Abstract: A refractometer has a housing (1), a measurement cell (8) arranged in the housing (1), and a lid unit (2). The lid unit has a base plate (3) with a cutout (7) allowing access to the measurement cell, and a lid (4) for covering the measurement cell. The lid is connected to the base plate by way of a hinge. The lid unit also has a lid insert (11, 17, 18, 28, 31, 35, 39) that is arranged replaceably in the lid. The lid unit (2) is detachably connected to the housing by means of a connecting element that is itself connected to the base plate.

Abstract: A refractometer has a housing (1), a measurement cell (8) arranged in the housing (1), and a lid unit (2). The lid unit has a base plate (3) with a cutout (7) allowing access to the measurement cell, and a lid (4) for covering the measurement cell. The lid is connected to the base plate by way of a hinge. The lid unit also has a lid insert (11, 17, 18, 28, 31, 35, 39) that is arranged replaceably in the lid. The lid unit (2) is detachably connected to the housing by means of a connecting element that is itself connected to the base plate.

Abstract: Extractor (21) has extraction vessel (24) to which reflux line (26) is molded in one piece. Valve (1) which can be opened to allow the extract to flow back from extraction vessel (24) into distillation vessel (22) is sealed into reflux line (26). Valve (1) can be triggered depending on the height of the solvent level in extraction vessel (24).

Abstract: A height adjustable stand for laboratory equipment, in particular for rotary evaporators, possesses a holder arrangement (6). The holder arrangement is able to be displaced vertically on a stand post (5). By way of a motor driven lifting arrangement (9, 11), the holder device (6) can be vertically raised or lowered. A coupling (12) is provided between the holder arrangement (6) and the lifting arrangement (9, 11) for the powered connection and its release.

Abstract: Yarn is clamped between two rotatably mounted brake plates. The lower brake plate lies on an annular housing portion and the upper brake plate is held and centered by a guide plate. Weighting discs lie on the guide plate and are secured by a pair of clamping projections. The guide plate is displaceable on a U-shaped loop member and is prevented from rotating thereon and is itself secured by pairs of clamping projections.

Abstract: A thread withdrawn from a bobbin is passed along a straight line through a plate brake. A base brake plate is driven by a drive extending outside the periphery of the base brake plate. A tensioning device removably attached to a top brake plate is connected therewith by a ball snap-type connection. It comprises a first compression spring with one end supported at a gripping sleeve and slideable along a pressing pin surrounded by this compression spring. The gripping sleeve is connected to a displaceable control plate extending parallel to the pressing pin. This control plate permits a simultaneous variation and adjustment of the pressure exerted by a number of such similar tensioning devices. A second compression spring surrounding the pressing pin is supported at a side of the gripping sleeve remote from the first compression spring and counteracts the first compression spring, so that the difference of the spring forces acts upon the top brake plate.

Abstract: In a housing, two rollers having substantially parallel axes are freely rotatably journaled and bound between them a clamping bite. The thread to be braked is drawn through the clamping bite and thereby drives the rollers. A first of the two rollers is stationarily mounted in the housing. The second roller comprises a cover made of a rubber-elastic material. This second roller is journaled in a pivotable forked lever which is under the action of an angle lever. The second roller can be pressed against the stationary first roller with an adjustable operating bias by means of the angle lever and a force accumulator constituted by a tension spring. Spring means of a rapid braking device constitute a compression spring supported by a braking rod which is axially displaceable between two end positions. The compression spring acts upon a spring bush carrying a nose member. In one of the two end positions of the braking rod the nose member extends with play beneath an arm of the angle lever.