5 Key Factors to Consider When Buying PTFE Hoses
PTFE is a very versatile polymer. It’s a polymer that has very high chemical resistance and high service temperature of 260 deg Celsius.
PTFE is extruded using an extrusion technique called paste extrusion. PTFE can be paste extruded to form pipes and tubes. Tubes extruded from PTFE are milky white in color and semi flexible. The PTFE tubes in natural virgin form are electrically non conductive however it is possible to add a conductive agent to PTFE and extrude PTFE conductive tubes also called anti static tubes. The PTFE tubes can then be braided to manufacture PTFE Hose also known as PTFE Braided Hose.
There are 5 key factors to consider when buying PTFE Hose and they are as follows :
1. The PTFE tube quality.
PTFE tube is the most important component of PTFE hose and the challenging component to manufacture. Many properties of PTFE tubes have to be considered like density, tensile strength & elongation. The density of a good quality PTFE tube should be in the range of 2.15 to 2.18. The elongation of a good quality PTFE tube.
should be more than 250% and the tensile strength should be greater than 250 Kg/cm2, the high the tensile strength the better. PTFE tubes when extruded may develop pin holes during the extrusion process. Manufacturers of good quality PTFE tubes will have a very tight control on the process variables to ensure defect free PTFE tubes. One way to assure that PTFE tubes are pinhole free is to pressure test to ensure there are no pin holes.
The other important factor is the uniformity of the PTFE tube wall thickness. PTFE tube concentricity([Min Wall thk / Max Wall Thk]*100) should be more than 80%. This ensures that the burst pressure or proof pressure is uniform across the length of the PTFE Hose coil length.
2. Burst Pressure
PTFE hose conform to standards like SAE 100 R14 and others. PTFE Hoses are named based on their bore. so a 1/4″ PTFE hose will have a 1/4″ bore. The OD of the hose will vary from manufacturer to manufacturer. Each PTFE hose size has a minimum burst pressure account to various standards. The burst pressure of a 1/4″ PTFE hose is around 700-720. When buying PTFE hoses ensure that the burst pressure and hence the working pressure confirms to a standard applicable to your industry.
3. Bend Radius
PTFE hoses are used in equipment with tight spaces. It’s needs to be bent to connect two ports. The minimum bend radius, in this case, becomes an important factor. The lower the bend radius the better it is. Choose a PTFE hose with a bend radius that confirms to industry standard or that suits your requirement.
4. Braid Material
The most ubiquitous braid material is SS304, and the quality of SS304 wire has a big impact on PTFE hose quality. The SS304 braid cover provides reinforcement to the PTFE tube which ensures the PTFE hose service pressure is high. The diameter of the SS304 braid wire has to be uniform to ensure the service pressure of the resultant PTFE hose assembly is within a narrow range.
5. PTFE Hose Testing
Customers procure PTFE Hose based on a technical data sheet. The question is what % of PTFE hose procured confirms to the specification. PTFE Hoses undergo rigorous testing like proof pressure test, burst pressure test, elongation test and so on.
A quality PTFE hose manufacturer ensures that they test every coil of PTFE hose produced using non-destructive testing methods. Advanced Fluro is a leading brand of PTFE Hoses that meet high standards. We export to many countries around the world. We would be happy to discuss your technical requirements for PTFE hose.
