JP2007285164A - Sirocco fan and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sirocco fan which has a large amount of a blowout air volume as compared to a sirocco fan with a nearly-circular-shape suction opening at the same revolution speed. <P>SOLUTION: The sirocco fan is equipped with a scroll casing 20 which is formed in a whorl from a starting point 20a of a scroll shape and is formed with a blowout flow path 24 along an inside of an outer circumferential wall, a fan 10 housed in the scroll casing 20, a suction opening 21 which is provided in the scroll casing 20 to open in a rotation axis direction of the fan 10, a blowout hole 22 which opens in a circumferential direction of the fan 10 and is located at a downstream end of the whorl-like blowout flow path 24. At least part of the suction opening 21 at a side nearer to the blowout hole 22 than a straight line 23 connecting the starting point 21a of a scroll shape and a center 1 of a fan rotary axis is allowed to protrude to the side of the blowout hole 22 as compared to the case where the suction opening 21 is nearly-circular-shaped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sirocco fan in which the amount of blown air is increased and an air conditioner using the sirocco fan.

  Conventionally, as a sirocco fan, an impeller is accommodated in a casing having an inlet and an outlet. When the sirocco fan operates, air is sucked in from the suction port of the casing that opens in the direction of the rotation axis of the impeller, and this sucked air is blown out from the blower outlet of the casing that opens in the circumferential direction of the impeller. The suction port of the casing has a circular shape concentric with the rotating shaft of the impeller.

  However, the conventional sirocco fan has a problem that part of the air sucked from the suction port blows out from the suction port again during high load operation, and a backflow region is generated in the suction port. When this reverse flow region is generated, a large noise is generated, and the amount of air blown out from the outlet is reduced, so that the blowing efficiency of the sirocco fan is deteriorated.

Therefore, in order to provide a sirocco fan that can prevent the generation of noise without air flowing back from the suction port even during high load operation, and has good efficiency, the suction port of the casing of the sirocco fan is The fan is formed of two straight lines intersecting at substantially right angles and a circular arc substantially concentric with the rotation axis of the impeller housed in the casing, and is arranged eccentrically with respect to the rotation axis of the impeller. Since there is no air backflow area at the intake port even during high-load operation, there is no disturbance in the air flow at the intake port, so the noise during the operation of the sirocco fan is reduced and the intake air is drawn from the intake port. Since almost all of the air that has been blown out is blown out from the outlet, a sirocco fan that improves the blowing efficiency has been proposed (see, for example, Patent Document 1).
JP 2002-106497 A

  A conventional sirocco fan is formed such that a casing having a suction port that is substantially concentric with the rotation shaft of the impeller and a blower outlet covers a surface perpendicular to the outer periphery of the impeller and the rotation shaft direction. . When this impeller is operated, air is sucked from the suction port, air flows from the inside to the outside of the impeller, and the air collected by the casing is blown out from the blowout port. Experiments have shown that the suction air volume (distribution in a plane perpendicular to the suction port) at this time is large in the suction port region close to the outlet.

  Therefore, if the diameter of the suction port is enlarged as a whole in order to increase the suction air volume, the suction air flows backward in a region where the distribution of the suction air volume is small, resulting in deterioration of fan efficiency.

  Moreover, although the sirocco fan described in patent document 1 can prevent a backflow area | region even at the time of high load driving | operation, the suction inlet is not formed in the suction inlet area | region near a blower outlet with much suction | inhalation air volume. Therefore, the suction air volume cannot be increased.

  The present invention has been made to solve the above-described problems, and has realized prevention of backflow of suction air and increase in the amount of suction air, so that the suction port has the same rotational speed as that of a substantially circular shape. An object of the present invention is to provide a sirocco fan having a large blowing air volume and a low noise when compared, and an air conditioner using the same.

  A sirocco fan according to the present invention has a scroll casing formed in a spiral shape from the scroll shape starting point and forms a blowout air path along the inside of the outer peripheral wall, a fan accommodated in the scroll casing, and a scroll casing The suction port that opens in the direction of the rotation axis of the fan, and opens in the circumferential direction of the fan, and gradually increases in diameter toward the downstream from the starting point of the scroll shape between the outer periphery of the fan and the outer peripheral wall of the scroll casing. And a blower outlet located at the downstream end of the spiral blower air passage whose width in the direction expands, and at least part of the suction inlet on the blower outlet side from the straight line connecting the scroll-shaped starting point and the fan rotation axis The suction port is projected to the outlet side from the case of a circular shape.

  The sirocco fan which concerns on this invention has the effect that it can drive | operate with the large amount of blowing air at the same rotation speed, and low noise compared with a circular shaped suction inlet by the said structure.

Embodiment 1 FIG.
FIGS. 1 to 3 are diagrams showing the first embodiment. FIG. 1 is a plan view showing a sirocco fan 100. FIG. 2 is a plan view showing the sirocco fan 100. FIG. And BB cross-sectional view (b), FIG. 3 shows that when the radius of the circular portion of the suction port 21 of the sirocco fan 100 is R and the distance from the fan rotation axis 1 is r, r / R = 0.9. It is a figure which shows the suction wind speed distribution in the position.

  A sirocco fan 100 shown in FIG. 1 has a configuration in which a fan 10 (multi-blade fan) is arranged in a scroll-shaped scroll casing 20. The scroll casing 20 has a suction-side scroll wall 20b having a suction port 21 in the center and a motor-side scroll wall (not shown) with a fan motor (not shown) attached in the center in parallel, and the outer periphery of both scroll walls is not shown. It is connected with the outer wall. Between the outer periphery and the outer peripheral wall of the fan 10 is a spiral blowout air passage 24 whose radial width increases toward the downstream. The downstream end of the blowout air passage 24 is a blowout port 22. For example, when the sirocco fan 100 is used for an air conditioner, a heat exchanger or the like is disposed on the downstream side of the outlet 22. In addition, the arrow in FIG. 1 shows a blowing wind.

  A tongue 25 is disposed between the upstream end and the downstream end of the blowout air passage 24. Usually, the gap between the tongue 25 and the outer periphery of the fan 10 is small, and the ratio of the gap between the tongue 25 and the outer periphery of the fan 10 to the outer diameter of the fan 10 is about 0.03 to 0.10. Designed.

  As shown in FIG. 1, the outer peripheral wall of the scroll casing 20 is formed in a spiral shape when viewed from the suction-side scroll wall 20 b side, but the scroll-shaped starting point 20 a is arranged in the vicinity of the tongue 25. Is done. A straight line connecting the scroll starting point 20a and the fan rotation axis 1 is defined as a straight line 23 connecting the fan rotation axis 1 and the scroll starting point 20a.

  Although the suction port 21 of the scroll casing 20 is usually circular, in the present embodiment, the diameter of the region 21a near the outlet 22 of the suction port 21 where the suction air speed is large is made larger than the circular diameter. ing.

  FIG. 3 is a diagram showing a suction wind speed distribution at a position of r / R = 0.9, where R is the radius of the circular portion of the suction port 21 of the sirocco fan 100 and r is the distance from the fan rotation axis 1. is there. The angle θ shown in FIG. 3 is an angle in the counterclockwise direction (counter-rotation direction) with reference to a straight line 23 connecting the fan rotation axis 1 and the scroll-shaped start point 20a. The vertical axis of FIG. 3B indicates the maximum value of the suction wind speed as 1, and indicates the speed ratio with respect to the maximum value of the suction wind speed. The data of the speed ratio with respect to the angle θ is obtained by calculation.

  As shown in FIG. 3B, the suction air speed becomes maximum in the region where the angle θ is less than 90 degrees, that is, in the region close to the outlet 22. Further, the suction wind speed changes in a substantially sine wave shape with respect to the angle θ, and becomes minimum when the angle θ is around 270 degrees.

  Therefore, the suction air volume can be increased by making the diameter of the suction port 21 in the region 21a where the suction air speed is high larger than the circular diameter. That is, at the same rotational speed, the intake air volume increases and the noise decreases.

  The location where the diameter of the suction port 21 is made larger than the circular diameter may be on the side of the blowout port 22 from the straight line 23 connecting the fan rotation axis 1 and the scroll-shaped starting point 20a in FIG. Can be planned. In terms of the angle θ shown in FIG. 3, the diameter of the suction port 21 where 0 <angle θ <180 (unit: degree) is made larger than the circular diameter.

  By increasing the diameter of at least a part of the suction port 21 on the outlet port 22 side from the straight line 23 connecting the fan rotation axis 1 and the scroll-shaped start point 20a, the suction air volume can be increased. This is because at least a part of the suction port 21 on the side of the blow-out port 22 from the straight line 23 connecting the fan rotation axis 1 and the scroll-shaped start point 20a is stretched to the side of the blow-out port 22 than when the suction port 21 is circular. It is an example of making it come out.

  Although FIG. 1 shows a planar shape, it is as shown in FIG. 2 when viewed from the side. The BB cross section in FIG. 2 is a circular portion, and the AA cross section in FIG. 2 shows a portion in which the diameter of the suction port 21 is larger than the circular diameter. In the portion where the diameter of the suction port 21 is larger than the circular diameter, the diameter of the suction port 21 is substantially the same as the outer diameter of the fan 10. The diameter of the suction port 21 is substantially the same as the inner diameter of the fan 10.

Embodiment 2. FIG.
FIG. 4 shows the second embodiment and is a plan view of the sirocco fan 100.

  In the second embodiment, only differences from the first embodiment will be described. Therefore, the description of the same configuration as in the first embodiment is omitted.

  As shown in FIG. 4, the suction port 21 has a circular shape, but the circular center 2 of the suction port 21 is eccentric by a predetermined distance from the fan rotation axis 1 toward the blowout port 22. This is because at least a part of the suction port 21 on the side of the blow-out port 22 from the straight line 23 connecting the fan rotation axis 1 and the scroll-shaped start point 20a is stretched to the side of the blow-out port 22 than when the suction port 21 is circular. It is an example of making it come out.

  Thereby, compared with the case where the circular center 2 of the suction port 21 coincides with the fan rotation axis 1, the side opposite to the blow-out port 22 of the suction port 21 is closed, but FIG. As shown, since this region is a region where the suction air speed is low, the decrease in the suction air amount is small.

  Since the center 2 of the circular shape of the suction port 21 is decentered by a predetermined distance from the fan rotation axis 1 toward the blowout port 22 side, the suction port 21 is formed in a region where the suction air speed is high. As in the first mode, the intake air volume increases and the noise decreases at the same rotational speed.

Embodiment 3 FIG.
FIG. 5 shows the third embodiment, and is a plan view of the sirocco fan 100.

  In the third embodiment, only differences from the first embodiment will be described. Therefore, the description of the same configuration as in the first embodiment is omitted.

  The suction port 21 shown in FIG. 5 is not a circular shape but a long hole shape. More specifically, a long hole shape that connects a circular arc centered on the fan rotation axis 1 and a circular arc centered on a point 3 decentered by a predetermined distance on the outlet 22 side with respect to the fan rotation axis 1 in a substantially straight line. is there. This is because at least a part of the suction port 21 on the side of the blow-out port 22 from the straight line 23 connecting the fan rotation axis 1 and the scroll-shaped start point 20a is stretched to the side of the blow-out port 22 than when the suction port 21 is circular. It is an example of making it come out.

  The difference from the second embodiment is that the side opposite to the outlet 22 of the suction port 21 is not blocked. As a result, the suction air volume is further increased and the noise is further reduced at the same rotational speed, although slightly more than in the second embodiment.

Embodiment 4 FIG.
FIG. 6 is a diagram illustrating the fourth embodiment, and is a plan view (a) and a side view (b) of a ceiling-suspended air conditioner 200 (an example of an air conditioner).

  As shown in FIG. 6, the ceiling-suspended air conditioner 200 includes two sirocco fans 100 driven by a fan motor 50, and a heat exchanger 40 that exchanges heat between the refrigerant and air in the refrigeration cycle. . A suction grill 30 is provided at the air suction port. The number of sirocco fans 100 is not limited to two. A plurality of sirocco fans 100 such as two to four are used.

  By using the sirocco fan 10 of any one of the first to third embodiments for the sirocco fan 100 of the ceiling-suspended air conditioner 200, the ceiling-suspended air conditioner 200 having a large air volume and low noise. Can be provided.

  In addition to the ceiling-suspended air conditioner 200, for example, the sirocco fan 10 of any one of the first to third embodiments can be used for a floor-standing air conditioner.

FIG. 2 is a diagram showing the first embodiment and is a plan view showing a sirocco fan 100. FIG. It is a figure which shows Embodiment 1, and is the top view (a) which shows the sirocco fan 100, and AA sectional drawing and BB sectional drawing (b) of (a). In the figure showing the first embodiment, when the radius of the circular portion of the suction port 21 of the sirocco fan 100 is R and the distance from the fan rotation axis 1 is r, the suction at a position of r / R = 0.9. It is a figure which shows wind speed distribution. FIG. 5 shows the second embodiment and is a plan view of the sirocco fan 100. FIG. FIG. 5 shows the third embodiment and is a plan view of the sirocco fan 100. FIG. It is a figure which shows Embodiment 4, and is the top view (a) and side view (b) of the ceiling suspension type air conditioner 200.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fan rotation axis, 10 fans, 20 Scroll casing, 20a Scroll shape starting point, 20b Suction side scroll wall, 21 Suction port, 21a Area | region where suction air speed is large, 22 Air outlet, 23 Fan rotation axis 1 and scroll shape A straight line connecting the starting point 20a, 24 outlet air passage, 25 tongue, 30 suction grille, 40 heat exchanger, 50 fan motor, 100 sirocco fan, 200 ceiling-suspended air conditioner.

Claims (5)

A scroll casing which is formed in a spiral shape from the start point of the scroll shape and forms a blowout air path along the inner side of the outer peripheral wall;
A fan stored in the scroll casing;
A suction port provided in the scroll casing and opening in a rotation axis direction of the fan;
A spiral blowout air passage that opens in the circumferential direction of the fan and gradually expands in the radial direction from the start point of the scroll shape toward the downstream between the outer periphery of the fan and the outer peripheral wall of the scroll casing. A blow-off port located at the downstream end of the fan, and at least a part of the suction port on the blow-off port side from a straight line connecting the scroll-shaped starting point and the fan rotation axis, the suction port having a circular shape. A sirocco fan characterized by projecting to the outlet side.   The diameter of the suction port of the portion on the outlet side from the straight line connecting the starting point of the scroll shape and the fan rotation axis is larger than the diameter when the suction port is circular. The sirocco fan according to claim 1.   2. The sirocco fan according to claim 1, wherein the suction port has a circular shape, and a center of the circular shape is decentered from the fan rotation axis toward the blowout port by a predetermined distance.   An elongated hole shape that connects the suction port with a substantially straight line between an arc centered on the fan rotation axis and an arc centered on a point deviated from the fan rotation axis by a predetermined distance toward the outlet. The sirocco fan according to claim 1, wherein   An air conditioner using the sirocco fan according to any one of claims 1 to 4.

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