Optimized technique for staging and de-staging pumps in a multiple pump system

Abstract

Apparatus is provided featuring a signal processor or processing module configured at least to: receive signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system; and determine whether to stage or de-stage a pump in the multiple pump system, based at least partly on the signaling received. The signal processor or processing module is configured to provide corresponding signaling containing information about whether to stage or de-stage the pump in the multiple pump system, and to implement control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of specific energy that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system.

Claims

1. Apparatus comprising: a signal processor or processing module configured at least to: receive signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system, and also about corresponding system energy consumption related to corresponding multiple pump combinations for staging or destaging a pump in the multiple pump system; and determine corresponding signaling containing information about whether to stage or de-stage the pump in the multiple pump system, based in part upon a comparison of the system energy consumption and the corresponding system energy consumption and the signaling received; wherein the signal processor or processing module is configured to implement control logic or a control logic algorithm and determine if the multiple pump system is operating normally, based upon at least the following three conditions:
PV.sub.ACT=Set Point,
Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<BEP Limit Ratio, and
P.sub.ACT<P.sub.RTDSF, where PV.sub.ACT is an Actual Process Variable received from one or more sensors located on the pump; Set Point is a setting related to flow and pressure for the multiple pump system; Q=Q.sub.CALC or Q.sub.AVG, in which Q.sub.CALC is a calculated Flow for pump n, Q.sub.AVG is an average pump flow, and Q.sub.AVG being Q.sub.FM/n for Q.sub.FM is the flow meter reading and n is the number of pumps running; Q.sub.BEP is a Best Efficiency Flow at a rated pump speed; N.sub.ACT is an Actual Pump Speed; N.sub.RTD is a Rated Pump Speed; P.sub.ACT is an Actual Pump Power; P.sub.RTD is a Motor Rating; and SF represents a motor service factor.

2. Apparatus according to claim 1, wherein the signal processor or processing module is configured to provide the corresponding signaling as control signaling to stage or de-stage the pump in the multiple pump system.

3. Apparatus according to claim 1, wherein the signal processor or processing module is configured to implement control logic or a control logic algorithm based upon the system energy consumption taking the form of specific energy that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system.

4. Apparatus according to claim 3, wherein the signal processor or processing module is configured to determine the specific energy of current pumps running and an effect on a total system specific energy of adding another pump to meet process demands related to the multiple pump system.

5. Apparatus according to claim 4, wherein the signal processor or processing module is configured in a first case to make the comparison between two calculated values of system specific energy; and to choose a pump combination either having a lesser value for staging, or having a greater value for de-staging.

6. Apparatus according to claim 5, wherein the signal processor or processing module is configured in a second case to evaluate and not consider for selection any pump in a pump combination having a power value which exceeds a nameplate motor rating multiplied by a pre-selected service factor.

7. Apparatus according to claim 6, wherein the signal processor or processing module is configured to stage automatically an additional pump if either cases occurs prior to calculating the system specific energy.

8. Apparatus according to claim 1, wherein the signal processor or processing module is configured as, or forms part of, at least one variable speed drive with embedded control logic to optimize the staging or de-staging of pumps in the multiple pump system, including with the use of additional external inputs.

9. Apparatus according to claim 1, wherein the signal processor or processing module is configured with control logic or a control logic algorithm that utilizes calculated flow data that is mathematically determined from various pump and motor parameters, including speed, torque or power or from calibrated flow curves stored in an evaluation device.

10. Apparatus according to claim 1, wherein the signal processor or processing module is configured with control logic or a control logic algorithm that uses any drive parameter that has a direct relationship to pump flow.

11. Apparatus according to claim 1, wherein the signal processor or processing module is configured to implement control logic or a control logic algorithm based upon the system energy consumption taking the form of relative measures of pumping efficiency, including flow economy which is substantially equal to flow/wire-water power.

12. Apparatus according to claim 1, the signal processor or processing module is configured to determine when the multiple pump system is operating in a normal condition, and calculate and save a specific energy for a lead pump, based upon the equation:
SE=kW.sub.W-W/(Q60)=kWHr/G, and
SE.sub.TOTAL 1=SE.sub.PMP1, where SE is a calculated Specific Energy for a Pump, kW.sub.W-W is an Actual Wire to Water Power, SE.sub.TOTAL 1 is a Calculated System Specific Energy for a one pump system, and SE.sub.PMP1 is a Calculated Specific Energy for Pump 1.

13. Apparatus according to claim 12, wherein the signal processor or processing module is configured to determine to stage a first lag pump, and after a condition normal is reached, calculate a system specific energy SE for the lead pump and the first lag pump, based upon the equation as follows:
SE.sub.TOTAL 2=SE.sub.PMP1+SE.sub.PMP2, where SE.sub.TOTAL 2 is a Calculated System Specific Energy for a two pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump and SE.sub.PMP2 is a Calculated Specific Energy for Pump 2 corresponding to the first lag pump.

14. Apparatus according to claim 13, wherein the signal processor or processing module is configured to determine an optimum number of pumps which should run for the operating condition, and make a comparison between SE.sub.TOTAL2, for the lead pump and the first lag pump running, and SE.sub.TOTAL1 for the lead pump only running, based upon the equation:
SE.sub.TOTAL2<SE.sub.TOTAL1, where if True, then the first lag pump remains staged, and if False, then the first lag pump is de-staged.

15. Apparatus according to claim 1, wherein the signal processor or processing module is configured to determine when the multiple pump system is operating in a second condition, if either: the BEP Limit Ratio and/or motor power requirement are false, including even if PV.sub.ACT=Set Point, or PV.sub.ACT<set point and the current operating speed, and N.sub.ACT is >=0.98N.sub.MAX, then the first lag pump is staged.

16. Apparatus according to claim 15, wherein the signal processor or processing module is configured to determine when the multiple pump system is operating in the second condition, and also determine not to calculate an SE value when the lead pump only is running.

17. Apparatus according to claim 15, wherein the signal processor or processing module is configured to determine when the multiple pump system is operating in the second condition and the first lag pump is staged, calculate and save the SE.sub.TOTAL2 once condition normal is reached, and determine to stage a second lag pump, and calculate SE.sub.TOTAL3 once condition normal is reached, based upon the following:
SE.sub.TOTAL3=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3, where SE.sub.TOTAL 3 is a Calculated System Specific Energy for a three pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump, SE.sub.PMP2 is a Calculated Specific Energy for Pump 2 corresponding to the first lag pump, and SE.sub.PMP3 is a Calculated Specific Energy for Pump 3 corresponding to the second lag pump.

18. Apparatus according to claim 17, wherein the signal processor or processing module is configured to determine an optimum number of pumps which should run for the operating condition, and make a comparison between SE.sub.TOTAL3, for the lead pump, the first lag pump and the second lag pump running, and SE.sub.TOTAL2 for the lead pump and the first lag pump running, based upon the equation:
SE.sub.TOTAL3<SE.sub.TOTAL2, where if True, then the first lag pump and the second lag pump remain staged, and if False, then the second lag pump is de-staged.

19. Apparatus according to claim 1, wherein the signal processor or processing module is configured to determine when the multiple pump system is operating in a normal condition, and calculate and save a specific energy for n pumps, including a lead pump and one or more lag pumps, based upon the equation:
SE=kW.sub.W-W/(Q60)=kWHr/G, and
SE.sub.TOTAL n=SE.sub.PMP1+SE.sub.PMP2,+SE.sub.PMP3, . . . ,SE.sub.PMPn, where SE is a calculated Specific Energy for a Pump, kW.sub.W-W is an Actual Wire to Water Power, SE.sub.TOTAL n is a Calculated System Specific Energy for an n pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump, and SE.sub.PMP2 to SE.sub.PMPn are one or more Calculated Specific Energy for one or more Pumps 2 to n corresponding to the one or more lag pumps.

20. Apparatus according to claim 19, wherein the signal processor or processing module in a first operating condition is configured to determine to de-stage a first lag pump) if the set point change results in a speed (N.sub.ACT/N.sub.RTD %) or torque (T.sub.ACT %) value being above a Low Limit % and after a condition normal is reached, calculate a system specific energy SE for n1 pumps, including the lead pump and any remaining staged lag pumps, based upon the equation as follows:
SE.sub.TOTAL n-1=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3, . . . ,+SE.sub.PMPn-1, where SE.sub.TOTAL n-1 is a Calculated System Specific Energy for an n1 pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump, and SE.sub.PMP2 to SE.sub.PMPn-1 are Calculated Specific Energy for Pumps 2 to n1 corresponding to any remaining staged lag pumps.

21. Apparatus according to claim 20, wherein the signal processor or processing module is configured to determine an optimum number of pumps which should run for the operating condition, and make a comparison between SE.sub.TOTALn, for the pumps 1 to n running, and SE.sub.TOTALn-1 for the n1 pumps only running, based upon the equation:
SE.sub.TOTALn<SE.sub.TOTALn-1, where if True, then the first lag pump is re-staged, and if False, then the pumps 1 to n1 remain staged and the first lag pump remains de-staged.

22. Apparatus according to claim 19, wherein the signal processor or processing module is configured to determine in a second operating condition that the set point change results in a speed (N.sub.ACT/N.sub.RTD %) or torque (T.sub.ACT %) value being below a Low Limit % when a condition normal exists, and automatically de-stage a first lag pump, and once the condition normal is reached, calculate the specific energy for SE.sub.TOTALn-1, including the lead pump and any remaining staged lag pumps, based upon the following:
SE.sub.TOTALn-1=SE.sub.PMP1+SE.sub.PMP2+, . . . ,+SE.sub.PMPn-1, where SE.sub.TOTAL n-1 is a Calculated System Specific Energy for n1 pumps running in a multiple pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump, and SE.sub.PMP2 to SE.sub.PMPn-1 are Calculated Specific Energy for Pumps 2 to n1 corresponding to any remaining staged lag pumps.

23. Apparatus according to claim 22, wherein the signal processor or processing module in a second operating condition is configured to determine to de-stage a second lag pump and after a condition normal is reached, calculate a system specific energy SE for n2 pumps, including the lead pump and any remaining staged lag pumps, based upon the equation as follows:
SE.sub.TOTAL n-2=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3, . . . ,+SE.sub.PMPn-2, where SE.sub.TOTAL n-2 is a Calculated System Specific Energy for an n2 pump system, SE.sub.PMP1 is a Calculated Specific Energy for Pump 1 corresponding to the lead pump, and SE.sub.PMP2 to SE.sub.PMPn-2 are Calculated Specific Energy for Pumps 2 to n2 corresponding to any remaining staged lag pumps.

24. Apparatus according to claim 23, wherein the signal processor or processing module is configured to determine in the second operating condition an optimum number of pumps which should run for the operating condition, and make a comparison between SE.sub.TOTALn-1 for the pumps 1 to n1 running and SE.sub.TOTALn-2, for the pumps 1 to n2 running based upon the equation:
SE.sub.TOTALn-1<SE.sub.TOTALn-2, where If True, then the second lag pump is re-staged, and If False, then the second lag pump remains de-staged.

25. Apparatus according to claim 19, wherein the signal processor or processing module is configured to determine in a third operating condition if the set point is not being met with all available pumps running, and if so, then de-staging a lag pump is not an option.

26. Apparatus according to claim 1, wherein the apparatus comprises, or takes the form of, the multiple pump system having multiple pumps for arranging or configuring in the multiple pump combinations.

27. A method comprising: receiving in a signal processor or processing module signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system, and also about corresponding system energy consumption related to corresponding multiple pump combinations for staging or destaging a pump in the multiple pump system; determining in the signal processor or processing module corresponding signaling containing information about whether to stage or de-stage the pump in the multiple pump system, based upon a comparison of the system energy consumption and the corresponding system energy consumption and the signaling received; and implementing in the signal processor or processing module to implement control logic or a control logic algorithm and determining if the multiple pump system is operating normally, based upon at least the following three conditions:
PV.sub.ACT=Set Point,
Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<BEP Limit Ratio, and
P.sub.ACT<P.sub.RTDSF, where PV.sub.ACT is an Actual Process Variable received from one or more sensors located on the pump: Set Point is a setting related to flow and pressure for the multiple pump system; Q=Q.sub.CALC or Q.sub.AVG, in which Q.sub.CALC is a calculated Flow for pump n, Q.sub.AVG is an average Dump flow, and Q.sub.AVG being Q.sub.FM/n for Q.sub.FM is the flow meter reading and n is the number of pumps running; Q.sub.BEP is a Best Efficiency Flow at a rated pump speed; N.sub.ACT is an Actual Pump Speed; N.sub.RTD is a Rated Pump Speed: P.sub.ACT is an Actual Pump Power; P.sub.RTD is a Motor Rating; and SF represents a motor service factor.

28. A method according to claim 27, wherein the method comprises providing with the signal processor or processing module the corresponding signaling as control signaling to stage or de-stage the pump in the multiple pump system.

29. A method according to claim 27, wherein the method comprises implementing with the signal processor or processing module control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of specific energy that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system.

30. A method according to claim 29, wherein the method comprises determining with the signal processor or processing module the specific energy of current pumps running and an effect on a total system specific energy of adding another pump to meet process demands related to the multiple pump system.

31. Apparatus comprising: means for receiving in a signal processor or processing module signaling containing information about system energy consumption related to multiple pump combinations running in a multiple pump system, and also about corresponding system energy consumption related to corresponding multiple pump combinations for staging or destaging a pump in the multiple pump system; means for determining in the signal processor or processing module corresponding signaling containing information about whether to stage or de-stage a pump in the multiple pump system, based upon a comparison of the system energy consumption and the corresponding system energy consumption and the signaling received; and means for implementing in the signal processor or processing module to implement control logic or a control logic algorithm and determining if the multiple pump system is operating normally, based upon at least the following three conditions:
PV.sub.ACT=Set Point,
Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<BEP Limit Ratio, and
P.sub.ACT<P.sub.RTDSF, where PV.sub.ACT is an Actual Process Variable received from one or more sensors located on the pump; Set Point is a setting related to flow and pressure for the multiple pump system; Q=Q.sub.CALC or Q.sub.AVG, in which Q.sub.CALC is a calculated Flow for pump n, Q.sub.AVG is an average pump flow, and Q.sub.AVG being Q.sub.FM/n for Q.sub.FM is the flow meter reading and n is the number of pumps running; Q.sub.BEP is a Best Efficiency Flow at a rated pump speed; N.sub.ACT is an Actual Pump Speed; N.sub.RTD is a Rated Pump Speed; P.sub.ACT is an Actual Pump Power; P.sub.RTD is a Motor Rating; and SF represents a motor service factor.

32. Apparatus according to claim 31, wherein the apparatus comprises means for providing with the signal processor or processing module the corresponding signaling as control signaling to stage or de-stage the pump in the multiple pump system.

33. Apparatus according to claim 31, wherein the apparatus comprises, or takes the form of, the multiple pump system having multiple pumps for arranging or configuring in the multiple pump combinations.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The drawing includes the following Figures:

(2) FIG. 1 is a block diagram of apparatus according to some embodiments of the present invention.

(3) FIG. 2 shows a flow chart for a method having steps for optimized staging in a four pump system, according to some embodiments of the present invention.

(4) FIG. 2a shows a key having parameters, notes and rules related to various steps in the flowchart shown in FIG. 2.

(5) FIG. 3 shows a flow chart for a method having steps for optimized de-staging in a four pump system, according to some embodiments of the present invention.

(6) FIG. 3a shows a key having parameters, notes and rules related to various steps in the flowchart shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1: The Basic Apparatus 10

(7) FIG. 1 shows apparatus generally indicated as 10 for implementing some embodiments of the present invention.

(8) By way of example, the apparatus 10 may include, or take the form of, a signal processor or processing module 10a for implementing signal processing functionality associated with the present invention. In operation, the signal processor or processing module 10a may be configured at least to: receive signaling S containing information about system energy consumption related to multiple pump combinations running in a multiple pump system generally indicated as 12; and determine whether to stage or de-stage a pump in the multiple pump system 12, based at least partly on the signaling S received.

(9) In FIG. 1, the apparatus 10 may include other circuits, components or modules 10b, e.g., arranged between the multiple pump system 12 and the signal processor or processing module 10a. The other circuits, components or modules 10b may be configured to cooperate with the signal processor or processing module 10a in order to implement the signal processing functionality of the signal processor or processing module 10a. The other circuits, components or modules 10b may include, e.g., memory modules, input/output modules, data and busing architecture and other signal processing circuits, wiring or components. By way of example, an output module that forms part of the components or modules 10b may be configured to exchange the signaling S with the signal processor or processing module 10a.

(10) The signal processor or processing module 10a is arranged in relation to n pumps labeled 12a, 12b, 12c and 12d respectively, including pump1, pump2, pump3, . . . and pumpn, in the multiple pump system 12. By way of example, the components or modules 10b and the n pumps 12a, 12b, 12c and 12d may be configured to exchange associated signaling, e.g., having reference labels S.sub.1, S.sub.2, S.sub.3, . . . , S.sub.n respectively as shown. The signaling S containing information about the system energy consumption related to the multiple pump combinations may form part of the associated signal S.sub.1, S.sub.2, S.sub.3, . . . , S.sub.n exchanged.

(11) The signal processor or processing module 10a may be configured to provide corresponding signaling containing information about whether to stage or de-stage one or more of the n pumps 12a, 12b, 12c and 12d in the multiple pump system 12. By way of example, the corresponding signaling provided may form part of the exchange of signaling S between the components or modules 10b and the signal processor or processing module 10a, as well as the signal exchange S.sub.1, S.sub.2, S.sub.3, . . . , S.sub.n between the components or modules 10b and the n pumps 12a, 12b, 12c and 12d. Embodiments are envisioned in which the corresponding signaling is provided via either a hard wiring signal exchange and/or a wireless signal exchange.

(12) According to some embodiments, the apparatus 10 may include, or take the form of, e.g. the signal processor or processing module 10a alone or in combination with the components or modules 10b and/or the one or more n pumps 12a, 12b, 12c and 12d in the multiple pump system 12.

(13) According to some embodiments, and by way of example, the signal processor or processing module 10a may be configured with control logic or a control logic algorithm to implement signal processing functionality, as follows:

(14) The signal processor or processing module 10a may be configured to implement control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of specific energy, e.g., that is a measure of energy used per unit mass for the multiple pump combinations running in the multiple pump system 12.

(15) The signal processor or processing module 10a may be configured to determine the specific energy of current pumps running and the effect on the total system specific energy of adding another pump to meet process demands related to the multiple pump system 12.

(16) The signal processor or processing module 10a may be configured in one case to make a comparison between two calculated values of system specific energy; and to choose a pump combination either having a lesser value for staging, or having a greater value for de-staging.

(17) The signal processor or processing module 10a may be configured in another case to evaluate and determine, e.g. not to consider for selection, any pump in a pump combination having a power value which exceeds a nameplate motor rating multiplied by a pre-selected service factor and/or a flow value which exceeds a predetermined BEP Limit Ratio.

(18) The signal processor or processing module 10a may be configured to stage automatically an additional pump, e.g., if either of the aforementioned cases occurs prior to calculating the system specific energy.

(19) The signal processor or processing module 10a may be configured as, or forms part of, at least one variable speed drive with embedded control logic or a control logic algorithm to optimize the staging or de-staging of pumps in the multiple pump system, e.g., including with the use of additional external inputs, such as from a flow meter.

(20) The signal processor or processing module 10a may be configured with control logic or a control logic algorithm that utilizes calculated flow data that is mathematically determined from various pump and motor parameters, including speed, torque or power or from calibrated flow curves, e.g., stored in an evaluation or memory device that may form part of the components or modules 10b.

(21) The signal processor or processing module 10a may be configured with control logic or a control logic algorithm that uses any drive parameter that has a direct relationship to pump flow, including but not limited to the drive parameter disclosed herein. The scope of the invention is also intended to include other drive parameters that are either now known in the art or later developed in the future.

(22) The signal processor or processing module 10a may be configured to implement control logic or a control logic algorithm based at least partly on the system energy consumption taking the form of one or more relative measures of pumping efficiency, e.g., including flow economy which is substantially equal to flow/wire-water power or total system wire-water power, if a flow value is unavailable.

(23) Pumps like elements 12a, 12b, 12c, 12d are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof.

(24) According to some embodiments, the present invention may also include, or take the form of, a method featuring steps for receiving in the signal processor or processing module 10a signaling containing information about system energy consumption related to multiple pump combinations running in the multiple pump system 12; and determining in the signal processor or processing module 10a whether to stage or de-stage a pump in the multiple pump system 12, based at least partly on the signaling received, consistent with that disclosed herein, including that shown in the flow charts in FIGS. 2 and 3 and described below.

FIGS. 2-3: Examples of Control Logic or Control Logic Algorithms for Implementing Staging or De-Staging of One or More Pumps

(25) In particular, and by way of example, FIGS. 2 and 3 show particular examples of flow charts having steps for implementing control logic or control logic algorithms for staging and de-staging of one or more pumps in a multiple pump system like element 12 in FIG. 1.

(26) According to some embodiments of the present invention, the control logic or a control logic algorithm associated with the present invention may be implemented, based at least partly on using parameters, variable frequency drive (VFD) signals and calculated values, as following:

(27) The parameters may include at least the following: Maximum Pump Speed, N.sub.MAX Minimum Pump Speed, N.sub.MIN Rated Pump Speed, N.sub.RTD Best Efficiency Flow at rated pump speed, Q.sub.BEP Motor Rating, P.sub.RTD Low Limit %, applies to synchronous speed (N.sub.ACT/N.sub.RTD%) or synchronous torque (T.sub.ACT%). If the speed or torque % is below the Low Limit % then a lag pump is automatically de-staged. The purpose of this parameter is to limit the low end operating range when multiple pumps are running together to a value greater than minimum speed, N.sub.MIN. Typically multiple pumps do not operate below 50% rated speed.

(28) The VFD signals may include at least the following: Actual Pump Speed, N.sub.ACT Actual Pump Torque, T.sub.ACT Actual Wire to Water Power, kW.sub.W-W (includes power losses in VFD, motor and pump) Actual Process Variable, PV.sub.ACT Actual Pump Power, P.sub.ACT

(29) The calculated values may include at least the following: Calculated Flow for pump n, Q.sub.CALC, GPM Calculated Specific Energy for Pump n, SE.sub.n Calculated System Specific Energy, SE.sub.TOTAL Calculated QR, Pump Flow Ratio, Where QR=Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD) and Q=Q.sub.CALC or Q.sub.AVG. If a flow meter is used Q.sub.AVG=Q.sub.FM/n, where Q.sub.AVG is the average pump flow, Q.sub.FM is the flow meter reading, and n is the number of pumps running. Calculated System Total Wire to Water Power, PT.sub.W-W Note if a flow value is unavailable, then PT.sub.W-W can be substituted in the control logic for SE.sub.TOTAL, where PT.sub.W-W=kW.sub.W-W1+kW.sub.W-W2+kW.sub.W-W3+kW.sub.W-Wn

(30) Further, according to some embodiments of the present invention, the control logic or a control logic algorithm associated with the present invention may be implemented, based at least partly on the following:

(31) 1) The control logic or control logic algorithm may utilize calculated flow data which can be mathematically determined from various pump and motor parameters such as speed, torque or power or from calibrated flow curves stored in an evaluation device. In practice however, this logic could be attempted using any drive parameter that has a direct relationship to pump flow. While the logic stresses the functionality without additional external inputs, a direct reading of flow from a flow meter could also be used.

(32) 2) Where calculated flow or actual flow may not be available, total system power (wire to water) can be substituted for total system specific energy in the evaluation device. Further, the invention is not intended to be limited to one mathematical definition of system energy consumption, e.g., such as specific energy. The scope of the invention is intended to include, and embodiments are envisioned in which other relative measures of pumping efficiency can also be used in the control logic or control logic algorithm, e.g., such as flow economy which is equal to flow/wire-water power, within the spirit of the underlying invention.

FIG. 2: Optimized Staging

(33) By way of example, FIG. 2 shows a flow chart having steps labeled 20a through 20t for implementing optimized staging, e.g., in a four pump system.

(34) The optimized staging process may begin as follows:

(35) The lead pump may be initially started either manually or by waking-up from a sleep condition after process demand has been re-established.

(36) If the PV.sub.ACT=Set Point and Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<BEP Limit Ratio and P.sub.ACT<P.sub.RTDSF, then the system may be determined to be operating normally.

(37) (Note 1.10 is determined to be the default for the BEP Limit Ratio. A calculated value greater than 1.10 is determined to be an indication that the pump may be operating with too much flow. The BEP Limit Ratio can be modified up or down to suit the application.)

(38) The term SF represents a motor service factor (normally 1.0) it also can be modified to suit the application. The equation P.sub.ACT<P.sub.RTDSF is determined to be an indication as to whether the motor may be overloading.

(39) The signal processor or processing module 10a may be configured with a staging control logic or control logic algorithm that evaluates three conditions:

(40) Condition Normal,

(41) Condition 1 and

(42) Condition 2, consistent with that described below.

Condition Normal

(43) If all three of the following conditions are true, then the pump may be determined to be operating normally, including:
PV.sub.ACT=set point,
Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<1.10, and
the P.sub.ACT<P.sub.RTDSF.

Condition 1

(44) When condition normal exists, the specific energy may be calculated and saved for the lead pump by the equation:
SE=kW.sub.W-W/(Q60)=kWHr/G
SE.sub.TOTAL 1=SE.sub.PMP1

(45) Lag pump #1 may be then staged, and after condition normal is determined to be reached, the total system SE may be calculated for the lead pump and lag pump #1 as follows:
SE.sub.TOTAL2=SE.sub.PMP1+SE.sub.PMP2

(46) To determine the optimum number of pumps which should run for the operating condition, a comparison may be made between SE.sub.TOTAL2 (lead and lag running) and SE.sub.TOTAL1 (lead only running):
SE.sub.TOTAL2<SE.sub.TOTAL1

(47) If True, then Lag pump #1 remains staged.

(48) If False, then lag pump #1 de-stages.

Condition 2

(49) If either: The BEP Limit Ratio and/or motor power requirement are false (even if PV.sub.ACT=Set Point), or PV.sub.ACT<set point and the current operating speed, N.sub.ACT is >=0.98N.sub.MAX, then the lag pump #1 will also be staged. In other embodiments, the value of 0.98 can be adjusted to suit the application.
(Note in the above scenario if condition 2 exists then an SE value may not be not calculated when the lead pump only is running. If the PV value is determined not to be meeting the set point with only one pump running, or if operating too far out in flow or overloading the motor, then operating one pump only may be determined no longer to be an option.)

(50) In this case, the lag pump #1 may be staged, and the SE.sub.TOTAL2 may be calculated and saved once condition normal is determined to be reached. Next, lag pump #2 may be staged, and SE.sub.TOTAL3 may be calculated once condition normal is determined to be reached,

(51) Where:
SE.sub.TOTAL3=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3.

(52) To determine the optimum number of pumps which should run for the operating condition, a comparison may be made between SE.sub.TOTAL3 (lead, lag#1 and lag#2 running) and SE.sub.TOTAL2 (lead and lag #1 running):
SE.sub.TOTAL3<SE.sub.TOTAL2

(53) If True, then Lag pumps #1 and #2 remain staged.

(54) If False, then lag pump #2 de-stages

(55) If the set point changes +5% or more and/or the speed changes +10% or more due to a system change, then the SE evaluation may be performed again. In another embodiment these values can be adjusted as required.

(56) The scope of the invention is intended to include the above control logic for staging pumps applying to multiple pump systems having any number of pumps. In other words, the scope of the invention is intended to include implementations in multiple pump systems having more or less than 4 pumps.

FIG. 3: Optimized De-Staging

(57) By way of example, FIG. 3 shows a flow chart having steps labeled 30a through 20z for implementing optimized de-staging, e.g., in a four pump system.

(58) The optimized de-staging process may begins as follows:

(59) By way of example, all four pumps are running and the set point may be lowered at least 5% or a system change occurs resulting in at least a 10% speed change. In another embodiment, these threshold values can be adjusted to suit the application.

(60) Once the reduced set point is determined to be achieved, and PV.sub.ACT=Set Point and Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<BEP Limit Ratio and P.sub.ACT<P.sub.RTDSF, the system is determined to be operating normally.

(61) (Note 1.10 is determined to be the default for the BEP Limit Ratio. A calculated value greater than 1.10 is determined to be an indication that the pump is determined to be operating with too much flow. The BEP Limit Ratio can be modified up or down to suit the application.)

(62) The term SF represents a motor service factor (normally 1.0) it also can be modified to suit the application. The equation P.sub.ACT<P.sub.RTDSF is determined to be an indication as to whether the motor may be overloading.

(63) The signal processor or processing module 10a may be configured with a de-staging control logic or control logic algorithm that evaluates four conditions:

(64) Condition Normal,

(65) Condition 1,

(66) Condition 2 and

(67) Condition 3, consistent with that described below.

Condition Normal

(68) If all three of the following conditions are true, then the pump may be determined to be operating normally, including:
PV.sub.ACT=set point,
Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<1.10, and
the P.sub.ACT<P.sub.RTDSF.

Condition 1

(69) Assuming the set point change results in the speed (N.sub.ACT/N.sub.RTD%) or torque (T.sub.ACT %) value being above the Low Limit % when condition normal exists, then the specific energy may be calculated and saved for the lead pump and lag pumps #1, #2 and #3 by the equation:
SE=kW.sub.W-W/(Q60)=kWHr/G
SE.sub.TOTAL4=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3+SE.sub.PMP4

(70) The Lag pump #3 (SE.sub.PMP4) may be then de-staged, and after condition normal is determined to be reached, the total system SE may be calculated for the lead pump, lag pump #1 and lag pump #2 as follows:
SE.sub.TOTAL3=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3.

(71) To determine the optimum number of pumps which should run for the operating condition, a comparison may be made between SE.sub.TOTAL4 (lead, lags #1, #2 and #3 running) and SE.sub.TOTAL3 (lead, lags #1 and #2 running):
SE.sub.TOTAL4<SE.sub.TOTAL3

(72) If True, then re-stage lag #3.

(73) If False, then lag pump #1 and #2 remain on (lag #3 remains de-staged) and the pump system regulates normally.

Condition 2

(74) If the set point change results in the speed (N.sub.ACT/N.sub.RTD%) or torque (T.sub.ACT%) value being below the Low Limit %, then Lag pump #3 will automatically de-stage, and once condition normal is determined to be reached, the specific energy may be calculated for SE.sub.TOTAL3 (Lead, Lag#1 and lag#2).
SE.sub.TOTAL3=SE.sub.PMP1+SE.sub.PMP2+SE.sub.PMP3

(75) Lag pump #2 may then be de-staged, and after condition normal is determined to be reached, the total system SE may be calculated for the lead pump and lag pump #1 as follows:
SE.sub.TOTAL2=SE.sub.PMP1+SE.sub.PMP2.

(76) To determine the optimum number of pumps which should run for the operating condition, a comparison may be made between SE.sub.TOTAL3 (lead, lags #1 and #2 running) and SE.sub.TOTAL2 (lead and #1 running):
SE.sub.TOTAL3<SE.sub.TOTAL2

(77) If True, then re-stage lag #2.

(78) If False, then lag pump #1 remains on (lags #2 and #3 remain de-staged) and the pump system regulates normally.

(79) (Note, if after de-staging lag pump #3 if either the BEP Limit Ratio (Q/(Q.sub.BEPN.sub.ACT/N.sub.RTD)<1.10), or motor power requirement (P.sub.ACT<P.sub.RTDSF) is determined to be false, then lag pump #3 may be re-staged (even if PV.sub.ACT=Set Point). This condition may occur if pump performance varies significantly from pump to pump. In this case the Low Limit % should be set to a lower value.)

(80) (Note 1.10 is determined to be the default for the BEP Limit Ratio. A calculated value greater than 1.10 is an indication that the pumps are operating with too much flow. The BEP Limit Ratio can be modified to suit the application. The equation P.sub.ACT<P.sub.RTDSF is determined to be an indication as to whether the motor may be overloading. The term SF represents a motor service factor (normally 1.0) it also can be modified to suit the application.)

Condition 3

(81) In the above example when the lead pump and all lag pumps are running (SE.sub.TOTAL4) if PV.sub.ACT<set point and the current operating speed, N.sub.ACT, is >=0.98N.sub.MAX, then no pumps are de-staged.

(82) (Note in the above scenario if condition 3 exists then an SE value is determined not to be calculated. If the set point is determined not to being met with all available pumps running; de-staging a pump is determined not to be an option. In other embodiments, the value of 0.98 can be adjusted as required.)

(83) If the set point changes by at least 5% and/or the speed changes by at least 10% due to a system change the SE evaluation is determined to be performed again. In another embodiment these values can be adjusted as required.

(84) The scope of the invention is intended to include the above control logic for de-staging pumps applying to multiple pump systems having any number of pumps. In other words, the scope of the invention is intended to include implementations in multiple pump systems having more or less than 4 pumps.

One Implementation of Signal Processor 10a

(85) Consistent with that described above, and by way of example, the functionality of the signal processor 10a may be implemented with one or more modules using hardware, software, firmware, or a combination thereof. In a typical software implementation, the one or more modules that form part of the signal processor 10a would include 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 appreciate and 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 some combination of hardware, software, or firmware technology either now known or later developed in the future.

The Signal Processor 10a as a Chipset

(86) In some embodiments according to the present invention, one or more modules of the signal processor 10a may also form part of a basic chipset implementation. The present invention may also take the form of the chipset that may include a number of integrated circuits designed to perform one or more related functions, including a chipset or chip formed as a group of integrated circuits, or chips, that are designed to work together. For example, one chipset may provide the basic functions of the overall controller, while another chipset may provide control processing unit (CPU) functions for a computer or processor in overall controller. Newer chipsets generally include functions provided by two or more older chipsets. In some cases, older chipsets that required two or more physical chips can be replaced with a chipset on one chip. The term chipset is also intended to include the core functionality of a motherboard in such a controller.

Possible Applications

(87) Possible applications may include: Systems having multiple pumps which work together to achieve a process set point. These systems can operate in either synchronous speed or synchronous torque. Additionally, this logic can also be applied in similar systems using fans. The logic employed in these systems can be embedded in various types of controllers such as variable speed drives (VFD), programmable logic controllers (PLC), distributive control systems (DCS) and SCADA systems

The Scope of the Invention

(88) 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.

(89) 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.