Research on the Structure of Coupons in the Multi-Function Cathodic Protection Test Probe

For the multi-function cathodic protection test probe, the structure and relative displacement between coupons is always a crucial problem. In this paper, the effect of the polarized coupon on the potential of the corrosion coupon and stray current interference were studied when coupons were set in two different arrangements. The results showed that, the smaller the area of the polarized coupon was relative to the corrosion coupon or the larger the space between coupons was, the stronger the performance of anti-interference of test probe by itself or the stray current was when in parallel arrangement, and it was reasonable that the area of the coupon from pipeline with coating of good quality was 1cm2; when in concentric arrangement, the geometric center of the coupon had the best performance of anti-interference, thus, with regard to pipeline with coating of poor quality but requiring coupons of larger area to simulate the holiday, the polarized coupon and the corrosion coupon could be made as circular ring type and be arranged concentrically and horizontally in the bottom of the probe of which the center was the reference electrode.