Pulp & Paper .

Multi-stage helical gearboxes from the CGC ZSY/JSC series with a double-helical output pair transmit torque to the main rolls (couch roll, press roll). Double-helical gears cancel axial forces and run quietly at pitch-line speeds of 15–25 m/s — critical for continuous duty. They operate with electronic section synchronization via the HV inverter and precision encoders at 8,192 ppr.

• Reduction ratio 8–40
• Output torque 30–250 kN·m
• Service factor ≥ 2.0 for S1 continuous duty
• Forced circulating lubrication with an oil cooler
• Angular positioning accuracy via an incremental encoder

The dryer section of a PM holds 30–80 steam cylinders 1.5–1.8 m in diameter, grouped into 4–8 sections. Each section has its own gearbox and motor with independent speed control — this compensates for web shrinkage as it dries. The environment is +180 °C steam, condensate and up to 95 % humidity. Heat-resistant Viton seals and high-VI synthetic VG 320 oil are required.

• Heat-resistant seals (housing operating temperature up to +120 °C)
• Synthetic polyglycol or PAO oil VG 220–320
• IP56 with condensate protection
• Ability for precise electronic synchronization between sections

Two-stage helical or bevel-helical gearboxes transmit torque from a 1.5–7.5 MW HV motor to the refiner's main disc. A heavy start with the chamber full requires a service factor of at least 2.5 and frequently a Jiaohua YOX starting fluid coupling between the motor and the gearbox. The CGC HRC series is purpose-built for refiners and pulp refining mills.

• Reduction ratio 4–12 (motor 1,000 rpm → disc 250–500 rpm)
• Output torque up to 800 kN·m
• Service factor ≥ 2.5 for heavy starts under load
• Flange compatibility with a starting fluid coupling
• Oil pump station with a fine filter

Low-speed planetary or helical gearboxes with high reduction ratios drive rotating batch digesters and Kamyr continuous-cooking screws. Rotation speed is 0.5–4 rpm, continuous duty, with an aggressive cooking-liquor environment (NaOH, Na₂S, white liquor). Stainless or epoxy-coated housings and double seals with bearing-cavity protection are required.

• Reduction ratio 200–800
• Corrosion protection of the housing and shafts
• Double seals with leakage drainage
• Vibration and bearing temperature monitoring
• Dual-drive capability on a single driven gear

K-series (bevel-helical) and F-series (parallel-shaft) for chip conveyors, finished-paper conveyors and feed screws. A heavy start with the chip bin full requires an SF of at least 1.8. Inclined chip conveyors mandate a backstop — Tianiu NJZ series — to prevent reverse running under load weight at stop.

• K-series (bevel-helical) for heavy-duty chip conveyors
• F-series (parallel-shaft) for screws and screens
• Service factor ≥ 1.8
• Backstop mounting option on inclined conveyors
• Protection against dust and chip ingress (IP65)

Wolong YHTM/YKK asynchronous motors rated 1,500–7,500 kW at 6 or 10 kV. Continuous S1 duty; heavy start under load demands a starting torque of at least 1.8 of rated. Forced air-to-water cooling IC81W is used due to the high dissipation and compact layout. Frequently paired with a Jiaohua fluid coupling for soft starting.

• Power rating 1,500–7,500 kW, voltage 6/10 kV
• Starting torque ≥ 1.8 of rated
• Forced IC81W cooling (air-to-water)
• Insulated bearing on the non-coupling end
• Pt100 RTDs in windings and bearings

Wolong YE3/YVF low-voltage asynchronous motors with independent forced ventilation, rated 75–1,500 kW. Operated via VFD in torque/speed control with ±0.01 % accuracy — critical for section synchronization as the web shrinks. Class H insulation and inverter-duty design (NEMA MG1 Part 31) are mandatory. An 8,192-ppr encoder is mounted on the free shaft end.

• Class H insulation for inverter-duty operation
• Independent forced ventilation (decoupled from motor speed)
• Optical encoder, ≥ 8,192 ppr
• Speed-holding accuracy ±0.01 %
• IP55 minimum, protection from water mist of the forming section

The dryer-section environment is +60 °C steam at the machine frame and 70–95 % humidity. Dryer-section motors need reinforced sealing and anti-condensation winding heaters for downtime to prevent moisture build-up. The Wolong YBK3 (explosion-proof) series is used in zones with combustible dust or solvent vapors at specialty plants.

• Anti-condensation winding heaters during downtime
• IP56 with additional terminal box protection
• Class H insulation with class F thermal margin
• Vibration-resistant mounting (calender roll vibration)

Pulp stock pumps (medium- and high-consistency), forming-section vacuum pumps, recovery boiler ID fans, chemical mixers — these use standard Wolong YE3/YE4 asynchronous motors at IE3/IE4 efficiency. Continuous S1 duty, ratings 30–800 kW. Vacuum pumps require a reinforced bearing for the radial load from the pulley.

• IE3 or IE4 efficiency class
• Continuous S1 duty (24/7)
• Reinforced bearings for belt drives (where applicable)
• IP55 protection class against chemicals and splashes

Huawu YPZ2/YWZ5 electrohydraulic disc brakes are mounted on the reel drum and operate in two modes: controlled braking (web tension control during winding) and emergency stop. On web break the brakes engage within 0.15–0.3 s, stopping the roll without surface slip. For 40–60 tonne rolls, certification and a calculated torque margin are mandatory.

• Brake torque 5–50 kN·m with a 1.75 margin over calculated
• Response time ≤ 0.3 s
• Proportional control capability for controlled braking
• IP55 protection class, heat resistance up to +80 °C
• Pad wear monitoring (limit switch)

On web break or overload trip, the whole machine (or the affected section) must stop within 5–10 seconds to prevent wet stock from wrapping around the rolls. Jingu HSF / Huawu HW disc brakes with hydraulic clamping are mounted on the section's drive shaft. They are triggered from the machine PLC via the emergency-brake hydraulic station.

• Hydraulic clamp with spring-applied engagement
• Response time 0.15–0.3 s
• Electronic position and pressure monitoring
• Compatibility with the PM PLC system
• UPS backup in case of power loss

TKT/TKK shoe brakes with an electrohydraulic thruster hold the chip conveyor at stop and prevent involuntary reverse running under load weight. On long inclined conveyors they are used together with Tianiu NJZ backstops for redundant protection.

• Electrohydraulic thruster Ed-50 to Ed-301
• Combined operation with a backstop (redundant protection)
• Manual brake release for service
• Protection against chip dust (IP65)

The unwinder at the head of the slitter line uses proportional brakes that maintain web tension at 50–500 N/m across a wide range of machine speeds. Disc brakes with proportional control via a servo valve or electromagnetic powder clutch-brakes are used. The Huawu YWZ series with proportional control suits the controlled-braking mode.

• Proportional control via 4–20 mA or a servo valve
• Characteristic linearity ±5 %
• Thermal margin for continuous controlled-braking duty
• Compatibility with the web tension control system

Yongjing GIICL / Longxuan WGZ drum-type double-engagement gear couplings transmit torque up to 800 kN·m and compensate for radial, axial and angular shaft misalignment up to 1.5°. The crowned tooth shape allows operation under misalignment. Grease lubrication via a fitting with a 6-month service interval. The PM main drive requires G6.3 balancing at pitch-line speeds > 15 m/s.

• Torque 50–800 kN·m
• Angular misalignment compensation up to 1.5°
• Crowned tooth profile for operation under misalignment
• G6.3 balancing at pitch-line speeds > 15 m/s
• Grease protection against wash-out by water

Jiaohua YOX/COX hydrodynamic couplings deliver smooth starting of refiners with the chamber full and of chippers with the bin full. Rated slip of 2–3 % protects the 1.5–7.5 MW motor from overload if the refiner disc jams. Versions with a fusible plug release oil on overheat and automatically trip the drive.

• Rated slip 2–4 %
• Fusible plug with a 145–160 °C set point
• Oil fill 70–85 % of internal volume
• Thermal margin for 4–6 starts per hour
• Flange compatibility with HV motors

Jiaohua YOXp / Yongjing LX (LMC) series — pin couplings with elastic bushings for pulp stock pumps, chip conveyors and chemical mixers. They damp pulsations from high-consistency stock pumps and absorb small misalignments after thermal expansion. The service life of the elastic elements under pulp & paper conditions is at least 30,000 hours with proper alignment.

• Torque 1–125 kN·m
• Radial misalignment compensation 0.2–1.0 mm
• Pulsation damping for pumps and screws
• Elastic-element service life ≥ 30,000 h
• Resistance to fiber and chip ingress (protective cover)

The Longxuan WGZ series with an integral brake wheel combines a gear coupling and a brake drum in a single housing. Used on inclined chip and finished-product conveyors — saves space in tight layouts and simplifies service. The brake wheel is sized for TKT/TKK shoe brakes with an electrohydraulic thruster.

• Combined gear coupling and brake wheel
• Torque 5–125 kN·m
• Brake wheel diameter sized for standard TKT/TKK brakes
• G6.3 balancing for speeds > 1,000 rpm