Abstract: In a thermally sprayed, gastight protective layer for metal substrates, such as Fe, Ni, Al, Mg and/or Ti, the spray powder for the purpose includes at least two components. The first is a silicate mineral or rock and the second is a metal powder and/or a further silicate mineral or rock. The silicate mineral or rock component in the spray powder has an alkali content of less than 6 percent by weight.

Abstract: A valve rotating mechanism for exhaust valves, especially of marine diesel engines, which mechanism is braced in a valve housing for the valve stem (1) between an upper and a lower drive element, is linked to the lower drive element via a freewheel device, which transmits rotation of the valve stem (1) during closing movement thereof, and is also braced relative to the upper drive element via a rotary cylinder (15), which brings about rotation of the valve stem (1) through engagement with a fixed support cylinder (13). Therein the rotary cylinder (15) and support cylinder (13) are engaged with one another via a helical gearing, wherein the rotary cylinder (15) is linked to the valve stem (1) via the freewheel device and the support cylinder (13) is fastened on the housing side.