US 4,727,886 AGranted

Inhalation detection apparatus

AssigneeGeneral Electric Company

InventorsJohn E. Conrardy, Bruce J. Fiorani, Robert H. Pedersen, Mark P. Steinert

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Abstract

Apparatus for detecting and indicating the commencement of inhalation by a patient under test includes a housing through which a gas flow due to the inhalation is directed. A light source and a light receptor positioned adjacent to transparent portions of the housing define a light path between them which transversely intersects the gas flow, the receptor being adapted to provide an output signal in response to incident light from the source. A movably positioned vane mounted inside the housing and normally biased to a position substantially clear of the light path, moves to a position progressively blocking the light path upon commencement of gas flow due to inhalation. Means responsive to a change in the receptor output signal resulting from blockage of the light path provides indication of the flow due to the inhalation commencement.

Claims10

Dependent claims

Apparatus for detecting and indicating the commencement of gas flow in a predetermined direction in a flow path, comprising:

a flow housing adapted to contain a gas flow in a predetermined direction;
a light source;
a light receptor adapted to provide an output signal in response to incident light from said light source;
said light source and said receptor defining a light path therebetween transverse to said gas flow;
a vane movably positioned in said gas flow and normally biased to a vane position substantially clear of said light path, said vane being responsive to gas flow in said predetermined direction to assume a vane position blocking at least a fraction of said light path;
an amplifier coupled to receive said light receptor output signal;
a peak detector coupled to the output of said amplifier, said peak detector including means for storing a signal having a magnitude slightly reduced from the magnitude of the amplifier output signal, and means for maintaining the level of the stored signal upon a sudden decrease in the amplitude of said amplifier output signal;
and
means responsive to the output signal from said peak detector and said amplifier output signal for providing an indication when said vane moves from one to the other of said vane positions.

6 more elements

Dependencies are inferred from the claim text.