Filter element and filter cartridge for removing impurities from a turbid gas stream to be filtered

Abstract

The present invention relates to a filter element and a filter cartridge for removing impurities from a turbid air flow to be filtered, the filter cartridge comprising a cylindrical filter element made of filter material, a filter insert inserted in the filter element, an inner space formed between the filter element and the filter insert, the filter material being designed so that the filter material can be cleaned when a compressed air flow opposite to the flow direction of the turbid air flow is applied, and a base having a guide device with a surface designed for guiding the compressed air flow, wherein the base has a distal region which cooperates with an end piece separated from the filter element and can be mounted on an external housing for guiding the compressed air flow.

Description

[0001] This application is a divisional application of application number 201980013109X, and the invention name is "Split flow guide device, centering device, filter unit, assembly method and cleaning method of filter unit". Technical Field

[0002] The invention relates to a filter element for removing impurities, such as dust, from a turbid gas flow. It comprises a cylindrical filter element, for example made of filter material or of airtight material, and a filter insert made of filter material inserted in the filter element, and also comprises an annular inner space formed between the filter element and the filter insert, wherein the filter material is designed to be cleaned when a compressed air flow in the opposite direction to the turbid gas flow is applied, and a flow guide substrate having a surface for guiding the compressed air flow. The filter element is also called an outer bag. The filter insert is also called an inner bag.

[0003] Furthermore, the invention relates to a kit comprising an end piece and a filter element for removing impurities from a turbid gas stream to be filtered. The invention also relates to a filter unit for removing impurities from a turbid gas stream to be filtered, comprising a housing in which at least one filter element is mounted, and an end piece fixed to the housing, an axial end face of the end piece being located facing a first axial end face of the filter element base. Furthermore, the invention relates to a method for cleaning a filter element preferably in a filter unit, wherein a compressed air stream is ejected from a nozzle of a compressed air tank of the filter unit and then flows to a flow guide comprising a base and an end piece, and is diffused by the outer shape of the flow guide so that it can cover at least 80% of the filter material of the filter element. Background Art

[0004] From the prior art, filter elements are already known. For example, U.S. Pat. No. 5,972,059 discloses an air filter comprising a cylindrical air filter element, which comprises a substrate having an opening, and the substrate comprises an upper element having an opening. The opening of the upper element is arranged opposite to one end of the cylindrical air filter element, the opening of the substrate is arranged opposite to the other end of the cylindrical air filter element, and the cylindrical air filter element further comprises an elongated conical filter element having a head portion, and the longitudinal outer wall of the conical filter element extends opposite to the main part of the longitudinal inner wall of the cylindrical filter element. The opening of the base body is arranged opposite to the base portion of the conical filter element and includes means for fixing the head portion of the conical filter element to the inner wall of the cylindrical filter element, the air to be filtered is guided through the base portion to the inner region of the conical filter element, wherein the air flows through the wall of the conical filter element into the space between the outer wall of the conical filter element and the inner wall of the conical filter element, wherein the air to be cleaned also flows through the wall of the cylindrical filter element into the space between the outer wall of the conical filter element and the inner wall of the cylindrical filter element, and the air in this space is the clean air flowing out through the opening of the upper element. Thus, a filter element is described, wherein the air to be cleaned is guided inwardly through the outer wall of the cylindrical element and outwardly through the inner wall of the conical filter element into the inner space between the conical filter element and the cylindrical filter element, thus cleaning the air flow.

[0005] The prior art has always had the disadvantage that the filter element must be replaced frequently, so that a new flow guide must be produced each time the filter element is replaced, even if the service life of the flow guide is longer than the service life of the filter material of the filter element and therefore does not need to be replaced. In addition, there are some filter elements in which the flow guide protrudes from the filter element in the axial direction, which hinders and prevents the replacement of the filter element, because the filter unit housing in which the filter element is installed is usually of as compact a design as possible, so the part protruding from the filter element requires a larger housing opening when the filter element is replaced. Summary of the invention

[0006] The object of the present invention is therefore to avoid or at least reduce the disadvantages of the prior art. In particular, a filter element which can be manufactured at low cost, is universal and can be used in a compact housing is developed. In addition, the object of the present invention is to provide a filter element with improved filtering performance.

[0007] According to the invention, this object is achieved by a general arrangement in which the base body has a distal region cooperating with an end piece separated from the filter element and mounted on the outer housing for guiding the compressed air flow.

[0008] In other words, the present invention relates to a filter element for removing impurities from a turbid air flow. It comprises a cylindrical filter element, for example made of a filter material, a filter insert made of the filter material inserted in the filter element, and an inner space between the filter element and the filter insert, wherein the filter material is designed to be cleaned when a compressed air flow in the opposite direction to the turbid air flow is applied, wherein a flow guide part is provided, which is completed by another flow guide part that is not part of the filter element. This means that the flow guide part of the filter element is not complete. At the same time, this means that the flow guide part of the filter element is configured and arranged to guide the compressed air flow (only) by interaction with another flow guide part, that is, to complete the function of guiding the compressed air flow.

[0009] The base body is the part of the flow guide device that is fixed to the filter element; therefore, it is a part of the filter element. The end piece is another part of the flow guide device that is not fixed to the filter element, but to the outer housing. The base body and the end piece together fulfill the function of the flow guide device for guiding the compressed air flow.

[0010] This provides the advantage that the split design of the flow guide device enables the filter element to be replaced with one part (i.e. the end piece) remaining in the housing. In this way, the filter element can be pulled out, for example, in the horizontal direction (e.g. via a fixing rail), as the part of the flow guide device extending from the filter element, i.e. the end piece, remains in the housing, so that the filter element and the axial end end are flush.

[0011] Furthermore, it may be advantageous if only the base body of the flow-guiding device has to be replaced, while the end pieces can be reused, which has a favorable effect on the production costs of the (replacement) filter element and facilitates the replacement of the filter element.

[0012] Advantageous embodiments are set forth in the subclaims and are described in detail below.

[0013] Preferably, the filter material of the filter element and / or the filter insert with pleats formed therein comprises beads, for example (hot melt) glue beads, separating the pleats from one another, wherein the beads fill the pleats to a depth of less than 80%, preferably less than 70%, more preferably less than 60%. As a result, less filter area is covered by the glue beads, thereby improving the filter performance.

[0014] Preferably, the filter material of the filter element and / or the filter insert is passed by the dirty air flow from a first side of the filter material to a second side of the filter material, wherein the beads are arranged on the first side of the filter material and / or on the second side of the filter material. According to a preferred embodiment, the beads are arranged on both sides of the filter material of the filter element. According to a preferred embodiment, the beads are arranged on the first side of the filter material of the filter insert, i.e. the dirty side.

[0015] Preferably, the pleats have walls and pleats connecting adjacent walls, wherein the beads extend over the pleats or the pleats are uncovered. According to a preferred embodiment, the beads of filter material of the filter element extend over the pleats. According to a preferred embodiment, the beads of filter material of the filter insert leave the pleats uncovered, i.e. do not extend over the pleats.

[0016] Preferably, the beads are spaced apart from each other in the axial direction by a predetermined distance, wherein the distance is greater than the depth of the pleats. According to a preferred embodiment, the axial spacing of the beads is between 1.5 and 2.5 inches, more preferably about 2 inches. According to a preferred embodiment, the depth of the pleats is between 1.0 and 2.0 inches, more preferably about 1.5 inches.

[0017] In addition, the present invention also relates to a centering device for a filter element, which includes a filter element made of filter material and a filter insert made of filter material inserted in the filter element, including a first centering part with a radially inward gradient for centering the centering device to align the filter element and / or a second centering part with a radially inward gradient for centering the centering device to align the filter insert.

[0018] In addition, the present invention also relates to a filter unit, comprising a housing, at least one filter element arranged in the housing, an end piece that completes the distal area of ​​the base body to form a flow guide device, and a centering device for centering the filter insert on the filter element, the end piece and / or the centering device being fixed to the housing, wherein the axial end face of the end piece is located at a first axial end face facing the filter element base body.

[0019] Furthermore, the invention relates to a method for assembling a filter unit, wherein a filter cartridge comprising a filter element and a filter insert is pressed axially against a centering device so that the inner peripheral surface of the filter element is guided by a first centering portion to a position centered on the centering device and / or so that the inner peripheral surface of the filter insert is guided by a second centering portion to a position centered on the centering device, and wherein the filter cartridge is fixed to a housing and the filter element and / or the filter insert is centered. According to a preferred embodiment, a seal is provided between the housing and the filter element and / or between the housing and the filter insert.

[0020] In addition, the present invention also relates to a method for cleaning a filter element, preferably in a filter unit, a compressed air flow is ejected from a nozzle of a compressed air tank, then approaches a flow guide device including a base and an end piece, and is diffused by the outer shape of the flow guide device and passes through the filter material of the filter element.

[0021] Furthermore, it is useful when the surface of the substrate, in particular the radially outer surface, is formed and positioned so that it transforms smoothly and / or infinitely and / or conforming to a slope and / or conforming to a curvature into the outer surface of the end piece, in particular the radially outer surface. In this case, conforming to the slope means that at the transition point of the (outer) surface, the slope of the substrate surface and the slope of the outer surface of the end piece are the same. In this case, conforming to the curvature means that the curvature of the substrate surface and the curvature of the outer surface of the end piece are the same at the transition point (of the (outer) surface). This enables the flow of the compressed gas flow to be guided along the surface with minimal energy losses.

[0022] Furthermore, it is more advantageous when the transition from the surface of the base body to the outer surface of the end piece is such that the flow direction of the compressed air flow during the cleaning process is adjacent to the total surface of the base body and the end piece, so that at least 80%, preferably more than 90%, further preferably more than 95%, and particularly preferably 100% of the filter material of the filter element is reached during the cleaning. Therefore, the base body and the end piece are adjacent so that their surfaces form a total surface along which the flow of the compressed air flow is guided and thus the flow range is expanded so that the flow covers the filter material.

[0023] It is further preferred when (only) the base body, i.e. only a part of the flow guide device, is fastened to the filter material, for example to the filter insert. Conversely, this means that at least a part of the flow guide device, i.e. the end piece, is not fastened to the filter material and / or the filter element. This helps to reduce the parts that need to be replaced when replacing the filter element.

[0024] Another function fulfilled by the flow guide is grounding the filter element to the housing. This is necessary and relevant in terms of safety, especially when using antistatic filter materials, for explosive dusts. For this purpose, the filter material is conductively connected to one half of the cover of the filter element, i.e. to the base body. The housing is conductively connected to the cover head / end piece located in the filter housing. When the filter element is installed, an electrical contact is made between the two cover parts, i.e. between the base body and the end piece, for example by means of a spring or a positive fit, and voltage can flow from the filter element into the housing.

[0025] By the same mechanism, when installing the filter element and connecting the cover part, the circuit can be closed to ensure that only the filter element suitable for use can be inserted.

[0026] As another option, RFID technology can also be used to integrate it as a transmitter and a receiver in the end and the base body of the flow-guiding device, so that the system is blocked in the event of an assembly error.

[0027] With the flow guide, grounding of the filter element can be performed via the electrical contact at the disconnection point.

[0028] It has the further advantage when conductive elements for grounding are provided in the base body (and at the end) which are designed so that grounding of the filter element relative to the housing can be performed. In particular, this is advantageous when the conductive elements are in the form of resilient contact electrodes. As an alternative, form-fitting elements such as plugs or profiles on the contact surface with the end piece can also be provided.

[0029] Furthermore, it is more useful if the base body comprises a receiver or a transmitter with RFID technology for checking the fitted filter element and / or checking the positioning of the filter element. This helps to easily check whether the fitted filter element has been inserted into the filter unit and / or whether the filter element is correctly positioned. The receiver or the transmitter of the base body is designed to communicate with a corresponding transmitter or receiver in the end piece. Alternatively, the check can also be performed by closing the circuit and / or by mechanical form fit when the base body is pressed against the end piece, or when the filter element is pressed against the filter housing.

[0030] According to a preferred embodiment, the filter insert can be aligned to the center position of the filter element during assembly. The filter element is pressed onto a centering device, which includes a first centering portion for aligning the filter element to the centering device and a second centering portion for aligning the filter element insert to the centering device. It is useful when the end piece is arranged coaxially with the centering device. It is useful when the end piece is fixed to the centering device. The first centering portion can form a protrusion protruding in the axial direction. The first centering portion protrudes in the first axial direction. The first centering portion includes a tapered radial outer circumferential surface. The first centering portion tapers radially inwardly in the first axial direction. The second centering portion can form a protrusion protruding in the axial direction. The second centering portion protrudes in the first axial direction. The second centering portion includes a tapered radial outer circumferential surface. The second centering portion tapers radially inwardly in the first axial direction. During assembly, when the first filter element is pressed onto the centering device, the radial inner circumferential surface of the filter element is guided by the first centering portion to a position centered on the centering device, i.e., centered on the position of the end piece. During assembly, when the first filter element is pressed onto the centering device, the radially inner circumferential surface of the filter insert is guided by the second centering portion to a position centered on the centering device, ie, centered on the position of the end piece.

[0031] The guide device takes on additional functions via the contact surface between the end piece and the base body, such as grounding the filter element and the filter cartridge relative to the filter housing, checking the position of the filter cartridge in the housing, protecting and checking whether the correct filter cartridge is in the filter housing, for example mechanically and / or electrically via RFID technology.

[0032] It is further advantageous that the peripheral edge of the first axial end face (at the first axial end) of the base body is located (preferably completely located) in the plane in which the axial end face of the filter element is arranged. In this way, it is advantageously ensured that the filter element terminates / ends flush with the axial end face of the filter element in the axial direction, so that no part of the filter element protrudes from the filter element in the axial direction.

[0033] Furthermore, it is useful when the outer peripheral edge of the base body is rounded, which helps to evenly expand the flow rate in the radial direction.

[0034] Furthermore, it is particularly advantageous when the base body is a cone or a parabola, so that the flow rate of the compressed air stream axially impacting the base body along its surface can be enlarged with particularly small energy losses.

[0035] In addition, it is advantageous when the outer diameter of the substrate increases from the first axial end face of the substrate to the second axial end face opposite to the first axial end face of the substrate, so that the compressed air flow can be advantageously guided to flow radially outward along the surface of the substrate, thereby widening the compressed air flow.

[0036] Particularly preferably, the inclination of the outer diameter of the matrix decreases from the first axial end face to the second axial end face of the matrix. In this way, the compressed air flow is more strongly widened at the beginning and is more steadily guided outwards with the increase of the axial length, i.e., the intensity is reduced.

[0037] Furthermore, it is advantageous if the base body is in the form of a hollow wall or a solid body, ie the form of the base body surface is particularly important.

[0038] It is also useful when the first axial end face of the base body is flat or concave, ie the base body does not protrude beyond the filter element in the axial direction but is flush with the axial end face of the filter element or bulges inwardly.

[0039] The object of the present invention is also achieved by a kit, which includes an end piece and a filter element according to the present invention for removing impurities from a turbid gas flow to be filtered, wherein the filter element includes a cylindrical filter element made of filter material, a filter insert made of filter material is inserted into the filter element, and an internal space is formed between the filter element and the filter insert, wherein the filter material is designed to be cleaned when a compressed air flow in the opposite direction to the turbid gas flow is applied, and includes a substrate, which interacts with the end piece to form a guide device for guiding the compressed air flow.

[0040] In addition, the object of the present invention is also achieved by a filter unit for removing impurities from a turbid gas flow to be filtered, which includes a housing in which at least one filter element according to the present invention is arranged, and includes an end piece fixed to the housing, wherein the axial end face of the end piece is located at a first axial end face facing the filter element base.

[0041] Preferably, the filter unit has a compressed air tank which comprises at least one nozzle and is designed to eject a compressed air flow to act on the filter material.

[0042] Furthermore, it is also advantageous when the outer peripheral edge of the first axial end face of the base body is in the shape of a circular ring, the outer diameter of which corresponds to the outer diameter of the outer peripheral edge of the axial end face of the end piece.

[0043] Particularly preferably, the end piece presents a parabolic shape rotated around the longitudinal axis. Particularly preferably, the end piece is the upper part of the parabola body, the base body is the lower part of the parabola body, and the end piece and the base body together present a parabolic shape rotated around the longitudinal axis.

[0044] In addition, it is preferred that the first axial end face of the base body is adjacent to the axial end face of the end piece. In this way, a connecting body constituting the flow guiding device is formed.

[0045] Furthermore, it is advantageous when the end piece and the base body are arranged in such a way that the outer shape of the end piece is transformed into the outer shape of the base body.

[0046] The object of the present invention is also achieved by a method for cleaning a filter element according to the present invention, preferably in the filter unit, a compressed air flow is ejected from a nozzle of a compressed air tank of the filter unit, then flows to a flow guide device including a base body and an end piece, and is diffused by the external shape of the flow guide device so that it covers at least 80%, preferably more than 90%, further preferably more than 95%, and particularly preferably 100% of the filter material of the filter element.

[0047] According to another aspect of the invention, which is independent of the above-described embodiment but can preferably also be combined with the features of the above-described embodiment, the invention relates to a filter element for removing impurities from a turbid gas flow to be filtered, comprising a cylindrical filter element made of filter material, into which a filter insert, for example made of filter material or of an airtight material, is inserted, wherein between the filter element and the filter insert, i.e. inside the filter element, a preferably annular inner space is formed, the filter material is designed so that it can be cleaned when a compressed air flow opposite to the flow direction of the turbid gas flow is applied, the filter element having a cover in the form of a flow guide, the outer shape of the cover being designed so that the compressed air flow can be diffused through the cover, so that the entire filter material of the filter element is covered by the compressed air flow and the energy losses generated are kept at a low level. This provides the advantage that, on the one hand, the compressed air flow is guided so that the entire filter material or at least the entire filter material of the cylindrical filter element is covered, and not only the lower part of the filter element is covered by the compressed air flow. On the other hand, a suitable design of the outer shape of the cover helps to achieve that the energy of the compressed air flow is only reduced to a minimum, i.e. as little as possible, during the diffusion process. Therefore, in the filter element according to the present invention, the cleaning effect can be improved to make the cleaning of the filter element more gentle and reduce the frequency of cleaning, and compressed air can be saved, thereby greatly reducing the cleaning cost and extending the service life of the filter element.

[0048] Furthermore, it is useful when the energy loss generated is less than 40%, preferably less than 20%, and more preferably less than 10%.

[0049] In the following, the direction parallel to the central axis of the filter element (and, the filter element and the filter insert and the cover) is referred to as the axial direction. In the following, the direction which is the axial direction and in which the compressed air flow flows is referred to as the first axial direction. The direction opposite to the first axial direction will be referred to as the second axial direction. Therefore, the turbid air flow flows into the filter element in the second axial direction, while the compressed air flow flows into the filter element in the first axial direction.

[0050] Here, one axial end of the filter element (as well as the filter element, filter insert and cover) facing the first axial direction is called the first axial end, and the other axial end of the filter element (as well as the filter element, filter insert and cover) facing the second axial direction is called the second axial end.

[0051] It is further advantageous when the cover is arranged at least partially in the inner space of the filter element. This helps to prevent the axial length of the filter element from being increased by the cover.

[0052] Furthermore, it is advantageous if the interior space of the filter element has an annular cross section and is at least partially constant when viewed along the axial length of the filter insert and / or the filter element. On the one hand, the volume of the interior space is thereby minimized compared to an interior space of a non-constant annular cross section, such as is obtained with a conical filter insert, so that it is easier to generate a higher pressure in the interior space of the filter element. At the same time, the filter area of ​​the filter element can be increased.

[0053] Furthermore, it is advantageous if the inner space has a constant annular cross section along the entire axial length of the filter insert and / or the filter element. In this way, since the cross section remains constant, the compressed air flow does not need to be expanded further over the axial length of the filter insert, thereby preventing additional energy losses of the compressed air flow, thus further improving the cleaning result.

[0054] An advantage of a suitable exemplary embodiment is that the filter insert has a cylindrical outer diameter. On the one hand, this can achieve the above advantages, and on the other hand, this greatly simplifies the structure of the filter element.

[0055] Furthermore, when the outer shape of the cover is convex, it is preferably strictly convex. This means that the cover bulges toward the compressed air flow. This also means that the cover bulges outwards when viewed from the filter insert. This enables a particularly suitable air flow bypass when the compressed air flow hits the outer shape of the cover. In particular, this configuration is preferred with regard to minimizing energy losses and with regard to expanding the compressed air flow to the diameter required for the inner space.

[0056] It is also advantageous when the cover is arranged at an axial end of the filter insert. It is also particularly preferred when the cover is fixed to the filter insert, in particular to an axial end face of the filter insert. It is particularly preferred that the cross section of the cover is converted into the cross section of the filter insert, i.e. the outer diameter of the cover corresponds to the outer diameter of the filter insert at the position where the cover is adjacent to the filter insert. This also means that at the second axial end of the cover, the outer diameter of the cover corresponds to the outer diameter of the filter insert at the first axial end of the filter insert. In this way, the compressed air flow advantageously flows through the cover and then through the outside of the filter insert.

[0057] One suitable exemplary embodiment is therefore advantageous in that the outer diameter of the end of the cover facing the filter insert, i.e. the outer diameter at the second axial end of the cover, substantially corresponds to the outer diameter of the end of the filter insert facing the cover, i.e. the outer diameter at the first axial end of the filter insert. Thus, the outer shape of the cover is transferred to the filter insert almost "seamlessly".

[0058] Furthermore, it is advantageous if the cover and the filter cartridge and / or the filter element and / or the filter insert are arranged coaxially, so that a uniform flow of the compressed air flow can be achieved.

[0059] It is further preferred that the cover is formed from a solid material or is in the form of a sleeve / shell, for example depending on the requirements regarding weight or rigidity.

[0060] In particular, it is advantageous when the outer shape of the cap follows a parabolic function and / or a root function. This means that the outer contour of the cap follows a root function from a first axial end of the cap, at which the cap is maximally curved, to its second axial end, which is axially opposite to the first axial end. This also means that the cap is rotationally symmetrical, the cap being formed by the rotation of a parabola about its longitudinal axis. This therefore means that each longitudinal cross section of the cap is in the form of a parabola. Furthermore, this means that each cross section of the cap is circular.

[0061] Furthermore, the cover is advantageously designed such that the slope of the parabola followed by the outer shape of the cover decreases in the axial direction starting from the first axial end. This means that the outer diameter of the cover increases in the axial direction from the first axial end where the cover is most curved to its other axial end, the second axial end, but the increase in its outer diameter is less intense as the axial length increases.

[0062] It can also be said that the outer shape of the cover is configured so that its shape is equivalent to the nose of a supersonic aircraft. Therefore, the cover has an egg-shaped tip. In other words, the first axial end of the cover is blunt and not pointed.

[0063] Furthermore, it is suitable when the outer shape of the cover follows the function f(x)=x1 / 2 (in other words: x raised to the power of 2). When the cover is configured with the above outer shape, particularly favorable ambient flow conditions are provided, which are optimized in particular for incident flows with high velocities.

[0064] It has a further advantage that when the outer shape of the cover is adapted to the outer diameter of the inner space of the filter element, the compressed air flow is diffused to the filter material of the filter element. Therefore, the compressed air flow flows through the filter material of the filter element from the inside to the outside, that is, against the direction of the dirty air flow, so that the filter material is cleaned.

[0065] More preferably, the axial length of the cover is 0.5 to 2 times the outer diameter of the inner space of the filter element. Further preferably, the axial length of the cover is 1.5 to 1.0 times the outer diameter of the inner space of the filter element. In this way, a suitable compromise is achieved between the widening of the compressed air flow and the energy loss when the compressed air flow hits the cover.

[0066] In addition, the outer shape of the cover is preferably designed to be approached by a high-speed airflow, that is, the outer shape of the cover is specially configured so that when it contacts, i.e., is approached by a high-speed to supersonic airflow, the airflow achieves the desired diffusion, while the energy loss thereby generated is minimized. Such an outer shape has been used in other applications, such as in the field of aircraft noses.

[0067] It is further advantageous to arrange an annular component at the second axial end of the filter element for connecting the second axial end of the filter element to the second axial end of the filter insert. In this way, it is possible to prevent the filtered turbid gas from the inner space from mixing with the unfiltered turbid gas outside the filter element. At the same time, stability is provided to the filter element.

[0068] The annular component is configured to be airtight, whereby it brings additional stability to the filter element, since stronger materials can be used. In particular, the filter insert and the filter element are inserted into a disk which is filled with molding material (eg resin) and connected in a sealed manner.

[0069] Furthermore, it is suitable when a hole is provided at the first axial end of the filter element, from which the purified air can advantageously flow out. In other words, the first axial end is the end of the filter element from which the filtered dirty air flow, i.e. the clean air flow, flows out. The second axial end of the filter element is closed, i.e. the air outside the filter element cannot mix with the air inside the filter element. The air can only enter the inner space of the filter element through the filter material.

[0070] It is particularly preferred that the hole has a circular design. A preferred embodiment is that the hole is converted into the inner space of the filter cartridge between the filter insert and the filter element. In the axial direction starting from the first axial end of the filter cartridge to the first axial end of the cover, the filter cartridge thus has a circular cross-section. The cover and the filter insert connected to the cover in the axial direction transfer the annular cross-section to the inner space of the filter cartridge from the first axial end of the cover to the second axial end of the filter cartridge. Therefore, the cover is preferably configured so that the compressed air flow is smoothly guided, i.e. with minimal energy losses, from the circular cross-section to the annular cross-section, i.e. widened along the outer shape of the cover.

[0071] During the filtering operation of the filter element, the turbid air flow to be filtered passes through the filter material, so that the air flow passes through the filter element from its second axial end to its first axial end. This means that the turbid air flow passes through the filter element, in particular through the filter material of the filter element, from the outside to the inside into the inner area. In addition, this means that when the filter insert is composed of filter material, the turbid air flow passes through the filter insert, in particular through the filter material of the filter insert, from the inside to the outside into the inner area. However, it is also possible to configure the filter insert as a non-ventilated / non-flowing material so that it acts as a displacer, thereby improving the cleaning effect.

[0072] Furthermore, in a preferred exemplary embodiment, the filter element is designed such that the dirty gas flow flows out of the filter material as a clean gas flow. This means that the entire interior of the filter element forms a clean gas chamber, which is surrounded by the filter material of the filter element and the filter material of the filter insert and contains the filtered raw gas before it flows out of the pores.

[0073] Furthermore, it is advantageous if the filter material of the filter element and / or filter insert is folded in a star shape, ie the filter element and / or filter insert has a star-shaped cross section, since it then comprises an enlarged filter surface, which has a positive influence on the filtering result.

[0074] The object of the present invention is also achieved by a filter unit for removing impurities from a turbid gas flow to be filtered, wherein the filter unit comprises a housing in which at least one filter element according to the present invention is arranged, and a compressed air tank having at least one nozzle and being designed to spray a compressed air flow onto and act on the filter material.

[0075] It is particularly advantageous if the compressed air tank is designed to spray a compressed air stream at a pressure of 4-8 bar. This helps to achieve a good cleaning result.

[0076] Therefore, according to the invention, the outer shape of the cover of the filter element is adapted to both the outer diameter of the inner space, i.e. the inner diameter of the filter element, and the distance between the nozzle and the filter element, i.e. the compressed air flow is widened by the cover, so that the entire filter material is covered by the compressed air flow and the accompanying energy loss is minimized. Therefore, the outer shape of the cover depends on both the size of the filter element, in particular the outer diameter, and the distance between the nozzle ejecting the compressed air flow and the filter element, and also on the flow rate of the compressed air flow and the energy of the compressed air flow.

[0077] Due to the increased hole angle of the free jet, the axial distance between the nozzle and the filter element can be reduced by the cover, so that the filter medium / filter material can also be cleaned at the filter element inlet, i.e. in the upper part of the filter element.

[0078] Therefore, it is particularly advantageous when the nozzle is configured to cause the compressed gas flow to be ejected from the nozzle at a high to supersonic speed. In particular, it is advantageous when the nozzle is a Laval nozzle.

[0079] Advantageously, the distance between the nozzle and the filter element in the axial direction is less than 3 times the outer diameter of the inner space of the filter element, preferably less than 2 times the outer diameter of the inner space of the filter element, and further preferably less than 1.5 times the outer diameter of the inner space of the filter element. Therefore, in this way, the construction space of the entire filter unit in the axial direction can be minimized.

[0080] Furthermore, it is advantageous when the filter element is arranged horizontally or preferably vertically. That is, the axial direction of the filter element coincides with the horizontal direction and the vertical direction / direction of gravity. In particular, when the filter element is arranged vertically, during cleaning, dust can fall downwards in the direction of gravity and cannot be deposited again on the filter element.

[0081] An advantage of an advantageous exemplary embodiment is that a plurality of filter elements are arranged in the filter unit, so that the filtering capacity of the entire filter unit is increased.

[0082] Furthermore, it is advantageous if the axial length of the filter insert is smaller than the axial length of the filter element. In other words, the filter insert is located completely within the filter element. In other words, in particular in the axial direction, it does not protrude beyond the axial length of the filter element. This also means that the filter insert has at most the same axial length as the axial length of the filter element.

[0083] The invention also relates to a method for cleaning / washing a filter element according to the invention, which is preferably arranged in a filter unit according to the invention. The method comprises the following steps: a compressed air stream is first ejected from a nozzle, then approaches a cover of the filter element and is diffused by the outer shape of the cover so that it covers the entire filter material of the filter element.

[0084] According to another aspect of the invention, which is independent of the above-described embodiment but can preferably also be combined with the features of the above-described embodiment, the invention relates to a filter element for removing impurities from a turbid gas flow to be filtered, comprising a cylindrical filter element made of filter material, in which a filter insert, for example made of filter material or airtight material, is inserted. An annular inner space is formed between the filter element and the filter insert, the filter material is designed to be cleaned when a compressed gas flow is applied against the flow direction of the turbid gas flow, and a cover in the form of a flow guide is provided for guiding the compressed gas flow, the position of the cover being designed so that it protrudes in the axial direction from the axial length of the filter element. This means that the cover protrudes from the filter element in the axial direction. This provides the advantage that the compressed gas flow can be widened to the required annular cross section, i.e. to the required inner diameter, before reaching the filter element, so that the axial distance between the compressed gas flow source and the filter element can be reduced, which has a favorable effect on the axial space required for the entire filter unit. Furthermore, by "widening earlier" in the axial direction, design freedom is apparent in terms of the outer shape of the cover, so that the compressed air flow can, for example, diffuse more slowly, i.e. more gently, which is advantageous for reducing energy losses during diffusion.

[0085] Furthermore, it is advantageous that the first axial end of the cover is located outside the filter element in the axial direction. Thus, the compressed air flow can advantageously be expanded to the desired diameter when it reaches the filter element, so that a part of the filter element at the first axial end, i.e. at the end facing the compressed air flow, can also be covered by the compressed air flow and can be fully cleaned.

[0086] It is further advantageous when the outer diameter of the cover increases from a first axial end of the cover to a second axial end opposite the first axial end of the cover. This means that, when viewed along the axial length of the cover, the outer diameter of the cover is smallest at the first axial end and largest at the second axial end. Since the compressed air flow first impacts the cover at the first axial end of the cover, the compressed air flow is particularly directed radially outwards and thus widened by the extended outer shape of the cover. Therefore, the slope or curvature of the widening of the outer diameter helps to control the direction and flow path in which the compressed air flow is directed.

[0087] It is further preferred that the second axial end of the cover is arranged in the filter element in the axial direction. Therefore, it is advantageously ensured that the compressed airflow flowing along the outer shape of the cover flows into the inner space of the filter element and covers the wall of the filter element from there.

[0088] In addition, an advantageous exemplary embodiment is that the cover comprises two parts, wherein the first part of the cover is arranged outside the filter element in the axial direction, and the second part of the cover is arranged inside the filter element. That is to say, the first part of the cover is the part of the cover that protrudes from the filter element in the axial direction, and the second part of the cover is the part of the cover that is arranged inside the filter element in the axial direction, i.e., is located at the same axial height as the filter element. In other words, the cover is partly located inside the internal space of the filter element and partly located outside the internal space of the filter element. In this way, the compressed gas flow can be particularly advantageously directed to the wall of the filter element, i.e., to the filter material of the filter element and the filter material of the filter insert. At the same time, the distance between the compressed gas source and the filter element can be greatly reduced compared to a filter element in which the cover is completely arranged inside the filter element, i.e., completely in the internal space.

[0089] It is also advantageous if the first cover part and the second cover part are integrally formed, i.e. one-piece. This, on the one hand, reduces the manufacturing costs of the cover and, on the other hand, facilitates the assembly method, since the two parts do not need to be aligned with each other and assembled together. Furthermore, in this way, a particularly smooth, i.e. seamless / infinite, transition between the two parts can be achieved.

[0090] It is also possible to form the first cover part and the second cover part separately, i.e. as separate components. This allows the two parts to be mounted separately from each other, for example one part is mounted on a component fixed to the housing and the other part is mounted on the filter element, so that a complete cover is only formed when the filter element is inserted into the filter unit. This makes it easier to replace the filter element.

[0091] In addition, it is suitable when the axial length of the first axial portion of the cover is 0.5 to 1.0 times the inner diameter of the filter element. In this way, particularly favorable flow guiding performance can be achieved, especially reducing the energy loss of the compressed air flow, because the compressed air flow can be diffused relatively smoothly. In addition, the axial protrusion of the filter element is thus maintained at an appropriate size, so that replacement of the filter element is still possible.

[0092] Furthermore, an advantageous exemplary embodiment has the advantage that the first part of the cover has a greater axial length than the second part of the cover. This means that, in terms of axial extension, a greater part of the cover is located outside the filter element. In particular in filter elements with a large inner diameter, this contributes to an optimized cleaning result.

[0093] Furthermore, it is advantageous if the cover is arranged completely outside the filter element, i.e. not axially inside the filter element and therefore not at the same axial height as the filter element. In this way, the entire length of the filter element can be advantageously cleaned, since the compressed air flow has already expanded to the diameter of the filter element when entering the filter element.

[0094] However, in another embodiment, it is also possible that the first part of the cover has a smaller axial length than the second part of the cover. This means that, relative to the axial extension, a larger part of the cover is located in the filter element. In particular in filter elements with a relatively small axial extension, the cleaning result can be improved thereby.

[0095] The object of the present invention can also be achieved by a filter unit for removing impurities from a turbid gas flow to be filtered, the filter unit comprising a housing in which at least one filter element is arranged, and comprising a compressed air tank, the compressed air tank comprising at least one nozzle and being designed to be able to eject a compressed air flow from the nozzle to act on the filter material. In the filter unit according to the present invention, preferably a plurality of filter elements according to the present invention are arranged therein, and compressed air flows can be applied to them through respective nozzles arranged coaxially with the filter element but spaced apart in the axial direction to clean the filter material. By inserting a cover into the filter element, the distance between the nozzle and the filter element can be shortened, because the compressed air flow discharged from the nozzle in the form of a free jet with an aperture angle of about 12° is further widened by the cover. This helps to widen the filter material of the filter element, even if the distance is reduced, and the inner diameter of the filter element can be reached.

[0096] In addition, the distance between the filter element and the nozzle is preferably less than 2.0 times, preferably less than 1.8 times, further preferably less than 1.5 times, more preferably less than 1.0 times, and even more preferably less than 0.5 times the inner diameter of the filter element. In this way, the filter unit can be configured particularly compactly in the axial direction.

[0097] Furthermore, it is advantageous when the outer shape of the cover is adapted both to the distance between the cover and the nozzle and to the inner diameter of the filter element, so that the compressed air flow is widened and the filter material of the filter element is covered by the compressed air flow. Thus, by appropriately selecting the outer shape of the cover, the energy loss of the compressed air flow when it impinges on the cover can be reduced, preferably minimized.

[0098] The object of the present invention can also be achieved by a method for cleaning the above-mentioned filter element, preferably in such a filter unit, the compressed air flow is ejected from the nozzle, then approaches the cover of the filter element, and is widened by the outer shape of the cover so that it covers the filter material of the entire filter element. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] The present invention will be described below by means of the accompanying drawings, in which:

[0100] Figure 1 is a longitudinal cross-sectional view of a filter element in the first embodiment. Embodiment 1 does not make any requirements. It includes a conical filter insert, a cylindrical filter element and a flow guide device located in the filter element,

[0101] Figure 2 is a longitudinal cross-sectional view of a filter element in the second embodiment, which is not required in this embodiment.

[0102] Figure 3 is a longitudinal cross-sectional view of a filter element in the third embodiment, wherein the flow guide device is partially located outside the filter element and partially located inside the filter element.

[0103] Figure 4 is a longitudinal cross-sectional view of a filter element in a fourth embodiment, which embodiment is not required, comprising a cylindrical filter element and a cylindrical filter insert,

[0104] Figure 5 is a longitudinal cross-sectional view of a filter element in the fifth embodiment, wherein the flow guide device is completely located outside the filter element,

[0105] Figure 6 is a longitudinal cross-sectional view of a filter element in a sixth embodiment, comprising a cylindrical filter element and a cylindrical filter insert, the filter insert being made of an airtight material as a displacement body,

[0106] Figure 7is a longitudinal cross-sectional view of a filter element in the seventh embodiment, which is not required in this embodiment.

[0107] Figure 8 is a longitudinal cross-sectional view of a filter element in the eighth embodiment, wherein the flow guide device is partially located outside the filter element and partially located inside the filter element.

[0108] Fig. 9 is a cross-section of a filter element, including a conical filter insert.

[0109] Fig.10 is a cross-sectional view of a filter element cut axially, comprising a cylindrical filter insert made of filter material,

[0110] Fig.11a is a longitudinal cross-sectional view of a split flow guide device.

[0111] Fig.11b is a longitudinal cross-sectional view of a flow guide device.

[0112] Fig.12 This is a cross-sectional view of a filter element cut in a flow guide.

[0113] Fig.13 is a longitudinal sectional view of a filter unit according to the present invention,

[0114] Fig.14 is a longitudinal sectional view of a filter unit in the second embodiment,

[0115] Fig.15a and 15b is a diagram of the pleats of filter material separated by beads.

[0116] Fig.16 and 17 Filter material showing filter insert separated by beads,

[0117] Fig.18 This is a perspective view of the filter element.

[0118] Fig.19 and 20 shows a perspective view of a centering device, and

[0119] Figures 21 to 24 Shows one method of assembling a filter unit.

[0120] The accompanying drawings are only schematic and are only used to understand the present invention. The same elements have the same reference symbols. The features of the various exemplary embodiments are interchangeable. DETAILED DESCRIPTION

[0121] Figure 1A filter element 1 for removing impurities from a turbid gas flow is shown. The filter element 1 comprises a cylindrical filter element 2 made of filter material, also referred to as an outer bag. A filter insert 3 is inserted into the cylindrical filter element 2. The filter insert 3 is also referred to as an inner bag. The filter insert 3 is made of filter material. The filter element 2 and the filter insert 3 are arranged coaxially with each other. Thus, an inner space 4 is formed in the filter element 1, which inner space is annular between the filter element 2 and the filter insert 3. The filter material of the filter element 2 and the filter insert 3 is designed so that it can be cleaned when a compressed air flow is applied in the opposite direction to the turbid gas flow. The filter element 1 comprises a cover 6 in the form of a flow guide 5, the outer shape of which is designed to widen the compressed gas flow. Thus, the filter material can be completely covered by the compressed gas flow and the energy loss caused thereby is minimized. The filter element 2 has an arc-shaped cross section. The filter insert 3 has an arc-shaped cross section.

[0122] exist Figure 1 In the first embodiment, the cover 6 is completely located in the filter element 1. The cover 6 is fixed to the filter insert 3. The cover 6 has a parabolic cross section, so the cover 6 is formed by a parabola rotating around its own axis.

[0123] At one end of the filter element 1, i.e., the lower end in the figure, a filter bottom / ring component 7 is arranged between the filter element 2 and the filter insert 3, for connecting the filter element 2 and the filter insert 3. The direction pointing from top to bottom in the figure is referred to as the first axis direction 8 below, and the direction opposite to the first axis direction is referred to as the second axis direction 9. The filter bottom / ring component 7 is airtight, so that the dirty air flow outside the filter element 1 can flow from the outside to the inside through the filter material of the filter element 2 or flow from an inner area 10 located radially inside the filter insert 3 to the outside through the filter material of the filter insert 3 into the inner space 4. Figure 1 The arrows in the figure indicate the direction of flow of the turbid air flow.

[0124] During the filtering process of the filter element 1, the dirty air flow flows into the inner space 4 of the filter element 1. In order to clean the filter element 1, it is necessary to interrupt the dirty air flow supply and then apply a compressed air flow to the filter element material in the opposite flow direction to the filtering process, that is, a jet-like compressed air flow flows in the first axial direction 8 and hits the filter element 1, that is, from the top of the figure. The compressed air flow is guided by the cover 6 into the annular part of the inner space 4, so that the compressed air flow flows from the outside to the inside through the filter material of the filter element 2 and through the filter material of the filter insert 3, into the inner area 10, and releases particles accumulated in the filter material, such as dust. The flow path of the dirty air flow is composed of Figure 1 Then, the freed particles fall down in the direction of gravity, are collected in a dust collector (not shown), and are removed.

[0125] Figure 1 The filter insert 3 of the filter element 1 in FIG. 1 is conical. The filter insert 3 has a smaller outer diameter at its end facing the first axial direction 8, i.e. the first axial end, than at its second axial end opposite the first axial end. In the exemplary embodiment shown, the outer diameter increases linearly from the first axial end to the second axial end, but it can also increase in a non-linear manner, for example, by giving the radial outer surface of the filter insert 3 a curved configuration. A cover 6 is arranged on the first axial end of the filter insert 3.

[0126] At the contact surface between the filter insert 3 and the cover 6, the outer diameter of the cover 6 smoothly transforms into the outer diameter of the filter insert 3. This means that the outer diameter of the filter insert 3 at its first axial end corresponds to the outer diameter of the cover 6 at the end facing the second axial direction 9, i.e. the second axial end of the cover 6. The outer diameter of the cover 6 increases from the first axial end of the cover opposite the second axial end to the second axial end of the cover. In the exemplary embodiment shown, the increase in the outer diameter starts relatively strongly from the first axial end of the cover, but the increase in the outer diameter becomes less with increasing axial length of the cover 6. That is to say, the slope of the outer diameter of the cover 6 decreases in the axial direction (from the first axial end to the second axial end).

[0127] In the exemplary embodiment shown, the cover 6 is located completely within the interior space 4 of the filter insert 1, i.e. in the axial direction, the cover 6 does not extend to the end of the filter insert 1 facing the first axial direction 8, i.e. the first axial end of the filter insert 1 and thus also to the first axial end of the filter element 2. Thus, in the upper region of the filter insert 1, the interior space 4 of the filter insert 1 has a circular cross section, which is transformed into an annular cross section by the cover 6.

[0128] Figure 2 Filter 1 and Figure 1 The difference between the filter element 1 in FIG. 1 and FIG. 2 is that the cover 6 extends in the axial direction to the first axial end of the filter element 1. Therefore, the inner space 4 has an annular cross section along the entire axial length of the filter element 2 and thus the filter element 1.

[0129] Figure 3 Filter 1 and Figure 1 or Figure 2 The difference between the filter element 1 in FIG. 1 and FIG. 2 is that the cover 6 extends in the axial direction beyond the first axial end of the filter element 1. Therefore, the cover 6 protrudes in the axial direction beyond the filter element 2. The inner space 4 has an annular cross section along the entire axial length of the filter element 2 and thus the filter element 1.

[0130] exist Figure 4In the filter element 1 in FIG. 1 , the filter insert 3 has a cylindrical configuration. This means that the filter insert 3 has a constant outer diameter along its entire axial length. Thus, the interior space 4 forms an annular interior space 4 with a constant annular cross section over the axial length of the filter insert 3 . Figure 4 In the exemplary embodiment shown, the cover 6 is arranged completely within the interior space 4 of the filter insert 1, i.e. in the axial direction, the cover 6 does not extend to the first axial end of the filter insert 1 and thus also does not extend to the first axial end of the filter element 2. Therefore, in the upper region of the filter insert 1, the interior space 4 of the filter insert 1 has a circular cross section, which is transformed into an annular cross section by the cover 6.

[0131] Figure 5 Filter 1 and Figure 3 The difference between the filter element 1 in FIG. 1 and FIG. 2 is that the cover 6 is arranged completely outside the filter element 1 . Therefore, the cover 6 does not protrude into the filter element 2 in the axial direction. Figure 5 In the exemplary embodiment shown, the end of the cover 6 is flush with the axial end face of the filter element 1, that is, in the axial direction, the cover 6 is adjacent to the filter element 1. The filter bottom 7 is pan-shaped, and the filter element 2 and the filter element insert 3 are sealed and connected by a sealant.

[0132] Figure 6 Filter 1 and Figure 8 The difference between the filter element 1 and the filter element 3 is that the filter insert 3 is configured to be airtight and acts as a displacement body. Figure 6 As shown, the filter insert 3 can be in the form of a solid body, or it can be in the form of a hollow body or shell, as shown in the figure. The filter insert 3 in the form of a displacement body helps to improve the cleaning effect, because the compressed air flow can only escape through the filter element 2.

[0133] Figure 7 Filter 1 and Figure 4 The difference between the filter element 1 in FIG. 1 and FIG. 2 is that the cover 6 extends in the axial direction to the first axial end of the filter element 1. Therefore, the inner space 4 has an annular cross section along the entire axial length of the filter element 2 and thus also the filter element 1. Correspondingly, according to the outer shape of the cover 6, the inner diameter of the annular cross section increases from the first axial end of the filter cartridge 1 to the first axial end of the filter insert 3. From the first axial end of the filter insert 3 to the second axial end of the filter element 1, the annular cross section is constant.

[0134] exist Figure 8 In the filter element 1, the cover 6 is arranged such that a first portion of the cover 6, which includes a first axial end of the cover 6, protrudes from the filter element 2 in the axial direction, and a second portion of the cover 6, which includes a second axial end of the cover 6, is located inside the filter element 2. The first portion and the second portion may be separated from each other or formed integrally. This will be described in detail below.

[0135] Fig. 9 , 10 12 shows a cross-sectional view of the filter element 1. The filter element 2, the filter insert 3 and the cover 6 are arranged coaxially with each other. The filter insert 3 and the cover 6 are superimposed in the axial direction, and the filter element 2, the filter insert 3 and the cover 6 are located at the same axial height. Fig. 9 The cross section shown is cut in the axial region of the cover 6. The outer diameter of the filter element 2 is larger than the outer diameters of the filter insert 3 and the cover 6. The outer diameter of the filter insert 3 is larger than the outer diameter of the cover 6. The filter element 2 is made of a filter material which is folded in a zigzag manner, giving the filter element 2 a star-shaped cross section. The filter insert 3 is also made of a filter material which is folded in a zigzag manner, which is due to the fact that the filter element 2 has a star-shaped cross section. Fig.10 A cross section cut in an axial region of the filter insert 3 is shown. Fig.12 Also shown is a cross section of a filter element 1, which is cut in the axial region of the cover 6, but at an axial position corresponding to the Fig. 9 This reveals that the cross section of the cover 6 varies in the axial direction, while the cross section of the filter element 2 is constant over the entire axial length.

[0136] Fig.11b Schematic diagram of a cover 6. The cover 6 has a parabolic shape or a root shape. The cover 6 is rotationally symmetrical. Each longitudinal section passing through the axis of the cover 6 is identical and is parabolic in shape. The outer shape of the cover 6 increases in outer diameter from the first axial end to the second axial end. At the first axial end, the cover 6 has an egg-shaped, i.e., rounded tip. The outer shape of the cover 6 is an arc, with the largest curvature at the first axial end. From the first axial end to the second axial end of the cover 6, the curvature decreases in the axial direction. The outer shape of the cover 6 basically follows the function f(x)=x1 / 2, or a similar parabolic function. The cover 6 can be in the form of a solid body, or it can also be in the form of a hollow body, i.e., in the form of a shell. The outer shape of the cover 6 is configured so that it can diffuse the incident flow with particularly low energy loss when the incident flow flows vertically, i.e., flows in from the first axial direction 8. In particular, the outer shape of the cover 6 is optimized for incident flows in the high speed to supersonic range. At the second axial end, the cover 6 comprises a flat axial outer surface which is perpendicular to the axis of the cover 6 . Fig.13 and 14 A filter unit 11 according to the invention is shown. The filter unit 11 comprises a housing 12 in which two filter cartridges 1 are arranged. The filter cartridges 1 are arranged so that they can be inserted into the housing 12 via retaining guides (not shown). Fig.13 In the Figure 6 and Figure 8 The filter element 1 of the exemplary embodiment, Fig.14 In the Figure 8 The filter element 1 shown in the figure has a Fig.11a The split cover 6 of the exemplary embodiment. However, the present invention is not limited to including Fig.13 and 14 The filter unit 11 of the filter element 1 is shown.

[0137] The filter unit 11 comprises a compressed air tank 13, which can be selectively mounted inside or outside the housing 12. The compressed air tank 13 is designed to spray compressed gas through a nozzle 14 located above the filter element 1, preferably at a pressure of 4 to 8 bar (1 bar = 100000 Pa). The compressed air tank 13 and the nozzle 14 are connected to each other by a pipe / blowing pipe 15 for transferring compressed air. A nozzle 14 is provided for each filter element 1, which is arranged on the axis of the filter element 1 but is spaced apart in the axial direction.

[0138] The outer shape of the cover 6 is adapted to the distance between the nozzle 14 and the first axial end of the cover 6 or the first axial end of the filter element 1, and also to the size of the internal space 4, in particular, to the outer diameter of the internal space 4, that is, the inner diameter of the filter element 2, so as to guide the compressed air flow to the filter material to be cleaned.

[0139] exist Fig.14 In the exemplary embodiment shown, the cover 6 is configured so that a first portion 16 / end piece 16 protrudes from the filter element 2 in the axial direction and a second portion 17 / base 17 is located inside the filter element 2. In this way, the compressed air flow is already diffused in the axial direction, closer to the nozzle 14, so that the axial distance between the nozzle and the filter element 1 can be reduced.

[0140] The first part 16 and the second part 17 of the cover 6 are formed integrally (see Fig.11b and 13 ), or formed separately from each other (cf. Fig.11a and 14 ).

[0141] In a single configuration (see Fig.11a , Fig.14 ), the first part / end piece 16 of the cover 6 is tightly connected to the housing 12, and the second part / base 17 of the cover 6 is tightly connected to the filter element 1. In a separate configuration, the two parts 16 and 17 do not need to be connected to each other. It is sufficient when the two parts 16 and 17 are arranged adjacent to each other or there is a small gap between the two parts 16 and 17, which gap is, for example, smaller than the wall thickness of the filter element 2. Therefore, the second part 17 has a parabolic lower shape. When in Fig.14When the filter element 1 is replaced with the filter unit 11 in the housing 12 , the first part 16 of the cover 6 remains in the housing 12 .

[0142] The second part 17 of the cover 6 comprises, at its first axial end, a flat axial outer surface facing in the first axial direction 8. The (first) axial outer surface / end face is circular and has the same outer diameter as the axial outer surface / end face of the first part 16. The outer edge / outer periphery of the axial end face of the second part 17 of the cover 6 is completely in a plane located at the axial end face of the filter element 2. This means that the second part 17 of the cover 6 ends flush with the filter element 2 in the axial direction. The outer diameter of the second part 17 of the cover 6 increases from the first axial end of the second part 17 to the second axial end of the second part 17. The radial outer surface of the second part 17 is preferably configured to be slightly curved outwards or to be straight / flat.

[0143] Fig.15a and 15b Filter material is shown. The filter element 2 is made of filter material. The filter insert 3 is made of filter material. The filter material is pleated. The filter material comprises pleats 25 formed by side walls / panels 26 and pleats 27. One pleat 27 connects two adjacent side walls 26. The side wall 26 has a flat and generally rectangular shape. The pleats 25 can increase the area of ​​the filter material. The filter material comprises beads 28, such as beads of adhesive material, in particular (hot melt) glue beads, which separate the pleats 25 from each other. In use, the turbid gas flow to be filtered flows through the filter material. The turbid gas flow flows through the filter material from the first side 29 of the filter material to the second side 30 of the filter material. The first side 29 is also called the dirty side. The second side 30 is also called the clean side. In the filter element 1, the first side 29 of the filter insert 3 (inner package) is the radial inner side. In the filter element 1, the first side 29 of the filter element 2 (outer package) is the radial outer side. The beads 28 may be on the first side 29 and / or the second side 30 of the filter element 2 and / or the filter insert 3. Preferably, the beads 28 are arranged on the first side 29 of the filter insert 3 and on the first side 29 and the second side 30 of the filter element 2. The beads 28 may be arranged only on the side wall 26, i.e. the pleats 27 are not covered by the beads, (see Fig.15a ), it can also extend to the pleat 27, that is, the pleat 27 is covered by the beads 28 (see Fig.15b). When in use, the side walls 26 are substantially parallel to each other, so that the depth 31 of the pleats 25 is substantially the same as the width of the side walls 26. The depth filled by the beads 28 is less than the depth 31 of the pleats 25. The extension 32 of the beads is the extension of the area filled by the beads 28 in the width direction of the side walls 26. The extension 33 of the space without beads is the extension of the area not filled by the beads 28 in the width direction of the side walls 26. Preferably, the depth filled by the beads 28 is less than 80% of the depth of the pleats 25. Preferably, the depth of the pleats 25 is between 1.2 and 1.7 inches (1 inch = 25.4 mm).

[0144] Fig.16 The filter insert 3 is shown from the radial inside. The filter material is fixed by a ring 34 glued to the filter material. The beads 28 separate the pleats 25 from each other. The beads 28 are spaced apart from each other in the axial direction by a predetermined distance. The distance between the beads 28 is greater than the depth 31 of the pleats 25. Preferably, the ratio between the depth and the distance is between 0.5 and 1. More preferably, the distance is between 1.8 and 2.2 inches. More preferably, the distance varies from the top to the bottom of the filter element, i.e. in the axial direction, for example between 1 and 3 inches. Fig.17 The filter insert 3 is shown from the radial outside. The filter material is fixed by a ring 35 glued to the filter material. The beads 28 separate the pleats 25 from each other. The beads 28 fill to a depth that is less than the depth 31 of the pleats 25.

[0145] Fig.18 A filter element 1 is shown. The filter element comprises a filter element 2 made of a pleated filter material. The filter element comprises a filter insert 3 made of a pleated filter material. The filter insert 3 is inserted into the filter element 2. An inner space 4 is formed between the filter element 2 and the filter insert 3. In the inner space 4 is clean gas, because the dirty gas flow flows through the filter material of the filter insert 3 from the radial inside and flows through the filter material of the filter element 2 from the radial other side into the inner space 4. The filter element 1 comprises a base 17, which is part of the flow guide device 5. The base 17 is arranged on the top of the filter insert 3. The filter element 1 comprises a frame 36 on the top of the filter element 2. The frame 36 forms the axial end face of the filter element 1. The axial end face of the base 17 is located in a horizontal plane, and the frame 36 is located in this horizontal plane. The filter element 1 comprises a filter bottom part 7 located at the bottom of the filter element 1. The filter element 2 and the filter insert 3 are arranged on the filter bottom part 7.

[0146] Fig.19 and 20A centering device 37 is shown for centering the filter element 2 and the filter insert 3 with each other and with an end piece 16 that can be fixed on the centering device 37. The centering device 37 has the form of a cross. The centering device 37 is fixed to a housing 38. The housing 38 includes an opening 39 corresponding to the inner diameter of the filter element 2. The centering device 37 is arranged coaxially with the opening 39. The centering device 37 is located at the top of the opening 39. The centering device 37 includes an arm 40 protruding in the radial direction. The arm 40 includes a first centering portion 41 for bringing the filter element on the axial side of the arm 40 closer to the filter element 1. The first centering portion 41 protrudes in the first axial direction. The first centering portion 41 corresponds to the form of a ramp. The first centering portion 41 includes a tapered radial outer peripheral surface. The first centering portion 41 gradually changes radially inward in the first axial direction. The first centering portion 41 connects a radial outer peripheral portion 42 with a radial inner peripheral portion 43 of the arm 40. When the filter element 1 is pressed onto the centering device 37, an inner peripheral surface 44 of the filter element 2 (or the frame 36) is guided by the first centering portion 41 to a position centered on the centering device 37. The centering device 37 includes a center portion 45. The center portion 45 includes a second centering portion 46 for aligning the filter plug 3. The second centering portion 46 is closer to the filter element 1 on the axial side of the center portion 45. The second centering portion 46 protrudes in the first axial direction. The second centering portion 46 corresponds to the form of a ramp. The second centering portion 46 includes a tapered radial outer peripheral surface. The second centering portion 46 gradually changes radially inward in the first axial direction. When the filter element 1 is pressed onto the centering device 37, an inner peripheral surface of a groove formed in the filter plug 3 is guided by the second centering portion 46 to a position centered on the centering device 37. Therefore, the filter element 2 and the filter plug 3 are centered with each other and with the opening 39. Fig. 20 In the embodiment, there is a sealing member 47 at the top of the base 17, which seals the base 17 and the end member 16.

[0147] Figures 21 to 24 The installation process of the filter element 1 is shown. Fig.21 In the embodiment, the substrate 17 is placed on a plate 48. The plate 48 includes a fixing portion 49. Fig. 22 In the embodiment shown in FIG. 4 , the frame 36 is placed on the plate 48 in the axial direction, as indicated by the arrow. The frame 36 includes an opening 50 corresponding to the opening 39 and the inner peripheral surface 44, and also includes a slit 51 and an arc-shaped groove 52 for the filter element 2. Fig.23 The frame 36 is shown placed on a plate 48 . Fig.24 The filter element 2 is shown placed in a groove 52 .

Claims

1. A filter element comprising: a filter material arranged in a generally cylindrical or conical shape and having a first side and a second side, the filter material having longitudinally extending pleats formed therein, the pleats defining pleats; as well as a plurality of radially extending beads of adhesive formed on the pleats, wherein a first set of beads of adhesive are formed on a first side of the filter element and a second set of beads of adhesive are formed on a second side of the filter element, such that the first set of beads of adhesive and the second set of beads of adhesive are located on opposite sides of the filter material, wherein the beads of adhesive are used to maintain spacing between the pleats, and wherein the glue bead does not extend above the radially inner pleat, nor does it extend below the radially inner pleat; and The glue beads formed on the radially outer side of the filter material extend over the corresponding outer pleats, or do not extend over the corresponding outer pleats.

2. The filter element of claim 1, wherein the radial extent of the glue bead is less than 80% of the pleat depth.

3. The filter element according to claim 1, wherein The adhesive beads are formed into axially spaced apart rows of beads, and a ratio between the pleat depth and the axial spacing of the rows of beads is in the range of 0.5 to 1.

4. The filter element according to claim 1, wherein The adhesive beads are formed into axially spaced apart rows of beads that are axially spaced apart from each other by a predetermined distance, wherein the predetermined distance is greater than the depth of the pleats.

5. The filter element of claim 4, wherein the pleats have a depth in the range of 1.2 to 1.7 inches.

6. The filter element of claim 1, wherein: The adhesive beads are formed into axially spaced apart rows of beads, and the rows of beads are axially spaced apart by a distance in the range of 1.8 to 2.2 inches.

7. A filter cartridge for removing impurities from a turbid gas stream to be filtered, the filter cartridge comprising first and second filter elements, each filter element being a filter element according to claim 1, wherein: The first filter element is generally cylindrical; The second filter element is a filter insert that is inserted into the first filter element; An interior space is formed between the first filter element and the filter insert.

8. The filter element according to claim 7, wherein: The second filter element has a generally conical shape.

9. The filter element according to claim 8, wherein: The generally conical shape of the second filter element is a frustoconical shape.

10. The filter cartridge of claim 7 wherein the second filter element has a substantially cylindrical shape.

11. A filter element comprising: a filter material arranged in a generally cylindrical or conical shape and having a first side and a second side, the filter material having longitudinally extending pleats formed therein, the pleats defining pleats; as well as A plurality of radially extending beads of glue are formed on the pleats, wherein the beads of glue are used to help maintain spacing between the pleats and do not extend over or under the pleat knuckles of the pleats.

12. The filter element of claim 11, wherein a first set of beads are formed on a first side of the filter element and a second set of beads are formed on a second side of the filter element such that the first set of beads and the second set of beads are located on opposite sides of the filter material.

13. The filter element of claim 11, wherein the radial extent of the bead is less than 80% of the pleat depth.

14. The filter element of claim 11, wherein the pleats have a depth in the range of 1.2 to 1.7 inches.

15. The filter element of claim 11, wherein: The adhesive beads are formed into axially spaced apart rows of beads, and the rows of beads are axially spaced apart by distances in the range of 1.8 to 2.2 inches.

16. The filter element of claim 11, wherein: The adhesive beads are formed into axially spaced apart rows of beads, and a ratio between the pleat depth and the axial spacing of the rows of beads is in the range of 0.5 to 1.

17. The filter element of claim 11, wherein the glue beads are formed into axially spaced rows of beads that are axially spaced a predetermined distance from one another, wherein the predetermined distance is greater than a depth of the pleats.

18. A filter cartridge for removing impurities from a filthy gas stream to be filtered, the filter cartridge comprising first and second filter elements, each filter element being a filter element according to claim 11, wherein: The first filter element is generally cylindrical; The second filter element is a filter insert that is inserted into the first filter element; An interior space is formed between the first filter element and the filter insert.

19. The filter cartridge of claim 18, wherein the second filter element has a generally conical shape.

20. The filter element of claim 19, wherein: The generally conical shape of the second filter element is a frustoconical shape.

21. The filter element of claim 18, wherein: The second filter element has a substantially cylindrical shape.

Images