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.

The Complete Guide for Mechanical Seals & API 682 4th Edition Piping Plans

Mechanical Seals & API 682 4th Edition

A sealing system, consisting of a mechanical seal and an associated supply system that is balanced by individual applications, is the utmost guarantee for a reliable sealing point and uninterrupted pump service. The performance of the seal is greatly influenced by the environment around the seal faces, making the provision of suitable, clean fluids as well as a moderate temperature an essential topic.

This guiding booklet provides a condensed overview of all piping plans established by the API 682 4th edition guidelines. Each illustrated piping plan is briefly described, and a recommendation that considers the media characteristics in terms of the relevant application and corresponding configurations is given to help you reliably select your sealing system. Furthermore, the content of this booklet has been enriched by providing clues – so-called ‘remarks and checkpoints’ – where EagleBurgmann shares the experiences gained from multiple equipped plants.

Sealing solutions to meet any requirement

Several factors play a major role when choosing the product, the product type, the materials used and how it is operated: process conditions at the sealing location, operating conditions and the medium to be sealed.

No matter what requirements our customers have, EagleBurgmann understands how these factors affect functionality and economic viability, and they translate this expertise into outstanding long-term, reliable sealing solutions. EagleBurgmann has all the expertise needed to manage and support the entire development, life and service cycle of its sealing solutions.

Plan 75 Piping Plan Example

EagleBurgmann and API 682

EagleBurgmann offers customers the widest product portfolio of seals and seal supply systems according to API 682 4th edition. The configurations listed for each individual piping plan are to be understood as recommendations including possible utilizations which may also be applied.

EagleBurgmann Profile

EagleBurgmann is one of the internationally leading companies for industrial sealing technology. Their products are used wherever safety and reliability are important: in the oil and gas industry, refining technology, the petrochemical, chemical and pharmaceutical industries, food processing, power, water, mining, pulp & paper and many others. More than 6,000 employees contribute their ideas, solutions and commitment towards ensuring that customers all over the world can rely on their seals and services. More than 21,000 EagleBurgmann API-seals and systems are installed world-wide.

How AMS3678 Ensures Consistency in Sealing Materials

When it comes to designing and developing seals, the aerospace and industrial industries need a basis to allow production anywhere in the world.

One of the first PTFE (Teflon) standards, AMS3678, describes Teflon and the addition of fillers. This was used in conjunction with Mil-R-8791, which is one of the Mil specs describing a backup ring device.

The origin of all these specs dates back to the creation of the O-ring.

AMS3678The Origin of the O-Ring Patent

In 1939, Niels A. Christensen was granted a U.S. Patent for “new and useful improvements in packings and the like for power cylinders.” These referred to improved packing rings made of “solid rubber or rubber composition very dense and yet possessive of great liveliness and compressibility.” These products were suitable for use as packings for fluid medium pistons (liquid or air). The improved packing ring is the modern O-ring.

There was a progression of standards for the O-rings created by individual countries, such as AS568, BS 1806, DIN 3771, JIS B2401, NF T47-501, and SMS 1586. Eventually, AS568 became more accepted in the industry.

The backup ring was originally created to help improve the O-ring’s ability to resist extrusion. Teflon was widely used as one of the materials for backup ring devices. Standards were created to unify the production of this Teflon device.

The Progression of Mil Specs

The progression of standard changes has led to AMS3678/1 for Virgin PTFE through AMS3678/16. These standards describe a group of Virgin- and filled-PTFE materials accepted by the industry for manufacturing seals and back-up ring devices.

Mil-R-8791 was canceled in February 1982. This spec was superseded with AS8791, which eventually evolved into AMS3678.

AMS3678 is a tool used by customers and Teflon suppliers to create uniformity in the manufacturing and processing of seal and bearing materials. The standard is inclusive of most of the compounds upon which the industry was built.

When customers approach with an old “mil spec”, they are pushed to the new AMS spec which is currently active. Eclipse manufactures to the spec so their customers will have the confidence that they manufacture to a known standard.

When crossing custom materials from well-known sources, customers are driven to an accepted spec that is equivalent to the original source of the material. This helps customers sell their products with internationally-known materials rather than custom, home-grown compounds that are often intended to single source those materials.

There are several qualifications of the spec that suppliers must observe. This includes dimensional stability tests. This test ensures the material has been properly annealed, and that the seal or backup ring will fit and function as it was originally intended.

Eclipse is uniquely qualified to supply parts to the latest AMS3678 specification. They understand the scope of the specification which allows us to ship parts with fully traceable certification.

AMS3678 helps validate a material to a customer to ensure they get the same material processed the same way with each order. Beyond this, there are other ways to determine what makes a part process-capable.

Continue reading How AMS3678 Ensures Consistency in Sealing Materials

A Case Study: GYLON® 3504 and 3545 Gaskets

Wine Manufacturing with GYLON®

Gylon 3504

Picture of Garlock 3545The GYLON® Style 3504 gasket is made of PTFE with aluminosilicate microspheres. It is designed for use in many acids, some caustics, hydrocarbons, refrigerants, and more.

Gylon 3545

The Garlock 3545 style is a highly compressible microcellular PTFE with a rigid PTFE core for improved handlability. Garlock 3545, made with Gylon material, is designed to compress and conform to irregular or damaged surfaces, making it suitable for flanges that generate lower compressive stresses, such and glass-lined flanges and equipment.

INDUSTRY

Food & Beverage – Wine Production

CUSTOMER

An award-winning, family owned & operated winery in the heart of a major US wine-growing region.

BACKGROUND

The customer crushes, presses, ferments, bottles, and labels all of their wines at their winery, but having traditionally utilized EPDM gaskets, they faced ongoing issues with seal reliability. This was occurring during various stages of the winemaking process, but especially so during the sterilization procedures between each batch, with subsequent leaks creating issues in production reliability, housekeeping, and potential contamination.

CHALLENGES FACED

Business was growing rapidly so new equipment had been installed, but at the same time the number of maintenance windows was reducing. Therefore the customer was looking for a more reliable and sanitary product to improve efficiency and help to protect the sensitive product. As well as the need to remain absolutely compliant with industry standards, the customer also placed utmost importance on prevention of any adulteration of their award-winning wine. As well as working around limited windows of opportunity for production trials the critical and expert opinion of wine tasters was therefore essential to ensure full approval of any component change in the process.

Continue reading A Case Study: GYLON® 3504 and 3545 Gaskets

Freudenberg Announces New Seals and Materials for the Aerospace Industry

Freudenberg Sealing Technologies introduced several new material and sealing innovations at the 2019 International Paris Air Show.

These new products are designed to help aerospace customers address ever increasing safety and performance requirements in the industry.

During the June 17-23 event in Paris, Freudenberg showcased a new high temperature, fireproof material; an Omegat OMS-CS cap seal; and new ethylene propylene diene monomer (EPDM) and a fluoroelastomer (FKM) developmental material.

“Our aerospace customers strive continuously to be faster, safer and more efficient, which in turn requires us to innovate to help them reach those goals – a challenge we enthusiastically embrace,” said Vinay Nilkanth, vice president, Global Mobility Sector, Freudenberg Sealing Technologies. “The launch of several new products aimed at improved performance underscores Freudenberg’s commitment to being a global leader and development partner to the industry.”

Freudenberg’s new proprietary fireproof sealing fabric is made to withstand the extremes. Tested on standard aerospace bulb seals and passing AC20-135 fireproof requirements, the fabric acts as a barrier, providing up to 15 minutes for necessary corrective action. The fabric performs as well as other industry standard solutions but is much more cost effective.

Omegat Cap Seal

For use in dynamic, reciprocating applications where low friction is required, the new Omegat OMS-CS cap seal is a two-piece rod seal set consisting of an engineered polytetrafluoroethylene (PTFE) ring and an O-ring energizer. The seal offers low breakaway and running friction, and is chemically compatible with aerospace fluids and greases. It also provides excellent wear and extrusion characteristics, and has angled blow-by notches and lubrication grooves.

Freudenberg’s new EPDM LM426288 material is for use in low pressure static sealing to -77°C (-106°F) and has excellent resistance to, and swell behavior in, AS1241 phosphate ester hydraulic fluids. The material offers high temperature compression set resistance and short term resistance to 150 °C (302°F) for high temperature hydraulic systems such as hydraulic braking.

The FKM LM426776 material for use in low pressure static sealing to -67°C (-88°F) shows excellent resistance to several aerospace media, including jet turbine and gearbox lubricants, high and low aromatic content jet fuels, and fire resistant hydrocarbon hydraulic fluids. The material offers short-term high temperature resistance to 270°C (518°F) and long-term compression set resistance at 200°C (392°F).


The original article can be found on Freudenberg’s website.

Gallagher Fluid Seals is a preferred distributor of Freudenberg Sealing Technologies. To learn more about Freudenberg products, speak to a Gallagher representative today by calling 1-800-822-4063

Vesconite Bearings – Three Dakar Rallies With No Grease

The Dakar Rally – What is it?

The Dakar Rally (or simply “The Dakar”) is an annual rally raid organized by the Amaury Sport Organisation. Since its inception in 1977, most races took place from Paris, France, to Dakar, Senegal. But due to security threats in Mauritania, which led to the cancellation of the 2008 rally, races since 2009 have been held in South America. The race is open to both amateur and professional entries, of which amateurs typically comprise of eighty percent of all participants.

The race is an off-road endurance event. The terrain that the competitors traverse is much tougher than that used in conventional rallying, and the vehicles used are true off-road vehicles rather than modified on-road vehicles. Most of the competitive special sections are off-road, crossing dunes, mud, camel grass, rocks, and erg among others. The distances of each stage covered vary from short distances up to 800–900 kilometres (500–560 mi) per day.

Vesconite Hilube Bushings in Suspensions of Colcar’s Racing Team Vehicles

Colcar Racing Team is a partner of Vesconite, and used the no-grease Hilube busings in the suspensions of their racing vehicles during the 2019 Dakar Rally.

The use of Vesconite Hilube in the Argentinian team’s vehicles builds on a growing record of Vesconite Hilube use in their yearly Dakar entries.

In 2018, Vesconite Hilube bushings were fitted to two trucks, one of which finished in position 23. In 2017, meanwhile, the Argentinian team finished in 33rd position, and continued to use their Vesconite Hilube bushings for two other local competitions that covered a total distance equivalent to three Dakar Rallies.

For the 2019 Dakar Rally, Colcar Racing Team participated in the truck category (vehicles weighing more than 3,500 kg – or 7,700 lbs), as well as the utility vehicle (UTV) category, also known as four-wheel side-by-side vehicle or recreational off-highway vehicle category.

The Colcar UTV won its category and finished 18 overall.

Colcar Racing Team's VehicleVesconite’s polymer bushings put to the test in the 9,000 km race

“The polymer bushings have proven themselves over the grueling annual 9,000 km multi-country South American Dakar endurance race that covers various terrains, including sand dunes, mountains and salt flats,” comments Leandro Panzini of VesArg, the Argentinian distributor of the Vesconite Hilube.

“Suspension bushings are important in vehicle safety, ride comfort and handling and also align suspension and steering components … and they are paramount in the Dakar, in which vehicles travel at between 100 and 200 kilometers per hour (62-124mph) in all kinds of terrain over 15 days,” he says.

In the Dakar vehicles, the bushings were exposed to an oscillating movement with many cycles per minute taking place, and performed much better than the nylon-molybdenum bushings that they replaced, reports Panzini, who is proud to have Vesconite Hilube associated with this historic race and performing so well each year in race vehicles.

Watch the video below about the Colcar team during this year’s Dakar Rally:


Gallagher is a distributor of Vesconite products for all industries.  If you have questions about using Vesconite in any application, contact our engineering department.

EagleBurgmann Shaft Seals in Waste Paper Treatment

Waste paper treatment is of great significance in the paper industry. The collected and sorted waste paper is fiberized in pulpers using large amounts of water with the addition of chemicals and is sorted into slightly and heavily contaminated fractions.

In the de-inking process, the printing ink is removed by means of chemicals and mechanical forces and is skimmed as foam from the surface in the subsequent flotation.

The risk of dry running for the mechanical seal is especially great for the machines used in the flotation process. The seals in the coarse screening are subjected to intense stress due to the contaminations inclined to plaiting. Know-how and experience in the selection of seals and materials are requirements in order to ensure optimal and trouble-free operation.

The shafts of bleaching agent pumps, MC pumps, dispersers, slurry pumps, sorters, pulpers and fiberizers are successfully equipped with EagleBurgmann single and double seals of the LP, M7N, M74, HR and Cartex-DN series. Thermoflon and Buramex type compression packings reliably seal bleaching agent pumps and separators in the waste paper treatment process.

Waste Paper Treatment Process

Waste Paper Treatment Process


Successful Mechanical Seals for Waste Paper Treatment Facilities

Kartonsan Turkey PumpsIn Kartonsan Turkey, numerous pumps for pulp treatment and in the de-inking system have been successfully equipped with EagleBurgmann Burasoft 6225-L type compression packings.


UPM Kymmene ShottonAt UPM Kymmene Shotton in England, nine Voith pressure screens in waste paper treatment are being used successfully with EagleBurgmann HR-D type double cartridge seals. Medium to be sealed: Pulp fibers 1.5 … 4 % abs. dry and water, p = 8 bar (116 PSI), t = max. 40 °C (104 °F).


Palm Worth GermanyIn the waste paper treatment at Palm in Wörth, Germany, four TL200/TL300 type Metso Screens with LP-D-ST-D15/130-DE were retrofitted to non-flow operation and have been running in continuous operation (24 hrs./day) since 2004. Medium: Pulp 3 % abs. dry and water, t = 50 °C (122 °F), p3 = 4 bar (58 PSI), n = 800 min-1.


Stora Enso Maxau GermanyAt Stora Enso Maxau, Germany, Voith slot sorters in a waste paper treatment plant for the production of standard and upgraded newsprint paper are sealed with EagleBurgmann HR10 type seals (“dead-end”). Flushing with circuit water (return water) is used only when the medium has a too high solids content. Face material combination SiC/SiC, shaft diameter d1 = 46 … 130 mm (1.81” … 5.12”), p1 = 1 bar (15 PSI), t = 60 °C (140 °F), n = 980 min-1, medium: Paper pulp (0.2 … 5 % abs. dry). The Palm Paper Ltd. paper mill produces newsprint for national and international newspapers. Production is based solely on waste paper pulp.


Palm Papter Ltd. TotalSealCare Service AgreementA TotalSealCare service agreement having a duration of several years includes servicing of all installed mechanical seals for pulp pumps, mixers and various pressure screens. Additional contractually agreed services are on-site presence during start-ups, troubleshooting and providing seal-related schooling and training courses for plant personnel.


To Learn more about which seal might be right for your application, contact us today at 1-800-822-4063 or click the button below.

Contact Gallagher

A Closer Look at Parco’s 4200 Nitrile Seals

Nitrile (NBR) is a copolymer of butadiene and acrylonitrile. Due to its excellent resistance to petroleum products and its ability to be compounded for service over a temperature range of -30°F to +250°F, Nitrile /NBR is the most widely used elastomer in the seal industry today. NBR o-rings are very versatile, inexpensive material which contributes to its wide array of applications.

Let’s start with the 4200-70 General-Purpose Nitrile Seal. What differentiates this material?

1. Excellent Physical Properties

Parco’s 4200-70 70-durometer nitrile O-rings have excellent physical properties. For nearly 40 years, 4200-70 O-rings have been used in a wide variety of  applications with great results. So when you specify 4200-70, rest assured that you’ve made the right choice.

2. Excellent Resistance to Compression Set

To perform properly, seals must resist taking a set from compression after being installed. When a seal takes a set, it no longer exerts force on the mating surfaces, resulting in leakage. A compound with low compression set, like 4200-70, better maintains its elastomeric properties and original thickness, preserving seal integrity. Seals made from Parco’s 4200-70 compound provide excellent resistance to compression set. After testing 4200-70 for 22 hours at 212°F, it had a compression set of only 6 percent.

Compression Set of a Typical Parker 70-Duro Compound

3. Very Good Resistance to a Variety of Fluids

NBR O-ring compounds, like 4200-70, provide very good service in gasoline, crude oil, power steering fluid, hexane, toluene, water, water-based hydraulic fluids, and dilute bases such as sodium hydroxide.

So, what’s the chemical resistance of 4200-70?

  • Automatic Transmission Fluid
  • Crude Oil
  • Gasoline
  • Propane
  • Water

More than 50 percent of sealing needs can be met using nitrile. Its versatile nature might be right for your application and you don’t even know it. Consider NBR before opting for something more complex!


About Parco

Founded in 1941, Parco was the first manufacturer to specialize in O-rings, still one of its primary products. Today, Parco has four modern facilities manufacturing O-rings, custom-molded elastomeric seals, rubber-to-metal bonded parts, and machined metal parts. Their 154,000 square-foot facility in Ontario, California is one of the largest plants in the world making molded rubber seals. The three other facilities in Texas and Louisiana specialize in complex custom-molded elastomeric products, machined metal parts, and machined plastics.


The datasheet for Parco’s 4200-70 can be found by clicking here.

Gallagher Fluid Seals is an authorized distributor for Parco. For more information, contact our engineering department.