Oil equalization system for parallel connected hermetic helical screw compressor units

摘要

A pair of helical screw rotary hermetic compressor units are connected in parallel across common suction and discharge manifolds. The discharge manifolds open to each unit casing well above the level of accumulated oil within the bottom of the hermetic casings acting as oil sumps. Oil bleed lines are provided for the casings which open to the casing interior at oil bleed ports at the normal level of accumulated oil. The bleed lines are of small diameter and open directly to the discharge manifold at points downstream of the connection between the discharge manifold and the hermetic casing. Excessive accumulation of oil within one of the hermetic compressor casings causes the oil to bleed through its bleed line under a small pressure differential to the discharge manifold for redistribution to the remaining compressors.