Kiln

Claim 1

A kiln for baking items progressively moving along the kiln, comprising a hollow elongated housing having an inlet and an outlet to receive and discharge the items to be treated, said housing including a preheating section, a baking section, a cooling section and a section for nature cooling, all successively located in said housing; means for introducing a cooling medium into said cooling section including a first blower and first regulating means connected to said first blower to control the amount of the cooling medium entering said cooling section, said introducing means being associated to a space in the cooling section immediately following said baking section to provide a substantial drop of the temperature of said items for accelerating the cooling process; means for withdrawing said medium as said medium is heated in heat exchange relationship with said items including first conduit means for receiving said withdrawn medium, second conduit means for receiving said withdrawn medium and ambient air from a supply source to be mixed with said medium to provide enriched combustion air, a second blower positioned between said first conduit means and said second conduit means and second regulating means connected to said second blower, said second regulating means being operatively connected to said first means to control the amount of medium to be withdrawn from said cooling section; means for connecting said second conduit means to said baking section for supplying the latter with enriched combustion air; third conduit means for receiving the gases from said section of natural cooling which gases are being heated in heat exchange relationship with said items to be cooled; connecting conduit means located between said withdrawing means and said third conduit means; discharging means connected to said baking section to withdraw hot gases therefrom, said discharging means being associated with said third conduit means; and means for mixing said hot gases from said discharging means and heated gases from said third conduit means; and means for drawing the mixture to said pre-heating section; separating means to separate said sections one from another for preventing undersired mutual influence in different treating regimes and said separating means include sets of baffles mounted on an inner wall of said housing and located adjacent one to another so as to thermally separate each of two successive sections.