3LPE Coating

The 3LPE coating line for steel pipeline is a whole set of equipment which is the most advanced coating of the buried steel pipeline. This equipment represents the most advanced coating process being popular in the whole world.

By combining the FBE coating technology popular in North America and the PE/PP technology popular in Europe, this production line can coat pipes with single-layer FBE coat, double-layer FBE coat, double-layer PE coat, 3PE coat, 3PP coat and also is capable for coating concrete balancer pipe.

The（3LPE) three coating layers of 3LPE coated pipe are as follows:

Layer 1: Anti-corrosion layer. This layer consists mainly of fusion bonded epoxy resin;

Layer 2: Copolymer adhesive. The function of this layer is mainly to bond the fusion bonded epoxy resin of the first layer and the polyethylene of the third layer;

Layer 3: This layer is mainly composed of polyethylene. This layer is for physical protection.

3LPE Coating Process

1) Inbound Rack and Conveyor

The pipe will be loaded by this unit.  It consisted of inbound rack and convey system. All actions are driven by hydraulic system. The Main rack made of thick wall rectangle structure steel tube is to ensure convey stable and to meet the max heavy-load requirement of heavy pipe. Catch and release pipe is controlled by PLC automatically.

2) Induction Preheating

This unit is to heat up the pipe for better shot blast performance. The induction unit is middle frequency induction heater. The surface of pipe would be 50-60℃.

3) Epoxy Coating 

Special design of corona hi-voltage electrostatic powder spraying gun can meet the requirements of high temperature. Hi-voltage electrostatic generator can provide 100kV（DC） power. This ensures the high speed and high efficiency. Spraying gun made in Japan. Modular design is good for maintenance. Spraying room made of stainless steel, light inside. Powder recycling uses cyclone and cartridge. Material of cartridge is polyester fiber and micro holes aluminum foil composite material. This material can eliminate electrostatic and can be washed by water. 

4) Adhesive and PE coating 

The adhesive will flow out from the hanger die to coat on the epoxy layer. It is could enhance the strength between PE layer and epoxy layer. PE and adhesive layers would be laminated online. 

5) Checking Platform 

Now the pipe is ready for checking. This platform is for quality check and transfer the qualified pipe and unqualified pipe to different zones.