Are the static blades of the catalytic axial-flow main fan operating?
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The main air flow regulator of the catalytic axial-flow main fan is controlled manually via DCS; a bypass is activated in case of an extremely low pressure of the power oil in the unit. If both power oil pumps fail and stop operating, resulting in a shortage of power oil, will the stator vanes of the main fan move (close)?
Such a great post like this shouldn’t sink to the bottom of the sea
Similarly, such a great post like this shouldn’t sink to the bottom
What type of actuator is used for the main fan guide vanes? Do the guide vanes have actuators?
The static blades are closed to the minimum, and the unit operates in a safe manner.
Although ours is not of the axial flow type, I think the equipment should be designed to account for extreme situations – it’s essential that the stationary blades return to the minimum safe angle!
In the interlock logic, low oil pressure triggers a shutdown interlock; at this point, the remaining pressure of the power oil can be used to close the stator vanes. There is a pressure regulator.
The self-protection system must be designed with this feature; otherwise, it will cause significant damage to the equipment. We have such a system here.
After the oil pump stops operating, the stator blades need to return to their stopped position; this is a mechanical action that occurs regardless of what happens in the control circuitry. Imagine if, after the oil pump stops, the stator blades do not move as a result of the interlock mechanism – with today’s strong emphasis on energy conservation, the oil pump would have been turned off long ago
Our system features a power oil supply system of type DYZ33-16, which provides 12 MPa of pressure oil to the servo motor of the adjustable stator actuator for axial flow fans (with the motor piston having a total travel distance of 80 mm). In this context, does the number 33 indicate the volume of power oil outputted in liters per minute, and does the number 16 refer to the nominal volume of the accumulators (in liters, with two accumulators in total)? You have now switched to BDY-B, which is an electro-hydraulic actuator produced by Jiujiang Instrument Factory. How is its performance? Is the adjustment of the stator vanes sensitive?
The stator blades can’t be purely mechanical in operation, right? It should be driven by power oil at 12 MPa to operate the servo motor and adjust the blade angle. If both power oil pumps fail, and it is necessary to adjust the blade angle or if an emergency occurs requiring the unit to operate in safe mode or shut down urgently, the two accumulators in the power oil system can ensure that the blades return to their starting angle. Just as the backup accumulators in electrical slide valves allow for manual operation in case of a power outage to the pump motors or a failure of the hydraulic pumps.