| 摘要 |
<p>A baking oven with circulating hot gas has at least two separately regulated hearths; the hot gas ducts connected to the top and bottom of each hearth all lead into a common gas duct. Each hearth has its independent thermostat for regulating the dampers connecting that earth to the main gas circulation system. All these dampers are connected to a common drive system, operated by a single actuator. The thermostats in the separate hearths operate switching elements for the actuator; switches are also operated by the guide system. These switches ensure that, when the system is changed from the position in which all the dampers are open, the dampers of individual hearths are closed, but one set of dampers is always open to allow the gas to continue to circulate. Since the hot gas continues to circulate, a build up of heat which can damage the burner is prevented.</p> |
