Flow path fault detection method for a respiratory assistance apparatus

A respiratory assistance system which detects a blockage in a flow path, the respiratory assistance system comprising:

• a motor-driven blower unit which generates a gases stream at a configurable set flow rate into the flow path;
• a humidification unit comprising a removable humidification chamber which heats and humidifies the flow of gases in the flow path and which is fluidly connected or coupled to the motor-driven blower unit;
• and
• a controller which:
• controls a motor speed of the blower unit to deliver the gases stream at the set flow rate in normal operation;
• detects, in a first stage operating at a first motor speed or first set flow rate, a possible blockage based on comparing a sensed or determined motor speed or flow rate against a first blockage threshold that is based on a flow rate versus motor speed characteristic;
• increases the first motor speed or first set flow rate to a higher motor speed or higher set flow rate if an indicative blockage is detected in the first stage;
• detects, in a second stage operating at the higher motor speed or the higher set flow rate, a blockage based on comparing a sensed or determined motor speed or flow rate against a second blockage threshold that is based on a flow rate versus motor speed characteristic;
• and
• generates a blockage detection signal if a blockage is detected in the second stage.

A method for detecting a blockage in a flow path of a respiratory assistance apparatus, the flow path comprising a motor-driven blower unit that is configured to generate a gases stream at a configurable set flow rate and which is fluidly connected or coupled to a humidification unit comprising a removable humidification chamber that is configured to heat and humidify the flow of gases, comprising:

• controlling a motor speed of the blower unit to deliver the gases stream at the set flow rate in normal operation;
• detecting, in a first stage operating at a first motor speed or first set flow rate, a possible blockage based on comparing a sensed or determined motor speed or flow rate against a first blockage threshold that is based on a flow rate versus motor speed characteristic;
• increasing the first motor speed or first set flow rate to a higher motor speed or higher set flow rate if an indicative blockage is detected in the first stage;
• detecting, in a second stage operating at the higher motor speed or the higher set flow rate, a blockage based on comparing a sensed or determined motor speed or flow rate against a second blockage threshold that is based on a flow rate versus motor speed characteristic;
• and
• generating a blockage detection signal if a blockage is detected in the second stage.