thermic syphon

plural thermic syphons

1. alternativeAlternative form of thermic siphon.

   […]combined heating surface is 6,151 sq. ft. (tubes, 530 sq. ft., flues, 3,275 sq. ft., firebox, with arches and thermic syphons, 415 sq. ft., and superheater 1,931 sq. ft.);[…].

   1941 January, “Recent North American Locomotives”, in Railway Magazine, page 27

   1 more example

   The response to firing is remarkable, and though the 280 lb. pressure seems more in the nature of a reserve for emergencies than a continuous working figure, even with the present-day apology for coal it seldom fell below 250 lb., and could always be brought up to blowing-off point with little difficulty. To this liveliness of steaming the thermic syphons are doubtless the chief contributory.

   1947 January and February, Cecil J. Allen, “British Locomotive Practice and Performance”, in Railway Magazine, page 39