DE10236665A1 - Gas-liquid heat exchanger for a boiler has modular heat exchanger plates for the heat exchange between a gas and a heat carried liquid - Google Patents

Abstract

Gas-liquid heat exchanger (3) has several modular heat exchanger plates (4) for the heat exchange between a gas and a heat carried liquid. Each plate comprises a hollow body, a section provided with heat exchanger elements; and a passage (21) for the gas flow. The hollow body has an inlet opening (13) and an outlet opening (15) for the liquid, a first channel (22) extending in a direction between the proximal end (11) and a distal end (23) of the plate to convey the heat carried liquid, and a second channel arranged in series with the first channel. The plates are arranged in a packet arrangement.

Description

The invention relates to a gas-liquid heat exchanger with several modular Heat exchanger plates which exchange heat between a gas and one Can cause heat transfer fluid, the heat exchanger preferably, but not restrictive, used in boilers, for example in premix boilers and condensation boilers becomes.

The invention also relates to a boiler equipped with such a heat exchanger is, and a modular heat exchanger plate, which is suitable for the described To effect heat exchange.

As is common in the field of gas-liquid or air-liquid heat exchangers is known, particularly in the field of gas-water heat exchangers for boilers of the most pressing needs, highly effective heat exchangers to get reduced costs.

For this purpose are gas-liquid heat exchangers with several modular plates that made in one piece from cast iron by pouring into a mold around a clay core and to be assembled to each other in packages, has been known for a long time. Each plate is essentially of a body with a plurality of mutually structurally independent lines formed extend parallel to each other between opposite ends of the plate. In particular, these lines convey the liquid from a liquid inlet opening in the plate, which is formed in a collecting tube arranged at the first end of the plate, into one Outlet opening of the liquid from the plate in a collecting tube on the opposite End of plate. Furthermore, the lines are generally with ribs to enlarge the Provide heat exchange surface between the gas and the liquid.

Heat exchangers of this type are generally used in boilers that have one have atmospheric burner, and are mounted above it. In this case the gas is through the combustion gases are formed and the heat transfer fluid is water. In this way are a substantially zigzag liquid flow path (its horizontal Sections are divided into several parallel branches that are formed in the plate lines are) and a gas flow path is formed, which the heat exchanger plates in vertical Directionally interspersed from bottom to top.

In the description and the following claims, the terms refer to "low" and "high", "lower" and "upper", "below" and "above", "horizontal" and "vertically" on the modular plates, the heat exchanger and the boiler as well as on their Components in relation to their position in the assembled state.

Regardless of the large heat exchange area, which is caused by the ribs of each plate is provided, have heat exchangers of this type, as well as the boilers equipped with them Problems that have not yet been solved.

First, the parallel arrangement of the lines for fluid circulation creates in each Heat exchange plate on the one hand a reduced liquid speed with a corresponding drop in heat exchange efficiency and secondly the Possibility that local temperature changes can occur, for example due to overheating an uneven distribution of the liquid flow in the different lines with negative effects on the life of the heat exchanger.

Second, have gas-liquid heat exchangers, which are through the plates described large dimensions due to the presence of liquid Collecting tubes which are arranged at the opposite ends of the plates as mentioned.

Third, dry cleaning, which was judged to be the most effective, proved to be extremely difficult to accomplish because the cleaning fluids used for this purpose tend to flow preferentially through those lines which have the least Provide drag, d. H. the least polluted lines, and on Cost of those lines that need more cleaning.

The technical problem underlying the invention is therefore one To provide heat exchanger that has a high heat exchange efficiency and overcomes the disadvantages of the prior art.

• a) einen im wesentlichen plattenförmigen Hohlkörper, der einstückig aus Gießmetall gefertigt ist und aufweist:
  • 1. eine Einlaßöffnung und eine Auslaßöffnung für die Flüssigkeit in den und aus dem Hohlkörper, wobei die Einlaß- und Auslaßöffnungen an einem proximalen Ende der modularen Platte ausgebildet sind;
  • 2. mindestens einen ersten Kanal, der sich in einer ersten Richtung zwischen dem proximalen Ende und einem distalen Ende der modularen Platte zum Fördern der Wärmeträgerflüssigkeit von der Einlaßöffnung zu dem distalen Ende erstreckt;
  • 3. mindestens einen zweiten Kanal, der in Reihe mit dem ersten Kanal angeordnet ist und sich in der ersten Richtung zwischen dem distalen Ende und dem proximalen Ende der modularen Platte zum Fördern der Wärmeträgerflüssigkeit von dem distalen Ende zu der Auslaßöffnung erstreckt;
• b) mindestens einen mit mehreren Wärmetauschelementen versehenen Abschnitt, die freikragend von dem Hohlkörper wegragen, um die Wärmeaustauschfläche zwischen dem Gas und der Wärmeträgerflüssigkeit zu vergrößern;
• c) mindestens einen Durchlaß zum Ermöglichen einer Gasströmung, der den Hohlkörper passierend geformt ist, wobei mindestens ein Teilbereich des Abschnittes mit Wärmetauschelementen bestückt ist,

wobei die modularen Platten jeweils paketweise so montiert sind, daß sie einen Flüssigkeits- Strömungspfad und einen Gas-Strömungspfad im Wärmetauscher bilden und die Flüssigkeits- Strömungspfade und die Gas-Strömungspfade mindestens teilweise einander kreuzen. According to the first aspect of the invention, said technical problem is solved by a gas-liquid heat exchanger with a plurality of modular heat exchange plates which can bring about a heat exchange between a gas and a heat transfer liquid, each modular plate comprising:

• a) an essentially plate-shaped hollow body which is made in one piece from cast metal and has:
  • 1. an inlet opening and an outlet opening for the liquid into and out of the hollow body, the inlet and outlet openings being formed at a proximal end of the modular plate;
  • 2. at least a first channel extending in a first direction between the proximal end and a distal end of the modular plate for conveying the heat transfer fluid from the inlet opening to the distal end;
  • 3. at least one second channel arranged in series with the first channel and extending in the first direction between the distal end and the proximal end of the modular plate for conveying the heat transfer fluid from the distal end to the outlet opening;
• b) at least one section provided with a plurality of heat exchange elements which project cantilevered from the hollow body in order to enlarge the heat exchange surface between the gas and the heat transfer fluid;
• c) at least one passage for permitting a gas flow, which is shaped to pass through the hollow body, at least a partial area of the section being equipped with heat exchange elements,

wherein the modular plates are each packaged so that they form a liquid flow path and a gas flow path in the heat exchanger and the liquid flow paths and the gas flow paths at least partially cross each other.

In the description and in the following claims, the expression is intended "Heat exchange elements" refer to components that project freely from the plates and such a shape and size so that they have the heat exchange surfaces between the gas and the liquid enlarge. As a non-limiting example, such heat exchange elements frustoconical or cylindrical or essentially rib-shaped or fin-shaped his.

In the description and in the following claims, the terms "proximal" and "distal" denote those parts of the modular plate and heat exchanger that near and on opposite sides of the inlet and outlet openings of the Liquid is arranged in and out of the plate.

Thanks to the fact that the first and second channels formed in the hollow body in series are interconnected, it is advantageously possible to have a larger one Flow velocity and greater turbulence of the heat transfer fluid compared to that To achieve heat exchangers according to the prior art, which leads to an increase in the Heat exchange coefficient on the liquid side and, as a result, an increase in Overall efficiency of the heat exchanger leads.

In addition, the heat exchange efficiency is compared to that with conventional heat exchangers can be achieved, thanks to the fact that the Liquid and gas flow paths in the heat exchanger at least partially in Cross-flow relationship to each other. This increase in heat exchange efficiency is to thank essentially all modular heat exchange plates, which the Heat exchangers form, with the exception of the plate that is in operation the first of the gas flow around plate, for example in the form of the combustion gases of a burner, because at this plate, the gas flow is only partially across, d. H. in cross flow to the direction of flow Heat transfer fluid flows.

Since the inlet and outlet openings of the liquid in and out of each modular plate of the Heat exchanger according to the invention at the same end of the plate (the proximal end) are arranged, the heat exchanger of the invention advantageously has only one Series of manifolds for the heat transfer fluid, these manifolds on one single side (the proximal side) of the heat exchanger are stacked in packets.

The heat exchanger according to the invention is therefore more compact than the conventional one Heat exchanger of the same heat output, which two rows of manifolds on the need opposite ends of the plate.

Furthermore, the series arrangement of the first and second channels in the hollow body enables the Plates the effective chemical cleaning of these channels using suitable ones Cleaning fluids, for example aqueous hydrogen chloride solutions in an advantageous manner.

According to a preferred embodiment of the invention, the liquid Flow path in the heat exchanger is essentially in a zigzag path between an inlet opening and an outlet opening of the heat transfer fluid in and out of Heat exchanger and runs at least partially in each modular plate in the first Direction.

Preferably, the inlet and outlet openings of the liquid are in and out of the modular plates in corresponding, structurally independent inlet and outlet chambers trained, which are liquid-tightly separated from each other and with a single manifold are equipped, which extends in one piece from the proximal end of the modular plate.

In this way, it is advantageously possible to very easily close the modular panels together connect, d. H. simply in that the outlet opening of a plate and the inlet opening the adjacent plate is placed side by side on the proximal side of the heat exchanger become.

The modular plates are preferably reciprocal and fluid-tight on the liquid Collector lines attached, even cheaper on their peripheral edges thanks to the Use of suitable circumferential sealants, such as in the form of between sealing strips between adjacent plates.

According to a preferred embodiment of the heat exchanger according to the invention, the mentioned at least one first channel in the hollow body near that of a side wall arranged while the second channel is opposed in the hollow body near a side wall the first channel is arranged.

Thanks to this combination of preferred features, it is advantageously possible to use a fluid To create flow path that not only maximum the available volume of the hollow body every single heat exchanger plate, but also an excellent one Heat exchange with the gas flowing around the plate causes.

The hollow body preferably also contains an intermediate channel which is in series with the first and second channels is arranged. This additional intermediate channel enables another Increase in the utilization of the available volume in the hollow body while at the same time Extension of the fluid flow path in each plate with a resulting one Increasing the heat exchange efficiency of the heat exchanger.

According to a further preferred embodiment, the intermediate channel mentioned is in the designed essentially zigzag-shaped and extends along the transverse central plane of the modular Plate. In this way, the available volume in the hollow body is maximized, resulting in leads to a further increase in the heat exchange efficiency.

According to another advantageous embodiment, the at least one channel in the Hollow body may be arranged near the first end face, while the second channel preferably formed in the hollow body near the other end face opposite the first channel is.

In this alternative embodiment, the first channel, the second channel and the intermediate partition preferably a width which is substantially the width of the corresponds to at least one section with the heat exchange elements of the modular Plate is equipped. In this way, a maximum heat exchange area is related to achieved the size of the plate in an advantageous manner.

The mentioned at least one section is preferably a plurality Provide heat exchange elements that protrude from opposite end faces of the hollow body.

This preferred embodiment allows an advantageous increase in the available Heat exchange surface for the between the plates of the heat exchanger in cross or cross flow to achieve flowing gas.

The said at least one section is preferably the one with the plurality Is provided heat exchange elements, at a predetermined angle with respect to the transverse median plane of the modular plate. In this way the outflow becomes possible Condensation water along the plane formed by each plate facilitated and thus the Optimized heat exchange and at the same time protected the plates from corrosion.

This angle is preferably between approximately 2 ° and approximately 4 °.

Preferably, the heat exchange elements are essentially staggered in several rows arranged parallel to the longitudinal axis of the modular plate.

The division between the heat exchange elements in each row is preferably between about 8 mm and about 20 mm.

In this way it is advantageously possible to have a large heat exchange surface ensure while minimizing the risk of local thermal gradients, resulting in a even distribution of heat and, as a result, an extended lifespan of the Heat exchanger leads.

The rows mentioned are preferably staggered in the direction essentially perpendicular arranged to the longitudinal axis of the modular plates. The division between the rows of Heat exchange elements is about 8 mm to about 20 mm.

Preferably the modular panels comprise a first and a second group of rows of Heat exchange elements, these groups on opposite sides of the longitudinal axis of the modular panels are arranged.

In addition, the rows of the first group are preferably in relation to the rows of the second group in the direction substantially parallel to the longitudinal axis of the modular plate offset, namely by a length corresponding to half the division of the heat exchange elements the second group.

Thanks to this arrangement of the heat exchange elements, it is as follows more clearly, advantageously, the heat exchanger is constructed constructively by assembling several to build identical modular panels: the described arrangement of the In fact, heat exchange elements allow the use of such elements between those of one adjacent plate by turning the plate about its longitudinal axis. In other words, everyone Plate about its longitudinal axis through an angle of 180 ° with respect to the adjacent plate from bottom up.

In this way, the heat exchanger according to the invention allows an advantageous one Saving in manufacturing costs while avoiding the need for storage different plate types.

Furthermore, thanks to such an arrangement, two further advantages can be achieved simultaneously which consist in providing an extremely compact heat exchanger and that the heat exchanger has a uniform velocity of gas flow causes. In other words, it is advantageously possible to have a uniform one Heat distribution along each heat exchange element and thus an improvement in both Heat exchange efficiency of a heat exchanger according to the invention as well as its To achieve lifespan.

The heat exchange elements preferably have an angle of inclination of approximately 2 ° to approximately 5 °.

In this description and the following claims, the term denotes "Tilt angle" of a heat exchange element between the lateral surface of a Heat exchange element and the angle existing perpendicular to the body of the modular plate.

According to a preferred embodiment of the invention, the heat exchange elements in essential frustoconical shape.

Thanks to the manufacturing technology used (sand casting), it is advantageously possible to reduce this angle of inclination up to the specified values, which is an advantageous Reducing the thickness of the gap between the adjacent heat exchange elements modular panels.

According to a preferred embodiment, this gap forms part of the gas flow path crosses the heat exchanger, this gap having a substantially constant thickness.

This thickness is preferably between about 1 mm to about 3 mm.

Thanks to the frustoconical shape of the heat exchange elements, this is also possible The flow of possible condensed water from one plate to another is facilitated and thus the Efficiency of the boiler optimized, while at the same time protecting the panels from the risk of Corrosion are protected. Consequently, the heat exchanger according to the invention can be advantageous Way to recover heat in condensation boilers.

Preferably said passage is to allow gas flow through the Hollow body of the modular plate formed near the side wall.

Thanks to this feature, the panels can be assembled according to the above Method (i.e. by turning the plates 180 ° from bottom to top with respect to adjacent plates) achieving a substantially zigzag gas flow path in the heat exchanger what essentially the gas flow in transverse or Cross flow directs to the direction of the heat flow path, causing the Heat exchange between the gas passing through the plates and the gas flowing in the plates Liquid is maximized.

The gas flow path preferably extends at least partially between adjacent ones modular panels along a second, substantially perpendicular direction to the first and second channels in the modular panels.

Thanks to this orientation of the gas flow path, the drainage becomes everyone, himself possible condensate advantageously facilitated.

In a second aspect, the invention provides a boiler that includes a burner and has a heat exchanger as described above.

The burner is preferably of the so-called premix type, and the heat exchanger is supported below the burner, so that the latter is protected from coming into contact with possible condensate.

The modular plates of the heat exchanger are preferably made by casting metals manufactured with different heat resistance and assembled so that the modular Metal plates with greater heat resistance are placed closer to the burner.

The modular plates of the heat exchanger are preferably made by casting metals manufactured with different corrosion resistance and assembled so that the modular Metal plates with less corrosion resistance placed closer to the burner are.

Due to the last described versions of the burner according to the invention, in advantageously a reduction in material costs when using materials achieved the highest quality, with increased temperature and / or corrosion resistance is only achieved where necessary.

Preferably, the boiler according to the invention comprises a collecting pipe for collecting the Condensate, which manifold is positioned downstream of the heat exchanger.

According to a third aspect, the invention provides a modular heat exchanger plate, which a heat exchange between a gas and a heat transfer fluid with the Features described above can cause.

Additional features and advantages of the invention will be apparent from the following description a preferred embodiment with reference to the accompanying drawings, the same Reference numerals designate identical or equivalent parts.

Show it:

Figure 1 is a schematic cross section of a boiler with a heat exchanger according to the invention.

FIG. 2 is a view of a modular plate of the heat exchanger according to FIG. 1;

Fig. 3 is a plan view of the modular plate of Fig. 2;

FIG. 4 shows a cross section along the line II in FIG. 3 of the modular plate according to FIG. 2;

Fig. 5 is a side view, partly in section along the line II-II in Fig. 3, of the modular plate according to Fig. 2;

Fig. 6 is a section along the line III-III in Figure 5 of the modular panel of Fig. 2.

Fig. 7 is a cross section of a portion of the heat exchanger of Fig. 1 comprising a pair of modular plates cut along the line IV-IV in Fig. 3.

According to Fig. 1 is a boiler with a burner 2, for example, a burner of the premixing type, as well as, generally indicated with a heat exchanger 3 according to a preferred embodiment of the invention, which is supported in known manner by the reference numeral 1.

The heat exchanger 3 comprises a plurality of structurally identical modular plates 4 which are assembled in a packet-like manner. The modular plates 4 effect heat exchange between the combustion gases emerging from the burner 2 and a suitable heat transfer fluid, for example water.

As shown in FIG. 1, the boiler 1 includes a combustion zone 5 downstream of the burner 2 . The combustion zone 5 is fed with combustion air from a fan 6 and with a combustible gas from a gas line 7 , which is provided with a shut-off valve 8 . The combustion air and the combustible gas are intimately mixed by means of a Venturi tube 9 .

Referring to FIG. 1, the heat exchanger 3 includes three modular plates 4, the fluid-tightly and reciprocally at respective headers 10 for distributing and collecting the heat transfer fluid into and out of the panels 4 are associated with each other. Each manifold 10 integrally protrudes from a proximal end 11 of each modular plate 4 and includes an inlet opening 13 and an outlet opening 15 of the liquid into and out of the plate 4 .

Furthermore, each modular plate 4 comprises an opening 21 for allowing a gas flow, which will be explained in more detail below. Between each pair of adjacent modular plates 4 there is a gap 45 which is intended to allow gas flow and forms part of a gas flow path G in the heat exchanger 3 ( FIG. 7).

A return line 12 for conveying the heat transfer fluid back into the heat exchanger 3 is connected to the heat exchanger 3 in a manner known per se and is in fluid communication with the inlet opening 13 of the modular plate 4 , which is arranged in the lowest position. A feed line 14 for discharging the heat transfer fluid from the heat exchanger 3 is in fluid communication with the outlet opening 15 of the modular plate 4 , which is arranged in the highest position.

The boiler 1 also has an exhaust pipe 16 for discharging the combustion gases from the heat exchanger 3 and a collecting pipe 17 for collecting the condensate. The exhaust pipe 16 and the manifold 17 are arranged downstream of the heat exchanger 3 .

Thus, a liquid flow path L is formed in the heat exchanger 3 , which extends substantially in a zigzag shape between the inlet opening 13 and the outlet opening 15 for the heat transfer fluid into and out of the heat exchanger 3 , and furthermore the mentioned gas flow path G formed in the heat exchanger, which also extends essentially in a zigzag shape and essentially crosses the liquid flow path L, which is formed between the plates 4 . In particular, the liquid flow path L extends at least partially in each plate in the direction essentially parallel to the longitudinal axis XX of the plate 4 : this section of the liquid flow path L is generally designated by the letter L 'in FIG. 6.

Thanks to the arrangement of the heat exchanger 3 in the boiler 1 , possible condensate can easily be discharged through the heat exchanger 3 and collected in the collecting pipe 17 .

The modular plates 4 of the heat exchanger 3 are preferably made of casting materials of different heat and corrosion resistance. In particular, the modular plates 4 , which are positioned near the burner 2 , are made of metal materials of higher heat resistance, for example cast iron, while the modular plates 4 , which are most distant from the burner 2 , where there is a greater risk of corrosion, are made of metal materials highest quality and thus higher corrosion resistance, for example aluminum.

Fig. 2 shows a perspective view of the modular heat exchanger plate 4.

According to the invention, the modular plate 4 comprises a substantially plate-shaped hollow body 18 , which is made in one piece from cast metal, such as cast iron, which is cast in the so-called "sand casting process" in a mold around a core, which is preferably made from a conventional mixture of sand and Resin is made.

The modular plate 4 comprises at least one section which is provided with a plurality of heat exchanger elements 20 which project cantilevered from the hollow body 18 in order to increase the heat exchange area between the combustion gases and the heat transfer fluid, and with the passage 21 mentioned to enable gas flow through the hollow body 18 to the side of section 19 .

As described in detail with reference to FIGS. 4 and 5, the inlet and outlet openings 13 , 15 for the liquid in and out of the hollow body 18 according to the invention are formed on a proximal end 11 of the modular plate 4 .

As shown in FIG. 6, the hollow body 18 comprises at least a first channel 22 which extends in a first direction substantially parallel to the longitudinal axis XX of the plate 4 between the proximal end 11 and a distal end 23 of the plate 4 for conveying the heat transfer fluid extends from the inlet opening 13 to the distal end 23 , and at least one second channel 24 , which is connected in series with the first channel 22 and also extends along said direction between the distal end 23 and the proximal end 11 for conveying the heat transfer fluid from the distal end 23 extends to the outlet opening 15 .

According to the preferred embodiment shown in FIG. 6, the first channel 22 is arranged in the hollow body 18 next to its side wall 25 and between this wall 25 and an inner wall 26 .

The second channel 24 is preferably arranged in a hollow body 18 next to the side wall 27 lying opposite the first channel 22 .

In the preferred embodiment shown, the second channel 24 is arranged between the side wall 27 and a partition wall 28 which extends in the hollow body 18 .

At the proximal end 11 , the first channel 22 and the second channel 24 are separated in a liquid-tight manner by means of a wall 29 which extends between the wall 27 and the partition wall 28 .

According to the preferred embodiment according to FIG. 6, the hollow body 18 further comprises an intermediate channel 30 , which is arranged in series with the first channel 22 and the second channel 24 and advantageously permits an extension of the liquid flow path L 'in each plate 4 and thus the effectiveness of the heat exchanger 3 is increased.

The intermediate channel 30 preferably runs in a zigzag shape along the transverse central plane π of the modular plate 4 thanks to a plurality of inner partition walls 31-34 of predetermined length, the partition walls 31-34 all running parallel to the longitudinal axis XX and alternatively from an inner proximal wall 35 and protrude from an inner distal wall 36 of the hollow body 18 .

In order to increase the heat exchange area, the channel formed by the first channel 22 and the intermediate channel 30 arranged in series therewith preferably has an overall width which is substantially equal to the width of the section 19 which is provided with the heat exchange elements 20 of the modular plate 4 .

According to this preferred embodiment of the invention, as shown in FIGS . 4 and 5, the inlet opening 13 and the outlet opening 15 of the liquid into and out of the modular plate 4 are in structurally independent inlet and outlet chambers 37 , 38 which are liquid-tight from each other are separated, for example by a partition 39 , and formed in the manifold 10 of the modular plate 4 .

The modular plate 4 preferably comprises a plurality of tubular elements 40 which protrude from the wall 36 and are formed in the casting process around supporting elements of the core (technically referred to as "core supports") in order to enable the modular plate 4 to be produced. The tubular elements 40 have the function of allowing, the withdrawal of the modular plate 4 from the manufacturing mold and then removing the core from the modular plate 4 to. When the manufacturing process is complete, the tubular elements 40 are sealed by means of caps 41 , which are shown schematically in FIG. 3.

According to the preferred embodiment shown, the section 19 with the heat exchange elements 20 extends on opposite sides 42 , 43 of the hollow body 18 in order to enlarge the heat exchange area.

The section with the heat exchange elements 20 is moreover preferably inclined by an angle α approximately equal to 3 ° with respect to the transverse central plane π of the modular plate in order to facilitate the outflow of possible condensation water.

The heat exchange elements 20 are preferably staggered at a distance from one another, with an offset corresponding to a division p 'in a corresponding number of rows 20 a- 20 g, which run essentially parallel to the longitudinal axis XX of the modular plates 4 , in order to distribute the heat as uniformly as possible to achieve.

According to a preferred embodiment, the modular panels 4 comprise a first group 20 'rows and a second group 20 "rows of heat exchange elements 20 which are arranged on opposite sides of the longitudinal axis XX, the rows 20 a- 20 c of the first group 20' parallel are offset to the longitudinal axis XX with respect to the rows 20 d- 20 g of the second group 20 "by a length s which corresponds essentially to half the pitch p 'of the heat exchange elements 20 of the second group 20 " ( FIG. 3).

Such an arrangement of the heat exchange elements 20 allows an advantageous arrangement side by side of the modular plates 4 of the same type.

Preferably, the rows are 20 a- 20 g of the heat exchange elements 20 staggered from each other in a direction substantially perpendicular to the longitudinal axis XX of the modular plate 4 is arranged. In Figure 3 is the corresponding offset or the pitch between the rows 20 a- 20 g denoted by the letter p ".

According to FIG. 7, which shows a section of the heat exchanger 3 with two modular plates 4 arranged side by side, the heat exchanger can be packaged by placing a first modular plate and then placing a second structurally identical plate 4 , which, however, beforehand by an angle of 180 ° was turned around its longitudinal axis XX from bottom to top, to be built adjacent to the first plate 4 .

In this way, it is advantageously possible to arrange the heat exchange elements 20 of adjacent plates 4 reciprocally in order to create a gap 45 of essentially constant thickness.

The passage 21 is preferably arranged near a side wall in order to enable a gas flow, in the illustrated case near the side wall 25 of the hollow body 18 of the modular plates 4 .

Consequently, two substantially cross-flow or cross-flow paths are formed between adjacent plates 4 , the liquid flow path L being substantially zigzag-shaped between the inlet opening 13 and the outlet opening 15 of the liquid into and out of the heat exchanger 3 with sections runs, which extend in the direction substantially parallel to the longitudinal axis XX, while a gas flow path G is also substantially zigzag-shaped in the heat exchanger 3 comprising the gap 45 between the heat exchange elements 20 of the adjacent modular plates 4 .

According to the preferred embodiment shown, the gas flow path G extends at least partially between adjacent modular plates 4 in a second direction YY substantially perpendicular to the direction XX.

Thanks to the fact that the liquid flow path L and the gas-liquid path G im essentially cross each other, the heat exchange efficiency is advantageous increased compared to the efficiency that with heat exchangers according to the state the technology is achievable.

This effect is further increased by the fact that the section of the liquid flow path L 'also extends essentially in a zigzag shape in the hollow body 18 of each plate 4 and thus contributes to optimizing the heat exchange between the gas and the liquid.

Those disclosed in the foregoing description, claims and drawings Features can be used individually as well as in any combination for the realization of the invention in its various embodiments.

Claims (43)

1. Gas-liquid heat exchanger (3) with a plurality of modular heat exchanger plates (4) that can cause heat exchange between a gas and a heat transfer fluid, wherein each modular plate (4) comprises: a) an essentially plate-shaped hollow body ( 18 ) which is made in one piece from cast metal and has: 1. an inlet opening ( 13 ) and an outlet opening ( 15 ) for the liquid into and out of the hollow body ( 18 ), the inlet and outlet openings ( 13 , 15 ) at a proximal end ( 11 ) of the modular plate ( 4 ) are trained; 2. at least a first channel ( 22 ) which extends in a first direction between the proximal end ( 11 ) and a distal end ( 23 ) of the modular plate ( 4 ) for conveying the heat transfer fluid from the inlet opening ( 13 ) to the distal end ( 23 ) extends; 3. at least one second channel ( 24 ), which is arranged in series with the first channel ( 22 ) and in the first direction between the distal end ( 23 ) and the proximal end ( 11 ) of the modular plate ( 4 ) for conveying the heat transfer fluid extends from the distal end ( 23 ) to the outlet opening ( 15 ); b) at least provided with a plurality of heat exchange elements (20) portion (19) (18) protrude in a cantilevered fashion from the hollow body to the heat exchange surface between the gas and the heat transfer fluid to increase; c) at least one passage ( 21 ) for permitting a gas flow which is shaped to pass through the hollow body ( 18 ), at least a partial area of the section ( 19 ) being equipped with heat exchange elements ( 20 ), wherein the modular plates ( 4 ) are each mounted in packs so that they form a liquid flow path (L) and a gas flow path (G) in the heat exchanger ( 3 ) and the liquid flow paths (L) and the gas flow paths ( G) cross each other at least partially. 2. Heat exchanger according to claim 1, wherein the liquid flow path (L) substantially along a zigzag path between the inlet opening ( 13 ) and the outlet opening ( 15 ) of the heat transfer fluid in and out of the heat exchanger ( 3 ) and extends in each modular plate ( 4 ) at least partially in the first direction. 3. Heat exchanger according to claim 1, wherein the inlet and outlet openings ( 13 , 15 ) of the liquid in and out of the modular plates ( 4 ) in structurally independent inlet and outlet chambers ( 37 , 38 ) are formed, which are separated from one another in a liquid-tight manner are integrally formed in a collecting tube ( 10 ) which extends away from the proximal end ( 11 ) of the modular plate ( 4 ). 4. Heat exchanger according to claim 3, in which the modular plates ( 4 ) are reciprocally and fluid-tightly attached to the header pipe ( 10 ). 5. The heat exchanger according to claim 1, wherein the at least one first channel ( 22 ) is formed in the hollow body ( 18 ) near its one side wall ( 25 ). 6. The heat exchanger according to claim 5, wherein the at least one second channel ( 24 ) is formed in the hollow body ( 18 ) near the other side wall ( 27 ) thereof relative to the at least one first channel ( 22 ). 7. The heat exchanger according to claim 1, wherein the at least one first channel ( 22 ) is formed in the hollow body ( 18 ) near a first end face ( 43 ) of the hollow body. 8. The heat exchanger according to claim 7, wherein the at least one second channel ( 24 ) is formed in the hollow body ( 18 ) near an end face ( 42 ) opposite the at least one first channel ( 22 ). 9. The heat exchanger of claim 7 or 8, wherein the at least one and second channels ( 22 , 24 ) have a width that is substantially equal to the width of the at least one portion ( 19 ) that is associated with the heat exchange elements ( 20 ) of the modular plate ( 4 ) is provided. 10. The heat exchanger according to claim 1, wherein the hollow body ( 18 ) further has at least one intermediate channel ( 30 ) which is arranged in series with the at least one first channel ( 22 ) and the at least one second channel ( 24 ). 11. The heat exchanger according to claim 10, wherein the intermediate channel ( 30 ) extends substantially in a zigzag shape along the transverse central plane (π) of the modular plate ( 4 ). 12. The heat exchanger as claimed in claim 1, in which the at least one section ( 19 ) provided with a plurality of heat exchange elements ( 20 ) extends on opposite end faces ( 42 , 43 ) of the hollow body ( 18 ). 13. The heat exchanger as claimed in claim 1, in which the at least one section ( 19 ) provided with a plurality of heat exchange elements ( 20 ) is inclined at a certain angle (α) with respect to the transverse central plane (π) of the modular plate ( 4 ). 14. The heat exchanger according to claim 1, wherein the heat exchange elements ( 20 ) are staggered in a corresponding number of rows ( 20 a- 20 g) substantially parallel to a longitudinal axis (XX) of the modular plate ( 4 ). 15. Heat exchanger according to claim 14, wherein the rows ( 20 a 20 g) are staggered in a substantially perpendicular direction to the longitudinal axis (XX) of the modular plate ( 4 ). 16. The heat exchanger according to claim 14 or 15, wherein the modular plates ( 4 ) comprise a first ( 20 ') and a second group ( 20 ") rows ( 20 a - 20 g) of heat exchange elements ( 20 ), the first group ( 20 ') and the second group ( 20 ") rows ( 20 a- 20 g) are arranged on opposite sides of the longitudinal axis (XX) of the modular plate ( 4 ) and the rows ( 20 a- 20 c) of the first group ( 20 ') in the direction essentially parallel to the longitudinal axis (XX) with respect to the rows ( 20 d- 20 g) of the second group ( 20 ") are offset by a length (s) which is essentially half the pitch (p') the heat exchange elements ( 20 ) corresponds to the second group ( 20 "). 17. The heat exchanger according to claim 1, wherein the heat exchange elements ( 20 ) have a substantially frustoconical shape with an angle of inclination of approximately 2 ° to approximately 5 °. 18. The heat exchanger according to claim 1, wherein the gas flow path (G) forms a gap ( 45 ) of approximately constant thickness, which prevails between the heat exchange elements ( 29 ) of adjacent modular plates ( 4 ). 19. The heat exchanger of claim 18, wherein the gap ( 45 ) has a size of about 1 to about 3 mm. 20. The heat exchanger according to claim 1, wherein the passage ( 21 ) is formed to allow gas flow near a side wall ( 25 ) of the hollow body ( 18 ) of the modular plates ( 4 ). 21. The heat exchanger according to claim 1, wherein the gas flow path (G) an in essential zigzag path. 22. The heat exchanger of claim 1 or 21, wherein the gas flow path extends at least partially between adjacent modular plates ( 4 ) in a second direction (YY) that is substantially perpendicular to a longitudinal axis (XX) of the modular plate ( 4 ) runs. 23. A heat exchanger according to claim 1, in which a plurality of circumferential sealing means are arranged between adjacent modular plates ( 4 ). 24. Boiler ( 1 ) with a burner ( 2 ) and a heat exchanger ( 3 ) according to one of claims 1 to 23. 25. Boiler according to claim 24, in which the modular plates ( 4 ) of the heat exchanger are obtained by casting metal materials with different heat resistance and are mounted such that the modular plates ( 4 ) with greater heat resistance are positioned next to the burner ( 2 ) , 26. Boiler according to claim 24, in which the modular plates of the heat exchanger ( 3 ) are obtained by casting metals of different corrosion resistance and are mounted so that the modular plates of metals with lower corrosion resistance are positioned next to the burner. 27. Boiler according to claim 24, which has a collecting pipe ( 17 ) for collecting condensate downstream of the heat exchanger ( 3 ). 28. A modular heat exchanger plate ( 4 ) for effecting heat exchange between a gas and a heat transfer fluid, comprising: a) an essentially plate-shaped hollow body ( 18 ) which is made in one piece from cast metal and has: 1. an inlet opening ( 13 ) and an outlet opening ( 15 ) for the liquid in and out of the hollow body ( 18 ), the inlet and outlet openings ( 13 , 14 ) at a proximal end ( 11 ) of the modular plate ( 4 ) are trained; 2. at least a first channel ( 22 ) which extends in a first direction between the proximal end ( 11 ) and a distal end ( 23 ) of the modular plate ( 4 ) for conveying the heat transfer fluid from the inlet opening ( 13 ) to the distal end ( 23 ) extends; 3. at least one second channel ( 24 ), which is arranged in series with the first channel ( 22 ) and in the first direction between the distal end ( 23 ) and the proximal end ( 11 ) of the modular plate ( 4 ) for conveying the heat transfer fluid extends from the distal end ( 23 ) to the outlet opening ( 15 ); b) at least provided with a plurality of heat exchange elements (20) portion (19) (18) protrude in a cantilevered fashion from the hollow body to the heat exchange surface between the gas and the heat transfer fluid to increase; c) at least one passage ( 21 ) to allow a gas flow, which is shaped to pass through the hollow body ( 18 ), at least a partial area of the section ( 19 ) being equipped with heat exchange elements ( 20 ). 29. The modular plate of claim 28, wherein the inlet and outlet openings ( 13 , 15 ) of the liquid in and out of the modular plates ( 4 ) are defined in structurally independent inlet and outlet chambers ( 37 , 38 ) which are liquid-tightly separated from each other are formed in one piece in a collecting tube ( 10 ) which extends away from the proximal end ( 11 ) of the modular plate ( 4 ). 30. Modular plate according to claim 28, wherein the at least one first channel ( 22 ) in the hollow body ( 13 ) is arranged near the one side wall ( 25 ). 31. Modular plate according to claim 30, wherein the at least one second channel ( 24 ) is formed in the hollow body ( 18 ) near its other side wall ( 27 ) opposite the at least one first channel ( 22 ). 32. Modular plate according to claim 28, wherein the at least one first channel ( 22 ) is formed in the hollow body ( 18 ) near a first end face ( 43 ) of the hollow body. 33. Modular plate according to claim 32, wherein the at least one second channel is formed in the hollow body ( 18 ) near an end face ( 42 ) opposite the at least one channel ( 22 ). 34. Modular plate according to claim 32 or 33, wherein the at least one and second channels ( 22 , 24 ) have a width which is substantially equal to the width of the at least one section ( 19 ) which with the heat exchange elements ( 20 ) modular plate ( 4 ) is provided. 35. Modular plate according to claim 28, wherein the hollow body ( 18 ) further has at least one intermediate channel ( 30 ) which is arranged in series with the at least one first channel ( 22 ) and the at least one second channel ( 24 ). 36. Modular plate according to claim 35, wherein the intermediate channel ( 30 ) extends substantially in a zigzag shape along the transverse central plane (π) of the modular plate ( 4 ). 37. Modular plate according to claim 28, in which the at least one section ( 19 ) provided with a plurality of heat exchange elements ( 20 ) extends on opposite end faces ( 42 , 43 ) of the hollow body ( 18 ). 38. Modular plate according to claim 28, in which at least one section ( 19 ) provided with a plurality of heat exchange elements ( 20 ) is inclined at a certain angle (α) with respect to the transverse central plane (s) of the modular plate ( 4 ). 39. Modular plate according to claim 28, wherein the heat exchange elements ( 20 ) staggered in several rows ( 20 a- 20 g) are arranged substantially parallel to the longitudinal axis (XX) of the modular plate ( 4 ). 40. Modular plate according to claim 39, wherein the rows ( 20 a 20 g) are staggered in the direction substantially perpendicular to the longitudinal axis (XX) of the modular plate ( 4 ). 41. Modular plate according to claim 39 or 40, comprising a first group ( 20 ') and a second group ( 20 ") rows ( 20 a- 20 g) of heat exchange elements ( 20 ), wherein the first group ( 20 ') and second group ( 20 ") of rows ( 20 a - 20 g) is arranged on opposite sides of the longitudinal axis (XX) of the modular plate ( 4 ) and the rows ( 20 a - 20 c) of the first group ( 20 ') offset in Direction substantially parallel to the longitudinal axis (XX) with respect to the rows ( 20 d - 20 g) of the second group ( 20 ") are offset by a length (s) which is essentially half the pitch (p ') of the heat exchange elements ( 20 ) corresponds to the second group ( 20 "). 42. Modular plate according to claim 28, wherein the heat exchange elements ( 20 ) have a substantially frustoconical shape with an angle of inclination of approximately 2 ° to approximately 5 °. 43. Modular plates according to claim 28, wherein the passage ( 21 ) is designed to allow gas flow near a side wall ( 25 ) of the hollow body ( 18 ) of the modular plates ( 4 ).