| 摘要 |
A hood structure for air flow measurements on ceiling registers is erected on a fixed square bottom base with an adjustable curtained aperture and mounting for an air flow meter. A hood skirt is stretched by means of four struts that fit against the upper rim to which the skirt is attached (as well as to the base). The rim is made of rigid strips connected together in a ring by securable pivot joints, so that the open top of the hood can have square, round or various elongated shapes for better fitting to a ceiling register or orifice. This enables the use of a smaller bottom frame than would otherwise be necessary for measuring flow out of elongated narrow registers. All but two joints are preferably equipped with pivoted forked braces for securing the angular adjustment of hinged joints connecting angle-bar rim segments by clamping the forked end. The completely removable struts are flexible enough so that the rim may be brought fairly close to the base, by means of a twist, for passing the structure through a narrow doorway without removing the struts.
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