Systems and methods for pressure measurement are provided. A ludion with a trapped gas bubble floats between two liquids. Pressure acting upon the liquids causes the bubble to expand or contract, resulting in movement of the ludion which can be measured and correlated with pressure change. Pressure measuring device can measure pressures from 0.05 inHg to 110 inHg with a four-to-one Test Accuracy Ratio (TAR) without using mercury.

Systems and methods for pressure measurement are provided. A ludion with a trapped gas bubble floats between two liquids. Pressure acting upon the liquids causes the bubble to expand or contract, resulting in movement of the ludion which can be measured and correlated with pressure change. Pressure measuring device can measure pressures from 0.05 inHg to 110 inHg with a four-to-one Test Accuracy Ratio (TAR) without using mercury.

The invention relates to a pore pressure monitoring device, for use in geotechnical engineering, adapted to be deployed underground for monitoring pore-water pressure in the ground, comprising a pressure sensor cavity (2) and a pressure sensor means (4), for sensing a fluid (6) pressure of a fluid in the sensor cavity (2), further comprising a degassing means (10), comprising a gas discharge means (14) and a gas-water filter means (12), wherein the gas-water filter means (12) is adapted for providing a route for gas (8) to escape from the fluid (6) in the sensor cavity (2), towards the gas discharge means (14) for discharging the filtered gas (8) to the atmosphere. The invention also relates to a method for monitoring pore-water pressure.

A high-temperature gas pressure measuring method includes a pressure measuring gas housing dividing step for dividing a pressure measuring gas housing into a pressure measuring room and a pressure referring room by a metal diaphragm; a gas introducing step for introducing high temperature gas into the pressure measuring room and introducing a reference pressure gas into the pressure referring room; a displacement measuring step for measuring a displacement of the metal diaphragm, wherein the displacement is caused by pressure difference between the two rooms in pressure measuring gas housing; and a pressure determining step for measuring the pressure of a high-temperature and/or corrosive to-measure pressure gas. The method dispenses with any corrosion-resistant and heat-resistant pressure sensing component and thus cuts costs.

A high-temperature gas pressure measuring method includes a pressure measuring gas housing dividing step for dividing a pressure measuring gas housing into a pressure measuring room and a pressure referring room by a metal diaphragm; a gas introducing step for introducing high temperature gas into the pressure measuring room and introducing a reference pressure gas into the pressure referring room; a displacement measuring step for measuring a displacement of the metal diaphragm, wherein the displacement is caused by pressure difference between the two rooms in pressure measuring gas housing; and a pressure determining step for measuring the pressure of a high-temperature and/or corrosive to-measure pressure gas. The method dispenses with any corrosion-resistant and heat-resistant pressure sensing component and thus cuts costs.