Rotary Polygon Screens

Reliable. Robust. Easy to Maintain.

With the acquisition of Webac Gesellschaft für Maschinenbau GmbH, Simpson has been able to expand support for the foundry industry.

This includes the integration of the Webac W Series Polygonal Screen has been designed to provide continuous screening of foundry return sand in a green sand system. The polygonal screens are distinguished by their simple construction and reliable operation. The sieve body has six surfaces and is equipped with a dust-tight steel plate housing. It rotates around a drive shaft fitted with generously sized encapsulated ball bearings. The screens are made from high quality steel wire fixed to a hardwood frame and can be replaced quickly and easily. Foreign parts such as core residues over 12x12mm are separated via a subsequent separate outlet after the screening drum. Depending on the actual screen size, the housing is fitted with one or two large inspection flaps which are easily opened using gas pressure shock absorbers. The turning of the drum continually circulates the material for screening while it falls from one screen surface to another. Through screening and the related comminution and friction on the lumps in the sand, the loss from the sand cycle is kept to a minimum. In addition, the sand is fluffed up and aerated.


Project Information Worksheet

For separation of lumps, fugitive materials [tramp metal, core butts, filters, etc.] from the return sand.

Consisting of:

  • Base frame made of welded sectional steel construction with bearing blocks for mounting the shaft bearings, mounting block for the geared motor, geared motor connected with the screen by a flexible coupling.
  • Housing of the screen made of steel sheets, large inspection covers with safety lockings, gas filled shock absorbers for opening the inspection covers. Funnel for sand feedings, lump discharge chute, connecting flanges for the dust extraction..
  • Screen body with one-piece shaft including bearings, screen frames manufactured out of hardwood with be screwed in the screen body, screen cover made of steel cord mesh.

The polygonal screen has two inspection flaps due to the size shown, the smaller versions have only one.


Webac Gesellschaft für Maschinenbau mbH in Euskirchen, Germany together with its subsidiaries Webac Maskin AB in Stockholm, Sweden and Webac s.r.o. in Pribram, Czech Republic acquired by Simpson. Webac was originally a licensee of the Beardsley & Piper Speedmullor®. Since the acquisition, many technologies from Webac have been added to the Simpson product line and vice versa. The Simpson Speedmullor® is manufactured in Euskirchen and in the USA.