| 摘要 |
A lost mold for the casting of the ferrule, nozzle or mouthpiece of a chimney or smokestack consists of a light-weight relatively thin material which can burn off, wear or degrade in use and which is stabilized in a casting chest or box with sand for the casting of the concrete body adapted to form the ferrule or mouthpiece. The lost mold permits the casting of a draw-promoting device for a chimney by masons at the site of erection thereof and hence eliminates the need to transport massive bodies long distances. It also eliminates difficulties encountered with the shaping of the mouth of a smokestack or chimney by masons or chimney specialists.
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