JPH05126451A - Cooling temperature adjusting device - Google Patents

Abstract

PURPOSE:To provide a cooling temperature adjusting device in which increasing in temperature of brine is made fast when a set temperature is changed. CONSTITUTION:A cooling temperature adjusting device is comprised of a control circuit for controlling the temperature of brine flowing in a load 12 at a constant value, a heater 13 to be controlled by the control circuit and a cooling device 1. The heater 13 is controlled in its ON/OFF state at a temperature set by the control circuit. The cooling device 1 is operated when the ON/OFF control is started, and when the heater 13 keeps its on-state continuously for more than a predetermined time, the cooling device 1 is turned off and then the temperature of brine is rapidly increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling and temperature adjusting device for maintaining the load of a plastic molding die or the like at a predetermined temperature by using a cold temperature controlled brine.

[0002]

2. Description of the Related Art As a conventional cooling and temperature controlling apparatus of this type, Japanese Patent Laid-Open No. 1-952 has been proposed by the present applicant.
No. 69 publication is known. This is one in which the evaporator of the cooling device that constitutes the refrigeration cycle is housed in the liquid tank that stores the brine, and the brine is circulated in the brine circulation path in which the cooling temperature is adjusted by the cooling device and the heater and the load is arranged. Is.

[0003]

When the brine temperature is set to a temperature higher than the normal temperature (for example, 40 ° C. or higher), only the heater is first operated so that the brine temperature reaches the set temperature. After that, the cooling device is operated and the heater is turned on / off to keep the brine temperature at the set temperature. However, when the set temperature is changed again and the temperature is set high, the cooling device is set. Has a drawback in that it continues to operate, and it takes a long time to reach the reset temperature.

In view of the above situation, it is an object of the present invention to provide a cooling / controlling device in which the cooling device control means is improved and the time required to reach the set temperature at the time of resetting the temperature is shortened.

[0005]

DISCLOSURE OF THE INVENTION The present invention stores a brine which is supplied to a load through a cooling device which constitutes a refrigeration cycle by connecting a refrigerant compressor, an evaporator and the like, and a brine which is supplied to a load through a brine circulation passage having a circulation pump. A liquid temperature control device that has a liquid tank for storing the evaporator, and the liquid tank contains an evaporator, and a heater is provided in the brine circulation path. , A heater control means for issuing an off command, and a cooling device control for activating the cooling device when the heater control means issues an off signal and stopping the cooling device when the on signal of the heater control means continues for a predetermined time And a control device having means.

[0006]

With the above construction, when the brine temperature is set higher than the normal temperature, the brine is first heated only by the heater to raise the temperature to the set temperature, and the load of the mold or the like is brought to the predetermined temperature. When the brine temperature reaches the target temperature, the cooling device is operated to form a refrigeration cycle, and the evaporator exchanges heat with the heated brine in the liquid tank of the brine storage to lower the temperature. Hereinafter, the heater is turned on and off under the control of the heater control means to adjust the temperature of the brine to maintain a predetermined temperature. Here, when changing the set temperature to a higher set temperature, when it is sensed that the heater has entered for a certain period of time or more, the operation of the cooling device is stopped at that point, and only the heater is heated, thereby changing the predetermined temperature. Will be reached rapidly. After reaching the changed set temperature, the cooling device is operated and the heater is turned on and off in the same manner as described above to maintain the predetermined temperature.

[0007]

The present invention will be described below with reference to the drawings of the embodiments.

FIG. 1 is a schematic view of a cooling and temperature control apparatus, in which reference numeral 1 denotes a refrigerant compressor 2 through a condenser 3, a drier 4, an evaporator 5 wound in a coil shape, and an accumulator 6.
Is a cooling device constituting a refrigeration cycle. The evaporator 5 is a liquid tank 7 with an open upper part for storing the brine a.
It is housed in the upper brine chamber 7A. The brine circulation passage 10 is provided at the outlet 7c at one end of the lower brine chamber 7B through the partition plate 9 having the liquid passage port 8 at the lower end of the upper brine chamber 7A.
, A circulation pump 11 and a load 12 such as a mold are sequentially arranged in the brine circulation passage 10, and an upper return pipe 10a having a branched end is connected to the first inlet 7a of the upper brine chamber 7A.
In addition, a circulation path connecting the lower return pipe 10b to the second inlet 7b of the lower brine chamber 7B is formed, and the brine temperature adjusting heater 13 and the front side of the brine temperature adjusting heater 13 are provided at the position of the return pipe 10c of the brine circulation passage 10. The temperature sensor 14 is arranged at the position. The heater 13, the temperature sensor 14, the fan 15 and the compressor 2 arranged on the front surface of the condenser 5 are connected to the control device 16 for drive control. 1
Reference numeral 7 is a resistor provided in the lower return conduit 10b.
Reference numerals 18 and 19 are manual valves arranged at the front and rear positions of the load 12, 20 is a manual valve for draining the circulation pump 11, and 21 is a manual valve for draining the liquid tank 7.

To explain this action, when the load 12 of, for example, a plastic molding die installed at a position distant from the main body of the above-mentioned temperature control device is heated to a predetermined temperature,
First, the operation switch 22 (see the electric circuit of the control device in FIG. 2) is turned on and the heater 13 arranged in the brine circulation path 10 is connected.
The brine (water or liquid) a flowing through the circulation pump 11 is heated and circulated while being heated, and the temperature is raised to a preset target temperature all at once. At this time, the cooling device 1 side is kept in a non-operating state to accelerate heating of the heater 13 so that the target temperature is reached early (see the operation waveform diagram of FIG. 3).

When the temperature sensor 14 detects that the brine a has reached a predetermined temperature (OFF set value), the heater 13 is turned off via the control device 16 and the operation of the cooling device 1 is started. That is, when the cooling device 1 having the refrigeration cycle performs a predetermined operation, the surrounding brine a is cooled by cooling by evaporation of the refrigerant flowing in the evaporator 5 housed in the upper brine chamber 7A in the liquid tank 7, By lowering the temperature of the brine a, inserting the heater 13 reaching the ON set value, and repeating this operation, the temperature of the load 12 is maintained constant. However, in this case, the cooling device 1 which has started the operation continues to operate, and the temperature is adjusted only by turning on / off the heater 13.

After that, when the set temperature is changed to a high value (for example, the set temperature is changed from 50 ° C. to 60 ° C.),
Since the temperature rise is slow when the cooling device 1 is still operating, the operation of the cooling device 1 is once stopped, and the brine a is rapidly raised to the changed target temperature only by heating the heater 13 as in the initial operation. The following is to maintain the predetermined temperature by repeating the driving of the cooling device 1 and the ON / OFF of the heater 13 as described above.

The control for operating the cooling device 1 and the heater 13 will now be described in detail with reference to the electric circuit shown in FIG. This control circuit is roughly classified into a DC constant voltage circuit 23, a heater control circuit 24, and a cooling device control circuit 25.
And an automatic stop circuit 26.

That is, first, when the operation switch 22 is turned on, the heater control circuit 24 is watching the brine temperature with the temperature sensor 14 of the thermistor located in the brine circulation path 10. However, since the temperature is low at first, this resistance value is High, this potential is low Comparator 2 with temperature sensor 14 connected at one end
A high output is obtained as the output of 7. That is, since the output of "H" is produced, the transistor 28 becomes conductive, the contact 29a of the first relay 29 enters, and the heater 13 is energized. Here, the temperature of the brine a is raised by the heater 13. When the brine temperature reaches the set temperature, the power is turned off and the cooling device 1 is operated. The on / off set value in this case is the variable resistor 3
Adjust at 0. Here, when the temperature sensor 14 detects a predetermined temperature and the resistance value of the temperature sensor 14 becomes small and the − potential of the comparator 27 rises higher than the + potential, the comparator 27 inverts and the comparator 27 The output of 27 becomes "L", a signal is input to the R input of the RS flip-prop 31 that becomes a logic circuit, the output Q becomes "H", and the contact 33a of the relay 33 that drives the compressor 2 and the fan 15 operates. Then, the cooling device 1 operates, and at this time, the first relay 29 is disconnected. However, at the moment when the operation switch 22 is turned on, the output of the flip prop 31 of the cooling device control circuit 25 automatically becomes "L", the transistor 32 turns off, and the relay 33
Does not conduct, the contact 33a opens and the compressor 2 and the fan 1
5 is stopped. Further, the initial setting circuit 34 inverts the output at a constant time (for example, 0.5 seconds) by the time constant circuit of the capacitor 35 and the resistor 36, and sets the set input to "H". After that, the brine temperature exceeds the set temperature and the comparator 2
When 7 issues the first OFF command (“L” output), the reset input becomes “L” and the output Q is inverted to “H”. Therefore, the transistor 32 is turned on, and the compressor 2 and the fan 15 are energized via the relay 30.

Here, the set temperature is variable resistor 30.
When the output of the comparator 27 continues to be “H” due to a sudden change of the load 12 (for example, about 3
When the potential of the capacitor 38 rises and exceeds the reference voltage of the comparator 39 due to the time constant circuit of the resistor 37 and the capacitor 38 of the automatic stop circuit 26, the output of the comparator 39 becomes "L" level and the flip-flop. The "L" signal is input to the S input of 31, the output Q is maintained at the "L" level, the relay 33 is stopped, and the compressor 2 and the fan 15 are stopped. When the output of the comparator 27 does not continue to be "H" or "L" for a certain time, when the output of the comparator 27 is "L", the capacitor 3
The potential of 8 is discharged through the resistor 40 and the diode 41. That is, when the set temperature is changed, the cooling device 1
The heating of the heater 13 rises faster because the operation of
The brine temperature can be changed to the set temperature in a short time, and when the set temperature is reached, the cooling device 1 is operated in the same manner as described above, and the heater 13 is repeatedly turned on and off as appropriate to maintain the brine temperature for the load 12 constant. Let

[0015]

As described above, the cooling and temperature controlling apparatus of the present invention turns off the cooling device when the set temperature is changed midway or when the load suddenly drops and the heater is on for a predetermined time or longer. As a result, the target temperature can be reached quickly.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a cooling and temperature adjusting apparatus showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram.

FIG. 3 is an operation explanatory diagram showing an operation of a heater and a cooling device and a temperature rise of brine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling device 2 Refrigerant compressor 5 Evaporator 7 Liquid tank 10 Brine circulation path 11 Circulation pump 12 Load 13 Heater 14 Temperature sensor 16 Control device

Claims (1)

[Claims] 1. A cooling device that constitutes a refrigeration cycle by connecting a refrigerant compressor, an evaporator, and the like, and a liquid tank that stores brine to be supplied to a load through a brine circulation path having a circulation pump, In a cooling and temperature adjusting device in which an evaporator is accommodated in the liquid tank and a heater is provided in the brine circulation passage, a heater control means for comparing the brine temperature in the brine circulation passage with a set temperature and issuing an ON / OFF command to the heater. And a cooling device control means for activating the cooling device when the heater control means issues an off signal and stopping the cooling device when the on signal of the heater control means continues for a predetermined time. Cooling and temperature control device characterized in that