Abstract: A preheater suitable for a laboratory furnace provides improved furnace temperature uniformity and atmosphere control. The preheater comprises a rectangular chamber which is adapted to be placed in the bottom of the furnace chamber. The preheater includes a pair of longitudinal passageways on opposite sides of the preheater chamber. There is a plurality of perforations in the top wall at one end of the preheater and along each passageway for distributing preheated air or other gas into the furnace chamber. In a preferred embodiment, the preheater is made of stainless steel, and the preheater chamber contains stainless steel wool which aids in heat transfer.

Abstract: A self-sealing ceramic crucible and lid combination suitable for proximate analysis of coal or coke samples. The combination comprises a generally cylindrical crucible vessel having a substantially flat outside bottom surface one one end and being open on the other end, the wall of the vessel terminating at its open end in a rim which is finished circumferentially for sealing with the lid. The inside bottom surface is also preferably substantially flat. The lid member is generally cup-shaped and has a circular top wall and a depending circumferential skirt portion, the upper surface of the top wall being generally flat, the inside diameter of the top wall being slightly greater than the outside diameter of the crucible vessel, such that when the lid member is placed on the crucible vessel, the lower surface of the top wall which has a finished annular recess rests on the rim of the crucible, and the skirt of the lid member extends downwardy along the wall of the crucible and terminates in a circular edge.