The Advantages of PTFE in Demanding Filtration Applications

In today’s highly competitive world there are companies that are moving into higher value-added chemicals and materials. Further, environmental regulations are increasing the stringent rules as governments at the national, state and local levels are requiring that industries control pollution by limiting emissions. Thus there is a quest to limit those wastes and emissions. In this competitive environment, the filter end user, filtration design engineer or filter end user will require material to increase the performance and durability. This shows that the polytetrafluoroethylene  PTFEtube is well suited to cater to the multitude of these demands and help the industry to meet the many environmental obligations.

PTFE OVERVIEW

PTFE was discovered by Dr. Roy Plunkett at DuPont in 1938. Earlier it was limited to wartime applications until after World War II when it was first introduced under with the trademark Teflon. Today, there are a number of suppliers which offers 60,000 tons/year. Where the large fluorine atoms form a sheath around the carbon backbone, providing it from attack from organic, acid, or base solvent, except at elevated temperatures. This sheath also imparts low surface energy and providing a very low coefficient of friction (< 0.1) and nonstick properties. This low surface energy renders PTFE hose both hydrophobic and oleophobic, so neither the aqueous nor oily materials adhere to it. Thus, it is really easy to mechanically remove any dust or filter cake which gathers on the surface. 

PTFE monofilament or thread is fit for filter manufacture either as:

Talking about a sewing thread specific for sewing filter bags of PTFE or made for high-performance fibers that are used in hot gas filtration, such as baghouse filters found in the stacks of coal-fired boilers, cement plants and so on. 

As a woven scrim for needle punching PTFE or other high-performance fibers to form the fabrics that are utilized in baghouse or other filter formats.

A filament for wound-core filters is used for corrosive liquid filtration applications.

All of these applications tap onto the superior chemical resistance and offers an excellent heat resistance of PTFE.

Is PTFE is Moldable

PTFE tubing provides a perfect blend of commercially available and high performance tubing. PTFE tubing typically means flexible tubing with wall thickness from 0.5 to 2 mm. PTFE tubing with wall thickness more than 2 mm is rigid and is called a PTFE tube or PTFE pipe. Generally PTFE tubing appears to be milky white to translucent however PTFE tubing can also be manufactured in many colours. PTFE tubing with high transparency is desirable in many applications as the visibility of the fluid flowing through the PTFE tubing is a key factor. It is also possible to manufacture PTFE tubing having electrical conductive properties or having enhanced resistance to abrasion.

ptfe tubing

PTFE tubing are usually connected to machines, equipment or supply lines using metal or connectors manufactured using other Materials like PEEK and PVDF.  So that the connections are leak free it is important that the PTFE tubing are manufactured with tight tolerances. Advanced Fluro Tubes manufactures PTFE tubing with dimension  tolerances  as low as 50 microns. Dimension tolerance for PTFE tubing depends on the ID and OD of the PTFE tubing. There are many secondary operations that can be done on PTFE tubing like flanging, flaring, cutting, spiral cuts, braiding etc. When braided the pressure rating increases many folds and bend radius decreases. PTFE tubing can be braided using stainless steel, polyester and aramid fabric to suit the application. PTFE tubing has a density of 2.15 – 2.18. PTFE tubing density is very important as it tells us about the performance we can expect of this PTFE tubing.

Dielectric strength of PTFE tubing is 18 to 24 kv/mm. This parameter is important for electrical applications. This parameters basically tells us how much voltage will be insulated by PTFE tubing before it breaks down as an insulator. The higher the value to better. A value less than above mentioned range could indicate a issue in the manufacturing process or use of PTFE raw material not suited for high voltage electrical applications.Percentage elongation at break of PTFE tubing varies from 200 to 400%.

PTFE tubing should have a smooth Internal diameter as they are used to transfer highly viscous fluids. When the ID of the tube is not smooth the viscous fluid tends to “stick” to the tube wall and eventually clogs the tube. Smooth ID is also important to food grade application. Smooth interval diameter of PTFE tubing prevents bacterial buildup. PTFE tubing in smoothbore form is flexible however as the dimensions increase the flexibility decreases. Often when used in tight spaces PTFE tubing cannot bend as per available space. To solve this problem PTFE tubing is convoluted. Convolutions ensures the bend radius is reduced and PTFE tubing can be bent and fitted in small spaces.

PTFE tubing has a milky white to translucent appearance. There are application where visibility of the fluid is important to spot contamination for example or to check for deposition on PTFE tubing ID. For such applications increased transparency is required. Advanced Fluro Tubes can manufacture PTFE tubing with increased transparency.There are instances where an industry has specifications for colors of tubing that can be used for specific applications. Advanced Fluro Tubes manufactures PTFE tubing in many colors like red, blue, yellow, green, orange and black.

Antibacterial application require that the ID and OD of the PTFE tubing is very smooth and shiny. This ensures there is no entrapment of fluid and material reducing deposition of material. Material deposited on rough surfaces is difficult to clean using insitu steam cleaning. This eventually causes bacteria build up. The deposited material also reduces the flow and adversely affects the performance of the system.

PTFE tubing is generally supplied as coils however can also be supplied as cut pieces or cut lengths.Some applications demand that PTFE tubing be rigid while others requires more flexibility.  PTFE tubing are manufactured in continuous lengths upto 400 mtrs. It is therefore important to test for leakages via pin holes not visible to naked eyes.

What is the Difference Between Hoses and Tubes - PTFE Products in India

The majority of industries like the steel Industry and chemical processing industry have been consistently utilizing pipes made of fluoropolymers and is made of materials like PTFE and PTFE hose for many years for carrying highly reactive or corrosive chemicals. The popularity of these pipes is on the rise because of its properties and it is fast replacing the pipes made of carbon and other metals.

The Properties of PTFE Tubes 

The PTFE tube properties are different from another kind of pipes and it is its unique properties which set it apart from carbon and the metal pipes.

Thermal properties- PTFE tubing can withstand temperatures up to 680 °F for a short duration under cryogenic conditions; PTFE tubes does not change even at high temperatures like 500 degrees Fahrenheit and can withstand cold temperatures down to -320 °F.

Electrical properties- PTFE tubing has great electrical properties as it is a great insulator and a great surface resistivity.

UV resistance and wearability - PTFE tubing has excellent UV resistance and wearability.

Wear and Friction Qualities- PTFE tubing has a relatively slippery and smooth surface, so it also has a great wear and frictional qualities.

PTFE is commonly used as a non-stick coating for pans and different types of modern items of cookware. PTFE can also be used in containers and pipes for handling various types of reactive and corrosive chemicals; this is mainly due to its non-reactive properties. Another way of applying PTFE is using it as a lubricant. If you use it this way, PTFE can drastically reduce the friction within machinery reduces the “wear and tear,” and greatly improves energy consumption.

PFA or PTFE hose is regarded as much superior to PTFE tubes on the basis of flexibility, particularly when it comes to tubing applications. On the other hand, PTFE hose’s capacity to bear life or repetitive folding also called flex life is lower than that of PTFE. PTFE pipes have a far more potent resistant power to heat than PTFE Hose.

PTFE Hose is far more affected by the absorption of water and weathering but is far superior to PTFE when it comes to the property of salt spray resistance. The most notable quality of PTFE tubings over PFA is perhaps its electrical properties. It has the dielectric constant of PTFE and a very similar dissipation factor, yet PFA has a dielectric strength which boasts of the property of having three to four times higher than that of PTFE.

Design and Fabrication of PTFE Tubes

PTFE is Poly Tetra Fluoro Ethylene a polymer that was discovered by Mr.Plunkett at Dupont.

PTFE exists in powdered form and do not melt and flow. When heated to temperatures above 350-degree Celsius PTFE it transforms from solid to the gas phase. Because PTFE does not melt flow it is not possible to injection mold it. PTFE tube can, however, be changed into a molded, ram extruded or paste extruded. PTFE Tubing is manufactured with the help of paste extrusion. It is flexible. It is possible to manufacture PTFE tubing which is as small as 0.3 mm to max 100 mm and wall thickness as small as 0.1 mm to 2 mm. PTFE tubing service temperature varies from -60 to + 260-degree Celsius.

PTFE tubing is popular because of its flexibility because it offers chemical resistance in commercially available polymers and also because of its non-stick quality (in fact it is one of the most slippery substances known.

 Some standard metric sizes of PTFE tubes are as follows  2×4, 4×6, 6×8 & 8×10 while some of the standard metric sizes are as follows 1/16×1/8, 1/8×3/16, 3/16×1/4, 1/4×5/16, 3/8×1/2″.

Small sizes of PTFE tubing are used for Chromatography, spectrometer & Titrators while larges sizes are utilized for sampling lines, pneumatic supply and as electrical, heat or chemical insulation. The pressure rating of PTFE tubing depends a lot on the IDxOD of the tubing.

PTFE tubing is fitted to equipment and machines that use compression fittings such as connector and adapters. It is important that the dimension of ID & OD of the PTFE tubing be very tight so there is no leakage at the end fitting. The fittings are manufactured in various materials such as stainless steel grades SS304 or SS316 and also using PTFE material. PTFE fitting is used in conjunction with PTFE tubing in applications where metal fittings are not allowed. 

 It’s important to note that leakages happen because of incorrect cutting of the PTFE tubing before it is inserted in the fitting by PTFE tubing manufacturers. One needs special cutters for a straight cut.

PTFE tubing is manufactured in continuous lengths, which ranges from 25-250 meters or more depending on the IDxOD of the PTFE tubing. PTFE tubing is also a part of coils or wound on plastic or wooden spools.

PTFE tubing has a milky opaque or milky translucent appearance and this appearance depends on the type of PTFE raw material that is used for the manufacturing use. PTFE tubing can also be manufactured in varied colors such as red, black, blue, green, yellow. In addition, PTFE tubing comes with a color stripe for identification.

PTFE tubing is flexible and you can easily bend it.  Care should be taken however to ensure the bend radius is not in any way less than the bend radius kept separately for the IDxOD of the PTFE tubing.

Why is PTFE Tube Regarded as a Versatile Pipe? Chief PTFE Properties

Polytetrafluoroethylene or more commonly known as PTFE is a synthetic fluoropolymer made up of of tetrafluoroethylene.  

It is hydrophobic, high density, non-wetting, and is of high temperatures, PTFE tube is what you can call a versatile material as it is used for a number of applications, though it is more popular for its non-stick properties.

 

 The Chief Properties of PTFE

The teflon hose is a flexible, thermal resistant, chemical resistant, non-stick and also electrically resistant material with its melting point being around 327°C, and pure PTFE has high flexural strength, even in very low temperatures, high dielectric strength, and electrical strength. Potentially high resistance to water and fairly low coefficient of friction. PTFE’s density ranges from the 2200 kg/m3 mark.

The only con is that it may have a reaction to chemical agents and solvents such as chlorine trifluoride, xenon difluoride, cobalt (III) fluoride, or elementary fluorine if put through under high pressure and temperature conditions. PTFE also does not have a good resistance to high energy radiation, which forces the breakdown of PTFE molecules.

A Few Modified Features of PTFE

Apart from PTFE there are other two copolymers which has different properties.

PFA or Perfluoroalkoxy is similar to PTFE because of its properties as it is flexible, very chemically resistant also thermally stable and can be used up to 260 degrees C even if PTFE has the properties of being able to creep, PFA is creep resistant and is used for a number of properties such as extrusion, melt-processing, injection moulding, transfer moulding, compression moulding and blow moulding.

TFM, better known as PTFE-TFM, is polytetrafluoroethylene with perfluoropropylvinylether taken as an additional modifier, boasting of a material which is stiff being creep-resistant like PFA, and weldable.

Advantages of PTFE

There is no doubt about the fact that PTFE is indeed very versatile and has a huge number of applications to speak of. 

It is an integral part of manufacturing and engineering industries, it is not limited to using in tubes or liners or for handling or storing corrosive chemicals, but it is also used in parts such as bearings or screws to increase the lifespan of the parts and also the machinery it is part of.

The longer lasting, higher-performance parts ensure that it enhances the efficiency of any machine it is part of, thus reducing the requirement of constantly replacing parts, which leads to saving money and reducing waste. Hence it will cut down on constant maintenance issues with the equipment which will lead to the reduction of any expensive manufacturing downtime due to the repairs and faults.

PTFE coat is a type of material that is non-wetting, and enables self-cleaning which helps reduce the cost of frequent cleaning.

 Teflon textile finishes are environment-friendly because the finish repels water and oil stains, and reduce the requirement of dry-cleaning and fabrics will also tend to dry up quickly, using far less energy with methods as tumble drying, and with the reduction of wear, it also tends to last longer.

White PTFE Tubing Features and Applications

The Steel Industry and chemical processing are largely indebted to the PTFE tubes consistently utilize fluoropolymer pipes that are made up of myriad metals such as Teflon or PTFE tubes and hoses. These are so adapted that can carry corrosive chemicals or highly reactive chemicals. PTFE pipes are more useful than pipes made of carbon and other metals.

Polytetrafluoroethylene (PTFE) is a high molecular polymer and is a large part of the cable and tubing industry as it has some tremendous properties right from electrical properties to chemical inertness also high-temperature resistance. This material caters to the needs of the manufacturing and industrial sectors because it has specific properties. 

 The Properties of PTFE Tubes

The properties of PTFE tubings are largely different from metal pipes or carbon pipes.

Thermal properties- PTFE has heat-resistant properties and this enables this kind of pipes to withstand high temperatures of 680 °F for a certain period of time under cryogenic conditions; PTFE tubes do not change their properties even when they undergo extreme high temperatures such as 500 degrees Fahrenheit and it is  cold temperatures almost down to -320 °F.

UV resistance and wearability- PTFE tubes have other qualities such as UV resistance and wearability quality.

Wear and Friction – PTFE has its smooth surface and it has excellent wear and frictional qualities.

Electrical properties- PTFE tubing also has insulation properties, in other words, it is a great insulator and it’s and surface resistivity is pretty great.

A pure PTFE character is white. The material is used for numerous applications and is corrosion-resistant, and is suitable for a clean, sanitary, temperature and another bad environment. Black PTFE PTFE can improve or change performance enhancers, such as carbon fiber, graphite, carbon, molybdenum disulfide, para-phenylene and so on. 

These enhancers can help enhance wear-resistant, creep resistance of PTFE, high temperature, rigid and electrically conductive. Also, when it is filled with glass fibers, ceramic powder white material, the composite material still is white ( or ceramic color, white rice ). Such materials are highly suitable for use and can be used for wear resistance, creep resistance, the high temperature working under a bad environment to work, although it is not suitable for the food-grade industries.

  

As PTFE tube manufacturers of pretty sound repute, they ensure that they carry out proper quality checks and ensure that they carry out extremely tight tolerances which besides preventing leakage also reduces scrap.

As a leading PTFE tube supplier, the manufacturers ensure that they deliver pipes and tubes right on schedule making their customers satisfied and happy. 

Some applications properties increase the abrasion resistance of self-lubricating PTFE tubes. Here engineers emphasize the application and serve customized solutions that application requirements.

For example, there are numerous applications that require PTFE tubes with antistatic properties.

Besides, virgin PTFE tubes Advanced fluoro tubes also manufacture numerous services for example such as end flaring, sleeving, specific cut lengths and so on.