Crushing and Grinding Machine — NSPC Series

Overview

The NSPC Series Crushing and Grinding Machine is an integrated single-pass pulverizer that converts coarse material chunks directly into fine powder — eliminating the need for a separate secondary grinder. Built around a high-speed rotor assembly with 50 to 132 movable knives on a 640 mm diameter rotor spinning at up to 2,900 rpm (knife tip speed ~97 m/s), the machine delivers throughputs from 200 to 1,000 kg/h across five models. A dual cooling system — combining a water jacket around the grinding chamber with high-volume forced-air pneumatic conveying — keeps material temperatures below the critical 60–70 °C threshold, making it particularly suited for heat-sensitive applications such as rigid and flexible PVC, chemicals, pharmaceuticals, food additives, dyes, pigments, and plastic auxiliaries. Manual hand-wheel adjustment of the knife-to-bed clearance (typically 0.2–0.8 mm) gives operators direct control over final powder particle size distribution. With a compact footprint and low specific energy consumption, the NSPC series is a reliable workhorse for compounders, masterbatch producers, and chemical processing operations requiring consistent powder output from coarse feedstock.

Technical Parameters

Output rates measured with medium-hardness material at standard 4 mm screen mesh. Actual throughput varies by material type, bulk density, and desired powder fineness.

System Configuration

Core Features

1. Integrated Single-Pass Design — Chunks to Powder in One Machine

Unlike traditional two-stage systems that require a coarse crusher followed by a fine pulverizer, the NSPC series accomplishes size reduction from coarse feed directly to finished powder in a single pass. Raw material chunks, pellets, or flakes enter through the hopper and exit as classified powder — no secondary grinder needed. This consolidated architecture reduces equipment footprint, capital expenditure, and inter-stage material handling. For PVC pipe and profile manufacturers, the machine is an ideal companion to a plastic pelletizer machine for in-house scrap regrinding and powder recovery, or can feed directly into a single-screw extruder for compounding operations.

2. Adjustable Knife Clearance for Precision Particle Size Control

The gap between the rotating knives and the fixed bed knife is adjusted via a manual hand-wheel mechanism — no tools required. Typical operating clearance ranges from 0.2 to 0.8 mm. Reducing the gap produces finer powder with a narrower particle size distribution; widening it increases throughput at the cost of coarser output. Combined with interchangeable screen mesh options (2–10 mm apertures), operators can dial in the target powder specification without changing rotor geometry. Knife clearance should be checked every 200 operating hours as part of routine preventive maintenance.

3. Dual Water + Air Cooling System Prevents Thermal Degradation

The grinding chamber is surrounded by a water jacket circulating 2–5 L/min of cooling water to extract frictional heat at the source. Simultaneously, the high-pressure blower pulls a large volume of ambient air through the grinding zone and ducting, providing convective cooling as powder is pneumatically conveyed to the cyclone separator. This dual-mode thermal management keeps material temperature below 60–70 °C during continuous operation — critical for PVC, which begins thermal degradation (dehydrochlorination, discoloration, and HCl release) above approximately 70–80 °C. For operations already using a SML series chiller in their plant, chilled water can be supplied to the water jacket for additional cooling capacity during high-ambient-temperature or extended-run scenarios.

4. High Knife Density and Tip Speed for Fine Grinding

The rotor assembly carries 50 to 132 movable knives (model-dependent) on a 640 mm diameter rotor. At the maximum speed of 2,900 rpm (PSM-500, NSPC-600, NSPC-800), knife tip speed reaches approximately 97 m/s — a velocity regime that produces fine, consistent powder through repeated shear and impact events. Each knife is manufactured from D2/SKD-11 tool steel hardened to HRC 58–62, providing a balance of wear resistance and toughness. The high knife count ensures that material encounters cutting edges at a high frequency per rotor revolution, reducing the number of recirculation cycles needed before particles pass through the screen mesh.

5. Replaceable and Re-Sharpenable Knives for Low Consumable Cost

All movable and fixed knives are designed for multiple resharpening cycles — typically 3–5 resharpenings per knife set before replacement is needed. With D2/SKD-11 tool steel construction, knives typically achieve 300–500 operating hours between sharpening cycles when processing medium-hardness materials. Sharpening can be performed on a standard surface grinder by the operator or local tool shop; replacement knives are stocked as standard spare parts. This design philosophy eliminates the hidden cost of disposable single-use blades common in lower-tier pulverizers. For operations processing highly filled or abrasive formulations, knife life can be benchmarked during the first production run and resharpening intervals adjusted accordingly.

6. Wide Material Compatibility Across Industries

The NSPC series handles a broad spectrum of materials: rigid PVC (uPVC), flexible PVC (plasticized), chemicals, pharmaceuticals, food additives, dyes, pigments, and plastic auxiliaries. The combination of adjustable knife clearance, interchangeable screen mesh, and dual cooling makes it adaptable to materials with varying hardness, toughness, and thermal sensitivity. For PVC compounders producing PVC pipe extrusion feedstock, the machine grinds regrind and scrap back into powder form for reintroduction into the dry blend — supporting closed-loop material utilization. Similarly, roof tile extrusion line operations benefit from in-house scrap pulverizing to minimize virgin material consumption.

7. Compact Footprint with High Output-to-Space Ratio

Despite its integrated single-pass architecture, the NSPC series maintains a remarkably compact footprint. The NSPC-1000 — delivering 500–700 kg/h — occupies just 1,900 × 1,350 mm of floor space (approximately 2.6 m²). The largest model, NSPC-1300, produces 700–1,000 kg/h within 1,900 × 1,500 mm. This space efficiency simplifies plant layout integration, especially in existing facilities where floor area is constrained. The machine's self-contained design (built-in blower, cyclone, and rotary valve) means no external conveying towers or separate classification equipment is required. For complete production line planning, Chenxing also supplies upstream plastic heating mixers and hopper dryers, as well as downstream auxiliary equipment including a vacuum conveyor loader for dust-free powder transfer. Browse our full auxiliary machines catalog for complementary equipment.

Production Process

Step 1 — Material Feeding: Coarse material chunks, pellets, or flakes are gravity-fed through the enlarged hopper (opening sizes from 530×250 mm to 1330×310 mm depending on model) directly into the grinding chamber. No pre-crushing or size reduction step is required for feedstock within the machine's intake capacity.

Step 2 — Initial Crushing: As material enters the grinding zone, the high-speed rotating knives shear feedstock against the fixed bed knife. This primary shear action fractures large pieces into smaller fragments, initiating the size reduction process. The manual hand-wheel mechanism sets the knife-to-bed clearance (typically 0.2–0.8 mm), which defines the primary shear gap and influences downstream particle size distribution.

Step 3 — Fine Grinding: Fragments are repeatedly impacted and sheared by the rotor's moving knives in the high-speed zone (2,450–2,900 rpm, knife tip speed ~97 m/s at maximum RPM). The high knife density — 50 to 132 knives across the rotor width — ensures material encounters cutting edges at high frequency per rotation, progressively reducing particle size through successive impact events. The water jacket circulating 2–5 L/min of cooling water extracts frictional heat generated during this intensive grinding phase.

Step 4 — Particle Classification: Ground material is forced against the cylindrical screen mesh (4 mm standard aperture) surrounding the rotor. Particles smaller than the mesh opening pass through and exit the grinding chamber; oversize particles are retained for further grinding cycles. Interchangeable mesh sizes (2–10 mm optional) allow operators to set the maximum particle size for a given application. Screen condition should be inspected weekly — worn or punctured mesh permits oversize particles to bypass classification.

Step 5 — Pneumatic Conveying & Air Cooling: The high-pressure blower (5.5–15 kW) creates negative pressure that pulls classified powder through ducting toward the cyclone separator. The high-volume airstream simultaneously provides convective cooling, working in tandem with the water jacket to maintain material temperature below the 60–70 °C threshold. This dual cooling is essential for preventing thermal degradation in PVC and other heat-sensitive materials.

Step 6 — Cyclone Separation & Discharge: Powder and air enter the cyclone separator tangentially. Centrifugal force drives powder particles to the cyclone wall where they lose velocity and drop to the bottom, while clean air exits through the top. The rotary airlock valve (0.75–1.1 kW) at the cyclone base provides a continuous sealed discharge into the collection bag or bin without allowing dust to escape or ambient air to backflow into the system. For operations requiring automated material transfer, a pellet vacuum loader can be integrated at the collection point for conveying finished powder to downstream storage, mixing, or extrusion equipment.

Frequently Asked Questions

Q1: How does the dual water + air cooling system prevent PVC thermal degradation during grinding?

PVC begins thermal degradation above approximately 70–80 °C, releasing HCl gas, causing discoloration (yellowing to browning), and compromising mechanical properties of the final product. The NSPC series addresses this through two simultaneous cooling mechanisms. First, a water jacket surrounding the grinding chamber circulates 2–5 L/min of cooling water, extracting frictional heat directly at the rotor-stator interface where shear heating is most intense. Second, the high-pressure blower pulls a large volume of ambient air through the grinding zone, providing convective cooling as powder is pneumatically conveyed to the cyclone. Under continuous operation, this dual-mode system maintains material exit temperature below 60–70 °C — safely under the degradation threshold. Operators should monitor cooling water outlet temperature: a rise exceeding 15–20 °C above inlet temperature signals that flow rate should be increased or that the water jacket requires descaling. For plants in hot climates or running extended shifts, chilled water from an existing SML series chiller can be fed to the water jacket for additional thermal margin.

Q2: What powder particle size distribution can be achieved by adjusting knife clearance and screen mesh?

Final particle size is governed by two adjustable parameters working in combination: knife-to-bed clearance (manually set via hand-wheel, range 0.2–0.8 mm) and screen mesh aperture (standard 4 mm, optional 2–10 mm). Reducing knife clearance to 0.2–0.3 mm increases shear intensity and produces a finer, narrower particle size distribution. Widening to 0.6–0.8 mm favors throughput at the cost of coarser output. The screen mesh acts as the absolute classifier — only particles smaller than the mesh opening exit the grinding chamber. With a 0.3 mm knife gap and 2 mm mesh, operators typically achieve a D50 of approximately 150–250 µm for rigid PVC. With a 0.6 mm gap and 4 mm mesh, D50 shifts to roughly 400–600 µm. Actual distribution curves depend on material brittleness: rigid PVC fractures more readily than flexible PVC, producing finer powder at equivalent settings. We recommend customers run a trial batch to map their specific material's knife-gap-to-particle-size relationship for process documentation.

Q3: What is the knife service life when grinding rigid vs. flexible PVC, and how often is resharpening needed?

Knife service life varies significantly between rigid PVC (uPVC, brittle, higher hardness) and flexible PVC (plasticized, tougher, more abrasive on cutting edges due to filler content). For rigid PVC, D2/SKD-11 knives typically achieve 400–500 operating hours between resharpening cycles. For flexible PVC — especially formulations with calcium carbonate filler loading above 20 phr — knife life drops to approximately 300–400 hours due to increased abrasive wear. Each knife set supports 3–5 resharpening cycles before reaching minimum dimensional tolerance and requiring replacement. Operators should inspect knife edge condition every 200 hours as a preventive measure: a rounded or chipped edge increases power draw, broadens particle size distribution, and generates excess frictional heat. Sharpening is performed on a standard surface grinder — no specialized tooling needed. Chenxing stocks replacement knife sets for all NSPC models with typical lead time of 3–5 working days for standard D2/SKD-11 specification.

Q4: How does rotor speed (2,450 vs. 2,900 rpm) affect output rate and powder fineness?

Rotor speed directly influences two competing performance metrics: throughput and powder fineness. At 2,900 rpm (PSM-500, NSPC-600, NSPC-800), knife tip speed reaches approximately 97 m/s — calculated as (π × 0.64 m × 2,900) / 60. This high tip speed generates intense shear and impact forces, producing finer powder but at moderately lower throughput due to increased recirculation within the grinding chamber. At 2,450 rpm (NSPC-1000, NSPC-1300), tip speed drops to approximately 82 m/s. The reduced impact energy favors higher throughput — roughly 15–25% more output compared to equivalent rotor-width machines at 2,900 rpm — but yields a slightly coarser particle size distribution at the same knife clearance and screen mesh settings. For operations prioritizing throughput (e.g., PVC recycling for high-output single-screw extruder feedstock), the 2,450 rpm configuration with wider knife clearance provides the best kg/kWh efficiency. For fine-powder applications (e.g., masterbatch or chemical processing where D50 below 200 µm is required), the 2,900 rpm configuration with tight knife clearance is recommended. Optional VFD (variable frequency drive) can be specified to allow speed adjustment within a ±15% range for process optimization without mechanical pulley changes.

Q5: What is the typical energy consumption per ton (kWh/ton), and how does knife sharpness affect it?

Specific energy consumption for rigid PVC grinding on the NSPC series ranges from approximately 120 to 200 kWh per metric ton, varying by model size, material hardness, and desired fineness. At its nominal operating point, the NSPC-1000 delivering 600 kg/h at 2,450 rpm draws approximately 140–160 kWh/ton (main motor 75 kW + blower 7.5–11 kW + rotary valve 1.1 kW). The smaller NSPC-600 at 375 kg/h and 2,900 rpm trends toward the higher end at 170–200 kWh/ton due to lower thermal efficiency at smaller scale. Knife sharpness has a measurable impact: dull knives can increase energy consumption by 15–25% because rounded edges deform rather than cut material, converting more mechanical energy into waste heat. This inefficiency cascades — higher heat load forces the cooling system to work harder, potentially pushing material temperature toward the degradation threshold. Operators should track motor amperage draw at steady-state production as a proxy for knife condition: a gradual upward drift of 8–12% above baseline at constant throughput signals that resharpening is due. All NSPC drive motors are IE3 premium efficiency as standard, with IE4 available on request for energy-intensive operations. For cost benchmarking, multiply your local industrial electricity tariff by 0.16 kWh/kg as a conservative planning figure for medium-hardness materials with sharp knives and standard 4 mm mesh.

Why Choose Chenxing

Proven Pulverizer Platform. The NSPC series has been deployed across chemical, pharmaceutical, food additive, and PVC processing facilities worldwide. Each machine is factory-run with customer-supplied material samples before shipment, validating throughput, particle size distribution, and thermal performance against your specifications. Browse our complete product catalog for the full range of size reduction and auxiliary equipment.

Integrated Ecosystem. Chenxing manufactures the complete upstream and downstream equipment chain for plastics and chemical processing — from plastic heating mixers for dry blending and hopper dryers for moisture control, through single-screw extruders, pelletizing lines, PVC pipe extrusion lines, roof tile extrusion lines, pipe coilers, and embossing machines. A single-source supplier simplifies commissioning, service, and spare parts management.

Material Recovery Expertise. For operations recycling post-industrial PVC scrap, Chenxing offers integrated shredder-extruder recycling solutions that pair coarse shredding with the NSPC series pulverizer for closed-loop powder recovery — reducing virgin material consumption and waste disposal costs.

Application-Specific Configuration. Knife material grade, screen mesh aperture, motor power selection (single or dual rating), cooling system specification, and control panel features are configured per order — not limited to a fixed catalog offering. Visit our solutions page for application-specific configuration examples and case studies.

Global Support. Chenxing Machinery, headquartered in Zhangjiagang City, Jiangsu Province, provides remote commissioning guidance via video call, optional on-site technician dispatch for installation and training, and lifetime technical support. Read about us for company history and manufacturing capabilities, and follow our news page for the latest product updates and trade show schedules.

Start Your Inquiry in 4 Steps

Step 1 — Tell Us Your Material: Specify your feedstock — material type (PVC, chemical, food additive, dye, pigment, etc.), form (chunks, pellets, flakes, regrind), approximate input size, and any heat sensitivity constraints (maximum allowable processing temperature).

Step 2 — Define Your Output Target: Desired throughput in kg/h, target powder particle size (D50 or mesh specification), and preferred model range (PSM-500 through NSPC-1300).

Step 3 — Receive a Custom Proposal: Our engineering team reviews your requirements and provides a tailored configuration — model recommendation, knife clearance setting, screen mesh specification, motor power selection, and auxiliary equipment recommendations — typically within 24 hours.

Step 4 — Validate with a Sample Run: Optionally send 50–100 kg of your feedstock for a trial grinding run at our Zhangjiagang factory. We record throughput data, particle size distribution, power consumption, and exit temperature for your evaluation before commitment.

Contact Nicole directly:

• Phone WeChat WhatsApp: +8615951187228

• Email: ceo@cxsljx.com

Or visit our contact page for the full inquiry form. We respond to all inquiries within one business day.