SUBMERSIBLE PUMPING SYSTEMS AND METHODS FOR DEEP WELL APPLICATIONS
Submersible pumping systems, devices and methods for extracting liquids in deep well applications are disclosed. In the various embodiments, a submersible pumping system includes a power supply and a power converter coupled to the power supply. A subsurface unit may be coupled to the power converter and positioned in the well. The subsurface unit may include a subsurface controller, a motor and a pump portion operably coupled to the subsurface controller. The pump portion may further include a front shroud having an inlet, and a back shroud sealably coupled to the front shroud to define a volume. An orifice fluidly communicates with the volume and an annular fluid discharge space disposed about the subsurface unit. An impeller operably coupled to the motor and positioned within the volume may transport a liquid from the inlet to the annular fluid discharge space.
The present invention relates generally to fluid transfer devices and methods, and more particularly, to submersible pumping systems, devices and methods for extracting liquids in deep well applications.
BACKGROUNDSubmersible pumps are typically employed in sub-surface pumping applications where it is desired to remove liquids from relatively deep well locations. A centrifugal pump is typically employed in such applications, since it may be readily configured to provide a relatively high pumping head while providing a desired liquid flow rate at a surface location. Submersible centrifugal pumps of conventional design typically include a series of vertically stacked radial impellers in order to provide the desired lift from the well. The impeller stack is generally rotationally coupled to an electric motor that that may be located at the sub-surface location, and coupled to the centrifugal pump by a shaft that extends from the centrifugal pump to the motor.
Submersible pumps are also commonly used in well-sampling and monitoring applications. In such applications, however, the submersible pump must be suitably dimensioned to be removably positioned in a bore hole of relatively small diameter (e.g., approximately one to four inches in diameter), while providing acceptable performance over a wide range of well depths and flow rates. In selected instances, the submersible pump may be operated intermittently, so that the well is periodically sampled.
In the interest of reducing size, complexity and manufacturing costs, centrifugal pumps in well-sampling and monitoring applications generally employ a single impeller that is closely coupled to an electric motor that is positioned with a sealed enclosure. Accordingly, numerous difficulties are encountered in the design and operation of well-sampling and monitoring applications that are not present in larger multi-stage devices. For example, relatively long electrical lead lengths may introduce undesired transient electrical loading conditions that may adversely affect the motor, the power supply, or both.
Therefore, what is needed in the art are submersible pumping systems, apparatuses and methods that extracting liquids in deep well applications.
The various embodiments of the present invention are described in detail below with reference to the following drawings.
The present invention relates to submersible pumping systems, devices and methods for extraction of liquids in deep well applications. Many specific details of the various embodiments are set forth in the following description and in
The system 10 further includes a power supply 28 that is coupled to a power converter 30 that is, in turn, coupled by electrical leads 29 to the subsurface unit 12 to provide electrical energy to the unit 12. The power supply 28 may include any suitable alternating current (AC) or direct current (DC) source. For example, the power supply 28 may include a DC source, such as a storage battery, or an AC source, such as a conventional AC power distribution system. In other of the various embodiments, the power supply 28 may include an energy source that is suitable to supply either AC or DC power to the power converter 30 and the subsurface unit 12 when the system 10 is positioned at a remote location that disfavors the use of a storage batteries, and where conventional AC power is not available. For example, the power supply 28 may include an electrical generator that is coupled to a prime mover, such as an internal combustion engine, to provide either AC or DC power to the power converter 30. The power supply 28 may also include a wind turbine that is structured to generate rotational motion from atmospheric winds, and to impart the rotational motion to a generator that provides either AC or DC power. In still other of the various embodiments, the power supply 28 may include one or more photovoltaic panels that are structured to receive illumination (e.g., solar illumination) and convert the received illumination to an electrical current. In still other embodiments, power sources based upon electrochemical energy conversion may be used, such as a fuel cell, or other similar devices.
Still referring to
With reference now to
The power converter 50 may also include an indication unit 60 that is operable to measure the output voltage VDC, OUT, and to display the value on a visual display 62. In another of the various embodiments, the indication unit may be configured to measure a current value delivered to the output terminals 56. In still another of the various embodiments, the indication unit 60 may be configured to measure an electrical power value delivered to the output terminals 56. In another of the various embodiments, the indication unit 60 may be configured to display a liquid flow rate.
The AC-to-DC converter 74 may be coupled to a DC-to-DC converter 52, as previously described. When the input voltage VAC, IN includes one of a 120 v and a 208 v AC source, the DC-to-DC converter which may include a “buck” converter, so that the output voltage VDC, OUT is reduced to a suitable level. In other embodiments, a boost converter, or a buck-boost converter may also be used.
With reference now to
The motor 94 may be conductively coupled to a subsurface controller 98 by a conductive assembly 100 that is structured to be removably coupled to at least one of the motor 94 and the subsurface controller 98. The assembly 100 may accordingly include a plurality of parallel conductive components that are each configured to couple a single phase to the polyphase motor 94. The subsurface controller 98 may, in turn, be coupled to one of the power converter 50, as shown in
With reference now also to
The subsurface unit 130 further includes a generally cylindrical inner housing 144 that may be sealably coupled to the back shroud 136, which may also be sealably coupled to an end cap 146. Accordingly, the back shroud 136, the inner housing 144 and the end cap 146 may cooperatively form a hermetically-sealed volume 148 that contains the motor 94 and the subsurface controller 110. A generally cylindrical outer housing 150 may be sealably coupled to the front shroud 134 and to the end cap 146 to define a generally annular fluid discharge space 152 between the inner housing 144 and the outer housing 150. The fluid discharge space 152 fluidly communicates with a fluid passage 154 formed in the end cap 146, that may further fluidly communicate with the liquid discharge conduit 26 through a suitable end fitting 156. The end cap 146 may also include suitable electrical feedthroughs 158 that permit the subsurface controller 110 and the motor 94 to be electrically coupled to one of the converters 50 and 70, as shown in detail in
With reference now to
Referring now to
While the various embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the scope of this disclosure. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
Further, the accompanying drawings that form a part hereof show by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.
The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features may be grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
Claims
1. A submersible pumping system for a well, comprising:
- a power supply;
- a power converter coupled to the power supply; and
- a subsurface unit coupled to the power converter and configured to be positioned in the well remote from the power supply and the power converter, wherein the subsurface unit includes a subsurface controller, and a motor and a pump portion operably coupled to the subsurface controller, the pump portion further comprising:
- a front shroud having an inlet;
- a back shroud sealably coupled to the front shroud to define a volume there between;
- an orifice that fluidly communicates with the volume and an annular fluid discharge space at least partially disposed about the subsurface unit; and
- an impeller operably coupled to the motor and positioned within the volume to transport a liquid from the inlet to the annular fluid discharge space.
2. The system of claim 1, wherein the front shroud includes an axially disposed conical inner portion having a taper angle that ranges between approximately 45 degrees and approximately 60 degrees.
3. The system of claim 1, wherein the front shroud comprises a strainer fluidly coupled to the inlet that is configured to restrict the entry of solid material into the volume.
4. The system of claim 1, wherein the orifice comprises a constant diameter portion and a tapered portion coupled to the constant diameter portion, the tapered portion having an included angle that ranges between approximately five degrees, and approximately 50 degrees.
5. The system of claim 4, wherein the constant diameter portion comprises a diameter that ranges between approximately 0.030 inches, and approximately 0.120 inches.
6. The system of claim 1, wherein the impeller comprises a planar and circular disk that supports a plurality of outwardly extending vanes, and a centrally disposed impeller hub configured to be coupled to the motor.
7. The system of claim 6, wherein the disk comprises a plurality of apertures extending through the disk and positioned between the outwardly extending vanes.
8. The system of claim 6, wherein the outwardly extending vanes are spaced apart from the front shroud by a clearance distance that ranges between approximately 0.005 inch and approximately 0.040 inch.
9. The system of claim 6, wherein the outwardly extending vanes are inclined at an angle that ranges between approximately 45 degrees and approximately 60 degrees.
10. The system of claim 6, wherein the impeller hub is configured to fixedly retain a shaft extending from the motor using an interference fit.
11. The system of claim 1, wherein the motor comprises a polyphase, brushless and sensor less DC motor.
12. A submersible pumping system for a well, comprising:
- a power supply;
- a power converter coupled to the power supply; and
- a subsurface unit coupled to the power converter and configured to be positioned in the well remote from the power supply and the power converter, wherein the subsurface unit includes a pump portion and a motor operably coupled to the pump portion, and a subsurface controller, the subsurface controller further comprising:
- a power compensation circuit operable to receive electrical power from the power converter configured to reduce at least one of a reactance introduced by the motor and reactive and resistive effects introduced by electrical leads coupling the power converter to the subsurface unit;
- a motor controller coupled to the power compensation circuit that is configured to convert electrical power received from the power compensation circuit to polyphase electrical power that is communicated to the motor; and
- a motor speed controller configured to control a rotational speed of the motor when the polyphase electrical power is first applied to the motor.
13. The system of claim 12, wherein the power supply comprises one of an alternating current (AC) source and a direct current (DC) source.
14. The system of claim 13, wherein the DC source comprises one of a storage battery, one or more photovoltaic panels, and a fuel cell device.
15. The system of claim 13, wherein the power converter comprises a DC-to DC converter configured to receive a DC voltage at a first voltage level, and convert the DC voltage to a second voltage level.
16. The system of claim 15, wherein the DC-to-DC converter comprises one of a buck-boost converter, a boost converter and a buck converter.
17. The system of claim 15, wherein the DC-to-DC converter is coupled to an AC-to-DC converter that receives an AC voltage from the power supply, and converts the AC voltage to a DC voltage.
18. The system of claim 12, wherein the power compensation circuit comprises one or more capacitors operably coupled to the power converter and the motor controller.
19. The system of claim 12, wherein the motor controller comprises at least one inverter circuit configured to receive a DC voltage, and to convert the DC voltage to an AC voltage.
20. The system of claim 12, wherein the motor controller comprises a speed sensing circuit that is operable to sense a back electromotive force from the motor and to regulate a speed of the motor based upon the sensed electromotive force.
21. The system of claim 12, wherein the motor speed controller is configured to provide a motor speed distribution that is implemented during a time period that extends from a motor start value to a maximum speed value.
22. The system of claim 21, wherein the time period is approximately one to three seconds.
23. The system of claim 21, wherein the motor speed distribution extends linearly during the time period.
24. The system of claim 21, wherein the motor speed distribution comprises one of a second-degree speed distribution and a third-degree speed distribution.
25. A submersible pumping system for a well, comprising:
- a power supply;
- a feedback system coupled to the power supply; and
- a subsurface unit coupled to the feedback system and configured to be positioned in the well remote from the power supply and the feedback system, wherein the subsurface unit includes at least a pump portion and a motor operably coupled to the pump portion, the pump portion being operable to transport a volume of a liquid from the well to a flow meter, the feedback system further comprising:
- a control mode unit configured to implement a predetermined control mode;
- a power converter coupled to the control mode unit that is configured to receive electrical power from the power supply, and to controllably provide electrical power to the subsurface unit based upon an out\put from the control mode unit; and
- a comparator that receives a feedback signal from the flow meter that provides an error signal to the control mode unit based upon a comparison of the feedback signal and a desired flow value.
26. The system of claim 25, wherein the control mode unit is configured to implement one of a proportional (P) control mode, a derivative (D) control mode, a proportional-derivative (P-D) control mode, an integral (I) control mode, a proportional-integral (P-I) control mode, and a proportional-integral-derivative (P-I-D) control mode.
27. The system of claim 25, wherein the power converter comprises a DC-to DC converter configured to receive a DC voltage at a first voltage level, and convert the DC voltage to a second voltage level.
28. The system of claim 27, wherein the DC-to-DC converter comprises one of a buck-boost converter, a boost converter and a buck converter.
29. The system of claim 25, wherein the DC-to-DC converter is coupled to an AC-to-DC converter that receives an AC voltage from the power supply, and converts the AC voltage to a DC voltage.
30. The system of claim 29, wherein the AC-to-DC converter comprises a rectifier circuit.
31. A method of removing a liquid from a well, comprising:
- positioning a subsurface unit into a well, the subsurface unit including at least a pump portion coupled to a motor configured to impart a rotational motion to the pump portion;
- coupling the subsurface unit to a power supply and a power converter configured to controllably provide electrical power to the subsurface unit; and
- starting the motor using a selected motor speed distribution.
32. The method of claim 31, wherein starting the motor using a selected motor speed distribution comprises implementing the motor speed distribution over a time period that ranges between approximately one to three seconds.
33. The method of claim 31, wherein starting the motor using a selected motor speed distribution comprises a linear motor speed distribution.
34. The method of claim 31, wherein starting the motor using a selected motor speed distribution comprises a parabolic motor speed distribution.
35. The method of claim 31, wherein starting the motor using a selected motor speed distribution comprises a motor speed distribution conforming to a third-order polynomial.
36. The method of claim 31, further comprising:
- setting a desired speed for steady-state motor operation;
- detecting a variation in the steady-state motor operation by sensing a back electromotive force from the motor; and
- correcting at least one of a voltage and a current delivered to the motor to return the motor to the desired speed.
37. The method of claim 36, wherein setting a desired speed for steady-state motor operation comprises providing a control input to the power converter.
38. A method of removing a liquid from a well, comprising:
- positioning a subsurface unit into a well, the subsurface unit including at least a pump portion and a motor coupled to the pump portion, the subsurface unit being configured to transport a liquid from the well to a surface location;
- coupling the subsurface unit to a power supply and a feedback system configured to controllably provide electrical power to the subsurface unit;
- selecting a desired flow rate to be delivered by the subsurface unit;
- setting a speed for the motor that delivers the desired flow rate;
- measuring a delivered flow rate; and
- if the delivered flow rate differs from the desired flow rate, then correcting the speed to attain the desired flow rate.
Type: Application
Filed: May 16, 2007
Publication Date: Nov 20, 2008
Inventors: Steven Regalado (Westminster, CO), Joseph L. Leonard (Arvada, CO)
Application Number: 11/749,600
International Classification: F04B 23/14 (20060101);