JPH0460664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cooling an object to be sterilized in a steam retort pot after heat sterilization.

(Prior Art) Conventionally, in steam retort sterilization, the methods shown in FIGS. 2 to 4 have generally been used as a cooling method after sterilization. The method shown in FIG. 2 is a method in which cooling water is showered onto the object to be sterilized from the top of the retort pot 10 using a shower plate 11 to cool the object. According to this method, the object to be sterilized 12 is rapidly cooled by direct cooling water hitting the upper part of the sterilization shelf, which causes a sudden decrease in the internal pressure of the container for the object to be sterilized, and in the case of a molded container, etc., it becomes deformed. Sometimes. Furthermore, it is difficult to uniformly cool the objects 12 to be sterilized stacked in multiple stages in the sterilization shelf. Furthermore, the method shown in FIG.
This is a method of cooling by pouring cooling water from the lower part of the cooling rack, but this method also has the problem of rapid cooling like the above method, and at the same time has the disadvantage that cooling of the upper part of the cooling rack is delayed. Furthermore, although the method shown in FIG. 4 is a combination of both of the above methods, the drawbacks of both methods still remain.

In this way, in the conventional cooling method for steam-type retorts, cooling water is directly introduced into the retort pot, so the object to be sterilized is rapidly cooled, the internal pressure of the container drops rapidly, and the container becomes deformed. This method has problems such as storage and difficulty in uniformly cooling the object to be sterilized. As a measure to solve these problems, the present inventor first proposed a method of cooling only the retort pot body so that the sterilization shelf is not directly exposed to cooling water (Japanese Patent Publication No. 63-57028).

(Problem to be solved by the invention) When sterilizing a molded container with a large head space using a steam retort, it is necessary to control the pressure (isobaric control) to prevent the container from deforming. The biggest problem occurs during the early stages of cooling when rapid temperature changes occur.

The present invention further improves the cooling method proposed above to prevent rapid temperature changes in the initial stage of cooling in a steam retort, and to prevent the sterilization even if the object to be sterilized uses a weak container such as a molded container. The purpose of the present invention is to provide cooling water for retort sterilization, which can be uniformly cooled without causing deformation of the container after cooling is completed, and which can be easily carried out by making slight improvements to conventional equipment. That is.

(Means for solving the problem) As a measure to slow down the temperature change in the initial stage of cooling, it is conceivable to use water that has been heated to near the sterilization temperature as cooling water instead of adding cold water during cooling. However, in this case, in addition to the retort pot, a cooling water heating tank for heating the cooling water is required, and the tank must be a pressure tank, resulting in an expensive equipment problem. The present invention has solved the above-mentioned problems by the following means that do not cause the above-mentioned problems.

That is, in the cooling method for retort sterilization of the present invention, a small amount of cooling water is introduced into the lower part of the retort pot before the sterilization is completed, and the cooling water is heated to almost the sterilization temperature by the steam during the sterilization process, and the cooling process Once inside the retort, the heated cooling water is showered down from the top, and cooling water is gradually introduced into the bottom from the outside to gradually lower the temperature of the cooling water circulating inside the retort. It has a structure that slowly cools the object to be sterilized while controlling the rate of temperature decrease.

(Function) At the start of cooling, the cooling water at the bottom of the retort heated to the sterilization temperature by the steam inside the retort falls on the top of the object to be sterilized, and at the same time, the cooling water is gradually poured into the bottom of the retort. The object to be sterilized is slowly cooled by gradually lowering the temperature of the circulating cooling water. Therefore, by controlling the amount of cooling water introduced from the outside, the rate of temperature drop can be controlled, and the object to be sterilized can be slowly cooled.
As a result, there is no sudden temperature drop due to water supply after sterilization, and uniform cooling is possible without deforming the container. moreover,
Since there is no need to provide special equipment such as a cooling water heating tank, it can be carried out with almost no modification to conventional equipment.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is an explanatory diagram of the configuration of an apparatus that implements the cooling method in retort sterilization of the present invention. In the figure,
Reference numeral 1 denotes a retort pot, in which objects to be sterilized 2 stacked in multiple stages on a sterilization shelf (not shown) are stored. 3 is a steam pipe for introducing steam into the retort pot, which introduces steam into the sealed retort pot to sterilize objects to be sterilized at high temperature. The above is similar to the conventional steam-type retort apparatus, but the retort apparatus that implements the method of the present invention further includes a cooling water pipe 4 that introduces cooling water into the bottom of the retort pot, and a cooling water pipe 4 that introduces cooling water into the bottom of the retort pot. It has a cooling water circulation pipe 5, a pump 6, and a shower plate 7 for circulating cooling water and showering it onto the object to be sterilized. Note that 8 and 9 are flow control valves such as electromagnetic valves.

In the apparatus configured as described above, the cooling method of the present invention is implemented as follows.

Shortly before the end of sterilization of the object 2 introduced into the retort pot 1, as shown in FIG. The steam introduced into the retort pot heats it to sterilization temperature. The timing for introducing the cooling water into the retort pot may be determined by taking the time necessary for the cooling water to be heated to the sterilization temperature before sterilization is completed. Note that since the cooling water is introduced into the lower part of the retort pot, even if the cooling water is introduced into the retort pot during sterilization, the sterilization temperature near the sterilization shelf is not affected and the pressure does not decrease.

When sterilization is completed and the cooling process begins, the pump 6 is activated to cause the heated hot water in the lower part of the retort pot to fall from the upper part via the circulation pipe 5 onto the object 2 to be sterilized from the shower plate 7. . At the same time, cooling water is gradually introduced into the lower part of the retort pot via the cooling water pipe 4 and circulated by the pump 6.
The object to be sterilized 2 is gradually cooled. Thereby, the object to be sterilized can be slowly cooled while controlling the rate of temperature drop.

(Effects) The present invention has the above configuration, and can control the rate of temperature drop by starting cooling at the sterilization temperature and then controlling the amount of cooling water introduced from the outside. , the object to be sterilized can be slowly cooled. Therefore, since there is no sudden temperature drop at the start of sterilization, the container does not deform and moreover, uniform cooling is possible. Furthermore, there is no need to provide a special device such as a cooling water heating tank, and the method can be easily implemented with almost no modification to conventional equipment, resulting in remarkable effects.

[Brief explanation of the drawing]

FIGS. 1a and 1b are schematic configuration diagrams of a retort device schematically showing an embodiment of the cooling method of the present invention, and FIGS. 2 to 4 are schematic configuration diagrams of a retort device showing a conventional cooling method. . 1, 10: retort pot, 2, 12: object to be sterilized,
3: Steam pipe, 4: Cooling water pipe, 5: Cooling water circulation pipe, 6: Pump, 7: Shower board.

Claims (1)

[Claims] 1 In the retort sterilization method in which the object to be sterilized is stored in a retort pot and sterilized by heating with steam, cooling water is introduced into the lower part of the retort pot before sterilization is completed, and the cooling water is almost sterilized by the steam during the sterilization process. When the retort is heated to a certain temperature and enters the cooling process, the heated cooling water is showered from the top, and cooling water is gradually introduced from the outside to the bottom to gradually lower the temperature of the cooling water circulating inside the retort. 1. A cooling method for retort sterilization, characterized by slowly cooling an object to be sterilized while controlling the rate of temperature fall within the retort.