API Standard 674 specifies the requirements for the pulsation study. This is recommended for many pump applications.
Reciprocating pumps (including diaphragm pumps, plunger pumps, and other positive displacement pumps) are used in many applications, including petroleum production facilities and refineries.
A pulsation and mechanical vibration study is often necessary for new or modified reciprocating pumps to avoid the following typical problems:
- excessive piping vibration and piping failures;
- pressure pulsation-induced cavitation in liquid pump fluid ends and suction manifolds, damaging the pump and reducing reliability;
- undesired opening of PSV due to pulsations; and
- improper pump valve dynamics leading to poor valve life and reduced flow capacity.
- Assess the magnitude of pressure pulsations and unbalanced shaking forces
- Recommend a pulsation solution that meets API 674 guidelines and BETA guidelines
- Conduct a mechanical review analysis of the piping layout and support using standard tables and spreadsheet calculations
- An optional finite element (FE) mechanical analysis of the piping system can be conducted to avoid coincidence between mechanical natural frequencies (MNFs) and dynamic forces occurring at multiples of plunger passing frequency.
- This simple guide is useful to determine the pulsation study scope and other application requirements.
- Contact BETA for other application questions, including Valve Dynamic Assessments and troubleshooting.
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Features of BETA's Pulsation Studies
- Assessment of pressure pulsations and unbalanced shaking forces
- Recommended pulsation control solutions
- Assessment of static and total pressure drop, and compare to guideline
- Assessment of all operating conditions
- Use of BETA’s time domain software to accurately calculate pressure pulsations through the system
- The following considerations must be evaluated for improved reliability:
- Cavitation inside pump chambers and in suction lines
- Pressure and vibration at relief valves (per guidelines)
- Pipe stresses
- Upset conditions (e.g., plunger valve failure, dampener failure)
- Optional: Detailed mechanical (FE) analysis of the system to avoid high vibration due to resonance, normal shaking forces, and forces produced in upset conditions
The analysis does not assess vibration in the skid and/or foundation. These assessments are provided by separate analyses.
- Cost effective solution to avoid pulsation related problems
- Pulsation control across the entire range of the pump operation. NOTE: Many pulsation control designs neglect this important point.
- Improved reliability, availability, efficiency and safety by avoiding piping and vessel vibration failures
- Reduced maintenance and operating costs
BETA is the global leader in pulsation analysis because of these factors:
- Responsive application advice and ongoing customer service
- Most advanced acoustical/mechanical modeling software on the market
- Timely recommendations
- Field validated pulsation modeling, which means our results can be trusted.
Case Study Articles
Poor pump design considerations can limit operations. This case study, printed in CompressorTech2 magazine's April 2012 PumpTech section, discusses a reciprocating diaphragm metering pump installation was limited to 25% of rated flow capacity.
> Poor Pump Design Considerations (PDF)
> Integrity of Pulsation Dampeners in Liquid Systems (PDF)
> Reciprocating Pump Design Flaws (PDF)