Tube in PVDF SDR21 5000 mm natural

A tube in PVDF is used where ordinary plastic tubes are not enough against the medium, but where metal becomes too expensive or too sensitive to corrosion. The material belongs to the fluoropolymers, holds long-term temperatures up to 150 degrees and has a V0 flammability rating per UL 94. Water absorption is negligible, around 0.04 percent, which keeps the dimension stable even in a damp environment.

PVDF has a chemical resistance that covers large parts of what the process industry needs. Concentrated and diluted acids, halogens, chlorine gas, chlorinated water, aliphatic and aromatic hydrocarbons, alcohols and most solvents cause no problems. Hot strong bases, polar aprotic solvents and certain amines are on the borderline, however, and should be evaluated against a resistance table before installation. For potable water, fluoropolymers in this class are a well known choice.

As a tube material PVDF is machinable, weldable and bondable with the right pretreatment. Hot plate welding and extended hot air welding work very well if the welding parameters are kept and the material is properly dry. Bonding requires a primer or flame activation, since the low surface energy otherwise prevents adhesion. Mechanical machining, cutting, chamfering, threading, goes quickly and cleanly.

In the process industry, PVDF tubes are typically used for acid lines in surface treatment and pickling plants, chlorinated water and sodium hypochlorite in water and wastewater treatment plants, bromide and fluoride media in semiconductor production, and high purity liquids in chemical synthesis and laboratory environments. The tubes also suit the transport of beverages and food in high purity systems where an FDA approved material grade is used.

Mechanically, PVDF is stiffer and holds its shape better than PTFE and keeps the dimension under pressure better than PP or PE-HD at elevated temperature. That means the pressure rating holds some way up into the heat where cheaper thermoplastic tubes lose load capacity. For operation close to the material's temperature ceiling, a proper safety margin and a check against the manufacturer's data sheet for the current pressure temperature curve are always recommended.

The natural color is bone white to slightly opaque. Lengths and wall thicknesses come in a standard range, cut to order. Remember that PVDF has lower impact strength at low temperatures; below zero degrees the range of use shrinks somewhat and the material becomes more sensitive to knocks. In outdoor installation it takes UV well but can chalk on the surface over a long time.

Better to ask than to guess: send the medium, temperature, operating pressure and dimension and we will give a recommendation on whether PVDF is enough or whether another fluoropolymer is the safer choice.

The five meter tube in the SDR21 version has a thicker wall and therefore a higher pressure rating, for lines that have to stand up to higher pressure.