JP2801012B2 - Decompression device and decompression method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thawing apparatus and a thawing method using a mixed fluid of air and steam for thawing frozen foods and the like.

2. Description of the Related Art Conventionally, as a thawing device of this type, a circulating passage with a circulating fan device for circulating air in a thawing chamber is provided, and a steam supply pipe is connected to the circulating passage on the discharge section side of the circulating fan device. In addition, there is known a device configured to appropriately mix steam with circulating air.

Problems to be Solved by the Invention The thawing apparatus having the above configuration has the advantage that the thawing time is short and that the thawed food does not dry, but on the other hand, the mixing of steam and air and heat exchange are not completely performed, resulting in uneven temperature. When air containing supersaturated steam having a high temperature passes through the thawing chamber, especially at the final stage of thawing, when the surface temperature of the thawed food is above the freezing point, uneven thawing on the food surface or condensation of steam is generated. This dissolves the water-soluble substances in the food, increasing the amount of drip. For this reason, there has been a problem that foods that do not take measures such as reducing the drip by wrapping the foods with a film have been regarded as inappropriate.

Means for Solving the Problems The present inventor investigated the causes of the above-mentioned problems, that is, the reason why the mixing of steam and air and the heat exchange became incomplete, and as a result, the steam supply pipe was located at the discharge section side of the circulation fan device. And the distance from the time when the steam is mixed with the air to the time when the steam reaches the thawing chamber, that is, the length of the heat exchange passage for the steam and the air is insufficient, but the stirring function of the circulation fan device is not fully utilized. , Temperature and humidity unevenness in the air-steam mixture,
Alternatively, the fact that the control of the steam amount was not properly performed was confirmed.

Therefore, in the thawing apparatus of the present invention, the heat exchange passage between steam and air is set long in the circulation passage having a fixed length, and the heat exchange is sufficiently performed by mixing steam and air at a uniform temperature and humidity. A circulating passage with a circulating fan device for circulating the air in the thawing chamber and a steam supply pipe for supplying steam into the circulating passage.
The steam supply pipe is connected to the circulation passage on the upstream side of a U-shaped suction passage portion from the thawing chamber to the circulation fan device with respect to the circulation passage. When thawing the object using the above-mentioned thawing device, the air temperature at the ventilation port and the surface temperature of the object are detected, and the steam supply amount is adjusted based on the detected temperatures to adjust the amount of steam supply. Is characterized in that the air temperature is kept substantially constant.

In the above configuration, the air in the thawing chamber is circulated through the circulation passage by driving the circulation fan device, and mixes with the steam from the steam supply pipe. In this case, the steam supply pipe is connected to the circulation passage at the suction passage from the thawing chamber to the circulating fan device. Is longer than in the case. Further, since the steam from the steam supply pipe passes through the circulation fan device together with the air, the stirring function of the circulation fan device works sufficiently, and the steam and the air are mixed at a uniform temperature and humidity. When thawing the thawing material using this thawing device, the temperature of the thawing material is detected, the amount of steam supplied is adjusted, and the air temperature in the thawing room is kept almost constant.
Maintained at 100%, there is no uneven thawing, and excessive humidification and drying of the surface of the object to be thawed are prevented.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic vertical sectional side view of a defrosting apparatus according to one embodiment of the present invention. In FIG. 1, 1 is a thawing room,
A plurality of shelves 3 on which the objects to be defrosted (foods) 2 are placed are arranged therein, and a pair of opposed side walls of the defrosting chamber 1 are provided.
A large number of ventilation holes 6 and 7 are formed in 4 and 5, respectively.
Reference numeral 8 denotes a circulation passage, one end of which is connected to the thawing chamber 1 by the vent 6 and the other end of which is connected to the thawing chamber 1 by the vent 7. Reference numeral 9 denotes a circulating fan device. The circulating fan device 9 is disposed almost in the middle of the circulating passage 8 so that a discharge passage portion 8a from the circulating fan device 9 to the thawing chamber 1 is provided.
And a suction passage 8b from the thawing chamber 1 to the circulation fan device 9
Is formed, and a portion of the suction passage portion 8b facing the thawing chamber 1 is bent into a U-shape by a baffle plate 10 and is elongated. Reference numeral 11 denotes a steam supply pipe, which extends from the steam generator 12 and has a front end 11a with respect to the circulation passage 8.
It is connected on the upstream side of the suction passage 8b. Reference numeral 13 denotes a refrigerator, and its cooling pipe 13a is disposed on the suction side of the circulation fan device 9. Reference numeral 14 denotes a control panel, which is a steam generator based on a temperature sensor 15 for detecting the surface temperature of the material 2 to be thawed and a temperature sensor 16 for detecting the air temperature at the vent 7.
12, for controlling the circulation fan device 9, the refrigerator 13, and the like. A drain pipe 17 is provided at the bottom of the thawing chamber 1 and the suction passage 8b.

Next, the operation of the above configuration will be described. To defrost the object 2 to be thawed, the circulation fan device 9 is driven. As a result, the air in the thawing chamber 1 is drawn from the suction passage 8b to the circulation fan device 9, and flows through the discharge passage 8a to the thawing chamber 1 again. That is, the air in the thawing chamber 1 is circulated through the circulation passage 8 by the circulation fan device 9. On the other hand, with respect to the flow of air, steam is supplied from the steam supply pipe 11 into the circulation passage 8, and the mixture of air and steam passes through the thawing chamber 1, so that the object 2 to be thawed is thawed. .

Here, the distal end 11 a of the steam supply pipe 11 is connected to the circulation passage 8 by a suction passage from the thawing chamber 1 to the circulation fan device 9.
8b, the suction passage portion 8b is bent into a U-shape, and the front end portion 11a is connected upstream thereof, so that the front end portion 11a is connected to the discharge passage portion 8 of the circulation fan device 9.
Compared with the conventional configuration connected on the a side, in the case of the present embodiment, the distance from when the steam is mixed with the air to when the steam reaches the thawing chamber 1,
That is, the length of the steam-air heat exchange passage is long enough to correspond to substantially the entire length of the circulation passage 8. That is, in summary, in the case of the present embodiment, the length of the heat exchange passage for steam and air is
It can be set longer than before.

In the case of the present embodiment, the steam from the steam supply pipe 11
Since the gas passes through the circulation fan device 9 together with the air, the stirring operation of the circulation fan device 9 works sufficiently, and the steam and the air are mixed at a uniform temperature and humidity.

After all, according to the present embodiment, as described above, the heat exchange passage between steam and air becomes longer, the heat exchange passage between steam and air becomes longer, and the mixture of steam and air has a uniform temperature and humidity. As a result, heat exchange between the two is sufficiently performed, and uneven thawing and drip on the surface of the object 2 are prevented.

Further, in the above configuration, the heat exchange passage between steam and air is elongated, and the suction passage portion 8b is bent in a U-shape, so that the condensed water is efficiently drained. Excessive humidification and drip of the surface of the object 2 are prevented as much as possible.

Next, a method of controlling the supplied steam amount will be described. First, the temperature sensor 15 detects the surface temperature of the material 2 to be defrosted, while the temperature sensor 16 detects the temperature of air blown into the defrosting chamber 1 from the circulation fan device 9. The control panel 14 calculates the total amount of steam required for heating and humidifying the air based on the detection results of the temperature sensors 15 and 16, and supplies steam from the steam generator 12 to the steam supply pipe 11. The amount is set.

Here, when the amount of steam supplied from the steam supply pipe 11 to the circulation passage 8 is larger than the amount of heat required for thawing the object 2 to be thawed, the amount of steam is reduced to a value corresponding to the air temperature. That is, the air temperature is a certain temperature, for example, a low temperature of 15 ° C., and if the air contains supersaturated steam, the air temperature increases,
Control for reducing the amount of supplied steam works to obtain air free of supersaturated steam with a relative humidity of steam and air (hereinafter referred to as RH) of almost 100%.

When the supplied steam amount is smaller than the required heat amount for thawing, the supplied steam amount is increased so that the air temperature becomes constant. In this case, the air temperature after heating is lower than the required value, and the thawing time is slightly longer. However, if the amount of steam is controlled based on the air temperature, the RH of the air is maintained at almost 100%. The resulting defrost (food) is not dried.

Further, according to the present apparatus, the temperature control of the object to be thawed 2 is performed as follows.

First, based on the surface temperature of the thawing object 2 detected by the temperature sensor 15, in the final step of raising the thawing temperature, the control panel 14 is controlled so that the maximum value of the surface temperature of the thawing object 2 remains in the ice temperature region. Refrigerator 13 is operated and controlled through. That is, when the surface temperature of the object 2 is higher than 0 ° C., the condensed water generated by air cooling adheres to the surface of the object 2 and causes excessive humidification or drip. If the surface temperature is lower than 0 ° C, it will cause insufficient thawing. In order to prevent the occurrence of these causes and to minimize the amount of drip, control to keep the surface temperature of the food in the ice temperature region as described above is performed. Done.

Effect of the Invention As described above, according to the thawing apparatus and the thawing method of the present invention, the steam supply pipe passes through the circulation passage, and is located upstream of the U-shaped suction passage from the thawing chamber to the circulation fan device. Because of the connection, in the circulation path of a certain length, the heat exchange path of steam and air is set to be long, and the stirring function of the circulation fan device works sufficiently, so that the steam and air mix at a uniform temperature and humidity, Heat is sufficiently exchanged to prevent uneven thawing, and by appropriately controlling the amount of steam supplied based on the air temperature at the ventilation port and the surface temperature of the object to be thawed, the excess of the surface of the object to be thawed is obtained. There is an effect that humidification and drying can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional side view of a defrosting apparatus according to one embodiment of the present invention. 1 ... Thawing room, 2 ... Thawed object, 8 ... Circulation passage, 8b ...
... Suction passage, 9 ... Circulation fan device, 11 ... Steam supply pipe.

Continued on the front page (72) Inventor Masao Arita 1-6-14 Edobori, Nishi-ku, Osaka-shi, Osaka Inside the Shipbuilding & Engineering Center, Hitachi Zosen Corporation (72) Inventor Tokukuni Kafuku 1-6-14, Edobori, Nishi-ku, Osaka-shi, Osaka Inside Hitachi Shipbuilding & Shipbuilding Co., Ltd. (72) Inventor Tetsuro Miyake 3-4-1-116 Chikko, Minato-ku, Osaka-shi, Osaka In-house Water Treatment Research Institute (72) Inventor Toru Matsuno 3, Imabashi, Higashi-ku, Osaka-shi, Osaka ―30 Nissho Iwai Equipment Sales Co., Ltd. (72) Inventor Hisatoshi Shimase 3-30 Nissho Iwai Equipment Sales Co., Ltd. (72) Inventor Kazuo Minoki Imabashi, Higashi-ku, Osaka, Osaka 3-30 Nissho Iwai Equipment Sales Co., Ltd. (56) References JP-A-54-154543 (JP, A) JP-A-59-130496 (JP, U) (58) Fields investigated (Int. Cl. ⁶⁾ A23L 3/36-3/54 F25D 23/00-23/12

Claims (2)

(57) [Claims] 1. A thawing apparatus comprising: a circulating passage having a circulating fan device for circulating air in a thawing chamber; and a steam supply pipe for supplying steam into the circulating passage, wherein the steam supply pipe faces the circulating passage. A thawing device, wherein the thawing device is connected to an upstream side of a suction passage formed in a U-shape from the thawing chamber to the circulation fan device. 2. A circulation path with a circulation fan device for circulating air in a thawing chamber, and a steam supply pipe for supplying steam into the circulation path, wherein the steam supply pipe is connected to the circulation path with respect to the circulation path. When thawing an object to be thawed using a thawing device connected upstream of a suction passage formed in a U-shape from the thawing chamber to the circulation fan device, the air temperature at the ventilation port and the surface of the object to be thawed A thawing method characterized by detecting temperatures and adjusting a steam supply amount based on both of the detected temperatures to keep an air temperature in the thawing chamber substantially constant.