WO2006004116A1

WO2006004116A1 - Water-containing material freezing/thawing apparatus and method therefor

Info

Publication number: WO2006004116A1
Application number: PCT/JP2005/012407
Authority: WO
Inventors: Kenji Shindo; Kodo Kawase; Yuichi Ogawa
Original assignee: Riken
Priority date: 2004-07-05
Filing date: 2005-07-05
Publication date: 2006-01-12
Also published as: JP2006017418A

Abstract

There is provided an apparatus comprising cooling heat radiation unit (12) for cooling of or heat radiation from water-containing material (1), extremely high frequency wave (EHF) irradiation unit (14) for irradiating the water-containing material with EHF of 0.1 to 100 mm wavelength (2), EHF detector (16) for detecting of EHF (1) having transmitted the water-containing material, phase change detector (18) for computing of the level of absorption by the water-containing material from EHF irradiation output and detection output to thereby detect the state of phase change of the water-containing material, and freezing/thawing control unit (20) for controlling of the cooling heat radiation unit depending on the state of phase change detected.

Description

Specification

Apparatus and method for freezing and thawing moisture content

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an apparatus and method for freezing and thawing water-containing materials such as water and ice, foods, and DNA samples.

Explanation of related technology

[0002] It is widely known that when water is cooled, the phase changes to ice, and various physical characteristics change accordingly. Such characteristics of water and ice are disclosed in Non-Patent Documents 1 to 3, for example.

[0003] [Non-Patent Document 1] reports the measurement results of the ice optical constants at the terahertz frequency.

[Non-Patent Document 2] reports the optical constants of ice from ultraviolet to microwave.

[Non-Patent Document 3] describes general physical properties of water.

[0004] On the other hand, for example, [Patent Document 1] has been proposed as a device that utilizes changes in physical properties when phase changes to hydro ice.

[0005] The "automatic ice making device" of Patent Document 1 is a device in which a phase change detection sensor 52 for detecting a phase change of water in an ice making container 51 to ice is attached to an ice making container installation part. As shown in FIG. 1, this phase change detection sensor 52 includes an excitation electrode 54 connected to a high-frequency oscillator 53, and a detection coil for reception that receives an electromagnetic wave that is insulated from the excitation electrode and oscillates from the excitation electrode. The phase change of the water in the ice making container surrounding the receiving detection coil is captured by the change in the resonant voltage induced in the receiving detection coil or the change in the resonant frequency as a change in conductivity and dielectric constant. Is.

[0006] Non-Patent Document 1: Chun Zhang et al. "Optical constant of ice Ih crystal at terahertz frequencies", APPLIED PHYSICS LETTERS, Vol. 7 9, No. 4, 2001, P491-493

Non-Patent Document 2: Stephen G. Warren "Optical constant of ice from the ultraviolet to the microwave ", APPLIED OPTICS, Vol. 23, No. 8, 1984, P1206-1225

Non-Patent Document 3: Marvin R. Querry et al. "Water (H20) HANDBOOK OF OPTICAL CONSTANTS OF SOLIDS II, 1991, P1059-1077 [0007] Patent Document 1: Japanese Utility Model Publication No. 5-8360," Automatic Ice Maker "

[0008] When making ice from water, Patent Document 1 detects a phase change of water as a change in conductivity and dielectric constant. However, this method has a problem that it cannot detect a phase change process in which water and ice are mixed. For this reason, extra cooling was required even after the phase change, and there was a limit to further improving the ice making speed.

In addition, in the case of vegetables, fruits, meat, etc. that contain moisture in the cell membrane, the cells may be destroyed by the growth of ice crystals when icing the moisture, and the quality may be degraded. It is most desirable to keep it cool. However, in the past, such a supercooled state could not be detected.

In addition, meat, fresh fish, frozen foods, DNA samples, etc., generally need to be completely frozen in a short time when frozen, and if unfrozen parts remain, there is a risk that germs will propagate. However, in the past, it was merely rapid cooling, and there was a powerful means to confirm that the entire object was completely frozen without cutting it from the outside.

Conversely, when thawing, it was necessary to allow sufficient time for thawing so that the inner cell membrane would not be destroyed, for example, as represented by tuna. Therefore, there was a problem that it took too long to defrost.

[0009] The present invention has been developed to solve the above-described problems. In other words, the purpose of the present invention is to accurately detect the phase change state during freezing or thawing of water contained in water and ice, food, DNA samples, etc., thereby increasing the ice making speed and supercooling. To provide a device and a method for freezing and thawing moisture-containing materials that can maintain the state, confirm the frozen state of the entire object from the outside, hold the entire object immediately before thawing, and shorten the thawing time. is there.

Summary of invention

[0010] According to the present invention, a cooling and radiating device that cools or dissipates heat containing moisture, including moisture, Wavelength of 0. lmn! A millimeter wave irradiation device that emits a millimeter wave of up to 100 mm, a millimeter wave detection device that detects the millimeter wave that has passed through the moisture-containing material,

A phase change detection device for calculating the absorption amount of the moisture-containing material from the irradiation output and detection output of the millimeter wave and detecting the phase change state of the moisture-containing material;

A water-freezing and thawing device is provided, comprising: a detected phase change state force; and a cold thawing control device that controls the cooling and heat dissipation device.

[0011] Further, according to the present invention, a cooling / dissipating step for cooling or dissipating the moisture-containing material containing moisture,

Wavelength of 0. lmn! A millimeter wave irradiation step of irradiating a millimeter wave of up to 100 mm; a millimeter wave detection step of detecting the millimeter wave that has passed through the moisture-containing material;

A phase change detection step of calculating an absorption coefficient of the moisture content from the irradiation output and detection output of the millimeter wave and detecting a phase change state of the moisture content;

A detected phase change state force, and a speed control step for controlling a cooling rate or a heat release rate of the water-containing material so as to maintain the absorption coefficient within a predetermined range. Is provided.

[0012] According to the apparatus and method of the present invention, the absorption coefficient changes greatly during the phase change process. It can detect the phase change state accurately by calculating the absorption coefficient of water-containing substances using water of ~ 100mm. Therefore, it is possible to feed back the detected phase change state and maintain the absorption coefficient within a predetermined range, thereby increasing the ice making speed, maintaining the supercooled state, and confirming the complete freezing of the entire object from the outside. The entire object can be held immediately before thawing to shorten the thawing time.

According to a preferred embodiment of the present invention, the millimeter wave irradiation device includes a millimeter wave oscillator that oscillates a millimeter wave having a frequency of 100 kHz to 5 OGHz, and an oscillation that irradiates the millimeter wave toward a moisture-containing material. It consists of a horn antenna for

The millimeter wave detection device includes a reception horn antenna that receives the millimeter wave that has passed through the moisture-containing material, a power sensor that detects the received millimeter wave and converts it into an electrical signal, and the electrical signal force is also output as a millimeter wave. And a power meter for detecting

[0014] With this configuration, the entire millimeter wave having a frequency of 100 kHz to 50 GHz oscillated by a millimeter wave oscillator can be obtained. The horn antenna for oscillation can accurately irradiate the moisture content. In addition, the entire millimeter wave that has passed through the moisture-containing material can be received by the receiving horn antenna, and the detection output can be accurately detected by this force power sensor and power meter. Therefore, it is possible to minimize the millimeter waves scattered without passing through the moisture content, accurately calculate the absorption coefficient, and accurately detect the phase change state during freezing or thawing. .

[0015] As described above, the apparatus and method for freezing and thawing water-containing materials of the present invention accurately detects the phase change state during freezing or thawing of water contained in water and ice, food, DNA samples, etc. This can increase the ice making speed, maintain the supercooled state, confirm the complete freezing of the entire object from the outside, and hold the entire object immediately before thawing to shorten the thawing time. It has excellent effects such as being able to.

Brief Description of Drawings

FIG. 1 is a schematic diagram of an “automatic ice making device” of [Patent Document 1].

FIG. 2 is an overall configuration diagram of the freezing and thawing device of the present invention.

FIG. 3 is a flowchart of the freeze-thawing method of the present invention.

[Fig. 4] Relationship between water and ice absorption coefficient and wavelength.

FIG. 5 is a measurement result of an absorption coefficient according to the first embodiment of the present invention.

FIG. 6 is a measurement result of an absorption coefficient according to the second embodiment of the present invention.

FIG. 7 is a measurement result of an absorption coefficient according to the third embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the duplicate description is abbreviate | omitted.

FIG. 2 is an overall configuration diagram of the freezing and thawing device of the present invention. In this figure, the freezing and thawing device 10 of the present invention includes a cooling and radiating device 12, a millimeter wave irradiation device 14, a millimeter wave detection device 16, a phase change detection device 18, and a cold thawing control device 20.

[0019] The cooling heat dissipating device 12 includes a freezing container 12a that contains a water-containing material 1 containing water, a refrigerator 12b that cools or dissipates heat in the freezing container, and a temperature at which the temperature of the water-containing material 1 is detected. It consists of a detector 12c (for example, a thermocouple).

[0020] The millimeter wave irradiation device 14 has a water content of 1 with a wavelength of 0.1 lmn! ~ 100mm millimeter wave 2 Irradiate the target millimeter wave). In this example, the millimeter wave irradiation device 14 has a frequency of 100 kHz to 5

It consists of a millimeter wave oscillator 14a that oscillates OGHz irradiation millimeter wave 2 and an oscillating horn antenna 14b that irradiates the irradiation millimeter wave 2 toward moisture-containing materials.

The millimeter wave detection device 16 detects a millimeter wave 3 that has passed through the moisture-containing material 1 (hereinafter referred to as a transmitted millimeter wave). In this example, the millimeter wave detection device 16 includes a receiving horn antenna 16a that receives the transmitted millimeter wave 3 that has passed through the moisture-containing material 1, and a power sensor 16b that detects the received transmitted millimeter wave 3 and converts it into an electrical signal. And the converted electric signal force also comprises a parameter 16c for detecting the output of the transmitted millimeter wave 3.

[0022] The phase change detection device 18 calculates the absorption coefficient of the moisture-containing material from the irradiation outputs and detection outputs of the millimeter waves 2 and 3, and detects the phase change state of the moisture-containing material. The cold thawing control device 20 controls the detected phase change state force cooling heat dissipation device 12.

The phase change detection device 18 and the cold thawing control device 20 are, for example, P

C (PC). The detection data of the temperature detector 12c is also the cold thawing control device 20 or

Input to the PC.

[0023] FIG. 3 is a flowchart of the freeze-thaw method of the present invention. As shown in this figure, the freezing and thawing method of the present invention comprises a cooling heat release step Sl, a millimeter wave irradiation step S2, a millimeter wave detection step S3, a phase change detection step S4, and a speed control step S5.

In the cooling and heat radiation step S 1, the water-containing material 1 containing water is cooled or radiated by the cooling and heat radiating device 12.

In the millimeter wave irradiation step S2, the water content 1 is irradiated with the millimeter wave 2 (irradiation millimeter wave) having a wavelength of 0.1 mm to LOOmm by the millimeter wave irradiation device 14.

In the millimeter wave detection step S3, the millimeter wave detection device 16 detects the millimeter wave 3 (transmitted millimeter wave) that has passed through the moisture-containing material 1.

[0025] In the phase change detection step S4, the phase change detection device 18 calculates the absorption amount of the moisture-containing substance 1 from the irradiation outputs and detection outputs of the millimeter waves 2 and 3, and detects the phase change state of the moisture-containing substance. In control step S5, the cooling or radiating rate of the moisture-containing material 1 is maintained by the cold thawing control device 20 so as to maintain the absorption coefficient within a predetermined range from the detected phase change state. To control.

FIG. 4 is a graph showing the relationship between the absorption coefficient of water and ice and the wavelength. In this figure, the horizontal axis represents the wavelength and frequency of electromagnetic waves, and the vertical axis represents the absorption coefficient. The solid line in the figure indicates solid (ice), and the alternate long and short dash line indicates liquid (water).

From this figure, it can be seen that the absorption coefficient of water and ice is greatly different in the region where the wavelength is about 100 / ζ πι (0.1 mm) or more. For example, the absorption coefficient of ice and water at 35GHz are each ^{42 cm "1, 7 X 10-} 3 cm- 1 mm, there are about 6000-fold difference.

Note that when the wavelength exceeds 100 mm, the ratio of encircling without passing through the moisture-containing substance 1 increases, and the measurement accuracy decreases.

[0027] From Fig. 4, it can be predicted that the moisture-containing material containing moisture has a large absorption difference between the solid phase and the liquid phase. The present invention has been devised with a focus on the difference in absorption coefficient of the water-containing material.

That is, according to the above-described apparatus and method of the present invention, the wavelength at which the absorption coefficient changes greatly during the phase change process is 0. lmn! Since a millimeter wave of ˜100 mm is used, the absorption coefficient of moisture-containing material 1 containing moisture can be calculated accurately and its phase change state can be detected accurately. Therefore, it is possible to feed back the detected phase change state and maintain the absorption coefficient within a predetermined range, thereby increasing the ice making speed, maintaining the supercooled state, and completely freezing the entire object from the outside. It can be confirmed and the entire object can be held immediately before thawing to shorten the thawing time.

Hereinafter, examples of the present invention will be described.

Example 1

[0030] Using the freezing and thawing apparatus 10 of the present invention shown in FIG. 2, pure water was tested as a sample. In this test, a sample (pure water) was placed in a polyethylene terephthalate cell with an optical path length of 1 mm, and the millimeter wave transmission during phase transition from liquid to solid was measured. The temperature of the sample was measured with a thermocouple. Each measurement was repeated every 90 seconds.

[0031] In this test, a gun oscillator (TERA BEAM, oscillation frequency 35GHZ) was used as the millimeter oscillator (mmW-Source). The maximum output power is 10mW and continuous oscillation is possible. The rated input voltage is 6.5V. The horn antenna used was Custom MZW H022R, the gain was 24 dBi, and the measured full width at half maximum was 14.53 deg.

In the reception system, the power transmitted through the horn antenna is a waveguide? After coaxial conversion, detection was performed with a power sensor (Anritsu MA2475A) and a power meter (Anritsu ML2437) which are diode waveform wattmeters. The dynamic range of detection sensitivity was 90 dB (-70 to +20 dBm), and the measurable frequency range was 100 kHz to 50 GHz.

FIG. 5 shows the measurement results of the absorption coefficient obtained in this test. In this figure, the horizontal axis is temperature and the vertical axis is absorption coefficient.

As shown in Fig. 5, when the liquid at about 16 ° C (pure water) was also cooled down at point A, the temperature dropped to 3.1 ° C once at point B, and an overcooled state was observed. After that, the supercooling was instantaneously released at point C, and when it returned to 0 ° C again, it was thought that the phase displacement occurred and it became a solid phase. Then, the temperature was kept constant for about 40 minutes (1. 8 ° C) At this point, the absorption coefficient continued to drop to point D. Next, at point D, when the absorption coefficient reached about -15 cm ¹ , the temperature began to drop again. At the same time, the absorption coefficient gradually decreased. After that, the absorption coefficient became constant from 13 ° C (point E) to the ultimate cooling temperature of the freezer 20 ° C (point F).

[0033] In the liquid phase state (point A to point B) until supercooling, it was confirmed that the absorption coefficient decreased with temperature change. From this result, it can be seen that the liquid phase at 0-5 ° C has a slope of 0.8c.

It can also be seen that after the absorption coefficient is supercooled (point B) and then changed to a solid (point C), the absorption coefficient changes greatly. From this situation, it was confirmed that the state of phase change from the liquid phase to the solid phase and the frozen state can be clearly discriminated by the transmission amount of the millimeter wave, that is, the absorption coefficient.

It can also be seen that the absorption coefficient decreases gradually until it reaches -13 ° C (E point) and then stabilizes until -20 ° C (F point). This is thought to be due to the stable molecular structure of water molecules as ice.

At present, there is no other simple method for confirming internal freezing by measuring the amount of permeation. Therefore, this technique can be applied to monitoring during freezing and thawing. Example 2

Next, a mixed water having a sucrose concentration of 10% was used as a sample, and the sample was put in a polyethylene terephthalate cell having the same optical path length of 1 mm as in the first example, and the same test was performed. Mixed water with a sucrose concentration of 10% simulates vegetables and fruits.

FIG. 6 shows the measurement results of the absorption coefficient obtained in this test. In this figure, the horizontal axis is temperature and the vertical axis is absorption coefficient. From this figure, it can be seen that in the cooling process of A, B, C, and D, the supercooling release occurs instantaneously through the supercooled state (point B) as in the case of pure water. In this example, it was also confirmed that the absorption coefficient decreases with decreasing temperature, even in the solid phase, until the C point force reaches the D point.

From this result, it is understood that by maintaining the absorption coefficient within a predetermined range (in this example, about 10 to 20 cm), it is possible to hold vegetables, fruits, meat, etc. in a supercooled state immediately before the phase change. Power.

Example 3

[0036] The same test as in the first example was performed using minced meat with a thickness of about 1 cm as a sample. Minced meat simulates meat, fresh fish, frozen food, DNA samples, and so on.

FIG. 7 shows the measurement results of the absorption coefficient obtained in this test. In this figure, the horizontal axis is temperature and the vertical axis is absorption coefficient. From this figure, in the cooling process of A, B, C, D, a clear supercooling state is not detected, but the gel state (points A to B) and the solid state (points C to D) are It was confirmed that the change characteristics of the absorption coefficient are completely different.

From Fig. 7, when the unfrozen part remains, the absorption coefficient shows an intermediate value between the gel state and the solid state, so it can be confirmed that the entire object is completely frozen without external force cutting. I understand that I can do it.

Conversely, when thawing, the absorption coefficient in the solid state (C point to D point) is maintained, so that the thawing time can be significantly shortened while keeping the inner cell membrane from being destroyed.ゎゎ.

It should be noted that the present invention is not limited to the above-described examples and embodiments, and various modifications can be made without departing from the scope of the present invention.

Claims

The scope of the claims

[1] a cooling / dissipating device that cools or dissipates moisture containing moisture, and

Wavelength of 0. lmn! A millimeter wave irradiation device that emits a millimeter wave of up to 100 mm, a millimeter wave detection device that detects the millimeter wave that has passed through the moisture-containing material,

A water-freezing and thawing device, comprising: a detected phase change state force;

[2] The millimeter wave irradiation apparatus includes a millimeter wave oscillator that oscillates a millimeter wave having a frequency of 100 kHz to 50 GHz.

An oscillation horn antenna that irradiates the millimeter wave toward the moisture-containing material, the millimeter-wave detection device comprising: a reception horn antenna that receives the millimeter wave that has passed through the moisture-containing material; and the received millimeter wave 2. The moisture-containing freezing and thawing device according to claim 1, comprising a power sensor that detects and converts an electric signal into an electric signal, and a power meter that detects an output of millimeter waves.

[3] a cooling / dissipating step for cooling or dissipating moisture containing moisture,

A detected phase change state force, and a speed control step for controlling a cooling rate or a heat release rate of the water-containing material so as to maintain the absorption coefficient within a predetermined range. .