated before the intended use of the valve module (1, 30) and comprises measured values ​​generated at least with the first volume flow sensor (6) and with the at least one further volume flow sensor (7).

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