JP2011127526A - Centrifugal blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal blower enabling the size reduction of a regenerative resistor, and advantageous for downsizing the installation space of the centrifugal blower including the regenerative resistor. <P>SOLUTION: Air is sucked in from a first cover side suction port 50 and a second cover side suction port 52 by rotation of an impeller 22, and this air is sucked in the axial direction of the impeller 22 from a suction port 2408 by passing through a cover side wind guide passage 48. The regenerative resistor 32 is connected to an inverter 30 via a connecting wire 3206, and imparts braking force to a motor 28 by consuming regenerative electric power generated from the motor 28 as heat when decelerating the motor 28, The regenerative resistor 32 is arranged in the vicinity of the second cover side suction port 52 in the cover side wind guide passage 48 so that the whole surface area of a resistor body 3202 is exposed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a centrifugal blower.

The centrifugal blower includes an impeller, a fan casing that houses the impeller, and a motor. The centrifugal blower rotates the impeller with the motor to blow air.
When a centrifugal blower is used, for example, for supplying combustion air to a combustion apparatus of a boiler and the burner is controlled by switching to three stages of high combustion, low combustion, and stop, depending on high combustion and low combustion It is necessary to switch the supply amount of combustion air.
In this case, in order to reduce the power consumption of the motor, the number of rotations of the motor is increased or decreased using an inverter.
Furthermore, in order to perform combustion control with good responsiveness in accordance with load fluctuations on the boiler side, it is necessary to switch the supply amount of combustion air in the centrifugal blower in a short time.
For this reason, the inverter is required to shorten the motor deceleration time when the motor is decelerated.
Therefore, a centrifugal blower that generates a braking force in the motor by providing a regenerative resistor (braking resistor) that consumes the regenerative power generated when the motor decelerates, thereby shortening the motor deceleration time. Is provided (see Patent Document 1).

JP 2003-336835 A

On the other hand, when a regenerative resistor is provided in a centrifugal blower used for supplying combustion air to a combustion apparatus of a boiler, when the regenerative resistor consumes the regenerative power supplied from the motor, the regenerative resistor The temperature rises to several hundred degrees.
Therefore, in order to naturally cool the regenerative resistor, it is necessary to use a regenerative resistor having a large surface area and to arrange the regenerative resistor in a wide accommodation space.
Therefore, when a regenerative resistor is provided in a centrifugal blower used for supplying combustion air to a combustion apparatus of a boiler, these large regenerative resistors and a large storage space are required. The installation space of the included centrifugal blower increases, and there is a problem that the combustion apparatus including the centrifugal blower is enlarged.
The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the size of the regenerative resistor and to reduce the installation space of the centrifugal fan including the regenerative resistor. Is to provide a simple centrifugal blower.

In order to achieve the above object, an invention according to claim 1 includes an impeller, a fan casing in which the impeller is accommodated and provided with a suction port and an outlet, and a motor that rotationally drives the impeller. A centrifugal blower that sucks air from the suction port by rotation and blows out the sucked air from the blower port, the inverter controlling the number of rotations of the motor, and the regenerative power of the motor connected to the inverter A regenerative resistor to be consumed is provided, and the regenerative resistor is disposed at a location where the regenerative resistor strikes the flow of air sucked into the suction port.
The invention according to claim 2 is characterized in that the regenerative resistor has an elongated shape, and the regenerative resistor is arranged with its longitudinal direction orthogonal to the air flow. It is a type blower.
The invention according to claim 3 is the centrifugal blower according to claim 1 or 2, wherein the regenerative resistor is arranged so that the entire surface thereof is in contact with the flow of air.
According to a fourth aspect of the present invention, the centrifugal blower further includes a cover coupled to the fan casing, and the cover includes a cover-side air guide path connected to the suction port, and the cover-side air guide path. The centrifugal blower according to any one of claims 1 to 3, wherein the regenerative resistor is disposed in the cover side air guide path. is there.
The invention according to claim 5 is the centrifugal blower according to any one of claims 1 to 4, wherein the centrifugal blower is used for supplying combustion air to a combustion apparatus of a boiler. .

According to the first aspect of the present invention, since the regenerative resistor is disposed at a location that abuts against the air flow sucked into the suction port, the regenerative resistor can be forcibly cooled by the air flow, and the regenerative resistance This is advantageous for efficient cooling of the vessel.
Therefore, it is advantageous in reducing the size of the regenerative resistor as compared with the case where the regenerative resistor is naturally cooled, and is advantageous in reducing the installation space of the centrifugal blower including the regenerative resistor.
According to the second, third, and fourth aspects of the invention, it is advantageous to efficiently cool the regenerative resistor.
According to the invention described in claim 5, since the air heated against the regenerative resistor is used for supplying combustion air to the combustion apparatus of the boiler, the combustion air can be preheated, This is advantageous for effective use of heat.

It is a schematic block diagram of the boiler 10 using the combustion apparatus 16 with which the centrifugal air blower 20 of this Embodiment was applied. 1 is a perspective view of a centrifugal blower 20. FIG. 3 is a front view of the centrifugal blower 20. 3 is a front view of the centrifugal blower 20 with a front plate 40 removed from a cover 26. FIG. 3 is a side view of the centrifugal blower 20. FIG. FIG. 3 is a plan view of the centrifugal blower 20. It is AA sectional view taken on the line of FIG. FIG. 4 is a sectional view taken along line BB in FIG. 3. 3 is a perspective view of a regenerative resistor 32. FIG. FIG. 3 is a perspective view of the centrifugal blower 20 with a cover 26 removed.

Next, an embodiment in which the centrifugal blower of the present invention is applied to the combustion apparatus of the boiler 10 will be described.
As shown in FIG. 1, the boiler 10 includes a boiler can body 12, a water supply pump 14, and a combustion device 16.
The boiler can body 12 includes a lower header 1202, an upper header 1204, a plurality of water pipes 1206 that connect the headers 1202 and 1204, and a combustion chamber 1208 positioned inside the plurality of water pipes 1206. ing.
The water supply pump 14 supplies water to a plurality of water pipes 1206 through a water supply pipe 1402 and a lower header 1202.
The combustion device 16 burns fuel in the combustion chamber 1208, heats the water in the water pipe 1206 with the combustion gas, and generates steam in the water pipe 1206.
The steam generated in the water pipe 1206 is collected by the upper header 1204 and sent out from the steam pipe 1210 to the load side.

The combustion device 16 includes a burner 1602, a wind box 1604, a blower duct 1606, a control unit 1608, a centrifugal blower 20 according to the present invention, an inverter 30, and a regenerative resistor 32. .
The burner 1602 is provided in the upper center of the boiler can body 12 toward the combustion chamber 1208.
Fuel is supplied to the burner 1602 through a fuel supply pipe 1612, and combustion air is supplied to the burner 1602 through the centrifugal blower 20, the air duct 1606, and the wind box 1604, and fuel and combustion air are supplied. The mixed air-fuel mixture is ignited and burned by an ignition electrode rod (spark rod) (not shown).
The air duct 1606 is provided with a damper 1610 for adjusting the air volume.
The inverter 30 controls the rotation speed of the motor 28 by controlling the frequency of the AC power supplied to the motor 28 based on the control signal supplied from the control unit 1608.
The control unit 1608 controls the start and stop of the motor 28 of the centrifugal blower 20 via the inverter 30 according to the start and stop of the operation of the burner 1602.
The control unit 1608 controls the opening degree of the damper 1610 in accordance with the amount of combustion of the burner 1602 and also controls the rotation speed of the motor 28 of the centrifugal blower 20 via the inverter 30.
That is, the control unit 1608 controls the supply and stop of supply of combustion air to the burner 1602 by controlling the start and stop of the motor 28 of the centrifugal blower 20. Further, the control unit 1608 controls the amount of combustion air supplied to the burner 1602 by controlling the opening degree of the damper 1610 and the rotational speed of the motor 28 of the centrifugal blower 20.

Next, the centrifugal blower 20 will be described.
As shown in FIGS. 2 to 8, the centrifugal blower 20 includes an impeller 22, a fan casing 24, a cover 26, and a motor 28, and an inverter 30 (FIG. 1) and a regenerative resistor 32 are provided. It has been.

As shown in FIG. 8, the impeller 22 is arranged with a circular main plate 2202, a curved side plate 2204 arranged in front of the main plate 2202, and a space in the circumferential direction between the main plate 2202 and the side plate 2204. A plurality of blades 2206.
A rotation shaft 2802 of the motor 28 is connected to the main plate 2202, and the impeller 22 is rotated by the motor 28, whereby air is sucked in the axial direction from the central inlet 2208 of the side plate 2204, and this air is sucked into the main plate 2202 and the side plate 2204. The air is blown out radially outward of the main plate 2202 through the air passage formed by the blades 2206.

As shown in FIG. 8, the fan casing 24 includes a rear wall 2402 positioned behind the main plate 2202, a front wall 2404 positioned in front of the rear wall 2402, and a peripheral wall connecting the periphery of the rear wall 2402 and the front wall 2404. 2406 and accommodates the impeller 22 therein.
An opening having a diameter larger than that of the impeller 22 is formed in the front wall 2404, and a suction port casing 34 is attached to the front wall 2404 so as to close the opening.
As shown in FIGS. 8 and 10, the inlet 2208 of the impeller 22 is exposed in the central opening of the inlet casing 34, and the central opening serves as the inlet 2408 of the fan casing 24.
An opening is formed in the center of the rear wall 2402, and the front end of the motor case 2802 of the motor 28 is attached so as to close the opening.
The outer peripheral portion of the rear wall 2402, the outer peripheral portion of the front wall 2404, and the peripheral wall 2406 form an air guide path 36 that uses air blown radially outward from the impeller 22 as a swirling flow. An air outlet 2410 (FIG. 2) is provided on the extension of the air passage 36.
Therefore, when the impeller 22 is rotated by the motor 28, air is sucked in from the suction port 2408 in the axial direction of the impeller 22, and the sucked air is pressurized through the air guide path 36 toward the outlet 2410, The air is blown out from the outlet 2410 in the tangential direction of the outer periphery of the impeller 22. Then, the air blown out from the outlet 2410 is supplied to the burner 1602 via the air duct 1606 and the wind box 1604.

The cover 26 is disposed in front of the front wall 2404 of the fan casing 24 and the inlet casing 34 as shown in FIGS.
2, 4, 6, and 7, the cover 26 includes a rear plate 38 located on the fan casing 24 side, a front plate 40 disposed in front of the rear plate 38, and upper and lower partition plates. 42, 44.
The back plate 38 has an opening 46 as shown in FIG. 7, and the back plate 38 has an annular portion 3802 extending along a half of the opening 46 and the remaining portion of the opening 46 as shown in FIG. It has a bulging portion 3804 that extends along the half and bulges to the side.
The rear plate 38 is attached to the front wall 2404 of the fan casing 24 via bolts.

  As shown in FIGS. 2 and 5, the upper and lower partition plates 42 and 44 are integrally formed at upper and lower portions of the bulging portion 3804 of the rear plate 38 and are provided so as to protrude forward from the upper and lower portions. It has been.

As shown in FIGS. 2 and 3, the front plate 40 bulges from the semicircular portion 4002 having an outer diameter corresponding to the annular portion 3802 of the rear plate 38, and bulges from the semicircular portion 4002 to the side. A bulging portion 4004 having a shape corresponding to the portion 3804.
2 and 5, the front plate 40 is connected to the upper and lower partition plates 42 and 44 via bolts 4010 and nuts, so that the front plate 40 is connected by the rear plate 38. It is supported.

In the present embodiment, as shown in FIG. 8, a thin sound absorbing material 54 is attached to the surface of the front plate 40 facing the rear plate 38. The sound absorbing material 54 is for reducing noise generated when the centrifugal blower 20 is driven.
The sound absorbing material 54 is formed in a circular shape centered on the center of the suction port 2408.

In the present embodiment, an air filter 56 that removes dust in the air is provided between the sound absorbing material 54 and the rear plate 38.
The air filter 56 is disposed via a frame 58.
As shown in FIG. 8, the frame 58 includes a base portion 5802 attached to the front wall 2404 of the fan casing 24, and a cylindrical surface portion 5804 connected to the base portion 5802 and extending in the shape of a cylindrical surface around the center of the suction port 2408. And a circular front surface portion 5806 connecting the outer periphery of the front end of the cylindrical surface portion 5804.
The cylindrical surface portion 5804 and the front surface portion 5806 have a structure that allows air to flow and can hold the air filter 56.
The base portion 5802 is formed so that all the air flowing in from the cylindrical surface portion 5804 and the front surface portion 5806 is guided to the suction port 2408 and is airtightly attached to the front wall 2404 of the fan casing 24.
The air filter 56 has a circular front surface portion 5602 attached to the front surface portion 5806 and an outer peripheral surface portion 5604 attached to the cylindrical surface portion 5804. For mounting the air filter 56 to the frame 58, various conventionally known configurations such as mounting brackets can be employed.

Therefore, as shown in FIG. 8, a cover side air guide path 48 is formed between the front plate 40 and the rear plate 38, which is connected to the suction port 2408 via the opening 46 and in which the air filter 56 is disposed.
Further, as shown in FIGS. 2 and 8, the first extending in the shape of a semi-cylindrical surface between the outer peripheral edge of the annular portion 3802 of the rear plate 38 and the outer peripheral edge of the semicircular portion 4002 of the front plate 40. The cover side suction port 50 is formed, and a vertically long rectangular shape is formed between the tip of the bulging portion 3804 of the rear plate 38, the tip of the bulging portion 4004 of the front plate 40, and the tips of the upper and lower partition plates 42 and 44. A second cover side suction port 52 extending in the direction is formed.
Accordingly, the rotation of the impeller 22 causes air to be sucked from the first cover side suction port 50 and the second cover side suction port 52, and this air passes through the cover side air guide path 48 and is air dust 56. Is removed, and clean air is sucked into the suction port 2408.

As shown in FIGS. 2, 4, and 5, the regenerative resistor 32 is air that is sucked into the suction port 2408 in the cover-side air guide path 48 between the second cover-side suction port 52 and the air filter 56. It is arranged at the location that hits the flow of the.
More specifically, the regenerative resistor 32 is provided in the vicinity of the second cover side suction port 52 in the cover side air guide path 48.
By providing the upper and lower partition plates 42 and 44, an air flow from the second cover side suction port 52 toward the air filter 56 is formed, and the regenerative resistor 32 is disposed in the air flow. That is, the regenerative resistor 32 is disposed at a position that does not obstruct the flow of air from the first cover side suction port 50 that becomes the mainstream.
Further, the regenerative resistor 32 has an elongated shape, and is arranged such that its longitudinal direction is perpendicular to the air flow, and the entire surface thereof is in contact with the air flow. Since the portion of the cover side air guide path 48 in the vicinity of the second cover side suction port 52 is a vertically long rectangle, the regenerative resistor 32 is arranged with its longitudinal direction directed vertically.
The regenerative resistor 32 is located below the upper partition plate 42.
Therefore, even if the location where the centrifugal blower 20 is installed is a location where the centrifugal blower 20 is exposed to rainwater or dust, it is advantageous to protect the regenerative resistor 32 from rainwater, dust, or foreign matter by the upper partition plate 42.
In addition, by providing the upper and lower partition plates 42 and 44, a flow path in which cooling air effectively contacts the regenerative resistor 32 can be formed.

More specifically, as shown in FIGS. 4 and 9, the regenerative resistor 32 includes a resistor main body 3202 having an elongated shape, attachment pieces 3204 provided at both ends in the longitudinal direction of the resistor main body 3202, a resistance And two connection lines 3206 led out from one end of the main body 3202. Each attachment piece 3204 is provided with an attachment hole 3208.
As shown in FIG. 5, the regenerative resistor 32 has U-shaped spacers 60 provided above and below the location of the rear plate 38 in the vicinity of the second cover side suction port 52. By being attached, the entire surface of the resistor main body 3202 is disposed so as to be exposed.
As shown in FIGS. 2 and 5, the two connection lines 3206 protrude through the insertion hole of the lower partition plate 44 and below the lower partition plate 44.

The regenerative resistor 32 is connected to the inverter 30 via a connection line 3206, and applies a braking force to the motor 28 by consuming regenerative power generated from the motor 28 as heat when the motor 28 decelerates.
That is, when the motor 28 is decelerated, the regenerative resistor 32 and the motor 28 are brought into conduction by the control of the inverter 30, whereby regenerative power is supplied to the regenerative resistor 32. Except when the motor 28 is decelerated, the regenerative resistor 32 and the motor 28 are made non-conductive by the control of the inverter 30.

According to the present embodiment, the following operational effects are achieved.
That is, when the regenerative resistor 32 provided in the centrifugal blower 20 used for supplying combustion air to the combustion device 16 of the boiler 10 is naturally cooled, the regenerative resistor 32 has, for example, several kW of power consumption. There is a need for large ones.
On the other hand, in the present embodiment, the regenerative resistor 32 is disposed at a location that abuts against the air flow sucked into the suction port 2408, so that the regenerative resistor 32 can be forcibly cooled by the air flow. This is advantageous in efficiently cooling the regenerative resistor 32.
Therefore, the regenerative resistor 32 may be a small one having a power consumption of about 500 W, for example.
That is, it is advantageous in reducing the size of the regenerative resistor 32 as compared with the case where the regenerative resistor 32 is naturally cooled, and therefore, it is advantageous in reducing the accommodation space for accommodating the regenerative resistor 32. The installation space of the centrifugal blower 20 including the resistor 32 can be made compact, which is advantageous in reducing the size of the combustion device 16.

  Further, since the air hitting the regenerative resistor 32 is heated, the heated air is supplied from the centrifugal blower 20 to the burner 1606, so the combustion air is preheated. Therefore, since the heat generated in the regenerative resistor 32 is used as a part of energy for heating the boiler 10, it is advantageous for effective use of heat.

Moreover, according to this Embodiment, since the regenerative resistor 32 is provided between the 2nd cover side suction inlet 52 and the air filter 56, when the centrifugal air blower 20 stops, it is open | released to air | atmosphere. The heat release of the regenerative resistor 32 in the direction of the second cover side suction port 52 is not hindered by the air filter 56, which is advantageous in performing it efficiently.
Moreover, according to this Embodiment, since the regenerative resistor 32 is provided in the vicinity of the 2nd cover side suction inlet 52, the heat radiation of the regenerative resistor 32 is 2nd cover side open | released by air | atmosphere. This is advantageous in efficiently performing in the direction of the suction port 52.
Moreover, according to this Embodiment, since the regenerative resistor 32 is located under the upper partition plate 42, the location where the centrifugal blower 20 is installed is a location where it is exposed to rainwater or dust. However, the upper partition plate 42 is advantageous in protecting the regenerative resistor 32 from rainwater, dust and foreign matter.

  In addition, in this Embodiment, although the case where the centrifugal blower 20 was used for the combustion apparatus 16 of the boiler 10 was demonstrated, the use of the centrifugal blower of this invention is not limited to the combustion apparatus 16 of the boiler 10, Widely used in various applications.

DESCRIPTION OF SYMBOLS 10 ... Boiler 16 ... Combustion device 20 ... Centrifugal blower 22 ... Impeller 24 ... Fan casing 2408 ... Suction port 2410 ... Outlet 26 ... Cover 28 ... Motor 30 ... Inverter 32 ... Regeneration Resistor 42 …… Upper partition plate 44 …… Lower partition plate 48 …… Cover side air guide passage 52 …… Second cover side suction port 56 …… Air filter

Claims (5)

Impeller,
A fan casing that houses the impeller and is provided with an inlet and an outlet;
A motor that rotationally drives the impeller,
A centrifugal blower that sucks air from the suction port by rotation of the impeller and blows out the sucked air from the air outlet,
An inverter for controlling the rotation speed of the motor;
A regenerative resistor connected to the inverter and consuming regenerative power of the motor;
The regenerative resistor is disposed at a location that strikes the flow of air sucked into the suction port,
A centrifugal blower characterized by that. The regenerative resistor has an elongated shape,
The regenerative resistor is arranged with its longitudinal direction orthogonal to the air flow,
The centrifugal blower according to claim 1, wherein: The regenerative resistor is arranged so that the entire surface thereof is in contact with the air flow,
The centrifugal blower according to claim 1 or 2, characterized by the above. The centrifugal blower further includes a cover connected to the fan casing,
The cover includes a cover side air guide passage connected to the suction port, and a cover side air inlet port connected to the cover side air guide passage,
The regenerative resistor is disposed in the cover side air guide path,
The centrifugal blower according to any one of claims 1 to 3, wherein the centrifugal blower is provided. The centrifugal blower is used for supplying air for combustion in a boiler combustion device.
The centrifugal blower according to any one of claims 1 to 4, wherein the centrifugal blower is provided.

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