Cooling structure for an oil sealed rotary vacuum pump

摘要

An oil pool in a rotary vane, oil sealed mechanical vacuum pump casing is cooled by air drawn by a relatively low pressure and low speed laminar flow fan mounted on a motor shaft for the pump and positioned in a shroud between end plates for the motor and casing. The air pumped by the fan flows axially relative to the shaft through a horizotally extending slot at the bottom of the shroud and vertically extending slots on the sides of the shroud. The pumped air flows against vertically and horizontally extending fins respectively on the pump casing bottom and sides. The vertically extending fins at the bottom of the casing have bases slightly above the horizontal slot at the bottom of the housing so air flowing through that slot flows against the bases of the fins at a shallow angle. A vertical surface of the housing remote from the fan and the shroud has vertically extending fins that are aligned with the vertically extending fins on the bottom of the casing.