DE102007010768A1 - Regulator for regulating operation of e.g. centrifugal pump, has module to determine flow acquisition data based on different pump- and motor parameters such as number of revolutions, torque and efficiency, from calibrated flow curves - Google Patents

Abstract

The regulator (4) has a determining module to determine flow acquisition data based on different pump- and motor parameters such as number of revolutions, torque and efficiency, from calibrated flow curves stored in an evaluation device or an external flow acquisition device e.g. flow meter. A regulating module regulates a pump (8), a rotary axial blower, a rotary mixer or a radial compressor in a valve system with proportional-integral-derivative (PID) regulation by using the flow acquisition data. An independent claim is also included for a method of optimization of a valve position and a pump rotation speed in a valve system.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

These Patent application claims the priority of a provisional patent application under reference 60 / 780,547, filed on 8 March 2006, which is hereby incorporated by reference in its entirety.

These Patent application also relates to the patent application, and claims priority to No. 11 / 636,355 (05GI003US / 911-2.24-2) filed on 8 December 2006 under the title "Method for determining pump flow without the use of traditional sensors ", as well as the patent application under the reference 11 / 601,373 (05GI002 / 911-2.22-2) under the Title "Method and Apparatus for Pump Protection Without the Use of Traditional Sensors ", filed on November 17, 2006, both of which are hereby incorporated by reference be included in their entirety.

BACKGROUND THE INVENTION

1st area the invention

The The present invention relates to a pump including a Centrifugal pump, more particularly to a method and apparatus for optimizing the valve position and the pump speed in a valve system with PID control without the use of external signals.

2. Short description the related art

Other similar devices and their disadvantages are as follows:
PCT WO 2005/064167 A1 entitled "Quantitative Measurement" by Witzel, Rolf et al., Discloses a methodology using a calibrated curve for power versus differential pressure against flow versus speed, the calibrated data being stored and updated with current values However, while this method can monitor pump performance and differential pressure data to predict flow due to a calibrated pump curve at various speeds, it can not seek optimal pump speed and valve position from a PID control valve system.

United United States Patent No. 6,591,697, Henyan, entitled "Method For Determining Pump Flow Rates Using Motor Torque Measurements "sets out a methodology open, showing the relationship of torque and speed to pump flow rate and the possibility explained, the pump flow with a frequency converter drive (VFD) for Adjusting the centrifugal pump speed to regulate. While it possible with this method is the relationship of torque and speed to pump flow rate to monitor and pump flow using a frequency converter drive (VFD) to adjust the centrifugal pump speed can There is no optimal pump speed and valve position from a valve system with Search for PID control.

United United States Patent No. 6,464,464 B2, Sabini et al. granted, under the Title "Apparatus and Method for Controlling a Pump System "discloses a methodology that includes a Control and pump protection algorithm explained using a VFD regulates the flow, pressure or speed of a centrifugal pump. While This method uses flow or pressure through a PID loop, which embedded in a frequency converter drive (VFD) by feedback signals can regulate from an external transmitter, it can not be optimal Speed and control valve position from a valve system with PID control search.

SUMMARY THE INVENTION

in the broadest sense, the present invention has a method and Devices for determining flow reference data as a function of various pump and motor parameters such as speed, torque or power, or from calibrated flow curves, in one evaluation unit stored or from an external flow reference unit as a flow meter, and to use the flow reference data with the target, a centrifugal pump, a radial fan, a centrifugal mixer or a centrifugal compressor in a valve system with PID control too regulate. The device may act as a regulator or other suitable processing device be executed to control the operation of the pump.

The overcomes the present invention So disadvantages of the above equipment according to the state of the art for Pumping systems using a PID control valve logic control the process in which the input of valve data / position or other external signals is not desirable. The algorithm according to the present Invention operates with flow reference data dependent from the various pump and motor parameters such as speed, Torque or power or from calibrated flow curves, in the evaluation device stored or from the external flow reference unit How a flowmeter can be determined mathematically.

Embodiments of the present invention may include one or more of the following features As soon as the valve with PID control has reached its static normal state, a calculated flow value can be detected and compared with the current flow value obtained after the frequency (speed) of the frequency inverter drive has dropped. For pressure control applications, the valve position can be optimized if the current flow rate is within 90 - 110% of the pump's optimum flow rate at current speed. A final check Can be performed on a wide open control valve by increasing the pump speed by a set amount and comparing the current flow value with a stored flow value; if the flow does not increase, the valve position is optimized. If the controller has already reached its optimized state and either the actual engine torque increases by 5% or more, or the actual flow increases by more than 5% or more, the valve optimization process can be restarted at maximum speed. Alternatively, if the controller has already reached its optimized state and either the actual engine torque decreases by 5% or more, or the actual flow rate decreases by 5% or more, the valve optimization process may be restarted at the current operating point. A user-selectable secondary test on a wide open valve may be performed to determine whether a change in actual engine torque is 2% or more but less than 5% of the optimized state for the duration of the response delay; if this condition is true and the actual flow is greater than the optimized flow value after a one-step change in speed, the optimization process can be restarted at maximum speed. In addition, the valve position may be optimized just before the speed threshold at which the flow condition of the algorithm is no longer true, or just before reaching the minimum speed if the flow condition is still true, alone or in conjunction with at least one of the aforementioned features.

SHORT DESCRIPTION THE DRAWINGS

1 is a block diagram of a simple pump system according to the present invention.

2 is a flowchart with the essential steps taken by an in 1 shown regulator according to the present invention.

three is a block diagram of in 1 shown regulator with at least one module configured to perform the in 2 shown essential steps.

4 FIG. 12 shows a flowchart for a process variable amount for constant flow control according to the present invention. FIG.

5 shows a flow chart for constant pressure control applications according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

1 shows the simple pump system according to the present invention generally with 2 is called and a controller 4 , a motor 6 and a pump 8th having. In operation and in accordance with the present invention, the controller determines 4 Flow reference data dependent on various pump and motor parameters, such as speed, torque, or power, or calibrated flow curves stored in an evaluation device (not shown) or an external flow reference unit, such as a flow meter (not shown), and uses the flow reference data to calculate the flow reference data pump 8th to regulate, as shown and described here.

2 shows an example of a flowchart, which is generally with 10 is called and the essential steps 10a and 10b of the algorithm for determining the pump flow through the regulator 4 can be realized according to the present invention. The determined flow value can also be used as input to a PID loop to control flow without an external flow meter or traditional gauges. The algorithm for determining the flow rate may be embedded in a frequency converter drive or in a programmable logic controller, as in FIG 1 in terms of the regulator 4 shown.

three : Regulator 4

three shows the main modules 4a . 4b and 4c of the regulator 4 , Many different types and types of regulators and control modules for controlling pumps are known in the art. One skilled in the art familiar with such controllers and control modules would be able to use control modules such as 4a and 4b implement and configure to perform functionality as described herein, that is, flow reference data as a function of various pump and motor parameters such as speed, torque, or power, or from calibrated flow curves stored in an evaluation device (not shown); or from an external flow reference unit such as a flow meter (not shown) and to use the flow reference data to the pump 8th like the in 1 and as described above, according to the present invention. The evaluation device and / or the flow meter may be in at least one of the modules 4a and 4b or in a combination thereof or form part of it.

By way of example, the functionality of the modules 4a and 4b by hardware, software, firmware, or a combination thereof, but it is not intended to limit the scope of the invention to any particular embodiment thereof. In a typical software implementation, such a module would be one or more microprocessor-based architectures including a microprocessor, random access memory (RAM), read only memory (ROM), input / output devices and controller, and data and address buses to its connection. One skilled in the art would be able to program such a microprocessor-based implementation without undue experimentation to achieve the functionality described herein. It is not intended to limit the scope of the invention to any particular implementation using any known or otherwise developed technique.

The regulator 4 has further control modules 4c known in the art, which are not part of the underlying invention and which are not described in detail herein. For example, the other rule modules 4c have such an evaluation device and / or such a flowmeter. Incidentally, such evaluation devices for storing flow curves and / or the flow meters for providing the external reference data are known in the art and will not be described in detail here. In addition, it is not intended to limit the scope of the invention to any particular type or manner thereof which is either now known or will be developed in the future. Embodiments can be considered in which the evaluation device and / or the flow meter are also in at least one of the control modules 4a and 4b are included or form part of it.

engine 6 and pump 8th

engine 6 and pump 8th are known in the art and will not be described in detail here. In addition, it is not intended to limit the scope of the invention to any particular type or manner thereof which is either now known or will be developed in the future. Furthermore, the scope of the invention should also include the application of the method according to the present invention in relation to the regulation of the operation of a centrifugal pump, a centrifugal mixer, a radial fan or a centrifugal compressor.

realization

It Today there are many processes with speed-resistant centrifugal pumps, the work with control valves in combination with a PID controller. In this arrangement, a control valve is throttled to use of feedback signals from an external process transmitter and a PID logic in a DCS (distributed control system), a PLC (programmable logic controller) or another loop control device to maintain the process setpoint. In many cases is the pump too big, and the cost of valve throttling can be seen from the point of view of energy consumption to be high. Will a speed-resistant pump continue operated away from their optimal flow, so also increase the acting on them radial and axial loads. The increased loads can be the Service life of the bearings and seals adversely affect and are the reliability of the system, resulting in unplanned maintenance of the device to lead can. Costs associated with unplanned maintenance include repair the facility, production stoppages and / or costs of disposal of environmental pollution.

It is therefore advantageous to operate a system in which the pump speed can be lowered so that valve throttling can be minimized and the pump as possible can work close to their optimal flow.

Lots Users want Although the benefits of lower operating costs and higher reliability of the system, but do not want changes at their control logic make still provide external input variables. This invention solves this through the use of a variable speed drive (VFD) and a control logic in an effort to control both the pump speed and also to optimize the position of the control valve without making any changes on the external control logic on the control valve are necessary. It also aims to to do this without the use of external input variables. The logic is as follows:

• – Maximale Pumpendrehzahl,
• – Minimale Pumpendrehzahl,
• – Motordrehmoment und
• – Motorleistung.

The VFD inputs to the logic include:

• - maximum pump speed,
• - minimum pump speed,
• - Motor torque and
• - engine power.

In one form, the logic operates with calculated flow data that 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 the In practice, however, this logic could use any drive parameter that has a direct or semi-direct relationship to pump flow. In addition, while the functionality is without any external process signal in the foreground in this logic, but also a direct measurement of the flow (on a flow meter) is possible. The logic can be embedded in either a frequency converter drive (VFD) or a programmable logic controller (PLC).

4 FIG. 12 shows a flowchart, indicated generally at 50, for a process variable amount for constant flow control; and FIG 5 applies to constant pressure control applications.

In the valve optimization process, there are three steps as follows:
Step 1 - The pump system starts and ramps up to the maximum speed. A check is made to ensure that the pump is not operating at zero flow - a potentially dangerous condition. If it operates at zero flow, the user can choose to have the unit malfunctioned (shut down) or to send a warning to the operator. When flow is established, after waiting one minute for the valve to respond to PID control, the process moves to the next step.

step 2 - The Valve optimization process starts as soon as the valve with PID control expires the one-minute delay reaches the setpoint at the maximum pump speed setting Has. The current flow value is stored as Q1. Subsequently, will the pump by a user adjustable speed step with a user adjustable Ramp slope gradually slowed down. Once a (user settable) delay has elapsed to the Control valve will give time to restore the setpoint in an exam the current flow compared with Q1. If the flow is unchanged (only more constant Flow) or has it increased or is it the same (only constant pressure), the lowering of the Speed iteratively continues until either the minimum pump speed is reached or the flow has dropped (only constant flow). is the flow dropped, so increased the logic slightly increases the speed by half a speed step until the current flow greater or greater is equal to the flow Q1 before the process goes to step 3. This is important in applications with high static heads. at Pressure control applications will check if the actual Flow in the range of 90 - 110% of the optimum flow, the flow value is less than Q1 is or the minimum speed is reached before the process starts Step 3 passes.

step 3 - The The purpose of step 3 is to ensure that the control valve does not work wide open is. If this condition "green light" is given, then pump speed and Valve position considered optimized. Takes a change motor torque or flow ≥ = + 5% over the optimized values longer than the response delay, thus it is concluded that an increase of the setpoint occurred is, and the valve optimization process is new at the maximum speed started. is the change motor torque or flow ≥ = -5% of the optimized torque or flow, it is concluded that the setpoint has been lowered, and the valve optimization process begins at Step 2. In certain applications, a user may set the setpoint increase, when the control valve is already almost open. This is not allowed to a simultaneous change the motor torque of> = 5% lead. For this Condition is a user selectable Feature exists with the for a valve state "far opened "is checked if a change of engine torque ≥ = + 2% (but less than 5%).

It should be noted that in the logic presented here though calculated flow values have been used, but instead the flow rate also used values of torque or power could become. The logic checks over the calculated flow value constantly to dry run, minimum flow (flow too low) or Outflow conditions (flow too high) and then warns either the user or turns off the unit and disturbed or puts the error automatically back and restarts the unit (if so configured) over the Pump protection logic shown in the provisional patent application at No. 60 / 780,529 (05GI002 / 911-2.22-1), filed on 8th of March 2006, and the corresponding regular patent application under the Reference 11 / 601,373 (05GI002 / 911-2.22-2), filed on 17 November 2006, both of which are incorporated by reference in their entirety become.

OTHER APPLICATIONS

existing Systems that operate with a control valve logic in which the Setpoint is achieved by valve throttling, usually at a fixed engine speed. These embedded in a VFD or a PLC Logic would allow optimization of pump speed and control valve position to reduce operating costs and increase the reliability of the system.

Scope of the invention

It it should be clear that, unless otherwise stated here, each) the characteristics, characteristics, alternatives or modifications that with respect to a particular embodiment described herein be, even with any other embodiment described here applied, used or included therein. Besides, they are the drawings in this document are not to scale.

Even though the invention with respect to exemplary embodiments thereof described and has been illustrated the aforementioned or various other additions and omissions thereto be made without the thought and scope of the present Deviate from the invention.

Claims (32)

A regulator, comprising: - at least one module that for determining flow reference data in dependence on different ones Pump and motor parameters such as speed, torque, or power, or from calibrated flow curves, in an evaluation device stored or from an external flow reference unit how a flow meter is configured, and - at least a module configured to use the flow reference data is to a centrifugal pump, a radial fan, a centrifugal mixer or a centrifugal compressor in a valve system with PID control too regulate. Controller according to claim 1, when, as soon as a valve with PID control its static Normal state, a calculated flow value is detected and with the current flow rate, which after the fall of the frequency (Speed) of the frequency converter drive is compared becomes. Controller according to claim 1, in which the valve position just before the speed threshold, at the flow condition of the algorithm is no longer true, is optimized. Controller according to claim 1, in which the valve position just before reaching the minimum Speed is optimized if the flow condition continues true is. Controller according to claim 1, in which the valve position is optimized in pressure control applications, if the current flow is within 90 - 110% of the optimal flow the pump is at the current speed. Controller according to claim 1, in which a final exam at a wide open Control valve performed by increasing the pump speed by a set amount and the current flow value with a stored flow value is compared; if the flow does not increase, then the valve position is optimized. Controller according to claim 1, in which case in the case that the regulator already optimized its State has reached and either the actual engine torque around 5% or more increases or the actual flow is longer than the delay time around 5% or more increases, the valve optimization process at maximum Speed is restarted. Controller according to claim 1, in which case in the case that the regulator already optimized its State has reached and either the actual engine torque around 5% or more drops or the actual Flow rate decreases by 5% or more, the valve optimization process restarts at the current operating point. Controller according to claim 1, which includes a user-selectable secondary check a wide open Valve performed will, whether a change of the actual Motor torque 2% or more, but less than 5% of the optimized Condition for the duration of the response delay is; this condition is true and the actual flow rate is greater than the optimized flow value after a change of the speed by one step, This restarts the optimization process at maximum speed. Controller according to claim 2, in which the valve position just before the speed threshold, at the flow condition of the algorithm is no longer true, is optimized. Controller according to claim 2, where the valve position is just before reaching the minimum speed is optimized if the flow condition is still true. Controller according to claim 2, which optimizes the valve position in pressure control applications if the current flow rate is within 90-110% of the optimum flow rate of the pump at the current speed. Controller according to claim 2, in which a final exam at a wide open Control valve performed by increasing the pump speed by a set amount and the current flow value with a stored flow value is compared; if the flow does not increase, then the valve position is optimized. Controller according to claim 2, in which case in the case that the regulator already optimized its State has reached and either the actual engine torque around 5% or more increases or the actual flow is longer than the delay time around 5% or more increases, the valve optimization process at maximum Speed is restarted. Controller according to claim 2, in which case in the case that the regulator already optimized its State has reached and either the actual engine torque around 5% or more drops or the actual Flow rate decreases by 5% or more, the valve optimization process restarts at the current operating point. Controller according to claim 2, which includes a user-selectable, secondary exam a wide open Valve performed will, whether a change of the actual Motor torque 2% or more, but less than 5% of the optimized Condition for the duration of the response delay is; this condition is true and the actual flow rate is greater than the optimized flow value after a change of the speed by one step, This restarts the optimization process at maximum speed. A method comprising: - Determination of flow reference data dependent on of different pump and motor parameters such as speed, torque or power or from calibrated flow curves stored in an evaluation device or from an external flow reference unit such as one Flow meter, and - Use the flow reference data to a centrifugal pump, a radial fan, a Centrifugal mixer or a centrifugal compressor in a valve system with PID control. Method according to claim 17, when, as soon as a valve with PID control its static normal state has reached a calculated flow value and with the current flow rate, which after the decrease of the frequency (speed) of the Frequency converter drive is compared. Method according to claim 17, in which the valve position just before the speed threshold, at the flow condition of the algorithm is no longer true, is optimized. Method according to claim 17, where the valve position is just before reaching the minimum speed is optimized if the flow condition is still true. Method according to claim 17, where the valve position is optimized for pressure control applications if the current flow rate is within 90-110% of the optimum flow rate of the pump at the current speed. Method according to claim 17, in which a final exam at a wide open control valve carried out is increased by the pump speed by a set amount and the current flow value with a stored flow value is compared; if the flow does not increase, then the valve position is optimized. Method according to claim 17, in which case in the case that the regulator is already in its optimized state has reached and either the actual engine torque around 5% or more increases or the actual flow is longer than the delay time increases by 5% or more, the valve optimization process at maximum Speed is restarted. Method according to claim 17, in which case in the case that the regulator is already in its optimized state has reached and either the actual engine torque around 5% or more drops or the actual Flow rate decreases by 5% or more, the valve optimization process restarts at the current operating point. Method according to claim 17, where a user-selectable, secondary check at a wide open Valve performed will, whether a change of the actual Motor torque 2% or more, but less than 5% of the optimized state for the Duration of the response delay is; is this condition is true and the actual flow rate is greater than the optimized flow value after a change of the speed by one step, This restarts the optimization process at maximum speed. Method according to claim 18, in which the valve position just before the speed threshold, at the flow condition of the algorithm is no longer true, is optimized. Method according to claim 18, in which the valve position just before reaching the minimum speed is optimized if the flow condition is still true. Method according to claim 18, where the valve position is optimized for pressure control applications if the current flow rate is within 90-110% of the optimum flow rate of the pump at the current speed. A method according to claim 18, wherein a final check is made on a wide open control valve by the pumps speed is increased by a set amount and the current flow value is compared with a stored flow value; if the flow does not increase, the valve position is optimized. Method according to claim 18, in which, in the event that the regulator is already in its optimized state has reached and either the actual engine torque around 5% or more increases or the actual flow is longer than the delay time increases by 5% or more, the valve optimization process at maximum Speed is restarted. Method according to claim 18, in which, in the event that the regulator is already in its optimized state has reached and either the actual engine torque around 5% or more drops or the actual Flow rate decreases by 5% or more, the valve optimization process restarts at the current operating point. Method according to claim 18, where a user-selectable, secondary check at a wide open Valve performed will, whether a change of the actual Motor torque 2% or more, but less than 5% of the optimized state for the Duration of the response delay is; is this condition is true and the actual flow rate is greater than the optimized flow value after a change of the speed by one step, This restarts the optimization process at maximum speed.