Screw Conveying Equipment

Screw conveying equipment is a kind of continuous bulk material handling machinery widely used in industrial,agricultural,municipal and environmental protection fields.It uses the rotating spiral blade to generate thrust,so as to transport powdery,granular,small block or viscous materials horizontally,obliquely or vertically.With the advantages of compact structure,simple operation,closed conveying and flexible layout,it has become one of the core equipment in bulk material conveying systems.

Classification of Screw Conveying Equipment

According to the structure of the spiral,screw conveying equipment is mainly divided into two categories:Shaft Screw Conveyor(Shafted Type)and Shaftless Screw Conveyor.The two types have their own characteristics and are suitable for different material and working conditions.

1.Shaft Screw Conveyor

Basic Definition

It is a classic type of screw conveying equipment,consisting of a central solid shaft,helical blades welded on the shaft,trough casing,driving device,feeding port and discharging port.It is mainly used for conveying dry,loose and free-flowing materials.

Structure&Working Principle

-Central Solid Shaft:The core component runs through the entire conveyor,and the spiral blades are firmly fixed on it to ensure stable rotation and material pushing.

-Hanger Bearings(Intermediate Hanging Bearings):For long-distance conveying,intermediate bearings are installed inside the trough to support the long central shaft,preventing bending,vibration and wear during operation.

-Trough Casing:Usually a U-shaped or tubular closed shell,which can prevent dust leakage and material scattering,ensuring environmental protection and safe operation.

-Working Principle:The motor drives the central shaft and spiral blades to rotate through the gearbox.The rotating spiral blades generate axial thrust,pushing the materials from the feeding port to the discharging port continuously,realizing mechanical conveying of materials.

Key Advantages&Disadvantages

Advantages:

-Simple overall structure,mature manufacturing process,low production and purchase cost.

-Fully closed conveying design,no dust leakage,good environmental performance,suitable for clean production scenarios.

-Stable operation,low energy consumption,suitable for long-distance continuous conveying.

-Wide adaptability to dry,loose,free-flowing powdery,granular and small block materials.

-Flexible layout,can realize horizontal,small-angle inclined conveying(≤20°).

Disadvantages:

-Easy to be wrapped and blocked by sticky,wet,fibrous or sludge materials,affecting conveying efficiency.

-Intermediate hanger bearings are vulnerable parts,which need regular maintenance,lubrication and replacement,increasing maintenance cost and downtime.

-The central shaft occupies the internal space of the trough,resulting in lower effective conveying capacity compared with shaftless type.

-Not suitable for conveying high-viscosity,easy-tangling and corrosive materials for a long time.

2.Shaftless Screw Conveyor

Basic Definition

It is a specialized screw conveying equipment improved on the basis of the shafted type.It cancels the central shaft and adopts an integral continuous helical blade,which rotates inside the U-shaped trough to convey materials.It is especially suitable for sticky,fibrous,wet and easily tangled materials.

Structure&Working Principle

-Shaftless Spiral Blade:Made of high-strength alloy steel(such as 8620 alloy,304/316 stainless steel),it is an integral continuous helical structure without a central pipe,with high strength and wear resistance.

-U-Shaped Trough:The spiral blade rotates inside the stationary U-shaped trough,and the inner wall of the trough is usually lined with wear-resistant materials(such as UHMWPE,rubber)to reduce friction and extend service life.

-Driving Device:Composed of motor and gearbox,it provides stable power for the rotation of the spiral blade,ensuring smooth conveying.

-Working Principle:The motor drives the shaftless spiral blade to rotate.The continuous spiral structure pushes the materials forward along the trough.The absence of the central shaft avoids material wrapping,realizing efficient and unobstructed conveying.

Key Advantages&Disadvantages

Advantages:

-Excellent anti-clogging and anti-winding performance:The absence of a central shaft eliminates the problem of material wrapping and blocking,which is ideal for sticky,wet,fibrous,sludge and irregularly shaped materials.

-Higher conveying capacity:The integral spiral blade utilizes the full cross-section of the trough,and the volumetric efficiency is up to 1.5 times that of the shafted screw conveyor.

-Low maintenance cost:There are no internal hanger bearings or central shaft that are easy to wear,reducing maintenance frequency,downtime and repair costs.

-Good sealing and hygiene:The fully enclosed design prevents dust,odor and material leakage,meeting environmental protection and hygiene standards(suitable for food,pharmaceutical and environmental protection fields).

-Flexible installation:It can be installed horizontally or obliquely(up to 30°–45°),adapting to different site layout requirements.

Disadvantages:

-Higher manufacturing cost:The integral shaftless spiral blade has high processing difficulty and higher cost compared with the shafted type.

-Not suitable for conveying hard,sharp and highly abrasive materials for a long time,which will accelerate the wear of the spiral blade.

-The length of a single unit is limited(usually up to 20–60m),and long-distance conveying needs special design.