JPH0146794B2 - - Google Patents

Description

[Detailed description of the invention] The present invention suspends a sample using sound waves, heats it, melts it, and
This invention relates to a mirror furnace with a sonic levitation device capable of performing solidification.

In the container-less heating, melting, and solidification processes of high-purity materials in a zero-gravity field, such as space material experiments, it is necessary to suspend the sample. Electrolevitation devices are theoretically possible.

However, electromagnetic levitation devices are limited to conductive materials such as metals and semiconductors, sonic levitation devices can be applied to dielectric materials, but require an atmospheric gas, and electrostatic levitation devices do not touch the sample. Each method has its advantages and disadvantages, such as the complicated charging method and control method.

On the other hand, the above-mentioned sonic levitation device can be applied to dielectric materials such as glass in addition to metals, if inert gas (He, Ar, etc.) is allowed as the atmospheric gas, so its practical application is desired. . However, the problem with practical application is the stabilization control of the positioning force when combined with a heating furnace.
Create a sound pressure distribution suitable for floating, heat it,
It is necessary to keep it constant as the temperature conditions change during the cooling process.

As a means for stabilizing and controlling the positioning force mentioned above, voice coil type speakers are installed in the three axes of the cubic space (hexahedron), emitting relatively low frequency (1 to 2 KHz) sound, and only the central part is radiated. There is an idea to form a sound pressure mode that causes distortion of the sound pressure distribution, and some preliminary experiments are underway, but such a method has the following problems.

(i) Since it emits a loud sound output of 1 to 2 KHz, it is necessary to take measures to protect the experimenter's hearing.

(ii) In order to use it for space materials experiment equipment, it is necessary to reduce the weight of the magnet part.

(iii) Difficult to combine with heating furnace.

(iv) It is necessary to delicately control the difference in amplitude and phase between the three sound sources.

The present invention involves inserting and fixing a hollow furnace core tube into an elliptical mirror furnace body with a mirror surface formed on the inner surface, and installing a heater for heating the inside of the furnace core tube from outside the furnace core tube. A vibrating body holder is fitted to one end of the vibrating body so as to be movable in the axial direction, and a vibrating body whose vibrating surface faces inside the mirror furnace main body and emits a standing wave that suspends the sample is housed in the vibrating body holder. A reflector is fitted inside the other end of the reactor core tube so as to be slidable in the axial direction of the reactor core tube, and a reflector that faces the mirror furnace center side and reflects the standing wave emitted from the vibrator is fitted to the reflector. A sound pressure detection sensor that forms a surface and detects the sound pressure inside the mirror furnace body is attached, and a rod movable in the core tube axis direction is disposed at the center of the reflector, and the mirror furnace center of the rod is installed. A sample holder is attached to the side protrusion, a sample tube capable of supplying a sample to the sample holder is connected to the reflector side, and a gas supply device for supplying gas into the reactor core tube is provided to the vibrator side. It is characterized by this.

Embodiments of the present invention will be described below with reference to the drawings.

A heating lamp such as a halogen lamp whose axis passes through the vertex on the long axis side and extends parallel to the long axis is installed on both sides in the long axis direction of the mirror furnace body 1, which has an elliptical cross section and a mirror surface formed by gold plating on the inside of the concave surface. The heater 2 is attached, and a hollow quartz furnace core tube 3 whose axis coincides with the short axis is inserted and fixed into the mirror furnace body 1.
The furnace core tube 3 has an inner diameter of about 40 mmφ and a length of about 160 to 200 mm.

One end of the furnace core tube 3 is made to protrude outward to some extent from inside the mirror furnace body 1, and a hollow cylinder 4 is slidably fitted into the protruding inside of the furnace core tube 3.
A reflector 5 and a sound pressure detection sensor 7 whose tip protrudes into the mirror furnace body 1 from the reflective surface 6 of the reflector 5 are attached to the side end of the mirror furnace body 1, and a ball is attached to the outer periphery of the rear end of the cylinder 4. A pulley 9 is attached via a screw 8, and an endless belt 12 is connected between the pulley 9 and a pulley 11 attached to the output shaft of a drive motor 10.
across.

A rod 13 is inserted into the hollow part of the cylinder 4, a morning glory-shaped sample holder 14 is attached to the tip of the rod 13 on the side of the mirror furnace body 1, and a drive motor 1 is attached to the bracket 16 of the frame 15 to which the mirror furnace body 1 is attached.
roller 18 driven by roller 7 and free roller 1
9 are pivotally connected, and the roller 18 and the free roller 19 are
The rod 13 is sandwiched between them, and the rod 13 can be moved forward and backward in the axial direction by frictional force.

A sample tube 20 for introducing a sample is attached to the side of the mirror furnace body 1 on which the sample holder 14 is provided, and the sample tube 20 is communicated with the hole 21 of the furnace core tube 3.

A hollow frame body 22 is attached to the side where the furnace core tube 3 does not protrude to the side of the mirror furnace body 1, and a stepped cylinder whose tip can slide inside the furnace core tube 3 is provided within the frame body 22. A vibrating body holder 23 having a shape is fitted thereinto, a vibrating body 24 is attached to the hollow part of the vibrating body holder 23, and the vibrating body 24 is connected to an oscillator 25.

A screw shaft 26 is attached to the rear end of the vibrating body holder 23, and a pulley 27 has a female thread on the screw shaft 26.
The pulley 27 and drive motor 28 are screwed together.
An endless belt 30 is stretched between the output shaft and a pulley 29 fixed to the output shaft.

As the vibrating body 24, any of electrostrictive type, magnetostrictive type, and electrodynamic type can be used.
In order to position the sample within the
Ultrasonic waves of 20 KHz are suitable, and a bolt-fastened lunge type transducer using PZT (lead zirconate titanate) is used as the piezoelectric element for the transducer. Make the diameter 0.59 to 0.61 times the inner diameter of the furnace tube 3.

A gas supply nozzle 33 connected to a gas component control device 32 is connected to the outside of the frame 22,
The gas supply nozzle 33 is inserted through the hollow part between the frame body 22 and the vibrating body holder 23, the small hole 34 bored in the vibrating body holder 23, and the gap between the hollow part of the vibrating body holder 23 and the vibrating body 24. It communicates with the inside of the furnace core tube 3.

In the figure, 35 is a cooling water pipe spirally attached to the outer periphery of the mirror furnace body 1, 36 is a cooling water pipe of the cylinder 4, 37 is a gas nozzle communicating from the sample tube 20 through the hole 21 into the core tube 3, and 38 is the sample, 41
is a cooling water pipe of the vibrating body 24.

Next, the operation of the present invention will be explained.

The mirror furnace with a sonic levitation device is usually used in outer space, and in this case it can be used in any direction; however, when used on the ground, the vibrating body 24 should be at the top, and the sample holder 14 should be turned upward. It is necessary to work underground, but below we will explain how to work underground.

The floating stable region of the sample in the mirror furnace body 1 is:
Since they generally exist in multiple locations within the furnace core tube 3, it is necessary to confine them in an area with known heating conditions in advance. Therefore, during operation, the drive motor 10 rotates the pulleys 11 and 9 to lower the cylinder 4, and the drive motor 17 rotates the roller 18 to lower the sample holder 14, lowering the sample holder 14 below the sample tube 20. Stop the sample at the position and insert the sample 3 from the sample tube 20.
8 is placed in the sample holder 14, and the drive motor 17 moves the sample holder 14 to a desired central position in the mirror furnace body 1. The sample holder 14 holds the sample 38 and prepositions it in a stable area.

Further, the driving motor 10 moves the cylinder 4 toward the mirror furnace main body 1 to position the reflecting surface 6 at a desired position, and the driving motor 28 moves the vibrating body holder 23 to move the vibrating surface 31 of the vibrating body 24 to the desired position. position, and maintain the vibrating surface 31 and the reflecting surface 6 at a required interval.

Next, the oscillator 25 is activated to mechanically apply vibration to the vibrating body 24. Mechanical vibrations are converted into ultrasonic waves by a bolt-fastened lunge conversion element, which is amplified by a transmitter made of titanium alloy (Ti6Al4V).
Ultrasonic waves are radiated from the vibration surface 31 into the reactor core tube 3 .

The diameter of the vibrating surface 31 is approximately 0.6 times the inner diameter of the reactor core tube 3, and the distance between the vibrating surface 31 and the reflecting surface 6 is adjusted to an appropriate dimension, so that positioning force is generated within the reactor core tube 3 in both the axial and radial directions. The sound pressure distribution, that is, Betssel's [0.1] mode is formed,
The sample 38 is positioned floating from the sample holder 14. Further, after the positioning is completed, the sample 38 is melted by the heater 2.

Although it can be theoretically estimated to some extent that the above sound pressure distribution depends on the frequency of the ultrasonic wave, the speed of sound in the gas, and the inner diameter and length of the reactor core tube 3, in the case of an actual machine,
Since the speed of sound in gas varies depending on the temperature and gas components of the gas, it is difficult to form a constant sound pressure distribution. Therefore, the focus of the mirror furnace of the heater 2 is made linear to stabilize the positioning force so that the heating conditions of the sample 38 do not change even if the floating stable region moves.

Ideally, the sample 38 at room temperature should be suspended and positioned during the entire process of heating, melting, cooling, and solidifying, but the temperature change during that time is
When the temperature reaches 1000℃ or more, the change in sound velocity in the gas more than doubles, and the sound pressure distribution changes significantly. The position of the reflecting surface and the vibration frequency are taken in as data in real time, and these are processed by an arithmetic device (not shown) to output the optimum values of the above factors, and stable floating heating is performed.

Since the mirror furnace with sonic levitation device of the present invention has the above-described configuration, it can achieve various excellent effects as described below.

() Since the heating zone is provided on the axis of the cylindrical sound field and the standing waves are axially symmetrical, the stability of the positioning force during heating is excellent.

() The use of a cylindrical core tube provides good compatibility with the linear focal heater.

() The gas flow supplied to the gas control system flows around the reflector and vibrating transmitter, so it does not disturb the sound field.

() By providing the sample inlet on the reflector side and on the same side as the gas supply port, sample prepositioning can be performed using the gas flow, so it is only necessary to provide the sample holder on the reflector side.

() By simultaneously controlling the gas component ratio and the position of the reflector in the axial direction of the core tube, it is possible to satisfy the ability to follow changes in the wavelength of the sound waves in the core tube due to heating temperature conditions, and to shorten the adjustment stroke of the reflector. , the overall size becomes more compact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention. In the figure, 1 is the mirror furnace body, 2 is the heater, 3 is the furnace tube, 4 is the cylinder, 5 is the reflector, 6 is the reflective surface, 1
4 is a sample holder, 20 is a sample tube, 23 is a vibrating body holder, 24 is a vibrating body, 25 is an oscillator, 2
6 is a screw shaft, 31 is a vibration surface, and 32 is a gas component control device.

Claims (1)

[Claims] 1 A hollow furnace core tube is inserted and fixed into an elliptical mirror furnace body with a mirror surface formed on the inner surface, and a heater for heating the inside of the furnace core tube from the outside is installed, and a heater is installed at one end of the furnace core tube. A vibrating body holder is fitted so as to be movable in the axial direction, and a vibrating body whose vibrating surface faces inside the mirror furnace body and generates a standing wave that suspends the sample is housed in the vibrating body holder. A reflector is fitted inside the other end so as to be slidable in the axial direction of the core tube, and the reflector is fitted with a
A reflecting surface facing the center of the mirror furnace and reflecting the standing waves emitted from the vibrating body is provided, and a sound pressure detection sensor for detecting the sound pressure inside the mirror furnace main body is attached, and the central part of the reflector is A rod movable in the axial direction of the furnace tube is disposed on the rod, a sample holder is attached to the protruding portion of the rod on the mirror furnace center side, and a sample tube is provided on the reflector side so that the sample can be supplied to the sample holder. A mirror furnace with a sonic floating device, characterized in that a gas supply device is connected to the vibrating body and supplies gas into the furnace tube.