EP0017256A2 - Heat exchanger - Google Patents

Abstract

1. A heat exchanger which can be connected between the boiler outlet and the chimney inlet, having an annulus surrounding the flue gas pipe to preheat one or more separate media before they enter the boiler, characterized in that the heat exchanger comprises a series of annular chamber segments tandem joined by the building brick system, which exhibit, along with the central recess for the passage of the flue gas, the inlets and outlets (13, 17, 19, 21, 23, 26, 27, 29, 33, 37, 57) for the medium or media.

Description

The invention relates to a flue gas exhaust pipe for combustion plants according to the preamble of claim 1.

In the previously known central heating systems, both the hot service water and the water for the central heating network are heated in the same boiler. The consequence of this is that, for example, each removal of hot water from the hot water circuit must be supplemented by a corresponding amount of cold water from the water supply network. As this cold water usually has a temperature of about 8 ° C or less, it cools the left in the autoclave, at about 6o to 8 ₀ C setpoint temperature heated domestic water at its direct injection into the hot water circuit of the boiler. Switching on the heating is the normal consequence. Likewise, when the central heating is switched on after shutdown during the night or during a weekend or during operation with reduced temperature during the night hours the next morning, the completely or strongly cooled heating water circuit must be brought back to a higher flow temperature. For this purpose the boiler heating must be switched on for a long time. The flue gases generated during the operation of the boiler heating, which have temperatures of 2oo to 250 ° C, are led into the flue through a more or less long flue gas exhaust pipe.

To save heating energy, it has become known to bring together the water to be heated for heat exchange with the hot exhaust gas of the heating device, which has a solid, liquid or gaseous fuel fabric can be heated. So that the excess residual heat from the flue gas discharge pipe is dissipated to the fluid, so that it heats up. In order to reach the desired target temperature of the fluid, a lower heating output is necessary in the boiler.

An installation of the known additional heat exchanger is only possible where the existing dimensions between the boiler and the chimney correspond to the rigid gauge blocks of the heat exchanger. Such heat exchangers have so far only been able to establish themselves in large industrial companies and not in private heating systems.

It is therefore an object of the present invention to design a flue gas exhaust pipe of the type mentioned at the outset in such a way that simple installation is possible in new or existing systems, the flue gas exhaust pipe according to the invention being able to be adapted very simply to the structural conditions present.

This object is achieved by the characterizing features of claim 1.

Advantageous refinements result from the subclaims.

In the simplest case, the flue gas exhaust pipe according to the invention consists of two pipes arranged concentrically to one another, which are preferably held at a certain distance from one another by webs designed as flow baffles, the flue gases and being in the central interior of the inner pipe a fluid to be heated flows in the annular chamber formed by the two concentric tubes. This fluid is usually water. However, it can be provided for the _Z entralheizungskreislauf also known for this purpose to other liquid. Axially parallel tubes are arranged in the annular chamber, through which the second fluid to be heated flows. The ends of the pipes pass through sealing plates placed sealingly on the flue gas pipe and end in deflection chambers sealed by covers. In principle, the invention can also be applied to a circulating air heater, in which case cold air flows in the annular chamber formed between the inner tube and the outer tube as the fluid to be heated by the flue gases.

In a further embodiment of the invention, the flue gas pipe consists of a plurality of sub-members which can be connected in the axial direction and rigidly connected to one another, each of which has a closed annular chamber with fluid passage openings to the adjacent annular chambers. In these sections, the diameter of the inner tube is adapted to the standard diameters of the flue pipe socket on the boiler. In this embodiment of the invention, the flue gas exhaust pipe can be composed of any number of sub-members, similar to a radiator or sectional boiler, until the desired pipe length is reached.

In the simplest case, the partial links consist of hollow cast rings. When assembling these cast rings, the exhaust pipe for flue gases is formed from the central opening of the individual partial links arranged one behind the other. At the ring chamber of the last part of this In this way, the flue gas discharge pipe is connected to the cold water inlet, while the cold water connection to the boiler is connected to the first ring chamber.

When hot water is withdrawn at any point in the hot water network, the amount of hot water withdrawn must now be supplemented by a corresponding amount of cold water from the fresh water line. When this cold water is admixed, the target temperature for the heated process water in the boiler drops, so that a temperature sensor sends a corresponding signal to the heating control circuit, which in turn switches on the heating in the boiler. The flue gases generated during this heating period heat the cold water flowing through the ring chambers into the hot water boiler of the boiler on their way through the flue gas exhaust pipe and cool down during this heat removal. Depending on the length of the flue gas discharge pipe and the heat exchanger surface on the flue gas or cold water side, the incoming cold water is preheated, so that when it is mixed with the hot water present in the hot water boiler, the cooling of this hot water is significantly less than it would be without this preheating. This reduces the heating-up time to reach the target temperature and inevitably also the firing fabric consumption.

In order to achieve a more uniform temperature profile along the flue gas exhaust pipe, in a further embodiment of the invention the two flow paths of the fluids to be heated are not arranged one behind the other but alternately. This ensures that the fluid of the first system is passed through the first, third, fifth, seventh, etc. annular chamber, whereas the fluid of the second system flows through the second, fourth, sixth, etc. annular chamber. This alternating arrangement of the individual fluid paths results in a correspondingly more uniform preheating of the individual fluids. The two outlet lines for both fluids can emerge from the ring chamber closest to the boiler and be fed directly into the boiler. This facilitates the assembly of these lines.

In many cases, the consumption of the individual fluids is different, so that they should be processed in different quantities in the heat exchange device. To take this fact into account, it is proposed in an embodiment of the invention to adapt the widths of the annular chambers in the respective system to the respective fluid requirement, ie in other words that the annular chambers are designed to be narrower for the system with the lower fluid requirement. Such a different fluid requirement occurs especially in heating systems, which on the one hand are the water of the building or apartment heat the heating and on the other hand supply the hot domestic water. The hot water circulation is usually much lower than the heating water circulation. In this case, the fluid system for the domestic water will be provided with the narrower annular chambers. Instead of using a separate annular chamber for each flow path of the two heating systems, these two flow paths can be combined in one annular chamber. Such a heat exchanger has the advantage that both heat exchanger fluid systems draw heat from the same section of the flue gas pipe, so that one does not have to rely on an excessive length of the flue gas pipe. The basic element of such a heat exchanger or flue gas exhaust pipe, namely the central exhaust pipe with jacket pipe and the intermediate pipes arranged in the annular space, can be produced in standard lengths and can only be cut to specific installation dimensions on site. The boundary plates can be inserted or welded in and the covers placed on during the final assembly, so that the available section of the flue gas exhaust pipe can be optimally used.

Such a flue gas exhaust pipe can be developed so that the first heat exchanger fluid flows through the chambers formed by the cover and the restriction plate and the tubes arranged in the annular space and the second heat exchanger fluid system flows through the annular space outside the tubes arranged therein. The lid be designed such that they deflect the fluid flowing out of an intermediate tube and re-introduce it into the adjacent intermediate tube. Thus, the fluid flows through one pipe after the other and heats up accordingly due to the high mean residence time.

To improve the heat transfer efficiency between the flue gas and the fluids to be heated, devices that enlarge the heat exchange surface and / or flow swirling devices can be provided on the heat exchange surfaces both of the annular chamber through which the fluid flows and on the side of the inner tube through which the flue gas flows. For example, the devices which increase the heat exchange surface include Ribs, corrugated fins, webs, spikes and the like and as flow-swirling devices e.g. special surface roughness and structures, flow baffles, baffles and the like in question. Spirally arranged ribs in the annular chamber both increase the heat exchange area and swirl the fluid. Bars or ribs arranged on the flue gas side must also be arranged so that they do not hinder cleaning of the flue gas pipe.

Since the cold water from the fresh water supply network runs on immediately while hot water is being drawn, the temperature sensor usually only runs after After a certain mixing time between hot and cold water responds to the changed temperature in the hot water boiler, appropriate control measures are required. In order to ensure that the heating is switched on immediately when the cold water supply begins, the heating can either be switched on by starting to draw hot water from the hot water boiler. Another possibility is to arrange the temperature sensor in the hot water boiler in the area of the cold water inlet in such a way that it is washed up by the cold water flow and gives a control command to the heating without any delay. This ensures that hot flue gases are already available in the flue gas discharge pipe at the start of the cold water supply and preheat the incoming cold water.

As already mentioned above, two separate units of compound annular chambers can be provided, one for preheating the cold water flowing into the hot water boiler and the second for preheating the return of the heating system. For example, when heating up to the target temperature in the morning, all the heating water is already preheated after the burner is switched on before it reaches the boiler. Because in a central heating system the heated one contained in the central heating boiler Amount of water only makes up a small proportion of the flow water in the entire pipe and radiator system, the cooling of the flow water in these systems is correspondingly long and thus the heating-up time of the heating for reheating the flow water to the required target temperature is correspondingly long.

The flue gas exhaust pipe according to the invention shortens the heating-up time considerably due to the water already preheated in the annular chambers, since the annular chambers practically represent an additional capacity to the boiler itself. With the flue gas exhaust pipe according to the invention, no additional heating material is used, since only the in the flue gases escaping the atmosphere from the boiler are deprived of the thermal energy that has so far only escaped.

Due to the inventive simple possibility of adapting the flue gas exhaust pipe to existing dimensions, it can be easily installed in existing central heating systems or heating systems to be planned, since in any case a connection of the central heating boiler to the exhaust chimney is available or has to be made. The ring chambers are preferably made of cast material, but can also consist of steel or another suitable material. Items for cleaning the exhaust pipe can also be provided.

The cast rings can be connected directly to the boiler in the case of appropriately prepared boilers, so that the exhaust pipe and boiler form a unit. In this case, the preheated water is fed directly into the boiler without pipe fittings.

The smoke exhaust pipe according to the invention is independent of the fuel. It is equally suitable for solid, liquid and gaseous fuels. Likewise, the size of the boiler is irrelevant, so that the flue gas discharge pipe according to the invention is also suitable for the smallest family households as well as for industrial, district heating or other systems.

Depending on the length and cross-section of the flue gas discharge pipe, preheating the water to approx. 50 ° C and more can be considered quite realistic. In systems where there is no preparation for the attachment of the ring chambers to the boiler, i.e. where the connection of the ring elements with the boiler and the chimney is still required with conventional pipe sections, adapter rings are possible as start and end links, which ensure a gas-tight transition.

Embodiments of the present invention are shown in the drawing and will follow the described in more detail.

• Fig. 1 ein Rauchgasabzugsrohr für eine Feuerungsanlage, bei dem zwei verschiedene Kaltwasserkreisläufe angeschlossen sind
• Fig. 2 ein einzelnes Teilglied des Rauchgas-Abzugsrohres in perspektivischer Darstellung;
• Fig. 3 einen Vertikalschnitt durch das Teilglied gemäß Fig. 2;
• Fig. 4 eine Schnittansicht von oben durch eine Einheit von drei zusammengesetzten Teilgliedern;
• Fig. 5 einen Adapterring zur Ermöglichung einer Verbindung zwischen einem bisherigen Rauchgas-rohrstutzen und dem erfindungsgemäßen Rauchgas- Abzugsrohr;
• Fig. 6a,b schematische Ansichten des Rauchgas-Abzugsrohres an einem Heizungssystem in waagrechter und senkrechter Anordnung;
• Fig. 7 eine perspektivische Ansicht einer weiteren Ausführungsform des Rauchgas-Abzugsrohres;
• Fig. 8 einen Querschnitt längs der Linie III-III von Fig. 7 durch eine Anordnung mehrerer hintereinandergeschalteter Ringkammern mit unterschiedlicher Dicke;
• Fig. 9 einen Querschnitt durch eine andere Ausführungsform der Erfindung, wobei zwei Ringkammern unterschiedlicher Größe in einem Ring zusammengefaßt sind;
• Fig.10 eine perspektivische Ansicht einer weiteren Ausführungsform der Erfindung;
• _Fig.11 eine Stirnansicht der in Fig. 10 dargestellten Ausführungsform;
• Fig.12 einen Querschnitt einer weiteren Ausführungsform der Erfindung;
• Fig.13 eine perspektivische Ansicht des in Fig. 12 dargestellten Verschraubungsrohres;
• Fig. 14 a,b eine andere Ausführungsform der Verbindung der Ringkammern, wobei die Verbindungsschraube vom Fluid durchströmt wird;
• Fig. 15 einen schematischen Längsschnitt durch eine weitere Ausführungsform;
• Fig. 16 einen Querschnitt längs der Linie I-I in Fig.15;
• Fig.17 einen Querschnitt längs der Linie II-II in Fig.15; und
• Fig.18 einen Schnitt längs der Linie III-III in Fig.17
• Fig.19 einen Querschnitt durch die Ausführungsform des Wärmetauschers gemäß Fig.15 jedoch mit Halbrohren, und
• _Fig.2o einen weiteren Querschnitt gemäß Fig.19 mit U-Profilen.

Show it:

• Fig. 1 is a flue gas exhaust pipe for a furnace, in which two different cold water circuits are connected
• Figure 2 shows a single part of the flue gas exhaust pipe in a perspective view.
• 3 shows a vertical section through the partial link according to FIG. 2;
• Fig. 4 is a sectional view from above through a unit of three assembled sub-members;
• 5 shows an adapter ring to enable a connection between a previous flue gas pipe socket and the flue gas discharge pipe according to the invention;
• 6a, b are schematic views of the flue gas exhaust pipe on a heating system in a horizontal and vertical arrangement;
• 7 shows a perspective view of a further embodiment of the flue gas exhaust pipe;
• Fig. 8 shows a cross section along the line III-III of Fig. 7 by an arrangement of several ring chambers connected in series with different thicknesses;
• 9 shows a cross section through another embodiment of the invention, two ring chambers of different sizes being combined in one ring;
• 10 shows a perspective view of a further embodiment of the invention;
• _F ig.11 an end view of the embodiment shown in Fig. 10;
• 12 shows a cross section of a further embodiment of the invention;
• Fig. 13 is a perspective view of the screw tube shown in Fig. 12;
• Fig. 14 a, b another embodiment of the connection of the annular chambers, wherein the connecting screw is flowed through by the fluid;
• 15 shows a schematic longitudinal section through a further embodiment;
• 16 shows a cross section along the line II in FIG. 15;
• 17 shows a cross section along the line II-II in FIG. 15; and
• Fig. 18 shows a section along the line III-III in Fig. 17
• 19 shows a cross section through the embodiment of the heat exchanger according to FIG. 15, but with half tubes, and
• _F ig.2o a further cross section according to Fig. 19 with U-profiles.

In Fig. 1 with 1 the boiler, with 2 the burner, with 3 the flue gas discharge pipe, with 4 the chimney, with 5 the hot water boiler of the domestic water network, with 6 the central heating boiler, with 7 the heating water flow, with 8 the heating water return, with 9 the heating water inlet from the flue gas extraction pipe 3 into the central heating boiler 6, with 1o the fresh water inlet for the flue gas extraction pipe 3, with 11 the fresh water inlet into the hot water boiler 5, with 12 the hot water outlet from the heating boiler and with 13 the cleaning opening in the flue gas extraction pipe 3 designated.

FIG. 2 shows an enlarged partial representation of a single partial link, which is designed in the form of a cast ring 14. This cast ring consists essentially of a ring _. chamber 15 (Fig.3) in which the water to be heated flows. This water enters the annular chamber 15 via an inlet opening 16 on the end face of the cast ring and is deflected by a partition 17 (FIG. 3) such that it must first flow through the entire annular chamber 15 before it passes through the outlet opening 18 (FIG. 3) leaves the annular chamber 15 on the opposite end face of the cast ring 14.

Of course, several spiral gears can be provided in an annular chamber. The individual spiral ducts in each annular chamber 15 can have overflow openings, for example in the form of holes, slots, gaps and the like, in order to achieve a certain swirling effect. In order to be able to rigidly connect a plurality of cast rings 14, 14 ′ to one another, eyes 19 are provided on the outer circumference of the cast rings 14, 14 ′, through which tie rods 20 (FIG. 4) can be inserted. The flue gases flow from the heating furnace 1 into the chimney 4 through the central interior 21 of the cast ring 14.

As can be seen from FIGS. 3 and 4, a partition 17 running diagonally through the cross-section of the annular chamber in the area of the inlet opening 16 and the outlet opening 18 prevents the water to be heated entering the annular chamber 15 via the inlet opening 16 from escaping again immediately through the outlet opening 18 . Rather, the water must pass through the annular chamber in the circumferential direction, whereby it is heated by the flue gases flowing in direction A in the central interior 21. The cross flow between water and smoke gases ensures good heat transfer. Threads 22 can be provided in the inlet and outlet openings 16, 18, screwed into the external threaded sleeves 23 and the individual sub-members of the flue gas discharge pipe 3 rigidly, as in a sectional boiler can be connected. Special flow guiding devices and / or devices 26 which enlarge the heat exchange surface can be provided in the annular chambers 15.

FIG. 5 shows an adapter ring 24 to enable a connection between a previous flue gas pipe socket 25 on the boiler 1 and the flue gas discharge pipe 3 composed of several sub-members, with possibly a different inner pipe diameter. The flue gas pipe socket 25 is inserted into the adapter ring 24, while the last casting ring of the multi-unit flue gas discharge pipe 3 must be plugged onto the adapter ring 24.

6a and 6b show a further embodiment of the invention. A boiler 101 can be seen, on the rear side of which a flue gas discharge pipe 102 emerges and leads into a chimney 103. The annular chambers or cast rings 104 and 105 according to the invention form the flue gas discharge pipe 102 in one or more sections. The flue gas flows through the closely spaced cast rings. The dotted rings 104 belong to a first circuit and the white rings 105 to a second circuit. The cast rings or ring chambers 104 and 105 are arranged in alternating succession and are described in more detail below.

A mounting plate or a support 106 is also attached to the boiler 101, which surrounds or supports the flue gas discharge pipe 102 and can, for example, support the ring arrangement 104 and 105. The outlet lines 107 and 108 for the heating water HW and the process water BW are also held in the mounting plate 106 and lead the preheated water into the boiler 101.

The mounting plate 106 could also be mounted in a vertical arrangement directly on the outlet side of the exhaust pipe 102 on the boiler 101 if either the exhaust pipe 102 is guided on a longer horizontal path or the cast rings 104 and 105 around the bend of the exhaust pipe 102 to the boiler 101 are arranged. From this alternative it can already be seen that the rings 104, 105, in adaptation to the most varied structural conditions, offer universal application possibilities. The heated heating water HW exits the boiler 101 through the line 109 and is conducted therein to the individual radiators. The cooled heating water is led in a line 111 to the inlet opening of the first annular chamber 104a. The process water BW from the supply network is entered via line 112 into the inlet opening of the second ring 105a and conducted to the consumer points in line 110 coming from boiler 101.

FIG. 7 shows some rings of the ring chamber arrangement from FIG. 6, all of which have a central recess 114 for the flue gas exhaust pipe 102, and screw holes 115 for joining the individual rings together. The first ring 104a for the heating water system has an inlet opening 113 and a passage 116. Through this passage 116, the inlet 112 of the process water leads to the inlet opening of the narrower annular chamber 105a, which cannot be seen in the figure. The inside of the individual rings is best seen in Fig. 8.

In Fig. 8, the first annular chamber 104a is shown on the right side with the inlet opening 113, in which a pipe socket 113a is inserted for the purpose of connections. In alignment with the inlet opening 113, an outlet opening 117 is provided on the opposite side wall of the annular chamber 104a, at which a pipe socket 1.17a is formed. A deflector wall 118 is arranged in the interior of the annular chamber 104a and extends essentially in front of the inlet opening 113, so that the liquid entering through the inlet opening 113 is directed into the circular circulation of the ring and only after it has circulated on the rear side of the deflector wall 118 the outlet opening 117 can emerge. The passage 116 in the annular chamber 104a is sealed off from the interior of the annular chamber and leads to a pipe socket 119a of an inlet opening 119 of the second, narrower annular chamber 105a.

• Im Betrieb wird nun die durch die Einlaßöffnung 113 eintretende Flüssigkeit von der Abweiswand -118 in den Ring der Ringkammer 1o4a geleitet, durch den Auslaß 117 ausgegeben und durch den Rohrstutzen 117a an der Kammer 1o5a vorbeigeführt und in die Einlaßöffnung der dritten Kammer 1o4b eingegeben, in welcher der gleiche Strömungsvorgang abläuft. Die Flüssigkeit des zweiten Systems wird in die Durchführung 116 eingegeben und-gelangt durch die Einlaßöffnung 119 in die zweite Kammer 1o5a,in welcher sie von der Abweiswand in den Ringkreislauf abgelenkt wird. An der Rückseite der Abweiswand 12o tritt die Flüssigkeit durch die Auslaßöffnung 121 aus und gelangt über die Durchführung 121a in die vierte Kammer 1o5b. Die Durchführungen 116, 117a und 121a sind dabei derart dicht, daß sich die Flüssigkeiten der einzelnen Systeme nicht miteinander vermischen können.

Behind this inlet opening 119 there is also a deflecting wall 12o, which directs the incoming liquid into the circular ring. An outlet opening 121 is provided behind the deflecting wall 12o, on which a pipe socket 121a is formed. The pipe sockets 117a and 121a cast onto the outlet openings 117 and 121 have a length which corresponds in each case to the width of the subsequent chamber 1o5a and lo4b and thus bridge the adjacent chamber. These pipe lugs 117a and 121a are also attached to the pipe sockets 113b and 119b in the inlet openings of the annular chambers 1o4b and 1o5b in a liquid-tight manner:

• In operation, the liquid entering through the inlet opening 113 is directed from the deflecting wall -118 into the ring of the annular chamber 1o4a, discharged through the outlet 117 and passed through the pipe socket 117a past the chamber 1o5a and into the inlet opening of the third chamber 1o4b which is the same flow process. The liquid of the second system is introduced into the passage 116 and passes through the inlet opening 119 into the second chamber 10a, in which it is deflected by the deflecting wall into the ring circuit. At the rear of the deflecting wall 12o, the liquid exits through the outlet opening 121 and reaches the fourth chamber 1o5b via the passage 121a. The bushings 116, 117a and 121a are so tight that the liquids of the individual systems cannot mix with one another.

As already mentioned above, the individual ring groups can have a different thickness. At Central heating systems with simultaneous hot water preparation can be used, for example, for the process water, the narrower ring 1 ₀ 5 with a correspondingly lower flow rate and for the heating system, the wider ring lo4 with double or increased flow capacity. When the heating water is heated, the entire amount of water in the heating system, driven by the pump, flows several times to the radiators and back to the boiler during the cold season every time the burner starts. In this case, large-scale heat transfer from the exhaust gas is desirable. Larger throughputs are less common with process water because only a corresponding amount runs off from the network each time water is drawn. Experience has shown that larger quantities are only required when showering or filling the bathtub.

Another embodiment of the annular chambers shown in FIGS. 7 and 8 is shown in FIG. In this case, two adjacent annular chambers are combined in a common ring in which the corresponding chambers are formed. Such a ring 122 accordingly has a first inlet opening 123 which leads into a first ring chamber 124. Behind this inlet opening 123, the deflecting wall 128 is arranged, behind which the outlet opening 127 is located. On the same side as the inlet opening 123 there is a second inlet opening 126 which leads into an annular chamber 125 which is parallel to the annular chamber 124 but is narrower. Here, too, the deflecting wall 13o is arranged behind the inlet opening 126, behind which the outlet opening 129 located. After the individual chambers have to be penetrated from the inlet side to the outlet side by lines of the other chamber, a pipe socket 123a is provided between the first inlet opening 123 and the annular chamber 124, whereas a pipe 129a is provided from the outlet opening 129 of the annular chamber 125 to the outlet side of the ring 122 leads. With rings 122 arranged one behind the other, the outlet opening 127 and the inlet opening 123 of two adjacent rings for the first liquid system and the pipeline 129a of one ring are now aligned with the inlet opening 126 of the subsequent ring. To connect the individual transitions, as in FIG. 8, threaded sleeves 113a are used between the openings or pipes, which are used for the watertight connection of the chambers to one another. Otherwise, the mode of operation of the arrangement described in FIG. 9 is the same as that of FIG. 8.

The further embodiment shown in FIG. 10 represents a ring design which is favorable in terms of production costs. In this case, if no importance is attached to the different volumes, a single casting ring shape can be used for both systems. In this embodiment, the passage of the fluid from one chamber to the next but one takes place via a pipe which is guided outside on the intermediate ring. The annular chamber 134a for the first system has a nose-like projection 132, similar to that in FIG. 7, in which the inlet opening 133 is provided. Behind the inlet opening 133, as in the previous examples, there is a baffle, which the incoming liquid into the Annular chamber directs. At the rear of the deflector wall 338, indicated by dashed lines, there is the outlet opening 137, which merges into a pipeline 136. The length of the pipeline 136 is equal to the thickness of the ring 134a. The pipeline 136 is expediently arranged outside the ring diameter and is aligned with the inlet opening of the next-but-one ring 134b and is guided past the ring 135 lying therebetween.

For the second fluid system, the identically designed rings 135 are offset by a certain angle, for example 30 °, from the rings 134 of the first system, as can be seen from FIG. 11. Notches or beads (similar to tongue and groove) 14o are formed on the two end faces of the individual rings, by means of which the individual rings are secured against rotation when the ring set is screwed together. The screw connection through the bore 115 is expediently carried out for only one system, which thus holds these intermediate rings.

Of course, rings of different thicknesses could also be used in the example described in FIGS. 10 and 11. In such a case, it should be noted that the protruding pipe pieces 136 of one ring type have a length equal to the thickness of the other ring type and vice versa.

The advantage of the arrangement shown in FIGS. 10 and 11 can be seen above all in the fact that the flue gas discharge pipe can be easily adapted to the existing inlet and outlet lines. Manufacturing and warehousing are simplified.

Instead of a special design of the individual ring chambers, the flow openings and passages can also be formed in a special screw 141 connecting the individual rings to one another. Such a screw 141 is shown in FIG. 13, which essentially consists of a longer tube 142, which carries an external thread 144 at one end and has a slightly conical head 145 projecting beyond the tube diameter at the other end. In the head 145 there is the inlet opening 143, the inside of which is formed with an internal thread 146. The internal thread 146 mates with the external thread 144.

In the first third of the tube 142 there is an opening 147, which is arranged approximately opposite a second opening 149 in the cylindrical tube wall. Between the two openings the inclined wall 148 bweis- _A is attached. A mark 15o is attached to the end face of the head 145, through which the correct setting of the screw 141 can be seen in an annular chamber.

The relationship between the special screw 141 and the annular chambers is clear from FIG. 12. 12 shows a first annular chamber 154a, a second annular chamber 155a, a third annular chamber 154b, a fourth annular chamber 155b and part of a fifth annular chamber 154c. Line 151 denotes the inside of the inner cylinder surrounding the flue gas discharge pipe lo2. The special screw 141a, which is suitably sunk with its head 145 in a recess in the chamber 154a, is with its threaded end in the inside thread 146 of the next special screw 141b screwed into the chamber 154b. In the same way, the screw 141b is screwed with its thread into the thread of the screw 141c. The individual chambers 154 are thus pressed against one another and hold the intermediate chamber 155 firmly. The screw connection shown for the chambers 154 is expediently carried out on the other side of the exhaust pipe lo2 in the same way for the chambers 155, so that they hold the chambers 154 between them.

For screwing and tensioning, holes 158 or the like are provided on the end wall of the special screw 141, into which a tensioning tool can be inserted or inserted.

By correctly aligning the screws 141, their opening 147 comes to lie in the chamber 154a with respect to an inlet opening 153. Likewise, the opening 149 of the screw 141 lies opposite an outlet opening 157 in the chamber 154a. A liquid entering through the inlet 143 in the screw 141 is therefore directed through the baffle 148 in the screw through the recess 147 and the inlet opening 153 into the chamber 154a. After its cycle through the annular chamber, the liquid enters the tube of the screw 142 through the outlet opening 157 of the chamber and the recess 149 in the screw 141 and enters the inlet opening 143 of the next screw 141b. The pipe 142 is guided through a passage 152 past the intermediate chamber 155a. With such an arrangement, a modular system is created with which ring chambers of different sizes can be assembled with simple means. A Such an arrangement enables simple assembly since only a few screw connections are required.

In order to avoid sealing problems when assembling the ring chambers, the necessary screw connections can also be made accessible from the outside. In this case, as shown in Fig.14a, the inlet / outlet openings to the total width of the rings shortening that can be screwed or clamp a hexagonal flange with right-and left-hand thread _(F ig.14b) between the two mating rings.

But both inlet openings can also be produced offset by 18 ° _0, as indicated by broken lines indicated in Figure 11. This embodiment has the advantage that the screw connections of the individual rings are uniform. brace so that the additional screw connections 115 (Fig. 7) can also be omitted.

Another embodiment is shown in Fig. 15 In this embodiment, the annular chamber consists of a central part of variable length, on which end caps are placed on both sides. 15 shows a central flue gas pipe 21o, a jacket pipe 212 arranged coaxially therewith and axially parallel pipes 216 arranged in the annular space 214 between the central smoke pipe 21o and the jacket pipe 212. The pipes 216 lie close together and touch the outer surface of the central flue gas pipe. A small gap remains for fluid exchange or mixing between the inner surface of the jacket tube and the tubes. The tubes can be fixed with perforated bars.

The flue gas pipe 21o is provided with suitable flanges or connecting pieces in order to be able to be connected to the standardized flue gas pipe sections coming from the boiler or leading to the chimney. (These flanges are not shown.) The tubes in the annular space 214 are shorter than the central flue gas tube 21o and are passed through a front and rear boundary plate 218, 22o at their two ends. The implementation is liquid-tight, which can be done either by appropriate rubber seals, or by welding and soldering. The flue gas pipe 21o also passes through the boundary plates 218, 22o. Together with the casing pipe sections 212, a tight annular chamber is thus formed, which is only penetrated by the pipes 216. A fluid inlet 222 opens into the annular chamber, and a corresponding outlet 224 leads out of it again. Process water _B W can flow through this annular chamber, for example.

A domed cover 226, 228 is placed on the front and rear ends of the middle part. The edge of the cover can, as indicated by dash-dotted lines, be screwed pressure-tight with the limiting plates 218, 22o and, if appropriate, with a flange formed at the end of the casing tube 212. The central flue gas pipe penetrates both covers 226, 228 in a sealing manner. The bushing is preferably welded through the cover. This creates a front and a rear chamber 23o, 232, from which the fluid of the second system is supplied or removed. The fluid enters chamber 232 via inlet 234, flows through all pipes 216 in the same direction, collects in chamber 23o and exits outlet 236. In the embodiment shown the heating water HW circulates in this system.

In order to improve the heat transfer from the flue gas into the annular space, baffles 238 which narrow the free cross section can be fitted in the flue gas pipe 21o. These baffles ensure better turbulence and thus a higher heat transfer coefficient. Instead of the baffles, other measures can of course also be taken, for example hub-shaped displacement bodies can be installed, or baffles can also be provided which cause a spiral flow of the flue gas. In this case, however, it should be ensured that the inserts can be removed for cleaning. This is easily possible with flue pipes running in corners.

Since the pipes 216 have only a slight direct thermal contact with the inner exhaust pipe 21o and thus the heat given off to the fluid flowing in the pipes 216 is not too great, the pipes 216 can also be flowed through in succession according to a further embodiment of the invention. All that is required is a different design of the cover 226, 228. A view of such a cover is shown in Fig.17. As can be seen in connection with FIG. 18, the cover 228 is in any case made of solid material in the embodiment shown, into which certain cutouts 24o are made. The recesses 24o each have dimensions such that two of the tubes 216 each open in a recess 24o. (see Fig. 17). The webs between the recesses 24o lie tightly against the respective delimitation plates 218 and 22o and prevent the medium flowing in the pipes 216 from passing over.

Due to this modified cover, the fluid flowing in through the inlet 234 can no longer be distributed to all the pipes 216, but is sent into one of the pipes 216 via a somewhat smaller recess 242. After passing through a tube length, the fluid is deflected accordingly in a chamber 24o located in the other cover and flows back through the adjacent tube, whereupon a new deflection takes place and immediately until the last tube 216 is flowed through. If an odd number of tubes are arranged in the annular space 214, the inlet 234 and outlet 236 are each in a cover. If the number of pipes is even, the inlet and outlet can also be arranged in one and the same cover. In this case, however, a second, smaller recess similar to recess 242 must be provided in the cover in question.

The described embodiment has the particular advantage that the fluid flowing in the pipes 216 has a longer residence time in the heat exchanger, so that it can be heated to a higher temperature level.

The heat transfer to the pipes 216 can of course also be improved by other measures. For example, instead of the full pipes 216, it is possible to use only so-called half pipes 216a (FIG. 19), which are welded onto the central exhaust pipe 21o, so that a direct heat flow can take place from the central exhaust pipe to the fluid that is in the pipes 216 flows.

Any other open profile of any cross-section can of course be used instead of the half-tubes. It only has to be designed so that its edges can be welded to the outer surface of the ring tube, such as U-profiles 216b (Fig.2o).

The heat exchanger should also be equipped with a pressure relief valve. A flap can preferably be arranged between the heat exchanger and the chimney, which is intended to prevent recooling by cold air flowing in via the chimney.

Of course, the heat exchanger is insulated in a suitable manner in order to avoid heat losses as far as possible.

The flue gas discharge pipe according to the invention has proven itself particularly in summer operation, where generally only the process water system is in operation. The heating system is connected to a four-way mixer that is usually present in the system so that no heated water can flow to the radiators. The heated heating water only flows in a "short-circuited" circuit between the boiler and the four-way mixer. Since the ring chambers are installed between the four-way mixer and the boiler, there is constantly hot water in the rings belonging to the heating system even in summer operation, ie when the room heating is switched off. The adjacent rings of the domestic water system are therefore additionally heated by these rings of the heating system. If hot water is now drawn from any point in the process water system, a corresponding amount of cold water runs into the ring chambers of the process water system and is preheated as soon as it flows through the first ring chambers by the heat flowing through the ring chambers through which the heating water flows. There is therefore no significant cooling of the temperature in the boiler to the target temperature held water. Excessive start-up of the burner is avoided, which can result in energy savings of up to thirty percent throughout the year.

Claims (16)

1. flue gas exhaust pipe for combustion plants with a heat exchanger for recovering the thermal energy still contained in the flue gases, characterized in that the flue gas exhaust pipe (3,1o2, 21o) from one or more composite ring chamber segments (14; 104,105,134,135,154,155: 212,230, 232) with there are two or more separate flow paths for two or more different fluids to be heated, which are formed on the heat take-off side by means of the annular chamber (s), and a flue gas pipe (3.1 ₀ 2.21 ₀ ) delimited by the annular chamber (s). 2.Fume exhaust pipe according to claim 1, characterized in that the annular chamber segments (14,1o4,1o5,134,135,154,155) are each formed as closed components which can be strung together in the axial direction and are rigidly connectable, each with an inlet opening (16; 113,119,123,126,133,153) and an outlet opening (18,117,121,127,129,137,157) for the media to be heated, the inlet opening and outlet opening of adjacent annular chamber segments coming to lie fluid-tight on one another. 3. flue gas exhaust pipe according to claim 2, characterized in that the annular chamber segments (1 ₀ 4.1 ₀ 5,124,125,134,135,154,155) have a closed with respect to the chamber interior passage (117a, 121a, 123a, 129a, 136,152), the outlet opening (117,121,127,129,137,157) of the Connect the preceding ring chamber segment (1 ₀ 4,124, 134,154) with the inlet opening (113,119,123,126, 133,153) of the following ring chamber segment (1 ₀ 5,125,135,155). 4. flue gas exhaust pipe according to claim 1, characterized in that the annular chamber segment (212,23 ₀ , 232) consists of a middle part of variable length and a front and rear, the middle part delimiting, from the flue gas pipe (21o) penetrated cover (226,228), that in the annular space (214) of the middle part (212) to the flue gas pipe (21o) Axially parallel tubes (216) are arranged which pass through a front or rear, the annular space (214) delimiting boundary plate (218,220) and that between the boundary plates (218,220) and the front or rear cover (226,228) a front and rear Chamber (230,232) is formed, into which the tubes (216) each open, the one fluid to be heated circulating through the tubes (216) and the other fluid to be heated in the annular space (214) outside the tubes. 5. flue gas exhaust pipe according to claim 4, characterized in that the tubes (216) in the annular space (214) are arranged close to each other and their diameter is slightly smaller than the inside width of the annular space (214) that the supply and discharge one of the fluids to be heated is arranged in the cover (226, 228) and the supply and discharge of the other fluid to be heated are arranged in the central part (212), and that the covers (226, 228) are curved in the manner of a dished bottom and with the boundary plates (218, 220) are screwed to the circumference. 6. flue gas exhaust pipe according to claim 4 or 5, characterized in that the tubes (216) in the annular space (214) have an open cross section and their edges are welded to the outer surface of the flue gas pipe (210). 7. flue gas discharge pipe according to any one of claims 4-6, characterized in that the cover (226,228) have internal recesses (240, 242), into each of which two adjacent pipes (216) open that webs between the recesses (240,242) are provided, which largely prevent fluid exchange between two adjacent tubes (216), and that the front and rear covers (226, 228) are rotated relative to one another by the angle of a tube (216), so that the first heat exchanger fluid all of the tubes (216). flowed through in succession. 8. flue gas exhaust pipe according to one or more of claims 1-7, characterized in that in the annular chamber and / or the flue gas pipe flow control devices (118, 120, 128, 130, 138, 148) and swirling devices (27, 238) and the heat exchange surface enlarging devices (26) are provided. 9. flue gas discharge pipe according to claim 3, characterized in that in the fluid inlet and outlet openings (16,18; 113,119,123,126, 133,153,117,121,127,129,137,157) threads (22) are provided, via which the annular chambers (15) by screwing in external threaded sleeves (23) individual parts can be connected to each other. 1 ₀ . Flue gas discharge pipe according to claim 3, characterized in that the _R ingkammern (1 ₀ 4,124,134,154,1 ₀ 5,125,135,155) of the two flow paths having a different width. 11. smoke exhaust pipe according to claim 1 ₀ , characterized in that two annular chambers (124,125) are combined in a ring unit (122) which has an inlet opening (123,126) and an outlet opening (127,129) for each flow path. 12. Flue gas discharge pipe according to one of claims 1-3, characterized by a nose-like projection (132, 135) on the outer surface of the annular chamber (134), in which the inlet opening (133), the deflecting wall (138) and the outlet opening (137) are provided are, the inlet and outlet opening are in communication with the interior of the chamber and the outlet opening (137) is followed by a pipe extension (136) extending beyond the ring width. 13. Flue gas discharge pipe according to claim 12, characterized in that the length of the tube extension (136 is equal to the thickness of the adjacent annular chamber (135a) and flush with the inlet opening (133) of the next but one annular chamber (134b). 14. Flue gas exhaust pipe according to claim 12 or 13, characterized in that on one The end face of an annular chamber (134, 135) has notches (140) and on the other end face, beads which cooperate with the notches (14o) are provided to prevent rotation. 15. Flue gas discharge pipe according to one of claims 1 to 3, characterized by a through a passage (152) of a chamber (155a) through hollow screw (141) which mechanically arranged on both sides of this chamber (155a) arranged annular chambers (154a, 154b) connects to one another and enables a flow between these two annular chambers, the screw essentially consisting of a long tube (142) in which a first recess (147) aligned with the inlet opening (153) in the annular chamber (154a) and a second recess (149) aligned with the outlet opening (157) of the annular chamber (154a), and that the deflecting wall (148) is arranged between these two recesses (147, 149). 16. Flue gas exhaust pipe according to claim 15, characterized in that. the hollow screw (141) has an external thread (144) at one end and an internal thread (146) which matches the external thread (144) and which is accommodated in a projecting screw head (145) at the other end.

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