JPH1054763A - Light receiving part of optical temperature measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the visual field of an optical temperature measuring device from evaporated matter caused from ground metal being melted in a vacuum fusion furnance. SOLUTION: The light receiving part of the optical temperature measuring device has a cylindrical outside electrode 11 and a gas-permeable inside electrode 12, and the outside electrode 11 and the inside electrode 12 are arranged in concentrically, and DC voltage is applied, and a device 10 for securing a visual field and directing this concentric axial center into a crucible 1 is disposed inside a glass window 5 of a bell jar 3 and evaporated matter caused from the ground metal 6 is made to deposite onto the inner surface of the outside electrode 11 to prevent cloud of the glass window 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving portion of an optical temperature measuring device used in a vacuum melting furnace, and more particularly, to secure a view of the temperature measuring device from evaporation generated from a melting metal. It is composed.

[0002]

2. Description of the Related Art In order to obtain a metal material which is practically used in industry, a base metal is mixed and melted, and in order to form a predetermined ingot, the base metal placed in a crucible is subjected to high-frequency electric power in a vacuum. Conventionally, a vacuum melting furnace for melting an alloy to form an alloy has been used.

A conventional vacuum melting furnace, as shown in FIG.
It comprises a coil 2 to which high-frequency power is applied, a crucible 1 arranged in the coil 2, and a bell jar 3 for maintaining a vacuum.

When the metal 6 to be melted is placed in the crucible 1 and high-frequency power is applied to the coil 2 while evacuating the air in the bell jar 3, the metal 6 is melted by induction heating. In this melting step, an optical thermometer is used to non-contactly measure the temperature of the base metal 6.

[0005]

However, the light emitted from the metal 6 in the crucible 1 is received outside the bell jar 3 through the glass window 5 and made incident on the optical thermometer 4 to measure the temperature. However, the evaporant such as black smoke generated from the metal 6 by heating fills the bell jar 3, the glass window 5 also becomes cloudy gradually, and the entire spectrum of the light emitted from the metal 6 is measured by an optical thermometer. As a result, it is not possible to receive light correctly, so that accurate temperature measurement cannot be performed.

Therefore, the present invention has been conceived to solve such a problem and to secure a view of an optical thermometer.

[0007]

The light receiving portion of the optical temperature measuring device according to the present invention includes a cylindrical outer electrode and a permeable inner electrode, and the outer electrode and the inner electrode are concentrically arranged. A device for ensuring a visual field in which the concentric axis is directed into the crucible is provided inside the glass window of the bell jar.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a melting furnace has a coil 2 to which high-frequency power is applied, a crucible 1 disposed in the coil 2, and a vacuum having a glass window 5. And the bell jar 3.

According to the present invention, in the bell jar 3, a glass window 5 is provided at a position where a light beam emitted from the metal 6 of the crucible 1 can be received, for example, at the top, and a field of view of the optical thermometer 4 is provided inside the glass window 5. Is provided.

As shown in the perspective view of FIG. 2, the device 10 for securing the visual field includes a cylindrical outer electrode 11 and a plurality of rings 13.
Are arranged at intervals via a spacer 14.
The outer electrode 11 and the inner electrode 12 are arranged concentrically, and this concentric axis is directed into the crucible 1.

Then, lead wires are drawn out from the outer electrode 11 and the inner electrode 12 and connected to a DC power source.
When a high DC voltage is applied during the operation, it operates in the same manner as the Cottrell dust collector, and evaporates generated from the metal 6 are removed from the outer electrode 11.
To prevent fogging of the inner surface of the glass window 5 of the bell jar 3.

Since the DC voltage applied to the outer electrode 11 and the inner electrode 12 has a low atmospheric pressure in the bell jar 3, the purpose can be achieved with a relatively low voltage.

The light emitted from the metal 6 is applied to the inner electrode 12.
When the light is received by the optical thermometer 4 through the ring 13, the inner surface of the glass window 5 of the bell jar 3 does not fog, so that the entire spectrum of the light emitted from the metal 6 can be correctly received.

In the above-described embodiment, the inner electrode 12 in which the plurality of rings 13 are arranged at intervals with the spacer 14 interposed therebetween is used. Alternatively, electrodes of other shapes that allow the electric field to fully reach the center may be used.

[0015]

As is clear from the description based on the above embodiment, according to the light receiving portion of the present invention, the temperature of the metal being melted in the vacuum melting furnace can be continuously and accurately measured by the optical temperature measuring device. Can be measured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a light receiving section of an optical temperature measuring device according to the present invention;

FIG. 2 is a perspective view of a device for securing a visual field in the device shown in FIG. 1;

FIG. 3 is a longitudinal sectional view showing a conventional melting furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crucible 2 Coil 3 Bell jar 4 Optical thermometer 5 Glass window 6 Ingot 10 Device to secure a field of view 11 Outer electrode 12 Inner electrode 13 Ring 14 Spacer

Claims (1)

[Claims] 1. A crucible comprising: a cylindrical outer electrode; and a permeable inner electrode, wherein the outer electrode and the inner electrode are arranged concentrically, and the concentric axis is directed into the crucible. A light receiving section of the optical temperature measuring device, wherein a device for securing a visual field is provided inside the glass window of the bell jar.