JPH10220398A - Casing of a centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance and efficiency of a blower, and suppress generation of noises by making unstable flow from an outlet of an impeller collide with a projected rectifying plate, finely dividing spiral flow of the air, and performing rectification. SOLUTION: An L-shaped projected rectifying plate 5 is arranged near a discharge port of a spiral casing 1 of a centrifugal blower, perpendicularly to a flow passage and a casing mirror plate 4. Air flow is suctioned from a suctioning nozzle 6 on a front surface of an impeller, and flowed along the shape of a peripheral plate 3 of the spiral casing due to rotation of a multiblade impeller 2. Only a part of the air flow, showing maximum discharge velocity distribution, collides with the L-shaped projected rectifying plate 5 for suppressing generation of spiral flow. The air is introduced to a discharge port 7 of the centrifugal blower, and discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a casing of a centrifugal blower.

[0002]

2. Description of the Related Art A spiral casing provided with a suction nozzle in front of an impeller and a discharge port in the vicinity of a nose portion at the beginning of the spiral, and a rotatably mounted rotatably penetrating a spiral central portion on the back of the spiral casing. A shaft, a main plate, a side plate provided to face the main plate, and a number of blades interposed between peripheral edges of the main plate and the side plate, and an impeller mounted on the rotary shaft via a boss. The spiral start portion of the spiral casing is defined by a line passing through the spiral start portion at a position corresponding to the center of the rotary shaft and the side plate with respect to a line parallel to the center line of the discharge port passing through the center of the rotary shaft. The angle formed (optimal nose position angle) was constant, and a nose forming plate was provided at the spiral start end of the spiral casing according to the value. Therefore, the distribution of the discharge air velocity is not uniform, and it is difficult to change the distribution. Therefore, in the vicinity of the discharge port, a vortex that tends to cause performance degradation is generated, causing noise,
There is a drawback that the wind speed distribution at the discharge port has a considerable difference between the end plate side and the discharge side of the spiral casing.

[0003] Further, in a blower used for cooling a transformer coil or the like, a difference in cooling effect occurs if the discharge wind speed distribution is not uniform. Therefore, it is strongly required that the blower itself has a uniform discharge wind speed. .

A known example close to the invention is disclosed in Japanese Patent Application Laid-Open No. 4-350400.

[0005]

In the prior art, no consideration has been given to making the wind speed distribution of the discharge ports uniform, and there are problems such as deterioration of the blower characteristics and generation of noise due to the generation of the vortex. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a centrifugal blower having two sides to collide with a vortex of an air flow near a discharge port of a spiral casing to make the air flow subdivided and to eliminate unpleasant noise and to make the wind speed distribution uniform. By providing a symmetrical L-shaped protrusion straightening plate on the surrounding plate of the spiral casing, unsteady flow from the impeller outlet collides with the projecting straightening plate, subdivides the vortex of the air flow and eliminates annoying noise. In addition, the blower characteristics are improved and noise is suppressed.

[0007]

In order to achieve the above-mentioned object, the present invention provides a centrifugal blower using a multi-blade impeller, in which a wind speed distribution at a discharge port portion of a spiral casing is made uniform.
To subdivide the eddy of the air flow and eliminate harsh noise,
An L-shaped protrusion-shaped current plate having two sides symmetric was provided near the discharge port.

The shape of the L-shaped protruding straightening plate is confirmed by performing a confirmation test for obtaining an optimal straightening plate with a cooling fan of a main converter for a Shinkansen train supplied by a certain passenger railway company. Proven achievements. Also, the L-shaped projecting rectifying plate has a two-sided symmetrical L-shaped shape near the discharge port of the spiral casing, and causes the unsteady flow from the impeller outlet to collide with the rectifying plate to reduce the vortex of the air flow. By eliminating the subtle and unpleasant noise, the air flow is rectified, so that the characteristics of the blower can be improved and the noise generation can be suppressed and the noise can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. The spiral casing discharge part of the centrifugal blower is provided with a three-dimensional symmetrical L-shaped projection rectifying plate which is substantially parallel to the peripheral plate portion located at right angles to the flow path and the end plate.
The flow straightening plate has two sides of the L-shape equal and symmetrical, and the L-shaped right-angled part is located on the peripheral plate located L = 30 CM inside the spiral casing discharge port of the centrifugal blower. It is arranged so as to be a projection with respect to the flow path.
The unsteady flow from the exit of the impeller collides with the current plate, and the vortex of the air flow is finely broken by the projection, and the small vortex disappears. This means that the size of the vortex (vortex) of the air flow is reduced, the generated noise can be suppressed low, and the overall efficiency of the centrifugal blower is also improved by the L-shaped projection rectifying plate.
Since the vortex of the air flow is rectified and the static pressure of the blower of the blower characteristic is increased, the efficiency is greatly improved.

As an embodiment, an electric blower for cooling a main conversion device for a Shinkansen train delivered to a certain passenger railway company has an L-shaped projection rectifying plate provided on a spiral casing of a centrifugal blower. FIG. 3 shows the influence of the blower characteristics by the L-shaped projection straightening plate of the present invention. With the static pressure of the blower, L
If the U-shaped protrusion straightening plate is not provided, the specification blower air volume 80M3
/ MIN, 90 MMAQ (882 Pa), but with
It can be seen that it has improved by 1.1%. In addition, unpleasant wind noise disappeared, noise generation was suppressed, and noise reduction was demonstrated. In addition, the member of the L-shaped projection straightening plate adopted as the example used L20 × 20 × 3 isosceles angle steel (angle material).

[0011]

According to the present invention, in an air blower of a centrifugal blower, particularly a multi-blade impeller, an L-shaped projection straightening plate is arranged near the discharge port of the spiral casing.
Blower static pressure of the blower characteristics is improved by 11.1%,
It was confirmed that the blower efficiency also improved. This means
A stable, high-efficiency centrifugal blower is obtained.

[0012] Also, in terms of noise, the vortex of the air flow is subdivided to eliminate harsh noise, thereby rectifying the air flow and suppressing the generation of noise. can get.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a centrifugal blower having an L-shaped protrusion straightening plate near a discharge casing of a centrifugal blower spiral casing of the present invention.

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a characteristic diagram of a blower as an effect according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... spiral casing, 2 ... multi-blade impeller, 3 ... peripheral plate, 4
... head plate, 5 ... L-shaped projection straightening plate, 6 ... suction nozzle,
7 ... Discharge port.

Claims (1)

[Claims] 1. A spiral casing for a centrifugal blower,
A centrifugal blower casing comprising an L-shaped projection straightening plate provided near a casing discharge port to prevent eddy currents, improve blower performance and efficiency, and suppress noise generation.