JPH07291395A - Device for removing foam in container head space - Google Patents

Abstract

PURPOSE:To obtain a marked defoam effect, by reflecting ultrasonic waves from both the back and front of a vibrating plate. CONSTITUTION:A device for removing foam in a container head space is provided with a ultrasonic wave generator toward the liquid level of a drink container, over a passage along which a container 1 is passed till it is stoppered after filled, in a drink-filling machine. In this device, a horn 12 at the front end of the ultrasonic wave generator is provided with a rectangular vibrating plate 51, on its both sides, back and front, are reflecting plates 61a and 61b for reflecting radiated sound waves, and the reflecting plate 61a has the curvature of the reflecting surface so that paths 63a, 63b, and 63c of the radiated ultrasonic waves from the vibrating plate 51 to the mouth of the container 1 are all equal. Therefore, the sound waves reaching the mouth of the container 1 maintain the same phase, and the paths 63d, 63e, and 63f of ultrasonic waves radiated from the reflecting plate 61b are shifted with respected to the paths 63a, 63b, and 63c, 1/2 distance in the wavelength of a sound wave transmitted through air, thereby intensifying magnitude together with the ultrasonic waves radiated from the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defoaming device for a container headspace in a system for filling and sealing beverages such as beer, fruit juice, milk and the like (including caps such as crowns and caps and sealing of container mouths). It is a thing.

[0002]

2. Description of the Related Art When a container is filled with a beverage such as beer, fruit juice or milk, it is important for quality control of the beverage to remove the residual air in the head space above the container. When supersaturated carbon dioxide gas is released as a large number of bubbles such as beer and carbonated drinks, when the bubbles enter the seal part of the container, they become dry and become sugar cement, and the cup sticks and opens. There is a possibility that it may become difficult or cause the generation of microorganisms. On the other hand, the fact is that a considerable amount of bubbles are generated in the container head space after filling due to the mechanism of the filling device. Especially when filling a container of beer or carbonated drink, the state of the foam is as shown in FIG.
Has small bubbles A and large bubbles B. The small bubbles A are filled under pressure, and when released into the atmosphere, the carbon dioxide gas dissolved in the beverage 2 is released because it becomes supersaturated, so that most of the inside is carbon dioxide gas, It will increase or decrease when the conditions of () are changed (filling speed, beverage temperature, etc.). Further, the large-sized bubbles B are generated by the air bubbles trapped during the filling floating, and contain a large amount of air in the gas phase portion inside. From the above, the defoaming of the foam B can be performed in the air removal for quality control, and the capacity of the filling machine can be improved by increasing the filling speed, and the filling can be performed from the container when the temperature of the beverage 2 is close to room temperature for energy saving. The defoaming of overflowing foam A is required.

Next, a bubble eliminating device proposed in Japanese Patent Application No. 5-270313 will be described with reference to FIGS. 4, 5, 6, 7 and 8. First, in FIG. 8, the bubble eliminating device 6 is provided between the filler 3 with which the beverage 1 is filled in the container 1 and the upper part of the passage through which the container 1 is conveyed between the sealing device 4.
The bubble eliminator 6 includes an ultrasonic vibration oscillator 11 shown in FIG. 6, a diaphragm 51 attached to a horn 12 and a fastening member 52 such as a screw, and a path 63 of ultrasonic waves emitted from the diaphragm 51.
It is composed of a reflection plate 61 which reflects and collects a, 63b and 63c. The ultrasonic vibration generated by the oscillator 11 propagates to the diaphragm 51 via the horn 12 and vibrates in the mode 53 according to its shape and material. Further, the ultrasonic waves 63a, 63b, 63c emitted from the vibrating plate 51 and reflected by the reflecting plate 61 reach the bubbles A, B on the upper part of the traveling container 1. In addition, the reflection plate 61
In order to prevent interference and diffusion of radiated ultrasonic waves, partition plates 62 are attached at equal intervals according to the vibration mode 53 of the vibration plate 51.

The vibration generated by the oscillator 11 propagates through the horn 12 fixed with screws or the like and is transmitted to the diaphragm 51 fixed with screws 52 or the like. By the way, at this time, the diaphragm vibrates flexibly with both ends free, and resonates when the length L is expressed by the following equation.

[Equation 1] mi is a reference constant, and is calculated from cosmi · coshmi = 1. Further, i is the order of the vibration mode (i = 1, 2, 3, ...
・), R is the radius of gyration, and the thickness is S in the case of a rectangular cross section.
Then, a value of 0.289 S is generally given. C is the sound velocity in the material of the diaphragm, w is the angular frequency, and w = 2πf from the vibration frequency f. Here, if the order of the vibration mode is set to an odd number, the mounting portion of the horn and the vibration plate becomes an antinode of vibration and resonates. The antinode of vibration of the diaphragm occurs in the same number as the order of the vibration mode, and air vibration is induced in that part to generate ultrasonic waves. As described above, when the length of the diaphragm 51 is dimensioned so that an odd number of vibration modes 53 are generated, ultrasonic waves are emitted from the antinode of the vibration.

The ultrasonic waves emitted here are amplified by setting the same paths 63a to 63c leading to the mouth of the container 1 or by making the difference of an integral multiple of the wavelength, and a strong sound wave is generated. Occurs at the mouth of. Again foamy container 1
Is a conveying means such as the conveyor 14 in the direction of arrow 13 (FIG. 7).
To pass directly below the diaphragm 51 and the reflector 61. Then, when the foamed container 1 passes directly under the device emitting the ultrasonic waves, the bubbles A and B receive the sound pressure of the ultrasonic waves and disappear sequentially from above. The reason why bubbles are erased by ultrasonic waves is that when the air vibration generated in the diaphragm 51 reaches the bubble upper surface, it undergoes a sudden deformation due to pressure change, and the film forming the bubble becomes thin and breaks.

[0006]

However, the ultrasonic bubble erasing device disclosed in Japanese Patent Application No. 5-270313 of the prior art is used for erasing only one side of the ultrasonic wave emitted from the diaphragm 51. Absent. As can be seen from the vibration mode 53 (FIG. 5) of the diaphragm 51, the emission of ultrasonic waves is
The light is radiated not only from the front surface of the reflection plate 61 but also from the back surface thereof. The ultrasonic waves radiated from the back surface of the diaphragm 51 have not been conventionally used for bubble elimination. An object of the present invention is to provide an apparatus for eliminating bubbles in a container head space having a large defoaming effect by providing an ultrasonic oscillator and radiating ultrasonic waves from both front and back surfaces of a diaphragm.

[0007]

For this reason, the present invention is directed to a beverage filling machine, in which the container is superposed above the passage through which the container is filled between the filling of the beverage liquid and the closing of the liquid, toward the liquid level of the beverage container. A bubble elimination device for a container head space provided with an ultrasonic wave oscillator, comprising a rectangular vibration plate at the horn portion at the tip of the ultrasonic wave oscillator and plates for reflecting radiated sound waves on both front and back sides thereof. In addition, the path of the ultrasonic waves emitted from the vibration plate to the container mouth via the reflection plate is deviated by ½ of the wavelength of the air sound waves on the front and back of the vibration plate. Is the means of.

[0008]

The vibration generated by the ultrasonic oscillator propagates to the solid and is transmitted to the horn to vibrate the rectangular diaphragm attached to the tip. Then, when a container with a narrow mouth, such as a bottle after filling, passes under the diaphragm vibrating by the action of the ultrasonic oscillator, the ultrasonic waves emitted from the front and back of the diaphragm are combined at the mouth of the container. Then, the sound waves are strengthened to enter the container and the bubbles are erased. In the case of beer filling, bubbles containing air are extinguished by ultrasonic waves, and then the head space of the container is filled with carbon dioxide gas and capped, thereby reducing the amount of air remaining in the head space. Further, since the bubbles tending to overflow from the mouth of the container are extinguished, it is possible to prevent the cap from sticking to the sugar cement after sealing and to prevent the generation of microorganisms, and it is possible to eliminate the insufficient filling amount of the beverage liquid caused by spilling. Further, since the sound waves are concentrated by the reflector and the sound waves from the front surface and the back surface of the diaphragm are combined, the ultrasonic waves generated even in a container having a narrow mouth can be efficiently used. In addition, since the ultrasonic wave generation region can be expanded by increasing the length of the diaphragm, a plurality of oscillators are not required.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view of a container headspace bubble eliminating apparatus according to an embodiment of the present invention, and FIG. The bubble elimination device shown in FIGS. 1 and 2 is arranged at the installation position of the conventional bubble elimination device 6 shown in FIG. 8, and the oscillator 11 in the device is provided with a means (not shown) for the passage of the container 1. It is installed at the top. Further, the oscillator 11, the horn 12, and the diaphragm 5
1, the fastening member 52, the reflection plate 61a (61 in FIG. 6), and the partition plate 62a (62 in FIG. 6) are the same as those in the conventional device of FIG. A feature of the present invention is that a reflecting plate 61b and a partition plate 62b are installed opposite to each other on the opposite side of the reflecting plate 61a with the vibrating plate 51 sandwiched by means not shown.

The one reflecting plate 61a is a passage 63 extending from the vibrating plate 51 to the mouth of the ultrasonic container 1.
The curvatures of the reflecting surfaces are designed so that a, 63b, and 63c are equal to each other, so that the phases of the sound waves reaching the mouth of the container 1 are kept in phase and the synthetic sound waves are strengthened. On the other hand, the paths 63d, 6 of the radiated ultrasonic waves of the other reflection plate 61b.
3e and 63f determine the curvature of the reflection plate 61b so that they are equal to each other, as described above.
The distance of ½ of the wavelength of the sound wave propagating in the air expressed by the following equation is shifted with respect to b and 63c so as to mutually strengthen the ultrasonic wave radiated from the surface. That is,

Where λ is the wavelength of the sound wave, C is the speed of sound propagating in the air,
f: The excitation frequency of ultrasonic waves. Where C = 340m / s,
If f = 20KHZ, λ / 2 = 8.5mm, which is sufficient.

The paths 63a, 63 for the one of the radiated ultrasonic waves
The other reflection plate 61 provided on the opposite side to b and 63c.
The paths 63d, 63e, 63f in FIG.
The reason why it is set to one-half is that, as can be seen in the generated vibration mode 53, ultrasonic waves having a phase difference of 180 ° are radiated on the front and back sides of the vibration plate 51, so that the paths 63a, 63 are separated.
b, 63c and the passages 63d, 63e, 63f are equal,
Alternatively, when the wavelengths are shifted by an integral multiple of the wavelength, the sound waves interfere with each other and are cancelled. On the other hand, by shifting the distance of 1/2 wavelength,
On the contrary, the ultrasonic waves radiated from the front and back of the diaphragm 51 strengthen each other to raise the sound wave level.

[0012]

As described above in detail, according to the present invention, since only the sound wave enters the container, it is easy to sanitize the device and the work environment is not polluted. There is. On the other hand, the defoaming power can be adjusted easily by adjusting the output of the ultrasonic oscillator, and even if the moving speed of the container increases, one oscillator can radiate ultrasonic waves to a wide area, reducing the device cost. Can be achieved. Further, since the sound waves are concentrated on the reflector, the ultrasonic waves generated even in a container having a narrow mouth can be efficiently used. Further, according to the present invention, by providing a rectangular vibration plate on the horn portion at the tip of the ultrasonic oscillator and a plate that reflects radiated sound waves on both front and back sides, the vibration is radiated from both front and back surfaces of the vibration plate. The sound pressure level is amplified by synthesizing the sound waves by shifting the path of the ultrasonic waves reaching the container mouth by ½ of the wavelength of the air sound waves on the front and back sides. The speed of sound C in the air changes depending on the temperature.

[Equation 3] Here, Co is 331.45 m / s at the sound velocity of t = 0 ° C, and t is the temperature ° C. Even if there is an error in the path length and a change in the speed of sound, if the phase difference between the sound waves is not 180 °, the combined sound waves will always strengthen each other, that is, will be amplified to exhibit a defoaming effect. For example,

[Equation 4]

(5) A = a + b cos α, B = b sin α

[Brief description of drawings]

FIG. 1 is a side view showing a bubble elimination device for a container head space according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a cross-sectional view showing a foamed state in the container immediately after filling.

FIG. 4 is an explanatory diagram of vibration modes of the diaphragm.

FIG. 5 is a cross-sectional view of a vibration mode of a vibration plate and a reflection plate portion.

FIG. 6 is a side view showing a conventional container headspace bubble elimination device.

FIG. 7 is a plan view of FIG.

FIG. 8 is a layout view of a bubble elimination device in a container head space.

[Explanation of symbols]

1 container 11 oscillator 12 horn 51 diaphragm 61a, 61b reflector 62a, 62b partition plate 63a, 63b, 63c, 63d, 63e, 63f path of radiated ultrasonic wave

Claims (2)

[Claims] 1. In a beverage filling machine, an ultrasonic oscillator is provided toward a liquid surface of the beverage container above a passage through which the container is filled after filling the beverage liquid and before being sealed. A bubble elimination device for a container head space, characterized in that a rectangular vibration plate is provided at a horn portion at the tip of an ultrasonic oscillator, and plates for reflecting radiated sound waves are provided on both front and back sides thereof. . 2. The bubble eliminator for a container head space according to claim 1, wherein the path of the ultrasonic waves emitted from the vibrating plate to the container opening via the reflecting plate is the front and back of the vibrating plate and is the wavelength of the air acoustic wave. The defoaming device for the container head space, characterized in that it is offset by half.