Breathable gas apparatus with humidifier

A humidifier comprising:

• a base unit configured to attach to and detach from a flow generator, said base unit comprising:
• an engagement face adapted to face a corresponding engagement face of the flow generator;
• a plurality of tongues located on the engagement face that are adapted to move vertically and adapted to be resiliently urged downward to engage slots of the flow generator;
• an air flow passage in communication with a circular aperture in the engagement face, both the circular aperture and the air flow passage being configured to receive an air connector of the flow generator;
• a flexible face seal that defines a second aperture and is positioned at an end of the air flow passage, the flexible face seal having a peripheral portion that curves inwardly toward the second aperture;
• an electrical connector, for engagement with a mating electrical connector on the flow generator, the electrical connector of the humidifier adapted to provide electrical power to the humidifier from the flow generator;
• a circular pad positioned within a circular aperture in a lower surface of the base, the circular pad standing proud of the surrounding lower surface of the base and being resiliently biased upwardly through the circular aperture in the lower surface of the base;
• a heating element to heat the circular pad;
• a pivotable lid having a horizontal wall and a vertical wall extending downward from the horizontal wall;
• a pipe extending from an upper surface of the horizontal wall of the lid and opening into an internal region of the base unit;
• a lid seal attached to the lid, the lid seal having a sealing flange that extends downwardly from the lid and curves inwardly;
• and
• a biased lid catch for securing the lid in a closed position;
• and
• a tank adapted to attach to and detach from the base unit;
• the tank comprising:
• a cover;
• a base to receive water therein;
• a sealing gasket located between the cover and the base;
• an air inlet passage extending from a side wall of the tank;
• and
• an air outlet provided to a roof of the cover,
• wherein:
• the tank seats within the base unit so that a bottom of the tank is exposed to contact the circular pad when the tank is engaged with the base unit,
• one or more liquid filling heights are indicated by filling level graduations marked on a wall of the tank,
• the air inlet passage extends so that it opens in the interior of the tank at a point beyond, in the direction of air flow, a center of the air outlet,
• the air inlet passage and the air outlet are oriented so that gas flows through the air inlet passage in a direction perpendicular to a direction in which the gas flows through the air outlet,
• a vertical offset is provided between the air flow passage and the air inlet passage, with at least a portion of the air flow passage being lower than the air inlet passage in the normal orientation of the humidifier,
• the peripheral portion of the face seal that curves inwardly is adapted to abut a portion of the tank side wall surrounding an opening in the tank side wall proximate an inlet end of the tank air inlet passage to form a sealed air path from the air flow passage of the base unit to the air inlet passage of the tank when the tank is received in the base unit,
• the lid seal contacts the tank cover when the tank is received by the base unit and the lid is in the closed position so that the air outlet of the tank sealingly interfaces with the pipe,
• a first end of the pipe passes through the horizontal wall of the lid and has a lower end that projects beyond the horizontal wall of the lid into an interior of the base unit to terminate at a rim so that a passage of the pipe opens into the interior of the base unit,
• at least a portion of the lid seal surrounds the pipe, and
• at least a portion of the pipe is at an acute angle to the horizontal.