TUBE HEAT EXCHANGER

Abstract: A tube heat exchanger comprises tubes (38) or bundles of relatively narrow long tubes (38) surrounded by jacket tubes (1-4; 41). One of the media streams inside the narrow tubes and the other medium in the jacket tubes. The tube heat exchanger is particularly characterized in that one (40) of the gables of the tube (38) or the bundle of tubes (38) is provided with a circular-cylindrical sealing sleeve (44) which is slidably mounted in the jacket tube (41).

Description: Tube heat exchanger This invention relates to a tube heat exchanger for transfer of heat between two media, comprising a number of relatively narrow and long, essentially straight tubes arranged separately or in bundles, the tubes in each of their ends being fastened onto gables and arranged to conduct one of the media inside them¬ selves, and each tube or each bundle of tubes being surrounded by a jacket tube arranged to conduct the other medium inside itself, which jacket tubes are essentially parallel and are kept together in a medium-conducting and supporting way by tube connections mounted between the ends of the jacket tubes and projecting from the walls of the jacket tubes. Such tube heat exchangers are known since long and are usually called "slender-type tube heat exchangers" . The relatively narrow tubes have an inner diameter in the size of a couple of mm to a couple of cm. The jacket tubes are usually communicating with each other by means of U-formed tube bends, which are either welded to the ends of the jacket tubes or applied thereto by means of flanges or bolts. In both cases some form of frames is required to carry up the jacket tubes in that case when the plane of the jacket tubes is horizontal as well as vertical, which later case is the most common one. In many applications it is necessary to adapt in an easy way the heat area of the tube heat exchanger of the kind mentioned by way of introduction to the existing need. This is not done in an easy way with heat exchangers of this type existing until now. It is also desirable that the narow tubes in an easy way shall be able to be taken out of the heat exchanger for inspec¬ tion ;_nd cleaning. The object of this invention Is to bring about a tube heat exchanger of the kind mentioned by way of introduction which does not have the drawbacks and limitations that are connected with such heat exchangers known until now. Furthermore, an essential object with the Invention is to bring about a tube heat exchanger which has an inherent compensation for the thermal tensions which can arise in the tubes being Inside the jacket tubes. According to the invention such a tube heat exchanger is parti¬ cularly characterized in that one of the gables of the tube or of the bundle of tubes Is provided with a circular-cylindrical sealing sleeve slidably mounted in the jacket tube. With this design the tubes or the bundles of tubes can rela¬ tively freely expand or contract, whereby the risk that thermal tensions shall be built up In the tubes is eliminated. In a suitable embodiment of the invention the sealing sleeve is slidably sealing towards two gaskets axially separated from each other in a flange connected with the jacket tube, a drain channel with outlet being arranged between the gaskets. By this arrangement a simple and secure leakage indication is received before the leaking medium has penetrated the two gaskets. According to another embodiment the other gable of the tubes or the bundles of tubes is detachably sealed towards the jacket tube such that the tubes or the bundles of tubes are easily reachable for extraction out of the jacket tubes since a tube bend connecting the tubes or the bundles of tubes has been removed. According to a further embodiment the sealing sleeve at its inner part is provided with a sliding sleeve with a larger diameter than the diameter of the sealing sleeve, whereby the surface of the sealing sleeve is protected when extracting and inserting the tubes or the bundles of tubes out of and into the jacket tubes. The invention shall now be described more closely with reference to the accompanying drawings, in which Fig. 1 shows a view of a tube heat exchanger according to the invention with a group of jacket tubes; Fig. 2 shows a view of a tube heat exchanger according to the invention with two groups of jacket tubes; Fig. 3 shows a longitudinal section through a jacket tube with a bundle of narrow tubes and their gables and (partly) con- nections belonging to them; Fig. 4a and b show two cross-sections through a bundle of narrow tubes according to the invention. In Fig. 1 there is shown a group, or module, comprising four jacket tubes 1, 2, 3 and 4, which are arranged parallel with the symmetry axes in one plane. As appears from the figure the entire length of the jacket tubes is not shown. The jacket tubes 1 and 2 are at their ends joined by tube connections 5> 6. In a corresponding way tube connections 7 and 8 join the jacket tubes 2 and 3, and tube connections 9 and 10 the jacket tubes 3 and 4. The tube connections 5, 7 and 9 have a common symmetry axis, i.e. they are in alignment, which is also the case for the tube connections 6, 8 and 10. In line with the tube connections 5, 7 and 9 is a pipe socket 11 mounted on the jacket tube 1 and a pipe socket 12 on the jacket tube 4. In a corresponding way the jacket tubes 1 and 4 are in their other ends provided with pipe sockets 13 and 14. The bundles of narrow tubes Inside the jacket tubes 1 to 4 are not shown in this figure. However, a connection 15 comprises an intake for the medium streaming inside the narrow tubes. 16, 17 and 18 are tube bends which are parts of the flow way for this medium and 19 is a connection for taking out this medium. In the tube connection 6, 7 and 10 and in the pipe socket 12 there are mounted blocking means 20, 21, 22 and 23 in the form of blocking plates. Moreover, the pipe sockets 11 and 12 are closed with covers 24 and 25. Due to that a flowway for the second medium Is received with an intake through the pipe socket 14, further through the jacket tube 4, in opposite direction through the jacket tube 3, in a direction opposite to the last-mentioned one through the jacket tube 2 and then at last In opposite direction and out through the pipe socket 13. In Fig. 2 Is shown how two groups 26 and 27 with eight jacket tubes in each are connected to each other by means of connec¬ tions between pipe sockets 28, 29 and 30, 31. A lower pipe socket 32 is mounted on a supporting foot 33 while another lower pipe socket 34 is connected to an intake piece 35 for the second medium. The Intake piece 35 is fixed to a subjacent bottom plate, while the supporting foot 33 is mounted slidably in a supporting way towards the same by means of an intermediate layer, for instance of polytetrafluoroethylene, in order to admit thermal movement of the heat exchanger. The two groups of jacket tubes with contents are essentially kept up by the tube connections between the jacket tubes and the pipe sockets. In order to prevent a movement in the horizontal direction a couple of supporting units 36 and 37 are mounted at the uppermost jacket tube. In Fig. 3 there is partially shown a bundle of narrow tubes 38 with gables 39 and 40. The gable 39 seals immovably, but detach- ably, towards a flange 42 by means of a gasket 43 which flange is welded onto the jacket tube 41. The gable 40 is connected with a sealing sleeve 44 slidably mounted in a flange 46 pre- ferably fastened onto the jacket tube 41 by means of welding. Due to that heat expansion and contraction of the tubes 38 with the gables 39 and 40 can be automatically compensated, wherefore the formation of thermal tensions leading to the burst of welds and the break of the tubes is prevented. The sealing sleeve 44 slidably seals towards two gaskets 45a, b in the flange 46, which are axially displaced a part in relation to each other. A drain channel with outlet 47 is arranged between the gaskets 45a and 45b. If anyone of the gaskets should let one or the other of the media to pass, this is shown by an indicating outflow. The connection pieces 48 and 49 are screwed onto the flanges 42 and 47, Intended to lead one of the media like streams Inside the narrow tubes 38. In Fig. 3 are also (partially) shown tube connections 50, 51, 52 and 53. In the tube connections 50 is shown a blocking means 54 in the form of a plate. In Fig. 4a there is shown a cross-section along the line IVa-IVa in Fig. 3. As is apparent from the figure, In this case the bundle comprises eight tubes 38 which are surrounded by the jacket tube 41. Fig. 4b shows a cross-section through a bundle, through a keeping and distance means 55 which is mounted around and into the bundle in order to keep the tubes 38 evenly distri¬ buted in the cross-section. With regard to the risk of damages on the sealing sleeve when the bundle with tubes 38 are extracted from the jacket tube it is suitable to provide the sealing sleeve 44 at its inner part with a sliding-sleeve 56 having a somewhat larger diameter than that of the sealing sleeve. The sliding sleeve is arranged to protect the surface of the sealing sleeve when extracting and inserting the bundle of tubes out of and into the jacket tube. This sliding sleeve will then slide towards the inner wall of the jacket tube. In Fig. 4 eight slender tubes have been shown in each jacket tube. However, it is within the- scope of this invention to vary the number of slender tubes in the jacket tube from one and upwards, depending on the medium that shall be conducted through the slender tubes and the heat exchange capacity that is desired.

Claims: Claims 1. Tube heat exchanger for transfer of heat betwen two media comprising a number of relatively narrow and long, essentially straight tubes (38) arranged separately or In bundles, the tubes (38) in each of their ends being fastened onto gables (39, 40) and arranged to conduct one of the media inside themselves, and each tube (39) or each bundle of tubes (38) being surrounded by a jacket tube (1-4, 41) arranged to conduct the other medium inside itself, which jacket tubes (1-4, 41) are essentially parallel and are kept together in a medium-conducting and sup¬ porting way by tube connections (5-10) mounted between the ends of the jacket tubes (1-4, 41) and projecting from the walls of the jacket tubes (1-4, 41), c h a r a c t e r i z e d i n that one (40) of the gables of the tube (38) or the bundle of tubes (38) is provided with a circular-cylindrical sealing sleeve (44) which is slidably mounted in the jacket tube (41). 2. Tube heat exchanger according to claim 1, the jacket tube comprising a flange (46) fastened onto the jacket tube by means of welding, c h a r a c t e r i z e d i n that the sealing sleeve (44) is slidably sealing towards at least one gasket (45a, b) in the flange (46). 3. Tube heat exchanger according to claim 2, c h a r a c ¬ t e r i z e d i n that the gaskets (45a, b) are two in number and placed with an axial distance to each other, and that a drain channel (47) with outlet is arranged betwen the gaskets (45a, b). 4. Tube heat exchanger according to anyone of the preceding claims, c h a r a c t e r i z e d i n that the tubes (39) or the bundles of tubes (38) are mounted extractable out of their jacket tubes (41), their other gable (39) being mounted detachably and immovably sealed towards the jacket tube (41). 5. Tube heat exchanger according to anyone of the preceding claims, c h a r a c t e r i z e d i n that the sealing sleeve (44) at its inner part is provided with a sliding sleeve (56) having larger diameter than the sealing sleeve (44), mounted for protecting the surface of the sealing sleeve (44) when extracting and inserting the tube (38) or the bundle of tubes (38) out of and into the jacket tube (41).

Inventors: PALM BENGT, PALM, BENGT
Applicants: ALFA LAVAL FOOD & DAIRY ENG, ALFA-LAVAL FOOD & DAIRY ENGINEERING AB
Application year: 1985
Main classification: F28D7
IPC codes: F28D7, F28F9