These VS4 API 610 compliant vertical pumpsets complete with 37 kW x 2950 rpm Zone 1 motors and gas gland shaft entry sealing have been supplied for a contract in Kazakhstan. They incorporate PATS' usual design features, including our unique floating bush lineshaft bearing technology. Because of sand contamination of the crude oil being pumped it was necessary to ensure that a genuinely clean lubricant is available to these high-speed sleeve bearings. No site service fluid was available at the remote installation location.
Cyclone separators were considered but these require a considerable r p across them and have very small internal passageways in the sizes appropriate to bearing feed flows. There is no guarantee of 100% solids separation.
The solution was an oil filled column, an old idea but found lacking in the past because failure of the bottom sealing device inevitably led to lineshaft bearing failure. Our answer has been to incorporate a belt driven oil pump/reservoir system; similar to that used on our grease lubricated designs. Grease was not thought suitable for these high speed bearings because of the lack of heat removal capability.
In this case the oil is injected only into the top bearing, the column having been pre-filled. There is a pair of overflow holes in the top column, just below the mounting plate. As long as the bottom column seal does not leak then the volume of oil injected constantly overflows from these holes back into the main body of the pumped fluid. Should the lower seal fail then a weir system comes into play from the top bearing downwards meaning that each bearing receives a constant supply of oil. Repeller blades on the back of the impeller ensure that there is a low-pressure area on the pumped liquid side of the bottom seal. The reservoir vessel holds sufficient oil to enable operation for up to 21 days at 24 hr/day running. End User : Petrochemical, Russia