Abstract: For developing constantpressure l gas micro-flow meter, the bellows variable volume chamber has been designed. And the section area has been measured. The section area value of bellow variable volume chamber is corrected by polynomial formula to avoid non-linearity effect of bellows. The corrected deviation is less than 0.16%, and the relative combined standard uncertainty of measurement is less than 0.53%.

Key words: ⁺Constant-pressure gas flow meter, ⁺Bellow variable volume chamber, Section area, Correction a measurement