A device (30) for feeding working fluid to an assembly (14) requiring working fluid includes at least one fluid channel (20, 20a-20d) extending from a surface (16a) and at least one screw element (22, 24) capable of being screwed from the surface (16a) into the at least one fluid channel (20, 20a-20d) for feeding working fluid into the fluid channel (20, 20a-20d) or for closing the fluid channel (20, 20a-20d), the at least one fluid channel (20, 20a-20d) having a first section (32) directly adjacent to the surface (16a) with a larger width, a second section (36) with a smaller width and, between the first section (32) and the second section (36), having a first transition region (34) with an annular surface (34a), and the screw element (22, 24) having at least one sealing surface (22c, 24c) capable of being brought into sealing engagement with the annular surface (34a). The fluid channel (20, 20a-20d) is deformable in the second section (36) by a pressure applied by the screw element (22, 24) to the annular surface (34a) in the sense of reducing the volume of the fluid channel in the second section (36).