Preparation method of tubular filter shell

Abstract

The invention discloses a preparation method of a tubular filter shell, which comprises the following steps of: blanking a steel-titanium composite plate, aligning a material plate, preparing a groove, rolling and forming, welding a longitudinal seam, correcting a circle, carrying out primary assembly, welding a circular seam, carrying out nondestructive testing, carrying out secondary assembly welding, inspecting to be qualified, polishing, scribing and trepanning, welding accessories such as a connecting pipe, carrying out a leakage test, pickling and passivating, sandblasting and painting, sealing and marking. And finishing the preparation of the tubular filter shell. The steel-titanium composite plate is adopted as a preparation material of the tubular filter shell, the steel plate can ensure the mechanical strength of the tubular filter, the titanium plate has excellent corrosion resistance and can resist corrosion of corrosive media such as acid and alkali, the reliability of equipment is improved, and the service life of the tubular filter is prolonged; the titanium material is non-toxic and harmless, meets the environmental protection requirement and can be suitable for industries such as food, medicine, chemical engineering, nonferrous metallurgy and environmental protection.

Description

Technical Field

[0001] The invention relates to the technical field of filters, in particular to a method for preparing a tubular filter housing. Background Art

[0002] Traditional tubular filter housings are typically manufactured from carbon structural steel or low-alloy steel, and lined with 5mm thick nitrile rubber on the inner wall to improve the corrosion resistance of the tubular filter. The rubber lining of tubular filter housings with this structure is prone to aging and peeling over time, resulting in reduced filtration efficiency and equipment damage. Frequent lining replacement and maintenance are required, impacting production capacity. Tubular filters with this structure have a short service life, generally not exceeding three years. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing a tubular filter housing, which is made of a steel-titanium composite material, has strong corrosion resistance and a service life much longer than that of traditional tubular filters.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing a tubular filter housing comprises the following steps: Step 1: Select steel plates and titanium plates of appropriate thickness, perform surface treatment, and then use explosive welding or hot rolling composite process to composite the steel plates and titanium plates into steel-titanium composite plates; Step 2: Cut the steel-titanium composite plate according to the prepared shell blanking layout using a CNC laser cutting machine, cut the plates of the lower cylinder, upper cylinder, conical shell and elliptical head, use the steel plate as the outer wall and the titanium plate as the inner wall, and grind the welding grooves on all sides of each plate; Step 3: Roll each sheet into shape, weld the longitudinal seam first, process the two edges of the sheet to be welded, and then weld the sheet using tungsten inert gas arc welding (TIAN) with titanium wire. After welding, align the sheet to make it round. Step 4: Assemble and weld the elliptical head, upper cylinder, lower cylinder and cone shell after rounding. The welding method of the circumferential seam is the same as that of the longitudinal seam to form a tubular filter shell. Step 5: Perform non-destructive testing on the tubular filter housing, perform secondary welding on unqualified welds, and after passing the test, mechanically polish the inner and outer surfaces of the housing to ensure that the surface roughness Ra ≤ 0.8μm; mark and open holes at the pipe openings of the elliptical head and cone shell, weld accessories, perform leakage tests, pickling, passivation, sandblasting, and painting, assemble ear supports and grounding plates on the lower cylinder, seal and mark, and complete the production of the tubular filter housing.

[0005] The preferred method for processing the two edges of the material plate to be welded in step three is: the steel plates are brought into contact at the butt joint of the two edges of the material plate, and a thin layer of refractory metal lining is inserted between the grooves of the titanium plate above the steel plate seam; during welding, the welding gun is controlled to move along the titanium wire, and the tungsten electrode arc burns between the titanium wire and the tungsten electrode, and does not act directly on the thin layer of refractory metal lining. After the titanium wire melts, the weld of the steel-titanium composite plate is formed.

[0006] Preferably, the thin layer of refractory metal lining is niobium foil or molybdenum foil with a thickness of 0.1 mm.

[0007] Preferably, in step three, the method for processing the two edges of the material plate to be welded is: a gap is left near the butt joint of the two edges of the material plate, a titanium cover plate is placed above the groove formed by the groove of the titanium plate, and a filling material is placed in the groove.

[0008] Preferably, the filling material placed in the groove is silver, silver solder or epoxy resin type polymer.

[0009] Preferably, the steel layer of the steel-titanium composite plate has a thickness of 12-20 mm and is a carbon structural steel or low alloy steel plate, and the titanium material has a thickness of 2-4 mm and is a Gr2 type industrial pure titanium plate.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a steel-titanium composite plate as the preparation material of the tubular filter housing. The steel plate can ensure the mechanical strength of the tubular filter, and the titanium plate has excellent corrosion resistance and can resist the erosion of corrosive media such as acids and alkalis, thereby improving the reliability of the equipment and extending the service life of the tubular filter to more than 10 years. The steel-titanium composite plate used in the present invention is prepared by explosive welding or hot rolling composite process of steel plate and titanium plate, which can ensure close bonding between the steel plate and the titanium plate and avoid delamination and falling off.

[0011] Titanium is non-toxic and harmless, meets environmental protection requirements, and can be used in food, medicine, chemical industry, non-ferrous metallurgy, environmental protection and other industries.

[0012] In step three of the method described herein, the two edges of the sheet to be welded are treated as follows: the steel sheets are butted against each other at the butt joint, and a thin refractory metal lining is inserted between the grooves of the titanium sheet above the seam. This thin refractory metal lining is niobium or molybdenum foil, 0.1 mm thick. Niobium and molybdenum have high melting points, so the tungsten arc does not directly act on the niobium or molybdenum foil, melting only a small portion of the niobium or molybdenum foil. This prevents fusion of the steel and titanium sheets on either side of the weld, effectively preventing the formation of brittle phases at the weld seam of the steel-titanium composite plate and ensuring the strength and reliability of the tubular filter.

[0013] Step three of the method described herein utilizes an alternative welding process. Specifically, in step three, the two edges of the sheet to be welded are treated by leaving a gap near the butt joint of the two edges. A titanium cover plate is placed over the groove formed by the bevel of the titanium plate, and a filler material is placed in the groove. The filler material in the groove is silver, silver solder, or an epoxy-based polymer. The titanium cover plate protects the weld joint from corrosive media, the silver or silver solder blends well with the titanium plate, and the epoxy-based polymer improves the corrosion resistance of the joint. The strength of the butt joint is ensured by the weld seam of the steel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a structural diagram of a tubular filter housing; Figure 3 It is a schematic diagram of welding with titanium cover plate on the weld; Figure 4 It is a schematic diagram of welding in which a thin layer of refractory metal lining is embedded in the groove of the titanium plate on the weld. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0016] Example 1 like Figure 1 A method for preparing a tubular filter housing is shown, comprising the following steps: Step 1: Select a carbon structural steel or low alloy steel plate with a thickness of 12-20 mm and a Gr2 titanium plate with a thickness of 2-4 mm, perform surface treatment, and then use explosive welding or hot rolling composite process to composite the steel plate and the titanium plate into a steel-titanium composite plate; Step 2: Cut the steel-titanium composite plate according to the prepared shell blanking layout using a CNC laser cutting machine to cut out the plates of the lower cylinder 2, upper cylinder 3, cone shell 1 and elliptical head 4. The steel plate is used as the outer wall and the titanium plate is used as the inner wall. The welding grooves are polished on all sides of each plate. Step 3: Roll each sheet into shape and weld the longitudinal seam first. The steel sheets are butted against each other at the butt joints of the two sides of the sheet. A 0.1mm thick refractory niobium foil or molybdenum foil is inserted between the grooves of the titanium sheet above the steel seam as a lining. Tungsten inert gas arc welding is used, and titanium welding wire is selected to weld the sheet. During welding, the welding torch is controlled to move along the titanium wire, and the tungsten arc burns between the titanium wire and the tungsten electrode, avoiding direct action on the lining. Once the titanium wire melts, the weld seam of the steel-titanium composite plate is formed. After welding is completed, the roundness is adjusted. Step 4: Assemble and weld the elliptical head, upper cylinder, lower cylinder and cone shell after rounding. The welding method of the circumferential seam is the same as that of the longitudinal seam to form a tubular filter shell. Step 5: Perform non-destructive testing on the tubular filter housing, perform secondary welding on unqualified welds, and after passing the test, mechanically polish the inner and outer surfaces of the housing to ensure that the surface roughness Ra ≤ 0.8μm; mark and open holes at the pipe openings of the elliptical head and cone shell, weld the pipes and other accessories, perform leakage tests, pickling, passivation, sandblasting, and painting, assemble ear supports and grounding plates on the lower cylinder, seal and mark, and complete the production of the tubular filter housing.

[0017] Example 2 like Figure 1 A method for preparing a tubular filter housing is shown, comprising the following steps: Step 1: Select a carbon structural steel or low alloy steel plate with a thickness of 12-20 mm and a Gr2 titanium plate with a thickness of 2-4 mm, perform surface treatment, and then use explosive welding or hot rolling composite process to composite the steel plate and the titanium plate into a steel-titanium composite plate; Step 2: Cut the steel-titanium composite plate according to the prepared shell blanking layout using a CNC laser cutting machine to cut out the plates of the lower cylinder 2, upper cylinder 3, cone shell 1 and elliptical head 4. The steel plate is used as the outer wall and the titanium plate is used as the inner wall. The welding grooves are polished on all sides of each plate. Step 3: Roll each sheet into shape and weld the longitudinal seam first. Leave a gap between the two edges of the sheet and place a titanium cover plate on the groove formed by the groove of the titanium plate. Place a filling material in the groove. The filling material can be silver, silver solder or epoxy resin polymer. Use tungsten inert gas arc welding with titanium wire to weld the sheet. After welding, calibrate the roundness. Step 4: Assemble and weld the elliptical head, upper cylinder, lower cylinder and cone shell after rounding. The welding method of the circumferential seam is the same as that of the longitudinal seam to form a tubular filter shell. Step 5: Perform non-destructive testing on the tubular filter housing, perform secondary welding on unqualified welds, and after passing the test, mechanically polish the inner and outer surfaces of the housing to ensure that the surface roughness Ra ≤ 0.8μm; mark and open holes at the pipe openings of the elliptical head and cone shell, weld the pipes and other accessories, perform leakage tests, pickling, passivation, sandblasting, and painting, assemble ear supports and grounding plates on the lower cylinder, seal and mark, and complete the production of the tubular filter housing.

[0018] The application adopts steel-titanium composite plate as the preparation material of the shell of the tubular filter, the steel plate can ensure the mechanical strength of the tubular filter, the titanium plate has excellent corrosion resistance, can resist the corrosion of acid, alkali and other corrosive media, improves the reliability of the equipment, prolongs the service life of the tubular filter, and the service life can be prolonged to more than 10 years; the titanium material is non-toxic and harmless, meets the environmental protection requirements, and can be applied to food, medicine, chemical industry, non-ferrous metallurgy, environmental protection and other industries.

Claims

1. A method for preparing a tubular filter housing, characterized in that: The following steps are involved: Step 1: Select steel plates and titanium plates of appropriate thickness, perform surface treatment, and then use explosive welding or hot rolling composite process to composite the steel plates and titanium plates into steel-titanium composite plates; Step 2: Cut the steel-titanium composite plate according to the prepared shell blanking layout using a CNC laser cutting machine to cut out the lower cylinder (2), upper cylinder (3), cone shell (1) and elliptical head (4) plates, with the steel plate as the outer wall and the titanium plate as the inner wall, and grind the welding grooves on all sides of each plate; Step 3: Roll each sheet into shape, weld the longitudinal seam first, process the two edges of the sheet to be welded, and then weld the sheet using tungsten inert gas arc welding (TIAN) with titanium wire. After welding, align the sheet to make it round. Step 4: assemble and weld the elliptical head (4), upper cylinder (3), lower cylinder (2), and cone shell (1) that have been calibrated, using the same method as the longitudinal seam welding to form a tubular filter housing; Step 5: Perform non-destructive testing on the tubular filter housing, perform secondary welding on unqualified welds, and after passing the test, mechanically polish the inner and outer surfaces of the housing to ensure that the surface roughness Ra is ≤ 0.8 μm; mark and open holes at the pipe openings of the elliptical head (4) and the conical shell (1), weld the accessories, perform leakage testing, pickling, passivation, sandblasting, and painting, assemble ear-type supports and grounding plates on the lower cylinder (2), seal and mark, and complete the production of the tubular filter housing.

2. The preparation method according to claim 1, wherein: The method for processing the two edges of the material plate to be welded in step three is as follows: the steel plates are brought into contact at the butt joint of the two edges of the material plate, and a thin layer of refractory metal lining is inserted between the grooves of the titanium plate above the steel plate seam; when welding, the welding gun is controlled to move along the titanium wire, and the tungsten electrode arc burns between the titanium wire and the tungsten electrode, and does not act directly on the thin layer of refractory metal lining. After the titanium wire melts, the weld of the steel-titanium composite plate is formed.

3. The method according to claim 2, wherein: The thin layer of refractory metal lining is niobium foil or molybdenum foil with a thickness of 0.1 mm.

4. The method according to claim 1, wherein: In step three, the method for processing the two edges of the material plate to be welded is as follows: a gap is left near the butt joint of the two edges of the material plate, a titanium cover plate is placed above the groove formed by the groove of the titanium plate, and a filling material is placed in the groove.

5. The method according to claim 4, wherein: The filling material placed in the groove is titanium, silver, silver solder or epoxy resin type polymer.

6. The method according to claim 1, wherein: The steel layer of the steel-titanium composite plate has a thickness of 12-20 mm and is a carbon structural steel or low alloy steel plate, and the titanium material has a thickness of 2-4 mm and is a Gr2 type industrial pure titanium plate.

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