MXPA06011009A - Improved velocity profile impeller vane - Google Patents

Abstract

In accordance with the present invention, an impeller for use in a centrifugal pump has at least one vane the radially outer terminal end of which is configured to produce a flow velocity profile that controls and reduces the wear caused by slurry fluid being expelled from the impeller on the inner surface of the pump casing. The impeller vanes of the present invention are generally configured with a radially outwardly extending portion, as compared with the conventional straight or concave edge of an impeller vane. The outwardly extending portion may vary in shape, but is selected to produce a flow velocity profile that reduces wear in the pump casing.

Description

IMPELLER PALETTE WITH IMPROVED SPEED PROFILE BACKGROUND OF THE INVENTION Field of the Invention: This invention relates to pump impellers and specifically relates to an impeller having specially configured vanes or vanes to selectively determine the speed profile of the impeller for thereby selectively modify the wear of the pump casing when processing suspensions. Description of Related Art: Rotodynamic pumps are used in a variety of industries to process liquids and suspensions. The type of fluid that is processed stipulates the type and configuration of the pump that is used in the particular application. That is, pumping clear liquids puts less demand on the pumps than does the processing of suspensions, which contain a quantity of solids or particulate matter that is abrasive and degrades the internal structures of the pump. Therefore, pump designers and engineers should consider the type of fluid or suspension that will be processed and select or design a propeller and pump housing that is most suitable for the application. For example, in the processing of clear liquids (eg, water), it is typical for the pump casing to be a volute, the shape of which changes in its cross-sectional area from the tajamar of the pump to close to the discharge of the pump. the pump, and comparatively little wear is observed in the pump casing. In the processing of suspensions, however, pump designers must consider the effect of the geometry of the hydraulic surface not only from the point of view of optimizing the efficiency of the pump, but also from the point of view of minimizing wear. in the pump housing. Therefore, it has been typical in the design of suspension pumps to modify the overall volute shape of the liquid processing pumps to provide, for example, impeller outputs and wider housings with parallel sides. Another factor that determines the wear of the casing is the shape of the impeller blades. Specifically, it has been shown that the outer edge of the impeller vanes significantly affects the speed of fluid flow that moves through the pump. It has been observed that the typical configuration of the vanes having a straight outer edge, at or near the periphery of the casing, produces a certain fluid velocity that leads to wear of the pump casing along both sides of the casing. the scroll Therefore, it would be advantageous in the art to provide impellers having vanes that are specifically designed or configured to produce a more uniform wear pattern, thereby extending the overall life of the pump casing when processing suspensions, in particularly those with high solids content and / or a particularly abrasive solids content. BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, there is provided an impeller having at least one blade that is shaped particularly at the outer terminal end thereof to produce speeds that are less detrimental to wear on the pump casing when suspensions are processed. The vane configurations of the present invention can be adapted for use in any rotary-dynamic pump, which employs an impeller, but is described and illustrated herein in connection with use in a centrifugal suspension pump. The impeller of the present invention comprises at least one vane which extends from or near the midpoint of the impeller, corresponding to the central axis of the pump that extends out radially, towards the peripheral edge of the impeller, where the vane has a external terminal end defined. The impeller of the present invention may have a reinforcing ring (generally known as a semi-open impeller), two reinforcing rings (generally known as a closed impeller, or may not have reinforcement rings generally known as an open impeller). The invention is described here, however, by having at least one reinforcing ring, which is positioned for its orientation towards the propulsion side of the pump casing (ie, the opposite of the pump inlet). The outer terminal end of the vanes of the present invention is configured with a radially outwardly extending portion, which generally defines a cambered edge of the vane. As used herein, the term "warped" is not considered to be limited to the conventional definition of a curved surface, but is made to disclose that the outer terminal edge of the pallet extends radially outwardly relative to the axis. central of the impeller, instead of being straight or curved inwardly, radially, towards the central axis of the impeller, the outer terminal edge may have any shape, including but not limited to hemispherical, curvilinear, or composed of two or more criss-crossed lines. The cambered outer end of the vanes of the present invention generally produces a fluid velocity profile that reduces wear on the inner surface of the pump housing. The shape of the curved outer end of the vanes can be selected in particular to modify or specifically determine the velocity profile of the fluid such that, given a particular type of suspension to be processed, the wear of the pump casing is You can control and reduce. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS In the drawings, which illustrate what is believed to be the best way to carry out the invention: FIG. 1 is a descriptive elevation view of a centrifugal pump illustrating a conventional scroll pump housing; FIG. 2 is a descriptive cross-sectional view of the pump illustrated in FIG. 1, taken on line 2-2; FIG. 3 is a partial cross-sectional view of a conventional impeller blade, illustrating the terminal end of the blade, which has a straight edge; FIG. 4 is a partial cross-sectional view of another conventional impeller vane, illustrating the terminal end of the vane, which is concave; FIG. 5 is a schematic representation of the fluid velocity profile of a vane having a terminal end as shown in FIG. 3; FIG. 6 is a schematic representation of the fluid velocity profile of a vane having a terminal end as shown in FIG. 4; FIG. 7 is a schematic representation of the fluid velocity profile of a vane configuration of the present invention, the terminal end of which comprises an outwardly extending edge; FIG. 8 is a descriptive cross-sectional view of a first embodiment of the present invention; FIG. 9 is a descriptive cross-sectional view of a second embodiment of the present invention; FIG. 10 is a descriptive cross-sectional view of a third embodiment of the present invention; FIG. 11 is a descriptive cross-sectional view of a fourth embodiment of the present invention; FIG. 12 is a descriptive cross-sectional view of a fifth and sixth embodiments of the present invention; FIG. 13 is a descriptive cross-sectional view of a sixth embodiment of the present invention; and FIG. 14 is a descriptive cross-sectional view of a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 descriptively illustrates a centrifugal pump 10 comprising an impeller 12 and a housing 14 of the pump. An intake 16 is provided through the housing 14 of the pump, which delivers the incoming fluid to the impeller 12. The housing 14 of the pump shown in FIG. 1 is a casing of the volute type which extends from a cut-off 18 to a discharge 20. As indicated by the arrows placed inside the casing 14 of the pump in FIG. 1, and as further illustrated in the cross-sectional view of FIG. 2, it can be seen that the cross-sectional area of the pump volute typically increases from the tapping 18 of the pump 10 to the discharge 20 of the pump 10. As shown in FIG. 2, when the impeller 12 is rotated by the drive arrow 22, the fluid entering the intake 16 moves towards the impeller 12 and is expelled outwardly into the volute 24 of the pump casing 14. The ejected fluid further moves along the volute 24 of the pump casing 14 from the tapping bore 18 to the discharge 20 and encounters a progressively larger cross-sectional area of the pump housing 14, as depicted in FIG. FIG. 2. As further shown in a descriptive manner in FIG. 1, the impeller 12 of a conventional pump has at least one blade 30, and usually a plurality of blades 30, which protrude radially outward from a point at or close to the center 32 of the impeller 12. As shown more clearly in FIG. 3, for example, the impeller 12 may have a reinforcing ring 34, which is generally formed as a flattened disk having a central point 32 corresponding to the central axis of the pump. The vanes 30 extend outwardly from or near the center 32 of the reinforcing ring 34 towards the peripheral edge 36 of the reinforcing ring 34 where the vanes terminate. Each vane 30 has a front face 38 against which the incoming fluid collides when the fluid is expelled outward, radially, towards the volute 24 of the pump casing 14 (FIG 2). Again with reference to FIG. 3, the outer terminal end 40 of each vane 39 defines an edge 42, as shown in the cross-sectional view taken on the Y line through the vane 30. FIG. 3 represents a first conventional configuration for a pallet 30, which has a straight edge at the outer terminal end 40 of the pallet 30. The straight outer edge 42 of this conventional pallet type 30 is generally co-terminal with the edge 36 peripheral of the reinforcement ring 34, as shown. FIG. 4 illustrates another conventional configuration of an impeller blade 30 where the outer edge 44 of the outer terminal end 40 of the blade 30 is concave, as illustrated in the cross-sectional view taken on line X through the blade 30. That is, the outer edge 44 arcs inward towards the center point 32 of the reinforcing ring 34, and the center 46 of the edge external 44 is co-terminal with peripheral edge 36 of reinforcing ring 34. It has been shown that the shape of the terminal end of the vane affects the flow velocity of the fluid exiting the impeller, thereby affecting the type of wear pattern that can be experienced in the pump casing when processing suspensions. As shown in FIG. 5, for example, it has been shown that a conventional pallet having a straight outer edge 42 produces a flow velocity profile where the fluid is ejected at a higher velocity at or near the 48, 50, axial sides of the pallet than from the center of the pallet between the sides 48, 50 axial. As a result, a wear pattern occurs in the pump housing on either side of the volute in a spiral pattern. As shown in FIG. 6, the flow velocity profile produced by a conventional pallet having a concave outer edge 44 is similar to the flow velocity profile produced by a pallet having a straight external edge 42, except that it occurs, or a double peak occurs of flow velocity, at the axial ends of the vane. As a result, double spiral wear is observed along the volute of the pump casing when suspensions are processed through the pump. In both conventional pallet configurations shown in FIGS. 5 and 6, relatively minor wear occurs in the center of the pump volute. In view of the foregoing, it would be advantageous to provide a pallet configuration having an external terminal end that is suitably shaped to produce a flow velocity profile that results in more controlled and reduced wear on the casing volute of the casing. pump compared to conventionally known impeller blades. The inventors have discovered that a vane 60 having a cambered outer edge 62, as illustrated, for example, in FIG. 7, produces a flow velocity profile where the velocities are distributed more evenly across the volute of the pump casing, thereby resulting in a more uniform wear of the inner surface of the casing, than would normally occur with the conventional pallet configurations.

FIG. 8 illustrates more clearly that, in general, the impeller vane 60 of the present invention has an outer end 64 terminating an outer terminal edge 62 that has a cambered shape because the edge 62 includes a portion 66 that extends radially outwardly. extending beyond the peripheral edge 36 of the reinforcing ring 34, thus, the radius Rv of the outwardly extending portion 66, when measured from the center 32 of the impeller 34 to the outermost terminal 68 of the impeller 60, is greater than the radius Rs of the reinforcing ring 34. As explained more fully below, the shape of the portion 66 extending outwardly from the end 64 can vary and can be specifically selected to produce the desired flow velocity profile consistent with the pumping requirements of a given application. FIG. 8, however, illustrates a first embodiment of the invention where the outer terminal end 64 of the pallet 60 has an outwardly extending portion 66, which has a radius Rv which is greater than the radius Rs of the ring 34 of reinforcement. The outer edge 62 is also configured with a portion 70, 72 on either side of the outwardly extending portion 66, which has a radius RB which, in this embodiment, is equal to the radius Rs of the reinforcing ring 34. Therefore, the pallet 60 has a width Wv and the portion 66 has a width WP that is smaller than the width Wv of the pallet 60. It should be noted that in the equally suitable alternative embodiments described more fully below, the width WP of the outwardly extending portion 66 may be equal to the width Wv of the vane 60. In the first embodiment of the present invention shown in FIG. 8, the outwardly extending portion 66 has an arched shape in general, when measured from Point A, to terminal 68 of portion 66 that extends outward, from there to Point B. Therefore, in a manner for example only, the outwardly extending portion 66 may have a radius Rc. However, the arcuate line between Point A, terminal 68, and Point N need not have a consistent radius (ie, an arc). Those skilled in the art, consistent with the description thereof, will understand that the dimensions of the arcuate or curvilinear line forming the outwardly extending portion 66 can be suitably varied to produce a desired flow velocity profile as shown in FIG. describes In an alternative embodiment of the invention shown in FIG. 9, the outer edge 62 of the pallet 60 includes an outwardly extending portion 66 having a terminal 68 defining a radius Rv of the pallet 60. The outer edge 62 further has a portion 70, 72, on either side of the portion 66 extending outwards, the radius RB of which is smaller than the radius Rs of the reinforcement ring 34. In addition, the radius Rs of the reinforcing ring 34 is smaller than the radius Rv of the extending portion 66. The outwardly extending portion 66 is defined between the point A, the terminal 68 of the pallet 60, and the point B, and has a width WP. The width WP of the outwardly extending portion 66 is smaller than the width Wv of the pallet 60. In the alternative embodiment of FIG. 9, the outwardly extending portion 66 is illustrated, by way of example only, by being formed of two criss-cross lines, the first line being defined between Point A and terminal 68 of pallet 60, and the second line 76 which is defined between terminal 68 and point B. This embodiment further serves to illustrate that the shape of the outwardly extending portion may be different from an arched or curved line, as shown in FIG. 8, and may be composed of a plurality of intersecting lines. Again, those skilled in the art will understand from the description here that the shape of the outer edge 62 of the pallet 60 can be suitably modified in any variety of ways to provide a desired flow velocity profile. The illustrated embodiments of the impeller blade of the present invention represent a terminal 68 of the blade 60, which is centered in relation to the width Wv of the pallet 60. However, it should be noted that the terminal 68 can be located other than on the center line 80 of the pallet 60 and for the width Wv as can be stipulate or require to achieve the desired flow velocity profile.

FIGs. 8 and 9 represent alternative embodiments of the invention - where the radius R is a cross-sectional descriptive view of a fifth embodiment of the present invention, is greater than the radius of the reinforcement ring Rs and / or the radius of the base RB FIGs. 10 and 11 illustrate another alternative embodiment of the invention. FIG. 10, for example, illustrates an alternative embodiment where the paver radius Rv is slightly smaller than the radius of the reinforcing ring Rs, and both the radius of the palette Rv and the radius of the reinforcing ring Rs are greater than the base of the reinforcement ring. RB radio. Still another alternative embodiment is illustrated in FIG. 11, wherein the radius R of the paddle 60 and the radius Rs of the reinforcing ring 34 are substantially equal, and both are greater than the radius of the base RB of the paddle 60. Sequence of amino acid modalities illustrated in FIGS. 10 and 11, achieve a desired flow rate that produces less breaks on the volute of the pump casing. It should be noted that the outwardly extending cambered portion 66 shown in FIGS. 10 and 11, is represented as a semi-spherical shape by way of example only, and other warped shapes or dimensions are appropriate and / or useful.

Furthermore, as noted previously, the position of Point A and Point B, which define the opposite axial ends of the outwardly extending portion 66, can be located on either side from closer to the center line 80 (FIGS. 8 and 9) of the paddle 60 to the axial ends 82, 84 of the paddle 60, as shown in FIG. 12. Therefore, the distance D between Point A and Point B can be from D = WV to approximately D = Wv / 3, and Point A and Point B can be equally or unequally separated from the centerline. of the palette. With reference again to the embodiment of the invention shown in FIG. 12 the axial ends of the outwardly extending portion 66, defined as the point A and the point B, extend to the ends 82, 84, of the pallet 60. Ens. , the illustrated embodiment of FIG. 12, does not have the side portions (70, 71) as in the embodiments of FIGs. 8-11, but the axial ends (Point A, Point B) of the outwardly extending portion 66 can be visualized as defining the base radius RB of the vane 60. Therefore, in a fifth embodiment of the invention shown in FIG. 12, the radius Rv of the vane 60, defined from the central axis 32 of the impeller to the terminal 68 of the vane 60, is greater than the radius Rs of the reinforcing ring 34, and the radius of the base RB is equal to the radius of the reinforcement ring Rs.

In a sixth alternative embodiment also shown in FIG. 12 in dotted line, the reinforcing ring 34 can extend beyond the base radius RB of the blade 60 a selected distance such that the peripheral edge 36 'of the impeller extends to a radius R's. The radius Rv of the pallet 60 is, therefore, greater than RB and Rs'. In a seventh alternative embodiment shown in FIG. 13, the terminal 68 of the vane 60 may not extend to the peripheral edge 36 of the reinforcing ring 34. Therefore, in this embodiment, the portion 66 extending outward from the vane does not extend beyond the reinforcing ring 34, but still advantageously affects the flow velocity profile of the impeller. In the embodiment of FIG. 13, the radius Rv of the vane 60 is greater than the base radius RB but smaller than the radius Rs of the reinforcement ring 34. In still another alternative embodiment of the invention, shown in FIG. 14, the terminal 68 of the vane 60 extends to a point substantially equal to the peripheral edge 36 of the reinforcing ring 34 such that the radius Rv of the vane 60 and the radius Rs of the reinforcing ring 34 are equal, or substantially thus, and the radius of the base RB is smaller than the radius Rv of the blade or the radius Rs of the reinforcing ring. Again, although the warped edge of the embodiments illustrated in FIGS. 12-14 is arched, the portion 66 that extends outwards can have any suitable shape as previously described. Regardless of the shape of the outwardly extending portion 66 of the pallet 60, as illustrated and described previously, the area of the shape may preferably be between about 30% to about 85% of the area defined by WV (RV ~ RB) • The following table illustrates only some of the possible dimensional ranges of the variables described here, but it is not considered to be an exhaustive definition of the ranges.

The impeller vanes of the present invention are configured to provide a selected velocity and flow profile which controls and / or reduces wear on the pump casing, caused by fluid suspensions that are ejected from the impeller into the casing. The impeller blades can be adapted for use in virtually any type, size or variety of rotodynamic pumps. Those persons skilled in the art, assigned with the description herein, will understand the changes and adaptations that can be made to employ the impeller blades in various pumps, to produce the desired flow velocity profile. Therefore, the reference here to the details or the specific embodiments of the invention are by way of illustration only and not by way of limitation.

Claims (21)

1. CLAIMS 1. An impeller for a centrifugal pump, characterized in that it comprises at least one vane extending radially in length from a central axis of the impeller to an outer peripheral edge of said impeller, and having a central line which extends as far as possible. length of said radial length, which is perpendicular to said central axis of said impeller and said at least one vane having an outer terminal end at or near said peripheral edge of said impeller, said terminal end having a portion extending outward, which has a convex or warped shape. The impeller according to claim 1, characterized in that it further comprises at least one reinforcing ring, having a peripheral edge having a peripheral edge defining said peripheral edge of said impeller, said at least one pallet extending towards outside from said reinforcement ring. The impeller according to claim 2, characterized in that said outwardly extending portion has a terminal and a radius Rv measured from said central axis of said impeller to said terminal, and wherein said reinforcement ring has a radius Rs , measured from said central axis to said peripheral edge, where Rv is equal to or greater than Rs. 4. The impeller according to claim 3, characterized in that said external terminal end of said at least one vane further comprises a portion having a radius RB; where RB is less than or equal to Rs. The impeller according to claim 4, characterized in that said outwardly extending portion has an arched shape. The impeller according to claim 4, characterized in that said outwardly extending portion has an outer edge which is formed by the intersection of at least two lines. The impeller according to claim 4, characterized in that said at least one vane has a width Wv and wherein said outwardly extending portion has a width WP, where WP is less than or equal to Wv. 8. The impeller according to claim 7, characterized in that the area of said outwardly extending portion is from 30% to about 85% of the area defined by V (RV ~ RB) • 9. The impeller according to claim 1 , characterized in that said outwardly extending portion has an outer edge that is curved or arched. The impeller according to claim 1, characterized in that said outwardly extending portion has an outer edge formed by the intersection of at least two lines. 11. An impeller for a rotodynamic pump, characterized in that it comprises: a reinforcing ring having a central axis and a peripheral edge radially spaced from said central axis, said reinforcing ring having a radius Rs; at least one blade extending axially outwardly from said reinforcing ring and extending a length radially from or near the central axis to said peripheral edge, thereby defining a center line of said at least one blade, which is perpendicular to said central axis, said vane that is secured to said reinforcing ring along the radial extension of said vane, along said reinforcing ring and having an outer terminal end positioned at or near said peripheral edge , wherein said external terminal comprises an outwardly extending portion, having a radius Rv measured from said central axis to a terminal of said outwardly extending portion; and where Rv is equal to or greater than Rs. The impeller according to claim 11, characterized in that it further comprises a second reinforcing ring positioned in parallel with and separated from said reinforcing ring, and wherein said at least one vane extends between said separate reinforcing rings. 13. The impeller according to claim 11, characterized in that said external terminal end of said at l one pallet comprises a portion having a radius RB, wherein RB is equal to Rs. The impeller according to claim 11, characterized in that said external terminal end of said at l one vane, further comprises a portion having a radius RB, wherein RB is less than Rs. The impeller according to claim 11, characterized in that said outwardly extending portion has a cambered or convex shape. The impeller according to claim 11, characterized in that said outwardly extending portion has an outer edge which is curved. The impeller according to claim 11, characterized in that said outwardly extending portion has an outer edge composed of at l two intersecting lines. The impeller according to claim 11, characterized in that said at l one vane has a width Wv, and wherein the shape of said outwardly extending portion is from about 30% to about 85% of the area defined by W (Rv ~ Rs) • The impeller according to claim 13, characterized in that said at l one vane has a width Wv, and wherein the shape of said outwardly extending portion is from about 30% to about 85 % of the area defined by WV (RV-RB) • 20. The impeller according to claim 19, characterized in that said outwardly extending portion has an outer edge which is shaped to produce a selected flow velocity profile for reduce wear on the housing of the pump. The impeller according to claim 2, characterized in that said at l one reinforcing ring has a radius Rs mred from said central axis to said peripheral edge, and wherein said portion extending outwards has a terminal and a radius Rv mred from said central axis of said central axis of said impeller to said terminal and said outwardly extending portion having axial ends defining a radius RB, mred from said at l one end to said central axis, wherein RB is smaller that Rv and Rs, and Rv is less than Rs.