Source: http://www.patentsencyclopedia.com/app/20130017104
Timestamp: 2016-09-27 09:30:42
Document Index: 245687662

Matched Legal Cases: ['art\n218', 'art 218', 'art 218', 'art\n218', 'art 218', 'art 218', 'art 218', 'art 218', 'art 218', 'art 218']

Neil Andrew Stewart (Malmesbury, GB)
Mark James Adkin (Malmesbury, GB)
David Andrew Tibbetts (Malmesbury, GB)
Patent application number: 20130017104
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.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
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:
[0001] This application claims the priority of United Kingdom Application
No. 1112215.7, filed Jul. 15, 2011, the entire contents of which are
[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.
[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.
[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
[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°. 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
[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
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
[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
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
[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° to the mounting plate. The impeller axis is more preferably at
an angle of less than 45° 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
[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° 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
[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
[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
[0044] FIG. 14 is a top view of an annular casing of a second example of a
[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.
[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°. 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°. In this example the angle of inclination is
substantially constant about the bore axis X, and is around 15°.
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
[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 θ which is preferably in the range
from 45 to 75°, and in this example is around 60°.
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° 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
[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° 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° and
more preferably by an angle of less than 45°. The body 104 may be
pivotable relative to the arm 102 about an angle in the range from 5 to
45° 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° 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° to move the nozzle from the raised position to the lowered
[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
[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
[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°.
[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
[0083] The second side wall 226 extends substantially 360° 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° 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
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
[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
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.
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1Masaki Ota
2Ken Suitou
3Alex Horng
4Lars Hoffmann Berthelsen
5Robert W. Stiles, Jr.