Filter system for removing and / or neutralizing undissolved oils and greases on water-based emulsions

Abstract

Filter system for removing undissolved oils and greases from water-containing emulsions in containers and vats used for holding and storing emulsions used for cooling and lubricating workpieces and tools during machining, with at least - a tangential inlet (12) - into the emulsifier filter (1) - a subsequent injector for gas enrichment (28), - a downstream adhesion filter (2) with automatic vent (39) - an oil collection vessel (39d) with drain (39b) and - a subsequent capillary filter (3), wherein a skimmer (7) with a suction connection from below is provided for the extraction of the emulsion (5) and the oil / grease film (6) from the emulsion tray / emulsion container (4), wherein the filter system as a unit mechanically, physically and biologically treats the emulsion (5) with the insoluble oil / grease droplets (22) so that the oil / grease layer (6) is then removed from the filter system.

Description

[0001] The invention relates to a filter system for removing undissolved oils and fats from water-containing emulsions from containers and tubs used for storing and preserving emulsions.

[0002] Filter systems for removing undissolved oils and greases from water-based emulsions, particularly from containers and tanks used for storing emulsions, are available in a wide variety of designs. Surface belt skimmers are most commonly used for emulsion containers and tanks. These remove the floating oil / grease film. A mechanically / electrically driven endless belt is immersed in the tank or container, and its upward movement filters the oil / grease adhering to the belt from the surface of the emulsion. The oil / grease adheres to the belt, which is then deflected from its upward to a downward movement by a pulley and subsequently freed from the oil / grease film by a scraper. The oil / grease is collected in a container (bucket) via a horizontally sloping trough.The endless belt, cleaned in this way, then dips back into the tub or container, so that the adhering oil / grease is filtered out again from the surface of the emulsion by the downward and upward movement of the endless belt and via a second deflection roller.

[0003] In practice, a wide variety of machines for machining workpieces are known to use emulsions to cool and lubricate the workpieces and the tool. For example, in a computer-controlled lathe / milling machine, various lubricants and lubricating agents are used to reduce friction and ensure smooth sliding of the moving tool and workpiece holders. These prevent increased force from being required during movement and thus prevent seizing and subsequent machine failure.

[0004] Such lubricants are well-known in practice. They are referred to as slideway oils and usually consist of paraffin and naphthenic hydrocarbons with additives (e.g., manufacturer Scharr, trade name: Slideway Oil CGLP ISO-VG (68) and (220)). These lubricants are continuously metered between the guide rails of the tool and workpiece holders during operation, forming a thin film and thus ensuring smooth sliding. However, the movement of the guide rails forces the slideway oil out at the edges of the rails, requiring replenishment. For machining the workpieces with tools, the emulsion is pumped from the container or tray by a suction-pressure pump and sprayed onto the machining area via a nozzle for cooling and lubrication. The cooling and lubricating fluid, an emulsion, e.g.,The emulsion consists of a mixture of mineral oil, emulsifiers, stabilizers, and inhibitors (manufacturer Blaser, trade name: BLASOCUT® BC 25 MD) mixed with 90-98% water and 2-10% Blaser mineral oil mixture. As the emulsion flows from the workpiece and tool, the slideway oil is washed away from the edges of the guide rails and collected in the machine pan and / or container, where it accumulates on the surface of the emulsion as an oil-grease film. Furthermore, machining operations such as turning, milling, or drilling of the workpiece generate numerous metal chips, which are washed into the pan or container along with the emulsion and slideway oil. These metal chips are collected and removed from the machine manually or automatically. The pan or container is usually divided into different zones where the chips and emulsion are separated.Perforated screens are typically used here to ensure that the pump does not draw in chips to convey the emulsion and thus impede its delivery capacity. A disadvantage of this method is that the slideway oil obstructs the flow of the emulsion, so that with high emulsion circulation, a level gradient develops in the tray or container. This leads to overflow before the screen and also to insufficient emulsion flow to the pump.

[0005] A major problem arises from surface wetting caused by a film of bed oil, which prevents oxygen exchange into the emulsion and, especially during periods of inactivity, leads to increased bacterial and fungal growth, resulting in strong odors and discoloration of the emulsion. Particularly on weekends or during holidays, when the emulsion remains stationary for extended periods and temperatures exceed 30°C, a health hazard for operating personnel and the environment cannot be ruled out. Further problems arise from fungal filaments and slime bacteria, which frequently cause blockages in pipes and filters.

[0006] To avoid this, the machine, including the tank and / or container, must be cleaned regularly, incurring significant time and expense, and the emulsion must be replaced. Cooling lubricants must be applied correctly and disposed of properly, which may only be carried out by specialized and certified companies.

[0007] From DE 42 11 123 C2, a device and method for removing oil films are known. In this process, the oil film is removed by adhesion when a working body is immersed.

[0008] From DE 44 04 010 C1 an oil skimmer is known by means of a partially immersed drum which removes the oil film by means of a circulating belt.

[0009] Further state of the art is known from DE 10 2007 049 845 A1, DE 10 2009 043 110 A1, DE 10 2010 028 116 A1 and US 5 599 457 A.

[0010] Wikipedia, the free encyclopedia, describes how adhesion, or the force of attachment, changes the physical state of an interface layer that forms between two phases in contact, i.e., between solids and liquids. The combination of gravity and capillary force, the driving force, leads to an inhomogeneous film thickness, which, when gas / air is supplied, leads to bubble formation (soap bubble principle).

[0011] Furthermore, Wikipedia, the free encyclopedia, describes how capillarity or the capillary effect changes the behavior of liquids when they enter solids upon contact with capillaries, e.g., narrow tubes, cracks or cavities.

[0012] The invention is based on the objective of proposing a filter system that, in terms of its design and operation, performs better than known methods, devices and systems.

[0013] According to the invention, this problem is solved with a filter system having the features of claim 1.

[0014] This inventive solution proposes a filter system unit with which machines, tanks, and / or containers containing the water-based emulsion can be cleaned of the surface oil / grease film, thus removing the non-emulsifiable oils / greases from the tank and / or containers and preventing the formation of fungal and slime bacteria. The non-emulsifiable oil is retained by the addition of gases / air and through adhesion and capillary action, and then removed from the filter system.

[0015] The suction skimmer, which may also contain a submersible pump, cleans the emulsion and the oil / grease film—that is, the emulsion surface—in the tank or container. This process ensures that the floating oil / grease film is drawn over the edge of the float and initially remains on the surface due to its lower density. The float is supported by an enclosed air cushion at the emulsion surface. This cushion is held in position by a stationary cylinder that extends into the float. A gap exists between the cylinder and the float, with a cross-sectional area that allows approximately 90% of the emulsion flow to be drawn from below the emulsion surface. This effect ensures that the proportion of emulsion oil / grease film is less than 1 / 20 of the extracted liquid volume, thus enabling controlled retention in the filter system.

[0016] In another advantageous embodiment of the skimmer, the stationary cylinder is provided with a closed bottom, thus resembling a cup. Since most skimmer trays are very shallow in design and installed below the machine, resulting in a low emulsion level, it is essential to prevent air turbulence during suction. This is achieved by positioning the suction pipe, preferably in the center of the cup and the float. Spacers securely fix the pipe end within the cup, causing the emulsion to undergo a 180° turn as it is drawn into the pipe. To prevent excessive flow separation at the suction pipe, a flared edge is added. This significantly reduces frictional resistance as the emulsion flow is redirected by the larger flared rim.This means that trumpet formation is impossible even at low skimmer heights.

[0017] The emulsion, loaded with bed oil, can be drawn from the sump or container via the skimmer and pipe connection into the emulsifier filter using negative pressure. This negative pressure is created by the suction and pressure pump located downstream of the emulsifier filter, which pumps the emulsion out. Since the negative pressure causes the emulsion to degas, a gas level control system ensures that the excess gas is removed from the emulsifier filter.

[0018] If several machines are connected to a filter system, the emulsion loaded with bed track oil can also be pumped from the tray or container via the skimmer and pipe connection into a collecting line using a submersible pump and then sucked into the emulsifier filter.

[0019] If several machines are connected to a filter system, the cleaned emulsion can flow back into the tank or container via a distribution line upon leaving the filter system, then via the machine connection line and through an automatic level control valve (e.g., a float valve). This creates a crossflow in the tank or container, causing the cleaned emulsion to move the emulsion loaded with bed oil towards the skimmer for extraction.

[0020] The gas level control ensures that the fill level in the emulsifier filter vessel remains constant, so that the pipe cross-section of the tangential inflow preferentially intersects the surface in the center. The oil- and grease-laden emulsion is set into rotation around the vessel axis by the tangential inflow, creating a uniform surface flow. During this process, the lighter oil and grease components (e.g., slideway oil) detach from the emulsion stream and float to the surface. Filter elements, which are less dense than the emulsion, float on the surface and are thus carried along by the rotating flow. The rotating flow causes the filter elements to collide, breaking up the oil and grease film into tiny micro-droplets, which are then carried along by the adhesive force of the emulsion.

[0021] Designing the filter elements as round bodies is advantageous here, as corners and edges (cubes, cuboids, prisms, or hollow cylinders) inevitably lead to abrasion and tilting of the filter elements. However, since a closed sphere does not provide the desired mixing and comminution effect, it is constructed using platelets. The sphere is advantageously manufactured as a single-piece injection-molded part and consists of spaced-apart plate-shaped elements, which are assembled as two hemispheres. These hemispheres are arranged at an angle of 90° at the equator, forming the intersection points where they merge during injection molding and are thus formed into a single, continuous element.Between the individual plates are gaps which form large inflow areas along the walls that define the gaps, causing turbulence at the edges of the plates which then leads to the desired comminution effect of the oil-grease film.

[0022] In an advantageous embodiment of the level control system, a cylindrical tube is positioned vertically at the center of the emulsifier filter vessel. Starting below the vessel lid, this tube extends downwards into the lid, ensuring a rotational flow around the lid and preventing flow separation at the center of the axis, thus preventing the formation of an oil / grease film. To remove excess gases from the headspace of the emulsifier filter vessel and maintain a consistent surface level, the gases are directed below the lid into the centrally located cylindrical tube. A smaller diameter cylindrical tube is mounted and sealed within the lid. This smaller tube extends along its length to the surface of the emulsion, causing excess gases to flow into it when the emulsion level falls below the required level.Once the excess gases are discharged, emulsion flows into the tubular cylinder in their place. This cylinder is then detected in the level chamber and used to switch the gas discharge on and off via the gas pump. To ensure that no oil slick enters the level control system, the emulsion is supplied from the lower level area of ​​the emulsifier filter.

[0023] To ensure that the rotational flow of the spheres is not disturbed, the space below the surface is filled only with emulsion, so that the underlying filter element bed does not come into contact with the floating spheres. This emulsion space also serves to calm the flow, transforming the rotational flow into a vertical flow. The filter elements have the same shape as the floating spheres described above in

[0020] , but are made of a material that is heavier than the emulsion, so that they lie on the screen bottom as a filter bed.

[0024] The emulsion flows vertically downwards towards the bottom of the emulsifier filter container, flowing around the filter elements, which are made of a diffusion-permeable polyamide plastic. Due to the porosity of the material, the filters become loaded with up to 10% of the substance. Liquids, salts, and gases diffuse into the filter material, creating a continuous osmotic exchange between the emulsion and the filter balls. This encourages the preferential colonization of anaerobic bacteria on the surface of the filter balls. The osmotic exchange provides them with a constant energy supply, enabling them to more effectively break down excess salts. The resulting osmotic pressure can even penetrate a bacterial film, as high pressure differentials can occur. This constant osmotic pressure equalization ensures that the spaces between the filter ball plates do not become blocked.

[0025] The enriched and pre-filtered emulsion flows from the emulsifier filter base and is pumped by the suction-pressure pump into the adhesion filter vessel. During this process, the emulsion is loaded with gas (e.g., air) in the injector, creating a foamy emulsion in the headspace and the gas emulsion distribution chamber. A trickle element then distributes the foamy emulsion onto the filter ball bed below, causing it to become enriched with gas (oxygen) as it flows vertically. The different adhesion properties of the emulsion and the oils / fats separate the phases, resulting in the formation of gas bubbles from the oils / fats. These bubbles then converge on the polyamide balls and, due to gravity, drip through the sieve base and onto the surface. The different densities of the emulsion (approximately 0.98 kg / dm³) further contribute to this process. 3 ) and the oils / fats (approximately 0.85 kg / dm³) 3) The lighter oils / fats gas bubbles float as foam below the sieve bottom on the surface of the emulsion.

[0026] The excess gas and oil / grease foam separate from the emulsion below the sieve bottom, allowing the enriched emulsion to exit the container at the bottom of the adhesion filter. The excess, used gas flows with the oil / grease foam through the exhaust connection into the automatic float drain. As the gases flow from the adhesion filter into the float drain, the oil / grease foam accumulating on the surface is broken up by the bursting of the bubbles, allowing the excess gases to be discharged from the automatic float drain. This creates an oil slick which then flows into the oil collection vessel via the oil separator line.Due to the difference in density between the emulsion and the oil, an underflow / overflow occurs, so that when the lighter oils / greases flow in, the heavier emulsion flows back from the oil collection vessel into the automatic float drain and then exits via the level equalization. The gas-enriched oil / grease separates in the headspace of the oil collection vessel, allowing the excess gas to be vented. The oil / grease layer that accumulates at the bottom can be distinguished from the emulsion using suitable measuring technology (e.g., a detector with an alternating electromagnetic field to differentiate the dielectric properties), thus enabling manual or automatic removal of the oils / greases.

[0027] The gas-enriched emulsion exits the container at the bottom of the adhesion filter and then flows from below into the capillary filter without gas bubbles. The capillary filter container contains the same diffusion-capable filter elements as described in the first two filters. Here, the enriched emulsion flows against gravity over the filter elements, resulting in the capillary retention of the remaining oils / greases between the cavities of the filter plates. The purified emulsion then flows out of the headspace of the capillary filter container and is returned to the sump or container via a pipe or hose connection. This creates a cross-flow within the container, allowing the emulsion to be reused for cooling and lubricating the workpiece and tool.

[0028] If necessary, the cleaning of the emulsion from the tray or container can be interrupted. The emulsion flow between the outlet of the capillary filter and the inlet of the emulsifier filter can then be bypassed. This ensures a controlled gas supply for the bacteria.

[0029] The invention will now be further explained and described with reference to the exemplary embodiments shown in the drawings. Fig. Figure 1 shows a schematic representation of the filter system unit according to the invention in the form of a flow diagram. Fig. Figure 2 shows a schematic representation of the rotational circulation of the filter spheres in the emulsifier filter according to the invention. Fig. Figure 3 shows a schematic representation of the collision of the filter balls according to the invention in the rotational circulation which serves in the emulsifier filter for oil and grease treatment. Fig. Figure 4 shows a cross-sectional view of the skimmer according to the invention with connection from above. Fig. Figure 5 shows a cross-sectional view of the skimmer according to the invention with connection from below. Fig. Figure 6 shows a spatial representation of the filter element according to the invention as filter spheres. Fig. Figure 7 shows a cross-sectional view of the skimmer according to the invention with integrated submersible pump and in Fig. 8 with automatic valve as float valve

[0030] The filter system according to the invention is shown schematically as a whole in Fig. 1 shown.

[0031] The system preferably comprises a machining system (n) and its storage trough (n) and / or container (n) in which the emulsion is held. The inlet and outlet lines to the emulsion trough (n) and / or container (n) containing the emulsion to be cleaned are also included.

[0032] The essential components of the filter system are, firstly, the extraction of the emulsion 5 in conjunction with the proportionate oil / grease film 6 by means of a skimmer 7 as a skimmer extraction connection from above 7a, or, in the case of multiple machines, with the support of a submersible pump in the skimmer and a downstream collection line, or as a skimmer extraction connection from below 7b, depending on the type and design of the emulsion tray / container 4, the emulsifier filter 1, the adhesion filter 2, and the capillary filter 3. The function and construction of the individual components are described below.

[0033] The water-containing emulsion 5 to be cleaned, which is used for cooling and lubricating workpieces and tools during workpiece machining, is removed by means of a skimmer 7 and via the skimmer outlet 11, as shown in more detail in the diagram. Fig. 4 and Fig. 5 described and then introduced by means of a pipe or hose line and then as a tangential inlet 12 into the emulsifier filter 1 for treatment.

[0034] The skimmer 7 simultaneously draws the emulsion 5 and the oil / grease film 6 from the emulsion surface in the emulsion tray / container 4. The floating oil / grease film 6 is drawn in over the edge of the float 10. The float 10 is supported by gases 30a as a gas cushion on the emulsion surface and is held in position by a stationary cylinder that projects into the float 10. A gap exists between the cylinder and the float, the width of which provides a suction capacity of 1–100%, preferably 90%, of the emulsion flow from below the emulsion surface as the skimmer inlet 9. This effect ensures that the emulsion / oil / grease film 6 fraction is less than 1 / 1, preferably less than 1 / 20, of the extracted liquid volume.

[0035] The effective skimmer suction height 7c depends on the delivery rate of the emulsion 5 and the density of the oil-grease film 6, and the downward flow in the skimmer 7. With a downward flow of >0.1 cm / sec but <20 cm / sec, this flow is preferably 1 cm / sec, and with an effective skimmer suction height 7c of >1 cm and <100 cm, preferably 10 cm.

[0036] The stationary cylinder of the Skimmer 7 has a closed bottom. In the version Fig. 4 with upward suction, to prevent air condensation, the skimmer outlet 11 is preferably positioned in the center of the skimmer 7 with a deflector flange 11a and firmly fixed in the cup by means of spacers. In the design Fig. 5 with downward suction, to prevent air trumpet formation, the skimmer outlet 11 is preferably positioned in the center of the skimmer 7 with a deflection cap 11b and fixed firmly in the cup by means of spacers.

[0037] The emulsion 5, loaded with oil-grease film 6, is drawn from the emulsion tray / container 4 via the skimmer 7 and a pipe-hose connection into the emulsifier filter 1 by means of a vacuum. During pumping by means of the suction-pressure pump 27, a vacuum is created in the emulsifier filter 1 and in the emulsion 5. This vacuum is simultaneously used to degas the emulsion 5, and the excess gas is then discharged from the emulsifier filter 1 by means of an automatic level control 17.

[0038] The mechanical level control 15 is a tubular cylinder located in the center of the axis, which leads vertically downwards from below the container lid into the emulsifier filter 1, so that the rotational flow 20 takes place around it, and there is no flow separation in the center of the axis and an oil-grease film 6 builds up here.

[0039] To ensure the surface level of the filter elements floating in the rotational flow < 1 kg / dm² 3In the gas chamber of the emulsifier filter 1, excess gases are discharged from above into the centrally arranged tubular cylinder below the lid. This cylinder is held at a gas-permeable distance from the lid. A second, smaller tubular cylinder, which is attached to and sealed in the lid, extends down to the surface of the emulsion. As the gas chamber 16 expands, excess gases 30a flow from below into the smaller tubular cylinder until the emulsion 5 seals the tube due to the rising gas level.

[0040] Once the excess gases 30a have been removed from the emulsion filter 1 and from the gas space 20, > 1 kg / dm³ flows from below out of the filter elements. 3 24 an oil-grease film 6 free emulsion 5 into the tubular cylinder, this is then detected in the automatic level control and used to switch it.

[0041] Filter elements < 1 kg / dm³ float on the surface of the emulsion chamber 19 in the emulsifier filter 1. 3 18 preferably in spherical form 45, which are set into rotational flow 20 by the tangential inlet 12, around the mechanical level control 15. The filter elements move < 1 kg / dm³ 3 18 the forming oil-grease film 6 Fia. 2 with. In rotational flow 20 this leads to filter element collision 21 which causes small oil-grease droplets to form, Fia. 3 which are then carried along in the downward flow with the emulsion 5.

[0042] The emulsion 5 flows around the filter elements at a rate of > 1 kg / dm². 324 made of a preferred diffusion-capable plastic (polyamide), in which up to 10% of liquids, salts and gases 30a diffuse into the filter element 38, thus ensuring a constant osmotic exchange between the emulsion and the filter element 38. Anaerobic bacteria preferentially colonize the surface of the filter element 38 and are constantly supplied with energy by the osmotic exchange, thereby breaking down some of the excess salts.

[0043] The filter element 38 is preferably designed in a spherical shape 45, as the flow around a bed of spheres guarantees optimal resistance distribution. The osmotic pressure generated by the preferred material (polyamide) can even penetrate a bacterial film, as high pressure differences can occur. This ensures that the spaces between the filter sphere plates do not become blocked due to this constant osmotic pressure equalization.

[0044] The emulsion flows through the sieve plate 25 from the emulsifier filter 1 and is pumped by the suction-pressure pump 27 into the adhesion filter 2. Prior to this, the emulsion 5 is supplied with gas / air in the injector 28, creating a foamy emulsion 5 in the gas emulsion distribution chamber 36. The foamy emulsion 5 is then distributed, preferably in spherical form, onto the filter elements 38 arranged below it by means of a trickle element 37, thus enriching the emulsion 5 with gases 30a and oxygen. The different adhesion properties 38a of the emulsion 5 and the oils / fats separate the phases, causing gas bubbles to form from the oils / fats. These bubbles then converge on the polyamide spheres and, by gravity, drip through the sieve plate 25 and onto the level surface 41a. Due to the different density between the emulsion 5 (approximately 0.98 kg / dm³) 3 ) and the oils / fats (approximately 0.85 kg / dm³) 3) the lighter oils / fats gas bubbles float as oil-fat foam 41b below the sieve bottom 25 on the level surface 41a of the emulsion 5.

[0045] The excess gas 30a and the oil / grease foam 41b separate from the emulsion 5 below the sieve bottom 25, so that the enriched emulsion 5 exits the container at the bottom of the adhesion filter 2. The excess, consumed gas 30a flows with the oil / grease foam 41b via the oil / grease / exhaust connection 40a into the automatic vent 39. As the gas 30a flows from the adhesion filter 2 into the automatic vent 39, the oil / grease foam 41b accumulating on the surface is broken up by the bursting of the bubbles, so that the excess gas 30a is discharged from the automatic vent 39. This forms an oil / grease layer 6a, which then flows into the oil collection vessel 39d via the oil separator connection line 39c.Due to the difference in density between the emulsion 5 and the oil / grease, an underflow / overflow occurs, so that when the lighter oils / greases flow in, the heavier emulsion 5 flows back from the oil collection vessel 39d into the automatic vent 39 and then exits via the level control 41. The oil / grease enriched with gases 30a separates in the headspace of the oil collection vessel 39d, so that the excess gas is discharged via the vent 39e. The oil / grease layer 6a, which accumulates downwards, can be distinguished from the emulsion 5 using suitable measuring technology (e.g., detector 39a with an alternating electromagnetic field to differentiate the dielectric properties), thus enabling manual or automatic discharge of the oils / greases.

[0046] The gas-enriched emulsion 5 exits the container at the bottom of the adhesion filter 2 and then flows without gas bubbles from below into the capillary filter 3. The same diffusion-capable filter elements 38, as described in the first two filters, are used in the capillary filter 3 container. Here, the enriched emulsion 5 flows against gravity over the filter elements 38, allowing the remaining oils / greases to be retained capillarily between the cavities of the filter plates. The purified emulsion 5 then flows out of the capillary filter 3 in the headspace as a return flow 44, and is returned to the emulsion tank / container 4 via a pipe or hose connection. This creates a cross-flow in the emulsion tank / container 4, allowing the emulsion 5 to be used again for cooling and lubricating the workpiece and tool.

[0047] If necessary, the cleaning of the emulsion 5 from the emulsion tray / container 4 can be interrupted. The emulsion flow between the outlet of the capillary filter 3 and the inlet of the emulsifier filter 1 can then be short-circuited in bypass 46. This ensures an adjusted gas / air supply 30 to the bacteria via the flow regulator 31.

[0048] The emulsion 5 flows against gravity from the bottom of the container upwards in the headspace of the capillary filter 3. During this flow, the buffered gases 30a from the emulsion 5 expand because the pressure resistance in the capillary filter 3 is lower than in the adhesion filter 2. This gas expansion can be determined using the oxygen sensor SS, as its setting indicates the saturation limit of the liquid, the emulsion 5. For example, fresh water at 20°C normal pressure (1013 mbar) can buffer approximately 9.1 mg / l of oxygen, which corresponds to 100% saturation. At an overpressure of approximately 100 mbar (1113 mbar), this is about 10 mg / l, and consequently 110% saturation. This pressure decreases during the upward flow in the capillary filter 3 because the static liquid column decreases towards the top of the capillary filter 5.Due to the pressure reduction, the buffered gases 30a expand, creating small gas bubbles which then absorb residual oils and greases onto their surface that were not retained in the adhesion filter 2, the automatic deaerator 39, and the oil collection container 39d. A conductivity probe, also installed in the headspace of the capillary filter, measures the salt content of the emulsion 5. The measurement is given in µS / cm. This value is 0 µS / cm for distilled water, as no salts are present. For domestic tap water, the value is approximately 400–700 µS / cm. For an emulsion, this value can be much higher due to water evaporation and dirt contamination during processing, potentially exceeding 1000 µS / cm. A conductivity probe operates on the principle of resistance, where an electrical voltage is applied between two, for example,Stainless steel electrodes are positioned so that a few millivolts are measured at the positive electrode via the liquid resistance of the emulsion as a function of temperature at the second negative electrode. It has been shown that in liquids without an oil or grease film 6, a nearly stable value is displayed. If gas bubbles laden with oil or grease flow over the electrodes, the contact between the liquid and the electrode is temporarily reduced, and thus the measured and displayed conductance is also affected by the oil or grease deposits. This can lead to fluctuations in the measured value of several hundred µS / cm, or even several thousand µS / cm. These fluctuations stabilize the lower the oil or grease foam in the emulsion 5. This phenomenon can therefore be used as an indicator and as a control variable for a purified emulsion 5 and can thus be used to control the pressure resistance, the emulsion flow, and gas enrichment.

[0049] The Fig. Figure 7 shows an embodiment in which a submersible pump 47 is used in the skimmer 7 to pump out the oily grease film. Fig. Figure 8 shows an inlet regulator in the form of an automatic float valve 48 in the emulsion in the return line of the filter system to the emulsion tank / container, with which the quantity of the returned cleaned material is regulated so that a certain fill level in the emulsion tank / container 4 can be maintained.

[0050] How Fig.As shown in Figure 9, the filter system can also be used to process emulsions from several processing machines. The emulsions from the individual emulsion tanks / containers 4 are preferably fed to a collective supply line SV by means of submersible pumps 47 and from there to the emulsifier filter 1. The return flow occurs via a collective return line SR, from which individual lines LR lead via the float valves 48 into the individual emulsion tanks / containers 4 of the respective machine. Reference symbol list 1 emulsifier filter 2 adhesion filters 3 capillary filters 4 Emulsion tray / container 5 Emulsion 6 Oil-grease film 6a Oil-grease layer 7 skimmers 7a Skimmer suction connection from above 7b Skimmer suction connection from below 7c Effective skimmer suction height 8 Skimmer inlet at top 9 Skimmer inlet bottom 10 floats 11 Skimmer drain 11a Deflection flange 11b Deflection hat 11c Intake 12 Tangential inlet 13 Rinse valve 14 Flushing fluid inlet 15 Mechanical level control 16 Gas chamber 17 Automatic level control 18 filter elements < 1 kg / dm³ 3 19 Emulsion chamber 20 Rotational flow 21 Filter element collision 22 oil-fat drops 23 Emulsion formation 24 filter elements > 1 kg / dm³ 3 25 sieve tray 26 Drain emulsifier filter 27 Suction-pressure pump 28 injectors 29 sight glass 30 Gas / Air Supply 30a Gases 31 Flow regulators 32 backflow preventers 33 Inlet adhesion filter 34 Pressure monitoring 35 Ventilation 36 Gas emulsion distribution room 37 trickle element 38 filter elements 38a Adhesive effect 38b Capillary action 39 Automatic air vent 39a Detector (Oil / Water / Emulsion) 39b Excise (oil / water / emulsion) 39c Oil separator connection line 39d Oil collection vessel 39e Ventilation 40 Exhaust air 40a Oil-grease foam / exhaust connection 41 Leveling 41a Level surface (oil / water / emulsion) 41b Oil-grease foam 42 Inlet capillary filter 43 Temperature monitoring 44 Return 45 Spherical shape 46 Bypass 47 Submersible pump 48 Automatic float valve LS conductance probe (measured value in µS / cm) SS oxygen probe (measured value in % saturation of the emulsion as a function of temperature) SV Collective Pre-flight Line SR Collective Return Line LR return line

Claims

[1] Filter system for removing undissolved oils and greases from aqueous emulsions in containers and vats used for holding and storing emulsions used for cooling and lubricating workpieces and tools during machining, with at least - a tangential inlet (12) - into the emulsifier filter (1) - a subsequent injector for gas enrichment (28), - a downstream adhesion filter (2) with automatic vent (39) - an oil collection vessel (39d) with drain (39b) and - a subsequent capillary filter (3), wherein a skimmer (7) with a suction connection from below is provided for the extraction of the emulsion (5) and the oil / grease film (6) from the emulsion tray / emulsion container (4), wherein the filter system as a unit mechanically, physically and biologically treats the emulsion (5) with the insoluble oil / grease droplets (22) so that the oil / grease layer (6) is then removed from the filter system. [2] Filter system according to claim 1, characterized by , that the skimmer (7) is designed in such a way that both the emulsion (5) and the oil-grease film (6) can enter the skimmer from the emulsion surface and be extracted from the emulsion tray / container (4). [3] Filter system according to claim 1, characterized by , that the effective skimmer suction height (7c) depends on the delivery rate of the emulsion (5) and the density of the oil-grease film (6), and the downward flow in the skimmer (7) and the downward flow is >0.1 cm / sec and <20 cm / sec, preferably 1 cm / sec, and at an effective skimmer suction height (7c) is >1 cm and <100 cm, preferably 10 cm. [4] Filter system according to any of the preceding claims, characterized by, that the emulsion (5) loaded with oil-grease film (6) is drawn into the emulsifier filter (1) by means of a suction-pressure pump (27) under negative pressure via a pipe or hose connection.

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