Method and apparatus for curing concrete products

Claim 1

Apparatus for curing concrete products which comprises: means forming an endless circular tunnel having a floor, walls, and a ceiling, said tunnel substantially airtight except for a product loading station at one portion thereof; means forming a track on the floor of said tunnel; a plurality of upstanding, interconnected racks movably mounted on said track, each rack including a solid upright wall panel extended transversely across said tunnel and including further vertically spaced shelves capable of cooperating with identical shelves of an adjacent rack to support pallets for carrying products to be cured; first sealing means secured about the periphery of each said rack; second sealing means secured at predetermined arcuately spaced locations on the inside of said tunnel and cooperable with said first sealing means to form a substantially airtight seal therewith, such that with a rack panel located momentarily at a said location a substantially complete airtight seal is provided completely across the said tunnel; means for moving said interconnected racks about said tunnel; said first and second sealing means coacting to form four separate arcuately arranged stations within said tunnel between said product loading station and a product unloading station; means connected to said tunnel means for introducing steam into a first of said stations and for maintaining said steam in a turbulent manner therein, said first station being maintained at a certain temperature; means connected to said tunnel means for introducing steam into a second of said stations adjacent said first station and for circulating said steam therein, said second station being maintained at a temperature higher than the temperature of said first station; means forming separate openings in said tunnel means for the entrance of air of ambient temperature into a third of said stations adjacent said second station, and for the egress of said air from said third station to the atmosphere; and means connected to said tunnel means for forcing air of ambient temperature into a fourth of said stations adjacent said third station, and said tunnel means having formed therein an opening at said fourth station for the egress of said forced air therefrom.