JPH0520671B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for manufacturing a heat insulating box, and in particular, a four-point injection method that significantly reduces the amount of heat insulating material used, and a foaming gas injection method that forcibly reduces the pressure at that time. The present invention relates to a heat insulating box suitable for ensuring stable fluidity of a heat insulating material by effectively discharging water.

[Background of the invention]

In conventional insulation boxes, insulating material (for example, urethane) is injected at an angle, with the ceiling facing down and the machine room facing up, as it is necessary to keep the back surface clean. An inlet was provided in the machine room, and injection ports were provided at two points, one on the hinge side and the other on the handle side, for injection.

However, with this method, although the final filling part is stabilized, the fluidity is extremely reduced, which increases the formation of skin layers on the outer panel and inner box, and increases the amount of injection.
As a result, there were drawbacks such as the inner box made of plastic such as ABS being exposed to chemical attack and the outer box blistering.

[Purpose of the invention]

The purpose of the present invention is to significantly reduce the injection amount by reducing the formation of a skin layer and improving fluidity in a method for injecting heat insulating material into a heat insulating box.
To provide a heat insulating box body which can reduce chemical attack on the inner box made of plastic such as ABS and further reduce the swelling of the outer box.

[Summary of the invention]

Conventionally, in the case of inclined two-point injection consisting of an injection port and a gas discharge port provided in a machine chamber, flow resistance becomes large, resulting in the formation of a skin layer, resulting in a large injection amount. Therefore, in order to solve these problems, it was necessary to shorten the flow distance as much as possible, but in order to do this, it was necessary to change the injection position from an inclined to a horizontal position, and to do so from two points, one in the machine room and one in the ceiling, as long as it did not damage the appearance. By using four points instead of two, the flow distance can be further shortened. However, in this method, the final filling part is concentrated in the center of the back, so foaming gas tends to remain.Therefore, the present invention allows the gas to be efficiently and forcibly discharged from the gas outlet provided in the center of the inner box. I was able to achieve my goal.

〔Example〕

The details of the present invention will be explained below with reference to FIGS. 1 to 3. 1 is an outer box assembly, 2 is an inner box, 3 and 4 are conventional machine room nozzles and their injection ports 3' and 4' are ceiling nozzles and their injection ports combined with 3 and 4 according to the present invention. It is. 5 is a conventional machine room gas exhaust port, and 6 and 7 are gas exhaust mats and vacuum pads used for forced exhaust according to the present invention. 8 indicates a heat insulating material (urethane stock solution), and 9 indicates the flow direction of the stock solution.

To explain the method of manufacturing the heat insulating box of the present invention, conventionally, the opening is placed on the bottom, the ceiling is on the bottom and the machine room is on the top. When injecting the insulation material from the insulation injection nozzle 3 into the injection port 4, which is so-called inclined injection, the insulation material 8 hits the outer box assembly 1 and falls.
The foaming gas is discharged in the direction of the final filling part along the flow direction 9 of the stock solution, and the foaming gas is discharged from several tens of discharge holes 1 to 3φ in diameter as discharge ports 5 on the back surface as shown in FIG. The present invention has its insulation material injection nozzle completely horizontal, as shown in FIGS.
As shown in the figure, in addition to the left and right parts near the machine room, the insulation material injection nozzle 3 and the injection port 4 are installed in the left and right parts near the ceiling, and the injection nozzle 3 near the machine room and the injection nozzle near the ceiling are installed. Injection is started from 3' at the same time. Furthermore, the present invention is provided with a device for forcibly discharging foaming gas near the final filling part, and a gas exhaust mat 6 is provided on the side of the insulation material near the center of the inner box 2, and on the side opposite to the insulation material. 3 seconds after the insulation material is injected from the vacuum pump through the vacuum pad 7, suction is started.
For example, a motor-driven automatic valve or a pressure indicator is used to adjust the bubbling pressure generated by the reaction to 0 atmospheres.

The gas outlet was installed near the center of the back of the inner box for injection at four points: on the left and right near the machine room, and on the left and right near the ceiling.Moreover, if the gas is injected horizontally, the flow distance will be extremely shortened. This is because the foaming gas tends to remain, impeding fluidity and causing whitening of the inner box, so it became necessary to forcibly remove it.

In addition, we set the suction start time by the vacuum pump to 3 seconds after injecting the insulation material, which is within a range that does not harm the formation reaction of the insulation material, and the fluidity is the best when the reduced pressure is balanced around 0 atmospheres. improves.
According to this example, by combining the four-point injection method and the forced degassing method, the fluidity of the insulation material is further improved, and residual gas other than bubble formation can be eliminated, resulting in a significant reduction in the amount of insulation material used. This also prevents the inner box from becoming white.

〔Effect of the invention〕

According to the present invention, the injection ports are provided on the back side of the outer box near the machine room and on the left and right parts near the ceiling, and the gas exhaust port equipped with a gas exhaust mat is provided near the center of the back side of the inner box. This reduces the flow distance of the insulation material, eliminates the retention of foaming gas, and improves the fluidity of the insulation material, especially at the corners, which reduces the amount of insulation material used. Since the bulge of the outer box is improved, demolding time can also be significantly improved. What's more, the whitening of the plastic inner box is eliminated, and the tape used to prevent whitening can be removed and the number of people involved in processing can be reduced.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the back of the refrigerator insulation box, Figure 2
The figure is a sectional view taken along line A-A in Figure 1, and Figure 3 is B in Figure 1.
-B sectional view. 1... Outer box gift, 2... Inner box, 3... Machine room injection nozzle, 3'... Ceiling injection nozzle, 4...
Machine room inlet, 4'...Ceiling inlet, 5...
Machine room gas exhaust port, 6...Gas exhaust mat, 7
...Vacuum pad, 8...Insulation material (urethane stock solution),
9... Direction of flow of stock solution.

Claims (1)

[Claims] 1. An outer box, an inner box made of plastic, and a foamed insulation material filled in a space formed between the two boxes, wherein the insulation material is injected into the outer box before foaming. In an insulated box body having an injection port for injecting a liquid, the injection port is provided on the rear side of the outer box near the machine room and on the left and right parts near the ceiling, and the injection port is provided near the center of the back side of the inner box. A heat insulating box body characterized by being provided with a gas exhaust port equipped with a gas exhaust mat.