Description: A METHOD FOR MANUFACTURING A CAST FABRICATED IMPELLER RUNNER WITH SPLIT BLADES

FIELD OF THE INVENTION
[0001] The present subject matter described herein relates to fluid pumping impellers. More specifically, the present invention relates to a method for manufacturing cast fabricated impeller runner with split impeller blades.

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] Shifting power generation source from fossil fuels to renewable energy not only cuts emissions, it also contributes to the sustainable economic growth. Focus is also on the renewable energy addition in which hydro power has to play a major role. In coal based thermal power industry also, there is a discernible shift from sub critical to supercritical steam parameter technology.
[0004] Moreover, fast changing climatic condition and geological status resulted in acute shortage of drinking water in some parts of the country while there is excess water in other parts. In order to fulfil the requirements of farmers, urban population and industrial growth, it is inevitable to transport water from surplus zone to scarcity zone. This has triggered the concept of lift irrigation system and led to the emergence of bigger lift irrigation project (LIS) with the objective that the water to be transported as well as lifted to higher level so as to facilitate water for irrigation, drinking and Industrial purpose.
[0005] For example, Kaleshwaram Lift Irrigation Project (KLIP) in India targets pumping about 180 TMC (Thousand Million Cubic feet) from Godavari River at the rate of 2 TMC per day from Medigadda and 20 TMC from Yellampally. The height of final pumping is +624 RL (River Level), which is almost 525 meters higher than the intake wells at Medigadda (+100RL).
[0006] The project involves multistage pumping, tunnels, canals, reservoirs and complex web of water transport systems. This is the massive lift irrigation scheme and first of its kind in the country for its height, quantity, stages of pumping, storage systems and the complexity involving in synchronizing all the components. Such projects require impellers for water lifting purpose, the component weight of each impeller can reach upto 40 MT depending on the capacity of electrical motor which can reach upto 150 MW.
[0007] Such bigger LIS projects necessitate multistage pumping stations with well-equipped electromechanical devices having electrical pumps with capacity up to 150 MW. Thus the impeller required to drive huge electrical motors for lifting water to an even higher elevations are also bigger.
[0008] Impeller casings often constitutes considerable material of these impellers and therefore significantly contributes to the cost of the impeller, and the hydro plant thereof. If these impeller casings are made of integral material of single casting, the cost of the impeller module is even higher.
[0009] The manufacture of such heavy and bigger size impeller casings also demand the provisions of correspondingly large manufacturing facilities, with the associated lifting, manipulation, moulding and pouring means. This limits the supplier competition which thereby push the cost further up. Also it leads to lower productivity due to profile complexity, which directly impacts the efficiency and cost viability.
[0010] The most critical part of the impeller is the blade which throws a major challenge in manufacturing, as it has complex changing profile that is prone for distortions during various stages of manufacturing. In order to maintain exact profile dimensions, it is imperative to design and develop an accurate and robust fixture which has to not only hold both the parts at right position, but ensure distortion free stability all throughout the fabrication process.
[0011] However, manufacturing complicated & bigger size castings with material grade is a challenge as the metallurgy of the components involved is exotic.
[0012] Thus, there exists a need to save significant manufacturing time involving lesser resources and with accuracy but also with involvement of executing apparatus means that makes this achievable low initial cost and upkeep, great and continuing accuracy inherent in its design and operation, ruggedness and simplicity in its construction and operation, all to the ultimate end of faithfully and consistently reproducing in and through the desired quality of operation.
[0013] Also, to manufacture the impeller blades in the existing structure, stainless steel is required. In order to prepare stainless steel with low carbon content, it is essential to have an EAF (Electric arc furnace) as well as a VOD (Vacuum Oxygen Decarburization). The EAF involves a refractory-lined hearth, a shell and a roof to contain the molten metal. Scrap metal is first loaded into the furnace; long, cylindrical graphite electrodes are then lowered into the charge of scrap through the roof. Afterwards, high current is delivered into the charge through the electrodes, for melting the scrap. Alloying elements are added to achieve on-grade chemistry.
[0014] The VOD, is a process well-suited to the production of stainless-steel alloys. In the VOD, through the decarburization process the amount of carbon in the melt is refined. Oxygen and inert gas (such as nitrogen or argon) are blown into the stainless steel in precise ratios. Afterwards, desulfurization is done to achieve high toughness values for longer service life.
[0015] The liquid metal requirement for such bigger casting is approx. 80-100 MT which varies based on the design. Usually, it is difficult to manufacture such big integral casting with existing setups.
[0016] To overcome this challenge of handling and melting of such large amount of liquid metal, a cast fabrication route is envisaged. However, the new solution raised further challenges such as dimensional control of impeller blades which are in aerodynamic profile shape and having length up to 5000 mm and highly prone for distortion during various stages of manufacturing because of the slenderness in shape that may lead to complete rejection or huge rework. Limited source of machining facilities, i.e. machineries having correspondingly large bed length upto 5000 mm with provisions of multi axis with CNC controls are used.
[0017] It is an aim of embodiments of the present invention improve the problems as mentioned in the prior art.

OBJECTS OF THE DISCLOSURE
[0018] It is therefore the object of the present disclosure to overcome the aforementioned and other drawbacks in prior arts.
[0019] It is a primary object of the present disclosure to provide a method of manufacturing an impeller with split impeller blades and subsequent integration with other components to meet the design and operational requirement.
[0020] It is another object of the present disclosure to save significant manufacturing time involving lesser resources and with accuracy
[0021] It is another object of the present disclosure to provide a method of manufacturing an impeller with split impeller blades that is simple in its construction and operation.
[0022] It is another object of the present disclosure to mainrain quality of manufacturing the blades.
[0023] 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
[0024] 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.
[0025] 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.
[0026] The present disclosure offers a solution in the form of a method for manufacturing a cast fabricated impeller runner with split blades. The method comprising steps of splitting impeller blades into two parts for machining, thereby forming split blades, joining the split blades in form of a full profile single blades on the cast fabricated impeller runner, the joining comprises of producing a layout to minimize a number of points on the layout, maintaining dimensional accuracy and stiffness of the cast fabricated impeller runner by a plurality of templates and assembling the full profile single blade of the split blades on the cast fabricated impeller runner.
[0027] In an aspect of the invention, multiple profile check templates and blade setting templates are made using a CNC profile cutting machine.
[0028] In a further aspect of the invention, a support fixture and a welding procedure is established to restrict unwanted movement during welding and cooling of the weldment.
[0029] In an aspect of the invention, the lifting tackles are designed for both the split blades taking the angle and orientation of the split blades into consideration to retain the position and shape of the split blades during lifting and setting on the support fixture.
[0030] In an aspect of the invention, a root gap is maintained at the welded joint portion as per design requirement.
[0031] In an aspect of the invention, movement of the split blades on the cast fabricated impeller runner is maintained using axial screw jacks placed besides different control points.
[0032] In an aspect of the invention, the check points are introduced across all (X, Y & Z) planes by using complete profile templates and dimensional check sheet.
[0033] In an aspect of the invention, a weld edge is provided on the split blades.
[0034] In an aspect of the invention, dimensional compliance of a welded joint portion on the split blades is ensured by a plurality of check points, reviewing control points and check sheet to incorporate necessary modifications on the split blades.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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
[0039] 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:-
[0040] 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:
[0041] Fig. 1(a) illustrates integral casting and individual components (a) cast integral impeller Runner (b) Skirt Component (c) Crown Component (d) impeller blade components, in accordance to the present invention;
[0042] Fig. 1(b) illustrates (a) full profile impeller blade suction side (b) full profile impeller blade pressure side representing the split plan of the blade into two parts, in accordance to the present invention;
[0043] Fig. 2(a) and 2(b) illustrates split blades, in accordance to the present invention;
[0044] Fig. 2(c) illustrates full profile single blade, in accordance to the present invention;
[0045] Fig. 2(d) illustrates developing weld edge on the split blades, in accordance to the present invention;
[0046] Fig. 3(a) illustrates a development of a layout, in accordance to the present invention;
[0047] Fig. 3(b) illustrates a template designed for profile checking and support to control distortion, in accordance to the present invention;
[0048] Fig. 4 illustrates a typical dimension control check points of Runner Assembly (a) Blade inlet & discharge diameter (b) Blade Outlet Pitch (c) Impeller Outlet height (d) Blade Inlet opening (e) Blade outlet angle & (f) Blade profile, in accordance to the present invention;
[0049] Fig. 5 illustrates typical zones for welding & NDT requirement as per material specification. Zone L1 & L5 are full weld penetration zones;
[0050] Fig. 6 illustrates a method for manufacturing cast fabricated impeller runner with split impeller blades in accordance with the present invention;
[0051] Figure 7 shows the assembled split impeller blades on the cast fabricated impeller runner.
[0052] 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.
[0053] 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:
[0054] 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.
[0055] 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.
[0056] The present invention is related to manufacturing fabricated impeller runner with split impeller blades. The present invention aims at disintegrating the large casting into smaller components followed by joining them through cast fabrication process.
[0057] A typical weight range and liquid metal requirement of individual components vis-a-vis integral casting is tabulated below:
Component Detailed Description of individual components No of component castings required for 1 Runner (No’s) Cast component Weight Liquid Metal Requirement
Impeller Runner (Integral) Impeller Runner (Integral) 1 42 98
Cast Fabricated (Impeller) Crown (Component) 1 24 56
Skirt (Component) 1 8 20
Blades (Component) 6 (depends on design) 10 22

[0058] Referring to Fig. 1a, the (a) cast fabricated impeller runner (101) and the components of the cast fabricated impeller runner (101) such as (b) a skirt (102), (c) a crown (103) and (d) the blades (104) are shown.
[0059] Referring to Fig. 1(b), (a) full profile impeller blade suction side and (b) full profile impeller blade pressure side representing the split plan of the blade into two parts is shown.
[0060] Referring to Fig. 2(a)-2(b) and Fig. 6, a method (600) for manufacturing the cast fabricated impeller runner (101) with the split blades (201, 202) is provided. The first step (601) includes splitting the impeller blades (104) into two parts forming the split blades (201, 202) thereby resulting in substantial reduction in manufacturing cycle time as well as machining. It enables to manufacture blades for more than 18 cast fabricated impeller runner(s) (101) in a year.
[0061] The impeller blades (104) are large in length with continuously changing profile having less thickness to length ratio which is prone for distortion during operation, the critical point for selection of location of splitting and the point of splitting the impeller blades (104) is that the split blades (201, 202) are:
• Suitable for welding.
• Suitable for fixture development for fabrication of the split blades (201, 202).
• Suitable for use optimum machining facility.
• Operational requirement of the cast fabricated impeller runner.
[0062] Referring to Fig. 2(d), a weld edge is provided on the split blades (201, 202) considering minimum weld deposition that minimizes the extent of distortion.
[0063] The components of the impeller blades (104) components are required with surface finish of approx. 03 micron and aerodynamic changing profile which is extremely difficult to manufacture through manual grinding for achieving dimensional control using templets. Therefore, to increase productivity and enhance overall equipment efficiency, upgradation of impeller blades has been explored with 5 axis CNC machine. This triggered the requirement of splitting the impeller blades (104) into two part thereby forming the split blades (201, 202) .
[0064] Referring to Fig. 2(c). In the second step (602), the split blades (201, 202) are joined with negligible distortion to form a full profile single blade (203), hence proper dimension is mandatory to comply with the design requirement. The split blades (201, 202) need to assemble first for the full profile single blade (203) and further in the cast fabricated impeller runner (101) for complete assembly.
[0065] The split blades (201, 202) are large in length with continuously changing profile and have less thickness to length ratio which is prone for distortion during fabrication of assembly. Therefore the below process is used to join the split blades (201) with negligible distortion.
[0066] Firstly, a 2D layout (301) is made by using 3D model (Ref. to Fig. 3a). During the layout (301) drawing development, emphasis is given to minimize the number of points on the layout (301) to facilitate ease of handling and setting of the split blades (201, 202) on a fixture using EOT cranes, that are required to control the complete profile dimensions.
[0067] Subsequent to development of the layout, it is essential to develop templates (302) (Ref. to Fig. 3b) to fulfil dual purpose, i.e. to maintain dimensional accuracy and also provide stiffness to the impeller runner. Further, the templates (302) include multiple profile check templates and blade setting templates that are made using CNC profile cutting machine.
[0068] To ensure the assembly of split blades numbers of the templates (302) developed for checking to ensure dimensional compliance. List of main templates (302) are as under:
A. Full profile template for Section EE
B. Full Profile template for Sec-FF
C. Sectional Template for 300 mm P1 pressure side
D. Sectional Template for 400 mm P1 Pressure side
E. Sectional Template for 300 mm P2 pressure side
F. Sectional Template for 400 mm P2 Pressure side
G. Sectional Template for 600 mm P1 Suction side
H. Sectional Template for 600 mm P2 Suction side
[0069] Further, lifting tackles are used for lifting and setting the split blades (201, 202) on the cast fabricated impeller runner (101) by taking the angle and orientation of split blades (201, 202) into consideration and also retain the shape of the split blades (201). The split blades (201, 202) are fixed on the cast fabricated impeller runner (101) by maintaining the root gap at a joint as per design requirement. The movement of the split blades (201, 202) on the cast fabricated impeller runner (101) is controlled through development of axial screw jacks placed besides different control points.
[0070] To ensure dimensional compliance of welded joint portion of full profile single blade (203) formed of the split blades (201, 202) and also to avoid any rework/ rejection, several check points are introduced across all (X, Y & Z) planes by using the profile templates and dimensional check sheet, apart from having instructions for do’s and don’ts.
[0071] Further, controlling and minimizing the distortion is developed by excessive heat input during welding for joining of the split blades (201, 202). To minimize the distortion, a support fixture is developed and the welding procedure is established to restrict the unwanted movement during welding and cooling of the weldment. The support fixtures are developed where movement of assembly is restricted through 14 points in the form of tag welding or screw jack or wedge fitment control. Also welding sequence is planned in such a way that minimum heat input is generated in a particular zone. Moreover, the heat input developed in one sequence is minimized/ neutralized by the next sequence.
[0072] Further, review of control points and check sheet is done after completion of the welding to incorporate necessary modifications in the system to fine-tune the process for better accuracy.
[0073] After development of procedure for the split blade (104) fabrication to full profile single blade (203), the next step is to assemble (as provided in the third step 603) all the 6 full profile single blades (203) while maintaining dimensional accuracy and adhering to stringent critical control parameters for welding to avoid any distortion by using multiple fixtures. The fixtures that are developed require setting points for fabrication. The critical points that are taken care for achieving the desired result are as under:
• Layout marking on bottom part (crown) for all the full profile single blades (203) to maintain Pitch Circle Diameter (PCD)
• Placement of all the full profile single blades (203) on crown
• Checking and setting of inlet and outlet PCD
• Checking and setting of height at inlet and outlet water path
• Placement of skirt (top part)
• Fixing of complete assembly using wedges and tag welding
• Complete dimensional verification of the runner assembly (some typical dimension control pints provided as shown in Figure 4
• Strengthening complete assembly using stiffeners and wedges to restrict any distortion and unwanted movement
• Sequential welding in partial and full penetration zone
• DP (Die Penetration test)/MP (Magnetic particle test) for back surface preparation of developed weldment in full penetration zone
• Completion of welding of balance zone
• Stress relieving of complete cast fabricated impeller runner assembly
• Final NDT (Non-destructive testing) and dimensional verification
[0074] In the initial phase the cast fabricated impeller runner (101) was divided into major components, i.e. the crown (102), the skirt (103) and the blades (104) to form the main component. Also, the blades are split into two forming the split blades (201, 202). After manufacturing these individual components through casting route, they were weld fabricated to achieve the cast fabricated impeller runner (101).
[0075] The material(s) given given above is as an example without restricting scope of the invention to the same. Thus, other materials readily apparent to a person skilled in the art are undertood to be within scope of the invention.
[0076] Referring to Fig. 5, The complete weld edge is divided in 3 part outlet, inlet and centre part. In both end i.e. outlet and inlet full penetration welding is carried out to achieve higher toughness and subject zone is prone to cracking during operation. The centre part is partial penetration welding, partial penetration helps to assemble blade easily and less amount of weld deposit.
[0077] Further, both end require stringent non-destructive testing for surface and volumetric discontinuity whereas central part only subjected to surface testing requirement.
[0078] From the above, working of invention can be understood particularly by a person skilled in the art.
[0079] After successful completion of joining the two split blades (201, 202) into single profile blade, the fabrication of impeller runner was done as per the procedure established to fabricate the Impeller runner. Welding of assembly is also critical from the perspective of dimensional control and also in view of the cracking tendency of the weldment as the quantity of weldment is quite huge to the tune of 96-120 running meter and weld deposition of 900-1000 Kgs. The Average weld thickness to be developed ranges from 60-90 mm depending on location and criticality during operation. Leading and trailing edge of runner requires full penetration welding and subjected to stringent ultrasonic and die penetration and magnetic particle test requirement, whereas balance zone is partial welded. Figure. 6 demonstrates the zone mentioned for requirement of partial weld development, full penetration weld and Non-Destructive testing requirement.
[0080] Ref. to Fig 1-7, it shows the actual job during implementation is presented in Fig. 7 that includes all components viz. the skirt (102), the crown (103) and the blades (201, 202). Also fabrication of the split blades (201, 202) along with the templates (302) and the fixture are shown representing assembly process of the cast fabricated impeller runner (101).
TECHNICAL ADVANTAGES
[0081] With the help of the solution as proposed herein in the context of the present disclosure, dimensional accuracy could be achieved with close tolerance of 8 mm in first attempt itself for a length of 4200 mm i.e. distortion could be controlled well below 0.25%. Further review of the parameters w.r.t. fixture design and pattern modification could yield dimensional accuracy within 0.1 % tolerance.
[0082] The higher liquid metal melting and handling capacity as would have been required in case of integral runner, has been reduced by 40% by disintegrating the large casting into smaller components.
[0083] With the help of the present invention, two spilt blades are welded well within 36 hours including fixing time. Each blade fabrication required approx. 24 Kgs of weld deposit with welding electrode SFA 5.4 E410 NiMo-15 of ASME BPVC.II.C.
[0084] Complete profile machining was envisaged which enabled to achieve perfect surface finish and dimensional control compared to integral runner casting where it would have been manufactured through manual material removal or grinding process
[0085] The welding was planned in such a way that the distortion developed by one step will neutralize or counter the distortion due to the subsequent welding sequence there by retaining the original profile dimension
[0086] 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.”
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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”.
[0091] 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.
[0092] 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.
[0093] 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.
[0094] 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.
, C , Claims:WE CLAIM
1. A method (100) for manufacturing a cast fabricated impeller runner (101) with split blades (201, 202) , the method comprising steps of:
splitting (101) impeller blades (104) into two parts for machining, thereby forming split blades (201, 202) ;
joining the split blades (201, 202) in the form of a full profile single blade(s) (203) on the cast fabricated impeller runner (101), the joining comprises steps of:
producing a layout (301) to minimize a number of points on the layout;
maintaining dimensional accuracy and stiffness of the cast fabricated impeller runner (101) by a plurality of templates (302); and
assembling (103) the full profile single blade (203) of the split blades (201, 202) on the cast fabricated impeller runner (101) using lifting tackles.
2. The method as claimed in claim 1, wherein the plurality of templates (302) include multiple profile check templates and blade setting templates made using a CNC profile cutting machine.
3. The method as claimed in claim 1, wherein a support fixture and a welding procedure is established to restrict unwanted movement during welding and cooling of the weldment.
4. The method as claimed in claim 1-3, wherein the lifting tackles are designed for both the split blades (201, 202) taking the angle and orientation of the split blades (201, 202) into consideration to retain the position and shape of the split blades (201, 202) during lifting and setting on the support fixture.
5. The method as claimed in claim 1, wherein a root gap is maintained at the welded joint portion as per design requirement.
6. The method as claimed in claim 1, wherein movement of the split blades (201, 202) on the cast fabricated impeller runner (101) is maintained using axial screw jacks placed besides different control points.
7. The method as claimed in claim 1, wherein the check points are introduced across all (X, Y & Z) planes by complete profile templates and dimensional check sheet.
8. The method as claimed in claim 1, wherein a weld edge is provided on the split blades (201, 202).
9. The method as claimed in claim 1, wherein dimensional compliance of a welded joint portion on the split blades (201, 202) is ensured by a plurality of check points, reviewing control points and check sheet to incorporate necessary modifications on the split blades (201, 202).