EP1369642B1 - Actively insulated chimney, in particular steel chimney - Google Patents

Description

The present invention relates to a chimney according to the preamble of claim 1.

It has long been known to provide in double-shell chimneys with a flue gas leading inner tube and a chimney outward outer sheath between the outer casing and the inner tube insulation materials, on the one hand overheating of adjacent components, especially in an emergency at a burnout of the fireplace, and on the other hand, in normal operation to avoid excessive cooling of the flue gas, especially at the chimney head. The maintenance of a certain minimum temperature is required for two reasons. On the one hand, a lowering of the flue gas temperature below a certain dew point would lead to the formation of moisture in the chimney with subsequent Durchfeuchtungs- and Versottungserscheinungen, especially by the aggressive constituents of the flue gases, such as sulfur dioxide, aggressive substances may arise. In addition, a dew point can lead, especially on the outside or on the inner surface of the outer casing and in the insulating layer to the formation of moisture, which can result in a loss of insulation effect, for example, when a dampening of the insulating layer. On the other hand, an excessive cooling of the flue gas in the chimney head would mean that the withdrawal of flue gases from the chimney would no longer be guaranteed. It would not be possible to maintain the so-called "train".

To overcome these problems, various solutions are known in the art. So it is for example from the DE 3211536 A1 , of the DE 3151327 A1 and the CH 614990 A5 It is known to provide ventilation ducts between the outer casing and the inner tube of the chimney, which ensure through the air flowing through that any moisture which forms is discharged through the air flowing through. In addition, at the CH 614990 A5 nor proposed to prevent passage of moisture into the mantle of the chimney characterized in that an aluminum foil is provided. Common to the chimneys, in the above Writings are described that it essentially depends on removing moisture from the chimney.

According to the generic state of the art ( DE 195 11 586 A1 ) Heat removal channels are provided within two shells of insulating bodies, wherein the shells are arranged to the actual insulation element within the fireplace along a radial separation plane composed within the chimney. The channels are in this case arranged substantially in the corner region of the chimney or of the constructed of two shells insulating body.

The DE 295 20 888 U1 describes a Schornsteindämmsystem in which the heat dissipation layer is not formed within, but outside of the insulating body.

In newer heating systems, especially in single-family homes, increasingly calorific value technologies are used, in which the heat of the exhaust gas is used for preheating in the heating system, so that the flue gas which is discharged through the chimney, has a relatively low temperature per se. In such fireplaces is no longer in the foreground that a certain moisture is avoided by dew point in the fireplace, but a problem is to provide through the insulation fire protection for emergency situations. For example, it can occur when depositing soot in the fireplace to a burn-out, in which instead of the usual temperatures of 50 ° C to 300 ° C maximum, a temperature of 1000 ° C may arise. In addition, the insulation must counteract especially during winter in frosty periods of excessive cooling of the fireplace and in particular the chimney head to ensure a sufficient train in the chimney. This is achieved by a sufficiently thick insulation is provided, which prevents the environment under extreme temperature stress (emergency) too hot or that the relatively low flue gas temperature at the chimney head (normal operation in winter) drops so much that a deduction of Flue gases could no longer be guaranteed. However, this requires a relatively thick-sized insulation, which in turn leads to a large cross-section of the chimney and a high consumption of space and insulation material. A relatively thick insulating layer would therefore be required, even in steel chimneys to pass the prescribed test for burnout resistance according to DIN with 1000 ° C hot test gas.

For this reason, it is an object of the present invention to provide a fireplace or corresponding insulating material, which ensures that excessive heating of surrounding parts is avoided in an emergency, as this also represents a fire hazard. Furthermore, the improvement of the insulating effect should be accompanied by a smaller footprint and lower insulation requirements.

This object is achieved by a chimney with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the realization that for a normal operation of a fireplace a much thinner insulation would be sufficient. Only for the emergency situation of a burn-out a corresponding precaution would have to be taken. This is achieved in accordance with the invention in a simple manner, that within the insulation, a so-called heat dissipation layer is provided which completely surrounds the chimney in essential parts and allows heat transfer in the axial direction and within the chimney from bottom to top. Such a heat transfer causes namely the two positive effects that on the one hand at a combustion of the chimney occurring in the lower part of the fireplace strong temperature load by the addition to the radial or horizontal insulation provided removal of heat in the vertical direction, ie upwards, manageable becomes. On the other hand, the proposed additional heat transport within the insulation in the direction of the chimney head causes it does not cool down too much in extremely cold weather, so as to provide the necessary train for the withdrawal of flue gases from the chimney. Such a heat dissipation layer can be realized by all materials having good heat conductivity. However, it has been found to be particularly effective to provide at least one channel or a plurality of recesses, in the form of tubes, gaps, slots and the like, through which a medium, preferably air, can flow to take over the heat dissipation or heat transfer. In order to achieve the greatest possible effect, it is preferred if the heat dissipation position, which should be arranged around the chimney for the entire height of the chimney, at least starting from flue gas introduction and as completely as possible, is formed as completely as possible by an annular gap. Only for stability reasons necessary spacers or supports should then interrupt the annular gap. In this case, it may then be advantageous to design the spacers or supports in such a way that they taper radially inwards, in order to provide an annular gap or a heat dissipation layer that is as continuous as possible in the circumferential direction despite the presence of spacers or supports.

In a particularly simple manner, such a fireplace according to the invention can be realized with insulating molded body elements. Namely, the Dämmkörperformelemente offer the possibility to realize the preferred for the heat transfer in the heat dissipation layer annular gaps, gaps, slots, tubes and the like. In a simple manner, the particular attention to obtain a full surface as possible surrounding heat dissipation position, can be achieved.

Thus, tubes can be integrally provided in Dämmkörper-form elements, while annular gaps can be provided by two-piece or two-shell design of Dämmkörperformelemente with formation of grooves or depressions in one or both shell bodies on the inner or outer sides. Since it is preferred to provide the Wärmeabfiihrungslage approximately centrally in the insulation, in particular offers a two-shell construction of Dämmkörper-form elements, wherein the annular gap is arranged in accordance with a centrally arranged coaxially to the flue pipe of the chimney separation surface. In order to prevent the annular gap from closing, appropriate spacers are then preferably provided here, which in particular can be designed to taper radially inward.

In order to enable a better transfer of the heat from the flue gas-carrying inner tube or arranged on this inner Dämmlage on the heat dissipation layer, means for improving the heat transfer can be provided. These will in particular formed by a layer having a high heat transfer coefficient, such as a metal layer of aluminum or copper. In this case, the metal layer can be formed by a preferably laminated foil or an inserted metal tube. In addition, layers of glass fleece, glass silk or a water glass spray coating are also conceivable as heat transfer agents. These have in common that they ensure a particularly good heat transfer, especially on the column, slots, tubes or other recesses flowing through medium. An aluminum foil with a thickness in the range of 17 to 60 μm has proven particularly useful.

In order to ensure a particularly simple production of Dämmkörper-form elements as well as the chimney itself, the Dämmkörper-form elements are preferably in the circumferential direction of several parts, in particular segmented, so that the segments in a simple manner between the flue gas leading inner tube and the outer casing will be attached can.

The Dämmkörper-form elements made of mineral wool, especially rock wool, preferably have a gross weight of 65 to 165 kg / m ³ , in particular 80 to 130 kg / m ³ and most preferably 110 to 120 kg / m ³ . In this case, it is advantageous to provide a higher bulk density, for example in the range of 110 to 150 kg / m ³ , on the inside, ie in the vicinity of the flue gas-carrying inner tube, while on the outside a lower bulk density, for example in the range of 80 to 110 kg / m ^{3 is} provided. In the axial direction of the fireplace, as is known, be composed of several shots.

Fig. 1

einen Querschnitt durch einen erfindungsgemäßen Stahlkamin;

Fig. 2

in Teilbild a) einen Querschnitt gemäß Figur 1 sowie in den Teilbildern b) bis e) Segmente von unterschiedlichen Dämmeinsätzen;

Fig. 3

einen Teilquerschnitt gemäß Figur 1(a) sowie einen Längsschnitt durch einen Kamin (b);

Fig. 4

einen Längsschnitt gemäß Figur 3 b); und in

Fig. 5

ein Diagramm, das den Temperatur-Zeitverlauf-Vergleich zwischen herkömmlichen Kaminen und dem erfindungsgemäßen Kamin bei einem Ausbrandversuch zeigt.

Further advantages, characteristics and features of the present invention will become apparent in the following detailed description of preferred embodiments with reference to the accompanying drawings. The drawings show purely schematically in

Fig. 1

a cross section through a steel chimney according to the invention;

Fig. 2

in part a) a cross-section according to FIG. 1 and in the panels b) to e) segments of different insulation inserts;

Fig. 3

a partial cross section according to FIG. 1 (a) and a longitudinal section through a chimney (b);

Fig. 4

a longitudinal section according to FIG. 3 b) ; and in

Fig. 5

a diagram showing the temperature-time course comparison between conventional fireplaces and the fireplace according to the invention in a burn-out.

FIG. 1 shows a cross section through a steel chimney according to the invention, which has an inner steel shell (inner tube) 1 and an outer tube 2 also made of steel. Between the inner tube 1 and the outer tube 2 insulating material 3, 4 is provided, which is formed in the illustrated embodiment of two composite ring bodies 3 and 4. The insulating material usually consists of mineral wool, in particular rock wool with a density of 65-165 kg / m ³ , in particular 80-130 kg / m ³ . Between the insulating elements 3 and 4, an air gap 7 is arranged, which stretches over the entire length of the fireplace. The air gap 7 is generated by spacing elements 5, which keep the inner ring body 3 and the outer ring body 4 at a distance and subdivide the air gap 7, at specific intervals in the outer ring body 4. Between the two ring bodies 3 and 4, an aluminum foil 6 is further arranged, which surrounds the inner ring body 3 completely over its entire surface. The aluminum foil 6 serves to deliver the heat absorbed by the inner annular body 3 as possible to the air flowing past in the annular gap 7.

The spacers 5 are formed as semicircular webs, so that they are in contact with the annular body 3 almost along a line. This ensures that the annular gap 7 is maximized in the circumferential direction. Of course, the spacers 5 may also assume other suitable cross-sectional shapes, in particular triangular, with the tips correspondingly pointing inwards.

The FIG. 2 shows in the partial image a) a cross section through a fireplace according to the invention, as he already in the FIG. 1 has been shown. However, the partial images b) to e) show a cross section through chimneys not according to the invention, wherein the insulating material arranged between the inner tube 1 and the outer tube 2 3 is also formed of one-piece segments. The tubes 7 for the air duct along the chimney can also have different cross-sectional shapes and be either on the inside (partial image d) or on the outside (partial image e) of the insulating body 3 or located in the insulating body (partial images b and c). The segmented design also facilitates the production of the insulating body or the partial insulation body 3, since then the areas that represent the annular gap 7, can be milled from the solid material in a simple manner, for example via appropriate wire milling.

FIG. 3 shows again in the diagrams a) and b) a fireplace according to the invention, as he already in the FIG. 1 is shown. The FIG. 3 However, it also makes clear that the annular gap extends over the entire length of the chimney (partial image b).

This is also in the FIG. 4 clearly, in which the drawing of the FIG. 3 b) can be seen in an enlarged view. It can be seen here that the chimney connection 8 can also be arranged laterally, wherein the annular gap 7 extends over the entire length and preferably has an opening at the lower end of the chimney. The arrows in FIG. 4 illustrate the flow of air flowing through the annular gap 7.

FIG. 5 shows how the temperature at the measuring points 1 and 2 of the FIG. 4 developed over time during a burnout attempt. By way of example, a burnout test was carried out in a stainless steel chimney with a 50 mm thick mineral insulating body and stomata (see drawing 1). The chimney was loaded with 1000 ° C for 50 min. The highest temperatures were measured at the chimney head without reaching critical values. In the present rear ventilation system, the temperatures on the outside of the chimney pot were well above the temperatures in the lower part of the chimney. This is in contrast to the temperature behavior of conventional (homogeneous) systems. In those, the highest temperatures in the inner tube as well as on the outer sheath are always measured above the entry point. As can be clearly seen, the temperature at the measuring point 2 in relation to the conventional chimney increases after a certain time, while it is lower at the measuring point 1 after a certain time than in a conventional chimney. This ensures that in a burnout more heavily loaded lower part of the chimney is cooled by a heat dissipation, while the temperature increase at the chimney head as a result of the heat transport remains in a non-critical range.

Claims (15)

1. A chimney, in particular a steel chimney with an inner tube (1) which leads smoke gas and an outer coating (2), which are both particularly made of steel and with an insulation between the inner tube (1) and the outer coating (2) which is made up of at least one insulation body form element (3, 4) out of mineral wool, in particular rock wool, with a heat discharge layer formed therein and extending at least from the smoke gas intake in axial direction to the chimney stack,
   characterized in that
   the heat discharge layer in the insulation extends over an essential part of the circumference of the chimney, and that the insulation body form element formed of several pieces and the at least one dividing face is arranged co-axially to the inner surface of the insulation body form element which surrounds the inner tube (1), so that the insulation body form element has a double-shell construction, whereas at the interface of the two shells (3, 4) radially open recesses (7) are provided at least at one shell (4), which form the head discharge layer, and which are limited by the other shell (3) which is adjacent to distance holders (5).
2. The chimney according to claim 1,
   characterized in that
   the heat discharge layer is formed by at least one channel (7) allowing passage of a medium, preferably air, therethrough, which is limited by the recesses extending along the interface of the insulation.
3. The chimney according to claim 1,
   characterized in that
   the distance holders become narrower from the inside to the outside, particularly taper off, so that the distance holders (5) preferably have line contact at their inner support.
4. The chimney according to one of the preceding claims,
   characterized in that
   the heat discharge layer is provided essentially radially in the centre of the insulation.
5. The chimney according to one of the preceding claims,
   characterized in that
   heat transmission means (6) for transmitting heat from the mineral wool to the heat discharge layer are provided at the heat discharge layer (7).
6. The chimney according to claim 5,
   characterized in that
   the heat transmission means (6) is formed by a layer with a high heat transmission coefficient which is at least partially provided at the inner face of the recesses, in particular a metal layer, preferably out of aluminium or copper.
7. The chimney according to claim 5 or 6,
   characterized in that
   the heat transmission means comprise a metal foil (6) which is preferably laminated, an inserted metal tube or -partial tube, a glass fleece, fibre glass or a water glass spray coating.
8. The chimney according to claim 7,
   characterized in that
   the metal foil has a thickness of 17 - 60 µm.
9. The chimney according to one of the preceding claims,
   characterized in that
   the insulation body form element is a multipiece element, in particular segmented, whereas the interfaces are in particular arranged partially radially, too, so that pitch circle segments are formed in case of preferably circular cross section.
10. The chimney according to one of the preceding claims,
    characterized in that
    the insulation material has a raw weight from 65 to 165 kg/m³, in particular 80 to 130 kg/m³, preferably 110 to 120 kg/m³, whereas the inner raw density is preferably higher, particularly 110 to 150 kg/m³, while the outer raw density is lower, preferably 80 to 110 kg/m³.
11. The chimney according to one of the preceding claims,
    characterized in that
    the heat discharge layer has a maximum amount of recesses in circumferential direction, preferably at least 80%, in particular 90 to 95%.
12. The chimney according to one of the preceding claims,
    characterized in that
    the cross section of the chimney and of the insulation body form element are round, rectangular, quadratic or polyangular.
13. The chimney according to claim 2,
    characterized in that
    the channel (7) has discharge outlets in the area of the chimney stack and entry openings for the air in the area of the chimney foot.
14. The chimney according to one of the preceding claims,
    characterized in that
    overflow nozzles are provided at the chimney stack for increasing the air flow.
15. The chimney according to one of the preceding claims,
    characterized in that
    the chimney has several stack sections.

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