SLAG CAP

Abstract

A sampling device for molten metals includes a carrier tube having an immersion end and a sample chamber arranged in the carrier tube. The sample chamber has an inflow conduit. The inflow conduit has an inflow opening inside the sampling chamber and an outer open end which is surrounded by a protective cap. The protective cap has a metallic body with an inner side directed toward the inflow conduit and an outer side. A layer of a material is arranged at the outer side of the metallic body. The material comprises a compound which decomposes and forms water vapor if immersed in molten steel, molten iron or molten slag.

Claims

1. A sampling device for molten metals comprising: a carrier tube having an immersion end; and a sample chamber arranged in the carrier tube and having an inflow conduit, the inflow conduit having an inflow opening inside the sampling chamber and an outer open end which is surrounded by a protective cap, the protective cap having a metallic body with an inner side directed toward the inflow conduit and an outer side, wherein a layer of a material is arranged at the outer side of the metallic body, and wherein the material comprises a compound which decomposes and forms water vapor if immersed in molten steel, molten iron or molten slag.

2. A sampling device according to claim 1, wherein the compound of the material of the layer comprises at least one metal hydroxide, at least one hydrated metal salt, or a mixture of the at least one metal hydroxide and the at least one hydrated metal salt.

3. A sampling device according to claim 1, wherein the compound of the material of the layer comprises a binder preferably a water glass binder.

4. A sampling device according to claim 1, wherein the compound of the material of the layer is aluminum hydroxide or magnesium hydroxide.

5. A sampling device according to claim 1, wherein the compound of the material of the layer is calcium hydroxide.

6. A sampling device according to claim 1, further comprising a housing of a refractory material arranged at the immersion end of the carrier tube, wherein the inflow conduit and the sampling chamber are at least partially arranged in the housing.

7. A sampling device according to claim 6, wherein the protective cap is arranged at the housing.

8. A sampling device according to claim 1, further comprising a sensor, preferably a temperature sensor or an electrochemical sensor, arranged at the immersion end of the carrier tube.

9. A cap having a metallic body with an inner side and an outer side, wherein a layer of a material is arranged at the outer side of the metallic body, and wherein the material comprises a compound and/or a binder which decomposes and forms water vapor if immersed in molten steel, molten iron or molten slag.

10. A cap according to claim 9, wherein the compound of the material of the layer comprises at least one metal hydroxide, at least one hydrated metal salt, or a mixture of the at least one metal hydroxide and the at least one hydrated metal salt.

11. A cap according to claim 9, wherein the compound is aluminum hydroxide or magnesium hydroxide.

12. A cap according to claim 9, wherein the compound is calcium hydroxide.

13. A cap according to claim 9, wherein the compound is water glass.

14. Use of a cap according to claim 1 as a protective cap of a sampling device or a sensor device.

15. A material for use as a layer, preferably as a layer of a cap according to claim 9, wherein the material comprises a compound which decomposes to form water vapor if immersed in molten iron, molten steel or molten slag.

16. A material according to claim 15, wherein the compound comprises a binder, preferably a water glass binder.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0023] The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0024] FIG. 1 shows a schematic view of a sampler according to an embodiment of the present invention; and

[0025] FIG. 2 shows details of an inventive sampler.

DETAILED DESCRIPTION OF THE INVENTION

[0026] According to the present invention, a refractory housing 9, preferably made of cordierite, of the sampler is arranged at the immersion end of a cardboard carrier tube 4. At the outer surface of the immersion end of the cardboard tube 4, a cardboard sleeve 10 is arranged, which is covered by a non-splash sleeve 11 (FIG. 1). The immersion end of the non-splash sleeve 11 is surrounded by an adhesive tape 12. Two mold halves 1 of a sampling chamber and an inflow conduit 3 (FIG. 2) are mounted in the refractory housing 9. Attached to the immersion end of the refractory housing 9 is an outer protective cap 6, coated by a layer 5 of a water vapor forming compound.

[0027] Mating molds halves 1 of the sampling chamber to receive molten metal are held together by a dip 7. An elongated portion of the mold halves 1 receives the inflow conduit 3 which is fixed by cement 8. The mold halves 1 and the inflow conduit 3 are cemented into the refractory housing 9, which is held by the cardboard carrier tube 4, for immersion. The inflow conduit 3 is closed by an inner cap 2, preferably formed of ultralow carbon steel. Attached to the housing is the outer projectile cap 6, which has an inner side which is directed toward the housing and the inflow conduit 3, and an outer side coated by a layer 5 of a water vapor forming compound, preferably aluminum hydroxide. The layer 5 has a thickness of 0. to 0.5 mm.

[0028] A first example of a suitable coating layer 5 may contain between 35 to 55 g aluminum hydroxide powder, preferably 45 g aluminum hydroxide powder, may have a powder size of 20 to 40 m, preferably 30 m and may contain 50 to 100 g, preferably 70 g, water glass of approximately 38 Baum (1.35 g/ml). The water glass has a weight ratio modulus SiO.sub.2/Na.sub.2O of about 3.65.

[0029] A second example of a suitable coating layer 5 may contain between 35 to 55 g aluminum hydroxide powder, preferably 45 c aluminum hydroxide powder; 30 to 50 g. preferably 40 g, silica sand having an average grain sin of about 47 m and a density of about 1.15 g/cm.sup.3; and 120 to 160 g, preferably 140 g, water glass of approximately 38 Baum (1.35 g/ml). The water class has a weight ratio modulus SiO.sub.2/Na.sub.2O of about 3.65.

[0030] A third example of a suitable coating layer 5 may contain between 40 to 60 g magnesium hydroxide powder, preferably 50 g magnesium hydroxide powder; 30 to 50 g, preferably 40 g, silica sand having an average grain size of about 47 m and a density of about 1.15 g/cm.sup.3; and 120 to 160 g, preferably 140 g, water class of approximately 38 Baum (1.35 g/ml). The water glass has a weight ratio modulus SiO.sub.2/Na.sub.2O of about 3.65.

[0031] A fourth example of a suitable coating layer 5 may contain 100 g of a powder of between 40 to 60% by weight magnesium hexahydrate powder, MgCl.sub.2.6H.sub.2O, of a density of approximately 1.57 g/cm .sup.3, preferably 50% by weight magnesium hexahydrate powder, 40 to 60% by weight, preferably 50% by weight, silica sand of a density of about 1.15 g/cm.sup.3; and a liquid binder of potassium silicate, 120 to 160 g, preferably 140 g with a weight ratio of K/Na.sub.2O of 2.5.

[0032] A fifth example is a mixture of (1) 1040 g aluminum hydroxide, (2) 800 g sand, (3) 2800 g sodium silicate and (4) 130 g water. The water lowers the viscosity and leads to easier application of the layer. The layer will be dried, wherein the water as well as some water of the sodium silicate will be removed. The coating of the final product has a composition of (1) 1040 g aluminum hydroxide, (2) 800 g sand and (3) 2366 g sodium silicate (with (4) water being 0 g after drying). The percentage of the three main components (1), (2) and (3) is preferably in the range of (1) from 20 to 25% by weight, (2) from 15 to 20% by weight and (3) from 55 to 65%, respectively, by weight of the total weight of these three components.

[0033] One skilled in the art of coating will understand that the wetting coefficient of silicate binders decreases as the viscosity increases. Control of the viscosity of the coating is a practical matter known in the art whereas aside from adding relatively small additions of water to the mixture, the viscosity can also be reduced by small additions of potassium hydroxide or by simply increasing the liquid temperature, As such, deviations from the prescribed ratio of solids to liquids or small additions to the base mixture to control the viscosity are tolerated without departure from the scope of the present invention.

[0034] Preferably 2-3 g of coating can be applied by conventional dip coating processes and allowed to air dry until dry to the touch.

[0035] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.