JPS6043199A - Reduction of noise of fan - Google Patents

Abstract

PURPOSE:To reduce the noise of a fan by a method wherein the position of installation of a runner in a duct is made movable into the axial direction of the duct relatively with respect to the duct and the position of installation of the runner is followed and moved by detecting the noise of the fan to a position whereat the noise of the same becomes minimum. CONSTITUTION:When a servomotor 5 is rotated into either one of normal or reverse directions, the rotating motion is converted into a linear motion of a head 3 in the axial direction thereof through a screw rod 6 and the protuberance 4 of the head 3 to advance or retreat the head 3 of the runner 2 through the inside of the duct 1. Under the process of movement of the head 3 from one end to the other end, the noise of the fan is detected by a microphone (e) to send the signal of detection into a memory circuit (g) sequentially, the position of the heat, whereat the noise of the fan is minimum, is selected and extracted by the minimum value discriminating circuit (h) from the memorized data, the input signal component is sent to a program selecting and commanding circuit (b) and the circuit inputs the signal component into a selsyn I, outputting a driving signal for driving the servomotor 5, based on the signal. As a result, the head 3 is moved to and held at the optimum position whereat the noise of the head 3 becomes minimum and thereby reducing the noise of the fan.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing the noise of a blower in order to prevent noise pollution and improve the working environment.

Hitherto, silencers have been widely used to reduce blower noise, but if you try to use this silencer to effectively silence the blower, there will be resistance to the wind flow, so the blower will not work properly. Performance may deteriorate and undesirable conditions may occur.

On the other hand, noise reduction without using a silencer, Prevention 1! A method of controlling the rotation speed of a friend as a force method (Unexamined Japanese Patent Publication No. +11153)
-75510 publication), a method of changing the rotation angle of multi-stage impellers (see Japanese Patent Application Laid-open No. 54-62509), or a method of changing the positional spacing of two stage impellers according to the wavelength of B. Method for applying membranes to
3746) etc. are known.

However, with this method, there are certain restrictions regarding the installation of the blowers and the installation of noise suppression means, such as the need to use multiple blowers, and it is not always possible to obtain the desired noise suppression effect. do not have.

Focusing on the fact that the noise of the blower fluctuates greatly depending on the pickup device inside the duct and the length of the duct, we developed a method for producing low-frequency noise without installing a silencer. Also, unlike the various methods that do not use a silencer,
The present invention aims to provide a method for reducing blower noise that has a reliable configuration in the cylinder.

In order to achieve the objective described in I-, the noise reduction method of the present invention includes:
In a blower with a blade wheel installed in the tact, 1- the installation position of the blade wheel in the duct with respect to the duct i.
It is designed to be relatively movable in the kl+ line direction, detect the blower noise, and move the installation position of (-) to the position where it is minimized.

The method of the present invention will be explained in detail below with reference to the drawings.

Figure 1 shows the relationship between the blower rotation speed and the magnitude of the noise i: ↑, using the take-up position of the wing bow t within the tact as a parameter. Using 15 blowers each, the distance from the person ``■'' of dak 1 to the center position of the friend is shown in the figure, and the noise when 1~LJ is /. As is clear from the above, a slight change of 15 mm in the pick-up position of the blade wheel causes a large change in the noise, and when the blade wheel is driven to rotate at a constant rotation speed, the noise level varies depending on the customer's choice of the mounting position of the blade wheel. In addition, the noise described in -1- also varies depending on the length of the duct, the restriction of the outlet 11, the load on the blower, etc.

Therefore, noise can be easily reduced by moving the blower's impeller within the duct to a position that minimizes noise, or by expanding or contracting the length of the duct to the length that minimizes noise. It becomes possible.

Figure i'52 shows an example of the structure of a blower that reduces noise as described in 1, in which the impeller 2 is movable in the axial direction within 1! 1411 This shows a JAf blower, in which a cylindrical vent 3 with a pipe 2 fixed therein is disposed in the duct 1 so as to be able to slide in the axial direction, and the protrusion 7 in the head 3 < R4
A driving screw rod 6 rotated by a servo motor 5
is screwed in so that it can be rotated. In the figure, 7.8 indicates a moving blade and a stator blade of the aircraft, and 9 indicates a motor that rotates the moving blade 7.

1- In the device described above, when the servo motor 5 rotates in either direction of the city road, the rotation causes the rod 6 and l.
This is converted into linear interlocking in the axial direction of the vent 3 through the protrusion 4 of the vent 3, thereby moving the blade 11 (2 and 3) forward and backward within the tact 1.

The motor 5 is driven by a signal V3 from a control circuit electrically connected to it, and the control circuit detects the noise i' of the blower and determines whether the noise is the minimum. It is configured to output a -1 which moves p II 2 to the position where p II is.

FIG. 3 shows an example of the above control circuit. In this control device, the human input signal sent to the program control circuit, the reverse rotation circuit, is 11'!, for example from a function generator or other suitable means. It is an electrical signal that increases or decreases depending on the direction, and its 1-limit and lower limit are determined by the bend 3 caused by the servo motor 5 in FIG. 2, as will be explained later.
It is made to correspond to the movement position of both ends. In addition, the above human power (
+-r 53 may be, for example, a digital signal 44'j that changes in a step-like manner every few seconds, or a signal that changes in an analog manner.

The Progera J-selection command circuit mentioned above is for manually inputting the input signal to Sershin CI) in accordance with the Progera L1 that has been omitted. Drive A, output No. 1-,
This is amplified by 'l'i+f in the amplifier to drive the servo motor 5, thereby driving the 21A Ben 1z3. Further, the position of the head driven in this way is fed-hacked via the Sershin (II), and the servo motor is driven so that the deviation from the output of the Sershin (I) becomes O. - As mentioned above, since the limit and the limit of the human power signal that increases or decreases in the application correspond to the positions of movement of both ends of the bed 3 by the servo motor 5, a series of input values is required. The vent 3 is moved within its movable range from one end to the other by driving the surf motor by the holder.

While the vent 2 is moving from one end to the other in this way, the noise of the feeder is detected by the microphone and sent to the unordered storage circuit. This memory circuit receives the input signal and stores the noise i'7 in correspondence with the input signal, so that while the vent moves within the movable range from one end to the other end, the noise i'7 is stored. The noise EX- at the outer position will be stored in the memory circuit.

The minimum 4ri HL separate circuit is 1- from the data stored in the storage circuit to the input corresponding to small noise.
It selects and extracts the J component, that is, the 4M device whose noise is small, and sends the input 4M component to the program selection command circuit. Fix the signal to be sent to the A1-1 component, which makes noise or +iB small.

As a result, the bet is moved to the optimum position where the noise is reduced and is held at that position.

The program selection command circuit has an internal timer,
An input signal that increases or decreases in rli tone every 11 jl intervals set in advance is sent to Sershin (I) to repeatedly perform the operation of searching for the minimum noise position as described above. The installation position of wing-1i is moved accordingly.

Note that the interval between μv for repeating the operation of searching for the minimum noise position can be set within the room depending on the use of the blower.

In 1-1 below, we have explained the case where the position of the impeller is moved within a duct of a certain length to reduce the noise level. In 1-1, the duct I is configured to extend and contract using a moving mechanism similar to that in this case, and the impeller is installed in the tact (<, the position is in the 1li11 line direction of the tact). It can also be moved relatively.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between fan rotation speed and noise level, Fig. 2 is a sectional view illustrating the configuration of a 111-stream blower embodying the present invention, and Fig. 3 is the operation of the above-mentioned imperial blower. FIG. 3 is a block configuration diagram of a control circuit that controls the . I・Work tact, 2・Kemata 11! ,.

Claims (1)

[Claims] l In a blower with small blades installed in the duct, the installation position of the L-shaped wheel in the tact can be moved relative to the duct in its axial direction, and the blower noise can be detected and detected. A method for reducing blower noise, characterized by moving the installation position of a blower to a position where it is minimized.