JPS621327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutter mechanism for cutting and stopping outflow glass.

In order to more safely process and dispose of high-level radioactive waste, it is possible to contain it in vitrified materials.
It is being studied and implemented in many countries. In the process of producing this vitrified material, it is extremely important and effective to allow the glass to flow out safely from the melting furnace where it is melted together with radioactive waste, and to stop the outflow. However, conventionally established methods have not yet been developed.

However, since the melting temperature of glass is extremely high, it is impossible to cause or stop the glass from flowing out of the glass melting furnace by opening and closing operations using normal valves. Therefore, a method has been proposed in the past in which the molten glass is removed from the container by tilting the container, pouring it out, returning it to the horizontal position, and stopping the container. Not suitable for melting furnaces. Generally, a nozzle is often provided in the lower part of the melting furnace to flow out the molten glass. When glass is first stored and melted in this melting furnace, and when molten glass is discharged and discharged, it is necessary to open and close the nozzle by some method. A known method for opening and closing this nozzle is the so-called freeze valve method, in which the nozzle body is heated or cooled to flow out (dissolve) and stop (solidify). However, when stopping the outflow with a freeze valve, it is necessary to cool the nozzle to solidify the glass, but the outflowing glass cannot be cooled instantly, and as it is gradually cooled, the viscosity increases and it gradually flows out. The speed slows down and eventually it solidifies and the outflow stops. During this process, there is a drawback that a stringing phenomenon occurs in which the glass hangs down from the lower end of the nozzle in a thin string-like state and hardens. In order to prevent this stringing phenomenon, a mechanism is currently being developed in which the flowing glass is cut with scissors-like objects from the left and right at the bottom of the nozzle, and then suppressed from the bottom with a plug-like object. Although the pulling phenomenon can be solved, the mechanism and operation are not only complicated, but also the glass scatters when cutting the glass, and it is necessary to adjust the outflow temperature of the glass to an optimum range in order to cut the glass well.

Therefore, there has been a need in the art for a mechanism for safely and easily cutting and stopping molten glass.

An object of the present invention is to provide a mechanism for safely and easily cutting molten glass and simultaneously stopping the cutting.

A further object of the present invention is to provide a mechanism for cutting and stopping molten glass from a glass melting furnace used in the vitrification of high level radioactive waste.

A more specific object of the present invention is to provide a cutter mechanism installed at the bottom of a glass melting furnace below the outflow nozzle for operating the cutting and stopping of molten glass.

Other objects and advantages of the present invention will become apparent in the following.

The cutter mechanism of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of the cutter mechanism of the present invention. 1 is a glass melting furnace containing molten glass, which melts glass by indirect heating using an electric heater or the like from the outside, direct current heating, high-frequency induction heating, etc.; The outflow nozzle 2 is arranged to face vertically downward. By heating the inside of the outflow nozzle using the heating method described above, the glass inside the outflow nozzle 2 can be melted and the glass inside the furnace can be caused to flow out. Reference numeral 3 denotes a cutter for cutting the molten glass flowing out from the nozzle at the nozzle tip, and has a cutter body having cutting teeth and an arm 4 for swinging the cutter body in the direction of the nozzle tip. This arm 4 is installed so that the center of swing of the arm is offset from the vertical axis of the nozzle. A stopper 5 is provided facing the cutter body so as to come into contact with the cutting teeth of the cutter body when the cutter body is positioned vertically below the nozzle. The first feature of the cutter mechanism of the present invention having such a configuration is that the swing center C of the arm 4 that swings the cutter 3 toward the nozzle tip is located at a position offset from the vertical axis of the nozzle. . The arm draws an arc around this swing center C, and is operated so that it is at point A when stopping the outflow glass, or at point B when it is flowing downward in the vertical direction of the nozzle. At this time, when the cutter 3 is located at point A, the cut is made so that the lower end surface of the outflow nozzle 2 and the upper surface of the cutter 3 are parallel to each other. By placing the swing center of the arm at point C, which is offset from the vertical axis of the nozzle, when the cutter is operated when stopped, the horizontal glass cutting force x and the upper pressing force y are simultaneously applied near point A. The glass flow flowing out is cut by the sharp tip of the cutter 3 and the stopper 5, and can be effectively stopped by pressing it with the upper surface. On the other hand, when re-flowing from a stopped state, the moment the cutter 3 is moved in the direction of point B, a horizontal force x' and a downward force y' are applied simultaneously, so that the peeling movement from the outflow nozzle is smooth. It can be done. (See Figure 3 which explains the movement of the cutter).

Here, the position of the center point C of the rotation axis of the cutter 3 is preferably such that the value of the angle θ formed by each point D, A, and C is in the range of 0° to 30°.
The range is from ゜ to 20゜.

A second feature of the invention is that the cutter body is cooled. There are several ways to cool the cutter body, but from the viewpoint of effectiveness and workability, the method of cooling the cutter body by passing a cooling pipe that also serves as the arm 4 inside the cutter 3 and passing a fluid such as water or air through it is preferable. The most practical. Second
The figure is a longitudinal sectional view of a cutter mechanism showing an embodiment thereof.

Furthermore, when using the cutter mechanism of the present invention, it is important to determine how to set the gap between the cutter 3 and the lower end surface of the nozzle when it is positioned vertically below the nozzle 2, that is, at point A. .

The cutter mechanism of the present invention is the second one of the present invention described above.
Due to the synergistic effect of this feature and the gap between the cutter body and the lower end surface of the nozzle, the original effects of the present invention are achieved as will be described later. As shown in Fig. 2, a fluid such as water or air is passed through the inside of the cutter 3 through a cooling pipe that also serves as an arm to cool the cutter body and stop the glass flowing out (at point A). Position) If there is a slight gap between the top surface of the cutter 3 and the bottom surface of the outflow nozzle 2, when the cutter 3 reaches point A, the glass in this gap will be in contact with the top surface of the cutter 3, cooled, and instantly solidified into
Therefore, even while the outflow of the molten glass is stopped, the molten glass will not leak out from the gap between the outflow nozzle 2 and the cutter 3. In order to have this effect, it is desirable that the gap between the lower end surface of the outflow nozzle 2 and the cutter 3 be 0.5 mm or less.
A range of 0.1 to 0.4 mm is more effective. In addition, since this gap is filled with solidified glass, the heat from the outflow nozzle 2 is not directly transferred to the cutter 3, and the glass in the outflow nozzle can be stopped without causing an extreme temperature drop. Even in the event of spillage, the feature is that by moving cutter 3 to point B, the spillage can begin immediately. Another purpose of cooling the cutter 3 is that when high-temperature molten glass comes into contact with metal, the lower the temperature of the metal, the worse the wettability of the glass to the glass, making it easier to peel off when the glass solidifies.
This characteristic is applied to the cutter 3 of the present invention, and it is desirable to cool not only the cutter 3 but also the stopper 5 and other parts of the cutter mechanism attached thereto.

In addition, when using the cutter mechanism of the present invention, there should be a space between the cutter 3 and the lower end surface of the nozzle to prevent elongation of the material, such as elongation of the nozzle due to heating, and mechanical causes, e.g. elongation due to centrifugal force of the arm. Although it is necessary to provide a clearance for this, it is sufficient that the clearance is within the above-mentioned range.

The structure and effects of the cutter mechanism of the present invention are as described above, but the effects are summarized below: (1) At any time, at the start of outflow, at the time of steady outflow, at the end of outflow, and in any outflow temperature range. However, you can stop the outflow at will.

(2) The outflow can be stopped without cooling the outflow nozzle of the glass melting furnace (while it remains heated).

(3) Mechanism and operation are simple and maintenance is easy.

(4) There is no glass scattering when the outflow is stopped.

The structure and effects of the present invention will be specifically explained below with reference to Examples.

Example (1) Specifications of experimental equipment (i) Melting furnace type: Cylindrical 100mm ID x 600mm ^L Characteristic: Inconel 600 Heating: External heating with silicon carbide (SiC) electric heater Outflow nozzle: 7.8mm ID x 150mm ^L SUS310S (ii) Cutter mechanism model: Cutter tip with cutting teeth, top surface 22mm ^L ×
28mm ^W Rotation center axis position: 15mm from the outflow nozzle center line to the stop operation side, rotation radius 80mm, θ = 10.8
゜Gap between outflow nozzle and cutter: 0.2mm Cooling water amount: 10/Hr Material: SUS304 (iii) Glass used: Borosilicate glass + 20% simulated waste Total 1
(2) Experimental method The glass slurry was placed in a melting furnace, evaporated and calcined, and then melted at 1200°C. The outflow nozzle was heated to 1000°C, the cutter was operated while glass was flowing out, and the situation of outflow and stoppage was observed.

(3) Experimental results When the outflow nozzle was heated while the temperature inside the melting furnace was maintained at 1200°C, molten glass flowed out at a temperature of approximately 820°C or higher. With glass constantly flowing out,
When the cutter was operated and moved directly below the outflow nozzle, the glass rapidly solidified on the top surface of the cutter, and the glass was able to stop flowing out from the gap with the outflow nozzle. It was also possible to maintain the stopped state of outflow while heating the outflow nozzle to 1000°C. Next, the cutter was rotated by operating the cutter again, and when the cutter was released from directly below the outflow nozzle, the glass started flowing out after about 3 seconds and flowed steadily.

By repeating the above operations, it was confirmed that the flow could be started and stopped at will without any glass scattering or stringing phenomenon.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts for explaining the structure of the cutter mechanism of the present invention. FIG. 2 is a view of only the cutter mechanism shown in FIG. 1 in the direction of the "X" arrow. FIG. 3 is a diagram for explaining the movement of the cutter shown in FIG. 1.

Claims (1)

[Claims] 1. A furnace containing molten glass and having a molten glass outflow nozzle on the bottom surface, and a cutter that cuts the molten glass flowing out from the nozzle at the tip of the nozzle. In a cutter mechanism for cutting and stopping outflow glass, the cutter has a cutter body having a cutting blade and an arm, and the arm is configured to direct the cutter body downward in the vertical direction of the nozzle when cutting the molten glass. It is characterized by comprising a horizontal arm member and a vertical arm member arranged, the center of swing of the arm is provided at the lower end of the vertical member of the arm, and the center of swing of the arm is located at a position offset from the vertical axis of the nozzle. cutter mechanism. 2. The cutter mechanism according to claim 1, further comprising a device for cooling the cutter body. 3. The cutter mechanism according to claim 1, wherein the device for cooling the cutter body is an arm that also serves as a cooling pipe. 4. The cutter mechanism according to claim 1, wherein the swing center of the arm is set such that the angle between the axis of the arm and the vertical axis of the nozzle is at most 30 degrees. 5. The cutter mechanism according to claim 1, wherein a stopper is provided facing the cutter located vertically below the nozzle and in contact with the cutting teeth of the cutter. 6. The cutter mechanism according to claim 1, wherein the gap between the upper surface of the cutter located vertically below the nozzle and the lower end surface of the nozzle is 0.5 mm or less. 7. The cutter mechanism according to claim 5, comprising a device for cooling the stopper.