JPS5836252B2 - Freeze or thaw state detection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a freezing or thawing state detection device.

The applicant has previously proposed various new methods and devices for freezing and thawing fresh foods, such as fruits, vegetables, fish, meat, and other processed foods.

However, in this case, in the case of freezing and thawing, it is sufficient to cool and freeze to a desired state and temperature, regardless of the method, equipment, etc. It is sufficient to heat and thaw the temperature to a certain temperature, and excessive freezing and thawing below the specified temperature is unnecessary, or may even be harmful, and may require energy such as electric power for cooling and thawing. This only results in disadvantages accompanied by losses.

On the other hand, when we consider cooling and thawing, we find that in freezing, water turns into ice, and in thawing, ice turns to water; both are merely transformations between water and ice.

However, due to the difference in their physical states, water and ice have different rate constants for transmission, reflection, residue, or transmission of sound waves, ultrasonic waves, etc., and the speed of sound in water is different at room temperature (23-27°C). In distilled water, it is about 1.450rrv', and in seawater, it is about 1.
The speed of sound in water is approximately 3.2, while the speed of sound in water is 500 m/s.
By detecting the speed, phase difference, or absorption (attenuation) of the transmission, reflection, resistance, etc. of sound waves or ultrasonic waves through the food to be frozen or thawed, which are completely different such as 3 om/s, It is possible to detect and determine the state of freezing and thawing, in other words, the completion of freezing and freezing 1 or the completion of thawing.

Also, sound waves and ultrasound waves require two different media (gas and liquid,
When passing through liquids and solids (water and ice are also different media), there is a lot of attenuation due to reflection at the interface, and the transmission state is greatly reduced.

For example, the inside of thawing food can be considered to be a mixture of water and ice, so if this food is directly irradiated with ultrasound, the ultrasound that passes through the food will be reflected by ice chips or ice layers and its speed will be reduced. Since it changes, if a device is provided to detect the state of transmission, reflection, or transmission (absorption, attenuation), the thawing time can be easily determined accurately.

Below, the embodiment device of the present invention will be explained with reference to the drawings.
The figure is a simplified diagram of the structure of a thawing device including the device of the present invention, in which 1 is a pressure-resistant container that can be opened, closed, and sealed for thawing, into which a frozen food 2 is inserted.

Further, 3 is a MUGUTRON to which the output of a high-frequency electrical energy generator 4 is applied, giving electric energy to the frozen food 2 in the container 1 to thaw it.

On the other hand, 5 is a sonic or ultrasonic generator that directly irradiates the frozen food 2 with ultrasonic vibrations via an irradiator 6 inserted into the container 1, and captures the transmitted sonic waves or ultrasonic energy with a detector 7. Then, the amplification device 8 performs appropriate amplification, and the state of change from ice to water can be electrically detected as a change in the sound wave or ultrasonic energy transmitted through the frozen food 2.

This change is set to a certain level, and when the level falls below that level, the output of the amplifier device 8 is reduced, the relay 9 is operated, and the voltage application of the power source 10 to the device 4, which is the power source for defrosting, is stopped.

That is, the absorption of energy accompanying transmission is approximately inversely proportional to the speed of sound mentioned above.

Figure 2 shows the change in transmitted ultrasonic energy with time on the horizontal axis and time on the vertical axis.
The defrosting power is turned off to complete the defrosting process, and the food is then drained and used for cooking.

Even if the irradiator of the same sonic or ultrasonic transducer is applied directly to the food, or a substance (solid, liquid, etc.) with similar physical properties to the food is interposed between the transducer and the food. If single reflection is to be detected, the irradiator can also be used as a receiver.

In one example, 1 kW was applied to each 3 kg frozen shrimp.
2.450M. When thawing is performed by applying HZ electromagnetic waves, one shrimp can be thawed in 63 minutes by applying 5MHz ultrasonic waves separately.
In contrast, about 3 cups of thawed water was attached to the shrimp, and the temperature of the shrimp was 0°C, while the temperature of the water was 0.4°C.

Although the above is an example in which transmission is used, it is of course possible to perform detection using reflected energy, transmission speed, etc. in a similar manner.

The same goes for freezing, and you can think of it as the opposite of thawing.

As described above, the present invention detects the freezing or thawing state based on the temperature, which was difficult due to the large number of errors in judgment. The system captures and detects the state of absorption of sound waves caused by reflection, etc., and the detection is reliable.It is used for management of freezers, etc., and is used for range control and thawing display as a range with thawing degree judgment. It is also effective to use.

[Brief explanation of the drawing]

FIG. 1 is a simplified configuration diagram of an embodiment of a thawing device including the device of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between transmitted ultrasound and time. In the figure, 1 is a thawing container, 2 is a frozen food, 3 is a magnetron, 5 is a sonic or ultrasonic generator, 6 is a vibrator, 7 is a detector, and 8 is an amplifier.

Claims (1)

[Claims] 1. In a freezing or thawing device having a storage section for food objects to be frozen or thawed, an oscillator for irradiating sound waves or ultrasonic waves is provided in the storage section, and the sound waves or ultrasonic waves oscillated by the oscillator are It is characterized by being provided with a detection device for detecting a change in the transmission, reflection, or transmission state of the irradiated sound wave or the ultrasonic wave inside the frozen or thawed object of the food that has been irradiated with the ultrasonic wave. Freeze or thaw state detection device.