2015-10-22
472
Temperature of coolers is controled by adjusting the cooling liquid outlet valve. The inlet valve is left open which ensures a constant pressure within the cooler. This is very imports with sea.water cooling where reducing pressure can result in air remaining in a cooler which will considerably reduce the cooling effect. Vents provided in the highest point of coolers should be opened on first filling and occasionally afterwards. Drain plugs are also fitted at the lowest point in coolers.
The plate heat exchangers should be opened and cleaned regularly аnd under normal circumstances every six months. The O-rings in the connections, the gaskets and the sealing surfaces on the back of the plate should be checked before the heat exchanger is reassembled.
| Symptom: | Cause: | Remedy: |
| 1. Reduced cooling efficiency. | a) Deposits | a) Check the heat transfer surface for deposits and if arty remove them. |
| b) The flow rates for oil and water are incorrect. | b) Check that flow rates for oil and water are correct. | |
| 2. Leakage visible on the outside of the plate pack. | a) The plate pack is not tightened enough. | a) Tighten the plate pack further. |
| b) The gaskets and sealing surfaces are not clean and-the plates are deformed. | b) Replace the gaskets and the damaged plates. | |
| c) Corrosion between the double gaskets or in the same area of the adjoining plate. | c) Replace the gaskets or the plate | |
| 3. Fresh water or lubricating oil volumes decrease in the respective systems. | There is a hole in the plate. | Remove the lower sea water valve, apply a test pressure on the opposite side and, if liquid flows from the side under pressure, replace the faulty plate. |
Exercise 1. Answer the questions.
1) What is pump designed for?
2) For what services are pumps used on board ship?
3) Prove the importance of maintaining the pumps in efficient working order.
4) What jobs is an engineer required to do on pumps?
5) What parts are the most troublesome in an air compressor?
6) Why may seats require to be refaced?
7) What may cause sticking or pitting of the surface?
8) What ensures a good seal in a compressor?
9) How is temperature of coolers controlled?
10) What are cooler drain plugs for?
11) How often should the plate heat exchangers be cleaned?
Exercise 2. Give the Russian equivalents of the following.
1) sea water cooling
2) sealing surfaces
3) suction and delivery valves
4) operating temperatures and pressures
5) air vent
6) discharge check valve
Exercise 3. Give synonyms.
| 1. To supply | 6. Piston | 11. Fouled |
| 2. Entire | 7. Suction valve | 12. Internal |
| 3. To transfer | 8. To force | 13. External |
| 4. Operational repairs | 9. Vane | 14. Aircock |
| 5. Suction head | 10. To utilize |
Exercise 4. Supply suitable words.
boiler, discharge pressure, a two-stage centrifugal pump, feed pumps, capacity
1) What is the duty of.............. pump?
2) Name the pump required...................?
3) This is a.............................
4) One of the most widely used................... Is manufactured by the FMC Corp. under the name of Coffin.
5) Tell the............ of the pump.
Exercise 5. Compose the sentences, sterting them with he phrase.
1) See that...................
2) The pump...... to develop........... correct pressure and flow.
3) The temperature............ not to exceed............ that specified.
4) All electric connections.............. to be properly made.
5) All covers............... to be securely replaced.
6) The pump and motor.............. to run quietly.
7) Mechanical shaft seal............. not to leak.
8) The motor............. not to overheat.
9) The strainer fitted to the unit............. to be clean.
Exercise 6. Compose sentences of your own with following words.
1) Plug - заглушка
2) Cap-nut - гайка - колпачок
3) Bolt - болт
4) Pump casing - корпус насоса
5) Key - шпонка
6) Seal ring - уплотнительное кольцо
7) Pin - болт, штифт
8) Stud - шпилька
9) Cover - крышка
10) Pipe-труба
11) Impeller - крылатка
12) Shaft - вал
13) Screw - винт - болт
14) Packing - набивка
Exercise 7. Translate into English.
1) Производительность центробежного насоса равна 150 мЗ/ч.
2) Насосы спроектированы для подачи пресной и морской воды.
3) Корпус (casing) нacoca снизу закрывается крышкой (cover).
4) Половинки корпуса насоса крепятся болтами.
5)Капли жидкости могут просачиваться (seep, infiltrate) через уплотнения (packing).
6) Зазор между уплотнениями очень мал.
7) Крылатка насаживается на вал н фиксируется шпонкой (key). (Impeller is keyed to the shaft).
8) Мощность этого насоса 14 л.с. (h.p.) при частоте вращения вала 1400 об/мин.
9) Электромотор связан с насосом посредством муфты (coupling).
10) Вал проходит через корпус насоса (casing).
11) Клапаны всасывания и нагнетания следует разобрать и тщательно вычистить, а изношенные детали заменить.
12) Теплообменники следует регулярно вскрывать и чистить – обычно каждые 6 месяцев.
Exercise 8. Make up a dialogue of your own based on the dialogue given below.
THE HEAT EXCHANGERS AND SEA WATER LINES
Notes:
| heat-exchange equipment | теплообменное оборудование |
| cooler | охладитель |
| in the first place | в первую очередь |
| sea-water line | трубопровод забортной воды |
| gusset stay (tie rod, tie bolt) | анкерная связь |
| ultrasonic test | ультразвуковой контроль |
| microcrack | микротрещина |
| tighten | затянуть |
Mr. Wilson- - Well, Let's see what should be done with the heat exchange equipment Shall we replace the oil and water coolers?
Ch. Engineer: No, I don't think so. Cleaning and hydraulic testing, that's what they need in the first place. Their cooling efficiency is very reduced I think that the heat transfer surface must be cleaned of deposits. Besides that you should replace O-rings in the connections and the gaskets. After the hydraulic test we'll see if something else is necessary.
Mr. Wilson: And what about the sea- water lines for the main engine?
Chief Eng.: You see we did not include them in the part concerning the main engine repair but they are listed in the part connecting with the auxiliary diesel - generators.
Mr. Wilson: Can you clarify the item about the gusset stays (tie rods)?
Chief Eng.: Oh, most willingly. The gusset stays should be subjected to the ultrasonic test for rnicrocracks and then fitted into position and tightened in accordance with the instruction.
Mr. Wilson: Thank you. Now, we are quite clear about this item.
Exercise 9. Speak on the following.
1) The most frequent operating troubles of the pump.
2) Air compressor maintenance.
3) Water cooler maintenance.
Exercise 10. Complete the sentences.
1) During valve adjustment it is necessary....
2) If the compressor is automated, it is necessary....
3) If the capacity is less than nominal, the reason may be......
4) The reason of large oil consumption may be........
5) If there is some abnormal noise and vibration in the compressor, it may be caused by....
