Heat exchanger

Abstract

Heat exchanger (120) designed as an evaporator for a compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the heat exchanger (120) has the following features: a heat transfer block (222) with compressed air passages (323) shaped to guide compressed air through the heat transfer block (222), with refrigerant passages (325) shaped to guide a flammable refrigerant through the heat transfer block (222), and with separating passages (327) arranged between the refrigerant passages (325) and the compressed air passages (323), wherein the heat transfer block (222) is constructed from separating plates (224) between the passages (323, 325, 327), fins (226) in the passages (323, 325, 327), and strips (228) as side walls of the passages (323, 325, 327), and is shaped to allow heat transfer between compressed air guided through the compressed air passages (323) and through the to effect refrigerant passages (325) guided refrigerant; and an outer section arranged outside the heat transfer block (222), the outer section comprising first means (430) for distributing, collecting and / or diverting the compressed air from and into compressed air passages (323) and second means (440) for distributing, collecting and / or diverting the refrigerant from and into refrigerant passages (325), the heat exchanger (120) being formed as a double wall in boundary regions (650) where first means (430) and refrigerant passages (325) or second means (440) and compressed air passages (323) are adjacent to each other, with at least one channel (660) being arranged between double wall elements (228, 628, 980) which leads to a safety area separate from the first means (430) and the compressed air passages (323).

Description

[0001] The present invention relates to a heat exchanger, a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer with such a heat exchanger, and a compressed air refrigeration dryer with such a compression refrigeration machine.

[0002] For example, so-called safety refrigerants can typically be used as refrigerants in compression refrigeration machines. Due to their chemical composition, these are non-flammable and non-toxic. However, particularly within the framework of EU Regulation 2024 / 573 on fluorinated greenhouse gases and a potential revision of the REACH Regulation, fluorinated refrigerants, such as the components of refrigerant R-513A, may be increasingly restricted or even banned by legislation. This could necessitate the use of natural refrigerants like R290 (propane). R290 is a flammable refrigerant. In known heat exchangers, etc.For example, in the case of heat exchangers for compressed air refrigeration dryers, the rare occurrence of refrigerant leakage into the compressed air is not considered, as the non-flammable and non-toxic refrigerants used so far pose no risk. However, this scenario of heat exchanger failure should be taken into account when using flammable refrigerants.

[0003] Against this background, the present invention provides an improved heat exchanger, an improved compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer, and an improved compressed air refrigeration dryer according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

[0004] According to certain embodiments, a safe heat exchanger or safety heat exchanger for flammable refrigerants can be provided. To prevent the transfer of flammable refrigerant into the compressed air or vice versa in the event of a leak, refrigerant passages or, more generally, refrigerant-carrying parts of the heat exchanger can be designed to allow leakage to the atmosphere or another safe area. This prevents, in particular, the formation of a flammable mixture in the compressed air network. It also reliably prevents compressed air from entering the refrigeration circuit.

[0005] A heat exchanger is presented which is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer, wherein the heat exchanger has the following features: a heat transfer block with compressed air passages shaped to guide compressed air through the heat transfer block, with refrigerant passages shaped to guide a flammable refrigerant through the heat transfer block, and with separating passages arranged between the refrigerant passages and the compressed air passages, wherein the heat transfer block is constructed of separating plates between the passages, fins in the passages, and strips as side walls of the passages, and is shaped to effect heat transfer between compressed air guided through the compressed air passages and refrigerant guided through the refrigerant passages; and an outer section arranged outside the heat transfer block, wherein the outer section has first means for distributing, collecting and / or diverting the compressed air from and into compressed air passages and second means for distributing, collecting and / or diverting the refrigerant from and into refrigerant passages, wherein the heat exchanger is formed as a double wall in boundary regions where first means and refrigerant passages or second means and compressed air passages are adjacent to each other, wherein at least one channel is arranged between double wall elements, leading to a safety area separate from the first means and the compressed air passages.

[0006] The heat exchanger can also be referred to as a heat exchanger device. The compressed air treatment can include drying by cooling, thus combining drying and cooling. The heat transfer block can be made of aluminum, for example, with the baffles, strips, and optionally the fins also being made of aluminum. The heat transfer block can be constructed by brazing and, additionally or alternatively, welding. In this case, the baffles, strips, and optionally the fins can be brazed and, additionally or alternatively, welded together. The baffles can be designed as empty passages, allowing heat flow from the compressed air to the refrigerant and otherwise vented to the atmosphere. Alternatively, the baffles can be filled with a medium and, optionally, through which the medium flows.The medium can be, for example, a phase change material (PCM), another latent heat storage medium, or a heat transfer fluid. The safety zone is designed to drain any refrigerant that escapes from compressed air-carrying parts of the heat exchanger in the event of a leak. Spacers can be arranged in each channel, or in at least one channel, to maintain a channel gap width.

[0007] The safety zone can include a pressure-monitored collection box. Alternatively, the safety zone can have an outlet to the surrounding atmosphere. This allows for the safe and reliable removal of flammable refrigerant in a simple and dependable manner. Furthermore, mixing with compressed air and thus the formation of an explosive atmosphere can be reliably prevented. The ingress of compressed air into the refrigeration circuit can also be reliably prevented.

[0008] Furthermore, the first devices can include at least one distribution box, at least one collection box, and additionally or alternatively at least one deflection box for the compressed air. The second devices can include at least one distribution box, at least one collection box, and additionally or alternatively at least one deflection box for the refrigerant. Such an embodiment offers the advantage that components in the outer section of the heat exchanger that are conventionally protected against leakage can also be easily upgraded with regard to fire and explosion protection.

[0009] According to one embodiment, the heat exchanger can have additional strips in the boundary regions as double wall elements, as well as strips for compressed air passages and refrigerant passages arranged in these boundary regions. The additional strips can be located in the outer section adjacent to the strips located in the boundary regions. The means for distributing, collecting, and / or diverting the refrigerant can be attached to the additional strips and, optionally, also to the strips themselves. This reliably prevents leakage of flammable refrigerant into the compressed air-carrying parts of the heat exchanger. It also prevents compressed air from entering the refrigeration circuit. Thus, the transfer of media in both directions can be prevented.

[0010] Each of the additional strips can extend over at least one of the strips located in the boundary regions. Additionally or alternatively, at least one of the additional strips can extend over several strips located in the boundary regions and, additionally or alternatively, along an entire side surface of the heat transfer block. This allows for the formation of a stable and, optionally, a full-surface outer surface of the heat exchanger. Furthermore, the safe removal of refrigerant escaping in the event of a leak can be further improved.

[0011] Additionally or alternatively, at least one of the auxiliary strips can have a through-opening. This allows for the targeted and reliable drainage of any escaping refrigerant, even if the dimensions and connection points of the auxiliary strips, or the presence of means for distributing, collecting, and / or diverting, would obstruct the outlet of a duct.

[0012] According to one embodiment, at least one of the refrigerant passages can have a contoured sheet metal unit formed in one or more pieces with nested sections. The heat exchanger can incorporate this contoured sheet metal unit as one of the double wall elements in the boundary regions. This allows for advantageous refrigerant flow and reliably prevents refrigerant leakage into the compressed air area. It also prevents compressed air from entering the refrigeration circuit.

[0013] In particular, the heat exchanger can be designed as double-walled elements with contoured sheet metal units and additional strips in the boundary regions. Alternatively, the contoured sheet metal unit can be shaped to incorporate the double-walled elements itself. Thus, even with this type of heat exchanger design featuring a contoured sheet metal unit, the channels for refrigerant drainage in case of leakage can be easily formed.

[0014] The contoured sheet metal unit can also be shaped to act as a spacer for at least one channel. Alternatively, spacers can be inserted into at least one channel. This ensures a defined gap width between the channels.

[0015] A compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer is also presented, wherein the compression refrigeration machine comprises an embodiment of a heat exchanger mentioned herein as an evaporator, a refrigerant compressor, a condenser and a fan.

[0016] The compression refrigeration machine can be used to cool compressed air, which is generally saturated with water vapor. In the evaporator, the refrigerant extracts heat from the moist compressed air, evaporating in the process. This vapor is then drawn in and compressed by the refrigerant compressor. At this higher pressure level, the heat from the refrigerant is transferred to the cooling air via the condenser. A fan creates or forces the flow of cooling air, or convection. The compression refrigeration machine can also include an additional heat exchanger. After passing through the evaporator, the cooled compressed air can be routed through this heat exchanger and used to pre-cool the incoming warm compressed air. This allows the dried compressed air to be reheated and has a lower relative humidity than the incoming compressed air.

[0017] Furthermore, a compressed air refrigeration dryer is presented, which comprises an embodiment of a compression refrigeration machine mentioned herein.

[0018] In a compressed air refrigeration dryer, the physical relationship between temperature and water vapor content of the compressed air can be used to dehumidify the compressed air by cooling it and causing the water vapor to condense. A compression refrigeration unit is used to cool the compressed air, which is generally saturated with water vapor.

[0019] The invention is explained in more detail by way of example with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a compressed air refrigeration dryer with a compression refrigeration machine according to an exemplary embodiment; Fig. 2 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 3 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 4 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 5 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 6 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 7 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 8 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 9 a schematic partial representation of a heat exchanger according to an exemplary embodiment; Fig. 10 a schematic partial representation of a heat exchanger according to an exemplary embodiment; and Fig. 11 a schematic partial representation of a heat exchanger according to an exemplary embodiment.

[0020] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0021] Fig. Figure 1 shows a schematic representation of a compressed air refrigeration dryer 100 with a compression refrigeration unit 110 according to an exemplary embodiment. Only the compression refrigeration unit 110 of the compressed air refrigeration dryer 100 is shown by way of example. The compression refrigeration unit 110 is designed to treat compressed air for the compressed air refrigeration dryer 100, more precisely to cool and dry it, or to dry it by cooling.

[0022] The compression refrigeration machine 110 comprises a refrigerant compressor 112, a condenser 114, a fan 116, and a heat exchanger 120 acting as an evaporator. The compression refrigeration machine 110 is used to cool compressed air, which is generally saturated with water vapor. A refrigerant extracts heat from the moist compressed air in the heat exchanger 120, which acts as an evaporator, thereby evaporating. The evaporated air is then drawn in and compressed by the refrigerant compressor 112. At this higher pressure level, the heat from the refrigerant is transferred to the cooling air via the condenser 114. A flow of the cooling air, or convection, is created or enforced by the fan 116. The compression refrigeration machine 110 also includes a throttling device 118, such as a capillary tube, at least one throttle valve, etc.

[0023] According to one embodiment, the compressed air refrigeration dryer 100 or the compression refrigeration machine 110 can also include a further heat exchanger, in particular an air-to-air heat exchanger for pre-cooling. The cooled compressed air can be passed through the further heat exchanger after the heat exchanger 120, which acts as an evaporator, and used to pre-cool the incoming warm compressed air. This allows the dried compressed air to be reheated and results in a lower relative moisture content than the incoming compressed air.

[0024] The heat exchanger 120, which functions as an evaporator, will be discussed in more detail with reference to the following figures.

[0025] Fig. Figure 2 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to be added]. Fig. 1. Thus, the heat exchanger 120 is used as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine.

[0026] The heat exchanger 120 comprises a heat transfer block 222 and an external section outside the heat transfer block 222. In the illustration of Fig. Figure 2 explicitly shows and labels only the heat transfer block 222, although it is clearly evident that the outer section is located outside the heat transfer block 222. A section A of the heat transfer block 222 is also shown separately enlarged in the illustration.

[0027] According to the embodiment shown here, the heat exchanger 120 is constructed from baffles 224, fins 226, and bars 228. Thus, the heat exchanger 120 is constructed according to a so-called plate-and-bar design. One possible design of the heat exchanger 120, which functions as an evaporator, can include brazed aluminum heat exchanger units.

[0028] Fig. Figure 3 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to be added]. Fig. 1. Thus, the heat exchanger 120 is used as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 comprises a heat transfer block 222 and an external section outside the heat transfer block 222. The heat transfer block 222 corresponds to or is similar to that of Fig. 2. In the illustration, a section B of the heat transfer block 222 is shown separately enlarged.

[0029] The heat transfer block 222 comprises compressed air passages 323, which are shaped to guide the compressed air through the heat transfer block 222, refrigerant passages 325, which are shaped to guide a flammable refrigerant through the heat transfer block 222, and also separating passages 327, which are arranged between the refrigerant passages 325 and the compressed air passages 323. With further reference to Fig. 2. The separating plates are arranged between the passages 323, 325, 327, with the fins arranged in the passages 323, 325, 327 and the strips serving as side walls of the passages 323, 325, 327. The heat transfer block 222 is designed to effect heat transfer between compressed air guided through the compressed air passages 323 and refrigerant guided through the refrigerant passages 325. The heat transfer takes place within the heat transfer block 222.

[0030] In other words, the heat exchanger 120 is composed of at least three different passages 323, 325, 327: There are compressed air passages 323 through which the compressed air to be dried flows, refrigerant passages 325 through which the refrigerant flows, and there are separation passages 327 or safety passages. To prevent leakage between the compressed air and the refrigerant in the heat transfer block 222 or block area, each refrigerant passage 325 is surrounded on both sides by a separation passage 327. The separation passages 327 can be empty passages that merely ensure the heat flow from the compressed air to the refrigerant and are otherwise vented to the atmosphere. However, it is also possible to use the separation passages 327 for a different medium. One possibility is to fill these separation passages 327 with a phase change material (PCM), see also Fig. 5, or to be traversed with a heat transfer medium. Apart from the fact that each refrigerant passage 325 is to be surrounded by a separation passage 327, the arrangement of the passages 323, 325, 327 is freely selectable. For example, for reasons of symmetry, several adjacent compressed air passages 323, or for reasons of minimum charge quantity, several adjacent separation passages 327, safety passages, or PCM passages can be implemented.

[0031] Fig. Figure 4 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from [reference to be added]. Fig. 1, Fig. 2 and / or Fig. 3. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine. Fig. 1 or a similar compression refrigeration machine.

[0032] In the representation of Fig. Figure 4 is a part of the heat transfer block at the transition to the outer section, more precisely two finned passages, here exemplified by a compressed air passage 323 and a refrigerant passage 325, and a part of the outer section with first means 430 and second means 440 are shown. In particular, a compressed air outlet 423 and a refrigerant passage 325 are shown. The outer section of the heat exchanger 120, located outside the heat transfer block, comprises first means 430 for distributing, collecting, and / or redirecting the compressed air from and into compressed air passages 323 of the heat transfer block and second means 440 for distributing, collecting, and / or redirecting the refrigerant from and into refrigerant passages 325 of the heat transfer block.According to one embodiment, the first means 430 comprise at least one distribution box, at least one collection box and / or at least one deflection box for the compressed air and the second means 440 comprise at least one distribution box, at least one collection box and / or at least one deflection box for the refrigerant.

[0033] To achieve a tight seal of the heat exchanger 120, the medium-contacting strips 228 are to be welded tightly at the corners 429. As mentioned above, a heat exchanger 120 of the design described herein includes the safety or separation passage between the heat-exchanging media. However, this safety or separation passage extends only to the media-carrying area that serves the direct heat exchange within the heat exchanger block. Second means 440, for example, in the form of distribution and collection boxes welded on for the supply and discharge of the refrigerant, as well as first means 430, for example, in the form of deflection boxes welded to the outside of the heat exchanger block for the return of compressed air from the evaporator area to the air-to-air area, would be excluded from the protective function of the safety or separation passage provided only within the block. A leak at a defect X, e.g.,A faulty solder joint in the aforementioned areas would lead to a transfer of media between the compressed air side and the refrigerant side. The direction of this transfer depends on the pressure conditions and / or the operating state. Typically, the individual sections of an aluminum block heat exchanger are delimited from the atmosphere or separated from each other by the strips 228. A transfer of refrigerant into the compressed air would be possible at a defect X in the area of ​​the strips 228. Defects can be caused, among other things, by poor solder or weld joints, corrosion, or the application of force, e.g., due to ice formation. To prevent this possibility of leakage, these strips 228 are doubled in the exemplary embodiments of the heat exchanger 120 and the safety heat exchanger described herein, as will be shown and described with reference to the following figures.

[0034] Fig. Figure 5 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 4 except that instead of the refrigerant passage, a separation passage 327 is shown and no leakage is illustrated. Thus, in particular, a compressed air outlet 423 and a separation passage 327 or a PCM area are shown.

[0035] According to the embodiment shown here, a phase change material (PCM) is arranged in the separation passage 327. This PCM releases heat to the refrigerant during periods when the refrigerant compressor is active and operating at excessive cooling capacity. Once the refrigerant has cooled sufficiently, the compressor can be switched off. The refrigerant then absorbs heat from the compressed air to maintain its cooling. This extends both the operating time and the downtime of the refrigerant compressor. This advantageously prevents exceeding the maximum switching frequency (starts per hour) specified by the compressor manufacturer.

[0036] Fig. Figure 6 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from one of the figures described above. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine from Fig. 1 or a similar compression refrigeration machine. The one in Fig. The part of the heat exchanger 120 shown in Figure 6 resembles a part of the one in Fig. 4 heat exchangers shown, wherein in Fig. 6 the compressed air passage 323 and the second means 440 are shown.

[0037] The heat exchanger 120 is double-walled in boundary regions 650 where secondary means 440 and compressed air passages 323 adjoin each other, with at least one channel 660 arranged between double wall elements 228, 628, leading to a safety area separate from the primary means and the compressed air passages 323. For example, the safety area includes a pressure-monitored manifold or an outlet to the atmosphere surrounding the heat exchanger 120.

[0038] According to the embodiment shown here, the heat exchanger 120 comprises additional strips 628 as double wall elements in the boundary regions 650 and strips 228 of the compressed air passage 323 arranged in the boundary regions 650. The additional strips 628 are arranged on the strips 228 arranged in the boundary regions 650. The means for distributing, collecting and / or deflecting, here the second means 440, are attached to the additional strips 628 and optionally also to the strips 228.

[0039] According to one embodiment, each of the additional strips 628 extends over at least one of the strips 228 arranged in the boundary regions 650. Additionally or alternatively, at least one of the additional strips 628 extends over several strips 228 arranged in the boundary regions 650. Additionally or alternatively, and as in Fig. As shown in Figure 6 on the right, at least one of the additional strips 628 extends along an entire side surface of the heat transfer block. Optionally, and as shown in Fig. As shown in Figure 6 on the right, at least one of the additional strips 628 has a through opening 670 to the channel 660 formed.

[0040] Fig. Figure 7 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 corresponds to or is similar to the heat exchanger functioning as an evaporator for a compression refrigeration machine from one of the figures described above. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine from Fig. 1 or a similar compression refrigeration machine. The one in Fig. The part of the heat exchanger 120 shown in Figure 7 corresponds to the one in Fig. 6. Part of the heat exchanger shown, except that in Fig. 7 the refrigerant passage 325 and the first means 430 are shown.

[0041] The heat exchanger 120 is also designed as a double-walled structure in boundary regions 650, where first means 430 and refrigerant passages 325 adjoin each other, wherein at least one channel 660 is arranged between double wall elements 228, 628, leading to the safety area separated from the first means 430 and the compressed air passages. According to the embodiment shown here, the heat exchanger 120 also comprises additional strips 628 as double wall elements in the boundary regions 650, as well as strips 228 of refrigerant passages 325 arranged in the boundary regions 650.

[0042] With reference to Fig. 6 and Fig. In other words, additional strips 628 are inserted in the refrigerant passages, specifically in part of the refrigerant passage 325 where a compressed air manifold 430 is adjacent, and in the compressed air passages, specifically in part of the compressed air passage 323 where a refrigerant manifold 440 is adjacent. These double strips 628 provide a continuous outer surface for the heat exchanger 120, onto which the corresponding manifold can be welded. Care is taken to ensure that the gap or channel 660 between the two strips 228 and 628 is not closed by welding the manifolds. If necessary for reasons of strength or improved manufacturability, the double strips 228 and 628, or at least the additional strips 628, can extend over the entire length of the heat exchanger 120.If it is not possible to keep the gaps or channels 660 open by welding on the collection boxes, the outer or additional strips or supplementary strips 628 can also be opened elsewhere, here at the passage opening 670.

[0043] Fig. Figure 8 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 4 except that only a finned compressed air passage 323 is shown at a compressed air inlet 823 and the heat exchanger 120 as in Fig. 6 in border regions 650 is double-walled. Thus, it resembles in Fig. 8 The part of the heat exchanger 120 shown also includes the one in Fig. 6. Part of the heat exchanger shown.

[0044] Fig. Figure 9 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 4 except that the refrigerant passage 325 has a one-piece or multi-piece contour sheet unit 980 with nested sections and the heat exchanger 120 as in Fig. 6 and / or Fig. 7 in border regions 650 is designed with double walls. In particular, a compressed air outlet and a refrigerant passage 325 are shown.

[0045] According to the embodiment shown here, the contour sheet unit 980, formed in one piece or in multiple pieces, with nested sections, is arranged in the refrigerant passage 325. The heat exchanger 120 incorporates the contour sheet unit 980 as one of the double wall elements in the boundary regions 650. According to the embodiment shown here, the heat exchanger has the contour sheet unit 980 and additional strips, or at least one additional strip 628, as double wall elements in the boundary regions 650.

[0046] If another strip obstructs access, and it would therefore not be readily possible to weld the strips in contact with the medium tightly at the corners, the entire refrigerant passage 325 is manufactured from one or more nested sheets, the contour sheet unit 980, to achieve a tight seal. To eliminate the risk of leakage towards the compressed air in the event of a fault, the channel 660 for the outflow of escaping medium can be formed with additional strips or auxiliary strips 628. This can be manufactured as a single piece to prevent the gap or channel 660 from being closed when the heat exchanger block is installed. In a multi-piece design, spacers can be inserted to ensure that the channel 660 or outflow channel remains open. The contour sheet unit 980 at least partially replaces the function of the strips that are usually inserted.The contour sheet unit 980 can be designed so that the entire space is used as an evaporator, resulting in a meandering refrigerant flow, or a geometrically free-form refrigerant flow path is also possible. To transfer heat to the refrigerant and ensure structural integrity, the areas within the contour sheet are filled with fins, for example. Whether certain areas, intended solely to direct the refrigerant to a specific location (in this case, a guide area 985), can be designed without fins depends on the structural requirements. A combination of strips 228 and 628 and the contour sheet unit 980 is also possible.

[0047] Fig. Figure 10 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 and the illustration correspond to the heat exchanger and the illustration from Fig. 9 except that the contour sheet unit 980 is shaped to act as a spacer for the at least one channel 660. In order to eliminate the risk of leakage towards the compressed air in the event of a fault, the contour sheet unit 980 or contour plate can thus be shaped as an alternative to additional strips in such a way that the channel 660 is directly formed for outflow.

[0048] Fig. Figure 11 shows a schematic partial representation of a heat exchanger 120 according to an exemplary embodiment. The heat exchanger 120 is designed as an evaporator for a compression refrigeration machine for treating compressed air for a compressed air refrigeration dryer. The heat exchanger 120 is designed as an evaporator for the compression refrigeration machine made of Fig. 1 or a similar compression refrigeration machine. The heat exchanger 120 corresponds to or resembles the heat exchanger from one of the figures described above. To reduce the setup effort in the manufacture of the heat exchanger 120, it is possible to use a wider strip 228 with notches 1128 on each side contacting the partition plates 224. This interruption by the notches 1128 also allows a leakage flow to escape from the heat exchanger 120.

[0049] With reference to the figures described above, features of exemplary embodiments are summarized again below and briefly presented in other words.

[0050] The refrigerant passage 325 of the heat exchanger 120 is designed by contour plate units 980 or additional strips 628, which enclose the passage between the partition plates 224, such that an intermediate space or channel 660 with a connection to the atmosphere is created, through which, in the event of a leak, escape towards the compressed air-carrying area is prevented in the inner contour plates or strips 228 enclosing the transfer fins 226. The compressed air passage 323 of the heat exchanger 120 is designed by additional components 628, which enclose the passage between the partition plates 224, such that an intermediate space or channel 660 with a connection to the atmosphere is created, through which, in the event of a leak, escape towards the refrigerant-carrying area is prevented in the inner contour plates or strips enclosing the transfer fins 226. The contour sheets inserted in the refrigeration circuit orThe strips are designed to be wide enough that, in the event of corrosion or crack growth, the defect is expected to destroy the separating plate 224 and lead to a leak into the adjacent safety area or the adjacent separation passage 327 before a leak occurs into the compressed air area or a compressed air passage 323. Leaks in the area of ​​the strips 228 can occur due to ice formation, corrosion, and defective solder joints. These mechanisms can cause the solder gap to open, allowing media to pass through. The risk of such a leak can be minimized by designing the strips 228, 628, or contour plates 980 so that the soldered area is wide enough that a defect X is more likely to penetrate into the adjacent safety passage or separation passage 327 than through the solder joint.

[0051] The embodiments described and shown in the figures are only examples. Different embodiments can be combined completely or with respect to individual features. An embodiment can also be supplemented by features from another embodiment.

[0052] If an embodiment includes an “and / or” connection between a first feature and a second feature, this can be interpreted as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2024 / 573

[0002]

Claims

[1] Heat exchanger (120) designed as an evaporator for a compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the heat exchanger (120) has the following features: a heat transfer block (222) with compressed air passages (323) shaped to guide compressed air through the heat transfer block (222), with refrigerant passages (325) shaped to guide a flammable refrigerant through the heat transfer block (222), and with separating passages (327) arranged between the refrigerant passages (325) and the compressed air passages (323), wherein the heat transfer block (222) is constructed from separating plates (224) between the passages (323, 325, 327), fins (226) in the passages (323, 325, 327), and strips (228) as side walls of the passages (323, 325, 327), and is shaped to allow heat transfer between compressed air guided through the compressed air passages (323) and through the to effect refrigerant passages (325) guided refrigerant; and an outer section arranged outside the heat transfer block (222), the outer section comprising first means (430) for distributing, collecting and / or diverting the compressed air from and into compressed air passages (323) and second means (440) for distributing, collecting and / or diverting the refrigerant from and into refrigerant passages (325), the heat exchanger (120) being formed as a double wall in boundary regions (650) where first means (430) and refrigerant passages (325) or second means (440) and compressed air passages (323) are adjacent to each other, wherein at least one channel (660) is arranged between double wall elements (228, 628, 980) which leads to a safety area separate from the first means (430) and the compressed air passages (323). [2] Heat exchanger (120) according to claim 1, wherein the safety area comprises a pressure-monitored collection box or an outlet to the surrounding atmosphere. [3] Heat exchanger (120) according to one of the preceding claims, wherein the first means (430) comprise at least one distribution box, at least one collection box and / or at least one deflection box for the compressed air, wherein the second means (440) comprise at least one distribution box, at least one collection box and / or at least one deflection box for the refrigerant. [4] Heat exchanger (120) according to one of the preceding claims, wherein the heat exchanger (120) has additional strips (628) as double wall elements in the boundary regions (650) and strips (228) of compressed air passages (323) and refrigerant passages (325) arranged in the boundary regions (650), wherein the additional strips (628) are arranged in the outer section on the strips (228) arranged in the boundary regions (650), wherein the means (430, 440) for distributing, collecting and / or deflecting are attached to the additional strips (628) and optionally additionally to the strips (228). [5] Heat exchanger (120) according to claim 4, wherein each of the additional strips (628) extends over at least one of the strips (228) arranged in the boundary regions (650), and / or wherein at least one of the additional strips (628) extends over several strips (228) arranged in the boundary regions (650) and / or along an entire side surface of the heat transfer block (222), and / or wherein a through-opening (670) is formed in at least one of the additional strips (628). [6] Heat exchanger (120) according to one of the preceding claims, wherein at least one of the refrigerant passages (325) has a contour sheet unit (980) formed in one piece or in more pieces with nested sections, wherein the heat exchanger (120) has the contour sheet unit (980) as one of the double wall elements in the boundary regions (650). [7] Heat exchanger (120) according to claim 6, wherein the heat exchanger (120) comprises the contour sheet unit (980) and additional strips (628) as double wall elements in the boundary regions (650). [8] Heat exchanger (120) according to one of claims 6 to 7, wherein the contour sheet unit (980) is shaped to act as a spacer for the at least one channel (660), or wherein spacers are inserted into the at least one channel (660). [9] Compression refrigeration machine (110) for treating compressed air for a compressed air refrigeration dryer (100), wherein the compression refrigeration machine (110) comprises a heat exchanger (120) according to one of the preceding claims as an evaporator, a refrigerant compressor (112), a condenser (114) and a fan (116). [10] Compressed air refrigeration dryer (100) with a compression refrigeration machine (110) according to claim 9.

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