JP2010071666A - Airtight melting facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airtight melting facility capable of accurately measuring the temperature of molten metal continuously by using an optical fiber. <P>SOLUTION: The airtight melting facility 1 includes an airtight tank 2 for housing a melting furnace 3 and holding the furnace in an airtight atmosphere, an optical fiber 4 in a metal tube whose one end 4a is dipped in the molten metal 3a inside the melting furnace 3, a temperature detecting section 6 connected to the other end of the optical fiber 4, a guide section 7 for inserting the optical fiber 4 and guiding the fiber from the outside of the airtight tank 2 into its inside, an optical fiber feed section 6 for continuously feeding the optical fiber 4 through the guide section 7 into the molten metal 3a, and a hermetic seal section 72 for hermetically sealing the insertion portion of the optical fiber 4 in the guide section 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an airtight melting facility that enables continuous measurement of the temperature of a molten metal using an optical fiber.

  Various thermometers for measuring the temperature of the molten metal in the melting furnace for melting metals and melting equipment equipped with such thermometers are conventionally known. Among these, in an open-type melting facility that melts metal at atmospheric pressure, the end of a long optical fiber is sequentially fed into the melt, and the radiated light incident from the end of the optical fiber is sent to the temperature at the other end. A configuration in which the temperature of the molten metal is continuously detected by detection by a detection unit is considered (see, for example, Patent Document 1).

On the other hand, in a vacuum melting facility that places the melting furnace in a vacuum state, an auxiliary chamber connected by a valve is provided above the vacuum chamber that houses the melting furnace. An insertion rod for guiding the temperature element and an evacuation device for replacing the temperature measuring element are provided. A temperature measuring element applied to such a vacuum chamber is generally called a consumable lance thermocouple, and has a configuration in which a quartz glass portion in which the tip of the thermocouple is housed is held by a protective tube. ing. And whenever this quartz glass part is immersed in the molten metal and the temperature of the molten metal is measured, the valve between the vacuum chamber and the auxiliary chamber is closed, the vacuum evacuation device is opened, the temperature measuring element is taken out, and a new temperature measuring element is obtained. The next temperature measurement is carried out by exchanging with.
JP 2005-227277 A

  However, since the melting furnace to which the temperature measuring device capable of continuously measuring the molten metal using the optical fiber described above is applied is an open type, it is easy to supply or replace the molten optical fiber. In a vacuum-type or air-tight type melting facility that can obtain a molten metal of quality, strict temperature control is required. Therefore, the above-described temperature measuring device using an optical fiber cannot be applied as it is. On the other hand, in the vacuum melting equipment using the temperature measuring element as described above, the quartz glass portion is damaged immediately when immersed in the molten metal, and therefore only one temperature measurement can be performed, and the response speed is slow. It takes several seconds to show the maximum temperature. Furthermore, the replacement of the temperature measuring element is an operation that requires time and labor to raise the insertion rod to the auxiliary chamber and then open the vacuum exhaust device, during which the temperature of the molten metal decreases. The temperature and quality of the molten metal is difficult to control, and reheating is necessary. In general, when a metal is melted under vacuum, the metal evaporates, so that it is difficult to see the inside of the vacuum chamber from the outside, and even the brightly shining molten metal may be difficult to see. For this reason, a method of suppressing the evaporation of metal by introducing an inert gas into the vacuum chamber is conceivable, but it is difficult to completely suppress the evaporation, and it is difficult to see even if a lighting fixture is installed in the vacuum chamber. It is not possible to completely eliminate this problem. Therefore, in the conventional method described above, there is a possibility that the temperature measuring element is excessively immersed in the molten metal, or even the tip of the insertion rod is immersed in the molten metal.

  In view of such a problem, the main object of the present invention is to provide an air-tight melting facility capable of accurately measuring the temperature of a molten metal continuously using an optical fiber.

  In other words, the hermetic melting equipment according to the present invention includes a metal tube in which a melting furnace is housed and held in an airtight atmosphere, and an optical fiber immersed at one end in the molten metal in the melting furnace is covered with a metal tube. A coated optical fiber, a temperature detection unit connected to the other end of the metal tube-coated optical fiber outside the hermetic tank, a guide unit that guides the metal tube-coated optical fiber from the outside to the inside, and the guide An optical fiber supply unit that continuously supplies the metal tube-coated optical fiber into the molten metal through the unit and an airtight seal unit that seals the insertion portion of the metal tube-coated optical fiber in the guide unit are provided.

  With the hermetic melting equipment having such a structure, it is possible to measure the temperature quickly and accurately by continuously inserting and immersing the metal tube coated optical fiber using the optical fiber into the molten metal of the melting furnace in the hermetic tank. Moreover, the sealed state of the hermetic tank can be maintained by the hermetic seal portion. That is, according to the present invention, it is no longer necessary to open and close the auxiliary chamber and replace the temperature measuring element by operating the valve of the hermetic tank every time measurement is performed. It is possible to significantly reduce the time and labor required for the process. In addition, even if the inside of the airtight tank is not visible due to the molten metal vapor, it is sufficient to keep the guide part in a position where it is not immersed in the molten metal so that only the metal tube-coated optical fiber is immersed in the molten metal. It is possible to eliminate the possibility of problems such as excessive immersion of the temperature measuring element and immersion of the insertion rod as in the prior art. In the present invention, the “airtight atmosphere” refers to a state where the airtight tank is maintained in a sealed state, and the inside of the airtight tank is in a vacuum state in which the pressure is lower than the atmospheric pressure in that state, or It is preferable to be in a state filled with an inert gas such as argon.

  In the present invention, the guide portion is provided with a guide portion moving means for moving the guide portion between a use position where one end of the metal tube-coated optical fiber is immersed in the molten metal in the melting furnace and a retracted position pulled up from the molten metal. By doing so, the tip of the metal tube-coated optical fiber is inserted into the melt only when measuring the temperature of the melt while keeping the length of the metal tube-coated optical fiber extending from the tip of the guide portion constant. When the temperature measurement is not performed, the metal tube-coated optical fiber with the guide portion is retracted from the melting furnace, so that it does not interfere with the operation of putting the metal into and out of the melting furnace.

  In particular, the guide part moving means provided in the guide part can be provided with a speed adjusting mechanism capable of changing the moving speed of the guide part between the use position and the retracted position. If comprised in this way, a guide part will be moved at high speed when the distance between a molten metal and a metal tube coating optical fiber is long, and if the distance between a molten metal and a metal tube coated optical fiber will become near, a guide part will be moved at low speed. By doing so, it is possible to effectively avoid a situation in which the guide portion is immersed in the molten metal while reducing time loss.

  Further, when the guide portion operates, particularly when the guide portion is operated with respect to the airtight tank, it is necessary to maintain an airtight state between the guide portion and the airtight tank. For this purpose, it is appropriate to further provide a second hermetic seal portion for sealing the attachment site between the guide portion and the hermetic tank.

  In addition, as a guide portion, a simple structure that occupies a small space and is easy to operate can include a tubular member in which a metal tube-coated optical fiber is inserted into an airtight tank. .

  According to the present invention, the configuration in which the tip of the metal tube-coated optical fiber can be continuously immersed in the molten metal in the melting furnace is applied to the hermetic melting equipment, and the metal tube-coated optical fiber is applied to the hermetic tank by the guide unit. At the time of introduction, the sliding portion between the metal tube-coated optical fiber and the guide portion is configured to be kept in an airtight state by the seal portion. In addition to eliminating the difficulty of time and temperature control of the molten metal, it is possible to measure the molten metal temperature continuously and accurately, improving operational stability and reliability, and improving product quality. .

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overview diagram showing a part of the airtight melting facility 1 according to the present embodiment with a part thereof omitted. The hermetic melting equipment 1 includes a hermetic tank 2, a melting furnace 3 disposed in the hermetic tank 2, a metal tube-coated optical fiber 4 used for measuring the temperature of the molten metal 3a in the melting furnace 3, a metal An optical fiber supply unit 5 that feeds the tube-coated optical fiber 4, a temperature detection unit 5 that detects the temperature of the molten metal 3 a through the metal tube-coated optical fiber 4, and a guide unit 7 that guides the metal tube-coated optical fiber 4 into the melting furnace 3. And the guide part moving means 8 which moves the guide part 7 with respect to the airtight tank 2 is provided as a main structure.

  The airtight tank 2 is an airtight container capable of maintaining the inside in a vacuum, and is designed to withstand the high temperature of the molten metal 3a. In FIG. 1, only the upper end part side of this airtight tank 2 is shown, and the lower end part side and other parts are omitted. At the upper end of the hermetic tank 2, a conduit 21 that accommodates a guide part 4 to be described later and guides it into the hermetic tank 2 is provided so as to protrude obliquely upward. The conduit 21 is made of, for example, a stainless steel tube or the like, and as shown in FIGS. 2 and 3, the conduit 21 is inclined by support columns 23 and 24 provided on a pedestal 22 provided at the upper end of the airtight tank 2. The posture is supported.

  In the present embodiment, the melting furnace 3 installed in the hermetic tank 2 is an induction furnace in which a melting crucible 31 is heated by an induction coil 32 wound around its body.

  The metal tube-coated optical fiber 4 has a configuration in which the optical fiber 41 is protected by a flexible metal tube 42 as shown in part in cross-sectional views in FIGS. 4 and 5. As long as the metal tube 42 is made of a material that does not affect the molten metal 3a even if the molten metal 3a is melted together with the optical fiber, an appropriate material can be adopted. If the molten metal is titanium, the metal tube 42 can be made of titanium.

  The optical fiber supply unit 5 includes a drum 51 that winds and holds the metal tube-coated optical fiber 4 and a sending unit 52 that continuously feeds the metal tube-coated optical fiber 4 drawn from the drum 51. As the drum 51, a drum 51 in which a metal tube-covered optical fiber 4 of, for example, about 50 to 100 m can be wound is adopted. Moreover, the sending part 52 can be comprised, for example from the pinch roller 52a rotated on both sides of the metal pipe coating | coated optical fiber 4, and the motor 52b which rotationally drives this pinch roller 52a.

  A radiation thermometer connected to one end of the metal tube-covered optical fiber 4 on the side wound around the drum 51 is applied to the temperature detection unit 6. For example, InGaAs can be used as the detection element. The radiation thermometer detects radiation emitted from the tip of the optical fiber 41 and transmitted through the optical fiber 41 in the metal tube-coated optical fiber 4 immersed in the molten metal 3a, and continuous temperature detection is possible. It has become.

  In this embodiment, the guide portion 7 is mainly composed of an insertion rod 71 made of a metal pipe that can withstand the high temperature in the airtight tank 2. The inner diameter of the insertion rod 71 is slightly larger than the outer diameter of the metal tube-coated optical fiber 4, and the insertion rod 71 is inserted through the inside 71 of the insertion rod 71 so that the metal tube-coated optical fiber 4 can freely slide. The tip portion 4 a of the metal tube-coated optical fiber 4 is projected from the tip portion 71 a of 71. An airtight seal portion 72 that seals between the inner wall of the insertion rod 71 and the outer wall of the metal tube-coated optical fiber 4 is provided at the sliding portion of the upper end portion of the insertion rod 71 with the metal tube-coated optical fiber 4. ing. In this embodiment, a Wilson seal is applied as the hermetic seal portion 72. That is, the hermetic seal portion 72 is provided with a plurality of upper and lower elastomer sheets 72b inside the Wilson seal main body portion 72a provided at the upper end portion of the insertion rod 71, as schematically shown in FIG. At the same time, vacuum grease is filled between the upper and lower elastomer sheets 72b, and the metal tube-coated optical fiber 4 is inserted into the central portion thereof, whereby the airtightness between the guide portion 7 and the metal tube-coated optical fiber 4 is achieved. Holding.

  The guide part moving means 8 has a use position (FIG. 2) in which the insertion rod 71 through which the metal tube-coated optical fiber 4 is inserted is immersed in the molten metal 3a in the melting furnace 3 with the tip 4a of the metal tube-coated optical fiber 4. The tip 4a of the metal tube-coated optical fiber 4 is slid relative to the airtight tank 2 (more specifically, the conduit 21) between the retracted position (FIG. 3) where the tip 4a is pulled up from the melting furnace 3. Specifically, as shown in detail in FIGS. 2 and 3, the guide portion moving means 8 is routed over a predetermined range in the longitudinal direction of the motor 81 and the conduit 21, and a part thereof is connected to the upper end portion 71 b of the insertion rod 71. The roller chain 82 is attached and rotated by a motor 81. A cable bear 83 is also provided between the insertion rod 71 and the conduit 21 to prevent the motor 81 and the compensating conductors from becoming messy or tangled. Suppression of blurring during the operation of the insertion rod 71 can also be expected.

  Thus, since the insertion rod 71 operates with respect to the airtight tank 2 by the guide portion moving means 8, the second airtight seal is provided at an appropriate portion of the conduit 21, which is the attachment portion of the insertion rod 71 to the airtight tank 2. By providing the portion 25, the airtightness at this portion is maintained. In the second hermetic seal portion 25, as shown in FIG. 5, a pair of lid bodies 25a and 25b that divide the mid-height position of the conduit 21 and spatially separate the upper portion thereof, and an O-ring 25c sandwiched between them. A cylinder 25d erected on the upper lid 25a and fitted on the insertion rod 71; a cap 25e fitted on the upper end of the cylinder 25d and fitted on the insertion rod 71; The upper and lower O-rings 25f and 25g are attached in close contact between the inner wall of 25d and the outer wall of the insertion rod 71.

  The motor 81 in the guide portion moving means 8 can change the rotation speed as appropriate, and functions as a part of the speed adjustment mechanism of the present invention. For example, when the insertion rod 71 and the metal tube-coated optical fiber 4 are moved from the retracted position to the use position, as shown in FIGS. 2 and 3, the tip 4 a of the metal tube-coated optical fiber 4 is placed in the melting furnace 31. When it is within a predetermined range (area A in the figure) from the retracted position that is the position farthest from the molten metal 3a, the insertion rod 71 is operated at a high speed, and the distal end portion 4a of the metal tube-coated optical fiber 4 extends from the area A to the molten metal. When it is within a predetermined range (region B in the figure) slightly approaching 3a, the insertion rod 71 is decelerated and operated at a low speed, and the tip 4a of the metal tube-coated optical fiber 4 further approaches the molten metal 3a from this region B. When it is within the predetermined range (region C in the figure), the insertion rod 71 is further decelerated and operated at an extremely low speed, and the insertion rod 71 is stopped when the tip of the insertion rod 71 is immersed in the molten metal 31. The rotation speed of the motor 81 is adjusted. It has to be. The boundary between the region A and the region B is set in advance, and the rotation of the motor 81 is switched from high speed to low speed by position detection means (not shown) such as a limit switch. In addition, when the temperature detection unit 6 detects a predetermined temperature when the tip of the metal tube-coated optical fiber 4 comes into contact with or near the surface of the molten metal 3a, the rotation of the motor 81 is changed from a low speed to a very low speed. When the switching is performed and the temperature detection unit 6 detects that the tip of the metal tube-coated optical fiber 4 is immersed in the molten metal 3a, the rotation of the motor 81 is stopped. When the motor 81 stops, the motor 51b of the optical fiber supply unit 5 is operated to feed the metal tube-coated optical fiber 4 from the drum 51a, thereby feeding the metal tube-coated optical fiber 4 from the tip 71a of the insertion rod 71. Thus, the temperature of the molten metal 3a is continuously measured. Thus, by controlling the speed when the insertion rod 71 is moved from the retracted position to the use position, the reliability and safety of the temperature measurement operation is improved, and the insertion rod 71 is accidentally immersed in the molten metal 3a. It is possible to effectively prevent the metal tube-coated optical fiber 4 from being wasted. Here, since the length of the metal tube-coated optical fiber 4 consumed by one temperature measurement is about 10 mm, the metal tube-coated optical fiber 4 is successively sent out from the optical fiber supply unit 5 so that the length is 5000 continuously. Temperature measurement more than once is possible. When the insertion rod 71 and the metal tube-coated optical fiber 4 are moved from the use position to the retracted position, the motor 81 is rotated at a high speed to quickly lift the metal tube-coated optical fiber 4 from the molten metal 3a. What is necessary is just to prevent consumption of the coated optical fiber 4.

  Thus, according to the hermetic melting equipment 1 of the present embodiment, not only can the temperature of the molten metal 3a in the hermetic tank 2 in a vacuum atmosphere be continuously measured, but also the metal tube-coated optical fiber 4 immersed in the molten metal 3a. Can be used without waste, and the stability and ease of temperature measurement can be improved. Moreover, since the insertion site | part to the guide part 7 of the metal pipe covering optical fiber 4 and the operation | movement site | part with respect to the airtight tank 2 of the guide part 7 are maintained in an airtight state, without reducing the temperature of the molten metal 3a. Since it is possible to continuously measure the temperature of the molten metal 3a under vacuum, the temperature management of the molten metal 3a becomes easy, and the quality of the molten metal 3a can be improved.

  In addition, this invention is not limited to embodiment mentioned above. For example, the inside of the airtight tank may be not only in a vacuum state, but also in a state where the internal atmospheric pressure is slightly lower than the atmospheric pressure or filled with an inert gas such as argon gas. Further, the specific configuration of each part in the airtight melting equipment such as the guide part, the airtight seal part, and the second airtight seal part is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. Is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The figure which shows the principal part of the state which has located the guide part in the same airtight melt | dissolution installation in a use position. The figure which shows the principal part of the state which has located the guide part in the same airtight melt | dissolution equipment in the retracted position. The typical sectional view showing the outline of the airtight seal part in the airtight dissolution equipment. The typical sectional view showing the outline of the 2nd airtight seal part in the airtight dissolution equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Airtight melting equipment 2 ... Airtight tank 3 ... Melting furnace 3a ... Molten metal 4 ... Metal pipe coating optical fiber 5 ... Optical fiber supply part 6 ... Temperature detection part 7 ... Guide part 8 ... Guide part moving means 25 ... 2nd airtight seal Part 41 ... Optical fiber 42 ... Metal tube 71 ... Insertion rod (tubular member)
72 ... Hermetic seal part 81 ... Motor (speed adjustment mechanism)

Claims (5)

A hermetic tank containing a melting furnace therein and maintained in a hermetic atmosphere; a metal tube-coated optical fiber having one end coated with a metal pipe and an optical fiber immersed in the molten metal in the melting furnace; and the outside of the hermetic tank A temperature detection unit connected to the other end of the metal tube-coated optical fiber, a guide unit for inserting the metal tube-coated optical fiber from the outside to the inside of the hermetic tank, and the metal tube through the guide unit An optical fiber supply unit that continuously supplies a coated optical fiber into the molten metal, and an airtight seal unit that seals an insertion site of the metal tube coated optical fiber in the guide unit. Facility. The guide part moving means is further provided for moving the guide part between a use position where one end of the metal tube-coated optical fiber is immersed in the molten metal in the melting furnace and a retracted position pulled up from the molten metal. The airtight dissolution facility according to 1. The hermetic melting equipment according to claim 2, wherein the guide part moving means is provided with a speed adjusting mechanism capable of changing a moving speed of the guide part between the use position and the retracted position. The airtight dissolution facility according to any one of claims 2 and 3, further comprising a second airtight seal portion that seals an attachment site of the guide portion in the airtight tank. The hermetic melting equipment according to any one of claims 2 to 4, wherein the guide portion is a tubular member into which the metal tube-coated optical fiber is inserted and inserted into the hermetic tank.

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