Patent ID: 6976488

Claim:
A heat and moisture exchange (HME) unit comprising: a housing having a fibrous media therein that is designed to retain moisture and heat from exhaled air passing through said housing and to transfer the moisture and heat to inhaled air passing through said housing, wherein said housing includes a first HME housing portion and a second HME housing portion, the first HME housing portion being rotatably connected to the second HME housing portion; and an internal bypass in said housing to enable air to pass through said housing without passing through the fibrous media, wherein said bypass includes a first bypass housing secured to the first HME housing portion and a second bypass housing secured to the second HME housing portion and wherein the first bypass housing contains a first partial ramp and the second bypass housing contains a second partial ramp, such that as the first HME housing portion rotates relative to the second HME housing portion, the partial ramps are positioned with respect to each other to block and unblock said bypass.