Filter cartridge for hot gas filtration, as well as the use of such a filter cartridge and filter apparatus with such filter cartridges

Abstract

Filter candle for hot gas filtration, particularly for industrial applications, comprising a support basket (9) with a longitudinal extent corresponding to a multiple of its diameter, with several support basket struts (11) arranged circumferentially at intervals from one another following its longitudinal extent, and with support basket rings (12, 12.1) holding the support basket struts (11) in position, further comprising an annular filter body (10) circumferentially enclosing the support basket (9), which is deformable in the radial direction and on which the fluid to be filtered flows from the outside, and comprising means for holding the filter candle (8, 8.1) for example on a filter base (5), wherein the filter body (10) is made up of a support substrate (14) having openings (15) extending over the planar extent of the filter body (10) and porous sintered metal filling the openings (15) of the support substrate (14), and the inner circumference of the filter body (10) pointing towards the support basket (9) is larger than the circumference of a virtual surface enclosing the support basket struts (11).

Description

[0001] The invention relates to a filter cartridge for hot gas filtration, especially as used in industrial applications. The invention further relates to the use of such a filter cartridge and a filter apparatus with several such filter cartridges.

[0002] There are numerous sources of dust, especially in industrial processes where the dust should not be released into the environment. Filter units are used to remove dust from rooms and process gases. These filter units consist of many individual filter cartridges, which in many cases are suspended within a filter tray. The filter tray itself separates the raw fluid side from the clean fluid side within a filter housing. The filter cartridges suspended in the filter tray extend their filter bodies into the raw fluid side. Filter units with such filter cartridges also clean hot gases of entrained solid particles, such as those produced during cement or clinker manufacturing. To withstand the temperatures encountered, these filter cartridges are made of either ceramic or sintered metal.The filter bodies of these filter cartridges are annular and closed at the end facing the raw fluid, either by a seal or, in the case of ceramic filter cartridges, by filter material. To ensure sufficient dimensional stability and effective filtration—that is, the removal of solid particles entrained in the raw gas—sintered metal filter cartridges typically have wall thicknesses of 3 mm to 5 mm, while ceramic filter cartridges have wall thicknesses of at least 1 cm. For ceramic filter cartridges, the required wall thickness also depends on the length of the cartridge, which can be several meters long. Longer ceramic filter cartridges therefore require a greater wall thickness than shorter ones. The wall thicknesses of ceramic filter cartridges are approximately two to three times greater than those of sintered metal filter cartridges. Due to the nature of the material, ceramic filter cartridges are brittle.To secure the filter cartridges in a filter base, special measures must be taken to prevent damage to the filter cartridge suspension from vibrations. Increased care is also required when handling larger ceramic filter cartridges, particularly during transport, when inserting them into a filter base, and when removing them.

[0003] The filter cartridges become clogged with increasing filter operation, which reduces the filter apparatus's efficiency in terms of raw fluid throughput and also increases the back pressure in the fluid flow, which is undesirable. For this reason, the filter cartridges must be cleaned periodically. In the hot gas filter systems described above, this is done by backflushing against the filter flow direction. During such a cleaning process, not only the filtrate adhering to the outside of the filter cartridge as a filter cake should be removed, but also, as far as possible, the solid particles trapped in the pores of the filter body. To achieve sufficient cleaning, it is necessary to carry out the backflushing process continuously over an extended period.The purge gas, flowing in the opposite direction to the filter flow direction and thus from the inside out, is passed through the filter cartridges at a relatively low velocity for the duration of the purge process. This is necessary to wash out the particles deposited in the walls of the filter cartridges.

[0004] The above applies equally to filter apparatus for removing dusts and thus to gas filtration as well as to filter apparatus intended to remove solid particles carried along with a liquid.

[0005] Even though such filter cartridges and the filter apparatus equipped with them are suitable and have proven effective not only for hot gas filtration but also for other filtration processes, it would be desirable if the backflushing process for cleaning filter cartridges suitable for hot gas filtration could be carried out less time-consuming and therefore more energy-efficiently. After all, the filter cartridges involved in a backflushing process cannot be used for their intended task—filtering raw gas—for the duration of the rinsing procedure.

[0006] If a filtration process is to be continuous and not discontinuous, interrupted by the longer but necessary backwashing processes, the filter apparatus must be equipped with a correspondingly larger number of filter cartridges, or several filter apparatuses must be operated, of which only a subset is involved in the active filtration process, while others are backwashed for cleaning.

[0007] The object of the invention is therefore to propose a filter candle, a use thereof and a filter apparatus equipped with such filter candles, which components are not only suitable for hot gas filtration, but above all can also be cleaned in a significantly shorter time by backflushing.

[0008] According to the invention, this problem is solved, firstly, by a filter candle for hot gas filtration, particularly for industrial applications, comprising a support basket with a longitudinal extent corresponding to a multiple of its diameter, with several support basket struts arranged circumferentially at a distance from one another following its longitudinal extent, and with support basket rings holding the support basket struts in position, further comprising an annular filter body circumferentially enclosing the support basket, deformable in the radial direction, and with the fluid to be filtered flowing on its outer surface, and comprising means for holding the filter candle approximately on a filter base, wherein the filter body is composed of a carrier substrate having openings and extending over the planar extent of the filter body, and porous sintered metal filling the openings of the carrier substrate.and the inner circumference of the filter body facing the support basket is larger than the circumference of a virtual surface enclosing the support basket struts.

[0009] According to the invention, this problem is further solved by using such a filter candle in a filter apparatus which has a pulse backwashing device for cleaning its filter candles.

[0010] Furthermore, the problem is solved by a filter apparatus having the features of claim 13.

[0011] Due to the design of its filter body, the filter cartridge according to the invention is suitable, alone or together with a plurality of similar filter cartridges, for use in a filter apparatus for industrial applications where conventionally only thick-walled ceramic or sintered metal filters have been used. Compared to conventional ceramic filter cartridges, this filter cartridge is characterized by its insensitivity to vibrations, for example, in a vibrating environment or during earthquakes. A particular advantage of the filter body of the filter cartridge according to the invention is that the filter body has a support substrate with openings, so that the mechanical stability of the filter body is primarily derived from the support substrate and, unlike sintered metal thick-walled filters, not from the porous material from which the filter body is manufactured.A suitable support substrate can be, for example, a wire mesh or, as in a preferred embodiment, an expanded metal strip. Such a support substrate offers numerous possibilities for adapting it to the desired application. This includes, for example, the stretch ratio, the width of the webs connecting the nodes (which also determines the thickness of the filter body), and the like. Since the filter material filling the openings—sintered metal—in this filter body ultimately only serves to fill the openings, the porous sintered metal filling the openings can also be made from relatively small metal grains to achieve relatively high porosity with a small pore size.Crucially, the inclusion of a support substrate within the filter body allows for a significantly thinner wall thickness compared to conventional sintered metal thick-walled filters. The wall thickness of such a filter body is typically only a few tenths of a millimeter, for example, 0.4 mm to 0.6 mm. The wall thickness of the filter body is typically between 0.25 mm and 0.8–1.0 mm. Depending on the size and the grain sizes used in the production of the sintered metal, the wall thickness can also be greater.

[0012] The design of this filter cartridge's filter body, with its support substrate and the porous sintered metal filling the openings, not only offers a significant weight reduction but also allows it to function primarily as a surface filter due to its thin walls. Therefore, such a filter cartridge does not require energy- and time-consuming backwashing for cleaning. Instead, this filter body design allows for cleaning via a pulsed backwash process, in which one or more backwash fluid pulses are applied against the filter flow direction through the filter body.

[0013] The cleaning process is supported by the material selection and thin walls of the filter body, as well as by the inclusion of a support basket within the filter element. The filter body is dimensioned to allow its inherent deformability, resulting from the material choice, to be effectively utilized during the backwashing process. This is achieved by making the inner diameter of the filter body slightly larger than the virtual surface area encompassing the support basket struts. This allows the filter body to expand radially, and during active filtration, the filter flow direction causes the filter body to deform radially inwards, towards the support basket struts. The support basket ensures that the filter body does not deform excessively, thus maintaining an open filter channel.This also ensures filter operation at high flow rates. However, during the intended pulse backwash for cleaning the filter cartridge, the filter body is moved radially outwards, away from the support basket struts. This promotes the flaking off of filtrate on the surface of the filter body and the expulsion of filtrate particles located within the wall. During these movements of the filter body, it is deformed similarly to kneading, but not stretched due to the material used. Such radial deformation of the filter body does not need to be particularly large. A few tenths of a millimeter of radial deformation is sufficient.Typically, filter cartridges with a larger diameter filter body will have greater radial deformability than filter bodies with a smaller diameter. The support basket struts and rings can be provided, for example, by strips of sheet metal or pieces of wire, with the rings and struts typically being welded together.

[0014] The filter element design described above allows for a particularly effective adaptation to the specific operating conditions of the filtration process, whether regarding porosity or to counteract the potential aggressiveness of the fluid being filtered. Therefore, the metal or metal mixture used to produce the porous sintered metal can be selected to best suit the fluid being filtered. It is also possible, for example, to incorporate non-sintered material particles, such as ceramic particles, into the material to support the sintered metal particles during the sintering process.

[0015] Another advantage of this type of filter cartridge compared to ceramic filter cartridges is that the filter body is weldable and can therefore be connected to other components required to complete the filter cartridge, such as a mounting flange, an end closure or an end coupling piece or the like, by means of a fusion joint.

[0016] A further advantage of this filter cartridge, or rather its filter body, is that the wall thickness of the filter body can be determined by the thickness of the support substrate. The sintered metal particles are incorporated into the openings of the support substrate. The edges of the opposing sides of the support substrate can act as scrapers for the material being incorporated into its openings. To reduce the filter back pressure, a preferred embodiment provides for the wall thickness of the sintered metal to be slightly greater than the thickness of the support substrate, at least on its outer surface exposed to the fluid being filtered. This ensures that the support substrate is covered with a certain thickness of sintered metal on at least one of its two flat sides. The protrusion of the sintered metal beyond the flat sides of the support substrate does not need to be particularly large to achieve this.A protrusion of 0.03 mm to 0.08 mm is considered sufficient for this purpose. The grain size of the particles used to build up the sintered metal layer also influences the required protrusion thickness.

[0017] A ring-shaped filter body made of this material can be assembled from one or more sintered metal strips, in the latter case being joined at their longitudinal sides by means of a welded connection to form a larger sintered metal body.

[0018] The deformability of such a filter body also allows for the production of filter bodies with different cross-sectional geometries. Typically, such a filter cartridge is designed with a rounded, especially circular, cross-sectional geometry. However, other cross-sectional geometries are also possible, for example, oval or polygonal cross-sectional geometries with rounded edges. Furthermore, if an increase in the surface area of ​​the filter body is desired, the sintered metal strip can be given a significantly larger surface area compared to the outer surface of the support cage during manufacturing, for example, by pleating. In this respect, the possibility of shaping such a sintered metal strip can also be used to create smaller structures to increase its filter surface area during the production of the filter cartridge.

[0019] A filter apparatus according to the invention comprises several, typically a large number of, such filter cartridges, which are typically held in a filter base. For this purpose, the filter cartridges preferably have a mounting flange at one end, with the side of which facing the filter body resting on the top of the filter base, preferably with a suitable seal interposed, if necessary. Retainers can be provided to seal the suspended filter cartridges against the filter base with an interposed seal. The filter base is located in a filter housing. This housing separates the raw fluid side from the clean fluid side. Such a filter apparatus also has a pulse backwash device.This unit is connected to a rinsing fluid source, such as a pressurized gas source, and features a pulse valve that is briefly opened for backflushing, allowing a cleaning fluid pulse to be introduced into the clean fluid side of the filter housing. Each filter cartridge has its own cleaning fluid outlet to deliver this fluid directly to the filter cartridges. Suitable materials for the filter body, particularly for hot gas filtration, include steel grades 1.4845, 1.4404, and 1.4539. Nickel-based alloys are also used. This material specification applies to both the substrate material and the sintered metal particles.

[0020] A filter body for hot gas filtration, as described above, has a total porosity (support substrate and sintered metal) of approximately 45%.

[0021] The invention is described below with reference to an exemplary embodiment and the accompanying figures. These show: Fig. 1: A schematic representation of a filter apparatus according to the invention with a plurality of filter candles arranged in a filter housing, Fig. 2: A perspective view of a filter candle of the filter apparatus of the Fig. 1, Fig. 2a: a cross-sectional view of the end section of the filter candle of the Fig. 2, Fig. 2b: a partial sectional view through the lower end section of the filter candle of the Fig. 2, Fig. 3: a sectional view to illustrate the structure of the filter body of the filter candle described above, Fig. 4: A cross-sectional view through the filter candle of the Fig. 2 facing towards their raw fluid-side end, Fig. 5: a partial longitudinal section view of another filter candle with impact elements suspended inside it and Fig. 6: a cross-sectional view corresponding to that of the Fig. 4 on the filter candle of the Fig. 5.

[0022] A filter apparatus 1 serves to filter a dust-laden hot gas. The filter apparatus 1 comprises a filter housing 2 with a raw gas inlet 3 and a clean gas outlet 4. Inside the filter housing 2 is a filter plate 5, which separates the raw gas side 6 from the clean gas side 7. The filter plate 5 has a multitude of filter candle openings, with a filter candle 8 suspended in each filter candle opening. Fig. Figure 1 shows four filter candles 8 arranged side by side. The filter base 5, extending to the inner wall of the filter house 2, carries a multitude of further filter candles 8 arranged in a grid pattern.

[0023] In the illustrated embodiment, all filter cartridges 8 of the filter apparatus 1 are identical. Each filter cartridge 8 has a support basket 9, which is enclosed on the outside by a filter body 10. The support basket 9 has several support basket struts 11, four in the illustrated embodiment, which are held in position by several support basket rings 12 arranged radially outside the support basket struts 11 in the illustrated embodiment. The support basket struts 11 are arranged circumferentially at equal angular intervals from each other. The length of the support basket struts 11 defines the length of the filter body 10 and thus the length of the filter cartridge 8 shown in the figures. The support basket struts 11 and the support basket rings 12 are strips of sheet steel and are welded together. The cross-sectional geometry of the support basket 9 is circular (see also Fig. 4).

[0024] The filter body 10 is a body made from several individual sintered metal strips 13. Each sintered metal strip 13 has an expanded metal strip 14 as a support substrate (see Fig. 3) The openings 15 of the respective expanded metal strip 14 are, as shown Fig. 3. Sintered metal is incorporated and solidified by a sintering process and positively connected to the expanded metal strip 14. The sintered metal is schematically represented in this figure by the grid. Fig. 3. The nodes of the expanded metal strip 14 are identified by reference numeral 16, and the connecting webs are identified by reference numeral 17. The wall thickness of the filter body 10 is also determined by the wall thickness of the expanded metal strip 14. As shown in Fig. As can be seen in Figure 3, the wall thickness of the sintered metal on the illustrated upper surface is slightly greater than the thickness of the expanded metal strip 14. The outer surface of the filter body 10 with the sintered metal protrusion represents the upstream side of the filter body 10. In the illustrated embodiment, the protrusion is 0.04 mm. Before the sintered metal powder is incorporated into the openings 15 of the expanded metal strip 14, it may have been calendered. In the illustrated embodiment, the Fig. 3. Material thickness of the sintered metal strip shown: 0.4 mm.

[0025] The filter body 10, which is cylindrical in its basic form, has an inner circumference that is larger than the virtual surface area enclosing the support basket struts 11. This virtual surface area corresponds, as shown from Fig. 4, the inner circumference of the support basket rings 12. The inner diameter of the filter body 10 can also be somewhat larger than the outer circumference of the support basket rings 12. The filter body 10 is not clamped to the support basket struts 11. Furthermore, the filter body 10 is not connected to the support basket struts 11, nor, in the illustrated embodiment, to the support basket rings 12, by a joining connection. Due to the play built in between the inside of the filter body 10 and the support basket struts 11 – the deformation play – the filter body 10 is deformable in the radial direction. During filter operation of the filter apparatus 1, the raw gas flows radially onto the filter cartridges 8. Enclosed particles to be separated are deposited on the outer surface of the filter body 10 of each filter cartridge 8.The inflow pressure acting on the filter cartridges 8, which increases with the build-up of the filter cake through the successive particle separation as filtrate on the outside of the filter body 10, leads to a radial inward deformation of the filter body 10. This causes the filter body 10 to be drawn towards the support basket struts 11 and, if necessary, further pressed in between two adjacent support basket struts. Such a deformation of the filter body 10 is in . Fig. 4 indicated by the griddled block arrows.

[0026] The filter cartridges 8, in addition to their support basket 9 and filter body 10, have a mounting flange 18 with a connecting collar 18.1, which is connected to the end of the filter body 10 facing the clean gas side 7. The opposite end of the filter body 10 is closed by a closure 19. To connect the filter body 10, including the support basket 9, to the mounting flange 18 and to close the opposite end by means of a base 20, the end support basket rings 12.1 are designed with a greater longitudinal extent than the other support basket rings 12, in order to provide an outer contact surface for the inner circumference of the edge section of the filter body 10. A clamping ring 21, 21.1 is provided concentrically to each end support basket ring 12.1 on the outside of the filter body 10.The end connection of the filter body 10 at its end supporting the mounting flange 18 and at its opposite end is shown in a sectional view in the . Fig. 2a and Fig. 2b shown. The filter body 10 is positioned with its edge section between the respective end support cage ring 12.1 and the clamping ring 21 or 21.1, which is also made from a strip of sheet steel, in a sandwich position. Each clamping ring 21, 21.1 exerts a radial surface preload on the outside of the filter body 10 and is typically slotted for this purpose. This sandwich position allows the clamping ring 21, 21.1 to be welded to the respective support cage ring 12.1 at its end face facing away from the filter body 10, as shown in the Fig. 2a and Fig. 2b is indicated by the respective weld seam 22. The end of the edge section of the filter body 10 is also integrated into the weld. Thus, both the respective end support basket ring 12.1 and the clamping ring 21 or 21.1 arranged on the outside of the filter body 10 act to dissipate heat from the filter body 10, so that there is no risk of uncontrolled burning of the filter body 10 in its end edge sections when creating the fusion joint (welding). Thus, the filter body 10 is connected to the support basket 9 only at its two end edge sections, namely the support basket rings 12.1, by means of the joint described above. As shown in Fig. As can be seen in 2a, the upper support basket ring 12.1 is placed on the connecting collar 18.1 of the mounting flange 18 and integrated into the weld 22.

[0027] The filter apparatus 1 further comprises a pulse backwash device 23. This includes a pulse valve 24, which is connected to a backwash gas source in a manner not shown in detail. The pulse valve 24 is controlled by a control unit not shown in the figures. A backwash line 25 is connected to the pulse valve 24. Backwash gas is supplied to each filter cartridge 8 via this line. Each filter cartridge 8 has a cleaning fluid outlet 26, which is in turn connected to the backwash line 25. The cleaning fluid outlet 26 is located in the outlet-side end section of the filter body 10.

[0028] To clean the filter cartridges 8 located in the filter housing 2, the raw gas supply is stopped and backwashing is initiated. For this purpose, the pulse valve 24 is briefly opened once or several times, so that a backwash gas pulse, exiting at high velocity from the respective cleaning fluid outlet 26, is introduced into each filter cartridge 8. The pulse duration can be between 50 and 200 ms. This provides a large quantity of purge gas in a short time. This ensures that not only particles located within the wall of the filter body 10, but especially particles adhering to its outer surface – the filtrate – are dislodged by the backwash gas flowing through the filter body 10 against the filter flow direction.The backwash gas pulse, introduced into the filter channel of the filter cartridges 8, also ensures that the filter body 10, in its sections previously deformed radially inwards by the filtration process, is deformed in the opposite direction, and thus radially outwards. Fig. Figure 4 indicates this re-deformation by the radially outward-pointing block arrows. The mechanical deformation movement of the filter body 10 thus sustainably supports the cleaning process, intensifying it. Due to the very short time required for the cleaning process, this procedure is energy-efficient simply because of its brief duration and, above all, only interrupts the filtration process briefly. The filtrate cleaned by the filter cartridges 8 falls to the bottom of the filter housing 2 and can be removed and discharged from the filter housing 2 via a discharge valve 27.

[0029] The filter apparatus 1 further comprises a current-generating device for heating the filter cartridges 8. For this purpose, the filter cartridges 8 are connected in an electrical circuit. The electrical resistance of the filter cartridges 8, and in particular their filter body 10, is used like a resistance heating element to produce the desired heating when the filter cartridges 8 are energized. The design of the filter bodies 10 with their expanded metal support substrate is particularly advantageous. Since this substrate extends over the entire length of the filter body 10, a defined electrical resistance is provided. The conduction of an electric current along the longitudinal extent of a filter body 10 is therefore not dependent on the irregular contact patterns of the sintered metal particles with one another. The current-generating device of the filter apparatus 1 in the illustrated embodiment operates with alternating current.The phase is provided by a contact network 28 extending over the cross-sectional area of ​​the filter housing 2. This network can, for example, be a mesh-like structure made of an electrically conductive material. The contact network 28 is insulated from the filter housing 2. The neutral conductor is connected to the filter base 5. The filter cartridges 8 make contact with the contact network 28 via their base 20.

[0030] Heating the filter cartridges 8 is useful, for example, for preheating during the filtration of warm or hot gases. This prevents the dew point of the gas being filtered from being undershot due to an insufficiently heated filter cartridge. This avoids condensation. Heating the filter cartridges is also advantageous for drying hygroscopic filtrate before purification, thereby promoting the flaking process of the filter cake.

[0031] A particular advantage is that no additional components, such as heating wires or the like, are required to heat the filter candles 8 to the desired temperature. This also keeps the manufacturing process of the filter candles 8 simple.

[0032] Fig. Figure 5 shows another filter candle 8.1, which is constructed like the filter candle 8 of the previously described figures. Therefore, the preceding statements apply equally to the filter candle 8.1. The filter candle 8.1 differs from the filter candle 8 in that several impact elements are arranged in its filter channel 29. In the illustrated embodiment, the impact elements are impact chains 30 suspended in the filter channel 29. The impact chains 30 are link chains equipped with several impact pieces 31 arranged at intervals from one another. The impact pieces 31 are impact discs that project circumferentially beyond the links of the impact chain 30. The thickness of the impact pieces 31 decreases radially towards their outer edge.Due to this longitudinal axial projection of the striking pieces 31 relative to the links of the striking chain 30, this projection forms a fluid impact surface 32 in each case. Such a fluid impact surface 32 is located on each flat side of the striking pieces 31.

[0033] The filter cartridge 8.1 is in the Fig. In the sectional view shown in Figure 6, in which the filter body 10 is shown in cross-section, the arrangement of the impact chains 30 used in this embodiment can be clearly seen. The impact chains 30 are arranged close to the inner wall of the filter body 10.

[0034] During pulse backwashing with the pulse backwash device 23, the impact chains 30 with their impact pieces 31 are moved towards the filter body 10 when a backwash pulse is introduced into the filter channel 29 of the filter candle 8.1, due to the introduced gas pulse, in the manner of a blow. This serves the purpose of causing the impact pieces 31 to strike against the inside of the filter body 10 and thereby promote the cleaning process. With each backwash pulse, the impact chains 30 or the impact pieces 31 each receive at least two movement pulses: a first movement pulse when the backwash pulse is introduced into the filter channel 29 and a second time when the introduced gas pulse is reflected off the bottom 20 of the filter candle 8.1 and travels in the opposite direction towards the filter body 10. Fig.The impact of the impact pieces 31, shown in Figure 5, occurs on the underside of the impact pieces 31. Due to the oscillating suspension of the impact chains 30, the impact pieces 31 typically strike the inner wall of the filter body 10 multiple times with each backwash gas pulse. The impact of the impact pieces 31, or even individual chain links, against the inner wall of the filter body 10 also deforms the filter body 10, thus supporting the radial outward deformation of the filter body induced by the backwash gas pulse. Furthermore, the cleaning process is also optimized by the coupling of vibrations.

[0035] The installation of such impact elements is particularly advantageous for the aforementioned filter cartridges 8.1 due to their intended deformability in the radial direction. This is not possible with ceramic filter cartridges otherwise used for hot gas filtration because of the resulting damage and destruction. Furthermore, the cleaning result for the filter cartridges 8.1 with the impact chains 30 suspended in their filter channel 29 is significantly better than with conventional methods of introducing vibrations into a filter cartridge, for example, by means of a vibrator.

[0036] The invention has been described with reference to exemplary embodiments. Without departing from the scope of protection described by the applicable claims, numerous further embodiments of the inventive concept would be apparent to a person skilled in the art, without these needing to be explained in more detail within the scope of these explanations. Reference symbol list 1 filter apparatus 2 Filter House 3 Raw gas inlet 4 Clean gas outlet 5 filter base 6 Raw gas side 7 Clean gas side 8, filter candle 8.1 9 Support basket 10 filter bodies 11 Support basket strut 12, 12.1 Support basket ring 13 sintered metal strips 14 Carrier substrate / expanded metal strips 15 Opening 16 knots 17 Bridge 18 Mounting flange 18.1 Connecting collar 19 Closure 20 floor 21, 21.1 Tension ring 22 weld seam 23 Pulse backwash device 24 pulse valve 25 Backwash line 26 Cleaning fluid outlet 27 Sampling valve 28 contact network 29 Filter channel 30 impact chain 31 striking piece 32 Fluid impact area

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