api mechanical seal manufacturer

The Stein Seal® Company has developed API1 STANDARD 682 seals for the oil and gas industry. Stein Seal® has designed, manufactured and tested the seals according to the rigorous API Standard 682 test protocols. In general, these are balanced seals with cartridge construction. These seals are classified in to Types, Category, Arrangements and Configurations. The seals are designed and tested to operate continuously for 25,000 hours without need for replacements.

Type A seal is a balanced, internally-mounted, cartridge design, pusher seal with multiple springs. Secondary sealing elements are elastomeric O-rings.

Category 1 are intended for use in non API 610 pump seal chambers, meeting the dimensional requirements of ASME B 73.1 and ASME B73.2 seal chamber dimensions and their application is limited to seal chamber temperatures from -40°F to 500°F (-40°C ~ 260°C) and gauge pressures up to 300 psi (2 MPa / 20 bar).

Category 2 are intended for use in API 610 pump seal chambers dimensional requirements. Their application is limited to seal chamber temperatures from -40°F to 750°F (-40°C ~ 400°C) and gauge pressures up to 600 psi (4 MPa / 40 bar).

Category 3 provides the most rigorously tested and documented seal design. They meet the seal chamber envelope requirements of API 610 (or equal). Their application is limited to seal chamber temperatures from -40°F to 750°F (-40°C ~ 400°C) and gauge pressures up to 600 psi (4 MPa / 40 bar).

Arrangement 2 seals having two seals per cartridge assembly, utilizing the externally supplied buffer fluid at a pressure less than the seal chamber pressure.

Arrangement 3 seals having two seals per cartridge assembly, utilizing the externally supplied barrier fluid at a pressure higher than the seal chamber pressure.

Face-to-back configuration – These seal are Arrangement 2 or 3 seals.  In which one stationary face is mounted between two flexible rotary unit or one flexible rotary unit between two stationary face. The inner seal is OD pressurized by process fluid and barrier or buffer fluid is on the ID of the inner seal.  The outer seal OD pressurized by barrier or buffer fluid.

Back-to-back configuration – These seal are Arrangement 2 or 3 seals.  In which both the rotary faces are mounted between two stationary flexible units. The pumping fluid is on the ID of the inner seal, and the barrier (pressurized) or buffer (un pressurized) fluid is on the OD of the inner and outer seal.

Face-to-face configuration – These seal are Arrangement 2 or 3 seals.  In which both the rotary faces are mounted between two flexible stationary units. The pumping fluid is on the ID of the inner seal, and the barrier (pressurized) or buffer (un pressurized) fluid is on the OD of the inner and outer seal.

A seal piping plan is designed, manufactured and supplied to improve the environment around the mechanical seal and therefore increase the performance and reliability of the seal. Piping plans range from very simple systems such as fluid recirculation into the seal chamber to complex systems which provide pressurization, cooling and circulation for support fluids and gases. The basic operation of the piping plan and also the requirements for instrumentation are followed as per API Standard 682 guidelines. Major piping plans supplied by Stein Seal® are Plan-21, Plan-23, Plan-32, Plan-52, Plan-53A, Plan-53B & Plan-53C.

Our API 682 seal design features, manufacturing capabilities and test facilities are witnessed and certified by a third party international certification organization. API 682 product offerings and capabilities can be found on our website www.steinseal.in

To keep mechanical seal systems functioning as long as possible, we recommend using standardized seal piping plans. Detailed API seal piping plans ensure minimal seal face wear by maintaining the optimal seal chamber environment.

Since they were first formulated, seal piping plans have been maintained and remodeled by the American Petroleum Institute (API). Current plans are based on API 682 and are sorted numerically. In some cases, designated letters are also used to differentiate between plans.

Fleaxaseal is the leading manufacturer of heavy-duty, high-pressure, high-temperature seals for the oil, gas & petroleum industry. Flexaseal supplies mechanical seals and seal support systems in the API market worldwide. We specialize in the specific challenges of emission controls, high pressures, speeds, and temperatures as well as sealing toxic, corrosive, and flammable products.

Our series of API Mechanical Seals are designed to fully comply with API seal plans’ design and qualification requirements. Our seal applications support a range of industries throughout refineries, petrochemical plants, and other industries.

Please contact AESSEAL Systems Division for further details. Tel: +44 (0)28 9266 9966 Email: systems@aesseal.com For more information, and a video demonstrating the piping plan in operation, select a plan below

Thomas Böhm, Head of Standardization – Division Mechanical Seals & API Task Force member and Markus Fries, Product Manager, EagleBurgmann GmbH & Co. KG, Wolfratshausen/Germany

The American Petroleum Institute (API) founded in 1919 has been occupying itself with technical standards since 1924. To this day, API has adopted roughly 500 standards that address the most diverse processes and components and which ensure a maximum of operating and process reliability. Individual standards - including the API 682 regulations for mechanical seals and seal supply systems - have become so popular in the meantime that they have been referenced in outside industry applications. The authors of the new edition point out that this had never been intended and clarify what API 682 is actually about: it concerns the seal systems in pumps of the oil & gas and (petro)chemical industries.

Initial information about mechanical seals was originally provided in the API 610 pump standard. During the 90s, API 682 then developed into a separate, more comprehensive standard for mechanical seals and supply systems. A typical quality of the API 682 standard is that is permanently updated by practical people. A further quality of the API 682 is that it does not normatively permit only a single technical solution. In addition to proven and tested standard solutions (defaults), the regulations also deliberately list alternatives (options) - and even allow customized solutions (engineered solutions).

The objective of API 682 is a continuous operation of the seal system for at least three years (25,000 operating hours subject to the legally stipulated emission values, or for max. "Screening Value" of 1000 ppm vol, EPA method 21), increased operational reliability, and simplified maintenance.

The 4th Edition includes the revised product coding system. The proven classification parameters "Category," "Arrangement," and "Type" will be continued. These are now listed first. Details regarding the supply system - specified as "Plan" - are also in the old and in the new code. The addition of precise information to material selection and shaft diameter is new. This gives more meaning to the Code and guarantees a clear specification of the mechanical seal and its operation.

The selection process of an API seal system is a complicated affair. Several flow charts and tables on more than 10 pages are dedicated to this topic in the new edition. In order to determine the seal arrangement more precisely, a scheme pursuant to the "Risk & Hazard Code" has been introduced in the 4th Edition for the first time. The starting point here is the pumped medium whose real hazard potential is accurately recorded and described by "Risk & Hazard Codes" in the "Material Safety Data Sheets." The selection scheme enables the quick and secure recognition of whether a single seal (Arrangement 1) is sufficient or if a double seal with barrier pressure system is required.

The "lived" standard of API 682 is also demonstrated in the new edition in that the two silicon carbide (SiC) variants "Reaction Bonded Silicon Carbide" and "Self-Sintered Silicon Carbide" can be used equally as "default" materials for sliding surfaces. Until now, sintered SiC was set for chemical applications due to its superior chemical stability, whereas the reaction bonded variant established itself in the refinery sector. This allocation was canceled due to practical application examples that were brought to the attention of the Task Force - and which called for a course correction.

Plan 53 with a pressurized barrier fluid belongs to the more complicated supply systems. In detail, three types are possible: Plan 53A is the solution with the constructively least amount of effort. The pressure on the barrier medium here is generated directly by the gas pressurization - normally with nitrogen - in the tank. However, the application has limits because higher barrier pressures could cause a dissolution of the nitrogen in the barrier medium. The consequence would be the risk of inadequate lubrication in the sealing gap of the mechanical seal. Higher barrier pressures are therefore the pursuit of Plans 53B and 53C.

Whereas Plan 53C works with a piston accumulator, putting it among the more sophisticated seal supply systems, Plan 53B uses an especially clever solution: Pressurization occurs via an elastomer bladder in the reservoir that separates the nitrogen from the barrier fluid. Pressure monitoring with consideration of the temperature in the bladder accumulator records the values and transfers them to the control room. The fill level with consideration of any temperature impacts is calculated there and the correct time for refilling the barrier fluid is determined.

A new prescribed refilling interval of at least 28 days has also been included in the 4th Edition. Consequently, the fluid reservoir must be large enough to reliably supply the seal with barrier fluid during this entire period. To obtain as compact reservoirs as possible, the seal manufacturers are required to find optimized system solutions with minimal leakage values.

The Task Force also addressed the topic of heat resistance of fittings for supply systems in an extremely pragmatic and practically oriented manner. In the past there were frequent debates about whether supply systems for high temperature applications – e.g. a 400°C-approved pump – has to be equipped with special instrumentation for the high temperature. Now the temperature specification for the instrumentation has been limited to a commonsensical 100°C. If instruments with higher temperature limits are required in the future the customer has to inform the seal vendor accordingly.

The essential improvements - in addition to all the technical supplements and updates - are the clear structures of the latest API regulation. The body of text was tightened and restructured, while technical details and background information were placed in the Annexes.

A special detail of the 4th Edition is the new red plugs that are inserted into the supply connections of the seal gland when the unit is delivered. These plastic closures prevent the ingress of dirt in the seal. During operation, the connections are either assigned to pipelines, or the plastic plugs are replaced with enclosed metal plugs. A nice side effect: 4th Edition API seals are quickly identified by the red plugs.

The EagleBurgmann API specialists Markus Fries and Thomas Böhm (from left to right) with a new developed API mechanical seal and the corresponding seal supply system according to API Plan 53B.

EagleBurgmann is one of the leading international providers of industrial seal technology that is used in diverse industries (oil & gas, power, refinery, chemical, energy, food, paper, water, and mining, among others). The company employs roughly 6,000 employees worldwide. 60 subsidiaries and 250 locations stand for global presence - and the associated proximity to the customer. The comprehensive product portfolio includes everything from well-engineered serial seals to application-related individual constructions.

API conform mechanical seals and supply systems take an important place in the EagleBurgmann range. For more than 20 years, the company has been consequently providing its know-how in further developing API specifications for the design of seal systems for the oil & gas and (petro) chemistry sectors - and is active in the API 682 Task Force. Worldwide there are more than 21,000 EagleBurgmann API seal systems in use.

Mechanical seals became the dominant sealing technology in refineries and chemical plants in the 1980s, causing the American Petroleum Institute (API) to establish a committee whose sole focus was to write standards for these components. The first edition, API 682 Shaft Sealing Systems for Centrifugal and Rotary Pumps was published in 1994 with this mission statement, “This standard is designed to default to the equipment types most commonly supplied that have a high probability of meeting the objective of at least three years of uninterrupted service while complying with emissions regulations."Currently in its fourth edition, API 682 continues to offer guidance based on process service for both mechanical seals and their support systems.

While much of the standard is focused on mechanical seals, a significant portion is devoted to seal support systems, as they are a critical component to the proper functioning of the seal and pump system. As a manufacturer of seal support systems, Swagelok Company and our sales and service centers have implemented the best practices of API 682 4th Edition. In this blog post, we will explain what some of those best practices are, and how implementing recommendations from the standard in the construction and design of your seal support systems can help you meet your goals of increasing reliability and safety while reducing costs.

Before we discuss best practices, let’s look at the functions of seal support systems. These systems are designed for a specific mechanical seal and set of process conditions. Typically, they supply either a gas or a liquid to the mechanical seal to regulate the environment in which the seal operates, protecting rotating equipment from damage.

Throughout API 682 4th Edition, there are references to reducing the number of connections in seal support systems. Whether welded pipe or tubing is selected for the system, threaded systems are discouraged. Every connection can be viewed as a potential leak point and possible reliability risk in hydrocarbon pumping applications. Leaks on seal support systems near pumps can cause asset damage, increased downtime, environmental issues, and safety risks.

In the past, many seal support systems were constructed out of pipe due to piping being historically preferred. More recently, seal manufacturers, end users, and pump OEMS have implemented tubing as a connection solution in seal support systems due to its long history of successful use in critical applications throughout the industrial world. As rotating equipment expert Heinz Bloch noted in a recent Hydrocarbon Processing article, “[the] American Petroleum Institute Standard 682 (API 682) began to endorse the use of tubing for some seal piping plans. Regrettably, tradition-bound purchasers still opt for hard pipe; we are asking them to reconsider. API 682 (4th Edition) now specifies seal support system connections almost interchangeably.”

Tubing can be utilized to reduce the number of connections by bending lines and appropriately using adapter fittings. Often, the only needed connections are those at the seal and the sealing system. Since tubing is annealed, bending the tubing work hardens the metal, increasing the strength of the tube at the bend. Innovative connection technologies such as flange adapters and extended male connectors further reduce the number of connections from threaded ports on the seal and seal pots by eliminating the need for multiple fittings. The use of tubing provides further financial benefit when we examine the MRO costs of the pump, seal, and support system. During maintenance operations where “piping” around pumps is reworked, the use of tubing eliminates the need for costly on-site welding and can be installed quickly to reduce downtime.

Seal support systems are critical to the proper operation of the seal and pump, and as such, require regular visual inspection. Making the job of visual inspection simple promotes system reliability and safety. When designing seal support systems, there are several best practice design principles to consider once the piping plan and general arrangement have been selected.

Mechanical seals are often damaged when pumps are started and stopped, sometimes as the result of improper seal support system operation. If the design of the seal support system facilitates proper operation, common mistakes when commissioning pumps can be avoided.

Additionally, API 682 supports these design considerations. It states: “All controls and instruments shall be located and arranged to permit easy visibility by the operators, as well as accessibility for tests, adjustments, and maintenance” (9.1.5)

Lastly, panels can include part numbering information, flow path indication, and operator instructions. These improvements help ensure safe and reliable startup and shutdown of pumps and seal support systems.

API 682 4th Edition also recommends block-bleed configurations for all gauges. If systems are not designed with this feature, it is likely that as gauges fail, operators will be left without critical information until the next turnaround or project when the pump and support system can be decommissioned and the gauge replaced.

Lastly, there are a wide variety of tubing connections and design options that allow for every serviceable component on a seal support system to be easily removed and replaced while continuing to operate the system. For seal pots, the 4thEdition stipulates “Local operation, venting, filling, and draining shall be accomplished from grade. Unless otherwise specified, systems that require the use of a ladder or step or that require climbing on the baseplate or piping are not acceptable” (8.1.8) .

Implementing these basic best practice design principles for mechanical seal support system increases reliability and reduces costs. To recap how you can realize better results with your systems:

Bringing pumps offline to fix minor instrumentation issues or fill seal pots should not be acceptable. Locating these systems on panels, with proper labeling and designing for easy maintenance reduces the chance for operator error which can damage seals.

Seal failures and the associated costs of seal replacement should be of great concern to rotating equipment groups at all plants. Ensuring that the best practices and design principals of API 682 4th Edition are followed helps prevent these costs and creates a safer and more reliable operation.

Swagelok provides design and assembly of seal support systems through our network of more than 200 authorized sales and service centers. We offer configurable, local, and reliable systems that are better by design to help you reduce costs, save time, and improve safety of your rotating equipment.

For additional advice on designing and installing your mechanical seal support systems, or to find the right API seal plan kits or assemblies for your applications, reach out to your local Swagelok team.

Many users do not like the strong handed approach used by API 682. However, with a little study of API 682, the user can easily learn to specify his preferences in detail using the seal data sheet.

Some statements within API 682 are normative, that is, required, whereas others are informative, that is, descriptive but not required.  In particular, many of the illustrations are informative.  This distinction has not always been apparent to the reader.

In spite of its strong handed approach, API 682 encourages innovative or developing technology. However, non-standard alternatives should be carefully discussed between the purchaser and seal company.

It is important to realize that API 682 is a users’ standard; it was written by and for the end users of mechanical seals and these users wanted to force changes.  The result was an entirely new standard written around a limited set of seal types, arrangements and materials that were favored by the end users in refineries.  These new seals were also required to be proven through a series of rigidly prescribed tests.  Although everyone agreed that API 682 seals were robust and well suited to the best practices of the refining industry, cost quickly became a limiting factor to the specification.  Consequently, API 682 1stEdition was not applied as extensively as had been anticipated. Subsequent editions have had an increase in the scope and also are more flexible with respect to defaults and options.

It is important to know the background and development of API 682 in order to fully understand and apply the standard. The story of API 682 begins in the late 1980’s.

By the late 1980’s, mechanical seals had been accepted as the preferred method for sealing rotating pumps for many years. However, prior to API 682, mechanical seal standards were generally buried in other standards such as DIN 24960, ANSI B73 and API 610. All of these standards were primarily pump standards and any references to seals were directed at how mechanical seals would interact with pumps.

In the late 1980’s a group of refinery equipment engineers and managers began to compare sealing solutions in refinery applications. This group, led by V. R. Dodd of Chevron, came up with a general plan and the American Petroleum Institute (API) agreed to establish a standard for mechanical seals: API 682.   A Task Force was formed in 1990 and the first meeting was held in January 1991.  This Task Force was comprised of fourteen members from various refineries, seal and pump manufacturers.   API 682, First Edition, was published in October 1994.

After nearly six years of intensive work, the American Petroleum Institute (API) 682 mechanical seal standard is soon to be adopted. Since its introduction in 1994, API 682 has become “the” standard that sets the global tone for the procurement and operation of seal and supply systems for centrifugal pumps in the oil and gas sector as well as in the petrochemical industry. API 682 is a “living” standard that directly incorporates diverse practical experience in its regular updates.

Founded in 1919 and located in Washington, D.C., the API includes close to 500 companies from the oil and gas sector and the petrochemical industry. Since 1924, it has focused on technical standards. To this day, API has adopted roughly 500 standards that address diverse processes and components in detail—which ultimately ensure a maximum of operating and process reliability. API standards, which are clearly defined and in part attached to approval tests, do not take effect only in the U.S. In many cases, they have developed into worldwide industrial standards. API is often considered a synonym for safety and reliability.

Individual standards—including API 682 regulations for mechanical seals and seal supply systems—have become so popular that they have even been referenced in outside industry applications. The authors of the new edition point out that this was never the intention and clarify the actual purpose of the API 682 standards. The standards are for seal systems in pumps—not in agitators or compressors—and for oil and gas and petro chemistry—not for water supply or the food sector.

Initial information about mechanical seals was originally provided in the API 610 pump standard. During the 1990s, API 682 developed into a separate, more comprehensive standard for mechanical seals and supply systems. The API 682 standard is continually maintained and updated by end users and manufacturers. Another quality of API 682 is that it does not typically permit only a single technical solution. In addition to proven and tested standard solutions (defaults), the regulations also deliberately list alternatives (options) and even allow customized solutions (engineered solutions). This diversity is demonstrated more clearly in this edition than in previous ones.

The composition of the 25-member task force is representative of the practical way in which API approaches the topic of seals. Since 2006, the task force has been updating the 3rd Edition of API 682 that took effect in 2004 and is still valid. In addition to leading seal system manufacturers, the American-European expert panel—which intentionally counted on non-API member collaboration—also included renowned planning companies and representatives from some of the largest mineral oil groups, who are users of seal solutions.

While the currently valid API 682 edition included approximately 200 pages, the 4th Edition is 260 pages. The revised edition is organized into a body of text with 11 chapters and detailed annexes with a significantly expanded scope. For example, Annex I provides detailed information on more than 20 pages for API-conform seal qualification tests.

Default seals and options must be tested using five different media and clearly defined operating conditions representative of typical API applications. Together with the described seal designs, this yields a high number of possible test variations. In the process, the expended time per test and seal type can take up to 200 hours. The result for typical industry seal designs is documented in a test certificate and a detailed report. Customer-specific qualification tests can be agreed upon for engineered seals.

Essentially, checked and tested product safety is the core of the standard. The objective of API 682 is continuous operation of at least three years (25,000 operating hours subject to the legally stipulated emission values, or for maximum “screening value” of 1,000 parts per million by volume, EPA Method 21), increased operational reliability and simplified maintenance. The standards defined by API apply exclusively to cartridge systems with a shaft diameter of 20 to 110 millimeters and a defined range of operating conditions.

The 4th Edition also includes the revised product coding system (Annex D). The proven classification parameters “Category,” “Arrangement” and “Type” will be continued. They are listed first in the revised code and provide information about the setup and field of use of the respective API seal. The seal arrangement includes:Arrangement 1—single seals are differentiated

Details regarding the supply system—specified as “Plan”—are in the old and new code. The addition of precise information regarding material selection and shaft diameter is new. This gives more meaning to the code and guarantees a clear specification of the mechanical seal and its operation—from selection to documentation. Industry experts agreed that the expanded coding system will prove itself in practice and endure permanently.

The selection process of an API seal system is complicated. Several flow charts and tables on more than 10 pages are dedicated to this topic in the new edition. To provide more precision in the technical selection process when determining the arrangement, an alternative selection tool (Annex A.4) has been included in the 4th Edition for the first time. This method is based on the established “Risk & Hazard Code” and has been tested in practice.

The starting point is the pumped medium. Its real hazard potential is accurately recorded and described by the “Hazard & Risk Code” in the “Material Safety Data Sheets.” Decisions can be made quickly and securely, for example, about whether a single seal (Arrangement 1) will suffice, or if a double seal with barrier pressure system is required.

The experience-based, “lived” standard of the API 682 edition is demonstrated by the two silicon carbide (SiC) variants, reaction-bonded silicon carbide and self-sintered silicon carbide, which are treated equally as default materials for sliding surfaces in chemical (Category 1) as well as in refinery/oil and gas applications (Category 2 or 3). Until now, sintered SiC was set for chemical applications because of its superior chemical stability, whereas the reaction-bonded variant established itself in the refinery sector. This restrictive allocation was canceled because of practical application examples (best practices) that were brought to the attention of the task force, which called for a course correction.

Plan 53 with a pressurized barrier fluid belongs to the more complicated supply systems. In detail, three types are possible:Plan 53A is the solution with the constructively least amount of effort. The pressure on the barrier medium is generated directly via gas pressurization—normally with nitrogen—in the tank. However, the application has limits, since higher barrier pressures could cause a dissolution of the nitrogen in the barrier medium. The consequence would be the risk of inadequate lubrication in the sealing gap of the mechanical seal. That is why Plans 53B and 53C are used for higher barrier pressure.

A new prescribed refilling interval of at least 28 days has also been included in the 4th Edition of API 682. The fluid reservoir must be large enough to supply the seal with barrier fluid for this entire period—without refilling. To obtain the most compact reservoirs, the seal manufacturers are required to find optimized system solutions with minimal leakage values for the barrier medium.

The transition to transmitters as default is illustrative: the API specifications primarily concern operating and process reliability and only then consider economic viability. This universal application is also verified by the decision of the task force to permit only seamless pipes in the future for “Piping” for the supply systems. The use of welded pipes, which would be less expensive, was considered unacceptable.

The task force also addressed the topic of heat resistance of the instrumentation used in supply systems pragmatically. In the past, frequent debates occurred regarding whether supply systems for high-temperature applications—for example, a 400 C approved pump—have to be equipped with special instrumentation for high temperatures. Now the temperature specification for the instrumentation has been limited to 100 C. If instruments with higher temperature limits are required in the future, the customer has to inform the seal vendor accordingly.

The essential improvements, in addition to the technical supplements and updates, are the clear structures of the latest API regulation. The body of the text was tightened and structured appropriately, whereas technical details and background information were placed in the annexes. Some of the wording in individual chapters was revised to improve understanding.

The improved user friendliness is shown in Annex E, which addresses structured communication and data exchange between suppliers and customers. Descriptions that previously encompassed many pages in API 682 are now bundled into two compact checklists in the 4th Edition. The first list systematically describes what must be considered for inquiries and quotations. It specifies the data that needs to be provided and the additional information and documents with which it must be combined. For example, seal systems that deviate from standardized API solutions must be shown separately. Annex E is completed by a second checklist that shows in which order the documentation is necessary.

Apart from the numerous technical updates and improved user friendliness, one detail is visually the most striking innovation of this edition: all mechanical seals are equipped with red plugs in the supply connections of the seal gland upon delivery. Until the unit is installed, these plastic closures prevent the ingress of dirt in the seal. During operation, the connections are either assigned to pipelines, or the plastic plugs are replaced with enclosed metal plugs. An additional benefit is that the 4th Edition API seals are quickly identified by the red plugs. Editor’s Note: This article was previously published in Upstream Pumping Solutions, July/August 2013.

After more than five years of planning, the American Petroleum Institute (API) is preparing to release the 4th edition of API Standard 682 (ISO 21049:2011). The API 682 standard, which dates back to 1994 and is formally known as Shaft Sealing Systems for Centrifugal and Rotary Pumps, offers specifications and best practices for mechanical seals and systems to pump end users.

The standard’s latest edition began to take shape in 2006, when API formed a 4th edition task force to respond to end users’ questions and comments about previous editions. The task force soon realized that major changes, including reorganization and editing, would be necessary. While addressing every aspect of the resulting 4th edition (which is more than 250 pages long) would be impossible, this article summarizes the standard’s main points.

Those who use API 682 should understand the standard’s scope and remember that the standard does not include specifications for equipment outside that scope, such as engineered seals or mixers. Another important but often misunderstood point is that API 682’s figures are illustrative and not normative in their entirety.

For example, one of API 682’s figures shows a fixed throttle bushing combined with a rotating Type A seal, but seal manufacturers do not always have to combine these two components. The standard provides normative details in clauses and tables to help purchasers distinguish between requirements and suggestions.

The 4th edition continues to divide seals into three categories, three types and three arrangements. For all practical purposes, seal manufacturers can combine a seal’s component parts into nearly any orientation or configuration. Each orientation and configuration has advantages and disadvantages with respect to certain applications, performance and system disturbances.

Before the 4th edition, API 682 did not specify a minimum clearance between the inside diameter of a stationary seal part and the outside diameter of a rotating seal part. The 4th edition specifies this minimum clearance—typically the clearance between the sleeve and the mating ring. The specified clearances are representative of standard clearances that end users have used for decades. End users should not consider seal components to be “shaft catchers” to restrict shaft movement. The minimum clearance specified in API 682 also applies only to equipment within the standard’s scope. Equipment outside that scope, such as non-cartridge seals, older pumps, non-API 610 pumps and certain severe services, might benefit from larger clearances.

The new standard also updates the default bushings for the gland plate for the three seal categories. Fixed throttle bushings are now the default for Category 1 only, while floating bushings are the default for Categories 2 and 3.

While the 4th edition features the recommended seal selection procedure from the standard’s first three editions, it adds an alternative selection method in Annex A. Proposed by task force member Michael Goodrich, this alternative method recommends using material data sheet information to select a sealing arrangement.

Plans 66A and 66B are new to the standard, although end users have used them previously in pipeline applications. These plans detect and restrict excessive leakage rates in case of an Arrangement 1 seal failure.

The 4th edition has revised the data sheets in Annex C extensively to make them the same for all seal categories. Only two data sheets are included in the 4th edition—one in metric units and one in U.S. customary units. The new edition also folds Annex J into Annex E.

Previous editions of API 682 required metal plugs and anaerobic sealants when shipping new or repaired cartridges. After much debate, the task force decided that threaded connection points should be protected with plastic plugs for shipment. These plastic plugs should be red and have center tabs that operators can pull easily to distinguish the plugs from metal plugs. Shippers should also attach yellow warning tags to the plugs to indicate that end users need to remove the plugs before operation.

Although tutorial notes are scattered throughout API 682, this edition expands the tutorial section, Annex F, from seven pages to 42 pages. The expanded annex includes illustrative calculations. In particular, users interested in systems such as Plan 53B will find Annex F to be useful.

The 4th edition of API 682 is the product of more than 20 years of discussion, debate, usage and peer review. It includes a strong set of defaults and is by far the best and most logical starting point for mechanical seal and systems use. Equipment operators should take the time to familiarize themselves with API 682 to get the most out of this comprehensive standard.

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A range of seals for mission-critical applications, designed to solve the application-specific challenges of each industry. From API 682 compliance for the oil and gas industries, using gas seal technology on our innovative pump gas seals to eliminate fugitive emissions, dealing with slurry in the mining and minerals processing industries, to the difficulties associated with maintenance on large pumps and rotating equipment — we have a solution.

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