NEO MAKİNA ve MÜHENDİSLİK A.Ş. designs and manufactures automatic stoker combustion systems in which coal is fed automatically by screw. A low-investment, durable solid-fuel solution with minimal operator intervention for steam, hot-water and thermal oil boilers and hot-air generators.
What Is a Stoker Combustion System?
In an underfeed stoker, coal is pushed from the bunker into the combustion retort from below by a screw. As the fuel rises in the retort it dries, gasifies and burns with primary air supplied around the retort; ash overflows the rim into the ash pit. Feed rate and fan output are adjusted automatically to boiler load.
Operating Principle and Design
- Automatic screw feed: Geared drive for coal dosing; timer or thermostat/PLC-controlled operation.
- Optimised retort geometry: Stoker width and depth fixed by field experience; burn-back in the screw, slag build-up and mechanical stress are minimised.
- Air management: Correctly sized combustion fan and air channels around the retort give a homogeneous air-fuel mix; emissions stay below legal limits.
- Materials: Retort and grate elements in high-alloy (2% Cr) cast iron, resistant to thermal stress and wear.
- Thermal compensation: Modular retort structure tolerates thermal expansion; cracking risk and maintenance are reduced.
Advantages
- Efficiency independent of fuel grade: Stable combustion across a wide coal range including low-grade domestic coals.
- Multi-block operation: Several stoker blocks run in sequence or independently for flexible capacity matching boiler load.
- Low investment and operating cost: Simple mechanics, few moving parts, easy spare-parts supply.
- Ease of operation: Days of unattended running depending on bunker size; automatic ash-removal option.
- Retrofit-friendly: Fitted to existing hand-fired or grate boilers for higher efficiency and comfort.
Typical Application Range
- Thermal capacity: 100 kW – 10 MW (depending on number of blocks)
- Fuel: nut-size (10–30 mm) coal; lignite, hard coal; pellets and olive pomace in suitable versions
- Applications: steam and hot-water boilers, thermal oil heaters, heating boilers, greenhouses, dryers, hot-air generators
- Control: thermostatic, timer or PLC-based; O₂ trim option
- Standards: EN 303-5, EN 12952/12953, CE
The NEO MAKİNA Difference
Stoker capacity and number of blocks are set from the boiler's thermal output and coal analysis; bunker, screw, fan and ash system are engineered for the site. Installation, commissioning, combustion tuning with flue-gas analysis and operator training are included.
Frequently Asked Questions
What coal size does a stoker accept?
The ideal size is 10–30 mm (nut coal). High fines content reduces feeding and combustion efficiency; screening or briquettes are recommended.
When is a stoker preferred over a travelling grate?
At low and medium capacity, with limited investment budget and variable coal quality, the stoker is the economical choice. For high capacity a travelling or reciprocating grate is recommended.
Can a stoker be fitted to my existing boiler?
Yes. If furnace dimensions are suitable it is installed through a front-door or base adapter; a quotation follows a site survey.
To size the right stoker for your boiler and request a quotation, contact us.