Pressure pipe
uPVC water pipe for PN6-PN16 municipal networks, usually Ø110-630mm to ISO 4422 or GB/T 10002.
PIPE EXTRUSION
How PVC Pipe Is Made
From compound to finished pressure pipe.
PVC pipe covers municipal water networks, drainage systems, electrical conduit and agricultural irrigation. Understanding how it is produced helps you specify the right compound, diameter range, pressure class and line output for your market.
What PVC pipe is used for
PVC pipe divides into pressure pipe, drainage pipe and conduit. Each product uses the same base polymer but different wall thickness, stabiliser package, output speed and testing standard.
Drainage & sewer pipe
PVC-U drainage pipe prioritises ring stiffness under EN 1401 or GB/T 5836 instead of pressure rating.
Electrical conduit
Grey or orange conduit to IEC 61386 uses thinner walls and higher line speed than pressure pipe.
Agricultural irrigation
Lightweight PVC irrigation pipe balances stiffness, cost and easy field installation.
Raw material: what goes into PVC pipe
Rigid PVC pipe starts from PVC dry blend or ready compound, not raw resin alone. A typical PVC-U pipe formula uses PVC resin with K-value 65-67, Ca/Zn or organic tin stabiliser, limited calcium carbonate filler, acrylic processing aid and pigment. PVC degrades rapidly above 200°C, so stabiliser is what gives the compound a useful processing window around 160-190°C. K67 is common for pressure pipe because it gives strength; K65 flows more easily for thin-wall conduit. Calcium carbonate at about 5-10 phr improves rigidity and cost, but excessive filler reduces impact strength and hydrostatic performance.
- Ready compound is simpler for new factories because formulation control is handled by the supplier.
- On-site high-speed mixing gives lower material cost and more control, but requires cooling mixer capacity and formulation knowledge.
- Moisture should stay below about 0.2%; well-stored PVC compound usually does not need pre-drying.
Production process
PVC is heat-sensitive, so the process must plasticize the compound evenly without overheating it. The line controls melt temperature, vacuum sizing, cooling rate and haul-off speed because these four points decide the pipe diameter, wall thickness and pressure performance.
Feeding
PVC compound is conveyed to the hopper by vacuum loader or bag dumping. Consistent feeding prevents pressure fluctuation at the die, which would show up as wall thickness variation.
Twin-screw plasticizing
PVC pipe is processed on a twin-screw extruder because gentle mechanical shear gives a homogeneous melt at lower temperature than a single screw. Typical screw L/D is 20:1-28:1, with barrel zones rising from about 155°C to 185°C.
Pipe die head
The melt passes through a pipe die with an outer ring and central mandrel. Spider or torpedo supports create flow paths that must re-fuse fully before the melt exits, otherwise the pipe can fail along weld lines.
Vacuum sizing
The hot pipe enters a precision sizing sleeve at about -0.04 to -0.08 MPa. Vacuum pulls the soft wall against the sleeve and fixes the outer diameter within tight tolerance.
Cooling tank
Water cooling tanks, normally 4-8m total length, remove heat gradually. Too rapid cooling creates internal stress; water temperature is usually kept around 15-25°C.
Haul-off
The caterpillar haul-off pulls pipe at a stable speed. Faster haul-off makes a thinner wall, so slip or speed fluctuation creates rejectable longitudinal wall variation.
Cutting and stacking
A planetary cutter tracks the pipe and cuts standard lengths, often 6m, without stopping the line. Pipe then transfers to a stacker or bundling table.
What the finished pipe must meet
Finished PVC pipe is checked for hydrostatic pressure resistance, Vicat softening temperature, impact strength, outside diameter, wall thickness and ovality. Pressure pipe is tested under EN ISO 1167 or GB/T 6111; drainage pipe focuses more on ring stiffness and impact. A Ø110mm PN10 PVC pressure pipe to SDR13.6 has a wall around 8.1mm, while conduit of similar diameter can be much thinner because it does not carry pressure.
Machines required
These are the core machines for a standard PVC pipe line. Output capacity scales mainly with twin-screw size: a Ø65/132 extruder may produce around 200 kg/h, while a Ø92/188 line can reach about 600 kg/h depending on compound and pipe size.
Twin Screw Extruder
Plasticizes PVC compound gently and evenly.
Pipe Die Head
Shapes the melt into a hollow pipe with the target diameter.
Vacuum Sizing & Cooling Tank
Sets the OD and removes heat without distorting the pipe.
Caterpillar Haul-off
Controls line speed and therefore wall thickness.
Planetary Cutter
Cuts rigid pipe to length while the line keeps running.
Pipe Stacker
Collects, supports and bundles finished pipe lengths.
Technical reference
Planning reference only. Final configuration depends on your target spec — share it with the engineering team for a matched proposal.
| Pipe diameter | Ø16-800mm |
|---|---|
| Wall thickness | 1.5-50mm |
| Output rate | 50-800 kg/h |
| Line speed | 0.5-8 m/min |
| Processing temperature | 160-190°C |
| Material | PVC-U / uPVC / PVC-C compound |
Ready to produce PVC pipe?
Tell us your target diameter, wall thickness, output rate and material spec. The engineering team will return a full line configuration — extruder size, die specification, downstream layout and indicative price range — within 24 hours.
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