NZ195663A - Coiled tube heat exchanger:shell inlet tangential to turn of coil - Google Patents

Description

FORM 5. 4' Reg -19.U) NEW ZEALAND 195663 Fee: $55.00 t2Novw8iT| ^ A \ PATENTS ACT 195 3 Insert number of Phovi siona L Speci fica"tion( s) (if any) and da"te( s) of fi Ling; otherwise leave bLank.

Number: 195663 Date: 27 November 1980 COMPLETE SPECIFICATION Insert Title of Invention.

Insert fu 11 name, fu 11 street address and nationality of (each) applicant.

HEAT EXCHANGER I/WE MICON ENGINEERING LIMITED, a New Zealand company of 69 Gilletta Road, Mt Roskill, Auckland, New Zealand hereby declare the invention for which I/we pray that a patent may be granted to me/us and the method by which it is to be performed, to be particularly described in and by the following statement:- Indicate if following page is numbered '1 (a)1 1.5.80 This invention relates to a heat exchanger.

In the past, many heat exchangers have been provided in which a tube carrying one fluid passes through a chamber carrying a C ' second fluid, in such a manner .that heat may be transferred through the walls of the tube from one fluid to the other. In general, the tube is mounted in a first direction and the fluid within the chamber travels in a second direction transversely to the first one. The fluid within the chamber 10 travels relatively slowly, which inhibits efficient heat transfer.

The object of the present invention is to provide a means whereby the first and second fluids in a heat exchanger can 15 travel along parallel paths in the same or opposite directions at desired velocities.

Accordingly, the present invention provides a heat exchanger comprising: (a) a coiled tube of a plurality of turns each axially spaced apart from those turns adjacent having an inlet and an outlet for a first fluid to flow through the tube; (b) a conduit forming an inlet for a second fluid, the conduit being disposed to discharge the second fluid to impinge on 25 the tube between turns of the coiled tub'e and 2 • a I substantially tangentially to a turn of the coiled tube; (c) an outlet from the heat exchanger for the second fluid; and (d) a wall which is substantially concentric with the said C coiled tube and spaced slightly apart and outwardly therefrom, the wall being disposed relative to the said conduit to deflect the second fluid aftier discharge of the second fluid from the conduit into a flow path which substantially follows alongside the path of the turns of 1° the coiled tube.

The above gives a broad description of the present invention, preferred forms of which will now be described with reference to the accompanying drawings in which: Figure 1 is a general perspective view illustrating the principle of the present invention; Figure 2 is an end view of the arrangement shown in Figure 1; Figure 3 is a general perspective view of a variation of the arrangement shown in Figure 1; Figure 4 is a longitudinal view of a first embodiment of the present invention; Figure 5 is a cross sectional view of the heat exchanger shown in Figure 4; Figure 6 is a longitudinal section view of a second embodiment 25 of a heat exchanger according to the>p^esent invention; 195663 Figure 7 is a cross sectional view of the heat exchanger shown in Figure 6; Figures 8 and 9 are views similar to Figures 6 and 7 respectively, showing a possible variation on the 5 second emobdiment; Figure 10 is a longitudinal sectional view of a third embodiment of the present invention; Figure 11 is a cross sectional view of the heat exchanger shown in Figure 10; Figure 12 is a longitudinal section showing a fourth embodiment of a heat exchanger according to the present invention; Figure 13 is a cross sectional view of the heat exchanger shown in Figure 12; Figure 14 is a longitudinal sectional view of a fifth embodiment of the present invention; Figure 15 is a longitudinal sectional view of a sixth embodiment of the present invention; Figure 16 is a cross sectional view of a variation within the 20 scope of the present invention; and Figure 17 is a sectional view of a seventh embodiment of the present invention.

Turning now to the arrangement shown in Figures 1 and 2 the 25 heat exchanger of the present invention generally comprises an 195663 outer wall, defining a chamber, typically cylindrical, with a fluid inlet 13 arranged substantially tangentially to the wall of the chamber, and a fluid outlet 15 at the other end of the chamber. Mounted within the chamber is a helical tube 17 5 having an inlet 19 leading to an axial feed portion 21 of the tube and an outlet 23. Within the coils of the tube 17 is a cylindrical wall 25 defining an annular space 27 between the walls 11 and 25.

If a first fluid is passed in through the inlet 19 to the tube 17 it will rotate around the coils of the tube in the direction indicated by the arrows 29 and pass out through the outlet 23. A second fluid passed in through the inlet 13 into the annular chamber 27 will, because of the tangential 15 arrangement of the inlet, be caused to circulate around the chamber in a rotational manner. Because of the helical coil within the chamber, the fluid will be induced to travel in a helical direction, in the direction of the arrows 31, towards the outlet 15. The two fluids will thus travel past each 20 other (separated by the walls of the tube 17) in opposite directions.

Turning now to Figure 3, the arrangement shown here differs from that of Figures 1 and 2 in that the inner wall 25 25 defining the annular space 27 is missing, and a second coiled 195663 tube 33, with inlet 35 leading to an axial feed-in tube 37, and outlet 39, has been placed within the coils of the first tube 17. There is no outlet 15 for the fluid travelling within the chamber 11, but rather the fluid, when it reaches 5 the far end 41 of the chamber travels outwardly as indicated by the arrows 43 as a result of centrifugal action. Such an arrangement is typically used for passing fluid into a storage chamber, heating or cooling it via the tubes 17, 33 as it enters.

Figures 4 and 5 depict a simple heat exchanger along the lines illustrated in Figures 1 and 2. (Corresponding reference numbering, using the same final two digits for corresponding parts, has been used for ease of understanding, as has also 15 been done with the rest of the drawings). However, a baffle 145 in the form of a continuous helix is also shown between the coils of the tube 117. This is an optional addition to assist in directing the helical flow of the fluid within the annular space 127. (In this and some other drawings the 20 baffle is only partially shown, for clarity). The baffle may extend part way or all of the way across the space 127.

As well as the outlet 115 from the annular space 127, two alternative outlets 147 and 149 are illustrated in Figure 4. 25 The outlet 147 merely collects the swirling fluid from the 195663 annular space 127 as it collects at the end 141 of the chamber. Alternatively, the outlet 149 will collect the fluid after it is passed around through the end space 141 and travelled back up inside the inner wall 125. The flow through 5 the central space will be substantially axial. The complete inner assembly 117, 121, 125, 145 may be removed from within the vessel 111 after removing bolts in the end flange 150 of the vessel.

Figures 6 and 7 illustrate a variation of the arrangement shown in Figures 4 and 5. In this arrangement, instead of a single tube 117 there are two tubes 217. Again, an optional baffle 245 may be used. Otherwise, the arrangement is substantiallythe same as that shown in Figures 4 and 5. Any 15 other number of coiled tubes may also be used.

Figures 8 and 9 are identical to Figures 6 and 7 respectively except that the inlets 219 and said tubes 221 are replaced by a single inlet 319 and a single feed tube 321 leading to a 20 plurality of radial feed tubes 322 feeding into the helical tubes 317. Also, an alternative outlet 349 is illustrated.

Assembly and dismantling of the heat exchanger can be achieved by the same methods as outlined above. "" 15 MAR 385 £ /' 195683 Figures 10 and 11 illustrate yet another variation on the theme. In this instance fluid enters the central cylindrical chamber 451 via an inlet 453 and then travels to the inlet 419 of the tube 417. It travels through the tube to the outlet 5 423 and thence into an annular space 455 between the wall 411 of the annular chamber 427 and an outer annular chamber 457. Helical flow within the spaces 451 and 455 (as well as within the chamber 427) may be induced either by the use of tangential inlets 453, 423 or by the use of helical or other 10 baffles, or by a combination.

The fluid within the chamber 455 then leaves via an outlet 459.

This embodiment is not as simple to assemble and disassemble as the others described above.

Versions of this embodiment with a plurality of tubes 417, or a plurality of annular chambers 427, may also be used. There 20 may also be tubes within the chambers 425 and 455 instead of direct inlet and outlet pipes 413, 415.

Figures 12 and 13 illustrate an embodiment which, to some extent, resembles the arrangement described with reference to 25 Figure 3, in that the heat exchanger is open at one end 541 .yv o'-. o 'rf> 195663 (which may, if desired, be flared as shown) enabling the fluid to. pass out under centrifugal action into a main storage vessel defined by a shell 561. Otherwise, however, it more closely resembles the arrangement of Figures 1 and 2, the main difference being that the axial feed tube 21 has been replaced by a helical coil 563 connected to the main helical portion of the tube 517 by means of a U bend 565.

The space 551 within the inner wall 525 may also be provided with an inlet 567 from the vessel arranged to induce helical flow within the chamber opposite to the rotational direction of the fluid flow within the tube 563. This flow would be induced by the rotation of the fluid escaping from the chamber 527 as indicated by the arrows 543.

Because this fluid entering the storage vessel 561 at the end 541 of the heat exchanger is travelling with a rotary movement, this rotation is likely, to some extent, to be imparted to the main fluid within the storage vessel. This encourages circulation of the fluid within the storage vessel and inhibits stratification of the stored fluid. This effect may be enhanced by the flaring of the end 541 of the heat exchanger as shown. / 195663 This form of heat exchanger may be modified by omitting the inlet 567 and replacing the helical coil 563 with a plain connecting pipe from the inlet 519 to the coil 517.

Disassembly is similar to that described for the embodiment of Figures 4 and 5 above.

Figure 14 shows a form without an inner cylindrical wall 25. The tangential inlet 813 is depended upon for imparting a helical flow to the fluid which will substantially follow the path of the coil 817 around the wall of the chamber 811.

Figure 15 shows a unit which is similar to the arrangement shown in Figure 14, except that a baffle 945 has been added.

Figure 16 illustrates that the tube 17 (Figure 1) need not necessarily be strictly helical, but that the coil may be any of many different shapes. The tube 1017 illustrated is a series of short straight sections 1087 interconnected by sharp bends 1089. The bends may be in the cross sectional and/or the longitudinal plane of the heat exchanger.

Alternatively the coils can be crimped or otherwise deformed to induce turbulence in the fluid flow, which may be an advantage in situations where the fluid might otherwise tend \N 2 15NAR:w5 r 195663 to be laminar if no turbulance is induced, or where the heat exchange rate could usefully be enhanced by the use of turbulance.

Instead of helical tubes, spiral tubes may be used, the counterflow in the main chamber being arranged to spiral around the tubes along a path parallel to the tubes.

Figure 17 shows a preferred spiral arrangement, in which the spiral has been arranged in a multi-layered, conical form. The heat exchanger 1111 has a tangential primary inlet 1113 and a central primary outlet 1115. Within the space are four spiral coils 1117, each provided with an inlet 1119 and an outlet 1123. Only two of the inlets and outlets are shown, the other two being arranged in a similar manner on a plane perpendicular to the plane shown in the drawings, so that the four inlets and outlets are spaced 90 degrees from each other. Thus the secondary fluid is caused to flow in a spiral direction through each of the tubes 1117 while the primary fluid flows in a spiral direction, following the paths of the tubes 1117, in the opposite direction. Spiral baffles 1145 help to ensure that the primary fluid flow follows the required spiral direction. 195663 The conical shape shown in Figure 17 may have the advantage that it avoids airlocking problems which could occur if the spirals were flat, and it may also give gravity collection advantages for some fluids when the exchanger is mounted with structural strength to the unit than would be the case with a flat spiral unit. However, a flat spiral unit may still be usefully used in some applications.

Various other modifications to the spiral form of the present invention are also possible, including a single spiral tube 1117, or any other number of tubes, and many other of the variations described with reference to the Figures 4 and 16 inclusive. ' Many other modifications may be made to the above without departing from the scope of the present invention as broadly defined. For example, many of the features which have been shown in one or more of the embodiments may also be 20 incorporated in other embodiments where they are not shown. Some embodiments of the present invention may be used vertically as well as horizontally.

The present invention may be used with chambers and tubes of 25 other shapes also, the main requirement 1 flow its axis vertical. The conical housing also gives greater 195683 within the main chamber is induced to be in a direction closely following that of the flow within the tube or tubes and at controlled, selected or imposed velocities, whether in the same or opposite directions.

In each of the embodiments described above, the fluid flow within the tube and within the space around the tubes have been described as being in opposite directions. However, for each embodiment, one or both flow directions may be reversed, 10 with some modifications where required, to ensure that the inlets are tangential where this is required for example. In some applications it may be advantageous to have both fluids flowing in the same direction, but it is still important to the working of the present invention that the flows be 15 substantially parallel.

The heat exchangers and the tubes may be of any desired lengths, widths, diameters, etc, and made of any suitable materials.

Thus, the present invention provides a heat exchanger in which the primary and secondary fluids travel along parallel paths in the same or opposite directions. The velocities can be relatively high. The exchanger is simple in its construction, and in many of its forms, readily enables easy dismantling for y 195663 inspection, cleaning and repair. The heat exchanger works quite effectively with plane surfaced tubing although ripple surface or corrugated tubing may be used if required.

Claims (24)

195663 WHAT HE CLAIM IS:

1. A heat exchanger comprising: (a) a coiled tube of a plurality o£ turns each axially spaced apart from those turns adjacent having an inlet and an outlet for a first fluid to flow through the tube; (b) a conduit forming an inlet for a second fluid, the conduit being disposed to discharge the second fluid to impinge on the tube between turns of the coiled tube and substantially tangentially to a turn of the coiled tube; (c) an outlet from the heat exchanger for the second fluid; and (d) a wall which is substantially concentric with the said coiled tube and spaced slightly apart and outwardly therefrom, the wall being disposed relative to the said conduit to deflect the second fluid after discharge of the second fluid from the conduit into a flow path which substantially follows alongside the path of the turns of the coiled tube.

2. A heat exchanger as claimed in claim 1 wherein the said wall is a wall of a chamber in which the tube is coiled.

3. A heat exchanger as claimed in claim 2 wherein the coiled tube is wholly supported by a removable part of a wall of the 195663 chamber.

4. A heat exchanger as claimed in claim 3, wherein the chamber is substantially cylindrical in shape and the said 5 removable portion of a wall of the chamber is an end plate of the cylindrical chamber.

5. A heat exchanger as claimed in claim 2 wherein the conduit is arranged to deliver the second fluid into the chamber 10 substantially tangentially to a wall of the chamber.

6. A heat exchanger as claimed in any one of claims 2 to 5, wherein the chamber defines an annular space around the coils of the tube. 15

7. A heat exchanger as claimed in any preceding claim wherein the said coiled tube is substantially helical.

8. A heat exchanger as claimed in any one of claims 1 to 6 20 wherein said coiled tube is spiral.

9. A heat exchanger as claimed in claim 8 wherein the spiral is substantially conical. 1956*3

10. A heat exchanger as claimed in claim 8 wherein the spiral is dished in form.

11. A heat exchanger as claimed in any one of claims 8 to 10 two or more helices or spirals.

12. A heat exchanger as claimed in any preceding claim wherein there is a plurality of the said coiled tubes arranged 10 in parallel.

13. A heat exchanger as claimed in any preceding claim wherein baffles are arranged between turns of the coiled tube to assist the second fluid to follow the path of the tube. 15

14. A heat exchanger as claimed in any preceding claim wherein the coiled tube is non-corrugated.

15. A heat exchanger as claimed in claim 1 substantially as 20 herein described with reference to Figures 1 and 2 of the accompanying drawings.

16. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figure 3 of the 25 accompanying drawings. 5 wherein the coiled tube comprises a spiral tube coiled to form -17- 195663

17. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figures 4 and 5 of the accompanying drawings.

18. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figures 6 and 7 of the accompanying drawings. 10

19. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figures 8 and 9 of the accompanying drawings.

20. A heat exchanger as claimed in claim 1 substantially as 15 herein described with reference to Figures 10 and 11 of the accompanying drawings.

21. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figures 12 and 13 of the 20 accompanying drawings.

22. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figure 14 of the accompanying drawings. 5 25 18 / 195663

23. A heat exchanger as claimed in claim 1 substantially as herein described with reference to Figure 16 of the accompanying drawings.

24. A fluid storage container incorporating a heat exchanger as claimed in any one of claims 1 to 25. MICON ENGINEERING LIMITED by its authorised agents J.D. HARDIE AND CO. per: 10 15 20 25 -19-