Combustion air control in an in-line flame arrestor
 Mounted on the entrance end of a firetube, the two screen elememts of an in-line flame arrestor are linearly spaced along a tubular core. A common aperture through the core wall is formed between the two screens. Combustion air directed through either, or both, screen elements enters the core through the aperture in the core wall to supply a fluid-fuel burner mounted within the core both primary and secondary portions of the combustion air. The effective size of the aperture is adjusted by a movable, internal sleeve within the core with linkage to the fuel supply system of the burner. 
Combustion Engineering, Inc.
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F23N F23D F23C
inventional additional inventional
James D. Max L. William R.
Hunter Lewis Willis