We briefly touched upon the features of Kuznetsov’s stoves when we wrote about the types of fireplaces, Russian stoves and open hearths. Now we will pay more attention to this variant of stoves, because “blacksmiths” heat many Russian houses and arouse genuine interest. Igor Viktorovich himself pointed out that he developed the foundations of the correct design of household stoves, which were developed by I.S.Podgorodnikov on the basis of the works of Professor V.E. Grum-Grzhimailo, a Russian scientist-metallurgist.
How do conventional duct ovens work? The movement of gases in them occurs under the forced action of traction. The gas gives off its heat to the brickwork, heats it up from the inside, passing through narrow oven channels. We have to build a high narrow chimney, the stove heats up unevenly, the brickwork can crack. Kuznetsov bell-type furnaces work differently – on the principle of natural, free movement of gases.
These stoves were named “bell” for a reason: inside they have large cavities, hogs, inverted caps, which can be located both horizontally and vertically, one above the other.
As a result, the heated smoke rises, hits the cap, dome, lingers there, and then gradually cools down and falls. Thus, the heat is retained inside the furnace and the contact time of the hot gas with the brickwork is noticeably increased..
This principle of operation can be explained using the example of a rubber glove, which is completely filled with gases in all cavities. In the bell, which as a whole can have a different shape, convection occurs, convective movement of gases in a natural way, according to the laws of nature.
Most often there are two-cap “blacksmiths”. In the lower part of the furnace there is a chamber in which a high temperature is maintained, ensuring the end of the combustion reaction of gases, which are divided into warm and cold. In this case, hot gases are retained in the furnace, and cold gases are gradually removed into the pipe, without cooling the heat exchanger itself.
Advantages of Kuznetsov furnaces:
- The efficiency reaches 93%. For comparison, for traditional Russian stoves this figure does not exceed 70–80%;
- soot in “blacksmiths” burns out, so the stove and chimney can be left unclean for years, which greatly facilitates their care;
- the hoods inside the furnace are voids, this allows you to save on brickwork, which would have to be done by equipping conventional draft channels;
- the stove can be placed anywhere – in the corner, in the center of the room, against the wall. Often “blacksmiths” heat several floors of the house, working on one firebox;
- any kind of fuel can be used in Kuznetsov’s stoves;
- the chimney can be made short, which also leads to material savings;
- uniform heat transfer, the temperature in the house heated by the “Kuznetsovka” fluctuates much less;
- the stove can be easily combined with a hob, fireplace, stove bench – there are a large number of modifications;
- it is possible to build in a hot water supply circuit and hot water heating;
- high efficiency of the ongoing pyrolysis saves on the fuel used;
- masonry lasts longer, less risk of cracking;
- a closed valve at the wrong time will have practically no effect on the cooling of the furnace, because the bell is always filled with hot air, and cold air is pressed to the bottom.
Kuznetsov’s stoves have few disadvantages. First, while it is difficult to find a master who is ready to take on such a project, the work of a stove-maker will cost a lot, there are peculiarities and construction rules. Secondly, the “blacksmiths” have rather big sizes, they are rather massive. However, Russian stoves cannot be called compact either..
During his career, Kuznetsov has developed many options for furnaces operating on the principle of free movement of gases. There are saunas, for heating the house, outdoor (with barbecue), fireplace, bread, cooking, mixed type.
It is recommended to heat Kuznetsovki twice a day to ensure a comfortable temperature in the house. Experts say that for heating a house with an area of 100 m2 15-17 kg of logs per day will be enough.