Multi-blade blower and indoor unit

Abstract

To provide a multi-blade blower capable of reducing miscellaneous vortexes to reduce a variation in the surface pressure of blades and reduce noise.SOLUTION: A scroll casing 2 has a scroll part 4, an intake-side opening 5, and a blowout-side opening 6. The intake-side opening 5 opens toward the direction of a rotation axis 99 of a sirocco fan 3 and extends to be tapered toward the inside of the scroll casing 2. A serration 14 formed by protrusions and recesses is provided on an inner peripheral portion of the intake-side opening 5.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a multi-wing blower that sucks in a gas-phase fluid flow (hereinafter referred to as an air flow) in the direction of the rotation axis by rotating and exhausts it in the radial direction, and an indoor unit equipped with this multi-wing blower.

Background Art

[0002] Patent Document 1 discloses a sirocco fan provided with a first protrusion provided on the outer periphery of a fan rotor and extending in the radial direction of the fan rotor, a second protrusion provided on the outer periphery of the fan rotor and extending in the direction of the rotation axis of the fan rotor, a shielding plate provided on the housing and facing the first protrusion from the radial direction of the fan rotor, and a surrounding portion provided on the housing and surrounding the tip of the second protrusion. A first labyrinth portion is formed by the first protrusion and the shielding plate, and a second labyrinth portion is formed by the second protrusion and the surrounding portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a multi-wing blower and an indoor unit that can reduce turbulent vortices, reduce fluctuations in the surface pressure of the blades, and reduce noise.

Means for Solving the Problems

[0005] The multi-wing blower of the present disclosure is a multi-wing blower including a scroll casing and a sirocco fan. The scroll casing has a scroll portion, a suction-side opening, a blow-out-side opening, and a tongue portion. The suction-side opening opens in the direction of the rotation axis of the sirocco fan, and inside the scroll casing Towards the axis of rotationTapered and extended The suction nozzle has the following shape, and the inner circumference of the outlet end face of the suction side opening is formed such that the outlet end face of the suction side opening is inclined with respect to the rotation axis at the position where the circulating flow flowing from the scroll section toward the suction side opening and the main flow flowing from the suction side opening toward the sirocco fan merge, and the outlet end face It is provided with serrations formed by irregularities. [Effects of the Invention]

[0006] The multi-blade blower of the present invention can reduce turbulence generated at the outlet of the suction nozzle, thereby reducing fluctuations in the surface pressure of the blades caused by turbulence colliding with the blades, and thus reducing noise. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the indoor unit in Embodiment 1 [Figure 2] Vertical cross-sectional view of the indoor unit in Embodiment 1 [Figure 3] Diagram showing the refrigeration cycle circuit in Embodiment 1 [Figure 4] Perspective view showing a multi-blade blower in Embodiment 1 [Figure 5] Perspective view showing a multi-blade blower in Embodiment 1 [Figure 6] Conceptual diagram showing the relationship between serrations and longitudinal vortices. [Figure 7] Figures 7(a), (b), and (c) are explanatory diagrams showing the relationship between the main flow and the circulating flow. [Figure 8] An explanatory diagram illustrating the concept of longitudinal vortex formation. [Modes for carrying out the invention]

[0008] (Knowledge and other information that formed the basis of this disclosure) At the time the inventors conceived of this disclosure, there was a technology to reduce circulating flow by increasing airflow resistance and thereby reducing noise by lowering the rotational speed at the same airflow rate, by providing expanding, contracting, or diverting air passages composed of side plates, ribs, and a sirocco fan for circulating airflow. However, the inventors discovered that conventional technology generates vortices because the velocity difference between the main flow and the circulating flow is not mitigated when they merge. These vortices are then drawn into the blade, causing fluctuations in the surface pressure of the blade and generating noise. To solve this problem, the inventors have developed the subject matter of this disclosure. This disclosure provides a multi-blade blower and indoor unit that can reduce noise by reducing turbulence and thus reducing fluctuations in surface pressure of the blades.

[0009] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The attached drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) Embodiment 1 will be described below with reference to the drawings. [1-1. Structure] [1-1-1. Indoor Unit Configuration] Figure 1 is a cross-sectional view of the indoor unit of an air conditioner. Figure 2 is a cross-sectional view of the indoor unit. As shown in Figures 1 and 2, the air conditioner 100 in this embodiment includes a box-shaped housing 101. The housing 101 includes a top plate 102 and a bottom plate 103. In Figure 1 of the housing 101, the left side is the ventilation chamber 104, and the right side of the housing 101 is the heat exchanger chamber 105, which houses the indoor heat exchanger 33. The ventilation chamber 104 and the heat exchanger chamber 105 are separated by a partition wall 106.

[0011] An intake opening 5 for drawing in indoor air is provided at the rear of the ventilation chamber 104, and an indoor ventilation device 49 is housed inside the ventilation chamber 104. Details of the indoor air blower 49 will be described later.

[0012] [1-1-2. Configuration of Refrigeration Cycle] Next, a refrigeration cycle device, which is an example of a device using the multi-blade blower 1 of the present invention, will be described. FIG. 3 is a configuration diagram of a refrigeration cycle in an embodiment of the present invention. In FIG. 3, the refrigeration cycle device 20 includes a main circuit 21, a compressor 31, an outdoor heat exchanger 32, an indoor heat exchanger 33, a four-way valve 40, an outdoor expansion valve 45, an indoor expansion valve 46, a refrigerant storage tank 47, an outdoor air blower 48, and an indoor air blower 49. And it has a configuration that can switch the operation of dissipating heat in the outdoor heat exchanger 32 and absorbing heat in the indoor heat exchanger 33, or absorbing heat in the outdoor heat exchanger 32 and dissipating heat in the indoor heat exchanger 33. A device that uses the refrigeration cycle device 20 for the purpose of heating or cooling air is called an air conditioner or the like, and a device that uses it for the purpose of heating or cooling water is called a chiller or the like.

[0013] Also, as a form of the refrigeration cycle device 20, it may be configured by separating units into an outdoor unit 22 including a compressor 31, an outdoor heat exchanger 32, a four-way valve 40, an outdoor expansion valve 45, a refrigerant storage tank 47, and an outdoor air blower 48, and an indoor unit 23 including an indoor heat exchanger 33, an indoor expansion valve 46, and an indoor air blower 49, or the outdoor unit 22 and the indoor unit 23 may be configured as an integrated unit. Also, in the configuration where the outdoor unit 22 and the indoor unit 23 are separated, there are cases where the number of the outdoor unit 22 and the indoor unit 23 is the same and cases where the number of the indoor unit 23 is more than that of the outdoor unit 22.

[0014] In the present embodiment, a configuration example of an air conditioner in which the outdoor unit 22 and the indoor unit 23 are separated and there is one outdoor unit 22 and one indoor unit 23, which is often seen in household air conditioners and store air conditioners, is shown. The main circuit 21, when performing the operation of releasing heat in the outdoor heat exchanger 32 and absorbing heat in the indoor heat exchanger 33, connects the compressor 31, the first path 41 of the four-way valve 40, the outdoor heat exchanger 32, the outdoor expansion valve 45, the refrigerant storage tank 47, the indoor expansion valve 46, and the indoor heat exchanger 33 in this order, and is a circuit that returns from the indoor heat exchanger 33 to the compressor 31 via the second path 42 of the four-way valve 40. The compressor 31 and the first path 41 of the four-way valve 40 are connected by a flow path 91, the first path 41 of the four-way valve 40 and the outdoor heat exchanger 32 are connected by a flow path 92, the outdoor heat exchanger 32 and the outdoor expansion valve 45 are connected by a flow path 93, the outdoor expansion valve 45 and the refrigerant storage tank 47 are connected by a flow path 94, the refrigerant storage tank 47 and the indoor expansion valve 46 are connected by a flow path 95, the indoor expansion valve 46 and the indoor heat exchanger 33 are connected by a flow path 96, the indoor heat exchanger 33 and the second path 42 of the four-way valve 40 are connected by a flow path 97, and the second path 42 of the four-way valve 40 and the compressor 31 are connected by a flow path 98.

[0015] Furthermore, when the outdoor heat exchanger 32 absorbs heat and the indoor heat exchanger 33 releases heat, the compressor 31, the third path 43 of the four-way valve 40, the indoor heat exchanger 33, the indoor expansion valve 46, the refrigerant storage tank 47, the outdoor expansion valve 45, and the outdoor heat exchanger 32 are connected in this order, and the circuit returns the refrigerant from the outdoor heat exchanger 32 to the compressor 31 via the fourth path 44 of the four-way valve 40.

[0016] The compressor 31 and the third path 43 of the four-way valve 40 are connected by a flow path 91, the third path 43 of the four-way valve 40 and the indoor heat exchanger 33 are connected by a flow path 97, the indoor heat exchanger 33 and the indoor expansion valve 46 are connected by a flow path 96, the indoor expansion valve 46 and the refrigerant storage tank 47 are connected by a flow path 95, the refrigerant storage tank 47 and the outdoor expansion valve 45 are connected by a flow path 94, the outdoor expansion valve 45 and the outdoor heat exchanger 32 are connected by a flow path 93, the outdoor heat exchanger 32 and the fourth path 44 of the four-way valve 40 are connected by a flow path 92, and the fourth path 44 of the four-way valve 40 and the compressor 31 are connected by a flow path 98. Switching of the main circuit 21 depending on the operation of the refrigeration cycle device 20 is performed by the four-way valve 40. The main circuit 21 contains a refrigerant such as R32 or R410A and compressor oil to lubricate the sliding parts of the compressor 31.

[0017] The compressor 31 is a rotary compressor, comprising a cylinder having a cylindrical internal space, a rotor positioned eccentrically with respect to the central axis inside the cylinder, a gate valve slidably housed in a slit provided in the cylinder wall and configured so that its tip is always in contact with the cylindrical surface of the rotor, and the cylinder having communication holes to the main circuit 21 on both sides of the gate valve. The outdoor heat exchanger 32 and the indoor heat exchanger 33 are fin-and-tube type heat exchangers, that is, they are made of aluminum plates about 0.1 mm thick with multiple round holes about 5 mm to 8 mm in diameter, and the round holes are bent into a collar shape, and copper or aluminum tubes are installed. Hundreds of fins are arranged in a row, the tubes are inserted into the round holes, and the tubes are pushed out to make them tightly adhere to the fins.

[0018] The four-way valve 40 is configured to allow switching between the first path 41 and the second path 42, or the third path 43 and the fourth path 44, using a valve installed inside. The outdoor expansion valve 45 and the indoor expansion valve are configured to partially restrict the flow of refrigerant by reducing the cross-sectional area of ​​the path through which the refrigerant flows relative to the main circuit 21, or by switching between blocking and opening. The refrigerant storage tank 47 is equipped with a container and two communication holes for connecting to the main circuit 21. Pipes extend from the communication holes to the bottom of the container, and the liquid phase refrigerant accumulated at the bottom of the container is returned to the main circuit 21.

[0019] The outdoor ventilation system 48 uses either an axial flow fan or a mixed flow fan. A ducted indoor unit is used as the indoor unit 23. The indoor unit 23 comprises a housing 30, an indoor heat exchanger 33, an indoor expansion valve 46, an electric motor 89, and an indoor blower 49. The housing 30 has an indoor air blower 49 and an indoor heat exchanger 33 inside, through which they pass in that order, and is equipped with communication holes at both ends that are open to the indoor atmosphere. The electric motor 89 uses a variable-speed DC inverter motor. The indoor heat exchanger 33 uses a fin and tube type. The indoor heat exchanger 33 surrounds the indoor air blower 49 with a predetermined gap, and although there is some airflow resistance, airflow can pass through.

[0020] [1-1-3. Configuration of the indoor ventilation system] Next, I will explain the indoor ventilation system. Figure 4 is a perspective view showing a multi-blade fan. Figure 5 is a perspective view showing a multi-blade fan. As shown in Figures 4 and 5, the indoor ventilation system 49 consists of a multi-blade fan 1 and an electric motor 89. The multi-blade fan 1 includes a scroll casing 2 and a sirocco fan 3. The scroll casing 2 comprises a scroll section 4, an intake opening 5, an outlet opening 6, and a tongue section 7, and is fixed to the housing 30.

[0021] The scroll section 4 has a spiral radius that expands as it moves forward in the rotational direction of the sirocco fan 3. Specifically, the expansion ratio of the Archimedes curve is used. The suction-side opening 5 opens in the axial direction of the rotation axis 99 and has a suction-side opening 5 that narrows towards the inside of the scroll casing 2 with a predetermined curvature. The discharge-side opening 6 is located at the outer peripheral end of the scroll section 4. The intake-side opening 5 and the discharge-side opening 6 are in communication and form an air passage. The tongue section 7 connects the discharge-side opening 6 and the inner peripheral end of the scroll section 4, forming an acute angle with a rounded edge of approximately 10 mm in radius.

[0022] The sirocco fan 3 comprises a main plate 10, multiple blades 11, and an end ring 12. The main plate 10 is a disc concentric with the rotating shaft 99 and is fixed to the rotating shaft 99 of the electric motor 89. The blades 11 have an inclined shape so that the rear of the sirocco fan 3 in the direction of rotation approaches the rotation axis 99, and extend parallel to the rotation axis 99 from the main plate 10. The sirocco fan 3 has 40 blades, which are arranged at equal intervals around the rotation axis 99. The end ring 12 is an annular ring and connects the blades 11 at the end of the blade 11 opposite to the main plate 10. The blades 11 extend on both sides of the main plate 10. There is a gap of about 10 mm between the scroll casing 2 and the sirocco fan 3, and the sirocco fan 3 is rotatable by the electric motor 89. The scroll casing 2 and sirocco fan 3 of the multi-blade blower are manufactured by resin molding.

[0023] The suction opening 5 is rounded with a radius of approximately 10mm to 50mm so that it protrudes towards the main flow 17. In this embodiment, the inner circumference of the suction-side opening 5 is provided with serrations 14 formed by roughly triangular-shaped irregularities. The serrations 14 have an inclination of 3° to 30° relative to the rotation axis 99 at the outlet angle of the suction-side opening 5. Furthermore, the serrations 14 are formed such that when the depth of one recess is H and the width is W, the W / H ratio is between 0.3 and 5.0.

[0024] {1-2. Effect] The operation and function of the refrigeration cycle device 20 and the multi-blade blower 1, configured as described above, will be explained below. When the refrigeration cycle unit 20 operates by dissipating heat in the outdoor heat exchanger 32 and absorbing heat in the indoor heat exchanger 33, in the main circuit 21, the refrigerant sealed in the main circuit 21 is drawn into the compressor 31 in a low-temperature, low-pressure gaseous state and compressed into a high-temperature, high-pressure gaseous state by the compressor 31. The direction of flow of the refrigerant is selected by the four-way valve 40 and it flows to the outdoor heat exchanger 32, where it dissipates heat and becomes a medium-temperature, medium-pressure liquid state. After being stored in the refrigerant storage tank 47, the amount of refrigerant flowing is adjusted by the indoor expansion valve 46 and it is discharged, absorbs heat from the outside air in the indoor heat exchanger 33 and evaporates, returning to a low-temperature, low-pressure gaseous state, and is compressed again into a high-temperature, high-pressure gaseous state by the compressor 31. This series of actions transfers heat from the room to the outside via the refrigerant, resulting in the cooling operation of an air conditioner.

[0025] Furthermore, when the refrigeration cycle unit 20 performs the operation of absorbing heat in the outdoor heat exchanger 32 and releasing heat in the indoor heat exchanger 33, in the main circuit 21, the refrigerant sealed in the main circuit 21 is drawn into the compressor 31 in a low-temperature, low-pressure gaseous state and compressed into a high-temperature, high-pressure gaseous state by the compressor 31. The direction of flow of the refrigerant is selected by the four-way valve 40 and it flows to the indoor heat exchanger 33, where it releases heat and becomes a medium-temperature, medium-pressure liquid refrigerant. After being stored in the refrigerant storage tank 47, the amount of refrigerant flowing is adjusted by the outdoor expansion valve 45 and it is discharged, releasing heat into the outside air in the outdoor heat exchanger 32 and evaporating, returning to a low-temperature, low-pressure gaseous state, and then compressed again into a high-temperature, high-pressure gaseous state by the compressor 31. This series of actions transfers heat from the outside into the room via the refrigerant, resulting in the heating function of an air conditioner. In particular, when heat is released or absorbed in the indoor heat exchanger 33, a multi-blade fan 1 is used to generate airflow, improving heat exchange efficiency and circulating temperature-controlled air in the room.

[0026] The airflow generated by the multi-blade fan 1 is drawn in at room temperature through the intake opening 5 of the scroll casing 2, pressurized by the sirocco fan 3, flows through the scroll section 4, and is exhausted at room temperature through the outlet opening 6. Subsequently, it passes through the indoor heat exchanger 33, where it exchanges heat with the refrigerant, becoming cooled during cooling operation and heated during heating operation before being blown out from the housing 30.

[0027] In Figure 4, the scroll casing 2 and the electric motor 89 are fixed to a housing 30 (not shown), and the sirocco fan 3 is rotationally driven by the electric motor 89. The airflow is drawn in from the intake opening 5 in the axial direction of the rotating shaft 99, passes through the blades 11, is pressurized while swirling around the scroll section 4, and is blown out from the discharge opening 6.

[0028] On the other hand, as can be seen from the fact that airflow flows from areas of high pressure to areas of low pressure, and that airflow is drawn in through the intake opening 5 and blown out through the outlet opening 6, the inside of the blade 11 is partially under pressure relative to the surrounding pressure, while the outside is under pressure. In other words, the inside of the scroll casing 2, which is located outside the blade 11, is under higher pressure than the intake opening 5, which is located inside the blade 11. Therefore, as shown in Figure 5, a circulating flow 18 is generated, which is an airflow leaking from the scroll section 4 toward the suction opening 5.

[0029] Figure 6 is a conceptual diagram showing the relationship between serrations and longitudinal vortices. When the circulating flow 18 merges with the main flow 17 without its velocity being reduced, turbulent vortices are generated. As shown in Figure 6, there are many vortices disturbed by the blade 11 around the blade 11, but it can also be seen that relatively strong turbulent vortices are generated downstream of the intake opening 5. The rotational speed of the blade 11 is, for example, 10 m / s to 20 m / s, while the wind speed of the intake airflow is slow, only a few m / s. Therefore, when turbulent air is drawn into the sirocco fan 3, it cannot pass through the gaps between the blades 11 and is cut off by multiple blades 11. Because the internal pressure of a vortex decreases due to centrifugal force, the surface pressure of the blade 11 is the same as the surrounding area before cutting the vortex, decreases when cutting the vortex, and recovers after passing through the vortex. In other words, the surface pressure of the blade 11 oscillates. And since pressure oscillation is sound wave itself, noise is generated.

[0030] In contrast, by inclining the outlet of the suction-side opening 5 toward the rotation axis 99 and providing serrations 14 on the end face of the outlet of the suction-side opening 5, the main flow 17 flows in with respect to the serrations 14 at a serration inflow angle 15, generating longitudinal vortices 19 that flow in the direction of the main flow 17 but have a rotational component in a plane perpendicular to the direction of the main flow 17. Unlike random vortices whose direction and size are not fixed, the longitudinal vortices 19 are structural vortices with relatively stable strength and direction.

[0031] Next, we will explain the concept of mixing airflows with velocity differences by serrations 14. The serrations 14 have the function of generating longitudinal vortices that swirl on a plane perpendicular to the direction of airflow as airflow begins to leak out from their recesses. Therefore, the serrations 14 are effective when they are angled to slightly block the airflow, or when there is a pressure difference on both sides of the plate with the serrations 14, causing a swirling flow. Conversely, if there is no pressure difference on both sides of the plate and the air flows parallel, the effect of the serrations cannot be obtained.

[0032] Figures 7(a), (b), and (c) are explanatory diagrams showing the relationship between the main flow and the circulating flow. Here, in Figure 7(a), if there are no serrations 14 at the suction nozzle outlet 13 and no tapering toward the rotating shaft 99, the directions of the main flow and the circulating flow are parallel at the confluence of the main flow and the circulating flow, but because the velocity gradient between these airflows is large, a vortex is generated downstream of the suction nozzle outlet 13, as shown in Figure 6. As a result, this vortex is drawn into the sirocco fan 3 and collides with the blades 11, causing fluctuations in the surface pressure of the blades 11, which generates an NZ sound with a peak at the frequency of (number of blades × rotation speed), and increases noise.

[0033] Furthermore, as shown in Figure 7(b), if the suction nozzle outlet 13 does not have serrations 14 and tapers toward the rotating shaft 99, the circulating flow flows along the slope of the suction nozzle outlet 13. As a result, in addition to the velocity gradient, the element of airflow collision is added, generating larger vortices. Furthermore, as shown in Figure 7(c), if the suction nozzle outlet 13 has serrations 14 and there is no tapering toward the rotation axis 99, the serrations 14 are positioned parallel to the airflow, whereas their effect is obtained when they are positioned diagonally with respect to the direction of airflow. In this case, it is equivalent to the case where there are no serrations 14, so the effect of the serrations 14 is not obtained, and vortices are generated.

[0034] In contrast, the multi-blade blower of this embodiment is provided with serrations 14 at the suction nozzle outlet 13 and tapers toward the rotation axis 99, so that the suction nozzle outlet 13 is positioned at an angle to the main flow, thereby mitigating the velocity gradient and reducing vortices. Since vortices are reduced, noise is reduced.

[0035] Figure 8 is an explanatory diagram illustrating the concept of longitudinal vortex formation. As shown in Figure 8, when airflow hits the suction-side opening 5 at an angle to the serrations 14, airflow leaks out continuously in the recesses of the serrations 14 in the direction of travel, and this continuous leakage creates a structure that combines a component in the direction of travel and a component in the direction of rotation, similar to a screw thread. The multi-blade blower 1 of the present disclosure has an inclination of 3° to 30° with respect to the rotation axis at the angle of the outlet of the suction-side opening, and is provided with serrations on the outlet-side end face of the suction-side opening where the depth of one recess is H and the width is W, and W / H is 0.3 to 5.0, and both H and W are greater than or equal to the plate thickness of the suction-side opening. As a result, the main flow 17 flows in with a serration inflow angle 15 relative to the serrations 14, and longitudinal vortices 19 are generated between the main flow 17 and the circulating flow 18 by the recesses of the serrations, mixing the airflows and thus mitigating the velocity gradient and reducing turbulent vortices.

[0036] [1-3. Effects, etc.] As described above, in this embodiment, the scroll casing 2 has a scroll section 4, an intake-side opening 5, and an outlet-side opening 6. The intake-side opening 5 opens in the direction of the rotation axis 99 of the sirocco fan 3 and tapers inward toward the inside of the scroll casing 2. The inner circumference of the intake-side opening 5 is provided with serrations 14 formed by irregularities. This reduces turbulence at the outlet of the intake opening 5, thereby reducing fluctuations in the surface pressure of the blades 11 and lowering the noise of the multi-blade blower 1.

[0037] Furthermore, in this embodiment, the irregularities are formed by triangular irregularities. As a result, the serrations 14, which are formed in a triangular pattern, can reduce turbulence at the outlet of the intake opening 5, thereby reducing fluctuations in the surface pressure of the blades 11 and reducing the noise of the multi-blade blower 1.

[0038] Furthermore, in this embodiment, the serrations 14 are formed such that when the depth of one recess is H and the width is W, the W / H ratio is between 0.3 and 5.0, and both H and W are greater than or equal to the plate thickness of the suction-side opening. As a result, the main flow 17 flows in with a serration inflow angle 15 relative to the serrations 14, and longitudinal vortices 19 are generated between the main flow 17 and the circulating flow 18 by the recesses of the serrations, mixing the airflows. This reduces the velocity gradient and minimizes turbulence.

[0039] (Other embodiments) As described above, Embodiment 1 has been explained as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this and can be applied to embodiments that have been modified, replaced, added, or omitted. Therefore, other embodiments are illustrated below. The compressor 31 may be of a rotary, scroll, reciprocating, or turbo type. Furthermore, the compressor 31 may be powered by an electric motor built into the compressor 31, by an electric motor independent of the compressor 31, or by a prime mover instead of an electric motor. Any mechanism capable of compressing a gaseous refrigerant is acceptable, regardless of its type or power source.

[0040] Furthermore, the indoor unit 23 may be a chiller module that regulates the temperature of water instead of the indoor air, and may be integrated into a chemical fractionation distillation facility or the like, rather than being in the form of a separate enclosure. As long as the main circuit 21 is capable of heat exchange with the outside, the object or form of temperature regulation is not restricted. Furthermore, the indoor heat exchanger 33 may be a heat exchanger in the form of a series of flat tubes, or it may be a heat exchanger in the form of a microchannel heat exchanger, where the refrigerant side has multiple microchannels integrated and the air side has a collection of fins. Any type is acceptable as long as it allows the airflow generated by the indoor blower 49 to pass through and performs heat exchange.

[0041] Furthermore, the electric motor 89 may be a constant-speed DC motor or an AC motor, or it may be any other rotary drive device, not limited to an electric motor. The type of device is not specified as long as it can rotary drive the indoor ventilation device 49. Furthermore, the refrigerant sealed in the main circuit 21 may be CO2 or other substances that do not undergo a phase change, and the type of refrigerant is not limited. Furthermore, the suction-side opening 5 may be nozzle-shaped, facing inward towards the scroll casing 2, or it may be a simple round hole.

[0042] Furthermore, although the multi-blade blower 1 is manufactured by resin molding in this invention, part or all of it may be made of sheet metal, cast iron, or machined metal. In addition, while other curves such as involute curves may be used for the scroll section 4 in addition to the Archimedes curve, the effect of the change in airflow due to the shape of the scroll section 4 on the airflow that collides with the tongue section 7 is small, so applying the uneven section 16 has a noise reduction effect.

[0043] Furthermore, the number of blades in the Sirocco fan 3 can be any number. Generally, there are many with around 30 to 50 blades. The blades 11 do not necessarily have to extend parallel to the rotation axis 99. In terms of production, using a single-axis mold is often used because it is low cost, and the blades 11 are often made parallel to the rotation axis 99 so that they can be removed from the mold even with a single axis. However, a three-dimensional blade shape can also be formed by using a slide core or by applying post-molding processing such as welding or fusion. Also, if deformation does not pose a practical problem, such as when the length of the blade 11 extension is short, an end ring is not necessary.

[0044] (Note) Based on the above description of embodiments, the following technologies are disclosed. (Technical 1) A multi-blade blower comprising a scroll casing and a sirocco fan, wherein the scroll casing has a scroll portion, an intake side opening, an outlet side opening, and a tongue portion, the intake side opening opens in the direction of the rotation axis of the sirocco fan and extends tapered toward the inside of the scroll casing, and the inner circumference of the intake side opening is provided with serrations formed by irregularities. This configuration reduces turbulence at the outlet of the intake opening, thereby minimizing fluctuations in surface pressure on the blades. As a result, noise from the multi-blade blower can be reduced.

[0045] (Technology 2) The multi-blade blower according to Technology 1, wherein the irregularities are formed by triangular irregularities. This configuration, with its triangular serrations, reduces turbulence at the outlet of the intake opening, thereby minimizing fluctuations in surface pressure of the blades. As a result, noise from the multi-blade blower can be reduced.

[0046] (Technology 3) The multi-blade blower according to Technology 1 or Technology 2, wherein the serrations are formed such that when the depth of one recess is H and the width is W, the ratio W / H is 0.3 or more and 5.0 or less, and both H and W are greater than or equal to the plate thickness of the suction side opening. In this configuration, the main flow enters the serrations at a serration inflow angle, and longitudinal vortices are generated between the main flow and the circulating flow by the recesses in the serrations, mixing the airflows. As a result, the velocity gradient is mitigated and turbulent vortices can be reduced.

[0047] (Technical 4) An indoor unit comprising a multi-blade fan as described in any one of Technical 1 to Technical 3, and an indoor heat exchanger positioned opposite the outlet opening. This configuration reduces turbulence at the outlet of the intake opening, thereby minimizing fluctuations in the surface pressure of the blades. As a result, it is possible to obtain an indoor unit that can reduce the noise of the multi-blade blower. [Industrial applicability]

[0048] As described above, the multi-blade blower according to the present invention can reduce noise, and can therefore be applied to a wide range of equipment that uses multi-blade blowers, including not only refrigeration cycle equipment such as air conditioners and chillers, but also air handling equipment such as circulators and duct ventilation systems, ventilation systems, intake and exhaust systems for combustion appliances such as fan heaters, and air circulation systems for biobenches. [Explanation of Symbols]

[0049] 1 multi-blade blower 2. Scroll casing 3 Sirocco fan 4. Scroll section 5. Suction side opening 6. Outlet side opening 7. Tongue 8 Starting end 9 End end 10 Main plate 11 wings 12 end rings 13 steps 14-wire sound source section 15 point sound source section 16 Uneven part 17 Uneven mountain height 18 Uneven mountain width 19. Length of unevenness 20 Refrigeration cycle equipment 21 Main circuit 22 Outdoor unit 23 Indoor unit 30 cabinets 31 Compressor 32 Outdoor heat exchanger 33 Indoor heat exchanger 40 Square valve 41 First pathway of the four-way valve 42 Second pathway of the four-way valve 43 Third pathway of the four-way valve 44. Fourth pathway of the four-way valve 45 Outdoor expansion valve 46. ​​Indoor expansion valve 47 Refrigerant storage tank 48 Outdoor ventilation system 49 Indoor ventilation system 89 Electric motor 91-98 Channel 99 rotational axes 101 cabinets 102 Top plate 103 Bottom plate 104 Ventilation room 105 Heat exchanger room 106 Partition wall

Claims

1. A multi-blade blower comprising a scroll casing and a sirocco fan, The scroll casing has a scroll section, an intake side opening, an outlet side opening, and a tongue section. The aforementioned suction-side opening opens in the direction of the rotation axis of the sirocco fan and has a suction nozzle shape that tapers in the direction of the rotation axis toward the inside of the scroll casing. On the inner circumference of the outlet end face of the suction-side opening, at the point where the circulating flow flowing from within the scroll section toward the suction-side opening and the main flow flowing from the suction-side opening toward the sirocco fan merge, the outlet end face of the suction-side opening is formed to be inclined with respect to the rotation axis, and serrations formed by irregularities are provided on the outlet end face. Multi-blade blower.

2. The aforementioned irregularities are formed by triangular irregularities. A multi-blade blower according to claim 1.

3. The serrations are formed such that, when the depth of one recess is H and the width is W, the ratio W / H is between 0.3 and 5.0, and both H and W are greater than or equal to the plate thickness of the suction-side opening. A multi-blade blower according to claim 1 or claim 2.

4. A multi-blade blower according to claim 1, It comprises an indoor heat exchanger positioned opposite the outlet opening, Indoor unit.

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