Question 470Steam Plants - Assistant Engineer70% to pass
Which of the listed sequence of events occurs when an automatic auxiliary boiler is prepurged?
AI Explanation
The correct answer is B.
When an automatic auxiliary boiler is prepurged, the damper on the inlet side of the furnace is moved to the open position for a given number of seconds to allow for the removal of any unburnt fuel or gases from the furnace prior to ignition. This is done to ensure a safe and complete combustion process. The damper is then moved to the low fire position to prepare the boiler for ignition at a reduced firing rate.
The other options are incorrect because they do not accurately describe the sequence of events that occurs during the prepurge of an automatic auxiliary boiler. Option A describes the damper being moved to the closed position, which would not allow for the necessary air flow and purging of the furnace. Options C and D describe actions that are not specific to the prepurge process for an automatic auxiliary boiler.
Related Questions
#468 If it is necessary to operate a turbine driven main feed pump at shut off head, or at less than 20% of its rated capacity, what will prevent the pump from overheating? #469 Which of the following actions takes place in the control circuit of an automatically fired auxiliary boiler when the desired steam pressure is obtained? #471 A photoelectric cell installed in an automatically fired auxiliary boiler burner management system _______________.#472 The pressuretrol which is installed on an auxiliary boiler senses steam pressure changes and _______________.#473 The primary function of a flame safeguard system, as used on an automatically fired auxiliary boiler, is to prevent _______________.