Small Diameter 3LPE Coating Machine DN57-325 mm Cladding Type

Small pipe is loaded in bundles and separated onto the conveyor. Parallel blast heads clean the surface; each head is set so the abrasive hits at an angle that reduces collision with returning shot and therefore reduces abrasive consumption. Dust goes through the same three-stage chain used on our larger lines. Pipe is purged and end-masked, then heated by induction. Epoxy powder is sprayed, adhesive and polyethylene are extruded through a vacuum-assisted cladding die, and the coated pipe passes an air pre-cooling zone before water spray, which is the step that prevents surface water marks. The joint is cut, the end is bevelled, a holiday detector sweeps the coating, and the pipe is bundled. On masked ends the bevelling cycle is around 40 seconds a pipe; leave the ends unmasked and the same operation takes roughly two minutes.

1. Pipe diameter: DN57-325mm (2-12 Inch)
2. Processing capacity: ≥250m²/h
3. Cleaning level: ≥Sa2.5
4. Materials for production: epoxy powder, adhesive, polyethylene

Standards Compliance

GB/T 23257 applies to domestic Chinese orders; ISO 21809-1 and DIN 30670 are used where the buyer's contract names an international specification; surface preparation follows ISO 8501-1. Small diameter pipe often falls under a distribution rather than a transmission specification, and the layer thickness and test frequency differ accordingly, so we confirm which regime applies before quoting.

Applications

City gas distribution pipe; branch and service lines; small bore water and irrigation pipe; firefighting risers and mains; compressed air and industrial utility pipe; cable protection tube where coating is specified. The common commercial pattern for this size is many short runs rather than one long project, so buyers here care about diameter changeover time and about how quickly the line can be stopped and restarted without losing the blasted surface.

Service & Support

Commissioning is supervised by 2 engineers over about 15 days for a compact line. Because this size is usually run by smaller teams, training emphasises changeover and fault diagnosis as much as normal operation. Documentation is in English. Critical wear parts ship by air within 72 hours. Main machine warranty 12 months and drive train 24 months, with a consumable package available for the first two years.

Why Choose Qingdao Huashida

Small diameter lines are where abrasive consumption, not machine price, decides the running cost, and that is a design question rather than a purchasing question. Our blast head geometry is set so abrasive meets the pipe at an angle that limits collision with returning shot, which is the single biggest lever on shot consumption. We hold 58 invention patents and 38 software copyrights, and our anti-corrosion equipment carries a Shandong Province First-Set Technical Equipment award. For a plant running several small diameters, we will also quote a shared tooling set so that changeover does not mean buying a new die per size.

---FAQ---

Q: Why cladding instead of spiral wrapping at this size?

A: Below roughly 12 inch, the pipe circumference is too small for spiral wrapping to lay a consistent overlapping seam. Cladding through a vacuum-assisted die gives a smoother and more repeatable result, and it is faster per pipe.

Q: Why are there four or six blast heads?

A: Because blasting small pipe is much quicker than coating it. Running several heads in parallel lets the blaster stay ahead of the coating station, and it also lets you shut the blaster down between campaigns instead of running it at part load.

Q: What causes water marks on small pipe coating?

A: Water hitting hot polyethylene. We put an air pre-cooling section before the water spray so the surface temperature drops gradually, which removes the mark. It is a small detail that shows up immediately when a coated pipe is cut for inspection.

Q: Can the line handle several diameters in a day?

A: Yes. Changeover is a die and seal change with a stored recipe, normally well under an hour, so a daily schedule mixing two or three sizes is practical.

Q: What is the advantage of the pickling and phosphating option?

A: After blasting, a bare steel surface begins to oxidise within about five hours. Pickling and phosphating leaves a protective film that extends that window to two or three days, which matters when the coating station has to stop for a changeover or a maintenance call.

Q: How much floor space does it need?

A: Noticeably less than a large diameter line, and no blast pit in most configurations, so an existing bay is often sufficient. Send us your floor plan and we will confirm whether it fits.

Q: Is the machine suitable for a plant with limited technical staff?

A: Yes. The PLC stores a recipe for each diameter so the operator calls up a setting instead of tuning by hand, and training covers changeover and the common faults rather than only normal running.

Q: What is the price level?

A: Price follows the number of blast heads, the diameter range and the options selected, so it is quoted per configuration. Send your size mix and target hourly pipe count and we will return a firm figure within three working days.