JP3025217B2 - Depressurized degassing uniform heating device for steaming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a depressurizing and degassing uniform heating device for a steaming device for steaming processed foods and the like,
In particular, the present invention relates to a depressurized degassing uniform heating device in which degassing performance is improved by injecting steam into the center of a processing object to temporarily recover pressure in the middle of a degassing step.

[0002]

2. Description of the Related Art Steaming apparatuses are used in the processed food field of the food industry, and are particularly used in the thawing, steaming and sterilizing processes of granular solid foodstuffs. Specifically, thawing and steaming of frozen ingredients such as small potatoes and potatoes, steaming of grains such as rice and barley, steaming of beans such as soybeans and peas, meat and potatoes cut to a certain size and frozen or stored at low temperatures -Used for cooking and sterilizing carrots.

[0003] When a processed product such as food is steamed by a steaming device, the processed product is packed in a container called a cage and stored in a steaming device (pot) for steaming. Usually, steaming is performed to improve heat transfer efficiency. The deaeration operation is performed as a pre-process. As this degassing method, a steam degassing method in which air is expelled with steam is generally used. However, in this deaeration method, when the processed material is a small solid food material, sufficient deaeration cannot be performed even for a long time because a small gap is formed between the materials in the cage. For this reason, air remains particularly in the center of the cage, and the residual air causes variations in the temperature of the processed material between the periphery and the center of the cage, resulting in so-called boiling unevenness. In order to prevent such non-uniform boiling, a vacuum repressurization degassing uniform heating method has already been proposed and patented by the present applicant (Japanese Patent Publication No. Hei 4-30804). According to the vacuum depressurization degassing uniform heating method, the residual air in the steaming apparatus can be significantly reduced.

[0004]

However, in the case where the processed product is a solid food material stored frozen or immersed at a low temperature, the processed product can be degassed even if vacuum depressurization is performed at a normal vacuum level. Air spots remain in the center of the boiler, causing uneven boiling. This air spot is caused by the low saturated vapor pressure due to the low temperature of the processing object, and in order to solve this, it is necessary to evacuate to a higher vacuum than the saturated vapor pressure corresponding to the temperature of the processing object There is. However, if the temperature of the processed material is, for example, 0 ° C., the corresponding saturation pressure is 4.6 Torr, and if the temperature is 10 ° C., 9.2.
The pressure becomes very low as in Torr, and in order to eliminate the air spot, it is necessary to evacuate at a pressure even lower than such a low saturation pressure, which requires a long deaeration operation. The working efficiency of the deaeration treatment is greatly reduced, and the running cost is also greatly increased.
In addition, if the air spot is temporarily reduced to 4.6 Torr
r, the saturated steam temperature in the system becomes 0
° C or less, which causes the residual water around the treated material to freeze, preventing normal operation.

[0005] For this reason, conventionally, only low-pressure degassing at a normal evacuation level (20 to 100 Torr) could be performed on a low-temperature processed material. It is unavoidable that rare air remains in the gap as an air spot. Residual air tends to collect in the center of the processed material, which is a low temperature area. As a result, when the pressure is restored by steam and the temperature is raised, an air spot with a relatively high residual air concentration is generated in the center of the processed material. . Therefore, the tendency of the vapor invading from the wall surface of the cage filled with the processing object to condense at the air spot portion and to be drained while transferring heat to the processing object is further increased.

[0006] As described above, since the periphery of the air spot is surrounded by the drain of the repressurized steam, the elimination of air in the air spot does not proceed easily, and the heat transfer performance in this part is extremely poor due to the residual air. The steaming process is performed as it is. In the steaming process, the heat transfer performance of the air spot part is poor, and the drain around the air spot part disturbs and it is difficult for the heating steam to reach the air spot part. Does not rise easily, and uneven steaming occurs at the periphery and the center of the cage. This phenomenon becomes more conspicuous as the temperature of the processed material is lower and as the size of the cage is larger in the cage.

It is an object of the present invention to significantly reduce the residual air in a steaming apparatus in a short time even when a large amount of processed material filled in a large cage is processed by steaming at a low temperature. It is an object of the present invention to provide a recompression degassing uniform heating device of a steaming device capable of improving degassing efficiency and reducing steaming unevenness without generating an air spot in a section.

[0008]

Means for Solving the Problems] condensate deaeration uniform heating apparatus because the present invention to solve the above problems, a processed product such as food
A container for filling is accommodated in the processing tank, and
Into a steaming device that introduces steam into
In the above, from the nozzle insertion port formed in the wall of the container
A number of steam holes extending along the center of the vessel
One or more steam injection pipes on the surface;
Steam supply with a nozzle that can be detachably connected to the
The nozzle is attached to and detached from the supply pipe and the nozzle insertion port.
Moving means for reciprocating the steam supply pipe to make the steam supply pipe reciprocate.
Be prepared.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a shows a schematic cross section of a lateral置筒shaped cooking device 1, valve V ₂ is the same device, V
A steam pipe 2 and 4 with a _4, a drain pipe 5 valved V _5, V _6, the vacuum suction pipe 3 with the vacuum source valve V ₇ leading to the vacuum pump P is connected. A plurality of (only four are schematically shown in the illustrated example) cages (containers) 6 are accommodated in the steaming apparatus 1. As shown in FIG. 2A, each cage 6 is formed in a box shape having a large number of small holes 7 on its wall surface using a punching metal or the like. The small holes 7 are provided in order to facilitate the air movement in the primary deaeration and the secondary deaeration described later and the steam movement in each step of the decompression and the steaming. The stoma 7 is not essential. Each cage 6 is opened and closed by opening the lid 8 at the end of the steaming apparatus 1.

A circular nozzle insertion port 10 is formed at the center of the bottom wall of the cage 6, and a steam injection pipe 12 that rises vertically inside the cage 6 and is closed at the upper end is connected to the nozzle insertion port 10. It is arranged. The steam injection pipe 12 has a large number of steam holes 14 formed on its peripheral surface and upper end surface.
The steam from the steam hole 14 at the upper end of the steam injection pipe 12 passes through without effectively acting on the processing object F, and may cause a pressure loss in the steam supply pipe 16 instead. ), The steam holes 14 may not be provided at the upper end of the steam injection pipe 12 located on the surface layer side of the processing object F. Further, in the case of a large cage 6 or the like, a plurality of steam injection pipes 12 may be provided at predetermined intervals so as to sufficiently spread the steam to the processing object inside.

A steam supply pipe 16 is provided at the bottom of the steaming apparatus 1 so as to be vertically movable along the longitudinal direction thereof. A lower part near both ends of the steam supply pipe 16 is connected to a piston rod 20 of a vertical hydraulic cylinder 18 as a moving means of the steam supply pipe 16 via a pin 22 as shown in FIG. The steam supply pipe 16 moves up and down in parallel by the expansion and contraction of the hydraulic cylinder 18.
The portion where the piston rod 20 penetrates the bottom wall of the steaming device 1 is hermetically sealed. On the upper surface of the steam supply pipe 16, the same number of nozzles 24 as the number of cages 6 project upward, and when the valve V ₄ of the steam pipe ₄ is opened, steam is jetted from each nozzle 24. These nozzles 24
Can be detachably connected to the nozzle insertion port 10 at the bottom of the cage 6.

The recompression degassing uniform heating device of the steaming device 1 is configured as described above, and the recompression degassing uniform heating method using this device 1 is executed in the following procedure.

First, the processed material F is filled in the cage 6 outside the steaming apparatus 1. A required number of cages 6 filled with the processed material F are accommodated inside the steaming apparatus 1 by opening the lid 8. After the housing of the cage 6, the lid 8 is closed and the primary deaeration in the apparatus 1 is started. The primary degassing vacuum pump to open the vacuum main valve V ₇ P
Is performed. At this time, the valves V ₂ and V ₄ are closed. Also, normally opening the valve V ₆ with the valve V ₆ with opening the valve V ₅ leave closed, closes the valve V ₅ only when needed for drainage. Thus the water accumulated in the drain pipe 5 between the valve V ₅ and the valve V ₆ is drained from the drain outlet.

[0016] After the end of the primary degassing, to close the vacuum main valve V _7. At the same time, the hydraulic cylinder 18 is extended to start the pressure recovery step. When the hydraulic cylinder 18 is extended, the nozzle 24 is connected to the nozzle insertion port 10 in the bottom wall of the cage 6. Opening the valve V ₄ of the steam tube 4. As a result, the steam is squirted from the steam injection pipe 12 vigorously, and the steam is injected radially outward from the center of the cage 6.
As a result, the air remaining between the processing objects F around the steam injection pipe 12 is expelled from the small holes 7 and the upper end opening 26 on the side surface of the cage 6 and accumulates in the space of the apparatus 1. At this time, the steam injection time is such that the temperature of the processing object F at the center of the cage 6 becomes a predetermined temperature higher than the saturation temperature corresponding to the ultimate pressure in the secondary degassing described below, and In order to maintain quality, it is preferable that the preheating is minimized so as not to cause excessive preheating.

Next, the valve V ₄ and the drain valve V ₅ of the steam pipe 4 are closed, and the vacuum source valve V ₇ of the vacuum suction pipe 3 is closed.
Again to perform secondary degassing. In this secondary deaeration, residual air that has been expelled from the cage 6 into the space of the apparatus 1 and accumulated is removed from the outside of the apparatus 1 by evacuation. Also,
When the pressure in the apparatus 1 decreases, the condensed vapor drain remaining around the processing object F in the central part of the cage 6 which has been relatively hot due to the immediately preceding vapor injection reboils and becomes a vapor and disperses to the surroundings. The dilute air persistently remaining around the processing object F is effectively expelled to the outside of the cage 6 by the dissipative diffusion force of the vapor, and is discharged to the outside through the vacuum suction tube 3.

[0018] After the secondary degassing has been completed, usually increased in temperature and the cooking process is performed by opening the valve V ₂ according to a conventional method. In this case although other valve is closed in principle, may be opened simultaneously with the valve V ₂ is the valve V ₄ is depending on the type of treated product F. When opening the valve V ₂ and valve V ₄ at the same time, it is possible to shorten the cooking time for treated F is Atsushi Nobori from inside and outside. In some cases, the valve V ₂
The opening the valve V ₄ is closed, it is also possible to carry out the heating temperature increase from the center side of the workpiece F only. in this way,
In the present invention, the provision of the steam injection pipe 12 enables the selection of an optimum heating method from a variety of heating methods depending on the type of the processing object F and the like.

[0019] The present inventors have conducted experiments using the same cooking device 1 in order to confirm the differences in the degassing effect of the present onset Ming and conventional manner. 3 and 4 shows the results of this experiment, the present onset Akira 3, 4 is by conventional methods. In the figure, TR1 to 4 indicate the temperature of each portion in the cage 6, TR1 is the temperature near the center of the upper surface of the processed material in the cage 6, TR2 is the central temperature of the intermediate height of the processed material in the cage 6, T
R3 is the temperature near the center of the bottom surface of the processed material in the cage 6, and TR4 is the temperature near the outer peripheral surface of the intermediate height of the processed material in the cage 6. As is clear from the figure, in the conventional method, the temperature inside the cage 6 varies considerably, and particularly, the temperature of the processed material (R3) near the bottom wall of the cage 6 is most shifted. On the other hand, FIG.
According to Ming, together we have all good TR1～3, degree of deviation even TR4 are offset these is negligible. As described above, the fact that the temperature of the processed material F in the cage 6 varies little depending on the location indicates that the thermal conductivity is uniform and good in each part of the processed material F. For this reason, in the steaming step performed after the recompression degassing step, the processed product F can be uniformly and quickly heated, and a high-quality processed food without uneven steaming can be manufactured in a short time.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made.

[0021]

As described above, according to the present invention, during the deaeration step, steam is injected into the central portion of the container to temporarily recover the pressure, thereby releasing the air remaining in the central portion of the container into the jet pressure of the repressurized steam. Forced out of the container, the air remaining around the processed material in the center of the container can be effectively removed, and a large amount of processed material can be filled in low-temperature processed materials or large containers. Even when a product is subjected to a steaming process, a good steaming process with uniform high thermal conductivity can be performed in the steaming step.

Further, the temperature of the processed material in the central portion of the vessel is set to a predetermined high temperature higher than the saturation temperature corresponding to the ultimate pressure for secondary deaeration by the steam decompression, so that the temperature of the central portion of the vessel 6 in the secondary deaeration step is increased. The remaining recompressed steam is evaporated as a vapor, and the dilute air slightly remaining in the center of the container can be removed by the vapor to the outside of the container 6 and out of the steaming device, so that the processed material can be further boiled. Processing becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a steaming apparatus according to one embodiment of the present invention.

2 (A) is a perspective view of a cage, FIG. 2 (B) is a cross-sectional view of the cage, and FIG. 2 (C) is a perspective view of an upper end of a modification of the steam injection tube.

FIG. 3 is a time-temperature curve diagram at each position of a processed material using the decompression degassing uniform heating apparatus according to the present invention.

FIG. 4 is a time-temperature curve diagram at each position of a processed material using a conventional decompression and degassing uniform heating device.

[Explanation of symbols]

1 cooking device 2, 4 steam pipe 5 Drain tube 6 cages 7 stoma 8 cover 12 steam injection pipe 14 steam holes 16 steam supply pipe 18 the hydraulic cylinder 24 the nozzle P vacuum pump V _2, V _4, V _5, V ₆ Valve V ₇ Vacuum main valve

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A23L 1/01 A23L 3/16 A47J 27/16 A61L 2/06

Claims (1)

(57) [Claims] 1. A steaming apparatus for accommodating a container for filling a processed material such as foodstuff in a processing tank and introducing steam into the processing tank to steam-treat the processed material. One or a plurality of steam injection pipes having a plurality of steam holes on the peripheral surface extending along the center in the container from the nozzle insertion hole formed in the nozzle insertion hole; A steam supply pipe having a connectable nozzle; and a moving means for reciprocating the steam supply pipe so that the nozzle can be attached to and detached from the nozzle insertion port. Air uniform heating device.