EP0796418A1

EP0796418A1 - Combination of fan, heat exchanger and housing

Info

Publication number: EP0796418A1
Application number: EP95942787A
Authority: EP
Inventors: Augustinus Wilhelmus Maria Bertels
Original assignee: Helpman Intellectual Properties BV
Current assignee: Helpman Intellectual Properties BV
Priority date: 1994-12-22
Filing date: 1995-12-20
Publication date: 1997-09-24
Also published as: NL9402190A; TW311972B; WO1996019706A1; AU4401696A

Abstract

A combination of a fan (2), a heat exchanger (3) and a housing (4); which fan (2) comprises: a central hub (5); a plurality of blades (6) connected to this hub (5) and extending at least more or less in radial direction, which blades take a form such that when driven rotatably round the axis of the hub an air displacement occurs; drive means (10) for rotatably driving the blades with the hub round the axis of the hub, which heat exchanger (3) comprises: a plurality of hollow panels (13) placed at a mutual distance, for instance substantially parallel to each other, in one spiral form or substantially coaxially, through which panels (13) medium can flow, and which have a medium inlet (31) and a medium outlet (32); which housing (4) comprises: a casing (16) with a tubular passage in which the fan (2) and the heat exchanger (4) are placed such that air flow generated by the fan (2) flows through the spaces between the hollow plates for heat exchanging contact via the walls of these plates between the air in the air flow and the medium flowing through the hollow plates.

Description

COMBINATION OF FAN, HEAT EXCHANGER AND BOUSING

The invention lies in the field of thermal condi¬ tioning of air. A combination is known of a typical fan, a heat exchanger comprising fins and tubes, and a housing m which the fan and the heat exchanger are accommodated. An axial fan generates a more or less cylindrical air flow in which the a r particles move in a more or less helical path. As a result of this form of flow the known combination cf an axial fan and a heat exchanger of substantially square cross section nas the drawbacr. that particular parts cf the heat excnanger do not come into contact with the heat exchanger or only do so to a very inadequate degree. The efficiency of the known combina¬ tion hereby leaves something to be desired.

Due to the form of the known heat exchanger the air flowing therethrough is urged to move forward in a more or less straight line . As a consequence the kinetic energy corresponding with the rotation component in the helical flow is dissipated. This is an undesired effect, particularly m cooling systems. A corresponding side effect is tne occurrence of turbulences, swirl and noise production. These effects also reduce efficiency. They can moreover cause nuisance. It might be worth considering combining a known neat exchanger of square, at least rectangular cross section with a number of tangential fans. An axial fan is however recommended with regard to the possibility cf aerodynamic modelling of the blades cf an axial fan m order to obtain a very hign efficiency.

The invention has for its object to provide a combi- nation of a fan, a heat exchanger and a housing which combines a very hign efficiency with a very low noise production.

Anotner object cf tne invention is to provide such a combination which nas a vεrv simple construction and car. be manufactured relatively inexpensively. In respect of the above stated objectives the invention provides a combination of a fan, a heat exchanger and a housing; which fan comprises: a central hub; a plurality of blades connected to this hub and extending at least more or less in radial direction, which blades take a form such that when driven rotatably round the axis of the hub an air displacement occurs; drive means for rotatably driving the blades with the hub round the axis of the hub, which heat exchanger comprises: a plurality of hollow panels placed at a mutual distance, for instance substantially parallel to each other, in one spiral form or substantially coaxially, through which panels medium can flow, and which have a medium inlet and a medium outlet; which housing comprises: a casing with a tubular passage in which the fan and the heat exchanger are placed such that air flow generat¬ ed by the fan flows through the spaces between the hollow plates for heat exchanging contact via the walls of these plates between the air in the air flow and the medium flowing through the hollow plates. Very quick and easy to manufacture is a combination of the described type in which the hollow panels are embodied as one spirally wound hollow panel.

An embodiment with a low flow resistance has the special feature that the panels are or can be connected by at least one manifold to a medium conduit.

This embodiment can for instance have the feature that a manifold is embodied as a row of at least more or less aligned tubes which mutually join adjacent panels.

When a two-phase system is used, for instance in an evaporator, the liquid conduit can debouch in the lower parts of the heat exchanger, while the gas lines debouch in the upper parts thereof. The above described structure ensures that the force of gravity is effective in the operation of the system. Attention is drawn in this respect to the fact that CH-A- 146 950 relates to a heat exchanger wherein the manifolds extend horizontally so that in this prior art there cannot be any operation under the influence of the force of gravity.

R22, NH₃, alkanes, alcohols and other suitable liq¬ uids can for instance be considered as media for a two- phase system.

The combination preferably has the special feature that the liquid conduits have an effective diameter which differs by less than a factor of 2 from the effective average free distance between two mutually connected plates. This ensures a very high efficiency.

The latter variant can advantageously display the special feature that the said free distance amounts to 0.2-4 mm.

A very simple method for manufacturing a heat ex- changer which forms part of the above stated combination comprises the following steps, for performing in suitable sequence, of: laying metal plates, which are mutually connectable by welding, one on top of another in register; sealingly connecting these plates to each other by local spot welding over their whole surface and over both their longitudinal edge zones, for instance by roller welding; arranging medium connections on both end zones and sealingly connecting these plates to each other in these end zones, for instance by roller welding; plastically deforming the thus obtained panel such that it is modelled to a plurality of layers arranged at mutual distances, for instance forming into a zigzag or winding into spiral form of the thus obtained panel, while optionally making use of spacers placed between the resulting layers; admitting medium via at least one medium connection into the space bounded by the panel, which medium has a pressure such that the plates move apart under plastic deformation in the zones between the spot welds and the edge connections; and subsequently releasing the thus formed heat exchang¬ er.

The method according to the invention results in a heat exchanger having a very great rigidity and stability of form without the use of relatively thick plate materi¬ als being necessary.

The invention also relates to a heat exchanger obtained with this method.

The invention will now be elucidated with reference to the annexed drawings. Herein: figure 1 shows a partly broken away perspective view of a combination according to the invention in which for the sake of clarity the heat exchanger has been slightly shifted axially; figure 2 shows a view corresponding with figure 1 of a variant; figure 3 shows the heat exchanger of figure 1 on enlarged scale; figure 4 shows a perspective view of a combination according to the invention for use in association with a motorcar engine; and figure 5 shows a schematic, perspective view of an apparatus for manufacturing the heat exchanger according to figure 2. Figure 1 shows a combination 1 of a fan 2, a heat exchanger 3 and a housing 4. Figure 3 shows the heat exchanger according to figure 1 on enlarged scale.

The fan comprises a central hub 5 and eight aerody- namically formed blades 6 connected to this hub 5 and extending at least more or less in radial direction, which blades take a form such that when driven rotatably round the axis of hub 5 an air displacement occurs. The blades 6 are connected with their end zones 7 to a ring 8 which is driven by a motor 10 via a drive roller 9. The ring 8 is further guided by guide rollers 11,12 which are arranged spring-mounted in housing 4.

The fan 2 is described in applicant's patent appli- cation entitled "Fan" filed at the Netherlands Patent Office on the same day as the present application.

The heat exchanger 3 comprises a hollow panel 13 through which medium can flow and having a medium inlet 14 and a medium outlet 15. As shown clearly in figures 1 and 2, the hollow panel is wound into the shape of a spiral, wherein the overlying layers of the panel are ordered at roughly the same mutual distance. The layers thus have a free space between each other in which the more or less helically flowing air generated by the fan 2 can move in this helical form through the heat exchanger 3 in order to absorb heat from or relinquish heat to the thermal medium flowing through the medium connections 14,15 and the panel 13.

The housing comprises a casing 16 with a tubular passage 17 in which fan 2 and heat exchanger 3 are placed such that the air flow generated by fan 2 flows through the spaces between the layers of the hollow panel 13 for heat exchanging contact via the walls of this panel 13 between the air in the air flow and the medium flowing through the hollow panel 13.

Attention is drawn to the fact that, also in the central part of the air flow generated by the fan 2, heat exchanging contact is possible between this air flow and the heat exchanger 3. In contrast to known axial fans, the fan 2 has no relatively bulky central hub, as the hub 5 has negligible transverse dimensions. The generated air flow hereby has practically no "dead zone" in the central part. The heat exchanger 3 can be wound into the centre such that a good heat exchanging contact with the through-flowing air is also possible there. The combina¬ tion according to the invention hereby provides an addi¬ tional gain in space. Figure 2 shows a combination which largely corre¬ sponds with the combination of figure 1. At variance with figure 1, a medium inlet conduit 14 and a medium outlet conduit 15 are not used but the spirally wound layers lying over each other are connected by respective mani¬ folds, that is, a lower manifold 31 and an upper manifold 32. These manifolds are connected to the associated layers of the spirally wound hollow panel 13. Since in this embodiment the heat exchanger 3 is used as evapora- tor, the lower part of each winding of the spiral form contains liquid while the upper part contains gas or vapour. Manifolds 31 and 32 do not necessarily have to extend in vertical direction. It is important however that at least one of the manifolds debouches in the gas. Figure 4 shows a combination 34 in another embodi¬ ment. This comprises a fan 35, a heat exchanger 36 and a housing 37. The heat exchanger 36 comprises a spirally wound part 38 co-acting with the fan 35 and a part 39 extending in the shown zigzag form. This embodiment is suitable for use in association with motorcar engines. The form of the combination is adapted to the remaining available space in the engine compartment of a motorcar. The spiral-shaped part 38 can draw in for cooling the air 40 forced by means of the fan 35. The zigzag part 39 can allow passage of flow air during driving.

As in the embodiment of figure 2, use is made in the combination 34 according to figure 4 of manifolds 42,43 for respectively feeding and discharging cooling liquid for the engine. Figure 5 shows the manner in which the heat exchang¬ er 3 according to figures 1 and 2 can be manufactured.

Metal plates 20 and 21 which can be joined to each other by welding are unwound from rolls 18, 19 respec¬ tively such that these plates are placed with their longitudinal edges one on top of another in register.

By means of a schematically designated spot welding device 22 the plates 20,21 are mutually joined by spot welds distributed over their whole surface. Downstream of the spot welding device 22 the longi¬ tudinal edge zones 23,24 of plates 20,21 are joined sealingly by means of a roller welding device 25. After reaching a certain length the thus formed plates are severed by means of a cutting device 26 in order to form a subsequent panel. By means of means which are not drawn the panel delivered by the roller welding device 25 is wound to the shown spiral form. Use can optionally be made herein of spacers placed between the resulting layers. These spacers are not drawn.

The cutting device 26 is also adapted to sealingly connect together the transverse edge zones by welding in order to obtain closed end edges. See figure 2. These end edges are designated 27 and 28 respectively. In the manner indicated in figure 2 the medium connections 14,15 are arranged on the end edges 27,28. After the panel has been fully wound and is sealed in the manner described, medium can be admitted into the panel via one of these connections under a pressure such that the plates 20,21 move apart under plastic deformation in the zones between the spot welds 33 and the diverse edge connections such as the end edges 27,28 and the length¬ wise edges 29,30, whereby a cavity is created in the panel. After this operation the heat exchanger 3 is ready to form part of the combination according to figure 1. Attention is drawn to the fact that other forms of the heat exchanger are also possible within the scope of the invention. These are for instance a meander form, a zigzag form or a combination of different forms. The embodiment of figure 2 can be further modified by making use of coupled tube stumps between adjacent panel layers which are for instance mutually engaging, are welded to each other, are mutually joined by solder¬ ing, glueing, pinching or the like. An external connec- tion can be arranged at a position to be selected in the coupled tube stumps.

All embodiments with such a manifold have in common that the manifolds can also serve as spacer element. The invention enables the use of the very corrosion- resistant and inexpensive stainless steel as material for the heat exchanger instead of the usual combination of copper and aluminium. The thickness can amount for in- stance to (0.3 ± 0.2) mm. Due to this small thickness the steel sheet is very easily deformable and windable in the manner shown in figure 5. The heat exchanger obtained herewith is very compact and can withstand pressure well. At a thickness of 0.2 mm the resistance to pressure is for instance considerably higher than 25 bar.

The combination according to the invention has a wide range of possible applications. For instance con¬ densers, evaporators, car radiators. Such uses lie for instance in the temperature range of -30°C - +120°C. The combination according to the invention is free of prob¬ lems associated with thermal expansion, such as differen¬ tial expansion, which may result in fretting, leakages etc.

*****

Claims

X Sch/LR/Help-2CLAIMS

1. Combination of a fan, a heat exchanger and a housing; which fan comprises: a central hub; a plurality of blades connected to this hub and extending at least more or less in radial direction, which blades take a form such that when driven rotatably round the axis of the hub an air displacement occurs; drive means for rotatably driving the blades with the hub round the axis of the hub, which heat exchanger comprises: a plurality of hollow panels placed at a mutual distance, for instance substantially parallel to each other, in one spiral form or substantially coaxially, through which panels medium can flow, and which have a medium inlet and a medium outlet; which housing comprises: a casing with a tubular passage in which the fan and the heat exchanger are placed such that air flow generat- ed by the fan flows through the spaces between the hollow plates for heat exchanging contact via the walls of these plates between the air in the air flow and the medium flowing through the hollow plates.

2. Combination as claimed in claim 1, wherein the hollow panels are embodied as one spirally wound hollow panel.

3. Combination as claimed in claim 1, wherein the panels are or can be connected by at least one manifold to a medium conduit.

4. Combination as claimed in claim 3, wherein a manifold is embodied as a row of at least more or less aligned tubes which mutually join adjacent panels.

5. Combination as claimed in claim 3, wherein the heat exchanger is embodied as two-phase system, wherein liquid conduits debouch in the lower parts of the heat exchanger and gas lines debouch in the upper parts there¬ of.

6. Combination as claimed in claim 5, wherein the liquid conduits have an effective diameter which differs by less than a factor of 2 from the effective average free distance between two mutually connected plates.

7. Combination as claimed in claim 6, wherein the said free distance amounts to 0.2-4 mm.

8. Method for manufacturing a heat exchanger as specified in claim 2, comprising the following steps, for performing in suitable sequence, of: laying metal plates, which are mutually connectable by welding, one on top of another in register; sealingly connecting these plates to each other by local spot welding over their whole surface and over both their longitudinal edge zones, for instance by roller welding; arranging medium connections on both end zones and sealingly connecting these plates to each other in these end zones, for instance by roller welding; plastically deforming the thus obtained panel such that it is modelled to a plurality of layers arranged at mutual distances, for instance forming into a zigzag or winding into spiral form of the thus obtained panel, while optionally making use of spacers placed between the resulting layers; admitting medium via at least one medium connection into the space bounded by the panel, which medium has a pressure such that the plates move apart under plastic deformation in the zones between the spot welds and the edge joins; and subsequently releasing the thus formed heat exchang¬ er.

9. Heat exchanger obtained with the method as claimed in claim 5.