To save time a contractor's fit for purpose burner (usually a propaneburner) supplying large amounts of warm air at low temperature can be used.
为了节省时间，可采用在低温下供应大量暖空气的承包商适用的烧嘴（通常是丙烷烧嘴）。
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The way this burner system melts metal is simply by pushing the flame exit port up against the hole in the furnace which ordinarily would hold the propaneburner (or air blast on a charcoal furnace).