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4 Common PTFE Characteristics

PTFE, commonly known as Teflon, has revolutionized various industries with its unique properties and versatility. This article will explore PTFE characteristics and its applications in different fields.

PTFE Characteristics

PTFE is a synthetic fluoropolymer discovered by accident in 1938 by a chemist named Dr. Roy Plunkett at DuPont. He was experimenting with refrigerants when he stumbled upon this remarkable material. It was in the 1940s that DuPont began commercial production of PTFE under the trade name Teflon.

PTFE Characteristics: Low Friction

One of the most well-known PTFE characteristics is its low friction. This attribute has made it incredibly popular in applications where reduced friction is critical, such as non-stick cookware and bearings for machinery. The low-friction property allows objects to slide smoothly over surfaces coated with PTFE without resistance or sticking.

In addition to its low-friction quality, PTFE also possesses excellent sealing properties, making it an ideal choice for gaskets and seals. Its high melting temperature ensures it can withstand extreme heat without deforming or losing its sealing capabilities. Moreover, PTFE exhibits exceptional resistance to corrosion from chemicals and solvents, making it suitable for use in harsh environments where other materials would fail.

Long Product Life

Another advantage of PTFE is its resilience and long product life. Due to its high molecular weight and carbon-fluorine solid bonds, this material can withstand repeated compression cycles without losing its shape or effectiveness as a sealant. This longevity ensures that seals made from PTFE maintain their integrity over extended periods, reducing maintenance costs for industries relying on these components.

A critical property of PTFE relevant to sealing materials is its lack of “memory.” Memory refers to a material’s tendency to return to its original shape after deformation or compression. In contrast, when pressure is applied to a PTFE seal, it exhibits material creep, which conforms to the mating surface and creates a secure seal. This unique behavior ensures that PTFE seals adapt to irregular surfaces and maintain their sealing capabilities even under varying conditions.

PTFE Characteristics: Chemical Resistance

PTFE’s chemical resistance is also suitable for lining pipes and tanks in corrosive environments such as chemical plants or wastewater treatment facilities. The non-reactivity of this material ensures that no contamination occurs when transporting aggressive chemicals through these pipelines.

Moreover, the versatility of PTFE extends beyond traditional applications. In recent years, researchers have explored new possibilities for this synthetic fluoropolymer. For instance, PTFE-based nanoparticles have shown potential in drug delivery systems, where they can encapsulate medication and release it slowly over time.

Stringent Regulatory Requirements

Furthermore, PTFE meets stringent regulatory requirements set by organizations such as the FDA (Food and Drug Administration) and AMS (Aerospace Material Specification). It conforms to these standards regarding material thickness, ensuring its suitability for use in industries like medical and food production. The FDA-approved PTFE can be safely used in applications where direct contact with food or medicine is necessary.

The medical industry has greatly benefited from the properties of PTFE. Its biocompatibility makes it an excellent choice for implants, prosthetics, and other medical devices. Due to its low-friction characteristic, PTFE-coated catheters reduce discomfort during insertion into blood vessels or other body cavities.

Similarly, the food production industry relies on PTFE for various applications. Its non-stick property allows the easy release of food products from molds or cooking surfaces without leaving any residue behind. PTFE’s resistance to high temperatures also ensures it can withstand the heat generated during cooking without degrading or releasing harmful substances.

In addition to its applications in sealing materials, cookware coatings, and biomedical devices, PTFE also finds use in numerous other fields. It is widely used as insulation for wires and cables due to its excellent electrical properties. The low dielectric constant of this material prevents energy loss through heat generation or leakage currents.

In conclusion, PTFE or Teflon is a remarkable synthetic fluoropolymer that offers a wide range of valuable properties. Its low-friction characteristic and sealing capabilities make it indispensable in manufacturing, food production, and medical devices. The resilience and longevity of PTFE ensure its effectiveness even under extreme conditions. We can expect more innovative applications for this versatile material as technology advances.

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The Versatile Use of PTFE Plastic in Technology and Food Industry

The world of technology and industry has been revolutionized by using PTFE plastic. This highly versatile material is known for its excellent chemical resistance, great thermal and electrical insulation properties, and low friction. PTFE is a soft fluoropolymer plastic that can easily withstand high temperatures, making it ideal for various applications.

PTFE Plastic

PTFE plastic is used in several industries, including electronics, aerospace, automotive, and medical equipment manufacturing. For instance, due to their low friction properties, PTFE is widely used to make bearings resistant to corrosion and wear. It also makes an excellent insulation material due to its thermal stability of up to 500°F.

PTFE Plastic in Food Industry

Another significant application of PTFE is in the food industry. Its non-stick properties make it ideal for cookware coating and other food processing equipment such as conveyor belts; this reduces the amount of oil required during cooking and prevents food from sticking onto surfaces.

Laboratories

One key benefit that sets PTFE apart from other plastics is its chemical inertness; it does not react with most chemicals or substances, making it safe for use in sensitive environments such as laboratories where purity levels are critical.

PTFE tubing also plays a vital role in many laboratory applications since it can resist harsh chemicals like acids without breaking down or reacting with them. This characteristic makes it invaluable when working with hazardous materials or conducting experiments where accuracy is paramount.

Electrical 

In addition to being chemically inert and thermally stable up to 500°F (260°C), PTFE has superior electrical insulating properties, making it useful for electronic applications. It resists moisture penetration better than most plastics while maintaining its insulating qualities over an extended period; this property makes parts made out of this material last longer than those made out of other materials like nylon or PVC.

Aerospace and Automotive PTFE Plastic

PTFE plastic is also used in the aerospace industry due to its light weight and ability to withstand high temperatures. It is often used as a coating for parts that experience friction or heat, such as engine components, gears, and bearings. This application of PTFE has helped reduce aircraft weight while increasing their durability.

In automotive manufacturing, PTFE plays a critical role, too; it helps make brake systems more effective by reducing wear on parts that would otherwise cause issues like brake squeal or vibration. This material also reduces fuel consumption by making engines run more efficiently with less friction between moving parts.

Medical Equipment

Medical equipment manufacturers have found PTFE plastic helpful in creating devices that require high levels of purity and chemical resistance. For instance, catheters made from this material can resist bacterial growth while maintaining flexibility; this makes them ideal for use in sensitive applications such as cardiac surgery, where contamination could lead to severe complications.

The versatility of PTFE plastic is enormous; it can be molded into different shapes suitable for various applications. It can also be blended with other materials, such as glass fibers, to increase its strength or pigments to give it color without affecting its properties significantly.

In conclusion, the versatile use of PTFE plastic in technology and food industries cannot be overstated. Its unique combination of thermal stability up to 500°F (260°C), excellent electrical insulating properties, and non-stick surface, which makes it ideal for cookware coating and chemical resistance, has made it an essential component in several sectors worldwide. As research continues into this unique material’s properties, more applications will undoubtedly emerge, making our lives easier and enhancing product performance across various fields.

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How Canted Coil Springs Provide EMI/RFI Protection

Canted coil springs

The rise of technology has brought about a new era of innovation and efficiency in the modern world. With the advancement of electronic devices, there has been an exponential increase in the number and type of gadgets we use daily. Electronics have become integral to our lives, from smartphones to computers, cars to airplanes. However, with this increase in usage comes a corresponding increase in electromagnetic interference (EMI) and radio frequency interference (RFI). EMI/RFI can cause significant harm to sensitive electronics resulting in malfunctioning or failure. Canted coil springs can be a way to protect equipment from EMI/RFI interference.

Canted Coil Springs as EMI Shielding

Shielding sensitive electronics from EMI/RFI is thus an essential requirement for any electronic device manufacturer. Various shielding solutions, like metal shields or coatings, often suffer from weight, thermal management problems, and low flexibility.

This is where canted coil springs come into play. These springs provide superior EMI/RFI shielding while being lightweight and flexible. The unique design features independent coils that serve as multiple contact points for optimal conductivity and/or grounding, ensuring consistent, reliable connection with mating surfaces under shock and vibration.

The precisely engineered coil angles ensure that these springs provide maximum surface area contact, resulting in efficient current transfer and decreasing contact resistance between mating surfaces. This feature leads to less energy loss due to heat dissipation than traditional designs, translating into better performance over time.

Canted coil springs are made using various materials, including stainless steel alloys capable of handling high temperatures without losing shape over time, ensuring longevity even under harsh operating conditions.

Applications as EMI Shielding

These unique springs can be used for applications ranging from medical equipment to aerospace systems, where reliability is paramount. One such example is their use as connectors between motherboard components on computers, where they reduce the noise created by signal transference between components leading to improved overall system performance.

Canted coil springs can also be used as cable shielding, providing flexible, lightweight, and low-resistance solutions for high-speed data transmission cables. They are especially useful in applications where weight is critical, like aerospace or automotive.

Advantages of Canted Coil Springs

An advantage of these springs is their ability to absorb shock and vibration, reducing the risk of damage to electronics due to mechanical stress over time. This feature makes them ideal for use in rugged environments such as military applications, industrial machinery, or heavy-duty vehicles.

In addition, canted coil springs are easy to install and require no additional hardware making them a cost-effective solution for manufacturers. They can be easily integrated into existing designs without redesigning entire systems, thus reducing development costs while still providing superior performance.

Overall, canted coil springs offer an excellent solution for EMI/RFI shielding needs with their superior conductivity, flexibility, and shock absorption capabilities, all while being lightweight and easy to install. Their versatility makes them an excellent choice for almost any application where reliable electronic performance is essential.

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Expanded PTFE vs. PTFE

expanded PTFE

Polytetrafluoroethylene (PTFE) is one of the most common materials used for seals. Expanded PTFE, or ePTFE, is a soft material with many of the same properties as PTFE. However, ePTFE is more flexible, making it a better choice for specific applications.

How does ePTFE compare to PFE? For better clarification, let’s look at some of the aspects of the two.

What is Expanded PTFE

Expanded Polytetrafluoroethylene (ePTFE) is a PTFE resin created through a unique processing method that includes stretching, making it flexible. Expanded PTFE has a mesh structure ideal for medical equipment, food processing, oil and gas, and any other industry requiring tight seals.

Like its counterpart PTFE, ePTFE is non-toxic, hygienic, and chemically inert. In addition, its flexible nature allows it to seal tightly over surfaces where traditional seals won’t work. 

Advantages of ePTFE 

Expanded PTFE has high sealability, especially at low stress. It can compensate for irregularities in the surface to create a steadfast seal. The ePTFE gasket sheets have superior resistance to creep and cold flow and adapt well to sealing surfaces.

Applications ePTFE 

The ePTFE gasket sheets have a porous nature making them ideal for use in medical devices. For example, it is found in dental implants and barrier membranes in medical equipment. It is also found in electronic insulators and high-performance filters.

The oil and gas industries use ePTFE sheets to even out bumps and ridges in chemical pipe flanges. Smoothing out the bumps helps to provide a tighter seal between the flanges for better leak control.

Other applications for ePTFE include:

  • Pumps
  • Glass-lined flanges, reactors
  • Heat exchangers
  • Apparatus constructions

Properties of ePTFE 

ePTFE is 100% multidirectional and is physiologically inert for all recommended applications. Other technical properties of ePTFE sheets include the following:

  • Chemical resistance in the entire pH range (except for molten alkali metals)
  • Temperature Range: -268°C to 270°C (-450°F to 518°F).
  • Density of 0.85g/cm3 +/- 0.10g/cm3 
  • Pressure range of vacuum up to 200bar (3000psi)

What is PTFE

Polytetrafluoroethylene (PTFE), also known by its trade name Teflon®, was discovered in the 1950s by Dupont Chemist Roy J. Plunkett. It is a non-wetting, high-density material that is resistant to high temperatures.

Because of its high melting point and insolubility in most solvents, PTFE is the ideal choice for most sealing applications. In addition, PTFE can be unfilled (virgin) or filled with various compounds, such as glass or carbon. 

Advantages of PTFE 

Using PTFE as a seal or gasket has many incredible advantages. These benefits make it the ideal choice for applications across many fields. Let’s take a look at some of those advantages. 

PTFE has a high-temperature resistance. PTFE can withstand temperatures of up to 500°F or 260°C. In addition, PTFE is chemically resistant to aggressive chemicals such as solvents, acids, and bases. 

Along with its temperature and chemical resistance, PTFE has non-corrosive properties and can be used as electrical and thermal insulation. This versatile material comes in a wide range of thicknesses, fillers, and compressed sheets.

Applications PTFE 

There are several applications in which PTFE is the ideal sealing solution. Industrial plants use PTFE as envelope gaskets to contain leakages of the substances being managed. The substance’s water resistance makes it suitable for industrial plants, the food industry, and medical laboratories.

PTFE is also used in construction because of its low frictional quality, which extends the life of the PTFE. The sheets are also used in industries where highly reactive substances because of the sheet’s resistance to acids. 

Properties of PTFE 

PTFE’s low coefficient of friction is not the only property that makes it ideal for many sealing applications. Other properties include:

  • A density of 2.10e3 – 2.2e3 kg/m3
  • Tensile strength is 2.07e7 – 3.45e7 Pa
  • Max Temperature 250°C to 271°C (482°F – 520°F)
  • Melting Temperature 215°C – 339°C ( 599°F to 642°F)
  • Chemical resistance to the entire pH range (except for molten alkali metals)

Conclusion

Both ePTFE and PTFE are suitable for most sealing applications. Determining which product is necessary depends on the application. Contact us today to learn more about our PTFE sealing options.

by Denise Sullivan Denise Sullivan No Comments

Ball Valve Components: What Are They

ball valve components

Ball valves are designed to control flow by rotating an internal ball within a housing. They’re often used for applications where there’s a need to regulate pressure, temperature, or flow rate.

A ball valve has two main parts: a body with a central opening and a ball that fits into the opening. As the ball rotates, it opens or closes the valve. In addition to the main parts, ball valves have different internal components that help them work in different environments. Standard ball valve components include:

  • Chevron packings
  • O-rings and backup rings
  • Floating seats
  • Inserts

Keep reading to learn more about these components.

Chevron Packings

Chevron packings are also called v packing or vee packing seals. These seals automatically react to changes in pressure. Multiple chevron seals are used together to form the overall seal. While these seals have a v-shape, they are shipped with a male and female adapter to provide a flat surface rather than the v-shape.

Chevron ball valve components work well at sealing fluid in centrifugal, static, and reciprocating environments. They are recommended to reduce pressure and avoid shrinkages in the presence of linear or rotary movement. 

These seals are manufactured in virgin PTFE, modified PTFE, and glass or carbon-filled PTFE. While virgin seals are ideal for many conditions, filled compounds are recommended for most applications. Your provider will recommend the optimum PTFE compound.

O-Rings and Backup Rings

O-rings are a standard ball valve component. They are used whenever soft sealing is required to help prevent extrusion. The design of these seals allows them to be used in harsh conditions and with aggressive chemicals.

The o-rings found in ball valves are often used with backup rings. They can be made from neoprene, silicone rubber, polyurethane, and PTFE. The precise material will depend on the application and environment that the seal is employed.

Backup rings are circular sections, which may be cut or uncut, that help prevent the extrusion process. These are employed alongside o-rings or lip seals when couplings are not suitable.

Floating Seats 

A floating ball valve is one where the seat holds the ball in place while it floats around in the valve body. Pressure from the gas or liquid helps to push the ball against the downstream seat to form a tight seal.

Floating seats are used in several applications, such as oil and gas, cryogenic,  heating, and pharmaceuticals. However, they are most commonly found in hydraulic systems. The type of polymeric material used in these seats depends on maximum pressure, working temperature, or the type of gas or fluid it regulates.

Inserts

Like o-rings, inserts are in seats with soft sealing. This gasket can be manufactured from several different thermoplastic materials depending on its conditions. 

For example, virgin PTFE seals are unsuitable for butadiene or styrene service. PEEK material is not resistant to nitric acid or sulphuric acid. However, filled PTFE works well in high temperatures and low pressures, while PCTFE is ideal for cryogenic applications.

Conclusion

Ball valve components help to ensure the valves seal correctly. Depending on the valve application, these components can include o-rings, backup rings, chevron packing, inserts, and floating seats. 

Finding the appropriate seal inserts and materials can be challenging. Contact us today for help determining what best suits your application.

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5 Common reasons of Valve Seat Failure

valve seat failure

 

Valve seat failure can lead to costly and time-consuming issues. Under certain circumstances, a ball valve seat failure can cause explosions and lead to life-threatening situations. In this article, we will cover the top five causes of failure.

Material Choice

The material choice of the valve seat can contribute to valve seat problems if you pick the wrong option. Different materials work in different operating conditions, so you want to ensure that you research the material carefully before choosing.

The most common material options are 

  • PEEK
  • PTFE
  • TFM
  • PCTFE
  • Acetal
  • Vespel

The wrong material can cause unexpected issues that may damage the hardware of mating components or even physical injury.

Cold Flow

While PTFE, or Teflon, is a common material in valve seats, there could be some cold flow resistance issues. Cold flow is the process when solid material slowly deforms under the influence of long-term mechanical stress.

The cold flow of material during us and cycling causes a slow deterioration in valve performance. Despite cold flow issues, PTFE is still the best choice in many industries. Choose a filled PTFE instead of virgin PTFE to mitigate complications from cold flow. Filled is less susceptible to stress and has better resistance to cold flow.

Excessive Friction

Excessive friction can also cause valve seat issues. Excessive circumferential seal force accelerates wear on the valve, which leads to an increase in torque requirements. The friction between the ball and the valve seat affects how much torque is necessary to turn the ball valve. 

 When the temperature in the valve increases, the pressure between the valve seat and the ball increases. Increased temperature creates greater friction between the valve ball and the seat. 

Eventually, the valve can become locked either open or closed. As the required torque increases, the valve seat is torn apart, and mechanical failure occurs.

Valve Seat Failure: Seat and Seat Carrier Design

The valve seat is one of the most critical components. However, poor seat design can lead to a shortened lifespan, leakage, or catastrophic failure. The catastrophic failure could lead to explosions or life-threatening damage in particular environments.

Soft seat valves typically use metallic seat carriers with the valve seats pressed into them. As with the seat design, the seat carrier design can have similar problems. If the seat carrier design is slightly off, it could make it difficult to determine where the problem lies.

Permanent Deformation

In high-pressure applications, the valve setting of soft seats is necessary. To correctly set soft seals, the valve is repeatedly actuated during part of the build process. This repeated actuation can cause permanent deformation during normal use.

A failure to understand the initial deformation will cause the valve to fail. It won’t fail on initial use, but it will eventually stop working, and the valve will either need to be rebuilt or replaced as a result.

Valve Seat Failure Conclusion

Whether your valve requires PTFE, PEEK, or any other material, you want to ensure you get the appropriate material for your valve seat. Incorrect materials and excessive friction, seat design malfunctions, and permanent deformations can cause failures. 

Contact us today to learn more about the valve seats we offer and assist you in finding the appropriate material for your applications.

 

by Denise Sullivan Denise Sullivan No Comments

Virgin Teflon Balls vs. Glass-filled Teflon Balls: What You Need to Know

virgin teflon balls

At first glance, it might appear that the Teflon Balls are the same as the glass-filled ones. However, closer inspection reveals that the two materials have very different properties. Both virgin Teflon balls and glass-filled Teflon balls have unique properties, making them ideal for different applications.

This article will explore the differences between virgin and glass-filled Teflon balls.

Virgin Teflon Balls

Virgin Teflon balls can be either hollow or solid. Both offer the benefits of being lightweight and ideal for light load-bearing applications. These balls do not require lubrication and, unlike metal balls, are not magnetic and provide heat and electrical insulation.

The strengths of virgin Teflon balls include:

  • Weathering resistance
  • Solid PTFE balls are resistant to corrosion
  • Chemically resistant to all common solvents
  • Thermal resistance
  • Low smoke and toxic gas emissions
  • Abrasion, fatigue, and radiation resistant
  • Can be used in extreme conditions

 Applications

There are several applications in which virgin Teflon balls are the ideal choice. As it is ideal for light load-bearing applications, it is ideal in pump and valve components. Thanks to its electrical insulation properties, it is often used in electrical components.

Other applications where virgin Teflon balls are used include:

  • Sealing
  • Bushing
  • Food processing 
  • Medical device components

Properties

Virgin Teflon balls are generally white or off-white in color. In their natural state, Teflon balls are heavier than water. Other properties include 

 

Properties Unit Method Typical Value
PHYSICAL
Density g/cm3 ASTM D792 2.14-2.18
Hardness points ASTM D2240 51-60
Tensile Strength MPa ISO 527 ≥ 20
Elongate at Break % ISO 527 ≥ 200
Compressive strength at 1% deformation psi ASTM D695 580-725
Impact strength Izod J/m ASTM D256 153
TRIBOLOGICAL
Dynamic Coefficient of Friction / ASTM D1894
ASTM D3702		 0.06
Wear Factor K / ASTM D3702 2.900
PV limit at 3 m/min

             at 30 m/min

             at  300m/min

 N/mm2 * m/min / 2.4

4.2

5.7
THERMAL
Service Temperature °F / -328/+500
Thermal expansion coefficient (linear) 25-100°C 10-5 in/in/°F ASTM D696 6.625-7.206
ELECTRICAL
Dielectric strength  (specimen 0.5mm thick) KV/mm ASTM D149 ≥ 40
Dielectric Constat at 60 Hz and 106 Hz / ASTM D150 2.05-2.10
Volume Resistivity Ω * cm ASTM D257 1018
Surface Resistivity Ω ASTM D257 1017

 

Glass-Filled Teflon Balls

Glass is one of the most common fillers in filled Teflon balls. The filling typically ranges from 5 to 40%. Typically glass-filled Teflon balls are used instead of virgin Teflon balls because these components are stronger, and their compression and wear properties are an improvement.

The strengths of glass-filled Teflon balls include

  • Improved resistance to wear over standard solid PTFE balls
  • Resistant to oxidation and acid
  • High hardness rating
  • High maximum operating temperature
  • Increased compressive strength
  • Low coefficient of friction
  • HIgh UV Light resistance
  • Lower thermal expansion
  • Lower deformation under load

Applications

As with virgin Teflon balls, glass-filled PTFE can be used in many different fields. Some of the more common applications include

  • Petrochemical application
  • Commercial application
  • High-load industrial applications
  • Material handling
  • Precision part manufacturing 
  • Chemical engineering applications

Properties

The properties of glass-filled, carbon-filled, stainless steel, and bronze vary slightly. Understanding the difference will help you know which product is the best choice for each application.

For 25% glass-filled Teflon balls, typical properties include:

Properties Unit Method Typical Value
PHYSICAL
Density g/cm3

lb/in3

 ASTM D792

ASTM D792

 2.25

0.081
Hardness / ASTM D785 Shore D60
Tensile Strength psi ASTM D638 2100
Elongate at Break % ASTM D638 270
Compressive strength  psi ASTM D695 1000
Flexural strength psi ASTM D790 1950
TRIBIOLOGICAL
Dynamic Coefficient of Friction / ASTM D1894

 0.5
Static Coefficient of Friction / ASTM D1894 0.12
THERMAL
Maximum Continuous Operating Temperature °F

°C

 / 260

500
Minimum Continuous Operating Temperature °F

°C

 / -200

-328
Melting Point Temperature °F

°C

 ASTM D3418

ASTM D3418

 635

335
Thermal expansion coefficient (linear) 25-100°C 10-5 in/in/°F ASTM D696 6.4
ELECTRICAL
Dielectric fACTOR AT 1MHz / ASTM D150 2.4
Dielectric Constant at 1 MHz / ASTM D150 0.05
Surface Resistivity Ω * cm ASTM D257 >105

 

15% glass-filled Teflon balls properties are:

Properties Unit Method Typical Value
PHYSICAL
Density g/cm3

lb/in3

 ASTM D792

ASTM D792

 2.15-2.25

0.0777-0.0813
Hardness / ASTM D2240 60-64
Tensile Strength psi ASTM D638 2490-3700
Elongate at Break % ASTM D638 250-280
Compressive strength  psi ASTM D695 853-925
Impact strength Izod J/m ASTM D256 14.0-15.5
TRIBIOLOGICAL
Dynamic Coefficient of Friction / ASTM D1894

 0.060
Static Coefficient of Friction / ASTM D1894 0.050
THERMAL
Maximum Continuous Operating Temperature °F

°C

 / 518

270
Minimum Continous Operating Temperature °F

°C

 / -436

-260
Thermal expansion coefficient (linear) 25-100°C 10-5 in/in/°F ASTM D696 8.9-12.7
ELECTRICAL
Dielectric factor at 1MHz kV/mm ASTM D149 16.0-19.0
Dielectric Constant at 1 MHz / ASTM D150 2.3-2.5
Surface Resistivity Ω * cm ASTM D257 >1015

 

10% carbon filled

Properties Unit Method Typical Value
PHYSICAL
Density g/cm3

lb/in3

 ASTM D792

ASTM D792

 2.25

0.081
Hardness / ASTM D785 63
Tensile Strength MPa ASTM D1457 15
Elongate at Break % ASTM D1457 180
Compressive strength  MPa ASTM D695 100
TRIBIOLOGICAL
Dynamic Coefficient of Friction / ASTM D1894

 0.12-0.14
Static Coefficient of Friction / ASTM D1894 0.14-0.16
THERMAL
Maximum Continuous Operating Temperature °F

°C

 / 260

500
Minimum Continuous Operating Temperature °F

°C

 / -200

-328
Melting Point Temperature °F

°C

 ASTM D3418

ASTM D3418

 635

335
Thermal expansion coefficient (linear) 25-100°C 10-5 in/in/°F ASTM D696 9.5 x 10-5
ELECTRICAL
Dielectric factor at 1MHz / ASTM D150 –
Dielectric Constant at 1 MHz / ASTM D150 –
Surface Resistivity Ω * cm ASTM D257 >103

 

Bronze filled (40%) PTFE balls have a specific gravity of 3.0-3.12g/cm3 and a tensile strength of 22-27 Mpa, with a hardness of 65-68. Stainless steel-filled PTFE has a specific gravity of 3.35 g/cm3, a tensile strength of 22 Mpa, and a harness of 65-69.

Which Is Best?

Both virgin and glass-filled Teflon balls have their benefits. The ultimate choice of which ball you should use depends on the environment you are working in and your basic equipment needs.

Ready to learn more? Contact us today to learn about the types of Teflon balls we offer and which choice best meets your needs.

 

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High Performance Electric Vehicle Seals

electric vehicle seals

 

There is a push for more people to drive electric vehicles. While they are more environmentally friendly, the motors differ significantly from traditional combustion engines. Electric vehicle seals must keep lubrication confined to the gearbox, dirt, and debris out of the motor while providing engine efficiency.

In this article, you will gain a basic understanding of

  • How electric vehicles and internal combustion engines differ
  • Design considerations for electric vehicle seals
  • Types of materials used in making seals for electric vehicles

Differences in Electric Vehicle and Internal Combustion Engines

If you are standing outside an electric vehicle looking at it, you may not notice many differences between it and a gas-powered automobile. The overall external design is the same, except the electric car has no exhaust pipe.

However, below the surface, the two engines are significantly different. Gas-powered have a gas tank, gas pump, motor, carburetor, alternator, smog controls, and hundreds of other moving parts. In addition, the engine requires seals to keep oil and other fluids from leaking out. 

An electric vehicle engine only has one main moving part: the motor. Despite the motor being in a dry environment, seals are still required to help keep dirt and dust out of the engine and the lubricants needed for the vehicle gearbox. 

Both electric vehicles and internal combustion engines require specialized seals to keep the motors/engines working efficiently.

Electric Vehicle Seal Design Considerations

Electric vehicle motors work more efficiently and require seals that can handle their unique needs. The seals used in electric vehicles often exceed the minimum requirements of seals found in internal combustion engines. In addition, many of them must work in dry environments.

Friction

Friction is one of the primary design considerations for electrical vehicle seals. While friction in any engine is not desired, electric vehicles need a lower friction seal than traditional gas-powered engines. Any friction created by seals causes efficiency loss in power output. 

If the engine isn’t efficient, the battery won’t be able to have the range that it should. A motor working harder to make up for the efficiency loss won’t be able to travel as far as it should. Lower friction is essential to gain better efficiency and long distance. 

Dry Running

Electric vehicles require both dynamic and static seals. The dynamic seals are often called rotary lip seals.  While they don’t require oil seals, electric motors need seals that work in a dry-running environment. 

The primary shaft uses a rotary seal to prevent dirt, dust, and water from entering the electric motor. If fluid and debris enter the motor, it can damage the engine and cause it to break down or damage some of the highly charged electrical components so that it won’t work efficiently.

In addition to running in a dry environment, the rotary seals must withstand the higher speeds electric motors run. The components spin up to 18,000 rpm, about three times faster than a traditional combustion engine. As a result, seals in these engines have to withstand high-speed running without lubrication.

Electric Vehicle Seal Materials

Not all materials common seal materials work well in electric vehicles. However, two of the more common types are PTFE and molded rubber. The materials are used for different applications but are necessary as part of the vehicle’s makeup.

PTFE Seals

Polytetrafluoroethylene (PTFE), more commonly known as Teflon, is a nonreactive material with a low coefficient of friction. Therefore, it is ideal for high-temperature environments found in an electric vehicle motor.

Seals made from PTFE are usually found on the e-axle and help to act as a barrier between the motor and gearbox. The engine is a dry environment, while the gearbox requires lubrication. The PTFE seal keeps lubricant from seeping into the motor. In addition, the seal’s dry side has a lip that keeps dust and dirt out of the engine.

In addition to keeping the lubricant in the gearbox and dirt out of the motor, the PTFE rotary seal can withstand the high speeds in the car’s engine. Additionally, it provides low friction to keep the motor running efficiently.

Molded Rubber

While PTFE is the ideal seal material for the e-axle, molded plastic is the perfect solution for valve housing. The valve housing needs a seal that will withstand high temperatures and pressure in the area. The T-junction area of the seal is the most problematic area known for failure. 

Molded rubber seals are push-in-place rubber gaskets that perform well under pulsating pressure. These gaskets can handle temperatures of up to 302°F (150°C) and 50 Bar pressure. In addition, it requires more gland space than seals used in a traditional combustion engine.

Conclusion

Electric vehicles are rising in popularity. However, due to the nature of their engines, they require different seals than a traditional combustion engine. These seals need to have lower friction and handle high-speed rotation.

Need seals for your electric vehicle manufacturing? Contact us today to find out how we can create custom seals for your project.

by Bill Vardeman Bill Vardeman No Comments

Understanding FEP Encapsulated Helical Springs

 

FEP encapsulated helical spring seals are approved for cryogenic and FDA use.

Fluorinated ethylene propylene (FEP) is one of the most popular jackets for encapsulated rings used in cryogenic, corrosive environments, and even FDA-approved food grades. It is well-known by many of the trade names Teflon FEP, Neoflon FEP, and Dyneon FEP. FEP encapsulated helical springs are one type of these seals.

Let’s take a closer look at what an FEP encapsulated helical spring is, the properties of these seals, and the benefits of using them.

What is an FEP Encapsulated Helical Spring

FEP Helical spring seals are created from helical springs. These are elastic coiled mechanical devices. Most consumers are used to seeing helical springs in equipment and devices that store and release energy.

A helical spring seal provides sealing solutions for industries operating in extreme conditions. These seals provide a gas-tight sealing system that meets environmental regulations and reduce fugitive emissions.

FEP encapsulated helical springs seals are housed within a durable, chemical jacket made from fluorinated ethylene propylene. The FEP jacket allows the spring seal to work in chemically corrosive environments or extreme temperatures. 

What are the Properties of FEP Encapsulated Springs

FEP encapsulated helical spring seals’ properties make them ideal for use in extreme conditions. A wide variety of industries can use these spring seals to meet their needs. 

Property Test Method Units Results
Encapsulation Max Service Temperature 8,000-hour aging tests °C / °F 204 / 400
Encapsulation Tear Strength ASTM D1004 (Initial) N / Kg 2.65 / 0.270
Encapsulation Tensile Strength ASTM D638
@ 24°C / 75°F		 PSI / Bar / MPa 3,400 / 234 / 23.0
Encapsulation Impact Strength ASTM D256
@ 24°C / 75°F		 J/m2 No Break
Encapsulation Hardness ASTM D2240 Shore 56
Encapsulation Specific Gravity ASTM D792 g/cm3 2.15
Encapsulation % Elongation @ Break ASTM D638
@ 24 °C / 75°F		 % 325
Encapsulation Flex Modulus ASTM D790 PSI / Bar / MPa 85,000/5,860 / 586
Encapsulation folding Endurance ASTM D 2176 Cycles 100,000
Encapsulation Ignition Temperature Vul045 °C / °F ≥530 / ≥986
Encapsulation Color Visual N/A Off Clear
Moisture Absorption Vul046a % <0.01

 

Advantages of FEP Encapsulated Spring Seals

FEP encapsulated spring seals have many advantages for industrial settings such as cryogenics, aerospace, and oil. It has some of the same advantages as using PFA encapsulated seals.

FEP encapsulated helical spring seals’ properties make them ideal for use in extreme conditions. A wide variety of industries can use these spring seals to meet their needs. 

The FEP jacket protects from corrosive chemicals. FEP has an excellent resistance rating for several chemicals, including the following.

  • Gasoline
  • Hydrochloric Acid (1-5, 20, and 30%)
  • Isobutyl Alcohol
  • Isopropyl Alcohol
  • Propane Gas
  • Sulfuric Acid ( 1-6, 20, 60, and 98%)
  • Sulfuric Hydroxide (1 and 50%)

FEP also has a wide operating range. It works in a temperature range of -420°F (-251°C) to 400°F (204°C). At cryogenic temperatures, FEP encapsulated helical springs remain flexible. This flexibility makes it preferable to O-rings in a cryogenic environment. 

The FEP encapsulated helical springs have low friction. It gives them a minimal stick-slip behavior. A low compression set allows the seal to return to its original shape after deformation.

Best FEP Encapsulated Helical Springs

FEP encapsulated helical seals have several advantages in cryogenic and corrosive environments. They withstand temperatures as low as -251°C (-420°F) and are flexible even at low temperatures. 

Advanced-EMC will work with you to find the encapsulated helical spring solution your application needs, from FDA-approved solutions for use with food processing equipment or a reliable, cryogenically compatible solution for a rocket. Contact us today to learn more.

FAQ

Is FEP silicone?

No, FEP stands for fluorinated ethylene propylene. A Teflon coating protects the seal from hazardous conditions such as extreme temperatures and chemical environments. FEP can encase silicone rings, but it is not silicone itself.

Is FEP the same as PTFE?

No, while both are Teflon substances, there are several key differences. FEP is better with gas and vapor permeability, while PTFE has a lower coefficient of friction. 

 

by Jackie Johnson Jackie Johnson No Comments

Guide to Cryogenic Seals for Marine Loading Arms

cryogenic seals for marine loading arms

A marine loading arm is a flexible, mechanical arm that assists with loading or unloading ships. Typically, they transport petroleum and other chemicals between vessels and containers at the docks. 

Marine loading arms are an alternative to using direct hookups. Like direct connections, you must completely drain the loading arms before breaking off the links by either using high-pressure air to blow out traces or stripping the line using a pump.

Due to what these loading arms carry, they can operate at cryogenic temperatures. Choosing the appropriate seals for this use is essential to ensure the safety of operators and machines alike. Let’s look further into cryogenic seals for marine loading arms.

Why Use Cryogenic Temperatures

Some liquids are too volatile to transport naturally. That is why they are cryogenically cooled into their liquid form. Cooling the air to cryogenic temperatures requires a process of compression, cooling, and expansion.

Moving cryogenic liquids instead of gas is safer and less likely to explode or cause a fire in the event of an accident. However, as these liquids are at sub-zero temperatures, you should use protective equipment when handling them.

There are many types of gasses transported using cryogenic temperatures. The most common use of marine loading arms to load onto ships include liquified petroleum gas, liquified natural gas, liquid oxygen, liquid nitrogen, liquid hydrogen, and liquid helium. The table below shows at what temperatures these gasses are transported.

 

Gas Temperature °C Temperature °F
Liquified Petroleum Gas -48°C -54.4°F
Natural Gas -162°C -259.6°F
Liquid Oxygen -182°C -295.6
Liquid Nitrogen -196°C -320.8°F
Liquid Hydrogen -253°C -423.4°F
Liquid Helium -269°C -452.2°F

 

Cryogenic Seal For Marine Loading Arms Design Consideration

The most common cryogenic loading arm seals are a polymer material that has a metallic energizer. These materials include

  • PTFE
  • PCTFE
  • TFM
  • UHMW PE

PTFE is often the first choice because it is compatible with a wide range of chemicals, has an extremely low coefficient of friction, and is thermally stable. Another valuable material for cryogenic seals is Torlon® Polyamide-imide. Torlon PAI is rigid even at cryogenic temperatures. 

These materials have excellent chemical compatibility, low friction, dry-running, and good dimensional stability. Dimensional changes can be accounted for using a spring-energized seal or sizing the seal by accounting for plastic’s coefficient of thermal expansion. 

Cryogenic seals made with PTFE, and its variants, offer a high strength-to-weight ratio, excellent durability, and self-lubricating properties.

What Cryogenic Seals Materials to Avoid

Traditional compression seals are not a viable choice for cryogenic use. Natural rubber, silicone, Buna-N, fluorocarbon, and ethylene-propylene can handle sub-zero temperatures. However, they cannot correctly seal at cryogenic temperatures. Temperatures below -32°C (-25.6°F) cause the rubber to become brittle.

If you use an inappropriate seal, it will eventually fail. Upon failure, the hazardous liquids flowing through the marine loading arm will escape and can be life-threatening. Some dangers include explosion, fire, asphyxiation, or frostbite.

In addition, there will be dimensional changes between when the seal is installed and when it experiences cryogenic operating conditions. You must ensure that the chosen polymer or elastomer doesn’t become brittle at the cryogenic temperatures involved.

Cryogenic Seal Maintenance Considerations

Periodically, cryogenic seals will require maintenance and replacement. Some things to ensure a longer seal life include understanding conditions, knowing what the seal can withstand, and knowing what to look for when it comes to wearing and lubricating.

Understand Conditions 

The conditions in which your marine loading arm works will affect the seals. Temperature, movement, and pressure will eventually cause the seal to wear out and increase leak rates.  If you know and understand the exact conditions where the seals will work, you can pick the suitable material for longer-lasting usage.

Knowing What the Seal Can Withstand

All seals have a limit to what they can withstand. Cryogenic seals can withstand temperatures from -269°C (452.2°F) to 148°C (300°F). They can typically withstand chemicals, natural gas, petroleum, and liquid nitrogen. They can also withstand high-pressure conditions.

Know What to Look for When it Comes to Wear

All seals wear out. Eventually, cryogenic seals are not excluded. Seals begin to wear on the seal face, causing a leak. You should inspect seals regularly for signs of distress, such as chips and grooves. If there are any indications of wear, then you should replace the seal immediately.

Lubricate

The cryogenic fluids themselves usually make for poor lubricators.  Any added lubricants or even moisture can freeze onto the face of the seal, causing the seal to shatter or, worse yet, the system to lock up and experience catastrophic damage.  However, not using lubrication can result in issues like slip-stick vibration.  

Lubricating cryogenic seals is virtually impossible. As a result, using unfilled polymer materials or a modified material may be the only option.

Best Cryogenic Seals for Marine Loading Arms

Choosing the best cryogenic seals for marine loading arms will depend on what you are transporting. Most cryogenic seals will work in marine loading arms, but some materials work better than others. The most common materials are PTFE, PCTFE, TFM, and UHMW PE.

Advanced EMC offers a wide array of cryogenic seals. If you are interested in purchasing cryogenic seals, contact us today!

 

FAQ

How do you seal liquid nitrogen?

Sealing liquid nitrogen requires either silicone or PTFE seals. If the seal comes into contact with the liquid nitrogen, PTFE seals are the better choice as this material can handle cold flow without causing creep.

What is the purpose of marine loading arms?

Marine loading arms load or unload vessels carrying petroleum products. They are made of several sections of pipes connected by quick-connect fittings and swivel joints. Cryogenic seals are used between the fittings and joints when transporting liquid nitrogen, liquid petroleum, or any other liquid stored at cryogenic temperatures.