EP0763696A1

EP0763696A1 - Indoor unit of air conditioner

Info

Publication number: EP0763696A1
Application number: EP96114641A
Authority: EP
Inventors: Takashi Matsushita Elec. Ind. Co. Ltd. Sugio; Hirokazu Matsushita Elec. Ind. Co. Ltd. Sakai; Shigeru Matsushita Elec. Ind. Co. Ltd. Nariai; Teruo Matsushita Elec. Ind. Co. Ltd. Tosha
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1995-09-13
Filing date: 1996-09-12
Publication date: 1997-03-19
Also published as: CN1151494A; JPH0979602A

Abstract

Independent heat exchangers (17a, 17b) are spaced from each other by a suitable distance as inclined to decrease a distance between the upper portions thereof. An elongate plate (26) bridges a gap between the upper portions of the heat exchangers. A cross-flow fan (18) is disposed at place in an opening between the lower portions of the heat exchangers whereas a heater is disposed directly under the elongate plate (26).

Description

TECHNICAL FIELD

The present invention relates to an indoor unit of an air conditioner, and more particularly to a structure of an air flow circuit in a flowthrough-type air conditioner.

BACKGROUND ART

Responding to a demand for a higher performance of air conditioners, there has recently been invented an indoor unit of such a construction as disclosed in Japanese Unexamined Patent Publication No.58-98521 (1983). The construction will be described as below with reference to Fig.15. In Fig. 15, an indoor unit 201 comprises an air flow passage defined between inlet ports 202A and 202B, and an outlet port 203. Within the air flow passage, heat exchangers 204A and 204B are arranged in an inverted-V form while a cross-flow fan 205 is disposed relative to the lower portions of the heat exchangers 204A and 204B so that an air subject to a heat exchanging process is to be sent to the outlet port 203. Drain pans 206 serve to receive condensation dropping from the respective heat exchangers 204A and 204B while constituting a portion of the air flow passage.
The indoor unit 201 of the aforementioned construction is advantageous in that the heat exchangers 204A and 204B, arranged in an inverted-V form, can achieve a notable improvement in the capacity as compared to the older arrangement of the heat exchangers.
More recently, there are increasing examples wherein a heater of a relatively small capacity is disposed downstream of the heat exchangers, the heater being utilized for re-heating during a dehumidifying operation or as an auxiliary heat source of a heat pump system because such a heater is simple to use and highly effective.
Unfortunately, in the aforementioned indoor unit including the two heat exchangers 204A and 204B, only a substantially triangular space surrounded by the cross-flow fan 205 and the heat exchangers 204A and 204B allows for the installation of the heater. It is extremely difficult to contain the heater and the associated components thereof in such a space and to prevent an increase in the air flow resistance and the production of noise.
Furthermore, while the heater is ON, an air flow downstream of the heater has a different density from the ambient air flow due to the temperature difference. Accordingly, if the heater is close to the cross-flow fan 205, a notable abnormal sound occurs additionally to normal noises as the air flow downstream of the heater enters the cross-flow fan 205.

DISCLOSURE OF THE INVENTION

For solving the foregoing problems, an indoor unit of an air conditioner according to the invention comprises an air flow passage defined between a front cover and a main body frame and extending toward an outlet port at the lower end thereof, the front cover including inlet ports at the top and the front surfaces thereof, a cross-flow fan disposed within the air flow passage and including an impeller comprised of a plurality of blades arranged in a column-like form, heat exchangers disposed at places upstream of the cross-flow fan on a front and a rear side, respectively, and a stabilizer and a rear guider disposed at places on a front side and a rear side, respectively, and defining therebetween a diffuser extending from the cross-flow fan toward the outlet port, the indoor unit characterized in that both the heat exchangers are independently disposed as spaced from each other by a suitable distance and inclined in a manner to decrease a distance between the upper portions thereof, that an elongate plate is provided for bridging a gap between the upper portions of the heat exchangers while the cross-flow fan is located at place in an opening defined between the lower portions of the heat exchangers, and that a heater is disposed directly under the elongate plate.
With the above arrangement, the space surrounded by the two heat exchangers and cross-flow fan is expanded to a substantially trapezoid-shaped space which provides a sufficient room to readily accommodate the heater as well as to allow the heater to be spaced from the cross-flow fan. As a result, an air flow downstream of the heater having a different density from the ambient air flow may be diffused by the time it enters the cross-flow fan so that the level of an interference noise can be reduced, which is caused by the air flow downstream of the heater entering the cross-flow fan.
In a more preferred mode of the invention, the indoor unit is characterized in that a heater support plate for supporting the heater is located directly under the elongate plate while substantially trapezoid-shaped side plates are disposed at places on opposite sides with respect to the direction of the rotary axis of the cross-flow fan thereby interconnecting the heat exchangers at the respective side-end portions thereof opposing to each other, whereby the opposite ends of the heater support plate are fixedly retained by the side plates.
With this arrangement, the heater extending transversely of the air flow passage may be fixedly retained in a stable and static state by means of the heater support plate augmenting the strength of the heater. On the other hand, the heater support plate has the opposite ends thereof stably retained by the heat exchangers by means of the side plates, thus securing a sufficient strength against the air flow.
In a more preferred mode hereof, the indoor unit is characterized in that a first connection wire from one end of the heater extends through an aperture in one of the side plates opposing the one end of the heater whereas a second connection wire from the other end of the heater is reversed along the heater support plate to be extended through the aperture in the aforesaid side plate along with the first connection wire, the second connection wire having the reversed portion thereof fixedly supported by the heater support plate.
With this arrangement, the second connection wire extended transversely of the air flow passage may be fixedly retained in a static state by the heater support plate intimately contacted therewith. This reduces the air flow resistance while eliminating noises which occur as the air flow is cut through by the wires. Additionally, the integrity of the connection wires and heater support plate is enhanced for an easier handling thereof.
In a more preferred mode, the indoor unit is characterized in that a heater support plate for supporting the heater is located directly under the elongate plate while support plates perpendicular to the rear guider are disposed at places on opposite sides with respect to the direction of the rotary axis of the cross-flow fan to thereby fixedly retain the heater support plate at the opposite ends thereof.
With this arrangement, the heater extending transversely of the air flow passage may be fixedly retained in a stable and static state by means of the heater support plate augmenting the strength of the heater. On the other hand, the heater support plate has the opposite ends thereof stably retained by the rear guider by means of the support plates, thus securing a sufficient strength against the air flow.
In a more preferred mode hereof, the indoor unit is characterized in that a first connection wire from one end of the heater extends through an aperture in one of the support plates opposing the one end of the heater whereas a second connection wire from the other end of the heater is reversed along the heater support plate to be extended through the aperture in the aforesaid support plate along with the first connection wire, the second connection wire having the reversed portion thereof fixedly supported by the heater support plate.
With this arrangement, the second connection wire extended transversely of the air flow passage may be fixedly retained in a static state by the heater support plate intimately contacted therewith. This reduces the air flow resistance while eliminating noises which occur as the air flow is cut through by the wires. Additionally, the integrity of the connection wires and heater support plate is enhanced for an easier handling thereof.
In a more preferred mode hereof, the indoor unit is characterized in that an even number of the heaters are disposed in parallel directly under the elongate plate with connection wires extending from the opposite ends of each heater connected in series.
With this arrangement, only the heaters having a rigidity extend transversely of the air flow in the air flow passage whereas a pair of the connection wires serving as an input end for the group of heaters are both located on one side of the heaters and therefore, no connection wire extends transversely of the air flow passage. Accordingly, there is no turbulent air flow caused by the contact between the air flow and connection wires, and thus is reduced the occurrence of noises caused by the turbulent air flow. Since the connection wires do not extend transversely of the air flow, the heater support plate for retaining the connection wires is not required, which contributes to a reduced air flow resistance and a reduced number of the components.
In a more preferred mode hereof, the indoor unit is characterized in that at least one of an abnormality detection means for detecting abnormal states of the heater, such as overcurrent, overheat or the like, and a protection device for interrupting the current is fixed to the heater support plate.
This arrangement enables the unification of the heater and abnormality detection means or protection device, which are the associated component to the heater, thus facilitating an operation for attaching/removing such components to the heater.
In a more preferred mode hereof, the indoor unit is characterized in that a cap-like cover is provided for covering the top portion of the abnormality detection means or protection device.
This arrangement provides a protection of the abnormality detection means and protection device from drops of condensation which might otherwise fall thereupon from the heat exchangers. Additionally, the arrangement streamlines the flow of air around the abnormality detection means and protection device for reducing the level of the noise.
In a more preferred mode hereof, the indoor unit is characterized in that the heater is mounted to the heater support plate in a manner to maintain a constant distance between the heater and the heater support plate along the direction of air flow or to progressively decrease such a distance toward the downstream side.
In the above arrangement, the streams of air penetrating the two heat exchangers flow along the vertical direction or so flow as to converge toward the downstream side and therefore, the heater and heater support plate arranged in the aforementioned position may conform with the direction of the air flow. Thus, the flow resistance decreases to reduce the width of the air flow downstream of the heater so that the noise level is lowered.
In a more preferred mode hereof, the indoor unit is characterized in that an obstacle for stirring an air flow downstream of the heater is disposed directly under the heater.
With the above arrangement, the air flow downstream of the heater having a different density from the ambient air flow due to a temperature difference may be diffused by the obstacle so as to reduce the density difference from the ambient air flow as well as to increase the width of the air flow into the cross-flow fan. This prevents the occurrence of a notable abnormal sounds caused by the downstream-side air flow entering the cross-flow fan.
In a more preferred mode hereof, the indoor unit is characterized in that a plate-like obstacle directly under the heater is inclined relative to the direction of air flow.
The above arrangement assures the prevention of an increase in the flow resistance of the obstacle itself while maintaining an en effect to prevent the occurrence of the abnormal sound caused by the downstream-side air flow entering the cross-flow fan.
In a more preferred mode hereof, the indoor unit is characterized in that a plate-like obstacle directly under the heater is fixed to the heater support plate.
The above arrangement facilitates an operation for mounting the obstacle.
In a more preferred mode hereof, the indoor unit is characterized in that a plate-like obstacle directly under the heater is integrally formed with the heater support plate.
The above arrangement facilitates the fabrication and mounting operation of the obstacle.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1 is a sectional view of a first embodiment of the invention;
Fig.2 is a perspective view of a second embodiment hereof;
Fig.3 is a perspective view of a third embodiment hereof;
Fig.4 is a perspective view of a fourth embodiment hereof;
Fig.5 is a perspective view of a fifth embodiment hereof;
Fig.6 is a perspective view of a sixth embodiment hereof;
Fig.7 is a perspective view of a seventh embodiment hereof;
Fig.8 is a perspective view of an eighth embodiment hereof;
Fig.9 is a sectional view of a ninth embodiment hereof;
Fig.10 is a sectional view of a tenth embodiment hereof;
Fig.11 is a graphical illustration of the frequency analysis of the tenth embodiment hereof;
Fig.12 is a sectional view of an eleventh embodiment hereof;
Fig.13 is a perspective view of a twelfth embodiment hereof;
Fig.14 is a perspective view of a thirteenth embodiment hereof; and
Fig.15 is a sectional view of the prior art construction.

EMBODIMENTS

Description will be given on the embodiments hereof with reference to the drawings. Fig.1 is a sectional view of an indoor unit of an air conditioner of the invention. In Fig. 1, an indoor unit 10 comprises an inlet port 11 in the upper portion and top surface thereof, an outlet port 12 at the lower portion thereof and an air flow passage 13 defined between the inlet port 11 and outlet port 12. The air flow passage 13 contains therein a removable air filter 16 inserted along the inner surface of a front cover 14 to a place on the top side of a main body frame 15, heat exchangers 17a and 17b located at the front and rear sides, respectively, and a cross-flow fan 18 inside of a space surrounded by the heat exchangers 17a and 17b. The cross-flow fan 18 comprises a plurality of unitized bodies of impellers combined along the rotary axis, the unitized body of impeller being formed of a plurality of blades 19 arranged in a collum-like form.
In the air flow passage 13 downstream of the cross-flow fan 18, there are disposed a stabilizer 21 close to and opposite to the cross-flow fan 18, and a rear guider 23 cooperating with the stabilizer 21 to define a diffuser 22 extending from the cross-flow fan 18 to the outlet port 12. A portion of the rear guider 23 and the stabilizer 21 each form a drain pan 24 for receiving condensation dropping from the heat exchangers 17a and 17b. Disposed at the outlet port 12 is a vertical guide vane 25 for regulating the vertical direction of an air flow discharged into a room.
The heat exchangers 17a and 17b are independently disposed at places spaced by a suitable distance as inclined in a manner to decrease a distance between the upper portions thereof. An elongate plate 26 bridges a gap between the upper portions of the heat exchangers 17a and 17b thereby interconnecting them. The cross-flow fan 18 is located within an opening between the lower portions of the heat exchangers 17a and 17b whereas a heater 27 is located directly under the elongate plate 26. The heater 27 is fixedly retained by a heater supporting plate 29 by means of a fixing jig 28.
In this embodiment, the heater 27 is employed for dehumidification and as a supplementary heat source during the operation of a heat pump. Herein, description will be given particularly to the dehumidification operation. During the dehumidification operation, the heat exchangers 17a and 17b operate as an evaporator. More specifically, a sucked room air is cooled as penetrating the heat exchangers 17a and 17b of a lower temperature and is also lowered in the absolute humidity as moisture contained in the air is condensed on the surface of the heat exchangers 17a and 17b. In a normal cooling operation, the air having passed through the heat exchangers 17a and 17b is directly discharged.
However, if the heater 27 is provided downstream of the heat exchangers 17a and 17b, the air having passed through the heat exchangers 17a and 17b is raised only in the temperature but the absolute humidity thereof is not affected by the heater. Hence, having passed the heater 27, the air has a temperature near the room temperature but a low humidity relative to the room air, and thus is obtained a dehumidified air.
Considering such a role of the heater 27 during the dehumidification operation, the heater 27 is required to be positioned downstream of the heat exchangers 17a and 17b. Incidentally, a space downstream of the cross-flow fan 18 is not sufficient to accommodate the heater and besides a fear exists for that an air heated by the heater, disposed downstream of the fan, will rise along the air flow passage after the fan is stopped. Accordingly, it is most suitable to locate the heater 27 in the space surrounded by the heat exchangers 17a and 17b and cross-flow fan 18.
When the heater 27 is installed in the space surrounded by the heat exchangers 17a, 17b and cross-flow fan 18, the heater 27 must be spaced as far as possible from the cross-flow fan 18 in order to prevent an increase in the level of noise caused by the interference between the heater 27 and cross-flow fan 18.
In such a case, the heat exchangers 17a and 17b may be spaced by way of the elongate plate 26, as proposed by this embodiment, to thereby expand a space surrounded by the heat exchangers 17a, 17b and cross-flow fan 18 into a trapezoidal form, which provides a sufficient space to readily accommodate the heater 27. Furthermore, the heater 27 can be spaced from the cross-flow fan 18. As a result, the air flow downstream of the heater 27 having a different density relative to the ambient air flow may be diffused by the time it enters the cross-flow fan 18. Hence, the interference noise caused by the air flow downstream of the heater 27 entering the cross-flow fan 18 may be reduced.

EMBODIMENT 2

Now referring to Fig.2, a second embodiment hereof will be described. It is to be noted that the same components as those of Embodiment 1 will be represented by the same reference characters. In Fig. 2, two heat exchangers 17a and 17b are provided with substantially trapezoid-shaped side plates 31 for fixing the both relative to each other as well as for securing the both to a main body frame 15. The side plates 31 are disposed at places on opposite sides with respect to the direction of the rotary axis of a cross-flow fan 18, as spanning a substantially triangular gap defined between the heat exchangers 17a and 17b. A heater support plate 29 for supporting the heater 27 is secured to the side plates 31 with the opposite ends thereof inserted into apertures 32 defined in the side plates 31, respectively.
Such a mode facilitates the fixing of the heater 27 and the heater support plate 29 for supporting the heater. As compared to other fixing methods wherein, for example, the heater 27 is suspended from an elongate plate 26, it is easier to maintain the strength of the heater support plate 29 as well as to attach/remove the heater 27 or heater support plate 29.

EMBODIMENT 3

Now referring to Fig.3, a third embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 and 2 are represented by the same reference characters. In Fig. 3, a first connection wire 33 from one end of a heater 27 extends through an aperture 32 in a side plate 31 to be connected to a supply section 35. On the other hand, a second connection wire 34 from the other end of the heater is reversed to be extended through the aperture 32 in the side plate 31 along with the first connection wire 33, with the reversed portion thereof fixedly supported by a heater support plate 29.
Such a mode ensures that the second connection wire 34 is positively secured while accomplishing a reduced air flow resistance by means of the second connection wire 34 intimately contacted with the heater support plate 29. Additionally, the integrity of the second connection wire 34, heater 27 and heater support plate 29 is enhanced to thereby allow these components to be assembled or repaired as one block.

EMBODIMENT 4

Now referring to Fig.4, a fourth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 3 are represented by the same reference characters. In the figure, support plates 36 perpendicular to a rear guider 23 are disposed at places on opposite sides with respect to the direction of the rotary axis of a cross-flow fan 18. A heater support plate 29 is fixedly retained by the support plates 36 with the opposite ends thereof inserted in apertures in the respective support plates 36.
Such an arrangement facilitates the fixing of the heater 27 and heater support plate 29 for supporting the heater, thus contributing an easier operation for attaching or removing them.

EMBODIMENT 5

Now referring to Fig.5, a fifth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 4 are represented by the same reference characters. In Fig. 5, a first connection wire 33 from a heater 27 extends through an aperture 37 in a support plate 36 to be connected with a supply section 35. On the other hand, a second connection wire 34 is reversed to be extended through the aperture 37 in the support plate 36 for connection with the supply section 35.
Such a mode ensures that the second connection wire 34 is positively secured while accomplishing a reduced air flow resistance by means of the second connection wire 36 intimately contacted with a heater support plate 29.

EMBODIMENT 6

Now referring to Fig.6, a sixth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 5 are represented by the same reference characters. In Fig. 6, there are provided two heaters 27 connected in series whereby either of the heaters 27 may replace the second connection wire 34 in the aforementioned arrangement. Unlike the connection wire 34, the heater 27 has a high rigidity and therefore, a heater support plate 29 is eliminated.
Although this embodiment employs two heaters 27, it is obvious to those skilled in the art that an equivalent effect may be attained by providing an even number of heaters.

EMBODIMENT 7

Now referring to Fig.7, a seventh embodiment hereof will be described. It is to be noted that the same components as those in Embodiments 1 through 6 are represented by the same reference characters. In Fig. 7, fixed to a heater support plate 29 are a temperature OLP 38 and a fuse 39. The temperature OLP 39 operates to interrupt the current upon detection of overheat due to the abnormal operation of a heater 27 whereas the fuse 30 operates to interrupt the current upon detection of overcurrent due to the abnormal operation of the heater 27.
Such a mode enables it to unify the temperature OLP 38 and fuse 39, constituting a part of an abnormality detection means and protection device, with the heater support plate 29 and heater 27 in one block, which facilitates the assembly or repair work thereof.
Incidentally, the temperature OLP 38 disposed in close vicinity of the heater 27 assures the detection of abnormality due to the overheat of the heater 27.

EMBODIMENT 8

Now referring to Fig.8, an eighth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 7 are represented by the same reference characters. In Fig. 8, a cap-like cover 40 is mounted atop a temperature OLP 38 fixed to a heater support plate 29 for covering the top portion of the temperature OLP 38.
With this arrangement, the cap-like cover 40 may smoothly guide an air flow bumping against the temperature OLP 38 thereby reducing the occurrence of a turbulent flow, and hence, the noise level may be lowered.
Furthermore, if drops of condensation formed on heat exchangers 17a and 17b above the temperature OLP 38 should fall thereupon during a cooling operation, the cap-like cover 40 will protect the temperature OLP 38 from the condensation drops directly falling thereupon. This enhances the detection reliability of the temperature OLP 38. It is also possible to provide the cover 40 atop a fuse 39.

EMBODIMENT 9

Now referring to Fig.9, a ninth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 8 are represented by the same reference characters. Fig.9 illustrates the direction of an air flow in case where a heater 27 and heater support plate 29 are not provided. As indicated by the arrows in the figure, the air flows in substantially vertically downward parallel streams in the proximity of the heater, which tend to slightly converge toward the downstream side. Accordingly, when the heater 27 and heater support plate 29 are to be provided at this place, they should be arranged in a form to conform with the direction of such streams. That is, the heater 27 and the heater support plate 29 should be positioned with a distance therebetween maintained constant or decreased toward the downstream side. Such an arrangement may achieve the minimum air flow resistance to reduce the noise level.

EMBODIMENT 10

Now referring to Figs.10 and 11, a tenth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 9 are represented by the same reference characters. In Figs. 10 and 11, a horizontal plate-like obstacle 41 is provided directly under a heater 27.
With this mode, an air flow AF downstream of the heater 27 (refer to Fig.1 for a downstream-side air flow AF in case where the obstacle 41 is not present) is diffused to be decreased in the density difference from the ambient air flow while expanded in width as it enters a cross-flow fan 18. That is, the downstream-side air flow AF is rendered into the form shown in Fig.10 so as to prevent the occurrence of abnormal sound caused by the downstream-side air flow AF entering the cross-flow fan 18.
Fig.11 is a graphical illustration of the frequency characteristics for showing a state wherein the occurrence of the abnormal sound is reduced by the obstacle 41. As to a level of the abnormal sound produced in the proximity of 500 Hz while the heater is ON, installing the obstacle 41 has improved the frequency characteristics as shown by the broken line in the figure so that the level of the abnormal sound does not differ so much as that when the heater is turned OFF. Although the embodiment utilizes a horizontal plate as the obstacle 41, an equivalent effect may be attained by an obstacle having other sectional forms such as a stick-like form.

EMBODIMENT 11

Now referring to Fig.12, an eleventh embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 10 are represented by the same reference characters. In Fig. 12, a plate-like obstacle 41 is desirably horizontally positioned in order to serve a purpose for diffusing the downstream-side air flow AF for reducing the occurrence of the abnormal sound. Unfortunately, however, a problem exists that the flow resistance increases to reduce the capacity or cause a turbulent air flow, and hence, the level of a turbulent noise other than the abnormal sound increases. In order to avoid this, the obstacle 41 is provided in an inclined position. Such an arrangement may reduce the occurrence of the abnormal sound while preventing the increase in the level of the flow resistance and turbulent noise.

EMBODIMENT 12

Now referring to Fig.13, a twelfth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 11 are represented by the same reference characters. In Fig. 13, a plate-like obstacle 41 is fixed to a heater support plate 29 so as to be disposed directly under a heater 27. Such an arrangement facilitates the mounting of the plate-like obstacle 41.

EMBODIMENT 13

Now referring to Fig.14, a thirteenth embodiment hereof will be described. It is to be noted that the same components as those of Embodiments 1 through 12 are represented by the same reference characters. In Fig. 13, a plate-like obstacle 41 is integrally formed with a heater support plate 29 so as to be disposed directly under a heater 27. Such an arrangement provides an even easier fabrication and mounting operation of the plate-like obstacle 41.

Claims

An indoor unit of an air conditioner comprising:
an air flow passage defined between a front cover and a main body frame and extending toward an outlet port at the lower end thereof, the front cover including inlet ports at the top and front surfaces thereof,

a cross-flow fan disposed within the air flow passage and including an impeller comprised of a plurality of blades arranged in a column-like form,

heat exchangers disposed at places upstream of the cross-flow fan on a front and a rear side, respectively, and

a stabilizer and a rear guider disposed at places on a front side and a rear side, respectively, and defining therebetween a diffuser extending from the cross-flow fan toward the outlet port,

the indoor unit characterized in that both the heat exchangers are independently disposed as spaced from each other by a suitable distance and inclined in a manner to decrease a distance between the uppor portions thereof,

that an elongate plate is provided for bridging a gap between the upper portions of the heat exchangers while the cross-flow fan is located at place in an opening defined between the lower portions of the heat exchangers, and

that a heater is disposed directly under the elongate plate.
An indoor unit of an air conditioner as set forth in Claim 1 characterized in that a heater support plate for supporting the heater is located directly under the elongate plate while substantially trapezoid-shaped side plates are disposed at places on opposite sides with respect to the direction of the rotary axis of the cross-flow fan thereby interconnecting the heat exchangers at the respective side-end portions thereof opposing to each other, whereby the opposite ends of the heater support plate are fixedly retained by the side plates.
An indoor unit of an air conditioner as set forth in Claim 2 characterized in that a first connection wire from one end of the heater extends through an aperture in one of the side plates opposing the one end of the heater whereas a second connection wire from the other end of the heater is reversed along the heater support plate to be extended through the aperture in said side plate along with the first connection wire, the second connection wire having the reversed portion thereof fixedly supported by the heater support plate.
An indoor unit of an air conditioner as set forth in Claim 1 characterized in that a heater support plate for supporting the heater is located directly under the elongate plate while support plates perpendicular to the rear guider are disposed at places on opposite sides with respect to the direction of the rotary axis of the cross-flow fan to thereby fixedly retain the heater support plate at the opposite ends thereof.
An indoor unit of an air conditioner as set forth in Claim 4 characterized in that a first connection wire from one end of the heater extends through an aperture in one of the support plates opposing the one end of the heater whereas a second connection wire from the other end of the heater is reversed along the heater support plate to be extended through the aperture in said support plate along with the first connection wire, the second connection wire having the reversed portion thereof fixedly supported by the heater support plate.
An indoor unit of an air conditioner as set forth in Claim 1 characterized in that an even number of the heaters are disposed in parallel directly under the elongate plate with connection wires extending from the opposite ends of each heater connected in series.
An indoor unit of an air conditioner as set forth in any one of Claims 2 through 5 characterized in that at least one of an abnormality detection means for detecting abnormal states of the heater, such as overcurrent, overheat or the like, and a protection device for interrupting the current is fixed to the heater support plate.
An indoor unit of an air conditioner as set forth in Claim 7 further characterized in that a cap-like cover is provided for covering the top portion of the abnormality detection means and/or protection device.
An indoor unit of an air conditioner as set forth in any one of Claims 2, 3, 4, 5, 7 and 8 characterized in that the heater is mounted to the heater support plate in a manner to maintain a constant distance between the heater and the heater support plate along the direction of air flow or to progressively decrease such a distance toward the downstream side.
An indoor unit of an air conditioner as set forth in any one of Claims 1 through 9 characterized in that an obstacle for stirring an air flow downstream of the heater is disposed directly under the heater.
An indoor unit of an air conditioner as set forth in any one of Claims 1 through 10 characterized in that a plate-like obstacle directly under the heater is inclined relative to the direction of the air flow.
An indoor unit of an air conditioner as set forth in any one of Claims 2, 3, 4, 5, 7, 8, 9, 10 and 11 characterized in that a plate-like obstacle directly under the heater is fixed to the heater support plate.
An indoor unit of an air conditioner as set forth in any one of Claims 2, 3, 4, 5, 7, 8, 9, 10, 11 and 12 characterized in that a plate-like obstacle directly under the heater is integrally formed with the heater support plate.