All posts by Gallagher Fluid Seals

Gaskets for High-Density Polyethylene Flanges

Recent gasket failures in flanged joints of High Density Polyethylene (HDPE) piping.

Problem

HDPE piping joints are typically thermal fusion welded joints, but flanges may also be used. When flanges are used, an HDPE flange adapter with a metal backing ring is fused to HDPE piping, as shown in Figure 1. The HDPE flange adapters are used to connect to other flanged fittings, such as valves, elbows, tees, etc., with gaskets inserted between the flanged fittings.

Incident Description

Picture of Eroded GasketIn 2018, two HDPE flange adapter gaskets on two different valves that were part of an underground fire suppression system at a Department of Energy (DOE) nuclear facility in Amarillo, TX failed, causing several weeks of unplanned interruptions to nuclear facility operations. Fire suppression water was isolated to two nuclear facilities, requiring nuclear operations to be paused and fire watches to be established. Both couplings were installed by the same contractor and had been in service for approximately eight years. Both flanges were correctly torqued to 160 foot-pounds with no indication of the necessary re-torque. The initial failure of the gasket caused a low flow, high-pressure leak that was not detected for some time. Picture of Flange Face ErosionWith the system pressure operating at approximately 150 pounds per square inch (psi), the orifice created by the failure of the gasket(s) between the two flanged faces created a water jet, which eroded the metal valve flange and bolts.

Because HDPE will relax after the flange bolts are torqued, a re-torque after 24 hours is required. Even after the bolts are re-torqued, the face stresses drop to 400–600 psi. The lower face stress reduces the friction for maintaining the gasket in between the flange faces. The challenge is finding a gasket that can handle pressures that may exceed 200 psi, gauge (psig), but also seal well at relatively low stresses.

Due to the many inquiries from customers and engineering firms for gasket applications involving HDPE piping, Garlock, a gasket manufacturer, published a memo in January 2017 recommending using either GYLON® Style 3545 or MULTI-SWELL™ Styles 3760/3760U as the best options for HDPE flanges, even though the available compressive loads are lower than recommended. The reinforced gasket material of the GYLON and MULTI-SWELL has proven to prevent the internal water pressure from damaging the gasket under low-compression loads.

Other gasket manufacturers may have similar gaskets that will work for this application. It is important for the Design Engineer to work with the gasket manufacturer to properly specify the correct gasket.

Recommendations to HPDE Piping and Flanged Joints

When using HPDE piping with flanged joints, ensure that the flange bolts are re-torqued at least 24 hours after gasket installation.

When evaluating gasket material, be sure to include any surge pressure that could be caused by opening valve and starting pumps. Also, include any additional design/safety factors in your gasket calculation. And, directly work with the gasket manufacturer in making a selection.


If you have questions about HPDE piping and flanged joints or any other engineering applications, contact Gallagher Fluid Seals.

Original article written by Brian Rhodes, Department of Energy.

Six Reasons Bearing Isolators Leak Lubricant

A Lubrication Leak Doesn’t Always Mean a Seal Failure

picture of orion bearing protection device
Orion Bearing Protection Device

A well-known technique for increasing pump reliability is sealing the bearing housing with non-contacting bearing isolators rather than contact seals. Because contact seals use contact as their sealing method, they have a more limited life expectancy, since they can wear at the point of contact or groove the shaft. When this occurs, lubricant will escape to atmosphere and contaminants will enter the bearing housing, leading to bearing failure. Though more expensive, bearing isolators effectively retain lubricants and exclude contaminants while providing a virtually infinite life expectancy. This increases mean time between repair (MTBR).

The most common perception of bearing housing seal failure on process pumps is lubricating oil leaking from the bearing housing. For most operators, the analysis is simple: no leaking oil means the seal is fine while leaking oil equates to failure. Though true for contact seals, the presence of leaking oil from a bearing isolator is most likely due to factors other than seal failure.

Following are some of the more common causes of bearing isolator lubricant leakage in process pumps.

Common Causes of Bearing Isolator Lubricant Leakage

1. Too Much Oil

It seems simple, but the greatest cause of bearing isolator leakage on process pumps is an over-filled bearing housing. It has become common practice for maintenance professionals to fill up to, if not a bit over, the maximum fill line. The thinking is that if leakage occurs, there will be extra lubricant available. This practice can inadvertently contribute to leakage. Fortunately, once returned to the proper level, bearing isolators will generally stop leaking and return to normal function. There may be some oil leakage as the seal clears itself of excess lubricant, but that should diminish over time.

2. Orientation

Most bearing isolators have a lubricant return designed into their respective labyrinth patterns. This return needs to be installed at the bottom dead-center or six o’clock position of the bearing isolator for proper function. This allows oil to easily return to the sump. One of the most common causes of improper seal orientation is a lack of training or unclear installation instructions.

3. Obstructed Lubricant Return Path

Picture of Klozure ISO-GARD_BLUE
Garlock’s Klozure ISO-GARD Bearing Isolator

Most modern bearing isolators are effective at collecting splash lubricant in their respective labyrinth patterns. Once they have collected the lubricant, they need a clear, unobstructed path to return collected lubricant back to sump. But the return path to the sump may be blocked by counter-bores in the housing, which were originally designed to provide a positive stop for pressed-in lip seals. The area between the bearing and the bearing housing seal may lack a drain channel. When this occurs, lubricant will accumulate in this area until the space becomes completely flooded and the seal leaks. To solve this, the area between the bearing and the bearing isolator must include an unobstructed return pathway to the sump. Relying on the lubricant to drain to sump only through the bearing will likely result in lubricant leakage.

4. Improperly Applied External Oilers

External oilers are extremely sensitive to position and must be installed on the proper side of the housing relative to the direction of shaft rotation following the manufacturer’s guidelines. Oilers must also be installed square and straight. The pipe connecting the external oiler to the bearing housing must also be sufficiently ridged to prevent vibration or shaking the oiler. Questionable installations of may result in over-filling of the bearing housing and subsequent lubricant leakage.

5. Wind

The forceful flow of air over a bearing housing can cause lubricant leakage by creating a pressure differential between the inside and outside of the bearing housing. Couplings and external cooling fans attached to pump bearing housings are a potential source of harmful air flow. Gapless, solid coupling guards that enclose the bearing housing seals with little or no gap around the bearing housing may induce leakage. While taking all required safety precautions, having some of the coupling and fan guarding accomplished by tight grating, rather than solid surfaces, allows for better air flow and helps prevent pressure from building.

6. Improper Non-Contact Seal Selection

Some bearing isolators are designed specifically for grease lubrication, others for oil or oil mist. There are some designs that can handle all lubrication types in a single design. In some instances, benefits can be achieved by designing bearing isolators for specific applications rather than relying on standard catalog items. For example, in pump bearing housings with a high degree of lubricant splash, designing the labyrinth pattern to communicate directly with the lubricant return path can greatly increase effectiveness. Experienced bearing isolator providers can design engineered-to-order seals quickly and economically, and ensure the seal design addresses any concerns and is applied to provide the best reliability possible. Time spent on up-front engineering tasks is well worth the effort, and assures the bearing isolators will perform as intended.

The advantage of non-wearing bearing isolators is that once properly applied, they perform essentially trouble-free for years with no degradation in performance. The challenge is that they require a bit more attention to application details. Taking the time to check a few simple parameters will go a long way towards ensuring trouble-free operation.


For more information about bearing isolators and how Gallagher can help engineer a custom solution for your, contact Gallagher Seals engineering department.

The original article can be found on Pumps & Systems website here.

Low Temp Gaskets – How Low Can You Go?

Rare and Ultra-Pure Resources Present Unique Challenge to Finding Appropriate Low Temp Gasket

Modern technology often requires rare or ultra-pure materials that can only be handled or obtained within extreme environmental conditions. These same conditions present unique and hazardous difficulties when transporting or utilizing these resources. Resources such as liquid oxygen, nitrogen, or argon; all of which are classified as “industrial gases” are handled well below the normal temperature ranges that every-day liquids exist; ranging as low as -195.8°C (-320.4°F). This often makes it a challenging task to find a low temp gasket to fit the specifications for the application.

As an example, let’s look at argon; an important gas used in Welding, Neon Lights, 3D Printing, and Metal Production, just to name a few. It is far more economical to house and transport argon in its liquid state. However, it must be held at an astonishingly low -185.9°C. Fitting the pipes together and maintaining a seal in a cryogenically engineered system that the liquid argon is housed presents unique difficulties. Argon gas is colorless, odorless, tasteless, and can irritate the skin and the eyes on contact. In its liquid form it can cause frostbite.

There are important considerations that should be taken into account when installing gaskets for dangerous extreme low temp materials.

Proper Gasket Installation

Many gasket materials can become brittle, crack, shrink, and blow out when exposed to extreme cold – not something you want to happen at any time, let alone with a liquid that can freeze you into a meatsickle. So, proper installation is also key. During installation, it is important that all parts are dry, the installation is done at ambient temperature, and then re-adjusted with changes in temperature.

Cryogenics

Any mechanical seal that is sealing a product with a temperature below 0 degrees Celsius is given the name “Cryogenic”. Liquefied gases (LNG), such as liquid nitrogen and liquid helium, are used in many cryogenic applications, as well as hydrocarbons with low freezing points, refrigerants and coolants.

When selecting a low temp gasket or sealing material to be used in cryogenic service, it is important that the material can withstand cryogenic temperatures.

Low temperature applications are found across many industries, these include:

  • Chemical
  • Food
  • Pharmaceutical
  • Refrigeration
  • Petroleum
  • Automotive

Garlock GYLON® and KLINGER SLS/HL

3500 and klinger flexible graphite

Good gasketing materials that can withstand the frigid cold and are pliable in the requirement to maintain the seal would be the Garlock GYLON family of gaskets (PTFE, capable of -450°F (-268°C)) or the Klinger SLS/HL, which is made of flexible graphite and can withstand -400°F (-240°C)

Conclusion

As with all gasket applications, environmental conditions should be considered in conjunction with the functional requirements of the device. Though there are limited options to solve extreme low temp gasketing challenges, Gylon and Klinger can be a good fit for your application.


Portions of the original article were written by Michael Pawlowski and Sylvia Flegg of Triangle Fluid Controls Ltd. The article can be found on Empowering Pumps website here.

For more information about low temperature gaskets and which might be a fit for your application, contact Gallagher Seals engineering department.

Theme Park Thrills Owe Much to Hydraulics and Accumulators

Article re-posted with permission from Parker Hannifin Hydraulics Team.
Original content can be found on Parker’s Blog.


AccumulatorsMost people enjoy theme parks as a place to get away from work, but for those in the hydraulics industry, they are a place to demonstrate their expertise. Behind many of the rides that make your stomach drop or your eyes blink in amazement, Parker’s accumulators are picking up the stresses and enhancing the performances of hydraulic technology.

Behind the scenes, there is complex machinery that must run precisely and smoothly to ensure safe and reliable operation. Whether you are splashing through water, sailing above the tree lines, or being wowed by animations and simulations, powerful equipment that depends on the science and engineering of hydraulics is enriching your activities.  And, many of these large, powerful hydraulic systems rely on accumulators; hidden from the public view, but critical in their roles.

The Role of Accumulators

Typically, accumulators installed in hydraulic systems store energy to either provide an extra boost of power or absorb energy to smooth out pulsations. One of the world’s largest manufacturer of accumulators is Parker’s Accumulator and Cooler Division. According to Jeff Sage, product sales manager, the Parker accumulators used in theme parks are gas-charged and are either bladder accumulators or piston accumulators. Parker manufactures both types and has the engineering expertise to recommend which kind best fits the requirements of a particular ride.

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Contamination Control for Power Generation

Power Generation - Air Sentry® Desiccant BreathersCoal fired power generation plants produce electricity making conveniences of modern life possible. The process and environment from which power flows is challenging for equipment. Water and coal dust are ever present. This combination of moisture and dust are the two most common avoidable contaminates found in lubricants.

For this environment, the Air Sentry® X Series or XR Series is the best choice for performance, serviceability and value. For stationary applications, Air Sentry® X Series, with double check valve design, delivers maximum life for the silica gel desiccant and the cost savings of a replaceable cartridge. The double check value design allows air exchange as needed, while maximizing desiccant life in a wet, humid environment. For mobile or high vibration applications, such as conveyor lines, the XR Series with metal reinforced base is the best choice.

Pump manufacturers report a 50% increase in service life if pump lubricants are protected from airborne contaminates. Bearing manufactures report a 3 fold increase in bearing life when lubricants maintain ISO cleanliness standards. With Air Sentry® on duty, equipment is more reliable, downtime is reduced and return on investment increases.

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Style 404 Expansion Joint for Abrasive Applications

Abra-Line Style 404The ABRA-LINE™ family of products was developed for highly abrasive applications typically found in the power generation, fertilizer, mining and chemical industries. These may include flue gas desulphurization systems, phosphate mining, dry bulk power transfer systems, tailings and slurry applications. Our proprietary urethane formula was designed to reduce wear and extend
service life.

Style 404 Expansion Joints are specially designed for full vacuum abrasive service applications. The tube material is a proprietary urethane formulation. Style 404 can be constructed as a single or multiple arch design. It can also connect pipe flanges in concentric or eccentric tapers, to join piping of unequal diameters.

Case Study: Chemical Processing

Industry
Chemical Processing

Observation
A stainless hosing was used and would continuously fail due to abrasion on the leading edge of the hose. The hosing would last for 3 to 6 months before replacement.

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Resolving Food and Beverage Challenges

When it comes to sealing food and beverage systems against leaks, contamination and malfunctions, meeting a product specification does not guarantee that seals will function as needed, two Freudenberg-NOK Sealing Technologies experts told a webinar audience in September. Freudenberg-NOK runs the business operations for Freudenberg Sealing Technologies in the Americas.

Food and BeverageFreudenberg’s David Clark, Operations Manager, Central Laboratory and with Ryan Fleming, Analytical Laboratory Manager, provided insight about the nature of elastomers, market trends like custom flavor combinations, regulatory requirements and the importance of material compatibility and advanced analytical testing. All of these factors must come into play when choosing the right material to produce effective elastomer components for food and beverage machinery, they emphasized during their Beyond a Spec: Choosing the Right Sealing Materials for Food and Beverage Applications webinar.

“Today’s global industry means engineering for multiple markets and diverse regulatory compliance standards, which can be challenging and expensive, so it must be considered early,” said Clark. “Simply meeting a product specification does not ensure a seal will function.”

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Self-lubricating Composite Wear Rings

Composite Wear RingsCIP Composites are laminated polymer materials made by impregnating textiles with thermoset resins. Solid lubricants are added to the resin to provide evenly dispersed lubrication throughout the material, providing smooth operation.

CIP custom composite wear rings are a superior alternative to commonly used cotton phenolic and glass filled nylon materials. They allow smooth operation and high side loads while protecting the sealing elements and preventing metal to metal contact in hydraulic cylinders. CIP wear rings are preferred where high performance, large diameters and/or high temperatures are required.

CIP Composite wear rings provide manufacturers and servicers alike with solutions to reduce overall maintenance and increase wear life. CIP offers short lead times, reducing the costs associated with equipment downtime and repairs. CIP Composites are manufactured in the United States using only the highest quality materials.

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VA179: Industry Leading High Temperature FKM

High Temperature FKM - VA179The O-Ring & Engineered Seals Division of Parker Hannifin Corporation, the global leader in motion and control technologies, recently announced the launch of VA179, a new extreme high temperature fluorocarbon (FKM) compound. VA179 is an innovative, 70 durometer rubber seal material providing increased high temperature limits while maintaining chemical resistance and low temperature sealing consistent with standard FKMs.

VA179 consists of a breakthrough rubber technology increasing the FKM continuous high temperature limit an additional 20°C (68ºF) over standard FKM materials on the market today. This provides a new industry sealing solution to long-term compression set issues for customers using traditional fluorocarbons and silicones.

“In markets such as aerospace, automotive, and heavy-duty, we are frequently challenged to expand the temperature capabilities of our rubber compounds,” says Nathaniel Sowder, aerospace, military and chemical processing business development engineer, O-Ring & Engineered Seals Division, “With the launch of VA179, we now have a solution that will reach higher temperatures without sacrificing the low temperature and chemical resistance attributes that make standard FKM such a popular choice.”

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BLUE-GARD 3300 for Refrigeration

In the late nineteenth century, Olin J. Garlock devised a better way to seal piston rods in steam engines. Since then sealing materials have been developed for various industrial applications. Over the years, different manufacturing processes such as calendering and beater addition have improved the performance of fiber sheet gaskets for these applications; however, design concepts for their formulation remain similar regardless of manufacturing method.

Figure 1: Microstructure of a compressed fiber sheet material ingredients: silicates [gray]—laminated structure; mineral [blue and aqua]—irregular/spherical shape; fiber [orange]—fibrillated, cylindrical or curly; silica, carbon black, or fine filler [red]—spherical shape; elastomer binder [yellow].

OVERVIEW OF MATERIALS

Many of the applications for compressed fiber sheet gaskets involve elevated temperatures and/or high pressure, which require high bolt loading in flanged joint assemblies. Various materials are added to the fiber-binder matrix to sustain this high compressive loading. To provide strength, different types of fibers such as p-aramid (Kevlar™), cellulose, polyester, glass fiber, carbon fiber, and others are added. Some of these fibers are organic materials, which limits their use at elevated temperatures. Minerals in cylindrical form provide balance in the formulation due to their high-temperature stability and strength. To form a compact structure, materials of different sizes are used, including silica, carbon black, and other micro-sized fillers. Figure 1 illustrates the ingredients and microstructure of a compressed fiber sheet material.

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