Claims:WE CLAIM :

1. A method of machining of Seven Holes Venturi Nozzle for a Steam Generator, wherein
- one hole is placed on centre of forging and other plurality of holes are located around the centre hole, in which each hole has a smaller length converging regions of circular cross section (P), smaller length of Throat (Q) and longer diverging region in circular cross section (R) with smooth radii at intersect regions, and the concave grooves are placed on outer surface (S) Venture nozzle; the method comprising the following steps:
- the holes are done by Deep hole drilling process;
- the converging regions, smaller length of Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are done by boring and profile machining process.

2. The method as claimed in claim 1, wherein the drilling, boring and profile machining are carried out at speed of 300 to 600 rpm, feed of 40 to 120mm/minute and depth of cut of 0.1 to 1mm.
, Description:“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 Seven Holes Venturi nozzle is used as the flow limiters in the steam pipe which does not produce pressure fluctuations resulting steam pipe vibrations.

BACKGROUND ART/ PRIOR ART 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] As per Steam Generator design requirements, the Seven Holes Venturi addition in Steam outlet nozzles is a new requirement. Purpose of Venturi Nozzle is to limit the steam flow to an acceptable level during an anticipated break of a steam line. As the pressure loss of such flow limiters (Venturi Nozzle) must be minimized during normal operation their design is similar to that of Venturi nozzle. The Venturi Nozzle is a circular shape solid heavy forging. It has 7 (seven) number of holes which are located in circular pitch Pattern. Each hole has a smaller length converging regions in circular cross section, smaller length of Throat and longer diverging region in circular cross section with smooth radii at intersect regions. Also, it has concave shape grooves on outer surface of nozzle.

[004] In available similar methods of machining, process used was a combination of conventional drilling and forming tools for taper profile machining.

[005] The above methods of machining have been resulted in a poor surface finish, less accuracy and more manufacturing time.
[006] In view of the above, the present invention has been introduced, which can obviate shortcomings of the prior art(s) and serve the purpose effectively.

OBJECTS OF INVENTION:
[007] It is therefore an object of present invention to provide a method of machining of Seven Holes Venturi nozzle for a Steam Generator, wherein machining of seven holes venture is carried out from circular shape heavy solid forging.

[008] Another object of the invention is to provide a method of machining of Seven Holes Venturi nozzle for a Steam Generator, which overcomes drawbacks of the prior art(s).

[009] Still another object of the invention is to provide a method of machining of Seven Holes Venturi nozzle for a Steam Generator, which is simple.

[0010] 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:
[0011] 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.

[0012] The Venturi Nozzle hole has seven numbers of holes that are located in circular pitch pattern. Initially, the pilot holes are done by deep hole drilling process. Subsequently, the converging regions, smaller length of Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are conducted by boring and profile machining process.

[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 shows: Section — BB illustrates sectional front view Venturi Nozzle of the present invention.
Figure 1 shows: View — A illustrates side view of Venturi Nozzle according to the 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 a technology pertaining to a method of machining of Seven Holes Venturi nozzle for a Steam Generator.

[0020] Now, reference may be made to Figure 1 indicating an exemplary embodiment of the present invention without restricting scope of the invention to the same. As shown in Figure 1, the Venturi Nozzle has seven numbers of holes on its face. As per Venturi nozzle design, one hole placed on centre of forging and other plurality (6Nos) of holes are located around the centre hole. Each hole has a smaller length converging regions in circular cross section (P), smaller length of Throat (Q) and longer diverging region in circular cross section (R) with smooth radii at intersect regions. The concave grooves are placed on outer surface (S) Venture nozzle.

[0021] The complete machining of Seven Holes Venturi Nozzle is carried out through combination of Deep hole drilling process, boring process, profile machining process using Horizontal drilling and Boring machines.

[0022] Initially, the seven holes are done by Deep hole drilling process. Subsequently, the converging regions, smaller length of Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are done by boring and profile machining process.

[0023] Deep hole drilling processes are manufacturing processes for the machining of bore holes with diameters between D = 0.2... 2000 mm and whose drilling depth is usually greater than three times the diameter.

[0024] 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.

[0025] 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.

[0026] The process of drilling, boring and profile machining are known particularly to a person skilled in the art. Hence, the same is not further discussed here.

[0027] In present invention, the pilot holes are done by a deep hole drilling process which ensured the hole straightness within the range of 0.1 to 0.5mm in the length of 650 to 750mm. Subsequently, the converging regions, smaller length of the Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are done by boring and profile machining process using CNC machines.
[0028] The machining parameters such as speed, feed and depth of cut are selected suitably to meet the material hardness and to ensure the required surface finish of for example 1.6?m. The parameters are as follows:
- Speed (300 to 600 rpm)
- Feed ( 40 to 120mm/minute)
- Depth of cut (0.1 to 1mm)

[0029] The seven hole venturi is a heavy forging of 650 to 750mm length and making a deep hole in the forging within the range of 0.1 to 0.5mm hole straightness through conventional drilling process is very challenging one.

[0030] In instant invention, the pilot holes are done by a deep hole drilling process which ensured the hole straightness within the range of 0.1 to 0.5mm in the length of 650mm to 750mm. Subsequently, the converging regions, smaller length of the Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are done by boring and profile machining process using CNC machines.

[0031] The total time taken for complete machining is very less as compared to any other process.

WORKING EXAMPLE

[0032] The method of machining of Seven Holes Venturi Nozzle for a Steam Generator comprising the following steps:
- the holes are done by Deep hole drilling process;
- the converging regions, smaller length of Throat and longer diverging with smooth radii at intersect regions and concave grooves on the outer surface are done by boring and profile machining process.

[0033] The drilling, boring and profile machining are carried out at speed of 500 rpm, feed of 70mm /minute and depth of cut of 0.4 mm.

[0034] 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.

[0035] 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.

[0036] 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”.

[0037] 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.
[0038] 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.

[0039] 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.

[0040] 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.