| 摘要 |
Arranged within a frame construction formed by horizontal upper bars (3) and vertical side bars is a refractory wall with a cavity (2) for accommodating a bath. The lateral areas of the frame construction are closed off by means of screening plates (5) and the upper side of the wall is closed off by means of a cover plate with a central opening. A hood (7) is placed on the upper part of the frame construction. The hood opens into an extraction duct (8) and, at its front side, has a window (9) which can be moved up and down. The upper bars (3) are hollow and each upper bar located in the vicinity of the window has a number of holes (12) in its upper side. Air or gas is passed into the interior of the upper bars via a pipe (10), and the air or gas emerging from the holes (12) forms a protective air or gas curtain when the window is open. This design renders unnecessary any additional pipes for the supply of air or gas and, as a result, access to the duct is unhindered. <IMAGE> |
