Patent Application
20120301267
The field of the invention relates to delivering units for therapeutic apparatus for splinting the upper respiratory tract, and to delivering methods performed by these therapeutic apparatus. More specifically, the invention relates to delivering units and delivering methods for TNI-apparatus.
TNI-apparatus are known, for example, from WO 02/062413 A2, in which they are referred to as anti-snoring apparatus. Such anti-snoring apparatus effect a splinting of the upper respiratory tract by administering air into the nose of a user via a conventional or modified oxygen cannula. Thus, the pressure in the respiratory tract is increased by some mbar above the ambient pressure. TNI-apparatus refer to apparatus which are suited for transnasal inspiration.
The CPAP-therapy (continuous positive airway pressure) works similarly, whereby nose or face masks are used to administer the air at a pressure of around 5 mbar and at a maximum pressure of 30 mbar. As the masks are pressed against the face during the night, i.e. over a long period of time, by exerting a certain pressure, skin irritations may occur and, as a result, problems may arise in the acceptance by the patient.
Moreover, evaporators, specifically respiratory humidifiers, are known. In combination with the present invention, the evaporator known from WO 2006/012877 can be used particularly advantageously.
In CPAP-apparatus, frequently radial blowers for delivering air are applied, which are well suited for the small pressures of below 30 mbar, typically 5 mbar, and high flows of up to 150 l/min. Due to the smaller tube diameters and, as a result thereof, the higher pressures of 150 mbar at the inlet of the nasal cannula, side channel compressors are suited better for TNI-apparatus. However, the problem about side channel compressors is the high noise development both at the inlet and the outlet. In addition, cooling ribs of the side channel compressor housing may be caused to vibrate due to the high periodic fluctuations in the interior of the side channel compressor, thereby emitting noise. Finally, the cooling of the side channel compressor must be considered with care, because the efficiency of a side channel compressor is typically lower than that of radial blowers, and also because the generation of higher pressures of 150 mbar requires more power while the rate is the same.
Although the noise development of radial blowers is very moderate as compared to side channel compressors, noise-insulation boxes are used in CPAP-apparatus, which lower the noise emission of CPAP-apparatus to the range of 30 dBA. In order to prevent the noise from being conducted through the air channels to the outside or into the respiratory tube, bypasses are installed in the noise-insulation box. This works according to the principle that an airflow can be diverted, while the noise cannot, which is clearly attenuated with each diversion. The standard is two to three bypasses, as each bypass increases the pressure loss coefficient.
A blower unit is known from WO 2004/046556 A2, which reduces the noise development in the blower unit, inter alia, by grids.
It is the object of the invention to provide a delivering unit and a delivering method, which allow for an acceptable noise emission.
This object is achieved with the teaching of the independent claims.
Preferred embodiments of the invention are defined in the dependent claims.
In a surprisingly advantageous manner, flexible connecting tubes between a pre noise absorber and a compressor and the post noise absorber and the pre noise absorber can provide both the conduction of air and the mechanical support of the pre noise absorber and the compressor, whereby the transmission of structure-borne noise is kept small.
Advantageously, a pressure-tight closure of the noise-insulation housing does not allow any direct noise to escape to the outside.
Below, a preferred embodiment of the invention will be explained in more detail by means of the accompanying drawings. In the drawings:
The lower end of the first inlet tube 15 is fitted onto a T-piece 16. From the T-piece 16, a second inlet tube 17 leads to an inlet connection piece 19, which leads into the inlet opening 27 of the noise box housing 20. A sealing ring made of an elastic material, e.g. silicone, serves to enclose the inlet connection piece 19 in the inlet opening 27. Moreover, an inlet λ/4-tube 18 is connected to the T-piece 16, the end of which is sealed with a plug. A tube sealed at one end can be called a blind tube. The side channel compressor 101 generates a tonal sound at about 200 Hz, whereby the center frequency of this sound emission depends on the rotational speed of the side channel compressor 101, which, again, depends on the required airflow, so that the center frequency fluctuates by about 200 Hz. The three tubes 15, 17 and 18 define a notch filter, which suppresses sound frequencies by 200 Hz or at least strongly attenuates them. The length of the first inlet tube 15 is 320 mm. The length of the inlet λ/4-tube 18 is 450 mm and the length of the second inlet tube 17 is 300 mm.
On the blow-out opening of the noise box housing 20 a short blow-out connection piece 12 with a sound absorber connection 14 is provided, onto which a blow-out sound absorber 13 is pushed. The blow-out sound absorber 13 is formed of a blind tube having a length of 500 mm, which is rolled up between a backside 21 of the noise box housing 20 and the corresponding wall of the housing hood 3. All tubes have an inner diameter of 8 mm. Like a notch filter, the blow-out sound absorber 13 likewise acts at 200 Hz. As a nasal cannula is connected via a humidifier to the blow-out connection piece, with the nasal cannula strongly attenuating the sound, the noise absorption on the blow-out side is much less critical as on the inlet side. However, it was observed that the lid of the humidifier known from WO 2006/012877 A1 can be resonantly excited by tonal sound. This can be most efficiently suppressed by the blow-out sound absorber 13, which is adjusted to the resonance of the lid of the humidifier.
At the moment it is unclear, how sharp the resonance of the lid of the humidifier is. Therefore, in another embodiment, also the blow-out sound absorber may be adjusted to the sound emission of the side channel compressor 101 of about 200 Hz.
In other embodiments, also more complicated embodiments of resonant inlet sound absorbers can be used, wherein several inlet λ/4-tubes connect T-pieces, to which λ/4-blind tubes are connected, whereby each pair of tubes, i.e. the tube extending from a T-piece and the blind tube connected to the T-piece, is adjusted to a different sound wavelength and, thus, sound frequency, that is, for example, 180 Hz, 200 Hz and 220 Hz, so as to favorably attenuate the range of 170 Hz to 220 Hz by three notches. Thus, a good attenuation can also be achieved at different delivering rates and at the different compressor speeds resulting therefrom. Such multi-stage sound absorbers can also be used on the blow-out side.
Furthermore, it has been found that, given the great pressure difference between inlet and outlet of 150 mbar (CPAP-apparatus: 100 l/min, about 15 mbar), the typical airflow of 10 to 50 l/min in a TNI-apparatus is not enough to sufficiently cool the TNI-apparatus. Therefore, the outer blowers 7 arrange for an airflow from venting slots 26 in the housing bottom 2 through the outer heat sink 41 past the blower tower 6 through the outer blowers 7 through a power supply unit 8 to the venting slots 34 in the housing hood 3. For noise-protection reasons, the lower edge of the blower tower 6 is bent away from the outer heat sink 41 over the total width. The bent-away part 30 has a height of approximately 1 cm.
To insulate it against the transmission of structure-borne noise, the noise box housing 20 stands on rubber-metal buffers 23 in corresponding recesses in the housing bottom 2.
In addition, the power supply unit 8 is insulated against the noise box housing 20 by an insulating foil 9 made of Macrolon. The printed circuit board 10, too, is insulated against the noise box housing 20 by such an insulating foil 11. To communicate with the outside world the printed circuit board 10 is provided with a sub-D-socket, which is accessible from outside through a recess 29 in the housing bottom 2. In the opening 25 an apparatus connector 28 is mounted.
To allow a better orientation, the left side 22 of the noise box housing 20 is shown, with the outer heat sink 41 forming the front side.
To permit a further noise absorption, a mass element 131, silicone foam buffers 132 having a thickness of 3 mm, a mass rear wall 133 and an absorber element 134 as well as an absorber rear wall 135 are provided. The mass element 131 is formed of a steel sheet ST37, which is bent in a U-shaped manner and has a thickness of 1.5 mm and which shields the upper side and the major part of the left and right inner side of the noise box housing 20. The mass rear wall is likewise made of a steel sheet ST37 having a thickness of 1.5 mm and internally shields the backside 21. The vibrations of the steel sheets caused by the noise are internally attenuated by the absorber element 134 and the absorber rear wall 135 and externally by the silicone foam buffers 132. The absorber element 134 and the absorber rear wall 135 are made of neoprene having a thickness of 6 mm. Neoprene is thermally more stable, but less bio-compatible than noise-insulation foam. The absorber element 134 and the absorber rear wall 135 absorb the noise before it hits the mass element 131 and the mass rear wall 133. The mass element 131 rests on supports 64, which are made of 2 mm of silicone foam, on a housing shell 61 of the post noise absorber 60. The side parts of the mass element 131 do, therefore, not extend to the bottom side of the noise box housing 20.
To avoid the transmission of structure-borne noise, the side channel compressor 101, the pre noise absorber 80 and the post noise absorber 60 are not directly connected to each other, but the side channel compressor 101 is connected to the pre noise absorber 80 by the two tubes 96 and the spacers 95. The post noise absorber 60 is loosely connected to the pre noise absorber 80 by a tube 71, by another covered tube and by a spacer 72. Only if the apparatus is turned over to one side, or in the event of impacts against the apparatus, e.g. during transport, it must be ensured by limit stops that the side channel compressor 101 and the pre noise absorber 80 are not displaced out of their specified position. No problems will arise, however, if the side channel compressor 101 hits against the absorber element 134 and the absorber rear wall 135. An impact protection 47, which is illustrated in
Also the blocks 85 having a neoprene layer 86 serve as limit stops, for example, if the TNI-apparatus is put down roughly. Normally, however, an air gap having a width of 1-2 mm is provided between the lower edges of the heat sink of the side channel compressor 101 and a neoprene layer 86 so as to avoid a transmission of structure-borne noise. Similarly, this refers to the impact protection 65 which, like the supports 64, is made of a silicone foam of 2 mm thickness. Normally, an air gap having a width of 1-2 mm is also provided between the impact protection 65 and the lower side of the pre noise absorber 80. Also between the upper side of the side channel compressor 101 and the absorber element 134 an air gap having a width of 1-2 mm is normally provided.
A seal 63 made of silicone foam having a thickness of 3 mm forms the lower side of the post noise absorber 60. The seal 63 projects over the housing shell 61. During the assembly, the projecting parts are folded upwardly to the sides of the housing shell 61, so that the blow-out openings in the housing shell 61 and in the seal 63, 69 and 70 are in alignment. In the mounted condition, the seal 63 is pressed together between the lower side of the noise box housing 20 and the housing shell 61.
As was mentioned above, there is a pressure difference of approximately 150 mbar between the inlet side and the outlet side, so that in particular the blow-out side has to be sealed with respect to the inlet side and also with respect to the ambient pressure. Approximately the upper half (shown at the bottom of
Air conduction seals 87-90 made of noise-absorbing foam as well as blocks 85 having neoprene layers 86 are glued onto the upper housing shell 84. As was mentioned above, the blocks 85 serve as an impact protection. The air conduction seals 87-90 serve to concentrate the forced convection generated by the heat sink unit 40 to the cooling plates.
On the inner side of the outer heat sink 41 a recess 54 is sinked as well, into which four inner heat sinks 42 are mounted. However, only one inner heat sink 42 is illustrated in all relevant
The edgewise affixed noise-absorbing foam pieces 43 to 46 are mechanically not stable enough to hold the side channel compressor 101. This is accomplished by the impact protection 47, which is made of a polycarbonate block with a neoprene layer of a thickness of 2 mm.
Although TNI-apparatus are usually used to deliver and administer ambient air, other gases can be delivered as well. Also, medicine, e.g. in the form of aerosols, or anesthetic gases may be added to the delivered gas.
Above, the invention was explained in more detail by means of preferred embodiments. A person skilled in the art will appreciate, however, that various alterations and modifications may be made without departing from the spirit of the invention. Therefore, the scope of protection will be defined by the accompanying claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 024 839.2 | May 2006 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE2007/000799 | 5/3/2007 | WO | 00 | 8/22/2011 |
