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Advanced Properties and Applications of PTFE in Sealing Technology

PTFE has a unique combination of properties that make it ideal for use in sealing technology. One of its most notable characteristics is its ability to withstand extremely high and low temperatures. PTFE can operate in temperatures ranging from as low as -200°C to as high as 260°C, making it an excellent choice for applications where sealing performance needs to be maintained at extreme temperatures.

PTFE

Another significant advantage of PTFE is its chemical resistance. It is highly resistant to various chemicals, including acids, alkalis, and organic solvents. This makes it an excellent choice for use in chemical processing plants or other facilities where exposure to harsh chemicals is common.

PTFE also has excellent non-stick properties, which make it ideal for use in applications where adhesion could compromise the effectiveness of the seal. Its low coefficient of friction means that even under heavy loads or with repeated cycles of movement, PTFE will not experience significant wear or degradation.

In addition to these properties, it has outstanding electrical insulation characteristics and acts as a barrier against moisture and dust.

Manufacturing PFE Gaskets

Pure PTFE gaskets are produced by molding directly from suspended material or cutting (turning) from PTFE sheets (rods). Molding plates have uneven density and poor flexibility while turning plates have a relatively uniform density. Still, their material is curved due to the influence of the processing technology, which is not conducive to installation and use.

Modified PTFE gaskets add a certain proportion of functional materials, such as glass fiber or graphite powder, during production. The resulting gasket provides improved strength and durability compared with pure PTFE gaskets while maintaining this advanced material’s desirable properties.

Despite its many advantages, however, some limitations are associated with using PTFE in sealing applications. For example:

  • It can be difficult to achieve consistent compression when using pure PTFE gaskets due to their poor flexibility
  • PTFE can be prone to creep under sustained pressure, which can result in a loss of sealing performance over time
  • PTFE is unsuitable for high-pressure applications as it has low tensile strength and may deform or fail under high loads.

Applications for PTFE 

Despite these limitations, PTFE remains one of the most advanced materials available in sealing technology. Its unique combination of properties makes it ideal for use in various applications where reliable sealing is essential.

One potential application area where PTFE could increase use is the automotive industry. As electric vehicles become more prevalent, there will be an increased demand for seals that withstand harsh operating conditions. Its excellent temperature resistance, chemical resistance, and non-stick properties make it an ideal choice for use in battery enclosures and other critical components.

Another potential application area is within the food processing industry. Many food products are highly acidic or alkaline, which can cause traditional seals to degrade over time. PTFE’s chemical resistance makes it an excellent choice for acidic or alkaline foods. At the same time, its non-stick properties mean that any residue left on the seal after cleaning can easily be removed.

In conclusion, Polytetrafluoroethylene (PTFE) has many advanced properties that make it ideal for use in sealing technology. Its ability to withstand extreme temperatures while maintaining effective sealing performance sets it apart from other materials commonly used in this field. While some limitations are associated with using the material in certain applications, such as those involving high-pressure loads, its unique combination of properties means it remains one of the most important materials currently available. Over time, we may see even greater advances made with this remarkable material with continued research and development into new formulations and manufacturing techniques.

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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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Exploring the Benefits of Fluorolon PTFE in Industrial and Engineering Applications


Fluorolon PTFE (Polytetrafluoroethylene) is a unique synthetic polymer with many benefits for industrial and engineering applications. This versatile material can be used for a wide range of purposes, from chemical processing to cookware. In this article, we will explore some of the key benefits and uses of Fluorolon PTFE.

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

Chemical Resistance


One major benefit of using Fluorolon PTFE is its excellent chemical resistance properties. This material is highly resistant to acids, bases, solvents, and other corrosive substances. This makes it an ideal choice for use in applications such as chemical processing plants or food processing industries where harsh chemicals are often used. It can also be used as a protective coating on metal surfaces to protect them from corrosion or damage from exposure to corrosive materials.

High-Temperature Resistance


Another benefit associated with Fluorolon PTFE is its high-temperature resistance properties. This material can withstand temperatures up to 260°C (500°F) without losing its strength or shape – making it an excellent choice for use in insulation, gaskets, seals, and other high-temperature applications such as aerospace parts or engine components that require superior heat resistance capabilities. The thermal stability offered by this polymer also ensures that parts maintain their original dimensions even under extreme conditions making them ideal for precise manufacturing processes where dimensional accuracy is critical.

Low Friction Properties


Fluorolon PTFE also offers exceptionally low friction properties, making it suitable for use in various mechanical components such as bearings and slides where minimal friction between moving surfaces is desired. Its low coefficient of friction helps reduce wear on machinery parts resulting in increased operational life spans while simultaneously providing smoother operation with less vibration compared with traditional materials like steel or bronze alloys. Furthermore, since no lubricants are required, energy consumption costs due to frequent maintenance procedures associated with lubrication are significantly reduced compared to traditional metals.

Non-Stick Properties


In addition, Fluorolon PTFE has impressive non-stick properties, making it ideal for use in cookware, baking sheets, conveyor belts, and other industrial equipment. Its non-stick characteristics enable food products like cakes, cookies, etc., to slide easily off surfaces resulting in efficient production processes while maintaining product quality standards at the same time. Furthermore, these non-stick characteristics help reduce clean-up times after the production process, thereby saving both time & money.

Electrical Insulation Properties

Last but not least, one important benefit this polymer provides includes its electrical insulation capabilities making it perfect for use within high-voltage industrial equipment & electronic components alike. Its ability to prevent electricity from leaking out allows companies within the electronics industry to create safer products without having to worry about hazardous shocks occurring during usage, thus ensuring customer safety at all times, leading to higher customer satisfaction & loyalty levels over time.

At Advanced EMC Technologies we use Flourolon Virging PTFE primarily for seals, seats, bearings, and insulaotrs. All our Flourolon PTFE is FDA and dairy approved. We offfer both Virgin PTFE ASTM-D4894 and filled PTFE ASTM D4745-06.

PropertySpecifiedUnitsMethod
Specified Gravity (FEP) Only2.14 –2.19gr/ccASTM D792
Maximum Recommended  Stretch2 %N/AASTM D638
ES Seals Are For Type ServiceStatic N/A–
Coefficient of Friction (FEP)0.19StaticASTM D3702
Dielectric Constant (FEP)N/AN/AASTM D150
Dielectric Strength (FEP)N/AN/AASTM D257
Thermal Expansion No Spring8.3 x 10^5thin/in/°FASTM D696
Compressive StrengthN/AN/AASTM D695-57
FEP Seal Temperature Range-420 to 428°F–
PFA Seal Temperature Range-420 to 500°F–

To summarize, the many benefits associated with using Fluorolan PTE should not be overlooked, especially when considering various industrial & engineering-related applications that call out these specific attributes offered by this synthetic polymer beyond any other commonly available alternatives currently present in the market today. Its ability to resist chemicals and withstand higher temperatures than most polymers without losing shape/strength, alongside offering superior low friction/non-stick qualities coupled with excellent electrical insulation capabilities, clearly demonstrates why so many industries opt to choose Fluorolon PTFE over any other material available.

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The Effect Surface Finish Has on PTFE Seals

Surface finish plays an essential role in the effectiveness of PTFE seals. The different finishes provide different degrees of contact between the two components, which affects the seal’s strength and reliability. In this paper, we will discuss the effect of surface finish on PTFE seal performance and suggest ways to improve seal quality.

Surface finish on PTFE

The Influences of Surface Finish on Friction

The surface finish is critical for polymer-based seals. Despite being considered a soft plastic, PTFE is significantly harder than traditional o-ring materials. Because of this, if the mating surface is designed for other materials, it can cause the PTFE seals to leak.

As you can see in the graph below, the improvement in the surface finish has a favorable effect on the frictional force required.

The following specifications were used in the force test that resulted in the above data.

  • Stroke Speed: 4 in/min (102 mm/min)
  • Shaft Diameter: 0.1875in. (4.762mm)
  • Ambient Temperature: 73°F (23°C)
  • Mating Surface Material: 17 -4 PH S.S.
  • Mating Surface Hardness: -40 Rc

Surface Finish Influences on Wear

The finish of the mating surface is one of the main factors in the PTFE seal wear. Wear on the seal is generally proportional to frictional force. In other words, less friction reduces the wear on the seal. 

The following graph shows how a smoother surface finish reduces the PTFE seal wear rate.

To calculate the wear rate in microinches RMS, we used the formula IN3 -MIN/LB-FT-HR -10-9. For microinches Ra, we used the formula CM3 -MIN/KG-M-HR -10-9.

We used the following test parameters during our testing to ensure accuracy for each test.

  • Surface Speed: 55 fpm (17 m/min)
  • Loading Stress: 55 lb./in2 (4 bar)
  • Wear Rate in Air: @ PV 3025 lb./in2 x ft/min (7.5 N/mm x m/min)
  • Mating Surface Hardness: Rc 42
  • Matin Surface Maerial 17 -4 PH Stainless steal
  • Mating Surface Finish: 1.6 to 111.1 microinches RMS (1.4 to 100 microinches RA)
  • Ambient Temperature: 70°F (21°C)
  • Ambient Relative Humidity 75% RH
  • Duration 5 Hours
  • Seal material FP

Influences on Sealing Ability

Finally, we looked at how the surface finish affected PTFE’s sealing ability. In general, the sealing ability of PTFE is proportional to the fluid’s viscosity. If a media, like gas, has a reduced viscosity, it is more difficult to seal. In these situations, having a smoother finish on the mating surface can help ensure fewer leaks.

We’ve found that different mediums require not only different finish ranges between them but also different finish ranges when considering if the surface is dynamic or static. You can see our suggested finish in the table below.

MediaDynamic Surface Static Surface 
Gases and Liquids at Cryogenic Temperatures2 to 4 microinches RMS
(1.8 to 3.6 Microinches Ra)		4 to 8 Microinches RMS
(3.6 to 7.2 Microinches Ra)
Gas at Non-Cryogenic Temperatures6 to 12 Microinches RMS
(5.4 to 10.8 Microinches Ra)		12 to 32 Microinches RMS
(10.8 to 28.8 Microinches Ra)
Liquids8 to 16 Microinches RMS
(7.2 to 14.4 Microinches Ra)		16 to 32 Microinches RMS
(14.4 to 28.8 Microinches Ra)

As you can see, the mating surface finishes can profoundly affect PTFE seals. Because of this, if the mating surface is designed for other materials, it can cause the PTFE seals to leak. Finally, we examined how this affected PTFE’s sealing ability. In general, the sealing ability of PTFE is proportional to the fluid’s viscosity. 

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CNC Machining Basics

cnc machining

Computer Numerical Control (CNC) machining is a manufacturing process that uses pre-programmed computer software to dictate the movement of the tools and machines. It allows devices such as lathes, mills, and grinders to cut three-dimensional objects.

To understand CNC machining, we are going through a basic overview of CNC machining, including terminology, how they work, and the advantages and limitations of a CNC machine.

Terminology

Understanding the terminology associated with CNC machining is the first step to understanding CNC machining. CNC stands for computer numerical control. A computer and CAM software are used to animate, control, and observe the motions of the machine using digital data. 

CAM stands for computer-aided machine or manufacturing. It uses different software programs to generate tool paths and NC code for a CNC-operated machine based on data from 3D computer models. CAM only uses CAD to generate code for the device to follow. 

CNC machines could be robots, sheet metal stamping machines, lasers, grinders, lathes, water jet cutters, or welders. The computer controlling these machines is often an onboard controller. However,  the controller may also be an external PC.

How Do CNC Machines Work

CNC machines cut a desired piece based on what is programmed into the system. Therefore, it begins with designing the component. This step is necessary to establish the dimensions and features of the finished product.

Often the component design takes place in a CAD-CAM package. It allows the flow to continue through the program without going through file translation. Suppose they are not in the same package or software package. Then the CAD models will have to be imported into the CAM software.

Designing the component using CAD software allows you to construct the real piece and see what it looks like on the screen. The program is a code generator for the CNC machine that compiles coordinates to direct the cutting head during the manufacturing process. 

The final step in CNC machining is to choose the proper parameters. These include:

  • Voltage
  • Cutting speed
  • RPMS

The software will choose how the parts are arranged and oriented in relation to the raw materials. The part shape and tooling influence the configuration of the other parameters and equipment used.

Open and Closed Loop CNC Machining

CNC machining takes place in either an open-loop or closed-loop system. Open and closed-loop refer to the control process of the system. The position of the piece is determined by the type of system used.

The signal runs in a single direction between the CNC and the motor in an open-loop system. This system uses stepper motors, but the use of stepper motors doesn’t necessarily indicate an open system.  This system is commonly used when the forces and speeds are minimal.

In an open system, once the motor is in place, the controller has no feedback. That means unless a limit switch is tripped, the controller runs the operation as if there are no errors. 

A closed-loop system allows the controller to receive feedback. Because the controller can receive feedback, the controller can rectify irregularities and correct errors when necessary. There are two types of closed-loop systems. With the first type, the return signal feeds directly into the controller. The other type returns the signal feedback to the PC running the program.

A closed-loop system is necessary to ensure speed and consistency. It is the ideal choice for accuracy in creating a part. However, because there are more working parts, they have more components that can fail and be harder to tune.

CNC Machining Advantages

There are many advantages of using CNC machining for part manufacturing. For one, it is an excellent method for producing multiple parts that are identical to one another. If you need upwards of 100 parts, CNC-machined parts are more cost-effective than 3D printing.

CNC machining creates precision pieces. With a tolerance of +/- 0.127mm, machined parts come down to +/- 0.005mm. The equipment can produce them quickly. 

CNC machines can be used with various materials. Alloys such as zinc and magnesium are standard materials. In addition, aluminum, steel, brass, and titanium are common choices.

Limitations

While CNC machining has many advantages, the process has several limitations. One of them is using older machines to perform this process. CNC machines require a system that can perform demanding tasks. As a result, older computers and devices may not be able to handle the tasks.

Another limitation is that most CNC controllers may be constrained by only comprehending circular arcs and straight-line motions. Archs are often allowed on the main XYZ planes. However, some parts require a five-plane rotation that some controllers can’t comprehend. 

Conclusion

CNC machining is a significant advancement in manufacturing with the aid of computer technology that will give you accurate parts. It is a quicker and more efficient way to produce parts. 

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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.

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Introduction to PTFE Lip Seals

PFTE Lip seals

Radial shaft seals are often found in aggressive environments with high temperatures and pressures. Unfortunately, these environments are also frequently dry-running and unsuitable for traditional radial shaft seals. So, what are the options if traditional radial shaft seals won’t work? Using PTFE lip seals as rotary shaft seals can offer better protection and longer life than conventional radial shaft seals. Understanding these lip seals are essential to helping you make the right choice for your sealing needs.

What Are PTFE Lip Seals

PTFE (polytetrafluoroethylene) lip seals have a lip on the interior diameter (ID) that allows it to fasten to an outer diameter (OD) of a metal casing or shaft. The seal is completed with a gasket sandwiched between the sealing lips.

Not all lip seals are spring-energized. Therefore, the force from radial contact is lower. The lower pressure allows the seal to function at higher surface speeds of up to 10,000 sfpm. This type of seal is for high rates, making it the go-to choice for sealing rotating shafts.

PTFE Lip Seal Fillers

PTFE Lip seals can be enhanced by using fillers instead of virgin PTFE. Fillers can help the seal withstand sintering temperatures. Some of the filled compounds include:

  • Carbon-Graphite
  • Carbon Fiber
  • Aromatic Polyester
  • Molybdenum Disulfide and Fiberglass
  • Fiberglass
  • Graphite
  • Mineral
  • Stainless Steel

Each filler offers higher temperature resistance and lower creep rates than virgin PTFE. In addition, some offer lower abrasion or better corrosive protection depending on the filler type. Which type of filler you want will rely on the application where you use the lip seals. 

Applications That Use PTFE Lip Seals

PTFE lip seals are found in most applications where speed is concerned. However, they also are ideal for conditions where highly corrosive compounds or in dry, abrasive environments. 

Aerospace

The aerospace industry needs seals that can cope with extreme temperatures, surface velocities, and high pressures. External gearbox seals are just one place where PTFE lip seals are used in the aerospace industry.

Lip seals can handle the extremes and offer advanced fuel consumption efficiency. Better efficiency of burning about half-gallon of fuel per mile can save airlines an operating cost of $1.7 million per year. 

Other instances in which the aerospace industry uses lip seals include military applications such as:

  • Lift fans for vertical lift
  • Wing flap and slats actuator seals
  • Rotorhead
  • Equipment in arresting system to catch aircraft as it lands on aircraft carrier decks

Automotive

In the automotive industry, PTFE lip seals are employed in the drive shafts of the top-fuel blowers in NASCAR engines. Traditional crankshaft seals were burning out in these engines due to the high speeds and rapid pressure increases within five minutes at racing speeds.

They are also in e-drive and cooling systems in electric vehicles. Lip seals in electric cars can handle the shaft speeds seen in these automobiles. Electric vehicles can run at over 18,000 RPM, a higher rate than gas-powered cars. 

Conclusion

PTFE lip seals are ideal for rotary shafts operating at high speeds and temperatures, such as in the automotive or aerospace industries. Choosing suitable fillers can also help extend the seal’s life. Contact us today, and we can help you determine which PTFE lip seal options you want.

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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.

 

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Molded PTFE Billets: An Overview

Molded PTFE Billet

Teflon (PTFE) billets are compression molded tubes and rods made of Polytetrafluorethylene used in numerous industrial applications covering almost every industry, including chemical processing, automotive, food, aerospace,  medical device, semiconductor, and fluid handling. These functional parts are popular due to Teflon’s chemical resistance, extreme temperatures, low friction properties, and ability to mold them into the precise shape and size needed.

Types of Molded  PTFE Billets

The molded processing techniques we employ are compression, isostatic, and automatic. The determination of which method to use will depend on the type and size of billets being produced, the industry they are being used in, and the manufacturer’s preference.  

Compression

Compression molding for PTFE  billets is one of the three main processes, with isostatic and automatic as the other options (we will discuss these in a later article). To make a billet using this process, one must design and create the source mold for the rod or tube. The compression mold is a two-part mold that includes a preform component.

The performance has the same shape as the tube or rod being processed.  The material is loaded into the mold, pressed under specific pressure and time depending on the grade of PTFE being processed, and then ejected for the mold. 

The pressure causes the material inside the preform to conform to the mold’s shape. As a result, any excess material leaks out of the mold. Once the molding process is complete, the billet is ejected from the mold.

Once the billet is extracted from the mold, it is now in what is called the “Green State,” compact into the desired shape, but no molecular change has occurred; this only happens after sintering in our ovens for a designated time between 650 to 715 degrees F. 

The billet is left to cool at room temperature. Once cooled, excess material can be machined off to make a smooth, perfectly formed Teflon billet. 

Advantages of using compression molding include:

  • Strong parts
  • Lower tooling costs
  • Broad design options
  • Lower waste generation
  • Large part manufacturing

Sintering Molded Tubes, Rods, or Semi-Finished Parts.

Sintering results in a change in the PTFE powder that reorganizes the molecules into a compound. To sinter Teflon billets:

PTFE Powder

 

  • Temperatures must be between 675°F and 700 °F (357°C and 371°C).
  • The oven must have good airflow.

  • Billets must be supported to ensure that they do not sag

Adding an annealing cycle during the sintering processes will help to stop cracks from forming while the compound bakes. Once the billets are out of the oven and cooled to room temperature, they can be machined.

Molding Process

While all molds have physical property variations, the overall process is similar. Therefore, the variations between compression, isostatic, and automatic molded billets are inconsequential to the prevalent use. 

The molding process is two-step. It begins with packing the mold and pressing the powder,  called the “green state.” Next, the mold is placed under specified pressures depending on whether the material is unfilled (Virgin) or filled with various fillers, glass, carbon, graphite, etc. pressure of up to i.

After pressing, the item is removed from the mold. Workers must be careful during the ejecting of the tube or rod. Mishandling of the green material could result in cracks. Once the mold is removed, the billet is sintered.

conclusion

Molded PTFE billets are ideal for many industries. The properties of PTFE make them chemical resistant, have a low coefficient of friction, and can be manufactured compliant with FDA, Class VI Medical, NACE, Aerospace, and Semiconductor  Standards approved for use in medical and food industries. In addition, clean Room Molding for Ultra Pure applications is available.