Nnmechanical seal failure analysis pdf

Failure modes of a mechanical seal can be identified by three main causes of failure. The failure mode of mechanical seals and the various cause events to help in taking appropriate steps to improve sealing reliability are discussed by singh et al. The first step in a seal failure analysis is to determine what, exactly, constitutes a failure. The appearance of the seal can provide significant insight into potential causes of. Analysis of a mechanical seal failure in maintenance organizations where time and cost of repair are crucial elements, it is of paramount importance for a reliability engineer to determine swiftly and accurately the failure modes and root causes underlying a particular issue to avoid further machinery breakdowns. The shaft seal is exposed to widely varying operating conditions. This seal operated in a very dirty environment and the mating ring bore does not appear to be concentric with the shaft. The wrong lubrication was used as indicated by the transfer of carbon to the mating ring. Pdf on jan 1, 2012, jasbir singh and others published failure mode analysis of mechanical seals find, read and cite all the research you need on researchgate. Damage to the seal from the gap between the sliding surface and housing. An analysis of common causes of major losses in the. Influence of randomness in rubber materials parameters. In sealing structures, failure of the rubber oring seal may lead to catastrophic.

After this general analysis, the four identified critical failure modes are analyzed in more detail and the failure mechanisms are determined. All these studies have basically regarded the traditional bolted flange joints. Detailed information is required to make a failure analysis of a damaged shaft seal and subsequently prevent new failures. Failure analysis and troubleshooting mechanical seals and. The rubber drive ring was forced up into the seal the seal came apart upon final installation. Mechanism based failure analysis university of twente research.

The weibull distribution is used to fit the failure data of mechanical seal and build. It is to be noted that same seal never displayed this type of failure mode prior to introduction of high pressure external seal flush. This course will introduce root cause analysis rca, function evaluation, and mechanism identification in the context of mechanical seal failure investigations. Introduction to failures failure of the mechanical shaft seal is the most common cause of pump downtime. Vpacking female adapter ring showing clear signs of extrusion. Sealing failure analysis on vshaped sealing rings of an. All other losses simply classed as non mechanical integrity failure secondly, all mechanical integrity failure losses then classified. This section describes the most common failure modes seen. Failure of mechanical shaft seals the knowledge link.

Any company buying mechanical seals from a reliable vendor has the right to expect a sensible failure analysis on the majority of their seal failures. Failure analysis is not always straightforward and exact, but it does follow a systematic approach, so it. Stuffing box pressure at nde increased form 14 bar to 17 bar. Analysis of a mechanical seal failure reliabilityweb. Case studies in engineering failure analysis journal. This article presents a study on failure analysis of mechanical face seals using reliability tools such as the weibull and weibayes techniques. The weibull tool is used when a reasonable number of failure data are available, whereas the weibayes approach is employed when the failure data are scarce or nonexistent. The analysis of an oring or seal failure includes many factors, including the environment, the seal design and the elastomer itself. Sometimes operating conditions change to become quite different from the specific conditions for which the seal was intended. As per the seal vendor spec, the max pressure limit for bellows is 15 bar, which. In addition, these same techniques will be applied to monitoring opportunities for mechanical seal piping plans in operations. Parameters changed after introduction of plan 32 were. Click here for full pdf version of this article includes all graphs, charts, tables and author information.