I. General Design and Working Process

The two-shaft vibrating screen (linear vibrating screen) uses two shafts rotating synchronously in opposite directions to create an exciting force that drives the screen box in a linear reciprocating motion. Material enters from the loading end, moves in linear jumps along the screening surface, fine particles pass through the screen holes becoming the undersize product, and coarse particles are discharged from the unloading end as the oversize product, ensuring highly efficient continuous screening.

II. Main Working Principles

1. Two-shaft Excitation System

Mechanism of generating exciting force:

• Two eccentric shafts (or two vibrating motors) are symmetrically arranged and rotate synchronously in opposite directions through a gear transmission.
• The horizontal components of the centrifugal forces mutually cancel out, while the vertical components add up.
• The resulting exciting force causes the screen box to perform an approximately linear reciprocating motion.
• Magnitude of exciting force: F = m·e·ω² (m = mass of eccentric block, e = eccentricity, ω = angular velocity)

Adjustment of vibration parameters:

• Amplitude: 3-8 mm, adjusted by changing the mass or eccentricity of the eccentric blocks.
• Frequency: 960-1500 rpm, determined by the motor speed.
• Vibration direction angle: 30°-60°, affects the movement trajectory and material transport speed.
• Throwing intensity: 2.5-4.5g, ensures complete stratification and screening of the material.

2. Mechanism of Material Movement and Screening

Forms of movement:

• Throwing movement: when the vibration acceleration exceeds gravity, the material is thrown off the screening surface, loosens and rearranges, promoting stratification and screening.
• Sliding movement: when the vibration acceleration is less than gravity, the material slides along the screening surface, suitable for sticky materials.
• Mixed movement: in actual operation, both types of movement alternate, ensuring a balance between screening efficiency and transport speed.

Screening process:

• Stratification phase: under vibration, fine particles settle to the lower layer, coarse particles rise to the upper layer.
• Screening phase: fine particles in the lower layer approach the screening surface and pass through the holes during the throwing movement.
• Transport phase: un-screened coarse particles continue moving forward, the material layer gradually thins and is eventually discharged from the unloading end.

Key influencing factors:

• Material characteristics (particle size distribution, moisture, stickiness)
• Vibration parameters (amplitude, frequency, direction angle)
• Screening surface parameters (inclination angle, hole size, material)
• Operating conditions (feed quantity, material layer thickness)

3. Configuration of Screening Surface and Holes

Selection of screening surface material:

• Metal woven mesh: fine screening, holes 0.5-12 mm, high open area ratio.
• Perforated steel plate: coarse and medium screening, holes 5-100 mm, high strength.
• Polyurethane mesh: wear-resistant and corrosion-resistant, holes 1-50 mm.
• Rubber mesh: good elasticity, reduces noise, suitable for wet and sticky materials.
• Stainless steel mesh: corrosion-resistant, for food and pharmaceutical industries.

Screening surface parameters:

• Inclination angle: 0°-15°, small angle ensures high screening accuracy, large angle — high productivity.
• Number of layers: one layer yields 2 fractions, two layers — 3 fractions, up to 4 layers maximum.