Wire heated tube with temperature control system for humidifier for respiratory apparatus
AssigneeResMed Limited
InventorsAdrian Ashley Vos, Ronald James Huby, Zhuo Ran Tang
Life of this patent
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Abstract
A PAP system for delivering breathable gas to a patient includes a flow generator to generate a supply of breathable gas to be delivered to the patient; a humidifier including a heating plate to vaporize water and deliver water vapor to humidify the supply of breathable gas; a heated tube configured to heat and deliver the humidified supply of breathable gas to the patient; a power supply configured to supply power to the heating plate and the heated tube; and a controller configured to control the power supply to prevent overheating of the heating plate and the heated tube.
Claims25
A sensing circuit for a heated conduit for use in a respiratory apparatus, the sensing circuit comprising:
- a sensing wire coupled to a heating circuit for the heated conduit;
- a temperature sensor coupled to the sensing wire and configured to measure the temperature of the heated conduit;
- a sensing resistor coupled to the sensing wire and configured to provide an output to indicate the temperature measured by the temperature sensor;
- and
- a bias generator circuit configured to provide a reference voltage to the sensing resistor to allow determination of the output as a function of a voltage drop across the sensing resistor during both heating on and heating off cycles of the heating circuit,
- wherein the bias generator includes a track and hold circuit configured to measure a voltage of the sensing wire and provide the measured voltage to the bias generator circuit, wherein the bias generator circuit is configured to adjust the reference voltage as a function of the measured voltage.
A control system for a heated conduit for use in a respiratory apparatus, the control system comprising:
- a power supply to provide power to the heated conduit;
- a heating control circuit configured to control heating to obtain a predetermined temperature;
- a sensing circuit configured to indicate the temperature of a sensor positioned in the heated conduit;
- and
- a bias generator circuit configured to provide a current to the sensor from a current source to allow for a voltage drop through the sensor that is recordable by the sensing circuit so that the temperature of the heated conduit is continuously monitored independent of whether the heating control circuit is on or off.
A control system for a heated conduit for use in a respiratory apparatus, the control system comprising:
- a power supply to provide power to the heated conduit;
- a heating control circuit configured to control heating to obtain a predetermined temperature;
- a sensing circuit including a sensing resistor configured to provide an output to indicate the temperature of a sensor positioned in the heated conduit;
- and
- a bias generator circuit configured to provide a reference voltage to the sensing resistor to allow determination of the temperature of the heated conduit as a function of a voltage drop across the sensing resistor during both heating on and heating off cycles,
- wherein a direction of the voltage drop across the sensing resistor changes when the heating circuit is on compared to when the heating circuit is off.
Dependencies are inferred from the claim text.