U.S. patent application number 13/547736 was filed with the patent office on 2013-01-17 for fan.
This patent application is currently assigned to Dyson Technology Limited. The applicant listed for this patent is Mark James Adkin, Neil Andrew Stewart, David Andrew Tibbetts. Invention is credited to Mark James Adkin, Neil Andrew Stewart, David Andrew Tibbetts.
Application Number | 20130017104 13/547736 |
Document ID | / |
Family ID | 44586684 |
Filed Date | 2013-01-17 |
United States Patent
Application |
20130017104 |
Kind Code |
A1 |
Stewart; Neil Andrew ; et
al. |
January 17, 2013 |
FAN
Abstract
A fan assembly for generating an air flow within a room includes
an annular casing which defines an interior passage. The interior
passage includes an air inlet, and houses, downstream from the air
inlet, an impeller and a motor for driving the impeller to draw an
air flow through the air inlet and into the fan assembly. The
interior passage also has an air outlet from which at least a
portion of the air flow is emitted from the fan assembly. The
annular casing defines a bore about which the interior passage
extends and through which a secondary air flow from outside the fan
assembly is drawn by the air emitted from the air outlet.
Inventors: |
Stewart; Neil Andrew;
(Malmesbury, GB) ; Adkin; Mark James; (Malmesbury,
GB) ; Tibbetts; David Andrew; (Malmesbury,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stewart; Neil Andrew
Adkin; Mark James
Tibbetts; David Andrew |
Malmesbury
Malmesbury
Malmesbury |
|
GB
GB
GB |
|
|
Assignee: |
Dyson Technology Limited
Malmesbury
GB
|
Family ID: |
44586684 |
Appl. No.: |
13/547736 |
Filed: |
July 12, 2012 |
Current U.S.
Class: |
417/423.14 ;
415/203; 415/226; 417/423.15 |
Current CPC
Class: |
F04D 25/088 20130101;
F04F 5/16 20130101; F04D 25/08 20130101 |
Class at
Publication: |
417/423.14 ;
417/423.15; 415/226; 415/203 |
International
Class: |
F04D 13/06 20060101
F04D013/06; F04D 29/42 20060101 F04D029/42 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2011 |
GB |
1112215.7 |
Claims
1. A fan assembly for generating an air flow within a room, the fan
assembly comprising an annular casing defining an interior passage
with at least one air inlet, the interior passage housing,
downstream from said at least one air inlet, an impeller and a
motor for driving the impeller to draw an air flow through said at
least one air inlet and into the fan assembly, the interior passage
also having at least one air outlet from which at least a portion
of the air flow is emitted from the fan assembly, the casing
defining a bore about which the interior passage extends and
through which a secondary air flow from outside the fan assembly is
drawn by the air emitted from said at least one air outlet.
2. The fan assembly of claim 1, wherein the interior passage
comprises an inlet section comprising said at least one air inlet,
and an outlet section located downstream from the inlet section and
comprising said at least one air outlet.
3. The fan assembly of claim 2, wherein the inlet section extends
about at least part of the outlet section.
4. The fan assembly of claim 2, wherein the outlet section has a
cross-section which varies continuously about the bore.
5. The fan assembly of claim 2, wherein the outlet section is
continuous.
6. The fan assembly of claim 2, wherein the outlet section has a
generally rectangular cross-section.
7. The fan assembly of claim 2, wherein the impeller and the motor
are located within the inlet section.
8. The fan assembly of claim 7, wherein the inlet section comprises
an impeller housing section which houses the impeller and the
motor, and a conduit section extending from said at least one air
inlet to the impeller housing section.
9. The fan assembly of claim 8, wherein the conduit section extends
about the outlet section.
10. The fan assembly of claim 8, wherein the conduit section is
arcuate in shape.
11. The fan assembly of claim 8, wherein said at least one air
inlet comprises an air inlet located at one end of the conduit
section.
12. The fan assembly of claim 1, wherein the impeller is rotatable
about an impeller axis, and the bore has a bore axis, and wherein
the bore axis is substantially orthogonal to the impeller axis.
13. The fan assembly of claim 1, wherein the impeller is one of an
axial flow impeller and a mixed flow impeller.
14. The fan assembly of claim 1, comprising a diffuser located
downstream from the impeller.
15. The fan assembly of claim 1, wherein the casing comprises a
first annular side wall defining the bore, a second side wall
extending about the first side wall, an upper wall extending
between the side walls and a lower wall located opposite to the
upper wall.
16. The fan assembly of claim 15, wherein said at least one air
outlet is located between the lower wall and the first side
wall.
17. The fan assembly of claim 1, wherein said at least one air
outlet comprises a circular slot.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of United Kingdom
Application No. 1112215.7, filed Jul. 15, 2011, the entire contents
of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a fan assembly for
generating an air flow within a room. In its preferred embodiment,
the present invention relates to a ceiling fan.
BACKGROUND OF THE INVENTION
[0003] A number of ceiling fans are known. A standard ceiling fan
comprises a set of blades mounted about a first axis and a drive
also mounted about the first axis for rotating the set of
blades.
SUMMARY OF THE INVENTION
[0004] In a first aspect, the present invention provides a fan
assembly for generating an air flow within a room, the fan assembly
comprising an annular casing defining an interior passage with at
least one air inlet, the interior passage housing, downstream from
said at least one air inlet, an impeller and a motor for driving
the impeller to draw an air flow through said at least one air
inlet and into the fan assembly, the interior passage also having
at least one air outlet from which at least a portion of the air
flow is emitted from the fan assembly, the casing defining a bore
about which the interior passage extends and through which air from
outside the fan assembly is drawn by the air emitted from said at
least one air outlet.
[0005] The air emitted from the annular casing, referred to
subsequently as a primary air flow, entrains air surrounding the
casing, and so the fan assembly acts as an air amplifier to supply
both the primary air flow and the entrained air to the user. The
entrained air will be referred to subsequently as a secondary air
flow. The secondary air flow is drawn from the room space, region
or external environment surrounding the casing. The primary air
flow combines with the entrained secondary air flow to form a
combined, or total, air flow projected forward from the casing.
[0006] To provide the fan assembly with a compact appearance, the
impeller and the motor for driving the impeller are located within
the interior passage of the annular casing. Furthermore, by
locating the motor and the impeller within the interior passage,
abrupt changes in the direction of the air flow between the
impeller and the portion of the interior passage containing the air
outlet(s) can be minimized, thereby reducing the loss of energy in
the air flow as it passes into this portion of the interior passage
and so increasing the efficiency of the air flow passing from the
impeller to the air outlet(s).
[0007] The casing preferably comprises a first annular side wall
defining the bore, a second side wall extending about the first
side wall, an upper wall and a lower wall. The air outlet(s) may be
located between the lower wall and the first side wall, or in the
lower wall. The air outlet(s) are preferably configured to emit the
primary air flow away from the axis of the bore, preferably in the
shape of an outwardly tapering cone.
[0008] We have found that the emission of the primary air flow from
the casing in a direction which extends away from the bore axis can
increase the degree of the entrainment of the secondary air flow by
the primary air flow, and thus increase the flow rate of the
combined air flow generated by the fan assembly. References herein
to absolute or relative values of the flow rate, or the maximum
velocity, of the combined air flow are made in respect of those
values as recorded at a distance of three times the diameter of the
air outlet of the casing.
[0009] Without wishing to be bound by any theory, we consider that
the rate of entrainment of the secondary air flow by the primary
air flow may be related to the magnitude of the surface area of the
outer profile of the primary air flow emitted from the casing. When
the primary air flow is outwardly tapering, or flared, the surface
area of the outer profile is relatively high, promoting mixing of
the primary air flow and the air surrounding the casing and thus
increasing the flow rate of the combined air flow. Increasing the
flow rate of the combined air flow generated by the casing has the
effect of decreasing the maximum velocity of the combined air flow.
This can make the fan assembly suitable for use as a ceiling fan
for generating a flow of air through a room or an office.
[0010] The first side wall preferably comprises a section adjacent
the lower wall which extends towards the lower wall in a direction
which tapers away from the bore axis. An angle of inclination of
the section of the side wall to the bore axis may be between 0 and
45.degree.. This section of the side wall preferably has a shape
which is substantially frusto-conical. The air outlet(s) may be
arranged to emit the primary air flow in a direction which is
substantially parallel to this section of the side wall. This
section of the side wall may define with the lower end wall the air
outlet(s) of the casing. This section of the side wall may be
integral with part of the lower wall.
[0011] The air outlet(s) preferably extend about the bore axis. The
casing may comprise a plurality of air outlets angularly spaced
about the bore axis, but in a preferred embodiment the casing
comprises a circular air outlet, with the bore axis passing through
the center of the air outlet. A portion of the interior passage
which is located adjacent the air outlet may be shaped to direct
the primary air flow through the air outlet so that the primary air
flow is directed away from the bore axis.
[0012] The, or each, air inlet of the casing is preferably
substantially orthogonal to the air outlet of the casing. The
interior passage may comprise an inlet section comprising the air
inlet(s), and an outlet section located downstream from the inlet
section and comprising the air outlet(s). The inlet section
preferably extends about at least part of the outlet section to
maintain the annular shape of the casing; depending on the extent
of the overlap between the inlet section and the outlet section,
the casing may have a coiled shape extending about the bore of the
casing.
[0013] The outlet section of the interior passage preferably
extends about the bore. The cross-sectional profile of the outlet
section preferably varies about the bore. As the air flow passes
through the outlet section, the flow rate of the air flow remaining
within the outlet section decreases about the bore as air is
emitted from the casing. In order to maintain a substantially
constant air flow velocity within the outlet section, the
cross-sectional area of the outlet section preferably decreases in
a direction extending from the inlet section. By maintaining a
substantially constant air flow velocity within the outlet section,
the velocity at which the primary air flow is emitted from the
outlet section may be substantially constant about the bore, with
the result that the velocity of the combined air flow generated by
the fan assembly can be substantially even about the bore axis.
[0014] The outlet section may have a generally rectangular
cross-section. The variation in the cross-section area of the
outlet section may be effected in one of a number of different
ways. For example, the distance between the upper wall and the
lower wall may vary about the bore. Alternatively, or additionally,
the distance between the first side wall and the second side wall
may vary about the bore; this latter alternative is preferred as it
allows the outlet section to have a uniform height about the
bore.
[0015] The outlet section is preferably continuous. Where the
cross-sectional area of the outlet section varies about the bore,
the outlet section is preferably in the form of a scroll section,
having a cross-sectional area that decreases from a scroll inlet
section to a scroll outlet section. The scroll inlet section
preferably comprises an inlet port for receiving the air flow, and
the scroll outlet section comprising an outlet port for returning a
portion of the air flow to the scroll inlet section. This can
further assist in maintaining a constant primary air flow velocity
about the bore.
[0016] In a second aspect the present invention provides a fan
assembly for generating an air flow within a room, the fan assembly
comprising an impeller and a motor for driving the impeller to draw
an air flow into the fan assembly, and a casing having an interior
passage comprising a scroll section having a cross-sectional area
that decreases from a scroll inlet section to a scroll outlet
section, the scroll inlet section comprising an inlet port for
receiving the air flow and the scroll outlet section comprising an
outlet port for returning a first portion of the air flow to the
scroll inlet section, the scroll section having at least one air
outlet for emitting a second portion of the air flow from the
casing, the casing defining a bore through which air from outside
the fan assembly is drawn by the air emitted from said at least one
air outlet.
[0017] The outlet port is preferably located adjacent to the inlet
port. The inlet port and the outlet port are preferably
substantially co-planar so that the direction in which the first
portion of the air flow re-enters the scroll inlet section is
substantially the same as the direction in which the air flow
enters the scroll inlet section.
[0018] The impeller and the motor are preferably located within the
inlet section. The impeller and the motor may be located at any
desired position within the inlet section. The inlet section
preferably comprises an impeller housing section which houses the
impeller and the motor. The impeller housing section is preferably
located adjacent to the outlet section of the interior passage, and
is preferably located radially outside the outlet section so as to
extend about the bore, and preferably so that the axis of the
impeller does not intersect the bore of the casing. The impeller
housing section may have a different cross-section to the outlet
section of the casing, and so the interior passage may comprise an
intermediate section of varying cross-section which connects the
impeller housing section to the outlet section. The impeller
housing section may have a generally circular cross-section, and so
the cross-section of the intermediate section may vary from a
generally circular cross-section at one end thereof to a generally
rectangular cross-section at the other end thereof.
[0019] The interior passage preferably comprises a conduit section
extending from the air inlet(s) to the impeller housing section.
The conduit section may extend about at least part of the outlet
section to maintain the annular shape of the casing, and so may be
arcuate in shape.
[0020] The air inlet section may comprise a single air inlet, or a
plurality of air inlets through which the air flow is drawn into
the air inlet section. An air inlet is preferably located at one
end of the conduit section. This air inlet is preferably a
tangential air inlet for admitting the air flow into the fan
assembly in a direction which is substantially tangential to the
bore of the casing. This allows the air flow to enter the interior
passage of the casing without any sharp changes in the direction of
the air flow.
[0021] In a third aspect, the present invention provides a fan
assembly for generating an air flow within a room, the fan assembly
comprising an impeller and a motor for driving the impeller to draw
an air flow into the fan assembly, and a casing comprising a
continuous interior passage having a tangential air inlet through
which the air flow enters the interior passage, and at least one
air outlet for emitting at least a portion of the air flow, the
casing defining a bore about which the interior passage extends and
through which air from outside the fan assembly is drawn by the air
emitted from said at least one air outlet.
[0022] The impeller is rotatable about an impeller axis, and the
bore has a bore axis which is preferably substantially orthogonal
to the impeller axis. To minimize the size of the inlet section,
the impeller is preferably an axial flow impeller, but the impeller
may be a mixed flow impeller. The inlet section preferably
comprises a diffuser located downstream from the impeller for
guiding the air flow towards the outlet section of the casing.
[0023] The fan assembly preferably includes a support assembly for
supporting the casing on a ceiling of a room. The support assembly
preferably comprises a mounting plate which is attachable to the
ceiling of the room. The impeller axis is preferably at an angle of
less than 90.degree. to the mounting plate. The impeller axis is
more preferably at an angle of less than 45.degree. to the mounting
plate, and may be at an angle which is substantially parallel to
the mounting plate. As mentioned above, the bore axis is preferably
substantially orthogonal to the impeller axis, and this can allow
the fan assembly to have a relatively shallow profile when the
impeller axis is substantially parallel to the mounting plate, and
thus substantially parallel to a horizontal ceiling to which the
mounting plate is attached. The casing may be located relatively
close to the ceiling, reducing the risk of a user, or an item being
carried by the user, coming into contact with the casing.
[0024] The impeller housing section preferably comprises an outer
casing, a shroud extending about the motor and the impeller, and a
mounting arrangement for mounting the shroud within the outer
casing. Each of the shroud and the outer casing may be
substantially cylindrical. The mounting arrangement may comprise a
plurality of mounts located between the outer casing and the
shroud, and a plurality of resilient elements connected between the
mounts and shroud. In addition to positioning the shroud relative
to the outer casing, preferably so that the shroud is substantially
co-axial with the outer casing, the resilient elements can absorb
vibrations generated during use of the fan assembly. The resilient
elements are preferably held in a state of tension between the
mounts and the shroud, and preferably comprise a plurality of
tension springs each connected at one end to the shroud and at
another end to one of the supports. Means may be provided for
urging apart the ends of the tension springs in order to maintain
the springs in a state of tension. For example, the mounting
arrangement may comprise a spacer ring which is located between the
mounts for urging apart the mounts, and thereby urging one end of
each spring away from the other end.
[0025] The support assembly may be connected to the inlet section
or the outlet section of the fan assembly. For example, one end of
the inlet section may be connected to the support assembly.
Alternatively, the support assembly may be connected to part of the
inlet section located between the air inlet of the inlet section
and the impeller housing section.
[0026] The casing is preferably rotatable relative to the support
assembly to allow a user to change the direction in which the
primary air flow is emitted into a room. The casing is preferably
rotatable relative to the support assembly about a rotational axis
and between a first orientation in which the primary air flow is
directed away from the ceiling and a second orientation in which
the primary air flow is directed towards the ceiling. For example,
during the summer the user may wish to orient the casing so that
the primary air flow is emitted away from a ceiling to which the
fan assembly is attached and into a room so that the air flow
generated by the fan assembly provides a relatively cool breeze for
cooling a user located beneath the fan assembly. During the winter
however, the user may wish to invert the casing through 180.degree.
so that the primary air flow is emitted towards the ceiling to
displace and circulate warm air which has risen to the upper
portions of the walls of the room, without creating a breeze
directly beneath the fan assembly.
[0027] The casing may be inverted as it is rotated between the
first orientation and the second orientation. The rotational axis
of the casing is preferably substantially orthogonal to the bore
axis, and is preferably substantially co-planar with the impeller
axis.
[0028] The support assembly preferably comprises a ceiling mount
for mounting the fan assembly on a ceiling, an arm having a first
end connected to the ceiling mount, and a connector connecting a
second end of the arm to the casing.
[0029] Features described above in connection with the first aspect
of the invention are equally applicable to any of the second and
thirds aspects of the invention, and vice versa.
[0030] Preferred features of the invention will now be described,
by way of example only, with reference to the accompanying
drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a front perspective view, from above, of a first
example of a ceiling fan;
[0032] FIG. 2 is a left side view of the ceiling fan of FIG. 1
mounted to a ceiling, and with an annular nozzle of the ceiling fan
in a raised position;
[0033] FIG. 3 is a front view of the ceiling fan of FIG. 1;
[0034] FIG. 4 is a rear view of the ceiling fan of FIG. 1;
[0035] FIG. 5 is a top view of the ceiling fan of FIG. 1;
[0036] FIG. 6 is a side sectional view of the ceiling fan of FIG.
1, taken along line A-A in FIG. 5;
[0037] FIG. 7 is a close up view of area A indicated in FIG. 6,
illustrating the motor and impeller of an air inlet section of the
ceiling fan of FIG. 1;
[0038] FIG. 8 is a close up view of area B indicated in FIG. 6,
illustrating the air outlet of the annular nozzle;
[0039] FIG. 9 is a close up view of area D indicated in FIG. 6,
illustrating the connection between a ceiling mount and an arm of a
support assembly of the ceiling fan of FIG. 1;
[0040] FIG. 10 is a side sectional view of the ceiling mount and
the arm of the support assembly, taken along line C-C in FIG.
6;
[0041] FIG. 11 is a close up view of area C indicated in FIG. 6,
illustrating a releasable locking mechanism for retaining the
annular nozzle in the raised position;
[0042] FIG. 12 is a sectional view of the locking mechanism, taken
along line B-B in FIG. 11;
[0043] FIG. 13 is a left side view of the ceiling fan of FIG. 1
mounted to a ceiling, and with an annular nozzle of the ceiling fan
in a lowered position;
[0044] FIG. 14 is a top view of an annular casing of a second
example of a ceiling fan;
[0045] FIG. 15 is a bottom view of the annular casing of FIG.
14;
[0046] FIG. 16 is a front view of the annular casing of FIG.
14;
[0047] FIG. 17 is a top sectional view of the annular casing, taken
along line K-K in FIG. 16; and
[0048] FIG. 18(a) is a sectional view of the annular casing, taken
along line F-F in FIG. 17, FIG. 18(b) is a sectional view of the
annular casing, taken along line G-G in FIG. 17, FIG. 18(c) is a
sectional view of the annular casing, taken along line H-H in FIG.
17, FIG. 18(d) is a sectional view of the annular casing, taken
along line J-J in FIG. 17, and FIG. 18(e) is a sectional view of
the annular casing, taken along line L-L in FIG. 17.
DETAILED DESCRIPTION OF THE INVENTION
[0049] FIGS. 1 to 5 illustrate a first example of a fan assembly
for generating an air flow within a room. In this example, the fan
assembly is in the form of a ceiling fan 10 which is connectable to
a ceiling C of a room. The ceiling fan 10 comprises an air inlet
section 12, an air outlet section 14, and a support assembly 16 for
supporting the air inlet section 12 and the air outlet section 14
on the ceiling C of the room. The air outlet section 14 is in the
form of an annular nozzle connected to one end of the air inlet
section 12.
[0050] The air inlet section 12 comprises a generally cylindrical
outer casing 18 which houses a system for generating an air flow
which is emitted from the air outlet section 14. As indicated in
FIGS. 1, 2 and 5, the outer casing 18 may be formed with a
plurality of axially extending reinforcing ribs 20 which are spaced
about the longitudinal axis L of the outer casing 18, but these
ribs 20 may be omitted depending on the strength of the material
from which the outer casing 18 is formed.
[0051] With reference now to FIGS. 6 and 7, the air inlet section
12 houses an impeller 22 for drawing an air flow into the ceiling
fan 10. The impeller 22 is in the form of an axial flow impeller
which is rotatable about an impeller axis which is substantially
co-linear with the longitudinal axis L of the outer casing 18. The
impeller 22 is connected to a rotary shaft 24 extending outwardly
from a motor 26. In this example, the motor 26 is a DC brushless
motor having a speed which is variable by a control circuit (not
shown) located within the support assembly 16. The motor 26 is
housed within a motor casing comprising a front motor casing
section 28 and a rear motor casing section 30. During assembly, the
motor 26 is inserted first into the front motor casing section 28,
and the rear motor casing section 30 is inserted subsequently into
the front casing section 28 to both retain and support the motor 26
within the motor casing.
[0052] The air inlet section 12 also houses a diffuser located
downstream from the impeller 22. The diffuser comprises a plurality
of diffuser vanes 32 which are located between an inner cylindrical
wall 34 and an outer cylindrical wall of the diffuser. The diffuser
is preferably molded as a single body, but alternatively the
diffuser may be formed from a plurality of parts or sections which
are connected together. The inner cylindrical wall 34 extends about
and supports the motor casing. The outer cylindrical wall provides
a shroud 36 which extends about the impeller 22 and the motor
casing. In this example, the shroud 36 is substantially
cylindrical. The shroud 36 comprises an air inlet 38 at one end
thereof through which the air flow enters the air inlet section 12
of the ceiling fan 10, and an air outlet 40 at the other end
thereof through which the air flow is exhausted from the air inlet
section 12 of the ceiling fan 10. The impeller 22 and the shroud 36
are shaped so when the impeller 22 and motor casing are supported
by the diffuser, the blade tips of the impeller 22 are in close
proximity to, but do not contact, the inner surface of the shroud
36 and the impeller 22 is substantially co-axial with the shroud
36. A cylindrical guide member 42 is connected to the rear of the
inner cylindrical wall 34 of the diffuser for guiding the air flow
generated by the rotation of the impeller 22 towards the air outlet
40 of the shroud 36.
[0053] The air inlet section 12 comprises a mounting arrangement
for mounting the diffuser within the outer casing 18 so that the
impeller axis is substantially co-linear with the longitudinal axis
L of the outer casing 18. The mounting arrangement is located
within an annular channel 44 extending between the outer casing 18
and the shroud 36. The mounting arrangement comprises a first mount
46 and a second mount 48 which is axially spaced along the
longitudinal axis L from the first mount 46. The first mount 46
comprises a pair of interconnected arcuate members 46a, 46b which
are mutually axially spaced along the longitudinal axis L. The
second mount 48 similarly comprises a pair of interconnected
arcuate members 48a, 48b which are mutually axially spaced along
the longitudinal axis L. An arcuate member 46a, 48a of each mount
46, 48 comprises a plurality of spring connectors 50, each of which
is connected to one end of a respective tension spring (not shown).
In this example, the mounting arrangement comprises four tension
springs, with each of these arcuate members 46a, 48a comprising two
diametrically opposed connectors 50. The other end of each tension
spring is connected to a respective spring connector 52 formed in
the shroud 36. The mounts 46, 48 are urged apart by an arcuate
spacer ring 54 inserted into the annular channel 44 between the
mounts 46, 48 so that the tension springs are held in a state of
tension between the connectors 50, 52. This serves to maintain a
regular spacing between the shroud 36 and the mounts 46, 48 while
allowing a degree of radial movement of the shroud 36 relative to
the mounts 46, 48 to reduce the transmission of vibrations from the
motor casing to the outer casing 18. A flexible seal 56 is provided
at one end of the annular channel 44 to prevent part of the air
flow from returning to the air inlet 40 of the shroud 36 along the
annular channel 44.
[0054] An annular mounting bracket 58 is connected to the end of
the outer casing 18 which extends about the air outlet 42 of the
shroud 36, for example by means of bolts 60. An annular flange 62
of the air outlet section 14 of the ceiling fan 10 is connected to
the mounting bracket 58, for example, by means of bolts 64.
Alternatively, the mounting bracket 58 may be integral with the air
outlet section 14.
[0055] As mentioned above, the air outlet section 14 is in the form
of an annular nozzle. Returning to FIGS. 1 to 5, the nozzle
comprises an outer section 70 and an inner section 72 connected to
the outer section 70 at the upper end (as illustrated) of the
nozzle. The outer section 70 comprises a plurality of arcuate
sections which are connected together to define an annular outer
side wall 74 of the nozzle. The inner section 72 similarly
comprises a plurality of arcuate sections which are each connected
to a respective section of the outer section 70 to define in part
an annular inner side wall 76 of the nozzle. The inner wall 76
extends about a central bore axis X to define a bore 78 of the
nozzle. The bore axis X is substantially orthogonal to the
longitudinal axis L of the outer casing 18. The bore 78 has a
generally circular cross-section which varies in diameter along the
bore axis X. The nozzle also comprises an annular upper wall 80
which extends between one end of the outer wall 74 and one end of
the inner wall 76, and an annular lower wall 82 which extends
between the other end of the outer wall 74 and the other end of the
inner wall 76. The inner section 70 is connected to the outer
section 72 substantially midway along the upper wall 80, whereas
the outer section 72 of the nozzle forms the majority of the lower
wall 82.
[0056] With particular reference to FIG. 8, the nozzle also
comprises an annular outlet section 84. The outlet section 84
comprises an inner, generally frusto-conical inner wall 86 which is
connected to the lower end of the inner section 72 so as to define
a section of the annular inner side wall 76 of the nozzle. The
inner wall 86 tapers away from the bore axis X. In this example, an
angle subtended between the inner wall 86 and the bore axis X is
around 15.degree.. The outlet section 84 also comprises an annular
outer wall 88 which is connected to the lower end of the outer
section 70 of the nozzle, and which defines part of the annular
lower wall 82 of the nozzle. The inner wall 86 and the outer wall
88 of the outlet section 84 are connected together by a plurality
of webs (not shown) which serve to control the spacing between the
inner wall 86 and the outer wall 88 about the bore axis X. The
outlet section 84 may be formed as a single body, but it may be
formed as a plurality of components which are connected together.
Alternatively, the inner wall 86 may be integral with the inner
section 70 and the outer wall 88 may be integral with the outer
section 72. In this case, one of the inner wall 86 and the outer
wall 88 may be formed with a plurality of spacers for engaging the
other one of the inner wall 86 and the outer wall 88 to control the
spacing between the inner wall 86 and the outer wall 88 about the
bore axis X.
[0057] The inner wall 76 may be considered to have a
cross-sectional profile in a plane containing the bore axis X which
is in the shape of part of a surface of an airfoil. This airfoil
has a leading edge at the upper wall 80 of the nozzle, a trailing
edge at the lower wall 82 of the nozzle, and a chord line CL
extending between the leading edge and the trailing edge. In this
example, the chord line CL is generally parallel to the bore axis
X.
[0058] An air outlet 90 of the nozzle is located between the inner
wall 86 and the outer wall 88 of the outlet section 84. The air
outlet 90 may be considered to be located in the lower wall 82 of
the nozzle, adjacent to the inner wall 76 of the nozzle and thus
between the chord line CL and the bore axis X, as illustrated in
FIG. 6. The air outlet 90 is preferably in the form of an annular
slot. The slot is preferably generally circular in shape, and
located in a plane which is perpendicular to the bore axis X. The
slot preferably has a relatively constant width in the range from
0.5 to 5 mm.
[0059] The annular flange 62 for connecting the nozzle to the air
inlet section 12 is integral with one of the sections of the outer
section 70 of the nozzle. The flange 62 may be considered to extend
about an air inlet 92 of the nozzle for receiving the air flow from
the air inlet section 12. This section of the outer section 70 of
the nozzle is shaped to convey the air flow into an annular
interior passage 94 of the nozzle. The outer wall 74, inner wall
76, upper wall 80 and lower wall 82 of the nozzle together define
the interior passage 94, which extends about the bore axis X. The
interior passage 94 has a generally rectangular cross-section in a
plane which passes through the bore axis X.
[0060] As shown in FIG. 8, the interior passage 94 comprises an air
channel 96 for directing the air flow through the air outlet 90.
The width of the air channel 96 is substantially the same as the
width of the air outlet 90. In this example the air channel 96
extends towards the air outlet 90 in a direction D extending away
from the bore axis X so that the air channel 96 is inclined
relative to the chord line CL of the airfoil, and to the bore axis
X of the nozzle 102.
[0061] The angle of inclination of the bore axis X, or the chord
line CL, to the direction D may take any value. The angle is
preferably in the range from 0 to 45.degree.. In this example the
angle of inclination is substantially constant about the bore axis
X, and is around 15.degree.. The inclination of the air channel 96
to the bore axis X is thus substantially the same as the
inclination of the inner wall 86 to the bore axis X.
[0062] The air flow is thus emitted from the nozzle in a direction
D which is inclined to the bore axis X of the nozzle. The air flow
is also emitted away from the inner wall 76 of the nozzle 104. By
controlling the shape of the air channel 96 so that the air channel
96 extends away from the bore axis X, the flow rate of the combined
air flow generated by the ceiling fan 10 can be increased in
comparison to that of the combined air flow generated when the air
flow is emitted in a direction D which is substantially parallel to
the bore axis X, or which is inclined towards the bore axis X.
Without wishing to be bound by any theory we consider this to be
due to the emission of an air flow having an outer profile with a
relatively large surface area. In this example, an air flow is
emitted from the nozzle generally in the shape of an outwardly
tapering cone. This increased surface area promotes mixing of the
air flow with air surrounding the nozzle, increasing the degree of
entrainment of ambient air by the emitted air flow and thereby
increasing the flow rate of the combined air flow.
[0063] Returning again to FIGS. 1 to 5, the support assembly 16
comprises a ceiling mount 100 for mounting the ceiling fan 10 on a
ceiling C, an arm 102 having a first end connected to the ceiling
mount 100 and a second end connected to a body 104 of the support
assembly 100. The body 104 is, in turn, connected to the air inlet
section 12 of the ceiling fan 10.
[0064] The ceiling mount 100 comprises a mounting plate 106 which
is connectable to a ceiling C of a room using screws insertable
through apertures 108 in the mounting plate 106. With reference to
FIGS. 9 and 10, the ceiling mount 100 further comprises a coupling
assembly for coupling a first end 110 of the arm 102 to the
mounting plate 106. The coupling assembly comprises a coupling disc
112 which has an annular rim 114 which is received within an
annular groove 116 of the mounting plate 106 so that the coupling
disc 112 is rotatable relative to the mounting plate 106 about a
rotational axis R. The arm 102 is inclined to the rotational axis R
by an angle .theta. which is preferably in the range from 45 to
75.degree., and in this example is around 60.degree.. Consequently,
as the arm 102 is rotated about the rotational axis R, the air
inlet section 102 and the nozzle orbit about the rotational axis
R.
[0065] The first end 110 of the arm 102 is connected to the
coupling disc 112 by a number of coupling members 118, 120, 122 of
the coupling assembly. The coupling assembly is enclosed by an
annular cap 124 which is secured to the mounting plate 106, and
which includes an aperture through which the first end 110 of the
arm 102 protrudes. The cap 124 also surrounds an electrical
junction box 126 for connection to electrical wires for supplying
power to the ceiling fan 10. An electrical cable (not shown)
extends from the junction box 126 through apertures 128, 130 formed
in the coupling assembly, and aperture 132 formed in the first end
100 of the arm, and into the air 102. As illustrated in FIGS. 9 to
11, the arm 102 is tubular, and comprises a bore 134 extending
along the length of the arm 102 and within which the electrical
cable extends from the ceiling mount 100 to the body 104.
[0066] The second end 136 of the arm 102 is connected to the body
104 of the support assembly 16. The body 104 of the support
assembly 16 comprises an annular inner body section 138 and an
annular outer body section 140 extending about the inner body
section 138. The inner body section 138 comprises an annular flange
142 which engages a flange 144 located on the outer casing 18 of
the air inlet section 12. An annular connector 146, for example a
C-clip, is connected to the flange 142 of the inner body section
138 so as to extend about and support the flange 144 of the outer
casing 18 so that the outer casing 18 is rotatable relative to the
inner body section 138 about the longitudinal axis L. An annular
inlet seal 148 forms an air-tight seal between the shroud 36 and
the flange 142 of the inner body section 138.
[0067] The air inlet section 12 and the nozzle, which is connected
to the outer casing 18 by the mounting bracket 58, are thus
rotatable relative to the support assembly 16 about the
longitudinal axis L. This allows a user to adjust the orientation
of the nozzle relative to the support assembly 16, and thus
relative to a ceiling C to which the support assembly 16 is
connected. To adjust the orientation of the nozzle relative to the
ceiling C, the user pulls the nozzle so that the air inlet section
12 and the nozzle both rotate about the longitudinal axis L. For
example, during the summer the user may wish to orient the nozzle
so that the air flow is emitted away from the ceiling C and into a
room so that the air flow generated by the fan provides a
relatively cool breeze for cooling a user located beneath the
ceiling fan 10. During the winter however, the user may wish to
invert the nozzle through 180.degree. so that the air flow is
emitted towards the ceiling C to displace and circulate warm air
which has risen to the upper portions of the walls of the room,
without creating a breeze directly beneath the ceiling fan.
[0068] In this example, both the air inlet section 12 and the
nozzle are rotatable about the longitudinal axis L. Alternatively,
the ceiling fan 10 may be arranged so that the nozzle is rotatable
relative to the outer casing 18, and thus relative to both the air
inlet section 12 and the support assembly 16. For example, the
outer casing 18 may be secured to the inner body section 138 by
means of bolts or screws, and the nozzle may be secured to the
outer casing 18 in such a manner that it is rotatable relative to
the outer casing 18 about the longitudinal axis L. In this case,
the manner of connection between the nozzle and the outer casing 18
may be similar to that effected between the air inlet section 12
and the support assembly 16 in this example.
[0069] Returning to FIG. 11, the inner body section 138 defines an
air passage 150 for conveying the air flow to the air inlet 38 of
the air inlet section 12. The shroud 36 defines an air passage 152
which extends through the air inlet section 12, and the air passage
152 of the support assembly 16 is substantially co-axial with the
air passage 150 of the air inlet section 12. The air passage 150
has an air inlet 154 which is orthogonal to the longitudinal axis
L.
[0070] The inner body section 138 and the outer body section 140
together define a housing 156 of the body 104 of the support
assembly 16. The housing 156 may retain a control circuit (not
shown) for supplying power to the motor 26. The electrical cable
extends through an aperture (not shown) formed in the second end
136 of the arm 102 and is connected to the control circuit. A
second electrical cable (not shown) extends from the control
circuit to the motor 26. The second electrical cable passes through
an aperture formed in the flange 142 of the inner body section 138
of the body 104 and enters the annular channel 44 extending between
the outer casing 18 and the shroud 36. The second electrical cable
subsequently extends through the diffuser to the motor 26. For
example, the second electrical cable may pass through a diffuser
vane 32 of the shroud and into the motor casing. A grommet may be
located about the second electrical cable to form an air-tight seal
with the peripheral surface of an aperture formed in the shroud 36
to inhibit the leakage of air through this aperture. The body 104
may also comprise a user interface which is connected to the
control circuit for allowing the user to control the operation of
the ceiling fan 10. For example, the user interface may comprise
one or more buttons or dials for allowing the user to activate and
de-activate the motor 26, and to control the speed of the motor 26.
Alternatively, or additionally, the user interface may comprise a
sensor for receiving control signals from a remote control for
controlling the operation of the ceiling fan 10.
[0071] Depending on the radius of the outer wall 74 of the nozzle,
the length of the arm 102 and the shape of the ceiling to which the
ceiling fan 10 is connected, the distance between the longitudinal
axis L of the outer casing 18, about which the nozzle rotates, and
the ceiling may be shorter than the radius of the outer wall 74 of
the nozzle, which would inhibit rotation of the nozzle through
90.degree. about the longitudinal axis L. In order to allow the
nozzle to be inverted, the body 104 of the support assembly 16 is
pivotable relative to the arm 102 about a first pivot axis P1 to
move the annular nozzle between a raised position, as illustrated
in FIG. 2, and a lowered position, as illustrated in FIG. 13. The
first pivot axis P1 is illustrated in FIG. 11. The first pivot axis
P1 is defined by the longitudinal axis of a pin 158 which extends
through the second end 136 of the arm 102, and which has ends
retained by the inner body section 138 of the body 104. The first
pivot axis P1 is substantially orthogonal to the rotational axis R
about which the arm 102 rotates relative to the ceiling mount 100.
The first pivot axis P1 is also substantially orthogonal to the
longitudinal axis L of the outer casing 18.
[0072] In the raised position illustrated in FIG. 2, the
longitudinal axis L of the outer casing 18, and thus the impeller
axis, is substantially parallel to the mounting plate 106. This can
allow the nozzle to be oriented so that the bore axis X is
substantially perpendicular to the longitudinal axis L and to a
horizontal ceiling C to which the ceiling fan 10 is attached. In
the lowered position, the longitudinal axis L of the outer casing
18, and thus the impeller axis, is inclined to the mounting plate
106, preferably by an angle of less than 90.degree. and more
preferably by an angle of less than 45.degree.. The body 104 may be
pivotable relative to the arm 102 about an angle in the range from
5 to 45.degree. to move the nozzle from the raised position to the
lowered position. Depending on the radius of the outer wall 74 of
the nozzle, a pivoting movement about an angle in the range from 10
to 20.degree. may be sufficient to lower the nozzle sufficiently to
allow the nozzle to be inverted without contacting the ceiling. In
this example, the body 104 is pivotable relative to the arm 102
about an angle of around 12 to 15.degree. to move the nozzle from
the raised position to the lowered position.
[0073] The housing 156 of the body 104 also houses a releasable
locking mechanism 160 for locking the position of the body 104
relative to the arm 102. The locking mechanism 160 serves to retain
the body 104 in a position whereby the nozzle is in its raised
position. With reference to FIGS. 11 and 12, in this example the
locking mechanism 160 comprises a locking wedge 162 for engaging
the second end 136 of the arm 102 and an upper portion 164 of the
body 104 to inhibit relative movement between the arm 102 and the
body 104. The locking wedge 162 is connected to the inner body
section 138 for pivoting movement relative thereto about a second
pivot axis P2. The second pivot axis P2 is substantially parallel
to the first pivot axis P1. The locking wedge 162 is retained in a
locking position illustrated in FIG. 11 by a locking arm 166 which
extends about the inner body section 138 of the body 104. A locking
arm roller 168 is rotatably connected to the upper end of the
locking arm 166 to engage the locking wedge 162, and to minimize
frictional forces between the locking wedge 162 and the locking arm
166. The locking arm 166 is connected to the inner body section 138
for pivoting movement relative thereto about a third pivot axis P3.
The third pivot axis P3 is substantially parallel to the first
pivot axis P1 and the second pivot axis P2. The locking arm 166 is
biased towards the position illustrated in FIG. 11 by a resilient
element 170, preferably a spring, located between the locking arm
166 and the flange 142 of the inner body section 138.
[0074] To release the locking mechanism 160, the user pushes the
locking arm 166 against the biasing force of the resilient element
170 so as to pivot the locking arm 166 about the third pivot axis
P3. The outer body section 140 comprises a window 172 through which
a user may insert a tool to engage the locking arm 166.
Alternatively, a user operable button may be attached to the lower
end of the locking arm 166 so as to protrude through the window 172
for depression by the user. The movement of the locking arm 166
about the third pivot axis P3 moves the locking arm roller 168 away
from the second end 136 of the arm 102, thereby allowing the
locking wedge 162 to pivot about the second pivot axis P2 away from
its locking position and out of engagement with the second end 136
of the arm 102. The movement of the locking wedge 162 away from its
locking position allows the body 104 to pivot relative to the arm
102 about the first pivot axis P1 and so move the nozzle from its
raised position to its lowered position.
[0075] Once the user has rotated the nozzle about the longitudinal
axis L by the desired amount, the user can return the nozzle to its
raised position by lifting the end of the nozzle so that the body
104 pivots about the first pivot axis P1. As the locking arm 166 is
biased towards the position illustrated in FIG. 11, the return of
the nozzle to its raised position causes the locking arm 166 to
return automatically to the position illustrated in FIG. 11, and so
return the locking wedge 162 to its locking position.
[0076] To operate the ceiling fan 10 the user depresses an
appropriate button of the user interface or the remote control. A
control circuit of the user interface communicates this action to
the main control circuit, in response to which the main control
circuit activates the motor 26 to rotate the impeller 22. The
rotation of the impeller 22 causes an air flow to be drawn into the
body 104 of the support assembly 16 through the air inlet 150. The
user may control the speed of the motor 26, and therefore the rate
at which air is drawn into the support assembly 16, using the user
interface or the remote control. The air flow passes sequentially
along the air passage 150 of the support assembly 16 and the air
passage 152 of the air inlet section, to enter the interior passage
94 of the nozzle.
[0077] Within the interior passage 94 of the nozzle, the air flow
is divided into two air streams which pass in opposite directions
around the bore 78 of the nozzle 16. As the air streams pass
through the interior passage 94, air is emitted through the air
outlet 90. As viewed in a plane passing through and containing the
bore axis X, the air flow is emitted through the air outlet 90 in
the direction D. The emission of the air flow from the air outlet
90 causes a secondary air flow to be generated by the entrainment
of air from the external environment, specifically from the region
around the nozzle. This secondary air flow combines with the
emitted air flow to produce a combined, or total, air flow, or air
current, projected forward from the nozzle.
[0078] FIGS. 14 to 16 illustrate a second example of a fan assembly
for generating an air flow within a room. In this second example,
the fan assembly 200 forms part of a ceiling fan which is
connectable to a ceiling of a room. A support assembly (not shown)
is provided for supporting the fan assembly 200 on the ceiling of
the room. The support assembly 16 of the ceiling fan 10 may be
connected to the fan assembly 200 to support the fan assembly 200
on the ceiling, and so the support assembly will not be described
further in connection with this second example.
[0079] In this second example, the fan assembly 200 is in the form
of an annular casing having an interior passage 202 having an air
inlet 204 and an air outlet 206. The casing has an annular air
outlet section 208 which defines the air outlet 206 and an outlet
section 210 of the interior passage 202, and an arcuate air inlet
section 212 which extends partially about the air outlet section
208 of the casing, and defines the air inlet 204 and an inlet
section 214 of the interior passage 202.
[0080] The air outlet section 208 of the casing comprises an inner
casing section and an outer casing section connected to the inner
section at the upper end (as illustrated) of the casing. With
reference to FIG. 14, the inner casing section comprises a
plurality of arcuate sections 216a, 216b, 216c, 216d which are
connected together to define an upper part 218a of a first annular
side wall 218 of the casing. The first side wall 218 extends about
a central bore axis X to define a bore 222 of the casing. The bore
222 has a generally circular cross-section. The outer casing
section also comprises a plurality of arcuate sections 224a, 224b,
224c, 224d, 224e which are connected to the inner casing section.
With reference also to FIGS. 17 and 18(a) to 18(e), sections 224a,
224b, 224c, 224d of the outer casing section and section 216a of
the inner casing section together define a second side wall 226 of
the casing. The second side wall 226 extends about the first side
wall 218. Sections 224a, 224b, 224c, 224d of the outer casing
section and section 216a of the inner casing section also together
define an upper wall 228 which extends between the side walls 218,
226 of the casing.
[0081] The air outlet section 208 of the casing also comprises an
outlet casing section which is connected to the inner casing
section and the outer casing section. With reference to FIG. 15,
the outlet casing section also comprises a plurality of arcuate
sections 230a, 230b, 230c, 230d, 230e, 230f. Each arcuate section
of the outlet casing section extends from a lower end of the upper
part 218a of the first side wall 218 to an arcuate section of the
outer casing section to define a lower part 218b of the first side
wall 218 and a lower wall 232 located opposite to the upper wall
228. The external surface of the lower part 218b of the first side
wall 218 is generally frusto-conical in shape so as to taper away
from the bore axis X. In this example, an angle subtended between
the bore axis X and the external surface of the lower part 218b of
the first side wall 218 is around 15.degree..
[0082] The outlet section 210 of the interior passage 202 is thus
defined by the side walls 218, 226, upper wall 228 and lower wall
232 of the casing. The outlet section 210 of the interior passage
202 has a generally rectangular cross-section.
[0083] The second side wall 226 extends substantially 360.degree.
about the first side wall 218. As illustrated most clearly in FIG.
17, the radial distance between the side walls 218, 226 varies
about the bore axis X so that the outlet section 210 of the
interior passage 202 is in the form of a scroll section having a
cross-sectional that varies continuously about the bore axis X. The
outlet section 210 has a relatively wide scroll inlet section 234
and a relatively narrow scroll outlet section 236, with the
cross-sectional area of the outlet section 210 decreasing
continuously between these sections 234, 236. With reference also
to FIG. 18(e), the scroll inlet section 234 has an inlet port 238
for receiving the air flow from the air inlet section 212 of the
casing, and the scroll outlet section 236 has an outlet port 240
for returning a first portion of the air flow to the scroll inlet
section 234. The outlet section 210 of the interior passage 202 is
thus continuous about the bore axis X.
[0084] The inlet port 238 is located between the ends 242, 244 of
the second side wall 226. The outlet port 240 is located between
the first side wall 218 and one end 242 of the second side wall
226. The outlet port 240 is located adjacent to the inlet port 238.
As illustrated in FIG. 17, the inlet port 238 and the outlet port
240 are preferably substantially co-planar.
[0085] The outlet casing section defines the air outlet 206 of the
casing, through which a second portion of the air flow is emitted
from the casing. In this example, the air outlet 206 is preferably
in the form of an annular slot. The slot is preferably generally
circular in shape, and located in a plane which is perpendicular to
the bore axis X. The slot preferably has a relatively constant
width in the range from 0.5 to 5 mm. The air outlet 206 is located
between the lower part 218b of the first side wall 218 and the
lower wall 232. The internal surface of the lower part 218b of the
first side wall 218 is shaped to guide the second portion of the
air flow through the air outlet 206 in a direction which is
inclined to, and extends away from, the bore axis X. Similar to the
first example, the second portion of the air flow is emitted
through the air outlet 206 in a direction which is inclined at an
angle of around 15.degree. to the bore axis X.
[0086] The lower part 218b of the first side wall 218 and the lower
wall 232 are connected together by a plurality of webs 252 which
serve to control the width of the slot. As illustrated in FIGS. 15
and 17, these webs 252 are angularly spaced about the bore axis X.
As with the first example, the upper part 218a and the lower part
218b of the first side wall 218 may be integral, and the lower wall
232 may be integral with the second side wall 226. In this case,
one of the side walls may be formed with a plurality of spacers for
engaging the other side wall to control the spacing between the
side walls, and thus the width of the air outlet 206, about the
bore axis X.
[0087] As mentioned above, the casing has an arcuate air inlet
section 212 which extends partially about the air outlet section
208 of the casing, and defines the air inlet 204 of the fan
assembly 200 and an inlet section 214 of the interior passage 202.
The inlet section 214 of the interior passage 202 conveys the air
flow from the air inlet 204 to the inlet port 238 of the scroll
inlet section 234. Similar to the first example, the inlet section
214 houses an impeller 22 for drawing the air flow into the fan
assembly 200, and a motor 26 for driving the impeller 22. The inlet
section 214 also houses a diffuser located downstream from the
impeller 22, and comprising a plurality of diffuser vanes 32. The
impeller 22, motor 26 and diffuser are located within a generally
cylindrical impeller housing section 254 of the air inlet section
212. The impeller housing section 254 is defined by section 224e of
the outer casing section.
[0088] The impeller 22 has a longitudinal axis L, with the impeller
22 being arranged within the impeller housing section 254 so that
the longitudinal axis L is substantially orthogonal to, but does
not intersect, the bore axis X. The arrangement of the impeller 22,
motor 26 and diffuser within the impeller housing section 254 is
substantially the same as the arrangement of those components
within the cylindrical outer casing 18 of the air inlet section 12
of the ceiling fan 10, and so the arrangement of these components
within the impeller housing section 254 will not be described again
here. A control circuit for receiving control signals from a remote
control, and for controlling the motor 26 in response to the
received control signals, may be located within the impeller
housing section 254. Alternatively, or additionally, a user
interface may be located on the impeller housing section 254. This
user interface may comprise one or more buttons or dials for
allowing the user to activate and de-activate the motor 26, and to
control the speed of the motor 26.
[0089] A mounting arrangement for mounting those components within
the impeller housing section 254 may be substantially the same as
the arrangement of those components within the cylindrical outer
casing 18 of the air inlet section 12 of the ceiling fan 10, and so
that mounting arrangement also will not be described again here.
The impeller housing section 254 may also comprise a first
silencing arrangement 256 located upstream from the impeller 22,
and a second silencing arrangement 258 located downstream from the
diffuser vanes 32. Each silencing arrangement 256, 258 may comprise
one or more of acoustic foam and a plurality of Helmholtz
resonators. As the impeller housing section 254 has a generally
cylindrical cross-section, the inlet section 214 of the interior
passage 202 comprise an intermediate section 260 of varying
cross-section which connects the impeller housing section 254 to
the outlet section 210 of the interior passage 202. The
intermediate section 260 is also defined by section 224e of the
outer casing section.
[0090] The inlet section 214 of the interior passage 202 further
comprises a conduit 262 which conveys the air flow from the air
inlet 204 to the impeller housing section 254. The conduit 262
extends about the air outlet section 208 of the casing, and is
arcuate in shape. The air inlet 204 is located at one end of the
conduit 262. In this example, the conduit 262 comprises a first
conduit section 262a which is connected to section 224d of the
outer casing section, and a second conduit section 262b which is
connected between the first conduit section 262a and the impeller
housing section 254. The conduit 262 may comprise any number of
such conduit sections so as to extend about the air outlet section
208 of the casing by a greater or lesser extent. In this example,
the conduit 262 has a generally rectangular cross-section, and so
the inlet section 214 of the interior passage 202 comprises a
second intermediate section 264 of varying cross-section which
connects the conduit 262 to the impeller housing section 254.
[0091] The air inlet section 212 of the casing may further comprise
one or more silencing arrangements. In this example, the air inlet
section 212 comprises two arcuate sections 266a, 266b of silencing
foam located on opposite sides of the first conduit section 262a,
and an arcuate section 266c of silencing foam located on one side
of the second conduit section 262b.
[0092] The air inlet 204 is a tangential air inlet, in that the air
inlet admits the air flow into the fan assembly 200 in a direction
which is substantially tangential to the bore 222 of the casing.
This allows the air flow to enter the interior passage 202 of the
casing without any sharp changes in the direction of the air flow,
and so can reduce noise generated by turbulence upstream from the
impeller. The support assembly 16 of the ceiling fan 10 may be
connected to the air inlet 204.
[0093] To operate the fan assembly 200 the user depresses an
appropriate button of the user interface or the remote control. A
control circuit of the user interface communicates this action to
the main control circuit, in response to which the main control
circuit activates the motor 26 to rotate the impeller 22. The
rotation of the impeller 22 causes an air flow to be drawn into the
air inlet section 214 of the interior passage 202 through the air
inlet 204. The user may control the speed of the motor 26, and
therefore the rate at which air is drawn into the interior passage
202, using the user interface or the remote control. The air flow
passes sequentially through the conduit 262, the second
intermediate section 264, the impeller housing section 254 and the
intermediate section 260 to enter the outlet section 210 of the
interior passage 202 through the inlet port 238. As the air flow
passes through the outlet section 210 of the interior passage 202,
a portion of the air flow is emitted through the air outlet 206. As
viewed in a plane passing through and containing the bore axis X,
this portion of the air flow is emitted through the air outlet 206
in a direction D extending away from the bore axis X. The emission
of this portion of the air flow from the air outlet 206 causes a
secondary air flow to be generated by the entrainment of air from
the external environment, specifically from the region around the
fan assembly 200. This secondary air flow combines with the emitted
air flow to produce a combined, or total, air flow, or air current,
projected forward from the fan assembly 200.
[0094] As discussed above, another portion of the air flow passes
through the outlet port 240 to re-enter the scroll inlet section
234. The return of this portion of the air flow to the scroll inlet
section 234 allows air to be emitted from the air outlet 206 at a
substantially constant velocity about the bore axis X. As mentioned
above, the inlet port 238 and the outlet port 240 are substantially
co-planar so that the direction in which the portion of the air
flow re-enters the scroll inlet section 234 is substantially the
same as the direction in which the air flow enters the scroll inlet
section 234. This can minimize the generation of turbulence within
the scroll inlet section 234.
* * * * *