PULSE-PHASE METER FOR MEASUREMENT OF THICKNESS OF LAYERS OF DIFFERENT LIQUIDS AND THEIR RELATIVE CHANGE AT ENHANCED ACCURACY Russian patent published in 2002 - IPC

FIELD: monitoring and measuring units for measurement of thickness of layers of different liquids by their electrophysical properties; automated control systems of technological processes. SUBSTANCE: proposed meter is built on base of transceiving module with antenna system, analog-to-digital converter and on-line storage units and computer controlling radiation and reception modes (radiation frequency and level of reflected signal) at radiation of liquid medium by radio frequency pulses at phase shift set by controllable phase shifter 0 or π/2 every other sounding period at one of frequencies of working frequency band of discretely-controlled microwave oscillator. Rf pulses reflected from interface of liquid layers are mixed with continuous rf signal of the same oscillator at phase detector at whose output quadrature components of signal are separated at every other period and are converted into digital form and are recorded in buffer on-line storage. Data of buffer on-line storage are entered into computer. Meter performs search and storage of time delays of maxima of signals reflected from each level of interface maintaining equality of amplitudes of quadrature components of signals at extreme points of working frequency band of microwave oscillator and changing frequency of radiation from lowest to highest magnitudes, as well as maintaining level of reflected signal within dynamic range of analog-to-digital converter. Phase transitions of received signal is calculated through magnitude -45 deg. by each stored time delay. Magnitude of time delay of quadrature signals relative to signal infiltrated to receiver input through circulator is determined by number of phase transitions of received signal and by difference of carrier frequencies at extreme positions of working band; number of liquid layers and their thickness are determined by time delays. Relative change of thickness of layers of different liquid is determined by stored magnitudes of time delays of maxima of reflected signals which are maintained by regular adjustment of radiation frequency so that phases of received quadrature signals should be equal to -45 deg.; relative change of thickness of layers is calculated by magnitude of change of radiation frequency for each level of liquid. EFFECT: enhanced accuracy of measurements; low cost of method. 12 cl, 8 dwg