Abstract: The gas-cleaning apparatus for a blast furnace operating under pressure using a differential-pressure washing arrangement whereby the differential-pressure washer comprises at least one annular gap with an annular-gap passage and an axially adjustable body received in the annular gap washer. The nozzle is disposed upstream of the annular-gap washer to spray the washing liquid into the gas which is accelerated through the annular gap. The position of this body is controlled in response to the gas pressure within the head of the blast furnace. The annular gap of the washer diverges in the direction of flow of the gas and the body has a complementary shape so that the gap width remains generally constant although its flow cross section increases with the diameter of the annular gap in the direction of flow of the gas.

Abstract: An apparatus for cleaning the exhaust gas of a high-pressure blast furnace comprises a coarse-particle separator, a prewasher and a differential-pressure annular gap washer traversed in succession by the gases. The exhaust gases can be passed through a main duct provided with an expansion turbine or through a bypass duct around the expansion turbine. The expansion turbine unit controls the back pressure at the blast furnace while a separate control circuit is provided to operate the differential-pressure washer with optimum efficiency. A quick-closing valve in the turbine-supply line and a quick-opening valve in the bypass line permits rapid switchover, a pressure-control valve in the bypass line maintains a constant backpressure at the blast furnace when the expansion turbine unit is shut down.