Sawdust furnaces are not a new phenomenon, but they are still quite demanded to this day. Such units every year only increase their popularity among the population due to significant advantages. The structural features of wood waste devices contribute to long-term fuel combustion with maximum heat transfer. Heating with sawdust, a cheap and environmentally friendly material, can significantly save by purchasing inexpensive raw materials for heating a private house.
Chimney pots, as they are also called, do an excellent job of heating greenhouses, workshops, service stations, garages and not very large living spaces. The manufacture of such common boilers can be done without much difficulty by hand, after having previewed the drawings and studied the assembly process. As a source material, you can use any improvised containers like old metal barrels, pipes, gas cylinders, of course, without contents, and other similar tanks. Before making the sawdust furnace with your own hands, which you plan to heat in the cold season, we suggest that you familiarize yourself with the design and features of industrial equipment, and based on it draw conclusions about how the boiler should be on wood chips and how to deal with its assembly.
Industrial model
In the modern market of heating appliances, there are many boiler models where wood, or rather, its shredded waste, is used as fuel. Depending on the technical characteristics of the product, sawdust stoves can only heat a house or additionally also farm buildings. There is a standard scheme that allows providing hot water for the heating system and domestic needs, where the main element is a double-circuit solid fuel pyrolysis boiler. The heat output in this case depends on the power of the sawdust boiler, as well as the quality and quantity of the specified fuel.
Advantages of modern units
The main advantages of factory heating appliances for the home are:
- maximum automation of fuel combustion and stable maintenance of the required temperature. Boilers on wood chips independently control how full the storage hopper is from which the sawdust is fed into the boiler. Due to the fact that protective automation is triggered in time, fire augers do not allow the flame to spread back to the hopper;
- automatic regime of ash discharge into a special collection saves owners from stopping the system for manual intervention in the cleaning system. In this case, sawdust boilers stop their work only in case of malfunctions in order to eliminate them;
- the heat generator on sawdust is environmentally friendly, because here combustion is not accompanied by the emission of ash from the pipe into the atmosphere, and the heated air passes several degrees of purification from heavy particles, and only then enters the room. Meanwhile, the ash precipitated by a special cyclone is disposed of without harm to the environment;
- the vast majority of boilers operating on pressed or friable sawdust is characterized by reliable operation and high heat transfer efficiency;
- full automation of the control system, which scans the equipment for malfunctions and signals the operator about possible operational errors, if any.
Cons of factory-built boilers
This type of heat-generating device has practically no drawbacks, except that their cost depending on the brand and model can be very high. Also, sometimes there are problems with the replacement of failed components, which must be ordered from the manufacturer and wait for the delivery of the goods, which is problematic in the heating season, when the system shutdown is very undesirable.
Solid fuel sawdust boiler in action
It's time to familiarize yourself with the technology of the unit, which will allow you to understand the principle of its action:
- The process begins with the automatic feeding of sawdust into the hopper, equipped with a system of moving floors, from where they enter the conveyor.
- Compressed or loose wood material is stored in the hopper until the compartment with the burner for burning sawdust is empty, after which the moving floors come into operation. When the hopper is full, fuel will not be supplied until the tank starts to empty.
- At the next stage, wood shavings from the hopper are fed into the boiler using a screw for wood chips and sawdust.
- After entering the combustion chamber, fuel is burned in full thanks to air blowing. Further, the operation of the boiler is performed continuously according to the same cycle discussed in these four paragraphs.
Home-made design: materials and assembly procedure
So, when we figured out the device and the principle of operation of an industrial design, we can begin to make a mini-household appliance similar in operation. First you need to stock up with the necessary tools and materials from which the stove will be assembled, namely we will need:
- welding machine;
- pipe of available diameter (32 - 56 mm);
- gas outlet pipe (100 mm);
- a set of adjustable and gas keys;
- Bulgarian;
- roulette;
- clock relay;
- thermal sensor;
- explosion-proof valve;
- water pump;
- ball valves (3 pcs) and threaded couplings;
- feed auger;
- ash removal screw (optional);
- metal corner 45 - 50 mm;
- hydraulic cylinder;
- 200 l barrels for ashpit and sawdust (2 pcs);
- electric fan;
- sheet metal (4 mm);
- tow or fum tape.
The working process
The assembly of home-made boilers on sawdust begins from the manufacture of the body and bottom of the unit. Everyone selects the dimensions of the design individually. Using a welding machine, the boiler body is formed without a bottom and covered with a water jacket. Home-made boilers can consist of empty gas cylinders, however, we will focus on the welded version, which will allow us to vary the dimensions and power of the installation.
Next, it is necessary to make stiffeners between the water jacket, and also provide technological holes through which air will be supplied from the fan to the combustion chamber. A “living” bottom is mounted from a metal corner, if it is provided, for which they are cut to a size of 50x25 mm and the rod is mounted for output to the cylinder. When the furnace body on the sawdust is ready, it is mounted on a seat, a screw is installed to remove ash and the container is fixed under it. Now you can mount a fan, a screw that feeds chips, as well as a tank for fuel, and we can say that the sawdust burner is assembled with your own hands.
How to melt a stove
In order to make the work of home-made stoves for sawdust as efficient as possible, it is necessary to correctly burn fuel. Initially, shredded wood is laid in a barrel (or in a “live” bottom bunker) for 75% of its volume, after which a clock relay is activated and the auger feeds the sawdust into the furnace, where they are carefully ignited with gasoline or diesel fuel. Next, turn on the fan.
There is another heating scheme with wood chips, which differs slightly from the previous version, as it fits a simpler sawdust boiler, made by yourself (see photo).
For its implementation, it is necessary to fill the fuel chamber with sawdust three quarters of its volume, while it is recommended that the crushed tree be pressed around a conical pipe. After tamping, the pipe is removed, the heating boiler on the sawdust is closed with a lid and the damper in the chimney opens. Firewood is laid and kindled in the lower part of the furnace, from the heat of which sawdust slowly smolders.
Now you know how to assemble a sawdust furnace with your own hands, how it should work and how to properly heat it. A well-made unit is able to provide economical heating of a small living room or any other outbuildings, and in more detail about the functioning of the potbelly stove can be found in the video attached below.