The principle of operation and advantages of mine solid fuel boilers


Cur­rent­ly, most own­ers of pri­vate hous­es have gas heat­ing. How­ev­er, sit­u­a­tions often arise when it is not pos­si­ble to con­nect to the cen­tral gas pipe. Then sol­id fuel boil­ers, pow­er­ful and reli­able heat­ing devices come to the res­cue. You can heat wood or coal both in a pri­vate house and in the coun­try. At a cost, this type of heat­ing will be more expen­sive in com­par­i­son with gas heat­ing. In terms of their tech­ni­cal para­me­ters and man­u­fac­tura­bil­i­ty, mod­ern mod­els of sol­id fuel heaters are prac­ti­cal­ly not infe­ri­or to oth­er types of boil­er equip­ment.

Thanks to mod­ern tech­nolo­gies, man­u­fac­tur­ers have man­aged to achieve a sig­nif­i­cant dura­tion of the com­bus­tion process in sol­id fuel units. The heat­ing sol­id fuel boil­er of long burn­ing is by far the most eco­nom­i­cal and effi­cient type of boil­er equip­ment. The undis­put­ed lead­ers in this class are mine-type sol­id fuel heat­ing boil­ers. Such equip­ment has a sim­ple design, so it is not uncom­mon for peo­ple to try to make a mine boil­er on their own.

The principle of operation of the mine-type boiler. Design features

Among long-burn­ing heat­ing boil­ers, mine-type units stand out for their unpre­ten­tious­ness to fuel qual­i­ty. The con­di­tion is impor­tant, giv­en the fact that oth­er sol­id fuel heaters are more capri­cious in terms of fuel choice. Tech­no­log­i­cal­ly, it is allowed to use logs for the fur­nace of the boil­er, the mois­ture con­tent of which exceeds 40–45%.

A mine sol­id fuel boil­er is able not only to digest raw fire­wood, but also to pro­duce the nec­es­sary heat for a long time. Between the next load­ing of fuel, as a rule, 12 hours or more pass. There are mod­els where these fig­ures are even high­er.

The unit got its name due to the design fea­tures. The com­bus­tion cham­ber or fur­nace in this device looks like a mine. In units of this type there are two mines: fuel and heat exchange cham­ber. In the fuel cham­ber, the fuel is not locat­ed in a hor­i­zon­tal posi­tion, but is loaded, as in a well, lay­er by lay­er. Com­bus­tion in such devices is car­ried out from the bot­tom up, so these devices are also called units with low­er com­bus­tion. Let’s see how it looks in prac­tice:

  • just before lay­ing, a hearth is cre­at­ed on the grate;
  • the main book­mark is already laid on the burn­ing fuel, in lay­ers, from above.
  • a con­stant flow of air mass does not allow the upper lay­ers of the fuel to flare up;
  • under its own weight, fire­wood sinks down, tak­ing the place of burnt logs;
  • fire­wood locat­ed in the upper part has time to dry out dur­ing the oper­a­tion of the boil­er;
  • at the very bot­tom of the fuel mine, in the absence of oxy­gen, pyrol­y­sis occurs, the process of for­ma­tion of wood (pyrol­y­sis) gas.

The sec­ond is the com­bus­tion cham­ber or heat exchange shaft, which is the zone where the main com­bus­tion process takes place. Pyrol­y­sis gas enters the mouth of the sec­ond fur­nace, which is the main source of ther­mal ener­gy.

For ref­er­ence: Pyrol­y­sis is the process of gen­er­at­ing a gaseous sub­stance dur­ing an exother­mic reac­tion with wood fuel. In the absence of oxy­gen, a volatile gaseous sub­stance is released dur­ing the smol­der­ing process, which then, upon con­tact with oxy­gen, releas­es intense heat.

The fur­nace shaft may have a dif­fer­ent design. Some mod­els of heat­ing devices have a heat exchange shaft with a flat heat exchang­er. Often in the design of the heat­ing unit there is a water-heat­ing heat exchang­er or a fire-tube heat exchang­er installed direct­ly in the fur­nace shaft. This type and arrange­ment of heat exchang­ers is the most effi­cient. In order to get a real idea of ​​​​how a mine boil­er is arranged, just look at the draw­ing — a sec­tion of the device.

Hot sec­ondary air is sup­plied to the com­bus­tion cham­ber to increase the inten­si­ty of com­bus­tion. The walls of the mouth of the com­bus­tion cham­ber are lined with fire­clay bricks, thanks to which the high­est pos­si­ble tem­per­a­ture in the fur­nace is achieved. Fire­clay brick not only con­tributes to bet­ter after­burn­ing of pyrol­y­sis gas, but also pro­longs the per­for­mance of boil­er equip­ment.

It has already been not­ed above that this type of heat­ing boil­er equip­ment copes well with low-qual­i­ty fuel. Due to the prin­ci­ple of oper­a­tion of heat­ing equip­ment of this type, fire­wood has time to reach the required humid­i­ty para­me­ters. Con­den­sate, which is typ­i­cal for units of the clas­si­cal type, emit­ted in large quan­ti­ties by wet fire­wood, is not a hin­drance for mine devices. Due to the high per­for­mance, the effi­cien­cy of such units is 75–80%.

The main advantages and disadvantages of mine-type boiler equipment

For a coun­try house or a coun­try guest house, this type of heat­ing equip­ment is a real find. It is not always pos­si­ble to get the ide­al fuel to use. Dry fire­wood in the cold and damp sea­son is a rather rare phe­nom­e­non. For oth­er heaters, this state of fire­wood can cause poor per­for­mance of heat­ing equip­ment. Mine heat­ing devices do not suf­fer from such short­com­ings.

Hav­ing installed such heat­ing equip­ment in your home, you get the fol­low­ing ben­e­fits:

  • the unit runs on almost any type of sol­id organ­ic fuel;
  • units are able to oper­ate in dif­fer­ent oper­at­ing modes (wide pow­er range);
  • equip­ment is eco­nom­i­cal. One book­mark is enough for 12–24 hours;
  • long and con­tin­u­ous oper­a­tion through­out the heat­ing sea­son;
  • units of this type are ener­gy inde­pen­dent;
  • sim­plic­i­ty of design and ease of main­te­nance (ash is removed dur­ing oper­a­tion of the unit);
  • high lev­el of safe­ty of the oper­at­ing unit.

On a note: Assess­ing the advan­tages of mine-type boil­er equip­ment, one should not for­get that, like any oth­er boil­er, this unit requires com­pe­tent pip­ing. Oth­er­wise, you risk los­ing all the ben­e­fits of this equip­ment.


Oth­er dis­ad­van­tages of this type of boil­er equip­ment include the sim­plic­i­ty of its design. Here you have to be care­ful and atten­tive! Incor­rect inter­pre­ta­tion of the main para­me­ters of the equip­ment and super­fi­cial knowl­edge of the prin­ci­ple of oper­a­tion of mine-type boil­ers can lead to unpleas­ant con­se­quences.

At first glance, the design of the heat­ing device is sim­ple and straight­for­ward. Many try to make such equip­ment on their own. Attempts are not always suc­cess­ful due to the fact that it is very impor­tant to cor­rect­ly and accu­rate­ly posi­tion the heat exchang­ers. In the com­bus­tion cham­ber, the tem­per­a­ture reach­es 450–5000With and if the water tube heat exchang­er is locat­ed low, your boil­er will boil instant­ly, which will lead to sad con­se­quences.

Depend­ing on the design of the com­bus­tion cham­ber, heat­ing devices are dis­tin­guished into the fol­low­ing types, accord­ing to the names of the cre­ators. The main part of the heat­ing units used in every­day life are Khol­mov’s boil­ers and Efi­mov’s heat­ing appli­ances.

How to heat a mine-type boiler

Like any oth­er type of boil­er equip­ment designed for heat­ing res­i­den­tial facil­i­ties, a mine boil­er has its own sub­tleties and nuances dur­ing oper­a­tion. The first and most impor­tant thing for the nor­mal oper­a­tion of the unit is the qual­i­ty of the fuel, and how the fire­wood is loaded into the fuel cham­ber. The high ther­mal effi­cien­cy of a sol­id fuel mine boil­er is achieved through prop­er stack­ing of fire­wood. Prop­er­ly laid fuel will not only ensure max­i­mum work­ing effi­cien­cy, but also reduce the like­li­hood of smoke in res­i­den­tial premis­es.

The qual­i­ty of fuel stack­ing deter­mines the dura­tion of com­bus­tion and, accord­ing­ly, the dura­tion of the oper­a­tion of the heat­ing unit.

On a note: the lack of nec­es­sary skills leads to the fact that most con­sumers are not able to prop­er­ly use the heat­ing device. Instead of the gas gen­er­a­tion mode, mine boil­ers oper­ate in the nor­mal mode. Accord­ing­ly, the effi­cien­cy of such a unit is extreme­ly low.

In order to prop­er­ly use a shaft-type heat­ing device, it is enough to learn a sim­ple algo­rithm of actions.

  1. The ini­tial igni­tion of fire­wood in the tra­di­tion­al way.
  2. After 15–20 min­utes, the boil­er will be able to reach its nom­i­nal pow­er.
  3. After the boil­er enters the oper­at­ing mode, the rest of the fire­wood is loaded into the fuel shaft and goes into the pyrol­y­sis mode of oper­a­tion.

Prop­er­ly select­ed and stacked fire­wood is a guar­an­tee that the boil­er will work for a long time, pro­vid­ing your home with heat.

As for the fuel itself, much depends on the imag­i­na­tion and finan­cial capa­bil­i­ties of the own­er of the house. How­ev­er, despite the fact that shaft-type heaters are omni­vores, the effi­cien­cy of the boil­er direct­ly depends on how you heat the boil­er.

Fuel bri­quettes, wood­work­ing waste, pel­lets go into the boil­er fur­nace. Bri­quettes and pel­lets are con­sid­ered an elite type of fuel, but their price is much high­er than the cost of ordi­nary fire­wood. Espe­cial­ly if we take into account the unpre­ten­tious­ness of mine boil­er equip­ment in terms of fuel resource. Fire­wood is the main fuel mate­r­i­al for mine boil­ers. Dur­ing oper­a­tion, it is nec­es­sary to make at least half of the book­mark from fire­wood.

On a note: it is bet­ter to use hard­wood fire­wood for heat­ing the boil­er. Pine and spruce logs have a high resin con­tent, which can lead to the for­ma­tion and accu­mu­la­tion of tar on the walls of the com­bus­tion cham­ber.

Method of stacking firewood in a mine boiler

Hav­ing dealt with the prin­ci­ple of oper­a­tion of shaft-type heat­ing devices, with the require­ments for fuel, you need to pay atten­tion to the meth­ods of lay­ing.

The most fre­quent cas­es that own­ers of mine sol­id fuel boil­ers have to deal with are asso­ci­at­ed with hang­ing fire­wood in the fuel cham­ber. The rea­son for this phe­nom­e­non is the wrong book­mark. Tak­ing into account the prin­ci­ple of oper­a­tion of the mine boil­er, where the main com­bus­tion occurs in the low­er part of the device, fire­wood should smooth­ly fall down under its own weight.

Fail­ure to fol­low the rec­om­men­da­tions for lay­ing fire­wood in this case is fraught with a sud­den inter­rup­tion of the main process — fuel com­bus­tion. Before start­ing the oper­a­tion of mine units, the fol­low­ing rec­om­men­da­tions should be fol­lowed:

  • logs intend­ed for lay­ing should be small­er, a few cen­time­ters less than the perime­ter of the fuel mine;
  • fire­wood must always be laid across the shaft, and in no case along it;
  • the dri­est logs are placed at the very bot­tom, while damp fire­wood can be placed at the top.


Some sim­ple tips will help you achieve the nor­mal oper­a­tion of your boil­er. One load of fire­wood, if all the book­mark rules are fol­lowed, should be enough for 12 hours. The boil­er will work inde­pen­dent­ly all this time, with­out requir­ing your par­tic­i­pa­tion.


Min­ing sol­id fuel boil­ers from the entire range of sol­id fuel heaters are the most con­ve­nient, most effi­cient and most unpre­ten­tious in oper­a­tion. For each of us who has our own dacha or coun­try house, this type of heat­ing equip­ment will be the best engi­neer­ing and tech­ni­cal solu­tion.

The con­sumer is cap­ti­vat­ed in terms of the choice of heat­ing equip­ment by the rel­a­tive­ly afford­able price of mine boil­ers, a min­i­mum of com­plex devices and mech­a­nisms in their design.

For the cat­e­go­ry of con­sumers who want to get autonomous home heat­ing, sol­id fuel long-burn­ing shaft-type boil­ers will pro­vide a lot of free time, a high lev­el of com­fort in the house.


Leave a Reply

You May Also Like