JP5879478B2 - Centrifugal blower - Google Patents

Description

  The present invention relates to a centrifugal blower used for an air-conditioning blower, a ventilation blower, or the like.

  Conventionally, this type of centrifugal blower is fixed by sandwiching a plurality of blade plates in an annular shape between a disk-shaped main plate connected to the rotating shaft of an electric motor and a donut-shaped suction shroud that is concentric with the main plate and has a suction port at the center. There has been known one provided with an impeller and a suction cylinder that guides air to the suction port of the suction shroud (see, for example, Patent Document 1).

  Hereinafter, the centrifugal blower will be described with reference to FIG.

  As shown in FIG. 4, the centrifugal blower 101 includes an impeller 103 having a suction shroud 102, a conical suction cylinder 104 that is tapered toward the impeller 103, and an end of the suction cylinder 104 concentric with the suction cylinder 104. The portion 105 includes a cylindrical mouse piece 106 connected so as to protrude inward, and the mouse piece 106 is inserted into the suction port 107 of the impeller 103 and fixed. In addition, when the mouse piece 106 and the suction port 107 come into contact with each other due to run-out of the impeller 103 or vibration due to imbalance, or foreign matter contained in the air to be blown is clogged, loss due to friction or generation of wear, The mouse piece 106 and the suction port 107 are configured to maintain a gap 108 so that destruction due to a collision does not occur.

  In the above configuration, when the impeller 103 rotates, the air flowing from the suction drum 104 due to the pressure-increasing action of the impeller 103 flows through the mouth piece 106 from the suction port 107 to the impeller 103 in the rotation axis direction, and changes the direction in the centrifugal direction. However, since a part of the air flowing out from the suction drum 104 forms a separation vortex 109 with the mouse piece 106 at the portion where the suction drum 104 protrudes inside the mouse piece 106, In order to reduce the pressure in the portion and attract the air flow, the air flowing from the suction cylinder 104 in the direction of the rotation axis is urged to smoothly change the direction in the centrifugal direction.

Japanese Patent No. 3325574

  At this time, since the pressure of the air at the suction port 107 is lower than that of the air flowing out from the impeller 103, a part of the air flowing out from the impeller 103 passes through the gap 108 between the mouth piece 106 and the suction port 107 of the impeller 103. A circulation flow 110 is formed which again flows into the suction port 107 of the impeller 103. In such a conventional centrifugal blower 1, when the circulation flow 110 ejected in the direction of the rotation axis from the gap 108 flows into the suction port 107, the suction cylinder 104 is formed. There was a problem that the flow in the centrifugal direction collides with the air flowing in from the centrifugal direction and disturbs the flow in the centrifugal direction to reduce the blowing performance.

  The present invention solves such a conventional problem, and a centrifugal blower that does not disturb the flow in the centrifugal direction by colliding with the main flow flowing into the impeller from the suction cylinder and does not reduce the blowing performance is provided. The purpose is to provide.

In order to achieve this object, the present invention includes an electric motor and a disk-shaped main plate coupled to a rotating shaft of the electric motor in an outer shell having a suction opening for sucking air and a discharge opening for discharging air. An impeller formed by annularly sandwiching a plurality of vanes with a donut-shaped suction shroud that is concentric with the main plate and sucks air at the center, and the suction shroud is formed in the suction opening of the outer shell said to direct the air to the suction port, and includes a suction cylinder and fixed with a gap between said suction shroud, said suction cylinder has a downstream portion for enlarging curved in the centrifugal direction toward the downstream side of A downstream end that is a tip of the downstream portion, and the suction cylinder is configured such that the downstream portion is a dielectric, an inner peripheral side electrode disposed on an inner peripheral surface on the downstream end side of the downstream portion, and Downstream And a periphery-side electrode which is installed on the circumferential surface, said downstream section, than the suction port of the suction shroud is inserted inside the impeller, towards the outer peripheral side electrode from the inner peripheral side electrode in the downstream end The configuration is such that an ion wind is induced by an electric field , thereby achieving the intended purpose.

  According to the present invention, it is possible to provide a centrifugal blower that does not reduce the blowing performance without colliding with the main flow flowing into the impeller from the suction cylinder and disturbing the flow in the centrifugal direction.

Side sectional view which shows the centrifugal blower of Embodiment 1 of this invention. Partial sectional view of the centrifugal blower Partial enlarged sectional view near the suction drum downstream of the multiblade fan Side sectional view showing a conventional centrifugal blower

The centrifugal blower according to claim 1 of the present invention includes an electric motor, a disk-shaped main plate and the main plate connected to a rotating shaft of the electric motor, in an outer shell having a suction opening for sucking air and a discharge opening for discharging air. And an impeller formed by sandwiching a plurality of vanes with a donut-shaped suction shroud having a suction port that sucks air in the center with a concentric circle, and the suction opening of the outer shell includes the impeller to direct air to the inlet, and includes a suction cylinder and fixed with a gap between said suction shroud, said suction cylinder, the downstream and a downstream portion to expand curved in the centrifugal direction toward the downstream side A downstream end that is a tip of a portion, and the suction cylinder includes an inner peripheral electrode disposed on an inner peripheral surface on the downstream end side of the downstream portion, and the downstream portion On the outer surface of And a periphery-side electrode which is location, said downstream portion, said suction than the suction port of the shroud are inserted inside the impeller, ions by the electric field towards the outer peripheral side electrode from the inner peripheral side electrode in the downstream end Centrifugal blower characterized by inducing wind.
It has a configuration.

As a result, the circulating flow that flows in from the gap between the suction cylinder and the suction shroud is separated from the suction cylinder by the ionic wind and turned in the centrifugal direction.Therefore, it collides with the main flow that flows into the impeller from the suction cylinder and causes the centrifugal flow to flow. Since the disturbance is suppressed and the main flow flowing from the suction drum by the ionic wind is promoted to turn in the centrifugal direction, the air blowing performance can be prevented from being reduced.

In addition , the inner peripheral electrode may be configured such that the surface is exposed so that there is no step difference from the downstream portion of the suction cylinder and is embedded in the centrifugal direction inner side than the outer peripheral electrode . Thereby, there is an effect that the turbulence of the airflow due to the step of the inner peripheral electrode can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1 to FIG. 3, the centrifugal blower 1 used as a blower for a building air conditioner has an inner size having a suction opening 2 for sucking air on a side surface and a discharge opening 3 for discharging air on another side surface. In a rectangular parallelepiped outer shell 4 having a width of 1,000 mm, a depth of 600 mm, and a height of 800 mm, a motor 5 fixed to the rack 5 so that the rotary shaft 6 is horizontal, and a rotary shaft 6 of the motor 7 An impeller 8 that is connected and blows air by rotation of the electric motor 7, and a suction cylinder 9 that is fixed to the outer shell 4 so as to guide the air from the suction opening 2 of the outer shell 4 to the impeller 8.

  Although the shape of the impeller 8 is determined by the required air blowing capacity for air conditioning, the impeller 8 of this example is a main plate having a diameter of 257 mm and a disk shape having a thickness of 2 mm connected to the rotating shaft 6 of the electric motor 7. 10 and a suction shroud 12 which is concentric with the main plate 10 and has a suction port 11 (inner diameter 144 mm) for sucking air in the center and has a thickness of 2 mm and a diameter of 257 mm, and extends vertically from the main plate 10 toward the suction shroud 12. A plate-like blade 13 having a thickness of 1.5 mm is formed by being annularly sandwiched at equal intervals. The blade 13 has an inner diameter of 155 mm, an outer diameter of 230 mm, an outlet width of 64.5 mm, and the blade 13 The turbofan impeller 8 has an inlet angle of the front edge 14 of 60 degrees in the rotational direction and an outlet angle of the rear edge 15 of the blade 13 is 45 degrees in the direction opposite to the rotational direction.

  The suction cylinder 9 has an inner diameter of 131 mm and a thickness of 3 mm. The flange portion 16 is fixed to the suction opening 2 of the outer shell 4, the bellmouth-shaped upstream portion that smoothly guides the flow, and the inner diameter toward the downstream side. And a downstream portion 17 that expands. Further, the suction cylinder 9 has a gap 18 of 3.5 mm at a minimum so that contact, friction loss, wear, breakage due to collision, etc. caused by vibration due to runout or unbalance of the impeller 8 do not occur. The suction shroud 12 and the rotation axis 6 are superposed.

  The downstream portion 17 of the suction cylinder 9 is a dielectric (for example, resin such as ABS, ceramic, etc.), and is made of a metal ring-shaped inner peripheral side electrode 19 installed on the inner peripheral side and a metal made installed on the outer peripheral side. The ring-shaped outer peripheral electrode 20 is provided, and an AC voltage is applied by a power source 21 electrically connected to the inner peripheral electrode 19 and the outer peripheral electrode 20. The inner peripheral electrode 19 has a surface exposed so that there is no step with the downstream portion 17 of the suction cylinder 9, is located on the inner side in the centrifugal direction than the outer peripheral electrode 20, and downstream of the air sucked from the suction port 11. Embedded in.

  The inner peripheral side electrode 19 and the outer peripheral side electrode 20 need only be separated to the extent that they can be provided with the dielectric material of the downstream portion 17 so that plasma can be generated, and there is a distance of 0.5 mm to 2 mm at the closest portion. desirable. If the thickness is smaller than 0.5 mm, dielectric breakdown may occur depending on the dielectric material. If the thickness is larger than 2 mm, a high voltage is required to generate plasma, and the capacity of the power source 21 needs to be increased.

  In the above configuration, when the impeller 8 is rotated by the electric motor 7, the air outside the outer shell 4 communicating with the suction opening 2 of the outer shell 4 passes through the suction drum 9 due to the pressure increasing action caused by the rotation of the blade plate 13 of the impeller 8. Then, the air introduced into the impeller 8 and discharged from the impeller 8 is discharged to the outside of the outer shell 4 through the discharge opening 3. When the centrifugal blower 1 is a blower for an air conditioner, the air sucked from the suction opening 2 is air from a device that adjusts temperature and humidity such as a heat exchanger, and the air discharged from the discharge opening 3 is through a duct or the like. An example is air that is carried to a space to be air-conditioned.

  Since the suction cylinder 9 is partly inserted into the impeller 8, the air from the suction cylinder 9 is reliably introduced into the impeller 8, but the intake of the impeller 8 is more than the air that has flowed out of the impeller 8. Since the pressure of the air at the mouth 11 is lower, a part of the air flowing out from the impeller 8 flows into the suction port 11 of the suction shroud 12 from the gap 18 between the suction cylinder 9 and the suction shroud 12 and flows through the circulation flow 22. Form.

  At this time, an AC voltage is applied by the power source 21 to the inner peripheral electrode 19 and the outer peripheral electrode 20 in the downstream portion 17 of the suction cylinder 9 (for example, the voltage is an effective value of 4 to 10 kV), and the applied voltage exceeds the discharge start voltage. And plasma 23 are generated, and electrons and ions are generated in the air. When they are driven by an electric field, a centrifugal ion wind 24 is induced at the downstream end 25 of the suction cylinder 9.

  As a result, the circulating flow 22 flowing in from the gap 18 between the suction cylinder 9 and the suction shroud 12 is turned in the centrifugal direction by the ion wind 24, so that it collides with the main flow 26 flowing into the impeller 8 from the suction cylinder 9 and moves in the centrifugal direction. Since the disturbance of the flow is suppressed and the main flow 26 flowing from the suction drum 9 by the ionic wind 24 is promoted to turn in the centrifugal direction, the air blowing performance can be prevented from being reduced.

  In a method of generating an air flow by a method other than the ion wind 24 and promoting the turning of the main flow 26 in the centrifugal direction, for example, a method of blowing out a jet and promoting the turning of the main flow 26 in the centrifugal direction, a special wind The structure becomes complicated, for example, the setting of the path is required, and the inner diameter of the suction cylinder 9 is reduced to make it difficult to suck the main flow 26. However, in the generation of the ion wind 24 of the present embodiment, such a problem occurs. The mainstream 26 can be promoted to turn in the centrifugal direction without any harmful effects.

  Moreover, since the inner peripheral side electrode of the downstream part of the suction drum is embedded in the downstream part without a step, the main flow 26 can be prevented from being disturbed by the step of the inner peripheral electrode.

  In addition, since the electric current which flows even if a high voltage is applied is very small, the electric power necessary for inducing the ionic wind is smaller than the electric power reduction amount of the electric motor 7 due to the improvement of the air blowing efficiency, and overall the air blowing performance is Reduction can be suppressed.

  The centrifugal blower of the present invention is useful as an application used for a blower for a building air conditioner or the like. Moreover, it is useful also as a use as blowers, such as a domestic air conditioning apparatus and an air cleaner.

DESCRIPTION OF SYMBOLS 1 Centrifugal blower 2 Opening for suction 3 Opening for discharge 4 Outer shell 5 Base 6 Rotating shaft 7 Electric motor 8 Impeller 9 Suction cylinder 10 Main plate 11 Suction port 12 Suction shroud 13 Blade plate 14 Front edge 15 Rear edge 16 Flange portion 17 Downstream portion 18 Gap DESCRIPTION OF SYMBOLS 19 Inner peripheral side electrode 20 Outer peripheral side electrode 21 Power supply 22 Circulating flow 23 Plasma 24 Ion wind 25 Downstream end 26 Mainstream

Claims (2)

A motor, a disk-shaped main plate connected to a rotating shaft of the motor, and a suction port for sucking air in a concentric circle with the main plate are provided in an outer shell having a suction opening for sucking air and a discharge opening for discharging air. and a impeller a plurality of slats in a donut-shaped suction shroud formed by sandwiching the ring, the suction opening of the shell, said to direct air to the suction port of the suction shroud and the suction A suction cylinder fixed with a gap between the shroud, the suction cylinder including a downstream portion that is curved and expands in a centrifugal direction toward the downstream side, and a downstream end that is a tip of the downstream portion; The suction cylinder includes a dielectric at the downstream portion, an inner peripheral electrode disposed on the inner peripheral surface on the downstream end side of the downstream portion, and an outer peripheral electrode disposed on the outer peripheral surface of the downstream portion. wherein the lower Parts, the suction than the suction port of the shroud are inserted inside the impeller, a centrifugal blower, characterized in that inducing the ion wind by an electric field towards the outer peripheral side electrode from the inner peripheral side electrode in the downstream end. 2. The centrifugal blower according to claim 1, wherein the inner peripheral side electrode is exposed such that a surface thereof is not stepped from a downstream portion of the suction cylinder and is embedded in a centrifugal direction inner side than the outer peripheral side electrode .

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