Cylindrical stack of fixing device rings for turbine blade surface treatment

Abstract

The present invention relates to a segment of a fixing device, the fixing device comprising a plurality of such segments arranged to form a fixing device ring, said segments including a carrier segment and a cover segment.

Description

Technical Field

[0001] The present invention relates to a support for multiple substrates to be treated in a surface treatment process. Background Technology

[0002] A whole range of different processes for polishing surface layers on workpieces are known, depending on the application, material, and structure of the surface layer. The purpose of polishing, in addition to simply removing material from the surface, typically includes reducing surface roughness. This may be desired, for example, for purely aesthetic reasons (e.g., to produce a glossy surface), or it may be required due to technical needs, such as reducing the coefficient of friction, minimizing the adhesion or inclusion of impurity particles to maintain the desired surface porosity, or preventing surface contamination. This can thus improve aerodynamics, increase efficiency, and consequently reduce kerosene consumption. In the art, the roughness of solid surfaces is typically characterized by various roughness measurement parameters, which can be found in the relevant technical literature.

[0003] One of these roughness measurement parameters is the so-called "average roughness value Ra", which is a measure of surface roughness as the average deviation of the absolute amount of roughness profile relative to the centerline within a preset measurement path, and is given in micrometers (μm) according to the degree of roughness.

[0004] As already mentioned, different methods are used to reduce surface roughness depending on the application. For example, turbine blades of aircraft turbines or land-based gas turbines used to generate electricity have, for example, metallic alloy layers, particularly MCrAlY layers, where M represents a metal such as nickel (Ni), cobalt (Co), or iron (Fe), and CrAlY (chromium, aluminum, yttrium) represents a superalloy very common for the aforementioned and other purposes. These layers can be applied, for example, in a vacuum chamber at a thickness between 50 μm and 250 μm, with a surface roughness Ra typically reaching about 6 μm to 12 μm. Furthermore, an insulating layer is usually required for the aforementioned MCrAlY layer, which is often referred to by those skilled in the art as a TBC coating (thermal barrier coating). This TBC coating can be fabricated, for example, on a zirconium dioxide (ZrO2) substrate—in typical examples—the insulation layer can be approximately 100 μm to 500 μm thick, and in special cases greater than 1 mm, and the insulation layer essentially comprises 92% ZrO2 and 8% yttrium oxide (Y2O3) for stabilization. The particle size constituting the layer can be, for example, between 45 μm and 125 μm, and the porosity of the insulation layer typically reaches between 5% and 20%. Typical values ​​for the roughness of the TBC coating are found to be in the range of 9 μm to 16 μm. It should be noted at this point that the above parameters of the layers and their chemical composition can differ significantly from the examples cited above in specific cases.

[0005] However, in general, other coatings (such as TiAlN or AlTiN) can be used as alternatives.

[0006] However, the surface roughness exhibited by these layers after application to the workpiece is often unacceptable and must be reduced, for example, by polishing. In practically important examples for turbine blades in land-based turbines, a maximum surface roughness Ra of 0.3 μm is required for aerospace applications, while a maximum Ra of 0.8 μm is required for power generation turbines.

[0007] For MCrAlY layers, or generally for metallic or metal alloy surfaces, different methods can be used, such as conventional abrasive blasting (e.g., using fine corundum), shot peening (using hard steel, stainless steel, or ceramic abrasive), or cut-wire peening, to achieve the desired surface roughness.

[0008] To obtain the highest possible surface quality, i.e., minimal and / or uniform roughness of the material surface, various methods are available for vibratory polishing in combination with polishing elements that have abrasive action.

[0009] However, only the vibratory polishing method mentioned last is used for polishing most TBC layers because it treats the surface gently enough during the polishing process to avoid damage in the form of micro-tears, surface area detachment, or similar damage in porous TBC coatings.

[0010] Two variants of polishing equipment are widely used for vibratory polishing: the so-called circular vibrator and the disc vibrator.

[0011] A disc vibrator is a device that essentially comprises a polishing container containing corresponding polishing elements, which are vibrated by a suitable means. In its simplest form, the workpiece to be processed is placed in the polishing container, allowing it to be polished by the polishing elements, which, under vibration, behave as a whole, similar to a viscous liquid.

[0012] Separating slides can be provided to prevent adjacent workpieces from touching or damaging each other in the polishing container, and also to provide external attachment for the workpieces. Covering specific surface areas of the workpiece with a covering can also provide further protection, allowing only a portion of the workpiece to be polished, and / or, for example, protecting edges in a hazardous condition.

[0013] These devices known in the prior art have drawbacks that lead to unsatisfactory results, especially when polishing non-rotationally symmetric workpieces and / or workpieces with porous surfaces (such as turbine blades with TBC coatings).

[0014] For example, unacceptably high mechanical strain can act on externally clamped workpieces being processed in a disc vibrator, potentially leading to damage to the workpiece and / or the surface to be processed (especially porous and / or fragile surfaces). If, according to existing technology, the workpiece to be polished is placed directly into the polishing container of the disc vibrator without external securing, there is a risk that the workpiece may come into direct contact with the walls of the disc vibrator or any existing partition rails and / or adjacent workpieces, thus failing to prevent damage to the workpiece or sensitive areas of the workpiece surface, especially at the edges. A particular risk exists, for example, when a distance of less than two polishing elements is used between the workpiece surface and the adjacent boundary wall, causing the polishing element to become stuck between the workpiece surface and the adjacent boundary wall, resulting in large point strain on the workpiece surface.

[0015] Admittedly, damage of the aforementioned types can be reduced by properly covering surface areas in a hazardous state. However, this is only feasible for surface areas that do not need to be polished. Furthermore, this method is very complex in practice because in each case, it is usually necessary to protect more than one surface area separately by proper covering, which is associated with complex installation or removal of the corresponding components and is therefore inefficient from an economic standpoint. Another significant drawback is that, especially for non-rotationally symmetric workpieces (e.g., turbine blades for land-based applications or aircraft turbine engines), known methods result in insufficient surface roughness and / or, in particular, uneven polished areas—areas with uneven roughness on the workpiece surface. Due to the asymmetrical mass distribution of, for example, turbine blades, the turbine blades will rotate unevenly only among the polishing elements in the polishing container, and during polishing, the surfaces of the turbine blades with different orientations are subjected to polishing elements with different polishing pressures. This ultimately results in different areas of the surface having different surface roughness, and causes insufficiently high roughness to be achieved at certain surfaces of the turbine blades. The above also applies to another aspect of polishing methods where the workpiece is externally secured. The drawbacks described above not only occur in the polishing of turbine blades (to which these problems are explained by example), but also generally occur in vibratory polishing, especially for non-rotationally symmetric workpieces.

[0016] To at least partially overcome these drawbacks, Tanner's US6817051 discloses a vibratory polishing apparatus for workpieces with porous surface coatings. The vibratory polishing apparatus includes a polishing container and a guide device disposed in the container for guiding and holding the workpiece in the polishing container. The guide device has first and second guide members spaced apart by at least one spacer and a retainer for positioning and holding the workpiece between the guide members. The guide device is formed and disposed in the polishing container such that it is free to move, free to rotate, and can be positioned in any position relative to the polishing container while preventing the workpiece from contacting the polishing container during polishing.

[0017] This is an excellent solution for achieving a smooth turbine blade surface without damaging the edges. However, this solution has two main problems:

[0018] i) Generally, many of these turbine blades require polishing. A significant amount of manual work is required to secure the blades to the guide unit. This is time-consuming and makes the entire process economically unattractive.

[0019] ii) The fact that the guiding device is formed and set up in a way that allows it to move freely, rotate freely and be in any position relative to the polishing container makes the polishing process inefficient because vibrations are only transmitted to the blades indirectly. Summary of the Invention

[0020] Therefore, the present invention relates to a surface treatment apparatus, and more particularly to a surface polishing apparatus that at least partially overcomes the above-mentioned problems.

[0021] This invention follows several principles:

[0022] -Using a fixing device that is directly connected to the container, the vibration of the container is transmitted directly to the fixing device.

[0023] -Using a fixing device in which multiple substrates can be placed such that they are in a plane and radially oriented, with one end facing the center and the other end extending radially away from the center, all substrates being equidistant from the center, forming a fixing device ring-

[0024] - The fixing rings are designed to allow multiple fixing rings to be stacked in layers, with the centers of all the fixing rings in the stack on an axis that forms a central axis. The stacking of the fixing rings produces a cylindrical stack.

[0025] According to a preferred embodiment of the invention, the fixing device ring is formed from a detachable segment.

[0026] According to another preferred embodiment, the outer surface of the cylindrical stack is closed, thereby covering the outer end of the substrate to be polished.

[0027] According to another preferred embodiment, the inner end of the substrate to be polished is covered by an inner ring provided by a fixing device ring.

[0028] According to another preferred embodiment, the outer segment includes a lower insertion base formed by a spacer segment, and / or the cover segment includes an upper insertion base formed by a spacer segment to retain and shield the base of the turbine blades mounted therebetween.

[0029] According to another preferred embodiment, the inner segment or ring has a radial extension formed to abut against the tip of the turbine blade for protection. Preferably, the radial extension has a base segment connecting the extension to the inner ring and a tip segment formed to match the shape and curvature of the tip of the turbine blade mounted in the segment, as an extension of the turbine blade.

[0030] According to another preferred embodiment, the segment includes an outer segment disposed radially outside the outer segment, wherein the profile of the outer segment is designed such that the base of a turbine blade can be placed thereon, the blade extending radially outward and radially inward. The inner segment is configured to shield the tip of the inwardly extending turbine blade, and the outer segment is configured to shield the tip of the outwardly extending turbine blade. Optionally, the outer segment, the inner segment, or both may have radial extensions formed to abut against the tip of the turbine blade for protection.

[0031] According to another preferred embodiment, the segment is made of thermoplastic polyurethane (TPU) material and / or derivatives.

[0032] According to one aspect of the invention, the cylindrical stack includes a bottom ring, at least one retaining ring, and a closing ring. In a preferred embodiment, the bottom ring includes at least two shafts extending vertically parallel to a central axis, and said shafts are used to secure the bottom ring and the closing ring together, thereby firmly clamping said at least one ring. Where said at least one ring is composed of separable segments, it is highly preferred that each segment has at least two shafts passing through corresponding holes in the segment, thereby holding these segments in place within the ring. Attached Figure Description

[0033] The invention will now be described in detail with reference to embodiments and the accompanying drawings.

[0034] Figure 1 A fixing device ring according to the invention is shown;

[0035] Figure 2 The disassembled sections are shown, wherein several sections are placed together to form a retaining device ring according to the invention;

[0036] Figure 3 The disassembled section is shown according to a second embodiment of the invention, similar to... Figure 2 The section shown;

[0037] Figure 4 The assembled basis is shown Figure 3 Top view of the section;

[0038] Figure 5 The disassembled section is shown according to a third embodiment of the invention, similar to that in Figures 2 to 5 The section shown;

[0039] Figure 6 Showing the arrangement to be based on Figure 2 , Figure 3 or Figure 6The turbine blades in the fixed device ring have an assembled arrangement and a disassembled arrangement, the turbine blades having a mounting shoe arrangement.

[0040] Figure 7 The disassembled segment arrangement structure according to a fourth embodiment of the present invention is shown;

[0041] Figure 8 A cross-sectional view is shown through the assembled cylindrical stack according to the invention. Detailed Implementation

[0042] Turbine blades have a base and a blade section at the top. The end of the blade section furthest from the base is usually referred to as the blade tip.

[0043] Figure 1 A fixing ring 101 according to the invention is shown, which is composed of seven segments 103, 105, 107, 109, 111, 113, and 115. Turbine blades (shown in dashed lines) are placed in these segments, and these blades are oriented such that the base is furthest from the center of the ring and the blade tip is closest to the center of the ring. The base is covered by the outer ring of the fixing ring, and the blade tip is covered by the inner ring. The rest of the blade portion can be freely accessed from above and below. Figure 1 The figure shows a retaining ring with only partial mounting of turbine blades, specifically only sections 103 and 105. The figure also shows guide lines from the center of the ring to some of the turbine blades, which illustrate the radial orientation of the turbine blades.

[0044] Figure 2 The disassembled section 201 is shown, which includes a carrier section 203 and a cover section 221. Three turbine blades are loaded into the carrier section, as shown by dashed lines. A fourth turbine blade, also shown by dashed lines, is to be loaded into the carrier section 203.

[0045] The carrier segment 203 includes an outer segment 205 and an inner segment 207, which form an outer ring and an inner ring when the segments are assembled into a fixing device ring. The outer segment 205 and the inner segment 207 are fixed together by segment end plates 209 and 211. To improve the stability of the carrier segment 203, two connecting arms 213 and 215 are used to additionally stabilize the outer segment 205 and the inner segment 207. The carrier segment 203 also includes at least two holes 217 (in... Figure 2 In the middle, the second hole 217 is not visible because it is behind the turbine blades already loaded onto the carrier section. These holes are used to allow the shaft of the bottom ring to pass through section 201 so as to properly position the section by piercing it. The carrier section also includes at least two threaded holes 219 (in Figure 2In the middle, the second threaded hole 219 is not visible because it is behind the turbine blades that have already been loaded onto the carrier section. These threaded holes are used to secure the cover section 221 to the carrier section 203 by means of screws 223 and 225.

[0046] The outer ring 205 of the carrier section 203 is formed so that the turbine blade can be placed on the outer ring. The profile may be, for example, a stepped profile so that the turbine blade substrate can be placed thereon. In other words, the profile of the outer ring 205 is adapted to the shape of the turbine blade substrate.

[0047] The inner ring 207 of the carrier section 203 primarily functions to shield the blade tip. This can be an unstructured surface that the blade tip just touches when it is mounted onto the carrier section 203.

[0048] When the cover section 221 is fixed to the carrier section 203, it has the function of securely fixing the turbine blades loaded in the carrier section 203. Therefore, the contour of the cover section 221 is also adapted to the shape of the turbine blade substrate. In order to attach the cover section 221 to the carrier section 203 on which the turbine blades are loaded, the cover section 221 includes holes 227 and 229 corresponding to the threaded holes 219 of the carrier section 203.

[0049] The cover section 221 further includes at least two holes 231 and 233. These holes allow the shaft of the bottom ring to pass through the section 201 so as to properly position the section by piercing it.

[0050] Once the carrier section 203 is fitted with the turbine blades and the cover section 221 is attached to the carrier section, the turbine blade body is sandwiched between the carrier section 203 and the cover section 221, and is thus securely fixed and completely covered. Furthermore, the blade tip is covered by the inner ring 207 of the carrier section 203. However, the turbine blade can be fully accessed from both the top and bottom, and, for example, polishing materials can reach the corresponding surfaces without obstruction.

[0051] Figure 3 and 4 A second embodiment according to the invention is shown. Besides already combined... Figure 2 In addition to the described components and features, segment 201 also includes a carrier segment 203 and a cover segment 221, both of which have several spacer segments 204, 222. At the carrier segment 203, these spacer segments are formed in the lower insertion region 206 at the outer segment 205.

[0052] The cover section 221 includes a spacer section 222 to form an upper insertion region 224. The lower insertion region 206 and the upper insertion region 224 form a two-part insertion to enclose the foot of the turbine blade when the carrier section 203 and the cover section 221 are assembled with the turbine blade mounted between them.

[0053] Furthermore, the inner section or inner ring 207 of the carrier section 203 has a protective extension 208 that extends radially toward the mounted turbine blade and preferably matches the shape and curvature of the blade, like an extension that widens in the inward direction toward the inner ring.

[0054] In the third embodiment of section 201 ( Figure 5 In this configuration, a retaining arrangement structure that provides even greater protection and support for the turbine blades can be achieved. In addition to the spacers 204 and 222 that form the lower insertion region 206 and the upper insertion region 224, a lower notch fit structure 210 and an upper notch fit structure 226 can be formed to press the foot of the blade into the lower insertion gap 206 and the upper insertion gap 224 when the carrier section 203 and the cover section 221 are installed and fixed to each other.

[0055] In addition to these socket areas 206 and 224, an additional thin-walled housing 226 may be provided, which protects the foot of the leaf section like an additional protective sock. Figure 6 These two housings 226 are very thin and match the shape of the blade foot. They are preferably made of a flexible but strong material, such as TPU or similar material, to allow the turbine blade to be elastically but very securely fixed between the carrier section 203 and the cover section 221.

[0056] Figure 7 A fourth embodiment of segment 401 is shown, which allows the blades to be arranged in a double-ring configuration within the carrier 403. The carrier segment 03 includes an outer segment forming a central mounting ring 05 with a lower insertion region 406, an inner segment ring 407 protecting the radially inwardly extending tip of the mounted blade, and an outer segment ring 409 forming an outer segment ring 409 to protect the radially outwardly extending tip of the mounted blade. A cover segment 421 can be secured to segment 403 by screws.

[0057] To allow for a robust yet flexible containment of turbine blades during polishing, these sections are preferably made of a robust yet flexible material, such as thermoplastic polyurethane (TPU) materials and derivatives.

[0058] Figure 8A cross-sectional view is shown through the assembled cylindrical stack 301 according to the invention. The cylindrical stack 301 includes a bottom ring 303, first, second, third, and fourth retaining rings 305, 307, 309, and 311, and a closing ring 313. Except for the cross-sectional view, the bottom ring 303 is fully shown using dashed lines. This allows the showing of shafts, such as shafts 315 and 317, which allow for the loading of the bottom ring 303 with segments and the alignment of said segments with the retaining rings.

[0059] The closing ring 313 is then placed on top of the stack of the bottom ring and the fixing ring and secured with screws. A central shaft is provided at the center of the stack, and the bottom ring and the closing ring are connected to the central shaft via an arm.

[0060] The entire stack can then be secured to a vibrating container, and the structure can be used as a tray system and / or a rotating system.

[0061] List of reference numerals

[0062] 101 Fixing Device Ring

[0063] Sections 103, 105, 107, 109, 111, 113, 115

[0064] Section 201

[0065] 203 Carrier Section

[0066] 205 External Segment (External Ring)

[0067] 207 Internal Segment (Internal Loop)

[0068] Section end plates 209, 211

[0069] 213, 215 Connecting arms

[0070] 217 Hole (for shaft)

[0071] 219 Threaded hole (for screws)

[0072] 221 cover section

[0073] 223, 225 screws

[0074] Holes 227 and 229 (corresponding to threaded hole 219)

[0075] Holes 231 and 233 (corresponding to hole 217)

[0076] 301 Cylindrical stack

[0077] 303 Bottom Ring

[0078] 305, 307, 309, 311 Fixing device rings

[0079] 313 Closed loop

[0080] Shafts 315 and 317

[0081] 204,222 intervals

[0082] 206 Lower insertion area

[0083] 224 Upper socket area

[0084] 208 Extension

[0085] 210, 226 Lower groove fit structure and upper groove fit structure

[0086] 226 Casing

[0087] Section 401

[0088] 403 Carrier (Carrier Section)

[0089] 405 Center Mounting Ring (External Section)

[0090] 406 Lower socket area

[0091] 407 Internal segment ring

[0092] 409 Outer segment ring

[0093] 421 cover section

Claims

1. A section of a fixing device, the fixing device comprising a plurality of such sections arranged to form a fixing device ring, the sections comprising a carrier section and a cover section, wherein, The carrier segment includes an outer segment and an inner segment. When the segment is assembled into a fixing device ring, the outer segment and the inner segment form an outer ring and an inner ring. The outer segment is designed so that the base of the turbine blade can be placed on it, and the inner segment is designed to shield the tip of the turbine blade.

2. The segment according to claim 1, wherein, The outer section includes a lower insertion spacer formed by the spacer section, and / or the cover section includes an upper insertion spacer formed by the spacer section, for retaining and shielding the base of the turbine blades.

3. The segment according to claim 1 or 2, wherein, The inner section has a radial extension that is formed to abut against the tip of the turbine blade for protection.

4. The segment according to claim 3, wherein, The radial extension has a base section connecting the extension to the inner ring and a tip section formed as an extension of the turbine blade that matches the shape and curvature of the tip of the turbine blade mounted in the section.

5. The segment according to claim 1, wherein the segment includes an outer segment disposed radially outside the outer segment, wherein, The outer section is designed such that the base of the turbine blade can be placed thereon, the blade extending radially outward and radially inward, the inner section is configured to shield the tip of the inwardly extending turbine blade, and the outer section is configured to shield the tip of the outwardly extending turbine blade.

6. The segment according to claim 1 or 2, wherein, The segment is made of thermoplastic polyurethane material and its derivatives.

7. A fixing device ring, the fixing device ring being formed from a segment according to any one of claims 1 to 6, characterized in that, It is envisioned that there are components that allow two or more stackable rings to be fixed in a releasable manner.

8. A cylindrical stack of fixing rings, the fixing ring being the fixing ring according to claim 7.

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