Russian scientists developed and patented a very effective and convenient filter. This filter purifies various types of petroleum products, solvents and oils from dirt particles and water drops. Designers claim most important feature of this filter to be gradually changing pore diameter, which can vary within wide range of predetermined parameters.

Filters are made of a special material – a polymer, based on polyvinyl formal, which molecules look like long chains, consisting of three types of links: acetate, vinyl-acetate and vinyl-alcohol. These names are not music to ears of those, who forgot school programme in chemistry, however, main point of this development is that ratio of these three components defines polymer properties. Varying abovementioned ratio, scientists developed synthesis technique for a polymer, which is good sorbing agent for water and doesn’t dissolve in organic liquids, for example, benzene, kerosene, and various kinds of oils.

Moreover, chemists learned to “sew” polymer macromolecules into three-dimensional networks, which “cells” change in diameter from microns to nanometers. This is the material which served as a basis for a filter cartridge with variable porosity. A cartridge can have desired shape, since you can make a blank of any configuration and then “sew” polymer molecules to fit requirements of certain problem. What is most important is gradual change of porosity, because until now filters were made of several parts with different porosity. That is why porosity changed abruptly on an interface, which resulted in sharp rise of hydraulic resistance and drop in filter capacity. Moreover, such filters were difficult to regenerate (wash from dirt). New filters haven’t shown any of mentioned problems.

Well, most popular shape of filter cartridge is thick tube, made of filtering material. Tube’s porosity gently grows towards to central axis. Pressurized liquid enters the tube and flows through pores in the filter, which has an open-porous structure, allowing liquids to penetrate polymer layers. The coarser particles are, the faster they get stuck in the filter. When scientists know something about a substance, which they want to filter, they choose appropriate pore size and total porosity for “caching” all dirt particles and water drops.

So, what shall we do to wash this filter? The process is easy – you add special SAAs (surface acting agents), which are Russian know-how, to water and dirt washes off a filter, which is reusable. Such filters can be used in many ways: their unique properties – high porosity, mechanical stability and chemical resistance; possible multiple regeneration; high filtration capacity and extremely low hydraulic resistance – define wide application fields for this development of Russian scientists. These filters are ideal for oil purification, as well as car, airplane and ship fuels, vegetable oil and various solvents. These filters work even with gases – they can be filtered and dehydrated by means of new generation of sorbing and filtering polymer substances, developed by Russian chemists.

Source: Russian Science News

Kizilova Anna