EP3189315A2

EP3189315A2 - Measuring device for optically determining the temperature of a molten metal, and plug

Info

Publication number: EP3189315A2
Application number: EP15762482.6A
Authority: EP
Inventors: Harald Fischer; Gerhard Wünsch; Torsten Lamp; Herbert KÖCHNER
Original assignee: Minkon GmbH; BFI VDEH Institut fuer Angewandte Forschung GmbH
Current assignee: Minkon GmbH
Priority date: 2014-09-01
Filing date: 2015-08-21
Publication date: 2017-07-12
Also published as: WO2016034271A2; DE102014012698B4; WO2016034271A3; DE102014012698B8; DE102014012698A1

Abstract

The invention relates to a measuring device for optically determining the temperature of a molten metal, comprising: - an optical waveguide to conduct electromagnetic radiation emitted by the metal or by the tip of the optical waveguide to an optical detector, - an optical detector for determining the temperature of the metal from an analysis of the electromagnetic radiation, - a reeling device for successively reeling off the optical waveguide from a stock and a duct, which is connected to the reeling device so that a fluid can pass through and through which fluid flows, and in which the optical waveguide is at least conducted in sections and in which the optical waveguide is transported by means of the fluid, the duct through which fluid flows and the reeling device forming a gas-tight system relative to their surroundings. The invention further relates to a plug for an outlet opening of a container which accommodates the molten metal. Said plug has a refractory rod-shaped body with an upper and a lower end, and a channel that axially extends through at least part of the rod-shaped body and leads to a surface of the lower end. In order to optically determine the temperature of molten metal an optical waveguide is conducted through the channel.

Description

"Measuring device for the optical temperature determination of a molten metal and sealing plug"

The invention relates to a measuring device for the optical temperature determination of a molten metal and a sealing plug.

Such a measuring device is known, for example, from WO 2007/079894 A1. Here, an optical fiber is supplied to a container of a converter which receives molten metal. The optical waveguide has the task of guiding the electromagnetic radiation of the molten metal to an optical detector. Between the optical detector and the container, a fluid-flow line is arranged, in which the optical waveguide is guided and in which the optical waveguide is transported by means of the fluid. In a preferred embodiment, the invention has an unwinding device which unwinds the optical waveguide successively from a supply. This is necessary because the high temperatures at the measuring point mean that the optical waveguide melts gradually at its end immersed in the molten metal and must be adjusted accordingly.

In a preferred embodiment of the invention according to WO 2007/079894 A1, a process gas line can be used as a transport line for the optical waveguide. The process gas line can be, for example, a line system for the supply of treatment gas. The treatment gas is supplied to the molten metal via a bottom opening of the converter. In such

CONFIRMATION COPY Fluid lines often have such a high pressure that a special sealing of the measuring device for the optical temperature determination of the molten metal is necessary. But even with transport lines with lower pressure seals of the measuring device must sometimes be made to ensure the transport of the optical waveguide and to avoid damage to parts of the measuring device. An insufficient seal can also falsify the measurement result.

It is therefore known to arrange the measuring device in a gastight housing. In the housing then, for example, unwinding device, optical detector, signal evaluation, control, cooling system, rotary coupler, fiber consumption meter and other components are housed. To seal such a system is very expensive. Additionally, such a seal may be costly due to the need to use gas-tight and pressure-resistant electronic components.

The invention further relates to a closure plug for an outflow opening of a container receiving molten metal. Such a sealing plug is known for example from DE 41 42 773 A1.

In order to determine the temperature of a molten metal that flows out of the container via the outflow opening, there is proposed to attach a thermocouple in a channel extending axially in the rod-shaped plug. By way of example, the use of the sealing plug in a distributor of a continuous casting apparatus is shown. It is noticeable that the stopper according to

Although DE 41 42 773 A1 is able to measure the temperature of the metal melt flowing out of the distributor. Its measuring range ends in the distributor (and does not even extend to the lower end of the sealing plug). A temperature measurement in a dip tube or even in a mold is impossible here. In addition, the device according to DE 41 42 773 A1 has the disadvantage that the

Sensor is not in direct contact with the molten metal, whereby the measuring sensitivity is limited.

Against this background, the object of the invention is to propose an improved seal for a measuring device for the optical temperature determination of a molten metal, in which an optical waveguide is transported via a line through which fluid flows. Against this background, the invention is further based on the object of proposing a closure plug for closing an outflow opening, in particular at the bottom of a container, which receives molten metal, with which it is possible to determine the temperature of the molten metal, in particular by means of a according to the invention to reach points below the plug, with the probe in direct contact with the molten metal.

This object is solved by the subject matter of claim 1. Advantageous embodiments are specified in the subclaims.

The invention is based on the basic concept of restricting the gas-tight design of the measuring device to that part of the measuring device which is necessary for the transport of the optical waveguide.

The measuring device according to the invention has a fluid-flow line in which an optical waveguide is guided at least in sections and in which the optical waveguide is transported in a preferred embodiment with the aid of a fluid.

The optical waveguide has the task of conducting electromagnetic radiation emitted by the metal or by the tip of the optical waveguide to an optical detector. Due to the high temperatures at the measuring point, the optical waveguide melts gradually and must be adjusted accordingly.

Therefore, the measuring device according to the invention further comprises an unwinding device for successively unwinding the optical waveguide from a supply. The unwinding device according to the invention expediently has a receiving location for the stock. The receiving location may be, for example, a rod-shaped device. This is particularly well suited for a supply in the form of a drum winch, around which the optical fiber is wound, and which has an axial central bore, through which the stock can be conveniently inserted into the rod-shaped device. Alternatively, the supply may be a looped fiber optic cable, ball or the like. The unwinding device is preferably located in its own gas-tight and pressure-resistant housing.

Expediently, the fluid-flow-through line and the unwinding device are fluid-permeable to one another. As a result, it is possible for the optical waveguide to be transported by the unwinding device to the measuring point via the fluid-flow line by means of the transport fluid. According to the invention, the line through which the fluid flows and the unwinding device form a system which is gastight with respect to its surroundings. Most preferably, the gas-tight system is pressure resistant, ie, all components in the system withstand high pressures without impairing function and damage. In this way, eliminating the need to form the entire system gas-tight and pressure resistant. As an overall system, not only the entire measuring device according to the invention is to be understood. Additional devices in the metal fabrication process and metal casting processes may also be included. It has been shown that the measurement accuracy could be increased by the measuring device according to the invention. In addition, it is possible to save enormous costs for the sealing of the entire system. Elaborate maintenance is also eliminated.

In a preferred embodiment, the optical detector, which is arranged outside the gas-tight system, is connected to the optical waveguide via a gas-tight optical feedthrough.

The optical detector serves to determine the temperature of the metal from an analysis of the electromagnetic radiation which is fed to it via the optical waveguide. The optical detector is therefore connected to the optical waveguide, which is located in the gas-tight system. So that the transmission of the electromagnetic radiation is not subject to any optical degeneration, it is expedient to connect the optical detector to the optical waveguide via the gas-tight optical feedthrough.

In a preferred embodiment, the optical detector is arranged in a gas-tight system. It makes sense that this is gas-tight and pressure-resistant. As a rule, an optical detector converts optical signals into electrical signals. In a particularly preferred embodiment, the optical detector forwards the electrical signals to a signal evaluation, which is located outside the gas-tight system on. The detector and the signal evaluation are connected via a gas-tight electrical feedthrough.

The line through which fluid flows can be a transport line which is provided separately for the supply of the optical waveguide and which, for example, is above a free transport line

Surface of the molten metal can end and brings the optical waveguide there in contact or in the vicinity of the molten metal to absorb the electromagnetic radiation emitted by the metal. In a preferred embodiment, the fluid-flow line is connected to a gas line, with the treatment gas is introduced into the molten metal. In this case, the optical waveguide is guided at least in sections in the gas line and transported through the treatment gas. Although this is very advantageous that an existing gas line can be used as a transport line and thereby eliminates conversion measures. All- Recently, such gas lines can sometimes have high pressures. With the measuring device according to the invention, it is now possible to use such gas lines as transport lines without making special and costly Abdichtmaßnahmen the entire system.

Preferably, the fluid-flow line is connected via an insertion opening in the gas line to the gas line. In this case, the insertion opening is arranged in the region of a gas source. In a preferred embodiment, the fluid-flow line and the

Gas line connected via a shut-off valve. This makes it possible to close the shut-off valve when no temperature measurement is required. At the same time, however, gas may flow through the gas line to treat the molten metal without transporting the optical fiber. In this advantageous manner, the optical waveguide is not unnecessarily consumed. In addition, in the non-measured periods, the gas-tight system according to the invention can be relieved of the process pressure by closing the shut-off valve. The shut-off valve can be designed so that the optical waveguide is guided even when the shut-off valve is closed, for example, by squeezing a seal.

Advantageously, the shut-off valve is actuated automatically. In this case, for example, the shut-off valve can automatically open or close at a certain pressure value. The automatic actuation can be effected, for example, hydraulically, electrically or mechanically. Particularly preferably, the shut-off valve can be used as an actuator in a control or a control circuit.

The object is solved by the subject matter of claim 8. Advantageous embodiments are specified in the subclaims.

The essence of the invention is to provide a sealing plug, through which an optical waveguide for optical temperature determination can be performed.

Conveniently, the closure plug in a preferred embodiment, a rod-shaped body of refractory material to temperatures up to

1600 ° C and beyond. The term "rod-shaped" is to be interpreted broadly, for example, it should not be limited to a cylindrical geometry, but rather it should be understood that the length of the body is (very) much larger than its diameter or its width. The body has an upper and a lower end, the lower end being intended to be directed to the outflow opening. According to the invention, "end" does not only mean a surface, for example an end surface, but may also be a section, so that it has, for example, lateral surfaces or a lateral surface.

In a metal-making or metal casting process, such as in continuous casting, the plug is usually vertically aligned and located above the outlet port. By vertical movement of the sealing plug, the outlet opening can be closed and opened, wherein the closure, the lower end is connected to the outlet opening.

In order to pass the optical waveguide through the sealing plug, the sealing plug has a channel extending axially through at least part of the rod-shaped body. The channel opens at a surface of the lower end. In particular, it is preferably the lower end side of the body, so that the optical waveguide can be continued beyond the lower end even with an outlet opening closed by the sealing plug, for B. to a measuring point as in a dip tube or a mold.

Preferably, the channel is connected to the surface of the upper end to introduce the optical waveguide in the channel. This is preferably the end face of the upper end. However, it is also possible to connect the channel with a lateral surface of the upper end in order to introduce the optical waveguide laterally into the sealing plug.

Channel sections are conceivable which do not extend axially, in particular which extend laterally. The channel or the channel sections can in principle be connected to any surface of the sealing plug. The channel may also have branches, e.g. B. with the same or different cross-sectional areas and cross-sectional shapes, for example, to obtain sections of different flow velocities and pressures. The cross-sectional profile over the channel length or channel section length can also vary as desired. In addition, every conceivable channel system is possible.

Conveniently, the channel (s) is drilled or created by casting. The casting process is particularly suitable for complicated duct systems. The channel preferably has a circular cross-section.

In a particularly advantageous embodiment, the sealing plug on a measuring device according to one of claims 1 to 7. If necessary, it is included the closure plug gas-tightly connected to the fluid-flow line, z. B. via an adapter or flange.

A measuring device for the optical temperature determination, in which an optical waveguide is transported as Meßgrößenaufnehmer in a fluid-flow line by means of a fluid could not be used in all metal production and metal casting due to the fluid flow. The fluid flow may be too strong or undesirable at certain locations. For example, too much fluid flow in a mold during continuous casting can cause the metal mold, which is just beginning to solidify, to be damaged. Therefore, it is provided in a particularly preferred embodiment that the channel is formed such that it has an upper and a lower end and that in a channel flowing from the upper to the lower end fluid, in particular for transporting the optical waveguide, an overpressure at the top End and a negative pressure at the bottom arises. This makes it possible that the optical waveguide is well transported due to a strong flow at the upper end, while at the same time at the lower end of a weaker flow, which may not adversely affect the manufacturing or casting process prevails. Preferably, this is realized by the channel towards the lower end

Has cross-sectional widening, which extends over at least part of the channel and is continuous or discontinuous, approximately stepped, executed, and that depending on the flow velocity of the fluid targeted a turbulent flow in the region of the cross-sectional widening can be achieved.

In the turbulent flow, the boundary layer of the fluid (fluid layer in the wall area) separates from the channel wall, whereupon turbulences form, which slow the flow. The conditions for the transition from a laminar to a turbulent flow can be determined by means of the Reynolds number. Influences which can be controlled in a practical manner are, in particular, the flow velocity and the channel cross section. Another factor influencing the targeted production of turbulence in the flow-through channel may also be the fluid viscosity. Alternatively or additionally, a resistance body may be arranged such that it is flowed around by the fluid at a fixed location in the channel and that the resistance body is designed such that a turbulent flow arises downstream of the resistance body, which generates or amplifies the negative pressure at the lower end. Upstream of the resistor body, the fluid builds up and creates an overpressure. On the downstream side, however, creates a vortex zone with

Vacuum. The resistance body can, for example, have a simple spherical shape. have and be connected to a thread-like tension element, by means of which the resistance body is axially positionable in the channel. If necessary, the resistance body can be displaced, in which way the location and the intensity of the turbulence can be controlled.

The sealing plug according to the invention is particularly advantageously suitable for carrying out an optical temperature determination of molten metal in a dip tube and / or a mold in a continuous casting plant. Particularly preferably, the temperature is determined by means of the measuring device according to the invention. The optical waveguide is guided through the channel and through the outlet opening in the distributor to an otherwise hardly reachable measuring point in the dip tube or even in the mold. The optical waveguide is arranged as a sensor in direct contact with the molten metal and not, as in the prior art, inside a solid body and surrounded by this / sheathed. The measuring device has in this way a particularly increased measuring sensitivity. In addition, a continuous temperature measurement is possible by the successive tracking of the optical waveguide. As a result, the continuous casting process can be optimized and the quality of the continuous casting products significantly increased.

The invention will be explained in more detail with reference to drawings, which show only exemplary embodiments of the invention. Show:

Fig. 1 is a schematically sectional side view of the invention

Measuring device and

Fig. 2 is a schematically sectional side view of a closure plug according to the invention with a distributor and a mold.

1 shows an embodiment of the measuring device 1 according to the invention, which is used for the optical temperature determination of a molten metal 2, which is located in a converter 3. The gas-tight system 4 here consists of an unwinding device 5, which comprises a receptacle for a light-wave supply, and a fluid-flow line 6 for transporting an optical waveguide 7 to the molten metal 2 via a bottom opening in the converter 3.

The transport line consists of two sections. The first section forms the fluid-flow-through line 6, the second a gas line 8. The gas line 8 serves to melt the molten metal 2 with a treatment gas, eg. As oxygen supply. The gas is fed via a gas supply 9 with a gas source, not shown, in the gas line 8. The fluid-flow line 6 and the gas line 8 are connected to each other via a shut-off valve 10, so that z. B. the treatment process can also take place without an optical fiber feed when the shut-off valve 10 is closed. The gas-tight system 4 is housed in the embodiment in an enclosure 11, in which other components of the measuring device, such as an optical detector 12 and a signal evaluation 13, are located. Since the unwinding device 5 and the fluid-flow line 6 are already formed gas-tight, it is not necessary to form the housing 1 1 gas-tight. Likewise, the components in the enclosure may be ordinary components that need not be gas-tight and pressure-resistant. Figure 2 shows a schematic representation of an embodiment of the sealing plug according to the invention.

It can be seen a longitudinal section of the sealing plug 14, which closes an outflow opening of a distributor 15 of a continuous casting plant. Also visible is a dip tube 16 and a mold 17 of the continuous casting plant. An optical waveguide 7 as a measuring sensor of a measuring device 1 according to the invention (not shown) is guided through a channel 18 of the sealing plug 14. The channel 18 has at the bottom of a cross-sectional widening 19 for conditioning a turbulent flow at the lower end 20 of the channel, so that the flow emerging from the channel 18 is decelerated. The optical waveguide 7 can, as shown in Figure 2, to the mold

17 (and beyond) continue and record the electromagnetic radiation of the molten metal in the dip tube 16 or in the mold 17 for the optical temperature determination. Preferably, this is done continuously by the optical waveguide 7 is tracked successively.

Claims

claims:

Measuring device (1) for the optical temperature determination of a molten metal (2) with

an optical waveguide (7) for guiding electromagnetic radiation emitted by the metal (2) or the tip of the optical waveguide (7) to an optical detector (12),

an optical detector (12) for determining the temperature of the metal (2) from an analysis of the electromagnetic radiation,

- An unwinding device (5) for successively unwinding the optical waveguide (7) from a supply,

a fluid-flow conduit (6) connected fluid-permeable to the unwinding device (5), in which the optical waveguide (7) is guided at least in sections,

characterized in that the fluid-flow line (6) and the unwinding device (5) with respect to their environment form a gas-tight system (4).

Measuring device (1) according to claim 1, characterized in that the optical detector (12) outside the gas-tight system (4) is arranged and connected via a gas-tight optical passage with the optical waveguide (7).

Measuring device (1) according to claim 1, characterized in that the detector (12) in the gas-tight system (4) is arranged.

Measuring device (1) according to one of claims 1 to 3, characterized in that the fluid-flow line (6) with a gas line (8), with the treatment gas is introduced into the molten metal (2), and in that the optical waveguide (7 ) is guided in the gas line (8) at least in sections and transported through the treatment gas.

Measuring device (1) according to claim 4, characterized in that the fluid-flow line (6) via an insertion opening in the gas line (8) is connected to the gas line (8), wherein the insertion opening is arranged in the region of a gas source.

6. Measuring device (1) according to claim 4 or 5, characterized in that the fluid-flow line (6) and the gas line (8) via a shut-off valve (12) are connected.

7. Measuring device (1) according to claim 6, characterized in that the shut-off valve (12) is actuated automatically.

8. Closure plug (14) for an outflow opening of a container receiving molten metal (2) comprising a rod-shaped body of refractory material

an upper and a lower end (20),

a channel (6) which extends axially through at least part of the rod-shaped body and opens at a surface of the lower end (20), characterized in that, for the optical temperature determination of molten metal (2), an optical waveguide (7) passes through the channel (6). 20) is guided.

9. sealing plug (14) according to claim 8 with a measuring device (1) according to one of claims 1 to 7.

A closure plug (14) according to claim 8 or 9, characterized in that the channel (20) is formed to have upper and lower ends (20) and in that the channel (20) from the upper one to the second one bottom end (20) flowing fluid, in particular for the transport of the

Fiber optic cable (7), an overpressure at the upper end and a negative pressure at the lower end (20) is formed.

A closure plug (14) according to any one of claims 8 to 10, characterized in that the channel (20) is formed to have upper and lower ends (20) and at one the channel (20) from the upper one to the lower end (20) flowing fluid, in particular for transporting the optical waveguide (7), a low negative pressure at the upper end and a stronger negative pressure at the lower end (20) is formed.

12. Closure stopper (14) according to claim 10 or 11, characterized in that the channel (20) towards the lower end (20) towards a cross-sectional widening (19) which extends over at least part of the channel (20) and continuously or discontinuously, approximately stepwise, is executed, and that depending on the flow velocity of the fluid targeted a turbulent flow in the region of the cross-sectional widening (19) can be achieved.

13, sealing plug (14) according to claim 10 to 12, characterized in that a resistance body is arranged such that it is flowed around at a fixed location in the channel (20) of the fluid and that the resistance body is formed such that downstream of the resistance body creates a turbulent flow, which generates or amplifies the negative pressure at the lower end (20).

14. Use of the sealing plug (14) according to claims 8 to 13 for the optical temperature determination of molten metal (2), preferably by means of the measuring device (1) according to claims 1 to 7, in a dip tube (16) and / or a mold (17) in a continuous casting plant.