Turbine for spirometer

Abstract

A turbine for a spirometer is disclosed. The turbine comprises a hollow tubular body (10) and a rotor (100) for rotation about an axis (12) of the hollow tubular body (10), the rotor (100) being arranged between two deflectors (20, 24), the two deflectors (20, 24) are for rotating air passing through the hollow tubular body (10) and are arranged inside the hollow tubular body (10). The rotor (100) comprises a plurality of blades (110), each blade (110) having an outer edge (112) with an angle (120) of 10 to 45 degrees to the axis (12). Further disclosed is a spirometer comprising the turbine; and an assembly comprising the spirometer and a mobile handheld device comprising a processor.

Description

[0001] TURBINE FOR SPIROMETER

[0002] Technical Field

[0003] The present disclosure relates to spirometers. More particularly, the present disclosure relates to a turbine for a spirometer, to a spirometer with such a turbine, and to an assembly with such a spirometer and a mobile handheld device.

[0004] Background

[0005] Spirometers are used for measuring air flow, for example by a human inhaling or exhaling through a turbine of the spirometer. US3605729 is an example of a tube where air through the tube rotates a rotor with twisted blades. US3792611 and US3922525 illustrate later improvements where a turbine comprises a stator with a plurality of curved vanes to rotate air inhaled or exhaled through the turbine. Two blades are rotated by the rotating air flow and breaks a light beam so that the number of rotations per time unit can be detected. The two blades extend radially out from, and along, the axis of the turbine and are not twisted. These blades extend parallel to the axis of the turbine, because the air must easily pass through the turbine. This is how the turbines are designed still today. US4282883 discloses a spirometer with rotor blades at an angle about 28 degrees and the deflectors not rotating air, and US2021 / 0153774 discloses straight rotor blades and two deflectors rotating the air flow.

[0006] It is a problem how to provide a more sensitive spirometer. A problem is to provide a high detection rate at a low air flow. When the blades rotate slowly because of a low air flow, then it is desirable to have a high detection rate to get an accurate indication of the airflow. At a certain low air flow the blades of the prior art do not rotate, that is they do not start spinning, or they stop spinning, at low air flow. It is further a problem how this can be done without influencing detection of a high flow of air. It is further a problem how to ensure the flow of air passes easily through the turbine of the spirometer.

[0007] A further technical problem is that any modified turbine must work with the requirements of medical regulations. Any solution should preferably work together with existing equipment and uses in the medical field. It is desirable that any solution is simple, not expensive to produce, and is reliable. It is further a technical problem to avoid cumbersome arrangements that are expensive to manufacture or assemble.Summary of the Invention

[0008] It is an object of the present invention to provide to a turbine for a spirometer, a spirometer with such a turbine, and an assembly with such a spirometer and a mobile handheld device comprising a processor. This object can be achieved by the features as defined by the independent claim. Further enhancements are characterized by the dependent claims. The invention is defined by the claims.

[0009] According to one embodiment of the invention, a turbine for a spirometer is provided. The turbine comprising a hollow tubular body 10 and a rotor 100 for rotation about an axis 12 of the hollow tubular body 10. The rotor 100 is arranged between two deflectors 20, 24. The deflectors 20, 24 are for rotating air passing through the hollow tubular body 10 and are arranged inside the hollow tubular body 10. The rotor 100 comprises a plurality of blades 110, each blade 110 having an outer edge 112 with an angle 120 of 10 to 45 degrees to the axis 12. The angle 120 is illustrated in figure 8, each blade 110 is, at least partly, rotated about a radial to the axis 12, the amount of rotation is 10 to 40 degrees, given by the angle 120. A twist of 30 degrees provides good detectable rotation of the rotor 100 for low air flows as well for higher air flows. Each blade 110 of the rotor 100 may, at least partly, comprise a width along a twisted part of each blade 110 that is wider than a width close to the axis 12 and / or a width close to the outer edge 12. The turbine may be for a handheld spirometer, for example a handheld spirometer that is wirelessly connectable to a mobile handheld device 400 comprising a processor.

[0010] According to one embodiment, one or more of the blades 110 may comprise one or more of a rounded corner, a cut off corner 114, an opening 116. According to one embodiment, each blade 110 may gradually twist from zero to an angle 120 of 10 to 45 degrees to the axis 12, preferably to 30 degrees.

[0011] According to one embodiment, the turbine may further comprise two, three, or more, indicator sets 310, 320, 330, each indicator set 310, 320, 330 comprising a light source and a light sensor, each set configured to indicate when a rotating blade 110 breaks the light. Each indicator set 310, 320, 330 may be configured such that they indicate at different times when the rotor 100 rotates. Three indicator sets 310, 320, 330 may be arranged equidistant around the turbine, for example off-set by 120 degrees.

[0012] According to one embodiment, the two deflectors 20, 24 may comprise each an opening 22, 26 narrowing towards the rotor 100, the openings 22, 26 may beconfigured to increase the pressure and flow of air passing from the outside into the hollow tubular body 10.

[0013] According to one embodiment, the rotor 100 may comprise three, four, five, or six blades 110. The rotor 100 may be in the shape of a screw propeller with a plurality of blades 110, preferably a toroidal screw propeller.

[0014] According to one embodiment, the rotor 100 may further comprise, in addition to the plurality of blades 110, a plurality of elements 410, 420 for rotation together with the rotor 100 about the axis 12, the elements 410, 420 being configured for detection by one, or more, sets of light sources and light sensors. The elements 410, 420 may be positioned, preferably along the axis 12, between the two deflectors 20, 24, preferably between the plurality of blades 110 and one of the two deflectors 20, 24. The turbine may further comprise one or more additional sets 340 of light sources and light sensors, additional to sets 310, 3020, 330 configured to indicate when a blade 110 breaks the light. The one or more additional sets 340 may be configured to indicate when an element 410, 420 of the plurality of elements 410, 420 breaks the light. The blades 110 may have a different position than the elements 410, 420 to increases the numbers of indication per rotation, rendering a higher frequency of indications and accuracy at low flow.

[0015] According to one embodiment, the deflectors 20, 24 are configured to redirect air flow in to the hollow tubular body 10 from substantially parallel to the axis 12 to 60 to 90 degrees. Each deflector 20, 24 may be configured such that air flow passing thorough the deflectors 20, 24, coming out in to the hollow tubular body 10, is redirected to follow a helix pattern where the degree of inclination is 60 to 90 degrees, preferably very close to 90 degrees.

[0016] According to one embodiment, the blades 110 of the rotor 100 may be curved or straight. According to one embodiment, the blades 110 may comprise a more rounded outer shape, or a more rectangular outer shape. According to one embodiment, the angle 120 may be constant or change along the radial direction of each blade 110. The angle 120 may gradually increase from the axis 12 to the edge 112. For example, the blade 110 may be straight, zero degrees twist, close to the axis 12 and then be twisted such that the angle 120 gradually increases to 30 degrees at the edge 112.

[0017] According to one embodiment, a spirometer comprises the turbine according to any one of the embodiments disclosed herein. The spirometer may comprise aprocessor 340. The spirometer may further comprise a display 350 and / or a sender / receiver for transferring data wirelessly.

[0018] According to one embodiment, the spirometer may further comprise an elongate body 300 to be handheld by a user, the turbine being arranged on the elongate body 300, wherein the axis 12 is angled about 90 to 110, preferably 100, degrees to the elongate body 300. The spirometer may further comprise a separate and exchangeable mouthpiece 310. The mouthpiece 310 may be a range of mouthpieces of different sizes for different users. The mouthpiece may comprise an oval cross shape for a user’s mouth to make it easier for the user to inhale or exhale. The mouthpiece may comprise one of the deflectors, or an additional deflector, guiding the air flow to the turbine, for example rotating the air to the turbine.

[0019] According to one embodiment, an assembly comprises the spirometer according to any one of the embodiments disclosed herein. The assembly may further comprise a mobile handheld device 400 comprising a processor 410. The mobile handheld device 400 may further comprise a display and / or a sender / receiver for transferring data wirelessly. The mobile handheld device and spirometer may be configured to transfer data, for example electronically and / or wirelessly, between the spirometer and the mobile handheld device.

[0020] According to at least one embodiment, such a turbine may be used for a spirometer and indicate rotation of the rotor 100 frequently at low air flows. The rotor 100 rotates easier at low air flows. This results in that the turbine and the spirometer with the turbine gives more frequent indications representing the air flow through the turbine. At least one embodiment has a high accuracy at low air flows. The turbine may also fit and work together with already existing spirometers. The turbine may be simple, not expensive to produce or assemble, and reliable.

[0021] According to one embodiment, that may be combined with any other embodiment disclosed herein, the material used for the rotor 100 and the deflectors 20, 24 may be heat-resistant. The area of the rotor 100 where the rotor 100 is held by the two deflectors, and the two areas of the two deflectors 20, 24 holding the rotor 100, may comprise a heat-resistant material. The axis of the rotor 100 that supports the the plurality of blades 110 and the parts of the deflectors 20, 24 that support that axis may be made out of a heat-resistant material. The heat-resistant materials used may be plastics, preferably plastics that are configured to be heat resistant, for example heat resistant up to a selected temperature of 100, 150, 200 or 250 degrees Celsius. To reliably operate at the selected temperature continuously, the materialmay have a heat deflection temperature, HDT, exceeding the selected temperature and / or a continuous service temperature, CST, rating of the selected temperature or higher. Plastics that may be used are high-heat engineering thermoplastics or high-performance polymers, which maintain structural integrity, creep resistance, and chemical stability at the selected temperature. A plastic configured to have a good sliding and wear properties due to their low coefficient of friction may be used. This allows for the rotor to rotate very rapidly without the internal failures even when heat is created by the rapid rotation. This also avoids thermal degradation.

[0022] At least one of the above embodiments provides one or more solutions to the problems and disadvantages with the background art. Other technical advantages of the present disclosure will be readily apparent to one skilled in the art from the following description and claims. Various embodiments of the present application obtain only a subset of the advantages set forth. No one advantage is critical to the embodiments. Any claimed embodiment may be technically combined with any other claimed embodiment or embodiments.

[0023] Brief Description of the Drawings

[0024] The accompanying drawings illustrate presently exemplary embodiments of the disclosure and serve to explain, by way of example, the principles of the disclosure.

[0025] Fig. 1 is a diagrammatic illustration of a turbine according to an exemplary embodiment of the disclosure;

[0026] Fig. 2 is a diagrammatic illustration of a turbine according to an exemplary embodiment of the disclosure;

[0027] Fig. 3 is a diagrammatic illustration of a cut through view of a turbine according to an exemplary embodiment of the disclosure;

[0028] Fig. 4 is a diagrammatic illustration of a turbine according to an exemplary embodiment of the disclosure;

[0029] Fig. 5 is a diagrammatic illustration of a turbine according to an exemplary embodiment of the disclosure;

[0030] Fig. 6 is a diagrammatic illustration of a cut through view of a turbine according to an exemplary embodiment of the disclosure;

[0031] Fig. 7 is a diagrammatic illustration of a rotor according to an exemplary embodiment of the disclosure;

[0032] Fig. 8 is a diagrammatic illustration of a rotor according to an exemplary embodiment of the disclosure;Fig. 9 is a diagrammatic illustration of a rotor according to an exemplary embodiment of the disclosure;

[0033] Fig. 10 is a diagrammatic illustration of an arrangement of indicator sets and the rotor within the turbine according to an exemplary embodiment of the disclosure;

[0034] Fig. 11 is a diagrammatic illustration to explain the resulting indications as the rotor rotates within the turbine according to an exemplary embodiment of the disclosure; and

[0035] Fig. 12 is a diagrammatic illustration of an assembly of a spirometer and a mobile handheld device according to an exemplary embodiment of the disclosure.

[0036] Detailed Description

[0037] Figures 1 to 3 illustrate one embodiment and figures 4 to 6 illustrate a second embodiment. The cut through view in figure 3 is indicated in figure 2. The cut through view in figure 6 is indicated in figure 5. The different embodiments of the rotor illustrated in figures 7 to 9 may be used in any of the two embodiments in figures 1 to 6. Figures 10 and 11 illustrate an example of an arrangement of indicator sets and the rotor within the turbine and the resulting indications as the rotor rotates within the turbine and passes through the indicator sets. Figure 12 is a diagrammatic illustration of an assembly of a spirometer with the turbine and a mouthpiece. The assembly also comprises a schematic illustration of a mobile handheld device 400 with a processor.

[0038] According to one embodiment, a turbine for a spirometer is provided. The turbine comprising a hollow tubular body 10 and a rotor 100 for rotation about an axis 12 of the hollow tubular body 10. The axis 12 is the central axis of the hollow tubular body 10. The rotor 100 is arranged between two deflectors 20, 24. The two deflectors 20, 24 are for rotating air passing through the hollow tubular body 10 and are arranged inside the hollow tubular body 10. The rotor 100 comprises a plurality of blades 110, each blade 110 having an outer edge 112 with an angle 120 of 10 to 45 degrees to the axis 12. The angle 120 may best be taken from figures 7 and 8. This allows the rotor 100 to rotate also with a low air flow, when only a small amount of air is passing trough the hollow tubular body 10.

[0039] According to one embodiment, one of the two deflectors 20 may be arranged at one end opening 14 of the hollow tubular body 10 and the other deflector 24 may be arranged at, or in the vicinity of, the other end opening 16 of the hollow tubular body 10. One of the two deflectors 20 may be arranged in one opening 14 and theother deflector 24 may arranged in the other opening 16 of the hollow tubular body 10. As may be taken from the figures 1 to 6, the openings 14, 16 are part of the hollow tubular body 10, one opening 14 being at one end of the hollow tubular body 10 and the other opening 16 being at the opposite end of the hollow tubular body 10. A deflector may comprise a plurality of angled blades arranged to rotate air flow forced through the deflector. The rotating air flow then rotates the rotor 100 with its two, or more, blades 110 since the blades 110 are in the rotating air flow.

[0040] The angle 120 is best illustrated in figures 7 and 8. Here each blade 110 is, at least partly, rotated about a radial to the axis 12. The amount of rotation is 10 to 45 degrees, given by the angle 120. Viewed along one blade 110, the extension of the edge 112 crosses the extension of the axis 12, and makes an angle 120 there between, as illustrated in figure 8. The angle 120, the pitch of the rotor blades 110, is between 10 to 45 degrees, and a preferred angle is about 30 degrees. The angle 120 may also be referred to as the amount that the rotor blade 110 is twisted. Such a rotated blade 110 may provide a flat side of the blades 110 that somewhat faces the exit / entrance openings of the deflectors, and therefore the air flow through the turbine. These angles 120 of the blades 110 provide a good rotation speed of the rotor 100 at low air flows, but also a good rotation speed at high air flows. Each blade 110 may have an increase of the angle 120 from zero degrees at, or close by, the axis 12 to 30 degrees, or 10 to 45 degrees, at the edge 112. The increase may be linear or larger or smaller closer to the axis 12. The rotor 100 may comprise a central part, with the axis 12 going through the central part, that is thicker than the rest of the rotor 100. The rotor 100 may be less than one millimetre thick. The outer edge 112 may be the edge 112 at the radial end of each blade 110.

[0041] According to one embodiment, each blade 110 of the rotor 100 may, at least partly, comprise a width along a twisted part of each blade 110 that is wider than a width close to the axis 12. Each blade 110 of the rotor 100 may extend as much as possible in the available space between the two deflectors, inside the turbine, and can therefore be wider than a traditional rotor that has no angle since the width of a traditional rotor blade cannot be more than the distance between the two deflectors. The length of the edge 112 may be longer, because of the twist, than a traditional rotor that has no angle. The rotor 100 may therefore have a width that is at least partly wider than the distance between the two deflectors. The rotor 100 may have a width that is at least partly 90 to 120 percent of the distance between the two deflectors. The length, in the radial direction, of each blade 110 may extend from theaxis 12, the centre of the rotor 100, to near the inner wall of the hollow tubular body 10. The width of the blade 110 may be wider at the centre, close to the axis 12, to reinforce the attachment of each blade 110 of the rotor 100 to the centre of the rotor 100 along the axis 12.

[0042] According to one embodiment, the rotor 100 may be balanced around the axis 12. Each blade 110 may be identically shaped and weigh the same amount. This provides a smooth rotation without any vibrations or other disturbances. According to one embodiment, and as may be taken from figures 3, and 6 to 10, the rotor 100 may have two blades 110, each blade 110 opposite the other. Each blade 110 extending from the middle of the rotor 100.

[0043] Turning to figures 1 to 6, the hollow tubular body 10 has a through opening. In the through opening one of the deflector 20 is arranged close to one end opening 14. In the through opening the other deflector 24 is arranged close to, or a bit further in from, the other end opening 16. The deflectors 20, 24 rotates the air a user exhales, or inhales, through the turbine. The central axis of the hollow tubular body 10 is the axis 12 and the rotor 100 rotates about the axis 12. The outside of the hollow tubular body 10 may have two, three, or four, L-shaped slots 11. These slots 11 may assist to arrange the turbine within a spirometer. Any other connection for arranging the turbine within a spirometer may be used, for example a snap connection or a screw connection. The snap connection may be a sliding movement of the turbine into an elongate body 300 along the axis 12. While the embodiment in figures 1 to 3 is in principle similar to the embodiment in figures 4 to 6, the major difference is that the two deflectors may be cone shaped. The turbine according figures 4 to 6 may comprise the two deflectors 20, 24 comprising each an opening 22, 26 narrowing towards the rotor 100, the openings 22, 26 being configured to increase the pressure and flow of air passing from the outside into the hollow tubular body 10. This may speed up air that flow slowly through the turbine and rotate the rotor 100 faster.

[0044] According to one embodiment, one or more blades 110 may comprise one or more of a rounded corner, a cut off corner 114, an opening 116. This promotes rotation of the rotor because it reduces weight and provides less inertia. As may best be taken from figure 9 one or more corners 114 may be cut off or rounded off. Preferably this is made consistently for all blades 110 of the rotor 100 to keep the rotor well balanced around the axis 12. One or more openings 116 may be made correspondingly in each blade 110 for the same reasons. The openings 116 may be through openings or just thinning of the blade thickness. The openings 116 may beround or rectangular, or any other shape. The openings 116 may be situated closer to the axis 12 than to the edge 112 on each blade 110.

[0045] According to one embodiment, the turbine may further comprise two, three, or more, indicator sets 310, 320, 330. Each indicator set 310, 320, 330 may comprise a light source and a light sensor, and each set may be configured to indicate when a rotating blade 110 breaks the light. Three indicator sets 310, 320, 330 are illustrated as dotted arrows 310, 320, 330 in figure 10, where the light source may throw a light beam in the direction shown by the dotted arrow to the light sensor. The indicator sets 310, 320, 330 are arranged such that the blades 100 breaks the light beam. While three indicator sets have been illustrated in figure 10, the turbine may comprise two indicator sets, or the turbine may comprise four indicator sets.

[0046] According to one embodiment, each indicator set 310, 320, 330 may be configured such that they indicate at different times when the rotor 100 rotates. When each blade 110 starts to break the light beam of any indicator set 310, 320, 330 may be different. There may, for example, be one indicator set more than the numbers of blades 110, for example two blades 110 and three indicator sets 310, 320, 330. The indicator sets 310, 320, 330 may be positioned equidistant around the turbine, for example as illustrated in figure 10 at 120 degrees when there are two blades 110.

[0047] According to one embodiment, there may be three indicator sets 310, 320, 330 positioned equidistant around the turbine, off-set by 120 degrees. As illustrated in figure 10, each indicator set is 120 degrees from the other two. A further example may be to have four indicator sets. This is not illustrated. With four indicator sets the off-set would be 90 degrees. With two indicator sets the off-set would be any off-set besides 180 degrees.

[0048] Turning to figure 11, the resulting indications sensed by the three indicator sets as the rotor rotates within the turbine are illustrated. Each of the three lines correspond to what the light sensor senses and illustrate when the light beam is broken by the blade 110. The lower part of each line indicates that the light beam reaches the light sensor and the higher part indicates that the light beam is broken by a blade 110 of the rotor 100. For example, the position of the rotor 100 in figure 10 is indicated by letter Y in figure 11. As indicated at Y in figure 11, and shown in figure 10, all three light beams are broken by blades 110 of the rotor 100. Figure 11 also illustrates the output of the light sensors when the rotor rotates in one direction and then changes direction at X and rotates in the opposite direction. As may betaken from figure 11, the direction of rotation may also be taken from the output signals of the light sensors. This arrangement contributes to a high number of indications per rotation.

[0049] According to one embodiment, the two deflectors 20, 24 may comprise each an opening 22, 26 narrowing towards the rotor 100. The openings 22, 26 may be configured to increase the pressure and flow of air passing from the outside into the hollow tubular body 10. As best taken from figure 6, a central body of a deflector 20, 24 may be cone shaped, with the cone pointing out from the hollow tubular body 10. A plurality of blades may extend radially outwards from the cone and may be arranged for rotating air flow forced through the deflector 20, 24. The cone shaped body may compress the air when passing by the rotor 100 and this may provide more air to rotate the rotor at low air flows.

[0050] According to one embodiment, the rotor 100 may comprise three, four, five, or six blades 110. The number of blades 110 increases the numbers of indication per rotation, thus higher frequency of indication when the rotor 100 rotates. All blades 110 may be identical and equidistant radiate around the axis 12. The rotor with the blades 110 may be balanced to give a smooth rotation about the axis 12.

[0051] According to one embodiment, the rotor 100 may be in the shape of a screw propeller with a plurality of blades 110. The pitch of the blades 110 may be 20 to 40 degrees, preferably 30 degrees. The pitch should be the same for all blades. The rotor 100 may be in the shape of a toroidal screw propeller with a plurality of blades 110.

[0052] According to one embodiment, the rotor 100 may further comprise, in addition to the plurality of blades 110, a plurality of elements 410, 420 for rotation together with the rotor 100 about the axis 12. The elements 410, 420 may be configured for detection by one, or more, sets of light sources and light sensors. These sets are in addition to the indicator set 31, 320, 330 mentioned herein, but function in a corresponding manner. The elements 410, 420 may be positioned, preferably along the axis 12, between the two deflectors 20, 24. The elements may be position between the plurality of blades 110 and one, or both, of the two deflectors 20, 24.

[0053] According to one embodiment, the turbine may further comprise one or more additional sets 340 of light sources and light sensors, additional to the indicator sets 310, 3020, 330 configured to indicate when a blade 110 breaks the light. The additional one or more sets 340 being configured to indicate when an element 410, 420 of the plurality of elements 410, 420 breaks the light. The indicator sets 310,3020, 330 may be configured to indicate when a blade 110 breaks the light, and the additional sets 340 of light sources and light sensors may be configured to indicate when an element 410, 420 breaks the light. This results in a higher frequency of indications, even if the rotor 100 rotates very slowly. The blades 110 may have a different position than the elements 410, 420 to increases the numbers of indication per rotation, rendering a higher frequency of indications and accuracy at low flow.

[0054] According to one embodiment, the deflectors 20, 24 may be configured to redirect air flow in to the hollow tubular body 10 from substantially parallel to the axis 12 to 60 to 90 degrees. The deflectors 20, 24 may be configured such that air flow passing thorough one of the deflectors 20, 24 comes out and follows a helix pattern where the degree of inclination is 60 to 90 degrees, preferably close to 90 degrees.

[0055] According to one embodiment, a spirometer comprises the turbine according to any one of the embodiments described herein. The spirometer may comprise a processor 340. The spirometer may comprise a display 350. The turbine may be an exchangeable turbine, for example two or three L-shaped slots 11 on the turbine may be used to detachably fasten the turbine to a spirometer body 300. The spirometer may further comprise an elongate body 300 to be handheld by a user. The entire spirometer, including the turbine, may be handheld, for example handheld and mobile. The elongate body 300 may be configured to be held by a user’s hand and may be configured to hold the hollow tubular body 10. The turbine may be arranged on the elongate body 300. The axis 12 may be angled about 90 to 110, preferably 100, degrees to the elongate body. As may best be taken from figure 12, a central axis 320 of the elongate body 300 has an angle 330 of about 100 degrees to the axis 12 of the hollow tubular body 10 of the turbine. This provides a straight entry into the turbine of any air exhaled by a user. The user’s air flow may therefore advantageously be parallel to axis 12.

[0056] According to one embodiment, the spirometer may further comprise a separate and exchangeable mouthpiece 310. The mouthpiece 310 may be different sizes, for example for adults or for children. The mouthpiece 310 may also be an exchangeable single use mouthpiece made out a biodegradable material, such as for example paper. One end of the mouthpiece 310 may be attachable to the hollow tubular body 10 or to the elongate body 300. The other end of the mouthpiece 310 may comprise an oval cross section for a user’s mouth. According to one embodiment, the mouthpiece 310 may comprise one of the deflectors 20,24. The deflector may form a rotating air flow into the turbine when a user is blowing into themouthpiece 310. According to one embodiment, the mouthpiece 310 may comprise an additional deflector guiding the air flow to the turbine. The additional deflector may form a laminar air flow to the turbine, or may form a rotating air flow to the turbine.

[0057] According to one embodiment, an assembly comprises the spirometer according to any one of the embodiments disclosed herein and further a mobile handheld device 400 comprising a processor 410. The mobile handheld device 400 and spirometer may be configured to transfer data between the spirometer and the mobile handheld device. The data transfer may be done electronically and / or wirelessly. The transfer data between the spirometer and the mobile handheld device may comprise the frequency of indications. For example, the data may include the rotational speed of the rotor 100. The assembly may be handheld and mobile. The spirometer may be handheld with one hand, and the mobile handheld device 400 may be handheld with the other hand. The mobile handheld device 400 may be a smart phone. The spirometer may be configured to display the resulting measurement of the air flow through the turbine on the display 350. In addition, or as an alternative, the spirometer may be configured to send the resulting measurement of the air flow through the turbine to the mobile handheld device 400.

[0058] The rotor 100 may be injection moulded. According to one embodiment, an injection moulded tool for injection moulding the rotor 100 according to any embodiment disclosed herein is provided. The hollow tubular body 10 and the two deflectors 20, 24 may also be injection moulded using injection moulding tools. Injection moulding is still possible and economic when the twist of each blade 110 is within the angle 120 of 10 to 45 degrees to the axis 12.

[0059] According to one embodiment, the blades 110 of the rotor 100 may be curved or straight. For example, each blade 110 may be straight along the radial direction from axis 12. For example, each blade 110 may be curved along the radial direction from axis 12. In such a case, the curvature may be towards, or away, from a deflector, or the curvature may be towards any other direction.

[0060] According to one embodiment, the blades 110 may comprise a more rounded outer shape, or a more rectangular outer shape. As may best be taken from figures 7 to 9, the outer shape, of which the edge 112 and the axis 12 form part, is substantially rectangular. The outer shape may be substantially oval or round.

[0061] According to one embodiment, the angle 120 may be constant or change along the radial direction of each blade 110. The angle 120 may be less closer to the edge112 and larger closer to the axis 12. The angle 120 may be in the range 10 to 45 degrees. For example, the angle 120 may be 35 degrees close to the axis 12 and 20 degrees at the edge 112. The change of the angle 120 from close to the axis 12 to the edge 112 along the radial direction may be constant. The angle 120 may gradually increase from the axis 12 to the edge 112. For example, the blade 110 may be straight close to the axis 12 and then be twisted such that the angle 120 gradually increases to 30 degrees at the edge 112.

[0062] According to one embodiment, one or more, or all, surfaces on the inside of the turbine where air passes by may not be smooth. The surface or surfaces may comprise projections or dimples or indentations, or any combination thereof. The surface or surfaces may be uneven or rough.

[0063] At least one embodiment provides that the rotor 100 rotates during a very low air flow through the hollow tubular body 10. This produces a good number of indications per time unit at low air flows. The blades 110 having an angle rotate partly because of the rotating air flow created by the deflector and partly because the air flow is forced through the hollow tubular body 10. Using two, or preferably three, indicator sets 310, 320, 330 will render more indications at low air flows due to the rotation of the rotor 100 and give a higher frequency of indications.

[0064] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using the turbine. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1.Claims1 A turbine for a spirometer, the turbine comprising a hollow tubular body (10) and a rotor (100) for rotation about an axis (12) of the hollow tubular body (10), the rotor (100) being arranged between two deflectors (20, 24), the two deflectors (20, 24) are configured for rotating air passing through the hollow tubular body (10) and are arranged inside the hollow tubular body (10);characterised in that the rotor (100) comprises a plurality of blades (110), each blade (110) having an outer edge (112) with an angle (120) of 10 to 45 degrees to the axis (12).2 The turbine according to claim 1, wherein one or more blades (110) comprises one or more of a rounded corner, a cut off corner (114), an opening (116).3 The turbine according to claim 1 or 2, further comprising two, three, or more, indicator sets (310, 320, 330), each indicator set (310, 320, 330) comprising a light source and a light sensor, each set configured to indicate when a rotating blade (110) breaks the light.4 The turbine according to claim 3, wherein each indicator set (310, 320, 330) is configured such that they indicate at different times when the rotor (100) rotates.5 The turbine according to claim 3 or 4, wherein three indicator sets (310, 320, 330) are arranged equidistant around the turbine, off-set by 120 degrees.6 The turbine according to any one of the preceding claims, wherein the two deflectors (20, 24) comprise each an opening (22, 26) narrowing towards the rotor (100), the openings (22, 26) thereby being configured to increase the pressure and flow of air passing from the outside into the hollow tubular body (10).7 The turbine according to any one of the preceding claims, wherein the rotor (100) comprises three, four, five, or six blades (110).8 The turbine according to any one of the preceding claims, wherein the rotor (100) is in the shape of a screw propeller with a plurality of blades (110), preferably a toroidal screw propeller.9 The turbine according to claim 1, wherein the rotor (100) further comprises, in addition to the plurality of blades (110), a plurality of elements (410, 420) for rotation together with the rotor (100) about the axis (12), the plurality of elements (410, 420) being configured for detection by one, or more, sets of light sources and light sensors, the elements (410, 420) being positioned between the two deflectors (20, 24), preferably between the plurality of blades (110) and at least one of the two deflectors (20, 24).10 The turbine according to claim 9, further comprising one or more additional sets (340) of light sources and light sensors, additional to the indicator sets (310, 3020, 330) configured to indicate when a blade (110) breaks the light, the additional one or more sets (340) being configured to indicate when an element (410, 420) of the plurality of elements (410, 420) breaks the light.11 The turbine according to any one of the preceding claims, wherein the deflectors (20, 24) are configured to redirect air flow in to the hollow tubular body (10) from substantially parallel to the axis (12) to 60 to 90 degrees.12 A spirometer comprising the turbine according to any one of the preceding claims, the spirometer comprises a processor (340) and optionally a display (350).13 The spirometer according to claim 12, the spirometer further comprising an elongate body (300) to be handheld by a user, the turbine being arranged on the elongate body (300), wherein the axis (12) is angled about 90 to 110, preferably 100, degrees to the elongate body (300).14 The spirometer according to claim 12 or 13, further comprising a separate and exchangeable mouthpiece (310), preferably with an oval cross section for a user’s mouth.15 An assembly comprising the spirometer according to any one of the claims 12 to 14 and a mobile handheld device (400) comprising a processor (410), the mobile handheld device (400) and spirometer being configured to transfer data between the spirometer and the mobile handheld device.

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