PTFE-lined pipe

PTFE-lined pipe is a type of specialized piping equipment designed for conveying highly corrosive media.It is mainly used in industries such as chemical,pharmaceutical,metallurgy,and power generation,and is resistant to corrosion from chemical media such as nitric acid,sulfuric acid,hydrofluoric acid,and aqua regia.With a steel structure lined with PTFE(Teflon),produced through composite technology combining metal pipes and fluoroplastics,these pipes combine mechanical strength with corrosion resistance,earning PTFE the reputation of the“King of Plastics.”

Manufacturing Types

Molded Type:Produced by molding PTFE powder,suitable for high-pressure and high-temperature applications(–196℃to+250℃)under harsh working conditions.

Extruded Liner Type:Made by inserting extruded PTFE sleeves into steel pipes.More cost-effective,suitable for less demanding medium environments.

The product can withstand working pressures up to 2.5 MPa.For sizes DN≤250 mm,it can endure negative pressure down to–90 kPa.All products undergo hydrostatic testing at 1.5 times design pressure and spark testing to ensure tightness.The PTFE lining features non-stick and high-lubrication properties,reducing medium residue and energy loss,and performs stably in high-temperature(long-term use≤150℃)and high-vacuum conditions such as distillation systems.

Properties of PTFE Material

Resistance to atmospheric aging:Excellent weathering,irradiation resistance,and low permeability;properties remain unchanged after long-term exposure.

Non-flammability:Oxygen index below 90.

Acid and alkali resistance:Insoluble in strong acids,strong alkalis,and organic solvents.

Oxidation resistance:Resistant to corrosion from strong oxidizing agents.

Working Characteristics of Steel-PTFE Composite Pipes

Temperature resistance:Operating range–100℃to+250℃.

Pressure resistance:Positive pressure up to 2.5 MPa;withstands negative pressure of 70 kPa at room temperature.

Corrosion resistance:

Steel-PTFE composite pipes can resist nearly all chemical media(including concentrated nitric acid and aqua regia),except molten alkali metals(Li,K,Na),chlorine trifluoride,oxygen difluoride at high temperatures,and high-velocity liquid fluorine.They can operate continuously at 230℃–250℃.

Steel-PVDF or other fluoropolymer composite pipes show excellent resistance to halogens,halogenated hydrocarbons,strong oxidizers,boiling acids/alkalis,and many organic solvents.However,they are not resistant to fuming sulfuric acid,concentrated hot sulfuric or nitric acid,ketones,esters,and amines above 90℃,or high-temperature sulfonating agents.

Advantages of PTFE Material

High-temperature resistance–usable at working temperatures up to 250℃.

Low-temperature resistance–retains mechanical toughness;elongation remains at 5%even at–196℃.

Corrosion resistance–chemically inert against most chemicals and solvents;withstands strong acids,strong alkalis,water,and various organic solvents.

Weather resistance–best aging resistance among plastics.

High lubricity–lowest coefficient of friction among solid materials.

Non-stick–lowest surface tension of any solid material;does not adhere to substances.

Non-toxic–physiologically inert and harmless to organisms.