JPH059134Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a cooling device for a plastic mold that needs to be maintained at a predetermined temperature higher than room temperature.

<Prior art> Liquid cooling in which an evaporator, which forms a refrigeration cycle together with a refrigerant compressor, etc., is placed in a tank that stores a coolant such as water or brine to cool the coolant in the tank. The device 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 below 40°C; if it rises above this, the degree of superheating of the suction gas of the refrigerant compressor becomes excessive, causing the temperature of the high-pressure gas to rise and the motor winding temperature to rise. There is a risk that this will lead to an abnormal increase in

<Problems to be solved by the invention> The problem when using the liquid cooling system using the above-mentioned refrigeration cycle as a cooling system for plastic molds 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 previously devised a mold cooling device shown in FIG. 3 that can be operated without any problems even in such cases,
A patent application was filed.

To briefly explain the mold cooling device shown in FIG. 3, A is a refrigerant circuit of a refrigeration cycle that is constructed by connecting a refrigerant compressor 1, a condenser 2, a dryer 3, an evaporator 4, an accumulator 5, etc., and 6 is a refrigerant circuit. Juan,
B is a coolant circulation circuit that returns the coolant stored in the tank 7 to the tank 7 via a circulation pump 8 and a load 9 such as a mold. The inside of this tank 7 is divided into an upper tank chamber 7 by a partition plate 10 having a liquid passage hole 11.
It is divided into two parts: a and a lower tank chamber 7b, and an upper tank chamber 7b.
An evaporator 4 is disposed in the tank a, and a heater 12 for adjusting the coolant temperature is disposed in the tank lower chamber 7b. The coolant circuit B connects the tank lower chamber 7b and the suction port of the circulation pump 8 through a delivery pipe 13, and in particular, the return pipe 14 from the load 9 is connected to a thin return pipe 14a connected to the tank upper chamber 7a. , and a relatively thick return pipe 14b connected to the lower tank chamber 7b, and inside the latter return pipe 14b, a resistor 15 for flow rate adjustment and a temperature sensor 16 for detecting the return temperature are provided. The temperature signal 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, due to the difference in the pipe diameters of the two return pipes 14a and 14b and the action of the resistor 15, the evaporator 4
By suppressing the amount of liquid that returns to the tank upper chamber 7a, even if the coolant temperature is as high as 50° C., the average temperature of the coolant in the tank upper chamber 7a is lowered to a temperature at which the refrigerant compressor can operate. It was something I made.

However, in the device shown in FIG. 3, the upper layer of the cooling liquid in the tank 7 is where the high temperature return cooling liquid that has taken heat from the load 9 flows through the return pipe 14a, and there is a coil at the end of the evaporator 4. Therefore, if the heat exchange between the refrigerant and the cooling liquid is complete, the temperature of the refrigerant leaving the evaporator 4 will rise to almost the same temperature as the high-temperature return cooling liquid. As a result, the degree of superheat increased significantly, and there was a possibility that the operation of the refrigerant compressor 1 would become impossible.

In the present invention, since the temperature of the coolant in the tank upper chamber becomes lower from the upper layer to the lower layer due to cooling by the evaporator, this point can be effectively utilized. By reconsidering the refrigerant circulation path and improving the structure of the partition plate 10, the degree of superheating of the refrigerant can be minimized, and even if the temperature of the coolant returning to the tank is high, the refrigerant compressor 1 can be The purpose is to provide a mold cooling device that enables smooth operation.

<Means for solving the problem> In the present invention, the refrigerant circuit of the refrigeration cycle is configured by connecting a refrigerant compressor, an evaporator, etc., and a cooling system in a tank in which the evaporator is immersed in a cooling liquid. A coolant circulation circuit that returns the liquid to the tank after passing through a load, wherein the inside of the tank is divided into upper and lower parts by a partition plate having liquid passage holes to form an upper tank chamber and a lower tank chamber. , the evaporator is provided in the upper chamber of the tank, a heater for adjusting the temperature of the coolant is provided in the lower chamber of the tank, and a coolant delivery pipe is connected;
The return flow path of the coolant that has passed through the load is branched into two return flow paths that connect to the upper tank chamber and the lower tank chamber, respectively, and the evaporator includes a first coil portion and a first coil portion. Refrigerant is supplied from the
and a second coil part disposed below the first coil part, and a refrigerant pipe connecting the second coil part and the refrigerant compressor is covered with a heat insulating material, This eliminates the harmful effects of high-temperature return coolant, thereby minimizing the degree of superheating of the refrigerant.

<Example> An embodiment of this 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. Figure 1 to 3
By comparing with the figure, the following points will be understood. That is, a tank 7 for storing a coolant is divided into upper and lower halves by a partition plate 10 having a liquid passage hole 11, and an evaporator 4 of a refrigerant circuit A is installed in an upper chamber 7a of the tank.
, the heater 12 is provided in the tank lower chamber 7b,
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 return pipe 14 from the load 9 is connected to a thin return pipe 14a connected to the tank upper chamber 7a, and a tank It branches into a relatively thick return pipe 14b that connects to the lower chamber 7b, and a resistor 15 for flow rate adjustment is provided inside the relatively thick return pipe 14b, and returns to the tank upper chamber 7a where the evaporator 4 is located. In addition to suppressing the flow rate of the coolant, there is also a coolant temperature sensor 16 and a control circuit 17 that operates based on the detection signal of the temperature sensor 16.
, the operation of the refrigerant compressor 1 and the heater 12
There is no particular difference between the two in terms of controlling the on/off of the liquid, but in the case of Figure 1, the
A liquid passage pipe 18 of an appropriate height is installed around the hole 1, and the evaporator 4 is disposed in the tank upper chamber 7a.
A first coil portion 4a that descends to near the upper end level of the liquid pipe 18 and is wound and ends at the upper layer of the cooling liquid in the tank 7, and a portion from the end of the first coil portion 4a to the vicinity of the partition plate 10. A second coil portion 4b is wound up and ends near the upper end level of the liquid pipe 18, and a second coil portion 4b rises from the end of the second coil portion 4b and covers the immersed area with the insulation material 2.
This differs from the case shown in FIG. 3 in that it includes an outlet pipe 19 coated with zero. Although the first coil portion 4a of the evaporator 4 in FIG. 1 is illustrated as a series of three coil groups, the present invention is not limited thereto, and the coils are wound at equal pitches from the beginning to the end of the winding. It may be something written. Insulation material 2
0 indicates heat resistance and liquid impermeability. Figure 2 shows a liquid passing pipe 18 inside the coil shape of the evaporator 4.
indicates that it is located.

Along with the above-mentioned structure of the evaporator 4, the circulation path of the refrigerant in the evaporator 4 is also changed to the liquid passage pipe 1.
Needless to say, the coolant flows from near the upper end level of the liquid passage pipe 18 toward the upper layer of the tank 7, and then from near the partition plate 10 toward the upper end level of the liquid passage pipe 18. Even with such a circulation path, the temperature distribution of the coolant in the tank 7 is basically the same as the case shown in FIG. 3 in that it becomes lower from the upper layer to the lower layer.
However, only the liquid layer corresponding to the height of the liquid passage pipe 18 erected on the partition plate 10 forms a cooling liquid layer having the lowest temperature. The second coil portion 4b corresponding to the latter stage of the evaporator 4 is located in the coolant layer having the lowest temperature formed as described above, and the immersed portion of the outlet pipe 19 is covered with a heat insulating material 20. As described above, the degree of superheat of the refrigerant after evaporation in the evaporator 4 can be suppressed to the minimum.

<Effects of the invention> In the mold cooling device of the invention, the refrigerant evaporated in the first coil part of the evaporator is connected to the second coil part placed in the lower temperature part of the upper tank chamber and covered with a heat insulating material. Since the refrigerant returns to the refrigerant compressor through the refrigerant piping, under operating conditions where the refrigerant compressor is operated at the very limit of its operable limit due to the high temperature return coolant, the refrigerant is Since the degree of superheat is kept to a minimum, it is extremely effective in that the refrigerant compressor can continue to operate without any problem even if the temperature of the return coolant is further increased.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a mold cooling device showing an embodiment of this invention, Fig. 2 is a plan view of the tank shown in Fig. 1, and Fig. 3 is a schematic diagram of a mold cooling device not based on this invention. It is. 1... Refrigerant compressor, 4... Evaporator, 7... Tank, 7a... Tank upper chamber, 7b... Tank lower chamber,
9... Load, 10... Partition plate, 11... Liquid passage hole,
12...Heater, 13...Cooling liquid delivery piping,
14, 14a, 14b...Return piping (return flow path),
18...Liquid passing pipe, 19...Evaporator outlet pipe, 20...Insulating material, A...Refrigerant circuit, B...Cooling liquid circulation circuit.

Claims (1)

[Scope of utility model registration request] A refrigerant circuit of a refrigeration cycle configured by connecting a refrigerant compressor, an evaporator, etc., and a refrigerant circulation circuit that returns the refrigerant in the tank in which the evaporator is immersed in the refrigerant to the tank after passing through the load. In the tank, the inside of the tank is divided into upper and lower parts by a partition plate having liquid passage holes to form an upper tank chamber and a lower tank chamber, the evaporator is provided in the upper tank chamber, and the lower tank chamber is divided into upper and lower chambers. A heater for adjusting the temperature of the coolant is provided in the tank, and a coolant delivery pipe is connected to the coolant, and a return flow path for the coolant that has passed through the load is connected to two return flow paths that respectively connect the tank upper chamber and the tank lower chamber. The evaporator has a first coil section and a first coil section.
A refrigerant is supplied from a coil section, and a second coil section is arranged below the first coil section, and the refrigerant pipe connecting the second coil section and the refrigerant compressor is made of a heat insulating material. A mold cooling device characterized by being covered with.