WNS Horizontal Gas Boiler: The Effect of the Boiler Drum’s Thermal Expansion on the Base
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The total length of the boiler drum is over four meters, with the distance between the front and rear legs being just over three meters. The legs are welded to I-beams; the front leg is fixed to the I-beam, while the rear leg is movable. It was calculated that when the temperature rises from 0 to 200°C, the expansion is 5 mm. Is it necessary to make the connection between the rear leg and the I-beam in the form of a sliding rail? Is 5mm necessary? How long does a boiler generally need to be before sliding rails are considered? It’s still the same old problem: there’s no standard, so it’s impossible to address those who cause the issues
An aside: due to the numerous problems that arose during actual production, someone suggested using a cylindrical hole in combination with bolts to enable sliding, but this approach couldn’t be implemented because there was no standard for it.
①Because of the issue of cracked welds on the base, if you don’t adopt a sliding design, the regulatory authority will eventually point out this problem to you. Considering the process, large and small furnaces can be standardized. ②There are no specific standards; design can be carried out by referring to the patterns of container support types. Boilers ultimately fall under pressure vessels, and can rely on vessel standards. ③In fact, the issue of boiler bases has not received sufficient attention; many boiler manufacturers still use L-shaped feet, and no major problems arise from this, with at most the legs getting damaged during installation.
I suddenly remembered a problem that had been overlooked after extensive calculations: for water-cooled wall tubes subjected to internal pressure, the welding reduction factor for thin tubes (page 60 of 16508). No UT or RT testing is carried out in this case, nor is any magnetic particle or penetrant testing used. The selection of this factor is specified as follows (page 16): 1 for fully penetrative, non-destructive testing; 0.85 for partial non-destructive testing； 100% non-destructive for single-sided butt welding: 0.9; partial non-destructive: 0.8. How should I choose this modification? How is it that some calculation sheets choose 1?
This is the base of my company; I’m sharing it with everyone
This post was last edited by kareale88 on 2019-4-18 at 18:52; a long hole will do.
This is also WNS4, right? Are all four bolts? Typical four-ton boilers have one front foot secured with bolts – are all four of those bolts that large?