Brazed sheet heat exchanger with freeze detection system

Abstract

A brazed plate heat exchanger (10) includes a plurality of heat exchanger plates (12A, 12B, 12C) stacked on one another. The heat exchanger plates (12A, 12B, 12C) are obtained by forming from respective metal sheets and are permanently joined to one another by brazing by means of a brazing material in order to form a plate group (30) provided with a first plate gap (32) for a first fluid and a second plate gap (34) for a second fluid. Each heat exchanger plate (12A, 12B, 12C) is provided with a plurality of port holes (P1, P2, P3, P4) and one or more side edges (26, 28), the one or more side edges (26, 28) forming an outer periphery of the heat exchanger plate (12A, 12B, 12C). A brazed plate heat exchanger (10) includes a plurality of cells (36) having a predetermined internal volume (V). Each unit (36) is integral with a corresponding heat exchanger plate (12A, 12B, 12C) and separated from the first plate gap (32) and / or the second plate gap (34) by a corresponding deformable wall portion (38). The deformable wall portion (38) has a mechanical strength that is lower than the average mechanical strength of the metal sheets of the heat exchanger plates (12A, 12B, 12C). At least one channel (40) is provided between each unit (36) and one of the side edges (26, 28) of the heat exchanger plates (12A, 12B, 12C), each channel (40) fluidly connecting the internal volume (V) of the respective unit (36) with the environment external to the brazed plate heat exchanger (10).

Description

Technical Field

[0001] The present invention generally relates to a plate heat exchanger, and more specifically, to a brazed plate heat exchanger used as an evaporator, wherein the heat exchanger plates are provided with an improved system for detecting freezing of at least one of two fluids flowing within the heat exchanger. Background Technology

[0002] A heat exchanger is a device used to transfer heat between two or more fluids. A plate heat exchanger is a specific type of heat exchanger in which heat is transferred between two fluids using metal plates. A plate heat exchanger generally consists of a starting plate, end plates, and multiple intermediate plates stacked on top of each other to form flow channels between them. In a plate heat exchanger, two fluids at different temperatures (one of which is often identified as a refrigerant fluid) flow respectively through plate channels obtained between the opposing surfaces of pairs of adjacent heat exchanger plates: in this way, the two fluids exchange their heat content. These fluids can flow in either countercurrent or cocurrent, and their leak-free circulation is ensured by gaskets or joints between the heat exchanger plates.

[0003] Flow channels between heat exchanger plates are typically created by applying corrugated patterns to the surfaces of the two plates. In other words, both plate surfaces have a pressed pattern of ridges and grooves. When the heat exchanger plates are stacked, the ridges of the first heat exchanger plate contact the grooves of the adjacent heat exchanger plate, and the plates are thus kept apart by spacers. This forms the flow channels.

[0004] A common manufacturing method for plate heat exchangers is to braze the heat exchanger plates together. This method requires the heat exchanger plates to have a brazing material. During manufacturing, the heat exchanger plates are stacked on top of each other and placed in a furnace at a temperature sufficient to at least partially melt the brazing material. As the furnace temperature decreases, the brazing material solidifies, allowing the heat exchanger plates to become bonded together to form a compact and robust heat exchanger.

[0005] Brazed plate heat exchangers (also known as "BHEs") can be used as evaporators. When a brazed plate heat exchanger is used as an evaporator, a first fluid (usually water) is cooled as it dissipates heat to a second fluid (i.e., the refrigerant fluid), which then evaporates. Under specific conditions of low temperature and low flow rate, freezing can occur in the water loop of a BHE evaporator. Ice formation occurs gradually due to variations in fluid temperature and flow rate in the channel region; therefore, the duration of these critical conditions is another important parameter to consider.

[0006] Even under the aforementioned critical conditions, the flow channels of the BHE evaporator can withstand water freezing without consequences. However, the situation becomes dangerous for the mechanical integrity of the BHE evaporator when some water becomes trapped in the enclosed space and refreezes, causing volume expansion. This can happen, for example, because previously formed ice can create an ice blockage around the water. The volume of ice expands by approximately 7% compared to the volume occupied by the water. If trapped, the ice exerts tremendous forces on the walls that confine it (in this case, the surface of the plate). Another effect is that the ice, as it expands, has a "piston effect" on the trapped water, thus increasing its pressure.

[0007] Plate cracking rarely occurs during the first freeze. It usually requires several (but not many) freeze-thaw-freeze cycles. Regardless, repairing a BHE evaporator cracking due to freezing is costly in terms of both money and time. Furthermore, the fact that potentially harmful refrigerants (i.e., flammable, toxic, and / or refrigerants with high GWP values) often circulate in the BHE evaporator must be considered. For these reasons, refrigerant release into the environment must be avoided for both safety and environmental reasons.

[0008] To avoid or reduce the risk of rupture, the plates of BHE evaporators used in cryogenic fluid applications are designed according to specific rules to minimize the formation of water traps. Furthermore, the operating condition limitations (the parameters mentioned above concerning fluid temperature, fluid flow rate, and duration) for a specific BHE evaporator and application are fixed. However, the actual operating conditions of a BHE evaporator are sometimes difficult to predict and control. For example, the actual water flow rate is sometimes unknown. In addition, the BHE evaporator's control system may malfunction, or its settings may be incorrect (e.g., excessively low water limit temperatures), or a combination of all these factors.

[0009] Document CN-A-113432461 discloses a brazed plate heat exchanger in which the heat exchanger plates have specific joints that act as ice loss points. These joints need to be surrounded by an elastically deformable surface of a channel through which a liquid that may experience freezing flows. Therefore, this brazed plate heat exchanger requires a complex and expensive manufacturing process to achieve the ice loss points.

[0010] Document CN-U-203274588 discloses a brazed plate heat exchanger with a receiving tank containing a temperature sensor. The purpose of the temperature sensor is to indicate the possibility of fluid freezing. However, there is only one temperature sensor, located at a specific position in the heat exchanger, and it is therefore arranged to detect the fluid temperature only at that specific position. Summary of the Invention

[0011] Therefore, one object of the present invention is to provide a brazed plate heat exchanger that can overcome the shortcomings of the prior art in a simple, inexpensive and particularly effective manner.

[0012] Specifically, one object of the present invention is to provide a brazed plate heat exchanger, particularly but not limited to its use as an evaporator, which can alert the equipment owner, and thus also the heat exchanger manufacturer, that freezing has occurred in the heat exchanger due to operating conditions, especially as early as the first freezing, at which point the damage is limited and has not yet led to any heat exchanger rupture or refrigerant leakage.

[0013] Another object of the present invention is to provide a brazed plate heat exchanger that allows the equipment owner to take corrective measures to restore the operating parameters to permissible limits and set the control parameters accordingly.

[0014] According to the present invention, these and other objectives are achieved by providing a brazed plate heat exchanger as set forth in the appended claims.

[0015] Other features of the invention are highlighted by the dependent claims, which are integral to this specification.

[0016] The brazed plate heat exchanger according to the invention comprises a plurality of heat exchanger plates stacked on top of each other. The heat exchanger plates are obtained by forming corresponding metal sheets. The heat exchanger plates are permanently connected to each other by brazing with a brazing material to form a plate assembly, the plate assembly having a first plate gap for a first fluid and a second plate gap for a second fluid. Each heat exchanger plate has a plurality of port holes and one or more side edges forming the outer periphery of the heat exchanger plate. The heat exchanger includes a plurality of units having predetermined internal volumes, wherein each unit is integral with a corresponding heat exchanger plate and separated from the first plate gap and / or the second plate gap by a corresponding deformable wall portion. The deformable wall portion has a mechanical strength lower than the average mechanical strength of the metal sheets of the heat exchanger plates. At least one channel is provided between each unit and one of the side edges of the heat exchanger plate. Each channel fluidly connects the internal volume of the corresponding unit to the external environment of the heat exchanger.

[0017] Preferably, each unit is located near one of the side edges of the heat exchanger plate. More preferably, each unit is located between one of the port holes and one of the side edges of the heat exchanger plate.

[0018] According to a preferred aspect of the invention, the deformable wall portion has an average thickness less than the average thickness of the heat exchanger plate metal sheet. Alternatively, according to another preferred aspect of the invention, the deformable wall portion is provided with one or more bends having a small radius. As another alternative, according to yet another preferred aspect of the invention, the deformable wall portion is made of a different metal material than the metal material used to manufacture the heat exchanger plate metal sheet.

[0019] According to a preferred embodiment, at least a portion of the unit is provided with a sensor device for detecting deformation and / or breakage of the deformable wall portion correspondingly associated with the unit. Preferably, the sensor device may include: - At least one colored fluid substance having a viscosity greater than that of the first fluid and the second fluid: the colored fluid substance at least partially fills the internal volume of a single unit and is arranged to leak out from the corresponding channel in the event of deformation and / or rupture of the deformable wall. - At least one conductive fluid material, which at least partially fills the internal volume of a single unit, and at least one conductive cable, which connects the internal volume of this single unit to the electronic control unit of the heat exchanger through a corresponding channel: the conductive fluid material is arranged to generate an electrical signal and transmit the electrical signal to the electronic control unit via the cable in the event of deformation and / or rupture of the deformable wall portion. - At least one elastic element that is in direct contact with the deformable wall portion of the single unit, and at least one conductive cable that connects the internal volume of this single unit to the electronic control unit of the heat exchanger through a corresponding channel and is in direct contact with the elastic element: in the event of deformation and / or rupture of the deformable wall portion, the elastic element undergoes elastic deformation, and this elastic deformation generates an electrical signal, which is transmitted to the electronic control unit via the cable.

[0020] According to a preferred embodiment of the invention, the heat exchanger comprises pairs of adjacent units, wherein the two units of a single pair of adjacent units are respectively located in two adjacent first plate gaps and / or two adjacent second plate gaps. The two units in a single pair of adjacent units are separated from each other and from the adjacent first plate gaps and / or adjacent second plate gaps by at least one deformable wall portion.

[0021] Preferably, pairs of adjacent units are interconnected by connecting conduits, which are in turn fluidly connected via at least one channel to a single side opening obtained on one side edge of the heat exchanger plate. More preferably, these pairs of adjacent units and connecting conduits are filled with an inert gas. Even more preferably, at least one probe is connected to the side opening. This probe is capable of detecting changes in the pressure and / or temperature of the inert gas.

[0022] According to another preferred embodiment of the invention, the heat exchanger includes one or more fluid collection tanks located outside the heat exchanger and designed to collect fluid exiting through at least one channel. The fluid collection tanks are preferably equipped with one or more level sensors and / or one or more overflow discharge conduits. Attached Figure Description

[0023] Referring to the accompanying schematic diagrams, the features and advantages of the brazed plate heat exchanger according to the present invention will become clearer from the following exemplary and non-limiting description: Figure 1 This is a side view of a general embodiment of a brazed plate heat exchanger; Figure 2 yes Figure 1 A plan view of a brazed plate heat exchanger; Figure 3 yes Figure 1 A schematic partial cross-sectional view of a brazed plate heat exchanger, wherein the main components of the freeze detection system according to the invention are shown in its first embodiment; Figure 4 This is a schematic perspective view of the components of the freeze detection system; Figure 5 yes Figure 1 Another schematic partial cross-sectional view of a brazed plate heat exchanger, wherein the main components of the freeze detection system according to the invention are shown in its second embodiment; Figure 6A and 6B The corresponding possible locations of the components of the freeze detection system are shown; Figure 7 yes Figure 1 Another partial cross-sectional view of the brazed plate heat exchanger shows the operation of the freeze detection system according to the invention; Figure 8 yes Figure 1 Another partial cross-sectional view of the brazed plate heat exchanger shows more components of the freeze detection system; Figure 9 yes Figure 1 Another partial cross-sectional view of a brazed plate heat exchanger, in which the main components of the freeze detection system are shown in its third embodiment; Figure 10 It is a display Figure 9 A cross-sectional view of the operation of the freeze detection system; Figure 11 This is another sectional view, showing Figure 9 The operation of the freeze detection system; Figure 12 This is another sectional view, showing Figure 9 Other components of the freeze detection system; Figure 13 This is a schematic diagram showing other components of the freeze detection system according to the present invention. Detailed Implementation

[0024] Special Reference Figure 1 and Figure 2 The image shows a brazed plate heat exchanger 10. The heat exchanger 10 comprises a plurality of heat exchanger plates 12A, 12B, and 12C stacked on top of each other in a manner known per se. Typically, the heat exchanger plates 12A, 12B, and 12C are stacked between a first end plate 14 and a second end plate 16 of the heat exchanger 10. Each heat exchanger plate 12A, 12B, and 12C is obtained by forming from a corresponding metal sheet. The first end plate 14, the second end plate 16, and the heat exchanger plates 12A, 12B, and 12C are permanently connected to each other by brazing using brazing material to form a plate assembly 30. Thus, the plate assembly 30 is provided with (see, for example, [reference]). Figure 3 The heat exchanger 10 has a first plate gap 32 for the first fluid and a second plate gap 34 for the second fluid. The first and second fluids can be any suitable heat transfer fluid. For example, the first fluid can be a hotter fluid, and the second fluid can be a colder fluid. Therefore, the second fluid is a cooling fluid, and it absorbs heat from the first fluid. More specifically, if the heat exchanger 10 is used as an evaporator, the first fluid can be water, and the second fluid can be a refrigerant fluid.

[0025] Each heat exchanger plate 12A, 12B, 12C, as well as the first end plate 14 and the second end plate 16, is provided with multiple port holes, preferably four port holes P1, P2, P3, and P4. The first port hole P1 connects to the first connecting pipe 18 and communicates with the first plate gap 32. The second port hole P2 connects to the second connecting pipe 20 and communicates with the first plate gap 32. The third port hole P3 connects to the third connecting pipe 22 and communicates with the second plate gap 34. Finally, the fourth port hole P4 connects to the fourth connecting pipe 24 and communicates with the second plate gap 34. The connecting pipes 18, 20, 22, and 24 can be configured as follows: Figure 1 As shown, it extends from the first end plate 14 and / or from the second end plate 16.

[0026] Each heat exchanger plate 12A, 12B, 12C, as well as the first end plate 14 and the second end plate 16, can have the shape of any planar figure enclosed by closed lines, such as a convex polygon or even a circle. Each heat exchanger plate 12A, 12B, 12C, as well as the first end plate 14 and the second end plate 16, thus has one or more side edges 26, 28, which form the outer periphery of the heat exchanger plates 12A, 12B, 12C, 14, 16. Preferably, as Figure 1 and Figure 2As shown, the heat exchanger plates 12A, 12B, 12C, the first end plate 14, and the second end plate 16 have a generally rectangular shape, with two long side edges 26 and two short side edges 28, as shown. Figure 2 As shown in the figure, the longitudinal axis X extends parallel to the two long side edges 26 and laterally to the two short side edges 28.

[0027] According to the present invention, the heat exchanger 10 includes a plurality of cavity structures or units 36 having a predetermined internal volume V. Each unit 36 ​​is integral with a corresponding heat exchanger plate 12A, 12B, 12C and is separated from the first plate gap 32 and / or the second plate gap 34 by a corresponding deformable wall portion 38. In other words, each unit 36 ​​limits one of the first plate gaps 32 and / or one of the second plate gaps 34 by the corresponding deformable wall portion 38. Then, each unit 36 ​​seals the first plate gap 32 and / or the second plate gap 34 by one or more planar brazed joints. For example, as... Figure 3 As shown, unit 36 ​​can form contact with the first plate gap 32 of heat exchanger 10, and a first fluid (such as water) that can be frozen flows inside the first plate gap 32.

[0028] The deformable wall portion 38, which partially surrounds the internal volume V enclosed by unit 36, has a lower mechanical strength than the average mechanical strength of the metal sheets of heat exchanger plates 12A, 12B, and 12C. In mechanics of materials, "mechanical strength" refers to the ability of a material to withstand an applied load without failure or plastic deformation. In this application, "lower mechanical strength" means that the deformable wall portion 38 is mechanically weaker than the surrounding wall portion of the plate gaps 32 and / or 34 between heat exchanger plates 12A, 12B, and 12C. In other words, the deformable wall portion 38 is weaker than the surrounding wall portion of the plate gaps 32 and / or 34 due to ice I ( Figure 3 The earliest wall portions that deform or even break under critical conditions. Simultaneously, these deformable wall portions 38 are sufficiently robust to withstand the fluid (water W, see [reference]) flowing into the plate gaps 32 and / or 34. Figure 3 (Normal pressure)

[0029] The lower mechanical strength of the deformable wall portion 38 relative to the other wall portions of the heat exchanger plates 12A, 12B, and 12C can be achieved in several ways. For example, the deformable wall portion 38 can have an average thickness less than the average thickness of the metal sheets of the heat exchanger plates 12A, 12B, and 12C. Alternatively or additionally, the deformable wall portion 38 can be provided with one or more bends having a small radius. As another alternative, the deformable wall portion 38 can be made of a different metal material than the metal material used to manufacture the metal sheets of the heat exchanger plates 12A, 12B, and 12C. Another possible alternative to achieving lower mechanical strength in the deformable wall portion 38 could be increasing the distance between adjacent brazed joints connecting the respective units 36 to the first plate gap 32 and / or the second plate gap 34.

[0030] Deformation of wall portion 38, and consequently of the corresponding unit 36, absorbs some of the increase in fluid volume and causes only limited and easily recoverable failure to heat exchanger 10 and the equipment operating within it. The advantage is that even with minor damage, heat exchanger 10 will not leak and can continue to operate without replacement. Deformation of wall portion 38, and consequently of the corresponding unit 36, can serve as a signal that a critical freezing condition has reached the plate gaps 32 and / or 34 of heat exchanger 10. Due to this deformation, heat exchanger 10 can only operate effectively once (or a few times). However, it is recommended to repair the damaged heat exchanger 10 as soon as possible, primarily to prevent the release of one of the two fluids (typically refrigerant) into the environment. Generally, the rule is that once freezing is first detected in this manner, the equipment owner must reset and upgrade the equipment's operating condition to restore safe operating conditions and thus prevent those critical conditions from being reached at other times.

[0031] like Figure 4 As better shown, at least one channel 40 is disposed between each unit 36 ​​and one of the side edges 26, 28 of the heat exchanger plates 12A, 12B, 12C. Each channel 40 fluidly connects the internal volume V of the corresponding unit 36 ​​to the external environment of the heat exchanger 10. Each channel 40 is a small-diameter channel similar to a nozzle. The advantage of the channel 40 is that even if the wall portion 38, and therefore the corresponding unit 36, cracks due to freezing, the subsequently melted fluid (water W) will leak into the external environment through the corresponding channel 40 (see [reference]). Figure 7 When this occurs, the static pressure in the water circuit drops, and this can also be a sign of a malfunction. Water leaks through channel 40 are easily detected and then repaired (e.g., by sealing channel 40 with glue), also because the pressure is low and the fluid (water) is not hazardous. Similar to deformation conditions, this works once: corrective measures are then required for the operating parameters of heat exchanger 10 and / or the entire equipment.

[0032] exist Figure 6A and 6B The diagram shows two possible locations for a single unit 36 ​​and its corresponding channel 40. For example, each unit 36 ​​may be located near one of the side edges 26, 28 of the heat exchanger plates 12A, 12B, 12C. Alternatively, or additionally, each unit 36 ​​may also be located between one of the side edges 26, 28 of the heat exchanger plates 12A, 12B, 12C and one of the port holes P1, P2, P3, P4. Generally, the location of the unit 36 ​​can be determined based on fluid dynamics analysis (which can be performed using fluid dynamics software, laboratory and field test results, etc.). If necessary, more than one unit 36 ​​may be placed at different points on the heat exchanger plates 12A, 12B, 12C.

[0033] According to a preferred aspect of the invention, at least some of the units 36 may be provided with sensor devices for detecting deformation and / or breakage of the deformable wall portions 38 correspondingly associated with these units 36. The sensor devices (some embodiments of which are schematically shown in...) Figure 8 (As shown in the image) can be placed inside and / or connected to unit 36. When water W freezes, its volume increases, and it elastically or permanently deforms or even breaks the wall portion 38 of unit 36. The sensor device thereby detects the deformation and / or breakage and issues a warning signal as part of the freeze detection system.

[0034] Sensor devices can be of many types. For example, such as Figure 8 As shown, the sensor device may include at least one colored fluid substance 42 having a viscosity greater than that of the first and second fluids flowing into the heat exchanger 10. This colored fluid substance 42 may be a high-viscosity, colored, oily substance. This colored fluid substance 42 at least partially fills the internal volume V of a single unit 36 ​​and is arranged to leak out from the corresponding channel 40 in the event of deformation and / or rupture of the corresponding deformable wall portion 38. In other words, once the unit 36 ​​is compressed and / or the corresponding deformable wall portion 38 is deformed or ruptured, this colored fluid substance 42 is ejected from the heat exchanger 10 through the corresponding channel 40 and becomes externally visible.

[0035] According to different embodiments (also in) Figure 8As shown in the diagram, the sensor device may include at least one conductive fluid material 44 that at least partially fills the internal volume V of a single unit 36, and at least one conductive cable 46 that connects the internal volume V of this single unit 36 ​​to the electronic control unit 50 of the heat exchanger 10 via a corresponding channel 40. In the event of deformation and / or rupture of the deformable wall portion 38 of the unit 36, the conductive fluid material 44 is arranged to generate an electrical signal and transmit it to the electronic control unit 50 via the cable 46. For example, the conductive fluid material 44 may be a grease-like conductive material that is squeezed onto the conductive cable 46, thereby short-circuiting (closing the circuit) the ends of the conductors of the conductive cable 46.

[0036] According to still in Figure 8 In another embodiment shown, the sensor device may include at least one elastic element 48 in direct contact with the deformable wall portion 38 of the individual unit 36; and at least one conductive cable 46 connected via a corresponding channel 40 to the internal volume V of the individual unit 36 ​​to the electronic control unit 50 of the heat exchanger 10, and in direct (physical) contact with the elastic element 48. In the event of deformation and / or breakage of the deformable wall portion 38, the elastic element 48 undergoes elastic deformation: this elastic deformation generates an electrical signal, which is transmitted to the electronic control unit 50 via the cable 46. For example, the elastic element 48 may be a spring, or any mechanical / electrical / electronic component compressed onto the conductive cable 46 to short-circuit (close the circuit) the ends of its conductors.

[0037] like Figure 9 As shown in the embodiments, the heat exchanger 10 may advantageously include pairs of adjacent units 36 obtained on both sides of a partition wall between two adjacent first plate gaps 32 and / or even between two adjacent second plate gaps 34. Thus, the two units 36 of a single pair of adjacent units 36 are correspondingly located in the two adjacent first plate gaps 32 and / or the two adjacent second plate gaps 34. These two units 36 of a single pair of adjacent units 36 are separated from each other by at least one deformable wall portion 38 and are also separated from the adjacent first plate gaps 32 and / or the adjacent second plate gaps 34.

[0038] Preferably, such as Figure 10As shown, pairs of adjacent units 36 are interconnected via connecting conduits 52. The connecting conduits 52 are in turn fluidly connected via at least one of the channels 40 to a single side opening 54 obtained on one of the side edges 26, 28 of the heat exchanger plates 12A, 12B, 12C. If ice formation causes the deformable wall portion 38 of one or more units 36 to rupture, water leakage will fill all of these units 36, and therefore, regardless of which unit 36 ​​is actually involved, the water leakage will always be driven to the outside, reaching a single point on the heat exchanger 10, namely the single side opening 54. With only one external leak point, the leak is therefore easier to detect or even sense. As in the previously described embodiments, the side opening 54 can also be easily blocked to stop the water leakage and allow the heat exchanger 10 to operate until a planned repair. For example, the sensor devices described so far can send appropriate signals to the electronic control unit 50 to activate an "emergency mode," thereby allowing the heat exchanger 10 to continue operating under certain limitations. This will allow any further freezing inside the heat exchanger 10 to be avoided (e.g., by not defrosting the external coils, raising the minimum water temperature setpoint, reducing the compressor speed, etc.). In this way, the heat exchanger 10 can remain operational and provide at least some heating or cooling until its scheduled maintenance / replacement.

[0039] refer to Figure 12 All units 36 and their corresponding connecting pipes 52 may be filled with inert gas. At least one probe 56 may be connected to the side opening 54. The probe 56 may be a pressure or temperature sensor capable of detecting changes in the inert gas pressure and / or temperature. Thus, the probe 56 can detect when the volume of unit 36 ​​changes due to deformation and / or cracking caused by ice formation.

[0040] refer to Figure 13 This illustrates other components of the freeze detection system according to the invention. These components include one or more fluid collection tanks 58, 60 located outside the heat exchanger 10 and designed to collect fluid exiting through at least one of the channels 40. More specifically, the first collection tank 58 may be designed to collect fluid according to... Figure 3 In one embodiment, fluid exits from multiple channels 40 of the heat exchanger 10, while the second collection tank 60 can be designed to collect fluid according to... Figure 10 The embodiment exits the heat exchanger 10 through a single channel 40 and a single side opening 54. Preferably, at least one of the collection tanks 58, 60 may be provided with one or more level sensors 62 and / or one or more overflow discharge conduits 64 to monitor the fluid volume and discharge excess amount if necessary.

[0041] Therefore, the brazed plate heat exchanger according to the present invention achieves the objectives outlined above.

[0042] Therefore, the brazed plate heat exchanger of the present invention can be modified and varied in any situation, all of which fall under the same inventive concept; moreover, all details can be replaced by technically equivalent components. In fact, the materials used, as well as the shape and size, can be of any type according to technical requirements.

[0043] Therefore, the scope of protection of this invention is defined by the appended claims.

[0044] List of labels 10: Brazed plate heat exchanger; 12A: Heat exchanger plate; 12B: Heat exchanger plate; 12C: Heat exchanger plate; 14: First end plate; 16: Second end plate; 18: First connecting pipe; 20: Second connecting pipe; 22: Third connecting pipe; 24: Fourth connecting pipe; 26: The long side edge of the board; 28: Short side edge of the board; 30: Plate assembly; 32: Gap between the first plates; 34: Gap between the second plates; 36: Unit; 38: Deformable wall section; 40: Channel; 42: Colored fluid substances; 44: Conductive fluid material; 46: Conductive cable; 48: Elastic element; 50: Electronic control unit; 52: Connecting conduit; 54: Side opening; 56: Probe; 58: First fluid collection tank; 60: Second fluid collection tank; 62: Liquid level sensor; 64: Overflow discharge duct; P1: First port hole; P2: Second port hole; P3: Third port hole; P4: Fourth port hole.

Claims

1. A brazed plate heat exchanger (10) comprising a plurality of heat exchanger plates (12A, 12B, 12C) stacked on top of each other, wherein, The heat exchanger plates (12A, 12B, 12C) are formed from corresponding metal sheets, wherein the heat exchanger plates (12A, 12B, 12C) are permanently connected to each other by brazing with brazing material to form a plate assembly (30), the plate assembly (30) having a first plate gap (32) for a first fluid and a second plate gap (34) for a second fluid, wherein each of the heat exchanger plates (12A, 12B, 12C) has a plurality of port holes (P1, P2, P3, P4), and wherein each of the heat exchanger plates (12A, 12B, 12C) has one or more side edges (26, 28), the one or more side edges (26, 28) forming the outer periphery of the heat exchanger plates (12A, 12B, 12C), the brazed plate heat exchanger (10) being characterized in that it comprises: A plurality of units (36) having a predetermined internal volume (V), wherein each unit (36) is integral with a corresponding heat exchanger plate (12A, 12B, 12C), wherein each unit (36) is separated from the first plate gap (32) and / or the second plate gap (34) by a corresponding deformable wall portion (38), wherein the deformable wall portion (38) has a mechanical strength lower than the average mechanical strength of the metal sheet of the heat exchanger plate (12A, 12B, 12C), and wherein at least one channel (40) is provided between each unit (36) and one of the side edges (26, 28) of the heat exchanger plate (12A, 12B, 12C), wherein each channel (40) fluidly connects the internal volume (V) of the corresponding unit (36) to the environment outside the brazed plate heat exchanger (10).

2. The brazed plate heat exchanger (10) according to claim 1, characterized in that, Each unit (36) is located near one of the side edges (26, 28) of the heat exchanger plates (12A, 12B, 12C).

3. The brazed plate heat exchanger (10) according to claim 1 or 2, characterized in that, Each unit (36) is located between one of the port holes (P1, P2, P3, P4) and one of the side edges (26, 28) of the heat exchanger plates (12A, 12B, 12C).

4. The brazed plate heat exchanger (10) according to any one of claims 1 to 3, characterized in that, The deformable wall portion (38) has an average thickness that is less than the average thickness of the metal sheet of the heat exchanger plates (12A, 12B, 12C).

5. The brazed plate heat exchanger (10) according to any one of claims 1 to 4, characterized in that, The deformable wall portion (38) is provided with one or more bends with a small radius.

6. The brazed plate heat exchanger (10) according to any one of claims 1 to 5, characterized in that, The deformable wall portion (38) is made of a different metal material than the metal material of the metal sheet used to manufacture the heat exchanger plates (12A, 12B, 12C).

7. The brazed plate heat exchanger (10) according to any one of claims 1 to 6, characterized in that, At least a portion of the unit (36) is provided with sensor devices (42, 44, 46, 48) for detecting deformation and / or breakage of the deformable wall portion (38) correspondingly associated with the unit (36).

8. The brazed plate heat exchanger (10) according to claim 7, characterized in that, The sensor device includes at least one colored fluid material (42) having a viscosity greater than that of the first fluid and the second fluid, wherein the colored fluid material at least partially fills the internal volume (V) of the individual unit (36) and is arranged to leak from the corresponding channel (40) in the event of deformation and / or rupture of the deformable wall portion (38).

9. The brazed plate heat exchanger (10) according to claim 7, characterized in that, The sensor device includes at least one conductive fluid material (44) that at least partially fills the internal volume (V) of the individual unit (36), and at least one conductive cable (46) that connects the internal volume (V) of the individual unit (36) to the electronic control unit (50) of the brazed plate heat exchanger (10) via the corresponding channel (40), wherein the conductive fluid material (44) is arranged to generate an electrical signal and transmit the electrical signal to the electronic control unit (50) via the cable (46) in the event of deformation and / or rupture of the deformable wall portion (38).

10. The brazed plate heat exchanger (10) according to claim 7, characterized in that, The sensor device includes at least one elastic element (48) in direct contact with the deformable wall portion (38) of the individual unit (36), and at least one conductive cable (46) that connects the internal volume (V) of the individual unit (36) to the electronic control unit (50) of the heat exchanger (10) via the corresponding channel (40) and is in direct contact with the elastic element (48), wherein elastic deformation of the elastic element (48) occurs in the event of deformation and / or breakage of the deformable wall portion (38), and wherein the elastic deformation generates an electrical signal and transmits the electrical signal to the electronic control unit (50) via the cable (46).

11. The brazed plate heat exchanger (10) according to any one of claims 1 to 10, characterized in that, It includes pairs of adjacent units (36), wherein the two units (36) of a single pair of adjacent units (36) are respectively located in two adjacent first plate gaps (32) and / or two adjacent second plate gaps (34), and wherein the two units (36) of a single pair of adjacent units (36) are separated from each other by at least one deformable wall portion (38) and are separated from the adjacent first plate gaps (32) and / or the adjacent second plate gaps (34).

12. The brazed plate heat exchanger (10) according to claim 11, characterized in that, The pairs of adjacent units (36) are interconnected by connecting conduits (52), wherein the connecting conduits (52) are fluidly connected to a single side opening (54) obtained on one of the side edges (26, 28) of the heat exchanger plates (12A, 12B, 12C) through at least one of the channels (40).

13. The brazed plate heat exchanger (10) according to claim 12, characterized in that, The paired adjacent units (36) and the connecting conduit (52) are filled with inert gas.

14. The brazed plate heat exchanger (10) according to claim 13, characterized in that, At least one probe (56) is connected to the side opening (54), wherein the probe (56) is capable of detecting changes in the pressure and / or temperature of the inert gas.

15. The brazed plate heat exchanger (10) according to any one of claims 1 to 14, characterized in that, It includes one or more fluid collection tanks (58, 60), the one or more side edges (26, 28) being located outside the brazed plate heat exchanger (10) and designed to collect fluid leaving the heat exchanger (10) through the at least one channel (40), wherein the fluid collection tanks (58, 60) are preferably provided with one or more level sensors (62) and / or one or more overflow discharge conduits (64).

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