Translate from Russian into English. 1. Подшипники паровой турбины являются промежуточным звеном между ее ротором и

 

1. Подшипники паровой турбины являются промежуточным звеном между ее ротором и статором.

2. Подшипники, служащие опорой для ротора, называются опорными.

3. Они предназначены для центрования ротора в радиальном направлении, восприятия веса ротора и сил, возникающих при его вращении.

4. Опорные подшипники главных турбин работают с большими окружными скоростями.

5. Для надежной работы к подшипникам должно непрерывно подводиться масло, которое одновременно охлаждает подшипник.

6. Опорные подшипники турбин имеют цилиндрические и шаровые опоры, в зависимости от которых они делятся соответственно на жесткие и самоустанавливающиеся.

7. Упорный подшипник воспринимает на себя осевые усилия, возникающие во время работы ротора, и удерживает его в осевом направлении.

8. Как и опорные, упорные подшипники делятся на жесткие и опорно-упорный подшипник.

9. Вкладыши опорных и упорных подшипников помещают в корпуса, устанавливаемые самоустанавливающиеся.

10. Часто упорный подшипник объединяют с опорным, т.е. получается комбинированный на фундамент, или присоединяемые непосредственно к корпусу турбины

 

UNIT 10

OPERATING PROCEDURES

 

Successful operation of the turbine depends on the manner of the warming through, loading, stopping and cooling down of the turbines. Steam turbines are built and operate with very close tolerances in their structure, and the very nature of the driving medium can lead to problems associated with thermal expansion unless due care is taken. Correct warming through and proper drainage is essential together with careful handling of load changes. A minimum of 90 minutes notice will normally be provided by the bridge for the warm up procedure.

The preparation of the turbine for use is the responsibility of the operator. Correct loading up times are programmed into the turbine control system, as are the opening of the drain valves and bleeds. Should any of these functions need to be carried out manually, they should be done in the same manner as the automated function.

Steam Turbines Warming Through

The turbines are to be warmed through gradually following a stay in port or other occasion when they have been shut down. The bulkhead, stop, and manoeuvring valves are to remain shut. Warming through is to commence, not less than 12 hours prior to the estimated time of departure. The Deck Officer of the watch, or Duty Deck Officer is to be contacted and permission to turn the turbines/propeller requested. Once the Deck Officer has confirmed that this can safely be carried out then and only then can the turbines be turned. Lubricating oil circulation is to be started, and low vacuum created. Rotation can then commence after which the gland steam can be opened gradually. On no account is gland steam to be admitted with the turbine rotors stationary. The temperatures are to be raised to the manufacturers’ recommendations. Once this has been achieved the turning gear can be disengaged. It is the responsibility of the Chief Engineer Officer to ensure that disengagement of the turning gear is physically sighted. No reliance is to be placed on any remote indicating devices. A request is then to be made to the Officer of the watch on the bridge for permission to turn the engine on live steam.

Normal Operation

The main engine is to be operated within the limits of power, maximum evaporative capacity and pressure of the boilers, and the revolutions per min set out in the commissioning letter issued when the vessel entered Company service. Only if subsequent specific instructions have been issued by the Company, are the original commissioning letter parameters to be countermanded.

Stand By Manoeuvring

The Officer of the watch on the Bridge must give the Engine Department at least one hours notice before Stand By for manoeuvring. Regardless of the time of day or type of vessel i.e. unmanned engine room or conventional watchkeeping, the Chief Engineer Officer, and the Engineer Officer of the watch or Duty Engineer Officer are to be informed. Reduction in speed from full speed to the recognisedmanoeuvring speed is to be as gradual as possible and in accordance with the manufacturer’s instructions. The operating parameters are to be maintained avoiding sudden variations of boiler loading etc.

Cooling Down

When the main turbines are stopped and " Finished with Engines" has been rung, the nozzle control, manoeuvring, guardian, bulkhead and stop valves are to be shut and verified as shut. As soon as the above mentioned valves are verified as shut, permission is to be sought from the Officer of the watch on the Bridge to turn the turbines/propeller. Once permission is granted, then the turning gear is to be engaged and the turbines rotated with the lubricating oil supply maintained, low vacuum, and gland steam on, over a minimum period of 4 hours. Maintaining Temperatures during Short Stays in Port If the ETD is six hours or less then the following procedure is to be adhered to. Following " Finished with Engines" permission is to be sought to turn the turbines/propeller on live steam. With the lubricating oil supply maintained, low vacuum, and gland steam on the turbines are to be turned on ahead steam for approximately 2 propeller revolutions every five minutes, using astern steam as appropriate for checking ahead rotation only.

 

EXERCISES

 

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