Abstract: A method is disclosed for determining physical properties of liquids, such as specific gravity or density. The method is performed through the use of a mainframe controller, a remote sensor, and two sets of dip tube assemblies, one for each of two measurement channels. The time at which a bubble is released by one of the dip tubes into a liquid and the size of the purge bubble are both controlled. By controlling the timing of bubble release, the pressure within a dip tube can b e measured after the system has been allowed to quiet down. If a pair of dip tubes is employed within the same vessel, the differential pressure can be measured when the pneumatic line pressure variations have reached steady state, that is after the gas flow into the dip tubes has been discontinued.

Abstract: A microprocessor based instrument is provided for measuring liquid level, specific gravity, or density.The instrument includes a mainframe controller, a remote sensor, and two sets of dip tube assemblies, one for each of two measurement channels. The instrument allows the operator to control both the time at which a bubble is released from one of the dip tubes into a liquid and also the size of the purge bubble which is released. By controlling the timing of bubble release, the pressure within a dip tube can be measured after the system has been allowed to quiet down. If a pair of dip tubes is employed within the same vessel, the differential pressure can be measured when the pneumatic line pressure variations have reached steady state, that is after the gas flow into the dip tubes has been discontinued.