These reservoirs may be used with the oil separator and an oil level regulator to return oil to the compressor.
Oil Reservoirs are necessary on multiple, parallel compressor systems. They act as a holding vessel ready to feed oil to the oil level regulators as needed to maintain the proper oil level at each individual compressor and are essential for maintaining the proper balance of oil throughout the system. The valve at the top receives the oil from the oil separator while the valve at the bottom distributes it to the compressor crankcases. The top valve provides a convenient access port for adding oil to the system and the bottom valve likewise provides an access valve for removing oil if necessary based on the level indicated by the sight glasses. There is also a fitting at the top to attach the vent line with the pressure differential valve which regulates the pressure in the reservoir.