Heater plate for respiratory humidification systems

1. A respiratory humidification system configured to humidify a flow of respiratory gases supplied to a user, the system comprising:

a main housing configured to receive a removable humidification chamber;

a heating plate configured to be included in the main housing and positioned to contact the humidification chamber and transfer heat to the humidification chamber;

a heating element configured to provide heat to the heating plate;

a shroud configured to couple the heating element and the heating plate with the main housing; and

an intermediate layer including an adhesive configured to adhere the heating plate to the heating element and at least a portion of the shroud, the shroud comprising at least one relief channel located on a top surface of said portion of the shroud,

wherein the at least one relief channel is shaped to receive excess adhesive when the heating element is adhered to the heating plate.

2. The system of claim 1 , wherein the heating element comprises a substrate and a resistive track on the substrate.

3. The system of claim 1 , wherein the heating element comprises a substrate and a resistive track wound in turns on the substrate.

4. The system of claim 2 , wherein the resistive track is not disposed in a central region of the substrate.

5. The system of claim 2 , wherein the heating element further comprises a temperature sensor disposed on the substrate.

6. The system of claim 5 , wherein the temperature sensor is spaced from the resistive track.

7. The system of claim 6 , wherein a spacing between the temperature sensor and the resistive track is greater than spacing between portions of the resistive track.

8. The system of claim 7 , wherein the spacing between the temperature sensor and the resistive track is 1 cm to 20 cm, or 2 cm to 15 cm, or 5 cm to 10 cm, or 6 cm to 7 cm.

9. The system of claim 5 , wherein the temperature sensor comprises a plurality of temperature sensors.

10. The system of claim 5 , wherein the temperature sensor connects with conductors that terminate proximate an end of the substrate.

11. The system of claim 10 , further comprising a flexible PCB connected to the conductors.

12. The system of claim 11 , wherein the flexible PCB is connected to the conductors and the resistive track.

13. The system of claim 5 , wherein the temperature sensor is placed in a central region of the substrate so as to reduce a likelihood of the resistive track causing an incorrect measurement by the temperature sensor.

14. The system of claim 2 , wherein the resistive track is in an electrically in-series configuration.

15. The system of claim 2 , wherein the resistive track is a single resistive track.

16. The system of claim 15 , wherein two ends of the single resistive track terminate proximate the end of the substrate.

17. The system of claim 2 , wherein the resistive track comprises a thick film printed track.

18. The system of claim 2 , wherein the substrate is a part of a printed circuit board (PCB), a ceramic substrate, an aluminum oxide ceramic substrate, a fiberglass substrate, a mica substrate, a KAPTON™ substrate, a plastic substrate, or a silicone substrate.

19. The system of claim 1 , wherein the shroud comprises legs that attach the shroud to the main housing.

20. The system of claim 1 , further comprising potting that fills at least part of the shroud and at least partially encapsulates the heating element.

21. The system of claim 1 , wherein the at least one relief channel is recessed into the shroud, or comprises a curved shape, or comprises a groove, or is substantially around a perimeter of the shroud, or substantially surrounds the heating element, or is adjacent to the heating element, or comprises recessed corners that receive the heating element, or comprises four relief channels.

22. The system of claim 1 , wherein the shroud comprises a recessed region that receives the heating element, the recess comprising an uneven or textured surface.