JPS5935587B2 - Frozen food thawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thawing device that heats and defrosts frozen food such as meat.

Frozen products such as meat are usually frozen at a temperature of -18°C to -20°C and stored in a freezer, and are thawed and used as needed.

Raising the thawing temperature will shorten the thawing time, but generally speaking, if frozen foods are thawed at high temperatures, their original raw state will deteriorate, so they must be thawed at room temperature, usually around 15°C.

Therefore, the conventional method for thawing frozen items is (a) immersing them in water at room temperature.

(b) Place in a stream of water at room temperature.

e→ Leave it naturally in the air at room temperature.

However, since the heat transfer to the inside of the frozen object is based on the heat conduction of the frozen object itself, it takes a long time for the core heat to reach the center and the thawing is completed, and the large size of the frozen object requires a long time. Depending on the situation, it can take anywhere from 8 to 24 hours.

Taking a long time to defrost meat not only causes problems in the process, but also, for example, in the case of frozen meat, the quality of the meat changes and the taste deteriorates, and drips (gravy) are washed away and the taste deteriorates, and the yield also decreases. There is a drawback.

From these viewpoints, it is required that the thawing time of frozen products be short.

As a means of shortening the thawing time, attempts have been made to defrost using high frequency waves, but due to the non-uniformity of the meat quality and shape, it is inevitable that the temperature will be high in some areas and the meat quality will deteriorate in some areas.

An object of the present invention is to provide a thawing device that solves the above-mentioned drawbacks of the conventional thawing method and is capable of thawing the inside of a frozen product at room temperature in a short time.

Hereinafter, the present invention will be explained in detail based on drawings showing embodiments thereof.

The device of the first embodiment of the present invention shown in FIGS.
The substrate 1 has a plurality of solid metal needles 2 installed vertically on its upper surface, and a heater 3 such as a pipe heater is embedded inside the substrate 1.

A temperature-sensitive switch 4 is provided at an appropriate location on the board 1 to detect the temperature of the board 1 and control the energization to the heater 3 so as to always maintain the temperature of the board 1 at a constant optimum thawing temperature. It is designed to be controlled.

It is desirable that the size of this device be suitable for the size of the frozen product; for example, in the case of meat, it is appropriate to make it about the size of a cement bag.

Further, as mentioned above, the appropriate temperature for thawing is about 15°C.

When using the thawing device configured as described above, as shown in FIG.
When the heater 3 is energized and the heat generated is transferred to the surface of the needle by thermal conduction of the metal, the needle 2 is placed on top of the needle 2 which has been heated to the thawing temperature, and when pressed from above, the needle 2 on the underside of the frozen object is heated. The part in contact with the tip is heated and thawed and softened, and the needle 2 gradually penetrates into the frozen object 5. Eventually, the frozen object 5 has its lower surface aligned with the upper surface of the substrate 1, as shown at 5' in the figure. It descends to the position where it touches.

(By doing so, the heat of the substrate 1, which is maintained at a constant temperature of, for example, about 15° C., by the heater 3 and the temperature-sensitive switch 4 is directly transmitted to the lower surface of the frozen object 5 that is in contact with the upper surface of the substrate 1, and The heat is transmitted from the surface to the inside of the frozen object 5 through the prick 2 made of a metal with high thermal conductivity, heating the frozen object to the center much faster than conventional methods and extremely shortening the time until thawing is complete. It is possible to make it shorter.

Therefore, not only the process problems that occurred in the conventional method, but also the deterioration of meat quality, the loss of drips, etc. are solved.

Frozen foods such as meat regain their elasticity once they return to room temperature.
The hole pierced by the needle 2 of this thawing device closes naturally, causing no problem in appearance.

The thawing device is placed only under the frozen product (alternatively, it is also possible to heat the frozen product from both sides by sandwiching it between the top and bottom like a sandwich).

Now, when thawing a frozen object using the above-mentioned thawing device, heat is taken away from the surface of the needle 2 to the frozen object 5, so the temperature T of the surface of the needle 20 is as shown in FIG. It decreases as one goes from the base O to the tip P.

In order to minimize this temperature drop, the cross-sectional area of each part of the needle 2 should be adjusted so that a sufficient amount of heat is transmitted through the needle 2 by conduction compared to the amount of heat transferred from the surface of each part of the needle 2 to the frozen object. It is necessary to make it larger.

However, if the diameter of the pricking needle becomes too large, problems arise in that it becomes difficult to pierce frozen products and the weight of the device increases.

A second embodiment that improves this point will be explained with reference to FIGS. 4 and 5. In this device, the base 11 is formed as a sealed hollow metal container, and a large number of hollow metal needles are provided on the upper surface of the base 11. 12 have been planted.

The space 14 within each needle 12 is closed at its tip and opens at the base into the space 13 within the base 11, and the space 14 within each needle 12 and the space 13 within the base 11 form one space.

At the bottom of the space 13 within the base 11, an electric heater 3 such as a pipe heater is provided.

The sealed spaces 13 and 14 are evacuated and then filled with an appropriate amount of a heat transfer fluid 15 such as water or fluorocarbon.

The sealed space 13 is provided with a sensor for a constant temperature control mechanism 16 that maintains the temperatures of the spaces 13 and 140 constant.

The constant temperature control mechanism 16 includes a bellows 18 that communicates with the space 13 through a thin tube 17, a microswitch 19 that is activated by expansion and contraction of the bellows 18, and a magnet switch 20 that opens and closes the circuit of the heater 30 by connecting or disconnecting this microswitch. It is made up of.

Separately from this control mechanism 16, a temperature-sensitive switch 21, such as a bimetallic type, is provided in parallel, which directly detects the temperature in the space 13 and opens and closes the magnetic switch 20.

Generally speaking, when a fluid is heated under a constant pressure, it always boils at a constant temperature and becomes vapor, and when the vapor loses heat and cools, it returns to a liquid and its volume decreases from a few hundredths to a tenth. It will be a few hundredths.

Further, as a property of saturated steam, there is a certain relationship between its saturated pressure and the temperature of the steam.

Therefore, in this device, when the heat transfer fluid 15 is heated by the heater 3 and boils, and thus the pressure in the spaces 13, 14 increases, the bellows 18 extends, actuating the microswitch 19 and turning off the magnetic switch 20.
Open heater 30 circuit.

Frozen material 5 in contact with the surface of the substrate 11 and the surface of the pricking needle 120
As a result, the amount of heat in the spaces 13 and 14 is taken away via the wall surfaces.

When the vapor of the heat transfer fluid 15 liquefies and its volume decreases, the pressure in the space 13.14 decreases, the bellows 18 contracts, the micro switch 19 is turned off, the magnetic switch 20 is turned on, and the heater 30 circuit is turned on again. When closed, the heat transfer fluid 15 is heated and thus the temperature in the spaces 13, 14 always remains constant.

As mentioned above, a change in temperature immediately results in a change in pressure, which opens and closes the microswitch, allowing for quick response and very good temperature control. The needle 12 turns into a liquid and its volume drastically decreases, and as it flows down the inner surface of the needle 12 as shown by the arrow in the figure, steam is immediately replenished from the base.
The internal temperature of the base plate 2 can be maintained at the same temperature as the inside of the base plate 11 from the base to the tip structure.

Therefore, the diameter of the pricking needle 12 can be selected to be an optimum size from the viewpoint of heat transfer area and strength to the frozen product, and the needle 12 will not be too thick and difficult to pierce.

Now, in the unlikely event that the bellows 18 does not expand or contract properly due to some reason such as leakage from the closed spaces 13, 140,
As the temperature inside 4 rises, the separately provided temperature-sensitive switch 21 is activated, which causes the magnetic switch 20 to activate.
Temperature control is performed by opening and closing.

Normally, the temperature-sensitive switch 21 does not operate and the constant temperature control mechanism 1
To make only 6 actuate, press the temperature sensitive switch 21.
The operating temperature of the constant temperature control mechanism 16 may be slightly higher than that of the constant temperature control mechanism 16.

In this way, the quality of frozen products is prevented from deteriorating due to exposure to excessively high temperatures, and good thawing can be achieved.

Note that it is of course possible to use a temperature-sensitive switch as a constant temperature control mechanism and use a bellows control mechanism for emergency use.

As described above, according to the present invention, it is possible to thaw frozen foods at room temperature within a short period of time, thereby improving process efficiency, quality maintenance,
A remarkable effect on yield improvement can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the first embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a schematic diagram illustrating the surface temperature distribution of the pricking needle, and FIG. 4 is a plan view showing the first embodiment of the present invention. Plan view of the embodiment, fifth
The figure is a longitudinal cross-sectional view. 1.11...Base, 2,12...Prickly needle, meter...Heater, 15...Heating medium fluid,
16... Constant temperature control mechanism.

Claims (1)

[Scope of Claims] 1. A metal base, a large number of metal prickles that are implanted in the base and can pierce frozen objects, a heater built into the base, and gas generated by the heater. A thawing device for frozen products, comprising means for transmitting heat to the surface of the pricking needle, and means for controlling the heater so as to maintain the temperature of the base at a predetermined temperature. 2 The base and the needle are made of solid metal as a means for transmitting the heat generated by the heater to the surface of the needle, and the base is provided with a temperature-sensitive switch as the heater control means. A thawing device according to claim 1. 3. The means for transmitting the heat generated by the heater to the surface of the pricking needle is to form the base as a sealed hollow container, and use the needle as a hollow needle whose tip is closed and whose base is open to the inner space of the base. The means for controlling the heater is constituted by forming and sealing an appropriate amount of heat transfer fluid that boils below the temperature of the substrate to be maintained during thawing in the integrated space under vacuum. Claim 1, characterized in that it is constituted by means for detecting the temperature and pressure of the heat medium fluid in the space within the base, and a constant temperature control mechanism for controlling the heater based on the detection signal. thawing device.