Foaming of the unit lubricating oil
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Is it normal for the lubricating oil from unit 2291 to contain foam after coming out of the bearing housing? Is it better to have more foam, or less foam?
During operation, the lubricating oil in the engine generates bubbles due to friction and agitation; these bubbles are known as foam. An appropriate amount of foam is beneficial for the movement and cooling effects of the lubricant, but excessive foam can impair the lubrication performance and even cause unit failures. Therefore, excessive foam is undesirable, and appropriate measures should be taken to reduce it. It can operate normally with less foam, but it is necessary to regularly check the quality and quantity of the lubricating oil. .
First, we need to understand the reasons behind the formation of this foam. 1. Those caused by flow velocity disturbances, as shown in the video, are normal. 2. Some bearing housings need to operate under negative pressure. When this negative pressure is lower than the designed value, air enters at the shaft seal, resulting in an increase in foam; this can lead to oil leakage at the seal, and in severe cases, it can obstruct the oil return system. If this phenomenon appears later on, it’s best to try reducing the value of systemic negative pressure. If this state is maintained, and it is normal for the foam to stay in this condition for a long time as well. For reference.
It’s usually normal; disturbances can cause bubbles, but as long as the test results remain within the normal range, it’s fine
From the video, it appears that the oil level in the return line sight glass is very low and the flow rate is high; could it be due to excessive negative pressure? If you are worried, you can check the fuel tank online or take a sample for foam analysis