JPH03219858A - Thawing device - Google Patents

Abstract

PURPOSE:To uniformly thaw a material to be thawed and to prevent unevenness of thawing by horizontally and opposingly installing normally and reversibly rotatable multiblade fans at both left and right edge parts of thawing chamber and changing patterns of stream flow at proper intervals with time. CONSTITUTION:Materials A to be thawed are placed in space between shelves of cages 9 and the cages are stored in a thawing chamber 1 by a truck 8. Then, a warm water feed part 10 is operated, water at a given temperature is circularly fed to a water tank 2 at the bottom of the thawing chamber 1 to generate steam. Then circulating fans 4 and 4' uprightly set at supporting frames 6 and 6' at both left and right edges of the thawing chamber 1 are started, air containing steam evolving from the water tank is sent from the left end to the right end, steam is condensed on the low temperature surface of the materials A to be thawed and the materials A to be thawed are thawed by condensation heat. After a fixed time, the rotary direction of the fans 4 and 4' is reversed, the steam is sent from the right end to the left end to thaw the materials.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thawing device, and more particularly to a steam condensing thawing device suitable for thawing a large amount of frozen products.

[Prior art]

With the liberalization of food imports from overseas, large quantities of fresh food are frozen and imported, which are thawed according to demand and used as raw materials for processed foods, or supplied to consumers using the distribution system. The time has come to do so. Therefore, there is an urgent need to develop a large-capacity thawing device that can thaw large quantities of frozen products without losing flavor or freshness.

Conventionally, several methods such as water thawing method and high frequency thawing method have been proposed and implemented as a thawing device for frozen products.
A steam condensing type thawing device exemplified in No. 229 can be mentioned. In this thawing device, a shallow hot water tank is provided at the bottom of the thawing chamber, and a heating device is used to maintain the temperature at a predetermined temperature (for example, 10
Warm water heated to a temperature of around 30°F (°C) is supplied and circulated to this tank, generating relatively low-temperature water vapor. In the thawing chamber, the water vapor rising from the water tank at the bottom condenses on the surface of the items to be thawed placed on the shelf installed at the top of the thawing chamber due to its low temperature, forming dew or frost. At this time, a considerable amount of condensation heat is generated, and the product to be thawed is thawed by this heat. As thawing progresses, the temperature of the thawed product also rises, so this is detected with a thermometer, and when the temperature reaches a predetermined temperature, the hot water supply is stopped and the refrigerator attached to the thawing device is activated to refrigerate the thawed product. It retains its freshness.

[Problem to be solved by the invention]

In the above-mentioned conventional steam condensing thawing equipment, the heat transfer coefficient is high because the basis of heat transfer is condensation of steam.
Although it has the advantage of being simpler to install than other types of decompressing devices, there are the following problems that must be solved when this is used as a large capacity decompressing device. In other words, the rise of air containing water vapor depends on natural convection, so if the thawing chamber becomes large, the flow distribution of water vapor in the room will not be uniform, and as a result, the areas that are often hit by water vapor will be too thawed and the temperature will rise. While the rise is large and even drips are seen, areas with poor water vapor flow are insufficiently thawed and remain frozen. An object of the present invention is to provide a new thawing device that solves the problem of uneven thawing of the water vapor condensation type large-capacity thawing device described above.

[Means for Solving the Problems] The gist of the present invention is to supply hot water at a predetermined temperature to a water tank at the bottom of a thawing chamber, and to collect water vapor generated from the hot water into a cover placed at the top of the thawing chamber. In a thawing device that condenses on the surface of thawed products and thaws them using the heat of condensation, multi-blade fans that can rotate forward and backward are installed facing each other on support frames erected at both left and right ends of the thawing chamber. This is a unique thawing device.

[For production]

Multi-blade fans that can rotate forward and backward are installed horizontally at both the left and right ends of the thawing chamber, and the flow pattern of air containing water vapor inside the thawing chamber is changed at appropriate intervals to thaw products uniformly. This has the effect of preventing uneven thawing.

〔Example〕

The contents of the present invention will be further explained below based on drawings showing examples. FIG. 1 is a plan view of a thawing device embodying the present invention, and FIG. 2 is an elevational view showing a partially reduced section. In the figure, reference numeral 1 denotes a thawing chamber made of walls made of heat insulating material, etc. A shallow water tank 2 is provided at the bottom, and a refrigerant coil 3 for indoor cooling is suspended from the ceiling. Hot water at a predetermined temperature is supplied and circulated to the water tank 2 through a pipe (not shown), which is regulated by a hot water supply unit 1O, which is provided adjacent to the thawing chamber and includes an electric heater, a tank, a pump, and the like. A refrigerant at a predetermined temperature adjusted by a refrigerant supply section 20 comprising a compressor, a heat exchanger, etc. is supplied and circulated to the refrigerant coil 3 through a pipe line (not shown). 4,4゛ is a circulation fan consisting of multi-blade blades that can rotate forward and backward, and pillars 5,5° are installed at the four corners of the thawing chamber.
A rotating shaft is horizontally attached to the support frames 6, 6' which are erected using the support frames 6, 6'. The left and right circulation fans 4, 4' are provided in multiple stages facing each other as shown in FIG. 7
is an opening/closing door for loading and unloading the cart 8 loaded with items to be thawed. The cart 8 is equipped with a cage 9 in which items to be thawed can be loaded in multiple stages using shelves, and the height of the shelves can be adjusted so that air containing water vapor can freely pass through each transom. 30 is a control unit, which controls the temperature in various parts of the thawing chamber;
It houses various controllers necessary for controlling the switching time of the circulation fan between forward and reverse rotation.

A method of operating the thawing device having the above configuration will be explained next. In cage 9, for example, thawed product A frozen at -30°C
are loaded with space between each shelf and housed in the thawing chamber using the trolley 8 and its rails.

The hot water supply unit 10 is operated to supply and circulate hot water maintained at, for example, 10° C. to the water tank 2 to generate water vapor in the thawing chamber. Next, the circulation fans 4.4' are activated and the rotation directions of the circulation fans 4, 4' are set so that the flow pattern of the air containing water vapor in the thawing chamber flows from the left end to the right end as shown in FIG. The water vapor generated from the water tank 2 is inside the cage 9.
It flows between the items to be thawed A according to this flow pattern, condenses on the low temperature surface of the items to be thawed, and thawing proceeds with the heat of condensation at this time. However, if the same pattern flows in one direction, the flow distribution of water vapor will inevitably be biased, so for example, 3
After about 0 minutes, as shown in Figure 4, turn on the circulation fan 4,
4. Reverse the direction of rotation to change the flow direction of water vapor from the right end to the left end. These changes are automatically made by a sequence circuit including a timer. By performing the above pattern switching alternately during the thawing operation, the product to be thawed can be thawed uniformly and uneven thawing can be prevented from occurring. The flow patterns in the thawing chamber are not limited to those shown in Figures 3 and 4, and may vary depending on the shape of the product to be thawed,
It is desirable to adopt a suitable pattern depending on the properties. At this time, the multi-blade fan is installed in multiple stages in the vertical direction, so
The flow pattern must be determined so that water vapor flows uniformly not only on the horizontal plane but also on the upper and lower planes. Furthermore, if the motor of the multi-blade fan is of a variable speed type and the air volume is adjusted, it is possible to defrost food even more ideally.

〔effect〕

According to the present invention having the configuration and operation described above, by appropriately changing the flow pattern of water vapor in the thawing chamber over time according to the shape and properties of the thawed product, thawing can be performed uniformly and uneven thawing can be prevented. It is possible to uniformly thaw a large amount of frozen products and obtain high-quality thawed products.

[Brief explanation of drawings]

FIG. 1 is a plan view of a thawing apparatus embodying the present invention, FIG. 2 is an elevational view showing a partial longitudinal section, and FIGS. 3 and 4 are drawings showing flow patterns in the thawing chamber. 1; Defrosting chamber, 2; Water tank, ; Circulation fan, 5.5"7; Door, 8; Cart, supply section, 20; Refrigerant supply section, 3; Refrigerant coil, 4.4'; Pillar, 6.6 ', support frame, 9; cage, lO; hot water supply 30; control unit.

Claims (1)

[Claims] Thawing involves supplying hot water at a predetermined temperature to a water tank at the bottom of the thawing chamber, causing the water vapor generated from the hot water to condense on the surface of the thawed product placed at the top of the thawing chamber, and thawing the product using the heat of condensation. A thawing device characterized in that multi-blade fans capable of forward and reverse rotation are installed facing each other on support frames erected at both left and right ends of a thawing chamber.