The feeding mixture of sand, gravel and water is fed by a suction dredger, compressed-air dredger, floating grab or a preparation plant to the bucket wheel. The solids are deposited in the bucket wheel tub and are excavated by the bucket wheel. The bucket wheel cups are equipped with special plastic screens of different gap widths. A natural vacuum is created through the extended suction chambers which reduces the dewatering degree to a minimum. In the tub a number of adjustable overflow weirs are located. Thus, it is possible to win finest sand or eliminate undesired fine sand.
Teeter bed separators make separations based on differences in settling velocities of the respective particles. A constant, homogeneous up-flow of water is established within the vessel, which will suspend or cause a certain size of low density particles to rise while higher density particles will sink. Size control and even distribution of feed particles are the keys to an efficiently operating Teeter Bed circuit.
Our air jig functions in a similar manner to our Baum Jig, except air is the fluid rather than water. There are great advantages to making separations with air, most notably the lack of process water to treat. There is no moisture penalty added to the product either. Air Jigs are most suitable for separations with discreet particles, and where a relatively large differences in density between the sink and float products exist. Air Jigs are environmentally friendly. In addition to the elimination of process water, dust emissions are practically zero by including a dust collector.
Jigs are best suited for separation of material with differences in relative density. Offering advantages based on low capital and operating costs, coupled with high unit capacity and high efficiency, Jigs are applied to a wide variety of feeds, including aggregates, coal and base minerals and recycled materials. Water jigs can be designed for any feed with a top size between 150 mm and 3 mm. Air jigs are more limited in the top size of feed that can be accepted, ranging from 60 mm to 3 mm.
SMT STICHWEH drag scrapers are products based on many years of experience and know-how. Hundreds of drag scrapers have proven themselves in the sand and gravel extraction.
Washing and classifying are the most important stages of the processing. Coarse-grained material is already cleaned during the screening. For fine-grained material like sand or grain mixtures special washing, dewatering and recovery systems are necessary. Especially for this the STICHWEH washing and dewatering bucket wheel was designed.
The simple and robust all-steel construction guarantees also under rugged conditions absolute operational safety. The pneumatic single-lever control of the scraper winch makes the operation simple and requires no previous knowledge. Drag scrapers are in terms of efficiency and reliability superior to other extracting methods and are especially suited for:
Dry and underwater extraction
River dredging and rescraping of not completely exploited flooded gravel pits