Pump system

Abstract

The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (YS) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (YS).

What is claimed is: 
     
         1 . A method for operating a positive displacement pump, comprising:
 operating a positive displacement pump module;   controlling a drive motor rotational speed by a drive module including an electric drive motor and a frequency converter, the drive module being separately replaceable with respect to the positive displacement pump module; and   generating a first actual operating parameter (X) and a manipulated variable (YS) as a function of a reference input variable (W) by a controller having a regulator, the manipulated variable (YS) being receivable by the frequency converter, such that the manipulated variable (YS) is convertible by the frequency converter of the drive module through a corresponding energization of winding into the drive motor rotational speed;   wherein the drive module is replaceable separately from a control module.   
     
     
         2 . The method according to  claim 1 , wherein the manipulated variable (YS) is receivable by the frequency converter via a logic unit associated with the regulator. 
     
     
         3 . The method according to  claim 1 , further comprising supplying the reference input variable (W) by a control room for the controller. 
     
     
         4 . The method according to  claim 1 , wherein the controller is provided in the control module separate from the drive module. 
     
     
         5 . The method according to  claim 1 , further comprising determining, or signaling, or both, by the logic unit, a maintenance need of the positive displacement pump as a function of at least one of the first actual operating parameter (X), at least one additional actual operating parameter (XH, YH, YHH), and a parameter that is specific for the positive displacement pump assigned to the controller. 
     
     
         6 . The method according to  claim 5 , wherein the maintenance need is at least one of determinable and signalable by the logic unit a period of time before the positive displacement pump requires maintenance. 
     
     
         7 . The method according to  claim 2 , wherein the logic unit has first limit value specifying means configured to determine at least one first limit value as a function of the first actual operating parameter (X), and the at least one additional actual operating parameter (XH, YH, YHH);
 having first comparator means configured to determine the manipulated variable (YS) or a corrected manipulated variable (Y′S, Y″S), or to compare a comparative value determined according to a functional relationship from the manipulated variable (YS), or the corrected manipulated variable (Y′S, Y″S) with the at least one first limit value;   having first correction means configured to output a corrected manipulated variable (Y′S, Y″S) in response to the first comparator means detecting that the manipulated variable exceeds or falls below the at least one first limit value a certain amount, the corrected manipulated variable corresponding to the first limit value is determined by the first limit value specifying means; and   the logic unit having second limit value specifying means designed to determine at least one second limit value as a function of the first actual operating parameter (X) and at least one additional actual operating parameter (XH, YH, YHH);   having second comparator means designed to compare the manipulated variable (YS), or a corrected manipulated variable (Y′S, Y″S), or a comparative value determined according to a functional relationship from the manipulated variable (YS) or the corrected manipulated variable (Y′S, Y″S) with the at least one second limit value, and   having second correction means configured to output a corrected manipulated variable (Y′S, Y″) in response to the second comparator means detecting that the manipulated variable exceeds or falls below at least one second limit value a certain amount to output the corrected manipulated variable (Y′S, Y″S), corresponding to the second limit value, determined by the second limit value specifying means.   
     
     
         8 . The method according to  claim 7 , wherein the first actual operating parameter is a measured actual control variable (X) selected from the list consisting of an actual pressure, an actual pressure difference and an actual volume flow of the delivery fluid. 
     
     
         9 . The method according to  claim 7 , wherein the at least one additional actual operating parameter comprises at least one of:
 a measured actual control variable (X) selected from the list consisting of an actual pressure, an actual pressure difference and an actual volume flow of the delivery fluid;   a measured auxiliary manipulated variable (YH) calculated on the basis of the actual value or measured, the measured auxiliary manipulated variable (YH) comprising a rotational frequency setpoint value of the frequency converter or a torque setpoint value of the frequency converter;   a measured auxiliary control variable (XH) calculated on the basis of an actual value, the measured auxiliary control variable (XH) comprising a rotational speed of the positive displacement pump motor or a torque of the positive displacement pump motor; or   a measured temperature, in particular a delivery fluid temperature or a storage temperature of the positive displacement pump;   a measured vibration value;   a measured or calculated delivery fluid viscosity; and   a measured leakage rate.   
     
     
         10 . The method according to  claim 7 , wherein the logic unit comprises at least one comparative value determination means configured to determine on the basis of at least one of:
 a functional relationship from the manipulated variable (YS);   the corrected manipulated variable (Y′S, Y″S); and   the first and the at least one additional actual operating parameter (XH, YH, YHH) to determine the comparative value.   
     
     
         11 . The method according to  claim 10 , wherein the comparative value determination means are configured to at least one of:
 take into account the specific geometry parameters (GP) of a gap width or a spindle diameter which are specific to the positive displacement pump assigned to the control means and are stored in a memory within the context of the functional relationship; and   take into account in particular the shear behavior of the delivery fluid from a delivery fluid parameter (FP) stored in a memory.   
     
     
         12 . The method according to  claim 7 , wherein at least one of the first and second limit value specifying means are configured to:
 determine at least one of the first and second limit values as a function of the at least one specific geometry parameter (GP) a gap width or a spindle diameter assigned to the controller and stored in a memory; or   determine these values as a function of a delivery fluid parameter (FP) stored in a memory, wherein the delivery fluid parameter comprises the shear behavior of the delivery fluid; and   wherein at least one of the first and second correction means are configured to determine the corrected manipulated variable (Y′S, Y″S) as a function of at least one specific geometry parameter (GP), a gap width and a spindle diameter that is specific for the positive displacement pump assigned to the controller and stored in a memory and/or as a function of a delivery fluid parameter (FP) stored in a memory.   
     
     
         13 . The method according to  claim 7 , wherein at least one of the first and the second limit value specifying means are configured to determine at least one of the first and second limit values as a function of at least one of:
 a minimal or maximal shear rate in the positive displacement pump stored in a memory and specific for the positive displacement pump assigned to the controller;   the first or second correction means are designed to determine the corrected manipulated variable (Y′S, Y″S) as a function of at least one shear rate in the positive displacement pump which is stored in a memory and is specific for the positive displacement pump assigned to the controller; and   as a function of actual shear rate.   
     
     
         14 . The method according to  claim 7 , wherein at least one of the first and second comparator means are configured to compare at least one of:
 (1) the first actual operating parameter (X), (2) the at least one additional actual operating parameter (XH, YH, YHH), (3) a value calculated according to a functional relationship from the first actual operating parameter (X), (4) the at least one additional actual operating parameter (XH, YH, YHH), (5) a manipulated variable (YS) of the regulator, (6) a corrected manipulated variable, (7) a comparative value calculated on the basis of the manipulated variable (YS), and (8) the corrected manipulated variable (Y′S, Y″S),   with at least one limit value stored in a memory of the logic unit, and the first and/or second correction means are designed to output a corrected manipulated variable (Y′S, Y″S) when the first comparator means detects that the at least one defined limit value goes beyond the first limit value.   
     
     
         15 . The method according to  claim 7 , wherein in a nonvolatile memory at least one of different system parameter data records for different positive displacement pumps and different delivery fluid parameters (FP) are stored for manual selection. 
     
     
         16 . The method according to  claim 7 , wherein the controller includes a memory for storing at least one of the first actual operating parameters (X), the at least one additional operating parameter (XH, YH, YHH), the reference input variables (W), the comparative values, and the limit values, each with a time stamp. 
     
     
         17 . The method according to  claim 7 , wherein the process control room is configured for at least one of monitoring, controlling and regulating the positive displacement pump. 
     
     
         18 . The method according to  claim 7 , wherein the controller includes a signal-conducting connection to a sensor for receiving at least one of the first actual operating parameter (X) and at least one additional measured actual operating parameter (XH, YH, YHH) and wherein the controller have a signal-conducting connection for the frequency converter to receive at least one of the first actual operating parameter (X) and the at least one additional measured actual operating parameter (XH, YH, YHH);
 wherein the additional measure actual operating parameter (XH, YH, YHH) is selected from the list consisting of a positive displacement pump motor rotational speed, a rotational frequency setpoint value of the frequency converter, and a torque setpoint value of the frequency converter.   
     
     
         19 . A method for operating a positive displacement pump, comprising:
 operating a drive motor of a first pump module;   generating a rotational speed by a frequency converter based on a rotational speed output by a first control module for the operation of the drive motor;   determining a manipulated variable (YS) as a function of a reference input variable (W) being delivered to the first control module; and   controlling the drive motor by an actual operating parameter (X) and the determined manipulated variable (YS), the determined manipulated variable (YS) being delivered to the frequency converter, such that the manipulated variable (YS) is convertible by the frequency converter of the drive module through a corresponding energization of winding into the drive motor rotational speed;   wherein the drive module is replaceable separately from the control module.