JPS6147998B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roof fan that is of low noise type and is less affected by reaction force generated by exhaust gas.

As a conventional roof fan, one using a propeller fan is known. however,
Conventional roof fans like this have a large whining sound determined by the number of blades and the rotation speed, and noise caused by the high rotation speed, and propeller fans that can only maintain a small static pressure. It had its own particular drawbacks.

A roof fan using a centrifugal fan (for example, a multi-blade fan) eliminates these drawbacks. However, with such a roof fan, the air inside the building is sucked in from the center of the fan and is discharged straight into the atmosphere from an outlet provided on the outer periphery of the fan. Therefore, the exhaust direction from the discharge port is in the circumferential direction of the fan, and a large reaction force acts on the roof fan to rotate itself in the opposite direction to the exhaust direction. Therefore, it was necessary to increase the strength of the roof fan mounting part in consideration of the influence of the reaction force. Moreover, since the fan exhausts air straight in the circumferential direction, it sometimes becomes impossible to exhaust air smoothly due to the influence of atmospheric winds.

The present invention has been made in view of the above circumstances. That is, the roof fan according to the present invention includes a casing in which a suction port is provided on the lower side and a plurality of discharge ports opening in the circumferential direction are provided in the side surface rotationally symmetrically with respect to the vertical central axis, and each of the casings An arc-shaped plate member is attached between the outside of the discharge port and the outer circumferential surface of the casing in the opening direction of the discharge port, and forms a windbreak chamber that opens symmetrically in the vertical direction. The structure consists of an impeller that is rotatable around a central axis and sends air in the radial direction when rotated, and a drive mechanism that rotates this impeller, thereby reducing the amount of air generated by exhaust gas. To provide a roof fan that is less affected by reaction force and less susceptible to wind effects.

Hereinafter, one embodiment of the present invention will be described in Figures 1 to 3.
This will be explained with reference to the figures. 1 in the figure is the casing,
A suction port 2 is provided below it. This casing 1 has its suction port 2 connected to a roof opening 3 of a building.
It is installed on the roof according to the following. The casing 1 as a whole is rotationally symmetrical by 180 degrees with respect to the central axis O. Two discharge ports 4 are formed in each side of the casing 1. Further, the side wall 5 of the casing 1 has a spiral shape that is gradually spaced apart from the center axis O from the inside of one (the other) outlet 4 to the outside of the other (one) outlet 4. Also, casing 1
Arc-shaped plates 6 extending from the outside of the discharge port 4 to a predetermined location on the side wall 5 of the casing 1 are attached to the outside of the side wall 5 of the casing 1, thereby forming windbreak chambers 8 each having an opening 7 at the top and bottom. It is formed. A rotating shaft 9 is installed inside the casing 1 so as to coincide with the central axis O.
An impeller 10 is attached to this rotating shaft 9. The impeller 10 consists of a plurality of blades 11 provided parallel to the rotating shaft 9 and at intervals in the circumferential direction, and upper and lower ring plates 12 to which these blades 11 are fixed. Motor 1 is installed on the top of casing 1.
8 is attached, and this motor 13 is connected to the rotating shaft 9. Further, the motor 13 is covered by a motor cover 15 having a ventilation hole 14. An L-shaped pipe 16 is installed inside the ventilation hole 14.
is installed. Note that 17 is a ventilation hole provided in the upper part of the casing 1, whereby the inside of the motor cover 15 and the inside of the casing 1 are communicated with each other. Moreover, 18 is a bell mouth, and the discharge side and suction side in the casing 1 are cut off by this.

Next, the operation of the roof fan having the above configuration will be explained. When the motor 13 is driven to rotate the rotary shaft 9 and the impeller 10, as the impeller 10 rotates, the air between the blades 11 and in the vicinity of the blade 11 moves as shown by the arrow in FIG. As a result, the pressure inside the impeller 10 decreases, and the air containing dust inside the building is discharged from the roof opening 3.
and flows into the impeller 10 via the suction port 2,
This inflowing air then flows through the side wall 5 of the casing 1.
It moves along the arrows in FIG. 1 and is discharged from the discharge port 4 into the wind protection chamber 8, and further discharged into the atmosphere from the upper and lower openings 7.

At this time, outside air flows into the motor cover 15 through the pipe 16 and further into the impeller 10 through the ventilation hole 17, thereby ventilating the inside of the motor cover 15 and removing heat generated by the motor 13 itself. Temperature rise is suppressed.

Furthermore, even if there is a strong wind outside the building, the presence of the windbreak chamber 8 prevents wind pressure from being applied to the outlet 4, so that exhaust air from the outlet 4 can be carried out smoothly.

In this way, since a centrifugal fan is used,
Since the humming and noise can be suppressed to a very low level and a large static pressure can be obtained, the air inside the building can be exhausted to a desired location by connecting ducts. Note that if a sound absorbing material such as glass wool is attached to the inside of the windbreak room 8, the noise from the fan and the noise inside the building can be prevented from leaking to the outside.

Furthermore, since the roof fan with the above configuration is rotationally symmetrical at 180 degrees with respect to the central axis O,
The load due to the roof fan's own weight is uniformly applied to the fan attachment part A, and since the roof fan exhausts air from the upper and lower openings 7 of the windbreak chamber 8 in a well-balanced manner, the reaction force generated by the exhaust air hardly acts on the roof fan. Therefore, there is no need to make the roof fan attachment part A and the roof opening 3 particularly strong.

Further, in the above embodiment, two discharge ports 4 are provided in the casing 1, but the number is not limited to this, and the number may be three or four, for example.The point is that the casing 1 is rotated about the central axis. It should be symmetrical.

Further, in the above embodiment, a direct-coupled motor is used as the drive mechanism, but the present invention is not limited to this, and for example, a belt-hung type motor may be used.

As explained above, the roof fan according to the present invention has a windbreak chamber formed by an arc-shaped plate material, and is configured to divide the exhaust direction into two symmetrically in the direction of the rotation axis of the fan. The reaction forces caused by the exhaust gas thus generated cancel each other out in the direction of the rotation axis of the fan, and the influence of the reaction forces on the roof fan itself can be reduced. Therefore, there is no need to increase the strength of the attachment part of the roof fan, and the roof fan can be easily installed at low construction costs. Moreover, since the plurality of discharge ports are provided rotationally symmetrically with respect to the central axis of the casing, a load is applied to the attachment portion of the roof fan in a well-balanced manner, and it is possible to avoid the occurrence of uneven stress on the attachment portion.

Furthermore, since the arc-shaped plate covers the discharge port, exhaust can be smoothly discharged without being affected by wind.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional plan view showing one embodiment of a roof fan according to the present invention, FIG. 2 is a longitudinal cross-sectional view taken along the line --- in FIG. 1, and FIG. 3 is a perspective view showing the casing thereof. 1...Casing, 2...Suction port, 4...Discharge port, 13...Motor.

Claims (1)

[Claims] 1. A casing 1 having a suction port 2 on the lower side and a plurality of discharge ports 4 opening in the circumferential direction on the side surface, rotationally symmetrical with respect to a central axis in the vertical direction;
An arcuate shaped windbreak chamber 8 is attached between the outside of each discharge port 4 of this casing 1 and the outer peripheral surface of the casing 1 in the opening direction of the discharge port 4 and opens symmetrically in the vertical direction. Board material 6
, an impeller 10 that is rotatably provided inside the casing 1 around the central axis of the casing 1 and sends air in the radial direction when rotated, and a drive mechanism 13 that rotates the impeller 10. A roof fan characterized by: