Technical Field
[0001] The present invention relates to an air conditioner, and more particularly, to an
improvement in a fan guard which is attached to an outlet port through which air having
been heat-exchanged is guided and discharged to the outside after the air is sent
to a heat exchanger and subjected to heat exchange and which is composed of concentric
circular slats and radial slats.
Background Art
[0002] Separate type air conditioners, which are composed of an indoor unit disposed in
a room to be air conditioned and an outdoor unit disposed in the open air and communicating
with the indoor unit through refrigerant piping or the like, have been in heavy use.
[0003] In particular, the outdoor unit includes a heat exchanger and an outdoor blower disposed
in a cabinet serving as a unit main body in confrontation with each other. Further,
inlet ports are disposed on the back surface and side surfaces of the cabinet, and
an outlet port is disposed on the front surface of the cabinet.
[0004] In particular, since the outlet port is disposed on the front surface of the cabinet,
it is contemplated that a person might insert a finger into the cabinet by mistake
or that an object might get into the cabinet. To cope with this problem, a fan guard
for preventing invasion of a finger and an object is attached to the outlet port in
such a degree as not to obstruct ventilation of heat-exchanged air.
[0005] Conventionally, a front surface of an outdoor unit is arranged as shown in, for example,
FIG. 13. An outlet port 102 is opened through the front surface of a cabinet 101,
and a fan guard 103 is fitted to the outlet port 102. The fan guard 103 is composed
of a plurality of circular slats 104 disposed concentrically at a predetermined pitch
and a plurality of radial slats 105 that intersec the circular slats 104 as well as
extend radially from the center of the circular slats 104 to the outermost periphery
thereof.
[0006] The circular slats 104 and the radial slats 105 are molded of, for example, a synthetic
resin material. Further, from geometric characteristics, the intervals between the
radial slats 105 are made smaller as they come nearer to the center of the circular
slats 104. It is needless to say that the intervals between the radial slats 105 are
designed such that necessary strength is maintained at the outermost periphery of
the fan guard 103.
[0007] In the conventional fan guard 103, the intervals between the radial slats 105 are
set based on design strength that is necessary at the outermost periphery. Thus, the
intervals are set more densely than necessary intervals calculated from the strength
of the fan guard as they come nearer to the center of the circular slats 104. This
arrangement results in radial slats 105 having a large resistance against air flow.
[0008] Further, since the strength of the synthetic resin material, which constitutes the
circular slats 104 and the radial slats 105, is insufficient, these slats are formed
to have a large wall thickness to increase the strength thereof. As a result, a disadvantage
arises in that actual ventilation areas are reduced and ventilation resistance is
increased.
[0009] JP 05071766A discloses an air conditioner with a heat exchanger and a blower disposed in a cabinet.
An outlet port of the cabinet is closed by a fan guard to prevent invasion of objects
into the interior. The fan guard is constituted by a plurality of concentrically disposed
circular slats and a plurality of radial slats extending continuously from a centre
of the fan guard to the corners of a square frame and to the centre portions of the
sides of the frame, thereby intersecting the circular slats.
[0010] JP-A-8247097 discloses an air conditioner in which the fan guard is formed by a plurality of equidistantly
spaced parallel slats which are horizontally oriented and by vertical slats arranged
in the intervals between two adjacent horizontal slats so as to be equidistantly spaced
from the adjacent horizontal vertical slat and so as to be centred with respect to
the interval of the vertically adjacent slats such that the vertical slats of each
alternate row are aligned.
DISCLOSURE OF INVENTION
[0011] The present invention provides an air conditioner with the features of claim 1. Preferred
embodiments are defined in the dependent claims.
Brief Description of Drawings
[0012]
FIG. 1 is a schematic lateral plan view of an outdoor unit constituting an air conditioner
showing an embodiment of the present invention;
FIGS. 2A to 2C are views explaining a structural shape and air blasting characteristics
of a propeller fan constituting an outdoor blower showing the embodiment of the present
invention;
FIG. 3A is a front view of an outdoor unit having a fan guard of a first embodiment
of the invention;
FIG. 3B is a front view explaining a feature of circular slats and radial slats constituting
the fan guard;
FIG. 4 is a front view of an outdoor unit having a fan guard as a modification of
the first embodiment;
FIG. 5 is a view showing the characteristics of operation noise of an outdoor blower
to a quantity of supplied air when the outdoor blower is provided with the fan guard
of the first embodiment and with a fan guard of a conventional structure;
FIGS. 6A and 6B are front views of outdoor units each having a fan guard as a different
modification of the first embodiment;
FIG. 7A is a front view of an outdoor unit having a fan guard of a second example
not belonging to the invention;
FIG. 7B is a front view explaining a feature of circular slats and radial slats constituting
the fan guard;
FIG. 8 is a front view of an outdoor unit having a fan guard as a modification of
the second example;
FIG. 9 is a front view showing a part of a fan guard as another modification of the
second example;
FIGS. 10A to 10D are views explaining a structural shape and a sectional shape of
circular slats and radial slats which are applied to the first embodiment and second
example ;
FIG. 11A is a front view of an outdoor unit having a fan guard according to a technical
reference example;
FIG. 11B is a front view explaining a feature of circular slats and radial slats constituting
the fan guard;
FIG. 12 is a front view of an outdoor unit having a fan guard; and
FIG. 13 is a front view showing an outdoor unit having a conventional fan guard.
Best Mode for Carrying Out the Invention
[0013] Embodiments of the present invention will be explained below with reference to the
drawings. FIG. 1 is a lateral sectional view showing an outdoor unit 1 in a separate
type air conditioner having an indoor unit and an outdoor unit.
[0014] In FIG. 1, reference numeral 10 denotes a cabinet serving as a unit main body, and
the interior of the cabinet 10 is partitioned into a heat exchange chamber 12 and
a machine chamber 13 by a partition plate 11. An outdoor heat exchanger 14, which
is formed in an L-shape when viewed in a plan view, is disposed in the heat exchange
chamber 12, and further an outdoor blower 15 is disposed in confrontation with the
outdoor heat exchanger 14.
[0015] A compressor 16 is disposed in the machine chamber 13 and connected to the outdoor
heat exchanger 14, an indoor heat exchanger and the like disposed in an indoor unit
(not shown) through refrigerant piping so as to constitute a refrigerating cycle circuit.
[0016] The outdoor blower 15 is composed of a fan motor 15m and a propeller fan 15f to be
fitted to a rotary shaft of the fan motor 15m. Since the propeller fan 15f is attached
in confrontation with the front surface of the cabinet 10, the front surface of the
cabinet 10 acts as an outlet side, and the back surface thereof acts as an inlet side.
Since the outdoor heat exchanger 14 is interposed between the back surface of the
cabinet 10 and the propeller fan 15f, it is positioned on the inlet side of the propeller
fan 15f.
[0017] In contrast, inlet ports 17 are disposed on the back surface of the heat exchange
chamber 12 and on a side surface of the cabinet 10, respectively. That is, external
air is sucked into the cabinet 10 through the inlet ports 17 by driving the outdoor
blower 15.
[0018] Further, an outlet port 18 is disposed in the cabinet 10 on the font surface side
of the heat exchange chamber 12. External air sucked from the inlet ports 17 by driving
the outdoor blower 15 passes through the outdoor heat exchanger 14, is heat exchanged
therein, and blasted out from the outlet port 18.
[0019] A fan guard 20, which will be described later, is fitted to the outlet port 18 to
reliably prevent insertion of a finger and an object thereinto. It is needless to
say that the fan guard 20 is designed with such dimensions and shape that it does
not act as a ventilation resistance against heat-exchanged air to be vented through
the outlet port 18.
[0020] Note that, as shown in FIGS. 2A, 2B, and 2C, when the propeller fan 15f is driven
in rotation clockwise (in the direction of an arrow φ) in FIG. 2B, the intensity of
a blown-off stream of air from the propeller fan 15f is increased in the sequence
of directions Va, Vb, and Vc from a center shaft K to an outer periphery as shown
in FIG. 2C. Further, when a blowing-off angle α is set from a small angle (parallel
to an axial center) to a large angle (large angle with respect to the axial angle)
in the sequence of Wa, Wb, Wc as shown in FIG. 2A, the propeller fan 15f has such
characteristics that the intensity of the blown-off stream of air increases in the
above sequence.
[0021] Next, the fan guard 20 will be described in detail. FIG. 3A shows the front surface
of the cabinet 10, and the fan guard 20 of the first embodiment is fitted to the outlet
port 18. The fan guard 20 is composed of a plurality of slats 21 molded integrally
using a synthetic resin material.
[0022] The slats 21 are composed of a plurality of circular slats 24 disposed concentrically
at a predetermined pitch from a center to an outermost periphery and a plurality of
radial slats 25 intersecting the circular slats 24 and disposed radially from the
center of the circular slats 24 to the outermost periphery thereof. Note that the
radial slats 25 are composed of three kinds of radial slats 25a to 25c depending on
their lengths.
[0023] Basically, an interval between the radial slats 25, which are located adjacent to
each other in a peripheral direction, gradually increase from the center of the circular
slats 24 to the outermost periphery thereof (gradually decreases from the outermost
periphery of the circular slats 24 to the center thereof). However, the radial slats
25 are disposed here as described below.
[0024] That is, the radial slats 25, which are located on the same straight line from the
outermost periphery of the circular slats 24 to the center thereof, are disposed on
the concentric circles formed between the circular slats 24 at every other pitch.
The radial slats 25, which are located adjacent to each other in the peripheral direction,
are disposed on the concentric circles formed between the circular slats 24 at every
other pitch from the concentric circles between circular slats 24 displaced at one
pitch toward the center of the circular slats 24. From the above arrangement, the
radial slats 25 are disposed alternately with respect to the concentric circles of
the circular slats 24.
[0025] Then, as described later, when the interval between the radial slats 25 located adjacent
to each other on a predetermined concentric circle between the circular slats 24 reaches
a predetermined interval, an end of one of the radial slats 25 is lacking, and the
portion of the radial slat 25 located forward of the end is thinned out.
[0026] This will be specifically described based on FIG. 3B. When the radial slats 25b,
25b are disposed on both the side of the radial slats 25a in a radial direction and
the radial slats 25c, 25c are disposed on both the side of the radial slats 25b, 25b
adjacent thereto in the radial direction, the radial slat 25a and radial slats 25c
are disposed on the same concentric circle Ra between the circular slats 24 and no
radial slat 25b is disposed on the concentric circle.
[0027] The radial slats 25b are disposed on a concentric circle Rb displaced at one pitch
from the concentric circle Ra, on which the radial slat 25a and the radial slats 25c
are disposed, between the circular slats 24. Further, the radial slat 25a and the
radial slats 25c are disposed on the concentric circle Ra displaced at one pitch from
the concentric circle Rb. Thereafter, the radial slat 25a and radial slats 25c are
disposed on each concentric circle Ra between the circular slats 24, and the radial
slats 25b are disposed on each concentric circle Rb between the circular slats 24,
that is, the radial slat 25a and radial slats 25c and the radial slats 25b are disposed
at every other pitch. Accordingly, the radial slats 25a, 25c and the radial slats
25b are disposed alternately.
[0028] It is assumed here that the interval in the peripheral direction between adjacent
radial slats 25a, 25c disposed on an outermost peripheral concentric circle Ra is
shown by Q. Thus, the interval in the radial direction between adjacent radial slats
25b, 25b disposed on an outermost peripheral concentric circle Rb is slightly smaller
than the interval Q. The interval in the peripheral direction between the adjacent
radial slats 25a, 25c disposed on the concentric circle Ra located inward of the concentric
circle Rb is more smaller than the interval Q. Then, ends of the radial slats 25b,
25b are lacking at a position at which the interval in the peripheral direction between
the adjacent radial slats 25b, 25b finally reaches approximately Q/2. The remaining
radial slats 25a, 25c are extended to the center of the circular slats 24 as they
are. Thus, the intervals in the peripheral direction between the radial slats 25a,
25c are made sequentially smaller. Further, ends of the radial slats 25c are lacking
at a position at which the interval in the peripheral direction between the adjacent
radial slats 25a, 25c reaches approximately Q/2. In this manner, lacking portions
are repeatedly formed under the condition described above until the remaining radial
slat 25a is extended to the center of the circular slats 24.
[0029] That is, the radial slats 25b are disposed up to the position of a concentric circle
R1 and ends thereof located forward of the position are lacking. Further, the radial
slats 25c are disposed up to the position of a concentric circle R2 and ends thereof
located forward of the position are lacking. Then, the radial slats 25a, 25a are disposed
at the position of an innermost periphery at predetermined intervals and the ends
thereof forward of the position are lacking.
[0030] Note that only radial slats 25a are disposed on an concentric circle R3 that is located
one pitch inward of the ends of the radial slats 25b disposed on the concentric circle
R1 and no radial slat 25c is disposed thereon. Radial slats 25c are disposed every
other pitch from a concentric circle R4 located one pitch inward of the concentric
circle R3.
[0031] That is, although the radial slats 25a, 25c and radial slats 25b are disposed alternately
from the outermost periphery of the circular slats 24, the radial slats 25a and radial
slats 25c are disposed alternately from the concentric circle R1 on which the radial
slats 25b are lacking for the first time to the center of the circular slats 24.
[0032] As a result, although the intervals between the radial slats 25 on the same concentric
circles are made gradually smaller from the outermost periphery of the circular slats
24 to the center thereof, the intervals between the radial slats 25a-25a on the concentric
circle R3 located one pitch inwardly of the ends of the radial slats 25b where they
are lacking for the first time are increased approximately equal to the intervals
Q on the outermost periphery. Then, the intervals between the radial slats 25c and
25a disposed alternately from the concentric circle R4 located one pitch inward of
the concentric circle R3 to the center are made sequentially smaller.
[0033] As described above, since the intervals between the radial slats 25 that secure necessary
strength as the fan guard 20 can be set larger, the number of the radial slats 25
having a large resistance to an air flow can be reduced. Specifically, the number
of the radial slats used in the fan guard 20 is set as shown in Table which will be
described below.
[0034] Accordingly, the fan guard 20 is arranged in a mode which is in agreement with the
intensity of an air flow blown off from the propeller fan 15f and corresponds to the
blowing-off characteristics of the outdoor blower 15, thereby the ventilation resistance
of the fan guard 20 is reduced and the air blasting characteristics of the outdoor
blower 15 are greatly improved, so that a heat exchange performance can be greatly
improved.
[0035] FIG. 4 shows a fan guard 30 as a modification of the first embodiment described above.
The fan guard 30 is simultaneously provided with two sets of the fan guards 20 explained
above in FIG. 3A, and the fan guards 20 confront with each other so that they are
disposed symmetrically with respect to an up/down direction.
[0036] The inner structure (not shown) of the fan guard 30 is basically similar to that
of the fan guard 20 explained in FIG. 1. Since, however, the fan guard 30 is employed
in an outdoor unit of a relatively large air conditioner, two sets of outdoor heat
exchangers are disposed in confrontation with the upper and lower fan guards or one
set of a large outdoor heat exchanger that extends to the upper and lower fan guards
is disposed. Further since outdoor fans are disposed in confrontation with the upper
and lower fan guards, an operation effect similar to that described above can be obtained.
[0037] FIG. 5 shows a result of measurement of change in operation noise to quantities of
supplied air in the outdoor unit having the fan guard 20 shown in FIG. 3A and in the
outdoor unit having the conventionally arranged fan guard 3 described previously in
FIG. 13.
[0038] It can be found that when the same outdoor blower 15 is used, a degree of operation
noise to the quantity of supplied air in the fan guard of the present invention N1
is lower than the fan guard of the conventional arrangement N2.
[0039] FIG. 6A shows a fan guard 40 as a modification of the first embodiment. Note that,
in FIG. 6A, circular slats 44 are disposed in correspondence to the circular slats
24 in FIGS. 3A and 3B described above, and radial slats 45 are disposed in correspondence
to the radial slats 25 in FIGS. 3A and 3B.
[0040] That is, the respective radial slats 45 are disposed with respect to the circular
slats 44 formed concentrically under the same condition as that of the radial slats
25 described above. However, all the radial slats 45 are disposed in a state in which
they are inclined a predetermined angle with respect to the center of the circular
slats 44.
[0041] The fan guard 40 arranged as described above also has precisely the same effect as
that of the fan guard 20 described above.
[0042] Further, although all the radial slats 45 are formed in a state in which they are
inclined the predetermined angle with respect to the center of the circular slats
44, the present invention is not limited thereto, and they may be appropriately inclined
in a different direction and formed in, for example, a spiral shape in its entirety.
[0043] FIG. 6B shows a fan guard 50 as another modification of the first embodiment. The
fan guard 50 is composed of a first slat portion 51 and a second slat portion 52.
The first slat portion 51 is separated from the second slat portion 52 by a predetermined
pitch circle having a diameter approximately half that of the circle of an outermost
periphery, and the first slat portion 51 is located on the outermost periphery side,
and the second slat portion 52 is located on an inner periphery side. In the first
slat portion 51, concentric circular slats 53 are disposed as well as radial slats
54 are disposed toward the center of the predetermined pitch circle from the outermost
periphery of the circular slats 53 to the pitch circle at equally spaced intervals
similar to conventional intervals. In the second slat portion 52, concentric circular
slats 55 are disposed as well as radial slats 56 are disposed alternately to the concentric
circles between the concentric circular slats 55 from the position of the pitch circle
to the center thereof. The fan guard 50 has definitely the same effect as that of
the fan guard 20 described above.
[0044] FIG. 7A shows a fan guard 60 as a second example. The fan guard 60 is composed of
a plurality of circular slats 64, which are disposed concentrically at entirely the
same pitch from an outermost periphery to a center, and radial slats 65 disposed so
as to intersec the circular slats 64. However, the radial slats 65 exhibits a modified
radial state according to a condition under which the radial slats 65 are disposed
as described later.
[0045] The radial slats 65 are disposed on the concentric circles between the circular slats
64 at equally spaced intervals. However, the number of the radial slats 65 on the
concentric circles is gradually reduced one piece at every pitch of the concentric
circles from the outermost periphery of the circular slats 64 to the center thereof.
[0046] With this arrangement, the radial slats 65 are composed of a straight line portion
65a formed straight from the outermost periphery of the circular slats 64 to the center
thereof, parabolic portions 65b formed on both the sides of the straight line portion
65a in a parabolic state, and alternate portions 65c formed alternately on the concentric
circles between the circular slats 64 in the portion other than the straight line
portion 65a and the parabolic portions 65b.
[0047] In FIG. 7B, it will be easier to specifically explain the number of the radial slats
65 in an outer peripheral direction from the center of the circular slats 64. One
radial slat 65 is disposed straight from the center of the circular slats 64 to the
outermost periphery thereof and acts as the straight line portion (reference radial
slat) 65a. Seven radial slats 65 in total including the straight line portion 65a
are disposed at equally spaced intervals on a concentric circle R7 between the circular
slats 64 which is displaced one pitch in the outer peripheral direction from the center
of the circular slats 64. Further, eight radial slats 65 in total including the straight
line portion 65a are disposed at equally spaced intervals on a concentric circle R8
displaced one pitch in the outer peripheral direction from the concentric circle R7.
[0048] Further, nine radial slats 65 in total including the straight line portion 65a are
disposed at equally spaced intervals on a concentric circle R9 displaced one pitch
in the outer peripheral direction from the concentric circle R8, and ten radial slats
65 in total including the straight line portion 65a are disposed at equally spaced
intervals on a concentric circle R10 displaced one pitch in the outer peripheral direction
from the concentric circle R9.
[0049] As described above, each time a concentric circle is displaced one pitch in the outer
peripheral direction, one piece of a radial slat is added to the number of radial
slats 65 disposed on the concentric circle. In FIG. 7B, 28 radial slats 65 in total
including the straight line portion 65a are disposed at equally spaced intervals on
a concentric circle R28 located on the outermost periphery side and formed in a perfect
circular shape. Further, on concentric circles formed in an arc shape outward of the
concentric circle R28, the radial slats 65 are disposed at intervals that are set
at the same rate of change.
[0050] As a result, the radial slats 65 are composed of the straight line portion 65a formed
straight from the outermost periphery of the circular slats 64 to the center thereof,
the parabolic portions 65b disposed on both the sides of the straight line portion
65a, and the alternate portions 65c other than the straight line portion 65a and the
parabolic portions 65b.
[0051] Accordingly, the fan guard 60 is arranged in a mode which is in agreement with the
intensity of an air flow blown off from the propeller fan 15f and corresponds to the
blow-off characteristics of the outdoor blower 15, thereby the ventilation resistance
of the fan guard 60 is reduced and the blast characteristics of the outdoor blower
15 are greatly improved, so that heat exchange performance can be greatly improved.
[0052] FIG. 8 shows a fan guard 70 as a modification of the second example described above.
The fan guard 70 is simultaneously provided with two sets of the fan guards 60 described
above in FIG. 7A, and the fan guards 60 confront with each other so that they are
disposed symmetrically with respect to an up/down direction.
[0053] The inner structure (not shown) of the fan guard 60 is basically similar to that
of the fan guard 20 explained in FIG. 1. Since, however, the fan guard 60 is employed
in an outdoor unit of a relatively large air conditioner, two sets of heat exchangers
are disposed in confrontation with the upper and lower fan guards or one set of a
large outdoor heat exchanger that extends to the upper and lower fan guards is disposed.
Further, since outdoor fans are disposed in confrontation with the upper and lower
fan guards, an operation effect similar to that described above can be obtained.
[0054] FIG. 9 shows a fan guard 80 as another modification of the second example. The fan
guard 80 includes a straight portion 85a used as a reference similarly to the above
reference radial slat, parabolic portions 85b, and alternate portions 85c, and only
a part of the alternate portions 85c is modified.
[0055] Specifically, seven radial slats 85 in total including the reference radial slat
85a are disposed on a concentric circle R7 at equally spaced intervals, and radial
slats 85 are disposed at enlarged intervals on a concentric circle R8 displaced one
pitch externally of the concentric circle 7R at portions corresponding to alternate
portions 85c.
[0056] Likewise, radial slats 85 are disposed at expanded intervals also on concentric circles
R9 and R10 at portions corresponding to the alternate portions 85. In FIG. 9, hatched
portions show the portions where the intervals of the radial slats 85 are enlarged.
[0057] Accordingly, since the fan guard 80 does not need the number of radial slats 85 whose
strength exceeds the strength required to the fan guard 80, the number of radial slats
85 can be reduced to an ultimately necessary number, thereby the ventilation resistance
of the fan guard 80 can be reduced and the air blasting characteristics of the outdoor
blower 15 can be greatly improved, so that a heat exchange performance can be greatly
enhanced.
[0058] Table 1 shows the number of radial slats on each concentric circle between circular
slats when the radius of the outermost periphery of a circular slat is shown by, for
example, La and the radii of circular slats are reduced in a sequence of Lb, Lc, Ld,
..., Lw to the center thereof. Accordingly, the number of radial slats in the arrangements
of the fan guards described heretofore based on the drawings does not always correspond
to the number of radial slats in Table 1.
[0059] In the column of conventional example in Table 1, since 32 pieces, for example, of
radial slats are necessary on all the concentric circles between circular slats from
the outermost periphery La to the center Lw, the number of radial slats amounts to
736 pieces.
[0060] In contrast, the number of radial slats 25 shown in the column of the fan guard 20
is set by alternately disposing the radial slats 25 as described above in FIG. 3A.
The number of radial slats 25 from the outermost periphery La of the circular slats
24 to the center Lw thereof is divided into, for example, three kinds of groups, that
is, a group of 24 pieces, a group of 12 pieces, and a group of 6 pieces. Thus, the
number of radial slats 25 amounts to 390 pieces in total, and the ratio of the number
of radial slats 25 to the number of radial slats in the conventional structure of
736 pieces is 0.54.
[0061] The number of radial slats 65 shown in the column of the fan guard 60 is reduced
one piece on every concentric circle between circular slats 64 from the outermost
periphery La to the center Lw, as explained in FIG. 7A previously.
[0062] Although 32 pieces of radial slats are necessary on the outermost periphery La, since
the number of radial slats is reduced one piece at every one pitch, the number of
them is reduced to 10 pieces on a concentric circle on which the number of radial
slats is minimized. Thus, the total number of radial slats amounts to 483 pieces that
are greatly smaller than those of the conventional example, although the total number
is larger than that of the first embodiment.
[0063] FIGS. 10A to 10D are views showing an example of specific shapes of the circular
slats and the radial slats. Note that although these shapes can be applied to all
the circular slats 24, 44, 54, 64, 84 and to all the radial slats 25, 45, 55, 56,
65, 85 of the fan guards 20 to 80 described above, explanation will be made here as
to the circular slats 24 and the radial slats 25 of the fan guard 20.
[0064] That is, the circular slats 24 are disposed in parallel with each other at predetermined
intervals, the radial slats 25 are disposed in a direction where they are perpendicular
to the circular slats 24. The circular slats 24 have a sectional shape formed in a
substantially flat shape or in a substantially blade shape. Thus, ventilation resistance
is reduced between the circular slats 24 as well as an increase in noise due to exfoliation
of air flow is suppressed, thereby the air blasting characteristics can be greatly
improved.
[0065] Further, the radial slats 25 have a sectional shape formed in a circular, substantially
flat or substantially blade shape. Therefore, the strength of the fan guard 20 can
be increased without almost increasing the ventilation resistance thereof, and the
sectional dimension of the circular slats 24 can be suppressed thereby.
[0066] FIGS. 11A and 11B are views showing examples of a technical reference. FIG. 11A shows
a front surface side of a cabinet 10, wherein a fan guard 90 is fitted to an outlet
port 18. The fan guard 90 is composed of a plurality of slats molded integrally using
a synthetic resin material.
[0067] Specifically, the slats are composed of a plurality of circular slats 94, which are
disposed concentrically at a predetermined pitch from a center to an outermost periphery,
and a plurality of radial slats 95, which intersect the circular slats 94 and are
disposed radially from the center of the circular slats 94 to the outermost periphery
thereof.
[0068] Although it is needless to say that the intervals between the radial slats 95, which
are located adjacent to each other, are gradually increased from the center of the
circular slats 94 to the outermost periphery thereof (gradually reduced from the outermost
periphery of the circular slats 94 to the center thereof), these radial slats 95 are
lacking at the ends thereof which confront the center of the circular slats 94 at
predetermined positions.
[0069] Next, an arrangement of the lacking end portions of the radial slats 95 will be described
in detail. It is assumed that the interval between adjacent radial slats 95 is shown
by m which are located on the perfectly circular outermost periphery Ps of the circular
slats 94. When the radial slats 95 are extended toward a center Z from the outermost
periphery Ps of the circular slats 94 acting as a reference, the interval between
the adjacent radial slats 95 is made gradually smaller than the interval m.
[0070] Then, there is a position where the interval between the adjacent radial slats 95
is set to m/2 on the circular slat 94 at a predetermined position. At this position,
an end of one of the radial slats 95 is lacking, and the portion of the radial slat
95 located forward of the lacking end is thinned out.
[0071] The other radial slat 95 is extended as it is to the center of the circular slats
94. Thus, since the other radial slat 95 is located adjacent to the radial slat 95
extended previously without lacking, the interval therebetween is made sequentially
smaller.
[0072] Finally, the interval between the adjacent radial slats 95 is set to m/2 at a predetermined
position of the circular slats 94. Then, an end of one of the radial slats 95 is lacking
at the predetermined position, and the portion of the radial slat 95 located forward
of the lacking end is thinned out. In this manner, lacking portions are repeatedly
formed under the condition described above until the remaining radial slats 95 are
extended to the center of the circular slats 94.
[0073] Further, this will be specifically described based on FIG. 11B. Reference radial
slats 95s, which extend from the center of the circular slats 94 to the outermost
periphery thereof and intersect with each other vertically and-horizontally, are disposed,
and a radial slat located at an intermediate portion between the reference radial
slats 95s (that is, located at a position displaced 45° from the reference radial
slats S) is denoted by reference numeral 95a.
[0074] Radial slats 95b, 95b are disposed on both the sides of the radial slat 95a, and
further radial slats 95c, 95c are disposed on both the sides of the radial slats 95b,
95b. The radial slats 95a, 95b, and 95c are disposed on the perfectly circular outermost
periphery Ps of the circular slats 94 at intervals m.
[0075] Although these radial slats 95a, 95b, and 95c are extended from the outermost periphery
of the circular slats 94 to the center thereof, the intervals between the radial slat
95a and the radial slats 95b and the interval between the radial slat 95b and the
radial slats 95 are set to m/2, respectively at the position Pa of a predetermined
pitch circle of the circular slats 94
[0076] At this position, the radial slat 95a and the radial slats 95c remain as they are,
ends of the radial slats 95b on both the sides of the radial slat 95a are lacking,
and the portions of the radial slats 95b located forward of the lacking ends are thinned
out. Since the radial slats 95a and 95c are further extended, the radial slat 95a
is located adjacent to the radial slats 95c, and the interval therebetween is made
gradually smaller.
[0077] At the position Pb of a predetermined pitch circle of the circular slats 94, the
interval between the radial slat 95a and the radial slats 95c and the interval between
the radial slats 95c and the radial slat 95s are set to m/2, respectively. Thus, an
end of the radial slat 95c is lacking at this time, and the radial slats 95a and 95s
are further extended.
[0078] Accordingly, the radial slat 95a is located adjacent to the reference radial slats
95s at the portion forward of the position Pb, thereby the interval therebetween is
made gradually smaller. At the position Pc of a predetermined pitch circle of the
circular slats 94, the interval between the radial slats 95a and 95s is set to m/2.
At this time, an end of the radial slat 95a is lacking, and only the reference radial
slats 95s exist on the center side forward of the lacking end.
[0079] With the above arrangement, the fan guard 90 is arranged in a fan guard mode which
is in agreement with the intensity of air flow blown off from the propeller fan 15f
and corresponds to the blowing-off characteristics of the outdoor blower 15 by lacking
and thinning off of the radial slats 95 which are not necessary in strength, thereby
the ventilation resistance of the fan guard 90 is reduced and the air blasting characteristics
of the outdoor blower 15 are greatly improved, so that heat exchange performance can
be greatly improved.
[0080] Note that the number of radial slats 95 described in the column of the fan guard
90 of Table 1 is as described below. That is, the number of radial slats 25 on the
outermost periphery La is 32 pieces that is as many as that of the conventional example.
However, since ends of the radial slats are lacking on predetermined pitch circles,
the number of radial slats 25 is reduced to 16 pieces at some mid point that is half
the 16 pieces, and further reduced to 8 pieces in the vicinity of the center that
is half the 16 pieces, thereby only 520 pieces in total of the radial slats 25 are
necessary. Accordingly, the number of radial slats can be greatly reduced as compared
with that of the conventional example.
[0081] FIG. 12 shows a fan guard 99 as a modification of the first embodiment described
above. The fan guard 99 is simultaneously provided with two sets of the fan guard
90 explained above in FIG. 11A, and the fan guards 90 confront with each other so
that they are disposed symmetrically with respect to an up/down direction.
[0082] The inner structure (not shown) of the fan guards 90 is basically similar to that
of the fan guard 20 explained in FIG. 1. Since, however, the fan guard 99 is employed
in an outdoor unit of a relatively large air conditioner, two sets of heat exchangers
are disposed in confrontation with the upper and lower fan guards or one set of a
large outdoor heat exchanger that extends to the upper and lower fan guards is disposed.
Further since outdoor fans are disposed in confrontation with the upper and lower
fan guards, an operation effect similar to that described above can be obtained.
Industrial Applicability
[0083] As explained above, the present invention is advantageous in the technical field
of an air conditioner because the invention achieves such effects that a ventilation
area can be increased in an outlet port of a cabinet while increasing the strength
of a fan guard attached to the outlet port and that air blasting performance can be
greatly improved by suppressing ventilation resistance.