JPH0677948B2 - Mold temperature controller - Google Patents

Description

The present invention relates to a mold temperature adjusting device for controlling the temperature of a mold for molding synthetic resin or the like within a predetermined range.

(Prior Art) As a device for cooling a mold with a refrigerant for controlling the temperature of a mold for molding synthetic resin or the like, and cooling the refrigerant whose temperature has risen again, as shown in FIG. The medium that has undergone heat exchange in the inside and has a temperature rise is sent to the cooler 32 by the action of the pump 34, is sufficiently cooled by the heat exchanger 33 there, and is then heated by the heater 35 to have an appropriate temperature. Adjusted to. The medium temperature is detected by a temperature detector 38 installed downstream of the heater 35, and the heat generation amount of the heating element 36 is adjusted based on the difference from the set temperature to control the temperature to an appropriate temperature. 37 is a power source that can be adjusted.

In this conventional device, since the medium is once cooled to a predetermined temperature or lower by the cooler 32 and then heated by the heater 35 to adjust the temperature, the loss of thermal energy is large and an expensive power control device such as a thyristor is required. , The production cost becomes expensive. In addition, the medium that has undergone heat exchange in the mold has the same cycle temperature as the shot cycle of the injection molding machine due to the temperature change of the mold when heated and melted synthetic resin is injected into the mold and filled. Although the change is repeated, the conventional device has a drawback that the medium temperature at the mold inlet is not stable and the controllability is poor because the device does not have a temperature fluctuation buffer.

(Means for Solving Problems) In order to eliminate the conventional drawbacks, the present invention eliminates thermal energy loss and saves energy by improving the piping condition and using a tank having a function of buffering temperature fluctuations. In addition, the manufacturing cost can be reduced, and precise, prompt and stable temperature control can be achieved.

(Embodiment) FIG. 1 is an example showing the structure of the present invention, in which water is used as a medium, and water which has passed through the mold 12 and has undergone heat exchange with the mold to raise its temperature. Is guided to the drain pipe 14 and passed through the status mixer 1 to the temperature fluctuation buffers 15a and 15b.
It is temporarily stored in the refrigerant storage tank 2 provided with. The water flowing through the discharge pipe 14 from the mold 12 changes in temperature in the same cycle as the shot cycle of the injection molding machine due to the temperature change of the mold when the molten synthetic resin is injected and filled in the mold. Is repeating. The fluctuation is removed by the temperature fluctuation buffers 15a and 15b attached to the tank 2, the temperature of the water is stabilized, the pressure is increased by the pump 4, and the water is guided to the water pipe 16 and the mold
Sent to 12. The cooling pipe 17 is provided downstream of the discharge side of the pump 4.
Is branched and cooled by the heat exchanger 21 in the cooler 7,
In the embodiment shown in FIG. 1, it is further branched into two systems, a primary cooling pipe 18a and a secondary cooling pipe 18b. The primary cooling water is guided to the primary cooling pipe 18a, merges with the return water of the mold flowing through the drain pipe 14 through the valve 6, and returns to the tank 2 through the static mixer 1. In this case, the return water is primarily cooled.
The secondary cooling water is guided to the secondary cooling pipe 18b and the small control valve 5
Immediately before the suction side of the pump 4, it merges with the water flowing through the water pipe 16 to perform secondary cooling for fine adjustment. A temperature detector 9 is installed near the entrance to the mold 12, and the valve opening of the control valve 5 is adjusted based on the difference between the set temperature and the detected temperature to precisely and stably control the supply temperature to the mold 12. To do.

In addition, a heater 19 having a heating element 3 is placed in parallel in the tank 2, and the valves 10 and 13 are closed and the valve 11 is opened to raise the temperature to a preset temperature at the time of startup, and the refrigerant is circulated to preheat it to the preset temperature. To do.

2 and 3 show another embodiment, which is a cooling pipe 17
This corresponds to the case where the flow rate of the refrigerant flowing through the cooling device 7 and heat-exchanged in the cooler 7 is small. In FIG. 2, the pipe 18a shown in FIG. 1 is not provided and only the pipe 18b is used. In FIG. 3, the pipe 18b is omitted and only the pipe 18a is used. The other parts have the same reference numerals as those in FIG. 1 and indicate the same parts.

Which of these two embodiments is used depends on the accuracy, container and reaction rate required for the apparatus. For example, when precise control is required, a system such as that shown in FIG. 2 equipped with a highly sensitive and highly accurate temperature detector 9, a control valve 5, a control system, and a cooler and a cooling device with good stability. Use
When not requiring very precise control, a system as shown in FIG. 3 is used, which has a reaction rate lower than that in the case of FIG. 2 but is basically stable.

When the flow rate of the refrigerant that flows through the cooling pipe and is heat-exchanged in the cooler 7 is large, the primary cooling is performed downstream of the cooler 7 in order to improve the mixing property and the thermal stability, as shown in FIG. A system as described with reference to FIG. 1 is used by branching to a pipe 18a and a secondary cooling pipe 18b. In this case, the pipes are increased as compared with the systems shown in FIGS. 2 and 3, but the mixing property and the cooling effect are improved.

(Effect) The present invention has such a structure, and a device for cooling the mold with a coolant and then cooling the coolant whose temperature has risen, a tank capable of buffering temperature fluctuations, and a cooling for the coolant flowing through the tank. Equipped with a device for adjusting the amount of mixed refrigerant that has been mixed, the heating control system such as a heater is eliminated, energy loss can be eliminated to reduce energy consumption, production costs can be reduced, and precise, prompt and stable temperature control can be performed. It is a thing.

[Brief description of drawings]

FIGS. 1, 2, and 3 are views showing different embodiments of the present invention, and FIG. 4 is a view showing a conventional device. Explanation of symbols 1 ... Static mixer, 2 ... Refrigerant storage tank, 3
...... Heating element, 4 ... Pump, 5 ... Control valve, 6 ... Valve,
7 ... Cooler, 9 ... Temperature detector, 10, 11 ... Valve, 12 ...
… Mold, 13 …… Valve, 14 …… Discharge pipe, 15a, 15b …… Shock absorber, 16 …… Water pipe, 17 …… Cooling pipe, 18a …… Primary cooling pipe, 18b …… Secondary cooling pipe , 19 …… heater, 21 …… heat exchanger.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Ono 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (56) Bibliographic references Sho 41-18868 (JP, Y1)

Claims (3)

[Claims] 1. A pump for pumping a refrigerant, which is provided on an upstream side of a mold used for molding a synthetic resin, a refrigerant storage tank provided on a suction side of the pump, and a cooling branched from a discharge side of the pump. The cooler provided in the pipe, and the temperature of the refrigerant,
In the mold temperature controller composed of a system for detecting and controlling the flow rate, the refrigerant storage tank is equipped with a temperature fluctuation buffer, and the refrigerant that has passed through the cooler is stored in the mold from the mold. A mold temperature control device, characterized in that the mold temperature control device is connected in a path of a refrigerant which returns to a position immediately before a suction port of a pump through a tank. 2. A temperature control valve is provided in a cooling pipe connecting the cooler and a portion of the pipe for sending the refrigerant from the tank to the pump immediately before suction to the pump, and the control valve is provided on the downstream side of the pump, and The mold temperature controller according to claim 1, wherein the mold temperature is controlled by the temperature of the refrigerant at a position before the entrance of the mold. 3. A discharge pipe connecting the mold and the tank is connected with a cooling pipe from the cooler, the cooling pipe having a valve,
The mold temperature controller according to claim 1, characterized in that a static mixer is provided between the connecting point and the tank.