EP3748238A1 - Ceiling-embedded air conditioner - Google Patents
Ceiling-embedded air conditioner Download PDFInfo
- Publication number
- EP3748238A1 EP3748238A1 EP18904199.9A EP18904199A EP3748238A1 EP 3748238 A1 EP3748238 A1 EP 3748238A1 EP 18904199 A EP18904199 A EP 18904199A EP 3748238 A1 EP3748238 A1 EP 3748238A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- shroud
- heat exchanger
- gap
- end portion
- blower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/24—Means for preventing or suppressing noise
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/0007—Indoor units, e.g. fan coil units
- F24F1/0018—Indoor units, e.g. fan coil units characterised by fans
- F24F1/0022—Centrifugal or radial fans
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/0007—Indoor units, e.g. fan coil units
- F24F1/0043—Indoor units, e.g. fan coil units characterised by mounting arrangements
- F24F1/0047—Indoor units, e.g. fan coil units characterised by mounting arrangements mounted in the ceiling or at the ceiling
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/22—Means for preventing condensation or evacuating condensate
Definitions
- the present invention relates to a ceiling-cassette air conditioner.
- An indoor unit of a ceiling-cassette air conditioner is internally provided with a centrifugal blower, and a lower surface of the indoor unit has a bell mouth having an opening. A diameter of the opening decreases upward and inward from a suction port.
- a drain pan for receiving water condensed and dropped on a surface of a heat exchanger during a cooling operation is installed inside the indoor unit.
- the centrifugal blower has an impeller connected to a rotary shaft.
- the impeller includes a hub (main plate) installed on an upper portion of the impeller and connected to the rotary shaft, a plurality of blades in which one end side is connected to the hub and the other end side is connected to a shroud, and the shroud that connects the other ends of the blades to each other and whose diameter increases upward and outward from the bell mouth side.
- PTL 1 below discloses that the shroud is installed to be relatively rotatable inside a suction-side end portion of the shroud to maintain a predetermined gap (L1) between the shroud and the bell mouth.
- An upper end portion of a bell mouth is accommodated inside a suction-side end portion of a shroud, and a gap is disposed between the shroud and the bell mouth.
- a drain pan has two side walls (wall portions) to face each of an inside and an outside of a heat exchanger in order to form a drain groove for receiving drain water.
- a discharge-side end portion of the shroud is located above an inner peripheral wall portion installed inside the heat exchanger in the drain groove, and a gap is disposed between the drain groove and the shroud.
- a suction side of the shroud has a gap from the bell mouth, and a discharge side of the shroud has a gap from the inner peripheral wall portion of the drain groove.
- the inventor has found a fact as follows. If air suctioned by a blower bypasses the blade side without passing through a blade side with respect to the shroud, and passes through the gap between the bell mouth and the shroud, the air causes noise. In addition, the inventor has found another fact as follows. In a case where the air discharged from the blower enters the gap between the shroud and the inner peripheral wall portion of the drain groove, and the air is stagnant or an airflow is separated on a lower side of the shroud, the air also causes the noise.
- the present invention is made in view of the above-described circumstances, and an object thereof is to provide a ceiling-cassette air conditioner capable of reducing noise generated by air suctioned or air discharged by a blower.
- a ceiling-cassette air conditioner including a heat exchanger, a blower having a tubular shroud having a diameter which increases upward and outward, and installed inside the heat exchanger, a bell mouth installed below the shroud and on a suction side of the blower, and a drain pan having a concave drain groove which accommodates a lower portion of the heat exchanger.
- a ratio of a second gap B between a discharge-side end portion of the shroud and a side wall of the drain groove inside the heat exchanger with respect to a first gap A between an upper end portion of the bell mouth and a suction-side end portion of the shroud is B/A ⁇ 3 or 10 ⁇ B/A.
- a height of the side wall of the drain groove inside the heat exchanger may be higher than a side wall of the drain groove outside the heat exchanger.
- the ceiling-cassette air conditioner (hereinafter, referred to as an "air conditioner”) includes an indoor unit 1, an outdoor unit (not illustrated), and a refrigerant pipe (not illustrated) that connects the indoor unit 1 and the outdoor unit to each other.
- the indoor unit 1 is installed so that a case body 2 is cassette in a ceiling. As illustrated in Fig. 2 , the case body 2 is internally equipped with a heat exchanger 7, a drain pan 10, a motor 5, a blower 6, and a bell mouth 12. A ceiling panel 8 exposed on a ceiling surface is mounted on a lower portion of the case body 2.
- Fig. 1 is a bottom view when the indoor unit 1 is viewed from an indoor side, that is, when the indoor unit 1 is viewed from a lower surface of the indoor unit 1.
- Fig. 2 is a longitudinal sectional view taken along line II-II in Fig. 1 .
- the blower 6 is a centrifugal blower, and has an impeller 22 connected to a rotary shaft 21.
- the impeller 22 includes a hub (main plate) 23 installed in an upper portion of the impeller 22 and connected to the rotary shaft 21, a plurality of blades 24 in which one end side is connected to the hub 23 and the other end side is connected to a shroud 25, and the shroud 25 that connects the other ends of the blades 24 to each other and whose diameter increases upward and outward from the bell mouth 12 side.
- the shroud 25 has a tubular shape.
- a radius of a lower portion is larger than a radius of an upper portion, and the radius gradually increases from the lower portion to the upper portion.
- a suction-side end portion of the shroud 25, that is, a lower end portion is located on an outer peripheral side of the bell mouth 12, and has a gap from the bell mouth 12.
- a discharge-side end portion of the shroud 25, that is, an upper end portion is located above an inner peripheral wall portion 18a of a drain groove 18, and has a gap from the inner peripheral wall portion 18a.
- the bell mouth 12 is a tubular member, and is installed below the shroud 25 and on a suction side of the blower 6.
- a radius of a lower portion is smaller than a radius of an upper portion, and the radius gradually decreases from the lower portion to the upper portion.
- An upper end portion of the bell mouth 12 is accommodated inside the suction-side end portion of the shroud 25.
- the drain pan 10 is disposed in a lower portion of the heat exchanger 7, and receives drain water dropped from the heat exchanger 7.
- the bell mouth 12 is disposed in a lower portion of the drain pan 10.
- a suction port 3 is formed in a central portion on a lower surface of the indoor unit 1, and a discharge port 4 is formed adjacent to the suction port 3 and along an outer peripheral portion on the lower surface of the indoor unit 1.
- a suction grill 11 and a filter 13 disposed above the suction grill 11 are installed in the suction port 3.
- the drain pan 10 is made of styrene foam, and a surface for storing the drain water is coated with a waterproof paint.
- a shape of the drain pan 10 in a plan view is a substantially quadrangular shape. Openings 16 and 17 are formed in the drain pan 10 to correspond to the suction port 3 and the discharge port 4.
- a bottom portion 10a of the drain pan 10 is disposed over an entire region having the heat exchanger 7 installed therein, along a lower portion of the heat exchanger 7 disposed to surround the blower 6.
- Fig. 3 is a plan view illustrating the drain pan 10.
- a concave drain groove 18 is formed in the drain pan 10, and the drain water is accumulated inside the drain groove 18.
- the drain groove 18 has an inner peripheral wall portion 18a formed inside the heat exchanger 7, that is, on an inlet side of the heat exchanger 7, and an outer peripheral wall portion 18b formed outside the heat exchanger 7, that is, on an outlet side of the heat exchanger 7.
- the inner peripheral wall portion 18a is disposed along the opening 16 formed corresponding to the suction port 3.
- the outer peripheral wall portion 18b is disposed along the opening 17 formed corresponding to the discharge port 4.
- the lower portion of the heat exchanger 7 is accommodated in the drain groove 18, and a height position of a lower end of the heat exchanger 7 is lower than an upper end of the drain groove 18.
- the outer peripheral wall portion 18b of the drain groove 18 prevents the drain water adhering to the lower portion of the heat exchanger 7 from being scattered outward.
- a convex portion 19 protruding upward is formed in the bottom portion 10a of the drain pan 10.
- the heat exchanger 7 is placed on an upper surface of the convex portion 19.
- the convex portion 19 is formed corresponding to a shape of a bottom surface of the heat exchanger 7 along the bottom surface of the heat exchanger 7 so that a gap from the heat exchanger 7 is not formed as far as possible.
- the bottom portion 10a of the above-described drain pan 10 is formed at a lower position than the bottom portion 10a inside the heat exchanger 7. In this manner, the water accumulated in the drain pan 10 is easily guided outward from the inside of the heat exchanger 7.
- the blower 6 is disposed inside the heat exchanger 7. A wind flow from the blower 6 is oriented outward from the inside of the heat exchanger 7. Accordingly, the drain water accumulated in the drain pan 10 is easily discharged outward from the inside of the heat exchanger 7 by using a wind force.
- an insulation 20 is installed between a lower portion of the heat exchanger 7 and an upper surface of the convex portion 19. In this manner, a space between the heat exchanger 7 and the convex portion 19 is closed by the insulation 20. Accordingly, it is possible to reduce the air flowing outward from the inside of the heat exchanger 7 after passing through a gap without passing through the heat exchanger 7.
- the insulation 20 is installed between the lower portion of the heat exchanger 7 and the upper surface of the convex portion 19, the insulation 20 is accommodated in the drain groove 18. Therefore, even the drain water dropped from the heat exchanger 7 and adhering to the insulation 20 is prevented from being scattered outward.
- a ratio of the second gap B between the discharge-side end portion of the shroud 25 and the inner peripheral wall portion 18a of the drain groove 18 with respect to the first gap A between the upper end portion of the bell mouth 12 and the suction-side end portion of the shroud 25 is B/A ⁇ 3 or 10 ⁇ B/A.
- Fig. 5 is a graph illustrating a relationship between a sound pressure level (dB) of the sound generated by the air flow and B/A.
- the inventor obtains the following result.
- the sound pressure level is reduced, compared to a case of 3 ⁇ B/A ⁇ 10.
- the sound having a frequency of approximately 1 kHz is particularly reduced.
- the height of the inner peripheral wall portion 18a is higher than the height of the outer peripheral wall portion 18b. In this manner, it is possible to shorten a distance between the discharge-side end portion of the shroud 25 and the upper end portion of the inner peripheral wall portion 18a. As illustrated in Fig. 5 , it is desirable that 1 ⁇ B/A is satisfied, in view of the following facts. In a case of B/A ⁇ 1, compared to a case of 1 ⁇ B/A ⁇ 3, the sound pressure level becomes higher, and the contact caused by the vibration of the bell mouth 12 and the shroud 25 is avoided.
- the second gap B between the discharge-side end portion of the shroud 25 and the inner peripheral wall portion 18a of the drain groove 18 is relatively widened.
- the air is less likely to stagnate on the lower side of the shroud 25, and the airflow is less likely to be separated. Therefore, compared to a case of 3 ⁇ B/A ⁇ 10, the air flows on the lower side of the shroud 25, and the airflow is less likely to be separated. Accordingly, the noise is reduced. As illustrated in Fig. 5 , it is found that the sound pressure level is reduced in a range of 10 ⁇ B/A ⁇ 20.
- the ratio of the second gap B between the discharge-side end portion of the shroud 25 and the inner peripheral wall portion 18a of the drain groove 18 with respect to the first gap A between the upper end portion of the bell mouth 12 and the suction-side end portion of the shroud 25 is B/A ⁇ 3 or 10 ⁇ B/A.
- the noise is reduced, compared to a case of 3 ⁇ B/A ⁇ 10.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Air-Conditioning Room Units, And Self-Contained Units In General (AREA)
- Devices For Blowing Cold Air, Devices For Blowing Warm Air, And Means For Preventing Water Condensation In Air Conditioning Units (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Description
- The present invention relates to a ceiling-cassette air conditioner.
- An indoor unit of a ceiling-cassette air conditioner is internally provided with a centrifugal blower, and a lower surface of the indoor unit has a bell mouth having an opening. A diameter of the opening decreases upward and inward from a suction port. In addition, a drain pan for receiving water condensed and dropped on a surface of a heat exchanger during a cooling operation is installed inside the indoor unit.
- The centrifugal blower has an impeller connected to a rotary shaft. The impeller includes a hub (main plate) installed on an upper portion of the impeller and connected to the rotary shaft, a plurality of blades in which one end side is connected to the hub and the other end side is connected to a shroud, and the shroud that connects the other ends of the blades to each other and whose diameter increases upward and outward from the bell mouth side.
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PTL 1 below discloses that the shroud is installed to be relatively rotatable inside a suction-side end portion of the shroud to maintain a predetermined gap (L1) between the shroud and the bell mouth. - [PTL 1] Japanese Unexamined Patent Application Publication No.
2002-235930 - An upper end portion of a bell mouth is accommodated inside a suction-side end portion of a shroud, and a gap is disposed between the shroud and the bell mouth.
- A drain pan has two side walls (wall portions) to face each of an inside and an outside of a heat exchanger in order to form a drain groove for receiving drain water. A discharge-side end portion of the shroud is located above an inner peripheral wall portion installed inside the heat exchanger in the drain groove, and a gap is disposed between the drain groove and the shroud.
- Accordingly, a suction side of the shroud has a gap from the bell mouth, and a discharge side of the shroud has a gap from the inner peripheral wall portion of the drain groove.
- The inventor has found a fact as follows. If air suctioned by a blower bypasses the blade side without passing through a blade side with respect to the shroud, and passes through the gap between the bell mouth and the shroud, the air causes noise. In addition, the inventor has found another fact as follows. In a case where the air discharged from the blower enters the gap between the shroud and the inner peripheral wall portion of the drain groove, and the air is stagnant or an airflow is separated on a lower side of the shroud, the air also causes the noise.
- The present invention is made in view of the above-described circumstances, and an object thereof is to provide a ceiling-cassette air conditioner capable of reducing noise generated by air suctioned or air discharged by a blower.
- According to an aspect of the present invention, there is provided a ceiling-cassette air conditioner including a heat exchanger, a blower having a tubular shroud having a diameter which increases upward and outward, and installed inside the heat exchanger, a bell mouth installed below the shroud and on a suction side of the blower, and a drain pan having a concave drain groove which accommodates a lower portion of the heat exchanger. A ratio of a second gap B between a discharge-side end portion of the shroud and a side wall of the drain groove inside the heat exchanger with respect to a first gap A between an upper end portion of the bell mouth and a suction-side end portion of the shroud is B/A ≤ 3 or 10 ≤ B/A.
- According to this configuration, noise is reduced, compared to a case where a ratio of the second gap B between the discharge-side end portion of the shroud and an upper end portion of the side wall of the drain groove inside the heat exchanger with respect to the first gap A between the upper end portion of the bell mouth and the suction-side end portion of the shroud is 3 < B/A < 10.
- In the above-described aspect, a height of the side wall of the drain groove inside the heat exchanger may be higher than a side wall of the drain groove outside the heat exchanger.
- According to this configuration, it is possible to shorten a distance between the discharge-side end portion of the shroud and the upper end portion of the side wall inside the drain groove.
- According to the present invention, it is possible to reduce noise generated by air suctioned or air discharged by a blower.
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Fig. 1 is a bottom view illustrating an indoor unit of a ceiling-cassette air conditioner according to an embodiment of the present invention. -
Fig. 2 is a longitudinal sectional view taken along line II-II inFig. 1 . -
Fig. 3 is a plan view illustrating a drain pan according to the embodiment of the present invention. -
Fig. 4 is a partially enlarged longitudinal sectional view illustrating the indoor unit of the ceiling-cassette air conditioner according to the embodiment of the present invention. -
Fig. 5 is a graph illustrating a relationship between a sound pressure level (dB) and a ratio (B/A) of a second gap B between a discharge-side end portion of a shroud and an inner peripheral wall portion of a drain groove with respect to a first gap A between an upper end portion of a bell mouth and a suction-side end portion of the shroud. - Hereinafter, a ceiling-cassette air conditioner according to an embodiment of the present invention will be described with reference to the drawings.
- The ceiling-cassette air conditioner (hereinafter, referred to as an "air conditioner") includes an
indoor unit 1, an outdoor unit (not illustrated), and a refrigerant pipe (not illustrated) that connects theindoor unit 1 and the outdoor unit to each other. - The
indoor unit 1 is installed so that acase body 2 is cassette in a ceiling. As illustrated inFig. 2 , thecase body 2 is internally equipped with aheat exchanger 7, adrain pan 10, amotor 5, ablower 6, and abell mouth 12. Aceiling panel 8 exposed on a ceiling surface is mounted on a lower portion of thecase body 2.Fig. 1 is a bottom view when theindoor unit 1 is viewed from an indoor side, that is, when theindoor unit 1 is viewed from a lower surface of theindoor unit 1.Fig. 2 is a longitudinal sectional view taken along line II-II inFig. 1 . - The
blower 6 is a centrifugal blower, and has animpeller 22 connected to arotary shaft 21. Theimpeller 22 includes a hub (main plate) 23 installed in an upper portion of theimpeller 22 and connected to therotary shaft 21, a plurality ofblades 24 in which one end side is connected to thehub 23 and the other end side is connected to ashroud 25, and theshroud 25 that connects the other ends of theblades 24 to each other and whose diameter increases upward and outward from thebell mouth 12 side. - The
shroud 25 has a tubular shape. In theshroud 25, a radius of a lower portion is larger than a radius of an upper portion, and the radius gradually increases from the lower portion to the upper portion. A suction-side end portion of theshroud 25, that is, a lower end portion is located on an outer peripheral side of thebell mouth 12, and has a gap from thebell mouth 12. In addition, a discharge-side end portion of theshroud 25, that is, an upper end portion is located above an innerperipheral wall portion 18a of adrain groove 18, and has a gap from the innerperipheral wall portion 18a. - The
bell mouth 12 is a tubular member, and is installed below theshroud 25 and on a suction side of theblower 6. In thebell mouth 12, a radius of a lower portion is smaller than a radius of an upper portion, and the radius gradually decreases from the lower portion to the upper portion. An upper end portion of thebell mouth 12 is accommodated inside the suction-side end portion of theshroud 25. - The
drain pan 10 is disposed in a lower portion of theheat exchanger 7, and receives drain water dropped from theheat exchanger 7. Thebell mouth 12 is disposed in a lower portion of thedrain pan 10. Asuction port 3 is formed in a central portion on a lower surface of theindoor unit 1, and adischarge port 4 is formed adjacent to thesuction port 3 and along an outer peripheral portion on the lower surface of theindoor unit 1. Asuction grill 11 and afilter 13 disposed above thesuction grill 11 are installed in thesuction port 3. - When the air conditioner is operated, refrigerant from an outdoor unit (not illustrated) circulates through the
heat exchanger 7, and theblower 6 is driven by themotor 5. Since theblower 6 is driven, indoor air is guided to thebell mouth 12 from thesuction port 3 through thesuction grill 11 and thefilter 13, and is suctioned into theblower 6. Then, the suctioned air passes through theheat exchanger 7. In this manner, the suctioned air is cooled or heated, and thereafter is discharged indoor through thedischarge port 4. - For example, the
drain pan 10 is made of styrene foam, and a surface for storing the drain water is coated with a waterproof paint. As illustrated inFig. 3 , a shape of thedrain pan 10 in a plan view is a substantially quadrangular shape.Openings drain pan 10 to correspond to thesuction port 3 and thedischarge port 4. Abottom portion 10a of thedrain pan 10 is disposed over an entire region having theheat exchanger 7 installed therein, along a lower portion of theheat exchanger 7 disposed to surround theblower 6.Fig. 3 is a plan view illustrating thedrain pan 10. - As illustrated in
Fig. 2 , aconcave drain groove 18 is formed in thedrain pan 10, and the drain water is accumulated inside thedrain groove 18. As illustrated inFigs. 2 and3 , thedrain groove 18 has an innerperipheral wall portion 18a formed inside theheat exchanger 7, that is, on an inlet side of theheat exchanger 7, and an outerperipheral wall portion 18b formed outside theheat exchanger 7, that is, on an outlet side of theheat exchanger 7. As illustrated inFig. 3 , the innerperipheral wall portion 18a is disposed along theopening 16 formed corresponding to thesuction port 3. The outerperipheral wall portion 18b is disposed along theopening 17 formed corresponding to thedischarge port 4. - As illustrated in
Fig. 2 , the lower portion of theheat exchanger 7 is accommodated in thedrain groove 18, and a height position of a lower end of theheat exchanger 7 is lower than an upper end of thedrain groove 18. In this manner, the outerperipheral wall portion 18b of thedrain groove 18 prevents the drain water adhering to the lower portion of theheat exchanger 7 from being scattered outward. - As illustrated in
Figs. 2 and3 , aconvex portion 19 protruding upward is formed in thebottom portion 10a of thedrain pan 10. Theheat exchanger 7 is placed on an upper surface of theconvex portion 19. Theconvex portion 19 is formed corresponding to a shape of a bottom surface of theheat exchanger 7 along the bottom surface of theheat exchanger 7 so that a gap from theheat exchanger 7 is not formed as far as possible. - In the
bottom portion 10a of the above-describeddrain pan 10, as illustrated inFig. 2 , it is desirable that thebottom portion 10a outside theheat exchanger 7 is formed at a lower position than thebottom portion 10a inside theheat exchanger 7. In this manner, the water accumulated in thedrain pan 10 is easily guided outward from the inside of theheat exchanger 7. In addition, in theindoor unit 1, theblower 6 is disposed inside theheat exchanger 7. A wind flow from theblower 6 is oriented outward from the inside of theheat exchanger 7. Accordingly, the drain water accumulated in thedrain pan 10 is easily discharged outward from the inside of theheat exchanger 7 by using a wind force. - As illustrated in
Fig. 2 , aninsulation 20 is installed between a lower portion of theheat exchanger 7 and an upper surface of theconvex portion 19. In this manner, a space between theheat exchanger 7 and theconvex portion 19 is closed by theinsulation 20. Accordingly, it is possible to reduce the air flowing outward from the inside of theheat exchanger 7 after passing through a gap without passing through theheat exchanger 7. In addition, since theinsulation 20 is installed between the lower portion of theheat exchanger 7 and the upper surface of theconvex portion 19, theinsulation 20 is accommodated in thedrain groove 18. Therefore, even the drain water dropped from theheat exchanger 7 and adhering to theinsulation 20 is prevented from being scattered outward. - Next, referring to
Figs. 4 and5 , a relationship between a first gap A between the upper end portion of thebell mouth 12 and the suction-side end portion of theshroud 25 and a second gap B between the discharge-side end portion of theshroud 25 and the innerperipheral wall portion 18a of thedrain groove 18 will be described. - In the present embodiment, a ratio of the second gap B between the discharge-side end portion of the
shroud 25 and the innerperipheral wall portion 18a of thedrain groove 18 with respect to the first gap A between the upper end portion of thebell mouth 12 and the suction-side end portion of theshroud 25 is B/A ≤ 3 or 10 ≤ B/A. -
Fig. 5 is a graph illustrating a relationship between a sound pressure level (dB) of the sound generated by the air flow and B/A. The inventor obtains the following result. In a case of B/A ≤ 3 or 10 ≤ B/A, as illustrated inFig. 5 , the sound pressure level is reduced, compared to a case of 3 < B/A <10. In addition, it is confirmed that the sound having a frequency of approximately 1 kHz is particularly reduced. - Since B/A ≤ 3 is set, the first gap A between the upper end portion of the
bell mouth 12 and the suction-side end portion of theshroud 25 is relatively narrowed. As a result, the air suctioned in by theblower 6 is less likely to pass through the gap between thebell mouth 12 and theshroud 25, and the more air passes through theblade 24 side with respect to theshroud 25. Therefore, compared to a case where 3 < B/A, the air that bypasses theblade 24 side without passing through theblade 24 side with respect to theshroud 25 and passes through the gap between thebell mouth 12 and theshroud 25 is reduced. Therefore, noise is reduced. - In a case of B/A ≤ 3, as in an example illustrated in
Fig. 2 , the height of the innerperipheral wall portion 18a is higher than the height of the outerperipheral wall portion 18b. In this manner, it is possible to shorten a distance between the discharge-side end portion of theshroud 25 and the upper end portion of the innerperipheral wall portion 18a. As illustrated inFig. 5 , it is desirable that 1 ≤ B/A is satisfied, in view of the following facts. In a case of B/A < 1, compared to a case of 1 ≤ B/A ≤ 3, the sound pressure level becomes higher, and the contact caused by the vibration of thebell mouth 12 and theshroud 25 is avoided. - In addition, since 10 ≤ B/A is set, the second gap B between the discharge-side end portion of the
shroud 25 and the innerperipheral wall portion 18a of thedrain groove 18 is relatively widened. As a result, even if the air discharged from theblower 6 enters the gap between theshroud 25 and the innerperipheral wall portion 18a of thedrain groove 18, the air is less likely to stagnate on the lower side of theshroud 25, and the airflow is less likely to be separated. Therefore, compared to a case of 3 < B/A < 10, the air flows on the lower side of theshroud 25, and the airflow is less likely to be separated. Accordingly, the noise is reduced. As illustrated inFig. 5 , it is found that the sound pressure level is reduced in a range of 10 ≤ B/A ≤ 20. - As described above, according to the present embodiment, the ratio of the second gap B between the discharge-side end portion of the
shroud 25 and the innerperipheral wall portion 18a of thedrain groove 18 with respect to the first gap A between the upper end portion of thebell mouth 12 and the suction-side end portion of theshroud 25 is B/A ≤ 3 or 10 ≤ B/A. The noise is reduced, compared to a case of 3 < B/A < 10. -
- 1:
- indoor unit
- 2:
- case body
- 3:
- suction port
- 4:
- discharge port
- 5:
- motor
- 6:
- blower
- 7:
- heat exchanger
- 8:
- ceiling panel
- 10:
- drain pan
- 10a:
- bottom portion
- 11:
- suction grill
- 12:
- bell mouth
- 13:
- filter
- 16, 17:
- opening
- 18:
- drain groove
- 18a:
- inner peripheral wall portion
- 18b:
- outer peripheral wall portion
- 19:
- convex portion
- 20:
- insulation
- 21:
- rotary shaft
- 22:
- impeller
- 23:
- hub
- 24:
- blade
- 25:
- shroud
- A:
- first gap
- B:
- second gap
Claims (2)
- A ceiling-cassette air conditioner comprising:
a heat exchanger;
a blower having a tubular shroud having a diameter which increases upward and outward, and installed inside the heat exchanger;
a bell mouth installed below the shroud and on a suction side of the blower; and
a drain pan having a concave drain groove which accommodates a lower portion of the heat exchanger,
wherein a ratio of a second gap B between a discharge-side end portion of the shroud and a side wall of the drain groove inside the heat exchanger with respect to a first gap A between an upper end portion of the bell mouth and a suction-side end portion of the shroud is B/A ≤ 3 or 10 ≤ B/A. - The ceiling-cassette air conditioner according to claim 1, wherein a height of the side wall of the drain groove inside the heat exchanger is higher than a side wall of the drain groove outside the heat exchanger.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018013680A JP7278710B2 (en) | 2018-01-30 | 2018-01-30 | Ceiling-mounted air conditioner |
PCT/JP2018/041452 WO2019150691A1 (en) | 2018-01-30 | 2018-11-08 | Ceiling-embedded air conditioner |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3748238A1 true EP3748238A1 (en) | 2020-12-09 |
EP3748238A4 EP3748238A4 (en) | 2021-10-20 |
Family
ID=67478745
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18904199.9A Pending EP3748238A4 (en) | 2018-01-30 | 2018-11-08 | Ceiling-embedded air conditioner |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP3748238A4 (en) |
JP (1) | JP7278710B2 (en) |
CN (1) | CN212746683U (en) |
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Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH11101194A (en) * | 1997-09-30 | 1999-04-13 | Daikin Ind Ltd | Centrifugal blower and air conditioner with the centrifugal blower |
JP3807101B2 (en) * | 1998-06-19 | 2006-08-09 | 株式会社富士通ゼネラル | Embedded ceiling air conditioner |
JP2002235930A (en) | 2001-02-09 | 2002-08-23 | Daikin Ind Ltd | Air conditioner |
AU2003284610B2 (en) * | 2002-12-16 | 2006-11-16 | Daikin Industries, Ltd. | Centrifugal fan, and air conditioner provided therewith |
KR100782195B1 (en) * | 2006-08-10 | 2007-12-04 | 엘지전자 주식회사 | Air conditioner |
JP2010138700A (en) | 2008-12-09 | 2010-06-24 | Daikin Ind Ltd | Centrifugal blower |
JP2013108684A (en) | 2011-11-22 | 2013-06-06 | Hitachi Appliances Inc | Indoor unit of air conditioner |
JP5641089B2 (en) * | 2013-04-30 | 2014-12-17 | ダイキン工業株式会社 | Decorative panel and air conditioner indoor unit equipped with the same |
JP2015114089A (en) * | 2013-12-16 | 2015-06-22 | 三星電子株式会社Samsung Electronics Co.,Ltd. | Ceiling recessed indoor unit and air conditioner using same |
JP2016011827A (en) * | 2014-06-05 | 2016-01-21 | 三星電子株式会社Samsung Electronics Co.,Ltd. | Ceiling embedded type indoor equipment and air conditioner using the same |
WO2016084216A1 (en) * | 2014-11-28 | 2016-06-02 | 日立アプライアンス株式会社 | Indoor unit for air conditioner |
CN107850318B (en) | 2015-07-08 | 2020-06-26 | 日立江森自控空调有限公司 | Indoor unit of air conditioner |
JP2017215091A (en) * | 2016-05-31 | 2017-12-07 | 日立ジョンソンコントロールズ空調株式会社 | Indoor machine of air conditioner |
-
2018
- 2018-01-30 JP JP2018013680A patent/JP7278710B2/en active Active
- 2018-11-08 CN CN201890001506.6U patent/CN212746683U/en active Active
- 2018-11-08 WO PCT/JP2018/041452 patent/WO2019150691A1/en unknown
- 2018-11-08 EP EP18904199.9A patent/EP3748238A4/en active Pending
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JP7278710B2 (en) | 2023-05-22 |
CN212746683U (en) | 2021-03-19 |
JP2019132475A (en) | 2019-08-08 |
WO2019150691A1 (en) | 2019-08-08 |
EP3748238A4 (en) | 2021-10-20 |
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