Moisture detection in gases conveying medical conduits

1 . A humidifier system useable in a gases supply system, the humidifier system comprising:

a conduit comprising:

a first electrically conductive element; and

a second electrically conductive element;

a humidifier including an electrical connector, the electrical connector including a first electrical terminal or pad; and a second electrical terminal or pad, the first electrical terminal or pad and the second electrical terminal or pad are configured to electrically couple with the first electrically conductive element and the second electrically conductive element; and

a controller configured to monitor a signal using one or more of the first electrically conductive element and the second electrically conductive element to determine a value indicative of moisture in the conduit based at least in part on the signal;

wherein the signal is indicative of a capacitance, or a change in capacitance, between the first electrically conductive element and the second electrically conductive element.

2 . The humidifier system of claim 1 , the first electrically conductive element and the second electrically conductive element are separated by a distance configured to allow for a capacitive charge to be sensed between the first electrically conductive element and the second electrically conductive element.

3 . The humidifier system of claim 1 , further comprising a dielectric material located between the first electrically conductive element and the second electrically conductive element.

4 . The humidifier system of claim 3 , wherein the dielectric material is vapor or liquid permeable.

5 . The humidifier system of claim 4 , wherein the dielectric material is vapor permeable and allows evaporation of water to ambient air while inhibiting passage of liquid water and breathing gases to ambient air.

6 . The humidifier system of claim 1 , wherein the controller is configured to determine the value indicative of moisture based on a comparison of a measurement of the first electrically conductive element and/or the second electrically conductive element with a predetermined threshold.

7 . The humidifier system of claim 6 , wherein the value indicative of moisture comprises a time constant or a change in a time constant of a circuit comprising the first electrically conductive element or the second electrically conductive element in series with a reference resistor.

8 . The humidifier system of claim 1 , wherein the signal is indicative of a resonant frequency or a change in the resonant frequency of a circuit comprising the first electrically conductive element and/or the second electrically conductive element.

9 . The humidifier system of claim 8 , wherein the circuit is tuned to exhibit resonant behavior when sufficiently excited by the signal.

10 . The humidifier system of claim 1 , wherein the controller is configured to output an alarm if the value indicative of moisture falls below a first threshold value.

11 . The humidifier system of claim 1 , wherein the controller is configured to output an alarm if the value indicative of moisture falls below a first threshold value or exceeds a second threshold value.

12 . The humidifier system of claim 1 , wherein the controller is configured to automatically reduce humidification of breathing or insufflation gases in response to the value indicative of moisture in the conduit.

13 . The humidifier system of claim 1 , wherein the first electrically conductive element and the second electrically conductive element are spirally wound about at least a length of the conduit.

14 . The humidifier system of claim 1 , wherein the first electrically conductive element and the second electrically conductive element are spirally wound within, through, or around the conduit.

15 . The humidifier system of claim 1 , wherein the first electrically conductive element and the second electrically conductive element form part of walls of the conduit.

16 . The humidifier system of claim 1 , wherein the first electrically conductive element is a heater wire.

17 . The humidifier system of claim 1 , wherein the second electrically conductive element is a sensing wire.

18 . A cartridge for use with a humidifier in a respiratory or surgical humidification system, the cartridge comprising:

one or more sensors for sensing a property of a gases flow in a removable humidification chamber of the humidifier;

a first electrical connector configured to make a first electrical connection with a corresponding electrical connector of the humidifier;

a second electrical connector configured to make a second electrical connection with a corresponding electrical connector of an inspiratory conduit removably engageable with the cartridge, wherein the second electrical connector comprises at least a first electrical terminal or pad and a second electrical terminal or pad, the first electrical terminal or pad and the second electrical terminal or pad configured to make an electrical coupling respectively with a first electrically conductive element and a second electrically conductive element, and wherein the first electrically conductive element and the second electrically conductive element extend along at least a portion of a length of the inspiratory conduit; and

a controller communicatively coupled with the one or more sensors, the first electrically conductive element, and the second electrically conductive element;

wherein the controller is configured to monitor a signal using the first electrically conductive element and the second electrically conductive element, the signal indicative of a capacitance, or a change in capacitance, between the first electrically conductive element and the second electrically conductive element, and determine a value indicative of moisture in the inspiratory conduit based at least in part on the signal.

19 . The cartridge of claim 18 , wherein the cartridge is configured to be removably attached to the humidifier.

20 . A humidifier system useable in a gases supply system for supplying gases through a conduit comprising a first electrically conductive element and a second electrically conductive element, the humidifier system comprising:

a humidifier configured to connect to the conduit, the humidifier comprising:

an electrical connector comprising:

a first electrical terminal or pad; and

a second electrical terminal or pad;

wherein the first electrical terminal or pad and the second electrical terminal or pad are configured to electrically couple with the first electrically conductive element and the second electrically conductive element; and

a controller configured to monitor a signal using one or more of the first electrically conductive element and the second electrically conductive element to determine a value indicative of moisture in the conduit based at least in part on the signal;

wherein the signal is indicative of a capacitance, or a change in capacitance, between the first electrically conductive element and the second electrically conductive element.

21 . The humidifier system of claim 20 , wherein the controller is configured to determine the value indicative of moisture based on a comparison of a measurement of the first electrically conductive element and/or the second electrically conductive element with a predetermined threshold.

22 . The humidifier system of claim 21 , wherein the value indicative of moisture comprises a time constant or a change in a time constant of a circuit comprising the first electrically conductive element or the second electrically conductive element in series with a reference resistor.

23 . The humidifier system of claim 20 , wherein the signal is indicative of a resonant frequency or a change in the resonant frequency of a circuit comprising the first electrically conductive element and/or the second electrically conductive element.

24 . The humidifier system of claim 23 , wherein the circuit is tuned to exhibit resonant behavior when sufficiently excited by the signal.

25 . The humidifier system of claim 20 , wherein the controller is configured to output an alarm if the value indicative of moisture falls below a first threshold value or exceeds a second threshold value.