JP2014200736A - Low frequency sound reduction device by vibrational screening machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly reduce a low frequency sound generated by vibration of a vibration body, by accurately detecting the vibration of the vibration body of a vibrational screening machine, even if dust is generated.SOLUTION: The vibration body of the respective vibrational screening machines 1 and 3 is detected by non-optical proximity sensors 5a and 5b arranged in the vicinity of its vibration range, and a frequency phase difference detection part 11 detects vibration frequencies f1 and f2 of the respective vibration bodies and a phase difference θ of the vibration from its detection signal. A phase difference control part 15 calculates a control volume alpha for approaching the phase difference θ to a target phase difference based on a difference u2 between the phase difference θ of the vibration of the detected respective vibration bodies and a predetermined target phase difference. The calculated control volume alpha is added to the difference between the vibration frequencies f1 and f2 of the respective vibration bodies by an adder 17, and is inputted to a frequency control part 13. The frequency control part 13 outputs motor speed command voltage for reducing the difference between the vibration frequencies f1 and f2 of the respective vibration bodies detected by the frequency phase difference detection part 11.

Description

  The present invention relates to an apparatus for reducing low-frequency sound generated by a vibration sieving machine.

  2. Description of the Related Art Conventionally, there has been provided a vibration sieving machine that vibrates a vibrating body such as a sieve screen at a constant frequency by a vibration device and screens materials and the like on the vibrating body. In this vibration sieving machine, it has been a problem to reduce low-frequency sound generated by vibration of the vibrating body.

  One effective proposal for reducing low-frequency sound is to attenuate the low-frequency sound generated by the vibrating body of one vibrating screen machine by the low-frequency sound of a different phase generated by the vibrating body of another vibrating screen machine. There is something to let you. Therefore, in this proposal, the vibration of the vibrating body of each vibration sieving machine is detected by a known vibration sensor (for example, Patent Documents 1, 2, and 3).

Japanese Patent No. 2925540 Japanese Patent No. 3371209 JP 59-69548 A

  By the way, the vibration sieving machine is not only screened between muddy water and solid matter in excavation work using a muddy water pressurization type shield machine as described in Patent Documents 1 and 2, but also, for example, coal and wood chips, etc. It is also used for sieving. Since the generation of dust is inevitable with such material sieving, maintenance such as frequent cleaning of the sensor head is indispensable in order to accurately detect the vibration of the vibrating body with a known vibration sensor such as a laser distance meter. Absent.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to accurately detect the vibration of the vibrating body of the vibrating screen even in an environment where dust is generated, and to generate the vibration by the vibration of the vibrating body. An object of the present invention is to provide a low-frequency sound reduction device using a vibration sieve that can appropriately reduce low-frequency sound.

In order to achieve the above object, a low-frequency sound reducing device using a vibrating screen according to the present invention described in claim 1 is:
A device that reduces the low-frequency sound generated by the vibration of each vibrating body by a plurality of vibrating screens by mutual interference,
A non-optical proximity sensor for detecting the corresponding vibrating body, which is disposed in the vicinity of the vibrating range of the vibrating body of each vibrating screen machine and approaches within a detectable distance, or together with a vibration source of the vibrating body A proximity sensor that is arranged in a sealed state and detects a vibrator of the vibration source that is approached within a detectable distance; and
From the waveform of the detection signal of the vibrating body by each proximity sensor, detection means for detecting the vibration frequency and phase of the vibrating body for each of the vibrating screeners,
With respect to the vibration of the vibrating body of the one vibrating screen detected by the detecting means, the vibration of the vibrating body of the other vibrating screen detected by the detecting means has the same frequency and the low frequency. Based on the vibration frequency and phase of the vibrating body for each of the vibration sieves detected by the detection means so that a predetermined phase difference determined by the relative position difference with respect to the target point of frequency sound reduction is obtained, the other vibrations Control means for controlling the vibration of the vibrating body in the sieve machine;
It is characterized by providing.

  According to the low frequency sound reduction device using the vibration sieve of the present invention described in claim 1, when the vibration body that vibrates within the vibration range exists within the detectable distance, the vibration body is detected by the non-optical proximity sensor. Is detected. Alternatively, the proximity sensor disposed in a sealed state together with the vibration source of the vibrating body detects the vibrator of the vibration source that has approached within the detectable distance. For this reason, when detecting the vibrating body or the vibrator, the detection optical path is not blocked by the dust, the detection light is refracted, or the detection of the vibrator is prevented by the dust.

  Therefore, when controlling the vibration frequency and phase of the vibrating body of a vibrating sieve machine that performs sieving where generation of dust such as coal and wood chips is unavoidable, the vibration frequency and phase of the vibrating body must be accurately grasped. These control amounts can be accurately determined, and low frequency sound at the target point can be efficiently reduced.

Moreover, the low frequency sound reduction device by the vibration screener of the present invention described in claim 2 is the low frequency sound reduction device by the vibration screener of the present invention described in claim 1,
The control means is
When the vibration frequency of the vibration body of the other vibration screener is larger than a predetermined value with respect to the vibration frequency of the vibration body of the one vibration screener, the deviation of the vibration frequency is made smaller than the predetermined value. The vibration frequency control of the vibrating body is performed for the other vibration sieving machine,
The deviation of the vibration frequency of the vibration body of the other vibration screener with respect to the vibration frequency of the vibration body of the one vibration screener is smaller than the predetermined value, and the vibration of the vibration body of the one vibration screener When the phase difference of the vibration of the vibrating body of the other vibration sieving machine is more than a predetermined amount with respect to the predetermined phase difference, the phase difference is less than the predetermined amount. Perform the phase control of the vibration of the vibrating body for the other vibration sieving machine,
The deviation of the vibration frequency of the vibration body of the other vibration screener with respect to the vibration frequency of the vibration body of the one vibration screener is smaller than the predetermined value, and the vibration of the vibration body of the one vibration screener When the deviation between the vibration phase difference of the vibrating body of the other vibrating screener and the predetermined phase difference is smaller than the predetermined amount, the vibration frequency of the vibrating body of the one vibrating screener is set to the other frequency. The vibration frequency control for bringing the vibration frequency of the vibration body of the vibration sieve machine close to the other vibration sieve machine is performed.
It is characterized by that.

  According to the low-frequency sound reducing device by the vibrating screen of the present invention described in claim 2, in the low-frequency sound reducing device by the vibrating screen of the present invention described in claim 1, the vibrating body of one vibrating screen By appropriately selecting whether to give priority to vibration frequency control or vibration phase control according to the combination of the magnitude of the vibration frequency deviation of the vibrating body of the other vibration sieve machine and the magnitude of the phase difference of vibration In addition, it is possible to create a situation in which it is easy to bring the vibration phase difference between the vibrating bodies of both vibratory sieve machines close to the target phase difference by phase control.

  According to the low-frequency sound reduction device using the vibration sieve machine of the present invention, even in an environment where dust is generated, the vibration of the sieve screen is accurately detected and the low-frequency sound generated by the vibration sieve machine is appropriately reduced. can do.

It is explanatory drawing which shows the example of a position of the use environment of the vibration sieve which reduces a low frequency sound using the low frequency sound reduction apparatus which concerns on this invention. It is explanatory drawing which shows the example of arrangement | positioning of the proximity sensor which detects the vibrating body of the vibration sieve machine of FIG. It is a block diagram which shows schematic structure of the low frequency sound reduction apparatus which concerns on one Embodiment of this invention used in the use environment of the vibration sieve machine of FIG. (A), (b) is a graph which shows the example of a change of the displacement of the vibrating body in each vibration sieve machine of FIG. (A), (b) is a graph which shows the signal waveform which the proximity sensor of FIG. 2 corresponding to the displacement of each vibrating body shown to FIG. 4 (a), (b) outputs. (A) is a graph showing a change example of the displacement of the vibrating body of the vibration sieve machine, (b) is a change in the displacement of the vibrating body shown in (a) by the proximity sensor when the installation location of the proximity sensor in FIG. 2 is changed. It is a graph which shows the signal waveform output with respect to. (A) is a graph showing a change example of the displacement of the vibrating body of the vibration sieve machine, (b) is a change in the displacement of the vibrating body shown in (a) by the proximity sensor when the installation location of the proximity sensor in FIG. 2 is changed. It is a graph which shows the signal waveform output with respect to. It is a flowchart which shows the procedure of the process which the controller of FIG. 3 performs. It is explanatory drawing which shows the example of arrangement | positioning of the proximity sensor which detects the eccentric weight of the vibration source of FIG. It is a perspective view which shows the detailed structure of the eccentric weight of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing an example of the position of a use environment of a vibration sieve machine that reduces low frequency sound using the low frequency sound reduction device according to the present invention, and a proximity sensor that detects a vibrating body of the vibration sieve machine of FIG. It is explanatory drawing which shows the example of arrangement | positioning.

  The low-frequency sound reduction device according to the present invention, for example, as shown in FIG. 1, generates low-frequency sounds generated by the vibrating bodies 1a and 3a of the two vibrating screeners 1 and 3, respectively. Is used for reduction at a reduction target point A which is 1 or 2 away from each other.

  In order to detect the vibration frequency and phase of the vibrating bodies 1a and 3a of the vibrating screens 1 and 3, near the vibration range of the vibrating bodies 1a and 3a, as shown in FIG. A sensor 5 is arranged. The proximity sensor 5 changes its output from a low level (for example, 0 V) to a high level (for example, 1 V) when the vibrating bodies 1 a and 3 a that vibrate within the vibration range are approaching within the detectable distance of the proximity sensor 5. Change.

  Specifically, an inductive sensor, a capacitive sensor, a magnetic sensor, or the like can be used. However, when the induction type is used, it is necessary that the vibrating bodies 1a and 3a include a metal portion. Moreover, when using a magnetic system, it is necessary for the vibrating bodies 1a and 3a to contain a magnetic body.

  The vibrating bodies 1a and 3a of the vibration sieves 1 and 3 are vibrated using vibration sources 1b and 3b that generate vibrations by rotating the eccentric weight by a driving source such as a motor. Therefore, the trajectory when the vibrating bodies 1a and 3a vibrate is not necessarily linear, and may be an elliptical trajectory, for example. Therefore, the proximity sensor 5 can be arranged near the bottom dead center of the vertical displacement with a relatively large stroke of the vibrating bodies 1a and 3a, for example, as shown by the solid line in FIG. On the other hand, as indicated by a broken line in FIG. 2, one dead center of horizontal displacement that can detect the vibrating bodies 1a and 3a within a detectable distance within a relatively slow detection speed over a longer period of time. The proximity sensor 5 can also be arranged in the vicinity.

  Next, a schematic configuration of the low-frequency sound reduction device according to an embodiment of the present invention will be described with reference to the block diagram of FIG. The low-frequency sound reduction device of this embodiment has a controller 10 surrounded by a dotted line frame in FIG. This controller 10 is based on a frequency phase difference detector 11 to which an output signal from each proximity sensor 5a, 5b (proximity sensor 5 shown in FIG. 2) corresponding to each vibrating body 1a, 3a is input, and the detection result. The frequency control unit 13 for controlling the vibration frequency of the vibrating body 3a and the phase difference control unit 15 for controlling the phase of vibration are provided.

  The frequency phase difference detector 11 detects the vibration frequencies f1 and f2 of the vibrating bodies 1a and 3a and the vibration phase difference θ from the detection signals of the proximity sensors 5a and 5b. The frequency control unit 13 basically outputs a control amount for reducing the difference (f1-f2) between the vibration frequencies f1, f2 of the vibrating bodies 1a, 3a detected by the frequency phase difference detection unit 11. The phase difference control unit 15 is based on a difference u2 (= θ−target phase difference) between a vibration phase difference θ detected by the frequency phase difference detection unit 11 and a predetermined target phase difference. Thus, the control amount alpha for bringing the phase difference θ close to the target phase difference is calculated. The calculated control amount alpha is added in the adder 17 to the difference (f1-f2) between the vibration frequencies f1, f2 of the vibrators 1a, 3a input to the frequency control unit 13.

  The control amount output by the frequency control unit 13 is input to the inverter 20 as a speed command voltage for a motor in a drive source (not shown) that vibrates the vibrating body 3 a of the vibration sieve machine 3. The inverter 20 converts the input speed command voltage into a drive pulse for a motor (not shown) and outputs it to the vibration sieve machine 3 (a motor (not shown)).

  The displacements of the vibrating bodies 1a and 3a in the vibrating screens 1 and 3 of FIG. 1 are as shown in the graphs of FIGS. 4A and 4B, respectively, and each proximity sensor 5a and 5b has one of the vibration ranges. 5A and 5B, the waveforms of the output signals of the proximity sensors 5a and 5b are shown in the graphs of FIGS. 5A and 5B. As shown respectively.

  Therefore, the frequency phase difference detecting unit 11 measures the periods T1 and T2 between the rising edges of two consecutive pulses in the output signals of the proximity sensors 5a and 5b, respectively, and calculates the reciprocal of the measured periods T1 and T2 respectively. Detection is performed as vibration frequencies f1 and f2 of the vibrating bodies 1a and 3a. The frequency phase difference detector 11 measures the time difference Td from the rising edge of the pulse in the output signal of the proximity sensor 5a to the time point immediately after that when the pulse in the output signal of the proximity sensor 5b rises, and the measured time difference Td. The phase difference θ between the vibration frequencies f1 and f2 of the vibrating bodies 1a and 3a is detected from the period T2.

  Depending on the arrangement of the proximity sensors 5a and 5b, the waveforms of the output signals of the proximity sensors 5a and 5b are different from the waveforms shown in the graphs of FIGS. For example, when the range in which the vibrating bodies 1a and 3a can be detected by the sensitivity of the proximity sensors 5a and 5b is a partial range between both dead points of the vibrating range, the vibrating body 1a shown in FIG. , 3a, the waveforms of the output signals of the proximity sensors 5a, 5b are as shown in FIG. 6 (b). That is, the output signal changes from a low level to a high level during a part of the period when the vibrating bodies 1a and 3a approach one dead center of the vibration range and a part of the period when the vibrators 1a and 3a move away from one dead center. Change. In this case, for example, the frequency phase difference detection unit 11 detects the vibration frequency by measuring the pulse rising period corresponding to a part of the period when the vibrating bodies 1a and 3a approach one dead center of the vibration range. Will do.

  Further, when the range in which each vibrator 1a, 3a can be detected by the sensitivity of each proximity sensor 5a, 5b is a range from an intermediate point between both dead points of the vibration range to one dead point, FIG. 7), the waveforms of the output signals of the proximity sensors 5a and 5b are as shown in FIG. 7B. In other words, the output signals of the vibrating bodies 1a and 3a change from the low level to the high level in the range from the middle point between both dead points in the vibration range to one dead point. In this case, for example, the frequency phase difference detection unit 11 measures the time difference between the rising edges of two consecutive pulses as a period, and detects the vibration frequency.

  Next, a procedure for controlling the vibration frequency f2 and the vibration phase of the vibrating body 3a of the vibration sieve machine 3 by the controller 10 of FIG. 3 will be described with reference to the flowchart of FIG.

  First, the frequency phase difference detection unit 11 acquires output signals (output values) from the proximity sensors 5a and 5b and accumulates them in a built-in memory (not shown) (step S1). Next, using the accumulated output signals (output values) from the proximity sensors 5a and 5b, the vibration periods T1 and T2 of the vibration bodies 1a and 3a in the vibration sieves 1 and 3 corresponding to the proximity sensors 5a and 5b. And its time difference Td are calculated (step S3).

  Subsequently, the vibration frequencies f1, f2 of the vibrating bodies 1a, 3a and the phase difference θ are calculated from the calculated cycles T1, T2 and the time difference Td (steps S5, 7, 9). The vibration frequencies f1 and f2 can be calculated by obtaining the reciprocals of the periods T1 and T2. Further, the phase difference θ can be calculated by multiplying the time difference Td by (360 ° / T2).

  Next, the calculated difference (f2−f1) between the vibration frequencies f1 and f2 of the vibrators 1a and 3a is equal to or greater than a frequency difference threshold value ft (corresponding to a predetermined value in the claims) (f2−f1 ≦ −). It is confirmed whether or not ft or f2-f1 ≧ ft) (step S11). When the difference (f2−f1) is not equal to or greater than the threshold value ft (NO in step S11), the control amount alpha output from the phase difference control unit 15 to the adder 17 is set to zero (α = 0) (step S13). . When the difference (f2−f1) is equal to or greater than the threshold value ft (YES in step S11), the difference u2 between the vibration phase difference θ of the vibrating bodies 1a and 3a and the target phase difference (= θ−target phase difference). Is less than the reciprocal -ut (u2 <-ut) of the phase difference threshold value ut (corresponding to a predetermined amount in the claims) (step S15).

  When the difference u2 is less than the reciprocal of the threshold value ut (YES in step S15), the control amount alpha output from the phase difference control unit 15 to the adder 17 is the reference amount x (where x> 0). (Step S17). This reference amount x is a variable indicating the degree of approaching the phase difference θ to the target phase difference.

  On the other hand, when the difference u2 is not less than the reciprocal -ut of the threshold value ut (NO in step S15), the difference u2 between the vibration phase difference θ of the vibrating bodies 1a and 3a and the target phase difference (= θ−target position). It is confirmed whether or not (phase difference) is larger than the phase difference threshold value ut (u2> ut) (step S19).

  When the difference u2 is larger than the threshold value ut (YES in step S19), the control amount alpha output from the phase difference control unit 15 to the adder 17 is set to the reciprocal -x of the reference amount x (step S21). On the other hand, if the difference u2 is not greater than the threshold value ut (NO in step S19), the process proceeds to step S13.

Note that the above-described target phase difference is determined by the relative position of each of the vibrating screeners 1 and 3 with respect to the reduction target point A shown in FIG. That is, in the case shown in FIG. 1, the vibration sieving machines 1 and 3 are not equidistant from the reduction target point A. Therefore, if the low frequency sound generated by the vibrating bodies 1a and 3a of the vibrating screens 1 and 3 is simply set to the same frequency opposite phase, the low frequency sound cannot be reduced or canceled by the interference between the two. Therefore, with the same vibration frequency (= low frequency sound frequency) of the vibrating bodies 1a and 3a, the target phase difference is set according to the distances 1 and 2 from the reduction target point A to the vibrating bodies 1a and 3a. Will be determined. Specifically, as shown in FIG.
Target phase difference = 180 + 360 × {(distance 1−distance 2) / vibration wavelength of the vibrating body 3a (period T2 × sound speed)}
The target phase difference can be determined by the following equation.

  If the phase difference control unit 15 determines the control amount alpha to be output to the adder 17 in step S13, step S17, and step S21, the frequency control unit 13 sets the vibration frequencies f1 and f2 of the vibrating bodies 1a and 3a. The fs obtained by adding the control amount alpha to the difference (f2-f1) is defined as a variable for defining the deviation (fs-f1) of the proportional element Kp and the integral element Ki in the PID control (step S23).

  The frequency control unit 13 sets the motor speed command value fm to fm = fr + Kp (fs−f1) + ∫Ki (fs−f1), where fr is a variable corresponding to the difference between the previous control and the current control. (Step S25), converted into an analog motor speed command voltage and output to the inverter 20 (step S27). And a series of procedures are complete | finished.

  The above-described values such as the frequency difference threshold value ft, the phase difference threshold value ut, and the reference amount x of the control amount alpha are adjustment parameters that differ depending on the specifications of the vibration sieves 1 and 3. In this embodiment, the frequency phase difference detection unit 11 corresponds to the detection unit in the claims, and the frequency control unit 13 and the phase difference control unit 15 correspond to the control unit in the claims.

  By executing the above procedure, the low frequency sound generated by the vibrating body 1a of the vibrating screen 1 at the reduction target point A is generated by the vibrating body 3a of the vibrating screen 3 whose frequency and phase are controlled by the controller 10. The level of the low frequency sound at the reduction target point A is reduced by being reduced and offset by the interference with the low frequency sound.

  According to the low-frequency sound reduction device of the present embodiment having the controller 10 configured as described above, the non-optical proximity in which the vibrating bodies 1a and 3a of the vibrating screens 1 and 3 are arranged in the vicinity of the vibration range. Detected by sensors 5a and 5b. For this reason, when the vibration sieving machines 1 and 3 are used for sieving articles that cannot avoid the generation of dust such as coal and wood chips, the detection light path is blocked or detected by the dust when detecting the vibrating bodies 1a and 3a. It is not affected by light being refracted.

  Therefore, for the vibration sieving machines 1 and 3 that perform sieving in which generation of dust is unavoidable, the vibration frequency and phase of the vibrating bodies 1a and 3a are accurately grasped and their control amounts are accurately determined, and the reduction target point The low frequency sound in A can be efficiently reduced.

  Whether the control amount alpha relating to the phase difference is set to zero or any other value is determined by a procedure different from the procedure of steps S11 to S23 in the flowchart of FIG. 8 performed in this embodiment. Also good. That is, whether priority is given to control for reducing the difference between the vibration frequencies f1 and f2 of the vibrating bodies 1a and 3a in the respective vibration sieving machines 1 and 3, or priority is given to control for bringing the phase difference θ closer to the target phase difference. The procedure may be determined by a procedure different from the procedure of steps S11 to S23 in the flowchart.

  Incidentally, as in the present embodiment, when the difference between the vibration frequencies f1 and f2 is larger than the frequency difference threshold value ft, priority is given to the control for reducing the difference between the phase difference θ and the target phase difference. The difference between the phase difference θ and the target phase difference can be efficiently reduced rather than giving priority to the control for reducing the difference.

  Further, as in the present embodiment, when the difference between the vibration frequencies f1 and f2 is smaller than the frequency difference threshold ft and the absolute value of the phase difference θ is larger than the phase difference threshold ut, If priority is given to control for reducing the difference between the phase difference θ and the target phase difference, and the absolute value of the phase difference θ is smaller than the threshold value ut of the phase difference, the difference between the vibration frequencies f1 and f2 is eliminated. Also by performing the control, the difference between the phase difference θ and the target phase difference can be efficiently reduced.

  Further, in the present embodiment, the proximity sensor 5 (5a, 5b) detects the vibrating bodies 1a, 3a. For example, the proximity sensor 5 (5a, 5b) is synchronized with the vibrating bodies 1a, 3a inside the vibration sources 1b, 3b in FIG. The elements that operate in this manner may be detected by the proximity sensors 5a and 5b.

  As shown in the explanatory view of FIG. 9, the vibration sources 1b and 3b of FIG. 2 have a motor 4 and two fan-shaped eccentric weights 4a and 4b attached to the output shaft of the motor 4 so as to be adjustable in angle. ing.

  As shown in the perspective view of FIG. 10, each of the eccentric weights 4a and 4b has a slit 4c for fixing to the output shaft of the motor 4 by tightening a bolt 4d. Therefore, the positions of the eccentric weights 4a and 4b in the rotation direction of the output shaft of the motor 4 can be changed by tightening the bolts 4d.

  As described above, by appropriately adjusting the mounting positions of the eccentric weights 4a and 4b with respect to the output shaft of the motor 4 in the rotation direction of the output shaft of the motor 4, the centrifugal force generated by both the eccentric weights 4a and 4b is adjusted. The vibration frequency by the vibration sources 1b and 3b of the vibrating bodies 1a and 3a can be adjusted.

  Therefore, in place of the proximity sensors 5a and 5b arranged in the vicinity of the vibration range of the vibrating bodies 1a and 3a as shown in FIG. 2, the housing of the vibration sources 1b and 3b is externally provided outside the rotation locus of the eccentric weight 4b. The proximity sensors 5a and 5b may be arranged in a sealed state.

  In this case, the frequency phase difference detector 11 (see FIG. 3) determines the vibration frequencies f1, f2 of the vibrating bodies 1a, 3a from the pulse interval in which the output signals of the proximity sensors 5a, 5b change as the eccentric weight 4b passes. The phase difference θ of vibration can be detected. The proximity sensors 5a and 5b in FIG. 9 are sealed from the outside by the housings of the vibration sources 1b and 3b. Therefore, the proximity sensors 5a and 5b need not be limited to the non-optical type in consideration of the influence of dust and the like. Can be used. Even if comprised in this way, the effect similar to embodiment mentioned above can be acquired.

  In the above embodiment, the case where the present invention is implemented for two vibrating sieve machines 1 and 3 has been described as an example. However, the present invention further includes the third and subsequent vibratory sieves, and the vibration frequency of the vibrator in another vibratory sieve is based on the vibration frequency and phase of the vibrator in one of the vibratory sieves. It is also applicable when controlling the phase.

DESCRIPTION OF SYMBOLS 1 Vibrating screen machine 1a Vibrating body 1b Vibrating source 3 Vibrating sieve machine 3a Vibrating body 3b Vibrating source 4a Eccentric weight 4b Eccentric weight 5 Proximity sensor 5a Proximity sensor 5b Proximity sensor 10 Controller 11 Frequency phase difference detection part 13 Frequency control part 15 Phase difference Control unit 17 Adder 20 Inverter A Reduction target point

Claims (2)

A device that reduces the low-frequency sound generated by the vibration of each vibrating body by a plurality of vibrating screens by mutual interference,
A non-optical proximity sensor for detecting the corresponding vibrating body, which is disposed in the vicinity of the vibrating range of the vibrating body of each vibrating screen machine and approaches within a detectable distance, or together with a vibration source of the vibrating body A proximity sensor that is arranged in a sealed state and detects a vibrator of the vibration source that is approached within a detectable distance; and
From the waveform of the detection signal of the vibrating body by each proximity sensor, detection means for detecting the vibration frequency and phase of the vibrating body for each of the vibrating screeners,
With respect to the vibration of the vibrating body of the one vibrating screen detected by the detecting means, the vibration of the vibrating body of the other vibrating screen detected by the detecting means has the same frequency and the low frequency. Based on the vibration frequency and phase of the vibrating body for each of the vibration sieves detected by the detection means so that a predetermined phase difference determined by the relative position difference with respect to the target point of frequency sound reduction is obtained, the other vibrations Control means for controlling the vibration of the vibrating body in the sieve machine;
A low-frequency sound reduction device using a vibration sieve. The control means includes
When the vibration frequency of the vibration body of the other vibration screener is larger than a predetermined value with respect to the vibration frequency of the vibration body of the one vibration screener, the deviation of the vibration frequency is made smaller than the predetermined value. The vibration frequency control of the vibrating body is performed for the other vibration sieving machine,
The deviation of the vibration frequency of the vibration body of the other vibration screener with respect to the vibration frequency of the vibration body of the one vibration screener is smaller than the predetermined value, and the vibration of the vibration body of the one vibration screener When the phase difference of the vibration of the vibrating body of the other vibration sieving machine is more than a predetermined amount with respect to the predetermined phase difference, the phase difference is less than the predetermined amount. Perform the phase control of the vibration of the vibrating body for the other vibration sieving machine,
The deviation of the vibration frequency of the vibration body of the other vibration screener with respect to the vibration frequency of the vibration body of the one vibration screener is smaller than the predetermined value, and the vibration of the vibration body of the one vibration screener When the deviation between the vibration phase difference of the vibrating body of the other vibrating screener and the predetermined phase difference is smaller than the predetermined amount, the vibration frequency of the vibrating body of the one vibrating screener is set to the other frequency. The vibration frequency control for bringing the vibration frequency of the vibration body of the vibration sieve machine close to the other vibration sieve machine is performed.
The low-frequency sound reduction device by the vibration sieve according to claim 1.

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