What is a coupon in water treatment?

What is Corrosion Monitoring and What Are Its Objectives?

Corrosion monitoring is a process performed to identify, access, and analyze the corrosion behavior of a system. Any corrosion monitoring is performed with two main objectives:

• To understand the operational condition of the equipment
• To understand the effect of different variables such as temperature, pH, water quality, and chemical treatment on different water systems

Using the right corrosion monitoring system enables users to meet these objectives, as well as achieve the following results:

• Identify the corrosion-related problems at different parts of the equipment and mitigate them effectively.
• Improve the life span of equipment, its components, structures, and process units.
• Minimize operating costs of the plant.
• Predict the maintenance needs of the equipment and design an effective maintenance program.

What Are Corrosion Coupon Racks and Corrosion Coupons?

The corrosion coupons are standard pre-weighed metal strips that are mounted on coupon racks. The coupon racks comprise several pipes and they are mainly used to estimate the metal corrosion rate of water systems like coolers. The coupons are weighed and exposed to water. Their weight is checked at regular intervals such as 60, 90, and 120 days to identify the rate of corrosion. They are available in various materials. At Cannon Water, we provide various types of coupons. You can choose between copper corrosion coupon, brass corrosion coupon, and carbon steel coupons.

Features of Corrosion Racks Provided by Cannon Water

The following features of corrosion coupon racks have contributed to their popularity with our clients.

• We provide standard coupon racks, which can be customized with one to six corrosion coupon holders. They come with inlet/outlet isolation valves.
• They can be equipped with PVC, CPVC, carbon steel, and stainless steel pipes of 3/4", and 1" diameter.
  • The PVC pipes are suited for most applications.
  • CPVC pipes are suited for applications that require moderately high temperatures.
  • Carbon steel and stainless steel pipes are ideal for applications where they would be exposed to high temperatures.
• The rack features a durable mounting frame and stainless steel safety chains that can hold the coupons in place.
• Our coupon racks are easy to install and feature quick-connect sample points.
• The racks can be customized with various optional features such as flow meters, Y-strainers, flow control valves, sample valves, and so on. The prices may vary depending on the customization.

Special Tips to Improve the Performance of Corrosion Racks

Corrosion coupon racks offer results based on different variables. Thus, it is important to install the rack such that it produces the most accurate results. The following pointers will be helpful in this case.

• Avoid touching the coupons with bare hands as any chemical or oil present on your palms may accelerate corrosion and alter the results.
• Ensure to maintain the flow of the rack at 3-5 feet per second. This is because flow rates below 3 will make the particulates rest on the coupons and the ones above it may erode metals like brass and copper.
• Arrange the coupons on the rack such that less noble materials such as carbon steel are mounted upstream followed by noble materials of higher-order like copper towards the downstream. This helps prevent copper ions from plating on the iron coupons and accelerating artificial corrosion rates.
• Avoid touching the coupons when they are in use and do not attempt to remove them until the testing period ends. This is because exposure to air may accelerate their corrosion rate.

If you have been facing the problem of corrosion in your aging cooling tower or water systems, then this coupon rack is the best option. Are you facing any other water treatment problems? Being at the forefront of water treatment and wastewater treatment technologies for a long time, we understand what solution works best for any situation. Feel free to discuss your water treatment requirements with our experts. We would be happy to help you.

Source: Chemtex

What are corrosion coupons?

A corrosion coupon rack is a simple corrosion monitoring device that uses corrosion coupons, which are strips of metal that match the metals in the system where they are installed. The initial weight of each coupon is carefully measured and logged. They are then installed in the corrosion coupon rack where system water is allowed to pass over the metals for between 90-100 days. After the test period expires, they are pulled out, sent to a lab, and weighed. The difference in weight will represent the level of corrosion in the system.

Why is a corrosion coupon rack needed?

Regular corrosion coupon analysis provides valuable feedback on the effectiveness of a water treatment program. When corrosion inhibitors are maintained at prescribed dosages one should expect corrosion results to meet or exceed industry standards.

Tips for installation and maximum performance.

Several factors should be kept in mind for performing an accurate test.

• Placement is important. Placing the rack behind a heat source increases corrosion, whereas placing the rack after a cooling tower leads to lower corrosion rates.

• Avoid cooling system tests in Spring and Fall, as a consistent flow is needed for the most accurate results.

• Flow rate, direction, and spacing all impact the outcome of the study.

• Any contamination to your system, such as leaks, oils on from touching the coupons with your hands, or other contributors will also bias your test results.

What do the results mean?

Boland provides a corrosion coupon report for each coupon. Reports classify the corrosion levels as poor, moderate, good, or excellent based on industry standards. Results can help determine if changes in system chemistry need to be made to prevent further corrosion.

Expensive equipment repairs or replacement can be easily prevented when corrosion rates are identified quickly. Coupon racks are an inexpensive way to measure and verify the overall effectiveness of water treatment inhibitors.

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