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Check Valves

DFT®'s silent check valves are known around the world as the valve to use for preventing or eliminating Water Hammer problems.

Below are some key features and benefits of our check valves:

Designed To Prevent “Water Hammer.”
Designed To Open At Approximately 0.5 Psi Differential Pressure And Fully Open At 1.0 Psi Differential Pressure.
Can Be Installed In Any Position.
MSS SP 126-2000 Steel In-Line Spring-Assisted Center Guided Check Valves Standard.
Meets Or Exceeds MSS SP-61 Leakage Requirements.
Available With Soft Seats For Bubble-Tight Shutoff.
Dual Guided Stem.
Custom Sizing Available.
Pulse-Damping Design – PDC®
Liquids, Gas Or Steam.
Vertical Flow Up or Vertical Flow Down Installation
NACE Standards, MR0175/ISO 15156 Or MR0103.
Maintenance And Installation Guides Available For All DFT® In-Line Check Valves.
Quality Durabla® Check Valves

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Silent Check Valve Product Offerings

Threaded / Socket Weld Check Valves

DFT® offers a number of threaded valve options, including our Basic-Check®, Restrictor Check (RCV), SCV®, SCV-R®, and Vacuum Breaker models.

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Restrictor Check Valves

The Restrictor Check Valve ( RCV) is a spring-assisted, non-slam valve used for applications demanding higher cracking pressures.

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Vacuum Breaker Check Valves

Vacuum Breaker check valves protect against the collapse of pressure vessels, tanks, and rolls while preventing condensate backup when the system is off or the pressure is reduced.

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Contact DFT® Valves for more information!

Sanitary Check Valve

The DSV® sanitary check valves meet 3A standard 58-02 and are used in industries with strict hygiene codes. Available in both vertical and horizontal models.

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Wafer Check Valves

DFT®’s wafer options include ALC®, FBC®, TLW®, WLC®, and WLC® – CAST IRON check valves.

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Flanged Check Valves

DFT® flanged options include DLC®, Excalibur®, GLC®, GLC® – CAST IRON, and PDC® check valves.

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Butt Weld Check Valves

DFT® options include Excalibur®, Y-Calibur® , and BNC™ Check Valves.

View Excalibur® View Y-Calibur®

Nickel-Aluminum Bronze (NAB) Check Valves

DFT® models Excalibur® and GLC® are available in Nickel-Aluminum Bronze to withstand the harsh environments of salt and brackish water applications where corrosion resistance and marine life deterrents are needed.

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Nickel-Aluminum Bronze (NAB) Check Valves

Find My Check Valve

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Water Hammer Prevention

Find out more on what makes DFT® the check valve to prevent or eliminate water hammer.

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Our company is known as the Check Valve Doctor™, and for good reason: We specialize in preventing check valve problems and failures, including those caused by water hammer. DFT®’s in-line, spring-assisted check valves are specially designed to prevent water hammer and reverse flow. And since we offer custom sizing options, we can build check valves to your specific requirements for horizontal or vertical installations in liquid, gas, or steam applications. Even low-flow applications can be custom sized. Proper check valve sizing will optimize a system’s reliability, providing efficient service with maximum protection.

WATER HAMMER is the generation and effect of high-pressure shock waves (transients) in relatively incompressible fluids. Put simply, it is caused by the shock waves that are generated when a liquid is stopped abruptly in a pipe by an object, such as a valve disc. Common symptoms include noise, vibration, and hammering pipe sounds; these effects can then result in flange breakage, equipment damage, ruptured piping, and pipe support damage.

Whenever incompressible fluids exist in a piping system, the potential for water hammer exists. The risk of water hammer is particularly high when the velocity of the fluid is high, there is a large mass of fluid moving, and/or there are large elevation changes within the piping systems.

Since a swing check valve relies on gravity and/or fluid flow to help it close, flow reversal must occur before closure can begin. When the swing check finally does close, it abruptly stops the flow and causes a pressure surge, resulting in shock waves. These shock waves continue until the energy generated from this sudden action dissipates. The figure below displays typical pressure curves after closure of a check valve.

These high-pressure waves act against the piping and the valve, exerting very strong forces. This results in severe stress on the metal and vibrations within the system. If the system is not designed to withstand these high transient forces, the pipe can rupture and other components in the system, such as pumps and valves, may become be damaged.

These problems can be eliminated or greatly minimized by installing a spring-assisted silent check valve. Silent check valves do not rely on gravity or fluid flow for their closure. Instead, as the forward velocity of the fluid slows, the spring assist on the valve starts to close the disc. Due to the spring assist and the relatively short distance the disc must travel, by the time the forward velocity has decreased to zero, the valve disc has reached the seat, and the valve is closed.
With reverse flow eliminated, the forces necessary to produce water hammer on both the upstream and downstream sides of the valves are substantially reduced, as shown on the right side of the figure above.

Featured Resources

Check Valve Catalog

Check Valve Installation Rules & Guidelines

Understanding Water Hammer

View All Resources

Recent Blog Posts + See All

PDC<sup>®</sup> Valves vs. Piston Check Valves

PDC^® Valves vs. Piston Check Valves

Posted by DFT Valves on November 26, 2024 3:49 pm

Pulse-dampening check valves, or PDC® valves, are designed for installation on the discharge side of a gas or air reciprocating compressor and feature a pulse-dampening chamber. With this pulse-dampened design, during the momentary pressure and flow increases and reductions that occur with a reciprocating compressor’s cycles, the PDC® valve’s disc remains in the open position,… Read More

Webinar Q and A: Check Valve Applications for LNG Service

Posted by DFT Valves on November 7, 2024 8:55 pm

Following our webinar, “Check Valve Applications for LNG Service,” we’re sharing some of the questions from the audience along with our answers. In the webinar, we covered the fundamentals of LNG processes and the specific check valves used in liquefaction, storage, and transportation. We also discussed optimal valve placement and the importance of proper valve… Read More

Check Valves

Below are some key features and benefits of our check valves:

Silent Check Valve Product Offerings

Threaded / Socket Weld Check Valves

Restrictor Check Valves

Vacuum Breaker Check Valves

Sanitary Check Valve

Wafer Check Valves

Flanged Check Valves

Butt Weld Check Valves

Nickel-Aluminum Bronze (NAB) Check Valves

Water Hammer Prevention

Featured Resources

Check Valve Catalog

Check Valve Installation Rules & Guidelines

Understanding Water Hammer

Looking for more information?

Browse our resource library!

Recent Blog Posts + See All

PDC^® Valves vs. Piston Check Valves

Webinar Q and A: Check Valve Applications for LNG Service

Video Library

Types

Cut Sheets

Download ourCheck Valve Catalog

Download ourControl Valve Catalog

Check Valves

Below are some key features and benefits of our check valves:

Silent Check Valve Product Offerings

Threaded / Socket Weld Check Valves

Restrictor Check Valves

Vacuum Breaker Check Valves

Sanitary Check Valve

Wafer Check Valves

Flanged Check Valves

Butt Weld Check Valves

Nickel-Aluminum Bronze (NAB) Check Valves

Water Hammer Prevention

Featured Resources

Check Valve Catalog

Check Valve Installation Rules & Guidelines

Understanding Water Hammer

Looking for more information?

Browse our resource library!

Recent Blog Posts + See All

PDC® Valves vs. Piston Check Valves

Webinar Q and A: Check Valve Applications for LNG Service

Video Library

An Introduction to DFT®

DFT® DSV® Sanitary Check Valve

PDC® Check Valve for Reciprocating Compressors

What is Water Hammer?

Types

Cut Sheets

Download ourCheck Valve Catalog

Download ourControl Valve Catalog

PDC^® Valves vs. Piston Check Valves

An Introduction to DFT^®

DFT^® DSV^® Sanitary Check Valve

PDC^® Check Valve for Reciprocating Compressors