DE3532009A1 - PIPE HEAT EXCHANGER - Google Patents

Description

The invention relates to an apparatus for intensive exchange of heat between two hermetically separated media, whereby a large surface is achieved in that a large number of thin-walled tubes tightly sealed together be connected without the use of tube sheets.

The currently known tubular heat exchangers all have one another common that the pipes at both ends in Perforated plates are used, connecting the pipes with the bottom and the sealing by rolling, soldering, Can be glued or welded into the perforated base.

This version has a number of disadvantages:
- Elaborate production of perforated floors
- Perforated floors usually require very large wall thicknesses to avoid warping during processing and operation, which makes the apparatus very heavy.
- Hole spacing and thus the narrowest pipe spacing are limited by the machinability when punching (drilling, punching) and the stability of the floor
- Crevice corrosion can usually not be avoided, especially with inexpensive designs.

The invention has for its object the lightest possible and inexpensive tube heat exchanger made of corrosion-resistant To create material in which the two participated in the heat exchange Media are hermetically sealed, and in which at least the media-contacting surfaces of one side are designed so smooth that neither the so feared crevice corrosion can occur in heavy dirt still carried in the medium can adhere to cleaning angles.  

These requirements must be met especially with heat recovery systems the chemical industry z. B. the dryer exhaust air must be satisfied.

This object is achieved in that the individual tubes at their two ends to an equilateral Hexagon widened, its wrench size straight is slightly larger than the pipe diameter. Let it through put these pipes together in parallel so that they face each other A honeycomb pattern is created, with the individual tubes touch only on the front sides along straight lines, while the cylindrical tube middle parts a small distance from each other hold and so all-round rinsing of the pipe wall allow outside through one medium while through the pipes the other medium flows inside. The pipe ends are like this executed that the hexagonal cross section over several millimeters Pipe depth is observed, so that the pipes on this Hexagon prisms lie flat against each other.

The seal between the two media is now very light produce, e.g. B. by gluing, soldering or in particular welding the pipe ends along the hexagonal contact surfaces.

Electrical welding can be carried out practically without any additional wire and very thin-walled tubes can be used.

The tubes can be used for heat exchange between two gas flows in the middle part an elliptical one instead of a cylindrical one Have cross-section, so that for the flowing through the tube Medium a relative to the scope and thus to the exchange area very favorable so-called hydraulic diameter results and a very good one for the medium flowing around the pipes Small flow resistance based on the specific volume flow.  

The following important advantages can be achieved with the present invention:
- Construction of a hermetically sealed tube bundle heat exchanger only from tubes without pre-perforated end plates.
- Use of very thin-walled pipes
- Very light apparatus for use in ventilation systems.
- Very rigid structure of a bundle
- Simple welding technique when welding the pipes.
- Extremely smooth surfaces can be achieved on the end face and the inside of the pipe.
thereby:

• - no crevice corrosion
  - low risk of contamination
  - Easy cleaning even during operation by water or steam jet

- With an elliptical cross-section, you have on the outside of the pipe:

• - low flow resistance
  - Low vortex flow and thus low susceptibility to pollution

- The hexagonal cross-section of the tubes allows the tubes to be rotated by 60 ° each time they are assembled. I.e. in the case of an elliptical tube middle part, the external flow channels can be directed as desired.
- With a round pipe center cross-section, large inner tube volumes can be verified with small outer tube volumes of a tube bundle; this is important when exchanging heat between very different media.

Claims (4)

1.) Pipe bundle heat exchange apparatus with two hermetically separated media spaces characterized by the fact that the individual pipes are expanded at both ends over a depth of several millimeters to form a hexagonal cross-sectional profile , the outer width of which is slightly larger than the outer pipe diameter, and which without Perforated end plates are assembled into a tube bundle with honeycomb end faces and are tightly connected to one another by welding, soldering or gluing the hexagonal contact surfaces or lines. 2.) Pipe bundle heat exchanger apparatus according to claim 1, characterized in that the individual pipes in the middle section (approx. 90% the tube length between the hexagon ends to an elliptical Cross section are pressed. 3.) Pipe bundle heat exchanger apparatus according to claim 1. and 2. thereby characterized in that the longitudinal axis of the ellipse in a 60 ° grid rotated can be arranged arbitrarily, so that of quasi-rectilinear up to constantly diverted flow any flow control behavior can be manufactured. 4.) Pipe bundle heat exchanger apparatus according to claim 1 characterized in that the outer border of the end faces by Welding of pre-cut sheets to rectangular, hexagonal or round apparatus faces.