GB962470A - Improvements relating to apparatus for determining changes in volume of materials subjected to liquid pressure - Google Patents

Abstract

962,470. Measuring volume changes; testing soil. SOIL MECHANICS Ltd. Sept. 4, 1962 [Sept. 6, 1961], No. 32027/61. Headings G1S and G1X. A U-tube device, for use in apparatus for measuring changes in volume of soil samples with respect to time under a constant water pressure, comprises a U-tube formed by two bores 2, 3 and a connecting cross-passage 5 in a block of transparent material e.g. "Perspex" (Registered Trade Mark), which has in it, at its end remote from the cross-passage 5 a by-pass passage 15 provided with a closure valve 16. The device has two inlet unions 7, 8, the union 8 being connected to a tube 9A leading to the soil sample: Passages 7, 13 leadine from the union 7 communicate wjth the bore 2, and passages 14,10 lead from the bore 3. An air vent passage 11 closed by a valve 12 is also provided. The lower part of the U-tube contains a liquid immiscible with water e.g. a fluorocarbon, and the rest of the device is filled with water. The valve 16 has two reduced portions 17, 18 separated and sealed by rubber O-rings 19, 20, 21, in the bypass passage 15. With'the valve 16 in the position shown, the passages 13, 14 communicate with the bores 2, 3 respectively and as the soil sample decreases in volume, the water-immiscible liquid interface rises up the bore 3, the movement being measured by graduations on the outside of the transparent block. When the interface reaches the top of the bore 3, the valve 16 is moved to the left in the drawing so that the passages 13, 14 and the top ends of the bores 2, 3 all communicate via the reduced portion 17, and the interface level in the bore 3 falls until it is level with that in the bore 2. By returning the valve 16 to the position shown a further set of readings of the change in volume of the soil sample may be obtained. The device may be used as an inverted U-tube,if desired.