Issues with the starting oil for the turbine quick-shut valve
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The turbine quick-shut valve is equipped with supply oil, quick-shut oil, and return oil pipelines. I would like to ask: through which pipeline does the supply oil return? Can it be returned through the supply oil pipeline as well?
This post was last edited by CHANGBAISHI on 2019-10-31 at 18:28 to clarify the process and see if it is related to the control system in the fuel system. First, create a flow diagram of the turbine quick-shut valve oil system; once that’s done, it will become clear. https://bbs.hcbbs.com/thread-1106255-1-1.html Posts from this forum; information on pages 3 and 4.
Yes, the starting oil can also return to the oil tank. The quick-shut valve is the main closing mechanism in steam pipelines and turbines. During low-speed warming up, it controls the amount of steam entering the turbine by adjusting its opening size, thereby regulating the speed. In the event of an accident during operation, it can cut off the steam supply to the turbine in the shortest possible time. The starting oil is directed to the right end of the piston; under the pressure of this oil, the piston is forced against the piston disk, causing its sealing surface to make contact with that of the piston disk. Afterwards, rapid-shut-off oil is introduced on the left side of the piston disk. As pressure from the rapid-shut-off oil builds up behind the piston disk, the starting oil begins to be released in a controlled manner. Thus, the piston disk and the piston act as a single unit, moving continuously to the right under the effect of the pressure difference between the two sides, until they are stopped by the piston on the right side. Since the left end of the valve stem is connected to the piston disc, as the piston disc moves, the quick-close valve also opens accordingly.
The starting oil must definitely be drained, and in order to prevent the quick-close valve from operating too quickly, the amount of starting oil that can be drained is limited
The start-up oil circuit serves both as an inlet and a return path; once the quick-shut valve is opened, the start-up oil remains in the return state
After the starting oil is established, the quick-shut oil can flow in; once the quick-shut oil is present, the starting oil is allowed to drain back slowly through the throttle orifice, thereby causing the quick-shut valve to open gradually.