Abstract: An air filtering device and a method of producing the device. The device is constructed from a number of modules of a first module type (4) and a second module type (6), which are arranged in series in a row. A module of the first module type (4) is arranged as an inlet module (4) with inlets (42), which is connected in series to modules (8, 10: 16) of the second module type (6). One of the latter may include a fan element (18) or one or more filter elements (12, 14), and one of them is arranged as an outlet module (16) and others as through-flow modules (8, 10). The modules are joined together by locking members (32) arranged in each module, in such a way that the modules create an enclosed air duct (4, 8, 10, 16).

Abstract: A telescopic extraction arm (1), having an outer tube (4) and an inner tube (6) displaceably and rotatably fitted therein. Via balancing rings (14, 16) fixed on each tube respectively, which are kept a pre-determinable distance apart by a stop member (18) arranged in the outer tube (4), the tubes can be easily displaced and locked in relation to one another with a negligible degree of the “drawer effect” occurring in conventional telescopic arrangements.

Abstract: The invention relates to a telescopic extraction arm (1), which has an outer tube (4) and an inner tube (6) displaceably and rotatably fitted therein. By means of balancing rings (14, 16) fixed on each tube respectively, which are kept a pre-determinable distance apart by a stop member (18) arranged in the outer tube (4), the tubes can be easily displaced and locked in relation to one another with a negligible degree of the “drawer effect” occurring in conventional telescopic arrangements.