Tub for humidifier

1. A tub for a humidifier configured to humidify a flow of pressurized respiratory gas, the tub comprising:

a tub lid with an upper horizontal wall and an air outlet opening in the upper horizontal wall;

a tub base positioned below the tub lid, the tub base and the tub lid together forming a chamber configured to receive the flow of pressurized respiratory gas and contain a body of water, the tub base comprising a bottom surface with a central rim surrounding a depression in the bottom of the tub;

a plurality of heat stakes extending downward from the tub base and positioned around the depression in the bottom of the tub; and

a base plate attached to the bottom of the tub base, a perimeter of the base plate being greater than the perimeter of the depression in the bottom of the tub, the base plate being secured to the tub base by the plurality of heat stakes,

wherein the base plate comprises a plurality of coplanar tabs, each coplanar tab comprising an opening that receives a corresponding one of the plurality of heat stakes,

wherein each heat stake has a melted head portion that is larger than the opening in the corresponding one of the plurality of coplanar tabs, and

wherein a central region of the base plate is offset from the coplanar tabs.

2. The tub of claim 1 , wherein the tub comprises a side wall with an air inlet opening.

3. The tub of claim 2 , wherein the tub comprises an air inlet passage that extends laterally from the air inlet opening toward an interior of the tub.

4. The tub of claim 1 , wherein the melted head portions are in the shape of a dome.

5. The tub of claim 1 , wherein the heat stakes comprise plastic.

6. The tub of claim 1 , wherein the base plate is made of a heat-conducting metal.

7. The tub of claim 1 , wherein the plurality of heat stakes are equidistant from each other.

8. The tub of claim 1 , wherein the central region of the base plate is recessed with respect to the perimeter of the base plate.

9. The tub of claim 1 , wherein the central region of the base plate is recessed with respect to the coplanar tabs.

10. The tub of claim 1 , wherein the base plate is contained in a horizontal plane that is vertically offset from a horizontal plane in which the tabs of the base plate are contained.

11. The tub of claim 1 , wherein the tub comprises a side wall with an air inlet opening,

wherein the tub comprises an air inlet passage that extends laterally from the air inlet opening toward an interior of the tub,

wherein the melted head portions are in the shape of a dome,

wherein the heat stakes comprise plastic,

wherein the base plate is made of a heat-conducting metal,

wherein the plurality of heat stakes are equidistant from each other,

wherein the central region of the base plate is recessed with respect to the perimeter of the base plate, and

wherein the central region of the base plate is recessed with respect to the coplanar tabs.

12. A CPAP device configured to deliver a pressurized flow of respiratory gas to a patient's airways, the CPAP device comprising:

a flow generator configured to pressurize the flow of respiratory gas;

a humidifier cradle connected to the flow generator, the humidifier cradle comprising:

a cradle lid;

an outlet pipe extending from the cradle lid, the outlet pipe being configured to be connected to an air delivery tube; and

a cradle base with a heating element; and

the tub of claim 1 , the tub being configured to be removably inserted into the humidifier cradle and rest on the cradle base when inserted into the humidifier cradle.

13. The CPAP device of claim 12 , wherein the air outlet opening is configured to form an air flow path with the outlet pipe when the tub is received by the humidifier cradle and the cradle lid is in a closed position.

14. The CPAP device of claim 12 , wherein the base plate of the tub is configured to contact the heating element in the cradle base when the tub is received by the humidifier cradle.

15. The CPAP device of claim 12 , wherein the cradle lid is configured to sealingly engage the upper horizontal wall of the tub lid and is removable from the tub.

16. The CPAP device of claim 12 , wherein the tub comprises a side wall with an inlet opening configured to communicate with an air outlet opening of the flow generator when the tub is received by the humidifier cradle.

17. A CPAP device configured to deliver a pressurized flow of respiratory gas to a patient's airways, the CPAP device comprising:

a flow generator configured to pressurize the flow of respiratory gas;

a humidifier cradle connected to the flow generator, the humidifier cradle comprising:

a cradle lid that movable between an open position and a closed position;

an outlet pipe extending from the cradle lid, the outlet pipe being configured to be connected to an air delivery tube; and

a heating element; and

a water container configured to be removably inserted into the cradle, the water container comprising:

a water container lid with an air outlet opening that is configured to sealingly engage the cradle lid when the water container is received by the humidifier cradle and the cradle lid is in the closed position;

a water container base, the water container base comprising a bottom surface with an opening;

a plurality of heat stakes extending downward from the water container base and positioned on a rim of the opening in the water container base; and

a base plate that covers the opening in the bottom surface of the water container base and is secured to the water container base by the plurality of heat stakes, the base plate being configured to contact the heating element when the water container is received by the humidifier cradle,

wherein the base plate comprises a plurality of coplanar tabs, each coplanar tab comprising an opening that receives a corresponding one of the plurality of heat stakes,

wherein each heat stake has a melted head portion that is larger than the opening in the corresponding one of the plurality of coplanar tabs,

wherein a central region of the base plate is offset from the coplanar tabs,

wherein the cradle lid secures the water container in the cradle when the cradle lid is in the closed position, and

wherein the water container is allowed to be inserted into and removed from the cradle when the cradle lid is in the open position.

18. The CPAP device of claim 17 , wherein the water container comprises a side wall with an inlet opening configured to communicate with an air outlet opening of the flow generator when the water container is received by the humidifier cradle.

19. The CPAP device of claim 18 , wherein the water container comprises an air inlet passage that extends laterally from the inlet opening toward an interior of the water container.

20. The CPAP device of claim 17 , wherein the melted head portions are in the shape of a dome.

21. The CPAP device of claim 17 , wherein the heat stakes comprise plastic.

22. The CPAP device of claim 17 , wherein the base plate comprises a heat-conducting material.

23. The CPAP device of claim 17 , wherein the base plate is made of metal.

24. The CPAP device of claim 17 , wherein the water container further comprises a seal surrounding the opening in the water container base.

25. The CPAP device of claim 17 , wherein the water container further comprises a seal between the water container base and the base plate.

26. The CPAP device of claim 17 , wherein the water container further comprises a seal that surrounds the opening in the water container base.

27. The CPAP device of claim 17 , wherein the plurality of heat stakes are equidistant from each other.

28. The CPAP device of claim 17 , wherein the melted head portions of the heat stakes assist in holding the base plate against the water container base.

29. The CPAP device of claim 17 , wherein central region of the base plate is recessed with respect to the perimeter of the base plate.

30. The CPAP device of claim 17 , wherein the central region of the base plate is recessed with respect to the coplanar tabs with apertures.

31. The CPAP device of claim 17 , wherein the water container comprises a side wall with an inlet opening configured to communicate with an air outlet opening of the flow generator when the water container is received by the humidifier cradle,

wherein the water container comprises an air inlet passage that extends laterally from the inlet opening toward an interior of the water container,

wherein the melted head portions are in the shape of a dome,

wherein the heat stakes comprise plastic,

wherein the base plate comprises a heat-conducting material,

wherein the base plate is made of metal,

wherein the water container further comprises a seal surrounding the opening in the water container base,

wherein the water container further comprises a seal between the water container base and the base plate,

wherein the water container further comprises a seal that surrounds the opening in the water container base,

wherein the plurality of heat stakes are equidistant from each other,

wherein the melted head portions of the heat stakes assist in holding the base plate against the water container base,

wherein central region of the base plate is recessed with respect to the perimeter of the base plate,

wherein the central region of the base plate is recessed with respect to the coplanar tabs with apertures, and

wherein the base plate has raised edges.