| 摘要 |
An enclosed fume hood having an access window with a vertically sliding sash is provided with an additional horizontally movable sash which closes off only a fraction of the open window space and thus reduces the volume of air required to be drawn through the window in order to maintain the requisite air velocity while still permitting complete access to the interior of the hood. Provision is also made to permit the horizontally movable sash to be easily removed, when necessary, to permit insertion into the hood of apparatus wider than the residual open window space.
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