Lubrication system for a vertical gear unit

Claim 1

In a vertical gear unit having a downwardly extending output shaft, a motor for driving said shaft connected to the upper end thereof, and an impeller driven by said shaft connected to the lower end thereof, upper housing means defining an upper lubricating oil sump having lubricating oil stored therewithin, and lower housing means defining a lower lubricating oil sump for collecting lubricating oil exiting from a bearing for said shaft, said upper and lower housings being assembled and vertically spaced about the output shaft, with the upper housing being disposed vertically above the lower housing, wherein the improvement comprises: said lower housing means having a surface facing said upper housing means, a first groove formed in the surface of the lower housing means which defines a first passage when said upper and lower housing means are assembled, said first passage being in communication with the lower sump, a second groove being formed in the surface which forms a second passage when said upper and lower housing means are assembled, said second passage also in communication with the lower sump, said first and second passages extending in a radial direction from the rotational axis of the output shaft from the lower sump to the exterior of the vertical gear unit; pneumatic purge means for supplying air into said lower sump through said first passage for increasing the pressure therewithin to a level above the pressure within the upper sump; conduit means connecting the upper and lower sumps through the second passage, with the relatively high pressure within the lower sump driving the lubricating oil collected therewithin upwardly into the upper sump; a first labyrinth seal sealing between the upper housing means and the rotating downwardly extending output shaft and a second labyrinth seal sealing between the lower housing means and the rotating downwardly extending output shaft to isolate the lower sump from the upper sump to maintain the relatively high pressure within the lower sump.