Computer-implemented method for detecting and/or determining an anomaly in a centrifugal pump

Abstract

A computer-implemented method for detecting and/or determining an anomaly in a centrifugal pump includes the steps: in a normal state, accelerating and/or decelerating a rotor of the centrifugal pump for quantifying at least one term of a dynamic rotor model of the centrifugal pump, in a fault state differing from the normal state, accelerating and/or decelerating the rotor of the centrifugal pump for detecting at least one fault parameter, and solving an inverse problem of the dynamic rotor model for identifying the at least one fault parameter for detecting and/or determining the anomaly.

1 . A computer-implemented method for at least one of detecting and determining an anomaly in a centrifugal pump, comprising the steps:
 in a normal state, at least one of accelerating and decelerating a rotor of the centrifugal pump to quantify at least one term of a dynamic rotor model of the centrifugal pump,   in a fault state differing from the normal state, at least one of accelerating and decelerating the rotor of the centrifugal pump to detect at least one fault parameter, and   solving an inverse problem of the dynamic rotor model to identify the at least one fault parameter for detecting and/or determining the anomaly.   
     
     
         2 . The method according to  claim 1 , comprising the step:
 based on the determined anomaly, automatically or manually transferring the centrifugal pump from the fault state to the normal state.   
     
     
         3 . The method according to  claim 1 , wherein the quantifying of the dynamic rotor model, which is at least one of force-based and torque-based, involves at least one of detecting a braking torque of the normal state, detecting a friction term and detecting a hydraulic torque term time-dependent as a function of an angular velocity of the rotor. 
     
     
         4 . The method according to  claim 1 , wherein the quantifying the dynamic rotor model, which is a force-based dynamic rotor model, enables a total inertia of a rotating system of the centrifugal pump to be detected in the normal state. 
     
     
         5 . The method according to  claim 1 , wherein the quantifying the dynamic rotor model, which is a force-based dynamic rotor model, enables a total inertia of a rotating system of the centrifugal pump to be detected in the normal state including a liquid moved proportionally by the centrifugal pump. 
     
     
         6 . The method according to  claim 3 , wherein the quantifying is carried out taking into account at least one of a characteristic curve and a characteristic diagram, taking into account at least one of a system characteristic curve, a geodetic height difference, a gate valve, a valve, a bypass, a non-return flap, a position of the valve, a filling level of a pipeline and a length of pipeline. 
     
     
         7 . The method according to  claim 1 , wherein the dynamic rotor model comprises a braking torque of the normal state which is dependent on at least one of a rotational speed and angular velocity 
       
         
           
             
               
                 
                   M 
                   R 
                 
                 ( 
                 
                   
                     
                       φ 
                          
                     
                     ˙ 
                   
                   ⁢ 
                   
                     ( 
                     t 
                     ) 
                   
                 
                 ) 
               
               := 
               
                 
                   
                     ∑ 
                     
                       i 
                       = 
                       1 
                     
                     N 
                   
                      
                   
                     
                       k 
                       i 
                     
                     ⁢ 
                     
                       
                         
                           φ 
                           ˙ 
                         
                         
                             
                           
                             r 
                             i 
                           
                         
                       
                       ( 
                       t 
                       ) 
                     
                   
                 
                 + 
                 
                   
                     M 
                     T 
                   
                   ( 
                   
                     
                       
                         φ 
                            
                       
                       ˙ 
                     
                     ⁢ 
                     
                       ( 
                       t 
                       ) 
                     
                   
                   ) 
                 
                 + 
                 
                   
                     M 
                     I 
                   
                   ( 
                   
                     
                       φ 
                       ˙ 
                     
                     ⁢ 
                        
                     
                       ( 
                       t 
                       ) 
                     
                   
                   ) 
                 
               
             
           
         
         with
 k i  coefficients of the angular velocity of the rotor, 
 r i  exponents of the angular velocity of the rotor, 
 M T  torque function of a transfer from static to sliding friction of the rotor, and 
 M I  torque of an impeller of the centrifugal pump. 
 
       
     
     
         8 . The method according to  claim 7 , wherein the dynamic rotor model, according to the following equation, comprises in the normal state an inertia term and a braking torque on the left-hand side of the equation and a time-dependent motor torque on the right-hand side of the equation, 
       
         
           
             
               
                 
                   J 
                   ⁢ 
                   
                     φ 
                     ¨ 
                   
                   ⁢ 
                      
                   
                     ( 
                     t 
                     ) 
                   
                 
                 + 
                 
                   
                     M 
                     R 
                   
                   ( 
                   
                     
                       
                         φ 
                            
                       
                       ˙ 
                     
                     ⁢ 
                     
                       ( 
                       t 
                       ) 
                     
                   
                   ) 
                 
               
               = 
               
                 
                   M 
                   M 
                 
                 ( 
                 t 
                 ) 
               
             
           
         
         with
 J inertia moment. 
 
       
     
     
         9 . The method according to  claim 8 , wherein the inertia moment is the sum of various inertia effects of at least one of rotating fixed parts, liquid in the impeller, liquid in the pump housing and in parts of a pipeline system of the centrifugal pump. 
     
     
         10 . The method according to  claim 1 , wherein detecting the dynamic rotor model in the normal state comprises at least one of calculating and experimentally determining an inertia moment. 
     
     
         11 . The method according to  claim 1 , wherein solving the inverse problem comprises classifying at least one of the anomaly and the fault state. 
     
     
         12 . The method according to  claim 2 , wherein transferring the centrifugal pump from the fault state to the normal state is based on the classification of at least one of the anomaly and the fault state. 
     
     
         13 . The method according to  claim 1 , wherein the at least one fault parameter comprises at least one of a breakaway torque, a static friction, a constant torque, a Coulomb sliding friction, represents a coefficient of an angle of rotation, represents a stiffness, a coefficient of an angular velocity, a damping, a coefficient of an angular acceleration, and an inertia. 
     
     
         14 . The method according to claim  14 , wherein the at least one fault parameter comprises at least one of a breakaway torque and a static frictional torque of at least one of the fault state and the acceleration of the rotor for detecting the fault parameter comprises an increase of a motor torque from zero until a first movement of the rotor, wherein a static frictional torque of the anomaly results from a motor torque present at the first movement minus a breakaway torque of the normal state. 
     
     
         15 . The method according to  claim 14 , comprising the step:
 after the initial movement of the rotor, increasing an angular velocity of the rotor to a constant value by at least one of controlling and adjusting the motor torque, and   after reaching the constant angular velocity, at least one of measuring and calculating an angle of rotation of the rotor by means of an integration method, wherein the angle-related at least one fault parameter is obtained as a derivative of the motor torque according to the angle of rotation.   
     
     
         16 . The method according to  claim 14 , comprising the step:
 determining K coefficients for angular velocities with different exponents as well as the at least one fault parameter, as velocity-independent Coulomb friction, corresponding to a coefficient of an angular velocity with the exponent zero,   by solving a linear equation system with K+1 linearly independent equations, where the equations can be associated with pairwise different constant angular velocities in a range between low and high rotational speeds of the rotor.   
     
     
         17 . The method according to  claim 1 , comprising the step:
 calculating an additional inertia moment during positive or negative acceleration in a predetermined angular velocity range.   
     
     
         18 . The method according to  claim 14 , comprising the step:
 determining, based on the at least one of a breakaway torque and the static frictional torque of at least one of the fault state, the fault state comprising no blockage, blockage between a rotating and a fixed part of the centrifugal pump, blockage leading to the standstill of an impeller of the centrifugal pump or blockage inside an impeller channel of the centrifugal pump.