Flow path sensing for flow therapy apparatus
A respiratory flow therapy apparatus including a sensor module can measure a flow rate of gases or gases concentration provided to a patient. The sensor module can be located after a blower and/or mixer. The sensor module can include at least an ultrasonic transmitter, a receiver, a temperature sensor, a pressure sensor, a humidity sensor and/or a flow rate sensor. The receivers can be immersed in the gases flow path. The receivers can cancel delays in the transmitters and improve accuracy of measurements of characteristics of the gases flow. The receivers can allow for detection of a fault condition in a blower motor of the apparatus.
1 . A respiratory assistance system or apparatus, the system or apparatus comprising:
a gases flow path configured to deliver a flow of gases to a patient;
a source of respiratory gases;
one or more acoustic receivers, the one or more acoustic receivers configured to detect an acoustic signal generated by the respiratory assistance system or apparatus; and
a controller configured to receive the detected acoustic signal and use the detected acoustic signal to determine a fault condition in the respiratory assistance system or apparatus;
wherein the controller is configured to determine the fault condition based on a relationship of amplitudes between different fault conditions, of the detected acoustic signal at a predetermined frequency or range of frequencies.
2 . The respiratory assistance system or apparatus of claim 1 , further comprising a blower configured to provide a high flow therapy to the patient.
3 . The respiratory assistance system or apparatus of claim 2 , wherein the blower and the one or more acoustic receivers are comprised within a removable blower and sensor module or a non-removable blower and sensor module.
4 . The respiratory assistance system or apparatus of claim 3 , wherein the removable or non-removable blower and sensor module comprises a sensing circuit board.
5 . The respiratory assistance system or apparatus of claim 4 , wherein the one or more acoustic receivers are located on the sensing circuit board.
6 . The respiratory assistance system or apparatus of claim 1 , wherein the one or more acoustic receivers are comprised within a removable sensor module.
7 . The respiratory assistance system or apparatus of claim 1 , wherein the respiratory assistance system or apparatus is further configured to generate one or more of audio or visual outputs in response to the fault condition being detected.
8 . The respiratory assistance system or apparatus of claim 1 , wherein the controller is further configured to determine the fault condition based on:
an amplitude of the detected acoustic signal at a predetermined frequency or range of frequencies;
a relationship of amplitudes of the detected acoustic signal between one or more different fault conditions at a predetermined frequency or range of frequencies; or
a threshold amplitude of the detected acoustic signal at a predetermined frequency or range of frequencies.
9 . The respiratory assistance system or apparatus of claim 8 , wherein the controller is configured to determine the fault condition based on the amplitude of the detected acoustic signal at the predetermined frequency or range of frequencies, wherein one or more fault conditions are distinguished based on a matching of the amplitude with a corresponding amplitude associated with the predetermined frequency or range of frequencies stored in a memory of the controller.
10 . The respiratory assistance system or apparatus of claim 8 , wherein the controller is configured to determine the fault condition based on the threshold amplitude, wherein the threshold amplitude is determined from a predetermined baseline amplitude or an amplitude at another frequency.
11 . The respiratory assistance system or apparatus of claim 1 , wherein the detected acoustic signal comprises at least in part a sound from a motor.
12 . The respiratory assistance system or apparatus of claim 1 , wherein the fault condition is related to or correlatable with a motor speed.
13 . The respiratory assistance system or apparatus of claim 1 , wherein the controller is configured to filter the detected acoustic signal to remove noise that is unrelated to motor noise.
14 . The respiratory assistance system or apparatus of claim 1 , wherein the controller is configured to analyze spectrally the detected acoustic signal to determine a frequency component indicative of an existence of the fault condition.
15 . The respiratory assistance system or apparatus of claim 1 , wherein the controller is configured to determine the fault condition based on a shape of the detected acoustic signal, wherein one or more fault conditions are distinguished based on a matching of the shape of the acoustic signal with a shape template corresponding to a particular fault condition stored in a memory of the controller.
16 . The respiratory assistance system or apparatus of claim 15 , wherein the shape of the acoustic signal is normalised for amplitude.
17 . The respiratory assistance system or apparatus of claim 1 , wherein the motor speed is varied during a fault condition detection operation and the controller is configured to determine the fault condition based on a corresponding varying of a portion of the detected acoustic signal caused by or relating to the fault condition.
18 . The respiratory assistance system or apparatus of claim 1 , wherein any sensors of the respiratory assistance system or apparatus are turned off during a fault condition detection operation.
19 . The respiratory assistance system or apparatus of claim 1 , wherein the one or more acoustic receivers comprise two acoustic receivers.
20 . The respiratory assistance system or apparatus of claim 1 , wherein the one or more acoustic receivers comprise one or more of condenser microphones, electret microphones, or MEMS microphones.
21 . The respiratory assistance system or apparatus of claim 1 , wherein the one or more acoustic receivers are located within the gases flow path.
22 . The respiratory assistance system or apparatus of claim 1 , wherein the controller is configured to estimate a temperature of the one or more acoustic receivers to be at the same temperature as a measured temperature of gases in the flow path.