Liquid infusion apparatus

Abstract

An apparatus and method are disclosed for controlling infusion of liquid into a patient using a peristaltic pump. The liquid infusion apparatus includes a liquid conduit having a proximal segment, a distal segment and an intermediate segment. The liquid infusion apparatus also includes a flow valve in fluid communication with the intermediate and distal segments. The flow valve includes a shuttle member slidably disposed within a housing about the distal segment, the shuttle member being configured for lateral movement relative to an elongated axis of the distal segment. The shuttle member is configured to operate in a first configuration to impede fluid flow through the liquid conduit and in a second configuration for which fluid flow through the liquid conduit is unimpeded. The shuttle member includes a resilient grasper for selectively engaging and disengaging a mating actuator resiliently received by the grasper.

1 . (canceled) 
     
     
         2 . A liquid infusion apparatus, comprising:
 an ultrasonic motor configured to provide displacement of a liquid from a liquid source through a liquid conduit;   an oscillator that generates an output at a frequency;   a circuit connected to receive the output from the oscillator to produce recurring output pulses at spaced intervals on a plurality of output terminals; and   a resistor-capacitor (RC) filter with an associated time constant, the RC filter configured to cause sweeping of the frequency of the output of the oscillator when a motor control signal indicates that the ultrasonic motor is to start running.   
     
     
         3 . The liquid infusion apparatus of  claim 2 , further comprising a feedback signal that provides an indication of the operation of the ultrasonic motor. 
     
     
         4 . The liquid infusion apparatus of  claim 3 , wherein the feedback signal operates in combination with the RC circuit to cause sweeping of the frequency of the output of the oscillator. 
     
     
         5 . The liquid infusion apparatus of  claim 3 , wherein the feedback signal is indicative of motor speed. 
     
     
         6 . The liquid infusion apparatus of  claim 2 , wherein the ultrasonic motor provides displacement of the liquid through the liquid conduit in a linear manner. 
     
     
         7 . The liquid infusion apparatus of  claim 2 , wherein the sweeping of the frequency of the output of the oscillator is from a higher frequency to a lower frequency. 
     
     
         8 . The liquid infusion apparatus of  claim 7 , wherein the higher frequency is useful for starting the motor from a standstill and the lower frequency is an appropriate frequency to establish a steady-state motor speed. 
     
     
         9 . The liquid infusion apparatus of  claim 2 , wherein the displacement of the liquid through the liquid conduit provides a constant fluid flow rate. 
     
     
         10 . The liquid infusion apparatus of  claim 2 , wherein the liquid infusion apparatus is compatible with an MRI environment. 
     
     
         11 . The liquid infusion apparatus of  claim 2 , further comprising a conductive housing that inhibits internally-generated RF noise signals from radiating out of the infusion apparatus. 
     
     
         12 . A liquid infusion apparatus, comprising:
 an ultrasonic motor configured to provide displacement of an IV fluid from a source of the IV fluid through a liquid conduit;   a voltage-controlled oscillator that generates an output at a frequency;   a drive circuit connected to receive the output from the voltage-controlled oscillator to produce recurring output pulses at spaced intervals on a plurality of output terminals; and   a resistor-capacitor (RC) filter with an associated time constant, the RC filter configured to facilitate sweeping of the frequency of the output of the voltage-controlled oscillator when a motor control signal indicates that the ultrasonic motor is to start running.   
     
     
         13 . The liquid infusion apparatus of  claim 12 , further comprising a feedback signal that provides an indication of the operation of the ultrasonic motor. 
     
     
         14 . The liquid infusion apparatus of  claim 13 , wherein the feedback signal operates in combination with the RC circuit to cause sweeping of the frequency of the output of the voltage-controlled oscillator. 
     
     
         15 . The liquid infusion apparatus of  claim 13 , wherein the feedback signal is indicative of motor speed. 
     
     
         16 . The liquid infusion apparatus of  claim 12 , wherein the ultrasonic motor provides displacement of the IV fluid through the liquid conduit in a linear manner. 
     
     
         17 . The liquid infusion apparatus of  claim 12 , wherein the sweeping of the frequency of the output of the voltage-controlled oscillator is from a higher frequency to a lower frequency. 
     
     
         18 . The liquid infusion apparatus of  claim 17 , wherein the higher frequency is useful for starting the motor from a standstill and the lower frequency is an appropriate frequency to establish a steady-state motor speed. 
     
     
         19 . The liquid infusion apparatus of  claim 12 , wherein the displacement of the liquid through the liquid conduit provides a constant fluid flow rate. 
     
     
         20 . The liquid infusion apparatus of  claim 12 , wherein the liquid infusion apparatus is compatible with an MRI environment. 
     
     
         21 . The liquid infusion apparatus of  claim 12 , further comprising a conductive housing that inhibits internally-generated RF noise signals from radiating out of the infusion apparatus.