Pure-Fusion™ Welding & Lining Technology
Edlon - Fluoropolymers
Edlon® provides its Pure-FusionTM welded loose liners in a LowStressTM design in order to overcome the issue of long term environmental stress cracking. This significantly prolongs the lifespan of the liner under high thermal loading and very aggressive environments.
Edlon utilizes a proprietary seaming technique, wherever possible in all our products, called fusion welding. The ability to offer 100% fusion welded seams in many of Edlon’s products is unequaled in the industry.
Pure-FusionTM welds exhibit tensile and elongation properties that match those of virgin fluoropolymer films. Edlon’s fusion welds allow for natural flex and strain, eliminating stress risers and minimizing the chance for stress cracking or other damage.
Advantage of Edlon's Instrument-controlled Pure-Fusion Fluoropolymer Welding
Fabric-backed linings rely on adhesives to bond them to the substrate. This bonding is also essential when employing hot are welding for seams. Those air weld seams have statistically higher fabrication flaws which makes then have properties that are a fraction of those of the virgin material. This can result in a higher permeation rate than the bulk of the lining.
There is also a higher chance of incorporating micro-voids and poor weld penetration depth. The non-uniform cross-section of the air welds means they are inherently more susceptible to stress cracking which can result in a reduction of the lifespan of the lining.
In contrast, Edlon® PureFusion™ welds are machine-made and instrument-controlled to produce reproducible and reliable seam welds, regardless of overall seam lengths and the number of linings fabricated. Fusion welds exhibit tensile and elongation properties that match those of virgin fluoropolymer films. The retention of elongation properties (i.e. elasticity) of the weld is vitally important when the service temperature is high.
PureFusion™ welds allow for natural flex and strain, eliminating stress risers and minimizing the chance for stress cracking. This is critical for service at elevated temperatures.
Edlon not only fusion-welds liner sheets together, but also utilizes this technique to install nozzles into liners. Edlon’s fusion-welded nozzle seams enable us to offer low stress nozzle and manways designs to eliminate some of the most common failure modes. Fusion-welded nozzle seams significantly reduce stress risers and the risk of cracking that is associated with air welds in these critical areas.
Smooth and Crevice-Free Welds
Edlon's proprietary fusion welding technology ensures fast, smooth, high-strength indiscernible seams. PureFusion™ seams are produced in a controlled environment. All Pure-Fusion liners are formed from virgin unpigmented resin and spark tested at 20,000 volts DC.
No step or crevices are created between liner sheets for metal ion contamination, bacterial growth, or other impurities that could collect and affect your process and eventually cause it to fail.
Comparison between conventional air welds and Edlon® Pure-FusionTM
Various conventional air welds and Edlon’s Pure-FusionTM samples were tested as per ASTM D638 specification, using 3mm thick virgin PFA film. Data were compared with the virgin film.
ASTM D638 specification: Show TS/EB data comparison (graphically)
Weld Strength Comparison (% of Virgin) - Per ASTM D638
|Weld Type||Elongation at Break||Tensile Strength|
|V Groove Air Weld and Cap||5-25%||50-65%|
|Machine Fusion Weld||85-100%||90-100%|
Thermoforming of Lining
Edlon creates liners for all vessel heads using a thermoforming technique that allows heads to be formed in one piece, rather than welded from multiple pie-shaped sections. Thermoformed heads eliminate many feet of air welds typical of industry in industry-standard bonded linings and dual laminate vessel heads.