EP0321667A1 - Heater - Google Patents

Abstract

The heater consists of a water-bearing housing (18), in which a combustion chamber (19) is arranged, from the end region of which a number of cross-sectionally slot-like heating gas flue pockets (2) are guided to a waste gas collecting chamber (20) with a smoke gas take- off, the pockets (2), which run parallel or approximately parallel, being arranged at a distance from one another. According to the invention, this heater is designed in combination with the following features: 1.1 The two neighbouring larger side walls (1) of each flue pocket (2) are provided with corrugated stampings (3) which are of identical shape and course, are directed from the side wall planes into the interior of the pockets and extend straight. 1.2 The corrugated stampings (3) are inclined in relation to the longitudinal edges (4) of the pockets (2) but in the respective side wall (1) arranged running opposite to the corrugated stampings (3) of the other side wall (1). 1.3 The corrugated stampings (3) make contact at the intersection points (5). 1.4 The corrugated stampings (3) end in front of the narrow side walls (6) and in front of the inflow and outflow openings (7, 8) of each pocket (2) with a separation which corresponds to at least one corrugation depth (T). 1.5 The number of corrugated stampings (3) in a side wall (1), which extend with their entire length (L) from the inflow opening to the outflow opening (8) of each pocket (2), is greater than the number of shorter corrugated stampings (3).

Description

The invention relates to a boiler according to the preamble of the main claim.

Such boilers with Heizgaszugtaschen in the water-carrying interior of the boiler housing are generally known and make the connection from the combustion chamber to the Heizgasabzug or to the Rauchgassemmelkammer with deduction. Such heating gas draft pockets are either arranged in a plurality, but separately, between the combustion chamber and the extraction area, or such pockets are combined to form a pocket block which is then arranged as a whole between the combustion chamber and the extraction area. For such hot gas draft pockets, it is known to emboss the side walls with ribs in order to intensify the heat transfer. To the extent that such ribbed embossments are provided, these are only a few embossments arranged at a relatively large distance from one another. This is probably because, in order not to let the flow resistance become too great, ie the pockets have to be accommodated in the boiler housing either in a correspondingly long and / or in a correspondingly large number in order to be able to guarantee a certain heat transfer performance in the boiler. As far as is known, the pockets of boilers equipped with them only insufficiently meet the complex requirements that must be taken into account. These requirements are simple manufacture and simple integration into the boiler, large heat exchange surface, based on the respective boiler, the smallest possible overall dimensions of the pockets, good swirling of the heating gases with justifiable flow resistance and pressure stability against the water pressure.

The invention is therefore based on the object to improve a boiler of the generic type with respect to the pockets in such a way that with a simple manufacture and easy integration of the pockets into the boiler housing and with the most extensive surface structure in the form of wave embossing and the associated increase in transmission area on the one hand the lowest possible flow resistance on the gas side should be achievable in the pocket to be designed with external pressure stability and, on the other hand, there should not be any embossing protrusions on the side surfaces that hinder the inflowing water, and the whole is connected with the proviso that with the possibility of swirling the entire gas volume flowing through, the greater part of the heating gases flowing through in the central plane of the pocket To find an exchange opportunity.

This object is achieved with a boiler of the type mentioned according to the invention by the combination of the features stated in the characterizing part of the main claim. Advantageous further developments result from the subclaims.

With this design of the boiler according to the invention with regard to its pockets, the demands made are met overall. Since the wave embossments are directed only into the interior of the pockets, the pockets which are to be arranged parallel to one another can be assigned to one another in relatively close proximity without there being any obstacles in the form of outstanding wave embossments in the upstream path of the water. As a result, there are no spaces inside the bag, based on the inflow and outflow cross-sections, into which the heating gas flowing through would have to expand. Except for the side wall area Chen and the areas immediately behind the inflow opening and in front of the outflow opening, the entire size of the side walls for the wave embossing is used, the relatively narrow, embossed edge areas on the one hand allow easy integration into the boiler housing and on the other hand easy closing or folding of the pocket along the narrow side edges. Since the wave embossing, which is only directed inwards, practically covers the entire side walls and intersects, there are a large number of mutual support points for the two side walls in the entire longitudinal center plane of the pocket. Since, furthermore, as mentioned, the embossments are only directed inwards, there is no expansion of the inflowing heating gases in the pocket in relation to the inflow cross section free of embossments, but rather a one-time compression on the inflow side to the available wave embossing cross sections, the heating gases essentially having their wave embossing continue to flow and only mix to a certain extent in the interface area of the longitudinal median plane of the pockets. Since the embossments are inclined with respect to the longitudinal edges of the pockets, a change to the other flow level of the pocket takes place to a certain extent only at the ends of the wave embossments, which do not extend with their total length from the inflow opening to the outflow opening. The associated resistance is reduced, however, by the fact that these alternating areas are free from wave embossing, which results in cross-sectional small, but not inclined, flow channels at the longitudinal edge areas in the pocket. In addition, the number of corrugations extending from the inflow to the outflow opening with its entire length is kept larger than the number of shorter corrugations. In this respect, the degree of inclination of the wave embossments depends only on whether the pockets are rather long than wide or rather wide than long in consideration of the space available for this in the water-carrying housing.

As for the statement that some of the claimed features are known, there is no need for individual documentary evidence, since these features belong to the general state of knowledge.

With so-called cross-flow heat exchangers, the pockets of the boiler according to the invention are not readily comparable, since such heat exchangers, as far as is known, are only formed from several stacked plates, while in the present case the gas-carrying pockets, even if they are combined as a pocket block, only the water-carrying ones Pass through the space in the boiler housing as separate heating gas flues.

As tests have shown, the special design of the boiler according to claim 4 leads to an extraordinarily favorable effect with regard to a reduction of the flow resistance with at least comparable heat transfer performance. Apparently, this is due to the fact that some of the heating gases find the direct path from the inflow side to the outflow side, but there are still turbulence areas when passing through the intersecting passages or wave embossments, and another part of the heating gases with the same turbulence effect also and inevitably change the direction of flow in the edge areas of the drawstring and also change the flow level. In order to be able to achieve a comparatively low flow resistance in bags of conventional type, it would be necessary to create the wave embossments much deeper. It is preferred that the heating gas draw pocket is designed such that the greater part of the wave embossings occupies two thirds and the smaller part a third the inflow or outflow opening of the pocket. The greater part of the wave embossing, which takes up the two thirds division, runs continuously from the inflow opening to the outflow opening of the pocket, while the other part of the wave embossing, which inevitably corresponds to the Relay of the longitudinal extent, practically forms a total of triangular surfaces with respect to the side walls of the heating gas draw pockets, so that the heating gas part flowing therein changes its direction in the respective edge region of the heating gas draw pocket and also has to change the "flow level".

Due to the achievable intensity of the heat exchange with a relatively low flow resistance, a reduction in the flow-through length of the hot gas train pocket can easily be considered, which of course also has advantageous effects on the external dimensions of the boiler in question, in which such hot gas train pockets are to be installed.

The boiler according to the invention is explained in more detail below with reference to the drawing of exemplary embodiments.

• Fig. 1 eine Seitenansicht einer Ausführungsform der Heiz­gaszugtasche;
• Fig. 2 einen Blick in die Heizgaszugtasche gemäß Fig. 1;
• Fig. 3 einen Schnitt durch die Heizgaszugtasche in Durch­strömrichtung;
• Fig. 4 eine Seitenansicht einer Tasche, die in bezug auf die Durchströmrichtung breiter als lang ist;
• Fig. 5 perspektivisch zwei Heizgaszugtaschen als Teil eines Taschenblockes;
• Fig. 6 perspektivisch den Anschluß zweier Heizgaszugta­schen an einen Brennkammerboden;
• Fig. 7 einen Blechzuschnitt vor der Zusammenfaltung zu einer Tasche und
• Fig. 8 A-C verschiedene Zuordnungs- bzw. Anordnungsmöglich­keiten der Taschen im Kesselgehäuse.

It shows schematically

• Fig. 1 is a side view of an embodiment of the Heizgaszugtasche;
• FIG. 2 shows a look into the heating gas draw pocket according to FIG. 1;
• 3 shows a section through the heating gas draw pocket in the flow direction;
• 4 is a side view of a pocket which is wider than long in relation to the flow direction;
• 5 perspective two hot gas draw pockets as part of a pocket block;
• Fig. 6 in perspective the connection of two Heizgaszugtaschen to a combustion chamber floor;
• Fig. 7 is a sheet metal blank before folding into a pocket and
• Fig. 8 AC different assignment or arrangement options of the pockets in the boiler housing.

As can be seen from FIGS. 1, 2, the hot gas train pocket consists of two side walls 1 with shape and course-identical wave embossments 3, which are mirrored together with wave support on the opposite and hot gas side at the intersection points 5 and gas and. Along their longitudinal edges 4 bent in the flow direction are connected to each other in a liquid-tight manner. As can be seen better from FIG. 3, the wave embossments 3 are embossed into the side walls 1 such that the wave embossments 3 end shortly before the edges of the inflow and outflow openings 7, 8 of the pocket 2. This simplifies the installation of such pockets in the bottom wall 14 provided with corresponding openings in a combustion chamber, not shown here, as shown in FIG. 6. The same naturally also applies to the outflow side, where the pockets 2 are integrated into a corresponding end wall 15 of the boiler housing or the bottom of a flue gas collection chamber. These edge regions not covered by wave embossments 3 are of course also advantageously provided if such pockets, as shown in FIG. 5, for example, are to be combined to form a pocket block.

As can be seen in particular from FIG. 2, the heating gas draw pocket 2 is advantageously designed in such a way that in the area of the longitudinal edges 4 there are no wave embossments 3 in both side edges, which results in non-inclined flow channels 16 running in the flow direction, in which the wave embossments 3 of the Open out parts II. This measure also reduces the flow resistance in the edge regions without, as has been shown, the aforementioned directional changes tion of the heating gases flowing there and the change of the "flow floors" is significantly impaired.

As has been shown, a range of 120 to 150 ° has proven to be the most favorable for the angle β. Larger values also cause turbulence, but this then subsides, while smaller values increase the flow resistance accordingly. In order to maintain the optimal range of 120 to 150 °, this requirement is taken into account by appropriate external dimensions of the pocket, because the condition must be met that part of the wave embossments 3 should extend continuously from the inflow to the outflow opening.

1, the larger part I of the corrugations 3, which are inclined with respect to the longitudinal flow center line 17, extends continuously from the inflow opening 7 to the outflow opening 8. The remaining part II of the corrugations 3, which is inclined in the same direction one side wall 1, which begins shortly after the inflow opening 7 and ends at the longitudinal edge 4 of the pocket, and part II of the other side wall 1, which begins at the longitudinal edge 4 and ends shortly before the outflow opening 8, have corresponding, decreasing towards the longitudinal edges 4 Lengths L, the lengths decreasing towards the respectively associated openings 7, 8 of the pockets 2. Seen in the inflow direction and in relation to the side wall 4 on the visible side, all channels formed by the wave embossments 3 of this side wall are acted upon, but not the channels extending in the left triangular region (additionally hatched). The same applies to the other side wall and only vice versa. The heating gases flowing in in area II cannot pass the hot gas flue pocket directly as in the other part I, but must change their direction in the edge area, as indicated by arrows, as well as change the flow level in order to be able to reach the outflow opening 8. Since the wave embossing 3 also on the Ge velvet surface evenly distributed corresponding intersection supports of the side walls 1 result in an extremely stable structure, so that relatively thin, for example stainless steel sheet can be used for the side walls 1. As can further be seen from FIG. 1, the dimensioning of parts I and II is advantageously provided such that, based on the overall width of the pocket, parts I of each plate occupy two thirds and part II a third of the pocket width.

7 shows a sheet metal blank that contains both side surfaces 1. As can be seen from this, the fields of the wave embossing 3 can, unless an appropriately large embossing tool is used, be produced with the same embossing tool that is only the size of one embossing field, since the other field has the same wave embossing profile. The two halves of the sheet metal blank 11, which represent the side walls 1, are folded or bent along the dash-dotted line, as a result of which the corrugated embossments 3 come to lie on the other half with an opposite slope. The edges 6 surrounding the embossing fields, which form the narrow side walls 6 in the finished and closed state of the pocket, are dimensioned such that their width corresponds approximately to a wave depth T. The middle, unembossed stripe has twice the width T and the two unembossed stripes, which form the inflow and outflow opening 7, 8 on the finished pocket, also have a width of about one wave depth.

For the sake of completeness, different arrangement options for the heating gas draw pockets 2 in the water-carrying housing 18 of different types of boilers are shown in FIG. 8, wherein the hot gas draw pockets 2 are grouped together separately or as a block, each extending from the bottom 14 of the combustion chamber 19 to the exhaust area 20.

Claims (6)

1. Boiler, consisting of a water-bearing housing in which a combustion chamber is arranged, from the end region of which a plurality of heating gas draft pockets, which are elongated in cross-section, are guided to an exhaust gas collection chamber with flue gas extraction, the parallel or approximately parallel pockets being spaced apart from one another, characterized by the combination of the partially known features: 1.1 the two adjacent larger side walls (1) of each drawstring pocket (2) are provided with straight and extending wave embossments (3), which are identical in shape and course, from the side wall levels (1 ′) into the interior of the pockets, 1.2 the corrugations (3) are inclined with respect to the longitudinal edges (4) of the pockets (2), but arranged in the opposite side wall (1) to the corrugations of the other side wall (1), 1.3 the wave embossings (3) touch at the crossing points (5), 1.4 the corrugations (3) end in front of the narrow side walls (6) and in front of the inflow and outflow opening (7, 8) of each pocket (2) with a distance that corresponds to at least one corrugation depth (T) and 1.5 the number of corrugations (3) in a side wall (1), which extends over its entire length (L) the inflow to the outflow opening (7, 8) of each pocket (2) extend is greater than the number of shorter corrugations (3 '). 2. Boiler according to claim 1,
characterized,
that the pocket (2) is formed from a sheet metal blank (11), which in each half contains the wave embossments (3) that are pronounced on one side, and that the two halves of the sheet metal blank (11) are folded against one another in parallel and the longitudinal edges of the sheet metal blank ( 11) are connected to one another in a gas-tight and liquid-tight manner with a longitudinal seam (12). 3. Boiler according to claim 1 or 2,
characterized,
that the pockets (2) are formed into a pocket block by means of connecting tabs (13) belonging to the sheet metal blank (11) and forming the shorter continuations of the large side walls (1) provided with the wave embossments (3). 4. Boiler according to one of claims 1 to 3,
characterized,
that part (1) of the corrugations (3), which are inclined with respect to the longitudinal flow center line (14 '), extends continuously from the inflow opening (7) to the outflow opening (8) of the pocket (2), while the rest, Part (II) inclined in the same direction of one side wall (I), which begins at the inflow opening (7) and ends at the longitudinal edge (4) of the pocket, and the other part (II) of the other side wall (1), which at the longitudinal edge (4) begins and opens out at the outflow opening (8), corresponding to the longitudinal edges (4), in the area of which these waves end, of decreasing lengths (L). 5. Boiler according to claim 4,
characterized,
that the larger part (I) of the corrugations (3) occupies two thirds and the smaller part (II) one third of the inflow or outflow opening (7, 8). 6. Boiler according to one of claims 1 to 5,
characterized,
that the angle of inclination (β) between the corrugations (3) of one side wall and the corrugations (3) of the other side wall (1) is up to 170 °, preferably 120 to 150 °.

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