HYBRID HYDROHYDRODYNAMIC THRUST BEARING SYSTEM AND METHOD - Patent application

Abstract

The system includes a fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, the fluid pressure transmission system including a cylindrical rotor configured to rotate circumferentially about a rotational axis and having oppositely disposed first and second end faces, a first end cover having an interface with the first end face of the cylindrical rotor, and a hybrid hydrodynamic bearing system configured to resist axial displacement of the cylindrical rotor.

Description

[Technical field]

[0001] The present invention relates to a hybrid hydrodynamic thrust bearing system and method. [Background technology]

[0002] This section is intended to introduce the reader to various technical aspects of the art that may be related to various aspects of the present invention, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. As such, it should be understood that these discussions should be considered in this light, and not as admissions of prior art.

[0003] The subject matter disclosed herein relates to systems and methods for an axial thrust bearing system having a hybrid hydrodynamic-hydrostatic design for use with the rotary pressure exchangers described herein, as well as pumps, turbines and other rotary machines.

[0004] Rotating equipment, such as pumps, can process (handle) a variety of fluids. In certain applications, axial pressure imbalances (i.e., the difference in average pressure between two axial surfaces) can exert substantial net forces on the rotating components of the rotating equipment. Also, the weight of the rotating components can generate axial forces. Various bearings can be used to facilitate the rotation of the rotating components of the rotating equipment. However, in situations requiring high pressure and / or difficult environments, the rotating equipment may require additional or increased support capacity and functionality. For example, in some situations, insufficient support capacity of the rotating equipment can result in axial contact between the rotating and stationary components, which can result in stalling, wear, stress, reducing the life of the equipment, and causing loss of efficiency. Therefore, it would be beneficial to provide the rotating equipment with mechanisms that provide additional load-bearing capacity or additional stiffness. Summary of the Invention

[0005] In one embodiment, a system is provided comprising a fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, the fluid pressure transmission system comprising a cylindrical rotor configured to rotate circumferentially about a rotational axis and having oppositely disposed first and second end faces, a first end cover having an interface with the first end face of the cylindrical rotor, and a hybrid hydrodynamic bearing system configured to resist axial displacement of the cylindrical rotor.

[0006] In another embodiment, a system is provided. The system includes a fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid. The fluid pressure transmission system includes a cylindrical rotor configured to rotate circumferentially about a rotation axis and having a first end face and a second end face disposed opposite each other, a first end cover having an interface with the first end face of the cylindrical rotor, and a hybrid hydrodynamic bearing system configured to resist axial displacement of the cylindrical rotor. The hybrid hydrodynamic bearing system includes a number of hydrodynamic pressure generating mechanisms disposed on the first end face of the cylindrical rotor and a number of hydrostatic pressure enhancing mechanisms disposed on a first surface of the first end cover. The hydrodynamic pressure generating mechanisms are configured to generate a hydrostatic force from the first end cover. The first end cover is ... end The hydrostatic pressure enhancing mechanism includes one or more grooves disposed on the surface. The hydrostatic pressure enhancing mechanism includes a plurality of ports.

[0007] In a further embodiment, a system is provided comprising a fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid. The fluid pressure transmission system comprises a cylindrical rotor configured to rotate circumferentially about a rotation axis and having oppositely disposed first and second end faces, a first end cover having an interface with the first end face of the cylindrical rotor, and a hybrid hydrodynamic bearing system configured to resist axial displacement of the cylindrical rotor. The hybrid hydrodynamic bearing system comprises both a number of hydrodynamic pressure generating features disposed on a first surface of the first end cover and a number of hydrostatic pressure enhancing features disposed on the first surface of the first end cover.

[0008] The various features, aspects, and advantages of the present invention will become better understood when the following detailed description is read in conjunction with the accompanying drawings, in which like characters represent like parts throughout and in which: [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a fluid pressure energy transmission system having a hybrid hydrodynamic bearing system according to one embodiment. [Diagram 2] FIG. 2 is a schematic diagram of a frac system having a hydraulic energy transmission system according to one embodiment. [Diagram 3] FIG. 3 is an exploded perspective view of one embodiment of a fluid pressure energy transmission system of FIG. 1 shown as a rotary pressure exchanger (PX) system. [Figure 4] FIG. 4 is an exploded perspective view of an embodiment of a rotatable PX in a first operating position. [Diagram 5] FIG. 5 is an exploded perspective view of an embodiment of a rotatable PX in a second operating position. [Figure 6] FIG. 6 is an exploded perspective view of an embodiment of a rotatable PX in a third operating position. [Figure 7] FIG. 7 is an exploded perspective view of a rotatable PX according to one embodiment in a fourth operating position. [Figure 8] FIG. 8 is a side perspective view of the end face of a rotor of a rotary PX having a dynamic pressure generating mechanism (e.g., a spiral groove) according to one embodiment. [Figure 9A] FIG. 9A is a side perspective view of one of both end faces of a rotor of a rotary PX having a dynamic pressure generating mechanism (eg, a spiral groove) according to one embodiment. [Figure 9B] FIG. 9B is a side perspective view of the other of both end faces of a rotor of a rotary PX having a dynamic pressure generating mechanism (eg, a spiral groove) of one embodiment. [Figure 10] FIG. 10 is a two-dimensional graph of the dynamic pressure distribution at the interface between the end faces of the rotor of FIG. 8 and the corresponding end covers. [Figure 11] FIG. 11 is a graph of fluid film thickness (eg, between the rotor end face and the end cover) and fluid force for different groove depths for a spiral groove on the rotor end face. [Figure 12] FIG. 12 is a side view of a rotatable PX end cover having a hydrostatic pressure enhancing feature (eg, port) of one embodiment. [Figure 13A] FIG. 13A is a side view of one of the end covers of a rotatable PX having hydrostatic pressure enhancing features (eg, ports) and dynamic pressure generating features (eg, spiral grooves) of one embodiment. [Figure 13B] FIG. 13B is a side view of the other opposite end cover of a rotatable PX having hydrostatic pressure enhancing features (eg, ports) and dynamic pressure generating features (eg, spiral grooves) of one embodiment. [Figure 14] FIG. 14 is a side view of a rotatable PX end cover having hydrostatic enhancement features (eg, ports and pockets) of one embodiment. [Figure 15] FIG. 15 is a side view of an end cover of a rotatable PX in one embodiment (eg, showing the hydrostatic channel network). [Figure 16] FIG. 16 is a perspective view of an end cover of a rotatable PX in one embodiment (eg, showing the hydrostatic channel network). [Figure 17]FIG. 17 is a partial cross-sectional view of an embodiment of a rotatable PX end cover (eg, having an orifice restrictor disposed within a channel of a hydrostatic channel network) taken within line 17-17 of FIG. [Figure 18] FIG. 18 is a two-dimensional graph of the hydrostatic pressure distribution at the interface between the rotor and end cover of FIG. [Figure 19] FIG. 19 is a two-dimensional graph of hydrostatic pressure distribution at the interface between a rotor and an end cover with a hybrid bearing system. [Figure 20] FIG. 20 is a two-dimensional graph of the hydrostatic pressure distribution at the interface between the rotor and the end cover lacking a hybrid bearing system. [Figure 21] FIG. 21 is a side view of an end face of a rotor of a rotary PX having a dynamic pressure generating mechanism (eg, a herringbone-shaped groove) according to one embodiment. [Figure 22] FIG. 22 is a side view of an end cover of a rotatable PX having both dynamic pressure generating and hydrostatic pressure enhancing features (eg, helical grooves and ports between the grooves) of one embodiment. [Diagram 23] FIG. 23 is a side view of an end cover of a rotatable PX having both dynamic pressure generating and hydrostatic pressure enhancing features (eg, helical grooves and ports located within the grooves) of one embodiment. [Figure 24] FIG. 24 is a side view of a rotatable PX end cover having both dynamic pressure generating and hydrostatic pressure enhancing features (eg, herringbone grooves and ports) of one embodiment. [Diagram 25] FIG. 25 is a side view of a rotatable PX end cover having both dynamic pressure generating and hydrostatic pressure enhancing features (eg, V-grooves and ports) of one embodiment. [Figure 26] FIG. 26 is a side view of an end cover of a rotatable PX having both dynamic pressure generating and hydrostatic pressure enhancing features (eg, tapered lands and ports) of one embodiment. [Figure 27] 27 is a perspective view of the end cover of FIG. 26. FIG. [Figure 28] 28 is a cross-sectional view of the end cover taken along line 28-28 of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] One or more specific embodiments of the present invention are described below. These described embodiments are merely exemplary of the present invention. Moreover, to simplify the description of these exemplary embodiments, not all features of an actual embodiment may be described herein. It will be recognized that in the development of any actual embodiment, as in any technical or design project, many implementation-specific decisions must be made to achieve developer-specific goals, such as adhering to system-related or business-related constraints, and these may vary from implementation to implementation. Moreover, it will be appreciated that the above development efforts may be complex and time-consuming, but are routine tasks of design, fabrication, and manufacture for those skilled in the art having the benefit of this disclosure.

[0011] As described in more detail below, embodiments disclosed herein generally relate to systems and methods for rotating systems that may be utilized in various industrial applications. The rotating systems disclosed herein may have a hybrid hydrodynamic and hydrostatic bearing system configured to provide additional support capacity, such that the rotating system provides sufficient load capacity to support certain rotating equipment, such as a rotor. Indeed, in certain industrial situations involving high pressure or other challenging applications, the bearing system of the rotating system may not have sufficient load capacity or capability to support rotating equipment, such as a rotor. Such a situation may result in stalling of the rotor and / or contact and friction between parts of the bearing system, thereby resulting in loss of efficiency, wear, stress, and / or reduced life of the rotating equipment. Accordingly, embodiments disclosed herein may provide a rotating system with a hybrid hydrodynamic and hydrostatic bearing system in an axial bearing region (e.g., an interface between a rotor and an end cover of a fluid pressure energy transmission system) configured to handle additional bearing or load capacity, which may provide additional axial load capacity and greater stiffness to support rotating equipment, such as a rotor. In particular, hybrid hydrodynamic and hydrostatic bearing systems may be utilized in industrial applications having relatively high pressures (e.g., about 68,947 kPa or 10,000 psi) and / or in more challenging applications such as, for example, pressure exchangers, axial piston pumps, steam turbine thrust bearings, gas turbine thrust bearings, and aircraft engines. In certain embodiments, hybrid hydrodynamic and hydrostatic bearing systems may be utilized in non-rotating equipment.

[0012] In certain embodiments, the rotating system may have a fluid pressure energy transmission system configured to handle various fluids. In particular, the fluid pressure energy transmission system may transmit work and / or pressure between a first fluid and a second fluid via a hybrid hydrodynamic bearing system, which may be used to facilitate rotation of a rotating component of a rotating machine. In general, the hydrostatic bearing system in the fluid pressure energy transmission system may be actuated by a fluid source (e.g., high pressure bearing fluid) introduced between a rotor and an end cover (e.g., a support for the rotor). The high pressure of the fluid source may be configured to support the rotor on a thin fluid film and facilitate rotation of the rotating component. In particular, as the rotor moves away from the end cover, an axial clearance area between the rotor and the end cover may increase. The increased axial clearance area may allow the high pressure fluid to escape, thereby reducing the pressure acting on the rotor. Similarly, when the axial clearance area between the rotor and the end cover is small, a high pressure fluid is generated in the axial bearing area. Hybrid hydrodynamic bearing systems that rely on high rotor speeds (in conjunction with mechanisms that form pressure dams) similarly support the rotor on a thin film of fluid to facilitate rotation of rotating components (e.g., acting on the end covers and rotor).

[0013] Hybrid hydrodynamic bearings enhance the features of both hydrostatic and hydrodynamic bearing systems. For example, at relatively high speeds (e.g., 10,000 rpm), hybrid hydrodynamic bearings perform as superior hydrodynamic bearings, while at low and medium speeds (e.g., below 5,000 rpm), hybrid bearings perform as superior hydrostatic bearings. At all operating speeds, hybrid bearings improve dynamic stability (e.g., compared to pure hydrodynamic bearing systems) and improve cooling capacity or viscous heat removal, while enhancing load-bearing capacity and stiffness. Hybrid bearings also provide adjustment capability and self-compensating behavior of the bearing thin film pressure to accommodate dynamic motion (e.g., of components such as rotor and housing). In addition, hybrid bearings provide reliable operation (e.g., hydrodynamic bearing systems operate even if hydrostatic bearing systems suddenly stop due to blockage or clearance closure). In addition, hybrid bearings operate without external moving parts and are not limited by fatigue. In addition, hybrid bearings are more resistant to particulates (e.g., sand) in the fluid. Additionally, hybrid bearings are easy to machine and manufacture.

[0014] In certain embodiments, a hybrid hydrodynamic and hydrostatic bearing system may have hydrostatic pressure generating features located on the end faces of the rotor along with hydrostatic pressure enhancing features located on the end covers (e.g., of a rotary isostatic pressure exchanger). In other embodiments, a hybrid bearing system may have both hydrostatic pressure generating features and hydrostatic pressure enhancing features located only on the end covers with no features on the end faces of the rotor. The hydrostatic pressure generating features may include spiral grooves, herringbone grooves, tapered lands, among other features. The hydrostatic pressure enhancing features may include ports, ports associated with pockets, ports associated with both orifice flow restrictors and pockets, among other features.

[0015] The hydraulic energy transmission system may include a hydraulic pressure exchange system, such as a hydraulic supercharger, a hydraulic pump, or a rotary pressure exchanger (PX). In some embodiments, the pressures of the volumes of the first and second fluids may not be perfectly equalized. Thus, in certain embodiments, the PX may operate isobarically, or the PX may operate substantially isobarically (e.g., the pressures are equal within about ±1, 2, 3, 4, 5, 6, 7, 8, 9, or 10%). In certain embodiments, a first pressure of the first fluid (e.g., pressure exchange fluid, dynamic fluid, etc.) may be higher than a second pressure of the second fluid (e.g., corrosive fluid, etc.). For example, the first pressure may be about 5,000 kPa to 25,000 kPa, 20,000 kPa to 50,000 kPa, 40,000 kPa to 75,000 kPa, 75,000 kPa to 100,000 kPa, or greater than the second pressure. Thus, the PX may be used to transmit pressure from a first fluid (e.g., a pressure exchange fluid, a drive fluid, etc.) at a relatively high pressure to a second fluid (e.g., a corrosive fluid, etc.) at a relatively low pressure. In particular, during operation, the hydraulic energy transmission system may help to block or limit contact between the corrosive fluid and other equipment (e.g., a pump) in an industrial application. By preventing or limiting contact between the pump and the corrosive fluid, the hydraulic energy transmission system may increase the life and performance while reducing wear and tear of various high pressure pumps in various industrial applications, as described in more detail below.

[0016] 1 is a schematic diagram of an embodiment of a fluid pressure energy transmission system 10. In particular, in the illustrated embodiment, the fluid pressure energy transmission system 10 (e.g., a fluid pressure supercharger or PX) may be configured to transfer energy from a first fluid to a second fluid. Furthermore, in certain embodiments, the fluid pressure energy transmission system 10 may include a hybrid hydrodynamic bearing system 12 configured with features that help provide additional support capacity and / or additional axial load capacity to the fluid pressure energy transmission system 10.

[0017] In certain embodiments, the hydraulic energy transmission system 10 may be configured to include a rotary PX 20 configured to receive a first fluid and a second fluid. It should be noted that references to various directions (e.g., axial 32, radial 142, and circumferential 148) may be referenced in the following description. In certain embodiments, a high pressure pump may be configured to pump a first fluid at high pressure to the hydraulic energy transmission system 10. For example, as shown, the first fluid may be provided as a high pressure first fluid inlet 14 to the hydraulic energy transmission system 10. Additionally, in certain embodiments, a low pressure pump may be configured to pump a second fluid at low pressure to the hydraulic energy transmission system 10. For example, as shown, the second fluid may be provided as a low pressure second fluid inlet to the energy transmission system 10. In operation, the hydraulic energy transmission system 10 may be configured to transfer pressure between the first fluid and the second fluid.

[0018] As used herein, the pressure exchanger 20 may be generally defined as a device that transfers fluid pressure between a high pressure inlet stream and a low pressure inlet stream with greater than about 90% efficiency without utilizing centrifugal technology. In this context, high pressure refers to a pressure greater than the low pressure. The low pressure inlet stream of the PX 20 may be pressurized to exit the PX at a high pressure (e.g., at a pressure greater than the low pressure inlet stream), and the high pressure inlet stream may be depressurized to exit the PX 20 at a low pressure (e.g., at a pressure less than the high pressure inlet stream). Additionally, the PX 20 may operate by the high pressure fluid applying a force directly to the low pressure fluid to pressurize the low pressure fluid, with or without a fluid separator between the high pressure and low pressure fluids. Examples of fluid separators that may be used with the PX include, but are not limited to, pistons, bladders, diaphragms, and the like. In certain embodiments, the pressure exchanger 20 may be a rotating device. Rotary pressure exchangers 20, such as those manufactured by Energy Recovery, San Leandro, California, may not have any isolation valves since effective valving is accomplished internally to the device via relative motion of the rotor with respect to the end covers, as described in detail below with respect to Figures 4-7. Rotary PXs 20 may be designed to operate with internal pistons to isolate the fluids and transfer pressure with relatively little mixing of the inlet fluid streams. Reciprocating PXs may have pistons that move back and forth within cylinders to transfer pressure between the fluid streams. In the disclosed embodiments, any PX or multiple PXs 20 may be used, such as, but not limited to, rotary PXs, reciprocating PXs, or any combination thereof. Additionally, the PXs 20 may be located on a skid separate from other components of the fluid processing system, which may be desirable in situations where the PXs 20 are being added to an existing fluid processing system.

[0019] As mentioned above, in certain embodiments, the fluid pressure energy transmission system 10 may have a hybrid hydrodynamic bearing system 12 configured to help facilitate rotation of a rotating component in the system, such as the rotor 44. Generally, a high pressure process fluid (e.g., the first fluid and / or the second fluid) may act as a bearing fluid and be utilized to support an axial load. The rotor 44 of the PX 20 is enclosed within the plenum region 22 of the housing 21. The rotor 44 is disposed with a sleeve 24. The inner wall of the sleeve 24 of the PX system 20 and the outer wall of the rotor 44 disposed within the PX system 20 define a radial gap 26 between the sleeve 24 and the rotor 44. The axial bearing region 28 includes an axial gap 29 (e.g., tens of microns) between the rotor 44 and the end cover 30. The high pressure bearing fluid introduced into the plenum region 22 may be configured to support the rotor 44 on a thin fluid film and may be configured to facilitate rotation of the rotor 44. In particular, as the rotor 44 moves axially 32 toward the end cover 30 due to an external force caused by a fluid pressure differential acting on the rotor 44, the axial clearance area 34 between the rotor 44 and the end cover 30 may decrease. The reduction in the axial clearance area 34 increases the pressure in the bearing fluid film (which has an approximately inverse cubic relationship with the bearing film thickness), thereby increasing the force acting on the rotor 44 in a direction opposite to the original external force that caused the rotor 44 to move and reduce the bearing clearance 29. This new bearing force increases the axial clearance area 34 by a larger amount, bringing the rotor 44 to a new force equilibrium position. Thus, this is essentially a "self-compensating" mechanism that prevents the rotor 44 from rubbing against the end cover 30 and potentially seizing the system. Similarly, when an external force forces the rotor 44 to move axially 32 away from the bearing, the axial clearance area 34 between the rotor 44 and the end cover 30 increases, reducing the pressure in the bearing fluid film.This reduces the forces acting on the rotor 44 from the bearing membrane returning the rotor 44 to an equilibrium position and avoids rubbing on the opposite side of the rotor 44. In this manner, the components of a hybrid hydrodynamic bearing may cooperate to create a stiff bearing system that resists axial displacement of the rotor 44 and facilitates stable rotation of the rotor 44.

[0020] FIG. 2 is a schematic diagram of an embodiment of a frac system 46 (e.g., a fluid treatment system) that may be used with the hydraulic energy transmission system 10. In operation, the frac system 46 enables well completion operations to increase the release of oil and gas in a rock formation. The frac system 46 may include one or more first fluid pumps 48 and one or more second fluid pumps 50 coupled to the hydraulic energy transmission system 10. As discussed above, the hydraulic energy transmission system 10 may include a hydraulic supercharger, a rotary PX, a reciprocating PX, or any combination thereof. Additionally, the hydraulic energy transmission system 10 may be located on a skid separate from other components of the frac system 46, which may be desirable in situations where the hydraulic energy transmission system 10 is being added to an existing frac system 46. During operation, the hydraulic energy transmission system 10 transmits pressure without substantial mixing between a first fluid (e.g., a non-proppant-bearing fluid) pumped by the first fluid pump 48 and a second fluid (e.g., a proppant-bearing fluid or a frac fluid) pumped by the second fluid pump 50. In this manner, the hydraulic energy transmission system 10 enables the frac system 46 to pump high pressure frac fluid into the well 52 to liberate oil and gas while preventing or limiting wear on the first fluid pump 48 (e.g., a high pressure pump). Additionally, because the hydraulic energy transmission system 10 is configured to be exposed to the first and second fluids, the hydraulic energy transmission system 10 may be made of materials that are resistant to corrosive and abrasive substances in either of the first and second fluids. For example, the hydraulic energy transmission system 10 may be made from a ceramic (e.g., a cermet such as an alumina, carbide, oxide, nitride, or boride hard phase) in a metal matrix (e.g., cobalt (Co), chromium (Cr), or nickel (Ni), or any combination thereof), such as tungsten carbide in a matrix of cobalt chromium (CoCr), nickel (Ni), nickel chromium (NiCr), or cobalt (Co).

[0021] Although the use of the fluid pressure energy transmission system 10 (e.g., PX) having the hybrid hydrodynamic bearing system 12 has been described in the context of a frac system 46, the fluid pressure energy transmission system may be utilized in other types of applications (e.g., desalination, mud pumping, etc.) Additionally, the hybrid hydrodynamic bearing system 12 may be utilized with other types of equipment, including liquid and gas processing turbomachinery, steam turbines, gas turbines, aircraft engines, and carbon dioxide compressors, among others.

[0022] Returning to the fluid pressure energy transmission system 10 of FIG. 1, the PX system 20 may be further understood in the discussion of FIGS. 3-7. FIG. 3 is an exploded view of a rotary PX 20 in one embodiment. In the illustrated embodiment, the rotary PX 20 may include a generally cylindrical body 54 having a housing 56 and a rotor 44. The rotary PX 20 may also include two end structures 58 and 60 that include manifolds 62 and 64. The manifold 62 may include an inlet port 66 and an outlet port 68, and the manifold 64 may include an inlet port 70 and an outlet port 72. For example, the inlet port 66 may be used to receive a first fluid at high pressure and the outlet port 68 may be used to direct the first fluid at low pressure away from the PX 20. Similarly, the inlet port 70 may be used to receive a second fluid at low pressure and the outlet port 72 may be used to direct the second fluid at high pressure away from the PX 20. The end structures 58 and 60 include generally planar end plates 31, 33 (e.g., end covers 30) that are adapted to be disposed within the manifolds 62 and 64, respectively, and to be in fluid-sealing contact with the rotor 44. The rotor 44 may be cylindrical and disposed within the housing 56 and arranged for rotation about a longitudinal axis 74 of the rotor 44. The rotor 44 may have a plurality of channels 76 extending substantially longitudinally therethrough with openings 78 and 80 at each end symmetrically disposed about the longitudinal axis 74. The openings 78 and 80 of the rotor 44 are arranged in fluid communication with the end plates 62 and 64 and the inlet and outlet openings 82 and 84 and the openings 86 and 88 to alternately fluidly expose high and low pressure fluids to the respective manifolds 62 and 64 during rotation. The inlet ports 66 and 70 and outlet ports 68 and 72 of the manifolds 62 and 64 form at least one pair of ports for high pressure fluid in one end element 58 or 60 and at least one pair of ports for low pressure fluid in the opposing end element 58 or 60. The end plates 62 and 64 and the inlet openings 82 and 86 and outlet openings 84 and 88 are designed to have a vertical flow cross section in the form of an arc or segment of a circle.

[0023] With respect to PX 20, plant operators can control the degree of mixing between the first and second fluids and use this to improve the operability of the fluid processing system. For example, by varying the ratio of the first and second fluids entering PX 20, plant operators can control the amount of fluid mixing in the fluid processing system. In certain embodiments, the ratio of the drive fluid to the corrosive fluid can be varied to control the amount of mixing in the fluid processing system. In other embodiments, plant operators can control the angular velocity of rotation of rotor 44 to control the amount of mixing. Three features of PX 20 that affect mixing are (1) the aspect ratio of rotor channel 76, (2) the short duration of exposure between the first and second fluids, and (3) the creation or presence of a fluid barrier (e.g., interface) between the first and second fluids in rotor channel 76. First, rotor channel 76 is generally long and narrow, stabilizing the flow in PX 20. Furthermore, the first and second fluids may move through the channel 76 in a plug flow regime with very little axial mixing. Second, in certain embodiments, at a rotor speed of about 1200 RPM, the contact time between the first and second fluids may be less than about 0.15 seconds, 0.10 seconds, or 0.05 seconds, again limiting flow mixing. Third, a small portion of the rotor channel 76 is used for pressure exchange between the first and second fluids. Thus, a volume of fluid remains within the channel 76 as a barrier between the first and second fluids. All of these mechanisms may limit mixing within the PX 20.

[0024] 4-7 are exploded views of an embodiment of the rotary PX 20 showing the sequence of positions of a single channel 76 in the rotor 44 as the channel 76 rotates through a complete cycle, which aids in understanding the rotary PX 20. It should be noted that FIGS. 4-7 are simplified views of the rotary PX 20 showing one channel 76, and the channel 76 is shown to have a circular cross-sectional shape. In other embodiments, the rotary PX 20 may have multiple channels 76 (e.g., 2-100) having different cross-sectional shapes. Thus, FIGS. 4-7 are simplifications for purposes of explanation, and other embodiments of the rotary PX 20 may have different configurations than those shown in FIGS. 5-8. As described in more detail below, the rotary PX 20 facilitates a fluid pressure exchange of pressure between two liquids by momentary contact within a rotating chamber. In certain embodiments, this exchange occurs at high speeds, resulting in very little mixing of the liquids and very high efficiency.

[0025] In FIG. 4, the channel opening 78 is in fluid pressure communication with an opening 84 in the end plate 31 and therefore in fluid pressure communication with the manifold 62 in the first rotational position of the rotor 44, and the opening 80 of the opposite channel is in fluid pressure communication with an opening 88 in the end plate 33 and therefore in fluid pressure communication with the manifold 64. As will be described below, the rotor 44 rotates in a clockwise direction as indicated by the arrow 90. As shown in FIG. 4, a second fluid 92 at low pressure passes through the end plate 31 and enters the channel 76, and the second fluid 92 pushes the first fluid 94 out of the channel 76, through the end plate 31 and out of the rotary PX 20. In certain embodiments, the first fluid 94 and the second fluid 92 contact each other at an interface 96, and the duration of the contact is short, thereby minimizing mixing of the liquids. In certain embodiments, the interface 96 may be a direct contact interface, since the second fluid 92 directly contacts the first fluid 94. In other embodiments, the interface 96 may include a dynamic barrier that is utilized to separate the first and second fluids. In other embodiments, the asymmetric flow of the first and second fluids may result in a certain amount of mixing between the first and second fluids.

[0026] 5, channel 76 rotates clockwise through an arc of approximately 90 degrees such that outlet 80 is blocked between openings 86 and 88 in end plate 33 and outlet 78 of channel 76 is located between openings 82 and 84 in end plate 31 and is therefore blocked from fluid pressure communication with manifold 62 of end structure 58. A low pressure second fluid 92 is therefore contained within channel 76.

[0027] In Figure 6, channel 76 has rotated through an arc of approximately 180 degrees from the position shown in Figure 4. Opening 80 is in fluid pressure communication with opening 86 in end plate 33 and in fluid pressure communication with manifold 64, and opening 78 of channel 76 is in fluid pressure communication with opening 82 in end plate 31 and in fluid pressure communication with manifold 62 of end structure 58. The liquid in channel 76, which was at the pressure of manifold 64 of end structure 60, transfers this pressure through outlet 78 and opening 82 to end structure 58, reaching the pressure of manifold 62 of end structure 58. Thus, the high pressure first fluid 94 pressurizes and displaces second fluid 92.

[0028] 7, channel 76 has rotated through an arc of approximately 270 degrees from the position shown in FIG 4, with openings 70 and 72 of channel 68 now being between openings 82 and 84 in end plate 31 and between openings 86 and 88 in end plate 33. Thus, high pressure first fluid 94 is contained within channel 76. As channel 76 has rotated through an arc of approximately 360 degrees from the position shown in FIG 4, second fluid 92 displaces first fluid 94, restarting the cycle.

[0029] The rotary PX system 20 and hybrid hydrodynamic bearing system 12 may be further understood with reference to the descriptions of Figures 8-21. In certain embodiments, both end faces 150 of the rotor 40 may have a hydrodynamic pressure generating feature 152 and one or both of the plurality of end covers 30 include a hydrostatic pressure enhancing feature 184 to form a hybrid hydrodynamic pressure bearing system. In other embodiments, only one or both of the plurality of end covers 30 include both the hydrodynamic pressure generating feature 152 and the hydrostatic pressure enhancing feature 184 to form a hybrid hydrodynamic pressure bearing system.

[0030] 8 is a side perspective view of an end face 150 of rotor 44 of PX 20 having a dynamic pressure generating feature 152 (e.g., a spiral groove) according to one embodiment. As shown, dynamic pressure generating feature 152 is a groove 154 (e.g., a spiral groove). A first set 156 of grooves 154 (e.g., inward pumping grooves) are disposed circumferentially 148 about longitudinal axis 74 along an outer periphery or diameter 158 of end face 150 (e.g., radially outward of channel 76). A second set 160 of grooves 154 (e.g., outward pumping grooves) are disposed circumferentially 148 about longitudinal axis 74 along an inner diameter 162 of end face 150 (e.g., radially inward of channel 76). The number and shape of grooves 154 can vary.

[0031] The spiral groove 154 includes a shallow portion 164, a deep portion 166 (i.e., longer than the shallow portion 164), and a dam portion 168 disposed between the shallow portion 164 and the deep portion 166. The spiral groove 154 generates dynamic pressure by converting an increase in momentum of the fluid along the spiral into an increase in dynamic pressure as the fluid impacts the dam portion 168. For example, as the rotor 44 rotates as shown by arrow 170, the fluid accelerates along each of the first set 156 and second set 160 of grooves 154 (as shown by arrows 172, 174, respectively) until it impacts the dam portion 168 (e.g., generating a pumping action). At the dam portion 168, the kinetic energy is converted into pressure, resulting in a high pressure spike that, when integrated over the area of ​​the groove, generates a force that pushes the rotor 44 in the axial direction 32 away from the end cover 30. The groove design features (e.g., groove helix angle, dam to land ratio, groove pitch, groove depth, etc.) can be optimized to fine-tune the magnitude of this pressure spike and therefore the amount of drag force generated by the grooves. The direction of the helix angle of the inward pumping grooves 156 is opposite to the direction of the helix angle of the outward pumping grooves 160. This ensures that the fluid is swirled by the grooves in the ID (for 156) and OD (for 160) directions, providing high kinetic energy to the bearing fluid just before it hits the respective dam sections radially inward (for 156) and radially outward (for 160). The presence of both the first set 156 and second set 160 of grooves 154 ensures that the rotor 44 is supported across the entire end face 150, reducing the possibility of rubbing against the end cover 30 due to temporary tilt or ND2 vibration (rotor face bending mode) in the rotor 44.

[0032] The Reynolds equation governs the physics of thin film flow. The Reynolds equation is as follows:

number

[0033] 9A and 9B are side perspective views of both end faces 150, 151 of a rotor 44 of a rotary PX 20 having one embodiment of a dynamic pressure generating feature 152 (e.g., helical grooves). FIG. 9A is similar to FIG. 8, except that the rotor end face 150 only includes a single set 156 of grooves 154 on the outer periphery 158. In certain embodiments, both end faces 150, 151 may include grooves along the inner diameter similar to FIG. 8. FIG. 9B is the opposite end face 151 of the rotor 44. As shown, some of the grooves 154 on the end face 151 are mirror images with respect to the grooves 154 on the end face 150 about a plane 153 that cuts the rotor 44 axially in half. Some of the grooves 154 on the end faces 150, 151 are mirror images because the direction of rotation 170 relative to the end faces 150, 151 is opposite. This allows inward and outward pumping to function properly.

[0034] FIG. 10 is a representative graph of dynamic pressure distribution (e.g., on a micron scale) in the bearing fluid film between the end face 150 of FIG. 8 and the corresponding end cover 30. For example, a high pressure spike (e.g., as indicated by area 175) is visible at the dam portion 168 of the first set 156 of grooves 154 due to kinetic energy being converted to pressure. FIG. 11 is a graph 176 of generated fluid forces and fluid film thickness (e.g., between the rotor end face 150 and the end cover 30) for different groove depths of the spiral grooves 154 on the rotor end face 150. Graphs 178, 180, and 182 represent groove depths of 10 μm, 20 μm, and 30 μm, respectively, for the spiral grooves 154. Graph 176 shows that high bearing stiffness (change in generated fluid force per unit change in film thickness) can be obtained with the spiral grooves 154. In particular, hydrodynamic forces increase as the gap between the rotor 44 and the end cover 30 decreases, creating a strong resistive force pushing the rotor 44 away from the end cover 30 .

[0035] In conjunction with the dynamic pressure generating features 152 on the rotor end face 150, hydrostatic pressure intensifying features may be present on the surface of the end cover 30 that interfaces with the rotor end face 150. FIGS. 12-14 are side views of the end cover 30 of the rotary PX 20 having one embodiment of a hydrostatic pressure intensifying feature 184. As shown in FIGS. 12-14, the hydrostatic pressure intensifying feature 184 is disposed on the surface 186 (surface 187) of the end cover 30 that interfaces with the rotor end face 150 (or rotor end face 151). The end cover 30 includes openings 188, 190 and, in certain embodiments, an annular groove 192 (see FIGS. 12 and 14). The annular groove forms a plenum that receives a fluid (e.g., HP first fluid) to attempt to equalize the circumferential pressure distribution around the rotor 44. As shown in FIGS. 12-14, the hydrostatic pressure intensifying feature 184 includes a port or opening 194. The number and shape of the ports 194 can vary. Specifically, the first set 196 of ports 194 are disposed adjacent to the grooves 192, such that the ports 194 are disposed inwardly from the grooves 192 in the radial direction 146 and radially outwardly (e.g., relative to the longitudinal axis 74) from the openings 188, 190. The second set 198 of ports 194 are disposed inwardly from both the grooves 192 and the openings 188, 190 in the radial direction 146.

[0036] The ports 194 of the first set 196 and the second set 198 form a hydrostatic channel network 195, as shown in Figures 15 and 16. Each port 194 of both the first set 196 and the second set 198 is connected to a respective channel 197 (e.g., an L-shaped channel) that extends through the end cover 30. In particular, the channel 197 includes a first portion 199 that extends axially 32 from the surface 186 into the end cover 30 and a second portion 201 that extends radially 146 to the outer periphery or diameter 203 of the end cover 30 and is connected to the first portion 199. High pressure fluid flows from the outer periphery 203 through the first portion 199 (e.g., via an inlet 209) into the second portion 201 of the channel 197 and exits the port 194 (e.g., an outlet) in the radial direction 146, creating a pressure rise in the axial bearing membrane. In certain embodiments, the outer diameter ports 194 of the first set 196 (e.g., as shown in FIG. 15 ) may share a portion (e.g., second portion 201) of the same channel 197 of a radially adjacent inner diameter port 194 of the second set 198. In certain embodiments, each port 194 of both the first set 196 and the second set 198 (e.g., as shown in FIG. 16 ) may be connected to a separate channel 197. During the manufacture of the channel 197 in the end cover 30, the second portion 201 has a diameter 205 that is larger than the diameter 207 of the first portion 199. The pressure drop across each channel 197 is defined by the respective diameters 205, 207 and the lengths of the portions 201, 199, and is therefore optimized so that the pressure at the port outlet is high enough to generate an effective hydrostatic bearing action. This ensures that the portions 199, 201 merge with each other to form the channel 197. In certain embodiments, the channel 197 may be machined (eg, electro-discharge machined).

[0037] 12, 13A, and 13B, the first set 196 and second set 198 of ports 194 are radially aligned 146 (e.g., relative to the longitudinal axis 74) with the first set 156 and second set 160 of grooves 154 of the rotor end face 150 of FIG. 8. In certain embodiments, the ports 194 and grooves 154 together act as a hybrid hydrodynamic-hydrostatic bearing system. The fluid forces generated by the grooves 154 supplement the hydrostatic forces generated by the ports 194. It is important to note that the hydrostatic pressure enhancing features (e.g., reference numeral 184) provide additional load carrying capacity through high pressure fluid supplied through these ports 194, while the hydrostatic pressure generating features provide additional load carrying capacity through the rotation of the rotor 44 and the conversion of kinetic energy to pressure increase. The dynamic pressure generating mechanism also provides higher fluid film stiffness than can be achieved with hydrostatic bearings alone, thus providing relatively high resistance to rubbing events caused by high speed transient movements of the rotor 44 due to various vibration modes.

[0038] In certain embodiments, the end cover 30 may have both a dynamic pressure generating feature and a hydrostatic pressure enhancing feature. Figures 13A and 13B are side views of both end covers 30 of a rotary PX 20 having one embodiment of a hydrostatic pressure enhancing feature 184 (e.g., a port) and a dynamic pressure generating feature 152 (e.g., a helical groove 154). Surfaces 186, 187 of the end cover 30 interface with both end faces 150, 151 of the rotor 44, respectively. The end cover 30 has a first set 196 of helical grooves 154 adjacent to the ports 194. As shown, the first set 196 of ports 194 are distributed in the circumferential direction 148 every few grooves 154 (i.e., a port is located between every few grooves 154). In certain embodiments, a port 194 may be located between each adjacent pair of grooves 154. Some of the grooves 154 on end cover surface 186 are mirror images of the grooves 154 on end cover surface 187 about plane 153 for the same reasons described above for end rotor end faces 150, 151. The grooves 154 of end cover 30 function similarly to those on rotor 44 end faces 150, 151.

[0039] In certain embodiments, the hydrostatic pressure enhancement mechanism 184 may have ports 194 disposed within pockets or recesses 200 as shown in FIG. 14. The shape and number of pockets 200 may vary. As shown, the pockets have a rectangular shape. The number of ports 194 per pocket 200 may vary. Additionally, the location of the ports 194 relative to the pockets 200 may vary. The pockets 200 may have a depth (e.g., in the axial direction 32) of about 30 μm to 100 μm. The pockets 200 provide improved pressure distribution and stiffness. The pockets 200 help to avoid constricting the flow through the bearing membrane in the event of complete closure of the gap between the end cover 30 and the rotor 44. In certain embodiments, the ports 194 (e.g., in FIGS. 12-14) may have an orifice flow restrictor 211 disposed within a channel 197 associated with the port 194. As shown in FIG. 17, the orifice flow restrictor 211 is disposed in the channel 197 associated with the port 194 in both the first set 196 and the second set 198. In particular, the orifice flow restrictor 211 is disposed in the first portion 199. In certain embodiments, the orifice flow restrictor 211 may be disposed in the second portion 201. The orifice flow restrictor 211 provides the pocket pressure with the ability to adjust itself to the applied load. For example, if a very high load is applied to the rotor 44 that forces the rotor 44 to close the bearing gap, the outflow from the bearing membrane is almost zero and there is no flow across the orifice. This allows the pressure in the hydrostatic pocket to rise with negligible pressure drop across the orifice. The increased pocket pressure pushes the rotor 44 away from the end cover 30, providing a self-correcting behavior. When the axial thrust on the rotor 44 drops to a negligible value, the increased bearing clearance allows a large leakage flow through the bearing clearance with the only resistance to flow being provided by the orifice flow restrictor 211. This increases the flow rate until the pressure drop across the orifice is sufficient to reduce the pocket pressure, which also returns the rotor 44 to an equilibrium position via a self-correcting behavior.The orifice flow restrictor 211 and pocket 200 may be machined (e.g., EDM) onto the end cover 30. In certain embodiments, an external orifice flow restrictor may be attached to the opening of a hydrostatic port located on the OD of the end cover 30.

[0040] Returning to FIG. 14 , the hydrostatic stiffening mechanism 184 (e.g., the port 194, the pocket 200, the orifice flow restrictor, etc.) creates a pressure rise in the axial bearing membrane when high pressure fluid is pumped through the port 194 and / or the orifice flow restrictor. In operation, the port 194 utilizes the pressure of the HP fluid (e.g., the first fluid or the second fluid depending on the end cover 30) to exert a force against the rotor 44 to eliminate and / or substantially reduce the possibility of the rotor 44 contacting the end cover 30. In particular, as the rotor 44 is driven towards the end cover 30 via a first external force (and unintended force), the localized pressure in the axial bearing (i.e., the hydrostatic stiffening mechanism 184) increases, thereby generating a second internal force (and intended force) on the rotor 44 that is equal to or slightly greater than the first force. As a result, the force generated by the axial bearing maintains the rotor 44 in a balanced position.

[0041] FIG. 18 is a two-dimensional graph of hydrostatic pressure distribution at the interface between the rotor and end cover 30 of FIG. 12. As shown, high pressure areas 213 exist in the thin film areas corresponding to the ports 194 of the first set 196. FIG. 19 is a two-dimensional graph of hydrostatic pressure distribution at the interface between a rotor and an end cover (e.g., end cover 30 of FIG. 13A) having a hybrid bearing system. As shown in FIG. 19, high pressure areas 215 exist in the thin film areas corresponding to the ports 194 and the spiral grooves 154 of both the first set 196 and the second set 198. FIG. 20 is a two-dimensional graph of hydrostatic pressure distribution at the interface between a rotor and an end cover lacking a hybrid bearing system. As shown in FIG. 20, there are no high pressure areas observed in FIG. 19. These high pressure areas 215 of FIG. 19 provide additional load carrying capacity compared to the end cover 30 without hybrid bearings.

[0042] FIG. 21 illustrates an alternative groove shape for the dynamic pressure generating feature 152 on the end face 150 of the rotor 44. The dynamic pressure generating feature 152 includes a herringbone shaped groove 202 that is circumferentially disposed 148 about the longitudinal axis 74 along the outer periphery or diameter 158 of the end face 150 (e.g., radially outward of the channel 76). The groove 202 includes a central circumferential portion 204 and bifurcated portions 206 that extend at an angle (e.g., an oblique angle) away from the central circumferential portion 204 to form a Y-shaped portion about the groove 202. The herringbone shaped groove 202 provides bi-directional tilt or deflection compensation capability due to the Y-shaped bifurcations of the groove 202. Thus, when the rotor 44 tilts or deforms toward the inner diameter, the bifurcated portions 206 that are inward in the radial direction 146 are supported by a relatively small film thickness. This causes the inner branch 206 to exert a greater dynamic pressure in the radial direction 146 than the outer branch 206, which pushes the rotor 44 back to its equilibrium position. When the rotor 44 tilts or deforms toward the outer diameter, the outer branch 206 is supported by a smaller thickness in the radial direction 146. This causes the outer branch 206 to exert a greater dynamic pressure than the inner branch 206, which pushes the rotor 44 back to its equilibrium position. The several Y-shaped branchings help accelerate the flow toward the dam section located at the end of each of these branches 206. The central circumferential portion 204 of the groove 202 helps to circulate the flow evenly over all of the Y-shaped sections, avoiding any narrowing of the channel that could create a moment imbalance on the rotor 44. The central circumferential portion 204 also removes heat generated at the Y-shaped branchings. In particular, the central circumferential portion 204 provides cooling flow to dissipate the highly viscous heat resulting from the action of dynamic pressure to avoid warping or thermal cracking of the surface. The grooves 202 may be machined (e.g., electro-discharge machined) on the end face 150.

[0043] In certain embodiments, the grooves 202 on the end face 150 may be utilized in conjunction with the hydrostatic strengthening features 184 on the end cover 30. For example, the grooves 202 may be utilized in conjunction with the hydrostatic strengthening features 184 (e.g., ports, pockets, etc.) on the end cover 30 of Figures 12-14. In certain embodiments, several of the ports 194 on the end cover 30 may be aligned with the central circumferential portion 204 in the radial direction 146.

[0044] In certain embodiments, both the dynamic pressure generating features 152 and the hydrostatic pressure enhancing features 184 (e.g., grooves and ports) may be located only on the surface 186 of the end cover 30 without the features 152, 184 located on the rotor end face 150 having an interface. Figures 22 and 23 are side views of an end cover 30 of a rotary PX 20 having both the dynamic pressure generating features 152 and the hydrostatic pressure enhancing features 184 (e.g., helical grooves 208 and ports 210 between some of the grooves 208) of one embodiment. A first set 212 of grooves 208 (e.g., inward pumping grooves) are located circumferentially 148 with respect to the longitudinal axis 74 on the surface 186 (e.g., between the channel 76 and the groove 192 in the radial direction 146). A second set 214 of grooves 208 (e.g., outward pumping grooves) are disposed circumferentially 148 with respect to the longitudinal axis 74 on the surface 186 (e.g., inwardly of both the channel 76 and the grooves 192 in the radial direction 146). The number and shape of the grooves 208 can vary. Functionally, the grooves 208 operate similarly to the grooves 154 of FIG. 8. As shown in FIG. 22, several ports 210 are disposed circumferentially on the surface 180 between several grooves 208 (e.g., in circumferential alignment with several grooves 208). As shown in FIG. 22, several ports 210 are disposed between every few grooves 208. In certain embodiments, several ports 210 can be disposed between each pair of adjacent grooves 208. As shown in FIG. 23, several ports 210 are disposed circumferentially on the surface 180 on the grooves 208. 23, the number of ports 210 are disposed in some of the plurality of grooves 208. In certain embodiments, the number of ports 210 may be disposed in each of the number of grooves 208. The number of ports 210 operate functionally similar to the ports 194 described above. The grooves 208 and the ports 210 together function as a hybrid hydrodynamic bearing system.

[0045] 24 is a side view of an end cover 30 of a rotatable PX 20 having both a dynamic pressure generating feature 152 and a hydrostatic pressure enhancing feature 184 (e.g., herringbone groove and ports) according to one embodiment. As shown, the dynamic pressure generating feature 152 comprises a herringbone groove 216 disposed on the surface 186 of the end cover 30 radially between the groove 192 and the openings 188, 190. Structurally, the groove 216 comprises a central portion 218 and bifurcated portions 220 similar to the groove 202 of FIG. 21. Additionally, the groove 216 functions similarly to the groove 202 of FIG. 21. As shown, the hydrostatic pressure enhancing feature 184 comprises a number of ports 222 disposed on the groove 216. In particular, the number of ports 222 are disposed on the central portion 218 between the number of Y-shaped portions. As shown, the number of ports 222 are disposed between some of the adjacent Y-shaped portions of the groove 216. In certain embodiments, the number of ports 222 may be disposed between each pair of adjacent Y-shaped portions of the groove 216. The number and shape of the ports 222 can vary. The number of ports 222 function similarly to the ports 194 of FIGS. 12-14. The ports 222 and the groove 216 act together to function as a hybrid hydrodynamic-hydrostatic bearing system.

[0046] FIG. 25 is a side view of the end cover 30 of the rotary PX 20 having both the dynamic pressure generating mechanism 152 and the hydrostatic pressure enhancing mechanism 184 (e.g., V-shaped grooves and ports) of one embodiment. As shown, the dynamic pressure generating mechanism 152 comprises a plurality of grooves 224 (e.g., V-shaped grooves) disposed on the surface 186 of the end cover 30 between the grooves 192 and the openings 188, 190 in a radial direction. Furthermore, some of the grooves 224 are circumferentially aligned with each other. Each groove 224 comprises a pair of branches 226 that converge on a central portion 228. The purpose of the two branches of the "V" shape is similar to that in FIG. 24; that is, to provide "two-way" tilt and ND2 vibration correction. However, in this case, a central circumferential channel connecting all the individual grooves is not included. The reason for this is that certain applications that require minimal leakage flow through the bearing membrane would still benefit from the bi-directional tilt compensation mechanism while the absence of the central deeper circumferential channel would help reduce leakage. As shown, the hydrostatic enhancement mechanism 184 includes a number of ports 230 located between each pair of adjacent grooves 224. The number of ports 230 are circumferentially aligned with the central portions of the number of grooves 224. The number and shape of the ports 230 can vary. The ports 230 function similarly to the ports 194 of FIGS. 12-14. The ports 230 and the grooves 224 act together to function as a hybrid hydrodynamic hydrostatic bearing system.

[0047] 26 and 27 are side and perspective views, respectively, of an end cover 30 of a rotary PX 30 having both a dynamic pressure generating feature 152 and a hydrostatic pressure enhancing feature 184 (e.g., tapered lands, ports, pockets) of one embodiment. FIG. 28 is a cross-sectional view of the end cover 30 taken along line 28-28 in FIG. 26. The dynamic pressure generating feature 152 includes a number of tapered lands 232 radially disposed between the grooves 192 and the openings 188, 190. The hydrostatic pressure enhancing feature 184 includes pockets 234 and ports 236 disposed within the pockets 234 disposed on a plateau or flat region 238 adjacent to each of the tapered lands 232. In certain embodiments, the flat region 238 includes only ports 236 (i.e., no pockets 234). The pockets 234 and ports 236 function as described in FIG. 14. The depth, shape, and size of the pockets 234 can vary. The shape, number, and location of the ports 236 can vary. A plurality of pairs of tapered lands 232 and flat regions 238 are circumferentially arranged in an annular arrangement and aligned about the longitudinal axis 74. As shown in FIG. 28, the tapered lands 232 rise along the circumferential direction 148 from a circumferential position θ0 to θ1 adjacent the flat region 238 (e.g., in the direction 32). As shown, the length of the tapered lands 232 is greater than the length of the flat region 238. The movement of a flat surface (e.g., the end face 150 of the rotor 44) on the tapered lands 232 draws fluid into the converging wedge-shaped zone 240 using what is called a "squeeze action," which creates a higher pressure in the wedge than the fluid surrounding the wedge. As rotor 44 pushes the fluid across plateau region 238, the pressure inside the fluid film remains constant at this elevated value. Ports 236 generate hydrostatic pressure to not only supplement the pressure in plateau region 238, but also to provide a source of fluid in the plateau region if the gaps in the plateau region are completely closed where the film cannot enter. Thus, ports 236 (and / or pockets 234) and tapered lands 232 act together to function as a hybrid hydrodynamic-hydrostatic bearing system.The performance of the hybrid tapered land hydrostatic bearing can be optimized through adjustment of the angle of the tapered land 232, the maximum and minimum depth of the tapered region, the location of the hydrostatic ports 236, and the size of the hydrostatic pockets 234.

[0048] While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are herein described in detail. It will be understood, however, that the invention is not intended to be limited to the specific forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. The present disclosure also includes the following inventions. The first aspect is 1. A system comprising: a hydraulic energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end face and a second end face disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; and a hybrid hydrodynamic / hydrostatic bearing system configured to resist axial displacement of the cylindrical rotor. The second aspect is The system of a first aspect, wherein the fluid pressure energy transmission system comprises a rotary pressure exchanger. The third aspect is The hybrid hydrodynamic and hydrostatic bearing system of the first aspect includes a hydrostatic enhancement disposed on the first surface of the first end cover. The fourth aspect is A system according to a third aspect, wherein the hydrostatic pressure enhancement mechanism disposed on the first surface of the first end cover comprises a first plurality of ports circumferentially spaced apart relative to a longitudinal axis of the cylindrical rotor. The fifth aspect is A fourth aspect of the system, wherein the hydrostatic pressure enhancement mechanism disposed on the first surface of the first end cover includes a second plurality of ports circumferentially spaced apart relative to the longitudinal axis, the second plurality of ports being located radially inward of the first plurality of ports relative to the longitudinal axis. The sixth aspect is A fifth aspect of the system, wherein the first plurality of ports and the second plurality of ports are coupled to a plurality of channels disposed within the first end cover to form a hydrostatic channel network. The seventh aspect is A system in a sixth aspect, wherein each channel of the plurality of channels has a first portion extending axially relative to the longitudinal axis and a second portion extending radially relative to the longitudinal axis, the second portion being connected to an inlet configured to receive high-pressure fluid, and the first portion being connected to a respective port of either the first plurality of ports or the second plurality of ports configured to discharge the high-pressure fluid. The eighth aspect is 10. The system of claim 7, wherein a diameter of the second portion is greater than a diameter of the first portion. The ninth aspect is The system of a sixth aspect, wherein the hydrostatic pressure enhancement mechanism comprises an orifice flow restrictor disposed in at least one of the plurality of channels. A tenth aspect is A system in a fifth aspect, wherein the hydrostatic pressure enhancement mechanism comprises a plurality of recesses disposed on the first surface of the first end cover, and each port of either the first plurality of ports or the second plurality of ports is disposed within a respective recess of the plurality of recesses. An eleventh aspect is The hybrid hydrodynamic bearing system of a fourth aspect includes a hydrodynamic pressure generating mechanism disposed on the first surface of the first end cover. A twelfth aspect is A system in accordance with an eleventh aspect, wherein the dynamic pressure generating mechanism disposed on the first surface of the first end cover comprises a herringbone shaped groove extending circumferentially around the longitudinal axis, and the first plurality of ports are disposed within the herringbone shaped groove. A thirteenth aspect is A system in accordance with an eleventh aspect, wherein the dynamic pressure generating mechanism disposed on a surface disposed on the first surface of the first end cover has a plurality of grooves spaced circumferentially about the longitudinal axis, and each port of the first plurality of ports is disposed between an adjacent pair of grooves of the plurality of grooves. A fourteenth aspect is 13. The system of claim 12, wherein each groove of the plurality of grooves comprises a V-shape or a spiral shape. The fifteenth aspect is A system in accordance with an eleventh aspect, wherein the dynamic pressure generating mechanism disposed on the first surface of the first end cover comprises a plurality of tapered lands spaced circumferentially about the longitudinal axis, and each port of the first plurality of ports is disposed on a respective one of the plurality of tapered lands. A sixteenth aspect is The hybrid hydrodynamic and hydrostatic bearing system is a system in a first aspect comprising a number of hydrodynamic pressure generating features disposed on the first end face of the cylindrical rotor and a number of hydrostatic pressure enhancing features disposed on the first surface of the first end cover. A seventeenth aspect is A system in accordance with a sixteenth aspect, wherein the dynamic pressure generating mechanism disposed on the first end face includes a first plurality of grooves spaced circumferentially relative to the longitudinal axis of the cylindrical rotor adjacent to the outer diameter of the cylindrical rotor. The eighteenth aspect is A system in accordance with a seventeenth aspect, wherein the dynamic pressure generating mechanism disposed on the first end face includes a second plurality of grooves spaced circumferentially about the longitudinal axis adjacent to the inner diameter of the cylindrical rotor. A nineteenth aspect is 17. The system of claim 16, wherein each groove of the first plurality of grooves has a spiral shape. The twentieth aspect is A system in accordance with a sixteenth aspect, wherein the dynamic pressure generating mechanism disposed on the first end face comprises a herringbone shaped groove extending around the longitudinal axis of the cylindrical rotor adjacent to the outer diameter of the cylindrical rotor. A twenty-first aspect is A system in accordance with a sixteenth aspect, wherein the hydrostatic pressure enhancement mechanism disposed on the first surface of the first end cover comprises a first plurality of ports circumferentially spaced apart relative to a longitudinal axis of the cylindrical rotor. A twenty-second aspect is A system in accordance with a twenty-first aspect, wherein the hydrostatic pressure enhancement mechanism disposed on the first surface of the first end cover includes a second plurality of ports circumferentially spaced apart relative to the longitudinal axis, the second plurality of ports being located radially inward of the first plurality of ports relative to the longitudinal axis. A twenty-third aspect is A twenty-second aspect of the system, wherein the first plurality of ports and the second plurality of ports are coupled to a plurality of channels disposed within the first end cover to form a hydrostatic channel network. A twenty-fourth aspect is 23. The system of claim 22, wherein the hydrostatic pressure enhancement mechanism comprises an orifice flow restrictor disposed in at least one of the plurality of channels. The twenty-fifth aspect is A system in accordance with a twenty-first aspect, wherein the hydrostatic pressure enhancement mechanism comprises a plurality of recesses disposed on the first surface of the first end cover, and each port of either the first plurality of ports or the second plurality of ports is disposed within a respective recess of the plurality of recesses. A twenty-sixth aspect is 1. A system comprising: a hydraulic energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end face and a second end face disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; a hybrid hydrodynamic and hydrostatic bearing system configured to resist axial displacement of the cylindrical rotor; the hybrid hydrodynamic-hydrostatic bearing system comprising a hydrodynamic pressure generating mechanism disposed on the first end face of the cylindrical rotor and a hydrostatic pressure enhancing mechanism disposed on the first surface of the first end cover; The dynamic pressure generating mechanism comprises one or more grooves disposed on the first end face, and the hydrostatic pressure enhancing mechanism comprises a plurality of ports. A twenty-seventh aspect is 1. A system comprising: a hydraulic energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end face and a second end face disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; a hybrid hydrodynamic and hydrostatic bearing system configured to resist axial displacement of the cylindrical rotor; The hybrid hydrodynamic and hydrostatic bearing system is a system that includes both a number of hydrodynamic pressure generating features disposed on the first surface of the first end cover and a number of hydrostatic pressure enhancing features disposed on the first surface of the first end cover.

Claims

1. 1. A hydraulic energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, comprising: The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end surface and a second end surface disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; 13. A hybrid hydrodynamic bearing system configured to resist axial displacement of the cylindrical rotor, the hybrid hydrodynamic bearing system comprising: a hydrostatic pressure enhancement mechanism and a hydrodynamic pressure generating mechanism disposed on the first surface of the first end cover, the hydrostatic pressure enhancement mechanism disposed on the first surface of the first end cover comprising a first plurality of ports circumferentially spaced apart relative to a longitudinal axis of the cylindrical rotor, the hydrostatic pressure generating mechanism disposed on the first surface of the first end cover comprising a plurality of grooves circumferentially spaced apart relative to the longitudinal axis, the first plurality of ports being circumferentially aligned with the plurality of grooves relative to the longitudinal axis of the cylindrical rotor, each port of the first plurality of ports being disposed between an adjacent pair of the plurality of grooves, and the first end cover further comprising an inlet duct and an outlet duct radially spaced apart from the hybrid hydrodynamic bearing system.

2. The system of claim 1 , wherein the fluid pressure energy transmission system comprises a rotary pressure exchanger.

3. 2. The system of claim 1, wherein the hydrostatic intensifier disposed on the first surface of the first end cover comprises a second plurality of ports circumferentially spaced apart relative to the longitudinal axis, the second plurality of ports being located radially inward of the first plurality of ports relative to the longitudinal axis.

4. The system of claim 3 , wherein the first plurality of ports and the second plurality of ports are coupled to a plurality of channels disposed within the first end cover to form a hydrostatic channel network.

5. 5. The system of claim 4, wherein each channel of the plurality of channels comprises a first portion extending axially relative to the longitudinal axis and a second portion extending radially relative to the longitudinal axis, the second portion being connected to the inlet duct configured to receive high pressure fluid, and the first portion being connected to a respective port of either the first plurality of ports or the second plurality of ports configured to discharge the high pressure fluid.

6. The system of claim 5 , wherein the diameter of the second portion is greater than the diameter of the first portion.

7. The system of claim 4 , wherein the hydrostatic pressure enhancement mechanism comprises an orifice flow restrictor disposed in at least one of the plurality of channels.

8. 4. The system of claim 3, wherein the hydrostatic enhancement mechanism comprises a plurality of recesses disposed on the first surface of the first end cover, each port of either the first plurality of ports or the second plurality of ports being disposed within a respective one of the plurality of recesses.

9. 2. The system of claim 1, wherein the dynamic pressure generating mechanism disposed on the first surface of the first end cover comprises a herringbone shaped groove extending circumferentially about the longitudinal axis, the first plurality of ports being disposed within the herringbone shaped groove.

10. The system of claim 1 , wherein each groove of the plurality of grooves comprises a V-shape or a spiral shape.

11. A system comprising a fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid has a pressure greater than a pressure of the second fluid; The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end surface and a second end surface disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; 13. A hybrid hydrodynamic hydrostatic bearing system configured to resist axial displacement of the cylindrical rotor, the hybrid hydrodynamic hydrostatic bearing system comprising: a hydrostatic pressure generating mechanism disposed on the first end face of the cylindrical rotor; and a hydrostatic pressure enhancing mechanism disposed on the first surface of the first end cover, the hydrostatic pressure enhancing mechanism comprising one or more grooves disposed on the first end face of the cylindrical rotor, the hydrostatic pressure enhancing mechanism comprising a first plurality of ports, the hydrostatic pressure generating mechanism disposed on the first end face comprising a first plurality of grooves circumferentially spaced relative to a longitudinal axis of the cylindrical rotor adjacent an outer diameter of the cylindrical rotor, the hydrostatic pressure generating mechanism disposed on the first end face comprising a second plurality of grooves circumferentially spaced relative to a longitudinal axis of the cylindrical rotor adjacent an inner diameter of the cylindrical rotor, the rotor further comprising a plurality of channels radially spaced from the second plurality of grooves.

12. The system of claim 11 , wherein each groove of the first plurality of grooves has a spiral shape.

13. 12. The system of claim 11, wherein the dynamic pressure generating feature disposed on the first end face comprises a herringbone groove extending around the longitudinal axis of the cylindrical rotor adjacent an outer diameter of the cylindrical rotor.

14. 12. The system of claim 11, wherein the hydrostatic intensifier disposed on the first surface of the first end cover comprises a second plurality of ports circumferentially spaced apart relative to the longitudinal axis, the second plurality of ports being radially inward of the first plurality of ports relative to the longitudinal axis.

15. 15. The system of claim 14, wherein the first plurality of ports and the second plurality of ports are coupled to a plurality of channels disposed within the first end cover to form a hydrostatic channel network.

16. The system of claim 15 , wherein the hydrostatic pressure enhancement mechanism comprises an orifice flow restrictor disposed in at least one of the plurality of channels.

17. 12. The system of claim 11, wherein the hydrostatic enhancement mechanism comprises a plurality of recesses disposed on the first surface of the first end cover, each port of either the first plurality of ports or the second plurality of ports being disposed within a respective one of the plurality of recesses.

18. 1. A fluid pressure energy transmission system configured to exchange pressure between a first fluid and a second fluid, the first fluid having a higher pressure than the second fluid, comprising: The fluid pressure energy transmission system comprises: a cylindrical rotor configured to rotate circumferentially about a rotation axis, the cylindrical rotor having a first end face and a second end face disposed opposite each other; a first end cover having a first surface that interfaces with the first end surface of the cylindrical rotor; a hybrid hydrodynamic and hydrostatic bearing system configured to resist axial displacement of the cylindrical rotor; the hybrid hydrodynamic-hydrostatic bearing system comprising both a number of hydrodynamic pressure generating features disposed on the first surface of the first end cover and a number of hydrostatic pressure enhancing features disposed on the first surface of the first end cover; a number of the hydrostatic intensification features disposed on the first surface of the first end cover comprising a first plurality of ports spaced circumferentially relative to a longitudinal axis of the cylindrical rotor, the dynamic pressure generating features comprising a plurality of grooves, a number of the dynamic pressure generating features disposed on the first surface of the first end cover comprising a plurality of tapered lands spaced circumferentially relative to a longitudinal axis of the cylindrical rotor, the first plurality of ports being circumferentially aligned with the plurality of grooves relative to the longitudinal axis of the cylindrical rotor, each port of the first plurality of ports being disposed between an adjacent pair of tapered lands of the plurality of tapered lands, each tapered land rising circumferentially relative to the longitudinal axis toward and continuous with a respective flat region, and each port being disposed on each flat region.

Images