The Sump has two primary fuctions.
The first, is the storage tank for the compressor hydraulic oil.
The 2nd, is the first of 2 stages in the separation of the hot hydraulic oil and hot compressed air.
The opposing screws type compressor requires hydraulic oil to keep the screws turning. As air is pulled in and compressed, it is mixed with the hydraulic oil. Only the air compresses. The oil does not. However, the compression generates heat that heats both the air and oil. The combined hot oil and air leave the compressor and head 1st to the Sump. The hot oil drops to the bottom of the tank like Sump while the hot air rises to the top. The air then heads towards the Air/Oil Separator. The hot oil heads to the the heat exchanger for cooling and reuse in the compressor.
The Sump may come in different shapes depending on the manufacturer and system model, however, they all have the same two functions.
The Sump also incorporates the Site Glass that allows the operator to both check the oil level prior to operations, and again periodically during operations.
