Screen and Aerator

Preparing sand means more than just cooling and mixing. To avoid a negative effect on the high quality of the sand, residual materials must be removed carefully. For this, magnetic separators, non-ferrous metal separators, sizers and polygonal screens are used.

Polygonal screens

Polygonal screen with inspection flap opened
Types of polygonal screens

Webac 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. 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.

Sand aerators for improving sand quality

To optimize sand properties, return sand and moulding sand aerators are used as appropriate. All systems are winners, because of their robust construction, low maintenance demands, and impressive performance.

The over-belt aerators and the vertical shaft aerators can be used with return sand in order to break up the lumps, minimizing the loss of sand. In the area of moulding sand, the slingers are used for fluffing and aerating the sand. This increases the smooth flow of the sand, and improves the forming properties. Depending on local conditions and requirements, various aerators types can be used.

Rising conveyor aerators

Installed rising conveyor aerator
Types of rising conveyor aerators

The over-belt sand aerator is fitted to a conveyor belt. The aerator wheel, which is positioned transversely to the direction of the belt, gathers the moulding sand from the belt, and throws it, parallel to the direction of the belt, into an expansion hood, where the sand trickles back on to the conveyor belt.

Vertical Shaft Aerators

WSK-120 vertical shaft aerators
Types of vertical shaft aerators

With the vertical shaft aerator, the entire flow of moulding sand is led from above to a horizontally working slinger wheel. The aerator housing has a large capacity, and is covered with an elastic rubber membrane. Loose hanging breaker pegs on the inside break up any lumps the sand may contain, slow the sand down, and aerate it. The sand then trickles into the aerator funnel.

Samum Aerator

Installed Samum Aerator
Samum Aerator types

The Samum Aerator makes the greatest demands on space, but also produces the best sand quality. Its basis is the central supply of sand to the double-walled slinger wheel. The return sand is accelerated at a high rotational speed, thrown against the conical breaker ring, and thereby aerated. The result is velvety, smooth-flowing, finished sand with outstanding properties.

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