Abstract: A two stage material cooling apparatus for cooling hot particulate material such as cement clinker discharged from a furnace such as the rotary kiln. The first stage includes a direct heat exchanger such as a reciprocating grate type heat exchanger or an attached tube cooler and serves primarily as a heat recuperator. This cooler acts on the principle of direct heat exchange between cooling gas and the hot material whereby the material is cooled and the gas is heated and returned to the kiln as preheated secondary air for combustion. The second stage cooler is a shaft type cooler with gas permeable sides so that cooling gas passes through the material generally perpendicular to the flow of material. The gas which is supplied to the second cooler can come from recirculated cooling gas or from ambient. The gas discharged from the second cooler can be supplied directly to the gas inlet of the first cooler recirculated to its inlet after passing through an air to air heat exchanger.

Abstract: A spray nozzle which employs compressed air for atomizing the liquid to be sprayed and for projecting these droplets into the desired spray pattern. The nozzle includes a tubular member and a liquid supply conduit and nozzle head mounted within the tubular member. There is an annular passage through the nozzle with a converging portion and a portion diverging from the converging portion. Liquid and gas are supplied to the converging portion. The compressed gas is supplied in a manner to achieve swirling of both the gas and liquid within the converging portion. The compressed gas discharges the atomized liquid in a hollow conical spray pattern.