Flow path fault detection method for a respiratory assistance apparatus

Patent metadata

Field	Value
Publication number	US-12420038-B2
Application number	US-202318178005-A
Country	US
Kind code	B2
Filing date	Mar 3, 2023
Priority date	May 23, 2012
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A respiratory assistance apparatus is configured to provide a heated and humidified glow of gases and has a control system that is configured to detect a fault in the flow path. A flow path is provided for a gases stream through the apparatus from a gas inlet through a blower unit and humidification unit to a gases outlet. A flow rate sensor is provided in the flow path and is configured to sense the flow rate and generate an flow rate signal and/or a motor speed sensor is provided that is configured to sense the motor speed of the blower unit and generate an indicative motor speed signal.

First claim

The invention claimed is:

1. A method for detecting a fault in a 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 that a motor speed falls below a stored first threshold at the first set flow rate;
increasing the flow rate to a higher second set flow rate when the motor speed falls below the first threshold;
determining the motor speed of the blower unit required to generate the second set flow rate in the flow path; and
detecting that the motor speed falls below a stored second threshold at the second set flow rate and generating a fault detection signal when the motor speed at the second set flow rate falls below the stored second threshold.

2. The method according to claim 1 wherein the first and second thresholds are discrete stored values.

3. The method according to claim 1 wherein the first set flow rate is within a first predetermined flow rate range and the second set flow rate is within a predetermined second flow rate range, the first predetermined flow rate range being different from and not overlapping with the second flow rate range.

4. The method according to claim 3 wherein the first set flow rate range comprises flow rates below 25 L/min and wherein the second set flow rate range is at or above 25 L/min.

5. The method according to claim 1 wherein the first set flow rate is a current operating flow of the respiratory assistance apparatus.

6. The method according to claim 1 wherein the method further comprises changing a current set flow rate of the respiratory assistance apparatus to the first set flow rate prior to determining the motor speed required to generate the first set flow rate.

Assignees

• Fisher & Paykel Healthcare Ltd

Inventors

• O'Donnell Kevin Peter
• Han John
• Hsu Jack Che-Wei
• Frame Samuel Robertson
• Dover Grant Martin

Classifications

• A61M2205/52

  with memories providing a history of measured variating parameters of apparatus or patient · CPC title

• A61M2205/3368

  Temperature · CPC title

• A61M2205/3334

  Measuring or controlling the flow rate · CPC title

• A61M2016/003

  with a flowmeter · CPC title

• A61M2205/707

  Testing of filters for clogging · CPC title