Pulsed drop detector for intravenous systems
AssigneeRandom Corporation
InventorWilliam J. Dirr, Jr.
Life of this patent
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Abstract
A drop detector for intravenous systems in which an infrared emitter is pulsed at 10 kHz. The pulsed radiation passes through a drip chamber and then to a detector. The detector circuit determines the amplitude modulation of the 10 kHz. carrier frequency. This provides an indication of when the drop falling through the drip chamber has interrupted the light beam. An automatic gain control circuit maintains the output of the detector, on a long time constant basis, at a constant level to eliminate the vagaries of drip chambers with different optical characteristics and the like. When the AGC circuit lacks the ability to maintain the output of the detector circuitry at a constant level, a fault detector provides an alarm to indicate that the circuitry has exceeded its operational range.
Claims17
A drop detector comprising:
- (A) emitter means for providing an output of em. radiation of a generally specified wavelength;
- (B) pulsing means, coupled to said emitter means, for pulsing on and off at a particular frequency the output of said emitter means;
- (C) receiver means, located on a position to receive the em. radiation from said emitter means, for, upon the receipt of said em. radiation, providing a characteristic electrical signal;
- and
- (D) detector means, coupled to said receiver means, for detecting the amplitude modulation of the component of said electrical signal having said particular frequency.
A method of detecting drops through an area comprising:
- (A) passing through said area a beam of light with a specified wavelength and pulsed at a particular frequency;
- (B) receiving at least a portion of said beam after it has passed through said area;
- and
- (C) detecting the amplitude modulation of the component of said beam having said particular frequency.
Dependencies are inferred from the claim text.