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HomePPR Pipe Extrusion Line
A PPR pipe extrusion line melts polypropylene random copolymer pellets, forms them through a pipe die and sizing sleeve, and holds the diameter under vacuum while the wall cools. Our lines cover 20 mm to 160 mm at 100 to 500 kg per hour. The pipe carries hot water at pressure for decades, and that single requirement shapes everything upstream of it.
Cooling is where PPR differs from every other pipe on a factory floor. Polypropylene crystallizes as it solidifies, and how fast you take the heat out decides the crystal structure, which decides how the pipe behaves at 70°C twenty years later. Cool too quickly to gain line speed and the pipe passes every dimensional check while losing long-term pressure rating, a fault no incoming inspection will ever find.
Tell us the diameter range, whether the pipe is single-layer or glass-fiber reinforced, and your output target. Those three answers set the extruder model, the number of extruders and the cooling length before anything else is specified.
Single-Layer or Glass-Fiber Reinforced: Two Constructions
PPR pipe divides into two constructions, and the difference decides whether the line needs one extruder or two. It is worth settling first:
| Single-layer PPR | PPR-GF-PPR | |
|---|---|---|
| Structure | One homogeneous wall | Glass-fiber reinforced middle layer between two PPR walls |
| Extruders | One | Main plus co-extruder |
| Thermal expansion | Significant, needs expansion loops | Substantially reduced |
| Typical use | Domestic hot and cold water | Long runs, central heating, exposed pipework |
Thermal expansion is the practical reason the reinforced type exists. A long single-layer PPR run in a heating system moves enough that the installer has to design for it; a glass-fiber core holds the pipe closer to its installed length. The same co-extruder also applies a colored marking stripe, so a producer adding the second extruder for reinforcement usually gains identification marking at the same time.
What a PPR Pipe Line Produces
One line covers a range of piping systems, separated by diameter and wall series rather than by the machine:
- Domestic hot and cold water pipe. The core product, usually 20 mm to 63 mm and the strongest case for twin-strand extrusion.
- Central heating and HVAC pipework. Where glass-fiber reinforcement earns its cost.
- Chemical and industrial fluid transport. Wall series selected against temperature and pressure together.
- Industrial and agricultural irrigation. Larger diameters, lower pressure class.
- Food-grade and medical piping systems. Where PPR is chosen for chemical stability rather than temperature.
Two optional modules change the economics rather than the product. A gravimetric dosing system stabilizes pipe weight and typically saves 3 to 5 percent of raw material, which on a continuous line pays back faster than most other upgrades. Twin-strand extrusion doubles output on pipes up to 63 mm by running two strands from one extruder, because at small diameters the extruder has melt capacity the cooling tank cannot use.
How PPR Pipe Is Made
A complete PPR pipe production line runs six stations, each sized against the largest diameter in your range rather than the most common one:
- Drying and feeding. Pellets are dried and conveyed automatically, with optional gravimetric dosing. Feed consistency is what holds pipe weight per meter, and pipe weight per meter is where raw material cost is won or lost.
- Single screw extruder. Four sizes from SJ65/33 to SJ100/33, all at 33:1 length to diameter ratio. The long screw is deliberate: polypropylene needs a gradual melt profile more than it needs high shear, and multi-zone PID control keeps each barrel section within its own band.
- Pipe die and sizing sleeve. A spiral die distributes melt evenly around the circumference. A co-extruder can feed a glass-fiber middle layer or a marking stripe into the same die head.
- Vacuum calibration and spray cooling. Multi-stage vacuum sets the outside diameter against the sizing sleeve, then spray cooling takes heat out of the wall progressively. This station carries the crystallization question, which is why we size it against wall thickness rather than against target output.
- Servo haul-off. Closed-loop servo control matched to extruder output. Line speed runs 15 m/min on 20 mm pipe down to 8 m/min at 160 mm, and the difference is cooling, not extruder capacity.
- Planetary cutter and stacker. Clean, dust-free cutting to fixed length, then a semi-automatic stacker. In-line socketing can be added so pipe leaves the line ready to join.
All stations run from one PC and PLC integrated control platform with recipe storage, so a diameter changeover is recalled rather than dialed in again. We also supply the same downstream philosophy on our HDPE and rigid PVC pipe lines, which matters if you are planning more than one product line in the same plant.
FAQ
What is a PPR pipe extrusion line?
It melts polypropylene random copolymer pellets and forms them through a pipe die into pressure pipe, sized under vacuum and cooled progressively. Six stations, from drying to cutting and stacking.
What diameter and output can one line cover?
Four models span 20 mm to 160 mm at 100 to 500 kg per hour. Each model covers a diameter band, so the line is chosen by the largest pipe you intend to run.
Why does cooling matter more on PPR than on other pipe?
Because polypropylene crystallizes as it cools, and the crystal structure sets long-term pressure performance at temperature. Cooling too fast for line speed costs service life without affecting any dimension.
What is PPR-GF-PPR pipe?
A three-layer pipe with a glass-fiber reinforced middle layer, produced with a co-extruder. It expands far less than single-layer PPR, which matters on long heating runs and exposed pipework.
When is twin-strand extrusion worth it?
On pipe up to 63 mm. At small diameters the extruder has melt capacity the cooling tank cannot absorb, so a second strand uses output that would otherwise sit idle and roughly doubles productivity.
What do you need to quote a PPR line?
Three things: the diameter range, single-layer or reinforced, and the output target. Tell us whether you need in-line socketing and we will specify the downstream stations with the line.
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