| abstract |
The valve (110) includes a valve stem (111) coaxially slidable in the valve body (112), the valve body (112) (110) and the valve stem (111) defining an annular metering chamber (113), the outer a seal (117) and an inner seal (118) between the outer and inner ends of the valve body (112) (110) and the valve stem (111) (110) for closing the annular chamber (113). At least a portion of the inner surface of the metering valve (110) has a layer of at least one cold plasma polymerized monomer bonded to the surface, the inner surface being the surface (112) of the valve (110). The layer consists of a cold plasma polymerized fluorocarbon and the layer is a cold plasma polymerized perfluorohexane, perfluorocyclohexane, tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, fluoroethylene or fluoropropylene. |