AU2003233229B2

AU2003233229B2 - Cleaning device for tubular filter elements

Info

Publication number: AU2003233229B2
Application number: AU2003233229A
Authority: AU
Inventors: Peter Hoffken; Frank Ott
Original assignee: HIMENVIRO DEUTSCHLAND GmbH
Current assignee: HIMENVIRO DEUTSCHLAND GmbH
Priority date: 2002-05-28
Filing date: 2003-05-02
Publication date: 2008-10-30
Anticipated expiration: 2023-05-02
Also published as: AU2003233229A1; EP1507579A1; ATE540743T1; EP1507579B1; NZ537227A; WO2003099419A1; DE20208300U1; DK1507579T3

Abstract

Disclosed is a device for tubular filter elements which extend from the separating floor of a dust filter into the dust-laden air chamber thereof and several of which are combined to form a group that is jointly inserted in the separating floor. A pneumatic pipe (11) is disposed above the outlet ports of the filter elements. Injectors (14) are flowably connected to said pneumatic pipe (11) so as to discharge a jet of compressed air into the outlet ports of the filter elements, which are disposed underneath. In order to create a cleaning device with a reduced loss of flow during the cleaning process, resulting in the filter elements being rinsed in a more efficient manner, an injector (14) which is directed into the outlet port (15) of the filter element (5) is positioned above each filter element (5) of the group. The injectors (14) which are assigned to the group of filter elements (5) are disposed on the floor (13) of a common distribution chamber (12) that is connected to the pneumatic pipe (11).

Description

03 028 1 INTENSIV-FILTER GmbH Co. KG VoSkuhlstraSe 63 D-42555 Velbert 04.29.2003 Cleaning device for tubular filter elements The invention relates to a cleaning device for tubular filter elements extending from the dividing plate of a dust filter into its dusty air chamber, of which in each case a plurality of filter elements are combined into a common group inserted into the dividing plate, having a compressed air line arranged above the outlet openings of the filter elements, and injectors which have a flow connection to the compressed air line for discharging a compressed air jet into the outlet openings of the filter elements, arranged at the bottom.

A device which is widespread in practice of the regeneration of a dust filter is known, for example, from DE 44 40 279 Al. The filter elements are distributed uniformly over the area of the dividing plate between the dusty air chamber and clean air chamber, and project under their own weight into the dusty air chamber located at the bottom, so that the dust-containing air flows through them from the outside to the inside. The interior of the filter elements is connected to the clean air chamber, which is arranged above the dividing plate, which is operated at a lower pressure as compared with the dusty air chamber, and from which the clean air leaves the filter. The filter elements have to be freed from the layers of dust adhering to their outer sides, and therefore regenerated, by means of periodic flushing, to such an extent that continuous operation of the filter is possible.

03 028 2 For this purpose, it is known for example to clean the filter elements by means of a compressed air pulse injector system such that the dust or product particles adhering to the outer side of the filter elements are blown off by being backwashed with compressed air.

High requirements are placed on the regeneration of the filter elements, in particular when such filters are used in production plants having frequently changing products. In the event of such a use of the filter, it is necessary to clean the entire dusty air chamber, including the tubular filter elements, such that, during a product change, product adulteration or product contamination is avoided unconditionally. Such hygienic operation is imperative, above all when processing foodstuffs, pharmaceuticals or medical products.

A further device for the regeneration of a dust filter is disclosed by EP 1 095 688 Al. In this dust filter, no separate filter elements are used; instead in each case a plurality of filter tubes are combined in groups to form a filter bundle. The distance between the individual filter elements of such a group is smaller than the distance of the groups from one another. Such a filter operates with considerably shortened lengths of the filter elements, which means that it is also possible to use as a material inherently stable filter materials, for example an inherently stable needle felt with a very smooth surface, high air permeability and a wall thickness of no more than 0.6 mm. With relatively short filter bundles, a relatively high throughput of air and therefore throughput of dusty air to be cleaned can be achieved. The filter according to EP 1 095 688 Al is also provided with a cleaning device which is arranged at the top and operates with compressed air pulses. In this case, an individual injector expels a compressed air jet simultaneously into five to six filter elements forming the group. Additionally 00

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provided is a collecting nozzle which is arranged on the dividing plate around the group of filter elements and which deflects the injector jet into the filter bundle. In this case, however, considerable inflow losses arise, which can no longer be compensated for by the intrinsically very powerful injector.

A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.

N A preferred outcome of the invention is to provide a cleaning device for dust filters having filter elements in each case combined into groups, which is distinguished by reduced flow losses during the cleaning operation and therefore by efficient flushing of the individual filter elements.

Accordingly, the invention provides a cleaning device for tubular filter elements extending from the dividing plate of a dust filter into its dusty air chamber, of which in each case a plurality of filter elements are combined into a common group inserted into the dividing plate, having a compressed air line arranged above the outlet openings of the filter elements, and injectors which have a flow connection to the compressed air line for discharging a compressed air jet into the outlet openings of the filter elements, arranged at the bottom, wherein above each filter element of the group there is located a dedicated injector aimed into the respective outlet opening of the filter element, and in that the injectors assigned to the group of filter elements are arranged at the bottom of a common round distribution chamber, which is connected to the compressed air line.

Above each filter element of the group, there may be located a dedicated injector aimed into the respective outlet opening of the filter element, and that the injectors assigned to the group of filter elements may be arranged at the bottom of a common distribution chamber, which is connected to the compressed air line. In this way, a cleaning device that regenerates the filter is V WronlDanioSpecADMC 2003 233229 15opO8 doc 00 provided for filter elements which are arranged in a group and preferably in a O- circular group. The compressed air jet discharged by the injectors reaches the respectively associated filter element on the shortest route and without

ID

deflection, for which reason the cleaning device operates with high efficiency.

a The device according to the invention is not just suitable for dust filters to be

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newly produced but in particular also for modernizing conventional dust filters, for example described in DE 44 40 279 Al. These dust-filters can be converted in a simple way by the filter hoses present singly in each case being replaced by compact groups of considerably smaller filter elements.

Conversion of the cleaning device is carried out in a similar way, by the large, Coanda V :\shnonnieNlSpeW'kOMC 2003 233229 15sop08 doc 03 028 4 nozzle used in the existing plants being replaced by the injectors of high efficiency according to the invention originating from a common distribution chamber.

The filter element used is preferably inherently stable filter bodies with a sufficient mechanical strength to absorb the differential pressure prevailing in the operating state between the dust chamber and clean air chamber. Such filter elements need no additional supporting elements or supporting baskets in the interior. The filter materials used can be those with specific surfaces and according to the functional principle of surface filtration, for example filter membranes, filter layers or micro fibers. Advantages of these materials are a low residual dust content, excellent filtration and cleaning properties, low energy consumption during the filtration as a result of lower differential pressures, low energy consumption as a result of lower pressures during the blow-off regeneration, and a longer period of use as a result of the filter bodies behaving substantially rigidly.

One refinement of the cleaning device according to the invention proposes that the distribution chamber be round or that the distribution chamber be formed as an annular duct. The form of this circular disk or of the annular duct substantially follows the arrangement of the individual filter elements which are combined into a group. In this case, the injectors are preferably arranged distributed uniformly over the length or the periphery of the distribution chamber, so that the result is an optimal alignment in the direction of the outlet openings of the filter elements arranged underneath: A further refinement proposes that the distribution chamber be connected to the compressed air lines via two transfer openings which are opposite each other in 03 028 5 relation to the centre of the distribution chamber. By using the two transfer openings, the distribution of the compressed air in the distribution chamber which is uniform and has low flow losses is achieved.

Furthermore, it is proposed that the axes of the injectors arranged at the bottom of the distribution chamber be located so as to align with the mid-axes of the filter elements of the group.

The injectors are preferably openings in the bottom of the distribution chamber. This permits particularly inexpensive production of the injectors without additional components. It is advantageous if the edges around the openings are provided with quarter-circle rounded portions, which are shaped out of the material of the bottom of the distribution chamber. The production of the injectors shaped in this way is preferably carried out by shaping the material of the bottom of the distribution chamber by means of appropriate punching devices or pressure stamps.

A further refinement proposes that the distribution chamber be arranged underneath the compressed air line and that the compressed air reach the distribution chamber from above. This permits low-loss flow guidance without deflection losses worth mentioning.

In order to fix the distribution chamber under the compressed air line, use can be made of retaining means which pull the distribution chamber against the compressed air line from underneath and in this way fix it to the compressed air line.

According to a preferred refinement, these retaining means are -angled pieces which can be screwed against the compressed air line, the angled pieces being supported from below by one leg against the compressed air line and from below by another leg against the distribution chamber. This achieves a fixing of the 03 028 6 distribution chamber to the underside of a compressed airline that is already present which is simple and also particularly economical within the context of a retrofit.

For the purpose of improved fixing, it is further proposed that the supporting faces of the legs supported against the compressed air line have a contour which is the same as the contour of the underside of the compressed air line.

Further details and advantages of the invention emerge from the following description of the associated drawing, in which an exemplary embodiment of a dust filter having a cleaning device is illustrated. In the drawing: fig. 1 shows a longitudinal section through a dust filter having a cleaning device according to the invention; fig. 2 shows a cleaning device above a group of filter elements of the dust filter, in a perspective illustration; fig. 3 shows the subjects according to fig. 2 but illustrated in a partial section, and fig. 4 shows the perspective view of the cleaning device obliquely from below.

A dust filter illustrated in an overall view in fig. 1 comprises a vertically aligned, cylindrical filter housing 1, which is subdivided by a horizontal dividing plate 2 into a dusty gas chamber 3 located at the bottom and a clean gas chamber 4 located at the top.

The dividing plate 2 is configured in a manner similar to a tube plate and has a plurality of openings with elongated filter elements inserted therein. The filter 03 028 7 elements illustrated are filter tubes 5, which are closed at their bottom end and are open at their top end. At their top open end, a plurality of the filter tubes 5 are provided with a common annular flange 6, by using which the filter tubes 5 are suspended from above in the openings of the dividing plate 2, the flange 6 being supported on the upper side of the dividing plate 2. The effective filter area is formed by the circumferential area of the filter tubes 5, which are cylindrical in the exemplary embodiment.

In each case a plurality of filter tubes 5 is arranged in relation to one another by means of the flange 6 such that they form a group or a filter bundle 7. In the exemplary embodiment illustrated, in each case five filter tubes 5 form such a group, the distance between the individual filter tubes 5 of each filter bundle 7 being smaller than the distance of the individual filter bundles 7 from one another.

In the region of the bottom end of the filter tubes on the outer side of the filter housing 1, there is arranged an annular duct 8, in which a dusty air supply duct 9 opens in order to supply the dust-containing air.

In order to clean and therefore regenerate the individual filter tubes 5 by means of compressed air, compressed air sources of a compressed air pulse injector system are arranged in the clean air chamber 4 above the filter bundles 7. The compressed air sources ensure that the dust or dust-containing product filtered out on the outer surfaces of the filter tubes during the filtration process is cleaned off said filter tubes 5. The compressed air reaches injectors via horizontal compressed air lines 11, flows out of these injectors and in this way passes into the openings in 15 of the individual filter tubes 03 028 8 Details of the cleaning device described generally above will be explained below by using figures 2, 3 and 4.

The compressed air lines 11, of which a plurality extend in parallel and horizontally in the clean air chamber 4, are guided such that the compressed air lines 11 exactly intersects the mid-axis of the group formed by the filter bundle 7. Fixed underneath the compressed air lines 11 is a distribution chamber 12 which, in the exemplary embodiment, has the shape of a flat annular duct. The diameter of the annular distribution chamber 12 is chosen such that the imaginary extensions of the longitudinal axes of the filter elements or filter tubes 5 pass through the distribution chamber 12.

In particular, fig. 4 reveals in a perspective view obliquely from below that a plurality of openings are arranged distributed over the flat bottom 13 of the distribution chamber 12 as injectors 14. These openings or injectors 14 are aligned in such a way that they lie exactly on the same axis as the mid-axis of the individual filter tubes 5. The compressed air emerging vertically downward from the injectors 14 therefore passes directly and on the shortest path into the respectively associated outlet opening 15 of the respective filter tube 5. Since the group of filter elements comprises five filter tubes 5, the number of injectors 14 in the bottom of the distribution chamber 12 is also five.

Fig. 3 reveals, as a sectional illustration, that the round distribution chamber 12 is connected to the compressed- air line 11 via transfer openings 16. In this case, each distribution chamber 12 is provided with a total of two transfer openings 16, which are opposite each other in relation to the centre of the distribution chamber 12. By means of this arrangement 03 028 9 of two transfer openings 16, a uniform distribution of the compressed air flowing into the interior of the distribution chamber 12 via the compressed air line 11 is achieved.

The transfer openings 16 are preferably provided with smooth rounded portions 17, in order also to this extent to keep the flow losses low.

The cleaning device may be retrofitted in a straightforward manner to dust filters that are already present. For this purpose, the compressed air lines 11 which are already present in the dust filters to be retrofitted are provided on the underside with threaded pins 18, which are preferably welded to the compressed air line 11. Retaining means in the shape of angled pieces 19 are placed on the threaded pins 18. The angled pieces 19 are supported from below against the compressed air line 11 by a vertical leg 20 and from below against the bottom 13 of the distribution chamber 12 by a horizontal leg 21, as soon as a nut 22 is screwed onto the threaded pins 18 and is tightened against the leg 21. For this purpose, the leg 21 is provided with a hole, through which the threaded pin 18 passes.

According to fig. 4, the supporting faces 23 of the legs 20 supported against the compressed air line 11 have a contour which is the same as the circular contour of the underside of the compressed air line 11.

Fig. 3 reveals that the injectors 14 are openings in the bottom 13 of the distribution chamber 12. The edges around the openings are provided with quartercircle rounded portions. The production of the injectors shaped in this way is preferably carried out by shaping the material of the bottom of the distribution chamber 12 by means of appropriate punching devices or pressure stamps. As a result of 03 028 the rounded edges, the compressed air can flow out of the distribution chamber 12 with low flow losses.

Fig. 2 reveals that the flange 6, which at the same time accommodates an entire filter bundle 7, is fixed to the dividing plate 2 by retaining means which are comparable with the retaining means 19 for the cleaning device. This makes it easier to subsequently convert the filter elements by replacing single, relatively long and voluminous filter hoses by the filter bundles illustrated, which have a smaller diameter and are substantially more compact.

03 028 -11 List of designations 1 Filter housing 2 Dividing plate 3 Dusty air chamber 4 Clean air chamber Filter tube 6 Flange 7 Filter bundle, group of filter elements 8 Annular duct 9 Dusty air supply duct 11 Compressed air line 12 Distribution chamber 13 Bottom 14 Injector Outlet opening 16 Transfer opening 17 Rounded portion 18 Threaded pin 19 Angled piece Leg 21 Leg 22 Nut 23 Supporting face

Claims

2. The cleaning device as claimed in claim 1 wherein the distribution chamber is formed as an annular duct.
3. The cleaning device as claimed in claim 2 wherein the injectors are arranged distributed uniformly over the length of the periphery of the distribution chamber.
4. The cleaning device as claimed in any one of the preceding claims, wherein the distribution chamber is connected to the compressed air line via two transfer openings, which are opposite each other in relation to the centre of the distribution chamber. The cleaning device as claimed in one of the preceding claims, wherein the air outlet axes of the injectors arranged on the bottom of the distribution chamber are aligned with the mid-axes of the filter elements of the group.
6. The cleaning device as claimed in one of claims 2 to 5, wherein the distribution chamber has the shape of an annular disk.
7. The cleaning device as claimed in one of the preceding claims, wherein the injectors are openings in the bottom of the distribution chamber.
8. The cleaning device as claimed in claim 7, wherein the edges around the openings are provided with quarter-circle rounded portions, which are shaped out of the material of the bottom of the distribution chamber. V:WronaDaneopSpdcDMC 2003 233229 15opOO 00
9. The cleaning device as claimed in one of the preceding claims, wherein 0^ the distribution chamber is arranged under the compressed air line and the compressed air reaches the distribution chamber from above. The cleaning device as claimed in claim 9, including retaining means which pull the distribution chamber against the compressed air line from a underneath and in this way fix it to the compressed air line. S11. The cleaning device as claimed in claim 10, wherein the retaining means are angled pieces which can be screwed against the compressed air line and which are supported from below with one leg against the compressed 0 10 air line and from below by another leg against the distribution chamber.
12. The cleaning device as claimed in claim 11, wherein the supporting faces of the legs that are supported against the compressed air line have a contour which is the same as the contour of the underside of the compressed air line.
13. A cleaning device, substantially as herein before described with reference to any one of the accompanying drawings. V:\%hamn\OanelSpecDMC 2003 233229 15po08 doc