GB1565215A - Two-part ceramic probe for sampling a steel converter - Google Patents

Description

(54) A TWO-PART CERAMIC PROBE FOR SAMPLING A STEEL CONVERTER (71) We, MANNESMANN AKTIEN GESELLSCHAFT, a German Body Corporate of 2 Mannesmannufer, 4 Düsseldorf 1, Federal Republic of Germany and GUSTAV KOLB, a German citizen of 5984 Garbeck, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a two-part ceramic probe adapted to be fitted to a cardboard tube for withdrawing a sample from a blowing steel converter.

One such mould is known from German Patent Specification No. 2,126,501 in the form of and used as a device for establishing the carbon content of the steel melt. The solidified extracted sample thereby obtained and which, determined by its function of recording the liquidus line, shows a thickness which is sufficiently large to guarantee a comparatively slow solidification, is only apparently a sample in the sense of a laboratory sample for carrying out a quick spectral and gas analysis. As is known, suitable laboratory samples have the shape of a disc with the size of 32 mm diameter and 12 mm thickness, with an entry pin or plug belonging to the sample and with a thickness of 6 mm.

As a known device of a different type for taking the indicated laboratory sample from a blowing converter, there could possibly be considered a device in which a sheet metal dished mould is held inside the end piece of a carboard tube of suitably large dimensions, and in which the supply is through a small quartz tube emerging at the front from the cardboard tube. The quartz tube is protected with a sheet metal cap which melts away in the steel bath, the cap containing aluminium which causes deoxidation. A thermocouple is also provided, which extends at the front from the cardboard tube. With such a device, the deoxidation products pass into the probe together with particles of slag which in the turbulent steel melt are able to pass unhindered into the sample probe.Such disadvantages are not shown by the known, ceramic device of the type initially referred to and having a downwardly directed entry chamber.

The aim of the invention is to provide a ceramic probe which is suitable as a casting mould for a laboratory sample. As regards the utility value of the device in practice, the ceramic probe is so designed that it can be easily smashed, with rapid delivery of the laboratory sample, while utilizing the lowest possible consumption of noble metal.

According to the invention there is provided a two-part ceramic probe for attachment to a tubular cardboard lance for extracting a sample from a blowing steel converter, the probe comprising a pair of complementary mould cavity halves forming a mould cavity corresponding to disc-shaped and pin-shaped laboratory samples, and an entry duct which together with the pin-shaped cavity forms a U-shaped channel, the mould cavity halves being connected to each other along a joint, extending longitudinally of the ceramic probe, and a thermocouple being positioned in a recess above the mould cavity when the probe is inserted in the steel converter.

As is hereinafter shown, the ceramic probe according to the invention also satisfies cost conditions as regards the practical value of the probe in use. The temperature-measuring position is in fact sufficiently far away from the cardboard tube so as not to be impeded by the reaction gases forming violently on the cardboard tube, but not as far as is the case with the known ceramic probe.

As a consequence, the necessary length of expensive platinum wire is comparatively small.

In a preferred construction of the ceramic probe, one of the two parts is a substantially mirror-image of the other. This has the advantage of simple manufacture and uniform thermal stressing of the mould.

The thermocouple which may be a prefabricated ceramic component, can be arranged on the opposite side of the probe to the entry for the steel sample. So as not to endanger the temperature-sensitive tip of the thermocouple and also the conventional sheet metal protective cap at the time of inserting the probe, it is advisable to so shape the probe body that an offset is provided, in which those parts of the thermocouple sensitive to impact can be arranged. Another possibility as regards the arrangement and the best mechanical protection of the thermocouple is for the thermocouple to be arranged in a suitable enlarged inlet opening of the entry for the steel sample.

The ceramic probe according to the invention is based on a device for carbon evaluation, a further development of the invention provides for the ceramic probe to be so constructed that it is additionally possible to evaluate carbon. For this purpose, between the thermocouple and the sample cavity, there is arranged a further sample cavity, the thickness of which differs insignificantly from the width. A second thermocouple extends into the further sample cavity, and it is expedient for the second thermocouple also to be arranged in a suitable probe recess, i.e. in a branch thereof. Both sample cavities can be supplied from the same entry passage. In order to ensure that it is the first sample cavity which is first filled with steel, it is desirable to connect the second sample cavity with an obliquely ascending branch passage to the entry passage.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a side view of one half of a probe body for extracting samples from a blowing converter and a longitudinal section through the supporting carboard tube, Figure 2 shows the probe consisting of two mirror-image halves according to Figure 1 as an elevation in the direction of the arrow II, Figure 3 shows the device according to Figure 1 as a section through both halves of the probe body taken along line Ill-Ill in Figure 1, Figure 4 is a side view of one half of a probe body for extracting a laboratory sample from a blowing converter and simultaneously for extracting a sample for carbon evaluation and a longitudinal section through the supporting carbon tube, and Figure 5 shows the probe consisting of two mirror-image halves according to Figure 4 as a section through both halves of the probe body taken along the line V-V in Figure 4.

The probe body comprises two mirrorimage halves 1 and 2, fired from a ceramic material and having a joint 3 extending in the immersion direction longitudinally of the probe. The probe contains cavities 4 and 5 for the laboratory sample as already previously designated and having the dimensions as also already indicated. The laboratory sample includes a disc portion and a pin portion and consequently the probe body contains a disc-shaped cavity 4 and a pin-shaped cavity 5. The cavity 5 extends longitudinally of the probe and serves in known manner as a steel entry passage to the cavity 4. Consequently, the pin is hereinafter referred to as the entry pin.

A U-shaped channel is formed by the cavity 5, an entry passage 6 which extends longitudinally of the probe alongside the cavities 4 and 5, and a connection 7 between the cavity 5 and the entry passage 6, the cross-section of connection 7 being larger than the cavity 5. The entry opening 8 is closed by a sheet metal disc 9, which is secured in a groove. A coil of aluminium wire 10, in the form of a helix, is disposed in the entry passage 6.

The probe body halves 1 and 2 are fitted on to a thick-walled cardboard tube 11 which serves as a lance. The probe has a neck portion 12 which is inserted into the one end of the cardboard tube 11, as shown in the drawing. As a modification of this construction, the cardboard tube 11 can also be inserted into a neck portion of the ceramic probe, the portion being made in the form of a socket (not shown). It is also possible for the ceramic probe to be provided with a socket portion in addition to having the neck portion 12, so that the bonding can be carried out on the inside and outside surfaces of the cardboard tube 11.

The cardboard tube does not serve for holding the two halves 1 and 2 together, these two halves are in fact firmly and tightly jointed together by ceramic firing or by sticking with ceramic slip before the insertion of the neck portion.

A recess 13, which is open at the top, extends at an angle to a temperaturemeasurement point 14 of a thermocouple, which is covered by a sheet-metal cap 15.

When the device is in the position for use, the recess 13 accommodates thermocouple wires and their soldering point, in a suitably shaped special ceramic component. Only the temperature-measuring point 14 is indicated as a soldering point for this component which is not shown. The temperature-measurement point is ',ituated at the height of and on the opposite side to the lateral entry opening 8 and is protected by an offset 16, the shape of which is determined by the shape of the cavity 4. as indicated in the drawing.

When the device probe is immersed in a blowing converter, the sheet-metal disc 9 and the sheet-metal cap 15 quickly melt away, and simultaneously with the entry of the steel into the passage 6, the temperature of the steel is measured by the thermocouple.

On account of the comparatively large cross-sections of the passages 6 and 7, as shown in the drawing, the coil of aluminium wire 10 which is immediately oxidised with the entry of the unkilled steel is not carried along into the mould cavities 5 and 4, but remains as slag in the passage 6.

Consequently, this guarantees that the sample extracted by the probe is representative of the state of the steel in the converter at that time.

The modified ceramic probe shown in Figures 4 and 5, which also serves for establishing the carbon content of the melt simultaneously with the extraction of the laboratory sample from the steel bath and simultaneously with the measurement of the steel bath temperature, is provided with the same reference numerals to corresponding parts of the embodiments of the ceramic probe illustrated as described in Figures 1 to 3. The differences are as follows: Arranged between the thermocouple 14 and the cavity 4 is a cavity 17, which has the form of a hollow sphere. It is important that the thickness of the sample taken is exactly equal to the width or only differs insignificantly therefrom. In this respect, the shape of this sample can, for example, be that of a cube or that of a rhomboid.

Correspondingly, the ceramic probe has a distinct bulge at this portion, as shown in Figure 5. In a manner similar to Figure 2, the probe body shown in Figure 5 also comprises two mirror-image halves 18, 19, which are fired together at the longitudinally extending joint 3. A second thermocouple 20 extends into the cavity 17, as far as the centre thereof. A suitable ceramic support for this thermocouple is embedded in a branch 21 of the recess 13.

The ceramic component which is positioned and firmly cemented therein, for the purpose of producing the condition for use, and which contains the two thermocouples, seals the cavity 17 in the upward direction.

Of course, and this also applies as regards the cavity 4, small-calibre air-venting ducts are formed in the probe and, in fact, in the joint 3, but these are not shown. The cavity 17 is connected bv an obliquely ascending branch duct 22 to an entry passage 23, which in this example is longer than the passage 6 of the first embodiment. In this arrangement the duct 22 and the passage 23 to the entry opening 8 make an acute angle ensuring that the steel only runs into the cavity 17 when the cavity 4 is filled, at least for the major part, with steel.

A modification of the arrangement of the thermocouple in such a way that this element extends into the upper end of the entry passage 6 or 23 is not illustrated. By suitable shaping of the point of curvature of the entry passage it is ensured that there is no constriction in cross-section. Such a method of construction has the advantage that the cap 15 is dispensed with and the sensitive tip of the ceramic component, which has the soldering position for the thermocouple lies protected in the best possible manner inside the ceramic probe.

WHAT WE CLAIM IS: 1. A two-part ceramic probe for attachment to a tubular cardboard lance for extracting a sample from a blowing steel converter, the probe comprising a pair of complementary mould cavity halves forming a mould cavity corresponding to disc-shaped and a pin-shaped laboratory samples and an entry duct which together with the pin-shaped cavity forms a U-shaped channel, the mould cavity halves being connected to each other along a joint, extending longitudinally of the ceramic probe and a thermocouple being positioned in a recess above the mould cavity when the probe is inserted in the steel converter.

2. A probe according to claim 1, wherein one of the two parts is substantially a mirror-image of the other.

3. A probe according to claim 1 or 2, wherein the thermocouple is arranged on that side of the mould which is opposite an entry opening to the entry duct.

4. A probe according to claim 3 wherein a temperature measurement point of the thermocouple is protected by an offset portion of the probe body.

5. A probe according to claim 1 or 2, wherein the thermocouple is arranged in a suitable enlarged inlet opening for the sample.

6. A probe according to any one of the preceding claims wherein between the thermocouple and the cavities, there is arranged a further cavity, the thickness of which differs insignificantly from the breadth, and into which extends a second thermocouple which is provided in a branch of the recess.

7. A probe according to claim 6, wherein

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. temperature-measurement point is ',ituated at the height of and on the opposite side to the lateral entry opening 8 and is protected by an offset 16, the shape of which is determined by the shape of the cavity 4. as indicated in the drawing. When the device probe is immersed in a blowing converter, the sheet-metal disc 9 and the sheet-metal cap 15 quickly melt away, and simultaneously with the entry of the steel into the passage 6, the temperature of the steel is measured by the thermocouple. On account of the comparatively large cross-sections of the passages 6 and 7, as shown in the drawing, the coil of aluminium wire 10 which is immediately oxidised with the entry of the unkilled steel is not carried along into the mould cavities 5 and 4, but remains as slag in the passage 6. Consequently, this guarantees that the sample extracted by the probe is representative of the state of the steel in the converter at that time. The modified ceramic probe shown in Figures 4 and 5, which also serves for establishing the carbon content of the melt simultaneously with the extraction of the laboratory sample from the steel bath and simultaneously with the measurement of the steel bath temperature, is provided with the same reference numerals to corresponding parts of the embodiments of the ceramic probe illustrated as described in Figures 1 to 3. The differences are as follows: Arranged between the thermocouple 14 and the cavity 4 is a cavity 17, which has the form of a hollow sphere. It is important that the thickness of the sample taken is exactly equal to the width or only differs insignificantly therefrom. In this respect, the shape of this sample can, for example, be that of a cube or that of a rhomboid. Correspondingly, the ceramic probe has a distinct bulge at this portion, as shown in Figure 5. In a manner similar to Figure 2, the probe body shown in Figure 5 also comprises two mirror-image halves 18, 19, which are fired together at the longitudinally extending joint 3. A second thermocouple 20 extends into the cavity 17, as far as the centre thereof. A suitable ceramic support for this thermocouple is embedded in a branch 21 of the recess 13. The ceramic component which is positioned and firmly cemented therein, for the purpose of producing the condition for use, and which contains the two thermocouples, seals the cavity 17 in the upward direction. Of course, and this also applies as regards the cavity 4, small-calibre air-venting ducts are formed in the probe and, in fact, in the joint 3, but these are not shown. The cavity 17 is connected bv an obliquely ascending branch duct 22 to an entry passage 23, which in this example is longer than the passage 6 of the first embodiment. In this arrangement the duct 22 and the passage 23 to the entry opening 8 make an acute angle ensuring that the steel only runs into the cavity 17 when the cavity 4 is filled, at least for the major part, with steel. A modification of the arrangement of the thermocouple in such a way that this element extends into the upper end of the entry passage 6 or 23 is not illustrated. By suitable shaping of the point of curvature of the entry passage it is ensured that there is no constriction in cross-section. Such a method of construction has the advantage that the cap 15 is dispensed with and the sensitive tip of the ceramic component, which has the soldering position for the thermocouple lies protected in the best possible manner inside the ceramic probe. WHAT WE CLAIM IS:

1. A two-part ceramic probe for attachment to a tubular cardboard lance for extracting a sample from a blowing steel converter, the probe comprising a pair of complementary mould cavity halves forming a mould cavity corresponding to disc-shaped and a pin-shaped laboratory samples and an entry duct which together with the pin-shaped cavity forms a U-shaped channel, the mould cavity halves being connected to each other along a joint, extending longitudinally of the ceramic probe and a thermocouple being positioned in a recess above the mould cavity when the probe is inserted in the steel converter.

2. A probe according to claim 1, wherein one of the two parts is substantially a mirror-image of the other.

3. A probe according to claim 1 or 2, wherein the thermocouple is arranged on that side of the mould which is opposite an entry opening to the entry duct.

4. A probe according to claim 3 wherein a temperature measurement point of the thermocouple is protected by an offset portion of the probe body.

5. A probe according to claim 1 or 2, wherein the thermocouple is arranged in a suitable enlarged inlet opening for the sample.

6. A probe according to any one of the preceding claims wherein between the thermocouple and the cavities, there is arranged a further cavity, the thickness of which differs insignificantly from the breadth, and into which extends a second thermocouple which is provided in a branch of the recess.

7. A probe according to claim 6, wherein

the further cavity is connected with an obliquely ascending branch duct to the entry passage.

X. A two-part ceramic probe substantially as herein described with reference to and as shown in the accompanying drawings.