DK152625B - HEAT EXCHANGING - Google Patents

Description

The invention relates to a heat exchanger of the kind specified in the preamble of claim 1.

Such heat exchangers are most effective in aligning them so that both media run in a clean countercurrent to each other. In small-tube heat exchangers, where the tubes are coiled in a spiral for reasons of space, it is known to produce a pure countercurrent by allowing a dense lead sheet plate to follow in the spiral, thereby forcing the medium outside the spiral tube to follow the tube. its entire length.

There are many applications for heat exchangers of the present type, e.g. radiator exchangers, ventilation exchangers, domestic water heaters for district heating or cooling plants and field surface heating exchangers. Each application has its flow ratio between the two media, depending on the desired temperature differences and the available pressure drops. Therefore, for a given pipe dimension, the flow area in the ducts outside the pipes must be varied if the structure is to be adapted to the varied requirements.

In prior art embodiments of such heat exchangers, the principle has been used that the pipe spirals are placed in a stack with a suitable distance for each application area between the different layers of the stack. Alternatively, the rise of the coil can be used as a variable for adapting the structure to a certain application. In both cases, there are manufacturing complications that contribute to the cost of heat exchangers. In addition, this means that most heat exchangers get an unnecessarily large building volume, which leads to increased costs and installation problems.

The present invention aims to provide a heat exchanger of the kind in which the said drawbacks are avoided and this is achieved according to the invention in that the heat exchanger is designed as defined in the characterizing part of claim 1.

This provides that in one and the same construction, instead of increasing the flow area in the ducts outside the pipes, when the flow there is greater than normal, a certain division between the coils can be maintained and also can maintain the rise of the coils, but can shorten the flow path in that the current is "short-circuited" locally to a certain extent by overflow between two adjacent turns of the coil. This short circuit can, by practical manufacture, take place locally in a number of points which may be very large. The efficiency of the countercurrent heat exchanger is not significantly affected.

The invention is explained in more detail with reference to the drawing, in which: FIG. 1 shows a vertical section through an embodiment of the heat exchanger according to the invention, and FIG. 2 The inner part of the heat exchanger as seen from above and partly in section.

In the illustrated embodiment, the heat exchanger has a container composed of two end pieces 1 and 2 and a cylindrical sheath 3. In one end piece 2 opens a central pipe 4, while two manifolds 5 and 6 pass through the other end piece 1. Furthermore, a tube 7 exits the sheath. Between the manifolds, a plurality of tubing coils 8 run, which in the illustrated embodiment are guided three and a half turns around the center axis of the container. The inner ends of the tubes are connected to the manifold 5, while the outer ends are connected to the manifold 6. The pipe spirals and the manifolds form a flow path for one medium, while the container and tubes 4 and 7 form a flow path for the other medium.

In the pipe spirals, a guide plate 9 is wound which extends between the end pieces 1 and 2 and forms a plurality of helical channels 10 between the pipes 8 and between these and the end pieces. The second medium is forced through these channels and thereby brought into close contact with the tubes. As stated above, the heat exchanger becomes most effective when the two media flow counterclockwise. In the present case, therefore, one medium must flow clockwise in FIG. 2 and the other counterclockwise e.g. as shown by the direction of arrows 11 and 12 in Fig. 2.

For excessive flow rates in the channels 10, it has been found that the pressure drop through the exchanger becomes abnormally large, which is why a shortened flow path for the medium would be desirable. Such a shortened flow path is obtained according to the invention by successively shorting many small angles of flow through overflow to the next channel 10 in the coil.

Constructively, this overflow, as in the embodiment shown, can be effected by means of holes 13 in the guide plate for each channel 10. By varying the dimensions of the holes and / or the hole pitch, the exchanger can be adapted to varying requirements to reduce the flow resistance of the flowing in the channels 10. medium, without having to change the spiral distance or pitch. The alteration of the hole divide is a very simple measure from a manufacturing point of view, so the major disadvantages of the previous designs can be avoided in this way. It is also possible to make the conductor plates interchangeable and select a conductor plate for each application with a hole division and hole dimensions that provide the best heat exchange at a certain current flow. The choice of such a guide plate results in increased flexibility in the use of the exchanger, so the parts used in the exchanger can be standardized, with the only part to be performed in a plurality of models being the guide plate.

The embodiment described above is an example of how the invention can be realized. Changes in · this embodiment can be made e.g. in that the tube spirals, instead of circular, are wound in any oval shape. It is also possible to replace the hollow partition of the tinplate with one or more interruptions in the tinplate, which then take the form of a number of sections, the interruptions serving as overflow sites between two adjacent channels 10, while the "capacity" of the overflow site is determined by the interruption size.

Claims (5)

A heat exchanger for heat exchange between two media in which one medium is passed through a coil of spaced tube coils (8), while the other medium is passed through a plurality of externally extending helical channels (10) formed along the tubes (10) between the tubes and a helical guide plate (9) which is wound into and around the tubes of the individual pipe spirals, characterized in that the guide plate (9) has at least one overflow opening (13) between two channels (10) located on opposite sides of the plate. Heat exchanger according to claim 1, characterized in that the overflow openings consist of holes (13) in the guide plate (9). Heat exchanger according to claim 1, characterized in that the overflow opening is formed by a break in the coil formed by the guide plate. Heat exchanger according to claim 2, characterized in that the guide plate is interchangeably mounted in the pipe spirals. Heat exchanger according to claim 4, characterized in that a series of guide plate plates have mutually different number of holes and hole dimensions.