DE10101313A1 - Foam filter insert pore size continually varied as required by turbidity sensor-regulated external pressure unit - Google Patents

Abstract

In a filtration process to separate solid, fluid or dissolved substances from a fluid, the substance is passed through one or more compressible filters. The filter can be especially subjected to a variable pressure by means of which the pore size is adapted in accordance with the substance to be separated and enhancing process efficacy The compressible filter material is polyurethane foam. Alternatively the filter material is made up of flakes from 0.1-50 mm preferably 5-15 mm in diameter. The fluid passes two or more times through the same filter or two filters arranged in series, and under increasing pressure. Also claimed is a suitable filter assembly (10) with a housing (12) with an inlet and outlet and a filter insert (44) which can be compressed or de-compressed with a suitable bellows assembly (18). One end of the bellows is fixed, and the other can move within the housing. Movement is effected by a piston (16) in a cylinder (14) in response to turbidity sensor (100) signals.

Description

The present invention relates to a filtration method and Filtration device for the separation of solid, liquid or dissolved substances from a fluid. The fluid is passed through a compressible filter, in which the substances to be separated separate out.

The filtration device described and the one described Filtration processes are often used to remove solid or liquid particles from Fluids, such as liquids (suspensions or emulsions) or gases (dusts or aerosols). Here are the different filtrations process, for example, differentiated according to the type of filter medium.

In depth filtration, to which the present invention relates in particular relates, the separation of the particles takes place in the depth of the respective for the Fluid permeable filter medium. The one to be distinguished from this Cake filtration is the filter medium during the filtration from the Good to be separated built up. Deep filtration is particularly suitable for the extraction of pure filtrates, while the cake filtration is usually used Substance extraction from suspensions is used.

Porous piles are often used as filters for deep filtration made of sand, gravel, half-burned Dolomites or anthracite. For  Treatment of water or the treatment of waste water is becoming more and more common also used polystyrene.

The particles are separated from the fluids during deep filtration, by removing the particles from the smaller pores or openings in the filter be retained or on the filter, for example in the flow Adsorb capillaries.

Numerous processes for deep-bed filtration are known in the prior art.

DE 26 47 261 describes a low-bed filter with two vertically one above the other arranged filter layers made of grains. The grains of the top layer are uniformly formed and consist of a synthetic material. The specific gravity of the grains of the lower layer is higher than that of the Grains of the upper layer. The filter is cleaned by backwashing. After backwashing, the filter layers arrange themselves again in such a way that Mix the filter layers only in the contact area of both Filter layers takes place.

GB 21 91 109 relates to a filter for cleaning water. The Filters can be made up of multiple layers that are reticulated Polyether polyurethanes exist.

U.S. Patent 4,303,533 describes a method of removing suspended Particles from liquids described. The liquids are at the described method by a filter with at least two layers open-cell, compressible and hydrophobic polymer materials. For Cleaning the filter compresses it.

DE 29 01 335 relates to a filtration process with which Allow hydrophobic liquids to be separated from water. The separation takes place  by means of polyurethane foam particles, which in the hydrophobic liquids hold back the foam. By squeezing the foam particles after the The hydrophobic liquids can be obtained by filtration.

In EP 0 608 441 B1 a filtration device for the separation is finer Solid particles described. The filter material consists of an accumulation fibrous lump that separates between a lower and an upper plate to eliminate unnecessary air spaces. To clean the filter material, the lower plate is removed so that the fibrous lumps can float freely in a cleaning bath.

DE 197 38 067 finally describes a device for filtering Liquids using a compressible filter medium made of fibrous Plastic balls. During filtering, the plastic balls are between two Perforated plates compressed. The perforated plates are used to clean the filter balls spread apart.

Common to the known methods that the difficult setting of the Ratio of the pore size of the filter material to the size of the material to be separated Particles must be made before filtration and often not optimal is hit. This is especially the case when fluids with a wide range Particle size spectrum must be filtered or the amount and the Composition of the substances to be separated in the fluids strong temporal Are subject to fluctuations, for example in the purification of Sewage. Due to this not always optimal adaptation of the filter to the substances to be separated often lead to insufficient filtrate qualities. A insufficient adaptation of the filter to the substances to be separated regularly also leading to premature clogging of the filters, resulting in short Filter service life results. This increases the operating costs unnecessarily.  

The present invention was therefore based on the object, both a simple, effective and inexpensive filtration process as well simple, effective and inexpensive filtration device for the separation of to provide solid, liquid or dissolved substances from fluids.

This problem is solved by a filtration process for the separation of solid, liquid or dissolved substances from a fluid in which the fluid is passed through at least one compressible filter and the filter through Applying pressure is adapted to the substances to be separated and / or the effectiveness of the filter is hereby set and by a Filtration device for the separation of solid, liquid and dissolved substances from a fluid, which has at least one housing with inlet and outlet, in which is at least one compressible surrounded by a flexible material Filter is provided, which with the help of at least one device can be compressed or decompressed.

The method according to the invention has the advantage that it is quick in time changing concentrations and compositions of solid, liquid or Solutes in the fluid respond quickly with an adjustment of the filter and the filter can thus be optimally adapted to the substances to be separated can be adjusted. This is especially true for fluids that need to be separated Have particles whose particle sizes vary greatly over time. Through the Different pressures can be applied to the filter Pore sizes in the filter are adapted to the changing particle sizes. This can lead to premature clogging of the filter with coarse particles can be prevented, making the filters out of service less often need to be cleaned. The filter service life can be determined with the help of the present Invention thus be increased. The present invention thus adjusts inexpensive filtration process ready. In addition, the present invention, the filter effectiveness and thus desired Degrees of depletion in the fluid to be purified.  

The term fluids includes both liquids and gases.

With the method according to the invention, finely divided substances can be made from fluids (collectively referred to as so-called dispersions). It can Solid particles from liquids (so-called suspensions) or solid particles Gases (so-called dusts) are separated. With the help of the invention Processes can also be made from liquid substances that are in the form of drops Liquids (so-called emulsions) or gases (so-called aerosols) are removed. It can be separated from liquids as fluids also liquid substances that form a mixture gap with the liquid. examples for this are hydrophobic liquids in water as a fluid. With the help of the present Invention can also be detachable or dissolved substances, for example Water constituents, such as salts and their ions, such as metal salt ions, for example heavy metal ions, separated from liquids as fluids become.

In the context of the present invention, solid particles with particle sizes down to colloidal dimensions (<10 ⁵ cm), which are undissolved in the fluid, are preferably separated from fluids.

With the help of the present invention, solutes or dispersed Substances with a particle size of ionic radii (approx. 100 µm) up to the mm Area are separated from fluids. Substances can be particularly advantageous are separated, the particle size of preferably about 1 micron to 1000 microns, more preferably from about 1 µm to 100 µm, particularly preferably from 1 µm to 50 µm.

Within the scope of the present invention, any, the expert known, compressible filters are used. These can, for example, in Form of filter mats or filter piles. The filters point  preferably a porous structure. They also become elastic Filter materials preferred.

The use of a compressible filter has proven to be particularly advantageous foamed filter material exposed. Foamed filter materials can have a high adsorption capacity. You can use large surfaces Make available. In addition, there is a wide range in foamed materials Size range of pores capable of adsorption. Open cell foams are preferred.

In the context of the present invention, natively foamed materials, d. H. naturally occurring foams, find use. Preferably are artificially generated, d. H. synthetic foams used. You can organic polymer materials. Elastic, organic are preferred Polymers. In the context of the present invention, foams are made Plastics particularly preferred.

According to the invention, foams are preferably used that have a Density from 10 to 1000 g / l, preferably from 20 to 900 g / l and especially preferably have from 40 to 60 g / l.

In the context of the present invention, foams can be used that with the help of chemical blowing agents. These point preferably density of more than 200 g / l. Example of this is Polyvinyl chloride (PVC).  

Furthermore, thermoplastic foams can be used, which with physical blowing agents are produced. These preferably point Densities from 10 g / l to 500 g / l. These foams can be foamed by extrusion of the gas-laden melt (XPS) or by expansion, where the polymer particles are pre-foamed and later welded into a molded part be (EPS, EPP). Examples of such foams are polystyrene and Polypropylene (EPP).

Furthermore, special foams can be used in which the foam is produced by blowing in air, such as, for example, the copolymers styrene and butadiene. Other special foams are foams that are produced by condensation and segregation in the liquid phase. Examples include spinodal segregation or the so-called sol-gel process, for example SiO ₂ “airgel” with a density of up to 30 g / l or organic “aerogels” such as polystyrene / cyclohexane.

Reaction foams can also be used in the context of the present invention be used. These can be, for example, melamine-formaldehyde resins, which are preferably made using physical blowing agents become. Rigid or soft foams of the polyurethane are particularly preferred used using chemical and / or physical blowing agents can be produced.

There are polyurethane foams based on polyetherols and aromatic isocyanates preferred. The production of Polyurethane foams are made using generally known methods, for example, by reacting isocyanates with isocyanates reactive compounds in the presence of optionally catalysts, Blowing agents, additives and / or auxiliaries. The raw materials for the  Production of the polyurethane foams which can be used according to the invention described below as an example.

As isocyanates, the known aliphatic, cycloaliphatic, araliphatic and preferably aromatic organic isocyanates, preferably polyfunctional, particularly preferably diisocyanates become.

Examples include: alkylene diisocyanates with 4 to 12 Carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyl tetramethylene-diisocyanate-1,4, 2-methyl-pentamethylene-diisocyanate-1,5, tetra methylene diisocyanate 1,4 and preferably hexamethylene diisocyanate 1,6; cycloaliphatic diisocyanates, such as cyclohexane-1,3- and -1,4-diisocyanate as well any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl 5-isocyanatomethyl-cyclohexane (isophorone diisocyanate), 2,4- and 2,6- Hexahydrotoluylene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the corresponding Isomeric mixtures, aromatic di- and polyisocyanates, such as. B. 2,4- and 2,6- Toluene diisocyanate (TDI) and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) and the corresponding Mixtures of isomers, naphthalene-1,5-diisocyanate (NDI), mixtures of 4,4'- and 2,4'-diphenylmethane diisocyanates, mixtures of NDI and 4,4'- and / or 2,4'-diphenylmethane diisocyanates, 3,3'-dimethyl-4,4'-diisocyanatodiphenyl (TODI), mixtures of TODI and 4,4'- and / or 2,4'-diphenylmethane diisocyanates, polyphenyl polymethylene polyisocyanates, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (raw MDI) and mixtures of raw MDI and toluene diisocyanates. The organic di- and polyisocyanates can be used individually or in Form of their mixtures are used.

So-called modified polyvalent isocyanates, ie. H. Products by chemical conversion of organic di- and / or  Polyisocyanates obtained are used. Examples include ester Urea, biuret, allophanate, carbodiimide, isocyanurate, uretdione and / or Di- and / or polyisocyanates containing urethane groups. Come in detail for example into consideration: organic, preferably containing urethane groups aromatic polyisocyanates with NCO contents of 33.6 to 15% by weight, preferably from 31 to 21% by weight, based on the total weight, modified 4,4'-diphenylmethane diisocyanate, modified 4,4'- and 2,4'- Diphenylmethane diisocyanate mixtures, modified NDI, modified TODI, modified crude MDI and / or 2,4- or 2,6-tolylene diisocyanate, where as Di- or polyoxyalkylene glycols, which are used individually or as mixtures can be mentioned, for example: diethylene glycol, dipropylene glycol, Polyoxyethylene, polyoxypropylene and polyoxypropylene polyoxyethylene glycols, triols and / or tetrols. NCO groups are also suitable Prepolymers with NCO contents of 25 to 3.5 wt .-%, preferably from 21 to 14% by weight, based on the total weight, made from, for example Polyester and / or preferably polyether polyols and 4,4'-diphenylmethane diisocyanate, mixtures of 2,4'- and 4,4'-diphenylmethane diisocyanate, NDI, TODI, mixtures of NDI and isomers of MDI, 2,4- and / or 2,6-tolylene diisocyanates or raw MDI. Liquid, Polyisocyanates containing carbodiimide groups and / or isocyanurate rings NCO contents of 33.6 to 15, preferably 31 to 21 wt .-%, based on the Total weight, e.g. B. based on 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate, NDI, TODI and / or 2,4- and / or 2,6-tolylene diisocyanate.

The modified polyisocyanates can be used together or with unmodified ones organic polyisocyanates such. B. 2,4'-, 4,4'-diphenylmethane diisocyanate, NDI, TODI, crude MDI, 2,4- and / or 2,6-tolylene diisocyanate if necessary be mixed.

As isocyanate-reactive compounds with usually at least two reactive hydrogen atoms, usually hydroxyl and / or Amino groups are expediently those with a functionality of 2  to 8, preferably 2 to 6, and a molecular weight of usually 60 up to 10,000. Have proven themselves. B. polyether polyamines and / or preferably polyols selected from the group of polyether polyols, polyesters polyols, polythioether polyols, polyester amides, hydroxyl-containing poly acetal and hydroxyl-containing aliphatic polycarbonates or Mixtures of at least two of the polyols mentioned. Preferably Polyester polyols and / or polyether polyols are used, the following known methods can be produced.

The polyester polyols preferably have a functionality of 2 to 4, in particular 2 to 3, and a molecular weight of usually 500 to 3000, preferably 1200 to 3000 and especially 1800 to 2500.

The polyether polyols have a functionality of preferably 2 to 6 and usually molecular weights from 500 to 8000.

For example, polymer-modified polyols are also suitable as polyether polyols Polyether polyols, preferably graft polyether polyols, especially those Styrene and / or acrylonitrile base, which is obtained by in situ polymerization of acrylonitrile, Styrene or preferably mixtures of styrene and acrylonitrile can be.

Like the polyester polyols, the polyether polyols can be used individually or in Form of mixtures can be used. They can also use the graft polyether polyols or polyester polyols and those containing hydroxyl groups Polyesteramides, polyacetals and / or polycarbonates are mixed.

The polyol components used for rigid polyurethane foams are: may have isocyanurate structures, in particular highly functional polyols, especially based on polyether polyols highly functional alcohols, sugar alcohols and / or saccharides as Starter molecules, for flexible foams, especially 2- and / or 3-functional ones Polyether and / or polyester polyols based on glycerin and / or  Trimethylolpropane and / or glycols as starter molecules or to be esterified Alcohols used. The production of the polyether polyols follows a known technology. Suitable alkylene oxides for the preparation of the Examples of polyols are tetrahydrofuran, 1,3-propylene oxide, 1,2- and 2,3- Butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene oxides can be used individually, alternately in succession or as mixtures be used. Alkylene oxides are preferably used which are primary Lead hydroxyl groups in the polyol. Polyols are particularly preferred those used to complete the alkoxylation with ethylene oxide were alkoxylated and thus have primary hydroxyl groups. For Production of thermoplastic polyurethanes is preferred Polyols with a functionality of 2 to 2.2 and no crosslinking agents.

Furthermore, as compounds which are reactive toward isocyanates Chain extenders and / or crosslinking agents are used. For example, to modify the mechanical properties of these Substances produced polyisocyanate polyadducts, e.g. B. the hardness, can the addition of chain extenders, crosslinking agents or if appropriate, mixtures thereof also prove to be advantageous. As Chain extenders and / or crosslinking agents can be water, diols and / or Triols with molecular weights from 60 to <500, preferably from 60 to 300 be used. For example, aliphatic, cycloaliphatic and / or araliphatic diols with 2 to 14, preferably 4 to 10 carbon atoms, e.g. B. ethylene glycol, 1,3-propanediol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and bis (2-hydroxyethyl) - hydroquinone, triols such as 1,2,4-, 1,3,5-trihydroxycyclohexane, glycerin and Trimethylolpropane and low molecular weight hydroxyl groups Polyalkylene oxides based on ethylene and / or 1,2-propylene oxide and diols and / or triplets as starter molecules.  

If chain extenders are used to manufacture the polyurethane foams, Crosslinking agents or mixtures thereof are used, these come expediently in an amount of 0 to 20% by weight, preferably 2 to 8 wt .-%, based on the weight of the reactive towards the isocyanates Compounds are used, thermoplastic polyurethanes preferably without Crosslinking agents are produced.

Compounds which are generally customary are suitable as catalysts, for example organic amines, for example triethylamine, triethylene diamine, Tributylamine, dimethylbenzylamine, N, N, N ', N'-tetramethylethylene diamine, N, N, N ', N'-tetramethyl-butanediamine, N, N, N', N'-tetramethyl-hexane-1,6-diamine, Dimethylcyclohexylamine, pentamethyldipropylenetriamine, pentamethyldiethylene triamine, 3-methyl-6-dimethylamino-3-azapentol, dimethylaminopropylamine, 1,3- Bisdimethylaminobutane, bis (2-dimethylaminoethyl) ether, N-ethylmorpholine, N-methylmorpholine, N-cyclohexylmorpholine, 2-dimethylamino-ethoxyethanol, Dimethylethanolamine, tetramethylhexamethylene diamine, dimethylamino-N methylethanolamine, N-methylimidazole, N- (3-aminopropyl) imidazole, N- (3- Aminopropyl) -2-methylimidazole, 1- (2-hydroxyethyl) imidazole, N-formyl-N, N'- dimethylbutylene diamine, N-dimethylaminoethylmorpholine, 3,3'-bis-dimethyl amino-di-n-propylamine and / or 2,2'-dipiparazine diisopropyl ether, dimethylpi parazin, N, N'-bis (3-aminopropyl) ethylenediamine and / or tris- (N, N- dimethylaminopropyl) -s-hexahydrotriazine, or containing mixtures at least two of the amines mentioned, including higher molecular weight tertiary Amines, as described for example in DE-A 28 12 256, are possible. Furthermore, organic catalysts which are customary for this purpose can be used Metal compounds are used, preferably organic tin compound dung, such as tin (II) salts of organic carboxylic acids, e.g. B. tin (II) acetate, Tin (II) octoate, tin (II) ethylhexoate and tin (II) laurate and the dialkyltin (IV) salts of organic carboxylic acids, e.g. B. dibutyltin diacetate, Dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate. Prefers  can tertiary aliphatic and / or cycloaliphatic amines in the mixtures be contained in the mixtures, particularly preferably triethylenediamine.

As blowing agents, optionally, preferably for the production of foamed polyurethanes, well-known blowing agents, such as. B. substances that have a boiling point under normal pressure in the range from -40 ° C to 120 ° C, Gases and / or solid blowing agents and / or water are used in customary amounts are, for example carbon dioxide, alkanes and or cycloalkanes such as for example isobutane, propane, n- or iso-butane, n-pentane and cyclopentane, Ethers such as, for example, diethyl ether, methyl isobutyl ether and dimethyl ether, Nitrogen, oxygen, helium, argon, nitrous oxide, halogenated hydrocarbons and / or partially halogenated hydrocarbons such as trifluoromethane, Monochlorotrifluoroethane, difluoroethane, pentafluoroethane, tetrafluoroethane or Mixtures containing at least two of the blowing agents mentioned by way of example contain.

Examples of auxiliaries and / or additives are surface-active ones Substances, foam stabilizers, cell regulators, fillers, dyes, pigments, Flame retardants, hydrolysis protection agents, fungistatic and bacteriostatic acting substances called.

Usually the organic polyisocyanates and the opposite Isocyanate-reactive compounds with a molecular weight of 60 to 10000 g / mol implemented in such amounts that the Equivalence ratio of NCO groups of the polyisocyanates to the sum of reactive hydrogen atoms of the compounds reactive towards isocyanates 0.5 to 5: 1, preferably 0.9 to 3: 1 and in particular 0.95 to 2: 1. It may be advantageous if at least the polyurethanes partially contain bound isocyanurate groups. In these cases, a Ratio of NCO groups of the polyisocyanates to the sum of the reactive ones  Hydrogen atoms of 1.5 to 60: 1, preferably 1.5 to 8: 1 are preferably chosen become.

In a further, advantageous embodiment of the present invention the filter in the form of flakes. The filter flakes preferably have a Flake size from 0.1 to 100 mm, more preferably from 5 to 50 mm and particularly preferably from 5 to 15 mm. The flakes are preferred anisodimensionally constructed. This allows the room to be optimally filled Filter volume can be reached. The permeability of the fluid through a pile of flakes of anisodimensional shape is less than that of a bed spherical filter material. This is beneficial for the removal of Suspensate from fluids. There are advantages for the present invention for filter flakes, which have a sieving capacity of 0.1 to 100 mm, are further preferred from 5 to 50 mm and particularly preferably from 5 to 15 mm. The Sieving ability is determined with standardized sieves.

The filter can have functional groups for certain applications, for example for the separation of dissolved or undissolved water constituents, such as Ions, salts, heavy metals or surfactants. Here are some examples: anionic groups such as carboxyl groups, sulfonic acid and sulfur-containing organic anionic groups, phosphonic and phosphorus-containing anionic Groups, structures bearing ammonium groups (secondary, tertiary or preferably quaternary ammonium groups), hydrophobic groups such as for example paraffin groups, aromatic groups.

In the context of the present invention, filters with a Filter layer thickness without pressure from 10 mm to 2 m, further preferably from 10 to 100 cm and particularly preferably from 10 to 50 cm, used.  

In the context of the present invention, the compressible filter can also be made of a combination of different filter materials, for example in Sandwich construction can be combined.

By applying pressure to the compressible filter, this is in the Usually compressed. Filter properties such as pore size, filter resistance, the adsorbability and permeability of the fluid can be adjusted to the substance or substances to be separated in a defined manner by applying a certain pressure to the filter become. Also the filter effectiveness or the degree of depletion substance to be separated in the fluid can hereby be defined. In preferred embodiments of the present invention, the fluid at least twice through the same filter or through at least two filters that in series, d. H. are cascaded, passed, the pressures, with which the filter or filters apply in the course of the filtration process be varied. Advantages of these embodiments are that fluids in be effectively cleaned of solid, liquid or dissolved substances can, in which the substances to be separated a wide Have particle size distribution. There are particles in every filter pass different sizes can be filtered off by using the filter (s) different pressures is / are applied. An embodiment in which varies the fluid several times through the same filter Pressurization also has the advantage of low apparatus expenditure. If the fluid is passed through a cascade of filters, different filter materials can be used for the individual filters. In addition, the filters can be sorted independently from each other particle size-dependent downtimes decommissioned and cleaned become.  

Preferably, the pressures with which the filter or filters be increased in the course of the filtration process. Advantage of this The procedure is that first coarse substances, for example dispersed Solid particles with large particle diameters, and in the course of Filtration process always finer substances, for example dispersed Solid particles with small particle diameters can be separated. Filtration processes according to the prior art often occur Blockage of fine-pored filters due to coarse particles, which can cause need to be cleaned for a short period of time. This can be done with the present Invention through the optimal adaptation of the filter to the substances to be separated be avoided.

In a particularly preferred embodiment of the present invention are two or more individual filters cascaded, d. H. connected in series arranged, the pressures acting on the individual filters from the first to the last filter can be increased.

In the present invention, the fluid is preferably passed upstream passed the filter. The advantage here is that the filter easily after filtration the substances that can be cleaned during filtration in the filter have deposited. The filter can be cleaned in a clean Fluid flow in the downstream is passed through the filter. Due to the The weight of the separated substances can make cleaning easier.

In the context of the present invention, the pressure on the filter is preferably set such that the fluid mechanical resistance of the filter, which corresponds to the difference in the fluid pressures measured immediately before and after the filter, is between 10 ² to 10 ⁴ Pa.

To optimize the filtration process, the volume flow of fluid, which is passed through the filter can be defined. By  Varying the volume flow can directly affect the filtrate quality become. As a rule, a reduction in the volume flow of fluid improves the separation of the solid, liquid or solutes from the fluid, whereby the filtrate quality increases.

The passage of the fluid through the filter is due to external forces. For example, forces generated by pressure come into question, by negative pressure generated forces (vacuum) and hydrostatic forces (gravity).

The present invention can be used for the treatment of water for drinking and cooling water, for cleaning beverages, liquid fuels, as well as pharmaceutical products, for the separation of dust from air and gases, for Cleaning and removal of disruptive components from aqueous Suspensions before ion exchange and membrane processes, for processing of organic substances contaminated with solid, liquid or dissolved substances Solvents, hydraulic oils or transformer oils.

The device according to the invention serves for the separation of solid, liquid or solutes from a fluid, for example for the filtration of Service water and waste water of various origins can be used. So circulated water can be treated as well as water in which due to legal regulations, a pollutant reduction is required. The area of application of the device is therefore very broad and can be both be equally interesting for industry and municipalities. Areas of application in this context are preferably textile laundries, Vehicle washing systems, cooling water circuits and sewage treatment plants.

According to the invention, the present filtration device has at least one Housing with inlet and outlet on, in which at least one of a flexible Material surrounded, compressible filter is provided, which with the help at least one device can be compressed or decompressed.  

Possible housing materials are stainless steel, such as V2A, steel as well as plastic. Preferred materials for inlet and outlet are Plastic or steel connections provided. The connection sizes for feed and The process is based on conventional pipe connection dimensions, which can be standardized according to DIN, for example.

According to the invention, the material surrounding the filter is a bellows, which one end connected to the housing and one end movable in the housing having. Material and size of the bellows can be according to the Requirements vary. The material should match the fluid being filtered have a corresponding tightness.

According to the invention, the bellows has both on its with the housing connected as well as at the movable end in the housing at least one Plate for applying pressure, at least one clamping ring and at least one Piston ring on. The clamping ring is used to attach the bellows to the Plate for applying pressure and the piston ring. The piston rings have that Task with a preferably cylindrical housing to seal the Bellows area compared to that for a device for compression or Decompression provided area.

The at least one device for compressing or decompressing the The filter of the present invention preferably has a cylinder with a piston on. In the present invention, a double is particularly preferred Acting piston cylinder made of stainless steel (V2A) with variable pressure and Stroke length for use. This is controlled with compressed air, the Compressed air through a compressor with a corresponding pressure control valve is made. The pressure control valve has a working range from 0 to 10 bar. Alternatively, the piston cylinder can also be controlled hydraulically.  

According to the invention, the piston of the at least one device for Compression or decompression of the filter with the plate for applying Pressure of the end of the bellows movable in the housing via a pressure rod connected. The contact pressure on the filter material can thus by applying Compressed air on the cylinder can be changed continuously, the filter fineness changes in parallel.

Furthermore, the device according to the invention has in both ends of the Bellows openings, the end of which is connected to the housing Bellows provided opening with the drain provided in the housing is connected and the opening which is in the movable end of the housing Bellows is provided with the inlet provided in the housing through a flexible connecting element is connected. With this flexible The connecting element is preferably a hose or a Telescopic tube. The flexible connector is required to both depressurized position as well as in the compressed position of the filtration device to ensure an inflow or outflow of the fluid to be filtered.

The transport of the fluid to be filtered is carried out through suitable pipelines ensures which are connected to the inlet and outlet. In the Pipelines are provided at least one valve, whereby it is is preferably a solenoid valve.

The device according to the invention also has at least one sensor and at least one control / regulation, which both sensors and Controls and regulates valves and pressure regulators. The also preferably in the Pipes provided sensors are preferred for measuring the Turbidity and used for a measurement of the flow. With the help of this Additional modules such as B. turbidity and flow measurement and Adding devices for treatment chemicals can automate the process device according to the invention.  

The fluid is supplied with a pressure pump, whereby it does not matter plays which connection is used for the inlet or outlet. So one has to specific filterability can be determined on the basis of experiments in the laboratory and put into practice taking into account the maximum throughput become. The amount of filter depends on the pressure of the feed pump, the Contact pressure of the cylinder, the filter material, the filter surface, the fill level of the Filter material and the filterability of the fluid. The bellows filled with different filter materials, the filter size vary and thus the amount of fluid can be adjusted.

During the filtration, the unfiltered, so-called raw water flows through it Filter module, whereby the pollutants get caught in the filter and get there fix. The filtrate is discharged from the filtration device or one Fed reuse. It turns out that better water quality must be reached, the filter module can with increasing the air pressure be compressed more, whereby the microfine pores of the filter material narrowing even more so that better water quality is achieved. The filtered pollutants get stuck in the filter, concentrate on and reduce throughput. Is the specified minimum quantity falls below, there is a backwash cycle. The cylinder vents and constantly moves back and forth between depressurized and compressed position.

In addition, the water supply changes, so that the inlet to the outlet and the Expiration to the inflow becomes. This is done by means of existing in the piping Solenoid valves and the intended control / regulation carried out. The stored pollutants are removed in this way and in a separate one Container directed. At the end of the backwash cycle Filtration position resumed and the normal filtration process restores yourself again.  

The present application is further intended to be based on the following examples 1 to 9 are explained in more detail.

example 1

Example 1 relates to the purification of wastewater from a white laundry Purpose of reuse.

The proportion of anionic surfactants was removed in collective waste water from a white laundry Charge titration with the PCD from Mütek determined. The Charge neutralization in the wastewater was carried out by dosing the titrimetrically determined equivalent of cationic polyelectolyte z. B. Cytec Superfloc C-591 (poly (DADMAC) from 0.1 percent solution with stirring a 200 rpm propeller stirrer over 15 minutes. It came into being a stable suspension of very fine particles. This suspension was once through a compressible filter made of polyurethane (PUR) foam with a Flock size of about 8 mm passed. The filter layer had a thickness without Pressurization of 6 cm. The filter was pressurized to 500 Pa acted upon. The pressure was applied by placing Weights on a plate-shaped stamp. The volume flow of suspension, passed through the filter was 35 ml / min. The results of the Filtration is shown in Table 1 below.

Table 1

Results of wastewater treatment in a white laundry

The colorless water obtained from the filtration, which is practically free of turbidity could be used again as rinse water.

Example 2

Example 2 relates to the removal of a dye from a wastewater Multiple passage of a filter with constant pressure on the filter.

The disperse dye, for example, is used to dye synthetic fibers Palanil Dark Blue used. From dyeing sewage and used The dye must be separated from liquors. This was achieved by filtering the Wastewater according to the present invention, wherein the dye in the used filters farewell.

Waste water with 0.01 g / l Palanil Dark Blue was filtered out several times PUR foam flakes with a flake size of about 8 mm passed. there the wastewater was decolorized. The filter layer had a thickness without Pressurization of 6 cm. The filter was with a constant Pressure of 600 Pa applied. The pressure was applied by Place a weight on a plate-shaped stamp. The following table 2 shows the photometrically determined reductions in the concentration of Dye in the waste water.

Table 2

Depletion of Palanil from waste water

As the number of filter passages increased, the proportion of dye in the Water and transparency improved.

Example 3

Example 3 relates to the separation of a dissolved dye from a Waste water under multiple passage of a filter when the filter is loaded with a constant pressure that varied from test series to test series.

The wastewater from a dyeing plant where dyeing is done with methylene blue has been several times through a filter made of PUR foam with a flake size of about 8 mm and a filter layer thickness of 6 cm without pressure and discolored. The following table 3 documents the effectiveness of the Separation of the methylene blue from the wastewater depending on the Applying pressure to the filter. The initial concentration Methylene blue in the wastewater was 0.001 g / l. The volume flow Waste water passed through the filter was 30 ml minute. The Pressure was applied by placing weights on one plate-shaped stamp. The concentration of the dye was determined photometric at 660 nm using a previously created calibration curve.  

Table 3

Methylene blue fixation on PUR foam depending on the pressurization of the filter (measured values in% bound dye)

With the selected volume flow and the selected flake size, this results an optimum separation at a pressure of 882 Pa after 3 hours Filtration.

Example 4

Example 4 relates to the separation of a dissolved dye from a Waste water under multiple passage of a filter with increasing Pressurization of the filter.

Samples of the wastewater described in Example 3 were each at one hour different pressurization of the filter with a constant Volume flow of 30ml / min. passed through the filter according to Example 3. there  was the wastewater through the filter 6 times in each pressure stage headed. The pressure was applied by applying weights a plate-shaped stamp. The determination of the concentration of the dye was carried out photometrically at 660 nm using a previously created Calibration curve.

Table 4

Methylene blue fixation on PUR foam

As part of the investigation of dye separation depending on the The filter is pressurized with a filtration time of 1 Hour an optimum separation at 225 Pa.

Example 5

Example 5 relates to the removal of an anionic copper complex a filter made of PEI-modified polyurethane (PUR) with multiple passages of the filter.  

The filter consisted of a 5.8 g heavy PEI (polyethyleneimine) modified polyurethane foam with a sieve of 8 mm. The filter layer had a thickness of 3 cm without the application of pressure. The filter was pressurized to 708 Pa. The pressure was applied by placing weights on a plate-shaped stamp. 100 ml of a 10 ^-3 mol solution of a copper hexatartrato complex (pH 2.5) were passed through this filter in a cycle. Cu ^{2+ was} determined in the filtrate using ICP-OES.

Table 5

Bound copper [mg] based on the mass of the PEI modified polyurethane foam filter [g]

The result demonstrates the separation of the anionic copper complex on the with PEI modified polyurethane foam.

Example 6

Example 6 relates to the removal of a dye from wastewater With the help of foamed PUR filters of different flake sizes.  

From a wastewater that corresponds to the wastewater presented in Example 2, Palanil was separated on PUR foam of different flake sizes. The Filter layer thickness was 6 cm without pressurizing the filter. The for the The filtration pressure selected for the filter is shown in Table 6. The pressurization was kept constant during the filtration and was done by placing weights on a plate-shaped stamp. The Volume flow of waste water was 30 ml / minute. The waste water was in the Circulation through the filters.

Table 6

Palanil separation on PUR foam of different flake sizes

Measured values:% separated Palanil after 30 minutes of filtration under Multiple passage of the respective filter

Under the selected conditions, the separation on a PUR foam is included a flake size of about 8 mm with a pressure of 233 Pa most effective.  

Example 7

Example 7 relates to the filtration of a wastewater that is suspended and contains dissolved ingredients.

A simulated waste water from 0.01 g Palanil and 0.001 g methylene blue per liter was through a filter made of PUR foam with a flake size of about 8 mm headed. The filter layer thickness was 6 cm without pressurizing the Filters. The volume flow of simulated waste water was 30 ml / minute. The Filtration was carried out at different pressures of the filter carried out. The pressure was applied by applying weights on a plate-shaped stamp.

The filtration was carried out in a cycle and was 3 hours. The The dye concentration was determined again using Calibration relationships.

Table 7

Amount of dye bound to the PUR foam filter [mg] after filtration based on the filter mass [kg]

In addition to the experiments with the simulated wastewater described above, with a pressurization of 3244 Pa also tests with waste water carried out, each containing only Palanil or methylene blue (see third last and penultimate row of Table 7). With a joint separation from Palanil and methylene blue produce a larger amount of methylene blue (53.3 mg / kg) than when the single separation of methylene blue (45.8 mg / kg) the Case is. The separation is influenced synergistically. The methylene blue can can be separated from the mixture of both dyes more effectively than Methylene blue alone.

Example 8

Example 8 relates to the removal of a dye from a waste water Help a cascade of filters.

The wastewater presented in Example 2 was through PUR foam filter with a flake size of 8 mm. The filter layer thickness was 6 cm without pressurizing the filter. There was a filter cascade with three Stages used. The filters were pressurized by placing them on of weights on a plate-shaped stamp. The volume flow Waste water was 34 ml / minute in each case. The sewage was once through the Filter cascade directed.  

Table 8

Palanil [mg] bound to the PUR foam filter after filtration based on the filter mass [kg]

With increasing number of cascade levels passed, the Dyestuff freight of wastewater.

Example 9

Example 9 relates to the separation of Palanil from a wastewater constant pressurization of the filter and variation of the volume flow Sewage.

Waste water according to Example 2 was used again for the experiments. The Waste water was passed through a filter according to Example 2. The volume flows the wastewater with which the filter was flown was varied. The filters were subjected to constant pressures in two test series. The Pressure was applied by placing weights on one plate-shaped stamp. The results of the tests are shown in Table 9 remove. The amount [g] of bound palanil was based on the Mass of the filter [kg] determined after each filter passage.  

Table 9a

Palanil bound to the filter [g] based on the filter mass [kg] when the filter was pressurized to 796 Pa

Table 9b

Palanil bound to the filter [g] based on the filter mass [kg] when the filter was pressurized to 3078 Pa

As expected, the best partitions were at the lowest Volume flow, d. H. the smallest throughput.  

The filtration device according to the invention is in the following on a Embodiment explained in more detail. It shows

Fig. 1 shows a cross-section of a filtration device in a compressed position filter with pipe connections and control / regulation;

Fig. 2 is a cross-section of a filtration device in unpressurized filter position; and

Fig. 3 shows a cross section of a filtration device in the compressed filter position.

As shown in FIG. 1, the filtration device 10 comprises a housing 12 in which both a pressure cylinder 14 with a piston rod 16 and a bellows 18 are provided, the bellows 18 having piston rings 20 , 22 , tension rings 24 , 26 at both ends and pressure plates 28 , 30 . The pressure plates 28 and 30 shown in turn to openings 32 and 34, wherein a connecting piece 36 is provided in the opening 32, which is preferably screwed into the opening 32 and is suitable for connection to a hose 38th In opening 34, a pipe fitting 40, which preferably represents the flow, is introduced, which is also preferably threaded through the housing 12 in the opening 34 of the pressure plate thirtieth

The hose 38 connects the connector 36 screwed into the opening 32 of the pressure plate 28 to the pipe connector 42 , which is preferably provided as an inlet. Due to its flexible material properties, the hose 38 enables a safe inlet and outlet when the filtration or backwashing is carried out both in the compressed ( FIG. 3) and in the unpressurized ( FIG. 2) position of the bellows 18 .

Depending on the application, the bellows 18 can be filled with different filter materials 44 , the filter size being reduced by compression and increased by decompression in order to adapt to varying amounts of water. The filter fineness can also be changed by compression and decompression of the filter material 44 , which enables adaptation to different water qualities.

The filter material 44 is compressed and decompressed via the piston rod 16 of the pressure cylinder 14 connected to the pressure plate 28 . The pressure cylinder 14 is operated with compressed air, a control valve 46 controlling the supply of compressed air into an upper chamber 48 for compression and into a lower chamber 50 for decompression. The two chambers 48 , 50 of the pressure cylinder 14 are connected to a pressure regulator 54 via connecting lines 52 via the control valve 46 . The compressed air provided by, for example, a compressor (not shown) is fed to the pressure regulator 54 via a compressed air inlet 56 .

The fluid to be filtered is supplied via a feed pump 58 , preferably a pressure pump. This is connected to inlet and outlet 40 , 42 via connecting lines 60 to 66 , preferably stationary pipes. Solenoid valves 70 to 76 for controlling the direction of flow of the fluid are arranged between the connecting lines 60 to 68 . Connecting line 68 additionally has a sensor 80 for measuring the turbidity of the filtrate and a sensor 82 for measuring the flow rate, which are each connected to a control / regulation 100 via electrical connecting lines 90 , 92 . The control / regulation 100 is also connected to the pressure regulator 54 and the solenoid valves 70 to 76 .

When filtering a fluid, the solenoid valves 72 and 74 are closed and the solenoid valves 70 and 76 are open. The fluid supplied by the feed pump 58 then flows through the connecting line 60 , the pipe connection piece 42 , the hose 38 , the connection piece 36 and the opening 32 into the filter material 44 . When flowing through the filter material 44 , the pollutants get stuck in the filter material 44 and settle there. The fluid that has passed through the entire filter material 44 , which is also referred to at this time as the filtrate, flows through the opening 34 , the pipe connection piece 40 , the connecting line 66 and 68 into the sensor 80 for measuring the turbidity and subsequently into the sensor 82 for measuring the Flow rate. If the measurements carried out by the control / regulation 100 result in values which exceed preset tolerance limits for turbidity and flow rate, the control / regulation 100 increases or decreases the value of the air pressure preset for the respective filtering, depending on the desired filter result, via the pressure regulator 54 . When the air pressure is increased, the filter material 44 is compressed to a greater extent, so that the pores of the filter material 44 narrow even more and thus a better filtrate quality is achieved.

If this increase in air pressure combined with greater compression of the filter material 44 does not lead to an improvement in the filtrate quality, the control / regulation 100 initiates a backwash cycle for rinsing the filter material 44 . The solenoid valves 70 and 76 are closed and the solenoid valves 72 and 74 are opened. This changes the fluid flow in such a way that the inlet becomes the outlet and the outlet becomes the inlet. The fluid thus now flows in the opposite direction through the filter material 44 , the pressure cylinder 14 being vented and constantly moving back and forth between the unpressurized ( FIG. 2) and the compressed ( FIG. 3) position. The pollutants stored in the filter material 44 are removed in this way and passed into a separate container (not shown). After the backwash cycle has ended, the solenoid valves 72 and 74 are closed again and the solenoid valves 70 and 76 are opened again, as a result of which the filtration position is restored and the normal filtration process is restored.

With the help of the control / regulation 100 as well as the sensors 80 , 82 and optionally additionally provided sensors and the solenoid valves 70 to 76 , a fluid can also be subjected to repeated filtration by the filtrate being fed through the connecting lines 66 , 62 and 60 to new filter runs.

In FIG. 2, the filtration device is shown in unpressurized position 10, which corresponds to the maximum filter size.

10 Fig. 3 shows the filtration device in a compressed position.

Claims (20)

1. Filtration process for the separation of solid, liquid or dissolved Substances from a fluid in which the fluid is passed through at least one compressible filter is passed and the filter by applying Pressure is adapted to the substances to be separated and / or the Effectiveness of the filter is hereby set. 2. The filtration method according to claim 1, wherein the compressible Filters made of foamed filter material, especially polyurethane foam, is. 3. Filtration method according to claim 1 or 2, wherein the filter in Form of flakes is present. 4. Filtration method according to claim 3, wherein the filter flakes a Flake size from 0.1 to 100 mm, in particular from 5 to 50 mm and further in particular from 5 to 15 mm. 5. Filtration method according to one of the preceding claims, in which the fluid passes through the same filter or through at least twice at least two filters arranged in series are passed, whereby the pressures with which the filter or filters during the Filtration process can be varied.   6. The filtration method according to claim 5, wherein the pressures with which the filter or filters are applied to in the course of the Filtration process can be increased. 7. Filtration method according to one of the preceding claims, in which the fluid is passed upstream through the filter. 8. Filtration method according to one of the preceding claims, in which the filter dissolved or functional groups to separate undissolved water constituents, such as ions, salts, heavy metals or Surfactants. 9. Filtration method according to one of the preceding claims, in which to optimize the filtration process the volume flow Fluid that is passed through the filter is set in a defined manner. 10. Filtration method according to one of the preceding claims, in which the pressure on the filter is adjusted so that the fluid mechanical resistance of the filter is between 10 ² to 10 ⁴ Pa. 11. Filtration device ( 10 ) for separating solid, liquid or dissolved substances from a fluid according to the filtration method according to one of claims 1 to 11, which has at least one housing ( 12 ) with inlet and outlet, in which at least one of Compressible filter ( 44 ) surrounded by flexible material is provided, which can be compressed or decompressed with the aid of at least one device. 12. The filtration device ( 10 ) according to claim 11, wherein the material surrounding the filter ( 44 ) is a bellows ( 18 ) which has an end connected to the housing ( 12 ) and an end movable in the housing ( 12 ). 13. Filtration device ( 10 ) according to claim 11 or 12, wherein the bellows ( 18 ) at both its connected to the housing ( 12 ) and in the housing ( 12 ) movable end at least one plate ( 28 ) for applying pressure , at least one clamping ring ( 24 , 26 ) and at least one piston ring ( 20 , 22 ). 14. Filtration device ( 10 ) according to any one of the preceding claims, wherein the at least one device for compressing or decompressing the filter ( 44 ) has a cylinder ( 14 ) with piston ( 16 ). 15. Filtration device ( 10 ) according to any one of the preceding claims, wherein the piston ( 16 ) of the at least one device for compressing or decompressing the filter ( 44 ) with the plate ( 28 ) for applying pressure to the end movable in the housing ( 12 ) of the bellows ( 18 ) is connected. 16. Filtration device ( 10 ) according to any one of the preceding claims, wherein the two ends of the bellows ( 18 ) have openings ( 32 , 34 ). 17. Filtration device (10) according to any one of the preceding claims, wherein the provided in connected with the housing (12) end of the bellows (18) opening (34) is connected to the provided in the housing (12) flow. 18. Filtration device ( 10 ) according to any one of the preceding claims, wherein the opening ( 32 ), which is provided in the housing ( 12 ) movable end of the bellows ( 18 ) with the inlet provided in the housing ( 12 ) by a flexible Connecting element ( 38 ) is connected. 19. Filtration device ( 10 ) according to one of the preceding claims, in which suitable pipes ( 60 , 62 , 64 , 66 , 68 ) are connected to the inlet and outlet in which at least one valve ( 70 , 72 , 74 , 76 ) is provided . 20. Filtration device ( 10 ) according to one of the preceding claims, which has at least one sensor ( 80 , 82 ) and at least one control / regulation ( 100 ).