Claims:WE CLAIM

1. A method of machining of Seven Holes Venturi Nozzle for a Steam Generator comprising steps of:
- preparing pilot holes by thermal cutting process, keeping the machining allowance from 10 to 15mm around the hole inside;
- carrying out the balance machining through combination of circular boring process with the help of single point tool and uniform angular profile milling by shoulder milling cutter using CNC Horizontal Boring Machine;
wherein in the boring process, the tool is rotated about the hole centre, and the uniform angular profile machining is done by the shoulder milling cutter, in which the cutter rotates perpendicular to the shell longitudinal axis and at the same time, the cutter moves towards the shell longitudinal axis.

2. The method as claimed in claim 1, wherein the parameters for the machining process (Boring and angular profile milling) including speed, feed and depth of cut are suitable to meet the material hardness and to ensure the required surface finish of about 1.6?m.

3. The method as claimed in claim 1 or 2, wherein the Speed, feed and Depth of cut are 600 to 800 rpm,0.2 to 1mm/minute and 0.1 to 1mm respectively.

4. The method as claimed in claims 1-3, wherein any size of hole with a uniform angular profile can be made on the Shell outer surface.
, Description:This application is modification/improvement of the main application number 202131011743 of 19.03.2021

Title: A method of machining of Seven Holes Venturi Nozzle
for a Steam Generator

FIELD OF INVENTION:
[001] This invention relates to a method of machining of Seven Holes Venturi Nozzle for a Steam Generator. The hole is made with uniform angular profile machining in the thick cylindrical forged shell by Horizontal Boring machine. In any type of Steam Generators, Heat Exchangers and Pressure Vessels, there are multiple nozzles / opening in the outer surface of cylindrical shell (Pressure boundary). These nozzles are used to connect the inlet, outlet pipe lines, Hand holes covers and Manholes doors. These nozzles are integrated with cylindrical shell by welding. A hole with uniform angular profile is required to facilitate a nozzle welding.

BACKGROUND OF INVENTION/PRIOR ART:
[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] As per Steam Generator, Heat Exchangers and Pressure Vessels pressure boundary design requirements, the nozzles to be integrated is by set-in type welding. For set-in nozzle welding, the hole to be made in the cylindrical shell is in such a way to have the circular shape in longitudinal direction and elliptical shape in circumferential direction. To facilitate the weld electrode approach to the root of weld joint, uniform angular profile will be made in circular shape portion as well as elliptical region portion.

[004] In existing practices, the most of the fabrication industries the circular profile weld edge with uniform angular profile on cylindrical surface is done by thermal cutting to the possible size and the balance is done by manual hand grinding. The uniform angular profile grinding manually is very tough and time consuming process and also the grinding surface is not uniform.

[005] In view of the above, the present invention has been proposed, wherein the complete hole with angular profile machining in the thick cylindrical forged shell is successfully established by Horizontal Boring machine.

OBJECTS OF INVENTION:
[006] An object of present invention to provide method of machining of Seven Holes Venturi Nozzle for a Steam Generator, which makes hole with uniform angular profile machining on thick cylindrical forged Shell, in which any size of hole with a uniform angular profile can be made on the Shell outer surface.

[007] Another object of the invention is to provide method of machining of Seven Holes Venturi Nozzle for a Steam Generator, which avoids the uniform angular profile grinding by manual method.

[008] Yet another object of the invention is to provide method of machining of Seven Holes Venturi Nozzle for a Steam Generator, which is simple.
[009] 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:
[0010] 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.

[0011] In any type of Steam Generators, Heat Exchangers and Pressure Vessels, there are multiple nozzles / opening on outer surface of cylindrical shell (Pressure boundary). These nozzles are used to connect the inlet, outlet pipe lines, Hand hole covers and Manhole doors. These nozzles are integrated with cylindrical shell in set-in type welding. For set-in nozzle welding, the hole to be made in the shell in such a way that the circular shape in longitudinal direction and elliptical shape in circumferential direction are obtained. To facilitate the weld electrode approach to the root of weld joint, uniform angular profile is made in hole (circular shape portion and elliptical shape portion). The complete machining is done through combination of circular boring process with help of single point tool and uniform angular profile milling by Shoulder milling cutter using Horizontal Boring machine.

[0012] In the boring process, the tool rotates about the nozzle hole centre. Whereas, the uniform angular profile by Shoulder milling cutter rotates perpendicular to Shell longitudinal axis and same time, the cutter moves towards Shell longitudinal axis. By this process, any size of hole with angular profile machining can be made on the Shell outer surface.

[0013] 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.

[0014] 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.

[0015] 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 :
[0016] 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: Isometric view of Forged Shell with holes.
Figure 2: Sectional view to indicate the Section-EE & DD.
Figure 3: Section-EE indicates the circular shape portion with uniform angular profile of the present invention.
Figure 4: Section-DD indicates the elliptical shape portion with uniform angular profile according to the present invention.
Figure 5: Isometric view of machining completed hole in accordance with present invention.

[0017] 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 THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF PREFERRED EMBODIMENTS :

[0018] 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.
[0019] The present invention makes a disclosure regarding an invention pertaining to method of machining of Seven Holes Venturi Nozzle for a Steam Generator.

[0020] Reference may be made to Figure 1, wherein the cylindrical shell with nozzle welding holes is shown in Isometric view. The nozzles are integrated with cylindrical shell in set-in type welding. For set-in nozzle welding as shown in Figure 2, the hole is to be made in the shell in such a way that the circular shape with uniform angular profile in longitudinal direction (A & B of Section-EE, Figure 3) and elliptical shape with uniform angular profile in circumferential direction (C & D of Section-DD, Figure 4) are obtained.

[0021] The complete machining is conducted through combination of circular boring process with the help of single point tool and uniform angular milling by Shoulder milling cutter using Horizontal Boring machine (best seen in Figure 5).

[0022] Boring is a cutting process that involves the use of a single-point cutting tool or boring head to enlarge an existing hole in a work piece. Boring processes are typically performed using a lathe, milling machine or a horizontal boring mill.

[0023] Profile milling is used to rough or finish mill vertical or slanted surfaces. The surfaces selected must allow for a continuous tool path. The depth of the cut can be specified using the STEP_DEPTH parameter. To just make one profile pass around the part at full depth, STEP_DEPTH is greater than part thickness.

[0024] The process of boring and profile machining are known particularly to a person skilled in the art. Hence, the same is not further discussed here.

[0025] In the boring process, the tool rotates about the nozzle hole centre. Whereas, during the uniform angular profile machining by Shoulder milling cutter rotates perpendicular to shell longitudinal axis and at the same time, the cutter moves towards shell longitudinal axis.

Method of making hole with uniform angular profile machining in the thick cylindrical forged shell for Steam Generator is as follows:

[0026] In the present invention, the pilot holes are done by manual thermal cutting process, keeping the machining allowance from 10 to 15mm around the hole inside. Subsequently, the balance machining is done through combination of circular boring process with the help of single point tool and uniform angular profile milling by shoulder milling cutter using CNC Horizontal Boring Machine.

[0027] In the boring process, the tool is rotated about the hole centre. In contrast, the uniform angular profile machining is done by the shoulder milling cutter and the cutter rotates perpendicular to the shell longitudinal axis and at the same time, the cutter moves towards the shell longitudinal axis.

[0028] For the machining process (Boring & angular profile milling), the parameters including speed, feed and depth of cut are selected suitably to meet the material hardness and to ensure the required surface finish of about 1.6?m.

The parameters are as follows:
Speed : 600 to 800 rpm
Feed : 0.2 to 1mm/minute
Depth of cut: 0.1 to 1mm

Test result/Advantageous features
[0029] In existing practices in most of the fabrication industries, the circular profile weld edge with a uniform angular profile on cylindrical surface was done by thermal cutting to the possible size and the balance was done by the manual hand grinding. The uniform angular profile grinding by manual is very tough and time consuming process and also the grinding surface is not uniform.

[0030] In the present invention, the complete hole with angular profile machining in the thick cylindrical forged shell was successfully established by CNC Horizontal Boring machine. In this process, any size of hole with angular profile machining can be made on the shell outer surface.

Working of the Invention
[0031] By the invention, the complete machining of nozzle welding holes with angular profile machining is conducted through a combination of circular boring process with the help of single point tool and uniform angular profile milling by Shoulder milling cutter using Horizontal Boring machine.

[0032] In the circular boring process, the single point tool is rotated about the nozzle hole center.

[0033] In the elliptical shape machining process, the Shoulder milling cutter rotates perpendicular to the shell longitudinal axis and the same time, the cutter moves towards shell longitudinal axis.

[0034] In this process, any size of hole with a uniform angular profile can be made on the Shell outer surface.

[0035] 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.

[0036] 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.

[0037] 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”.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.