JPH0431722B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ultrasonic defoaming method and device. Generally, it is necessary for certain liquids to be defoamed. For example, if a photosensitive emulsion for photosensitive film is applied to the film material while containing air bubbles, it will not be possible to form a uniform photosensitive film on the photosensitive film, so it must be defoamed before being applied to the film material. It is necessary. As an example of a device for carrying out such defoaming treatment, the device disclosed in Japanese Patent Publication No. 57-6365 is known. This device includes an ultrasonic liquid tank 100 and an ultrasonic liquid tank 100 as shown in FIG.
A defoaming tank 103 formed by, for example, communicating a first cylindrical body 101 and a second cylindrical body 102 with each other at the upper part, and a bottom part of the first cylindrical body 101 and the second cylindrical body 102. It has a defoaming liquid supply pipe 104 and a defoaming liquid discharge pipe 105 each inserted from above so as to reach the vicinity, and an ultrasonic oscillator 106 disposed below the defoaming tank 103. The defoamed liquid from the defoamed liquid supply pipe 104 rises to the upper part of the first cylindrical body 101, then reaches the upper part of the second cylindrical body 102, and then descends from there to be discharged. The liquid to be defoamed is irradiated with ultrasonic waves from an ultrasonic oscillator 106 until it is discharged through the pipe 105, and the bubbles are floated by the radiation pressure of the ultrasonic waves, thereby defoaming them. In the figure, 107 is a float, and 108 is an air vent valve. In order to increase the throughput per unit time, that is, the degassing ability in ultrasonic defoaming treatment,
It is conceivable to increase the energy of the ultrasonic waves, but in the above-mentioned apparatus, the degassing liquid in the two cylindrical bodies 101 and 102 is irradiated with ultrasonic waves by a common ultrasonic oscillator 106. Therefore, when the energy of the ultrasonic waves is increased, new bubbles are generated due to the cavitation effect, and the bubbles generated in the second cylindrical body 102 are sucked and discharged into the defoaming liquid discharge pipe 105, and as a result, the defoaming occurs. Bubbles will be included in the defoamed liquid that has passed through the process, making it impossible to perform sufficient defoaming. Furthermore, in the above-mentioned apparatus, when used for a long time, sedimentary particles such as silver halide in the photosensitive emulsion tend to accumulate on the bottom surfaces of the cylinders 101 and 102, and when cleaning the defoaming tank 103 to remove the deposits, , remove the defoaming liquid supply pipe 104 and the defoaming liquid discharge pipe 105 from the defoaming tank 103, and then remove the defoaming tank 103.
The cleaning work is troublesome because it has to be removed from the ultrasonic liquid bath 100 and cleaned, and the cleaning work becomes extremely troublesome especially in a large-sized device. The present invention has been made based on these circumstances, and an object of the present invention is to provide an ultrasonic defoaming method that can significantly improve the defoaming ability. Another object of the present invention is to ensure defoaming,
An object of the present invention is to provide an ultrasonic defoaming device that allows cleaning work to be easily performed. The feature of the ultrasonic defoaming method of the present invention is that in the ultrasonic defoaming method in which a liquid to be degassed is defoamed by irradiating ultrasonic waves, the degassed liquid is A first step of irradiating the defoamed liquid with ultrasonic waves having energy that causes a cavitation effect while raising the foamed liquid; and a second step of irradiating the degassing liquid from below with an ultrasonic wave of energy that does not cause a cavitation effect while descending along a second flow path that extends downward continuously. The ultrasonic defoaming device of the present invention includes an ultrasonic liquid tank, and two conical cylindrical bodies immersed in the ultrasonic liquid tank, each of which has a lower part expanding upward, and which are connected to each other at the upper part. a defoaming tank that communicates with the defoaming tank; a defoaming liquid supply pipe connected to the lower end of one of the two cylindrical bodies;
The present invention includes a defoaming liquid discharge pipe connected to the lower end of the other of the two cylindrical bodies, and a pair of ultrasonic oscillators provided below the defoaming tank. The present invention will be explained below with reference to the drawings. In the present invention, as shown in FIG. 2, the liquid to be defoamed, such as a silver halide emulsion (gelatin liquid) for photosensitive film, is passed along the first flow path _P1 extending upward.
a first step of irradiating the liquid to be degassed with ultrasonic waves of energy that causes a cavitation effect, for example, from below, using the first ultrasonic oscillator 2A while raising the While lowering the degassing liquid that has undergone the first step along the second flow path P2 that extends downward continuously, the first
A second step of irradiating the liquid to be defoamed with ultrasonic waves of energy that does not cause cavitation effects by a second ultrasonic oscillator 2B that is separate from the ultrasonic oscillator 2A of Perform defoaming processing on the liquid to be defoamed. In the above, the first ultrasonic oscillator 2A and the second
The ultrasonic frequency of each ultrasonic oscillator 2B is 10~
It is preferable to set it to 100KHz. Regarding the magnitude of the output of the ultrasonic oscillator, the output of the first ultrasonic oscillator 2A is set to a level such that cavitation effect occurs, for example, normal hydrostatic pressure (1 Kg/cm ² ).
0.35W/cm ² or more, and the second ultrasonic oscillator 2
^The output of
0.35W/ ^cm2 or less. According to the above method, in the first step,
The bubbles in the liquid to be defoamed are pushed up by the radiation pressure of the ultrasonic waves from the first ultrasonic oscillator 2A, and the bubbles aggregate due to the cavitation effect of the ultrasonic waves, becoming large bubbles that float to the surface. Most of the bubbles are separated from the foam liquid. In the second step, the air bubbles remaining in the descending flow of the liquid to be defoamed are pushed up and floated by the radiation pressure of the ultrasonic waves from the second ultrasonic oscillator 2B, and are separated from the liquid to be defoamed. Moreover, no new bubbles are generated due to the cavitation effect. In this way, in the ultrasonic defoaming method of the present invention, the first
Since the energy of the ultrasonic waves irradiated in the flow path P1 is large enough to cause a cavitation effect, the aggregation of air bubbles in the liquid to be defoamed is greatly promoted, and as a result, the flow velocity of the liquid to be defoamed can be increased. In addition, since the energy of the ultrasonic waves irradiated in the second flow path P2 is small enough to cause no cavitation effect, new bubbles are not generated due to the cavitation effect, and the bubbles are absorbed into the defoamed liquid. It is not discharged together with the Therefore, sufficient defoaming can be performed while obtaining a high defoaming ability. Although the method of the present invention is suitable for defoaming a silver halide emulsion (gelatin liquid) for photosensitive film, the liquid to be defoamed is not limited thereto. In the above, the flow path for the defoamed liquid in the second flow path P2 is made large enough to allow the ultrasonic waves from the second ultrasonic oscillator 2B to push up the remaining air bubbles, and the degassed liquid is For example, the viscosity of
When it is 50 cp, it is preferable to set it as 0.1-0.5 cm/sec. Furthermore, in the present invention, when irradiating ultrasonic waves to the liquid to be defoamed rising in the first flow path _P1 , it is most preferable to irradiate the ultrasonic waves from below the liquid to be defoamed. Ultrasonic waves may be irradiated from the side of the foam liquid. In the method of the present invention, the first ultrasonic oscillator 2
Even if the output of A is not very large, for example, 0.35W/
cm ² to 0.7 W/cm ² , if most of the bubbles in the defoamed liquid can be removed in the first flow path P1, the defoamed liquid in the second flow path P2 The energy of the ultrasonic waves to be irradiated to the channel P2 may be small, and in order to irradiate the ultrasonic waves with such a small energy, it is necessary to operate the ultrasonic oscillator 2B located below the second flow path P2, and to Flow path P1
The ultrasonic wave from the lower ultrasonic oscillator 2A may be propagated into the second flow path P2 and the ultrasonic wave whose energy has been weakened may be used. Next, to explain the device of the present invention, 1 in FIGS. 3 and 4 maintains the temperature of the liquid to be defoamed at a constant temperature, and evenly disperses and propagates ultrasonic waves in the liquid to be defoamed. This is an ultrasonic liquid tank 1 for cooling a diaphragm of an ultrasonic oscillator, and a hot water supply pipe 11 and a hot water discharge pipe 12 are connected to the upper and lower parts of the ultrasonic liquid tank 1, respectively. In this ultrasonic liquid tank 1,
each conical first whose lower portion expands upward;
and a second cylindrical body 32 connected to each other at the upper part thereof.
A flange-shaped protruding plate 33 formed on the outer periphery of the defoaming tank 3 is attached to a protruding edge 13 that protrudes inward from the upper end of the ultrasonic liquid tank 1.
The defoaming tank 3 is fixed to the ultrasonic liquid tank 1 by overlapping and fixing, and the ultrasonic liquid tank 1 is sealed. The defoaming liquid supply pipe 4 and the defoaming liquid discharge pipe 5 are connected to each other, and the inside of the first cylindrical body 31 is placed at a position directly below the first cylindrical body 31 on the bottom surface of the ultrasonic liquid tank 1. A first ultrasonic oscillator 2A for irradiating ultrasonic waves to the liquid to be defoamed is provided, and a second cylinder is installed at a position directly below the second cylinder 32 on the bottom of the ultrasonic liquid tank 1. A second ultrasonic oscillator 2B is provided for irradiating ultrasonic waves to the degassing liquid in the shaped body 32. As the ultrasonic oscillator here, for example, a waterproof piezoelectric type having a titanate-lead zirconate vibrator can be used. and the first cylindrical body 3
1 and the upper end of the second cylindrical body 32, respectively.
By providing valves 11 and 312, the defoaming tank 3 is sealed, and a valve 61 is provided on the lid 312 of the second cylindrical body 32.
An air vent pipe 6 having a diameter is connected and provided. Further, the first cylindrical body 31 is provided with a float 7 for determining the level of the liquid to be defoamed, and a level indicating rod 71 extending upward from the float 7 and having a level indicating portion is attached to the lid. 311, thereby forming an ultrasonic defoaming device. In the above-mentioned device, first, hot water is filled into the ultrasonic liquid tank 1, and hot water is constantly supplied from the hot water supply pipe 11, and hot water is discharged from the hot water discharge pipe 12 to maintain the liquid level at a predetermined level L1. Make it.
Then, the valve 61 is opened and the defoamed liquid is supplied from the defoamed liquid supply pipe 4 into the defoamed tank 3 . The defoamed liquid rises inside the first cylindrical body 31 and then descends inside the second cylindrical body 32, but the defoamed liquid discharge pipe 5 is bent upward outside the ultrasonic liquid tank 1. By extending it to the top of the defoaming tank 3, the level of the defoamed liquid in the second cylindrical body 32 rose, and the level of the defoamed liquid reached a predetermined level L2. By the way, valve 61 is closed. Furthermore, when the liquid to be defoamed is supplied into the defoaming tank 3, the liquid pressure due to the difference between the liquid level in the defoaming tank 3 and the liquid level of the defoaming liquid discharge pipe 5 and the internal pressure of the defoaming tank 3 are The liquid level in the defoaming tank 3 is maintained when the values match, and in this state, the flow rate of the defoaming liquid flowing in from the defoaming liquid supply pipe 4 and the flow rate of the defoaming liquid flowing out from the defoaming liquid discharge pipe 5 are maintained. The flow rate of the liquid to be defoamed matches the flow rate of the liquid to be defoamed, and the flow of the liquid to be defoamed in the defoaming tank 3 is in a steady state. By operating the first ultrasonic oscillator 2A and the second ultrasonic oscillator 2B, the liquid to be degassed from the liquid to be degassed supply pipe 4 flows into the upper part of the first cylindrical body 31. Defoaming is performed by ultrasonic waves while the liquid rises, reaches the upper part of the second cylindrical body 32, descends from there, and is discharged through the defoaming liquid discharge pipe 5. In this way, in the device of the present invention, the defoaming tank 3
A first cylindrical body 31 and a second cylindrical body 3 each having a conical shape whose lower portion expands upward.
2, and the degassing liquid supply pipe 4 and the degassing liquid discharge pipe 5 are connected to the lower ends of the first cylindrical body 31 and the second cylindrical body 32, respectively, so that the degassing liquid is The flow of the foamed liquid becomes a laminar flow, and in this state, the liquid to be defoamed rises in the defoaming tank 3 and then descends, so that the ultrasonic waves can be uniformly applied to the liquid to be defoamed. Therefore, defoaming can be performed reliably, and the first cylindrical body 31 and the second cylindrical body 32 can be
Since the inner wall surface at the lower part of the tank is sloped, it is difficult for sedimentary particles such as silver halide in the liquid to be degassed to accumulate, and even if they do, the amount of accumulated particles is small, and therefore the defoaming tank 3 must be removed. No, lid 311,3
The cleaning liquid is supplied from the upper end of the defoaming tank 3 from which the degassing tank 12 has been removed, and the cleaning liquid is supplied from the lower end of the first cylindrical body 31 and the second
By discharging from the lower end of the cylindrical body 32,
Accumulated sedimentary particles can be easily washed away, and therefore cleaning work can be easily performed, and even if the apparatus is large, the cleaning work is easy. In order to apply the above-mentioned defoaming method to the above-mentioned apparatus, the following procedure may be performed. That is, the output of the first ultrasonic oscillator 2A is adjusted to a level such that the cavitation effect occurs, for example, normal hydrostatic pressure (1
Kg/cm ² ) is set to 0.35 W/cm ² or more, and the output of the second ultrasonic oscillator 2B is set to a level such as normal hydrostatic pressure (1 Kg/cm 2 ) so that no cavitation effect occurs.
cm ² ) is 0.35W/cm ² or less. Note that when the liquid to be defoamed is pressurized, the limit value of the output of the ultrasonic oscillator that causes cavitation effect moves toward a larger value. By setting the outputs of the first ultrasonic oscillator 2A and the second ultrasonic oscillator 2B in this way, while the degassing liquid supplied to the first cylindrical body 31 rises, The radiation pressure of the ultrasonic waves from the first ultrasonic oscillator 2A pushes up the bubbles in the liquid to be defoamed, and the cavitation effect of the ultrasonic waves causes the bubbles to aggregate into large bubbles that float to the surface. Most of the bubbles are then separated from the liquid to be defoamed. and second cylindrical body 32
As the liquid to be defoamed descends inside, the air bubbles remaining in the descending flow are pushed up and floated by the radiation pressure of the ultrasonic waves from the second ultrasonic oscillator 2B, and are separated from the liquid to be defoamed. In the above, the flow rate of the liquid to be defoamed from the first cylindrical body 31 to the second cylindrical body 32 is
The size is such that most of the air bubbles floating in the second cylindrical body 32 do not flow into the second cylindrical body 32 . When degassing is performed as described above, the following effects can also be obtained. That is, the first cylindrical body 31
Since the energy of the ultrasonic waves irradiated is large, the aggregation of bubbles in the liquid to be defoamed is greatly promoted, and as a result, the flow velocity of the liquid to be defoamed can be increased. In the cylindrical body 32, since the energy of the ultrasonic waves applied to the liquid to be defoamed is small, new bubbles are not generated due to cavitation effect, and the bubbles are discharged together with the liquid to be defoamed. As a result, sufficient defoaming can be performed while obtaining a high defoaming ability. Furthermore, when the viscosity of the liquid to be defoamed is high or when the flow rate of the liquid to be defoamed is supplied to the defoaming tank 3 is large, the second ultrasonic oscillator 2 is activated in the second cylindrical body 32.
It is desirable to carry out the defoaming process by increasing the diameter of the second cylindrical body 32 to reduce the descending speed of the liquid to be defoamed so that the ultrasonic wave B can push up the remaining air bubbles. . In addition, in the apparatus shown in FIGS. 3 and 4, the upper part of the first cylindrical body 31 and the second cylindrical body 32, that is, the cylindrical part
The depth d from the connecting part of the cylindrical bodies 31 and 32 is
The size is such that the flow of the degassing liquid is not disturbed.
For this purpose, it is desirable that the diameter be larger than the diameter of the cylindrical portion. Next, a specific example will be explained. <Specific example> In the apparatus shown in Figs. 3 and 4, the hot water temperature in the ultrasonic liquid bath 1 is 38°C, and the flow rate is 0.5/
6 minutes, bubble content 3cm ³ /100cm ³ , viscosity 30cp
% gelatin solution and the output of the first ultrasonic oscillator 2A was 0.7 W/cm ² and the output of the second ultrasonic oscillator 2B was 0.3 W/cm ² to examine the defoaming ability. The results are shown in the table. <Comparative Example> The defoaming ability was investigated in the same manner as in the specific example except that the output of the first ultrasonic oscillator 2A and the output of the second ultrasonic oscillator 2B were both 1 W/cm ² . The results are shown in the table. In the above, the criteria for determining the defoaming ability are to gradually increase the flow rate of the defoaming liquid and to
The critical flow rate at which bubbles appear in the degassing liquid inside the tank was used as the criterion for degassing ability.

[Table] It is thus understood that the present invention has considerably greater defoaming ability than conventional methods. As described above, according to the present invention, it is possible to provide an ultrasonic defoaming method that can significantly improve the defoaming ability, ensure defoaming, and facilitate operations such as cleaning. It is possible to provide an ultrasonic defoaming device capable of degassing.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing a conventional ultrasonic defoaming device, Fig. 2 is an explanatory view showing an example of the method of the present invention, Fig. 3 is a longitudinal cross-sectional view showing the device of the present invention, and Fig. 4 is a vertical cross-sectional view showing an example of the method of the present invention.
It is a sectional view along the - line of a figure. 100... Ultrasonic liquid bath, 101... First cylindrical body,
102...Second cylindrical body, 103...Defoaming tank, 104
...Defoaming liquid supply pipe, 105...Defoaming liquid discharge pipe, 1
06... Ultrasonic oscillator, P1... First channel, P2...
Second flow path, 1... Ultrasonic liquid tank, 2A... First ultrasonic oscillator, 2B... Second ultrasonic oscillator, 3... Defoaming tank, 31... First cylindrical body, 32... Second cylindrical body,
33... Projection plate, 4... Defoaming liquid supply pipe, 5... Defoaming liquid discharge pipe, 6... Air vent pipe, 7... Float,
8...Pipe.

Claims (1)

[Scope of Claims] 1. In an ultrasonic defoaming method in which a liquid to be defoamed is defoamed by irradiating ultrasonic waves to the liquid to be defoamed, the liquid to be defoamed is raised in a first flow path extending upward. The first step is to irradiate the defoaming liquid with ultrasonic waves with energy that produces a cavitation effect.
The degassing liquid that has passed through the first step is lowered along a second flow path that extends downward continuously from the top of the first flow path while generating energy that does not cause cavitation effect. An ultrasonic defoaming method comprising: a second step of irradiating the liquid to be defoamed with ultrasonic waves from below. 2. an ultrasonic liquid tank; a defoaming tank consisting of two conical cylindrical bodies immersed in the ultrasonic liquid tank, each of which has a lower portion expanding upward and communicating with each other at the upper part; a defoaming liquid supply pipe connected to the lower end of one of the two cylindrical bodies; a defoaming liquid discharge pipe connected to the other lower end of the two cylindrical bodies; and the defoaming tank. and a pair of ultrasonic oscillators provided below the ultrasonic defoaming device.