Antibacterial filter and turbine flowmeter for tests on respiratory functionality

Abstract

A flowmeter and filter assembly for spirometry have a flowmeter with a turbine rotor and sensor means for detecting the speed of rotation of the rotor, and a filter upstream of the flowmeter. An air-conveying device modifies the direction of the flow of air at an outlet from the filter to set the rotor in rotation within the flowmeter. The air-conveying device is integrated in the filter instead of in the flowmeter.

Claims

1. A disposable filter for spirometry for use in connection to a separate and independent flowmeter for spirometry, the filter comprising: a filter hollow body having a longitudinal axis and defining a passage for a flow of air through the filter hollow body, the filter hollow body further comprising: a filter inlet portion; a filter circular disk portion in fluid communication with and positioned downstream of the inlet portion, the circular disk portion having a peripheral edge radially larger than the inlet portion about the longitudinal axis; a filtering material positioned in the circular disk portion; and a filter tubular outlet portion in fluid communication with and positioned downstream of the circular disk portion, the tubular outlet portion further comprising: a plurality of filter axial tabs extending longitudinally along the longitudinal axis and having a filter outlet end, the plurality of filter axial tabs operable to engage a body of the separate and independent flowmeter; and a filter air-conveying device comprising: a plurality of stationary filter fins rigidly connected to the filter tubular outlet portion, each filter fin connected to a respective filter axial tab and radially and helically extending inward inside the filter hollow body toward and about the longitudinal axis in the flow of air passage, the plurality of stationary fins operable to modify the direction of the flow of air in the passage inside the filter hollow body to a helical direction at the filter hollow body outlet end.

2. The filter according to claim 1 wherein each axial fin further comprises a distal end extended into the filter flow of air passage, the distal end free from connection to other of the plurality of axial fins.

3. The filter according to claim 1 wherein the plurality of filter fins are equally angularly spaced apart from one another about the filter tubular outlet portion.

4. The filter according to claim 1, wherein the filter outlet portion is configured for coupling with a complementary portion defined on an inlet portion of the flowmeter.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further characteristics and advantages of the invention will emerge from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

(2) FIG. 1, already described above, shows the use of a flowmeter provided with an antibacterial filter of the turbine type;

(3) FIGS. 2 and 3 are a perspective view and a side view, respectively, of an antibacterial filter according to the prior art;

(4) FIG. 4 and FIG. 5 are, respectively, a perspective view and a cross-sectional view and at an enlarged scale of a turbine flowmeter according to the prior art;

(5) FIG. 6 is a schematic cross-sectional view in a plane orthogonal to the axis of the filter that shows the working principle of the sensors of the speed of rotation of the rotor of the flowmeter, provided according to the prior art;

(6) FIGS. 7 and 8 are exploded perspective views of a preferred embodiment of the flowmeter and filter assembly according to the present invention;

(7) FIG. 9 is a side view of the assembly according to the invention in the assembled condition; and

(8) FIGS. 10 and 11 are two further perspective views of the preferred embodiment of the flowmeter and filter assembly according to the invention.

DESCRIPTION OF EMBODIMENTS

(9) In FIGS. 7-11, the parts in common with the ones illustrated in FIGS. 1-6 are designated by the same reference numbers.

(10) FIG. 1 of the annexed drawings, which shows the use of the flowmeter by a patient, also applies to the case of the assembly according to the invention. Also in this case, the assembly comprises a flowmeter B, which can be accommodated within a grip D and is provided with an antibacterial filter C for use by the patient.

(11) With reference to FIGS. 7-11, also in the case of the preferred embodiment of the invention that is illustrated here, the filter C has a hollow body C1, for example made of plastic material, substantially in the form of a circular disk, with a tubular inlet portion C2 and a tubular outlet portion C3 projecting from the opposite faces of the disk body C1 and set coaxially with respect to the latter.

(12) It should be noted that the general conformation of the antibacterial filter C can also be altogether different from the one illustrated herein purely by way of example, the only essential condition, for the purposes of the invention, being that the outlet portion C3 of the antibacterial filter incorporates an air-conveying device DC configured for modifying the direction of flow of air at outlet from the filter C.

(13) In the case of the example illustrated, the conveying device DC comprises three stationary fins W rigidly connected to the body C1 of the filter. The fins W are set at equal angular distances apart about the axis X of the filter C and are shaped for imparting a helical direction on the flow of air at outlet from the filter, such as to set the rotor R of the flowmeter in rotation. The fins W extend in the direction of the axis X starting from respective axial tabs T that project from the end front edge of the tubular outlet portion C3 of the filter C.

(14) With reference once again to FIGS. 7-11, the flowmeter B according to the invention comprises, in the embodiment illustrated, a cylindrical body B1, for example made of plastic material, and in particular of transparent plastic material, having a tubular conformation. The body B1 has an end portion, which is fitted with slight interference on the tubular outlet portion C3 of the filter (FIG. 9). Within the body B1 of the flowmeter, a rotor R is rotatably mounted about the axis X of the flowmeter (see FIG. 9). The rotor is carried by a shaft that is mounted so that it can rotate freely within the body B1 of the flowmeter B. For this purpose, one end of the shaft of the rotor is rotatably supported by the hub of an air-conveying device B5 similar to that of the conventional flowmeter that has been described in greater detail above and is mounted within the outlet end of the flowmeter B, i.e., downstream of the rotor. Upstream of the rotor, the flowmeter B is without any air-conveying device, the corresponding end of the shaft of the rotor being supported in rotation by a supporting body S inserted within the flowmeter B, which does not have any function of conveying the flow of air; i.e., it is not able to modify to any great extent the direction of the flow of air. The support S comprises three peripheral tabs T that are inserted into the respective compartments comprised between the tabs T of the filter in the condition where the flowmeter is coupled to the filter, in which the cylindrical wall of the body B1 of the flowmeter is set on the outside of the cylindrical outlet portion C3 of the filter, and the tabs T of the flowmeter are inserted between the tabs T projecting from the front edge of the tubular outlet portion C3 of the filter.

(15) Hence, as emerges clearly from the drawings, the disposable filter C is made for being uniquely coupled to the flowmeter B that has been described previously.

(16) As already mentioned, the only essential characteristic for the purposes of the present invention lies in the fact that the air-conveying device set upstream of the rotor of the flowmeter is integrated in the outlet portion of the filter instead of being provided in the flowmeter. Of course, without prejudice to said essential characteristic, the details of construction and the embodiments both of the filter and of the flowmeter, as well as of the parts for coupling between the flowmeter and the filter, can vary widely with respect to what has been described herein purely by way of example.

(17) Furthermore, even though the invention has been devised particularly for use of a disposable filter, it is not ruled out that it may be used also for a non-disposable filter.

(18) As is evident from the foregoing description, the invention opens the way to a new generation of filters, which are characterized not only in that they perform a filtering function but also in that they integrate an air-conveying device that is able to modify the direction of the flow of air at outlet from the filter in order to set the rotor of the flowmeter connected to the filter in rotation. Said solution renders production of filters with materials and constructional techniques of good quality compulsory also in the case of filters of a disposable type, a fact that guarantees an optimal performance and a high reliability as regards the measurements made and in terms of safety for the patient.