Description:TECHNICAL FIELD
[0001] The present disclosure, in general, relates to the design and manufacturing Universal Edge Preparation Tool for stubs of headers used in the high-pressure high-temperature steam generator. More particularly the present invention relates to designing of single edge preparation tool for machining stubs of F 76.20 mm to F 31.08 mm with variable thickness in Semi Gantry Radial Drilling Machine. Moreover, the present invention discloses the method of using the single tool to edge prepare tubes of different diameters and thickness of stubs used in headers.
BACKGROUND
[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] Nowadays, high pressure and high-temperature steam generators are used for power generation, in which the evaporator panels are connected to headers and coils through stubs.
[0004] During the construction of the headers, different types of connections are required comprising different diameters and different thicknesses of stubs per boiler. In the manufacturing of the headers with stubs, the stubs are edge prepared for machining the connecting tubes of panels and coils through conventional means of form tool mounted in semi gantry radial drilling machine.
[0005] Moreover, there is a need for the change in the tool holder and the tool with each change in the required diameter and required thickness of stubs. The supercritical boiler technology has introduced the use of high wall thickness; hence, the stubs used in headers are with high wall thickness leading to the requirement of more cutting length inform tool and tool breakage due to heavy load.
[0006] Due to the higher thickness of stubs, the inner diameter becomes very minimum; this, in turn, contributes to the breakage of the tool holder. The outside diameter of the stubs ranges from F 76.20 mm to F 31.8 mm with variable thickness. The quantum of stubs per header starts from approximately 150 stubs per header to 1200 stubs per header.
[0007] Due to the frequent change in the requirement of a wide range of stub diameter and thickness leads to the formation of excessive inventory of form tools and tool failure increases with increasing stub thickness.
[0008] The present invention deals with the solution to the above problem by providing the Universal edge preparation tool for semi gantry radial drilling machine for machining of header stub end with outside diameter ranges from F 76.20 mm to F 31.8 mm having varying tube thickness, that eliminates the inventory of form tools with varying range of stub thickness and increasing the capacity to machine stubs having higher chamfering length.
[0009] Moreover, the present invention also provides a solution for ever increasing demand for high grade cutting tools by introducing the option to use grade-specific inserts for new alloy tubes and thus overcoming the limitation in the performance of form tools.
[0010] Additionally, the present invention provides a single tool holder for semi gantry radial the drilling machine, which facilitates in easy replacement of tools with a varying change in the thickness of stubs.
[0011] Furthermore, the present invention also discloses the method utilized by the universal edge preparation apparatus for interconnecting stubs in the header of the steam generator.
SUMMARY
[0012] This summary is provided to introduce concepts related to provide the Universal edge preparation tool for semi gantry radial drilling machine for machining of header stub end with outside diameter ranges between F 76.20 mm to F 31.8 mm having varying tube thickness by eliminating inventory of form tools with varying range of stub thickness and increasing the capacity to machine stubs with higher chamfering length.
[0013] The present disclosure defines a universal edge preparation apparatus for interconnecting stubs in header of the steam generator, the universal edge preparation apparatus comprising: a tool holder made of high thickness treatable rod, wherein the dimension of the morse taper of the tool holder is maintained as per the machine requirement, a plurality of guideways milled on the base of the tool holder, wherein the guideways are identical and milled opposite to each other with respect to a centerline, a plurality of slide blocks accommodated inside the plurality of guideways wherein, the threaded holes are configured on the guideways to accommodate the respective slide blocks, and a plurality of adjustable cartridges configured by machining rod with heat treatable properties, wherein, the plurality of adjustable cartridges are introduced to the slide blocks with the help of a grub screw
[0014] In an embodiment, the present disclosure discloses the tool holder that is positioned on the mounting of a semi gantry radial drilling machine.
[0015] In an embodiment, the present disclosure defines the base of the tool holder is provided with a center hole that accommodates the center pin.
[0016] In an embodiment, the present disclosure defines the base of the tool holder that is provided with a plurality of counterbored through-hole provided across the diameter of the base of the tool holder.
[0017] In an embodiment, the present disclosure defines a plurality of locking pins that are inserted through the plurality of the counterbored through-hole to hold the center pin in position.
[0018] In an embodiment, the present disclosure defines the slide blocks that are provided with mounting holes to accommodate the stem of the plurality of the adjustable cartridges.
[0019] In an embodiment, the present disclosure defines the slide blocks that are provided with a tapped hole to hold the adjustable cartridges with a grub screw.
[0020] In an embodiment, the present disclosure defines the head of the adjustable cartridge of the tool holder that accommodates the suitable carbide inserts.
[0021] In an embodiment, the present disclosure defines a methodology utilized by universal edge preparation apparatus for interconnecting stubs in header of the steam generator, the method comprising mounting of the carbide inserts on the adjustable cartridges wherein the carbide inserts are of suitable grade that matches to the material of the header stub, securing the position of carbide inserts on the adjustable cartridges through self-locating seating fastened by the screws, inserting the adjustable cartridges to the slide blocks and fastened with grub screws, mounting the cartridges along with carbide inserts on the guideways provided at the base of the tool holder, positioning the cartridges along with carbide inserts with grub screws on the guideways of the tool holder, wherein the positioning depends upon the length of the chamfering to be machined, and positioning of the tool holder on the mounting of the semi gantry radial drilling machine.
[0022] In an aspect, the present disclosure defines the Machining (Edge preparation) of header stub in semi gantry radial drilling machine is done with a pre-positioned header with welded stubs in the semi gantry radial drilling machine with the help of V-Blocks.
[0023] In an aspect, the present disclosure defines the designed tool holder having a suitable matching Morse taper that is fitted to the machine with adjustable carbide insert cartridges.
[0024] Moreover, the present disclosure defines the tool holder that is fitted with the guide pin suiting the inner diameter of the header stub. The tool holder is lowered for the guide pin to enter the inner diameter of the tube and locate properly the tool holder to the center.
[0025] Furthermore, the present disclosure defines the adjustable carbide insert cartridge that two in number and are positioned to cover the chamfering length simultaneously when feed is given. The edge preparation is controlled with the machining parameters fed into the semi gantry radial drilling machine to produce a smooth prepared edge at the stub end and the chamfering length is controlled by the feed of machine.
[0026] Specially machined tool holder with integral features, adjustable carbide insert cartridge and guide pin suitable to the matching inner diameter of the stub remains connected to the machine and the tool is again engaged with the next header stub in the row for edge preparation.
[0027] Moreover, the operation is continued depending upon the number of rows of header stubs is available. The cutting tool needs not to be changed if the same header is having a different diameter of stub and thickness. The end machining of stub can be continued with the change of guide pin suiting the inner diameter of the new header stub. Thus, with a single tool, the edge preparation of header stub in semi gantry radial drilling machine is carried out for any diameter of the stub irrespective of thickness and thus results in saving manpower, material, and cost.
[0028] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] 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 methods that are consistent with the subject matter as claimed herein, wherein:
[0030] Fig. 1 illustrates a schematic diagram of the designed Tool Holder with an illustration of Front, Top, and Side view of the tool holder in accordance with an embodiment of the present invention;
[0031] Fig. 2 illustrates the structure of an adjustable cartridge, in accordance with an embodiment of the present invention;
[0032] Fig. 3 illustrates the structure of a center pin, in accordance with an embodiment of the present invention;
[0033] Fig 4 illustrates a structure of locking pin, in accordance with an embodiment of the present invention;
DETAILED DESCRIPTION
[0034] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0035] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. In addition, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0036] The present disclosure aims to solve the technical problem of machining of header stub end with outside diameter ranges between F 76.20 mm to F 31.8 mm having varying tube thickness by providing the Universal edge preparation tool for semi gantry radial drilling machine.
[0037] Fig.1 shows the front (R), top (Q) and side (S) views of the tool holder (102). Fig. 1(a) shows the front view of the tool holder (102). The tool holder (102) is fabricated by machining of high thickness heat treatable rod.
[0038] Fig. 1(b) shows the rear view of the tool holder (102) that maintains the Morse taper (104) of the tool holder (102) attached to the semi gantry radial drilling machine to edge prepare the header stub with outside diameter range F 76.20 mm to F 31.8mm irrespective of thickness. The tool holder (102) has guideways (106a, 106b) milled on the base of the tool holder (102). On the bottom of the tool holder (102), the base bears a center hole [114] to accommodate the center pin (116). The base of the tool holder (102) is provided with counter bored through hole (118a, 118b) across its diameter. The plurality of locking pins are inserted through this plurality of counter bored through hole (118a, 118b) to hold the center pin in position. The slide blocks (110a, 110b) are provided with a mounting hole suiting the dimensions of the stem of the adjustable cartridge.
[0039] Moreover, Fig.1 (c) shows the side view of the tool holder (102) in accordance with the embodiment of the present invention. The guideways (106a, 160b) are identical and are milled opposite to each other with respect to the centerline. Additional guideways are also provided on both sides of the centerline. The slide blocks (110a, 110b) are designed with dimensions to suit the guideway (106a, 106b) dimensions. Both side guideway (106a, 106b) bears the threaded hole for holding slide blocks (110a, 110b). Fig. 1(d) and Fig. 1(e) shows the front view and top view of the slide blocks respectively.
[0040] The tool holder (102) is positioned on the mounting of the semi gantry radial drilling machine. The holder is matched to the Morse taper in the holding post of the machine. The semi gantry radial machine extended arm is positioned over the pre-loaded header with stubs. The tool holder (102) is positioned to match the axis of the stub hole and locked at the position. The tool holder (102) is lowered for the center pin to enter the stub inner diameter until the carbide inserts are engaged with the tube, ensuring the proper positioning and alignment with the header stub during machining. The header stub to be machined is marked for the final length required after chamfering.
[0041] Both the adjustable cartridges are first mounted with the carbide inserts with the suitable grade as per the material of the header stub to be machined and its position is secured with the self-locating seating and fastened by the screws. The adjustable cartridges are inserted to the slide blocks (110a,110b) and fastened with the grub screws. This set up is then mounted to the guideways (106a,106b) provided at the base of the tool holder (102) and positioned with the grub screws depending on the length of chamfering to be machined. The inner diameter of the header stub is measured and the suitable matching dimension of center pin is inserted into the center of the base of the tool holder (102) and secured in position with locking pin inserted across the drilled hole provided at the base of the tool holder (102).
[0042] The machining is controlled with the machine parameters to produce a smooth chamfered end and the length of the stubs is controlled with the downward feed of the tool holder.
[0043] The header stub is edge prepared without any chamfering length constraints. The header stubs thus machined eliminates inventory of different tool holders and form tools and any constraints in chamfering of header stubs with high thickness and minimum inner diameter. Likewise reducing cycle time and thereby productivity is increased.
[0044] Fig.2 shows the adjustable cartridge (112) that is provided with a back stem (122) to fit in the mounting hole in the sliding blocks of the tool holder and the head of the adjustable cartridges (112) are machined to suit the suitable carbide inserts. The adjustable cartridges (112) are fabricated by machining rod with heat treatable properties. The adjustable cartridges (112) are of two types with different positioning of insert seating. This arrangement provides overlapping of cutting length simultaneously, decreasing the cutting load to the tool and increasing its capability to take cuts for higher thickness stubs at a time. The carbide inserts seating in the adjustable cartridges is provided with a tapped hole for holding the inserts with screws.
[0045] Fig.3 shows the structure of a center pin, in accordance with an embodiment of the present invention. On the bottom of the tool holder, the base bears a center hole to suit the center pin (116). The base of the tool holder is provided with counter bored through hole across its diameter. The locking pin (120a, 120b) are inserted through this counter bored through-hole to hold the center pin in position. The center pinhead dimension remains the same for all range of inner diameter of header stubs and it is provided with through-hole suiting the dimension of locking pin. Hence the drilled hole in the center of the base of the tool holder remains common to the different sizes of the center pin and is further provided with a step up counter bore to accommodate center pins of different dimensions with adequate clearance.
[0046] The tool holder is lowered for the center pin (116) to enter the stub inner diameter until the carbide inserts are engaged with the tube, ensuring the proper positioning and alignment with the header stub during machining. The header stub to be machined is marked for the final length required after chamfering.
[0047] Fig.4 shows the structure of a locking pin (120), in accordance with an embodiment of the present invention. The locking pin (120) is inserted through this counter bored through a hole to hold the center pin in position. The inner diameter of the header stub is measured and the suitable matching dimension of center pin is inserted into the center of the base of the tool holder and secured in position with locking pin inserted across the drilled hole provided at the base of the tool holder.
[0048] Thus, with the use of a Universal edge preparation tool for semi gantry radial drilling machine as described in the present disclosure, various technical problems of the state of the art are resolved. In addition, although a number of exemplary components are described herein, those skilled in the art can appreciate that the Universal edge preparation tool can be used for machining of header stub end with outside diameter ranges between F 76.20 mm to F 31.8 mm having varying tube thickness, without deviating from the scope of the subject matter of the present disclosure.
[0049] Further, it will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope.
[0050] Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. In addition, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.
[0051] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

Claims:1. A universal edge preparation apparatus (100) for interconnecting stubs in the header of the steam generator, the universal edge preparation apparatus (100) comprising:
a tool holder (102) made of a high thickness treatable rod, wherein the dimension of the Morse taper (104) of the tool holder (102) is maintained as per the machine requirement.
a plurality of guideways (106) milled on the base of the tool holder (102), wherein the guideways (106a,106b) are identical and milled opposite to each other with respect to a centerline (108);
a plurality of slide blocks (110a,110b) accommodated inside the plurality of guideways (106a,106b), wherein the threaded holes are configured on the guideways to accommodate the respective slide blocks (110a,110b); and
a plurality of adjustable cartridges (112a,112b) configured by machining rod with heat treatable properties, wherein, the plurality of adjustable cartridges (112a, 112b) are introduced to the slide blocks (110a,110b) with the help of a grub screw.

2. The universal edge preparation apparatus (100) as claimed in claim 1, wherein the tool holder (102) is positioned on the mounting of a semi gantry radial drilling machine.

3. The universal edge preparation apparatus (100) as claimed in claim 2, wherein the base of the tool holder (102) is provided with a center hole (114) that accommodates the center pin (116).

4. The universal edge preparation apparatus (100) as claimed in claim 2, wherein the base of the tool holder (102) is provided with a plurality of counterbored through-hole provided (118a,118b) across the diameter of the base of the tool holder (102).

5. The universal edge preparation apparatus (100) as claimed in claim 4, wherein a plurality of locking pins (120a,120b) are inserted through the plurality of the counterbored through-hole (118a,118b) to hold the center pin in position.

6. The universal edge preparation apparatus (100) as claimed in claim 1, wherein the slide blocks (110a, 110b) are provided with mounting holes to accommodate the stem of the plurality of the adjustable cartridges.

7. The universal edge preparation apparatus (100) as claimed in claim 6, wherein the slide blocks (110a,110b) are provided with a tapped hole to hold the adjustable cartridges (112a,112b) with a grub screw.

8. The universal edge preparation apparatus (100) as claimed in claim 6, wherein the head of the adjustable cartridge (112a, 112b) of the tool holder (102) accommodates the suitable carbide inserts.

9. A methodology (200) utilized by universal edge preparation apparatus (100) for interconnecting stubs in the header of the steam generator, the method comprising:
mounting of the carbide inserts on the adjustable cartridges (112a,112b) wherein the carbide inserts are of a suitable grade that matches to the material of the header stub;
securing the position of carbide inserts on the adjustable cartridges (112a,112b) through self-locating seating fastened by the screws;
inserting the adjustable cartridges (112a,112b) to the slide blocks (110a,110b) and fastened with grub screws;
mounting the cartridges (11a,112b) along with carbide inserts on the guideways (106a,106b) provided at the base of the tool holder (102);
positioning the cartridges along with carbide inserts with grub screws on the guideways (106a,106b) of the tool holder (102), wherein the positioning depends upon the length of the chamfering to be machined; and
positioning the tool holder (102) on the mounting of the semi gantry radial drilling machine.