Abstract: This bio-fuel furnace includes a combustion unit and separate fuel feed unit mounted atop the combustion unit. The combustion unit includes a cylindrical burn pot, a preheat module, an expansion bowl and a primary heat exchanger supported by an inner frame and enclosed by an outer casing. The preheat module is a rectangular box having an internal spiral baffle. The burn pot is seated within a central opening in the preheat module. The expansion bowl is seated atop the preheat module and the primary heat exchanger is mounted above the expansion bowl. An inlet fan blows inlet air through the preheat module and into the burn pot and an outlet fan draws exhaust air around the primary heat exchanger from the combustion unit. The fuel feed unit has an internal storage bin and a rotating scoop arm deposits the bio fuel into the combustion unit.

Abstract: A level sensing unit, designed to be incorporated in a carpenter's level, is relatively insensitive to the expansion and contraction of the buoyant fluid, independent of the specific gravity of the fluid, and virtually free of oscillations accompanying a change in liquid orientation. The device can be constructed inexpensively of commonly available materials. The device has a float with an electrically conducting plate bisecting the float between its ends and is pivotally mounted on pins protruding from walls of a sealed housing. Adjacent to the opposing surfaces of the plate are two electrically conducting strips. At level neither strip contacts the nearest surface of the plate, but when the unit is not at level one or the other strip makes physical and electrical contact.

Abstract: A level sensing unit, designed to be incorporated in a carpenter's level, is relatively insensitive to the expansion and contraction of the buoyant fluid, independent of the specific gravity of the fluid, and virtually free of oscillations accompanying a change in liquid orientation. The device can be constructed inexpensively of commonly available materials. The device has a cylindrical float mounted on a centrally positioned axle with a plate extending above the float surfaces and placed normal to the axle. The axle extends between the walls of a sealed housing, and adjacent to the edge of the plate are two electrically conducting strips. At level neither strip contacts the edge of the plate, but when the unit is not at level one or the other strip makes physical and electrical contact.

Abstract: There is described a level sensing unit which is simple to operate, rugged in construction, sensitive to angular deviations of about 4 minutes 30 seconds, relatively inexpensive to construct, and very reliable. The unit is a sealed housing containing two communicating channels as fluid reservoirs opening into a compartment with an axle mounted between the channels and a float for each channel pivotally connected to the axle. Each float has an electrically conductive extension in electrical contact with the axle and directed toward a strip of similarly conductive material mounted within the housing. When the channels are filled with a nonconductive reactive fluid the extensions are in electrical contact with the strips when the floats are in a level condition, and the extensions become electrically disengaged through a buoyant force exerted on one float when the device is rotated so as to deviate from level.