JPS6024846A - Heat sterilizing treatment of hermetically container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating method for treating yellow-sealed containers, and more specifically, the present invention relates to a method for heating and painting yellow-sealed containers. This invention relates to a method for killing a sealed container having a flexible wall portion and having strength and self-shape retention in a pressurizing and heating stage 1-4 kettle.

In order to reduce material costs, the notebook is made from a relatively thin plastic notebook or a laminate made of plastic film and metal 11, which has self-shape retention at a certain temperature, but cannot be swayed by internal or external pressure during heat sterilization. A cup-shaped container whose walls are prone to permanent deformation, i.e., a head space or space is left in the cup-shaped container body with relatively low rigidity, is used to store moisture-containing contents, such as red rice, beans, and similar products, or curry, suits, etc. After filling the fluff with a liquid material such as, a sealed container formed by heat-sealing a filling lid to the fluff part, the sealed container is heated under pressure (49. The temperature is 85°C or higher, especially 1. When processing the contents at a heating stage lΔ゛j at a temperature below OO℃, if there is a difference between the internal pressure of the container and the pressure inside the sterilization pot, the wall (or lid and bottom wall in the unknown potagraph) The product value is likely to be lost due to permanent deformation in convex or concave shapes (including the part (called a villa)).
Particularly when this pressure difference is large, troubles such as the heat-sealed portion peeling off, resulting in loss of sealing performance, or in extreme cases, the wall portion rupturing, are likely to occur.

Such troubles are also likely to occur in sealed containers made of plastic bottles that have relatively low rigidity walls.

In order to prevent the above-mentioned troubles, heat sterilization is carried out so that there is no pressure difference between the internal pressure of the sealed container and the internal pressure of the sterilization pot, or normally this pressure difference is maintained within approximately 0.31℃g/cln2. There is a need.

In order to carry out such heat sterilization treatment (d) detect the internal pressure of the sealed container in an undeformed state during this treatment,
The pressure within the sterilization pot may be shifted by 1iill so that it becomes substantially equal to this detected pressure. Regarding this internal pressure detection method, Japanese Patent Application Laid-Open No. 52-54576) ijlQ describes a method of directly measuring the internal pressure. However, in this case, a rigid model container is required whose walls do not change due to pressure differences between the inside and outside. And this model container is
Although it must have the same shape as the sealed container and have substantially the same thermal conductivity, it is often difficult and impractical to obtain such a model container.

Another method is to observe slight deformations such as dents and bulges in the wall of the container through the viewing window of the heat sterilization pot, and then check to ensure that these deformations return and the wall returns to its normal shape. One possible method is to control the pressure in the sterilization pot, but this method requires manual operation and is difficult to automate.

It is an object of the present invention to solve the problems of the prior art described above.

In order to achieve the above object, the present invention provides a self-shape-retaining seal that is filled with a water-containing content leaving a head space and is sealed, has a wall portion that is susceptible to permanent deformation during heat sterilization treatment, and has a self-shape retention property. A method of sterilizing a container in a pressurized heat sterilization cauldron, wherein the pressure inside the sterilization cautery is maintained at the center during a period in which the temperature of the heating medium in the sterilization cauldron is equal to or higher than the temperature at the center of the head space. during a period in which the heating medium temperature is lower than the center temperature, so that the pressure is substantially equal to the sum of the air partial pressure in the head space corresponding to the center temperature and the saturated vapor pressure of the moisture. Heating of a sealed container characterized by controlling the pressure to be substantially equal to the sum of the air partial pressure in the head space corresponding to the temperature of the heating medium and the saturated vapor pressure of the moisture corresponding to the temperature of the heating medium. A stage IYJ processing method is provided.

The present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a hot water type pressurized and heated sterilization pot (so-called retort), in which hot water 3 sent from a hot water tank 2 is stored leaving a space 4.

5 is a pressurized air pipe for increasing the air pressure in the space 4 to the required pressure; 6 is a pipe for increasing the temperature of the hot water 3 in the second stage of heating, and a predetermined sterilization temperature lf, lIl t；'＋
The steam pipe 7 is a cooling water pipe for lowering the temperature of the hot water 3 during the cooling period. Dimension 8 is a throat air pipe for reducing the pressure in space 11. +! ',b
The water is heated by a ring system (not shown) during operation, so that the water level distribution in the sterilization pot J becomes uniform.

10 is a sealed container, which includes a cup-shaped container body 11;
The flange portion 11a is equipped with a heat 7-leaf lid portion 12, and a head space 13 (approximately 10 to 40 volumes relative to the normal internal volume) is left inside so that the moisture-containing contents 14 can be In this example, it is filled and sealed at 20°C.

The container body 11 has a self-shape retaining property at room temperature, but is composed of a wall portion that is easily permanently deformed by external pressure or internal U-E during heat sterilization treatment. That is, it is relatively thin, for example, about 0.0 mm thick. 1I ~ 1.01J, polypropylene sheet or polyzolopylene-carboxylic [5 layers of modified polypropylene-ethylene vinyl alcohol copolymer-carboxylic acid modified polypropylene-polypropylene]: next GT layer (for example, polyurethane-based)
It is formed by molding a laminate made of gold E15 Fri (for example, aluminum foil) or a blank made of a single piece of gold by vacuum forming, press forming, or the like. The lid portion 12 is also made of the above-mentioned material.

Although not shown, a similar sealed container 10 is typically
F of the contents is immersed in hot water 3 and heated under pressure to a predetermined temperature between 85°C and 15'0°C.

They undergo heat sterilization treatment according to their value.

15 is a temperature sensor for measuring the temperature of the hot water 3 (that is, the temperature of the heating medium), and 16 is attached to a suitable sealed container 1o so as to be able to measure the temperature at the center of the head space 3. temperature sensor. Temperature sensor 1
The outputs of 5 and 16 (usually on the order of mV) are amplified by amplifiers 17 and 18, respectively, and then input to a programmable arithmetic unit 19.

The calculator J9 compares the hot water temperature (Tr) and the headspace center temperature (Th), and when Tr≧Th, if the output of the shim sensor 15 is greater than the output of the sensor 16,
Figure 2 (this figure will be explained later) shows the saturated vapor pressure Pw of water and the headspace air partial pressure Pao corresponding to Th.
Outputs the sum pl (voltage conversion value), and when Tr<Th,
If the output of the sensor 15 is smaller than the output of the sensor 16, as shown in Fig. 2, the saturated vapor pressure P of water corresponding to Tr is
w and I of the headspace air partial pressure Pa corresponding to Th
f]'i) A program that instructs to output 2 (voltage conversion value) has been saved from the programmer 20.

The output from the arithmetic unit 19 is sent to a signal converter (not shown).
The signal is inputted to the current-air pressure converter 21 via the current-air pressure converter 21, and is converted into an air signal. The way the converter 21 comes out is the pressure controller 2
2, the pressure controller 22 connects the pressurized air piping 5
The pressure inside the sterilization pot 1 is adjusted to the above p by opening and closing the control valve 23 provided at the
, and is controlled to be equal to P2. In the above case, only the honeymoon container 1o to which the temperature sensor 16 is attached is not a product, but another sealed container 1o that has been subjected to exactly the same heating and cooling process is a product.

In addition, FIG. 2 shows the temperature Tr or Th, the space complex partial pressure (Pa curve), and the saturated vapor pressure of water (Pw fusion) when the contents 14 are filled and sealed at 20°C. Show relationships. The wire was calculated based on the Boyle-Chassis law, assuming that the influence of thermal expansion of the contents 14 was negligible.

Figure 3 shows the hot water temperature Tr (curve 1) and the temperature at the center of the contents (curve 2) during heat sterilization of the sealed container 1o in the sterilization pot 1.
) and headspace center temperature Th (curve 3) over time (see Examples below)
. The temperature at the center of the contents is at the specified heating temperature (this J device stand is 1
Tr
2T1□) Ox, the hot water temperature Tr is higher than the headspace center temperature U Tll, Tr>Th, but the time ti
When the temperature reaches 1, the valve 25 of the cooling water pipe 7 and the valve 26 of the hot water return pipe 9 are opened, and the hot water 3 is replaced with cooling water, and suddenly (the cooling heel contents and the center of the head space 1jl
(The temperature decrease is delayed even further and becomes Tr<Th. In this specification, hot water 3 is used as: i in the middle, or (
The temperature of the replaced cooling water is also called the hot water temperature or heating medium temperature.

In the following heating and cooling process, it is essential that the internal pressure of the container be substantially equal to the pressure of the sterilization pot to prevent problems such as permanent deformation of the sealed container. As a result of the ItIF investigation, the internal pressure of the container is Tr≧
ThO is substantially equal to the sum P1 of the air partial pressure Pa in the headspace and the saturated vapor pressure Pw of water in the content 14, determined from the headspace center temperature Th, while Tr
< During Th, f, to, is determined from the center temperature of the space, Th, to /j, the air partial pressure Pa of the space, and the hot water temperature 1
fTr': It has been found that it is substantially equal to the sum P2 of the saturated water vapor pressures Pw.

The reason for this is assumed to be as follows. That is, Tr〉Th
0, the internal pressure of the container is equal to the sum of the partial pressure of the residual air and the saturated water vapor pressure of the water evaporated from the contents 14 into the space J3. Part 1 - Partial pressure and saturated water vapor partial pressure are functions of temperature, or the temperature in the headspace 13 is not uniform! j1'(ill! The area near the hot water temperature Tr is relatively high, while the area near the top surface of the content 14 is relatively high.
relatively low, approaching the temperature of 4. However, while this temperature difference tends to decrease due to the convection phenomenon, the temperature of the space as a whole increases. Therefore, the temperature at the center of the head space 13 is considered to be approximately the average temperature of the head space portion 13.

On the other hand, when Tr<Th, the temperature of the wall approaches Tr,
Since the temperature is lower than that of the nearby head space, water vapor in the head space condenses on the inner surface of the wall, reducing the saturated water vapor pressure. This tendency becomes more pronounced as Tr becomes lower. Therefore, the saturated water vapor pressure in the head space 13 is controlled by the hot water temperature (mostly the temperature based on the cooling water) Tr, but this is because this phenomenon does not occur in the case of air partial pressure. Guessed.

The nine points in FIG. 4 indicate the container internal pressure calculated according to the method of the present invention described above for the case of the heating/cooling cycle shown in FIG. On the other hand, the curve based on the actual record shows that the sealed container 10 having the structure described in the example below is stored in the sterilization pot 1 and sterilized in the above cycle, and the container wall is observed through the viewing window to see if its deformation is observed. This figure shows the temporal variation in pressure when the sterilization pot pressure is manually adjusted to prevent this from occurring. It can be seen that the two are in good agreement.

The present invention is not limited to the above examples; for example, the contents may be filled and sealed at a temperature other than 20°C, such as 50°C.
You can also do it with However, in this case, it is necessary to maintain the position of the air partial pressure straight line Pa in FIG. 2 so that the sum of the vapor pressure and the air partial pressure at 50° C. is 1 atm.

Also, the sealed container is better! : It's good to have a lonely θ○ in a busy plastic ball of 7λq meat.

Furthermore, a steam-air type 0 pressurized heat sterilization pot may be used.

According to the present invention, a rigid model container that is difficult to manufacture is used.
Alternatively, it is possible to make the internal pressure of the sealed container substantially equal to the pressure inside the pressure and heat sterilization kettle without having to take the trouble of monitoring the deformation of the sealed container during the pressure and heat sterilization kettle. This has the effect of preventing troubles such as permanent deformation and rupture of the sealed container.

Examples will be described below.

Example: From a polypropylene sheet with a thickness of 0.6 μm. Internal volume: 2
A cup-shaped container 11 of 00 cc was formed and filled with 80 cc of curry e at 20° C. leaving a head space 13, and then the lid 12 was heat-rolled into the 7 tank portion 11a and sealed. The lid part 12 had an inner layer of a polypropylene film with a thickness of 70 μm, an intermediate layer of an aluminum foil with a thickness of 9 μm, and an outer layer of a polyester film with a thickness of 12 μm.

For one of the sealed containers 10 formed in this way, a temperature sensor consisting of a thermocouple is attached to the center of the space and the center of the contents, and the distance between the lead wire and the container wall is completely closed using an attachment. I sealed it. 800 of the above sealed containers 10 with temperature sensors and ordinary similar sealed containers 10 in which no additional temperature sensors could be installed were housed in a hot water pressurized heat sterilization pot of the type shown in FIG.

Next, hot water 3 was fed through the hot water tank 2 and into the pot 1, and then the valve 27 of the steam pipe 6 was opened to send steam to heat the hot water 3 at 120° C. in the trench. After the temperature at the center of the headspace and the center of the content 14 reaches 120°C and the predetermined Fo value is added by /114, the valve 27 is closed and the valve 25
was opened and cooling water was introduced to replace the hot water.

The heating and cooling cycle at this time is shown in FIG.

During this time, the amount of air fed into the sterilization pot and the amount of exhaust air discharged from the sterilization pot 1 are adjusted according to the method described above using the programmable sterilization device] 9 and the pressure controller 22, and the pressure inside the sterilization pot is adjusted. was controlled. 1. Close the container through the viewing window during work. Although the deformation of the wall of 0 was observed, almost no deformation was observed. The temperature of contents 14 is approximately 30℃
After that, the sterilization pot was opened and the sealed containers were taken out, but no abnormality such as deformation was observed in all of them.

For the /ζ point of comparison, it is the same as above except that Pw in the period of Tr < Th was input to one counter using the programmer 20 so as to be detected based on the headspace center neck IS temperature Th. However, in this case, all the sealed containers 10 suffered from concave deformation.

[Brief explanation of drawings]

FIG. 1 is an explanatory drawing showing an example of an apparatus for carrying out the present invention, FIG. 2 is a diagram showing an example of the relationship between air partial pressure and saturated water vapor pressure in the head space of a sealed container, and temperature. Figure 3 is a diagram showing an example of the relationship between the temperature of hot water in a pressurized heat sterilizer, the temperature at the center of the head space of a tightly sealed container, and the temperature at the center of the contents and time, and Figure 4 is a diagram showing the method of the present invention. It is a diagram showing the relationship between the internal pressure of a sealed container calculated based on the above, and the sterilization pot pressure and time at which no deformation occurs in the sealed container. 1... Pressure heating sterilization pot, 10... Sealed container, 13 Height space, 14... Contents. Figure 1 Atsushi Figure 2 Humidity Tr, Th (°C)

Claims (1)

[Claims] (1) A self-retaining container with a wall portion that is easily permanently deformed during heat sterilization, filled with water-containing contents leaving a head space, and sealed. 7. A method of sterilizing in a pressure heating sterilization pot,
During the period when the pressure inside the germination pot is below the temperature of the heating medium in the pot, the temperature of the head space corresponding to the seven grades of the center section is maintained. Illusion partial pressure and saturation of the water; , 1 liter so that the pressure is substantially equal to the sum of the partial pressure of air in the space and the saturated vapor pressure of the moisture corresponding to 7 degrees of the heating medium.
A method for heat sterilization of a honeymoon container, characterized in that it is sterilized by heating.