Molten metal filtration unit

Abstract

The object of the present invention is to provide a molten metal filtration unit that is stably disposed in a filtration chamber. The object is achieved by a molten metal filtration unit that includes a pair of side plates and a substantially cylindrical filtration tube that is connected substantially perpendicularly to each of the pair of side plates, the pair of side plates including a first side plate having a through hole at a location connected to the filtration tube and a second side plate whose location connected to the filtration tube is closed, each side plate including a leg that hangs down from a bottom surface of the side plate, and the number of legs provided on the first side plate is at least one more than the number of legs provided on the second side plate.

Description

[Technical field]

[0001] The present invention relates to a molten metal filtration unit to be disposed in a molten metal filtration apparatus for filtering molten metal such as aluminum, etc. More specifically, the present invention relates to a molten metal filtration unit that facilitates disposing the molten metal filtration unit in a predetermined position in a filtration chamber of a molten metal filtration apparatus. [Background technology]

[0002] Molten metals such as aluminum used in the production of castings usually contain hydrogen and nonmetallic inclusions such as oxides as impurities. For example, hydrogen dissolved in the molten metal forms cavities called porosity in the casting, and oxides and the like can become inclusions in the casting. Both of these cavities and inclusions are undesirable because they can be the starting point for fracture of the casting. Therefore, filtration devices have been developed to filter the molten metal and remove impurities such as inclusions contained in the molten metal.

[0003] To achieve this purpose, a molten metal filtration device is typically used in which a molten metal filtration unit having a plurality of ceramic filtration tubes for filtering impurities from the molten metal is placed in a filtration chamber provided with an inlet and an outlet (see Patent Document 1). In such a molten metal filtration device, when the molten metal filtration unit is placed in the filtration chamber, the molten metal filtration unit needs to be tightly attached to the outlet side of the filtration chamber in order to prevent leakage of the molten metal.

[0004] For this reason, the position and height of the molten metal filtration unit have been adjusted as necessary by using a block for adjusting the height of the molten metal filtration unit on the hearth of the filtration chamber. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-210254 A Summary of the Invention [Problem to be solved by the invention]

[0006] When the filtration chamber of a repeatedly used molten metal filtration device repeatedly filters molten metal, it expands and contracts repeatedly due to the heat of the high-temperature molten metal. In addition, the footrest part (base part) of the hearth that comes into contact with the filtration unit wears out as the filtration unit is repeatedly installed. As a result, the hearth of the filtration device is no longer approximately level due to deterioration over time, making it difficult to stably install the filtration unit within the filtration chamber.

[0007] Therefore, the problem to be solved by the present invention is to provide a molten metal filtration unit that eliminates the above-mentioned inconveniences, i.e., that is, that can be stably arranged in the filtration chamber. Note that throughout this specification, the "molten metal filtration unit" may also be referred to simply as the "filtration unit." Furthermore, throughout this specification, the "molten metal filtration device" may also be referred to simply as the "filtration device." [Means for solving the problem]

[0008] As a result of intensive research, the inventors discovered that the above-mentioned problems could be solved by improving the legs provided on the bottom surfaces of the side plates that constitute the filtration unit, and thus completed the present invention. Note that in the above description and in this specification, the first side plate refers to a side plate that has a through hole at the location connected to the filtration tube, and the second side plate refers to a side plate whose location connected to the filtration tube is closed.

[0009] A typical embodiment of the present invention is as follows. A pair of side panels; a substantially cylindrical filtration tube connected substantially perpendicularly to each of the pair of side plates; A molten metal filtration unit comprising: The pair of side plates are a first side plate having a through hole at a portion connected to the filtration tube; a second side plate having a portion connected to the filtration tube closed; Each side panel has a leg extending downward from the bottom surface of the side panel, The number of legs provided on the first side panel is at least one more than the number of legs provided on the second side panel. The molten metal filtration unit. Effect of the Invention

[0010] According to the filtration unit of the present invention, the number of legs provided on the first side plate is at least one more than the number of legs provided on the second side plate, so that the legs come into contact with the hearth even in a filtration chamber that has deteriorated over time, thereby achieving a stable arrangement of the filtration unit. Furthermore, the filtration unit has an additional excellent advantage in that heat can circulate between the legs, improving the preheating efficiency of the filtration device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 shows a typical example of a filtration unit and a filtration device. [Diagram 2] FIG. 2 shows a schematic diagram of a filtration unit according to one embodiment of the present invention. [Diagram 3] FIG. 3 shows a front view of a first side plate of a filtration unit according to one embodiment of the present invention. [Figure 4] FIG. 4 shows a front view of a second side plate of a filtration unit according to one embodiment of the present invention. [Diagram 5] FIG. 5 is a graph showing the change over time in the controlled temperature by the heater and the change over time in the temperature of the filtration units of Example 1 and Comparative Example 1 in the preheating evaluation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The filtration unit of the present invention is disposed in a filtration chamber of a filtration device for use. In order to facilitate understanding of the characteristics of the filtration unit of the present invention, a typical filtration unit and filtration device will first be described with reference to FIG.

[0013] Fig. 1 shows a filtration device 101, which is equipped with an inlet 102, a filtration chamber 103, a discharge chamber 105, and outlets 106 and 110. The filtration unit 104 is equipped with a first side plate 107, a second side plate 108, and a substantially cylindrical filtration tube 109 connected substantially perpendicularly to the side plates. Although not shown in Fig. 1, the first side plate 107 has a through hole at the location connected to the filtration tube 109, and the second side plate 108 has a portion connected to the filtration tube 109 closed.

[0014] 1 is a schematic diagram of the entire filtration device observed from a direction in which the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube. In this specification, unless otherwise specified, the filtration unit and the filtration device will be described assuming that they are observed from the same direction.

[0015] In molten metal filtering, a filtering unit 104 is disposed in a filtering chamber 103, and molten metal obtained by dissolving metals such as aluminum and aluminum alloys is supplied to the inlet 102. The molten metal supplied from the inlet 102 passes through a filtering tube 109 provided in the filtering unit 104 disposed in the filtering chamber 103, thereby removing impurities such as oxides contained in the molten metal. The filtered molten metal flows from the filtering tube 109 through a through hole provided in the first side plate 107, into the tapping chamber 105 from the tapping outlet 110, and is discharged from the tapping chamber 105 through the tapping outlet 106. The discharged molten metal is sent to a storage device, a metal processing device that processes the molten metal, or the like (neither of which are shown).

[0016] In addition, a refractory material made of SiC aggregate bound with Si3N4 can generally be used as the filtering device 101. The size of the filtering device 101 is not particularly limited as long as the filtering unit 104 can be placed in the filtering chamber 103.

[0017] In the filtration unit of the present invention, each side plate has a leg extending vertically from the bottom surface of the side plate, and the number of legs provided on the first side plate is at least one more than the number of legs provided on the second side plate.

[0018] In such a filtration unit, for example, when the second side plate has one leg, the first side plate has two or three or more legs. When the second side plate has two legs, the first side plate has three or four or more legs. Furthermore, when the second side plate has three legs, the first side plate has four or five or more legs. In addition, when multiple legs are provided on either or both side panels, the multiple legs on each side panel are preferably located symmetrically with respect to approximately the center point in the longitudinal direction of the bottom surface of the side panel. When multiple legs are provided on either or both side panels, the heights (vertical dimensions) of the multiple legs on each side panel are preferably approximately the same.

[0019] Due to the above-mentioned configuration, the filtration unit of the present invention can be stably positioned within the filtration chamber because all of the legs of the filtration unit can be in contact (or substantially in contact) with the hearth even if distortion occurs in the hearth.

[0020] In addition, the filtration device needs to be preheated after the filtration unit is placed and before the molten metal is poured in. The filtration unit of the present invention has the above-mentioned configuration, and since heat can circulate between the legs, it takes less time to reach the target temperature compared to conventional filtration units, and preheating efficiency can be improved.

[0021] Furthermore, when filtration of molten metal is performed using a filtration device, the filtration unit of the present invention has less friction with the hearth than the conventional filtration unit, and is therefore less likely to impede thermal expansion of the filtration unit itself, preventing leakage of the molten metal due to cracks in the filtration unit caused by thermal expansion, and providing high-quality molten metal.

[0022] In one embodiment of the present invention, the filtration unit may have two legs on the first side plate and one leg on the second side plate.

[0023] By configuring the filtration unit in this way, it has three legs. Therefore, the bottoms (vertical lowest point) of the three legs of the filtration unit are on the same plane, and even in a filtration chamber where the hearth has become distorted due to aging, the bottoms of all the legs are in contact with the footrests (base) of the hearth. As a result, the filtration unit can be stably placed in the filtration chamber.

[0024] In one embodiment of the present invention, the molten metal filtration unit may have two legs near both longitudinal ends of the bottom surface of the first side plate, and one leg at approximately the longitudinal center of the bottom surface of the second side plate.

[0025] By configuring the filtration unit in this manner, the filtration unit can be more stably disposed within the filtration chamber.

[0026] In one aspect of the present invention, when the molten metal filtration unit is placed on a horizontal surface and observed vertically from above, the area of ​​the molten metal filtration unit, which is expressed by the product of the length of the molten metal filtration unit in the longitudinal direction of the filtration tube and the longitudinal length of the side plate, is defined as S1, and the total area of ​​the contact areas of all the legs of the molten metal filtration unit is defined as S2. The area ratio S2 / S1 may be 0.0020 or more and 0.015 or less.

[0027] S1 may correspond to the base area when the filtration unit is considered as a rectangular parallelepiped. S2 may be calculated from the dimensions of the bottom surface of the legs when the bottom of the legs is flat. The contact area of ​​the legs may be measured by applying ink to the legs and measuring ink marks, or by placing the filtration unit on pressure-sensitive paper and measuring marks left behind.

[0028] The area ratio S2 / S1 may be 0.0020 or more and 0.015 or less, preferably 0.0020 or more and 0.0133 or less, and more preferably 0.0020 or more and 0.0093 or less. When the area ratio S2 / S1 is within the above range, heat can circulate between the legs, shortening the time required to reach the target temperature and improving preheating efficiency.

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment shown in the drawings.

[0030] FIG. 2 shows a filtration unit according to an embodiment of the present invention. However, in order to explain the present invention, the dimensional ratio and the number of filtration tubes may differ from the actual ones. The filtration unit 104 according to the present invention has a leg 201 on the bottom of the first side plate 107 and a leg 202 on the bottom of the second side plate 108. FIG. 3 shows a first side plate of the filtration unit according to an embodiment of the present invention. That is, FIG. 3 shows the filtration unit in FIG. 2 as viewed from the left side in the figure. FIG. 4 shows a second side plate of the filtration unit according to an embodiment of the present invention. That is, FIG. 4 shows the filtration unit in FIG. 2 as viewed from the right side in the figure.

[0031] Therefore, in one embodiment of the present invention, the first side plate can be provided with two legs 201 as shown in Fig. 3, and the second side plate can be provided with one leg 202 as shown in Fig. 4. As described above, such a configuration allows the legs 201 and 202 of the filtration unit to come into contact with the hearth even if distortion occurs in the hearth, so that the filtration unit 104 can be stably arranged in the filtration chamber.

[0032] In addition, in this embodiment, heat can circulate between the two legs 201 in FIG. 3 and from both sides of the leg 202 in FIG. 4, so that the time required to reach the target temperature during preheating is shorter than in conventional filtration units, and preheating efficiency can be improved.

[0033] Furthermore, in this embodiment, two legs 201 can be provided near both longitudinal ends of the bottom surface of the first side panel as shown in Figure 3, and one leg 202 can be provided approximately at the longitudinal center of the bottom surface of the second side panel as shown in Figure 4.

[0034] In this embodiment, as described above, the area ratio S2 / S1 may be 0.0020 or more and 0.015 or less. Here, the area S1 of the molten metal filtration unit is expressed as the product of the length of the molten metal filtration unit in the longitudinal direction of the filtration tube and the longitudinal length of the side plate when the molten metal filtration unit is placed on a horizontal surface and observed vertically from above, and S1 is the product of the total length L of the filtration unit 104 in Fig. 2 and the width W of the side plate in Fig. 3 (or Fig. 4). The total ground contact area of ​​the legs 201 and 202 is S2, and S2 may be calculated from the dimensions of the bottom surfaces of the legs 201 and 202, or the actual ground contact area may be measured using ink or pressure-sensitive paper.

[0035] Although the molten metal filtration unit according to the present invention has been described above by using specific embodiments, it is not intended to be limited to these embodiments. In particular, it should be noted that the molten metal filtration unit according to the present invention can be applied to any molten metal filtration unit as long as it is characterized by at least the number of legs of the side plate. For example, the filtration unit according to the present invention is not limited by the shape, length, number, etc. of the filtration tube. The shape of the legs is not particularly limited, and for example, the bottom surface of the legs may be inclined or a step may be provided on the bottom surface of the legs. The filtration unit according to the present invention is not limited to the filtration unit illustrated in the specific embodiments described above. The scope of the subject matter that can be included in the present invention should be determined by the appended claims.

[0036] <Additional embodiment regarding the structure of the filtration tube> The structure of the filter tube of the molten metal filtering unit according to the present invention is not particularly limited except as defined in the appended claims. The filter tube may satisfy a specific relationship regarding the inventive shape or dimensions as exemplified in the following items [1] or [2].

[0037] [1].Additional embodiment 1 of the filtration tube of the molten metal filtration unit An additional example of a molten metal filtration unit includes a filtration tube identified as follows: A molten metal filtration unit, comprising: The filter includes a plurality of cylindrical ceramic filter tubes arranged substantially in parallel, each having a substantially circular cross section perpendicular to the longitudinal direction on its outer surface and inner surface, and a pair of side plates disposed at both ends in the longitudinal direction of the plurality of ceramic filter tubes, The plurality of ceramic filter tubes have a first end on a side from which the molten metal is dispensed and a second end on the other side, At least a portion of the plurality of ceramic filtration tubes are When the longitudinal length of the part of the outer surface of the filter tube exposed to the molten metal is L1, the outer diameter of the filter tube is D1, the longitudinal length of the part of the inner surface of the filter tube exposed to the molten metal is L2, and the inner diameter of the filter tube is D2, the following two relational expressions are satisfied: (1) L1 / D1≧8.5 (2) L2 / D2≦21 A molten metal filtration unit that meets all of the above requirements.

[0038] The molten metal filtration unit according to this additional embodiment may further include the following non-limiting features. (i) At least a portion of the plurality of ceramic filtration tubes have an inner diameter at the first end that is greater than the inner diameter at the second end. (ii) In at least some of the plurality of ceramic filtration tubes, the inner diameter at the first end is not less than 100.5% and not more than 120% of the inner diameter at the second end. (iii) In at least a portion of the plurality of ceramic filter tubes, the opening shape of the first end includes, when viewed in the longitudinal direction, the opening shape of the filter tube-mounted end of a substantially circular through hole provided in the side plate on the hot water outlet side of the pair of side plates. (iv) In the above (iii), the inside diameter of the end of the through hole in the side plate on the molten metal discharge side is smaller than the inside diameter of the end of the through hole on the molten metal discharge side. (v) In the above (iv), the inside diameter of the end of the through hole in the side plate on the discharge side is 80% to 99.5% of the inside diameter of the end of the side where the filtration tube is disposed. (vi) At least some of the plurality of ceramic filter tubes are fixed at their respective longitudinal ends by being fitted into recesses formed in the side plates via packings having a shape that fits into the recesses. (vii) At least a portion of the ceramic filtration tubes is formed from a porous material having a porosity of 25% or more and 50% or less.

[0039] [2].Additional embodiment 2 of the filtration tube of the molten metal filtration unit An additional example of a molten metal filtration unit includes a filtration tube identified as follows: A molten metal filtration unit, comprising: The filter includes a plurality of cylindrical ceramic filter tubes arranged substantially in parallel, each having a substantially circular cross section perpendicular to the longitudinal direction on its outer surface and inner surface, and a pair of side plates disposed at both ends in the longitudinal direction of the plurality of ceramic filter tubes, The plurality of ceramic filter tubes have a first end on a side from which the molten metal is dispensed and a second end on the other side, At least a portion of the plurality of ceramic filtration tubes are When the longitudinal length of the part of the outer surface of the filter tube exposed to the molten metal is L1, the outer diameter of the filter tube is D1, the longitudinal length of the part of the inner surface of the filter tube exposed to the molten metal is L2, and the inner diameter of the filter tube is D2, the following two relational expressions are satisfied: (1) L1 / D1≧8.5 (2) L2 / D2 ≧ 22 A molten metal filtration unit that meets all of the above requirements.

[0040] The molten metal filtration unit according to this additional embodiment may further include the following non-limiting features. (i) At least a portion of the plurality of ceramic filtration tubes have an inner diameter at the first end that is greater than the inner diameter at the second end. (ii) In the above (i), in at least some of the plurality of ceramic filtration tubes, the inner diameter at the first end is not less than 100.5% and not more than 150% of the inner diameter at the second end. (iii) In at least a portion of the plurality of ceramic filter tubes, the opening shape of the first end includes, when viewed in the longitudinal direction, the opening shape of the filter tube-mounted end of a substantially circular through hole provided in the side plate on the hot water outlet side of the pair of side plates. (iv) In the above (iii), the inside diameter of the end of the through hole in the side plate on the molten metal discharge side is smaller than the inside diameter of the end of the through hole on the molten metal discharge side. (v) In the above (iv), the inside diameter of the end of the through hole in the side plate on the discharge side is 70% or more and 99.5% or less of the inside diameter of the end of the side where the filtration tube is disposed. (vi) At least some of the plurality of ceramic filter tubes are fixed at their respective longitudinal ends by being fitted into recesses formed in the side plates via packings having a shape that fits into the recesses. (vii) At least a portion of the ceramic filtration tubes is formed from a porous material having a porosity of 25% or more and 50% or less.

[0041] <Additional embodiment regarding the structure of the side plate> The structure of the pair of side plates of the molten metal filtration unit according to the present invention is not particularly limited except as defined in the appended claims. These two side plates may have substantially the same outer shape, that is, a substantially rectangular parallelepiped plate shape, and may also satisfy a specific relationship regarding the inventive shape or dimensions as exemplified in the following items [1] or [2].

[0042] [1].Additional embodiment 1 of the side plate of the molten metal filtration unit An additional example of a molten metal filtration unit includes a pair of side plates identified as follows: A pair of side panels a substantially cylindrical filtration tube connected substantially perpendicularly to the pair of side plates; A molten metal filtration unit comprising: The pair of side plates are a first side plate having a through hole at a portion connected to the filtration tube; a second side plate having a portion connected to the filtration tube closed; When the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, At least one of the pair of side plates has a bottom portion formed such that either one of a left side bottom edge or a right side bottom edge is positioned vertically higher than the other bottom edge. The molten metal filtration unit.

[0043] The molten metal filtration unit according to this additional embodiment may further include the following non-limiting features. (i) When the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, the first side plate has a bottom portion formed such that one of a left side bottom edge and a right side bottom edge is positioned vertically higher than the other bottom edge, When the first side plate has a bottom portion formed such that the left side bottom edge is positioned vertically higher than the right side bottom edge, the second side plate has a bottom portion formed such that the left side bottom edge is positioned vertically higher than the right side bottom edge, or When the first side panel has a bottom portion formed so that the right side bottom edge is positioned vertically higher than the left side bottom edge, the second side panel has a bottom portion formed so that the right side bottom edge is positioned vertically higher than the left side bottom edge. (ii) When the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, At least one of the pair of side plates has a step portion formed so that either the left side base or the right side base is positioned vertically higher than the other base. (iii) In the above (ii), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The pair of side plates have a step portion formed so that the left side base is positioned vertically higher than the right side base. (iv) In the above (ii), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, the step portion includes a first bottom portion which is the lowest portion and a second bottom portion which is formed so as to be positioned vertically higher than the first bottom portion, The ratio (W1 / W2) of the horizontal length W1 of the first bottom to the horizontal length W2 of the second bottom is 0.1 or more and 6.0 or less, where W1 and W2 are lengths parallel to the longitudinal direction of the filtration tube. (v) In the above (ii), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, the step portion includes a first bottom portion which is the lowest portion and a second bottom portion which is formed so as to be positioned vertically higher than the first bottom portion, The ratio (W1 / H2) of the horizontal length W1 of the first bottom to the vertical length H2 from the first bottom to the second bottom is 0.1 or more and 11 or less, where W1 is the length in a direction parallel to the longitudinal direction of the filtration tube. (vi) When the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, At least one of the pair of side panels is formed so that either the left or right base edge is positioned vertically higher than the other base edge, and is provided with a bottom having a first bottom edge which is the lowest part, and a sloping portion connecting the first bottom edge to the base edge which is positioned vertically higher. (vii) In the above (vi), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The ratio (W1' / W2') of the horizontal length W1' of the first bottom portion to the horizontal length W2' of the inclined portion is 0 or more and 6.0 or less, where W1' and W2' are lengths parallel to the longitudinal direction of the filtration tube. (viii) In the above (vi), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The ratio (W1' / H2') of the horizontal length W1' of the first bottom to the vertical length H2' from the end of the inclined portion that contacts the first bottom to the other end of the inclined portion is greater than or equal to 0 and less than 320, where W1' is the length in a direction parallel to the longitudinal direction of the filtration tube. (ix) In the above (viii), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The angle θ1 between the inclined portion and the vertical direction is equal to or greater than 60° and equal to or less than 89°. (x) In the above (vi), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The pair of side plates are formed so that the left side base is positioned vertically higher than the right side base, and each side has a bottom having a first bottom portion which is the lowest portion and a sloping portion connecting the first bottom portion to the left side base. (xi) In the above (vi), when the longitudinal direction of the filtration tube is approximately horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, The pair of side plates are formed so that the right side base is positioned vertically higher than the left side base, and each have a bottom having a first bottom portion which is the lowest part, and a sloping portion connecting the first bottom portion to the right side base. (xii) A molten metal filtering device having a molten metal outlet, The molten metal filtration unit according to the above (ix), in which the pair of side plates are provided with an inclined portion formed such that, when the longitudinal direction of the filtration tube is substantially horizontal, the first side plate is located on the left side of the filtration tube, and the second side plate is located on the right side of the filtration tube, the right side base is positioned higher in the vertical direction than the left side base, is disposed so that the first side plate is in contact with the tapping port, The filtration device is provided with a wedge-shaped protrusion having an angle θ2 between a surface in contact with the molten metal filtration unit and a horizontal plane on the hearth, and the sum of θ1 and θ2 is 61° or more and 114° or less. The filtration device.

[0044] [2].Additional embodiment 2 of the molten metal filtration unit An additional example of a molten metal filtration unit includes a pair of side plates identified as follows: A pair of side panels; a substantially cylindrical filtration tube connected substantially perpendicularly to each of the pair of side plates; A molten metal filtration unit comprising: The pair of side plates are a first side plate having a through hole at a portion connected to the filtration tube; a second side plate having a portion connected to the filtration tube closed; Each side panel has at least one leg depending from a bottom surface of the side panel; When the longitudinal direction of the filtration tube is substantially horizontal, the lowest position of the leg portion of the second side plate in the vertical direction is lower than the lowest position of the leg portion of the first side plate in the vertical direction. The molten metal filtration unit.

[0045] The molten metal filtration unit according to this additional embodiment may further include the following non-limiting features. (i) When the longitudinal direction of the filtration tube is approximately horizontal, the ratio of the vertical length of the leg of the first side plate to the vertical length of the leg of the second side plate is not less than 0.20 and less than 1.0. (ii) The total ground contact area of ​​all the legs in the molten metal filtration unit is 0.015 or more and 0.075 or less relative to the total bottom area of ​​the pair of side plates. (iii) In the above (ii), the total ground contact area of ​​all the legs in the molten metal filtration unit is 0.020 or more and 0.060 or less relative to the total bottom area of ​​the pair of side plates. (iv) At least, the first side panel has two legs and the second side panel has one leg. (v) In the above (iv), at least two legs are provided near both longitudinal ends of the bottom surface of the first side plate, and one leg is provided approximately at the longitudinal center of the bottom surface of the second side plate. EXAMPLES

[0046] The embodiments of the present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0047] Filtration units of Examples 1 to 5 and Comparative Examples 1 to 5 were produced with the dimensions and the number of legs and filtration tubes shown in Table 1. The overall length of the filtration unit differs depending on the length of the filtration tubes constituting the filtration unit, and the overall length L of the filtration unit corresponds to L in Fig. 2, and the side plate width W corresponds to W in Fig. 3 or 4. In Examples 1 to 5, the first side plate had two legs, and the second side plate had one leg. In Comparative Examples 1 to 5, the first side plate had two legs, and the second side plate had two legs. The filtration device has a filtration chamber volume of 1.39 m 3 The filter had a base that corresponded to the number of legs of the filter unit to be installed on the hearth of the filter chamber. The filter was made of refractory material in which SiC aggregate was bonded with Si3N4.

[0048] Molten metal filtering using a filtering unit The filtration units of Examples 1 to 5 and Comparative Examples 1 to 5 were used to filter the molten metal, with the following steps (a) to (e) being considered as one filtering operation. (a) Installation of a filtration unit The filtration unit was placed in the filtration chamber so that the legs of the filtration unit rested on the base in the filtration chamber. The filtration unit was pressed using a pressing jack so that the first side plate of the filtration unit was in close contact with the wall surface of the tap hole side. The filtration unit was fixed by driving a wedge between the second side plate and the wall surface of the filtration device. (b) Preheating the filtration device The filtration device was heated at 80° C. / hour using a temperature-controlled heater installed in the filtration chamber. After the controlled temperature of the temperature-controlled heater reached 800° C., heating by the temperature-controlled heater was continued so as to maintain the controlled temperature at 800° C. Heating by the temperature-controlled heater was continued until the temperature sensor installed in the lowest filtration tube in the filtration unit reached 700° C. (c) Filtration of molten metal 1,000 tons of molten metal at 680℃ to 750℃ was poured into a filtering device and filtered over a period of 14 days. (d) Cooling down of the filtration device The filtration device was left standing until the temperature sensor provided in the lowest filtration tube in the filtration unit reached room temperature. (e) Removal of the filtration unit The wedge between the second side plate and the wall of the filtration apparatus was removed and the filtration unit was removed from the filtration apparatus.

[0049] Evaluation of the placement stability of filtration units The placement stability of the filtration unit was evaluated by inserting a gap gauge between the legs of the filtration unit and the base. After step (a) of the above filtration work and before step (b), a gap gauge was inserted between each leg and the base of the filtration chamber. The placement stability of the filtration unit was evaluated as follows based on the value of the gap gauge inserted into the largest gap between each leg and the base of the filtration chamber. A: Less than 0.5mm (a 0.5mm gap gauge could not be inserted into any of the legs). B: 0.5mm or more but less than 2.0mm (a 0.5mm gap gauge can be inserted into one or more legs, but a 2.0mm gap gauge cannot be inserted). C: 2.0mm or more (one or more legs have a 2.0mm gap gauge).

[0050] The placement stability of the filtration unit was evaluated after the filtration unit was installed in the filtration chamber for the first time (i.e., after step (a) of the first filtration operation), after the 15th filtration operation (i.e., after step (a) of the 16th filtration operation), and after the 30th filtration operation (i.e., after step (a) of the 31st filtration operation).

[0051] Evaluating preheating of filtration equipment The preheating ability of the filtration device was evaluated by measuring the change in temperature over time of the filtration unit in step (b) of the first filtration operation in order to eliminate the influence of deterioration of the filtration device over time. Specifically, the time until the temperature sensor provided in the lowest filtration tube of the filtration unit reached 500°C was measured in step (b) of the first filtration operation. The change in temperature over time controlled by the temperature control heater and the change in temperature over time of the filtration units of Example 1 and Comparative Example 1 are shown in FIG. 5. The preheating ability of the filtration device was evaluated based on the change in temperature over time for the filtration units of Examples 1 to 5 and Comparative Examples 1 to 5 as follows. A: The time to reach 500°C was less than 80 hours. B: The time required to reach 500°C was 80 hours or more and less than 85 hours. C: The time required to reach 500°C was 85 hours or more.

[0052] The dimensions of the filtration unit and the evaluation results are shown in Table 1. [Table 1] [Industrial Applicability]

[0053] According to the filtration unit of the present invention, by optimizing the relationship between the numbers of legs provided on the two side plates, it is possible to stably arrange the filtration chamber, which has deteriorated with age, and to improve the preheating efficiency of the filtration device. Therefore, the filtration unit of the present invention can facilitate preparation for filtration of molten metal, and thus improves the efficiency of filtering impurities from molten metal such as aluminum, and is therefore applicable to various industries requiring such filtering, such as the metal industry and the steel industry. [Explanation of symbols]

[0054] 101:Filtration device 102: Entrance 103:Filtration chamber 104: Filtration unit 105:Tap Room 106, 110: Tap hole 107:First side plate 108:Second side plate 109: Filtration tube 201: Leg of first side panel 202: Leg of second side panel

Claims

1. A pair of side panels; a substantially cylindrical filtration tube connected substantially perpendicularly to each of the pair of side plates; A molten metal filtration unit comprising: The pair of side plates are a first side plate having a through hole at a portion connected to the filtration tube; a second side plate having a portion connected to the filtration tube closed; Each side panel has a leg extending downward from the bottom surface of the side panel, The number of legs provided on the first side panel is at least one more than the number of legs provided on the second side panel; When the molten metal filtration unit is placed on a horizontal surface and observed from above, the area of ​​the molten metal filtration unit is represented by the product of the length of the molten metal filtration unit in the longitudinal direction of the filtration tube and the longitudinal length of the side plate, and is defined as S1. The total area of ​​the ground contact areas of all the legs of the molten metal filtration unit is S2, The area ratio S2 / S1 is 0.0020 or more and 0.015 or less. The molten metal filtration unit.

2. The first side panel has two legs and the second side panel has one leg. The molten metal filtration unit according to claim 1.

3. The first side plate has two legs near both ends of a bottom surface of the first side plate in a longitudinal direction, and the second side plate has one leg at a substantially central portion of a bottom surface of the second side plate in a longitudinal direction. The molten metal filtration unit according to claim 1.