Infusion pump with a capacitive displacement position sensor

Abstract

Various methods and devices are provided for an electrokinetic infusion pump. In one embodiment of the invention, the infusion pump includes an infusion pump module, which can be configured to dispense an insulin containing infusion liquid, and an electrokinetic engine. The infusion pump module includes a capacitive displacement position sensor configured for sensing a dispensing state of the infusion pump module. The infusion pump module can include an infusion module housing and the electrokinetic engine can include a moveable partition. The capacitive displacement sensor includes a first capacitive plate disposed on the moveable partition and a second capacitive plate disposed on the infusion module housing. The capacitive displacement sensor is configured for measuring capacitance between the first capacitive plate and the second capacitive plate and can send a feedback signal to a closed loop controller that is indicative of the capacitance between the first and second capacitive plates.

1 . An electrokinetic infusion pump comprising:
 an infusion pump module; and   an electrokinetic engine,   wherein the infusion pump module includes a capacitive displacement position sensor configured for sensing a dispensing state of the infusion pump module.   
   
   
       2 . The electrokinetic infusion pump of  claim 1 , wherein:
 the infusion pump module includes an infusion module housing;   the electrokinetic engine includes a moveable partition; and   the capacitive displacement sensor includes a first capacitive plate disposed on the moveable partition and a second capacitive plate disposed on the infusion module housing.   
   
   
       3 . The electrokinetic infusion pump of  claim 2 , wherein the first capacitive plate and the second capacitive plate each have a width of approximately 10 mm and a length of approximately 20 mm. 
   
   
       4 . The electrokinetic infusion pump of  claim 3 , wherein a gap between the first capacitive plate and the second capacitive plate has a dimension in the range of approximately 10-1000 micrometer. 
   
   
       5 . The electrokinetic infusion pump of  claim 2 , wherein the capacitive displacement sensor is configured for measuring capacitance between the first capacitive plate and the second capacitive plate. 
   
   
       6 . The electrokinetic infusion pump of  claim 1 , wherein the electrokinetic engine includes a moveable partition and the infusion pump includes an infusion housing, and wherein the capacitive displacement sensor is a dual capacitive displacement sensor that includes:
 a first capacitive plate and a second capacitive plate disposed on the moveable partition; and   a third capacitive plate and a fourth capacitive plate disposed on the infusion housing;   wherein the first capacitive plate, the second capacitive plate, the third capacitive plate and the fourth capacitive plate are in operative electrical contact and wherein an overlap between the second and fourth capacitive plate is constant and an overlap between the first capacitive plate and the third capacitive plate is dependent on a position of the moveable partition.   
   
   
       7 . The electrokinetic infusion pump of  claim 1 , wherein the capacitive displacement sensor is configured to send a feedback signal to a closed loop controller, the feedback signal indicative of the capacitance between the first and second capacitive plates. 
   
   
       8 . The electrokinetic infusion pump of  claim 1 , wherein the infusion pump is configured to dispense an insulin containing infusion liquid. 
   
   
       9 . An infusion pump system, comprising:
 an infusion pump that includes:
 a capacitive displacement position sensor; and 
 a closed loop controller, 
   wherein the infusion pump and closed loop controller are in operative communication and configured such that the closed loop controller can determine and control a dispensing state of the infusion pump based on a feedback signal received from the capacitive displacement position sensor.   
   
   
       10 . The system of  claim 9 , wherein the infusion pump is an electrokinetic pump. 
   
   
       11 . The system of  claim 10 , wherein the electrokinetic infusion pump further includes
 an infusion pump module; and   an electrokinetic engine,   and wherein the capacitive displacement sensor is configured for sensing a dispensing state of the infusion pump module.   
   
   
       12 . The system of  claim 11 , wherein:
 the infusion pump module includes an infusion module housing;   the electrokinetic engine includes a moveable partition; and   the capacitive displacement sensor includes a first capacitive plate disposed on the moveable partition and a second capacitive plate disposed on the infusion module housing.   
   
   
       13 . The system of  claim 12 , wherein the capacitive displacement sensor is configured for sensing a dispensing state by measuring capacitance between the first capacitive plate and the second capacitive plate. 
   
   
       14 . The system of  claim 13 , wherein the first capacitive plate and the second capacitive plate each have a width of approximately 10 mm and a length of approximately 20 mm. 
   
   
       15 . The system of  claim 14 , wherein a gap between the first capacitive plate and the second capacitive plate has a dimension in the range of approximately 10-1000 micrometer. 
   
   
       16 . The system of  claim 11 , wherein the electrokinetic engine includes a moveable partition and wherein the capacitive displacement sensor is a dual capacitive displacement sensor that includes:
 a first capacitive plate;   a second capacitive plate;   a third capacitive plate; and   a fourth capacitive plate,   and wherein the first capacitive plate, the second capacitive plate, the third capacitive plate and the fourth capacitive plate are in operative electrical contact and wherein an overlap between the second and fourth capacitive plate is constant and an overlap between the first capacitive plate and the third capacitive plate is dependent on a position of the moveable partition.   
   
   
       17 . The system of  claim 11 , wherein the electrokinetic engine includes an electrokinetic supply reservoir that is at least partially collapsible. 
   
   
       18 . The system of  claim 9 , wherein the capacitive displacement sensor is configured to send the feedback signal to the closed loop controller. 
   
   
       19 . The system of  claim 9 , wherein the infusion pump is configured to dispense an insulin-containing infusion liquid. 
   
   
       20 . A method for the closed loop control of an infusion pump, comprising:
 sensing a dispensing state of an infusion pump with a capacitive displacement position sensor;   signaling the sensed dispensing state of the infusion pump to a closed loop controller via a feedback signal;   determining, with the closed loop controller, the dispensing state of the infusion pump based feedback signal; and   controlling the dispensing state of the infusion pump with the closed loop controller by sending command signals from the closed loop controller to an engine driving the infusion pump.