The TRG diverter valve fig. 1 is a 4way valve which diverts flow through the Bi-Directional Prover without blocking the main stream.

When metering a liquid with a flow meter, precise flow measurement is not possible, no matter how accurate the meter may be, if entrained air or vapor is present in the liquid. Experience shows that such entrainment often takes place at the beginning or at the end of a given metering run. An air eliminatory is used to remove entrained air and vapor before the liquid enters the meter to ensure correct flow rate Measurements .

TRG Straightening Vanes are installed in the upstream section of meter tubes to reduce flow disturbance preceding the orifice plate.