JPH0636396B2 - Microwave heating sterilizer - Google Patents

Description

The present invention relates to a microwave heating sterilizer,
In particular, the present invention relates to a microwave heating sterilization device that reduces variations in heating temperature during sterilization of an object to be sterilized.

[Prior art and its problems]

Many methods have been reported for continuously heating and sterilizing a package in which the object to be sterilized is packed in a bag or a container by microwaves.However, in any method, heating during sterilization of the package is performed. The temperature tends to be high in the peripheral part and low in the central part. In particular, the tendency is high for solid substances or high viscosity products to be sterilized without convection, and therefore in actual sterilization, it was necessary to perform temperature control at the heating temperature in the central portion where the temperature becomes low. As a result, the peripheral area where the temperature rises becomes overheated, which adversely affects the quality.

It is also possible to perform microwave irradiation intermittently and to make the temperature of the package uniform by heat conduction during non-irradiation, but in the sterilized object without convection, the temperature difference of 10 ° C can be eliminated. However, at least 3 minutes are required, and short-time heating, which is a characteristic of microwave heating, becomes impossible.

[Problems to be solved by the invention]

The present invention makes use of the characteristics of short-time heating by microwave,
An object of the present invention is to provide a microwave heating sterilizer capable of minimizing the temperature rise range of the sterilized object in the package and the final temperature variation and downsizing the apparatus.

[Means for solving problems]

Irradiate microwaves while transferring the object to be sterilized that can be heated by microwaves in a container or in a bag.
In a device for heat sterilization, a heating chamber is provided with a waveguide for partially heating one side of a package and a waveguide for heating the entire package on the opposite side.

The details will be described below.

FIG. 1 is an explanatory diagram of an embodiment of a microwave heating sterilizer of the present invention, in which microwaves from the microwave oscillating devices 10A and 10B are guided to the conveyance path of the package A by the waveguides 11A and 12A.
1st heating chamber 1 irradiated via A, 11B, and 12B
A, the second heating chamber 1B is provided, and the waveguide 11A of the first heating chamber 1A extends to a position close to the transport path,
On the other hand, the lower waveguide 12A is located on the chamber wall,
Further, the waveguide 11B of the second heating chamber 1B is located on the chamber wall portion, and the lower waveguide 12B extends to a position close to the transport path.

Then, the package A is supplied to the conveyor 8 and conveyed to the first heating chamber 1A through the microwave trap 5, and the sterilization object in the package A is partially here from above and entirely from below. Then, after passing through the microwave trap 6, the second heating chamber 1B partially heats the package from the lower side and entirely heats it from the upper side, and the sterilized package again passes through the microwave trap 7. It is taken out through.

Here, the distance between the microwave irradiation ports of the waveguides 11A and 12B in the first heating chamber 1A and the second heating chamber 1B and the packaging body is set within a range of 10 to 50 mm by moving the waveguides. Well, the size of the irradiation opening of the waveguide 11A is adjusted by changing the size of the slit attached to the irradiation opening.

In order to partially heat in the first and second heating chambers, the package A is intermittently moved and the waveguide 11A,
Package A so that it is directly above or below the irradiation opening of 2B
It is effective to stop.

For example, in the bag-shaped package A as shown in FIG. 3, in the first heating chamber 1A, the second heating chamber 1B is provided in the central portion 22 of the upper surface.
Then, the lower surface central portion 23 is irradiated with microwaves and heated,
In the second heating chamber, the opposite surface of the package is irradiated and heated to the entire surface including the peripheral portion 21.

Here, in the heating chambers 1A and 1B, partial heating of the package and total heating may be performed on the upper surface and the lower surface in reverse order.

Also, the number of heating chambers is not limited to two.
One heating chamber may be repeatedly provided to perform heating.

Further, as shown in FIG. 2, two or more structures of the first heating chamber may be repeatedly provided.

[Work]

In the heating chamber, one of the upper and lower waveguides extends to the vicinity of the package, so that the irradiated microwave is directly absorbed in the central part of the package without being diffused. .

Since the other waveguide does not extend inward, the irradiated microwave diffuses and is also absorbed around the package.

〔Example〕

As the microwave oscillating devices 10A and 10B of the first heating chamber 1A and the second heating chamber 1B, a microwave oscillating device having an output of 1.3 KW (SMG-130 manufactured by Sanyo Electric Co., Ltd.) was used, and two microwave oscillators were installed respectively. .

Then, of the two waveguides in the first heating chamber 1A, the waveguide 1
1A is attached so as to extend so that the position of the irradiation port approaches the package, and the waveguide 12A is attached so as not to come out of the wall surface, and the waveguide 11B of the two waveguides of the second heating chamber 1B is attached.
Is provided so as not to come out of the wall surface of the heating chamber, while the waveguide 1
2B was provided similarly to the waveguide 11A of the first heating chamber.

And the transfer of the package is performed continuously and intermittently,
The test was performed using the following items to be sterilized.

Items to be sterilized are water, carboxymethylcellulose (hereinafter CM
C) Aqueous solution A (concentration 1.2%, viscosity 4,000 cps), CMC aqueous solution B
(Concentration 2.5%, viscosity 64,000 cps), and konjac.

The sterilized product was heat-sterilized by using a packaging body in which a bag made of a laminated film of stretched nylon / non-stretched polypropylene was filled in an amount of 130 g each.

When the set temperature was 100 ° C. or higher, the package was housed in a glass resin-containing silicon resin support and heated.

The temperature of the package after heating was measured by the thermocouple at the central portion 22 and the peripheral portion 21 shown in FIG.

The conditions for continuous and intermittent transfer are shown in Table-1 and Table-2. In any transfer, the first and second heating chambers 1
There were four packages in A and 1B.

In the case of continuous conveyance, the peripheral portion is heated more than the central portion in the first heating chamber regardless of the object to be heated, and after the second heating is finished, the temperature difference is further widened, and the effect of direct irradiation is I was not able to admit. However, in the case of water, the temperature difference was smaller than that of other heated objects, and the effect of convection was observed. C
Since the MC aqueous solution and the konnyaku showed almost the same tendency under all conditions, the results of temperature measurement with the 1.2% CMC aqueous solution are shown in Table-3.

From the results shown in Table 3, direct irradiation of the microwave to the package A in the first heating chamber or the second heating chamber was effective for heating the central portion during the intermittent transfer. The effect depends on the distance between the irradiation port and the object to be heated, the size of the irradiation port, and the heating time, and it is possible to perform heating with a small temperature variation by the combination according to the shape of the package.

[Effect]

When the apparatus of the present invention is used, the packaging is partially heated by microwaves in the same heating chamber, so that the variation in temperature during heating is small, and the entire packaging is finally evenly heated. It was possible to achieve uniform heating by microwave heating, which was not possible with conventional microwave heating methods.

This makes it possible to reduce temperature variations both during and after the temperature rise inside the package during continuous microwave heat sterilization, preventing a difference in heat distribution during temperature rise and quality deterioration due to excessive heating. Uniform heating can be performed in time.

[Brief description of drawings]

FIG. 1 and FIG. 2 are explanatory views showing an example of the microwave heating sterilization apparatus of the present invention, and FIG. 3 is an explanatory view showing an example of the shape of the package. 1A ... 1st heating chamber 1B ... 2nd heating chamber 10A, 10B ... Microwave oscillating device 11A, 11B, 12A, 12B ... Waveguide A ... Package

Claims (3)

[Claims] 1. A container for sterilizing objects that can be heated by microwaves,
Alternatively, in a device that heats and sterilizes the package by irradiating it with microwaves while moving the package stored in a bag, a waveguide for partially heating one side of the package is provided in the heating chamber, and the entire side is heated on the other side. Microwave heating sterilizer equipped with a waveguide. 2. The microwave heating sterilizer according to claim 1, wherein the transfer of the package is intermittent transfer. 3. The microwave heating sterilizer according to claim 1 or 2, wherein two or more heating chambers are continuously provided.