Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/08—Elements constructed for building-up into stacks, e.g. capable of being taken apart for cleaning
  • F28F3/083—Elements constructed for building-up into stacks, e.g. capable of being taken apart for cleaning capable of being taken apart
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/08—Elements constructed for building-up into stacks, e.g. capable of being taken apart for cleaning
  • F28F3/10—Arrangements for sealing the margins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
  • F28D2021/0098—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for viscous or semi-liquid materials, e.g. for processing sludge
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D9/0031—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by paired plates touching each other
  • F28D9/0043—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by paired plates touching each other the plates having openings therein for circulation of at least one heat-exchange medium from one conduit to another
  • F28D9/005—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by paired plates touching each other the plates having openings therein for circulation of at least one heat-exchange medium from one conduit to another the plates having openings therein for both heat-exchange media
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F2225/00—Reinforcing means
  • F28F2225/04—Reinforcing means for conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
  • F28F3/04—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element
  • F28F3/042—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of local deformations of the element
  • F28F3/046—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of local deformations of the element the deformations being linear, e.g. corrugations

Definitions

• the present invention relates to a gasket assembly of a plate heat exchanger, comprising at least one gasket and a package of heat exchanger plates which are provided with inlet and outlet ports which constitute channels through the package and between the heat exchanger plates, whereby the heat exchanger plates are permanently joined in pairs to constitute cassettes, the gasket is disposed between the cassettes in a groove in the heat exchanger plates and delimits in combination with the cassettes, in every second space between plates, a first flow passage for a first fluid, and the cassettes delimit a second flow passage for a second fluid.
• the invention also relates to a plate heat exchanger comprising the gasket assembly, a heat exchanger plate and a gasket according to the invention.
• Food manufacture is typically characterised by the need to process and treat highly viscous products, e.g. concentrates for carbonated beverages, juices, soups, dairy products and other products of fluid consistency. For natural reasons, the hygiene aspirations and expectations in this context are extremely high to enable the requirements of various authorities to be met.
• Plate heat exchangers are used in the food industry for a number of different purposes. Problems with regard to so-called dead zones, the accumulation of fibres and other solid material which may be contained in products, and the possibility of flexible and effective cleaning, are extremely important factors in this context.
• the design of heat exchangers therefore plays a crucial part in making it possible for effective heat transfer and hygiene to be achieved while at the same time preventing so-called dead zones in which products may be caught and hence become fertile ground for bacteria growth.
• semiwelded plate heat exchangers i.e. heat exchangers comprising a number of cassettes formed by welding heat exchanger plates together in pairs.
• the weld seam normally runs along the side edges of the cassettes and around the portholes.
• a gasket is disposed between the respective cassettes and is normally made of a rubber material and situated in a groove of the heat exchanger plate.
• One fluid flows inside the cassettes, and another fluid between the cassettes.
• Semiwelded plate heat exchangers tolerate relatively high pressures and make it possible to open the plate package and clean the spaces between pairs of welded heat exchanger plates.
• the welds which replace the gaskets in every second space between plates round the heat exchange surface of the heat exchanger plates reduce the need for gasket replacement and enhance safety.
• the material and configuration of the heat exchanger plates, the design of the heat transfer surfaces with regard to pattern and press depth, etc., are important factors in hygienic applications.
• a critical region of heat exchangers and particularly of heat exchanger plates with regard to dead zones is at the portholes, which are normally provided with a number of so-called nibs, i.e. alternating ridges and valleys, evenly distributed about the porthole in the form of a wave pattern.
• nibs constitute contact points and have the important function of absorbing forces and supporting the structure against the high pressures which occur in the heat exchanger.
• the nibs result in the formation of spaces in the actual flow passage, i.e. dead zones in which flowing liquid may become stationary and solid material contained in the liquid may be trapped and accumulate.
• the gaskets currently used with heat exchanger plates of this type joined together to constitute cassettes take the form of, for example, so-called "clip-on” gaskets, i.e. gaskets locked firmly at the periphery of the heat exchanger plates and around the portholes by protruding locking means disposed in the gasket which are clamped firmly around the edge of the heat exchanger plate. These protruding locking means may also make it more likely that fibres etc. are caught, especially at the portholes.
• GB 809 886 describes a plate heat exchanger for two heat-exchanging fluids whereby the portholes are made circular and plain in order to avoid the problem of fibres and particles being caught. That solution is achieved by the edge of the porthole being pressed outwards to form a flange or collar. The flanges of opposite portholes are so disposed as to abut against one another, thereby forming a smooth channel through the plate package. That solution does however involve manufacturing difficulties.
• the object of the invention is to eliminate or at least reduce the problems indicated above and to provide an improved solution for a porthole of a heat exchanger plate.
• What is in particular aimed at is a new and better gasket assembly specially intended for the portholes of a cassette comprising two heat exchanger plates.
• gasket assembly indicated in the introduction which is characterised in that said gasket in the area around the ports comprises, along its side facing the porthole, a circumferential protruding bead.
• the configuration of the gasket assembly results in great reduction of the so-called dead zones at the portholes. It provides instead a plain surface in the passage through the port channel and substantially avoids the risk of highly viscous liquids which may possibly contain particles or fibrelike products being caught. Should material nevertheless be caught, the plain surface of the gasket in combination with the configuration of the porthole helps to create conditions in which the material will be swept away.
• the gasket assembly according to the invention thus also reduces the risk of bacteria growth, which is a major and important advantage, particularly in areas of application in which the hygiene requirements are extra high.
• the gasket assembly is so configured that the gasket in the area around the ports comprises, along its side turned towards the porthole, opposite recesses on the upper and lower sides of the gasket.
• the heat exchanger plate has about the port a circumferential ridge disposed on the outside of the cassette between the porthole and the gasket groove.
• the ridge and the gasket cooperate in that the bead of the gasket abuts against the circumferential ridge about the porthole, thereby ensuring that the gasket is not dislodged from its position by the high pressures which occur during operation.
• the bead is so configured that the cassettes in combination with the gasket at the ports provide a substantially smooth channel through the plate package.
• the plain surface of the gasket in cooperation with the configuration of the porthole helps to reduce the risk of material being caught.
• the heat exchanger plates are permanently joined together in pairs by welding or brazing.
• the object of the invention is also achieved by a plate heat exchanger comprising at least one gasket assembly according to any one of claims 1-7.
• Fig. 1 depicts schematically a plan view of a gasket assembly comprising a gasket and a heat exchanger plate according to the invention
• Fig. 2 depicts schematically a plan view on a larger scale of the gasket assembly according to the invention
• Fig. 3 depicts schematically a cross-sectional view of various gaskets, whereby the gasket according to A represents a known gasket and the gaskets according to B and C are two alternative embodiments of the gasket according to the invention which are disposed at the porthole of a plate heat exchanger according to the invention, and
• Fig. 4 depicts a perspective view of the porthole of a gasket assembly according to the invention.
• Figs. 1 and 2 depict a cassette 1 comprising two heat exchanger plates 2 permanently joined together and a gasket 3 according to the invention.
• the plates have at least four ports constituting inlet and outlet ports 4, 5, 6, 7 and a heat transfer surface 8 with ridges 9 and valleys 10.
• the cassette 1 may be made by welding or brazing, whereby the two plates 2 are joined together permanently along their periphery and around at least two of ports 4, 5.
• the plates are also so designed that contact points for necessary mechanical support occur largely only on the inside, between two plates which are to be joined together to form a cassette, by opposite ridges abutting against one another.
• the plates abut completely against one another and are joined together permanently so as to form a seal against the fluid which is intended to flow through the portholes.
• Portholes 6 and 7, which constitute the inlet and outlet to the cassettes, are provided instead with nibs 11 which are necessary for providing necessary mechanical support at the porthole.
• the gasket 3 which is preferably made of an elastic material, e.g. rubber material, is disposed in a groove 12 which extends along the periphery of the constituent plates of the cassette and around ports 4 and 5. There is a ring gasket 13 round ports 6 and 7.
• the purpose of the gasket 3 is to seal the space between two cassettes, and it has in the area around ports 4 and 5, along its side facing the porthole, a circumferential protruding bead 14 which may have a cross-sectional configuration such as represented, for example, by the gaskets according to B and C in Fig. 3.
• the gasket may possibly comprise a metal or be surrounded by a second material, e.g. metal, PTFE, etc.
• a circumferential ridge 15 is formed in the plate about the port on the outside of the cassette between porthole 4 or 5 and the gasket groove 12.
• the height of the ridge 15 is such that there is a gap between two opposite ridges when two cassettes are disposed adjacent to one another.
• the gasket 3 is thus situated in the groove 12 in such a way that the bead 14 abuts against the ridge 15 of the constituent plates of the cassettes at portholes 4 and 5.
• FIG. 3 shows how the volume of the dead zone is affected by the cross- sectional configuration of the gasket.
• the gasket 3 has a configuration according to A, i.e. is provided with no bead 14, there is a large space bounded by the gasket A and the heat exchanger plate at the porthole, which is normally surrounded by nibs. This so-called dead zone traps fluid, whereby fibres and other solid materials are caught and thus constitute fertile ground for growth of bacteria.
• the cross-sectional configuration of the gasket is in accordance with the invention according to B, i.e. so that the gasket in the area around the ports comprises along its side facing the porthole a circumferential protruding bead 14, the volume of the dead zone will be greatly reduced.
• the bead 14 abuts against the ridge 15 also results in a smoother surface in the port channel.
• the gasket has a cross-sectional configuration according to C, whereby the bead 14 is so configured that the gasket 3 in the area around the ports comprises, along its side facing the porthole, opposite recesses 16 on the upper and lower sides of the gasket. In this case the whole space at the portholes between two cassettes is largely filled by the gasket, the dead zone is eliminated and a plain smooth surface is formed in the port channel.
• a gasket assembly configured according to the invention whereby a ridge around the porthole in a heat exchanger plate cooperates with a bead of the gasket results in a port channel with maximum possible smoothness of surface, with greatly reduced or no dead zones. This is of great significance, particularly in plate heat exchanger applications where there are strict hygiene requirements, but also in other applications where obstruction and so-called fouling are normally a problem.
• the gasket assembly and the heat exchanger comprising the gasket assembly according to the invention make it possible to achieve a plate heat exchanger which meets high hygiene requirements and is easy to clean.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Steam Or Hot-Water Central Heating Systems (AREA)

Applications Claiming Priority (2)

Publications (3)

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Family Applications (1)

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Citations (2)

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• 2005
  • 2005-01-28 SE SE0500216A patent/SE528847C2/sv unknown
• 2006
  • 2006-01-13 WO PCT/SE2006/000049 patent/WO2006080874A1/en active Application Filing
  • 2006-01-13 DK DK06700449.9T patent/DK1842022T3/da active
  • 2006-01-13 JP JP2007553063A patent/JP5225692B2/ja active Active
  • 2006-01-13 US US11/813,541 patent/US20080196873A1/en not_active Abandoned
  • 2006-01-13 CN CN200680003446.3A patent/CN101124450B/zh active Active
  • 2006-01-13 EP EP06700449A patent/EP1842022B1/de active Active
  • 2006-01-13 ES ES06700449T patent/ES2377509T3/es active Active
  • 2006-01-13 PT PT06700449T patent/PT1842022E/pt unknown
  • 2006-01-13 AT AT06700449T patent/ATE538354T1/de active
  • 2006-01-13 NZ NZ556193A patent/NZ556193A/en unknown
  • 2006-01-13 AU AU2006209162A patent/AU2006209162B2/en active Active

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