AU2014255597B2

AU2014255597B2 - Turbine for a respiratory assistance apparatus with reduced noise emissions

Info

Publication number: AU2014255597B2
Application number: AU2014255597A
Authority: AU
Inventors: Pierre-Emmanuel DUBOIS
Original assignee: Air Liquide Medical Systems SA
Current assignee: Air Liquide Medical Systems SA
Priority date: 2013-04-18
Filing date: 2014-03-19
Publication date: 2017-03-30
Anticipated expiration: 2034-03-19
Also published as: FR3004766A1; ES2748353T3; CN105121865A; CA2908673A1; WO2014170571A8; EP2986856A1; FR3004766B1; EP2986856B1; AU2014255597A1; WO2014170571A1

Abstract

The invention concerns a turbine or a micro-blower for a respiratory assistance apparatus comprising an electric motor (1) with a vaned rotor (2) for generating a gas stream; a bellmouth (5) for sucking in gas, such as air, when the vaned rotor (2) is driven in rotation by the electric motor (1); a volute (3, 4) comprising an internal compartment (10) enclosing the vaned rotor (2) and at least one portion of a discharge conduit (7) conveying the gas delivered by said vaned rotor (2). The bellmouth (5) is arranged on the upper portion of the volute (4), and they together define at least one dead volume (6). According to the invention, said dead volume (6) comprises at least one soundproofing material (11) capable of reducing at least a part of the noise emissions generated by the motor (1) and/or the vaned rotor (2) during the rotation of the vaned rotor (2).

Description

1 2014255597 19 Oct 2015

TURBINE FOR A RESPIRATORY ASSISTANCE APPARATUS WITH REDUCED NOISE EMISSIONS

TECHNICAL FIELD

[0001] The invention relates to a micro-fan or turbine intended to equip a respiratory assistance apparatus. More specifically, the invention relates to the use of the dead spaces for acoustic purposes, by adding suitable soundproofing materials to said dead spaces situated between the volute and the bellmouth.

BACKGROUND

[0002] Certain respiratory assistance apparatuses use micro-fans or turbines which serve to generate a pressurized gas, generally air or oxygen-enriched air, which is then sent to the airways of a patient.

[0003] A turbine of this type is notably described by document EP-A-2102504 which teaches a respiratory assistance apparatus allowing a regulated delivery of a gas, notably air, by means of a turbine comprising a casing, an air supply duct delimited by the casing, a volute, the inlet opening of which is in communication with the air supply duct, an impeller, situated immediately downstream of the volute inlet opening, and comprising an inlet opening connected to this inlet opening of the volute and outlet orifices opening into the volute, and a drive motor rotating the impeller so as to generate a centrifugal stream of air in the volute.

[0004] One of the problems that arises with micro-fans or turbines is that of noise emissions, which means to say the noise they generate. Indeed respiratory assistance apparatuses equipped with these micro-fans or turbines are intended to be used in a hospital environment or in the home, and so the noise emitted when the motor is operated and the impeller is turning needs to be as low as possible.

[0005] Solutions have been proposed for this purpose, notably a widespread solution which involves soundproofing the outside of the turbine using a soundproofing housing and/or foams or the like arranged around.

[0006] This does effectively allow the noise to be attenuated but introduces constraints in terms of size, i.e. the volume taken up by foam. C:\pof\word\SPEC-1039965.docx 2 2014255597 02 Mar 2017 [0007a] Any reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.

SUMMARY OF THE INVENTION

[0008] According to the present invention there is provided a turbine for a respiratory assistance apparatus, comprising : - an electric motor collaborating with an impeller to generate a stream of gas, - a bellmouth inlet comprising an inlet opening through which gas is drawn when the impeller is rotationally driven by the electric motor, the impeller being situated immediately downstream of the inlet opening, - a volute comprising a volute lower part and a volute upper part which are coupled to one another and shaped in such a way as to form an internal compartment encompassing the impeller and at least one part of a discharge duct used to carry the gas delivered by said impeller, and - the bellmouth inlet being arranged on the volute upper part while defining at least one dead volume between them, wherein at least one dead volume comprises at least one soundproofing material able to attenuate at least some of the noise emissions generated by the motor and/or the impeller when the impeller is rotating, the soundproofing material being an elastomeric material.

[0009] Depending on circumstances, the turbine or micro-fan of the invention may comprise one or more of the following technical features: - the motor allows the impeller to be driven at a speed of between 0 and 100 000 rpm, typically between 10 000 and 60 000 rpm, - the volute lower part and the volute upper part are held together rigidly, - the acoustic core is trapped between the bellmouth and the volute upper part, - the bellmouth is made of elastomer, - sealing means allow a fluid tight seal to be created between the volute lower part and the external wall of the motor or of a space containing the motor, - the volute lower part and the volute upper part are made of a polymer material, particularly a polycarbonate or ABS. 3 2014255597 02 Mar 2017 [0010] The invention also relates to a respiratory assistance apparatus comprising a turbine according to the invention which in particular is selected from apparatuses of the CPAP (constant air pressure or single air pressure) or BiPAP (two pressure levels) type.

BRIEF DESCRIPTION

[0011] The present invention will now be described in greater detail with reference to the attached figures among which: - figure 1 depicts a schematic view (in cross section) of one embodiment of a microfan or turbine for a respiratory assistance apparatus according to the present invention, and - figure 2 shows a soundproofing material arranged between the volute and the bellmouth of the turbine of figure 1.

DETAILED DESCRIPTION

[0012] Figure 1 schematically depicts one embodiment of a micro-fan or turbine according to the invention equipping a respiratory assistance apparatus comprising an electric motor 1 which, via its rotary shaft 8, drives an impeller 2 used to generate a stream of gas, typically a stream of air.

[0013] The air is first of all drawn by the impeller 2 through the bellmouth inlet 5 comprising a central passage 9, which means to say an opening via which the air drawn in by the impeller 2 passes, which is situated immediately downstream of the inlet opening of the volute.

[0014] The air is then discharged by the impeller 2 via a gas discharge duct 7 in the form of a centrifugal stream of air generated by the rotation of the impeller 2 as it is driven by the motor 1.

[0015] The discharge duct 7 is formed within a three-dimensional structure 3, 4 referred to as a “volute” comprising a volute lower part 3, commonly referred to as the lower volute, and a volute upper part 4 referred to as the upper volute, which connect together. <1ilename> 4 2014255597 19 Oct 2015 [0016] The volute lower and upper parts 3, 4 between them define an internal space or an internal compartment 10 encompassing the impeller 2, which means to say that the impeller 2 is sandwiched in the compartment 10 formed between the lower and upper volute parts 3, 4.

[0017] Moreover, the volute lower and upper parts 3, 4 are also shaped so as to define at least part of a discharge duct 7 used to convey the gas delivered by said impeller 2.

[0018] The structure forming the bellmouth inlet 5 is positioned on the upper part 4 of the volute 3, 4, which means to say that the bellmouth inlet 5 sits on top of the upper part 4 of the volute 3.

[0019] In general, empty internal spaces or dead volumes 6 lie between the wall of the volute upper part 4, which means to say the upper volute 4, and the wall of the bellmouth inlet 5.

[0020] In general, empty internal spaces or dead volumes 6 lie between the wall of the volute upper part 4, which means to say the upper volute 4, and the wall of the bellmouth inlet 5.

[0021] In other words, the space or the volume(s) 6 situated between the volute 3, 4 and the bellmouth 5, which are structures of three-dimensional shape, is left empty and constitutes or constitute one or more dead volumes.

[0022] According to the present invention, use is made of these dead volumes 6 to solve the problem of noise emissions, which means to say to attenuate the noise generated by the turbine as it is operating.

[0023] To do this, as figure 2 illustrates, according to the present invention the noise emissions are attenuated by inserting into all or part of said dead volumes 6, situated between the bellmouth 5 and the volute upper part 4, one (or more) soundproofing material(s) 11, also referred to as “acoustic core” material(s).

[0024] The addition of an acoustic core 11 into the dead space 6 allows the noise emissions generated by the high speed rotation of the impeller 2, typically at speeds of between 10 000 and 60 000 rpm, to be halted and/or absorbed as much as possible. C:\pot\word\SPEC-1039965.docx 5 2014255597 19 Oct 2015 [0025] A soundproofing material 11 that can be used is a flexible material either of elastomer type, for example silicone, rubber or thermoplastic elastomer, or a soft metal such as lead, or even an open-cell or closed-cell foam structure.

[0026] Moreover, sealing means 15 such as a gasket or the like allow a fluid tight seal to be created between the volute lower part 3 and the external wall of the motor 1 or a space containing the motor 1, so as to prevent air from getting in or out between these turbine components.

[0027] As can be seen in figures 1 and 2, the volute lower and upper parts 3, 4 which between them define the internal compartment 10 in which the impeller 2 is rotated to produce the stream of gas, particularly air, are formed of two three-dimensional structures that join together.

[0028] More specifically, the volute lower part 3 is in the overall shape of a cup, the bottom 13 of which has a central first opening 16 (cf. figure 2) that forms a sleeve around part of the wall or external cowling of the motor (cf. figure 1) or of a compartment containing the motor 1, when the volute lower part 3 is positioned around the said motor 1.

[0029] Moreover, the volute upper part 4 forms a sort of cover fitting over the volute lower part 3 as illustrated in figures 1 and 2.

[0030] It comprises a restriction 14 with a central second opening 17 facing the inlet opening 9 of the bellmouth inlet 5 so that air drawn in by the impeller 2 as it rotates passes in succession through the inlet opening 9 of the bellmouth then through the central second opening 17.

[0031] The profiles of the wall of the bellmouth 5 at the inlet opening 9 and of the wall of the volute upper part 4 at the restriction 14 are rounded so as to improve the fluidity of the circulation of gas, namely of the air drawn in.

[0032] The bellmouth inlet 5 preferably covers all of the volute upper part 4.

[0033] For preference, the bellmouth 5, the shaft 8 of the motor 1 and the volute lower and upper parts 3, 4 are arranged coaxially with respect to one another.

[0034] Typically, the volute lower and upper parts 3, 4 are made of thermoplastic, whereas the bellmouth 5 is preferably made of elastomer. C:\po1\word\SPEC-1039965.docx 6 2014255597 19 Oct 2015 [0035] The gas, such as air, accelerated by the impeller 2 is collected by a supply duct 7 which sends it to a breathing circuit connected to a patient.

[0036] A turbine according to the invention can be used to treat respiratory problems of all kinds, particularly sleep apnea, chronic obstructive pulmonary disease or COPD, problems associated with obesity, etc.

[0037] Typically, a turbine according to the invention is arranged in a respiratory assistance apparatus of CPAP (constant pressure) or BiPAP (two pressure levels) type.

Comparative example [0038] In order to verify the effectiveness at reducing noise pollution using a turbine according to the invention, comparative tests were carried out using turbines either equipped or not equipped with a soundproofing material in the dead volumes situated between the bellmouth inlet and the volute upper part of said turbines.

[0039] The acoustic spectrum was recorded 1 meter away from the turbines, laterally, normal to the air outlet (lateral measurement below), and from above, vertical to the air inlet (vertical measurement below).

[0040] Table A shows the variation in mean noise with an A-weighting (the Aeq) over 1 minute with respect to a turbine without an acoustic core (reference turbine outside of the invention) for a turbine speed of 1000 Hz.

Table A

Turbine Lateral measurement (dB A) Vertical measurement (dB A) Without core Reference noise level Reference noise level Silicone core -0.92 -0.31 Lead core -0.41 0.85 [0041] Table B is similar to Table A, for identical characteristics, but exclusively for noise emitted at the audible frequency of 6300 Hz. C:\po1\word\SPEC-1039965.docx 7

Table B

Turbine Lateral measurement (dB A) Vertical measurement (dB A) Without core Reference noise level Reference noise level Silicone core -1.38 -2.15 Lead core -1.37 -1.82 2014255597 19 Oct 2015 [0042] It may be noted that the solution of the invention, based on incorporating a soundproofing material into the dead volumes situated between the bellmouth inlet and the volute upper part, allows an effective attenuation of noise emissions generated by the motor and the impeller as the turbine is rotating.

[0043] Of the materials tested, the soundproofing material of elastomer type, namely a silicone, yielded the best results in terms of the effectiveness with which noise emissions were controlled, by comparison with the soft metal tested, in this instance here lead.

[0044] It is therefore preferable to use a soundproofing material of the elastomer type, notably a thermoplastic elastomer or TPE.

[0045] More generally, the present invention makes it possible to absorb audible frequencies in the frequency range extending from 20 to 20 000 Hz.

[0046] Where the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereto. C:\pof\word\SPEC-1039965.docx

Claims

The Claims defining the invention are as follows:

1. A turbine for a respiratory assistance apparatus, comprising : - an electric motor collaborating with an impeller to generate a stream of gas, - a bellmouth inlet comprising an inlet opening through which gas is drawn when the impeller is rotationally driven by the electric motor, the impeller being situated immediately downstream of the inlet opening, - a volute comprising a volute lower part and a volute upper part which are coupled to one another and shaped in such a way as to form an internal compartment encompassing the impeller and at least one part of a discharge duct used to carry the gas delivered by said impeller, and - the bellmouth inlet being arranged on the volute upper part while defining at least one dead volume between them, wherein at least one dead volume comprises at least one soundproofing material able to attenuate at least some of the noise emissions generated by the motor and/or the impeller when the impeller is rotating, the soundproofing material being an elastomeric material.
2. The turbine as claimed in claim 1, wherein the elastomeric material is silicone, rubber or thermoplastic elastomer.
3. The turbine as claimed in claim 1 or 2, wherein the motor allows the impeller to be driven at a speed of between 0 and 100 000 rpm.
4. The turbine as claimed in any one of claims 1 to 3 wherein the motor allows the impeller to be driven at a speed of between 10 000 and 60 000 rpm.
5. The turbine as claimed in any one of the preceding claims, wherein the volute lower part and the volute upper part are held together rigidly.
6. The turbine as claimed in any one of the preceding claims, wherein an acoustic core is trapped between the bellmouth and the volute upper part.
7. The turbine as claimed in any one of the preceding claims, wherein the bellmouth is made of elastomer.
8. The turbine as claimed in any one of the preceding claims, wherein sealing means allow a fluid tight seal to be created between the volute lower part and the external wall of the motor or of a space containing the motor.
9. The turbine as claimed in any one of the preceding claims, wherein the volute lower part and the volute upper part are made of a polymer material.
10. The turbine as claimed in claim 9, wherein the volute lower part and the volute upper part are made of a polycarbonate or ABS.
11. A respiratory assistance apparatus comprising a turbine as claimed in any one of the preceding claims.
12. The respiratory assistance apparatus as claimed in claim 11, wherein it is selected from apparatuses of the CPAP or BiPAP type.