Another problem common to all turbine flowmeters is lubrication of the turbine bearings.
Frictionless motion of the turbine wheel is essential for accurate flow measurement, which is a
daunting design goal for the flowmeter manufacturing engineers. The problem is not as severe in
applications where the process fluid is naturally lubricating (e.g. diesel fuel), but in applications
such as natural gas flow where the fluid provides no lubrication to the turbine bearings, external
lubrication must be supplied. This is often a regular maintenance task for instrument technicians:
using a hand pump to inject light-weight “turbine oil” into the bearing assemblies of turbine
flowmeters used in gas service