| 摘要 |
<p>In a reducing station with safety operation in the negative direction for metering energy flows in the form of gases, vapours or water, especially in thermal or industrial power stations, the operating path (BS) of a regulating valve (SV) is supplemented by at least one other safety path (S1, S2) fitted with means to move a first spindle section (4.1) bearing the choke unit (3) at one end to the closed position, depending on a triggering signal from a pressure monitor. A second spindle section (4.2), coupled to the other end of the first spindle section via pre-tensioned springs (15') and non-self-limiting, brakable safety spindle threaded sections (20a...24a; 20b...24b), has a spindle drive (ST) which usually transfers the axial thrust or pull to the first spindle section (4.1) via the stationary safety spindle threaded sections. On triggering, the second spindle section (4.2) forms an abutment for the movement of the first spindle section (4.1) with the choke unit (3) into the rated position (closed) which is permitted by the safety spindles (28a, 28b). Preference is given to at least twosafety paths (S1, S2), each with a non-self-limiting safety spindle drive (20a, 20b). Both may engage with a two-armed safety lever (20) in the manner of a rocket. The operation of the safety paths (S1, S2) may be checked.</p> |
