Spiral Classifier

A screw classifier is one of the equipments used in beneficiation. Sand washers & classifiers are pieces of equipment for mechanical classification based on the principle that solid particles have different specific gravity, so precipitation speed in liquids differs.

Using a spiral blade, it can filter the powder ground in the mill, then screw the coarse material into the feed port of the mill, and discharge the filtered fine material from the overflow pipe.

Screw and spiral classifiers mainly include four types of classifiers: high weir type single helix and double helix, submerged type single helix, and double helix.


Name: Spiral Classifier
Processing capacity: 10~1785 t/d
Weight: 42188kg
Transmission motor power: 30kw
Scope of application: suitable for coarse particle classification
Structure: The transmission device is composed of a spiral body, a tank body, a lifting mechanism, a lower support (bearing bush), and a discharge valve.

In mineral processing plants, spiral classifiers are widely used to form a closed-circuit cycle with ball mills in order to divide ore sand, as well as in gravity beneficiation plants to classify ore sand and fine mud, as well as in metal beneficiation processes for particle size classification. Other operations in the operation include desliming, dehydration, and cleaning. Other advantages of the machine include its simplicity, reliability, and ease of operation.

The spiral classifier includes high weir type single screw and double screw, low weir type single screw and double screw, and submerged type single screw and double screw. High weir and submerged types predominate, with low weir types uncommon.
1.Low weir type – the overflow weir is located lower than the rotation axis of the screw.As a result of the small settlement area, in actual production, the classifier is only used for dehydrating coarse particles and washing sand ore with little mud, and it is rarely used for grinding.
2.High weir type – at the overflow end of the spiral, the overflow weir is higher than the rotating shaft, but lower than the spiral’s upper edge. This classifier has a low settlement area, a large weir type, and its weir height can be adjusted within a certain range, i.e., the settlement area can be adjusted and changed within a certain range to adjust the particle size of the classification. In the grinding process, it is a common piece of equipment.
3.Submerged – there are four spiral blades at the overflow weir end, all of which are submerged in the pulp. With this classifier, the settling area is large, the classification pool is deep, and the spiral stirring has little impact on the pulp surface. As a result, the grading surface is stable, and the overflow is large and fine. In the production of concentrators, it is often used as a classification equipment for fine grinding or secondary grinding.

Product Principle
According to the spiral classifier, the size and specific gravity of solid particles will determine the settling speed in a liquid. Coarse ore particles sink to the bottom of the tank, while fine ore particles float in the water and overflow. For mechanical grading, the screw is pushed to the upper part of the machine for discharge. The material powder milled in the mill can be graded for filtration, and then screwed into the feed inlet of the mill with the screw plate, while the filtered fine material is discharged from the overflow pipe. The body of the machine is welded to steel plates and the base is made of channel steel. Pig iron sleeves cover the inlet head and shaft head of the spiral shaft, which are wear-resistant and durable. There are two types of lifting devices: electric and manual.

Product Performance
It uses half the energy of other horizontal and vertical classifiers and the processing capacity is the same, while its classification efficiency is half that of other horizontal and vertical classifiers.
High precision, low speed
With the same grading particle size, the rotating speed of the grading wheel is 50% lower than other horizontal and vertical classifiers; Eliminates excessive particles and sieve residues in the product. For powder with Mohs hardness less than 5, the grading wheel does not wear; If the powder has Mohs hardness greater than 7, the grading wheel has a service life 5 to 8 times greater than other horizontal and vertical wheels.

Product Advantages
1. The overflow particle size can be adjusted freely between 25-90 mesh, which is convenient and flexible.
2. It is easy to operate: the spiral classifier has a simple structure and uses frequency conversion control, which simplifies operation.
3. Wide application: the equipment can be used both for classification and desliming before beneficiation. Metal and gravity beneficiation are the most common uses.
4. Maintenance is easy: due to the simple structure of the equipment, the daily operation and maintenance are relatively simple, and the equipment has a long service life and a high return on investment.

ModelSpiral diameterLength of tank(mm)Rotating speed(r/min)Power(kw)Dimension(mm)



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