Heat and moisture exchange devices
An HME has a housing ( 10 ) moulded in two parts ( 26 and 27 ) of a thick, thermally-insulative foamed plastics to form an enlarged central region ( 13 ) and opposite end walls ( 24 and 25 ). Separate patient and machine end couplings ( 11 and 12 ) are bonded to openings ( 37 and 47 ) in the end walls. The two housing parts ( 26 and 27 ) are bonded end to end about an HME element ( 14 ) formed by a strip of treated corrugated paper wound about a support sleeve ( 50 ).
1. A heat and moisture exchange (HME) device comprising a housing providing an inlet coupling, an outlet coupling and a transversely enlarged central region between the inlet and outlet couplings, the device including an HME element retained in the enlarged central region having opposite end faces spaced from respective inner opposing walls of the housing in the enlarged central region of the housing so that air can flow through the element across the entire surface of both faces, characterized in that a wall of the housing at least in the enlarged central region includes foamed plastic material having a thickness adapted to provide thermal insulation of the housing around the HME element.
2. An HME device according to claim 1 , characterised in that the foamed plastics material has a thermal conductivity of substantially 0.03 W/(m·K) or less.
3. An HME device according to claim 1 , characterised in that the ratio of the wall thickness of the enlarged central region to an external diameter of the foamed plastics material is substantially 1:8.
4. An HME device according to claim 1 , characterised in that the inlet and outlet are axially aligned with one another.
5. An HME device according to claim 1 , characterised in that the enlarged central region includes a cylindrical portion of circular section and two opposite end wall portions extending laterally to the inlet and outlet respectively.
6. An HME device according to claim 5 , characterised in that both the cylindrical portion and the wall portions are of the foamed plastics material through the major part of their thickness.
7. An HME device according to claim 5 , characterised in that at least an inner surface of the opposite end wall portions extend at an angle to the normal to an axis of the HME device.
8. An HME device according to claim 1 , characterised in that the inlet coupling and outlet coupling are components formed separate from the enlarged central region and attached with the enlarged central region.
9. An HME device according to claim 1 , characterised in that the HME element is a coil of corrugated paper.
10. An HME device according to claim 9 , characterised in that the coil of corrugated paper is wound about a hollow tubular sleeve.
11. An HME device according to claim 1 , characterised in that the housing is formed in two parts joined together at mating end surfaces in the enlarged central region.
12. An HME device according to claim 11 , characterised in that the mating end surfaces are inclined in opposite senses at an angle to the normal to an axis of the HME device.
13. An HME device according to claim 1 , characterised in that opposite end surfaces of the HME element each form a shallow, concave, conical shape.
14. A heat and moisture exchange (HME) device comprising: a housing providing an inlet coupling, an outlet coupling and a transversely enlarged central region between the inlet and outlet couplings, the device including an HME element retained in the enlarged central region having opposite end faces spaced from respective inner opposing walls in the enlarged central region of the housing so that air can flow through the element across the entire surface of both faces, a hollow tubular sleeve extending axially through the HME element between the opposite end faces of the HME element in alignment with the inlet and outlet couplings, wherein the housing has at least in the enlarged central region a wall including foamed plastic material having a thickness adapted to provide thermal insulation of the housing around the HME element.
15. An HME device according to claim 14 , further comprising a selectively openable valve in the tubular sleeve for reversing direction of air flow.
16. An HME device of claim 14 , wherein the housing comprises two parts bonded together at respective mating end surfaces about the HME element.
17. An HME device of claim 14 , wherein the foamed plastics material has a thermal conductivity of substantially 0.03 W/(m·K) or less.
18. A heat and moisture exchange (HME) device comprising: a housing providing an inlet coupling, an outlet coupling and a transversely enlarged central region between the inlet and outlet couplings, the device including an HME element retained in the enlarged central region having opposite end faces spaced from respective inner opposing walls in the enlarged central region of the housing so that air can flow through the element across the entire surface of both faces, a hollow tubular sleeve extending axially through the HME element between the opposite end faces of the HME element in alignment with the inlet and outlet couplings, wherein the housing has at least in the enlarged central region a wall including foamed plastic material having a thickness adapted to provide thermal insulation of the housing around the HME element, and wherein the tubular sleeve has respective flare ends, and wherein the inlet coupling and the outlet coupling have respective noses each extending into a corresponding one of the flare ends of the tubular sleeve to provide respective annular air flow passages around the outside of the respective noses.