JP2743073B2 - Temperature control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for a system that controls a supply amount of a heat source or turns a heat source on and off to control a temperature of a control target. The present invention relates to a temperature control device suitable for safely and optimally lowering or raising the temperature to a target temperature in a shortest time.

[Prior Art] A conventional temperature control method is, as described in Japanese Patent Application Laid-Open No. 54-67872, a heater in a temperature control system for turning on / off a heat source of a heater to raise the temperature of a temperature control target to a target temperature. In order to avoid the occurrence of stress due to thermal imbalance between the unit and the control target unit, the temperatures of the heater unit and the control target unit are respectively detected, and the temperature difference between the detected heater unit temperature and the control target unit is predetermined. When the temperature difference is larger than the tolerance value, the heater is turned on, and when the temperature difference is larger than the tolerance value, the heater is turned off, and the temperature of the control target portion is raised to the target value so that the temperature difference does not exceed the tolerance value. I was

[Problems to be Solved by the Invention] The above-mentioned prior art considers the thermal stress generated when the temperature of the control target is raised to the target value, but does not consider the thermal stress generated when the temperature is lowered. .

Therefore, when the temperature of a controlled object that causes thermal stress due to a partial increase or decrease in temperature is increased due to a complicated or large structure of the device, there is a risk that the device may be damaged by the thermal stress. At the same time, there has been a problem that operating reliability is reduced due to thermal fatigue and the like.

Further, the conventional heating (falling) control method has the following problems.

(1) This control method takes into account only the temperature difference between the heater section of one block and the control target section, and when applied to control of a plurality of heaters, a temperature difference may occur between control points. However, it is not suitable for controlling a plurality of heaters.

(2) Since the heater is turned off when the temperature difference between the heater section and the control target section becomes larger than a predetermined tolerance value, the temperature of the heater section temporarily drops, so that the temperature rises to the target temperature (temperature lowering) ) The time is long and good controllability cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control device capable of adjusting a supply amount of a heat source or turning a heat source on and off to safely and optimally lower or raise the temperature of a control target to a target temperature in a shortest time.

Means for Solving the Problems In order to achieve the above object, the present invention provides a temperature control device for a system that controls the temperature of a control target by adjusting the amount of heat supplied from a heat source or turning the heat source on and off. Means for detecting the temperature of a plurality of predetermined control points of the control object, means for selecting the highest temperature value and the lowest temperature value from the temperature of each part,
When the temperature difference between the maximum temperature and the minimum temperature is equal to or greater than a predetermined allowable value, the minimum value is temporarily fixed as a temperature control target value, and the temperature reduction control of other control points is continued, and then the temperature difference is reduced. Means for setting the temperature control target value lower when the temperature becomes equal to or less than a predetermined value and performing stepwise temperature reduction control.

In order to achieve the above object, the present invention also provides a temperature control device for controlling a temperature of a control target by adjusting a heat supply amount from a heat source or turning a heat source on and off, wherein a predetermined control target is controlled. Means for detecting the temperature of the plurality of control points,
Means for selecting a maximum temperature value and a minimum temperature value from the temperature of each part, and when the temperature difference between the maximum temperature and the minimum temperature exceeds a predetermined allowable value, temporarily sets the maximum value to a temperature control target value. Means for setting the temperature control target value higher when the temperature difference becomes equal to or less than a predetermined value, and controlling the temperature in a stepwise manner. A control device is proposed.

[Operation] In the present invention, when controlling the temperature drop while adjusting the supply amount of the heat source, as shown in FIG. 2, the maximum value (Tmax) and the minimum value (Tmin) of the plurality of temperature detection signals of the temperature control target are determined. When the temperature difference (ΔT) becomes equal to or greater than a predetermined temperature difference allowable value (ΔTp), the minimum value (Tmin) is temporarily fixed as a control set value to perform control. To continue. Next, when the temperature difference (ΔT) becomes smaller than a predetermined value (ΔTs), the temperature control set value is switched to the target value, the temperature lowering control is continued, and the temperature is lowered stepwise. Therefore, the temperature difference of each part to be controlled does not exceed the allowable value.

In the present invention, when performing the temperature increase control while adjusting the supply amount of the heat source, as shown in FIG. 4, the difference between the minimum value (Tmin) and the maximum value (Tmax) of the plurality of temperature detection signals of the temperature control target. (ΔT) is obtained, and when the temperature difference (ΔT) becomes equal to or greater than a predetermined temperature difference allowable value (ΔTp), the maximum value (Tmax) is temporarily fixed as a control set value and control is continued. I do. Next, when the temperature difference (ΔT) becomes smaller than a predetermined value (ΔTs), the temperature control set value is switched to the target value, the temperature raising control is continued, and the temperature is raised stepwise. As a result, a plurality of control points can be more efficiently heated.

On the other hand, in the method of controlling the temperature while turning on / off the heat source, a difference (ΔT) between the maximum value (Tmax) and the minimum value (Tmin) of the plurality of temperature detection signals to be temperature-controlled is obtained, and this temperature difference (Δ
When T) is equal to or greater than a predetermined temperature difference allowable value (ΔTp), the minimum value (Tmin) is temporarily fixed as a control set value, and heat to a control point that has dropped to the control lower limit set value is applied to the control point. While controlling the supply amount within a minute control range with the set value as a lower limit, the control waits for another control point to cool down. Next, when the temperature difference (ΔT) becomes smaller than a predetermined value (ΔTs), the temperature control set value is switched to the target value, the temperature lowering control is continued, and the temperature is lowered stepwise. As for the control point whose temperature has fallen to the control lower limit set value, while turning on and off within a minute control range having the lower limit of the set value, it waits for other control points to cool down. Does not exceed the allowable value, and the temperature can be efficiently lowered at an optimum temperature lowering rate.

The same applies to the case of controlling the temperature rise while turning the heat source on and off.

[Embodiment] With reference to FIG. 1 and FIG. 2, an embodiment of a temperature control device for controlling the temperature drop by adjusting the electric energy of the electric heater according to the present invention will be described.

The temperature control target 1 is heated by a plurality of heaters 2, and the temperature of each part is detected by a plurality of temperature detectors 3 arranged at the heater and at a predetermined position of the control target. The power supplied to the heater 2 is adjusted by a power controller 8 of a power control panel 6 according to a power control signal 5 from a temperature controller 11.

The power control signal 5 is a control signal that is output from the power calculation circuit 14 and that makes the deviation signal 33 between the temperature detection signal 4 and the temperature control setting signal 32 zero. Is output to the controller 8 under the AND condition.

The high selector 19 and the low selector 24 output the temperature detection signal 4
The maximum value (Tmax) 34 and the minimum value (Tmin) 36 are obtained, and then the temperature difference signal (Tmax-Tmin) 37 is obtained by the subtractor 18. The temperature difference signal 37 is input to the monitor relays 22 and 23.
When the temperature difference exceeds the allowable value (ΔTp), the switching signal 39 for fixing the minimum value is output. Also, monitor relay 23
Outputs a switching signal 40 for further lowering the target temperature when the temperature difference signal 37 becomes equal to or less than a predetermined value (ΔTs).

The operation switching circuit 20 temporarily stores the lowest value 36 when the switching signal 39 is input, and outputs the lowest value 36 as the temperature setting signal 32. When the switching signal 40 is input, the signal generator 21
And outputs the target temperature signal 38 as the temperature setting signal 32.

If the temperature difference signal 37 exceeds the alarm set value (ΔTA), this is detected by the monitor relay 25 and the alarm
Output to 26 to notify the operator.

According to the present embodiment, it is possible to efficiently lower the temperature to the target temperature so that the temperature difference of each part of the control target 1 does not exceed a predetermined tolerance value (ΔTp). Also, even in the event that the alarm value exceeds the alarm set value (ΔTA), the operator can quickly respond, and the safety is further improved.

Referring to FIGS. 3 and 4, an embodiment of a temperature control device for controlling the temperature rise by adjusting the amount of electricity of the electric heater according to the present invention will be described.

Control target 1, heater 2, temperature detector 3, and power control panel 6
Is the same as that of the embodiment shown in FIG.

The power control signal 5 is a control signal that is output from the power control circuit 14 and that makes the deviation signal 33 between the temperature detection signal 4 and the temperature setting signal 32 zero. Is output to the controller 8 under the AND condition.

The high selector 19 and the low selector 24 output the temperature detection signal 4
The maximum value (Tmax) 34 and the minimum value (Tmin) 36 are obtained, and then the temperature difference signal (Tmax-Tmin) 37 is obtained by the subtractor 18. The temperature difference signal (Tmax-Tmin) 37 is input to the monitor relays 22 and 23. The monitor relay 22 outputs the maximum value when the temperature difference signal 37 becomes equal to or more than the allowable value (ΔTp) of the temperature difference of the control target 1. And outputs a switching signal 39 for fixing. Also,
When the temperature difference signal 37 becomes equal to or less than a predetermined value (ΔTs), the monitor relay 23 outputs a switching signal 40 for increasing the target temperature. The operation switching circuit 20 temporarily stores the maximum value 34 when the switching signal 39 is input, and outputs the temperature setting signal
Output as 32. When the switching signal 40 is input,
The target temperature signal 38 from the signal generator 21 is output as a temperature setting signal.

According to the present embodiment, it is possible to efficiently raise the temperature to the target temperature so that the temperature difference of each part of the control target 1 does not exceed the predetermined tolerance value (ΔTp).

FIG. 5 is a block diagram showing an example of a temperature control device to which the present invention is applied, in which the power of an electric heater is turned on and off to control the temperature. However, in this example, when the temperature difference between the maximum temperature and the minimum temperature exceeds a predetermined allowable value, the minimum value is not temporarily fixed as the temperature control target value. In FIG. 5, the configurations of the control target 1, the heater 2, and the temperature detector 3 are the same as those in the embodiment of FIG. The power supply to the heater 2 is turned on and off by the temperature control device 11.
Is performed by the switch 9 of the power control panel 6 in accordance with the ON / OFF control signal 60 from the controller. The ON / OFF control signal 60 is a control signal having hysteresis for maintaining and controlling the temperature detection signal 4 within the range between the control lower limit set value 53 and the control upper limit set value 54.
The switch 9 is opened and closed by AND logic with the temperature decrease command signal 31 from the control circuit 12.

The control lower limit setting signal 53 is the highest value of the temperature detection signal 4 (Tm
ax) 34 is obtained by the high selector 19, and then the highest value (Tmax)
The difference between the temperature difference 34 and the allowable value (ΔTp) of the temperature difference of the control target 1 is obtained by the subtractor 18 and the signal (Tmax−ΔT
p). Here, the low limiter 16 sets the temperature lowering target value (T
min). The control upper limit setting signal 54 is a control lower limit setting signal (Tmin) 53 and a predetermined value (ΔTs).
The sum with 56 is obtained by the adder 59. The allowable value (ΔTp) 55 and the predetermined value (ΔTs) 56
These are set by setting circuits 57 and 58, respectively. These setting circuits may be a manual setting device or an arithmetic device for calculating a temperature difference value from allowable thermal stress.

The same control procedure as that of the embodiment in which the power amount of the electric heater is continuously controlled by the power regulator of FIG. 1 can be applied to the method of turning on and off the power of the electric heater in FIG. Maximum value of multiple temperature detection signals (Tma
x) and the minimum value (Tmin) are determined, and when the temperature difference (ΔT) becomes equal to or greater than a predetermined temperature difference allowable value (ΔTp), the minimum value (Tmin) is temporarily determined. Is fixed as the control setting value. While controlling the heat supply amount to the control point whose temperature has fallen to the control lower limit set value within a minute control range for lowering the set value, the control unit waits for another control point to cool down. Next, when the temperature difference (ΔT) becomes smaller than a predetermined value (ΔTs), the temperature control set value is switched to the target value, the temperature lowering control is continued, and the temperature is lowered stepwise. As for the control point whose temperature has fallen to the control lower limit set value, while turning on and off within a minute control range having the lower limit of the set value, it waits for other control points to cool down. Does not exceed the allowable value, and the temperature can be efficiently lowered at an optimum temperature lowering rate.

According to the present embodiment, the control point having a high temperature drop rate is maintained while turning on and off within a minute control range when the temperature is lowered to the control lower limit set value (Tmin) and then the set value is adjusted. The temperature can be reduced more safely and efficiently, that is, in the shortest time at an optimal temperature reduction rate so that the temperature difference between the respective parts of the object 1 does not exceed a predetermined allowable value (ΔTp). In addition, since the allowable value (ΔTp) and the like can be set from the outside, it can be universally applied to various control objects having different thermal characteristics. Further, since the heater power is switched on and off by the switch, a suitable temperature control device can be obtained at low cost.

Although the embodiment shown in FIG. 3 is a heating control method for adjusting the electric power of the heater, the same heating control function can be realized by a method of turning on and off the heater power by a switch as shown in FIG. Is similar to the embodiment of FIG.

The embodiments described so far are all examples of a heating method using a heater. However, the present invention is not limited to a heating method using a heater other than a heater, such as gas, hot water, steam, or the like. Is effective as long as
In particular, it is convenient to apply to a heater for a coolant of a fast breeder reactor, and the thermal stress can be reduced.

As is clear from the comparison of FIGS. 1, 3 and 5, since each embodiment has many common parts, it is possible to switch the temperature control circuit by software and put it to practical use. At that time, the optimum control mode can be selected quickly and easily.

[Effects of the Invention] According to the present invention, it is possible to control the temperature decrease or temperature increase without generating thermal stress due to the temperature difference of each part of the temperature control target, and to reduce the thermal fatigue. The operating reliability is improved and the service life can be extended.

Moreover, since the temperature set value of each part to be controlled is appropriately changed and the temperature is lowered or raised at an optimum rate of change, so-called overshoot or undershoot does not occur.
Temperature control is possible in the shortest time.

It is possible to safely lower or raise the temperature of a wide range of controlled objects having a plurality of control points and improve the function.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a temperature controller for controlling the temperature by adjusting the amount of electric power of an electric heater according to the present invention, and FIG. 2 explains the temperature lowering control characteristics of the temperature controller of FIG. FIG. 3 is a block diagram showing the configuration of an embodiment of a temperature control device for controlling the temperature rise by adjusting the electric energy of the electric heater according to the present invention, and FIG. 4 is a temperature rise control of the temperature control device of FIG. FIG. 5 is a block diagram showing an example of a temperature control device of a type in which the power of an electric heater is turned on and off to control a temperature drop as an object to which the present invention is applied. 1 ... controlled object 2 ... heater 3 ... temperature detector 4
... temperature detection signal, 5 ... power control signal, 6 ... power control panel, 7 ... power bus, 8 ... power regulator, 11 ... temperature control device, 12 ... control circuit, 13 ... subtraction vessel,
14: Power calculation circuit, 15: Gate circuit, 16: Low limiter, 18: Subtractor, 19: High selector, 20: Calculation switching circuit, 21: Signal generator, 22, 23, 25 ... ... Monitor relay, 24 ... Low selector, 26 ...
... Alarm, 31 ... Temperature drop command signal, 32 ... Temperature setting signal, 33 ... Deviation signal, 34 ... Highest value, 36 ... Lowest value, 37 ... Temperature difference signal, 38 ... Target temperature signal, 39, 40: Switching signal, 51: Comparator, 52: AND circuit, 53: Control lower limit setting signal, 54: Control upper limit setting signal, 55: Tolerance value setting signal, 56: Control Range setting signal, 5
7,58 Setting circuit, 59 Adder, 60 ON / OFF control signal, 63 Temperature rise command signal

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshinori Kajiyama 3-2-1 Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi Engineering Co., Ltd. (56) References Real public 1987-32545 (JP, Y2) Real public Akira 63-3661 (JP, Y2) Jikken Sho 63-46073 (JP, Y2) Jigaku 58-20228 (JP, Y2)

Claims (2)

(57) [Claims] 1. A temperature control device for controlling the temperature of a control target by adjusting the amount of heat supplied from a heat source or turning the heat source on and off, detecting temperatures of a plurality of predetermined control points of the control target. Means for selecting a maximum temperature value and a minimum temperature value from the temperatures of the respective parts, and temporarily setting the minimum value when a temperature difference between the maximum temperature and the minimum temperature becomes equal to or greater than a predetermined allowable value. The temperature control target value is fixed and the temperature control of the other control points is continued, and then, when the temperature difference becomes equal to or less than a predetermined value, the temperature control target value is set lower and the temperature control is performed stepwise. A temperature control device. 2. A temperature control apparatus for controlling the temperature of a control target by adjusting the amount of heat supplied from a heat source or turning on / off the heat source, wherein a temperature of a plurality of predetermined control points of the control target is detected. Means for selecting a maximum temperature value and a minimum temperature value from the temperatures of the respective parts, and temporarily storing the maximum value when the temperature difference between the maximum temperature and the minimum temperature becomes equal to or greater than a predetermined allowable value. The temperature control target value is fixed as desired, and the temperature increase control of the other control points is continued, and thereafter, when the temperature difference becomes equal to or less than a predetermined value, the temperature control target value is set higher and gradually increased. And a means for controlling the temperature.