Archive: Sep 2014

Watch DFT Valves’ ALC® Axial Flow Check Valve in Action

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Check valves are instrumental for regulating fluid flow within a given valve system. When properly chosen and installed, check valves are meant to operate seamlessly throughout their design life; improper check valves can lead to harmful complications—such as water hammer.

Axial Flow Check Valve Video

Water hammer is one of the most common problems befalling check valves. Simply put, water hammer is the generation of shock waves that occur when a liquid comes to a sudden stop inside a pipe. These high-pressure shock waves persist until the energy of the surge dissipates; during that time, shock waves can cause serious damage to pipe lines, joint gaskets, pressure gauges, and other components.

Valves that close on reversing flow and back pressure are major contributors of water hammer; these valves include swing check valves, tilting discs checks, and double door check valves. Water hammer can lead to poor productivity due to failures, so it’s vital to use check valves designed to combat this issue.

DFT Valves’ ALC® axial flow check valves are an ideal choice to reduce the effects of water hammer. The DFT Valves team created a short video to demonstrate how beneficial this check valve can be to your system.

DFT Axial Flow vs. Double Door Check Valve

In this video, we demonstrate the difference between our ALC® check valve and a double door check valve on the psi of a pump valve application. This specific application is 15 psi, and the double door valve causes a pressure spike that nearly reaches 60 psi. Due to this pressure imbalance, we replaced the double door valve with our axial flow check valve.

Once the ALC® check valve is installed, you can immediately notice the pressure stabilize within the pump’s system. The psi goes from zero, back up to 15 without any pressure spike as the ALC® valve cycles.

Benefits of the ALC® Check Valve

The DFT ALC® valve is designed specifically to prevent water hammer and reverse flow. Lightweight and compact, these valves can fit between mating flanges with ease. ALC® valves are useful for a variety of applications that involve liquids, gases, or vapors. Other benefits of these valves include:

  • Simple to maintain
  • Can be installed horizontally or vertically
  • Body material can be carbon, stainless steel, or other materials.
  • Custom sizes can be made to your specifications
  • Meets several industry codes and standards, including ANSI, MSS, and ASTM

To learn more about choosing a DFT check valve that is best suited for your application, contact us today.

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DFT Model PDC® Solves Air Compressor Problems

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Inside their control valve test and research facility, a major valve manufacturer was using two reciprocating air compressors that were designed to run until the stored air pressure in the extremely large volume tanks reached a set point.

They would then shut off for anywhere from several minutes to several hours, depending on demand. During the shut-off intervals, the wafer-style swing check valves on the discharge side were leaking, tripping the relief valves and threatening to over pressurize system components.

The Use of DFT Technology

4 DFT model PDC check valve in use

On several occasions, the continual pounding of the valve seats resulted in total failure, which caused the system to blow the intermediate stage safety relief valve and totally shut down.

Despite being a valve manufacturer themselves, they recognized that our insight into check valve technology would help them find the best way to address shut-off performance and longevity. Our solution was to replace the valves in both the 200 hp/1000 psig and 400 hp/400 psig air compressors with DFT model PDC® check valves.

 

Preventing System Pressure from Bleeding Back

Designed specifically for reciprocating equipment, these silent, non-slam check valves prevented system pressures from bleeding back into the compressor when the machines were off as well eliminated the unacceptable reverse flow leakage. The machines now run in optimal states and are no longer susceptible to shut down.

If you are interested in learning more about this project, or if you have a situation that would benefit from our insight into valve technologies, contact us today.