Fluoropolymer (PTFE) Hose Industrial Applications

Fluoropolymer hoses are widely used in chemical processing, chemical transfer, chemical filling, and compressed gas transfer/filling applications. Hoses are lined with PTFE, FEP or PFA and can be reinforced with a range of materials such as rubber …
All of the Fluoropolymer hoses consist of an extruded PTFE core. PTFE has an excellent flex life,handles high temperatures and offers superior chemical and corrosion resistance. Additionally, PTFE can be extruded with a static dissipative innercore to prevent the attraction of dust and other particulate and reduce the build-up of static charges.
In the case of a PTFE hose, static electricity is caused when a nonconducting fluid flows at a high velocity through the PTFE natural core tube. When a static charge builds up in the tube of a PTFE hose, it will look for the path of least resistance to ground. If the tube is nonconductive,then the path of least resistance may be to pierce through the wall of the PTFE tube to the conductive Stainless Steel Braid and eventually to the metal fittings and back-to ground through the equipment to which the hose assembly is connected.
The purpose of a static dissipating tube on the inside of the hose is to provide an acceptable path of least resistance and allow the static build-up to dissipate through the core tube to the metal fittings and eventually to ground.

FLUOROPOLYMER HOSE CONSTRUCTION

Fluoropolymer hoses
1. Core
Contains Media
Materials: Natural or Static-Dissipative PTFE with a Smoothbore or Convoluted Core


2. Reinforcement
Provides Resistance to Internal Pressure
Materials: Stainless Steel


3. Jacket or Protective Sleeve
Protects Reinforcement
Materials: Silicone, Polyurethane

 

 

FLUOROPOLYMER HOSE FEATURES

  • ƒ Excellent chemical compatibility
  • ƒ Handles extreme temperatures to +450°F
  • ƒ Environmentally safe
  • ƒ Low moisture permeability
  • ƒ Low friction minimizes pressure drops and deposits 

FLUOROPOLYMER HOSE APPLICATIONS/MARKETS

  • ƒ Chemical transfer lines
  • ƒ General hydraulics
  • ƒ Compressed air/gases
  • ƒ Adhesive dispensing
  • ƒ Coolant Lines
  • ƒ Medical Gases 

IMAGES FOR FLUOROPOLYMER HOSE

Fluoropolymer Hose

Extrusion Foaming of PTFE Fluorocarbon Resins

possess melt viscosities low enough for processing in melt extruders. Additionally, FEP and PFA are well suited for extrusion foaming while maintaining their.
Fluorocarbon Extrusion

INTRODUCTION

SukoPTFE has developed patented technology for the compounding and processing of fluoropolymer foam resins. The foam process involves the continuous injection of a gas such as nitrogen directly into an extruder filled with molten resin. A specially designed extruder screw is typically utilized to create the polymer gas mixture with an inert nucleating package contained in the resin to help promote cell growth. Foams of up to 60% voids have been demonstrated through the use of this process.

APPLICATIONS FOR MELT PROCESSABLE PERFLUORINATED RESINS

SukoPTFE Teflon® FEP and PFA perfluorinated resins possess melt viscosities low enough for processing in melt extruders. Additionally, FEP and PFA are well suited for extrusion foaming while maintaining their low dielectric constant and low dissipation factors, both necessary for twisted pair and coaxial cable insulations.
Data cables are used in the transmission of electronic signals in a variety of settings and applications. The key electrical properties required for these cables include a low dielectric constant and a low dissipation factor. These properties can be enhanced by foaming the insulation. Depending on the resin used, cables having a foamed insulation allow cable miniaturization, weight reduction of the end product,and the transmission of clear high-quality electrical signals at high signal speeds.
Foamed cables fabricated from sukoptfe fluoropolymer resins have become extremely popular in computer manufacturing and installation of network systems. Cables made with sukoptfe Teflon® FEP or PFA have low-flame and low-smoke attributes. These cables can be routed through plenums and other air handling ducts, reducing the need for the costly installation of electrical conduit.

STRUCTURE AND PROPERTIES OF FLUOROPOLYMERS

The ability to melt extrude these polymers, combined with such characteristics as low dielectric constant and low flammability made FEP and PFA well suited for wire and cable applications

GENERAL ASPECTS OF FOAMED INSULATION

The dielectric properties of polymeric insulation on wire can be improved by the inclusion of gaseous bubbles. However, this must be done in a way that results in small and evenly distributed voids throughout the insulation. Large bubbles can lead to failures within the insulation and uneven void distribution can cause mismatched performance around a conductor. DuPont has developed technology for the controlled nucleation of nitrogen gas in the fluoropolymer melt as it is extruded and drawn onto wire.
Foaming provides a collection of distinct advantages that are not achievable with conventional melt extrusion techniques. For FEP and PFA, when foaming technology is utilized, the dielectric constant drops as the void content increases. The reduced dielectric constant achieved through foaming increases the relative velocity of propagation while lowering capacitance. Because of these improved attributes over conventional melt extrusion, foaming also allows for reduced wall thickness, leading to a corresponding drop in overall weight of the required insulation.

EQUIPMENT REQUIREMENTS FOR FOAMING

Conventional extruder screws for melt extrusion have two key zones, a feed and a shallow metering zone. In foam extrusion applications, a 3 or 4 stage screw is used with feed, compression, metering, and mixing stages. A reduced diameter ring is machined at the middle of the first mixing section to reduce the pressure in that region, facilitating the gas injection.
Proper sizing of the extruder and appropriate screw design are key factors in the foaming process.
As the polymer is melted and fed through the extruder barrel, pressurized gas is injected at or about sonic velocity by a high pressure pump. Proper sizing of the injector via the metering orifice is required to deliver a controlled gas injection into the polymer at the desired levels.

SAFETY CONSIDERATIONS

The major safety consideration for the extrusion of fluoropolymers and other organic polymers is the removal of off-gases released from hot polymers into work areas. This can be accomplished by the installation of exhaust hoods at the die and the hopper heaters, if utilized. Extruding into water – either a quench tank or a partially filled container – for purging is also recommended.

Types of extrusion

Extrusion is a compressive deformation process in which a block of metal is squeezed through an orifice or die opening in order to obtain a reduction in diameter and increase in length of the metal block. The resultant product will have the desired cross-section. Extrusion involves forming of axisymmetric parts. Dies of circular on non-circular cross-section are used for extrusion. Generally, extrusion involves greater forming forces. Large hydrostatic stress in extrusion helps in the process by enhancing the ductility of the material. Metals like aluminium, which are easily workable, can be extruded at room temperature.
Plastic Extrusion

TYPES OF EXTRUSION:

Direct extrusion:Direct extrusion, also called forward extrusion, is a process in which is the billet moves along the same direction as the ram and punch do. Sliding of billet is against stationary container wall.Friction between the container and billet is high. As a result, greater forces are required. A dummy block of slightly lower diameter than the billet diameter is used in order to prevent oxidation of the billet in hot extrusion. Hollow sections like tubes can be extruded by direct method, by using hollow billet and a mandrel attached to the dummy block. 
Indirect extrusion:Indirect extrusion (backward extrusion) is a process in which punch moves opposite to that of the billet. Here there is no relative motion between container and billet. Hence, there is less friction and hence reduced forces are required for indirect extrusion. For extruding solid pieces, hollow punch is required. In hollow extrusion, the material gets forced through the annular space between the solid punch and the container. The variation of extrusion pressure in indirect extrusion is shown above. As seen, extrusion pressure for indirect extrusion is lower than that for direct extrusion. Many components are manufactured by combining direct and indirect extrusions. Indirect extrusion can not be used for extruding long extrudes.
Hydrostatic extrusion:In hydrostatic extrusion the container is filled with a fluid. Extrusion pressure is transmitted through the fluid to the billet. Friction is eliminated in this process because of there is no contact between billet and container wall. Brittle materials can be extruded by this process. Highly brittle materials can be extruded into a pressure chamber. Greater reductions are possible by this method. Pressure involved in the process may be as high as 1700 MPa. Pressure is limited by the strength of the container, punch and die materials. Vegetable oils such as castor oil are used. Normally this process is carried out at room temperature. A couple of disadvantages of the process are: leakage of pressurized oil and uncontrolled speed of extrusion at exit, due to release of stored energy by the oil. This may result in shock in the machinery. This problem is overcome by making the punch come into contact with the billet and reducing the quantity of oil through less clearance between billet and container. 
Impact extrusion: Hollow sections such as cups, toothpaste containers are made by impact extrusion. It is a variation of indirect extrusion. The punch is made to strike the slug at high speed by impact load. Tubes of small wall thickness can be produced. Usually metals like copper, aluminium, lead are impact extruded. 
Tube extrusion:Employing hollow billet and a mandrel at the end of the ram, hollow sections such as tubes can be extruded to closer tolerences. The mandrel extends upto the entrance of the die. Clearance between the mandrel and die wall decides the wall thickness of the tube. The mandrel is made to travel alongwith the ram in order to make concentric tubes by extrusion.

Direct extrusion

Extrusion is a compressive deformation process in which a block of metal is squeezed through an orifice or die opening in order to obtain a reduction in diameter and increase in length of the metal block. The resultant product will have the desired cross-section. Extrusion involves forming of axisymmetric parts. Dies of circular on non-circular cross-section are used for extrusion. Generally, extrusion involves greater forming forces. Large hydrostatic stress in extrusion helps in the process by enhancing the ductility of the material. Metals like aluminium, which are easily workable, can be extruded at room temperature. Other difficult to work metals are usually hot extruded or warm extruded. Both circular and non circular parts can be obtained by extrusion. Channels, angles, rods, window frames, door frames, tubes, aluminium fins are some of the extruded parts.

Direct extrusion

Direct extrusion:

Direct extrusion, also called forward extrusion, is a process in which is the billet moves along the same direction as the ram and punch do. Sliding of billet is against stationary container wall.Friction between the container and billet is high. As a result, greater forces are required. A dummy block of slightly lower diameter than the billet diameter is used in order to prevent oxidation of the billet in hot extrusion. Hollow sections like tubes can be extruded by direct method, by using hollow billet and a mandrel attached to the dummy block.

Extrusion force, which is the force required for extrusion, in direct extrusion, varies with ram travel as shown in figure above. Initially the billet gets compressed to the size of container, before getting extruded. Also, initially static friction exists between billet and container. As a result the extrusion pressure or force increases steeply as shown. Once the billet starts getting extruded, it length inside the container is reduced. Friction between billet and container now starts reducing. Therefore, extrusion pressure reduces. The highest pressure at which extrusion starts is called breakthrough pressure. At the end of the extrusion, the small amount of material left in the container gets pulled into the die, making the billet hollow at centre. This is called pipe. Beyond pipe formation, the extrusion pressure rapidly increases, as the small size billet present offers higher resistance. As the length of the billet is increased, the corresponding extrusion pressure is also higher because of friction between container and billet. Therefore, billet lengths beyond 5 times the diameter are not preferred in direct extrusion.

Direct extrusion can be employed for extruding solid circular or non-circular sections, hollow sections such as tubes or cups.

The intricate process of plastic extrusion and what it makes

Plastic extrusion is one of the most popular practices in industries nowadays. When it comes to branding, there is a need to get access to a custom manufacturer. These plastic manufacturers will create amazingly designed plastics of all kinds. The goal is to make sure that their clients are able to take their businesses to a whole new level. Take for instance a company like Coca Cola- you will be able to know their plastic bottles even without their label. They are designed in a specific way that people have grown accustomed to and thus associate the bottles with the brand.
plastic extrusion
The process of plastic extrusion
Basically the process of plastic extrusion is a rough one involving lots of heat and pressure. The final product may not tell of the process but it really does matter. It is the amount of heat, pressure and design that determine just how excellent the final product will be. Industrially, plastic resins are converted into millions of finished products within a very short period of time. In as much as the process might sound really complicated, technology has made it easy for people to get it done very fast.
The process begins with the melting of plastic resin. This is where the high temperatures and pressure come in. The plastics are fed into the extruder whose temperature gradually increases from one end to the other. The heat has to be regulated carefully to ensure that it does not go beyond or fall below the required temperature. If it does not reach the optimum temperature then there is going to be a problem getting the plastic melted down. On the other hand if the temperatures are just too high, the chemical composition of the plastic might change which will compromise the integrity of the final product.
As such a team of engineers are involved in the process of plastic extrusion. Their work will revolve around the maintenance of the machinery and seeing to it that the machines run smoothly producing the right quality of product that is desired. Once the plastic has been is melted, it is then poured into a mold which gives it the desired shape. Molding designers are responsible for the work of coming up with the best mold design that works for the clients.
What does this process make?
The process of plastic extrusion can create just about anything. If you are looking to purchase plastic products that will attract your prospective clients while at the same time promoting your brand then you should get in touch with the best custom manufacturer near you. He/she will do everything from the designing to the creation of the final product. They will present you with a variety of designs that you will have to select from. As stated earlier, technology has made it possible for people to come up with fantastic options very fast.
The process of extrusion can be used to make just about anything from the coolest of bottles and pipes to wire insulation and so much more. The only difference is that there are various methods of plastic extrusion that are used to achieve these ends. Therefore, if the manufacturer wants to create a toy, they will do some alterations to the process (simple ones) if they were creating plastic pipes the previous time.
The strength of the final product will depend on the chemistry of the raw material that was used. As you probably know by now, there are just so many types of plastics out there in the market. Each of them brings with it its own pros and cons.

plastic extrusion and custom molding

Plastic extrusion has become quite a popular activity in industries and even technical schools are offering courses to enable individuals to get into this career. One of the fastest growing careers in the world is plastic and rubber mould designing. Custom molding is one activity that all brands seem to desire. They want plastic bottles for their sodas in this form or the other. Brands want to sell the most stylish yet functional water bottles. There are others that want to set up the finest quality plastic and rubber pipes for industrial and even residential purposes. These are just some of the reasons why the career is continually growing in popularity.

What is extrusion?

So people are talking about this process over and ever but in all honesty very few know exactly what it is. Well, generally plastic extrusion is a process whereby plastic melted down and turned into a continuous form. This process is mainly used n the production of items such as pipes, tubing, wire insulation, railing, fencing and so much more. In other words the applicability of extrusion is so high and hence its popularity all over the world. At the most basic level the process involves heating and molding to produce a particular shape.

The process involves use of plastic resin. These are small plastic beads that are fed into the heated barrel of the extruder. The resin is pushed through the barrel by a rotating screw where a temperature of between 392 and 527 degrees Fahrenheit melts the resin. This temperature depends mainly on the polymer that has been used in the creation of the resin. In order to reduce the likelihood of overheating the resin, the heat is increased gradually from one side of the barrel towards the other one.
There is a screen at the front of the barrel which is used to filter out contaminants that might be present in the molten resin. Once the resin has passed through the screen it is sent through a die of particular shape. This gives the product its profile. The profile can be made continuously at whatever length the manufacturer fancies. The final stage is usually the cooling. This is done by use of a water bath. Normally plastic holds heat quite well and therefore cooling can take quite some time to complete. The water bath is usually sealed there is a vacuum that is employed to prevent the product from losing the shape as it cools.

Common types of extrusion

There are various types of plastic extrusion which produce various products. They include:

1. Blow film extrusion

This one is used in the making of things such as plastic shopping bags. The die in this case is normally an upright cylinder where the melted resin is poured.

2. Sheet extrusion

It is also called film extrusion and it is mainly employed in the making of plastic films and sheets. Instead of cooling by water bath, the sheets are cooled by being pulled through a series of about three pinch rollers. The rollers also determine the thickness of the final product in question.

3. Tubing extrusion

This method makes products like medical tubing and straws. The process is rather similar to the basic extrusion but at the die stage a pin is placed inside the die. The melted resin is then pushed into the die and it forms around the pin known as a mandrel.

Die Extrusion – Polymer Extrusion Process

Once a polymer has been melted, mixed and pressurised in an extruder, it is pumped through an extrusion die for continuous forming (after cooling and solidification) into a final product. The most common die types are flat, annular and proŽle. Products made by extrusion include pipe, tubing, coating of wire, plastic bottles, plastic films and sheets, plastic bags, coating for paper and foil, Ž bres, Ž laments, yarns, tapes and a wide array of proŽfiles.
Die Extrusion
Polymer extrusion through dies has certain similarities to the hot extrusion of metals.However, there are also signi-ficant differences. In metal extrusion the material is pushed forward by a ram, while in polymer extrusion the material is continuously supplied by a rotating screw. In hot metal extrusion the temperatures range from 340°C for magnesium to 1325°C for steel, and the corresponding pressures range from 35 to over 700 MPa.1 5 In polymer extrusion the temperatures seldom exceed 350°C, and pressures usually do not go much above 50 MPa at the screw tip. Solid phase extrusion of polymers has been developed for the production of certain high strength products.At low temperatures, the molecular orientation imparted by the forcing of the material through the shaping die remains in the extrudate. Solid state polymer extrusion has certain similaritiesto the cold extrusion of metals.
Blown film extrusion is the most important process for the production of thin plastic Žfilms from polyethylenes.The molten polymer is extruded through an annular die (normally of spiral mandrel construction) to form a thin walled tube which is simultaneously axially drawn and radially expanded. In most cases the blown film bubble is formed vertically upwards. The maximum bubble diameteris usually 1.2 – 4 times larger than the die diameter. The hot melt is cooled by annular streams of high speed air from external air rings, and occasionally also from internal air distributors. The solidiŽ ed Žfilm passes through a frame which pinches the top of the bubble and is taken up by rollers. Coextruded Žfilms with 3 – 8 layers (sometimes up to 11) are also produced by this process, for use in food packaging.
Cast Žfilm and sheet extrusion involves extruding a poly- mer through a  at die with a wide opening (up to 10 m), onto a chilled steel roller or rollers which quench and solidify the molten material. Film is generally defined as a product thinner than 0.25 mm, while sheet is thicker than this.The cast Žfilm process is used for very tight tolerances of thinŽ film, or for low viscosity resins. Most flat dies are of T slot or coathanger designs, which contain a manifold to spread the flowing polymer across the width of the die, followed downstream by alternating narrow and open slits to create the desired flow distribution and pressure drop. Most cast film lines manufactured today are coextrusion lines, com- bining layers from as many as seven extruders into the product through multimanifold dies, or single manifold dies with the aid of feedblocks. 
In Žfilm extrusion, the shear rates at the die lips are usually ~103 s21. When the wall shear stress exceeds a certain value (usually 0.14 MPa in research papers, higher in industry with the help of additives),the extrudate surface loses its gloss owing to the sharkskin melt fracture phenomenon.Sharkskin can be described as a sequence of ridges visible to the naked eye, perpendicular to the flow direction.
Pipe and tubing extrusion involves pumping a molten polymer throughanannulardie,followingwhich the extruded product, while being pulled, passes through a vacuum sizer where it attains its final dimensions. This is followed by spray or immersion cooling and cutting to fixed lengths. Pipe of diameter up to 2 m or greater is made by this process, and tubing with diameters from 10 mm down to below 1 mm. The annular dies are normally of spider or spiral mandrel design.
In wire and cable coating processes, individual wires or wire assemblies are pulled at very high speed through a crosshead die, at right angles to the extruder axis. In high pressure extrusion, the polymer melt meets the wire or cable before the die exit, for example insulating of individual wires. In low pressure extrusion, the melt meets the cable after the die exit, for example jacketing of assemblies of insulated cables. Very high shear rates are frequently encountered in this process(up to 106 s2 1 ) and low viscosity resins are used.
ProŽfile extrusion is a manufacturing process used for products of constant cross-section. These can range from simple shapes to very complex profiles with multiple chambers and Žfingers. Examplesrange from picture frame mouldings, to automotive trim, to edging for tabletops,to window lineals. The extruded materials are classiŽ ed (roughly) as rigid or fiexible. The typical proŽle extrusion line consists of an extruder pumping a polymer through a proŽle die, followed by a sizing tank or calibrator, additional cooling troughs, a puller and a cutoff device. The design of profile dies requires considerable experience and patience.Output limitations in profile extrusion are encountered owing to either sharkskin (for thin products produced from high viscosity polymers) or the ability to cool thick walled products. Polymer pipe and proŽfile extrusion is similar to the hot extrusion of metals for the production of continuous hollow shapes of barlike objects. However, the mathematicalmodelling of these processesfor metals is based mainly on elastic – plastic flow hypotheses.
In melt spinning, the molten polymer  ows through numerous capillaries in a spinneret (up to 1000). The poly- mer is delivered under pressure by a gear pump for accurate metering, after passing through a Ž lter which follows the extruder. On exiting the capillaries, the Ž laments are attenuated to the desired diameter.For the production of very thin Žfibres, the melt blowing process is used. In this process the Ž bres are attenuated by the drag force exerted by a high velocity air jet.