Conductive Paddle Dryer with Self-Cleaning Wedge Blades | Indirect Heating Sludge Drying Machine

The conducting type paddle dryer (hollow paddle dryer) is a horizontal, agitated continuous drying machine built around indirect heat conduction. The main body consists of a jacketed shell with a hollow shaft inside, densely fitted with wedge-shaped hollow paddles. Heat medium is fed simultaneously through rotary joints into both the shell jacket and the hollow paddle shaft, transferring heat to the material through the metal wall for efficient, continuous drying.

Thanks to its high thermal efficiency, strong self-cleaning capability and wide material adaptability, the dryer is widely used in environmental protection, chemical, food, pharmaceutical, petrochemical and metallurgical industries. It handles paste, granular, powder and slurry materials for drying, cooling, heating, sterilization, reaction and low-temperature calcination.

• High thermal efficiency, significant energy saving: indirect conduction heating keeps all heat transfer surfaces covered by material; heat utilization reaches 80%~90%, saving 30%~50% energy compared with hot air dryers.
• Wedge self-cleaning design: the special wedge-shaped paddles generate alternating compression and expansion during rotation, self-cleaning the heat transfer surface and effectively handling sticky, wall-adhering materials.
• Wide material applicability: handles paste, granular, powder and slurry materials; one machine performs drying, cooling, heating, sterilization, reaction and low-temperature calcination.
• Fully enclosed, clean operation: no dust leakage, small exhaust volume and low contamination risk, meeting environmental and GMP requirements for pharmaceutical and food industries.
• Gentle low-speed agitation: paddle shaft speed of only 3~30 RPM protects crystal structure and particle shape, suitable for heat-sensitive and fragile materials.
• High operational flexibility: residence time is adjustable through feed rate, shaft speed and baffle height; stable operation with low maintenance cost.

During operation, heat medium (saturated steam, thermal oil or hot water) continuously enters the hollow main shaft and wedge paddles through rotary joints, while the shell jacket is heated simultaneously, forming a dual-channel heating surface. The hollow paddle shaft rotates at low speed under the drive system, and material fed from the inlet is continuously stirred and conveyed toward the outlet.

The special wedge structure makes the material alternately compressed and expanded, producing strong shear and dispersion, constantly renewing the material on the heat transfer surface to enhance heat transfer and realize self-cleaning, preventing sticking and scaling. An adjustable baffle at the outlet maintains the material level so the heat transfer surface is fully covered. Material moves in plug flow with uniform, controllable residence time, giving consistent final moisture content. Vapor is discharged through the top vent, dedusted and condensed; the whole process runs fully enclosed with no dust leakage.

Note: the above parameters are industry reference values; evaporation intensity is based on water. Actual capacity depends on initial and target moisture content, material properties and heat medium temperature. Please provide material parameters for a tailored selection proposal.

The above data are measured on industrial sites; actual results vary with material properties and process conditions.

• Vs. drum and flash dryers: the paddle dryer uses indirect conduction with 80%~90% thermal efficiency, ideal for paste, high-moisture and high-viscosity materials, fully enclosed with no dust. For sludge and filter cake, the paddle dryer is the preferred choice.
• Material forms and viscosity: handles paste, granular, powder and slurry materials with viscosity up to 500,000 cP (e.g. petroleum sludge); vacuum or closed-loop systems are available for solvent-containing or heat-sensitive materials.
• Heat media and temperature: saturated steam (150~200°C), thermal oil (up to 320°C) or hot water (80~100°C); design temperature range -40°C to 320°C; cooling water can also be used for cooling operations.
• Material options: carbon steel or 304 stainless steel as standard; 316L, 2205 duplex steel, Hastelloy and titanium available; rubber or plastic lining and Teflon coating available for anti-corrosion.
• Operating cost: only 1.2~1.5 kg of steam per kg of water evaporated (vs 2.5~3.5 kg for hot air drying); motor power 2.2~90 kW; small exhaust volume further lowers environmental operating cost.
• Vacuum and closed-loop options: the vacuum type operates at 40~80°C for heat-sensitive or solvent-containing materials with solvent recovery; nitrogen circulation suits oxidation-prone and VOC-containing materials with zero emission.

We provide full-process service from material testing, solution design, manufacturing, installation and commissioning to operator training. Customers can send material samples for lab pilot tests to obtain real drying data and a targeted selection proposal.

Key components use internationally renowned brands (SKF/NSK bearings, Siemens/ABB motors, Schneider electric components) to ensure long-term stable operation. Standard models are delivered within 45~60 working days, customized models within 60~90 working days, with a 12-month warranty and lifetime technical support.