DE3320265A1 - Tube-in-tube heat exchanger - Google Patents

Abstract

The tube-in-tube heat exchangers known to date, which are built from round tubes placed centrally, or else non-centrally, in one another, and form straight or spiral tube bundles, give rise in production to a number of design as well as construction problems. It is the object of the invention to develop a compact tube-in-tube heat exchanger which is very effective in terms of heating engineering and can be used for a plurality of functions (cooler, condenser, evaporator, preheater). This is achieved when a smooth tube or a tube with an annular, spiral corrugation is mounted in the interior of the enclosing tube, this enclosing tube having an oval or elliptical cross-section. Owing to this shape of the outer tube, the inner tube is seated firmly by means of punctiform, linear, or else areal contact of the two tubes. Vibrations are reduced to a high degree. The performance of tube-in-tube heat exchangers designed in this way is also enormously increased, owing to the turbulence of the medium, which is particularly promoted by the design.

Description

The invention relates to a double-tube heat exchanger} particular in district heating, refrigeration _s chemical engineering and high-pressure technology as a radiator, condenser or evaporator pre-heater can be used.

There are known double tube heat exchangers made of round tubes, which are inserted centrally or not centrally into one another and form straight or spiral tube bundles. The inner tube can be special on its surface be shaped »e.g. ribbed to intensify the heat exchange.

The construction of such heat exchangers usually creates design and execution problems, among others with attachment of spacers between pipes, vibration and insulation issues.

The development is based on the task of a thermal engineering very effective and compact double tube heat exchanger to be developed that also functions as a cooler (, condenser » Evaporator or preheater can be used.

The object is achieved according to the invention in that a smooth tube or a tube of annular, spiral or helical corrugation is inserted inside the outer casing tube with an oval or elliptical cross section, the ratio of the smaller to the longer axis varies from 0.2 to ₀ 9.

3320 ^ 65

Both tubes are arranged in point, ruler, or surface contact with one another.

The advantages achieved with the invention are that, thanks to the oval shape of the tube with a larger radius ₉ , it is possible to achieve a smaller minimum bending radius that the tube is stuck, especially in the version with a spiral tube bundle, by point, ruler , but surface contact with the outer tube. Thanks to this arrangement, the vibrations are substantially eliminated. Furthermore, no spacers are needed between the tubes. The wave-shaped design of the inner tube brings additional turbulence in the medium and, in the case of two phase media, separation of the phases.

In the case of condensation, for example. A very good separation of the gas and liquid media is achieved, as well as elimination the formation of a liquid film on the outer wall of the inner tube. The condensate mainly flows in the sub-channel (3)> There is mainly steam in the upper duct (4.).

With a wavy inner tube, very intense evaporation occurs. The additional promoted by corrugated surfaces Turbulence facilitates the separation of the liquid droplets from steam, also improves heat exchange.

As already indicated, the oval or elliptical outer tube can be arranged in a spiral with a small radius be, whereby the heat exchangers can be made very compact.

In Fig. 1 is a fragment of the double-tube heat exchanger as an example namely in the interior of the outer jacket tube (1) shown by an oval cross-section, in which a tube (2) helical corrugation is used. The condensate mainly flows in the sub-channel (3)> Steam, on the other hand, is mostly in the upper canal (4.).

Claims (1)

Dr-Ing Heinrich Hampel AIfons Maatζ Mussumer Ringstrasse 9 ^{In the hallway} " ^ 290 Bocholt 4290 Bocholt Double tube heat exchanger Claims 1 / iDouble tube heat exchangers in district heating, refrigeration V / chemiechen process engineering or high pressure technology can be used as a cooler, condenser, evaporator or preheater characterized, that inside the outer jacket tube of an oval or elliptical cross-section. ■ a smooth tube or. a tube of ring-s spiral, "or helical corrugation 9 is used with the ratio, varies the smaller to the longer axis vo ~ N O., O 2 to ₈ 9, 2 / double tube heat exchanger according to claim 1 characterized, that the maximum diameter of the inner tube is insignificantly larger, equal to or insignificantly smaller than The inner minimum diameter of the jacket pipe is 5 3 / double tube heat exchanger according to claims 1 and 2 characterized by ^ that the jacket tube and the inner tube are either designed as straight or in spirals or else 33202 ⁷ 65 are arranged in meandering pipe systems; 4 / double tube heat exchanger according to claims 1, 2 and 3, characterized in that that the size of the minimum bending radius of the oval or elliptical jacket pipe is equal to the minimum allowable bending radius of the inner pipe; 5 / double tube heat exchanger according to claims 1, 2, 3 and 4 · » characterized, that inside the outer of an oval or elliptical cross-section casing pipe two or more Tubes with a round cross-section, smooth or with annular or helical corrugation are used.