| 摘要 |
A multi-stage pressure regulating system including a pilot-governed main pressure reducing regulator, with one or more passive back pressure regulators arranged in tandem therewith. The regulators are valves of the type conditioned to open when the upstream pressure therein overcomes a jacket pressure. The jacket in the main valve is loaded by upstream fluid, but a pilot, which monitors a particular fluid flow characteristic, such as pressure, at a selected location in the pipeline, controls bleeding of the jacket as necessary to regulate flow through the main valve so as to maintain a predetermined value or level of the characteristic being monitored. Hence, flow through the main valve is controlled solely by the pilot device, but its discharge to the ultimate downstream level is through at least one auxiliary valve, the jacket of which is loaded with a pneumatic pressure at a suitable level, so that the pressure drop to the downstream level is in two or more stages. |
