JPH01148180A - Continuous sterilization apparatus - Google Patents

Abstract

PURPOSE:To perform continuous sterilization of a liquid culture medium, by directly contacting a liquid medium with high-pressure steam under transportation to instantaneously heat the medium at a prescribed temperature and transferring the medium while keeping the heated state for prescribed period, thereby enabling the high-temperature treatment of the medium in a short time. CONSTITUTION:The objective continuous sterilization apparatus 1 has the following construction. The apparatus is furnished with a steam heating sterilizing tank (steam mixer 4), a flow channel 5 for briefly keeping a liquid medium heated in the tank and a flow channel (the 1st heat-exchanger 6 and the 2nd heat-exchanger 7) to cool the medium to a prescribed temperature by heat- exchange. These components are positioned on a flow channel (b) for transferring the liquid medium from a liquid medium supplying part (the medium tank 2 and a feed pump 3) to a culture tank or a temporary storage tank of the medium. The sterilization tank 4 is connected with a steam supplying part [steam-feeding pipe (a)] furnished with a feeding rate controlling means (temperature detectors 52, 53; temperature regulator 8 and an electromagnetic valve 42 for temperature regulation). A steam-feeding port (a filter 41) is attached to the inner bottom part of the tank or thereabout.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a continuous sterilizer. More specifically, the present invention relates to a continuous sterilization device suitable for continuous culture.

(b) Prior Art In order to sterilize a liquid culture medium, it is necessary to hold it at a predetermined high temperature for a predetermined period of time. In the case of fermentation of microorganisms, etc., as a method of continuously sterilizing the liquid medium for fermentation supplied to the fermenter, the medium supply pipe line disposed from the medium supply tank to the fermenter has a double pipe structure, By transferring the culture medium to the inner pipe line of this pipe line and flowing steam to the outer pipe line, the culture medium is subjected to heat treatment and sterilized while being transferred through the pipe line.

In such a case, continuous sterilization can be achieved, for example, by holding the medium transferred through the pipe at a temperature of at least 120° C. for 10 minutes.

(c) Problems to be Solved by the Invention However, the above method requires time for heating and may cause uneven temperature distribution of the culture medium. This is especially true if the culture medium contains sugars and is kept at high temperatures for a long period of time, causing coupling and deterioration of the culture medium.

The present invention has been made in view of this situation, and an object thereof is to provide a continuous sterilization device that can continuously sterilize a culture medium by subjecting it to high temperature treatment in a short period of time.

(d) Means for Solving the Problems Thus, according to the present invention, a steam heating sterilization tank and a liquid heated therein are provided on the flow path for transferring the liquid medium from the liquid medium supply section to the culture tank or medium temporary storage tank. A flow path for holding the culture medium for a short time and a flow path for cooling the culture medium to a predetermined temperature by heat exchange are interposed, and the sterilization tank is connected to a steam supply section equipped with a supply amount adjusting means, and the tank A continuous sterilizer is provided having a steam supply port near the inner bottom.

This invention directly and continuously heats the liquid culture medium to a predetermined temperature by bringing it into direct contact with high-pressure steam during transfer, and maintains this heated state for a predetermined period of time before transfer. The apparatus is characterized in that it is configured so that it can be sterilized.

The liquid medium supply section used in the apparatus of the present invention is suitably composed of a liquid medium supply section and a liquid sending pump that sends the liquid medium to the flow path. The liquid feeding pump may be any pump such as a peristaltic pump or a plunger pump.

The steam heating sterilization tank used in the apparatus of the present invention is comprised of a culture medium storage part having an introduction path and a discharge path connectable to a liquid culture medium transfer channel, and a steam supply part connected to the medium storage part. The steam supply section is composed of a steam generator and a steam introduction pipe connected from the steam generator to the medium storage section via a supply amount adjusting means and further arranged to open near the inner bottom of the storage section. suitable. A normal throttle valve or the like may be used as the supply amount adjusting means.

Furthermore, this supply amount adjusting means may be attached with a temperature controller capable of operating the above-mentioned means according to the temperature state of the heated liquid medium. It is preferable that the steam introduction pipe is provided with a filter or the like that can remove impurities such as oil normally contained in the generated steam. Regarding these matters, reference will be made to the description of the examples described later. It is preferable that the heat sterilization tank is made of a heat insulating member. The temperature of the steam introduced by the steam introduction pipe is such that the temperature of the steam introduced by the steam introduction pipe is at least 14
The temperature is set to a high temperature that can be heated to 0°C or higher.

In the apparatus of the present invention, the channel that holds the heated liquid medium for a short time means a channel that can maintain the temperature of the liquid medium heated in the steam heating sterilization tank for a predetermined period of time and transfer it. Therefore, the flow path may be, for example, a conduit connected to the steam heating sterilization tank and constructed of several kinds of heat insulating members over a predetermined distance. The predetermined distance is suitably a distance that can last for at least 4 seconds when the temperature of the liquid medium to be heated is about 140° C. as described above, and is appropriately set according to the flow rate of the liquid medium. In addition, examples of the adiabatic structure include configuring the flow path with a heat insulating member. Examples of the material include glass wool and 6 rods, with glass wool being preferred.

The cooling channel provided in the apparatus of the present invention includes a channel for transferring the heated liquid culture medium transferred from the heating holding channel, and a cooling section connected to this channel for heat exchange. It is suitable to have an internal pipe for passing high-temperature fluid, an inlet pipe and a discharge pipe, and an external pipe for cooling water to flow in contact with the outside of the internal pipe. A conventional heat exchanger consisting of a double tube structure with a tube is suitable. In view of the cooling effect, the cooling channel may be configured by piping a plurality of heat exchangers as described above in series.

(E) Effect According to the present invention, the liquid medium introduced from the liquid medium supply section into the heat sterilization tank is brought into direct contact with the high pressure steam supplied here in the tank and instantly stirred to a predetermined high temperature.・Heated. Even when this heated liquid medium is discharged from the tank, it is maintained at that temperature for a predetermined short period of time and is then transferred, and then cooled to a predetermined temperature as it is transferred through a heat exchange cooling channel. , and transferred to a culture tank or medium temporary storage tank.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereby.

(F) Embodiment FIG. 1 is an explanatory diagram of the configuration of an example of the continuous sterilization apparatus of the present invention. Several times, the continuous sterilizer (1) has a culture medium tank (2), a liquid feeding pump (3), a washing pump (3゛),
A steam mixer (4) for directly mixing the medium and steam, a holding header (5) for maintaining the medium at a constant high temperature, a first heat exchanger (6) for cooling the high temperature medium to a low temperature, A second heat exchanger (7) that further cools the medium cooled by the heat exchanger (6) to a predetermined temperature ζ
, a temperature controller (8) for regulating the temperature of the medium entering the holding header (5), and a continuous sterilizer (
1) It mainly consists of a cleaning liquid supply tank (9) for internal cleaning.

The steam mixer (4) includes a culture medium storage section having a medium introduction path and a discharge path, and a steam introduction pipe that opens into the inner bottom of the storage section. The steam introduction pipe includes a filter section (41) and a temperature control solenoid valve (42).
A steam supply pipe (a) which is connected to a steam generator (not shown) is connected in this order.

The holding header (5) is attached to the steam mixer (
It is composed of a pipe body that has a flow path section (51) connected to the culture medium discharge path of 4) and is connected to the first heat exchanger (6). This holding header (5) is made of stainless steel with an inner diameter of 5 hm, and the flow path section (51) is approximately 14 mm in diameter.
The length is set to 0mm. At the time of 250 e/hr, the holding header (5) is connected to the steam mixer (4) and downstream of the flow path section (51).
Temperature detection units (52) and (53) are set.

Both the first heat exchanger (6) and the second heat exchanger (7) have an internal pipe line for passing high-temperature fluid, an inlet pipe, and a discharge pipe, and contact flow of cooling water to the outside of the internal pipe line. A conventional double pipe structure with a cooling water pipe that can be used is used. In addition, the first heat exchanger (6) has a temperature of 250 to 300 (
The temperature of the high temperature fluid introduced at a flow rate of 2/hr is 140°C.
If so, it is designed to have a heat exchange capacity capable of cooling it to 80° C. and discharging it from the internal conduit. On the other hand, when the second heat exchanger (7) contacts and flows cooling water at 25°C, if the temperature of the high-temperature fluid introduced into the internal pipe line at a flow rate of 250 to 30G (/hr) is 80°C, this It is configured to have a heat exchange capacity i that can cool the water to 40° C. and discharge it from the internal pipe line.

The temperature controller (8) is electrically connected to the temperature detection section (52 x 53) of the holding header (5) and a temperature control solenoid valve (42) set in the steam supply pipe (a), and is The temperature control solenoid valve (42) is operated based on the signals output from the detection units (52) and (53), and the amount of steam introduced into the steam mixer (4) is adjusted to adjust the temperature of the heated culture medium. It is configured so that it can be adjusted.

The above steam mixer (4), holding header (5)
), the first heat exchanger (6), and the second heat exchanger (7) are connected in this order through pipe lines to constitute a sterilized medium supply path (b). Note that this sterilized medium supply path (b) extends from the second heat exchanger (7) to a fermentation tank (not shown).

On the other hand, the culture medium supply line (c) is a pipe connected to the introduction pipe of the cooling water pipe of the first heat exchanger (6) through the culture medium tank (2) and the liquid sending pump (3) in this order. It consists of a pipe (Cυ) and a pipe (C3) connected from the discharge pipe of the cooling water pipe to the culture medium introduction pipe of the steam mixer (4).

In the figure, (9) is a cleaning tank, (dX4) is a pure water supply path, and (v, Xv-Xv4Xvs) is a solenoid valve. Further, the washing pump (3°) is stopped during the sterilization process, and in this stopped state, the flow path is maintained in an open state and the culture medium supply pipe (c) is opened. In addition, when cleaning after sterilization, this pump (3°) is activated to allow the medium supply pipe (
A cleaning liquid (pure water) is sent to a).

In the above continuous sterilizer (1), during the sterilization operation, the cleaning pump (3°) is first set to the flow path open state, and the temperature of the steam passing through the filter part (41) of the steam supply pipe (a) is adjusted. The temperature of the culture medium passing through the holding header (5) is adjusted to 145°C using a temperature controller (8) so as to be maintained at 140°C.

In the continuous sterilizer (1) configured as above,
For example, a liquid medium containing 10% glucose, 1% polypeptone, and 1% yeast extract is maintained at 25°C and prepared in the medium tank (2), and the liquid feed rate of the liquid pump (3) is set to 250 to 30012. /hr. If the liquid medium is sent by the liquid sending pump (3) under these conditions, the medium transferred through the medium supply pipe (Cυ) will pass through the medium supply pipe (Cυ) through the first heat exchanger (6). C8) is further transferred and introduced into the steam mixer (4). Steam adjusted to 145°C is directly bubbled into the culture medium in the steam mixer (4), and as a result, the culture medium is instantly heated. The high temperature culture medium heated to about 140°C is transferred from the steam mixer (4) to the holding header (5). It is transferred inside the holding header (5). During this period, the high-temperature medium is insulated from the outside and the high-temperature state is maintained for a predetermined period of time (in this case, about 4 samples).
After being held and thus subjected to sterilization treatment, it is introduced into the first heat exchanger (6). In addition, the culture medium transferred inside the holding header (5) has two temperature detectors (5).
2X53), and if the temperature detected by any of the detectors is lower than a predetermined temperature (about 140°C in this case), this signal is output to the temperature controller (8) and the corresponding The temperature controller (8) operates the temperature regulating solenoid valve (42) of the steam supply pipe (a) and introduces the steam into the steam mixer (4) so that the temperature detected by the temperature detector becomes a predetermined temperature. Adjust the amount of steam produced.

The high temperature (140°C) introduced into the first heat exchanger (6)
The culture medium is heat exchanged with cooling water (in this case, the culture medium at 25°C), cooled to a predetermined temperature (80°C in this case), and discharged from the heat exchanger. The medium discharged from the heat exchanger (6) is further introduced into the second heat exchanger (7), cooled to a predetermined temperature (40° C. in this case), and supplied to the fermenter.

Through the above operations, the medium supplied to the fermenter is continuously sterilized during transfer. Furthermore, since this sterilization treatment is carried out in a short time, continuous sterilization can be performed without causing coupling of sugars in the medium components.

When the supply of the medium is finished, the solenoid valve (vI) (v3)
(V, Xv,) and the cleaning pump (3
) into the medium supply path (C), the sterilized medium supply path (
b) Washing water is supplied into the interior to wash them, and pure water is further supplied through a pure water supply pipe (dXf) in preparation for the next sterilization process.

(G) Effects of the Invention According to the present invention, a culture medium can be continuously sterilized by high temperature treatment in a short time. Since the medium is heated instantly and uniformly,
Deterioration of the medium due to coupling etc. can be prevented. Because of the direct heating method, the heating means can be made small-scale and the cost can be reduced.

In addition, it has good thermal efficiency, so running costs are low.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an example of the continuous sterilization apparatus of the present invention. (2)・・・・・・Culture tank, (3)・・・Liquid pump, (4)・・・Steam mixer, (5)・・・Holding header, ( 6)...
...First heat exchanger, (7)...Second heat exchanger, (8)...Temperature controller, (9)...
...Washing tank, (41)...Filter section, (42)...Temperature adjustment solenoid valve, (51)...
...Flow path section, (52) (53)...
Temperature detection unit, (a)...Steam supply pipe, (b)...Sterilized medium supply path, (c)...Medium supply path, (Cυ(C8)・... Culture medium supply conduit, (d) (
4)...Pure water supply path.

Claims (1)

[Scope of Claims] 1. A steam heating sterilization tank, a flow path for holding the heated liquid medium there for a short time, and a predetermined channel on the flow path for transferring the liquid medium from the liquid medium supply section to the culture tank or medium temporary storage tank. The sterilization tank is provided with a flow path for cooling by heat exchange to a temperature, and the sterilization tank is provided with a steam supply section equipped with a supply amount adjusting means, and a steam supply port is provided near the bottom of the tank. A continuous sterilizer.