To provide a method for performing take out, cleaning and filling of thermal storage medium semi-automatically in a series of systems, and a heat accumulator constructed to perform that method.

Flexible discharge pipe of an ejector type air carrier 13 coupled with a dust collector 15 is inserted into a heat accumulator and thermal storage medium 25 is taken out and carried to the dust collector 15 where dust is separated from the thermal storage medium. The thermal storage medium is then thrown into a cleaner 21 and a hopper 22 is charged with cleaned thermal storage medium which is then carried by an ejector type air carrier 14 and a flexible filling pipe is inserted into a heat accumulator 7 and filled with the thermal storage medium thus cleaning and filling the thermal storage medium of the heat accumulator. The heat accumulator 7 for combustion burner comprises a discharge pipe 23 for taking out the thermal storage medium 25 and a filling pipe 24 being filled with the thermal storage medium wherein the discharge pipe 23 is coupled with a vacuum pump 19 through the dust collectors 15 and 17 and the filling pipe 24 is coupled with a tubular carrier (an ejector type air carrier 14 in the drawing).