METHOD FOR PRODUCING A PERFORATED SHEET, PERFORATED SHEET, MOULDED PART AND PROCESSING DEVICE

Description

[0001] The invention relates to a method for producing a perforated sheet, wherein the produced perforated sheet has at least one hole. Furthermore, the invention relates to a perforated sheet, a molded part, and a processing device.

[0002] Perforated plates are used in various forms and functions in industrial applications. For example, perforated plates are used for screening, classifying, filtering, or dosing. In this case, a perforated plate is either installed directly into a processing system, for example, as a flow plate in a fluidized bed system, or is first formed as a semi-finished product, for example, into a cylindrical filter element in a water filter.

[0003] In a well-known, simple manufacturing process, for example, perforated sheets are produced from sheets or strips that are to be perforated using a wide-diameter press, which punches an entire row of holes into the strip or sheet in a single stroke. This allows for the creation of round, square, or other hole shapes with straight hole flanks in the through-hole direction.

[0004] US Pat. No. 683,793 A discloses the manufacture of a bicycle seat post, in which two openings are made in a punched sheet metal part and then connected by a slot. The slotted sheet is then partially lifted by a suitable die in a punch or press.

[0005] CH 655 256 A5 describes a method for producing rasp discs for kitchen utensils, in which holes are punched out on a disc, shells are set up by pressing out about half of the hole edge and the shells are sharpened from the inside by means of a scraping stamp.

[0006] US 2010 / 126152 A1 describes the production of a metal sheet for a carrier body of a catalyst for cleaning vehicle exhaust gases, in which slots and openings on both sides are made vertically in the edge areas of the flat metal sheet, a wave structure is then formed in the metal sheet, microstructures are produced by bending the sheet upwards adjacent to the slots and finally the wave structure is compressed.

[0007] GB 1094610 A discloses a strip with a series of projections alternating on each side, which is subsequently formed into a split ring for coupling two rotating components. The projections on both sides, which serve as tab sections, are manufactured by vertically piercing openings on both sides through the horizontally aligned strip, cutting a transverse slit between the two openings, and bending the tab sections upwards between the respective openings.

[0008] Slotted perforated sheets and fine-hole sheets are also known, the latter of which can be designed with triangular or semi-elliptical openings, for example. With these perforated sheets, and especially with fine-hole sheets where the hole width is significantly smaller than the sheet thickness, problems arise at the inner edges and / or inner corners of the hole connecting to the solid sheet due to the accumulation of bacteria and / or inorganic and organic substances in these areas. This encrustation and accumulation of bacteria lead to hygiene problems and complaints, particularly when such perforated sheets are used for processing in the food and / or pharmaceutical industries.

[0009] The object of the invention is to improve the state of the art.

[0010] The object is achieved by a method for producing a perforated sheet, wherein the produced perforated sheet has at least one hole, with the following steps Making two spaced holes in a sheet metal, the holes being formed continuously through a thickness of the sheet metal, making a continuous cut between the two spaced holes in the sheet metal, and bending a sheet metal section adjacent to the continuous cut in such a way that a hole is formed, whereby the holes are drilled at an angle in a range of 30° to 60° to a horizontal alignment of the sheet.

[0011] The method according to the invention provides a perforated sheet in which the flow through the hole is stronger than in the prior art. By creating a defined surface as the starting and ending area of ​​the subsequent hole in the solid sheet during the drilling process, the flow through and / or around this surface is increased, thus preventing the accumulation of bacteria, inorganic and / or organic substances at the corresponding edge and corner areas of the hole formed by the holes.

[0012] It is particularly advantageous that the shape and size of the hole are adapted to the shape and size of the sheet metal section adjacent to the continuous cut, with the latter being bent accordingly. Since the sheet metal section can be bent in a defined manner both vertically and horizontally with respect to the dimensions of the sheet, the shape of the hole can be defined in relation to the shape of the holes, and both can be designed in such a way that both the areas of the holes and the hole itself are optimally flowed through. Consequently, laminar flow regions are avoided when a fluid and / or particles pass through the hole, even in the corner and edge areas of the hole.

[0013] It is also particularly advantageous that the orientation and / or shape of the hole with its two openings as well as the arrangement of the hole on the sheet can be manufactured flexibly and freely. Firstly, the top and bottom of the perforated sheet can be formed differently by bending it up. For example, the underside of the perforated sheet can be smooth with a smooth lower opening of the hole, while on the top side of the sheet the bent-up sheet section and the upper opening of the hole protrude beyond the sheet thickness. In addition, the upper opening of the hole can, for example, be horizontal in its initial direction and thus parallel to the horizontal alignment of the sheet. The bent-up sheet section can, for example, also have a straight opening pointing upwards on the top side.

[0014] Thus, the two spaced holes determine the hole width in the horizontal alignment of the sheet, while the bending of the sheet section adjacent to the continuous slot primarily carries out the vertical expansion of the hole.

[0015] A key concept of the invention is to design the inner edges of the hole by creating holes with a defined shape and surface, ensuring optimal airflow through the hole even in the corner and / or edge areas, thereby preventing the accumulation of bacteria, inorganic, and / or organic substances. Furthermore, the holes prevent cracks from tearing or fraying, thus preventing bacteria from accumulating in these cracks. The following terminology is explained:

[0016] A "perforated sheet" (also called a "perforated plate") is, in particular, a sheet that has holes extending through its thickness. The holes are, in particular, introduced into the sheet in a regular arrangement. A perforated sheet also includes perforated plates according to DIN 4185-2 and 24041, according to which a perforated plate is defined as a plate that has similar openings in regular arrangements by punching, perforating, or drilling. A perforated sheet is also understood, in particular, to be a sheet that has angled, curved, or conically shaped hole flanks in the direction of passage. Thus, the hole width can narrow or widen continuously or discontinuously in the direction of passage. The perforated sheet, in particular, has different top and bottom sides. In particular, the bent area of ​​the sheet section and thus the corresponding hole flank is located only on the top or bottom of the perforated sheet.In a perforated sheet with multiple holes, all bent sheet sections for forming the hole are preferably arranged on one side of the sheet. However, the bent sheet sections can also protrude alternately on the top or bottom of the perforated sheet in a regular distribution. Particularly preferably, the bent sheet sections for forming the respective holes are arranged on the product side of the perforated sheet used in an industrial production process and protrude, for example, in a scale or semicircular pattern above the sheet thickness.

[0017] The perforated sheet preferably has a thickness in the range of 0.2 mm to 5.0 mm. Preferably, the sheet thickness is significantly larger than the hole width, allowing the production of a corresponding fine-hole sheet.

[0018] The perforated sheet comprises in particular unalloyed steel, duplex steel, stainless steel, nickel steel with other nickel alloys, aluminum, silver, tantalum, niobium and / or other materials.

[0019] To further improve the flow through the holes and the hole itself, the perforated sheet can be hardened and the surface further smoothed after the hole has been bent open. This type of post-treatment can be achieved, for example, by electropolishing.

[0020] A "hole" is understood, in particular, to be an opening extending through the thickness of a perforated sheet and / or a sheet. The hole can, in particular, have any cross-sectional area and / or the hole width can vary in the direction of passage. In particular, a hole has a round cross-sectional shape. The hole, in particular, has a diameter (hole width) in a range from 0.03 mm to 8.00 mm, preferably from 0.10 mm to 3.00 mm.

[0021] A "sheet" is, in particular, a rolled metal product whose width and length are much greater than its thickness. A sheet is, in particular, a panel, plate, strip, and / or coil (wound metal strip). A sheet has, in particular, a sheet thickness and a material that meets the requirements of the perforated sheet to be produced. Thus, a sheet has, in particular, the sheet thickness and materials mentioned above for a perforated sheet. A sheet is, in particular, a thin sheet with a sheet thickness < 3.0 mm, a medium sheet with a sheet thickness in a range of 3.0 mm to ≤ 4.75 mm, or a heavy plate with a thickness greater than 4.75 mm.

[0022] A "bore" is, in particular, a continuous opening through a thickness of the sheet metal. The bore, in particular, has a round cross-section. Of course, the bore can also have any other cross-section shape. The bore, in particular, has a diameter in the range of 0.01 - 4.00 mm.

[0023] The hole is made in the sheet metal using a drill, drill eroder, punch, water jet drill and / or laser drilling.

[0024] A "through cut" is, in particular, an elongated, continuous opening through the thickness of the sheet. The through cut ends, in particular, in the horizontal direction in the two spaced holes. A through cut can also be a through notch, a through groove, and / or a through slot through the sheet thickness.

[0025] A "sheet metal section adjacent to the continuous cut" is understood to mean, in particular, the area of ​​the sheet metal which, when viewed from above, borders one of the two long sides of the cut.

[0026] "Bending" is understood, in particular, to mean that at least one of the two sheet metal sections adjacent to the continuous cut is bent upwards, forming a hole with a specific shape. By bending the sheet metal section or both sheet metal sections adjacent to the cut, the sheet metal section or sections are bent, in particular, into a specific shape. In this case, the sheet metal section is bent, in particular, simultaneously or sequentially, both horizontally and vertically relative to a horizontal sheet. In particular, the adjacent sheet metal section is bent in such a way that a triangular, semicircular, semi-elliptical, or otherwise curved opening is formed on one side of the sheet and / or perforated sheet. The bending is carried out, for example, using a punch or bending tool in a press or bending machine.Bending can also be done by die bending, roll bending or free bending.

[0027] In a further embodiment of the method, further spaced holes and further continuous cuts are made at different positions of the sheet and then bent to form further holes.

[0028] This allows a perforated sheet to be manufactured with a large number of holes. From a manufacturing perspective, it is advantageous to first drill all holes, then make all cuts, and then bend the adjacent sheet sections at the corresponding through cuts, thus minimizing tool changes.

[0029] When forming a large number of holes, it is particularly advantageous if the holes are evenly distributed across the surface of the sheet, so that different hole pitches and feed rates can be adjusted as required. The smallest dimensions for the hole pitch and feed rate determine, in particular, the maximum open area of ​​the perforated sheet. The open area, as the ratio of the area of ​​the openings on one side of the sheet to the total area of ​​the sheet on that side, is in particular 1.0% to 40.0%, preferably 10.0% to 30.0%. Furthermore, the number of holes in the perforated sheet allows the pressure loss to be adjusted to suit the respective application conditions.

[0030] The "further holes" correspond to the hole defined above, the "further through cuts" correspond to the through cut defined above and the "further holes" correspond to the hole defined above.

[0031] In order to achieve high dimensional accuracy and high surface quality, the holes and / or cut(s) are made using a beam source unit.

[0032] Thus, the holes and / or cuts can be made using water jets and / or laser beams.

[0033] A "beam source unit" is, in particular, a machine for water jet cutting, laser beam fusion cutting, flame cutting and / or plasma fusion cutting.

[0034] In a further embodiment of the method, the holes are drilled at an angle in a range of 40° to 50° to the horizontal alignment of the sheet.

[0035] This advantageously creates inclined hole flanks by drilling the holes relative to a horizontal sheet, and the flow is optimally guided as it passes through the hole, both at the inlet and outlet openings. Furthermore, optimal flow separation can be achieved at the upper opening of the hole, for example, at the upper edge of the bent sheet section.

[0036] An "angle" (also called "drilling angle") refers in particular to a horizontal alignment of the sheet, for example to the bottom or top edge of a lying sheet.

[0037] In order to specifically adjust a stronger flow in the area of ​​the holes, the holes are drilled with a larger drill diameter than the cutting width of the corresponding cut.

[0038] The "cutting width" is in particular the extent of the cut transverse to the longitudinal direction of the cut.

[0039] In a further embodiment of the method, the two spaced-apart bores are made and thus the holes are formed with a specific arrangement over a surface of the sheet, in particular in the form of a spiral and / or segmental arcs.

[0040] By distributing and inserting the paired bores and thus the holes formed in a predetermined arrangement across the surface of the sheet, specific flows through the holes of the manufactured perforated sheet and / or directed flows within a processing device are realized. Furthermore, the perforated sheet can have predefined areas with low and / or high flow, as well as local flows and / or a flow gradient across the surface of the sheet during use.

[0041] In order to achieve an outlet of the flow in a specific direction when using the manufactured perforated sheet, the continuous cut or cuts are made at an angle of 10° to 170°, in particular of 30° to 150°, preferably of 50° to 130° to one or the horizontal orientation of the sheet.

[0042] This allows the continuous cuts and thus the resulting holes to have different and / or identical angles with a specific orientation to the horizontal surface of the sheet, allowing the use of the manufactured perforated sheet to generate specifically directed flows, such as radial flows. Thus, the manufactured holes can open alternately in opposite directions, for example, at an angle of 60° from the horizontal surface of the sheet.

[0043] In a further aspect of the invention, the object is achieved by a perforated sheet which is produced in particular according to a method described above, wherein the perforated sheet has at least one hole and the at least one hole has a bent-up adjacent sheet section on an upper side or underside of the perforated sheet, and the perforated sheet has two bores each introduced at an angle in a range of 30° to 60° to a horizontal alignment of the perforated sheet, forming a start and end region of the at least one hole.

[0044] Thus, a perforated sheet is provided in which the outer corners and / or edges of the hole, which border the solid sheet of the perforated sheet, are designed in such a way that, due to optimal airflow through the corresponding corner and / or edge areas of the hole, the accumulation of bacteria, organic and / or inorganic substances is prevented. Thus, the perforated sheet produced can also be used in hygiene-relevant areas, such as the pharmaceutical and / or food industries.

[0045] In an additional aspect of the invention, the object is achieved by a molded part which is manufactured by joining and / or forming a previously described perforated sheet.

[0046] This allows the molded part to be manufactured, for example, as a flow plate for a fluidized bed system made up of several perforated sheets, or as a perforated sheet formed into a filter element. Consequently, the improved flow through the molded part requires less maintenance and cleaning. In particular, the molded part can also be used in hygiene-relevant areas and / or systems, such as the production of powdered milk for baby food.

[0047] "Joining" refers specifically to a manufacturing technique for connecting perforated sheet metal to itself, for example, to form a cylindrical shape, with one or more other perforated sheets or other components. Joining essentially involves permanently connecting two or more solid bodies with a geometrically defined shape. Joining encompasses, in particular, all process groups defined by DIN 8593. Joining includes, in particular, welding, soldering, gluing, riveting, and / or screwing.

[0048] "Forming" refers, in particular, to a process in which the perforated sheet is deliberately shaped into a different form. The forming itself takes place without removing any material from the perforated sheet. Forming includes, in particular, rolling, open-die forging, drop forging, pressing, deep drawing, and / or bending.

[0049] In a further aspect of the invention, the object is achieved by a processing device, in particular a fluidized bed device, wherein the processing device has a previously described perforated plate and / or a previously described shaped part.

[0050] Consequently, by using the perforated sheet according to the invention and / or the molded part according to the invention, a faster flow and more efficient processing in a processing device can be achieved.

[0051] In addition, the improved flow through the molded part and / or perforated sheet results in a more intensive heat and / or mass exchange during chemical and / or physical processes, so that the chemical and / or physical conversion can be achieved more quickly and / or the corresponding system can be dimensioned smaller.

[0052] A "processing device" (also "processing plant") is, in particular, any device or plant in which a substance, semi-finished product, or product is chemically and / or physically modified and thus processed. A processing device can, for example, be a filter, screening, centrifuge, dewatering, separation, drying, and / or cooling system.

[0053] The invention will be explained in more detail below with reference to exemplary embodiments. Figure 1 is a highly schematic representation of a sheet in plan view with holes and continuous sections, Figure 2 is a highly schematic sectional representation of a perforated sheet in side view, and Figure 3 is a highly schematic sectional representation of a section of a perforated sheet with a hole in longitudinal section.

[0054] A sheet 103 has a bottom side 123, a top side 125 and a sheet thickness 105. To produce a perforated sheet 101, the sheet 103 (shown in Figure 1 A plurality of bores are distributed across the sheet metal (in plan view) using a drill, wherein a first bore 107 is arranged at a defined distance from a second bore 109. The first bore 107 and the second bore 109 are drilled at a drilling angle 111 of 45° to the lower edge of the sheet metal 103 and pass completely through a sheet thickness 105 of the sheet metal 103. The first bore 107 and the second bore 109 have a round cross-section.

[0055] Subsequently, the spaced-apart first bore 107 and the second bore 109 are each connected by means of a cut 113, each cut 113 passing completely through the sheet thickness 105. All cuts 113 are made in the sheet 103 using a laser beam cutter. All first bores 107 and all second bores 109 have a bore diameter of 3.0 mm, while all cuts 113 have a cutting width of 1.5 mm.

[0056] After all cuts 113 have been made, all sheet metal sections 127 lying on the same long side of the cuts 113 are bent upwards one after the other by the action of a punch from the underside 123, so that a hole 115 is created with a lower opening 119 and an upper opening 121 aligned horizontally with respect to the orientation of the sheet 103. As a result, on the upper side 125 of the sheet 103 (see Figure 3) a structured surface and a smooth underside with a flush lower opening 119 on the underside 123 of the sheet 103. Further holes are formed accordingly until the perforated sheet 101 with the desired number of holes 115 is obtained.

[0057] Due to the drilling angle 111 of 45°, an oblique hole edge 117 is formed at each hole 115, which, due to its oblique design, causes an optimal flow separation when a fluid passes from the lower opening 119 to the upper opening 121 of each hole 115.

[0058] The manufactured perforated plate 101 is used as a flow plate for gas distribution in a fluidized bed system (not shown) for drying milk powder. The drying gas is supplied on the underside 123 of the perforated plate 101 and flows out through the respective hole 115 of the perforated plate 101 essentially horizontally from the respective upper opening 121 of the hole 115. The design of the perforated plate 101 with the upper curved sheet sections 127 and the horizontally aligned upper openings 121 of the holes 115 prevents, on the one hand, direct entry and sedimentation of milk powder vertically from above into the respective hole 115. On the other hand, the hole flanks defined by the bores 107 and 109 prevent the accumulation of bacteria and / or milk powder. Consequently, the perforated plate 101 according to the invention prevents hygienically relevant contamination. List of reference symbols

[0059] 101 Perforated sheet 103 Sheet 105 Sheet thickness 107 First hole 109 Second hole 111 Drill angle 113 Cut 115 Hole 117 Hole edge 119 Lower opening 121 Upper opening 123 Bottom of sheet 125 Top of sheet 127 Sheet section

Claims

1. A method for producing a perforated plate (101), wherein the produced perforated plate has at least one hole (115), said method having the following steps - making two spaced-apart bores (107, 109) in a plate (103), wherein the bores are formed continuously through a thickness (105) of the plate, - making a continuous cut (113) between the two spaced-apart bores in the plate, and - bending up a plate portion (127) adjacent to the continuous cut, in such a way that a hole is formed, characterised in that the bores (107, 109) are formed at an angle (111) in a range of from 30° to 60° to a horizontal alignment of the plate.

2. The method according to claim 1, characterised in that further spaced-apart bores and further continuous cuts are made at different positions of the plate and the plate is bent up to form further holes.

3. The method according to any one of the preceding claims, characterised in that the bores and / or the cut or the cuts are / is made by means of a beam source unit.

4. The method according to any one of the preceding claims, characterised in that the bores are made at the angle (111) in a range of from 40° to 50° to the horizontal alignment of the plate.

5. The method according to any one of the preceding claims, characterised in that the bores are each made with a larger bore diameter than a cut width of the associated cut.

6. The method according to any one of claims 1 to 5, characterised in that each two spaced-apart bores are made, and therefore the holes are formed, with a specific arrangement over an area of the plate, in particular in the form of a spiral and / or segment arcs.

7. The method according to any one of the preceding claims, characterised in that the continuous cut or the continuous cuts is / are made at an angle of from 10° to 170°, in particular from 30° to 150°, preferably from 50° to 130° to a or the horizontal alignment of the plate.

8. A perforated plate (101), wherein the perforated plate has at least one hole (115) and the at least one hole has a bent-up, adjacent plate portion on an upper side or underside of the perforated plate, characterised in that each two bores (107, 109) made at an angle (11) in a range of from 30° to 60° to a horizontal alignment of the perforated plate (101) form a start and end region of the at least one hole.

9. A moulded part which is manufactured by joining and / or reshaping a perforated plate (101) according to claim 8, so that the moulded part comprises the perforated plate (101).

10. A preparation device, in particular a fluidised bed device, wherein the preparation device comprises a perforated plate (101) according to claim 8 and / or a moulded part according to claim 9.