JPH028023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum deposition furnace that can instantly change the desired plating amount.

Among the evaporation sources for continuously vacuum-depositing metal films such as Zn and Al on steel strips, etc., the deposition furnace currently being considered as an upper-heating method has the structure shown in Figure 1. .

In Fig. 1, 4 is a steel strip, 2 is a vacuum container, and 3 is a steel strip.
1 is a vapor deposition pot, 4 is a heater, 5 is a molten metal as plating material, 6 is a vapor deposition port, 7 is a heat insulating material, 11 is a snorkel, and 12 is a melting furnace.

A vapor deposition pot 3 placed in a vacuum container 2 holds a plating material 5 therein, and the plating material 5 is heated by a heater 4 to evaporate, and is ejected from a vapor deposition port 6 to form a layer above the plating material 5. The steel strip 1 that is traveling is continuously plated.

The plating material 5 is melted in advance in the melting furnace 12 and then sucked up into the vapor deposition pot 3 via the snorkel 11 due to the pressure difference.

Such conventional vapor deposition furnaces have the following drawbacks.

For example, when the thickness of the supplied steel strip changes, you may want to instantaneously change the amount of plating on the steel strip, but because the heat capacity of the plating material in the deposition furnace and the furnace itself is large, Even if the heating amount of the heating source is changed instantaneously, the response of the evaporation rate of the plating material is delayed, and by the time it stabilizes, a product with a non-standard basis weight is produced.

The present invention eliminates these drawbacks and provides a vacuum deposition furnace that can instantaneously change the desired amount of plating on a steel strip.

That is, the present invention relates to a vacuum evaporation furnace having a heat source heater above the furnace, characterized in that a rotatable heat input control plate is provided between the heat source heater and the bath surface. It is something.

FIG. 2 is a diagram showing an embodiment of the vapor deposition furnace of the present invention.

In Fig. 2, the same symbols as in Fig. 1 indicate the same functional parts as in Fig. 1, and the difference from Fig. 1 is the heater 4.
A heat input control plate 9 that can rotate about a rotating shaft 8 is provided between the plating material 5 and the plating material 5.

The rotating shaft 8 and the heat input control plate 9 are driven by a drive mechanism (not shown) provided on the furnace side.

In FIG. 2, during steady operation, the heat input control plate 9 is held at a certain opening degree (for example, at a position of 45 degrees with respect to the horizontal).

If you want to change the evaporation rate, change the heater power of the heater 4 instantaneously (for example, increase it), and at the same time change the opening degree of the heat input control plate 9 (open, that is, remove the metal from the heater 4). increase the effective irradiation area on the material 5).

Once the evaporation rate has been stabilized, the heat input control plate 9
Gradually return to the original opening.

The controllability of the evaporation rate at this time will be schematically explained with reference to FIG.

In Fig. 3, A indicates the opening degree of the heat input control plate 9, and B indicates the heater power of the heater 4 (1), (2), respectively.
(3) and (4) indicate that the changes are made in the manner of (3) and (4).
C, D, and EF are the outer surface temperature of the heater (there is a temperature distribution in the circumferential direction and its average temperature is shown) according to this change, the heat input D to the plating material 5, the surface temperature E of the plating material 5, and the evaporation rate. F is (1), (2), (3), (4) respectively
This indicates that the change occurs in the following manner.

First, (1) in FIG. 3 is a case where the opening degree A of the heat input control plate 9 is kept constant and only the heater power B of the heater 4 is changed in steps, and the heater outer surface temperature C is the same as that of the heater 4 and the furnace. Due to the heat capacity of the body 2, it responds with a first-order lag, and therefore the heat input D to the plating material 5 also changes with a first-order lag, and along with this, the surface temperature E of the plating material 5 and the evaporation rate F change with a first-order lag. Shows a similar response.

Next, (2) in FIG. 3 is a case where the heater power B of the heater 4 is kept constant and only the opening degree A of the heat input control plate 9 is changed in steps, and the heater outer surface temperature C is the above ((2)). As in case 1), it responds with a first-order lag, and the heat input D to the plating material 5 also responds with a first-order lag, but since the heater power B remains constant, the value after settling is the same as before the change. Become. The surface temperature E and evaporation rate F of the plating material 5 also show substantially the same response as the heat input D to the plating material 5.

(3) in Figure 3 is the heater power B of the heater 4.
This is a case where the opening degree A of the heat input control plate 9 is simultaneously changed in steps, and the heat input D to the plating material 5 and the surface temperature E of the plating material 5 show a response close to a step change as shown in the figure. If the opening degree A of the heat input control plate 9 is gradually returned to its original value in stages as shown in the figure, this corresponds to the case where only the opening degree of the heat input control plate 9 is changed in steps in (2) above, so the evaporation rate F responds as shown.

(4) in Figure 3 is the heater power B of the heater 4.
This is a case where the opening degree A of the heat input control plate 9 is changed in steps at the same time, and then the opening degree A of the heat input control plate 9 is continuously and smoothly returned to the original value. As in the case of ), the value changes stepwise, but after that, the stepwise change as in (3) above is not shown, and the changed value is maintained as is as shown in the figure.

In this way, the heater power B of the heater 4 and the opening degree A of the heat input control plate 9 are changed in steps at the same time, and after the desired evaporation rate is established, the opening degree of the heat input control plate 9 is changed as shown in FIG. If the evaporation rate F is returned to its original state continuously and smoothly as shown in (4), the evaporation rate F can be changed without delay in response to changes in the heater power B.

As is clear from the detailed description above, the deposition furnace of the present invention can instantly change the amount of plating on a steel strip, etc., and is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional vacuum deposition furnace, FIG. 2 is a diagram showing an embodiment of the deposition furnace of the present invention, and FIG. 3 is a diagram for explaining the effects of the deposition furnace of the present invention.

Claims (1)

[Claims] 1. A vacuum deposition furnace having a heating source heater above the furnace, characterized in that a rotatable heat input control plate is provided between the heating source heater and the bath surface.