Siemens Aktiengesellschaft

Goeran Skog

Kenth A Nilsson

Sven-Gunnar Olsson

Goeran Rydgren

Goeran Cewers

Dan Linden

Mats Iderup

Bengt Jofs

Bo Dahlstroem

An apparatus, such as a ventilator, for regulating the flow-through amount of a flowing medium, such as a gas, has a valve with a variable orifice operated by a first regulating circuit with negative feedback. The regulating variable generated by the first regulating circuit controls the size of the orifice so that the difference between a desired value and an actual value for the flow-through amount os minimized, toward zero. To achieve rapid changes in the flow-through amount with a high regulating precision, at least one further regulating circuit is provided to which the regulating variable of the first regulating circuit is supplied as the desired value. The actual value for the further regulating circuit may be the measured position of the closure element for the orifice. The bandwidth and the gain can be optimized for each regulating circuit. The energy consumption can be lowered by current recovery and battery operation can be simplified, in the event of a power outage.

Apparatus for regulating the flow-through amount of a flowing medium

Matrix printer means having plurality of write heads. In order to be able to achieve a print width in matrix printer means that is greater than that of an individual write head and in order to simultaneously enhance the resolution beyond the basic resolution of the write head or in order to enable multi-color printing, a plurality of rows of write heads are provided. The neighboring write heads in one row and the rows themselves are arranged phase-shifted relative to one another or the colors of the write heads in every row and between the rows are cyclically interchanged. The plurality of required rows of write heads is thus reduced to a minimum.

Matrix printer means

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Stockholm, Sweden

Goeran Skog