JPH11166747A - Ceiling embedded air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a blast noise, to prevent short-circuiting, and to reduce costs. SOLUTION: At the inner center of a case body 21 being embedded in a ceiling 22, a shroudless centrifugal fan 23 and an inducer 24 are provided so that the inducer is positioned at a suction upstream side. The inducer 24 is provided with a shroud part 24a where a channel section being gradually expanded as it approaches the centrifugal fan 23, and a bell mouth part 24b that projects by a specific length from a panel 27 while the channel section is gradually expanded so that the upstream side of a suction grill 32 that is the suction port of indoor air is surrounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceiling-mounted air conditioner in which a heat exchanger is arranged around a centrifugal fan.

[0002]

2. Description of the Related Art Conventionally, as this type of air conditioner,
The one shown in FIGS. 3 and 4 is known. In this air conditioner, a heat exchanger 3, a centrifugal fan 4, a motor 5, a drain pan 6, a bell mouth 7, and a suction filter 8 are built in a case body 2 embedded in a ceiling 1, and a grill 9a is provided.
A panel 9 having a louver 9b covers the opening of the case body 2.

[0003] The motor 5 is fixed to a top plate 2a of the case main body 2, and a shaft portion 5a of the motor 5 is fixed to a conical portion 4a of a centrifugal fan 4. During operation of the air conditioner, refrigerant from an indoor unit (not shown) circulates through the heat exchanger 3 and the centrifugal fan 4 is driven by the motor 5.

[0004] By driving the centrifugal fan 4, the indoor 10
Is guided to the bell mouth 7 through the suction grill 9a and the suction port filter 8 of the panel 9, is sucked by the centrifugal fan 4, and is urged by the blade 4b. Then, the air discharged from the centrifugal fan 4 is cooled or heated in the process of passing through the heat exchanger 3, becomes conditioned air A, and is blown out from the outlet 11.

[0005]

In the air conditioner having the above structure, the air flow path is such that the air in the room 10 is sucked in from the bell mouth 7 and finally the conditioned air A is blown out from the outlet 11. Because of the U-turn configuration,
There is a problem that the pressure loss is extremely large and the blowing noise is large.

Although this noise reduction measure is being implemented year by year, further reduction measures are demanded. Further, due to the demand for cost reduction, it has been necessary to reduce the cost of the centrifugal fan 4 from its development to its manufacture.

Further, a grill 9 serving as a suction port for indoor air is provided.
a and the air outlet 11 of the conditioned air A are close to each other, so that a so-called short circuit is apt to occur, in which the airflow at the time of heating is again sucked into the air inlet together with the intake air, and measures are also required. Was.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-ceiling type air conditioner capable of reducing blowing noise, preventing a short circuit, and reducing costs. And

[0009]

The present invention has the following features to attain the object mentioned above. In other words, a shroudless centrifugal fan and an inducer disposed upstream of the shroudless centrifugal fan to form a guide passage for room air to the fan are provided at the center of the case main body buried in the ceiling, and the case main body is provided. A panel that covers the lower opening of the air conditioner, the air inlet for the room air and the air outlet for the conditioned air are formed, and the inducer includes a shroud part whose flow path cross section gradually increases as approaching the fan; A bell mouth portion that protrudes from the panel so as to surround the upstream side of the mouth, and the cross section of the flow path gradually expands in the protruding direction.

[0010] In such a configuration, the bell mouth portion constituting the inducer for guiding the room air to the centrifugal fan is expanded to the upstream side of the suction, and the induce function for guiding the room air to the centrifugal fan is improved. The suction flow is improved. For this reason, the number of rotations of the centrifugal fan required to obtain the same amount of air is reduced, and the blowing noise can be reduced.

Further, since a shroud portion for efficiently guiding the intake air to the centrifugal fan is provided in the inducer, and a shroudless centrifugal fan is used as the centrifugal fan, the manufacturing cost of the centrifugal fan can be reduced. The total cost can be reduced.

Furthermore, since the bell mouth portion surrounds the upstream side of the suction opening formed in the panel, the bell mouth portion serves as a barrier to the flow of the blown air into the suction opening, thereby preventing a short circuit during heating. Can be.
Furthermore, the backflow of the intake air due to the separation in the shroud portion is reduced, and the blowing noise can be further reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an air conditioner according to the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of the air conditioner according to the present embodiment, and FIG. 2 is a plan view of the air conditioner.

In FIG. 1, reference numeral 21 denotes a case main body buried in a ceiling 22.
A centrifugal fan 23 and an inducer 24 located on the suction side (the lower side in the figure) are provided. Centrifugal fan 23
Uses a shroudless centrifugal fan that does not have a shroud on the upstream side of the suction, and has a conical portion 23a having a shaft 2 of a motor 25 fixed to a top plate 22a of the case body 21.
5a.

The discharge side of the centrifugal fan 23 has a heat exchanger 2
6 is disposed so as to surround the centrifugal fan 23, and a drain pan 28 fixed to a panel 27 covering a lower opening of the case body 21 is disposed below the heat exchanger 26. The panel 27 includes a heat exchanger 26 and a room 29.
An air outlet 30 for conditioned air A, which is cooled or heated by passing the intake air from the air, is formed.

The inducer 24 guides the conditioned air A to the centrifugal fan 23. The inducer 24 has a cylindrical shape whose diameter gradually increases from a substantially central portion in the axial direction toward both open ends. A shroud portion 24a that extends while gradually increasing the diameter toward the suction side of 23, and a bell mouth portion 24b that penetrates through the panel 27 and projects a predetermined length into the room 29 while gradually increasing the diameter from the central portion.

That is, the shroud portion 24a on the downstream side of the inducer 24 faces the suction side of the centrifugal fan 23 at a predetermined interval, and the bell mouth portion 24b on the upstream side of the inducer 24 has a panel 27. From the floor 31 side, and is exposed to the room 29, and surrounds the upstream side of a suction grill 32, which is a room air suction port.

Next, the operation of the air conditioner having the above configuration during operation will be described. First, indoor air is drawn into the centrifugal fan 23 by the centrifugal fan 23 driven by the motor 25, passing through the suction grill 32 and the suction port filter 33 while being guided by the inducer 24.

At this time, the bell mouth portion 24b of the inducer 24 is expanded to the suction upstream side of the conventional bell mouth, and the induce function for guiding the room air to the centrifugal fan 23 is improved. The number of rotations of the centrifugal fan 23 necessary for obtaining the blowing amount is reduced, and the blowing sound is reduced.

Then, the intake air sucked into the centrifugal fan 23 is urged by the blades 23b and discharged to the heat exchanger 26. This intake air is cooled or heated in the course of flowing through the heat exchanger 26, and is blown out from the outlet 30 as conditioned air A.

At this time, the upstream side of the suction grille 32, which is a suction port of room air, is surrounded by a bell mouth portion 24b projecting from the panel 27 into the room 29, so that the bell mouth portion 24b prevents the blown air flow from flowing into the suction port. Because of the barrier, it is possible to prevent a short circuit at the time of heating, improve the followability to the set temperature, and improve the air conditioning performance.

Also, the production cost of the centrifugal fan 23 can be reduced by providing the inducer 24 having the shroud portion 24a on the suction upstream side and using a shroudless centrifugal fan instead of the conventional centrifugal fan having a shroud. Thus, the total cost can be reduced. Further, the backflow of the intake air due to the separation at the shroud portion 24a can be reduced, and the blowing noise can be further reduced.

In the air conditioner of this embodiment, the length of the bell mouth 24b projecting from the panel 27 is defined as L, and the outer diameter of the centrifugal fan 23 is defined as D.
It has been confirmed that when the configuration is such that the relationship of D ≧ 0.6 is satisfied, the blowing noise is reduced by about 1.0 dB under a predetermined set air volume.

[0024]

As is clear from the above description, according to the present invention, the following effects can be obtained. (A) Since the bell mouth part constituting the inducer for guiding the room air to the centrifugal fan is extended to the upstream side of the suction so as to protrude a predetermined length from the panel into the room, the inducer for guiding the room air to the centrifugal fan. The function is improved and the suction flow is improved. For this reason, the number of rotations of the centrifugal fan required to obtain the same amount of air can be reduced, and the blowing noise can be reduced.

(B) Since a shroud portion for efficiently guiding the intake air drawn into the case body into the centrifugal fan is provided in the inducer, a shroudless centrifugal fan may be used as the centrifugal fan. Can,
The manufacturing cost of the centrifugal fan can be reduced, and the total cost can be reduced.

(C) Since the upstream side of the suction port is surrounded by a bell mouth portion projecting into the room from the panel, the bell mouth portion serves as a barrier against the inflow of blown air into the suction port,
Short circuit during heating can be prevented, and the ability to follow a set temperature can be improved to improve air conditioning performance.

(D) Further, the backflow of the intake air due to the separation at the shroud portion can be reduced, and the blowing noise can be further reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an embedded ceiling air conditioner according to the present invention.

FIG. 2 is a plan view of the ceiling-mounted air conditioner shown in FIG.

FIG. 3 is a longitudinal sectional view showing an example of a conventional ceiling-mounted air conditioner.

FIG. 4 is a plan view of the ceiling-mounted air conditioner shown in FIG.

[Explanation of symbols]

 Reference Signs List 21 case body 22 ceiling 23 (shroudless) centrifugal fan 24 inducer 24a shroud part 24b bellmouth part 27 panel 30 outlet 32 suction grill (suction port) A conditioned air

Claims (1)

[Claims] A shroudless centrifugal fan, and an inducer located upstream of the shroudless centrifugal fan to form a guide flow path for room air to the fan in a case body embedded in a ceiling; A panel that covers the lower opening of the case main body is formed with a suction port for the room air and a blowout port for the conditioned air, and the inducer includes a shroud portion whose flow path cross section gradually increases as approaching the fan. A ceiling-embedded air conditioner, comprising: a bell mouth portion that protrudes from the panel so as to surround the upstream side of the suction port, and that has a channel cross section that gradually increases in the protruding direction.