Patent ID: 11957844
Assignee: FISHER & PAYKEL HEALTHCARE LIMITED
Field: Medical technology (Instruments)
Classification: CPC A  H | IPC A  H

Claim 0:
1. An apparatus for preparing a flow of gases including:
a heater for heating a reservoir,
a temperature sensor in thermal communication with the heater to read the temperature of the heater,
a controller adapted to apply power from a power supply to the heater, the controller including a control method comprising:
monitoring system conditions during use of the apparatus,
determining a possible absence of water in the reservoir from the monitored system conditions,
following a determination of a possible absence of water, apply an amount of power from the power supply to the heater, the amount of power being:
an increase in the supplied power,
a maximum power from the power supply to the heater,
a predetermined amount of power from the power supply to the heater; or
an amount of power to the heater that would elevate the heater temperature in the absence of water, to a temperature that exceeds any temperature that the heater temperature would reach with water present in the reservoir,

monitoring an output of the temperature sensor, and
reducing the power supplied from the power supply to the heater if the monitored temperature sensor output indicates an absence of water in the reservoir.