… Gas, liquid or electricity supply or production meters, including calibrating …
Explanatory notes
… METERS These meters are used to measure in volumetric units the amount of fluid passing through a pipe. Flowmeters, … in two compartments by a partition. Each compartment is itself divided by a central diaphragm; the gas passes … a partitioned spherical chamber. The meters referred to in items (2) to (5) above are known as positive displacement …