Basic furnace
According to § 2 No. 13 of the ordinance on small and medium-sized combustion systems, a basic furnace is a “single- room combustion system as a heat storage furnace made of mineral storage materials that are handcrafted on site”.
Often a fireplace is also referred to as a basic stove that does not have a fire grate, as it is only fired with wood. The wood ash collects on the floor of the stove and forms a bed for the embers. In a well-designed stove, little ash remains after the wood has burned, so that a basic stove with a sufficiently large combustion chamber only needs to be cleaned after 50 or more fires. The charcoal is completely burned to carbon oxides and voluminous carbonate skeletons in the ash to fine oxide powder.
Typical basic or Grundbrandöfen are made of firebricks brick and clay Wärmespeicheröfen which should heat the boiler room to the largest possible extent by the delivery of radiant heat. In contrast, an air heater or convector heats the room with a flow of warm air.
A coal fire needs the air draft from below, which is made possible by a fire grate, since the combustion process requires the supply of more oxygen due to the high calorific value.
In contrast, the embers of a wood fire should lie in the ash heap, since under these conditions the combustion temperature necessary for clean combustion is maintained. When burning wood on a fire grate, the burning process works as long as flames beat out of the wood. In the glow phase, however, the air flow cools the material to be glowed. As a result, the combustion of wood on a fire grate remains incomplete and harmful combustion products ( creosote ) arise.
When burning wood in a basic oven, if the air supply is guaranteed, after the logs have been placed on the burning kindling, further regulation of the air supply is unnecessary because it regulates itself automatically through the combustion process. If the combustion process is hindered by throttling the air supply, the combustion is not complete, with the result that the degree of efficiency deteriorates and pollutants as well as damage to the stove and fireplace can occur and the risk of fire is increased.
Since basic stoves with a metal jacket without a fireclay lining have a lower heat storage capacity than a tiled stove, the embers are not kept as optimally warm as in a brick-built basic stove.
Mode of action and function
The larger the outer surface of the basic furnace (including the flue gas pipe), the greater the proportion of radiation in the furnace's total heat output.
The sum of the heat radiating surfaces forms the basis for the corresponding heating output of the basic furnace.
If the stove is the sole source of heat as a single fireplace, the nominal heat output of the stove must correspond to the heat demand of the rooms to be heated.
The specific nominal heat output of a furnace can be roughly determined by multiplying the inner heating surface (surfaces in contact with the combustion chamber and the flue gas) by 850 W / m². The calculation is based on the basis for interior fittings (combustion chamber and draft system) according to the imperial principles of the 1930s and can only be used to a limited extent today in this form.
A basic furnace has a very sluggish heat behavior and requires long heating times. A properly built basic oven usually needs two to three hours before the heat can be felt on the surface. The more sluggish the stove, the longer it can store the heat so that reheating is less frequent.
history
Orders from Count Palatine Karl IV. From 1772 also served to prevent a fire in connection with domestic fireplaces. According to the simultaneous building regulations, no more wooden chimneys were allowed to be erected, no more wooden hoses were allowed to be installed, which had to lead the smoke from the fireplace to the fireplace, just as it was forbidden to lead stovepipes out of the window.
Individual evidence
- ^ Alfred Eisenschink: Fire in the oven - happiness in the house , Graefelfing, 1999
- ↑ A. Eisenschink, p. 31f
- ↑ A. Eisenschink, p. 46
- ↑ A. Eisenschink: p. 17f
- ^ Franz-Josef Sehr : The fire extinguishing system in Obertiefenbach from earlier times . In: Yearbook for the Limburg-Weilburg district 1994 . The district committee of the Limburg-Weilburg district, Limburg-Weilburg 1993, p. 151-153 .