Removable and/or replaceable humidifier

1. A water distribution member for a humidifier apparatus, the water distribution member comprising:

an envelope formed by a first, substantially planar compartment wall and a second, substantially planar compartment wall joined together along a peripheral edge of the envelope

a water inlet opening into the envelope formed in a laterally-offset portion of said first substantially planar compartment wall, said laterally-offset portion extending outwardly of remaining portions of said peripheral edge; and

a heater element configured to be disposed below liquid water when in use, wherein the first substantially planar wall comprises at least in part a semi-permeable membrane, the semi-permeable membrane being configured to prevent liquid water from passing through while being structured to allow water vapour to pass through, and wherein the heater element is integrated with the second substantially planar compartment wall and wherein the second substantially planar wall is configured to conduct heat.

2. The water distribution member according to claim 1 , wherein the semi-permeable membrane comprises a finely perforated material.

3. The water distribution member according to claim 1 , wherein the semi-permeable membrane comprises a hydrophobic material.

4. The water distribution member according to claim 1 , wherein the water distribution member is adapted to be a removable and replaceable fitting to the humidifier apparatus.

5. The water distribution member according to claim 1 , further including a water filter in communication with the water inlet.

6. The water distribution member according to claim 1 , wherein the heater element comprises a heater plate.

7. The water distribution member according to claim 1 , wherein the envelope defines a thin water layer having a thickness of less than about 1 mm.

8. The water distribution member according to claim 1 , wherein the envelope defines a thin water layer having a thickness of less than about 5 mm.

9. The water distribution member according to claim 1 , wherein the envelope has a volume of less than about 150 ml.

10. The water distribution member according to claim 1 , wherein the envelope has a volume of less than about 100 ml.

11. The water distribution member according to claim 1 , wherein said second substantially planar compartment wall is comprised of a metal, metal plastic composite or metalized plastic film.

12. The water distribution member according to claim 1 wherein said first and second substantially planar compartment walls are joined by a bonding strip extending about peripheral edges thereof.

13. The water distribution member of claim 1 wherein a filter is located within said water inlet.

14. The water distribution member of claim 13 wherein said filter is supported by one or more ribs.

15. The water distribution member of claim 13 wherein said filter is comprised of a filter disc supported on an underlying support, and wherein the filter disc coincides with said water inlet in said first substantially planar compartment wall.

16. The water distribution member of claim 15 wherein said underlying support is provided with one or more ribs.

17. A water distribution member for a humidifier apparatus comprising an envelope formed by a first, substantially planar compartment wall and a second, substantially planar compartment wall joined together along a peripheral edge of the envelope, and a water inlet opening into the envelope formed in a laterally-offset portion of said first substantially planar compartment wall, said laterally-offset portion extending outwardly of remaining portions of said peripheral edge; wherein the first substantially planar wall comprises at least in part a semi-permeable membrane, the semi-permeable membrane being configured to prevent liquid water while being structured to allow water vapour to pass through, and wherein a heater element is incorporated in the second substantially planar compartment wall.

18. The water distribution member according to claim 17 , wherein the heater element comprises an induction receiving element.

19. Humidifier apparatus for a respiratory apparatus, comprising:

a housing;

one or more water supply distribution members removably fitted to the housing, wherein said one or more water supply distribution members comprises an envelope formed by a first upper, substantially planar compartment wall and a second lower, substantially planar compartment wall joined together along a peripheral edge of the envelope, a water inlet opening into the envelope formed in a laterally and outwardly-offset portion of said first substantially planar compartment wall, said laterally and outwardly-offset portion extending outwardly of remaining portions of said peripheral edge, wherein the first substantially planar compartment wall comprises a semi-permeable membrane being configured and arranged to prevent liquid from passing through and being configured to deliver water vapour to one or more gas flow paths defined by the one or more water supply distribution members and the housing; and

a heater apparatus in thermal communication with at least one of the water distribution members, the heater apparatus configured to be disposed below liquid water when in use, wherein the heater apparatus is integrated with the second substantially planar compartment wall.

20. The humidifier apparatus of claim 19 wherein the semi-permeable membrane comprises a hydrophobic material.

21. The humidifier apparatus of claim 19 wherein the heater apparatus comprises a filament or tape heater.

22. The humidifier apparatus of claim 19 wherein the heater apparatus comprises an induction heater.

23. A humidifier apparatus, comprising:

a base plate removably and replaceably attachable to a humidifier housing, the housing having a gas inlet, a gas outlet and a first water inlet;

a heater apparatus provided to the base plate; and

a water distribution member provided to the base plate, the water distribution member including first and second compartment walls joined together along a peripheral edge that define an envelope adapted to receive a supply of water via a second water inlet substantially aligned with said first water inlet, the first water inlet formed in a laterally-offset portion of the first compartment wall, said laterally-offset portion extending outwardly of remaining portions of said peripheral edge, the first compartment wall including a semi-permeable membrane adapted to prevent liquid from passing through and allow water vapour to pass therethrough and the second compartment wall including a thermally conductive wall in thermal communication with the heater apparatus, the heater apparatus configured to be disposed below liquid water when in use, the heater apparatus being integrated with the second compartment wall, and wherein said first water inlet in said housing increases in transverse cross section in an inward direction in order to distribute the water over a filter within the water distribution member.

24. The humidifier apparatus of claim 23 wherein the housing provides a gas flow path, and wherein a plate is located in said gas flow path, above said water distribution member, and configured and arranged to divide the gas flow path into two gas streams such that only one gas stream receives water vapour from the water distribution member and one or more devices are arranged to control the amount of gas flow into one or both gas streams.

25. The humidifier apparatus of claim 24 and further including one or more variable apertures placed between the water supply distribution member and the gas flow path.

26. The humidifier apparatus of claim 25 wherein the one or more variable apertures are structured to regulate the amount of water vapour transferred to the gas flow path.

27. The humidifier apparatus of claim 23 , wherein the semi-permeable membrane is hydrophobic.

28. A water distribution member for a humidifier apparatus, the water distribution member comprising:

an envelope formed by a first, substantially planar compartment wall and a second, substantially planar compartment wall joined together along a peripheral edge of the envelope;

a water inlet opening into the envelope formed in a laterally-offset portion of said first substantially planar compartment wall, said laterally-offset portion extending outwardly of remaining portions of said peripheral edge;

wherein the second substantially planar compartment wall includes a thermally conductive wall;

wherein said second substantially planar compartment wall is comprised of a metal, metal plastic composite or metalized plastic film and configured to prevent both liquid water and water vapour from passing therethrough; and

wherein the first substantially planar wall comprises at least in part a semi-permeable membrane, the semi-permeable membrane being configured to prevent liquid water from passing through while being structured to allow water vapour to pass through.

29. The water distribution member of claim 28 , wherein the semi-permeable membrane is hydrophobic.