PDC^® Valves vs. Piston Check Valves

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, accommodating flow variations and eliminating chatter.

Allowing for either horizontal or vertical installation, these spring-assisted, nozzle-style check valves are used for air or gas and come in line sizes of 2″ to 26″ and ASME Classes 150 to 1500. As for material composition, the one-piece body of this flanged valve is available in either carbon steel or stainless steel, while the center guided trim is composed of stainless steel. You can choose between RF flanged ends or RTJ ends.

These high-performance silent check valves comply with API 6D, a specification set forth by the American Petroleum Institute to govern valve design, production, and testing for natural gas and petroleum applications. They also adhere to the standard ASME B16.10 face-to-face dimensions, as specified by the American Society of Mechanical Engineers.

Compared to piston check valves, PDC^® valves offer multiple advantages. Read on to learn more about these valve types and how they differ to determine which is the best option for your needs.

Piston Check Valves

Another variety of check valves is the piston check, which can be used in gas or liquid piping systems. This valve type functions by using a weighted piston, gravity, and backflow pressure. The piston rises up as a result of forward fluid flow within the valve, but when it experiences backflow pressure, spring force pushes the piston seal into the seat to prevent reverse flow.

Some differentiating factors are that with the fluctuations in pressure, such as from a reciprocating compressor, the constant hammering of the piston is not only quite noisy, but over time, the continuous wear the valve incurs can reduce its performance and ultimately lead to premature wear, constant maintenance, or even failure. The internal flow of the piston check is considered a tortuous path, which affects pressure drop. Additionally, the piston check has multiple pressure-retaining components (leak paths), whereas the PDC^® is a one-piece body.

DFT^®’s PDC^® Valves Are Built to Handle Reciprocating Compressor Discharge

At DFT^® Inc., we manufacture our PDC^® silent check valves for longer service life and quieter operation. The dampening chamber mitigates a compressor’s pulsed discharge for significant reductions in the wear and tear a piping system will experience. The valve’s unique shape offers the additional benefit of normalizing fluid flow exiting the check valve.

When you’re operating a piping system with an integrated reciprocating compressor, for example, this can cause high-frequency pressure cycling. An installed piston check valve would experience greater wear, impacting additional down-line systems, whereas the PDC^® valve offers better protection and more dependable functionality for your application and equipment.

Learn More About Our PDC^® Valves

Choosing PDC^® check valves from DFT^® over piston check valves can enhance the performance, reliability, and longevity of your piping system. This generally equates to a better return on your investment over the lifetime of the valve.

As a world-class manufacturer of control and check valves, DFT^® has the multi-industry experience, the resources, and the commitment to excellence and innovation required to produce high-quality valves that address the challenges of each of our customers. We offer an extensive catalog of silent check valve options for solving problems such as water hammer. In addition to our PDC^® model, we also have the following available:

• Threaded/socket weld check valves
• Wafer check valves
• Flanged check valves
• Butt weld check valves
• Sanitary check valves
• Restrictor check valves
• Vacuum breaker check valves
• Nickel-aluminum bronze (NAB) check valves

Whatever your application, DFT^® is here to help you find the right valve for your unique requirements. Contact our team today to learn more about the PDC^® silent check valve difference. You can also explore our PDC^® product page or view a 3D animation of the PDC^® pulse-dampening effect.