DK170844B1

DK170844B1 - Condensate discharge device from a low flue gas chimney

Info

Publication number: DK170844B1
Application number: DK364989A
Authority: DK
Inventors: Walter Reuter; Reinhard Maennl
Original assignee: Schott Ruhrglas
Priority date: 1988-07-26
Filing date: 1989-07-24
Publication date: 1996-02-05
Also published as: DK364989A; ATE71210T1; EP0353528B1; DE58900661D1; DE8809519U1; DK364989D0; EP0353528A1

Abstract

Apparatus for evacuating the condensates (1) designed for a chimney (3) operating at a low flue gas temperature, characterised by an overflow container (4), a neutralisation cartridge (13) immersed from above in the liquid chamber (11) of the overflow container and a suspended matter filter (25) disposed in an upper section of the neutralisation cartridge (13), the apparatus being held together by a cover (35) which can be mounted on the overflow container (7), and the neutralisation cartridge (13) being mounted in a removable fashion in the overflow container (7) and the suspended matter filter (25) being mounted in a removable fashion at the upper edge (47) of the neutralisation cartridge (13).

Description

DK 170844 B1DK 170844 B1

Opfindelsen angår et apparat til bortledning og neutralisering af kondensat fra en med lav røggastemperatur arbejdende skorsten til et olie- eller gasfyret forbrændingsanlæg.The invention relates to an apparatus for draining and neutralizing condensate from a low-flue gas chimney to an oil or gas-fired combustion plant.

5 I moderne opvarmningsanlæg arbejdes fortrinsvis med lave røggastemperaturer. Ud over andre fordele fås herved den fordel, at sure bestanddele i røggassen ikke afgives til luften, men forekommer som kondensat. Behandlingen og bortledningen af sådanne kondensater kræver en vis plads 10 til indbygning og vedligeholdelse.5 In modern heating systems, preference is given to low flue gas temperatures. In addition to other advantages, the advantage is that acidic constituents in the flue gas are not released to the air, but appear as condensate. The processing and discharge of such condensates requires some space 10 for installation and maintenance.

DE-A-3 243 988 omtaler eksempelvis bortledning af kondensat via en indkoblet filterindretning, som er forsynet med en beholder, som indeholder et neutraliseringsmiddel, idet i det mindste neutraliseringsmidlet er udskifteligt.For example, DE-A-3 243 988 discloses condensate drainage via a switched-on filter device provided with a container containing a neutralizing agent, at least the neutralizing agent being interchangeable.

15 Beholderen er fortrinsvis udformet som udskiftningsbeholder og omfatter et volumen til en neutraliseringsmiddelmængde, som i det mindste rækker til en fyringsperiode. Med en sådan filterindretning kan kondensatet nok rent principielt neutraliseres, men de i kondensatet yderligere indeholdte flyve-20 stoffer kan føre til en for tidlig udtømning af virkningen af neutraliseringsmaterialet og forårsager derved eksempelvis hyppigere vedligeholdelsesintervaller for anlægget, højere vedligeholdelsesomkostninger og fører til en totalt mindre pålidelig funktionsmåde for apparatet til bortledning og 25 neutralisering af kondensat. Store vanskeligheder forårsages således af røggassens komplekse sammensætning.The container is preferably configured as a replacement container and comprises a volume of a neutralizing agent amount which at least extends to a firing period. With such a filter device, the condensate can be neutralized in principle, but the aerosols further contained in the condensate can lead to premature depletion of the effect of the neutralizing material, for example, causing more frequent maintenance intervals for the plant, higher maintenance costs and leads to a total less reliable operation of the apparatus for draining and neutralizing condensate. Thus, great difficulties are caused by the complex composition of the flue gas.

Det er formålet med opfindelsen at tilvejebringe et kondensatbortledningsapparat til en med lav røggastemperatur drevet skorsten, som fungerer pålideligt og kun kræver ringe 30 plads og udgifter til installation og vedligeholdelse.SUMMARY OF THE INVENTION It is an object of the invention to provide a condensate discharge apparatus for a low flue gas chimney which operates reliably and requires little space and installation and maintenance costs.

Dette er ifølge opfindelsen opnået med det i krav 1 definerede kondensatbortledningsapparat.This is achieved according to the invention with the condensate discharge apparatus as defined in claim 1.

Med apparatet ifølge opfindelsen forhindres forstyrrende overfyldning af neutraliseringsmaterialet med flyve-35 stoffer, såsom olie-, sod- og askepartikler, således at neutraliseringsmaterialet ikke for hurtigt bliver uvirksomt.The apparatus according to the invention prevents disruptive overflow of the neutralizing material with flying substances such as oil, soot and ash particles, so that the neutralization material does not become too inactive too quickly.

2 DK 170844 B12 DK 170844 B1

Ved den udtagelige anbringelse af flyvestoffilteret i neutraliseringspatronen fås en meget enkel konstruktion, hvor udtagning og udskiftning af flyvestoffilteret og/eller neutraliseringsmaterialet let kan udføres. Ved udskiftning af 5 filteret kan overfladen af neutraliseringsmaterialet desuden inspiceres.The removable placement of the flywheel filter in the neutralization cartridge provides a very simple construction, in which removal and replacement of the flywheel filter and / or neutralization material can be easily carried out. In addition, when replacing the filter, the surface of the neutralizing material can be inspected.

Flyvestoffilteret kan udføres forholdsvis lille, idet det kun skal optage bestanddele, som forekommer i forholdsvis ringe mængder i røggassen. Flyvestoffilteret kon-10 strueres hensigtsmæssigt således, at dets funktionstid svarer til skorstenens sædvanlige serviceintervaller. Herved kan der meget let sikres en korrekt bortskaffelse af affald. Da neutraliseringsmaterialet er beskyttet mod farlige og sundhedsskadelige stoffer af det foran indskudte flyvestof filter, 15 danner det brugte neutraliseringsmateriale et ufarligt affald, der ikke behøver at behandles som særskilt affald.The fly fabric filter can be made relatively small in that it only needs to absorb components that are present in relatively small amounts in the flue gas. The fly fabric filter is suitably constructed so that its operating time corresponds to the usual chimney service intervals. This can easily ensure proper disposal of waste. Since the neutralization material is protected against dangerous and harmful substances by the pre-inserted in-flight filter, the spent neutralizing material forms a harmless waste which does not need to be treated as separate waste.

Opfindelsen forklares nærmere i det følgende i forbindelse med en udførelsesform og under henvisning til tegningen.The invention is explained in more detail below in connection with an embodiment and with reference to the drawing.

20 Tegningen viser skematisk et vertikalt snit gennem en udførelsesform for et kondensatbortledningsapparat ifølge opfindelsen.The drawing schematically shows a vertical section through an embodiment of a condensate discharge apparatus according to the invention.

Det viste kondensatbortledningsapparat 1 tjener til bortledning af surt kondensat fra et forbrændingsanlægs 5 25 skorsten 3, som drives med forholdsvis lav røggastemperatur.The condensate wastewater apparatus 1 illustrated serves to dissipate acidic condensate from a combustion plant 5 25 chimney 3 which is operated at relatively low flue gas temperature.

Der kan her især være tale om husopvarmning med gas eller olie.In particular, this may be the case of house heating with gas or oil.

Apparatet 1 har en overløbsbeholder 7, som fortrinsvis er transparent og f.eks. kan bestå af plast. Overløbsbehol-30 deren 7 har i sin øverste del et overløb 9 for behandlet kondensat og danner et væskerum 11 neden under overløbet 9.The apparatus 1 has an overflow container 7 which is preferably transparent and e.g. may consist of plastic. The overflow container 7 has in its upper part an overflow 9 for treated condensate and forms a liquid space 11 below the overflow 9.

En neutraliseringspatron 13 er oppefra nedstukket i væskerummet 11. Patronens nederste ende er lukket med en væskegen-nemtrængelig væg 15, der er holdt i afstand fra en bund 17 35 i overløbsbeholderen 7. Den øverste ende af neutraliseringspatronen 13 kan forbindes med en kondensat-tilløbsledning 3 DK 170844 B1 19. Mellem sine to ender danner neutraliseringspatronen 13 et rum 21 til optagelse af et udskifteligt neutraliseringsmateriale 23, der forbruges under drift.A neutralization cartridge 13 is projected from above in the liquid chamber 11. The lower end of the cartridge is closed with a liquid-permeable wall 15 spaced from a bottom 17 35 in the overflow container 7. The upper end of the neutralization cartridge 13 can be connected to a condensate supply line. 3 Between its two ends, the neutralization cartridge 13 forms a space 21 for receiving an interchangeable neutralizing material 23 which is consumed during operation.

Neutraliseringspatronen 13 består fortrinsvis af 5 borsilikatglas og forener derved høj styrke, modstand mod kemiske angreb og transparens med lave fremstillingsomkostninger.The neutralization cartridge 13 preferably consists of 5 borosilicate glass, thereby combining high strength, resistance to chemical attack and transparency with low manufacturing costs.

Mellem kondensat-tilløbsledningen 19, der f.eks. er en fleksibel, syrefast plastslange, som er tæt forbundet 10 med den nederste ende af skorstenen 3, og rummet 21 i neutraliseringspatronen 13 er et udskifteligt flyvestoffilter 25 anbragt i et øverste afsnit af neutraliseringspatronen 13.Between the condensate supply line 19, e.g. is a flexible, acid-resistant plastic hose which is tightly connected to the lower end of the chimney 3, and the space 21 of the neutralization cartridge 13 is a replaceable flywheel filter 25 disposed in an upper portion of the neutralization cartridge 13.

I den viste udførelsesform har flyvestoffilteret 25 et hus 27, som danner et optagerum 29 for et flyvestoffilter-15 materiale 31, og som ved sin øverste ende har en øvre rand 33, der griber ind over en rand ved neutraliseringspatronens 13 øverste åbne ende og kan lukkes med et dæksel 35. Dækslet 3 5 har en tilgangsstuds 37 for kondensat-tilløbsledningen 19.In the illustrated embodiment, the flywheel filter 25 has a housing 27 which forms a take-up space 29 for a flywheel filter material 31 and which at its upper end has an upper edge 33 which engages a rim at the upper open end of the neutralization cartridge 13 and can is closed with a cover 35. The cover 35 has an inlet nozzle 37 for the condensate supply line 19.

Den væskegennemtrængelige væg 15 ved neutraliserings-20 patronens 13 nederste ende kan f.eks. bestå af en syrefast, porøs filterdug, porøst plast eller porøst glas. I den viste udførelsesform er anvendt en syrefast filterdug, som er lagt omkring en fremspringende nederste kant 39 af neutraliseringspatronen 13 og er fastgjort tætsluttende og aftageligt 25 ved hjælp af forbindelsesorganer 41, f.eks. en O-ring eller et gummibånd. Denne udformning er særligt enkel.The liquid-permeable wall 15 at the lower end of the neutralization cartridge 13 may e.g. consist of an acid-resistant, porous filter cloth, porous plastic or porous glass. In the embodiment shown, an acid-resistant filter cloth is used which is laid around a protruding lower edge 39 of the neutralization cartridge 13 and is tightly sealed and removable 25 by means of connecting means 41, e.g. an O-ring or a rubber band. This design is particularly simple.

Med den beskrevne konstruktion kan flyvestoffilteret 25 meget let udskiftes. Efter aftagning af dækslet 35 behøver man blot at udtage huset 27 af den øverste del af neutralise-30 ringspatronen 13 og erstatte det med et nyt flyvestof filter. Derefter skal dækslet 35 påsættes igen. Flyvestoffilteret er på grund af sin ringe højde og sin ringe fremstillingspris især tænkt anvendt til éngangsbrug og kan på sædvanlig måde fjernes som særligt affald. Det udtagne flyvestoffilter 25 35 kan naturligvis også tømmes og ifyldes nyt flyvestoffilterma-teriale 31. På grund af den dermed forbundne mulighed for 4 DK 170844 B1 ufaglig håndtering er dette imidlertid mindre tilrådeligt.With the construction described, the flywheel filter 25 can be easily replaced. After removing the cover 35, one simply needs to remove the housing 27 of the upper portion of the neutralization cartridge 13 and replace it with a new flywheel filter. Then cover 35 must be reattached. Due to its low height and low manufacturing cost, the fly fabric filter is intended to be used for single use only and can usually be removed as special waste. Of course, the removed fly filter 25 35 can also be emptied and filled with new fly filter material 31. Due to the associated possibility of unskilled handling, however, this is less advisable.

Dækslet 35 er fortrinsvis som vist fastgjort let aftageligt på et øverste kantparti 43 af overløbsbeholderen 7, hvorved det er anbragt på flyvestoffilterets 25 øverste 5 kant. Til udskiftning af flyvestoffilteret 25 såvel som til regenerering af neutraliseringspatronen 13 kræves så ingen andre foranstaltninger end aftagning og genpåsætning af dækslet 35.The cover 35 is preferably, as shown, affixed easily removable to an upper edge portion 43 of the overflow container 7, whereby it is disposed on the top 5 edge of the flywheel filter 25. Replacement of the flywheel filter 25 as well as regeneration of the neutralization cartridge 13 requires no other measures than removing and replacing the cover 35.

Dækslet 35 kan hensigtsmæssigt, som vist, fastgøres 10 til overløbsbeholderens 7 øverste kantparti 43 med en hurtig-lukkeforbindelse 45. Forbindelsen kan f.eks. udføres som en skrueforbindelse eller fortrinsvis som et snaplukke. I begge tilfælde går de ind over hinanden gribende omkredsrande af dækslet 35 og det øverste kantparti 43 i indgreb med hinan-15 den. Herved forenkles betjeningen yderligere.Conveniently, as shown, the cover 35 can be secured 10 to the upper edge portion 43 of the overflow container 7 with a fast-closing connection 45. The connection can e.g. is carried out as a screw joint or preferably as a snap closure. In both cases, the circumferential circumferential edges of the cover 35 and the upper edge portion 43 engage with each other. This further simplifies operation.

Det vil forstås, at der overalt efter behov kan anbringes tætningsringe, hvor der ønskes god tætning.It will be appreciated that sealing rings can be placed wherever required where good sealing is desired.

I den viste udførelsesform har neutraliseringspatronen 13 en radialt indadbøjet, øverste rand 47. Herved lettes 20 udtagning af neutraliseringspatronen 13, og flyvestoffilteret 25 centreres.In the illustrated embodiment, the neutralization cartridge 13 has a radially inwardly bent upper edge 47. This facilitates removal of the neutralization cartridge 13 and the fly fabric filter 25 is centered.

I den viste udførelsesform er der på dækslet 35 anbragt en med tilløbsstudsen 37 forbundet dykkerklokke 49, hvis bredeste ende ligger i en afstand under overløbsniveauet 25 51 under drift, som svarer til det i skorstenen 3 herskende overtryk, f.eks. 10 mm VS, plus en sikkerhedsafstand, f.eks.In the embodiment shown, a diving bell 49 connected to the inlet nozzle 37 is provided, the widest end of which is at a distance below the overflow level 25 51 during operation which corresponds to the overpressure prevailing in the chimney 3, e.g. 10 mm VS, plus a safety distance, e.g.

40 mm VS. Dette bevirker under drift en gastæt lukning mellem skorstenen 3 og tilløbet 19 på den ene side og overløbet 9 for spildevandet på den anden side.40 mm VS. During operation, this causes a gas-tight closure between the chimney 3 and the inlet 19 on one side and the overflow 9 for the waste water on the other side.

30 Dykkerklokken 49 har den fordel, at den ved sin øver ste, smalleste ende let kan danne en fejlfri tætning mod tilløbsstudsen 37 og kondensat-tilførselsledningen 19, så fuldstændig tætning mellem dækslet 35, overløbsbeholderen 7 og de øverste rande af neutraliseringspatronen 13 og flyve-35 stoffilteret 25 ikke er afgørende.The diving bell 49 has the advantage that at its upper, narrowest end it can easily form a flawless seal against the inlet nozzle 37 and the condensate supply line 19, then complete sealing between the cover 35, the overflow container 7, and the upper edges of the neutralization cartridge 13 and the airplane. 35 the fabric filter 25 is not essential.

Flyvestoffiltermaterialet 31 er fortrinsvis, som DK 170844 B1 5 vist, anbragt under den største, nederste ende af dykkerklokken 49. Herved fås en ensartet tilførsel til flyvestof-filtermaterialet 31 af det fra dykkerklokken 49 kommende kondensat.Preferably, as shown in DK 170844 B1 5, the fly fabric filter material 31 is placed below the largest, lower end of the diver bell 49. This provides a uniform supply to the fly dust filter material 31 of the condensate coming from the diver bell 49.

5 Dykkerklokken 49 består fortrinsvis af borsilikatglas.The diving bell 49 preferably consists of borosilicate glass.

Dette materiale er økonomisk, holdbart og transparent.This material is economical, durable and transparent.

Tilslutningsstudsen 37 er fortrinsvis udført let aftagelig, så anordningen om nødvendigt bekvemt kan skilles, f.eks. af hensyn til rengøring. På tegningen er forbindelsen 10 vist som en forskruning.The connecting plug 37 is preferably made easily removable so that the device can be conveniently separated, e.g. for the sake of cleaning. In the drawing, the connection 10 is shown as a bolt.

I den viste udførelsesform er neutraliseringspatronen 13 anbragt udtagelig i en holdeindretning 53 i overløbsbeholderen 7, således at den kan på- og afmonteres let uden brug af værktøj. Holdeindretningen 53 er her vist som en trinvis 15 udformning af bunden 17 i overløbsbeholderen 7. Den kan let fremstilles, især når overløbsbeholderen er af plast. I en anden udførelsesform består holdeindretningen 53 af indlagte plastdele.In the embodiment shown, the neutralization cartridge 13 is removably placed in a holding device 53 in the overflow container 7, so that it can be easily mounted and removed without the use of tools. The holding device 53 is shown here as a stepwise configuration of the bottom 17 of the overflow container 7. It can be easily manufactured, especially when the overflow container is of plastic. In another embodiment, the holding device 53 consists of inset plastic parts.

Rummet 21 i neutraliseringspatronen 13 er fyldt med 20 en blanding af neutraliseringsroaterialet 23, f.eks. M6K Ilgranulat fra firmaet Cillichemie, og et inert løsnemateriale 55.The space 21 of the neutralization cartridge 13 is filled with 20 a mixture of the neutralization material 23, e.g. M6K Ilgranulate from the company Cillichemie, and an inert solvent 55.

Herved kan sammenbagning af det af neutraliseringsmaterialet og kondensatet opstående reaktionsprodukt undgås.Hereby baking of the reaction product formed by the neutralizing material and the condensate can be avoided.

25 Det er især fordelagtigt, at neutraliseringsmaterialet 23 består af CaC03. Herved fås som reaktionsprodukt uskadelige kalciumsalte, f.eks. CaS04, og den ved reaktionen dannede kuldioxid virker løsnende. Det er så fordelagtigt at tilvejebringe en tilstrækkelig gasudstrømningsvej til overløbet 30 9 i det øverste område af neutraliseringspatronen 13, f.eks.It is particularly advantageous that the neutralizing material 23 consists of CaCO 3. Thus, as a reaction product, harmless calcium salts are obtained, e.g. CaSO 4 and the carbon dioxide formed by the reaction appear to be loosening. It is then advantageous to provide a sufficient gas outflow path to the overflow 30 9 in the upper region of the neutralization cartridge 13, e.g.

i form af en tilsigtet utæthed mellem dækslet 35 og de øverste rande af neutraliseringspatronen 13 og fly vestof filterets hus 27. Som løsnemateriale anvendes fortrinsvis brudstykker af glasrør, især af borsil ikatglas. I så fald er en andel 35 på ca. 10 vægt% løsnemateriale tilstrækkelig. F.eks. kan anføres: rørbrudstykker med indvendig diameter I = 5-10 mm, DK 170844 B1 6 vægtykkelse WD = 0,5-1,0 mm, længde L = 5-10 mm.in the form of an intended leakage between the cover 35 and the upper edges of the neutralizing cartridge 13 and the airplane west of the filter housing 27. Preferably, as loose material, fragments of glass tubes, especially borosilicate glass, are used. In this case, a share of 35 is approx. 10% by weight of soluble material. For example. can be specified: pipe breakers with internal diameter I = 5-10 mm, DK 170844 B1 6 wall thickness WD = 0.5-1.0 mm, length L = 5-10 mm.

Den viste anordning arbejder efter syfonprincippet uden pumpe og mekanisk bevægede dele, alene ved tyngdekraftens påvirkning. Ved start kan vand påfyldes op til overløbet 5 9. Under drift behandles det tilløbende kondensat i to trin.The device shown works according to the principle of the siphon without pump and mechanically moving parts, only under the influence of gravity. At start-up, water can be filled up to overflow 5 9. During operation, the running condensate is treated in two stages.

Først tilbageholdes farlige og forstyrrende flyvestoffer, såsom oliedråber, sodpartikler, askepartikler og lignende, i flyvestoffilteret 25. Afhængigt af det anvendte flyvestof-f iltermateriale 31 kan flyvestof filteret 25 også tilbageholde 10 røggassens stærkt giftige bestanddele, som kun forekommer i ringe mængder, f.eks. kræftfremkaldende, flerkemede kulbrintestoffer.First, hazardous and disruptive liquids, such as oil droplets, soot particles, ash particles, and the like, are retained in the liquid filter 25. Depending on the liquid filter material used 31, the liquid filter 25 may also retain the highly toxic constituents of the flue gas, which occur only in small amounts, f. eg. carcinogenic, multicomponent hydrocarbons.

Det på denne måde forrensede kondensat flyder langsomt gennem neutraliseringsmaterialet 23 og efter neutralisering 15 ud gennem overløbet 9.The condensate thus purified flows slowly through the neutralization material 23 and after neutralization 15 out through the overflow 9.

Anordningen er fortrinsvis beregnet til, at neutraliseringsmaterialet skal kunne holde i flere måneder, f.eks. ca. 12 måneder. Dette er f.eks. muligt med passende dimensionering ved de kondensatmængder, som forekommer i opvarm-20 ningsanlæg i privathuse. Anskaffelses- og drifts- og vedligeholdelsesudgifterne hertil er rimelige.The device is preferably intended for the neutralization material to last for several months, e.g. ca. 12 months. This is e.g. possible with suitable sizing in the quantities of condensate present in heating systems in private houses. The acquisition and operating and maintenance costs thereof are reasonable.

25 30 3525 30 35

Claims

An apparatus (1) for draining condensate from a combustion plant (5) chimney (3) operating at low flue gas temperature, with a neutralization cartridge (13) for the 5 condensate to be treated, comprising a lower end and an open a top end which can be connected to a condensate supply line, a receiving tube (21) for a replaceable neutralizing material (23) consumed during operation, formed between the ends, characterized in that - the neutralization cartridge (13) protrudes into a preferably transparent overflow container (7) comprising in the upper part a treated condensate overflow (9) and under the overflow (9) forming a liquid compartment (11), the neutralization cartridge (13) having at its lower end a liquid-permeable wall (15) ) and are spaced from the bottom (17) of the overflow container (7) and - between the condensate supply line (19) and the receptacle (21), an interchangeably located in the upper section of the neutralization cartridge (13) is arranged. fly fabric filter (25).

Apparatus according to claim 1, characterized in that the fly fabric filter (25) comprises a housing (27) which forms a take-up space (29) for fly filter material (31) and which has at its upper end an upper edge engaging 2. over an edge at the upper open end of the neutralization cartridge (13) and can be closed with a removable cover (35) which includes an inlet plug (37) for the condensate supply line (19).

Apparatus as claimed in claim 1 or 2, characterized in that the cover (35) is easily removably secured to an upper edge portion (43) of the overflow container (7) with a quick-release closure, being mounted on the upper edge of the flywheel filter. housing (27).

Apparatus according to claim 3, characterized in that the quick-release closure is a snap-closure or a screw connection. DK 170844 B1

Apparatus according to claims 2-4, characterized in that the neutralization cartridge (13) has a radially curved upper edge (47).

Apparatus according to Claims 2 to 5, characterized in that the cover (35) has a glass dive bell (49) tightly sealed to the inlet connection (37) with a largest lower end below the liquid level of the fly filter (25). (51) in operation.

Apparatus according to claim 6, characterized in that the flywheel filter material (31) is arranged below the largest end of the diving bell (49).

Apparatus according to one of Claims 6 or 7, characterized in that the inlet connector (37) is easily detachable and the diver clock (49) is releasably fastened to the inlet connector (37) at its minimum end.

Apparatus according to any one of the preceding claims, characterized in that the neutralization cartridge (13) consists of glass and is removably inserted into a holding device (53) in the overflow container (7).

Apparatus according to any one of the preceding claims, characterized in that the take-up space (21) of the neutralizing cartridge (13) is filled with a mixture of a neutralizing material (23) and an inert solvent material (55).

Apparatus according to any one of the preceding claims, characterized in that the neutralization cartridge (13) and the flywheel filter (25) are dimensioned for a function time corresponding to a normal chimney service interval (3). 30 35