Cylindrical blower

Abstract

To reduce noise in a cylindrical air blower with which diffusion of an airflow leaving an air blow-out port is reduced.SOLUTION: A cylindrical air blower includes a cylinder 110 provided with an air suction port 120 in a rear end thereof and an air blow-out port 130 in a front end thereof, a fan 152 provided within the cylinder 110, and an arm 170 attached to the cylinder such that the cylinder can rotate. When a direction orthogonal to a front-back direction and a left-right direction of the cylinder 110 is defined as a vertical direction, a through hole for reducing noise is provided below the cylinder 110.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cylindrical blower.

Background Art

[0002] Cylindrical blowers are used, for example, as blowers in tunnel blowers and blower application products such as dryers and air cleaners, where they create an air flow in a limited area with little diffusion of the air flow.

[0003] Patent Document 1 discloses an air flow generating device with a housing having an air inlet at its first end and an air outlet at its second end, and having a rotary fan and air guiding vanes (rectifier plates) therebetween, with little diffusion of the air flow. The rotary fan has blades, and it is said that noise can be reduced by changing the number of blades and the number of vanes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventor of the present invention is developing a blower that can be used in an office or other relatively quiet environment and can blow air to a specific location such as a place where people are present. At that time, since the housing of the blower is exposed to change the direction, noise may be a concern compared to a ceiling - embedded blower. Therefore, when developing a cylindrical blower with little diffusion of the air flow, the inventor has set the development task of reducing noise.

Means for Solving the Problems

[0006] The present invention provides a cylinder provided with an air inlet at the rear end and an air outlet at the front end, and A fan is provided inside the aforementioned cylinder, The cylinder is provided with an arm attached to it so that it can rotate, The direction perpendicular to the front-to-back and left-to-right directions of the aforementioned cylinder is defined as the up-and-down direction, and the lower side of the cylinder is provided with a through hole to reduce noise. The upper side of the cylinder does not have the through hole. , It is a cylindrical blower.

[0007] In the present invention, the through-holes are elongated vertically in the front-to-back direction and may be provided in multiple locations. [Effects of the Invention]

[0008] In this invention, noise can be reduced by providing an opening in the cylindrical part of the cylindrical blower, specifically in the region surrounding the fan. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of the cylindrical blower of Embodiment 1 [Figure 2] Axial cross-sectional view of the cylindrical blower of Embodiment 1 [Figure 3] Simulation diagram of the airflow of the cylindrical blower in Embodiment 1 [Figure 4] Diagram showing the frequency and level of sound generated by the cylindrical blower of Embodiment 1. [Figure 5] Perspective view of a cylindrical blower according to a modified embodiment of Embodiment 1 [Figure 6] Airflow simulation diagram for examining the cylindrical blower of Embodiment 2 [Figure 7] Perspective view of the cylindrical blower of Embodiment 2 [Figure 8] Perspective view of the cylindrical blower of Embodiment 3 [Modes for carrying out the invention]

[0010] <Embodiment 1> <Structure> The cylindrical blower 100 of this embodiment can be attached to a wiring duct 180 and the direction of the airflow can be changed as needed.

[0011] FIG. 1 is a perspective view of the cylindrical blower 100B. In the following description, terms such as the front F direction, the rear B direction, the upper U direction, and the lower D direction are used based on the axis AX in FIG. 1. Also, the direction orthogonal to the axis AX and the vertical direction may be described as left and right.

[0012] In FIG. 1, the cylindrical blower 100B includes a cylinder 110 provided with an air inlet 120 at the rear end and an air outlet 130 at the front end. The cylinder 110 is divided into a rear cylinder portion 111 and a front cylinder portion 112B. An arm 170 rotatably attached to the side surface of the rear cylinder portion 111 and an attachment portion 178 attached to the wiring duct 180 are provided at the other end of the arm 170.

[0013] As the front cylinder portion, a front cylinder portion 112A without a through hole on the side surface, a front cylinder portion 112B provided with a through hole 115B which is an opening in the lower half of the side surface, and a front cylinder portion 112C provided with a through hole 115C which is an opening on the entire circumference of the side surface were prototyped. In FIG. 1, the front cylinder portion 112B is shown as a representative. The cylindrical blowers using the front cylinder portions 112A, 112B, and 112C are respectively referred to as cylindrical blowers 100A, 100B, and 100C, and are collectively referred to as the front cylinder portion 112 and the cylindrical blower 100. The through holes 115B and 115C are also collectively referred to as the through hole 115.

[0014] The through hole 115 is vertically long in the front-rear direction and a plurality of them are provided. This is because a portion corresponding to a "pillar" for providing the mechanical strength of the front cylinder portion 112 is required between the through holes, and the size of the through hole is made such that a finger cannot enter to ensure safety.

[0015] The axis AX, which is the direction of the cylindrical blower 100, can be rotated horizontally by the rotation of the arm 170 in the Φ direction with respect to the attachment portion 178. Also, the direction can be changed to an appropriate direction from downward to upward by the rotation of the rear cylinder portion 111 in the θ direction with respect to the arm 170.

[0016] The cylindrical blower 100 can be turned ON / OFF and its airflow controlled by communication using radio waves or infrared rays from a control device 190, which is a tablet, smartphone, PC, or remote control.

[0017] Figure 2(a) is a cross-sectional view of the cylindrical blower 100B including its axis AX. Inside the cylindrical blower 100B are a power supply 140, a motor 151, a fan 152 rotated by the motor 151, and a rectifier plate 160. As the fan 152 rotates, an airflow W passes through the space between the power supply 140 and the rear cylindrical section 111, and the airflow is released in the direction F.

[0018] Figure 2(b) shows the cylindrical blower 100B viewed from the F side (front side) of the air outlet 130. It can be seen that there are eight rectifier plates 160 and three fans 152.

[0019] The cylindrical blower 100B has a length of 190 mm from the air intake 120 to the air outlet 130, a length of 65 mm for the rear cylinder 111, a length of 125 mm for the front cylinder 112, and an outer diameter of 85 mm for the air intake 120 and air outlet 130. However, cylindrical blowers of different sizes are also under consideration.

[0020] <Fan and through hole> Referring again to Figure 2(a), let S1 be the point obtained by projecting a plane perpendicular to the axis AX, including the front end 152F of the fan, onto the front cylinder portion 112, and let S2 be the point obtained by projecting a plane perpendicular to the axis AX, including the rear end 152B of the fan, onto the front cylinder portion 112. Let L be the distance between S1 and S2. f This is shown as follows. Let S3 be the midpoint between S1 and S2. Also, let L be the range in which the through hole 115 is provided. h In the front cylinder portion 112B, the range L corresponding to the side of the fan 152 is defined as follows. f The range L of the through hole 115 includes h A through hole is provided. The length of the through hole is L. h The diameter is 45 mm, the width of the through-holes is 5.2 mm, the distance between the through-holes is 2.6 mm, and the number of through-holes is 16.

[0021] <Airflow Simulation> Figure 3(a) shows the simulation results of the internal airflow of a cylindrical blower 100A using a front cylinder section 112A without through holes, and Figure 3(b) shows the simulation results of a cylindrical blower 100C using a front cylinder section 112C having through holes 115C all around.

[0022] Figures 3(a) and (b) show the airflow width DA and DC at the air outlet 130, respectively. The fact that width DC is narrower than width DA indicates that the through-hole 115C is affecting the airflow width. In the original figure, the color changes from blue (weak) to green (medium) to yellow (slightly strong) to red (strong) as the wind speed changes from weak to strong. However, the arrows indicating the airflow DA are dark gray (original green (medium)) and the arrows indicating the airflow DC are light gray (original yellow (slightly strong)), which is consistent with the result that a smaller airflow width corresponds to a stronger airflow. From this, it can be assumed that by providing the through-hole 115C, the airflow width is narrowed, the directivity of the airflow is strengthened, and the diffusion of the airflow is reduced.

[0023] Furthermore, the airflow in front of the fan 152, for example point P in Figure 3(a), is dark gray (originally red (strong)), and the airflow in the airflow behind the fan 152, for example point Q in Figure 3(a), is medium (originally green (medium)). The airflow in front of and behind the fan 152 in Figure 3(b) is almost the same. On the other hand, in Figure 3(b), the airflow exiting from the through-hole 115C and the airflow entering the through-hole are not depicted, indicating that the air intake and discharge at the through-hole 115C are so small that they are not shown, and that the through-hole 115C does not substantially function as an "air intake" or "air outlet."

[0024] Comparing Figures 3(a) and 3(b), a difference is observed, particularly near the front end 152F of the fan, where the airflow width is wider in Figure 3(a) and narrower in Figure 3(b). Therefore, we believe it would be best to position the through-hole so that it includes at least point S1, which is the projection of the front end 152F of the fan onto the cylinder.

[0025] Regarding the effect of the through-hole on airflow, the inventors have assumed the following model. For example, at point T near the front cylinder portion 112 in Figure 3(a), the pressure is high when the fan is at the rear and low when the fan is at the front. As the fan rotates, the high and low pressure states alternate, causing pressure fluctuations. Here, if there is a through-hole 115 in the front cylinder portion 112, instantaneous air can enter and exit through the through-hole 115, which is estimated to reduce pressure fluctuations. If we consider these pressure fluctuations to be one of the causes of noise, then it can be explained that noise can be reduced by making a through-hole in the cylinder next to the fan. Before the experiment, it was thought that the through-hole would become a passage for sound, thus causing noise to escape and increasing noise levels. In reality, even if sound were to be emitted from the through-hole, the object to which the air is blown is usually in front (direction F), and people are often also in front of it. However, the sound emitted from the through-hole mainly spreads in directions such as D. Therefore, the cylindrical blower 100A or 100B, which is a ceiling-mounted blower, can be said to have a structure that is suitable for noise reduction when installed on the ceiling in stores, offices, and other similar places.

[0026] <Noise measurement results> For cylindrical blowers 100A, 100B, and 100C, the noise measurement results when the same power was applied were 38.9 dB, 36.6 dB, and 36.1 dB, respectively. The noise (dB) is the SPL value (Sound Pressure Level) using A-weighting, which corresponds to the frequency weighting of human hearing.

[0027] The noise mentioned above represents the overall noise level, but Figure 4 shows the noise spectrum measurements broken down by sound frequency. The vertical axis represents the SPL for each frequency, the horizontal axis represents the sound frequency f (Hz), and lines 100A, 100B, and 100C represent the noise levels of cylindrical blowers 100A, 100B, and 100C at different frequencies, respectively. In Figure 4, the trend may differ depending on the frequency, but at least in the frequency range enclosed by the rectangle, the SPL relationship is 100A > 100B > 100C, confirming that 100C has a noise reduction effect.

[0028] From the standpoint of noise reduction, a cylindrical blower 100C with through holes around the entire circumference of the front cylinder 112 is suitable. However, if the through holes are provided on the U-side (upper side) of the front cylinder 112, there is another problem: dust can enter. Taking this into consideration, a cylindrical blower 100B with through holes on the lower side of the front cylinder 112 is preferable.

[0029] If the through-hole 115 is extended beyond the side of the fan in the front cylindrical section 112, the directivity of the airflow, which is a characteristic of cylindrical blowers, may be impaired, and there is a concern that the flow will diffuse. Therefore, it is best not to make the through-hole too long in the forward direction, and the length added in front of point S1, which is the projection of the front end 152F of the fan, should be L. f I think the following is good.

[0030] <Rectifier plate> The rectifier plates 160 shown in Figures 2(a) and (b) have the function of rectifying the airflow and also prevent fingers from touching the fan 152. Although eight rectifier plates 160 are shown facing outward from the axis AX, four, six, eight, or twelve plates may also be used.

[0031] <Power supply> A power supply 140 is installed between the air intake 120 and the fan 152 in the cylinder 110. The power supply 140 has a cylindrical shape and is miniaturized to ensure an air passage between the power supply 140 and the inner surface of the cylinder 110. The power supply 140 converts the AC commercial power input from the wiring duct into DC.

[0032] Furthermore, the power supply may be located not inside the cylinder 110, but, for example, at the mounting portion 178. This reduces air resistance inside the cylinder and increases airflow. In addition, the rear cylinder portion 111 can be eliminated.

[0033] <Operation Control> The control device 190 allows for scheduled operation of the cylindrical blower. Scheduled operation allows the blower to be turned ON at opening time or the start of work hours, and OFF at closing time or the end of work hours, enabling the airflow to be adjusted to high or low depending on the time of day. Furthermore, sensor-linked operation is possible using sensors that can communicate with the control device 190, allowing the airflow to be controlled according to temperature, humidity, and human density measured by the sensors.

[0034] <Modified example 1 of cylindrical blower 100C> While the cylindrical blower 100C, which has through holes 115C around the entire circumference of the front cylinder, is excellent in terms of noise reduction, it had the problem of dust entering the interior. Therefore, in the cylindrical blower 100D, which is Modification 1 shown in a perspective view in Figure 5, a plate 117, which acts as a roof, is installed above the through holes 115C with a small gap in between. As a result, even though through holes 115C are provided around the entire circumference, dust is blocked by the plate 117 and is less likely to enter the inside of the cylinder. The plate 117 may also be provided around the entire circumference of the front cylinder 112C.

[0035] <Modified example 2 of cylindrical blower 100C> In the cylindrical blower 100E (not shown) of Modification 2, through holes 115C are provided around the entire circumference, and a thin film is attached to the inner or outer surface of at least the upper through holes 115C to seal them. This film is, for example, about 0.2 mm, 0.1 mm, or 0.05 mm thick and is made of a flexible material, so it can vibrate in response to fluctuations in air pressure caused by fan rotation. This makes it possible to achieve both dust prevention and noise reduction. Since openings or through holes covered with such vibrating films in response to fluctuations in air pressure have the same function as ordinary openings or through holes from the standpoint of noise reduction, the same names (openings / through holes) will be used, and the explanation "openings / through holes capable of transmitting instantaneous pressure fluctuations inside the cylinder to the outside of the cylinder" will be added as needed.

[0036] <Embodiment 2> <Structure> The cylindrical blower 100F of Embodiment 2 has through holes 114B in the lower half around the rear cylindrical portion 111B, in addition to the through holes 115B near the fan. Other aspects are the same as 100B of Embodiment 1.

[0037] As a preliminary step to this embodiment, the effect of the through-hole 114C was investigated when a through-hole 114C is provided around the entire circumference of the rear cylinder portion 111 in 100A, which does not have a through-hole near the fan. The results of the airflow simulation in that case are shown in Figure 6. The width DE of the airflow at the air outlet 130 is slightly increased compared to DA in Figure 3(a).

[0038] Based on the above findings, a prototype of cylindrical blower 100F was manufactured. A perspective view of this prototype is shown in Figure 7. Compared to cylindrical blower 100B, cylindrical blower 100F did not achieve a significant further noise reduction, but it was found that the airflow was slightly increased. In other words, when compared at the same airflow, the noise is slightly reduced.

[0039] Based on these results, it is suitable to use through-hole 114 (through-hole 114C or through-hole 114B considering dust prevention) together with through-hole 115 (through-hole 115C or through-hole 115B considering dust prevention). Alternatively, through-hole 114 may be provided as a continuous elongated hole with through-hole 115.

[0040] <Embodiment 3> <Structure> The cylindrical blower 100G of Embodiment 3 has an opening 115G near the fan provided in the front cylindrical section 112G.

[0041] In the front cylinder section 112G shown in Figure 8, an opening 115G is provided in the lower half of the side surface near the fan 152. A guard wire 116 is provided to prevent fingers from entering the opening 115G.

[0042] In this embodiment, the area of ​​the opening can be made larger compared to the through-hole shape of the opening used in Embodiments 1 and 2, thereby increasing the noise reduction effect.

[0043] Although the opening 115G is provided in the lower half of the front cylinder portion 112G, it may be provided around the entire circumference. In that case, the front cylinder may be supported by a shaft provided on the motor side, for example, or by a guard wire 116.

[0044] <Variation> Although embodiments of the cylindrical blower according to the present invention have been described above, it is also possible to modify the exemplified cylindrical blower as follows, for example, and it goes without saying that the present invention is not limited to the cylindrical blower as shown in the above-described embodiments.

[0045] Although each embodiment has been described as a simple cylindrical blower, the present invention can be applied to blower-based products such as dryers, which are cylindrical blowers that blow warm air, air purifiers that incorporate filters for air purification or devices for disinfection, sterilization, and virus inactivation, and large blowers used for ventilating tunnels, etc. It may also be used, for example, as a blower in the front part of a bladeless fan.

[0046] The term "cylindrical" is not limited to a cylindrical shape; it may also refer to a curved cylindrical shape, such as that described in Prior Art 1. The cylinder may be linear with respect to the axis AX, as in each embodiment, or it may be curved.

[0047] In each embodiment, the front cylinder that directs the fan and airflow and the rear cylinder that houses the power supply are separate components, but they may be a single integrated component. Also, if the front and rear cylinders are separated, the fan may be placed inside the rear cylinder. Furthermore, the portion of the front cylinder near the fan and the portion further forward may be separate components. The rear cylinder that houses the power supply may be omitted.

[0048] In each embodiment, the arm is attached to the side of the rear cylinder, but the attachment position of the arm is not limited to this; it may also be attached to the front cylinder or to the air intake side.

[0049] As a blower with a shape intermediate between a fan and a cylindrical blower, there are fans and circulators, for example, that have a protective frame surrounding the fan, but if it is necessary to clarify the difference between these and the present invention, it is particularly preferable that the length of the cylinder (sum of the length of the front cylinder and the length of the rear cylinder) is 1 or more times, preferably 1.3 or more times, and more preferably 1.5 or more times longer than the outer diameter of the air intake. Furthermore, it is preferable that the opening (through hole) is provided to include a length from point S1 projected from the front end 152F of the fan to point S2 projected from the rear end 152B of the fan, preferably to include a length from S1 to an intermediate point S3, and preferably to include S1. It is preferable that a rectifier plate is provided in front of the fan inside the cylinder. At least length L is provided on the front side of the front end of the fan of the cylinder. f or greater than or the length L h It is preferable to have a region without the above-mentioned openings (openings of a size that have little effect on airflow may be provided).

[0050] In the cylindrical blower 100B, the "lower side" where the through hole is provided may be the lower side when the circumference of the front cylinder is divided into two parts, "upper" and "lower". Also, when the circumference of the front cylinder is divided into four parts, "upper," "lower," "right side," and "left side," the lower side may include the right side and left side, include them partially, or not include them at all.

[0051] Although a cylindrical blower mounted on a wiring duct rail has been described in each embodiment, the cylindrical blower of the present invention may be installed directly on the ceiling without using a wiring duct rail. Furthermore, it does not have to be a ceiling-mounted type, and it may be used without fixed installation.

[0052] The through hole is preferably elongated in the axial direction AX, and the ratio of the axial length to the width is preferably 3 to 20 times, and more preferably 5 to 10 times.

[0053] Furthermore, the embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of the present invention is not construed solely by the embodiments described above, but is defined based on the claims. This also includes all modifications within the meaning and scope of the equivalents of the claims. [Explanation of symbols]

[0054] 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G cylindrical blower 110 tubes 111 Rear cylinder part 112, 112A, 112B, 112C, 112G Front cylinder part 114, 114B, 114C through hole 115, 115B, 115C through hole 115G opening 116 Guard Wire 117 board 120 Air intake 130 Air outlet 140 Power supply 151 Motor 152 fans 152F Fan front end 152B Fan rear end 160 Rectifier plate 170 Arm 178 Mounting part 180 Wiring duct 190 Control device

Claims

1. A cylinder with an air intake at the rear end and an air outlet at the front end, A fan is provided inside the aforementioned cylinder, The cylinder is provided with an arm attached to it so that it can rotate, The direction perpendicular to the front-to-back and left-to-right directions of the aforementioned cylinder is defined as the up-and-down direction. The lower side of the cylinder is provided with a through hole to reduce noise, and the upper side of the cylinder is not provided with the aforementioned through hole. Cylindrical blower.

2. The aforementioned through holes are elongated vertically in the front-to-back direction and are provided in multiple locations. A cylindrical blower according to claim 1.

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