Heat-exchanger comprising a plurality of helically wound pipe elements

The invention relates to a heat exchanger with a plurality of stacked tube spirals, which are connected at their ends with risers, each forming an inlet or an outlet for one of the heat exchange to be subjected to media, while the other of these media in contact with the outer walls of the tube spirals flows through a space which is bounded on the outside by a jacket surrounding the pipe spirals.

There are known heat exchangers of the type described above, in which each tube spiral forms a substantially circular disc and all these discs are arranged in planes which are perpendicular to an axis passing through the centers of the discs axis. The one riser is arranged on the circumference of the disk stack. The other riser extends along the axis, ie in the middle of the discs. The risers are usually connected by brazing or welding with the pipe spirals. Due to the centrally located riser pipes can lead to a leak leading to breakage of a pipe spiral they are only replaced if all the other pipe coils are removed on one or the other side of the damaged pipe spiral before. In such a case, therefore, numerous brazing or welding joints have to be cut open and after performing the repair, new such joints must be restored. Breakage of a pipe spiral may be caused, for example, by corrosion or mechanical vibrations or by a combination of these or other adverse operating conditions. This heat exchanger also has the disadvantage that, even if it were possible, at least temporarily up to an optimal time for the repair to take into account the loss of possibly only a small number of tubular coils caused reduction in the capacity of the heat exchanger, this measure is not applicable because the risers are common to all pipe spirals.

In other known heat exchangers of the initially mentioned type, although the risers to which the pipe coils are connected, are arranged radially outside of these spirals, but it is through the center of the pipe spirals other, the heat exchanger belonging, risers out and / or at the periphery of the pipe spirals arranged riser pipes distributed over more than half of the circumference of the pipe spirals, so that there are also considerable difficulties in replacing a pipe spiral.

The object of the invention is now to provide a heat exchanger in which the above-mentioned disadvantages and limitations are eliminated. The heat exchanger according to the invention of the type mentioned above is characterized in that all the riser pipes within the shell of the heat exchanger, but outside of the pipe spirals, are arranged and all risers, which extend over the full height of the stack, are arranged in the same half of the circumference of the pipe spirals ,

The most important of this arrangement related technical advantages is that the failure of a single pipe spiral whose connections can be cut off easily with both risers, since the two risers are easily accessible due to their arrangement outside of the disk stack. Even more important, however, is the fact that after loosening the pipe spiral, it can be pulled out of the stack without having to loosen adjacent, non-failed pipe spirals. As a result, not only the repair costs are greatly reduced, but also the time required to perform the repair is greatly shortened, so that the costs caused by the shutdown of the heat exchanger costs are correspondingly lower.

You can also divide the tube coils of the heat exchanger in two or more groups, which are connected with two risers. Then you need in an error that does not affect all groups, not to take the whole heat exchanger out of service, but it is sufficient in this case, only turn off the defective group, which can be done with the help of suitable shut-off devices attached to the corresponding risers are. Thus, the heat exchanger does not need to be completely shut down, but is reduced in case of damage, only the capacity of the heat exchanger.

Hereinafter, an embodiment of the invention will be described in more detail with reference to the drawing, which shows diagrammatically, partly in section, a heat exchanger according to the invention with divided into three groups pipe spirals.

The heat exchanger shown in the drawing has a lower part -1-, by means of a connecting flange -2- carries a substantially cylindrical shell -3-. In the selected embodiment, the shell encloses only a single stack of disks and the shell has a lower flange -4- and an upper flange -5- for the connection of the heat exchanger with a conduit which is traversed by a medium which in the heat exchanger the Heat exchange is subjected, that is, absorb heat or give off heat. Therefore, this medium flows through the heat exchanger substantially vertically and touches the outer walls of the individual pipe coils -6- of the stack. Each of these pipe spirals has substantially the shape of a flat circular disk. Several of these discs are stacked to form a stack. Each pipe spiral consists of a pipe, usually of copper or steel, connected at its two ends by brazing, welding or in any other suitable manner to one of two risers -7 and 8-.

As is apparent from the drawing, however, only those arranged in the upper third of the stack

Pipe spirals connected to risers -7 and 8-. The heat exchanger has two more pairs - 3 -

No. 309482 of riser pipes, designated -9, 10 and 11, 12, respectively, adjoining the risers -7 and 8 and connected to the pipe spirals forming the middle and lower thirds of the stack, respectively. The stack is therefore divided into three pipe spiral groups -A, B and C-.

It is now assumed that during operation of the heat exchanger shown in the drawing one of its tube spirals fails, so that the medium exits from this tube spiral and mixes with the other medium. The invention then allows the following measures

First, the heat exchanger is emptied, whereupon the screws are removed from the flange -2-, so that the jacket -3- can be lifted. Now all pipe spirals are freely accessible, not only for checking all their connections with the riser pipes, but also for selectively loosening the damaged pipe spiral or pipe spirals. The connections between the pipe spirals and the riser pipes are the most critical locations, especially when the heat exchanger is exposed to vibration. Since all the risers are arranged on the circumference of the stack, it is not only possible to solve one or more of the pipe coils more comfortable than in the known heat exchangers with centrally located risers, but you can also move a pipe spiral after disconnecting from their risers horizontally and from Remove the stack without this movement is hindered by a centrally arranged riser. As has been stated above and can be readily understood, in the known heat exchangers with centrally located riser pipes, all pipe spirals must be removed on one side of the damaged pipe spiral before it can be taken out. In order to avoid additional work, a second condition must be met, namely that all risers extending over the whole height of the stack are arranged in the same half of the circumference of the stack. The drawing clearly shows that this condition can be met if the stack is divided into several parts, in which case a correspondingly larger number of risers is required. It will also be appreciated that a repaired or replaced pipe coil can be conveniently connected, and that the total time required for repair is much shorter than in conventional heat exchangers with pipe spirals.

In certain cases, for example when the heat exchanger forms part of a plant for carrying out a continuous chemical process, even the repair time, greatly shortened by the invention, can lead to serious disadvantages. These are inventively avoided in that the stack is divided into several, in the illustrated embodiment in three parts, which are each provided with two risers. These risers are connected by shut-off valves, not shown, with pipes arranged outside the shell, so that the heat exchanger can also work when one or more of the stack parts are separated. It is understood that for such operation, the heat exchanger must have an overcapacity when all parts of the heat exchanger are in operation. Calculations have shown that the extra work involved in this overcapacity is more than compensated for by the extra security, especially against complete closure. In the practical application of the invention, the heat exchanger can also be dimensioned in the usual way. If a faulty part of the heat exchanger is then switched off, the reduction of the capacity due to a higher load is compensated for until an optimum time for carrying out the repair work.

From the foregoing description it can be seen that the arrangement of both ends of the pipe spirals on the circumference leads to important advantages in terms of construction and operation. As in the heat exchangers of the present type, the longitudinal axis of the shell is arranged generally vertically, was spoken here in the description of risers and is stated in the claims that the pipe spirals are stacked. However, the invention is not limited by these illustrative terms. You can also choose the number of arranged in a common coat stack arbitrarily.