A manufacturer of cryogenic 2-stage overhung pumps needed a non-galling bearing material that could survive shaft contact, be oxygen compatible and perform in cryogenic temperatures.
The manufacturer’s 2-stage, cryogenic pumps are used in the liquid gas industry. These units operate at up to 8000 rpm and can pump liquid oxygen at a temperature of minus 320°F (-195°C). The 2-stage design is required to meet the design point of 70 gpm of flow and 1,020 ft. of total differential head.
Due to the shaft length required for the 2-stage pump, shaft deflection leads to a number of issues including contact, rubbing and excessive wear. A tighter fitting bushing can add support to the shaft and can be mounted between the two impellers in the diffuser.
This solution required a material with the properties to withstand the loading and contact with minimal wear. In addition, the material had to be oxygen compatible and reliably perform within cryogenic temperature ranges. The pump manufacturer contacted Graphite Metallizing Corporation...