Claims:We claim:
1. A device for root and shroud milling of small size steam turbine blades with length less than 100 mm on a computer numerical control (CNC) horizontal machining center, the device comprising:
a root base pad (1) for positioning of root of a blade (4) on its top;
a shroud base pad (2) for positioning of shroud of the blade (4) on its top; and
a root locator (3) for fixing the position of the blade (4) in the longitudinal direction along its length.
2. The device as claimed in claim 1, with the position and orientation of the blade (4) resting on the device where axes of the blade (4) is kept horizontal and aligned to the axes of a machine.
, Description:DEVICE FOR FACILITATING ROOT AND SHROUD MILLING OF STEAM TURBINE BLADES WITH LESS THAN 100 MM LENGTH
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to rigid and uniform clamping device for steam turbine blades (TX, 3DS & F) of all small size with length less than 100 mm while root and shroud machining on computer numerical control (CNC) horizontal machining center.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed subject matter, or that any publication specifically or implicitly referenced is prior art.
[0003] Steam turbine blade is a very precise and critical component of a steam turbine system. Root and shroud milling of said blade are typically carried out on Heller machines. However, the length of the blade received for root and shroud milling is generally higher than 125-130 mm. Having such length, different fixed pads are required in the Heller machines to clamp said blade in horizontal position so that said blade and machine axes are aligned parallel to each other during milling.
[0004] In view of the above, it will be apparent to the skilled artisan that there exists a need in the art for an improved fixture pads for facilitating root and shroud milling of steam turbine blades.
OBJECTS OF THE DISCLOSURE
[0005] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0006] It is a general object of the present disclosure to provide a device for root and shroud milling of small size steam turbine blades on Heller machine which eliminates the disadvantages of the previous existing fixed pad systems.
[0007] It is another objective of the present disclosure to enhance the capacity of Heller machine for root and shroud milling of a larger variety of steam turbine blades.
[0008] It is yet another object of the present disclosure to shorten the total product cycle time required for manufacturing of small size blades.
[0009] It is yet another object of the present disclosure to improve the productivity of root and shroud milling of steam turbine blades.
[0010] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.
SUMMARY
[0011] This summary is provided to introduce concepts related to fixture pads for facilitating root and shroud milling of steam turbine blades. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0012] In an embodiment, the present disclosure relates to a device root and shroud milling of small size steam turbine blades with length less than 100 mm on a computer numerical control (CNC) horizontal machining center. The device includes a root base pad for positioning of root of a blade on its top; a shroud base pad for positioning of shroud of the blade on its top; and a root locator for fixing the position of the blade in the longitudinal direction along its length.
[0013] In an aspect. With the position and orientation of the blade resting on the device, axes of the blade are kept horizontal and aligned to the axes of a machine. After fixing the position of the blade in vertical and horizontal directions, the blade is rigidly fixed by top clamps and machining of root and shroud is carried out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0015] FIG. 1 illustrates an example of an entire setup in which fixture with all pads proposed herein is mounted and a blade us clamped on the pads, in accordance with an embodiment of the present disclosure;
[0016] FIG. 2 illustrates a principal of operation of root and shroud milling on the blade, in accordance with an embodiment of the present disclosure;
[0017] FIGS. 3A-3D illustrate basic steps for placement and clamping of steam turbine blade on proposed pads and fixture, accordance with an embodiment of the present disclosure;
[0018] FIGS. 4A-4C illustrates different views of proposed pads, in accordance with an embodiment of the present disclosure;
[0019] FIGS. 5A-5C illustrate three-dimensional views of root locator attachment, in accordance with an embodiment of the present disclosure; and
[0020] FIG. 6 illustrates a three-dimensional view of shroud base pad assembly on which the shroud of the steam turbine blade rests.
DETAILED DESCRIPTION
[0021] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0022] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0024] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0026] Embodiments explained herein pertain to a protection structure for fuel feed pump of a vehicle. Regardless of their specific construction, FIGS. 1-6 show specially designed fixture pads and locators used for root and shroud milling of small size steam turbine blades.
[0027] FIG. 1 illustrates an example of an entire setup in which fixture with all pads proposed herein is mounted and a blade us clamped on the pads, in accordance with an embodiment of the present disclosure.
[0028] FIG. 2 illustrates a principal of operation of root and shroud milling on the blade on Heller machine. As shown in FIG. 2, the operation of root and shroud milling involves mainly two steps: first, alignment of blade axes along the machine axes and second, fixing the position of blade for machine’s reference.
[0029] The device proposed herein takes care of the mentioned principle of operation through a root base pad (1), a shroud base pad (2), and a root locator attachment (3).
[0030] FIGS. 3A-3D illustrate basic steps for placement and clamping of steam turbine blade on proposed pads and fixture, accordance with an embodiment of the present disclosure. FIG. 3A shows the placement of a blade (4), on its rhomboid shape, root and shroud base pads (1, 2). In an aspect, the contact surfaces of root and shroud base pads (1, 2) are designed so that it matches the contact surfaces of the blade (4) rhomboid and its height is designed just enough to keep the axis of the blade horizontal same as the axis of the device.
[0031] FIG. 3B shows clamping of the blade (4) at the root base pad (1) by a top clamp (5). FIG. 3C further shows clamping of the blade (4) at the shroud base pad (2) by another top clamp (5). Finally, FIG. 3D shows that the end support (6) is retracted to free the root end blade (4) for milling.
[0032] Now, once the lade (4) is fixed, root and shroud milling operation takes place at the two ends of the blade (4). The dimensions generated during root and shroud milling are total (final) blade height and tang height (position of root slot from the bottom of the blade (4)). To generate these two dimensions, position of the blade (4) on the device or machine fixture along its length is important. This position is fixed by the root locator attachment (3) which locks the longitudinal position of the blade (4). FIGS. 5A-5C illustrate three-dimensional views of root locator (3), in accordance with an embodiment of the present disclosure. The function of the root locator (3) is to fix the position of blade (4) in longitudinal direction along its length.
[0033] After precise placement of the blade (4) on the device or the machine fixture with help of these two attachments, the blade (4) is rigidly clamped in the device/machine and root and shroud milling operation is carried out.
[0034] Further, in an aspect, the contact surfaces of the resting root and shroud base pads (1, 2) are designed to match the angle and size of the blade (4) so as to keep the axis of the blade (4) horizontal, thereby fixing the position of the blade (4) in vertically.
[0035] It can be appreciated by those skilled in the art that all the components or elements of the device/machine proposed herein have been hardened before utilizing of the same.
[0036] Further, it will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope.
[0037] Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.
[0038] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0040] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0041] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.