Abstract: A heater assembly includes a heating element assembly having a resistive heating element connected to a housing member. First and second guide members are oppositely and outwardly positioned with respect to the heating element assembly and extend away from the housing member. A patch plate includes an installation aperture and first and second wings extending away from the patch plate. The first and second guide members are positioned to individually slidingly engage with one of the first and second wings thereby defining a track system to permit the heating element assembly to be slidingly received through the installation aperture without contact between the resistive heating element and the patch plate.

Abstract: A resistive heating element for a resistance heater includes a first heating section and a second heating section. The first and second heating sections are configured to jointly generate a power output that is equal to that generated by a single reference resistive element under a same applied voltage. The single reference resistive element has a reference length, a reference mass, and a reference surface area. The first and second heating sections are configured to transfer an amount of heat at least equal to that transferred by the single reference resistive element. A total mass of the first heating section and the second heating section is less than a reference mass of the single reference resistive wire.

Abstract: Air conditioning apparatus is provided in which an air blower and an electric heater assembly are located in a common housing with the heater assembly projecting into the housing from a wall thereof in transverse relationship to the blower. This configuration eliminates the need for a dedicated space for the electric heater downstream of the blower housing, which reduces the size of the apparatus. The wall of the housing includes an opening through which the heater assembly is insertable into the housing. The heater assembly includes a mounting plate to close off the wall opening and to removably mount the heater assembly with the housing. The heater assembly preferably further includes an open coil electric heater, with a major dimension of the heater being oriented generally parallel to the direction of air flow in the blower housing.

Abstract: A method and apparatus for filtering a fluid through a particulate filter medium and for periodically scrubbing the particulate filter medium of accumulated contaminating material. During the filtration cycle, the particulate filter medium is retained with a filtration vessel by a bottom screen. During the scrubbing cycle, the particulate filter medium is retained within the filtration vessel by the bottom screen and a top screen. The combined surface area of the bottom screen and the top screen is substantially greater than the surface area of the bottom screen alone. During the scrubbing cycle, the particulate filter medium is fluidized with a scrubbing fluid and violently circulated to remove accumulated contaminating material from the filter medium, thereby suspending the contaminating material in the fluidized mixture.