Claims:WE CLAIM:

1. A method for placing and self-centering of intermediate pressure inner casing on turn table comprising steps of:
- placement of an irregular job on a reference/base plate [B];
- marking of reference line as per profile of the irregular job on the base plate [B];
- fixing of a plurality of blocks [A] onto the Plate [B] at the marked profile maintaining a gap between the blocks [A];
- displacing the irregular job;
- shifting the base/reference plate [B] to turn table followed by centering;
- placing the irregular job on the reference plate [B] for centering on the turn table.

2. The method as claimed in claim 1, wherein the irregular job includes casing [E].

3. The method as claimed in claim 1 or 2, wherein the blocks [A] are welded onto the plate [B].

4. The method as claimed in claims 1-3, wherein the plate is rectilinear in shape and having thickness of 5-15 mm, which is made of material including mild steel.

5. The method as claimed in claims 1-4, wherein the block [A] forms a plate, which is chamfered on one side so as to facilitate placement of the casing by crane on the reference plate [B] while centering.

6. The method as claimed in claims 1-5, wherein the chamfered angle is 20-40 degrees and the block [A] is made of material including mild steel.

7. The method as claimed in claims 1-6, wherein this reference plate [B] is put on turn table and Centred accordingly by adjusting it with hammering, in which the reference plate [B] is clamped on the turn table with the help of T-slots, which is followed by placing said casing [E] on the reference plate [B] by a crane.
, Description:METHOD FOR PLACING AND SELF-CENTERING OF I.P. INNER CASING ON TURN TABLE

FIELD OF INVENTION:
[001] The invention relates to a design and fabrication of a fixture to place intermediate pressure (IP) casing on the turn table at Advanced Ultra Super Critical (AUSC) work station. More particularly, the invention relates to a method by which IP inner casing of irregular shape could be placed and self-centered on the turn table without any chuck / jack for centering purpose at Hot Wire Narrow Gap TIG welding station under AUSC project. Thus, the invention is directed to method for placing and self-centering of intermediate pressure inner casing on turn table.

BACKGROUND OF THE INVENTION:
[002] 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 invention, or that any publication specifically or implicitly referenced is prior art.

[003] Advanced Ultra Super Critical (AUSC) technology refers to an advanced coal-based power generation system that works on higher temperatures (above 700°C) and pressures for improved efficiency, reducing coal consumption and CO2 generation. BHEL Haridwar is designing and developing the technology for AUSC turbine under which Rotor and Casing to be designed and developed. For this, various technological methodology is adopted like many fixtures development, welding process parameters and cleaning of weld bead at various stage and so on.

[004] IP Inner Casing was in three parts of irregular shape and of 12 to 15 TON weight of each part. These parts have to be welded in vertical position by Tungsten inert gas (TIG) process. Welding Torch has to be fixed in horizontal (2G) position.

[005] In order to meet the above requirements, it was a big challenge to centre the IP Inner Casing without any chuck/ jack type arrangement with turn table of welding machine. To place the casing on the machine’s turn table as in desired position, the present invention was adopted relating to method for placing and self-centering of intermediate pressure inner casing on turn table.

[006] The present invention involves design and fabrication of a fixture to place IP casing on the turn table at AUSC work station for narrow gap hot wire TIG welding under AUSC mission project.

OBJECTS OF THE INVENTION:
[007] An object of the invention is to provide a method for placing and self-centering of intermediate pressure inner casing on turn table, which is simple and obviates short comings of the prior art(s).

[008] Another object of the present invention to propose, a unique methodology by developing an innovative fixture to place any irregular job irrespective of their shape, size and weight on turn table without any Chuck/ jack system for centering purpose.

[009] Yet another object of the invention is to self-center the job with turn table without any extra effort with the help of EOT crane in one go.

[0010] One another object of the present invention is to propose, a unique fixture to place IP inner casing with reduced or minimal cycle time.

[0011] Still another object of the present invention is to propose, a systematic approach to place heavy casings on the turn table for narrow gap TIG welding.

[0012] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:
[0013] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

[0014] Under a developmental project, one part of IP Inner casing of irregular shape has to be placed on the other upper part on the turn table of Hot Wire Narrow Gap TIG welding Station. Both the parts have to be centered with turn table. But there was no chuck / jack type arrangement with the turn table. Due to its heavy weight, it was not possible to adjust the position of job on the turn table for its centering. Therefore, our challenge was to place the IP Inner Casing on the turn table with proper centering in first go with the help of overhead crane only.

[0015] In order to meet the requirement, there is a need to place the irregular shaped heavy casting of about 30 TON on turn table of Hot Wire Narrow Gap TIG Welding Station without any chuck/ jack type arrangement for centering purpose.
[0016] An innovative method was adapted to place this heavy casing at turn table with proper centering for smooth operation of welding.

[0017] It was difficult to place the casing on turn table directly at desired position with accuracy. So plan was to place casing at reference plate having optimum thickness. First the reference plate was placed on any other bed. Then IP Casing was placed on the reference plate. After putting Casing on reference plate, it’s outer profile was marked on reference plate with the help of any pointed tool so that this casing profile can be transferred to the reference plate. Thereafter, multitude of guiding blocks (A) were tack welded at various locations (8 to 12 numbers) depending upon the sizes of casing. Then casing was removed from the reference plate. Soon after this reference plate was put on turn table and Centred accordingly by adjusting it with small hammering. Once this reference plate gets centered with turn table, it is properly clamped on the turn table with the help of available T-slots. Now, said casing is placed on the reference plate by means of crane. Here, with the help of guiding blocks (Part-A) casing rests on the earlier position. Thus automatically casing comes in desired location. No forces or effort will be required to relocate or re-centre it. Casing will rest in proper position in one go.

[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.

[0019] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

[0020] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
[0021] 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 processes that are consistent with the subject matter as claimed herein, wherein:-

Figure 1 illustrates: typical schematic view of fixture plate of the present invention.
Figure 2 illustrates: typical schematic view of developed fixture plate according to the invention.

[0022] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
[0023] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0024] Although embodiments for the present subject matter have been described in language specific to package features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

[0025] As per prior art, or in the current power plant technology also known as the Supercritical technology, single piece casting is being used for inner casing upper and lower half of the Intermediate Pressure (IP) Turbine. While in the current AUSC technology, this inner casing upper and lower half of the Intermediate Pressure (IP) Turbine is in three parts including dissimilar combination. Hence, there was a need to weld these heavy casings at AUSC work station by using Narrow Gap TIG welding process with proper welding accuracy and centering.

[0026] Since it was difficult to place casing at turn table directly with desired accuracy. The following method was developed and implemented, for which protection is sought.

[0027] A typical view of casing [E] used in AUSC project is shown in figure-2. This casing has to be placed on the turn table with another dissimilar one on the top of this with same center and desired location to be welded together.

[0028] Here, casing [E] has been given as an example. However, any irregular job irrespective of their shape, size and weight can be used in place of casing on turn table without any jack system for centering purpose.

[0029] As per invention a reference fixture plate constituting base plate [B] as shown in figure-2 is fabricated with optimum thickness. The plate is rectilinear in shape and having thickness of 5-15 mm. It can be made of material including mild steel.

[0030] Further reference block [A] as shown in figure 2 is designed and fabricated. This block [A] is a plate of suitable size, which is chamfered on one side. The chamfered angle is 20-40 degrees so as to facilitate placement of the casing by crane on the reference plate [B] while centering. The block [A] can be made of material such as mild steel.

[0031] The materials given above are as example without restricting scope of the invention to the same. Thus, other materials readily apparent to a person skilled in the arts are understood to be within purview of the invention.
[0032] Now reference may be made to Figure-2, wherein the casing [E] is placed on the base plate [B] then a reference line is marked as per profile of the casing (E) on the base plate [B] and later casing is removed from reference plate (B).

[0033] A plurality of blocks [A] are welded onto the Plate [B] at profile marked earlier. Thus, suitable number of blocks [A] are placed along the marked profile i.e. along the circumference of the casing maintaining gap between the blocks. After placing said blocks [A] by tack weld on the Reference plate [B], the casing is shifted to another location. Here, the casing is free and the blocks [A] are mounted on the base/reference plate [B]. Thereafter, the base/reference plate [B] is shifted to turn table.

[0034] Thus, this reference plate [B] is put on turn table and Centred accordingly by adjusting it with small hammering. Once this reference plate gets centered with turn table, it is properly clamped on the turn table with the help of available T-slots. Now, said casing [E] is placed on the reference plate by means of crane. Here, the casing is guided to sit-back again at marked profile by means of Guide cum reference blocks (A).

[0035] Thus with the help of guiding blocks (A) casing rests on the earlier position. Thus automatically casing comes in desired location. No forces or effort is required to relocate or re-centre it. Casing will rest in proper position in one go.

[0036] As base/reference plate [B] is very less in weight, hence it can be placed on turn table easily as per profiled marked on it.

[0037] Once this reference plate (B) is set as per profiled marked, it is fixed with the turn table. Now heavy casing is lifted by crane and placed on profile marked earlier with the guide of blocks [A] as shown in figure-2.
[0038] Thus automatically casing is at desired position and centred on the turn table and further no movement is required.

WORKING OF THE INVENTION
[0039] The method for placing and self-centering of intermediate pressure inner casing on turn table comprises the following steps:
- placement of an irregular job on a reference/base plate [B];
- marking of reference line as per profile of the irregular job on the base plate [B];
- fixing of a plurality of blocks [A] onto the Plate [B] at the marked profile maintaining a gap between the blocks [A];
- displacing the irregular job;
- shifting the base/reference plate [B] to turn table followed by centering;
- placing the irregular job on the reference plate [B] for centering on the turn table.

ADVANTAGES OF THE INVENTION
[0040] Centering can be carried out on turn table without any jack system;
[0041] A unique fixture plate to place IP inner casing with reduced or minimal cycle time;
[0042] A systematic approach to place heavy casings on the turn table with self-centering by EOT crane;
[0043] Method can be used for any irregular job irrespective of their shape, size and weight;
[0044] Present invention is used to weld bi-metallic casings or any other product having similar type of placing issues.

TEST RESULT
[0045] IP casing was welded successfully with help of this innovation. Total three parts have been kept on turn table on each other at proper centre. Weld quality was acceptable and remarkable cycle time was reduced.

[0046] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other cast structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter 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.

[0047] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0048] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0049] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogue to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0050] The above description does not provide specific details of 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 various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.