DE102020108199A1 - Method and device for determining the volume flow, pressure and composition of a gas - Google Patents

Abstract

The invention relates to a method and a device (10) for determining the volume flow (V), pressure (p) and composition of a gas which is passed through a flow channel (12) when breathing / ventilating a patient (P). A flexible support membrane (16) is arranged in the flow channel (12) orthogonally to the flow direction (S) of the gas, with at least one first sensor (18), in particular in the form of a strain gauge, being attached to at least one surface (17) of the support membrane (16) . The support membrane (16) is deformable within the flow channel (12) depending on the volume flow (V) of the gas, with at least one signal depending on the volume flow (V) of the gas when the support membrane (16) moves and / or the first sensor is deformed is produced. A pressure of the gas is measured by means of a pressure measuring device (20) which is arranged in the flow channel (12), in particular in the area of its wall (W). The composition of the gas is determined by a second sensor (24) arranged within the flow channel (12).

Description

The invention relates to a method and a device for determining the volume flow, pressure and composition of a gas when breathing or ventilating a patient.

In the field of medicine, when supplying patients with breathing gas or breathing air, it is generally necessary that precise information about this breathing gas or about this breathing air is available. For this purpose, measurement parameters are recorded which are characteristic of a breathing gas or breathing air that is supplied to the patient or inhaled by the patient or exhaled by the patient. These measurement parameters include in particular the amount of breathing gas supplied, which is determined from the volume flow, the pressure of the supplied gas and its composition, especially with regard to the proportions of oxygen and carbon dioxide contained therein and their concentration.

According to the prior art, it is known that volume flow sensors are formed from a hot wire anemometer. In a known way, a very thin wire is used in hot wire anemometry, which has a diameter of only a few micrometers and usually consists of platinum, nickel, tungsten or various alloys thereof. The measuring principle is that this thin wire is heated electrically, whereby the heat given off by this wire to the air flowing past is used to determine the flow velocity.

the end DE 10 2010 030 324 A1 , DE 20 2017 005 964 U1 and DE 11 2013 001 902 T5 ventilation devices are known in which volume flow or flow rate sensors based on a hot wire anemometer are used.

Furthermore it is off DE 10 2017 124 256 A1 a breathing gas detection system is known in which the concentration of carbon dioxide in the breathing gas is determined using a thermal conductivity sensor, which can be designed in the form of a hot wire anemometer.

The provision of a hot wire anemometer, in particular for the formation of a volume flow sensor, is expensive per se and has the further disadvantage that in connection with this, complex and fast control loops are usually required in order to keep the hot wire at an average temperature.

According to the prior art, another measuring principle for determining a volume flow, which is less complex compared to hot wire anemometry, consists in that a sensor, in particular in the form of a strain gauge, is attached to a flexible support membrane, with a gas flowing against the support membrane and here projects into a flow channel through which the gas is conducted to a patient or is conducted away from the patient. The deformation that occurs for the flexible carrier membrane with the strain gauge attached to it when the gas flows into it is converted by the strain gauge into a signal which, as a rule, has a clear functional relationship to the volume flow of the gas within the flow channel. A volume flow measurement with the help of such strain gauges attached to a flexible carrier membrane is, for example, over GB 2121185 A , WO 2011/067734 A1 or off WO 2015/169848 A1 known. Nevertheless, it is not known from these publications that the devices shown here, which, as explained, are equipped with strain gauges for measuring the volume flow of a gas, also allow an analysis of a gas passed through a flow channel with regard to its individual components such as oxygen or carbon dioxide.

Accordingly, the invention is based on the object, in connection with breathing or ventilation of a patient in relation to a gas that flows to or from the patient, the determination of characteristic measurement parameters of this gas, which also include the analysis of the constituents of the gas, to optimize with particularly inexpensive and simple means.

The above object is achieved by a method having the features of claim 1 and by a device defined by the features of claim 15. Advantageous further developments of the invention are the subject of the dependent claims.

The present invention provides a method with which the volume flow (flow), pressure and composition of a gas which is passed through a flow channel when breathing or ventilating a patient can be determined. The volume flow of the gas is measured by means of a flexible carrier membrane which is arranged in the flow channel essentially orthogonally to the direction of flow of the gas, with at least one first sensor, in particular in the form of a strain gauge or a piezo element, being attached to at least one surface of the carrier membrane. The flexible support membrane can be deformed within the flow channel depending on the volume flow of the gas, with a movement of the support membrane and / or deformation of the first sensor, at least one signal is generated as a function of the volume flow of the gas. Furthermore, a pressure measuring device is arranged in the flow channel, in particular in the area of its wall, with this pressure measuring device being used to measure a static pressure for the gas flowing within the flow channel in comparison to the external environment of the flow channel. The composition of the gas, in particular selected gases formed from the group of at least oxygen (O ₂ ) and carbon dioxide (CO ₂ ), is determined by at least one, in particular catalytic, second sensor arranged within the flow channel.

In the same way, the invention provides a device with which the volume flow (flow), pressure and composition of a gas can be determined when breathing or ventilating a patient. Such a device comprises a flow channel, which can be connected to a ventilator and through which the gas can flow, at least one flexible support membrane which is arranged in the flow channel essentially orthogonally to the flow direction of the gas, at least one on at least one surface of the support membrane The first sensor, in particular in the form of a strain gauge or a piezo element, is attached, the carrier membrane being deformable within the flow channel depending on the volume flow of the gas and at least one signal depending on the volume flow of the gas being generated when the carrier membrane moves and / or the first sensor is deformed , a pressure measuring device which is arranged in the flow channel, in particular in the area of its wall, with this pressure measuring device measuring a static pressure for the gas flowing within the flow channel in comparison to the external environment of the flow channel r is, and at least one, in particular catalytic, second sensor arranged within the flow channel, with which a composition of the gas, in particular selected gases formed from the group of at least oxygen (O ₂ ) and carbon dioxide (CO ₂ ), can be determined.

In the present invention, the first sensor, which is attached to at least one surface of the flexible carrier membrane, can expediently be designed in the form of a strain gauge (“DMS” for short). As a rule, a movement or deflection of the flexible support membrane when the gas flowing through the flow channel flows against it leads to a deformation of the DMS, which then generates an electrical signal that is dependent on the volume flow passed through the flow channel, for example proportional to it.

In order to optimize a bidirectional measurement of the volume flow with the flexible support membrane, it is provided according to an advantageous development of the invention that first sensors are attached to both sides of the support membrane, i.e. on opposite surfaces thereof. Nevertheless, it should be pointed out at this point that a bidirectional measurement of the volume flow is already possible if a first sensor, for example in the form of a strain gauge, is provided only on or on one surface of the flexible carrier membrane, i.e. only on one side thereof.

A first sensor in the form of a strain gauge can either be attached from the outside to a surface of the flexible carrier membrane, for example by gluing. In addition or as an alternative to this, it is also possible to incorporate a DMS structurally into the material of the flexible support membrane.

As an alternative to a DMS, a first sensor can also be designed in the form of a piezo element. The piezo effect is used here. This means that when the flexible support membrane is moved or deformed, a mechanical force acts on a piezo element attached to or on the support membrane in the event of a gas flowing through the flow channel, which in turn produces an electrical voltage that results in a signal is converted, which is dependent on or proportional to the volume flow of the gas within the flow channel.

The measurement of the volume flow for a gas passed through the flow channel through at least one first sensor is, compared to the measurement technology based on hot wire anemometry, much simpler and more cost-effective insofar as this first sensor is preferably attached in the form of a strain gauge to the surface of a flexible support membrane and in the event of a deformation of the first sensor, which occurs when the gas flows against the carrier membrane and the resulting deflection of the carrier membrane, an electrical signal is generated which is dependent on or proportional to the volume flow of the gas.

As already explained, according to an advantageous development of the invention, it can be recommended that first sensors, for example in the form of a DMS or a piezo element, are attached to the opposite surfaces of the flexible carrier membrane. For a gas conducted in the flow channel, this enables a measurement of its volume flow in both directions.

The invention is based on the essential knowledge that it is herewith more robust and it is reliably possible to simultaneously measure or determine several measurement parameters for a gas that is either passed to the patient or has been exhaled by the patient and flows away from him. These parameters include the volume flow, which, as explained, is determined with the aid of a first sensor attached to a flexible support membrane and preferably with a strain gauge, and the pressure of the gas, in particular the components of the gas, for example the proportions of oxygen and / or carbon dioxide, which are contained in the gas passed through the flow channel and can be determined by means of the second sensor.

With the device according to the invention, a compact and inexpensive combination device is created, preferably in the form of a disposable article, with which the aforementioned measurement parameters for a gas flowing from or to the patient can be determined in a simple and robust manner.

In an advantageous development of the invention, it is provided that the said measurement parameters of the gas passed through the flow channel (ie volume flow (flow), pressure and composition of a gas) are determined for the portion of the gas that flows through the flow channel in the direction of the patient and is inhaled accordingly by the patient or actively flows into the patient's lungs. In this context, the gas that is directed towards the patient can be referred to as “fresh gas”.

In an advantageous further development of the invention, it is provided that the determination of the volume flow (flow), pressure and composition of a gas takes place for the portion of the gas which flows through the flow channel away from the patient and has accordingly been exhaled by the patient.

In this context, the gas that has been exhaled by the patient and flows away from him can be referred to as “patient gas”.

In an advantageous further development of the invention, an evaluation unit is provided for the method or the device. It is thus possible for the measured values of a first sensor attached to the flexible carrier membrane, the pressure measuring device and the second sensor to be transmitted to this evaluation unit. Such a transmission of the measured values to the evaluation unit can take place via a cable, whereby a falsification of these measured values by possibly other (interfering) signals is excluded.

For further processing or further use of the measured values that have been received by the evaluation unit from the first sensor, the pressure measuring device and the second sensor, it is advantageous if these measured values are digitized. For this purpose, the evaluation unit can be equipped with suitable means, which are set up in terms of programming in such a way that the measured values of the first sensor, the second sensor and the pressure measuring device can be digitized and preferably can also be stored in the evaluation unit.

In an advantageous development of the invention, a transmission unit is provided which is in signal connection with the evaluation unit, preferably also wired. Thus, the measured values of the first sensor, the second sensor and the pressure measuring device received by the evaluation unit can be transmitted to the transmission unit for the purpose of a subsequent transmission of these measured values by the transmission unit to a further external device.

It is advantageous if the evaluation unit and the transmission unit are designed to be integrated in a common device. On the one hand, this saves space and, on the other hand, enables short cable or data connections between the individual electronic components of these units.

The data transmission of the measured values of the first sensor, the second sensor and the pressure measuring device from the transmitting unit to an external device can take place wirelessly via a radio link or the like. For example, the Bluetooth communication protocol or the ZigBee communication protocol is suitable for this wireless data transmission.

In an advantageous development of the invention, the external device to which the measurement data are sent from the transmitting unit can be a regulating or control device for patient ventilation. In other words, such a regulating or control device can be part of a ventilator with which the method according to the invention is carried out and / or with which the device according to the invention is used together. On the basis of this, the measured values of the first sensor, the second sensor and the pressure measuring device can then be suitably processed by the regulating or control device of the ventilator and taken into account for the control or regulation of the ventilation of a patient.

In an advantageous development of the method according to the invention, the volume flow (flow), the pressure and the composition of the Gas, which is passed into a flow channel leading to the patient, can be controlled, preferably regulated, by means of a regulating or control device of a ventilator depending on the measured values of the first sensor attached to the flexible carrier membrane, the pressure measuring device and the, in particular, catalytic second sensor. This ensures that support or control / regulation of the patient's breathing by means of the ventilator actually only takes place with the parameters required for this purpose, which correspond to predetermined values.

In an advantageous development of the invention, a display unit (display) can be provided which is in signal connection with the regulating or control device. With the help of this display unit, both the measured values of the first sensor, the second sensor and the pressure measuring device, which have been transmitted by the transmitting unit, as well as the control variables of the regulating or control device, with which the ventilation of a patient is supported or controlled / regulated , be appropriately visualized.

When using or carrying out the present invention, the volume flow for a gas guided through the flow channel is determined, as explained, by a first sensor which determines at least one surface of a flexible support membrane arranged essentially orthogonally to the direction of flow. The aim here is for the gas to flow against the flexible carrier membrane uniformly and free of turbulence. For this purpose, according to an advantageous further development of the invention, it is provided that the flow of the gas within the flow channel is laminarized or evened out adjacent to or in the vicinity of the carrier membrane. A laminarization device used for this purpose can be arranged upstream and / or downstream of the carrier membrane, as seen in the direction of the patient. This means that such a laminarization device is arranged either only on one side of the carrier membrane, for example upstream of the carrier membrane when viewed in the direction of the patient (namely for the “fresh gas” explained above), or that such laminarization devices are arranged on both sides of the carrier membrane. In the latter case, it is ensured that the patient gas, which flows from the direction of the patient to the carrier membrane, is specifically laminarized before it reaches the carrier membrane.

To protect the patient from the fact that the "fresh gas" supplied to him contains impurities and / or germs or bacteria, an advantageous development of the invention can provide that a particle is used for the fresh gas introduced or flowing into the flow channel - and / or bacterial filter is provided. This filter ensures that the “fresh gas” flowing in the direction of the patient is effectively filtered with regard to particles and / or bacteria or germs.

In the same way, according to an advantageous development of the invention, it can be provided that a particle and / or bacterial filter for the patient gas is arranged in the flow channel. This ensures that the patient gas, which has been exhaled by the patient and flows away from him, is effectively filtered with regard to impurities and / or germs or bacteria, so that these are not transported further in the flow channel and possibly up to a ventilator connected to the flow channel.

At this point, with regard to the above-mentioned particle and / or bacteria filter, it is pointed out separately that it can effectively filter out any interfering particles from the gas, and thus also virus particles (also called “virions”). This means that with the help of a particle and / or bacterial filter, viruses or “virions” can also be filtered out of the gas, namely both the “fresh gas” flowing in the direction of the patient and the patient gas exhaled by the patient. This ensures that viruses are neither ingested by the patient nor released into the environment or to the ventilator.

In an advantageous development of the invention, it is possible for the volume flow that has been passed and determined through the flow channel to be converted into a total volume of the gas. This is possible both for the “fresh gas” that is directed towards the patient and for the “patient gas” that has been exhaled by the patient.

Based on the fact that, as explained above, a total volume of the gas conducted through the flow channel is determined, it is also possible to determine a remaining service life for a particle and / or bacterial filter used in connection with the invention. After this idle time has been reached, either this filter or the entire device according to the invention including this filter can be replaced in good time in order to avoid contamination of the patient and / or the ventilator.

In an advantageous development of the invention it can be provided that a laminarization device and a particle and / or bacterial filter are combined into an integrated unit. This leads to the advantage of a small space requirement within the flow channel at the point where both a laminarization of the gas flow and a filtering is desired. Such an integrated unit consisting of a laminarization device and a particle and / or bacterial filter can be arranged in a targeted manner either on only one side of the carrier membrane or on both sides of the carrier membrane.

In an advantageous development of the method according to the invention, it can be provided that the volume flow (flow) conducted through the flow channel is converted into at least one volume value on the basis of a derived variable. This volume value can be a tidal volume (V _T ) and / or a minute volume (V _M ).

According to an advantageous development, the device according to the invention comprises a battery or accumulator unit which is electrically connected to the electrical or electronic components of the device for supplying energy. The capacity of this battery or accumulator unit is expediently selected to be so large that an energy supply for the electrical or electronic components of the device connected to the battery or accumulator unit for a duration of at least 24 hours, preferably of at least 36 hours, more preferably of at least 48 hours is guaranteed.

If the device according to the invention is designed as a disposable article, it can be provided that the battery or accumulator unit can be removed from a housing of the device. This follows the approach that in the course of disposing of the device, the battery or accumulator unit is either disposed of separately from the device for environmental reasons, or that - in the case of a pure accumulator unit - this is possibly again for a new device after a suitable charging process Use comes.

• 1 eine erfindungsgemäße Vorrichtung in einer prinzipiellen Schnittansicht gemäß einer ersten Ausführungsform,
• 2 eine erfindungsgemäße Vorrichtung in einer prinzipiellen Schnittansicht gemäß einer zweiten Ausführungsform,
• 3 eine Längsschnittansicht durch einen Strömungskanal der Vorrichtung von 1,
• 4 eine Längsschnittansicht durch einen Strömungskanal der Vorrichtung von 2,
• 5 eine Frontalansicht auf eine flexible Trägermembran gemäß der Ausführungsform von 1,
• 6 eine Frontalansicht auf eine flexible Trägermembran gemäß der Ausführungsform von 2,
• 7 eine erfindungsgemäße Vorrichtung in einer prinzipiellen Schnittansicht gemäß einer dritten Ausführungsform,
• 8 eine erfindungsgemäße Vorrichtung in einer prinzipiellen Schnittansicht gemäß einer vierten Ausführungsform,
• 9 eine prinzipiell vereinfachte Seitenansicht einer flexiblen Trägermembran der erfindungsgemäßen Vorrichtung, und
• 10 eine prinzipiell vereinfachte Seitenansicht einer flexiblen Trägermembran der erfindungsgemäßen Vorrichtung nach einer weiteren Ausführungsform.

Preferred embodiments of the invention are described in detail below with reference to a schematically simplified drawing. Show it:

• 1 a device according to the invention in a basic sectional view according to a first embodiment,
• 2 a device according to the invention in a basic sectional view according to a second embodiment,
• 3 a longitudinal sectional view through a flow channel of the device of 1 ,
• 4th a longitudinal sectional view through a flow channel of the device of 2 ,
• 5 a front view of a flexible carrier membrane according to the embodiment of FIG 1 ,
• 6th a front view of a flexible carrier membrane according to the embodiment of FIG 2 ,
• 7th a device according to the invention in a basic sectional view according to a third embodiment,
• 8th a device according to the invention in a basic sectional view according to a fourth embodiment,
• 9 a basically simplified side view of a flexible support membrane of the device according to the invention, and
• 10 a basically simplified side view of a flexible support membrane of the device according to the invention according to a further embodiment.

With reference to the 1-10 are preferred embodiments of a device according to the invention below 10 and a corresponding method with which a patient breathes or is ventilated through a flow channel. The same features in the drawing are each provided with the same reference symbols. At this point, it is pointed out separately that the drawing is only shown in a simplified manner and, in particular, without a scale.

In a first embodiment according to 1 comprises the device according to the invention 10 a flow channel 12th from a ventilator 14th to a patient P. leads.

Inside the flow channel 12th is on its inner peripheral surface 13th a flexible support membrane 16 appropriate. The two arrows in 1 at the lower end of the support membrane 16 are shown, it is symbolized that at this point the support membrane 16 not with the inner peripheral surface 13th of the flow channel 12th is connected and in this respect with its free end thereby formed within the flow channel 12th is movable back and forth.

On the two opposite surfaces 17th the support membrane 16 are the first sensors 18th in the form of strain gauges ("DMS" for short) attached. In the 1 these strain gauges are each symbolized in a simplified manner only by dashed lines.

5 shows a front view of a flexible carrier membrane 16 according to the embodiment of 1 , namely from the direction of a flow direction S. . From this it can be seen that on a surface 17th the support membrane 16 several DMS are arranged, which are each symbolized here in a simplified representation by dotted lines.

Furthermore, from the representation of 5 can be seen that a lower free end of the support membrane 12th no contact with the adjacent inner peripheral surface 13th of the flow channel 12th Has. This provides the above-mentioned mobility of the lower free end of the flexible support membrane 16 guaranteed if the support membrane 12th from that through the flow channel 12th directed gas is flowed against it.

The support membrane 16 is also in the 9 shown in a principally simplified side view. It can be seen from this that a cross section of the support membrane 16 is essentially constant, with first sensors or DMS 18th on the two opposite surfaces of the support membrane 16 are appropriate, here symbolized in a greatly simplified manner by dashed lines.

For ventilation of the patient P. becomes a gas through the flow channel 12th passed through. With the arrows "S" are in the representation of 1 symbolizes the two possible directions of flow - this shows that a gas is flowing through the flow channel 12th both towards the patient P. (in 1 from left to right) and, after the patient exhales, away from the patient P. (in 1 from right to left) can flow.

The attachment of the support membrane 16 on the inner peripheral surface 13th the flow channel 12th is such that the support membrane 16 in the flow channel 12th essentially orthogonal to the direction of flow S. of the gas is arranged. This has the advantage that the carrier membrane 16 for bidirectional measurement of the volume flow V can be used, which is explained separately below.

The flexible carrier membrane 16 with the attached strain gauges 18th serves to control the volume flow V of the gas within the flow channel 12th to determine. The representation of 1 , to the right of the support membrane 16 , the symbol V symbolized in a circle. Details on this are explained separately below.

The flow channel 12th the device 10 can be connected to a Y-connector (not shown) which leads to the patient P. leads. Taking this Y-connector into account, you can use the one on the flexible support membrane 16 attached first sensor 18th (or the two DMS 18th ) both the inspiratory flow of a "fresh gas" flowing through the flow channel 12th directed in the direction of the patient and then inhaled by the patient, as well as the expiratory flow of a patient gas which has been exhaled by the patient can be determined. The same is true of the support membrane 16 and the strain gauges applied to it 18th a bidirectional measurement of the volume flow V possible, namely for the "fresh gas" FG which in the direction of the patient P. flows as well as for the patient gas PG which has been exhaled by the patient and is flowing away from him.

The device 10 comprises a pressure measuring device 20th with which a static pressure p for the gas is determined or measured, which is inside the flow channel 12th flows.

The pressure measuring device 20th can be in or on a wall W. of the flow channel 12th be arranged.

The measurement of static pressure p within the flow channel 12th can be done in that the pressure measuring device 20th is equipped with a strain gauge ("DMS") 21. In this case, the static pressure p within the flow channel 12th compared to that outside of the flow channel 12th prevailing ambient pressure based on the deformation of the strain gauge 21 certainly.

In addition or as an alternative to this, the pressure measuring device 20th also with a piezo element 22nd be equipped. In this case, the static pressure is then measured p that is inside the flow channel 12th prevails, in a known manner, taking into account a mechanical force, in particular from the direction of the flow channel 12th on the piezo element 22nd acts.

The symbolically simplified representation of 1 makes it clear that when attaching the pressure measuring device 20th on the flow channel 12th the DMS 21 or the piezo element 22nd in part of the wall W. of the flow channel 12th or can run in alignment with this.

The device 10 further comprises a second sensor 24 , with which a composition of the gas passed through the flow channel can be determined. With such an analysis of the gas, in particular the proportions of oxygen O ₂ and / or carbon dioxide CO ₂ or possibly other gases that may be contained in the gas can be determined.

The second sensor 24 can be designed in the form of a catalytic film, which as such is part of the state of the art and therefore does not require any further explanation at this point.

In addition or as an alternative, the second sensor 24 are based on the ultrasonic measuring principle. Correspondingly, the composition and the concentration of individual gas components are determined within the gas flow with an ultrasonic sensor.

Regardless of its measuring principle, the second sensor fulfills 24 when used with the device according to the invention 10 the function of a gas analyzer, with which, as explained, various gas proportions and their concentrations, which are contained in the gas passed through the flow channel, can be measured.

In the 1 The arrangement or positioning of the second sensor shown 24 within the flow channel 12th is only to be understood as an example. As an alternative to this, it can also be provided that the second sensor 24 in one parallel to the flow channel 12th extending secondary channel (not shown) is arranged, which branches off from the flow channel or opens into it. A measurement of the gas components and their concentration with a second sensor arranged in this alternative secondary channel 24 is possible with the same reliability as the in 1 arrangement shown in relation to the second sensor 24 .

Regarding the second sensor 24 it should also be noted that the device 10 also several such sensors 24 may have, for example, at different points along the flow channel 12th are provided. This plurality of second sensors 24 can either be based on the same measuring principle or work according to different measuring principles, for example like a catalytic film or according to the ultrasonic measuring principle as explained above.

The device comprises an evaluation unit 26th , which is intended to take the measured values of the first sensor 18th , the pressure measuring device 20th and the second sensor 24 to recieve. For this purpose, the evaluation unit 26th wired to the first sensor 18th , the pressure measuring device 20th and the second sensor 24 are in signal connection. In other words, leads from the first sensor 18th , the pressure measuring device 20th and the second sensor 24 one signal cable each to the evaluation unit 26th in order to send the individual measured values to the evaluation unit 26th transferred to.

The evaluation unit 26th may have a memory (not shown). Accordingly, the measured values of the first sensor can be 18th , the pressure measuring device 20th and the second sensor 24 in the memory of the evaluation unit 26th saved or filed.

For further processing of the measured values from the first sensor 18th , the pressure measuring device 20th and the second sensor 24 it is advantageous if these measured values are available in digitized form. The evaluation unit can accordingly 26th be set up in a program such that the measured values from the first sensor 18th , the pressure measuring device 20th and the second sensor 24 have been received, are suitably digitized following this reception. In this regard, it goes without saying that these digitized measured values are then also stored in the memory of the evaluation unit 26th can be saved.

The device 10 also includes a transmitter unit 28 in the same way as the evaluation unit 26th can be attached at any point on the device. This transmitter unit 28 stands with the evaluation unit 26th in signal connection, preferably wired. As an alternative to this, it is also possible that the transmission unit 28 directly with the first sensor 18th , the pressure measuring device 20th and the second sensor 24 is in signal connection, also preferably wired. In any case, the sending unit is 28 provided and designed for this purpose, the measured values of the first sensor 18th , the pressure measuring device 20th and the second sensor 24 or from the evaluation unit 26th received corresponding data to an external device, preferably wirelessly via a radio link F. or the like to send. The external device can be a regulating or control device of a ventilator, which is explained separately below.

The transmitter unit 28 and the evaluation unit 26th can expediently be designed to be integrated in a common device. Thus, these two units then form a common component for the device according to the invention, with which both the measured values of the first sensor can be received 18th , the pressure measuring device 20th and the second sensor 24 , if necessary a digitization of these measured values, and a subsequent sending or transmission of these measured values to an external further device is possible.

The device 10 is with a battery or accumulator unit 29 equipped to which the individual electrical or electronic components of the device 10 are connected. Accordingly, these components, namely the first sensor (or DMS) 18, the Pressure measuring device 20th , the second sensor 24 , the evaluation unit 26th and the transmitter unit 28 from the battery or accumulator unit 34 suitably supplied with energy.

The flow channel 12th the device 10 can with a ventilator 14th connected or connected to it.

The ventilator 14th has a regulating or control device 15th on. With the help of this regulating or control device 15th can be a breathing gas, which the patient through the flow channel 12th the device 10 is supplied in relation to the parameters volume flow V , Pressure and / or composition of the gas can be set to predetermined values, preferably in the manner of a control or regulation.

The ventilator 14th comprises a battery or accumulator unit 34 . With the help of this battery or accumulator unit 34 can the ventilator 14th can also be operated without mains voltage if necessary, for example if the mains voltage should fail. In this respect, thanks to the battery or accumulator unit 34 an "emergency mode" for the ventilator 14th ensured for at least a few hours or even days.

In the case of the external device to which the measured values from the first sensor 18th , the pressure measuring device 20th and the second sensor 24 from the transmitter unit 28 the device 10 are preferably transmitted via a radio link, it can be the regulating or control device 15th the ventilator 14th Act. In the representation of 1 this radio link is designated with "F" and symbolized by individual radio waves. As already explained in another place above, this radio link F. based on the Bluetooth communication protocol or on the ZigBee communication protocol.

The ventilator 14th is with a display unit D. equipped. On the display of this display unit D. can read the individual measured values of the device 10 that over the radio link F. from the regulating or control device 15th have been received, and / or the respective parameters that are relevant for that in the flow channel 12th introduced gas can be selected, visualized.

• Von dem Beatmungsgerät 14 wird ein inspiratorisches Gas, nachfolgend auch als „frisches Gas“ FG bezeichnet, mit einem vorbestimmten Volumenstrom V, einem vorbestimmten Druck p und einer vorbestimmten Gas-Zusammensetzung in den Strömungskanal 12 eingebracht und in Richtung des Patienten P geleitet.

The invention and the associated method now work as follows:

• From the ventilator 14th is an inspiratory gas, hereinafter also referred to as "fresh gas" FG referred to, with a predetermined volume flow V , a predetermined pressure p and a predetermined gas composition into the flow channel 12th introduced and in the direction of the patient P. directed.

When the flow hits the flexible support membrane 16 through the fresh gas FG there is a deflection of the support membrane 12th , which in the longitudinal sectional view of 3 is directed to the right and symbolized by the double-dot-dash line 16 '. As a result of this deflection, the strain gauges are deformed 18th that are on the surfaces 17th the support membrane 16 are appropriate. The electrical resistance of the strain gage changes accordingly 18th , the corresponding electrical signals to the evaluation unit 26th be sent. The size of these electrical signals or the amount of change in the electrical resistance of the strain gauges 18th depends on the deflection of the flexible support membrane 16 , for example proportional to this, and thus represents a parameter for the volume flow V with which the fresh gas FG through the flow channel 12th is conducted and, as explained, the flexible support membrane 16 flows towards.

By means of the flexible carrier membrane 16 can also be the volume flow V of the patient gas PG measured by the patient P. has been exhaled. When the flow hits the flexible support membrane 16 through the patient gas PG becomes the support membrane 16 now deflected in the opposite direction, which is shown in the longitudinal sectional view of 3 directed to the left and symbolized by the double-dot-dash line 16 ″. In the same way as before with the deflection by the fresh gas FG is now when through the patient gas PG caused 16 "deflection of the support membrane 16 to the left the electrical resistance of the two strain gauges 18th that are on the surfaces 17th the support membrane 16 are appropriate, changed. As a result, the DMS 18th electrical signals are generated and sent to the evaluation unit 26th sent. These electrical signals represent a parameter for the volume flow V represent, with which now the flow channel 12th from the patient gas PG is flowed through.

The optional measurement of the volume flow V either for the fresh gas FG or for the patient gas is shown in 1 also symbolized by a double arrow in the central area of the support membrane 16 runs horizontally.

For the functioning of the device according to the invention 10 and the corresponding method is important that simultaneously to the measurement of the volume flow V as explained above for either the fresh gas FG or for the patient gas PG is carried out with the help of the pressure measuring device 20th also the static pressure p determined for that through the flow channel 12th piped gas (i.e. the fresh gas FG or the patient gas PG ) within the flow channel 12th is present. At the same time, the second sensor 24 determines the individual proportions of the respective gas and their concentration (s).

In the same way as for the DMS 18th then the measured values of both the pressure measuring device 20th as well as the second sensor 24 to the evaluation unit 26th sent.

After receiving the stated measured values by the evaluation unit 26th , and possibly following an optional digitization, which as explained by means of the evaluation unit 26th is possible, these measured values are sent to the transmitter unit 28 and then from the transmitter unit 28 over the radio link F. to the regulating or control device 15th the ventilator 14th transfer.

While the ventilator is in operation 14th can use the received measured values of the device 10 , ie the current information determined in relation to the volume flow V , Pressure p and composition of the flow channel 12th piped gas (either the fresh gas FG or the patient gas PG ), from the regulating or control device 15th the ventilator 14th taken into account or processed, for example in a controlled system. On the basis of this it is then possible to use the fresh gas FG , which through the flow channel 12th towards the patient P. is directed to adjust appropriately.

Further embodiments of the invention are explained below. As far as these embodiments, the same functional principle as in the embodiment of 1 is based on the explanations to avoid repetition 1 to get expelled.

2 shows a second embodiment of the device according to the invention 10 . In contrast to the embodiment of 1 is here the support membrane 16 trained like a "sail". The support membrane extends here 16 essentially orthogonal to the direction of flow S. of the gas completely through a diameter of the flow channel 12th regardless of its cross-sectional geometry. This means that the support membrane 16 with their opposite realms B. , ie both with an upper edge area and with a lower edge area, in each case on the inner circumferential surface 13th of the flow channel 12th is attached. This type of attachment of the support membrane 16 is also in the longitudinal sectional view of FIG 4th as well as in the front view of the carrier membrane 16 according to the representation of 6th shown.

The frontal view of 6th also illustrates a possible course of individual DMS 18th standing on a surface 17th the support membrane 16 are attached or provided.

With regard to the second embodiment of the device 10 is a deflection of the support membrane 16 which, in the event of a flow through the in the flow channel 12th piped gas adjusts in the 4th shown in principle in a simplified manner.

With a flow through the inspiratory fresh gas FG becomes the support membrane 16 especially deflected to the right in its central area, as shown in 4th is symbolized by the double-dot-dash line 16 '. This leads to a deformation of the strain gage 18th . As a result, then in the same way as in the embodiment of 1 due to a change in the electrical resistance of the strain gage 18th , then electrical signals from the strain gauges 18th to the evaluation unit 26th sent, these electrical signals being a parameter for the volume flow V represent with which the fresh gas FG through the flow channel 12th is directed.

When flowing through the expiratory patient gas PG it comes for the support membrane 16 in the second embodiment - with reference to the longitudinal sectional view of FIG 4th - to a flow from right to left. Correspondingly, it occurs in particular in the central area of the flexible support membrane 16 to a left deflection, as shown in FIG 4th is symbolized by the double-dot-dash line 16 ″. The deformation of the strain gauges that occurs here 18th leads, as already explained, to a change in their electrical resistances, as a result of which then corresponding electrical signals to the evaluation unit 26th be sent.

The second embodiment of the device 10 according to 2 has in terms of attaching the support membrane 16 with their opposite realms B. on the inner peripheral surface 13th of the flow channel 12th compared to the embodiment of 1 the advantage that any spatial positioning of the device 10 less or no influence on the response behavior of the flexible support membrane 16 and its deflection increases when this support membrane 16 a gas flows from the side.

Otherwise, the mode of operation corresponds to the second embodiment of the device 10 according to 2 that of 1 .

7th shows a third embodiment of the device according to the invention 10 . Here are in addition to the second embodiment within the flow channel 12th Laminarization devices 30th arranged, namely on both sides of the support membrane 16 and in each case adjacent to it. These laminarization devices 30th are in 7th each symbolized in a greatly simplified manner by vertical dash-dotted lines.

If fresh gas FG or patient gas PG through the flow channel 12th towards the support membrane 16 are passed, this gas flows through the laminarization devices 30th through. As a result, the gas before it reaches the support membrane 16 achieved, evened out and freed from possible turbulence.

Noting that the flow of gas with which the support membrane 16 is flowed against, by means of the laminarization devices 30th has been evened out or laminarized, a better, i.e. more uniform, flow for the carrier membrane is achieved 16 achieved, which in turn leads to an optimized deflection of the support membrane 16 due to the gas flow. As a result, a more precise measurement of the volume flow can be achieved V by means of the support membrane 16 and the strain gauges attached to it 18th can be achieved because, for example, a "flutter" of the carrier membrane 16 is prevented by turbulence.

Otherwise, the mode of operation corresponds to the third embodiment of the device 10 according to 7th that of 1 .

8th shows a fourth embodiment of the device according to the invention 10 . Here are in addition to the third embodiment within the flow channel 12th adjacent to the laminarization facilities 30th each particle and / or bacterial filter 32 arranged, which are each shown symbolically simplified by hatched areas.

Through this particle and / or bacteria filter 32 any disturbing particles, dirt, bacteria, germs or the like that are in the fresh gas FG and / or in the patient gas PG can be contained, effectively withheld. As a result, these particles, dirt, bacteria, germs or the like cannot reach the patient P. nor to the ventilator 14th or reach the environment. In this context it is pointed out again that the particle and / or bacteria filter 32 Viruses or associated virus particles ("virions") are also suitable for this purpose from the fresh gas FG and / or from the patient gas PG to filter out.

With regard to the particulate and / or bacterial filters 32 it is useful if this is done with the laminarization devices 30th are designed as an integrated unit. In this case, the fresh gas FG or the patient gas PG when it flows through such an integrated unit, it is both laminarized with respect to its flow and suitably filtered.

Regarding the particle and / or bacteria filter 32 it is emphasized separately at this point that, contrary to the representation in 8th for the device according to the invention 10 possibly also without the laminarization devices 30th can be provided. It is also possible to use a particle and / or bacteria filter 32 possibly also only on one side of the support membrane 16 to arrange.

The representation of 8th also shows a housing 36 that is for the device 10 is provided and is symbolized here only in a simplified manner by a dot-dash rectangle. Regarding this housing 36 it goes without saying that all essential components of the device 10 in this case 36 housed or integrated therein. In this respect, the housing fulfills 36 for the components of the device received therein 10 also a protective function. It goes without saying that in 8th shown housing 36 in the same way also for the embodiments according to FIG 1 , 2 and 7th can be provided.

Otherwise, the mode of operation corresponds to the fourth embodiment of the device 10 according to 8th that of 1 .

In addition, with regard to the third and fourth embodiment of the device 10 it should be noted that, contrary to the representations in 7th respectively. 8th , an attachment of the support membrane 16 on the inner peripheral surface 13th of the flow channel 12th is also possible in the manner as it is in the first embodiment of 1 has been shown and explained.

10 shows a further variant for a possible configuration of the support membrane 16 which resemble the first embodiment of 1 only with its upper end on the inner circumferential surface 13th of the flow channel 12th is attached and thus has a lower free end. In the same way as with the 1 is in the 10 by the two arrows adjacent to the lower end of the support membrane 16 shows that a deflection of the support membrane 16 to the right or to the left is possible when by the fresh gas FG (from the left) or through the patient gas PG (from the right) is flown against. The side view of 10 shows that this variant of the carrier membrane 16 is trapezoidal in cross section along its longitudinal extension, the cross section decreasing in the direction of the lower free end. On the two opposite surfaces of the support membrane 16 are the first sensors 18th preferably attached in the form of strain gauges, for example according to an arrangement of 5 .

The variant of a carrier membrane 16 according to the embodiment of 10 has compared to the embodiment of 1 a greater bending stiffness in the direction of a flow direction S. , and is therefore suitable for relatively large volume flows V of a gas flowing through the flow channel 12th is passed through. In this regard, it should be pointed out that the embodiments of the device shown above 10 according to 1 , 7th and 8th alternatively with a support membrane according to the embodiment of FIG 10 can be equipped.

In all of the aforementioned embodiments of the device 10 it is possible that on the surfaces of the support membrane 16 and the first sensors attached to it 18th additional coatings are applied which have hygroscopic, hydrophilic, hydrophobic and / or protein-repellent properties. Such coatings can be on the surface or surfaces of the support membrane 16 be provided over the entire surface or locally. If such a coating has hygroscopic properties, this has the advantage, among other things, that viruses and / or bacteria can then also be bound in the water droplets that are deposited on or on this coating.

Finally, for all of the embodiments of the device according to the invention shown and explained above 10 it should be noted that the support membrane 16 their width does not extend over the entire cross-section of the flow channel 12th extends, but only in a partial area of the cross section of the flow channel 12th is arranged, for example in the form of a rectangular strip. As a result, it is for one inside the flow channel 12th conducted gas is always possible on the support membrane 16 to flow past laterally, as shown, for example, in the frontal views 5 and 6th can be seen. This means that a flexible support membrane 16 across the width of the flow channel 12th seen is only as large as it is for a sufficient flow and the desired deflection of the support membrane 16 is required to thereby by means of the first sensors 18th To receive measurement signals that are a key figure for the volume flow V of the gas.

List of reference symbols

10

contraption

12th

Flow channel

13th

Inner peripheral surface (of the flow channel 12th )

14th

Ventilator

15th

Regulation or control device

16

flexible support membrane

17th

Surface (of the support membrane 16 )

18th

first sensor (e.g. in the form of a strain gauge or a piezo element)

20th

Pressure measuring device

21

Strain gauges

22nd

Piezo element

24

second sensor (especially in the form of a catalytic film)

26th

Evaluation unit

28

Sending unit

29

Battery or accumulator unit (of the device 10 )

30th

Laminarization device

32

Particle and / or bacteria filter

34

Battery or accumulator unit (of the ventilator 14th )

36

Housing (for the individual components of the device 10 )

B.

opposite areas of the support membrane 16

D.

Display unit

F.

Radio link

p

Pressure (of a gas within the flow channel 12th )

P.

patient

FG

fresh gas

PG

Patient gas

S.

Direction of flow

V

Volume value

V

Volume flow

W.

Wall (of the flow channel 12th )

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102010030324 A1 [0004]
• DE 202017005964 U1 [0004]
• DE 112013001902 T5 [0004]
• DE 102017124256 A1 [0005]
• GB 2121185 A [0007]
• WO 2011/067734 A1 [0007]
• WO 2015/169848 A1 [0007]

Claims (27)

Method for determining the volume flow (V), pressure (p) and composition of a gas that is passed through a flow channel (12) when breathing or ventilating a patient (P), the volume flow (V) of the gas flowing through the flow channel (12 ) directed gas is determined by means of a flexible carrier membrane (16) which is arranged in the flow channel (12) essentially orthogonally to the flow direction (S) of the gas, with at least one first sensor on at least one surface (17) of the carrier membrane (16) (18) is attached in particular in the form of a strain gauge or a piezo element, the carrier membrane (16) being deformable within the flow channel (12) as a function of the volume flow (V) of the gas, with a movement of the carrier membrane (16) and / or Deformation of the first sensor generates at least one signal as a function of the volume flow (V) of the gas, with a pressure measuring device (20) in the flow channel (12) in particular in the area is arranged by the wall (W), with this pressure measuring device (20) a static pressure (p) for the gas flowing within the flow channel (12) is measured in comparison to the external environment of the flow channel (12), and the composition of the Gas, in particular selected gases formed from the group of at least oxygen (O ₂ ) and carbon dioxide (CO ₂ ), is determined by at least one, in particular catalytic, second sensor (24) arranged within the flow channel (12). Procedure according to Claim 1 , characterized in that the determination of the volume flow (V), pressure (p) and composition of a gas for a fresh gas (FG) which flows through the flow channel (12) in the direction of the patient (P) and accordingly from the patient (P ) is inhaled or actively flowing into the patient's (P) lungs. Procedure according to Claim 1 or 2 , characterized in that the determination of the volume flow (V), pressure (p) and composition of a gas for a patient gas (PG) takes place, which flows through the flow channel (12) away from the patient (P) and accordingly from the patient (P) has been exhaled. Method according to one of the Claims 1 until 3 , characterized in that the measured values of a first sensor (18) attached to the flexible support membrane (16), the pressure measuring device (20) and the, in particular, catalytic second sensor (24) are transmitted to an evaluation unit (26), preferably by cable. Procedure according to Claim 4 , characterized in that the measured values received by the evaluation unit (26) are digitized. Procedure according to Claim 4 or 5 , characterized in that the measured values are transmitted from the evaluation unit (26) to a transmission unit (28), preferably that the transmission unit (28) and the evaluation unit (26) are designed to be integrated in a common device. Procedure according to Claim 6 , characterized in that the measured values are transmitted from the transmitting unit (28) to a regulating or control device (15) for patient ventilation, preferably in that the regulating or control device (15) comprises a display unit (D), more preferably that the regulating or control device (15) is part of a ventilator (14). Procedure according to Claim 7 , characterized in that the transmission of the measured values from the transmitting unit (28) to the regulating or control device (15) for patient ventilation takes place wirelessly and in particular via the Bluetooth communication protocol or the ZigBee communication protocol. Method according to one of the preceding claims, characterized in that the flow of the gas within the flow channel (12) is laminarized adjacent to or in the vicinity of the carrier membrane (16). Method according to one of the preceding claims, characterized in that a particle and / or bacterial filter (32) is provided for fresh gas (FG) flowing into the flow channel (12), with which the gas flowing in the direction of the patient (P) in Is filtered with respect to particles and / or bacteria or germs. Method according to one of the preceding claims, characterized in that the volume flow (V), the pressure (p) and the composition of the gas which is passed into a section of the flow channel (12) leading to the patient (P), by means of a control or the control device (15) can be controlled, preferably regulated, as a function of the measured values of a first sensor (18) attached to the flexible support membrane (16), the pressure measuring device (20) and the, in particular, catalytic second sensor (24). Method according to one of the preceding claims, characterized in that a particle and / or bacteria filter (32) is provided for the patient gas (PG) flowing into the flow channel (12), with which this in the direction of a Gas flowing through the ventilator (14) is filtered with regard to particles and / or bacteria or germs. Method according to one of the Claims 10 until 12th , characterized in that the volume flow (V) which has been passed and determined through the flow channel (12) is converted into a total volume (V) in order to calculate the remaining service life of the particle and / or bacteria filter (32) to determine. Method according to one of the preceding claims, characterized in that the volume flow (V) guided through the flow channel (12) is converted to at least one volume value (V) on the basis of a derived variable, preferably that the volume value (V) is in particular a tidal Volume (V _T ) and / or a minute volume (V _M ). Device (10) for determining volume flow (V), pressure (p) and composition of a gas when breathing or ventilating a patient (P), comprising a flow channel (12) which can be connected to a ventilator (14) and through which the gas can flow through, at least one flexible support membrane (16) which is arranged in the flow channel (12) essentially orthogonally to the flow direction (S) of the gas, with at least one first surface (17) of the support membrane (16) Sensor (18) is attached, in particular in the form of a strain gauge or a piezo element, the carrier membrane (16) being deformable within the flow channel (12) as a function of the volume flow (V) of the gas, with a movement of the carrier membrane (16) and / or deformation of the first sensor (18), at least one signal can be generated as a function of the volume flow (V) of the gas, a pressure measuring device (20) which is in the flow channel (12) in particular in the range of whose wall (W) is arranged, with this pressure measuring device (20) being able to measure a static pressure (p) for the gas flowing inside the flow channel (12) in comparison to the external environment of the flow channel (12), and at least one inside the flow channel (12) arranged in particular catalytic second sensor (24) with which a composition of the gas, in particular selected gases formed from the group of at least oxygen (O ₂ ) and carbon dioxide (CO ₂ ), can be determined. Device (10) according to Claim 15 , characterized by an evaluation unit (26) which is in signal connection with the first sensor (18) attached to the flexible support membrane (16), the pressure measuring device (20) and the in particular catalytic second sensor (24), preferably in a cable connection. Device (10) according to Claim 16 , characterized in that the evaluation unit (26) is programmed in such a way that the measured values from at least one first sensor (18) attached to the flexible support membrane (16), the pressure measuring device (20) and the, in particular, catalytic second sensor (24 ) are received, can be digitized after reception and can be stored in the evaluation unit (26). Device (10) according to one of the Claims 15 until 17th , characterized by a transmission unit (28) which is connected to the evaluation unit (26) and / or to a first sensor (18) attached to the flexible support membrane (16), the pressure measuring device (20) and the, in particular, catalytic second sensor (24) is in signal connection by cable, the transmission unit (28) being designed to transmit the measured values of the first sensor (18), the pressure measuring device (20) and the, in particular, catalytic second sensor (24) or the data received from the evaluation unit (26) to a to send external device preferably wirelessly via a radio link (F) or the like, preferably that the transmitting unit (28) and the evaluation unit (26) are designed to be integrated in a common device. Device (10) according to Claim 18 , characterized in that the external device is designed in the form of a regulating or control device (15), preferably that the regulating or control device (15) is part of a ventilator (14) for patient ventilation, more preferably that the Regulation or control device (15) is in signal connection with a display unit (D). Device (10) according to one of the Claims 15 until 19th , characterized in that the flexible support membrane (16) extends essentially orthogonally to the flow direction (S) of the gas completely along a diameter of the flow channel (12) and at least with its opposite regions (B) on an inner circumferential surface (13) of the flow channel ( 12) is attached. Device (10) according to one of the Claims 15 until 20th , characterized in that at least one laminarization device (30) is arranged within the flow channel (12) and preferably adjoining or in the vicinity of the carrier membrane (16), with which the flow of the gas directed in the direction of the carrier membrane (16) is laminarized, preferably that a laminarization device (30) is arranged upstream and / or downstream of the carrier membrane (16) as seen in the direction of the patient (P). Device (10) according to one of the Claims 15 until 21 , characterized by at least one particle and / or bacteria filter (32) which is arranged within the flow channel (12), preferably that a particle and / or bacteria filter (32) viewed in the direction of the patient (P) upstream and / or is arranged downstream of the carrier membrane (16), more preferably that the particle and / or bacterial filter (32) and the laminarization device (30) are designed as an integrated unit. Device (10) according to one of the Claims 15 until 21 , characterized in that an additional full-area or local coating is applied to at least one surface (17) of the carrier membrane (16) and a first sensor (18) attached to it. Device (10) according to Claim 23 , characterized in that the additional coating has hygroscopic properties. Device (10) according to one of the Claims 15 until 24 , characterized in that the pressure measuring device (20) is equipped with a strain gauge (21) or with a piezo element (22), with the deformation of which the static pressure (p) of the gas within the flow channel (12) can be measured. Device (10) according to one of the Claims 15 until 24 , characterized by a battery or accumulator unit (29) which is electrically connected to the electrical or electronic components of the device (10) for supplying energy, preferably that the capacity of the battery or accumulator unit (34) is selected to be so large that an energy supply for the electrical or electronic components of the device (10) connected to the battery or accumulator unit (34) is guaranteed for a duration of at least 24 hours, preferably at least 36 hours, more preferably at least 48 hours. Device (10) according to one of the Claims 15 until 26th , characterized in that the individual components of the device (10) are integrated in a common housing (36), preferably that the flow channel (12) fulfills the function of a common housing (36) for the other components, more preferably that the Device (10) is designed as a disposable item.

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