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EP-4627274-B1 - HEAT EXCHANGER

EP4627274B1EP 4627274 B1EP4627274 B1EP 4627274B1EP-4627274-B1

Inventors

  • OWSTON, Jeremy Henry

Dates

Publication Date
20260506
Application Date
20231114

Claims (8)

  1. A shell and tube heat exchanger (1) having an outer shell (5a, 5b) and a series of heat exchange tubes (8a, 8b) located therein, said shell comprising a shell side fluid inlet (2a) and a shell side fluid outlet (2b) for transfer of a first fluid (6a), said tubes, capable in use of permitting flow of a second fluid (7a) therethrough, said tubes comprising a first end (4a) and second end (4b), wherein said tubes are arranged such that they are touching, forming a hypocycloidal enclosure gap (9a) therebetween, said hypocycloidal enclosure gap provides a path for the transfer of said first fluid, wherein said tubes comprise a first region of reduced diameter located proximate to said shell side fluid inlet and second region of reduced diameter located proximate to said shell side fluid outlet, to allow said first fluid to form a flow path through said hypocycloidial enclosure gap, wherein the first end and/or second end of said tubes comprise a cross section shape which is tessellating.
  2. A heat exchanger according to claim 1, wherein the first end and second end of said tubes are secured at their open ends through a tube sheet.
  3. A heat exchanger according to claim 1 or claim 2, wherein the cross section shape is a hexagon.
  4. A heat exchanger according to any one of the preceding claims, wherein the transition from the tube to said tessellating tube end comprises a back-brazed joint (41).
  5. A heat exchanger according to any one of the preceding claims, wherein said a hypocycloidial enclosure gap is formed from three touching tubes to form a triangular pitch configuration.
  6. A heat exchanger according to any one of claims 1 to 4, wherein said a hypocycloidial enclosure gap is formed from four touching tubes to form a square pitch configuration.
  7. The heat exchanger according to any one of the preceding claims, wherein the tubes are straight and there is at least one end cap located in the end cover space located at each end of the tubes.
  8. The heat exchanger according to any one of claims 1 to 6, wherein the tubes are U-tubes and there is only one end cover wherein both end caps are located within said end cover.

Description

FIELD The present invention relates to shell and tube heat exchangers, specifically to compact heat exchangers without the need for a tube sheet. BACKGROUND Shell and tube heat exchangers are a common form of heat exchanger, which typically comprise an arrangement of tubes supported by tube ends, baffles, lattices and tie rods to provide a controlled flow path through shell body. DE 102012012939 A1 relates to a heat exchanger for cooling a fluid of an internal combustion engine, in particular a charging fluid of a charged internal combustion engine, in particular of a motor vehicle, featuring an outer pipe section, in which are disposed at least one inner pipe section with at least one channel for the fluid to be cooled and in which is disposed at least one cooling fluid channel for a cooling fluid, the at least one cooling fluid channel and the at least one channel for the fluid to be cooled being in heat contact and separated fluid-tightly from each other. US 2016/318138 A1 relates to heat exchange systems, and in particular, to a design for improved manufacturability of a header particularly suitable for a supercritical heat exchanger. US 2017/198979 A1 describes a heat exchanger including a body made of polymer, a plurality of first flow channels defined in the body, and a plurality of second flow channels defined in the body. The second flow channels fluidly isolated from the first flow channels. US 2014/262174 A1 describes a flat tube heat exchanger encompassing a closed housing, in which two tube sheets and a tube bundle, which is arranged between the tube sheets and which is supported by the tube sheets is arranged. SUMMARY According to an aspect of the present invention, there is provided a shell and tube heat exchanger as disclosed in claim 1. The shell and tube heat exchanger has an outer shell and a series of heat exchange tubes located therein, said shell comprising a shell side fluid inlet and a shell side fluid outlet for transfer of a first fluid,said tubes, capable in use of permitting flow of a second fluid therethrough, said tubes comprising a first end and second end, wherein said tubes are arranged such that they are touching, forming a hypocycloidal enclosure gap therebetween, said hypocycloidal enclosure gap provides a path for the transfer of said first fluid,wherein said tubes comprise a first region of reduced diameter located proximate to said shell side fluid inlet and second region of reduced diameter located proximate to said shell side fluid outlet, to allow said first fluid to form a flow path through said hypocycloidial enclosure gap, wherein the first end and/or second end of said tubes comprise a cross section shape which is tessellating. Typically heat exchangers have a tube pitch of at least 1.25, such that there is sufficient volume for the first fluid to flow inbetween the tubes. In order to ensure that the first fluid flows along the entire length of the tubes, baffles and tie rods are used to direct and control the flow of the first fluid such that the first fluid remains in contact with the tubes for the maximum path length. The use of tubes that form a hypocycloidial enclosure gap, with a pitch of substantially 1, provides a path for the transfer of said first fluid, there is no further need for baffles to direct the flow along the tubes. The hypocycloidial enclosure gap may be formed from three or more touching tubes with a pitch of substantially 1. Preferably there are three or four touching tubes, to provide a triangular or square pitch configuration, respectively. Clearly, larger numbers of tubes may be used, which will increase the flow of the first fluid through the hypocycloidial enclosure gap, however the system will be less efficient as there may be fewer tubes per unit volume. Preferably there are three touching tubes to provide triangular pitch configuration with a pitch of substantially 1. The tubes abut along their length. The tubes may be fixedly attached along their length, however preferably there are one or more tube bundle supports, at the extremity of the bundle to provide support between the outer tube bundle and the shell. The tube bundle supports may stop flow fluid passing around the outside of the tube bundle whilst also offering structural support to the tube bundle to prevent it sagging in the middle. Typical prior art heat exchangers may comprise fins, pleats or projections, so as to increase the surface area of the tubes. The use of only substantially smooth tubes, with no projections or relief structures, provides the maximum flow of fluid through the tubes, as the diameter of tube can be maximised. The first and second region of reduced diameter are such that they allow the first fluid to pass from the fluid shell inlet through into the hypocycloidial enclosure gap along the length of the tubes and finally out of the fluid shell outlet. The reduced diameter may occur for a length of up to 20% of the length of the tube, preferably up to