JPH0716396B2 - Method and apparatus for controlling tank temperature - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for controlling the temperature of an apparatus that requires highly accurate temperature control such as a culture tank. The present invention also provides a device suitable for high-accuracy temperature control, and a temperature suitable for application to a so-called "multipurpose batch plant" for high-mix low-volume production in which several tanks having different capacities are switched and used. Regarding control device.

[Prior art]

Tanks used in the field of biotechnology, such as tanks for fermentation and cell culture, require highly accurate temperature control. In addition to the requirement for high precision, this type of tank has a problem that the set temperature is close to room temperature and is easily affected by changes in room temperature, and existing technologies cannot handle it. In the conventional tank temperature control method, as shown in FIG. 2, hot water or cold water (hereinafter, represented by hot water) is circulated through heating / cooling means such as the jacket (11) of the tank (1) to heat the tank liquid. When this is done, the temperature of this hot water is raised by the heat exchanger (9), and when cooled, cold water is introduced into and mixed with the hot water to lower the temperature of the hot water and indirectly control the temperature inside the tank. The "cascade method" is generally used. The hot water circulation type cascade control method using a heat exchanger has drawbacks that it takes a long time to reach the set temperature, and if the heating and cooling are performed rapidly, overshoot of the tank temperature is observed. On the other hand, in a factory that intends to perform high-mix low-volume production, multiple tanks with different capacities are prepared and used according to the production volume, but the capacity of the heat exchanger is limited.
A corresponding heat exchanger must be installed in each tank. Since it is rare to use all the tanks at the same time and usually only one is required, it is possible to save the construction cost if only one set of temperature control means can cope with the tanks having different capacities.

SUMMARY OF THE INVENTION A first object of the present invention is to provide a control method capable of controlling temperature of tanks with high accuracy and speed, and an apparatus used for implementing the control method. A second object of the present invention is to provide a temperature control device which is advantageous for a multipurpose batch plant by utilizing this technique.

[Means for Solving the Problems]

The method of controlling the tank temperature of the present invention is a method of controlling the temperature in the tank by circulating hot water as a heat medium through a heating / cooling means provided inside or outside the tank, and steam is heated in hot water during heating. Blow with a water mixer to quickly raise the temperature, and during cooling, mix cold water with hot water to quickly lower the temperature and circulate, and directly add steam or cold water while there is a large difference between the temperature in the tank and the set temperature. Continue to circulate while sending to heating / cooling means, or continuing to blow steam into warm water or mixing cold water, and stop blowing steam or mixing cold water to circulate after the temperature difference falls within a predetermined limit. Continuing with the above, or conversely, by mixing cold water or blowing steam to circulate warm water that has approached the set temperature, the set temperature can be reached in a short time. It can be, characterized in that to achieve high accuracy control to avoid overshoot. An apparatus for controlling the tank temperature according to the present invention for realizing the above method has the following parts as shown in FIG. a) a jacket (11) for heat transfer, a tank (1) equipped with a coil or a baffle, b) a line (2) and a pump (3) for circulating hot water as a heat medium through these heat transfer means, Outbound (2
Air / water mixer (4) provided on the 1) side and return line (2)
2) a hot water temperature control device consisting of a diversion pot provided on the side, c) a steam supply source (8A) and a cold water supply source (8B),
Heating / cooling source (8) consisting of steam drain drainage channel (8D) and cold water reflux channel (8C), and d) The temperature inside the tank is measured and based on the difference between the measured temperature and the set temperature. A controller (7) for operating the hot water temperature control device so as to continue blowing steam into hot water or mixing cold water according to a predetermined program, and switch or adjust the amount. In the figure, symbols (5A, 5B, 5C) are valves for adjusting the amount of steam blown in, the amount of cold water supplied, and the amount of drainage that accompanies it. These valves are preferably control valves, but may be on-off valves. Reference numeral (5D) is an on-off valve for discharging the steam drain, and (5D)
E) is a steam trap. As shown in FIG. 5, the temperature control device of the present invention in which the above-mentioned temperature control method is applied to a multipurpose batch plant has two or more tanks (1
-I, 1-II, 1-III) and the corresponding number of heatings /
Cooling sources (8-I, 8-II, 8-III) are arranged at opposite positions, and one hot water temperature control device (TCM) can move between them and any of the tanks to be used. The corresponding heating / cooling source, (1 in the example shown)
-II) and (8-II) are connected to each other.

[Work]

For example, when the ambient temperature is about 20 ℃, the temperature inside the tank is 50 ℃.
In the case of controlling the temperature of the tank, only steam is introduced into the hot water circulation passage at the time of start-up to apply a large amount of heat to the tank to rapidly raise the temperature. The steam drain generated at this time is discharged to the outside of the system from, for example, the steam trap (5E) provided in the circulation flow path through the steam drain drain flow path (8D). If the contents of the tank are within a certain limit from the heated set temperature (eg a difference of 5 ° C, in this case 45 ° C
(If the above is the case), cold water is put into the circulation passage to lower the temperature inside the jacket, and the pump is operated to continue heating. After that, an appropriate amount of steam or cold water is introduced into the circulating warm water according to the rise and fall of the tank temperature, and the warm water temperature is adjusted to control the tank temperature. The above pattern is as shown in Fig. 3. The rapid temperature rise by steam heating at the time of start-up and the fine adjustment of the circulating hot water temperature make it possible to change the temperature inside the jacket indicated by the thin solid line. Is brought to the temperature in the tank indicated by a thick solid line, the set temperature is reached in a short time, and overshoot can be avoided to perform highly accurate temperature control. In the conventional device having the configuration shown in FIG. 2, since it depends on the hot water temperature control by the indirect heating using the heat exchanger, as shown in FIG. 4, the temperature change in the jacket is gentle and has inertia. Not only does the temperature inside the tank rise slowly, but overshoot is likely to occur. As mentioned above, when using the conventional cascade method,
In order to control the tank temperature of the multipurpose batch plant, a heat exchanger dedicated to each tank had to be provided, but when the present invention is followed, the capacity of the tank can be flexibly adjusted by simply adjusting the introduction amount of steam or cold water. Therefore, one set of hot water temperature control device (TCM) can be used to control the temperature of two or more tanks by switching valves. The apparatus shown in FIG. 5 is an application of this to a multipurpose batch plant in which the tank is fixed and the apparatus relating to the utility is moved to cope with it.

【Example】

Temperature control of two culture tanks with capacities of 300 and 3000 respectively was performed using a set of hot water temperature control device. If you show the amount of steam and cold water used in a steady state to maintain the set temperature of 37 ° C together with the opening of each control valve and the circulating hot water amount,
It is as follows. Both of these temperature controls could be performed with an accuracy within ± 0.1 ° C.

【The invention's effect】

If the temperature of the tank is controlled by the method of the present invention, the time required to reach the set temperature can be shortened, there is almost no danger of overshoot, and highly accurate control is possible. Even if the set temperature is near room temperature, it is less affected by room temperature.
It is useful for temperature control of tanks used in the range of ° C. The device of the present invention is compact and inexpensive to construct. This effect is particularly great when one set of hot water temperature control device is associated with two or more tanks.

[Brief description of drawings]

FIG. 1 is a flow diagram showing the basic configuration of a control device for explaining the method for controlling the tank temperature of the present invention. FIG. 2 is a flow diagram corresponding to FIG. 1 for explaining a conventional tank temperature control technique. FIG. 3 is a conceptual graph showing changes with time in the temperature in the jacket and the temperature in the tank from the start-up to reaching the set temperature, for explaining the effect of the present invention. FIG. 4 is a graph similar to FIG. 3 showing the change in temperature in the prior art. FIG. 5 is a plan view of an apparatus for controlling the tank temperature, showing the case where the present invention is applied to a multipurpose batch plant. In this figure, the hot water temperature control device is shown as a module and its details are omitted. 1,1-I, 1-II, 1-III …… Tank 11 …… Jacket 2 …… Hot water circulation line 21 …… Forward, 22 …… Return 3… Circulation pump 4 …… Steam mixer 5A, 5B , 5C …… Control valve 5D …… Steam drain discharge valve 5E …… Steam trap 6 …… Shunting pot 7 …… Controller 8 …… Heating / cooling source 8A …… Steam supply source 8B …… Cold water supply source 8C …… Cold water return Flow path 8D …… Steam drain drainage flow path 9 …… Heat exchanger TCM …… Hot water temperature control device (module)

Claims (5)

[Claims] 1. A method for controlling the temperature in a tank by circulating hot water as a heat medium through a heating / cooling means provided inside or outside the tank, wherein steam is blown into hot water with a steam-water mixer during heating. Immediately raise the temperature, mix cold water with hot water during cooling, cool the temperature quickly and circulate, and send steam or cold water directly to the heating / cooling means while there is a large difference between the temperature in the tank and the set temperature. , Or continue to circulate while continuing to blow steam into hot water or mixing cold water, and then stop blowing steam or mix cold water to continue circulation after the temperature difference is within a predetermined limit, or vice versa. It is possible to reach the set temperature in a short time by circulating cold water mixed with cold water or blowing steam to bring it close to the set temperature. How to control the tank temperature, characterized in that to achieve high accuracy control to avoid. 2. The method according to claim 1, wherein the temperature in the tank is controlled in the range of 20 to 90 ° C. 3. A device for controlling the temperature of a tank comprising the following parts: a) a tank having a jacket for heat transfer, a coil or a baffle, b) circulating hot water as a heat medium through these heat transfer means. A hot water temperature control device consisting of a line and a pump, a steam mixer provided on the outward side of the line and a diversion pot provided on the return side of the line, c) a steam supply source and a cold water supply source, and a steam drain drainage flow path and A heating / cooling source consisting of a cold water recirculation flow path, and d) measuring the temperature in the tank and blowing steam or hot water into hot water according to a predetermined program based on the difference between the measured temperature and the set temperature. The controller that operates the hot water temperature control device to continue the mixing of La. 4. One for two or more tanks having different capacities.
The device according to claim 3, which is associated with one hot water temperature control device. 5. Two or more tanks having different capacities and a corresponding number of heating / cooling sources are arranged at opposite positions, and one hot water temperature control device is movable between them for use. 5. The apparatus of claim 4 configured to connect between any of the tanks and a corresponding heating / cooling source.