US Patent 11852356 Heating apparatus

The present technology relates to a tub for a humidifier comprising a container made of a first material, a heating element, and a lining made of a second, preferably biocompatible, material different from the first material, wherein the container comprises a base and a side wall defining a reservoir for a supply of liquid to be evaporated, the heating element is provided on the base of the container, and the lining covers the heating element and a substantial portion of the inner surface of the side wall of the container.