Respiratory flow sensor

Abstract

To provide a respiratory flow sensor which has a compact design and can be produced easily and with high quality.SOLUTION: A respiratory flow sensor 11 comprises: a flow tube 12 having a longitudinal axis 14, a first flow tube portion 21 and a second flow tube portion 41; a flow resistor 61 arranged in a flow channel 13 between the first flow tube portion 21 and the second flow tube portion 41; and two connection portions 32, 52 for taking in a pressure difference generated by the flow resistor 61. The first connection portion 32 the first flow tube portion 21 via a first connection line and is provided in the first flow tube portion 21. The second connection portion 52 communicates with the second flow tube portion 41 via a second connection line and is provided in the second flow tube portion 41. The connection portions 32, 52 respectively have connection line portions 33, 53 which extend essentially parallel to the longitudinal axis 14 of the flow tube 12. The openings 35, 55 of the connection portions 32, 52 are oriented in the same direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a respiratory flow sensor, a respiratory adapter, and a method for manufacturing a respiratory flow sensor.

Background Art

[0002] A respiratory flow sensor, also called a differential pressure flow sensor, a flow measurement sensor, or a flow sensor, is disposed between a tube exiting from a ventilator or an anesthesia machine and a tube supplied to a patient.

[0003] A respiratory flow sensor comprising a flow tube having a longitudinal axis, a first flow tube portion, and a second flow tube portion, and a tube connection for a tube in the region of the free end is known from US Patent No. 4,403,514 A. A flow resistance is disposed in the flow tube between the first flow tube portion and the second flow tube portion. Also, a radially protruding connection portion for taking in the pressure difference generated by the flow resistance is provided. Connection tubes connectable to a measuring device are provided at these connection portions. The connection portions are provided in the first flow tube portion and communicate with the first flow tube portion via a first connection line. Further connection portions are provided in the second flow tube portion and communicate with the second flow tube portion via a second connection line.

[0004] The disadvantage of this known solution is that the connection lines arranged at the connection portions may break, which can lead to errors in the measurement results under certain circumstances.

[0005] A respiratory flow sensor comprising a flow tube having a longitudinal axis, a first flow tube section, and a second flow tube section is known from CH No. 701 755 B1. A flow resistance is placed in the flow tube between the first and second flow tube sections. A connection is also provided for taking in the pressure difference generated by the flow resistance. The first connection leads to the first flow tube section via a first connection line, and a further connection leads to the second flow tube section via a second connection line. Both connection sections are provided in the first flow tube section. Each connection section has a connection line section of a connection line extending parallel to the longitudinal axis of the flow tube. The openings of the connection sections are oriented in the same direction.

[0006] The drawback of this known solution is that, in addition to requiring a flange extension that projects radially, i.e., outward, to form a connection line from the connection point to the corresponding flow tube, complex structural and manufacturing techniques are required in the design of the sealing means to ensure a sealed connection. This is the only way to prevent air short circuits, which can lead to significant errors in measurement results when using a respiratory flow sensor.

[0007] DE No. 20 2017 102 703 U1 illustrates a flow sensor having a flow tube with a longitudinal axis, a first tubular element, and a second tubular element. Furthermore, the flow sensor has a flow resistance positioned in the flow tube between the first and second tubular elements. Extension tubes for taking in the pressure difference generated by the flow resistance are positioned on the tubular elements, with the first extension tube passing into the first tubular element and a further extension tube passing into the second tubular element. The first extension tube is positioned on the first tubular element, and the further extension tube is positioned on the second tubular element.

[0008] The drawback of this solution is that the extension tube essentially protrudes radially from the flow sensor, and consequently, the measuring tube placed there also essentially protrudes radially during use. As a result, this flow sensor occupies a relatively large space during use. This makes handling the flow sensor cumbersome for the user.

[0009] A respiratory flow sensor is known from US Patent No. 6,585,662 B1, which is nearly identical in structural design to the respiratory flow sensor of CH Patent No. 701,755 B1, but has a far more practical design. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] U.S. Patent No. 4403514 [Patent Document 2] Swiss Patent No. 701755 [Patent Document 3] German Utility Model Registration No. 202017102703 Specification [Patent Document 4] U.S. Patent No. 6,585,662 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] Therefore, the objective of the present invention is to create a respiratory flow sensor that does not have at least some of the aforementioned drawbacks, has a very compact design, and can be easily and with high quality manufacture. [Means for solving the problem]

[0012] This objective is achieved by the features of the independent claim. Further advantageous developments are described in the drawings and dependent claims.

[0013] According to the present invention, the respiratory flow sensor comprises a longitudinal axis, a flow tube having a first flow tube section and a second flow tube section, a flow resistance disposed between the first flow tube section and the second flow tube section within the flow tube, and a connection section for taking in the pressure difference generated by the flow resistance. The first connection section leads to the first flow tube section via a first connection line. A further connection section leads to the second flow tube section via a second connection line, and each connection section has a connection line section of a connection line that extends essentially parallel to the longitudinal axis of the flow tube, and the openings of the connection sections are oriented in the same direction. The first connection section is provided on the first flow tube section, and the further connection section is provided on the second flow tube section.

[0014] In this context, the phrase "essentially parallel to the longitudinal axis of the pipe" is understood to mean, on the one hand, a mathematically defined parallel alignment with respect to this longitudinal axis, but also an alignment that deviates from it by a few degrees.

[0015] The two connection points of the respiratory flow sensor itself are positioned essentially parallel to each other, which is advantageous as it allows the respiratory flow sensor to be made thinner.

[0016] Each connection point for capturing the pressure difference generated by flow resistance is provided in each flow tube, and the corresponding connection line leads into the interior of that flow tube. Therefore, when the flow tubes are assembled, care must be taken to seal the flow paths within the flow tubes so that the individual parts of the respiratory flow sensor can be assembled easily and with a simpler structure. This avoids the need to guide additional air in the connection lines, which ensures and further improves the measurement accuracy compared to previously known respiratory flow sensors.

[0017] The connection lines are advantageously designed to be seamless. In other words, it is advantageous that each connection line has no seams from the opening of the connection point to the opening of the respective flow tube. This avoids effects that could negatively affect the measurement and further improves the accuracy of the measurement.

[0018] The connection part for incorporating the pressure difference generated by the flow resistance can be arranged near the outside of the housing of the respiratory flow sensor while ensuring the connection of the connection tube, thereby enabling a very compact design of the entire respiratory flow sensor.

[0019] The respiratory flow sensor preferably comprises two housing parts, namely a first flow tube part and a second flow tube part that enable easy assembly of the respiratory flow sensor.

[0020] The respiratory flow sensor further preferably consists of injection-molded parts or is itself an injection-molded part. Injection-molded parts can be manufactured economically, especially in large quantities, and can be easily assembled as required.

[0021] More preferably, the respiratory flow sensor is made of a plastic suitable for medical applications, thereby enabling, for example, omission of an additional coating inside the flow tube.

[0022] Preferably, each connection line has a further connection line part that extends at least partially linearly and intersects a connection line part that extends essentially parallel to the longitudinal axis of the flow tube. This enables a structurally simple design of the connection line.

[0023] Preferably, the further connection line part of this connection line that extends at least partially linearly intersects the connection line part of the connection line that extends essentially parallel to the longitudinal axis of the flow tube at an angle of 40° to 70°. This enables easy manufacture of the respiratory flow sensor, especially as an injection-molded part, while ensuring good air guidance.

[0024] Preferably, the first flow tube part has an essentially cylindrical part and a radially expanding part, and the radially expanding part expands towards the open end of the first flow tube part. Thus, the second flow tube part can be arranged on the first flow tube part in a simple manner.

[0025] Alternatively or additionally, the second flow tube portion has an essentially cylindrical portion and a radially expanding portion that expands towards the open end of the second flow tube portion. Thus, the first flow tube portion can be easily disposed in the second flow tube portion, and the two flow tube portions can be arranged in a simple manner so as to be sealed against each other.

[0026] In particular, radially protruding flanges having contact surfaces are provided at the open ends of the first and second flow tube portions, respectively, such that the diameter of this region is larger, and this arrangement is simplified with the aid of the two contact surfaces of the two flow tube portions.

[0027] Preferably, there is a first connection recess on the radially expanding portion of the first flow tube portion for at least partially receiving a further connection portion of the second flow tube portion. Thus, the further connection portion of the second flow tube portion can be easily disposed within this first connection recess, resulting in a reduction in the size of the respiratory flow sensor and enabling a respiratory flow sensor that is as compact as possible.

[0028] In particular, the first connection recess is disposed on a radially protruding flange of the first flow tube portion. The first flow tube portion has improved stability in the region of the radially protruding flange, and as a result, the first connection recess may also have improved stability or strength.

[0029] Advantageously, there is a first support structure on the radially expanding portion of the first flow tube portion for supporting a further connection portion of the second flow tube portion, such that this further connection portion has an enlarged contact surface and is thus received in a mechanically more stable manner, for example, without breaking.

[0030] Advantageously, the further connection of the second flow tube section has a support, which, advantageously, can use this support to abut against a first connection recess on the radially extending portion of the first flow tube section. Thus, the further connection section is stably held within this connection recess. This further prevents, for example, breakage of the further connection section due to external mechanical loads.

[0031] Alternatively, or as an addition, there is a further connecting recess on the radially extending portion of the second flow tube to at least partially receive the first connection of the first flow tube. Thus, the first connection of the first flow tube can be easily positioned within this second connecting recess, which in turn can further reduce the size of the respiratory flow sensor and make the most compact respiratory flow sensor possible.

[0032] In particular, the second connecting recess is provided on a radially projecting flange of the second flow tube. The second flow tube has improved stability in the region of the radially projecting flange, and as a result, the second connecting recess may also have improved stability or strength.

[0033] Advantageously, the second flow section has an additional support structure on its radially extending portion to support the first connection of the first flow section, resulting in improved mechanical stability and, for example, preventing breakage.

[0034] Advantageously, the first connection of the first flow tube section has a support, which can, using this support, abut against a second connection recess on the radially extending portion of the second flow tube section. Thus, the first connection is stably held within this connection recess. This further prevents, for example, breakage of the first connection due to external mechanical loads.

[0035] Preferably, a further portion of one connecting line, which extends at least partially in a linear fashion, intersects at an angle of 48° to 62° with a portion of this connecting line that extends essentially parallel to the longitudinal axis of the flow tube. This allows for easy manufacturing of the respiratory flow sensor, particularly as an injection-molded part, and ensures good air guidance, in addition to reducing the effort required for rework, for example, when removing the respiratory flow sensor.

[0036] Particularly preferably, a further portion of this connecting line, which extends at least partially in a linear fashion, intersects at an angle of 52° to 58° with a portion of this connecting line that extends essentially parallel to the longitudinal axis of the flow tube. This allows the respiratory flow sensor to be optimally configured, in addition to the advantages mentioned above with respect to the stability and material requirements for its manufacture.

[0037] Preferably, a further connection line portion of the other connection line, which extends at least partially in a linear fashion, intersects the connection line portion of the other connection line, which extends essentially parallel to the longitudinal axis of the flow tube, at an angle of 130° to 160°. This allows for easy manufacture of the respiratory flow sensor, particularly as an injection-molded part, while ensuring good air guidance.

[0038] Preferably, a further connection line portion of the other connection line, which extends at least partially in a linear fashion, intersects the connection line portion of the other connection line, which extends essentially parallel to the longitudinal axis of the flow tube, at an angle of 138° to 152°. This ensures easy manufacturing of the respiratory flow sensor, particularly as an injection-molded part, and guarantees good air guidance, as well as reducing the effort required for rework, for example, when removing the respiratory flow sensor.

[0039] Particularly preferably, a further connection line portion of the other connection line, which extends at least partially in a linear fashion, intersects at an angle of 142° to 148° with a connection line portion of the other connection line that extends essentially parallel to the longitudinal axis of the flow tube. In this way, the respiratory flow sensor can be optimally configured, in addition to the advantages described above with respect to the stability and material requirements for its manufacture.

[0040] Preferably, the first connection is positioned adjacent to a further connection. Thus, both connections are located in the same region of the flow tube, which prevents the connecting tube from kinking.

[0041] Preferably, the first connection is positioned adjacent to and at a certain distance from further connection points, so that the connecting tube can be easily connected to each connection point.

[0042] Preferably, the first connection portion is provided at least partially on the outer jacket surface of the first flow tube portion and therefore located outside the housing of the respiratory flow sensor. This allows for easy manufacture of the respiratory flow sensor and ensures an absolute seal connection between the first connection portion and the first flow tube portion. Further groove / comb structures in the area of ​​the further connection line portion may be omitted.

[0043] Alternatively, or as an addition, the additional connection is positioned at least partially on the jacket surface of the second flow tube section, and therefore outside the housing of the respiratory flow sensor. This ensures an absolute seal connection between the second connection and the second flow tube section. Further groove / comb structures in the area of ​​the additional connection line section can be omitted. Thus, the two flow tube sections can be joined in a simple process step, the flow resistance is precisely positioned within the flow tube, and the necessity of an absolute seal connection between the two flow tube sections is ensured.

[0044] Preferably, a tool opening for removing a forming tool for forming a further connection line portion of the connection line and a closing element for closing the tool opening are provided, wherein a first closing element for closing a further connection line portion of the first connection line is preferably provided in the first flow tube portion, and a second closing element for closing a further connection line portion of the second connection line is preferably provided in the second flow tube portion. This allows for easy manufacture of the respiratory flow sensor. When the tool opening is closed, air guidance in the corresponding connection line is ensured without air short circuits.

[0045] Preferably, the first closing element is pivotably mounted on the first flow tube via a hinge, preferably a flexible hinge. Preferably, the second closing element is similarly pivotably mounted on the second flow tube via a hinge, preferably a flexible hinge. Thus, the closing elements are constrained to their respective components. As a result, the closing elements are available throughout the entire assembly of the respiratory flow sensor and can be provided in a manner optimized for closing the tool opening as needed or during the manufacturing process of the respiratory flow sensor.

[0046] The closing element is advantageously made of a material suitable for medical applications, particularly a plastic suitable for medical applications. If the corresponding flow tube section is made of the same material, or a material compatible with respect to the connection technique, the tool opening can therefore be closed in a simple work step.

[0047] The first and / or second closing elements can be designed as plugs that allow the corresponding tool opening to be closed in a simple process step.

[0048] Preferably, groove / comb-shaped structures are provided on the tool opening and / or closing elements, which interlock when joined together, thereby ensuring a high degree of tightness of the closure.

[0049] Preferably, the closing elements are fixed to each flow tube section by a sealing connection, particularly preferably by ultrasonic welding, to close the tool opening, thereby ensuring an absolute tightness of the closure.

[0050] In alternative embodiments, the closing elements for closing the tool openings on each flow tube section are secured by a type of welding other than ultrasonic welding, by a tight fit, or by adhesive bonding.

[0051] In a further alternative embodiment, for example, a two-component solution is provided in the manufacture of a respiratory flow sensor, and at least one of these components, for example in the area of ​​the contact surface, is made of or coated with a softer plastic or a plastic having adhesive properties. When the corresponding parts are put together, they are directly sealed together.

[0052] Such two-component solutions are suitable for components that need to be connected to each other, particularly components that need to be sealed together, during the manufacture of respiratory flow sensors.

[0053] The respiratory adapter according to the present invention comprises at least one respiratory flow sensor having at least one of the features described above, and at least one connecting tube connecting one of the connection parts of the respiratory flow sensor to a measuring device to create a fluid connection from the measuring device to the respiratory flow sensor, wherein the fluid connection is formed directly into one of the flow tubes of the respiratory flow sensor without any joints.

[0054] Advantageously, the measuring device is designed to measure the pressure difference in the respiratory flow sensor.

[0055] This breathing adapter is easy to use and has the advantages described herein in relation to the breathing flow sensor.

[0056] In this context, the term "fluid connection" is understood to mean a circulating and optional seal connection from an inlet point to an outlet point for a fluid, such as air.

[0057] Advantageously, connecting tubes that can be connected to the measuring device are provided at each connection point of the respiratory flow sensor. To simplify the use of the respiratory adapter for the user, the connecting tubes may be optically, for example, color, and / or tactilely distinct.

[0058] Preferably, the breathing adapter comprises at least one ventilator tube and a mouthpiece supplied to the patient, wherein at least one ventilator tube connects the mouthpiece to at least one respiratory flow sensor, thereby creating an easy-to-use breathing adapter.

[0059] Further advantages are provided, which can also be connected to at least one respiratory sensor and connected to a ventilator or intensive care unit, resulting in the user having an easy-to-use respiratory adapter.

[0060] The method according to the present invention for manufacturing a respiratory flow sensor is characterized by the following steps.

[0061] By forming the first and second flow tube sections with manufacturing tool molds, the corresponding connection line sections and further connection line sections are formed by a slider as a forming tool and / or by a pin as a forming tool (step a).

[0062] Alternatively or additionally, further connection line portions of the corresponding connection lines are formed by a pin as a forming tool (step a)).

[0063] The molding tools are placed in, or can be placed in, each manufacturing tool mold, thereby enabling the simple manufacturing of the first and second flow tube sections.

[0064] The first and second flow tube sections are released from their respective manufacturing tool molds (step b).

[0065] Molding tools designed as sliders or pins significantly simplify the demolding of the first and second flow tube sections from their respective manufacturing tool molds.

[0066] The first and second flow tube sections are aligned with respect to each other in terms of axial and angular position (step c), thereby ensuring the precise alignment of these sections with respect to each other and thus the full functionality of the respiratory flow sensor.

[0067] A seal connection between the first and second flow tube sections (step d). The seal connection includes, but is not exhaustive, welding, especially ultrasonic welding, tight fitting, adhesive bonding, or a two-component solution.

[0068] Advantageously, the tool openings at each connection point of the respiratory flow sensor are sealed by ultrasonic welding. When the tool openings are sealed, air guidance in the corresponding connection line is ensured without air short circuits.

[0069] Further advantages, features, and details of the present invention will become apparent from the following description, in which exemplary embodiments of the present invention are described with reference to the drawings.

[0070] The list of reference numerals, as well as the technical content of the claims and drawings, is part of this disclosure. The drawings are described in a consistent and comprehensive manner. The same reference numerals indicate corresponding components, and reference numerals with different numerals indicate functionally identical or similar components. [Brief explanation of the drawing]

[0071] [Figure 1] A first embodiment of the respiratory flow sensor according to the present invention is shown in a perspective view. [Figure 2] Figure 1 shows an exploded perspective view of the respiratory flow sensor. [Figure 3] Figure 1 shows a side view of the first flow tube section of the respiratory flow sensor. [Figure 4] Figure 3 shows a longitudinal cross-sectional view of the first flow pipe section. [Figure 5] Figure 4 shows a detailed cross-section X. [Figure 6] Figure 1 shows a side view of the second flow tube section of the respiratory flow sensor. [Figure 7] Figure 6 shows a longitudinal cross-sectional view of the second flow pipe section. [Figure 8] Figure 7 shows a detailed cross-section of Y. [Figure 9] Figures 1 to 8 show a perspective view of a breathing adapter equipped with a respiratory flow sensor. [Figure 10] A side view shows the first flow tube section of the respiratory flow sensor according to the second embodiment. [Figure 11] Figure 10 shows a longitudinal cross-sectional view of the first flow pipe section. [Figure 12] A side view shows the second flow tube section of the respiratory flow sensor according to the second embodiment. [Figure 13] Figure 12 shows a longitudinal cross-sectional view of the second flow pipe section. [Figure 14] Detailed cross-sections of Z are shown in Figures 11 and 13. [Figure 15] A longitudinal cross-sectional view shows the first flow tube section of the respiratory flow sensor according to the third embodiment. [Figure 16] A longitudinal cross-sectional view shows the second flow tube section of the respiratory flow sensor according to the third embodiment. [Figure 17] Further embodiments of the respiratory flow sensor according to the present invention are shown in perspective views. [Figure 18] Figure 17 shows a perspective view of the first flow pipe section. [Figure 19] Figure 17 shows a perspective view of the second flow pipe section. [Figure 20] The respiratory flow sensor shown in Figure 10 is further illustrated in a perspective view. [Modes for carrying out the invention]

[0072] In this example, the first embodiment of the respiratory flow sensor 11 shown in Figures 1 to 8 is an injection-molded product, and the respiratory flow sensor 11 is made of plastic.

[0073] As shown in Figures 1 and 2, the respiratory flow sensor 11 has a longitudinal axis 14 and a flow tube 12 having a first flow tube section 21 and a second flow tube section 41, and the regions of the two free ends 16 and 18 have tube connection sections 17 and 19 for artificial respiration tubes, respectively.

[0074] A ventilator tube is positioned on the tube connection 17, which leads to a mouthpiece or ventilator mask (not shown here), and is placed over the patient for artificial respiration. A ventilator tube leading to a ventilator is positioned on the other tube connection 19.

[0075] In the flow tube 12 that forms the flow path 13, a flow resistance 61 is positioned between the first flow tube section 21 and the second flow tube section 41, and this flow resistance is formed as a diaphragm flap. The flow resistance 61 is provided with a circumferential recess 62, which interacts with a cam 30 provided in the first flow tube section 21, thereby ensuring the correct alignment of the flow resistance 61 in the flow path 13 when the respiratory flow sensor 11 is assembled.

[0076] Instead of a protruding cam 30 and a recess 62 interacting with it, precise alignment of the flow resistance 61 in the flow path 13, and furthermore, precise alignment of the first flow tube section 21 and the second flow tube section 41, may be ensured, for example, via adjusting means which may be provided on the outside, and / or via a groove / comb structure.

[0077] The respiratory flow sensor 11 has two connectors 32 and 52 for taking in the pressure difference generated by the flow resistance 61. The openings 35 or 55 of the connectors 32 and 52 are oriented in the same direction, i.e., towards the free end 16 of the first flow tube section 21. The connectors 32 and 52 are provided on the outer jacket surface of the respective flow tube sections 21 and 41, and are adjacent to each other and spaced apart.

[0078] The first flow tube section 21 (see also Figures 3 to 5 in particular) is the first housing portion of the respiratory flow sensor 11. The first flow tube section 21 has an essentially cylindrical section 22 and a radially expanding section 26, resulting in a larger diameter in this region. In the essentially cylindrical section 22, a guide element 23 is provided in its flow path, which divides the flow path 13 into two equal-sized sections in this region, enabling target air guidance within the flow tube 12.

[0079] In the radially expanding portion 26, the corresponding flow path also increases in size toward the open end 24 of the first flow tube portion 21. This open end 24 is provided with a radially projecting flange 27 having a contact surface 29, resulting in a larger diameter in this region. When the respiratory flow sensor 11 is assembled, the contact surface 29 faces the second flow tube portion 41. This flange 27 has a first circumferential portion 28 with a groove / comb structure that is provided on the contact surface 29. In the radially expanding portion 26, within the region of the flange 27, there is a first connecting recess 27a supported by a first support structure 27b. A further connecting portion 52 of the second flow tube portion 41 has a support portion 52a adjacent to the opening 55, which, when assembled, is in close contact with or rests on the first connecting recess 27a of the respiratory flow sensor 11 and is supported by the first support structure 27b.

[0080] The cam 30 protrudes from the contact surface 29 to precisely align the flow resistance 61 in the flow tube 12 when the respiratory flow sensor 11 is assembled.

[0081] A first connection section 32 for taking in the pressure difference caused by the flow resistance 61 is connected to the flow path of the first flow pipe section 21 via a first connection line. The first connection line has a connection line section 33 that extends essentially parallel to the longitudinal axis 14 of the flow pipe 12, and a further connection line section 34 that extends partially linearly and intersects the connection line section 33 that extends essentially parallel to the longitudinal axis 14 of the flow pipe 12 at an angle α of 40° to 70°, preferably 48° to 62°, and particularly preferably 52° to 58°. In this example, this angle α is 55°.

[0082] As an extension of this further connection line portion 34 of the first connection line, the first flow tube portion 21 is provided with a first tool opening 36 for removing a forming tool for forming this further connection line portion 34, and a first closing element 38 for closing the tool opening 36. The first closing element 38 is pivotably mounted on the first flow tube portion 21 via a hinge, in this case via a flexible hinge 39 or a film hinge.

[0083] A groove structure 37 is formed around the first tool opening 36. A comb-shaped structure 40 is formed on the first closing element 38, which engages with the groove structure 37 when the first tool opening 36 is closed, ensuring a seal of the first tool opening 36 and thus a tight seal of the first connection line during the welding process, particularly the ultrasonic welding process.

[0084] In Figure 5, the first tool opening 36 is shown in a closed state.

[0085] The second flow tube section 41 (see also Figures 6-8 in particular) is the second housing portion of the respiratory flow sensor 11. The second flow tube section 41 has an essentially cylindrical section 42 that is tapered on the outside toward the free end 18 and a radially expanded section 46. In the essentially cylindrical section 42, a guide element 43 is provided in its flow path, which divides the flow tube 12 into two equal-sized sections in this region, enabling target air guidance within the flow tube 12. The free end 45 of the guide element 43 is set back relative to the free end 18 of the flow tube 12.

[0086] In the radially expanding portion 46, i.e., outwardly, the corresponding flow channel also increases in size toward the open end 44 of the second flow channel 41. This open end 44 is provided with a radially projecting flange 47 having a contact surface 49, the contact surface 49 facing the first flow channel 21 or its contact surface 29 when the respiratory flow sensor 11 is assembled. The flange 47 is provided with a second circumferential portion 48 of groove / comb structure on the contact surface 49, the second circumferential portion 48 engaging with the first circumferential portion 28 of groove / comb structure and fusing with it during welding, particularly during ultrasonic welding. This easily ensures a sealed connection between the first flow channel 21 and the second flow channel 41. Complex multi-layer structures for groove / comb structures or pressure surfaces, such as those proposed in CH No. 701 755 B1, are unnecessary in the solution according to the present invention.

[0087] The flange 47 is provided with a receiving recess 51 offset from the contact surface 49, which at least partially receives the flow resistance 61. The cylindrical ring of the receiving recess 51 is provided with a hole 50 through which the cam 30 of the first flow tube section 21 passes when assembling the respiratory flow sensor 11. This configuration not only allows for precise alignment of the flow resistance 61 in the flow path 13 when assembling the respiratory flow sensor 11, but also, in combination with the groove / comb-shaped structures 28 and 48 on the flanges 27 and 47, allows for the arrangement of flow resistances of different thicknesses, depending on the application or as needed. Thus, the respiratory flow sensor 11 can be used flexibly and can be adapted to other types of flow resistance 61 without great effort. The flow resistance 61 used is held between the first flow tube section 21 and the second flow tube section 41, and is clamped or otherwise held, in particular by partial or complete bonding.

[0088] In the assembled state of the respiratory flow sensor 11, no flange pressure surfaces are formed on the flanges 27 and 47. The connection between the first flow tube section 21, which serves as the first housing portion of the respiratory flow sensor 11, and the second flow tube section 41, which serves as the second housing portion of the respiratory flow sensor 11, is made solely by simply formed groove / comb-shaped structures 28 and 48 on the flanges 27 and 47.

[0089] The radially extending portion 46 has a further connecting recess 47a in the region of the flange 47, which is supported by a further support structure 47b. The first connecting portion 32 of the first flow tube portion 21 has a support portion 32a adjacent to the first closing element 38, which, in the assembled state, is in close contact with or rests on the further connecting recess 47a of the respiratory flow sensor 11 and is supported by the support structure 47b.

[0090] A second connection section 52 for taking in the pressure difference generated by the flow resistance 61 is connected to the flow path section of the second flow pipe section 41 via a second connection line. The second connection line has a connection line section 53 that extends essentially parallel to the longitudinal axis 14 of the flow path 13, and a further connection line section 54 that extends partially linearly and intersects the connection line section 53 at an angle β of 130° to 160°, preferably 138° to 152°, and particularly preferably 142° to 148°. In this example, this angle β is 145°.

[0091] As an extension of this further connection line portion 54 of the second connection line, a second tool opening 56 for removing a forming tool for forming this further connection line portion 54 and a second closing element 58 for closing the tool opening 56 are provided in the second flow tube portion 41. The second closing element 58 is pivotably mounted in the second flow tube portion 41 via a hinge, here via a flexible hinge 59 or a film hinge.

[0092] A groove structure 57 is formed around the second tool opening 56. A comb-shaped structure 60 is formed on the second closing element 58, which engages with the groove structure 57 when the first tool opening 36 is closed, ensuring a seal of the second tool opening 56 and thus a tight seal of the second connection line during the welding process, particularly the ultrasonic welding process.

[0093] In Figure 8, the second tool opening 56 is shown in an open state.

[0094] To manufacture the respiratory flow sensor 11, the first flow tube section 21 is formed in a manufacturing tool mold, the connecting line section 33 is formed by a pin as a molding tool, and a further connecting line section 34 is formed by a slider as a molding tool. Next, the first flow tube section 21 is released from the manufacturing tool mold, and for this purpose, the slider is pulled out in advance from the first flow tube section 21.

[0095] Simultaneously, or with a time delay, the second flow tube section 41 is formed by a further manufacturing tool mold, the connecting line section 53 is formed by a pin as a molding tool, and the further connecting line section 54 is formed by a slider as a molding tool. Next, the second flow tube section 41 is released from the manufacturing tool mold, and for this purpose, the slider is pulled out in advance from the second flow tube section 41.

[0096] Here, the tool openings 36 and 56 can be closed by the closing elements 38 and 58, respectively.

[0097] The first flow pipe section 21 and the second flow pipe section 41 are aligned with each other, specifically in the axial direction and at an angular position relative to each other.

[0098] Next, in this embodiment, the first flow tube section 21 and the second flow tube section 41 are sealed and connected to each other by ultrasonic welding.

[0099] The breathing adapter 71 shown in Figure 9 comprises a breathing flow sensor 11, a connecting tube 73 that connects the connection portion 32 of the breathing flow sensor 11 to the measuring device 76 to create a first fluid connection from the measuring device 76 to the breathing flow sensor 11, and a connecting tube 74 that connects the connection portion 52 of the breathing flow sensor 11 to the measuring device 76 to create a second fluid connection from the measuring device 76 to the breathing flow sensor 11. The fluid connection is formed directly into one of the flow tubes of the breathing flow sensor 11 so as to be seamless.

[0100] The breathing adapter 71 further comprises a first ventilator tube 77 and a mouthpiece 78 designed as a ventilator mask. The first ventilator tube 77 connects the mouthpiece 78 to the respiratory flow sensor 11. Furthermore, the breathing adapter 71 has a second ventilator tube 79 that connects the respiratory flow sensor 11 to the ventilator 72.

[0101] The measuring device 76 is designed to measure, record, and process the pressure difference generated within the respiratory flow sensor 11. In this example, the measuring device 76 is integrated into a ventilator 72 designed for mechanical ventilation of a patient.

[0102] In a second exemplary embodiment of the respiratory flow sensor shown in Figures 10 to 14, the first flow tube section 81 (see in particular Figures 10 and 11) differs from the first flow tube section 21 of the respiratory flow sensor 11 in essentially only that it is made of several parts and has one connection line. In this case, the connection line section 83 extending from the opening 85 of the connection section 82 is not directly connected to a further connection line section 84. The connection line section 83 and the further connection line section 84 each lead to the open end 86 of the first flow tube section 81. The connection section 82 is further provided on the first flow tube section 81.

[0103] The first flow tube section 81 is designed in two parts, namely flow tube section 91 and flow tube section 93, which are connected to each other by a seal connection. Since the first flow tube section 81 consists of two parts, the structure of the connection line in this first flow tube section can be manufactured in a desired manner while ensuring simple manufacturing. Therefore, no manufacturing opening or tool opening is required to form the first flow tube section 81.

[0104] The configuration of the second flow tube section 101 of the second embodiment of the respiratory flow sensor (see in particular Figures 12 and 13) essentially corresponds to the second flow tube section 41 of the respiratory flow sensor 11. However, in its assembled state, the second flow tube section 101 has an air deflector 112 in the region opposite to the connection section 82 of the first flow tube section 81, and its cavity 113 opens to the free end 114 of the second flow tube section 101.

[0105] As shown in detail in Figure 14, when the first flow section 81 and the second flow section 101 are joined, the path of the first connection line from the connection section 82 into the interior of the first flow section 81 is visible. The fluid is redirected within the cavity 113. The seal connection between the first flow section 81 and the second flow section 101 in this deflection region is provided only at the contact portions 116 and 117. In this embodiment, the first connection line is not formed seamlessly. However, the second connection line of the second flow section 101 is still seamless.

[0106] The first flow tube section 121 (see Figure 15) and the second flow tube section 141 (see Figure 16) of the respiratory flow sensor according to the third embodiment differ only in the design of their connecting lines.

[0107] A first connection section 132 for capturing the pressure difference caused by flow resistance is connected to the flow path of the first flow tube section 121 via a first connection line. A connection line section 133 and a further connection line section 134, extending essentially parallel to the longitudinal axis 124 of the flow tube, intersect at an angle γ of 130° to 160°, preferably 138° to 152°, and particularly preferably 142° to 148°. In this example, this angle γ is approximately 147°. This angle γ was chosen so that a molding tool designed as a slider can be easily withdrawn when the first flow tube section 121 is demolded, without requiring a tool opening for that purpose.

[0108] A second connection section 152 for capturing the pressure difference caused by flow resistance is connected to the flow path of the second flow tube section 141 via a second connection line. A connection line section 153 and a further connection line section 154, extending essentially parallel to the longitudinal axis 124 of the flow tube, intersect at an angle δ of 40° to 70°, preferably 48° to 62°, and particularly preferably 52° to 58°. In this example, this angle δ is 53°. This angle δ was chosen so that a molding tool designed as a slider can be easily withdrawn when the second flow tube section 141 is demolded, without requiring a tool opening for that purpose.

[0109] The first and second connection lines are designed to be seamless.

[0110] In further exemplary embodiments of the respiratory flow sensor 211 shown in Figures 17 to 20, the flow tube 212 has a longitudinal axis 214, a first flow tube section 221, and a second flow tube section 241. Here, the first flow tube section 221 (see in particular Figure 18) is essentially different from the first flow tube section 21 of the respiratory flow sensor 11, in that a first closure element 238 is designed as a tube section 239 in the connection section 232. The first closure element 238 has a first tool opening 236 leading to a further connection line section 234, and a connection line section 233 emerging from the opening 235 of the connection section 232 is directly connected to the further connection line section 234. The first connection section 232 is further provided in the first flow tube section 221.

[0111] The first flow tube section 221 is the first housing portion of the respiratory flow sensor 211. The first flow tube section 221 has an essentially cylindrical section 222 and a radially expanding section 226, resulting in a larger diameter in this region. In the essentially cylindrical section 222, a guide element 223 is provided in its flow path, which divides the flow path 213 in this region into two sections of equal size, enabling targeted air guidance within the flow tube 212.

[0112] In the radially expanding portion 226 of the first flow tube 221, the corresponding flow path also increases in size toward the open end 224 of the first flow tube 221 (see Figure 18 in particular). This open end 224 is provided with a radially projecting flange 227. In the radially expanding portion 226, in the area of ​​the flange 227, there is a first connection recess 227a supported by a first support structure 227b. A further connection portion 252 of the second flow tube 241 has a support portion 252a adjacent to the opening 255, which, in the assembled state, is in close contact with or rests on the first connection recess 227a of the respiratory flow sensor 11.

[0113] The configuration of the second flow tube section 241 in this exemplary embodiment of the respiratory flow sensor 211 (see in particular Figure 19) essentially corresponds to the second flow tube section 41 of the respiratory flow sensor 11. However, this second flow tube section 241 has a closure element 258 designed as a tube section 259 on the second connection section 252. The closure element 258 has a second tool opening 256 leading to a further connection line section 254, and a connection line section 253 emerging from the opening 255 of the second connection section 252 is directly connected to the further connection line section 254. The second connection section 252 is further provided on the second flow tube section 241.

[0114] The second flow tube section 241 is also the second housing portion of the respiratory flow sensor 211. The second flow tube section 241 has an essentially cylindrical portion 242 that tapers outward toward the free end 218. The second flow tube section 241 has a portion 246 that expands radially toward the open end 244. In the essentially cylindrical portion 242, a guide element 243 is provided in its flow path, which divides the flow tube 212 into two equal-sized portions in this region, enabling targeted air guidance within the flow tube 212. The free end 245 of the guide element 243 is set back relative to the free end 218 of the flow tube 212.

[0115] The radially extending portion 246 of the second flow tube section 241 has a further connecting recess 247a in the region of the flange 247, which is supported by a further support structure 247b. The first connecting portion 232 of the first flow tube section 221 has a support portion 232a adjacent to the first closing element 238, which, in the assembled state, is in close contact with or rests on the further connecting recess 247a of the respiratory flow sensor 11.

[0116] Figure 20 shows the assembled respiratory flow sensor 211, with the tool openings 236 and 256 on the tubular sections 239 and 259 shown closed. These were hermetically sealed using an ultrasonic welding apparatus in an ultrasonic welding process.

[0117] <Note> [1] A respiratory flow sensor, A flow tube (12;212) having longitudinal axes (14;124;214), a first flow tube section (21;81;121;221), and a second flow tube section (41;101;141;241), A flow resistance (61) is positioned between the first flow section (21;81;121;221) and the second flow section (41;101;141;241) within the flow pipe (12;212), Connections (32, 52; 82, 102; 132, 152; 232, 252) for taking in the pressure difference generated by the flow resistance (61), It has, The first connection section (32;82;132;232) is connected to the first flow pipe section (21;81;121;221) via the first connection line. Further connections (52;102;152;252) lead to the second flow pipe section (41;101;141;241) via a second connection line. Each of the connecting sections (32, 52; 232, 252) has a connecting line section (33, 53; 83; 133, 153; 233; 253) that extends essentially parallel to the longitudinal axis (14; 124; 214) of the flow pipe (12; 212). The openings (35, 55, 85, 235, 255) of the connecting parts (32, 52; 82, 102; 132, 152; 232, 252) are oriented in the same direction. In respiratory flow monitoring, The first connection section (32;82;132;232) is provided in the first flow pipe section (21;81;121;221), Further connection points (52;102;152;252) are provided in the second flow pipe section (41;101;141;241). A respiratory flow sensor characterized by the above. [2] The aforementioned connection lines are, The respiratory flow sensor according to item [1] above, characterized in that it has a further connecting line portion (34, 54, 84, 134, 154, 234, 254) that intersects at a predetermined angle (α, β, γ, δ) with the connecting line portion (33, 53, 83, 133, 153, 233, 253) which extends at least partially in a linear manner and is essentially parallel to the longitudinal axis (14, 124, 214) of the flow tube (12, 212). [3] The respiratory flow sensor according to item [2] above, wherein one of the connection lines, the further connection line portion (34;154;234;254) extending at least partially in a linear manner, intersects the connection line portion (33;153;233;253) of the connection line, which extends essentially parallel to the longitudinal axis (14;124;214) of the flow tube (12;212), at an angle (α) of 40° to 70°, preferably 48° to 62°, and particularly preferably 52° to 58°. [4] The respiratory flow sensor according to [2] or [3], wherein the further connecting line portion (54;134;234;254) of the other connecting line, which extends at least partially in a linear manner, intersects the connecting line portion (53;133;233;253) of the other connecting line, which extends essentially parallel to the longitudinal axis (14;124;214) of the flow tube (12;212), at an angle (β) of 130° to 160°, preferably 138° to 152°, and particularly preferably 142° to 148°. [5] The first connection portion (32;82;132;232) is arranged adjacent to the further connection portion (52;102;152;252), Preferably, the respiratory flow sensor according to any one of the above [1] to [4], characterized in that the first connection portion (32;82;132;232) is also positioned at a distance from the further connection portion (52;102;152;252). [6] The first connecting portion (32;82;132;232) is at least partially provided on the outer jacket surface of the first flow tube portion (21;81;121;221), and / or, The respiratory flow sensor according to any one of the above [1] to [5], characterized in that the further connecting portions (52;102;152;252) are at least partially provided on the jacket surface of the second flow tube portion (41;101;141;241). [7] The first flow tube section (21;81;121;221) and / or the second flow tube section (41;101;141;241) have essentially cylindrical portions (22, 42;222, 242) and radially expanding portions (26;226;46, 246), The radially expanding portions (26;226;226;46, 246) extend toward the open ends (24, 224;44, 244) of each of the first flow tube sections (21;81;121;221) or the second flow tube sections (41;101;141;241). In particular, the respiratory flow sensor according to any one of the above [1] to [6], characterized in that radially projecting flanges (27, 47, 227, 247) having contact surfaces are provided at the open ends (24, 224, 44, 244) of the first flow tube section (21; 81; 121; 221; 221) and the second flow tube section (41; 101; 141; 241), respectively. [8] On the radially extending portion (26;226) of the first flow tube section (21;81;121;221), there are first connecting recesses (27a;227a) for at least partially receiving the further connecting portions (52;102;152;252) of the second flow tube section (41;101;141;241). and / or, The respiratory flow sensor according to [7], characterized in that there are further connecting recesses (47a; 247a) on the radially expanding portion (46; 246) of the second flow tube portion for at least partially receiving the first connecting portion (32; 82; 132; 232) of the first flow tube portion (21; 81; 121; 221). [9] A tool opening (36, 56; 236, 256) is provided for removing a forming tool for forming further connecting line portions (34, 54; 234, 254) of the connecting line, and a closing element (38, 58; 238, 258) is provided for closing this tool opening (36, 56; 236, 256). A first closing element (38;238) for closing a further connecting line portion (34;234) of the first connecting line is preferably provided in the first flow pipe portion (21;221). A respiratory flow sensor according to any one of the above [2] to [5], characterized in that a second closing element (58;258) for closing a further connecting line portion (54;254) of the second connecting line is preferably provided in the second flow tube portion (41;241).

[10] The first closing element (38) is pivotably mounted on the first flow tube section (21) via a hinge, preferably via a flexible hinge (39). and / or, The respiratory flow sensor according to [9] above, characterized in that the second closing element (58) is rotatably mounted on the second flow tube (41) via a hinge, preferably via a flexible hinge (59).

[11] A groove / comb structure (37, 40, 57, 60) is provided on the tool opening (36, 56; 236, 256) and / or the closing element (38, 58; 238, 258), Preferably, the closing elements (38, 58; 238, 258) are fixed to the respective flow tube sections (21, 41; 221, 241) by sealing connections, particularly preferably by ultrasonic welding, to close the tool openings (36, 56; 236, 256), the respiratory flow sensor according to [9] or

[10] above.

[12] A breathing adapter having at least one respiratory flow sensor (11) as described in any one of the above items [1] to

[11] , and at least one connecting tube (73, 74) which connects one of the connection parts (32, 52; 232, 252) of the respiratory flow sensor (11) to a measuring device (76) to create a fluid connection from the measuring device (76) to the respiratory flow sensor (11), The respiratory adapter is characterized in that the fluid connection is formed seamlessly and directly into one of the flow tube sections (21; 81; 121; 221) of the respiratory flow sensor (11).

[13] At least one ventilator tube (77, 79) and mouthpiece (78) are provided. The respiratory adapter according to

[12] above, characterized in that at least one ventilator tube (77) has a mouthpiece (78) connected to at least one respiratory flow sensor (11).

[14] A method for manufacturing a respiratory flow sensor (11) according to any one of the above items [1] to

[11] , a) The first flow tube section (21;81;121;221) and the second flow tube section (41;101;141;241) are formed using a manufacturing tool mold, and the corresponding connecting line sections (33 or 53;83;133 or 153;233 or 253) and further connecting line sections (34 or 54;84;134 or 154;234 or 254) are formed by a slider as a forming tool and / or by a pin as a forming tool; b) The step of releasing the first flow tube section (21;81;121;221) and the second flow tube section (41;101;141;241) from their respective manufacturing tool molds, c) The step of aligning the first flow pipe section (21;81;121;221) and the second flow pipe section (41;101;141;221) with respect to each other in terms of axial and angular position, d) The step of forming a seal connection between the first flow pipe section (21;81;121;221) and the second flow pipe section (41;101;141;241), A method characterized by having the following: [Explanation of Symbols]

[0118] 11 Respiratory flow sensor, 12 Flow tube, 13 Flow path, 14 Longitudinal axis of 12, 16 Free end of 12, 17 Tube connection, 18 Free end of 12, 19 Tube connection, 21 First flow tube section, 22 Cylindrical section, 23 Guide element, 24 Open end of 21, 26 Expanding section, 27 Flange, 27a First connection recess, 27b First support structure, 28 First circumferential section of groove / comb structure, 29 Contact surface, 30 Cam, 32 First connection section, 32a Support section of 32, 33 Connection line section, 34 Connection line section, 35 Opening of 32, 36 First tool opening, 37 Groove structure, 38 First closing element, 39 Flexible hinge, 40 Comb structure, 41 Second flow tube section, 42 Cylindrical section, 43 Guide element, 44 Open end of 21, 45 Free end of 43, 46 Enlarged portion, 47 Flange, 47a Further connection recess, 47b Further support structure, 48 Second circumferential portion of groove / comb structure, 49 Contact surface, 50 Hole, 51 Receiving recess, 52 Second connection portion, 52a Support portion of 52, 53 Connection line portion, 54 Further connection line portion, 55 Opening of 32, 56 Second tool opening, 57 Groove structure, 58 Second closing element, 59 Flexible hinge, 60 Comb structure, 61 Flow resistance, 62 Recess of 61, α Angle between 33 and 34, β Angle between 53 and 54, 71 Breathing adapter, 72 Ventilator, 73 First connection tube, 74 Second connection tube, 76 Measuring device / ventilator, 77 First breathing tube, 78 Mouthpiece, 79 Second ventilator tube, 81 First flow tube section, 82 First connection section, 83 Connection line section, 84 Further connection line section, 85 Opening of 82, 86 Open end of 81, 91 First flow tube section, 93 Second flow tube section, 101 Second flow tube section, 102 Second connection section, 112 Air deflector, 113 Cavity of 112, 114 Free end of 101, 116 Contact section, 117 Contact section, 121 First flow tube section, 124 Longitudinal axis, 132 First connection section, 133 Connection line section, 134 Further connection line section, 141 Second flow tube section, 152 Second connection section, 153 Connection line section, 154 Further connection line section, 211 Respiratory flow sensor, 212 Flow tube, 213 Flow path, 214 Longitudinal axis, 218, free end of 212, 221 first flow tube section, 222 cylindrical section, 223Guide element, 224 Open end of 221, 226 Spreading portion, 227 Flange, 227a First connection recess, 227b First support structure, 232 First connection, 232a Support portion of 232, 233 Connection line portion, 234 Further connection line portion, 235 Opening, 236 First tool opening, 238 First closing element, 239 Pipe portion, 241 Second flow pipe portion, 242 Cylindrical portion, 243 Guide element, 244 Open end, 245 Free end of 243, 246 Spreading portion, 247 Flange, 247a Further connection recess, 247b Further support structure, 252 Second connection, 252a Support portion of 252, 253 Connection line portion, 254 Further connection line portion, 255 Opening, 256 Second tool opening, 258 Closure element, 259 tubular section, γ angle between 133 and 134, δ angle between 153 and 154.

Claims

1. A flow tube having a longitudinal axis, including a first flow tube section and a second flow tube section, A flow resistance is provided within the flow pipe, between the first flow pipe section and the second flow pipe section. A first connection and a second connection for taking in the pressure difference generated by the flow resistance, Equipped with, The first connection portion is connected to the first flow pipe portion through the first connection line, The second connection section is connected to the second flow pipe section through the second connection line, The first connection line and the second connection line each include a tool opening and a closing element configured to fit into the tool opening. Respiratory flow sensor.

2. The respiratory flow sensor according to claim 1, wherein the first flow tube and the second flow tube are designed to be molded in a manufacturing tool mold, and the tool opening is configured to be releaseable from a molding tool used to mold a corresponding connection line.

3. The breathing flow sensor according to claim 2, wherein the molding tool comprises a slider and / or a pin.

4. The respiratory flow sensor according to claim 1, wherein the closing element has a plug.

5. The respiratory flow sensor according to claim 4, wherein the closing element is positioned in the tool opening so as to be rotatable on a hinge.

6. The respiratory flow sensor according to claim 5, wherein the hinge is a living hinge or a film hinge.

7. The respiratory flow sensor according to claim 1, wherein the tool opening has a groove structure, and the closing element has a comb-shaped structure configured to engage with the groove structure to close the tool opening.

8. The respiratory flow sensor according to claim 1, wherein the closing element is configured to close the tool opening by a tight fit, bond, or weld.

9. The respiratory flow sensor according to claim 1, wherein the closing element is configured to close the tool opening by ultrasonic welding.

10. The respiratory flow sensor according to claim 1, wherein the first flow tube and the second flow tube include a seal connection that connects both the first flow tube and the second flow tube in axial and angular positions.

11. The respiratory flow sensor according to claim 10, wherein the seal connection has a welded connection or an adhesive connection.

12. The respiratory flow sensor according to claim 10, wherein the seal connection has an ultrasonic welding connection.

13. The first flow tube section has a first radially projecting flange, a first circumferential groove / comb-shaped structure, and a first contact surface. The second flow tube section has a second radially projecting flange, a second circumferential groove / comb-shaped structure, and a second contact surface. The respiratory flow sensor according to claim 10, wherein the seal connection has a first circumferential groove / comb structure and a second circumferential groove / comb structure that enable the first flow tube portion and the second flow tube portion to connect to the first contact surface and the second contact surface.

14. The first flow tube portion includes the first connecting portion on its outer surface and has a first essentially cylindrical portion and a portion that gradually widens radially, ending at the first contact surface. The second flow tube portion includes the second connection portion on its outer surface: It has a second essentially cylindrical portion and a radially extending portion ending at the second contact surface, The second essentially cylindrical portion has a larger radius than the first essentially cylindrical portion of the first flow tube. The respiratory flow sensor according to claim 13, wherein the radially extending portion has a larger radius than the second essentially cylindrical portion.

15. The respiratory flow sensor according to claim 14, wherein the first essentially cylindrical portion and the second essentially cylindrical portion each include a guide element that divides each flow tube into two portions of the same size.

16. The respiratory flow sensor according to claim 14, wherein the first connection portion and the second connection portion each include an opening, and the openings of the first connection portion and the second connection portion are oriented in the same direction.

17. The first connection line includes a first portion extending essentially parallel to the longitudinal axis of the flow pipe, and a first further connection line portion extending at least partially linearly and intersecting the first portion extending essentially parallel to the longitudinal axis at a first angle α, The respiratory flow sensor according to claim 1, wherein the second connection line includes a second portion extending essentially parallel to the longitudinal axis of the flow tube, and a second further connection line portion extending at least partially and intersecting the second portion extending essentially parallel to the longitudinal axis at a second angle β.

18. The respiratory flow sensor according to claim 17, wherein the first angle α is acute and the second angle β is obtuse.

19. The respiratory flow sensor according to claim 18, wherein the first angle α is between 40° and 70°.

20. The respiratory flow sensor according to claim 18, wherein the second angle β is between 130° and 160°.

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