Nauka i Tehnika (Aug 2016)
USAGE OF FILTERS FROM FIBROUS MATERIALS IN AMELIORATIVE AND HYDRO-TECHNICAL CONSTRUCTION
Abstract
Construction of first drainage tubular systems has been facing such problem as their protection against silting-up by soil particles penetrating through input openings. Searches and investigations have led to usage of various fibrous materials which are playing the role of filters. At the beginning glass-fibre mats have been widely applied for this purpose. However, the mats possessing good filtration properties have had a number of fundamental disadvantages. Works executed at the Institute of Mechanics of Metal Polymeric Systems (Gomel, Republic of Belarus) have played a big role in usage of plastic materials. A new technology has been developed with the purpose to obtain thermally-bonded fibres from thermoplastic material. The fibres have been called as polyethylene mats. Investigation of their properties has been carried out under load and it has revealed that their lateral and longitudinal permeability becomes equal at specified pressures, in other words the material takes an isotropic state. The considered interactions of filtrating material and skeleton frame have shown that the main water filtration occurs directly above perforation holes while the material above blind frame sections does not participate in the process. Due to this a new design of the filtrating element has been developed and it can be used in water intake systems for surface and underground water. The filtrating element consists of the skeleton frame with openings and a filtration covering which is installed on the frame. Water-feeding groove cavities are located on the skeleton frame and they are dispersing from perforation holes in the form of beams. These grooves can have side branches of the second, third and other orders. As beam-like arrangement of grooves creates the shortest flow paths for filtrated water from periphery to frame holes and area of groove cross section exceeds the area of poral holes in water in-take covering by a factor of hundreds, it is possible to ensure free water flow to openings. So such approach makes it possible to obtain high element productivity because practically the whole surface of the water in-take covering is involved in the process. Such filtrating elements can be used in various constructions for filtration of liquid and gas.
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