Abstract: An apparatus for purifying and neutralizing residues from furnaces burning liquid or gaseous fuels comprising a settling tank having an inlet for the liquid containing the residues, at least one oil absorption body in the settling tank, and a clean water tank separated from the settling tank by at least one filter. The pH in the clean water tank is raised, and a filtration unit contains activated carbon between the clean water tank and outlet.

Abstract: A calorific value boiler device for supplying heat to at least one user of heat contained in a heat medium via a first supply line and at least one return line. The device includes a boiler having a blower equipped burner with flue gases discharged in a specific direction and at least two heat exchangers arranged in series to receive the flue gases sequentially in that direction. Also provided is a stratified thermal storage unit for delivering medium to the user via a first supply line. A first line is for transferring heat medium from the first heat exchanger in the series to the top layer of the storage unit. A second line is for transferring heat medium from the bottom layer of the storage unit to the last heat exchanger in the series. A third line is for transferring heat medium from the middle of the storage unit to the first heat exchanger and having a flow cross section at least twice that of the second line.

Abstract: A process for operating a furnace boiler with a firebox having a cooled wall and at least one blowpipe to direct flame into the firebox, and heat exchangers connected to the firebox through which the flue gases flow, consisting of the steps of extracting heat from the flue gases essentially only by the heat exchangers and cooling the wall of the firebox only to the extent that, at maximum burner output, the temperature on the inner side of the wall does not exceed approximately 600.degree. C. and, when the burner output is reduced to about 1/10 of maximum output, the temperature does not fall below approximately 180.degree. C.