3PE coating system is a multilayer coating composed of three functional components: a high performance fusion bonded epoxy (FBE), followed by a copolymer adhesive and an outer layer of Medium Density Polyethylene (MDPE) or High Density Polyethylene (HDPE), which provides protection against external corrosion.
An anti-corrosion layer is crucial to the life of buried pipelines. Some pipes of the same material are buried in the ground for decades without corrosion, and some leak in several years. It is because they use different outer coatings.
3PE anti-corrosion generally consists of 3 layers of structure:
First layer of epoxy powder (FBE> 100μm)
Second layer of adhesive (AD) 170～250μm
The third layer of polyethylene (PE) 2.5～3.7mm
In the actual operation, the three materials are mixed into a whole, and after processing, it is firmly combined with the steel pipe to form an excellent anti-corrosive layer. Its processing methods are generally divided into two types: winding type and round mold coating type.
Almost all kind of steel pipes could do epoxy coating, such as
Stainless steel pipe
ASTM A312, ASTM A269 stainless pipe
Carbon steel pipe
API 5L line pipe from Grade B to Grade 80
ASTM A53 pipe (Hot dipped galvanized steel pipe)
ASTM A106 pipe
ASTM A252 pipe
ASTM A134 and A135
ASTM A333
Alloy steel pipe
ASTM A335
Nickel Alloy pipes
CRA clad or lined pipe
| Outer diameter of steel pipe(mm) | Length of steel pipe(mm) | Type of anti-corrosion | Processing capacity(m2/h) |
| External: φ426mm～φ1620mm | 8,000mm～18,000mm | 3PE/FBE(external+internal) | ＞400m2/h |
| Internal: φ711mm～φ1620mm |
Polyethylene is not fragile under low temperature, there for, it is safe used in the temperature at the range of -60℃~60℃. So it can adapt to going down of pipeline, Work in winter. Due to good impact performances, PE pipeline won’t easily to break.
Experiments shows that PE pipe wear resistance is 4 times of pipe. especially in area of transporting mud. Compared to varnished pipe, PE coated pipe have better wear resistance. 3PE have smooth surface, its manning coefficient is 0.009. Because of smooth internal surface and non-sticking performance, 3PE coated steel pipe shows higher ability for transporting, and reduce the loss of pressure and water transporting. Low water permeation characteristic provides improved isolation from sea water compared to the other coating systems and FBE pipe.
3PE coated steel pipelines in manufacturing process won’t add heavy metal stabilizer, the PE material have no poison and harm, is a kind of green material, and itself can recycled will not cause pollution to the environment.
3PE coating steel pipe mainly use hot melt and fused connection, keep the interface and pipeline connect as a whole. There is no water and gas leakage.
3PE’s weight only account 1/8 for steel pipe, easily to move, bend, welding process is convenient and fast, lower fees for whole project, obvious economic benefits.
