JP2016180344A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal blower which achieves downsizing of a casing while rectifying suctioned airflow and inhibits deterioration of performance (a static pressure) and increase of suction noise from being caused by turbulence of the suctioned airflow.SOLUTION: A centrifugal blower 1 includes: a casing 2 comprising a scroll 6, a suction side plate 5, and a motor fixing side plate 8; an impeller 3 provided in the casing 2; and a bell-mouth 9 provided at a periphery of an opening part 4 of the suction side plate 5. The impeller 3 is fixed to a motor 7 fixed to the motor fixing side plate 8, and a cylindrical member 10 is connected with the opening part 4 of the suction side plate 5. The bell-mouth 9 has a bending part 14, and the bending part 14 protrudes into the cylindrical member 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a centrifugal blower used for a ventilation blower such as a duct fan, an air conditioner or the like.

  A general centrifugal blower has a bell mouth with a bent portion at the suction port, and the bent portion of the bell mouth rectifies the suction air flow from the suction duct and guides it into the impeller, and the performance of the centrifugal blower The thing which suppressed the fall of (static pressure) and generation | occurrence | production of the suction noise is known.

  The conventional example will be described below with reference to FIG.

  As shown in FIG. 6, the centrifugal blower 101 includes a casing 102 and an impeller 103 built in the casing 102. The casing 102 includes a suction side plate 105 having an opening 104, a spiral scroll 106, and a motor fixed side plate 108 to which a motor 107 is fixed. A bell mouth 109 is provided on the periphery of the opening 104. The bell mouth 109 is fixed between the suction side plate 105 and the suction duct 110. The impeller 103 is fixed to the motor 107, and when the impeller 103 rotates by driving the motor 107, the suction airflow 111 flows into the casing 102 through the suction duct 110 and the bell mouth 109 and through the impeller 103. The air blown out from the impeller 103 is pressurized in the casing 102, converted from dynamic pressure to static pressure, and flows out from the discharge port 112 as a discharge airflow 113.

  Here, the bell mouth 109 has a bent portion 114, and the suction airflow 111 that has passed through the suction duct 110 flows along the bent portion 114, is rectified, and is guided into the impeller 103. That is, the bell mouth 109 suppresses pressure loss and turbulence due to sudden reduction from the suction duct 110. With these configurations, the reduction in performance (static pressure) due to pressure loss of the suction airflow 111 near the suction port 115 of the bell mouth 109 and the generation of suction noise due to turbulence are suppressed.

JP-A-4-350399

  Although such a conventional centrifugal blower 101 can suppress a decrease in performance (static pressure) and generation of suction noise, when trying to obtain a larger rectification effect near the suction port 115, the wind speed of the suction airflow 111 is particularly high. When it is fast, it is necessary to increase the radius of curvature 116 of the bent portion 114. In other words, in order to prevent the suction airflow 111 having a high wind speed from colliding with the bent portion 114 and being separated from the bent portion 114 and being disturbed, it is necessary to increase the curvature radius 116 and to flow along the bent portion 114. . For this reason, there existed a subject that the width dimension 117 of a casing became large.

  Further, since the radius of curvature 116 is increased, the distance between the impeller 103 and the suction side plate 105 is increased, and the airflow 118 in the casing that has flowed out of the impeller 103 into the casing 102 is between the impeller 103 and the suction side plate 105. Had flowed into. That is, a backflow of airflow occurred near the suction port 115. The airflow 111 is disturbed by the airflow, and there is a problem that the performance (static pressure) is reduced and the suction noise is increased.

  In addition, since there is a limit to the space behind the ceiling in equipment installed on the ceiling, a small-diameter connection duct is required to save space. Since the suction duct 110 is connected to the peripheral edge portion 119 on the suction duct 110 side of the curvature radius 116 of the bending portion 114, there is a problem that the diameter of the suction duct 110 increases as the curvature radius 116 increases.

  The present invention solves such a conventional problem, suppresses an increase in the width of the casing, ensures a radius of curvature of the bent portion of the bell mouth, and pressure of the suction airflow in the vicinity of the suction port. It aims at providing the centrifugal blower which suppresses generation | occurrence | production of the suction noise by the fall of the performance (static pressure) by a loss, and disorder.

  In order to achieve the above object, a centrifugal blower according to the present invention includes a casing including a scroll, a suction side plate, and a motor fixing side plate, an impeller provided in the casing, and a peripheral edge of an opening of the suction side plate. A centrifugal blower in which the impeller is fixed to a motor fixed to the motor fixing side plate, and a cylindrical member is connected to the opening of the suction side plate. Has a bent portion, and the bent portion protrudes into the cylindrical member.

  According to the present invention, it is possible to provide a centrifugal blower that can downsize the casing while rectifying the suction airflow, and can suppress a decrease in performance (static pressure) and an increase in suction noise due to the disturbance of the suction airflow.

(A) Side view of the centrifugal blower of Embodiment 1 of this invention, (b) Front sectional drawing Front sectional drawing of the centrifugal blower of Embodiment 2 of this invention Front sectional view of the centrifugal blower of Embodiment 3 of the present invention Front sectional view of a centrifugal fan according to a fourth embodiment of the present invention. (A) Side view, front sectional view of centrifugal fan of embodiment 5 of the present invention (A) Side view of conventional centrifugal blower, (b) Front sectional view

  A centrifugal blower according to the present invention comprises a casing comprising a scroll, a suction side plate, and a motor fixed side plate, an impeller provided in the casing, and a bell mouth provided at the periphery of the opening of the suction side plate. A centrifugal blower in which the impeller is fixed to a motor fixed to the motor fixing side plate, and a cylindrical member is connected to the opening of the suction side plate, wherein the bell mouth has a bending portion, The bent portion protrudes into the cylindrical member, and the radius of curvature of the bent portion of the bell mouth can be increased. Because the radius of curvature of the bent part is large, the suction airflow from the suction duct is prevented from being separated from the bent part and colliding with the bent part, and the suction airflow flows into the impeller while being rectified along the bent part. Will be. Further, by projecting the bent portion toward the cylindrical member, a large radius of curvature of the bent portion can be secured without increasing the width dimension of the casing. That is, a large radius of curvature of the bent portion can be secured without increasing the distance between the impeller and the suction side plate. Thereby, it is possible to prevent the airflow in the casing that has flowed out of the impeller into the casing from flowing between the impeller and the suction side plate. Therefore, it is possible to suppress the disturbance of the suction airflow due to the divergence from the bent portion of the bell mouth, and it is possible to suppress the suction airflow from being disturbed by the airflow in the casing. As a result, the casing can be downsized while rectifying the suction airflow, and a decrease in performance (static pressure) and an increase in suction noise due to the disturbance of the suction airflow can be suppressed.

  The inner diameter of the end of the cylindrical member on the suction side plate side may be larger than the outer diameter of the bell mouth.

  According to this, since the cylindrical member can be formed so as to include the bent portion of the bell mouth, it is possible to secure a large bent portion and to fix the cylindrical member to the suction side plate, not the unstable bent portion of the bell mouth. be able to. As a result, the casing can be downsized while rectifying the suction airflow, and a decrease in performance (static pressure) and an increase in suction noise due to disturbance of the suction airflow can be suppressed. Further, the cylindrical member can be reliably fixed to the casing.

  The cylindrical member may be an adapter, the suction duct and the opening may be connected via the adapter, and the bent portion may be protruded into the adapter.

  According to this, the width dimension of the casing can be reduced while increasing the radius of curvature of the bent portion of the bell mouth. Therefore, it can suppress that the suction airflow from a suction duct collides with a bending part, and is dissociated from a bending part and is disturb | confused, and it can flow in into an impeller while rectifying a suction airflow along a bending part. Moreover, it is possible to prevent the airflow in the casing that has flowed out of the impeller into the casing from flowing between the impeller and the suction side plate. Moreover, the diameter of the suction duct can be reduced by the adapter, and the suction duct can be constructed by being inserted into the adapter. This reduces the size of the casing while rectifying the suction airflow, reduces the performance (static pressure) due to the turbulence of the suction airflow, and suppresses the increase in suction noise, and also reduces the diameter of the suction duct, making the suction duct workable. Can be

  Moreover, you may make the outer periphery of the said bending part contact the inner surface of the said adapter.

  According to this, it can suppress that the suction airflow from a suction duct flows in between the outer periphery of the bending part of a bell mouth, and the inner surface of an adapter, and a suction airflow is disturb | confused. Thereby, the increase in the suction noise due to the disturbance of the suction airflow can be suppressed.

  Moreover, the said bending part is made into the convex shape which protrudes on the opposite side of the said impeller, and the said suction side board may cover the half or more of the space formed inside the said convex shape.

  According to this, it can be made small by interrupting | blocking the space between the impeller and the suction side plate which spread by the convex-shaped space with the suction side plate. Therefore, it is possible to prevent the airflow in the casing that has flowed into the casing from the impeller from flowing between the impeller and the suction side plate. Further, since a part of the space is opened, suction noise can be made incident into the space, thereby forming a resonance-type silenced space. As a result, an increase in suction noise due to disturbance of the suction airflow can be suppressed, and suction noise can be reduced by a resonance effect.

  The bell mouth may include a flange portion on the outer periphery on the cylindrical member side, and the flange portion may be fixed by being sandwiched between the cylindrical member and the suction side plate.

  According to this, while securing the fixed space of the bell mouth, it is possible to secure the bent part up to the part that contacts the inner surface of the adapter, and the radius of curvature can be increased, so the suction airflow from the suction duct collides with the bent part, It is possible to suppress turbulence by being separated from the bent portion, and to flow the suction airflow into the impeller while rectifying the bent airflow along the bent portion. As a result, the casing can be downsized while rectifying the suction airflow, and a decrease in performance (static pressure) and an increase in suction noise due to disturbance of the suction airflow can be suppressed.

  Further, the bell mouth and the suction side plate may be integrally formed.

  According to this, it is possible to reduce the number of parts while suppressing wind leakage at the connecting portion between the bell mouth and the suction side plate when the inside of the casing is at high static pressure. As a result, a decrease in performance (static pressure) due to wind leakage can be suppressed, and the cost can be reduced by reducing the number of parts.

  The scroll includes a discharge port, the center of the adapter viewed from the cylindrical member side is shifted to the discharge port side, and the center of the adapter is centered on the bell mouth opening viewed from the cylindrical member side. It may be shifted.

  According to this, the duct displacement amount between the upper and lower sides of the discharge duct and the suction duct can be reduced or eliminated, so that the duct piping space can be suppressed. As a result, the setting space can be saved and installation in a narrow space becomes possible, and construction can be reduced by equalizing the duct position.

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

(Embodiment 1)
As shown in FIG. 1, the centrifugal blower 1 of the present embodiment includes a casing 2 and an impeller 3. The impeller 3 is built in the casing 2.

  The casing 2 includes a suction side plate 5 having an opening 4, a spiral scroll 6 having a discharge port 12, and a motor fixing side plate 8 to which a motor 7 is fixed.

  A bell mouth 9 is provided at the periphery of the opening 4. The opening by the bell mouth 9 becomes a suction port.

  A cylindrical member 10 is connected to the opening 4 of the suction side plate 5.

  The impeller 3 is fixed to the motor 7. When the impeller 3 is rotated by driving the motor 7, the suction airflow 11 flows from the cylindrical member 10 through the opening (suction port) of the bell mouth 9 into the casing 2 through the impeller 3.

  The air blown out from the impeller 3 is pressurized in the casing 2, converted from dynamic pressure to static pressure, and flows out from the discharge port 12 as a discharge air flow 13.

  The bell mouth 9 has a bent portion 14, and the bent portion 14 is formed so as to protrude into the tubular member 10.

  The inner diameter of the end of the cylindrical member 10 on the suction side plate 5 side is preferably larger than the outer diameter of the bell mouth 9.

  Note that the connection of the tubular member 10 to the opening 4 means that the tubular member 10 is connected so that air from the tubular member 10 flows into the opening 4. In addition to being indirectly connected.

  Moreover, a cylindrical member means an adapter or a suction duct. For example, when an adapter is not provided, the tubular member 10 indicates a suction duct. The cylindrical member 10 (adapter and suction duct) has a round shape, for example.

  The operation and effect of the above configuration will be described.

  By forming the bent portion 14 so as to protrude toward the cylindrical member 10, the radius of curvature 15 of the bent portion 14 of the bell mouth 9 can be increased.

  For this reason, the suction airflow 11 flowing through the cylindrical member 10 is prevented from being disturbed by being separated from the bending portion 14 by colliding with the bending portion 14, and flows into the impeller 3 while being rectified along the bending portion 14. It will be.

  In addition, a large radius of curvature 15 of the bent portion 14 can be secured without increasing the width dimension 16 of the casing 2. That is, a large radius of curvature 15 of the bent portion 14 can be secured without increasing the distance between the impeller 3 and the suction side plate 5.

  Since the distance between the impeller 3 and the suction side plate 5 does not increase, it is possible to prevent the in-casing airflow 17 flowing out from the impeller 3 into the casing 2 from flowing between the impeller 3 and the suction side plate 5. Therefore, the turbulence of the suction airflow 11 due to the deviation from the bent portion 14 of the bell mouth 9 can be suppressed, and the turbulence of the suction airflow 11 by the in-casing airflow 17 can be suppressed.

  Moreover, the cylindrical member 10 can be formed so as to include the bent portion 14 of the bell mouth 9 by making the inner diameter of the end portion on the suction side plate 5 side of the cylindrical member 10 larger than the outer diameter of the bell mouth 9. . For this reason, the bent portion 14 can be secured large, and the tubular member 10 can be fixed to the suction side plate 5 instead of the unstable bent portion 14 of the bell mouth 9.

  As described above, according to the centrifugal blower of the first embodiment of the present invention, the casing 2 is reduced in size while the suction airflow 11 is rectified, and the performance (static pressure) is reduced and the suction noise is increased due to the disturbance of the suction airflow 11. Can be suppressed. It is also possible to securely fix the tubular member 10 to the casing 2.

(Embodiment 2)
A centrifugal blower according to a second embodiment of the present invention will be described with reference to FIG. About the same structure as 1st Embodiment, the same number is attached | subjected and detailed description is abbreviate | omitted.

  In the centrifugal blower 1 shown in FIG. 2, the tubular member 10 is an adapter 18, and the suction duct 19 and the opening 4 are connected via the adapter 18.

  The bent portion 14 of the bell mouth 9 projects into the adapter 18. Further, it is preferable that the outer periphery of the bent portion 14 is brought into contact with the inner surface of the adapter 18.

  The adapter 18 preferably has a shape in which the diameter is sequentially reduced from the suction side plate 5 toward the suction duct 19.

  The diameter of the adapter 18 on the suction duct 19 side is preferably the same as the apex of the bent part 14 of the bell mouth 9 on the suction duct 19 side.

  The bent portion 14 has a convex shape protruding to the opposite side of the impeller 3, and preferably has a structure in which the suction side plate 5 covers more than half of the space 20 formed inside the convex shape.

  The operation and effect of the above configuration will be described.

  The width dimension 16 of the casing 2 can be reduced while increasing the curvature radius 15 of the bent portion 14 of the bell mouth 9. Therefore, the suction air flow 11 from the suction duct 19 is prevented from being separated from the bending portion 14 and disturbed by colliding with the bending portion 14, and flows into the impeller 3 while rectifying the suction air flow 11 along the bending portion 14. Can be made.

  Further, since the distance between the impeller 3 and the suction side plate 5 does not increase, it is possible to prevent the airflow 17 in the casing that has flowed out of the impeller 3 into the casing 2 from flowing between the impeller 3 and the suction side plate 5. it can.

  When the bent portion 14 of the bell mouth 9 is protruded toward the suction duct 19 without the adapter 18, the diameter of the suction duct 19 is increased by the amount of the bent portion 14.

  In the present embodiment, since there is an adapter 18 that gradually reduces the diameter from the suction side plate 5 toward the suction duct 19, the diameter of the suction duct 19 can be reduced, and the suction duct 19 can be constructed by being inserted into the adapter 18. It becomes.

  Further, by bringing the outer periphery of the bent portion 14 into contact with the inner surface of the adapter 18, the suction air flow 11 from the suction duct 19 flows in between the outer periphery of the bent portion 14 of the bell mouth 9 and the inner surface of the adapter 18. Disturbance of the airflow 11 can be suppressed.

  Moreover, it is preferable that the suction side plate 5 covers more than half of the space 20. Thereby, the space between the impeller 3 and the suction side plate 5 spread by the convex space 20 can be reduced by partially blocking the suction side plate 5. Therefore, it is possible to prevent the airflow 17 in the casing that has flowed out of the impeller 3 into the casing 2 from flowing between the impeller 3 and the suction side plate 5. Further, when a part of the space 20 is opened to the casing side, suction noise can be made incident into the space 20 to form a resonance-type silenced space.

  As described above, according to the centrifugal blower of the second embodiment of the present invention, the casing 2 is downsized while the suction airflow 11 is rectified, and the performance (static pressure) is reduced and the suction noise is increased due to the disturbance of the suction airflow 11. The suction duct 19 can be reduced in diameter and the workability of the suction duct 19 can be improved. Further, the suction noise can be reduced by the resonance effect by the space 20 of the bent portion 14 of the bell mouth 9. Although the bell mouth 9 is fixed to the suction side plate 5 in the present embodiment, the effect is the same even if it is fixed to the cylindrical member 10 (the adapter 18 or the suction duct 19).

(Embodiment 3)
A centrifugal blower according to a third embodiment of the present invention will be described with reference to FIG. The same configurations as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  The centrifugal blower 1 shown in FIG. 3 includes a flange portion 21 on the outer periphery of the bell mouth 9 on the cylindrical member 10 side. The bell mouth 9 is fixed by sandwiching the flange portion 21 between the tubular member 10 and the suction side plate 5.

  The operation and effect of the above configuration will be described.

  While securing the fixing space for the bell mouth 9, the bent portion 14 can be secured up to the portion contacting the inner surface of the adapter 18, and the radius of curvature 15 can be further increased. As a result, the suction air flow 11 from the suction duct 19 is prevented from being disturbed by being separated from the bending portion 14 by colliding with the bending portion 14, and the suction air flow 11 is rectified along the bending portion 14 while being rectified in the impeller 3. Can flow in.

  As described above, according to the centrifugal blower of the third embodiment of the present invention, the casing 2 is downsized while the suction airflow 11 is rectified, and the performance (static pressure) is reduced and the suction noise is increased due to the disturbance of the suction airflow 11. Can be suppressed.

(Embodiment 4)
A centrifugal blower according to a fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  The centrifugal blower 1 shown in FIG. 4 has the bell mouth 9 and the suction side plate 5 integrated and bent to form a bent portion 22.

  The bent mouth 22 makes the bell mouth 9 and the suction side plate 5 continuous parts, and the gap can be eliminated, so that the airflow is prevented from leaking from the casing 2 and can be kept in the casing 2.

  In the present embodiment, the connecting portion between the bell mouth 9 and the suction side plate 5 is formed by the bent portion 22, and the bent portion 22 covers more than half of the space 20, but the space 20 is bent. Even in the structure not covered by the portion 22, the effect on the airflow leakage is the same.

  The operation and effect of the above configuration will be described.

  The number of parts can be reduced while suppressing the wind leakage at the connecting portion between the bell mouth 9 and the suction side plate 5 when the inside of the casing 2 is at a high static pressure.

  Thus, according to the centrifugal blower of Embodiment 4 of this invention, the fall of the performance (static pressure) by a wind leak can be suppressed, and cost reduction by the number of parts reduction can also be performed.

(Embodiment 5)
A centrifugal blower according to a fifth embodiment of the present invention will be described with reference to FIG. The same components as those in the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  The centrifugal blower 1 shown in FIG. 5 shifts the adapter center line 23 of the adapter 18 viewed from the cylindrical member 10 side to the discharge port center line 26 side of the discharge port 12 viewed from the discharge duct 25 side. It is formed so as to be shifted from the bell mouth opening center line 24 of the bell mouth 9 as viewed from the cylindrical member 10 side.

  Specifically, in FIG. 5, for example, the upper center space 27 of the bent portion 14 of the bell mouth 9 is increased in the vertical direction, and the lower space 28 of the bent portion 14 is decreased in the vertical direction. Is moved upward in FIG.

  In the present embodiment, the adapter center line 23 and the discharge port center line 26 are shifted in the vertical direction of the drawing for easy understanding of the structure. However, the vertical height between the adapter center line 23 and the discharge port center line 26 is vertical. It is also possible to make the adapter 18 and the discharge duct 25 at the same position level in the vertical direction of the drawing.

  The operation and effect of the above configuration will be described.

  The amount of displacement between the upper and lower ducts of the discharge duct 25 and the suction duct 19 can be reduced or eliminated. Thereby, the duct piping space at the time of construction can be suppressed.

  As described above, according to the centrifugal blower of the fifth embodiment of the present invention, the equipment setting space can be saved and can be installed in a narrow space, and the construction can be saved by the same level of duct position (positioning is not required). , Suspension bolts have the same length, etc.).

  In addition, according to Embodiment 1-5, it is also possible to obtain the centrifugal blower 1 which suppressed the backflow of the airflow in the casing 2, and made the suction duct small-diameter.

  In addition to the purpose of air conveyance such as ventilation blower equipment, the present invention can also be applied to the use of air blowing of equipment equipment that can cool equipment equipment using air blown from the air outlet.

DESCRIPTION OF SYMBOLS 1 Centrifugal blower 2 Casing 3 Impeller 4 Opening part 5 Suction side plate 6 Scroll 7 Motor 8 Motor fixed side plate 9 Bell mouth 10 Cylindrical member 11 Suction air flow 12 Discharge port 13 Discharge air flow 14 Bending part 15 Curvature radius 16 Width dimension 17 In casing Airflow 18 Adapter 19 Suction duct 20 Space 21 Flange part 22 Bending part 23 Adapter center line 24 Bell mouth opening center line 25 Discharge duct 26 Discharge port center line 27 Upper space 28 Lower space

Claims (8)

A casing composed of a scroll, a suction side plate, and a motor fixed side plate;
An impeller provided in the casing;
A bell mouth provided at the periphery of the opening of the suction side plate;
Fixing the impeller to a motor fixed to the motor fixing side plate;
A centrifugal blower in which a cylindrical member is connected to the opening of the suction side plate,
The bell mouth has a bent part,
A centrifugal blower characterized in that the bent portion protrudes into the cylindrical member. The centrifugal blower according to claim 1, wherein an inner diameter of an end portion of the cylindrical member on the suction side plate side is larger than an outer diameter of the bell mouth. The cylindrical member is an adapter;
Connect the suction duct and the opening through the adapter,
The centrifugal blower according to claim 1 or 2, wherein the bent portion protrudes into the adapter. The centrifugal blower according to claim 3, wherein an outer periphery of the bent portion is brought into contact with an inner surface of the adapter. The bent portion has a convex shape protruding to the opposite side of the impeller,
The centrifugal blower according to any one of claims 1 to 4, wherein the suction side plate covers half or more of a space formed inside the convex shape. The bell mouth includes a flange portion on the outer periphery on the cylindrical member side,
The centrifugal blower according to any one of claims 1 to 5, wherein the flange portion is sandwiched and fixed between a cylindrical member and the suction side plate. The centrifugal blower according to any one of claims 1 to 5, wherein the bell mouth and the suction side plate are integrally formed. The scroll includes a discharge port,
Shift the center of the adapter viewed from the cylindrical member side to the discharge port side,
The centrifugal blower according to any one of claims 1 to 7, wherein a center of the adapter is shifted from an opening center of the bell mouth viewed from the cylindrical member side.

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