Abstract: A sawdust and chip burner for use with an existing furnace for heating water or a forced air system. The burner overcomes a previously known deficiency in prior burners in overcoming burn-back, the latter meaning creeping of combustion back into the stored fuel. The burn-back hazard is overcome in the present invention by the provision of double-walling of the fuel hopper adjacent the exit thereof and the supplying of cooling air through the passage formed by the double walling. In addition to preventing burn-back, the cooling air exits at a higher temperature and the thus heated air may be used to augment the heat output from the burner.

Abstract: A bearing assembly for use in dusty and gritty environments having an enclosed roller or ball bearing on a short stub shaft and having a retainer ring for the outer race of the bearing, one side of the race being totally enclosed at the end remote from the stub shaft and two spaced apart sealing members disposed on the same side of the bearing as is the retaining ring, the sealing members being in sliding engagement with an interior bore in a rotating structure supported by the bearing and the exterior surface of the stub shaft.