| 摘要 |
A calibration system for a tube prover used in gas flow rate calibration equipment includes a low friction piston which provides an effective seal without the use of mercury. The low friction piston is easily movable in a prover tube of the calibration system in response to gas flow rates, even low flow rates. The piston is constructed of a light weight, low friction fluorinated hydrocarbon material. The piston has first and second seals which provide a positive seal with the inner surface of the prover tube and which maintain the alignment of the piston within the prover tube.
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