当前申请(专利权)人地址：
Tetbury Hill, Malmesbury, Wiltshire, SN16 0RP, United Kingdom
摘要：
A noise attenuator 120, such as a noise damping resonator for a vacuum cleaner, comprises an inner element having an axially extending inner wall 122 that encloses a hollow interior, at least a portion of the inner wall being perforated. An outer wall extends around the inner wall to enclose the perforated portion and to define a cavity 138 there around. A transverse width of the outer wall varies axially. The width of the outer wall may vary non-linearly and may comprise tubular portions 140, 142, 144 of varying diameters. Adjacent tubular portions of the outer wall may be connected by radially extending planar portions of the outer wall. The outer wall may comprise a curved portion that curves in a longitudinal plane and extends between tubular or frustoconical portions of the outer wall. At least a portion of the outer wall may have an undulating or square-wave profile in a longitudinal plane. The inner element may be open at each axial end or may comprise an end wall that closes an axial end thereof.
权利要求：
Claims
1. A noise attenuator, comprising:
an inner element that comprises an axially-extending inner wall that
encloses a hollow interior, at least a portion of the inner wall being perforated; and
an outer wall extending around the inner wall to enclose the perforated
portion of the inner wall and to define a cavity surrounding the perforated portion
of the inner wall, wherein a transverse width of the outer wall varies axially. 2. The noise attenuator of claim 1, wherein the width of the outer wall varies non-
linearly.
3. The noise attenuator of claim 1 or claim 2, wherein at least one portion of the outer
wall is tubular.
4. The noise attenuator of claim 3, wherein the outer wall comprises a non-tubular
portion disposed between axially-spaced tubular portions.
5. The noise attenuator of claim 3 or claim 4, wherein the outer wall comprises tubular
portions of varying diameters.
6. The noise attenuator of claim 5, wherein adjacent tubular portions of the outer wall
are connected by radially-extending planar portions of the outer wall. 7. The noise attenuator of any of claims 3 to 6, wherein the outer wall comprises a
curved portion that curves in a longitudinal plane, the curved portion extending
between tubular or frustoconical portions of the outer wall.
8. The noise attenuator of any preceding claim, wherein at least a portion of the outer
wall has an undulating or square-wave profile in a longitudinal plane.
9. The noise attenuator of any preceding claim, comprising a plane of symmetry that
is orthogonal to a central axis of the inner element.
10. The noise attenuator of claim 9, wherein the plane of symmetry intersects an axial
midpoint of the inner element.
11. The noise attenuator of any preceding claim, wherein the outer wall connects to
the inner wall through axially-spaced end walls that extend transversely between
the inner wall and the outer wall
12. The noise attenuator of claim 11, wherein the outer wall and the end walls
collectively define an impermeable outer shell that encloses the cavity.
13. The noise attenuator of any of claims 1 to 10, wherein the outer wall connects
directly to the inner wall to define an impermeable outer shell that encloses the
cavity.
14. The noise attenuator of any preceding claim, wherein the inner wall is tubular.
15. The noise attenuator of any preceding claim, wherein the outer wall has circular
symmetry around a central axis of the inner element.
16. The noise attenuator of any preceding claim, wherein the inner element is
arranged concentrically with the outer wall.
17. The noise attenuator of any preceding claim, wherein the inner element is open at
each axial end.
18. The noise attenuator of any of claims 1 to 16, wherein the inner element comprises
an end wall that closes an axial end of the inner element.
19. The noise attenuator of any preceding claim, wherein the cavity and perforations
of the perforated portion of the inner wall together define a noise-damping
resonator.
20. The noise attenuator of any preceding claim, wherein the perforated portion of the
inner wall comprises no perforations having a width of more than 1mm. 21. The noise attenuator of any preceding claim, wherein the perforated portion of the
inner wall comprises no perforations having a width of less than 0.5mm. 22. The noise attenuator of any preceding claim, wherein the perforated portion of the
inner wall has a perforation ratio of between 1% and 5%.
23. The noise attenuator of any preceding claim, comprising one or more partition
walls extending transversely within the cavity between the inner element and the
outer wall, to partition the cavity into sub-cavities.
24. The noise attenuator of claim 23, wherein the sub-cavities are mutually isolated. 25. A device comprising the noise attenuator of any preceding claim.