DK170287B1

DK170287B1 - Swivel damper for chimney

Info

Publication number: DK170287B1
Application number: DK079193A
Authority: DK
Inventors: Michael Pedersen
Original assignee: Steelcon Chimney Esbjerg A S
Priority date: 1993-07-02
Filing date: 1993-07-02
Publication date: 1995-07-24
Also published as: DK79193A; EP0706600A1; AU679082B2; DE69415808T2; ATE175465T1; DE69415808D1; DK79193D0; EP0706600B1; WO1995001490A1; AU7068794A

Abstract

A vibration damper for a chimney comprising a partly liquid-filled container which is positioned at the top of the chimney and in which a plurality of perforated plate members are secured, said plate members extending from the bottom of the container and upwardly in a manner such that the plate members divide the container into separate spaces which are in mutual flow communication via the perforations of the plate members, and which additionally comprises at least one substantially horizontal perforated plate member at the surface of the liquid. The resulting vibration damper, which has an inexpensive, relatively maintenance-free structure, has improved damping properties over the prior art.

Description

CC

DK 170287 B1DK 170287 B1

Den foreliggende opfindelse angår en svingningsdæmper til skorstene, omfattende en delvis væskefyldt beholder placeret ved skorstenens top, i hvilken beholder der er fastgjort et antal perforerede pladelegemer, som strækker 5 sig nedefra og opefter på en sådan måde, at pladelegemerne opdeler beholderen i rum, som står i indbyrdes strømningsmæssig forbindelse via pladelegemernes perforeringer.The present invention relates to a chimney vibration damper comprising a partially liquid-filled container located at the top of the chimney in which a plurality of perforated plate members extending from below and upwards are secured in such a way that the plate bodies divide the container into compartments which is interconnected through the perforations of the plate members.

10 I forbindelse med høje skorstene, specielt fritstående skorstene, opstår der ofte det problem, at vindens passage omkring skorstenen, f.eks. ved en cirkulær skorsten, medfører et vekslende trykfelt, der påvirker skorstenen med kræfter vinkelret på vindretningen. Dette kan medføre 15 ved specielle vindhastigheder, at der opstår et resonans-lasttilfælde, der kan føre til særdeles voldsomme tværsvingninger af skorstenen. Ud over at sådanne tværsving-ninger er ubehagelige, idet tværsvingningerne blandt andet kan initialisere støj ved rystelserne, kan de være 20 farlige for skorstenen, idet de kan føre til udmattelses-brud i skorstenens konstruktion og i ekstreme tilfælde kan føre til at dele af skorstenen vælter.In connection with high chimneys, especially free-standing chimneys, the problem often arises that the passage of the wind around the chimney, e.g. by a circular chimney, an alternating pressure field affecting the chimney with forces perpendicular to the wind direction. This can cause 15 at special wind speeds, that a resonance load case occurs which can lead to extremely violent cross-section of the chimney. In addition to such transverse oscillations being unpleasant, the intersections being able to initialize noise at the shaking, among other things, they can be dangerous to the chimney as they can lead to fatigue fractures in the structure of the chimney and in extreme cases can lead to parts of the chimney overturned.

Derfor benyttes det ofte, specielt i forbindelse med me-25 get slanke skorstene, at forsyne skorstenens top med en svingningsdæmper, som så at sige tapper den af vinden tilførte energi ud af skorstenen og omsætter den til varmeenergi, der frigives til omgivelserne.Therefore, it is often used, especially in connection with many slender chimneys, to supply the chimney top with a vibration damper which, so to speak, draws the energy supplied by the wind out of the chimney and converts it into heat energy released to the surroundings.

30 Der er igennem tiderne foreslået adskillige svingningsdæmpere til dette formål, hvoraf nogle baserer sig på det grundliggende princip at ophænge en fast masse friktionsmæssigt og fjedrende bevægeligt i forhold til skorstenens konstruktion, hvorved denne masse vil fungere som sving-35 ningsdæmper. Sådanne konstruktioner er relativt dyre og kræver jævnlig vedligeholdelse for at opretholde den ønskede dæmpningskarakteristik, idet de bevægelige frik- DK 170287 B1 2 tionselementer på grund af slid, vejrlig og lignende kan ændre f.eks. dæmpningskarakteristika.30 Several oscillation dampers have been proposed for this purpose, some of which are based on the basic principle of suspending a fixed mass of frictionally and resiliently movable relative to the structure of the chimney, whereby this mass will act as a vibration damper. Such designs are relatively expensive and require regular maintenance to maintain the desired damping characteristics, as the movable friction elements due to wear, weather and the like may change e.g. damping characteristics.

Derimod foreslås der ifølge tysk fremlæggelsesskrift 5 nr. 1227633 en svingningsdæmper til en skorsten, som baserer sig på det indledningsvis nævnte princip, hvor skorstenens top er forsynet med en beholder, hvori der er fastgjort et antal lodrette, perforerede pladelegemer, sådan at disse opdeler beholderen i separate rum, som 10 står i indbyrdes strømningsmæssig forbindelse via pladelegemernes perforeringer. Idet beholderen delvis er fyldt med en væske, fungerer svingningsdæmperen ved at væsken, når skorstenen sættes i svingninger, vil søge at strømme igennem perforeringerne på de i væsken neddyppede plade-15 legemer, hvorved der på grund af den opståede turbulens i væsken samt indre friktion afsættes energi i form af varme til konstruktionen og videre til omgivelserne. På denne måde er der opnået en svingningsdæmper til en skorsten, som er relativt vedligeholdelsesfri, idet sving-20 ningsdæmperen virker helt uden mekaniske føringer, fjedre, dæmpere osv.On the other hand, according to German Patent Specification 5 No. 1227633, a vibration damper for a chimney is proposed which is based on the principle mentioned in the preamble, wherein the chimney top is provided with a container in which a number of vertical, perforated plate members are fixed, so that they divide the container. in separate compartments, which 10 are interconnected through the perforations of the plate members. As the container is partially filled with a liquid, the vibration damper functions by the liquid, when the chimney is put into oscillations, will seek to flow through the perforations on the plate bodies immersed in the liquid, thereby, due to the turbulence in the liquid and internal friction. energy is allocated in the form of heat to the structure and on to the surroundings. In this way, a vibration damper has been obtained for a chimney which is relatively maintenance-free, the vibration damper operating completely without mechanical guides, springs, dampers, etc.

Den foreliggende opfindelse baserer sig på dette grundliggende princip ifølge tysk fremlæggelsesskrift 25 nr. 1227633 og er således en videreudvikling af dette.The present invention is based on this basic principle according to German Patent Publication 25 No. 1227633 and is thus a further development of this.

Det er hensigten med den foreliggende opfindelse, at angive en svingningsdæmper, som er enkel og billig at fremstille, og som udviser forbedrede egenskaber med hensyn 30 til dæmpning, specielt når svingninger initialiseres.It is the object of the present invention to provide a vibration damper which is simple and inexpensive to manufacture and exhibits improved damping properties, particularly when vibrations are initialized.

Dette opnås ved at svingningsdæmperen udformes som angivet i krav 1, idet den i beholderen indeholdte væskemængde ved hjælp af f.eks. et i hovedsagen vandret perforeret 35 pladelegeme ved væskens overflade forhindres i at bevæge sig frit opadtil i beholderen, sådan som det er tilfældet ifølge tysk fremlæggelsesskrift nr. 1227633.This is achieved by designing the vibration damper as claimed in claim 1, the amount of liquid contained in the container by means of e.g. a substantially horizontally perforated plate body at the surface of the liquid is prevented from moving freely upwards in the container, as is the case according to German Patent Specification No. 1227633.

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Derimod tvinges den i beholderen indeholdte væske ved skorstenens tværgående svingningsbevægelse til at strømme igennem perforeringer i såvel den vandrette plade.som i de perforerede pladelegemer, der strækker sig fra 5 beholderens bund og opefter. Hermed opnås der med et relativt lille forbrug af perforerede plader en god dæmpning, idet den vandrette plade primært dæmper de store lodrette bevægelser ved overfladen og de perforerede pladelegemer, som strækker sig fra beholderens bund og opef-10 ter, dæmper horisontale strømninger i væsken.By contrast, the liquid contained in the container is forced by the transverse oscillation movement of the chimney to flow through perforations in both the horizontal plate and in the perforated plate members extending from the bottom of the container upwards. Hereby, with a relatively small consumption of perforated plates, good damping is obtained, with the horizontal plate primarily attenuating the large vertical movements at the surface and the perforated plate bodies extending from the bottom and up of the container, damping horizontal flows in the liquid.

Fra tysk fremlæggelsesskrift nr. 1275759 er det i denne forbindelse kendt at forsyne svingningsdæmpere til skorstene med vandrette plader, som er neddykket i en væske i 15 dæmperbeholderen. Der benyttes her et flertal af plader, som fortrinsvis er koncentreret ved beholderens bund, hvorved der opnås en dæmpning ved friktion hidrørende fra væskens horisontale strømning mellem pladerne. For at denne væskestrømning overhovedet kan finde sted, er pla-20 derne forsynet med huller, hvorved væsken kan undvige opadtil. Dette betyder i praksis at dæmpningseffekten øges jo større hullerne i de vandrette plader er, idet væsken alt andet lige vil strømme hurtigere. Hullerne i pladerne er derfor etableret med et helt andet formål og 25 med en helt anden effekt end perforeringerne i de vandrette plader ifølge den foreliggende opfindelse.From German Patent Specification No. 1275759 it is known in this connection to provide oscillation dampers for chimneys with horizontal plates immersed in a liquid in the damper container. Here, a plurality of plates are used, which are preferably concentrated at the bottom of the container, thereby obtaining a damping by friction resulting from the horizontal flow of the liquid between the plates. In order for this fluid flow to take place at all, the plates are provided with holes whereby the liquid can evade upwards. In practice, this means that the damping effect increases the larger the holes in the horizontal plates, since everything else will flow even faster. The holes in the plates are therefore established for a completely different purpose and with a completely different effect than the perforations in the horizontal plates according to the present invention.

Svigningsdæmperen ifølge opfindelsen kan omfatte et antal vandrette perforerede pladelegemer ved væskens overflade, 30 men i en hensigtsmæssig udførelsesform benyttes der alene én vandret perforeret plade ved væskens overflade, idet der ved hensigtsmæssig dimensionering af antallet af perforeringer i pladen samt perforeringernes areal kan opnås tilnærmelsesvis de samme dæmpningsegenskaber, som ved 35 brug af flere plader.The attenuator according to the invention may comprise a number of horizontal perforated plate bodies at the surface of the liquid, but in a suitable embodiment only one horizontal perforated plate is used at the surface of the liquid, whereby by appropriate dimensioning the number of perforations in the plate as well as the area of the perforations may be obtained. cushioning properties, as with multiple plates.

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Ved at den vandrette perforerede plade er placeret i eller under væskens overflade, som angivet i krav 3, opnås der en speciel god dæmpning, idet den væske, der befinder sig under pladen, er fuldstændig sikret imod frie lodret-5 te bevægelser, ud over strømning igennem perforeringerne i pladen.By placing the horizontal perforated plate in or below the surface of the liquid, as specified in claim 3, a particularly good damping is obtained, since the liquid located below the plate is completely protected against free vertical movements, in addition to flow through the perforations in the plate.

Ved at de fra beholderens bund forløbende plader strækker sig helt neden for den vandrette plade, sådan som det er 10 angivet i krav 4, udnyttes det samlede areal af de perforerede plader optimalt, samtidig med at der opnås en væsentlig produktionsmæssig fordel, idet pladerne kan fastgøres til hinanden på simpel måde og derved vil virke indbyrdes afstivende. Krav 5 og 6 angiver udførelsesfor-15 mer for opfindelsen, som er specielt produktionsvenlige, og med hvilke der opnås gode dæmpningsegenskaber i forhold til materialeforbruget for den samlede konstruktion.By extending the plates extending from the bottom of the container completely below the horizontal plate, as set forth in claim 4, the total area of the perforated plates is utilized optimally, while at the same time obtaining a significant production advantage, the plates being able to are attached to each other in a simple manner and thereby will act as a stiffener. Claims 5 and 6 specify embodiments of the invention which are particularly production-friendly and with which good damping properties are obtained in relation to the material consumption of the overall construction.

Opfindelsen beskrives nærmere i det følgende under hen-20 visning til tegningen, hvor: fig. 1 viser en skorsten med en svingningsdæmper placeret ved skorstenens top, set fra siden, 25 fig. 2 viser et vandret snit gennem en svigningsdæmper ifølge opfindelsen, set ovenfra, fig. 3 viser en svingningsdæmper set fra siden med et delvis udsnit, 30 fig. 4 viser en svingningsdæmper som i fig. 3, men i en alternativ udførelsesform.BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which 1 is a side view of a chimney with a vibration damper located at the top of the chimney; FIG. 2 is a plan view of a horizontal section through a deflection damper according to the invention; FIG. 3 is a side elevational attenuator, FIG. 4 shows a vibration damper as in FIG. 3, but in an alternative embodiment.

På fig. 1 vises således en skorsten 1 af en fritstående 35 type, dvs. at den alene understøttes ved fundamentet 3, som holder skorstenen oprejst. Skorstenen er forsynet med en indløbsåbning for røggasser 4 samt en udløbsåbning el- h DK 170287 B1 5 ler top 2. Den viste skorsten er udført i stålplader med et cirkulært tværsnit. Ved skorstenens top 2 er der på kendt vis indrettet en svingningsdæmper 5 ifølge opfindelsen, og denne svingningsdæmper 5 kan enten være monte-5 ret direkte på skorstenen som en sammenbygget enhed, eller den kan udgøres af en selvstændig enhed, som efterfølgende kan monteres på f.eks. eksisterende skorstene, som allerede er i brug. Hovedsagen er, at svingningsdæmperen 5 er relativt stift forbundet med skorstenens 1 10 konstruktion, således at svingninger i skorstenen, eventuelt hidrørende fra vindpåvirkninger, overføres direkte til svingningsdæmperen.In FIG. 1 shows a chimney 1 of a freestanding type, i.e. that it is supported only by the foundation 3 which holds the chimney upright. The chimney is provided with an inlet opening for flue gases 4 as well as an outlet opening or h. DK 170287 B1 5 or top 2. The chimney shown is made of steel plates with a circular cross section. At the top 2 of the chimney, a vibration damper 5 according to the invention is arranged, and this vibration damper 5 can either be mounted directly on the chimney as a built-in unit, or it can be constituted by an independent unit which can subsequently be mounted on the chimney. .g. existing chimneys that are already in use. The main thing is that the vibration damper 5 is relatively rigidly connected to the structure of the chimney 1 10, so that fluctuations in the chimney, possibly due to wind effects, are transmitted directly to the vibration damper.

Svingningsdæmperen 5 kan principielt placeres på et hvil-15 ket som helst sted på skorstenen 1, men det er klart, at den dæmpende effekt opnås bedst, når svingningsdæmperen 5 er placeret på skorstenen 1, der hvor svingningsamplituden på skorstenen 1 er størst. Dvs. ved skorstenens 1 top 2.The oscillator 5 can, in principle, be placed at any location on chimney 1, but it is clear that the attenuating effect is best achieved when the oscillator 5 is located on chimney 1, where the oscillation amplitude of chimney 1 is greatest. Ie at chimney 1 top 2.

20 På fig. 2 ses en snittegning af svingningsdæmperen 5 på fig. 1, set ovenfra. Som det ses afgrænser ydervæggen 6 og indervæggen 7 en beholder, hvori der er placeret en vandret liggende cirkulær plade 8 med perforeringer, og 25 hvor der langs hele omkredsen er placeret radialt forløbende lodretstående perforerede plader 9a, 9b, 9c.20 In FIG. 2 is a sectional view of the vibration damper 5 of FIG. 1, viewed from above. As can be seen, the outer wall 6 and the inner wall 7 define a container in which is placed a horizontal circular plate 8 with perforations, and 25 where radially extending perpendicular plates 9a, 9b, 9c are located along the entire circumference.

Svingningsdæmperens beholder afgrænses opadtil, som det ses på fig. 3 af en plade 10 og nedadtil af en tilsvaren-30 de plade 11. De lodretstående radialt forløbende plader 9a, 9b, 9c forløber, som det ses på figuren, fra beholderens bundplade 11 og op til den vandrette perforerede dæmpningsplade 8, og som det ses på figuren er beholderen fyldt delvis op med en væske, hvor væskestanden er indi-35 keret ved 12. Heraf ses det, at såvel de lodrette dæmpningsplader 9a, 9b, 9c som den vandrette dæmpningsplade 8 er totalt neddykket i væsken, når væsken er stillestå- ' DK 170287 B1 6 ende.The container of the vibration damper is bounded upwards, as seen in FIG. 3 of a plate 10 and downwards of a corresponding plate 11. The vertically extending radially extending plates 9a, 9b, 9c extend, as seen in the figure, from the bottom plate 11 of the container up to the horizontal perforated damping plate 8, and as the As can be seen in the figure, the container is partially filled with a liquid in which the liquid level is indicated at 12. From this it is seen that both the vertical damping plates 9a, 9b, 9c and the horizontal damping plate 8 are totally submerged in the liquid when the liquid is stationary end.

I en situation hvor beholderen påvirker en svingningsbevægelse fra skorstenen 1, vil den i beholderen indeholdte 5 væske som følge heraf begynde at strømme frem og tilbage i beholderen. Derved tvinges væske i beholderens nedre del primært igennem perforeringerne på de lodrette plader, og væsken i beholderens øverste del, dvs. ved væskeoverfladen 12, vil tvinges igennem den vandretliggende 10 perforerede plade 8. Det er af ovenstående klart, at selv om det er muligt at opnå dæmpningseffekt ved brug af vandrette perforerede plader i væskens nederste lag og f.eks. lodrette perforerede plader i væskens øvre lag, opnås der en optimal udnyttelse af dæmpningspladernes 15 areal, såfremt de vandrette dæmpningsplader 8 placeres nær ved væskeoverfladen 12, og de lodrette dæmpningsplader 9a, 9b, 9c placeres under den vandrette plade 8. Som det ses i fig. 4, kan der eventuelt benyttes flere - her er der vist to - vandrette dæmpningsplader 8a, 8b, som i 20 henhold til opfindelsens idé er placeret relativt tæt på hinanden ved væskeoverfladen 12. I en ikke vist udførelsesform kan de lodretgående dæmpningsplader 9a, 9b, 9c eksempelvis forløbe hele vejen langs beholderens bund 11 til beholderens top 10. Det foretrækkes dog, at disse 25 lodretstående plader 9a, 9b, 9c fortrinsvis forløber nedenfor de vandrette plader 8, idet der hermed opnås en optimal udnyttelse af pladernes areal.Consequently, in a situation where the container affects a pivotal movement from the chimney 1, the liquid contained in the container will start to flow back and forth in the container. Thereby liquid in the lower part of the container is forced primarily through the perforations on the vertical plates, and the liquid in the upper part of the container, ie. at the liquid surface 12, will be forced through the horizontal perforated plate 8. It is clear from the above that although it is possible to achieve damping effect by using horizontal perforated plates in the lower layer of the liquid and e.g. perpendicular perforated plates in the upper layer of the liquid, an optimal utilization of the area of the damping plates 15 is obtained if the horizontal damping plates 8 are placed near the liquid surface 12 and the vertical damping plates 9a, 9b, 9c are placed below the horizontal plate 8. As can be seen in FIG. . 4, there may optionally be used several - here are shown two - horizontal damping plates 8a, 8b, which according to the idea of the invention are located relatively close to each other at the liquid surface 12. In a not shown embodiment, the vertical damping plates 9a, 9b, 9c, for example, extend all the way along the bottom 11 of the container to the top of the container 10. However, it is preferred that these vertical plates 9a, 9b, 9c preferably extend below the horizontal plates 8, thereby obtaining an optimal utilization of the area of the plates.

Selv om der kan opnås rimelige dæmpningseffekter ved 30 placering af de vandrette plader 8 i en lille afstand over væskeoverfladen 12, foretrækkes det dog, at de vandrette plader 8 er let neddykket i væsken, sådan som det ses i fig. 3 og 4, hvorved det opnås at den væske, som indeholdes eller indelukkes mellem bundpladen 11 og de 35 vandrette dæmpningsplader 8, tvinges til at strømme gen-nem perforeringerne i pladerne fremfor at foretage frie skvulpende bevægelser, sådan som det er tilfældet, hvis 7 DK 170287 B1 ikke de vandrette plader 8 er neddykket i væsken.However, although reasonable damping effects can be obtained by placing the horizontal plates 8 at a small distance above the liquid surface 12, it is preferred that the horizontal plates 8 be slightly submerged in the liquid, as seen in FIG. 3 and 4, whereby the liquid contained or enclosed between the base plate 11 and the 35 horizontal damping plates 8 is forced to flow through the perforations in the plates rather than making free swirling movements, as is the case if 7 The horizontal plates 8 are not immersed in the liquid.

Afhængig af den givne skorstenskonstruktion 1, som ønskes dæmpet, er det klart at dæmpningsegenskaberne for sving-5 ningsdæmperen 5 skal kunne tilpasses det aktuelle formål. Konstruktionen ifølge opfindelsen giver rige muligheder for at variere forskellige parametre med henblik på at opnå den optimale dæmpning til en given konstruktion. Der kan således varieres på antallet af dæmperplader og på 10 antallet af perforeringer og arealet af perforeringerne i pladerne. Således vil en forøgelse af antallet af plader, en reduktion i antallet af perforeringer eller reduktion af perforeringernes areal, medføre større strømningsmodstand og dermed større dæmpning, alt andet lige. Derud-15 over vil beholderens samlede volumen samt væskens viskositet også influere på svingningsdæmperens dæmpningskarakteristika. Med henblik på at sikre at svingningsdæmperen virker optimalt under forskellige vejrforhold, er det blandt andet af denne grund vigtigt, at den i beholderen 20 indeholdte dæmpningsvæske er frostsikker og har en viskositet, som er relativt uafhængig af væskens temperatur.Depending on the given chimney structure 1 which is desired to be dampened, it is clear that the damping characteristics of the vibration damper 5 must be adaptable to the current purpose. The construction according to the invention provides ample opportunities to vary various parameters in order to obtain the optimal damping for a given construction. Thus, the number of damper plates and the number of perforations and the area of perforations in the plates can be varied. Thus, an increase in the number of plates, a reduction in the number of perforations or a reduction in the area of the perforations will result in greater flow resistance and thus greater damping, all else being equal. In addition, the total volume of the container as well as the viscosity of the liquid will also influence the damping characteristics of the vibration damper. In order to ensure that the vibration damper works optimally under different weather conditions, it is important for this reason, among other things, that the damping liquid contained in the container 20 is frost-proof and has a viscosity which is relatively independent of the temperature of the liquid.

Den ovenfor anførte udførelsesform for opfindelsen, er specielt indrettet til brug i forbindelse med skorstene 25 med cirkulært tværsnit, men det er klart, at opfindelsens grundliggende idé kan overføres til andre typer af skorstene, f.eks. med firkantede og ovale tværsnit. Derudover er der for fagmanden righoldige muligheder for brug af forskellige materialer i konstruktionen. Således kan 30 dæmpningspladerne udgøres af simple metalplader med udstandsede huller eller en gitterplade.The above-mentioned embodiment of the invention is specifically designed for use in connection with chimneys 25 of circular cross section, but it is clear that the basic idea of the invention can be transferred to other types of chimneys, e.g. with square and oval cross sections. In addition, there are ample opportunities for the skilled person to use various materials in the construction. Thus, the damping plates may be formed of simple metal plates with protruding holes or a grid plate.

3535

Claims

A chimney oscillator comprising a partially liquid-filled container located at the top of the chimney, in which a plurality of perforated plate members extending downwardly and upwardly of the container is secured in such a way that the plate bodies divide the container into space in interconnected flow 10 via the perforations of the plate bodies, characterized by further comprising at least one substantially horizontal perforated plate body at the surface of the liquid.

A vibration damper according to claim 1, characterized in that it comprises only one horizontal perforated plate at the surface of the liquid.

A vibration damper according to claim 2, characterized in that the horizontal perforated plate is located in or below the surface of the liquid.

A vibration damper according to claim 2 or 3, characterized in that the perforated plates extending from below and upwards extend completely below the horizontal perforated plate.

A vibration damper according to one of the preceding claims, characterized in that the container is annular and extends around the chimney. 30

A vibration damper according to claim 5, characterized in that the extending perforated plates are approximately vertical and oriented radially with respect to the axis of the container. 35 i.

A vibration damper according to one of the preceding claims, characterized in that they extend downwards and upwards