JPH0639959B2 - Centrifugal blower - Google Patents

Description

TECHNICAL FIELD The present invention relates to a centrifugal blower capable of exhibiting high performance in a large air volume range.

(Prior Art) A generally used centrifugal blower having a short axial length has a thin outer periphery of a disk-shaped impeller main plate (7) supported by a motor as shown in FIG. Centrifugal impeller in which blades (8) are projected from the portion in a distributive arrangement with an equal angle in the axial direction, and the blades (8), (8) are connected by a ring-shaped impeller side plate (9). (Four)
Is rotatably housed in the housing, and approaches the blade end surface on the side having the impeller side plate (9),
The suction port (5) provided on the front plate (1) of the housing is facing, but there is no problem in low air volume operation with low rotation speed, but in high air volume operation, suction port (5) Blades that rotate due to the large flow velocity of the axial component of the air introduced from
Due to (8), the air flow lacks smoothness even if it rolls at a right angle, and in particular, a swirl as shown in the figure on the back side of the impeller side plate (9) occurs, and this part is considerably large dead water area. Therefore, it has been found that the effective portion of each vane (8) that functions to apply energy is reduced accordingly.

(Problems to be Solved by the Invention) When the effective portion of the blade is reduced in this way, the wind passes through the limited blade portion at a high speed, resulting in a large pressure loss. However, there is a problem that the performance in the high air volume region sharply decreases.

In response to such a problem, the present invention has been made to provide a centrifugal blower capable of significantly reducing pressure loss and guaranteeing high performance not only in a low air volume region but also in a high air volume region. In a predetermined area portion of the blade where the vortex flow is likely to occur, a part of the wind generated by the blower itself is used to form a structure capable of sending a jet flow that can be eliminated by attracting the vortex flow, The purpose is to expand the effective portion of the blade and try to maintain high efficiency.

(Means for Solving Problems) Therefore, according to the present invention, as is apparent from the drawings showing the embodiments, the vicinity of the scroll outlet portion (6) of the housing front plate (1) having the suction port (5) is provided. And a suction opening (11) capable of introducing a part of blown air, and an end surface on the suction port (5) side of a centrifugal impeller (4) having a large number of blades (8) on the outer periphery. Suction port of the housing front plate (1) in the shape of a ring
(5) A blowout opening (12) which is provided in the peripheral portion and is capable of ejecting airflow by obliquely crossing from the inner peripheral portion of the end face of the impeller (4) toward the outer peripheral side of the blades (8) and (8). ) And a housing front plate extending between the suction opening (11) and the blowout opening (12).
The centrifugal blower is provided with an air guide passage (13) arranged alongside (1), and the suction opening (11) is provided in the middle of the air guide passage (13).
The airflow guide plate (15) is provided so as to be circumscribed from the end on the side close to the tongue to the outer peripheral edge of the centrifugal impeller (4).

(Operation) In the present invention, which is provided with the above-mentioned means, the air flow guide plate (15) is introduced after being introduced into the air guide flow path (13) through the scroll outlet portion (11) particularly during high air volume operation during air blowing operation. ) Is guided to the blowout opening (12) without short-circuit flow, and the suction opening (5) of the centrifugal impeller (4) is guided from the ring-shaped blowout opening (12).
As a result, the eddy current generated on the back side of the impeller side plate is attracted by the jet air flow and the dead water region disappears or shrinks, so that the effective part of the blade is discharged. It can be extended to almost the entire length, thus reducing the pressure loss.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a thin centrifugal blower having a short axial length, which has blades directly connected to the motor, and the housing is
A housing front plate (1) having a circular suction port (5) surrounded by a lip at the center of the scroll, and a shaft hole for the suction port.
A housing rear plate (2) having the same shape as the housing front plate (1) and having a coaxial symmetry with (5), and a housing front / rear plate (excluding the scroll outlet portion (6) serving as an air outlet, which face each other It is composed of housing side plates (3) provided between the peripheral edges of (1) and (2).

A centrifugal impeller (4) is housed in the housing, and a motor (fixed to the housing rear plate (2) with respect to the boss at the center of the disk-shaped impeller main plate (7) ( The rotary shaft of 10) penetrates through the shaft hole and is fitted to the centrifugal impeller.
(4) is directly connected to the motor (10) by one-sided support and integrated.

The centrifugal impeller (4) includes an impeller main plate (7) and a plurality of blades (8), (8) projecting from the outer peripheral portion of the main plate (7) in an axial direction in a dispersive arrangement with an equal angle. ), And an impeller side plate (9) having an annular shape formed by connecting the suction port (5) side ends of the blades (8) and (8) to each other. (9) is each blade
(8). The blades are not extended over the entire width extending in the radial direction of the impeller (8) but over the half width on the outer peripheral edge side.
It is connected to (8) and (8).

The blower having such a structure drives the motor (10) to rotate the centrifugal impeller (4) in the counterclockwise direction in FIG. 2 so that each impeller (8) of the impeller (4), (8) is to blow air by inducing air from the suction port (5) in the axial direction and sending it out in the centrifugal direction by turning 90 ° direction, and blowing out from the scroll outlet part (6), The motor (10) is controlled to rotate in a stepless or stepwise manner so that the air volume is adjusted.

In the blower, the housing front plate (11) is formed as a thin hollow plate as shown in FIG. 1, and this hollow portion serves as an air guide passage having a structure described later.

Further, in the inner surface plate of the housing front plate (1), a slit-like suction opening (11) is opened near the scroll outlet (6), for example, in parallel with the outlet (6). The opening (11) faces the air guide flow path (13).

The suction opening (11) allows a part of the blown air to flow through the air guide passage.
Regarding the opening for introduction into (13), in the illustrated example, a swash plate (14) protruding from the downstream edge into the housing is additionally provided in order to facilitate the introduction of air into the opening.

On the other hand, in the periphery of the suction port (5) of the front plate (1) of the housing, a blowout opening (formed by an annular nozzle facing the suction port (5) side end surface of the centrifugal impeller (4) ( 12) is provided,
The opening (12) faces the air guide flow path (13).

The blowout opening (12) is arranged so that the airflow can be ejected by diagonally crossing from the inner peripheral portion of the end surface of the impeller (4) toward the outer peripheral side of the blades (8) and (8) slightly rearward. Is formed.

Further, in the illustrated example, the air flow guide plate (15) is arranged at a predetermined position in the air guide flow path (13).
5) indicates that the air introduced from the suction opening (11) is the front plate of the housing.
The suction opening is provided for the purpose of preventing short-circuit flow in the blow-out opening (12) near the tongue of (1).
It is arranged in the air guide flow path (13) such that the end of (11) near the tongue is circumscribed to the outer peripheral edge of the centrifugal impeller (4). .

Next, the blower action of the blower will be described. Centrifugal impeller
When (4) is rotated to achieve a high air volume, a part of the air flow blown out from the scroll outlet (6) is introduced from the suction opening (11) into the air guide passage (13), As shown by the broken line arrow in FIG. 2, it is ejected toward the end face of the impeller (4) from the blowout opening (12) in an inward swirling flow.

As described above, a vortex is generally generated on the back surface of the impeller side plate (9) in the centrifugal impeller (4) .However, this blower has a vortex generating part where the air flow ejected from the blowout opening (12). Since it flows at a high speed diagonally across, even if a vortex is generated, it will be attracted to this jet and the scroll outlet
As a result of flowing to (6), there is no stagnation of vortex flow,
All of the parts (8) and (8) function as a centrifugal blower, so that the pressure loss in the centrifugal impeller (4) is greatly reduced.

However, as shown in FIG. 4, the blower according to the example of the present invention has a higher air flow with the same fan pressure than the conventional blower shown by the broken line, as shown in FIG. You can get it.

FIG. 3 is a partial view showing an essential part of a still another example of the present invention, in which the hollow portion of the housing front plate (1) where the suction opening (11) is opened is partially bulged to make it hollow. With a structure that expands the area, it is possible to make the commutation of the sucked air smooth with less resistance, and the outlet opening (12)
There is an advantage that the velocity of the jet flow from can be increased.

(Effect of the invention) As described above, the present invention induces and eliminates the eddy current, which is likely to occur in the hyperopic impeller (4), by the jet flow generated by utilizing a part of its own blown air. By doing so, the effective portion of the blade (8) can be expanded, the pressure loss in the high air volume region can be reduced, and the blower capable of maintaining high performance, high efficiency and low noise can be provided. Is played.

Particularly, in the present invention, the air introduced through the suction opening (11) by the air flow guide plate (15) is provided while circulating the rectified flow relatively far from the impeller with the air guide flow path (13). Since short-circuit flow is prevented and stabilized in the blowout opening (12), flow disturbance is eliminated, which is advantageous for noise prevention.

[Brief description of drawings]

1 and 2 are a side view and a front view according to one embodiment of the present invention, and FIG. 3 is a cross-sectional view of a main part according to another embodiment of the present invention,
FIG. 4 is a characteristic comparison diagram of an example of the present invention and a conventional blower, and FIG.
The figure is a side view of a conventional blower. (1) ... Housing front plate, (4) ... Centrifugal impeller, (5) ... Suction port, (6) ... Scroll outlet part, (8) ... Vane, (11) ... Suction opening part, (12) ... Outlet Opening, (13) ... Air guide flow path,

Claims (1)

[Claims] 1. A suction opening (11) which is provided in the vicinity of a scroll outlet (6) of a housing front plate (1) having a suction port (5) so that a part of blown air can be introduced, and a large number of Provided in the suction port (5) peripheral part of the housing front plate (1) in an annular shape facing the end face on the suction port (5) side of the centrifugal impeller (4) having the blade (8) on the outer periphery, A blowout opening (12) capable of ejecting airflow by obliquely traversing the inner peripheral portion of the end face of the impeller (4) toward the outer peripheral side of the blades (8) and (8), and the suction opening ( 1
1) and an air guide channel (13) extending between the blowout opening (12) and provided along the housing front plate (1), and in the air guide channel (13). A centrifugal blower characterized in that an air flow guide plate (15) is provided such that it is circumscribed from the end of the suction opening (11) near the tongue to the outer peripheral edge of the centrifugal impeller (4). .