JP2784505B2 - Powder sterilizer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for sterilizing powders and granules using sterilized steam to sterilize the powders and granules.

(Prior Art) Conventionally, there has been known an apparatus for sterilizing or processing powder or granules such as grains and processed foods using hot air or steam (for example, Japanese Patent Publication No. 1-20859).

In this type of apparatus, heat sterilization is performed by blowing hot air or steam while transferring the granular material in a pressurized container. However, steam has a larger heat capacity than hot air, and thus has a large sterilizing effect. However, since some powders may be deteriorated by heating for sterilization, such as flour, for example, sterilization should be performed at a temperature as low as possible and in a short time.

For that purpose, it is necessary to use saturated steam and use it in a pressurized state to raise the temperature. High temperatures can be achieved by using a large amount of heated steam,
Although a small amount of heat can be used, a large amount of heat including latent heat can be used with saturated steam.

On the other hand, in order to enhance the sterilization effect, it is important to improve the contact between the granular material and a heating medium such as hot air or steam. The sterilization effect was not good. In addition, if the drain generated due to the decrease in the temperature of the steam accumulates in the machine, the powder hardens or blocks and the bacteria cannot be sufficiently sterilized. As a countermeasure, there is a device with a scraper at the tip of the blade (Japanese Utility Model Publication No. 63-5508).

(Objects and Configurations of the Invention) The present invention has been made in view of the point of steam, and has as its object to effectively sterilize powders, especially flour such as flour and buckwheat flour, without deteriorating them in a short time. In order to achieve this object, the powdery granules are saturated under high pressure while being stirred at high speed by a plurality of rod-shaped blades arranged such that the rotation trajectories viewed from the direction perpendicular to the rotation axis are arranged with almost no gap. It is configured to heat by mixing with steam.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

 FIG. 1 shows an embodiment of a sterilization apparatus according to the present invention.

In the figure, reference numeral 1 denotes a hopper holding powder and granules, and 2 transfers powder and granules supplied from the hopper 1 and supplies the powder to a mixer 3 from a powder inlet 3a provided near the left end in a pressure-cut state. The mixer 3 is a material seal screw, and the mixer 3 is a horizontal high-speed mixer in which a stirrer 4 in which a pin 4b as a stirring blade is implanted on a shaft 4a rotatably provided in a cylindrical pressure vessel 3b is arranged. It is. Pressurized container 3b
A powder outlet 3c is provided in the vicinity of the right end, and the sterilized powder is discharged via the rotary valve 5.

On the other hand, near the left end of the pressurized container 3b of the mixer 3, the container 3b
Is provided in the tangential direction of. Saturated steam is supplied from a boiler (not shown) via a steam header.

As can be seen from FIGS. 1 (a) and 1 (b), the stirrer 4 is composed of a large number of pins spirally arranged at equal intervals around the rotating shaft 4a.
4b is implanted, and when the rotating shaft 4a is expanded, it becomes as shown in FIG. In FIG. 2, the straight line on which the pins 4b are arranged is the rotating shaft 4a.
Is formed at an angle of 10 ゜ 42 ′ with respect to a line perpendicular to the axis, but is not limited to this angle. The pins 4b are arranged at intervals and in numbers such that the rotation trajectories of the pins 4b are arranged almost without a gap when viewed from a direction perpendicular to the axis of the rotating shaft 4a (indicated by a white arrow in the figure).

Now, in order to sterilize the granular material using the sterilizer having the above-described configuration, the material to be sterilized is transferred from the hopper 1 to the material seal screw 2 while the stirring device 4 of the mixer 3 is rotated at a high speed. And saturated water vapor is blown from the blowing port 6. The granular material is uniformly mixed with the saturated steam while being agitated while being transported by the agitating device 4, thereby being sterilized.

The following table shows that the average number of bacteria is 1 × 1 in the pressure vessel 3a (pressure 1.4 kg / cm ² ) in which the stirring device 4 is rotated at about 800 rpm.
0 While supplying ⁴ flour / g of flour, saturated
The bacteria count when sterilized by blowing at a rate of 250 kg is shown by changing the flour residence time in the container, that is, the sterilization time. Note that, in the present invention, the direction of the saturated water vapor inlet 6 was tangential as shown in FIG.

As can be seen from the above table, the number of bacteria decreased to about 1/15 with a sterilization time of only about 2 seconds, and 1/100
To a degree. In addition, the sterilization effect increases as the residence time of the flour in the container increases, and when the sterilization time is extended to about 7 seconds, the bacteria are greatly reduced to about 1/300.

According to one example of the heat sterilization apparatus, which is commercially available, it was sterilized buckwheat pressure in the pressure vessel as 1Kg / cm ^2,
The data shows that the number of bacteria 7.5 × 10 ³ before treatment was reduced to 300 or less in a treatment time of 60 seconds, but how much the sterilization effect of the device according to the present invention is even faster in comparison with this Can be increased. This is because when the stirring device 4 is rotated, the pins 4b function as if they are spiral blades and the flour in the container 3b comes into contact with the pins 4b without leaving, so that the stirring is sufficiently performed, and the container 3b This is considered to be the effect that the saturated steam injected into the inside comes into even contact with the flour.

As for the direction of the steam inlet 6, as shown in FIG. 3, a result that the tangential direction (shown by 6b) is higher in the tangential direction (shown by 6b) than the radial direction (shown by 6a) of the container.

In the above embodiment, a pin was used as the stirring blade 4b,
Although it was not necessary to use a pin, it was confirmed that a bar-shaped blade close to a square or a circle showed a higher sterilizing effect than a plate blade having a rectangular cross section. Further, the rod-shaped stirring blade needs to have a transfer function in addition to the stirring function for the powdery granules. For this purpose, not only is it arranged spirally around the rotation axis as in the embodiment, but also, Other arrangements may be used as long as the rotation trajectories are arranged with almost no gap.

When the internal pressure is high, a high-pressure gas (saturated water vapor in this case) escapes in the seal using a rotary valve. However, in the case of saturated water vapor, the vapor condenses and solidifies the powder and granules, making it impossible to operate. This tendency is particularly strong for the supply of the granular material to the pressure vessel 3b. On the other hand, when a material seal screw is used, not only does the internal water vapor not leak, but also such a disadvantage does not occur as a result of the seal portion being rubbed with a new powder having a low moisture content.

In addition, since the heat-treated granular material has more moisture than the raw granular material, the moisture is adjusted through a drying process.
Flash drying is used for this drying.

(Effects of the Invention) As described above, in the present invention, a plurality of rod-shaped blades are arranged such that the rotation trajectories viewed from the direction perpendicular to the rotation axis are arranged with almost no gap under pressure on the granular material. As a result, the powder is mixed with the saturated steam and heated sufficiently, so that a high sterilizing effect can be obtained in a short time.

On the other hand, the water vapor used for heating becomes water and is added to the granules, but at this time, it is uniformly added without forming clumps or blocks due to the effect of stirring. Therefore, smooth continuous operation can be performed without the function becoming dirty.

[Brief description of the drawings]

1 (a) and 1 (b) are a schematic side view and an end view of an embodiment of the apparatus for sterilizing a granular material according to the present invention, FIG. 2 is a development view of a stirring blade, and FIG. 3 is a pressure vessel. FIG. 3 is a diagram showing a position of a steam inlet with respect to FIG. 1 ... hopper, 2 ... material seal screw,
3 ... Mixer, 3a ... Inlet, 3b ... Pressure vessel, 3c ...
... Outlet, 4 ... Stirring device, 4a ... Rotary shaft, 4b ... Pin

Claims (2)

(57) [Claims] 1. A cylindrical pressure vessel having a powder inlet near one end, a powder outlet near the other end, and having a saturated steam inlet, and a pressure vessel inside the pressure vessel. Stirring means for stirring and transferring the granular material input from the input port toward the discharge port while stirring, the stirring means including a plurality of rod-shaped blades having a size close to the inner diameter of the cylinder on the rotating shaft. Characterized by being arranged so that the rotation trajectories of the rod-shaped blades, which are helically implanted around the circumference and viewed from a direction perpendicular to the rotation axis, are arranged in the axial direction of the rotation axis with almost no gap. Sterilizer. 2. The apparatus for sterilizing powder and granular material according to claim 1, wherein the powder and granular material before sterilization is supplied to the powder and granular material inlet of the pressure vessel via a material seal screw.