Machine tool for machining a diaphragm seal

Abstract

Machine tool (100) for machining, in particular for repairing, a diaphragm seal (50) of a flange (51), which in the assembled state has a diaphragm plate (52) that is fixed to a sealing surface of the flange (51) by means of a weld (53), with a frame (54) comprising a stationary part (55) and a movable part (56), wherein the stationary part (55) is designed for the direct or indirect mounting of the machine tool (100) on the flange (51) and a tool carrier (57) is arranged on the movable part (56), characterized in that the tool carrier (57) is designed as a tool adapter (571) for receiving different tools (58) and the frame (54) has several axes (591, 592, 593, 594) that define a machining area (60), each designed as a linear guide (61) and via several movable carriages (621, 622,623) are aligned and connected to each other in such a way that the tool adapter (571) can be moved along any three-dimensional trajectory within the machining space (60) when mounted on the machine tool (100).

Description

[0001] The invention relates to a machine tool for machining, in particular for repairing, a diaphragm seal of a flange, which in the assembled state has a diaphragm plate that is fixed to a sealing surface of the flange by means of a weld, with a frame comprising a stationary part and a movable part, wherein the stationary part is designed for the indirect or direct mounting of the machine tool on the flange and a tool carrier is arranged on the movable part.

[0002] Diaphragm gaskets are known from the petrochemical industry and are used to seal containers such as heat exchangers. A diaphragm gasket essentially consists of a metallic diaphragm plate welded around its entire circumference to a sealing surface of a flange. Typically, diaphragm plates of this type have a diameter of approximately 1.4 m to 2.2 m and generally weigh more than 100 kg.

[0003] During overhauls and / or operational shutdowns of the system, for example, for cleaning the inside of the tank, these diaphragm plates must be removed from the tank. To do this, the connecting weld must first be completely removed. The weld can be a fillet weld. If the diaphragm plate rests, at least partially, in a recess (i.e., within a sealing-face-side depression of the flange), the weld can also be an I-joint. Furthermore, in some cases, after removing the diaphragm plate, the sealing surface and / or the bearing surface on the tank must be reworked. This may include leveling, removing weld metal residue, and restoring the geometry. If the sealing surface is too thin or damaged, for example, due to cracks or previous machining, a cladding weld must be applied before reworking the sealing surface.

[0004] The Fig. 1a, b show in a top view ( Fig. 1a) and a side view ( Fig. 1b) A mobile machine 10, known in the art, is arranged along the cross-sectional plane AA and is used to remove the weld seam 11 of a diaphragm seal 12 in a conventional manner. The machine 10 has a stationary part 13 and a rotating part 14. The machine 10 is mounted on studs 16 via a plurality of alignment elements 15. These studs are arranged on the flange side, encircle the diaphragm plate 17, and are configured for alignment in the direction of arrow P1. If the studs 16 are already removed from the flange 18, adapters (not shown) are known which are screwed into the threaded studs 17. The alignment of the machine 10 is preferably carried out using a dial gauge on the component, i.e., either on the flange 18 or on the diaphragm plate 17.The rotating part 14 has a tool holder 19 with a turning tool 20 and is guided by a drive unit 21 along the stationary part 13 in a ring-shaped motion in the direction of arrow P2 around the diaphragm plate 17. The turning tool 20 engages with the weld seam 11 and is operated with a continuous feed in the container direction P3, so that the weld seam 11 is completely removed.

[0005] After the weld seam 11 has been completely removed, this first machine 10 is disassembled in order to remove the diaphragm plate 17. A second machine (not shown) must then be installed to machine the sealing surface of the flange 18.

[0006] Should it be necessary to repair the sealing surface, partial or complete manual welding will be carried out before the machine-based sealing surface processing can be carried out using the second machine.

[0007] The machines known according to the state of the art have proven to be disadvantageous in several respects.

[0008] The alignment of the first and second machines can only be performed manually within the respective tolerances of the measuring instruments, machine, and mounting to the tank-side sealing surface and / or the diaphragm plate. Therefore, excessive material removal typically occurs on both the tank-side sealing surface and the diaphragm plate, which must be reduced due to the weld penetration. For this reason, tank manufacturers generally limit the maximum number of such machining operations to 2-3. After that, either the sealing surface must be completely resurfaced or the tank flange replaced, which involves significant material and assembly costs.

[0009] Conventional machines use turning tools that rotate continuously along the stationary part and feed continuously in the direction of the vessel to remove material. Material is removed until the diaphragm plate falls off. It is possible that residual pressure or product remains in the vessel, or that the diaphragm plate has residual stress due to the welding process, both of which can cause it to fall or pop out suddenly. The machine operator is typically positioned directly in front of the machine and is regularly exposed to a potential risk of injury due to the unpredictable fall of the diaphragm plate. Even without residual pressure within the heat exchanger, a risk of injury remains when the diaphragm plate falls and is removed by a conventional machine.

[0010] If the diaphragm plate falls, the machine must be stopped manually as quickly as possible to prevent the plate from whipping around or becoming wedged between the heat exchanger and the machine. The falling of diaphragm plates, some weighing over 100 kg, is always a hazard, especially since some machining operations are carried out at heights of up to 20 m.

[0011] To perform the respective processing operation, the machines must be clamped with their stationary part in front of or against the container. The machines are operated manually, often while the machine is running. Even if the machine is stopped for each adjustment, there is a risk of injury if the operator manually intervenes in the rotating system.

[0012] Typically, at least some of the studs around the diaphragm plate must be removed for machining. Usually, some of the stud threads are also damaged and require time-consuming and labor-intensive repair using a different method, because the first and second machines cannot perform this maintenance.

[0013] If the diaphragm plate is additionally welded with an I-groove, the machining time with a conventional machine increases considerably due to the longer tool length, and the wear on turning tools or indexable inserts increases significantly. To achieve sufficient stability for plunge cutting, a relatively wide cut, usually up to 10 mm, is required, which is associated with a corresponding loss of material.

[0014] The machining time using a conventional machine varies considerably depending on the specific site conditions, the operator's experience, and the diameter of the diaphragm plate. Including machine assembly and alignment, machining a diaphragm plate with a diameter of 1.5 m to 2 m takes approximately 12 hours. The diaphragm plate then needs to be removed, which, with conventional machining, requires disassembling the lathe. After removing the diaphragm plate, a second machine must be assembled to machine the tank sealing surface, which typically takes another 10 to 12 hours. Manual assembly of the second machine introduces further inaccuracies in alignment, effectively doubling the overall error caused by manual measurement.

[0015] The conventional machine can only be aligned in one plane at the flange or diaphragm plate. The flange or diaphragm plate may be uneven. Furthermore, the diaphragm plate may be welded at an angle to the sealing surface or cladding. To minimize material removal from the sealing surface, a process of "probing" the alignment is necessary in these cases, requiring the conventional machine to be re-aligned multiple times in different machining planes. Directly accounting for potential unevenness during machine alignment is not possible.

[0016] Should it be necessary to re-weld the tank sealing surface, for example by cladding, the welders face considerable time pressure coupled with high quality requirements, because these rework operations are generally decided upon based on a specific finding and cannot be planned in advance. Before each manual cladding process, the machine for processing the sealing surface must be disassembled and then reassembled. Manual welding, which sometimes requires working in a constrained position, frequently results in porosity. These defects may only become visible after subsequent machining, necessitating a repetition of the process.

[0017] The weld thickness required cannot be reliably estimated, measured, and / or maintained by the welder. The resulting uneven weld overlay makes subsequent machining challenging and time-consuming. Furthermore, the interrupted cut causes increased wear on the machining tools. Insufficient weld thickness may only become apparent after further machining.

[0018] Overall, the repair of diaphragm seals, especially the removal of a diaphragm plate and the preparation of a reworked flange-side sealing surface for the installation of a new or reworked diaphragm plate, is disadvantageous using conventional machinery. In particular, conventional machining is labor-intensive, prone to wear, and involves a significant risk of injury.

[0019] Based on this, the object of the present invention is to propose a machine tool for machining, and in particular for repairing, diaphragm seals, which overcomes the aforementioned disadvantages. The machining process should specifically include the removal of a diaphragm seal and the preparation of a reworked flange-side sealing surface for the installation of a new or reworked diaphragm plate. In particular, the machine tool should allow the repair of a diaphragm seal with minimal effort, minimal wear of the tools used, and a low risk of injury.

[0020] This task is solved by the machine tool according to claim 1.

[0021] The starting point of the invention is a machine tool for machining, in particular for repairing, a diaphragm seal of a flange, which in the assembled state has a diaphragm plate that is fixed to a sealing surface of the flange by means of a weld, with a frame comprising a stationary part and a movable part, wherein the stationary part is designed for the indirect or direct mounting of the machine tool on the flange and a tool carrier is arranged on the movable part.

[0022] Based on this, the invention provides that the tool carrier is designed as a tool adapter for receiving different tools and that the frame has several axes that span a machining space, each designed as a linear guide and are aligned and connected to each other via several movable slides in such a way that the tool adapter can be moved within the machining space along any three-dimensional trajectory when mounted on the machine tool.

[0023] This proposal describes a machine tool designed for machining, and in particular repairing, diaphragm seals, and which overcomes the aforementioned disadvantages. The machining capabilities include, in particular, the removal of a diaphragm seal and the preparation of a reworked flange-side sealing surface for the installation of a new or reworked diaphragm plate. Specifically, the machine tool allows for the repair of a diaphragm seal with minimal labor, low tool wear, and a low risk of injury.

[0024] A particular advantage of the machine tool according to the invention for removing the diaphragm plate is that the weld contours can be machined segment by segment. Thus, at the beginning of the machining process, the weld can be removed along a first section. The plate can then be secured against falling, for example, by clamping the diaphragm plate using a chain hoist, a wedge, a hydraulic ram, or another releasable fastening device, before the remainder of the weld is removed and the diaphragm plate is completely detached from the flange. In this way, even after the weld has been completely removed, the diaphragm plate cannot unintentionally detach and fall, and therefore poses no safety risk to the operator.

[0025] Advantageous embodiments of the invention are specified below and in the dependent claims.

[0026] According to an advantageous embodiment of the invention, the frame has at least three axes, which are preferably arranged parallel to the axes of a Cartesian coordinate system, the xy-plane of which, in the assembled state of the machine tool, is preferably aligned parallel to the sealing surface of the flange. The perpendicular arrangement of the axes to each other results in particularly simple control of the individual slides, so that the tool adapter is moved along the desired trajectory.

[0027] The slides preferably each have separate linear drives. Such linear drives are preferably designed as electric motors that allow precise movement of the respective slides.

[0028] A control unit is preferably provided for controlling the linear drives, which is in particular designed as a CNC control unit.

[0029] According to an advantageous further development of the invention, it is provided that • the stationary part has the first axis on which the first slide is arranged to move, • the first slide carries the second axis on which the second slide is arranged to move, and • the second slide carries the third axis, on which the third slide is arranged to move and which carries the tool adapter.

[0030] The stationary part preferably has a fourth axis, arranged parallel to the first axis and designed to guide the movable part of the frame, wherein the first axis and the fourth axis are preferably connected to each other by two spaced-apart struts. The stationary part is thus rectangular, in particular square, and therefore allows for particularly simple and stable mounting on the flange.

[0031] The machine tool preferably has a 3D probe that is set up and aligned to scan the diaphragm seal and / or the flange surface and / or the sealing surface of the flange. The acquired data provides information about the three-dimensional position of the diaphragm seal, in particular its path, thickness, and the position of the weld to be removed. This allows the machine tool to be precisely aligned with the diaphragm seal and / or the sealing surface, thus significantly reducing the risk of excessive material removal due to inaccurate setup. Advantageously, this also allows for the precise removal of weld geometries that deviate from a circular path.

[0032] Preferably, a frame is provided for the indirect mounting of the machine tool to the flange, which can be clamped to the flange at least indirectly by means of several radially movable pins. The frame essentially consists of a rectangular plate with a round cutout, which, in the mounted state, is completely radially spaced from the flange along its inner circumference.

[0033] When the machine tool is assembled, at least the diaphragm plate, preferably the entire surface of the flange, is located within the machining area. This ensures that all necessary machining operations can be carried out using the machine tool.

[0034] Different tools are required for different machining operations, which must be operated at different speeds depending on the requirements. According to an advantageous embodiment of the invention, the spindle speed of the tool holder is therefore variable and preferably adjustable between 0.1 rpm and 24,000 rpm, more preferably between 0.1 rpm and 7,200 rpm. The tool adapter preferably has a gearbox for adjusting the spindle speed. It is preferably provided that the control unit, in particular the CNC control unit, is configured to regulate the spindle speed.

[0035] The machine tool can preferably be connected to a control unit wirelessly or via cable. The possibility of remote control of the machining process ensures that the operator can work at a safe distance.

[0036] In a further advantageous embodiment, the tools that can be received by the tool adapter are designed as a milling spindle and / or a welding device. The milling spindle is preferably designed to receive a milling head and / or a thread milling cutter, and the welding device is preferably designed for weld overlay. The milling spindle can receive different milling heads designed for different machining operations. For example, the milling spindle can receive milling heads designed for removing a fillet weld. The milling spindle can also receive milling heads designed for removing an I-groove. The ability to change tools allows, in particular, the axial reworking of damaged threads and the re-milling of contact surfaces for nuts at a precise 90° angle to the axis.This eliminates the previous need to dismantle the conventional weld removal machine and assemble another machine, potentially requiring error-prone readjustment. With automated cladding of the sealing surface using the machine tool, interfaces between different trades are eliminated, the time required for cladding is reduced, the quality of the cladding is increased, the specified minimum thickness is precisely maintained, and the time-consuming and error-prone dismantling and reassembly of the machine is avoided.

[0037] The frame of the machine tool preferably consists of aluminum profiles, which on the one hand provide sufficient stability and on the other hand have a low mass, so that the machine tool can be easily assembled. The maximum current requirement for operating the machine tool is preferably 63 A.

[0038] A specific embodiment of the invention is described below with reference to the figures. These show: Fig. 1a, b a machine according to the state of the art; Fig. 2a, b a machine tool in a top view and a cross-sectional view along the cross-sectional plane BB.

[0039] The machine tool 100 is designed for machining, in particular for repairing, a diaphragm seal 50 of a flange 51, which in its assembled state has a diaphragm plate 52 that is fixed to a sealing surface of the flange 51 by means of a weld 53. The machine tool 100 has a frame 54 comprising a stationary part 55 and a movable part 56, wherein the stationary part 54 is designed for direct or indirect mounting of the machine tool 100 to the flange 51, and a tool holder 57 is arranged on the movable part 56.The tool carrier 57 is designed as a tool adapter 571 for receiving different tools 58, and the frame 54 has several axes 591, 592, 593, 594 which define a machining area 60. Each axe is designed as a linear guide 61 and is aligned and connected to one another via several movable slides 621, 622, 623 such that the tool adapter 571, when mounted on the machine tool 100, can be moved within the machining area 60 along any three-dimensional trajectory. The frame 54 has the four axes 591, 592, 593, 594, which are each arranged parallel to the axes of a Cartesian coordinate system K, the xy-plane of which is aligned parallel to the sealing surface of the flange 51. The carriages 621, 622, 623 each have separate linear drives 63, so that the carriages can be moved in the directions of arrows P4, P5, P6.A control unit 64 is provided for controlling the linear drives 63; in the illustrated embodiment, this unit is configured as a CNC control unit 641. The stationary part 55 has the first axis 591, on which the first slide 621 is movably arranged. The first slide 621 carries the second axis 592, on which the second slide 622 is movably arranged. The second slide 622 carries the third axis 593, on which the third slide 623 is movably arranged and which carries the tool adapter 571.

[0040] The stationary part 55 has a fourth axis 594, which is arranged parallel to the first axis 591 and is designed to guide the movable part 56 of the frame 54. The first axis 591 and the fourth axis 594 are connected to each other via two spaced-apart struts 65.

[0041] The machine tool 100 has a 3D probe 66 which is set up and aligned to probe the diaphragm seal 50 and the surface of the flange 51 and the sealing surface of the flange 51.

[0042] For the indirect mounting of the machine tool 100 on the flange, a frame 67 is provided which can be clamped directly to the flange 51 by means of several radially movable punches 68.

[0043] In the assembled state of the machine tool 100, the diaphragm plate 52 and the entire surface of the flange 51 are arranged within the machining area 60.

[0044] The spindle speed of the tool carrier 57 is variable and can be set between 0.1 rpm and 24,000 rpm.

[0045] The tool adapter 571 has a gearbox 69 for adjusting the spindle speed.

[0046] The control unit 64, which is designed here as CNC control unit 641, is also set up to control the spindle speed.

[0047] The machine tool 100 is wirelessly connected to a control unit 70.

[0048] The tools 58, which can be received by the tool adapter 571, are designed as a milling spindle 581 or as a welding device, wherein the milling spindle 581 is designed to receive a milling head and a thread milling cutter and the welding device is designed for surfacing welding. Reference sign 10 mobile machines 11 weld seam 12 Diaphragm seal 13 stationary part 14 rotating part 15 aligns element 16 studs 17 Diaphragm plate 18 flange 19 tool holders 20 turning tools 21 Drive unit Pn Arrow direction (n = 1,..., 3) 100 machine tools 50 Diaphragm seal 51 flange 52 Diaphragm plate 53 weld seam 54 frame 55 stationary part 56 moving part 57 tool carriers 571 Tool adapter 58 tools 581 Milling spindle 591 Axle 592 axle 593 axle 594 axle 60 processing room 61 Linear guide 621 sleds 622 sleds 623 sleds 63 Linear drive 64 Control unit 641 CNC control unit 65 strut 66 3D buttons 67 frames 68 stamps 69 gearboxes 70 Control unit K coordinate system PM Arrow direction (m = 4,..., 6)

Claims

[1] Machine tool (100) for machining, in particular for repairing, a diaphragm seal (50) of a flange (51), which in the assembled state has a diaphragm plate (52) which is fixed to a sealing surface of the flange (51) by means of a weld (53), with a frame (54) comprising a stationary part (55) and a movable part (56), wherein the stationary part (55) is designed for the direct or indirect mounting of the machine tool (100) on the flange (51) and a tool holder (57) is arranged on the movable part (56), characterized by, that the tool carrier (57) is designed as a tool adapter (571) for receiving different tools (58) and the frame (54) has several axes (591, 592, 593, 594) that span a machining space (60), each designed as a linear guide (61) and are aligned and connected to each other via several movable slides (621, 622, 623) such that the tool adapter (571) can be moved within the machining space (60) along any three-dimensional trajectory when mounted on the machine tool (100). [2] Machine tool (100) according to claim 1, wherein the frame (54) has at least three axes (591, 592, 593) which are preferably arranged parallel to the axes (x, y, z) of a Cartesian coordinate system (K) whose xy-plane in the assembled state of the machine tool (100) is preferably aligned parallel to the sealing surface of the flange (51). [3] Machine tool (100) according to one of the preceding claims, wherein the slides (621, 622, 623) each have separate linear drives (63). [4] Machine tool (100) according to claim 3, wherein a control unit (64), in particular a CNC control unit (641), is provided for controlling the linear drives (63). [5] Machine tool (100) according to one of the preceding claims, wherein the stationary part (55) has the first axis (591) on which the first slide (621) is movably arranged, the first slide (621) carries the second axis (592) on which the second slide (622) is movably arranged, and the second slide (622) carries the third axis (593) on which the third slide (623) is movably arranged and which carries the tool adapter (571). [6] Machine tool (100) according to one of the preceding claims, wherein the stationary part (55) has a fourth axis (594) which is arranged parallel to the first axis (591) and is designed to guide the movable part (56) of the frame (54), wherein the first axis (591) and the fourth axis (594) are preferably connected to each other via two spaced-apart struts (65). [7] Machine tool (100) according to one of the preceding claims, wherein the machine tool (100) has a 3-D probe (66) which is set up and aligned to probe the diaphragm seal (50) and / or the surface of the bottle (51) and / or the sealing surface of the flange (51). [8] Machine tool (100) according to one of the preceding claims, wherein a frame (67) is provided for the indirect mounting of the machine tool (100) on the flange (51), which can be clamped at least indirectly on the flange (51) by means of several radially movable punches (68). [9] Machine tool (100) according to one of the preceding claims, wherein in the assembled state of the machine tool (100) at least the diaphragm plate (52), preferably the entire surface of the flange (51), is arranged within the machining space (60). [10] Machine tool (100) according to one of the preceding claims, wherein the spindle speed of the tool carrier (57) is variable and preferably adjustable between 0.1 rpm and 24,000 rpm, preferably between 0.1 rpm and 7,200 rpm. [11] Machine tool (100) according to one of the preceding claims, wherein the tool adapter (571) has a gearbox (69) for adjusting the spindle speed. [12] Machine tool (100) according to one of claims 10 or 11, wherein the control unit (64), in particular the CNC control unit (641), is configured to control the spindle speed. [13] Machine tool (100) according to one of the preceding claims, wherein the machine tool (100) can be connected wirelessly or via cable to a control device (70). [14] Machine tool (100) according to one of the preceding claims, wherein the tools (58) which can be received by the tool adapter (571) are designed as a milling spindle (581) and / or as a welding device, wherein the milling spindle (581) is preferably designed to receive a milling head and / or a thread milling cutter and the welding device is preferably designed for surfacing welding.

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