JP2006046170A - Duct fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To respond a complaint that it is difficult to secure dimension of a roof space in a high-rise apartment in recent years due to market trend of keeping height of a roof from a floor surface is large to show an inside of a room wide and an exhaust fan put in a low roof space is demanded. <P>SOLUTION: A duct fan provided with a single suction type blower in a flow passage of a box shape machine body, a motor in the flow passage of a fan suction opening side, a fan casing side plate in an anti-motor side of the single suction type blower to oppose vicinity of roof surface plate of the machine body, a fan discharge opening partition wall partitioning between a machine body blow out opening and the fan discharge opening with including an opening part of the fan discharge opening between the machine body blow out opening and the fan discharge opening of the single suction type blower, and a suction air chamber reducing delivery resistance of delivery flow from the fan delivery opening, is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a duct fan that is arranged in a space such as a ceiling of a building and is used for exhaust ventilation from a room to a room through a duct, and is particularly installed in a narrow space behind the ceiling of a high-rise apartment or the like.

  Conventionally, as an example of a duct fan in a general non-residential space, those shown in FIGS. 10, 11, and 12 are known. Hereinafter, the configuration will be described with reference to FIG. 10, FIG. 11, and FIG. As shown in FIG. 10 and FIG. 11, there is a box-shaped airframe 106 that is installed by connecting a suction side duct 103 to the airframe inlet 102 and a blowout side duct 105 to the airframe outlet 104 in the deep ceiling 101. . The airframe 106 has a structure in which a body air inlet 102 is provided on the suction side, a body air outlet 104 is provided on the discharge side, and a single suction fan 108 having a fan casing 107 inside the airframe 106 is provided. When the airframe 106 is operated, dirty air in the room 109 is sucked into the airframe 106 through the suction side duct 103, passes through the single suction fan 108 and the blowout side duct 105, and is then discharged to the outdoor 110. (For example, see Patent Document 1).

10 has a motor 111 in the airframe 106. As shown in FIG. 12, there is a case in which the motor 111 is disposed outside the airframe 106. The height dimension H112 of the included main body is substantially the same (for example, refer to Patent Document 2 or Patent Document 3).
JP 59-27199 A Japanese Patent Laid-Open No. 04-309738 JP 11-324990 A

  A duct fan as such a conventional non-residential exhaust device requires an air passage for increasing the suction flow component in the direction of the central axis of the impeller at the fan suction port, and is blown out from the fan discharge port. Therefore, the height of the main body is inevitably high because the positions of the fan discharge port and the main body outlet are aligned. However, in recent years, in high-rise apartments, it is difficult to ensure the dimensions of the ceiling because of the market trend that makes the floor space high from the ceiling in order to make the interior wide. Yes.

  Therefore, the present invention solves such a conventional problem, and an object of the present invention is to provide a compact duct fan incorporating a single suction fan.

  The present invention according to claim 1 has a flow path from the fuselage inlet to the fuselage outlet in a box-shaped fuselage having a pair of fuselage inlets and fuselage outlets facing each other. A single-suction blower is provided in the path, and the single-suction blower is a duct fan in which a motor is disposed on the fan suction port side so that the motor faces the flow path, and is opposite to the single-suction blower. The fan casing side plate on the motor side is opposed to the vicinity of the top plate of the fuselage, and between the fuselage outlet and the fan outlet of the single-suction fan, the fan outlet is between the fuselage outlet and the fan outlet. A fan discharge port partition partitioned by having an opening is provided, and a blowout air chamber for reducing discharge resistance of a discharge flow from the fan discharge port is provided.

  The present invention according to claim 2 includes a box-shaped airframe having a pair of airframe inlets and airframe outlets facing each other, and has a flow path from the airframe inlet to the airframe outlet. A single-suction blower is provided in the path, and the single-suction blower is a duct fan having a motor on the fan suction port side, facing the motor into the flow path, and having a drain pan at the bottom of the main body. The fan casing side plate on the side opposite to the motor of the single-suction blower is opposed to the vicinity of the top plate of the fuselage, and between the fuselage outlet and the fan discharge port of the single-suction blower, A fan discharge port partition that is partitioned from the outlet with an opening of the fan discharge port is provided, and a blowout air chamber that reduces discharge resistance of the discharge flow from the fan discharge port is provided, and the drain pan is a drain receiver. And the fan inlet channel Characterized in that it was I with shape.

  According to a third aspect of the present invention, a box-shaped airframe having a fuselage inlet and a fuselage outlet has a flow path from the fuselage suction opening to the fuselage blowout outlet, and a single suction blower is provided in the flow path. The single-suction blower is a duct fan having a motor on the fan suction port side, facing the motor into the flow path, and having a drain pan at the bottom of the main body. The counter-motor side casing side plate is opposed to the vicinity of the top plate of the fuselage, and between the fuselage outlet and the fan outlet of the single-suction blower, the fan outlet is located between the fuselage outlet and the fan outlet. A fan discharge port partition partitioned by an opening is provided, a blowout air chamber for reducing discharge resistance of a discharge flow from the fan discharge port is provided, and a plurality of airframe suction ports are formed.

  According to a fourth aspect of the present invention, in the duct fan according to the third aspect, each of the three side wall surfaces of the box-shaped main body has airframe inlets.

  According to a fifth aspect of the present invention, in the duct fan according to the first to fourth aspects, the fuselage outlet is arranged in an extension line shape of the extension plate of the scroll of the fan discharge port.

  According to a sixth aspect of the present invention, in the duct fan according to the first to fifth aspects of the present invention, a fan discharge port partition wall is provided in which the fan discharge port is partitioned between the fuselage outlet and the fan discharge port. A sound absorbing material is provided on the inner surface of the blowing air chamber for reducing the discharge resistance of the discharge flow from the fan discharge port.

  According to a seventh aspect of the present invention, in the duct fan according to the first to fifth aspects, a sound absorbing material is provided on the inner surface on the airframe inlet side.

  As described above, according to the present invention, the blowout air chamber is provided between the fan discharge port and the fuselage blowout port of the single-suction blower, so that the blowout resistance is reduced, and it fits in a low ceiling behind a high-rise apartment. It is possible to provide a thin duct fan.

  In the first embodiment of the present invention, a single suction type blower is provided in the flow path of the box-shaped airframe, a motor is disposed in the flow path on the fan suction port side, and the motor is disposed in the flow path. The fan casing side plate on the side opposite to the motor of the single-suction fan is opposed to the vicinity of the top plate of the fuselage, and between the blower outlet and the fan discharge port of the single-suction blower. A fan discharge port partition that has an opening of the fan discharge port between the fuselage discharge port and the fan discharge port, and has a blowout air chamber that reduces discharge resistance of the discharge flow from the fan discharge port This is a configuration. As a result, the blade width of the single-suction blower is reduced to reduce the height of the fuselage, so that the blade diameter is increased to ensure the blowing capacity, and the inspection port and the bottom surface of the fuselage are aligned. Thus, the discharge resistance of the discharge flow from the fan discharge port due to the misalignment between the center of the fan discharge port and the center of the box-shaped airframe can be reduced from the fan discharge port by the blowout air chamber provided between the machine discharge port and the fan discharge port. By reducing the discharge resistance of the discharge flow and securing the air blowing capability, it is possible to reduce the height of the machine body.

  In the second embodiment of the present invention, a single suction type blower is provided in the flow path of the box-shaped airframe, a motor is disposed in the flow path on the fan suction port side, and the motor is disposed in the flow path. A duct fan having a drain pan at the bottom of the main body, the fan casing side plate on the side opposite to the motor of the single-suction blower facing the top plate of the fuselage, and the blower outlet and the single-suction blower A fan discharge partition wall is provided between the air discharge port and the fan discharge port, the fan discharge port partitioning the fan discharge port with an opening, and discharge resistance of the discharge flow from the fan discharge port The drain pan is configured to have a shape having both a drain receiving portion and a fan suction port flow path. As a result, it is possible to reduce the height of the fuselage by the configuration having both functions of the ventilation passage and the drain receiving portion of the drain receiving portion.

  In the third embodiment of the present invention, a single suction blower is provided in the flow path of the box-shaped airframe, a motor is disposed in the flow path on the fan suction port side, and the motor is exposed in the flow path. A duct fan having a drain pan at the bottom of the main body, wherein a fan discharge port partition is provided between the fuselage outlet and the fan discharge port of the single suction blower, and a discharge flow from the fan discharge port The blower air chamber for reducing the discharge resistance is further provided, and the airframe suction port is constituted by a plurality. As a result, exhaust from a plurality of locations requiring exhaust can be concentrated and ventilation of many rooms is possible with a small number of exhaust devices.

  In the duct fan of the third embodiment, the fourth embodiment of the present invention is configured such that each of three different side wall surfaces of the box-shaped main body has an air inlet. Thereby, when exhaust is required, exhaust from three locations can be concentrated.

  In the duct fan of the first to fourth embodiments, the fifth embodiment of the present invention has a configuration in which a fuselage outlet is arranged in an extension line shape of the extension plate of the scroll of the fan discharge port. is there. Thereby, since the resistance of the discharge flow blown out from the fan discharge port can be relaxed, it is possible to secure the blowing capacity of the single suction type blower necessary for exhaust and to achieve miniaturization.

  The sixth embodiment of the present invention is a fan discharge port in the duct fan according to the first to fifth embodiments, in which the fan discharge port is partitioned between the fuselage discharge port and the fan discharge port. A partition is provided, and a sound absorbing material is provided on the inner surface of the blowing air chamber for reducing the discharge resistance of the discharge flow from the fan discharge port. Thereby, the noise which generate | occur | produced from the single suction type air blower in the blowing air chamber can be reduced.

  In the duct fan according to the first to fifth embodiments, the seventh embodiment of the present invention is configured to have a sound absorbing material on the inner surface on the airframe inlet side. Thereby, the noise generated from the single suction blower can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
A first embodiment of the present invention will be described with reference to FIGS. 1 is a side sectional view of a first embodiment of the present invention, FIG. 2 is a plan sectional view of the first embodiment of the present invention, and FIG. 3 is a side view showing an installation state of the first embodiment of the present invention.

  As shown in the side sectional view of FIG. 1, a pair of box-shaped airframes 3 are provided on two surfaces facing the airframe inlet 1 and the airframe outlet 2. The airframe 3 is provided with a suction adapter 5 that connects the suction side duct 4 to the airframe suction port 1 and a blowout adapter 7 that connects the blowout side duct 6 to the airframe blowout port 2. Inside the airframe 3, there is a flow path 8 from the airframe inlet 1 to the airframe outlet 2, and a single suction blower 9 is built in the flowpath 8. The single suction blower 9 has a motor 12 with an impeller 11 attached to the fan suction port 10 side, and the fan casing side plate 13 on the side opposite to the motor of the single suction blower 9 is opposed to the vicinity of the top plate 14 of the fuselage 3. Attached. The motor 12 is disposed in the flow path 8. The single suction blower 9 uses a fan casing width 15 smaller than the diameter of the air blower outlet 2, and the fan discharge port center 16 is shifted from the blowout duct center 17 toward the top plate 14. Therefore, on the side surface of the machine body, the fan discharge port 18 and the machine air outlet 2 are arranged at a shifted position.

  2, the airframe inlet 1 and the air outlet 2 are disposed on the center line 26 of the airframe 3. This is because the airframe inlet 1 and the air outlet 2 are more commonly used in the construction plan of air-conditioning equipment construction than when the airline center line 26 is aligned with the center line of the air duct pipe when designing the equipment and air duct pipe. This is because it is a limiting condition to be provided in the center line 26 of the airframe. This practice is easy to design so as to ensure the dimensional relationship between the plane of the airframe 3 and the duct connected to the airframe 3 and the positional relationship with the ceiling inspection port 40 attached to the lower portion of the airframe 3. It is to do.

  Here, in order to arrange the scroll 27 of the single suction fan 9 close to the side wall plate 22 of the machine body 3, the fan discharge port 18 of the single suction fan 9 is located at a position shifted from the center line 26 of the machine body. However, since the air outlet 2 is provided on the center line 26 of the airframe, the fan discharge port 18 and the air outlet 2 have a different structure on the plane of the airframe. Further, the use of the fan casing width 15 that is smaller than the diameter of the air blower outlet 2 in the single suction type blower 9 increases the diameter of the blade by reducing the blade width, thereby increasing the degree of difference.

  For this reason, the fan discharge port partition 19 having an opening portion of the fan discharge port 18 is connected to the fan discharge port 18 of the single suction blower 9 with respect to the deviation between the fan discharge port 18 and the body discharge port 2. A blower air chamber 23, which is a space provided by facing the side plate 20 and surrounded by the fan discharge port partition wall 19, the fuselage outlet side plate 20, the top plate 14, the drain pan 21 and the side wall plate 22, is provided in the fan discharge port 18. And the airframe outlet side plate 20.

  Further, on the plane of the body 3, the scroll extension plate 28-1 is placed on the line 32 at the shortest distance end portion connecting the fan discharge port end portion 30 and the airframe outlet end portion 31 on the high-speed discharge airflow portion 29 side or inside thereof. Oriented towards That is, the scroll extension plate 28-1 of the single-suction blower 9 is provided with an inclination angle in the direction of the center line 26 of the machine body so that the high-speed discharge airflow portion 29 from the fan discharge port 18 does not collide with the machine body outlet side plate 20. It is arranged so as to flow into the air outlet 2.

  The shape of the fan discharge port partition wall 19 is an integral structure formed by bending the scroll extension plate 28-1 of the single suction blower 9 from the fan discharge port 18 toward the side wall plate 22. Further, in the shape of the fan discharge port partition wall 19, an integral structure is formed by bending the tongue portion 28-2 toward the side wall plate 22. For this reason, the number of parts can be reduced, and inexpensive production is possible.

  When the duct fan is operated in the above configuration, as shown in FIG. 3, the single suction fan 9 built in the airframe 3 installed in the ceiling 33 is operated, and the air in the room 34 flows through the suction duct 4 and flows. The air is sucked into the single suction blower 9 via the path 8, and is exhausted to the outdoor 35 through the blowout duct 6 via the blowout air chamber 23.

  As shown in FIG. 1 and FIG. 2, the airflow sucked from the machine body suction port 1 flows in the direction of the motor lower part A, and the central axis of the impeller 11 of the single suction blower 9. Is sucked in the direction of, and flows into the fan inlet 10. The airflow blown out from the fan discharge port 18 is blown out toward the machine body outlet 2 located obliquely below and connected in the space of the blowout air chamber 23. Here, the high-speed discharge airflow portion 29 discharged from the fan discharge port 18 in both the cross section of FIG. 1 and the plane of FIG. 2 has a structure in which the fan discharge port 18 and the fuselage outlet 2 have a different structure, The space of the blowout air chamber 23 is used as a flow path, and the scroll extension plate 28-1 is directed to the line 32 at the shortest distance end portion connecting the fan discharge port end portion 30 and the fuselage outlet end portion 31 or toward the inside thereof. The airflow is collected in the airframe outlet 2 without the airflow colliding with the airframe outlet side plate 20. For this reason, the discharge resistance of the fan discharge port 18 is reduced, the reduction of the air volume can be reduced as much as possible, and the air volume characteristics of the single suction fan 9 can be secured. Therefore, the duct capable of reducing the height H1 of the airframe 3 can be achieved. Fans can be provided. The difference in structure here shows a deviation between the fan outlet center 16 and the outlet duct center 17 in both FIGS.

  In addition, since the fan casing 36 of the single-suction blower 9 is arranged so as to be biased upward from the center of the airframe suction port 1, the air entering from the airframe suction port 1 does not directly hit the back surface of the fan casing 36. Therefore, the resistance of the suction part is reduced.

  When maintenance is performed, the ceiling inspection port 40 provided in the ceiling material 39 is opened just below the airframe 3, the drain pan 21 is removed by removing the drain pan 21, and the motor 12 and the impeller 11 inside are removed. Inspection to. And since the motor 12 is arrange | positioned at the drain pan 21 side, the drain pan 21 can be removed from the ceiling inspection port 40, and the duct fan which can check the motor 12 and the impeller 11 simultaneously can be provided.

  It should be noted that the angle θ between the scroll extension plate 28-1 of the single suction blower 9 and the center line 26 of the airframe, and the length dimension L between the fan discharge port 18 and the airframe outlet side plate 20 of the blowout air chamber 23. In relation to the above, it is desirable that the length L is 40 mm or more with respect to the angle θ of 30 ° or less.

(Example 2)
The second embodiment is different from the first embodiment in that the drain pan 21 at the bottom of the machine body 3 has a configuration in which the drain receiving portion 25 and the fan inlet channel 37 are combined. The other symbols and explanation of the first embodiment are omitted.

  FIG. 4 is a side sectional view of Embodiment 2 of the present invention. As shown in FIG. 4, a drain pan 21 having a gradient is provided at the bottom of the body 3 up to a drain plug 24 provided at the lowest position of the end. The drain pan 21 includes a quadrangular drain receiving portion 25 having an internal space for collecting drain water. The motor lower part A is located in a lower part from the upper end line B of the drain receiving part 25.

  When the duct fan is operated here, the airflow sucked from the airframe suction port 1 flows in the direction of the drain pan 21 located in the lower part A of the motor, and has a rectangular shape with a fan suction port channel 37 provided with a space near the fan suction port 10. It flows into the flow path 8 also having the drain receiving portion 25 and flows into the fan suction port 10 through the space in front of the fan suction port 10 necessary for sucking in the direction of the central axis of the impeller 11 of the single suction blower 9. .

  For this reason, the space in front of the fan suction port 10 becomes the flow path 8 space simultaneously with the drainage space of the drain pan 21, and the suction space in front of the fan suction port 10 can be secured while securing the capacity of the drain pan 21. The height dimension H2 of the airframe 3 can be suppressed without impairing the ability. For this reason, the height dimension H2 of the second embodiment is smaller than the height dimension H1 of the first embodiment, and the thickness can be further reduced.

(Example 3)
In the third embodiment, the second machine body suction port 41 and the third machine body suction port 42 are added to the different side wall plates 22 of the box-shaped machine body 3 with respect to the first embodiment. The symbols and description about the first embodiment will be omitted.

  FIG. 5 is a side sectional view of the third embodiment of the present invention, and FIG. 6 is a plan sectional view of the third embodiment of the present invention. As shown in FIGS. 5 and 6, the second airframe suction port 41 and the third airframe outlet 42 are provided on the two opposite surfaces of the side wall plate 22 different from the airframe suction port 1. The suction adapter 5 that connects the suction side duct 4 to the fuselage suction port 1, the second suction adapter 44 that connects the second suction side duct 43 to the second fuselage suction port 41, and the third fuselage suction port 42 The 3rd suction adapter 46 which connects the 3 suction side duct 45, and the blowing adapter 7 which connects the blowing side duct 6 to the body blower outlet 2 are arranged. Therefore, the airframe 3 has a flow path 8 extending from the airframe inlet 1, the second airframe inlet 41, and the third airframe inlet 42 to the airframe outlet 2. As a result, it is possible to exhaust air from three places with one duct fan. Moreover, a common shape can be used for the suction adapter attached to the suction port and the blowout adapter attached to the airframe outlet.

  In addition, as shown in FIG. 7, the second machine body suction port 41 or the third machine body suction port 42 may be removed from the box-shaped machine body 3.

Example 4
8 is a side sectional view of the fourth embodiment of the present invention, and FIG. 9 is a plan sectional view of the fourth embodiment of the present invention. As shown in FIGS. 8 and 9, a fan discharge partition wall 19 having an opening of the fan discharge port 18 is provided between the fuselage outlet 2 and the fan discharge port 18, so that the discharge flow from the fan discharge port 18 can be reduced. A blowing-side sound absorbing material 47 is provided on the inner surface of the blowing air chamber 23 for reducing the discharge resistance, and a suction-side sound absorbing material 48 is provided on the inner surface of the machine body suction port 1. The noise generated from the single suction blower 9 is absorbed by the blowing side sound absorbing material 47 on the inner surface of the blowing air chamber 23 and is also absorbed by the suction side sound absorbing material 48 on the inner surface of the fuselage suction port 1. Fans can be provided.

  The present invention can also be applied to supply air ventilation other than exhaust ventilation.

Side surface sectional drawing of Example 1 of this invention Plan sectional drawing of Example 1 of this invention The side view which shows the installation state of Example 1 of this invention Side surface sectional drawing of Example 2 of this invention Side surface sectional drawing of Example 3 of this invention Plan sectional drawing of Example 3 of this invention Plan sectional drawing of Example 3 which removed the 3rd airframe inlet of this invention Side surface sectional drawing of Example 4 of this invention Plan sectional drawing of Example 4 of this invention Side sectional view of Conventional Example 1 Side view showing the installation state of Conventional Example 1 Side sectional view of Conventional Example 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airframe inlet 2 Airframe outlet 3 Airframe 4 Suction side duct 5 Suction adapter 6 Air outlet side duct 7 Air outlet adapter 8 Flow path 9 Single suction fan 10 Fan inlet 11 Impeller 12 Motor 13 Fan casing side plate 14 on the non-motor side Top plate 15 Fan casing width 16 Fan discharge port center 17 Blower side duct center 18 Fan discharge port 19 Fan discharge port bulkhead 20 Airframe outlet side plate 21 Drain pan 22 Side wall plate 23 Blow air chamber 24 Drain plug 25 Drain receiving portion 26 Center of airframe Line 27 Scroll 28-1 Scroll extension plate 28-2 Tongue portion 29 High-speed discharge airflow portion 30 Fan discharge port end portion 31 Aircraft blowout end portion 32 Line at the shortest distance end 33 Ceiling back 34 Indoor 35 Outdoor 36 Fan casing 37 Fan inlet channel L Length Method θ Angle A Lower part of motor B Upper end line H1, H2 Height dimension 39 Ceiling material 40 Ceiling inspection port 41 Second body suction port 42 Third body suction port 43 Second suction side duct 44 Second suction adapter 45 Third suction Side duct 46 Third suction adapter 47 Blow-out side sound absorbing material 48 Suction side sound absorbing material

Claims (7)

A box-shaped body having a pair of airframe inlets and airframe outlets facing each other has a flow path from the airframe inlet to the airframe outlet, and a single suction type blower is provided in the flow path, The single suction type blower is a duct fan in which a motor is disposed on the fan suction port side, and the motor faces the flow path, and the fan casing side plate on the side opposite to the motor of the single suction type blower is connected to the airframe. Facing the vicinity of the top plate, and between the fuselage outlet and the fan outlet of the single-suction blower, the gap between the fuselage outlet and the fan outlet is divided with an opening of the fan outlet. A duct fan comprising a blow-off air chamber provided with a fan discharge port partition and reducing discharge resistance of a discharge flow from the fan discharge port. In a box-shaped body having a pair of airframe inlet and airframe outlet on opposite sides, it has a flow path from the airframe inlet to the airframe outlet, and a single suction fan is provided in the flow path, The single-suction blower is a duct fan having a motor on the fan suction port side, facing the motor in the flow path, and having a drain pan at the bottom of the main body, the counter-motor of the single-suction blower The side fan casing side plate faces the top plate near the fuselage, and between the fuselage outlet and the fan outlet of the single-suction blower, between the fuselage outlet and the fan outlet, A fan discharge port partition that is partitioned with an opening is provided, and a blowout air chamber that reduces discharge resistance of the discharge flow from the fan discharge port is provided, and the drain pan has both a drain receiving portion and a fan suction port channel The shape Duct fan according to claim. A box-shaped airframe having a body air inlet and a body air outlet has a flow path from the air body inlet to the air body outlet, and a single suction type blower is provided in the flow path, and the single suction fan is a fan A duct fan having a motor disposed on the suction port side, facing the motor into the flow path, and having a drain pan at the bottom of the main body, the non-motor side casing side plate of the single-suction blower A fan that opposes the vicinity of the top plate and divides between the fuselage outlet and the fan discharge port with an opening of the fan discharge port between the fuselage outlet and the fan discharge port of the single suction fan A duct fan comprising: a discharge port partition wall; a blowout air chamber for reducing discharge resistance of a discharge flow from the fan discharge port; and a plurality of airframe suction ports. 4. The duct fan according to claim 3, wherein each of the three side wall surfaces of the box-shaped main body has a fuselage suction port. The duct fan according to any one of claims 1 to 4, wherein a fuselage outlet is disposed in an extended line shape of the extension plate of the scroll of the fan discharge port. Provided with a fan discharge port partition that has an opening of the fan discharge port between the air blower outlet and the fan discharge port, and is provided on the inner surface of the blowout air chamber that reduces discharge resistance of the discharge flow from the fan discharge port. The duct fan according to claim 1, further comprising a sound absorbing material. The duct fan according to any one of claims 1 to 5, further comprising a sound absorbing material on an inner surface of the machine body inlet side.

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