Background Art Known are heat exchange tube elements, consisting above all of circular section tubes, smooth on both sides, straight, U-shape bent, helical or spiral formed.

Also known are heat exchange tube elements consisting in tubes with extended outer surface or with an inner structure enhancing turbulence of the fluid stream. The elements of this kind are mostly straight.

From a Czech patent application PV 2010-94 a heat exchange tube element is known, composed of helical form sections and of stright sections.

From a Czech patent application PV 1166-93 a heat exchange element is known, consisting of a flattened aluminium tube comprising several longitudinal partitions. This tube is manufactured by pressing from two channel-type halves.

Most of said heat exchange elements must have a relatively thick wall, mostly merely for design reasons, e. g. for fastening of their ends in the tube plates, for bending, coiling, and consequently have a considerable weight and thereby they are expensive as to material and processing cost. The technical development trends in this field aim above all at a higher specific heat capacity per heat exchange area unit.

Disclosure of Invention The efficiency criteria mentioned above are substantially improved by the heat exchange tube element for liquid heat carrier fluids according to the invention, whose nature is in that a tube element consists in a smooth flattened elical formed tube, the longitudinal axis of the tube cross-section forming in relation to the helix axis an angle from 5 to 90° in positive and negative sense.

The inner tube space of the helilx coils is interconnected by a deaerating tube.

For improving the tube stiffness and enhancing the heat carrier fluid turbulence the flattened tube is fitted with pierced holes, which are perpendicular to the flat wall surface of the tube.

If an increase of the heat exchange area is required, the helix is made as a double or multipass member.

Brief Description of Drawings The drawings show schematically some examples of embodiment of the invention.

Fig. 1 shows a cross-sectional view of a heat exchange tube element, Fig. 2 shows an application of the tube elements according to the invention for building- up a horizontal residential heater, Fig. 3 demonstrates another modification of a residential heating body, Fig. 4 is an example of using such heat exchange tube element as a heat convection member of a panel-type hybridal heater and Fig. 5 is a view of a casing of the heater according to Fig. 4.

Examples of Invention Embodiment Example 1 A heat exchange tube element in Fig. 1 is formed by a flattened tube 1, having substantially an oblong straight section 2 with rounded short end sides and shaping a helix. The helix axis 3 is vertical. The longitudinal axis 4 of the oblong straight section 2 of tube 1 forms an angle of 30° with the helix axis 3.

The oblong straight section 2 of the tube 1 has dimensions 25 x 5 mm at a diameter of 50 mm of the helix central filament 5.

The single-pass helix pitch is 20 mm. Both the outer and the inner tube surfaces are smooth, the tube wall thickness is 0.2 mm. Water is used as the heat carrier fluid. The tube element is manufactured galvanotechnically of copper.

Example 2 Fig. 2 shows an application of the heat exchange tube elements for building-up a novel non-traditional residential heater. The heater consists of three heating elements 2,1.3, disposed coaxially in horizontal position.

Logitudinal axes 4 of oblong straight sections 2 of the tubes form an angle of 25° with the helix axis 3. The diameter of the inner helix central filament 5.1 is 55 mm, that of the intermediate helix 5.2 is 115 mm and that of the outer helix 5.3 is 175 mm. The flattened tube cross-section is 5 x 45 mm and is the same for all three elements. The helix pitch for all three elements is 40 mm. The inner spaces of the coils of each tube forming a helix are interconnected with deaerating pipes 7 having a diameter of 5 mm, and the heating elements are oriented in the heater so that all deaerating pipes 7 are at the highest point. All three heating elements 2,1.3 are fitted in the flattened tubes perpendicularly to the wall with pierced holes 6 with a diameter of about 10 mm at a pitch of about 60 mm. Water is used as heat carrier. Heated air flows through the heater along the arrow, i. e. in the direction of helix axis 3. The elements are manufactured in the same way as in Example 1 with a wall thickness of 0,3 mm. The heat exchange area of a heater having a length of 1 m is 2.6 sq. m. and the overall water volume in the heater is 5,9 litres.

Example 3 Fig. 3 shows schematically a residential heater, built up in the same manner as in Example 2. The difference consists in that the longitudinal axes 4 of oblong straight sections 2 of the tubes form with the helix axis 3 an angle of 80 ° both in the positive and in the negative sense. Heated air flows by own gravity

perpendicularly to the horizontal helix axis 3 as the arrow shows. The heater parameters and the production process are identical with Example 2.

Example 4 Figures 4 and 5 show the application of heat exchange tube elements as convection sections of a residential heater of a novel concept. It is in particular a panel-form hybridal box-type heater featuring a radiating part and a convection part, and is equipped with a bypass assembly for independent heat carrier fluid feeding to each part separately. The radiating part of heater 8 consists in a hollow panel 10 in which recesses 10.1 are formed. The heat carrier fluid inlet 11 and the bypass assembly 12 are situated on the side in the upper part of the heater 8.

The convection part is constituted by two double-pass helices 9 of flattened tubes. Each double-pass helix 9 is situated vertically in the chambres shaped by recesses 10.1 of the radiating hollow panel 10 in the box of the heater 8. The longer axis of the flattened tube cross-section forms an angle of 30 ° with the axis of the double-pass helix 9. The dimensions of the tube cross-section are 40 x 5 mm, the helix pitch is 40 mm, the diameter of the helices central filament is 60 mm. The heat exchange area of 1 current meter of the double-pass helix is sq. m, the heat carrier fluid volume is litres.

The double-pass helix 9 and the radiating part of the hybridal heater 8 are manufactured galvanotechnically of copper, obtained by galvanotechnical dissolution of sorted copper scrap.

Industrial Applicability The heat exchange tube element according to the invention is intended for an indirect heat exchange, above all in heating or cooling systems for the chemical, food processing, power or also automotive industries.

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