| 摘要 |
<p>The plant effects uniform heat distribution by the forced and powerful recycling of hot air. A fan may be used to create the air flow, being positioned to direct the flow through a long straight duct. At its output end the duct may fork to direct two sub-flows back to the fan, to form a double closed hot air circuit. The circuit may be completely enclosed beneath the casting bed, and the air may be heated by a burner which uses liquid or gas fuels. The burner treats the air at the duct inlet, its function being controlled by the temp. of the circulating air.</p> |
