Polygon screens

Dependent on the machine size, the sieve drum is equipped with 6 or 8 uniform fields per sieve ring.
The three basic types have diameters of 1,000 mm, 1,500 mm or 2,000 mm.
Each segment has a length of 1250 mm and up to five sieve rings can be supplied in a polygon sieve.
The pulley shaft is always continuous and is manufactured as a single piece in accordance with the length of the machine. The individual sieve rings are screwed onto it.
The central shaft is driven via an on-gear motor on the run-out side
The pulley is suspended on externally located damped return pulley supports on the run-in side, which bear the hardened polygon sieve intake ring.
It is located in the soiling-free external drum area.

This means of storage does not restrict the material feed and the incoming transport material hits the race first and then the pre-tensioned sieve areas in the machine.
Due to the inclination of the sieve pulley in the polygon sieve, the material is transported in the direction of the pulley drive where finally only lumps and foreign bodies are discharged.

The pulley motor speed monitoring is made on the run-in side via a sensor.
Optionally retainers can be retrofitted in the sieve pulley, ensuring that the sand is picked up higher and the lumps drop lower to break up and are broken by the tensioned sieve surfaces.
Delay or acceleration angles can also be screwed on in order to influence the dwell period of the sand in the sieve.

The basic chassis is lined with material conducive to sliding on the inclined surfaces. The flanges for fine and coarse grain are located inside the base plates, ensuring that the connected chutes do not collide with the shifting supports in any direction.

The spring-supported swivelling service flaps remain upright when in open position and can be used on both sides as a standard. Moreover, there are two revision flaps next to the geared motor on the drive side.

A suction flange is located above each screen ring in the cover. They can be used with DN 250 extraction connectors.

Adjustable ventilation inlets are located on both sides of the lower screen box. Therefore, hot used sand is passed through with air during the screening process.
This transports dust and hot air from the polygon screen and lowers the sand temperature.
The process can be reinforced by the supporting impellers and carrier scoops mentioned above.

An overview of all the advantages:

  • Free intake opening hinders blocking, even with green bales
  • Sprung, pre-tensioned screen areas enable breaking up sand lumps
  • A wide range of screen meshes is offered individually, tailored for all requirements
  • Advantageous stocking of spare parts as a result of identical outer dimensions for all replacement screens in a model series. Also in case of different meshes
  • Torsion-resistant screen body
  • Height saving due to lean outlets
  • Zinc-plated designs guarantee optimal corrosion protection
  • Trouble-free maintenance through easily accessible, similarly constructed pre-stressed screen areas.
  • The VHV belt conveyor outlet also enables the installation of the polygon screen at ground floor level or in basements.

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