JPS6395355A - Probe for measurement in molten metal - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a probe for measuring in molten metal, comprising a measuring element, a housing for the measuring element, and an electrical conductor connected to the measuring element and extending out of the housing.

The probes of this building that have been used to date have been used to
It is particularly suitable for immersion in molten steel for a maximum of several tens of seconds. Therefore, each probe can only provide an instantaneous record of, for example, the temperature or oxygen content of the molten metal.The applicant has manufactured and sold a large number of these maple probes for temperature and oxygen measurements. I've done it. Examples thereof include, for example, French Patent No. 2,382,685 and European Patent Application No. Q of the Applicant;
No. 108,431, respectively.

However, in many situations it is desirable to continuously monitor, for example, the evolution of temperature over a long period of time.For example, in continuous casting equipment, continuous monitoring of the temperature inside the tank that feeds the molten metal to the casting vessel is required. It is especially important to be clear.

To this end, the probe must be suitable to withstand immersion into molten metal during the metallurgical process.

Such processes generally require 1 to 8 hours.

Previously known probes are not suitable for this purpose.Objectives of the Invention It is an object of the present invention to provide probes that can be immersed in molten metal for relatively long periods of time, are therefore suitable for continuous measurements during metallurgical processes, and are relatively inexpensive. SUMMARY OF THE INVENTION It is to provide a probe for measurements in molten metal. It is composed of an outer tube that surrounds the inner 'if' and covers at least the probe portion to be inspected, and a refractory filler disposed between the inner tube and the outer tube.

The refractory filler forms a thermal buffer, suppressing large temperature changes when the probe is immersed in or removed from the molten metal, and also for measuring instruments placed in the molten metal. Large temperature differences between the element part and the measuring element part above the molten metal are eliminated. Such temperature changes or large temperature differences may cause damage to the measuring element.

In one particular embodiment of the invention, the probe further comprises seven tabs surrounding the outer tube.

The tube remains immersed at the same depth throughout the measurement in the molten metal due to the 7-metal float floating on the molten metal, more specifically on the slag formed on the top surface of the molten metal. ing. Thus, temperature fluctuations in the probe due to constant variations in immersion depth during measurements are avoided. Additionally, the float provides additional protection for the remainder of the probe in the generally highly corrosive slag region.

The plate can be formed directly on the outer tube, but is preferably made as a loose fit component and is then removably secured by a catch.

In the latter case, it is not only simple and inexpensive, but also 7
0-) and the rest of the probe can be packaged and transported separately, which means that the space occupied during transport can be used without wasting it, and also reduces the risk of damage during transport.

In a preferred embodiment of the invention, the filler between the inner and outer tubes is a bonded refractory powder. A preferred filler is linoleum bound sand.

In a useful embodiment of the invention, the inner tube is made of ceramic. The inner tube is preferably made of aluminum oxide.

Such aluminum oxide tubes are commercially available and relatively inexpensive. However, aluminum oxide tubing is extremely sensitive to thermal shock. Only by virtue of the above-described construction of the plate according to the invention, even stiff and relatively inexpensive tubes can be used as an envelope for the measuring element.

In a preferred embodiment of the invention, the housing locally surrounds the inner tube inside the outer tube and forms an additional protection for the measuring element and the inner tube in the vicinity of the location where the slug forming on the molten metal is present. It is equipped with an intermediate tube.

In yet another embodiment of the invention, the outer tube is made of metal. The outer tube is preferably made of steel.

In yet another particular embodiment of the invention, the housing comprises:
At the end opposite the immersion end, which lies above the molten metal during measurement, two upper tubes are provided in concentric relation, which correspond to the measuring element and the electrical conductor connected thereto. It surrounds the edge.

In yet another preferred embodiment, the electrical conductor extends out of the housing through a flexible hose. The flexible hose is preferably connected to a source of pressurized air, the source of pressurized air communicating within the housing. The housing is then provided with at least one opening at the immersion end and at the opposite end for allowing the FE-added air to escape. In this specific example,
The top portion of the housing and most of the electrical conductors are cooled by pressurized air.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the present invention, a pool is intended to be partially immersed in a bath of molten metal with a slag formed on the top surface. The probe is immersed in a substantially vertical position, with the end on the lower side in the drawing pointing downward and forming the immersion end. In the following description, the upper and lower ends of the probe or its parts will be defined with reference to the illustrated normal position during hair dipping and therefore measurement.

The sensor essentially comprises a measuring element 1, a housing 2 for the measuring element 1, and two electrical conductors (copper wires) 5 connected to the measuring element 1.

The measuring element 1 is a thermocouple made of -in the example platinum -dium. The thin wire of the measuring element is a small diameter tube 4 made by I, O,
The conductive part inside is advanced and distracted. Thermocouple high temperature combination point 5
is located at the outermost end of the small diameter tube 4. The cold side junction is inside a small steel tube 6 attached to the upper end of the small diameter tube 4. The copper tube forms a connection with the cold side junction, where the wires of the thermocouple are electrically connected to two electrical conductors, namely copper wires 3. 7 and an outer tube 8, preferably made of steel. The inner tube 7 has a closed bottom and houses a small diameter tube 4 containing a measuring element (thermocouple) 1 therein.

The gap between the inner tube 7 and the outer tube 8 is filled with a refractory material, i.e. 81 (h
, filled with a filler material 9 made of W fat-impregnated sand such as chromite sand or zirconium sand.

After the resin-impregnated sand has been filled into the tubes 7 and 8 thresholds, e.g.
A heat treatment is performed at a temperature of 50° C. for 10 minutes. This causes the sand to condense into solid bodies.

The gap between the inner tube 7 and the small diameter tube 4 is filled with a refractory filler 1a such as MKO powder, for example.

The filler 9 forms a thermal buffer around the measuring element 1, while the filler 10 improves the stability and thermal balance of the measuring element.

Inside the outer tube 8, the inner tube 7 is surrounded over part of its length by an intermediate tube 11. The intermediate tube 11 is embedded in the filling material 9. The intermediate tube 11 is also preferably made of AlzOs.
The additional protection tube for the measuring element 1 is ensured in particular by the molten metal at about the same level as the slag on the molten metal.

In order to keep the response time of the measuring element, in particular the thermocouple, as short as possible, the lower end of the measuring element is not surrounded by an intermediate tube 11.

The outer tube 8 may have the same diameter throughout its entire length.

However, it is preferred that the outer tube 8 has a reduced diameter, as shown, at its lower end where the intermediate v1j is absent. This is to minimize the response time of the measuring element, in particular the thermocouple. The outer tube 8 can be constructed of two separate parts with different diameters, as shown. In this case, the lower outer tube portion of the small diameter has its upper end connected to the filler material 9 which is present between the upper portion of the outer tube 8 and the inner tube 7.
embedded inside.

Another feature of the present invention is that the outer tube 8 is made of refractory cement.
This is covered by Section 12.13. 7vx
-) consists of a disc-shaped part 12 and a circular extension part 15 connected thereto on the lower side.

will be accomplished.

70-Flat 12, j3 allows the entire probe unit to levitate above the molten metal, thereby allowing the float) 12.13
is located on the top surface of the molten metal and therefore at the same level as the slag. The disc-shaped part 12 ensures sufficient stability, and at the same time the extension part 13 serves as an additional protection for the probe remainder at the slug location. The small diameter extension 13 allows for material savings and a weight reduction of 70 tons.

70-) 12.13 may be fastened directly to the outer tube, for example around a plate welded thereto. However, 7a-t1
2.13 Preferably, it is made separately from the rest of the probe as shown. Not only is this easier to make, but it can be packaged and shipped separately from the tablet, eliminating wasted space during shipping and reducing the risk of damage to the tablet. The floats 12, 13 are fastened to the outer tube 8 immediately before use of the probe. On the upper surface of the disk-shaped portion 12, an L-shaped 7-piece 14 with one leg protruding from the upper surface is machined, and this protruding leg is fixed to the inside of the outer tube 8 with a small screw 15. In particular, the inner tube 7 and the outer tube F8 extend from the inside to the same height when the tube is suspended in the molten metal FA, but are narrow diameter tubes containing the measuring element 1. It does not extend beyond trf4.

The upper part of the small diameter tube 4 and thus the upper part of the measuring element 1, including the small copper tube 6, is surrounded by two overlapping upper IWs 16.17 made of aluminum. Upper tube 17
The lower end of the outer tube 8 is fitted into the open upper end of the outer tube 8 and the intermediate tube 11
It has grown to the upper level of . The outer upper tube 17 is fastened to the outer tube 8 by a small screw 18, and the gap between the upper end of the outer q7!8 and the outer upper tube 17 is sealed by a seal 19.

The inner upper tube 16fi projects upward from the outer upper tube 17 and extends to the upper end of the intermediate tube 11 at its lower end.

The space between the upper pipes 16 and 17 is filled in the lower part with a filling material 20 made of refractory powder, while the space between the upper pipes 16 and 17 is
and 17 are held in an open state by a spacer 21 at the upper part. However, the ring-shaped opening between the upper end of the outer upper g17 and the inner upper tube 16 is not completely closed (for the purpose described later).

The uppermost end of the inner upper tube 16 is sealed with a sea/&/22.

A flexible hose 23 passes through the seal 22iJj, and two conductors 5 are interposed therethrough.

The flexible hose 25 is a synthetic tube surrounded by a small LA-knitted glass fiber tube. The flexible hose 25 is connected to the T-piece 2 at a distance from the housing 2.
It is connected to the first arm of 4. The second arm of the T-piece 24 is connected to a pressurized air pump 26 via a tube 25'. The conductor 3 extending within the flexible hose 25 extends further through the third arm of the T-piece 24, which is sealed around the conductor at its outer end.

Air is pumped through the flexible tube 25 and around the conductor 3 by the pump 26 . The pressurized air enters through the I# end of the tube 23 in the inner upper g16 and cools the small [tube 6t] which houses the measuring element, in particular the upper part of the thermocouple 1 and the cold side junction.

Pressurized air flows from the inner upper tube 16 through holes 27 formed in its wall.
It flows out completely, enters the annular space above the filler 20 between the upper tubes 16, 17, and flows out through the opening between the spacers 21.

The present invention is not limited to the specific examples described above, but many changes may be made in shape, composition, arrangement, number of parts, etc., without departing from the spirit of the invention. In particular, the ceramic for the small diameter tube, inner tube and outer tube containing the measuring element does not necessarily have to be aluminum oxide.

Other ceramics such as ZrO2 can also be used. The outer tube does not necessarily have to be made of steel. The outer tube may be made from other metals or materials. The outer tube does not have to consist of two separate parts, as already mentioned. In the above specific example, 7. ) forms a separate part from the rest of the probe 0 The probe end itself is 7! - It is also possible to use it by yourself without having to use it. The measuring element is not limited to a thermocouple for temperature measurement, and may also be an element for measuring activity such as oxygen activity, for example. The oxygen activity measuring element is
A single laminate may be formed with the inner tube and, for example, the inner tube may be isolated at the immersed end.

Effects of the Invention The present probe has an extremely simple structure and is relatively inexpensive. The probe allows the use of inexpensive materials such as aluminum oxide for many tubes without the risk of tearing due to thermal shock.

The 70-t ensures accurate and stable positioning of the probe and provides additional protection for the remainder of the probe near the same level as the slug. The disc-shaped portion also forms a kind of heat shield that limits upward heat radiation. The upper tubes 16 and 17 reflect most of the thermal radiation that is still present, thereby maximally protecting the thermocouple etc. and the upper part of the conductor 5.

Such thermal protection is further improved by cooling using pressurized air.

This probe can be used to perform measurements over long periods of time. This probe is operationally reliable and relatively inexpensive.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view of a probe for measuring in molten metal according to the invention. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. 1: Measuring element 2: Housing 3: Electrical conductor 6: Copper tube 7: Inner tube 88 Outer tube 9: Filler 11: Intermediate tube 12.13: Float 16.17: Upper tube 25: Flexible hose 26: Pressurized air source 24: 1-shaped part 27: hole 21 varnish base, 11. −、−Paishi・? :; Mouth.

Claims (1)

Claims: 1) In molten metal comprising a measuring element (1), a housing for the measuring element (2) and an electrical conductor (3) connected to the measuring element and extending outside the housing. In the measuring probe, the measuring element housing (2
) is an inner tube made of refractory material (7) having a measuring element therein.
, an outer pipe (8) surrounding the inner pipe so as to cover at least a portion to be immersed in molten metal, and a filler made of a refractory material (9) disposed between the inner pipe and the outer pipe. A probe comprising: 2) The probe according to claim 1, comprising a float (12, 13) surrounding the outer tube (8). 3) The float (12, 13) is made as a separate part from the rest of the probe and the fastener (14,
15) The probe according to claim 2, which is fixed by the probe. 4) The floats (12, 15) are connected to the disk-shaped portion (12
) and an extension (13) at the immersed end of the probe for additional protection of the remainder of the probe against slag formed above in the molten metal. Probe as described. 5) The probe according to any one of claims 1 to 4, wherein the filler (9) between the inner tube (7) and the outer tube (8) is a bonded refractory powder. 6) A probe according to claim 5, wherein the filler (9) is resin-bonded sand. 7) Probe according to claim 6, wherein the filler (9) is a resin-bonded sand selected from silicium oxide, chromite and zirconium sand. 8) Probe according to any one of claims 1 to 7, in which the inner tube (7) is closed at the immersion end. 9) The probe according to any one of claims 1 to 3, wherein the inner tube (7) is made of ceramic. 10) The probe according to claim 9, wherein the inner tube (7) is made of aluminum oxide. 11) The housing (2) locally surrounds the inner tube (7) inside the outer tube (8) and closes the measuring element (1) and the inner tube (7) in the vicinity of the level of the slag that forms on the molten metal.
Probe according to any one of claims 1 to 10, comprising an intermediate tube (14) forming an additional protection for the probe. 12) The probe according to claim 1, wherein the intermediate tube (14) is made of ceramic. 13) The probe according to claim 12, wherein the intermediate tube (11) is made of aluminum oxide. 14) Claims in which the outer tube (8) consists of two parts of different diameters, namely a first part around the middle tube (11) and a part of smaller diameter surrounding the submerged end of the inner tube (7). 12th to 1st
The probe according to any one of item 3. 15) Claim in which the outer tube (8) consists of two separate parts with different diameters, which are joined together by a filler (9) between the inner tube (7) and the outer tube (8). The probe according to item 14. 16) Claims 1 to 1, wherein the outer tube (8) is made of metal.
16. The probe according to any one of item 15. 17) Claim 16, wherein the outer tube (18) is made of steel.
Probes described in section. 18) The probe according to any one of claims 1 to 17, wherein the measuring element is housed in a small diameter ceramic tube (4). 19) Claims in which the measuring element is a thermocouple, the hot side junction of which is located outside the narrow diameter tube (4) at the immersed end and the cold side junction is located outside the other end of the narrow diameter tube (4) Probe according to item 18. 20) A connection body in which the measuring element has a small copper tube (6) with a cold-side junction inside, and the copper tube (6) electrically connects the thermocouple (1) itself to the conductor (3). 20. A probe according to claim 19 forming a probe. 21) The small diameter tube (4) containing the measuring element (1) and the inner tube (7)
21. The probe according to any one of claims 18 to 20, wherein the void between the probe and the probe is filled with a refractory material at least on the immersion end side. 22) The probe according to claim 21, wherein the refractory material is MgO. 23) The housing (2) comprises at its end opposite the immersion end, which is positioned above the molten metal during the measurement, two overlapping metallic upper tubes (16, 17), which upper tubes carry the measuring element ( 1) and the electrical conductor (3) connected thereto
23. A probe according to any one of claims 1 to 22, surrounding the corresponding end of the probe. 24) The probe according to claim 23, wherein the upper tubes (16, 17) are made of aluminum. 25) Probe according to claim 23 or 24, in which an outer upper tube (17) projects at one end into the end of the outer tube (8) and is fixed thereto. 26) The inner upper tube (16) connects at one end to the intermediate tube (
26. The probe according to any one of claims 25 to 25, which is connected to the end opposite to the immersion end of 14). 27) Probe according to any one of claims 25 to 26, wherein the space between the two upper tubes (16, 17) is filled with refractory material at least on the side facing the immersion end. 28) The electrical conductor (5) extends outwardly of the housing (2) through the flexible hose (23).
28. The probe according to any one of items 27 to 27. 29) A flexible hose (23) connected to a source of pressurized air (26) and opening into the housing (2) and escaping pressurized air at an end opposite the immersed end into the housing (2); 29. A probe as claimed in claim 28, comprising at least one aperture for the purpose of disposing the probe. 30) A flexible hose (23) opens into the interior space of the inner upper tube (16), and the inner upper tube (16) supplies pressurized air to its wall between the inner upper tube (16) and the outer upper tube ( 17), at least one hole (27) for allowing the flow to flow into the gap between the
The outer upper pipe (17) opens at the end opposite to the immersion end to allow pressurized air to escape.
The probe according to any one of Items 7 and 29. 31) A flexible hose is connected in its first arm to the T-shaped part (24), the second arm is connected by a tube (25) to a source of pressurized air and the electrical conductor (3) is connected to the third
31. A probe as claimed in claim 29 or 30, extending out from the T-piece through the arm of the T-piece and through its seal. 32) Claim 28, wherein the flexible hose is made of synthetic material surrounded by small woven glass fiber tubes.
32. The probe according to any one of items .