Downpipe (steam boiler)
Downpipes are part of a natural circulation boiler . They always lead vertically down from the upper drum and are either linked to the lower drum or to a distribution collector. In the downpipes the water always flows downwards, which in return flows upwards in the riser pipes, which are heated. Downpipes are always mounted on the outside of the boiler, are much larger in cross-section than riser pipes and are generally unheated.
interpretation
The hydraulic balance of forces between downpipes and riser pipes is determined and these are brought into equilibrium. In the riser pipe (see figure no. 3), a part of the mass flow is evaporated by the supply of heat and this increases the specific volume, i.e. the density of the water falls; this creates buoyancy forces and the water in the riser pipe is accelerated. In return, water is sucked from the upper drum (see illustration no. 5) through the downpipes into the distribution header. In the natural circulation boiler, the entire downpipe cross-section should be constructed at least a quarter to half in such a way that the total cross-section of the downpipes is 25–50% of the cross-section of all heated risers. Larger downpipe cross-sections increase the reliability of the natural circulation system, since larger mass flows are in circulation and increase the cooling effect on the evaporators.
Individual proof
- ↑ Markus Franz: Steam generator ( Memento of the original from April 13, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
