Description:“UNIDIRECTIONAL OUT FLOW DOUBLE FLOW VOLUTE CASING FOR DOUBLE CASING CENTRIFUGAL PUMP’

FIELD OF INVENTION:
[001] The present invention relates to disclosure of an efficient double flow volute casing for double casing centrifugal pump in general and inclined discharge nozzle of a double casing centrifugal pump in particular.
BACKGROUND OF INVENTION AND 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] Double flow discharge volute is pertinent to hydraulic machines to balance the hydraulic forces for better rotodynamics. High density fluid leaving impeller to volute casing causes significant radial force on rotor due to sudden discontinuity in impeller periphery at volute tongue, a plurality of volute entry point. This leads to rotodynamic problem meaning high vibration of Pump. In order to balance this radial thrust, diametrically opposite two volutes at 180o periodicity are placed around impeller is called double flow volute casing, a plurality of inner casing 2, 3. The Present invention focuses on double flow volute casing configuration.
[004] Now, reference may be made to the below prior arts:
[005] Prior art JPH03213699A, 1991-09-19, Volute casing, HITACHI LTD Ref. [1], As shown in Figure 1, various volute casings to reduce radial thrust and friction loss of a flow passage by arranging tongues and partition walls constituting a volute at equal intervals on the circumference, positioning the end of a partition wall up to the beginning of a succeeding tongue, and specifying the area ratio of an inside flow passage to an outside flow passage partitioned with the terminal end of a partition wall is disclosed. In the prior art, the double flow casing is basically a single piece volute casing made into two volutes by partition wall. Whereas the present invention relates to double casing, viz., outer casing 6 and inner casing 2,3, a plurality of double flow volute casing as shown Figure 3. Furthermore, the prior art being casted casing has tangential discharge nozzle whereas the present invention is for forged casing centrifugal pump with inclined discharge nozzle, a plurality of discharge nozzle neither tangential nor perpendicular to the casing. The present invention provides double flow volute casing for double casing centrifugal Pump.
[006] Prior art US 2022/0163037 A1, 2022-05-26 Ref. [1], As shown in Figure 2, a redirection piece 17 is welded at nose of discharge nozzle, which narrows the path to improve efficiency whereas in the present invention, the region is widened by fillet. The redirection piece 17 region in the prior art is after vaned diffuser, whereas in the present invention the diffuser is of double flow volute type diffuser also called as inner casing 2, 3 as shown in Figure 3. In the prior art, the discharge nozzle is being upright, whereas in the present invention the discharge nozzle is inclined.
[007] In view of the above, the present invention has been proposed.
OBJECTS OF INVENTION:
[008] An object of the present invention is to provide Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump.
[009] Another object of the present invention is to provide double flow volute casing for centrifugal pump with inclined discharge nozzle.
[0010] Yet another object of the present invention is to provide double volute casing that ends much before discharge nozzle to reduce skin friction and separation losses.
[0011] Still another object of the present invention is to provide Unidirectional Out Flow Double Flow Volute Casing to enable diametrically opposite volute casing flow to discharge nozzle in one direction only with a guiding piece.
[0012] 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
[0013] 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.
[0014] According to the invention, there is provided Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump comprising of below features:
[0015] A Plurality of efficient volute casing 2, 3 diffuser flow path after impeller 1 and unidirectional flow path between volute casing 2,3 and outer casing 6 till discharge nozzle 5;
[0016] A Plurality of Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump with inclined discharge nozzle 5;
[0017] A Plurality of Unidirectional Out Flow Double Flow Volute Casing 2,3 for Double Casing Centrifugal Pump that ends much before said discharge nozzle 5 to reduce skin friction and separation losses.
[0018] According to another aspect of the invention, below features are provided:
[0019] A Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump where discharge nozzle is inclined and the angle of inclination is 90+? from parting plane 7 and ? >= 0;

[0020] A double flow volute casing extending from parting plane 7 to 90 + ? from parting plane 7, where -45o < ? < 90o;
[0021] The double flow volute casing 2, 3 is extended from parting plane 7 to 90 + ? whereas discharge nozzle inclination is 90 + ?, ?>=?;
[0022] A guiding piece 4 at downstream of inner casing 3, which is opposite to discharge nozzle, a plurality of lower half of inner casing 3, a plurality of distant volute compared to discharge nozzle 5;
[0023] A good enough assembly clearance between guiding piece 4 and inner casing 3 also enables unidirectional flow a large;
[0024] The guiding piece 4 is not in main flow but a profiled wall enabling unidirectional flow only in the direction of inner casing inclination to discharge nozzle;
[0025] The double flow volute is allowed to end at angle ?, ?>0 where ?=0 signifies radial outlet to reduce vortex losses by overturning the flow.
[0026] 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.

[0027] 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.

[0028] 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 ACCOMPNAYING 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 processes that are consistent with the subject matter as claimed herein, wherein:-
[0030] Figure 1 shows: Double flow volute casings of the Prior art.
[0031] Figure 2 shows: A redirecting piece to improve efficiency according to the Prior art.
[0032] Figure 3 shows: Unidirectional Out Flow Double flow volute casing for Centrifugal Pumps Applications in accordance with the Present invention.
[0033] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPNAYING DRAWINGS:
[0034] 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.
[0035] The present invention makes a disclosure regarding a technology pertaining to an invention directing to Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump.
[0036] Thus according to the present invention, there is disclosure of efficient flow path for fluid leaving impeller, a plurality of double flow volute casing of a single discharge nozzle of centrifugal Pump.
[0037] Still more particularly the disclosure provides double volute casing for discharge nozzle inclined to plane normal to parting plane of two volutes, namely upper half 2 and lower half 3 of double casing centrifugal Pump as shown in Figure 3. Double casing means the centrifugal pump has two casing around impeller 1, wherein one is outer casing 6 and the other is inner casing 2, 3, a plurality of double flow volute casing.
[0038] Now, reference may be made to Figure 3 indicating the present invention.
[0039] The impeller 1 which is rotating element is surrounded by inner casing assembly 2, 3. The inner casing assembly is provided in two halves viz., upper inner casing 2 and lower inner casing 3. The inner casing 2, 3 is a diffusing element. The inner casing 2, 3 is also called double flow volute casing. Assembly of the impeller 1, and volute casing 2, 3 is placed in outer casing 6.
[0040] The exit flow of impeller 1 passes through double flow volute casing upper half 2 and lower half 3. The inner casing 2 and 3 are at 180o periodicity which helps in balancing radial thrust load on the impeller 1. The flow carried in the inner casing 2, 3 passes through annular space between the inner casing 2, 3 and outer casing 6 and subsequently passes through discharge nozzle 5.
[0041] The upper half inner casing 2 out flow is directed in the discharge nozzle 5 while lower half inner casing 3 out flow passes through annular space between said inner casing 2, 3 and outer casing 6 and subsequently reaches to the discharge nozzle 5. The flow lines from the upper half 2 and lower half 3 of double flow volute casing are indicated by spline 8, 9 respectively. A guiding piece 4 is placed right after exit of said lower half of the inner casing 3. The primary function of said guiding piece 4 is to allow the lower half volute casing 3 out flow largely in direction of inclination of volute casing which is along the direction of rotation of the impeller 1. The unidirectional flow is roughly indicated by thick splines 8 and spline 9 respectively.
[0042] The geometrical parameters for upper half of volute casing 2 and volute casing 3 are exactly same with 180o offset. The angular position is indicated with reference to the parting plane 7 formed which is an interface to upper volute casing 2 and lower volute casing 3 and its normal plane. Tongue start angle a is as per conventional design practice. Volute casing flow passage extends from tongue to 90 + ? included angle whereas nozzle is at 90 + ? angle from parting plane where ? >> ?. Unlike conventional volute exit, the present invention volute exit is set based on discharge nozzle position 90 + ? to direct the out flow in discharge nozzle as indicated by flow path line 9. Whereas in conventional method, ? ? ? which extends volute longer leading to higher skin friction loss and the out flow passage is radially outward towards discharge nozzle which leads to separation and vortex losses at out flow region. Thus, the present double flow volute casing 2, 3 is energy efficient.
[0043] The guiding piece 4 profile is set in line with the lower half inner casing 3 exit profile at the interface and smoothly merges to the outer casing 6 inner profile. The guiding piece 4 is welded to the outer casing 6. Sufficient assembly clearance can be given between said guiding piece and lower half of inner casing 3. The guiding piece is placed in such a way that it acts as a profiled wall to guide the flow in one direction only, i.e., counter clock wise only as shown in Figure 3, a plurality of flow in one direction only from volute out flow exit inclined direction to discharge nozzle.
[0044] Conventional practice is the volute casing outlet is radially outward whereas in the present invention, as shown in Figure 3, volute casing 2, 3 outlet geometry is not radial. The angle ? between flow line 8 and discharge nozzle 5 indicates inclination of the volute outlet. ?=0 indicates radial outlet of volute casing.
[0045] Another aspect is the fluid left over by said impeller 1 is largely tangential. To make the flow from tangential to radial, the volute casing has to be extended longer. Longer flow path leads to skin friction losses. And if the volute extension is not enough longer, it leads to flow separation and vortex losses.
ADVNATAGES OF THE INVENTION

[0046] Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump is energy efficient double flow volute casing design of centrifugal Pump. The design parameters described helps in designing volute casing with lower skin friction and separation losses.
[0047] The efficiency improvement is more than 1%. The invention provides a novel unidirectional out flow double flow volute casing for double casing centrifugal pump.
[0048] The disclosure provides double flow volute casing for centrifugal pump with inclined discharge nozzle.
[0049] Conventionally, the opposite volute outlet is arranged as flow guiding piece in the flow that deflects flow in both directions. Any obstructive object leads to more losses. Whereas in the present invention, flow guiding piece 4 is placed at one end and guides flow in direction of impeller rotation. This helps in less disturbance in the out flow from lower half 3 volute casing that helps to lower flow losses.

WORKING OF THE INVENTION

[0050] The disclosure is primarily used for low head high flow Boiler Feed Pumps requirement in secondary cycle of Nuclear Power Plant. The disclosure is applicable to any barred type of double casing pumps.

TEST RESULT

Conventional Present Invention

[0051] CFD flow analysis results for Conventional and Present inventions are compared. In the conventional type, guiding piece 4 of Figure 3 is in main flow path while in present invention the guiding piece 4 is at one side and is meant to just smoothly guide and act as a wall for unidirectional flow, a plurality of flow in impeller rotation direction only. Also outlet of one of volute close to discharge nozzle ends much before discharge nozzle.
[0052] 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.

[0053] 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.

[0054] 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”.

[0055] 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.
[0056] 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.

[0057] 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.

[0058] 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.
, Claims:We Claim

1.Unidirectional Out Flow Double Flow Volute Casing for Double Casing Centrifugal Pump comprising of:
an impeller [1] constituting a rotating element surrounded by inner casing assembly [2, 3], wherein the inner casing assembly is provided in two halves i.e. upper inner casing [2] and lower inner casing [3], in which Assembly of impeller [1] and volute casing [2, 3] is placed in outer casing [6];
the exit flow of impeller [1] passes through double flow volute casing upper half [2] and lower half [3], and the inner casing [2 and 3] are at 180o periodicity which balances radial thrust load on the impeller [2], in which the flow carried in the inner casing [2, 3] passes through annular space between the inner casing [2, 3] and outer casing [6] and subsequently passes through discharge nozzle [5].

2. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claim 1, wherein the inner casing [2, 3] is a diffusing element forming double flow volute casing.

3. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claim 1-2, wherein the upper half inner casing [2] out flow is directed in discharge nozzle [5] while lower half inner casing [3] out flow passes through annular space between inner casing [2, 3] and outer casing [6] and subsequently reaches to the discharge nozzle [5].

4. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claims 1-3, wherein the flow lines from the upper half [2] and lower half [3] of double flow volute casing are formed by spline [8, 9] respectively.

5. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claims 1-4, wherein a guiding piece [4] is placed after exit of the lower half of the inner casing [3], in which the guiding piece [4] profile is set in line with the lower half inner casing [3] exit profile at the interface and merges to the outer casing [6] inner profile.

6. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claims 1-5, wherein the geometrical parameters for upper half of the volute casing [2] and lower half volute casing [3] are exactly same with 180o offset, in which the angular position is indicated with reference to the parting plane [7] formed which is an interface to the upper volute casing [2] and lower volute casing [3] and its normal plane.
7. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claims 1-6, wherein the Volute casing flow passage extends from tongue to 90 + ? included angle and nozzle is at 90 + ? angle from the parting plane where ? >> ?.
8. The Unidirectional Out Flow Double Flow Volute Casing as claimed in claims 1-7, wherein the guiding piece [4] is fixed to the outer casing [6], in which the guiding piece [4] is placed such that it acts as a profiled wall to guide the flow in one direction, i.e. counter clock wise, in which a plurality of flow in one direction from volute out flow exit is in inclined direction to the discharge nozzle.