EP1439354B1 - Heat exchanger - Google Patents

Abstract

The heat exchanger has a finned tube (2) in a casing (1). The tube has primary (3) and secondary (4) sectors aligned with horizontal (10) and vertical (12) center axes respectively. There is a gas burner (13) in the primary sector and a channel (15) in the secondary sector, formed by a central displacement body (18) and the casing.

Description

The invention relates to a heat exchanger arrangement according to the features in the preamble of patent claim 1.

Such a heat exchanger arrangement is counted by the "Installation and Operating Manual Energy Mini Nox" Cooperative Inkoopvereniging "Coopra-Rotterdam" NV, Haringvliet 72, NL-3011 TG Rotterdam, 10 / 98-1, p. 6 to the prior art. It serves to provide hot water. This heat exchanger assembly has a pipe with individual transverse ribs incorporated in a housing in a helical configuration in a housing, which is connected at its upper end to a cold water supply and at the lower end to a consumer for hot water. The coiled tube has an identical diameter over its entire height. In the tube, a cylindrical displacement body is incorporated in the lower height range, which is followed by a gas burner upwards. Due to the external shape of the displacement body and the inner surface of the housing, a channel with an annular cross-section is formed in the lower height region, to which a condensate drainage in the form of a trough is connected. The outlet nozzles of the gas burner are directed radially and are spaced from the upper height range of the tube. Another heat exchanger assembly according to the features in the preamble of claim 1 is known from EP-A2-1 255 086 known.

The housing receiving the pipe, the displacement body and the gas burner is integrated with further control and regulating elements in a box, which is fastened in particular in the household to a wall.

In view of the fact that the box is usually relatively high hung, the access to the gas burner for maintenance and repair work is relatively complicated. It must not only open the panel of the box, but usually the entire box can be removed from the wall to get from the top of the gas burner. The associated effort is thus high.

Furthermore, it should be noted to the known design that the gas pressure ratios in the heat exchanger with respect to the gas burner receiving primary portion in relation to the displacement body receiving secondary portion can not be defined properly. A clean separation of the hot gas utilization in the primary section of the condensation in the secondary section is not possible. As a result, the gas burner is loaded unevenly. Ultimately, the known arrangement leads to deteriorated heat exchange conditions.

The invention is - starting from the prior art - the object of a heat exchanger assembly, in particular for domestic hot water, to provide, which is easier to maintain and in which the heat exchange conditions are significantly improved.

This object is achieved with the features stated in the characterizing part of patent claim 1.

An essential point of the invention is that now the coiled tube is divided into two fluidly interconnected lengths, of which a primary section has a horizontal center axis and the gas burner surrounds at a distance, while the displacement body enclosing the secondary portion of the tube has a vertical center axis.

This arrangement of the lengths of the pipe, the condition is created that the gas burner is readily accessible from the front, so that after removal of at least parts of the box paneling the fitter has no problems performing repairs and maintenance on the gas burner. A removal of the box from the wall is no longer necessary.

Another advantage of the invention is seen in the fact that is subjected to the uniform separation of the hot gas utilization in the primary section with horizontal center axis and the condensation in the secondary section with a vertical center axis of the gas burner, a uniform load, which significantly improves the heat exchange conditions.

Furthermore, this arrangement ensures that in the primary section of the heat exchanger, the combustion gases are cooled down so much that a special insulation of the housing can be omitted. As a result, the effort is further reduced.

In the secondary section with a vertical central axis, the combustion gases are then cooled so far that at reflux temperatures below the dew point of the combustion gas condensate is formed, which is derived at the lower end of the secondary section.

In the primary section, the pipe may be unaffected. The secondary section of the tube is however ribbed. Here, in the embodiment according to the invention, two segment-like peripheral regions of each rib pointing in the direction of the condensate discharge are bent along the direction of flow of the combustion gas at an angle of about 90 ° to the flow direction of the combustion gas in a V-shaped manner out of the rib plane. As a result, a gap is formed between these peripheral regions. With this Design of the ribs, a targeted tight flow around the tube is achieved by the combustion gases, the resulting higher flow velocity entrained by the resulting droplets in the condensation and transferred to the condensate drainage. The heat transfer performance is further improved.

An advantageous development of the invention provides according to claim 2, that two bent in the flow direction of the combustion gas next to the pipe diametrically opposite segment-like peripheral regions of each rib of the lying in the channel secondary portion of the pipe along the flow direction of the combustion gas parallel fold lines 90 ° out of the rib plane and between two in the circumferential direction of the ribs successive folded peripheral regions are provided column. In this way, the flow guidance of the combustion gases in the annular channel on the circumferential side of the combustion body is further improved, that is, together with the V-shaped bent peripheral regions care is taken that the combustion gases are brought close to the pipe zoom to the heat exchange conditions even further improve.

According to the features in claim 3 but also of the penetrated by the gas burner primary portion of the tube with parallel spaced apart, be equipped in the initial state round ribs. In this case, two circumferential regions of each rib which are situated in the direction of flow of the combustion gas are also bent in a V-shape about 90 ° out of the plane of the ribs, so that a gap is formed between the peripheral regions. This form also means again a close pre-introduction of the combustion gases to the tube in the primary section with regard to an intensive heating of the water in the pipe.

Based on the formation of the ribs in the secondary section, it is possible according to the features of claim 4, that lying in the flow direction of the combustion gas next to the pipe in the penetrated by the gas burner primary segment segmental perimeter of each rib along the flow direction of the combustion gas parallel fold lines 90 ° to the rib plane folded and between two circumferentially of the rib successive peripheral areas column are provided. As a result, the heat exchange conditions are also further improved.

The life of the heat exchanger is then increased if according to claim 5, the tube and the ribs made of a resistant to the combustion gas and its condensate material. Depending on the application, this material may be aluminum or stainless steel in particular. But other materials, even in combination, are conceivable in individual cases.

Figur 1

im schematischen vertikalen Längsschnitt einen Wärmeaustauscher für einen Warmwasserbereiter;

Figur 2

in vergrößertem Maßstab den Ausschnitt II der Figur 1;

Figur 3

ebenfalls in vergrößertem Maßstab den Ausschnitt III der Figur 1;

Figur 4

in vergrößertem Maßstab eine Seitenansicht auf einen Längenabschnitt eines wendelförmigen Rohrs gemäß dem Pfeil IV der Figur 1 und

Figur 5

eine Draufsicht auf die Darstellung der Figur 4 gemäß dem Pfeil V.

The invention is explained in more detail with reference to an embodiment illustrated in the drawings. Show it:

FIG. 1

in a schematic vertical longitudinal section, a heat exchanger for a water heater;

FIG. 2

on an enlarged scale the section II of the FIG. 1 ;

FIG. 3

also on an enlarged scale the section III of FIG. 1 ;

FIG. 4

on an enlarged scale, a side view of a length of a helical pipe according to the arrow IV of FIG. 1 and

FIG. 5

a plan view of the representation of FIG. 4 according to the arrow V.

With 1 is in the FIG. 1 a housing of a heat exchanger WAT referred to, in addition to not shown control and regulating units is integrated into a box, also not shown, which can be hung as a total water heater in a household on a wall.

In the housing 1, a coiled tube 2 is incorporated, which is composed of two longitudinal sections 3, 4. The one end 5 of the tube 2 is connected to a cold water supply 6 illustrated only schematically and the other end 7 to a consumer 8, also illustrated only schematically, for hot water.

The primary section 3 of the tube 2 lying in the upper height region 9 of the housing 1 has a horizontal center axis 10 and the secondary section 4 located in the lower height region 11 has a vertical central axis 12.

In the primary section 3, a gas burner 13 is arranged with radially directed outlet nozzles 14. The gas supply is not illustrated in detail.

The secondary portion 4 of the tube 2 is located in a channel 15 with an annular cross-section, which is formed on the one hand by the inner surface 16 of the housing 1 and on the other hand by the outer surface 17 of a circumferentially closed displacement body 18. The channel 15 is connected in a manner not shown to a condensate drain 19.

The tube 2 is provided both in the primary section 3 and in the secondary section 4 in the initial state round, spaced-apart ribs 20.

As the FIGS. 2, 4 and 5 can be seen in detail, are in the ribs 20 in the secondary part 4 in the direction of the condensate discharge 19 facing segmental peripheral regions 21 along the flow direction STR of the combustion gas obliquely extending crease lines 22 to each other V-shaped bent by about 90 ° from the rib plane RE. In this way, a gap 23 is formed between these peripheral regions 21. Furthermore, the show FIGS. 2, 4 and 5 in that also two in the flow direction STR of the combustion gas next to the pipe 2 diametrically opposite segment-like peripheral regions 24 of each rib 2 of the secondary section 4 along the flow direction STR of the combustion gas parallel bend lines 25 are bent by 90 ° from the rib plane RE. As a result, between two circumferentially UR of the rib 20 successive folded peripheral portions 21, 24 column 26 is formed.

The formation of the bent peripheral portions 21, 24 causes the combustion gases in the channel 15 are brought close to the tube 2, so that the heat transfer conditions are significantly improved.

Also in the ribs 20 in the primary section 3 are two in the flow direction STR l of the combustion gas each forward circumferential portions 27 of each rib 20 along the flow direction STR l of the combustion gas oblique bend lines 28 to each other V-shaped bent by about 90 ° from the rib plane RE ( FIGS. 1 and 3 and in corresponding approximation the FIGS. 4 and 5 ). Between the peripheral regions 27, a gap 19 is formed. Furthermore, the show FIGS. 1 and 3 and in corresponding approximation the FIGS. 4 and 5 in that, in the flow direction STR 1 of the combustion gas, segment-like peripheral regions 30 of each rib 20 lying parallel to the pipe 2 in the primary section 3 extend parallel to the flow direction STR 1 of the combustion gas Crease lines 31 are bent by 90 ° to the rib plane RE. As a result, and by the peripheral regions 27 bent in the shape of a V, gaps 32 are formed between two circumferentially successive circumferential regions 27, 30.

The combustion gases passing from the outlet nozzles 14 of the gas burner 13 are therefore directed exactly radially outwards and are brought close to the tube 2, so that here too the heat exchange conditions are significantly improved. Subsequently, the gases pass according to the arrows 32 in the channel 15 and are here also, as described above, performed closely around the tube 2 in the secondary section.

REFERENCE NUMBERS

1 -

casing

2 -

pipe

3 -

Primary section v. 2

4 -

Secondary section v. 2

5 -

End of v. 2

6 -

Cold water supply

7 -

End of v. 2

8th -

consumer

9 -

upper altitude range v. 1

10 -

Central axis v. 3

11 -

lower altitude range v. 1

12 -

Central axis v. 4

13 -

gas burner

14 -

Outlet nozzle v. 13

15 -

channel

16 -

inner surface v. 1

17 -

outer surface v. 1

18 -

displacer

19 -

condensate drainage

20 -

ribs

21 -

Peripheral areas v. 20

22 -

Kink lines v. 21

23 -

Column between 21

24 -

Peripheral areas v. 20

25 -

Kink lines v. 24

26 -

Column between 21 and 24

27 -

Peripheral areas v. 20

28 -

Kink lines v. 27

29 -

Gap between 27

30 -

Peripheral areas v. 20

31 -

Kink lines v. 30

32 -

arrows

RE -

ribs level

STR -

flow direction

UR -

Circumferential direction v. 20

WAT -

heat exchangers

Claims (5)

1. Heat exchanger arrangement comprising a housing, a burner, a displacement body and a heat exchanger, which has an at least partially finned tube (2) incorporated in a helical configuration into the housing (1), which tube can be connected by one end (5) to a cold water supply (6) and, by the other end (7), to a consumer (8) for hot water, wherein the gas burner (13) provided with radially directed outlet nozzles (14) is arranged in a primary portion (3), adjacent to the cold water supply (6), of the tube (2) and a secondary portion (4), adjacent to the consumer (8) and having a vertical centre axis (12), of the tube (2) is arranged in a channel (15) having a circular cross section and a lower condensate outlet (19), the channel being formed by the inner surface (16) of the housing (1) and the outer surface (17) of the inner displacement body (18), characterised in that the primary portion (3) of the tube (2) surrounding the gas burner (13) at a spacing has a horizontal centre axis (10) and the secondary portion (4) of the tube (2) passing through the channel (15) is provided with round fins (20) oriented parallel to one another, wherein two segment-like peripheral regions (21) of each fin (20) pointing in the direction of the condensate outlet (19), along bend lines (22) running obliquely with respect to the flow direction (STR) of the combustion gas, are slanted in a V-shape with respect to one another through about 90° from the fin plane (RE) and a gap (23) is formed between the peripheral regions (21).
2. Heat exchanger arrangement according to claim 1, characterised in that two segment-like peripheral regions (24), diametrically opposing one another next to the tube (2) in the flow direction (STR) of the combustion gas, of each fin (20) of the secondary portion (4) located in the channel (15), along bend lines (25) extending parallel to the flow direction (STR) of the combustion gas, are slanted through 90° from the fin plane (RE) and gaps (26) are provided between two slanted peripheral regions (21, 24) following one another in the peripheral direction (UR) of the fin (20).
3. Heat exchanger arrangement according to claim 1 or 2, characterised in that the primary portion (3) of the tube (2) passed through by the gas burner (13) is equipped with round fins (20) arranged at a parallel spacing with respect to one another, in which two peripheral regions (27) of each fin (20) located to the front in the flow direction (STR I) of the combustion gas, along bend lines (28) running obliquely with respect to the flow direction (STR I) of the combustion gas, are slanted with respect to one another in a V-shape through about 90° from the fin plane (RE) and a gap (29) is configured between the peripheral regions (27).
4. Heat exchanger arrangement according to any one of claims 1 to 3, characterised in that segment-like peripheral regions (30) of each fin (20) located in the flow direction (STR I) of the combustion gas next to the tube (2) in the primary portion (3) passed through by the gas burner (13), along bend lines (31) extending parallel to the flow direction (STR I) of the combustion gas, are slanted through 90° with respect to the fin plane (RE) and gaps (32) are provided between two peripheral regions (27, 30) following one another in the peripheral direction (UR) of the fin (20).
5. Heat exchanger arrangement according to any one of claims 1 to 4, characterised in that the tube (2) and the fins (20) consist of a material which is resistant to the combustion gas and its condensate.

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