Transcript Tomislav Skračić, MA Undergraduate English Course for

Tomislav Skračić, MA
Undergraduate English
Course for
MARINE ENGINEERS
2nd Semester
Essential reading:
SPINČIĆ, A., An English Textbook For Marine
Engineers I., Pomorski fakultet, Rijeka 2008.
LUZER, J., SPINČIĆ, A., Gramatička vježbenica
engleskog jezika za pomorce, Pomorski
fakultet, Rijeka 2003.
BOILER AUXILIARIES
Part 1 – Boiler fuel oil supply system
KEY WORDS
tank suctions
- usisi na tankovima
transfer pump
- pumpa za pretakanje, "transferica"
suction strainer
- usisni pročistač
grits
- pijesak, kamenčići
discharge strainer - tlačni pročistač
at a graduated rate - stupnjevanom količinom / brzinom
distribution box valve
- ventil razvodne stanice
spontaneous combustion - samozapaljenje
BOILER AUXILIARIES
Part 1 – Boiler fuel oil supply system
The fuel oil supply system consists of:
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Pumps
Heaters
Filters
Strainers
Tanks
Piping with accessories
Control devices (pressure gauges, thermometers...)
BOILER AUXILIARIES
Part 1 – Boiler fuel oil supply system
The fuel is stored in the double bottom tanks and is
drawn off by the fuel oil transfer pump. The tank
sections are fitted with steam heating coils to render oil
less viscous during cold weather.
The transfer pump delivers the oil to the settling tank.
When the tank is full, the pump is stopped and any water
in the oil settles to the bottom of the tank and is drained
off.
From the settling tank, oil is delivered to the daily or
service tank. Any fuel oil system is provided with a pair
of tanks, so that one can be filled and allowed to settle
while the other is being used to supply the boilers.
BOILER AUXILIARIES
Part 1 – Boiler fuel oil supply system
The oil, drawn from the service tank by the oil-fuel
pressure pump is forced through the suction strainer or
filter for removing grits and foreign matter.
The oil is then discharged under pressure to a heater in
which it is heated by steam to a temperature suitable for
spraying and burning. Heating of oil reduces viscosity
and make it easier to pump and filter.
Having reached the required temperature, oil is made to
pass through the discharge strainer, of finer mesh than
the first, and from there it flows to the burners.
BOILER AUXILIARIES
Part 1 – Boiler fuel oil supply system
A recirculating connection is fitted in the system for
starting the heater from cold.
The oil temperature at the burners must be correct and
this is raised by shutting the distribution box valve and
opening the recirculating valve which returns oil to the
heater until the working temperature is reached.
Once the required temperature is obtained, the
recirculating connection is closed and the hot oil is
passed to the boiler furnace through the fuel oil burners.
BOILER AUXILIARIES
Part 1 – QUESTIONS
1.
2.
3.
4.
5.
6.
7.
8.
What conditions are required for the efficiency of boiler
operation?
What main components and accessories does the system
include for supplying fuel to the boiler?
Where is the fuel stored?
How is the fuel moved and where to?
What are tank suctions fitted with and what is their purpose?
Why is the fuel oil supply system provided with diplicate
tanks?
What is the system equipped with for starting from cold?
How is the optimum working temperature of fuel oil obtained in
the system?
Exercise – Translate into English
Strojar, koji je bio zadužen za otkrivanje uzroka nepravilnog
rada (malfunction), izvjestio je da je tlak zraka bio prenizak
da bi se motor uputio.
2. Čelo (crown) klipa je izloženo vrućim plinovima izgaranja, pa
se zato hladi vodom. Količina vode ne smije se smanjivati kod
manjih opterećenja i okretaja (at low loads and revolutions)
kako bi se izbjegla oštećenja zbog termičnih naprezanja
(thermal loads).
3. Na posljednjem remontu (overhaul) nije se obratilo dovoljno
pozornosti podešavanju zračnosti (clearance) ventila, stoga
se ispušni ventili ne otvaraju u pravilnom trenutku.
4. Kod motora srednjih i većih snaga svi elementi glave cilindra
postavljeni su u posebnom kućištu, tako da nije potrebno
demontirati (dismantle) glavu da bi se izvršio popravak
ispušnog i usisnog, sigurnosnog i uputnog ventila.
1.
Exercise – Translate into English
a) Temperatura strojarnice je bila odviše niska da bi se uputio
motor (start the engine), pa se moralo rashladnom vodom
zagrijati cilindre i glave motora.
b) Nakon montaže košuljice u blok cilindra, treba ponovo
kontrolirati provrt (bore) košuljice kako bi se izmjerilo
odstupanje (deviation) od nazivnih (nominal) dimenzija.
c) Da bi se smanjila toplinska naprezanja (thermal loads) i
zaštitila mehanička čvrstoća rebara (division bars) između
ispušnih kanala košuljice cilindra, rebra su hlađena vodom.
d) U cilindrima s radnim košuljicama (wet liners), koje su u
direktnom dodiru s rashladnom vodom, postoji opasnost
propuštanja (risk of leak) vode u karter. Da se to ne dogodi
(in order to prevent this), umeću se između cilindra i
košuljice gumeni brtveni prstenovi (sealing rings).
BOILER AUXILIARIES
Part 2 – Boiler burners and air circulation
KEY WORDS
pressure jet type fuel oil burner - tlačni gorionik
whirling motion
- vrtložno gibanje
burner tip
- vrh gorionika
oil supply
- dovod goriva
burner carrier
- nosač gorionika
swirl plate
- ploča za raspršivanje
orifice plate
- ploča s kanalićima (tlačnog gorionika)
vortex chamber
- vrtložna komora
cap nut
- stezna matica / matica kape tlačnog
gorionika
BOILER AUXILIARIES
Part 2 – Boiler burners and air circulation
KEY WORDS
burner barrel
- tijelo / cijev / valjak gorionika
boiler casing
- kućište kotla
locking screw handle
- kolo zapornog vijka
stack
- brodski dimnjak
induced draught (draft)
- umjetni propuh
uptake (n.)
- dimovod
faint (adj.)
- slab, blijed
spontaneous combustion - samozapaljenje
at a graduated rate - stupnjevanom količinom / brzinom
BOILER AUXILIARIES
Part 2 – Boiler burners and air circulation
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The objective of the burner is to break oil into fine
particles (spray) and provide a whirling motion as it
issues from the burner tips.
Inside the furnace, the oil spray is mixed with the
air.
There are two methods for supplying the air:
a) natural draught (draft)
b) mechanical draught (draft)
BOILER AUXILIARIES
Part 3 – Boiler feed water system
KEY WORDS
air ejector
- zračni ejektor, ejektor zraka
de-aerator
- otplinjač
closed-feed system - zatvoreni napojni sustav
condensate
- kondenzat
air-pump
- pumpa zraka
condensate extraction pump - kondenzatna pumpa
gland steam condenser - kondenzator pare koja iscuri iz brtvenice
drain tank
- drenažni / odljevni tank
bled steam from the turbine - ispuštena para / oduzeta iz
niskotlačne turbine
recover heat
- obnoviti / regenerirati toplinu
direct contact feed heater
- dodirni zagrijač napojne vode
exhaust steam
- potrošena para
BOILER AUXILIARIES
Part 3 – Boiler feed water system
KEY WORDS
surface heater
- površinski zagrijač
copper tube
- bakrena cijev
dissolved gases
- otopljeni plinovi
storage tank
- spremnik
economiser
- zagrijač napojne vode
atmospheric drain tank
- drenažni / odljevni tank pod
atmosferskim tlakom
high evaporation rate - visoka stopa / brzina isparavanja
counteract (v.)
- neutralizirati, spriječiti
scale
- kamenac
pitting
- rupičasta korozija
priming (of the water) - kipljenje, burno vrenje vode
foaming (of the water)- pjenjenje vode
BOILER AUXILIARIES
Part 3 – Boiler feed water system
The feed water system consists of:
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Condenser
Air ejector
De-aerator
Boiler feed pumps
Feed water heaters
Other pumps
Tanks with piping
Valves
BOILER AUXILIARIES
Part 3 – Boiler feed water system
The feed water system consists of a condenser, an air
ejector, a de-aerator, boiler feed pumps, feed water
heaters, other pumps, tanks with piping and valves.
This is a closed-feed system for a high pressure
watertube boiler.
The closed-feed system prevents the re-entry of air into
the de-aerated condensate when it is returned to the
boiler.
The condenser is a heat exchanger which removes the
latent heat from the exhaust steam.
BOILER AUXILIARIES
Part 3 – Boiler feed water system
In modern steam turbine installation, the air-pump,
formerly used to extract the condensed steam together
with any air liberated from steam, is replaced by an air
ejector and a condensate extraction pump. While the
extraction pump deals with the condensate, the air ejector
removes the air and vapour from the condenser.
In passing through the air ejector, the condensate is
heated and air is removed using steam operated ejectors.
The condensate is then circulated through a gland steam
condenser where it is further heated. In this heat
exchanger, the turbine gland steam is condensed and
drains to the atmospheric drain tank.
BOILER AUXILIARIES
Part 3 – Boiler feed water system
The condensate is now passed through a low pressure
heater which is supplied with bled steam from the
turbine. All these various heat exchangers improve the
plant efficiency by recovering heat, and the increased
feed water temperature assists in the de-aeration process.
The de-aerator can be a direct contact feed heater, i.e.
The feed water and the heating steam actually mix, or it
can be a surface heater. In this type the water is kept
separate from the heating system by pumping it through
copper tubes which are surrounded by steam.
BOILER AUXILIARIES
Part 3 – Boiler feed water system
In addition to heating, any dissolved gases, particularly
oxygen, are released from the feed water. The lower part
of the de-aerator is a storage tank which supplies feed
water to the main feed pumps, one of which will supply
the boiler’s requirement.
BOILER AUXILIARIES
Part 3 – Boiler feed water system
The feed water passes to a high-pressure feed heater and
then to the economiser and the boiler water drum. An
atmospheric drain tank and a feed tank are present in
the system to store surplus feed water and supply it
when required.
Feed water for the boilers should, if at all possible, be
pure distilled water more especially for high pressure
work at high evaporation rate.
The purity of the water must be carefully watched,
regularly tested, and the necessary chemical treatment
given to counteract udesirable impurities which may
cause scale, pitting, priming and foaming of the water.
BOILER AUXILIARIES
Parts 2 & 3 – QUESTIONS
1. What is the purpose of boiler burners?
2. Why is natural draught insufficient to provide efficient
3.
4.
5.
6.
7.
combustion?
What is a closed water-feed system?
What is the opposite of a closed system and why is it
termed so?
Where does steam come to the condenser from?
How is this steam called?
What is a ‘condensate’?
BOILER AUXILIARIES
Parts 2 & 3 – QUESTIONS
8. What is a modern steam plant provided with, in place
of the air pump?
9. What is the purpose of the extraction pumps and air
ejectors?
10. Why are an atmospheric drain tank and feed tank
fitted to the system?
11. Why are several heat exchangers present in the feed
system?
12. What difference is there between a direct contact
feed heater and a surface heater?
BOILER AUXILIARIES
Parts 2 & 3 – QUESTIONS
13. Why must air and other gases (oxygen in particular)
be removed from the feed water?
14. What water must be used for feeding high pressure
boilers?
15. What undesirable effects may impure feed water
cause?
16. How can the quality of the boiler be maintained?
Exercise 1 – Match the definitions with the terms:
air ejector (vacuum pump), atmospheric drain tank,
condensate extraction pump, condenser, de-aerator,
economiser, feed pump, low pressure heater, superheater
1
2
3
4
The vessel in which boiler feed water is heated
under pressure to remove dissolve air and vapors
to minimise boiler internal corrosion.
A device used to transfer heat from boiler exit
(exhaust) gases to feed water, to increase the
efficiency of the boiler plant.
The pump used to draw water from a condenser
which is under vacuum.
A bank of tubes in the exhaust gas path from the
boiler furnace through which the steam passes to
raise its temperature above saturation
temperature.
Exercise 1 – KEY
air ejector (vacuum pump), atmospheric drain tank,
condensate extraction pump, condenser, de-aerator,
economiser, feed pump, low pressure heater, superheater
1
2
3
4
The vessel in which boiler feed water is heated
under pressure to remove dissolve air and vapors
to minimise boiler internal corrosion.
A device used to transfer heat from boiler exit
(exhaust) gases to feed water, to increase the
efficiency of the boiler plant.
The pump used to draw water from a condenser
which is under vacuum.
A bank of tubes in the exhaust gas path from the
boiler furnace through which the steam passes to
raise its temperature above saturation
temperature.
de-aerator
economiser
condensate
extraction p.
superheater
Exercise 1 – Match the definitions with the terms:
air ejector (vacuum pump), atmospheric drain tank,
condensate extraction pump, condenser, de-aerator,
economiser, feed pump, low pressure heater, superheater
5
6
7
8
9
A device that draws out the air and vapours which
are released from the condensing steam in the
condenser.
A heat exchanger used to reduce the temperature
of the water drains before entering the feed tank.
The pump that raises the feedwater to a pressure
high enough to enter the boiler.
The tank at atmospheric pressure to which
condensed water from auxiliaries, heating coils
etc. is led.
A chamber in which exhaust steam is led to
change back into water.
Exercise 1 – KEY
air ejector (vacuum pump), atmospheric drain tank,
condensate extraction pump, condenser, de-aerator,
economiser, feed pump, low pressure heater, superheater
5
6
7
8
9
A device that draws out the air and vapours which
are released from the condensing steam in the
condenser.
A heat exchanger used to reduce the temperature
of the water drains before entering the feed tank.
The pump that raises the feedwater to a pressure
high enough to enter the boiler.
The tank at atmospheric pressure to which
condensed water from auxiliaries, heating coils
etc. is led.
A chamber in which exhaust steam is led to
change back into water.
air ejector
(vacuum
pump)
low pressure
heater
feed pump
atmospheric
drain tank
condenser