DE102019216249A1 - Oil removal device with oil removal filter - Google Patents

Abstract

The present invention relates to an oil removal filter (6) for separating oil from water, the oil removal filter (6) having a hollow cylindrical filter body (16) through which water can flow radially. A particularly efficient oil separation can be achieved if the filter body (16 ) has a cylindrically arranged outer filter layer (20) with mineral wool (22) and a cylindrically arranged inner filter layer (21) with a multi-layer filter material (23), which is arranged radially inside the outer filter layer (20), and if the multi-layer filter material ( 23) of the inner filter layer (21) has an inner prefilter layer (24) and an outer main filter layer (25), a pore size in the main filter layer (25) being smaller than in the prefilter layer (24).

Description

The present invention relates to a de-oiling filter for separating oil from water. The invention also relates to a de-oiling device for separating oil from water, which is equipped with such a de-oiling filter.

In a variety of industrial applications, water can be contaminated with an oily substance, so that in order to dispose of the water it is necessary to separate the oily substance from the water. Of particular interest are maritime applications in which the water is to be disposed of in a lake, river or sea. In particular, the present invention is concerned with the separation of oily substances, such as, for example, lubricating oil, heating oil and oily fuel, in particular diesel fuel or diesel oil, from the bilge water of a ship. To this extent, the present invention also relates to a bilge water treatment system or a bilge water drainage device.

The de-oiling of water, that is to say the separation of oil from water, can take place within the de-oiling device in a single de-oiling stage or preferably in several de-oiling stages. Such a de-oiling stage can work with the aid of a de-oiling filter through which the water contaminated with oil flows through it. For this purpose, the oil removal filter has a filter body through which water can flow and which, as it flows through, shows a separation effect for the oil contained in the water. The oil-water mixture can be in the form of an emulsion or dispersion. The flow through the oil removal filter can more or less separate this emulsion or dispersion into the separate components oil and water in a separator designed as a separator or working as a separator, so that downstream of the oil removal filter in the flow due to the different density of oil and water Separation takes place, for example in a calming section, which simplifies the separation of oil and water. It is also possible that in a coalescer designed as a coalescer or working as a coalescer, the filter body has a sorption effect for the oil and retains and accumulates in the filter body, so that it is possible, depending on the structure of the oil removal device, to drain the oil directly from the oil removal filter.

The oil removal filter of a main oil removal stage usually causes the oil to be retained in the filter body and enables the oil to be discharged in the area of the oil removal filter. This retention effect is usually based on adsorption or absorption or adhesion or any combination thereof. In contrast to this, in a deoiling filter of a deoiling preliminary stage, which can also be referred to as a deoiling prefilter and which can optionally be used in addition and upstream of the deoiling filter, a separation of oil and water within the emulsion or dispersion is usually achieved, so that oil and water downstream of the deoiling prefilter can be separated due to the force of gravity due to the different density and can accordingly be discharged separately in a correspondingly simplified manner.

In practice, oil removal filters have proven to be particularly advantageous which have a hollow cylindrical filter body through which the water to be cleaned can flow radially. The oil removal filter can also have two end plates, which are each arranged on an axial end face of the hollow cylindrical filter body. The axial direction is defined by the longitudinal center axis of the hollow cylindrical filter body. In principle, different filter materials are available for realizing the filter body. Embodiments in which a folded sheet material is used to produce the filter body are widespread.

The present invention is concerned with the problem of specifying an improved or at least another embodiment for a de-oiling filter of the type described above or for a de-oiling device equipped therewith, which is characterized in particular by a high separation effect with a compact and inexpensive design.

According to the invention, this problem is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea of building the filter body in several stages, in such a way that it has several filter stages through which the water to be de-oiled flows in succession during operation of the oil removal filter. The invention is based on a de-oiling filter which has a hollow cylindrical filter body through which water can flow radially. This filter body now has a cylindrically arranged outer filter layer with mineral wool and a cylindrically arranged inner filter layer with a multilayer filter material, the inner filter layer being arranged radially inside the outer filter layer. The multilayer filter material of the inner filter layer has an inner prefilter layer facing away from the outer filter layer and an outer main filter layer facing the outer filter layer. It is of crucial importance that a pore size in the Main filter layer is smaller than in the pre-filter layer. Investigations by the applicant have shown that the proposed multi-stage structure of the filter body enables a particularly efficient separation effect for oil-containing contaminants from water to be achieved. The pre-filter layer through which the water flows first enables the separation of comparatively coarse impurities. Due to its smaller pore size, the main filter layer through which the air flows subsequently enables the separation of small impurities. The outer filter layer, which is subsequently flowed through, enables the separation of the smallest impurities in the mineral wool. The coordination of the individual filter stages with one another and in particular the sequence provided here enable a particularly efficient separation effect for the oil-containing impurities from water.

According to an advantageous embodiment, the pore size in the pre-filter layer can be at least five times larger than in the main filter layer. In other words, the pore size in the main filter layer is at least five times smaller than in the pre-filter layer. This ensures that a large part of the impurities can already be separated out in the pre-filter layer, so that the main filter layer can be protected from the comparatively coarse impurities that are captured in the pre-filter layer. In this way, the main filter layer can develop its filter effect better and more efficiently for the smaller contaminants.

For example, the pre-filter layer can have a pore size in the range of 60-120 μm. Additionally or alternatively, it can be provided that the main filter layer has a pore size in the range of 6-14 μm. In particular, the pore size of the prefilter layer can be smaller than 100 μm. Additionally or alternatively, the pore size of the main filter layer can be smaller than 10 µm.

Another advantageous embodiment suggests that the prefilter layer has cellulose fibers as the main component. These cellulose fibers can, for example, form a fleece. Additionally or alternatively, the main filter layer can have glass fibers as the main component. Glass fibers can be made with significantly smaller fiber strengths than cellulose fibers. The main constituent is present in the respective filter layer to an extent of more than 75%, preferably more than 85% and in particular more than 90% or more than 95%, in each case based on the volume.

Optionally, the prefilter layer can have a resin, such as phenolic resin, in order to fix the cellulose fibers to one another. As an alternative to a resin binder, in particular an epoxy resin binder, an epoxy binder can also be used to fix the cellulose fibers. However, the hydrophobic property of the prefilter layer is then not so pronounced. Additionally or alternatively, the main filter layer can have a sandwich structure in which a core formed by the glass fibers is laminated on one or both sides by a protective layer made of plastic, such as polyethylene terephthalate (PET). Through this sandwich structure, the glass fibers are held on the respective protective layer or held together between the two protective layers. In the core, the glass fibers can be held or fixed to one another by means of a binder, in particular by means of an acrylate binder. The respective protective layer, on the other hand, can be held or fixed on the glass fiber core by means of an adhesive, in particular by means of a hotmelt.

In principle, the pre-filter layer and the main filter layer can form separate filter materials. Alternatively, the pre-filter layer and the main filter layer can be formed together in one filter material. For this purpose, the inner filter layer can be designed as a sandwich structure in which the main filter layer with or made of glass fibers is held directly on the prefilter layer with or made of cellulose fibers, for example by means of an adhesive, preferably by means of a hotmelt. Optionally, on the side of the main filter layer facing away from the prefilter layer, a protective layer made of plastic, such as polyethylene terephthalate (PET), can also be arranged on the main filter layer and held or fixed to it by means of an adhesive, in particular by means of a hotmelt. In particular, a glass fiber core can then be arranged between the protective layer and the cellulose layer in order to form the sandwich structure of the inner filter layer.

An embodiment is particularly useful in which the mineral wool of the outer filter layer is shape-stabilized with a resin so that it forms a molded body. This shaped body can be designed in one piece or in several pieces. In other words, the filter body comprises one or more dimensionally stable molded bodies in the outer filter layer which are made from a mineral wool which is dimensionally stabilized with the aid of a resin. The respective molded body is designed monolithically, that is, has a continuous, coherent structure and thus represents a single component that is not assembled from several individual parts. The mineral wool, which is dimensionally stabilized with the aid of the resin, already forms the respective dimensionally stable shaped body with the desired geometry, so that the shaped body forms the hollow cylinder of the outer filter layer. The respective shaped body can form a section of the hollow cylindrical outer filter layer with respect to the axial direction and / or with respect to the circumferential direction, but preferably extends over the entire radial wall thickness of the outer filter layer. Thus, the respective shaped body differs significantly from a flexible web material that can be wound spirally in order to form a conventional filter body or a conventional filter layer. It has been shown that a filter layer which is formed from mineral wool stabilized with resin with the aid of at least one shaped body of this type can achieve a particularly effective separation effect for the oil from the water.

According to a particularly advantageous embodiment, the resin can contain phenol and formaldehyde to stabilize the shape of the mineral wool. In other words, said resin is made on a phenol and formaldehyde basis. It has been shown that the use of such a resin promotes a particularly long service life for the dimensionally stable molded body.

An embodiment in which the mineral wool is formed by rock wool is particularly advantageous. The use of rock wool to produce the shape-stabilized molded bodies with resin has proven to be particularly efficient for separating oil from water.

Furthermore, an embodiment is preferred in which the respective shaped body has a density in the range from 0.05 to 1.5 kg / dm ³ . A density range of 0.8 to 1.2 kg / dm ³ is particularly advantageous. Within this density range, in particular in the preferred density range, there is a particularly efficient separation effect for the oil from the water.

According to an advantageous embodiment, the filter body can also have a cylindrical frame which is arranged radially between the outer layer and the inner layer. The cylindrical frame can have a lattice structure. It can basically be made of a plastic. However, depending on the prevailing pressure conditions, the frame can also be made of a metal. When the flow direction of the filter body is provided from radially inside to radially outside, it is provided that the inner filter layer is supported radially on the frame. This can be done immediately. To avoid damage to the inner filter layer due to relative movements on the frame, a suitable protective layer can also be provided radially between the inner filter layer and the frame. It is clear that the liquid to be cleaned can flow through this protective layer as well as the frame. The frame can in particular be designed as a perforated plate.

The oil removal filter can also expediently have two end disks, which are each arranged on an axial end face of the filter body and are each firmly connected to the outer filter layer and to the inner filter layer. If the frame mentioned above is present, the end plates can in principle also be firmly connected to this frame. The end disks form an axial seal for the filter body and simplify the integration of the oil removal filter in a suitable filter housing of an oil removal device.

In another advantageous embodiment, the oil removal filter can also have a pretensioning jacket that rests radially on the outside with radial pretensioning on the filter body. The prestressing jacket consists of an elastically deformable material that has to be elastically expanded in order to pull it onto the filter body, which creates a radially inwardly directed prestressing. In particular, the prestressing jacket can be designed as a shrink jacket which is shrunk onto the filter body radially on the outside, preferably thermally, and bears against it in a prestressed manner. The prestressing jacket or the shrink jacket consists of a material through which water can also flow. The prestressing jacket or the shrink jacket can serve to stabilize the outer filter layer of the filter body. In particular in embodiments in which a plurality of shaped bodies made of mineral wool are used to form the outer filter layer, the prestressing jacket or the shrink jacket can serve to fix the individual shaped bodies relative to one another. In other words, the respective jacket causes the separate molded bodies to be fixed in position within the outer filter layer.

The aforementioned end disks can be firmly and tightly connected in a suitable manner to the respective adjoining filter layer. For example, an adhesive connection is conceivable. Such an adhesive connection is preferably used when the respective end disk is designed as a shell, preferably made of metal, into which the filter body or the filter layers are inserted axially at the front. It is also conceivable to firmly connect the end disks, if they are made of a plastic, to the respective filter layer or to the filter body by means of plasticization. During plasticizing, the plastic of the end plates is liquefied by a thermal treatment to such an extent that the respective filter layer can be embedded in the plastic of the respective end plate without melting itself. It is also conceivable to foam or inject the plastic end disks onto the respective filter layer.

According to an advantageous embodiment, the inner filter layer can be folded in a star shape in order to significantly increase the surface of the inner filter layer through which the air flows. End folds that adjoin one another in the circumferential direction can expediently be attached to one another by gluing along the longitudinal seams. As a result, the folded, ring-shaped inner filter layer is tightly closed in the circumferential direction. A particularly high level of pressure stability can be achieved in that the longitudinal seam gluing is carried out in such a way that the adhesive material wets the penultimate fold immediately adjacent to the respective end fold via a fold and covers the free end edges of the end folds radially. In addition, the adhesive fills the respective pocket which is formed between the respective end fold and the adjacent penultimate fold. As a result, the abutting end folds on the outer side of the inner filter layer facing the outer filter layer are enclosed on three sides. This realizes a particularly high level of pressure resistance and tightness.

The retention effect of the oil removal filter for oil formed by adsorption or absorption or adhesion or any combination thereof or the coalescer effect of the oil removal filter can optionally be improved by the following measures, whereby the measures mentioned can be implemented alternatively or in any combination or preferably cumulatively.

For example, the outer filter layer can be designed to be oleophilic and hydrophobic.

For example, the mineral wool of the outer filter layer can be designed to be oleophilic and hydrophobic.

For example, the mineral wool of the outer filter layer can be made oleophilic and hydrophobic by means of a phenolic resin or by means of an epoxy binder, with which the mineral wool is shape-stabilized. This form stabilization of the mineral wool by means of resin has already been presented above.

For example, the main filter layer can be designed to be oleophilic and hydrophilic.

For example, the main filter layer can have glass fibers and be designed to be oleophilic and hydrophilic by means of a binder, preferably by means of an acrylate binder, with which the glass fibers are stabilized, that is to say are fixed to one another.

For example, the prefilter layer can be designed to be oleophilic and hydrophobic.

For example, the prefilter layer can have cellulose fibers and be designed oleophilic and hydrophobic by means of a phenolic resin or by means of an epoxy resin, with which the cellulose fibers are stabilized, that is to say are fixed to one another.

The main filter layer can advantageously be designed to be oleophilic and hydrophilic, while at the same time the prefilter layer is designed to be oleophilic and hydrophobic.

The outer filter layer can particularly advantageously be configured to be oleophilic and hydrophobic, while on the one hand the main filter layer is configured to be oleophilic and hydrophilic and, on the other hand, the prefilter layer is configured to be oleophilic and hydrophobic.

An embodiment is useful in which the main filter layer has a glass fiber layer or is formed by a glass fiber layer and in which the pre-filter layer has a cellulose fiber layer or a cellulose layer or is formed by a cellulose layer, the cellulose layer of the pre-filter layer lying directly on the glass fiber layer of the main filter layer. As a result, the main filter layer and the pre-filter layer are combined so that they form a unit. In particular, with a given filtration area, the pack size can be reduced or, given a given pack size, the available filtration area can be increased. It can optionally be provided that the prefilter layer is fixed to the main filter layer or the cellulose layer to the glass fiber layer by means of an adhesive.

A further development is particularly advantageous in which the glass fibers of the glass fiber layer of the main filter layer are stabilized by means of an acrylate binder, while the cellulose fibers of the cellulose fiber layer of the prefilter layer are stabilized by means of a phenolic resin. In this way, the coalescing effect or the de-oiling effect can be improved.

An oil removal device according to the invention for separating oil from water comprises a filter housing and an oil removal filter of the type described above, which is arranged in the filter housing. Furthermore, the oil removal device can expediently be equipped with a raw water inlet, through which water contaminated with oil can be fed, and with a pure water outlet, through which water freed from oil can be discharged. Furthermore, an oil outlet can expediently be provided through which oil separated from the water can be discharged. The oil removal filter arranged in the filter housing appropriately separates in the filter housing a raw space fluidly connected to the raw water inlet from a clean room fluidically connected to the pure water outlet. The oil outlet expediently discharges the separated oil on the raw side, i.e. out of the raw space.

According to an advantageous development, the oil removal device can also have a water flow upstream of the Have oil removal filter arranged oil removal prefilter. The de-oiling prefilter can have a fully cylindrical prefilter body through which a flow can flow axially. An embodiment in which the prefilter body is formed by a web material wound up in a spiral shape is particularly advantageous. With the help of such a deoiling prefilter, the emulsion or dispersion of oil in water as it flows through the deoiling prefilter can be separated so far that there is a gravity-related separation of oil and water due to the different densities downstream of the deoiling prefilter, especially in a calming zone with reduced flow velocity adjusts. In this respect, an efficient pre-separation of oil can be realized with the help of such a deoiling prefilter, so that small and extremely small oil particles can be separated from the water in the downstream deoiling filter, which serves as a kind of main deoiling filter.

The use of a spirally wound web material for realizing the fully cylindrical prefilter body has proven to be particularly inexpensive.

According to a particularly advantageous embodiment, the rolled-up web material can be radially compressed in the prefilter body. As a result, the structure of the web material is compressed within the prefilter body, which improves the separation effect or separation effect of the deoiling prefilter.

A configuration in which the wound web material in the pre-filter body is compressed by at least 3%, in particular by at least 5%, is particularly advantageous. A compression of more than 10% is also conceivable. However, the compression is preferably less than 20%. This compression is to be understood in comparison to the uncompressed initial state of the web material.

An embodiment has been found to be particularly advantageous in which the web material is formed by a three-dimensional random structure made of plastic. Such a three-dimensional random structure is, for example, from DE 100 61 839 B4 known. It has been shown that a deoiling prefilter, the prefilter body of which is produced with the help of the random structure, enables particularly efficient pre-separation for the oil. In addition, such a random structure can be obtained inexpensively, so that the de-oiling prefilter can be manufactured inexpensively.

Additionally or alternatively, the web material can be formed by a non-directional scrim made of plastic. Depending on the configuration, such a thread lay-up can correspond to a random lay-up. In particular, the terms “random scrim” and “undirected filamentary scrim” can then be synonyms. In the case of the scrim or random scrim, at least one plastic thread is laid flat, that is, two-dimensional and one above the other, that is, three-dimensional. There is a permanent connection at the contact points, usually by fusion. A large number of plastic threads are expediently laid at the same time, as a result of which the web material can be manufactured particularly inexpensively.

According to an advantageous embodiment, the web material, in particular the random laid or the thread laid, can be made of polypropylene.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures on the basis of the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components.

Figure list

• 1 a greatly simplified, circuit diagram-like principle representation of a de-oiling device,
• 2 a simplified cross-section of a de-oiling filter of the de-oiling device,
• 3 an enlarged detail III of the oil removal filter from the cross section of FIG 2 ,
• 4th a simplified cross-section of a deoiling prefilter of the deoiling device,
• 5 a simplified longitudinal section of the deoiling prefilter,
• 6th a plan view of a section of a web material for forming the de-oiling prefilter,
• 7th a greatly simplified sectional view of an inner filter layer of the oil removal filter in a first embodiment,
• 8th a greatly simplified sectional view of an inner filter layer of the oil removal filter in a second embodiment.

Corresponding 1 includes a de-oiling device 1 , which is used to separate oil from water, a filter housing 2 , a raw water inlet 3 , a pure water outlet 4th and at least one oil outlet 5 . There is also a de-oiling filter 6th provided in the filter housing 2 is arranged. The raw water inlet 3 enables water contaminated with oil to be fed in. The pure water outlet 4th enables water that has been more or less freed from oil to be discharged. The oil outlet 5 allows oil separated from the water to be drained away. The oil removal filter 6th separates in the filter housing 2 a raw room 7th , the one with the raw water inlet 3 is fluidically connected, from a clean room 8th , the one with the pure water outlet 4th is fluidically connected. The oil outlet is useful 5 to the raw room 7th connected.

In the example shown, the 1 is the de-oiling device 1 also with a de-oiling prefilter 9 equipped in a pre-filter housing 10 is housed. Regarding the flow of water in 1 is indicated by arrows, the oil removal pre-filter 9 upstream of the de-oiling filter 6th arranged. This oil removal pre-filter 9 separates in the pre-filter housing 10 another raw room 11 , the one with the raw water inlet 3 is fluidically connected to another clean room 12th , the one with the pure water outlet 4th is fluidically connected. There is also another oil outlet 13th provided on a calming stretch 14th is connected, which is located between the pre-filter housing 10 and the filter housing 2 extends. In the de-oiling prefilter 9 , which works like a separator, there is a separation of the oil-water emulsion or oil-water dispersion, at least partially, in such a way that in the subsequent calming section 14th Because of the different density of oil and water, a separation of oil and water can take place due to gravity. Within the calming section 14th is in 1 a separation line 15th indicated with a broken line. Above this is the oil. Below this is the pre-cleaned water, which, however, is still contaminated with oil. In the subsequent de-oiling filter 6th the remaining oil is then separated up to a desired degree of separation, with the separated oil in the de-oiling filter 6th accumulated and from it through the oil outlet 5 is deductible. The oil removal filter 6th acts like a coalescer, so that with the de-oiling filter 6th Oil coming into contact adheres to it, coalesces into larger drops and can ultimately be removed.

Corresponding 2 includes the de-oiling filter 6th a hollow cylindrical filter body 16 through which water can flow radially, preferably from radially inside to radially outside. A corresponding through-flow is indicated by an arrow and denoted by 17. The radial direction runs perpendicular to an axial direction that is parallel to a central longitudinal axis 18th of the filter body 16 that runs in 2 is perpendicular to the plane of the drawing. In addition, in 2 a circumferential direction 19th indicated by a double arrow around the central longitudinal axis 18th running around.

The filter body 16 has a cylindrically arranged outer filter layer 20th and a cylindrically arranged inner filter layer 21 on, the radially inward of the outer filter layer 20th is arranged. The oil removal filter is in operation 6th preferably flows through from radially inside to radially outside, so that the inner filter layer 21 in front of the outer filter layer 20th is flowed through. The outer filter layer 20th is with mineral wool 22nd formed, the inner filter layer 21 is with a multilayer filter material 23 educated.

Corresponding 3 includes the multilayer filter material 23 the inner filter layer 21 an internal pre-filter layer 24 by the outer filter layer 20th facing away, and an external main filter layer 25th that of the outer filter layer 20th is facing. Pre-filter layer 24 and main filter layer 25th differ in their pore size, whereby the pore size in the main filter layer 25th is smaller than in the pre-filter layer 24 . For example, the pore size is in the pre-filter layer 24 at least five times larger than in the main filter layer 25th . For example, the pre-filter layer 24 have a pore size in the range of 60-120 µm. An embodiment is preferred in which the prefilter layer has a pore size of 90 ± 15 μm. The main filter layer can expediently 25th have a pore size in the range of 6-14 µm. An embodiment is preferred in which the main filter layer has a pore size of 10 ± 2 μm.

According to the 7th and 8th can the pre-filter layer 24 as cellulose material or cellulose fiber layer or cellulose layer 49 be designed and accordingly have cellulose fibers as the main component, which in particular can be fixed or stabilized with a resin such as phenolic resin. In particular, the pre-filter layer 24 be formed by a cellulose fleece. The main filter layer can expediently 25th as glass fiber material or glass fiber layer 50 be designed and accordingly have glass fibers as the main component.

It is advantageous according to 7th an embodiment in which the main filter layer 25th a sandwich structure 51 having a core formed by the glass fibers, so the glass fiber layer 50 as well as a protective layer 52 , but preferably two protective layers 52 made of plastic, which conceal the core made of glass fibers on both sides. The plastic for the protective layers 52 can for example be PET, i.e. polyethylene terephthalate. Inside the sandwich structure 51 can the protective layers 52 Position and fixate the core's glass fibers. In 7th are the pre-filter layer 24 and the main filter layer 25th separate filter materials. The pre-filter layer 24 can differ from the representation of the 7th directly on the main filter layer 25th apply, such as in 3 shown.

It is particularly advantageous according to 8th an alternative embodiment in which the entire inner filter layer 21 as a sandwich structure 53 is designed. This is the pre-filter layer 24 and the main filter layer 25th combined in a common filter material. In this sandwich structure 53 is the one as a fiberglass layer 50 designed main filter layer 25th directly on the cellulose layer 49 designed pre-filter layer 24 which is arranged from cellulose fibers. Preferably the cellulose layer can 49 by means of an adhesive 54 , preferably by means of a hot melt, on the glass fiber layer 50 be fixed. Optionally, according to 8th at that of the pre-filter layer 24 facing away from the main filter layer 25th , i.e. an additional protective layer on the downstream side 52 made of plastic, such as polyethylene terephthalate (PET), on the main filter layer 25th be arranged and with an adhesive 54 be held or fixed thereon, in particular by means of a hotmelt. This gets inside the sandwich structure 53 the inner filter layer 21 the above too 7th presented sandwich structure 51 the main filter layer 25th realized with one-sided lamination. In the example of the 8th is therefore a fiberglass core, i.e. the fiberglass layer 50 between the protective layer 52 and the cellulose layer 49 arranged to the sandwich structure 53 the inner filter layer 21 to build.

The mineral wool 22nd the outer filter layer 20th can be shape-stabilized with a resin, in such a way that the mineral wool which is shape-stabilized with resin 22nd at least one shaped body 26th forms. It can be provided that the entire outer filter layer 20th by a single such shaped body 26th is formed. Several such shaped bodies can also be used 26th be provided which put together the outer filter layer 20th form. For example, several moldings 26th axially abut one another around the outer filter layer 20th to build. The resin to stabilize the shape of the mineral wool 22nd can be formed by a mixture of phenol and formaldehyde. The mineral wool 22nd is preferably formed by rock wool.

According to the 2 and 3 can the filter body 16 also a cylindrical frame 27 have radially between the outer filter layer 20th and the inner filter layer 21 is arranged. The outer filter layer is expediently supported 20th and the inner filter layer 21 radially on the frame 27 from. The frame 27 has a structure that is permeable to water. For example, the frame 27 be designed as a perforated plate or as a grid. The frame is preferred 27 made of a metal so that it can support high pressure differentials.

The oil removal filter 6th can also have two end plates, not shown here, each on an axial end face of the cylindrical filter body 16 are arranged and each with the outer filter layer 20th and the inner filter layer 21 are firmly connected. Provided that the frame is here as well 27 is present, these end plates can also expediently with this frame 27 be firmly connected.

According to the 2 and 3 can use the de-oiling filter 6th also with a prestressing jacket 28 be equipped. The preload jacket 28 envelops the entire filter body 16 in the circumferential direction 19th and expediently lies radially on the outside under radial prestress on the filter body 16 and thus on the outer filter layer 20th at. In particular, this prestressing jacket 28 as a shrink coat 29 designed to be radially outward on the filter body 16 or on the outer filter layer 20th is shrunk and thereby rests on it under radial prestress. In particular, the outer filter layer can thereby 20th radially against the frame 27 be biased.

According to the 2 and 3 can be provided in a preferred embodiment that the inner filter layer 21 Is folded in a star shape, that is, is formed from a folded sheet-like filter material. The quasi-endlessly provided web material is folded and then arranged cylindrically. As a result, there are large ends 30th of the annularly arranged, pleated filter material in the circumferential direction 19th to each other to the system. The pleated filter material has at each peripheral end 30th an end fold 31 with the two end folds in the circumferential direction 19th rest against each other. The two end folds are useful 31 by gluing longitudinal seams 32 attached to each other. At the same time, the joint of the folded filter material is sealed off radially. In 3 is a special embodiment for this longitudinal seam bonding 32 reproduced. The longitudinal seam bonding 32 is designed here so that the end folds 31 are embedded in it. For this purpose, an adhesive mass fills 33 the longitudinal seam bonding 32 Bags 34 off, each between the respective end fold 31 and one over a fold 35 immediately following another fold 36 is trained. In addition, the adhesive mass engages 33 the free edges 37 of the end folds 31 radially outside.

According to the 4th and 5 possesses the above with reference to FIG 1 featured De-oiling prefilter 9 a fully cylindrical pre-filter body 38 which can be axially traversed. A flow through the pre-filter body 38 is in 5 by corresponding flow arrows 39 indicated. Here, too, the axial direction of the de-oiling prefilter is 9 through the cylindrical pre-filter body 38 Are defined. The pre-filter body 38 namely has a longitudinal central axis 40 showing the axial direction of the deoiling prefilter 9 Are defined. The axial direction extends parallel to the longitudinal center axis 40 . The associated radial direction runs transversely to the axial direction and is in particular perpendicular to the longitudinal center axis 40 . The corresponding circumferential direction 41 runs around the longitudinal center axis 40 around.

The fully cylindrical pre-filter body 38 is according to a preferred and in the 4th and 5 embodiment shown by a sheet material 42 formed with respect to the longitudinal central axis 40 is preferably wound spirally. There is an inner longitudinal end for realizing the solid body 43 of the web material 42 in the area of the longitudinal center axis 40 , while an outer longitudinal end 44 of the web material 42 on the outer circumference of the pre-filter body 38 lies.

The web material used here 42 is flexible, so that on the one hand it can simply be wound in a spiral. On the other hand, the web material 42 also compress elastically. The wound web material is preferred 42 in the pre-filter body 38 radially compressed, in particular by at least 3 or 4 or 5%. This means that in the compressed state, i.e. within the built-in pre-filter body 38 a radial wall thickness 45 of the compressed web material 42 is at least 3 or 4 or 5% less than in an uncompressed initial state, i.e. in particular before the web material 42 spiral to the pre-filter body 38 is wound up.

According to 6th can use the web material used here 42 preferably by a three-dimensional tangled fabric 46 or by a non-directional scrim 47 be educated. The tangled fabric 46 or the scrim 47 is made with the help of at least one plastic thread 48 , preferably using a variety of plastic threads 48 made with the threads 48 are placed undirected three-dimensional and are connected to each other at contact points, in particular by fusion connections. For example, the threads 48 be placed in a partially plastic state, so that fusion connections are automatically established in the area of the contact points.

The web material is particularly advantageous 42 made of plastic, with polypropylene being preferred. In particular, the threads mentioned above 48 consist of polypropylene.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10061839 B4 [0040]

Claims (13)

Oil removal filter (6) for separating oil from water, - With a hollow cylindrical filter body (16) through which water can flow radially, - wherein the filter body (16) has a cylindrically arranged outer filter layer (20) with mineral wool (22) and a cylindrically arranged inner filter layer (21) with a multilayer filter material (23), which is arranged radially inside the outer filter layer (20), - wherein the multi-layer filter material (23) of the inner filter layer (21) has an inner prefilter layer (24) facing away from the outer filter layer (20) and an outer main filter layer (25) facing the outer filter layer (20), - wherein a pore size in the main filter layer (25) is smaller than in the pre-filter layer (24). Oil removal filter (6) Claim 1 , characterized in that the outer filter layer (20) is oleophilic and hydrophobic. Oil removal filter (6) Claim 1 or 2 , characterized in that the mineral wool (22) of the outer filter layer (20) is oleophilic and hydrophobic. Oil removal filter (6) according to one of the preceding claims, characterized in that the mineral wool (22) of the outer filter layer (20) is made oleophilic and hydrophobic by means of a phenolic resin or by means of an epoxy binder, with which the mineral wool (22) is dimensionally stabilized. Oil removal filter (6) according to one of the preceding claims, characterized in that the main filter layer (25) is designed to be oleophilic and hydrophilic. Oil removal filter (6) according to one of the preceding claims, characterized in that the main filter layer (25) has glass fibers and is made oleophilic and hydrophilic by means of a binder, preferably by means of an acrylate binder, with which the glass fibers are stabilized. Oil removal filter (6) according to one of the preceding claims, characterized in that the prefilter layer (24) is designed to be oleophilic and hydrophobic. Oil removal filter (6) according to one of the preceding claims, characterized in that the prefilter layer (24) has cellulose fibers and is made oleophilic and hydrophobic by means of a phenolic resin or by means of an epoxy resin, with which the cellulose fibers are stabilized. Oil removal filter (6) according to one of the preceding claims, characterized in - that the main filter layer (25) is designed to be oleophilic and hydrophilic, and - that the prefilter layer (24) is designed to be oleophilic and hydrophobic. Oil removal filter (6) according to one of the preceding claims, characterized in - that the outer filter layer (20) is oleophilic and hydrophobic, - that the main filter layer (25) is oleophilic and hydrophilic, and - that the prefilter layer (24) is oleophilic and is designed to be hydrophobic. Oil removal filter (6) according to one of the preceding claims, characterized in - that the main filter layer (25) has a glass fiber layer or is formed by a glass fiber layer, - that the pre-filter layer (24) has a cellulose layer or is formed by a cellulose layer, - that the The cellulose layer of the pre-filter layer (24) rests directly on the glass fiber layer of the main filter layer (25). Oil removal filter (6) Claim 11 , characterized in - that the glass fibers of the glass fiber layer of the main filter layer (25) are stabilized by means of an acrylate binder, - that the cellulose fibers of the cellulose fiber layer of the prefilter layer (24) are stabilized by means of a phenolic resin or an epoxy resin. Oil removal device (1) for separating oil from water, - with a filter housing (2), - with a raw water inlet (3) through which water contaminated with oil can be fed, - with a pure water outlet (4) through which water from which oil has been removed can be drained off, - with an oil outlet (5) through which oil separated from the water can be drained away, - With a de-oiling filter (6) according to one of the preceding claims, which is arranged in the filter housing (2) and therein a raw water inlet (3) fluidly connected to the raw water inlet (7) of a clean room (8) fluidly connected to the pure water outlet (4) separates.

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