1. 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. Tomislav Skračić, MA Undergraduate English Course for MARINE ENGINEERS 2nd Semester

2. 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

3. The fuel oil supply system consists of: Pumps Heaters Filters Strainers Tanks Piping with accessories Control devices (pressure gauges, thermometers...) BOILER AUXILIARIES Part 1 – Boiler fuel oil supply system

4. 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

5. 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

6. 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 – Boiler fuel oil supply system

7. 1. What conditions are required for the efficiency of boiler operation? 2. What main components and accessories does the system include for supplying fuel to the boiler? 3. Where is the fuel stored? 4. How is the fuel moved and where to? 5. What are tank suctions fitted with and what is their purpose? 6. Why is the fuel oil supply system provided with diplicate tanks? 7. What is the system equipped with for starting from cold? 8. How is the optimum working temperature of fuel oil obtained in the system? BOILER AUXILIARIES Part 1 – QUESTIONS

8. 1. 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. Exercise – Translate into English

9. 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). Exercise – Translate into English

10. 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

11. 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

12. 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 2 – Boiler burners and air circulation

13. 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

14. 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

15. The feed water system consists of: 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

16. 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

17. 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

18. 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

19. 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 boilers requirement. BOILER AUXILIARIES Part 3 – Boiler feed water system

20. 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 Part 3 – Boiler feed water system

21. 1. What is the purpose of boiler burners? 2. Why is natural draught insufficient to provide efficient combustion? 3. What is a closed water-feed system? 4. What is the opposite of a closed system and why is it termed so? 5. Where does steam come to the condenser from? 6. How is this steam called? 7. What is a condensate? BOILER AUXILIARIES Parts 2 & 3 – QUESTIONS

22. 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

23. 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? BOILER AUXILIARIES Parts 2 & 3 – QUESTIONS

24. 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 1The vessel in which boiler feed water is heated under pressure to remove dissolve air and vapors to minimise boiler internal corrosion. 2A device used to transfer heat from boiler exit (exhaust) gases to feed water, to increase the efficiency of the boiler plant. 3The pump used to draw water from a condenser which is under vacuum. 4A bank of tubes in the exhaust gas path from the boiler furnace through which the steam passes to raise its temperature above saturation temperature.

25. Exercise 1 – KEY air ejector (vacuum pump), atmospheric drain tank, condensate extraction pump, condenser, de-aerator, economiser, feed pump, low pressure heater, superheater 1The vessel in which boiler feed water is heated under pressure to remove dissolve air and vapors to minimise boiler internal corrosion. de-aerator 2A device used to transfer heat from boiler exit (exhaust) gases to feed water, to increase the efficiency of the boiler plant. economiser 3The pump used to draw water from a condenser which is under vacuum. condensate extraction p. 4A bank of tubes in the exhaust gas path from the boiler furnace through which the steam passes to raise its temperature above saturation temperature. superheater

26. 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 A device that draws out the air and vapours which are released from the condensing steam in the condenser. 6A heat exchanger used to reduce the temperature of the water drains before entering the feed tank. 7 The pump that raises the feedwater to a pressure high enough to enter the boiler. 8 The tank at atmospheric pressure to which condensed water from auxiliaries, heating coils etc. is led. 9 A chamber in which exhaust steam is led to change back into water.

27. Exercise 1 – KEY air ejector (vacuum pump), atmospheric drain tank, condensate extraction pump, condenser, de-aerator, economiser, feed pump, low pressure heater, superheater 5 A device that draws out the air and vapours which are released from the condensing steam in the condenser. air ejector (vacuum pump) 6A heat exchanger used to reduce the temperature of the water drains before entering the feed tank. low pressure heater 7 The pump that raises the feedwater to a pressure high enough to enter the boiler. feed pump 8 The tank at atmospheric pressure to which condensed water from auxiliaries, heating coils etc. is led. atmospheric drain tank 9 A chamber in which exhaust steam is led to change back into water. condenser