It is an metering point where the fluid is being measured for sale from one party to another. Due to the high level of accuracy required during custody transfer applications, the flow meters which are used to perform this are subject to approval by an organisation such as the American Petroleum Institute(API).
Flow computers are used to monitor and calculate the volume and mass flows in gathering and transportation pipeline systems for natural gas, crude oils, refined products, LPGs.
KROHNE Flow Computer model Summit 8800: