Abstract: When burning black liquor obtained during cellulose pulp manufacture it is desirable to maintain a constant atomizing pressure. Mere throttling of the liquor supply in order to adjust the combustion to actual heat demand will alter the spray pattern. A pressurized gaseous fluid is injected into the liquor supply conduit, and the amount of this gaseous fluid is governed in response to the actual heat demand. A monitoring device senses the pressure in the supply conduit downstream of the throttle valve, and adjusts the position of the latter in response to the activity caused by the gaseous fluid, so the resulting pressure is maintained at the desired level.

Abstract: Waste liquor obtained when pulping wood can be advantageously burned and used for raising steam, while simultaneously chemicals are reclaimed. Certain waste liquors have a noted tendency to cause deposits in valves and piping, which therefore must be intermittently washed by a neutral fluid. This means an interruption of the supply of fuel to the burner, and even if a furnace usually is provided with several burners the interruption causes a disturbance of the steam production, beside necessitating a considerable amount of labor.The invention proposes a means for supplying liquid fuel and washing fluid simultaneously to each burner by two parallel conduits in such a manner that a simple switch-over will result in the (occasional past) supply conduit and the major part of the burner will be washed, while liquid fuel is supplied through a conduit having recently been washed.