Pulsation dampeners are typically used to attenuate fluid pulsations produced by triplex (3 cylinder) positive displacement (PD) pumps. These pumps are commonly used in high pressure nuclear applications due to their high degree of reliability.
The tradeoffs for this reliability include:
- Pressure pulsations (spikes)
- Pressure relief valves activating
- Possible acoustic issues with the surrounding pipe systems
For years, to attenuate the pulsations the industry has used a small canister with a pressurized ladder on the inside. Unfortunately, there have been numerous incidents with the bladders losing pressure and occasionally disintegrating into the fluid path and contaminating it.
The preferred design is spherical vessel that receives water from the pump and due to proprietary internal geometry (not shown above) accelerates the flow and imposes an axial spin to the stream. This flow pattern substantially reduces the amplitude of the pressure-pulses leaving the dampener. The water in the dampener acts similarly as a fly-wheel to absorb and dampen pressure pulses.
Nuccorp’s solution has no moving parts or air-bladders. In fact, Nuccorp uses patent pending and proprietary technology to deliver the only Pulsation Dampener that is acoustically adjustable.
Nuccorp’s Pulsaltion Dampener
(Internals are proprietary)
Old Style Bladder Dampener
FEA and Acoustic Modeling
Extensive FEA modeling and knowledge of acoustics are combined to ensure that the pulsations and accousical signals produced by the Tripeax pump are adjusted to ensure they do not harm the system pipes due to resonant frequencies, harmonics and pressure spikes.
Actual before and after system data shows reduction in max pressure.
Modeling and extensive field testing has been performed to verify the models
- The tests tuning achieved a resonant frequency corresponding to a pump speed around 359 rpm.
- Further high pulsation amplitudes were found near 395 rpm, at which the system response was dominated by the second harmonic of the pump frequency.
- The test was used to determine the attenuation performance of the dampener in five tests at pressures between 350 psig and 2565 psig and temperatures of 100°F and 170°F.
- Amplitudes generally were attenuated by a factor of 20 or more at the dampener outlet.
- The pulsations with the dampener in-service were small, never
- exceeding 47.3 psi peak-to-peak
Performance is critical and there is zero room for error. To assure performance, an acoustically equivalent customer pipe system was build under laboratory conditions and Nuccorp’s Pulsation Dampener was tested. Pulsation attenuation and the acoustical response to the output frequencies were observed and measured on the test dampener before it was put into production.
Nuccorp’s Bladderless Pulsation Dampeners (BPDs) are available though our industry partner NuSource, LLC. A one-page brochure can be found here.
NuSource pulls together Nuccorp’s BPD design, acoustical analysis and licensing, their ASME N-Stamp fabrication ability and the testing procedures designed by MPR to deliver maintenance-free, trouble-free pulsation dampening that will far exceed the useful life of the plant.