PTFE Tube – Properties and Characteristics

The Steel Industry along with the Chemical Processing Industry has been using the fluoropolymer tubing pipes and products made from materials like PTFE and hoses for transferring some of the most highly caustic or corrosive chemicals. The popularity of PTFE tubes is now sky-high and it is gradually replacing carbon and other metal piping that has a low shelf life.

The Chief Properties of PTFE Tube

 PTFE Tubing has some distinctive properties that set it apart from other tubings. There are three factors which determine the properties of PTFE tubes, that is their different sizes, how it is processed and its’ end-applications.

Dimensional stability

The outer and inner diameters of the PTFE tubes are significant. In most cases, the tube is used in an assembly, where fittings have been so designed so that it accommodates the tube.

However, small variations in dimension are usually allowed, but it must be kept in mind that the tube needs to cater to the fitments used with it. 

Burst Pressure

In applications, which involves high pressures, it is imperative that the tube does not capitulate at the time of the service.

There are two critical parameters here that define the burst pressure.

The first one is the tensile strength.  A tensile strength of 28-31Mpa on PTFE tubes, meaning that the value of 25Mpa can pass muster. An under-processed tube can often have a tensile strength of less than 20Mpa.

The other factor that determines the burst pressure is the difference in the wall thickness. The non-concentric tube shows a higher wall thickness on one side as compared to the other side.

 The burst pressure of such tubes is inferior to the good quality tubes, even though the ID and OD may be the same. This issue results in problems galore, especially when you try to braid the PTFE Tube using stainless steel. The problem that you may face in such a situation is, the unevenness in the wall thickness causes one side of the tube to collapse at the time of the braiding due to the immense pressure applied by the stainless steel.

The lesson from this? Try to make the concentricity exceed 95%.

Calculating the concentricity of PTFE is quite simple. If you calculate the ratio of the minimum wall thickness to the maximum wall thickness of the PTFE Tube, you will get the concentricity. So, take for example a 6mm x 4mm tube, which has a wall thickness of 1mm, will require a tolerance of +/-0.025 to achieve such a degree of concentricity.

Visual

Good quality PTFE tube will have properties such as smooth even surface without any signs of pitting or discoloration. Visually, the concentricity is also an important feature. As concentricity influences the extrusion process. Similarly, there are other factors such as quantity of extrusion aid, extrusion speed, and pressure, sintering temperatures and finish on the die, together determine as to how the tube appears. The outward visual factors such as pitting, waviness, and discolouration give clues about the fundamental properties, for example, the tensile strength, elongation, and dielectric strength. 

The above-mentioned characteristics are some of the basic aspects of PTFE tubing that a PTFE tube manufacturer should maintain while making quality tubes.

PTFE: History and Common Applications

PTFE is now one of the most common and popular kinds of industrial coating. The reason being it has innumerable common applications. However, we are not asking to take our word for it, learn more about PTFE, its applications, history, and development of PTFE. 

History of PTFE Hose and PTFE Pipes

Polytetrafluoroethylene, or PTFE, as it is more commonly used, was first created by first created by Dr. Roy Plunkett. 

Like all great discoveries, Dr. Plunkett came across the matter while he was experimenting with some other testing materials which were supposed to be refrigerants.

Interestingly, he was examining a frozen and compressed tetrafluoroethylene when he stumbled on this versatile material. This material had polymerized and had turned into a wax-like solid material. Thus the new material was named “Polytetrafluoroethylene.”

While he was making this discovery, Dr. Plunkett at that was working for DuPont and immediately after they started turning this brand new material into blocks.

The blocks were then turned into varied shapes. Manufacturers all over the world today swear by the use of this product and use it to create different kinds of products. They use it mainly for coating in varied industrial capacities.

 Common Applications of PTFE

  PTFE is not restricted to a single use but can be used in a number of ways. The common applications of PTFE in some of the industries that utilize this material are the following,

·         Pharmaceuticals – PTFE coatings are indispensable to the pharmaceutical industry because they provide over braid seals and strength which helps clean the system.  If the pharmaceutical industry has set impossibly high standards for all materials used within it, PTFE, fortunately, lives up to these tall standards.

·         Cryogenic – The cryogenic industry cannot do without the PTFE either, chiefly because it can withstand extremely high temperatures and on the other hand can also withstand extremely low temperatures. The material is perfectly suited for piston rings, hydraulic hoses, fuel lines, or liquid air systems.

·         Automotive – In the automotive industry the air brake systems require over-braided hoses and for that PTFE caters to these requirements really well.

When the material is required to be used on the outside edge of air compressors PTFE can fill in, as it can withstand extremely high temperatures.

 Also, since PTFE can remove deposits of carbon particles, it becomes an integral part of all types of automotive applications.

 

·         Aerospace industry – PTFE is also an integral part of the aerospace industry as it is part of different components like fuel hoses, tubing hoses, and hydraulic hoses. 

PTFE is often braided with Kevlar for additional protection.

 Also, PTFE is mostly used for applications that require the tempering of heat in components like oil, fuel, water, and alcohol. In the aerospace industries, it is the pneumatic and hydraulic systems, which use PTFE.

·         Chemical industry – In the chemical industry there are some highly reactive chemicals which react with most materials, for transfer of such chemicals you’ll find that mostly PTFE is used for product interchange. Refrigeration systems and steam lines also contain PTFE. It is a competent substitute for materials like corrugated, stainless steel hoses and so on.

PTFEtubes and PTFEhoses are generally regarded as a versatile product, one that can be used in most industries, reason enough for you to get acquainted with this product and use it for different purposes.

PTFE Hose and Hose Fittings

Modern gasoline affects modern day pipes. While changing the gasoline can be problematic changing your pipes makes a lot of sense.  Just swapping the conventional rubber fuel hoses with PTFE pipes can solve your problem.

What is PTFE? It is the abbreviation for Poly Tetra Fluoro Ethylene, but it is better known as its common trade name Teflon.

Earlier PTFE hose was chiefly used mostly for brake- and hydraulic fluid transfer applications. What’s brought a big change in PTFE fuel hoses is that they are now available with a "conductive core" inside. 

There is a carbon lining which is added at the time of manufacturing and it provides a path for any static charge in the line.

 When a non-conductive fluid like diesel, gasoline, methanol, ethanol, or similar fluid passes through the pipe at high velocities, stray electrons, are generated. 

Now, when such is not a very favorable case when it comes to gasoline that is why the conductive core of the PTFE fuel hose slashes down the chance of the static charge generated by the stray electrons.

Features of PTFE Hose and Hose Fittings

If you are wondering since PTFE hoses are more expensive than conventional rubber fuel hoses whether they are worth their steep price.

It certainly is as it lasts for a long time whereas rubber hoses need to be changed from time to time.

• ·         PTFE hose is too stiff for hose clamps. It does not fit to create a good seal, so it needs unique aluminum fittings for securing it.
  
  
  ·         PTFE is slightly stiffer than your average rubber hose material, although it has a much smaller outside diameter. That means the new hose is able to adjust to the bend requirements of most applications.
  
  
  ·         When it is combined with metal braid, PTFE pipes can withstand any type of conditions can even withstand high pressures and non-stop flexing and vibration. Braided PTFE hoses can endure hundreds of flex cycles without buckling under with fatigue or failure.
         
  .       Hoses made of PTFE can withstand as high temperatures as -100°F to+500°F (-73°C to +260°C) under  most operating conditions.  
  
  
  ·         Since no substance can adhere to PTFE as its property can maintain the purity of any fluid which is transferred into this type of hose. It can be safely used for different fluids, as it has a coefficient of friction as low as 0.05, it prevents build-up and maintains high flow rates.
  
  
  ·         PTFE is moisture resistant. It is an FDA approved material for food contact.
  
  
  ·         One of the problems of PTFE fittings and hose has been non-swivel designs, which makes "clocking" the fittings very difficult.  A semi-swivel AN-fitting design is a great way of solving the problem.
  
  
  The PTFE Hose Fittings are manufactured high-quality raw materials. They are based on several parameters to ensure that they last a long time. PTFE hose and hose fittings are widely known for their dimensional accuracy, excellent strength and can be easily installed. Because PTFE hose and PTFE hose pipe are durable and last for a real long time, these fittings are widely acclaimed in the market.