Centrifugal pump oil cup and lubricant level
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The oil cup of the centrifugal pump is integrated with the bearing housing; why is the level of oil in the oil cup different from the level of lubricating oil in the sight glass of the bearing housing? Oil is added from the bearing housing, and the level in the oil cup remains unchanged. Is there a specified level for the oil in the cup? What is the purpose of the oil in the oil cup? It’s not for indicating the liquid level, right?
This oil cup is known as a constant-level oil cup; it is designed to maintain a constant oil level inside the bearing box. When the oil level in the bearing box drops, the oil cup automatically compensates for this. The difference in oil levels you mentioned is due to the liquid seal at the lower part; in other words, the outlet of the oil cup is below the oil level in the bearing box, so the oil cannot flow out.
Reply to 2# 6862798: What is the principle of automatic compensation? Is it the principle that the head pressure generated by the liquid level in the bearing housing is balanced by the head pressure generated by the gravity of the oil in the oil cup? So, by explaining it that way, does filling the oil cup mean adding oil directly from above?
The outlets of the oil cups are all above the oil level gauge in the bearing box, and the specified oil level is at 1/2 to 2/3 of the level indicated by the gauge. Clearly, the oil in the oil cups is at a level higher than that in the bearing box, yet the oil is added in small amounts only. How can this be explained?
I suggest you take a look at the structural principle of the constant-pressure oil cup.
I don’t understand either; I’ve been learning * lately and hope an expert can give some guidance