JPH0796103A - Ultrasonic defoaming device - Google Patents

Abstract

PURPOSE:To provide an ultrasonic defoaming device equipped with a foam detector by which foam is surely detected in a contaminated atmosphere of a limited space irrespective of kinds of chemicals by making an ultrasonic vibrator for transmitting ultrasonic waves for breaking foam on the surface of the liquid also serve as an ultrasonic receiver for receiving reflected waves from the surface of the liquid and the foam. CONSTITUTION:In an ultrasonic defoaming device equipped with an ultrasonic vibrator 48 for transmitting ultrasonic waves for breaking foam on the surface of the liquid, the ultrasonic vibrator 48 is used also as an ultrasonic receiver for receiving reflected waves from the surface of the liquid or the foam. When the existence of foam swelling on the surface of the liquid is detected by the reflected waves received by the ultrasonic vibrator 18, intense ultrasonic waves are transmitted from the ultrasonic vibrator 48 to break the foam. Further, after the defoaming by the ultrasonic vibrator 48 is performed in a prescribed time, the reflected waves are received by the ultrasonic vibrator 48. As a result, the ultrasonic defoaming device equipped with a foam detector by which foam is surely detected in a contaminated atmosphere of a limited space irrespective of kinds of chemicals is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic bubble breaking device, and more particularly, it is suitable for improving the basic unit of a liquid and preventing the environmental pollution of the liquid when a gas containing a gas such as paint or a foaming liquid is circulated and used. The present invention relates to an ultrasonic bubble breaking device.

[0002]

2. Description of the Related Art Conventionally, when circulating a foamable liquid,
A general circulation line as shown in FIG. 1 was used.

In this circulation line, the liquid is stored in the reserve tank 10, the pressure is raised by the liquid feed pump 14 from the liquid feed nozzle 12 provided in the lower part of the reserve tank 10, and the liquid passes through the liquid feed line 16. And is pumped to the liquid use place 18. The remaining liquid used at the liquid use place 18 is pressurized again by the return pump 20 and returned to the reserve tank 10 through the return pipe line 22.

Such foaming in the circulation pipe mainly occurs between the liquid use place 18 and the return pipe 22, and the liquid containing the foam is returned to the reserve tank 10. Therefore, if the circulation is continued, the reserve tank 10 will be discharged. The space is filled with bubbles and overflows from the opening 10A. The bubbles of the effervescent liquid were hard to disappear even when they went out of the tank, and the surroundings were contaminated, and the leakage continued, resulting in a large loss of the liquid.

Conventionally, as a countermeasure against this, as shown in FIG. 2, a nozzle 1 for discharging bubbles is attached to a lid 11 of a reserve tank 10.
1A was provided, the foam was guided to the adjacent defoaming tank 24, and the defoaming liquid was sprayed from the nozzle 24A to break the foam (break the foam). As the defoaming liquid, water or a circulating liquid was used, but if water is used, the liquid mixed with water cannot be reused, so the loss of the liquid is unavoidable, and even if the circulating liquid itself is used, it will Bubbles remained, and again it was difficult to reuse.

[0006] In addition, as a method and apparatus for spraying a liquid to destroy bubbles, Japanese Patent Laid-Open No. 123100/123100 discloses that the bubbles of the treatment liquid generated during the cleaning of the steel sheet are of the same type as this treatment liquid and By injecting a lower temperature processing liquid,
It has been proposed to effectively defoam to prevent the bubbles from flowing out and to collect them as a treatment liquid. Further, as the same type, Japanese Patent Laid-Open No. 153887/1993 discloses a method of cleaning oil stains and the like on a metal material, introducing an upper layer portion of a foamed alkaline cleaning solution to an overflow tank, and spraying the foamed portion in the overflow tank with a mist. A method has been proposed in which water is sprayed to defoam the foaming portion while maintaining the cleaning performance of the alkaline cleaning liquid in the storage tank.

As a device for mechanically destroying bubbles,
Japanese Examined Patent Publication No. 2-20001 with a motor provided with blades,
Installed on a float with legs arranged on the outer circumference of the plate blades with a space, and by using a floating defoaming device that rotates the plate blades in the space closest to the water surface, bubbles generated by moving on the water surface are generated. A defoaming device that defoams by colliding with a blade has been proposed.

Further, as a combination of a method of mechanically breaking bubbles and a method of spraying a liquid to break bubbles,
In JP-A-64-56897, the plating solution is sprayed on the bubbles on the upper surface of the plating solution, and the bubbles are stirred to surely eliminate the bubbles of the fine particle dispersion type electroplating solution, thus continuously using the plating bath for a long time. Methods have been proposed to enable.

In addition to this, a bubble separating device for separating bubbles from a liquid has been proposed in Japanese Patent Laid-Open No. 52-20703.

As described above, various measures have been proposed, but all of them have problems in terms of simplicity and certainty of effect, because the device is complicated and the effect is insufficient.

In recent years, the diversification of the types of circulating liquids has been extremely remarkable, and the proportion of foamable liquids such as resin has also increased, and the demand for a continuous bubble breaking device in the circulation line has increased. ing.

In view of such a situation, the applicant has proposed an ultrasonic foam breaking device as shown in FIG. 3 in Japanese Patent Application No. 4-133520 (not yet published).

In this ultrasonic bubble breaking device, the chemical liquid in the reserve tank 10 is moved by the liquid feed pump 14 to a liquid use place 18
Used to be transported to. The used chemical liquid is returned to the defoaming tank 30 by the return pump 20. At this time, bubbles are mainly generated between the liquid use place 18 and the return pipe line 22. Therefore, bubbles are generated on the liquid surface of the drug solution collected in the defoaming tank 30, and the drug solution returns to the reserve tank 10 via the siphon pipe 34 by its own weight and is circulated and used.

A bubble detector 42 is provided on the side surface of the defoaming tank 30 for generating a bubble detection signal by detecting that the bubble has risen to a certain height from the liquid surface.

Further, an ultrasonic transducer 48 composed of an ultrasonic transducer 48 and a horn 50 is provided above the defoaming tank 30.
Is mounted so as to face the liquid surface. The horn 50
Is manufactured in a shape that resonates at the frequency of the ultrasonic waves supplied from the ultrasonic transmitter 44.

On the other hand, in the vicinity of the liquid surface in the defoaming tank 30, a reflection screen 52 having a through hole through which bubbles can pass.
Is provided so as to cover the entire liquid surface. The tip surface of the reflection screen 52 and the horn 50 (the lower surface in the figure)
The distance between the reflection screen 52 and the horn 5 is set to an odd multiple of a quarter wavelength of the ultrasonic transmission frequency.
A standing wave is set to stand between zero.

The electric energy of the ultrasonic waves supplied from the ultrasonic transmitter 44 is applied to the ultrasonic vibrator 48, and the ultrasonic vibrator 48 vibrates at a corresponding frequency. Horn 5
Since 0 is formed in a shape that resonates at this frequency, ultrasonic vibrations are amplified and the pressure amplitude of ultrasonic waves is applied to the liquid surface from the tip surface of the horn 50. Defoaming tank 30
The bubbles inside increase with time and increase in height, and the bubble detector 42 detects the bubbles and sends a transmission command to the ultrasonic transmitter 44. Then, the ultrasonic wave transmitter 44 intermittently emits ultrasonic waves, and in synchronization with this, ultrasonic wave pressure amplitude is emitted from the tip surface of the horn 50.

The pressure amplitude of the applied ultrasonic wave overlaps with the pressure amplitude reflected by the reflection screen 52 to generate a standing wave. Then, if the pressure located at the antinode of the standing wave is equal to or higher than the strength of the foam film, the foam located there is destroyed and returns to the original liquid medicine. If the bubbles are broken and the bubbles are reduced in this way, the bubble detector 4
The output of 2 is turned off, and the transmission of ultrasonic waves by the ultrasonic transmitter 44 is stopped. After that, this operation is repeated to continuously break the bubbles.

As the bubble detector 42 used in such an ultrasonic bubble breaking device, a photoelectric tube type, a capacitance type, an ultrasonic type and the like can be considered. However, since the photoelectric tube type uses a light emitter / receiver, it has a lens surface. Has a problem that it is difficult to detect stably for a long time. Further, the capacitance type has a problem that not only is the electrode corroded by the chemical liquid, but also the dielectric constant changes when the type of the chemical liquid changes, so the detection level changes and malfunctions are likely to occur. In addition, the ultrasonic type is non-contact and has higher reliability than the phototube type and the capacitance type, but not only does it have a space for installation, but it is also expensive. It has a problem that it may malfunction due to the influence of sound waves.

The present invention has been made to solve such a problem, and provides a bubble detector capable of reliably detecting bubbles in a contaminated atmosphere in a limited space without being influenced by the type of the chemical solution. An object of the present invention is to provide an ultrasonic defoaming device equipped with the device.

[0021]

DISCLOSURE OF THE INVENTION The present invention provides an ultrasonic defoaming apparatus equipped with an ultrasonic vibrator for transmitting ultrasonic waves for breaking bubbles on a liquid surface, The object is achieved by also serving as an ultrasonic receiver for receiving reflected waves from the liquid surface and bubbles.

When the presence of bubbles rising on the liquid surface is detected by the reflected wave received by the ultrasonic transducer, strong ultrasonic waves are transmitted from the ultrasonic transducer to generate bubbles. Is designed to destroy.

In addition, after the ultrasonic oscillator breaks bubbles for a predetermined time, the ultrasonic oscillator receives a reflected wave.

[0024]

In the present invention, the ultrasonic transducer for transmitting the ultrasonic wave that destroys the bubbles on the liquid surface is also used as the ultrasonic receiver for receiving the reflected waves from the liquid surface and the bubbles, and it is weak. The pulse is applied to the bubble, the reflected pulse is received by the ultrasonic receiver, and the time between them is measured to measure, for example, the distance between the horn and the bubble. That is, the ultrasonic transducer is also used as the range finder.

Therefore, it is not necessary to separately provide a space for installing a bubble detector, and since no lens or electrode is used, it is resistant to contamination and is also an ultrasonic rangefinder that is not affected by the type of chemical solution. It is possible to configure a foam breaking device.

[0026]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In this embodiment, as shown in FIG. 4, a changeover switch 60 is provided between the ultrasonic oscillator 48 and the ultrasonic transmitter 44 which are attached to the upper part of the defoaming tank 30. The ultrasonic distance meter circuit 62 can be connected to the ultrasonic vibrator 48.

The ultrasonic range finder circuit 62 generates a weak pulse for distance measurement and transmits it to the ultrasonic oscillator 48, and a reflected pulse received by the ultrasonic oscillator 48. It is configured to include a pulse receiver 66 for receiving, and a distance measuring unit 68 for measuring the time until a pulse is output and received again by the output of the pulse receiver 66.

Since the other points are the same as those of the comparative example shown in FIG. 3, description thereof will be omitted.

The operation of the embodiment will be described below.

The changeover switch 60 is usually on the side of the rangefinder. In this state, the pulse oscillator 64 outputs a pulse signal having the same half cycle as the oscillation frequency of the ultrasonic oscillator 44 to the ultrasonic transducer 48. This pulse signal is
It is converted into an ultrasonic pulse and is applied to the bubble via the horn 50.

Some of the reflected pulses from the bubbles reach the horn 50. Since the horn 50 is designed and manufactured so as to resonate with the transmission frequency of the ultrasonic transmitter 44, the reflected signal is amplified by the horn 50, the signal-to-noise ratio is improved, and the reflected signal is guided to the ultrasonic transducer 48. , And finally received by the pulse receiver 66.

The distance measuring unit 68 measures the time t from the output of the pulse from the pulse transmitter 64 to the reception by the pulse receiver 66 again, and calculates the distance L to the bubble by the following equation. Where v is the speed of sound.

L = v / 2t (1)

In practice, the irradiation pulse is not limited to bubbles.
Since it reflects on the liquid surface, the reflection screen, and the bottom of the defoaming tank, and the waveform as shown in FIG. 5 can be observed at the pulse receiver 66, the threshold level of the detection signal and the monitoring section are appropriately selected to The ultrasonic range finder circuit 62 is configured to detect only the reflected pulse from. The waveform in FIG. 5 shows the state in which the liquid level is higher than that of the reflection screen in the apparatus of FIG.

With the above construction, the height of the bubble is constantly detected, and when the height of the bubble reaches a certain level, the changeover switch 60 is switched to the bubble breaking side and the ultrasonic wave transmitter 44 is intermittently operated for a certain period of time. Drive to break the bubbles.

Then, after intermittent irradiation for a while, the mode is switched to the rangefinder again and the distance to the bubble is measured. If the distance is above a certain level, the number of bubbles has decreased and the ultrasonic irradiation for breaking bubbles is stopped. If bubbles still exist, switch to the bubble breaking side again and break the bubbles for a certain period of time.

In this way, by properly switching between the rangefinder side and the bubble breaking side, efficient bubble detection and bubble breaking can be performed.

In particular, in the comparative example, when the standing wave between the horn and the liquid surface was used to break the bubbles, it was necessary to install two detectors, a bubble detector and a liquid level detector. By preparing a plurality of monitoring sections and threshold levels in FIG. 5, one detector can detect both the distance to the bubble and the level to the liquid surface.

[0040]

As described above, according to the present invention,
There is no need to provide a separate space for installing a bubble detector, and since no lens or electrode is used, it is resistant to contamination and is not affected by the type of chemical solution. It has an excellent effect that the device can be configured.

[Brief description of drawings]

FIG. 1 is a pipeline diagram showing the configuration of a general circulation pipeline.

FIG. 2 is a sectional view of an essential part showing the configuration of an example of a conventional foam breaking device.

FIG. 3 is a pipeline diagram showing a configuration of a comparative example proposed by the applicant in Japanese Patent Application No. 4-133520.

FIG. 4 is a conduit diagram showing a main part configuration of an embodiment of an ultrasonic bubble breaking device according to the present invention.

FIG. 5 is a diagram showing an example of an ultrasonic wave reception waveform in the embodiment.

[Explanation of symbols]

 30 ... Defoaming tank 42 ... Bubble detector 44 ... Ultrasonic transmitter 48 ... Ultrasonic vibrator 60 ... Changeover switch 62 ... Ultrasonic distance meter circuit 64 ... Pulse transmitter 66 ... Pulse receiver 68 ... Distance measuring unit

Claims (3)

[Claims] 1. An ultrasonic bubble breaking device comprising an ultrasonic vibrator for transmitting ultrasonic waves for breaking bubbles on a liquid surface, the ultrasonic vibrator comprising: An ultrasonic defoaming device, which is also used as an ultrasonic receiver for receiving. 2. The method according to claim 1, wherein when the presence of bubbles rising on the liquid surface is detected by the reflected wave received by the ultrasonic transducer, strong ultrasonic waves are emitted from the ultrasonic transducer. An ultrasonic bubble breaking device characterized by transmitting and breaking bubbles. 3. The ultrasonic bubble breaking device according to claim 1, wherein after the bubble is broken by the ultrasonic vibrator for a predetermined time, the reflected wave is received by the ultrasonic vibrator.