CH701755A1 - Flow rate measuring detector for determining air flow of patient, has channel with channel opening and another channel opening, where channel defines cylindrical housing - Google Patents

Abstract

The flow rate measuring detector has a channel with a channel opening (13) and another channel opening (29), where the channel defines a cylindrical housing. A flow resistance (23) is arranged in the channel of the housing. The supply connections (17,19) are arranged in a distance from each other on the identical housing parts (11,27).

Description

Field of the invention

The invention relates to a flow sensor according to the preamble of claim 1. The flow sensor is used to determine the breathing air flow of a patient. When flowing through the flow sensor, the pressure difference on opposite sides of a flow resistance is measured via connected sensor tubes and a pressure gauge. The measurements obtained are used to determine the respiratory air flow and allow the observation of a patient about his breathing and / or the control of a ventilator.

State of the art

Flow measurement guide and from the patent US 4 083 245 known. The content of this patent is incorporated by reference in the present application. This flow sensor is characterized by a cylindrical housing with a passage for the breathing air, a arranged in the passage of the housing flow resistance and connection points for sensor hoses on both sides of the flow resistance. The sensor hoses are led out of the cylindrical housing perpendicular to the flow direction. The cylindrical housing is usually constructed of two identical parts. Such housing parts are thus relatively easy and inexpensive to manufacture.

A major disadvantage of known flow sensor is the Abknickgefahr the sensor tubes. The kinking results in erroneous measurement results and thus incorrect patient status information. A control of a ventilator based on erroneous measurement results can result in medical complications for the patient.

Another disadvantage of known flow sensor results from the merger of the probe with flexible hose parts of the respirator. Since the position of these moving parts can influence the measurement results, they are subject to an increased measurement error. This, in turn, complicates the control of a ventilator and can lead to complications for the patient. Another disadvantage is that the two housing parts are identical. As a result, an individual adaptation to patient-side and / or device-side air supply tubes is possible only via special adapter parts. Such additional parts increase the risk of mishandling and the dead volume.

Object of the invention

The object of the invention is to eliminate the disadvantages presented above and to produce an improved flow sensor.

description

According to the invention the object is achieved in a flow sensor according to the preamble of claim 1, characterized in that the first and second connection point for sensor tubes are arranged at a distance from each other on the same housing part. This makes it possible to direct the outgoing sensor hoses against the side of the device, whereby they can be performed directly to the pressure gauge. Advantageously, the sensor tubes are led away parallel to and with the device-side air supply tube. In use, no sensor tubes are directed against the patient. The patient side is free of troublesome tubing and the risk of kinking the tubing in use is reduced. Ventilation is thus safer and less complicated for the patient and the nursing staff.

Advantageously, the first connection point as the first connecting piece and the second connection point as a second connecting piece for the connection of a connecting line to at least one pressure sensor is formed. This ensures a robust connection between the sensor hose and the flow sensor. A buckling directly at the junction is also prevented.

In an advantageous embodiment, the connecting pieces are aligned substantially parallel to the longitudinal axis of the cylindrical housing. This allows the sensor tubes to be routed in parallel with the air supply tube in the direction of the ventilator and pressure gauge.

Advantageously, the housing is in two parts, wherein flanges are formed on the first housing part and on the second housing part for connecting the housing parts. This two-part construction is advantageous in the manufacture of the parts. For example, it is possible to design the housing parts in an application-specific manner, ie. Connection currents and larger can be selected and combined according to customer requirements. Conveniently, both housing parts may have the same or different shape and / or size on the opposite ends. Through holes (13, 29) with connection are adaptable to the shape and diameter of the connected air supply tubes. The housing parts are fixed by gluing, in particular ultrasonic gluing, pressing or welding of the flange surfaces (also called flange pressure surfaces).

In an advantageous embodiment, means for mutual relative alignment of the housing parts are provided on the flanges. These means are conveniently applied to the surfaces, i. Pressure surfaces, the flanges attached. The presence of such means simplifies the assembly of flow sensors and ensures mutually correct positioning. Only with correct positioning of the housing parts is an open connection between connection points and respective chambers in the housing interior guaranteed.

In an advantageous embodiment, means for cohesive connection formation are provided on the flanges. The cohesive connection is expediently impermeable to air, so that ventilation and pressure measurement are not impaired by leaks.

The means for cohesive connection formation advantageously consist of profile structures, in particular ultrasonic welding profiles. These agents can be processed by welding, pressing or gluing to cohesive connections. Preferably, ultrasonic bonding is used for the material connection of these profiles.

Advantageously, profile structures - consisting of elevations - and groove structures - consisting of wells - arranged to receive material on the pressure surfaces of the first flange and the second flange complementary to each other, so that a maximum material bond when connecting the two flange surface is achieved.

Advantageously, leads from the first connection point, a first connection to a first opening in the interior of the first housing part and from the second connection point, a second connection to a second opening in the interior of the second housing part. These connections pass through the housing wall. Construction and material should be so combined and designed that such a connection is possible, i. the wall thicknesses should be high enough and the material should have a certain strength. The material used is advantageously made of plastic, in particular a thermoplastic, which is physiologically harmless and preferably transparent. Conveniently, the flow sensor is designed so that the openings in the interior of the housing parts and the origin of the movable flap of the flow resistance during their use at the top, ie higher side, so that liquid and mucus can flow down the underside without getting into the sensor tubes or affecting the function of the flap.

Advantageously, the connections partially extend in the flange surfaces and / or exit as openings through the flange surfaces. The connections may lie in sections in only one flange surface. This has the following advantages: A peripheral arrangement of the connection points on a flange extension is possible, which also results in a free choice of position and connection angle of the sensor tubes on the flange extension.

Advantageously, the connections are partially formed as slots in the flange surfaces and partly as channels through the housing parts. The combination of channels and slots simplifies the manufacture of the parts, for example by injection molding. Because slots and / or channels are structurally possibly necessary only on a flange. As a result, the counterpart can possibly be made structurally simpler.

Advantageously, openings opening onto the flange surfaces are formed by continuous surface structures, e.g. Elevation structures or groove structures, edged. As a result, in the assembled flowmeter sensor, a disturbing influence which distorts the measurement results is prevented by leaks.

Advantageously, openings on the first flange surface, which form a connection to the interior of the first housing part, are jointly enclosed by a continuous structure, and openings on the second flange surface, which connect to the interior of the second housing part, together by a second uninterrupted Framed structure; and the passage opening of the cylindrical housing are enclosed by another continuous structure, these structures having opening groups, i. the said common edged openings, delimit each other. As a result, in the assembled flowmeter sensor, an interfering influence that distorts the measurement results is prevented by leaks between the various connection paths.

Advantageously, the openings in the interior of the housing parts in each case the same distance to the flow resistance are arranged opposite one another. This increases the measurement accuracy of the pressure difference.

Advantageously, both connections to the interior of the housing parts of equal length. This also increases the measurement accuracy of the pressure difference.

Advantageously, means for arranging the flow resistance are provided on the flange surfaces. These may be pins, for example, which interact with recesses on the flow resistance.

Advantageously, the flanges have a diameter which is larger than the housing diameter. As a result, a peripheral arrangement of the connection points is possible, which also follows a free choice of position and connection angle of the sensor tubes.

Advantageously, the passage of the housing in the central part has an area of increased diameter, wherein the flow resistance is arranged within this area and divides the passage into two chambers. This is particularly advantageous for ventilation. Because this prevents that draining liquid and mucus affect the measurement noticeably. The movable flap can be constructed so large that, if it breaks off, it remains in the flow sensor and thus can not enter the respiratory tract of the patient.

According to the invention, the object of the invention is alternatively achieved in a flow sensor according to the preamble of claim 22, characterized in that a guide element is arranged in the interior of the second housing part. This makes it possible to influence the air flow so that the flow flows through the sensor substantially uninfluenced by the position and bending of the length of hose lying in front of the opening (29). It is believed that the existing flow vortex or transverse flow components are reduced and the laminar flow rate through the guide element is increased. This makes it possible to measure a differential pressure which is independent of the position and bending of the upstream of the opening (29) hose piece. The measurement of the ventilation values and thus the ventilation control of a patient is thereby improved. The susceptibility to artificial respiration is thus reduced. In addition, the guide allows flow correction over a short distance. Since flow inhomogeneity has always been a problem, especially with short tube systems, the present embodiment additionally offers the advantage that the length of a tube system between the flow sensor and the lungs can be reduced without having to accept a deterioration of the measurement results. This in turn allows for a reduction in the dead volume. This is of particular importance to small patients with low lung volumes, such as children and neonates.

In one embodiment, such a guide element is arranged in the flow sensor according to claim 1 in the interior of the second housing part. This leads to the same advantages mentioned in the previous paragraph.

In one embodiment, the guide element consists of several interacting parts. As a result, flow conditions can be adapted to the respective situation.

Advantageously, the guide element extends in the flow direction in the housing passage and thereby divides the passage of the housing in passage chambers, so that the solder element has a plane of symmetry, which is spanned by the axis of the passage opening and the center of the opening. As a result of this arrangement of the guide element, which is symmetrical with respect to the opening, an air flow which is symmetrical to the opening is obtained equally. This results in better reproducible measurement results.

In a preferred embodiment, the guide element is formed as a small plate, which divides the passage of the housing part in sections into two mirror-image contiguous through chambers, which lie in their extension to the left and right of the openings. From an industrial point of view, it is interesting that a high degree of position insensitivity of the measurement results is achieved by a simple platelet shape of the guide element alone.

In a further preferred embodiment, the guide element is spaced in the direction of the passage opening from the inner housing to allow insertion of a piece of tubing. Such connectors are easy to handle in practice. There is no need for a further adapter: the breathing tube and the flowmeter are directly connected. The length of the tube system between Drurchflussmessfühler and lung can be further reduced, which in turn has a reduction in the dead volume and thus is particularly advantageous for small patients with low lung volume.

In a preferred use of the flow sensor according to claim 1 or claim 22, the first housing part is connected to the device side and the second housing part on the patient side. This has the following advantages: On the one hand in connection with the device according to claim 1, the measuring hoses leading to the differential pressure measuring device can be led away from the patient directly and parallel to one another. The risk of kinking this is reduced. The comfort for patient and nursing staff increased. For changing in connection with the device according to claim 22, the air flow of the exhaled air is aligned by a guide element. In this way, first, a movement-related positional influence on the differential pressure measurement results is reduced or eliminated. Secondly, it is possible to use a shorter tube system on the respiratory or patient side. This in turn results in a lower dead volume.

In summary, it can be emphasized that the two variants of the invention according to claim 1 and claim 22 and in particular their combination solve known problems, bring the location and length of the hose system with it,

The invention will be described in more detail below with reference to the figures in schematic representation. It shows: <Tb> FIG. 1: <sep> Perspective view of a flow sensor in three parts; <Tb> FIG. 2: <sep> longitudinal section through the composite flow sensor; <Tb> FIG. 3: <sep> Device-side housing part in perspective view; <Tb> FIG. 4a: <sep> front view and top view of the device-side housing part; <Tb> FIG. 4b <sep> Longitudinal section of the device-side housing part; <Tb> FIG. 5: <sep> Patient-side housing part in perspective view; <Tb> FIG. 6a <sep> front view and top view of the patient-side housing part; <Tb> FIG. 6b: <sep> longitudinal sections of the patient-side housing part of Fig. 6a; <Tb> FIG. 7: <sep> Patient-side housing part in perspective view with guide element <Tb> FIG. 8a: <sep> front view and top view of the patient-side housing part with guide element; <Tb> FIG. 8b: <sep> longitudinal sections of the patient-side housing part of FIG. 8a; <Tb> FIG. 9: <sep> Longitudinal section through the composite flow sensor with guide element;

Fig. 1 shows a perspective view of a flow sensor in three parts: a first housing part (11) a flow resistance (23) and a second housing part (27). The first housing part (11) has a passage opening (13) with connection to the device-side air supply tube (not shown), a first flange (15) with a flange extension (16), two connection points (17, 19) each with a connecting piece (18, 20) and a first connection channel (21) from the sealing surface of the first flange (15) to the interior of the first housing part (11). The flow resistance (23) consists of a thin membrane, which is cut in such a way that a movable central flap (25) is formed. The second housing part (27) has a through-opening (29) with connection to the patient-side air supply tube (not shown), a second flange (31) with a flange extension (32), a second connecting channel (33) (only the sealing surface-side opening can be seen here) from the sealing surface of the second flange (31) to the interior of the second housing part (27). At the flange extension (32) of the second housing part (27) are two slots (first slot (35) and second slot (37)) - as shown below - the connection of the connection points (first connection point (17) and second connection point ( 19)) to the connecting channels (first connecting channel (21) and second connecting channel (33)) and thus allow the interior of the housing parts. Furthermore, on the opposing flange surfaces (first flange surface (15) and second flange surface (31)) pins 41 (see Fig. 4b) and mating recesses (39) are formed, both the positioning of the flow resistance with respect to the housing parts as Also ensure the mutual positioning of the two housing parts.

Fig. 2 shows the cohesive arrangement of the first housing part (11), the second housing part (27) and intermediate flow resistance (23). For cohesive arrangement, an ultrasonic welding connection (43) is used, which is airtight after welding the housing parts.

In Fig. 3, the first housing part is shown in a further perspective view. Here, the non-central arrangement of the sealing surface side opening of the first connection channel (21) between the connection points (17) and (19) is illustrated. In Fig. 4a is further seen that the connecting channel (21) leads to the interior of the first housing part (11). The inside opening (12) in this case lies centrally below the first flange extension (16).

As can be seen in FIGS. 4 a and 4 b, continuous welding structures (45) are formed as elevations, along the outer edge of the sealing surfaces of the first flange (15) and its extension (16). In addition, the seal-side openings of the connection points (17, 19) and the connection channel (21) with the welding structure (45) are enclosed so that on the one hand, the seal-side opening of the second connection point (19) is bordered with the welding structure and separated from the other both seal-side openings of the first connection point (17) and of the first connection channel (21) with the welding structure (45) are enclosed. In addition, positioning pins (41) can be seen in FIGS. 4a and 4b. These are arranged on the flange pressure surface on a circle around the center of the housing passage.

In Fig. 5, the second housing part is shown in a further perspective view. The non-central arrangement of the second connection channel (33) with respect to the flange extension (32) can be seen. In Fig. 6a is further seen that the connecting channel (33) leads to the interior of the second housing part (27). The inside opening (28) in this case lies centrally below the second flange extension (32).

As can be seen in FIGS. 6a, 6b and 6c, continuous groove structures (47) run along the outer edge of the sealing surfaces of the second flange (31) and its extension (32). In addition, the seal-side openings of the slots (35, 37) and the connection channel (33) are bordered with the groove structure (47) so that on the one hand, the seal-side opening of the first slot (35) is bordered with the groove structure and separated from the other both seal-side openings of the second slot (37) and the second connection channel (33) with the groove structure (47) are bordered. Furthermore, positioning recesses (39) can be seen in FIGS. 6a and 6c. These are arranged on the flange pressure surface on a circle around the center of the housing passage.

In the embodiment shown here, the flow resistance (23, Fig. 1) with its recesses (49) and the second housing part (27) with its recesses (39) on the pins 41 (Fig. 4a) of the first housing part (11 ). As a result, the first housing part (11) and the second housing part (27) are positioned and fitted to one another as well as being materially and airtightly connected to one another. In this cohesive arrangement, the first connection point (17), the first slot (35) and the first connection channel (21) .so connected, that a gas pressure exchange between the interior of the first housing part (11) and a pressure sensor hose at the first connection point (17) is connected is possible. In addition, the second connection point (19), the second slot (37) and the second connection channel (33) are connected so that a gas pressure exchange between the interior of the second housing part (27) and a sensor tube at the second connection point (19) connected, is possible. By means of a pressure sensor it is possible, with this arrangement, continuously or from time to time a pressure difference between the interiors of the first and second housing parts, i. on both sides of the flow resistance. The obtained measurements can be used to observe a patient and / or control a ventilator.

In a further embodiment, a guide element (51) is arranged in the interior of the second housing part (27). The guide element shown in FIGS. 7, 8a, 8b and 9 is designed as a plate. This plate acts as a flow straightener and is aligned in the flow direction in the interior of the second housing part (27). As shown in FIGS. 8a and 8b, the housing passage is divided by the guide element (51) in sections into two chambers (53, 55). The guide element is arranged between the connection opening (29) and the second opening (28) in the interior of the second housing part. As seen in Figure 8a, the wafer is aligned on the plane formed by the axis (57) of the through-hole (29) and the center (59) of the orifice (28). The guide element (53) is connected at two of its opposite edges via lugs with the cylindrical housing wall (Fig. 8b). Towards the connection opening, the guide element is designed as a free-standing nose. As shown in Fig. 8b, the baffle in the passage direction from the second opening (28) in the interior of the second housing part is approximately the diameter of that opening (28). spaced. In Fig. 9 is a section through the entire Durchflüssmessfühler shown. The guide element (51) is integrated in the second, patient-side housing part (28), while the two connecting pieces (18 (not shown) and 20) on the first, device-side housing part (11) spring from the flange extension.

Such a guide can also be integrated in commercial flow sensors. For example, such a guide element can be integrated as a variant in the known flow sensor according to patent document US4083245 (in particular according to Fig. 1 and the claims 1-5).

Legend:

[0042] <tb> 10 <sep> Cylindrical housing <tb> 11 <sep> First case <tb> 12 <sep> First opening inside the first case <tb> 13 <sep> Connection opening to the device-side air supply tube <tb> 15 <sep> First flange, with first flange surface <tb> 16 <sep> First flange extension, with first flange extension surface <tb> 17 <sep> First connection point <tb> 18 <sep> First connection piece <tb> 19 <sep> Second connection point <tb> 20 <sep> Second connection piece <tb> 21 <sep> First connection channel <Tb> 23 <sep> flow resistance <Tb> 25 <sep> flap <tb> 27 <sep> Second housing part <tb> 28 <sep> Second opening in the interior of the second housing part <tb> 29 <sep> Connection opening to the patient-side air supply tube <tb> 31 <sep> Second flange, with second flange surface <tb> 32 <sep> Second flange extension, with second flange extension surface <tb> 33 <sep> Second connection channel <tb> 35 <sep> First slot <tb> 37 <sep> Second slot <Tb> 39 <sep> .Ausnehmungen <Tb> 41 <sep> Writing <tb> 43 <sep> Ultrasonic welding connection (here a superposition of original weld profile elevation and original groove) <Tb> 45 <sep> Ultrasonic welding profile <Tb> 47 <sep> groove structure <Tb> 49 <sep> recesses <Tb> 51 <sep> vane <tb> 53 <sep> First passage chamber <tb> 55 <sep> Second passage chamber <tb> 57 <sep> axis of the through hole (29) <tb> 59 <sep> Center of the opening (28)

Claims (27)

1. Flow sensor (10) with a passage defining a cylindrical housing (10) having a first passage opening (13) and a second passage opening (29), a flow resistance (23) arranged in the passage of the housing, which divides the housing into a first and a second housing part (11 and 27), a first connection point (17) with a connection to the interior of the first housing part (11), and a second connection point (19) with a connection to the interior of the second housing part, characterized in that the first and second connection points (17, 19) are arranged at a distance from one another on the same housing part. 2. flow sensor according to claim 1 wherein the first connection point (17) as a first connecting piece (18) and the second connection point (19) as a second connecting piece (20) for connecting a connecting line to at least one pressure sensor is formed. 3. flow sensor according to claim 2 wherein the connecting pieces (18, 20) are aligned substantially parallel to the longitudinal axis of the cylindrical housing (10). 4. flow sensor according to one of the preceding claims wherein the housing is in two parts, wherein on the first housing part (11) and the second housing part (27) for connecting the housing parts flanges with flange surfaces (15, 16, 31, 32) are formed. 5. flow sensor according to claim 4 wherein means for mutual relative alignment of the housing parts (11, 27) are provided on the flanges. 6. Flow sensor according to one of claims 4 to 5 wherein on the flange surfaces (15, 31) means are provided for cohesive connection formation. 7. flow sensor according to claim 6 wherein the cohesive compound formation on a weld, in particular a Ultraschallverschweissung based. 8. flow sensor according to one of claims 6 to 7 wherein the means for cohesive connection formation consist of groove and welding structure. 9. flow sensor according to claim 8 wherein groove and welding structure on the surfaces of the first flange (15, 16) and the second flange (31, 32) are mutually complementarily arranged. 10. flow sensor according to one of claims 4 to 9 wherein the compounds extend partially in the flange and / or exit as openings through the flange. 11. flow sensor according to claim 10 wherein the compounds partially as slots (35, 37) in the flange surfaces and partly as channels (21, 33) through the housing parts (11, 27) are formed. 12. flow sensor according to one of claims 10 to 11 wherein openings (17, 19, 21, 33, 35, 37) which open onto the flange surfaces, by continuous groove structures (47) or profile elevation structures (45) are enclosed. 13. Flow sensor according to one of claims 10 to 12 wherein openings (17, 21) on the first flange pressure surface, which form a connection to the interior of the first housing part, are jointly enclosed by a continuous structure, and wherein openings (33, 37) on the second flange pressure surface, which form a connection to the interior of the second housing part, are jointly enclosed by a second uninterrupted structure; and wherein the passage opening of the cylindrical housing is bordered by a further continuous structures, and these structures, said opening groups delimit each other and either groove structures (47) or welding structures (45). 14. Flow sensor according to one of claims 4 to 13 wherein on the flange surfaces (15, 31) means for arranging the flow resistance (23) are provided. 15. Flow sensor according to one of claims 4 to 14 wherein the flanges have a diameter which is greater than the housing diameter. 16. flow sensor according to one of the preceding claims wherein the two housing parts (11, 27) on the opposite ends have different shape and / or size. 17. Flow sensor according to one of the preceding claims, wherein from the first connection point (17) a first connection to a first opening (12) in the interior of the first housing part (11) and from the second connection point (19) a second connection to a second opening ( 28) in the interior of the second housing part (27) leads. 18. Flow sensor according to any one of the preceding claims wherein the openings (12, 28) in the interior of the housing parts (11, 27) in each case the same distance from the flow resistance (23) are arranged opposite one another. 19. flow sensor according to any preceding claim wherein the connections to the interior of the respective housing parts have the same length. 20. flow sensor according to one of the preceding claims wherein the passage of the housing in the central part has an area with an enlarged diameter, wherein the flow resistance (23) is arranged within this range. 21. Flow sensor according to one of the preceding claims, wherein a guide element is arranged in the interior of the second housing part (27). 22. Flow sensor (10) with a passage defining a cylindrical housing (10) having a first passage opening (13) and a second passage opening (29), a flow resistance (23) arranged in the passage of the housing, which divides the housing into a first and a second housing part (11 and 27), a first connection point (17) with a connection to the interior of the first housing part (11), and a second connection point (19) with a connection to the interior of the second housing part, characterized in that a guide element (51) is arranged in the interior of the second housing part (27). 23. flow sensor according to one of claims 21 to 22 wherein the guide element (51) consists of several cooperating parts. 24. Flow sensor according to one of claims 21 to 23 wherein the guide element extends in the flow direction in the housing passage and thereby divides the passage of the housing into passage chambers, and wherein the guide element has a plane of symmetry which through the axis of the through hole (29) and the center of the Opening (28) is clamped. 25. Flow sensor according to one of claims 21 to 24 wherein the guide element is formed as a plate, which divides the passage of the housing part in sections into two mirror images juxtaposed passage chambers, which lie in their extension to the left and right of the openings (28). 26. Flow sensor according to one of claims 21 to 25 wherein the guide element in the direction of the passage opening (29) is spaced from the inner housing to allow insertion of a piece of tubing. 27. Use of the flow sensor according to one of the preceding claims, characterized in that the first housing part 11 on the device side and the second housing part (27) is connected to the patient side.