Cylindrical blower

Abstract

To reduce noise in a cylindrical blower with small diffusion of an airflow discharged from an air blowout port.SOLUTION: A cylindrical blower comprises a cylinder provided with an air suction port at its rear end and an air blowout port at its front end, and a fan provided inside the cylinder, and blows air by rotating the fan. On a cross section of the cylinder including the fan, an opening part is provided in at least a part of the cylinder, and preferably, the cylinder can be installed so that one side always faces upward and the other side always faces downward, and the opening part is provided on the underside of the cylinder.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Tubular fans are used in tunnel fans and blower application products such as hair dryers and air purifiers, as they create airflow in a limited area with little diffusion of the airflow.

[0003] Patent Document 1 discloses an airflow generating device that has a housing with an air intake at a first end and an air outlet at a second end, with a rotary fan and vanes (air straightening plates) for guiding air between them, and that generates little diffusion of the airflow. The rotary fan has blades, and it is said that noise can be reduced by changing the number of blades and vanes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2007-529681 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventor has developed a fan that can be used in a relatively quiet environment such as an office and can change direction to blow air to a specific location such as a place where people are present. In this case, the housing of the fan is exposed in order to change the direction, so noise may be more noticeable than with ceiling-embedded fans. Therefore, the present inventor set a development goal of reducing noise when developing a cylindrical fan with less diffusion of airflow. [Means for solving the problem]

[0006] The present invention is a cylindrical blower that includes a tube having an air intake at a rear end and an air outlet at a front end, and a fan provided inside the tube, and that blows air by rotating the fan, wherein an opening is provided in at least a part of the tube in a cross section of the tube that includes the fan.

[0007] In the present invention, the cylinder can be installed so that one side always faces upward and the other side always faces downward, and the opening may be provided on the underside of the cylinder.

[0008] In the present invention, a baffle plate may be provided inside the cylinder and in front of the fan.

[0009] In the present invention, the opening may be provided in at least a part of the tube behind the fan.

[0010] In the present invention, a plate covering the opening may be provided on at least the upper side of the outside of the tube.

[0011] In the present invention, a flexible film may be attached to the opening so as to cover the opening. Effect of the Invention

[0012] In the present invention, the noise can be reduced by providing an opening in the tube of the tubular blower in the region surrounding the fan. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a cylindrical fan according to a first embodiment; [Diagram 2] FIG. 3 is an axial cross-sectional view of the cylindrical fan according to the first embodiment. [Diagram 3] FIG. 1 is a simulation diagram of the airflow of the cylindrical fan of the first embodiment. [Figure 4] FIG. 1 is a diagram showing the frequency and sound level of the sound generated by the cylindrical fan of the first embodiment. [Diagram 5]FIG. 1 is a perspective view of a cylindrical fan according to a modified example of the first embodiment. [Figure 6] FIG. 1 is a simulation diagram of an air flow for examining a cylindrical fan according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a perspective view of a cylindrical fan according to a second embodiment. [Figure 8] FIG. 11 is a perspective view of a cylindrical fan according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Embodiment 1> <Configuration> The cylindrical fan 100 of this embodiment can be attached to a wiring duct 180, and the direction of airflow can be changed as required.

[0015] Fig. 1 is a perspective view of a cylindrical fan 100B. In the following description, the terms F direction, B direction, U direction, and D direction are used based on the axis AX in Fig. 1. The direction perpendicular to the axis AX and the up-down direction is sometimes referred to as left and right.

[0016] 1, cylindrical blower 100B includes a cylinder 110 having air inlet 120 at its rear end and air outlet 130 at its front end, and cylinder 110 is divided into rear cylinder portion 111 and front cylinder portion 112B. Arm 170 is rotatably attached to the side surface of rear cylinder portion 111, and mounting portion 178 is located at the other end of arm 170 and is attached to wiring duct 180.

[0017] As the front cylinder portion, a front cylinder portion 112A without a through hole on the side, a front cylinder portion 112B with a through hole 115B as an opening in the lower half of the side, and a front cylinder portion 112C with a through hole 115C as an opening around the entire circumference of the side were prototyped, but Fig. 1 shows the front cylinder portion 112B as a representative. Cylindrical fans using the front cylinder portions 112A, 112B, and 112C are respectively referred to as cylindrical fans 100A, 100B, and 100C, and are collectively referred to as the front cylinder portion 112 and the cylindrical fan 100. The through holes 115B and 115C are also collectively referred to as the through hole 115.

[0018] The through holes 115 are provided in a plurality of positions, each long in the front-rear direction. This is because a portion serving as a "pillar" that provides mechanical strength to the front tube portion 112 is required between the through holes, and the size of the through holes is set so that fingers cannot be inserted therein, ensuring safety.

[0019] The axis AX, which is the orientation of the cylindrical fan 100, can be rotated horizontally by rotating the arm 170 in the Φ direction relative to the mounting part 178. In addition, the orientation can be changed from downward to upward as appropriate by rotating the rear cylindrical part 111 in the θ direction relative to the arm 170.

[0020] Cylindrical blower 100 can be turned on and off and its airflow volume can be controlled by communication using radio waves or infrared rays from control device 190, which may be a tablet, smartphone, PC, or remote control.

[0021] 2(a) is a cross-sectional view including axis AX of cylindrical fan 100B. Inside cylindrical fan 100B, there are power supply 140, motor 151, fan 152 rotated by motor 151, and air straightening vane 160. As fan 152 rotates, air flow W passes through the space between power supply 140 and rear cylindrical portion 111, and is discharged in direction F.

[0022] 2(b) is a view of the cylindrical fan 100B seen from the F side (front side) of the air outlet 130. It can be seen that there are eight straightening vanes 160 and three fans 152.

[0023] The length from air intake 120 to air outlet 130 of cylindrical blower 100B is 190 mm, the length of rear cylindrical portion 111 is 65 mm, the length of front cylindrical portion 112 is 125 mm, and the outer diameter of air intake 120 / air outlet 130 is 85 mm, but cylindrical blowers of different sizes are also under consideration.

[0024] <Fan and through holes> Referring again to FIG. 2(a), a point S1 is a projection of a plane including the front end 152F of the fan and perpendicular to the axis AX onto the front cylinder portion 112, a point S2 is a projection of a plane including the rear end 152B of the fan and perpendicular to the axis AX onto the front cylinder portion 112, and the distance between S1 and S2 is L. f The midpoint between S1 and S2 is S3. The range in which the through holes 115 are provided is L h In the front cylinder portion 112B, the range L f The range L of the through hole 115 is h 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 spacing between the through holes is 2.6 mm, and there are 16 through holes.

[0025] <Air flow simulation> FIG. 3(a) shows the results of a simulation of the internal airflow of a cylindrical fan 100A using a front cylindrical portion 112A without any through holes, and FIG. 3(b) shows the results of a simulation of the internal airflow of a cylindrical fan 100C using a front cylindrical portion 112C having through holes 115C around the entire circumference.

[0026] 3(a) and (b) show the widths DA and DC of the airflow at the air outlet 130. It can be seen that the through-hole 115C affects the width of the airflow because the width DC is narrower than the width DA. In the original diagram, 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, but the arrows indicating the DA airflow are dark gray (original green (medium)) and the arrows indicating the DC airflow are light gray (original yellow (slightly strong)), which is a consistent result that the smaller the width of the airflow, the stronger the air volume. From this, it can be assumed that the provision of the through-hole 115C narrows the width of the airflow, which in turn strengthens the directionality of the airflow and reduces the diffusion of the airflow.

[0027] Also, for example, point P in FIG. 3(a) in front of fan 152 is dark gray (original red (strong)), and for example, point Q in FIG. 3(a) behind fan 152 is medium airflow (original green (medium)). The same is true for the front and rear of fan 152 in FIG. 3(b). Meanwhile, since the airflow exiting through hole 115C and the airflow entering through hole are not depicted in FIG. 3(b), it can be seen that the intake and exhaust of air at through hole 115C is so small that it is not shown, and through hole 115C does not substantially function as an "air intake" or "air exhaust".

[0028] 3(a) and (b), a difference can be seen, particularly near the front end 152F of the fan, where the width of the airflow is wider in Fig. 3(a) and narrower in Fig. 3(b). For this reason, we believe it would be best to position the through-hole so as to include at least point S1, which is the projection of the front end 152F of the fan onto the cylinder.

[0029] The inventors have assumed the following model regarding the effect of the through-hole on the air flow. For example, at point T near the front tube part 112 in FIG. 3(a), if the fan is at the rear, the pressure is high, and if the fan is at the front, the pressure is low. The rotation of the fan causes the high and low pressure states to alternate, resulting in pressure fluctuations. Here, if the through-hole 115 is opened in the front tube 112, it is possible for air to instantly enter and exit through the through-hole 115, so it is estimated that the pressure fluctuations are reduced. If this pressure fluctuation is considered to be one of the causes of noise, it can be explained that the noise can be reduced by opening a through-hole in the tube next to the fan. Before the experiment, it was thought that the through-hole would be a passage for sound, which would cause noise to escape, and increase the noise. In reality, even if sound comes out of the through hole, the object that the air is blowing on is in the front (direction F), and in most cases people are also in front, whereas the sound coming out of the through hole spreads mainly in the direction D, etc. Therefore, it can be said that the cylindrical fan 100A or 100B, which is a ceiling-mounted fan, has a structure that is particularly suitable for reducing noise when installed on the ceiling of a store, office, etc.

[0030] <Noise measurement results> The noise measurement results for cylindrical fans 100A, 100B, and 100C when the same power was input were 38.9 dB, 36.6 dB, and 36.1 dB, respectively. Note that the noise (dB) is the SPL value (Sound Pressure Level) with A-weighting, which is a frequency weighting corresponding to the human hearing.

[0031] The above noise is the overall noise, but Fig. 4 shows the results of noise spectrum measurement broken down by sound frequency. The vertical axis is the SPL for each frequency, the horizontal axis is the sound frequency f (Hz), and lines 100A, 100B, and 100C show the noise by frequency for cylindrical fans 100A, 100B, and 100C, respectively. In Fig. 4, the trends may differ depending on the frequency, but at least in the frequency range enclosed by the square, the SPL is in the following relationship: 100A>100B>100C, confirming that 100C has a noise reduction effect.

[0032] From the viewpoint of noise reduction, cylindrical fan 100C having through holes on the entire circumference of front cylindrical portion 112 is suitable, but providing through holes on the U side (upper side) of front cylindrical portion 112 poses another problem of dust intrusion. Taking this into consideration, cylindrical fan 100B having through holes on the lower side of front cylindrical portion 112 is preferable.

[0033] If the through-hole 115 is extended forward from the side of the fan of the front cylinder portion 112, the directivity of the air flow, which is a feature of the cylindrical blower, is lost, and there is a concern that the flow will be diffused. Therefore, it is preferable not to extend the through-hole too far forward. The length added to the front side of the point S1 where the front end 152F of the fan is projected is L. f I think the following is good.

[0034] <Rectifier plate> 2(a) and (b) has the function of straightening the airflow, and also functions to prevent fingers from touching the fan 152. The number of straightening plates 160 facing outward from the axis AX is eight, but the number may be four, six, eight, twelve, etc.

[0035] <Power supply> Power supply 140 is installed between air intake port 120 and fan 152 in tube 110. Power supply 140 has a cylindrical outer shape and is made small so as to ensure an air passage between power supply 140 and the inner surface of tube 110. Power supply 140 converts AC, which is commercial power input from a wiring duct, into DC.

[0036] The power source may be provided, for example, in attachment portion 178, rather than in cylinder 110. This reduces air resistance inside the cylinder, and increases the amount of airflow. Furthermore, rear cylinder portion 111 may be eliminated.

[0037] <Operation control> The cylindrical fan can be operated on a schedule by the control device 190. Scheduled operation can turn the fan ON when the store opens or when work starts, and OFF when the store closes or when work ends, allowing the fan to have a strong or weak airflow depending on the time of day. In addition, sensor-linked operation can be performed using a sensor that can communicate with the control device 190, allowing the fan to be controlled according to the temperature, humidity, and human density measured by the sensor.

[0038] <Modification 1 of cylindrical fan 100C> Although the cylindrical fan 100C with through holes 115C provided around the entire circumference of the front cylinder portion is excellent in terms of reducing noise, it has a problem of dust getting inside. Therefore, in the cylindrical fan 100D of the first modification shown in a perspective view in Fig. 5, a plate 117 equivalent to a roof is installed above the through holes 115C with a small space therebetween. As a result, even if the through holes 115C are provided around the entire circumference, dust is blocked by the plate 117, making it difficult for dust to get inside the cylinder. The plate 117 may be provided around the entire circumference of the front cylinder portion 112C.

[0039] <Modification 2 of cylindrical fan 100C> In the cylindrical blower 100E (not shown) of the second modification, the through holes 115C are provided all around, and at least the inner or outer surface of the upper through hole 115C is covered with a thin film. 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 the fluctuation in air pressure caused by the rotation of the fan. This makes it possible to achieve both dust prevention and noise reduction. Note that the opening or through hole covered with a film that can vibrate in response to the fluctuation in air pressure has the same function as a normal opening or through hole from the viewpoint of noise reduction, so the same name (opening or through hole) is used, and an explanation is added as "opening or through hole that can transmit the instantaneous pressure fluctuation inside the cylinder to the outside of the cylinder" as necessary.

[0040] <Embodiment 2> <Configuration> The cylindrical fan 100F of the second embodiment has a through hole 114B in the lower half of the periphery of the rear cylindrical portion 111B in addition to the through hole 115B near the fan.

[0041] As a preliminary step to this embodiment, we investigated the effect of through holes 114C when "through holes 114C" are provided around the entire circumference of rear cylinder portion 111 in 100A, which does not have any through holes near the fan. The results of the airflow simulation in this case are shown in Figure 6. The width DE of the airflow at air outlet 130 is slightly larger than DA in Figure 3(a).

[0042] Based on the above findings, a prototype of cylindrical fan 100F was produced. A perspective view of the prototype is shown in Fig. 7. It was found that cylindrical fan 100F did not achieve much further noise reduction effect compared to cylindrical fan 100B, but the air volume was slightly increased. In other words, when compared at the same air volume, noise was slightly reduced.

[0043] From this result, it is suitable to use through hole 114 (through hole 114C or through hole 114B with dust countermeasures taken into consideration) together with through hole 115 (through hole 115C or through hole 115B with dust countermeasures taken into consideration). Note that through hole 114 may be provided as a long hole continuous with through hole 115.

[0044] <Embodiment 3> <Configuration> In a cylindrical fan 100G of the third embodiment, an opening 115G near the fan is provided in a front cylindrical portion 112G.

[0045] 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.

[0046] In this embodiment, the area of ​​the opening can be made larger than that of the through-hole shaped opening used in the first and second embodiments, and the noise reduction effect is enhanced.

[0047] Although the opening 115G is provided in the lower half of the front cylinder 112G, it may be provided around the entire circumference. In that case, the front cylinder may be supported by, for example, a shaft provided on the motor side, or may be supported by a guard wire 116.

[0048] <Modification> The above describes an embodiment of a tubular blower according to the present invention. However, the exemplified tubular blower can be modified, for example, as described below, and it goes without saying that the present invention is not limited to the tubular blower as shown in the above embodiment.

[0049] Although each embodiment has been described as a simple cylindrical fan, the present invention can be applied to fan application products such as dryers, which are cylindrical fans that blow warm air, air purifiers with built-in air cleaning filters and sterilization / virus inactivation devices, and large fans used for tunnel ventilation, etc. Also, the present invention may be used as a fan in the front stage of a bladeless fan, for example.

[0050] The term "cylindrical" is not limited to a cylindrical shape, and may be a curved cylindrical shape as described in Prior Art Document 1. The cylinder may be linear with respect to the axis AX as in each embodiment, or the cylinder may be curved.

[0051] In each embodiment, the front cylinder, which adjusts the direction of the fan and the airflow, and the rear cylinder, which houses the power supply, are separate members, but they may be one integral member. If the front and rear cylinders are separated, the fan may be located inside the rear cylinder. The front cylinder portion near the fan and the portion in front of it may be separate members. The rear cylinder portion that houses the power supply may not be required.

[0052] In each embodiment, the arm is attached to the side surface of the rear cylinder, but the attachment position of the arm is not limited to this, and it may be attached to the front cylinder or to the air intake port side.

[0053] There are fans / circulators with a protective frame surrounding the fan as intermediate shapes between electric fans and cylindrical fans, but when it is necessary to clarify the difference between these and the present invention, it is preferable that the length of the tube (the sum of the length of the front tube and the length of the rear tube) is at least 1 time, preferably at least 1.3 times, and more preferably at least 1.5 times longer than the outer diameter of the air intake. Also, it is preferable that the opening (through hole) is provided so as to include the length from point S1 where the front end 152F of the fan is projected to point S2 where the rear end 152B of the fan is projected, and it is preferable that the opening is provided so as to include the length from S1 to the midpoint S3, and it is preferable that the opening is provided so as to include S1. It is preferable that a straightening plate is provided in front of the fan inside the tube. At least a length L is provided in front of the front end of the fan of the tube. f or longer than L h It is preferable that there is an area without the above openings (openings of a size that has little effect on the air flow may be provided).

[0054] The "lower side" where the through holes are provided in cylindrical blower 100B 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 right side and left side may be included, may be partially included, or may not be included.

[0055] Although the cylindrical fan of the present invention is described as being attached to a wiring duct rail in each embodiment, the cylindrical fan of the present invention may be directly attached to the ceiling without using a wiring duct rail when installing the fan on the ceiling. Also, the fan does not have to be of the ceiling-mounted type, and may be used in a manner that does not require a fixed installation.

[0056] The through hole is preferably a hole long in the axis AX direction, and the ratio of the axial length to the width direction is preferably 3 to 20 times, more preferably 5 to 10 times.

[0057] It should be noted that the above-described embodiments disclosed herein are illustrative in all respects and are not intended to be a basis for a restrictive interpretation. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined based on the claims. Also, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0058] 100, 100A, 100B, 100C, 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 cylindrical fan includes a cylinder having an air intake at a rear end and an air outlet at a front end, and a fan disposed inside the cylinder, the fan rotating to blow air, A cylindrical blower, wherein an opening is provided in at least a part of the cylinder in a cross section including the fan.

2. The cylinder can be installed so that one side always faces upward and the other side always faces downward; The opening is provided on the underside of the tube. The cylindrical blower according to claim 1.

3. A straightening vane is provided in front of the fan inside the cylinder. The cylindrical blower according to claim 1.

4. The opening is provided in at least a part of the tube on the rear side of the fan. The cylindrical blower according to claim 1.

5. A plate covering the opening is provided at least on the upper side of the outside of the tube. The cylindrical blower according to claim 1.

6. A flexible film is attached to the opening so as to cover the opening. The cylindrical blower according to claim 1.

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