JPH08193596A - Impeller of centrifugal blower - Google Patents

Abstract

PURPOSE: To enhance the discharge pressure, rate of flow, and efficiency in low speed operation and construct impeller in a small size by furnishing aux. vanes adjacent to the pressure surface of the main vanes. CONSTITUTION: When a centrifugal blower is in operation and its rotary shaft 1 rotates, the air introduced from a suction port 6 flows in the illustrated direction by arrow, is pressurized by main vanes 5 and aux. vanes 7, and is forwarded to the place of service via a diffuser. The ax. vanes 7 are arranged adjacently to the respective pressure surfaces of the main vanes 5, and the length L1 of aux. vane 7 is made smaller than the vane length L of the main vane 5, so that there is no need of narrowing the flow path at the inlet end 5a of the main vane 5. Further the summarized vane area of the main vanes 5 and aux. vanes 7 is increased by approx. 20-50% of the conventional value, which causes increase of the discharge pressure. The outlet angle β2' of the aux. vane 7 is made greater than the outlet angle β2 of the main vane 5. Accordingly there is no risk of separation at the negative pressure surface 52 of the main vane 5, and the mean outlet angles of the main vane 5 and aux. vane 7 are enlarged, and the lift of the vane is increased. This causes increase in the work volume of the vane to lead to enhancement of the efficiency of blower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller of a centrifugal blower.

[0002]

2. Description of the Related Art One example of a conventional impeller of a centrifugal blower is shown in FIG. In FIG. 3, 1 is a rotary shaft that is driven to rotate by a drive source such as an electric motor (not shown), 2 is a disc-shaped main plate fixed to the rotary shaft 1 by a nut 3, and 4 is an annular ring that is coaxial with the main plate 2. It is a side plate.

A plurality of blades 5 are arranged at equal intervals along the circumferential direction between the main plate 2 and the side plates 4, and both ends of the blades 5 are fixed to the main plate 2 and the side plates 4.

When the rotary shaft 1 is driven to rotate during operation of the centrifugal blower, the gas introduced into the impeller from the suction port 6 flows as shown by the arrow and is pressurized by the blades 5 and passes through a diffuser (not shown). It is sent to the destination.

In this type of centrifugal blower, it is required that a higher discharge pressure, a higher flow rate, and high efficiency can be obtained with an impeller having the same outer diameter and rotation speed.

Therefore, in order to cope with this requirement, it has been proposed to increase the number of blades 5 as shown in FIG. 4, which is to reduce the flow passage width W at the inlet end 5a of the blade 5. Therefore, the efficiency is lowered and the discharge pressure is not increased.

Further, as shown in FIG. 5, it has been proposed to bend the outlet end 5b of the wing 5 into a flap shape of an aircraft. This is because the wing length L ₀ of the wing 5 is provided with a flap-shaped bent portion. Although not present, the blade length becomes shorter than L and the flow separates at the negative pressure surface 52 of the outlet end 5b, so the discharge pressure cannot be increased.

It is an object of the present invention to provide a small-sized, low-cost impeller that has a low discharge speed, a high discharge pressure, a high flow rate, and a high efficiency.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been invented in order to achieve the above-mentioned object, and the gist of the present invention is to provide a disc-shaped main plate fixed to a rotary shaft and a coaxial main plate. In an impeller of a centrifugal blower in which a plurality of main blades are arranged at equal intervals along the circumferential direction with an annular side plate, an auxiliary blade is arranged adjacent to the pressure surface of the main blade. It is in an impeller of a centrifugal blower, which is characterized in that.

Another feature is that the exit angle of the auxiliary blade is made larger than that of the main blade.

Still another feature is that the blade length of the auxiliary blade is shorter than that of the main blade.

[0012]

In the present invention, since the area of the blade including the main blade and the auxiliary blade is increased, the discharge pressure is increased.

Further, if the outlet angle of the auxiliary blade is increased, the average outlet angle of the blade including the main blade and the auxiliary blade is increased while maintaining the outlet angle of the main blade at an angle at which flow separation does not occur. Lifting power increases.

If the auxiliary blade is arranged adjacent to the pressure surface of the main blade and the blade length of the auxiliary blade is shorter than that of the main blade, the flow passage width at the inlet end of the main blade is not narrowed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG. 1, (A) is a side view showing an impeller partially broken along its axis,
(B) is a sectional view taken along the line BB of (A).

In FIG. 1, 1 is a rotary shaft, 2 is a rotary shaft 1.
Main plate fixed to the shaft end of the nut with nut 3, 4 is a side plate, 5
Are main blades of a plurality of plates arranged at equal intervals along the circumferential direction between the main plate 2 and the side plate 4, and both ends thereof are fixed to the main plate 2 and the side plate 4.

Reference numeral 7 denotes an auxiliary wing, which is arranged adjacent to the pressure surface 51 of each main wing 5 with a space S, and both ends thereof are fixed to the main plate 2 and the side plate 4. It is desirable that the blade length L ₁ of the auxiliary blade 7 be shorter than the blade length L of the main blade 5 to be 20% to 50% of the blade length L, and that the outlet end 7b of the auxiliary blade 7 coincide with the outer peripheral edge of the main plate 2. Further, the exit angle β ′ ₂ of the auxiliary wing 7 is the exit angle β of the main wing 5.
_It is larger than ₂ (same exit angle as before).

The auxiliary wings 7 are connected to each other through the reinforcing ribs 8 at the substantially central portion of the main blade 5 in the blade length.
Has increased the rigidity of. The reinforcing rib 8 may be omitted if the auxiliary wing 7 has sufficient rigidity.

When the rotating shaft 1 rotates during operation of the centrifugal blower, the air introduced from the suction port 6 flows as shown by the arrows and is pressurized by the main blades 5 and the auxiliary blades 7 to the destination through the diffuser (not shown). Sent out.

However, since the auxiliary wing 7 is disposed adjacent to the pressure surface of the main wing 5 and the wing length L ₁ of the auxiliary wing 7 is shorter than that L of the main wing 5, the inlet end 5a of the main wing 5 is It does not narrow the width of the channel. Moreover, the total blade area of the main wing 5 and the auxiliary wing 7 is increased by about 20% to 50% as compared with the conventional one, which increases the discharge pressure.

Further, the outlet angle beta ₂ of wing 5 is the same as that of the prior art, since the outlet angle beta _'2 ailerons 7 is made larger than beta ₂ wing 5, the suction surface 52 of the wing 5 The average exit angle of the main wing 5 and the auxiliary wing 7 is increased without causing separation of the blades, thereby increasing the lift of the blade.

As a result, the work of the blade is increased by the above two effects, and as shown in FIG. 2, the pressure of the impeller of the present invention having the same diameter as the pressure P ₁ of the conventional impeller is obtained. Is P ₂
Rise to.

[0023]

According to the present invention, since the auxiliary blade is provided adjacent to the pressure surface of the main blade, the area of the blade is increased as compared with the conventional one without narrowing the inlet passage of the blade.
The discharge pressure is increased.

Further, while maintaining the exit angle of the main wing at an angle at which flow separation does not occur as in the conventional case, by making the exit angle of the auxiliary wing larger than that of the main wing, the average exit of the main wing and the auxiliary wing The angle can be increased, which can increase the lift of the wing.

Since the work of the blades is increased by the above two effects, the discharge pressure is increased and the efficiency of the blower is improved.

On the other hand, since the outer diameter of the impeller required to obtain the same pressure and the same flow rate as the conventional impeller can be reduced, the blower can be downsized and the cost can be reduced.

[Brief description of drawings]

1 shows an impeller of a centrifugal blower according to an embodiment of the present invention, (A) is a partial side view partially broken along an axis of a rotating shaft, and (B) is B of (A). FIG. 7 is a partial cross-sectional view taken along the line B.

FIG. 2 is a diagram showing the characteristics of the impeller of the present invention in comparison with a conventional example.

FIG. 3 shows an example of an impeller of a conventional centrifugal blower, (A)
[FIG. 3] is a partial side view partially broken along the axis of the rotating shaft, and (B) is a partial cross-sectional view taken along the line BB of (A).

FIG. 4 is a partial cross-sectional view showing an impeller of another conventional centrifugal blower.

FIG. 5 is a partial cross-sectional view showing an impeller of still another conventional centrifugal blower.

[Explanation of symbols]

 1 rotary shaft 2 main plate 4 side plate 5 main wing 51 pressure surface 52 negative pressure surface 7 auxiliary wing 8 rib

Claims (3)

[Claims] 1. A centrifugal machine comprising a plurality of main blades arranged at equal intervals along a circumferential direction between a disk-shaped main plate fixed to a rotating shaft and an annular side plate coaxial with the main plate. An impeller for a centrifugal blower, wherein an impeller of a blower is arranged adjacent to a pressure surface of the main blade. 2. The impeller of a centrifugal blower according to claim 1, wherein an outlet angle of the auxiliary blade is larger than that of the main blade. 3. The impeller of a centrifugal blower according to claim 1, wherein the blade length of the auxiliary blade is shorter than that of the main blade.