Why is the mixing performance of conical twin screws better than other types?

1. Optimization of geometric structure design
(1) Tapered channel and dynamic gap
The diameter of the conical twin screw gradually decreases from the inlet to the outlet, forming a tapered channel. This design makes the material continuously subjected to the dual effects of compression and shear force during the conveying process:
Compression effect: The cross-sectional area of ​​the channel gradually decreases, resulting in an increase in material density and promoting dispersion mixing.
Shear gradient: The gap between the screw and the barrel changes along the axial direction, generating a non-uniform shear field, effectively breaking up agglomerated particles and enhancing the dispersion effect.

(2) Asymmetric arrangement and expansion of stirring range
Conical twin screws usually adopt an asymmetric arrangement (such as one large and one small screw) to expand the stirring coverage area, which is especially suitable for materials with large differences in specific gravity or mixing ratio. For example, in powder-liquid mixing, the small screw can penetrate into the low fluidity area, while the large screw improves the overall circulation efficiency.

2. Synergistic effect of compound motion modes

The conical twin screw produces a variety of material flow modes through the compound motion of revolution (rotation around the center axis of the cone) and rotation (rotation of the screw itself):

(1) Convective mixing

The screw's rotation lifts the material from the bottom spiral to the top, while the revolution drives the material to move in a circle along the cone wall, forming vertical and horizontal bidirectional convection.

Compared with traditional mixers (such as drum type), its mixing efficiency is increased by 2-3 times, and the loading factor is increased by 20-40%.

(2) Shear and diffusion mixing

The centrifugal force of the screw's revolution and rotation ejects the material radially from the spiral surface, generating high-intensity shear and decomposing agglomerates; at the same time, the material falls freely under the action of gravity, forming random diffusion.

(3) Eliminating mixing dead zones

Material accumulation is prone to occur at the bottom of traditional mixers, but the conical twin screw avoids this problem through the following designs:

The cantilever screw has no bottom bearing: it reduces mechanical obstacles and allows the bottom material to be completely stirred by the spiral.

Lifting plate structure: Some models have an inclined lifting plate at the bottom of the screw to force the dead corner material to participate in the circulation.

3. Adaptability to a wide spectrum of complex materials
(1) Compatibility with materials with different specific gravity
The tapered design and compound motion of the conical twin screw can simultaneously process light powders and high-density particles. For example, when mixing drug excipients (with a density difference of up to 10 times) in the pharmaceutical industry, uniform distribution can still be achieved.

(2) Protection of heat-sensitive materials
The mixing process is mainly convection, and shear heat generation is low, which avoids the inactivation of heat-sensitive ingredients (such as vitamins and enzymes) due to local overheating. The energy consumption is only 1/10 of that of a drum mixer, further reducing temperature rise.

(3) Multiphase mixing capability
Supports solid-solid, solid-liquid, and liquid-liquid mixing, and can even integrate spray devices to achieve humidification or reaction processes. For example, in the food industry, powder flavors and liquid pigments are mixed simultaneously.

4. Balance between energy consumption and efficiency

(1) Energy-saving design
The natural flow of materials in the conical structure reduces mechanical resistance, and with the optimized screw speed, energy consumption is reduced by 50% compared with traditional equipment.
Through CNC multi-axis linkage processing technology, the screw meshing clearance accuracy reaches micron level, reducing friction loss.

(2) High production capacity and easy maintenance
The discharge port is located at the bottom of the cone, and is equipped with a pneumatic valve to achieve rapid discharge (90% of the material can be discharged within 30 seconds), which is suitable for continuous production.
The bottom-free bearing design reduces failure points and extends the maintenance cycle to more than twice that of traditional equipment