HOUSEHOLD APPLIANCE WITH A BLOWER AND A FLOW CHANNEL

Abstract

A household appliance has a device housing, a blower arranged in the device housing, an outlet opening formed in the flow direction behind the blower in the device housing, and a flow channel. Soundwaves are generated by the blower, and produce resonances characterized by standing waves, which form between opposing inner walls of the flow channel. A sound reducing wall is positioned in the flow channel, the wall plane of which is oriented parallel to a primary flow direction of the air flow guided in the flow channel. The sound reducing wall is positioned in the flow channel so that a maximum for a fast amplitude of a sound particle velocity of the air flow guided in the flow channel lies in the wall plane of the sound reducing wall. The soundwaves form while interspersing the sound reducing wall between the opposing inner walls of the flow channel.

Claims

1. A household appliance comprising: a device housing, a blower arranged in the device housing, an outlet opening formed in a flow direction behind the blower in the device housing, and a flow channel, which connects the outlet opening with the blower in a stream-guiding manner, wherein the blower is configured to generate soundwaves within the flow channel that produce resonances characterized by standing waves between opposing inner walls of the flow channel, wherein a sound reducing wall is positioned in the flow channel, a wall plane of which is oriented parallel to a primary flow direction (s) of the air flow guided in the flow channel, wherein the sound reducing wall is positioned in the flow channel so that a maximum for a fast amplitude of a sound particle velocity of the air flow guided in the flow channel lies in a wall plane of the sound reducing wall, and wherein the soundwaves form between the opposing inner walls of the flow channel while interspersing the sound reducing wall between the opposing inner walls, such that the soundwaves propagate through the sound reducing wall.

2. The household appliance according to claim 1, wherein the household appliance is a floor processing device, in particular a cleaning device, with a suction opening and a suction material chamber arranged in a primary flow direction (s) between the suction opening and the blower.

3. The household appliance according to claim 1, wherein the sound reducing wall is positioned in the flow channel between the blower and the outlet opening.

4. The household appliance according to claim 1, wherein the sound reducing wall is centrally arranged in the flow channel in relation to an opening cross section of the flow channel.

5. The household appliance according to claim 4, wherein the flow channel is symmetrically designed in a cross section transverse to a longitudinal extension oriented in the primary flow direction (s), and the sound reducing wall runs through a symmetry center of the flow channel.

6. The household appliance according to claim 1, wherein an inner wall of the flow channel and the sound reducing wall are spaced apart from each other transverse to the primary flow direction (s) by a distance (a) corresponding to one fourth (λ/4) of a wavelength of a soundwave emitted by the blower.

7. The household appliance according to claim 1, wherein the sound reducing wall is comprised of a nonwoven material or foam material.

8. The household appliance according to claim 1, wherein the sound reducing wall has a wall thickness (d) of several millimeters.

9. The household appliance according to claim 1, wherein the sound reducing wall has a wall thickness (d) of between 1 mm and 10 mm.

10. The household appliance according to claim 9, wherein the wall thickness (d) is between 3 mm and 6 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other objects and features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

[0015] In the drawings,

[0016] FIG. 1 is a household appliance according to the invention;

[0017] FIG. 2 is a flow channel with a sound reducing wall; and

[0018] FIG. 3 is a schematic sketch of the function of the sound reducing wall.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0019] FIG. 1 initially shows a household appliance 1 in the form of a floor processing device, here for example as a vacuum cleaner manually guided by a user. The household appliance 1 has a handle 12, with which the user can guide the household appliance 1 over a surface to be cleaned, so as to vacuum suction material, i.e., dust and/or dirt, into a suction material chamber 8. The household appliance 1 has an electric motor-driven blower 3, which sucks the suction material into the suction material chamber 8 proceeding from a suction opening 7. A filter element 11 allocated to the suction material chamber 8 filters the suction material out of the sucked in air, so that only cleaned air flows on to the blower 3. Located in the flow direction behind the blower 3, i.e., on the pressure side of the blower 3, is a flow channel 5, which leads to an outlet opening. The outlet opening 4 is located on a wall of a device housing 2 of the household appliance 1. Proceeding from the blower 3 to the outlet opening 4, the flow channel 5 prescribes a primary flow direction s for the air flow guided in the flow channel 5. Instead of the embodiment only shown exemplarily here, the flow channel 5 can also have a deviating shape, for example a rectangular cross section instead of a round cross section. The flow channel 5 can also run straight instead of bent relative to the outlet opening 4. In addition, it is possible that the cross sectional shape of the flow channel 5 change in the direction of longitudinal extension.

[0020] A sound reducing wall 6 is arranged in the flow channel 5, and here for example consists of a fiber-reinforced nonwoven. For example, a wall thickness d of the sound reducing wall 6 here measures approx. 4 mm or below. In the exemplary embodiment here, the sound reducing wall 6 runs in the flow channel 5, completely from the blower 3 to the outlet opening 4. However, it is also possible that the sound reducing wall 6 only be formed over a portion of the length of the flow channel 5, and for example have a length of only a few centimeters. The sound reducing wall 6 especially preferably extends centrally within the flow channel 5, possibly even parallel to opposing inner walls 10 of a flow channel 5 with a rectangular cross section.

[0021] FIG. 2 shows a cross section of the flow channel 5 transverse to a longitudinal extension of the flow channel 5 in a primary flow direction s. As depicted, the sound reducing wall 6 is arranged centrally within the flow channel 5, which is here round, for example, specifically in such a way that the sound reducing wall 6 forms a symmetry plane of the cylindrically designed flow channel 5. An identical distance a to a respective partial area of an inner wall 10 of the flow channel 5 exists on both sides of the sound reducing wall 6. As already mentioned, shapes other than the cylindrical shape of the flow channel 5 shown here are also conceivable, for example an oval or rectangular cross sectional shape of the flow channel 5. It is essential that the sound reducing wall 6 is formed and arranged within the flow channel 5 in such a way that the sound reducing wall 6 runs parallel to the primary flow direction s within the flow channel 5 on the one hand, and is centrally arranged in the flow channel 5 on the other, specifically in such a way that the distances a to both sides of the sound reducing wall 6 are identical. Relative to its longitudinal extension, the flow channel 5 can also just sectionally have a sound reducing wall 6, or several sound reducing walls 6 one behind the other.

[0022] FIG. 3 shows a longitudinal section through a partial area of the flow channel 5. Exemplarily shown are two resonance modes with the wavelengths λ/2 and 3 λ/2. The distance a between the sound reducing wall 6 and the inner wall 10 of the flow channel 5 is dimensioned in such a way that its amount corresponds to one fourth of the wavelength of a base mode formed within the flow channel 5. The progression of the depicted oscillation modes of the resonance wave reflects the locally varying amplitudes of the sound energy of the resonance wave, i.e., a fast amplitude 9 of the sound particle velocity that runs transverse to the primary flow direction s of the air flow guided in the flow channel 5. As discernible on FIG. 3, the sound particle velocity, and hence also the sound energy, has a maximum in the geometric center of the flow channel 5, where the distance a to the adjacent inner wall 10 is identical on both sides of the sound reducing wall 6. According to the invention, the sound reducing wall 6 is placed precisely in this plane, which is characterized by the maximum of the fast amplitude 9, so as to there absorb the sound energy by means of the nonwoven material 24. In the area of the inner wall 10 of the flow channel 5, the fast amplitude 9 or the sound energy is essentially equal to zero, so that it would not be required or effective to place a sound absorption material there. The standing wave can propagate transverse to the sound reducing wall 6 unimpeded, i.e., as reflection-free as possible, due to the sound-permeable property of the material of the sound reducing wall 6. As a whole, the sound energy of the resonance wave formed in the flow channel 5 is thus effectively reduced, wherein the air flow can simultaneously flow through the flow channel 5 in the direction of the outlet opening 4 with as little loss in pressure as possible in the primary flow direction s. For example, the efficiency of the sound reducing wall 6, i.e., the sound reduction in relation to a pressure loss within the flow channel 5, measures 2:1 or above, which by comparison with prior art means a distinctly higher efficiency.

[0023] Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

REFERENCE LIST

[0024]

TABLE-US-00001 1 Household appliance 2 Device housing 3 Blower 4 Outlet opening 5 Flow channel 6 Sound reducing wall 7 Suction opening 8 Suction material chamber 9 Fast amplitude 10 Inner wall 11 Filter element 12 Handle a Distance d Wall thickness s Primary flow direction