Claims:We claim:
1. A fixture device to standardize root and tenon milling operation of steam turbine blades (10), the fixture device comprising:
a base plate (1);
a pair of lateral columns (2) mounted vertically along their length on upper surface of the base plate (1) in such a way that their longitudinal bases lie parallelly opposite to each other with a gap forming therebetween;
a bottom resting pad (5) disposed in the gap formed between the pair of lateral columns (2);
a top clamp (6) disposed in the gap formed between the pair of the lateral columns (2), wherein top face of the bottom resting pad (5) and bottom face of the top clamp (6) are designed with a shape of a blade profile so as to lock vertical movement of a blade (10); and
a root locator (7) fitted at root end of the pair of the lateral columns (2) to define the position of the blade (10) in lateral direction so as to lock the lateral movement of the blade (10).
2. The fixture device as claimed in claim 1, comprises a cylinder piston housing (4) containing cylinder-piston assembly (8), wherein the cylinder piston housing (4) is mounted on top of the pair of lateral columns (2) to provide the required blade holding pressure on the top clamp (6).
3. The fixtured device as claimed in claim 1, wherein the bottom resting pad (5) is selected from various heights and shapes based on the shape and size of the blade (10) to be machined.
4. The fixture device as claimed in claim 1, wherein the pair of lateral columns (2) are mounted vertically along their length on upper surface of the base plate (1) using fastening means.
5. The fixture device as claimed in claim 4, wherein the fastening means includes one of a mounting bolt (3), screw, rivet, and a welding joint.
, Description:TECHNICAL FIELD
[0001] The present disclosure, in general, relates to the milling machines design and development for manufacturing of steam turbine blades. In particular, the present disclosure relates to a fixture device to standardize root and tenon milling operation of steam turbine blades.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present disclosure. 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] New blade shop is generally engaged in manufacturing of steam turbine blades for turbines of various ratings ranging from sub-critical (250/ 270 MW) to super critical sets (660, 700, 800 MW). These steam turbine blades vary in physical aspects such as shape, sizes, etc., depending upon their application. The steam turbine blades are very precise and critical components of a steam turbine system. Therefore, each stage of the steam turbine blades, which are fitted into the turbine rotor, has to be very precise dimensioned.
[0004] These steam turbine blades are manufactured in a setup having highly accurate computer numerical control (CNC) machines. The said setup includes a 5-axis CNC milling machine for complete milling of a blade in one setting and then end milling (root and shroud) of that blade at horizontal milling centers. However, such setup is used for manufacturing of advance designed blades only. The said setup does not include a facility for manufacturing old design blades as the old design blades differ from the advance design blades in their basic shape and size, and thereby fixture to hold such old design blades is not developed while designing present operating system of the setup for advance design blades.
[0005] Therefore, there is a need for a device or setup which can cater the manufacturing of both advance as well as old design turbine blades.
OBJECTS OF THE DISCLOSURE
[0006] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0007] It is a general object of the present disclosure to provide a device for root and tenon milling of old design (T2) steam turbine blades on a computer numerical control (CNC) horizontal machining center which eliminates the disadvantages of the previous existing fixture systems.
[0008] It is another object of the present disclosure to develop the capacity in the advance setup for manufacturing of old design blades.
[0009] It is another object of the present disclosure to shorten the blade manufacturing cycle of old design blades which is presently carried out through conventional setup including machining of various parts of blade on different machines.
[0010] It is yet another object of the present disclosure to improve the productivity of the root and tenon milling of the T2 design steam turbine blades.
[0011] It is yet another object of the present disclosure to improve the quality of T2 design steam turbine blades by manufacturing on the advance machining setup and thereby eliminating rework and rejection through chance manual errors.
[0012] It is yet another object of the present disclosure to carryout root and shroud milling of steam turbine blades by using two adjacent planes in the blade root and shroud as well as the root slot to completely define the position of the blade in the fixture on a horizontal milling machine.
SUMMARY
[0013] This summary is provided to introduce concepts related to milling machines design and development for manufacturing 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.
[0014] In an embodiment, the present disclosure relates to a fixture device for standardizing the root and tenon milling operation of steam turbine blades. The fixture device includes a base plate; a pair of lateral columns mounted vertically along their length on upper surface of the base plate in such a way that their longitudinal bases lie parallelly opposite to each other with a gap forming therebetween; a bottom resting pad disposed in the gap formed between the pair of lateral columns; a top clamp disposed in the gap formed between the pair of the lateral columns, wherein top face of the bottom resting pad and bottom face of the top clamp are designed with a shape of a blade profile so as to lock vertical movement of a blade; and a root locator fitted at root end of the pair of the lateral columns to define the position of the blade in lateral direction so as to lock the lateral movement of the blade.
[0015] In an aspect, the fixture device includes a cylinder piston housing containing cylinder-piston assembly. In said aspect, the cylinder piston housing is mounted on top of the pair of lateral columns to provide the required blade holding pressure on the top clamp.
[0016] In an aspect, the bottom resting pad is selected from various heights and shapes based on the shape and size of the blade to be machined.
[0017] In an aspect, the pair of lateral columns are mounted vertically along their length on upper surface of the base plate using fastening means. The fastening means includes one of a mounting bolt, screw, rivet, and a welding joint.
[0018] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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:
[0020] FIG. 1 illustrates a three-dimensional model of a fixture device in the machine explaining the entire root and tenon milling setup with all parts in assembled condition and a T2 design blade mounted on the fixture, in accordance with an embodiment of the present disclosure;
[0021] FIG. 2 illustrates the implementation of the principle of operation of root and tenon milling of the fixture device, in accordance with an embodiment of the present disclosure;
[0022] FIGS. 3A and 3B illustrate different views of lateral columns designed for side support of a blade, bottom resting pad and top clamp of the fixture device, in accordance with an embodiment of the present disclosure;
[0023] FIG. 4 illustrates a piston-cylinder housing, of the fixture device, for housing a piston-cylinder assembly at its the top, in accordance with an embodiment of the present disclosure;
[0024] FIG. 5 illustrates a base plate to be used at a bottom of the fixture device, in accordance with an embodiment of the present disclosure;
[0025] FIG. 6 illustrates a bottom resting pad for the blade in the fixture device, in accordance with an embodiment of the present disclosure;
[0026] FIG. 7 illustrates an example of a top clamp of the fixture device, in accordance with an embodiment of the present disclosure;
[0027] FIG. 8 illustrates an example of a standard piston-cylinder assembly to be used at the top of the fixture device, in accordance with an embodiment of the present disclosure;
[0028] FIG. 9 illustrates an example of root locator attachment of the fixture device, in accordance with an embodiment of the present disclosure;
[0029] FIG. 10 illustrates an example of a completely finished old design blade, with root and tenon, formed with the fixture device proposed herein, in accordance with an embodiment of the present disclosure; and
[0030] FIG. 11 illustrates an example of a standard hydraulic pipe attached with piston-cylinder assembly of the fixtured device, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] Embodiments explained herein pertain to a protection structure for fuel feed pump of a vehicle. Regardless of their specific construction, a perspective view of a fixture device proposed in accordance with the present disclosure is shown in FIG. 1. The fixture device is used for root and shroud milling works on the principle that the blade axis and the fixture axis remain aligned parallel to each other for carrying out the root and shroud milling. Such principle is illustrated with reference to FIG. 2.
[0037] As shown in FIG. 1, the fixture device includes a base plate (1) acting as the base for the entire setup and gets affixed with a machine palette of a computer numerical control (CNC) machine (FIG. 5). On top of the base plate (1), a pair of U-shaped lateral columns (2), as shown in FIG. 3, are mounted with the help of mounting bolt (3). The U-shaped lateral columns (2) are mounted in such a way that the bases of both the U-shaped lateral columns (2) are facing each other to form an I-shape from the mounting of both the U-shaped lateral columns (2) on the base plate (1).
[0038] In an aspect, on top of the lateral columns (2), a cylinder piston housing (4) is fitted which in turn houses a cylinder-piston assembly (8).
[0039] In an aspect, the lateral columns (2) are mounted on the base plate (1) with a gap in therebetween, with said gap being used for rigidly holding a turbine blade (10) between a resting pad (5) (FIG. 6) and a top clamp (6) (FIG. 7) to arrest vertical movement of the turbine blade (10).
[0040] The top face of the bottom resting pad (5) and the bottom face to the top clamp (6) is designed in exact shape of a blade profile. Such shaping allows complete locking of the turbine blade (10) in vertical direction while keeping its axis horizontal.
[0041] The top clamp (6) is attached to the piston-cylinder assembly (8) and is used to clamp the blade from the top. The lower surface of top clamp (6) is also designed in the shape of suction face of the blade so as to completely arrest the vertical degree of freedom of the blade while keeping its axis horizontal.
[0042] By locking the position of turbine blade (10) in vertical direction through bottom resting pad (5) and the top clamp (6) and defining the position of the turbine blade (10) in lateral direction through a root locator (7), root and tenon milling of these turbine blade (10) is carried out with required precision.
[0043] Accordingly, to lock the lateral movement of the turbine blade (10), a root locator (7) is provided. The root locator (7) is fitted at root end of the lateral columns (2) to define the position of turbine blade (10) in lateral direction and to lock the lateral movement of the turbine blade (10). In other words, the root locator (7) is mounted on the lateral columns (2) and is used to define the position of the turbine blade (10) in horizontal direction along its axis, as shown in FIG. 9.
[0044] FIG. 10 shows an example of a completely finished old (T2) design blade (10), with root and tenon, formed with the fixture device proposed herein. This blade (10) shown in FIG. 10 is the final product of the process where proposed fixtured device is to be used. FIG. 11 illustrates an example of a standard hydraulic pipe (9) attached with piston-cylinder assembly (8) of the fixtured device, in accordance with an embodiment of the present disclosure.
[0045] Thus, with the implementation of the present disclosure, the fixture device proposed herein uses resting pads (5) of various heights and shapes in accordance with shape and size of the blade (10) to be machined. On these resting pads (5), flat surfaces of the blade root and shroud are rested and height and angle of the resting pads (5) are designed in such a way that central axis of the blade (10) becomes horizontal. The main challenge in root and shroud milling of old (T2) design blade lies in the fact that these blades do not have a shroud block that can be used as a reference. Thus, the fixture device proposed herein cannot be used to carry out root and shroud milling of these old design blades.
[0046] However, in the proposed fixture device, profile of the blade (10) is taken as the reference to define the position of the blade (10) horizontally.
[0047] It can be appreciated by those skilled in the art that all the components or elements of the fixture device proposed herein have been hardened before utilizing of the same.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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.