An ASME U-Stamp pulsation dampener for an iron plant

The challenge

An iron production plant in Trinidad and Tobago runs a reciprocating compressor in its process. By their nature, reciprocating compressors deliver gas in pulses rather than a steady flow, and those pressure pulsations travel into the connected piping, where, untreated, they drive vibration, fatigue and noise, and can shorten the life of the compressor and the line it feeds.

The plant needed a pulsation dampener large enough to absorb those pulses and present a smooth flow to the downstream system. Because it is a pressure vessel in a demanding industrial process, it had to be designed and built to a recognised pressure-vessel code and carry the corresponding certification, specifically ASME VIII Division 1 with the U-Stamp designator. It also had to be a physically large vessel, 1,800 mm in diameter and 7,000 mm long, and be fabricated, code-stamped and shipped complete to a site in the Caribbean.

Our approach & engineering

Axces designed and manufactured the dampener as a code-stamped pressure vessel from the outset, sizing the internal volume to absorb the compressor’s pulsations while meeting the requirements of the ASME code at every stage: from the design calculation, through material traceability and welding, to the final inspection and stamping.

Design to ASME VIII Division 1, U-Stamp

The vessel was designed and manufactured to ASME VIII Division 1, the code for the design and fabrication of pressure vessels, and carries the U-Stamp designator, the mark confirming the vessel was built and inspected under a certified ASME quality programme. The design conditions are 3 bar and 150 °C. Code-stamping the vessel gives the plant an internationally recognised basis for its integrity, its inspection history and its place in the site’s mechanical-integrity records.

Sizing for pulsation control

At 1,800 mm in diameter and 7,000 mm long, the dampener provides the internal volume needed to absorb the pressure pulses from the reciprocating compressor and smooth the flow into the downstream piping, reducing the vibration, fatigue loading and noise those pulsations would otherwise carry into the line.

• Designed and manufactured to ASME VIII Division 1, U-Stamp
• 1,800 mm diameter × 7,000 mm long
• Design conditions 3 bar at 150 °C
• Internal volume sized to absorb reciprocating-compressor pulsation
• Full material traceability, welding and inspection records under a certified ASME programme

Scope of supply

Axces delivered the dampener as a complete, code-stamped pressure vessel:

• 1 × pulsation dampener, Ø1,800 mm × 7,000 mm, ASME VIII Div. 1, U-Stamp
• Design calculation and documentation to the ASME code
• Material certification and full traceability
• Welding and non-destructive examination records
• ASME nameplate with U-Stamp designator, ready for installation in Trinidad and Tobago

Results

The plant received a large, internationally code-stamped pulsation dampener, engineered to smooth its reciprocating compressor’s output and protect the downstream piping, delivered complete to a Caribbean site with the full ASME documentation package behind it.

• Code-stamped to ASME VIII Division 1 with the U-Stamp designator
• 1,800 mm × 7,000 mm vessel rated for 3 bar at 150 °C
• Pulsation absorbed to reduce vibration, fatigue and noise in the downstream line
• Complete ASME documentation: calculation, material traceability, weld and inspection records

Related reading

• Pulsation dampeners: protecting piping from reciprocating compressor pulsation: why reciprocating compressors create pulsation, the damage it causes, and how dampeners protect the piping
• Combined pressure and noise control: when one device must do both: how pulsation dampeners and vent silencers solve pressure and acoustic problems together
• Pressure vessel design and certification: PED 2014/68/EU essentials: the EU pressure-equipment framework, the counterpart to the ASME code this vessel was built to