| 摘要 |
<p>Process for ensuring and maintaining the quality of an observation hole, esp. in a blast furnace where an observation device is employed, or an optical measurement made, along the sighting axis of a small hole (e.g. with a dia. below 10 mm) made in a screen inserted between the device and the interior of the zone being observed; and where a porthole is located between the device and the screen. A current of dry compressed gas is blown between the porthole and the screen, the gas escaping via the side of the observation hole opposite the porthole, and the side of the screen facing the zone being observed is subjected to a cleaning operation e.g. by scraping. The gas is pref. used continuously whereas the cleaning is discontinuous. Used in observing or monitoring the temp. distribution across the top of the charge in a blast furnace, the existence of hot spots, etc., esp. when a high gas pressure exists in the furnace. The current of compressed gas keeps the porthole clean.</p> |
