JPH09154554A - Food freezing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food freezing unit high in the heat exchange efficiency between an object to be frozen and cold source gas and capable of improving the utility of the cold source gas. SOLUTION: This food freezing unit lies equipped with a tunnel 21 having loading port 28 and an unloading port 36 on both ends, respectively, a belt conveyor 22 set up inside the tunnel 21 along the longer direction extending from the loading port 28 toward the unloading port 36 to convey objects to be frozen, a low-temperature liquefied gas feed mechanism 43 to feed low- temperature liquefied gas into the tunnel 21, and an exhaust mechanism 44 to discharge the gas in the tunnel 21. A gas flow meandering control mechanism 48 is provided to allow the gas in the tunnel 21 to flow under meandering in the longer direction, and plural shelves are equipped on the belt conveyor 22 to put objects to be frozen thereon, and food carrying racks 31 are put on the shelves so as to allow air to flow in the gas stream flow direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food freezing device used for producing frozen foods, and more particularly to a technique for improving the utilization efficiency of low temperature liquefied gas used as a cold heat source.

[0002]

2. Description of the Related Art Conventionally, as an apparatus suitable for producing frozen foods, there is one shown in FIG. 12, for example. The food freezing device 50 is roughly configured by a tunnel portion 1, a belt conveyor 2, a low temperature liquefied gas supply mechanism 13, and an exhaust mechanism 14. The tunnel part 1 is formed in a tunnel shape having a carry-in port 9 and a carry-out port 10 at both ends, and a plurality of stirring fans 3 for stirring the gas in the tunnel part 1 are attached to the upper part of the inner surface thereof. A belt conveyor 2 extending from the carry-in port 9 to the carry-out port 10 is provided in the tunnel portion 1. A low temperature liquefied gas supply mechanism 13 for supplying a low temperature liquefied gas such as liquefied nitrogen or liquefied carbon dioxide is provided near the carry-out port 10 above the tunnel portion 1. The low temperature liquefied gas supply mechanism 13 supplies a low temperature liquefied gas used as a cold heat source to the low temperature liquefied gas supply pipe 33.
And a control valve 4 for controlling the supply amount thereof, and a spray nozzle 5 for ejecting the supplied low temperature liquefied gas into the tunnel portion 1.
And Further, in the vicinity of the carry-in port 9 of the tunnel portion 1, an exhaust mechanism 14 for discharging the gas in the tunnel portion 1 is provided. The exhaust mechanism 14 includes a tubular exhaust duct 8 that guides the gas in the tunnel portion 1 and an exhaust fan 12 that is provided in the exhaust duct 8 and forcibly exhausts the gas.

In order to freeze food by using such a conventional food freezing device 50, the food to be frozen is placed on the belt conveyor 2 in the vicinity of the carry-in port 9, and the conveyor driving device 7 carries the belt conveyor 2 out. The food is introduced into the tunnel portion 1 by driving in the direction. The food introduced into the tunnel portion 1 is conveyed in the outlet direction according to the driving of the belt conveyor 2. As described above, the food conveyed in the tunnel portion 1 comes into contact with the low temperature liquefied gas supplied from the spray nozzle 5 and freezes when reaching the vicinity of the low temperature liquefied gas supply mechanism 13 in the conveying process. The frozen food is carried out from the carry-out port 10 according to the driving of the belt conveyor. The low temperature liquefied gas introduced into the tunnel portion 1 vaporizes while freezing the food. This vaporized gas is hereinafter referred to as cold heat source gas.

[0004]

In such a conventional apparatus, since the heat exchange efficiency between the object to be frozen and the cold heat source gas is low, foods or packages such as fried foods and grilled foods having a high temperature before freezing are packaged. When freezing foods and the like, there were cases where freezing became defective. To avoid this, tunnel section 1
It was necessary to increase the length of the product, increase the width of the product in order to secure the production amount, reduce the driving speed of the belt conveyor, and increase the residence time of the frozen material in the tunnel portion. However, when the length or width of the tunnel portion 1 is increased, the installation area of the device is increased, which is disadvantageous from the viewpoint of space saving. Further, when the driving speed of the belt conveyor is lowered, the processing speed becomes low, and there is a problem that productivity is lowered. Moreover, since the carry-in port 9 and the carry-out port 10 of the tunnel portion 1 are of an open type, there is a problem that the cold heat source gas easily escapes from the carry-in port 9 or the carry-out port 10, and the utilization efficiency of the cold heat source gas is poor. Was.

The present invention has been made in view of the above circumstances, and provides a food freezing device which has a high heat exchange efficiency between an object to be frozen and a cold heat source gas and which can improve the utilization efficiency of the cold heat source gas. With the goal.

[0006]

In the food freezing apparatus of the present invention, a tunnel portion having a carry-in port and a carry-out port at both ends, and the inside of the tunnel part are arranged along the longitudinal direction extending from the carry-in port to the carry-out port. , A belt conveyer for transporting the frozen material, a low temperature liquefied gas supply mechanism for supplying a low temperature liquefied gas into the tunnel portion, and a tunnel inlet portion which is provided on the carry-in side of the low temperature liquefied gas supply mechanism for the tunnel portion. With an exhaust mechanism for discharging, inside the tunnel portion, a gas flow meandering adjusting mechanism that causes the gas in the tunnel portion to meander in the longitudinal direction is provided, and on the belt conveyor,
It is characterized in that it comprises a plurality of shelves on which frozen objects are placed and a food transport rack on which a gas flow direction can be ventilated.

The gas flow meandering adjusting mechanism is composed of a plurality of agitating fans for flowing gas in a lateral direction traversing the longitudinal direction of the tunnel portion, and a plurality of rectifying plates for interrupting the flow of gas toward the carry-out port. The agitating fans are provided on both side walls of the tunnel portion at intervals in the longitudinal direction, and the relative positions between the two sides are displaced, and the straightening vanes are provided on the carrying-in direction side of the agitating fan. The tip may be provided in the vicinity of the food transport rack transported on the belt conveyor.

Further, inside the tunnel portion, there is provided a ventilation plate having a ventilation hole that allows a part of the gas in a predetermined compartment in the tunnel portion to flow toward the carry-in port and circulates the remaining portion in the predetermined compartment. The ventilation plate may be provided on the discharge port side of the stirring fan, and the tip of the ventilation plate may be provided in the vicinity of the food transport rack transported on the belt conveyor. Further, the ventilation plate may have a configuration in which the opening degree of the ventilation hole can be adjusted. Further, a carry-in door and a carry-out door may be opened and closed at the carry-in entrance and the carry-out exit of the tunnel portion, respectively.

[0009]

1 to 6 show an embodiment of a food freezing apparatus according to the present invention, in which reference numeral 20 indicates a food freezing apparatus. The food freezing device 20 is roughly configured by a tunnel portion 21, a belt conveyor 22, a low temperature liquefied gas supply mechanism 43, and an exhaust mechanism 44.

The tunnel portion 21 is formed in a tunnel shape having a carry-in port 28 and a carry-out port 36 at both ends. The carry-in port 28 and the carry-out port 36 are provided with a carry-in door 28A and a carry-out door 36A, respectively. Has been.

As shown in FIG. 4 (A), the carry-in door 28A has first and second doors 28B and 28C, and is mounted with the carry-in entrance 28 closed. The first and second doors 28B and 28C are slidably provided at the arrow (c) and the arrow (d), respectively, so that the carry-in port 28 can be opened as shown in FIG. 4 (B). Has become. The carry-out door 36A (not shown) is the carry-in door 28A.
Similarly, the first and second doors 36 </ b> B and 36 </ b> C are provided, and the opening and closing is provided at the carry-out port 36. The carry-in door 28A and the carry-out door 36A are normally closed.

A belt conveyor 22 is provided in the tunnel portion 21 from a carry-in port 28 to a carry-out port 36. The belt conveyor 22 is driven by a driving means such as a motor, and its driving speed can be adjusted.
By driving the belt conveyor 22, the frozen object placed on the upper surface of the belt conveyor 22 is conveyed from the carry-in port 28 to the carry-out port 36 in the tunnel portion 21. The belt conveyor 22 is provided slightly longer than the tunnel portion 21, so that the introduction portion 22A is provided in front of the tunnel portion 21.
However, the lead-out portion 22B is provided after the tunnel portion 21.

A food transport rack 31 as shown in FIG. 3 is placed on the belt conveyor 22.
The food transportation rack 31 is a box-shaped body whose left and right are open, and the material thereof is a non-breathable material such as wood, synthetic resin, or metal. Reference numerals 31A and 31A in the drawing show openings of the food transport rack 31. Also food transport rack 3
Inside 1 is a plurality of shelves 31C for placing food items.
Are formed, and these shelves 31C are formed of a wire mesh that is permeable to air. The number of the shelves 31C provided on one food transport rack 31 is 3 to 15.

As shown in FIG. 1, the food transport rack 31 is arranged in two rows and placed on the belt conveyor 22. At this time, the food transport rack 31 has openings 31A and 3A.
1A is arranged so as to face the lateral direction of the tunnel portion. The transportation method of the food transportation rack 31 is not limited to this, and may be one row or three or more rows.

Further, inside the both side walls of the tunnel portion 21,
A plurality of agitating fans 23 are provided at intervals in the longitudinal direction for the two food transport racks, and the relative positions between the two sides are displaced. Also, this stirring fan 23
Is a food transport rack 3 that is transported on the belt conveyor 22.
It is provided close to the first opening 31A.

Further, as shown in FIG. 1 and FIG. 6, the carry-in port 2 of the stirring fan 23 is provided on the inner side of both side walls of the tunnel portion 21.
A current plate 32 is provided on the eight direction side. This current plate 3
Reference numeral 2 is for obstructing the flow of gas in the tunnel portion 21 in the direction of the discharge port 36, and is an elongated plate-like member formed of a non-breathable material such as synthetic resin or metal. It is formed to project in the hand direction. Further, this straightening plate 32 is a food transport rack 31 that is transported on the belt conveyor 22.
Is provided so that the tip is close to. The plurality of agitating fans 23 and the straightening vanes 32 form a gas flow meandering adjusting mechanism 48 which causes the gas in the tunnel portion 21 to meander in the longitudinal direction of the tunnel portion and flows.

Further, the carrying port 36 of the stirring fan 23 is slightly
A ventilation plate 35 is provided on the direction side. This ventilation plate 3
5 is formed in an elongated plate shape, and is formed so as to project in the lateral direction of the tunnel portion 21. Further, the ventilation plate 35 is provided such that the tip thereof is close to the food transportation rack 31 transported on the belt conveyor 22. Further, as shown in FIG. 8, a plurality of ventilation holes 37 are provided in the ventilation plate 35, and gas can flow in and out through the ventilation holes 37. The ventilation plate 35 is made of synthetic resin or metal. The plurality of ventilation plates 35 are for flowing a part of the gas in the tunnel portion in the direction of the carry-in port and circulating the remaining portion in a predetermined section in the tunnel portion 21.

The width of the current plate 32 and the ventilation plate 35, that is, the width a shown in FIG. 1 is 10 to 15 cm. If this width is less than 10 cm, the effect of blocking the gas flow becomes insufficient. Further, if the width exceeds 15 cm, the width through which the food transport rack 31 in the tunnel portion 21 can pass becomes small, which is not preferable.

Further, a plurality of low temperature liquefied gas supply mechanisms 43 are provided on the upper surface of the tunnel portion 21 close to the stirring fan 23. This low temperature liquefied gas supply mechanism 43
Are provided in the vicinity of the two or more stirring fans 23 from the one close to the carry-out port 36 among the stirring fans 23,
As shown in FIGS. 2 and 5, a gas supply pipe 33 for supplying a low temperature liquefied gas such as liquefied nitrogen or liquefied carbon dioxide gas from a supply source (not shown), and a control valve 24 for adjusting the supply amount thereof.
A spray nozzle 25 for injecting a low-temperature liquefied gas into the tunnel portion 21, a temperature sensor 27 for measuring the temperature inside the tunnel portion 21, and a temperature controller 26 for controlling opening / closing of the control valve 24 in cooperation with the temperature sensor 27. It consists of and.

In the low temperature liquefied gas supply mechanism 43, the temperature inside the tunnel portion 21 is measured by the temperature sensor 27, and the control valve 24 is opened / closed by the temperature controller 26 according to the measured temperature, so that the temperature inside the tunnel portion 21 is increased. The low temperature liquefied gas is introduced into the tunnel portion 21 so that the temperature becomes a preset range. The set temperature can be arbitrarily set by the temperature controller 26.

An exhaust mechanism 44 is provided near the carry-in port 28 of the tunnel portion 21. This exhaust mechanism 44
Is composed of a tubular exhaust duct 29 that guides the gas in the tunnel portion 21, a damper 34 that is provided in the exhaust duct 29 to adjust the exhaust amount, and an exhaust fan 30 that is provided in the exhaust duct 29. There is. This exhaust mechanism 44
In the tunnel portion 2 by driving the exhaust fan 30.
The gas in 1 is forcibly discharged. Further, the frequency of the exhaust fan 30 is convertible, and the rotational speed of the exhaust fan 30 is changed by this frequency conversion to adjust the exhaust amount.

The production of frozen food using the food freezing device 20 is performed as follows. The food to be frozen is placed on the shelf portion 31C of the food transport rack 31, and further, the food transport rack 31 is introduced into the introduction portion 22A of the belt conveyor 22 with both openings 31A and 31A of the food transport rack 31 oriented in the lateral direction of the tunnel portion 21. After placing the two in parallel with each other, the belt conveyor 22 is driven in the direction of the arrow (b) to introduce the two food transport racks 31 from the carry-in port 28 into the tunnel portion 21.

At this time, the carry-in door 28A of the carry-in entrance 28 is
When the food transport rack 31 is introduced into the tunnel portion 21, the food transport rack 31 is opened and the food transport rack 31 is opened.
After entering, it is closed again. Food transport rack 3
Belt conveyor 2 when 1 enters tunnel 21
2 will stop for a while. After a certain period of time in this state,
The belt conveyor 22 is further driven in the direction of the carry-out port to newly introduce two food transport racks 31 into the tunnel portion 21 and again stopped for a certain period of time.

In this way, the operation of intermittently driving the belt conveyor 22 to introduce two food transport racks 31 into the tunnel portion 21 is repeated, and the food transport racks 31 thus introduced are installed in the tunnel portion 21. Arrow (b)
Move in the direction.

In the low temperature liquefied gas supply mechanism 43, the low temperature liquefied gas supplied from a supply source (not shown) is
It is ejected from the spray nozzle 25 into the tunnel portion 21. The low-temperature liquefied gas 40 injected by the spray nozzle 25 is vaporized and becomes a cold heat source gas, and as shown in FIG. 5, is sent in the direction of the arrow (d) by the stirring fan 23 and passes through the opening 31A to form two foods. It passes through the transport rack 31. At this time, since the side plate and the upper plate of the food transport rack 31 block the flow of the gas in the longitudinal direction of the tunnel portion and the vertical direction, almost all of the gas goes straight in the direction of arrow (d). In the above process, the gas cools the food on the food transport rack 31.

The gas having passed through the food transport rack 31 eventually reaches the side wall 21A of the tunnel portion 21 and its flow direction changes. At this time, most of the gas is rectifying plate 3
2 and the ventilation plate 35, the current does not flow in the longitudinal direction of the tunnel portion 21, but flows upward and downward.

Of the above-described gas that has flowed in the vertical direction, the gas that has flowed in the upward direction hits the upper wall of the tunnel portion 21 and flows in the direction of the arrow (c), reaches the side wall 21B of the tunnel portion 21, flows downward, and is stirred. After reaching the fan 23, it is sent again in the direction of arrow (d) by the stirring fan 23.

On the other hand, the gas which hits the side wall 21A and flows downward flows through the belt conveyor 22 in the direction of arrow (c), hits the side wall 21B and flows upward, and again by the stirring fan 23 the arrow (d). Sent in the direction. In this way, the above-described gas makes a circular motion in a predetermined section of the tunnel portion 21 in a substantially 8-shape. This circulation motion increases the flow velocity of the gas, and promotes heat exchange between the gas and the food placed on the food transport rack 31.

Here, the vicinity of the carry-in port 28 in the tunnel portion 21 is slightly negative pressure due to the forced exhaust by the exhaust mechanism 44 provided near the carry-in port 28 of the tunnel portion 21. Therefore, as shown in FIG. 7, the low-temperature liquefied gas 40A supplied from the spray nozzle (not shown) of the low-temperature liquefied-gas supply mechanism 43A into the tunnel portion 21 is partially moved by the arrow ( (A) is sucked in the direction, passes through the ventilation hole 37 of the ventilation plate 35A, and moves to the next stage.

The above-mentioned gas reaching the next stage is stirred by the stirring fan 2.
3B carries out the above-mentioned circulatory motion, part of which is the side wall 21.
After passing through the ventilation hole of the ventilation plate 35B of A, it further moves to the next stage, and the above-mentioned circulation movement is performed by the stirring fan 23C.

By repeating the above process, the gas moves in the direction of the carry-in port 28 while meandering in the tunnel portion 21 in a zigzag shape, and when it reaches the vicinity of the exhaust mechanism 44, the gas is forced out of the system by the exhaust mechanism 44. Is discharged. Further, since the flow straightening plate 32 is provided on the side wall of the tunnel portion 21 as described above, an efficient meandering motion is performed without the gas flowing backward in the arrow (b) direction in the above process. Since the gas meanders in a zigzag manner in the longitudinal direction of the tunnel portion 21, the gas flow path is long and the flow velocity is high.
Heat exchange with unfrozen food is promoted.

As described above, the food placed on the food transport rack 31 is heat-exchanged with the low temperature liquefied gas and is frozen in the tunnel portion 21. The food transport rack 31 on which the frozen food is placed further moves in the direction of the arrow (B) with the driving of the belt conveyor 22 and reaches the carry-out port 36. When the carry-out door 36A is opened, the two food transport racks 31 are separated from each other. It is carried out from the carry-out port 36. The delivered food is conveyed to the next step such as a sorting step or a weighing step. After the food transport rack 31 is carried out, the carry-out port door 36A is closed again.

In the food freezing device shown in this embodiment,
Since the food to be frozen is transported while being placed on the plurality of shelves 31C of the multi-stage food transport rack 31,
More foods can be processed at one time, and productivity can be further improved as compared with the conventional food freezing device.

Further, since the carry-in door 28A and the carry-out door 36A which can be opened and closed are provided at the carry-in entrance 28 and the carry-out exit 36 of the tunnel portion 21, the above-mentioned conditions are provided except when the food transport rack 31 is carried in or carried out. The carry-in port 28 and the carry-out port 36 can be closed, the cold heat source gas can be prevented from escaping from the carry-in port 28 and the carry-out port 36, and the use efficiency of the gas can be improved.

Further, the present invention is not limited to the above-mentioned embodiment, and modifications such as those shown in FIGS. 9 and 10 are also possible. The ventilation plate 45 shown in FIG. 9 has an elongated plate shape, and is constituted by overlapping first and second elongated plates 45A and 45B of the same shape having a plurality of round hole-shaped ventilation holes 47. . One of the two elongated plates 45A and 45B is fixed to the inner wall of the tunnel portion 21, and the other is slidable in the direction of arrow (e)-(f) so that it can be fixed at any position. It has become.

In such a ventilation plate 45, the opening degree of the ventilation hole 47 is defined by the relative position of the two elongated plates. By adjusting the opening degree, the flow rate of gas passing through the ventilation plate 45 can be controlled. Therefore, the flow of gas in the tunnel portion 21 can be optimized, and the heat exchange efficiency between the frozen object and the gas can be further increased. Further, FIG. 10 shows a ventilation plate 55 in which the slit-shaped ventilation holes 57 are provided in the ventilation plate 55 in FIG. 9.

Next, FIG. 11 shows another embodiment of the present invention. This example is largely different from the above-mentioned embodiment, in which the carry-in door 28A of the carry-in port 28 of the tunnel portion 21 and the carry-out port 36A of the carry-out port 36 are not provided, and instead, a blocking plate 38 is provided in each of the carry-in port 28 and the carry-in port 28. This is the point attached to the carry-out port 36.

The blocking plate 38 has a substantially U-shaped plate shape,
It is made of a non-breathable material such as synthetic resin, metal, or wood. The blocking plate 38 includes a food transport rack 31, an upper inner edge 38A and a side inner edge 38B of the blocking plate 38 when the food transport rack 31 enters and leaves the opening formed by the blocking plate 38 and the belt conveyor 22. Are provided close to each other.

In the food freezing device of this example, the blocking plate 38 is made of a non-breathable material, and the food transport rack 3 is used.
The first side plate 31B is also made of a non-permeable material, and the gap between the food transport rack 31 and the blocking plate 38 is extremely small. Therefore, the food transport rack 31 is connected to the carry-in port 28.
When entering or exiting through the carry-out port 36, the gas in the tunnel portion 21 is blocked by the blocking plate 38 and the food transport rack 31 and does not easily escape from the carry-in port 28 or the carry-out port 36.

In the food freezing device of this example, the escape of gas can be prevented without providing doors at the carry-in port and the carry-out port, and the utilization efficiency of the cold heat source gas can be improved. Further, since the door need not be opened / closed, the operation is easy.

[0041]

EXAMPLES Next, the effects of the present invention will be demonstrated with reference to experimental examples. (Experimental Example 1) Using the food freezing device 20 of the present embodiment shown in FIG. 1, each packed hamburger 10 weighing 80 g.
00 freeze treatments were performed. Temperature controller 26 at this time
Was set to −100 ° C., and the average driving speed of the belt conveyor 22 was set to 0.33 m / min. Also, the processing time is 2
It was set to 0 minutes, and the number of shelves 31C of the food transport rack 31 was set to three levels. Liquefied nitrogen was used as the low temperature liquefied gas.

The temperature of the exhaust gas discharged from the exhaust mechanism 44 of the food freezing apparatus of this example was -10 ° C. In addition, the tunnel part 2 required to freeze this packed hamburger
The length of 1 was about 7 m.

Comparative Example 1 Using the conventional food freezing apparatus shown in FIG. 12, 1,000 pieces of packaged hamburgers weighing 80 g each were frozen. The average drive speed of the belt conveyor 22 at this time was set to 1.0 m / min. The other test conditions were the same as in Experimental Example 1.

The temperature of the exhaust gas discharged from the exhaust mechanism 44 of the food freezing apparatus of this example was -50 ° C. The length of the tunnel portion required to freeze the packaged hamburger was about 20 m.

From these results, it was found that when the conventional food freezing device was used, the difference between the temperature of the exhaust gas and the temperature (-196 ° C) of the nitrogen gas during vaporization was 146 ° C. On the other hand, when the freezing process was performed using the food freezing apparatus of this example, the temperature difference was as large as 186 ° C. Therefore, it was found that by using the food freezing device 20 of this example, the sensible heat of the supplied nitrogen was utilized 27% more than when using the conventional device. Further, the heat quantity including the latent heat of vaporization of the supplied nitrogen at this time is 11.8 as compared with the case of using the conventional food freezing device.
It was used a lot. Further, it was found that the food freezing device 20 of the present embodiment can perform the same amount of freezing process with a device smaller than the conventional device.

[0046]

As described above, in the food freezing apparatus according to the present embodiment, the gas flow meandering adjusting mechanism composed of a plurality of stirring fans and straightening vanes is provided inside the tunnel portion. The gas of the cold heat source flows in the longitudinal direction while meandering in a zigzag shape in the tunnel portion. As a result, the gas flow path is long, the flow velocity is high, and the heat exchange efficiency between the frozen material and the cold heat source gas is high. Therefore, it is possible to satisfactorily perform freezing treatment on a frozen object having a high initial temperature or a packaged frozen object.

Further, since the food to be frozen is conveyed while being placed on the shelves of a multi-stage food conveying rack, more food can be processed at one time, and the conventional food freezing device can be used. The productivity can be further improved as compared with.

Further, by providing the ventilation plate having the ventilation holes inside the tunnel portion, a part of the gas in the tunnel portion can pass in the carrying-in direction. Further, the rest of the gas circulates in a predetermined section in the tunnel portion in a substantially 8-shape. The flow of the gas can be lengthened and the flow velocity can be increased by the circulation motion of the substantially 8-shape, and the heat exchange efficiency between the frozen substance and the gas can be further enhanced.
Further, since a part of the gas can pass in the carry-in direction, the meandering flow of the gas in the longitudinal direction becomes smooth.

Further, by making it possible to adjust the opening degree of the vent holes of the vent plate, the flow rate of gas passing through the vent plate can be controlled. Therefore, the flow of gas in the tunnel portion can be optimized, and the heat exchange efficiency between the frozen material and the gas can be further increased.

Further, by providing a carry-in door and a carry-out door that can be opened and closed at the carry-in entrance and the carry-out exit of the tunnel part, the carry-in entrance and the carry-out exit except when the food transport rack is carried in or carried out. The gas can be closed, the gas can be prevented from escaping from the carry-in port and the carry-out port, and the use efficiency of the gas can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a food freezing device of the present invention.

FIG. 2 is a side view of the food freezing device shown in FIG.

FIG. 3 is a perspective view showing a food transport rack of the food freezing device of the embodiment.

FIG. 4 is a view showing a carry-in door of the food freezing device of the embodiment,
(A) shows a closed state and (B) shows an open state.

5 is a cross-sectional view taken along the plane AA ′ of the food freezing device shown in FIG. 1.

FIG. 6 is a perspective view of the food freezing device shown in FIG. 1.

FIG. 7 is a plan view showing the food freezing device shown in FIG. 1.

FIG. 8 is a view showing a ventilation plate of the food freezing device shown in FIG. 1.

FIG. 9 is a diagram showing a modified example of the ventilation plate of the food freezing device shown in FIG. 1.

FIG. 10 is a diagram showing a modified example of the ventilation plate of the food freezing device shown in FIG. 1.

FIG. 11 is a view showing another embodiment of the food freezing device of the present invention.

FIG. 12 is a plan view showing an example of a conventional food freezing device.

[Explanation of symbols]

20 ... food freezing device, 21 ... tunnel part, 22 ... belt conveyor, 23 ... stirring fan, 28 ... carry-in port, 28A ... carry-in door, 31 ... food transport Rack, 31
C ... Shelf, 32 ... Current plate, 35, 45, 55 ... Ventilation plate, 36 ... Outgoing port, 36A ... Outgoing door, 37, 47,
57 ... Vent hole, 43 ... Low temperature liquefied gas supply mechanism, 44 ...
-Exhaust mechanism, 48 ... Gas flow meandering adjustment mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuji Nishimura 4-320 Tsukagoshi, Sachi-ku, Kawasaki-shi, Kanagawa Japan Oxygen Co., Ltd.

Claims (5)

[Claims] 1. A tunnel portion having a carry-in port and a carry-out port at both ends, and a belt conveyor for transporting a frozen substance, the inside of the tunnel part being arranged along a longitudinal direction extending from the carry-in port to the carry-out port, In a food freezing device comprising a low-temperature liquefied gas supply mechanism for supplying a low-temperature liquefied gas into the tunnel part, and an exhaust mechanism provided on the carry-in side of the low-temperature liquefied gas supply mechanism of the tunnel part and discharging the gas in the tunnel part , A gas flow meandering adjustment mechanism is provided inside the tunnel portion to cause the gas in the tunnel portion to meander in the longitudinal direction, and a plurality of shelves on which the frozen object is placed are provided on the belt conveyor, and the gas flow is provided. A food freezing device, characterized in that a food transport rack whose direction can be ventilated is placed. 2. The gas flow meandering adjusting mechanism is composed of a plurality of agitation fans that flow gas in a lateral direction that traverses the longitudinal direction of the tunnel portion and a plurality of rectifying plates that block the flow of gas toward the carry-out port. The agitating fan is provided on both side walls of the tunnel portion at intervals in the longitudinal direction, and the relative position between the two sides is displaced, and the straightening vane is on a carrying-in direction side of the agitating fan,
The food freezing device according to claim 1, wherein a tip of the food freezing device is provided in the vicinity of a food transportation rack that is transported on the belt conveyor. 3. A ventilation plate is provided inside the tunnel portion, the ventilation plate having a ventilation hole for flowing a part of gas in a predetermined compartment in the tunnel portion toward a carry-in port and circulating the rest in the predetermined compartment. 3. The food product according to claim 2, wherein the ventilation plate is provided on the side of the outlet of the stirring fan in the vicinity of the food transport rack, the tip of which is carried on the belt conveyor. Freezing device. 4. The food freezing device according to claim 3, wherein the ventilation plate is configured such that the opening degree of the ventilation hole can be adjusted. 5. The carry-in door and the carry-out door are respectively provided at the carry-in entrance and the carry-out exit of the tunnel portion so as to be openable and closable, respectively. Food freezing equipment.