DE29602990U1 - Water heater - Google Patents

Description

*· »· ··
· · * * · *
, . ··· * ,-' : ::·*. t ·
. . · ·" *
Joh . Jan""ISi
GmbH U. Co. GM 1436

The invention relates to a water heater according to the preamble of claim 1.

In such water heaters, the heat exchanger is usually located in the combustion chamber, with the tubes of the heat exchanger only being arranged in one plane. However, this has the disadvantage that the heat of the combustion gases and the heat radiation from the burner can only be partially utilized, resulting in a correspondingly low level of efficiency.

The aim of the invention is to avoid these disadvantages and to propose a water heater of the type mentioned at the beginning, which is characterized by a higher efficiency.

According to the invention, this is achieved in a water heater of the type mentioned at the outset by the characterizing features of claim 1.

The proposed measures ensure that the combustion gases always flow past a hollow body through which the heat exchange medium flows, or its wall.

At the same time, the parts of the heat exchanger surrounding the burner are exposed to its radiant heat.

The features of claim 2 result in the advantage of particularly good utilization of the heat of the exhaust gases. The combustion gases that flow through between the tubes of the group of tubes of the heat exchanger closest to the burner inevitably hit the tubes of the group of tubes facing away from the burner and give off their heat to the tubes. In this way, the combustion gases are utilized to a very high degree, resulting in a correspondingly higher efficiency. It is also ensured that there is only a diffuse reflection of the heat radiation on the very structured wall of the heat exchanger, which is significantly less than with smooth walls, which results in less heating of the burner and thus less NO _x emissions. Furthermore, the radial flow of the combustion gases from the burner through the heat exchanger improves combustion compared to the previously usual essentially axial flow through the combustion chamber.

The features of claim 3 result in the advantage of a very simple construction.

The features of claim 4 result in the advantage of a very uniform flow to the tubes of the heat exchanger and thus also a uniform heating of the fluid flowing through the tubes.

The features of claim 5 result in a construction in which weld seams in those areas where the combustion gases impinge on the heat exchanger can be practically dispensed with. This largely avoids corrosion problems.

The features of claim 6 result in the advantage that the combustion gases hitting the water chamber are cooled very quickly and give off their heat to the water in the water chamber.

The features of claim 7 result in the advantage that the fluid flowing through the heat exchanger is heated very evenly. This also results in the advantage that the different loading of the pipes in the area of their webs and their legs evens out their temperature in different areas due to the thermal conductivity of the pipes, which are usually made of metal.

The features of claim 8 result in a counterflow within a group of pipes, which results in a very uniform heating of the fluid to be heated.

The features of claim 9 result in the advantage that the surface of the tubes facing the burner, in relation to their cross-section, is larger than with tubes with a circular cross-section. In addition, the rectangular cross-section of the tubes results in the advantage of increased turbulence of the

combustion gases flowing between the tubes and thus an improvement in heat transfer.

The features of claim 10 result in the advantage of a very simple construction.

The features of claim 11 result in an enlargement of the heat exchanger surface.

The features of claim 12 result in the advantage that the water heater can also be operated as a condensing boiler, whereby the proposed measures ensure good drainage of the condensate that occurs.

The features of claim 13 reduce the radiation of

Heat and thus a loss of energy. In addition, the

The proposed measures also prevent a further drop in the temperature of the exhaust gases.

In a water heater according to the preamble of claim 14, the cast iron boilers essentially form a closed combustion chamber, at one end of which there is an outlet opening for the combustion gases. This results in an essentially axial flow in the combustion chamber. In addition, the combustion chamber of the known solutions of the type mentioned at the beginning, which is essentially closed except for the outlet opening and has a very regular inner wall, leads to a relatively high reflection of the heat radiation from the burner on the walls of the combustion chamber, whereby the burner is heated up and there is an increased formation of

r. rr &Ggr;:· ^&Mgr; : UK

of No _x . This is particularly the case with burners with high heat radiation, such as radiant burners.

In order to avoid these disadvantages, it is advantageous if such a water heater has the characterizing features of claim 14.

The proposed measures ensure that the combustion gases flow out of the combustion chamber essentially radially. This results in a more even heat exchange than with axial flow through the combustion chamber, which also results in a high level of efficiency of the cast iron boiler. The outflow gap also has the advantage that the reflection of the heat radiation is limited, which reduces the heating of the burner.

The features of claim 15 result in the advantage of a very simple design of the boiler.

The features of claim 16 result in a particularly high utilization of the heat of the combustion gases, so that under certain circumstances condensate can also form.

A further possibility for a very extensive utilization of the heat of the combustion gases results from the features of claim 17.

The features of claim 18 result in the advantage of a very simple structure, whereby a very safe process of a

· · i

any condensate that may occur and at the same time an increase in the cross-section of the exhaust gas collection chamber is ensured.

In a water heater according to the preamble of claim 19, the characterizing features of claim 19 ensure that the combustion gases flow practically exclusively radially through the gaps between the cast elements. This results in a more even heat exchange than with axial flow through the combustion chamber, which also achieves a high level of efficiency of the cast element boiler and avoids the formation of hotter and cooler zones. In addition, the strong structuring of the boundary surrounding the burner and the gaps between the individual cast elements result in a very significant reduction in the reflection of the heat radiation from the burner on the walls surrounding them. This results in a noticeably lower heating of the burner compared to the known solutions of the cast element boilers mentioned at the beginning, in which the burner is surrounded by an essentially smooth wall of the cast elements, which leads to a reduction in NO _x emissions.

The features of claim 20 result in the advantage of a very even flow of the combustion gases around the cast elements. In addition, the perforated wall surrounding the burner is very strongly structured, which prevents reflections of the heat radiation.

U·

The features of claim 21 result in a corresponding enlargement of the heat exchange surfaces and thus an improvement in the heat transfer, whereby the combustion gases collect in the exhaust gas collection space between the outer walls of the cast elements and the inner wall of the shell of the chamber and flow out via the exhaust pipe.

The features of claim 22 result in the advantage of a very uniform flow through the gaps between the cast elements, since the resistances for the combustion gases are essentially the same for all possible flow paths.

The invention will now be explained in more detail using the drawing. Show:

Fig. 1 and 2 show a vertical and a horizontal section through a first embodiment of a water heater according to the invention,

Fig. 3 and 4 show a vertical and a horizontal section through a second embodiment of a water heater according to the invention,

Fig. 5 and 6 show a vertical and a horizontal section through a third embodiment of a water heater according to the invention,

Fig. 7 and 8 show a vertical and a horizontal section through a fourth embodiment of a water heater according to the invention,

Fig. 9a to 9f Longitudinal sections of various embodiments of pipes for the water heaters according to Figs. 1 to 8,

H üb

Fig. 9g to 9m Cross sections of the pipes according to Fig. 9a to 9f,

Fig. 10 is a cross-section through a fifth embodiment of a water heater according to the invention, comprising cast elements,

Fig. 11 is a longitudinal section through the embodiment according to Fig. 10,

Fig. 12 and 13 show a longitudinal and a cross-section through a sixth embodiment of a water heater according to the invention, comprising cast elements, and

Fig. 14 and 15 show a longitudinal and a cross-section through a seventh embodiment of a water heater according to the invention, comprising cast elements.

The same reference symbols indicate the same details in all figures.

The water heater 1 has a housing 2 in which there is a combustion chamber 7, which is provided with thermal insulation 3 on the outside of its casing 4. A burner 17, which is surrounded by a burner casing 18, projects into this combustion chamber 7 from above.

The burner 17 is supplied with a gas-air mixture via a mixture preparation 23, wherein the mixture preparation 23 comprises a blower 26 which can be supplied with gas and air via a gas supply 24 and an air supply 25.

An ionization electrode 20 for monitoring the flames and an ignition electrode 19 for igniting them also extend into the combustion chamber 7.

The combustion chamber 7 is closed at its top by a burner plate 22 which holds the burner 17 and is penetrated by the electrodes 19, 20 and is provided with an insulation 21.

The combustion chamber 7, or its base 117 or the base 118 of the casing 4, has an inclination 31 to the horizontal of approximately 3°, with a condensate drain 27 provided at the lowest point 119. The combustion chamber 7 is supported by supports 29 and 120 of unequal length. An exhaust pipe 28 is also connected to the combustion chamber 7.

In the embodiment according to Figs. 1 and 2, a deflection chamber 14 is arranged in the area of the burner plate 22, which surrounds it and through which the cooling medium can flow, and which is essentially ring-shaped.

Connected to this deflection chamber 14 are pipes 5 of a heat exchanger 42, distributed in two circles lying concentrically to the axis 121 of the cylindrical burner 17, the other ends of which are connected to a return chamber 12 or a flow chamber 15. The pipes 5, which are divided into two groups, as can be seen from Fig. 2, are arranged offset from one another, so that in the area of each gap 122 between two pipes 5 of one group, a pipe 5 of the second group is arranged. The pipes 5 are provided with fins 6.

the inner group of pipes 5, closer to the burner, is connected to the flow chamber 15, which is connected to a flow 9, and the other outer group of pipes 5, further away from the burner, is connected to the return chamber 12, which is connected to a return 10.

A return flow distributor 11 and a flow distributor 16 are provided, which serve to connect the return flow 10 to an outflow opening 32 arranged centrally to the axis 121 of the burner, or to connect the flow 9 to an inflow opening 33 which is also arranged centrally.

Stabilizing webs 13 are arranged in the flow chamber 15, whereby the flow chamber 15 is closer to the burner 17 than the return chamber 15, both of which are arranged as a cylinder chamber essentially perpendicular to the front side of the axis 121 of the burner 17.

Between the casing 4 of the combustion chamber 7 and the outer tubes 5 or their ribs 6, there remains an outer exhaust gas collection chamber 8, which is connected to the exhaust pipe 28.

The arrangement of the pipes 5 in the embodiment according to Figs. 1 and 2 ensures that the combustion gases that flow between two adjacent pipes 5 arranged in the inner circle impact the pipes 5 arranged in the outer circle and give off their heat there. Furthermore, the flow chamber 15 arranged essentially perpendicular to the axis of the burner 17 and the return chamber 12 located below it ensure that the heat of the combustion gases is optimally used for heating

of the water flowing through the heat exchanger 42 and the two chambers 12 and 15.

After flowing through the heat exchanger 42, the exhaust gases collect in the outer exhaust gas collection chamber 8 and then flow out via the exhaust pipe. Any condensate that may occur flows out via the condensate drain 27.

In the embodiment according to Figs. 3 and 4, the heat exchanger 42' is formed by two coiled tubes 5' and 34, which can be connected in series or parallel. The coiled tubes 5' and 34, which are provided with fins 6, are connected to a flow line 9 and a return line 10.

A water-cooled combustion chamber closure 30 is also provided, which is also connected to the flow line 9 and a return line 10 via lines 123, 124. In this case, a parallel connection of the pipe coils 5' and 34 and the combustion chamber closure 30 can be provided, or a series connection of these parts (first the outer pipe coil, then the inner and finally the combustion chamber! In the latter case, the arrangement of a deflection chamber would be necessary, or the pipe coils 5', -34 would have to be connected to one another via pipe bends.

The essential feature of this embodiment is the fact that the

Turns of the outer concentric to the axis 121 of the burner

arranged tube coils 5', 34 are arranged in the region of the gap between two turns of the inner tube coil 34.

In the embodiment according to Figs. 5 and 6, the heat exchanger 42" is formed by two pairs of groups of U-shaped tubes 5", 5"' and 35, 35' arranged next to one another, which are arranged essentially perpendicularly to one another. The webs 36 of the tubes 5", 5'" and the webs 37 of the tubes 35, 35' are perpendicular to one another.

One leg 38 of the pipes 5" and 35' are connected to a flow chamber 15, and the other leg of the pipes 5" and 35' are connected to a return chamber 12. The other leg 39 of the pipes 5" and 35' are connected to a flow chamber 12. The leg 40 of the pipes 5"' and 35' are also connected to this.

35. The legs 41 of the pipes 5'" and 35 are connected to the return chamber 15. This results in an opposing flow in each pair of pipes 5", 5" ¹ on the one hand and 35, 35' on the other.

The webs 37 and 36 of the tubes 5", 5'", 35, 35' replace the cooled combustion chamber closure 30, or the flow chamber 15 and the return chamber 12 according to Fig. 1 and 2.

In the embodiment according to Fig. 5 and 6, the webs run

36 of the tubes 5", 5'" above and below the webs 37 of the tubes 35, 35', whereby all tubes have a substantially circular cross-section.

The embodiment according to Figs. 7 and 8 differs from that according to Figs. 5 and 6 in that the tubes 5", 5'" and 35, 35' have a substantially rectangular cross-section.

In addition, the webs 36 and 37 of the tubes 5" and 5 ^/ir or 35 and 35' are arranged alternately one above the other, with the webs 37 of the tubes 35 being arranged closest to the burner 17.

It can be seen from Fig. 8 that the width of the tubes 5", 5'", 35, 35 ' is greater than the width of the gap 125 remaining between these tubes, so that the tubes arranged on te overlap one another.

Fig. 9a to 9m show different shapes of tubes 51 to 56. The tube 51 has a circular cross-section and is provided with fins 6. The tube 52 has an elliptical cross-section and is also provided with fins 6. Likewise, the tube 53, which has a rectangular cross-section, is provided with fins 6.

The tube 54 has a circular cross-section and, like the tubes 55 and 56, has a smooth outer casing, whereby the tube 55 has an elliptical cross-section and the tube 56 has a rectangular cross-section. These tubes correspond to the tubes shown in Figs. 1 to 8.

The embodiment according to Fig. 10 and 11 uses a boiler instead of a wall-mounted continuous flow or circulating water heater. The cast iron boiler 126 is arranged in a housing 61 and has a series of cast iron elements 62 which are arranged next to one another and are hydraulically connected to one another in their upper region.

The cast members 62 have a substantially keyhole-shaped recess 63, with the circular arc-shaped areas 64 of the keyhole-shaped recesses 63 defining a combustion chamber 65 which is closed off at its upper end by a combustion chamber closure 67 which is perpendicular to the longitudinal axis 121 of a radiant burner 66. The hollow burner closure 67 is hydraulically connected to the cast members 62.

A flow line 68 is connected to this burner outlet 67.

Below the legs 81 and 127 of the cast members 62, which are separated from one another by the keyhole-shaped recess 63, there are further cast members 69, which are connected in series with one another via a bend 70. Between the legs 81 and the further cast members 69, there remain gaps 71, each running in a horizontal plane, in which the outflowing combustion gases can be distributed, whereby the combustion gases can flow out of the combustion chamber 65 via an outflow gap 72 extending over the length of the combustion chamber 65 in its axial direction. The outflow gap 72 is located in the transition area between the circular arc-shaped area 64 of the keyhole-shaped recess 63 and its slot-shaped area.

Below the cast elements 69 there is an exhaust gas collection chamber 73, the cross-section of which increases in the direction of an outflow opening 74. This results in the increase in the cross-section

of the exhaust gas collection chamber 73 by a sloping floor 75, at the lowest point of which a condensate drain 76 is arranged.

A return line 77 is connected to the cast member 69 arranged in the area of the end of the combustion chamber 65.

The combustion chamber 65 is closed at one end opposite the cast member 62 by a combustion chamber closure 67, in which the radiant burner 66 is held, which can be supplied with a gas-air mixture via a fan 80.

The embodiment according to Figs. 12 and 13 differs from that according to Figs. 10 and 11 in that the additional cast members 69 arranged below the legs 68 of the cast members 62 are omitted and replaced by a finned heat exchanger 78. In this case, several heat exchanger tubes 79 connected in series are arranged below the cast members 62 and connected to one another via elbows 70. The heat exchanger tubes 79 are arranged in three rows, with the heat exchanger tubes 79 in the individual rows being arranged offset from one another and the finned heat exchanger 78 being connected to a return line 77.

The arrangement of an outflow gap 72 over the entire length of the combustion chamber 65 results in a radial outflow of the combustion gases, which leads to a very extensive utilization of the heat of the combustion gases and a very uniform heating over the length of the combustion chamber 65, or in the cast elements 62

flowing water. In addition, there is a reduction in the reflection of the heat radiation from the burner 66 on the inner walls of the cast elements 62 arranged in a row, so that the burner 66 heats up less than in known solutions.

The water heater according to Figures 14 and 15 has a chamber 110 in which cast members 92 are arranged, which are essentially toroidal in shape. A cylindrical radiant burner 96 is arranged in the center of the cast members 92, whereby the cast members 92 are arranged at a distance from one another in the longitudinal direction of the burner 96, so that a gap 102 is formed between each two cast members 92.

The cast members 92 are provided with ribs or knobs 111 which extend essentially in the radial direction and protrude in the longitudinal direction of the burner 96, which protrude into the gap 102 and improve the heat transfer from the combustion gases to a heating medium, usually water, flowing through the cast members 92. The axial distance between the cast members 92 is determined by supports 116 (Fig. 15) and the connecting channels 115 which run in nipples.

The individual cast elements 92 are connected in series with one another on the water side, with the connecting channels 115 being arranged offset by 180° from one cast element to another 92. The lowest cast element 92 is connected to a return line 107 and the uppermost cast element 92 to a flow line 98. However, elements can also be connected in parallel on the water side.

The burner 96 is held in a flat front wall 112 at the top. A casing 113 of the essentially cylindrical chamber 110 delimits an exhaust gas collection chamber 103, which surrounds the cast elements 92 at a distance. The combustion gases collect in this after flowing radially out of the area immediately surrounding the burner 96, flowing through the gaps 102 between the cast elements 92. The combustion gases can then flow out via the discharge opening 104 arranged centrally in the conical second front wall 114 at the bottom, e.g. into a chimney. Any condensate that may arise can also flow out in a collected manner.

In the area of the lowest cast member 102, a plate 97 is arranged which forms a closure 97 of the combustion chamber and covers the essentially cylindrical combustion chamber 95 enclosed by the cast members 102 perpendicular to the burner longitudinal center axis 121. This ensures that the combustion gases can only flow radially from the burner 96 and practically no flow can form in the longitudinal direction of the burner 96 within the cast members 102. Such an axial flow of the combustion gases can only form in the area of the exhaust gas collection chamber 103.

Claims (22)

rl &igr; Joh. Vaillant GmbH u. Co GM 1436 PATENT CLAIMS. 1. Water heater with a burner (17, 66, 96) arranged in a combustion chamber (7, 65, 95) and a heat exchanger which has at least one cavity through which a medium to be heated can flow and which is connected to a return line (10) and a flow line (9), characterized in that the burner (17, 66, 96) is surrounded by parts (5, 5', 5", 5'", 35, 35', 62, 92) of the heat exchanger while maintaining a gap, these parts of the heat exchanger being connected to one another via sections (30, 36, 37, 67, 95) running essentially perpendicular to the axis of the burner (17, 66, 96). 2. Water heater according to claim 1, characterized in that the parts (5, 5', 5", 5'", 35, 35') of the heat exchanger surrounding the burner (17) are formed by two concentrically spaced apart from the jacket (4) of the combustion chamber (7). arranged groups of louvre tubes (5, 5', 5", 5'", 35, 35'). 3. Water heater according to claim 1 or 2, characterized in that the pipes (5, 5', 5", 5 ^/ir , 35, 35') are aligned parallel to the burner axis and one end of which is connected to an annular deflection chamber (14) and the other end of which is connected to a feed chamber (15) which is substantially perpendicular to the burner axis and from which a feed line (9) leads, or a return chamber (12) into which a return line (10) opens. 4. Water heater according to one of claims 1 to 3, characterized in that the outlet opening (32) of the return line (10) in the return chamber (12) and the inflow opening (33) of the flow line (9) in the flow chamber (15) which are arranged one behind the other in the direction of the burner axis, are arranged essentially centrally or in the burner axis, wherein the outflow opening (32) or the inflow opening (33) are optionally connected to eccentrically arranged connecting pieces via a radially extending distributor (11, 16). 5. Water heater according to claim 1 or 2, characterized in that in the combustion chamber (7) two Coaxial and centrally arranged pipe coils (5', 34) to the burner axis are arranged, which are connected to flow and return lines (9, 10). 6. Water heater according to claim 5, characterized in that a cooled burner closure (30) is provided which is perpendicular to the burner axis and is connected to a flow line and a return line (9, 10). 7. Water heater according to claim 1 or 2, characterized in that a first pair of groups of U-shaped bent pipes (5", 5'"; 35, 35') arranged next to one another is provided in the combustion chamber (7), one end of which is connected to a flow chamber (15) and the other end of which is connected to a return chamber (12), a second pair of groups of U-shaped bent pipes (35, 35') arranged next to one another, the webs (37) of which run perpendicular to the webs (36) of the first pair of groups (5", 5'") being provided, which are also connected to the flow chamber (15) or the return chamber (12) and the webs (36, 37) of these pipes (5", 5'", 35, 35') run essentially perpendicular to the burner axis. 8. Water heater according to claim 7, characterized in that the legs (38) of a pair of tubes (35, 35') running on one side of the combustion chamber (7) are connected to different chambers (12, 15) connected to a flow or return line (9, 10). 9. Water heater according to claim 7 or 8, characterized in that the tubes (52, 5", 5'", 35, 35') have a rectangular cross-section. 10. Water heater according to one of claims 7 to 9, characterized in that for each pair of groups of tubes (5", 5"'_; 35, 35') a flow chamber and a return chamber (12, 15) are provided. 11. Water heater according to one of claims 1 to 10, characterized in that the tubes (5, 5', 5", 5'", 35, 35') are provided with fins (6). 12. Water heater, characterized in that the bottom of the combustion chamber (7) is inclined to the horizontal by approximately 3°. 13. Water heater according to one of claims 1 to 12, characterized in that the combustion chamber (7) is provided on its outside with a thermal insulation (3). 14. Water heater according to claim 1, in which hydraulically interconnected cast members (62) are provided as heat exchangers, and in which a combustion chamber closure extending substantially perpendicular to the longitudinal axis of the burner (66) through which the heating medium flows is provided, characterized in that in the region of the cast members (62) an outflow gap (72) extending over the length of the burner (66) is provided for the combustion gases, which opens into an exhaust gas collection chamber (73) whose cross-section increases in the direction of an outflow opening (74). 15. Water heater according to claim 14, characterized in that the cast members (62) have an open-edged, substantially keyhole-shaped recess (63). 16. Cast iron boiler according to claim 14 or 15, characterized in that further cast iron members (69) are arranged adjacent to the legs (81) of the cast iron members (62) spaced apart from one another by the keyhole-shaped recess (63), which are hydraulically connected to the cast iron members (62) partially surrounding the burner (66). 17. Cast iron boiler according to claim 14 or 15, characterized in that a plate heat exchanger (78) is arranged in the region of the exhaust gas collecting chamber (73), which is hydraulically connected to the cast iron members (62). 18. Cast iron boiler according to one of claims 14 to 17, characterized in that the bottom (75) of the exhaust gas collection chamber (73) runs obliquely downwards towards the outflow opening (74) and a condensate drain (76) is optionally arranged at the lowest point. 19. Water heater according to claim 1, in which hydraulically interconnected cast members (92) are provided as heat exchangers, and in which a combustion chamber closure extending substantially perpendicular to the longitudinal axis of the burner (96) through which the heating medium flows is provided, characterized in that in the region of the cast members (92) surrounding the burner (96) at least one gap (102) is arranged which enables a radial outflow of the combustion gases and which establishes a connection with an exhaust gas collection chamber (103). 20. Water heater according to claim 19, characterized in that the cast members (92) are substantially toroidal and • · &Ggr;-.&lgr; m &Lgr;&Lgr; · * ^m. &Lgr; are arranged at a distance from one another in the longitudinal direction of the burner (96) by gaps (102) and surround the burner (96), whereby between the outer wall of the cast elements (92) and the inner wall of the casing (113) of the chamber (110) the exhaust gas collection chamber (103) is provided, which is connected to an outflow opening of the chamber (110) and the combustion chamber closure (97) is formed by a plate which covers the combustion chamber (95) delimited by the cast elements (92). 21. Water heater according to claim 19 or 20, characterized in that the cast members (92) are provided with knobs (111) or ribs projecting in the axial direction of the burner (96), the latter being radially aligned, between which outflow channels (102) for the combustion gases remain. 22. Water heater according to one of claims 19 to 21, characterized in that an outflow opening (104) is arranged centrally on an end face (114) of the chamber (HO), the corresponding end wall (114) preferably being conical.