DE102010064624B3 - Flow sensor with two connecting pieces arranged on a flange extension and aligned parallel to the longitudinal axis - Google Patents

Abstract

A flow sensor (10) for determining the breathing air flow of a patient, said flow sensor (10) having a cylindrical housing defining passage with a first passage opening (13) adapted for connection of a device side air supply tube, and a second passage opening (29), which Connection of a patient-side air supply tube is formed, and having a arranged in the passage of the housing flow resistance (23), wherein the housing is a two-part housing and a first through-opening (13) exhibiting first housing member (11) and the second through-hole (29) comprising second housing component (27), on each of which for connection of the housing components (11, 27) flanges (15, 31) are formed with opposing flange surfaces, wherein the flow resistance (23) the housing in a first housing part and a second Housing part, said flow sensor (10) further having a first connection point (17) with a first connection point connection to the interior of the first housing part and a second connection point (19) with a second connection point connection to the interior of the second housing part and 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 are formed, wherein the first and the second connection point (17, 19) at a distance arranged on each other on the same housing member (11) and the first and the second connecting piece (18, 20) are aligned parallel to the longitudinal axis of the housing, characterized in that the flanges (15, 31) each extending in the direction away from the passage flange extension have, wherein the first and the second connection point (17, 19) on Flanschfo Set of the first housing component (11) are arranged.

Description

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

A flow sensor is from the patent US 4 083 245 A known. 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 sensors is the risk of kinking 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 based on the fact 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.

From the US Pat. No. 6,585,662 B1 a generic flow sensor is known, which is suitable and designed for determining a breathing air flow of a patient. The flow sensor known from this publication also has two housing components, which are connected to one another along each of the two housing components at their mutually facing zuenden longitudinal ends flange. The flanges on the two housing components not only serve to connect the two housing components with each other, but also serve as a clamping device for clamping a fabric or lattice-like flow resistance, which consequently passes through the fully located within the flanges region of the flow sensor.

This permeates the flow resistance of the US Pat. No. 6,585,662 B1 known flow sensor also connection point connections, which connect connection points for connecting a connecting line to the flow sensor for connection to a pressure sensor with the interior of the housing. Thus, the connecting line between the pressure sensor and the interior of the housing of the subject US Pat. No. 6,585,662 B1 known flow sensor as the effect of the flow resistance as the passage for the breathing gas. Therefore, the connection points for connection to the pressure sensor must be protected against contamination by a bacterial filter.

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 by a flow measuring sensor with all features of claim 1.

Advantageous developments of the invention are specified in the subclaims.

The first and second connection points for sensor hoses 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.

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

According to the invention, 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.

According to the invention, 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. It is possible, for example, to design the housing parts in an application-specific manner, ie. H. Connection shapes and sizes can be selected and combined according to customer requirements. Appropriately, both housing parts may have the same or different shape and / or size on the opposite ends. Through-holes 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 agents are conveniently on the surfaces, d. H. 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 cohesive connection of these profiles.

Advantageously, profile structures - consisting of elevations - and groove structures - consisting of depressions - for receiving material on the pressure surfaces of the first flange and the second flange are mutually complementarily arranged so that a maximum material bond when connecting the two flange surfaces is achieved.

According to the invention, a first connection leads from the first connection point to a first opening in the interior of the first housing part and from the second connection location 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. H. 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 constructed 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, d. H. 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 which open onto the flange, by continuous surface structures, for. B. survey structures or groove structures bordered. This will turn on in the assembled flow sensor disturbing, which prevents measurement results distorting influence 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 form a connection to the interior of the second housing part, are jointly enclosed by a second uninterrupted structure; and the through opening of the cylindrical housing are enclosed by another continuous structure, said structures having opening groups, i. H. 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 are arranged in the interior of the housing parts in each case the same distance to the flow resistance opposite one another. This increases the measurement accuracy of the pressure difference.

Advantageously, both connections to the interior of the housing parts have the same 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 middle 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, it remains in the flow sensor and thus can not enter the respiratory tract of the patient.

In one embodiment, a guide element is arranged in the flow sensor 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 tube section lying in front of the opening. It is believed that existing flow or transverse flow fractions 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 hose section located in front of the opening. 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 flowmeter 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, 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 into passage chambers, so that the guide element has a plane of symmetry which is spanned by the axis of the passage opening and the center of the opening. Through this arrangement of the guide element, which is symmetrical to the opening, an air flow which is equally symmetrical to the opening is obtained. This results in better reproducible measurement results.

In a preferred embodiment, the guide element is formed as a 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 positional 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 use in practice handle. There is no need for a further adapter: the breathing tube and the flowmeter are directly connected. The length of the tube system between flow sensor and lung can be further reduced, which in turn results in a reduction of 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 the invention, the first housing part is connected on the device side and the second housing part on the patient side. The measuring tubes, which lead to the differential pressure gauge, can be led away from the patient directly and parallel to each other. The risk of kinking this is reduced. The comfort for patient and nursing staff increased. When using the guide element described above, the air flow of the exhaled air is aligned by the 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 present invention solves known problems involving the location and length of the tubing system.

In the following, the invention will be described in more detail in a schematic representation with reference to the figures. It shows:

1 : Perspective view of a flow sensor in three parts;

2 : Longitudinal section through the composite flow sensor;

3 : Housing-side housing part in perspective view;

4a : Front view and top view of the device-side housing part;

4b : Longitudinal section of the device-side housing part;

5 : Patient-side housing part in perspective view;

6a : Front view and top view of the patient-side housing part;

6b : Longitudinal sections of the patient-side housing part of 6a ;

7 : Patient-side housing part in perspective view with guide element

8a : Front view and top view of the patient-side housing part with guide element;

8b : Longitudinal sections of the patient-side housing part of 8a ;

9 : Longitudinal section through the composite flow sensor with guide element.

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 ) of 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 ) arises. The second housing part ( 27 ) has a passage opening ( 29 ) with connection to the patient-side air supply tube (not shown), a second flange ( 31 ) with flange extension ( 32 ), a second connection channel ( 33 ) (here only the sealing surface side opening to see) of 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 ) there are two slots (first slot ( 35 ) and second slot ( 37 )) - as shown below - the connection from the connection points (first connection point ( 17 ) and second connection point ( 19 )) to the connection channels (first connection channel ( 21 ) and second connection 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 )) Pencils 41 (please refer 4b ) and matching recesses ( 39 ), which ensure both the positioning of the flow resistance with respect to the housing parts as well as the mutual positioning of the two housing parts.

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

In 3 is shown in a further perspective view of the first housing part. Here is the non-central arrangement of the sealing surface side opening of the first connection channel ( 21 ) between the connection points ( 17 ) and ( 19 ) illustrates. In 4a It can also be seen that the connection channel ( 21 ) to the interior of the first housing part ( 11 ) leads. The inside opening ( 12 ) lies in the middle under the first flange extension ( 16 ).

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

In 5 is shown in a further perspective view of the second housing part. The non-central arrangement of the second connection channel ( 33 ) with respect to the flange extension ( 32 ) is recognizable. In 6a It can also be seen that the connection channel ( 33 ) to the interior of the second housing part ( 27 ) leads. The inside opening ( 28 ) lies in the middle under the second flange extension ( 32 ).

As in 6a . 6b and 6c visible, continuous groove structures ( 47 ) at the outer edge of the sealing surfaces of the second flange ( 31 ) and its extension ( 32 ) along. In addition, the seal-side openings of the slots ( 35 . 37 ) and the connection channel ( 33 ) with the groove structure ( 47 ) so bordered that on the one hand, the seal-side opening of the first slot ( 35 ) is enclosed with the groove structure and separated from the other, the two seal-side openings of the second slot ( 37 ) and the second connection channel ( 33 ) with the groove structure ( 47 ) are enclosed. Furthermore, in 6a and 6c Positioning recesses ( 39 ) recognizable. 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 . 1 ) with its recesses ( 49 ) and the second housing part ( 27 ) with its recesses ( 39 ) on the pins 41 ( 4a ) of the first housing part ( 11 ). As a result, the first housing part ( 11 ) and second housing part ( 27 ) and suitably positioned on each other and connected to each other materially and airtight. In this cohesive arrangement, the first connection point ( 17 ), the first slot ( 35 ) and the first connection channel ( 21 ) so that a gas pressure exchange between the interior of the first housing part ( 11 ) and a pressure sensor hose, which at the first connection point ( 17 ) is possible. Furthermore, the second connection point ( 19 ), the second slot ( 37 ) and the second connection channel ( 33 ) so that a gas pressure exchange between the interior of the second housing part ( 27 ) and a sensor tube, which at the second connection point ( 19 ) is possible. With this arrangement, a pressure sensor makes it possible to measure continuously or from time to time a pressure difference between the interior spaces of the first and second housing parts, ie 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, in the interior of the second housing part ( 27 ) a guiding element ( 51 ) arranged. This in 7 . 8a . 8b and 9 Guide element shown is formed as a small plate. This plate acts as a flow straightener and is in the flow direction in the interior of the second housing part ( 27 ). As in 8a and 8b illustrated, the housing passage through the guide element ( 51 ) in sections into two chambers ( 53 . 55 ) divided up. The guide element is between the connection opening ( 29 ) and the second opening ( 28 ) are arranged in the interior of the second housing part. As in 8a seen, the tile is aligned on the plane passing through the axis ( 57 ) of the passage opening ( 29 ) and the midpoint ( 59 ) of the opening ( 28 ) is formed. The guiding element ( 53 ) is connected at two of its opposite edges via tabs with the cylindrical housing wall ( 8b ). Towards the connection opening, the guide element is designed as a free-standing nose. According to 8b is the guide element in the passage direction of the second opening ( 28 ) in the interior of the second housing part by approximately the diameter of that opening ( 28 ) spaced. In 9 is a section through the entire flow sensor shown. The guiding element ( 51 ) is 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 ) arise from the flange extension.

Such a guide can also be integrated in commercially available flow sensors. For example, such a guide element as a variant in the known flow sensor according to patent document US 4 083 245 (especially after 1 and claims 1 to 5).

LIST OF REFERENCE NUMBERS

10

Cylindrical housing

11

First housing part

12

First opening in the interior of the first housing part

13

Connection opening to the device-side air supply tube

15

First flange, with first flange surface

16

First flange extension, with first flange extension surface

17

First connection point

18

First connection piece

19

Second connection point

20

Second connection piece

21

First connection channel

23

flow resistance

25

flap

27

Second housing part

28

Second opening in the interior of the second housing part

29

Connection opening to the patient-side air supply tube

31

Second flange, with second flange surface

32

Second flange extension, with second flange extension surface

33

Second connection channel

35

First slot

37

Second slot

39

recesses

41

pencils

43

Ultrasonic weld joint (here a superposition of original weld profile elevation and original groove)

45

Ultrasonic welding profile

47

groove structure

49

recesses

51

vane

53

First passage chamber

55

Second passage chamber

57

Axis of the passage opening ( 29 )

59

Center of the opening ( 28 )

Claims (18)

Flow sensor ( 10 ) for determining the respiratory air flow of a patient, wherein the flow sensor ( 10 ) defining a cylindrical housing defining passage with a first passage opening ( 13 ), which is designed for connection of a device-side air supply tube, and a second passage opening ( 29 ), which is designed to connect a patient-side air supply tube, and with a arranged in the passage of the housing flow resistance ( 23 ), wherein the housing is a two-part housing and a first through-opening ( 13 ) having the first housing component ( 11 ) and a second through-hole ( 29 ) having the second housing component ( 27 ), to which in each case for connecting the housing components ( 11 . 27 ) flanges ( 15 . 31 ) are formed with opposing flange surfaces, wherein the flow resistance ( 23 ) the housing is divided into a first housing part and a second housing part, wherein the flow sensor ( 10 ) a first connection point ( 17 ) with a first connection point connection to the interior of the first housing part and a second connection point ( 19 ) having a second connection point connection to the interior of the second housing part, and wherein the first connection point ( 17 ) as the first connecting piece ( 18 ) and the second connection point ( 19 ) as a second connecting piece ( 20 ) are formed for the connection of a connecting line to at least one pressure sensor, wherein the first and the second connection point ( 17 . 19 ) at a distance from each other on the same housing component ( 11 ) and the first and the second connecting piece ( 18 . 20 ) are aligned parallel to the longitudinal axis of the housing, characterized in that the flanges ( 15 . 31 ) each have a flange extension extending in the direction away from the passage, wherein the first and the second connection point ( 17 . 19 ) on the flange extension of the first housing component ( 11 ) are arranged. Flow sensor according to claim 1, characterized in that on the flanges ( 15 . 31 ) Means for mutual relative alignment of the housing components ( 11 . 27 ) are provided. Flow sensor according to one of claims 1 or 2, characterized in that means are provided for the cohesive connection formation on the flange surfaces. Flow sensor according to claim 3, characterized in that the means for cohesive connection formation consist of groove and welded structure. Flow sensor according to claim 4, characterized in that groove and welded structure on the surfaces of the first flange ( 15 ) and the second flange ( 31 ) are arranged complementary to each other. Flow sensor according to one of the preceding claims, characterized in that the connection point connections run partially in the flange surfaces and / or emerge as openings through the flange. Flow sensor according to claim 6, characterized in that the connection points Connections partially as slots ( 35 . 37 ) in the flange surfaces and partly as channels ( 21 . 33 ) through the housing parts ( 11 . 27 ) are formed. Flow sensor according to one of claims 6 or 7, characterized in that openings ( 17 . 19 . 21 . 33 . 35 . 37 ), which open onto the flange surfaces, by continuous groove structures ( 47 ) or profiling structures ( 45 ) are enclosed. Flow sensor according to one of claims 6 to 8, characterized in that openings ( 17 . 21 ) on the first flange surface, which connects to the interior of the first housing component ( 11 ) are enclosed together by a continuous structure, and wherein openings ( 33 . 37 ) on the second flange surface, which connects to the interior of the second housing component ( 27 ) are bound together by a second uninterrupted structure; and wherein the passage opening of the cylindrical housing is enclosed by a further continuous structure, and these structures delimit said opening groups from one another and either groove structures (FIG. 47 ) or welded structures ( 45 ) are. Flow sensor according to one of the preceding claims, characterized in that at the flange surfaces means for arranging the flow resistance ( 23 ) are provided. Flow sensor according to one of the preceding claims, characterized in that the flanges ( 15 . 31 ) have a diameter which is larger than the housing diameter. Flow sensor according to one of the preceding claims, characterized in that the two housing components ( 11 . 27 ) have different shape and / or size on the opposite ends. Flow sensor according to one of the preceding claims, characterized in that the connection point connections to the interior of the respective housing parts have the same length. Flow sensor according to one of the preceding claims, characterized in that the passage of the housing in the central part has an area of increased diameter, wherein the flow resistance ( 23 ) is arranged within this range. Flow sensor according to one of the preceding claims, characterized in that in the interior of the second housing component ( 27 ) a guiding element ( 51 ) is arranged. Flow sensor according to claim 15, characterized in that the guide element ( 51 ) consists of several interacting parts. Flow sensor according to one of claims 15 or 16, characterized in that the guide element ( 51 ) extends in the direction of flow 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 passes through the axis of the passage opening ( 29 ) and the center of a passage-side opening ( 28 ) of the second connection point connection in the second housing component ( 27 ) is stretched. Use of the flow sensor according to one of the preceding claims, characterized in that the first housing component ( 11 ) on the device side and the second housing component ( 27 ) is connected on the patient side.

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