The disc coupon holder is designed to hold disc shaped coupons, positioning them flush with the pipe wall or projecting into the line The use of disc coupons has certain advantages over the strip coupon design, such as:
1) The coupon is placed flush with the pipe wall so that the environmental effects on the wall can be closely simulated.
2) When placed in the flush position, the coupon does not protrude into the line and interfere with pigging.
3) The coupon does not require orientation to product flow.