Spiral Wrap 3LPE Coating Line DN219-1420 mm

 

The anti-corrosion coating processing line includes:
-steel pipe transmission system
-Internal and external shot blasting system
-dust collection system
-pipe heating system
-electrostatic spraying system
-PE coating system
-water cooling system
-end cutting system
-hydraulic and pneumatic system
-testing system
-electronic control system

Pipe is blasted to Sa 2.5 or better, purged internally and end-masked. An induction coil brings the surface to the coating window, and the sequence then runs continuously: electrostatic epoxy powder application, copolymer adhesive extruded through its own head and pressed onto the rotating pipe, then polyethylene from the side extruder through a 1000 mm T-die, laid as a spiral with a controlled overlap. The pipe turns on an independent rotating drive whose speed is locked to conveyor travel so the pitch stays constant regardless of diameter. Water spray cooling follows, then joint cutting, end bevelling and a full circumference holiday scan. Where a plant runs several diameters the recipe change is a die and seal change with stored settings, generally inside 30 minutes if the tooling is pre-staged.

1. Pipe diameter: DN219-1420 mm (8 to 56 inch)
2. Processing capacity: ≥250m²/h
3. Cleaning level: ≥Sa2.5
4. Materials for production: epoxy powder, adhesive, polyethylene

Standards Compliance

ISO 21809-1 is the usual international reference for three-layer polyethylene, with DIN 30670 in Europe and GB/T 23257 in China; Russian and Central Asian projects are supplied against GOST requirements. Blasting and surface preparation are carried out to ISO 8501-1. Where the contract names an owner specification, we list the clauses we meet and any we do not, in writing, before the order, rather than implying general conformity.

Applications

Oil and gas transmission pipe; large water conveyance mains; city gas high-pressure headers; thermal and industrial process pipe; large diameter structural tube. This is also the configuration used when a plant needs to produce both three-layer and two-layer coated pipe from one line, because the epoxy and adhesive stages can be bypassed while the wrapping section continues to run. Buyers specifying this line are usually coating to a contract standard where impact resistance and disbondment test results are inspected by a third party, so the wrap pitch consistency matters commercially and not only cosmetically.

Service & Support

Turnkey delivery covers workshop layout, foundation design, manufacture, shipping, installation supervision, commissioning, trial production and operator training. Two to three engineers are on site for 15 to 30 days, and the schedule is planned so that commissioning finishes before your first commercial order. Documentation is in English, covering layout, foundation, electrical schematics, PID and manuals. Spares ship by air within 72 hours of a confirmed order. Warranty: 12 months machine, 24 months drive train, and a two-year package of wear parts on request.

Why Choose Qingdao Huashida

The wrapping line is the configuration we have delivered most often into projects where the buyer already operates a coating plant and knows exactly what to inspect on arrival. Our three-layer polyethylene line carries a Shandong Province First-Set Technical Equipment award, and we hold 58 invention patents and 38 software copyrights. A coating service company in the United Arab Emirates has bought additional three-layer capacity from us in three separate years; a plant in the Moscow region took delivery of a 1,620 mm line and later added further capacity. Repeat orders in this business mean the wrap pitch and the disbondment results held up in service.

---FAQ---

Q: What is the difference between wrapping and cladding?

A: Cladding presses a die onto the pipe and extrudes the polymer around it; wrapping lays a spiral with an overlap. Cladding suits small pipe where the circumference is short; wrapping suits 12 inch and above, and it is the method used on most transmission pipe worldwide.

Q: How is the wrap pitch kept consistent?

A: Conveyor speed, pipe rotation speed and extruder output are interlocked on the PLC as one recipe per diameter. The operator selects the diameter and the three values come up together.

Q: Why use two extruders?

A: The copolymer adhesive and the polyethylene topcoat have different properties and different layer thicknesses. Metering them through separate heads gives independent control of each layer, which matters when the contract specifies both thicknesses separately.

Q: Can the same line produce two-layer coating?

A: Yes. Shut off the epoxy spray and the adhesive head, and the wrapping section continues to run. That gives a two-layer product without a second line, which is useful when a plant's order book mixes both.

Q: What layer thicknesses can it produce?

A: The thicknesses required by the standard in your contract. On a typical three-layer build-up the epoxy layer is measured in tens of micrometres, the adhesive in hundreds of micrometres and the polyethylene topcoat in millimetres, and we set the die, gap and line speed to hit your specification.

Q: What is the capacity?

A: Up to 800 m2/h of coated surface. The practical figure depends on diameter, wall thickness and how many diameter changes are in the schedule.

Q: How is the finished coating inspected?

A: By a holiday detector on the line, then by the tests named in your contract, normally coating thickness, adhesion and impact, carried out at agreed witness points with third-party inspection where required.

Q: Can you train our operators on recipe creation?

A: Yes. Training covers calling up, adjusting and saving a recipe, which is the skill that lets a plant run several diameters without depending on one experienced operator.