Abstract: A pressure gauge includes: an outer container defining an outer chamber set to a reference pressure (Pr); an inner container disposed in the outer container; and a tube setting the inside of a first inner chamber of the inner container to a measurement pressure (Px). The inner container includes: a cylindrical rigid wall portion; first and second pressure receiving plates that displace due to a differential pressure between the reference pressure and the measurement pressure; a bellows partitioning the inner container into the first inner chamber and a second inner chamber; and a pressure detection element disposed in the second inner chamber and detecting the measurement pressure based on the displacements of the first and the second pressure receiving plates. The outer chamber and the second inner chamber are set to the reference pressure of a high vacuum that is lower than a lower limit of the measurement pressure.

Abstract: A vacuum gauge includes an introduction tube, a diaphragm displaced by a gas to be measured that is introduced from the introduction tube, a piezoelectric element that has one end coupled to the diaphragm and is displaced along with the diaphragm, an inner structure to which a circumferential edge of the diaphragm and the other end of the piezoelectric element are secured and that is coupled to the introduction tube, and an airtight container to airtightly enclose the introduction tube and the inner structure. The inner structure, the introduction tube, and the diaphragm airtightly partition a space in the airtight container into a pressure introduction chamber to which the gas to be measured is introduced on one surface side of the diaphragm, and a reference pressure chamber on the other surface side of the diaphragm. the reference pressure chamber being set at a high vacuum that is lower than the pressure lower limit of the measurement gas.

Abstract: A pressure gauge includes: an outer container defining an outer chamber set to a reference pressure (Pr); an inner container disposed in the outer container; and a tube setting the inside of a first inner chamber of the inner container to a measurement pressure (Px). The inner container includes: a cylindrical rigid wall portion; first and second pressure receiving plates that displace due to a differential pressure between the reference pressure and the measurement pressure; a bellows partitioning the inner container into the first inner chamber and a second inner chamber; and a pressure detection element disposed in the second inner chamber and detecting the measurement pressure based on the displacements of the first and the second pressure receiving plates. The outer chamber and the second inner chamber are set to the reference pressure of a high vacuum that is lower than a lower limit of the measurement pressure.

Abstract: A vacuum gauge includes an introduction tube, a diaphragm displaced by a gas to be measured that is introduced from the introduction tube, a piezoelectric element that has one end coupled to the diaphragm and is displaced along with the diaphragm, an inner structure to which a circumferential edge of the diaphragm and the other end of the piezoelectric element are secured and that is coupled to the introduction tube, and an airtight container to airtightly enclose the introduction tube and the inner structure. The inner structure, the introduction tube, and the diaphragm airtightly partition a space in the airtight container into a pressure introduction chamber to which the gas to be measured is introduced on one surface side of the diaphragm, and a reference pressure chamber on the other surface side of the diaphragm. the reference pressure chamber being set at a high vacuum that is lower than the pressure lower limit of the measurement gas.