by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

The Basics of Ball Valve Seat Materials

Ball valves play a critical role in controlling the flow of fluid and pressure within a pipeline, but their effectiveness and safety is only as good as the seat material used. In this blog post, we are going to review the basics of five commonly used ball valve seat materials.

Ball Valves

Whether found in a petrochemical application where a leak could be environmentally devastating, or in a pharmaceutical laboratory where cleanliness and sanitation are critical, ball valve seats must be reliable and robust. A ball valve consists of the body of the valve, the body cap, the stem, the hollow ball, and the round ball valve seat. 

The ball valve seat is responsible for sealing the fluid inside and uniformly distributing the seating stress. In soft seat ball valve designs, either an elastomer or polymer is used as the seal and are inserted into a metallic seat ring. This approach, as opposed to hard seat ball valves, is popular because it provides good sealing action, is lighter weight, and more cost effective. 

Key Properties of Ball Valve Seat Materials

When choosing a polymer material for a ball valve seat, there are numerous factors that are involved. Key material properties include …

  • Sufficient ductility to provide a reliable seal
  • Dimensional stability to ensure the ball valve seat retains its shape for reliable sealing and performance
  • Very low friction to keep stem torque at a minimum
  • Low coefficient of thermal expansion so that the ball valve seat retains its shape when temperature changes occur
  • Excellent wear resistance for a long service life
  • Chemical compatibility with all media involved 

In some operating environments, it is also important that ball valve seat materials exhibit these properties:

  • Low moisture absorption to prevent dimensional changes in the presence of water or high humidity
  • Maintain performance with repeated sterilization that can include hot water, steam, and harsh cleaning chemicals
  • Good performance in the presence of sudden decompression (i.e., pressure drops over 650 psi)

Recommended Materials for Ball Valve Seats

There are several materials that work well as ball valve seats, including acetal, PEEK, PTFE, TFM, and UHMW-PE.

Acetal Ball Valve Seats

When aggressive environments are involved, Acetal (also known as Delrin) is often used. Acetal provides excellent wear resistance, is very rigid, has good toughness, and is resistant to cold flow. Although its operating temperature range is not very wide (-70°F to 180°F), it can handle pressures up to 5,000 psi. Acetal also works well in radioactive environments  but should not be used with oxygen flow.

PEEK Ball Valve Seats

PEEK offers excellent chemical resistance, very low friction, self-lubrication, and is flame retardant while also possessing a wide operating temperature range (from -70°F to 550°F). It can handle very aggressive applications and works well when there is a need for hot water and steam exposure–but does not do well in the presence of sulfuric acid.

In addition, PEEK is very well adapted to nuclear applications and is available in FDA-approved grades as well as filled grades with improved wear properties and better thermal conductivity. Note that PEEK is usually chosen for ball valve seats when the operating temperature range is outside that of PTFE.

PTFE Ball Valve Seats

PTFE (also known by its trade name, Teflon) has many of the same properties as PEEK, but involves even lower friction, dry running capabilities, and more extensive chemical compatibility. Like PEEK, it is available in FDA-approved grades and can handle cryogenic temperatures down to -50°F and high temperatures up to 550°F as well as pressures up to 5,000 psi.  \

Also like PEEK, PTFE can continue to perform even when repeatedly exposed to hot water and steam. Keep in mind, however, that PTFE does not perform well in the presence of fluorine or alkalies. PTFE is also very easy to clean and available in glass or carbon-reinforced grades that can provide improved wear characteristics, less propensity to cold creep, and lower thermal conductivity. 

TFM Ball Valve Seats

TFM (sometimes referred to by the brand name Dyneon) is a second-generation PTFE material that combines the best properties of PTFE (low friction, chemical resistance, high-temperature performance) with better stress recovery and the ability to handle higher pressures. It is also more elastic and resilient than PTFE. The operating temperature of TFM ranges from -100°F to 450°F and it is well adapted to applications involving steam and thermal fluids.

UHMW-PE Ball Valve Seals

UHMW-PE, which stands for Ultra-High Molecular Weight Polyethylene, has a low coefficient of friction, an operating temperature ranging from -70° F to 200°F, good chemical resistance, good dimensional stability, and good abrasion resistance. In general ball valve seats made from UHMW-PE can handle pressures up to 1,500 psi and can handle low to medium levels of radiation exposure.

Conclusion

Ball valve seals are used in many different industries, including chemical processing plants, oil and gas operations, manufacturing facilities, food preparation, and even residential use. As a leak-proof means of pressure and flow control, their smooth and reliable operation is critical–which is why polymer materials work extremely well for ball valve seats. If you are in the market for a ball valve seat material, contact the experts at Advanced EMC. We can put our years of experience to work for you, helping you select the right material for your project.

 

by Jackie Johnson Jackie Johnson No Comments

Benefits of PTFE For Sealing Applications

PTFE (Polytetrafluoroethylene), also known by its trade name Teflon, is a polymer material commonly used in sealing applications that offers unparalleled stability and sealing characteristics across an extremely wide range of temperatures, from the extreme heat of a space shuttle engine to the cryogenically cold temperatures used to preserve

In this article, we will discuss how and why PTFE is one of the best materials to use for seals in a wide variety of applications.

Low Friction

PTFE has the highest melting point and lowest friction, and is the most inert of all the fluoropolymers. It has a continuous service temperature rating of 500 degrees Fahrenheit. Molding powders are excellent, fine cut granular resins, well suited for a variety of demanding chemical, mechanical, electrical and non-stick surface applications.

Such applications include:

  • Cookware
  • Outdoor Rain Gear
  • Medical Devices
  • And more!

Cryogenic Applications

Cryogenic seals are used with super-cooled media, like liquid hydrogen or compressed natural gas, at temperatures below -238°F and down to -460°F (absolute zero). Cold temperatures like this are rough on a seal because at these temperatures most materials begin to exhibit highly brittle behavior and lubricants typically cannot be used because they will freeze. PTFE seals, however, can handle temperatures all the way down to -450°F and are capable of dry running because of their extremely low friction. PTFE cryogenic seals are used in industries like oil & gas, pharmaceuticals, and aerospace.

High Temperature Applications

PTFE seals work well at the other end of the spectrum, too. They can continue to function in extreme temperatures up to 600°F, and continuous operating temperatures up to 600°F. Note that a filler may be required to enable the PTFE to dissipate heat more quickly. It’s not uncommon to see PTFE seals in petroleum or steam applications where temperatures greatly exceed 200°F.

PTFE is also non-flammable, making it ideal for use in applications such as jet propulsion engines. Where other materials would simply melt under the pressure of constant exposure to high temperature flames, PTFE is built to withstand even the hottest of environments.

The use of seals for high temperature applications include oil and gas industry and aerospace, to name a few.

Chemical Applications

The chemical resistance of PTFE is some of the best on the market. It is stable in most aggressive and corrosive media, including:

  • Acetone
  • Chloroform
  • Citric Acid
  • Hydrochloric Acid
  • Sulfuric Acid
  • Tallow
  • Sodium Peroxide
  • And more!

However, it should be pointed that that PTFE is not chemically resistive to liquid or dissolved alkali metals, fluorines and other extremely potent oxidizers, as well as fluorine gas and similar compounds. Outside of those, PTFE is an excellent choice for applications involving chemicals.

Oil and Gas Industry

Seals are critical for the safe and reliable operation of oil rigs across the globe. Not only do seals need to be able to withstand a wide variety of extreme temperatures, but they need to be able to handle extreme pressures as well. For well drilling, for example, seals need to handle pressures from 345 to 2070 bar (5000 to 30000 psi).

For those reasons, PTFE is an incredibly popular material to make oil and gas seals out of. Because of it’s resistance to heat, cold and high pressure, PTFE can withstand the rigors of oil and gas unlike any other material.

Spring-energized Seals

In order to retain sealing power under extreme temperatures, many engineers and designers go with spring-energized PTFE seals. The spring provides optimal sealing by forcing the lip of the seal against the mating surface and helps to account for dimensional changes as a result of temperature fluctuations.

A highly efficient seal is created as the system pressure increases enough to take over from the spring and engage the shaft or bore. The spring or energized seal assembly provides permanent resilience to the seal jacket and compensates for jacket wear, hardware misalignment and eccentricity. The jacket material is critical in design to assure proper seal performance.

Rotary Shaft Seals

Using PTFE in rotary shaft seals allows them to be able to run at higher pressures and velocities when compared to other materials. They are also able to have tighter sealing, often exceeding 35 BAR and can run at far more extreme temperatures ranging from -64 degrees Fahrenheit (-53 degrees Celsius) to 450 degrees Fahrenheit (232 degrees Celsius).

On top of that, they are:

  • Inert to most chemicals
  • Can withstand speeds up to 35 m/s
  • Compatible with most lubricants
  • Come in a wide range of sizes
  • And more!

Conclusion

PTFE is an ideal sealing material for both extremely high temperature applications and demanding cryogenic applications. It retains its key sealing properties: stiffness, strength, dimensional stability (may require spring energizer), low friction, and chemical compatibility- even in the most aggressive operating conditions.

Need PTFE sealing solutions? Advanced EMC Technologies is the leading provider of PTFE spring energized and rotary shaft seals in the US. Contact us today!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

7 Things to Know About FlexForce Canted Coil Springs

FlexForce canted coil springs have special characteristics that make them useful in a variety of applications, ranging from locking components together in an orthopaedic implant to providing an energizer for mission critical aerospace applicants. In this blog post, we will introduce seven key facts about FlexForce canted coil springs that you need to know.

Are a Specific Design for Springs

Canted coil springs, also known as slant coil or cant coil springs, are springs that have the individual coils set at an angle to each other, rather than having them all parallel. This coil configuration significantly impacts the performance of these springs and makes them ideal for a wide range of uses.

What makes canted coil springs different from other types is the fact that they have a flat load curve when they are compressed. Because of this, canted coil springs generate predictable loads throughout their wide deflection range.

Can be Used as Mechanical Connectors

Canted coil springs are ideal for applications that involve latching, locking, or holding to connect two components (also known as detent mechanisms). Latching involves fastening two parts together so that they can still be disconnected when needed. Locking creates a permanent connection that can only be broken by damaging the sea. Holding, on the other hand, both retains and aligns parts and makes sliding possible via the controlled spring force. 

Canted coils are commonly used to connect two mating surfaces in a highly predictable, repeatable fashion thanks to the flat load curve. When canted coil springs are used, the insertion/removal force can be engineered to a high degree of accuracy.  And when used as a latching, locking, or holding connector, FlexForce canted coil springs provide a lightweight, high strength option that can be used for practically an infinite number of cycles.

Can Provide Exceptional EMI/RF Shielding

One of the common uses of canted coil springs is their ability to effectively provide EMI/RF shielding. Furthermore, the electrical properties of these springs can be customized to provide more optimal shielding against certain ranges of conductive and radiated interference.  

Add to this the fact that they can adapt to irregular and uneven shapes to provide consistent shielding, and it is easy to see why they are a common choice for applications that need to be protected from harmful electromagnetic and radio frequency crosstalk interference.

Can Act as a Multiple Point Electrical Conductor

Some designs depend on multiple electrical contact points, which a canted coil can provide. Using a canted coil spring for electrical connections results in a reliable connection that results in a cooler operation temperature. It allows engineers to manage more power in compact spaces and provides both conducting and grounding capabilities in both static and dynamic applications. In addition, canted coil springs as electrical conductors can perform in some of the harshest operating environments that may involve vibration and shock. It should come as no surprise that canted coil conductors are often used in medical applications inside the human body.

Can be Used with Spring Energized Seals

Canted coil springs work extremely well as the energizer in spring-energized seals. Because of the energizer, spring energized seals are able to maintain contact with the sealing surface, even if issues such as out of roundness, uneven mating surface, runout, hardware gaps, eccentricity, or seal lip wear are present. 

The flat load curve of these springs also means that friction stays fairly consistent in dynamic sealing applications. This makes them ideal for sealing situations that involve critical friction and torque specifications. In addition, canted coil springs are very unlikely to experience compression set. 

Available With a Range of Options

There are several options for canted coil springs. They are available in varying levels of spring force: light, medium, and heavy. And canted coil springs come in both standard and custom sizes. As to the spring wire itself, they are available in wire diameters between 0.25 mm (0.010 inches) and 1.50 mm (0.059 inches). As to the coil width, they come in sizes ranging from 1.5 mm (0.039 inches) and 15 mm (0.591 inches). However, designs can be highly customized if needed.

Finally, the three most common wire materials are Hastelloy, stainless steel (usually 300 series), and copper alloys. For use as a conductor or EMI/RF shielding, stainless steel is recommended. For applications that involve high heat and corrosive media, Hastelloy and Elgiloy may be recommended. Also keep in mind that these canted coil springs can be obtained with nickel, silver, or gold plating.

Used in a Wide Range of Industries and Applications

Canted coil springs are being used in a diverse group of industries and applications, including oil & gas, renewable energy, aerospace, defense, fluid power, transportation, semiconductor manufacturing, and medical devices

  • As a mechanical connector, canted coil springs are often used to lock together frame assembly of a ventilator cart or to hold components together in wind turbines.
  • As a multiple contact point conductor, canted coil spring assemblies are often used in active implantables such as pacemakers or neurotransmitters. 
  • As EMI/RF shielding, canted coil springs can be found in electrical enclosures or used with data transmission cables.
  • As a part of a spring energized seal, canted coil springs are used in critical aerospace applications and dangerous petrochemical environments involving extreme heat and corrosive materials.

Conclusion

FlexForce canted coil springs can be used as detent mechanisms, EMI/RF shields, multipoint electrical conductors, and energizing springs in seals. They are available in a number of options and can be fully customized to meet user needs. In addition, their reliable performance has already been proven in number industries and applications. If you are interested in FlexForce canted coil springs, contact us at Advanced EMC today.

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Benefits of Hytrel for Sealing Applications

Hytrel (property of the Dupont Company) is gaining in popularity as a material for seals, and there a number of reasons for this. In this blog post, we are going to talk about the general characteristics of Hytrel as well as the specific grades used for sealing applications.

What is Hytrel?

Hytrel is a TPC-ET thermoplastic polyester elastomer made by Dupont. Hytrel can be found in applications that seem to vary significantly in requirements and environmental challenges, such as off-road transportation equipment, oil and gas, hydraulic power, food handling, and medical devices. It is also used in electronics, automobiles, healthcare equipment, power tools, sporting goods, appliances, and cables.

Characteristics of Hytrel

Hytrel has a long list of excellent characteristics, including impact resistance, toughness, and resistance to chemical attack (including hydrocarbon solvents and fuels). In terms of sealing applicants, it offers:

  • Flex fatigue resistance
  • Spring-like properties
  • Creep resistance
  • Inherent flexibility
  • The ability to flex in multiple directions
  • Wide operating temperature range (cryogenic to +315°F)

In addition, Hytrel retains mechanical properties even at high temperatures and remains flexible at low temperatures. Hytrel also lends itself to a variety of manufacturing methods, including extrusion, blow molding, injection molding, and rotational molding. However, it is sensitive to water and phosphate fluids above 175°F.

Grades and Blends of Hytrel

Hytrel is available in various grades and blends, including seven specific grades that are well-adapted for seals. In addition to the grades discussed below, there are also renewable sourced options. Note that stabilizing additives can be combined with these grades to improve Hytrel’s resistance to heat aging and UV light.

Hytrel 4056

Hytrel 4056 is the most flexible grade, offering both toughness and strength over a considerably wide temperature range. It works extremely well for low-temperature applications because of its ability to retain flexibility. In addition, its low modulus allows it to be formed using extrusion and has a low melting point.

Hytrel 4068 and Hytrel 4069

Both Hytrel 4068 and 4069 provide flex-fatigue and creep resistance along with outstanding low-temperature properties. These grades can be formed using molding or extrusion and possess a higher melting point than Hytrel 4056 and a lower modulus. In addition, there is a food-grade available: Hytrel 4068FG.

Hytrel 4556

Hytrel 4556 is very similar to 4068 and 4069, with a low-to-medium modulus and can be manufactured using both extrusion and molding. This grade works extremely well for seals and gaskets.

Hytrel 5526 and Hytrel 5556

In terms of general properties, Hytrel 5526 provides a good balance. Its flow properties, however, primarily limit it to injection molding. Hytrel 5556 also offers a balance of properties with a medium modulus. It works well with extrusion but does not have the same high-flow properties available with Hytrel 5526. 

Hytrel 6356

Hytrel 6356 offers an excellent balance of properties such as toughness, flexibility strength, thermal resistance, and creep resistance. This high modulus grade is well adapted both to molding and extrusion processes.

Hytrel 4053FG NC010

When food contact grade seals are needed, Hytrel 4053FG NC010 may be an option. This is a low modulus extrusion grade whose properties include creep resistance, good low-temperature properties, and flex-fatigue resistance. 

Hytrel 5553FG NC010

This is a medium modulus molding and extrusion grade of Hytrel that provides a good balance of properties. It is intended for applications involving food contact.

Hytrel 6359FG NC010

Another good grade option of Hytrel, this material provides a good balance of properties including strength, toughness, flexibility, creep resistance, and thermal resistance. It is a medium to high modulus grade that works well with both molding and extrusion processes.

Benefits of Using Hytrel

When used in sealing applications, Hytrel offers a number of distinct benefits. For example, Hytrel can be used to replace multi-piece assemblies (including those composed of various materials) with a single component.

Because Hytrel has excellent creep and recovery properties, seals using Hytrel will be more resistant to dimensional changes and less likely to be permanently deformed. This is critical in many sealing applications, including those where there are extreme pressure and temperature changes. And because it can flex in multiple directions for far more cycles than a traditional elastomer such as rubber.

Unlike some seal materials, Hytrel grades vary according to modulus, which makes Hytrel a very versatile material choice. The differences in modulus are important: low modulus options can be used where little force should be needed to stretch the material, while high modulus grades work well for situations where significant force should be required to result in stretching. In addition, Hytrel is available in Shore D hardness ranging from 30 to 82.

As mentioned earlier, Hytrel has excellent properties when it comes to chemical compatibility and resistance to chemical attack. More specifically, it is resistant to mineral oils, greases, water-based hydraulic fluids, dilute acids, dilute bases, glycol, and hydrocarbon fuels. There are also grades of Hytrel that offer excellent resistance to the degrading effects of radiation. 

Hytrel is available in food grades that conform to both FDA and  European Food Contact regulations.  There are also grades in compliance with regulatory requirements that make them suitable for use in medical devices and other healthcare applications.

Conclusion

Hytrel combines the strength of engineering plastics with the flexibility of elastomers and the ease of processing provided by thermoplastics. Its combination of properties and flexibility in terms of manufacturing processes make it an excellent option for sealing applications

by Jackie Johnson Jackie Johnson No Comments

Polymer Seals and How They Are Used in Space

Today more and more countries are entering the space industry. According to the Space Foundation, the global market for space exploration was a whopping $383.5 billion worldwide in 2017, with a 100% increase in the total number of spacecrafts deployed. It is expected to grow to $1.1 trillion by 2040.

As the space market opens up, so does the need for technology that assists with cost, sustainability, efficiency and safety- such as seals.

In fact, polymer seals have been used in a variety of functions for spacecrafts such as:

  • Propulsion
  • Payload Systems
  • Ground Support Equipment
  • Regulators
  • Main Fuel and Oxygen Valves
  • Regulators
  • And more!

In today’s blog post, we will explore the use of polymer seals in the space industry.

A Changing Landscape

Since the first expedition into space in 1961 by Russian cosmonaut Yuri Gagarin, there has been a surge in emerging countries and private sectors entering the space race.

In 2002 Elon Musk founded SpaceX, a private company whose goal is to manufacture and launch advanced rockets and spacecrafts with the goal of enabling commercial trips into space. In 2010 it became the first private company to return a spacecraft from low Earth orbit in 2010 and the first commercial spacecraft to deliver cargo to and from the International Space Station in 2012.

In India, the Indian Space Research Organization (or ISRO) has developed a massive and ambitious space program. In 2014 they launched their Mars orbiter, becoming the fourth space agency and the first in Asia to reach the red planet. In 2017, it launched 104 satellites in a single rocket, tripling Russia’s record.

With so many new players entering the scene, the space industry has never looked more exciting. This also requires an increase in demand for high quality parts, such as polymer seals.

Space is Cold and Engines are Hot

Polymer spring energized seals are commonly used in a variety of space applications because of their durability and ability to withstand extreme temperatures.

With temperatures in space reaching cryogenic (-238*F or -150*C) it is important that the seals used can withstand the extreme temperatures. The outer polymer lip of a spring energized seal for example allows the seal to be used in temperatures of -423*F (-253*C) to 302*F (150*C).

On top of having seals that can be used in the cold, dark vacuum of space, seals are also used in conjunction with things like thrusters, combustion chambers, and other parts of the shuttle where temperatures can reach a whopping 6,000*F (3,315*C).

Aggressive Chemicals

Many seals face frequent exposure to liquid oxygen and liquid hydrogen, the latter of which must be below 20K (-423*F or -253*C) in order to reach a liquid state. This puts an incredible amount of strain on the seal. One way around this is to make seals out of high-quality polymers such as PTFE, Torlon and more.

Increase of Pressure

In outer space, the pressure is 1.322 x 10-11 Pa. For those keeping track at home, this is essentially zero. However, the act of leaving the Earth’s atmosphere causes such a huge fluctuation in pressure that there is a potential for metal and other hardware to open, which in tern could potentially impact the seal.

As such it is critical that seals used can hold up to the extreme fluctuation of pressure, and continue to run, to keep the shuttle and its crew safe.

Teflon, or PTFE, is a popular material used because of its ability to not only handle extreme temperatures, but extreme pressure fluctuations as well.

Cost Efficiency

As of 2012 it is estimated that the average launch cost of a NASA space shuttle is around $576 million. That cost does not factor in the price to build the craft, which values at a whopping $3.5 billion. As such, it behooves space programs to find ways to not only be cost efficient, but to be sustainable as well.

Luckily, with seals, making them out of polymer materials solves both problems!

Because of it’s ability to be produced at high volumes, making seals out of polymers can greatly reduce overhead cost. And because the plastic can be melted down and reused, they are highly sustainable as well!

In Conclusion

With more and more people interested in space exploration, it is becoming more and more critical to have high quality parts to perform critical functions.

Polymer seals are the best choice for companies looking to have a high quality, cost efficient, and sustainable part that will withstand the rigors of space travel.

For more information, or to learn how Advanced EMC Technologies can help your spaceship blast off, contact us today!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Spring-Energized Seals for Aerospace and Defense

In aerospace and defense applications, seals can be found in gearboxes, flap actuators, aircraft braking systems, actuators, turbopumps, cryogenic refueling systems, and hydraulic systems. They are necessary for land and ground defense systems, seaborne systems, ships, UAVs, airborne systems, and aircraft. But finding a sealing solution that provides the right mix of reliability and performance in the harsh environments associated with such applications can be challenging. However, there is a solution: spring-energized seals.

Spring-Energized Seals

Spring-energized seals are designed with a stainless steel spring designed to keep the seal lip in contact with the sealing surface despite wear, eccentricity, pressure changes, dimensional changes, and out-of-roundness. Spring-energized seals are often implemented when other sealing solutions have failed.

When the right jacket material is chosen, spring-energized seals can also handle some of the harshest operating conditions, including exposure to corrosive or reactive chemicals, extreme temperatures, wide temperature and pressure ranges, and environments where lubricants cannot be used.

The Challenges of Aerospace and Defense Sealing Solutions

Because both aerospace and defense applications are mission-critical, seal failure is simply not an option. Seal performance is key, even in extremely harsh environments that can destroy traditional polymer and elastomer seal solutions.

Many times, aerospace and defense engineers must achieve a balance between the friction of a seal and its sealing effectiveness. This can be difficult because friction increases power consumption which in turn can increase the fuel or power needed. A low coefficient of friction is a must for the seal jacket material used, especially if it is a dynamic seal of one that involves oscillating movements.

Applications that involve oscillation, such as pan/tilt, pod, and gimbal seals, must have both low friction but prevent stiction. Repetitive, precise, accurate movement has to be taken into account for some of these applications.

Aerospace and defense sealing environments often involve corrosive or reactive media that is not only dangerous if it leaks but can destroy the materials used for seals. Chemical compatibility and resistance to media such as fuels, oils, acids, bases, and other reactive chemicals is a must.

There is, however, another factor to be accounted for: abrasive media. Many seals are exposed to environmental contamination such as dirt, dust, sand, and other abrasive particles. An effective seal must not only be able to keep such contaminants outside, but not be destroyed in the process.

Extreme temperatures (and temperature ranges) can also pose a serious challenge. Applications can involve cryogenically cold temperatures down to -460°F to extreme heat at 600°F. And some operating environments may involve temperatures that vary widely, making dimensional stability a key element in seal design for aerospace and defense equipment. Temperatures are not the only environmental factor that can be extreme, however. Operating pressures can be extreme, ranging from 20 KSI to vacuum pressures.

Spring-Energized Seals for Aerospace and Defense

Spring-energized seals are highly reliable, even when things go wrong. They provide dependable performance in extremely harsh conditions, especially when the right seal jacket material is chosen.

Materials such as PTFE or PEEK have extremely low coefficients of friction and are self-lubricating. When combined with spring-energized seal design, the result is a low-friction seal that does not compromise the effectiveness of the seal and prevents potential issues with stiction and stick-slip behavior. These materials are also self-lubricating, making them ideal for situations where temperature or media rules out the use of traditional lubricants.

In addition, PTFE and PEEK are both highly resistant to chemical attack, with PTFE being the most chemically compatible polymer on the market. Combining the reliability of a spring-energized seal with the compatibility of materials such as PTFE or PEEK means a high performance seal that can survive in the presence of harsh media.

Spring-energized seals can account for seal wear and changes in the surface condition of the sealing surface without compromising the integrity of the seal. When combined with an abrasion resistant jacket material, they become an ideal sealing solution for applicants that involve abrasive media and contamination.

Both PEEK and PTFE can handle the extreme temperatures involved in aerospace and defense sealing applications. Not only do they possess a wide range for operating temperatures, they are also dimensionally stable. Dimensional stability combined with the ability of a spring-energized seal to account for dimensional changes make for an excellent sealing solution when there are extreme temperatures and wide temperature differentials involved.

Extreme pressures are another area where spring-energized seals outperform traditional seals. Whether its negative vacuum pressures or high 20,000 psi pressures, spring-energized seals can provide reliable performance — even when the environmental pressure varies significantly. Keep in mind that the spring-energizer keeps the seal lip in contact with the sealing surface.

Where Spring-Energized Seals Are Used

Spring-energized seals are already being used in landing gears, where they have proven invaluable for cylinders and hydraulic pumps. They offer the precision and performance needed for metering valves and fuel pumps, not to mention their use with actuators as they prevent environmental contamination. Spring-energized seals can also be found applications involving gimbals and pods, where their low coefficient of friction and self-lubrication prevents issues with sticking.

Conclusion

Spring-energized seals with PTFE or PEEK as the jacket material provide a high-performing solution to many sealing applications in the demanding environments of the aerospace and defense industries. Keep in mind that custom jacket profiles and spring-energizers can also be engineered to meet specific project needs and extensive testing can be performed to ensure that they are in compliance with related military standards.

by Jackie Johnson Jackie Johnson No Comments

The Oil and Gas Industry During Covid-19

During the early months of 2020, when the COVID-19 pandemic raged across the globe, the oil and gas industry face a historic collapse.

2020 was a year of astounding disruption.

With restrictions in travel, decline in economic activity, a price war between various countries, and declines in stock, the industry was shaken to its very core and, like many other industries, forced to reinvent itself in the wake of 2020.

In this week’s blog post we will discuss the state of the oil and gas industry during the COVID-19 pandemic, how it has fared, and innovations that have been made.

An Industry Wide Crisis

2020 was a volatile year for many industries, oil and gas in particular. In the early months of 2020, oil prices had declined by about 33%. After that various oil producing countries engaged in a price war, triggered by a breakdown in dialogue. COVID-19 caused a historic drop in travel, causing the demand for oil to plummet to unprecedented lows.

WTI spot prices declined to as low as $8.91 a barrel in April of 2020, a level not seen since the economic recession of 1986. The drop in oil prices has also added problems to several energy producing states and local governments in the US, such as Texas, that are dependent on oil and gas revenue.

Many companies had to reorganize their entire business model, and many others were forced to file for bankruptcies or to liquidate their assets.

Things looked fairly bleak for the industry as 2020 progressed and the pandemic continued to rage across the globe. Despite that there were several silver linings.

Oil in the Medical Market

One good thing is that despite the disruption in oil production, causing a drop of more than a million barrels per day over the year, there has been little to no shortage in actual supply of oil. This means that people have still been able to fill their car or use natural gas to heat their home. The industry has also been open during large parts of the pandemic, having been deemed essential by the government. This makes sense, as petroleum is used in everything from anesthetics to wheelchairs to the gas the powers ambulances.

Likewise, while there has been a shortage of medical supplies such as masks and ventilators, it was mainly a planning issue. These supplies and others like gowns, surgical equipment, syringes and more are made with petroleum-based products. As such the oil and gas industry was able assist to manufacture all of those products in mere weeks to meet the demands created by COVID-19.

Similarly, with the COVID-19 vaccines include syringes made from plastics derived from petroleum, and the Pfizer and Moderna vaccine require storage in industrial refrigeration made possible thanks to petroleum-based products.

Digitalization

While there is no doubt that COVID-19 has disrupted the oil and gas industry, some are stating that it may be a blessing in some ways. According to a report by the International Bar Association, the “reduction in oil and gas prices has increased the pressure on the industry to seek greater efficiency and reduce production costs.”

One promising alternative is digitalization, either through virtual modeling for project optimization, digital planning, cloud-based process design or machine learning.

With the social distancing requirements in place in many countries, this has forced companies to streamline remote work platforms.

Bob Benstead, VP of business cloud software firm Infor had this to say on the subject:

“I believe the biggest development that the oil and gas industry will see in 2021 will be the dramatic ramp-up of digital initiatives. This will truly push the industry toward new thinking, especially around how to maximize AI and machine learning, aligned to sensors and other Internet of Things devices, to drive down costs and optimize the workforce. Additionally, the increased trend toward cloud computing will help to significantly lower the total cost of service (TCS) to build, run and maintain efficient ERP (enterprise resource planning) and EAM (enterprise asset management) systems that oil and gas companies rely on.” (Rigzone.com “What Looms for Oil and Gas in 2021”)

Digitalization is expected to play a key role in the oil and gas industry as 2021 goes on. With enabling remote operations and allowing more human-machine collaboration, digitalizing is driving the industry forward.

Hope on the Horizon

The EIA (the US Energy Information Administration) predicts that the cost of crude oil will decline by the second half of 2021, making a more balanced global oil market. This will hopefully lower gas prices, which have been at record highs, as well as lowering the cost of production of petroleum-based products.

The oil and gas industry is also looking towards the future, with key players looking into clean energy transition, exploring public-private partnerships.

In early October, 323 rigs were working in domestic oil plays, which rose to 413 for the week ended Dec. 23, up about 28% year to date. This is still down substantially from the 838 rigs active in early March, but up nearly 50% from the early-July low of 279.

And finally, while the oil and gas industry as a whole has seen a downturn in profit, one sector, the gas pump market, as seen a CAGR growth of 6.85% in 2020, and is expected to reach a market size of US$8.685 billion by the year 2026.

In Conclusion

The impact of COVID-19 on the oil and gas industry has forced many to discuss the future of one of the world’s most volatile industries. Despite the hardships, however, there is no doubt that oil and gas will remain an important part in the global economy, and our every day lives, for some time to come.

For more information of polymer sealing solutions for oil and gas, contact Advanced EMC Technologies today!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Rotary Shaft Seals in the Oil and Gas Industry

Seals in the oil and gas industry face some of the most intense challenges, HPHT (High Pressure, High Temperature) and corrosive media. Trying to find the right rotary shaft seal for such an application can be challenging but is far from impossible.

Introduction to Oil and Gas Seals

Seals are needed in many different areas of the petrochemical industry. They can be found in compressors, motors, gearboxes, pumps, top drives, and steam turbines. Seals are required for mixers, extruders, fans, cooling towers, and blowers. Swivel stacks, wellhead connectors, subsea connectors, and rotary drill bits are also in need of reliable seals to do their job safely and effectively.

And whether these seals are for upstream, midstream, or downstream petrochemical processing, they often serve in a critical application: when a seal in the oil and gas industry fails, it is more than an inconvenience. Seals failures can quickly prove devastating to personnel, the equipment, and the environment. And the costs of seal failure can easily extend beyond equipment downtime and repair costs, as there may be fines related to environmental damage as well as costly lawsuits and out-of-court settlements involved.

With all that said, it can be agreed that seals for rotary shaft applications must be especially reliable, extremely rugged, and able to provide excellent performance in some of the most hostile operating environments in existence.

Spring-Energized Seals

Spring-energized seals include a spring energizer that keeps the seal lip in contact with the sealing surface when other seals would fail. They can maintain a seal even in the presence of wear, out of roundness, eccentricity, and runout. In addition, spring-energized seals outperform traditional lip seals in extreme pressures (including vacuum pressures) and extreme temperatures (including cryogenic temperatures). 

Most oil and gas applications using spring-energized seals take advantage of canted coil springs and their ability to provide a consistent load on the seal lip over a wide deflection range. In addition, canted coil springs are also highly resistant to damage unless they are stretched upon installation.

Labyrinth Seals

Labyrinth seals do an excellent job of sealing and are very effective at contaminant exclusion. They accomplish this through a barrier with a complicated set of maze-like paths (hence the term “labyrinth”) that (1) restricting the clearance through which leaks can occur and (2) creates areas of turbulent flow and high flow friction to further prevent leaks and contamination.  They are considered a dynamic mechanical clearance seal.

One of the benefits of labyrinth seals is their ability to provide sealing without making contact with the sealing surface. This means they experience far less wear than traditional lip seals and generate less frictional losses, as well. They are highly efficient, extremely reliable, and are even easy to install.

Seal Materials

Rotary shaft seals can be exposed to highly corrosive chemicals including methanol, H2S, aromatic hydrocarbons, oil, and supercritical CO2. Many of the chemicals that seals must interact with are also highly flammable gases and liquids. Operating temperatures can range from cryogenic below zero temperatures all the way up to 800°F, depending on the application and media involved. To complicate matters further, some liquid products are handled near their vapor temperature where they can unexpectedly flash into vapor. In addition, the materials used need to be resistant to chemical permeation while also being extremely wear-resistant and flameproof.

Two options typically lie at the top of the list for seal jacket materials: PEEK and PTFE. Both of these high-performance polymer materials are extremely compatible with a wide range of chemicals. They offer excellent performance in the HPHT environment found in most oil and gas applications: PEEK has a maximum operating temperature of  500°F and PTFE can handle temperatures up to 575°F. They also perform well in below-zero cryogenic temperatures, such as those used with LNG.

These engineering polymers are also wear-resistant and flame resistant with low coefficients of friction and thermal expansion. In addition, they are dry-running so no additional lubricants are required.  And PEEK in particular offers excellent performance even in sour gas environments, which often destroys other seal materials.

For spring-energized seals, both PEEK and PTFE are excellent choices. For labyrinth seals, however, PEEK or Flourosint (enhanced PTFE) usually performs more effectively. And keep in mind that these materials can be enhanced with fillers to increase their mechanical properties, including stiffness, strength, and wear resistance.

Conclusion

When traditional rotary shaft lip seals fail in oil and gas operations, consideration should be given to spring-energized seals and labyrinth seals combined with PTFE, PEEK, or enhanced PTFE. This combination of sealing technology and engineering polymers can provide the reliable performance needed in critical applications where seal failure is simply not an acceptable option. Both types of seals and the materials described here have proven performance records for their ability to handle the rugged, corrosive, HPHT environments of the petrochemical industry.

by Jackie Johnson Jackie Johnson No Comments

Fluoropolymers in the Food Industry

High-performance fluoropolymers are incredibly vital for use in food and drink manufacturing industries. Setting them apart from general-purpose plastic such as PVC and PE, fluoroplastics enjoy a range of unique properties:

  • Thermal: Resistant to very low and very high working temperatures
  • Chemical: Total resistance to chemicals and solvents
  • Mechanical: Low friction, non-stick characteristics and tensile strength
  • Environmental: Resistant to weather, UV light and corrosion
  • Health: Non-toxic and high purity

Fluoropolymers such as PTFE (Polytetrafluoroethylene), FEP (Fluorinated Ethylene Propylene) and PFA (Perfluoroalkoxy Alkane) bring an abundance of benefits to the food and drink production, from cooking equipment to food coverings, conveyor belt rollers, UV lamp coatings, temperature sensor casing and non-stick surface covers. Because of this, fluoropolymers have kept products uncontaminated, workers safe and production running smoothly for years now.

In this week’s blog post, we will discuss the various ways the fluoropolymers are used in the food industry.

Beverage Dispensing

The requirement for a biologically harmless tubing product coupled with intermittent high temperatures over a long period of time present a challenge for hot beverage dispensing machines. Fluoropolymers such as PTFE and FEP are used as a tried and tested, FDA, NSF and EU compliant solution. Build of residue is greatly reduced due to the smooth internal surfaces provided by fluoropolymer materials. Not only are they FDA compliant, but they are low maintenance as well!

Food Packaging

In packaging and processing food, it is extremely important that the materials used are safe. As such, fluoropolymers such as PVDF, or Polyvinylidene Fluoride Fluoropolymer, are highly regarded in the food packaging industry for a variety of reasons. First, they are incredibly stable materials, and highly resistant to most chemicals, mineral acids, organic acids and other food preservatives. In addition, they are non-toxic and resistant to bacterial and fungi growth.

PVDF is particularly useful in food processing industry due to its unique chemical resistance when temperatures go as high as 300 degrees Fahrenheit (or around 149 degrees Celsius).

PTFE Coatings

With the invention of PTFE, also known as Teflon, non-stick and low friction coatings have played a vital role across the food industry.

For years, PTFE has been used as a coating for cooking applications where particularly sticky or abrasive products are used, such as commercial waffle irons, bread pans, mixers and beaters, hoppers, dough rollers and blades. This allows them to function much more effectively, and the use of oils or other release agents can be substantially reduced or even eliminated.

With ease of use also comes ease of cleaning, and PTFE coating can reduce the intensity and frequency of the cleaning process. It also acts as a hygienic barrier between the food and the surface of the component. These combined save significant employee time and effort, which ultimately reduces labor costs, saving both time AND money.

Belt Conveyors

In the cooking and food processing industries, belts and conveyers made with PTFE coatings are used for mass-produced foods such as bacon, chicken, hamburgers and eggs.

Because of its nonstick properties, the PTFE coating allows food to easily come off, with little mess. This facilitates a high volume of production for commercial food processors.

Industrial Bakeware

Fluoropolymer coatings assure high-quality coating solutions for bakeware used by industrial bakeries. This helps bakeries not only drive efficiency, but also improve the hygiene and safety of their operations. It also improves the quality of the final baked product, with less waste and less butter and/or grease used to keep the product from sticking to the pan.

Home Cookware Manufacturing

We have talked about how fluoropolymers are across the commercial industry, but they are just as equally prevalent in our homes as well.

The use of nonstick pans has been popular in homes since the 1950s, when a French engineer begun coating his fishing gear with Teflon to prevent tangles. His wife then suggested using the same method to coat her cooking pans. In 1956 the Tefal company was formed and began manufacturing non-stick pans.

And nonstick cookware is popular to manufacture as they can be machined and coated relatively easily.

Other Uses

As discussed, fluoropolymers have many uses in the food industry, and many more that we did not cover. Some of these include

  • Shatterproof Coatings for Heat Lamps
  • Encapsulated Temperature Sensors
  • FEP Roll Covers
  • Laser Marked and Printed Tubes for Identification
  • And more!

In Conclusion

With the strength and versatility of fluoropolymers, it is no wonder that it is such a popular material within the food and drink industries.

Because of its high temperature and chemical resistance, nonstick and non-toxic surface, many health organizations have recognized it’s inherit value and, as such, have made fluoropolymers the gold standard within the food industry.

To learn more about fluoropolymers, visit our page by clicking the link here. And if you need PTFE sealing solutions, contact us today!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Spring-Energized Seals for the Food and Dairy Industries

The food and dairy industries are tough on seals, whether its extreme pressures and temperatures or the limitations posed by using only FDA-approved materials. Spring-energized seals, however, can prove an excellent solution for the challenges posed by these industries. In this week’s blog post, we will discuss spring energized seals in the food and dairy industries. 

Issues for Seals in the Food and Dairy Industries

There are several key issues involving seals for the food and dairy industries. The most obvious is FDA approval, but these seals are also exposed to both extreme temperatures and high pressures. Sanitation procedures are extremely harsh, often involving steam, hot water, and aggressive chemicals to achieve hygienic conditions. In addition, the seals will often be exposed to water for extended periods of time, which could be absorbed by the seal material and result in compromising dimensional changes. Lubrication can also be an issue, which means seals may have to be self-lubricating. Finally, the seals must be reliable, able to perform in less than ideal circumstances.

Spring-Energized Seals

Unlike traditional seals, spring-energized seals include an energized seal provides permanent resilience to the seal jacket. The energizer compensates for hardware misalignment, jacket eccentricity, and wear. These seals are typically made of strong, corrosion-resistant stainless steel with a polymer jacket.

FDA Approved Materials

FDA CFR 177, contained in Title 21 of the Code of Federal Regulations, deals with indirect food additives (i.e., substances that inadvertently make their way into food) in the form of polymers. In addition to FDA regulations, there are other standards in place that apply, including (EU) 1935/2004, NSF/ANSI standard 61 for drinking water systems, and 3A Dairy sanitary standards 18-03 and 20-27.

Spring-energized seals are available in materials that are FDA approved. These materials include UHMW PE (Ultra High Molecular Weight Polyethylene) and PTFE (both virgin and certain grades of mineral-filled) and are both known for low friction, chemical inertness, and the ability to handle rugged sterilization and cleaning procedures that can involve steam, hot water, and aggressive chemicals. Other polymers that might be considered  dependent on the application are certain grades of PEEK and Acetal. In addition, UHMW PE, PTFE, and Acetal are also 3A-Dairy and USDA compliant.

Extreme Temperatures and Extreme Pressures

Food and dairy seals must provide reliable performance in extreme pressures and temperatures. Spring-energized seals are able to maintain a tight seal in temperatures and pressures that would cause more traditional seals to fail. This is primarily due to the spring-energizer that keeps the seal lip intact regardless of dimensional changes due to temperature variation as well as pressure fluctuations. Spring-energized seals are well known for their sealing ability at extreme pressures, including vacuum pressures. In addition, they work extremely well in cryogenic temperatures.

Sanitation Procedures for the Food and Dairy Industries

Food and dairy applications almost invariably involve harsh sanitation procedures that can compromise the performance of typical seals. For example, steam and hot water can cause a significant temperature difference, but the spring-energizer is able to maintain a positive seal even if the seal lip changes dimensions. The right choice of an FDA-approved material can ensure that the seal jacket will remain undamaged in the presence of any aggressive chemicals used. 

Hygroscopic Effects

When seals are exposed to moisture, water, or humidity for extended times, the seal jacket material may absorb that moisture. This can lead to dimensional changes that compromise the performance of the seal. However, with a spring-energized seal, the energizer allows the seal to maintain contact regardless of those dimensional changes. And with a material such as PTFE or UHMW PE for the seal jacket, the possibility of moisture absorption and associated hygroscopic effects is further reduced.

Lubrication

In food and dairy applications, it may not be possible to lubricate seals because of the possibility of contamination. Choosing the right FDA-approved material for a spring-energized seal can eliminate the need for a lubricant because both UHMW-PE and PTFE are dry running, self-lubricating materials.

Reliable Performance

Seals are critical in food and dairy processing: a failed seal can contaminate goods and, if undetected, can put consumers in danger. Spring-energized seals are extremely reliable, both for the reasons already discussed as well as their ability to compensate for issues such as wear, out-of-roundness, eccentricity, and issues with the surface of the shaft. These seals can perform where traditional seals would fail, again thanks to the spring-energizer that keeps the lip of the seal in contact with the shaft. 

Additional Benefits of Spring-Energized Seals

Spring-energized seals can also be used as direct replacements for traditional seals that have failed, even for failures. Because of their durability and resistance to corrosion and contamination, spring-energized seals last longer which in turn leads to reduced downtime and repair costs.

Conclusion

Spring-energized seals are needed in various applications related to the food and dairy 

Industry, including blenders, homogenizers, mixers, process vessels, and hygienic piping systems. For reliable, durable, high performing seals for the food and dairy industries, consider the use of spring-energized seals.