WO1982000343A1

WO1982000343A1 - Heat exchanger for flowing media

Info

Publication number: WO1982000343A1
Application number: PCT/NO1981/000030
Authority: WO
Inventors: R Holen; B Borg
Original assignee: R Holen; B Borg
Priority date: 1980-07-11
Filing date: 1981-07-08
Publication date: 1982-02-04
Also published as: NO802084L; NO146579C; NO146579B; EP0055737A1

Abstract

A heat exchanger for flowing media with passages for two media to be heated/cooled arranged within a casing (1) and separated by heat transmission surfaces. Within a closed, oblong casing of preferably circular cross-section there is, in coaxial arrangement, an inner tube (15) the diameter of which is considerably smaller than that of the casing. The tube has an inlet (27) leading from outside and located at one (the first) end of the casing and an outlet at the other, opposite end of the casing, directly connected with the inside of the casing. An outer tube (11) the diameter of which is considerably larger than that of the inner tube and considerably smaller than that of the casing is also provided within the casing. The intermediate space (23) between the two tubes (11, 15) is at one of the two ends provided with an inlet (28) and an outlet (29), separately arranged, and is closed at the other end. The intermediate space (32) between the outer tube and the casing is closed at one end and two helical baffles are arranged in sequence within the intermediate space between the tubes so as to constitute two helical passages (20, 21) connected respectively with the said inlet and outlet. The baffles extend from the end wall of intermediate space (23) comprising the said inlet and outlet, respectively whereas the opposite ends of the baffles terminate at a distance from the opposite end of the intermediate space so that the two helical passages pass into one another at the latter end (22). The casing is provided with a drainage outlet (8).

Description

Heat exchanger for flowing media

The present invention relates to a heat exchanger for flowing media.

Heat exchangers of various types have already been known. As a rule, heat exchangers comprise one or several tube banks the ends of which are connected by rolling or welding to the end plates of the tubular exchanger. To manufacture such heat exchangers is relatively costly and, in addition, they are difficult to maintain and repair. Also hot plate exchangers of various types have been known. Most of them have the common feature that they require many seals and are prone to leakages.

The object of the invention consists in bringing about a heat exchanger consisting of few sturdy parts which can be easily assembled and easily dismantled, the individual parts being easily replaced if necessary. Another object of the invention consists in bringing about a heat exchanger the width and length of which is small by comparison with the size of the heat exchanging surface and the efficiency attained. These characteristics are achieved by bringing about a heat exchanger with the characteristics stated in the claims. In a heat exchanger in accordance with the invention the medium to be heated is passed to and fro along a double helix in the space between the heating surface tubes, subject to one 180° reversal while passing through the heat exchanger, as a result of which the pressure drops to a relatively slight degree and the energy required for pumping is correspondingly reduced. Another advantage with the design according to the invention consists in the fact that the construction requires relatively little precision, which is conducive to more economical production.

The invention is explained in greater detail below with the aid of an example and with reference to the drawing which shows a longitudinal section through a heat exchanger in accordance with the invention. The heat exchanger can be used for heating/cooling of different media, but in the example it is assumed that it serves for heating water with the aid of steam. The drawing shows a horizontal design of the heat exchanger but a vertical design is equally feasible.

The heat exchanger comprises a cylindrical casing 1 with a wall 2 and a base 3. One end, 4, of the casing is open and ends in an outer flange ring 5. The casing 1 is preferably installed in an insulating enclosure 6 containing insulating material 7. The wall 2 of the casing is provided with an outlet socket 8, in the present case for steam condensate. The casing is also provided with a support or brackets 9. Coaxially within the casing 1 there is a tubular insert 10 comprising two tubes one inside the other, the outer tube of which is designated 11 and has at one end an outer flange ring 12 which is the same size as the casing flange ring 5. its other end being provided with an inner flange ring 13 with an opening 14. The diameter of the outer tube 11 is considerably smaller than that of the casing 1. There is also a considerable distance between flange 15 of the tube and base 3 of the casing.

Coaxially with the outer tubs 11 there is within it an almost equally ϊong inner tube 15 the diameter of which is considerably smaller than that of the outer tube. At one of its ends the inner tube 15 is provided with a blind flange 16 having the same outer diameter as flange ring 5 of casing 1. A t its other end the inner tube 15 has an outer flange ring 17 the outer diameter of which is

end of the tube is open and aligned with the flange opening 14 in the outer tube. The lengths of tubes 11 and 15 are such that the flange rings 13.17 abut one another when the tube flanges 12,16 are in contact. Two helical baffles or vanes 18 and 19, respectively, are attached to the inner tube 15, forming between themselves two continuous helical passages 20 and 21, respectively. The baffles 18, 19 are finnly attached to the inner tube 15 and have an outer diameter matching the inner diameter of the outer tube 11. At one end of the inner tube the ends of baffles 18,19 are attached at two roughly diametrically opposite points to the end flange 16, whereas the other ends of the baffles terminate at some distance from the flange ring 17, so that the passages 20,21 connect in the end part 22 of the intermediate space. The intermediate space itself is designated 23. When the heat exchanger is in its assembled state the flange rings of the tubes, 13 and 17. are screwed together with the aid of bolts 24 and nuts 25, thus tightly closing the end part 22 of intermediate space 23.

The end flange 16 of the inner tube 15 is provided with a central inlet socket 27 in the present case for the introduction of heating steam. In addition, the end flange 16 is provided with two dia metrically opposite sockets, i.e. the inlet socket 28 for water that is to be heated and the outlet socket 29 for water that has been heated. The inlet socket 28 is directly connected with the passage

20, and the outlet socket 29 is directly connected with the passage

21. At the end of the heat exchanger presently under discussion the flanges 5, 12 and \ G are provided with aligned holes for screwing together with the aid of bolts 30 and nuts 31. The outer intermediate space is designated 32.

When the heat exchanger is in operation, the medium to be heated, in the present case water, is fed through socket 28 and will flow along one of the helical passages, 20, towards the end part 22 or intermediate space 23, where it is subjected to a change of direction amounting to 180° and will continue to flow back through the passage 21 leaving the heat exchanger in a heated condition through the outletsocket 29. Superheated steam is fed through the central socket 27 and passes through the inner tube 15 and then, at base 3, through the intermediate space between the outer tube and the casing and along wall 2, whereupon it leaves the casing as cooled steam or condensate through the outlet socket 8. Heat from the steam is transmitted to the water both through the inner tube 15 and the outer tube 11. A certain transmission of heat also takes place through the baffles 18, 19. Various flowing media can be heated or cooled, respectively. Such media are oil, brine, paint, air and various gases etc.

To dismantle the heat exchanger one first releases the bolt 30 and withdraws the tubular insert 10. Then the bolt assembly 24,25 is dismantled and the inner tube drawn out of the outer tube. The capacity of the heat exchanger can be adapted in accordance with the various applications by altering the total length of the heat exchanger, altering the pitch of the helical baffles and altering the radial height of the baffles. Welded steel construction is preferable but other materials and methods of fabrication are feasible.

Modifications are possible. Casing base 3 may, for instance, be replaced by a cover. The "helix" may in this case be turned by 180° within the intermediate space 23 and the sockets 28,29 may pass through the cover. However, the design described is simplest. With a vertical design the outlet 8 would be provided in base 3.

Claims

C l a i m s

1. A heat exchanger for flowing media comprising an outer casing (1) with passages for the two media to be heated/cooled within the casing and separated by heat transmission surfaces, c h ara c t e r i s e d in that, within a closed, oblong casing (1), preferably of circular cross-section, there are, in coaxial arrangement, an inner tube (15), the diameter of which is considerably smaller than that of the casing, with an inlet (27) from outside one (the first) end of the casing and with an outlet at the other, opposite end of the casing directly connected with the inside of the casing, an outer tube (11 ), the diameter of which is considerably larger than that of the inner tube and considerably smaller than that of the casing, whereby the intermediate space (23) between the two tubes (11,15) has at one end, separately arranged, an inlet (28) and an cutlet (23) and is closed at its other end, and the intermediate space (32) between the outer tube and the casing is closed at one end, in that two helical baffles are arranged in sequence within the intermediate space between the tubes and constitute helical passages (20,21) which are, respectively, connected with the said inlet (28) and the outlet (29), the said baffles extending from the end wall of intermediate space (23) comprising the said inlet (28) and outlet

(29), respectively, whereas the opposite ends of the baffles terminateat a distance from the opposite end of the intermediate space so that the two helical passages pass into one another at the latter end (22), and in that the casing (1) is provided with at least one drainage outlet (8).

2. A heat exchanger in accordance with claim 1, c h a r a c t e r i s e d in that the first, open end of casing (1) is closed by an outer flange ring (5) and the other end ist closed by a base (3) and in that the first end of the inner tube is closed by a flange (lo) with an inlet (27) leading to the inner tube (15) and with an inlet (28) and an outlet (29) leading to/from the intermediate space (23), the said flange having a diameter which roughly corresponds to that of the casing flange ring (5) and in that the other end of the inner tube is provided with a flange ring which closes or is equipped to close the intermediate space (23).

3. A heat exchanger in accordance with claim 1 or 2, c har a o t e r i s e d in that the outer tube (11) has at its first end a flange ring (12) with roughly the same diameter as that of the casing and at its other end an inner flange ring (13) which closes or is equipped to close the intermediate space (23).

4. A heat exchanger in accordance with one of claims 1 to 3, c h ar a c t e r i s e d in that the baffles (18,19) are firmly connected with the inner tube and at the ends with flange (16) of the inner tube (15), which is designed as a blind flange.