A system that can handle coarse chips too
Every ETA wood chip conveyor system is well thought out, tried, tested and designed for the toughest use: the transport of coarse, uneven wood chips. So that pieces of wood of up to 12 cm can be transported, all parts must work together perfectly. That starts already in the bunker. The wood chips reach the screw via generously designed open troughs. In the process, a relief plate prevents the material from exerting too much pressure on the discharge screw and thus enables fill heights of up to five metres. Bottlenecks are avoided in the enclosed trough channel thanks to the spacious discharge connections. A smooth material transport is supported by the progressive screw, which loosens the wood chips even more. Even the installation is easy thanks to the modular design. The screw modules with sizes of 12.5 to 200 cm are produced and aligned in automated machines. The specially shaped trough channels only have to be screwed together.
Even more flexible thanks to flue gas recirculation.
ETA wood chip systems offer the advantage that the operator can use wood chips of different qualities. Not just in terms of size. Flue gas recirculation, which is a tried and tested element from large plants, is used for very dry fuels such as dried wood chips (< 15% water content [M]), miscanthus or also pellets. Flue gas recirculation is optional and is activated on request. The combustion temperature in the degassing zones is therefore kept exactly at the desired temperature level – above 800 °C, but below 1,000 °C. So, on the one hand, all components of the fuel are completely separated, and on the other the thermal load on the components is minimised, i.e. the lifetime of the boiler is increased. Combustion temperatures that are too high can also lead to undesirable slag formation.
The boiler that thinks with you...
Many sophisticated systems are at work in the ETA HACK: replaceable knives simply cut pieces of wood which are too long. This allows the boiler to also process coarse industrial wood chips. A lambda probe "detects" the condition of the combustion material, so that the fuel feed and the air supply can be automatically adapted to the wood quality. And the single chamber rotary valve, developed and patented by ETA, reliably prevents the fire from reaching the fuel store.
... and is economical in the way it uses energy
The spur gears used by ETA feed the wood chips with less effort than regular screw drives. So the power consumption is reduced by around a third. And because a clean boiler works more efficiently, the whole boiler is automatically de-ashed - from grate to heat exchanger.