CN101033744B

CN101033744B - Method and apparatus for pump protection without the use of traditional sensors

Info

Publication number: CN101033744B
Application number: CN200710001543.5A
Authority: CN
Inventors: 安东尼·A·斯塔瓦莱; 尼古拉斯·W·甘宗
Original assignee: ITT Manufacturing Enterprises LLC
Current assignee: ITT Manufacturing Enterprises LLC
Priority date: 2006-03-08
Filing date: 2007-01-05
Publication date: 2013-07-24
Anticipated expiration: 2027-01-05
Also published as: CN101033744A; DE102007009301B4; DE102007009301A1; FI20070180L; FI20070180A7; FI20070180A0

Abstract

The present invention provides protection for centrifugal pumps while distinguishing between hazardous operating conditions (such as dry running, minimum flow and overload) and/or conditions where transients may occur (such as valve closed operation) and removing protection once these conditions clear. The method makes use of calculated flow values which can be obtained from a calibrated valve closing power versus speed curve and/or for example speed, torque, power and/or differential pressure stored in the evaluation device. Various pump and motor parameters are either determined mathematically through calibrated flow curves. The calculated flow values are then compared to flow thresholds associated with these adverse operating conditions.

Description

Do not use the pump guard method and the equipment of traditional sensors

The cross reference of related application

The title that present patent application requires on March 8th, 2006 to submit to is " Method for PumpProtection Without the Use of Traditional Sensors " temporary patent application no.60/780 (911-2.22-1/05GI002), 529 preference, and the title that relates to submission on March 8th, 2006 is " Method For DeterminingPump Flow Withou tTraditional Sensors " temporary patent application no.60//780,546 (911-2.24-1/05GI003).The full content of these two temporary patent applications is introduced the application by reference.

Technical field

The present invention relates to a kind of have comprise the pumping system of centrifugal pump at interior pump; And relate in particular to a kind of pump guard method and equipment that does not use traditional sensors.

Background technique

Other similar devices and defective thereof are as follows:

U.S. Patent No. 7; 080; 508 disclose a kind of method and apparatus that is used to the pump protection of the torque control of mechanical loss compensation; it, wherein provides the control logic of the operational condition that the direct feedback of utilizing torque (perhaps power) and speed do not expect with identification and provides suitable operation to respond to protect driven equipment (centrifugal pump) not to be damaged by with reference to being introduced at this.Described logic can embed in variable speed drive or the programmable logic controller (PLC) (PLC).Yet this technology may be limited to the pump with the constant ascending power curve of condition of closing from valve.These pumps have 2000 usually and reach following specific speed.This method needs manual input power loss, and power loss can not turn to the factor according to the cutting law, to keep validity in wide speed range of operation.

And, below known equipment all do not comprise be used to distinguish the operational condition do not expected not use traditional sensor and/or additional control to each condition logic of control pump suitably.

U.S. Patent No. 6,591,697 disclose and a kind ofly are used to use motor torque to measure the technology of determining flow rate pump, and wherein motor torque measurements provides a kind of torque and speed described with respect to the method for the relation of flow rate pump and use frequency conversion drive (VFD) to adjust the ability of pump duty with the speed of adjusting centrifugal pump.Yet this equipment does not comprise provides the logic that the operational condition of not expecting is protected.The speed of the calibration of described equipment utilization special use to the curve of torque obtaining flow, thereby reduced flexibility during being provided with at the scene.

Authorize U.S. Patent No. 6 to the assignee of present patent application; 464; 464 B2 disclose the method and apparatus of a kind of control pump system, and this system provides a kind of control and pump protection algorithm, has wherein used VFD to regulate flow, pressure or the speed of centrifugal pump.Yet this equipment need use other instruments, and this has increased the cost and the complexity of drive system, has brought potential potential faults and unnecessary cost.

Another kind of known equipment; be the Load Controls (Sturbridge of company; MA) PMP 25 provides a kind of pump protection, and it carries out relevant with various operational conditions (condition of for example dally, valve cutting out) the power reading that obtains by the observation to current of electric intensity and speed then.(seeing patent no.5,930,092 and 5,754,421).Yet the product of Load Controls only is suitable for constant speed applications and can not provides different control to various conditions, and its protectiveness setting only can be carried out " tripping operation " to motor (tripping) or turn-off.

U.S. Patent No. 6,715,996 B2 disclose a kind of method of operating centrifugal pump, the method of under the condition that valve cuts out pump power being sampled at two speed is provided, and the power of determining parasitic drain and calculating other frequency place adjustment is to determine whether to exist the condition that can cause electrical fault.Yet this technology is only protected the zero delivery condition, does not comprise the logic that detects min flow condition (flow is low excessively) or overload condition (flow is too high), and does not also distinguish no demand conditioned disjunction dry run condition.

PCT WO 2005/064167 A1 discloses a kind of quantitative measurment technology, provides to use the power/differential pressure curve of calibration with respect to the method for flow with respect to speed.The data of calibration are stored and compare to determine pump duty with currency.Yet this technology does not comprise the logic that the operational condition of not expecting is provided protection.It also utilizes power/Δ pressure under the some speed that are stored in the assessment apparatus with respect to the calibration curve of flow.This method needs exclusive data with the acquisition flow, thereby has reduced flexibility during being provided with at the scene.

A kind of product of ABB Industry Oy (Helsinki, Finland) provides frequency conversion drive (VFD), and it has the parameter that allows to dispose minimum and maximum torque value and operates outside these parameter areas to prevent load driver (motor).Yet ABB drives the logic be not provided for explaining different operational conditions, do not allow yet convergent-divergent for example pump centrifugal load or when speed reduces, do not consider mechanical loss in the miniature pump yet.

Frequency changing driving system can be configured to utilize flow or pressure switch to discern the operational condition of not expecting.Yet, use additional process switch to increase the cost and the complexity of drive system, brought potential fault point and unnecessary spending.

In addition, in the patentability retrieval of carrying out related to the present invention, obtained following patent.It is summarized as follows:

The open no.2004/0064292 of the U.S. discloses a kind of required centrifugal pump for deep well of optimum rank that keeps.Wherein use torque and speed data to adjust power with respect to rated velocity, and determine rated flow based on disclosed Pump data with the input power and the use pump cutting law of calculating pump.Wherein use cutting law data and disclosed performance to determine pump head, efficient and minimum required inlet head.Accurate method of calculation does not provide.Wherein only shown flow as the function of power and pressure head, and as the efficient and the inlet head of the function of flow.The simple rated output of described method and it is adjusted at rated velocity, and determine flow from disclosed performance data based on the cutting law.Although be extensive use of in pump industry, it not is accurately always that the cutting of pump performance is proofreaied and correct.

Although the open no.2004/0064292 of the U.S. discloses a kind of control system of centrifugal pump, do not relate to and adjusting or calibration steps.This method need be used actual pump test data, brings the risk of introducing than mistake.The U.S. Patent No. 6,709,241 of authorizing the application's assignee discloses a kind of technology that needs the actual performance data input under four sensors and the some speed in frequency conversion drive.Its use traffic sensor (external flow meter) compares with the threshold value with actual flow and minimum discharge, but can not distinguish condition, dry run condition or overload condition that min flow condition, valve are closed.

The open no.2005/0123408 of the U.S. discloses a kind of self-calibration process, determines that pump pressure increases the minimum speed of an increment.But it is not used to calibrate power.The idle running protection is based on actual current reading and the comparison of current threshold is carried out.Threshold value is based on a service speed.

U.S. Patent No. 4,468,219 and No.4,795,314 and the open no.US2002/0141875 of the U.S. a kind of peristaltic pump or positive-displacement pump are disclosed, its behavior is very different with the centrifugal load about torque and speed.

U.S. Patent No. 6,783,328 and open no.2002/0150476 disclosed Technology Need sensor monitoring flow of the U.S. or pressure, so that set-point value and threshold value are compared.If surpass threshold value, then underspeed so that set point is lower than threshold value.

U.S. Patent No. 4,650,633 disclose a kind of method, its based at the sensor of pump intake place test fluid temperature and pressure and the flow of restrictive pump to prevent cavitation.

Based on understanding and evaluation to above-described known prior art; needing in related domain a kind ofly can not need to use the technology of traditional sensor for centrifugal pump provide protection; thereby can distinguish risky operation condition (for example idle running, minimum discharge and overload) and/or the condition (for example valve close operation) of momentary status may take place, in case and these conditions remove then the cancellation protection.

Summary of the invention

The invention provides a kind of new and unique method and apparatus that is used for not using traditional sensor to carry out the pump protection, its by the calculated flow rate value with the motor signal of threshold value flow, speed and the power (perhaps torque) of the curve of the power of closing with respect to valve and for example the following optimum efficiency power of rated pump speed, power that valve cuts out and the pump performance data that disclose substantially of optimum efficiency flow compare from the speed that is stored in the field calibration in the assessment apparatus.Be used for to obtain by various technology with the flow input of the calculating of threshold value flow value comparison, to use pump cutting law data and to be stored in traffic alignment curve and for example pump and the motor signal of speed and power (perhaps torque) or speed and power/differential pressure under the various speed in the assessment apparatus, calculated flow rate.

The control pump method of operating is characterised in that actual flow value and the corrected threshold flow value of proofreading and correct based on pump speed is compared, thereby determines pump operated condition.Based on described comparison, can adapt to pump operated reaction.

The relation that the correction of threshold value flow value is based between actual pump speed and the rated pump speed is carried out.

The threshold value flow value of proofreading and correct can comprise overload condition value (flow is excessive), minimum stream value (flow is too small) or their some combination, and described method can comprise that the overload condition threshold value of will proofread and correct compares with actual overload flow value, thereby determines the overload condition of pump.

Described method can also comprise that minimum discharge threshold value and the actual minimum stream value that will proofread and correct compare, thereby determine or the normal flow rate condition of pump or may be min flow condition, these steps compare minimum discharge threshold value and the actual flow value of proofreading and correct individually or jointly, and the performance number that the valve under actual power value and the current pump speed cuts out compares, thereby determines whether to exist the min flow condition or the dry run condition of pump.Embodiment can also comprise that the proportion to the medium that is sucked has carried out the actual power value of proofreading and correct, performance number or its combination that valve cuts out.

In fact, the threshold value of the flow value of the calculating flow that can be associated with these disadvantageous operational conditions compares.The curve of the power that the current operating value of speed, power or torque can be closed with respect to valve with the speed that is stored in the field calibration in the assessment apparatus and for example the optimum efficiency power under the rated pump speed, power that valve cuts out and the basic openly pump performance data of optimum efficiency flow compare, thereby calculating actual flow, perhaps can compare with respect to power (perhaps torque) or flow calibration curve, thereby determine the actual flow value with the flow that is stored in the assessment apparatus with respect to power/differential pressure.Comprised in installation under the situation of flowmeter, can be used as direct input to pump protection algorithm.Logic can be embedded into frequency conversion drive or programmable logic controller (PLC).

The present invention can also comprise the controller of the module with the set that is configured to realize above-mentioned feature, and the pumping system with described controller.

Among the disclosed embodiment, protection is based on the torque of self-driven measurement and speed to compare with rated output and with the power of calculating and based on the maximum power threshold of cutting law to velocity correction in US2004/0064292.The method according to this invention uses the power of closing by the valve of proofreading and correct to create than the curve of the power that may only use the velocity correction more accurately of cutting law with respect to flow with respect to the flow value of the no sensor of the curve derivation of speed.Flow value and minimum discharge with described no sensor compares with the threshold value of crossing current carrying capacity then.And by the valve power of closing of calibration is checked idle running with the comparison of the actual power under current service speed and the specific gravity.

In fact, the invention provides protection to centrifugal pump, distinguish risky operation condition (for example idle running, minimum discharge and overload) simultaneously and/or may take place transient state condition (for example valve close operation) in case and these conditions remove then the cancellation protection.Described method utilization can be related with these unfavorable operational conditions the flow value of the calculating that compares of the threshold value of flow.The curve of the power that the current operating value of speed, power or torque can be closed with respect to valve with the speed that is stored in the field calibration in the assessment apparatus and for example the optimum efficiency power under the rated pump speed, power that valve cuts out and the basic openly pump performance data of optimum efficiency flow compare, thereby calculated flow rate, perhaps can be stored in the assessment apparatus, compare with respect to power (perhaps torque) or flow calibration curve with the flow of various speed with respect to power/differential pressure.The threshold value of then that the flow value that calculates is related with these unfavorable operational conditions flow compares.

At last, it should be noted that, pump power under the condition that calibrating valve of the present invention is closed is adjusted disclosed performance with the reflection actual performance with respect to speed and based on calibration curve, thereby determines more exactly that than aforementioned announcement 2004/0064292 is disclosed power under the service speed is with respect to flow.

Description of drawings

Fig. 1 is the skeleton diagram according to basic pumping system of the present invention;

Fig. 2 is the flow chart according to the basic step of carrying out by controller shown in Figure 1 of the present invention; And

Fig. 3 is the skeleton diagram of the controller shown in Figure 1 of execution basic step shown in Figure 2.

Embodiment

Fig. 1 shows according to basic pumping system of the present invention, usually is expressed as 2, and it has controller 4, motor 6 and pump 8.In operation, according to controller 4 of the present invention, the motor signal of curve, speed and the power (perhaps torque) of the power that the speed by being stored in the field calibration in the assessment apparatus is closed with respect to valve and the optimum efficiency power under for example described rated pump speed, power that valve cuts out and the basic openly pump performance data of optimum efficiency flow, and determine the flow value that calculates.Described being used for can also obtain by various technology with the flow input of the calculating of threshold value flow value comparison, to use pump cutting law data and to be stored in traffic alignment curve and for example pump and the motor signal of speed and power (perhaps torque) or speed and power/differential pressure under the various speed in assessment apparatus or the module (for example module 4a among Fig. 3), calculated flow rate.Comprise in installation under the situation of flowmeter that it can be as the direct input of pump protection algorithm.

Especially, controller 4 is by the operation of module 4a (see figure 3) control pump 8, and module 4a is configured to actual flow value and threshold value flow value based on the velocity correction of pump 8 are compared, thereby determines pump operated condition.Based on described comparison, can adapt to the operation of pump 8, before this is included in and only gives a warning, in response to described condition, use the user that delay can be set, warning and speed is reduced to safety operation speed reports an error and closes power machine or the mistake and restart pump and whether motor is removed with the inspection condition of automatically reseting.If condition is removed, then cancel this adaptation and pump enabling.Described correction is based on and meets actual pump speed as described below and the relation between the rated pump speed is carried out.

The threshold value flow value of proofreading and correct can comprise overload condition value, minimum stream value or their some combination, and the overload condition threshold value that module 4a can be configured to proofread and correct compares with actual overload flow value, thereby determines the overload condition of pump 8.

Minimum discharge threshold value and actual minimum stream value that module 4a can also be configured to proofread and correct compare, thereby determine or the normal flow rate condition of pump or may be min flow condition, these steps compare minimum discharge threshold value and the actual flow value of proofreading and correct individually or jointly, and the performance number that the valve under actual power value and the current pump speed cuts out compares, thereby determines whether to exist the min flow condition or the dry run condition of pump.Embodiment can also comprise that the proportion to the medium that is sucked has carried out the actual power value of proofreading and correct, performance number or its combination that valve cuts out.

In fact, the threshold value of the flow value of the calculating flow that can be associated with these disadvantageous operational conditions compares.The curve of the power that the current operating value of speed, power or torque can be closed with respect to valve with the speed that is stored in the field calibration in the assessment apparatus and for example the optimum efficiency power under the rated pump speed, power that valve cuts out and the basic openly pump performance data of optimum efficiency flow compare, thereby calculated flow rate, perhaps can be stored among assessment apparatus or the module 4a, compare with respect to power (perhaps torque) or flow calibration curve at the flow at various speed place with respect to power/differential pressure, thereby determine the actual flow value.Comprised in installation under the situation of flowmeter (not shown), can be used as the direct input of the pump protection algorithm of in controller 4, realizing.Control logic can be embedded in the controller of 4a for example, and as shown in the figure, it can have the form of frequency conversion drive (VFD) or programmable logic controller (PLC) (PLC).

Motor 6 and pump 8 are well known in the art, are not described in detail in this.And scope of the present invention is not limited to the current any particular type known or exploitation in the future or the motor and the pump of kind.And scope of the present invention attempts also to comprise that use is according to the relevant technology of operation of the present invention and control centrifugal pump, centrifugal stirrer, centrifugal blower or centrifugal compressor.

In fact; the present invention includes and may be embodied as control logic; this control logic is used to from the direct feedback of power of motor 6 and pump 8 (perhaps torque) and speed and the calculated flow rate value; thereby the operational condition that identification is not expected, and provide suitable operation response not to be damaged with protection machine driven (centrifugal pump).The threshold value of then that the flow value that calculates is related with these unfavorable operational conditions flow compares.Replacedly, the current operating value of speed, power or torque can compare with respect to the power (perhaps torque) or the curve of power/differential pressure with the flow that is stored in the calibration in the assessment apparatus, thereby determines the actual flow value.Replacedly, comprised in installation under the situation of flowmeter, can be used as direct input to pump protection algorithm.

Fig. 2: control logic

Fig. 2 shows in the mode of example and usually is expressed as 10 flow chart, has the basic step 12-18 of pump protection algorithm or the control logic that can realize by controller 4 according to the present invention.Described pump protection algorithm or control logic can be embedded in frequency conversion drive or programmable logic controller (PLC), shown in reference controller in Fig. 14.The mathematical model accurately of the motor that a lot of current VFD system creations are driven is to provide the accurate control to speed and torque.Given this information, protection logic according to the present invention can followingly realize:

Input can comprise:

-minimum speed

-top speed

-rated velocity

Minimum discharge threshold value under the-rated velocity (flow is low excessively)

Overload flow threshold (flow the is excessive) under-rated velocity

-K _DRThe coefficient that-the power of closing with the valve under the current service speed multiplies each other can be used for determining dry run condition.

-guard delay-before announcing protective condition be the time lag of unit with the second.

Based on current service speed, minimum discharge and the following correction of overload flow threshold:

-Q _{MIN_COR}＝Q _MIN×(N _ACT/N _RATED)

-Q _{RO_COR}＝Q _RO×(N _ACT/N _RATED)

Wherein:

Q _{MIN_COR}Minimum discharge for velocity correction

Q _{RO_COR}The current carrying capacity of crossing for velocity correction

N _ACTBe actual velocity

N _RATEDBe rated velocity

In case announced certain condition, then logic depends on to be provided with provides following action:

Overload condition 13

If-actual flow is then announced overload protection condition 13 greater than the overload flow set of velocity correction.

The reaction of-driving is the warning user, and does not take further action.Announcing before the overload condition to be set the guard delay cycle.If overload condition is removed, then the overload warning will be eliminated.

Min flow condition 17

If actual flow is lower than the minimum discharge setting and the P of velocity correction _ACTGreater than K _DR* P _SO_ N then announces minimum discharge protective condition 17,

Wherein:

-K _DRBe the idle running coefficient,

-P _ACTBe the actual power that proportion=1 is proofreaied and correct, and

-P _{SO_N}Be the power that the valve under the present speed of proportion=1 correction cuts out.P _SOTo be the power of closing by the valve that is stored in the assessment apparatus carry out interpolation with respect to the curve of speed to _ N obtains.Replacedly, P _SO_ N can be by the following calculating of cutting law: P _SO_ N=P _So(rated velocity) * (N actual velocity/N rated velocity) ^KSO, wherein KSO is generally equal to 3.0.For the pump of fraction horsepower, can be to K _DRProofread and correct with compensation at the P that uses under the cutting computational methods situation _SOThe inaccuracy of _ N.K then _DRCorr=K _DR* (N actual velocity/N rated velocity) ^0.5And the formula among Fig. 2 becomes P _ACT＜K _DRCorr * P _SO_ N.

-the reaction that drives can be set to warn the user and not take further action, warning user and be reduced to safe minimum operation speed (reporting to the police and control) or report an error and turn-off the unit.Announcing before the min flow condition to be set the guard delay cycle.Whether driving can also be set to automatically reset warning and controlled conditions or report an error is removed with check system transient condition.The number of times that resets and reset between time can adjust by the user.In case number of resets uses up, if condition is not removed, then the unit keeps turn-offing, and manually restarts up to the user.

Dry run condition 18

If P _ACTLess than K _DR* P _SO_ N then announces idle running protective condition 18.

-the reaction that drives can be set to warn the user and not take further action, perhaps reports an error and turn-offs the unit.Announcing before the dry run condition to be set the guard delay cycle.Driving can not be set to the condition of reporting an error that automatically resets.In case the unit reports an error, then keep turn-offing, manually restart up to the user.

Should be noted that scope of the present invention comprises all functions by user selection ground forbidding.

Fig. 3: controller 4

Fig. 3 shows the basic module 4a and the 4b of controller 4.The controller and the control module that are used for the many dissimilar and kind of control pump are well known in the art.Based on understanding to these known controllers and control module, those skilled in the art can realize the control module of 4a for example and it is configured to carry out and to describe the consistent function of content at this, comprise thereby actual flow value and the corrected threshold flow value of proofreading and correct based on pump speed are compared definite pump operated condition, and realize other basic steps of the present invention, for example shown in Figure 2 and above-described process in accordance with the present invention.In the mode of example, can use the function of hardware, software, firmware or its combination realization module 4a, although scope of the present invention is not limited to its any specific embodiment.In typical software is realized, described module can be one or more architecture based on microprocessor, has microprocessor, random access storage device (RAM), ROM (read-only memory) (ROM), input-output apparatus and the control that is connected these assemblies, data and address bus.Those skilled in the art can programme to described realization based on microprocessor not to be needed too much to test to carry out function described here.Scope of the present invention is not limited to the specific implementation of any use technology known or that develop in the future.

The capable territory of controling appliance known other controller modules 4b, it is as a part of the present invention, and is not described in detail at this.

The application that other are possible

1. pump load monitoring device: pump load monitoring device depends on accurate modeling to the pump power curve with identification minimum discharge and turn-off criterion.Although most load monitoring devices only monitor the power under the speed, described logic can be supported the device of load monitoring more accurately to the variable velocity operation.

2. pump is protected algorithm: the flow measurement of no sensor can provide the reliable indication of operational condition: overload condition (flow is excessive) is lower than the operation (flow is low excessively) of minimum pump duty or the operation of closing at expulsion valve.

Scope of invention

Should be appreciated that unless stated otherwise, also can use, use or be included in any other embodiment described here in this any feature of describing with reference to specific embodiment, characteristic, alternative embodiment or modification.And accompanying drawing is not to draw in proportion.

Although reference example embodiment describes and illustrated the present invention, can make various aforementioned interpolation and omissions with other to it, and not deviate from the spirit and scope of the present invention.

Claims

CLAIMS 1. A method for controlling the operation of a pump comprising a centrifugal pump, a centrifugal mixer, a centrifugal blower or a centrifugal compressor comprising:

Deriving the actual flow value determined without the use of a sensor from a calibration curve of speed versus valve closing power;

comparing the actual flow value to a corrected threshold flow value corrected based on the pump speed and related to an undesired operating condition of the pump, thereby determining a pump operating condition; and

The pump is controlled based on a comparison between the derived actual flow value and a corrected threshold flow.

2. The method of claim 1, wherein the method further comprises adapting operation of the pump based on the comparison, including using a user-settable delay in response to the pump operating condition before merely issuing a warning, Warn and reduce speed to safe operating speed, report an error and shut down the motor connected to the pump or automatically reset the error and restart the pump and motor to check if the pump operating condition clears, and if the pump operating condition Cleared, the adaptation is canceled and the pump resumes normal operation.

3. The method of claim 1, wherein the correction is based on a relationship between actual pump speed and nominal pump speed.

4. The method of claim 1, wherein the corrected threshold flow value comprises an overload condition value, a minimum flow value, or a combination thereof.

5. The method of claim 1, wherein the method includes comparing an overload condition value to an actual overload flow value, thereby determining an overload condition of the pump.

6. The method of claim 1, wherein the method includes comparing a corrected minimum flow value to an actual minimum flow value to determine a normal flow condition or a minimum flow condition for the pump.

7. The method of claim 1, wherein the method further comprises comparing the corrected minimum threshold flow value to the actual flow value, and also comparing the actual power value to the valve closed power value at the current pump speed , so as to determine the minimum flow condition or idling condition of the pump.

8. The method of claim 1, wherein the method further comprises comparing the corrected minimum threshold flow value to the actual flow value, and also comparing the actual power value to the valve closed power value at the current pump speed , thereby determining a minimum flow condition or an idle condition of the pump, wherein the valve closed power value is obtained by interpolating a calibrated power versus speed curve stored in a memory device.

9. The method of claim 1 , wherein an idle condition is declared if P _ACT is less than K _DR × P _SO —N , where P _ACT is actual power corrected for specific gravity = 1 and K _DR is relative to current operating speed The valve closing power is multiplied by a factor, and P _SO _N is the valve closing power at the current speed corrected for specific gravity = 1.

10. The method of claim 7, wherein the actual power value, the valve closed power value, or a combination thereof are corrected for the specific gravity of the medium being pumped.

11. The method according to claim 1, wherein the minimum value of the corrected threshold flow value is based on the formula Q _{MIN_COR} = Q _MIN * (N _ACT /N _RATED ), wherein Q _{MIN_COR} is the velocity corrected minimum flow, Q _MIN is the minimum flow, N _ACT is the actual speed, and N _RATED is the rated speed.

12. The method of claim 1, wherein the corrected threshold flow value includes an overload condition value based on a corrected overload flow threshold value based on the formula Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is Speed corrected overload flow, Q _RO is overload flow, N _ACT is actual speed, and N _RATED is rated speed.

13. The method according to claim 1, wherein said actual flow value is calculated by means of a calibrated speed versus valve closing power curve stored in an evaluation device, a motor signal of speed and power, and a pump at rated pump speed The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

14. The method according to claim 1, wherein said actual flow value is calculated by means of a calibrated speed versus valve closing power curve stored in an evaluation device, a motor signal of torque, and the pump speed at rated pump speed. Substantial disclosure pump performance data, wherein the substantive disclosure pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

15. The method of claim 4, wherein the method includes comparing an overload condition value to an actual overload flow value to thereby determine an overload condition of the pump.

16. The method of claim 8, wherein an idle condition is declared if P _ACT is less than K _DR × P _SO —N , where P _ACT is actual power corrected for specific gravity = 1 and K _DR is relative to current operating speed The valve closing power is multiplied by a factor, and P _SO _N is the valve closing power at the current speed corrected for specific gravity = 1.

17. The method of claim 7, wherein the corrected minimum threshold flow value is based on the formula Q _{MIN_COR} = Q _MIN * (N _ACT /N _RATED ), where Q _{MIN_COR} is the velocity corrected minimum flow and Q _MIN is Minimum flow, N _ACT is actual speed, and N _RATED is rated speed.

18. The method of claim 5, wherein the overload condition value is based on the formula Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is the speed corrected overload flow, Q _RO is the overload flow, N _ACT is the actual speed, and N _RATED is the rated speed.

19. The method according to claim 7, wherein said actual flow value is calculated by means of a calibrated speed versus valve closed power curve stored in an evaluation device, a motor signal of speed and power, and a pump at rated pump speed The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

20. The method according to claim 7, wherein said actual flow value is calculated by means of a calibrated speed versus valve closing power curve stored in an evaluation device, a motor signal of torque, and the pump speed at rated pump speed. Substantial disclosure pump performance data, wherein the substantive disclosure pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

21. A controller for controlling the operation of a pump comprising a centrifugal pump, a centrifugal mixer, a centrifugal blower or a centrifugal compressor, comprising:

configured to derive an actual flow value determined without the use of a sensor from a calibration curve relative to speed of valve closing power; and to correlate the actual flow value with a correction based on the pump speed and involving undesired operating conditions of the pump A threshold flow value is compared to determine a pump operating condition; and a module for controlling the pump is based on the comparison between the derived actual flow value and the corrected threshold flow.

22. The controller of claim 21 , wherein the module is configured to adapt operation of the pump based on the comparison, including using a user-settable delay in response to the pump operating condition before merely issuing a warning. , warn and reduce the speed to a safe operating speed, report an error and shut down the motor connected to the pump or automatically reset the error and restart the pump and motor to check that the pump operating condition clears, and when the pump operates If the condition clears, the adaptation is canceled and the pump resumes normal operation.

23. The controller of claim 21, wherein the correction is based on a relationship between actual pump speed and nominal pump speed.

24. The controller of claim 21, wherein the corrected threshold flow value comprises an overload condition value, a minimum flow value, or a combination thereof.

25. The controller of claim 21, wherein the module is configured to compare an overload condition value to an actual overload flow value to determine an overload condition of the pump.

26. The controller of claim 21, wherein the module is configured to compare the corrected minimum flow threshold to an actual minimum flow value to determine either a normal flow condition or a minimum flow condition for the pump.

27. The controller of claim 21, wherein the module is configured to compare the corrected minimum threshold flow value to the actual flow value, and also compare the actual power value to the valve closed power value at the current pump speed comparison, thereby determining the minimum flow condition or the idle condition of the pump.

28. The controller of claim 21, wherein the module is further configured to compare the corrected minimum threshold flow value to an actual flow value, and also to compare the actual power value to the valve closed power value at the current pump speed A comparison is made to determine a minimum flow condition or an idle condition for the pump, wherein the valve closed power value is obtained by interpolating a calibrated power versus speed curve stored in a memory device.

29. The controller of claim 21, wherein an idle condition is declared if P _ACT is less than K _DR ×P _SO —N, where P _ACT is actual power corrected for specific gravity = 1 and K _DR is relative to current operating speed The valve closing power of is multiplied by the coefficient, and P _SO _N is the valve closing power at the current speed corrected for specific gravity=1.

30. The controller of claim 27, wherein the actual power value, the valve closed power value, or a combination thereof is corrected for the specific gravity of the medium being pumped.

31. The controller of claim 27, wherein the minimum corrected threshold flow value is based on the formula Q _{MIN — COR} = Q _MIN * (N _ACT /N _RATED ), where Q _{MIN — COR} is the velocity corrected minimum flow, where Q _MIN is the minimum flow, N _ACT is the actual speed, and N _RATED is the rated speed.

32. The controller of claim 21, wherein the corrected threshold flow value includes an overload condition value based on the corrected overload flow threshold value of Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is the speed corrected overload flow, Q _RO is the overload flow, N _ACT is the actual speed, and N _RATED is the rated speed.

33. The controller of claim 21, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closed power curve stored in an evaluation device, motor signals for speed and power, and rated pump speed Basic public pump performance data under , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

34. The controller of claim 21 , wherein the calculation of the actual flow value is based on a calibrated speed versus valve closing power curve stored in an evaluation device, a motor signal of torque, and a motor signal at rated pump speed. The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

35. The controller of claim 21, wherein the controller is a variable frequency controller or a programmable logic controller.

36. The controller of claim 24, wherein the module is configured to compare an overload condition value to an actual overload flow value to determine an overload condition of the pump.

37. The controller of claim 28, wherein an idle condition is declared if P _ACT is less than K _DR ×P _SO —N , where P _ACT is actual power corrected for specific gravity = 1, and where K _DR is the ratio of current operating speed The coefficient to multiply the valve closed power at , and P _SO _N is the valve closed power at the current speed corrected for specific gravity=1.

38. The controller of claim 28, wherein the corrected minimum threshold flow value is based on the formula Q _{MIN_COR} = Q _MIN * (N _ACT /N _RATED ), Q _{MIN_COR} is the velocity corrected minimum flow, Q _MIN is Minimum flow, N _ACT is actual speed, and N _RATED is rated speed.

39. The controller of claim 25, wherein the overload condition value is a corrected overload flow threshold based on the formula Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is the speed corrected overload flow , Q _RO is the overload flow, N _ACT is the actual speed, and N _RATED is the rated speed.

40. The controller of claim 27, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closed power curve stored in an evaluation device, motor signals for speed and power, and rated pump speed Basic public pump performance data under , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

41. The controller of claim 27, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closing power curve stored in an evaluation device, a motor signal of torque, and The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

42. A centrifugal pump system having a controller for controlling the operation of a pump comprising a centrifugal pump, a centrifugal mixer, a centrifugal blower or a centrifugal compressor, the controller comprising:

43. The pump system of claim 42, wherein the module is configured to adapt operation of the pump based on the comparison, including using a user-settable delay in response to the pump operating condition before only issuing a warning. , warn and reduce the speed to a safe operating speed, report an error and shut down the motor connected to the pump or automatically reset the error and restart the pump and motor to check that the pump operating condition clears, and if the pump operates If the condition clears, the adaptation is canceled and the pump resumes normal operation.

44. The pump system of claim 42, wherein the correction is based on a relationship between actual pump speed and nominal pump speed.

45. The pump system of claim 42, wherein the corrected threshold flow value comprises an overload condition value, a minimum flow value, or a combination thereof.

46. The pump system of claim 42, wherein the module is configured to compare an overload condition value to an actual overload flow value to determine an overload condition of the pump.

47. The pump system of claim 42, wherein the module is configured to compare the corrected minimum flow threshold to an actual minimum flow value to determine either a normal flow condition or a minimum flow condition for the pump.

48. The pump system of claim 42, wherein the module is configured to compare the corrected minimum threshold flow value to the actual flow value, and also compare the actual power value to the valve closed power value at the current pump speed comparison, thereby determining the minimum flow condition or the idle condition of the pump.

49. The pump system of claim 42, wherein the method further comprises comparing the corrected minimum threshold flow value to the actual flow value, and also comparing the actual power value to the valve closed power value at the current pump speed comparison to determine a minimum flow condition or an idle condition of the pump, wherein the valve closed power value is obtained by interpolating a calibrated power versus speed curve stored in a memory device.

50. The pump system of claim 42, wherein a dry run condition is declared if P _ACT is less than K _DR ×P _SO —N , where P _ACT is actual power corrected for specific gravity = 1 and K _DR is relative to the current operating speed The valve closing power is multiplied by a factor, and P _SO _N is the valve closing power at the current speed corrected for specific gravity = 1.

51. The pump system of claim 42, wherein the actual power value, the valve closed power value, or a combination thereof is corrected for the specific gravity of the medium being pumped.

52. The pump system of claim 49, wherein the corrected minimum threshold flow value is based on the formula Q _{MIN_COR} = Q _MIN * (N _ACT /N _RATED ), where Q _{MIN_COR} is the velocity corrected minimum flow, Q _MIN is the minimum flow, N _ACT is the actual speed, and N _RATED is the rated speed.

53. The pump system of claim 42, wherein the corrected threshold flow value includes an overload condition value based on the corrected overload flow threshold value of the formula Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is the speed corrected overload flow, Q _RO is the overload flow, N _ACT is the actual speed, and N _RATED is the rated speed.

54. The pump system of claim 42, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closed power curve stored in an evaluation device, a motor signal for speed and power, and a rated pump speed Basic public pump performance data under , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

55. The pump system of claim 42, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closing power curve stored in the evaluation device, a motor signal of torque, and The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

56. The pump system of claim 42, wherein the controller is a variable frequency controller or a programmable logic controller.

57. The pump system of claim 45, wherein the module is configured to compare an overload condition value to an actual overload flow value to determine an overload condition of the pump.

58. The pump system of claim 49, wherein a dry run condition is declared if P _ACT is less than K _DR ×P _SO —N , where P _ACT is actual power corrected for specific gravity = 1 and K _DR is The valve closing power of is multiplied by the coefficient, and P _SO _N is the valve closing power at the current speed corrected for specific gravity=1.

59. The pump system of claim 48, wherein the actual power value, valve closed power value, or a combination thereof is corrected for the specific gravity of the medium being pumped.

60. The pump system of claim 48, wherein the corrected minimum threshold flow value is based on the formula Q _{MIN_COR} = Q _MIN * (N _ACT /N _RATED ), where Q _{MIN_COR} is the velocity corrected minimum flow, Q _MIN is the minimum flow, N _ACT is the actual speed, and N _RATED is the rated speed.

61. The pump system of claim 46, wherein the overload condition value is a corrected overload flow threshold based on the formula Q _{RO — COR} = Q _RO × (N _ACT /N _RATED ), where Q _{RO — COR} is the velocity corrected overload flow , Q _RO is the overload flow, N _ACT is the actual speed, and N _RATED is the rated speed.

62. The pump system of claim 48, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closed power curve stored in an evaluation device, a motor signal for speed and power, and a rated pump speed Basic public pump performance data under , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.

63. The pump system of claim 48, wherein the calculation of the actual flow value is based on a calibrated speed versus valve closing power curve stored in the evaluation device, a motor signal of torque, and The basic public pump performance data of , wherein the basic public pump performance data is optimal efficiency power, valve closed power, and optimal efficiency flow.