Improved sample chamber for molten metals

Abstract

The invention relates to a sample chamber for taking samples from a molten metal bath, in particular a molten steel or iron bath. The sample chamber comprises a flat cover plate and a housing, which are configured to be assembled together along an analysis surface AP to form a sample cavity. The housing comprises an immersion surface and an opposite end surface, and a top surface and a bottom surface. The housing comprises a first opening on the immersion surface and a second opening on another surface. The top surface has at least one recess and consists of a distribution segment, a ventilation segment and an analysis segment, the analysis segment being bounded by the analysis surface AP. The distribution segment and the ventilation segment are arranged below the analysis segment in the direction from the top surface to the opposite surface of the housing, the maximum and minimum cross-sectional areas of the analysis segment perpendicular to the central longitudinal axis X of the housing do not deviate from each other by more than 20%. The invention further relates to a sampler comprising a sample chamber according to the invention and a carrier tube adapted to accommodate at least a part of the sample chamber.

Description

[Technical field]

[0001] The present invention relates to a sample chamber for taking samples from a molten metal bath, in particular a molten steel bath. The present invention further relates to a sampler comprising a sample chamber according to the invention and a carrier tube adapted to accommodate at least a part of the sample chamber. [Background technology]

[0002] During the processing of metals in the molten state, it is necessary to obtain representative samples of the molten metal at various stages of processing, for example for analysis and evaluation of either the chemical composition or metallographic structure of the samples. Different methods are known in the art for analyzing molten metals during production and further processing.

[0003] Historically, the composition of solidified metal samples has often been determined using arc spark optical emission spectroscopy (spark OES) instruments. Spark OES systems are generally the most effective systems for determining the chemical composition of metal samples and controlling the processing of molten metals due to their rapid analysis time and inherent accuracy. Thus, spark OES analysis is commonly used during molten metal processing to control the progress of molten metal production.

[0004] Spark OES excites atoms in a target sample whose composition is of interest, and examines the wavelengths of photons emitted by the atoms during the transition from an excited state to a lower energy state. Each element in the periodic table emits a characteristic set of discrete wavelengths as its atoms return from an excited state to a lower energy state. By detecting and analyzing these wavelengths, the elemental composition of the sample can be determined according to a calibration curve, which shows the relationship between the spectral intensity ratio (i.e., absolute radiant power of element / absolute radiant power of parent material) and the concentration of the element in a standard sample.

[0005] Spectral light may be produced by irradiation with electromagnetic radiation such as laser or X-rays, but generally, in spark OES, it is produced by a short spark generated by a spark generator that is incident on the target whose elemental composition one wishes to know. In this case, the target is a metal sample. Spark generators, their intensity and pulse regimes vary depending on the specific spark OES instrument. It is known that the accuracy and reliability of such emission spectrometers, regardless of the spark energy input, depends on the accuracy and quality of the detectors and optics used to receive the radiation emitted from the sample, and on the homogeneity of the metal sample itself.

[0006] In general terms, the spark OES analysis procedure begins with placing a conductive metal sample, analytical side down, on a predefined area of ​​the stage of a spark OES instrument, i.e., an optical emission spectrometer. More specifically, the sample is positioned to straddle and close the analytical aperture of the spectrometer, with the anode nearly abutting the analytical surface of the sample. Once the desired positioning of the sample, as well as the proximity of the anode and analytical surface, is achieved, a spark is discharged between the anode and the conductive metal sample, which is electrically connected to the spectrometer stage. This connection is most often made by a combination of gravity and a small load. The analytical aperture of the optical emission spectrometer is typically about 12 mm wide. This distance avoids sparks being generated between the anode and the instrument housing. A photodetector receives the emission light from the excavated material on the sample surface. The spark chamber, formed in part by the space between the anode and the metal sample, is continuously purged with argon or other inert gas to avoid air ingress, which would lead to erroneous analytical values.

[0007] In order to lie flat over the analytical aperture of the spectrometer, the metal sample cannot have any extensions and the analytical surface of the metal sample must be smooth. There must be no parts of the sample or sample housing that break the plane of the analytical surface. The sample must straddle the analytical aperture of the spectrometer and have sufficient flatness to facilitate inert gas purging of the spark chamber and present a continuous sample surface toward the anode.

[0008] Procedures and procedures for obtaining representative analyses of metals are well known in the art, such as those described in Dulski, TRA Manual for the Chemical Analysis of Metals, ASTM International, 1996.

[0009] Conventional sampling devices are known that provide coupons or disks of solid metal for use in spectroscopic analysis. The geometry and dimensions of the solidified metal coupons obtained by such sampling devices may be specific to the type of metal or metallographic needs. A common category of samples obtained with immersion devices for spark OES analysis are samples having a disk or oval shape, and a diameter or length of 28 to 40 mm. Most commonly, such samples have a diameter or length of about 32 mm, and a thickness of 4 to 12 mm. Some samplers, commonly known as lollipop samplers, can produce samples of different shapes, from circular to oval or longer, depending on the user's requirements, but most samples still have a diameter or length of about 32 mm. Other samplers, commonly known as dual thickness samplers, combine two thicknesses within the same sample.

[0010] A typical sampling device designed to obtain a sample of molten metal for analysis by spark OES includes a sample chamber or mold cavity configured to fill with molten metal upon immersion of the sampling device into a bath of molten metal. The mold defining the mold cavity or sampling chamber is typically either a two-piece clamshell-type arrangement or a ring covered on the top and bottom by flat plates. Once the metal sample has solidified, the mold is discarded, the sample is cooled and transported to a laboratory, the analytical surface is ground, and upon further cooling, the sample is transported to the spark OES for analysis.

[0011] US Patent No. 3,646,816 describes this type of expendable immersion sampler, where both flat surfaces of the disk-shaped sample are formed by chill plates, providing a pair of smoother surfaces that allow for more rapid freezing and require less cleaning before analysis. Other prior art patents, such as US Patent No. 4,211,117, relate to similar concepts, while US Patent No. 4,401,389 and US Patent No. 5,415,052 show examples of combining this metallurgical sampler with other sensors, one of which may be a temperature measurement sensor.

[0012] Samples produced by conventional sampling equipment have a diameter of approximately 32 mm in the direction parallel to the spectrometer aperture and a thickness of 4-12 mm in the direction perpendicular to the spectrometer aperture. It has been found that solidified samples of conventional thickness require surface grinding of 0.8-5 mm of the as-cast surface to obtain an analytical surface free of metallic and non-metallic segregation. Conventional samples can achieve this surface condition only after preparation processing to produce a geometry in which the diameter in the direction parallel to the spectrometer aperture is typically at least 28 mm and the thickness in the direction perpendicular to the aperture is typically less than 12 mm. This post-preparation geometry is often handled by pre-analysis preparation equipment that mechanically grinds the sample surface, and is also convenient for handling by robotic manipulators that advance the sample from preparation through analysis to removal to await the next sample.

[0013] Eliminating the need for surface preparation reduces analysis time, which is economically advantageous for metal manufacturers. Various solutions to this problem are described in EP 3336511, EP 3336512, EP 3336513, EP 3336514, EP 3581913, and EP 3581914. These documents relate to direct analysis (DA) samplers, a type of molten metal immersion sampler that produces DA samples. Because DA samples do not require any type of surface preparation before being analyzed, the use of spark OES analysis can provide significant economic benefits, both in terms of timely chemical results and time saved in the laboratory.

[0014] In the aforementioned prior art, a sample chamber geometry with different segments is described that allows homogeneous distribution and rapid cooling of the molten metal sample. In particular, the sample chamber includes two zones with different thicknesses that constitute the surface that is subsequently placed in the spectrometer during analysis, i.e. the analytical surface of the obtained sample.

[0015] However, the DA samples obtained with these sample chambers and with the aforementioned prior art DA samplers still suffer from drawbacks such as poor fixation of the sample in the sample chamber, non-flat analytical surface and / or uncontrolled or partial filling. Due to the segmented analytical surface with rather "thin" zones, complete filling of the analytical surface does not result under all circumstances, e.g. in lower temperature applications. Such segments that are not completely filled may result in split surfaces complicating the following analysis. In particular, the seal with the spectrometer may be hindered and parts of the obtained sample may detach and contaminate the spectrometer. Furthermore, the machining of such samplers requires high precision and several process steps.

[0016] It is therefore an object of the present invention to provide an improved DA sample chamber and, accordingly, to improve the quality of the DA sample obtained. It is also an object of the present invention to provide a sampler for use in such a sample chamber. Summary of the Invention

[0017] The present invention relates to a sample chamber for taking samples from a molten metal bath, in particular a molten steel bath, comprising a flat cover plate and a housing, - the flat cover plate and the housing are configured to be assembled together along an analytical surface AP to form a sample cavity; - the housing has an immersed surface and opposing end surfaces and a top surface and a bottom surface, the top surface and the bottom surface extending between the immersed surface and the opposing end surfaces; - the housing has a first opening on the immersion surface and a second opening on another surface; - the upper surface has at least one recess; the cavity includes a distribution segment, a ventilation segment and an analysis segment, the analysis segment being bounded by an analysis plane AP; - the distribution segment, the analysis segment, and the ventilation segment are in flow communication with each other and with the first opening and the second opening of the housing; In the sample chamber, - the distribution segment and the ventilation segment are arranged below the analysis segment in a top-to-bottom direction; - the maximum and minimum cross-sectional areas of the analyzed segment perpendicular to the central longitudinal axis X of the housing do not deviate from each other by more than 20%; A sample chamber comprising:

[0018] Advantageously, the configuration of the sample cavity, in particular the limited deviations in the cross-sectional area of ​​the analytical segment along the length of the housing and the complete placement of the two adjacent segments below this segment, allows to obtain a sample that completely fills the sample plane of the analysis zone. The sample is therefore optimally suitable for analysis without any risk of detachment of parts that could penetrate into the spectrometer or of an insufficient seal between the sample and the spectrometer. Furthermore, the formation of fluid lines that solidify at the analytical surface can be minimized, further increasing the accuracy of the analysis. In addition, the analytical surface obtained is very smooth, further improving the quality of the obtainable data. The geometry of the OES spectrometers applied to the analysis of these types of samples requires a precise distance between the sample plane and the optical components of the spectrometer. A corrugated sample surface therefore has a significant negative effect on the obtainable data.

[0019] Further advantages of this sample chamber design are its mechanical stability and ease of manufacture: the configuration of the distribution and ventilation segments allows for drilling of these segments, eliminating the need for milling as in conventional designs.

[0020] The present invention relates to a sample chamber for taking samples from a molten metal bath for direct analysis (DA) by optical emission spectroscopy (OES).

[0021] As used herein, the term "molten metal bath" is used to describe the melt in a furnace, particularly in a vessel. An alternative term to "molten metal bath" known to those skilled in the art is "metal melt." The molten metal of the molten metal bath is not particularly limited. According to a preferred embodiment, the molten metal bath is a molten steel bath.

[0022] The temperature of the metal melt varies and usually depends on the composition of the metal and the stage of the melting process. According to a preferred embodiment, the temperature of the molten metal bath is in the range of 1500-1800 °C, more preferably in the range of 1500-1700 °C.

[0023] The sample chamber comprises a flat cover plate and a housing, configured to be assembled together to form a sample cavity. In other words, the flat cover plate closes the hollow volume of the housing and forms the sample cavity of the sample chamber. The sample cavity is configured to receive the molten metal and should be understood as the volume into which the molten metal is introduced during sampling.

[0024] The flat cover plate and the housing are configured to be assembled together along an analysis plane AP, in other words the analyzable surface of the sample, obtained when the sample chamber is filled with molten metal, is located in the analysis plane AP.

[0025] A "flat" cover plate should be understood as being essentially flat, i.e., without any depressions or indentations that would provide a hollow volume for the sample when the sample chamber is assembled. As will be appreciated by those skilled in the art, a flat cover plate can still include parts that may be required for assembly, such as rims, protrusions, recesses, etc.

[0026] The flat cover plate may or may not be formed of the same material as the housing. For example, the flat cover plate may be formed of fused silica or a refractory ceramic material. Preferably, the flat cover plate is formed of the same material as the housing.

[0027] The housing is preferably formed from one or more materials that have good thermal and electrical conductivity, such as, but not limited to, aluminum, copper, and other metals with similar thermal and electrical conductivity properties. Preferably, the housing is made from aluminum.

[0028] The mass of the flat cover plate preferably accounts for 10-20% of the total mass of the sample chamber.

[0029] The flat cover plate has a first side or face and an opposing second side or face. The flat cover plate preferably has a thickness extending from the first face to the second face of between 1 mm and 5 mm. The first face of the flat cover plate is configured to face the housing, more specifically a top face of the housing, in the assembled configuration of the sample chamber.

[0030] The flat cover plate preferably has approximately the same width and length as the housing, however, it will be understood that the flat cover plate is not limited to such dimensions and may have a width and length that is greater or less than the housing.

[0031] The sample chamber according to the present invention comprises a housing, which may also be referred to as a sample chamber body. It is to be understood that the housing is not flat like a flat cover plate, but comprises a body having a certain height that encloses a hollow volume.

[0032] The housing includes an immersion surface and an opposing end surface. Those skilled in the art will appreciate that the phrase "immersion surface" refers to the surface or side at the end of the housing that is first immersed in the molten metal in the immersion direction during operation. The immersion surface and the opposing end surface may be parallel to one another.

[0033] The housing also comprises a top surface and a bottom surface extending between the immersed surface and the opposing end surface. The top surface may also be referred to as the upper side of the housing. The bottom surface should be understood to be the opposite of the top surface. The bottom surface is preferably parallel to the top surface. It should be understood that the top surface and the bottom surface are not arranged parallel to the immersed surface and / or the opposing end surface. In other words, an axis perpendicular to the central longitudinal axis X of the housing that intersects the immersed surface or the opposing end surface cannot be parallel to the immersed surface and / or the opposing end surface.

[0034] The upper surface may intersect with the immersed surface at an angle of 90° to 140°, preferably at an angle of 90°, in the latter case the immersed surface and the upper surface are arranged perpendicularly.

[0035] The upper surface can intersect with the opposite end surface at an angle of 90° to 140°, preferably at an angle of 90°, in the latter case the immersed surface and the opposite end surface are arranged perpendicularly.

[0036] The top surface is the analytical surface and is preferably the geometric side of the housing configured to be placed face-down on the stage of an optical emission spectrometer during analysis.

[0037] Typically, the housing is formed as a rectangular solid. Such a housing can be machined from a single piece of material.

[0038] The housing preferably has a length of 30 to 70 mm. The housing may have a width of 20 to 70 mm. The length should be understood as the length from the immersion surface to the opposite end surface, and the width should be understood as perpendicular to the length.

[0039] Throughout this application, length is defined as the dimension parallel to the central longitudinal axis X in the direction from the immersion surface to the opposite end surface of the housing. Width is defined as the dimension perpendicular to the longitudinal axis X and parallel to the top surface, i.e., the analysis surface AP. Depth or thickness is defined as the dimension perpendicular to the longitudinal axis X and perpendicular to the top surface, i.e., in the direction from the top surface to the bottom surface of the housing. More specifically, depth is measured from a point in the analysis surface AP to the lower end or boundary of each segment, as specified below. The dimensions of the cross-sectional areas described herein correspond to the width dimension multiplied by the depth dimension.

[0040] The housing has a first opening on the submerged surface and a second opening on another surface. The other surface may be any other surface of the housing except the top surface. The sample cavity extends from the first opening to the second opening of the sample chamber. It is understood that when the sample chamber is utilized to take a sample from the molten metal, the flow direction of the molten metal is from the submerged surface to the other surface.

[0041] Preferably, the assembled sample chamber comprises only two openings, namely a first opening and a second opening.

[0042] The first opening is preferably configured to receive an inlet conduit, which allows the inlet of molten metal from a molten metal bath into the sample chamber, in particular the sample cavity.

[0043] In a preferred embodiment, the second opening is configured to receive a gas coupling. A gas port may be provided in the face of the housing that includes the second opening, and the gas port is preferably contained entirely within the housing.

[0044] The first and second openings are arranged at a distance from the top surface, i.e. at a distance from the analysis surface AP, which makes it possible to obtain a homogeneous analysis surface for the sample.

[0045] The housing has a top surface with a recess, also called a dent. In other words, a portion of the top surface is hollowed out. It should be understood that the recess in the top surface forms at least a portion of a hollow volume of the housing that includes different segments. These segments collectively form a sample cavity. In particular, the recess includes a distribution segment, an analysis segment, and a ventilation segment. In other words, the housing encloses a hollow volume made up of at least three segments. The distribution segment, the analysis segment, and the ventilation segment are arranged in direct flow communication, sequentially, in the flow direction of the molten metal. The hollow volume of the housing can include additional segments that are not part of the recess in the top surface.

[0046] The distribution segment and the ventilation segment are arranged below the analytical segment in the direction from the top to the bottom of the housing, in particular below the bottom surface BP of the analytical segment, i.e. the ventilation segment and the distribution segment are not connected to the top surface, thus ensuring an ideal and complete filling of the sample chamber in the area of ​​the analytical segment.

[0047] The upper surface preferably includes a single depression.

[0048] In one embodiment, the length of the recess is 20 to 50 mm, preferably 25 to 40 mm.

[0049] It will be understood that the surface area of ​​the housing defining the recess forms the physical boundary of the hollow part of the housing below the top plane, i.e. the analytical surface AP. This surface area is further referred to as the hollow surface of the housing. The convex part of the hollow surface parallel to the analytical surface AP generally consists of a number of regions with different distances to the top plane.

[0050] The distribution segment is a first segment of the cavity in a flow direction of the molten metal during operation. In particular, the distribution segment is located downstream of the first opening. The distribution segment does not connect to the top surface.

[0051] The size of the distribution segment is bounded on one side by the analysis segment. It should be understood that there is no physical delineation between the analysis segment and the distribution segment. However, they are considered as separate segments in the implementation of the present invention. The boundary of the distribution segment is defined on the bottom side by the first part of the hollow surface and on the opposite side by the bottom surface BP of the analysis segment. The boundary on the opposite side should be understood as an imaginary boundary along the extension to the second part of the hollow surface. It should be understood that the second part of the hollow surface is located at a closer distance to the analysis surface than the first part of the hollow surface.

[0052] The central axes of the distribution segments are preferably disposed at an angle of between 45° and 90° to the central longitudinal axis X.

[0053] The distribution segment is further bounded by a side wall. In a preferred embodiment, one of the side walls of the distribution segment intersects with the second portion of the hollow surface at an angle of 40 to 90°, preferably at an angle of 50 to 80°. It is particularly preferred that one of the side walls of the distribution segment intersects with the second portion of the hollow surface at an angle of 60°.

[0054] The cross-sectional area of ​​the distribution segment parallel to the analysis plane AP can have any geometric shape. However, it may be preferable for the cross-sectional area to have a polygonal or circular shape. In particular, a circular cross-sectional area can be produced by a drilling process, which allows easy and accurate machining of the housing.

[0055] The cross-sectional area of ​​the distribution segment can expand in the direction of the metal flow, i.e. the cross-sectional area of ​​the distribution segment increases in the direction from the first opening to the analysis segment. The cross-sectional area of ​​the distribution segment parallel to the longitudinal axis X can be in the range of 8 to 20 mm 2 , preferably 10 to 15 mm 2 The range may be:

[0056] The depth of the distribution segment may range from 1 to 8 mm, preferably from 2 to 6 mm.

[0057] The recess in the upper surface of the housing further includes an analytical segment downstream of the distribution segment and in direct flow communication with the ventilation segment. The analytical segment is preferably disposed above a central longitudinal axis X of the housing.

[0058] The analytical segment is bounded on the upper side by an analytical surface AP, in other words, on one side by a flat cover plate when the sample chamber is assembled and the sample cavity is closed.

[0059] It should be understood that the geometry of the analytical segment at the analytical surface AP is defined by a recess formed in the upper surface of the housing, i.e. the contour of the analytical segment is defined by the contour of the recess. Thus, the analytical segment has an open end at the upper surface and an opposite bottom surface BP. More specifically, the bottom surface BP of the analytical segment is defined in part by the second part of the hollow surface of the housing and in part by a virtual extension of the second part of the hollow surface.

[0060] The maximum and minimum cross-sectional areas of the analysis segment perpendicular to the central longitudinal axis X of the housing do not deviate from each other by more than 20%. This configuration allows the analysis surface AP to be completely filled with the sampled molten metal during operation.

[0061] The cross-sectional area of ​​the analysis segment is to be understood as the cross-sectional area perpendicular to the central longitudinal axis X of the housing and perpendicular to the analysis plane AP. In a preferred embodiment, the maximum and minimum cross-sectional areas of the analysis segment do not deviate from each other by more than 10%, more preferably not by more than 5%.

[0062] In a preferred embodiment, the cross-sectional area of ​​the analysis segment does not decrease after 50% of the length of the analysis segment, more preferably after 70% of the length. Length direction in this context should be understood as the direction from the distribution segment towards the ventilation segment.

[0063] It is preferred that the maximum and minimum cross-sectional areas of the analysis segments are not offset from one another.

[0064] The cross-sectional area of ​​the analysis segment is preferably 2.5 to 10 times the cross-sectional area of ​​the ventilation zone parallel to the analysis plane AP.

[0065] Preferably, the cross-sectional area of ​​the analysis segment is between 5 and 30 mm 2 , more preferably 10 to 25 mm 2 It is.

[0066] The analysis segment may have a maximum depth of 0.5 to 4 mm, preferably 1 to 3 mm. It may be preferred that the analysis segment has a uniform maximum depth. "Maximum depth" is to be understood as the central depth of the analysis segment.

[0067] The depth of the analysis segment may be uniform or may taper towards the edge, in other words the cross-sectional profile of the bottom surface BP of the analysis segment perpendicular to the longitudinal axis X may have any shape, i.e. it may be flat, triangular or concave.

[0068] The width of the analysis segment is preferably constant in the direction of the central longitudinal axis X of the housing. In particular, the analysis segment may have a width of 6 to 14 mm, preferably 8 to 12 mm.

[0069] In a preferred embodiment, the analysis segment has a length of 20 to 50 mm, preferably 25 to 35 mm.

[0070] The ventilation segment is the last segment of the recess in the flow direction of the molten metal. It is in flow connection with the second opening. However, the housing may comprise further segments arranged between the ventilation segment and the second opening.

[0071] The size of the ventilation segment is bounded on one side by the analysis segment. It should be understood that there is no physical delineation between the analysis segment and the ventilation segment. The boundary of the ventilation segment is defined on one side by the bottom surface BP of the analysis segment. This boundary should be understood as an imaginary boundary along the extension of the hollow surface to the second part.

[0072] In some embodiments, the ventilation segment may further bound a third portion of the bottom hollow surface. In such a configuration, the third portion of the hollow surface is disposed at a greater distance to the analysis surface AP than the second portion of the hollow surface. Preferably, the first and second portions of the hollow surface have the same distance to the analysis surface AP.

[0073] The ventilation segments are further bounded by side walls. The cross-sectional area of ​​the distribution segment parallel to the analysis plane, i.e. the cross-sectional area bounded by the side walls, can have any geometric shape. However, it may be preferred that the cross-sectional area has a polygonal or circular shape. In particular, a circular cross-sectional area can be produced by a drilling process, thus allowing easy and precise machining of the housing.

[0074] The central axis of the ventilation segment is preferably disposed at an angle of 45° to 90° relative to the central longitudinal axis X. It should be appreciated that the ventilation segment is not connected to the top surface, i.e., is disposed below the analytical segment. This configuration of the ventilation segment relative to the analytical segment has surprisingly been found to significantly improve the quality of the samples obtained and the associated analytical results, minimizing gas and voids trapped at the analytical surface.

[0075] In certain embodiments, the central axis of the distribution segment and the central axis of the ventilation segment are arranged at an angle of 45° to 90° relative to the central longitudinal axis X, and in a preferred embodiment, both central axes are arranged at an angle of 90° relative to the central longitudinal axis X.

[0076] The ventilation segment may have an elongated shape in a direction perpendicular to the top surface.

[0077] The ventilation segment is preferably located at a distance less than 20% of the length of the analytical segment from the end of the analytical segment, more preferably less than 10%. This arrangement allows the analytical segment to be completely filled before the molten metal sample solidifies. The end of the segment is to be understood as the side of the analytical segment that is closer to the opposite end face than the immersion face, i.e. the side of the housing opposite the immersion face.

[0078] The cross-sectional area of ​​the ventilation segment can taper in the direction of the metal flow, i.e. the cross-sectional area of ​​the ventilation segment can decrease in the direction from the analysis segment to the second opening. The cross-sectional area of ​​the ventilation segment parallel to the longitudinal axis X can be between 0.2 and 5.0 mm 2 , preferably 0.5 to 3.0 mm 2 The range may be:

[0079] The depth of the ventilation segments may range from 1 to 8 mm, preferably from 2 to 6 mm.

[0080] The cross-sectional area of ​​the distribution segment parallel to the analysis surface AP is preferably 0.5 to 2 times the cross-sectional area of ​​the analysis segment. If the cross-sectional area of ​​the distribution segment is too small, the inflowing molten metal will not be slowed down sufficiently and the turbulence will not be reduced, resulting in non-uniform filling of the analysis surface AP.

[0081] The length of the analysis segment in the direction of the central longitudinal axis X of the housing is preferably greater than the depth of the distribution and ventilation segments perpendicular to the central longitudinal axis X.

[0082] In a preferred embodiment, the width of the analysis segment is greater than the width of the ventilation segment, in particular at least three times greater than the width of the ventilation segment.

[0083] The width of the analysis segment perpendicular to the central longitudinal axis X of the housing is preferably greater than the length of the distribution segment and / or the length of the ventilation segment along the central longitudinal axis X.

[0084] The hollow volume of the housing may also comprise an inlet segment configured to receive the molten metal, and / or an inlet conduit, the inlet segment being disposed before the distribution segment in a flow direction of the molten metal and in direct flow communication with the first opening, the central axis of the distribution segment being preferably disposed at an angle of 45° to 90° relative to the central axis of the inlet segment.

[0085] Preferably, the cross-sectional area of ​​the inlet segment perpendicular to the central longitudinal axis X depends on the cross-sectional area of ​​the analysis segment perpendicular to the central longitudinal axis X and / or the cross-sectional area of ​​the distribution segment parallel to the analysis plane AP. The cross-sectional area of ​​the inlet segment is preferably 0.5 to 2 times the cross-sectional area of ​​the analysis segment. In a preferred embodiment, the cross-sectional area of ​​the inlet segment is 0.2 to 0.7 times the maximum cross-sectional area of ​​the distribution segment, thereby reducing the inlet velocity required for metal mixing. If the cross-sectional area of ​​the inlet segment is too small, the inlet molten metal will not be slowed down sufficiently, the turbulence cannot be reduced, and the sample cavity will be insufficiently filled.

[0086] The hollow volume of the housing may also comprise a connecting segment arranged after the ventilation segment in the flow direction of the molten metal and in direct flow communication with the second opening. The connecting segment is preferably configured to receive a gas connecting device. A central axis of the ventilation segment is preferably arranged at an angle of 45° to 90° relative to a central axis of the connecting segment.

[0087] The top surface of the housing may include a ridge protruding therefrom and surrounding the recess, and the flat cover plate preferably lies flush with the ridge of the housing along its top surface when the sample chamber is assembled.

[0088] In a preferred embodiment, the seal member is provided on a first surface of a flat cover plate configured to be located between the housing and the flat cover plate in the assembled configuration of the sample chamber. Advantageously, the seal member prevents dirt from adhering to either the cover plate or the housing, which dirt may contaminate the surfaces of the spectrometer and affect an ongoing or even subsequent analysis.

[0089] The sealing member is preferably an airtight sealing member. More specifically, the sealing member may be a gasket. The gasket may be of any shape.

[0090] The sealing member is preferably constructed of a material that is essentially non-contaminating for the sample in the sample chamber. In one embodiment, the sealing member is formed of silicone or any similar polymer, paper, or cardboard. Those skilled in the art will appreciate that the sealing member may be formed of any material that provides an airtight seal between the flat cover plate and the housing. Those skilled in the art will appreciate that the sealing member may alternatively be formed as an O-ring.

[0091] The sample chamber, particularly the flat cover plate and the housing, may be held together by fasteners, preferably clips or clamps.

[0092] Advantageously, by using clips or clamps to secure the sample chamber, the two parts are secured by the compressive force applied by the fasteners, and no adhesives or cements are used to secure them together.

[0093] In a preferred embodiment, the fasteners are made of metal, however, one skilled in the art will appreciate that the fasteners may be made of another suitable material that can withstand immersion in hot metal and provide the necessary compressive force.

[0094] Preferably, the housing comprises a first coupling means and the fastener comprises a second coupling means, the first and second coupling means being configured to interact with each other. The coupling means of the housing can be realized as at least one recess, preferably two recesses, in the housing. Preferably, the at least one recess is arranged in a face of the housing that is arranged perpendicular to the top face.

[0095] In a preferred embodiment, the fastener is configured to apply a force in a direction perpendicular to the longitudinal axis X of the housing.

[0096] It is preferred that the sample chamber is provided with an identification means. In particular, such an identification means may comprise a non-destructive marking or label, for example such an identification means may be a barcode or a QR code.

[0097] Additionally, the sample chamber may include an inlet conduit configured to be received by the first opening of the housing. The inlet conduit is preferably made from a quartz material, more preferably a fused silica material. However, it will be appreciated that the inlet conduit may be made from any other suitable material, including, but not limited to, a ceramic material.

[0098] The sample chamber can also include a gas coupler configured to be received by the second opening such that the sample chamber can be purged with a gas flow.

[0099] The invention also relates to a sampler comprising a sample chamber according to the invention and a carrier tube adapted to accommodate at least a part of the sample chamber.

[0100] The sampler may further comprise a measurement head supported on the carrier tube and adapted to accommodate at least a portion of the sample chamber. The measurement head is to be understood as a part that accommodates a part that is immersed in the molten metal to obtain measurements and then removed. In other words, the measurement head provides a disposable platform for the immersible part.

[0101] In one embodiment, the sampler includes a protective cap attached to a first end of the inlet conduit. [Brief description of the drawings]

[0102] The following schematic diagrams, in conjunction with some exemplary figures, illustrate aspects of the invention to enhance understanding of the invention.

[0103] [Figure 1]FIG. 1 shows a sampler for taking samples from a molten metal bath. [Diagram 2] FIG. 2 shows the sample chamber housing and cover plate secured by the clamps. [Diagram 3] FIG. 3 shows the housing in a different view. [Figure 4] FIG. 4 shows a side view of the assembled sample chamber. [Diagram 5] FIG. 5 shows the hollow portion of the sample chamber housing in more detail. [Figure 6] FIG. 6 shows, in a front view of the housing, a sample chamber with different possible cross-sectional shapes of the analytical segment.

[0104] FIG. 1 shows a sampler 1 for taking a sample from a molten metal bath. The sampler 1 is suitable for immersion in the molten metal and for extracting a sample therefrom. The sampler 1 shown comprises a measuring head 2, which may be made of resin-bonded silica sand. The measuring head 2 is supported on a carrier tube 3, which may be a paper carrier tube. In use, a probe holder or lance (not shown) is preferably inserted into the internal volume of the carrier tube 3 to provide the mechanical action required to submerge the measuring head 2 below the surface of the bath of molten metal in immersion direction I.

[0105] The measurement head 2 comprises a sample chamber 20 for collection and recovery of a sample of molten metal. As shown, the sample chamber 20 consists of a housing 22 and a flat cover plate 23, as shown in more detail in Figure 2 from a front view perspective.

[0106] The measurement head 2 has a first end and an opposite second end. The first end of the measurement head 2 corresponds to the submerged end 4 of the measurement head. The second end of the measurement head is configured to face the lance or probe holder. The housing 22 of the sample chamber 20 also has a first end 30 and an opposite second end 31. The first end 30 of the housing corresponds to the submerged surface of the sample chamber 20. The skilled person will understand that the phrase "submerged end" refers to the end of the assembly, respectively the sampler, that is initially submerged in the molten metal. The first end 30 of the housing is fitted with an inlet conduit 5, which is received in a first opening 34. The inlet conduit 5 allows the flow of molten metal from the molten metal bath to the sample cavity 21 (not visible in the view shown in FIG. 1).

[0107] In use, the measurement head 2 is immersed in a hot metal bath in an immersion direction I. The inflow direction of the molten metal as it is introduced into the sample chamber 20 and its cavity 21 is therefore opposite to the immersion direction I, parallel to the longitudinal axis X of the sample cavity 21.

[0108] The inlet conduit 5 is covered by a first protective cap 6. The first protective cap 6 is preferably made of metal, more preferably of steel. A second protective cap 7 then covers (more specifically surrounds) the first protective cap 6. The second protective cap 7 is attached to the measurement head 2. The second protective cap 7 is preferably made of metal, more preferably of steel.

[0109] The sample chamber 20 can be purged and pressurized by an inert gas, which is fed towards the inlet conduit 5 via a coupler (not shown) connected to the second opening of the housing. Those skilled in the art will understand that purging with an inert gas is only necessary for certain applications. After the measurement head 2 is immersed under the surface of the hot metal bath, the second protective cap 7 melts due to the heat of the hot metal, thereby exposing the first protective cap 6 to the hot metal. Subsequently, the first protective cap 6 also melts, thereby putting the sample chamber 20 in fluid communication with the hot metal bath. The hot metal then enters the sample chamber, in particular from the immersion end 30 through the first opening 34 to the second end 31, while the gas is exhausted from the sample chamber cavity 21 through the second opening 35.

[0110] As the molten metal freezes in the sample cavity 21, a solidified metal sample is formed that is inseparable from the housing 22. The measurement head 2 is easily destroyed, allowing the sampling chamber 20 to be removed from the carrier tube 3. The clips 8 securing the sample chamber 20, if present, are removed. Unlike conventional sampling devices, the sample remains attached to the sample housing 22. Thus, when referring to metal coupons sent to OES herein, the term "sample" refers to the inseparable combination of the recovered solidified sample and the sample housing 22.

[0111] The housing 22 and cover plate 23 of the sample chamber 20 can be fixed by clips or clamps 8 with sufficient compressive force to resist the tendency of the two parts to separate due to the forces of the molten metal flowing into and filling the sample cavity 21 and the forces during the purge phase before the sample is filled, as also shown in FIG. 2. The clips 8 are preferably made of metal. FIG. 2 shows a front view of the sample chamber, i.e. the immersion surface 30 and the first opening 34 of the housing 22. In the configuration shown in FIG. 2A, the clips 8 are mainly arranged on the cover plate 23. The housing 22 comprises a recess 10 with which the clip can interact. The clips 8 can also be arranged sideways, as shown in FIG. 2B.

[0112] For practical purposes of assembly, the flat cover plate 23 may have approximately the same width and length as the housing 22. A first side of the cover plate 9 is configured to face the housing 22. A seal member (not shown) may be provided on the first side of the cover plate 9 such that in the assembled configuration of the sample chamber 20 it is located between the housing 22 and the cover plate 23.

[0113] FIG. 3 shows the housing 22 according to an embodiment of the invention in different views. In particular, FIG. 3A shows a partial cross-sectional view and FIG. 3B shows a top view of the upper surface 32 of the housing 22 with the recess 40. The segments located below the upper surface and therefore not visible in the shown view are indicated with grey lines. The upper surface 32 shown in the figures is the analytical surface, meaning that it is the geometric side of the housing 22 on which the sample is collected and is therefore configured to be placed downwards on the stage of the optical emission spectrometer during the analysis. During the analysis, an inert gas is purged into the spark chamber of the spectrometer so that there is no leakage between the sample to be analyzed and the spectrometer stage. Furthermore, the analytical surface of the solidified metal sample abutting against the cover plate serves to close the opening of the OES. This surface must therefore be completely filled in order to completely close the opening of the spectrometer. In particular, the front of the molten metal entering the sample cavity should reach at least the ventilation segment before freezing.

[0114] The top surface 32 includes a recess 40 that forms at least a portion of the sample cavity 21 of the sample chamber 20. As shown, the top surface 32 extends between the submerged end or face 30 and the opposing end or face 31 of the housing. Figures 3A and 3B show that the top surface 32 is hollowed out to form different segments of the sample cavity 21 for receiving molten metal, collecting a molten metal sample, and ventilating the cavity. The recess 40 is defined by an elongated shape.

[0115] FIG. 3B also shows where the longitudinal axis X of the housing, the width W and the length L of the recess 40 are. Also visible is the hollow surface of the housing 41, which comprises two further recesses below the plane of the top surface. In the illustrated embodiment, the hollow portion of the housing 22 comprises two additional segments, namely a distribution segment 43 and a connecting segment 46. It should be noted that both segments 43 and 46 are not visible in the portion of the housing shown in FIG. 3A. As shown, the hollow surface 41 comprises all the portion of the housing within the recess 40 as is visible in the illustrated view. In the illustrated embodiment, the opposing ends of the recess 40 (i.e. the leading and trailing ends in the immersion direction I) are rounded to facilitate machining. However, it will be understood by those skilled in the art that the ends may have any shape. In the embodiment of the invention shown in FIG. 3, the top surface of the housing 32 comprises a rim 11. Such a rim can enhance the seal with the cover plate, especially if an additional sealing element is also part of the sample chamber assembly.

[0116] FIG. 4 shows a side view of an assembled sample chamber according to an embodiment of the invention. In FIG. 4A, the sample chamber 20 is shown in an assembled configuration with an inlet conduit 5. A cover plate 23 is disposed on the upper surface 32 of the housing 22 along the analytical surface AP to close the hollow portion of the housing, thereby creating a sample cavity 21. In the illustrated configuration, the inlet conduit 5 communicates with an inlet segment 42 of the sample cavity 21. FIG. 4B shows another embodiment of the invention with a deoxygenation element 12 disposed within the inlet conduit 5.

[0117] FIG. 5 shows in more detail different configurations of the hollow volume, i.e. the sample cavity, of the housing 22 and for certain embodiments the configuration of the different segments of the sample cavity 21 relative to each other. The upper part of the cavity enclosed by the analytical surface AP forms the analytical segment 44. The analytical segment 44 completely overlaps the distribution segment 43 and the ventilation segment 45. The aforementioned three segments form a U-shaped cavity, which is flow-connected to the first opening 34, optionally via the inflow segment 42. The illustrated analytical segment 44 has a uniform depth in the direction of the central longitudinal axis X. The ventilation segment 45 can further be connected to a connecting segment 46 arranged on the opposite side of the housing, as shown in FIG. 5A. In FIG. 5B another configuration is shown, in which the ventilation segment 45 is directly connected to the second opening 35 on the face of the housing opposite to the top face 32, i.e. the bottom face 33. In both embodiments the ventilation segment 45 is arranged flush with the end of the analytical segment 47.

[0118] The analysis segment 44 is bounded by an analysis surface AP on one side and a base surface BP on the other side, both planes being indicated by dashed lines in Fig. 5. The base surface BP is an imaginary plane that extends in part in the plane of the hollow surface along the central longitudinal axis X across the distribution segment 43 and the ventilation segment 45. The central axis of the distribution segment D as well as the central axis of the ventilation segment V are arranged perpendicular to the central longitudinal axis X and to the analysis surface AP in both illustrated embodiments.

[0119] The hollow surface of the housing 22 includes several sections, as shown in the figure. D forms the bottom boundary of the distribution segment 43, and the second part HF A forms the bottom boundary of the analysis segment 44, and the third part HF V forms the bottom boundary of ventilation segment 45. In the configuration shown in Figure 5B, the hollow surface includes only two segments.

[0120] Preferably, when a sample is taken, the molten metal completely fills and freezes in the analysis segment 44, in particular along the analysis surface AP, against the cover plate 23. The illustrated configuration of the segments of the hollow part of the housing ensures that these requirements are met. Minimal cross-sectional deviations along the length of the analysis segment and the complete location of the ventilation segment below this segment ensure that the front of the molten metal entering the sample chamber fills completely before it starts to solidify.

[0121] FIG. 6 shows an embodiment of the sample chamber with different possible cross-sectional shapes of the analytical segment in a front view of the housing 22, i.e. in the direction along the longitudinal axis X, and the relevant parameters used to describe the analytical segment. The cover plate 23 is also shown. It should be noted that the dimensions shown are not necessarily drawn to scale. In FIG. 6A, the cross-section of the analytical segment 44 has a rectangular shape. On the upper side, it is surrounded by the cover plate 23, which also defines an analytical surface AP. On the opposite side, the segment is bounded by a bottom surface BP. As will be understood by those skilled in the art, the cross-sectional area is determined by the width W and depth D of the segment. FIG. 6B shows an analytical segment 44 with a triangular base, and FIG. 6C shows a convex cross-section of the analytical segment 44.

[0122] The features disclosed in the claims, the description and the drawings may possibly be essential to the various embodiments of the claimed invention either separately or in any combination with one another. [Explanation of symbols]

[0123] 1. Sampler 2 Measuring head 3. Carrier tube 4 Immersion end of the measuring head 5 Inflow conduit 6 First protective cap 7 Second protective cap 8 Clips 9 Cover plate first side 10 Recess 11 Rims 12 Deoxidizing element 20 Sample Chamber 21 Sample Cavity 22 Housing 23 Cover plate 30 Submerged end / face of housing 31 Opposite ends / faces of housing 32 Top of housing 33 Bottom of housing 34 First opening of housing 35 Second opening of housing 40 Top recess 41 Hollow surface 42 Inflow Segment 43 Distribution Segments 44 Analysis Segments 45 ventilation segments 46 Combined Segments 47 End of analysis segment I Immersion direction X Central Longitudinal Axis AP analysis side D Central axis of distribution segment V central axis of ventilation segment HF D First part of hollow surface HF A The second part of the hollow surface HF V The third part of the hollow surface

Claims

1. A sample chamber for taking samples from a molten metal bath, in particular a molten steel bath, comprising a flat cover plate and a housing, - the flat cover plate and the housing are configured to be assembled together along an analytical surface AP to form a sample cavity; the housing comprises an immersed surface and opposing end surfaces, a top surface and a bottom surface, the top surface and the bottom surface extending between the immersed surface and the opposing end surfaces; - said housing has a first opening on said immersed face and a second opening on another face; - said upper surface has at least one depression; said cavity comprises a distribution segment, a ventilation segment and an analysis segment, the analysis segment being bounded by an analysis surface AP; the distribution segment, the analysis segment and the ventilation segment are in flow communication with each other and with the first opening and the second opening of the housing; In the sample chamber, the distribution segment and the ventilation segment are arranged below the analysis segment in the direction from the top surface to the bottom surface; the maximum and minimum cross-sectional areas of the analysis segment perpendicular to the central longitudinal axis X of the housing do not deviate from each other by more than 20%; A sample chamber comprising:

2. The sample chamber of claim 1 , wherein the central axis of the distribution segment is disposed at an angle of between 45° and 90° relative to the central longitudinal axis X of the housing.

3. The sample chamber of claim 1 or 2, wherein the central axis of the ventilation segment is disposed at an angle of between 45° and 90° to the central longitudinal axis X of the housing.

4. A sample chamber according to any one of claims 1 to 3, wherein the cross-sectional area of ​​the analytical segment does not decrease over 50% of the length of the analytical segment.

5. The sample chamber of any one of claims 1 to 4, wherein the maximum cross-sectional area and the minimum cross-sectional area of ​​the analytical segment are not offset from one another.

6. The sample chamber according to any one of claims 1 to 5, wherein the cross-sectional area of ​​the analysis segment is 2.5 to 10 times the cross-sectional area of ​​the ventilation zone parallel to the analysis plane AP.

7. The sample chamber of any one of claims 1 to 6, wherein the width of the analytical segment is constant in the direction of the central longitudinal axis X of the housing.

8. The sample chamber according to any one of claims 1 to 7, wherein the analytical segment has a length of 20 to 50 mm.

9. A sample chamber according to any preceding claim, wherein the ventilation segment is positioned at a distance from an end of the analytical segment that is less than 20% of the length of the analytical segment.

10. The sample chamber of any one of claims 1 to 9, wherein the width of the analysis segment is greater than the width of the ventilation segment.

11. A sample chamber according to any preceding claim, wherein the upper surface comprises a single depression.

12. The sample chamber of any one of claims 1 to 11, wherein the assembled sample chamber comprises only two openings.

13. A sampler comprising a sample chamber according to any one of claims 1 to 12 and a carrier tube adapted to accommodate at least a portion of the sample chamber.

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