Flow path fault detection method for a respiratory assistance apparatus

A method for detecting a fault in the flow path of a respiratory assistance apparatus, the flow path comprising a motor-driven blower unit that is configured to generate a flow of gases and which is connected to a humidification unit that is configured to heat and humidify the flow of gases, comprising:

• determining the motor speed of the blower unit required to generate a first set flow rate in the flow path;
• detecting if the motor speed falls below a stored first threshold at the first set flow rate;
• increasing the motor speed of the blower unit to a higher motor speed if the determined motor speed falls below the first threshold;
• sensing the flow rate in the flow path at the higher motor speed;
• and
• generating a fault detection signal if the sensed flow rate at the higher motor speed exceeds a stored second threshold.

A method for detecting a fault in the flow path of a respiratory assistance apparatus, the flow path comprising a motor-driven blower unit that is configured to generate a flow of gases and which is connected to a humidification unit that is configured to heat and humidify the flow of gases, comprising:

• sensing the flow rate in the flow path at a first motor speed of the blower unit;
• detecting if the sensed flow rate exceeds a stored first threshold at the first motor speed;
• increasing the flow rate to a higher set flow rate if the sensed flow rate exceeds the first threshold;
• determining the motor speed of the blower unit required to generate the higher set flow rate in the flow path;
• and
• generating a fault detection signal if the determined motor speed at the higher set flow rate falls below a stored second threshold.

A method for detecting a fault in the flow path of a respiratory assistance apparatus, the flow path comprising a motor-driven blower unit that is configured to generate a flow of gases and which is connected to a humidification unit that is configured to heat and humidify the flow of gases, comprising:

• sensing the flow rate in the flow path at a first motor speed of the blower unit;
• detecting if the sensed flow rate is below a stored first threshold at the first motor speed;
• increasing the motor speed of the blower unit to a higher second motor speed if the sensed flow rate is below the first threshold;
• re-sensing the flow rate in the flow path at the second motor speed;
• and
• generating a fault detection signal if the re-sensed flow rate at the second motor speed is below a stored second threshold.

A method for detecting a leak or blockage in the flow path of a respiratory assistance apparatus, the flow path comprising a motor-driven blower unit that is configured to generate a flow of gases and which is connected to a humidification unit that is configured to heat and humidify the flow of gases, comprising:

• sensing the flow rate in the flow path at a first motor speed of the blower unit;
• detecting if the sensed flow rate exceeds a stored first leak threshold at the first motor speed or is below a stored first blockage threshold at the first motor speed;
• increasing the motor speed of the blower unit to a higher second motor speed if the sensed flow rate exceeds the first leak threshold or is below the first blockage threshold;
• re-sensing the flow rate in the flow path at the second motor speed;
• and
• generating a fault detection signal if the re-sensed flow rate at the second motor speed exceeds a stored second leak threshold or is below a stored second blockage threshold.