Filter system with cleaning air guide for horizontal filter cartridges

Abstract

Filter system (1) for cleaning an aerosol-like raw gas to a clean gas, with at least two horizontally arranged filter elements (2) and a cleaning gas line (3) designed to supply the filter elements (2) with compressed air for cleaning, characterized in that a compressed air supply is provided by structural and control measures such that components of the compressed air flow (8) that is used for cleaning through and passes through the filter material (7) of the two filter elements (2) are forced into a common direction, which runs in the horizontal direction, wherein the structural measures include a flow guidance device (10) that deflects the gas and particle flow (6) exiting one filter element (2) in the case of cleaning in the same direction as the gas and particle flow (6) exiting the other filter element (2) during cleaning.

Description

[0001] The invention relates to a filter system for purifying an aerosol-like raw gas containing (single or combined) impurities / pollutants / odors / dust / fines / coarse material into a clean gas, comprising at least two horizontally arranged filter elements that preferably overlap each other at least partially in the direction of gravity, for example, in the form of hollow cylindrical filter cartridges. The filter system also includes a cleaning gas line designed to supply the filter elements with compressed air for cleaning.

[0002] To achieve optimal use of the required footprint while maintaining a low overall height, filter cartridges are often housed horizontally within a raw gas housing rather than vertically suspended. This horizontal arrangement allows the filter cartridges to be stacked on top of each other. The horizontal design inevitably results in a compressed air blast during cartridge cleaning, which, against the airflow direction, forces the cleaned dust onto the cartridge below. Furthermore, the radially ejected dust is moved against gravity on the cartridge's surface and partially settles back onto the same surface during the return journey. This dust is a contaminant containing particles that must be removed during cleaning. These particles can be either fine or coarse.

[0003] The prior art includes, for example, AT 405 615 B. This document discloses a method for cleaning a dust separator that has a raw gas shaft through which the gas flows from top to bottom and filter elements projecting into the raw gas shaft transversely to the raw gas flow. The raw gas is then discharged into a clean gas shaft through these filter elements, with appropriate dust separation. The filter elements are successively and briefly pressurized with compressed air to blow off the dust particles deposited on them into the raw gas shaft. During the compressed air treatment, the flow connection between the filter elements and the clean gas shaft is interrupted. The document further discloses a device for carrying out the method.

[0004] Prior art documents DE 31 11 502 A1 and DE 20 09 815 A disclose filter systems for cleaning with horizontally arranged filter elements, in which the filter elements are simultaneously supplied with a compressed air stream.

[0005] German patent application DE 10 2014 006 473 A1 is known from the prior art. It discloses a filter device with at least one filter element having an interior space surrounded by filter material, through which a raw gas flows from the outside to the inside. A cleaning device removes adhering contaminants from the filter material. Compressed air is directed onto the filter material by the cleaning device. The interior space of the filter element is divided into at least two separate interior spaces. Each interior space is associated with a compressed air line, in which a valve is located. Each interior space is cleaned independently by supplying compressed air via the compressed air line and the open valve. This compressed air is used to blow off the contaminants adhering to the outside of the filter material from the inside of the interior space.During the cleaning process, the filter material from the other interior area is available for filtering the raw gas. However, in the aforementioned publication, the filter elements are arranged vertically.

[0006] Another vertical arrangement of filter elements, also designed in a cartridge-like form, is also known from EP 2 799 123 A1. There, a pleated air filter with reverse pulse airflow cleaning is disclosed.

[0007] In contrast, DE 196 18 198 C1 discloses the use of several horizontally oriented filter elements in a product separator. It is disclosed therein that a product separator is used for separating solid particles from a gas stream, comprising a housing and at least one substantially cylindrical filter cartridge arranged in the housing, through which the gas stream flows from the outside to the inside. At least a portion of the gas stream is guided downwards past the filter cartridge inside the housing before passing through it, and the filter cartridge can be supplied with compressed air from the inside for cleaning. To improve the cleaning effect of the compressed air, that earlier patent specification proposes supplying the compressed air only to a portion of the circumference of the filter cartridge at any one time, with the gas stream directed obliquely downwards at an acute angle.Simultaneously, the filter cartridge can be rotated around a largely horizontal axis, allowing its entire circumference to be cleaned step by step. However, this solution is relatively complex, as it requires a drive unit to rotate the filter cartridge, in addition to other disadvantages. This solution is therefore very expensive, even though it is relatively space-efficient.

[0008] The solution presented in DE 197 53 070 A1 is similarly complex and, moreover, space-inefficient, since the filter cartridges are again arranged vertically. That patent application discloses a product separator for separating solid particles from a gas stream, comprising a housing, at least one substantially cylindrical filter cartridge arranged in the housing with a filter material through which the gas stream flows, and a cleaning device for cleaning the filter material on a portion of the circumference of the filter cartridge with countercurrent purge air. The cleaning device includes at least one purge device for supplying the portion of the circumference to be cleaned with purge air and at least one collection device for collecting the cleaned solid particles, each of which has at least one outlet opening for the purge air.The opening serves as an inlet for the purge air, which in turn carries away the cleaned solid particles. These openings are located on opposite sides of the filter material along the circumference of the filter cartridge to be cleaned. To avoid a rotatable mounting of the filter cartridge, which would necessitate the installation of a large-diameter rotary seal between the filter cartridge and the housing, the purge device and the collection device are rotatable synchronously about a vertical longitudinal axis of the filter cartridge, which is fixedly mounted in the housing, in accordance with the concept of that patent application.

[0009] The solution described in EP 1 092 463 A1, concerning a filter device and a device for holding filter cartridges, is also not yet sufficiently efficient, cost-effective, or durable. Furthermore, the disadvantage described at the beginning occurs precisely with this filter device, in particular that dust blown off an upper cartridge settles on a lower cartridge, or that dust dislodged from the two cartridges and carried upwards by gravity settles back onto the respective cartridge.

[0010] The object of the present invention is therefore to eliminate the disadvantages of the prior art and to provide a solution that is as simple in design as possible and can be operated with uncomplicated and cost-effective means. In particular, it is intended to prevent uneven and / or inadequate cleaning of the filter elements across their circumference.

[0011] This problem is solved in a filter system of the generic type according to the invention by means of a compressed air supply that is designed with structural and control measures such that components of the compressed air streams used for cleaning in and passing through the filter material of the two filter elements are forced in a common direction, which runs in the horizontal direction. The structural measures include a flow guidance device that deflects the gas and particle stream exiting one filter element during cleaning in the same direction as the gas and particle stream exiting the other filter element during cleaning. Thus, the compressed air stream / rinsing stream / cleaning air stream used for cleaning in and passing through the filter material of the two filter elements is forced in a common direction.Flow components of the contaminated compressed air stream / rinsing stream / cleaning air stream exiting one filter element combine with flow components of the contaminated compressed air stream / rinsing stream / cleaning air stream exiting the other filter element to form a common gas and particle stream and are forced in a common direction.

[0012] A horizontal flow is preferably created between the filter elements, i.e., ultimately the filter cartridges / chains. This transports the released dust particles from the space between the upper and lower cartridges / filter elements / chains, preventing them from settling onto the lower cartridge / filter element / chain. The following measures are useful for establishing this cross-flow: The upper and lower cartridges should be cleaned approximately simultaneously. The air volume used for cleaning then flows at high velocity into the space between the upper and lower cartridges. The airflows from the upper and lower cartridges meet head-on, resulting in a horizontal displacement flow. This flow carries the dust particles out of the space. A sufficient volume of compressed air should be provided in a compressed air tank to operate two valves simultaneously. Using separate compressed air tanks may be preferable. It may also be advantageous to divide the cartridges into two chambers, e.g., a right / left division, each with its own cleaning valve, to reduce the amount of compressed air used. This is particularly important with smaller cartridge filters containing fewer than six cartridges, as it prevents backflow into the extraction system.One preferred application is in a deflection between the cartridges to promote a horizontal flow pattern.

[0013] Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0014] It is therefore advantageous if the structural and control engineering measures force a common gas and particle flow exiting both filter elements. The dust that accumulates on the filter cartridges during operation is thus carried away by the cleaning compressed air flow, and the resulting gas and particle flow exiting one filter cartridge, or a component thereof, and the resulting gas and particle flow exiting the other filter cartridge, or a component thereof, form a synchronized, common gas and particle flow. The geometric design and, for example, the hydraulic, electrical, or pneumatically actuated / controlled components then enable efficient cleaning.The purge flow / compressed air flow / cleaning air flow / cleaning gas flow, loaded with dust / fines / dirt / particles, of one filter cartridge-like filter element and the other filter cartridge-like filter element, then takes the same direction, namely approximately perpendicular to an imaginary line connecting the two centers of the filter elements.

[0015] It can be advantageous if the common direction of the combined gas and particle flow is essentially or exactly horizontal, particularly perpendicular to the longitudinal direction of one or both filter elements. The particle-contaminated gas flow can then be quickly removed from the surface of the two filter elements, resulting in rapid cleaning.

[0016] In a particular embodiment, the effective rinsing effect is achieved when the structural and control measures are such that both filter elements are supplied with cleaning compressed air at essentially the same time.

[0017] The structural measures include the flow guidance device, which deflects the gas and particle flow exiting one filter element in the same direction as the gas and particle flow exiting the other filter element during cleaning, thus achieving a particularly efficient rerouting of the contaminated compressed air flows.

[0018] It is advantageous if the flow guide device comprises an elongated component, such as a rod or a threshold, since, particularly in the case that this elongated component is designed to be unperforated / continuous / integral and / or one-piece and / or made of a single material, there are no areas where a misdirection of the gas and particle flow can occur.

[0019] It is advantageous if the flow guide has an angular, e.g., square, outer contour, similar to a prism or rectangle. Manufacturing such flow guides is cost-effective using particularly suitable materials. Plastics or metal alloys are suitable options.

[0020] If two main edges of the flow guide device lie in a first plane in which both central axes of the two filter elements are located, a particularly good flow modulation is achieved.

[0021] To ensure good separation of the flow from the flow guidance device, it is advantageous if two further secondary edges of the flow guidance device lie in a second plane perpendicular / orthogonal to the first plane.

[0022] It has also proven effective for the surface between a main edge and a secondary edge to be planar, flat, curved, concave, or convex. These geometric designs can also be combined. They can be combined, in particular, for the surface between a main edge and a secondary edge, as well as across the entire circumference of the flow guide device.

[0023] However, it is advantageous if all surfaces on the outside of the flow guide device are designed in the same way.

[0024] An advantageous embodiment is further characterized by the fact that the structural and control measures are designed to ensure an equally long and / or equally intensive supply of compressed air for cleaning both filter elements. This prevents asymmetry in the gas and particle flow, resulting in an equally effective cleaning sequence for both filter elements.

[0025] If the control engineering measures are designed / constituted solely as control engineering measures, then these measures can be implemented more cost-effectively. Therefore, these (simplified) control engineering measures should also be subsumed under the category of control engineering measures.

[0026] It is advantageous if the two filter elements are arranged parallel and / or equidistant from each other. Of course, more than two filter elements can also be used, in which case the explanations regarding two filter elements should apply to more than two filter elements.

[0027] An advantageous embodiment is also characterized in that the flow guidance device is arranged centrally between the two filter elements.

[0028] It is advantageous if the flow guide device is aligned parallel to one or both filter elements.

[0029] If the compressed air flow for each filter element is drawn from a common reservoir or from two separate reservoirs, costs can be reduced and a more efficient pressure supply ensured. In particular, it is advantageous to use two 12-liter pressure tanks at 5 bar. In the depressurized state, a total of 60 liters is then available. However, it should be noted that not only these 60 liters can be used for cleaning, but also the intake of additional air, resulting in an induced supply air flow, which, assuming a ratio of 1:10, amounts to 600 liters. An efficiency of 0.75% is generally assumed. The effective displacement volume used for cleaning is typically between 300 and 600 liters, preferably 450 liters.The space between the two filter elements has a volume of approximately 300 liters. The proportion of effective cleaning air for the critical area is typically 90 liters. Deviations of + / - 15% can be acceptable here. In any case, an increase in pressure is desired in the critical area. The aforementioned 600 liters are blown into both the upper and lower cartridges simultaneously.

[0030] It should be mentioned that the storage container can be designed as, for example, an incompressible compressed air tank.

[0031] It is also advantageous if a (single) valve is installed between the compressed air tank(s) and the filter element(s) for compressed air metering (each).

[0032] It is advantageous to have a valve in a cleaning line connecting each compressed air tank and each filter element.

[0033] Efficient cleaning is possible if the combined gas and particle flow during the cleaning process is designed as a crossflow and / or horizontal displacement flow.

[0034] It is further recommended that a filter element, in the form of a filter cartridge, be divided into two or more chambers by an internal partition that is present / inserted within it.

[0035] If each chamber has its own cleaning valve, the supply of compressed air to each chamber can be accomplished efficiently.

[0036] It has proven effective if the flow guide device, designed to force the deflection of the gas and particle flow entering the space between the two filter elements, creates a horizontal flow. Naturally, a targeted selection of materials is also advisable.

[0037] Another embodiment is also characterized in that the filter element, configured as a filter cartridge, is designed to be permeated by the aerosol-like raw gas stream from the outside to the inside, and has a cleaning device including the compressed air supply, which is prepared to clean the filter cartridge by applying a compressed air stream against the flow direction of the raw gas stream, wherein the cleaning device is preferably designed such that it directs the compressed air stream horizontally away from the filter cartridge.

[0038] It is advantageous if the flow guide device, designed as a deflecting element, is arranged vertically below and / or above the filter cartridge and is designed to deflect the compressed air flow in a horizontal direction.

[0039] If the deflecting element has a diamond-shaped cross-section, a particularly efficient cleaning flow is achieved.

[0040] It is advantageous if the deflection element is the same length as, or longer than, the filter cartridge in the axial direction. This prevents unwanted flow.

[0041] If the interior of the filter cartridge is divided into at least two separate interior areas, each with a cleaning valve, the control can be achieved with particularly simple means, as already indicated.

[0042] It is also advantageous if the cleaning device has at least one pressure tank that is dimensioned so that the vertically stacked filter cartridges can be pressurized simultaneously.

[0043] It is advantageous if the filter cartridge is arranged in a first horizontal plane.

[0044] It is also advantageous to have another filter cartridge in a second horizontal plane that is vertically offset from the first horizontal plane.

[0045] The invention is explained in more detail below with the aid of a drawing. The drawing shows: Fig. 1 a side view of a filter system according to the invention, Fig. 2 a perspective view of the filter system made of Fig. 1 without in Fig. 1 illustrated storage containers of the type of compressed air tanks, Fig. 3. A view of the filter elements from Fig. 1 and Fig. 2 on their end faces, with a flow guide device arranged between them, which acts as a deflecting element, in symbolic visualization of the flow vectors of the cleaning gas / compressed air flow penetrating the filter material of the filter cartridges, and Fig. 4 one to Fig. 3. Comparable representation of a section of a filter system according to the invention.

[0046] The figures are purely schematic and serve only to illustrate the invention. The same elements are identified by the same reference symbols.

[0047] In the Fig. Figure 1 shows a section of a filter system 1 according to the invention. The filter system 1 is used to clean aerosol-like raw gas in order to obtain clean gas. It comprises at least two horizontally arranged filter elements 2, offset from each other vertically. Each filter element 2 is associated with a cleaning gas line 3. Compressed air 4 can be passed through the cleaning gas line and then enters the interior of the filter element 2.

[0048] During this cleaning process, a gas and particle stream 6, containing dust / fine particles / coarse particles, emerges from a surface 5 of the respective filter element 2. This gas and particle stream is thus the compressed air stream 8 exiting through the filter material 7 of the respective filter element 2. Structural and control measures are in place to ensure a common direction for the compressed air stream exiting the filter elements 2. This is particularly evident in the Fig. 3 and Fig. 4. There, the common gas and particle flow or the common escaped compressed air flow / compressed air flow section is visualized with reference numeral 9.

[0049] Returning to Fig. 1. The presence of a flow guide device 10 was noted. The flow guide device 10 acts as a deflecting element 11.

[0050] As can be clearly seen, the deflecting element 11 is exactly as long as each of the two filter elements 2. The deflecting element 11 is arranged vertically exactly above the lower filter element 2, with the upper filter element 2 being arranged exactly vertically above the deflecting element 11.

[0051] As in the Fig. 2 and Fig. As can be clearly seen in Figure 3, the filter element 2 is designed in the form of a hollow cylindrical filter cartridge 12 with, for example, a fan-like structure. A partition 13 is arranged inside each of the two filter cartridges. The outer diameter of each filter cartridge 12 can be approximately 408 mm + / - 10%.

[0052] The flow guide device 10, of the type of deflecting element 11, has two main edges 14 and two secondary edges 15. See in particular the following. Fig. 3. The distance between a main edge 14 and a secondary edge 15 should be at least approximately 100 mm + / - 10%. The corresponding surface between the respective main edge 14 and the respective secondary edge 15 is preferably planar, but can also be curved, in particular convex or concave. The respective surface is referenced by the reference numeral 16.

[0053] Returning to Fig. It should also be explained that a storage container 17, similar to a compressed air tank 18, is connected to the cleaning gas line 3. A valve / shut-off valve / two-way valve 19 is installed between the respective compressed air tank 18 and the filter element 2.

[0054] The displacement volume is visualized with the reference number 20. Reference symbol list 1 filter system 2 filter elements 3 Cleaning gas line 4 Compressed air 5 Surface area of ​​the filter element 6 Gas and particle flow 7 Filter material 8 Compressed air flow 9. Common gas and particle flow / common escaped compressed air flow 10 Flow guide device 11 Deflection element 12 filter cartridges 13 Partition wall 14 Main edge 15 Secondary edge 16 area 17 storage containers 18 compressed air tank 19 valve 20 Displacement volume

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