Abstract: In a switched-mode regulator for operation of an electromagnet having a magnet coil using different supply voltages the operating voltage UB of the electromagnet is produced by means of a storage circuit including a storage choke (2). To achieve cost and space-saving operation of the electromagnet using different supply voltages UV, the storage choke also acts as the magnet coil of the electromagnet.

Abstract: A multi-part fluid filter housing having first and second parts and being arranged to contain a replaceable filter element includes complementary frusto-conical mating surfaces between the two parts. The two parts are held together by a screw threaded ring which is screwed onto the outer face of the first part and which includes an internal flange engaging an external flange on the second part. The second part is tapered to improve the flow characteristics of the housing and preferably includes a taper of between 1 and 2%.

Abstract: A filter element for filtering air, other gases and liquids comprises two permeable supporting shells arranged one within the other, and a filter medium filling the space between the shells. The filter medium is formed by a plurality of layers of different filter gauge. The finest filter layer is covered by a coarser filter layer at least on its side which is, in use, towards the inlet for the fluid to be filtered. Preferably the filter medium includes three layers, the middle layer of which is the finest filter consisting of binder-free microfiber fleece and the other two layers are similar coarser filters consisting of binder-free supporting fiber fleece.