The history of orifice metering began in the early 1900’s. The first test data was done by the U.S. Geological Survey and in 1913 the first “Handbook of Natural Gas” was published. So, as you can tell, orifice metering has been around for over 100 years and in that time, much has been learned and improved on.

Orifice metering flow equations have been derived from test data where an orifice plate, a plate with a hole in the middle of it, was placed in the flow line causing a restriction in flow. This differential was then compared to the actual amount that passed by the orifice and from that information engineers can then ascertain by mathematical algorithms what equations to use to duplicate those results. Below is a schematic of an orifice differential being compared to a known prover volume.