Patent Application
20230065642
The present disclosure relates generally to pumps. More particularly, the present disclosure relates to electric pumps having components cooled by working fluid of the pumps.
Electric pumps include a housing defining an inlet and an outlet. A rotor and a stator are mounted in the housing. The stator surrounds the rotor. The rotor includes a shaft coupled to an impeller for moving working fluid through the housing in a direction from the inlet to the outlet. The housing can be configured such that the working fluid contacts the rotor and the stator to provide cooling of the rotor and the stator.
The present disclosure relates to an electric pump including a housing defining an inlet and an outlet. The electric pump includes a rotor and stator within the housing. The rotor is liquid cooled by working fluid of the pump and the stator is positioned in a dry chamber that is sealed to prevent the working fluid from entering the dry chamber. A heat exchanger is used to cool the stator. An impeller driven by the rotor draws working fluid into the housing through the inlet. The working fluid passes through the heat exchanger to draw heat from the stator before reaching the impeller. At the impeller, the working fluid is pressurized and forced toward the outlet where the working fluid is discharged from the pump. In one example, an isolation sleeve surrounding the rotor is used to isolate the stator from the working fluid that cools (e.g., bathes) the rotor. In one example, the isolation chamber also prevents the working fluid from applying pressure to the stator. In one example, the impeller is a centrifugal impeller surrounded by a volute passage. In one example, the isolation tube is sealed relative to the housing by seals such as radial seals positioned adjacent to opposite ends of the isolation tube.
A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples disclosed herein are based.
The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:
Certain aspects of the present disclosure relate to electric pumps having rotor assemblies that are cooled by working fluid and stators that are isolated from the working fluid. In certain examples, it can be beneficial to isolate the stator from the working fluid to prevent the stator from being exposed to relatively high hydraulic pressures associated with the working fluid. For example, a pump adapted to convey a working fluid such as supercritical carbon dioxide often is rated to accommodate pump inlet pressures greater than or equal to 2000 pounds per inch (psi), or greater than or equal to 2250 psi or greater than or equal to 2500 psi. In certain applications and with certain types of stators, such relatively high pressures may cause damage to portions of the stators (e.g., windings of the stators) if the stators are exposed to such pressures.
Referring to
It will be appreciated that the rotor assembly 34 and the stator assembly 40 are configured to function as an electric motor with the rotor assembly 34 being the rotational part of the electric motor and the stator assembly 40 being the non-rotational part of the electric motor. In certain examples, the stator assembly 40 generates magnetic fields which drive rotation of the rotor assembly 34. It will be appreciated that the rotor assembly 34 and/or the stator assembly 40 can include complements such as wire windings (e.g., copper wire windings), magnets or other components typically used in electric motors.
The electric pump 20 is preferably configured such that the working fluid is allowed to enter the rotor chamber 28 to bathe and cool the rotor assembly 34. As indicated above, the isolation sleeve 32 is configured to prevent the working fluid from entering the stator chamber 30. In one example, the isolation sleeve 32 is sealed relative to the housing 22 such that the housing and the isolation sleeve 32 cooperates to prevent working fluid from flowing from the rotor chamber 28 to the stator chamber 30.
Rather than being cooled by direct contact with the working fluid, the stator assembly 40 is preferably cooled by a heat exchanger 42 through which the working fluid flows. The heat exchanger 42 surrounds the stator assembly 40 and in certain examples contacts an outer diameter of the stator assembly 40. Working fluid flowing through the heat exchanger 42 draws heat from the stator assembly 40 to cool the stator assembly 40. In one example, the heat exchanger 42 has a metal construction and can be manufactured using an additive manufacturing process. By using an additive manufacturing process, an arrangement of fluid passages can be defined within the heat exchanger 42. The fluid passages are adapted to pass in close proximity to the stator assembly 40 to promote the effective transfer of heat from the stator assembly 40 to the working fluid flowing through the heat exchanger 42.
The electric pump 20 also includes an impeller 44 coupled to the rotor shaft 36 for drawing the working fluid from the inlet 24 through the heat exchanger 42 to an impeller chamber 46 in which the impeller 44 is mounted. The working fluid is pressurized within the impeller chamber 46 and directed toward the outlet 26 of the housing 22 such that the working fluid is discharged from the housing 22 through the outlet 26. In one example, the impeller 44 is a centrifugal impeller and a volute passage 48 is defined by the housing 22 around the impeller 44 (see
The rotor shaft 36 has a first end 52 and a second end 54 opposite to the first end. The first end 52 couples to the impeller 44 and is supported by a first bearing 56 coupled to the housing 22 that provide both radial and axial bearing functionality. In one example, the first bearing 56 is attached to the housing 22 so as to be axially fixed along the rotor axis 38. In one example, the first bearing 56 can be configured to support the rotor shaft 36 for rotation about the rotor axis 38 and in certain examples can be configured as a hydrodynamic bearing such that the rotor shaft 36 is fluidly supported within the bearing 56. The bearing 56 can be positioned between first and second spacers 58, 60 fixed on the rotor shaft 36. In this way, axial contact between the spacers 58, 60 and the bearing 56 limits or restricts axial movement of the rotor shaft 36 relative to the housing 22 along the rotor axis 38. The second end 54 of the rotor shaft 36 is supported by a second bearing 57 which can provide radial bearing functionality can include a hydrodynamic bearing. In one example, the second bearing 57 does not function as an axial bearing and the rotor shaft 36 can move axially relative to the radial bearing 57 to accommodate thermal expansion and contraction of the rotor shaft 36. In one example, the housing 22 can be configured such that pressure of the working fluid is allowed to act on opposite ends of the rotor shaft 36 to provide axial force balancing. In certain example, passages can be provided within the housing 22 to ensure the working fluid can flow to the regions adjacent the opposite axial ends of the rotor shaft 36.
In certain examples, the isolation sleeve 32 can have a composite construction. For example, the isolation sleeve 32 can include different portions having different material constructions. In one example, the isolation sleeve 32 can include an inner sleeve portion 64 having a metal construction (e.g., steel or aluminum) and an outer sleeve portion 66 mounted within a recess defined at an exterior of the inner sleeve portion 64. In one example, the outer sleeve portion 66 can include a construction that includes carbon fibers. The isolation sleeve 32 is preferably sealed relative to the housing 22. For example, sealing arrangements 39 can be provided adjacent opposite ends of the isolation sleeve 32. In one example, each of the sealing arrangements 39 can include a seal 70 (e.g., a gasket such as an o-ring or other type of seal) and a back-up ring 72 for preventing deformation/extrusion of the seal under pressure. In one example, the seals 70 are radial seals mounted within circumferential grooves defined about the circumference of the isolation sleeve 32 adjacent the ends of the isolation sleeve 32. The seals 70 preferably seal against corresponding sealing surfaces defined by the housing 22.
This application claims the benefit of provisional application Ser. No. 63/237,383, filed Aug. 26, 2021, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63237383 | Aug 2021 | US |
