GB2195710A - Integrated heat exchanger and pump - Google Patents

Abstract

In order to overcome the problem of providing an external pump for circulation of a primary fluid in a heat exchanger the pump is incorporated into the heat exchanger housing to form a single unit. The impeller blades 28 of the pump interleave with fins 30 acting as heat exchanger surfaces to give a better heat transfer rate due to the high velocities associated with the rotation of the impeller blades in the region of the heat exchanger surfaces. The pump which has an axial inlet (14) and a radial outlet (16) is driven by a shaft 20. The secondary fluid flows in conduits 38 received in holes (36) of the fins. <IMAGE>

Description

SPECIFICATION Integrated pump and heat exchanger The present invention relates to an integrated pump and heat exchanger apparatus, and is intended for use, for example, in a refrigeration system.

In most heat exchanger systems exchanging heat between two fluids, one or both fluids are pumped through a heat exchanger by a pump connected thereto by a pipework or ducting system. The pumping function is thus separated from the heat exchange function.

There are various disadvantages with the present systems in that separate mounting surfaces for each heat exchanger and. pump have to be provided, that each heat exchanger and pump would require individual sealing, and that the cost is relatively high.

There is also problem associated with some of the existing pump and heat exchanger arrangement, for example, in a refrigeration system where a frost layer build up occurs on heat exchange surfaces of the heat exchanger.

A complicated defrosting system has to be provided to defrost the surfaces periodically so that the efficiency of the system is not adversely effected.

The present invention seeks to integrate the pump and the heat exchanger of the kind specified in a simple and convenient form.

According to the present invention an integrated heat exchanger and pump unit comprises a heat exchanger housing having a pr mary circuit and a secondary circuit, and a pump for inducing flow of a primary circuit fluid, the pump having blades which interleave with heat exchange surfaces.

By way of example, some embodiments of the invention will now be described, with reference to the accompanying diagrammatic drawings of which, Figure 1 is an end view of an integrated pump and heat exchange constructed in accordance with the invention.

Figure 2 is a side view in section of the combined pump and heat exchanger illustrated in Fig. 1.

Figure 3 is an end view of another embodiment of the invention.

Figure 4 is a side view in section of the combined pump and heat exchange illustrated in Fig. 3.

Figure 5 is a similar view to Fig. 3 but shows a conduit in a different shape.

Figure 6 is a plan view of the first stage of manufacture of an impeller for use in Fig. 1 and Fig. 3 inventions.

Figure 7 is a part view of the formed impeller.

Figure 8 is another form of an impeller, for use in Fig. 1 and Fig. 3 inventions.

Figure 9 is a further form of impeller for use in Fig. 1 and Fig. 3 inventions.

Figure 10 is a side view in section of another embodiment of the invention.

Figure ii is a schematic section along the line X-X on Fig. 10.

Figure 12 is a part view of an impeller for use in Fig. 10 invention.

Figure 13 is a partial view of an inter-leaving between an impeller arm and circular fins for use in Fig. 10 invention.

With reference to Figs. 1 and 2 of the drawings, an integrated pump and a heat exchanger unit 10 include a heat exchanger housing 12 with a primary axial fluid inlet 14 and a primary fluid outlet 16.

A pump 18 with drive member 20 is arranged centrally and longitudinally in the housing 12. A drive means 22 connected to member 20 provides the rotation for the pump 18.

The drive means 22 can either be external or within the housing 12. A tubular member 24 is co-axially arranged with the drive member 20 and is connected by plates 26 to the drive member. Slots 21 are provided on the plate 26 to allow the primary fluid between the tubular member 24 and the drive member 20.

The pheriphery of the tubular member 24 has a plurarity of blades 28 extending evenly there from to form an impeller and plurarity of these impellers are arranged in side by side relationship on the pheriphery and along the length of the tubular member 24 as shown in Fig. 2.

Interleaved between the impellers are fins 30.

Each fin 30, representing a heat exchange surface, is in a form of a circular plate 32 with a hole 34 and plurarity of projections 33 evenly distributed on the pheriphery of the circular plate.The hole 34 is larger in diameter than the tubular member 24. Each projection 33 has a tubular hole 36 therein to receive a secondary fluid conduit 38, perpendicular to the plate 32. Each seciondary fluid conduit 38 may be bonded or expanded onto the plate 32 for location and thermal contact. The plate 32 thickness is chosen so that the fin 30.

efficiency is adequately high.

The impeller blade 28 tips are arranged to extend beyond the pheriphery of the circular plate 32 as shown in Fig. 1, the reason for this will become apparent latter in the description.

For ease of assembly, the housing 12 is split diametricaly and end plates (not shown) are provided to secure the housing together.

In use the drive means 22 rotates the pump 18. The rotation of the pump forces the primary fluid, from the primary axial inlet 14 into the housing 10 via passages (not shown) on tubular member 24 and out through the primary outlet 16. As the primary fluid passes through the housing 12 the heat is transfer to the secondary fluid in the secondary fluid conduit 38. The transfer of heat from the primary fluid to secondary fluid occur through the fin 30 which is in thermal contact with the secondary fluid conduit 30, and also by the sur rounding primary fluid around the conduit 30.

Although six secondary conduit 38 are shown, the number of conduit 38 will vary depending on the type of application.

With reference to Figs. 3 and 4 of the drawings, an integrated pump and heat exchanger unit 40 includes a heat exchanger housing 42 with a primary fluid inlet 44 and a primary fluid outlet 46.

A pump 48 with a drive member 50 is arranged centrally and longitudinally in the housing 42. A drive means 52, connected to member 50, provides rotation for the pump 48. The drive means 52 can either be external or within the housing 42. A tubular member 54 is co-axially arranged with the drive member 50 and is connected by plates 56 to the drive member 50. Slots 51 or holes are provided on the plate 56 to allow the primary fluid between the tubular member 54 and the drive member 50. The pheriphery of the tubular member 54 has a plurarity of blades 57 extending evenly there-from to form an impeller and plurarity of these impellers are arranged in side by side relationship on the pheriphery and along the length of the tubular member 54 as shown in Fig. 4.

Also forming part of the housing 42 is an inlet manifold 58 and an outlet manifold 60.

The inlet manifold 58 has connected to it a secondary fluid inlet conduit 62 and the outlet manifold 60 has connected to it a secondary fluid outlet conduit 64. The two manifolds 58 and 60 are preferably arranged at opposite ends of the housing 42. A plurarity of secondary tubular conduits 66, representing heat exchange surfaces, extend from one end of the inlet manifold 58 to the outlet manifold 60.

The conduits 66 are transversely arranged in side by side relationship on either side of the central rotating axis of the pump 48 and interleaved between the adjacent impellers.

In use, the drive means 52 rotates the pump 48. The rotation of the pump 48 forces the primary fluid to flow in from the primary inlet 44 into the housing 42 via passages (not shown) in tubular member 54 and out through the primary outlet 46. The secondary fluid flows from the secondary inlet 62 into the inlet manifold 58 through the conduits 66 and into the outlet manifold 60 and exists through the secondary fluid outlet 64.

As the primary flow passes through the housing 42 the heat is transferred to the secondary fluid as it passes through the conduit 66.

Although six secondary conduits 66 and four impellers 59 are shown, the number of conduits and impellers can be varied to suit particular type of application.

It is possible that the conduit 66 can be shaped such that a larger section of the conduit 66 is swept by the impeller without affecting the geometry as shown in Fig. 5.

For ease of assembly, the housing is split diametrically and end plates (not shown) are provided to secure the housing 42 together.

It is possible when either of the arrangements described are used, for example, in a refrigerator system that first build-up occurs on the heat exchanger surface ie the conduit 66 in Fig. 4 or the fin 30 in Fig. 2. The present arrangements have an added advantage in that by controlling the clearance between the impeller blade 28 and the fin 30 or between the impeller blade 57 and the conduit 66 any deposited material such as fouling or frosting will be substantially eliminated owing to the continual wiping action of the impeller.

In some applications it may be advantageous for continuous contact to be made between the impeller blade 28 and the fin 30 or between the impeller blade 57 and the conduit 66. With the above arrangements described, the need for providing periodic defrosting system are eliminated.

The tips of the impeller blades 28 in Fig. 1 and the tips of the impeller blades 57 in Figs.

3 and 4 can be arranged to extend beyond the pherpiphery of the circular plate 32 in Fig.

1 or beyond the conduit 66 in Fig. 4 to avoid any possible bridging action of the fouling or the frost layer.

A number of different types of impeller can be used and manufactured for the arrangements just described. A first type of impeller partly shown in Fig. 7 can be manufactured by using a single rectangular sheet 100, as shown in Fig. 6, of an appropriate size. A series of transversely extending cuts 102 are made in the sheet. Each series is provided with a plurarity of cuts 104 for forming the impeller blades. The individual cuts are bent up, away from the sheet 100, to form the blades 28, 57 as shown in Figs. 2 and 4. The sheet 100 is then wrapped up by connecting the two transverse edges of the rectangular sheet to form the impeller.

A second type of impeller as shown in Fig.

8 can be made by using a circular shaped disc 106 with a centre portion. 108 of the disc removed and holes 110 formed for linking to a drive member. A plurarity of louvred blades 112 are connected to the disc to form the impeller.

A third type of impeller partly shown in Fig.

9 can be made by using a circular disc 114 with a centre portion 116 of the disc removed and holes 118 formed for linking to the drive member. A plurarity of equal radical segments are removed. The remaining portion 120 of the disc 114 are twisted and bent to form impeller blades 121.

With reference to Figs. 10 and 11 of the drawings, a half-view of an integrated pump and heat exchanger unit 70 is shown. A cylindrical heat exchanger housing 72 include a primary fluid inlet 74 and a primary fluid outlet 76. A pump 78 comprises a drive member 80 and an impeller 84. The drive member 80 is connected to a drive means 82. The drive member 80 is centrally and longitudinally arranged in the housing and the impeller 84 is perpendicularly connected to the drive member 80.

One of a plurarity of tubular fins 85 of different diameter are co-axially placed in the housing 72 with equal radial separation as shown in Fig. 11. A plurarity of secondary conduit 88 are positioned radially from the pheriphery of the housing 72 and pass through holes 86 in the tubular fins 85. The conduits 88 are equi-spaced on the circumference of the housing 72 and are in the same place. Each conduit 88 protrude slightly beyond a smallest tubular fin. Four adjacent conduits 88 with curved portions 89 and a curved portion 90 forms one complete secondary fluid flow circuit. The free ends of the two outer conduits of the circuit, at the pheriphery end of the housing 72, define a secondary fluid inlet 91 and a secondary fluid outlet 92. The inner free ends of the four conduits 88 adjacent the smallest tubular fin 85 are joint by two curved portions 89.The two free ends of the inner conduits of the circuit, at the pheriphery end of the housing 72, are joint by a curved portion 90.

Although a number of secondary flow circuits are shown, it is possible to form a single secondary flow circuit. The adjacent inlet 91 to the outlet 92 can be joint together by a curved portion 90 except for one which will form the inlet and outlet for the secondary flow.

The impeller 78 consists of a circular disc 93 better seen in Fig. 12 and has a set of extending arms 94 regularly spaced around the perimeter.

A leading edge of the arm 94 has a series of impeller blades 95, in a form of an arc, in side by side relationship. The arc length of each blade is such that after the arm has been twisted, see Fig. 13, all tips of-the blades lie in the same place. When the impeller 78 is connected to the drive member 80, the impeller blades 95 are in an axial direction to the housing 72. The blades 95 also interleaves with the tubular fins as shown in Fig. 10 and Fig. 13.

Each blade 95 are also of such a length that a small clearance exist between the tip of the blade and the secondary fluid conduit 88.

The drive means 82 can be mounted within the innermost fin. This has a potential advantage in that the whole arrangement takes up very little axial space and consequently the housing 72 can be made very compact.

In use, the drive means 82 rotates the pump 78. The rotation of the pump 98 forces the primary fluid to flow in from the primary inlet 74 into the housing 72 and out through the primary flow outlet 76. The secondary fluid flows through the secondary inlet 91 and out through the outlet 92.

As the primary flow passes through the housing 72 the heat is transferred to the secondary fluid. The transfer of heat from the primary fluid to secondary fluid occurs through the tubular fins 84 which are in thermal contact with the secondary fluid conduits 88.

It is again possible when the arrangement described is used, for example, in refrigerator system that frost build-up will occur on the heat exchange surface on the fins 84. By allowing a small clearance between the axial impeller blade 90 and the fin 84, any deposited material such as fouling or frosting will be substantially eliminated due to the whole surface of each fin being swept by the axial impeller blades 95.

The present embodiment described has added advantage in that two or more of pump and secondary fluid flow conduits can be installed in series in the heat exchange housing 72.

It should be understood that the primary and secondary fluid in all embodiments may be in liquid, gaseous or mixed state. It is also possible in all the embodiments described that the blades are fitted with a flexible material which can press lightly against the heat exchange surface. Any deposits, such as condensation of frost, on the heat exchange surface can thereby be removed continuously and rapidly during the pump rotation.

It will be realised in all the embodiments that due to the impeller blades being in thermal contact with the heat exchange surfaces, the rate of heat transfer from the primary fluid to secondary fluid is increased than in a conventional system by virtue of high surface velocities associated with the rotation of the impeller blades in the region of heat exchange surfaces.

A further application of the present invention is in a field of bireactor vessel, where a function of mixing, oxygenation and heat transfer are all combined. With such an application, oxygen can be introduced into the primary circuit, preferably upstream of the heat exchange surface and the pump, at appropriate points in order to achieve event distribution with the primary circuit fluid. Further distribution and mixing of oxygen with the primary circuit fluid will be achieved by the heat exchange surface interleaving with the impeller blades during the pump rotation.

Claims (21)

1. An integrated heat exhanger and pump unit comprising a heat exchanger housing having a primary circuit and a secondary circuit, and a pump for inducing flow of a primary circuit fluid, the pump having blades which inerleave with heat exchange surfaces.

2. An integrated heat exchanger and pump unit according to Claim 1 in which the pump has a drive member connected to a drive means, a tubular member co-axially arranged with the drive member, a pheriphery of the tubular member having a plurality of blades extending evenly therefrom to form an impeller, and plurality of these impellers are arranged in side by side relationship along the length of the tubular member.

3. An integrated heat exchanger and pump unit according to Claim 2 in which at least one plate interconnect the tubular member tq the drive member.

4. An integrated heat exchanger and pump unit according to any one of the preceding claims in which the heat exchanger surface is a fin or fins which is connected to a secondary fluid conduit or conduits through which the secondary circuit fluid flow.

5. An integrated heat exchanger and pump unit according to Claim 4 in which each fin is in a form of a ciruclar plate with a hollow aperture and a plurality of projections distributed on the pheriphery of the circular plate, each projection being provided with an aperture to receive the secondary fluid conduit in thermal contact.

6. An integrated heat exchanger and pump unit according to Claim 5 in which the secondary fluid conduit is perpendicular to the fin and extend through the heat exchanger housing.

7. An integrated heat exchanger and pump unit according to Claims 4 and 5 in which the impeller blade tip extends beyond the pheriphery of the circular plate of the fin.

8. An integrated heat exchanger and pump unit according to Claims 1-3 in which the heat exchanger surface is a secondary fluid conduit through which the secondary circuit ffuid flow.

9. An integrated heat exchanger and pump unit according to Claim 8 in which the housing has an inlet manifold and an outlet manifold which are arranged at opposite ends in the housing and plurality of secondary fluid conduits extend between the inlet and outlet manifolds.

10. An integrated heat exchanger and pump unit according to Claim 9 in which each secondary fluid conduit is transversely arranged in side by side relationship on either side of a rotating axis of the pump.

1-1. An integrated heat exchanger and pump unit according to Claim 10 in which the impeller blade tip extends beyond the secondary conduit.

12. An integrated heat exchanger and pump unit according to Claim 1 in which the heat exchanger housing is in a cylindrical form, the pump having a drive member co-axial with a drive means and an impeller connected to the drive member, the impeller comprising of a circular disc with a set of extending arms regulariy spaced around a perimeter of-the circular disc and one side of each arm having a series of impeller blades, in a form of an arc, in side by side relationship.

13. An integrated heat exchanger and pump unit according to Claim 12 in which each arc lenght of impeller blade on each arm is such that when the arm of the impeller is twisted, the impeller blade tips all lie in the same plane and that the impeller blades are in an axial direction to the housing.

14. An integrated heat exchanger and pump unit according to Claims 12 and 13 in which the heat exchanger surface is a fin which is connected to a secondary fluid con duit through which the secondary circuit fluid flow.

15. An integrated heat exchanger and pump unit according to Claim 14 in which each fin is in a tubular form with different diameter and these fins are co-axially posi tioned in the housing with radial separation.

16. An integrated heat exchanger and pump unit according to Claim 15 in which plu rality of secondary fluid conduits are posi tioned radially and in the same plane from the pheriphery of the housing, each secondary fluid conduit passing through holes formed on on the fins and protuding slightly beyond a smallest tubular fin.

17. An integrated heat exchanger and pump unit according to Claim 16 in which four adjacent secondary fluid conduits form one complete secondary flow circuit where the free ends at the pheriphery of the housing of the outer secondary conduits form a secon dary inlet and outlet, the free ends of the inner secondary conduits at the pherpiphery of the housing are jointed together by a curved portion and the free ends of the outer and an adjacent secondary conduits adjacent the smallest tubular fin are joined together by a further curved portions.

18. An integrated heat exchanger and pump unit according to Claim 17 in which there is a clearance between the tips of the impeller blades and the secondary fluid condu its during the pump rotation period when the tips of the blades are adjacent to the secon dary fluid conduits.

19. An integrated heat exchanger and pump unit according to any one of the pre ceding claims in which the primary and secon dary fluids many be liquid, gaseous or mixed state.

20. An integrated heat exchanger and pump unit according to any one of the pre ceding claims in which the impeller blades are fitted with a flexible material such that the flexible material presses against the heat ex changer surface to remove any deposits dur ing the pump rotation.

21. An integrated heat exchanger and pump unit substantially as described herein with reference to Figs. 1, 2, 6-9 or Figs. 3-9 or Figs. 10-13.