DE102020131370A1 - Plate heat exchanger with baffles that conduct the flow - Google Patents

Abstract

A plate heat exchanger contains a stack of pairs of plates arranged within a housing. Comb-like baffles extend into the flow gaps between the pairs of plates to direct fluid flow in a sinusoidal pattern within the flow gaps. The flow gaps are divided into two subsets of the flow gaps, which are preferably arranged alternately along the height of the stack. The legs of some baffles extend into the first subset but not into the second subset, while the legs of some baffles extend into the second subset but not into the first subset. The baffles are arranged such that the sinusoidal pattern in the second subset is out of phase with the sinusoidal pattern in the first subset.

Description

BACKGROUND

The present invention relates to heat exchangers and, more particularly, to plate heat exchangers.

Plate heat exchangers are used to transfer heat between two fluids, typically two liquids. In a common construction of such a heat exchanger, the plates are arranged in pairs and assembled in a stack. The plates of the stack are usually brazed together to form a monolithic structure with internal flow structures through which one of the fluids circulates while the other fluid flows over the outer surfaces of the plates. The two fluids are thereby brought into heat transfer with one another while remaining physically separate from one another.

Plate heat exchangers of the type mentioned above can be accommodated within a housing in order to receive and conduct the externally flowing fluid.

While flow turbulence features such. B. fins or inserts, can easily be inserted into each of the plate pairs to direct the internally flowing fluid and provide improved convective heat transfer for that fluid, the outer surfaces of the plate pairs are often not as improved. This can result in the overall efficiency of the heat exchanger being limited by the rate of convective heat transfer between the outer surfaces of the plate pairs and the externally flowing fluid.

SUMMARY

A plate heat exchanger having high thermal efficiency is provided via a stack of plates arranged within a housing, the housing defining a volume for fluid to flow therethrough. The fluid can be a liquid, e.g. B. a coolant such. B. water or glycol or a water / glycol mixture. The fluid can alternatively be another liquid, such as e.g. B. an oil. Again, alternatively, the fluid can be a gas.

The fluid flowing through the volume is in heat transfer with another fluid flowing through the internal structures of the plates. This heat transfer can result in the transfer of thermal energy from the other fluid to the fluid flowing through the volume so that the fluid flowing through the volume serves to cool the other fluid. Alternatively, the heat transfer can lead to the transfer of thermal energy from the fluid flowing through the volume to the other fluid, so that the fluid flowing through the volume serves to heat the other fluid.

The fluid flowing through the plates can be a liquid such as e.g. B. an oil. Alternatively, the fluid flowing through the plates can be a gas or a two-phase fluid that is temporarily a liquid and otherwise a gas. In such cases, the plate heat exchanger can be used to condense the other fluid from one gas phase to a liquid phase while the other fluid is flowing through the plates, or to evaporate the other fluid from a liquid phase to a gas phase while the other Fluid flows through the plates. In a specific such application, the plate heat exchanger can be used as an evaporator for liquefied natural gas (LNG) or liquefied petroleum gas (LPG) in an engine system that uses LNG or LPG as a fuel.

The plates within the stack can be arranged in pairs so that each plate pair forms a plate arrangement through which the other fluid can flow. A turbulator insert may be disposed within each such pair of plates to reinforce the pair of plates against internal pressurization, or to increase the rate of heat transfer within the pair of plates, or both. The end faces of adjacent pairs of plates can be spaced from one another so that flow gaps are arranged between them. This enables the fluid flowing through the volume to flow over these end faces in order to efficiently exchange thermal energy with the other fluid flowing through the pair of plates at the same time. An additional flow gap can be provided between the outermost of the pairs of plates (e.g. the end pair of plates at each end of the stack in the stacking direction) and the housing walls.

The geometry of the plate pairs can be such that the plate pair has a larger dimension in one direction (the longitudinal direction) than in the other direction (the transverse direction). This allows for more effective overall heat transfer because both fluids can be directed to flow in the longitudinal direction.

The plate heat exchanger can also be provided with comb-like baffles which extend into the flow gaps in order to direct the flow of the fluid as it flows through the flow gaps. These comb-like baffles can be arranged to cause that the fluid is repeatedly directed to flow in the transverse direction as it moves in an overall longitudinal direction through the flow gaps. This has the effect of increasing the overall length of the flow path and results in a greater rate of convective heat transfer due to higher Reynolds numbers in the fluid flow. The alternating reciprocating movement of the fluid in the transverse direction as the fluid moves in an overall longitudinal direction creates a sinusoidal flow path for the fluid within each flow gap.

The flow gaps can consist of a first and a second subset of the flow gaps. The flow gaps of the first subset can be arranged alternately with the flow gaps of the second subset. In some implementations, however, the flow gaps of the first and second subsets can be arranged in other patterns.

The baffles can be used to define a sinusoidal flow path in each of the flow gaps of the second subset that is out of phase with a sinusoidal flow path that the baffles define in each of the flow gaps of the first subset. By out of phase it is meant that the sinusoidal flow pattern in each of the flow gaps of the second subset is longitudinally offset from the sinusoidal flow pattern in each of the flow gaps of the first subset by a generally fixed distance expressed as a percentage of the period of the sinusoidal flow pattern can. This percentage can be expressed as an angular phase shift by considering the full period of the sinusoidal flow pattern equal to 360 °.

The phase shifting of the sinusoidal flow patterns in the first and second subsets of the flow gaps can be used to minimize the undesirable heat transfer effects of convective dead zones that tend to occur immediately downstream of each baffle. Since the baffles block the flow of fluid in the longitudinal direction and cause it to flow in the transverse direction, the fluid has a higher average velocity at the upstream face of the flow baffle and a lower average velocity at the downstream face with correspondingly higher Reynolds numbers and Heat transfer coefficients on the upstream end faces and correspondingly lower Reynolds numbers and heat transfer coefficients on the downstream end faces.

If the flow gaps of the first subset and the flow gaps of the second subset are arranged alternately, each pair of plates has a plate that delimits a flow gap of the first subset and a plate that delimits a flow gap of the second subset. By phase shifting the sinusoidal flow patterns on either side of the pair of plates, the areas of lower heat transfer on one plate of the pair can be brought into line with the areas of higher heat transfer on the other plate of the pair. This can lead to a better overall heat transfer efficiency of the heat exchanger.

In some embodiments, the sinusoidal flow paths in the flow gaps of the second subset are 180 ° out of phase with the sinusoidal flow paths in the flow gaps of the first subset. In other embodiments, the sinusoidal flow paths in the flow gaps of the second subset are out of phase with the sinusoidal flow paths in the flow gaps of the first subset by no more than 90 °. This can result in a more uniform rate of overall heat transfer along the lengthwise direction. In some specific embodiments of this type, the sinusoidal flow paths in the flow gaps of the second subset are phase-shifted by approximately 60 ° from the sinusoidal flow paths in the flow gaps of the first subset. In other embodiments, the sinusoidal flow paths are out of phase by an amount between 60 ° and 90 °, and in still other embodiments the sinusoidal flow paths are less than 60 ° out of phase.

Outwardly facing depressions may be provided on the plates to provide the desired spacing between the pairs of plates. These depressions can be arranged in a repeating pattern, with the depressions of adjacent plates which face one another being oriented so that the depressions abut one another, thereby creating the flow gaps. The plate pairs can over such abutting wells, for. B. by brazed joints, are interconnected to create a monolithic stack structure.

The pattern of the depressions may be constructed such that the depressions are arranged in rows that extend in the transverse direction. This can make it possible for the comb-like baffles to be arranged between the rows of depressions. In some embodiments, the pattern of the depressions is a grid-like pattern, wherein the depressions are arranged both in columns extending in the longitudinal direction and in rows extending in the transverse direction. Such a pattern of pits may be a staggered pattern in which alternating rows have pits in alternating columns. Alternatively, such a pattern of the pits may be a non-staggered pattern. The pattern of indentations can also provide an arrangement of indentations in rows that are oriented at a non-perpendicular angle to both the longitudinal and transverse directions. Such an arrangement can enable the baffles to extend into the flow gaps between such rows at an angle to the transverse direction.

Each of the plate pairs can be provided with a first edge and a second edge, both of which extend in the longitudinal direction of the plate pair. The plate heat exchanger may include one or more first flow baffles disposed within the housing. In some embodiments, the plate heat exchanger has only one such first flow guide plate, while in other embodiments the plate heat exchanger has more than one such first flow guide plate. Each of the one or more first flow baffles may be provided with legs that extend from the first edges of the plate pairs into some, but not all, of the flow gaps. The legs extend into a first subset of the flow gaps, but not into a second subset of the flow gaps. In this way, the legs of the first flow guide plates serve to deflect the fluid flowing in the first subset of the flow gaps, but they do not influence the fluid flowing in the second subset of the flow gaps.

In some embodiments, the legs of the first flow baffles can extend over more than half the dimension of the plate pairs in the transverse direction. Such an expansion of the legs can serve to appropriately guide the fluid flowing in the first subset of the flow gaps in the transverse direction away from the first edges. The legs may have terminal ends that are spaced from the second edges of the pairs of plates, e.g. i.e., located between the first edges and the second edges along the transverse direction. This can enable the fluid flowing in the first subset of the flow gaps to flow between these terminating ends and a wall of the housing which is located adjacent to the second edges, so that the flow of the fluid can continue along the longitudinal direction.

The plate heat exchanger can also include one or more second flow baffles disposed within the housing. In some embodiments, the plate heat exchanger has only one such second flow baffle, while in other embodiments the plate heat exchanger has more than one such second flow baffle. Each of the one or more second flow baffles may be provided with legs that extend from the second edges of the plate pairs into some, but not all, of the flow gaps. The legs of the one or more second flow baffles can extend into the second subset of the flow gaps, but not into the first subset, so that the legs of the second flow baffles deflect the fluid flowing in the second subset of the flow gaps, but that in the first subset the flow gap does not affect the flowing fluid.

In some embodiments, the legs of the second flow baffles can extend over more than half the dimension of the plate pairs in the transverse direction. Such an expansion of the legs can serve to appropriately guide the fluid flowing in the second subset of the flow gaps in the transverse direction away from the second edges. The legs may have terminal ends that are spaced from the first edges of the pairs of plates, i.e. i.e., located between the first edges and the second edges along the transverse direction. This can make it possible for the fluid flowing in the second subset of the flow gaps to flow between these terminating ends and a wall of the housing which is located adjacent to the first edges, so that the fluid flow can continue along the longitudinal direction.

The plate heat exchanger can also include one or more third flow baffles disposed within the housing. In some embodiments the plate heat exchanger has only one such third flow baffle, while in other embodiments the plate heat exchanger has more than one such third flow baffle. Each of the one or more third flow baffles can be provided with legs that extend from the second edges of the plate pairs in the first subset of the flow gaps, but not in the second subset, so that the legs of the third flow baffle in the first subset of the Divert flow gaps flowing fluid, but do not influence the fluid flowing in the second subset of the flow gaps.

In some embodiments, the legs of the third flow guide plates can extend over more extend than half the dimension of the plate pairs in the transverse direction. Such an expansion of the legs can serve to appropriately guide the fluid flowing in the first subset of the flow gaps in the transverse direction away from the second edges. The legs may have terminal ends that are spaced apart from the first edges of the plate pairs, that is, located between the first edges and the second edges along the transverse direction. This can enable the fluid flowing in the first subset of the flow gaps to flow between these terminating ends and a wall of the housing which is located adjacent to the second edges, so that the flow of the fluid can continue along the longitudinal direction.

The plate heat exchanger can also include one or more fourth flow baffles disposed within the housing. In some embodiments, the plate heat exchanger has only one such fourth flow baffle, while in other embodiments the plate heat exchanger has more than one such fourth flow baffle. Each of the one or more fourth flow baffles can be provided with legs that extend from the first edges of the plate pairs into the second subset of the flow gaps, but not into the first subset, so that the legs of the third flow baffles in the second subset of the Divert flow gaps flowing fluid, but do not influence the fluid flowing in the first subset of the flow gaps.

In some embodiments, the legs of the fourth flow baffles can extend over more than half the dimension of the plate pairs in the transverse direction. Such an expansion of the legs can serve to appropriately guide the fluid flowing in the second subset of the flow gaps in the transverse direction away from the first edges. The legs may have terminal ends that are spaced from the second edges of the pairs of plates, e.g. i.e., located between the first edges and the second edges along the transverse direction. This can enable the fluid flowing in the second subset of the flow gaps to flow between these terminating ends and a wall of the housing which is located adjacent to the second edges, so that the flow of the fluid can continue along the longitudinal direction.

In some embodiments, each of the one or more first flow baffles is longitudinally aligned with one of the one or more second baffles. In some embodiments, each of the one or more third flow baffles is longitudinally aligned with one of the one or more fourth baffles. In other embodiments, the first, second, third, and fourth baffles are all staggered along the lengthwise direction, and in some such embodiments they are arranged in a repeating pattern along the lengthwise direction.

In some embodiments where the baffles are arranged in a repeating pattern, the repeating pattern consists of one of the first baffles, followed by one of the second baffles, followed by one of the third baffles, followed by one of the fourth baffles. Such a repeating pattern may include an even spacing between successive baffles, or it may include an uneven spacing. In some non-uniform spacing embodiments, a longitudinal spacing between the first and second flow baffles in the repeating pattern is greater than a longitudinal spacing between the second and third flow baffles in the repeating pattern. In some such embodiments, the distance between the first and second flow baffles is exactly twice the distance between the second and third flow baffles.

A repeating pattern with uneven spacing may still have some equal spacing between elements of the pattern. In some embodiments, in which the longitudinal distance between the first and second flow baffles of the repeating pattern is greater than the longitudinal distance between the second and third flow baffles of the repeating pattern, e.g. B. the distance in the longitudinal direction between the third and fourth flow baffles of the repeating pattern may be equal to the distance between the first and second flow baffles of the repeating pattern. Similarly, the longitudinal distance between the fourth baffle of one instance of the repeating pattern and the first baffle of an immediately following instance of the repeating pattern may be equal to the longitudinal distance between the second and third baffles of the repeating pattern.

In the embodiments in which the flow baffles are arranged in a repeating pattern with an uneven spacing, it may also be possible for the flow baffles with legs that extend into the same subset of the flow gaps, are evenly spaced from each other. The distance between successive one of the first and third flow baffles or the distance between successive one of the second and fourth flow baffles can be, for. B. be a constant distance. In some embodiments, a first constant distance between consecutive one of the first and third flow baffles may be equal to a second constant distance between consecutive one of the second and fourth flow baffles. In some such embodiments, the first baffles are spaced from the successive second baffles by an amount that is less than those first and second constant distances.

The legs of the flow baffles, which extend into the flow spaces, can guide the fluid so that it flows through these spaces in a sinusoidal pattern. The fluid in the flow spaces of the first subset is z. B. alternately directed so that it flows in opposite transverse directions (ie, from the first edge in the direction of the second edge and from the second edge in the direction of the first edge) by alternately on the legs of the one or more first flow baffles and meets the legs of the one or more third flow baffles. Similarly, the fluid in the flow spaces of the second subset is alternately directed so that it flows in opposite transverse directions by alternately striking the legs of the one or more second flow baffles and the legs of the one or more fourth flow baffles.

If those flow baffles having the legs extending into the same subset of the flow gaps are uniformly spaced from one another longitudinally at a constant distance, then the resulting sinusoidal flow pattern has a period equal to twice that constant distance .

In those cases in which the baffles whose legs extend into the first subset of the flow gaps (e.g. the first flow baffles and the third flow baffles) are offset in the longitudinal direction from the baffles whose legs extend into the second subset of the flow gaps (e.g. the second flow baffles and the fourth flow baffles), the resulting sinusoidal flow patterns in the first and second subsets are also offset. If these sinusoidal flow patterns have a completely identical period in the first and the second subset, then the offset leads to a phase shift of the sinusoidal flow patterns. The amount of phase shift can be expressed in degrees based on the fraction of the period that the offset represents, where a full period equals 360 degrees. In some exemplary embodiments, the phase shift is equal to 60 °, which means that the offset is one sixth of a period. In other embodiments, however, the phase shift can be less than or greater than 60 °.

If the plate pairs are spaced from one another by depressions that protrude outwardly from the plates, and these depressions are arranged in regularly spaced rows that extend in the transverse direction, then it may be advantageous to arrange the flow baffles along the longitudinal direction so that the legs of each baffle extend into the gaps between the rows of wells. In such embodiments, the spacing between the individual baffles is any integral multiple of the regular spacing between the rows of depressions.

Causing the fluid to flow in out-of-phase sinusoidal patterns in the first and second subsets of the flow gaps can result in increased heat transfer rates between the fluid flowing through the flow gaps and another fluid flowing within the plate pairs. This is particularly the case when the flow gaps of the first and second subset are arranged alternately along the stacking direction, so that each plate pair has one of the first subset of the flow gaps on one side of the plate pair and one of the second subset of the flow gaps on the opposite side of the plate pair having. The inventors have found that when the fluid hits a leg of the baffle blocking the flow channel and is directed to flow in the transverse direction, immediately upstream of the baffle in the longitudinal direction is an area of high velocity and consequently increased convective heat transfer occurs. After the fluid has flowed through the gap between the end of the leg and the wall of the housing and expands into the space between this flow baffle leg and the subsequent flow baffle leg in this flow channel, an area occurs conversely immediately downstream of the flow baffle in the longitudinal direction at low speed and consequently reduced convective heat transfer. In addition, the leg itself prevents the flow of fluid over that portion of the plate where it is located, thereby preventing any convective heat transfer from the surface of the plate on which the leg is located.

By staggering these convective heat transfer effects on one of the plate pairs along the longitudinal direction, a more uniform heat transfer rate can be achieved along the longitudinal direction.

Figure list

• 1 Fig. 3 is a perspective view of a plate heat exchanger in a housing according to an embodiment of the invention.
• 2 FIG. 13 is a partially exploded perspective view of a stack of plate pairs included in the plate heat exchanger according to FIG 1 is used.
• 3rd FIG. 13 is a partial sectional view of the plate heat exchanger of FIG 1 .
• 4th FIG. 13 is a perspective view of one embodiment of the plate heat exchanger of FIG
• 1 with the housing and other components removed to illustrate certain details of the heat exchanger.
• 5 is one along the lines VV to 4th cut view taken.
• 6th is the sectional view according to 5 , with certain components hidden for the sake of clarity.
• 7A and 7B are top views of the embodiment according to FIG 4th showing two different flow gaps between the plate pairs of the heat exchanger.
• 8th FIG. 13 is a top plan view of the embodiment of FIG 4th showing the flow paths for a fluid through the flow gaps according to the 7A and 7B illustrated.
• 9 FIG. 13 is a perspective view of another embodiment of the plate heat exchanger according to FIG 1 with the housing and other components removed to illustrate certain details of the heat exchanger.
• 10A and 10B are top views of the embodiment according to FIG 9 showing two different flow gaps between the plate pairs of the heat exchanger.
• 11 FIG. 13 is a top plan view of the embodiment of FIG 9 showing the flow paths for a fluid through the flow gaps according to the 10A and 10B illustrated.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it should be recognized that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. It should also be recognized that the phraseology and terminology used herein are for the purpose of description and should not be viewed as limiting. The use of “containing”, “comprising” or “having” and their variations is meant here to encompass both the items listed thereafter and their equivalents as well as additional items. Unless otherwise specified or restricted, the terms “attached,” “connected,” “supported” and “coupled” and their variations are used broadly and include both direct and indirect fastenings, connections, supports and couplings. Furthermore, “connected” and “coupled” are not limited to physical or mechanical connections or couplings.

A heat exchanger 1 in accordance with some embodiments of the invention, FIG 1 shown. The heat exchanger 1 is configured to divert heat between a first fluid flow passing through an inlet port 31 in the heat exchanger 1 enters and through an outlet opening 34 from the heat exchanger 1 exits, and a second fluid flow passing through an inlet port 32 in the heat exchanger 1 enters and through an outlet opening 33 from the heat exchanger 1 exits, to transfer.

The heat exchanger 1 can be particularly useful in exchanging heat between two fluid flows. For example, the first fluid flow can be a flow of a coolant, such as. B. water, ethylene glycol, propylene glycol or a glycol-water mixture. The second fluid flow can also, for example, be a flow of a lubricating oil or a hydraulic oil or a combustible fuel, such as. B. LNG or LPG. In some applications the heat exchanger 1 can be used to cool the second fluid by transferring heat from the second fluid to the first fluid as it passes through the heat exchanger 1 stream. In other applications the heat exchanger 1 can be used to heat the second fluid by transferring heat from the first fluid to the second fluid as they flow through the heat exchanger.

In some specific embodiments, the heat exchanger 1 used as a vaporizer for LNG or LPG. The LNG or LPG enters through the inlet port 32 in a liquid or a two-phase liquid-vapor state in the heat exchanger 1 and flows through the flow structures of the heat exchanger 1 while concurrent with a flow of liquid coolant into the heat exchanger 1 enters and through other flow structures of the heat exchanger 1 flows. As the two fluids flow through the heat exchanger, heat is convectively transferred from the higher temperature coolant to the lower temperature LNG or LPG. The transfer of heat into the LPG or LNG vaporizes the liquid portion of the LPG or the LNG, making it the heat exchanger 1 through the outlet opening 33 as a flow leaves completely in the vapor state. The coolant leaves the heat exchanger 1 with a reduced temperature through the outlet opening 34 .

As in 1 and 3rd shown includes the heat exchanger 1 an outer case 2 to contain the flow structures for the fluids. In the exemplary embodiment, the housing is 2 from multiple walls, especially the walls 7-13 , which are connected together to form a volume of fluid 4th to be defined so that the first fluid flows therethrough. The case 2 can be made of a metal such as B. aluminum or steel. However, it should be recognized that the case 2 need not be constructed of metal and in some cases at least partially of other materials, such as e.g. B. plastic, can be constructed. In at least some embodiments, the housing can be provided as part of another component. The case 2 can e.g. B. be provided as a cavity or an oil pan in an engine block.

The connections 32 and 33 extend through openings in a top wall 10 of the housing 2 thereby enabling fluid lines to be connected to the second fluid in and out of the heat exchanger 1 to transport. It should be recognized, however, that one or both of the ports for this fluid may alternatively be on other walls of the housing 2 can be arranged. The connection 31 extends through the wall 12th of the housing 2 while connecting 34 through the wall 13th of the housing 2 extends, but it should again be recognized that one or both of these connections alternatively on other walls of the housing 2 can be arranged. The arrangement of the connections 31-34 as shown in the exemplary embodiment can provide increased heat exchanger efficiency by providing an overall countercurrent orientation between the two fluid flows. In some cases, however, it may be advantageous to rearrange the connections, e.g. B. to achieve an orientation of a concurrent flow or a parallel flow.

Inside the case 2 of the heat exchanger 1 is a pile 3rd of pairs of plates 5 arranged, the in the partial exploded view after 2 is shown that is within the internal fluid volume 4th of the housing 2 is housed, as in the partially cut-away view of FIG 3rd is shown. The pairs of plates 5 are in a stacking direction indicated by the arrow 22nd is specified, stacked together to make the stack 3rd to build. Such a heat exchanger assembly, referred to herein as a plate heat exchanger assembly, allows the flow of the second fluid through the interior of the plate pairs 5 flows while the flow of the first fluid through the fluid volume 4th flows. This flow of the first fluid flows through the flow gaps 6th which, as will be described, between adjacent plate pairs of the plate pairs 5 are arranged so that the first fluid over the outer surfaces of the plate pairs 5 flows to exchange heat with the second fluid, while this second fluid flows through the plate pairs 5 flows.

Each of the pairs of plates 5 extends in a longitudinal direction indicated by the arrow 20th is specified. The total flow of both the first fluid and the second fluid are preferably aligned in the longitudinal direction and are preferably arranged to be in a countercurrent orientation to one another in order to maximize the heat exchange efficiency. For this purpose, the longitudinal direction 20th preferably greater than the transverse direction of the pairs of plates 5 (the one by the arrow 21 is specified) that corresponds to this longitudinal direction 20th is perpendicular.

To get the second fluid in and out of the pairs of plates 5 To transport, an inlet manifold extends 35 at a first end of the stack 3rd in the longitudinal direction 20th in the stacking direction 22nd through the pile 3rd and extends an outlet manifold similarly 36 at a second end of the stack 3rd lengthways through the stack 3rd . The distributors 35 and 36 can at least partially z. B. be defined by flanged openings in the plates of the plate pairs 5 are trained. In the flow gaps 6th between adjacent pairs of plates 5 can ring-shaped spacer rings at the distribution points 37 be arranged to further define the manifolds. The inlet fitting 32 is on the inlet manifold 35 aligned to the flow of the second fluid into the manifold 35 to feed this flow between the different pairs of plates 5 of the stack 3rd while distributing the outlet fitting to the outlet manifold 36 is aligned to the flow from the manifold 36 after removing them from the various pairs of plates 5 in this mailing list 36 has been drained.

Several baffles 7th , in the 3rd generally shown are attached to the stack 3rd mounted to the first fluid through the flow gap 6th to conduct so that the heat transfer rate between the fluids can be increased. The baffles 7th each contain the legs 17th (in the 6th are best seen), each of which is in one of the flow gaps 6th extends between the plates that form this flow gap 6th limit the direct passage of the first fluid at this point along the longitudinal direction 20th to block.

The baffles 7th are comb-like baffles with a backbone 39 from which the thighs 17th extend. The backbone 39 extends in the stacking direction 22nd of the stack 3rd alongside one of the longitudinal edges of the pairs of plates 5 and is preferably on the adjacent wall of the housing 2 arranged to block any of the fluid from the baffle 7th between the pile 3rd and the case 2 bypasses. In order to enable improved blocking of a bypass flow in the case where the housing walls are not uniform, the backbones can 39 be provided with sealing lips that adapt to the housing walls.

The thigh 17th extend from one of the longitudinal edges of the pairs of plates 5 in the transverse direction 21 into the flow gap 6th . Preferably the legs extend 17th over a distance that is more than half the total dimension of the pairs of plates 5 in the transverse direction but less than the full extent of this overall dimension. A final end 18th every thigh 17th is thereby spaced from the longitudinal edge of the pair of plates, which is opposite the longitudinal edge from which the leg extends. The closing ends 18th those thighs 17th extending from a first longitudinal edge 15th of the plate pairs extend (e.g. the legs of the baffles 7a and 7d as in the 7A and 7B shown) are e.g. B. from a second longitudinal edge 16 spaced while the terminating ends 18th those thighs 17th that extends from the second longitudinal edge 16 of the plate pairs extend (e.g. the legs of the baffles 7b and 7c as in the 7A and 7B shown), from the first longitudinal edge 15th are spaced. As a result of these clearances, the fluid can pass between these termination ends 18th and a corresponding wall 8th or 9 of the housing 2 flow so that the first fluid continues in the longitudinal direction 20th can flow.

As in the 5 and 6th can be seen, each of the baffles has 7th the thigh 17th on, which is in some, but not all, of the flow gaps 6th extend. The flow gap 6th are in a first subset 6a the flow gap and a second subset 6b the flow gap separated. The flow gaps are preferably of the first subset 6a and the flow gaps of the second subset 6b along the stacking direction 22nd arranged alternately, as in 5 is shown. Each of the baffles 7th shows the thighs 17th which extend into a subset of the flow gaps, but not into the other of the subsets. Specifically in the 7A and 7B extend z. B. the legs of the flow baffles 7a and 7c into the flow gap of the first subset 6a , but not in the flow gap of the second subset 6b , while the legs of the flow baffles 7b and 7d into the flow gap of the second subset 6b , but not in the flow gap of the first subset 6a extend. Each of the flow baffles can have the notches 38 be provided that allow the edges of the plate pairs in the baffle 7th be added to the flow baffles 7th assemble properly.

In addition to the thighs 17th that are in the flow crevice 6th between adjacent pairs of plates 5 extend are the baffles 7th also with an additional leg 17th provided, which is in a similar flow gap between one terminal of the plate pairs 5 and an adjacent wall of the housing 2 is arranged. The flow baffles 7a and 7c have such an additional leg 17th on, which is in a flow gap between the end plate pair 5 at a first end 23 of the stack and an adjacent wall 10 of the housing 2 extends while the flow baffles 7b and 7d such an additional leg 17th have, which is in a flow gap between the end plate pair 5 at a second end 24 of the stack and an adjacent wall 11 of the housing 2 extends.

The flow baffles can be arranged in a pattern along the lengthwise direction 20th be arranged so that a sinusoidal flow pattern of the first fluid is developed through the flow gaps. The sinusoidal pattern developed in the first subset of the flow gaps can be independent of the sinusoidal pattern developed in the second subset. 8th sets the path of the fluid through the flow gaps of the first subset 6a with the meandering solid arrow 29 and the path of the fluid through the flow gaps of the second subset 6b with the meandering dashed arrow 30th represent.

The sinusoidal flow path 29 arises from a repeating pattern through which the baffles 7a and 7c along the longitudinal direction 20th are arranged. As in 7A shown are the flow baffles 7a and 7c (ie, the flow baffles 7th with the thighs that are into the first subset of the flow paths 6a extend) alternately at a regular interval along the longitudinal direction 20th arranged. A flow baffle 7a a flow baffle follows 7c that at a further distance along the longitudinal direction 20th is spaced, followed by another flow baffle 7a which is spaced some further distance along again. This pattern can be found along the length of the plate pairs in the longitudinal direction 20th repeat additional times, but (as in the embodiment according to 4th can be seen) does not have to repeat. The period of the sinusoidal flow pattern is determined by the distance between successive occurrences of the same flow baffle (e.g. the flow baffle 7a ) certainly. It should be noted that while the exemplary embodiment according to FIGS 4-8 shows a constant spacing between the flow baffles of a given subset of the flow gaps, in some alternative embodiments a non-constant spacing may be used, in which case the sinusoidal flow path has a non-constant period.

In a manner similar to that in 7B is shown, the flow baffles 7b and 7d (ie, the flow baffles 7th with the legs, which are in the second subset of the flow paths 6b extend) alternately at a regular interval along the longitudinal direction 20th arranged around the sinusoidal flow path 30th to generate within this flow gap. In the exemplary embodiment according to 4-8 are the baffles 7b along the longitudinal direction 20th on the baffles 7a aligned with the baffles 7d similar to the baffles 7c are aligned. As a result, the flow paths are sinusoidal 29 and 30th both have the same period, being about 180 ° out of phase with one another.

9 Figure 3 illustrates an alternate embodiment of a disk pack 3 ' represents the inside of the heat exchanger 1 can be used. The plate pack is using the same plate pairs 5 like the pile 3rd constructed, but has a different arrangement of the comb-like baffles 7th on. As in the 10A and 10B shown, the stack has 3 ' also the flow baffles 7a and 7c that have the legs that extend into the flow gaps of a first subset 6a ' extend, and the flow baffles 7b and 7d that have the legs that extend into the flow gaps of a second subset 6b ' extend on. The baffles 7a and 7c are in turn arranged alternately along the longitudinal direction at a constant distance and extend from the opposite longitudinal edges 15th or. 16 into the flow gap. Likewise are the baffles 7b and 7d again arranged alternately along the longitudinal direction at a constant distance, whereby they differ from the opposite longitudinal edges 16 or. 15th extend into the flow gaps. The sinusoidal flow patterns become accordingly 29 ' and 30 ' within the subsets 6a ' or. 6b ' generated as in 11 is shown.

In contrast to the embodiment according to 4th however, the flow baffles with the legs, which are in the second subset 6b ' extend in the longitudinal direction of the flow baffles with the legs extending into the first subset 6a ' extend, staggered, resulting in a phase shift between the flow patterns 29 ' and 30 ' leads that is smaller than 180 °.

In the embodiment according to 9 are the flow baffles 7th arranged in a fully staggered, repeating pattern, with a first flow baffle along the longitudinal direction 7a a second flow baffle 7b follows, followed by a third flow baffle 7c , followed by a fourth baffle 7d , followed again by another instance of this pattern. In the 10A and 10B can also be seen that the distance in the longitudinal direction between a baffle 7a and the following baffle 7b greater than the distance between this baffle 7b and the following baffle 7c is. Furthermore, there is the distance between a baffle 7c and the following baffle 7d the same as the distance between a baffle 7a and the following baffle 7b , being the distance between a baffle 7d and the following baffle 7a the same as the distance between a baffle 7b and the following baffle 7c is. This spacing pattern has the result that the phase shift between the flow patterns 29 ' and 30 ' is less than 90 °. In the case where all the distances are equal, the phase shift would be 90 °.

The flow gap 6th between adjacent pairs of plates 5 can through a pattern of outwardly facing depressions 14th formed in the plates. These depressions 14th are arranged in a regularly repeating arrangement and are further arranged so that the locations of the wells are on adjacent pairs of plates 5 match each other so that the plate pairs 5 (e.g., by brazing) can be joined together to form the finished stack 3rd or 3 ' with the required flow gaps 6th to build. The thigh 17th the comb-like flow baffles 7th may be dimensioned to have a height generally equal to twice the height of the indentations 14th (with a little play for the Manufacturing tolerances) is so that the legs 17th the gap between the pairs of plates 5 can fill to block the flow of the first fluid.

The pattern of the pits 14th is such that the indentations 14th arranged in rows that extend in the transverse direction 21 extend with the rows longitudinally 20th are spaced apart to provide the spaces for the legs 17th the flow baffles 7th to accomplish. The distance between the flow baffles 7th can then be expressed as an integral multiple of the distance between the transverse rows of the wells 14th be expressed. In the exemplary embodiment according to 9 are the period of the sinusoidal flow path 29 ' (which is equal to the distance between successive ones of the first flow baffles 7a is) and the period of the sinusoidal flow path 30th (which is equal to the distance between successive ones of the second flow baffles 7b is) both equal to six pitches of the rows of wells, as from the 10A and 10B can be seen. Each distance between the rows of depressions is therefore equal to a 60 ° section of the sinusoidal path.

When those baffles 7th whose legs extend from the same longitudinal edge of the pairs of plates 5 extend (e.g. the flow baffles 7b and 7c ), were aligned in pairs along the longitudinal direction, then the phase shift between the sinusoidal flow patterns would be zero. Consequently, the phase shift can be caused by the offset between the baffle 7b and the baffle 7c an instance of the repeating pattern or by the offset between the baffle 7d an instance and the baffle 7a of the following instance. In the exemplary embodiment according to 9 this offset is equal to a single pitch of the rows of pits, which is equivalent to a phase shift of 60 °.

By causing the first fluid to flow through the flow gaps in a sinusoidal pattern 6th to flow, the heat transfer capacity of the heat exchanger 1 improved. This is due, at least in part, to higher Reynolds numbers in the fluid flow immediately upstream of each baffle 7th attributed to where the flow of fluid from the longitudinal direction 20th to the cross direction 21 is directed. The inventors have found that once the fluid has passed through the gap between the end 18th the legs of the flow baffles and the opposite wall of the housing 2 flows to longitudinally 20th going further, a "dead zone" of low Reynolds number is formed immediately downstream of the baffle. The rate of convective heat transfer is consequently reduced in this area immediately downstream. While such an undesirable decrease in local heat transfer efficiency can be partially remedied by increasing the number of baffles and decreasing the spacing therebetween, such a modification would increase the pressure drop through the heat exchanger, which is often undesirable.

By moving the baffles in adjacent flow gaps 6th the zones of low convective heat transfer on an outward-facing surface of each pair of plates 5 be aligned with the high convective heat transfer zones on the other outward facing surface of the pair. This allows for a more uniform rate of heat transfer that is higher than would be achieved without the baffles.

In some applications, the increased rate of heat transfer resulting from the described baffle assemblies may only be necessary over a portion of each plate pair. It can e.g. For example, it may be desirable to have the increased heat transfer rate only at one end of the stack 3rd in the longitudinal direction 20th (ie, near the inlet port 31 or the outlet connection 32 ) to create an improved heat transfer in one area of the heat exchanger 1 which would otherwise have limited heat transfer efficiency due to a reduced approach temperature difference between the two fluids in this area.

The heat exchanger 1 can find particular use as a vaporizer for LNG or LPG. In such an application, the LNG or LPG would be the fluid that is directed to flow through the pairs of plates 5 to flow while a liquid coolant through the flow gaps 6th flows to transfer heat to the LNG or LPG and thereby vaporize the fluid. The LNG or LPG enters the heat exchanger at a very low temperature 1 one what a risk of freezing of the liquid coolant near the inlet port 32 of LNG or LPG. By providing the baffles described, especially in this area, the risk of freezing can be reduced.

While the thighs 17th as shown in the exemplary embodiments, perpendicular to the longitudinally extending edges 15th and 16 of the plate pairs 5 can extend the thighs 17th alternatively in a non-perpendicular manner in the transverse direction 21 extend. It can e.g. B. observed that the depressions 14th in addition to being arranged in rows running in the transverse direction 21 run, are also arranged in rows at an angle of about 45 ° to both the transverse direction 21 as well as to the longitudinal direction 20th run away. In some applications it may be desirable to have the thighs 17th the baffles 7th extend into the flow gaps along such an angle. In such an embodiment, the legs would 17th still in the flow gap 6th extend to create a sinusoidal flow pattern as they are still extending in the transverse direction from one of the edges 15th , 16 would extend. Furthermore, the pattern of the pits can be adjusted to create the rows of pits at angles other than 45 °.

Various alternatives to certain features and elements of the present invention are described with respect to specific embodiments of the present invention. Except for features, elements, and operations that are mutually exclusive or inconsistent with any embodiment described above, it should be stated that the alternative features, elements, and operations described with respect to a particular embodiment are applicable to the other embodiments .

The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation on the concepts and principles of the present invention. As such, it will be recognized by one of ordinary skill in the art that various changes in the elements and their configuration and arrangement can be made without departing from the spirit and scope of the present invention.

Claims (16)

Plate heat exchanger, which includes: a housing defining a volume for fluid to flow therethrough; a stack of plate pairs disposed within the housing, each plate pair having a longitudinal direction and a transverse direction, the dimension of the plate pairs in the longitudinal direction being greater than the dimension of the plate pairs in the transverse direction; a plurality of flow gaps which are arranged between adjacent ones of the plate pairs in a stacking direction of the stack and between the outermost of the plate pairs and the walls of the housing, the plurality of flow gaps consisting of a first subset of the plurality of flow gaps and a second subset of the plurality of flow gaps, the flow gaps the first subset and the flow gaps of the second subset are arranged alternately in the stacking direction; and a plurality of comb-like baffles extending into the plurality of flow gaps to define a sinusoidal flow path for the fluid that extends longitudinally within each of the flow gaps, the sinusoidal flow paths in the flow gaps of the second subset of the sinusoidal flow paths in the flow gaps of the first subset are out of phase. Plate heat exchanger according to Claim 1 , whereby the sinusoidal flow paths in the flow gaps of the second subset are out of phase with the sinusoidal flow paths in the flow gaps of the first subset by no more than 90 ° or the sinusoidal flow paths in the flow gaps of the second subset are shifted from the sinusoidal flow paths in the flow gaps of the first subset Are 60 ° out of phase. Plate heat exchanger according to Claim 1 or 2 , wherein the plate pairs are provided with an arrangement of outwardly directed depressions, adjacent ones of the plate pairs being connected to one another by the depressions, the depressions being arranged in rows extending in the transverse direction, and the comb-like baffles between the rows of Wells are arranged. Plate heat exchanger according to Claim 1 wherein the plurality of comb-like baffles are arranged in a repeating pattern along the longitudinal direction. Plate heat exchanger according to Claim 4 wherein one instance of the repeating pattern consists of four of the comb-like baffles. Plate heat exchanger according to Claim 4 or 5 wherein the repeating pattern includes a first comb-like baffle extending from a first longitudinal edge of each plate pair, followed by a second comb-like baffle extending from a second longitudinal edge of each plate pair, followed by a third comb-like baffle extending from the second longitudinal edge of each plate pair extends, followed by a fourth comb-like baffle which extends from the first longitudinal edge of each plate pair. Plate heat exchanger according to Claim 6 , wherein a distance in the longitudinal direction between the first comb-like baffle and the second comb-like baffle is greater than a distance in the longitudinal direction between the second comb-like baffle and the third comb-like baffle. A plate heat exchanger comprising: a housing defining a volume for fluid to flow therethrough; a stack of plate pairs disposed within the housing, each plate pair having a longitudinal direction and a transverse direction, the dimension of the plate pairs in the longitudinal direction being greater than the dimension of the plate pairs in the transverse direction, with adjacent ones of the plate pairs being spaced apart by several Defining flow gaps between the pairs of plates for fluid to flow therethrough, each of the pairs of plates having a first edge and a second edge both of which extend in the longitudinal direction; one or more first flow baffles disposed within the housing, each of the one or more first flow baffles having a plurality of legs extending in the transverse direction from the first edges of the plate pairs into a first subset of the plurality of flow gaps, but not into a second A subset of the plurality of flow gaps extend, the plurality of legs extending more than half the dimension of the plate pairs in the transverse direction, the terminal ends of the plurality of legs being spaced from the second edges of the plate pairs to allow the fluid to pass between the terminal ends and to flow a wall of the housing adjacent the second edges; one or more second flow baffles disposed within the housing, each of the one or more second flow baffles having a plurality of legs extending in the transverse direction from the second edges of the plate pairs into the second subset of the flow gaps, but not into the first subset of the flow gaps, the plurality of legs extending more than half the dimension of the pairs of plates in the transverse direction, the terminal ends of the plurality of legs being spaced from the first edges of the pairs of plates to allow the fluid to pass between the terminal ends and a wall the housing adjacent the first edges flows; one or more third flow baffles disposed within the housing, each of the one or more third flow baffles having a plurality of legs extending in the transverse direction from the second edges of the plate pairs into the first subset of the flow gaps, but not into the second subset of the flow gaps, the plurality of legs extending more than half the dimension of the pairs of plates in the transverse direction, the terminal ends of the plurality of legs being spaced from the first edges of the pairs of plates to allow the fluid to pass between the terminal ends and a wall the housing adjacent the first edges flows; and one or more fourth flow baffles disposed within the housing, each of the one or more fourth flow baffles having a plurality of legs extending in the transverse direction from the first edges of the plate pairs into the second subset of the flow gaps but not into the first Subset of the flow gaps extend, the plurality of legs extending more than half the dimension of the plate pairs in the transverse direction, the terminal ends of the plurality of legs being spaced from the second edges of the plate pairs to allow the fluid between the terminal ends and a Wall of the housing, which is adjacent to the second edges, flows. Plate heat exchanger according to Claim 8 , wherein the flow gaps of the first subset and the flow gaps of the second subset are arranged alternately in a stacking direction of the stack. Plate heat exchanger according to Claim 8 or 9 wherein the housing includes a wall spaced from a terminal one of the pairs of plates at a first end of the stack in the stacking direction to define a flow gap for the fluid to flow therethrough, and wherein each of the one or more first flow baffles and each of the one or more third flow baffles have an additional long leg which extends in the transverse direction into this flow gap; and / or the housing includes a wall spaced from a terminal one of the pairs of plates at a second end of the stack in the stacking direction opposite the first end to define a flow gap for the fluid to flow therethrough, and wherein each of the one or more second flow guide plates and each of the one or more fourth flow guide plates has an additional long leg which extends in the transverse direction into this flow gap. Plate heat exchanger according to Claim 8 , 9 or 10 wherein each of the one or more first flow baffles is aligned with one of the one or more second baffles in the longitudinal direction, and wherein each of the one or more third flow baffles is aligned with one of the one or more fourth baffles in the longitudinal direction. Plate heat exchanger after one of the Claims 8 - 11 wherein the first, second, third and fourth flow baffles are all offset along the longitudinal direction; and / or the first, second, third and fourth flow baffles in are arranged in a repeating pattern along the lengthwise direction Plate heat exchanger according to Claim 12 wherein the repeating pattern consists of one of the first flow baffles followed by one of the second flow baffles followed by one of the third flow baffles followed by one of the fourth flow baffles. Plate heat exchanger according to Claim 13 wherein a distance in the longitudinal direction between the first and second flow baffles of the repetitive pattern is greater than a distance in the longitudinal direction between the second and third flow baffles of the repetitive pattern; and / or the distance in the longitudinal direction between the first and second flow baffles of the repeating pattern is exactly twice the distance in the longitudinal direction between the second and third flow baffles of the repeating pattern. Plate heat exchanger according to Claim 14 wherein a distance in the longitudinal direction between the third and fourth flow baffles of the repeating pattern is equal to the distance in the longitudinal direction between the first and second flow baffles of the repeating pattern. Plate heat exchanger according to Claim 14 , wherein a distance in the longitudinal direction between the fourth flow baffle of one instance of the repetitive pattern and the first flow baffle of an immediately following instance of the repetitive pattern is equal to the distance in the longitudinal direction between the second and third flow baffles of the repetitive pattern.

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