Presently about 0.7 Mio small-scale biomass boilers are sold in Europe per year and until 2020 an increase to 1.6 Mio is expected whereas wood chip boilers are one main technology. With these wood chip boilers the fuel feeding systems applied are still a considerable weak point. They are responsible for 80 to 90% of unexpected plant shutdowns, increased emissions and reduced efficiencies. Moreover ...