JP2522975B2 - Mold cooling device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling device for a plastic molding die that needs to be maintained at a predetermined temperature higher than room temperature.

<Prior Art> Liquid cooling device in which an evaporator that constitutes a refrigeration cycle together with a refrigerant compressor or the like is arranged in a tank that stores a cooling liquid such as water or brine to cool the cooling liquid in the tank Is disclosed, for example, in Japanese Utility Model Publication No. 60-15107 and is conventionally known. The coolant temperature at which this refrigerant compressor can operate is usually 40 ° C or lower, and if it is higher than this, the superheat of the suction gas of the refrigerant compressor becomes excessive, and the temperature rise of the high pressure gas and the motor winding temperature. The fear of causing an abnormal rise in

<Problems to be Solved by the Invention> When a liquid cooling device using the above refrigeration cycle is used as a cooling device for a plastic molding die, a problem is that the temperature is higher than the operating temperature of the refrigerant compressor. This means that the temperature of the eye coolant may be set. The applicant of the present invention has previously devised a patent application for a mold cooling device shown in FIG. 3 that can be operated without any trouble in such a case, and filed a patent application.

Briefly explaining the mold cooling device shown in FIG. 3, A is a refrigerating cycle refrigerant circuit constituted by connecting the refrigerant compressor 1, the aggregator 2, the dryer 3, the evaporator 4, the accumulator 5 and the like, and 6 is The fan and B are cooling liquid circulation circuits that return the cooling liquid stored in the tank 7 to the tank 7 again via the circulation pump 8 and the mold 9. The inside of the tank 7 is divided into a tank upper chamber 7a and a tank lower chamber 7b by a partition plate 10 having a liquid passage hole 11. An evaporator 4 is provided in the tank upper chamber 7a and a tank lower chamber 7b is provided. Is provided with a heater 12 for adjusting the coolant temperature. The cooling liquid circuit B connects the tank lower chamber 7b and the suction port of the circulation pump 8 by a delivery pipe 13, and particularly the return pipe 14 from the mold 9 is a thin return pipe 14a that is common in the tank upper chamber 7a. And a branch return flow path with a relatively thick return pipe 14b proliferating in the tank lower chamber 7b, and a flow rate adjusting resistor 15 and a return temperature detecting temperature sensor inside the latter return pipe 14b. A temperature signal from the temperature sensor 16 is sent to the control circuit 17 to linearly control the operation of the refrigerant compressor 1 and the on / off time of the heater 12.

In this way, the difference in the pipe diameters of the two return pipes 14a and 14b and the function of the resistor 15 suppress the amount of liquid returning to the tank upper chamber 7a in which the evaporator 4 is provided, and the temperature of the cooling liquid is, for example, 50%. Even if the temperature was as high as 0 ° C, the average temperature of the cooling liquid in the tank upper chamber 7a was lowered to a temperature at which the refrigerant compressor could operate.

However, even in the device shown in FIG. 3, it is inevitable that the operating limit will be exceeded when the coolant temperature is further increased. As described above, in the cooling system using the refrigeration cycle, when the coolant temperature rises, the refrigerant compressor 1 is overloaded and the protector stops, but in the worst case, it fails.
On the other hand, in an air-cooling type or water-cooling type heat exchange device having a different cooling method from the refrigeration cycle, in particular, in an air cooling type heat exchange device, if the temperature difference between the cooling liquid and the room temperature is small, the cooling capacity decreases, The mold temperature cannot be kept constant. In addition, if a refrigeration system and a heat exchange device other than that are installed side by side and manually switched, it is possible to switch arbitrarily, but under the cooling liquid temperature condition where the refrigerant compressor stops, it is used. As a person, I intend to cool it, but actually I have stopped operation,
There is a risk that the mold temperature rises and the molded product becomes defective.

In view of the above situation, the present invention automatically switches between a refrigerating device and a cooling device other than the refrigerating device to control the temperature from a low temperature to a high temperature, and a mold capable of eliminating mistakes during use. The aim is to provide a cooling device.

<Means for Solving Problems> The present invention provides a heat exchanger having a switching device provided in a flow path from a mold to a branch return flow path and having a heat exchanger between the switching device and the branch return flow path. An on-off operation of the refrigerating device depending on whether the coolant temperature is lower than or higher than the set temperature, and a switching device for returning without passing through the heat exchanger or returning through the heat exchanger with a passage for the exchanger An automatic control device that performs switching operation is provided so that the coolant temperature can be used safely from low temperature to high temperature.

<Example> An example according to the present invention is shown in FIG.

In FIG. 1, the same parts and members as those shown in FIG. 3 are given the same reference numerals as those used in FIG. 3 for convenience. By comparing FIG. 1 with FIG. 3, the following points will be understood. That is, the tank 7 for storing the cooling liquid is divided into upper and lower parts by the partition plate 10 having the liquid passage hole 11 and the evaporator 4 of the refrigerating device is provided in the tank upper chamber 7a.
The heater 12 is provided in the tank lower chamber 7b. In the cooling liquid circulation circuit B, only the tank lower chamber 7b is connected to the suction port of the circulation pump 8 by the cooling liquid delivery pipe 13, but the return pipe from the mold 9 is connected.
14 is a branch return flow path between a thin return pipe 14a that grows in the tank upper chamber 7a and a relatively thick return pipe 14 that grows in the tank lower chamber 7b, and inside the relatively thick return pipe 14b A low-antibody 15 for adjusting the flow rate is installed in the tank upper chamber where the evaporator 4 is located.
Returning to 7a is that the flow rate of the cooling liquid is suppressed, and further, there is a temperature sensor 16 for the cooling liquid and a control circuit 17 that operates by the detection signal of the temperature sensor 16 to operate the refrigerant compressor 1 and the heater 12. In terms of controlling on / off, there is no particular difference between the two.

However, in the case of FIG.
In the flow path to a, 14b, it is possible to switch the flow path of the cooling liquid by returning to the two directions shown by arrow a and arrow b, for example, by providing a switching device 18 such as a three-way solenoid valve, When flowing in the same direction, it is returned to the tank upper chamber 7a and the tank lower chamber 7b in the same manner as described above. But,
When flowing in the direction of arrow B, the flow path 2 of the heat exchanger 19 which is separated from the switching device 18 and has the branch return flow paths 14a and 14b in common.
After flowing to 0, it is finally returned to the tank upper chamber 7a and the tank lower chamber 7b. The heat exchanger 19 may be air-cooled or water-cooled, but in the case of the air-cooled type, the fan 6 can be shared by arranging it side by side with the condenser 2.
As shown in the figure, by mounting the bypass pipe 21 provided with the resistor 22 in the pipe, the flow rate of the cooling liquid passing through the heat exchanger 19, that is, the heat exchange heat amount can be adjusted.

Further, in the case of FIG. 1, an automatic control device TH such as a thermostat is provided. FIG. 2 shows a circuit example including the automatic control device TH. In FIG. 2, when the switch SW is turned on, the electric circuits of the motor FM of the fan 6 and the motor PM of the circulation pump 8 are closed circuits. However, regarding the motor CM of the refrigerant compressor 1 and the solenoid valve V of the switching device 18, Is an automatic control device TH at about 50 ° C, which usually burdens the refrigerant compressor 1.
When the temperature of the cooling liquid is lower than the set temperature of, the automatic control device TH operates to turn on the contact of CM and turn off the contact of V, thereby driving the refrigerating device and cooling liquid. The switching device 18 is switched to a state in which the heat is returned without passing through the heat exchanger 19. On the contrary, when the temperature of the cooling liquid is higher, the contact of CM is turned off and the contact of V is turned on, whereby the refrigerating device is stopped and the switching device 18 is switched to the state in which the cooling liquid is returned through the heat exchanger 19. .

<Effects of the Invention> As is apparent from the above description, according to the present invention,
If the set temperature of the automatic control device is set appropriately, it will be another cooling means automatically in case of a high return cooling liquid temperature such that the refrigerant compressor is overloaded and the protector works. Since the use of the heat exchanger is switched to, it is possible to eliminate any trouble caused by the fact that the refrigerant compressor, which the user thought to be operating, was stopped.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a mold cooling device showing an embodiment of the present invention, FIG. 2 is an example of its electric circuit, and FIG. 3 is a schematic configuration diagram of a mold cooling device not according to the present invention. 4 ... Evaporator of refrigeration system, 7 ... Tank, 7a ... Tank upper chamber, 7b ... Tank lower chamber, 9 ... Mold, 10 ... Partition plate,
11 ... Liquid passage hole, 12 ... Heater, 14a, 14b ... Branch return flow path, 18 ... Switching device, 19 ... Heat exchanger, 20 ... Heat exchanger flow path, TH ... Automatic control device .

Claims (1)

(57) [Claims] 1. A cooling system in which a partition plate having liquid passage holes is attached to the inside of a tank containing a cooling liquid for cooling a mold, and the tank upper chamber is immersed in an evaporator of a refrigerating apparatus through the partition plate. In the mold cooling device in which the cooling liquid sent from the lower chamber of the tank to the mold for heat exchange is returned to the upper chamber of the tank and the lower chamber of the tank through the branch return flow channel, the branch return flow channel from the mold A switching device is provided in the flow path leading to, and a heat exchanger flow path having a heat exchanger is provided between the switching device and the branch return flow path, and when the coolant temperature is lower than a set temperature, the freezing is performed. The switching device is switched to a state in which the device is driven and the cooling liquid is returned without passing through the heat exchanger, and when the cooling liquid temperature is higher than a set temperature, the refrigeration device is stopped and the cooling liquid is heat-exchanged. Automatic control that switches the switching device to the state of returning through the vessel Mold cooling device, characterized in that a location.