JPH05280492A - Centrifugal blower - Google Patents

Abstract

PURPOSE:To obtain a centrifugal blower which can increase the perfectly closed static pressure, increase the wind quantity in static pressure operation and can reduce noise. CONSTITUTION:A recessed part 19 is formed at the near center part of the base plate 17 of a centrifugal blade 16, and a bulging-out part 20 which projects in the recessed part 19 is formed on the innermost wall 13 of a casing 12 opposed to the recessed part 19, and the inflow of the air sucked into the casing 12 to the reverse side of the centrifugal blade 16 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan used for a duct ventilation fan, an air conditioning ventilation fan and the like.

[0002]

2. Description of the Related Art A centrifugal blower used as a blower for a conventional duct ventilation fan, air-conditioning ventilation fan, etc., has a recess 5 formed in a substrate 4 of a centrifugal blade 3 as shown in FIG. The recess 5 is configured to act as a guide plate in order to make the flow of the intake air discharged by the centrifugal force of rotation efficient. Therefore, the recess 5 and the casing 1
A large space A having a shape corresponding to the depression 5 is formed between the flat wall 2 and the inner wall 2.

[0003]

In the centrifugal fan having the above structure, part of the air that has flowed in from the intake opening 6 of the casing 1 during the air blowing operation flows into the space A as indicated by arrow B, and is completely closed. There is a problem that the pressure becomes small, the air volume at static pressure becomes small, and the noise becomes large.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and the purpose thereof is to:
A centrifugal blower that can increase the fully closed static pressure by forming a recess in the base plate of the centrifugal blade and forming a bulge protruding into the recess on the back wall of the casing To provide.

[0005]

SUMMARY OF THE INVENTION A centrifugal fan according to the present invention includes a casing having an intake opening on one side and a discharge port on the other side, and a centrifuge arranged in the casing and rotationally driven by a motor. And a recessed portion projecting toward the motor side is formed at substantially the center of the substrate located on the side opposite to the motor of the centrifugal blade, and the recessed portion is formed in the back wall of the casing facing the recessed portion. It is characterized in that a bulge portion protruding to the side is formed. In this case, the bulging portion of the casing may be formed in a shape similar to the hollow portion of the centrifugal blade.

[0006]

When the centrifugal blade is driven to rotate, air is sucked by the centrifugal blade and discharged from the discharge port (not shown) of the casing. In this case, the inflow of air to the back side of the substrate of the centrifugal blade is prevented as much as possible.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to FIGS.
Will be described.

Reference numeral 11 denotes a main body of, for example, a ventilation fan for a duct having an exhaust port (not shown) on one side, and a casing 12 inside.
The casing 12 has an intake opening 14 formed on one side surface on the side opposite to the rear wall 13. A centrifugal blade 16 that is driven to rotate by a motor 15 is arranged in the casing 12 so that the substrate 17 is located on the back wall 13 side of the casing 12, that is, on the side opposite to the motor 15, and the substrate 17 is substantially omitted. A recess 19 is formed in the central portion so as to project to the blade piece 18 side, that is, the motor 15 side.

A bulging portion 20 is integrally formed on the back wall 13 of the casing 12 facing the dent portion 19 so as to project into the dent portion 19, and the bulging portion 20 is formed in the dent portion 19. It is formed in a similar shape corresponding to the shape and the recessed portion 1
9 has an arrangement having a slight gap.

Reference numeral 21 denotes an intake opening portion 1 of the casing 12.
4 is a motor mounting plate attached to the main body 11 so as to close the motor 4, and the motor base 22 holding the motor 15 is mounted on the bell mouth 23 so as to face the centrifugal blade 16.
Is formed. Next, the operation of the above configuration will be described.

When the centrifugal blade 16 is rotationally driven by the motor 15, air is sucked into the casing 12 through the bell mouth 23, and the air is discharged by the centrifugal blade 16 into the discharge port of the casing 12 and then the exhaust port of the main body 11. (None of them are shown). In this case, the bulging portion 20 of the casing 11 prevents the air sucked into the casing 12 from flowing into the back side of the centrifugal blades 16 as much as possible.

FIG. 2 shows the total closed static pressure in the centrifugal fan according to the present invention and the conventional closed-air blower as well as the total closed static pressure of 500 m ³ /
It shows that the measured values of "H type" are compared. According to the centrifugal fan of the present invention, both the total closed static pressure and the air volume at static pressure are increased as compared with the conventional centrifugal fan. .

The present invention is particularly effective for equipment such as the duct ventilation fan of the above-mentioned embodiment, which is connected to a duct (pipe), but is not limited to the duct ventilation fan, and a centrifugal blade of this type can be used. It can be widely applied to the possessed devices.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and the bulging portion does not necessarily have to be formed integrally with the casing. A configuration in which a bulging portion made of a member is provided, or a configuration in which the whole or a part of the inner wall of the casing is also used by the main body 11 and the main body 11 is provided with an integral or separate bulging portion may be used. The present invention can be appropriately modified and implemented without departing from the scope of the invention.

[0015]

As is apparent from the above description, according to the present invention, a hollow portion projecting toward the motor is formed in the substantially central portion of the substrate located on the side opposite to the motor of the centrifugal blade, and the hollow portion faces the hollow portion. By forming a bulging part that protrudes into the hollow part on the back wall of the casing, it is possible to prevent the air sucked into the casing from flowing into the back side of the centrifugal blade as much as possible, and increase the total closing static pressure. Therefore, it is possible to increase the air volume at the time of static pressure and to reduce the noise, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a diagram showing measured values of a fully closed static pressure and an air volume at static pressure in the centrifugal fan of the present invention and the related art

FIG. 3 is a diagram corresponding to FIG. 1 showing a conventional centrifugal blower.

[Explanation of symbols]

 12 Casing 13 Back Wall 16 Centrifugal Blade 17 Substrate 19 Throttling Section 20 Swelling Section

Claims (2)

[Claims] 1. A centrifugal machine comprising a casing having an intake opening on one side and a discharge port on the other side, and a centrifugal blade arranged in the casing and driven to rotate by a motor. A dent protruding toward the motor is formed in the substantially central portion of the substrate located on the side opposite to the motor of the blade, and a bulge protruding inside the dent is formed on the back wall of the casing facing the dent. Centrifugal blower characterized by that. 2. The centrifugal blower according to claim 1, wherein the bulging portion of the casing is formed in a shape similar to the shape of the hollow portion of the centrifugal blade.