What is a double shaft paddle horizontal zero gravity free mixer

The twin-shaft paddle horizontal gravity-free mixer has significant advantages in dry powder mixing, such as fast mixing speed, high uniformity, and low energy consumption. It is the core mixing equipment in the industries of dry powder mortar, chemical powder, feed, pharmaceutical excipients, etc.

The equipment agitates dry powder materials in three directions: axial, radial, and circumferential, through the counter-rotating blades of two shafts, and sprays them into the air at high speed to form a "weightlessness zone". This allows powders of different particle sizes and specific gravities to fully mix and blend during the falling process, effectively avoiding stratification and segregation. The mixing time usually takes only 1-3 minutes, and the coefficient of variation (CV value) of mixing uniformity can be controlled at ≤3%. It is especially suitable for powder mixing tasks with large ratio differences (such as 1:1000).

The equipment adopts a horizontal W-shaped cylinder structure, internally equipped with two parallel and counter-rotating mixing shafts, each equipped with paddles at a specific angle. During operation, the paddles agitate and rapidly disperse the material in three directions: axial, radial, and circumferential, forming a "weightlessness zone". This allows materials of different specific gravities and particle sizes to be fully intermixed, effectively preventing stratification and segregation. The mixing time typically takes only 1-3 minutes, with a coefficient of variation (CV value) for mixing uniformity as low as ≤3%, and energy consumption is only about 40% of that of traditional mixers.

1. Core structure and working principle

Cylinder design: W-shaped or twin U-shaped horizontal structure, optimizing material flow path and reducing mixing dead zones.

Mixing system: Blades are arranged alternately on the dual shafts, rotating in opposite directions at a constant speed (typically 40–60 rpm), creating a compound circulation motion.

Weightlessness mixing mechanism: Materials are thrown into the air to form an instantaneous weightlessness state, and are extensively mixed during the falling process, overcoming the uneven mixing caused by differences in gravity.

Drive mode: Dual gearbox synchronous combination, chain drive, or planetary reducer are commonly used to ensure synchronous and counter-rotating operation of the dual axes.

It supports solid-solid and solid-liquid (liquid content ≤20%) mixing, and can be equipped with functional modules such as spray system, jacket (heating/cooling), and flying knife crushing device.

II. Main classification

Ordinary type zero-gravity mixer

Suitable for conventional powder mixing, such as dry mortar, feed, chemical raw materials, etc.

Flying knife type zero gravity mixer

Equipped with a high-speed rotating fly knife (rotating speed ≥1400rpm), it is used to disperse fibrous materials (such as lignin and cellulose), prevent clumping, and enhance mixing uniformity.

III. Performance Advantages

✅ High mixing speed: The processing time per batch is short, with an efficiency 3–5 times higher than that of ordinary ribbon mixers;

✅ High mixing accuracy: When the solid-solid mixture is prepared at a ratio of 1:1000, the standard deviation can reach 3 to 8 parts per 100,000;

✅ Low energy consumption: The power consumption per ton of material is about 60% lower than that of traditional equipment;

✅ Wide range of applications: Capable of handling powders, granules, and viscous materials, and supporting process extensions such as heating/cooling, liquid spraying, and vacuuming;

✅ Clean discharge: Pneumatic or manual flap valve design, with a large opening structure that results in residuals of less than 0.1%.

IV. Specific applications in various dry powder materials

Building materials industry: efficient homogenization of dry powder mortar

Applicable products: thermal insulation mortar, bonding mortar, plastering mortar, flooring mortar, putty powder, concrete admixtures, etc.

Advantages: It can quickly mix components with large density differences such as vitrified microspheres, cement, and sand powder, preventing the crushing of lightweight aggregates and achieving high uniformity while maintaining their original state.

Process support: A spray system can be installed to achieve pre-dispersion of rubber powder, or a jacket can be equipped for temperature-controlled mixing.

Chemical engineering and new energy: high-precision mixing of fine powders

Applicable products: lithium battery cathode and anode materials (such as graphite, lithium cobaltate), electronic paste, magnetic powder, pigment, pesticide adjuvant, etc.

Advantages: For mixing ultra-fine powder (particle size 300–2000μm), it supports inert gas protection and vacuum operation to prevent oxidation or dust explosion.

Customization requirements: Mostly use 316L stainless steel material to meet high cleanliness and corrosion resistance requirements.

Food and feed: safe and hygienic dry powder mixing

Applicable products: milk powder, salt, essence, feed additives, premix, etc.

Advantages: The inner surface of the equipment can be polished to a roughness level of Ra≤0.4μm, meeting food-grade standards; the residual material after discharge is less than 0.1%, avoiding cross-contamination.

Compliance: Supports CIP online cleaning system to meet GMP certification requirements.

Pharmaceuticals and cosmetics: High value-added powder homogenization processing

Applicable products: medicinal excipients, traditional Chinese medicine powder, facial mask powder, toilet powder, disinfectant powder, etc.

Advantages: Gentle mixing without damaging the material structure, suitable for precise proportioning and mixing of low-dose high-activity ingredients.