Liquid infusion apparatus
First Claim
1. An infusion apparatus having drive circuitry for an ultrasonic motor, comprising:
- 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;
a pair of air-core transformers, each having a secondary winding to connect to the ultrasonic motor, and having a pair of primary windings to conduct current therethrough in alternating relationship in response to output pulses from separate ones of pairs of the plurality of output terminals; and
a cam shaft coupled to the ultrasonic motor, the cam shaft further coupled to a plurality of pump elements, wherein rotation of the cam shaft by the ultrasonic motor manipulates the plurality of pump elements to adjust a pinch point along a tubing, thereby controlling an infusion fluid flow rate.
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Accused Products
Abstract
Liquid infusion apparatus includes non-magnetic materials in a pumping structure and ultrasonic drive motor therefor, and in a controller that supplies drive signals to the motor to facilitate convenient operation in intense magnetic fields without distorting the magnetic fields and without radiating objectionable radio-frequency interference. A non-MRI-compatible liquid infusion apparatus is temporarily replaced with MRI-compatible, non-magnetic liquid infusion apparatus without disconnecting a patient from an installed intravenous infusion set to continue infusing liquid within the MRI environment. The pumping apparatus operates on a segment of a liquid conduit that is mounted in tension between a linear peristaltic pump and platen, with associated safety interlocks to assure proper operation of infusing liquid into a patient compatibly with conditions in an MRI environment. Drive circuitry generates low-harmonic signals for operating the ultrasonic motor at variable speeds to compensate for flow rate discontinuities through the peristaltic pumping cycles.
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Citations
11 Claims
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1. An infusion apparatus having drive circuitry for an ultrasonic motor, comprising:
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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; a pair of air-core transformers, each having a secondary winding to connect to the ultrasonic motor, and having a pair of primary windings to conduct current therethrough in alternating relationship in response to output pulses from separate ones of pairs of the plurality of output terminals; and a cam shaft coupled to the ultrasonic motor, the cam shaft further coupled to a plurality of pump elements, wherein rotation of the cam shaft by the ultrasonic motor manipulates the plurality of pump elements to adjust a pinch point along a tubing, thereby controlling an infusion fluid flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification