Induced draft heat exchanger with serpentine baffles

Abstract

A cooking system including a vessel having a first end, a second end, and a pair of opposing side walls and containing a cooking medium. A first heat exchanger tube has an outer wall and extends through the vessel from the first end to the second end. The first heat exchanger tube has a first inlet in the first end and a first outlet in the second end. The first heat exchanger tube also includes a combustion gas director tube, a first upper passage, and a first lower passage, wherein the director tube is joined to the first inlet and directs combustion gas into the upper passage and the upper passage is in communication with the lower passage. An upper transition baffle is placed in the first upper passage to smoothly direct combustion gases from the director tube into the first upper passage. Similarly, a communication passage is formed between the first upper passage and the first lower passage, and a lower transition baffle is placed in the communication passage to smoothly direct combustion gases from the first upper passage to the first lower passage. A burner introduces combustion gases into the upper passage through the first inlet, and air enter the upper passage through a gap between the burner and the first inlet to ensure the laminar flow of the combustion gases. A second heat exchanger tube is in contact with one of the opposing side walls outside of the vessel. The second heat exchanger includes a second upper passage and a second lower passage, such that the second lower passage is in communication with the second upper passage. A collection chamber receives the combustion gases from the first lower passage through the first outlet. The collection chamber includes a collection chamber divider which directs the combustion gases into the second lower passage through a second outlet. The combustion gases reenter the collection chamber from the second upper passage through a second inlet.