RU2720288C2 - Method of producing filter element with metal mesh and device for implementation thereof - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: group of inventions relates to a method of producing a mesh filter element with a metal shell from a metal mesh wire billet, as well as to scissors, process accessories and tweezers for making the element. Method comprises cutting a round billet by means of circular shears, installing the obtained billet with tweezers for installation of a mesh circular wire round workpiece of the filter element, having plates with tabs, fastening the workpiece on both sides with plastic screens and placing them in process equipment, containing container with electrolyte as cathode coaxially between anodes, wherein two round anodes with diameter larger than billet diameter are used, screens have shape of cones, base diameter of which is smaller than billet diameter by two shell widths, and after metal shell application plastic shell metal is deformed under press with compressive force and pressing it into space between workpiece mesh wires.

EFFECT: technical result consists in high strength of fastening of wires of grid and in their reliable electrical contact with shell.

7 cl, 5 dwg

Description

A method of manufacturing a filter element with a metal mesh and devices for its implementation as a group of inventions relates to the field of manufacturing devices used for filtering liquid, gas, as well as bulk solids. The filter elements woven from metal wires are widely used because they provide high filter strength, the stability of the size of the filter cells with a relatively high proportion of the total passage area of the cells to the total working area of the filter element. Because of the optimal organization of the flow of the product being cleaned, the filter elements are usually round in shape. In this case, the peripheral sections of the round mesh should have a shell that reliably keeps the wire mesh from shifting.

Shells are made either in the form of screwed rings (copyright certificate No. 1243841), or screwed flanges having grooves and protrusions for better mesh fixation (patent No. 2420347). In the practice of manufacturing laboratory equipment (elementum.kz/sieves- laboratory) in filter elements with non-replaceable metal grids, they are rolled by plastic deformation of the shell, which is the screen body. The same manufacturer offers sieves with fastening the mesh to the shell of the sieve by soldering, and to provide the possibility of using removable nets with different mesh sizes, it uses more complex designs with a separate removable ring, hooks and clips bending the edges of the mesh. The disadvantage of this method of attaching the mesh is the complexity and cumbersome design of the shell.

Compact filtering elements with a metal mesh are obtained by fixing the peripheral part of the circular mesh between the walls of a double metal ring obtained by welding two rings on their periphery, or made of a piece of thin-walled pipe, the middle part of which is extruded in the direction of increasing radius, and the edges are shifted in the direction of decreasing radius. After installing the mesh in such a blank, the edges of the ring are pressed against each other, clamping the mesh and forming its shell. In this way, the filter elements are mass-produced (www.oushijia.cn). The production of filtering shells by this method requires sophisticated specialized technological equipment, which is not acceptable in pilot production, when new processes for cleaning liquids and gases are being developed.

In some cases, the shell must provide not only a solid fastening of the wire mesh, but also their reliable electrical contact with the shell. Such a condition must be fulfilled when the mesh of the filter element is used as the carrier of the mesh of catalyst particles fixed to the wires. In this case, the catalyst is applied to the filter element using a galvanic process [RF Patents No. 2574629, No. 2613553]. In its final form, the catalytic filter consists of a package of filter elements with spacers between them, protecting the mesh from mutual contact and significant deflection under the action of the flow of the medium being cleaned. It can be water with organic pollutants dissolved in it, air with volatile pollutants, etc.

The objective of the proposed method and devices for its implementation is the production in the conditions of pilot production of round mesh filter elements using a typical galvanic deposition process on the periphery of a round mesh of metal electrolyte (for example, copper) "forming a shell of the required size. This should not be ensured not only high strength of fastening of the wire mesh, but also their reliable electrical contact with the shell, which is necessary for subsequent operations nan Senia catalyst mesh.

The proposed method of manufacturing a filter element with a metal shell of a metal mesh wire billet, includes cutting using proposed in this invention circular scissors of a round mesh blank of the filter element. Then, the obtained workpiece is cleaned using a typical galvanic process technology and the workpiece is installed using the tweezers of the invention proposed between the plastic screens. Sandwiched between screens having the shape of cones, the base diameter of which is less than the diameter of the workpiece by two shell widths, the workpiece is placed in technological equipment for the galvanic deposition of the shell metal of a round billet. The workpiece is located in a container with an electrolyte as a cathode coaxially between the anodes. In this case, two circular anodes with a diameter larger than the diameter of the workpiece are used, and the round workpiece is symmetrically between them. Copper is used as a shell metal in its galvanic deposition.

After applying the shell metal, the billet is washed and dried in accordance with the standard technology of the galvanic process, and plastic deformation of the shell metal under the press is performed by compressive force and pressing it into the space between the wires of the billet mesh.

Thus, the wire mesh produced by the proposed method of the filter element is firmly held by the metal shell, which also provides reliable electrical contact of the shell with all the wire mesh. In addition, with plastic deformation of the shell in the form of a ring, its perimeter and, accordingly, the diameter of the shell increases, which leads to the tension of the mesh of the filter element, eliminating its unwanted sagging.

For the manufacture of round sheet metal parts, stamping is widely used - this is a very productive process that can be used for nets, if they are thick enough. When micro-grids are used in the design of catalytic filters, for example, from AISI 304 or AISI 321 stainless steel with a wire diameter of 100.0 ± 0.5 μm and a mesh size of 230.0 ± 0.5 μm, stamping becomes impossible. This is due to the fact that for cutting wires, the gap between the matrix and the punch must be significantly smaller than the diameter of the wires. In this case, the gaps in the guide apparatus of the stamp, excluding the grazing of the edges of the stamp and punch, should be practically absent.

The use of laser cutting for the manufacture of circles from wire mesh is limited by the fact that the beam, passing through the empty spaces of the mesh, acts and destroys the substrate material, the beam energy is used irrationally.

The most acceptable in pilot production for cutting circles from fine mesh is the use of scissors that contain locking cutting edges located on different sides of the cut sheet. For example, manual scissors according to the patent of the Russian Federation 2159168 have a special profile of cutting edges, which allows to reduce the forces applied to their levers. However, these scissors are poorly adapted for cutting circles of small diameter. Manual cutting of a circle with ordinary scissors is time consuming, does not guarantee high accuracy of the shape of the circle and its diameter.

For cutting circles from sheet material, commercially available equipment is used, for example, Prinzing KSE 12/10 or NRK-1000 - manufacturer Intechmash, which has two rollers with cutting edges. One roller is located under the sheet from which the circle is cut, and the second roller is above the sheet. One roller is driven by the drive, and the arc roller moves so that the cutting edges located in parallel planes overlap each other, passing a path greater than the thickness of the cut sheet. The blank of the sheet from which the circle is cut is clamped from above in the center of the circle on a support that can rotate together with the cut circle driven by a rotating cutting roller.

The equipment under consideration has a complex structure, but like stamping it cannot be used as circular scissors for fine mesh with thin wires, since the gap between the planes of the cutting edges of the rollers in such equipment is comparable and even greater than the thickness of the wires.

The design of the proposed circular shears is shown in FIG. 1 (front view) and FIG. 2 (top view). The design comprises a base 1 made of a sheet with struts rigidly attached to it, to which a tubular housing 2 is also attached on top with sliding bearings 3 in which a shaft 4 is mounted. A cutting disk 5 is coaxially attached to one end of the shaft and the other end the shaft is equipped with a handle 6, which allows you to rotate the shaft with the disk. The diameter of the disk 5 along its cutting edge formed by the outer plane and the conical surface of the periphery of the disk is equal to the diameter of the circle of the cut mesh. Coaxially with the cutting disk is located a somewhat smaller diameter clamping disk 7, in the hub of which a blind cylindrical groove is made, the bottom of which has a conical recess.

The pressure shaft 8 freely enters the cylindrical groove, at both ends of which there are also conical recesses. The shaft is passed through two bearings 9 mounted in a tubular housing 10, rigidly mounted on a rack with a platform screwed to the spacers rigidly attached to the base 1. In this case, the shaft 8 should be aligned with the shaft 4.

On the side opposite to the pressure disk, on the outer surface of the housing 10 there is a thread on which a cap 11 is screwed, a handle 12 attached to it and a hardened stop 13 located along the axis of the cap. The ball 14 is placed in contact with the stop located in a conical recess on the end of the pressure shaft. The same ball is placed in a conical recess on the other end of the shaft and in the conical recess of the hub of the pressure disk 7, and the screws 15 included in the annular groove of the pressure shaft close the hub of the pressure disk with the shaft, excluding spontaneous rolling out of the conical grooves of the balls when the pressure disk moves away from cutting disc.

The second cutting disk 16 is rigidly connected along its axis with a roller mounted in a sliding bearing located in a tubular body 17 fixed to the end of the two shoulders lever 18, the second end of which is a handle. The axis 19 holds the lever in the slot of the rod 20, ensuring the swing of the lever in a vertical plane.

The rod is movably inserted into the tubular stand 21 and is supported by the flange provided for this in the upper end of the rack, while the screw 22 enters the groove of the rod, which keeps the rod from shifting upwards and allows the lever to rotate with the cutting disc in a horizontal plane. A bracket is provided on the tubular stand, into which a screw 23 is screwed, restricting the rotation of the lever in a vertical plane until the cutting disc 16 is lowered to the working position.

The tubular rack is rigidly bonded to the platform 24 laid on the plate 25, rigidly fixed through spacers with the base 1, and under the plate 25 is placed a plate 26 having four threaded holes. Screws 27 with flat washers are screwed into these holes, passing through the holes in the platform 24 and the plate 25. The holes are made in the form of grooves in width corresponding to the diameter of the screws. The grooves in the plate 25 are directed along the base 1, and in the platform 24 - across the base.

Pie shears are used as follows:

First, the position of the cutting disc 16 relative to the disc 5 is adjusted. To do this, with the screws 27 loosened, the tubular stand 21 with its platform along the plate 25 is displaced to such a position that the cutting edge of the disc 16 with a slight overlap touches the cutting edge of the disc 5. At the same time, the adjusting screw 23 brought to touch with the lever 18, after which the screws 27 are tightened.

Previously, with ordinary scissors (you can use scissors to trim photos and cardboard), the grid is cut into squares with side sizes 5 ... 10% larger than the diameter of the required circle. Unscrew the cap 11 and push the pressure disk 7 so that the square of the mesh passes freely into. gap between the cutting and pressure discs. The mesh is inserted into the slot and, by turning the handle 12, screw the cap 11. The force is transmitted through the ball 14 and the pressure shaft 8 to the ball located in the conical recess of the hub of the pressure disk 7. Due to the fact that the disk can be rotated on the spherical surface of the ball, it is based along the plane of the disk 5 and evenly presses the grid over the entire surface of the disk.

After that, turning the lever 18 with the handle, the cutting disk 16 is pressed against the edge of the cutting disk 5 and, rotating the handle 6 by 360 °, the mesh parts protruding beyond the boundaries of the cutting disk 5 are cut. Next, by turning the handle 12, unscrew the cap 11 until the mesh is released and take out the cut circle.

The tooling for the manufacture of the metal shell of the mesh filter element by galvanic deposition of metal on the mesh is shown in FIG. 3 (front view) and FIG. 4 (side view). The equipment includes: an electrolyte container 28, a plastic frame 29, on which round anodes 31 are fixed with screws 30, clamping screws 32 are located at the centers of the anodes, conical screens 33 and 34. An elastic rubber gasket 35 is placed in the recess of the screen 33 and is glued to it the outer surface of the metal foil 36 connected to an insulated wire 37, passed through the provided hole 38 in the cone and then connected to the negative terminal of the current source. Between the conical screens, a mesh 39 is clamped onto which metal is deposited in a galvanic process. The entire fixture assembly is hung by the terminals of the anodes 40 on the conductive rod 41, resting on the edges of the capacitance and connected to the plus terminal of the current source.

Used technological equipment for the manufacture of the metal shell of the mesh filter element as follows. The conductive rod 41 with the fixture assembly is laid on the bracket provided for this (in Fig. 3 and Fig. 4 not shown) located above the container 28. The clamping screw 32 is loosened by 1-2 turns and a special tweezers are formed into the gap between the conical screens from below a round mesh is inserted that has undergone preliminary processing, provided for by the standard technology of galvanic deposition of metal from an electrolyte (cleaning, dipping, etc.).

After the grid is centered with a special tweezers with conical screens, the screw 32 is screwed to the state “as tight”, while the grid is clamped between the screens, and the metal foil, pressed by an elastic rubber gasket, provides reliable electrical contact with all the wires of the grid. Next, the conductive rod with the complete assembly is removed from the bracket and lowered to the edges of the tank with the frame immersed and the anodes and cathode fixed on it into the electrolyte, where the process of galvanic deposition of metal on the protruding edges of the grid is carried out, forming its shell.

After obtaining the desired thickness of the metal of the shell, the conductive rod with snap assembly is removed from the electrolyte and placed on the bracket to remove the finished grid and install the next grid.

The tweezers for mounting the mesh between the conical screens used in the process of galvanic deposition on the mesh of the shell metal is shown in FIG. 5. It contains two oblong plates (42 and 43), in the middle part of which there are two eyelets bent at right angles with holes through which the common axis 44 of the plate is movably connected to each other. A double torsion spring 45 is installed on the axis, the middle part of which abuts against the plate 42, and its side wires - against the plate 43, which leads to rotation of the plates until their legs are closed.

The tabs of the plates are divided into two parts symmetrically to the longitudinal axis of the plates, i.e., the two tabs indicated in FIG. 5 positions 46 and 47, respectively, for plates 42 and 43. The paws of each plate are spaced apart, in the middle of their working surfaces, at the same distance for both plates of approximately 0.7 mesh diameters and have a working foot length of 0.15- 0.17 mesh diameters. The width of the clamping surface of the tabs 4 of the first tweezers plate is limited by the bends of the plate at right angles in different directions and is equal to the width h of the shell. The width of the legs 47 of the second tweezers plate, limited by bending the plate at a right angle from the plane of the grid in the tweezers and the edge of the foot, is smaller and sufficient to prevent the tabs of the plates from touching each other when the tweezers open.

The common plane formed by the curved parts of each pair of paws is perpendicular to the radius drawn from the center of the clamped mesh to the middle along the length of the paws.

Use tweezers as follows. The ends of the plates 42 and 43, which are the “keys” of the tweezers, are compressed, while the plates rotate, and a gap is formed between the tweezers, where the mesh prepared for deposition (cleaned, past decapitation, etc.) is inserted. In this case, the mesh should be captured with ordinary tweezers or fingers, provided that the fingers do not touch the areas of the future shell.

After the mesh rests against the bends of the legs 46, the “keys” are released and the legs 47 clamp the mesh. In this position, the mesh is transferred with tweezers and pushed from below into the gap between the screens of the tooling used to deposit the shell metal, until the bends of the tweezers paws in the screens stop. In this state, the grid is aligned with the screens and can be clamped between them by tightening the clamping screw of the snap.

An example implementation of a method of manufacturing a filter element with a metal mesh of round shape. The filtering round element with a diameter of 100 mm is made of a micro mesh made of AISI 321 stainless steel with a wire diameter of 100.0 ± 0.5 μm and a mesh size of 230.0 ± 0.5 μm.

A preliminary blank in the form of a square with a side of 105 mm was cut with scissors, from which a circular blank with a diameter of 100 mm was cut on circular scissors. The mesh was degreased with trichlorethylene followed by washing with water immediately before the start of the galvanic process.

The electrolyte composition for applying the copper shell of the filter element per 1 liter of the finished electrolyte:

- sulfate 5-water copper (II) (vitriol) - 250 g:

- sulfuric acid - 98 g;

- distilled water - the rest.

Electrolyte Preparation Procedure:

1) pour distilled water (approximately half of the required volume) into a chemically resistant and heat-resistant vessel;

2) heat the water to 50-70 ° C;

3) stirring water, add the calculated amount of copper sulfate and mix until it is completely dissolved;

4) cool the resulting solution to room temperature;

5) while stirring the solution, slowly pour the calculated amount of sulfuric acid;

6) add water to the vessel to the required volume;

7) to clean the electrolyte from unwanted contaminants, add 4-5 tablets of 5 g. activated carbon, grind and place the resulting solution;

8) let the finished electrolyte with activated carbon settle for 24 hours;

9) filter the electrolyte using an anesthetized filter paper to remove activated carbon particles, as well as other possible random impurities;

10) pour the finished electrolyte into the tank for conducting the galvanic process.

Before the start of the galvanic process, the defatted and water-washed mesh was chemically decapitated by lowering it for 5-15 seconds in a solution of sulfuric acid to remove oxide films. After washing in running water for 2-3 minutes, the mesh was ultrasonically cleaned for 5-7 minutes in a bath with distilled water of the Sapphire TTZ installation.

After that, a special tweezers mesh was installed and sandwiched between the conical screens of the equipment for galvanic deposition with copper anodes. The diameter of the bases of the cones is 90 mm, which provided a shell width of 5 mm. In this position, the tool is lowered into the electrolyte.

Copper was deposited on the surface of the mesh at a current density of 6 A / dm ² for 20 min, while the electrolyte was sparged with air passing through it and a shell metal thickness of about 5 times the original mesh thickness was reached. Next, the mesh was washed in running water and dried. Copper deposition time can be shortened by using sulfamic acid copper electrolytes or electrolytes used at high anode current densities in electroplating.

The final step in the manufacture of the filter element with a metal mesh was the compression of the shell metal under the press. The grid was laid on a special ring mandrel to the size of the shell and was compressed by a force of 10 tf. With the initial shell thickness of 1.20 mm, the shell thickness after plastic deformation was 0.75 mm.

Strength tests of the obtained shell were carried out by applying a load with a punch with a diameter of 50 mm in the central part of the mesh, laid by its shell on an annular support. The loss of the shape of the shell (the formation of corrugations and the beginning of the sliding of the mesh into the hole of the annular support) occurred at a force of 70 N. Moreover, pulling out the wires of the mesh in the metal of the shell and its cracks were not observed. After the experiment, the shell was straightened and the round shape of the filter element was restored.

Naturally, if in the design of the filter the shell will be in a clamped state, then the resistance of the filter element will be significantly higher.

Thus, the proposed group of inventions solves the task of manufacturing in the conditions of pilot production of compact round filtering elements from a fine mesh using a typical galvanic process of deposition of a metal from an electrolyte (for example, copper), forming a shell of the required size in thickness and width. This ensures not only high strength of the wire mesh fastening, but also reliable electrical contact of all wires with the shell, which is necessary in the case of subsequent operations of applying the catalyst to the grid by the galvanic method. The package of elements with grids carrying catalyst particles is a catalytic reactor that removes water-soluble organic pollutants or volatile air pollution.

Having a set of compact mesh filter elements made by the proposed method of equal diameter, but with different mesh sizes between the wire mesh, it is possible to complete the sieves with the required screening ability using a single sieve housing.

Claims (7)

1. A method of manufacturing a mesh filter element with a metal shell from a metal mesh wire billet, comprising cutting a round billet with circular scissors for cutting a metal mesh wire round billet of a filter element, installing the resulting blank with tweezers for installing a mesh wire round billet of a filter element having plates with pads made with the possibility of clamping the workpiece between the plastic screens for galvanic precipitation shell on the shell metal blank, fixing the blank on both sides with plastic screens and placing them in technological equipment for galvanic deposition of the shell metal on a metal wire mesh round blank containing a container with an electrolyte as the cathode coaxially between the anodes, using two circular anodes with a diameter larger than the diameter of the workpiece, the screens are in the form of cones, the base diameter of which is less than the diameter of the workpiece by two shell widths, and after applying the shell metal, plastic deformation of the shell metal under the press with compressive force and its pressing into the space between the wires of the workpiece mesh. 2. The method according to p. 1, characterized in that the metal used in the deposition of copper. 3. Circular scissors for cutting a metal mesh wire round blank of the filter element, containing a base with racks, two rotating cutting discs with sharp edges, a fastening mechanism for the original mesh blank, characterized in that a tubular housing in which the shaft is mounted is attached to one rack one end of which the first cutting disc is coaxially attached, and the other end of the shaft is configured to rotate the first disc, while the mounting mechanism is made in the form of a clamping disk, installed coaxially aligned with the first cutting disk, with a diameter smaller than the diameter of the first cutting disk, the diameter of the first cutting disk being equal to the diameter of the circle cut from the workpiece, and the second cutting disk, the plane of which is perpendicular to the plane of the first disk, is fixed at one end of the two shoulders lever, while the lever is fixed to the rod by means of an axis, which is movably inserted into the second rack, made tubular and mounted on a plate rigidly connected to the base, while the bracket d is fixed to the tube rack I restriction lever pivot in a vertical plane and the tubular strut is displaceable along the plate by adjusting screws mounted therein, wherein the second end of the lever is designed as a handle. 4. Scissors p. 3, characterized in that they are made with the possibility of cutting a round workpiece from the workpiece in the form of a square. 5. Scissors according to claim 3, characterized in that the shaft is rotatable by means of a handle. 6. Tooling for galvanic deposition of shell metal on a round wire mesh blank of the filter element, containing an electrolyte container, two anodes connected to a direct current source and a blank placed between them as a cathode, characterized in that the anodes have a circle shape with a diameter of at least diameter blanks and are fixed against each other on the inner sides of the plastic frame, while in the center of each anode there is a threaded hole in which the clamp screw is installed a sheep, on the end of which a conical plastic screen is mounted with its top part, the base of which is facing the workpiece and has a diameter less than the diameter of the workpiece by two widths of the fabricated shell, while on the basis of one of the cones a cylindrical recess with a diameter equal to 0.9 of the diameter of the base is made, in which an elastic rubber pad is laid in a thickness exceeding the recess with a metal foil glued to its outer surface connected to an insulated wire passed through a hole in the cone and connected to the minus terminal of the current source. 7. Tweezers for mounting a wire mesh round blank of the filter element between conical screens for galvanic deposition on the shell metal blank containing two oblong plates with flat tabs, in the middle part of which there are two eyelets bent at right angles with holes in which the common axis of the plates is installed and a spring for closing the legs, characterized in that the legs are divided symmetrically into the longitudinal axis of the plate into parts, while the working length of the legs is 0.15-0.17 diameter of the workpiece, two hours These first legs are made curved in different directions at a right angle and with a width of the clamping surface equal to the width of the shell, and the legs are made with the possibility of forming a gap between them equal to 0.7 of the diameter of the workpiece.

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