Heat recovery system

A heat recovery system for use in a multi-zone oven to recycle treatment air used to treat a grain based cereal product in a downstream oven zone to condition waste preheating air and create a preheating air for preheating the grain based cereal product in a preheating zone prior to entering the downstream oven zone, comprising:

• an oven having at least one oven zone for treating a grain based cereal product and including a zone inlet for the introduction of a treatment air having a treatment air temperature and treatment air dew point temperature for treating the grain based cereal product and a zone outlet for exhausting the waste treatment air following the treatment of the grain based cereal product;
• an oven duct assembly extending from said zone outlet to said zone inlet for exhausting the waste treatment air following the treatment of the grain based cereal product, wherein the waste treatment air is conditioned in said oven duct assembly for creating new treatment air to treat additional grain based cereal product;
• a preheating zone disposed upstream of said oven for preheating the grain based cereal product prior to entering the at least one oven zone and including a preheating inlet for the introduction of preheating air having a preheating air temperature and a preheating air dew point temperature for preheating the grain based cereal product and a preheating outlet for exhausting the waste preheating air following the preheating of the grain based cereal product;
• a preheating duct assembly extending from said preheating outlet to said preheating inlet for recirculating the waste preheating air following the preheating of the grain based cereal product, wherein the waste preheating air is conditioned in said preheating duct assembly for creating a new preheating air having the preheating air temperature and the preheating air dew point temperature to preheat additional grain based cereal product;
• and
• a transfer duct extending between said oven duct assembly and said preheating duct assembly for transferring a portion of waste treatment air from said oven duct assembly to said preheating duct assembly to condition the waste preheating air with the waste treatment air for creating the new preheating air to preheat additional grain based cereal product;
• wherein the preheating air preheats the grain based cereal product in the preheating zone to a product temperature being at least equal to the treatment air dew point temperature for eliminating surface condensation on the grain based cereal product during treatment in said oven zone.

A method of recycling waste treatment air used in a downstream oven zone of an oven for creating a preheating air to preheating a product in process prior to entering the downstream zone comprising the steps of:

• exhausting a waste treatment air through an oven duct assembly secured to a zone outlet in at least one oven zone following the treatment of a product in process;
• transferring a portion of the waste treatment air through a transfer duct extending between the oven duct assembly and a preheating zone;
• creating a preheating air having a preheating air temperature and a preheating air dew point temperature from the portion of the waste treatment air transferred to the preheating zone to preheat additional product in process;
• and
• introducing the preheating air into the preheating zone through a preheating inlet to preheat additional product in process.