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In the previous article we had studied about the cylinder lubrication system in marine diesel engines and a passing mention was made about the cylinder lubricators which supply oil under pressure to the lubricating quills located on the cylinder liner. This article is devoted to studying one of such cylinder lubricators in details used in modern Sulzer engines and is the IVO lubricators. It would help to give a fair idea to the readers about the internal workings of such a system.
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IVO Cylinder Lubricator
I would strongly suggest that you correlate what you read in this article with the diagram otherwise it will be very difficult to get a mental image of what is being described. The sketch shown in the figure gives a schematic diagram of the IVO cylinder lubricator and the parts are labeled as follows.
1. Pump shaft
2. Gear shaft
3. upper and lower outlet pipes
4. control plunger
5. main plunger
6. pump element
7. twisted disc for control plunger
8. twisted disc for main plunger
9. set-screw for adjustment
10. inlet pipe
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The Actual Working
After you have taken a look at the IVO lubricator diagram it is time to understand how things actually work.
The gear shaft is rotated through the pump shaft using rack and pinion gear arrangement. This gear shaft has got two twisted discs or plates which move through appropriate grooves in two plungers so that when the gear shaft moves in a rotary fashion, the discs make the two plungers move in to and fro motion depending on the disc geometry. The suction or inlet pipe draws lubricating oil from a reservoir which is taken up into the pump chamber when the control plunger connects the same to the inlet pipe. The main plunger pumps the oil into the two outlet pipe one at a time. The arrangement is such for every to and fro motion of the control plunger, the main plunger does this motion twice.
The set screw shown in the diagram can be used to control the delivery amount of the lubricating oil to the quills fitted in the liner about which we already studied in the previous article. Also it must be noted that the oil from the lubricating pump going to the quill gets discharged twice inside the liner during each revolution of the main engine crankshaft – once during the beginning of the expansion stroke as the piston is moving downwards and secondly during the end of the compression stroke.
Having learnt about the IVO lubricator we will now study the system used for crankcase lubrication in our next article.