Thawing device and thawing method

Abstract

To provide a thawing device capable of shortening a thawing time and improving a thawing yield by automatic control, and to provide a thawing method.SOLUTION: A surface temperature measured by a surface temperature measurement device 2 is input during operation of a steam magnetic valve 4 of a first steam blower by a control device 9, and when the surface temperature reaches an upper limit stored in upper limit storage means, a cooling magnetic valve 6 of a cooler is operated. An internal temperature measured by an internal temperature measurement device 3 is input, and when the internal temperature is decreased from a maximum temperature stored in maximum temperature storage means by a prescribed temperature or more, a steam motor valve 5 of a second steam blower is operated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thawing device and a thawing method for frozen foods.

Background Art

[0002] As a thawing device and a thawing method for frozen foods such as meat, there is a technique of measuring the central temperature of the frozen food and controlling the thawing atmosphere temperature. However, in this technique, the surface temperature of the frozen food may become too high, for example, 10°C or more, which may have an adverse effect on the quality. As a conventional thawing device, a temperature sensor for measuring the surface and central temperatures is provided near the product to be thawed, and based on the measured values, the air temperature or thawing temperature, thawing time, amount of water vapor used, etc. are controlled to construct optimal thawing conditions (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the thawing device described in Patent Document 1, since a specific control method has not been established, it is necessary to find an optimal control method by trial and error, and there is a problem that it is difficult to control with a short thawing time and a good thawing yield.

[0005] The present invention has been made paying attention to such problems, and an object thereof is to provide a thawing device and a thawing method capable of shortening the thawing time and improving the thawing yield by automatic control.

Means for Solving the Problems

[0006] In order to achieve the above object, a thawing device according to the present invention includes a thawing chamber for storing and thawing frozen food, a surface temperature measuring device for measuring the surface temperature of the frozen food, an internal temperature measuring device for measuring the internal temperature of the frozen food, a first steam blower for sending steam into the thawing chamber, a second steam blower for sending steam into the thawing chamber, and a cooling device for cooling the inside of the thawing chamber. The thawing device further includes an upper limit storage means for storing an upper limit value of the surface temperature, a maximum temperature storage means for storing the highest temperature after the start of measurement of the internal temperature measured by the internal temperature measuring device. During operation of the first steam blower, the surface temperature measured by the surface temperature measuring device is input, and when the surface temperature reaches the upper limit value stored in the upper limit storage means, the cooling device is operated. The internal temperature measured by the internal temperature measuring device is input, and when the internal temperature drops by a predetermined temperature or more from the highest temperature stored in the maximum temperature storage means, the second steam blower is operated Without the surface temperature exceeding the upper limit value, until the internal temperature reaches a predetermined thawing temperature, thawing is performed by intermittently heating while cooling the inside of the thawing chamber and a control device.

[0007] A thawing method according to the present invention includes a first heating step of sending steam into a thawing chamber storing frozen food, a surface temperature measuring step of measuring the surface temperature of the frozen food, an internal temperature measuring step of measuring the internal temperature of the frozen food, a cooling step of lowering the temperature of the thawing chamber when the surface temperature reaches a predetermined upper limit value, and when the internal temperature drops by a predetermined temperature or more from the highest temperature after the start of measurement of the internal temperature Send steam into the inside of the thawing chamber a second heating step of raising the temperature of the thawing chamber a step of thawing by intermittently heating while cooling the inside of the thawing chamber until the surface temperature does not exceed the upper limit value and the internal temperature reaches a predetermined thawing temperature and is characterized by including these steps.

[0008] In the thawing device and thawing method according to the present invention, steam is sent into the thawing chamber storing the frozen food, the temperature of the thawing chamber is lowered when the surface temperature of the frozen food reaches a predetermined upper limit value, and the temperature of the thawing chamber is raised when the internal temperature drops by a predetermined temperature or more from the highest temperature after the start of measurement of the internal temperature, whereby it is possible to shorten the thawing time and improve the thawing yield.

[0009] In the thawing device according to the present invention, it is preferable that the control device stops the first steam blower and the second steam blower when the internal temperature reaches a predetermined thawing temperature. In the thawing method according to the present invention, it is preferable to have an end step of stopping the first heating step and the second heating step when the internal temperature reaches a predetermined thawing temperature. In the thawing device and the thawing method according to the present invention, when the internal temperature reaches a predetermined thawing temperature, heating is stopped and thawing is terminated.

[0010] The thawing device according to the present invention preferably includes a fan that blows air inside the thawing chamber and a germicidal lamp that lights inside the thawing chamber in conjunction with the fan. In this case, the fan can suppress temperature unevenness inside the thawing chamber. Also, the inside of the thawing chamber can be sterilized by the germicidal lamp while the fan is operating.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a thawing device and a thawing method capable of shortening the thawing time and improving the thawing yield by automatic control.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 shows a thawing device according to an embodiment of the present invention. The thawing device includes a thawing chamber, an indoor temperature measuring device 1, a surface temperature measuring device 2, an internal temperature measuring device 3, a steam solenoid valve 4, a steam motor valve 5, a cooling solenoid valve 6, two fans 7, a germicidal lamp 8, and a control device 9.

[0014] The thawing chamber is a sealable room for storing and thawing frozen foods (thawed products) and has a door for entry and exit. The indoor temperature measuring device 1 is composed of a sensor provided inside the thawing chamber for measuring the temperature inside the thawing chamber. The surface temperature measuring device 2 is composed of a sensor for measuring the surface temperature of the frozen food. The internal temperature measuring device 3 is composed of a sensor for measuring the internal temperature of the frozen food. The internal temperature is preferably the temperature at or near the center of the frozen food. The steam solenoid valve 4 constitutes a first steam blower for sending steam into the thawing chamber. The steam motorized valve 5 constitutes a second steam blower for sending steam into the thawing chamber. The cooling solenoid valve 6 constitutes a cooling device for cooling the inside of the thawing chamber. The fan 7 is configured to blow air inside the thawing chamber. The germicidal lamp 8 is configured to light inside the thawing chamber in conjunction with the fan 7. As shown in FIG. 1, the thawing device further includes a converter 10, an inverter 11, a relay 12, a recorder 13, a direct medium coil 14, a pause switch 15, and an emergency stop switch 16.

[0015] The control device 9 is composed of a programmable logic controller having a memory. The control device 9 functionally has an upper limit storage means and a maximum temperature storage means. The upper limit storage means stores the upper limit value of the surface temperature of the frozen food. The maximum temperature storage means stores the maximum temperature after the start of measurement of the internal temperature measured by the internal temperature measuring device 3. During the operation of the first steam blower, the control device 9 inputs the surface temperature measured by the surface temperature measuring device 2 and activates the cooling device when the surface temperature reaches the upper limit value stored in the upper limit storage means. Also, the control device 9 inputs the internal temperature measured by the internal temperature measuring device 3 and is configured to activate the second steam blower when the internal temperature drops by a predetermined temperature or more from the maximum temperature stored in the maximum temperature storage means. The control device 9 is configured to stop the first steam blower and the second steam blower when the internal temperature reaches a predetermined thawing temperature. The control device 9 is connected to a touch panel display 17.

[0016] Specifically, the following control is performed by the control device 9. (1) Fan control It is turned on in conjunction with the thawing operation started by the operation start switch or schedule setting of the touch panel display 17. During the thawing operation, the fan 7 is always turned on. The frequency of the inverter 11 is varied according to an arbitrary time setting to change the air volume of the two fans 7. The operation of the fan 7 is interlocked with the opening and closing of the door of the thawing chamber. When the door is closed, the fan 7 is turned on, and when the door is open, the fan 7 is turned off. (2) Cooling solenoid valve control It is turned on in conjunction with the thawing operation started by the operation start switch or schedule setting of the touch panel display 17. After the internal temperature of the frozen food reaches the operation completion temperature, it shifts to the cold storage operation and performs on / off control according to the cold storage set temperature. When an abnormality occurs in the cooling device, the cooling solenoid valve 6 is turned off.

[0017] (3) Steam solenoid valve control It is turned on in conjunction with the thawing operation started by the operation start switch or schedule setting of the touch panel display 17. After the internal temperature of the frozen food reaches the predetermined thawing temperature, it is turned off. (4) Steam motorized valve control It is turned on in conjunction with the thawing operation started by the operation start switch or schedule setting of the touch panel display 17. Thereafter, on / off control is performed according to the set value of the room temperature measuring device 1 (heating control). When the surface temperature of the frozen food reaches the surface temperature set value, it is turned off. After reaching the hysteresis, it returns to on / off by the indoor temperature control of the thawing chamber (cascade control). Even when the internal temperature of the frozen food drops by a predetermined temperature or more from the current maximum temperature before reaching the hysteresis, it also returns to on / off control. The predetermined temperature is set in the range of 0.1 to 1.0 °C. After the internal temperature of the frozen food reaches the predetermined thawing temperature, it is turned off.

[0018] (5) Timer operation Measure the operating time by the surface temperature measuring device 2 and the internal temperature measuring device 3, and reflect it in the timer operation. The counting of the timer is performed according to the measured temperature of the surface temperature measuring device 2. Count 1 to 10 cycles each of the heating operation time count (TW) by the heating control and the cooling operation time count (TC) by the cascade control, and save them to the memory used in the timer operation. Also, save the count (T ALL) of the operation time until shifting to the cold storage operation to the memory used in the timer operation. During the heating operation (TW) by timer control, turn on the steam solenoid valve 4, the steam motor valve 5, the cooling solenoid valve 6, and the fan 7, and perform on / off control of the steam motor valve 5 according to the set value of the room temperature measuring device 1. During the cooling operation (TC) by cascade control, turn on the cooling solenoid valve 6 and the fan 7. After counting up the operation time count (T ALL) until shifting to the cold storage operation, shift to the cold storage operation. In the cold storage operation, turn on the cooling solenoid valve 6 and the fan 7, and perform on / off control of the cooling solenoid valve 6 according to the cold storage set temperature. (6) Others The sterilization lamp 8 is turned on in conjunction with the operation of the fan 7. However, the linkage to the fan 7 and the linkage to the door opening and closing can be arbitrarily set from the touch panel display 17. The defrost setting of the cooling coil can be arbitrarily set from the touch panel display 17. Various alarms and operation settings can be arbitrarily set from the touch panel display 17. However, important settings related to the operation are protected by a password.

[0019] Perform thawing by the following thawing method using a thawing device. The frozen food (thawed product) to be thawed can be any frozen food, and in addition to frozen foods, chilled foods can also be used. Examples of frozen foods include frozen beef, pork, poultry, and other meats.

[0020] Start the thawing operation by operating the start switch of the touch panel display 17 or by schedule setting. As shown in Fig. 2, open the steam solenoid valve 4 of the first steam blower device and send steam into the thawing chamber storing the frozen food (the first heating step). Set the ambient temperature inside the thawing chamber to a predetermined temperature (for example, 30°C) in advance. The fan 7 operates in conjunction with the thawing operation. Keep the fan 7 operating constantly during the thawing operation. Vary the frequency of the inverter 11 according to an arbitrary time setting to change the air volume of the two fans 7. The fan 7 operates in conjunction with the opening and closing of the door of the thawing chamber, operates when the door is closed, and stops when the door is open. Measure the surface temperature of the frozen food with the surface temperature measuring device 2 (surface temperature measuring step). Measure the internal temperature of the frozen food with the internal temperature measuring device 3 (internal temperature measuring step). When the surface temperature reaches a predetermined upper limit value (for example, 10°C), the cooling device opens the cooling solenoid valve 6 to lower the temperature inside the thawing chamber (cooling step).

[0021] When the internal temperature drops by a predetermined temperature (for example, 0.1°C) or more from the highest temperature after the start of measurement of the internal temperature, the second steam blower device opens the steam motor valve 5 to send steam into the thawing chamber and raise the temperature of the thawing chamber. (Second heating step) While cooling, perform intermittent heating until the surface temperature does not exceed the upper limit value (for example, 10°C) and the internal temperature reaches the predetermined thawing temperature (for example, 0°C), and the thawing progresses. When the internal temperature reaches the predetermined thawing temperature (for example, 0°C), close the steam solenoid valve 4 of the first steam blower device and the steam motor valve 5 of the second steam blower device to stop the first heating step and the second heating step (ending step). Next, shift to the cold storage operation, and intermittently open and close the cooling solenoid valve 6 with the cooling device.

[0022] Next, the operation will be described. In the thawing method using the thawing device according to the embodiment of the present invention, steam is sent into the thawing chamber storing the frozen food, the temperature of the thawing chamber is lowered when the surface temperature of the frozen food reaches a predetermined upper limit value, and the temperature of the thawing chamber is raised when the internal temperature drops by a predetermined temperature or more from the highest temperature after the start of measurement of the internal temperature, whereby the thawing time can be shortened and the thawing yield can be improved. When the internal temperature reaches the predetermined thawing temperature, the heating can be stopped and the thawing can be terminated. Also, the temperature unevenness inside the thawing chamber can be suppressed by the fan 7. The inside of the thawing chamber can also be sterilized by the sterilizing lamp 8 during the operation of the fan 7. By the thawing method using the thawing device according to the embodiment of the present invention, the thawing time of the frozen food can be shortened to about 20 to 30% (for example, from about 14 hours to about 10.5 hours), and the thawing yield can also be improved to 1.5 to 2.0%.

Description of Reference Numerals

[0023] 1 Indoor temperature measuring device, 2 Surface temperature measuring device, 3 Internal temperature measuring device, 4 Steam solenoid valve, 5 Steam motorized valve, 6 Cooling solenoid valve, 7 Fan, 8 Sterilizing lamp, 9 Control device, 10 Converter, 11 Inverter, 12 Relay, 13 Recorder, 14 Direct medium coil, 15 Temporary stop switch, 16 Emergency stop switch, 17 Touch panel display

Claims

1. A thawing chamber for storing and thawing frozen food, A surface temperature measuring device for measuring the surface temperature of the frozen food, An internal temperature measuring device for measuring the internal temperature of the frozen food, A first steam blower for sending steam into the thawing chamber, A second steam blower for sending steam into the thawing chamber, A cooling device for cooling the inside of the thawing chamber, and Upper limit storage means for storing the upper limit value of the surface temperature, Highest temperature storage means for storing the highest temperature after the start of measurement of the internal temperature measured by the internal temperature measuring device, During the operation of the first steam blower, the surface temperature measured by the surface temperature measuring device is input, and when the surface temperature reaches the upper limit value stored in the upper limit storage means, the cooling device is operated. The internal temperature measured by the internal temperature measuring device is input, and when the internal temperature drops by a predetermined temperature or more from the highest temperature stored in the highest temperature storage means, the second steam blower is operated. Until the surface temperature does not exceed the upper limit value and the internal temperature reaches a predetermined thawing temperature, a control device that intermittently heats while cooling the inside of the thawing chamber for thawing, A thawing device characterized by comprising.

2. The control device stops the first steam blower and the second steam blower when the internal temperature reaches a predetermined thawing temperature, The thawing device according to claim 1, characterized in that.

3. A fan for blowing air inside the thawing chamber, A germicidal lamp that lights up inside the thawing chamber in conjunction with the fan, The thawing device according to claim 1 or 2, characterized by comprising.

4. A first heating step of sending steam into the thawing chamber storing the frozen food, A surface temperature measuring step of measuring the surface temperature of the frozen food, An internal temperature measuring step of measuring the internal temperature of the frozen food, A cooling step of lowering the temperature of the thawing chamber when the surface temperature reaches a predetermined upper limit value, A second heating step of sending steam into the thawing chamber to raise the temperature of the thawing chamber when the internal temperature drops by a predetermined temperature or more from the highest temperature after the start of measurement of the internal temperature, A step of thawing by intermittently heating while cooling the inside of the thawing chamber until the surface temperature does not exceed the upper limit value and the internal temperature reaches a predetermined thawing temperature, A thawing method characterized by comprising.

5. An end step of stopping the first heating step and the second heating step when the internal temperature reaches a predetermined thawing temperature, The thawing method according to claim 4, characterized by having

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