A.Y. McDonald Water Works Check Valves and Backflow Prevention

A.Y. McDonald Water Works Check Valves and Backflow Prevention

Protecting our drinking water supply is a top priority for water providers. Therefore, as the industry continues to improve, so do the products that transfer this resource from the water supply to the water meter. One of the ways in which this is achieved is through backflow prevention.

In relation to the water and plumbing system, backflow is the unwanted flow of water in the reverse direction. This can lead to the contamination of potable water supplies with foul water. Backflow may occur from one of two reasons:

1. Back pressure: The result of a higher pressure in the system than in its supply. For example, if the system pressure has been increased by some means. This can happen in unvented heating systems where thermal expansion increases the pressure.
2. Back siphonage: The result of supply pressure being lowered below that of the system. This can happen when a supply is interrupted or drained down.

One solution for backflow prevention is the installation of a check valve after the water meter. A check valve is one of the few self-automated valves that does not require assistance to open and close. It is sometimes referred to as a ‘one-way’ valve because the fluid is allowed to move in one direction only. The check valve will be marked with an arrow indicating fluid flow direction. The construction of the check valve is normally simple with only a few components such as the body, seat, disk, and cover. The valve is considered flow sensitive and relies on the fluid to open and close. The internal disc allows flow to pass forward, which opens the valve. The disc begins closing the valve as forward flow decreases or is reversed (depending on the design). There may be other items such as a stem, hinge pin, disc arm, spring, and ball (also depending on the design).

Although there are many types of check valves in use today, the most common are the spring assisted in-line and angle, single, and double check valve. Other common check valve types include ball, dual plate or double-door, piston or lift, and swing or flapper. Common materials used are brass, stainless-steel, steel, and PVC. A.Y. McDonald water work valves are constructed of brass and include a variety of configurations and applications. Below is an overview of our water works check valve product options:

The backflow of water and the steps to prevent it is a hot topic in the water industry. Thankfully, check valves serve as a possible solution due to their ability to the unique design of the one-way valve. To learn more about water works check valves and how to order an A.Y. McDonald water works check valve product option, take the ‘A.Y. McDonald Water Works Check Valves’ AYU course, call our customer service department at 1-800-292-2737 or fill out a contact us form on our aymcdonald.com website.