The Positive Displacement meter, like the turbine meter has been the traditional method of metering for the last six decades.
Positive Displacement meters provide a high level accuracy and can be used to meter oil with high viscosity. Their size, weight and vulnerability to internal damage, makes them unsuitable for offshore installations. They are a better choice for onshore terminals and industrial plants and are very frequently the preferred method of measurement for Tanker loading and unloading operations.