In separation of liquids and solutions industry, different methods and equipment are used for purification. The most practical and common of them is Filter Press. In this method, filter press is used for purification. This machine performs the purification process using filter cloth and plates. Technical information regarding the filter press machines and plates have been completely explained in other sections.
Considering wide extent of different solutions in term of acid and basic properties, grading, solid particle size, viscosity, temperature and also considering sensitivity to solution hygienic conditions, expected transparency range for the solution and solution volume, different types of filter press cloths are used. Filter press cloth selection is one of the key and important factors in optimizing any type of liquid filtration. The important points which must be considered in selecting filter press cloth are such as tensile resistance, easy filter cake release, resistance against abrasion and chemical reactions, heat properties, appropriate air permeability, easy transferring, particle retaining, etc.
Filter press cloths are produced of different types such as polyester, cotton, polyamide, polypropylene or combination of these types. Many important factors are considered in selecting the best filter press cloth which have so much effect on shelf life and durability of the cloth. These are as below:
Weight of the cloth (G/M2)
Air permeability of the cloth
Cloth tape design
Sealing of the latex edge
Material of the filter press cloth
Most important materials of filter cloth are Polypropylene (PP), Polyester and Polyamide (NAYLON). Safi Sazan Safa can supply a wide range of cloths according to customers’ special operations. But according to diversity and difference of the applications, cloth types are not limited to the following items:
Cotton cloths are used for rather high temperature and neutral and partly basic solutions. But because of having lint, this type of cloth can not be used where hygienic sensitivity is high; such as pharmaceutical applications. This cloth can be used in low pressures, up to about 5 Atmosphere according to the number of warp and weft per unit area (square inch) and weaving conditions. Hence, where high pressure is necessary because of different reasons such as viscosity, this type of cloth has limited application. Obvious property of this cloth is appropriate absorption and easy sealing during filtration. This type of cloth is of pure cotton or a combination of cotton, polyester and nylon and its properties are affected by properties of cotton and combined materials. This type of cloth has about 2-5 % shrinkage in warp and weft directions; hence, this property should be taken into consideration while sewing. Air-permeability of this cloth is medium and sometimes high and for this reason it is used for liquids with medium and big particles. Filtered liquid is not very transparent and passing small solid particles through the filter cloth is possible.
Polypropylene cloths are used for acid and basic and even neutral solutions. This type of filter cloth can easily resist temperature up to 110 Co and is used in a wide range of solutions and industries. This cloth has appropriate shelf life and in moisture and temperature is resistant and is not rotten. Also, for not having lint, has appropriate hygienic conditions and better washing capability and is recyclable. Its cake is also released easier.
This type of cloth before and after installing on filter plate, in term of size has high stability and its sizes are changed max. by 3%. This cloth has appropriate abrasion resistance and wide range of air-permeability. Unit air-permeability indicates amount of air passing through the cloth per area/time unit with difference of certain pressure 200 Pascal. This scale is different in other test methods.
Sealing conditions is more difficult for this type of cloth because of coarseness and stiffness of the warp and weft, hence it is not recommended for industries with so valuable solution. This cloth is produced with wide range of varieties.
Since this type of cloth is of polymer material is used for acid, basic and neutral solutions but against alkaline chemicals has less resistance. For having more thickness and soft material, has better sealing conditions and higher-pressure resistance. This filter press cloth is produced in one and double layers and its double layers can resist pressure up to 20 atmospheres.
Polyester filter press cloth has better heat-resistance of about 170 C and more suitable physical and abrasion resistance. Before and after installing on the plate, it has good dimension stability.
This type of filter cloth is used for different acid and basic environments and has softer structure and better sealing. It has more suitable physical and chemical resistance comparing to other types of cloths; but finished cost is higher comparing to other types.
Meanwhile considering different industrial conditions with efficient and variable use, cloth can be produced of combination of cotton, polyester and polypropylene with variable weaving types (mono-filament, multi filament and mono-multi filament).
This company is producing all types of filter cloth for solid and liquid filtration of Polyester, Polypropylene, Polyamide, with mono-filament fiber, multi-filament fiber and staple. Width of cloth produced by Finsa Industriales Company is from 140 cm to 300 cm.
Important properties of the cloths produced by this company are calendaring and heat-setting after producing by advanced weaving looms. By doing this (calendar and heat- set) surface of the cloths are completely smooth and cake formed on the plates are easily released by itself just after opening of the plates comparing with cloths which are not calendared and heat-set and the cake must be released manually by the machine operators. Obviously, this property causes significant saving in production process and reduces work force. Meanwhile, by heat-set and calendar, quality and shelf life of the cloths are increased so much and air-permeability range and thickness of the cloth are controlled.
By using Finsa Company cloths, production capacity can be increased and a product with better quality ca be produced. Considering this property and other merits, using this company products are completely economical.
Safi Sazan Safa Company as exclusive agent of Finsa in Iran for selling and distributing, is importing different types of filter cloths according to customers’ needs in different industries and supply sewed and ready to use filter after cutting by computerized laser-cut machine.
Industry is the production of goods and services in an economy. The main source of income of a group or company represents the relevant industry. If all economic activities that deal with the production of goods and services using man-made machinery and equipment.
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