JPH06323564A - Air conditioner - Google Patents

Abstract

PURPOSE:To obtain a noise reduction construction which exhibits a sufficient noise reducing performance in a casing of an air conditioner without enlarging the size of the air conditioner. CONSTITUTION:In an air-handing unit 1, a duct silencer 8 made of a sound absorptive material is installed in a sound reducing chamber 2g where air is sent by an air fan 6 and a sound absorptive material 9b is attached on the surface of the inner wall of the sound reducing chamber 2g. The duct silencer 8 is equipped with an active sound attenuator 10 and a sloped wall 8a is provided at a part of the sound attenuation duct 8 on the upstream side of air flow so that its diameter is gradually enlarged toward the downstream side. Thereby, noise is reduced by means of the chamber effect in the peripheral space of line duct silencer 8 and detection of noise by a noise detecting microphone 10a is accurately performed by the flow straightening effect on the upstream side of the noise detecting microphone 10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner,
In particular, the present invention relates to an improvement in a structure for reducing a blowing sound level that becomes noise in the vicinity of an outlet of a blowing fan.

[0002]

2. Description of the Related Art Conventionally, an air conditioner generally called an air handling unit has an air filter, a hot water coil, a cold water coil, and a blower fan in an air conditioner casing having an outside air intake port and an air conditioning air supply port. It is equipped with a fan, etc., which takes in outside air from the outside air intake, purifies it by removing dust with an air filter, and then adjusts the temperature with a hot water coil or a cold water coil to produce conditioned air. Is blown toward the room from the air conditioning air supply port by a blower fan. Further, a duct is connected to the conditioned air supply port of this casing, and in the case where the air blown from this conditioned air supply port is supplied to a plurality of rooms, the middle of the duct is branched so that each of It is designed to be extended toward the room.

[0003]

By the way, in this type of air conditioner, there is a risk that the blowing noise from the blowing fan will become noise and be propagated to each room through the duct. Various means have been proposed so far for reducing noise. As an example thereof, a sound absorbing material is attached to the inner wall of the duct to reduce the noise level, and a so-called active silencer disclosed in JP-A-62-1156 is used in the duct. And the like, the noise level is reduced by adding a sound of the same amplitude in antiphase to the noise in the duct.

However, in such a structure in which the muffling structure is arranged in the duct, the duct is branched as described above, especially in the immediately downstream of the conditioned air supply port of the air conditioner casing. For ducts that have a branch, it is necessary to adopt a sound deadening structure for each of the branched ducts, which complicates the structure of the entire air conditioning system, complicates the installation work, and raises costs. Will be invited. Therefore, it is required to reduce the noise level inside the air conditioner casing, that is, near the air outlet of the blower fan, but the duct length inside the air conditioner casing is small (for example, the height of the air conditioner casing). However, it is not possible to sufficiently muffle sound by simply adopting the conventional sound deadening structure for the duct inside the air conditioner casing as it is, because such a conventional structure provides sufficient sound muffling. In this case, the distance from the outlet of the blower fan to the conditioned air supply port of the air conditioner casing must be set large, which leads to an increase in the size of the entire device.

The present invention has been made in view of this point, and it is an object of the present invention to provide a sound deadening structure capable of exhibiting sufficient sound deadening performance in an air conditioner casing without increasing the size of the device. To aim.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 arranges a duct for supplying conditioned air in an air conditioner casing, and surrounds the outer periphery of the duct. The space is designed to function as a muffling chamber. Specifically, as shown in FIG. 1, an air conditioning air supply port for blowing out the air conditioning air to the outside of the air conditioner casing (2) in the downstream end chamber (2g) formed in the air conditioner casing (2). (2b) is formed, and the air blown from the outlet (6c) of the blower fan (6) is introduced into this downstream end chamber (2g). After going through (2g),
It is premised on an air conditioner adapted to be supplied indoors from the conditioned air supply port (2b). An air conditioning air supply duct (8) is provided in the downstream end chamber (2g) between the air outlet (6c) of the blower fan (6) and the air conditioning air supply port (2b). At least a part of the air supply duct (8) is formed by the sound absorbing material (9a). Further, the sound absorbing material (9b) is arranged in the space around the outside of the air-conditioning air supply duct (8) in the downstream end chamber (2g).

According to a second aspect of the present invention, in an air conditioner equipped with a so-called active muffler, the duct shape is such that the muffling performance of the muffler is improved. Specifically, a detection microphone (10a), a speaker (10c), and a monitor microphone (10b) are arranged in this order from the air circulation upstream side in the air-conditioning air supply duct (8) and detected by the detection microphone (10a). Noise from the speaker (10c) with the opposite phase and the same amplitude
(8) Radiates into the monitor microphone (10b)
It is premised on an air conditioner equipped with a silencer (10) that corrects the additional sound so that the reduced sound level on the downstream side of the speaker (10c) detected by the speaker is reduced. And, at least a part of the conditioned air supply duct (8) is formed by an inclined duct part (8a) in which the flow area of the conditioned air gradually increases toward the downstream side of the conditioned air flow, and the inclined duct part is formed. The configuration is such that the position of the air circulation upstream end of (8a) is set on the air circulation upstream side of the position where the detection microphone (10a) is arranged.

According to a third aspect of the present invention, in the air conditioner according to the second aspect, the air of the inclined duct portion (8a) in the outer periphery of the inclined duct portion (8a) of the air-conditioning air supply duct (8). The iron plate (11) is arranged between the position of the upstream end of the distribution and the position where the detection microphone (10a) is arranged.

[0009]

With the above construction, the present invention provides the following actions. In the invention according to claim 1, the air blown from the air outlet (6c) of the air blower fan (6) is the downstream end chamber.
After flowing through the air-conditioning air supply duct (8) arranged in (2g), the air is supplied from the air-conditioning air supply port (2b) of the air conditioner casing (2) toward the room. When the airflow thus flows through the air-conditioning air supply duct (8), in addition to the sound deadening effect of the sound deadening duct (8) formed at least partly by the sound absorbing material (9a), the sound deadening duct (8) The space around the outside of () functions as a muffling chamber, and the sound absorbing material (9b) arranged in this space allows the air conditioner casing to
(2) The noise level inside will be significantly reduced.

According to the second aspect of the present invention, at the time of the silencing operation by the silencing device (10), at least a part of the conditioned air supply duct (8) is directed toward the downstream side of the conditioned air distribution area to distribute the conditioned air distribution area. Is formed by the gradually increasing inclined duct section (8a), the conditioned air is rectified immediately downstream of the blower fan outlet, and turbulent flow to the detection microphone (10a) is generated. The adverse effect is suppressed, and the noise in the duct (7) is properly detected by the detection microphone (10a), so that the additional sound emitted from the speaker (10c) can be appropriately set. .

According to the third aspect of the invention, since the iron plate (11) is arranged around the outer periphery of the inclined duct portion (8a) of the air-conditioning air supply duct (8), the detection microphone (10a) and Correlation with the monitor microphone (10b), so-called coherence, becomes high, and the silencing performance is improved.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a view showing the internal structure of an air handling unit (1) according to this example. The air handling unit (1) includes an air filter (3), a hot water coil (4) and a cold water coil (5) in a casing (2) having an outside air intake port (2a) and an air conditioning air supply port (2b). ), A blower fan (6), etc. are provided. In addition, this air handling unit (1) is installed in the conditioned air supply port (2b).
A duct (7) extending outwardly from (2b) is connected, and this duct (7) is branched into multiple parts immediately downstream of the conditioned air supply port (2b) (the branching state is not shown). The conditioned air blown from the conditioned air supply port (2b) is supplied to a plurality of rooms (not shown).

Hereinafter, this air handling unit (1)
The configuration of will be described in detail. The casing (2) is divided into left and right two chambers (2c) and (2d) in FIG. 1, and the upstream chamber (2c) facing the outside air intake (2a) is
The air filter (3) including a pre-filter (3a) and a main filter (3b), a cold water coil (5), and a hot water coil (4) are arranged in order from the right side in FIG. 1, and the outside air intake port (2a) is arranged. The outside air taken into the upstream chamber (2c) from the above is purified by the air filter (3) with dust removed, and then the temperature is adjusted by passing through the hot water coil (4) and the cold water coil (5). It becomes conditioned air and is introduced into the downstream chamber (2d) facing the conditioned air supply port (2b). Further, the upstream side chamber (2c) and the downstream side chamber (2d) are communicated with each other at their lower end portions. The hot water coil (4) and the cold water coil (5) are designed so that hot water or cold water flows only on one side.Hot water is supplied to the hot water coil (4) during heating operation and cold water coil (5) is supplied during cooling operation.
Cold water is caused to flow into each of them, and each water exchanges heat with the outside air taken in through the outside air intake port (2a), so that the outside air becomes conditioned air. On the other hand, the downstream chamber (2d)
Is partitioned by a partition plate (2e) extending in the horizontal direction into a lower fan chamber (2f) and an upper silencing chamber (2g) as a downstream end chamber. A blower fan (6) is arranged in the blower fan chamber (2f), and a fan driving motor (6a) is connected to the blower fan (6) via a fan belt (6b). Has been done. Then, as the blower fan (6) is driven by the rotation of the motor (6a), the conditioned air generated in the upstream chamber (2c) is blown from the blower fan chamber (2f) to the muffling chamber (2g). It has become.

The characteristic structure of this embodiment is the internal structure of the silencing chamber (2g). The internal structure of the muffling room (2g) will be described below. This muffler chamber (2g) is provided with a muffler duct (8) as an air conditioning air supply duct that connects the air outlet (6c) of the blower fan (6) and the air conditioning air supply port (2b). It is configured. A sound absorbing material (9b) is attached to the entire inner wall surface of the sound deadening chamber (2g), and the sound deadening duct (8) is also formed of the sound absorbing material (9a). Explaining in detail the structure of this muffler duct (8), the blower fan
A plurality of frame members (not shown) as a duct frame are laid from the air outlet (6c) of (6) to the conditioned air supply port (2b), and the sound absorbing material (9a) is arranged across each frame member. As a result, a passage formed by the sound absorbing material (9a) is formed from the air outlet (6c) of the blower fan (6) to the conditioned air supply port (2b). In other words, the sound deadening chamber (2g) is a double sound deadening space in which a space formed by the sound absorbing material (9b) is further formed around the air circulation space formed by the sound absorbing material (9a). It has a structure, and the space formed around the outer periphery of the sound deadening duct (8) functions as a sound deadening chamber. Further, as a feature of the structure of the sound deadening duct (8) according to the invention of claim 2, the sound deadening duct (8) is
Except for the vicinity of the conditioned air supply port (2b), one side surface is inclined so that the flow passage area gradually increases from the air outlet (6c) of the blower fan (6) toward the downstream side of the air flow. It is formed of an inclined wall (8a) as an inclined duct portion. That is, by gradually increasing the passage area of the conditioned air blown from the blower fan (6), the rectifying action of the conditioned air is exerted. And
An active muffling device (10) is provided in the muffler duct (8). In FIG. 1, (10a) is a detection microphone, (10b) is a monitor microphone, and (10c) is a speaker. Generates an additional sound signal having the same amplitude as the noise signal based on the noise detected by the detection microphone (10a) but in the opposite phase, and the additional sound based on this additional sound signal is output to the speaker.
The noise is radiated from (10c) to the space inside the duct (8). Further, the reduced sound level on the downstream side of the speaker (10c) is monitored by a monitor microphone (10b), and the additional sound signal is feedback-corrected so that the reduced sound level at this monitor microphone (10b) becomes zero. It is like this. Thus, in the configuration of this example, the blower outlet (6c) of the blower fan (6) where turbulence is particularly likely to occur
Although the detection microphone (10a) is arranged in the vicinity, as described above, it is configured so that the passage area of the conditioned air blown from the blower fan (6) gradually increases, and Since the rectification is performed, the adverse effect of the turbulence on the detection microphone (10a) is suppressed, and the detection microphone (10a) has a duct.
(7) The noise inside is properly detected.

Next, the operation of the air handling unit (1) constructed as described above will be described. Motor (6a)
The blower fan (6) is driven by the rotation of the
After the outside air is introduced into the upstream chamber (2c) from the outside air intake (2a) of (2) and the outside air is purified by the air filter (3) with dust removed, a hot water coil (4) or a cold water coil
The temperature is adjusted by (5) to become conditioned air, and this conditioned air is introduced into the blower fan chamber (2f) of the downstream side chamber (2d).
The conditioned air is blown into the muffle room by the blower fan (6).
It is supplied to the muffler duct (8) in (2g), and then is led to the indoor air duct (7) from the air conditioning air supply port (2b) through the muffler duct (8), and the air conditioning in each room is controlled. Done.
In such an operation, the noise level in the muffling duct (8) is reduced by the sound absorbing materials (9a), (9b) and the active muffling device (10), and the level of noise propagated in the room is greatly increased. Will be reduced to. Explaining the silencing operation by each configuration, the silencing duct (8) is the sound absorbing material (9a).
The sound absorbing material (9b) is attached to the inner wall of the sound deadening chamber (2g) that forms the space around the sound deadening duct (8), and this space functions as a sound deadening chamber. As a result, the noise level in the muffler duct (8) is significantly reduced. Meanwhile, active silencer
In (10), the passage area of the conditioned air blown from the blower fan (6) is gradually increased as described above, and it is arranged directly at the outlet (6c) of the blower fan (6). Since the conditioned air is rectified downstream, the adverse effect of turbulence on the detection microphone (10a) is suppressed, and the noise in the duct (7) is properly detected by the detection microphone (10a). This makes it possible to properly set the additional sound emitted from the speaker (10c), which also significantly reduces the noise level in the muffler duct (8). . As described above, according to the configuration of this example, it is possible to significantly reduce the noise level inside the casing (2) of the air handling unit (1).
Since it is not necessary to adopt a structure for noise reduction in the duct (7) extending from (1) toward the room, as in this example,
For ducts (7) that are branched immediately downstream of the conditioned air supply port (2b), there is no need to adopt a structure for silencing each of the branched ducts. It is possible to reliably suppress the propagation of noise into the room without complicating the structure of the entire air conditioning system, complicating the installation work, and increasing the cost.

Next, the results of experiments and analyzes conducted to confirm the above effects will be described. First, an analysis for confirming the effect of the shape of the sound deadening duct (8) for appropriately performing active sound deadening in the casing (2) will be described. First, the detection microphone (10a) and the monitor microphone are required for proper active muffling.
It is necessary that the correlation between (10b) and so-called coherence is high. Therefore, we analyze the relationship between this coherence and turbulence. Fig. 2 shows the relationship between frequency and coherence when the same air volume is passed through two types of ducts with different diameters. Fig. 2 (a) shows a duct with a small diameter (260mm). 2 (b) shows the case where the duct diameter is large (380 mm). Also,
The air volume of each was 60 m ³ / min. As can be seen from this figure, the higher coherence is ensured for the one having the larger duct diameter, that is, the one having the smaller wind speed and less likely to generate the turbulence (see FIG. 2B). In other words, if the duct diameter is small, a microphone that detects vortex noise due to turbulence, etc.
It is considered that the coherence decreases due to the presence of uncorrelated noise in the detection signal of (10a) and the detection signal of the monitor microphone (10b). From this, it can be seen that lowering the wind speed in the duct to suppress the generation of turbulence leads to an improvement in the silencing performance of the active silencing device. Based on this, the coherence between the case where the entire duct is simply increased in diameter as shown in FIG. 3 and the case where the duct (8) is gradually increased in diameter as in the above-described embodiment shown in FIG. Analysis was performed and the results are shown in FIG. Incidentally, FIG.
(a) shows the case where the diameter of the duct (8) is gradually increased as shown in FIG. 4, and FIG. 5 (b) shows the case where the entire duct is simply made large as shown in FIG. In this way, the duct (8) having a gradually increasing diameter can maintain higher coherence. The reason why the coherence becomes low when the entire duct has a large diameter is that rapid diffusion occurs at the outlet (6c) of the blower fan (6), which disturbs the air flow although the wind speed decreases. It is possible that As a result, the active silencer (10) is provided directly downstream of the blower fan (6) by adopting a duct structure in which not only the wind speed is lowered but also the duct diameter is gradually increased as in the above-described embodiment. It has been confirmed that the muffling effect is effectively exerted in the case of being installed in.

Next, the analysis performed for confirming the sound deadening effect by the above-mentioned sound absorbing materials (9a), (9b) will be described. In order to confirm this effect, an experiment was conducted on three types of configurations as shown in FIGS. First, the one shown in FIG. 6 does not have a muffling duct, that is, a blower fan (6).
Is configured so that air is blown out into the entire silencing chamber (2g) and the passage of the air is suddenly expanded. The structure shown in FIG. 7 is the same as that described above without the active silencing device. The structure shown in FIG. 8 is provided with a sound deadening duct (8) as shown in the example. Further, the sound deadening duct (8) is provided with an active sound deadening device (10), and the structure of the embodiment described above is further added. In addition to the structure, as the structure according to the invention of claim 3, the outer side of the sound deadening duct (8) between the lower end of the sound deadening duct (8) and the periphery of the position where the detection microphone (10a) is arranged is an iron plate (1).
It is configured to be covered by 1). And
FIG. 9 (a) shows an iron plate (11) in the structure shown in FIG.
The relationship between frequency and coherence when
FIG. 9B shows the relationship between frequency and coherence in the configuration shown in FIG. in this way,
Even if the iron plate (11) is removed, a relatively large coherence is secured, but if the iron plate (11) is arranged, it can be seen that the coherence can be secured even higher in a wide band. . Further, FIG. 10 shows the relationship between the frequency and the sound pressure level on the duct outlet side in each of the above-mentioned three types (shown in FIGS. 6 to 8). The sound pressure level was measured by the “quasi-free sound field method” of HASS-110 in the Society of Air Conditioning and Sanitation Engineering standards. Specifically, as shown in FIG. 11, a 6 m duct (7) is connected to the conditioned air supply port (2b) of the casing (2), and this duct is
Multiple sound pressure observation points (P1) to the same distance from the downstream end of (7)
(P6) was set and the sound pressure was observed in each. The sound pressure observation points (P1) to (P6) are located at the duct (7).
The straight line (s) connecting the center (O) of the downstream end of the station and the observation points (P1) to (P6)
The angle θ between 1) and the axis (s2) of the duct (7) is 30 each.
It is set to °, 60 °, 80 °, 100 °, 120 °, 150 °. Then, in this case, the effective radiation power level as the sound pressure is calculated by the following formula.

[Equation 1] Lw: effective radiant power level, Lpm: average octave band sound pressure level, Lpi: sound pressure level at the i-th measurement point, and the white one on the left side of the graph in FIG. Having the structure shown in 6,
The diagonally lower right hatching at the center has the structure shown in FIG. 7, and the diagonally lower left hatching at the rightmost has the structure shown in FIG.
As described above, the structure shown in FIG. 7 has excellent silencing characteristics in the entire band, whereas the structure shown in FIG. 8 has particularly excellent silencing characteristics in the low frequency range. I understand. It should be noted that L in FIG. 10 indicates that the sound pressure level in each frequency band is linearly added, and A is corrected by A (the addition ratio in each frequency band is corrected according to human hearing). Is shown.

Further, FIG. 12 shows the relationship between the frequency and the sound pressure level at the casing outlet side with and without active muffling in the configuration shown in FIG. In the graph of FIG. 12, the white one on the leftmost side is the conventional standard machine, and the one on the right diagonally lower hatched in the center is the case where active muffling is not performed. The diagonally lower left hatching located on the right side is when active muffling is performed. As can be seen from this figure, when active muffling is performed, a high muffling effect is obtained particularly in the 125 Hz and 250 Hz bands.

As described above, in the configuration of this example, the muffling duct
Improvement of active noise reduction performance due to improvement of shape of (8),
A sound deadening duct (2g) made up of double sound deadening space structure
Combined with the structure that makes the space formed around the outside of (8) function as a sound deadening chamber, the casing
(2) It will be possible to exhibit high noise reduction performance inside.

In the embodiment described above, the muffler duct (8)
Although the shape is formed by the inclined wall (8a) with one side inclined, the present invention is not limited to this, and as shown in FIG. (FIG. 13 (a) shows a three-sided slope, and FIG. 13 (b) shows a four-sided slope), or as shown in FIG. 14, the duct side faces are curved and flow toward the downstream side of the air flow. The road area may be gradually increased.

[0021]

As described above, according to the present invention, the following effects are exhibited. According to the invention of claim 1, in the downstream end chamber (2g), the conditioned air supply duct (8) is provided across the air outlet (6c) of the blower fan (6) and the conditioned air supply port (2b). And at least a part of the air-conditioning air supply duct (8) is formed by a sound absorbing material (9a), and the space around the outside of the air-conditioning air supply duct (8) in the downstream end chamber (2g). Since the sound absorbing material (9b) is arranged in the space, in addition to the sound deadening effect by the sound deadening duct (8), the space around the sound deadening duct (8) functions as a sound deadening chamber and this space The noise level inside the air conditioner casing (2) is greatly reduced by the action of the sound absorbing material (9b) installed in the air conditioner casing (2) without increasing the size of the device. It is possible to exert a sufficient silencing performance in ().

According to the second aspect of the present invention, with respect to the air-conditioning air supply duct (8) in which the active silencer is arranged,
At least a part of the conditioned air supply duct (8) is formed by an inclined duct part (8a) in which the flow area of the conditioned air gradually increases toward the downstream side of the conditioned air flow, and the inclined duct part (8a ) Of the air flow upstream end of the microphone (1
Since the air-conditioning air is rectified in the upstream side of the detection microphone (10a) because the air flow is set to the upstream side of the arrangement position of (0a), the detection microphone is rectified.
Since the adverse effect of turbulence on (10a) is suppressed and the noise in the duct (7) is properly detected by the detection microphone (10a), this active silencer is installed in the air conditioner casing. Even if the air conditioner is installed, the noise level in the air conditioner casing will be significantly reduced, and sufficient muffling performance will be achieved in the air conditioner casing without increasing the size of the device. Can be made.

According to the third aspect of the present invention, the detection microphone (from the position of the air circulation upstream end of the inclined duct portion (8a) in the outer periphery of the inclined duct portion (8a) of the air conditioning air supply duct (8) is detected. Since the iron plate (11) is arranged up to the arrangement position of (10a), the correlation between the detection microphone (10a) and the monitor microphone (10b), so-called coherence, becomes high, and the silencing performance is improved. It is possible to improve.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal structure of an air handling unit.

FIG. 2 is a diagram showing a relationship between respective frequencies and coherences when the same air volume is circulated in two types of ducts having different diameters.

FIG. 3 is a diagram showing a structure of a duct having a large diameter as a whole.

FIG. 4 is a diagram showing a structure of a duct whose diameter is gradually increased.

FIG. 5 is a diagram showing a relationship between frequency and coherence according to a duct shape.

FIG. 6 is a schematic diagram of an air conditioner that does not include a muffling duct.

FIG. 7 is a schematic diagram of an air conditioner including a muffling duct.

[Fig. 8] A sound deadening duct is provided with an active sound deadening device,
Further, it is a schematic view of an air conditioner in which an iron plate is arranged outside the muffling duct.

FIG. 9 is a diagram showing a relationship between frequency and coherence depending on the presence or absence of an iron plate.

FIG. 10 is a diagram showing the relationship between the frequency and the sound pressure level on the duct outlet side in each of the air conditioners of FIGS. 6 to 8;

FIG. 11 is a diagram showing how the sound pressure level at the outlet of the duct is measured.

FIG. 12 is a diagram showing the relationship between the frequency and the sound pressure level on the casing outlet side with and without active silencing in the configuration shown in FIG. 8;

FIG. 13 is a diagram showing a modification of the shape of the muffling duct.

FIG. 14 is a diagram showing another modification of the sound deadening duct shape.

[Explanation of symbols] (1) Air handling unit (air conditioner) (2) Casing (2b) Air-conditioning air supply port (2g) Muffler chamber (downstream end chamber) (6) Blower fan (6c) Air outlet (8) Noise reduction duct (air conditioning air supply duct) (8a) Inclined wall (inclined duct part) (9a), (9b) Sound absorbing material (10) Active noise reduction device (10a) Detection microphone (10b) Monitor microphone (10c) Speaker (11) ) Iron plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Ito 1304 Kanaoka-cho, Sakai City, Osaka Prefecture Daikin Industries, Ltd. Kanaoka Plant, Sakai Manufacturing Co., Ltd. Kishiwada Factory Co., Ltd.

Claims (3)

[Claims] 1. A conditioned air supply port (2b) for blowing conditioned air outside the air conditioner casing (2) is formed in a downstream end chamber (2g) formed in the air conditioner casing (2). The air blown out from the air outlet (6c) of the blower fan (6) is introduced into this downstream end chamber (2g), and after this airflow passes through the downstream end chamber (2g), In the air conditioner adapted to be supplied from the conditioned air supply port (2b) toward the room, the outlet of the blower fan (6) is provided in the downstream end chamber (2g).
An air-conditioning air supply duct (8) is provided between (6c) and the air-conditioning air supply port (2b).
(8) is at least partially formed by the sound absorbing material (9a), and the sound absorbing material (9b) is provided in the space around the air-conditioning air supply duct (8) in the downstream end chamber (2g). An air conditioner characterized by being provided. 2. A detection microphone (10a) and a speaker (10) are arranged in the air-conditioning air supply duct (8) in order from the air flow upstream side.
c), the monitor microphone (10b) is arranged, and an additional sound of the same amplitude with the opposite phase to the noise detected by the detection microphone (10a) is introduced from the speaker (10c) into the air-conditioning air supply duct (8). In an air conditioner equipped with a muffler (10) that radiates and corrects the additional sound so that the reduced sound level on the downstream side of the speaker (10c) detected by the monitor microphone (10b) becomes small. At least a part of the conditioned air supply duct (8) is formed by an inclined duct part (8a) in which the circulated area of the conditioned air gradually increases toward the downstream side of the conditioned air distribution. An air conditioner characterized in that a position of an air circulation upstream end of the duct part (8a) is set on an air circulation upstream side with respect to a position where the detection microphone (10a) is arranged. 3. An inclined duct part of an air-conditioning air supply duct (8)
An iron plate (11) is arranged between the position of the air circulation upstream end of the inclined duct part (8a) on the outer periphery of (8a) and the position where the detection microphone (10a) is arranged. The air conditioner according to claim 2.