US20070077155A1 - Centrifugal pump with hydrodynamic bearing and double involute - Google Patents

Abstract

A centrifugal pump with a hydrodynamic bearing and a double involute is disclosed. Some embodiments may include an impeller housing comprising a fluid entrance to allow fluid to enter and an impeller located within the impeller housing, the impeller comprising a plurality of impeller blades, a plurality of fluid channels between the impeller blades, and a motor magnet. The impeller may rotate within the impeller housing about a pump centerline in response to an electromagnetic field and the fluid channels may each allow fluid to pass through when the impeller rotates. Embodiments may also include one or more hydrodynamic bearings positioned between the impeller and the impeller housing to support generated loads and a double involute coupled with the impeller housing and positioned to receive fluid exiting the plurality of fluid channels. Further embodiments may include a motor stator to generate the electromagnetic field. Other embodiments are disclosed and claimed.

Description

FIELD
• The present invention is in the field of centrifugal pumps. More particularly, the present invention relates to a centrifugal pump with a hydrodynamic bearing and a double involute.
BACKGROUND
• Electronic devices generate heat during operation. Device designers often utilize thermal management to keep temperature-sensitive elements of an electronic device within a prescribed operating temperature. Failure to properly cool an electronic device can result in overheating, which may cause a reduction in device service life, device failure, or a reduction in operating performance. Historically, designers have cooled electronic devices using natural convection by strategically locating openings in the device packaging or case to allowed warm air to escape and cooler air to be drawn in. The advent of high performance electronic devices such as processors, however, now requires more sophisticated thermal management. Increasing electronic device performance often results in an increase in the heat generated by the device and often results in a smaller size for the electronic device, both conditions of which increase the amount of thermal energy that needs to be handled. As electronic device designs continue to increase in sophistication, these problems will be exacerbated and the need for improved thermal management will continue to increase.
• One thermal management solution for high performance processors or other computer system components is the use of liquid cooling. One method of liquid cooling of components is to use a cold plate thermally coupled to the component. In this solution, a pump may pump cooling fluid through the cold plate, allowing heat to be transferred from the component to the cooling fluid through the cold plate, after which the heat is removed from the cooling fluid via a heat exchanger and then returned to the cold plate. Liquid cooling using a cold plate can be more effective than solid conduction cooling methods and can also provide additional flexibility in the size and location of the heat exchanger, as the system can pump the heated fluid to a heat exchanger located in a more desirable location. While a liquid cooling system can be effective at cooling high performance components, it can be more expensive and complicated than previous methods. Because of the cost and complexity of liquid cooling systems, liquid cooling is typically only used on higher end systems. The cost and complexity of pumps to move cooling fluid through a liquid cooling system is a significant part of the cost and complexity of the entire liquid cooling system. Reducing the cost and complexity of liquid cooling pumps can therefore make liquid cooling solutions for heat-generating components suitable for more systems.
BRIEF DESCRIPTION OF THE DRAWINGS
• Advantages of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings in which like references may indicate similar elements:
• FIG. 1 depicts a side cut-away view of a centrifugal pump with a double involute and hydrodynamic bearings according to one embodiment;
• FIG. 2 depicts a side cut-away view of a hydrodynamic thrust bearing of the centrifugal pump ofFIG. 1 according to one embodiment;
• FIG. 3 depicts a cut-away plan view of a double involute of the centrifugal pump ofFIG. 1 according to one embodiment; and
• FIG. 4 depicts a flowchart of an embodiment to pump cooling fluid in a cooling system.
DETAILED DESCRIPTION OF EMBODIMENTS
• The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The example embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The detailed descriptions below are designed to make such embodiments obvious to a person of ordinary skill in the art.
• Generally speaking, a centrifugal pump with a hydrodynamic bearing and a double involute is disclosed. Some embodiments may include an impeller housing comprising a fluid entrance to allow fluid to enter and an impeller located within the impeller housing, the impeller comprising a plurality of impeller blades, a plurality of fluid channels between the impeller blades, and a motor magnet. The impeller may rotate within the impeller housing about a pump centerline in response to an electromagnetic field and the fluid channels may each allow fluid to pass through when the impeller rotates. Embodiments may also include one or more hydrodynamic bearings positioned between the impeller and the impeller housing to support generated loads and a double involute coupled with the impeller housing and positioned to receive fluid exiting the plurality of fluid channels. Further embodiments may include a motor stator to generate the electromagnetic field.
• Another embodiment comprises a method for pumping cooling fluid. Some embodiments of the method may include receiving a cooling fluid into an impeller and driving the impeller to rotate about an axis to force the cooling fluid to exit the impeller. Embodiments may also include receiving the exiting cooling fluid at two or more involutes and increasing a static pressure of the cooling fluid in the two or more involutes. Embodiments may also include reacting any loads generated by the two or more involutes and rotating impeller with one or more hydrodynamic bearings. Further embodiments may include after increasing the static pressure of the cooling fluid, passing the cooling fluid to a cooling system.
• The disclosed system and methodology may advantageously provide for a centrifugal pump with two or more involutes, such as a double involute, and hydrodynamic bearings. The use of a two or more involutes may reduce radial and moment loads on the impeller and centrifugal pump and may thus allow for the use of hydrodynamic bearings instead of solid element bearing technologies, potentially reducing the cost and complexity of the centrifugal pump. The combination of a multiple involutes with hydrodynamic bearings may also allow for the use of plastic injection molded parts for the centrifugal pump, potentially further reducing the cost of the pump. Reduced cost and complexity for centrifugal pumps may allow for use of centrifugal pumps and liquid cooling in a more diverse set of circumstances and for more types of systems.
• Various embodiments of the present invention provide systems and methods for pumping fluid. The following description provides specific details of certain embodiments of the invention illustrated in the drawings to provide a thorough understanding of those embodiments. It should be recognized, however, that the present invention can be reflected in additional embodiments and may be practiced without some of the details in the following description. In other instances, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the invention. While specific embodiments will be described below with reference to particular configurations and systems, those of skill in the art will realize that embodiments of the present invention may advantageously be implemented with other substantially equivalent configurations and/or systems.
• Turning now to the drawings,FIG. 1 depicts a side cut-away view of a centrifugal pump with a double involute and hydrodynamic bearings according to one embodiment. The centrifugal pump100 ofFIG. 1 includes animpeller106 having amotor magnet108 housed within animpeller housing102. Amotor stator104 may be located in or outside theimpeller housing102. When electric power is applied to themotor stator104, themotor stator104 creates a magnetic field that may drive themotor magnet108 of theimpeller106, causing theimpeller106 to rotate within theimpeller housing102 and about apump centerline110. Cooling fluid may enter theimpeller housing102 through, for example, afluid entrance126. As the axial flow input enters theimpeller housing102 through the fluid entrance (and along the pump centerline110), it flows into the rotatingimpeller106. The rotational speed of theimpeller106 creates a centrifugal force that propels the fluid throughfluid channels114 formed by and between a plurality ofimpeller blades112. The fluid exiting thefluid channels114 may be collected by adouble involute132 at twoinvolute tongues130. The double involute132 (as described in more detail in relation toFIG. 3) may then convert the dynamic pressure of the fluid to a static pressure, generating the pressure difference used by the centrifugal pump100 to drive the cooling fluid. Thedouble involute132 may generate equal and opposite loads at each involute which cancel out to create a relatively small net radial load. With adouble involute132, the generated loads are equal and opposite when theimpeller106 has an even number ofimpeller blades112 evenly distributed around theimpeller106 and hence animpeller blade112 passes both involutetongues130 at the same time. Adouble involute132 may thus provide a more balanced and lower radial load on the bearings of the centrifugal pump100 when compared to a single involute.
• The centrifugal pump100 of the disclosed embodiments may utilize hydrodynamic bearings between theimpeller106 andimpeller housing102 to support the rotatingimpeller106 and its associated loads within theimpeller housing102. Hydrodynamic bearings (which are described in more detail in relation toFIG. 2) may rely on the gap between a stationary surface (i.e., the inside surface of the impeller housing102) and a moving surface (i.e., the outside surface of the rotating impeller106) and viscous effects of its constituent bearing film to handle the net radial force and moment associated with the development of mass flow and static pressure on theimpeller blades112. The hydrodynamic bearings may include one ormore journal bearings122 positioned between theimpeller106 and theimpeller housing102, such as near themotor stator104, and one ormore thrust bearings124 positioned between theimpeller blades112 and theimpeller housing102. Hydrodynamic bearings may be less expensive than other types of bearings (such as roller bearings, ball bearings, needle bearings or other solid element bearings) but often have less load-bearing capacity than the more expensive bearings. The reduced loads resulting from thedouble involute132 may advantageously allow the use of hydrodynamic bearings in the centrifugal pump100 instead of more expensive and higher capacity bearings, providing for a less expensive centrifugal pump100.
• Theimpeller housing102 of the depicted embodiment is symmetrical about thepump centerline110, completely enclosing theimpeller106 while allowing the passage of fluid into theimpeller housing102 through thefluid entrance126. Thefluid entrance126 may be an opening (or multiple openings) in theimpeller housing102 or other component (such as a tube or pipe) that allows passage of cooling fluid into theimpeller housing102. Theimpeller housing102 may be made of any type of material, including metal or plastic, and may be of any shape adapted to partially or fully enclose theimpeller106. In one embodiment, theimpeller housing102 may be manufactured using plastic injected part manufacturing methods. Theimpeller housing102 may be oriented vertically (as depicted inFIG. 1) with a gravitational force oriented downward, horizontally with thepump centerline110 perpendicular to the gravitational force, or in any other direction. Theimpeller housing102 may be part of a larger system or may be coupled to other components, such as a cold plate for a liquid cooling system.
• Theimpeller106 may include animpeller body116 in addition to themotor magnet108. Similarly to theimpeller housing102, theimpeller body116 may be made of any type of material, including metal or plastic, and may be injection molded plastic in one embodiment. Themotor magnet108 may be attached to theimpeller body116 in any fashion such that a rotational force applied to themotor magnet108 also rotates the impeller body116 (and thus theimpeller106 as a whole). This allows theimpeller106 to be magnetically coupled with themotor stator104 through the wall of theimpeller housing102. This eliminates the need to have a shaft or other physical coupling mechanism to connect to drive theimpeller106. This may reduce cost and complexity, as a shaft through theimpeller housing102 to drive theimpeller106 would require, for example, rotating seals, which may be expensive and prone to leakage. In one embodiment, themotor stator104 is outside theimpeller housing102 and shaped as a concentric circle around the outside of theimpeller housing102. For example, themotor stator104 may be one or more laminated steel sheets with copper wires wound on it and wrapped around theimpeller housing106 that generates a magnetic field when a direct current (DC) charge is applied to the copper wire.Other motor stator104 designs may also be used, includingsolid motor stators104 or amotor stator104 that is partially or fully integrated within the wall of theimpeller housing102.
• Theimpeller body116 andmotor magnet108 may be configured in any way. In one embodiment, for example, themotor magnet108 may be positioned outside of theimpeller body116 so that themotor magnet108 is closer to themotor stator104. This embodiment may maximize the magnetic force created by themotor magnet108 andmotor stator104 as themotor magnet108 will be closer to themotor stator104 and thus in a more powerful part of the motor stator's104 magnetic field when it is powered. In another embodiment, themotor magnet108 may be positioned on the inside of theimpeller body116 so that it is closer to thepump centerline110. In other embodiments, theimpeller body116 may fully or partially enclose themotor magnet108. In an alternative embodiment, themotor magnet108 may serve as theimpeller body116, eliminating the need for aseparate motor magnet108 andimpeller body116.
• As described previously, the rotational speed of theimpeller106 creates a centrifugal force that propels cooling fluid through thefluid channels114 between the plurality ofimpeller blades112 of theimpeller106. Theimpeller blades112, which may be part of theimpeller106, may be any shape or size. Likewise, thefluid channels114 formed between theimpeller blades112 to allow passage of cooling fluid through their length may be any size or shape suitable to allow passage of cooling fluid. The centrifugal force created when theimpeller106 pushes cooling fluid through thefluid channels114 from the inside of theimpeller blade112 towards theimpeller housing102 to the outside of theimpeller blade112.
• The cooling fluid exiting thefluid channels114 of theimpeller blades112 may be collected by an involute. An involute may be any geometry that collects fluid exiting theimpeller blades112 and efficiently increases the static pressure of the fluid before it exits the involute. The involute may accomplish the increased static pressure by converting the dynamic pressure resulting from the circumferential velocity of the fluid and converting it to static pressure of the cooling fluid. The involute may advantageously be adouble involute132 having twoinvolute channels134 over at least part of its length. Thedouble involute132 may be positioned on the exterior of theimpeller housing102 and wrapped around the circumference of theimpeller housing102. Thedouble involute132 may have two involute tongues130 (which may also be known as cutwaters). Theinvolute tongue130 may represent the closest point of thedouble involute132 to thefluid channel exit114 and as such is the point where thedouble involute132 interacts with the cooling fluid exiting theimpeller106.
• The conversion of the velocity of the cooling fluid to an increase in static pressure of the fluid in the involute132 may result in a reactionary force on theimpeller106. Due to the close proximity of theinvolute tongue130 to theimpeller blades112, theinvolute tongue130 may generate a reaction force on theimpeller blades112, thus creating a radial and tangential reaction force in theimpeller106 itself. The tangential reaction force may be overcome with the torque capability of the motor (the combinedmotor stator104 and motor magnet108). The net radial load (both its magnitude and direction) may result from the integration of the radial reaction forces generated by thedouble involute132 over its entire circumference of 360 degrees. By employing twoinvolute channels134 andinvolute tongues130 that are approximately 180 degrees apart, thedouble involute132 may substantially balance the impeller loading, resulting in smaller net radial loads when compared to single involute designs. To accomplish this, thedouble involute132 may generate equal and opposite loads at each involute which cancel out to create a relatively small net radial load. To help maintain a low net radial load, theimpeller106 may have an even number ofimpeller blades112 evenly distributed around theimpeller106, resulting in animpeller blade112 passing bothinvolute tongues130 simultaneously and resulting in generated loads that are equal and opposite. Single involute designs may result in such high radial loads that hydrodynamic bearings are not viable and more expensive mechanical bearing approaches must be employed. Adouble involute132 may thus provide a more balanced and lower net radial load on the bearings of the centrifugal pump100 when compared to a single involute.
• In an alternative embodiment, the centrifugal pump100 may have more than two involutes instead of adouble involute132. In this embodiment, the number ofimpeller blades112 may be matched to the number of involutes to balance the net radial loads. A three involute centrifugal pump100, for example, may have a plurality ofimpeller blades112 in a multiple of three (e.g., 3, 6, 9, 30, etc.) in order to substantially balance the loads. Similarly, a five involute centrifugal pump100 may haveimpeller blades112 in multiples of five (e.g., 5, 10, etc.) to properly balance the loads. A centrifugal pump100 with an even number of involutes (e.g., 2, 4, 6, etc.) may have an even number ofimpeller blades112 to provide load balancing. A centrifugal pump100 with the number of involutes and the number ofimpeller blades112 matched to achieve load balancing may have significantly less net radial loads than a single involute design, regardless of the number ofimpeller blades112. While a double involute centrifugal pump100 is depicted in the Figures and described herein, one skilled in the art will recognize that other multiple involute designs may also be used.
• Hydrodynamic bearings such as the journal bearing122 and thrustbearing124 may support the loads generated by the operation of the centrifugal pump100. The journal bearing122 may support therotating impeller106 andmotor magnet108 and a combination of the journal bearing122 and thrustbearing124 may support the net radial load and force moment associated with the development of mass flow and static pressure on theimpeller blades112. Thethrust bearing124 may also help balance component gravity loads (depending on the orientation of the centrifugal pump100) as well as support the moment loads generated by the offset between the journal bearing122 surface and theimpeller106 height difference (where radial load is generated). The journal bearing122 may be created or positioned in the gap between themotor magnet108 and/orimpeller body116 and theimpeller housing102 in the region near the motor stator104 (or the surface of themotor stator104 itself). The journal bearing122 may include a hydrodynamic fluid located in the gap between the rotating cylinder (the impeller106) and the stationary cylinder (themotor stator104 or impeller housing102). The journal bearing122 may be created or positioned either on the outside of the rotating cylinder, the inside of the rotating cylinder, or both. Thethrust bearing124, on the other hand, may be created or positioned in the gap between the bottom of the impeller106 (e.g., the disk surface of the impeller106) and theimpeller housing102 and/or the gap between the top of theimpeller blades112 and theimpeller housing102.
• Thejournal bearings122 and thrustbearings124 are hydrodynamic in nature and their performance may typically be dominated by the viscous effects between the stationary (i.e., the impeller housing102) and moving surfaces (i.e., the impeller106). The effectiveness of the hydrodynamic lubrication may be closely coupled to surface geometry and interfaces (i.e., gaps between surfaces). The effectiveness and load capability of the journal bearing122, for example, may be related to the eccentricity of the inner cylinder (i.e., the shape of the impeller106), the viscosity of the fluid in the gap, the speed of therotating impeller106, the radius of the inner cylinder, and the radial clearance between the two cylinders (i.e., the gap), or other factors. For example, a reduction in the gap of the journal bearing122 may improve the bearing performance. A gap reduction may also improve the efficiency of the motor by bringing themotor magnet108 andmotor stator104 closer together and increasing the strength of the generated magnetic field on themotor magnet108 and reducing the unused field, or magnetic leakage, between the two components. Improved motor efficiency may allow for less complicated control circuitry or less windings. Reduction of the gap, on the other hand, may also increase the torque losses in the motor due to the increase in shear losses in the fluid, and an optimal gap may exist based on balancing the different factors and the particular configuration.Thrust bearings124 are impacted by similar factors asjournal bearings122, such as by the geometry of the bearing surfaces, the speed of rotation, etc.
• FIG. 2 depicts a side cut-away view of a hydrodynamic thrust bearing of the centrifugal pump ofFIG. 1 according to one embodiment. InFIG. 2, thethrust bearing124 is positioned between a housinginner surface206 of theimpeller housing102 and a thrust bearing surface204 of theimpeller body116 part of theimpeller blade112. The distance between theimpeller body116 and theimpeller housing102 that forms thethrust bearing124 is thethrust bearing gap202. As described in relation toFIG. 1, afluid channel114 may be positioned on the opposite side of theimpeller body116 from thethrust bearing124. WhileFIG. 2 is described as athrust bearing124 herein, the description ofFIG. 2 is equally applicable to a journal bearing122 with, for example, amotor magnet108 replacing theimpeller blade112 orimpeller body116 in the description.
• As described previously, the size of thethrust bearing gap202 may impact the performance of thethrust bearing124. A smallerthrust bearing gap202 may result in improved load capacity of thethrust bearing124 while largerthrust bearing gaps202 may result in reduced capacity. In one embodiment, the geometry and tolerances associated with the bearing surfaces (thrust bearing surface204 and housing inner surface206) may be such that thethrust bearing gap202 does not grow so large that thethrust bearing124 cannot support the required loads. Tighter manufacturing tolerances of the housinginner surface206 and thrust bearing surface204, as examples, and reduced size of thethrust bearing gap202 may therefore provide for more consistent and predictable load bearing capability as well as increased capability. Close manufacturing tolerances may also prevent gross instabilities in the position of theimpeller106 and therefore load fluctuations on theimpeller106, as the loading on theimpeller blades112 may be dependent on their distance in interaction with thedouble involute132 geometry.
• In one embodiment, a journal bearing122 may be constructed with less expensive materials while still maintaining sufficiently close tolerances. The close tolerances may include both dimensional geometric aspects of the journal bearing122 cylinders (i.e., diameters and eccentricity of the hole and cylinder). Close tolerances may be achieved using cost-effective plastic injected part manufacturing by providing support to the resulting thermoplastic walls by using components that act as a stabilizing backbone. For example, the journal bearing thermoplastic surface (equivalent to the housinginner surface206 of the thrust bearing124) may be stabilized by ametal motor stator104. Similarly, the journal surface (equivalent to the thrust bearing surface204 of the thrust bearing124) may be stabilized with themotor magnet108 ring. The composite construction may allow for more stable dimensional control and less geometric departure than simple plastic injection molded surfaces.
• FIG. 3 depicts a cut-away plan view of a double involute of the centrifugal pump ofFIG. 1 according to one embodiment. In the embodiment ofFIG. 3, the centrifugal pump100 includes adouble involute132 around animpeller106 that is adapted to rotate clockwise (inFIG. 3) about acenterline110. Theimpeller106 may include a plurality ofimpeller blades112 withfluid channels114 to transport cooling fluid from theimpeller106 to thedouble involute132 at a high velocity. The walls of theimpeller blades112 depicted inFIG. 3 are shown with no thickness for purposes of clarity. Thedouble involute132 may collect the high velocity fluid exiting thefluid channels114 and may efficiently increase the static pressure of the fluid by the geometry of thedouble involute132, resulting in a higher pressure fluid for use in a cooling system.
• Thedouble involute132 of the disclosed embodiments includes twoinvolute channels134 each beginning at aninvolute tongue130 and ending at aninvolute throat302. Fluid may enter eachinvolute channel134 at theinvolute tongue130 and travel the length of theinvolute channel134 between its walls until exiting thedouble involute132 at theinvolute throat302. Theinvolute tongues130 are the start of the involute geometry and may represent the closest point that the involute wall interacts with the fluid exiting theimpeller106. Theinvolute throat302 may be of any length or configuration and may fluidly connect to a cooling system. Due to its close proximity, theinvolute tongue130 generates the largest reaction force on theimpeller blades112, thus creating a radial and tangential reaction force in theimpeller106 itself. This tangential force may be overcome with the motor's torque capability. The integration of the radial reaction forces generated by the involute walls over their entire length generates the net radial load, including both its magnitude and direction.
• The design of thedouble involute132 helps reduce net radial loads in comparison to single involute designs. In the depicteddouble involute132 design, the two involute tongues130 (labeled ‘A’ and ‘B’ inFIG. 3) are positioned opposite each other and approximately 180 degrees apart. This may substantially balance theimpeller106 loading and results in a relatively small net radial load. Theoutside involute channel134, which begins at involute tongue130 ‘A’, may receive fluid exitingimpeller blades112 positioned between involute tongue130 ‘A’ clockwise to involute tongue130 ‘B’ (from approximately the 9 o'clock position to approximately the 3 o'clock position). The fluid gathered by the outerinvolute channel134 then travels around the channel until it exits at theinvolute throat302, giving it approximately 180 degrees of travel within the outerinvolute channel134. The innerinvolute channel134, which begins at involute tongue130 ‘B’, may receive fluid exitingimpeller blades112 positioned between involute tongue130 ‘B’ clockwise to involute tongue130 ‘A’ (from approximately the 3 o'clock position to approximately the 9 o'clock position). The fluid gathered by the innerinvolute channel134 travels around the channel until it exits at theinvolute throat302, giving it up to 180 degrees of travel within the innerinvolute channel134. By employing twoinvolute channels134 and associated geometry that are approximately 180 degrees apart theimpeller106 loading may advantageously be directly balanced and the net radial load reduced when compared to single involute designs. Positioning of theinvolute tongues130 in separate halves of thedouble involute132 may be considered positioning theinvolute tongues130 opposite of each other. While the twoinvolute tongues130 are described as being approximately 180 degrees apart, they may be positioned such that they are not directly opposite. For a typical geometry, the closer the twoinvolute tongues130 are to directly opposite each other, however, the more the net radial load is reduced.
• The geometry of the components of thedouble involute132 may impact its performance. For example, changes to the length and shape of theinvolute channels134, including the area growth of the channel, may cause changes in the pressure gain in thedouble involute132 as well as the loads during operation. Similarly, changes to the final area output and shape of theinvolute throat302 may result in changes in the pressure gain of thedouble involute132. Thedouble involute132 may in some embodiments have a configuration designed to optimize pressure gain, minimize net radial loads, or a combination of these or any other factors.
• FIG. 4 depicts a flowchart of an embodiment to pump cooling fluid in a cooling system. In one embodiment, one or more components of a centrifugal pump100 may perform the elements offlowchart400. In the depicted embodiment,flowchart400 begins withelement402, receiving cooling fluid into animpeller106, such as through thefluid entrance126 of theimpeller housing102.Flowchart400 may then continue toelement404, where the centrifugal pump100 drives theimpeller106 to rotate about an axis, such as thepump centerline110. The centrifugal pump100 may drive theimpeller106 by, in one embodiment, providing an electric charge to themotor stator104, which in turn drives themotor magnet108 of theimpeller106. Atelement406, the centrifugal forces generated by the rotatingimpeller106 may then force the cooling fluid throughfluid channels114 of theimpeller blades112 to exit theimpeller106.
• After the cooling fluid exits theimpeller106, two or more involutes (such as a double involute132) may receive the cooling fluid atelement408. In one embodiment, thedouble involute132 may receive the cooling fluid at twoinvolute tongues130. Thedouble involute132 may next, through its geometry, increase the static pressure of the cooling fluid atelement410 by converting the velocity and dynamic pressure of the cooling fluid into static pressure. Thedouble involute132 may accomplish this by passing the cooling fluid through theinvolute channels134 as the area of eachinvolute channel134 increases. Atelement412, any loads, such as a net radial load, generated by the involutes atelements408 or410 may be reacted by hydrodynamic bearings such as one ormore journal bearings122 and one ormore thrust bearings124. The involutes may then pass the cooling fluid back into the cooling system (at a higher static pressure), after which the method offlow chart400 terminates. While the elements offlow chart400 are shown sequentially, many of the elements may be performed simultaneously. Reacting the generated loads atelement412, for example, may be performed simultaneously and in response to increasing the static pressure of the cooling fluid atelement410.
• While certain operations have been described herein relative to a direction such as “above” or “below” it will be understood that the descriptors are relative and that they may be reversed or otherwise changed if the relevant structure(s) were inverted or moved. Therefore, these terms are not intended to be limiting.
• It will be apparent to those skilled in the art having the benefit of this disclosure that the present invention contemplates a centrifugal pump with a double involute and hydrodynamic bearings. It is understood that the form of the invention shown and described in the detailed description and the drawings are to be taken merely as examples. It is intended that the following claims be interpreted broadly to embrace all the variations of the example embodiments disclosed.
• Although the present invention and some of its advantages have been described in detail for some embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Although an embodiment of the invention may achieve multiple objectives, not every embodiment falling within the scope of the attached claims will achieve every objective. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims (29)

1. A centrifugal pump comprising:

an impeller housing, the impeller housing comprising a fluid entrance to allow fluid to enter the impeller housing;

an impeller located within the impeller housing comprising a plurality of impeller blades, a plurality of fluid channels between the impeller blades, and a motor magnet, wherein the impeller rotates within the impeller housing about a pump centerline in response to an electromagnetic field, and wherein further the fluid channels allow fluid to pass through when the impeller rotates;

one or more hydrodynamic bearings positioned between the impeller and the impeller housing to support generated loads; and

a double involute coupled with the impeller housing and positioned to receive fluid exiting the plurality of impeller blades.

2. The centrifugal pump ofclaim 1, further comprising a motor stator positioned at least partially outside the impeller housing to generate an electromagnetic field in response to an electrical charge.

3. The centrifugal pump ofclaim 1, further comprising a motor stator positioned at least partially within the impeller housing to generate an electromagnetic field in response to an electrical charge.

4. The centrifugal pump ofclaim 1, wherein the impeller housing is comprised of an injection molded plastic material.

5. The centrifugal pump ofclaim 1, wherein the impeller further comprises an impeller body coupled to the motor magnet.

6. The centrifugal pump ofclaim 5, wherein the impeller body is positioned between the pump centerline and the motor stator.

7. The centrifugal pump ofclaim 5, wherein the motor stator is positioned between the pump centerline and the impeller body.

8. The centrifugal pump ofclaim 1, wherein the impeller is at least partially comprised of an injection molded plastic material.

9. The centrifugal pump ofclaim 1, wherein the plurality of impeller blades are an even number of impeller blades.

10. The centrifugal pump ofclaim 1, wherein the plurality of impeller blades are substantially evenly distributed around the impeller.

11. The centrifugal pump ofclaim 1, wherein the one or more hydrodynamic bearings comprise a journal bearing positioned between the impeller housing and the impeller.

12. The centrifugal pump ofclaim 1, wherein the one or more hydrodynamic bearings comprise a thrust bearing positioned between the impeller housing and the impeller blades.

13. The centrifugal pump ofclaim 1, wherein the double involute further comprises:

two involute tongues to receive fluid from the fluid channels;

an involute throat to allow exit of fluid from the double involute; and

two involute channels to pass fluid from the involute tongues to the involute throat.

14. The centrifugal pump ofclaim 13, wherein the two involute tongues are positioned opposite each other.

15. A method for pumping cooling fluid, the method comprising:

receiving cooling fluid into an impeller;

driving the impeller to rotate about an axis to force the cooling fluid to exit the impeller;

receiving exiting cooling fluid at two or more involutes;

increasing a static pressure of the cooling fluid in the two or more involutes; and

reacting any loads generated by the two or more involutes and rotating impeller with one or more hydrodynamic bearings.

16. The method ofclaim 15, further comprising after increasing the static pressure of the cooling fluid, passing the cooling fluid to a cooling system.

17. The method ofclaim 15, wherein driving the impeller to rotate about an axis comprises generating an electromagnetic field to drive the impeller to rotate.

18. The method ofclaim 15, wherein increasing the static pressure of the cooling fluid in the two or more involutes comprises passing the cooling fluid through involute channels with increasing area.

19. The method ofclaim 15, wherein reacting any loads generated by the two or more involutes and rotating impeller with one or more hydrodynamic bearings comprises reacting any loads generated by the two or more involutes and rotating impeller with a journal bearing.

20. The method ofclaim 15, wherein reacting any loads generated by the double involute and rotating impeller with one or more hydrodynamic bearings comprises reacting any loads generated by the two or more involutes and rotating impeller with a thrust bearing.

21. A centrifugal pump comprising:

an impeller housing, the impeller housing comprising a fluid entrance to allow fluid to enter the impeller housing;

an impeller means to rotate in response to an electromagnetic field and to allow fluid to pass through during rotation;

a hydrodynamic bearing means positioned between the impeller and the impeller housing to support generated loads; and

a double involute coupled with the impeller housing and positioned to receive fluid exiting the plurality of impeller blades.

22. The centrifugal pump ofclaim 21, further comprising an electromagnetic field generating means to generate an electric field.

23. The centrifugal pump ofclaim 21, wherein the double involute further comprises:

two involute tongues to receive fluid from the fluid channels;

an involute throat to allow exit of fluid from the double involute; and

two involute channels to pass fluid from the involute tongues to the involute throat.

24. A centrifugal pump comprising:

an impeller housing, the impeller housing comprising a fluid entrance to allow fluid to enter the impeller housing;

an impeller located within the impeller housing comprising a plurality of impeller blades, a plurality of fluid channels between the impeller blades, and a motor magnet, wherein the impeller rotates within the impeller housing about a pump centerline in response to an electromagnetic field, and wherein further the fluid channels allow fluid to pass through when the impeller rotates;

one or more journal bearings positioned between the impeller and the impeller housing to support generated loads;

one or more thrust bearings positioned between the impeller and the impeller housing to support generated loads; and

two or more involutes coupled with the impeller housing and positioned to receive fluid exiting the plurality of impeller blades.

25. The centrifugal pump ofclaim 24, further comprising a motor stator positioned at least partially outside the impeller housing to generate an electromagnetic field in response to an electrical charge.

26. The centrifugal pump ofclaim 24, further comprising a motor stator positioned at least partially within the impeller housing to generate an electromagnetic field in response to an electrical charge.

27. The centrifugal pump ofclaim 24, wherein the impeller is at least partially comprised of an injection molded plastic material.

28. The centrifugal pump ofclaim 24, wherein the two or more involutes comprise a double involute, comprising:

two involute tongues to receive fluid from the fluid channels;

an involute throat to allow exit of fluid from the double involute; and

two involute channels to pass fluid from the involute tongues to the involute throat.

29. The centrifugal pump ofclaim 28, wherein the two involute tongues are positioned opposite each other.

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