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Product Description
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The SJSZ series conical twin screw extruder is purpose-built for direct PVC powder extrusion — no pre-granulation required. With six models spanning 60 to 800 kg/hr output capacity, the SJSZ line serves manufacturers producing PVC pipes, window/door profiles, WPC decking, foam boards, sheets, and PVC compound pellets. The conical screw geometry generates high compression ratio and large surface area in the feed zone, making it the industry-standard design for processing heat-sensitive PVC formulations at low screw speeds (1–45 rpm) without thermal degradation.
Chenxing Machinery has manufactured and exported conical twin screw extruders to PVC processors across Southeast Asia, the Middle East, Africa, and South America for over 15 years. From a single SJSZ-45 for a startup pipe workshop to a bank of SJSZ-92 machines feeding a high-output corrugated pipe line, every extruder is factory-tested with your formulation before shipment.
| Parameter | SJSZ-45 | SJSZ-51 | SJSZ-55 | SJSZ-65 | SJSZ-80 | SJSZ-92 |
|---|
| Screw Diameter (mm) | 45/90 | 51/105 | 55/110 | 65/132 | 80/156 | 92/188 |
| Number of Screws | 2 | 2 | 2 | 2 | 2 | 2 |
| Screw Rotation | Counter-rotating outward | ← | ← | ← | ← | ← |
| Screw Speed (rpm) | 1–45 | 1–45 | 1–45 | 1–45 | 1–34.7 | 1–34.7 |
| Screw Effective Length (mm) | 985 | 1070 | 1270 | 1430 | 1800 | 2500 |
| Main Motor Power (kW) | 15 | 18.5 | 22/30 | 37 | 55 | 110 |
| Barrel Heating Power (kW) | 12 | 18 | 18 | 24 | 36 | 86.8 |
| Heating Zones | 4 | 4 | 4 | 5 | 6 | 8 |
| Production Capacity (kg/hr) | 60–120 | 80–150 | 100–180 | 200–300 | 300–400 | 600–800 |
| Center Height (mm) | 1000 | 1000 | 1000 | 1000 | 1000 | 1200 |
| Net Weight (kg) | 2800 | 3000 | 3500 | 4000 | 5000 | 8000 |
| Dimensions L×W×H (mm) | 3200×1200×2108 | 3200×1200×2100 | 3600×1100×2100 | 4235×1520×2450 | 4750×1550×2460 | 5725×1550×2840 |
Not sure which model fits your production target? Contact our engineering team — tell us your product type, target hourly output, and PVC formulation, and we will recommend the optimal SJSZ configuration with a complete downstream equipment package.
Why conical and not parallel? PVC is shear-sensitive — it degrades above 200°C. The conical design achieves three things in one geometry: large intake volume at the feed end to accept low-bulk-density PVC dry-blend powder; progressive compression along the tapered screw length (typically 1:2.5–1:3) to compact and plasticize without excessive shear; and high discharge pressure at the smaller-diameter metering end to push melt through the die head. The result: gelation rates above 95% with melt temperature held at 170–185°C — well below the degradation threshold. For manufacturers already producing PVC corrugated pipes or WPC profiles, the SJSZ conical extruder is the natural choice.
Both screws rotate outward (away from each other at the intermeshing apex), creating a continuous C-shaped melt channel that advances material forward with minimal backflow. This counter-rotating outward configuration provides: (1) positive displacement conveying — output is proportional to screw speed, making throughput highly predictable; (2) self-wiping action — screw flight tips continuously scrape the barrel wall and the mating screw, preventing PVC stagnation and black-spot contamination; (3) narrow residence time distribution — every particle spends approximately the same time in the barrel, eliminating over-cooked material that causes surface defects on the finished product.
The SJSZ screw shaft accepts interchangeable conveying, kneading, and mixing elements in a segmented design. For rigid PVC pipe: a deep-feed conveying section followed by a long compression zone with narrow-pitch kneading blocks to maximize gelation at 80–120 kg/hr. For PVC foam board: a shorter compression section with wider-pitch mixing elements to retain blowing agent dispersion. For PVC compound granulation: reverse-flighted elements after the metering zone to create back-pressure and dispersive mixing. Chenxing Machinery provides screw configuration drawings for each application — you do not need to guess element placement. Our hot-cold mixing units are designed to feed directly into the SJSZ hopper with automatic vacuum loading.
Each barrel heating zone is independently controlled by a PID temperature module with ceramic band heaters and air-cooling fans for active cooling when barrel temperature overshoots the setpoint. Typical zone settings for rigid PVC pipe: Zone 1 (feed): 160°C → Zone 2: 165°C → Zone 3: 170°C → Zone 4 (metering): 175°C. The melt thermocouple at the adapter flange reads actual melt temperature within ±1°C, and the system automatically adjusts cooling fan speed to maintain setpoint regardless of ambient factory temperature — critical for factories in hot climates like West Africa and the Middle East.
The main motor drives the screw pair through a hardened gearbox with crowned-tooth helical gears and a torque-limiting safety coupling. If a foreign object enters the barrel, the coupling disengages before screw or gearbox damage occurs — a feature that has saved Chenxing customers thousands of dollars in avoidable repair costs. An ammeter on the control panel provides real-time motor load readout, allowing the operator to adjust feed rate before overload conditions develop.
PVC resin is pre-mixed with stabilizers (calcium-zinc or lead-based), lubricants (paraffin wax, calcium stearate), impact modifiers (CPE or acrylic), fillers (calcium carbonate, 5–30 phr), and processing aids in a Chenxing hot-cold mixer. The high-speed hot mixer heats to 110–120°C, at which point the compound is automatically discharged to the cold mixer and cooled to below 40°C before feeding into the SJSZ extruder hopper.
The cooled PVC dry-blend is transferred by vacuum loader into the extruder hopper. A gravimetric feeder (optional, recommended for SJSZ-65 and above) doses material into the feed throat at a controlled rate, maintaining a consistent fill level in the feed zone — this eliminates output fluctuation caused by irregular bridging of low-bulk-density powder in the hopper.
As the conical screws convey material forward through 4–8 heating zones, PVC particles undergo compaction in the feed zone, transition to a gel state in the compression zone, and reach full melt homogeneity in the metering zone. The counter-rotating outward screw motion generates gentle but thorough kneading action — all particles experience uniform shear history, and melt temperature at the screw tip remains at 170–185°C for rigid PVC formulations.
The homogeneous melt passes through a screen changer (80/100/120 mesh depending on product surface quality requirements) to remove any unmelted particles or contaminants, then enters the die head. Die head design — pipe die, profile die, or pelletizing die — is custom-configured per your product. The extruder's high discharge pressure (12–25 MPa) ensures consistent die flow without pulsation.
| PVC Product | Recommended SJSZ Model | Compatible Downstream Equipment |
|---|
| Rigid PVC Pipe (16–400 mm) | SJSZ-55 to SJSZ-80 | Pipe die, vacuum calibration tank, haul-off, cutter |
| Window/Door Profiles | SJSZ-65 to SJSZ-80 | Profile die, calibration table, haul-off, cutter |
| PVC Foam Board / Sheet | SJSZ-65 to SJSZ-92 | Sheet die, three-roll calender, cooling, cutter |
| WPC Decking | SJSZ-65 to SJSZ-92 | Sheet/profile die, embossing roller, cooling, cutter |
| PVC Compound Granulation | SJSZ-45 to SJSZ-92 | Pelletizing die, water-ring or strand pelletizer |
| PVC Corrugated Pipe | SJSZ-55 to SJSZ-65 | Corrugator mold track + single wall corrugated line |
Producing recycled-content PVC products? Pair the SJSZ extruder with our shredder-extruder recycling pelletizing system to turn production scrap and post-industrial PVC waste into reusable compound — reducing raw material cost by up to 30%.
| Your Production Target | Best Model | Rationale |
|---|
| Startup PVC pipe workshop, 5–10 tons/day | SJSZ-45 | 60–120 kg/hr, lowest investment, 15 kW motor |
| Small-medium pipe/profile plant, 10–20 tons/day | SJSZ-51 or SJSZ-55 | 80–180 kg/hr, balanced output and cost |
| Mid-scale PVC processor, 20–40 tons/day | SJSZ-65 | 200–300 kg/hr, 5-zone heating, 37 kW — the most popular model |
| Large-scale pipe/profile plant, 30–60 tons/day | SJSZ-80 | 300–400 kg/hr, 6 zones, suitable for 250–400 mm PVC pipe |
| High-output 24/7 production, 50–100+ tons/day | SJSZ-92 | 600–800 kg/hr, 8 zones, 110 kW — for main trunk pipe and large profiles |
Conical screws have larger intake volume at the feed end to accept low-bulk-density PVC powder, and progressive compression without excessive shear — preventing thermal degradation. Parallel twin screws with smaller feed-end diameter struggle with powder bridging and require a crammer feeder. For PVC dry-blend direct extrusion, conical geometry remains the industry standard.
With appropriate downstream tooling: rigid PVC pipes (16–400 mm), window/door profiles, WPC decking, PVC foam boards, PVC sheets, and PVC compound pellets. The extruder handles formulations with 5–30 phr calcium carbonate filler and up to 8 phr impact modifier without screw configuration changes.
MOQ is 1 complete SJSZ extruder with standard screw configuration for your application. Screw elements, barrel bushings, heating bands, and gearbox spare parts can be reordered individually with no minimum quantity. A complete PVC pipe extrusion line including downstream equipment can be ordered as a turnkey package.
All SJSZ extruders are CE certified, manufactured under ISO 9001:2015. Motors are Siemens/ABB IEC-compliant. Electrical cabinet meets IP54 protection rating. For regional certifications — UL, SASO, SONCAP, GOST — we configure compliant components during order specification. Full certification documentation is included with shipment.
Standard delivery: 55–70 working days. On-site installation and commissioning by Chenxing Machinery engineers: 7–10 working days. Free remote video guidance is available for buyers using local teams. A complete PVC pipe extrusion line including downstream equipment adds approximately 10–15 working days to delivery time.
24-month warranty on the extruder mainframe — gearbox, screw pair, barrel, and thrust bearing assembly. 12-month warranty on electrical components, heating bands, and temperature controllers. Lifetime free online technical support. Paid on-site service is available within 7 working days globally. Spare parts ship within 48 hours.
FOB price depends on model, screw configuration, motor brand, and optional accessories (gravimetric feeder, vacuum loader, screen changer, melt pump). Contact our sales team with your product type, target hourly output, and PVC formulation for a detailed quotation within 24 hours. Every quotation includes a free CAD factory layout drawing.
Floor space: approximately 4–10 m × 2–3 m depending on model. Power: 15–110 kW at 380V/50Hz three-phase. Cooling water for the feed throat: 0.5–1.5 m³/hr at 15–25°C. Compressed air: 0.6 MPa. No special foundation — a level concrete floor with vibration-damping pads is sufficient.
The screw configuration may need adjustment — foam formulations typically require wider-pitch mixing elements and a shorter compression section. Screw element changeover takes 4–6 hours. Additionally, the downstream equipment (pipe die/tank vs. sheet die/calender) must be swapped. Chenxing provides screw configuration drawings for each application.
For rigid PVC pipe production on SJSZ-65 at 250 kg/hr: approximately 0.15–0.18 kWh/kg including barrel heating. The SJSZ-92 at 700 kg/hr achieves approximately 0.14–0.16 kWh/kg due to higher throughput efficiency. Energy consumption is documented in the factory acceptance test report provided with every machine.
Every SJSZ extruder undergoes a factory acceptance test at our Zhangjiagang facility: screw assembly inspected for runout, gearbox tested under load for 4 hours, all heating zones and PID controllers calibrated, and a full production run using your specified PVC formulation (or a standard rigid PVC reference compound). Test reports and video documentation are included with shipment.
Yes, with limitations. The SJSZ handles up to 30% recycled PVC regrind blended with virgin compound. For higher recycled content (50–70%), we recommend pre-compounding the recyclate through our pelletizing system before feeding into the SJSZ extruder. This ensures consistent melt quality and prevents contaminants from reaching the die head.
Chenxing Machinery has designed, manufactured, and exported conical twin screw extruders to PVC processors worldwide since 2009. Our installed base spans pipe plants in Nigeria, profile factories in Egypt, WPC decking producers in Vietnam, and granulation lines in Saudi Arabia — giving us deep practical knowledge of PVC processing under diverse ambient conditions and raw material qualities.
Your SJSZ extruder runs a full production batch at our Zhangjiagang facility before disassembly. You attend the test in person or via live video stream. The factory acceptance test report documents: output rate (kg/hr), melt temperature stability (±3°C across a 2-hour run), motor load percentage, and gelation degree (≥95% for rigid PVC pipe). Test material can be your specified PVC formulation or a Chenxing reference compound.
Beyond the extruder itself, Chenxing provides: downstream equipment packages (pipe/profile/sheet/ pelletizing line), PVC hot-cold mixing units, CAD factory layout drawings, PVC formulation guidance with local raw material sourcing recommendations, English SOP manuals, and 5 working days of on-site operator training during commissioning.
Follow Chenxing Machinery's news page for PVC extrusion technology updates, formulation tips, and PET recycling insights. Our complete solutions overview covers the full range of plastic extrusion and recycling equipment.
Ready to launch, expand, or upgrade your PVC processing operation? Here is how we work:
You send us your requirements — product type (pipe, profile, sheet, or granulation), target hourly output, PVC formulation details, and local utility specifications (voltage, frequency)
We deliver a customized proposal within 24 hours — including recommended SJSZ model, screw configuration drawing, complete downstream equipment list, FOB price, delivery timeline, and CAD factory layout
You review and refine — our engineers iterate the configuration until it matches your exact production goals and budget
We build, test, and ship — with complete video documentation of the factory acceptance test before container loading
Or email directly: ceo@cxsljx.com
Include your product type and target hourly output for the fastest quotation turnaround. We respond to all inquiries within 24 hours.
