Heat exchanger assembly and use of an apparatus in a heat exchanger

Abstract

A heat exchanger assembly comprises a heat exchanger for heat exchange between at least a first heat exchange fluid and a second heat exchange fluid. The heat exchanger comprises at least one heat transfer element delimiting a first fluid path from a second fluid path, and a through connection for the first heat exchange fluid arranged at a first side portion of an outer structure of the heat exchanger. The assembly comprises a pressure pulse damping apparatus comprising an elastic element, and a first conduit leading to the elastic element. The first conduit comprises a first opening connected to the through connection of the heat exchanger such that the first conduit is fluidly connected with the first fluid path. The elastic element fluidly communicates with the first fluid path only via the first opening. There is further disclosed use of a pressure pulse damping apparatus comprising an elastic element.

Claims

1. A heat exchanger assembly comprising: a plate heat exchanger for heat exchange between at least a first heat exchange fluid and a second heat exchange fluid, the plate heat exchanger comprising a plurality of heat transfer plates arranged between an inside of a pressure plate and an inside of a frame plate and delimiting a first fluid path for the first heat exchange fluid from a second fluid path for the second heat exchange fluid inside the plate heat exchanger, the first fluid path being defined between some pairs of adjacent ones of the heat transfer plates, the second fluid path being defined between other pairs of adjacent ones of the heat transfer plates, the plate heat exchanger also comprising a through connection in one of the frame plate and the pressure plate for the first heat exchange fluid, which through connection extends from the inside to an outside of said one of the frame plate and the pressure plate; a pressure pulse damping apparatus comprising an elastic element, and a first conduit leading to the elastic element; the first conduit comprising a first opening connected to the through connection of the plate heat exchanger such that the first conduit is in fluid connection with the first fluid path; the elastic element being in fluid communication with the first fluid path only via the first opening; the other one of the frame plate and the pressure plate comprising an inlet for the first heat exchange fluid to the plate heat exchanger; a portion of the first fluid path being a straight fluid path extending from the inlet for the first heat exchange fluid, through the heat transfer plates, and to the through connection; and the pressure pulse damping apparatus being arranged after the straight fluid path in a flow direction wherein the first heat exchange fluid must flow along the straight fluid path and through said one of the frame plate and the pressure plate via the through connection to reach the pressure pulse damping apparatus.

2. The assembly according to claim 1, wherein the elastic element comprises a movable partition, the movable partition being adapted in use to be subjected to a pressure pulse in the first heat exchange fluid.

3. The assembly according to claim 1, wherein the elastic element comprises a chamber which is at least partially filled with a gas, the chamber and the first conduit forming a closed compartment.

4. The assembly according to claim 3, wherein the gas inside the chamber is delimited by the movable partition such that in use the pressure pulse in the first heat exchange fluid is transferred via the movable partition to the gas inside the chamber.

5. The assembly according to claim 2, wherein the movable partition comprises a membrane or a piston.

6. The assembly according to claim 2, wherein the elastic element comprises a spring, the spring abutting the movable partition.

7. Use of a pressure pulse damping apparatus comprising connecting the pressure pulse damping apparatus, which comprises an elastic element and a first conduit leading to the elastic element, to a heat exchanger for damping pressure pulses in the heat exchanger, the heat exchanger comprising a plurality of heat transfer plates arranged between an inside of a pressure plate and an inside of a frame plate and delimiting a first fluid path for a first heat exchange fluid from a second fluid path for a second heat exchange fluid inside the heat exchanger, wherein the first conduit comprises a first opening connected to the heat exchanger such that the first conduit is in fluid connection with the first fluid path of the heat exchanger, the heat exchanger also comprising a through connection in one of the frame plate and the pressure plate for the first heat exchange fluid, which through connection extends from the inside to an outside of said one of the frame plate and the pressure plate, the other one of the frame plate and the pressure plate comprising an inlet for the first heat exchange fluid to the heat exchanger, a portion of the first fluid path being a straight fluid path extending from the inlet to the through connection so that the first heat exchange fluid flows along the straight fluid path from the inlet to the through connection during operation of the heat exchanger, the pressure pulse damping apparatus being connected to the heat exchanger such that the elastic element is in fluid communication with the first fluid path only via the first opening, and the pressure pulse damping apparatus being arranged after the straight fluid path in a flow direction wherein the first heat exchange fluid must flow along the straight fluid path and through said one of the frame plate and the pressure plate via the through connection to reach the pressure pulse damping apparatus.

8. The use of the pressure pulse damping apparatus according to claim 7, wherein the elastic element comprises a movable partition, the movable partition being adapted in use to be subjected to a pressure pulse in the first heat exchange fluid.

9. The use of the pressure pulse damping apparatus according to claim 7, wherein the elastic element comprises a chamber which is at least partially filled with a gas, the chamber and the first conduit forming a closed compartment.

10. The use of the pressure pulse damping apparatus according to claim 9, wherein the gas inside the chamber is delimited by the movable partition such that in use the pressure pulse in the first heat exchange fluid is transferred via the movable partition to the gas inside the chamber.

11. The use of the pressure pulse damping apparatus according to claim 8, wherein the elastic element comprises a spring, the spring abutting the movable partition.

12. The use of the pressure pulse damping apparatus according to claim 7, wherein the first side portion of the heat exchanger is formed by a pressure plate or a frame plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying drawings, in which:

(2) FIGS. 1-5 illustrate heat exchanger assemblies according to embodiments comprising a heat exchanger and a pressure pulse damping apparatus. FIGS. 1-5 also illustrate embodiments of use of pressure pulse damping apparatuses for damping pressure pulses in heat exchangers.

(3) FIG. 6 illustrates a portion of a pressure pulse damping apparatus according to example embodiments.

DETAILED DESCRIPTION

(4) The present invention will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Disclosed features of example embodiments may be combined as readily understood by one of ordinary skill in the art to which this invention belongs. Like numbers refer to like elements throughout.

(5) Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

(6) FIG. 1 illustrates a heat exchanger assembly 2 according to embodiments comprising a heat exchanger 4 and a pressure pulse damping apparatus 6. FIG. 1 also illustrates embodiments of use of a pressure pulse damping apparatus 6 for damping pressure pulses in the heat exchanger 4. The pressure pulse damping apparatus 6 is shown partially in cross section. As well known in the technical field of heat exchangers, the plate heat exchanger 4 is provided with a plate package 8 of heat exchange plates 10 clamped between a frame plate 9 and a pressure plate 11. The pressure plate 11 may be seen as a first side portion of the heat exchanger 4 and the frame plate 9 may be seen as a second side portion of the heat exchanger 4. The heat exchange plates 10 are utilized for exchange of heat between a first and a second heat exchange fluid. The plates 10 form plate interspaces adapted to be flowed through by the heat exchange fluids. The plates 10 are provided with four port holes which form inlet and outlet channels 12, 14 (two of which are indicated by broken lines in FIG. 1) extending through the plate package 8 and communicating with the plate interspaces. In use, a first heat exchange fluid flows through an inlet conduit 16 into the inlet channel 12, through every second plate interspace of the plate package 8 to the outlet channel 14, and out of the heat exchanger 4 to an outlet conduit 18.

(7) The pressure plate 11 forms the first side portion of the plate heat exchanger 4 and is provided with a through connection 20 forming an extension of the inlet channel 12. The pressure pulse damping apparatus 6 is connected to the pressure plate 11 such that a first conduit 22 of the pressure pulse damping apparatus 6 is in fluid communication with the inlet channel 12 via the through connection 20. Accordingly, in use the first conduit 22 is filled with the first heat exchange fluid. The pressure pulse damping apparatus 4 comprises a chamber 24 which is filled with a gas such as air. The chamber 24 is closed and a movable partition in the form of a membrane 26 at least partially encloses the gas, and delimits the gas from the first heat exchange fluid. The membrane 26 and the gas in the chamber 24 form an elastic element.

(8) Frame plates 9 and pressure plates 11 are frequently manufactured with through holes in positions where the inlet and outlet channels in the plate package 8 are arranged. Through holes which are not required in use are closed by covers. Thus, the through connection 20 may be readily available for forming a fluid connection between the first conduit 22 and the inlet channel 12. Inlet and outlet channels 12, 14 for the heat exchange fluids communicate with the inlet and outlet conduits 16, 18 via to the through holes in the frame plate 9.

(9) When in use of a heat exchanger 4 with a first heat exchange fluid, primarily being in liquid form, a pressure pulse arrives with the first heat exchange fluid to the heat exchanger 4, the pressure pulse will travel along the inlet channel 12 into the first conduit 22 of the pressure pulse damping apparatus 6. When the pressure pulse arrives at the membrane 26 the gas on the other side of the membrane 26 is compressed by the pressure pulse. Similarly, when a gas slug enters the inlet channel 12 and is followed by liquid at high speed, a pressure pulse is formed when the liquid impacts against the membrane 26.

(10) The pressure pulse will be transmitted to the gas in the chamber 26 and since the gas is compressible, the pressure pulse will be damped. Furthermore, the speed of the pressure pulse will decrease as it gradually compresses the gas. Accordingly, if the pressure pulse is not absorbed by the gas the pressure pulse transmitted from the gas back to the first heat exchange fluid will have lower amplitude and be distributed over a longer time than the original pressure pulse. The pressure pulse affecting the heat exchanger 4 will thus be of a kind which is more easily withstood by the heat exchanger 4 and its plate package 8, seen in contrast with a pressure pulse impacting, or forming, on an inside of the pressure plate 11 and being transmitted through the plate package 8 towards the outlet conduit 18.

(11) The first conduit 22 comprises a first opening connected to the through connection 20. A flange 28 is arranged circumferentially around the first conduit 22 at the first opening for connecting the pressure pulse damping apparatus 6 to the pressure plate 11. The flange 28 may be provided with through holes such that it may be attached to the heat exchanger 4 by means of screws, or nuts and bolts. Thus, the pressure pulse damping apparatus 6 may easily be attached retroactively in an already present installation if it is revealed that the installation is troubled by pressure pulses. Such retroactive installation may also be performed in a flammable environment since no welding is necessary. The pressure pulse damping apparatus 6 may comprise a lid 30, through which the first conduit 22 of the pressure pulse damping apparatus 6 and the inlet channel 12 of the plate heat exchanger 4 are accessible. A filter (also called port strainer) may be positioned in the inlet channel 12 via the lid 30. When the heat exchanger 4 is in use, the lid 30 is maintained closed.

(12) FIG. 2 illustrates a heat exchanger assembly 2 according to embodiments comprising a heat exchanger 4 and a pressure pulse damping apparatus 6. FIG. 2 also illustrates embodiments of use of a pressure pulse damping apparatus 6 for damping pressure pulses in the heat exchanger 4. The pressure pulse damping apparatus 6 is shown partially in cross section. The pressure pulse damping apparatus 6 comprises a first conduit 22 connected to a pressure plate 11 of the heat exchanger 4, and an elastic element comprising a piston 40 and a spring 42. Again, the first conduit 22 communicates with an inlet channel for a first heat exchange fluid in the heat exchanger 4. The piston 40 is a movable partition, in use delimiting inter alia a chamber 44 and the spring 42 from the first heat exchange fluid in the first conduit 22. The piston 40 is movable along inner walls of the chamber 44, which has a uniform inner diameter. The spring 42 is arranged in the chamber 44 and abuts against the piston 40 and an end wall 46 of the chamber 44. The end wall 46 is provided with a through hole for a rod 48 attached to the piston 40 to pass through. When a pressure pulse in the first heat exchange fluid via the first conduit 22 impacts against the piston 40, the spring 42 is compressed and the piston 40 is moved into the chamber 44. Thus, the pressure pulse is damped and at least partially absorbed.

(13) A further damping effect may be achieved by air inside the chamber 44, which is forced through the through hole in the end wall 46 as the piston is moved into the chamber 44. As the spring 42 again expands, the movement of the piston 40 is damped by air being admitted into the chamber 44 only at a limited rate through the through hole in the end wall 46. In this manner the pressure pulse may be further damped since any pressure pulse being reflected back into the first heat exchange fluid by the spring 42 and the piston 40 is restricted.

(14) FIG. 3 illustrates the assembly 2 of FIG. 2 when the piston 40 and the spring 42 has been affected by a pressure pulse in the first heat exchange fluid. The spring 42 has thus, been compressed. The rod 48 extends through the through hole in the end wall 46 of the chamber 44.

(15) FIG. 4 illustrates a heat exchanger assembly 2 according to embodiments comprising a heat exchanger 4 and a pressure pulse damping apparatus 6. FIG. 4 also illustrates embodiments of use of a pressure pulse damping apparatus 6 for damping pressure pulses in the heat exchanger 4. The pressure pulse damping apparatus 6 is shown partially in cross section. The pressure pulse damping apparatus 6 comprises a first conduit 22 connected to a pressure plate 11 of the heat exchanger 4. Again, the first conduit 22 communicates with an inlet channel for a first heat exchange fluid in the heat exchanger 4. The pressure pulse damping apparatus 6 further comprises an elastic element comprising a piston 40, a spring 42, and a chamber 24. The piston 40 is a movable partition, in use delimiting inter alia the chamber 24 and the spring 42 from the first heat exchange fluid in the first conduit 22. The piston 40 is movable along inner walls of the chamber 24, which has a uniform inner diameter. The spring 42 is arranged in the chamber 24 and abuts against the piston 40 and an end wall 46 of the chamber 24. The chamber 24 is filled with a gas such as air and closed by means of the piston 40, which delimits the gas from the first heat exchange fluid. The piston 40, the spring 42, and the gas in the chamber 24 form an elastic element.

(16) In the embodiments according to FIG. 4, the spring 42 and the gas enclosed in the chamber 24 cooperate to damp pressure pulses in the first heat exchange fluid.

(17) FIG. 5 illustrates a heat exchanger assembly 2 according to embodiments comprising a heat exchanger 4 and a pressure pulse damping apparatus 6. FIG. 5 also illustrates embodiments of use of a pressure pulse damping apparatus 6 for damping pressure pulses in the heat exchanger 4. The pressure pulse damping apparatus 6 is shown partially in cross section. The pressure pulse damping apparatus 6 comprises a first conduit 22 connected to a pressure plate 11 of the heat exchanger 4. Again, the first conduit 22 communicates with an inlet channel 12 for a first heat exchange fluid in the heat exchanger 4. However, in these embodiments the inlet channel 12 is arranged at an upper end of the plate package 8. Accordingly, the inlet conduit 16 is connected to the frame plate 9 at an upper end thereof, and an outlet channel 14 with a matching outlet conduit 18 are arranged at a lower end of the plate package 8 and the frame plate 9.

(18) The pressure pulse damping apparatus 6 further comprises a chamber 24, which communicates with the first conduit 22. In use the chamber 24 is filled with a gas, such as air, and the first heat exchange fluid substantially fills the first conduit 22. The first heat exchange fluid, primary comprising a liquid, forms a liquid surface 60 in the first conduit 22 or the chamber 24. Under stable operating conditions the liquid surface 60 will remain at substantially the same level. When a pressure pulse in the first heat exchange fluid enters the inlet channel 12, the pressure pulse is transferred through the first conduit 22 to the gas filled chamber 24. The gas inside the chamber 24 forms an elastic element. Since the gas is compressible the gas will be compressed by the pressure pulse and thus damp the pressure pulse as explained above. As the pressure pulse compresses the gas in the chamber 24 the liquid level 60 is temporarily raised.

(19) FIG. 6 illustrates a portion of a pressure pulse damping apparatus 6 according to example embodiments. A first conduit 22 leads to a non-shown elastic element. A first opening 62 is adapted to be connected to a through connection of a heat exchanger such that the first conduit 22 is in fluid connection with a first fluid path of a heat exchanger. The elastic element is in fluid communication with the first fluid path only via the first opening 62. A flange 28 is arranged circumferentially around the first conduit 22 at the first opening 62. The flange 28 is provided with through holes 64.

(20) Purely as an example it may be mentioned that a pressure pulse damping apparatus according to embodiments for damping pressure pulses in a heat exchanger used in offshore wet crude oil heating may have the following dimensions. The first conduit of the pressure pulse damping apparatus leads to a cylinder filled with gas thus, forming the gas filled chamber 24. The cylinder has a diameter of 1 meter and an approximate height of 4.6 meters thus, housing a volume of approximately 3600 liters of gas. Inlet and outlet conduits for the wet crude oil of the heat exchanger have typically a diameter in the range of 250-500 mm. A pressure pulse damping apparatus of such dimensions is deemed to cope with pressure pulses commonly occurring in typical offshore wet crude oil handling.

(21) A further example relates to steam condensate cooling. For instance, where in a conduit condensate at a temperature close to the boiling point of the condensate is subjected to a slightly varying pressure, so-called flash vapour may form. As the vapour expands. it will form a vapour pocket that accelerates and pushes a column of condensate at a high velocity through the conduit. As the condensate column has high kinetic energy, it may cause a pressure pulse when it is brought to a sudden stop at an end of the conduit, e.g. in a plate heat exchanger connected to the conduit and forming a condensate cooler. Such a pressure pulse may damage the plate heat exchanger. Again, a pressure pulse damping apparatus may be utilized for damping such a pressure pulse. The following dimensions are presented purely as an example: A condensate conduit leading to a plate heat exchanger for cooling condensate at a flow of about 66.000 kg/h may have a diameter of approximately 150-200 mm. The plate heat exchanger may have an internal volume of approximately 100 liters A gas volume of a gas filled chamber 24 of a pressure pulse damping apparatus 6 may be about 100 liters, e.g. in the form of a cylinder having a diameter of 300 mm and an approximate length of 1.5 m.

(22) Example embodiments described above may be combined as understood by a person skilled in the art. It is also understood by those skilled in the art that heat exchangers benefiting from a pressure pulse damping apparatus may be of many kinds, for example plate heat exchangers provided with gaskets, welded plate heat exchangers, semi-welded plate heat exchangers, and fusion bonded plate heat exchangers.

(23) Although the invention has been described with reference to example embodiments, many different alterations, modifications and the like will become apparent for those skilled in the art. The elastic element may comprise other pressure pulse damping elements than the exemplified gas filled chamber and spring, e.g. may the elastic element comprise an elastomer. The pressure pulse damping apparatus may have other shapes than disclosed. The pressure pulse damping apparatus may be directed in a different direction than disclosed, e.g. horizontally.

(24) Therefore, it is to be understood that the foregoing is illustrative of various example embodiments and the invention is not to be limited to the specific embodiments disclosed and that modifications to the disclosed embodiments, combinations of features of disclosed embodiments as well as other embodiments are intended to be included within the scope of the appended claims.

(25) As used herein, the term “comprising” or “comprises” is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.

(26) As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

(27) As used herein, the common abbreviation “e.g.”, which derives from the Latin phrase “exempli gratia,” may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation “i.e.”, which derives from the Latin phrase “id est,” may be used to specify a particular item from a more general recitation.

(28) The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

(29) Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

(30) It will be understood that when an element is referred to as being “on”, “coupled” or “connected” to another element, it can be directly on, coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on”, “directly coupled” or “directly connected” to another element, there are no intervening elements present.

(31) It will be understood that although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used top distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

(32) Spatially relative terms, such as “beneath”, “below”, “bottom”, “lower”, “above”, “top”, “upper” and the like, may be used herein for ease of description to describe one element's or feature's relationship to other element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Also, as used herein, “lateral” refers to a direction that is substantially orthogonal to a vertical direction.

(33) Example embodiments of the present invention have been described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shape that result, for example, from manufacturing.