Side of boiler.
The right hand side of the boiler showing the pressure gauge,access ladder and the circulating pipe inlet.
Sunday, January 25, 2009
Questions Relating to Boiler Operation. A good test for boiler operators
Give a short description on how to prepare a fire.
When starting your boiler where should your dampers be?
Having lit the fires, give a short summary of how to get your fires to burn properly.
What is the function of the Mobrey`s.(a) Describe what the single Mobrey does and (b) describe what the dual Mobrey does, (c) How often should the Mobrey`s be tested and why?
Describe how to blow down the gauge glasses, and explain why the gauge glasses must be blown down and how often.
Explain how to test the safety valves and explain why they should be tested and how often.
When steaming how often must the boiler be blown down and why?
In case of a power failure what steps should be taken and in which order?
In the following emergencies, describe what should be done?
(a) Low water
(b) High water
(c) Live coals falling off rear of stoker
(d) Safety valves lifting
(e) Pump tripping out
(f) Stoker jamming
(g) I D fan tripping
(h) Alarm sounding.
When raising steam from cold how long must be taken and what procedures should be followed?
When putting the boiler on range describe what must be done and why?
Why should the Main steam stop valve/Crown valve not be opened too quickly, and what can happen if it is opened too fast?
When steam demand decreases how do you control your boiler?
When the demand increases what must be done to maintain pressure?
Who is allowed to make adjustments to the boiler?
How often should the boiler be de-ashed?
How often should your fires be checked?
How do you bank a fire?
How do you un-bank a fire?
Why is it important to maintain a ballanced draft?
Where can you check to see if your fires are burning properly?
By looking at your fires how can you tell if they are burning properly?
What is a short fire and what is a long fire?
Whatdistance from the end of the grate should your fires be dead?
What is a balanced draft?
How many turns of the stoker indicator disc does it take to advance the stoker one link?
Where is the air release valve?
At what pressure should the air release valve be closed when raising steam?
When raising steam why should the air release valve be open?
What is the maximum pressure at which the boiler may be operated?
Give a short description on how to prepare a fire.
When starting your boiler where should your dampers be?
Having lit the fires, give a short summary of how to get your fires to burn properly.
What is the function of the Mobrey`s.(a) Describe what the single Mobrey does and (b) describe what the dual Mobrey does, (c) How often should the Mobrey`s be tested and why?
Describe how to blow down the gauge glasses, and explain why the gauge glasses must be blown down and how often.
Explain how to test the safety valves and explain why they should be tested and how often.
When steaming how often must the boiler be blown down and why?
In case of a power failure what steps should be taken and in which order?
In the following emergencies, describe what should be done?
(a) Low water
(b) High water
(c) Live coals falling off rear of stoker
(d) Safety valves lifting
(e) Pump tripping out
(f) Stoker jamming
(g) I D fan tripping
(h) Alarm sounding.
When raising steam from cold how long must be taken and what procedures should be followed?
When putting the boiler on range describe what must be done and why?
Why should the Main steam stop valve/Crown valve not be opened too quickly, and what can happen if it is opened too fast?
When steam demand decreases how do you control your boiler?
When the demand increases what must be done to maintain pressure?
Who is allowed to make adjustments to the boiler?
How often should the boiler be de-ashed?
How often should your fires be checked?
How do you bank a fire?
How do you un-bank a fire?
Why is it important to maintain a ballanced draft?
Where can you check to see if your fires are burning properly?
By looking at your fires how can you tell if they are burning properly?
What is a short fire and what is a long fire?
Whatdistance from the end of the grate should your fires be dead?
What is a balanced draft?
How many turns of the stoker indicator disc does it take to advance the stoker one link?
Where is the air release valve?
At what pressure should the air release valve be closed when raising steam?
When raising steam why should the air release valve be open?
What is the maximum pressure at which the boiler may be operated?
Expansion Bellows.
From the photo`s you can see examples of a correctly fitted bellows and a bellows which is incorrectly fitted. It is obvious from the incorrectly fitted bellows that no allowance was provided for the expansion of the steam line, whereas with the other bellows enough allowance was made for the expansion. Remember when fitting the bellows, a steam line expands at approximately 2mm for every meter of piping. Sufficient anchor points should be provided so that the piping does not push the building or any brackets on which it is resting. The steam piping must be able to move on its supports either by means of hanging brackets or on rollers or as illustrated with slide brackets which allows the piping to expand along its length while preventing it from moving either up or towards the side.
From the photo`s you can see examples of a correctly fitted bellows and a bellows which is incorrectly fitted. It is obvious from the incorrectly fitted bellows that no allowance was provided for the expansion of the steam line, whereas with the other bellows enough allowance was made for the expansion. Remember when fitting the bellows, a steam line expands at approximately 2mm for every meter of piping. Sufficient anchor points should be provided so that the piping does not push the building or any brackets on which it is resting. The steam piping must be able to move on its supports either by means of hanging brackets or on rollers or as illustrated with slide brackets which allows the piping to expand along its length while preventing it from moving either up or towards the side.
Saturday, January 17, 2009
Boiler Pressure Gauge.
The boiler pressure gauge must have a Red line indicating the maximum working pressure, the line must be on the gauge face and not on the protective glass.
The pressure gauge must also have a siphon tube ( some times also called a pig`s tail ) between the boiler and the pressure gauge.
This Siphon tube fills up with water when the boiler is in operation, which prevents the hot steam from reaching the pressure gauge and possibly causing damage to the gauge.
The Gauge should also be properly calibrated by a competent company, who will issue a certificate for the gauge.
The boiler pressure gauge must have a Red line indicating the maximum working pressure, the line must be on the gauge face and not on the protective glass.
The pressure gauge must also have a siphon tube ( some times also called a pig`s tail ) between the boiler and the pressure gauge.
This Siphon tube fills up with water when the boiler is in operation, which prevents the hot steam from reaching the pressure gauge and possibly causing damage to the gauge.
The Gauge should also be properly calibrated by a competent company, who will issue a certificate for the gauge.
Boiler Feed Pumps.
On a coal fired boiler at least two (2 ) feed pumps are required.
Should one feed pump fail, there is a stand-by pump available to ensure a continuous supply of water.
Your stand-by pump should be tested at least once a day/shift or preferably the feed pumps should be rotated on a regularly basis, with each pump being put into service on a weekly basis.
Should a pump fail it must be either replaced or repaired immediately, in case the other pump should also fail. Should both pumps fail for any reason, your fires must be dumped immediately and the Main steam stop valve ( Crown Valve ) closed, to save any water remaining in the boiler.
The feed pumps should of course always be kept in peak condition.
The boiler feed pumps must deliver a pressure of at least one and a half times the boiler pressure, that is with a boiler pressure of 1000Kpa the feed pumps should deliver at least 1500Kpa.
On a coal fired boiler at least two (2 ) feed pumps are required.
Should one feed pump fail, there is a stand-by pump available to ensure a continuous supply of water.
Your stand-by pump should be tested at least once a day/shift or preferably the feed pumps should be rotated on a regularly basis, with each pump being put into service on a weekly basis.
Should a pump fail it must be either replaced or repaired immediately, in case the other pump should also fail. Should both pumps fail for any reason, your fires must be dumped immediately and the Main steam stop valve ( Crown Valve ) closed, to save any water remaining in the boiler.
The feed pumps should of course always be kept in peak condition.
The boiler feed pumps must deliver a pressure of at least one and a half times the boiler pressure, that is with a boiler pressure of 1000Kpa the feed pumps should deliver at least 1500Kpa.
Opening Valves.
The correct way to open a valve is to do so slowly, once the valve is fully open turn the handwheel back approximately a ¼ ( quarter ) turn..
This is done so that when the time comes to operate the valve again, strain is not applied to the valve, as it is then easy to see which way the valve handle should turn
The correct way to open a valve is to do so slowly, once the valve is fully open turn the handwheel back approximately a ¼ ( quarter ) turn..
This is done so that when the time comes to operate the valve again, strain is not applied to the valve, as it is then easy to see which way the valve handle should turn
Gauge Glasses.
Please take note of the red and white chevrons behind the Gauge glasses, in the photograph.These chevron plates are positioned behind the glasses to assist in making the water in the glass tube more visible, by refraction.
To explain, where the level of the water is in the glass the angle of the red and white stripes change, which makes it easier to see the level of the water.
Gauge glasses do not generally come out ready fitted with chevrons, but they are easy enough to make and fit.
The Gauge glasses should be illuminated to make them more visible.
Please take note of the red and white chevrons behind the Gauge glasses, in the photograph.These chevron plates are positioned behind the glasses to assist in making the water in the glass tube more visible, by refraction.
To explain, where the level of the water is in the glass the angle of the red and white stripes change, which makes it easier to see the level of the water.
Gauge glasses do not generally come out ready fitted with chevrons, but they are easy enough to make and fit.
The Gauge glasses should be illuminated to make them more visible.
Safety Valves.
From the photo`s the quick release handles are clearly visible.
Photo`s are of a double beat valve and a single safety valve.Each safety valve must be able to handle the full load of the boiler.In other words when the boiler is producing at maximum output each safety valve must be able to keep the boiler at the valves set blow off point without the boiler increasing in pressure.
From the photo`s the quick release handles are clearly visible.
Photo`s are of a double beat valve and a single safety valve.Each safety valve must be able to handle the full load of the boiler.In other words when the boiler is producing at maximum output each safety valve must be able to keep the boiler at the valves set blow off point without the boiler increasing in pressure.
Friday, January 2, 2009
Discharging of Live Coals.
There are a number of reasons why a boiler discharges live coals off the end of the stoker grate. They are usually because the coal bed is too thick and the fuel trim is set too high, with the result that the stoker is running too fast. To remedy this decrease the thickness of the coal bed or set your fuel trim down, to slow the stoker. Remember the thicker the coal bed the slower your stoker must run, conversly the thinner your coal bed the faster your stoker must run.
It could also be caused by the demand for steam being suddenly reduced, with the dampers having to be closed causing live coals to be discharged and the boiler to discharge black smoke from the stack, before you have had time to adjust the boiler settings.
The undergrate dampers could also be closed,causing your fires to be incompletely combusted. To remedy this open your undergrate dampers.
Another reason for discharging live coals could be caused by the boiler tubes being blocked, in this case, the boiler must be stopped and the boiler tubes cleaned.
To find out if your boiler tubes are blocked, a good indicator is when your I. D damper is fully open while the F.D dampers remain closed. Your draft gauges will however indicate a balanced draft.
There are a number of reasons why a boiler discharges live coals off the end of the stoker grate. They are usually because the coal bed is too thick and the fuel trim is set too high, with the result that the stoker is running too fast. To remedy this decrease the thickness of the coal bed or set your fuel trim down, to slow the stoker. Remember the thicker the coal bed the slower your stoker must run, conversly the thinner your coal bed the faster your stoker must run.
It could also be caused by the demand for steam being suddenly reduced, with the dampers having to be closed causing live coals to be discharged and the boiler to discharge black smoke from the stack, before you have had time to adjust the boiler settings.
The undergrate dampers could also be closed,causing your fires to be incompletely combusted. To remedy this open your undergrate dampers.
Another reason for discharging live coals could be caused by the boiler tubes being blocked, in this case, the boiler must be stopped and the boiler tubes cleaned.
To find out if your boiler tubes are blocked, a good indicator is when your I. D damper is fully open while the F.D dampers remain closed. Your draft gauges will however indicate a balanced draft.
Truimph Chaingrate Stokers
Truimph Chain Grate Stokers.
Truimph chain grate stokers use the Carter Hydraulic gearboxes to drive the chain. Occasionly the gear boxes will run out of oil,due to leaks caused by `O` Rings that have perished,got hard or are broken. When this happens, the stoker will run intermittently, (Stop/Start).
To rectify, these gearboxes must be filled with oil.
The oilfiller is located on the side of the gearbox and the filler nut can be removed using a 24mm Ring spanner, once the nut has been removed pour the appropiate oil into the gear box until it just starts coming out of the filler hole. The nut must now be replaced and tightened.The stoker should now run continuosly again.
Truimph chain grate stokers use the Carter Hydraulic gearboxes to drive the chain. Occasionly the gear boxes will run out of oil,due to leaks caused by `O` Rings that have perished,got hard or are broken. When this happens, the stoker will run intermittently, (Stop/Start).
To rectify, these gearboxes must be filled with oil.
The oilfiller is located on the side of the gearbox and the filler nut can be removed using a 24mm Ring spanner, once the nut has been removed pour the appropiate oil into the gear box until it just starts coming out of the filler hole. The nut must now be replaced and tightened.The stoker should now run continuosly again.
Wednesday, December 24, 2008
SCHEDULE OF BOILER DUTIES.
· Every half hour check boiler feed pumps and take pressure and temperature readings.
· Every five to ten minutes check the ash in the boiler and clean out if necessary ( Do not allow
ash to build up in the boiler as it will cause problems.)
· Ash must be placed in the ash yard after removal from the boiler and wetted down.
· The ash must be piled up into a heap and not be allowed to spread beyond the ash yard.
· The ash must be kept wet in the ash yard.
· Every five to ten minutes check the stoker speed and adjust if necessary.
· Every five to ten minutes check that the stokers are running smoothly and not jamming.
· Every hour sweep the boiler house floor and remove any loose items from the floor.
· The boiler must under no circumstances be left unattended.
· Every shift must make sure that the build up of ash and coal dust on the boiler is removed on a
regular basis.
· Every shift must make sure that the boiler panel is kept clean and tidy. ( No ash or coal dust must accumulate on the boiler panel.)
· The top of the boiler panel must be kept clean and tidy, free of any foreign objects.
· A regular check must be kept on the coal to make sure that there are no pieces of steel,pieces
of brick or stones in the coal,and removed from the coal if found
· The area around the boiler house must be kept clean and tidy, all rubbish to be removed.
· The coal yard must be kept clean and tidy. All rubbish to be removed.
· The coal must be kept wet, every hour water must be sprayed on the coal.
· No unauthorized person is allowed in the boiler house.
· No person is allowed to use the boiler house as a short cut.
· Any unauthorized person found in the boiler house will be disciplined.
· No unauthorized person to handle or make any adjustments on the boiler.
· Hot water will not be provided to any person under any circumstances.
· Before shift change, wash the boiler house floor with water and remove excess water.
· Before shift change, Make sure the boiler house is clean and tidy ready for the next shift.
· When removing ash from the boiler, the boiler will smoke from the front, this is
because the draft has been disturbed. Do not adjust the F D dampers until the
boiler has settled down again.
· Every five minutes check that your fires are still under the arch, especially after removing ash
from the boiler.
· Every half hour check boiler feed pumps and take pressure and temperature readings.
· Every five to ten minutes check the ash in the boiler and clean out if necessary ( Do not allow
ash to build up in the boiler as it will cause problems.)
· Ash must be placed in the ash yard after removal from the boiler and wetted down.
· The ash must be piled up into a heap and not be allowed to spread beyond the ash yard.
· The ash must be kept wet in the ash yard.
· Every five to ten minutes check the stoker speed and adjust if necessary.
· Every five to ten minutes check that the stokers are running smoothly and not jamming.
· Every hour sweep the boiler house floor and remove any loose items from the floor.
· The boiler must under no circumstances be left unattended.
· Every shift must make sure that the build up of ash and coal dust on the boiler is removed on a
regular basis.
· Every shift must make sure that the boiler panel is kept clean and tidy. ( No ash or coal dust must accumulate on the boiler panel.)
· The top of the boiler panel must be kept clean and tidy, free of any foreign objects.
· A regular check must be kept on the coal to make sure that there are no pieces of steel,pieces
of brick or stones in the coal,and removed from the coal if found
· The area around the boiler house must be kept clean and tidy, all rubbish to be removed.
· The coal yard must be kept clean and tidy. All rubbish to be removed.
· The coal must be kept wet, every hour water must be sprayed on the coal.
· No unauthorized person is allowed in the boiler house.
· No person is allowed to use the boiler house as a short cut.
· Any unauthorized person found in the boiler house will be disciplined.
· No unauthorized person to handle or make any adjustments on the boiler.
· Hot water will not be provided to any person under any circumstances.
· Before shift change, wash the boiler house floor with water and remove excess water.
· Before shift change, Make sure the boiler house is clean and tidy ready for the next shift.
· When removing ash from the boiler, the boiler will smoke from the front, this is
because the draft has been disturbed. Do not adjust the F D dampers until the
boiler has settled down again.
· Every five minutes check that your fires are still under the arch, especially after removing ash
from the boiler.
How to advance a fire using the Crank handle.
Truimph chaingrate stoker.
Should it be necessary to turn the stokers using the crank handle proceed as follows:-
Remove the shear pin from the stoker drive and fit the crank handle to the squared end on the stoker drive.
Proceed to turn the crank handle until the fire has moved away from the guillotine door.
Every five to ten minutes check that the fire has not burned back under the guillotine door; if the fire has burned back proceed to advance the fire away from the door.
Should the situation require that the stoker is idle for a long period it is advisable to either bank the boiler or to push the fires off the end of the grate/s using a long rake
Remember seven (7 ) complete turns of the crank handle advances the grate by one stoker link.
Truimph chaingrate stoker.
Should it be necessary to turn the stokers using the crank handle proceed as follows:-
Remove the shear pin from the stoker drive and fit the crank handle to the squared end on the stoker drive.
Proceed to turn the crank handle until the fire has moved away from the guillotine door.
Every five to ten minutes check that the fire has not burned back under the guillotine door; if the fire has burned back proceed to advance the fire away from the door.
Should the situation require that the stoker is idle for a long period it is advisable to either bank the boiler or to push the fires off the end of the grate/s using a long rake
Remember seven (7 ) complete turns of the crank handle advances the grate by one stoker link.
How to un-bank a Boiler
At the I D damper control, open the damper fully to create a slight draft in the combustion chamber.
Open the guillotine door to the 200mm mark on the indicator plate, rake open the fire and spread fresh coal over the live coals after opening and closing the coal cut off door, dropping fresh coal onto the front of the stoker. Spread the coal evenly over the width of the stoker making sure that the live coal / fire is under the ignition arch and just behind the guillotine door.
Close the guillotine door to 100 to 120mm above the grate and open the coal cut off door.
At the I D fan control close the ID fan damper and make sure that the FD dampers are closed.
At the panel start the ID fan, then the FD fan/s keeping the stokers in the off position.
When you have ignition start the stokers and check that the fire does not move out from under the ignition arch, if necessary stop the stoker until ignition has been regained.
Once you are satisfied that you have ignition, start opening the dampers, starting with the ID damper and then the FD dampers to prevent a pressure build up in the combustion chamber, maintaining a balanced draft of -3pa on the draft gauge.
Remember to check the water level in the boiler and top up with water if necessary.
At the I D damper control, open the damper fully to create a slight draft in the combustion chamber.
Open the guillotine door to the 200mm mark on the indicator plate, rake open the fire and spread fresh coal over the live coals after opening and closing the coal cut off door, dropping fresh coal onto the front of the stoker. Spread the coal evenly over the width of the stoker making sure that the live coal / fire is under the ignition arch and just behind the guillotine door.
Close the guillotine door to 100 to 120mm above the grate and open the coal cut off door.
At the I D fan control close the ID fan damper and make sure that the FD dampers are closed.
At the panel start the ID fan, then the FD fan/s keeping the stokers in the off position.
When you have ignition start the stokers and check that the fire does not move out from under the ignition arch, if necessary stop the stoker until ignition has been regained.
Once you are satisfied that you have ignition, start opening the dampers, starting with the ID damper and then the FD dampers to prevent a pressure build up in the combustion chamber, maintaining a balanced draft of -3pa on the draft gauge.
Remember to check the water level in the boiler and top up with water if necessary.
How to bank a boiler.
At the panel, make sure that the boiler is on panel control.
Close the coal cut off door and open the guillotine door to 200mm.
Rake most of the coal off the front of the stoker with a rake, now push the rest of the coal into and onto the live coals in the combustion chamber,making sure that the live coal and the unburnt coal is well mixed with the live coal on top of the unburnt coal,also making sure that the coal is pushed back from the guillotine door for approximately 450mm.
Now close the guillotine door until the indicator plate reads approximately 20mm, now seal the gap between the guillotine door and the stoker with fresh coal to prevent air getting into the combustion chamber.
At the I D damper control, open the damper until you have a reading of -3pa at the draft gauge/ photohelix making sure that the FD dampers are closed.
Fill the boiler with water to the high water mark, making sure that the mainsteam stop valve is closed.
Make sure that the feed pumps are on Auto and that the feedwater valve is open and that the feed water tank is full, this will prevent the boiler running short of water as the boiler cools down
At the panel, make sure that the boiler is on panel control.
Close the coal cut off door and open the guillotine door to 200mm.
Rake most of the coal off the front of the stoker with a rake, now push the rest of the coal into and onto the live coals in the combustion chamber,making sure that the live coal and the unburnt coal is well mixed with the live coal on top of the unburnt coal,also making sure that the coal is pushed back from the guillotine door for approximately 450mm.
Now close the guillotine door until the indicator plate reads approximately 20mm, now seal the gap between the guillotine door and the stoker with fresh coal to prevent air getting into the combustion chamber.
At the I D damper control, open the damper until you have a reading of -3pa at the draft gauge/ photohelix making sure that the FD dampers are closed.
Fill the boiler with water to the high water mark, making sure that the mainsteam stop valve is closed.
Make sure that the feed pumps are on Auto and that the feedwater valve is open and that the feed water tank is full, this will prevent the boiler running short of water as the boiler cools down
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