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Magnus Gustafsson has over 10 years experience in the design and analysis of mechanical components and systems in the Petrochemical and Railway industries. His experience includes Fitness-for-service assessments and design support of pressurized equipment including elastic-plastic Finite Element Analysis, transient heat transfer analysis, creep, high-and low cycle fatigue, fracture mechanics, fluid surge and piping flexibility analysis.

Why do Clamped Connections With Metallic Seals Sometimes Leak?

cover-pipe-clamp
Clamp connections with metallic seals can offer superior joint integrity over traditional flanged connections but caution must be exercised regarding the service conditions, especially when cyclic thermal loading is present. This blog post highlights aspects of a clamp connection analysis performed by Becht Engineering. The client had observed significant loss of bolt preload at several clamp connections installed in a refinery process unit where the fluid temperature regularly fluctuated by 700 o F. The client attempted to counteract the bolt preload loss by re-torqueing any bolts that showed a torque reduction from the initially applied torque only to find that, after a period during which thermal cycles occurred, the preload was again reduced. A typical clamp arrangement is seen in Figure 1 (with parts labeled). After reviewing the installation and service conditions, it was hypothesized that the cause of the bolt preload loss could be the differential thermal growth of the...
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Magnus Gustafsson

Re: Belleville Springs

Fran, No, we did not look at Belleville washers as part of this work. I do expect they would help, but I understand the preferred... Read More
Thursday, 04 April 2019 14:18
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Fitness-For-Service API 579-1/ASME FFS-1: Substantive Changes to the 2016 Edition

Fitness-For-Service API 579-1/ASME FFS-1: Substantive Changes to the 2016 Edition
Contributing Authors: Eileen Chant, Greg Epremian, Ranjan Nadarajah, Mark Stonehouse  Summarized herein are the substantial changes to API 579-1/ASME FFS-1, Fitness for Service , that were incorporated in the 2016 edition, as reviewed by Becht Fitness for Service experts. API 579-1/ASME FFS-1 is a Standard jointly published by API and ASME.  The purpose of the document is to provide a consensus of methods to quantitatively evaluate commonly observed damage to in-service pressure equipment.  Since it was first issued by API in 2000, this Fitness-For-Service standard has been used worldwide as a means of evaluating whether pressure equipment was fit for continued service, and in many cases, for how long.  This standard has been used to avoid costly and unnecessary unplanned outages, while maintaining safe and reliable equipment.  The Second Edition was released in 2007, followed by the most current release of the document in June of 2016.  In addition to the...
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Piping Settlement Screening Tool

Piping Settlement Screening Tool
Settlement of a pipe support foundation is usually not a big deal to assess. A local piping flexibility model will reveal if the settled support keeps the pipe bending stresses within the allowable codes and, if the bending stresses are unacceptable, modifying the support and monitor periodically for further settlement is normally a quite manageable task. However, if settlement is occurring site-wide at a large site due to errors in the pre-construction soil surveys, the problem quickly becomes unmanageable. A client recently approached Becht Engineering with a request to develop a screening tool. A tool that inspectors at such a site can easily use in the field to quickly screen pipe circuits subjected to support settlement. The stated objective was to determine which circuits are acceptable without further study based on conservative criteria requiring detailed follow-up, i.e. piping flexibility analysis. This blog supplies an overview of the bases for this tool....
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Estimating Creep Life of Fluid Catalytic Cracker Internals Using FEA

Estimating Creep Life of Fluid Catalytic Cracker Internals Using FEA
How long will the cyclone system in a Cat Cracker reactor or regenerator last? Cyclones systems in Fluidized Catalytic Cracker units (FCC) are typically designed to a creep allowable stress, where the stress field at various locations of the system has been determined by linear elastic analysis. The basic allowable stress for such internal structures (not on the pressure boundary) is commonly taken from B31.3 or API RP-530, where the allowable stress is dependent on the design life, often 100,000 hours, approximately 11 years. Such analyses may take into account stress classification to give an allowance for elevated stresses of secondary nature (self-equalizing stresses), but this practice often under-estimates the actual stress redistribution that takes place as the structure permanently deforms from creep. Once the time in operation has surpassed the design life, it would seem that the creep life of the structure should be consumed and that the cyclone system...
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