TW446570B - Molten metal filtration - Google Patents

Abstract

Molten metal is filtered using a filter (10, 28, 44) comprising a porous carbon foam substrate coated substantially throughout with a refractory metal or refractory compound formed by chemical vapour deposition, and having a filtration porosity of less than 90%, and preferably at least 75%, and a ligament solid fraction of at least 0.95, using apparatus comprising a holding vessel (1, 21, 40) having an inlet (2, 41) and an outlet (3, 22, 42) for the molten metal, at least one filter housing, the or each housing containing a filter (10, 28, 44), means for holding and sealing the filter or filters (10, 28, 44) in place, and means (5, 38) for preheating the holding vessel (1, 21, 40) and the filter or filters (10, 28, 44) prior to using the apparatus for filtering molten metal.

Description

Printed by the Consumers' Cooperative of the Central Bureau of Health of the Ministry of Economic Affairs 44657 0 Α7 Β7 V. Description of the invention (/) The invention relates to the filtration of molten metal, especially the filtration of molten aluminum metal and molten aluminum alloy. The present invention will make special reference to the above metals It is explained that β molten metal, especially aluminum metal, has been filtered by many different filtering devices for many years, and now in the aluminum metal industry, molten aluminum metal and molten aluminum alloy are generally filtered before casting. Although there have been many types of filters in the past, the most common users today are ceramic foam materials * which are impregnated by a polyurethane foam material with a slurry vessel containing a refractory material and a binder and then dried by the impregnated foam material * In addition, the filter with adhesive particle material is made of a mixture of refractory material and a sticky residue, and the mixture is extruded to form a desired shape * and the shape is heated. Ceramic foam filters and their use in molten metal filtration are disclosed in several main patent cases, such as 3090094, 38939Π, 3947363, 4024056, 5190897, and 5520823 • US Patent 15 Case 4024056 discloses a slantable surface In addition to the application of ceramsite foam material filter plate, the plate has a hole size of about 2-18 holes per centimeter straight line or about 5-45 holes (5-45ppi) per inch straight line. This type of filter is widely used in fused aluminum In the filtration of metals "US Patent No. 3524548 discloses a rigid 20-hole filter media used in aluminum metal, which is made by combining refractory particles with a glass material resistant to molten aluminum and gold flexion" Made into a plate or camp and used. U.S. Pat. No. 3747765 discloses a rigid filter tube for filtering molten metal, which is made by combining a similar refractory particle admixture with a pre-fused glass binder. 25 U.S. Pat. No. 4,964,993 in a molten metal filter Contains the paper size of China® CNS iM specification (210X297 mm) [Read the precautions on the back before filling in this page]-* 4465 7 0 The Central Bureau of Standards, Ministry of Economic Affairs A7 B7 5. Description of the invention (>) At least one cylindrical end encloses the porous ceramic filter element, which is connected to a substantially horizontal porous ceramic sealing plate filter element in a vertical orientation. The vertical filter element may be made of bonded particulate refractory material * or it may be in the form of a ceramic foam material. Β 5 ceramic foam material filters have been successfully used commercially for many years because they are Synthetic particulate filters are easier to use, less costly, and have a smaller unit footprint. However, its pore size is larger than that of a bonded particulate filter, so its filtration efficiency is lower. Ceramic foam filters are widely used with a thickness of about 24 holes per cm or 10 (60 PPi) per inch. However, it becomes more difficult to manufacture as the cell size decreases, as it becomes more difficult to impregnate the finer cell size polyurethane foam with the refractory slurry «. Increasing the number of blocked pores reduces the porosity available for filtration. This results in a decrease in the flow rate per unit surface area, which can cause usage problems during injection or reduce filtration capacity. 15 Bonded particulate filters provide several advantages over ceramic foam when used as a filter for aluminum alloys. It generally has higher strength and higher density, and because of its lower porosity, it has a more tortuous flow channel and does not contain blocked pores. It provides the ability to remove oxides and other inclusions from aluminum metal. A larger filtration efficiency. 20 However, the high density and low porosity (typically 30-4596) of bonded particulate filters can be disadvantageous and limit their commercial use. Because the bonded particulate filter is denser than the ceramic foam material, it obviously requires more preheating to achieve the filter's full filling at the beginning of the filtration and optimize the filtering performance, and to quickly and uniformly meet its requirements Preheating is quite difficult and difficult. Some bonded particulate filters also have their own pre-heating requirements

This paper size is suitable for Chinese B homes (CNS) A4 washing grid (2 丨 0X297mm J (please read the precautions on the back before filling in this page) Line 446570 Printed by the Cooper Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Β7 V. Description of the invention (>) Other disadvantages. For example, when it is used in the form of a flat plate in the filtering equipment of an aluminum metal foundry, the plate must be preheated to allow molten aluminum metal to flow through the plate without solidifying. This kind of preheating of the plate is usually achieved by direct flame contact on the bottom surface of the plate. Due to the extremely poor shock resistance of some bonded particle filter plates, the filter plate will be peeled off. The high density of the filter also makes changing the bonded particulate filter element a very labor-intensive operation. The low porosity not only limits the flow rate per unit surface area, but also increases the velocity of the gap metal in the pores of the bonded particulate filter. To overcome The problem of this limited flow rate necessitates the use of 10 types of bonded particulate filter systems with a very large surface area. This is generally done using several bundles of long tubes, which requires the use of a A box or container that remains "In Japanese Patent Application Publication No. 1-141884, it has been proposed that a carbon foam substrate is used as a filter for molten metal, and the substrate is coated with silicon carbide by a chemical vapor deposition method. The applied material has a porosity of 90 to 99%, and the application states that if the porosity is less than 90X when filtering molten aluminum metal, the blockage of pores and the loss of aluminum metal will be extremely large. Above 99X, the efficiency of removing impurities will be poor and the strength of the foam material will be insufficient. 20 Compared to the content taught in B Patent Application Publication No. Bu 141884, today it has been found that molten metal, especially molten A preferred converter for aluminum metal can be manufactured by depositing a refractory metal or a refractory compound on a carbon foam substrate based on chemical vapor deposition, as long as the filter has a filtration porosity of less than 90 ¾ And has a tie rate of at least 0.925. The paper size is applicable to the national standard (CNS) M specifications (210X297 mm) (please read the precautions on the back of 1 * before filling this page) ^ Order! 446570 A7 B7 Du printed by the Central Bureau of Standards of the Ministry of Economic Affairs and Consumer Cooperation. 5. Description of the Invention (Jiang) Herein, a method for filtering molten metal is proposed according to the present invention. The method includes providing a filter that includes a method of splashing by chemical vapor. The product method is substantially completely coated with a porous carbon foam material matrix of a refractory metal or a refractory compound. The filter has a filtration porosity of less than 5 90¾ as defined below, and has a banded solid rate of at least 0.95 as defined below. And cause molten metal to flow through the filter to remove inclusions contained in the molten metal. In the context of the present invention, a ligament is defined as a substantially solid interconnecting pillar that forms the structure of a foam material . 10 Fi 1 trat ion porosi ty is defined as the percentage of the total volume of a foam filter body outside the band that can be used to filter molten metal in the open interactive connection space · void fraction The total volume of the empty space in a foam filter is divided by the volume occupied by the foam filter, and the empty space in a foam filter is any non-solid volume. For example, for a foam material filter with a size of 100 mm X 100 mm X 100 mm and containing 850,000 cubic meters of vacant space «, its empty body rate is 850,000 Λ100χ ΙΟχχ 100) or 0.85 · 20 Void ratio can be expressed as follows: Void ratio = 1 ~ foaming material filter "Density foam material with nylon density. For example, a mass of 420 grams of 100 mm X 100 mm X 100 The density of the millimeter foam filter 艎 is 0.42 g / 25 cubic centimeters. If the foam material is an aluminum foam material, its lace theory (please read the precautions on the back before filling this page)

-I This paper is in Chinese national standard ^ | t (CNS) A4¾ grid (210X297mm) ί 446570 Α7 Β7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of invention (ί) Density is 2.8 grams / Cubic centimeter, so its empty body ratio is 10. 42/2. 8) or 0.85 »Lace solid rate is defined as the volume of solid material constituting the lace divided by the volume occupied by the lace. 5 For example, a 100mm X 100mm X 100mm filter with a strap volume of 150,000 cubic millimeters and a strap solid volume of 75,000 cubic meters has a tie rate of 0.50. Preferably, the filter used in the method of the present invention has a filtration porosity of at least 75 °, more preferably at least 80X. 10 The carbon foam material is preferably a reticulated carbon foam material, and the porous carbon-based vessel may be composed of a porous organic matrix. For example, a polyurethane foam is pyrolyzed, and if necessary, the polyurethane foam may first be impregnated with a resin or a similar organic material. European Patent Application Publication No. 747124A discloses a suitable method for producing a carbon foam material, in which a polyurethane foam material is impregnated with a resin, and the resin impregnated foam material is pyrolyzed at a temperature of 600 to 120 (TC temperature to Polyurethanes and resins are converted to carbon. The chemical vapour depositon method used in this article — the term includes chemical vapor deposition and chemical vapor infiltration. 20 In the chemical vapor deposition method, solid-phase refractory materials are introduced from the gas phase. Aggregation and growth of materials, for example, a silicon carbide coating may be deposited on a porous carbon-based substrate by decomposition of trichlorosilane. The chemical vapor deposition may be performed by any conventional technique, and chemically A suitable method for coating carbon-based rhenium by the vapor deposition method is disclosed in U.S. Patent Nos. 5,154,970, 5,283,109, 5,372,380, 25 and European Patent Application Publication No. 747,124. T. This paper is sized to the standards of CNS > A4 (210X297mm) (Please read the precautions on the back before filling this page)

• —I— I 446570 Yin Ben A7 B7, Consumers Cooperative of Central Standards Bureau, Ministry of Economic Affairs 5. Description of the invention ") The chemical vapor deposition method must be applied to the porous carbon substrate to form a filter refractory metal or refractory compound. It can coexist with the molten metal to be filtered, that is, it must resist the molten metal, and it must not contaminate the molten metal. It can be applied to the porous carbon substrate 5 by a chemical vapor deposition method to form a transition device for the method of the present invention. The yttrium metal and yttrium are suitable for fire metal. Suitable fire retardant compounds include silicon carbide, silicon argon, hafnium carbide, zirconium nitride, hafnium boride, niobium carbide, niobium halide, niobium boride, titanium carbide, titanium nitride. , Titanium boride, hafnium carbide, hafnium nitride, and hafnium boride • The preferred coating material is silicon carbide because of its proper physical properties such as smaller density and a high thermal conductivity, and makes the method of the present invention The filters used can be manufactured economically. Specifically, when the method of the present invention is implemented using a reticulated carbon foam material that has been coated with a refractory metal or metal compound by a chemical vapor deposition method, This filter has several advantages over conventional ceramic foam filters made from an organic foam material 15 impregnated with a particulate refractory slurry Λ. The deposited amount of the coated refractory metal or metal compound is preferably the smallest. 0.25g / cm3. The strength of individual straps and filter bodies depends on the solid weight of Tu Wei's material in the system. Chemical vapor shock 20 The essence of fine method makes the carbon foam material «coating The density may be slightly different, and if the density of the intermediate coating is expected to be less than 0.25 g / cm3, the difference in neodymium may cause the filter to not have sufficient resistance to cooking to withstand the industrial environment. Or refractory compounds may break during processing, and if a filter skeleton does not have sufficient strength, this paper size can be applied to China National Sample (CNS > A4 specification (2 丨 0X297 mm) (Please read the back (Please note this page and fill in this page again) * τ 446 57 0 The Ministry of Economic Affairs of the China Standards and Standards Bureau, Consumers Cooperative, Ajia B7 B7 V. Description of the Invention (9) Can be broken in processing. Filters that filter molten aluminum for more than a week require a minimum crush strength of 35 kg / cm² (500 psi), and the filter used in the method of the present invention meets this requirement. 5 As far as production conditions are concerned, An important characteristic of the filter used in the method of the present invention is that essentially all the void fractions of the filter are available for molten metal flow, and the void fraction is as defined by the previously used filtration porosity. It is a constant pore size In terms of surface area, the higher the porosity, the higher the molten metal flow rate or the lower the cell speed. A lower cell speed10 is accompanied by a larger molten metal content capture performance, thus improving the overall filtration efficiency. The higher porosity of the filter also results in a larger storage volume for trapped inclusions, which means that a single filter will not be able to filter larger metals before they become clogged and need to be replaced. Its known ceramic foam material The filter becomes a contrast. The conventional 15 filter has many voids in the content of the hollow t center of the strap, and becomes the microporosity of the strap itself. Partly because molten metal flow cannot be used because high pressure will be required to force molten metal into such micro-tubes, so it is not included in the filtration porosity. In addition, many empty lines change due to the blocking area formed in the ceramic foam material. It cannot be used for molten 20 metal flow. This further reduces the fantasy ratio compared to the filtration porosity. Figures 1 and 2 at the back show a comparison of a conventional ceramic foam filter with a chemical vapor deposited refractory metal or refractory compound-coated carbon foam filter used in the method of the present invention. 25 囷 1 is a simplified cross-sectional view of a conventional ceramic foam filter. This paper size is applicable to China National Standard Car (CNS) A4 specifications (2 丨 〇 > < 297 mm) (Please read the note on the back first Please fill in this page again)--,? Τ 4465 7 0 A7 B7 V. Description of the invention (?) The transition device is made of a polyurethane foam impregnated with a ceramic slurry and fired and melted the foam material. The filter has a Hollow lacing core (A) and a ceramic lacing (β) β ring with a solid content of 0.50 are available. The schematic diagram of the filter lacing load surface used in the method of the present invention. The vapor deposition method is made by coating a carbon foam substrate with a refractory metal or a refractory compound. The filter has a solid carbon lace core (C) and a substantially no-laundry refractory metal or refractory compound (d) lace coating. The minimum true hip ratio of the coating is 0.95 »within the lace In addition to reducing the filtration porosity, the voids also reduce the strength of the ceramic 10 ceramic foam 洙 material filter 醴. For boats to be used in an industrial filtration process, a filter must be strong enough and durable enough to withstand handling, installation, and use. On the other hand, for the filter to function effectively as a filter, it must have a sufficiently high filtration porosity to provide low pressure drop and an industrial flow rate with a minimum filtration of 15 system traces. When the parameters are the same, the higher the cross section rate of the filter vessel, the lower the strength. In the filter used in the method of the present invention, when the filter porosity is added at a 100 dimensional void rate, the filter is filtered for a given empty rate. The strength of the device will reach its maximum value. Printed by the Central Laboratories of the Ministry of Economic Affairs of the Bayer Consumer Cooperative (please read the precautions on the back before filling this page). Line 20 For example, a silicon carbide filter used in the method of the present invention A carbon foam material with a nominally 3% volume solid or 97¾ filtration porosity and essentially void-free carbon lacing is coated with a uniformly distributed, essentially seatless, aged SiC coating to a thickness of 0.32 g / cubic The smallest amount in centimeters. One of the non-voided solid volumes of chemical vapor liquefied silicon carbide has a density of 3.2 grams per cubic centimeter, and a paper size of 0.32 grams per cubic centimeter applies to the Chinese national kneading rate (CNS > A4 specifications < 2 丨 0 > < 297 mm) 446570 Α7 Β7 V. Description of the invention (^) The silicon carbide coating with a centimeter is a solid silicon carbide with a volume of 10%. The total volume percentage of the entity is 3¾ carbon and 10% silicon carbide. The filter body has a hollow body ratio of 0.87. All hollow body ratios are available for molten metal. The filter porosity of the filter is 87¾. 5 There is no adhesive in the filter, no sintering aids (because there is no need to fire or sinter the filter after the filter is generated), and there are no impurities. Therefore, the filter has improved corrosion resistance in contact with molten metal, and has a large strength-to-weight ratio. Compared with a conventional ceramic foam filter, the filter has a stronger strength and a lower density of 10 degrees. Because the filter has a lower density, it is easier to preheat. Due to the above advantages, when the method of the present invention is used, a filtration system having a higher filtration efficiency and a longer service life than a system containing a ceramic foam filter or a particulate filter can be used. The filter used in the method of the invention may be in the form of a flat plate, but preferably it is in the form of a tube. In the aluminum industry, plural tubes are generally called Yixinzi. Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page). Although it is customary to use a flat plate to filter molten aluminum metal, it has disadvantages because in order to provide sufficient filter surface area to enable Da Dong's molten aluminum metal to be processed at an acceptable production rate, it is necessary to make the filter plate very large and internally The furnace or container to be filtered must also be large to fit the filter plate. Therefore, it is necessary to use a filter whose shape provides a large surface area, and it requires less fitting space. Therefore, a tubular or cardiac filter is more advantageous in the above considerations. Tubular or cored filters made from conventional ceramic foam materials have very little commercial use because they are difficult to manufacture, have low strength, have 25 blocked holes, are difficult to preheat, and are difficult to wet molten metal. Only applicable to 11 This paper standard is applicable to China National Standards (CNS) 8 4 specifications Y21OX297 (publication) 446570 A7 B7 printed by the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (f ts) In contact with molten metal For a short period of time. Therefore, tubular or core filters commercially used in the aluminum industry are usually bonded particulate to fire filters. A carbon foam material coated by a chemical vapor deposition method with a refractory metal or a refractory compound and having a filtration porosity of less than 9096 and a solid rate of at least 0.95 is not affected by the above disadvantages, which is why it is particularly suitable for tubular or Reasons for applying the method of the present invention. The method of filtering molten metal may be applied, for example, in a filtering device including the following components: a container having an inlet and an outlet for the use of the molten metal 10; at least one external wave transformer, each ... 95 The foreign army accommodates a filter that includes a porous carbon foam material base that is substantially completely coated with a refractory metal or refractory material by a chemical vapor deposition method, and the base has a filtering porosity of less than 90¾ and at least 0.95. The means for securing the belt; the device for supporting and sealing the filter in place; and the device for preheating the container and the filter before filtering the molten metal using the device. Therefore, according to a further feature of the present invention * here is provided a device for filtering molten metal as described above. The filter used in the above device may be a filter plate, but in a preferred embodiment, a filter tube is used, and the filter The filter is preferably a tubular filter element disposed substantially horizontally. The nuclear sealing device should be able to seal the filter in position to ensure that all molten metal passes through the filter without applying excessive force to the filter, and the configuration of the cover and sealing device used should preferably make the filter easily accessible. Install and remove. The heating device may be, for example, one or more gas. The paper size is applicable to the Chinese «house standard rate (CNS) A4 size (210X297 mm) (please read the precautions on the back before filling this page).

(Subniftted on MSchJ ^ ioil)

Enel.⑴ 10 burner or electric heater, which may be located in a lid on top of the container. The position of the filter in the containment container with respect to the inlet is important, so that when the containment container is filled with molten metal through the inlet, 'the surface of the molten metal in the containment container exceeds the height of the filter enough to fill the filter, That is, starting to flow molten metal through the filter. Since the inner surface of the container must bear molten metal such as aluminum and should not contaminate the metal, the container should be made of a refractory material or lined with a pair of refractory materials. The refractory material should meet the above requirements. To reduce the heat loss through the wall of the containment container, a refractory insulation liner may be installed between the containment container shell and the refractory liner. It is also possible to line the cover with a thermal insulation material to reduce heat loss. An example of a suitable refractory material constituting the inner contacting metal surface of the container is a fused silica stone castable material having a density of about 1.8 g / cm3. An example of the thermal insulation material of the container wall and the lid is a refractory castable material made of ceramic fibers with a density of less than 1.4 g / cm3 and also containing materials in the form of blocks or blankets or modules. Schematic description Please read the precautions of Si before filling in the page t. Printed by the Ministry of Economic Affairs, Intellectual Property Bureau, Employees' Cooperatives 25 The present invention is described with reference to the accompanying drawings 3 to 7, which are as follows: A schematic cross-sectional view of a conventional ceramic foam material filter; FIG. 2 is a schematic view of a load carrying device used in the method of the present invention; FIG. 3 is a molten metal filtering device having a plurality of filter tubes according to the present invention Horizontal section view; Figure 4 is a vertical section view through the equipment of Figure 3; 13 This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm *)

V. Description of the Invention () Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, Figure 5 and Figure 3, a detailed diagram of the molten metal filter equipment, showing how the filter tube is positioned in the device and supported in position; Figure 6 is A vertical cross-sectional view of another embodiment of a molten metal filtering device according to the present invention; and FIG. 7 is a vertical sectional view of another embodiment of the molten metal filtering device according to the present invention. DETAILED DESCRIPTION Referring now to Figures 3 to 5, a device for filtering molten metal includes a pair of 10 fire-lined containers, a molten metal inlet 2, a molten metal outlet 3, and a refractory lining cover 4 '. The cover has heating means 5 therein. The inside of the container 1 is divided into an inlet chamber 6 and an outlet chamber 7 by a refractory partition 8 which extends across the container 1 and approaches the top of the container, and has a hole 9 connecting the inlet chamber 6 and the outlet chamber 7. A group of eleven filter tubes are positioned near the base of 15 containers 1 so that the filter tubes 10 are arranged in three rows stacked upward. The filter tubes are in the form of pyrolytic reticulated carbon foam material and have been coated by chemical vapor deposition. Cloth silicon carbide 'and has a filtration porosity of 87% and a solid rate of 0.995. One end of each passing tube 10 is inserted into a notch of a pair of fire plates 11, and the other end of each filter tube is positioned in one of a refractory plate 12. 20 The perforated notch makes the hole in the notch and the partition 8 The inner hole 9 is aligned. The filter tube 10 is supported and sealed in position by applying a support device 13 without applying excessive force to the filter tube 10. The support device is installed above the filter tube 10 near the end of the tube adjacent to the 8 hole 9 of the partition plate. The filter tube is in the container. The position inside 1 makes the height of the top of the container 1 above the top row of filter tubes 10 high enough to allow the filter to be filled when the inlet chamber 6 is filled with molten metal. Before using this equipment to filter the molten metal, the internal standard of container 1 and the paper size are applicable to the national standard (CNS > A4 specification (210 X 297 public love) I ------ l · --I > Install! ^ ---- Order i I ----- (Please read the precautions on the back before filling in this page)

A "6570 Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (丨,) The filter tube 10 is preheated by a heating device 5, which may be a gas burner or an electric heater, for example. In the case of molten aluminum metal filtration, it is necessary for the inner surface of the filter tube 10 to be preheated to at least 600 ° C. The heating device 5 also maintains the temperature of the molten metal on the container 1 · 5 molten metal enters through the inlet 2 during use The inlet chamber 6 is filtered by the filter tube 10, enters the outlet chamber 7 through the hole 9 in the partition plate 8, and is then discharged through the outlet 3. Referring to Fig. 6, a device for filtering molten metal includes a refractory container 21 and a refractory lining cover 23, the container has a molten metal inlet (not shown in the circle) and a molten metal outlet 22. The interior of the container 21 is divided into an outlet chamber 24 and an inlet chamber by a refractory partition 26 25. The partition extends across the container 21 and has a hole 27 connecting the outlet chamber 24 and the inlet chamber 25. The four filter tubes 28 are in the form of pyrolytic reticulated carbon foam material and have been coated with silicon carbide by chemical vapor deposition method And have The filtration porosity of 87¾ and 15 and the strapping efficiency of 0.995 are arranged in a straight line in the inlet chamber 25 near the base of the container 21. One end of each filter tube 28 is inserted into a recess of a pair of fire plates 29 In the mouth, and the opposite end of each filter tube is positioned in a perforated recess of a refractory plate 30 so that the hole in the recess and the hole 27 in the partition plate 26 are aligned with the "filter tube 28 supported by the support device 31 and Sealed in position without exerting excessive force on the filter tube 28, the support device is installed above the filter tube 28 near the end of the tube adjacent to the hole 26 of the fascia 26. The position of the filter tube 28 in the container 21 exceeds the top of the container JI 21 The height of the filter tube 28 is sufficient to allow the filter to be filled when the chamber 25 is filled with molten metal. 25 The refractory lining cover 23 has two holes 32 and 33, respectively. ) M size (2 丨 OX297mm) (Please read the note on the back before filling in this page) Order 'line 4465 7 0 Α7 Β7 V. Description of the invention (k) The inner hole on the top of the container above chambers 24 and 25 34 and 35 and two plugs 36 and 37 are in line. In this device Before use, the plugs 36 and 37 are raised to close the holes 32 and 33 in the cover 23, and the inside of the cover 23 and the container 21 is preheated by the gas burner 38. After the preheating, the plugs 36 and 37 5 are lowered to The holes 34 and 35 in the top of the container are closed. In use, molten metal enters the inlet chamber 25, is filtered through a filter tube 28, passes through the inner hole 27 of the partition plate 26, enters the outlet chamber 24, and is discharged out of the container 21 through the outlet 22. The molten metal in the container 21 is maintained at the desired temperature by an immersion heater 39 located in the inlet chamber 25 and the outlet chamber 24. The following example is also used to illustrate the present invention: Example 1 has been found in practice to be used in A commercial filter base for filtering molten aluminum metal 15 must have a minimum crushing strength greater than 35 kg / cm2 (500 pieces / square inch leaf). A series of experiments were performed to establish the relationship between crush strength and filtration porosity. Printed by the Central Standards Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperatives (Please read the precautions on the back before filling this page) Nominally 9 796 has a porous foam material based on the porosity and has airless chandelier and belts. The chemical vapor deposition method coats several different levels of broken silicon 20 to produce a filter plate with a solid rate of 0.995 and a certain range of filter porosity. For each layer of silicon carbide and for each porosity, several coated plates β were made. A load-bearing surface was cut from each plate and its crushing strength was determined. The actual withdrawal rate of the lacing is calculated by erection and polishing a plate section and then visually inspecting the lacing. 25 The silicon carbide solid volume ratio (%) of each layer of silicon carbide coating. The size of this paper is applicable to China National Standard (CNS) A4 (2 丨 OX297) 漦 4465 7 0 A7 B7 V. Description of the invention ( And the minimum crushing strength are shown in the lower clip. The volume ratio of the silicon carbide cargo body (¾) filtration porosity (") kg 2 — 95 3 94 4 93 5 92 crushing strength (cm²) 90 91 15. 5 -I ---- 21. 1 28ΓΓ 10 W " δΤ ~ 35Γ2 ~ 70 " JT7? ~ 59. 8 (Please read the precautions on the back before filling this page) Example 2 Prepare two 30.5 cm x 30.5 cm x 2.5 cm thick wave 5 plates' One plate has about 26 holes (26ppc) per inch or 65 holes (65ppi) per inch, and the other plate has about 32 holes per cm or 80 holes per inch Both have a filtering porosity of 87X and a solid rate of 0.995. The reticulated polyurethane foam material is pyrolyzed to produce a carbon foam material, and the carbon foam material is processed to the desired size. Then the carbon foam material is 10 A filter is formed by coating silicon carbide by chemical vapor deposition method. A filter is inserted into a 50 cm deep filter Inside, the filter and filter cup were preheated by a gas blow pipe. It was found that due to the high thermal conductivity and low thermal mass of the filter, the filter became hot almost immediately. Then about 3175 kg of fusion 6061 aluminum alloy was poured into the cup and passed the 15 filter. In the test using a filter of 32 holes per cm or 80 holes per inch, the aluminum alloy was added with an additional 5 to 50 micron size. Inscriptions are contaminated * When using 26 holes per centimeter or 65 holes per British order, the Central Bureau of Standards of the Ministry of Economic Affairs, Shellfish Consumer Cooperation Du printed equipment

.III 17: 446570 Yin Ben A7 B7, Shellfish Consumer Cooperative of Central Bureau of Standards, Ministry of Economic Affairs 5. In the case of the device, it takes about 1 hour to make all the molten metal transition, and the corresponding flow rate is about 0_ 05 Kg / min / cm2. In the case of a filter of 32 holes per cm or 80 holes per inch, a flow rate of about 0.03 kg / min / cm2 is used. The filtered alloy was sampled in two tests, and 5 the presence of impurities was tested using an inclusion concentration technique. Both samples were completely free of inclusions. Example 31: A tubular filter with an outer diameter of 4 inches and an inner diameter of 2 inches was prepared by pyrolyzing 10 mesh polyurethane foam beads with a hole number of 26 bars per cm or 65 holes per inch. The generated carbon foam material was coated with silicon carbide by a chemical vapor deposition method, thereby generating a filter having a filtration porosity of 87% and a solid rate of 0.995 band. The tubular filter was cut to a length of 205 mm and tested as a molten aluminum metal filter in a filter box shown in the attached drawing in the vertical cutout of Figure 7 15. The filter box 40 lined with refractory material has an inlet chamber 41 and an outlet chamber 42. The two chambers are separated by a refractory partition 43. The tubular filter 44 is positioned horizontally near 45 at the bottom of the filter box 40, and one end is inserted into the refractory plate 46, the other end is inserted into a notch 47 of the partition 43. A fiber 20-dimensional gasket (not shown) is installed around the end of the filter tube 44 to seal the filter tube 44 in place and prevent molten metal from bypassing. The partition 43 is aligned with the end of the filter tube 44 in a manner 48. The height of the inlet chamber 41 beyond the filter tube 44 is 240 mm. The inside of the filter box 40 and the filter tube 44 are preheated by the two gas burners inserted into the inlet chamber 41 and the outlet chamber 42 to the filter tube to be red hot. Be careful to avoid direct burners in the entrance room 41 _______ IS_____ This paper size is in use (CNS) 21GX297 (please read the note on the back before filling this page)-order-line. 446570 A7 B7 V. Invention Explanation (β) flame affects filter tube 44. There were no signs of chipping on the surface of the filter tube 44 after preheating. A molten aluminum alloy having a purity of 99.5% is poured into a filter box 40 from a 800 kg capacity inclined furnace at a temperature of 746 ° C. When the height of the molten alloy exceeds 5 mm, the filter tube 44 reaches approximately 200 mm. The molten alloy begins to be injected into the filter tube 44 '. If the air trapped in the filter tube 44 escapes to the surface, and the molten metal appears in the outlet chamber 42. Means. Once stable, the height difference between the tops of the molten metal in the two chambers is about 25 mm. Sequential casting of three rough embryos' each rough embryo is about 3.5 meters in length and about 190 millimeters in diameter. The filling rate is about 95 millimeters per minute, which is about 8 for a total of 800 kg of molten fusion gold. The flow rate of kg / min is about 15 minutes in the casting interval. 'The immersion tube 44 is immersed in the molten metal for a total of 2.5 hours. After the third rough embryo front is formed,' the filter tube 44 is a self-contained box 40. Move in 15 and watch. There were no signs of degradation in the bowl material. The effectiveness of the filter material in removing inclusions from the grafted aluminum alloy was confirmed by microscopic inspection of the filter tube. (Please read the precautions on the back before filling in this card.) LINE PRINTED Printed by Shellfish Consumer Cooperative, Central Bureau of Standards, Ministry of Economic Affairs' 1 /. This paper size applies to China Standard for Households (CNS) Α4 (210 × 297 mm)

V. Description of the invention (1 8 No. 87119689 patent application R OP Patent ν ^ ρρΐη 5t7 I 1 A7 B7 Description of the main part of the diagram Code description Chinese manual correction page • Attachment (1)

Amended Pages of Chinese Specification-Encl. (8 $ -f- δ- M 2 ~ ai £ X) ~ (Submitted on 2, 2000) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 1 Container 2 Molten metal inlet 3 Molten metal Outlet 4 Refractory lining cover 5 Heating device 6 Inlet room 7 Outlet room 8 Refractory partition 9 Hole 10 Filter tube 11 Refractory plate 12 Refractory plate 13 Support device 21 Container 22 Outlet 23 Cover 24 Outlet room 25 Inlet room 26 Partition 27 28 Filtration Tube 29 to fire plate 30 Refractory plate 31 Supporting device 32 to 35 Sub L 36 to 37 Plug 38 Burner 40 Box 41 Entrance chamber 42 Exit chamber 43 Fire partition -------- r --- *- ------- „— —Order --------- Line Y (Please read the notes on the back before filling in this page) Λ74« «/ men This paper standard is commonly used in the painter standard (CNS > A4 size < 210 X 297 male *) I 4 4 6 5 7 0 A7

B7 V. Description of the invention (19) 44 Filter tube 45 Bottom 46 Refractory plate 47 Notch 48 iL (Please read the precautions on the back before filling this page) I ------ ^ II Order ·--- --- Printed by the Consumers' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, the paper size applies to the Chinese National Standard < CNS) A4 (210 X 297 mm)

Claims (1)

446 Λ8 Β8 C8 D8 No. 丨 19689 Patent Application ROC Patent Appln. No. 87119689 俺 正中 诛 fe ffl Φ々 本 · 件 f 二 Amended Claims in Chinese -Enel II n〇) (Submitted on Hey X, 2000) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 6. Application for a patent. A method of filtering bright metal, including providing a filter. The filter contains a porous carbon foam matrix, which is chemically heated. The method of coating is known to be applied almost completely-refractory metal or flame compound 'and cause molten metal to flow through the lacrimal device to remove inclusions contained in the molten metal.' This method is characterized by the As defined above, it is less than 90%; considering the porosity and at least 0.95 lacing solid rate. For example, the method of claim 1 in the scope of patent application is characterized in that the transition device has a passivity of at least 75%; porosity is considered. The method according to item 2 of the patent application is characterized in that the filter has a filtering porosity of at least 80%. The method according to any one of claims 1 to 3, wherein the carbon foam material matrix is a reticulated carbon foam material. The method according to any one of claims 1 to 3, wherein the refractory metal is crane or indium. 6. The method according to any one of claims 1 to 3, characterized in that the refractory compound is silicon carbide, silicon nitride, zirconium carbide, nitride, boride, niobium carbide, niobium nitride, Niobium boride 'titanium carbide, titanium nitride, titanium boride, hafnium carbide, hafnium nitride or hafnium boride. 7. The method as claimed in any one of claims 1-3, characterized in that the carbon foam material substrate is coated to a density of at least 0.25 g / cm3. But apply for any of the items 1 to 3 in the scope of patents 2. 3. 4. 5. 8. (please read the precautions on the back before filling this page) 22 This paper is used in BJ countries (CNS) ) Α4 specification (2 丨 0 × 297 mm) 87488 / menu 4 46 57 〇 Λ8 Β8 Tao factory d_D8 6. The scope of patent application is characterized by the minimum crushing strength of the filter of at least 35 kg / cm². 9. The method according to any one of claims 1 to 3, wherein the filter is in the form of a plate or a tube. 10. A filtering device comprising a metal melting container (1,2,1,4 0) with / outlet (2, 41) and an outlet (3, 22, 42), and at least one filter cover ' The housing contains a filter (10, 28, 44), which includes a porous carbon foam substrate 'approximately and completely coated with a refractory metal or refractory compound by chemical vapor deposition method to filter the filter ( 1 0, 28, 44) Supported by a device positioned and sealed 'and a device for preheating the holding container (1,21,40) and the filter (10, 28,44) before using the device to filter molten metal (5, 38) 'It is characterized in that the filter (10, 28, 44) has a filtration porosity of less than 90% as defined above and a lace solid rate of at least 0.95. π. The device according to the scope of the patent application, characterized in that the filter (10, 28, 44) has a filtering porosity of at least 75 ° / d. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs ---- Buί—— > (Please read the precautions on the back before filling out this page) 12. If the device for the scope of patent application for item 11 is characterized by the filter The device (10, 2 8, 4 4) has a transitional porosity of at least 80%. 1 3 If the device of any one of the items 10 to 12 of the patent application scope is applied, it is characterized in that the carbon foam material matrix is a reticulated carbon foam bead rod material. 23 This paper size applies to China National Standards (CNS) A4 (2 丨 〇297297mm) '-7 ^ 44657 Ο Λ8 Β8 C8 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 6. Application for patents D8 1 14. The device according to any one of patents Nos. 10 to 12 is requested. 1 1 is characterized in that the refractory metal is tungsten or molybdenum. 15. 15. Please refer to the equipment 1 of any of the patent scope Nos. 10 to 2 1 1 characterized in that the refractory compound is silicon carbide, nitride nitride, carbon first read 1 j Chemical '' fluoride nitride 'boron Zirconium carbide, anthracitic niobium nitride, boronization read on the back side 1 Niobium titanium carbide 'titanium nitride' titanium boride, Shi Fahua 铨 ♦ C 钤 钤 Note [or hafnium boride. Matters needing attention 1 r I 16. Please refer to the equipment of any one of the patent range 10 to 12 顼 5 4 Fill 1! It is characterized in that the carbon foam material substrate is coated to at least 0 · 25% of this η 1 g / Cubic centimeter density. 1 17. The device according to any one of the patents Nos. 10 to 12 > 1 I is characterized in that the minimum crushing strength of the filter (1 0, 28, 44) is at least 35 kg / Cm2. Order I 18. The device 9 1 1 as claimed in any of the patent scope items 10 to 12 is characterized in that the filter (1 0, 28, 44) is in the form of a plate or a tube 1 1 〇 I I 19. For example, the equipment in the scope of patent claim 18 is characterized in that the 1 container (1, 21) is divided into an inlet by a refractory partition (8, 26) extending across the 1 (1, 21) container. Chamber (6, .2 5) and 1 I *-exit chamber (7, 24) 'The partition (8, 26) has a hole (9, 27) 1 \ connecting the entrance chamber (6, 25) and the Outlet%: (7, 24), tubular filter 1 (10, 28) is positioned close to the base of the container (1, 21) 1 I. Insert a fire-resistant 1 at each end of the tubular filter (10, 28) One of the notches in the I plate (1 1, 29), and the opposite end is located in one of the perforated notches of the refractory 1 1 (1, 30), so that the hole in the notch and the 1 1 J 24 paper scale speed Using China National Standards (CNS) A4 * l (210X297 male dustpan) 446 57 〇 Α8 Β8 __I! ___ 6. Application for patent scope partition (8, 26) The holes (9, 27) are aligned, and the tubular filter (10, 28) is supported and sealed in position by a supporting device (1 3, 3 1) mounted above the tubular filter (10, 28). . 20. The device according to item 19 of the scope of patent application, characterized in that the container (21) has a refractory-lined lid (23), the lid has two holes (32, 33), and the holes are respectively located in the chamber (25). , 24] The holes (34,35) in the top of the container and the two plugs (36, 37) are in a line. When the plug is raised, the holes (32, 33) in the lid (2 3) are closed, and when it is lowered, the plug is closed. The hole (34 '35) in the top of the container. (Please read the precautions and fill in a copy of the book 1) \ Water. Order the paper printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. Furniture ratio (CNS > A4 now available (210X297 mm)