JPH0614496U - Blower - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce noise in a blower with a built-in drive motor without causing problems such as an increase in frictional resistance of air and a decrease in flow rate. [Structure] The casing 1 has a substantially cylindrical shape, a suction port 2 is provided on the front surface thereof, and a spiral chamber 3 is formed at the rear portion thereof. A drive motor 5 is arranged in the casing 1. The rotary shaft 5 a of the drive motor 5 includes an impeller 10 located in the spiral chamber 3. A silencer 11 made of a porous plate having air permeability is provided in front of the suction port 2 at a predetermined interval.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a blower used for supplying combustion air in an industrial furnace and for carrying air.

[0002]

[Prior art]

 This type of blower is classified into an indirect drive type using a belt or a chain depending on the drive system, and a direct drive type in which an impeller is directly connected to a drive motor. Of these, the present invention is intended for a direct drive type. Furthermore, in the case of a direct-drive type blower, the type that sucks air from the front side of the impeller side of the drive motor is generally used. Intended. Such a blower with a built-in drive motor has a casing having a substantially cylindrical shape, a suction port provided at the front surface thereof, and a swirl chamber formed at the rear thereof, and a drive motor arranged in the casing. An impeller provided on the rotary shaft of the drive motor and located in the above-mentioned swirl chamber.

[0003]

[Problems to be solved by the device]

 According to the conventional blower with a built-in drive motor, the noise generated in the casing is repeatedly reflected as a sound wave on the inner wall of the casing and is emitted to the outside from the suction port, which causes a noise problem. Further, it is known that glass wool is attached to the inside of the casing in order to prevent such noise, that is, to reduce noise. However, in order to obtain a sufficient noise prevention effect only with glass wool, its thickness must be increased, which increases the frictional resistance of air and decreases the flow rate ratio. Invite.

Therefore, the present invention has been made to solve the above-mentioned problems, and its purpose is to avoid problems such as an increase in frictional resistance of air and a decrease in flow rate ratio in a blower with a built-in drive motor. The purpose is to provide a fan that can reduce noise.

[0005]

[Means for Solving the Problems]

 The blower of the present invention for solving the above-mentioned problems includes a casing having a substantially cylindrical shape, a suction port provided at the front surface thereof, and a spiral chamber formed at the rear portion thereof, and a drive motor arranged in the casing. In a blower with a built-in drive motor that is provided on the rotary shaft of the drive motor and has an impeller located in the swirl chamber, a silencer formed of a porous plate with air permeability is provided at a predetermined interval in front of the suction port. Are separated from each other.

[0006]

[Action]

 According to the above means, the noise generated in the casing of the blower with a built-in drive motor is repeatedly reflected as a sound wave on the inner wall of the casing, and tends to be emitted to the outside from the suction port. However, the energy of sound due to noise is attenuated by being converted into thermal energy by the viscosity of the air remaining in the holes of the silencer made of a porous plate while passing through the holes. Further, the air sucked into the casing is sucked into the suction port with almost no resistance through the space between the suction port and the silencer, which are separated from each other by a predetermined distance.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. A cross-sectional view of the blower is shown in FIG. 1, a front view of the blower is shown in FIG. 2 (a), and a side view thereof is shown in FIG. 2 (b). 1 and 2, the casing 1 is formed in a substantially cylindrical shape, a suction port 2 is opened in the front surface thereof, and a spiral chamber 3 is formed in the rear portion thereof. A discharge port 4 having an opening on the upper surface is provided on a side portion of the spiral chamber 3. The casing 1 of this example is made of a steel plate material. In addition, according to the casing 1 made of such a steel plate, the degree of freedom in shape, size, etc. is greater than that of the casing made of cast metal, and therefore it is advantageous to obtain a blower having a size according to the specifications and good blowing efficiency. .

A drive motor 5 is supported in the casing 1 by a support base 6 so as to be located on substantially the same axis. A general-purpose product can be used for the drive motor 5. The support base 6 has a lower end portion which can penetrate the bottom portion of the casing 1 and can be installed on the blower installation surface 7, and also serves as a support for the casing 1.

The rotary shaft 5 a of the drive motor 5 projects toward the spiral chamber 3. A rotor 8 is provided at the tip of the rotating shaft 5a. The rotor 8 is composed of a boss 9 fixed to the rotating shaft 5a, and an impeller 10 arranged on the boss 9 and rotated in the spiral chamber 3 by the rotation of the rotating shaft 5a.

In front of the casing 1, a disc-shaped silencer 11 formed of a porous plate having air permeability made of, for example, an aluminum powder sintered body is provided at a predetermined interval. That is, the silencer 11 is attached to the front plate 1a of the casing 1 through a proper number of substantially Z-shaped supporting pieces 12 so as to be substantially in the same axis as the suction port 2. The periphery of the mounting portion of the silencer 11 is shown in a sectional view in FIG. The silencer 11 has an outer diameter larger than that of the suction port 2. Therefore, between the support pieces 12 between the front plate of the casing 1 and the silencer 11, a space portion 13 communicating with the suction port 2 from the outside is formed.

An air filter 14 is attached to the front surface of the casing 1 so as to surround the silencer 11. The air filter 14 includes a frame member 15 fixed to the front surface of the casing 1, a cover plate 16 fixed to the frame member 15 and covering substantially the front surface of the casing 1, and an outer periphery of the frame member 15. The filter material 17 is made of, for example, nylon felt. Further, as shown in FIG. 1, sound absorbing materials 18 and 19 made of, for example, glass wool are mounted inside the casing 1 and inside the rear plate of the spiral chamber 3.

In the blower with a built-in drive motor configured as described above, when the drive motor 5 is actuated, the impeller 10 rotates, and the suction force thereof causes the outside air to pass through the filter material 17 of the air filter 14 and the suction port. Enter the casing 1 from 2. The air that has entered the casing 1 passes through the outer peripheral portion of the drive motor 5 and then enters the swirl chamber 3, where it is pressurized and discharged from the discharge port 4.

By the way, the noise generated in the casing 1 is repeatedly reflected as an acoustic wave on the inner wall of the casing, and tends to be emitted from the suction port 2 to the outside. However, the sound energy due to noise is attenuated by being converted into heat energy by the viscosity of the air remaining in the holes of the silencer 11 made of a porous plate while passing through the holes. To be

As a result of comparative measurement of noise between the blower provided with the silencer 11 and the blower without the silencer 11, a characteristic diagram as shown in FIG. 4 was obtained. In FIG. 4, the horizontal axis represents frequency, and the vertical axis represents noise, which is equivalent to 1 dB (A) [at 1.0 m] per scale. The solid line shows the noise of the blower with the silencer 11, and the dotted line shows the noise of the blower without the silencer 11. As is clear from FIG. 4, the fan with the silencer 11 has a lower value of about 1.5 dB (A) [at 1.0 m] than the fan without the silencer, and especially at 2000 Hz. A low value of 2.5 dB (A) [at 1.0 m] was also obtained.

Further, as shown in FIGS. 1 and 3, the air sucked into the casing 1 passes through the space portion 13 between the suction port 2 and the silencer 11 which are separated from each other by a predetermined distance to the suction port 2. It is sucked with almost no resistance.

The sound absorbing materials 18 and 19 mounted inside the casing 1 are selected to have a thickness that does not adversely affect the frictional resistance of air and the flow rate ratio, and together with the silencer 11, reduce noise. It is valid. Further, the air filter 14 provided on the suction port 2 side removes dust contained in the air sucked into the casing 1. The sound absorbing materials 18, 19 and the air filter 14 do not influence the gist of the present invention.

[0017]

[Effect of device]

 According to the present invention, of the noise generated inside the blower with a built-in drive motor, the noise emitted from the suction port of the casing is attenuated without causing problems such as increase in friction resistance of air and decrease in flow rate. As a result, the noise of the blower can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a blower.

FIG. 2 is an external view of a blower.

FIG. 3 is a sectional view of a main part of a blower.

FIG. 4 is a characteristic diagram showing a relationship between a blower frequency and noise.

[Explanation of symbols]

 1 Casing 2 Suction Port 3 Swirl Chamber 5 Drive Motor 5a Rotating Shaft 10 Impeller 11 Silencer

Claims (1)

[Scope of utility model registration request] 1. A casing having a substantially cylindrical shape, a suction port provided in the front surface thereof, and a spiral chamber formed in the rear portion thereof, a drive motor arranged in the casing, and a rotary shaft of the drive motor. In a blower with a built-in drive motor provided with an impeller located in the swirl chamber, a blower in which a silencer formed of a porous plate having air permeability is provided at a predetermined interval in front of the suction port. .