Method of determining pump flow in rotary positive displacement pumps

Abstract

Techniques are provided for tuning a rotary positive displacement pump. The techniques include apparatus featuring a signal processor configured to the present invention may take the form of apparatus comprising a signal processor that may be configured to receive signaling containing information about actual pump performance data related to the operation of a rotary positive displacement pump; and determine corrected published pump performance data to operate the rotary positive displacement pump by compensating published pump performance data based at least partly on the actual pump performance data. The corrected published pump performance data may include a corrected published rated power, flow and slip factor, and the actual pump performance data contains information about actual power, specific gravity and viscosity related to the operation of the rotary positive displacement pump and received from a pump controller or controlling device, including a variable frequency drive.

Claims

1. Apparatus comprising: a signal processor configured to receive signaling containing information about actual pump performance data related to the operation of a rotary positive displacement pump; and determine corresponding signaling containing information about corrected published pump performance data to operate the rotary positive displacement pump by compensating published pump performance data based at least partly on the actual pump performance data; wherein the corrected published pump performance data include a corrected published rated power, a corrected published rated flow and a rated slip factor compensated for actual conditions; wherein the signal processor is configured to determine the corrected published rated power based upon the following equation:
RTD HP.sub.CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT)/(VISC.sub.ACT/VISC.sub.RTD)^N, where: RTD HP.sub.CORR is the corrected published rated power in the form of rated hp corrected for specific gravity and viscosity, HP.sub.ACT is the actual power at rated conditions, SG.sub.RTD is the rated specific gravity of the pumped liquid, SG.sub.ACT is the actual specific gravity of the pumped liquid, VISC.sub.RTD is the rated viscosity of the pumped liquid, VISC.sub.ACT is the actual viscosity of the pumped liquid, and N is an exponent which varies by the type of pump.

2. Apparatus according to claim 1, wherein N equals about 0.10 for rotary PD pumps such as gear, vane and lobe, and wherein N equals about 0.275 for progressive cavity pumps.

3. Apparatus according to claim 1, wherein the signal processor is configured to determine the corrected published rated flow based upon the following equation:
Q.sub.RATEDCORR=(RTD HP.sub.CORR/RTD HP)Q RTD, where: Q.sub.RATEDCORR is the corrected rated flow, RTD HP is the corrected published rated power in the form of the rated hp for the application, and Q RTD is the rated flow for the application.

4. Apparatus according to claim 3, wherein the signal processor is configured to determine the rated slip factor compensated for actual conditions based at least partly on the following equation:
KS=(VISC.sub.RTDQ.sub.NO SLIP(Q.sub.NO SLIPQ.sub.RATED CORR)/(75.415K.sub.G(N.sub.RATED)T.sub.RTD CORR), where: KS is the rated slip factor compensated for actual conditions, VISC.sub.RTD is the published pump rated viscosity, Q.sub.NO SLIP is the flow in gpm at rated speed and rated viscosity at 0 psid differential pressure, Q.sub.RATEDCORR is the corrected rated flow, K.sub.G=0.004329, a design constant, N.sub.RATED=Rated Pump Speed for the application, and T.sub.RTD CORR=Corrected Rated Torque in Ft-Lbs (US), which is determined as follows: T.sub.RTD CORR=(5252RTD HP.sub.CORR)/N.sub.RTD.

5. Apparatus according to claim 4, wherein the signal processor is configured to determine an actual flow value for the rotary positive displacement pump based at least partly on the following equation:
Q.sub.ACT CORR=(Q.sub.NO SLIP((N.sub.MOTOR/RATIO)/N.sub.RATED))(((75.415K.sub.GKS.sub.CORR)(N.sub.MOTOR/RATIO)TACT.sub.CORR)/(VISCOSITY.sub.ACTQ.sub.NO SLIP), where: Q.sub.NO SLIP is the flow in gpm at rated speed and rated viscosity at 0 psid differential pressure, N.sub.MOTOR=the current motor speed, RATIO=the ratio of speed reduction if a gear reducer is used. If no gear reducer is used than the value of the RATIO=1.0. N.sub.RATED=the Rated Pump Speed for the application, K.sub.G=0.004329, a design constant, KS.sub.CORR is the corrected rated slip factor based on the slip rules for the operating condition for a particular rotary positive displacement pump type, T.sub.ACT CORR=Torque in Ft-Lbs (US), where T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, and HP.sub.ACT CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT), HP.sub.ACT=Actual motor power, N.sub.ACT=Actual pump speed, and VISC.sub.ACT is the actual viscosity of the pumped liquid.

6. Apparatus according to claim 5, wherein the signal processor is configured to determine slip rules for rotary positive displacement pumps and magnetic drive rotary positive displacement pumps based at least partly on Table I below: TABLE-US-00003 Changing Variable Corrected Slip Factor KS.sub.CORR Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and Viscosity KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed, Torque and KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) * Viscosity (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5, and wherein the signal processor is configured to determine slip rules for progressive cavity pumps and magnetic drive progressive cavity pumps based at least partly on Table II below: TABLE-US-00004 TABLE II Changing Variable Corrected Slip Factor KS.sub.CORR Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and Viscosity KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed, Torque and KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5. Viscosity

7. Apparatus according to claim 6, wherein the signal processor is configured to determine the result of the flow calculation as follows: Q.sub.ACT CORR=Q.sub.ACT, and the Q.sub.ACT CORR is displayed as the actual flow (Q.sub.ACT) in Gpm.

8. Apparatus according to claim 7, wherein the signal processor is configured to determine the parameters for actual and rated pump speed as follows: N.sub.ACT=Actual pump speed, and N.sub.RTD=Rated pump speed of the application.

9. Apparatus according to claim 8, wherein for magnetic drive rotary positive displacement pumps the signal processor is configured to determine the following parameters: T.sub.ACT CORR=Torque in Ft-Lbs (US), which is calculated as follows: T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, where:
HP.sub.ACT CORR=(HP.sub.ACT(P.sub.MAG CORR(N.sub.ACT/N.sub.RTD).sup.2)SG.sub.RTD/SG.sub.ACT), HP.sub.ACT=Actual motor power, and P.sub.MAG CORR is the eddy current loss in Hp at rated speed for a containment shell material used.

10. A method comprising: receiving with a signal processor signaling containing information about actual pump performance data related to the operation of a rotary positive displacement pump; and determining with the signal processor corresponding signaling containing information about corrected published pump performance data to operate the rotary positive displacement pump by compensating published pump performance data based at least partly on the actual pump performance data; wherein the corrected published pump performance data include a corrected published rated power, a corrected published rated flow and a rated slip factor compensated for actual conditions; and wherein the method comprises determining with the signal processor the corrected published rated power based upon the following equation:
RTD HP.sub.CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT)/(VISC.sub.ACT/VISC.sub.RTD)^N, where: RTD HP.sub.CORR is the corrected published rated power in the form of rated hp corrected for specific gravity and viscosity, HP.sub.ACT is the actual power at rated conditions, SG.sub.RTD is the rated specific gravity of the pumped liquid, SG.sub.ACT is the actual specific gravity of the pumped liquid, VISC.sub.RTD is the rated viscosity of the pumped liquid, VISC.sub.ACT is the actual viscosity of the pumped liquid, and N is an exponent which varies by the type of pump.

11. A method according to claim 10, wherein N equals about 0.10 for rotary PD pumps such as gear, vane and lobe, and wherein N equals about 0.275 for progressive cavity pumps.

12. A method according to claim 10, wherein the method comprises determining with the signal processor the corrected published rated flow based upon the following equation:
Q.sub.RATEDCORR=(RTD HP.sub.CORR/RTD HP)Q RTD, where: Q.sub.RATEDCORR is the corrected rated flow, RTD HP is the corrected published rated power in the form of the rated hp for the application, and Q RTD is the rated flow for the application.

13. A method according to claim 12, wherein the method comprises determining with the signal processor the rated slip factor compensated for actual conditions based at least partly on the following equation:
KS=(VISC.sub.RTDQ.sub.NO SLIP(Q.sub.NO SLIPQ.sub.RATED CORR)/(75.415K.sub.G(N.sub.RATED)T.sub.RTD CORR), where: KS is the rated slip factor compensated for actual conditions, VISC.sub.RTD is the published pump rated viscosity, Q.sub.NO SLIP is the flow in gpm at rated speed and rated viscosity at 0 psid differential pressure, Q.sub.RATEDCORR is the corrected rated flow, K.sub.G=0.004329, a design constant, N.sub.RATED=Rated Pump Speed for the application, and T.sub.RTD CORR=Corrected Rated Torque in Ft-Lbs (US), which is determined as follows: T.sub.RTD CORR=(5252RTD HP.sub.CORR)/N.sub.RTD.

14. A method according to claim 13, wherein the method comprises determining with the signal processor an actual corrected flow value for the rotary positive displacement pump based upon the following equation:
Q.sub.ACT CORR=(Q.sub.NO SLIP((N.sub.MOTOR/RATIO)/N.sub.RATED))(((75.415K.sub.GKS.sub.CORR)(N.sub.MOTOR/RATIO)TACT.sub.CORR)/(VISCOSITY.sub.ACTQ.sub.NO SLIP), where: Q.sub.NO SLIP is the flow in gpm at rated speed and rated viscosity at 0 psid differential pressure, N.sub.MOTOR=the current motor speed, RATIO=the ratio of speed reduction if a gear reducer is used. If no gear reducer is used than the value of the RATIO=1.0. N.sub.RATED=the Rated Pump Speed for the application, K.sub.G=0.004329, a design constant, KS.sub.CORR is the corrected rated slip factor determined from slip rules for the operating condition for a particular rotary positive displacement pump type, T.sub.ACT CORR=Torque in Ft-Lbs (US), where T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, and HP.sub.ACT CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT), HP.sub.ACT=Actual motor power, N.sub.ACT=Actual pump speed, and VISC.sub.ACT is the actual viscosity of the pumped liquid.

15. A method according to claim 14, wherein the method comprises determining slip rules for rotary positive displacement pumps and magnetic drive rotary positive displacement pumps based at least partly on Table I below: TABLE-US-00005 Changing Variable Corrected Slip Factor KS.sub.CORR Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and Viscosity KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed, Torque and KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) * Viscosity (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5, and wherein the method comprises determining slip rules for progressive cavity pumps and magnetic drive progressive cavity pumps based at least partly on Table II below: TABLE-US-00006 TABLE II Changing Variable Corrected Slip Factor KS.sub.CORR Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and Viscosity KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed, Torque and KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5. Viscosity

16. A method according to claim 15, wherein the method comprises determining the result of the flow calculation as follows: Q.sub.ACT CORR=Q.sub.ACT, and the Q.sub.ACT CORR is displayed as the actual flow (Q.sub.ACT) in Gpm.

17. A method according to claim 16, wherein the method comprises determining the parameters for actual and rated pump speed as follows: N.sub.ACT=Actual pump speed, and N.sub.RTD=Rated pump speed of the application.

18. A method according to claim 17, wherein for magnetic drive rotary positive displacement pumps the method comprises determining the following parameters: T.sub.ACT CORR=Torque in Ft-Lbs (US), which is calculated as follows: T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, where:
HP.sub.ACT CORR=(HP.sub.ACT(P.sub.MAG CORR(N.sub.ACT/N.sub.RTD).sup.2)SG.sub.RTD/SG.sub.ACT), HP.sub.ACT=Actual motor power, and P.sub.MAG CORR is the eddy current loss in Hp at rated speed for a containment shell material used.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The drawing includes the following Figures:

(2) FIG. 1 is a graph of power (HP) versus discharge pressure (PSIG) related to a power comparison of published versus test data at 200 Cp, 1750 Rpm for a rotary positive displacement pump.

(3) FIG. 2 is a graph of capacity (GPM) versus discharge pressure (PSIG) for a capacity comparison of published versus test data at 200 Cp, 1750 Rpm for a rotary positive displacement pump.

(4) FIG. 3 is a block diagram of apparatus according to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) By way of example, as shown in FIG. 3, according to some embodiments, the present invention may take the form of apparatus 10 that includes a signal processor 12 that may be configured to control and protect the operation of a rotary positive displacement pump 14, e.g., which may include, or take the form of, an internal or external gear pump, a lobe pump, a vane pump or a progressive cavity pump.

(6) The signal processor 12 may be configured to receive signaling containing information about actual pump performance data related to the operation of the rotary positive displacement pump 14 and determine corrected published pump performance data to operate the rotary positive displacement pump by compensating published pump performance data based at least partly on the actual pump performance data.

(7) The signal processor 12 may also be configured to determine an actual flow value for the rotary positive displacement pump based at least partly on the corrected published pump performance data, and to provide a control signal containing information about an actual flow value to control the operation of the rotary positive displacement pump.

(8) The rotary positive displacement pump 14 may include a module 16 configured to provide the signaling containing information about actual pump performance data related to the operation of the rotary positive displacement pump 14, and may also be configured to receive the control signal containing information about the actual flow value to control the operation of the rotary positive displacement pump 14.

(9) By way of example, the signal processor 12 may be implemented consistent with that set forth below:

The Implementation

(10) The logic according to the present invention works by compensating published values of rated power, rated flow and rated slip factor for actual rated conditions, as follows: The published rated power may be compensated for actual power, actual specific gravity and actual viscosity at rated conditions. This becomes the corrected rated power. The published rated flow may be compensated for actual rated conditions based on the corrected rated power. This becomes the corrected rated flow. The rated slip factor, calculated from published data, may be compensated for actual rated conditions based on the corrected rated power and corrected rated flow.

(11) Once these values are calculated and a tune function is activated the published values for Rated HP, Rated Flow and Rated Slip Factor are replaced by the corresponding compensated or corrected values. These compensated or corrected values are saved and do not change unless another tune function is initiated. Note the tune function is typically activated while the pump is operating at rated speed and rated conditions.

(12) By way of example, the technique of compensation and flow calculation may consist of the following steps:

(13) a) Rated HP Compensation (RTD HP.sub.CORR)

(14) For instance, the signal processor 12 may be configured to determine the corrected published rated power based at least partly on the following equation:
RTD HP.sub.CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT)/(VISC.sub.ACT/VISC.sub.RTD)^N,
where:

(15) RTD HP.sub.CORR is the rated hp corrected for specific gravity and viscosity,

(16) HP.sub.ACT is the actual power at rated conditions,

(17) SG.sub.RTD is the rated specific gravity of the pumped liquid,

(18) SG.sub.ACT is the actual specific gravity of the pumped liquid,

(19) VISC.sub.RTD is the rated viscosity of the pumped liquid,

(20) VISC.sub.ACT is the actual viscosity of the pumped liquid, and

(21) N is an exponent which varies by the type of pump.

(22) By way of example, for rotary PD pumps such as gear, vane and lobe, the exponent N equals about 0.10, and for progressive cavity pumps, the exponent N equals about 0.275.

(23) The scope of the invention is not intended to be limited to the specific aforementioned equation and parameters set forth above to determine the corrected published rated power. For example, embodiments are envisioned in which variations of the aforementioned equation and/or parameters may be used to determine the corrected published rated power consistent with that now known or later developed in the future.

(24) b) Rated Flow Compensation (Q.sub.RATEDCORR)

(25) For instance, the signal processor 12 may be configured to determine the corrected published rated flow based at least partly on the following equation:
Q.sub.RATEDCORR=(RTD HP.sub.CORR/RTD HP)Q RTD,

(26) Note that Q.sub.RATEDCORR is calculated at rated speed.

(27) Where:

(28) Q.sub.RATEDCORR is the corrected rated flow

(29) RTD HP.sub.CORR is the rated hp corrected for specific gravity and viscosity,

(30) RTD HP is the rated hp for the application

(31) Q RTD is the rated flow for the application

(32) The scope of the invention is not intended to be limited to the specific aforementioned equation and parameters set forth above to determine the corrected published rated flow. For example, embodiments are envisioned in which variations of the aforementioned equation and/or parameters may be used to determine the corrected published rated flow consistent with that now known or later developed in the future.

(33) c) Rated Slip Factor Compensation (KS):

(34) For instance, the signal processor 12 may be configured to determine the rated slip factor KS compensated for actual conditions based at least partly on the following equation:
KS=(VISC.sub.RTDQ.sub.NO SLIP(Q.sub.NO SLIPQ.sub.RATED CORR)/(75.415K.sub.G(N.sub.RTD)T.sub.RTD CORR),
where:

(35) KS is the rated slip factor compensated for actual conditions,

(36) Q.sub.NO SLIP is the flow in Gpm at rated speed and rated viscosity at 0 psid differential pressure,

(37) Q.sub.RATEDCORR is the corrected rated flow,

(38) K.sub.G=0.004329, a design constant,

(39) N.sub.RTD=Rated Pump Speed for the application, and

(40) T.sub.RTD CORR=Corrected Rated Torque in Ft-Lbs (US), which is calculated as follows: T.sub.RTD CORR=(5252RTD HP.sub.CORR)/N.sub.RTD, where

(41) RTD HP.sub.CORR is the rated hp corrected for specific gravity and viscosity.

(42) The scope of the invention is not intended to be limited to the specific aforementioned equation and parameters set forth above to determine the rated slip factor. For example, embodiments are envisioned in which variations of the aforementioned equation and/or parameters may be used to determine the rated slip factor consistent with that now known or later developed in the future.

(43) d) Tune Function Activation

(44) To calculate and save values calculated in steps a-c, the signal processor 12 is configured to activate the tune function process while the pump is stable and operating at rated conditions. The tune function process is seamless to the user. Tuning samples actual conditions without changing operating conditions or pump speed. Once tuning is completed, the values for RTD HP.sub.CORR, Q.sub.RATED CORR and KS are saved. These values do not change unless another tune function process is re-initiated.

(45) Periodically as wear occurs, pump flow accuracy can be restored by re-activating this parameter when operating at rated conditions.

(46) e) The Actual Flow Calculation

(47) For instance, the rated slip factor, KS, may be corrected for changing variables due to operating conditions by the slip rules for rotary and progressive cavity pumps as shown in Tables I and II. The corrected slip factor becomes KS.sub.CORR.

(48) The signal processor 12 may be configured to determine an actual flow value for the rotary positive displacement pump based at least partly on the following equation:
Q.sub.ACT CORR=(Q.sub.NO SLIP((N.sub.MOTOR/RATIO)/N.sub.RTD))(((75.415K.sub.GKS.sub.CORR)(N.sub.MOTOR/RATIO)T.sub.ACT CORR)/(VISC.sub.ACTQ.sub.NO SLIP),
where:

(49) Q.sub.NO SLIP is the flow in Gpm at rated speed and rated viscosity at 0 psid differential pressure,

(50) N.sub.MOTOR=current motor speed,

(51) RATIO=the ratio of speed reduction if a gear reducer is used (If no gear reducer is used than the value of the RATIO=1.0.),

(52) N.sub.RTD=Rated Pump Speed for the application,

(53) K.sub.G=0.004329, a design constant,

(54) VISC.sub.ACT is the actual viscosity of the pumped liquid,

(55) T.sub.ACT CORR=Torque in Ft-Lbs (US), which is calculated as follows: T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, where HP.sub.ACT CORR=HP.sub.ACT(SG.sub.RTD/SG.sub.ACT), and

(56) KS.sub.CORR=corrected slip factor based on slip rules for the operating condition as shown in Tables I and II.

(57) For constant temperature applications, a specific gravity value is not required and HP.sub.ACT CORR=HP.sub.ACT, where

(58) HP.sub.ACT=Actual motor power, and

(59) N.sub.ACT=Actual pump speed.

(60) Adjustments to the rated slip factor, KS, may be made by the slip rules shown below, which results in a corrected slip factor, KS.sub.CORR.

(61) TABLE-US-00001 TABLE I Slip Rules for Rotary PD Pumps and Magnetic Drive Rotary PD Pumps: Changing Variable Corrected Slip Factor KS.sub.CORR used in step e Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and SLIP FACTOR is Constant; KS.sub.CORR = KS Torque Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* Viscosity (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Viscosity Speed, Torque KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) * and Viscosity (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5

(62) TABLE-US-00002 TABLE II Slip Rules for Progressive Cavity Pumps and Magnetic Drive Progressive Cavit Pumps: Changing Variable Corrected Slip Factor KS.sub.CORR used in step e Torque SLIP FACTOR is Constant; KS.sub.CORR = KS Speed KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT) Speed and SLIP FACTOR is Constant; KS.sub.CORR = KS Torque Viscosity KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Speed and KS.sub.CORR = KS * (N.sub.RATED/N.sub.ACT)* Viscosity (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Torque and KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 Viscosity Speed, Torque KS.sub.CORR = KS * (Visc.sub.ACT/Visc.sub.RATED){circumflex over ()}0.5 and Viscosity

(63) The result of the flow calculation in step (e) is as follows:

(64) Q.sub.ACT CORR=Q.sub.ACT, and

(65) the Q.sub.ACT CORR is displayed as the actual flow (Q.sub.ACT) in Gpm.

(66) In the tables, the parameters for actual and rated pump speed are as follows:

(67) N.sub.ACT=Actual pump speed, and

(68) N.sub.RTD=Rated pump speed of the application.

(69) For magnetic drive rotary and magnetic drive progressive cavity PD pumps: T.sub.ACT CORR=Torque in Ft-Lbs (US), which is calculated as follows: T.sub.ACT CORR=(5252HP.sub.ACT CORR)/N.sub.ACT, where:
HP.sub.ACT CORR=(HP.sub.ACT(P.sub.MAG CORR(N.sub.ACT/N.sub.RTD).sup.2)SG.sub.RTD/SG.sub.ACT),

(70) HP.sub.ACT=Actual motor power, and

(71) P.sub.MAG CORR is the eddy current loss in Hp at rated speed for the containment shell material used. Note for non-metallic containment shells the eddy current loss is 0 hp.

(72) The scope of the invention is not intended to be limited to the specific aforementioned equation and parameters set forth above to determine the actual flow value. For example, embodiments are envisioned in which variations of the aforementioned equation and/or parameters may be used to determine the actual flow value consistent with that now known or later developed in the future.

The Signal Processor 12

(73) The signal processor 12 performs the basic signal processing functionality of the apparatus for implementing the present invention. The signal processor 12 may be a stand alone signal processing module, form part of a controller, controller module, etc., or form part of some other module of the apparatus 10. Many different types and kind of signal processors, controllers and controller modules for controlling pumps are known in the art. Some examples are variable frequency drives and programmable logic controllers. By way of example, based on an understanding of such known signal processing modules, controllers and control modules, a person skilled in the art would be able to configure the signal processor 12 to perform the functionality consistent with that described herein, including to receive the signaling containing information about actual pump performance data related to the operation of the rotary positive displacement pump 14; and to determine corrected published pump performance data to operate the rotary positive displacement pump 14 by compensating published pump performance data based at least partly on the actual pump performance data. By way of further example, based on an understanding of such known signal processing modules, controllers and control modules, a person skilled in the art would be able to configure the signal processor 12 to perform functionality consistent with that described herein, including to determine an actual flow value for the rotary positive displacement pump based at least partly on the corrected published pump performance data, and to provide a control signal containing information about an actual flow value to control the operation of the rotary positive displacement pump.

(74) By way of still further example, the functionality of the signal processor 12 may be implemented using hardware, software, firmware, or a combination thereof, although the scope of the invention is not intended to be limited to any particular embodiment thereof. In a typical software implementation, such a module would be one or more microprocessor-based architectures having a microprocessor, a random access memory (RAM), a read only memory (ROM), input/output devices and control, data and address buses connecting the same. A person skilled in the art would be able to program such a microprocessor-based implementation to perform the functionality described herein without undue experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology known or later developed in the future.

(75) The signal processor, controller or controller module may include other modules to perform other functionality that is known in the art, that does not form part of the underlying invention, and that is not described in detail herein.

The Rotary Positive Displacement Pump 14

(76) The rotary positive displacement pump like element 14, and rotary positive displacement pumps in general, are known in the art, e.g., which may include an internal or external gear pump, a lobe pump, a vane pump or a progressive cavity pump, and not described in detail herein. Moreover, the scope of the invention is not intended to be limited to any particular type or kind of positive displacement machine thereof that is either now known or later developed in the future. By way of example, such rotary positive displacement pumps are understood to include a motor or motor portion for driving a pump or pump portion, and may include a module like element 16 for implementing some functionality related to controlling the basic operation of the motor for driving the pump 14. By way of example, and consistent with that set forth herein, the motor is understood to receive control signals from the signal processor in order to drive and control the rotary positive displacement pump to pump fluid. The motor is also understood to provide the signaling containing information about power, torque and speed related to the operation of the pump.

Other Possible Applications

(77) Other possible applications include at least the following:

(78) Rotary positive displacement pump flow calculationsflow estimations for rotary positive displacement pumps rely upon accurate power curves to estimate pump flow. Published performance for certain types of positive displacement pumps such as progressive cavity pumps have been found to differ from actual performance based on anticipated wear in the stator liner. The tune function described above will correct the calculated flow value based on published performance to reflect actual pump performance for rotary positive displacement pumps.

(79) The tune function can also restore flow accuracy by compensating for pump wear.

THE SCOPE OF THE INVENTION

(80) It should be understood that, unless stated otherwise herein, any of the features, characteristics, alternatives or modifications described regarding a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. Also, the drawings herein are not drawn to scale.

(81) Although the invention has been described and illustrated with respect to exemplary embodiments thereof, the foregoing and various other additions and omissions may be made therein and thereto without departing from the spirit and scope of the present invention.