Tag Archives: mechanical seals

Across the broad spectrum of process industry applications today, fluid handling sealing systems perform a vital role in plant safety, maintaining pump efficiency, reliability, energy consumption, water usage and control of emissions to the environment. Often well hidden within the visible pumping equipment structure, mechanical seals operate 24/7 performing the critical function of static and dynamic sealing between the fixed pump housing and rotational drive shaft. From aqueous solutions to very abrasive slurries to highly volatile and hazardous fluids, mechanical seal technology continues to advance meeting the increasingly demanding application conditions and emission control standards required of users today.

Mechanical Seal Design
The most basic mechanical seal is comprised of a primary wear ring element fixed to the rotating shaft and a stationary opposing wear ring element that is fixed within the pump housing. Having precisely machined surfaces, these two wear components or seal faces are axially spring loaded together creating a seal interface. Dynamically, the wear faces operate on an extremely thin, highly engineered fluid film creating a stable, controlled operating environment between rubbing surfaces of the seal faces.

Maximum Sealing Safety and Reliability
Seal education and operator safety awareness training is of the highest priorities that the Fluid Sealing Association member companies promote. The FSA KnowledgeBase (fsaknowledgebase.org) shares design tools, best operating practices, and guidelines to meet government regulations using best available control technology, which emphasizes the importance of applying the right seal design for each given set of operating conditions. Seal selection based on all working conditions, fluid properties, equipment operating procedures and proven performance to industry standards like API-682 all must be considered and applied to achieve maximizing mean time between planned maintenance.

Environmental Responsibility
Recent advances in mechanical seal technology are playing a significant role in our collective responsibility to promote and achieve fluid control systems that meet the highest levels of environmental responsibility. The development of engineered seal face materials is lowering the coefficient of friction on seal faces thereby reducing power consumption, heat generation, and the associated the volume of cooling water required. Gas lubricated dry running dual seals that further minimize power consumption and fully isolate the process fluid from atmosphere are achieving near zero emissions to the atmosphere and the utilization of fluid dynamics modeling tools providing highly predictive behavior of seal interface conditions is optimizing performance on highly critical applications.

Unusual Mechanical Seal Applications

There are applications where the use of a mechanical seal would either not be considered or present major technical challenges. Here are some unusual examples of how mechanical seals can be applied to solve problematic sealing tasks.

LATEX
Liquid synthetic latex is an emulsion of polymer particles suspended in an aqueous solution. It is used in making coatings, glues and gloves and more.

Sealing latex has historically been a problem for mechanical seals because it solidifies when exposed to either heat or friction (shear). When latex is exposed to heat, water separates from the polymer particles leading to solidification or coagulation. A more challenging issue with sealing liquid latex is that when it enters the gap between the mechanical seal faces, it gets sheared which also leads to local coagulation.

Click here to read more.

Using IoT to Improve Mechanical Seal Reliability

The Internet of Things (IoT) is a phrase in the limelight. The concept of IoT is extremely appealing, in all forms, to commercial industry. The technology of IoT has been implemented in various industries globally and it is finally approaching the rotating equipment industry.

To fully explain and understand how IoT technology can be implemented to increase mechanical seal reliability, a description of maintenance philosophies is needed. There are three main types of maintenance philosophies in industry today: reactive, preventative and predictive. Currently in the pump industry, and more specifically with mechanical seals, most of the maintenance is either in the reactive or preventative ideologies.

Click here to read more.

A Guide to Elastomer Technology in Mechanical Seals

Elastomers (or rubbers) are a ubiquitous family of materials whose use stretches across nearly the entire range of mechanical seal designs. From plant-sourced natural rubber, so named by John Priestly in 1770 for its utility in rubbing away pencil graphite, to petroleum-sourced synthetic rubber first developed around the turn of the 20th century, elastomers and their properties are familiar but should not be overlooked – especially when dealing with mechanical seals.

Rubber seals come in a variety of profiles – O-rings, cup gaskets, bellows diaphragms, sealing/wiper lips and many others. They are classified as either static or dynamic and create positive pressure against surfaces to eliminate or control the leakage of liquids and/or gases while preventing the entrance of external contaminants such as dust and dirt.

Click here to read more.

Controlling the Seal Chamber Environment

Reducing the temperature in the seal chamber offers many benefits to the performance and reliability of a mechanical seal operating in hot service. This is one of the most effective ways to increase the vapor pressure margin and prevent the pumped fluid form flashing in the seal chamber or at the interface of the mechanical seal’s faces. Additionally lowering the seal chamber temperature also increases the fluid’s viscosity, providing a more stable fluid film at the interface of the seal faces.

One method of achieving a reduction in temperature is to circulate fluid form the seal chamber through a heat exchanger and return the cooled fluid back into the seal chamber. The heat exchanger is often referred to as a “seal cooler” since it is not part of the process, but just an auxiliary system component.

Click here to read more.

Mechanical Seals Division – FSA Annual Meeting 2017

The Mechanical Seals Division will be meeting on October 26 in Fort Worth, Texas. Discussion topics include upgrades to the Life Cycle Cost tool, including a new pump version. Updates will be given on the new KnowledgeBase and development of new content. This division is involved in activities in the STLE, BHRG, KCI Pump Summit, and the Turbomachinery Technical Conference. The FSA’s Technical Director, Henri Azibert, will lead a discussion on FSA and Hydraulic Institute joint webinars, Pump Summit presentations, Texas A&M Pump Symposium short courses, and opportunities to partner with API. Mr. Azibert will also present updates on other industry standards related to this division.

How Carbon Works in Mechanical Sealing

Mechanical face seals are a complex combination of materials and design that form a system whose prime objective is maintaining the integrity of the pumping system, keeping what is inside where it belongs and preventing contamination from the outside.

From the simplest design to the most complex, the system must operate across a multitude of conditions (and often beyond what the original design intended) in terms of speed, contact loads and environment. Every component in the system is a vital link contributing to the system’s success or failure.

Click here to read more.

Overview of Multiple Lip Seals

Multiple lip seals are commonly used in centrifugal pumps and positive displacement pumps. There are many variations, but one version that has been particularly effective is a triple lip seal arrangement. The key feature is the third outboard lip seal element, which can be used for several functions.

Sealed media can be compartmentalized, providing the opportunity to apply any of the API piping plans based on the type of media being sealed. For instance, it can serve as an excluder or a secondary seal in a quench gland design for media that crystallizes or hardens with exposure to ambient temperature and pressure. Unlike a mechanical face seal, there are no rotating parts, and all internal components are not just replaceable, but replaceable on-site by in-house or field maintenance staff.

Click here to read more.

FSA Introduces the KnowledgeBase Technical Reference

A key element of the mission statement for the Mechanical Seal division of the FSA states that we intend to be “…the primary source of technical information for our products and their application.” For many years, this objective was partially met through the publication and regular updating of the FSA Mechanical Seal Handbook.

For many who have relied on this FSA handbook for technical guidance on mechanical seals and support systems, changes in technology and user behaviors have caused their preferred source of reference material to shift from printed hardcopy materials to searchable online content. Therefore, we have spent the last few years converting FSA’s mechanical seal technical documentation into a format that is conducive to self-instruction by online users. This content has been developed, reviewed and vetted by representatives of the leading mechanical seals manufacturers and is considered to be representative of generally accepted best design practices for the industry.

Click here to read more.

The Fluid Sealing Association Launches Mechanical Seals KnowledgeBase

The Fluid Sealing Association (FSA) has announced the launch of their new website feature, KnowledgeBase. The content is developed and maintained by the members of the FSA Mechanical Seals Division as a service to manufacturers and users of mechanical seals. It can be accessed at www.fsaknowledgebase.org or through the FSA’s website at www.fluidsealing.com, and currently offers over 35 files of content and videos, each covering and explaining specific topics.

Safe, reliable and cost effective operation of mechanical seals and their support systems depend not only on the product design and materials of construction but also on the proper specification, application, and maintenance of the products. The FSA has created a digital knowledge base that provides easy navigation to key information to educate and inform users on these topics.

“The FSA KnowledgeBase is intended to be a vital source of highly reliable technical information regarding mechanical seals and support systems. Anyone who has an interest in improving their seal knowledge and remaining abreast of the latest mechanical seal industry best practices is encouraged to reference this as their primary source of information,” said Jason Ferris, Chair of the Mechanical Seals Division. “As the FSA seeks to continue to enhance the value provided by this tool to the mechanical seal user community, we encourage users to provide feedback on how the FSA KnowledgeBase can be improved by submitting input through the available link on the KnowledgeBase homepage.”

Click here to read more.