Description:DESCRIPTION
“A CLAMPING MECHANISM TO SAFELY HANDLE LARGE DIAMETER HEMISPHERICAL DISHED END OF NUCLEAR HEAT EXCHANGER”

FIELD OF INVENTION
[001] The invention is generally a design of a clamping device to hold and handle a large diameter hemispherical dished end (weight around 10 metric tons) of a nuclear heat exchanger fabrication process. The device is a temporary mechanical joints arrangement, which will eliminate the need of permanent buttering on job and number of welded type lug supports to handle the job during its various fabrication stages.
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] The dome shaped hemispherical large diameter dished end is an integral part of nuclear steam generator. This dished end consists of multiple numbers of nozzles and has projection outside.

[004] The job dished end needs to be held using lug supports those are welded in the surface. Using this lug supports (4 numbers perpendicularly opposite) on the job periphery plane, the job is handled for different orientation by using crane facility.

[005] The drawback using this method is, these lug supports are not part of original dished end and are removed after the dished end is in ready condition for next assembly. After removal of the lugs, the variation in surface hardness property on the lug welded zone from the rest of the dished end is observed as these area are carried with buttering activity. Since the dished end is a pressure part component of nuclear steam generator, hence the variation of property, specially the surface hardness, may lead to propagation of crack and thus may lead to catastrophic failure while in operation.
[006] To eliminate this, a clamping device is needed that does not require buttering on job, is removal type and at the same time can act equivalent to the permanent lugs supports. The arrangement comprises of one solid ring (that match seats on top taper edge surface plane of the hemispherical job) and another two removal type half clamps that makes the bottom flange. The top ring seats on the top of the job whereas the bottom one seats slightly below plane on the side surface of the job. The inner diameter surface of the bottom ring matches the side geometry of the job.

[007] Both the top and bottom rings having slight gap, are clamped together using fasteners. Thus both the rings become integrated due to the shear load on bottom ring and compressive load on top ring consequently.

[008] Moreover, to avoid rotation chance of this integrated ring assembly during operation, two hub assembly is designed that connects and locks the clamping device separately with the job nozzle projection in such way that rotational constraints are also achieved.
PRIOR ART
[009] Now, reference may be made to the following prior art.
CN212526942U
[0010] It is directed to Machining with hemisphere casing vacuum adsorption frock clamp.
[0011] The utility model provides a hemisphere casing vacuum adsorption frock clamp for machining related to the machine-building processing field. The tool clamp is connected with the vacuum pump through the gas receiving end, so that clamping is realized in a vacuum adsorption mode when a work piece is clamped. The utility model discloses a design for the clamping of solving thin wall ball class casing part, use the utility model discloses the difficult problem of the not good clamping of solution hemisphere casing that can be fine, the deformation of effectual control clamping, and the clamp force is reliable, and the clamping process is steady, and the centre of sphere is to paste automatic completion location, and vacuum adsorption press from both sides tightly.

[0012] The invention is a vacuum absorption technique of holding a hemispherical job and is not related to mechanical clamping using fasteners. More over the job here is a thin wall shell whereas the present invention can handle job of both thin wall and thick wall profile job. The prior art is not related to nuclear heat exchanger.
OBJECTS OF THE INVENTION
[0013] An object of the invention is to provide a clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger.

[0014] Another object of the invention is to provide a clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger, which obviates short comings of the prior art(s).

[0015] Yet another object of the invention is to avoid requirement of permanently welded lug supports that creates surface hardness variation in dished end after its removal.

[0016] Still another object of the invention is to safeguard the job safety during manufacturing stages.

[0017] 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:
[0018] 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.

[0019] The invention is related to a device to facilitate safe and steady holding and titling of a hemispherical large diameter curved shaped plate (which comprises of 5 asymmetric nozzle through holes on its surface) to any of the axis mechanically.

[0020] The arrangement comprises of one solid top ring (that seats on top surface plane of the hemispherical job with a taper surface) and a bottom ring comprises of two removal type half clamps placed slightly below the top ring plane. The top ring seats on the top of the job whereas the bottom one seats on the sides of the curved surface of job. The inner diameter surface of the bottom flange rings exactly matches the side geometry of the job.

[0021] Both the top and bottom rings are clamped together using fasteners which are distributed equally in the flange rings. Due to the shear load on bottom ring id seating surface and compressive load on top ring, the top and bottom flanges when come closer get locked naturally, thus working equivalent to a permanent member with the job.

[0022] Moreover, to avoid chance of rotational slippage between the temporary flange and the hemispherical job, two separate hub assembly is designed that connects the temporary flange with the job nozzle projections area and acts as lock for any relative rotational movement between the job and clamping device during the operation.

[0023] 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.

[0024] 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.

[0025] 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 DESCRIPTIONS OF THE ACCOMPANYING DRAWINGS
[0026] 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:-

[0027] Figure-1 illustrates the hemispherical job with 5 nozzles holes on its surface.

[0028] Figure 2 illustrates the above invention assembly with the large diameter hemispherical job.

[0029] Figure 3 illustrates the device Assembly with Job in 3d model.

[0030] Figure 4 illustrates the device assembly without job in 3d model view i.e. a clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger according to the present invention.

[0031] Figure 5 illustrates the top ring flange.

[0032] Figure 6 illustrates the Bottom ring flange with plates.

[0033] Figure 7 illustrates the rotation arresting clamp assembly with Connecting flange assembly and plates.

[0034] Figure 8 illustrates the clamp with plates.

[0035] Figure 9A illustrates the Anti-rotational flange assembly.

[0036] Figure 9B illustrates the special fasteners.

[0037] Figure 10 illustrates the Spacer pipe to avoid buckling in case of over tightening of fasteners.

[0038] Figure 11 illustrates the assembly of below features:
Taper surface bottom flange: (3, 8)
Anti-rotation assembly: (12)
Nozzle projection as support: (N)
Dome shape job: (J)
Top Flange: (1)
Taper surface for top ring: (T)
[0039] 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 THE INVENTIION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

[0040] 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.

[0041] The present invention makes a disclosure regarding a technology pertaining to a clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger.

[0042] The mechanism and the parts of the inventions are explained with the above mentioned figures and drawings.
[0043] Reference may be made to figure 1, wherein the job of a large diameter hemispherical dome shaped object is shown. The job has circular through holes of multiple variants as nozzle hole meant for flow of medium.

[0044] Initially the job is kept in the ground in rigid and safe position. Thereafter, top flange (1) is placed on the top surface of the dome. The surface slope of the flange (1) exactly matches with the slope of the dome top surface. This is shown in Section A-A of fig. 5.

[0045] Then, Bottom flange-1 (2) and Bottom flange-2 (7) which are half clamp time plates are assembled from side of the dome slightly below the top flange. The plate Internal Diameter is slightly tapper to match with the Outer diameter of the hemispherical dished end as shown in section CC. This assembly is carried out by fastening the rectilinear flange (4 and 9) using fasteners (22, 23).

[0046] During the assembly of said Bottom flange -1 (2) with Bottom flange-2 (7) a crane/mechanical support is required to place them in position from horizontal sideways.

[0047] Both top and bottom flange ring have plurality of through holes as shown in figure 5.
[0048] Once the top and bottom flange rings are assembled individually, spacer (27), which is spacer pipe, is placed between them.

[0049] Due to the clearance, compressive tightening is possible and at the same time once the gap is closed, buckling due to chance over tightening of flanges is naturally avoided.

[0050] After that, using fasteners (19, 20, 21), top flange and bottom flanges are tightened. This enables the flange to come closer and due to dome profile of the job both the flanges naturally get locked with the job.

[0051] To avoid over tightening, said spacer pipe (27) comes into action and stops the flanges from over buckling.

[0052] Once the flanges are tightened, a rotational movement is still possible between the flange and the job. To avoid this, anti-rotation flange assembly (12) is introduced.

[0053] The anti-rotation flange assembly (12) comprises of Connecting flange assembly (13) with multiple plates (14, 15, 16, 17 and 18).
[0054] The anti-rotation flange assembly (12) is placed upon one of the nozzle projections on the dome and clamped with the help of at least two Connecting flange assembly (13) using fasteners (24, 25, 26).

[0055] The invention takes care of avoiding of any vertical projection of fasteners (bolts, nuts) from the top flange (1). This technique helps the job to be smoothly kept upside down on the top flange in any surface table or machine bed without any interference.

[0056] In parallel, using a plate (18) with through hole, anti-rotation flange assembly (12) is clamped with bottom flange ring. This mechanism connects the flange assembly and the nozzle supports resulting in locking of rotation.
[0057] There are two connecting flange assembly used for taking support from two oppositely positioned nozzles on job.

[0058] Multiple plates (10) are welded with the bottom flange. The fixture with the job can be lifted, tilted, positioned for various fabrication such as cladding, welding, machining and inspection process.

[0059] The top flange ring and bottom flange ring are locked using bolted joints. Due to the hemispherical geometry of the job and its taper top surface, the two flanges get auto locked using fasteners and can become an integral part of the job acting equivalent to permanent lug supports. Using the through holes in the clamping device, the job can be tiled, rotated and positioned at different angles which are required for various manufacturing and inspection stages of the dished end.
[0060] The invention can be used in similar kind of job handling in other industries as well.
[0061] Thus, according to the invention there is provided a clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger comprising of:

[0062] Top flange ring (1) with multiple holes, Bottom flange ring (2), which is assembly of at least two half ring having multiple through holes, Plate (4) orthogonally connected with Bottom flange-I (3), that facilitates the clamping of the bottom flange ring (2) and Bottom flange assembly-II (7), Plates (5 and 11) welded with the Bottom flange-I (3) and Bottom flange-II (8) to handle the overall assembly with job, Spacer pipe (27) placed between the top flange (1) and bottom flange (2) Anti-rotational flange assembly (12) mounted on the bottom flange ring (2) for rotational contracts of the clamping device as in figure 4.

[0063] The Anti-rotational flange assembly (12) comprising of Connecting flange assembly (13) with multiple plates (16,17,18) The Anti-rotational flange assembly (12) connects the nozzle projection with assembly of the bottom flange (2) using fasteners (24,25,26), in which the anti-rotation mechanism locks the relative motion between the flange assembly and hemispherical job.
[0064] The Spacer pipe (27) is lower in height than the natural gap between the top and bottom flange (1 and 2).

[0065] The clamping of the bottom flange ring (2) and Bottom flange assembly-II (7) is carried out by bolts and nuts.

USEFULNESS/ADVANTAGES OF PRESENT INVENTION
• With the help of present invention, the clamping device can become integral with the job and the structure can be safely handled in shop floor in totality. This eliminates the need of a permanent structure just to lift and handle the job.
• The device can be disassembled once the job fabrication is over and is ready for the next assembly.
• The invention can be used in nuclear application as well as in similar kind of job geometry in other industrial application.
• The invention eases the manufacturing process by replacing the lug which would have needed special care for metallurgical treatment during its removal at final stage of fabrication.
• The alternate clamping methods is of temporary type and can be easily assembled and disassembled.
• Since clamping plate is a ring type design, hence multiple location holes are possible on the ring plate to hold and handle the job as per manufacturing needs.
• The clamp plate is as much strong as the permanently welded lug support.
• Using the clamp, the job can be tilted at any angle with the datum plane such as 45 degree, 90 degree, 135 degree.
• Since the dished end is of bigger diameter and of nuclear power application, hence the present invention safeguards the job safety during manufacturing stages.
WORKING OF INVENTION
• Before this invention, the handling of hemispherical dished end are handled by temporary lugs and this temporary lugs are attached to dished end by buttering and welding.
• After removal of temporary lugs from dished end, the surface of removed regions on dished end are subjected to surface examination by liquid penetrant method / magnetic particle method and hardness values are examined. The hardness values on the examined regions are generally higher than the non-attachment region and it is subjected to the non-conformance reports.
• This invention has eliminated the buttering and welding of temporary handling lugs, which improves the quality of heat exchanger and decreases the cycle time in manufacturing.
• This invention will also rigidly hold the dished end during cladding, post weld heat treatment and various machining process and quality inspection stages with put distortion.
TEST RESULT
• In prior art, dished end is clamped by vacuum pumps for machining related to machine-building processing field. The dished end is not subjected to cladding and hence the prior art invention is not subjected to higher heat input and post weld heat treatments.
• Present invention is exposed to higher heat input and post weld heat treatments.
• The local surface hardness on dished end has not changed due to elimination of buttering and welding for temporary lifting lug.

REFERENCE NUMERALS
Item no. Description
1 Top flange
2 Bottom flange assembly.-I
3 Bottom flange-I
4 Plate
5 Plate
6 Plate
7 Bottom flange assembly.-II
08 Bottom flange-II
09 Plate
10 Plate
11 Plate
12 Anti-rotational flange assembly.
13 Connecting flange assembly
14 Plate
15 Plate
16 Plate
17 Plate
18 Plate
19 FD Stud
20 Nut Hex.
21 Washer Punched A39
22 HSFG Hex. Bolt & Nut
23 Washer
24 Stud
25 Nut
26 Washer
27 Spacer pipe

[0066] 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.

[0067] 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.

[0068] 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 analogues 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”.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.
, Claims:We Claim
1.A clamping device to safely handle large diameter hemispherical dished end of nuclear heat exchanger comprising of:

Top flange ring (1) with multiple holes,
Bottom flange ring (2), which is assembly of at least two half ring having multiple through holes,
Plate (4) orthogonally connected with Bottom flange-I (3), that facilitates the clamping of the bottom flange ring (2) and Bottom flange assembly-II (7),
Plates (5 and 11) welded with the Bottom flange-I (3) and Bottom flange-II (8) to handle the overall assembly with job,
Spacer pipe (27) placed between the top flange (1) and bottom flange (2)

Anti-rotational flange assembly (12) mounted on the bottom flange ring (2) for rotational contracts of the clamping device as in figure 4.

2. The clamping device as claimed in claim 1, wherein the Anti-rotational flange assembly (12) comprising of Connecting flange assembly (13) with multiple plates (16,17,18)

3. The clamping device as claimed in claim 1 or 2, wherein the Anti-rotational flange assembly (12) connects the nozzle projection with assembly of the bottom flange (2) using fasteners (24,25,26), in which the anti-rotation mechanism locks the relative motion between the flange assembly and hemispherical job.

4. The clamping device as claimed in claims 1-3, wherein the Spacer pipe (27) is lower in height than the natural gap between the top and bottom flange (1 and 2).

5. The clamping device as claimed in claims 1-4, wherein the clamping of the bottom flange ring (2) and Bottom flange assembly-II (7) is carried out by bolts and nuts.