Patent ID: 11971380
Assignee: GRUNDFOS HOLDING A/S
Field: Measurement (Instruments)
Classification: CPC G  F | IPC F  G

Claim 12:
13. A pump device according to claim 1, wherein said evaluation unit is configured such that for detection of the concentration said cut-off frequency is detected and said capacitance of the liquid is calculated on basis of said cut-off frequency detected, wherein preferably the capacitance is determined by following equation:, C
   m
  
  =
  
   1
   
    2
    ⁢
    π
    ⁢
    
     R
     m
    
    ⁢
    
     f
     2
    
   
  
 

wherein Cm is the capacitance of the liquid, Rm is the resistance of the liquid and f2 is the upper cut-off frequency.