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Express boilers were water-tube boilers with small diameter tubes (typically 2" or less), so as to have the greatest ratio of heating area to water volume.
Other "large tube" boilers, such as the Stirling boiler, had tubes of 3" and over.
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Pages in category "Express boilers"
The following 12 pages are in this category, out of 12 total. This list may not reflect recent changes.