Accurate monitoring of corrosion rates in pipe line is critical when viewed in terms of the maintenance and repair costs associated with corrosion and material failure. Test coupons provide a cheaper means of on-line monitoring that will allow you to effectively measure the corrosion rate within your system. By observing the corrosion rate of an exposed coupon, valuable information can be provided regarding the material's life expectancy.
Crystal can make coupons in sizes, shapes, or materials of customer needs. Coupons can be stencilled and sequence numbers for proper identification. Mill test report, identifying element compositions of materials used, are provided on all orders.
Due to its large surface area, the strip coupon provides the most area of all coupon types on which corrosion can develop and be readily observed. The strip coupon also gives more accurate results of weight loss because it has a larger mass than other coupons.
The disc coupon can most closely simulate the conditions that are occurring on the pipe wall. Unlike other coupons, they can be flush mounted. This gives them the advantage of not interfering with any pigging that may be done on the line. The disc coupon is mounted on the coupon holder in a plane at right angles to the holder stem, thereby avoiding any necessity to orientate them with the system flow. Multiple disc coupon holders are very popular in lines which carry more than one phase, since a disc coupon can be positioned in each of the phases.
Rod coupons are generally used where a longer exposure time is required. Since six coupons can be mounted on a single holder, the insertion and removal of the coupons is staggered, with only two coupons being removed at any one time. This allows the operator to collect data from the coupons regularly, but at shorter intervals than would otherwise be possible.