Centrifugal blower and air-conditioning device comprising same

Abstract

This centrifugal blower comprises an impeller having a disk-shaped main plate, a plurality of vanes arranged in a circumferential direction on a peripheral edge part of the main plate, and an annular side plate which is disposed facing the main plate and fixes the plurality of vanes. An impeller suction port is provided on the side plate side of the impeller. Each of the plurality of vanes is provided with at least one guide provided on a negative pressure surface and facing the side plate. The at least one guide is provided at a position closer to the side plate than to the main plate, and is curved so that the shape in the direction along the negative pressure surface is convex and so that the inner peripheral end is curved toward the impeller suction port.

Description

Centrifugal blower and air conditioner equipped with the same

[0001] The present disclosure relates to a centrifugal blower and an air conditioner equipped with the same.

[0002] Conventionally, there is a centrifugal blower including a main board and a side board arranged at intervals in the direction of the rotation axis, and a plurality of blades arranged in the circumferential direction between the main board and the side board. When such a centrifugal blower turns the airflow sucked in the direction of the rotation axis by 90 degrees and discharges it in the radial direction, the airflow tends to deviate toward the main board side due to inertial force, and the airflow tends to separate on the side board side, resulting in a non-uniform blown air velocity distribution.

[0003] Therefore, there is a centrifugal blower with an improved non-uniform blown air velocity distribution (see, for example, Patent Document 1). The centrifugal blower of Patent Document 1 increases the air velocity on the side board side where the air velocity tends to be low by providing a partition plate that divides the air passage between the main board and the side board substantially parallel to the side board, thereby improving the non-uniform blown air velocity distribution.

[0004] Japanese Patent Application Laid-Open No. 2001-082384

[0005] However, in the centrifugal blower of Patent Document 1, although the air velocity on the side board side can be increased by adding the partition plate, on the positive pressure surface side facing the rotation direction side of the blade, the flow is more likely to follow the blade even on the side board side compared to the negative pressure surface side on the opposite side. Therefore, there is a problem that the effect of increasing the air velocity by adding the partition plate is small, and the power consumption increases due to the increase in the ventilation resistance of the partition plate itself.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide a centrifugal blower and an air conditioner equipped with the same that can improve the non-uniform blown air velocity distribution and improve the power consumption.

[0007] The centrifugal blower according to this disclosure comprises an impeller having a disc-shaped main plate, a plurality of blades arranged circumferentially on the peripheral edge of the main plate, and an annular side plate positioned opposite the main plate and fixing the plurality of blades, wherein an impeller intake port is provided on the side plate side of the impeller, and each of the plurality of blades is provided on a negative pressure surface and has at least one guide opposite the side plate, the at least one guide is provided closer to the side plate than the main plate, and is curved such that its shape in the direction along the negative pressure surface is convex toward the main plate, and its inner circumferential end is curved toward the impeller intake port.

[0008] Furthermore, the air conditioning system relating to this disclosure is equipped with the centrifugal blower described above.

[0009] According to this disclosure, by providing guides on the negative pressure surfaces of multiple blades, the airflow flowing in from the rotation axis direction is more easily redirected radially, suppressing airflow separation on the negative pressure surfaces of the blades and reducing the likelihood of airflow bias toward the main plate. As a result, the uneven distribution of discharged air velocity can be improved. Furthermore, by providing the guides only at positions close to the side plates of the negative pressure surfaces of blades with low discharged air velocity, the increase in airflow resistance due to the guides can be suppressed. As a result, power consumption can be improved.

[0010] This is a schematic perspective view showing the configuration of the impeller of a centrifugal blower according to Embodiment 1. This is a schematic plan view showing the configuration of the impeller of a centrifugal blower according to Embodiment 1. This is a schematic perspective view showing a partially enlarged portion of the impeller of a centrifugal blower according to Embodiment 1. This is a schematic side view of the A-A cross section in Figure 2, viewed in the direction of the arrow. This is a schematic side view showing a part of the centrifugal blower according to Embodiment 1. This is a schematic side view showing a cross-section of a part of the impeller of a centrifugal blower according to Embodiment 2. This is a schematic side view showing a cross-section of a part of the impeller of a centrifugal blower according to Embodiment 3. This is a schematic side view showing a cross-section of a part of the impeller of a centrifugal blower according to Embodiment 4. This is a schematic side view showing a cross-section of a part of the impeller of a centrifugal blower according to Embodiment 5. This is a schematic side view showing a cross-section of a part of the impeller of a centrifugal blower according to Embodiment 6. This is a schematic perspective view showing the configuration of the impeller of a centrifugal blower according to Embodiment 7. This is a schematic plan view showing the configuration of the impeller of a centrifugal blower according to Embodiment 7. This is a schematic side view of the B-B cross-section in Figure 12, viewed in the direction of the arrow. This figure shows an example of the configuration of an air conditioning system according to Embodiment 8.

[0011] The embodiments of this disclosure will be described below with reference to the drawings. Note that the configurations shown in the full text of the specification are merely examples and are not limited to those described in the specification. In particular, the combinations of components are not limited to those in each embodiment; components described in other embodiments can be applied to other embodiments. Also, the size relationships of the components in the following drawings may differ from those in reality.

[0012] Furthermore, in the following explanation, terms indicating direction, such as "up," "down," "right," "left," "front," and "back," will be used as appropriate to facilitate understanding. These terms are for illustrative purposes only and do not limit the embodiments. In the embodiments, "up," "down," "right," "left," "front," and "back" are used when viewing the centrifugal blower from the front.

[0013] Embodiment 1. Figure 1 is a schematic perspective view showing the configuration of the impeller 10 of the centrifugal blower 1 according to Embodiment 1. Figure 2 is a schematic plan view showing the configuration of the impeller 10 of the centrifugal blower 1 according to Embodiment 1. Figure 3 is a schematic perspective view showing a partially enlarged portion of the impeller 10 of the centrifugal blower 1 according to Embodiment 1. Figure 4 is a schematic side view of the A-A cross section in Figure 2, viewed in the direction of the arrow. Figure 5 is a schematic side view showing a part of the centrifugal blower 1 according to Embodiment 1.

[0014] The centrifugal blower 1 according to Embodiment 1 is a multi-blade centrifugal blower and has an impeller 10 that generates airflow. As shown in Figures 1 and 2, the impeller 10 has a disc-shaped main plate 11, a plurality of blades 12 of uniform thickness, and an annular side plate 13. The main plate 11 is provided with a shaft portion 11b to which a motor (not shown) is connected. The plurality of blades 12 are arranged circumferentially on the periphery of the main plate 11. The side plate 13 is positioned opposite the main plate 11 and fixes the plurality of blades 12.

[0015] As shown in Figures 2 and 3, the impeller 10 is a centrifugal impeller. The impeller 10 is made of metal, for example, multiple steel plates. The impeller 10 is rotationally driven by a motor or the like (not shown), and is configured to forcibly send air outwards in the centrifugal direction, i.e., radially outwards, by the centrifugal force generated by the rotation, and to draw air in through the impeller intake port 10a provided on the side plate 13. The impeller 10 rotates in the rotational direction R by the motor or the like.

[0016] The thickness of the main plate 11 may be formed as a disc shape in which the thickness of the walls increases toward the center in the radial direction centered on the rotation axis RS, or it may be formed to a constant thickness in the radial direction centered on the rotation axis RS. The main plate 11 may be plate-shaped, and its shape may be other than circular, such as a polygon. A motor (not shown) is connected to a shaft portion 11b provided in the center of the main plate 11, and the main plate 11 is rotated by the motor via the shaft portion 11b.

[0017] Multiple blades 12 are arranged circumferentially on the surface of the main plate 11 with respect to a rotation axis RS, forming a predetermined spacing between adjacent blades 12. The multiple blades 12 arranged on the main plate 11 give the impeller 10 a cylindrical shape. The gaps formed between adjacent blades 12 constitute the flow passage 11a of the impeller 10.

[0018] As shown in Figures 1 to 4, each of the multiple radially arranged blades 12 is provided with a guide 14 extending in the circumferential direction. As shown in Figure 4, the guide 14 is provided on the negative pressure surface 12b of the blade 12 so as to face the side plate 13. The guide 14 is also provided closer to the side plate 13 than to the main plate 11. The guide 14 has a rib shape that protrudes from the negative pressure surface 12b of the blade 12 in the axial direction of the rotation axis RS. As shown in Figures 1 and 3, the guide 14 has a curved shape such that the shape in the direction along the negative pressure surface 12b of the blade 12 is convex toward the main plate 11, and the inner circumferential end 14i is curved toward the impeller intake port 10a. As shown in Figure 5, the inner circumferential end 14i of the guide 14 is located on the inner side (rotation axis RS side) of the downstream end 26d of the bell mouth 26.

[0019] In this way, by providing guides 14 on the negative pressure surfaces 12b of each of the multiple blades 12, the airflow flowing in from the rotation axis RS direction is more easily redirected radially, suppressing airflow separation on the negative pressure surfaces 12b of the blades 12 and making it less likely for airflow to be biased toward the main plate 11. As a result, the uneven distribution of discharged air velocity can be improved. Furthermore, by providing the guides 14 only at positions close to the side plates 13 on the negative pressure surfaces 12b of the blades 12 with low discharged air velocity, the increase in airflow resistance due to the guides 14 can be suppressed. As a result, power consumption can be improved. In addition, when providing the guides 14, by making only a portion of the negative pressure surface 12b of the blade 12 close to the side plates 13 protrude, a wider distance between blades can be secured on the main plate 11 side than the guides 14, that is, a wider air passage below the guides 14 can be secured, so pressure loss can be reduced by lowering the air velocity. Furthermore, by positioning the inner end 14i of the guide 14 on the inner side of the downstream end 26d of the bell mouth 26, the airflow bias toward the main plate 11 becomes even less likely, and the increase in ventilation resistance due to the guide 14 can be further suppressed.

[0020] As described above, the centrifugal blower 1 according to Embodiment 1 comprises an impeller 10 having a disc-shaped main plate 11, a plurality of blades 12 arranged circumferentially on the peripheral edge of the main plate 11, and an annular side plate 13 positioned opposite the main plate 11 and fixing the plurality of blades 12. An impeller intake port 10a is provided on the side plate 13 side of the impeller 10, and each of the plurality of blades 12 is provided on a negative pressure surface 12b and has at least one guide 14 facing the side plate 13. The at least one guide 14 is provided closer to the side plate 13 than to the main plate 11, and its shape in the direction along the negative pressure surface 12b is curved so as to be convex toward the main plate 11, and its inner circumferential end 14i is curved toward the impeller intake port 10a.

[0021] According to the centrifugal blower 1 of Embodiment 1, by providing guides 14 on the negative pressure surfaces 12b of each of the multiple blades 12, the airflow flowing in from the rotation axis RS direction is more easily redirected radially, suppressing airflow separation on the negative pressure surfaces 12b of the blades 12, and making it less likely for airflow to be biased toward the main plate 11. As a result, the uneven distribution of discharged air velocity can be improved. Furthermore, by providing the guides 14 only at positions close to the side plates 13 on the negative pressure surfaces 12b of blades 12 with low discharged air velocity, the increase in airflow resistance due to the guides 14 can be suppressed. As a result, power consumption can be improved.

[0022] Furthermore, in the centrifugal blower 1 according to Embodiment 1, at least one guide 14 has a rib shape that protrudes from the negative pressure surface 12b.

[0023] According to the centrifugal blower 1 of Embodiment 1, when providing the guide 14, by making only a portion of the negative pressure surface 12b of the blade 12 that is close to the side plate 13 protrude, a wider distance between blades can be secured on the main plate 11 side than the guide 14. In other words, a wider air passage below the guide 14 can be secured, so pressure loss can be reduced by lowering the air velocity.

[0024] Furthermore, the centrifugal blower 1 according to Embodiment 1 has a bell mouth 26, and the inner circumferential end 14i of at least one guide 14 is located on the inner side of the downstream end 26d of the bell mouth 26.

[0025] According to the centrifugal blower 1 of Embodiment 1, by positioning the inner circumferential end 14i of the guide 14 on the inner side of the downstream end 26d of the bell mouth 26, the bias of the airflow toward the main plate 11 becomes even less likely, and the increase in airflow resistance due to the guide 14 can be further suppressed.

[0026] Embodiment 2. Embodiment 2 will be described below, but the description of parts that overlap with Embodiment 1 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to those in Embodiment 1.

[0027] Figure 6 is a schematic side view showing a cross-section of a part of the impeller 10 of the centrifugal blower 1 according to Embodiment 2. Note that Figure 6 is a view of the same cross-section as Figure 4 according to Embodiment 1, but in the same direction. As shown in Figure 6, the guide 14 according to Embodiment 2 is provided on the negative pressure surface 12b of the blade 12 so as to face the side plate 13. The guide 14 is also provided closer to the side plate 13 than to the main plate 11. The guide 14 is formed by a part of the negative pressure surface 12b of the blade 12 being recessed toward the positive pressure surface 12a, and the blade 12 has different thicknesses on either side of the guide 14. The guide 14 has a curved shape such that the shape in the direction along the negative pressure surface 12b of the blade 12 is convex toward the main plate 11, and the inner circumference end 14i is curved toward the impeller intake port 10a. In this way, by providing the guide 14 according to Embodiment 2 on each of the negative pressure surfaces 12b of multiple blades 12, the same effects as in Embodiment 1 can be obtained.

[0028] In the centrifugal blower 1 according to Embodiment 2, at least one guide 14 is formed by a part of the negative pressure surface 12b being recessed toward the positive pressure surface 12a.

[0029] According to the centrifugal blower 1 of Embodiment 2, by providing guides 14 on the negative pressure surfaces 12b of each of the multiple blades 12, the airflow flowing in from the rotation axis RS direction is more easily redirected radially, suppressing airflow separation on the negative pressure surfaces 12b of the blades 12, and making it less likely for airflow to be biased toward the main plate 11. As a result, the uneven distribution of discharged air velocity can be improved. Furthermore, by providing the guides 14 only at positions close to the side plates 13 on the negative pressure surfaces 12b of blades 12 with low discharged air velocity, the increase in airflow resistance due to the guides 14 can be suppressed. As a result, power consumption can be improved.

[0030] Embodiment 3. Embodiment 3 will be described below, but the description of parts that overlap with Embodiments 1 and 2 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 and 2.

[0031] Figure 7 is a schematic side view showing a cross-section of a part of the impeller 10 of the centrifugal blower 1 according to Embodiment 3. Note that Figure 7 is a view of the same cross-section as Figure 4 according to Embodiment 1, but in the same direction. As shown in Figure 7, the guide 14 according to Embodiment 3 is provided on the negative pressure surface 12b of the blade 12 so as to face the side plate 13. The guide 14 is also provided closer to the side plate 13 than to the main plate 11. In addition, there are multiple guides 14 (two in Embodiment 3), each formed by a recess in a part of the negative pressure surface 12b of the blade 12. The multiple guides 14 are stepped, and the blade 12 has different thicknesses on each side of the guide 14. The multiple guides 14 each have a curved shape that protrudes toward the main plate 11, and their inner circumference ends 14i curve toward the impeller intake port 10a. In this way, by providing multiple guides 14 according to Embodiment 3 on the negative pressure surface 12b of each of the multiple blades 12, the same effects as in Embodiment 1 can be obtained.

[0032] In the centrifugal blower 1 according to Embodiment 3, at least one of the guides 14 is a plurality of guides and is stepped in shape.

[0033] According to the centrifugal blower 1 of Embodiment 3, by providing multiple guides 14 on the negative pressure surfaces 12b of each of the multiple blades 12, the airflow flowing in from the rotation axis RS direction is more easily redirected radially, suppressing airflow separation on the negative pressure surfaces 12b of the blades 12, and making it less likely for airflow to be biased toward the main plate 11. As a result, the uneven distribution of discharged air velocity can be improved. Furthermore, by providing the multiple guides 14 only at positions close to the side plates 13 on the negative pressure surfaces 12b of the blades 12 with low discharged air velocity, the increase in airflow resistance due to the multiple guides 14 can be suppressed. As a result, power consumption can be improved.

[0034] Embodiment 4. Embodiment 4 will be described below, but the description of parts that overlap with Embodiments 1 to 3 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 3.

[0035] Figure 8 is a schematic side view showing a cross-section of a part of the impeller 10 of the centrifugal blower 1 according to Embodiment 4. Note that Figure 8 is a view of the same cross-section as Figure 4 according to Embodiment 1, but in the same direction. As shown in Figure 8, the guide 14 according to Embodiment 4 is provided on the negative pressure surface 12b of the blade 12 so as to face the side plate 13. The guide 14 is also provided closer to the side plate 13 than to the main plate 11. The guide 14 has a rib shape that protrudes from the negative pressure surface 12b of the blade 12 in the axial direction of the rotation axis RS. The guide 14 has a curved shape such that the shape in the direction along the negative pressure surface 12b of the blade 12 is convex toward the main plate 11, and the inner circumference end 14i is curved toward the impeller intake port 10a. The guide 14 also has a shape in which the protruding width gradually decreases toward the main plate 11. In this way, by giving the guide 14 a shape in which the protruding width gradually decreases as it approaches the main plate 11, even if there is airflow that goes over the guide 14, the airflow will follow the guide 14, thus further suppressing separation.

[0036] In the centrifugal blower 1 according to Embodiment 4, at least one guide 14 has a shape in which the protruding width gradually decreases as it approaches the main plate 11.

[0037] According to the centrifugal blower 1 of Embodiment 4, by making the guide 14 a shape in which the protruding width gradually decreases as it approaches the main plate 11, even if there is airflow that goes over the guide 14, the airflow will follow the guide 14, thereby further suppressing separation.

[0038] Embodiment 5. Embodiment 5 will be described below, but the description of parts that overlap with Embodiments 1 to 4 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 4.

[0039] Figure 9 is a schematic side view showing a cross-section of a part of the impeller 10 of the centrifugal blower 1 according to Embodiment 5. Note that Figure 9 is a view of the same cross-section as Figure 4 according to Embodiment 1, but in the same direction. As shown in Figure 9, in Embodiment 5, the multiple blades 12 are each composed of a combination of separate positive pressure surfaces 12a and negative pressure surfaces 12b, and are hollow. The guide 14 is integrally formed with the negative pressure surface 12b. By integrally forming the guide 14 with the negative pressure surface 12b in this way, the increase in the number of parts can be suppressed.

[0040] In the centrifugal blower 1 according to Embodiment 5, each of the multiple blades 12 is hollow, formed by combining a separate positive pressure surface 12a and a negative pressure surface 12b, and at least one guide 14 is integrally formed with the negative pressure surface 12b.

[0041] According to the centrifugal blower 1 of Embodiment 5, the guide 14 is integrally formed with the negative pressure surface 12b, thereby suppressing an increase in the number of parts.

[0042] Embodiment 6. Embodiment 6 will be described below, but the description of parts that overlap with Embodiments 1 to 5 will be omitted, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 5.

[0043] FIG. 10 is a schematic side view showing a partial cross section of the impeller 10 of the centrifugal blower 1 according to Embodiment 6. Note that FIG. 10 is a view of the same cross section as FIG. 4 according to Embodiment 1, seen in the same direction. As shown in FIG. 10, the guide 14 according to Embodiment 6 is provided on the negative pressure surface 12b of the blade 12 so as to face the side plate 13. Further, the guide 14 is provided at a position closer to the side plate 13 than the main plate 11. Further, the guide 14 has a rib shape protruding in the axial direction of the rotation axis RS from the negative pressure surface 12b of the blade 12. Further, the guide 14 has a shape curved so that the shape in the direction along the negative pressure surface 12b of the blade 12 is convex toward the main plate 11 side, and the inner peripheral end 14i is curved toward the impeller suction port 10a. Further, a plurality (two in Embodiment 6) of guides 14 are provided at intervals in the direction of the rotation axis RS. Further, the plurality of guides 14 have different protruding widths. By providing a plurality of guides 14 with different protruding widths at intervals in the direction of the rotation axis RS in this way, the airflow that has overcome the guide 14 can be further induced in the radial direction. Also, by providing a plurality at intervals in the direction of the rotation axis RS, it is possible to suppress an increase in the ventilation resistance against the main flow away from the vicinity of the blade 12 while suppressing the protruding width of the guide 14. Also, by making the protruding width of the guide 14 closest to the side plate 13 the largest among the plurality of guides 14, the airflow in the vicinity of the side plate 13 where the flow in the direction of the rotation axis RS is the strongest can be induced in the radial direction.

[0044] As described above, in the centrifugal blower 1 according to Embodiment 6, at least one guide 14 is plural, and each has a different protruding width.

[0045] According to the centrifugal blower 1 according to Embodiment 6, by providing a plurality of guides 14 with different protruding widths at intervals in the direction of the rotation axis RS, the airflow that has overcome the guide 14 can be further induced in the radial direction. Also, by providing a plurality at intervals in the direction of the rotation axis RS, it is possible to suppress an increase in the ventilation resistance against the main flow away from the vicinity of the blade 12 while suppressing the protruding width of the guide 14.

[0046] Also, in the centrifugal blower 1 according to Embodiment 6, the guide 14 closest to the side plate 13 has the largest protruding width among the plurality of guides 14.

[0047] According to the centrifugal blower 1 according to the sixth embodiment, among the plurality of guides 14, by making the protruding width of the guide 14 closest to the side plate 13 the largest, the airflow in the vicinity of the side plate 13 where the flow in the direction of the rotation axis RS is the strongest can be induced in the radial direction.

[0048] Embodiment 7. Hereinafter, Embodiment 7 will be described. However, descriptions of the parts overlapping with Embodiments 1 to 6 will be omitted, and the same reference numerals will be given to the same parts or corresponding parts as those in Embodiments 1 to 6.

[0049] FIG. 11 is a perspective view schematically showing the configuration of the impeller 10 of the centrifugal blower 1 according to the seventh embodiment. FIG. 12 is a plan view schematically showing the configuration of the impeller 10 of the centrifugal blower 1 according to the seventh embodiment. FIG. 13 is a schematic side view of the B - B cross section of FIG. 12 as viewed in the arrow direction.

[0050] As shown in FIGS. 11 to 13, in the seventh embodiment, the side plate 13 includes a vertical portion 13c parallel to the rotation axis RS on the negative pressure surface 12b side of the blade 12. Further, the side plate 13 has a curved shape that bulges toward the main plate 11 side, and the negative pressure surface side portion 13b, which is the portion on the negative pressure surface 12b side of the blade 12, has a larger curvature than the positive pressure surface side portion 13a, which is the portion on the positive pressure surface 12a side of the blade 12. Also, the inner peripheral end 13i and the outer peripheral end 13o of the side plate 13 are provided at a uniform height in the circumferential direction. Further, between adjacent blades 12, the surface between the inner peripheral end 13i and the outer peripheral end 13o of the side plate 13 continuously changes in the circumferential direction.

[0051] Thus, the side plate 13 has a curved shape that is convex toward the main plate 11, and the negative pressure side portion 13b has a greater curvature than the positive pressure side portion 13a. As a result, the airflow flowing in from the rotation axis RS direction tends to become a gentler flow near the side plate 13, and the flow redirected by the guide 14 tends to follow the side plate 13 more easily, suppressing airflow separation at the negative pressure surface 12b of the blade 12. In addition, since the inner circumferential end 13i and outer circumferential end 13o of the side plate 13 are provided at a uniform height in the circumferential direction, the airflow does not tend to fluctuate in the rotation axis RS direction when the impeller 10 is driven to rotate, suppressing noise deterioration due to fluctuations. Furthermore, between adjacent blades 12, the surface between the inner circumferential end 13i and the outer circumferential end 13o of the side plate 13 changes continuously in the circumferential direction, preventing abrupt changes in flow path height and suppressing airflow separation at the side plate 13.

[0052] In the centrifugal blower 1 according to Embodiment 7, the side plate 13 has a curved shape that is convex toward the main plate 11, and the negative pressure side portion 13b, which is the portion on the negative pressure surface 12b side, has a greater curvature than the positive pressure side portion 13a, which is the portion on the positive pressure surface 12a side.

[0053] According to the centrifugal blower 1 of Embodiment 7, the side plate 13 has a curved shape that is convex toward the main plate 11, and the negative pressure side portion 13b has a greater curvature than the positive pressure side portion 13a. As a result, the airflow flowing in from the rotation axis RS direction tends to become a gentler flow near the side plate 13, and the flow redirected by the guide 14 tends to follow the side plate 13 more easily, thereby suppressing airflow separation at the negative pressure surface 12b of the blade 12.

[0054] Embodiment 8. Embodiment 8 will be described below, but the description will be omitted for parts that overlap with Embodiments 1 to 7, and the same reference numerals will be used for parts that are the same as or corresponding to Embodiments 1 to 7.

[0055] Figure 14 shows an example of the configuration of the air conditioning system 500 according to Embodiment 8. In this embodiment, a centrifugal blower 1 is used as the indoor blower 202 of the air conditioning system 500 according to Embodiment 8.

[0056] The air conditioning system 500 according to Embodiment 8 provides air conditioning by heating or cooling a room by transferring heat between the outside air and the indoor air via a refrigerant. The air conditioning system 500 has an outdoor unit 100 and an indoor unit 200. The outdoor unit 100 and the indoor unit 200 are connected by gas refrigerant piping 300 and liquid refrigerant piping 400. The indoor unit 200 has an indoor heat exchanger 201 and an indoor blower 202. The outdoor unit 100 also has a compressor 101, a flow path switching device 102, an outdoor heat exchanger 103, an outdoor blower 104, and a throttling device 105. Furthermore, this air conditioning system 500 is equipped with a refrigerant circuit through which the refrigerant circulates, with the compressor 101, flow path switching device 102, outdoor heat exchanger 103, throttle device 105, and indoor heat exchanger 201 being sequentially connected by refrigerant piping including gas refrigerant piping 300 and liquid refrigerant piping 400.

[0057] The compressor 101 compresses and discharges the inhaled refrigerant. Here, although not particularly limited, the compressor 101 may be configured such that its capacity (the amount of refrigerant discharged per unit time) can be changed by arbitrarily changing the operating frequency, for example, by an inverter circuit. The flow path switching device 102 is, for example, a four-way valve, and switches between cooling operation and heating operation by switching the direction of refrigerant flow. Note that instead of a four-way valve, a combination of a two-way valve and a three-way valve may be used as the flow path switching device 102.

[0058] The outdoor heat exchanger 103 performs heat exchange between the refrigerant and the outdoor air. For example, during heating operation, it functions as an evaporator, evaporating and vaporizing the refrigerant. During cooling operation, it functions as a condenser, condensing and liquefying the refrigerant.

[0059] The outdoor fan 104 is positioned to face the outdoor heat exchanger 103 and adjusts the airflow for the outdoor heat exchanger 103 to perform heat exchange.

[0060] The throttling device 105 reduces the pressure of the refrigerant to cause it to expand. For example, if it is configured as an electronic expansion valve, the opening degree is adjusted based on instructions from a control device (not shown).

[0061] The indoor heat exchanger 201 performs heat exchange between the refrigerant and the outdoor air. For example, during cooling operation, it functions as an evaporator, evaporating and vaporizing the refrigerant. During heating operation, it functions as a condenser, condensing and liquefying the refrigerant.

[0062] The indoor blower 202 is positioned opposite the indoor heat exchanger 201 and adjusts the airflow for which the indoor heat exchanger 201 performs heat exchange.

[0063] Next, the flow of refrigerant during cooling and heating operation of the air conditioner according to Embodiment 8 will be described.

[0064] During cooling operation, the flow path switching device 102 is switched to direct the refrigerant discharged from the compressor 101 into the outdoor heat exchanger 103, as shown by the solid line in Figure 14. The low-temperature, low-pressure refrigerant is then compressed by the compressor 101 and discharged as a high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 101 flows into the outdoor heat exchanger 103 via the flow path switching device 102. The high-temperature, high-pressure gaseous refrigerant that flows into the outdoor heat exchanger 103 condenses while releasing heat into the outdoor air, becoming a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that flows out of the outdoor heat exchanger 103 is then depressurized into a low-temperature, low-pressure two-phase refrigerant by the throttling device 105, flows out of the outdoor unit 100, passes through the liquid refrigerant piping 400, and flows into the indoor unit 200. The low-temperature, low-pressure two-phase refrigerant that flows into the indoor unit 200 flows into the indoor heat exchanger 201, which acts as an evaporator, and cools the indoor air by absorbing heat from it, becoming a low-temperature, low-pressure gaseous refrigerant. The low-temperature, low-pressure gaseous refrigerant that flows out of the indoor heat exchanger 201 flows through the gaseous refrigerant piping 300 into the outdoor unit 100. The refrigerant that flows into the outdoor unit 100 is drawn into the compressor 101 via the flow path switching device 102.

[0065] On the other hand, during heating operation, the flow path switching device 102 is switched so that the refrigerant discharged from the compressor 101 flows into the indoor heat exchanger 201, as shown by the dashed line in Figure 14. The low-temperature, low-pressure refrigerant is then compressed by the compressor 101 and discharged as a high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 101 flows out of the outdoor unit 100 via the flow path switching device 102, passes through the gaseous refrigerant piping 300, and flows into the indoor unit 200. The high-temperature, high-pressure gaseous refrigerant that flows into the indoor unit 200 dissipates heat into the indoor air in the indoor heat exchanger 201, becoming a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that flows out of the indoor heat exchanger 201 flows out of the indoor unit 200, passes through the liquid refrigerant piping 400, and flows into the outdoor unit 100. The high-pressure liquid refrigerant flowing into the outdoor unit 100 is reduced in pressure to a low-temperature, low-pressure two-phase refrigerant by the throttling device 105, and then flows into the outdoor heat exchanger 103. The low-temperature, low-pressure two-phase refrigerant flowing into the outdoor heat exchanger 103 absorbs heat from the outdoor air and becomes a low-temperature, low-pressure gaseous refrigerant. The low-temperature, low-pressure gaseous refrigerant flowing out of the outdoor heat exchanger 103 is drawn into the compressor 101 via the flow path switching device 102.

[0066] As described above, the air conditioning system 500 is configured, and by switching the flow of the refrigerant using the flow path switching device 102 of the outdoor unit 100, cooling and heating operations can be achieved.

[0067] As described above, the air conditioning system 500 according to Embodiment 8 is equipped with a centrifugal blower 1 according to any of Embodiments 1 to 7.

[0068] According to the air conditioning device 500 of Embodiment 8, the same effects as the centrifugal blower 1 according to any of Embodiments 1 to 7 can be obtained.

[0069] 1 Centrifugal blower, 10 Impeller, 10a Impeller intake, 11 Main plate, 11a Flow path, 11b Shaft section, 12 Blades, 12a Positive pressure surface, 12b Negative pressure surface, 13 Side plate, 13a Side of positive pressure surface, 13b Side of negative pressure surface, 13c Vertical section, 13i Inner circumference end, 13o Outer circumference end, 14 Guide, 14i Inner circumference end, 26 Bell mouth, 26d Downstream end, 100 Outdoor unit, 101 Compressor, 102 Flow path switching device, 103 Outdoor heat exchanger, 104 Outdoor blower, 105 Throttle device, 200 Indoor unit, 201 Indoor heat exchanger, 202 Indoor blower, 221 Extension plate, 222 Diffuser plate, 300 Gas refrigerant piping, 400 Liquid refrigerant piping, 500 air conditioning system.

Claims

1. A centrifugal blower comprising an impeller having a disc-shaped main plate, a plurality of blades arranged circumferentially on the periphery of the main plate, and an annular side plate positioned opposite the main plate and fixing the plurality of blades, wherein an impeller intake port is provided on the side plate side of the impeller, and each of the plurality of blades is provided with at least one guide on the negative pressure surface and opposite the side plate, wherein the at least one guide is provided closer to the side plate than the main plate, and is curved such that its shape in the direction along the negative pressure surface is convex toward the main plate, and its inner circumferential end is curved toward the impeller intake port.

2. The centrifugal blower according to claim 1, wherein at least one guide has a rib shape protruding from the negative pressure surface.

3. The centrifugal blower according to claim 2, wherein at least one guide has a shape in which the protruding width gradually decreases toward the main plate side.

4. The centrifugal blower according to claim 2 or 3, wherein each of the plurality of blades is hollow, formed by combining a separate positive pressure surface and a negative pressure surface, and at least one guide is integrally formed with the negative pressure surface.

5. The centrifugal blower according to any one of claims 2 to 4, wherein the at least one guide is a plurality, each having a different protruding width.

6. The centrifugal blower according to claim 5, wherein the protruding width of the guide closest to the side plate is the largest among the multiple guides.

7. The centrifugal blower according to claim 1, wherein at least one guide is formed by a portion of the negative pressure surface being recessed toward the positive pressure surface.

8. The centrifugal blower according to claim 7, wherein the at least one guide is a plurality and is stepped.

9. A centrifugal blower according to any one of claims 1 to 8, wherein the inner end of at least one guide is located on the inner side of the downstream end of the bell mouth.

10. The centrifugal blower according to any one of claims 1 to 9, wherein the side plate has a curved shape that is convex toward the main plate, and the negative pressure side portion has a greater curvature than the positive pressure side portion.

11. An air conditioning system comprising a centrifugal blower according to any one of claims 1 to 10.

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