Flow meters for the PAT loop

The flow of coolant in the PAT loop at temperatures in the range 2000C to 6000C and a pressure of 40 bar must be measured accurately. It is not possible to provide good upstream flow conditions for a flow meter in the complicated pipework or to calibrate a flow meter in the loop itself. Two independent combined flow conditioner and orifice meter units for subsequent insertion into the loop were designed, built and independently calibrated. The discharge coefficient was determined over the working range of Reynolds number by comparison with a standard orifice plate in the WNL high pressure gas loop. Tests at atmospheric pressure have demonstrated that, to the accuracy of measurement, the discharge coefficients of the units are unaffected by disturbances to the upstream flow. (author)