JPH09295317A - Temperature conditioning apparatus for plastic molding mold and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change over a heating medium easily in a short time with cross over prevented even when water of especially high heat transfer efficiency is used as the heating medium and to curtail the total molding cycle remarkably. SOLUTION: In a mold temperature conditioning apparatus, a high temperature heating medium supply apparatus 2 for supplying a high temperature heating medium (hereafter designated as A) and a low temperature heating medium supply apparatus 3 for supplying a low temperature heating medium (hereafter designated as B) are arranged independently, A and B supplied respectively are made to flow alternately into a line for supplying the heating medium into a mold 1 by the change-over operation of valves 15-22 to change mold temperature. Closed type heating medium storage tanks 5, 6 are installed in the mold bypass line of A and the mold bypass line of B respectively, and a pressure control means by pressurized gas for controlling the pressure of the line for supplying the heating medium into the mold 1 at a prescribed value is provided in each of the tanks 5, 6. In this way, the cross over of the high temperature and mold temperature heating media is prevented so that a molding cycle can be curtailed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold temperature control device and a mold temperature control method for plastic molding in blow molding, injection molding, slush molding and the like.

[0002]

2. Description of the Related Art Generally, in molding a thermoplastic resin, when molding is performed with a constant mold temperature, the higher the mold temperature, the better the transferability of the mold surface, but the longer the cooling time. Especially in blow molding, there is a problem that the molding cycle becomes very long if the die temperature is raised in order to apparently eliminate the die line generated during the extrusion of the parison in the blowing process.

Therefore, conventionally, a method of raising and lowering the mold temperature in one cycle has been used in order to achieve both good transferability and a short molding cycle. As this method, a method of flowing a high temperature fluid for heating the die and a low temperature fluid for cooling through the same flow path in the die by switching the inlet and outlet valves of the die is used. However, in this method, for example, when switching from cooling to heating, flow of residual low temperature water into the circuit on the heating side in the piping between the inlet valve and the outlet valve including the flow path in the mold occurs, The high-temperature water supply device also needs to heat the extra low-temperature water that has flowed in, leading to heat loss and an increase in cycle time.

In order to prevent the oil from flowing into the circuit on the opposite side when oil is used as the heat medium, Japanese Patent Publication No. 4-44 is used.
No. 6 discloses, for example, when hot oil supplied to a mold part is switched to cold oil, hot oil remaining in a fluid supply line inside the mold and piping in the middle crosses a cold oil tank. In order to prevent overshooting, first of all, a method is shown in which pressurized gas is supplied at the same temperature and pressure as hot oil to expel residuals together with pressurized gas to the hot oil tank, and then cold oil is circulated. ing.

[0005]

However, in this method, it is necessary to independently control the pressure of the gas body to a high temperature and a low temperature, and at the same time to separate the gas and the heat medium in the storage tank of each heat medium. Equipment becomes complicated. Furthermore, since the heated / pressurized gas stays in the fluid supply pipe and piping of the mold part when switching to gas, the switching response to cold oil is extremely delayed and the molding cycle becomes longer. There is also a problem. Moreover, the temperature of the low temperature heat medium is 10
If oil is used as the heat medium when the temperature is lower than 0 ° C., there is a very serious problem in terms of cooling efficiency.

That is, since oil has a viscosity several ten to several hundred times higher than that of water, practically, when oil is flowed at a temperature lower than 100 ° C., it becomes a laminar flow, and the film heat transfer coefficient is lowered. As a result, the amount of heat transfer decreases and the cooling efficiency becomes extremely poor. Therefore, in order to generate a turbulent flow and increase the film heat transfer coefficient, a large flow rate of several tens to several hundreds of times is required as compared with the case of flowing water. Considering only the velocity, the pressure loss is proportional to the square of the flow velocity, so that the pressure drop will be hundreds to tens of thousands of times lower than in the case of flowing water. From this, a high temperature fluid for heating and a low temperature fluid for cooling are made to flow in the same flow path in the mold by switching the inlet and outlet valves of the mold, and the temperature of the low temperature fluid is higher than 100 ° C. If low, it is most preferred to use water as the heating medium.

However, when high temperature water for heating and low temperature water for cooling are made to flow as the heat medium in the same flow path in the mold by switching valves at the inlet and outlet of the mold, for example, the low temperature water is the mold. When the water is supplied to the mold part, first, by supplying the low temperature water, the residual part of the high temperature water is heated to a high temperature so that the residual part of the high temperature water in the fluid supply line of the mold part and the intermediate piping does not cross over to the low temperature water tank. If you try to apply the method of ejecting to the water tank and then circulating cold water,
There is a problem that it cannot be applied when it takes a long time to switch or when the temperature difference between the high temperature water and the low temperature water is large.

That is, when the temperature of the high temperature water exceeds 100 ° C., the vapor pressure of the water may reach several atmospheric pressures, and the high temperature water in the pipes and pipes is expelled to the high temperature water tank by supplying the low temperature water. In addition, the low-pressure water extrusion pump requires an extrusion pressure that is the vapor pressure of the high-temperature water plus the pressure loss in the pipe. Therefore, if the pump does not have sufficient pushing capacity, the flow rate will be small and it will take a long time to switch.If the pump has a smaller pushing capacity, water will flow backward in the direction it should flow, and it will not be possible to expel it. There is a problem that becomes.

In view of this, the present invention provides a mold temperature for raising and lowering the mold temperature by switching between a high-temperature heat medium and a low-temperature heat medium to a heat medium supply line in the mold in order to improve the mold transfer property of a molded product. In the adjusting device, even if the heat medium is a normal heat medium, or particularly when water having a high heat transfer efficiency is used as the heat medium, it is easy to switch the heat medium while preventing crossover,
It is an object of the present invention to provide a mold temperature control device and a mold temperature control method thereof that can be performed in a short time and can significantly reduce the entire molding cycle.

[0010]

DISCLOSURE OF THE INVENTION As a result of various investigations by the inventors of the present invention to achieve the above object, a heat medium storage tank provided with pressure control means by pressurized gas is arranged in a mold bypass line of each heat medium. Then, they have found that the above problems can be solved by controlling the heat medium supply line into the mold to a predetermined pressure, and completed the present invention. That is, the mold temperature control device of the present invention includes a high-temperature heat medium supply device that supplies a high-temperature heat medium (hereinafter referred to as A) to a heat medium supply line into the mold and a low-temperature heat medium (hereinafter referred to as B). A low-temperature heat medium supply device for supplying
In the mold temperature controller that raises and lowers the mold temperature by alternately flowing B and B to the heat medium supply line into the mold by switching the valves, the mold bypass line A and the mold bypass line B Each heat medium storage tank is arranged,
Further, each heat medium storage tank is provided with a pressure control means by a pressurized gas for controlling the heat medium supply line into the mold to a predetermined pressure.

Here, the heat medium storage tank is at least a closed type, and the purpose is to circulate or retain the heat medium in the heat medium supply line or the mold bypass line circuit during mold temperature control. Of course, it does not exclude the inflow and outflow of gas (hereinafter the same). Further, the predetermined pressure does not mean that all the parts in the heat medium supply line etc. are constant, but the pressure of each part may be slightly different due to pressure loss, back pressure, etc. It refers to the pressure state that is controlled to exert its function at each stage such as heating.

In the above-mentioned present invention, each heat medium supply device includes a hermetically sealed tank having a constant inner volume, a pump, a heater, and optionally a cooler, and the heat medium supply device and the mold. The heat medium supply line to the inside and the bypass line form a closed circuit that is always filled with the heat medium, and the heat medium storage tank of the bypass line has a gap even if it receives the equivalent amount of the residual heat medium pushed out at the time of switching. The volume that can be left is preferable. Here, the "sealed" tank in the heat medium supply device means that the heat medium circulates or stays in the heat medium supply line or the mold bypass line circuit at least during mold temperature control, and the heat medium itself. It is not excluded that the heat medium of a predetermined temperature is separately supplied to control the temperature of 1, while discharging the circulating heat medium (hereinafter the same).

The pressure control means provided in the upper space of each heat medium storage tank of the bypass line according to the present invention is a pressurized gas supply line communicating with (a pressure regulator of) an external pressure source through an on-off valve. And a pressurized gas discharge line communicating with the relief valve to the atmosphere via the open / close valve.

Further, as the valve switching operation in the present invention, normally, the heat medium from each heat medium supply device is always circulated in either the heat medium supply line into the mold or the bypass line. In the mold, one of the heating medium A
Immediately before switching from (or B) to the other heat medium B (or A), pressurized gas is supplied to the heat medium storage tank of B (or A), and A (or B) remaining in the mold is also supplied. It is preferable that B) is extruded and replaced by B (or A) supplied from the other heat medium supply device.

The mold temperature control method of the present invention includes a high temperature heat medium supply device for supplying a high temperature heat medium (hereinafter referred to as A) to a heat medium supply line into the mold and a low temperature for the same heat medium supply line. A low-temperature heat medium supply device for supplying a heat medium (hereinafter referred to as B) is independently arranged, and A and B supplied from each are alternately switched to the same heat medium supply line in the mold by switching valves. In the mold temperature control method in which the mold temperature is raised and lowered by flowing, the pressure in the heat medium storage tanks arranged in each of the A mold bypass line and the B mold bypass line is increased to a pressure higher than the vapor pressure of A. It is characterized by controlling.

As a valve switching operation method in the mold temperature control method of the present invention, the heat medium supplied from each heat medium supply device is usually either a heat medium supply line into the mold or a bypass line. While constantly circulating the crab,
When the inside of the mold is switched from one A (or B) to the other B (or A), pressurized gas is supplied to the heat medium storage tank of B (or A), and the back pressure generated thereby is reduced. A (or B) remaining in the mold is supplied from the other heat medium supply device by acting in the heat medium supply device and controlling the heat medium supply line into the mold to a predetermined pressure or higher. It is preferable to extrude and replace with B (or A).

The present invention will be described in more detail below. In the present invention, temperatures shown as high temperature and low temperature are not absolute. The high temperature is the temperature of the heat medium for raising the mold temperature to give a sufficient mold transfer property when molding, and the low temperature is the sum of the time required for cooling the molded product and the time required for heating. It is the temperature of the heat medium for lowering to the minimum mold temperature, that is, it changes depending on the resin used, molding conditions and the like.

In the present invention, the heat medium that can be used is not particularly limited and may be an ordinary organic heat medium depending on temperature conditions. However, it is preferable to use water from the viewpoints of easy handling, fluidity and heat transfer efficiency. In this case, as the water as the high-temperature heat medium, pressurized hot water of 100 ° C. or higher is usually used, and as the low-temperature heat medium, the water is
In order to enhance the cooling effect, 100 ° C or lower, preferably 5
Cold water below 0 ° C is used.

Further, the pressurized gas used in the present invention should be at least the pressure possessed by the high temperature heat medium, for example, if it is pressurized hot water of 100 ° C. or higher, it should be compressed to its vapor pressure or higher, such as air or Nitrogen gas or the like can be used. The pressurized gas does not mix and flow with each heat medium, but only comes into contact with the liquid surfaces of the high temperature and low temperature heat medium storage tanks, so that it is not necessary to control the temperature to an independent temperature.

Furthermore, in the above-mentioned present invention, the heat medium supply device and the heat medium supply line to the mold and the bypass line always form a closed circuit of the heat medium means that the heat medium is passed through the heat medium passage circuit. Refers to a state in which the medium is filled and at least there is no open-air portion (however, access to and from pressurized gas is allowed in this case), which allows the pressurized medium to act on the heat medium storage tank of the bypass line. The generated back pressure can be applied to the heat medium supply device to control the heat medium supply line into the mold to a predetermined pressure or higher.

The operation of the mold temperature control apparatus and the mold temperature control method of the present invention is performed by switching the on-off valves according to a schedule preset according to molding conditions. As a general schedule, (1) heating the inside of the mold to a predetermined temperature, (2) maintaining the inside of the mold at a predetermined heating temperature for a certain period of time, and (3) heating the inside of the mold Switching to cooling, (4) cooling the inside of the mold to a predetermined temperature, (5) maintaining the inside of the mold at a predetermined cooling temperature for a certain time, (6) heating the inside of the mold from cooling Each on-off valve is automatically switched according to the schedule, with the step of switching to (1) as one cycle.

Particularly, when the heat medium is switched in (3) or (6), for example, when switching from a high temperature to a low temperature, the high temperature heat medium remaining in the mold due to the extrusion with the low temperature heat medium is stored in a storage tank for the high temperature heat medium. Also, when switching from cooling to heating, the valve is operated to be opened and closed when the low temperature heat medium remaining in the mold due to extrusion by the high temperature heat medium is returned to the low temperature heat medium storage tank. In this case, in order to push out the heat medium remaining in the mold in a short time, in the present invention, the back pressure generated by the pressure control operation of supplying the pressurized gas to the heat medium storage tank to be replaced is supplied from the return line to the heat medium supply device. It has the greatest feature that the discharge pressure of the pump is raised by acting on, for example, a closed tank, and the pressure of the heat medium supply line into the mold is raised. In addition, as each switching valve used in the present invention, a solenoid operated valve, an electromagnetic valve, or the like can be used, and the opening and closing thereof is automatically performed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. In the following description, pressurized hot water of 100 ° C. or higher is used as the high-temperature heat medium,
The case where low-temperature water of 100 ° C. or lower is used as the low-temperature heat medium will be described, but the present invention is not limited to this example.

First, FIG. 1 is a schematic view of the mold heating and cooling pipes shown as a reference example, and FIG. 2 is a schematic view of the mold heating and cooling pipes of the present invention. Fig. 1 (2
In the same figure), 1 is a mold for plastic molding, 2
Is a high-temperature heat medium supply device (hereinafter, referred to as high-temperature water supply device), which normally has a closed tank, a pump, a heater, a cooler and the like having a constant inner volume. 3
Is a low-temperature heat medium supply device (which will be described below as a low-temperature water supply device), which usually has a sealed tank, a pump, a heater, a cooler and the like having a constant internal volume. The high temperature water discharged from the high temperature water supply device 2 to the discharge line 23 by the pump is branched into two, one of which is the switching valve 17,
It is supplied to the mold 1 through the heat medium supply line 31 via the supply path 27 to the mold 1, and after passing through the mold, the switching valve 18,
It flows into the high-temperature water supply device 2 via the return line 24. When the heat medium supply line 31 is not supplied, it flows through the other switching valve 15 through the mold bypass line 28 of the high temperature water supply system, then through the switching valve 16 and the return line 24 and flows into the high temperature water supply device 2. .

Similarly, the low-temperature water supplied from the low-temperature water supply device 3 to the discharge line 25 by the pump is branched into two,
One is supplied to the mold 1 through the switching valve 19, the supply path 29 to the mold 1 and the heat medium supply line 31, and after passing through the mold, the low temperature water supply device 3 via the switching valve 20 and the return line 26. Flow into. When the heat medium supply line 31 is not supplied, it flows through the other switching valve 21 through the mold bypass line 30 of the low-temperature water supply system, and then through the switching valve 22 and the return line 26 into the high-temperature water supply device 3. . That is, in the mold heating stage, the switching valves 17 and 18 are opened from the discharge line 23 from the high temperature heat medium supply device,
High temperature water is supplied to the mold 1 by closing the switching valves 15, 16, 19, 20. At this time, one of the low temperature water is circulated from the low temperature water supply device 3 to the return line 26 through the bypass line 30. In the mold cooling stage, the switching valves 19, 20 are opened and the switching valves 17, 18, 21, 2 are opened.
By closing 2 the low temperature water is supplied to the mold 1.
At this time, one of the high temperature water is circulated from the high temperature water supply device 2 through the bypass line 28 to the return line 24.

Further, for example, at the stage of maintaining the mold at a constant temperature, if the switching valves 17, 18, 19, 20 are closed, water is not supplied into the mold and remains there. In this case, the low-temperature water can be circulated in the bypass line at the stage of supplying the high-temperature water into the mold or retaining the high-temperature water in the mold. That is, while the switching valves 19 and 20 are closed, the switching valves 21 and 22 are opened and low-temperature water is re-cooled by bypassing low-temperature water from the mold to raise the temperature by cooling the mold in the previous stage. Is possible. Similarly, hot water may be circulated through the bypass line at the stage of supplying low temperature water into the mold or retaining low temperature water in the mold. That is, while the switching valves 17 and 18 are closed,
By opening the switching valves 15 and 16 and allowing high-temperature water to flow by bypassing the mold, it is possible to reheat the high-temperature water whose temperature has been lowered by the mold heating in the previous stage. Therefore, in order to realize heating / cooling by simply switching high-temperature water and low-temperature water, it is possible to open / close the switching valves 15 to 22 as shown in Table 1 below.

[0027]

[Table 1]

However, in such a switching cycle by the switching valve in the reference example, the high temperature water remaining in the mold flows into the low temperature water supply system or the low temperature water remaining in the mold high temperature water supply system. However, there is a drawback that extra cooling or heating is required due to the inflow of water.
Therefore, in the present invention, a piping system as shown in FIG. 2 is further added to the reference example shown in FIG. 1 and the operation described below is performed.

First, as shown in FIG. 2, in the middle of the bypass line 28 of the mold of the high temperature water supply system, the height of the closed mold having a volume larger than the volume of the heat medium (water) remaining in the mold. A heating medium storage tank 5 is provided, and two pipes for pressurized gas are connected to the upper part thereof. One is an external pressure source 4 such as a compressor, a pressure regulator 7, a switching valve 11
Is a compressed gas supply line 32, and the other is a compressed gas release line 33 that is released into the atmosphere via the switching valve 12 and the relief valve 9.

Similarly, a closed low-temperature water storage tank 6 having a volume larger than the volume of water remaining in the mold is provided in the middle of the mold bypass line 30 of the low-temperature water supply system. Two pipes for pressurized gas are connected to the upper part thereof. One is a compressed gas supply line 34 from the external pressure source 4 through the pressure regulator 8 and the switching valve 13, and the other is a compressed gas release line 35 that is discharged into the atmosphere through the switching valve 14 and the relief valve 10. is there. Pressure setting device 7, 8
It is advisable to preset the set pressure of 1 and the set pressure of the relief valves 9 and 10 to be higher than the vapor pressure of water at the temperature of the high temperature water so that the high temperature water does not boil. In this case, in order to prevent the gas from the compressor from escaping as it is, the set pressures of the pressure setters 7 and 8 are set to the relief valves 9 and 10.
It is recommended to set the pressure slightly higher than the set pressure of. Also,
Only in the high temperature → low temperature switching stage, the pressure setting device 7,
The set pressure such as 8 may be set higher than the vapor pressure of the high temperature water. If the pressure source 4 such as a compressor has a pressure setting function, the pressure setters 7 and 8 may be omitted.

The switching operation of each switching valve 11 to 22 at each stage of heating / cooling of the mold according to the present invention is summarized in Table 2 and will be described below. (1) Mold heating stage Each switching valve is in the open / closed state of “when the mold is heated” in Table 2. That is, high-temperature water flows in the heat medium supply line 31 to the mold 1, and low-temperature water bypasses the mold. However, in this case, the liquid level is lowered in the high temperature water storage tank 5 to such an extent that air does not enter the bypass line 28 of the mold of the high temperature water supply system. On the other hand, the low-temperature water storage tank 6 is in a state in which low-temperature water corresponding to the amount of the water in the high-temperature water storage tank 5 plus the amount of water remaining in the mold is added to raise the liquid level. Leave. This can be done by setting the amount of each heat medium filled in the circuit when the circulation line of each heat medium constitutes a closed circuit. Further, it is preferable that the inside of each storage tank is pressurized with pressurized gas to a pressure higher than the vapor pressure of the high-temperature water in advance.

(2) Mold high temperature maintaining step When the mold reaches a predetermined temperature, the switching valves 11 to 22 are opened / closed in "mold high temperature maintenance" in Table 2. That is, in this case, both the high temperature water and the low temperature water bypass the mold, and the high temperature water remains in the mold and is maintained at a high temperature. (3) High temperature → low temperature switching stage Next, when switching to mold cooling, the switching valves 11 and 2
2 is the opened / closed state of "when switching from high temperature to low temperature" in Table 2. That is, in this case, the low temperature water pushed out from the low temperature water storage tank 6 by the pressurized gas (air pressure) supplied to the low temperature water storage tank 6 via the switching valve 13 is supplied from the switching valve 22 via the return line 26 to the low temperature water supply. It flows into the closed tank (not shown) of the device 3 and acts as back pressure on the suction side of the pump. In this case, the hot water mold bypass line 28
The liquid level drops to the point where air does not enter.

Therefore, the low-temperature water discharged from the low-temperature water supply device 3 is pushed out to the return line 24 to the high-temperature water supply device 2 through the switching valve 18 of the high-temperature water remaining in the mold under the back pressure. , Flows into a closed tank (not shown) of the high-temperature water supply device 2 and acts as back pressure on the suction side of the pump. The high-temperature water discharged from the high-temperature water supply device 2 is stored in the high-temperature water storage tank 5 and the liquid level rises. Since the air in the upper part of the tank 5 which is compressed by the high temperature water flowing into the high temperature water storage tank 5 is released into the atmosphere through the switching valve 12 and the relief valve 9, the pressure in the high temperature water storage tank 5 is constant. Kept in.

(4) Mold cooling stage The timing at which the high temperature water remaining in the mold is completely replaced by the low temperature water is measured, and the switching valves 11 to 22 are opened and closed as shown in Table 2 "when the mold is cooled". . That is, in this case, low-temperature water flows through the heat medium supply line 31 to the mold 1, and high-temperature water bypasses the mold. (5) Mold low-temperature maintaining step When the mold reaches a predetermined temperature, the switching valves 11 to 22 are set to the open / close state of "Maintaining the mold low temperature" in Table 2. That is, in this case, both the high temperature water and the low temperature water bypass the mold, and the low temperature water remains in the mold and is maintained at a low temperature.

(6) Low temperature → high temperature switching step Next, when switching to die heating, the switching valves 11 to 22 are opened / closed as shown in Table 2 “Low temperature → high temperature switching”. That is, in this case, the high-temperature water pushed out of the high-temperature water storage tank 5 by the pressurized gas (air pressure) supplied to the high-temperature water storage tank 5 through the switching valve 11 is supplied from the switching valve 16 through the return line 24 to the high-temperature water supply. It flows into the closed tank (not shown) of the device 2 and acts as back pressure on the suction side of the pump. In this case, the hot water mold bypass line 28
The liquid level drops to the point where air does not enter.

Therefore, the high-temperature water discharged from the high-temperature water supply device 2 is pushed out to the return line 26 to the low-temperature water supply device 3 through the switching valve 17 of the low-temperature water remaining in the mold with the back pressure applied. , Flows into a closed tank (not shown) of the low temperature water supply device 3 and acts as back pressure on the suction side of the pump. The low-temperature water discharged from the low-temperature water supply device 3 is stored in the low-temperature water storage tank 6 and the liquid level rises. The air in the upper part of the tank 6 that is compressed by the low temperature water flowing into the low temperature water storage tank 6 is the switching valve 14 and the relief valve 10.
As a result, the pressure in the low temperature water storage tank 6 is kept constant. The timing at which the low-temperature water remaining in the mold is completely replaced by the high-temperature water is measured, and the switching valves 11 to 22 are brought into the open / close state during heating of the mold shown in Table 2.
In this case, as described in (1) above, high temperature water flows through the mold and low temperature water bypasses the mold. The following (1)-
The step (6) is repeated.

[0037]

[Table 2]

[0038]

According to the present invention described above, the crossover between the high temperature heat medium and the low temperature heat medium is surely prevented, and even when water is used as the heat medium, the high temperature water and the low temperature water are Since the pressure difference due to the vapor pressure at the time of switching is eliminated, unnecessary load is not applied to the pump, and switching is accomplished in a short time, so that the molding cycle is significantly shortened. Further, since it is not necessary to stop the pump in the heat medium supply device, the heating or cooling efficiency of each heat medium in the heat medium supply device does not decrease. By repeating the operation of the present invention, by controlling the temperature of the mold by switching between the high temperature heat medium and the low temperature heat medium, blow molding, injection molding,
It is possible to easily obtain a molded product such as slush molding which has improved mold transferability.

[Brief description of drawings]

FIG. 1 is a schematic view of piping for heating and cooling a mold of a reference example.

FIG. 2 is a schematic diagram of piping for heating and cooling a mold in the present invention.

[Explanation of symbols]

1 Mold for Plastic Molding 2 High Temperature Heat Medium Supply Device 3 Low Temperature Heat Medium Supply Device 4 External Pressurization Source for Supplying Compressed Gas 5 High Temperature Heat Medium Storage Tank 6 Low Temperature Heat Medium Storage Tank 7, 8 Pressure Regulator 9 , 10 Relief valve 11, 12, 13, 14 Switching valve in pressurized gas pipe 15, 16, 17, 18, 19, 20, 21, 22 Switching valve in heat medium pipe 23 High-temperature heat medium discharge line 24 Return Line for High Temperature Heat Medium 25 Discharge Line for Low Temperature Heat Medium 26 Return Line for Low Temperature Heat Medium 27 Supply Route for High Temperature Heat Medium to Mold 28 Mold Bypass Line for High Temperature Heat Medium 29 Mold for Low Temperature Heat Medium to Mold Supply path 30 Bypass line for low temperature heat medium mold 31 Heat medium supply line to mold 32 (34) Compressed gas supply line 33 (35) Compressed gas release line

Claims (7)

[Claims] 1. A high temperature heat medium supply device for supplying a high temperature heat medium (hereinafter referred to as A) to a heat medium supply line into a mold.
Similarly, a low temperature heat medium supply device for supplying a low temperature heat medium (hereinafter referred to as B) is arranged independently, and A and B supplied from each are connected to a heat medium supply line into a mold by switching valves. In a mold temperature controller that raises and lowers the mold temperature by alternately flowing, heat medium storage tanks are respectively arranged in the A mold bypass line and the B mold bypass line, and each heat medium storage tank is A plastic molding die temperature control device comprising a pressure control means by a pressurized gas for controlling a heat medium supply line into the die to a predetermined pressure. 2. Each heating medium supply device has a closed tank, pump, and heater with a constant internal volume,
Further, the heat medium supply device and the heat medium supply line to the mold and the bypass line always form a closed circuit of the heat medium, and the heat medium storage tank of the bypass line stores a portion of the residual heat medium pushed out at the time of switching. The plastic molding die temperature control device according to claim 1, wherein the volume is such that a void can be left even if received. 3. A pressurized gas supply line communicating with an external pressurization source via an opening / closing valve and a pressure relief valve to the atmosphere via an opening / closing valve above the space of each heat medium storage tank of the bypass line. The temperature control device for a plastic molding die according to claim 1 or 2, further comprising a pressure control means including a pressure gas discharge line. 4. The valve switching operation is usually performed so that the heat medium from each heat medium supply device always circulates in either the heat medium supply line into the mold or the bypass line, and in the mold. When switching from one heat medium A (or B) to the other heat medium B (or A), B (or A)
While pressurized gas is supplied to the heat medium storage tank of
The plastic molding die according to claim 1, which is operated so that A (or B) remaining in the die is extruded and replaced by B (or A) supplied from the other heat medium supply device. Temperature control device. 5. A high temperature heat medium supply device for supplying a high temperature heat medium (hereinafter referred to as A) to a heat medium supply line into a mold,
A low-temperature heat-medium supply device for supplying a low-temperature heat-medium (hereinafter referred to as B) to the same heat-medium supply line is independently arranged, and A and B supplied from each are made the same in the mold by switching valves. In the mold temperature control method in which the mold temperature is raised and lowered by alternately flowing to the heat medium supply line, the pressure in the heat medium storage tanks arranged in each of the A mold bypass line and the B mold bypass line is set to A A method for controlling mold temperature, which comprises controlling the pressure to be higher than the vapor pressure of. 6. A valve switching operation, in which the heat medium normally supplied from each heat medium supplying device is constantly circulated in either a heat medium supply line into the mold or a bypass line, and From one A (or B) to the other B
At the time of switching to (or A), the pressurized gas is supplied to the heat medium storage tank of B (or A), and the back pressure generated thereby is applied to the heat medium supply device to heat the mold. By controlling the medium supply line to a predetermined pressure or higher, A (or B) remaining in the mold is pushed out and replaced by B (or A) supplied from the other heat medium supply device. Item 5. The mold temperature control method according to item 5. 7. A is high-pressure hot water of 100 ° C. or higher, and B
Is low temperature water of 100 ° C. or lower, and the mold temperature control method according to claim 5 or 6, wherein