ピストン式プルーバの試作

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A new high efficiency piston-type meter prover as a standard flowmeter has been developed.
The specifications are as follows.
1) Cylinder: The inside diameter of steel cylinder is finished 700.13±0.02mm.
2) Piston: Two self seal packings, oil ring and teflon ring for supporting piston are wound outside the steel piston.
3) Capacity: About 0.5m³.
4) Actuator: The piston is driven by a thyrister controlled moter and a precision ball screw.
5) Effective range: 0.2∼80m³/h.
6) Indicator: Angular displacement of driving gear is directed by a rotary encorder and the flow rate or the total volume is indicated digitally.
7) Accuracy: About 0.03%.
8) Resolution: 6.6×10^-6m³.
Compared with a conventional type meter prover, merits of the new device are as follows.
9) A large class of gases or liquids are acceptable for calibration.
10) Temperature control and measurement are easy, so that the error due to unstable is very small.
11) The calibration of a flowmeter such as that of Kármáns vortex type can be performed by this device with a high accuracy, as the flow rate is very stable throughout the full range.
12) A large capacity displacement meter can be also calibrated with a high accuracy by this prover.