JPH0335091B2 - - Google Patents

Description

Detailed Description of the Invention The present invention was made to obtain high quality molded products by keeping the temperature of the mold within a predetermined range. By supplying a cooling medium or a heating medium to the mold, and by supplying the cooling medium from a cooling tower, well or water supply via a liquid pump, the cooling effect is improved, and the structure is simple and efficient, and it can be used in extremely large quantities. In other words, when molding plastic materials, the temperature of the mold is detected, the valve is switched according to the temperature, and if the temperature of the mold is higher than the set temperature, the cooling medium is supplied from the cooling tower, well, or water supply. The cooling medium is supplied to the mold via a heater that does not generate heat and a liquid pump, and when the temperature of the mold is lower than the set temperature, the cooling medium from the cooling tower, well, or water supply is supplied to the mold. While applying pressure to the suction side of the heater and the liquid feeding pump, the new cooling medium is prevented from flowing in from the cooling tower, well or water supply, and the heating medium installed in the middle of the liquid feeding pipe is used to prevent the new cooling medium from flowing in. A method for controlling a mold temperature, which is characterized by heating a cooling medium that has been in the mold and supplying the heating medium to the mold via the liquid feeding pump to maintain the mold temperature within a predetermined range, and using the method. In other words, it is an optimal device for connecting a liquid feeding pipe led from a cooling tower, well or water supply to the liquid feeding port of a mold for molding plastics, and connecting a liquid feeding pipe led from a cooling tower or a drain to the liquid draining port of the mold. Connect the drain pipe led to
A heater and a liquid sending pump are provided in the middle of the liquid sending pipe, and one end of a branch pipe is connected to the middle of the liquid draining pipe,
The other end of the branch pipe is guided to the heater, and an electromagnetic switching valve is provided in the middle of the drain pipe to switch to the downstream side of the drain pipe or the branch pipe side, and This mold temperature control device is characterized in that the electrical output of a provided temperature detector is connected to an electromagnetic switching valve and a heater via a temperature control device.

In recent years, the demand for molded products of plastics, rubber, etc. has increased, and when manufacturing these products, temperature control of molds for molding has become essential in order to obtain high quality and high work efficiency. This temperature control is generally achieved by providing a flow path in the mold and flowing a cooling medium through this flow path.Water, which has excellent heat exchange ability and is inexpensive, is usually used as the cooling medium. It is being

Furthermore, there is a conventionally known temperature control device shown in FIG. To explain this according to the diagram, 1 is a mold, 2 is a cooling tower which is a cooling medium source, and other cooling medium sources include cooling water sources such as wells and water pipes. Instead of being circulated, the used cooling water is drained into a drain (not shown). Cooling water from the cooling tower 2 is sent through a liquid feed pipe 3, passes through an electromagnetic switching valve 4, a cooler 5, a drain pipe 6, and is returned to the cooling tower 2 for circulation. On the other hand, the water in the water tank 7 is sent to the liquid feed port 1' of the mold 1 via the cooler 5, the heater 8, and the liquid feed pump 9.
The liquid is returned to the cooler 5 through the drain port 1''. In the figure, 10 is a temperature sensor, which is installed at one of a, b, and c, and the output terminal of the temperature sensor 10 is used to adjust the temperature. It is connected to an electromagnetic switch 12 of four electromagnetic switching valve circuits and an electromagnetic switch 13 of eight heater circuits through a container 11. Reference numeral 14 is a circulation pipe, and 15 is a water supply and air hole.

In the case of this conventional example, the temperature of the mold 1 is set in advance so that the temperature controller 11 operates within a predetermined range, and when the temperature of the mold 1 is lower than the set temperature, the temperature controller 11 operates to control the electromagnetic switching valve 4. is closed, the heater 8 is energized, the heated water circulates as indicated by the thin arrow, and heats the mold 1. Furthermore, when the temperature of the mold 1 is higher than the set temperature, the electromagnetic switching valve 4 opens, cooling water from the cooling tower 2 circulates as shown by the thick arrow, and the cooler 5 is activated, and at the same time, the power to the heater 8 is cut off. The water from the water tank 7 is cooled by the cooler 5, and circulates as shown by the thin arrow through the heater 8, which does not generate heat, and the liquid feed pump 9, thereby preventing the temperature of the mold 1 from rising.

However, in this conventional example, a cooler operated by cooling water sent from a cooling tower removes the heat from the water passing through the mold and cools the water sent to the mold. The mold is indirectly cooled by two cooling water systems: and one for operating the cooler. For this reason, the temperature of the water that cools the mold is always higher than the cooling water from the cooling tower, resulting in a small cooling effect and a narrow range of temperature control, and as mentioned above, the structure is complicated due to the use of two cooling water systems. However, because the entire equipment is large and there are many devices, the amount of water used to cool the mold is large, causing a time delay in heating and cooling, and if the water decreases due to evaporation or leakage, the water The tank must be reinforced from the outside, and to do this automatically requires additional equipment, which has the disadvantage of being expensive.

Note that the air hole 15 is necessary because if the water tank is sealed, it becomes impossible to operate, and conversely, evaporation occurs because of this air hole.

The present invention eliminates these disadvantages and can provide many other effects.Next, an apparatus for using the method of the present invention will be described with reference to FIG.

A liquid feed port 1' of a mold 1 for molding plastics and a cooling tower 2 which is a cooling medium source are connected by a liquid feed pipe 3, and a heater 8 and a liquid feed pump 9 are provided in the middle of the liquid feed pipe 3. Drain port 1″ of mold 1 and cooling tower 2
are connected by a drain pipe 6, an electromagnetic switching valve 4 is provided in the middle of the drain pipe 6, a branch pipe 6' is guided from between the electromagnetic switching valve 4 and the drain port 1'', and the branch pipe 6' is A check valve 16 is provided in the middle, and the branch pipe 6' is guided to the heater 8. A temperature detector 10 such as a thermistor is provided to one of a, b, and c, and its output terminal is connected to the temperature controller 11. It is connected to the electromagnetic switch 12 of the 4-circuit electromagnetic switching valve and the electromagnetic switch 13 of the 8-circuit heater.Although the temperature sensor 10 is directly installed at one of a, b, and c, Detecting the temperature of the heat exchange medium at positions a and b ultimately also means detecting the temperature of the mold.Also, in this specific example, the cooling tower 2 is used as the cooling medium source, and the cooling water is circulated. However, it may be a well or a water supply, and in the case of a well or a water supply, the drain pipe 6 is led to a discharge groove (not shown) without being circulated.

Next, the method of the present invention will be explained using the above-mentioned inventive device. First, the temperature controller 11 is set to obtain a mold temperature convenient for molding the desired plastic material.
On the other hand, if the cooling tower 2 is operated to send cooling water as a cooling medium to the liquid feed pipe 3 and the liquid feed pump 9 is operated, the cooling water will circulate through the mold 1 and from the liquid drain pipe 6 to the cooling tower 2. Now, when the temperature detector 10 detects a temperature lower than the set temperature, the temperature regulator 11 operates, the electromagnetic switch 12 opens and the electromagnetic switching valve 4 closes, and the electromagnetic switch 13 closes to energize the heater 8. and develops a fever. For this reason, the cooling water that has already flown in is heated by the heater 8, and this heated water, that is, the heating medium is transferred to the liquid flow hole 1 of the mold 1.
a, heats the mold 1, and circulates as shown by the dotted arrow. At this time, water pressure from the cooling tower 2 is applied to section d, but since the electromagnetic switching valve 4 is closed, new cooling water will not flow into the device from section d, and no new cooling water will flow into section e. Water inside the device will not leak out. Next, when the temperature of the mold 1 reaches the set temperature, the electromagnetic switch 13 is opened by the action of the temperature regulator 11, and the electricity to the heater 8 is cut off. As a result, the temperature of the heated water decreases, and this water continues to circulate as shown by the dotted arrow. When the mold 1 reaches a predetermined temperature in this manner, the heated and molten molding material is injected into the mold 1 and a molding process is performed. When the temperature of the mold 1 rises due to the injection of high-temperature material, an electrical output is generated in the temperature sensor 10, and the temperature regulator 11 is activated to turn on the electrical switch 1.
2 is closed, the electromagnetic switching valve 4 is opened, and the cooling water is circulated as indicated by the solid line arrow, thereby suppressing the temperature of the mold 1 from rising. Thereafter, the electromagnetic switching valve 4 is opened and closed by the operation of the temperature regulator 11, and the temperature of the mold 1 is maintained at the set value. In addition, since the branch pipe 6' is provided with a check valve 16, the cooling water from the cooling tower 2 does not enter the heater 8 and is not suddenly injected into the drain pipe 6, and the electromagnetic switch 12 controls the temperature. When the temperature of the mold 1 rises above the set temperature due to the function of the regulator 11, it closes and opens the electromagnetic switching valve 4, and when the temperature is within the set temperature or lower than the set temperature, it opens and closes the electromagnetic switching valve 4. The electromagnetic switch 13 closes and energizes the heater 8 when the temperature falls below the set temperature due to the action of the temperature regulator 11, and opens to cut off the energization to the heater 8 when the temperature is within or above the set temperature. .

As described above, in the method of this invention, when the temperature of the mold is higher than the set temperature, water for mold cooling cooled by the cooler as in the conventional method, that is, water that is higher temperature than the cooling medium for operating the cooler, is sent to the mold. Since the cooling medium is supplied to the mold from a cooling tower, well or water supply rather than from a cooling tower, a well or water supply, a very good cooling effect can be achieved with simple means, and in both cases where cooling and heating are required. Also the cooling tower to the suction side of the liquid pump through the heater,
Since pressure is applied from a well or water supply, it can compensate for the lack of pressure of the cooling medium to the mold when cooling is required, and when heating is required, it can be used with a heater that tends to occur when the temperature is high. Boiling on the surface and cavitation phenomenon occurring inside the pump can be prevented, and the durability of the heater and pump can be increased.

In addition to the above-mentioned effects, the device of this invention has a simple structure, so it can be downsized and manufactured at low cost.
Only a small amount of heating medium is required, and heating and cooling responses are faster.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of this invention, and FIG. 2 is an explanatory diagram of a conventional example. 1...Mold, 1'...Liquid feeding port, 1''...Liquid drain port,
2...Cooling tower, 3...Liquid pipe, 4...
Solenoid switching valve, 6... Drain pipe, 6'... Branch pipe, 8
... Heater, 9 ... Liquid pump, 10 ... Temperature detector, 11 ... Temperature regulator.

Claims (1)

[Claims] 1. Detecting the temperature of a mold when molding a plastic material,
The valve is switched depending on the temperature, and if the temperature of the mold is higher than the set temperature, the cooling medium is sent from the cooling tower, well or water supply to the liquid pipe, and the cooling medium is passed through a heater that does not generate heat and a liquid sending pump. When the temperature of the mold is lower than the set temperature, the pressure of the cooling medium from the cooling tower, well or water supply is applied to the suction side of the heater and the liquid sending pump, and the pressure of the cooling medium from the cooling tower, well or water supply is applied to the suction side of the heater and the liquid sending pump. Preventing the inflow of a new cooling medium, and heating the cooling medium that has already flowed in by the heater installed in the middle of the liquid feeding pipe, and supplying this heating medium to the mold via the liquid feeding pump. A mold temperature control method characterized by keeping the mold temperature within a predetermined range. 2. Connect a liquid feed pipe led from a cooling tower, well, or water supply to the liquid feed port of a mold for molding plastics, and connect a liquid feed pipe led to a cooling tower or drain groove to the liquid drain port of the mold. a heater and a liquid pump are provided in the middle of the liquid pipe, one end of a branch pipe is connected in the middle of the liquid drain pipe, the other end of the branch pipe is led to the heater, An electromagnetic switching valve is provided in the middle of the drain pipe to switch to the downstream side of the drain pipe or the branch pipe side, and the electrical output of the temperature sensor provided in the mold or the feed pipe or the drain pipe is controlled by a temperature controller. A mold temperature control device, characterized in that it is connected to an electromagnetic switching valve and a heater through an electromagnetic switching valve and a heater.