Apparatus for cleaning blast-furnace exhaust gases

A gas-cleaning apparatus for a high-pressure furnace comprising:

• duct means connected to the head of said furnace for conducting an exhaust gas therefrom, the head of said furnace having a back pressure;
• a separator connected to said duct means for separating dust from said exhaust gas;
• a differential-pressure washer having an upstream side connected to said separator and receiving said exhaust gas therefrom;
• a main conduit connected to a downstream side of said washer;
• an expansion turbine unit connected to said main conduit for expanding gas traversing same, said differential-pressure washer being located ahead of said expansion turbine unit and washing gas from said duct means prior to the passage of the gas through said expansion turbine unit;
• a bypass conduit connected to said differential-pressure washer for conducting gas therefrom around said expansion turbine unit;
• a quick-opening valve in said bypass conduit and a quick-closing valve in said main conduit for substantially concurrent operation to switch over flow of gas from said main conduit to said bypass conduit;
• means connected to said quick-opening and quick-closing valves fo simultaneously operating same;
• a pressure-control valve connected to said bypass conduit for regulating flow therethrough;
• and
• control means connected to the head of said furnace and responsive to the pressure at the head of said furnace and connected to said expansion turbine unit and to said pressure-control valve for operating said unit when said main conduit is traversed by gas and operating said pressure-control valve when said bypass conduit is traversed by gas to maintain said back pressure substantially constant.