US20170175757A1 - Rotodynamic Pumps that Resist Clogging - Google Patents
Rotodynamic Pumps that Resist Clogging Download PDFInfo
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- US20170175757A1 US20170175757A1 US15/277,795 US201615277795A US2017175757A1 US 20170175757 A1 US20170175757 A1 US 20170175757A1 US 201615277795 A US201615277795 A US 201615277795A US 2017175757 A1 US2017175757 A1 US 2017175757A1
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- Prior art keywords
- cavity
- pump
- shroud
- passage
- pumping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/22—Rotors specially for centrifugal pumps
- F04D29/2261—Rotors specially for centrifugal pumps with special measures
- F04D29/2288—Rotors specially for centrifugal pumps with special measures for comminuting, mixing or separating
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D13/00—Pumping installations or systems
- F04D13/02—Units comprising pumps and their driving means
- F04D13/06—Units comprising pumps and their driving means the pump being electrically driven
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/44—Fluid-guiding means, e.g. diffusers
- F04D29/445—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps
- F04D29/448—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps bladed diffusers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
- F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
- F04D7/04—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous
- F04D7/045—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous with means for comminuting, mixing stirring or otherwise treating
Definitions
- the present invention generally relates to rotodynamic pumps, which also are known as centrifugal pumps, and which in some configurations may be magnetically driven, and more particularly to rotodynamic pumps that resist clogging.
- a rotatable impeller may include a front and/or rear shroud that isolates a front cavity forward of or a rear cavity rearward of the vanes of the impeller, with such cavity being defined by the shroud and the pump casing.
- the outer ends of the vanes of the impeller typically are sized and arranged to be aligned with the inner end of a passage between the pumping cavity and a discharge collector cavity that surrounds the pumping cavity, and the passage generally is smaller in width than the discharge collector cavity.
- solid particles within the fluid being pumped have a tendency to move past the front or rear shroud and accumulate in the front or rear cavity, eventually clogging the pump.
- the pump For rotodynamic pumps that utilize a magnetically driven rotatable impeller, it is common for the pump to additionally include a recirculation path that allows a small percentage of the pump fluid flow to recirculate from the discharge back to the suction side of the pump. This recirculation is used mostly for lubrication and cooling of bushings and for cooling of the canister, which may get hot due to electrical eddy currents generated by the magnetic coupling. The recirculation path also can become clogged by an accumulation of solid particles.
- Some pumps have auxiliary vanes on an opposite side of the front or rear shroud, within the front or rear cavity. Such auxiliary vanes may assist in generating centrifugal force on the solid particles in the fluid within the front or rear cavity, which may prevent the solid particles from flowing into and through a recirculation path by flinging or forcing them outward within the front or rear cavity. Nevertheless, without the ability to evacuate the solid particles, rotodynamic pumps present a risk of clogging when pumping fluid that contains solid particles having a density that is greater than the fluid.
- the present disclosure provides a rotodynamic pump having a design that uses at least one relatively small auxiliary passage to allow the solid particles to exit the at least one front or rear cavity and to enter the discharge collector cavity, so that the solid particles may exit the pump.
- the at least one auxiliary passage has a minimal effect on pump efficiency, while effectively reducing the tendency of clogging the pump.
- the design also can be used in pumps that use dynamic seals between rotating parts or that are magnetically driven.
- the disclosure provides a rotodynamic pump for pumping fluid that resists clogging when pumping fluid that contains solid particles having a density that is greater than the fluid.
- the pump includes a stationary casing having a front portion, a rear portion, an inlet port, an outlet port, a pumping cavity, and a discharge collector cavity located radially outward from the pumping cavity and in fluid communication with the outlet.
- the pump also includes a rotatable impeller assembly having vanes that terminate along a side of at least one of a front shroud or a rear shroud, wherein the at least one of the front shroud or rear shroud separates the pumping cavity from and defines with the casing at least one respective front cavity or rear cavity.
- the stationary casing further includes a primary passage between the pumping cavity and the discharge collector cavity, and at least one auxiliary passage connecting the discharge collector cavity and the at least one front cavity or rear cavity, and wherein rotation of the rotatable impeller assembly imparts centrifugal force on solid particles within fluid in the at least one front cavity or rear cavity and causes the solid particles to move from the at least one front cavity or rear cavity radially outward to and through the at least one auxiliary passage to the discharge collector cavity.
- FIG. 1 provides a side view and a front view of an example rotodynamic pump connected to a motor using an adapter and shaft extension in a close-coupled fashion.
- FIG. 2 provides a quarter-sectioned perspective view of the example pump of FIG. 1 .
- FIG. 3 provides an enlarged closer perspective view of the quarter-sectioned area of FIG. 2 .
- FIG. 4 provides a perspective view of the example pump of FIG. 1 with a sectioned front portion of the casing, showing radially extending auxiliary passages connected to a primary passage between a pumping cavity and a discharge collector cavity.
- FIG. 5 provides a front view of the example pump of FIG. 1 with the sectioned front portion of the casing of FIG. 3 .
- FIG. 6 provides a perspective view of a sectioned front portion of a casing of a second example pump, showing auxiliary passages that are separate apertures between a pumping cavity and a discharge collector cavity.
- FIG. 7 provides a side sectioned view of the casing of FIG. 6 , showing the auxiliary passages that are separate apertures.
- FIG. 8 provides a perspective view of a sectioned front portion of a casing of a third example pump, showing tangentially extending auxiliary passages connected to a primary passage between a pumping cavity and a discharge collector cavity.
- FIG. 9 provides a front view of the third example pump of FIG. 8 with the sectioned front portion of the casing.
- FIG. 10 provides an enlarged closer perspective view of a quarter-sectioned area of a fourth example pump.
- FIG. 11 provides a front perspective view of the fourth example pump of FIG. 10 with a sectioned front portion of the casing, showing radially extending auxiliary passages connected to a primary passage between a rear cavity and a discharge collector cavity.
- FIG. 12 provides a rear perspective view of the corresponding front sectioned portion of the fourth example pump of FIG. 10 showing radially extending auxiliary passages connected to a primary passage between a front cavity and a discharge collector cavity.
- rotodynamic pumps of the present disclosure generally may be embodied within numerous configurations, and it is contemplated and should be understood that such configurations include other rotodynamic pumps whether such pumps utilize dynamic seals between rotating parts or are magnetically driven.
- an example rotodynamic pump 2 is shown connected to a motor adapter 4 that, in turn, is connected to a standard C-face electric motor 6 . More particularly, a first flange 5 of the adapter 4 is connected to the motor 6 by use of a plurality of fasteners 8 , such as threaded screws or other suitable means of connection.
- the pump 2 includes a casing 100 , a discharge port 102 and an inlet port 104 .
- the discharge port 102 is radially facing, while the inlet port 104 is axially facing, although alternative configurations may be utilized.
- the casing 100 includes a rear face 106 that is connected to a second flange 7 of the adapter 4 by use of a plurality of fasteners 10 that pass through apertures in the second flange 7 and engage threaded holes in the casing rear face 106 .
- the casing 100 may be constructed of rigid materials, such as steel, stainless steel, cast iron or other metallic materials, or structural plastics or the like.
- the first example pump 2 also includes a backplate 200 that has an outer flange 202 .
- the backplate outer flange 202 is clamped between the casing 100 and the adapter 4 when connecting the pump 2 to the adapter 4 by installing the fasteners 10 .
- Sealing is provided between the casing 100 and the backplate 200 by an O-ring 13 , although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like.
- the pump 2 also includes a rear cover 300 that has an outer flange 302 .
- the rear cover 300 is connected to the backplate 200 by use of a plurality of fasteners, such as threaded screws that pass through apertures in the backplate 200 and engage threaded holes in a backplate rear face 208 .
- the pump 2 further includes a canister 400 that has an outer flange 402 .
- the canister outer flange 402 is clamped between the backplate 200 and the rear cover 300 when connecting the rear cover 300 to the backplate 200 .
- Sealing is provided between backplate 200 and the canister 400 by an O-ring 16 , although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like.
- the canister 400 also includes a front portion 404 that includes a front face 406 , within a front cavity 408 and an aperture 410 that passes through the front portion 404 .
- the canister 400 may be constructed of rigid materials. It will be appreciated that common materials may be used, such as stainless steel, or low conductivity metals, such as alloy C-22 or alloy C-276, and it could be advantageous to use materials having very low electrical conductivity, such as silicon carbide, ceramic, polymers or the like.
- a nose cap 500 Attached to the canister front portion 404 is a nose cap 500 , which includes a threaded hole 502 , and a rear extended portion 506 that fits into the canister front cavity 408 .
- the nose cap 500 is attached to the canister 400 by a fastener 18 , such as a threaded screw that passes through the aperture 410 in the front portion 404 and engages the threaded hole 502 in the rear of the nose cap 500 .
- a fastener 18 such as a threaded screw that passes through the aperture 410 in the front portion 404 and engages the threaded hole 502 in the rear of the nose cap 500 .
- there is just one fastener 18 but it will be appreciated by one of skill in the art that a plurality of fasteners or other suitable fastening means may be employed.
- the shape of the canister front cavity 408 is not cylindrical, and it corresponds to a non-cylindrical shape of the nose cap extended portion 506 , so as to prevent relative rotation between the nose cap 500 and canister 400 when connected by the fastener 18 . It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of the nose cap 500 . Sealing is provided between the canister 400 and the nose cap 500 by an O-ring 20 , although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like.
- the pump 2 further includes an inner magnet assembly 600 that includes an inner ring 640 which may be connected directly to a shaft, or in this example, to a shaft extension 620 .
- the inner ring 640 has a central threaded aperture 642 and the shaft extension 620 has a mating externally threaded front portion 622 , which is used to connect the inner ring 640 to the shaft extension 620 .
- the shaft extension 620 and inner ring 640 are separate pieces, but it will be appreciated that they could be combined, so as to be a single piece, or a different method of connection may be used.
- the inner ring 640 may be constructed of rigid materials, but is preferably constructed of a material with high magnetic permeability, such as iron, carbon steel or the like.
- the shaft extension 620 of this example includes an inner opening 624 that slidably receives a shaft 22 of the motor 6 .
- the shaft extension 620 also includes a keyway 626 and one or more threaded apertures 628 .
- a key 24 is positioned in the shaft extension keyway 626 and engages with a keyway 26 of the motor shaft 22 , to provide a positive rotational connection between the shaft extension 620 and the motor shaft 22 .
- One or more setscrews 28 are positioned in the shaft extension threaded apertures 628 and are tightened against the keyway 26 of the motor shaft 22 , to provide a positive axial connection between the shaft extension 620 and the motor shaft 22 .
- the inner ring 640 includes an outer surface to which are connected twenty-four magnet segments 646 , although it will be appreciated that one may have an embodiment with a different quantity of magnet segments.
- the magnet segments 646 are radially charged and are positioned with alternating polarity.
- the magnet segments 646 are rigidly connected to the inner ring 640 using an adhesive, although alternative suitable means of connection may be used, such as use of fasteners or the like.
- this example embodiment includes an inner magnet sleeve 648 having a thin cylindrical portion that closely fits over and covers the outer surfaces of the magnet segments 646 .
- the first example pump 2 also includes a rotatable impeller assembly 700 that includes an impeller 702 .
- the impeller 702 includes a rear opening 704 , which receives an outer magnet assembly 705 .
- the outer magnet assembly 705 includes an outer ring 706 having an inner surface to which are connected twenty-four magnet segments 710 , which corresponds to the number of magnet segments connected to the inner ring 640 , although it will be appreciated that one may have an embodiment with a greater or lesser quantity of magnet segments.
- the magnet segments 710 are radially charged and are positioned with alternating polarity.
- the magnet segments 710 are rigidly connected to the outer ring 706 using an adhesive, although alternative suitable means of connection may be used, such as use of fasteners or the like.
- An impeller magnet sleeve 712 is included having a thin cylindrical portion that closely fits along and covers the inner surfaces of the magnet segments 710 .
- the impeller magnet sleeve 712 also includes a rear flange.
- the impeller magnet sleeve 712 is sealingly connected to the impeller 702 by continuous weld joints located at an outer end of the rear flange and at a front end of the cylindrical portion, although it will be appreciated by one of skill in the art that other methods of connection may be used, such as liquid adhesive, gaskets, O-rings or the like.
- the impeller 702 has a central opening 724 that includes one or more grooves 726 .
- a bushing 800 is received in the impeller central opening 724 , and one or more O-rings are positioned between an outer surface of the bushing 800 and the grooves 726 in the central opening 724 of the impeller 702 .
- the bushing outer surface is slightly smaller than the impeller central opening 724 , and the O-rings are not intended to provide sealing between the two surfaces.
- the rotor or impeller 702 may be constructed of rigid materials, such as steel, stainless steel, cast iron or other metallic materials, or structural plastics or the like.
- the outer ring 706 may be constructed of rigid materials, but preferably is constructed of a material with high magnetic permeability, such as iron, carbon steel or the like.
- the impeller 702 further includes a rear surface 728 that includes one or more threaded holes 730 .
- An impeller rear ring 732 is connected to the impeller rear surface 728 by at least one fastener 32 , such as by a plurality of screws that pass through apertures in the impeller rear ring 732 and engage the threaded holes 730 in the impeller 702 .
- the bushing 800 includes a rear portion with a shape that is not cylindrical, and it corresponds to a non-cylindrical central opening in the impeller rear ring 732 to prevent relative rotation between the bushing 800 , the impeller rear ring 732 and the impeller 702 . It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of the bushing 800 .
- the first example pump 2 also includes a stationary bearing sleeve 806 that has a cylindrical shape.
- the front portion 404 of the canister 400 includes an outer surface 412 having at least one groove 414 .
- the bearing sleeve 806 is positioned over the outer surface 412 of the canister front portion 404 , and at least one O-ring is positioned between the outer surface groove 414 of the canister front portion 404 and an inner surface of the bearing sleeve 806 .
- two O-rings are received in two grooves 414 .
- the outer surface 412 of the canister front portion 404 is slightly smaller than the inner surface of the bearing sleeve 806 .
- the canister 400 and the bearing sleeve 806 may be made of materials with different rates of thermal expansion, then the size or extent of the clearance between the canister 400 and the bearing sleeve 806 will change.
- the O-rings are not intended to seal, but the compression of the O-rings in the grooves 414 will accommodate this clearance change and will maintain a concentric relationship between the canister 400 and the bearing sleeve 806 .
- the outer surface of the stationary bearing sleeve 806 is slightly smaller than the inner surface of the impeller bushing 800 .
- the rotatable impeller assembly 700 rotates in engagement with and is supported by the outer surface of the stationary bearing sleeve 806 .
- the pump 2 of this example embodiment also includes a stationary rear thrust washer 814 having a central opening with a shape that is not cylindrical.
- the canister 400 includes a center portion having a non-cylindrical shape that corresponds to the shape of the central opening of the rear thrust washer 814 , to prevent relative rotation between the canister 400 and rear thrust washer 814 . It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of the thrust washer 814 .
- the canister 400 includes a center wall 418 that has a front surface 420 . The rear thrust washer 814 is brought into position over the canister front portion 416 and moved rearward against the front surface 420 of the canister center wall 418 .
- the pump 2 includes a stationary front thrust washer 818 with a central opening having a shape that is not cylindrical.
- the nose cap 500 includes a center portion having a non-cylindrical shape that corresponds to the shape of the central opening of the front thrust washer 818 to prevent relative rotation between the nose cap 500 and front thrust washer 818 . It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of the front thrust washer 818 .
- the nose cap 500 has a front flange 510 .
- the front flange 510 also has a rear surface 512 .
- the front thrust washer 818 is positioned over the center portion of the nose cap 500 and against the rear surface 512 of the front flange 510 of the nose cap 500 .
- the impeller bushing 800 has a length that is slightly shorter than the length of the bearing sleeve 806 .
- the bearing sleeve 806 is positioned between the rear thrust washer 814 and the front thrust washer 818 , creating a gap equal to the length of the bearing sleeve 806 .
- the rotatable impeller assembly 700 is positioned such that the impeller bushing 800 is in the gap between the rear thrust washer 814 and the front thrust washer 818 .
- the impeller bushing 800 has a front face and a rear face.
- the rotatable impeller assembly 700 may experience a rear thrust force, pushing the rotatable impeller assembly 700 rearward and causing the bushing rear face to rotatably engage the front face of the rear thrust washer 814 and to restrict rearward motion of the rotatable impeller assembly 700 .
- the rotatable impeller assembly 700 may experience a forward thrust force, pushing the rotatable impeller assembly 700 forward and causing the bushing front face to rotatably engage the rear face of the front thrust washer 818 and to restrict forward motion of the rotatable impeller assembly 700 .
- the bushing 800 may include one or more grooves on the front face, rear face and inner surface for lubrication.
- the canister 400 includes a thin cylindrical portion 422 having an inner surface that is slightly larger than the outer surface of the inner magnet assembly 600 , and having an outer surface that is slightly smaller than the inner surface of the impeller magnet sleeve 712 .
- the casing 100 , backplate 200 , canister 400 and nose cap 500 all remain stationary, are sealingly connected, and together form a sealed chamber rearward of the canister 400 .
- the inner magnet segments 646 of the inner magnet assembly 600 are axially aligned with the impeller magnet segments 710 of the outer magnet assembly 705 .
- the alternating polarity of the inner magnet segments 646 creates an inner magnetic field
- the alternating polarity of the impeller magnet segments 710 creates an outer magnetic field.
- the impeller 702 of the rotatable impeller assembly 700 includes a plurality of vanes 740 that terminate along one side of a shroud 746 , which in this example is the front side of a rear shroud.
- the front side of the shroud 746 has a surface 754 and in this example the shroud 746 is at the rear of the vanes 740 .
- the casing 100 includes a discharge collector cavity 108 that is fluidly connected to the casing discharge port 102 .
- the rotation of the impeller vanes 740 causes a pumping action in the location of the vanes 740 , which is considered herein to be a pumping cavity 750 , and moves fluid into the pump through the casing inlet port 104 , radially outward through a primary passage 752 to the discharge collector cavity 108 , and out of the pump through the discharge port 102 .
- the shroud 746 separates the pumping cavity 750 from and defines with the casing 100 a rear cavity 110 .
- the rear cavity 110 is partially blocked from the discharge collector cavity 108 by the impeller shroud 746 .
- the casing 100 includes at least one auxiliary passage 112 that connects the discharge collector cavity 108 and the rear cavity 110 .
- the auxiliary passage 112 expands the width of the primary passage 752 at the location of the auxiliary passage 112 .
- the rotatable impeller assembly could include a front shroud, a rear shroud, or both a front and rear shroud.
- the at least one shroud has a surface 754 on the side along which the vanes 740 of the rotatable impeller assembly 700 terminate, and the surface 754 of the shroud 746 is substantially aligned with a surface 756 that defines the primary passage 752 between the pumping cavity 750 and the discharge collector cavity 108 .
- the primary passage 752 has a width at its inner end and the rotatable impeller assembly vanes 740 have outer ends sized to span a distance D that substantially aligns the outer end of the vanes 740 with the width at the inner end of the primary passage 752 .
- the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from the shroud 746 and vanes 740 to the primary passage 752 .
- rotation of the rotatable impeller assembly 700 causes rotation of the fluid within the rear cavity 110 , which imparts centrifugal force on any solid particles that may be within the fluid in the rear cavity 110 , and causes the solid particles to move from the casing rear cavity 110 radially outward to and through the at least one auxiliary passage 112 to the discharge collector cavity 108 .
- a casing having at least one such auxiliary passage 112 helps to resist clogging of the pump 2 by avoiding the accumulation of solid particles in the rear cavity 110 behind the shroud 746 of the rotatable impeller assembly 700 .
- the rotatable impeller assembly 700 also may include at least one auxiliary vane located on the shroud 746 and within the rear cavity 110 , which would further enhance the centrifugal force applied by the rotation of the rotatable impeller assembly 700 and assist in imparting centrifugal force on the solid particles within the fluid in the rear cavity 110 .
- the movement of the fluid radially inward in the rear cavity 110 may help provide fluid for a recirculation passageway behind the rotatable impeller assembly 700 that begins at the discharge collector cavity 108 , where the pressure is high, extends between stationary and rotating surfaces, and ends in front of the nose cap 500 at the inlet port 104 , where the pressure is low.
- the passageway is dynamic, since every part is bounded by a combination of stationary surfaces and rotating surfaces.
- the stationary surfaces are on the casing 100 , backplate 200 , canister 400 , rear thrust washer 814 , bearing sleeve 806 , front thrust washer 818 and nose cap 500 .
- the rotating surfaces are on the rotatable impeller assembly 700 .
- the second example pump 2 a is similar to the first example pump 2 in many ways and essentially uses the drive, sealing, rotatable impeller assembly, and other rear structures of the first example pump 2 , but differs in that it includes an alternative pump casing 100 a, which is shown in a perspective sectioned view in FIG. 6 and in a side sectioned view in FIG. 7 .
- an alternative pump casing 100 a which is shown in a perspective sectioned view in FIG. 6 and in a side sectioned view in FIG. 7 .
- this alternative second example configuration includes at least one auxiliary passage 112 a in the form of a separate aperture. More particularly, the second example would have three auxiliary passages 112 a in the form of separate apertures that are spaced equally around the discharge collecting cavity 108 and that connect a rear cavity 110 to the collector discharge cavity 108 .
- the rotatable impeller assembly 700 still has an impeller 702 having a plurality of vanes 740 .
- the vanes 740 terminate at a side of a shroud 746 that has a surface 754 .
- the primary passage 752 has a width at its inner end and the vanes 740 of the rotatable impeller assembly 700 have outer ends sized to span a distance D that substantially aligns the outer end of the vanes 740 with the width at the inner end of the primary passage 752 .
- the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from the shroud 746 and vanes 740 to the primary passage 752 .
- the surface 754 of the shroud 746 is substantially aligned with a surface 756 that defines the primary passage 752 between the pumping cavity and the discharge collector cavity 108 .
- the main difference between the configuration and components of the second example pump 2 a relative to the first example pump 2 is the inclusion of at least one auxiliary passage in the form of an aperture 112 a, instead of at least one auxiliary passage in the form of a slot 112 .
- the auxiliary passages 112 a in the form of apertures also would serve to resist pump clogging by allowing solid particles to pass from the rear cavity 110 to the collector discharge cavity 108 .
- the third example pump 2 b is similar to the first example pump 2 in many ways and essentially uses the drive, sealing, rotatable impeller assembly, and other rear structures of the first example pump 2 , but differs in that it includes an alternative pump casing 100 b, which is shown in a perspective sectioned view in FIG. 8 and in a front sectioned view in FIG. 9 .
- an alternative pump casing 100 b which is shown in a perspective sectioned view in FIG. 8 and in a front sectioned view in FIG. 9 .
- this alternative third example configuration includes at least one auxiliary passage 112 b in the form of a similar groove, slot or channel, but extending tangentially outward, while being connected to and effectively expanding the width of the primary passage 752 at the location of the auxiliary passage 112 b.
- the third example would have three auxiliary passages 112 b in the form of separate tangentially extending slots that are spaced equally around the discharge collecting cavity 108 and that connect a rear cavity 110 to the collector discharge cavity 108 .
- the rotatable impeller assembly 700 still has an impeller 702 having a plurality of vanes 740 .
- the vanes 740 terminate at a side of a shroud 746 that has a surface 754 .
- the primary passage 752 has a width at its inner end and the vanes 740 of the rotatable impeller assembly 700 have outer ends sized to span a distance D that substantially aligns the outer end of the vanes 740 with the width at the inner end of the primary passage 752 .
- the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from the shroud 746 and vanes 740 to the primary passage 752 .
- the surface 754 of the shroud 746 is substantially aligned with a surface 756 that defines the primary passage 752 between the pumping cavity and the discharge collector cavity 108 .
- the main difference between the configuration and components of the third example pump 2 b relative to the first example pump 2 is the inclusion of at least one auxiliary passage in the form of a slot 112 b that extends tangentially, instead of at least one auxiliary passage in the form of a slot 112 that extends more directly radially.
- auxiliary passages 112 b extending tangentially also would serve to resist pump clogging by allowing solid particles to pass from the rear cavity 110 to the collector discharge cavity 108 , and while radial and tangential angles have been shown, it will be appreciated that the auxiliary passages could extend outward at any angle.
- FIGS. 10-12 a fourth example pump 2 c is shown, which is similar in many ways to the first example pump 2 and essentially uses the drive, sealing and other rear structures of the first example pump 2 . Given the similarity between many of the components of the first and fourth example pumps, to avoid redundancy and unnecessary length, this description and the accompanying drawings, focus on the most relevant differences between the examples.
- the fourth example pump 2 c differs in that it includes an alternative casing 100 c and an alternative rotatable impeller assembly 700 c, having an alternative impeller 702 c, and having a rear shroud 746 and a front shroud 746 c, which are shown in an enlarged closer perspective view of a quarter-sectioned area of the fourth example pump in FIG. 10 , in a front perspective view of a front sectioned portion in FIG. 11 , and in a rear perspective view of the corresponding front sectioned portion of the fourth example pump 2 c.
- the fourth example pump 2 c includes at least one auxiliary passage 112 that is similar to the at least one auxiliary passage 112 of the first example pump 2 in that it is in the form of a groove, slot or channel, and extends radially outward, while being connected to and effectively expanding the width of the primary passage 752 at the location of the auxiliary passage 112 , so as to connect the rear cavity 110 with the discharge collector cavity 108 .
- the fourth example pump 2 c also includes at least one auxiliary passage 112 c that is somewhat similar to the at least one auxiliary passage 112 in that it is in the form of a groove, slot or channel, and extends radially outward, but it is connected to and effectively expands the width of the primary passage 752 at the location of the auxiliary passage 112 c, so as to connect a front cavity 110 c that is forward of the shroud 746 c ′ with the discharge collector cavity 108 .
- the fourth example pump 2 c would have three auxiliary passages 112 in the form of radially extending slots that are spaced equally around the discharge collecting cavity 108 and that connect a rear cavity 110 to the collector discharge cavity 108 , while also having have three auxiliary passages 112 c in the form of radially extending slots that are spaced equally around the discharge collecting cavity 108 and that connect a front cavity 110 to the collector discharge cavity 108 .
- the alternative impeller 702 c of the rotatable impeller assembly 700 c of the fourth example pump 2 c includes a plurality of vanes 740 c having outer ends that extend between the rear shroud 746 and the front shroud 746 c.
- the outer ends of the vanes 740 c terminate at their rear at a front side of the rear shroud 746 that has a surface 754 , and terminate at their front at a rear side of the front shroud 746 c that has a surface 754 c.
- the casing 100 c includes a discharge collector cavity 108 that is fluidly connected to the casing discharge port 102 .
- the rotation of the impeller vanes 740 c causes a pumping action in the location of the vanes 740 c, which is considered herein to be a pumping cavity 750 c, and moves fluid into the pump through the casing inlet port 104 , radially outward through a primary passage 752 to the discharge collector cavity 108 , and out of the pump through the discharge port 102 .
- the primary passage 752 has a width at its inner end and the vanes 740 c of the rotatable impeller assembly 700 c have outer ends sized to span a distance D that substantially aligns the outer end of the vanes 740 c with the width at the inner end of the primary passage 752 .
- the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from the rear shroud 746 and front shroud 746 c and vanes 740 c to the primary passage 752 .
- the surface 754 of the shroud 746 is substantially aligned with a surface 756 that defines one side of the primary passage 752 between the pumping cavity and the discharge collector cavity 108 , with surface 754 c of the shroud 746 c similarly being substantially aligned with a surface 756 c that defines the other side of the primary passage 752 .
- the main differences between the configuration and components of the fourth example pump 2 c relative to the first example pump 2 is the inclusion of at least a rear shroud 746 and a front shroud 746 c, which define with the casing 100 c a rear cavity 110 rearward of the rear shroud 746 and a front cavity 110 c forward of the front shroud 746 c, and the respective inclusion of at least one auxiliary passage 112 in the form of a slot that extends radially and connects the rear cavity 110 with the discharge collector cavity 108 , as well as at least one auxiliary passage 112 c in the form of a slot that extends radially and connects the front cavity 110 c with the discharge collector cavity 108 .
- the auxiliary passages 112 and 112 c extending radially also would serve to resist pump clogging by allowing solid particles to pass from the respective rear cavity 110 and front cavity 110 c to the collector discharge cavity 108 .
- pumps constructed in accordance with this disclosure may include a number of structural aspects that provide advantages over conventional constructions, depending upon the specific design chosen.
- a pump constructed in accordance with the present disclosure may be provided in various configurations. Any variety of suitable materials of construction, configurations, shapes and sizes for the components and methods of connecting the components may be utilized to meet the particular needs and requirements of an end user. Indeed, pumps in accordance with the present disclosure may include interior surfaces that are constructed of specific materials and/or have particular surface finishes wherein the interior surfaces permit use of the pumps in hygienic applications where microbial growth must be prevented. It will be apparent to those skilled in the art that various modifications can be made in the design and construction of such pumps without departing from the scope or spirit of the claimed subject matter, and that the claims are not limited to the preferred embodiment illustrated herein. It also will be appreciated that some aspects of the example embodiment are discussed in a simplified manner, as the invention is capable of being implemented in rotodynamic pumps, whether such pumps include dynamic seals between rotating parts or are magnetically driven.
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Abstract
The disclosure provides a rotodynamic pump that resists clogging when pumping fluid that contains solid particles having a density that is greater than the fluid. The pump also includes a rotatable impeller assembly having at least one of a front shroud or a rear shroud that separates the pumping cavity from and defines with a casing at least one respective front cavity or rear cavity. The pump casing also has a primary passage between the pumping cavity and the discharge collector cavity, and at least one auxiliary passage connecting the discharge collector cavity and the at least one front cavity or rear cavity, wherein rotation of the rotatable impeller assembly causes the solid particles to move from the at least one front cavity or rear cavity radially outward to and through the at least one auxiliary passage to the discharge collector cavity.
Description
- Field of the Invention
- The present invention generally relates to rotodynamic pumps, which also are known as centrifugal pumps, and which in some configurations may be magnetically driven, and more particularly to rotodynamic pumps that resist clogging.
- Description of the Related Art
- Pumped fluids often contain solid particles or particulates having a density that is greater than the fluid. The solid particles can abrade bushings and cause clogging of a rotodynamic pump. The pumping cavities of prior art pumps normally are designed to be separated from a casing discharge collector cavity, presumably to maintain the best pump efficiency. A rotatable impeller may include a front and/or rear shroud that isolates a front cavity forward of or a rear cavity rearward of the vanes of the impeller, with such cavity being defined by the shroud and the pump casing. To obtain the smoothest flow and best pump efficiency, the outer ends of the vanes of the impeller typically are sized and arranged to be aligned with the inner end of a passage between the pumping cavity and a discharge collector cavity that surrounds the pumping cavity, and the passage generally is smaller in width than the discharge collector cavity. However, with such a configuration, solid particles within the fluid being pumped have a tendency to move past the front or rear shroud and accumulate in the front or rear cavity, eventually clogging the pump.
- For rotodynamic pumps that utilize a magnetically driven rotatable impeller, it is common for the pump to additionally include a recirculation path that allows a small percentage of the pump fluid flow to recirculate from the discharge back to the suction side of the pump. This recirculation is used mostly for lubrication and cooling of bushings and for cooling of the canister, which may get hot due to electrical eddy currents generated by the magnetic coupling. The recirculation path also can become clogged by an accumulation of solid particles.
- Some pumps have auxiliary vanes on an opposite side of the front or rear shroud, within the front or rear cavity. Such auxiliary vanes may assist in generating centrifugal force on the solid particles in the fluid within the front or rear cavity, which may prevent the solid particles from flowing into and through a recirculation path by flinging or forcing them outward within the front or rear cavity. Nevertheless, without the ability to evacuate the solid particles, rotodynamic pumps present a risk of clogging when pumping fluid that contains solid particles having a density that is greater than the fluid.
- The present disclosure provides a rotodynamic pump having a design that uses at least one relatively small auxiliary passage to allow the solid particles to exit the at least one front or rear cavity and to enter the discharge collector cavity, so that the solid particles may exit the pump. Advantageously, the at least one auxiliary passage has a minimal effect on pump efficiency, while effectively reducing the tendency of clogging the pump. The design also can be used in pumps that use dynamic seals between rotating parts or that are magnetically driven.
- In a first aspect, the disclosure provides a rotodynamic pump for pumping fluid that resists clogging when pumping fluid that contains solid particles having a density that is greater than the fluid. The pump includes a stationary casing having a front portion, a rear portion, an inlet port, an outlet port, a pumping cavity, and a discharge collector cavity located radially outward from the pumping cavity and in fluid communication with the outlet. The pump also includes a rotatable impeller assembly having vanes that terminate along a side of at least one of a front shroud or a rear shroud, wherein the at least one of the front shroud or rear shroud separates the pumping cavity from and defines with the casing at least one respective front cavity or rear cavity. The stationary casing further includes a primary passage between the pumping cavity and the discharge collector cavity, and at least one auxiliary passage connecting the discharge collector cavity and the at least one front cavity or rear cavity, and wherein rotation of the rotatable impeller assembly imparts centrifugal force on solid particles within fluid in the at least one front cavity or rear cavity and causes the solid particles to move from the at least one front cavity or rear cavity radially outward to and through the at least one auxiliary passage to the discharge collector cavity.
- It is to be understood that both the foregoing general description and the following detailed description are exemplary and provided for purposes of explanation only, and are not restrictive of the subject matter claimed. Further features and objects of the present disclosure will become more fully apparent in the following description of the preferred embodiments and from the appended claims.
- In describing the preferred embodiments, reference is made to the accompanying drawing figures wherein like parts have like reference numerals, and wherein:
-
FIG. 1 provides a side view and a front view of an example rotodynamic pump connected to a motor using an adapter and shaft extension in a close-coupled fashion. -
FIG. 2 provides a quarter-sectioned perspective view of the example pump ofFIG. 1 . -
FIG. 3 provides an enlarged closer perspective view of the quarter-sectioned area ofFIG. 2 . -
FIG. 4 provides a perspective view of the example pump ofFIG. 1 with a sectioned front portion of the casing, showing radially extending auxiliary passages connected to a primary passage between a pumping cavity and a discharge collector cavity. -
FIG. 5 provides a front view of the example pump ofFIG. 1 with the sectioned front portion of the casing ofFIG. 3 . -
FIG. 6 provides a perspective view of a sectioned front portion of a casing of a second example pump, showing auxiliary passages that are separate apertures between a pumping cavity and a discharge collector cavity. -
FIG. 7 provides a side sectioned view of the casing ofFIG. 6 , showing the auxiliary passages that are separate apertures. -
FIG. 8 provides a perspective view of a sectioned front portion of a casing of a third example pump, showing tangentially extending auxiliary passages connected to a primary passage between a pumping cavity and a discharge collector cavity. -
FIG. 9 provides a front view of the third example pump ofFIG. 8 with the sectioned front portion of the casing. -
FIG. 10 provides an enlarged closer perspective view of a quarter-sectioned area of a fourth example pump. -
FIG. 11 provides a front perspective view of the fourth example pump ofFIG. 10 with a sectioned front portion of the casing, showing radially extending auxiliary passages connected to a primary passage between a rear cavity and a discharge collector cavity. -
FIG. 12 provides a rear perspective view of the corresponding front sectioned portion of the fourth example pump ofFIG. 10 showing radially extending auxiliary passages connected to a primary passage between a front cavity and a discharge collector cavity. - It should be understood that the drawings are not to scale. While some mechanical details of example rotodynamic pumps, including details of fastening means and other plan and section views of the particular components, have not been shown, such details are considered to be within the comprehension of those skilled in the art in light of the present disclosure. It also should be understood that the present disclosure and claims are not limited to the preferred embodiments illustrated.
- Referring generally to
FIGS. 1-12 and the written disclosure herein, it will be appreciated that rotodynamic pumps of the present disclosure generally may be embodied within numerous configurations, and it is contemplated and should be understood that such configurations include other rotodynamic pumps whether such pumps utilize dynamic seals between rotating parts or are magnetically driven. - Referring to a preferred first example embodiment, in
FIGS. 1-5 , an examplerotodynamic pump 2 is shown connected to amotor adapter 4 that, in turn, is connected to a standard C-faceelectric motor 6. More particularly, afirst flange 5 of theadapter 4 is connected to themotor 6 by use of a plurality offasteners 8, such as threaded screws or other suitable means of connection. Thepump 2 includes acasing 100, adischarge port 102 and aninlet port 104. In this example embodiment, thedischarge port 102 is radially facing, while theinlet port 104 is axially facing, although alternative configurations may be utilized. Thecasing 100 includes arear face 106 that is connected to asecond flange 7 of theadapter 4 by use of a plurality offasteners 10 that pass through apertures in thesecond flange 7 and engage threaded holes in the casingrear face 106. Thecasing 100 may be constructed of rigid materials, such as steel, stainless steel, cast iron or other metallic materials, or structural plastics or the like. - The
first example pump 2 also includes abackplate 200 that has anouter flange 202. The backplateouter flange 202 is clamped between thecasing 100 and theadapter 4 when connecting thepump 2 to theadapter 4 by installing thefasteners 10. Sealing is provided between thecasing 100 and thebackplate 200 by an O-ring 13, although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like. - The
pump 2 also includes arear cover 300 that has anouter flange 302. Therear cover 300 is connected to thebackplate 200 by use of a plurality of fasteners, such as threaded screws that pass through apertures in thebackplate 200 and engage threaded holes in a backplaterear face 208. - While the present disclosure is applicable to rotodynamic pumps more generally, the
first example pump 2 also happens to be magnetically driven. As such, thepump 2 further includes acanister 400 that has anouter flange 402. The canisterouter flange 402 is clamped between thebackplate 200 and therear cover 300 when connecting therear cover 300 to thebackplate 200. Sealing is provided betweenbackplate 200 and thecanister 400 by an O-ring 16, although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like. Thecanister 400 also includes afront portion 404 that includes afront face 406, within afront cavity 408 and anaperture 410 that passes through thefront portion 404. Thecanister 400 may be constructed of rigid materials. It will be appreciated that common materials may be used, such as stainless steel, or low conductivity metals, such as alloy C-22 or alloy C-276, and it could be advantageous to use materials having very low electrical conductivity, such as silicon carbide, ceramic, polymers or the like. - Attached to the
canister front portion 404 is anose cap 500, which includes a threadedhole 502, and a rear extendedportion 506 that fits into the canisterfront cavity 408. Thenose cap 500 is attached to thecanister 400 by afastener 18, such as a threaded screw that passes through theaperture 410 in thefront portion 404 and engages the threadedhole 502 in the rear of thenose cap 500. In this example embodiment, there is just onefastener 18, but it will be appreciated by one of skill in the art that a plurality of fasteners or other suitable fastening means may be employed. The shape of thecanister front cavity 408 is not cylindrical, and it corresponds to a non-cylindrical shape of the nose cap extendedportion 506, so as to prevent relative rotation between thenose cap 500 andcanister 400 when connected by thefastener 18. It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of thenose cap 500. Sealing is provided between thecanister 400 and thenose cap 500 by an O-ring 20, although other methods of sealing may be employed, such as use of a gasket, liquid sealant or the like. - The
pump 2 further includes aninner magnet assembly 600 that includes aninner ring 640 which may be connected directly to a shaft, or in this example, to ashaft extension 620. Theinner ring 640 has a central threadedaperture 642 and theshaft extension 620 has a mating externally threadedfront portion 622, which is used to connect theinner ring 640 to theshaft extension 620. In this example embodiment, theshaft extension 620 andinner ring 640 are separate pieces, but it will be appreciated that they could be combined, so as to be a single piece, or a different method of connection may be used. Theinner ring 640 may be constructed of rigid materials, but is preferably constructed of a material with high magnetic permeability, such as iron, carbon steel or the like. - The
shaft extension 620 of this example includes aninner opening 624 that slidably receives ashaft 22 of themotor 6. Theshaft extension 620 also includes akeyway 626 and one or more threadedapertures 628. A key 24 is positioned in theshaft extension keyway 626 and engages with akeyway 26 of themotor shaft 22, to provide a positive rotational connection between theshaft extension 620 and themotor shaft 22. One ormore setscrews 28 are positioned in the shaft extension threadedapertures 628 and are tightened against thekeyway 26 of themotor shaft 22, to provide a positive axial connection between theshaft extension 620 and themotor shaft 22. - The
inner ring 640 includes an outer surface to which are connected twenty-fourmagnet segments 646, although it will be appreciated that one may have an embodiment with a different quantity of magnet segments. Themagnet segments 646 are radially charged and are positioned with alternating polarity. Themagnet segments 646 are rigidly connected to theinner ring 640 using an adhesive, although alternative suitable means of connection may be used, such as use of fasteners or the like. Although not required, this example embodiment includes aninner magnet sleeve 648 having a thin cylindrical portion that closely fits over and covers the outer surfaces of themagnet segments 646. - The
first example pump 2 also includes arotatable impeller assembly 700 that includes animpeller 702. Theimpeller 702 includes arear opening 704, which receives anouter magnet assembly 705. Theouter magnet assembly 705 includes anouter ring 706 having an inner surface to which are connected twenty-fourmagnet segments 710, which corresponds to the number of magnet segments connected to theinner ring 640, although it will be appreciated that one may have an embodiment with a greater or lesser quantity of magnet segments. Themagnet segments 710 are radially charged and are positioned with alternating polarity. Themagnet segments 710 are rigidly connected to theouter ring 706 using an adhesive, although alternative suitable means of connection may be used, such as use of fasteners or the like. Animpeller magnet sleeve 712 is included having a thin cylindrical portion that closely fits along and covers the inner surfaces of themagnet segments 710. Theimpeller magnet sleeve 712 also includes a rear flange. Theimpeller magnet sleeve 712 is sealingly connected to theimpeller 702 by continuous weld joints located at an outer end of the rear flange and at a front end of the cylindrical portion, although it will be appreciated by one of skill in the art that other methods of connection may be used, such as liquid adhesive, gaskets, O-rings or the like. - The
impeller 702 has acentral opening 724 that includes one ormore grooves 726. Abushing 800 is received in the impellercentral opening 724, and one or more O-rings are positioned between an outer surface of thebushing 800 and thegrooves 726 in thecentral opening 724 of theimpeller 702. The bushing outer surface is slightly smaller than the impellercentral opening 724, and the O-rings are not intended to provide sealing between the two surfaces. Rather, in the event that the operating temperature may vary, and thebushing 800 and theimpeller 702 may be made of materials with different rates of thermal expansion, then the size or extent of the clearance between thebushing 800 andimpeller 702 will change and the compression of the O-rings of this example embodiment will accommodate this clearance change and will maintain a concentric relationship between thebushing 800 and theimpeller 702. The rotor orimpeller 702 may be constructed of rigid materials, such as steel, stainless steel, cast iron or other metallic materials, or structural plastics or the like. Theouter ring 706 may be constructed of rigid materials, but preferably is constructed of a material with high magnetic permeability, such as iron, carbon steel or the like. - The
impeller 702 further includes arear surface 728 that includes one or more threadedholes 730. An impellerrear ring 732 is connected to the impellerrear surface 728 by at least onefastener 32, such as by a plurality of screws that pass through apertures in the impellerrear ring 732 and engage the threadedholes 730 in theimpeller 702. Thebushing 800 includes a rear portion with a shape that is not cylindrical, and it corresponds to a non-cylindrical central opening in the impellerrear ring 732 to prevent relative rotation between thebushing 800, the impellerrear ring 732 and theimpeller 702. It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of thebushing 800. - The
first example pump 2 also includes astationary bearing sleeve 806 that has a cylindrical shape. Thefront portion 404 of thecanister 400 includes anouter surface 412 having at least onegroove 414. Thebearing sleeve 806 is positioned over theouter surface 412 of thecanister front portion 404, and at least one O-ring is positioned between theouter surface groove 414 of thecanister front portion 404 and an inner surface of thebearing sleeve 806. In this example embodiment, two O-rings are received in twogrooves 414. Theouter surface 412 of thecanister front portion 404 is slightly smaller than the inner surface of thebearing sleeve 806. In the event that the operating temperature may vary and thecanister 400 and thebearing sleeve 806 may be made of materials with different rates of thermal expansion, then the size or extent of the clearance between thecanister 400 and thebearing sleeve 806 will change. The O-rings are not intended to seal, but the compression of the O-rings in thegrooves 414 will accommodate this clearance change and will maintain a concentric relationship between thecanister 400 and thebearing sleeve 806. - The outer surface of the
stationary bearing sleeve 806 is slightly smaller than the inner surface of theimpeller bushing 800. Therotatable impeller assembly 700 rotates in engagement with and is supported by the outer surface of thestationary bearing sleeve 806. - The
pump 2 of this example embodiment also includes a stationaryrear thrust washer 814 having a central opening with a shape that is not cylindrical. Thecanister 400 includes a center portion having a non-cylindrical shape that corresponds to the shape of the central opening of therear thrust washer 814, to prevent relative rotation between thecanister 400 andrear thrust washer 814. It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of thethrust washer 814. Thecanister 400 includes acenter wall 418 that has afront surface 420. Therear thrust washer 814 is brought into position over the canister front portion 416 and moved rearward against thefront surface 420 of thecanister center wall 418. - The
pump 2 includes a stationaryfront thrust washer 818 with a central opening having a shape that is not cylindrical. Thenose cap 500 includes a center portion having a non-cylindrical shape that corresponds to the shape of the central opening of thefront thrust washer 818 to prevent relative rotation between thenose cap 500 andfront thrust washer 818. It will be appreciated that other configurations or fastening methods may be used to prevent relative rotation of thefront thrust washer 818. Thenose cap 500 has afront flange 510. Thefront flange 510 also has arear surface 512. Thefront thrust washer 818 is positioned over the center portion of thenose cap 500 and against therear surface 512 of thefront flange 510 of thenose cap 500. - The
impeller bushing 800 has a length that is slightly shorter than the length of thebearing sleeve 806. Thebearing sleeve 806 is positioned between therear thrust washer 814 and thefront thrust washer 818, creating a gap equal to the length of thebearing sleeve 806. Therotatable impeller assembly 700 is positioned such that theimpeller bushing 800 is in the gap between therear thrust washer 814 and thefront thrust washer 818. Theimpeller bushing 800 has a front face and a rear face. Under some pump operating conditions, therotatable impeller assembly 700 may experience a rear thrust force, pushing therotatable impeller assembly 700 rearward and causing the bushing rear face to rotatably engage the front face of therear thrust washer 814 and to restrict rearward motion of therotatable impeller assembly 700. Under other pump operating conditions, therotatable impeller assembly 700 may experience a forward thrust force, pushing therotatable impeller assembly 700 forward and causing the bushing front face to rotatably engage the rear face of thefront thrust washer 818 and to restrict forward motion of therotatable impeller assembly 700. Thebushing 800 may include one or more grooves on the front face, rear face and inner surface for lubrication. - The
canister 400 includes a thincylindrical portion 422 having an inner surface that is slightly larger than the outer surface of theinner magnet assembly 600, and having an outer surface that is slightly smaller than the inner surface of theimpeller magnet sleeve 712. Thecasing 100,backplate 200,canister 400 andnose cap 500 all remain stationary, are sealingly connected, and together form a sealed chamber rearward of thecanister 400. - The
inner magnet segments 646 of theinner magnet assembly 600 are axially aligned with theimpeller magnet segments 710 of theouter magnet assembly 705. The alternating polarity of theinner magnet segments 646 creates an inner magnetic field, and the alternating polarity of theimpeller magnet segments 710 creates an outer magnetic field. These two magnetic fields synchronize together to provide a strong magnetic coupling torque between theinner magnet assembly 600 and theimpeller assembly 700, such that when themotor 6 is energized, it rotates themotor shaft 22, which rotates theinner magnet assembly 600, which in turn, rotates therotatable impeller assembly 700. - The
impeller 702 of therotatable impeller assembly 700 includes a plurality ofvanes 740 that terminate along one side of ashroud 746, which in this example is the front side of a rear shroud. The front side of theshroud 746 has asurface 754 and in this example theshroud 746 is at the rear of thevanes 740. Thecasing 100 includes adischarge collector cavity 108 that is fluidly connected to thecasing discharge port 102. The rotation of theimpeller vanes 740 causes a pumping action in the location of thevanes 740, which is considered herein to be apumping cavity 750, and moves fluid into the pump through thecasing inlet port 104, radially outward through aprimary passage 752 to thedischarge collector cavity 108, and out of the pump through thedischarge port 102. - In this
first example pump 2, theshroud 746 separates thepumping cavity 750 from and defines with thecasing 100 arear cavity 110. Therear cavity 110 is partially blocked from thedischarge collector cavity 108 by theimpeller shroud 746. Thecasing 100 includes at least oneauxiliary passage 112 that connects thedischarge collector cavity 108 and therear cavity 110. In this example, there are threeauxiliary passages 112 spaced apart equally around thedischarge collector cavity 108. In essence, while theprimary passage 752 between the pumpingcavity 750 and thecollector discharge cavity 108 has a selected width, theauxiliary passage 112 expands the width of theprimary passage 752 at the location of theauxiliary passage 112. - It will be appreciated that the rotatable impeller assembly could include a front shroud, a rear shroud, or both a front and rear shroud. Moreover, as is shown with the
shroud 746, the at least one shroud has asurface 754 on the side along which thevanes 740 of therotatable impeller assembly 700 terminate, and thesurface 754 of theshroud 746 is substantially aligned with asurface 756 that defines theprimary passage 752 between the pumpingcavity 750 and thedischarge collector cavity 108. For pumping efficiency, theprimary passage 752 has a width at its inner end and the rotatableimpeller assembly vanes 740 have outer ends sized to span a distance D that substantially aligns the outer end of thevanes 740 with the width at the inner end of theprimary passage 752. It will be appreciated that the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from theshroud 746 andvanes 740 to theprimary passage 752. - During pump operation, rotation of the
rotatable impeller assembly 700 causes rotation of the fluid within therear cavity 110, which imparts centrifugal force on any solid particles that may be within the fluid in therear cavity 110, and causes the solid particles to move from the casingrear cavity 110 radially outward to and through the at least oneauxiliary passage 112 to thedischarge collector cavity 108. A casing having at least one suchauxiliary passage 112 helps to resist clogging of thepump 2 by avoiding the accumulation of solid particles in therear cavity 110 behind theshroud 746 of therotatable impeller assembly 700. This allows the solid particles to escape to thedischarge collector cavity 108, in this first example, through threeauxiliary passages 112, while maintaining most or all of the efficiency advantage of aprimary passage 752 being properly sized relative to the outer ends of thevanes 740 of theimpeller 702. In the example shown, therotatable impeller assembly 700 also may include at least one auxiliary vane located on theshroud 746 and within therear cavity 110, which would further enhance the centrifugal force applied by the rotation of therotatable impeller assembly 700 and assist in imparting centrifugal force on the solid particles within the fluid in therear cavity 110. - While
pump 2 is operating, the pumping action of theimpeller vanes 740 creates a pressure differential within thepump 2, such that the pressure or suction within theinlet port 104 in front of thenose cap 500 is lower than the discharge pressure in thedischarge collector cavity 108 and theoutlet port 102. Fluid in thepump 2 moves radially inward within therear cavity 110 due to the differential pressure in the fluid between suction at thepump inlet port 104 and discharge pressure at thepump outlet port 102. The movement of the fluid radially inward in therear cavity 110 may help provide fluid for a recirculation passageway behind therotatable impeller assembly 700 that begins at thedischarge collector cavity 108, where the pressure is high, extends between stationary and rotating surfaces, and ends in front of thenose cap 500 at theinlet port 104, where the pressure is low. The passageway is dynamic, since every part is bounded by a combination of stationary surfaces and rotating surfaces. The stationary surfaces are on thecasing 100,backplate 200,canister 400,rear thrust washer 814, bearingsleeve 806,front thrust washer 818 andnose cap 500. The rotating surfaces are on therotatable impeller assembly 700. - Turning to
FIGS. 6 and 7 , a second example pump 2 a is shown. The second example pump 2 a is similar to thefirst example pump 2 in many ways and essentially uses the drive, sealing, rotatable impeller assembly, and other rear structures of thefirst example pump 2, but differs in that it includes analternative pump casing 100 a, which is shown in a perspective sectioned view inFIG. 6 and in a side sectioned view inFIG. 7 . Given the similarity between the majority of the components of the first and second example pumps, to avoid redundancy and unnecessary length, this description and the accompanying drawings, focus on the most relevant differences between the examples. For instance, instead of having at least oneauxiliary passage 112 in the form of a groove, slot or channel that is open, connected to and effectively expands the width of aprimary passage 752 at the location of theauxiliary passage 112, this alternative second example configuration includes at least oneauxiliary passage 112 a in the form of a separate aperture. More particularly, the second example would have threeauxiliary passages 112 a in the form of separate apertures that are spaced equally around thedischarge collecting cavity 108 and that connect arear cavity 110 to thecollector discharge cavity 108. - The
rotatable impeller assembly 700 still has animpeller 702 having a plurality ofvanes 740. Thevanes 740 terminate at a side of ashroud 746 that has asurface 754. For pumping efficiency, theprimary passage 752 has a width at its inner end and thevanes 740 of therotatable impeller assembly 700 have outer ends sized to span a distance D that substantially aligns the outer end of thevanes 740 with the width at the inner end of theprimary passage 752. As with the first example, it will be appreciated that the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from theshroud 746 andvanes 740 to theprimary passage 752. Accordingly, thesurface 754 of theshroud 746 is substantially aligned with asurface 756 that defines theprimary passage 752 between the pumping cavity and thedischarge collector cavity 108. Thus, the main difference between the configuration and components of the second example pump 2 a relative to thefirst example pump 2 is the inclusion of at least one auxiliary passage in the form of anaperture 112 a, instead of at least one auxiliary passage in the form of aslot 112. However, theauxiliary passages 112 a in the form of apertures also would serve to resist pump clogging by allowing solid particles to pass from therear cavity 110 to thecollector discharge cavity 108. - Turning to
FIGS. 8 and 9 , athird example pump 2 b is shown. Thethird example pump 2 b is similar to thefirst example pump 2 in many ways and essentially uses the drive, sealing, rotatable impeller assembly, and other rear structures of thefirst example pump 2, but differs in that it includes analternative pump casing 100 b, which is shown in a perspective sectioned view inFIG. 8 and in a front sectioned view inFIG. 9 . Given the similarity between the majority of the components of the first and third example pumps, to avoid redundancy and unnecessary length, this description and the accompanying drawings, focus on the most relevant differences between the examples. For instance, instead of having at least oneauxiliary passage 112 in the form of a groove, slot or channel that is open, extends radially outward, and is connected to and effectively expands the width of aprimary passage 752 at the location of theauxiliary passage 112, this alternative third example configuration includes at least oneauxiliary passage 112 b in the form of a similar groove, slot or channel, but extending tangentially outward, while being connected to and effectively expanding the width of theprimary passage 752 at the location of theauxiliary passage 112 b. More particularly, the third example would have threeauxiliary passages 112 b in the form of separate tangentially extending slots that are spaced equally around thedischarge collecting cavity 108 and that connect arear cavity 110 to thecollector discharge cavity 108. - The
rotatable impeller assembly 700 still has animpeller 702 having a plurality ofvanes 740. Thevanes 740 terminate at a side of ashroud 746 that has asurface 754. For pumping efficiency, theprimary passage 752 has a width at its inner end and thevanes 740 of therotatable impeller assembly 700 have outer ends sized to span a distance D that substantially aligns the outer end of thevanes 740 with the width at the inner end of theprimary passage 752. As with the first example, it will be appreciated that the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from theshroud 746 andvanes 740 to theprimary passage 752. Accordingly, thesurface 754 of theshroud 746 is substantially aligned with asurface 756 that defines theprimary passage 752 between the pumping cavity and thedischarge collector cavity 108. Thus, the main difference between the configuration and components of thethird example pump 2 b relative to thefirst example pump 2 is the inclusion of at least one auxiliary passage in the form of aslot 112 b that extends tangentially, instead of at least one auxiliary passage in the form of aslot 112 that extends more directly radially. However, theauxiliary passages 112 b extending tangentially also would serve to resist pump clogging by allowing solid particles to pass from therear cavity 110 to thecollector discharge cavity 108, and while radial and tangential angles have been shown, it will be appreciated that the auxiliary passages could extend outward at any angle. - Turning to
FIGS. 10-12 , afourth example pump 2 c is shown, which is similar in many ways to thefirst example pump 2 and essentially uses the drive, sealing and other rear structures of thefirst example pump 2. Given the similarity between many of the components of the first and fourth example pumps, to avoid redundancy and unnecessary length, this description and the accompanying drawings, focus on the most relevant differences between the examples. For instance, thefourth example pump 2 c differs in that it includes analternative casing 100 c and an alternativerotatable impeller assembly 700 c, having analternative impeller 702 c, and having arear shroud 746 and afront shroud 746 c, which are shown in an enlarged closer perspective view of a quarter-sectioned area of the fourth example pump inFIG. 10 , in a front perspective view of a front sectioned portion inFIG. 11 , and in a rear perspective view of the corresponding front sectioned portion of thefourth example pump 2 c. - The
fourth example pump 2 c includes at least oneauxiliary passage 112 that is similar to the at least oneauxiliary passage 112 of thefirst example pump 2 in that it is in the form of a groove, slot or channel, and extends radially outward, while being connected to and effectively expanding the width of theprimary passage 752 at the location of theauxiliary passage 112, so as to connect therear cavity 110 with thedischarge collector cavity 108. However, thefourth example pump 2 c also includes at least oneauxiliary passage 112 c that is somewhat similar to the at least oneauxiliary passage 112 in that it is in the form of a groove, slot or channel, and extends radially outward, but it is connected to and effectively expands the width of theprimary passage 752 at the location of theauxiliary passage 112 c, so as to connect afront cavity 110 c that is forward of theshroud 746 c′ with thedischarge collector cavity 108. More particularly, thefourth example pump 2 c would have threeauxiliary passages 112 in the form of radially extending slots that are spaced equally around thedischarge collecting cavity 108 and that connect arear cavity 110 to thecollector discharge cavity 108, while also having have threeauxiliary passages 112 c in the form of radially extending slots that are spaced equally around thedischarge collecting cavity 108 and that connect afront cavity 110 to thecollector discharge cavity 108. - The
alternative impeller 702 c of therotatable impeller assembly 700 c of thefourth example pump 2 c includes a plurality ofvanes 740 c having outer ends that extend between therear shroud 746 and thefront shroud 746 c. The outer ends of thevanes 740 c terminate at their rear at a front side of therear shroud 746 that has asurface 754, and terminate at their front at a rear side of thefront shroud 746 c that has asurface 754 c. Thecasing 100 c includes adischarge collector cavity 108 that is fluidly connected to thecasing discharge port 102. The rotation of theimpeller vanes 740 c causes a pumping action in the location of thevanes 740 c, which is considered herein to be a pumping cavity 750 c, and moves fluid into the pump through thecasing inlet port 104, radially outward through aprimary passage 752 to thedischarge collector cavity 108, and out of the pump through thedischarge port 102. - For pumping efficiency, the
primary passage 752 has a width at its inner end and thevanes 740 c of therotatable impeller assembly 700 c have outer ends sized to span a distance D that substantially aligns the outer end of thevanes 740 c with the width at the inner end of theprimary passage 752. As with the first example, it will be appreciated that the surfaces may be angled or other than directly radial, but will be aligned for a smooth transition from therear shroud 746 andfront shroud 746 c andvanes 740 c to theprimary passage 752. Accordingly, thesurface 754 of theshroud 746 is substantially aligned with asurface 756 that defines one side of theprimary passage 752 between the pumping cavity and thedischarge collector cavity 108, withsurface 754 c of theshroud 746 c similarly being substantially aligned with asurface 756 c that defines the other side of theprimary passage 752. Thus, the main differences between the configuration and components of thefourth example pump 2 c relative to thefirst example pump 2 is the inclusion of at least arear shroud 746 and afront shroud 746 c, which define with thecasing 100 c arear cavity 110 rearward of therear shroud 746 and afront cavity 110 c forward of thefront shroud 746 c, and the respective inclusion of at least oneauxiliary passage 112 in the form of a slot that extends radially and connects therear cavity 110 with thedischarge collector cavity 108, as well as at least oneauxiliary passage 112 c in the form of a slot that extends radially and connects thefront cavity 110 c with thedischarge collector cavity 108. Theauxiliary passages rear cavity 110 andfront cavity 110 c to thecollector discharge cavity 108. - From the above disclosure, it will be apparent that pumps constructed in accordance with this disclosure may include a number of structural aspects that provide advantages over conventional constructions, depending upon the specific design chosen.
- It will be appreciated that a pump constructed in accordance with the present disclosure may be provided in various configurations. Any variety of suitable materials of construction, configurations, shapes and sizes for the components and methods of connecting the components may be utilized to meet the particular needs and requirements of an end user. Indeed, pumps in accordance with the present disclosure may include interior surfaces that are constructed of specific materials and/or have particular surface finishes wherein the interior surfaces permit use of the pumps in hygienic applications where microbial growth must be prevented. It will be apparent to those skilled in the art that various modifications can be made in the design and construction of such pumps without departing from the scope or spirit of the claimed subject matter, and that the claims are not limited to the preferred embodiment illustrated herein. It also will be appreciated that some aspects of the example embodiment are discussed in a simplified manner, as the invention is capable of being implemented in rotodynamic pumps, whether such pumps include dynamic seals between rotating parts or are magnetically driven.
Claims (10)
1. A rotodynamic pump that resists clogging when pumping fluid that contains solid particles having a density that is greater than the fluid, comprising:
a stationary casing having a front portion, a rear portion, an inlet port, an outlet port, a pumping cavity, and a discharge collector cavity located radially outward from the pumping cavity and in fluid communication with the outlet;
a rotatable impeller assembly comprising vanes that terminate along a side of at least one of a front shroud or a rear shroud, wherein the at least one of the front shroud or rear shroud separates the pumping cavity from and defines with the casing at least one respective front cavity or rear cavity;
the stationary casing further comprising a primary passage between the pumping cavity and the discharge collector cavity, and at least one auxiliary passage connecting the discharge collector cavity and the at least one front cavity or rear cavity; and
wherein rotation of the rotatable impeller assembly imparts centrifugal force on solid particles within fluid in the at least one front cavity or rear cavity and causes the solid particles to move from the at least one front cavity or rear cavity radially outward to and through the at least one auxiliary passage to the discharge collector cavity.
2. The rotodynamic pump of claim 1 , wherein the primary passage has a width and the rotatable impeller assembly vanes have outer ends sized to span a distance substantially similar to the width of the primary passage.
3. The rotodynamic pump of claim 1 , wherein the at least one front shroud or rear shroud has a surface on the side along which the vanes of the rotatable impeller assembly terminate, and wherein the surface is substantially aligned with a surface defining the primary passage between the pumping cavity and the discharge collector cavity.
4. The rotodynamic pump of claim 1 , wherein the rotatable impeller assembly further comprises at least one auxiliary vane located on the at least one front shroud or rear shroud and within the respective at least one front cavity or rear cavity; and
wherein the at least one auxiliary vane located on the at least one front shroud or rear shroud assists in imparting centrifugal force on solid particles within the fluid.
5. The rotodynamic pump of claim 1 , wherein fluid moves radially inward within the at least one front cavity or rear cavity due to differential pressure in the fluid between suction at the pump inlet port and discharge pressure at the pump outlet port.
6. The rotodynamic pump of claim 1 , wherein the primary passage has a width and the at least one auxiliary passage is connected to and expands the width of the primary passage at the auxiliary passage.
7. The rotodynamic pump of claim 1 , wherein the auxiliary passage extends radially outward.
8. The rotodynamic pump of claim 1 , wherein the auxiliary passage extends tangentially outward.
9. The rotodynamic pump of claim 1 , wherein the at least one auxiliary passage is separate from the primary passage.
10. The rotodynamic pump of claim 1 , wherein the rotatable impeller assembly is magnetically driven.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/277,795 US20170175757A1 (en) | 2015-09-30 | 2016-09-27 | Rotodynamic Pumps that Resist Clogging |
PCT/US2016/054209 WO2017058935A1 (en) | 2015-09-30 | 2016-09-28 | Rotodynamic pumps that resist clogging |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201562235255P | 2015-09-30 | 2015-09-30 | |
US15/277,795 US20170175757A1 (en) | 2015-09-30 | 2016-09-27 | Rotodynamic Pumps that Resist Clogging |
Publications (1)
Publication Number | Publication Date |
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US20170175757A1 true US20170175757A1 (en) | 2017-06-22 |
Family
ID=58427872
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/277,795 Abandoned US20170175757A1 (en) | 2015-09-30 | 2016-09-27 | Rotodynamic Pumps that Resist Clogging |
Country Status (2)
Country | Link |
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US (1) | US20170175757A1 (en) |
WO (1) | WO2017058935A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10712183B2 (en) * | 2016-03-09 | 2020-07-14 | Onesubsea Ip Uk Limited | Determining flow rates of multiphase fluids |
US10738782B2 (en) * | 2016-11-01 | 2020-08-11 | Psg Worldwide, Inc. | Magnetically coupled sealless centrifugal pump |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2588323B1 (en) * | 1985-10-09 | 1990-02-23 | Ngk Insulators Ltd | MAGNETICALLY DRIVEN CENTRIFUGAL PUMP |
EP0298191B1 (en) * | 1987-07-06 | 1992-05-20 | Rockwell International Corporation | Multiple discharge cylindrical pump collector |
US6099243A (en) * | 1999-01-29 | 2000-08-08 | Caterpillar Inc. | Centrifugal pump with seal cooling and debris flushing arrangement |
JP2005282518A (en) * | 2004-03-30 | 2005-10-13 | Aisin Seiki Co Ltd | Centrifugal pump with foreign substance collecting function |
-
2016
- 2016-09-27 US US15/277,795 patent/US20170175757A1/en not_active Abandoned
- 2016-09-28 WO PCT/US2016/054209 patent/WO2017058935A1/en active Application Filing
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10712183B2 (en) * | 2016-03-09 | 2020-07-14 | Onesubsea Ip Uk Limited | Determining flow rates of multiphase fluids |
US10738782B2 (en) * | 2016-11-01 | 2020-08-11 | Psg Worldwide, Inc. | Magnetically coupled sealless centrifugal pump |
US11396890B2 (en) | 2016-11-01 | 2022-07-26 | Psg California Llc | Magnetically coupled sealless centrifugal pump |
Also Published As
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WO2017058935A1 (en) | 2017-04-06 |
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