JPH1018993A - Sirocco fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the blowing performance of a sirocco fan requiring no enlargement of equipment incorporating the sirocco fan. SOLUTION: Holding rings 4 hold a plurality of blades 1a annularly arranged in a fan casing 2 at their both ends respectively, and a boss part 5 is provided in the center of the blades 1a. The blades 1a are formed to have their circular arc length which becomes shorter stepwise as approaching the holding rings 4 from the boss part 5. By which arrangement, high-pressure air flows on the side of the boss part 5 permit air flows inducted from the inlet port in the fan casing 2 to blow off through the blades 1a near the holding rings 4 with no separation thereof, to thereby improve the blowing performance of the sirocco fan.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sirocco fan blowing technique.

[0002]

2. Description of the Related Art Conventionally, a sirocco fan has been disclosed in Japanese Patent Application Laid-Open No. 56-6 / 1981.
No. 9499 is known. FIG.
The structure of a conventional sirocco fan is shown in FIG.
Blades 7 arranged in parallel with the rotation axis between the
The impeller 1 having a “a” is housed in a fan casing 2 provided with a bell mouth 3, and a flow indicated by an arrow A is generated.

[0003]

In this sirocco fan, more efficient air blowing performance is required.

[0004] However, the above-mentioned conventional configuration has a drawback that the air flow inside the impeller is biased toward the boss side, so that the wind speed distribution on the front side of the outlet becomes non-uniform and the air cannot be efficiently blown.

[0005] When the speed of the impeller is increased or the size thereof is increased, the amount of blown air can be increased. However, when the impeller drive rotation speed is increased, there is a disadvantage that the noise amount increases. Also,
When the size of the impeller is increased, it is inevitable to increase the size of a device equipped with a sirocco fan.

An object of the present invention is to improve the blowing performance of a sirocco fan.

[0007]

According to the present invention, there is provided an impeller in which a blade constituting an impeller is formed in a blade cross-sectional shape, and the blade arc length is gradually increased from a boss side to a holding ring side. Is shortened. Accordingly, the high-pressure airflow on the boss side allows the suction airflow from the suction inlet of the fan casing to be blown out of the blades near the holding ring without being separated, thereby improving the blowing performance of the sirocco fan.

[0008]

The invention according to claim 1 of the present invention has an impeller in a fan casing, the impeller constituting the impeller is formed in a blade cross-sectional shape, and the boss side thereof With a configuration in which the blade arc length is reduced stepwise on the holding ring side, the high pressure airflow on the boss side allows the suction airflow from the fan casing suction port to be blown out of the blades near the holding ring without peeling off. It has the effect of improving the fan blowing performance.

According to a second aspect of the present invention, there is provided an impeller in a fan casing, wherein the impeller constituting the impeller is formed in a blade cross-sectional shape, and the impeller is located closer to the holding ring than the boss. With the configuration in which the blade arc length is gradually shortened, the pitch of the blades is not constant and the wind is not sent out at the same cycle in addition to the effect of the invention of claim 1, so that the sound (nz) caused by the number of blades and the number of rotations Sound) does not occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

Embodiment 1 FIG. 1 is a side view of a sirocco fan according to Embodiment 1 of the present invention, in which a fan casing is cut. In FIG. 1, the sirocco fan performs an action of improving the air blowing performance, and is constituted by an impeller 1 having a blade 1a having an arc length reduced stepwise on the holding ring 4 side from the fan casing 2 and the boss portion 5. ing. Thereby, the high-pressure airflow on the boss portion 5 side allows the suction airflow from the suction port of the fan casing 2 to be blown out of the blade 1a near the holding ring 4 without being separated, thereby improving the blowing performance of the sirocco fan. Have.

FIG. 3 is a side view of a sirocco fan according to a second embodiment of the present invention, in which a fan casing is cut. In FIG. 3, the sirocco fan has the function of improving the air blowing performance, and is constituted by an impeller 6 having a blade 6a whose arc length is reduced stepwise on the holding ring 4 side from the fan casing 2 and the boss portion 5. ing. Accordingly, in addition to the operation of the first embodiment of the present invention, since the pitch of the blades is not constant and the wind is not sent out at the same cycle, a sound (nz sound) caused by the number of blades and the number of rotations is not generated. Having.

[0013]

As described above, according to the present invention, by changing the arc length of the blade in multiple steps, the suction air flow from the fan casing suction port is separated from the blade near the retaining ring by the high pressure airflow on the boss side. Since the air can be blown out without blowing, the blowing performance can be improved.

Also, by gradually changing the arc length of the blades, in addition to the above-described effects, the pitch of the blades is not constant and the wind is not sent out at the same cycle. nz sound) does not occur.

[Brief description of the drawings]

FIG. 1 is a side view showing a cross section of a fan casing of a sirocco fan according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a sirocco fan according to the first embodiment of the present invention.

FIG. 3 is a side view showing a cross section of a fan casing of a sirocco fan according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a sirocco fan according to a second embodiment of the present invention.

FIG. 5 is a side view showing a cross section of a fan casing of a conventional sirocco fan.

FIG. 6 is a front view showing a cross section of a fan casing of a conventional sirocco fan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 1a Blade 2 Fan casing 3 Bell mouth 4 Retaining ring 5 Boss part 6 Impeller 6a Blade 7 Impeller 7a Blade

Claims (2)

[Claims] An end of a plurality of blades arranged in a ring in a fan casing is held by a holding ring, a boss is provided at the center of the blade, and the arc length of the blade is gradually increased from the boss to the holding ring. Sirocco fan with shorter version. 2. A plurality of blades arranged annularly in a fan casing are held at both ends by a holding ring, a boss is provided at the center of the blade, and the arc length of the blade is gradually increased from the boss side to the holding ring side. Sirocco fan shortened.