JP2002253991A - Centrifuge - Google Patents

Abstract

(57) Abstract: The present invention relates to a centrifuge active noise reduction control device for reducing the sound level of a noise source such as a compressor or a motor or a fan of a refrigeration cycle of a centrifuge,
An object of the present invention is to reduce the noise of a centrifuge by actively reducing the sound power emitted from a noise source for low-frequency noise that cannot be reduced by a passive silencer made of a sound absorbing material or the like. SOLUTION: An artificial additional sound source means 9 which forms a pair with a compressor 5 or a rotary driving device 2 or a cooling fan 13 as a noise source of a centrifuge and generates sound waves of the same amplitude and opposite phase with respect to the sound waves emitted by the noise source. And a sound wave detecting means 1 for receiving a sound wave emitted from the noise source and a sound wave emitted from the artificial additional sound source means 9
0, a noise source reference unit 11 that refers to noise information of only the noise source, and a control unit 12 that controls the artificial additional sound source unit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifuge active noise reduction control device for reducing the sound level of a noise source such as a compressor, a motor or a fan of a refrigeration cycle of a centrifuge.

[0002]

2. Description of the Related Art A main noise source of a centrifuge is a compressor or a motor or a fan of a refrigeration cycle. Whether or not each noise source can be driven is determined by the operation mode of the centrifuge, and the frequency and sound pressure of the noise of the centrifuge in which each noise is combined also changes depending on the operation mode of the centrifuge.

Conventionally, the method of reducing the noise when the noise source is driven has been a method of surrounding the noise source with a sound absorbing material or a method of attaching the sound absorbing material to the inside of a cover of the centrifuge. In general, the noise attenuation effect of a sound absorbing material depends on the thickness of the sound absorbing material, and the thicker the sound absorbing material, the more the sound absorbing effect from the low frequency range can be expected.However, when used in a limited space such as a centrifuge, There was a spatial limit of about 10 mm or less, and the frequency at which noise could be attenuated was about 1 kHz or more.

[0004]

The fundamental frequency of the noise of the compressor and fan of the refrigeration cycle is about 200 Hz. To reduce the noise of the centrifuge using the conventional sound absorbing material, the electromagnetic noise of the motor during high-speed rotation is reduced. However, there is a problem that a sufficient silencing effect can be obtained with respect to high-frequency noise, but such low-frequency noise cannot be muted. Also, if the fan provided in the centrifuge housing is a noise source to cool the equipment inside the centrifuge, sound is emitted from the fan to the outside of the centrifuge. There was a possible problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to actively reduce the sound power emitted by a noise source of a centrifuge,
An object of the present invention is to provide an active noise reduction control device for a centrifuge capable of reducing low-frequency noise.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a rotary drive for rotating a rotor for a centrifuge connected by a drive shaft, a bowl surrounding the surface of the rotor for the centrifuge, a refrigerant flow path, and a refrigerant passage. It has a condenser that condenses, a capillary that adiabatically expands the refrigerant and a compressor that circulates the refrigerant, and a pipe that contacts the bowl and cools the bowl, and a cooling fan that air-cools the compressor.The piping, condenser, capillary, and compressor In a centrifugal machine that constitutes a refrigeration cycle and rotates a centrifuge rotor that is rotationally driven by a rotational drive device while cooling by the refrigeration cycle, the compressor, the rotational drive device, or the cooling fan that is a noise source of the centrifuge is paired. The artificial additional sound source means for generating sound waves of the same amplitude and opposite phase to the sound waves emitted by the noise source, and the noise source emits This is achieved by providing a sound wave detecting unit that receives a wave and a sound wave generated by the artificial additional sound source unit, a noise source reference unit that refers to noise information of only the noise source, and a control unit that controls the artificial additional sound source unit. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a configuration of an active noise reduction control device for a centrifuge according to a specific embodiment of the present invention. In FIG. 1, 1 is a rotor for centrifuging a sample,
Reference numeral 2 denotes a rotary drive device for rotating the rotor 1 comprising a motor and a drive shaft for transmitting the rotational drive torque of the motor to the rotor 1. Reference numeral 3 denotes an air-cooled rotor surrounding the surface of the rotor 1, for example, aluminum having a high thermal conductivity. A pipe 4 for connecting a condenser 6 that serves as a flow path of the refrigerant, a condenser 6 that condenses the refrigerant, a capillary 7 that adiabatically expands the refrigerant, and a compressor 5 that circulates the refrigerant, and that contacts the bowl 3 and cools the bowl 3; Reference numeral 8 denotes a compressor room for storing the compressor 5. Reference numeral 9 denotes artificial additional sound source means, such as a loudspeaker, which forms a pair with the compressor 5 serving as a noise source and generates a sound wave having the same amplitude and opposite phase with respect to the sound wave radiated by the noise source. So that the noise can be reduced. Reference numeral 10 denotes a sound wave detecting means such as a microphone for receiving an interference wave between the sound wave emitted from the compressor 5 serving as a noise source and the sound wave emitted from the artificial additional sound source means 9, and a sound wave generated when only the artificial additional sound source means 9 is driven. At the position of the knot. Reference numeral 11 denotes a noise source reference means such as an acceleration pickup for detecting the vibration state of the compressor 5 or a current transformer for detecting a current of a motor for driving the compressor 5, which is a source of the noise of the compressor 5. With reference to the acoustic signal of the sound wave generated by the compressor 5 and the sound wave generated by the artificial additional sound source means 9 and the noise information of only the compressor 5 by the noise source reference means 11, the sound signal detected by the sound wave detecting means 10 is reduced. Control means for controlling the artificial additional sound source means 9;
This is realized by a signal processor (hereinafter referred to as DSP). Reference numeral 13 denotes a cooling fan provided in the centrifuge housing to cool the compressor 5 by air.

Next, the operation of the active silence control device for a centrifuge according to the present embodiment will be described with reference to FIG. In FIG. 2, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals. FIG. 2 is a block circuit diagram showing a detailed embodiment of the control means 12 for controlling the artificial additional sound source means 9 in FIG. In FIG. 2, reference numeral 21 denotes an A / D converter which samples an analog sound signal detected by the sound wave detecting means 10 and converts the signal into a digital value. Reference numeral 22 denotes an analog noise information signal detected by the noise source reference means 11 in a digital value. A / D converter for converting to
Reference numeral 3 denotes a transfer function for converting a noise information signal of the compressor 5 detected by the noise source reference means 11 obtained by experimental identification into an acoustic signal of the compressor 5 at the position where the noise source reference means 11 is installed. For example FIR in DSP
It can be expressed as a digital filter such as a filter. Reference numeral 24 denotes a spatial filter between the input of the artificial additional sound source means 9 and the output of the sound wave detecting means 10 obtained by an identification experiment in the same manner as 23, 26 denotes a so-called adaptive digital filter, and 25 denotes a coefficient of the adaptive digital filter 26. A coefficient correction algorithm based on the steepest descent method or the like for successive correction is provided. Reference numeral 27 denotes a D / A converter for converting a digital value output from the adaptive digital filter 26 into an analog signal.

Next, control of the coefficient correction algorithm 25 of the adaptive digital filter 26 in this embodiment will be described. Compressor 5 detected by noise source reference means 11
If the coefficient of the transfer function 23 and the coefficient of the adaptive digital filter 26 for converting the noise information of X into the acoustic signal of the compressor 5 at the installation position of the noise source reference means 11 are W, The input Y is Y = HWX, the output signal of the sound wave detecting means 10 when only the compressor 5 serving as a noise source is driven is e ₀ , and the signal between the input of the artificial additional sound source means 9 and the output of the sound wave detecting means 10 Assuming that the spatial filter coefficient is C, the output signal e of the sound wave detecting means 10 at the time of control, that is, at the time of simultaneous driving of the compressor 5 and the artificial additional sound source means 9, is e = e ₀ + CY = e ₀ + HCWX. Can be expressed. Here, since the control means 12 may control the artificial additional sound source means 9 so that the acoustic signal detected by the sound wave detection means 10 becomes zero, e can be considered as a control error. If the mean square value of the error e is Ep, then Ep = E (e ² ), and the gradient of Ep with respect to the coefficient W of the adaptive digital filter 26 is

[0010]

(Equation 1)

## EQU1 ## When the steepest descent method that updates the coefficient W in the direction opposite to the gradient of Ep is applied, the sampling time n +
The coefficient W (n + 1) of 1 is the coefficient at the previous sampling
By introducing the adaptation coefficient μ as (n), W (n + 1) = W (n) −μ · H · C · X · e.

Therefore, the coefficient correction algorithm 25 sequentially updates the coefficient W of the adaptive digital filter 26 so as to minimize the square value of the error e on average, and controls the artificial additional sound source means 9 to reduce the noise. obtain.

In this embodiment, each of the artificial additional sound source means 9 and the sound wave detecting means 10 has a single structure. However, the artificial additional sound source means 9 is a means for reducing the sound power emitted from the noise source, and is capable of detecting the sound wave. Since the position where the means 10 is installed can be regarded as a muffling point, the muffling effect can be increased by providing a plurality of artificial additional sound source means 9 and sound wave detecting means 10. The noise source of the centrifuge is a motor of the rotary drive 2, a cooling fan, and the like in addition to the compressor 5. As shown in FIG. Additional sound source means 9, sound wave detecting means 1
0, by installing the noise source reference means 11 and operating the control means 12 as described above to control the artificial additional sound source means 9, the noise of the centrifuge can be reduced. Also, the control unit refers to the acoustic signal of the sound source emitted by the sound source detecting unit 10 and the acoustic signal of the sound source emitted by the artificial additional sound source unit, and the noise information of only the noise source by the noise source reference unit, and detects the sound source. The artificial additional sound source is controlled while sequentially updating the coefficients of the adaptive digital filter so that the acoustic signal is minimized, so the acoustic power emitted by the noise source of the centrifuge is actively reduced to reduce low-frequency noise. can do.

[0014]

According to the present invention, a compressor or a rotary drive or a cooling fan serving as a noise source of a centrifuge is paired to generate a sound wave of the same amplitude and opposite phase with respect to the sound wave radiated by the noise source. Additional sound source means, sound wave detecting means for receiving sound waves emitted by the noise source and sound waves emitted by the artificial additional sound source means, noise source reference means for referring to noise information of only the noise source, and control for controlling the artificial additional sound source means By providing the means, the acoustic power emitted from the noise source of the centrifuge can be actively reduced, and low-frequency noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an active noise reduction control device for a centrifuge according to the present invention.

FIG. 2 is a block circuit diagram showing an active noise reduction control device for a centrifuge according to the present invention.

FIG. 3 is a schematic configuration diagram showing another active noise reduction control device of the centrifuge according to the present invention.

[Explanation of symbols]

2 is a rotary drive device, 5 is a compressor, 9 is an artificial additional sound source means, 10 is a sound wave detection means, 11 is a noise source reference means,
Reference numeral 12 denotes control means for controlling the additional sound source means, and reference numeral 13 denotes a cooling fan.

Claims (2)

[Claims] A rotary drive for rotating a centrifuge rotor connected by a drive shaft; a bowl surrounding the surface of the centrifuge rotor; a condenser for forming a refrigerant flow path and condensing the refrigerant; A pipe that connects a capillary that adiabatically expands the refrigerant and a compressor that circulates the refrigerant and contacts the bowl to cool the bowl, and a cooling fan that air-cools the compressor, the pipe, the condenser, and the capillary. In a centrifugal machine that constitutes a refrigeration cycle from the compressor and rotates a centrifuge rotor that is rotationally driven by a rotational drive device while cooling by the refrigeration cycle, the compressor or the rotational drive device or the cooling fan that is a noise source Artificial additional sound source means for generating sound waves of the same amplitude and opposite phase with respect to the sound waves emitted by the noise source in pairs with Sound wave detecting means for receiving sound waves emitted by the noise source and sound waves emitted by the artificial additional sound source means, noise source reference means for referring to noise information of only the noise source, and control means for controlling the artificial additional sound source means And a centrifuge. 2. The control unit refers to an acoustic signal of the sound source emitted by the noise source and the acoustic signal of the acoustic wave emitted by the artificial additional sound source unit and the noise information of only the noise source by the noise source reference unit. 2. The centrifuge according to claim 1, wherein said artificial additional sound source means is controlled such that an acoustic signal detected by said sound wave detecting means is reduced.