Pressure sensing

Abstract

A biological fluid device comprises a pressure sensor, which is arranged on the device. The pressure sensor comprises a compressible container, the compression of which is indicative of the pressure, and is capable of wireless communication.

1 - 28 . (canceled)  
     
     
         29 . A disposable sensor system, comprising: 
 a substrate;    a capacitor and an inductor fixed to said substrate to form a disposable pressure sensor thereof, wherein said inductor comprises an inductor surface, at least one electrode of a capacitor and a compressible wall, wherein when said compressible wall is exposed to a pressure, said compressible wall moves close to said inductor surface and/or said at least one capacitor electrode, thereby resulting in an increase in an inductance and/or a capacitance and a decrease in a resonant frequency associated with said capacitor and said inductor, wherein said increase and said decrease are detectable by external interrogation; and    interrogation electronics associated with said inductor and said capacitor, wherein said interrogation electronics externally detect said increase in said inductance and/or said capacitance and said decrease in said resonant frequency.    
     
     
         30 . The system of claim  1  further comprising a trimming mechanism for trimming said capacitor in order to calibrate data based on said decrease in said resonant frequency.  
     
     
         31 . The system of claim  1  further comprising a trimming mechanism for trimming said inductor in order to calibrate data based on said increase in said inductance.  
     
     
         32 . A device for transporting biological fluid in at least a part of an extracorporeal circuit, said at least part of the extracorporeal circuit being disposable and comprising: 
 at least one disposable sensor configured to be in fluid communication with the biological fluid, the at least one disposable sensor comprising: 
 a substrate,  
 a capacitor and an inductor fixed to said substrate to form a disposable pressure sensor thereof, wherein said inductor comprises an inductor surface, at least one electrode of a capacitor and a compressible wall, wherein when said compressible wall is exposed to a pressure, said compressible wall moves close to said inductor surface and/or said at least one capacitor electrode, thereby resulting in an increase in an inductance and/or a capacitance and a decrease in a resonant frequency associated with said capacitor and said inductor, wherein said increase and said decrease are detectable by external interrogation, and  
 interrogation electronics associated with said inductor and said capacitor,  
 wherein said interrogation electronics externally detect said increase in said inductance and/or said capacitance and said decrease in said resonant frequency.  
   
     
     
         33 . The disposable sensor of claim  1  further comprising a trimming mechanism for trimming said capacitor in order to calibrate data based on said decrease in said resonant frequency.  
     
     
         34 . The system of claim  1  further comprising a trimming mechanism for trimming said inductor in order to calibrate data based on said increase in said inductance.  
     
     
         35 . A disposable sensor method, comprising the steps of: 
 providing a substrate;    fixing a capacitor and an inductor fixed to said substrate to form a disposable pressure sensor thereof;    configuring said substrate to include an inductor surface, at least one capacitor electrode and a compressible wall, wherein when said compressible wall is exposed to a pressure, said compressible wall moves close to said inductor and/or a surface of said at least one capacitor electrode, thereby resulting in an increase in an inductance and/or a capacitance and a decrease in a resonant frequency associated with said capacitor and said inductor, wherein said increase and said decrease are detectable by external interrogation; and    associating interrogation electronics with said inductor and said capacitor, wherein said interrogation electronics externally detect said increase in said inductance and/or said capacitance and said decrease in said resonant frequency.    
     
     
         36 . The method of  claim 35  further comprising the step of calibrating data based on said decrease in said resonant frequency utilizing a trimming mechanism for said capacitor.  
     
     
         37 . The method of  claim 35  further comprising the step of calibrating data based on said increase in said inductance utilizing a trimming mechanism for said inductor.  
     
     
         38 . A disposable flow sensor comprising: 
 at least one pressure sensing device for detecting fluid pressure in a channel, wherein said at least one pressure sensing device comprises: 
 a compressible wall, and a capacitor electrically coupled to an inductor to form an LC tank circuit, said capacitor and/or inductor being mechanically coupled to said compressible wall such that a deflection of said diaphragm in response to fluid pressure applied thereto causes a change in the LC tank circuit inductance and/or capacitance and a change in the resonant frequency thereof, and wherein, when said at least one pressure sensing device is operatively coupled to said channel, said fluid pressure and said flow rate can be determined by detecting changes in said resonant frequency using interrogation.  
   
     
     
         39 . The sensor of  claim 38 , wherein said capacitor comprises a pair of spaced apart conductive plates, one of said plates being carried on or forming said compressible wall.  
     
     
         40 . The sensor of  claim 39 , wherein said inductor comprises a patch or layer of conductive or magnetic material carried on or forming said compressible wall, such that a deflection of said compressible wall causes a change in inductance of said inductor.  
     
     
         41 . The sensor of  claim 39  further comprising a substrate coupled to said compressible wall, said inductor and/or at one least one of said capacitor plates being carried on said substrate.  
     
     
         42 . The sensor of  claim 41  further comprising a calibration capacitor and/or calibration inductor carried on said substrate, said calibration capacitor and/or inductor being trimmable or adjustable for calibrating said pressure sensing device.  
     
     
         43 . A differential pressure flow sensor system comprising: 
 a disposable flow sensor comprising upstream and downstream pressure sensing devices for detecting a differential pressure between upstream and downstream locations of a flow channel;    wherein each of said pressure sensing devices comprises a compressible wall, a capacitor and an inductor electrically coupled to said capacitor so as to form an LC tank circuit, said capacitor and/or inductor being mechanically coupled to said compressible wall such that a deflection of said diaphragm in response to fluid pressure applied thereto causes a change in the inductance and/or capacitance of said LC tank circuit and a change in the resonant frequency thereof and, wherein, when said upstream and downstream pressure sensing devices are operatively coupled to said upstream and downstream channel locations, respectively, said differential pressure and said flow rate can be determined by detecting changes in said resonant frequency using interrogation.    
     
     
         44 . The system of  claim 43  further comprising external interrogation electronics for wirelessly detecting said change in resonant frequency of each of said pressure sensing devices.  
     
     
         45 . The system of  claim 43 , wherein said compressible wall of said pressure sensing devices are molded in a wall of said channel at upstream and downstream locations, respectively.  
     
     
         46 . The system of  claim 43  further comprising a substrate coupled to said compressible wall and, wherein said inductor and/or or at least one electrode plate of said capacitor is/are carried on said substrate.  
     
     
         47 . The system of  claim 46  further comprising a calibration capacitor and/or calibration inductor formed on said substrate, said calibration capacitor and/or inductor being trimmable or adjustable for calibrating said pressure sensing device.  
     
     
         48 . The system of  claim 43 , wherein said capacitor comprises a pair of spaced apart conductive plates, one of said plates being carried on or forming said compressible wall.  
     
     
         49 . The system of  claim 43 , wherein said inductor includes a patch or layer of conductive or magnetic material coupled to said compressible wall such that deflection of said diaphragm causes a change in inductance of said inductor.  
     
     
         50 . The system of  claim 43 , wherein said inductor includes a single patch or layer of conductive or magnetic material coupled to both compressible wall of said pressure sensing devices such that deflection of said compressible wall causes a change in inductance of said inductors of said pressure sensing devices.  
     
     
         51 . The system of  claim 43  further comprising a transceiver for wireless transmitting an electromagnetic interrogation signal to said pressure sensing devices and/or for receiving resulting resonant electromagnetic signals therefrom so as to detect said changes in resonant frequency.  
     
     
         52 . A method of manufacturing a flow sensor system for measuring the flow rate of fluid in a channel, said method comprising: 
 forming a pair of disposable pressure sensing devices for measuring the pressure differential in a flow channel; and    mechanically coupling said pressure sensing devices to said channel at upstream and downstream locations, respectively.    
     
     
         53 . The method of  claim 52 , wherein forming each disposable pressure sensing device comprises: forming a compressible wall; forming a capacitor and inductor; electrically coupling said capacitor to said inductor so as to form an LC circuit; and mechanically coupling said capacitor and/or inductor to said compressible wall such that a deflection of said compressible wall caused by pressure applied thereto causes a change in said capacitance and/or inductance of said LC circuit.  
     
     
         54 . The method of  claim 52  further comprising configuring external interrogation electronics for wireless detecting the resonant frequencies of said pressure sensing devices.  
     
     
         55 . The method of  claim 52  further comprising forming a trimmable capacitor and/or trimmable inductor on said pressure sensing devices for calibration thereof.