JPH01135604A - Cooling device of mold - Google Patents

Abstract

PURPOSE:To make temperature control ranging from low temperature to high temperature possible by automatically changing over from a refrigerating device to a cooling device other than the refrigerating device and vice versa by a method wherein a heat exchanger is jointly provided between a change-over mechanism and branched return flow paths and the refrigerating device is stopped and, at the same time, the change-over mechanism is changed over to the state that cooling liquid is sent back through the heat exchanger, when the temperature of the cooling liquid is higher than the set temperature. CONSTITUTION:A change-over mechanism 18 is provided in a flow path, which runs from a mold 8 to branched return flow paths 14a and 14b. When cooling liquid flows in the direction indicated with the arrow B, it divides from the change-over mechanism 18 and flows to a heat exchanger 19. When the temperature of the cooling liquid is higher than the set temperature, an automatic control device TH puts the contacts of a CM off and those of a V on, resulting in stopping a refrigerating device and, at the same time, in changing-over the change-over mechanism 18 to the state that the cooling liquid is sent back through the heat exchanger 19. By properly setting the set temperature of the automatic control device, the change-over is automatically done to the use of the heat exchanger or to another cooling means, when the temperature of the return cooling liquid is so high as to put a protector in actuation.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cold mold for a plastic mold that needs to be maintained at a predetermined temperature higher than room temperature.

<Conventional technology> An evaporator, which together with a refrigerant compressor and others forms a refrigeration cycle,
A liquid cooling device disposed in a tank for storing a cooling liquid such as water or brine to cool the cooling liquid in the tank is disclosed in, for example, Japanese Utility Model Publication No. 15107/1983, and is conventionally known. . The coolant temperature at which this refrigerant compressor can operate is normally 40'C or below, and if it becomes higher than this, the suction gas of the refrigerant compressor will be overheated t, f.
becomes excessive, leading to a rise in the temperature of the high-pressure gas and an abnormal rise in the temperature of the motor windings.

<Problems to be Solved by the Invention> A problem that arises when a liquid cooling device using the above-mentioned refrigeration cycle is used as a cooling device for a plastic mold is that the temperature is higher than that at which the refrigerant compressor can operate. This means that it may be set to the eye coolant temperature. The present applicant has previously devised a mold cooling device shown in FIG. 3, which can be operated without any problems even in such cases, and has filed a patent application.

A brief explanation of the mold cooling device shown in Fig. 3 is as follows.
A is refrigerant compressor 1, condenser 2, dryer 3, evaporator 4
, a refrigerant circuit of a refrigeration cycle configured by connecting an accumulator 5, etc., 6 is a fan, and B is a coolant circulation circuit that returns the coolant stored in the tank 7 to the tank 7 via the circulation pump 8 and the mold 9. be. Inside this tank 7 is a liquid passage hole 1.
The tank is divided into an upper tank chamber 7a and a lower tank chamber 7b by a partition plate 10, and the lower tank chamber 7a is equipped with an evaporator 4, and the lower tank chamber 7b is equipped with a heater 12 for adjusting the coolant temperature. has been set up. The coolant circuit B is located in the tank lower chamber 7b.
and the suction port of the circulation pump 8 are connected by a delivery piping 13. In particular, the return piping 14 from the mold 9 has a thin return piping 14a connected to the tank upper chamber 7a, and a relatively thick return piping 14a connected to the tank lower chamber 7b. It forms a branch return flow path with the pipe 14b, and inside the latter return pipe 14b there is a resistor 15 for adjusting the flow rate and a temperature sensor 1 for detecting the return temperature.
16 is provided, and the temperature signal of the temperature sensor 16 is sent to the control circuit 17.
The refrigerant is compressed! The operation of a1 and the on/off opening of the heater 12 are controlled linearly by A7.

In this way, due to the difference in the pipe diameters of the two return pipes 14a and 14b and the movement of the resistor 15, the amount of liquid returned to the tank upper chamber 7a where the evaporator 4 is located is suppressed, and the coolant temperature is reduced to 50°C, for example. The average temperature of the coolant in the tank upper chamber 7a is lowered to a temperature at which the refrigerant compressor can operate, even if the temperature is as high as 'C.

However, even in the apparatus shown in FIG. 3, if the coolant temperature is further increased, it is inevitable that the operating limit will be exceeded.

As described above, in the cooling system using the refrigeration cycle, when the coolant temperature becomes high, a load is placed on the refrigerant compressor 1, and the protector stops the compressor 1, but in the worst case, it may break down. On the other hand, in air-cooled and water-cooled heat exchange devices that use a different cooling method than the refrigeration cycle, especially in air-cooled heat exchange devices, the cooling capacity decreases if the temperature difference between the coolant and the maximum temperature is small. , the temperature of the mold cannot be maintained at a constant temperature. If a refrigeration system and other heat exchange equipment are installed together, and the switching is done manually, it is possible to switch at will, but under coolant temperature conditions that would cause the refrigerant compressor to stop, Although the user thought that the machine was being cooled, the operation was actually stopped, causing the temperature of the mold to rise and potentially causing defects in the molded product.

In view of the above-mentioned circumstances, the present invention has been developed to automatically switch between a refrigeration device and a cooling device other than the refrigeration device to control the temperature from low to high temperatures, thereby eliminating mistakes during use. Its purpose is to provide a cold fJl device.

<Means for solving the problems> The present invention provides a switching device in the flow path leading from the mold to the branch return flow path, and a heat exchanger is provided between the switching device and the branch return flow path. A flow path for a heat exchanger is also provided, and the refrigeration system is turned on and off depending on whether the coolant temperature is lower or higher than the set temperature, and the switching is made between returning the cooling liquid without going through the heat exchanger or returning it through the heat exchanger. An automatic control device has been installed to switch the device, allowing the system to be used safely from low to high coolant temperatures.

<Example> An embodiment of the present invention is shown in FIG.

In FIG. 1, parts and members that are the same as those shown in FIG. 3 are given the same reference numerals as those used in FIG. 3 for convenience of comparison. By comparing FIG. 1 with FIG. 3, the following points will be understood. That is, a tank 7 for storing a coolant is divided into upper and lower parts by a partition plate 10 having a liquid passage hole 11, an evaporator 4 of a refrigeration system is installed in an upper tank chamber 7a, and a heater 12 is installed in a lower tank chamber 7b. [pull point,
In the coolant circulation circuit B, only the tank lower chamber 7b is connected to the suction port of the circulation pump 8 by a coolant delivery pipe 13, but the mold 9
The return pipe 14 from the tank serves as a branch return flow path with a thin return pipe 14a connected to the tank upper chamber 7a and a relatively thick return pipe 14b connected to the tank lower chamber 7b. A resistor 15 for flow rate adjustment is provided to suppress the flow rate of the coolant returning to the tank lower chamber 7a where the evaporator 4 is located, and a coolant temperature sensor 16 is also provided.
A control circuit 17 that operates based on the detection signal of the temperature sensor 16
There is no particular difference between the two in that they control the operation of the refrigerant compressor 1 and the on/off of the heater 12.

However, in the case of FIG.
In the flow path leading to a and 14b, the flow path of the cooling liquid can be switched back to the two directions indicated by the arrow A and the arrow opening.
For example, a switching bag @18 such as a three-way solenoid valve is provided,
If it flows in the direction of arrow A, it will be returned to the upper tank chamber 78 and lower tank chamber 7b in the same way as in the previous step (E). However, when the flow is in the direction of the arrowhead, the flow branches off from the switching device 18 and returns to the branch return flow path 1/Ia.

After flowing into the flow path 20 of the heat exchanger 19, which has a common passage 14b, it is finally returned to the upper tank Z7a and the lower tank chamber 7b. This heat exchanger 19 may be of an air-cooled type or a water-cooled type, but if it is an air-cooled type, if it is arranged side by side with the condenser 2, the fan 6 can be used in common. As shown in the figure, a bypass tube 2 in which a resistor 22 is provided inside the pipe.
1, it is possible to adjust the flow rate of the coolant passing through one heat exchanger, that is, the amount of heat exchanged.

In the case of FIG. 1, an automatic control device TH such as Mostara 1 is provided. FIG. 2 shows an example of a circuit including the automatic control device TH. In Figure 2,
When the switch SW is turned on, the electric circuit of the motor FM of the fan 6 and the motor PM of the circulation pump 8 becomes a closed circuit, but the electric circuit of the motor CM of the refrigerant compressor 1 and the solenoid valve of the switching device 18 becomes a closed circuit.
About 50', which normally places a burden on the refrigerant compressor 1
If the coolant temperature is lower than the set temperature of the automatic control device TH in C, the automatic control device TH operates to turn on the CM contact and turn off the contact on the refrigeration system. At the same time, the switching device 1B is switched to a state where the cooling liquid is returned without passing through one heat exchanger. On the other hand, if the coolant temperature is higher, the CM contact is turned off and the contact (■) is turned on, thereby stopping the refrigeration system and switching the switching device 18 to return the coolant through the heat exchanger 19. .

<Effects of the Invention> As is clear from the above explanation, according to the present invention, if the set temperature of the automatic control device is properly set, it will be possible to prevent the protector from moving due to the load on the refrigerant compressor. When the return coolant temperature is high, the system automatically switches to using another cooling method, the heat exchanger, so the refrigerant compressor, which users thought was running, was stopped. Any trouble caused by this can be completely eliminated.

[Brief explanation of the drawing]

FIG. 1 is a schematic 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 diagram of a mold cooling device not according to the present invention. 4... Evaporator of refrigeration equipment, 7... Tank, 7a...
- Tank lower chamber, 7b... Tank lower chamber, 9... Mold,
DESCRIPTION OF SYMBOLS 10... Partition plate, 11... Liquid passage hole, 12... Heater, 14a, 14b... Branch return channel, 18...
Switching device, 19... Heat exchanger, 20... Heat exchanger flow path, T (... automatic? XJ device. Patent applicant: Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. Install a partition plate with liquid holes inside the tank that contains the coolant for cooling the mold, and through the partition plate, the upper chamber of the tank is connected to the cooling part where the evaporator of the refrigeration equipment is immersed, and the tank. The lower chamber is a heating section equipped with a heater, and the coolant sent from the lower tank chamber to the mold for heat exchange is returned to the upper tank chamber and lower tank chamber through a branch return flow path for mold cooling. In the apparatus, a switching device is provided in the flow path leading from the mold to the branch return flow path, and a heat exchanger flow path having a heat exchanger is provided between the switching device and the branch return flow path, and the cooling liquid is When the temperature is lower than the set temperature, the switching device is switched to a state in which the refrigeration device is driven and the coolant is returned without passing through the heat exchanger, and when the coolant temperature is higher than the set temperature, the refrigeration device is operated. 1. A mold cooling device comprising: an automatic control device for switching the switching device to a state in which the cooling liquid is stopped and the cooling liquid is returned through the heat exchanger.