Tube profile gage

A tube profile gage for measurement of vertical settlement or vertical heave throughout the length of a conduit affixed to, or located within or beneath any civil works, such as structures, dams, or terrestrial formations;

• including land slides, or subsiding ground surfaces, said gage comprising a measurement traverse of a conduit along the required route of observation for vertical movement of the works, such conduit being of flexible, pressure tight construction, with the ends of the measurement traverse conduit brought to some convenient, accessible terminal location relative to the works, for connection to readout cabinet, with means in the cabinet of flushing and completely filling the said measurement traverse with a light density fluid, with further means of then introducing a heavy density fluid from the cabinet into one end of the measurement traverse, with further means in the cabinet of regulating the rate and duration of advance of the heavy density fluid into the measurement traverse and the light density fluid out of the measurement traverse, with means of determining the distance of travel of the heavy density/light density fluid interface into the measurement traverse, with further means of continuously maintaining a surface level of heavy density fluid in the cabinet at a constant reference elevation irrespective of the amount of heavy density fluid supplied from the cabinet into the measurement traverse, with means of determining the hydrostatic pressure resulting from the vertical position of the heavy density/light density fluid interface with respect to the constant elevation of the said surface of the heavy density fluid in the cabinet, and thereby discovering the true vertical distance between the said fluid interface and the known elevation of the surface of the heavy density fluid in the cabinet, with further means of automatically recording and calibrating the hydrodynamic pressure variation produced by a continuously moving fluid interface, at a recording time rate proportional to the rate of travel of the fluid interface through the measurement traverse, thereby producing the digital data or actual scaled drawing of the existing elevation profile for the measurement traverse, which may be compared with earlier elevation profiles to discern the vertical movement which has occurred in the appurtenant works, to-date.