| 摘要 |
PROBLEM TO BE SOLVED: To remove sufficiently the influence of thermal expansion by shortening to the utmost the distance between a high sensitivity sensor and a low sensitivity sensor. SOLUTION: In this pressure change measuring device, the change of an inner diameter of a cylindrical vessel is detected, and thereby the pressure change applied to the cylindrical vessel is measured. The cylindrical vessel is classified into a thin-walled part 1 and a thick-walled part 2, and the change of each inner diameter D<SB>1</SB>, D<SB>2</SB>of the thin-walled part 1 and the thick-walled part 2 is detected, and the difference (ΔD<SB>1</SB>-ΔD<SB>2</SB>) of the changesΔD<SB>1</SB>,ΔD<SB>2</SB>of each inner diameter is determined, to thereby measure the pressure change applied to the cylindrical vessel based on the difference. The thin-walled part 1 and the thick-walled part 2 are used as the high sensitivity sensor and the low sensitivity sensor respectively, and the distance between the sensors is shortened to the utmost, to thereby enable to remove sufficiently the influence of the thermal expansion. Even if the temperature is changed suddenly, the influence can be reduced furthermore by heightening the thermal conductivity or the thermal diffusion coefficient of the cylindrical vessel and by lowering the coefficient of thermal expansion, and the pressure change can be measured. COPYRIGHT: (C)2003,JPO
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