Claims:WE CLAIM:

1. A set-up for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces comprises a centering bolt (1) passing through sacrificial bearing/ tandem aligned bearings (2) and is integrated with the tool mounting collet (3) by a fastener (4), wherein a polishing tool (6) is inserted in the slot provided in the collet (3) over which the mechanism housing provision for tool adjustment (6) is slid over.

2. The set-up as claimed in claim 1, wherein the fastener is lock nut (4).

3. The set-up as claimed in claim 1 or 2, wherein the arrangement of centering fixture is integrated with the polishing tool (6) is mounted on to a portable rotary machine (5) and aligned with the inner diameter of the tube (7) from the bundle of tubes, protruding outside the tube sheet plate (8).

4. The set-up as claimed in claims 1-3, comprising a single/double arm with provision to vary the applied pressure on the tool (6) for polishing, alternatively a continuous, axis symmetrical arm resembling a cylinder, that holds the polishing tool (6).

5. The set-up as claimed in claims 1-3, comprising a single/double arm without provision to vary the applied pressure on the tool (6) for polishing, alternatively a continuous, axis symmetrical arm resembling a cylinder, that holds the polishing tool (abrasive sheet).

6. The set-up as claimed in claims 1-3, wherein the double arm Two-point tool (6) is provided to prevent bending of tool mount when the tool head’s length is adjusted during the operation due to the reaction forces arising due to machining.

7. The set-up as claimed in claims 1-3, wherein the multi-point tool (6) is provided to maintain a circumferential contact through wrapping of tool over tube.

8. Method for inner diameter (ID) centered polishing of tube ends in tube bundles at confined spaces comprises following steps:
- jig/set-up is aligned with the inner surface of tube using the sacrificial bearings (2);
- for polishing, grade is inserted in the collet (3);
- the depth of polishing is adjusted using the provision in the collet (3);
- the rotary machine is operated and the tube is polished evenly on the outer surface by maintaining concentricity with the inner surface of tube;
- the dimensions are checked in between to meet the dimensional tolerances, and stopped appropriately;
- If the dimensional tolerances are met, the jig/set-up is retracted.
, Description:‘SET-UP AND METHOD FOR INTERNAL DIAMETER CENTERED, OUTER DIAMETER POLISHING OF TUBE ENDS IN TUBE BUNDLES’

FIELD OF THE INVENTION:
[001] The present invention relates to an arrangement, compatible with all hand-held rotary mechanisms with the purpose of the arrangement to carry out ID centered, OD polishing of tubes. The invention is to address the present difficulty in polishing the tubes in an assembly of tube bundle at confined spaces; that does not allow for tubes to be rolled.
[002] The invention in particular is directed to a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces. The set-up is compatible with all portable rotary machines.

BACKGROUND OF THE INVENTION/PRIOR ART:
[003] 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.

[004] Among the principles of heat exchanger design, shell and tube heat exchanger is an efficient and compact arrangement. The prominent difficulty associated with shell and tube design is the separated existence of tube and shell side fluid achieved by the use of collectors or headers. These components are to be welded with the tube bundles assembled inside the tube sheet. To avoid corrosion and to result in a light weight model, exotic materials are used for the tube sheet design. But, the selection of exotic materials demands for stringent prerequisites in the surface finish at the ends of the tubes present in the tube bundles.

[005] To polish the outside diameter of the end of the tubes, assembled inside the tube sheet design; polishing is done manually resulting in extended preparation time. Also, the surface finish is dictated by the uniformness of pressure offered by the operator’s hand over the abrasive sheet. This method is replaced by a centerless orbiting manual technique using a hand held, centerless buffing tool resulting in inaccurate and uneven machining of the outer diameter (OD) surface, thus not meeting the prerequisites levels.

[006] In this methodology, the inner surface of the tube is taken as reference and the tool is aligned with the axis of the tube by a centering fixture, that is coupled along with the jig. The centering fixture, either revolves relative to the tube or jig or both but never exceeds the revolution of the jig where the polishing tool is mounted. Thus, the need for development of a jig for ID centered polishing of outer surface of tube ends, justified. Hence, the present invention has been introduced.

PRIOR ART:
[007] Chinese patent CN201960410U (automatic steel tube polishing machine) describes the method for automatically polishing steel tubes but differs from the present invention completely. This method does not claim interchangeability and claims to be dependent on walking turning rolls with an inductive switch only for limiting the dimensions, but the swing arm be manually driven and adjusted due course, during the polishing to achieve equal material removal through polishing the outer surface.
[008] Chinese patent CN202137673U (Steel pipe polishing device) describes the method for polishing steel pipes but differs in entirety from the present invention. This method demands for a platform over which polishing mechanism is arranged at one end of the supporting device which travels throughout the entire length of the tube. The method will not address the present scenario where the assembled tubes require polishing of outer surface be concentric.
[009] Chinese patent CN204843802U (Novel high-efficient Steel pipe polishing and grinding machine) describes a novel method for polishing and grinding steel pipes but differs from the present invention in full. This methodology has two guiding arms (top and bottom between which the tube sample that needs polishing is to be introduced. Polishing over the entire outer surface is made through manual movement of the total set up all around the tube sample (in an assembled tube bank). This rotation of the entire setup around the tube in an assembly is restricted by the adjacent tubes. Hence, this method could not be used for polishing the ends of tubes in an assembled tube bundle. Also, the polishing is limited to the width of the flexible grinding sheet.
All the aforementioned patents lack the following:
1. Centerless polishing machine for entire OD.
2. Centerless polishing machine for desired portion of outer surface.
3. To address their ability to polish tubes in a closely spaced assembly with outside diameter of tubes less than 15mm and pitch less than 10 mm.
4. To address its ability in maintaining the concentricity with the inner surface (ID) of the assembled tubes in achieving the required finish during online operation.
5. To address the mechanism used for aligning the polishing tool w.r.t. inner surface (ID).
6. To address the integration of centering fixture and polishing tool in a simplified mount that is interchangeable with all hand held rotary machines.
7. To address the issue of bending during the use of single point tool due to machining induced reaction forces, when the tool head’s position is adjusted during the operation.

OBJECTS OF THE INVENTION:
[0010] An object of the invention is to provide a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces, which obviates shortcomings of the prior art(s) and is simple in construction.

[0011] Another object of the invention is to provide a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces, which results in high degree of surface finish and concentric with the internal diameter surface of the tubular component.
[0012] Yet another object of the invention is to provide a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces, which has flexibility in adapting to the dimensions of the tubular component.
[0013] Still another object of the invention is to provide a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces, in which the set-up has interchangeability between a wide range of portable rotary machines.
[0014] 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:
[0015] 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.

[0016] According to the invention, the technique for achieving coaxial alignment is the centering, shaft mounted over the centering bolt. The bolt may or may not confine the revolution of the sacrificial shaft or tandem bearing. The centering bolt, but forms an integral part with the tool holding collet, thus when mounted on any portable rotary machine, enables the tool holder to revolve along with the shank of the entire jig.

[0017] Without the fixture for coaxial alignment of the tool with the inner surface of the tube, the polishing of Outer surface of the tube at the ends may result in an eccentric surface and the eccentricity being dictated by the forces exerted by the operator. The jig being guided during the rotary motion removes the surficial layers of the outer surface of the tube based on the position of the tool. The position of the tool is either constantly pressurized against the work piece or set to a predetermined depth. With the former method, intermediate intervention and control of dimensions is required, to avoid excessive removal of material. While the later method adopted provides a continuous and gradual adjustments as the tool is fed in the direction of polishing (axis of tube).

[0018] The fixture provides easy provisions for changing the worn out tool, post-polishing multiple specimens. The shank extends beyond the centering shaft, after forming an adjustable but integral part with the tool holding collet during and after polishing, held by the chuck of any portable rotary machine.

[0019] The centrifugal forces acting on the jig design, trying to rip open the split design of the jig is sustained by an external collet which has provisions to adjust depth of cut of tool, pressure on work piece and to protect the collet in maintaining parallelism with the inner surface of the tube against the centrifugal forces.

[0020] 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.

[0021] 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.

[0022] 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:
[0023] 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:-

[0024] Figure 1 shows: Schematic representation of Centering fixture integrated with jig (set-up) for polishing ends of smaller diameter tube to perform centered polishing process after aligning with the tube Inner surface according to the invention.

[0025] 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 A PREFERRED EMBODIMENT OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:
[0026] 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.

[0027] The present invention makes a disclosure regarding a technology pertaining to a set-up and method for internal diameter centered, outer diameter polishing of tube ends in tube bundles at confined spaces.

[0028] According to the invention, the technique is for carrying out polishing of outer surface in reference to the inner surface. This operation is mandated to maintain surface finish prior to welding of bank tubes pertaining to a tube – shell heat exchanger with the collection header’s stub using fillet joint. This process offers the mandated surface finish, coaxially, maintaining concentricity with inner surface for the desired length from tube end. The process of aligning with the axis of the tube is performed using a centering sacrificial shaft or bearings in tandem. The centered polishing is carried by a fixture and jig combined to form an integral set up that is interchangeable with all portable rotary machines by holding the centering shaft extending beyond the collet holding the tool.

[0029] Now, reference may be made to Figure 1. The centering bolt of the entire assembly (1) passes through the sacrificial bearing or tandem aligned bearings (2) and is integrated with the tool mounting collet (3) by a lock nut (4). A polishing tool (6) is inserted in the slot provided in the collet (3) over which the mechanism housing provision for tool adjustment (6) is slid over. This arrangement of centering fixture integrated with the polishing tool is mounted on to a portable rotary machine (5) and aligned with the inner diameter of the tube (7) from the bundle of tubes, protruding outside the tube sheet plate (8).

[0030] The present invention involves semi-automatic process for outer diameter polishing of tube ends.

Features of the Invention:
1. A centering fixture in the form of sacrificial cylinder with very low coefficient of friction or an arrangement of ball bearing arranged in tandem with outer diameter altered to match the inner diameter of tube that needs to be outer diameter polished, without clearance with the centering bolt.
2. A single or double arm design with provision to vary the applied pressure (eg. Spring, pre-tensioning, etc.) on the tool (6) for polishing or a continuous, axis symmetrical arm resembling a cylinder, that holds the polishing tool.
3. A single or double arm design without provision to vary the applied pressure on the tool (6) for polishing or a continuous, axis symmetrical arm resembling a cylinder, that holds the polishing tool (abrasive sheet).
4. The integrating and aligning mechanism couples the centering fixture and the polishing jig.
5. The interchangeable mechanism facilitates adaptability between wide variety of portable rotary machines.
6. The methodology used to hold the tool (connection between jig and tool) either by a compliant mechanism using stiff bent rods or outer collet with studs for tightening to sustain centrifugal forces acting on the split design of jig.
7. The methodology used for fine variation (advancement of tool) in the outside diameter of the tube, based on the requirements (both in the axial and radial direction).
8. Centered polishing machine for entire outer diameter of the desired portion of outer surface.
9. Ability to accomplish the polishing in a closely spaced assembly.
10. Ability to polish tubes with all magnitudes of diameters and especially with tubes less than 15mm.
11. Double arm Two-point tool (6) prevents bending of tool mount when the tool head’s length is adjusted during the operation due to the reaction forces arising due to machining.
12. Multi-point tool (6) maintains a circumferential contact through wrapping of tool over tube.
13. Stationary power source and orbital movement of tool with respect to the tube even when the tubes are closely packed (separated by a distance, as small as 10mm surface to surface)
14. Maintaining higher surface finish due to the nature of removal of tool by abrasion.
15. Auto-alignment of tool and application of uniform pressure on the tube.
16. Rapid replacement of tool to increase productivity.

ADVANTAGES:
[0031] The main advantage of the tool is its ability to polish after maintaining concentricity with the inner surface, enabled by automatic centering of the integral fixture cum jig with the tube’s inner surface. Centering fixture integrated with the jig for polishing is mounted in a rotary actuator and positioned using the fixture. With the rotary motion actuated, the polishing is performed.
[0032] The notable advantages are the auto alignment capability with centered polishing of outer surface of closed spaced tubes ends, with power source interchangeability amongst portable rotary machines. Other advantageous abilities are its ability to result in varied outside diameter outputs and rapid replacement of tool.

WORKING OF INVENTION:
[0033] Method for inner diameter (ID) centered polishing of tube ends:

[0034] For polishing tubes that are already assembled the following steps are performed:

1. The jig/set-up is universally compatible with industrial grade portable rotary machine.
2. The entire jig/set-up is aligned with the inner surface of tube using the sacrificial bearings (2).
3. For polishing, appropriate grade is inserted in the collet (3).
4. The depth of polishing is adjusted using the provision in the collet (3).
5. The rotary machine is operated and the tube is polished evenly on the outer surface by maintaining concentricity with the inner surface of tube.
6. The dimensions are checked in between to meet the dimensional tolerances, and stopped appropriately.
7. If the dimensional tolerances are met, the jig/set-up is retracted completely.

TEST RESULT:
[0035] The test has been conducted and the results are found to be satisfactory.

[0036] 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.

[0037] 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.

[0038] 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”.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.