A secondary working standard of flow calibration has been developed to be used in place of a primary weight-time standard, and which can thereby effect a 75 percent reduction in calibration time while maintaining acceptable accuracies. The secondary standard uses six previously calibrated turbine-type flowmeters built into two manifold systems containing automatically switched flow valves. The pair of systems is capable of covering the flow range of 0.0004 to 19 1/s (0.007 to 300 gpm) with the uncertainty in volume flow rate not exceeding ±0.25 percent over the range 0.06 to 19 1/s and not exceeding ±0.5 percent over the range 0.0004 to 0.06 1/s. Data reduction and plotting of re¬sults are by computer.
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