Gas and solid particulate material heat exchanger

Apparatus for carrying out heat exchange between a gas and solid particulate material comprising a casing having an upper inlet for particulate material and a lower outlet for particulate material;

• a lower grate mounted in said casing extending from said upper inlet to said lower outlet for supporting a bed of particulate material for movement from the inlet to the outlet along the lower grate;
• means defining an upper grate mounted in said casing and spaced from said lower grate including a plurality of generally vertically oriented slats, each spaced from and positioned below a preceding slat in the direction from said inlet toward said outlet for defining the top of the bed of material while permitting the bed of material to expand;
• said casing including an inlet for gas on one side of the casing and an outlet for gas on the other side of the casing whereby gas flows from said inlet through said lower grate, the bed of material and through the upper grate to the outlet for gas for carrying out heat exchange between the gas and the solid particulate material, said slats being spaced apart from each other by a distance sufficient to hold the bed of material on the lower grate while allowing gas and fine material to pass therethrough;
• said casing being dimensioned so that the velocity of gas which has passed through the upper grate decreases by an amount to permit at least some of the fine material which passes through the upper grate to fall by gravity to the bottom of the casing.