epix

How the raised surface profile of PTFE sheet gasket helped a midstream oil and gas processor address leaky pipes

Bolted flange-gasket connections in process piping systems are common and given little thought – unless they start to leak.

Chronic leakage proved to be an issue for one of Garlock's clients, a midstream oil and gas processor and services provider. The site processes, stores, and transports natural gas, liquefied natural gas and petroleum products. Garlock was brought in to provide a solution to the problem.

Successful connections are dependent on a variety of things, including the state of the flange surfaces, alignment, bolt and nut grade and strength, bolt and nut thread condition, lubrication, bolt tightening process, service conditions, and choice of gasket.

When a flange-gasket joint is assembled, the gasket must first be compressed to fill the gaps between the flange surfaces, creating a seal when system pressure is applied. Secondly, it must maintain that seal as the system is brought on-line and temperature and pressure escalate.

As the temperature increases, a gasket made of non-metallic materials such as rubber, fibre, PTFE and inorganic fillers is prone to lose thickness, that is, creep. And the thicker the gasket is, the
more it is prone to creep (1/8-inch thick gaskets creep more than 1/16-inch).

The two most important performance qualities of a gasket are its ability to seal and its ability maintain that seal. These can be indicated by industry standard tests for sealability and creep.

On the surface, this particular case study would seem to be an application of little complexity. However, the details of the joint gave rise to several issues that caused the user chronic leakage problems. Here are the service conditions and background of this particular case:

• Temperature: 100°F to 120°F (38°C to 49°C)
• Flanges and use: 18-inch Class 150 raised face flanges used in the pipe systems of cooling tower water pumps. Multiple gaskets are on either side of spool piece
• Media: Water
• Pressure: 100 psig to 150 psig (7 bar-g to 10.3 bar-g)

GYLON EPIX® is a family of gaskets that effectively seals a broader range of applications and is more forgiving during the installation process.  It allows the end user to save valuable turn-around time, reduce re-work, and lower costs, helping them to finish ahead of schedule and under budget.

GYLON EPIX® features a hexagonal surface profile that provides the torque retention and blowout resistance of a thin gasket and the conformability of a thicker gasket.  GYLON EPIX Style 3504 is a high performance, aluminosilicate microsphere filled PTFE sheet material designed for use in moderate concentrations of acids, and caustics, as well as hydrocarbons, refrigerants, and more.

INDUSTRY

Chemical

CUSTOMER

Chemical Manufacturer and Distributor

BACKGROUND

Loading stations are very critical in the chemical industry as flanges are disassembled and reassembled everyday.

CHALLENGES

Gylon Epix's patterned material provides enhanced compressibility for better sealing

Gaskets are ubiquitous components in a processing plant. Every flange, equipment joint and connection point will have some form of gasket to prevent fluids from compromising (i.e., leaking from) a process system. However, effective sealing can pose challenges. A new form of polytetrafluoroethylene (PTFE) gasket, Gylon Epix, already has successfully addressed a number of persistent problems at plants.

The gasket, which is available in 3⁄32-in.-thick, 60-in. × 60-in. sheets, features a raised hexagonal pattern (Figure 1). It exhibits enhanced

Enhancing the surface profile can improve sealing capabilities, extending the functionality of aging piping systems in chemical plants.

There are many aged and aging process plants in operation today. In fact, many of the processing plants for power, chemicals, oil, etc., have been in service for more than 50 years. And while the piping itself may remain intact, their bolted flange gasket joints and connections are becoming misaligned, corroded and damaged due to repeated handling, chemical exposure and thermal cycling. This can lead to costly ruptures that may result in millions of dollars in damages, downtime, noncompliance penalties, irreparable environmental impact and litigation.

There is a solution that can extend the life of aging piping systems, preserving their functionality: raising the surface profile on polytetrafluoroethylene (PTFE) gaskets. This design modification can prevent leaks, spills and other releases in chemical processing plants by reducing and managing the contacted area of the gasket, thus achieving and maintaining a strong seal.

A Brief History of Gasket Technology

Traditionally, gasket thickness and sealability always involved a performance tradeoff. One could use 1/16-inch-thick (1.6 millimeter) gaskets when flanges were in good condition, achieving a tight seal with reduced creep.

However, when the flanges had bad or misaligned surfaces, the seal integrity was degraded.

In those instances when the flanges are in poor condition (or if the shape of the flange condition is unknown), one would choose a 1/8-inch-thick (3.2 mm) gasket. The reason? A user does not want to risk installing a thinner gasket and discover that it does not seal properly, which then requires a timely and costly uninstall and reinstall. However, the thicker gaskets do not seal as well as their 1/16-inch counterparts when placed under comparable load. Additionally, with the thicker gaskets, creep is higher, requiring re-torque.

To address the limitations of both gasket options, the ideal gasket should combine the creep resistance of a 1/16-inch gasket with the compressibility and conformability of a 1/8-inch gasket—easier said than done.

Historically, gaskets have not always been forgiving, easy to use or simple to remove. Yet technology has evolved, allowing sealing products to be engineered and designed to optimize the work that is put into them, delivering a tighter, more durable seal.

The approach is one that does not focus on the gasket thickness but rather its surface profile. The results produce gaskets that reduce leaks, spills and other releases from piping systems, including those of aging chemical plants.

Raising the Gasket Profile

The concept of using surface profiling to reduce area and increase stress is found in many products, such as running shoes and car tires. Reducing the contact area while maintaining a given amount of compressive force results in increased stress. In the case of shoes or tires, this stress provides traction. In the case of gaskets, traction or friction between a gasket and a flange face is critical to holding internal pressure. If the downward force created by the fasteners in a flange is evenly spread over a larger area, the created stress contributes to making a seal more effective. This approach enables the aging piping system to maximize its sealing potential.

Impact on Raising Gasket Profile

Surface profiling positively impacts gasket technology in five key areas: compressibility, pressure resistance, scalability, load retention and dimensional flexibility.

Compressibility

Compressibility is a critical functionality of gaskets, as it represents the ability of the gasket to conform to the surfaces that it seals. Adding raised features to the surface of a gasket directly impacts compressibility by reducing the contact area and increasing the resulting stress.

When flange surfaces are worn, pitted or scratched—such as those in aging piping systems in chemical plants—it can be cost prohibitive and nearly impossible to repair/replace the flange to a “good as new” condition. The more compressible the gasket, the better chance of producing an effective seal with the flanges.

We recently added the GYLON EPIX™ - The Next Generation in PTFE Gasketing webinar to our website.  The webinar discusses Garlock's revolutionary new gasketing material, with its patented hexagonal surface, which concentrates gasket stress, providing improved compressibility and bolt load retention, improving sealability and blowout resistance.

Below is the third and final section of the webinar, which provides application guidance for GYLON EPIX™, calling out where it makes most sense to utilize this revolutionary new material.

https://youtu.be/U-koqMPko0w

We recently added the GYLON EPIX™ - The Next Generation in PTFE Gasketing webinar to our website.  The webinar discusses Garlock's revolutionary new gasketing material, with its patented hexagonal surface, which concentrates gasket stress, providing improved compressibility and bolt load retention, improving sealability and blowout resistance.

Below is the second section of the webinar, which discusses the features and benefits of the GYLON EPIX™ material, and what differentiates it from any other gasketing material on the market today.

https://youtu.be/WzooJzGNa8w

We recently added the GYLON EPIX™ - The Next Generation in PTFE Gasketing webinar to our website.  The webinar discusses Garlock's revolutionary new gasketing material. With its patented hexagonal surface, GYLON EPIX™ concentrates gasket stress, providing improved compressibility and bolt load retention, improving sealability and blowout resistance.

Below is the first section of the webinar, diving into what drove Garlock to create this new material, and how GYLON EPIX™ provides the benefits of both a 1/16" and 1/18" thick gasket in one, universal, 3/32" thickness.

https://youtu.be/PS_uc5BUDwc

Gallagher recently added the GYLON EPIX™ Webinar to its website. This video is a recorded webinar discussing GYLON EPIX™ - The Next Generation in PTFE Gasketing.

This material is a newly developed family of PTFE gaskets. It is manufactured using a patented, profiled surface based on our proven Fawn  (Style 3500), Off-White (Style 3510), and Blue (Style 3504) GYLON^® to create highly conformable materials for optimum sealing performance.

GYLON EPIX™ will provide superior functional performance by combining the traditional attributes of GYLON^® with an innovative surface design. It offers a broader range of applications than traditional PTFE gaskets that are used in worn and pitted flanges. In addition, GYLON EPIX™ delivers the tight sealing and load retention properties of 1/16” (1.6mm) and the conformability of 1/8” (3.2mm).

GYLON EPIX™ is a family of gaskets that effectively seals a broader range of applications and is more forgiving during the installation process.  It allows the end user to save valuable turn-around time, reduce re-work, and lower costs, helping them to finish ahead of schedule and under budget.

GYLON EPIX™ features a hexagonal surface profile that provides the torque retention and blowout resistance of a thin gasket and the conformability of a thicker gasket.  GYLON EPIX™ Style 3504 EPX is a high performance, aluminosilicate microsphere filled PTFE sheet material designed for use in moderate concentrations of acids, and caustics, as well as hydrocarbons, refrigerants, and more.

INDUSTRY

Chemical

CUSTOMER

Phosphate Processor

GYLON EPIX™ is a newly developed family of PTFE gaskets. It is manufactured using a patented, profiled surface based on our proven Fawn, Off-White, and Blue GYLON® to create highly conformable materials for optimum sealing performance.

THE EPIX™ DIFFERENCE

GYLON EPIX™ and a traditional full face gasket were installed in a 3”-150# flat face flange at 120 ft.lbs. with pressure sensitive film.  The film revealed that the traditional material saw heavier loading-near and around the bolts, and lighter loading at the points furthest from the bolts. The GYLON EPIX™ was able to distribute the load more evenly and prevent the low loading phenomenon.

The pressure sensitive film was then analyzed with special software that translate the various shades of red into a full color spectrum that provides a better visualization of the stresses that were developed on each of the gaskets. Again, while the traditional gasket saw areas of lower stress (green and blue areas), the hexagonal pattern in the GYLON EPIX™ concentrated and distributed the stress more evenly across the entire gasket.