DE2814155A1 - Heat exchanger for boiler - has stair cross-section flue gas tube enclosed by water jacket - Google Patents

Abstract

The heat exchanger is used for a boiler with an inner flue gas tube enclosed by a jacket forming an annular gap for water flow. The arrangement ensures efficient heat exchange. The inner tube (2) is provided with raised or depressed parts formed as longitudinal grooves to form a star-shaped cross-section. This profile cross section is in contact with the flue gases for heat transfer.

Description

Heat exchangers for incinerators

The invention relates to a heat exchanger for incineration plants with an inner pipe designed as an exhaust pipe, one the inner pipe at a distance surrounded outer pipe, which mivt the inner pipe a certain for water flow Forms an annular gap, a bottom that closes the annular gap at its ends and Lid and an inlet and outlet nozzle for the annular gap.

Various oil exchangers are already known with which the energy and loss of heating costs in incineration plants, e.g. B. central heating systems decreased shall be. What these heat exchangers have in common is that they are part of the exhaust gas or a flue gas pipe and a jacket for guidance and heating of water, which gets back into the heating circuit.

In a known heat exchanger of the type mentioned has the inner tube, which is usually arranged concentrically to the outer tube, has a smooth surface on. In order to achieve a satisfactory exchange of heat in this embodiment, the heat exchanger must be made relatively long.

In practice, however, the exhaust or flue gas lines often have incineration plants do not have any corresponding sections in which such a Heat exchanger could be installed as a part of the same. Or just can Shortened embodiments are used, which, however, are not yet fully enable satisfactory heat exchange and therefore with regard to their manufacturing and assembly costs are not particularly economical.

An attempt has also been made to exchange heat by installing further exhaust pipes of relatively small diameter in the to improve water-bearing jacket, these exhaust pipes end with the inner pipe are in connection and form an additional path for the exhaust gas disadvantageous The thing about this embodiment is that it has relatively large outer diameters leads, is also quite complex and accordingly expensive overall.

This is where the invention comes in. It is based on the task of one Further develop heat exchangers of the type mentioned at the beginning so that this is more compact Construction method, especially in terms of its overall height, but also in terms of its outer diameter, a satisfactory heat exchange is still permitted. At the same time, the heat exchanger should be relatively simple and clear and inexpensive to manufacture.

Surprisingly, a heat exchanger satisfies these diverse requirements in that, according to the invention, the inner tube is provided with elevations or depressions is.

The elevations or depressions can either be on the finished bent and welded inner tube can be attached in a subsequent embossing surface or can already be realized with the tabular starting material.

This simple measure sustains the heat exchange between Flue gas and heating water improved. On the one hand there is namely the effective surface of the inner tube enlarged, on the other hand a flow guidance that is more favorable for the heat transfer achieved.

The result can now be achieved with a heat exchanger according to the invention achieve the desired efficiencies, especially with a lower overall height. Became For example, otherwise a heat exchanger with a height of around 100 cm with a front-level one If an external diameter is required, a heat exchanger with a height of only 60 - 70 cm is sufficient.

The depressions are advantageously designed as longitudinal grooves.

Appropriately, the recesses taper towards the longitudinal axis of the Inner tube.

According to a further suggestion, the deepenings lend as a whole the inner tube has an approximately star-shaped cross section.

Further details are given below with reference to the drawing for a preferred embodiment described. These show: FIG. 1 a heat exchanger in the installed state in a schematic side view and FIG. 2 the object according to Figure 1 in an enlarged sectional view along the line 11-11.

According to FIG. 1, a heat exchanger 1 according to the invention has an inner tube 2 and an outer tube 3 surrounding the inner tube 2 at a distance. The inner tube 2 and the outer tube 3 are arranged concentrically to one another and form one Annular gap 4.

The annular gap 4 is at its ends with a base 5 or a cover 6 locked. Near the bottom 5 are an inlet connection 7 and near the cover 6, an outlet connection 8 for the annular gap 4 is attached to the outer tube 3.

As can be seen, the heat exchanger 1 forms a section of an exhaust gas or flue gas line 9 between an incinerator, namely a boiler 10 of a central heating system, and a chimney 11. In addition the inner pipe 2 is adapted as an exhaust pipe with one of the remaining exhaust pipe 9 Inner diameter formed.

The inner tube 2 has a water-bearing in the form of the annular gap 4 Mantle, in which water with extensive utilization of the sensible residual heat the exhaust gas is heated when it cools below 2000 C. From there the heated water is the heating circuit of the boiler 10 or the central heating system fed back.

For this purpose, the outlet port 8 is connected to the via a return line 12 The heating circuit of the boiler 10 is connected. In addition, the boiler owns 10 a return line 13, which via a valve 14 to the inlet connection 7 of the heat exchanger 1 is connected or connectable. This allows the heat exchanger 1, if necessary, switch on the heating circuit of the boiler 10. The boiler 10 leaves the heated water via a flow line 15.

According to the invention, the inner tube 2 is provided with elevations or depressions 16 provided, which increases the effective surface area and improves the flow conditions in the sense of a better heat transfer result.

As can be seen in particular in Figure 2, the wells 16 are as Läagsrillen formed which taper towards the longitudinal axis of the inner tube 2 and the inner tube 2 as a whole has an approximately star-shaped cross section to lend. Such an inner tube is relatively easy to manufacture and allows one good heat exchange between exhaust gas and water with a compact design, in particular relatively low overall height. The heat exchanger 1 shown is equally suitable for vertical, horizontal or any inclined installation.

Claims (4)

} see heat exchangers for incineration plants claims S heat exchangers for incineration plants with an inner pipe designed as an exhaust pipe, a das Inner tube at a distance surrounding the outer tube, which with the inner tube is a water guide certain annular gap forms, one closing the annular gap at its ends Base and cover as well as an inlet and outlet nozzle for the annular gap, thereby characterized in that the inner tube (2) is provided with elevations or depressions (16) is. 2. Heat exchanger according to claim 1, characterized in that the Depressions (16) are designed as longitudinal grooves. 3. Heat exchanger according to claims 1 and 2, characterized in that that the recesses (16) taper towards the longitudinal axis of the inner tube (2). 4. Heat exchanger according to claim 3, characterized in that the Depressions (16) overall of the inner tube (2) have an approximately star-shaped cross section to lend.