Immersion probe and assembly of immersion sublance and immersion probe for a converter furnace

An immersion probe with a variable connection length is configured to compensate for longitudinal and/or radial length variations in an immersion sublance connected to the immersion probe. The immersion probe is characterized by an adjustable portion that changes length upon engagement with a coupling end of an immersion sublance. The immersion probe can have a sensor head. An immersion assembly of the immersion probe connected to an immersion sublance can be used to take measurements or samples of molten metal in a converter furnace.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application, filed under 35 U.S.C. § 371, of International Application No. PCT/EP2015/081232, which was filed on Dec. 24, 2015, and which claims priority to Brazil Patent Application No. BR 10 2014 033086 0, which was filed on Dec. 30, 2014, the contents of each of which are incorporated by reference into this specification.

FIELD OF THE INVENTION

The present invention relates to an immersion probe and an assembly of an immersion sublance and an immersion probe to perform measurements and/or take samples out of a converter furnace filled with molten metal. The immersion probe is configured to feature a variable length.

BACKGROUND OF THE INVENTION

Immersion sublances and immersion probes are broadly used in converter furnaces during steelmaking processes. Typically, pig iron and scrap metal are discharged into the converter furnace, which fuses them together at a high temperature (e.g., 1600 to 1750° C.), thus producing steel.

In order to produce a high quality product having ideal chemical characteristics, the molten metal has to be subjected to several chemical analyses. The aim is to monitor all the chemical elements contained in the steel, for example, by controlling, among others, the carbon, carbon equivalents and silicon concentration, or by monitoring the hardness, resistance, machinabily, temperature, and/or oxidation level.

Such chemical analyses are performed by means of sensing or sampling the molten metal, those operations being performed by sensors located at the end of an immersion probe.

Conventionally, during the production of molten metal, a blowing lance is used to blow oxygen inside the converter furnace at supersonic speed onto molten slag and molten metal.

In parallel, the assembly of an immersion sublance and an immersion probe is inserted from the external environment into the inside of the converter furnace following a longitudinal direction, such that only the immersion probe of said assembly is submerged into molten slag and subsequently into molten metal. Once in contact with molten metal, the immersion probe is able to perform measurements and/or take samples of molten metal by means of sensors or sampling chambers. Upon fulfillment of those tasks, the assembly of the immersion sublance and the immersion probe is taken out of the converter furnace, and the immersion probe is then disconnected from the immersion sublance and then discarded.

The connection of the immersion probe to the immersion sublance is performed before the insertion of the assembly into the converter furnace, said connection being partially automated.

As previously mentioned, the immersion probe is used only once during the immersion and/or measurement process. On the other hand, the immersion sublance can be reused, for it is provided with a longer service life.

Considering that the immersion sublance is used for several immersions and/or measurements, deformations due to harsh ambient conditions and high temperatures inside the converter furnace have been observed after several immersions and/or measurements by the sublance. Such deficiencies are quite common and severe, resulting in difficulty connecting a new immersion probe to the immersion sublance.

More specifically, a deformed immersion sublance can present connection problems with a new immersion probe, resulting in clearance problems between the sublance holder and the immersion probe. Such characteristics are not desirable, and can lead to various problems.

Since the immersion probe structure is typically made of cardboard and does not possess precise dimensions, it has been observed that the immersion probe cannot completely cover the immersion sublance holder. Furthermore, depending on the climatic conditions, as well as the storage location of the immersion probes, it is known that deformations can occur on the cardboard constituting the probes' casings, creating radial or longitudinal variations. Considering this problem, it is known that when the assembly of an immersion sublance and an immersion probe is inserted into the converter furnace, some molten metal splashes might land on the sublance holder, making the connection to a new immersion probe difficult.

In order to avoid this problem, an attempt has been made in the art to counter the deformation of the immersion sublance. The European Patent EP-A1-69433 describes a sublance presenting a fixed upper end and a lower end which can rotate. It specifically discloses that the lower portion of the immersion sublance gets deformed after the first immersion in molten metal, then the sublance is taken out of the converter furnace and its lower end is rotated 180°. After said rotation, the sublance is then immersed anew. According to the teachings of European Patent EP-A1-69433, this feature allows the lower portion to come back to its original position (before the first immersion).

Another known solution is described by the U.S. Pat. No. 4,566,343. This patent discloses an immersion sensor comprising a rubber seal designed to prevent molten metal from penetrating into the immersion sublance.

In addition, another solution aimed at improving the connection between the immersion probe and the sublance holder is also known in the art. US-B2-7370544 describes the use of a spring or an elastic ring on the sublance holder. This solution is problematic, considering that the immersion sublances currently commercialized require some adjustments in order to accommodate the spring or the elastic ring. In this way, it becomes mandatory to stop the measurement process in order to adapt the sublance described in US-B2-7370544.

Considering the above solutions, it is observed that in the state of the art, the use of an immersion probe with a variable connection length, able to compensate for length variations in the longitudinal and/or radial directions of the immersion sublances, is not known.

Furthermore, the current state of the art provides no solution for the use of an immersion probe with a variable connection length without requiring the adaptation of the immersion sublances, such that immersion sublances currently commercialized could be used without requiring any adaptation.

BRIEF SUMMARY OF THE INVENTION

The first aim of the present invention is to provide an immersion probe enabling a greater connection efficiency with an immersion sublance holder.

The second aim of the present invention is to provide an immersion probe that can be connected to immersion sublances currently commercialized without any need to adapt them.

Another aim of the present invention is to provide an immersion probe that can be connected to immersion sublances with a variable connection length.

Yet another aim of the present invention is to provide an immersion probe that can be connected to immersion sublances that have been deformed by consecutive immersions into a converter furnace.

In addition, the present invention also aims at providing an immersion probe that can prevent molten metal from sticking onto an immersion sublance holder.

Providing an immersion probe that prevents connection defects or clearance problems with an immersion sublance is also among the aims of this invention.

Finally, the present invention aims at compensating for the longitudinal and/or radial length variations of an immersion sublance upon connection.

The aims of the present invention are achieved by an immersion assembly for a converter furnace comprising an immersion sublance and an immersion probe. The immersion sublance comprises a guide connecting end, the guide connecting end configured to couple to a first coupling end of a sublance holder. The sublance holder extends longitudinally from the first coupling end to a second coupling end, wherein the sublance holder connects to the immersion probe through a connection between the second coupling end of the sublance holder and an adjustable portion of the immersion probe.

The aims of the present invention are also achieved by an immersion probe for a converter furnace comprising a casing and an adjustable portion. The casing features an internal cavity in order to receive the adjustable portion, wherein the adjustable portion extends longitudinally along the internal cavity of the casing, from a connecting portion to a fixed portion. The connecting portion and the fixed portion are attached to one another through an elastic portion, wherein the elastic portion is configured to change the length of the adjustable portion once a first contact point has been established with the surface of the connecting portion.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates an inside view of a converter furnace100used in the steel industry for producing and refining steel. During the production of molten metal, a blowing lance30is used inside the converter furnace100, said blowing lance30being used for injecting oxygen at supersonic speed on molten slag40and molten metal50.

Still referring toFIG. 1, an assembly formed by an immersion sublance1connected to an immersion probe2is shown. The assembly formed by said components is inserted into the inside of a converter furnace100. The assembly of the immersion sublance1and the immersion probe2is configured to extend longitudinally from the external environment into the direction of the inside of the converter furnace100. More specifically, the assembly extends such that the immersion probe2is immersed into the molten metal50lying underneath the molten slag40. When immersed, the immersion probe2performs measurements and/or takes samples of molten metal50. Afterwards, the immersion probe2is removed from the converter furnace100, disconnected from the sublance1, and then discarded.

Referring toFIG. 2, an assembly comprising an immersion sublance1and an immersion probe2is shown in one configuration of the present invention, wherein the connection between both elements constituting the assembly is shown in detail.

When the immersion sublance1is used for measurement of molten metal50(seeFIG. 1), the measurement is performed using sensors21located at the end of the immersion probe2to be immersed in the molten metal50(seeFIG. 2). Generally, the sensors21are connected to a measuring instrument (not shown), located in the surrounding environment of the converter furnace100. The connection between the sensors21and the measuring instrument (not shown) being realized by contact lines that run through the inside of the immersion probe2and the immersion sublance1up to the external environment. After the measurement, the immersion probe2is removed from the converter furnace100, disconnected from the sublance1, and then discarded.

In implementation, where the immersion sublance1is used to take samples of the molten metal50(seeFIG. 1), the samples are collected in a chamber22located at the end of the immersion probe2to be immersed in the molten metal50(seeFIG. 4). After the sampling, the molten metal50that has been collected is removed from the converter furnace100for further analysis, the immersion probe2is disconnected from the sublance1, and then discarded.

Alternatively, the immersion sublance1can simultaneously perform measuring and sampling of the molten metal50using the chamber22and the sensors21as previously described.

In order to provide a better understanding of the present invention, the immersion sublance1and the immersion probe2are first described separately, and then the connection of both elements to form an immersion assembly comprising the immersion sublance1and the immersion probe2will be described.

One configuration of an immersion sublance1is shown inFIGS. 3aand3b.

FIGS. 3aand 3bshow the mechanical structure of the immersion sublance1, the sublance1comprising a guide16and a sublance holder10.

In one configuration of the present invention, the guide16has a substantially cylindrical/tubular shape, being hollow along its whole length. Such a configuration creates an internal cavity for the passage of contact lines connected to sensors21(seeFIG. 2) up to the surrounding environment and subsequently to a measuring instrument (not shown).

The aforementioned guide16may be made from metallic materials able to withstand the typical high temperatures (e.g., 1600 to 1750° C.) of a converter furnace100.

Still referring toFIGS. 3aand 3b, in one configuration, the guide16has a guide connecting end16aon its portion that is closest to the molten metal in the converter furnace100during use. As shown, the guide connecting end16ais coupled to the sublance holder10of the sublance1.

The sublance holder10can have a substantially cylindrical/tubular shape, and the sublance holder10can extend longitudinally from a first coupling end10a, in a direction of the bottom of the converter furnace100, down to a second coupling end10b.

It can be observed that the first coupling end10ais coupled to the guide connecting end16a, such that the diameter of the guide connecting and16ais equal to the external diameter of the first coupling end10a, thus presenting a perfect coupling.

Regarding the second coupling end10b, as described below, it presents an external diameter similar to the external diameter of the internal cavity of the immersion probe2.

Referring toFIG. 3b, in one configuration, an internal cavity of the immersion sublance1is located at the second coupling end10b. Furthermore, the internal cavity can feature at least one holder contact line25c(seeFIG. 7a), at least one of the holder contact lines25cbeing arranged circumferentially around the inner wall of the internal cavity of the sublance holder10at the second coupling end10b. At least one holder contact line25cis connected to the measuring instrument located in the surrounding environment of the converter furnace100.

The immersion sublance1having been described above, the immersion probe2will now be described below. In one configuration, the immersion probe2is illustrated inFIG. 4.

FIG. 4shows the mechanical structure of the immersion probe2, the immersion probe comprising a casing12, an adjustable portion11, and a sensing head20.

The casing12of the immersion sublance2can be made from cardboard and can feature different lengths or diameters, these being dimensioned according to the user.

The casing12is designed with several layers of cardboard, such that the casing12of the immersion probe2does not completely disintegrate when the immersion probe2is immersed into molten metal50(seeFIG. 1). Considering that the immersion lasts a few seconds, the structure of the casing12formed of several layers of cardboard is able to withstand the typical high temperatures (e.g., 1600 to 1700° C.) of a converter furnace100.

In one configuration, the casing12features a substantially cylindrical/tubular shape along its whole length, such a configuration allowing the creation of an internal cavity to receive the adjustable portion11, the internal diameter being wide enough to receive the above referred to adjustable portion11.

Furthermore, it can also be observed fromFIG. 4that, in one configuration, the casing12comprises a casing upper portion12aand a casing lower portion12b. Considering that both portions12aand12bfeature the same diameter, it is observed that an intermediate portion of the casing12features a smaller diameter.

Alternatively, as shown inFIGS. 10 and 11, the casing12can feature a constant diameter along its whole length.

Still referring toFIG. 4, the adjustable portion11extends longitudinally along the inside of the internal cavity of the casing12from a connecting portion11ato a fixed portion11b. The connecting portion11ais located close to the casing upper portion12a, and the fixed portion11bis located close to the casing lower portion12b. The connecting portion11aand the fixed portion11bare associated to one another by means of an elastic portion11c, such that the adjustable portion11features a variable length.

In one configuration, it is observed that the connecting portion11aand the fixed portion11bfeature a substantially cylindrical/tubular shape comprising diameters smaller than or equal to the internal cavity of the casing12.

The elastic portion11ccan comprise a spring, an elastic ring, an elastomer, or any other elastic material, able to compress and expand self by means of applying a force once a first contact point P1is established, as shown inFIGS. 5a-5e, 6a-6e, and 7a-7d, and that will be subsequently described in detail below.

Still referring toFIG. 4, the connecting portion11acomprises a connection base14and a connector15. The connection base14is located at the end of the connecting portion11athat is closest to the bottom of the converter furnace100when in use. The connector15is located at the end of the connecting portion11athat is closest to the top of the converter furnace100when in use. The connection base14is attached to the connector15and the elastic portion11c. The connector15extends from the connection base14of the connecting portion11athe direction of the top of the converter furnace100when in use.

In one configuration, as shown inFIGS. 7ato 7d, the connector15is provided with at least one connector contact line25b, the at least one connector contact line25bbeing circumferentially located around the surface of the connector15. As further described below, the at least one connector contact line25bof the connector15will be connected to at least one holder contact line25cof the sublance holder10when the immersion probe2is connected to the immersion sublance1.

The dimensions of the connector15can be such that the connector15has a substantially smaller diameter than the connection base14, and the connector15can have a diameter smaller than or equal to the diameter of the second coupling end10b. The base14in turn presenting a diameter smaller or equal to the one of the second coupling end10bof the sublance holder10of the immersion sublance1. Such configuration provides a good connection between the immersion sublance1and the immersion probe2, as further described below.

Referring again toFIG. 4, the fixed portion11bextends from the elastic portion11ctowards the bottom of the converter furnace100when in use, and the fixed portion11bis coupled to the casing lower portion12b. The sensing head20is also coupled to the casing lower portion12b.

In one configuration, as shown inFIG. 9, the sensing head20comprises at least one sensor21, which could either be a temperature sensor, an oxygen sensor, or any other sensor useful-for molten metal chemical analyses. At least one sensor21is provided with at least one sensor contact line25a, the sensor contact line25aextending up through the fixed portion11band the elastic portion11cto the connecting portion11a, where the sensor contact line25ais connected to at least one connector contact line25b(seeFIG. 10).a1

Additionally, the sensing head20can comprise a sampling chamber22, the sampling chamber being configured to collect molten metal50when the immersion probe2is immersed, the collected molten metal50solidifying when the immersion probe2is taken out of the converter furnace100.

The immersion sublance1and the immersion probe2having been described above, the connection between the immersion sublance1and the immersion probe2will now be described below, such connection resulting in an assembly comprising the immersion sublance1and the immersion probe2.

During steelmaking processes in a converter furnace100, the user must connect a new immersion probe2to the immersion sublance1, this constituting an assembly of the immersion sublance1and the immersion probe2.

Referring toFIGS. 5ato 5eand 6ato 6a, the connection of the immersion probe2to the immersion sublance1is show in a step-by-step manner, the main focus being only the guide connecting end16aof the immersion sublance1.

FIGS. 5aand 6aillustrate a case where the immersion sublance1and the immersion probe2are completely disconnected. An arrow A represents the direction of motion of the immersion probe2and/or the immersion sublance1toward each other, typically performed by a user, to effect the connection of the elements.

Once the immersion probe2has been moved in the direction of connection A, for example, the sublance holder10of the immersion sublance1is connected to the immersion probe2. More specifically, the second coupling end10bof the sublance holder10extends into the internal cavity of the immersion sublance2towards the adjustable portion11, as shown inFIGS. 5band 6b. As previously noted, the external diameter of the second coupling end10bis smaller than or equal to the internal cavity of the immersion probe2.

Considering that the connector15features a diameter equal to or smaller than the internal diameter of the second coupling end10b, the connector15will extend towards and then into the internal cavity of the second coupling end10b(seeFIGS. 5cand 6c).

As shown inFIGS. 5b-5dand 6b-6d, the connector15will progressively extend into the internal cavity of the second coupling end10buntil the distal surface of the second coupling end10bestablishes a first contact point P1with the proximal surface of the connection base14of the connecting portion11a.

Such first contact point P1is established by the connection base14of the connecting portion11a, which has a diameter equal to the external diameter of the second coupling end10b.

Still referring toFIGS. 5a-5eand 6a-6e, considering the movement of the immersion probe2in the direction of connection A, and the establishment of the first contact point P1, the elastic portion11cwill be compressed by further movement along direction A, and the length of the adjustable portion11will vary.

Furthermore, referring to fromFIGS. 7a-7d, a detailed view of the connection between the connector15and the coupling end10bis shown, as well as the connection of the connector contact lines25band the holder contact lines25c. When the connector15is positioned in the internal cavity of the coupling end10b, the connector contact lines25bof the connector15connect themselves to the holder contact lines25clocated in the internal cavity of the coupling end10bof the sublance holder10. Such connection can be observed fromFIGS. 7band 7c. Still, it can be noted fromFIGS. 7band 7cthat a connection between the respective contact lines25band25cis realized when the first contact point P1is established.

The elastic portion11cis compressed until the casing upper portion12ais connected to the guide connecting end16a, as shown inFIGS. 5e, 6e, and 8d, where a second contact point P2will be established.

A first contact point P1and a second contact point P2are established in the connection between the immersion sublance1and the immersion probe2such contact points P1, P2establishing a connection to form the assembly of the immersion sublance1and the immersion probe2. The assembly comprises an electrical connection between the respective contact lines25band25c, and a mechanical connection between the casing upper portion12aand the guide connecting end16a.

After the connection of the immersion sublance1to the immersion probe2, the assembly is ready to be used in the converter furnace100(seeFIG. 1). Because of the use of the assembly in the inside of a converter furnace100, the immersion sublance1can suffer deformations such as previously described.

As previously mentioned, the sublance holder10, when exposed to high temperatures (e.g., 1600 to 1750° C.) and multiple, successive immersions, can suffer deformations, presenting radial or longitudinal variations.

Such longitudinal or radial variations are compensated for by the elastic portion11cof the immersion probe2of the present invention. The exchange of the immersion sublance1thus not being required after being deformed, making it useable multiple limes with new immersion probes1. The adjustable portion11features a length that varies with the length of the sublance holder10of the sublance1.

The elastic portion11cfeatures a spring tension effect that is superior to the force required by the connector15on the second coupling end10b. Furthermore, the elastic portion11cfeatures a spring tension effect that is inferior to the force required for the connection of the adjustable portion11of the immersion probe2to the sublance holder10of the sublance1.

It is observed that even if the sublance holder10of the immersion sublance1was slightly deformed, the connection of the connector15to the second coupling end10bcould be accomplished because the elastic portion11callows the connector15to move along the longitudinal direction of the immersion probe2.

Furthermore, the compensation of longitudinal or radial variations accomplished by the elastic portion11callows the user to use immersion sublances1that feature variations in connection length. In addition, considering that the casing12can be made out of cardboard and can have longitudinal or radial variations depending on the climatic conditions, as well as the storage location of the immersion probes, the elastic portion11cwill also compensate for such variations.

Various features and characteristics of the invention are described in this specification and illustrated in the drawings to provide an overall understanding of the invention. It is understood that the various features and characteristics described in this specification and illustrated in the drawings can be combined in any operable manner regardless of whether such features and characteristics are expressly described or illustrated in combination in this specification. The Inventor and the Applicant expressly intend such combinations of features and characteristics to be included within the scope of this specification, and further intend the claiming of such combinations of features and characteristics to not add new matter to the application. As such, the claims can be amended to recite, in any combination, any features and characteristics expressly or inherently described in, or otherwise expressly or inherently supported by, this specification. Furthermore, the Applicant reserves the right to amend the claims to affirmatively disclaim features and characteristics that may be present in the prior art, even if those features and characteristics are not expressly described in this specification. Therefore, any such amendments will not add new matter to the specification or claims, and will comply with the written description requirement under 35 U.S.C. § 112(a). The invention described in this specification can comprise, consist of, or consist essentially of the various features and characteristics described in this specification.