Control of a pump device

Abstract

A method of controlling a pump device for discharging fluid, wherein the method comprises the steps of providing a heat portion adapted to be thermally coupled to the fluid to allow heat transfer there between when the fluid is at or above a certain level; monitoring a temperature parameter reflecting a temperature of the heat portion, the temperature parameter including a temperature value of the temperature of the heat portion; calculating a cooling rate value (CRV), the calculation including a comparison between at least two temperature values measured at different times; performing a pumping operation analysis including a comparison between a present cooling rate value (CRV) and a reference cooling rate value (ref), the reference cooling rate value representing a specific cooling rate of the heat portion; and initiating pumping operation to discharge the fluid if the cooling rate value is equal to or exceeds the reference cooling rate value.

1 . A method of controlling a pump device for discharging fluid, said method comprising the steps of:
 providing a heat portion adapted to be thermally coupled to said fluid to allow heat transfer there between when the fluid is at or above a certain level;   monitoring a temperature parameter reflecting a temperature of said heat portion, said temperature parameter including a temperature value of the temperature of said heat portion,   calculating a cooling rate value (CRV), said calculation including a comparison between at least two temperature values measured at different times   performing a pumping operation analysis including a comparison between a present cooling rate value (CRV) and a reference cooling rate value (ref), said reference cooling rate value representing a specific cooling rate of said heat portion; and   initiating pumping operation to discharge said fluid if said cooling rate value is equal to or exceeds said reference cooling rate value.   
     
     
         2 . The method according to  claim 1 , said method further comprising a step of heating said heat portion to a certain temperature or temperature difference above the temperature of said fluid. 
     
     
         3 . The method according to  claim 1 , said method further comprising a step of heating said heat portion if a difference between said temperature value and a reference temperature value (T low ) is equal to or below a reference difference value (k). 
     
     
         4 . The method according to  claim 2 , said method further comprising a step of repeating said step of heating said heat portion if pumping operation has not been initiated after a predetermined time interval (t 0 ). 
     
     
         5 . The method according to  claim 2 , wherein said step of heating said heat portion comprises electrically heating said heat portion. 
     
     
         6 . The method according to  claim 2 , wherein said step of heating said heat portion comprises heating said heat portion by a motor adapted to drive said pump device, said motor being thermally coupled to said heat portion. 
     
     
         7 . The method according to  claim 6 , wherein said heat portion is a portion of said motor. 
     
     
         8 . The method according to  claim 1 , said method further comprising a step of monitoring at least one motor load parameter reflecting the load of a motor being arranged for driving said pump device, said load parameter including an motor load value of the motor load of said motor. 
     
     
         9 . The method according to  claim 8 , said method further comprising the step of interrupting said pumping operation if said motor load value is below a reference motor load value. 
     
     
         10 . The method according to  claim 8 , wherein said motor is an electrical motor, and wherein said motor load value is based on the cosine of the phase difference (phi) between the voltage and the current over an electrical winding of said electric motor. 
     
     
         11 . The method according to  claim 6 , wherein said motor is an electrical motor, and wherein said heat portion is an electrical winding of said electric motor. 
     
     
         12 . The method according to  claim 2 , wherein said method further comprises the steps of:
 monitoring a fluid temperature parameter reflecting the temperature of said fluid, said fluid temperature parameter including a fluid temperature value of the temperature of said fluid; and   adapting at least one of the following parameters in relation to said fluid temperature value: said reference temperature value (T low ), said reference difference value (k), said reference cooling rate value (ref).   
     
     
         13 . The method according to  claim 1 , wherein said pump device is a submersible pump. 
     
     
         14 . The method according to  claim 1 , wherein said cooling rate value is a time derivate of said temperature of said heat portion. 
     
     
         15 . The method according to  claim 1 , wherein said cooling rate value is a heat transfer coefficient of said heat portion. 
     
     
         16 . The method according to  claim 1 , wherein said reference cooling rate value is a function of the heat portion temperature or a function of a normalized heat portion temperature. 
     
     
         17 . The method according to  claim 16 , wherein said function is an exponential function. 
     
     
         18 . The method according to  claim 1 , wherein said at least two temperature values are mean temperatures values. 
     
     
         19 . A control device for controlling a pump device for discharging fluid, said device comprising
 a heat portion adapted to be thermally coupled to said fluid when the fluid is at or above a certain level;   a first temperature sensor for monitoring a temperature of said heat portion, said first temperature sensor being adapted to provide a temperature sensor signal representing the temperature of the heat portion; and   a controller adapted to apply a control signal to a connectable pump device, said controller being further adapted to   calculate a cooling rate value (CRV) based on at least two temperature values measured at different times from the first temperature sensor signal at different times;   perform a pumping operation analysis including a comparison between a present cooling rate value (CRV) and a reference cooling rate value (ref), said reference cooling rate value representing a specific cooling rate of said heat portion; and to   apply a control signal to a connectable pump device to initiate pumping operation to discharge said fluid if said cooling rate value is equal to or exceeds said reference cooling rate value.   
     
     
         20 . The control device according to  claim 19 , wherein said controller is further adapted to apply a control signal to heating means adapted to heat said heat portion to a certain temperature or temperature difference above the temperature of said fluid resulting in a temperature difference between said heat portion and said fluid. 
     
     
         21 . The control device according to  claim 19 , wherein said controller is further adapted to apply a control signal to the heating means to heat said heat portion if a difference between said temperature value and a reference temperature value (T low ) is equal to or below a reference difference value (k). 
     
     
         22 . The control device according to  claim 20 , wherein said controller is further adapted to resume heating said heat portion if pumping operation has not been initiated after a predetermined time interval (t 0 ). 
     
     
         23 . The control device according to  claim 20 , wherein the heating means is adapted to electrically heat said heat portion. 
     
     
         24 . The control device according to  claim 20 , wherein the heating means comprises a motor adapted to be thermally coupled to said heat portion such that heat may be transferred to the heat portion during operation of the motor. 
     
     
         25 . The control device according to  claim 19 , wherein said heat portion is a portion of a motor connectable to the control device. 
     
     
         26 . The control device according to  claim 19 , wherein said control device comprises means for monitoring a motor load of a motor connectable to the control device, said motor being adapted to drive said pump device, and wherein said means for monitoring the motor load is adapted to provide a motor load signal representing said motor load. 
     
     
         27 . The control device according to  claim 26 , wherein said controller is further adapted to apply a control signal to said pump device to interrupt pumping operation if a motor load value from the motor load signal is below a reference motor load value. 
     
     
         28 . The control device according to  claim 26 , wherein said motor load value is based on the cosine of the phase difference (phi) between the voltage and the current over an electrical winding of said electric motor. 
     
     
         29 . The control device according to  claim 24 , wherein said motor is an electrical motor, and wherein said heat portion is at least a portion of an electrical winding of said electric motor. 
     
     
         30 . The control device according to  claim 20 , wherein said device further comprises a second temperature sensor for monitoring a temperature of said fluid, said second temperature sensor being adapted to provide a second temperature sensor signal representing said fluid temperature; and
 wherein said controller is further adapted to adapt at least one of the following parameters in relation to a fluid temperature value from the second temperature sensor signal:   said reference temperature value (T low ),   said reference difference value (k), and   said reference cooling rate value (ref).   
     
     
         31 . The control device according to  claim 19 , wherein said pump device is a submersible pump. 
     
     
         32 . The device according to  claim 19 , wherein said cooling rate value is a time derivate of said temperature of said heat portion. 
     
     
         33 . The device according to  claim 19 , wherein said cooling rate value is a heat transfer coefficient of said heat portion. 
     
     
         34 . The device according to  claim 19 , wherein said reference cooling rate value is a function of the heat portion temperature or a function of a normalized heat portion temperature. 
     
     
         35 . The device according to  claim 34 , wherein said function is an exponential function. 
     
     
         36 . The device according to  claim 19 , wherein said at least two temperature values are mean temperature values. 
     
     
         37 . A pump system comprising a pump device and a control device according to  claim 19 . 
     
     
         38 . The pump system according to  claim 37 , wherein said control device is integral with said pump device. 
     
     
         39 . The pump system according to  claim 38 , wherein said control device is removably connected with said pump device.