Boiler Inteview Tip Flashcards
How to test ignition failure & flame failure
When we are testing for flame failure, before we fire the burner, WE NEED TO REMOVE THE FLAME EYE THEN FIRE THE BURNER, there you will get an ignition failure. While the flame failure test WE NEED TO FIRE THE BURNER THEN REMOVE THE FLAME EYE.
What is the purpose of a superheater?
To add heat to the steam without raising the pressure of the steam.
What is a superheater? Describe a typical desuperheater?
A desuperheater is a device for removing the superheat from steam. It usually consists of a coil of piping located in the steam drum of a boiler below the normal steaming water level. A connection is made from the outlet of the superheater to one end of the piping, and the other end of the piping is connected to a line leading to those auxiliaries which cannot use superheated steam. In passing through the desuperheater, the steam gives up its superheat to the water in the drum and emerges as saturated or mildly superheated steam.
What is the principal precaution in the operation of blow-down valves?
Do not leave blow-down valve until shut off.
Why are by-pass lines Installed around large steam-stop valves?
Steam-stop valves over 6” in diameter are required to have by- pass lines installed around them in order to warm up the line before opening the stop valve.
Where is the air cock located and what is its purpose?
The air cock is a small valve located at the very top of the steam space of a boiler. Its purpose is to allow air to escape from the boiler while raising steam or filling the boiler with water, and to allow air to enter the boiler while it is being drained.
When and how would you use the bottom blow?
The best time to use the bottom blow to remove solid matter from the boiler is when the boiler is cut out, as most of the heavy matter in the water will have had a chance to settle to the bottom of the boiler and a larger amount of it can be removed by blowing. It is better to give several short blows than one long blow, as more of the solid matter will be removed in that way. If reducing the salinity of the boiler water is the object, the boiler should be filled until the gage glass shows about 3/4 full; the bottom blow is then opened and kept open until the gage glass shows the water level to be just above the bottom nut on the gage- glass connection. This is repeated until the salinity, as indicated by samples taken from the boiler through the salinometer cock, is at the desired point.
How would you cut a boiler out of service?
- Close oil valves and air registers in each burner unit. (Reduce oil pressure)
- Secure master oil shut-off valve to boiler.
- Slow down blower.
- Secure steam stops.
- Secure feed lines.
- Remove all burners from boiler, remove tips, and place in kerosene.
- Open air vent when pressure drops to about 5 lbs. (Prevents formation of vacuum.)
What would you check if your fires went out in the boiler?
- See that the fuel-oil pump is operating.
- Fuel may not be hot enough for combustion.
- Fuel may be too cold to pump.
- Check pump and burner strainers.
- Bunker tank may be empty.
- Test for water in the fuel.
- Valve in the line may be closed by mistake.
- Vent screen in bunker tank may be clogged with dried fuel from a previous overflow, causing a vacuum in the tank.
Should the stress on a stop valve be relieved before steaming the boiler? Explain.
Yes. Break valve from seat to prevent valve from freezing when steam expands it.
What is the position of the feed-stop and check valves when the boiler is steaming? When the boiler is cut out?
When the boiler is steaming, the feed-stop valve is wide open and the feed-check valve is open only sufficiently to maintain the level of the water in the boiler. When the boiler is cut out, both stop and check valves are closed to prevent any water from entering the boiler.
If the water becomes dangerously low in a Scotch boiler, what would you do?
If the water in a Scotch boiler became dangerously low, the fusible plug would melt out. When this happens, secure the fires and feedwater at once; then secure the main and auxiliary steam stops and open the safety valve with the hand-lifting gear; secure the air to the furnaces and allow the boller to cool gradually. (Call chief engineer.) When the boiler has cooled, carefully ex- amine the crown sheets and upper rows of tubes for sag or any other sign of overheating. If no damage is found, renew the fusi- ble plugs and get up steam again. A report must be submitted to the inspectors in the next port where there is an Inspector. If damage was done by overheating, the inspector must first approve any necessary repairs.
How to Start Manually The MIURA marine aux gk series boiler?
During Manual Operation the ff alarms are disabled.
- Low Oil Pressure Alarm
- High Oil Temperature Alarm
- Low Oil Temperature Alarm
- Abnormal Fire Alarm
Step 1: From off position, operate the selector knob to Fan Running (Forced draft Fan will supply fresh air to remove the explosive fumes.)
(Fan Running: this will start the pre-purging of the combustion chamber for 35 seconds but we can extend it because it is manually operated)
-Wait for the sufficient prepurge lap to light up. This confirm that the pre purging is complete.
Step 2: Turn the selector knob to IGNITION. This will ignite the atomized fuel and air mixture inside the combustion chamber.
(Ignition Control: ignition sparks and the pilot burner also ignites)
-Wait for the combustion lamp to light up before proceeding to next step. (Aside from combustion lamp lighting up, confirm through the sight glass if the pilot burner is burning)
Step 3: After ignition, rotate the selector knob to PRI Combustion.
This allows the pilot burner and the main burner to fire simultaneously. (Check thru sight glass again if they are burning. Indication is the fire is brighter if the main burner is in operation.)
Step 4: Then select the COMB. for the final step. (COMB: makes the pilot burner stops and allows the main burner only to operate)
How to Start Automatically The MIURA marine aux gk series boiler
Just select the AUTO COMB thru the selector knob. Then press the combustion switch to start the operation.
