Blower

Abstract

Provided is a blower in which a cover section is easy to maintain while ensuring a sufficient amount of air. A circulator of a double reverse type is provided with: a rear impeller (24) covered by a rear cover section (30); and a front impeller (26) that is covered by the front cover section (40), the rear cover section (30) and the front cover section (40) having: a rear side surface section (31a) and a front second member (42) that constitute an annular side surface; and a rear bottom surface section (31b) and a front first member (41) provided inside the rear side surface section (31a) and the front second member (42), the rear bottom surface section (31b) and the front first member (41) having a plurality of rear first beam-shaped sections and a plurality of front first beam-shaped sections (41b) extending linearly in parallel. The rotational speed ratio per unit time of the front impeller (26) and the rear impeller (24), which is defined by formula (1), satisfies the range represented by formula (2). The rotation speed ratio = the rotation speed of the rear impeller / the rotation speed of the front impeller... (1); 1lt; and (2) the rotation speed ratio is not more than 1.2.

Description

Technical Field

[0001] The present invention relates to a blower. Background Art

[0002] Conventionally, a double-reverse type blower has been known, which includes an impeller on the suction side provided on the upstream side of the air flow path and an impeller on the discharge side provided on the downstream side of the air flow path, and the impeller on the discharge side rotates in the opposite direction to the impeller on the suction side. For example, Patent Document 1 discloses a double-reverse fan formed by combining a suction-side fan having a first impeller and a discharge-side fan having a second impeller. In this double-reverse fan, by making the rotational speed of the first impeller greater than the rotational speed of the second impeller, the air volume of the suction-side fan can be increased, and sufficient air volume during driving can be ensured.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2020 / 17132 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the blower disclosed in the above Patent Document 1, in order to ensure the air volume during driving, the shape of the beam-like portion (grille portion) of each cover portion covering each impeller is set to be radial. However, the cover portion having the beam-like portion arranged radially has the disadvantages of being difficult to clean and maintain. On the other hand, if the shape of the beam-like portion is set to a shape other than radial in order to facilitate the maintenance of the cover portion, it may not be possible to ensure sufficient air volume during driving.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a blower that can ensure sufficient air volume and whose cover portion can be easily maintained.

[0009] Means for Solving the Problems

[0010] The blower of the present invention is a double-reverse type blower, which includes: a rear impeller provided on the upstream side of the air flow path and covered by a rear cover portion; a front impeller provided on the downstream side of the air flow path and covered by a front cover portion, and at least one of the rear cover portion and the front cover portion has: a side surface portion that forms an annular side surface; a bottom surface portion provided inside the side surface portion and having a plurality of first beam-like portions extending linearly and in parallel, and when driving the blower, the rotational speed ratio of the front impeller to the rear impeller per unit time defined by the following formula (1) satisfies the range shown by the following formula (2).

[0011] Rotation speed ratio = Rotation speed of the rear impeller / Rotation speed of the front impeller... (1)

[0012] 1 < Rotation speed ratio ≤ 1.2... (2).

[0013] Advantages of the Invention

[0014] According to the present invention, a blower can be provided which can ensure sufficient air volume and whose cover part can be easily maintained. Description of the Drawings

[0015] Figure 1 is an overall perspective view of the circulator according to the embodiment as observed from the front side.

[0016] Figure 2 is a partially disassembled perspective view of the circulator according to the embodiment as observed from the front side.

[0017] Figure 3 (a) is a rear view of the rear cover part of the circulator according to the embodiment, Figure 3 (b) is a sectional view of the IIIb-IIIb section in (a).

[0018] Figure 4 (a) is a front view of the front cover part of the circulator according to the embodiment, Figure 4 (b) is a sectional view of the IVb-IVb section in (a).

[0019] Figure 5 (a) is a perspective view of the first rear part of the rear cover part of the circulator according to the embodiment as observed from the front side, Figure 5 (b) is a perspective view of the second rear part of the rear cover part as observed from the front side.

[0020] Figure 6 (a) is a perspective view of the first front part of the front cover part of the circulator according to the embodiment as observed from the front side, Figure 6 (b) is a perspective view of the second front part of the front cover part as observed from the front side.

[0021] Figure 7 is a graph showing the relationship between the efficiency of the circulator and the rotation speed ratio. Detailed Embodiments

[0022] Embodiments of the present invention will be described with reference to the drawings. As Figure 1 shown, the circulator (blower) 1 according to the present embodiment is a large circulator 1 placed on a floor surface or the like, and has: a setting part 10 provided on a setting surface; and a blower head 20 supported on the setting part 10. The blower head 20 will Figure 1The right side (the side with the rear impeller 24) shown is used as the upstream side of the air supply flow path, and Figure 1 the left side (the side with the front impeller 26) shown is used as the downstream side of the air supply flow path for air supply. Hereinafter, the upstream side of the air supply head 20 is defined as the rear side of the circulator 1, the downstream side of the air supply head 20 is defined as the front side of the circulator 1, and the right and left sides when observing the air supply head 20 from the front side are defined as the right and left sides of the circulator 1 for explanation.

[0023] First, the setting unit 10 will be described. The setting unit 10 includes: a thick plate circular plate-shaped circular plate portion 12; a pair of support arms 14 that extend upward from the left and right sides of the circular plate portion 12. A touch panel 12a for a user to operate the power on / off of the circulator 1 and the like is provided on the upper surface of the circular plate portion 12. A control unit 16 for controlling the rotational speed per unit time of the rear impeller 24 and the front impeller 26 is provided inside the circular plate portion 12. The control method of the control unit 16 for each impeller 24, 26 will be described later.

[0024] The pair of support arms 14 are each plate-shaped, and the inner surface side of the lower end portion is connected to the circular plate portion 12. An axial support portion 14a for axially supporting the air supply head 20 is provided on the inner surface side of the upper end portion of each support arm 14 (refer to Figure 2 ). The air supply head 20 can be axially supported on the axial support portion 14a of each support arm 14 so as to be rotatable about the axis in the left-right direction, and thus can swing up and down.

[0025] Next, the structure of the air supply head 20 will be described. As Figure 2 shown, the air supply head 20 includes: a cover portion mounting member 22; a rear impeller 24 that is mounted on the rear side of the cover portion mounting member 22, that is, the upstream side of the air supply flow path; a front impeller 26 that is mounted on the front side of the cover portion mounting member 22, that is, the downstream side of the air supply flow path; a rear side cover portion 30 that is mounted on the cover portion mounting member 22 so as to cover the rear impeller 24; a front side cover portion 40 that is mounted on the cover portion mounting member 22 so as to cover the front impeller 26. That is, the cover portion mounting member 22 is provided between the two impellers 24, 26.

[0026] The cover part mounting member 22 is generally in a substantially circular ring shape as a whole, and includes: an annular outer peripheral annular part 22a that constitutes its outer peripheral part; a circular circular part 22b that is provided inside the outer peripheral annular part 22a; and three beam-shaped connecting parts 22c that connect the outer peripheral annular part 22a and the circular part 22b. On the left and right sides of the outer surface side of the outer peripheral annular part 22a, there are provided shaft-supported parts 22a1 that are shaft-supported on the shaft support parts 14a of the respective support arms 14. On the rear side of the circular part 22b, there is provided a rear accommodation part 22b1 that accommodates a motor (not shown) for rotationally driving the rear impeller 24. On the front side of the circular part 22b, there is provided a front accommodation part 22b2 that accommodates a motor (not shown) for rotationally driving the front impeller 26.

[0027] The rear impeller 24 has: a substantially cylindrical rear rotating part 24a that is connected to the motor; and three rear blade parts 24b that extend outward from the outer peripheral surface of the rear rotating part 24a. The front impeller 26 has: a substantially cylindrical front rotating part 26a that is connected to the motor; and four front blade parts 26b that extend outward from the outer peripheral surface of the front rotating part 26a. In addition, the circulator 1 of the present embodiment is a double reverse type circulator 1. That is, in the circulator 1, the rear impeller 24 and the front impeller 26 are arranged with their rotation axis centers aligned in the axial direction (front-rear direction) and rotate in mutually different directions.

[0028] As Figure 2 , Figure 3 and Figure 5 shown, the rear side cover part 30 is generally in a substantially short cylindrical shape with a bottom and having a slightly reduced diameter on the rear side as a whole, and includes a rear side first member 31 and a rear side second member 32. The rear side first member 31 is generally in a grid shape composed of beam-shaped parts as a whole, and has: a rear side side surface part (side surface part) 31a that constitutes the annular side surface of the rear side cover part 30; and a rear side bottom surface part (bottom surface part) 31b that is provided inside the rear side surface part 31a and constitutes the bottom surface of the rear side cover part 30. The rear side side surface part 31a has a plurality of side beam-shaped parts 31c that extend linearly and parallelly in the front-rear direction, and the rear side bottom surface part 31b has a plurality of rear side first beam-shaped parts (first beam-shaped parts) 31d that extend linearly and parallelly in the left-right direction.

[0029] As Figure 5 (a) shown, at the front end part of the rear side side surface part 31a, that is, at the circular edge part, a plurality of rear side mounting parts 31a1 that extend inward in a claw shape are provided at intervals. The rear side cover part 30 is mounted on the cover part mounting member 22 by engaging the plurality of rear side mounting parts 31a1 with the rear side part of the outer peripheral annular part 22a of the cover part mounting member 22 respectively. In addition, on the outer peripheral part of the inner surface side (front surface side) of the rear side bottom surface part 31b, a plurality of rear side minute protrusion parts 31b1 that protrude slightly inward are provided.

[0030] As shown in Figure 5 (b), the second rear component 32 has: a rear circular ring portion 32a, which is circular; and a beam-shaped second rear beam portion (second beam portion) 32b, which extends in the vertical direction at approximately the center in the left-right direction inside the rear circular ring portion 32a. The second rear beam portion 32b is assembled and extends in a manner substantially orthogonal to the plurality of first rear beam portions 31d in a state where the first rear component 31 and the second rear component 32 are assembled. Further, at positions corresponding to the respective rear minute protrusion portions 31b1 of the first rear component 31 on the outer peripheral edge portion of the rear circular ring portion 32a, there are respectively provided rear minute notch portions 32a1 in the form of notches that engage with the rear minute protrusion portions 31b1. The first rear component 31 and the second rear component 32 are assembled by the engagement of the respective rear minute protrusion portions 31b1 and the respective rear minute notch portions 32a1.

[0031] Here, the assembly method of the first rear beam portion 31d and the second rear beam portion 32b will be described. As shown in Figure 5 (a), the respective first rear beam portions 31d are provided in a substantially plate shape at substantially equal intervals with the two plate surfaces facing in the vertical direction. At approximately the center in the left-right direction of each of the first rear beam portions 31d, there are respectively provided first rear concave portions (first concave portions) 31d1 formed in a concave shape by being recessed toward the rear side. On the other hand, as shown in Figure 5 (b), the second rear beam portion 32b is provided in a substantially plate shape with the two plate surfaces facing in the left-right direction. On the second rear beam portion 32b, a plurality of rear second concave portions (second concave portions) 32b1 formed in a concave shape by being recessed toward the front side are provided at substantially equal intervals so as to be able to be fitted into the first rear concave portions 31d1.

[0032] When the first rear component 31 and the second rear component 32 are assembled, as shown in Figure 3 (a), the respective second rear concave portions 32b1 of the second rear beam portion 32b are fitted into the first rear concave portions 31d1 of the respective first rear beam portions 31d. Thus, the second rear beam portion 32b is assembled at approximately the center in the left-right direction of each of the first rear beam portions 31d in a posture substantially orthogonal to the respective first rear beam portions 31d.

[0033] As shown in Figure 3As shown in the enlarged view E2 of (b), the first rear beam-like portion 31d and the second rear beam-like portion 32b assembled in the above-described manner are restricted from moving in the left-right direction because the first rear concave portion 31d1 interferes with both plate surfaces of the second rear beam-like portion 32b, and are restricted from moving in the up-down direction because the second rear concave portion 32b1 interferes with both plate surfaces of the first rear beam-like portion 31d, and are restricted from moving in the front-rear direction because the bottom surface of the first rear concave portion 31d1 and the bottom surface of the second rear concave portion 32b1 interfere with each other. Therefore, it is possible to prevent each first rear beam-like portion 31d from flexing in the up-down direction and the second rear beam-like portion 32b from flexing in the left-right direction, and the strength of each first rear beam-like portion 31d and the second rear beam-like portion 32b in the front-rear direction is increased.

[0034] As Figure 2 , Figure 3 and Figure 6 shown, the front cover portion 40 has a substantially short cylindrical shape with a bottom on the front side, and includes a first front component (bottom surface portion) 41 and a second front component (side surface portion) 42. The first front component 41 is a grid-like structure composed of beam-like portions, is provided inside the second front component 42, and forms the bottom surface of the front cover portion 40. The first front component 41 has a front circular ring portion 41a in the shape of a circular ring and a plurality of beam-like first front beam-like portions (first beam-like portions) 41b that linearly extend in parallel in the left-right direction inside the front circular ring portion 41a. In addition, a plurality of front minute protrusion portions 41a1 that protrude slightly rearward are provided at the outer peripheral end portion of the front circular ring portion 41a (see Figure 6 (a)).

[0035] As Figure 6 (b) shown, the second front component 42 has a substantially cylindrical shape as a whole, and has: a cylindrical portion 42a in the shape of a cylinder, which forms the annular side surface of the front cover portion 40; and a beam-like second front beam-like portion (second beam-like portion) 42b, which extends in the up-down direction at approximately the center in the left-right direction within the opening on the front side of the cylindrical portion 42a. The second front beam-like portion 42b is assembled and extends in a manner substantially orthogonal to the plurality of first front beam-like portions 41b in a state where the first front component 41 and the second front component 42 are assembled (see the enlarged view E1 of Figure 2 ).

[0036] In addition, as Figure 4As shown in (b), at the rear end portion of the cylindrical portion 42a, i.e., the circular edge portion, a plurality of front side mounting portions 42a1 extending claw-like inward are provided at intervals. The front side cover portion 40 is mounted on the cover portion mounting member 22 by engaging with the front side portion of the outer peripheral annular portion 22a of the cover portion mounting member 22 through the plurality of front side mounting portions 42a1 respectively. In addition, at the outer peripheral edge portion on the front end side of the cylindrical portion 42a, at positions corresponding to the respective front side minute protrusion portions 41a1 of the front side first member 41, notch-shaped front side minute notch portions 42a2 that engage with the front side minute protrusion portions 41a1 are respectively provided. By engaging the respective front side minute protrusion portions 41a1 with the respective front side minute notch portions 42a2, the front side first member 41 and the front side second member 42 are assembled.

[0037] Here, the assembly method of the front side first beam portion 41b and the front side second beam portion 42b will be described. As Figure 6 shown in (a), the respective front side first beam portions 41b are arranged in a substantially plate shape at substantially equal intervals with the two plate surfaces facing the up and down directions. At substantially the central portion in the left-right direction of each front side first beam portion 41b, front side first concave portions (first concave portions) 41b1 that are recessed in the frontward direction are respectively provided in a concave shape. On the other hand, as Figure 6 shown in (b), the front side second beam portion 42b is arranged in a substantially plate shape with the two plate surfaces facing the left and right directions. A plurality of front side second concave portions (second concave portions) 42b1 that are recessed in the rearward direction are provided at substantially equal intervals on the front side second beam portion 42b so as to be able to engage with the front side first concave portions 41b1.

[0038] When assembling the front side first member 41 and the front side second member 42, as Figure 4 shown in (a), the respective front side second concave portions 42b1 of the front side second beam portion 42b are engaged with the front side first concave portions 41b1 of the respective front side first beam portions 41b. Thus, the front side second beam portion 42b is assembled at substantially the central portion in the left-right direction of each front side first beam portion 41b in a posture substantially orthogonal to each front side first beam portion 41b.

[0039] As Figure 4As shown in the enlarged view E3 of (b), the first front beam portion 41b and the second front beam portion 42b assembled in the above-described manner are restricted from moving in the left-right direction because the first front concave portion 41b1 interferes with both plate surfaces of the second front beam portion 42b, and are restricted from moving in the up-down direction because the second front concave portion 42b1 interferes with both plate surfaces of the first front beam portion 41b, and are restricted from moving in the front-back direction because the bottom surface of the first front concave portion 41b1 and the bottom surface of the second front concave portion 42b interfere with each other. Therefore, it is possible to prevent each first front beam portion 41b from flexing in the up-down direction and the second front beam portion 42b from flexing in the left-right direction, and moreover, the strength of each first front beam portion 41b and the second front beam portion 42b with respect to the front-back direction is increased.

[0040] As described above, in the circulator 1 of the present embodiment, the rear cover portion 30 and the front cover portion have the structures as described above. Thus, when cleaning the rear cover portion 30 and the front cover portion 40, it is possible to clean along the rear first beam portion 31d and the front first beam portion 41b that linearly extend in parallel, using a cleaning brush or the like. Therefore, it is possible to easily clean the rear cover portion 30 and the front cover portion 40. That is, the circulator 1 that can easily achieve the maintenance of the cover portion.

[0041] Next, a control method for the rear impeller 24 and the front impeller 26 in the control unit 16 will be described. In the circulator 1 of the present embodiment, when the circulator 1 is driven, the control unit 16 controls the rear impeller 24 and the front impeller 26 to satisfy the range shown in the following formula (2) when defining the rotation speed ratio per unit time of the rear impeller 24 and the front impeller 26 by the following formula (1).

[0042] Rotation speed ratio = Rotation speed of the rear impeller 24 / Rotation speed of the front impeller 26... (1)

[0043] 1 < Rotation speed ratio ≤ 1.2 ··· (2)

[0044] As an example, when the control unit 16 controls the circulator 1 to drive, the rotation speed of the front impeller 26 per minute is set to 2200 revolutions, and the rotation speed of the rear impeller per minute is set to 2500 revolutions. In this case, the rotation speed ratio defined by the above formula (1) is 1.14.

[0045] Here, assuming that the rotation speeds (hereinafter simply referred to as "rotation speeds") per unit time of the rear impeller 24 and the front impeller 26 are the same, then as the rotation speed increases, the wind speed at a position away from the circulator 1 (for example, a position one meter away from the circulator 1. Hereinafter referred to as the "measurement position") increases, but the consumption current consumed by the drive of the circulator 1 increases. If the consumption current becomes a certain value or more, it becomes a circulator that cannot be used in a general household with limited power supply.

[0046] In addition, in a double reverse blower such as the circulator 1 of the present embodiment, even if the rotational speed of the rear impeller 24 is not changed and only the rotational speed of the front impeller 26 is increased, the wind speed at the measurement position hardly increases. By making the rotational speed of the rear impeller 24 higher than that of the front impeller 26, the wind speed at the measurement position increases. However, if the difference between the rotational speed of the rear impeller 24 and the rotational speed of the front impeller 26 becomes large, since the wind does not spread, the advantage of double reverse that can send air to a distance is lacking, and the efficiency (wind speed at the measurement position / consumption current) decreases. Especially when it is far from the measurement position, the influence is significant.

[0047] Therefore, in the circulator 1 of the present embodiment, the control unit 16 increases the rotational speed of the rear impeller 24 to be higher than that of the front impeller 26, and at the same time, controls the rotational speed ratio of the rear impeller 24 and the front impeller 26 to be 1 < rotational speed ratio ≤ 1.2, so that it is possible to increase the wind speed at the measurement position while suppressing the increase in consumption current. Therefore, it is possible to achieve a circulator 1 with good efficiency while ensuring sufficient air volume.

[0048] As described above, the circulator 1 according to the present embodiment is a double reverse type circulator 1, which has: a rear impeller 24 provided on the upstream side of the air flow path and covered by the rear cover portion 30; a front impeller 26 provided on the downstream side of the air flow path and covered by the front cover portion 40. The rear cover portion 30 and the front cover portion 40 have: a rear side surface portion 31a and a front second member 42 that form an annular side surface; a rear bottom surface portion 31b and a front first member 41 provided inside the rear side surface portion 31a and the front second member 42, and having a plurality of rear first beam-shaped portions 31d and a plurality of front first beam-shaped portions 41b that linearly extend in parallel. The rotational speed ratio per unit time of the front impeller 26 and the rear impeller 24 defined by the following formula (1) when driving the circulator 1 satisfies the range shown in the following formula (2).

[0049] Rotational speed ratio = rotational speed of rear impeller / rotational speed of front impeller ··· (1)

[0050] 1 < rotational speed ratio ≤ 1.2 ··· (2)

[0051] According to the circulator 1 of this embodiment configured in this way, when cleaning the rear cover portion 30 and the front cover portion 40, it is possible to easily perform cleaning along each rear first beam portion 31d and each front first beam portion 41b using a cleaning brush or the like. Therefore, it is possible to easily perform maintenance of the rear cover portion 30 and the front cover portion 40. In addition, in the circulator 1 of this embodiment which is a double reverse type, by controlling the speed ratio of the rotational speed of the rear impeller 24 and the rotational speed of the front impeller 26 to satisfy the range shown in the above formula (2), it is possible to increase the wind speed at a constant position while suppressing an increase in power consumption current, and it is possible to improve the efficiency (wind speed at the measurement position / power consumption current). In this way, in this embodiment, it is possible to realize a circulator 1 that can easily maintain the cover portion while ensuring sufficient air volume.

[0052] In addition, in the circulator 1 of this embodiment, the rotational speed per minute of the rear impeller 24 when the circulator 1 is driven is 2500 revolutions or less, and the speed ratio is 1.1 or more. When the rotational speed per minute of the rear impeller 24 is greater than 2500 revolutions, the power consumption current becomes large, so the efficiency of the circulator 1 is likely to decrease. In addition, when the speed ratio is less than 1.1, the wind speed at the measurement position becomes small, and the efficiency of the circulator 1 is likely to decrease. Therefore, by setting the rear impeller 24 and the front impeller 26 to the above control method, it is possible to further improve the efficiency of the circulator 1.

[0053] In addition, in the circulator 1 of this embodiment, the rear cover portion 30 and the front cover portion 40 are provided inside the rear side surface portion 31a and the front second member 42, and have a rear second beam portion 32b and a front second beam portion 42b that extend substantially orthogonally to the plurality of rear first beam portions 31d and the plurality of front first beam portions 41b. According to this structure, since each rear first beam portion 31d is strengthened by the rear second beam portion 32b, it is possible to prevent each rear first beam portion 31d from flexing when cleaning the rear cover portion 30 or the like. Each front first beam portion 41b is strengthened by the front second beam portion 42b, so it is possible to prevent each front first beam portion 41b from flexing when cleaning the front cover portion 40 or the like.

[0054] In addition, in the circulator 1 of the present embodiment, the plurality of rear first beam portions 31d and the plurality of front first beam portions 41b have rear first concave portions 31d1 and front first concave portions 41b1 provided in a concave shape, and the rear second beam portions 32b and the front second beam portions 42b have a plurality of rear second concave portions 32b1 and a plurality of front second concave portions 42b1 provided in a concave shape so as to be able to engage with the rear first concave portions 31d1 and the front first concave portions 41b1. By engaging the rear first concave portions 31d1 of the plurality of rear first beam portions 31d and the front first concave portions 41b1 of the plurality of front first beam portions 41b with the plurality of rear second concave portions 32b1 and the plurality of front second concave portions 42b1 in a substantially orthogonal manner respectively, the rear first beam portion 31d and the rear second beam portion 32b are assembled, and the front first beam portion 41b and the front second beam portion 42b are assembled.

[0055] According to this structure, the rear first concave portions 31d1 are respectively engaged with the plurality of rear second concave portions 32b1 in a substantially orthogonal manner, thereby restricting the movement of both in two substantially orthogonal directions. The front first concave portions 41b1 are respectively engaged with the plurality of front second concave portions 42b1 in a substantially orthogonal manner, thereby restricting the movement of both in two substantially orthogonal directions. Therefore, it is possible to improve the strength of the plurality of rear first beam portions 31d and the rear second beam portions 32b, and the strength of the plurality of front first beam portions 41b and the front second beam portions 42b respectively.

[0056] In addition, the embodiments described above are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope or gist of the invention, and are included in the invention described in the claims and its equivalents.

[0057]

Embodiment

[0058] Hereinafter, the present invention will be described in more detail by way of examples, but the technical scope of the present invention is not limited thereto. In this embodiment, a circulator having the same structure as the circulator 1 described in the above embodiment is used, and while controlling the rotational speed of the rear impeller and the rotational speed of the front impeller, the efficiency is calculated based on the wind speed and the consumption current at the measurement position, and the rotational speed ratio for achieving the optimum efficiency is derived. In addition, in the circulator used in this embodiment, the axial dimension (front-rear dimension, for example, 30 mm) of the front impeller is set to be smaller than the axial dimension (for example, 40 mm) of the rear impeller, so that even if the rotational speed of the front impeller is smaller than the rotational speed of the rear impeller, the wind speed is difficult to decrease.

[0059] For the rear impeller, within the range of 2400 rpm to 2650 rpm per minute, the rotational speed is changed in units of 50 revolutions while measuring the wind speed. For the front impeller, the wind speed is measured while changing the rotational speed, and the rotational speed per minute is within the range of 2000 rpm to 2650 rpm, and the speed ratio (rotational speed of the rear impeller / rotational speed of the front impeller) is within the range of 1.0 to 1.4.

[0060] In the measurement of the wind speed, the position 1 m away from the circulator on the front side of the circulator is used as the measurement position. In the measurement of the wind speed at the measurement position, AIR FLOW (model: LCA 501) manufactured by TSI Incorporated is used. In the measurement of the current consumption, a fanless wide-range DC stabilized power supply (model: PFR-100L 50) manufactured by Texio Technology Co., Ltd. is used. The wind speed unit is m / s, and the current consumption unit is A. Based on the measured wind speed and current consumption, the efficiency (wind speed / current consumption) is calculated.

[0061] In Figure 7 a graph showing the measurement results plotted as a scatter diagram is shown. Additionally, in Figure 7 the horizontal axis represents the speed ratio and the vertical axis represents the efficiency. Additionally, Figure 7 the curve indicated by the dashed line in

[0062] As Figure 7 shown, it can be seen that within the range of 2400 rpm to 2650 rpm of the rotational speed of the rear impeller, regardless of which speed ratio exceeds 1.2, the efficiency tends to decrease. From this, it can be known that by making the speed ratio of the rear impeller and the front impeller greater than 1 and within the range of 1.2 or less, a circulator with good efficiency can be achieved.

[0063] Additionally, as Figure 7 shown, within the range where the rotational speed of the rear impeller is 2500 rpm or less (2500 rpm, 2450 rpm, 2400 rpm) and the speed ratio is 1.1 or more and 1.2 or less, the efficiency is 3.0 or more in all the plotted values, and high efficiency can be achieved.

[0064] Symbol Explanation

[0065] 1... Circulator 10... Setting part

[0066] 12... Circular plate part 12a... Touch panel

[0067] 14... Support arm 14a... Shaft support part

[0068] 16... Control part 20... Air outlet

[0069] 22…Cover mounting part 22a…Outer peripheral ring part

[0070] 22a1…Axially supported part 22b…Circular part

[0071] 22b1…Rear housing part 22b2…Front housing part

[0072] 22c…Beam-shaped connecting part 24…Rear impeller

[0073] 24a…Rear rotating part 24b…Rear blade part

[0074] 26…Front impeller 26a…Front rotating part

[0075] 26b…Front blade part 30…Rear side cover

[0076] 31…Rear side first part 31a…Rear side side face part

[0077] 31a1…Rear side mounting part 31b…Rear side bottom face part

[0078] 31b1…Rear side micro projection part 31c…Side beam-shaped part

[0079] 31d…Rear side first beam-shaped part 31d1…Rear side first concave part

[0080] 32…Rear side second part 32a…Rear side circular ring part

[0081] 32a1…Rear side micro incision part 32b…Rear side second beam-shaped part

[0082] 32b1…Rear side second concave part 40…Front side cover

[0083] 41…Front side first part 41a…Front side circular ring part

[0084] 41a1…Front side micro projection part 41b…Front side first beam-shaped part

[0085] 41b1…Front side first concave part 42…Front side second part

[0086] 42a…Cylindrical part 42a1…Front side mounting part

[0087] 42a2…Front side micro incision part 42b…Front side second beam-shaped part

[0088] 42b1…Front side second concave part

Claims

1. A blower, which is a double-reverse blower, having: a rear impeller disposed on the upstream side of the air flow path and covered by a rear shroud portion; a front impeller disposed on the downstream side of the air flow path and covered by a front shroud portion, wherein, at least one of the rear shroud portion and the front shroud portion has: a side surface portion constituting an annular side surface; a bottom surface portion disposed inside the side surface portion and having a plurality of first beam-shaped portions extending linearly and in parallel, when driving the blower, the rotational speed ratio per unit time of the front impeller and the rear impeller defined by the following formula (1) satisfies the range shown in the following formula (2), Rotational speed ratio = Rotational speed of the rear impeller / Rotational speed of the front impeller... (1) 1 < Rotational speed ratio ≤ 1.2... (2).

2. The blower according to claim 1, wherein, the rotational speed of the rear impeller per minute during the driving of the blower is 2500 revolutions or less, the rotational speed ratio is 1.1 or more.

3. The blower according to claim 1 or 2, wherein, at least one of the rear shroud portion and the front shroud portion has a second beam-shaped portion disposed inside the side surface portion and extending substantially orthogonally to the plurality of first beam-shaped portions.

4. The blower according to claim 3, wherein, the plurality of first beam-shaped portions have first concave portions provided in a concave shape, the second beam-shaped portion has a plurality of second concave portions provided in a concave shape and capable of fitting into the first concave portions, the first concave portions of the plurality of first beam-shaped portions are respectively fitted with the plurality of second concave portions in a substantially orthogonal manner, thereby assembling the first beam-shaped portion and the second beam-shaped portion.

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