EP0521298A2 - Heat exchange apparatus for dryer by refrigeration in compressed air plants and tubes/plates heat exchanger for this use - Google Patents

Abstract

A heat exchanger device for refrigeration dryers in compressed air systems is described. Such heat exchanger devices consist of an air / air heat exchanger (1) and a refrigerant / air heat exchanger (2). According to the invention, the air / air heat exchanger is made from a plate heat exchanger and the refrigerant / air heat exchanger is made from a combined tube / plate heat exchanger. The tube / plate heat exchanger has at least one unit that contains a meandering coil, on the two broad sides of which a plate is attached. <IMAGE>

Description

The invention relates to a heat exchanger device for refrigeration dryers in compressed air systems consisting of an air / air heat exchanger and a refrigerant / air heat exchanger and to a tube / plate heat exchanger which is particularly suitable as a refrigerant / air heat exchanger for such a device.

Compressed air systems of the type of interest here are used to generate, and to provide compressed air up to 25 bar. However, like the atmospheric air, this compressed air, at least in European areas, has a high moisture content corresponding to a relative air humidity of up to 80% and more. For many applications, e.g. in the food and paper industry or in the medical field, however, absolutely dry air is required. It is therefore known to pass the compressed air discharged from the compressor through a refrigeration dryer before it is put to its intended use, and to completely remove the moisture from it in this refrigeration dryer.

The air drying is usually carried out in such a way that the heated air coming from the compressor is first of all in an aftercooler to a temperature of, for example, 35-55 ° C. is cooled. The air is then passed through a heat exchanger device which has an air / air heat exchanger and a refrigerant-air heat exchanger.

The air / air heat exchanger serves the purpose, on the one hand, of the compressed air at approx. 35 - 55 ° C to e.g. 20 ° C to cool and on the other hand to heat the countercurrent, strongly cooled compressed air coming from a water separator to room temperature in order to avoid that a cold bridge is formed on the outside of the lines or apparatus leading to cold air.

In contrast, the refrigerant / air heat exchanger serves the purpose of cooling the compressed air coming from the air / air heat exchanger to approx. 20 ° C by means of a refrigerant, e.g. Freeze to cool to their dew point, which is usually 2 - 3 ° C. For this purpose, the refrigerant is liquefied in a known manner by means of a compressor and a condenser, then expanded through the refrigerant / air heat exchanger and thereby brought to a temperature of e.g. minus 2 ° C at its inlet and plus 4 ° C at its outlet, and then fed back to the compressor. The air thus cooled to its dew point is passed to a water separator after it has passed through the refrigerant / air heat exchanger, in which the moisture is completely removed from it, and is then passed through the air / air heat exchanger again by simultaneously cooling the air warm compressed air coming from the compressed air system is heated to about room temperature.

In the known heat exchanger devices of the type described, the two heat exchangers consist of nested pipes, preferably made of copper or brass, provided with fins, baffles or the like. Such heat exchangers fully meet the required requirements with regard to the required heat transfer, but also have two major shortcomings. A deficiency is that the manufacture of the heat exchanger is comparatively complex because of the large number of weld seams required. Above all, the fact that the heat exchangers have a large construction volume, require correspondingly large cladding and insulating materials and therefore also lead to a refrigeration dryer with considerable dimensions and considerable weight is disruptive. In addition, there is the problem that the flow baffles or the like result in high flow resistances and contamination by fluff or the like can occur quickly, which reduces cross-sectional areas result that reduce the efficiency.

The invention has for its object to design the heat exchanger device of the type mentioned in such a way that it has a comparatively small volume.

Another object of the invention is to design the heat exchanger device more cost-effectively.

Another object of the invention is to design the heat exchanger device so that the risk of contamination is low.

Finally, it is a further object of the invention to provide a tube / plate heat exchanger which is particularly suitable for the heat exchanger device of the type mentioned at the outset and, in particular, as a refrigerant / air heat exchanger.

In the heat exchanger device according to the invention, the air / air heat exchanger consists of a plate heat exchanger and the refrigerant / air heat exchanger consists of a combined tube / plate heat exchanger.

A tube / plate heat exchanger which is particularly suitable for the purposes of the invention has at least one unit which contains a meandering coil which has a plate attached to each of its two broad sides.

The invention has the advantage that a heat exchanger device has been created in a compact design, which makes it possible to reduce the construction volume required for the entire refrigeration dryer to about a third of the previously required volume. Since the heat exchangers of the heat exchanger device according to the invention are also preferably made of aluminum, the invention also leads to a considerable reduction in weight. Finally, the heat exchanger device according to the invention can be produced inexpensively, as a result of which the overall cost of the refrigeration dryer can be appreciably reduced. The tube / plate heat exchanger according to the invention is also very compact and, on the one hand, enables a small construction volume. On the other hand, it can be formed on the process air side so large that the The risk of serious contamination, in particular that which leads to a noticeable reduction in cross-section, is low. Finally, the heat exchanger has closed pipes on the refrigerant side, so that, in contrast to plate-type heat exchangers, it has a high compressive strength.

Fig. 1

eine schematische Seitenansicht einer ersten Ausführungsform der erfindungsgemäßen Wärmetauscher-Vorrichtung;

Fig. 2

die Draufsicht auf die Wärmetauscher-Vorrichtung nach Fig. 1;

Fig. 3

eine Ansicht auf die Wärmetauscher-Vorrichtung in Richtung eines Pfeils X nach Fig. 1, wobei ein mit einem Einlaßflansch versehener Sammelkasten längs der Linie III-III der Fig. 2 geschnitten dargestellt ist;

Fig. 4

einen Schnitt längs der Linie IV-IV der Fig. 3;

Fig. 5

eine Seitenansicht eines Wärmetauscherblocks eines Luft/Luft-Wärmetauschers der Wärmetauscher-Vorrichtung nach Fig. 1 und 2;

Fig. 6

die Draufsicht auf eine Passage für das eine Wärmeaustauschmedium des Wärmetauscherblocks längs der Schnittlinie VI-VI der Fig. 5;

Fig. 7

die Draufsicht auf eine Passage für das andere Wärmeaustauschmedium des Wärmetauscherblocks längs der Schnittlinie VII-VII der Fig. 5;

Fig. 8

eine Seitenansicht eines Wärmetauscherblocks eines Kältemittel/Luft-Wärmetauschers der Wärmetauscher-Vorrichtung nach Fig. 1;

Fig. 9

die Draufsicht auf den Wärmetauscherblock längs der Schnittlinie IX-IX der Fig. 8;

Fig. 10

eine Ansicht des Wärmetauscherblocks nach Fig. 8 in Richtung eines Pfeils Y;

Fig. 11

schematisch eine Seitenansicht einer zweiten Ausführungsform der erfindungsgemäßen Wärmetauscher-Vorrichtung;

Fig. 12

eine Draufsicht auf die Wärmetauscher-Vorrichtung nach Fig. 10 mit der in Richtung eines Pfeils Z dargestellten Ansicht einer Einzelheit C;

Fig. 13

eine Ansicht der Wärmetauscher-Vorrichtung nach Fig. 11 in Richtung eines Pfeils V und in vergrößertem Maßstab;

Fig. 14

einen Schnitt längs der Linie XIV-XIV der Fig. 12 in vergrößertem Maßstab;

Fig. 15

eine Seitenansicht eines Wärmetauscherblocks eines kombinierten Luft/Luft- und Kältemittel/Luft-Wärmetauschers der Wärmetauscher-Vorrichtung nach Fig. 11; und

Fig. 16

die Draufsicht auf den Wärmetauscherblock längs der Schnittlinie XVI-XVI der Fig. 15;

Fig. 17

eine Ansicht des Wärmetauscherblocks nach Fig. 15 in Richtung eines Pfeils W;

Fig. 18

die Draufsicht auf den Wärmetauscherblock längs der Schnittlinie XVIII-XVIII der Fig. 15;

Fig. 19

einen Querschnitt durch eine Einheit eines erfindungsgemäßen Kältemittel/Luft-Wärmetauschers gemäß einer zweiten Ausführungsform;

Fig. 20

eine vergrößerte Einzelheit X der Einheit nach Fig. 19;

Fig. 21

eine perspektivische Darstellung eines Wärmetauscherblocks, der aus einer Vielzahl von Einheiten nach Fig. 22 zusammengesetzt ist;

Fig. 22

eine Vielzahl von hintereinander angeordneten Einheiten nach Fig. 19 mit einer durchgehenden Rohrschlange in perspektivischer Darstellung; und

Fig. 23

eine der Fig. 21 entsprechende Darstellung einer weiteren Ausführungsform eines erfindungsgemäßen Wärmetauscherblocks.

The invention is explained in more detail below in connection with the accompanying drawing using exemplary embodiments. Show it:

Fig. 1

is a schematic side view of a first embodiment of the heat exchanger device according to the invention;

Fig. 2

the top view of the heat exchanger device of FIG. 1;

Fig. 3

a view of the heat exchanger device in the direction of an arrow X of Figure 1, wherein a collecting box provided with an inlet flange is shown cut along the line III-III of Figure 2;

Fig. 4

a section along the line IV-IV of Fig. 3;

Fig. 5

a side view of a heat exchanger block of an air / air heat exchanger of the heat exchanger device according to FIGS. 1 and 2;

Fig. 6

the top view of a passage for the one heat exchange medium of the heat exchanger block along the section line VI-VI of Fig. 5;

Fig. 7

the top view of a passage for the other heat exchange medium of the heat exchanger block along the section line VII-VII of Fig. 5;

Fig. 8

a side view of a heat exchanger block of a refrigerant / air heat exchanger of the heat exchanger device of FIG. 1;

Fig. 9

the top view of the heat exchanger block along the section line IX-IX of Fig. 8;

Fig. 10

a view of the heat exchanger block of Figure 8 in the direction of an arrow Y;

Fig. 11

schematically shows a side view of a second embodiment of the heat exchanger device according to the invention;

Fig. 12

a plan view of the heat exchanger device of Figure 10 with the view shown in the direction of an arrow Z of a detail C.

Fig. 13

a view of the heat exchanger device of Figure 11 in the direction of an arrow V and on an enlarged scale.

Fig. 14

a section along the line XIV-XIV of Figure 12 on an enlarged scale.

Fig. 15

a side view of a heat exchanger block of a combined air / air and refrigerant / air heat exchanger of the heat exchanger device of FIG. 11; and

Fig. 16

the top view of the heat exchanger block along the section line XVI-XVI of Fig. 15;

Fig. 17

a view of the heat exchanger block of Figure 15 in the direction of an arrow W.

Fig. 18

the top view of the heat exchanger block along the section line XVIII-XVIII of Fig. 15;

Fig. 19

a cross section through a unit of a refrigerant / air heat exchanger according to the invention according to a second embodiment;

Fig. 20

an enlarged detail X of the unit of FIG. 19;

Fig. 21

a perspective view of a heat exchanger block, which is composed of a plurality of units of FIG. 22;

Fig. 22

a plurality of units arranged one behind the other according to FIG 19 with a continuous pipe coil in a perspective view. and

Fig. 23

a representation corresponding to FIG. 21 of a further embodiment of a heat exchanger block according to the invention.

1 and 2 contains an air / air heat exchanger 1 and a refrigerant / air heat exchanger 2. Both heat exchangers 1 and 2 are arranged one above the other according to FIG. 1, the refrigerant / air heat exchanger 2 under the Air / air heat exchanger 1 is located, although it could also be the other way around.

The air / air heat exchanger 1 (Fig. 1) consists of a plate heat exchanger and contains a heat exchanger block 3 (Fig. 5-7) with passages 4 and 5 made in plate construction, each in the direction of the arrows, i.e. predominantly in counterflow, through which air flows. 6 and 7, the air enters laterally at one end of the passages 4 and 5 and exits again in the longitudinal direction at the opposite end. The passages 4 and 5 are also arranged alternately one above the other in accordance with FIGS. 4 and 5.

Each passage 4 is of two parallel to the longitudinal direction of the heat exchanger block 3, to the left in Fig. 6 end of the heat exchanger block 3 strips 6 and 7 with a substantially square or rectangular cross-section and two arranged above or below the same over the entire length and Width of the heat exchanger block 3 extending plates 8 is formed. At the left end in FIGS. 5 and 6, the passages 4 are open. In contrast, the passages 4 are closed at the right end in FIGS. 5 and 6 by strips 9 extending across the width of the heat exchanger block 3, while at the same time the strips 6 are shorter than the strips 7, so that the passages 4 according to FIG right end, but open to the side and the air can flow in from the side in the direction of the arrow. In the passages 4, usual slats 10 are expediently inserted, which are only partially shown in FIG. 5 and whose passages are deflected along a line 11 by 90 ° according to FIG. 6.

In contrast, each passage 5 according to FIGS. 5 and 7 is formed by two strips 14 and 15, which are parallel to the longitudinal direction of the heat exchanger block 3 and border on the right end of the heat exchanger block 3 in FIG. 7, with a substantially square or rectangular cross section and two further plates 8, arranged above or below the same, extending over the entire length and width of the heat exchanger block 3. At the right end in FIGS. 5 and 7, the passages 5 are open. In contrast, the passages 5 at the left end in FIGS. 5 and 7 are closed off by strips 16 extending over the width of the heat exchanger block 3, while at the same time the strips 14 are shorter than the strips 15, so that the passages 5 according to FIG. 7 are not to the left End, but to the side, expediently open to the same side as the passages 4 and the air can flow in from the side in the direction of the arrows. In the passages 5 lamellae 17 are expediently inserted, which are only partially visible in FIG. 5 and whose passages are deflected along a line 18 by 90 ° according to FIG. 7.

The strips 6, 7, 9 and 16, the plates 8 arranged between them and the plates 10 and 17 arranged between two plates 8 are stacked one on top of the other, as is known per se from plate-type heat exchangers, and arranged such that alternately a passage 4 or 5 is formed and the heat exchanger block 3 is closed at the top and bottom by a plate 8 each. The plate 8 and possibly also the strips 6, 7, 9 and 16 preferably consist of aluminum clad with a solder and are first stacked in a manner known per se and then soldered to one another in an air or vacuum oven or also in a flux bath.

The strips 6 and 14, the strips 7 and 15 and the strips 9 and 16 are expediently of identical design, so that, according to FIGS. 5 and 7, a symmetrical and particularly inexpensive production of the heat exchanger block 3 results. The number of passages 4 and 5 depends on the required output of the heat exchanger block 3.

The refrigerant / air heat exchanger 2 (FIG. 1) consists of a combined tube / plate heat exchanger and contains a heat exchanger block 20 (FIGS. 8 to 10) with passages 21 for a refrigerant and passages 22 for the compressed air, the passages 21 and 22 each in the direction of the arrows drawn in FIG. 9, ie predominantly in direct current, through which the refrigerant or compressed air flows.

The passages 21 for the refrigerant consist of tubes with a round or preferably rectangular or square cross section, which are arranged between two plates 23 extending over the length and width of the heat exchanger block 20. Each passage 21 extends in a serpentine or meandering fashion and has a plurality of straight sections 24 which, in the exemplary embodiment, are arranged parallel to one another and perpendicular to the longitudinal axis and at a close distance. Each two adjacent straight sections 24 are connected in accordance with FIG. 9 by sections 25 bent by 180 ° in such a way that there is an uninterrupted flow path from an inlet 26 to an outlet 27. 8 and 10 in particular, each passage 22 for the compressed air is delimited from two spacers 28, for example in the form of strips, which extend at the side edges of two parallel plates 23 and keep them at a distance, running in the longitudinal direction of the heat exchanger block 20. Slats 29 of conventional construction are arranged between the two plates 23. The passages 22 are therefore open in FIGS. 8 and 9 at the right and left ends, respectively. The arrangement is such that the passages 21 and 22 alternate in the heat exchanger block 20, that is to say that the tubes (passages 21) are covered on both sides with plates 23 and these are kept at a distance by the spacers 28 to form the passages 21. According to this scheme, three passages 21 and four passages 22 are formed in FIGS. 8 to 10, wherein in each case one passage 21 can form a unit with the two adjoining plates 23. In addition, between each two plates 23, between which the tubes forming the passages 21 are arranged, parallel to the straight sections 24, for example also strip-shaped closure elements 30 and at the upper and lower ends, an end plate 31 can be provided, the closure elements 30 primarily serve to protect the space between the individual pipe sections from contamination.

The different parts of the heat exchanger block 20, like those of the heat exchanger block 3, preferably consist of aluminum, in particular aluminum clad with a solder, and are first stacked in a manner known per se and then soldered to one another.

1 to 3, the heat exchanger blocks 3 and 20 are arranged one above the other and firmly connected to one another, for example soldered. Here, the passages 5, where the air enters them (FIG. 7), are connected in a liquid-tight manner to a collecting tank 33 which is arranged laterally and extends over the height of the heat exchanger block 3 and is provided with an inlet flange 34 having an inlet opening. In contrast, the passages are 5 at their right ends, which are open in FIGS. 1 and 2, through a collecting or deflecting box 35, which extends over the width and height of both the heat exchanger block 3 and the heat exchanger block 20, with the likewise open right ends of the passages 22 (FIG. 10) of the heat exchanger block 20 connected liquid-tight. Furthermore, the passages 4 of the heat exchanger block 3, where the air enters them (FIG. 6), are connected in a liquid-tight manner to a collecting tank 36 which extends over the height of the heat exchanger block 3 and is provided with an inlet flange 37 which has an inlet opening. In contrast, the passages 4 open at their left end, which is open in FIGS. 1 and 2, in a liquid-tight manner into a further collecting box 38, which extends over the height and width of the heat exchanger block 3 and is provided with an outlet flange 39 having an outlet opening. This is covered by the inlet flange 34 in FIG. 1 and is therefore only visible in FIG. 2. Finally, the left ends of the passages 22, which are open in FIG. 9, are provided with a liquid-tight header box 40 which extends over the width and height of the heat exchanger block 20 and which, according to FIG. 2, has an extension 41 which projects to the side and which has an outlet opening Connection flange 42 is provided, wherein the flow direction is parallel to that of the inlet flange 34, while its inlet opening is opposite to the outlet opening of the outlet flange 42.

The entrances and exits 26, 27 of the passages 21, which are shown only schematically in FIGS. 2 and 10, are each combined according to FIGS. 3 and 4 by a tubular construction. Since a total of three passages 21 are provided in accordance with FIGS. 8 to 10, the three resulting outlets 27 are guided in the manner shown in FIGS. 3 and 4 through curved intermediate sections 43 to a flange 44 with a common outlet opening, which is via a curved tube 45 is provided liquid-tight with a connecting nipple 46. The inputs 26 are correspondingly connected to a connecting nipple 47 (FIG. 1), which is not visible in FIG. 3, because this arrangement comprises parts corresponding to parts 43 to 46.

The heat exchanger device described, consisting of two firmly connected heat exchangers 1 and 2, forms a compact, space-saving unit which, as a whole, can above all be assigned to a refrigeration dryer with which conventional compressed air systems are equipped, as will be explained briefly below. This has the particular advantage that the two heat exchangers 1 and 2 are essentially the same Have width and length and can be combined into a common block.

Compressed air is supplied from a compressor, which is preferably provided with an aftercooler. is at a temperature of approx. 35 - 55 ° C. This compressed air is first fed to the collecting box 33 by means of the inlet flange 34 and flows from there in the direction of an arrow line 49 (FIGS. 2 and 7) through the passages 5 of the air / air heat exchanger 1 into the collecting and deflecting box 35. From there the compressed air into the refrigerant / air heat exchanger 2 (FIG. 1) and then flows in the opposite direction through its passages 22 (FIG. 10 and arrow line 50 in FIG. 9). At the same time, the refrigerant is guided through the passages 21 in the direction of the arrows shown in FIG. 9 and thereby relaxed, due to the long running time caused by the straight and curved pipe sections 24, 25 (FIG. 9) in the refrigerant / air heat exchanger 2 Despite its comparatively short overall length, a high degree of effectiveness with regard to the desired cooling of the compressed air is achieved. Otherwise, the refrigerant is conducted in a manner known per se in a refrigerant circuit, it being fed to the connection nipple 47 and discharged at the connection nipple 46 (FIGS. 1, 3 and 5).

The compressed air cooled to the dew point (e.g. approx. 2-3 ° C) flows after the passage through the passages 22 into the collecting box 40 (FIG. 1), is deflected laterally in this and passes over its lateral extension 41 (FIG. 2 ) and the outlet flange 42 again. The compressed air is then fed to a water separator 51, as is shown schematically in FIG. 2. The completely dried compressed air emerging from this is finally fed back to the air / air heat exchanger 1 via the inlet flange 37 (FIG. 2) and the collecting tank 36, so that they passages 4 in the direction of an arrow line 52 in FIGS. 2 and 6 can happen. In this case, the compressed air in interaction with the warm compressed air passing through the passages 5 is warmed up to approximately room temperature before it reaches the collecting tank 38 (FIG. 2) and is supplied to the tap for the compressed air via the outlet flange 39. Depending on the required output of the two heat exchangers 1 and 2, the number of their passages 4 and 5 or 21 and 22 can in principle be increased as desired by stacking a corresponding number of further plates or tubes without the dimensions increasing in height and change the width of the heat exchanger device.

An even more compact and less space-consuming heat exchanger device, which is particularly suitable for smaller outputs, results from FIGS. 11 to 17. It contains an air / air heat exchanger 56 and a refrigerant / air heat exchanger 57. Both heat exchangers In contrast to FIGS. 1 to 10, 56, 57 are not arranged one above the other, but side by side and connected to one another to form an integral structural unit. For this purpose, both heat exchangers 56 and 57 are produced from a coherent heat exchanger block 58, which has a section 59 responsible for the air / air heat exchange in its right-hand part in FIGS. 15, 16 and 18 and its section in FIGS. 15, 16 and 18 left part has a section 60 responsible for the heat exchange refrigerant / air. Both sections 59, 60 are formed by plates 61, which extend over the entire width and length of the heat exchanger block 58. Part of the plates 61 is on the one hand by strips 62 running perpendicular to the longitudinal direction, arranged at the right end of the heat exchanger block 58 in FIG. 15, and on the other hand by strips extending in the longitudinal direction and extending to the left end in FIGS Side edges of the plates 61 arranged strips 63 and 64 kept at a distance. This creates passages 65 between the plates 61, which are open at the left end of the heat exchanger block 58 in FIG. 18. At the right end in FIG. 18, the lower strips 64 are somewhat shorter, so that a space 66 is created between their right ends and the strips 62, through which air can enter laterally in the direction of the arrow shown. In addition, the usual slats 67 (FIGS. 15 and 17) are arranged in the passages 65, which are designed according to FIG. 18 in such a way that the air entering laterally is deflected along a line 68 (FIG. 18).

The other part of the plates 61 is, according to FIGS. 15 and 16, in the part forming the section 59 by strips 69 which run parallel to the longitudinal direction, are arranged on the side edges of the plates 61 and extend to the right end of the heat exchanger block 58 in FIGS. 15 and 16 and 70 and a transversely extending, at the left end of the section 59 terminating strip 71 terminated. This creates a further passage 72 between two plates 61, which is open at the right end of the heat exchanger block 58 in FIG. 16. On the side of the end bar 71, the upper bar 69 in FIG. 16 is somewhat shorter, so that an intermediate space 73 is formed between the two, which is in comparison to the intermediate space 66 on the opposite side of the heat exchanger block 58, so that air enters laterally and in Direction of the drawn line (Fig. 16) can be deflected. Analogously to FIG. 18, the deflection is preferably also corresponding trained slats 74 causes.

In section 60, on the other hand, the same plates 61 are kept at a distance by a serpentine or meandering passage 76 which has straight and curved sections 77, 78 and is constructed and arranged essentially in the same way as passages 21 according to FIGS. 8 to 10 . The passage 76 extends from the end bar 71 to an end bar 79 arranged at the left end of the heat exchanger block 58 in FIG. 17.

Otherwise, the arrangement is such that the passages 72 and 76 are arranged in a central part of the heat exchanger block 58, to each of which a passage 65 (FIG. 15) is connected upwards and downwards.

According to FIGS. 11 to 14 and analogously to FIGS. 1 to 4, an inlet 81 and an outlet 82 (FIG. 16) of the passage 76 are each provided with a connecting nipple 84, 85 via curved pipe sections 83, of which only the one in FIG. 13 Connection nipple 85 is visible. Furthermore, the right ends of the passages 65 in FIGS. 15, 16 and 18 are connected in a liquid-tight manner to a collecting box 86 and an inlet flange or inlet nipple 87 having an inlet opening, while the left ends of the passages 65 in FIGS. 15, 16 and 18 are connected to a collecting box 88 are connected in a liquid-tight manner, which, like the collecting box 40 according to FIGS. 1 and 2, has a lateral extension 89 which is provided with a connecting flange 91 having an outlet opening 90. Finally, the side opening of the passage 72 (Fig. 16) is fluid-tightly connected to a header 92 and an inlet flange or inlet nipple 93 having an inlet opening, while the right end of the passage 72 in Figs. 11 and 12 is connected to a header 94 and an outlet opening having outlet flange or outlet nipple 95 is connected liquid-tight.

Analogous to the embodiment according to FIGS. 1 to 10, the compressed air coming from the compressed air system and heated to, for example, about 35-55 ° C. is fed to the collecting box 86 via the inlet flange 87, so that it passes the passages 65 in the direction of an arrow line 96 (FIG. 18) flows through. The compressed air is first brought to a temperature of in the heat exchanger 56 by the cold compressed air coming from a water separator, not shown, in countercurrent via the inlet flange 93 or the collecting tank 92 cooled down to approx. 20 ° C. On its way through the passages 65, the compressed air is then gradually cooled to the dew point in the heat exchanger 57, since it interacts with the refrigerant that flows through the passage 76 in the direction of the arrows (FIG. 16). The compressed air is then fed via the collecting box 88 and the outlet flange 91 to the water separator and from there to the inlet flange 93, so that it is again heated to approximately room temperature at the outlet nipple 95, which serves as a tap for the compressed air.

As in the embodiment of FIGS. 1 to 10, the performance of the heat exchanger device can be changed in that the number of passages 65, 72 and 76 is changed accordingly while the length and width of the heat exchanger block 58 remain the same.

The refrigerant / air heat exchanger described with reference to FIGS. 8 to 10 and 15 to 18 can also be put together by a plurality of the units 140 shown in FIGS. 19 and 20, which contains a meandering coiled tube 141 designed according to FIG. 9 , on the two broad sides of which a plate 142 or 143 is attached. The pipe coil 141 can be e.g. either by soldering or by gluing to the plates 142, 143, as indicated in FIG. 20 by the reference symbol.

The entire heat exchanger block expediently consists of a multiplicity of units 140 (FIG. 21) stacked one above the other, which are kept at a distance by spacers 145, for example strips. 22, all coils 141 are formed from a single, continuous tube. In order to simplify the manufacture of the heat exchanger block, a plurality of units 140 coupled to one another are first produced in accordance with FIG. 22, the pipe coils 141 of which are connected to one another by an S-shaped or Z-shaped pipe section 146. 22, the units 140 can be arranged one behind the other, but also next to one another, in a star shape, triangular shape, circular shape or the like. The individual units 140 are then placed one on top of the other, the tube sections 146 simply being folded over according to FIG. 21 and therefore coming to lie outside the front or rear end of the actual heat exchanger block.

In contrast to FIGS. 8 to 10, the refrigerant does not flow through the various units 140 in parallel, but in succession. The connections for the compressed air and the refrigerant can be made analogously to FIGS. 1 to 18.

The cavities located between the plates 142, 143 and receiving the pipe coil 141 are expediently closed analogously to FIGS. 8 to 10 by strip-shaped end elements 149, which may consist of U-profiles, but preferably consist of folds attached to the plates 142, 143, as in particular Fig. 19 shows.

As in the embodiment according to FIGS. 8 to 10, the straight sections of the pipe coil 141 preferably run perpendicular to the strips 145, so that the compressed air or refrigerant flows are also predominantly perpendicular to one another.

The invention is not limited to the exemplary embodiments described, which can be modified in many ways. As an alternative to FIGS. 8 to 10, 15 to 18 and 19 to 21, it would be possible, for example, to use the spacers 28 and the respectively adjacent plates 23 or the spacers 145 and the two adjacent plates 142 and 143 as e.g. to form folded pipes 150 (FIG. 23) with a flat oval or rectangular cross section and to fix the pipe coil 21 or 141 in each case between two such pipes, the axes of these pipes being expediently arranged perpendicular to the straight sections of the pipe coil.

Furthermore, it would be possible to assemble the passages 21, 76 and 141 not from a continuous tube, but from a plurality of tubes running in parallel or from tube sections produced in a conventional plate construction, the sections corresponding to the straight sections being transversely to the longitudinal direction of the heat exchanger block 20 and 58, respectively extending strips and the sections corresponding to the curved sections are also formed by straight but longitudinal sections, for example by the mentioned strips alternately ending in front of one or the other longitudinal edge of the respective heat exchanger block and thereby freeing the refrigerant by 180 ° deflecting deflecting sections.

It is also possible to move the connections shown (inlet and outlet flanges and nipples) to other locations, should this prove to be more expedient, whereby the flow directions for the air and the refrigerant indicated by arrows are only examples. It would also be possible to produce the heat exchangers described from materials other than aluminum and / or to use them for purposes other than the purpose described. In particular, for example, the refrigerant / air heat exchangers described are also excellently suitable for tumble dryers which have become known in recent times and in which the warm and moist air coming from the tumble dryer is initially in a refrigerant / air heat exchanger which is effective as an evaporator for a refrigerant is cooled to separate the water and is then preheated again. While conventional refrigerant / air heat exchangers are subject to high levels of contamination, the heat exchangers according to the invention can easily be designed such that, for example, the passages 22 according to FIGS. 8 to 10 of inwardly projecting projections, edges or the like, in particular also from the others usual slats or the like, are completely free. In this case, because there are only large, smooth surfaces on the air side, the risk of contamination, in particular that which leads to noticeable cross-sectional reductions over time, would be comparatively low. Nevertheless, such a heat exchanger could be designed with high pressure resistance on the refrigerant side and be manufactured with small dimensions overall. Furthermore, the individual elements of the heat exchangers described can be used in combinations other than those shown. Instead of the spacers 28 and 145, grooved plates or the like could be provided, which extend over the entire height and depth of the heat exchanger blocks 20 and 140 and accommodate the plates 23, 142 and 143 with their grooves. These grooved plates could also have holes through which the pipe sections 146 or the ends 147 are guided to the outside. Finally, the flows of the refrigerant and the air can also flow differently than in cross flow, in particular also in cocurrent or countercurrent or in any other direction depending on the individual case, for which purpose the strips, pipe coils or the like merely have a different orientation in the need to receive the respective heat exchanger block 20 or 140. It is readily apparent that the strip-shaped spacers 145 in FIG. 21 could also be arranged on the free sides of the plates 142 and 143 there, ie parallel to the straight sections of the pipe coil 141.

Claims (18)

Heat exchanger device for refrigeration dryers in compressed air systems, consisting of an air / air heat exchanger and a refrigerant / air heat exchanger, characterized in that the air / air heat exchanger (1, 56) consists of a plate heat exchanger and the refrigerant / air heat exchanger ( 2, 57) consists of a combined tube / plate heat exchanger. Heat exchanger device according to claim 1, characterized in that the two heat exchangers (1, 2) are arranged one above the other and are connected to one another to form a structural unit. Heat exchanger device according to Claim 1, characterized in that the two heat exchangers (56, 57) are arranged next to one another and are connected to one another to form a structural unit. Heat exchanger device according to one of Claims 1 to 3, characterized in that the refrigerant / air heat exchanger (2, 57) consists of plates (23, 61) stacked one above the other and strips (28, 30 or 64, 71, spacing them apart) 79) and between the plates at least one passage (22, 65) provided with fins (29, 67) and a passage (20, 76) consisting of at least one pipe are formed. Heat exchanger device according to claim 4, characterized in that the pipeline consists of a continuous, meandering pipe with straight sections (24, 77) arranged parallel to one another and connecting sections (25, 78) deflecting by 180 °. Heat exchanger device according to claim 5, characterized in that the straight sections (24, 77) are arranged perpendicular to the direction of flow in the passages (22, 65) having the fins (29, 67). Heat exchanger device according to one of Claims 2 and 4 to 6, characterized in that the air / air heat exchanger (1) has two different types of passages (4, 5), one of which passes through a collecting and deflecting box (35 ) are connected to the passages (22) of the refrigerant / air heat exchanger (2) having the fins (29). Heat exchanger device according to one of claims 3 to 6, characterized in that the two heat exchangers (56, 57) have a common heat exchanger block (58). Heat exchanger device according to Claim 8, characterized in that the heat exchanger block (58) is formed from plates (61) stacked one above the other and strips (62, 63, 64, 69, 70, 71, 79) which keep them at a distance, with at least two Plates (61) are a first passage (72) forming a component of the air / air heat exchanger (56) and in the longitudinal direction next to a second passage (76) forming a component of the refrigerant / air heat exchanger (57). Heat exchanger device according to Claim 9, characterized in that at least one of these plates (61) interacts with a third passage (65) formed by at least one further plate (61) and extending essentially over the entire length of the heat exchanger block (58) stands. Heat exchanger device according to one of claims 1 to 10, characterized in that both heat exchangers (1, 2 and 56, 57) are made of aluminum. Pipe / plate heat exchanger, in particular for a heat exchanger device according to one or more of claims 1 to 11, characterized in that it consists of a combined pipe / plate heat exchanger and has at least one unit which has a meandering coil (21, 141) contains, on the two broad sides of which a plate (23 or 142, 143) is attached. Heat exchanger according to claim 12, characterized in that it contains a plurality of units (140) stacked one above the other to form a block, which are spaced apart by spacers (28, 145). Heat exchanger according to claim 13, characterized in that the tube coils (141) of all units are formed from a continuous tube which is folded over at the ends of the block. Heat exchanger according to one of claims 12 to 14, characterized in that the pipe coil (21) consists of straight pipe sections (24) which are laid essentially parallel to one another and sections which connect them and deflect by 180 ° (25). Heat exchanger according to one of claims 13 to 15, characterized in that the spacers (28, 145) are rectilinear and are arranged parallel to one another. Heat exchanger according to one of Claims 12 to 16, characterized in that the lateral edges which run parallel to the straight pipe sections of each pipe coil (21, 141) and are formed by the two associated plates (23 or 142, 143) are closed by end elements (30, 149) or bevels. Heat exchanger according to claim 12, characterized in that it consists of a plurality of tubes (150) with a flat oval or rectangular cross section stacked one above the other to form a block, between which the tube coils (21, 141) are arranged.

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