Mixing device, respirator or anaesthesia machine comprising a mixing device, and method for producing a mixing device
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- DRAGERWERK AG
- Filing Date
- 2024-07-25
- Publication Date
- 2026-06-03
AI Technical Summary
Existing ventilation and anesthetic devices face challenges in achieving uniform mixing of breathing gas components, leading to concentration differences and false alarms, with existing solutions requiring significant space, high maintenance costs, and negatively impacting dynamic properties due to flow resistance and complex geometries.
A mixing device with a flow channel design featuring a first section with multiple inputs and a second section with a reduced cross-section, inclined to create a vertebral current that spirals around the longitudinal axis, promoting convective transport and even distribution of breathing gas components, reducing pressure drop and dynamic impact.
The device achieves efficient mixing with minimal space requirements, quick concentration adjustments, and reduced pressure drop, while being easy to manufacture and maintain, avoiding the limitations of conventional mixing technologies.
Smart Images
Figure DE2024100660_30012025_PF_FP_ABST
Abstract
Description
[0001] Mixing device, ventilator or anesthesia device with a mixing device and method for producing a mixing device
[0002] The present invention relates to a mixing device for a ventilator or anesthesia device, a ventilator or anesthesia device with a mixing device for mixing at least two respiratory gas components and a method for producing the mixing device.
[0003] Ventilation of a patient using ventilators or anesthesia machines involves supplying the patient with breathing gas. The breathing gas is typically a mixture of two or more breathing gas components. The most commonly used breathing gas components in practice are air and oxygen. The breathing gas components can be obtained from various sources, for example, via a central gas supply to which the ventilator or anesthesia machine is connected at the installation site, via a gas cylinder filled with the respective breathing gas component, and / or via the intake of air from the environment by the ventilator or anesthesia machine itself, known as blower technology.
[0004] The supplied respiratory gas components are mixed in the ventilator or anesthesia device to achieve at least a nearly even distribution of the respiratory gas components. This is primarily necessary to ensure correct subsequent monitoring of the respiratory gas, while for patient safety and successful therapy it is important that the respiratory gas concentration set on the ventilator or anesthesia device is present in the respiratory gas stream. Deviations from the set ratio of the respiratory gas components arise from tolerances in the concentration during the supply of respiratory gas components, particularly when using a gas cylinder, from tolerances in valves regarding the flow rate, and from the measurements taken by the sensors. The sensors used to monitor the properties of the respiratory gas usually only detect local gas properties, such as the concentration of the respective respiratory gas component at the respective measuring point.Local concentration differences can therefore lead to incorrect measurements and trigger false alarms if, for example, the measured gas concentration is too low. Therefore, a mixed breathing gas is desired in which the concentration differences of the respective breathing gas components are as low as possible.
[0005] To produce a mixed breathing gas, mixing devices within a ventilator or anesthesia device are known. These devices comprise a hollow body or a volume into which the breathing gas components are fed for mixing. The size of such a mixing tank is selected such that the residence time of the breathing gas flow is at least long enough for nearly uniform concentrations of the breathing gas components to be established through diffusion. The long residence time means that changes in the concentration of a breathing gas component in the ventilator or anesthesia device occur only slowly, since the mixing tank, as an additional volume, must be filled and flowed through by the breathing gas. This limits the dynamic range of a ventilator or anesthesia device with such mixing volumes during ventilation.
[0006] Motorized mixers are also known from the state of the art. For example, mixing the respiratory gas components is achieved by installing a motorized stirrer in the ventilator or anesthesia device and operating it. The disadvantage of this solution is the associated high cost of the necessary components, as well as their operation and maintenance.
[0007] Both of the aforementioned solutions require a comparatively large amount of space in the ventilator or anesthesia device. This disadvantageously increases the size of such a device. Furthermore, static flow mixers are known from the prior art. US 2016082220 A1 describes a system for respiratory therapy with a static flow mixer. The described static flow mixer is configured to mix multiple respiratory gas components and comprises an inlet and an outlet as well as a first baffle between the inlet and the outlet. Furthermore, the static flow mixer comprises a constriction arranged between a downstream edge of the first baffle and a nearest downstream surface, wherein a length of the constriction is less than a height of the first baffle. This technical solution is intended to uniformly mix respiratory gas components supplied to the static flow mixer.Further static flow mixers are known from EP 1312409 B1 and EP 1426099 B1. The problem with these static flow mixers is that they create additional flow resistance in the respiratory gas flow channel, which adversely affects the dynamic properties of a ventilator or anesthesia device. Furthermore, these static flow mixers require a lot of space and have a complex geometry, which makes their production very complex.
[0008] Based on the solutions known from the prior art and the problems described above, the object of the invention is to create a device that produces a mixed respiratory gas consisting of at least two respiratory gas components for use in a ventilator or anesthesia device in a simple and reliable manner. The dynamic properties of the ventilator or anesthesia device for ventilation should be affected as little as possible. In particular, a change in the concentration of one of the respiratory gas components in the ventilator or anesthesia device should be induced as quickly as possible and with the smallest possible pressure drop.
[0009] The above object is achieved by a mixing device having the features of claim 1 and by a ventilator or anesthesia device according to claim 10, which has a mixing device. Furthermore, the object is achieved by a method for producing a mixing device having the features of claim 11. Further details of the invention emerge from the subclaims, the description and the drawings. Features and details described in connection with the device according to the invention are of course also deemed to be disclosed in connection with the ventilator or anesthesia device according to the invention, which has such a mixing device, and the method according to the invention, so that with regard to the disclosure, reciprocal reference is always made, or rather can be made, to the individual aspects of the invention.
[0010] The mixing device according to the invention for a ventilator or anesthesia device for mixing at least two respiratory gas components comprises a flow channel which has a first flow channel section with at least two inlets, each of which is suitable for introducing the respiratory gas components, i.e. air and / or gas flows, and a second flow channel section with an outlet for discharging a respiratory gas flow comprising the mixed respiratory gas components.The mixing device is characterized in that a cross section of the first flow channel section decreases at least in sections downstream in the direction of a transition from the first to the second flow channel section, the first and the second flow channel section are inclined towards one another at least in the region of the transition and the first flow channel section opens into the second flow channel section in the region of the transition in such a way that a vortex flow of the respiratory gas flow is at least partially formed around a longitudinal center axis of the second flow channel section in the second flow channel section, which vortex flow flows at least in sections in a spiral manner in the direction of the outlet.
[0011] The core of the invention is to mix the at least two respiratory gas components, which are at least part of an air and / or gas flow, so that a respiratory gas flow is created with almost evenly distributed respiratory gas components and thus there are at least virtually no differences in the concentrations of the individual respiratory gas components across the flow cross-section. This is achieved by the two sections of the flow channel according to the invention, which are designed and arranged in such a way that a vortex flow with the respiratory gas components forms in the second flow channel section, which spreads at least partially in the flow direction in the form of a flow spiral or flow roller.The air, gas, and / or gas mixture flowing in the region of the second flow channel section is thus at least partially set in motion, rotating around a longitudinal center axis of the second flow channel section and simultaneously directed toward the outlet of the flow channel. This effectively mixes the breathing gas components.
[0012] Examples of breathing gas components are air and oxygen. However, other gases, gas mixtures, or gas-air mixtures used for ventilation, anesthesia, and / or at least temporary sedation of a patient in a ventilator and / or anesthesia device are also conceivable.
[0013] A vortex flow, sometimes also called a vortex roller, describes a rotating flow motion of a fluid around a rotational axis, with the fluid moving downstream in the longitudinal direction of the rotational axis at least nearly parallel to or inclined to it. It can be created, for example, by deliberately steering the flow and / or applying an external force.
[0014] The transport of a respiratory gas component in a respiratory gas stream can generally be described by the following transport equation:
[0015] The first term — (pY) describes the change over time, the second term V■(pYjU) the convective transport, the third term V■(pDjjVYj) the diffusive transport and the last term Wj sources or sinks. The diffusive transport mechanism is comparatively weak and is inhibited by long diffusion paths and small transport coefficients. For example, in a mixing tank, diffusive transport predominantly takes place. Therefore, a comparatively long residence time of the breathing gas components in the mixing tank is necessary to achieve the desired mixing of different breathing gas components and leads to the disadvantages described above.
[0016] In contrast to the diffusive transport mechanism, convective transport is considered a very powerful transport mechanism. According to the invention, this transport mechanism is advantageously utilized by deliberately generating a vortex flow to mix various respiratory gas components.
[0017] The various breathing gas components, which can be air, a gas, or a gas mixture, are introduced into the mixing device via at least two inlets. More than two inlets are conceivable, especially if more than two breathing gas components are to be mixed together.
[0018] The inlets are arranged on the flow channel, for example, in such a way that the respiratory gas component streams run spatially adjacent to one another within the first flow channel section, forming a stratified flow of the respiratory gas components. In the area of the contact surfaces where the respiratory gas component streams adjoin one another, the different respiratory gas components are already at least partially mixed through diffusion processes. The stratified flow of the respiratory gas components flows toward the transition from the first to the second flow channel section.
[0019] It is further conceivable for the inlets to be arranged on the flow channel in such a way that the respiratory gas component flows at least partially intersect within the first flow channel section and / or the individual respiratory gas component flows are deflected. The preferably stratified flow, i.e. the flow in which different respiratory gas component flows are arranged in layers, is accelerated by the decreasing cross-section of the first flow channel section and is guided with a higher flow momentum in the region of the transition, for example tangentially, into the second flow channel section. In this case, tangential introduction means that the stratified flow is introduced only at a partial area of the inner wall of the second flow channel section, i.e. not centrally or across the entire cross-section of the second flow channel section.After being introduced into the second flow channel section, the stratified flow initially flows only along a portion of the inner wall of the second flow channel section, while other areas of the inner wall have little or no contact with the stratified flow, either immediately or during the formation of the vortex flow. Thus, the stratified flow essentially touches the inner wall of the second flow channel section upon inflow and exhibits an asymmetric distribution in the transition region of the second flow channel section.The reduction in the cross-section of the first flow channel section can preferably be achieved by reducing the circumference of the first flow channel section itself or by introducing at least one additional flow-guiding element into the first flow channel section, which deflects a portion of the stratified flow and guides it through a smaller flow channel cross-section than that of the first flow channel section. Furthermore, it is conceivable for this additional element to guide the stratified flow into the second flow channel section in such a way that, as described above, a vortex flow is formed.
[0020] According to the invention, the acceleration and the tangential initiation of the stratified flow, i.e., the directed initiation of the stratified flow along a partial region of the inner wall of the second flow channel section, and the inclination between the first and second flow channel sections lead to the formation of a vortex flow within the second flow channel section. The inclination of the second flow channel section relative to the first flow channel section means that their longitudinal center axes are inclined to one another at an angle other than zero. As a result, the stratified flow running along a partial region of the inner wall of the second flow channel section encounters at least one inner wall region of the second flow channel section inclined relative to this partial region, undergoes at least a partial deflection, and a vortex flow forms.It is further conceivable that, alternatively or in addition to the preferred tangential introduction, the stratified flow is introduced into the second flow channel section in such a way that it initially does not run, or only partially runs, along a partial region of the inner wall or along several regions of the inner wall. It is important that, as it continues along the second flow channel section, the stratified flow at least partially encounters a further inner wall region that is at least partially inclined to the flow direction, is deflected in the process, and at least partially forms a vortex flow. For example, by directing the accelerated, stratified flow centrally at the transition from the first to the second flow channel section and, due to the inclination of the second flow channel section to the first flow channel section, encounters one of the inner wall regions of the second flow channel section as it continues.
[0021] According to the invention, the layered flow of the respiratory gas components of the first flow channel section in the first flow section becomes at least partially a vortex flow in the second flow channel section, with several of these layers of respiratory gas components being placed next to one another by the rotational movement of the vortex flow, thus multiplying the adjacent layers of different respiratory gas components. For example, the initial two layers of two different respiratory gas components in the layered flow result in four, six, or more layers of two respiratory gas components in the cross-section of the vortex flow.The respiratory gas components are thus distributed through convective transport by means of the vortex flow in the second flow channel section, and the contact area where the various respiratory gas component streams adjoin one another is increased, resulting in increased mixing of the respiratory gas components through diffusion. The vortex flow flows, at least in sections, spirally toward the outlet, where a mixed respiratory gas stream is formed through convective transport of the various respiratory gas components. This advantageously results in a compact mixing device and minimal impact on the dynamic properties of a ventilator or anesthesia device.
[0022] Various respiratory gas components can be advantageously mixed using such a mixing device. The required installation space is significantly reduced compared to a conventional mixing tank of a ventilator or anesthesia device, enabling a smaller design and a larger dynamic range of a ventilator or anesthesia device. Setting changes on a ventilator or anesthesia device, such as a change in the concentration of one of the respiratory gas components, can thus be implemented quickly and with a minimal pressure drop. Furthermore, the design is simpler to manufacture than a static mixer. In contrast to motor-driven mixers, no active drive, the associated more complex design and increased energy consumption, is required, and the vortex flow is generated solely by the simpler design of the mixing device according to the invention and the existing flow.Thus, the mixing device can be manufactured easily and the manufacturing costs are kept within an economically reasonable range.
[0023] In a preferred embodiment, the first flow channel section and the second flow channel section are arranged almost perpendicular to one another in the transition region. The inclination of the flow channel sections relative to one another serves to create a vortex flow in the second flow channel section. An inclination of the first and second flow channel sections of almost 90° is particularly advantageous for the formation of the vortex flow. The longitudinal center axes are almost perpendicular to one another and, due to the inclination, the stratified flow of the first flow channel section strikes an edge region of the second flow channel section in the flow direction, is thereby deflected and a vortex flow is formed. The vortex flow is particularly pronounced when the first and second flow channel sections are arranged almost perpendicular to one another, so that the mixing of the various breathing gas components is also improved.Furthermore, a particularly stable vortex flow is formed as the fluid continues to flow through the second flow channel section, the flow direction running around the longitudinal center axis of the second flow channel section, the longitudinal center axis thus essentially forming the center of the vortex flow, and thus flowing in the direction of the outlet in a manner adapted to the geometry of the second flow channel section.
[0024] A further advantage of the almost vertical arrangement of the first and second flow channel sections is a more compact design and thus a space saving when installed in a ventilator or anesthesia device.
[0025] According to a particularly preferred embodiment of the mixing device, the first flow channel section and / or the second flow channel section have a rectangular cross-section, at least in sections. It is conceivable for the cross-section to be rectangular or, particularly preferably, square. This provides the advantage of improved utilization of the installation space when installing the mixing device in a ventilator or anesthesia device. An at least partially rectangular cross-section of the second flow channel section is particularly advantageous, with the swirling flow in the four corners within the second flow channel section creating secondary vortices that improve the mixing of the various respiratory gas components.
[0026] In a preferred embodiment of the mixing device, the first flow channel section and / or the second flow channel section is / are at least partially configured in the shape of a cylinder, a truncated cone, or a truncated pyramid. A substantially circular cross-section of the first and / or second flow channel section has the advantage that, for example, breathing gas hoses are easier to attach to the inlets and / or outlet of the mixing device. An at least partially circular cross-section of the second flow channel section is particularly advantageous, forming a particularly stable vortex flow which, at least partially, flows in a spiral shape and guided by the second flow channel section toward the outlet.
[0027] According to a preferred embodiment of the mixing device, the at least two inlets have a nearly circular cross-section. This has the advantage that breathing gas hoses can be particularly easily attached to the inlets.
[0028] In a preferred embodiment of the mixing device, the cross-section of the first flow channel section decreases by more than 50% up to the transition to the second flow channel section. Preferably, the cross-section decreases uniformly from the region of the inlets up to the transition to the second flow channel section. Furthermore, it is conceivable for the reduction in the cross-section to affect only a partial area of the first flow channel section. For example, the cross-section decreases by more than 50% from the center of the first flow channel section up to the transition to the second flow channel section. It is also conceivable for the reduction in the cross-section to occur only shortly before the transition to the second flow channel section.
[0029] The particular advantage of reducing the cross-section by more than 50% is that the resulting flow momentum of the stratified flow is strong enough to promote the formation of vortex flow in the second flow channel section. This advantageously generates vortex flow, particularly for typical volume flows of a ventilator or anesthesia device in the range of 1 l / min to 180 l / min.
[0030] According to a preferred embodiment of the mixing device, the first flow channel section and / or the second flow channel section comprise a mixing element for mixing the respiratory gas components. Mixing elements can, for example, be static mixers or similar geometries that are integrated into the first and / or second flow channel section. The stratified flow of the first flow channel section and / or the vortex flow of the second flow channel section encounters a mixing element, and additional mixing of the respiratory gas components takes place. Advantageously, improved mixing of the respiratory gas components at the outlet of the mixing device is achieved by a suitable mixing element, without enlarging the mixing device and without having to provide additional space when installed in a ventilator or anesthesia device.The outer dimensions of the mixing element should correspond to or be smaller than the inner circumference of the first or second flow channel section. Furthermore, the mixing element should exhibit the lowest possible flow resistance. It is conceivable to integrate one or more mixing elements into the first and / or second flow channel section. Furthermore, it is conceivable for the mixing elements within the mixing device to have a different structure.
[0031] In a preferred embodiment of the mixing device, the at least two inlets are arranged substantially adjacent to one another, resulting in a stratified flow of the respiratory gas components in the first flow channel section. Such an arrangement of the inlets results in a special stratified flow in which the respiratory gas component streams run substantially adjacent to one another and their flow velocity remains virtually constant, thus preventing the flow from being attenuated. This advantageously promotes the formation of a vortex in the second flow channel section.
[0032] According to a preferred embodiment of the mixing device, a buffer volume is arranged downstream of each of the at least two inlets of the first flow channel section, and a cross-section of the buffer volumes is substantially circular. The buffer volumes are preferably cylindrical, and the respiratory gas component streams preferably flow directly from the inlets into the buffer volumes. The cross-sections of the buffer volumes preferably correspond to the cross-section of the respective inlet, so that the respective buffer volume can be filled as quickly as possible with the inflowing respiratory gas component. The buffer volumes preferably each have a size in the range of 25 to 35 ml, particularly preferably 30 ml. The respiratory gas component streams are introduced via the inlets into a respective buffer volume, which fills with the corresponding respiratory gas component.When the respiratory gas component streams exit the buffer volumes within the first flow channel section, a stratified flow also forms. This can be achieved, for example, by the arrangement of the buffer volume outlets or by the shape of the first flow channel section. Furthermore, fluid communication exists between the buffer volumes in the form of a flow channel that opens tangentially into the buffer volumes. An exchange of the respective respiratory gas components takes place between the buffer volumes through the flow channel, with a respiratory gas component flow flowing via the flow channel from one buffer volume to the other. It is conceivable to close the flow channel between the buffer volumes if an exchange across it is not necessary.
[0033] The invention further relates to a ventilator or anesthesia device with a mixing device designed according to one of the previously described embodiments. The respiratory gas components required for ventilation are fed into the ventilator or anesthesia device, for example, via a central gas supply, a blower, and / or a connected gas cylinder, and are prepared according to the patient's needs. This includes, for example, setting a specific oxygen concentration, which is fed into the mixing device with air, for example, so that the previously set oxygen concentration is achieved in the respiratory gas stream ultimately formed at the outlet of the mixing device.The mixing device mixes the respiratory gas components, for example oxygen and air, and enables precise determination of the concentration of a respiratory gas component in the respiratory gas stream flowing out of the mixing device via the outlet, since the different respiratory gas components are distributed almost evenly across the flow cross-section. The respiratory gas component streams, for example air, oxygen and / or an anesthetic gas, are guided into the first flow channel section via the inlets of the mixing device. It is conceivable that the mixing device has more than two inlets and can thus mix more than two respiratory gas components, for example three respiratory gas components or more. The respiratory gas component streams in the first flow channel section experience an acceleration on the way to the transition to the second flow channel section, which is achieved by at least partially reducing the cross-section of the first flow channel section.The acceleration causes an increase in the flow momentum and, together with a directed introduction of the respiratory gas component flows into the second flow channel section, contributes to the formation of a vortex flow. The respiratory gas component flows are preferably guided tangentially into the second flow channel section. The second flow channel section is arranged at an angle to the first flow channel section, so that the introduced respiratory gas component flows impinge on an inner wall region of the second flow channel section which is at least partially opposite the transition from the first to the second flow channel section, i.e. an outlet of the first flow channel section, in the flow direction. As a result, the respiratory gas component flows are deflected and set into a rotating movement around a longitudinal center axis of the second flow channel section, and a vortex flow is formed.The vortex flow flows, at least in sections, in a spiral pattern toward the outlet of the mixing device. The advantageously mixed respiratory gas flow leaves the mixing device via the outlet and flows, for example, past an oxygen sensor to determine the oxygen concentration before the mixed respiratory gas flow is supplied to the patient. Due to the particularly good mixing of the respiratory gas components in the respiratory gas flow, false alarms due to concentration gradients present in the respiratory gas flow and the local concentration peaks caused thereby can be avoided. Furthermore, a measured respiratory gas concentration without such concentration peaks due to insufficient mixing simplifies control of the concentration ratio of the respiratory gas components, since in this case the concentration values do not need to be averaged and / or filtered.
[0034] Furthermore, the invention relates to a method for producing such a mixing device, wherein at least one manufacturing step is part of an injection molding process or 3D printing process. The injection molding process is advantageous for the production of a large number of mixing devices. The 3D printing process is advantageous for the fastest possible production. The mixing device according to the invention is designed so that both manufacturing processes can be implemented with little effort.
[0035] Further features, objects, and effects of the invention will become apparent from the description and the accompanying figures. Exemplary embodiments of the invention are described without limiting the general inventive concept.
[0036] In the figures shows:
[0037] Fig. 1 : a schematic, transparent representation of a mixing device with streamline representation of the breathing gas flow,
[0038] Fig. 2: a schematic representation of a section of the flow channel sections of a mixing device with streamline representation of the respiratory gas flow,
[0039] Fig. 3: a schematic representation of a preferred embodiment of a mixing device with buffer volume, and Fig. 4: a schematic representation of a preferred embodiment of a mixing device with mixing elements.
[0040] Embodiments of the invention are described in detail below with reference to the accompanying figures. Similar components in several figures are provided with the same reference numerals.
[0041] Fig. 1 shows a preferred embodiment based on a schematic representation of a mixing device 1, wherein the housing of the mixing device 1 is shown transparently and the streamlines 13a, 13b, 13c, 14a, 14b, 14c of the flowing respiratory gases are additionally shown. Three exemplary streamlines 13a, 13b, 13c of a first respiratory gas component stream and three streamlines 14a, 14b, 14c of a second respiratory gas component stream are shown, wherein the streamlines of the two respiratory gas component streams mix to form one respiratory gas stream, as described below. The mixing device 1 comprises a first inlet 2 and a second inlet 3 for introducing two respiratory gas components, a first flow channel section 4, a second flow channel section 5 and a transition 6 from the first to the second flow channel section 4, 5. Furthermore, the mixing device 1 has an outlet 7 for discharging the mixed respiratory gas.
[0042] In the exemplary embodiment in Fig. 1, the respiratory gas components air and oxygen are mixed. Air is introduced into the first flow channel section 4 through the first inlet 2, and oxygen is introduced through the second inlet 3. The design of the first inlet 2 and the second inlet 3 causes the respiratory gas component flows of air and oxygen to run essentially alongside one another in the first flow channel section 4, forming a stratified flow 11 with a region in which the respiratory gas component flows adjoin one another. The cross-section of the first flow channel section 4 decreases downstream to the transition 6, thereby accelerating the stratified flow. The accelerated, stratified flow 11 then flows tangentially into the second flow channel section 5.The stratified flow is introduced into the second flow channel section 5 by reducing the cross-section of the first flow channel section 4 in such a way that it initially runs primarily along a first inner wall region 9. The stratified flow 11 then encounters a second inner wall region 10, which is arranged almost perpendicular to the flow direction of the stratified flow 11. As a result, the stratified flow 11 is deflected in such a way that a vortex flow 12 forms, i.e., a flow that runs in a circle around an axis. The vortex flow 12 flows spirally around a longitudinal center axis 8 of the second flow channel section 5 in the direction of the outlet 7, with the breathing gas components air and oxygen mixing within the vortex flow 12.
[0043] Fig. 2 shows a schematic representation of a section of the flow channel sections of the mixing device 1, including a streamline representation of the respiratory gas flow 21, 22. A lateral view of the mixing device is shown, which shows a plan view in the direction of the longitudinal center axis 8 of the second flow channel section 5 according to Fig. 1. The respiratory gas components air and oxygen are guided via the first inlet 2 and the second inlet 3 into the first flow channel section 4, in which a first respiratory gas component flow 21 and a second respiratory gas component flow 22 are formed. The layered respiratory gas component flows 21, 22, which have a flat contact area, flow in the direction of the arrow to the transition 6 and from the first into the second flow channel section 4, 5, wherein they experience acceleration due to a reduction in the cross-section of the first flow channel section 4.Due to this acceleration, the respiratory gas component streams 21, 22 receive an increased flow momentum and are guided into the second flow channel section 5, which is inclined relative to the first flow channel section 4, so that the layered respiratory gas component streams 21, 22 encounter an inner wall region of the second flow channel section 5, are deflected, and finally a vortex flow 12 forms, which propagates in the direction of the outlet 7. Within the vortex flow 12, the adjacent contact surfaces of the layered respiratory gas component streams 21, 22 multiply, whereby the various respiratory gas components, air and oxygen, mix in a particularly advantageous manner. The reason for this is the convective transport of the respiratory gas components of the respiratory gas component streams 21, 22 caused by the vortex flow 12.Due to this convective transport, as a particularly strong transport mechanism, the respiratory gas components are distributed almost evenly in the second flow channel section 5, whereby the contact area of the respiratory gas component flows 21, 22 is increased and an increased mixing of the respiratory gas components takes place by diffusion.
[0044] Fig. 3 shows a schematic representation of a preferred embodiment of a mixing device 30 according to the invention. For better clarity, part of the mixing device 30 has been hidden so that the internal structure can be seen. The mixing device 30 comprises a first inlet 2 and a second inlet 3 for introducing two respiratory gas components, a first flow channel section 4, a second flow channel section 5, a transition 6 from the first to the second flow channel section 4, 5 and an outlet 7 for discharging the mixed respiratory gas. The mixing device 30 further comprises a first buffer volume 31, which is arranged downstream of the first inlet 2 in the flow direction, and a second buffer volume 32, which is arranged downstream of the second inlet in the flow direction, as well as a flow channel 34 between the buffer volumes 31, 32. In addition, a flow-guiding element 33 is integrated in the first flow channel section 4.This flow-guiding element 33 reduces the cross-section of the first flow channel section 4 and changes the direction of the first flow channel section 4 such that respiratory gas component flows from the first flow channel section 4 are guided tangentially into the second flow channel section 5, forming a vortex flow in the second flow channel section 5. In this vortex flow, various respiratory gas components mix, and a mixed respiratory gas flow exits the mixing device 30 via the outlet 7.
[0045] Fig. 4 shows a schematic representation of another preferred embodiment of a mixing device 40 designed according to the invention, wherein the mixing device 40 is shown transparent for better clarity. The mixing device 40 also comprises a first inlet 2 and a second inlet 3 for introducing two respiratory gas components, a first flow channel section 4, a second flow channel section 5, a transition 6 from the first to the second flow channel section 4, 5 and an outlet 7 for discharging the mixed respiratory gas. In this exemplary embodiment, a first mixing element 41 is integrated in the first flow channel section 4 and a second mixing element 42 is integrated in the second flow channel section. The first and second mixing elements 41, 42 are designed in the form of static mixers that have no moving parts.The first mixing element 41 effects additional mixing of the various respiratory gas components by deflecting the stratified flow 11, which contains the respiratory gas component flows 21, 22, as shown in Fig. 2, in different directions, so that the respiratory gas component flows cross, thus creating distribution and mixing of the respiratory gas components already in the first flow channel section 4. In a similar way, additional mixing of the respiratory gas components within the vortex flow 12, as shown, for example, in Fig. 1, is created by a second mixing element 42 in the second flow channel section 5. There, the vortex flow 12 is guided through a network of multiple flow channels running in different directions, whereby the respiratory gas components are also distributed and additional mixing occurs.
[0046] 1 mixing device
[0047] 2 first entry
[0048] 3 second entrance
[0049] 4 first flow channel section
[0050] 5 second flow channel section
[0051] 6 Transition
[0052] 7 Outlet
[0053] 8 Longitudinal center axis
[0054] 9 first interior wall area
[0055] 10 second interior wall area
[0056] 11 stratified flow
[0057] 12 vortex roller
[0058] 13a, 13b, 13c Streamlines of a first respiratory gas component flow
[0059] 14a, 14b, 14c Streamlines of a second respiratory gas component flow
[0060] 21 first respiratory gas component flow
[0061] 22 second breathing gas component flow
[0062] 30 preferred embodiment of a mixing device
[0063] 31 first buffer volume
[0064] 32 second buffer volume
[0065] 33 flow-guiding element
[0066] 34 Flow channel between the buffer volumes
[0067] 40 further preferred embodiment of a mixing device
[0068] 41 first mixing element
[0069] 42 second mixing element
Claims
Patent claims 1. A mixing device (1) for a ventilator or anesthesia device for mixing at least two respiratory gas components, comprising a flow channel having a first flow channel section (4) with at least two inlets (2, 3) for introducing the respiratory gas components and a second flow channel section (5) with an outlet (7) for discharging a respiratory gas stream comprising the mixed respiratory gas components, characterized in that a cross-section of the first flow channel section (4) decreases at least in sections downstream in the direction of a transition (6) from the first to the second flow channel section (4, 5), the first and second flow channel sections (4, 5) are inclined toward one another at least in the region of the transition (6), and the first flow channel section (4) opens into the second flow channel section (5) in the region of the transition (6),that at least partially a vortex flow (12) of the respiratory gas flow is formed around a longitudinal center axis (8) in the second flow channel section (5), which at least partially flows spirally in the direction of the outlet (7).
2. Mixing device (1) according to claim 1, characterized in that the first flow channel section (4) and the second flow channel section (5) are arranged almost perpendicular to one another in the region of the transition (6).
3. Mixing device (1) according to claim 1 or 2, characterized in that the first flow channel section (4) and / or the second flow channel section (5) have a rectangular cross-section at least in sections.
4. Mixing device (1) according to claim 1 or 2, characterized in that the first flow channel section (4) and / or the second flow channel section (5) is formed at least in sections in the form of a cylinder, a truncated cone or a truncated pyramid.
5. Mixing device (1) according to one of the preceding claims, characterized in that the at least two inlets (2, 3) have an almost circular cross-section.
6. Mixing device (1) according to one of the preceding claims, characterized in that the cross section of the first flow channel section (4) is reduced by more than 50% up to the transition (6) to the second flow channel section (5).
7. Mixing device (1) according to one of the preceding claims, characterized in that the first flow channel section (4) and / or the second flow channel section (5) comprises a mixing element (41, 42) for mixing the breathing gas components.
8. Mixing device (1) according to one of the preceding claims, characterized in that the at least two inlets (2, 3) are arranged substantially next to one another, resulting in a stratified flow (11) of the respiratory gas components in the first flow channel section (4).
9. Mixing device (1) according to one of the preceding claims, characterized in that a buffer volume (31, 32) is arranged downstream of each of the at least two inlets (2, 3) of the first flow channel section (4), a cross section of the buffer volumes (31, 32) is substantially circular, and that between the buffer volumes (31, 32) there is fluid communication in the form of a flow channel (34) which opens tangentially into the buffer volumes (31, 32).
10. Ventilation or anesthesia device with a mixing device (1) according to at least one of the preceding claims.
11. A method for producing a mixing device (1) according to one of claims 1 to 9, wherein at least one manufacturing step is part of an injection molding process or 3D printing process.