Boiler

Examples

a boiler of Central heating, makes it possible to distribute heat in various buildings. The restitution of heat is carried out using Radiateur S or of convectors. The liquid employed is generally water. A second circuit can ensure medical warm water (shower, etc). Smoke of the traditional boilers contains water with the state vapor produced during the reaction of combustion (see NCV).
the boilers with condensation, a little more expensive, are equipped with an additional exchanger on the level of the rejection of smoke where the water of heating circulates before its introduction into the boiler. This makes it possible to condense and thus to recover the latent energy of condensation contained in water with the state vapor of smoke (see GCV), giving the illusion of a " Output " superior with 1. These boilers are interesting only when the temperature of introduction into the boiler is low (approximately 40°C instead of the 60°C usual). The lifespan of a boiler of good mark and carefully maintained each year can exceed 35 years; whatever the mark, it lasts seldom less than ten except negligence or choice of replacement by a more powerful model.
the pulsatory boilers which obtain an output close to the 111% NCV and rest on a principle of combustion different from the traditional boilers.
a Locomotive boiler of with vapor heating of water until the stage of the vapor in overpressure, this vapor while slackening in pistons delivers a mechanical force which is used to move the engine.
systems of cleaning vapor in vogue in the Years 1990 - 2000 comprise a boiler with not completed producing the steam.
a boiler used to provide to an industrial process, heat and/or force.
a Nuclear plant uses the principle of the boiler. The nuclear reaction heats a fluid, which transports thermal energy to a turbine involving a Alternateur.

Types

One distinguishes the boilers mainly by their internal architecture

with fire-tube

It is historically the first type of construction, the gases resulting from combustion in the hearth, circulate then through the mass of the Caloporteur, generally of water by means of tubes, before being evacuated by the Cheminée. The first models used a vertical circulation, easier to realize, because of Convection gases, but thereafter, one produced boilers with a horizontal arrangement, more adapted, with the use for the Railroad or the Navigation.

with water tube

In this Construction, it is the Caloporteur which circulates in combustion gases. The advantage of this formula is especially safety not to have great quantities of water in the boiler, which could in the event of mechanical rupture, to even involve an explosive creation of vapor. They moreover were more often equipped with superheater, which let circulate the vapor in the high part of gases, thus increasing the temperature of this one with constant pressure.

The boilers can use various fuels and/or energies: (Wood, coal, Fuel, Gas, electricity…) For the boilers using a fuel, the circulation of combustion gases can be natural (by natural convection) or forced (ventilator)

with forced circulation

In this type of boilers, the circulation of water in the tubes is ensured using a pump. This configuration is necessary when the height of the tubes is low or when the pressure is very high c.a.d that the difference in density between the liquid and the vapor is insufficient to create a natural circulation (only by difference in density).

with natural circulation

The circulation of water in a water-tube boiler is very important to avoid the formation of the dry zones where metal is likely to melt under the effect of heat (radiation). Into the boilers with natural circulation, auxiliary water (cool water) is introduced into a higher balloon, considering the density of this water is larger than that of already existing hotter water, it will go down naturally by difference in density. During this descent, it starts to take heat jusqu to reach a zone or it becomes very hot and its density much lower, in this case, it goes up is cost with the balloon into which it was introduced. This movement traversed by water (one can imagine the trajectory of only one drop) was not obtained using a pump: for that, it is called: natural circulation.

See too

Polarchem Descaling of boiler

External bonds and documents

heating - Energie+ - very complete Publication of the UCL (support of the D.G.T.R.E.)

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