| 摘要 |
<p>Bakers oven has a working chamber and a spaced insulated outer housing from which heated air is drawn by a fan into a first duct extending across the top of the oven, and the re-circulated through a return duct to the bottom of the chamber. There is a burner within the duct and fresh air is also admitted, the combustion products being mixed with the re-circulated air. Overheating of the first duct which would cause non-uniformity of the working chamber temperature is prevented by the cooling of the outer walls of the duct by the circulating gases. The inner walls are protected from the burner flame by the mixture of fresh air and circulating gas which is drawn past the burner. The walls of the duct are never more than 100 degrees hotter than the chamber. The floor of the oven is unobstructed and is at ground level to facilitate loading.</p> |
