JPH0427006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hot plate cooling mechanism for a hot press for resin molding.

(Prior art and its problems) When molding resin using a hot press, hot plates are heated with steam, heat medium oil, electric heaters, etc., and then cooled with heat medium oil, water, etc. Then, the resin will be molded.

Generally, the molding temperature of resin is about 120 to 220℃, and when heat transfer oil is used as a refrigerant, the sensible heat of the oil is used, so the hot plate temperature can be uniformly cooled, and the resin can be cooled uniformly, making it easier to mold. Although favorable results can be obtained, equipment costs are high, and if used in large quantities, measures must be taken according to the Fire Service Act.

On the other hand, cooling a hot plate with water utilizes the latent heat of the water, which causes rapid cooling from the inlet of the water, resulting in large temperature irregularities during cooling, and it is impossible to control the cooling rate, so it is difficult to control the type of resin. Although this may result in undesirable molding depending on the situation, it is usually used because the equipment cost is low.

However, recently, various resins have been developed, and the molding temperature
Products that can reach temperatures of 400℃ are becoming possible. Heat plates that can handle this use a method that uses an electric heater as the heat medium and compressed air, saturated steam, or spray water as the refrigerant. There is a large temperature difference between
It is disadvantageous in terms of cost. Note that heat transfer oil cannot be used at high temperatures due to thermal decomposition.

(Object of the Invention) In view of the above circumstances, the present invention enables the use of cooling water from the initial stage of cooling the hot plate, is advantageous in terms of equipment and cost, and enables uniform cooling of the hot plate. The purpose is to provide a hot plate cooling mechanism for a hot press that enables arbitrary cooling according to conditions.

(Structure of the Invention) For the above purpose, the hot press hot plate cooling mechanism according to the present invention includes a metal pipe fitted into a bore hole formed in the hot plate main body, and a cooling medium inside the metal pipe. The heat capacity of the metal pipe is set to be smaller than the heat capacity of the hot plate body.

According to the above configuration, a metal pipe having a smaller heat capacity than the hot plate body is interposed between the hot plate body and the cooling medium, and the metal pipe and the cooling medium introduced into the cooling medium passage in the metal pipe are interposed between the hot plate body and the cooling medium. The heat transfer efficiency between the metal pipe and the hot plate body is high, and the heat transfer efficiency between the metal pipe and the hot plate body is low because it is through the fitting contact surface between the two.
As a result, the cooling medium introduced into the cooling medium passage in the metal pipe first rapidly cools the metal pipe, which has a smaller heat capacity than the hot plate body, to around the coolant temperature, and then the metal pipe receives the heat of the hot plate body. The hot plate body is cooled by being transmitted through the fitting contact surfaces of the two. For this reason, by circulating the coolant at a predetermined flow rate through the coolant passage inside the metal pipe, the metal pipe is uniformly maintained near the coolant temperature, and this uniformly cooled metal pipe As a result, the hot plate body is gradually cooled as the heat is transferred, and the hot plate is cooled evenly throughout the cooling medium passage without being suddenly cooled only at the inlet portion of the cooling medium passage. The temperature difference between the outlet and inlet sides can be reduced.

(Embodiment of the Invention) The illustrated hot plate 1 has metal pipes, for example, stainless steel pipes 3, fitted into a plurality of bored holes 2 formed through the holes at approximately equal intervals in a predetermined direction.
Each stainless steel pipe 3... is connected to the hot plate 1 as shown in the first diagram.
are connected to each other on the outside to form a meandering cooling water passage 4 having a cooling water inlet 5 and a cooling water outlet 6. Here, the heat capacity of the stainless steel pipes 3 forming the cooling water passage 4 is extremely small compared to the heat capacity of the main body portion of the hot plate 1.

In the hot plate configured in this way, the cooling water as a cooling medium introduced from the cooling water inlet 5 is divided into left and right sides as shown by the arrows in FIG. The water flows in a meandering manner through the cooling water passage 4, joins together again just before the cooling water outlet 6, and then flows out from the cooling water outlet 6.

When the cooling water flows into the cooling water passage 4, the stainless steel pipe 3, which has a small heat capacity, is rapidly cooled down to almost the temperature of the cooling water, and then the inner wall of the borehole 2 and the stainless steel pipe 3 are cooled down.
Heat exchange is performed with the outer wall, and the hot plate 1 is cooled. Therefore, heat is exchanged indirectly between the hot plate 1 and the cooling water via the stainless steel pipe 3.

Since the stainless steel pipe 3 interposed between the hot plate 1 and the cooling water has a small heat capacity, the amount of heat that this stainless steel pipe 3 has is extremely small compared to the amount of heat that the entire hot plate has. Even if the amount of heat possessed by the stainless steel pipe 3 is rapidly transferred to the cooling water in direct contact through the inner wall surface of the stainless steel pipe 3, the temperature of the cooling water can be lowered by circulating the water at a flow rate that can absorb it as sensible heat. 4
The cooling water is discharged from the cooling water outlet 6 without rising rapidly. Therefore, the difference in cooling water temperature between the cooling water inlet 5 side and the cooling water outlet 6 side of the hot plate 1 becomes small, and the entire hot plate 1 can be cooled substantially uniformly.

Furthermore, since the cooling rate is faster than compressed air cooling or steam cooling, and the cooling rate can be easily controlled, the heating/cooling cycle time of the hot plate 1 can be shortened.

(Effects of the Invention) According to the hot press hot plate cooling mechanism of the present invention as described above, it is possible to cool the hot plate substantially uniformly, so that the molding cooling temperature of the resin is also uniform, and good resin molding is possible. Become.

In addition, since it is sufficient to supply ordinary cooling water as a cooling medium, special cooling equipment or the like is not required, which is advantageous in terms of cost.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention;
FIG. 2 is a sectional view of the cooling water passage. 1... Hot plate, 2... Boring hole, 3... Stainless steel pipe (metal pipe), 4... Cooling water passage, 5... Cooling water inlet, 6... Cooling water outlet.

Claims (1)

[Claims] 1 A metal pipe is fitted into a bore hole formed in the hot plate body, and the inside of the metal pipe is used as a cooling medium passage, and the heat capacity of the metal pipe is smaller than the heat capacity of the hot plate body. A hot press hot plate cooling mechanism characterized by: