An apparatus (1) for baking food products includes an elongated tunnel (3) defining an oven (5). A conveyor (13) conveys food through the tunnel. Gas supplied to the tunnel is combusted by burners (43, 45) and the heat generated by the combustion is imparted to an upper hearth (17) and a lower hearth...http://www.google.es/patents/US4884552?utm_source=gb-gplus-sharePatente US4884552 - Gas oven
