PURPOSE: To prevent clogging of a fuel supply device and seizure at rotating shaft bearing sections due to heat conduction by rotating a hollow shaft for pneumatic conveyance of a specified fuel and for introducing air for a rotating frame and rotating with chains a fuel stirring machine and an ash discharge device which are connected to the hollow shaft.

CONSTITUTION: A rotating shaft is a hollow shaft 7, and its section a on one side is made a worm gear section 4 for pneumatic fuel conveyance and at the same time its section b on the other side is made the shaft for a rotating frame body 8 which is of a cone shape pointing sideways. In the outer circumference of the section b many air holes 13 are pierced. This holed section is connected to the central hollow section and its end closes the hollow section. The tip end section of the shaft which has the length of this section b is made the section to insert and fit the rotating frame body 8, and a specified position on the outer periphery of the body 8 is covered with a heat resistant metal net 21 for receiving and stopping fine powder of the fuel and secondary combustion. Inside of the outer diameter of the rotating frame body 8 a plurality of semi-circular band shaped fuel receiving pans 17 which have small air holes 16 in their bottom sections are inclined to the front and they are mounted radially, and at the same time from the outer circumference of the large diameter section 18 of the radial mounting arms 19 are collected to the central section and fixed.