Abstract
Non-limiting exemplary embodiments of a pumping system and methods for operating the pumping system in a region of high pressure or a region of high flow are disclosed. The pumping system includes a piston disposed within a piston cylinder, a drive shaft, an eccentric coupled to the drive shaft, a connecting arm having opposing first and second ends, and a controller for controlling the rotation of the drive shaft such that the piston oscillates within a region of high pressure or a region of high flow.
Claims
1. A pumping system comprising: an electric motor; a piston disposed within a piston cylinder; a drive shaft configured to be rotatably driven by the electric motor; a connecting arm; an eccentric connected between the drive shaft and the connecting arm, wherein the eccentric and the connecting arm convert rotation of the drive shaft into linear reciprocation of the piston within the piston cylinder; and a controller communicatively coupled to the electric motor; wherein the controller is configured to operate the electric motor in a first mode and a second mode; wherein in the first mode the controller causes the electric motor to rotate the drive shaft through a series of full rotations in which the drive shaft rotates continuously in a first rotational direction to cause a first series of stroke cycles of the piston, each stroke cycle of the first series of stroke cycles comprising one upstroke and one downstroke of the piston; and wherein in the second mode the controller causes the electric motor to oscillate the drive shaft in a series of arc cycles corresponding to a second series of stroke cycles of the piston, each arc cycle of the series of arc cycles comprises the drive shaft rotating through a first arc in the first rotational direction less than one full rotation and through a second arc in a second rotational direction less than one full rotation, each stroke cycle of the second series of stroke cycles comprising one upstroke and one downstroke of the piston, and wherein each stroke cycle of the first series of stroke cycles causes greater displacement of the piston than each stroke cycle of the second series of stroke cycles.
2. The pumping system of claim 1, wherein in the second mode the controller causes the drive shaft to oscillate back and forth within a region, causing the piston to complete a partial upstroke and a partial downstroke within the piston cylinder.
3. The pumping system of claim 2, wherein the region is one of a first high pressure region, a second high pressure region, a first high flow region, and a second high flow region.
4. The pumping system of claim 3, wherein: the first high pressure region corresponds to an oscillation of the eccentric about a 12 o'clock position; the second high pressure region corresponds to the oscillation of the eccentric about a 6 o'clock position; the first high flow region corresponds to the oscillation of the eccentric about a 3 o'clock position; and the second high flow region corresponds to the oscillation of the eccentric about a 9 o'clock position.
5. The pumping system of claim 2, wherein in the second mode the controller causes the drive shaft rotate through a first pre-determined angular rotation in the first rotational direction and rotate through a second pre-determined angular rotation in the second rotational direction.
6. The pumping system of claim 1, wherein the controller is configured to cause the electric motor to switch the electric motor from the first mode to the second mode; and wherein the controller is configured to cause the electric motor to switch the electric motor from the second mode to the first mode.
7. The pumping system of claim 1, wherein oscillating the drive shaft comprises: increasing a speed of the drive shaft in the first rotational direction until the speed reaches a first speed; decreasing the speed of the drive shaft in the first rotational direction until the drive shaft stops rotation in the first rotational direction; and increasing the speed of the drive shaft in the second rotational direction until the speed reaches the first speed.
8. The pumping system of claim 7, wherein in the second mode the controller is configured to: increase a torque of the drive shaft in the first rotational direction until the torque reaches a peak value; decrease the torque of the drive shaft in the first rotational direction until the drive shaft stops rotation in the first rotational direction; and increase the torque of the drive shaft in the second rotational direction until the torque reaches the peak value, wherein the peak value of the torque is less than a maximum torque threshold.
9. The pumping system of claim 1, wherein the controller operates the electric motor in the first mode or the second mode based on a fluid pressure set-point or a fluid flow set-point.
10. The pumping system of claim 1, wherein the controller operates the electric motor in the first mode or the second mode based on one or more of a speed of the electric motor, a torque of the electric motor, electric current supplied to the electric motor, and a position of the drive shaft.
11. The pumping system of claim 1 and further comprising an intermediate drive, wherein the intermediate drive is positioned between the electric motor and the drive shaft, and wherein the intermediate drive is coupled to both the electric motor and the drive shaft such that the intermediate drive receives input rotation from the electric motor and the intermediate drive outputs rotation to the drive shaft.
12. A method of operating a pumping system including a piston disposed within a piston cylinder, a drive shaft rotatably driven by an electric motor, an eccentric connected between the drive shaft and a connecting arm, the eccentric and the connecting arm configured to convert rotation of the drive shaft into linear reciprocation of the piston within the piston cylinder, and a controller communicatively coupled to the electric motor, the method comprising: causing, by the controller, the electric motor to operate in a first mode in which the electric motor rotates the drive shaft through a series of full rotations in which the drive shaft rotates continuously in a first rotational direction to cause a first series of stroke cycles of the piston, each stroke cycle of the first series of stroke cycles comprising one upstroke and one downstroke of the piston; and causing, by the controller, the electric motor to operate in a second mode in which the electric motor oscillates the drive shaft in a series of arc cycles corresponding to a second series of stroke cycles of the piston, each arc cycle of the series of arc cycles comprises the drive shaft rotating through a first arc in the first rotational direction less than one full rotation and through a second arc in a second rotational direction less than one full rotation, each stroke cycle of the second series of stroke cycles comprising one upstroke and one downstroke of the piston; wherein each stroke cycle of the first series of stroke cycles causes greater displacement of the piston than each stroke cycle of the second series of stroke cycles.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a cross-sectional view of a non-limiting exemplary embodiment of a pumping system of the instant disclosure;
(2) FIG. 2A illustrates the operation of the pump of FIG. 1;
(3) FIG. 2B illustrates the linear position of the piston and the corresponding relative mechanical advantage of the pump of FIG. 2A during one rotation of the drive shaft;
(4) FIG. 3A illustrates an exemplary operation of the pump in a high pressure region;
(5) FIG. 3B illustrates exemplary linear positions of the piston and the corresponding relative mechanical advantage for the pump of FIG. 3A;
(6) FIG. 4A illustrates an exemplary operation of the pump in another high pressure region;
(7) FIG. 4B illustrates exemplary linear positions of the piston and the corresponding relative mechanical advantage for the pump of FIG. 4A;
(8) FIG. 5A illustrates an exemplary operation of the pump in a high flow region;
(9) FIG. 5B illustrates exemplary linear positions of the piston and the corresponding relative mechanical advantage for the pump of FIG. 5A;
(10) FIG. 6A illustrates an exemplary operation of the pump in another high flow region;
(11) FIG. 6B illustrates exemplary linear positions of the piston and the corresponding relative mechanical advantage for the pump of FIG. 6A;
(12) FIG. 7 is a cross-sectional view of a non-limiting exemplary embodiment of a pump having a ball valve;
(13) FIG. 8 is a flow chart of a non-limiting exemplary embodiment of a method of operating the pump of the instant disclosure in the high pressure regions illustrated in FIGS. 3 and 4;
(14) FIG. 9 is a flow chart of a non-limiting exemplary embodiment of a method of operating the pump of the instant disclosure in the high flow regions illustrated in FIGS. 5 and 6; and
(15) FIG. 10 is a block diagram of a non-limiting exemplary embodiment of a control loop for operating the pump in the high pressure and the high flow regions.
DETAILED DESCRIPTION
(16) One or more non-limiting embodiments are described herein with reference to the accompanying drawings, wherein like numerals designate like elements. It should be clearly understood that there is no intent, implied or otherwise, to limit the disclosure in any way, shape or form to the embodiments illustrated and described herein. While multiple exemplary embodiments are provided, variations thereof will become apparent or obvious to a person of ordinary skills. Accordingly, any and all variants for providing functionalities similar to those described herein are considered as being within the metes and bounds of the instant disclosure.
(17) FIG. 1 is a cross-sectional view of a non-limiting exemplary embodiment of a pumping system (or pump) 10 of the instant disclosure. In certain embodiments, the pumping system 10 includes a piston 110 disposed within a piston cylinder 130, a drive shaft 150 driven by a motor 180, and a controller 170. The motor 180 can be, but is not limited to, an air motor powered by compressed air or an electric motor powered by alternating current. In some embodiments, the controller 170 controls the output (e.g., rotational direction, rotational speed, etc.) of the drive shaft 150 by controlling the direction and/or speed of the motor 180. In certain embodiments, the controller 170 accepts AC or DC voltage as an input power source and outputs AC or DC voltage to control the motor 180. In some embodiments, the controller 170 is configured to measure the motor current, and measure or estimate the motor position and speed using components and/or methods well known in the art including, but not limited to, sensor-less control algorithms, encoders, feedback loops, hall sensors, among others.
(18) In a non-limiting exemplary embodiment, the pumping system 10 includes a drive section defined at least in part by the drive shaft 150 and the eccentric 160 (e.g., crank arm, scotch yoke, etc.). Generally, the drive section is configured to drive or operate the piston 110. In some embodiments, a connecting arm 120 connects the pump section and the drive section to each other. In certain embodiments, the connecting arm 120 and the piston 110 are connected at connection point 122. The opposite end of the connecting arm 120 connects to the eccentric 160 at connection point 124.
(19) In a non-limiting exemplary embodiment, the pumping system 10 includes an intermediate drive 190 (e.g., gear drive, transmission, clutch, etc.) as is well known in the art. In some embodiments, the intermediate drive 190 is located between the motor 180 and the drive shaft 150. In certain embodiments, the controller 170 may control the output (e.g., direction, speed, gearing, etc.) of the intermediate drive 190 in order to control the rotation of the drive shaft 150. The motor 180 or intermediate drive 190 may be referred to generically as an actuator, to the extent they drive the drive shaft 150. In some embodiments, control of the intermediate drive 190 by the controller 170 may be in addition to the control of the motor 180. Alternatively, the controller 170 may only control the output of the drive shaft 150 via control of the intermediate drive 190. In certain embodiments, the controller 170 is configured to ascertain the position of the drive shaft 150 from various methods known in the art including, but not limited to, sensor-less control algorithms, clocking signals from an external position sensor, etc.
(20) FIG. 2A illustrates the operation of the pumping system 10. The motor (not shown) rotates the drive shaft 150 continuously in the same direction, for example as indicated by the arrows 12. One complete revolution of the drive shaft 150 results in one upstroke and one downstroke of the piston 110, and the revolutions are repeated to continue operation of the pumping system 10. Each stroke of the piston 110 performs work either pumping material out of the cylinder 130 or filling the cylinder 130 with material. FIG. 2B illustrates the linear position 16 of the piston 110 within the piston cylinder 130 and the corresponding relative mechanical advantage 14 of the pumping system 10 during one complete revolution of the drive shaft 150. The distance L.sub.E represents the stroke or the displacement of the piston 110 within the piston cylinder 130 during one complete revolution of the drive shaft 150. Peak or maximum torque and maximum motor current draw occurs when the rate of displacement of the piston 110 with respect to the rate of change of the rotation angle of the eccentric 160 (and the drive shaft 150) is approximately maximum or greatest. Nominally, this occurs at approximately the 3 o'clock and 9 o'clock positions of the eccentric 160 (and the drive shaft 150). The corresponding relative mechanical advantage 14 of the pumping system 10 is approximately minimum at these positions, and the flow rate of the material through the pumping system 10 is substantially consistent. Similarly, minimum torque and minimum current draw occurs when the rate of displacement of the piston 110 with respect to the rate of change of the rotation angle of the eccentric 160 (and the drive shaft 150) is approximately minimum. Nominally, this occurs at approximately the 12 o'clock and 6 o'clock positions of the eccentric 160 (and the drive shaft 150). The corresponding relative mechanical advantage 14 of the pumping system 10 is approximately maximum at these positions.
(21) FIG. 3A is a cross-sectional view of the pumping system 10 illustrating a non-limiting exemplary embodiment of operating the pumping system 10 within a high pressure region between HP.sub.1 and HP.sub.3. FIG. 3B illustrates non-limiting exemplary linear positions 16 of the piston 110 within the cylinder 130 when the pumping system 10 is operated between HP.sub.1 and HP.sub.3. In some embodiments, the drive shaft 150 oscillates or rotates back and forth, as shown by the arc arrow 18, between the positions HP.sub.1 and HP.sub.3. During one displacement or movement of the eccentric 160 and the connecting point 124 between HP.sub.1 and HP.sub.3, the piston 110 is linearly displaced or travels a distance L.sub.P1 within the cylinder 130. The dashed box 20 in FIG. 3B illustrates the linear position 16, viz., L.sub.P1, of the piston 110 and the corresponding relative mechanical advantage 14 when the pumping system 10 is operated in the high pressure region between HP.sub.1 and HP.sub.3. Minimum torque and minimum current draw occurs when the rate of displacement of the piston 110 is at a minimum with respect to the rate of change of the motor rotor angle which, in this instance, is approximately at the 12 o'clock position of the eccentric 160 and the connecting point 124. As illustrated, the linear position 16 of the piston 110 at HP.sub.2 approximately corresponds with the maximum relative mechanical advantage 14 in the high pressure region between HP.sub.1 and HP.sub.3. It should be noted that the drive shaft 150 does not complete one full rotation. A substantially similar high pressure region exists opposite the high pressure region between HP.sub.1 and HP.sub.3.
(22) FIG. 4A is a cross-sectional view of the pumping system 10 illustrating a non-limiting exemplary embodiment of operating the pumping system 10 within another high pressure region between HP.sub.4 and HP.sub.6 opposite the high pressure region between HP.sub.1 and HP.sub.3. FIG. 4B illustrates non-limiting exemplary linear positions 16 of the piston 110 within the cylinder 130 when the pumping system 10 is operated between HP.sub.4 and HP.sub.6. In some embodiments, the drive shaft 150 oscillates or rotates back and forth, as shown by the arc arrow 22, between the positions HP.sub.4 and HP.sub.6. During one displacement or movement of the eccentric 160 and the connecting point 124 between HP.sub.4 and HP.sub.6, the piston 110 is linearly displaced or travels a distance L.sub.P2 within the cylinder 130. The dashed box 24 in FIG. 4B illustrates the linear position 16, viz., L.sub.P2, of the piston 110 and the corresponding relative mechanical advantage 14 when the pumping system 10 is operated in the high pressure region between HP.sub.4 and HP.sub.6. Minimum torque and minimum current draw occurs when the rate of displacement of the piston 110 is at a minimum with respect to the rate of change of the motor rotor angle which, in this instance, is approximately at the 6 o'clock position of the eccentric 160 and the connecting point 124. As illustrated, the linear position 16 of the piston 110 at HP.sub.5 approximately corresponds with the maximum relative mechanical advantage 14 in the high pressure region between HP.sub.4 and HP.sub.6. It should be noted that the drive shaft 150 does not complete one full rotation.
(23) FIG. 5A is a cross-sectional view of the pumping system 10 illustrating a non-limiting exemplary embodiment of operating the pumping system 10 within a high flow region between HF.sub.1 and HF.sub.3. FIG. 5B illustrates non-limiting exemplary linear positions 16 of the piston 110 within the cylinder 130 when the pumping system 10 is operated between HF.sub.1 and HF.sub.3. In some embodiments, the drive shaft 150 oscillates or rotates back and forth, as shown by the arc arrow 26, between the positions HF.sub.1 and HF.sub.3. During one displacement or movement of the eccentric 160 and the connecting point 124 between HF.sub.1 and HF.sub.3, the piston 110 is linearly displaced or travels a distance L.sub.F1 within the cylinder 130. The dashed box 28 in FIG. 5B illustrates the linear position 16, viz., L.sub.F1, of the piston 110 and the corresponding relative mechanical advantage 14 when the pumping system 10 is operated in the high flow region between HF.sub.1 and HF.sub.3. Peak or maximum torque and maximum motor current draw occurs when the rate of displacement of the piston 110 is greatest with respect to the rate of change of the motor rotor angle which, in this instance, is at the 3 o'clock position of the eccentric 160 and the connecting point 124. As illustrated, the linear position 16 of the piston 110 at HF.sub.2 approximately corresponds with the highest flow displacement per change of angular position in the high flow region between HF.sub.1 and HF.sub.3. Also as illustrated, the relative mechanical advantage 14 during operation within the high flow region between HF.sub.1 and HF.sub.3 is a minimum which corresponds to a more consistent flow rate. It should be noted that the drive shaft 150 does not complete one full rotation. A substantially similar high flow region exists opposite the high flow region between HF.sub.1 and HF.sub.3.
(24) FIG. 6A is a cross-sectional view of the pumping system 10 illustrating a non-limiting exemplary embodiment of operating the pumping system 10 within a high flow region between HF.sub.4 and HF.sub.6 opposite the high flow region between HF.sub.1 and HF.sub.3. FIG. 6B illustrates non-limiting exemplary linear positions 16 of the piston 110 within the cylinder 130 when the pumping system 10 is operated between HF.sub.4 and HF.sub.6. In some embodiments, the drive shaft 150 oscillates or rotates back and forth, as shown by the arc arrow 30, between the positions HF.sub.4 and HF.sub.6. During one displacement or movement of the eccentric 160 and the connecting point 124 between HF.sub.4 and HF.sub.6, the piston 110 is linearly displaced or travels a distance L.sub.F2 within the cylinder 130. The dashed box 32 in FIG. 6B illustrates the linear position 16 of the piston 110 and the corresponding relative mechanical advantage 14 when the pumping system 10 is operated in the high flow region between HF.sub.4 and HF.sub.6. Peak or maximum torque and maximum motor current draw occurs when the rate of displacement of the piston 110 is greatest with respect to the rate of change of the motor rotor angle which, in this instance, is at the 9 o'clock position of the eccentric 160 and the connecting point 124. As illustrated, the linear position 16 of the piston 110 at HF.sub.5 approximately corresponds with the highest flow displacement per change of angular position in the high flow region between HF.sub.4 and HF.sub.6. Also as illustrated, the relative mechanical advantage 14 during operation within the high flow region between HF.sub.4 and HF.sub.6 is a minimum which corresponds to a more consistent flow rate. It should be noted that the drive shaft 150 does not complete one full rotation.
(25) FIG. 7 is a cross-sectional view of a non-limiting exemplary embodiment of a pump 34 having at least one ball valve 36 and a piston 210 configured for controlling the movement of material throughout the pump 34 and generating pressure. In a non-limiting exemplary embodiment, the ball valve 36 includes a ball 275 and a ball cage 270. In some embodiments, a connecting arm (e.g., connecting arm 120; not shown) and the piston 210 are connected at connection point 222. The opposite end of the connecting arm may be connected to the eccentric 160.
(26) FIG. 8 is a flow chart of a non-limiting exemplary embodiment of a method 900 for operating the pumping system 10 of the instant disclosure in the high pressure region between HP.sub.1 and HP.sub.3 illustrated in FIG. 3 or in the high pressure region between HP.sub.4 and HP.sub.6 illustrated in FIG. 4. In some embodiments, the method 900 operates without a position sensor. The method 900 begins at step 902 whereat the controller 170, via a processor, commands the drive shaft 150 to rotate in direction A. The torque and speed of the drive shaft 150 begin to increase, which is detected by the controller 170 via the processor. At step 904, the controller 170, via the processor, begins to limit the speed of the drive shaft 150 as the torque approaches an upper limit. At step 906, the speed of the drive shaft 150 decreases to the point of reaching a minimum speed limit, which is detected by the controller 170 via the processor. The controller 170, via the processor, commands the drive shaft 150 to stop. At step 908, the controller 170, via the processor, commands the drive shaft 150 to rotate in direction B opposite the direction A. The torque and speed of the drive shaft 150 begin to increase, which is detected by the controller 170 via the processor. At step 910, the controller 170, via the processor, begins to limit the speed of the drive shaft 150 as the torque approaches the upper limit. At step 912, the speed of the drive shaft 150 decreases to the point of reaching a minimum speed limit, which is detected by the controller 170 via the processor. The controller 170, via the processor, commands the drive shaft 150 to stop. The method 900 (or process) repeats starting at step 902.
(27) FIG. 9 is a flow chart of a non-limiting exemplary embodiment of a method 1000 for operating the pumping system 10 of the instant disclosure in the high flow region between HF.sub.1 and HF.sub.3 illustrated in FIG. 5 or in the high flow region between HF.sub.4 and HF.sub.6 illustrated in FIG. 6. In some embodiments, the method 1000 operates without a position sensor. The method 1000 begins at step 1002 whereat a controller 170, via a processor, commands the drive shaft 150 to rotate in direction A. The torque and speed of the drive shaft 150 begin to increase, and the speed of the drive shaft 150 reaches the maximum speed limit. At step 1004, the torque of the drive shaft 150 peaks at a value which is significantly below the maximum torque threshold, which is detected by the controller 170 via the processor. The torque value starts to decrease and eventually reaches a minimum torque threshold, which is detected by the controller 170 via the processor. The controller 170, via the processor, commands the drive shaft 150 to stop. At step 1006, the controller 170, via the processor, commands the drive shaft 150 to rotate in direction B opposite the direction A. The torque and speed of the drive shaft 150 begin to increase, which is detected by the controller 170 via the processor. The speed of the drive shaft 150 reaches the maximum speed limit, which is detected by the controller 170 via the processor. At step 1008, the torque of the drive shaft 150 peaks at a value which is significantly below the maximum torque threshold, which is detected by the controller 170 via the processor. The torque value starts to decrease and eventually reaches a minimum torque threshold, which is detected by the controller 170 via the processor. The controller 170, via the processor, commands the drive shaft 150 to stop. The method 1000 (or process) repeats starting at step 1002.
(28) FIG. 10 is a block diagram of a non-limiting exemplary embodiment of a control loop of the controller 170 for operating the pumping system 10 in one of the high pressure regions or in one of the high flow regions. The illustrated embodiment is directed to a pumping system 10 using an electric motor. In certain embodiments, several layers of feedback control loop may be implemented. In some embodiments, the pressure or flow control command is used as a set-point for the control logic. In certain embodiments, the control logic may be configured for using motor speed, motor torque, motor position, and pump position as inputs for decision making. In some embodiments, the control logic may control or output commands for controlling the motor position, motor speed, and motor torque. In a non-limiting exemplary embodiment, the control logic determines whether the eccentric 160 should run continuously as illustrated in FIG. 2 or only operate within certain ranges of rotation as illustrated in one or more of FIGS. 3 through 6. In some embodiments, the controller 170 is configured to measure motor current and measure or estimate the motor position and speed using components and/or methods well known in the art including, but not limited to, sensor-less control algorithms, encoders, feedback loops, hall sensors, among others. In certain embodiments, the controller 170 is configured to ascertain the position of the drive shaft 150 using components and/or methods well known in the art including, but not limited to, sensor-less control algorithms, e.g., via motor current and speed measurements and estimates, and clocking signals from an external position sensor.
(29) In view thereof, modified and/or alternate configurations of the embodiments described herein may become apparent or obvious to one of ordinary skill. All such variations are considered as being within the metes and bounds of the instant disclosure. For instance, while reference may have been made to particular feature(s) and/or function(s), the disclosure is considered to also encompass any and all equivalents providing functionalities similar to those disclosed herein with reference to the accompanying drawings. Accordingly, the spirit, scope and intent of the instant disclosure is to embrace all such variations. Consequently, the metes and bounds of the instant disclosure are defined by the appended claims and any and all equivalents thereof.
