Claims:WE CLAIM
1. A method (400) for bending tubes in a furnace vertical wall side panel, the method comprising of steps:
setting (401) a first set of tubes (201) and a second set of tubes (202) to form the vertical wall side panel, wherein the first set of tubes (201) are longer than the second set of tubes (202);
inserting (402) a bracing plate (203) over the first set of tubes (201);
transferring (403) the furnace vertical wall side panel to a furnace followed by a heat treatment; and
bending (404) the first set of tubes (201) by a bending machine.
2. The method (400) as claimed in claim 1 wherein, the first set of tubes (201) and the second set of tubes (202) are arranged alternatively to each other.
3. The method (400) as claimed in claim 1-2 wherein, the first set of tubes (201) accommodate 90° bends (103).
4. The method (400) as claimed in claim 1 wherein, the bracing plate (203) has plurality of holes (204).
5. The method (400) as claimed in claim 4 wherein, the bracing plate (203) has a definite pitch dimension.
6. The method (400) as claimed in claim 1 wherein, the first set of tubes (201) as a single entity is transferred for bending in a gang bending machine.
, Description:A METHOD FOR BENDING TUBES OF A FURNACE VERTICAL WALL SIDE PANEL

FIELD OF THE INVENTION
[0001] The present subject matter described herein relates to a method of bending tubes of a vertical wall side panel. More specifically, the present invention relates to the method of bending terminal tubes of vertical wall side panel present in a high pressure steam generator to eliminate individual bending of the tubes and also to eliminate Tungsten Inert Gas (TIG) joints associated to it that correspondingly caters to the unsafe working conditions.

BACKGROUND OF THE INVENTION
[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 invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In high pressure steam generators, which operates above supercritical temperature and pressure. The Furnace vertical wall side Panels are manufactured with tubes and fin flat in panel forming machine. This Panel is consisting of straight portion and terminal portion.
[0004] Generally, a high pressure steam generator consists of 20 to 24 furnace vertical wall side panels that are arranged in such a way that half the quantity of the vertical wall side panels constitutes the left hand side wall and remaining half constitutes the right hand side wall. Each vertical wall side panel consists of 30 to 36 tubes and equal number of fin flats.
[0005] Referring to Fig. 1, the conventional method of furnace vertical wall side panels manufacturing is disclosed. The straight portion of the panel is formed firstly with tubes (101) and fins (102) in the panel processing machine. After formation of the panel, stress relieving is done in furnace. The tubes (101) and the fins (102) are welded on the panel. After the attachment welding, stress relieving is done.
[0006] The terminal portion (108) consists of bend tubes and there are mainly two types of bends, i.e. 90° bends (103) & off-set bends (104). The bents in the tubes are made in the rotary bending machine.
[0007] Further, a lug (105) is welded to terminal bends. The bend tubes (103, 104) and the lug (105) then further goes for stress relieving. The bend tubes (103, 104) and the lug (105) are fed manually to one end of panel and are tack welded. The alignments of bend tubes (103, 104) and the lug (105) is verified and connected to the panel at one end with manual TIG joints (106). Furthermore, the collector plates (107) are welded with the lug (105) manually. The manual TIG joints (106), the lug (105) and the collector plates (107) welding undergoes local stress relieving. The panel ends are further cut to get final finished length.
[0008] The 90° bends and off-set terminal bends are prepared loose by bending in rotary bending machine and will be welded to the lug (105) attachments. The top end of the formed straight panel is cut and edge preparation is done. A fixture arrangement is prepared at the top end of the panel and is attached to panel by welding for joint feeding.
[0009] The problem with the conventional method is that aligning and manually welding the bend tubes with panel is very time consuming and more manpower is required for fit-up and welding. Since each bend is prepared by bending it in the rotary bending machine, manufacturing cycle time further increases. Moreover the manual TIG joints is used to weld the tubes and the lug to the panel and it creates unsafe working conditions for the operator.
[0010] It is thereby required to develop a method for bending tubes of a furnace side wall panels as per the required dimensions that reduces time and costs incurred in manual TIG Joints welding and at the time of bending a single tube in a rotary bending machine.
OBJECTS OF THE DISCLOSURE
[0011] It is therefore the object of the present disclosure to overcome the aforementioned and other drawbacks in prior arts.
[0012] It is a primary object of the present disclosure to provide a method for bending tubes of a furnace side wall panels as per the required dimensions.
[0013] It is another object of the present disclosure to utilize bending operation to bend the first set of tubes and eliminate the manual TIG joints involved along with the associated unsafe working conditions.
[0014] It is one another object of the present disclosure to reduce the cycle time of manufacturing by avoiding the distortion and hot correction involved and also by eliminating the requirement of localized heat treatment.
[0015] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION
[0016] 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.
[0017] Solution to one or more drawbacks of existing technology and additional advantages are provided through 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 a part of the claimed disclosure.
[0018] The present disclosure offers a solution in the form of a method for bending tubes in a furnace vertical wall side panel, the method includes setting a first set of tubes and a second set of tubes to form the vertical wall side panel, wherein the length first set of tubes are longer than the second set of tubes, inserting a bracing plate over the first set of tubes, transferring the furnace vertical wall side panel to a furnace followed by a heat treatment process and bending the first set of tubes by a bending machine.
[0019] In an aspect of the invention, the first set of tubes and the second set of tubes are arranged alternatively to each other
[0020] In an aspect of the invention, the first set of tubes accommodate 90° bends.
[0021] In an aspect of the invention, the bracing plate has a plurality of holes.
[0022] In an aspect of the invention, the the bracing plate has a definite pitch dimension.
[0023] In an aspect of the invention, the first set of tubes as a single entity is transferred for bending in the bending machine
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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
[0028] 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:-
[0029] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the present disclosure may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0030] Fig. 1 illustrates the prior art;
[0031] Fig. 2 illustrates the arrangement of first set of tubes and the second set of tubes according to the present disclosure;
[0032] Fig. 3 illustrates the bent first set of tubes according to the present disclosure;
[0033] Fig. 4 illustrates the method according to the present disclosure.
[0034] The figures depict embodiments of the present subject matter for illustration only. A person skilled in the art will easily 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.
[0035] 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.

DETAIL DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF THE PREFERRED EMBODIMENTS:
[0036] While the embodiments of the disclosure are subject to various modifications and alternative forms, a specific embodiment thereof has 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 alternatives falling within the scope of the disclosure.
[0037] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.
[0038] The invention is related to bending of tubes in a gand bending machine by arranging them in a specific manner such that they are bent as a bunch in a bending machine, thus saving time and costs.
[0039] Referring to Fig. 2, the plurality of furnace wall side panels are made of a plurality of tubes (101) and a plurality of fins (102) in a panel forming machine. The number of the plurality of tubes (101) and the plurality of fins (102) are equal and they constitute the vertical wall side panel. The plurality of the furnace vertical wall side panels are arranged in such a way that half of the vertical wall side panels constitutes the left hand side wall and the remaining half constitutes the right hand side wall.
[0040] Further, in the furnace wall side panel the plurality of tubes (101) are arranged in a such a way that there are different lengths of tubes that accommodate the panel. The plurality of tubes includes a first set of tubes (201) and a second set of tubes (202). The first set of tubes (201) are longer than the second set of tubes. The first set of tubes (201) and the second set of tubes (202) are positioned alternatively to each other from the beginning and set in the panel forming machine.
[0041] There are two types of bends, i.e. 90° bends (103) and off-set bends (104) that are implemented on the plurality of tubes (101). In the present invention, the 90° bends (103) are accommodated by the first set of tubes (201) and the off-set bends (104) are accommodated by the second set of tubes (202).
[0042] Further, a bracing plate (203) is installed on the first set of tubes (201). The bracing plate (203) is a rectangular plate and has a plurality of holes (204) that are made for inserting the first set of tubes (201). The bracing plate (203) is provided on the first set of tubes (201) such that the tubes maintain their composure and there is no deviation in the pitch that might occur at the time of bending. Therefore by inserting the bracing plate (203), the pitch of the first set of tubes (201) is maintained.
[0043] After putting on the bracing plate (203), the panel goes for stress relieving in a furnace or a Coal-Dust Fuel (CDF) furnace that is followed by a heat treatment process. Afterwards, the bending of the first set of tubes (201) is done on a bending machine also known as a gang bending machine. As the length of the first set of tubes (201) is longer than the second set of tubes (202), only the first set of tubes (201) enter the bending machine where they are given 90° bends (103) by one bending per panel.
[0044] By using one gang bending per panel to give 90° bend (103) to the first set of tubes (201) in a single step, the 90° bend (103) that were earlier done on a single tube via a rotary bending machine is getting eliminated. Moreover, there is also a 50% reduction in providing TIG joints on the first set of tubes (201) that are associated with the 90° bends (103). Significant works for joint preparation such as end cutting, edge preparation and grinding of the panel ends corresponding to 90° bends (103) along with the loose bend grinding are also eliminated.
[0045] Referring to Fig. 4, a method (400) for bending a plurality of tubes (101) in a furnace vertical wall side panel of a high pressure steam generator is provided. The method discloses a way of producing 90° bends (103) on a first set of tubes (201).
[0046] The first step (401) includes setting a first set of tubes (201) and a second set of tubes (202) on a vertical wall side panel. The plurality of tubes (101) that form a vertical wall side panel are made up of the first set of tubes (201) and the second set of tubes (202). The first set of tubes (201) and the second set of tubes (202) are arranged side by side to each other. The first set of tubes (201) are longer than the second set of tubes (202) and are arranged alternatively to one another.
[0047] The first set of tubes (201) are for accommodating 90° bends (103) and the second set of tubes are for accommodating off-set bends (104). The present invention discloses about providing 90° bends (103) to the first set of tubes (201).
[0048] Further, in the second step (402) a bracing plate (203) is inserted in the first set of tubes (201). The bracing plate (203) is rectangular and has a plurality of holes (204). The first set of tubes (201) are inserted in the plurality of holes (204) present on the bracing plate (203). The bracing plate (203) maintains the pitch of the first set of tubes (201) so that they remain rigid during the bending process.
[0049] In the third step (403), the furnace vertical wall side panel is transferred to the furnace followed by the heat treatment process.
[0050] In the last step (404), the first set of tubes (201) are sent for bending in a bending machine. The bending machine bends the first set of tubes (201) at 90° bend (103) and all of the tubes constituting the first set of tubes (201) are bent at the same time. After bending of first set of tubes (201) is done, the loose terminal bends are welded with the vertical wall side panel and then further the lug (105) is welded. The collector plates (107) are then welded to the lug (105). A local stress relieving is done for these weld joints.
TECHNICAL ADVANTAGES
[0051] With the help of the solution as proposed herein in the context of the present disclosure, one bending per panel is done. This further eliminates the rotary bending of 90° terminal bends on a single tube as it increases the cost and time for producing the vertical wall side panels.
[0052] The present disclosure also provides that due to the present arrangement, the manual TIG joints and the associated radiography test for 90° terminal bends are totally eliminated.
[0053] Lastly, the significant work required for joint preparation such as end cutting, edge preparation and grinding of the panel ends corresponding to 90° terminal bends along with the loose bend grinding is also reduced.
WORKING OF INVENTION
[0054] In the present invention, the first set of tubes (201) and the second set of tubes (202) are arranged to form a furnace side wall panel. The first set of tubes (201) have 90° bends (103). The first set of tubes (201) are inserted in a bracing plate (204) having a particular pitch dimension. The bracing plate (203) maintains the pitch of the first set of tubes (201). The furnace vertical wall side panel is further sent to the furnace followed by the heat treatment process. Afterwards the first set of tubes (201) are sent for bending in the gang bending machine. The bending machine eliminates the extra work of attending to a single tube at a time and bends a bunch of tubes in a single action.
TEST RESULT
Comparative Benefits
Before After
1 Rotary bending of all 90° terminal bends is required (around 350 bends per PGMA) Eliminated rotary bending of 90° terminal bends by one gang bending per panel
2 Cutting of tubes as per length, edge preparation and movement of loose tubes for bending of 90° terminal bends is involved. Eliminated the activity for 90° terminal bends.
3 Manual TIG joints of 90° terminal bends and the associated RT (around 350 TIG joints per PGMA) is involved. The manual TIG joints and the associated RT for 90° terminal bends are totally eliminated.
4 Significant works for joint preparation such as end cutting, edge preparation and grinding of the panel ends corresponding to 90° terminal bends along with the loose bend grinding. Eliminated the activity.
5 Ensuring and maintaining the individual pitch dimension of terminal bends during joint feeding and welding is time consuming. Gang bending is done after inserting bracing plates of the required pitch at the tube ends, hence individual pitch verification is avoided.
6 Average time required for preparation, joint feeding and welding for 90° terminal bends = 28 hrs Average time required for correction, marking and Gang bending process of 90° terminal bends = 9 hrs

[0055] 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 particular claim containing such introduced claim recitation to disclosures 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. Also, 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 analogous to “at least one of A, B, and C, etc.” is used, in general, such 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 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.”
[0056] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present disclosure contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the disclosure, and other dimensions or geometries are possible. Also, while a feature of the present disclosure may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present disclosure. The present disclosure also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.
[0057] 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.
[0058] 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.
[0059] 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”.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] 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.