DETERMINATION OF DEPOSITION THICKNESS AT INNER SIDE OF PIPES BY EDDY CURRENT METHOD AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2013 - IPC G01N27/72 G01B7/06 

FIELD: electrical engineering.

SUBSTANCE: determination for deposition of thickness at the inner side of pipes by eddy current method by means of attachable sensor through which circular transmitting coil alternative current is passed and which measuring coil is connected to signal processing block to transmitting coil with radius R_t selected from, the ratio $$3\left({\delta }_m^n+{\delta }_d^m\right)>R_t>\mathrm{1,0}\left({\delta }_m^n+{\delta }_d^m\right),$$ where and are rated and maximum values of thickness respectively for pipe walls and deposition; rectangular current pulses are supplied with period $$T_t\ge 3R_t{\mu }_0\left({\delta }_m^n{\sigma }_m^n+{\delta }_d^m{\sigma }_d^m\right),$$ where and are rated and maximum values of specific conductance respectively for metal and deposition; parameters of deposition are assessed by amplitude-time characteristic of the measuring coil response, at that within time period $$t=\left(\mathrm{0,03}÷\mathrm{0,3}\right)R_t{\delta }_m^n{\sigma }_m^n{\mu }_0$$ thickness δ_m and conductance σ_m of the pipe metal is measured and within interval $$t=\left(\mathrm{0,4}÷\mathrm{0,6}\right)R_t{\mu }_0\left({\delta }_m^n{\sigma }_m^n+{\delta }_d^m{\sigma }_d^m\right)$$ δ_d and σ_d parameters are defined for deposition with consideration of pre-determined values δ_m and σ_m. The device for its method implementation is also suggested.

EFFECT: ability to control deposits without use of calibration samples and to define structural condition of deposition, which provides control of deposition of different types.

2 cl, 7 dwg