A vertical vertical tube boiler or vertical multitubular boiler is a vertical boiler where the heating surface consists of several small fire tubes, arranged vertically.
This boiler is not common, due to its weakness with excessive wear and tear in service. The more common form of vertical boilers, which are very similar in outer appearance, instead use a flue tube and a single water-filled tube. Other forms use horizontal fire tubes, even where this adds to the complexity, such as the Cochran boiler.
Where sustained high evaporation capacity (ie power) is required, vertical tubes are used, but rarely. These cases are mostly for locomotives, either railroad locomotives or road steam carts.
Video Vertical fire-tube boiler
Weaknesses
In any boiler, one of the most vulnerable locations for disposal of tubes and plates is around the water surface, where agitation and boiling are most active. This is especially true when this level is also part of the heated surface, where boiling is most intense (the tubular water pipe design also tries to drown the surface that is heated directly beneath the surface of the water, for the same reason).
In the design of this boiler, the affected area of ​​erosion is the top of the fire tube. Although such tubes are usually designed to be replaced easily, their working life is relatively short.
Horizontal tube
Horizontal fire tubes are otherwise more efficient than vertical. For that reason, and to avoid the problem of tubular erosion with open vertical tubes, many of the multi-tubular vertical boilers are arranged with horizontal tubes. This could be a parallel bank, such as a Cochran boiler, or another radial like for Robertson.
Tubes submerged
To avoid the problem of open flame tubes above the water surface, the boiler submerged multi-tube boiler can be used. The upper boiler shell is extended upward in the annular ring, so it always keeps the entire length of the tube submerged. Used in steam carts and the like, where water levels can be disrupted as vehicles climb the hill.
The relatively rare Fowler steam cart uses a boiler of this form. The main barrel of the boiler contains a firetub nest that curves between the firebox without interruption and the large open space that forms the chimney contains a five-spiral super spiral tube. Both tubeplates were twitching inward, making them strong enough to not have to stay. The firetubes are curved to 'cause a vortex in hot gas as they rise', to allow free expansion by heat and also to allow a perpendicular connection between the tube and the tubeplate.
The external belt of the channel plate is glued around the outer shell at the upper tubeplate level forming additional vapor and water chamber, which is connected beneath the water surface with a hole drilled through the shell. Boiler water level operations are always maintained in this belt chamber, keeping the tube fully submerged. The disadvantage of this system is that the water surface area is reduced, leading to an increased priming risk and also the need to maintain the boiler water level carefully; the volume to high ratio becomes smaller in the belt region, a relatively small change in water volume produces a major change in the rate.
A similar approach can be seen as a top bulge around the vertical boiler of the reconstructed GWR railmotor.
This design has also been suggested for the use of model engineering. In this case the belt is formed inside the boiler shell, with a tubeplate of the inherited diameter inside.
Maps Vertical fire-tube boiler
Stanley steam car
Some steam cars, including Stanley and Chelmsford, use vertical multi-tube boilers; Stanley's design became very famous.
Stanley boilers are built from a smooth copper tube shell, 13 1 / 2 inch (340 mm) in diameter and < span> 1 / 16 inch (1.6 mm) thick. Many solid 2-inch (split) / 2 spaces, leaving very small water volumes between them and high heating rates. surface to volume, for a rapid increase in vapor. The boiler construction is unusual, because steel tube plates are only held in place by friction and the tubes are only slightly extended to those with tapered drift. Outside of the outer part of the boiler shell there are three steel rings whose heat is shrinking, the compressive stress holding the pipe plate. For additional strength, the boiler shell is further wrapped in a helical layer of piano wire. When the boiler is fired by a flat liquid fuel burner, a closed fire box is not required.
See also
- vertical cross-tube boiler
- Boiler vertical with horizontal fire tube
References
Source of the article : Wikipedia
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