Generally known as a relief valve, double check valves have fairly simple mechanics since their effectiveness is determined by the process flow, which means no other device is needed. They are usually attached to the pump head on the inlet and outlet lines of various types of fluid pipes in pumps and systems. Read More…

Leading Manufacturers
Check-All Valve Manufacturing Company
W. Des Moines,IA | 515-224-2301Our check valves are manufactured with the customer in mind. We believe in offering superior products and services every time. No matter whether you are looking for small or large valves, we can meet your every needs. It is our goal to offer excellent prices and service to each customer. Contact us to learn more today!

Plast-O-Matic Valves, Inc.
Cedar Grove, NJ | 973-256-3000Offering a full line of flow control products, Plast-O-Matic Valves ensures high quality by testing each of our valve products individually before shipment. We offer plastic check valves, PVC check valves, relief valves, ball check valves and more. We are committed to engineering excellence.

Ross Controls®
Troy, MI | 248-764-1800In 1920, Ross produced its first pneumatic control valves. Today we still make pneumatic valves plus large-port, high-flow check valves, pilot-operated check valves, high-flow relief valves, high-pressure valves, double valves and controls systems, plus safety products applicable to the fluid power industry. We are ISO 9001:2008 certified. For more information, visit our website!

Swagelok Company
Solon, OH | 440-349-5934Swagelok is a leader in the development and manufacturing of high-quality valve products. We offer a broad line of adjustable and fixed cracking pressure check valves to control back flow in general-service and high-purity applications. Our associates are singularly focused on how they can improve our customers’ experience through innovative products and services.

Tideflex® Technologies, div. of Red Valve Company
Carnegie, PA | 412-279-0044We manufacture traditional check valve and aeration products including all rubber check valves (outfall and specialty check valves) and inline check valves (housed inline, insertable inline and specialty inline). Our knowledgeable staff is ready and willing to help you find the products you need.

The body of the valve holds in place a ring-like element known as the seat, which extends from the inner walls toward the center-line of the pipe but does not fully close. A plugging mechanism, such as a piston or ball rests in the seat. Another plugging device is a swinging disk. When pressure is great enough and going in the desired direction, the stopper is lifted away from the seat, opening the gap to allow the process stream to flow freely. The reverse flow then pushes the plug back into the hole, creating an air tight seal that will not be opened again until forward flow pressure is greater than the back pressure. Since check valves allow the stream to flow in only one direction, the system stays clean. Specifically, double check valves consist of two spring check valves assembled in sequence, usually with a ball valve or gate valve at each end.
Double check valves have multiple valves working together for a few reasons. First, one check valve is still able to act even if the other is jammed open. Also, a more reliable seal is possible when one valve is closed, because this reduces the pressure differential across the other and stops leakage of any kind. Size varies among double check valves, as it does among all check valves.
Small valves may be so compact they are not noticeable, particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, which are partly there to test the double check valve periodically. This valve system mainly deals with keeping water clean and therefore requires consistent evaluation abilities for proper function. One industry utilizing double check valves is water treatment companies, but others use it often too.