Heat exchange assembly

A heat exchange assembly such as for a solar roof comprises a pipe carried by a carrier plate and held thereto by suitable holding means. The carrier plate and/or the holding means have openings, each opening having a jagged edge portion projecting perpendicularly to the surface of the component in which it is formed. The jagged edge of each opening is partially embedded into the other component and material from that other component is engaged into the opening to form a rivet head-like configuration thereby to anchor the two components securely together.

BACKGROUND OF THE INVENTION 
Various kinds of heat exchange equipment are known, which include at least 
one heat exchange assembly comprising a conduit means for carrying a heat 
exchange fluid. The conduit means may be a pipe arrangement connected to a 
carrier member such as a metal plate or metal extrusion of suitable 
configuration, for receiving or giving off heat. The pipe arrangement may 
be held to the carrier member by clips or by one or more holding plate 
members which thus sandwich the pipe arrangement to the carrier member. 
Kinds of heat exchange equipment in which such assemblies are used include 
evaporators, in particular large-area units, solar panels, or solar roofs, 
i.e. a roof structure adapted to receive and utilise solar energy. 
A solar roof is proposed in French patent specification No. 2 330 794 
wherein, in a slightly different construction, the heat exchange medium is 
carried through passages provided in suitable extrusion plates or panels. 
However, extruded members of this kind are of relatively high weight, as 
well as being expensive. 
In another form of solar roof, for example as shown in DOS No. 27 02 939, 
the pipe arrangement is laid into curves or depressions formed in a sheet 
metal web or flat panel, and the web or panel is braced or deformed in a 
direction transverse to the axis of the pipe, thereby to grip the pipe. 
In yet another form of solar roof, the pipe is pressed into .OMEGA.-shaped 
grooves in the carrier plate. 
When the assembly comprises a pipe arrangement secured to a carrier member 
such as a plate, the pipe may be soldered or welded to the carrier plate, 
or, as mentioned above, connected to the plates by means of clips. In the 
latter case, the clips must be secured to the plate, for example by spot 
welding. However, welding or soldering are, in relative terms, very 
expensive operations, while there is also the danger that the pipe 
arrangement or the sheet metal web or plate which carries the pipe 
arrangement may be damaged in the welding or soldering operation. 
Furthermore, in such constructions, in which the pipe arrangement often 
only lies loosely against the carrier plate there is frequently only 
punctiform or linear contact between the pipe and the plate, so that the 
heat transfer between the carrier plate and the pipe is poor. 
It is therefore necessary in the previously disclosed constructions to 
tolerate either a low degree of heat transfer, or designs which are in 
relative terms very expensive. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a heat exchange assembly which 
provides for a good heat transfer between the heat exchange medium and the 
heat receiving or emitting portion of the system. 
A further object is to provide a heat exchange assembly which is of 
inexpensive design while also being suitable for mass production. 
A still further object of the invention is to provide a heat exchange 
assembly wherein a pipe or pipes for carrying a heat exchange medium is or 
are firmly but simply connected to a carrier member. 
These and other objects are achieved by a heat exchange assembly for use 
for example in a solar roof, a large-area evaporator or other form of heat 
exchange arrangement, wherein a pipe or pipes for carrying a heat exchange 
medium is or are connected to a carrier member which may be in the form of 
a metal plate or an extrusion, by holding means in the form of one or more 
clips or auxiliary holding plates. The carrier member and/or the clips or 
holding plates are provided with through openings whose edges project 
substantially normal to the surface of the carrier member and are of a 
frayed, jagged or ragged configuration, herein referred to for brevity as 
jagged. The jagged edges of the openings are pressed into the co-operating 
component, that is to say, when the openings are formed in the carrier 
member, then the edges of the openings are pressed into the clips or 
holding plates, and vice-versa. The holes are thereby filled with an 
anchoring portion of rivet-head-like configuration, caused by material of 
the above-mentioned co-operating component flowing into the opening. 
Where the pipe or pipes extend in a meander configuration or have at least 
a plurality of portions which extend generally parallel to each other, the 
openings may be formed in rows between the generally parallel-extending 
pipe portions. The carrier member and/or the clips and/or the holding 
plates may have curved portions forming recesses into which the pipe or 
pipes fit, thereby being even more securely located in position. 
The carrier member or plate may have a bent edge portion forming a 
connecting flange with a plurality of the above-mentioned openings 
therein, for securing the carrier member to a respective adjacent carrier 
member to be secured thereto to form a larger heat exchange assembly. It 
is possible for the components which have the openings to be harder, for 
example of a harder material, than the other components co-operating 
therewith. For example, the carrier member or plate, or the clips or 
holding plates may comprise aluminium, an aluminium alloy, copper or a 
copper alloy, any component of such material therefore not generally 
having openings but the openings instead being provided in the other 
component which is co-operable therewith. 
The carrier member or plate is therefore connected to the clips or 
auxiliary holding plates for holding the pipe in place by means of the 
above-mentioned openings with jagged edges. It will be appreciated that it 
is not simply a matter of punching out holes in order to produce the 
above-mentioned openings. On the contrary, holes are pierced or punched in 
the material of the component in such a way that no material is lost, 
whereby the material which is displaced in order to form the hole also 
forms frayed or jagged edges which project from the surface of the 
component substantially perpendicularly thereto. When a component with 
openings of this kind is pressed on to another component, the jagged edges 
around the openings press into the other component. As the above-mentioned 
edges press into the material of the other component, they cause the 
material to be displaced and urged towards the centre of the opening so 
that the displaced material forms an anchoring means of rivet head-like 
configuration in the opening. The openings may be economically produced by 
needling rollers, that is to say, rollers bearing a multiplicity of 
needles which, when the roller is rolled over the surface of the component 
in which the openings are to be formed, punch through the material of that 
component and thereby form the holes with jagged edges.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference will first be made to FIG. 1 which shows a heat exchange assembly 
comprising a carrier member in the form of a sheet metal web portion or 
plate 1 and an auxiliary holding plate 2. One or more rows of openings 3 
is formed in at least one of the plates 1 or 2, for the purposes of 
connecting the two plates 1 and 2 together. The openings 3, as referred to 
hereinbefore, have frayed or ragged or jagged edges which project at least 
substantially perpendicularly from the surface of the plate in which they 
are formed, for purposes which will become clear hereinafter. 
To assemble the assembly shown in FIG. 1, a pipe 4 is laid into curved 
recesses or depressions 6 formed in the plate 2. The two plates 1 and 2 
are then pressed together with the pipe 4 therebetween, thus resulting in 
a long-lasting and permanent `cold-made connection` between the two 
plates. Similar depressions to 6 may be formed in the plate 1, 
alternatively or in addition. 
Reference should be made at this point to FIG. 6 which shows on a larger 
scale the effect of the jagged edges of the openings 3 when the two plates 
1 and 2 are pressed together. It will be appreciated that the openings 3 
are made not just by punching or stamping out holes, which implies that at 
least a substantial part of the material which lay within the outline of 
the respective hole is lost by virtue of the punching or stamping 
operation. On the contrary, the opening 3 shown in FIG. 6 is produced by 
piercing or stabbing holes in such a way that the edge portion 8 thereof 
is torn upwardly (as viewed in FIG. 6), thereby forming jags or ragged 
edges which project at least approximately perpendicularly from the 
adjacent surface of the plate (this being the plate 2 as shown in FIG. 6). 
When now the jagged portions 8 engage into the material of the plate 1 
when the plates 1 and 2 are pressed together, the jagged portions 8 
displace and urge the material of the plate 1 towards the central part of 
the opening 3; under the effect of the pressing force applied in the 
direction indicated by arrows 9, the material of the plate 1 which has 
thus been caused to flow into the opening 3 is formed into a rivet 
head-like configuration 10 which provides a strong anchoring action. 
The pressing operation may be performed in a stationary press or by means 
of a moving tool or in a roller press through which the plates 1 and 2 are 
passed. By arranging for the press dies or pressing members to be of a 
suitable configuration, or by a suitable arrangement of the rollers which 
engage the plates 1 and 2 to press them together, it is possible to 
provide that the pressing force acts only on the rows of openings 3. This 
has the advantage therefore that, when producing the assembly, neither the 
raised portions 6 formed by the pipe or pipes 4 lying in the corresponding 
recesses in one or both of the plates 1 and 2, nor the pipe 4 itself, are 
deformed in such a way that the flow of heat exchange medium through the 
pipe arrangement 4 would be prevented or restricted. On the other hand, it 
is desirable for the cross-sectional area of the raised portions 6 to be 
somewhat less than the cross-sectional area of the pipe 4, or, in other 
words, for the raised portions 6 to be approximately of semicircular 
cross-section, as shown in FIG. 1. The effect of this is that, when the 
plate 2 is pressed on to the plate 1, the pipe 4 is slightly deformed, 
thereby forming a corresponding close-contact surface by way of which the 
pipe is pressed against the plate 1; in addition, a corresponding tensile 
stress is produced in the plate 1 between the rows of openings 3, the 
tensile stress causing the raised portions 6 to be pressed smoothly and 
firmly against the surface of the pipe 4. This results in a uniformly good 
degree of heat transfer between the plate 1 or the plate 2 and the surface 
of the pipe 4 and accordingly the heat exchange medium which circulates 
within the pipe 4. 
The openings 3 are preferably of a diameter, in consideration of the 
thickness of the plate 1, such that the ragged or jagged edges 8 which are 
pressed out of the plane of the plate 1 are somewhat less in height than 
the thickness of the plate 1, as clearly visible in FIG. 6. This ensures 
that the surface of the plate 1 remains unchanged and generally undeformed 
outside of the openings 3. However, even if the diameter of the openings 3 
is made somewhat larger so as to result in correspondingly ragged or 
jagged edge portions 8 of greater height, which could also have the result 
of deforming the plate in the region around each opening, practical use 
has shown that the tips of the jagged portions 8 are pressed flat in the 
pressing operation, in other words, even if the jagged portions 8 project 
to a substantial height above the surface in which they are formed, they 
are reduced to a satisfactory height of projection by the pressing force, 
and any deformation of the plate around each opening also tends to be 
removed by the pressure. Although it can then be seen, on the surface of 
the plate 1 which is remote from the plate 2, that a machining or 
processing operation has been effected, that surface of the plate is still 
continuous and generally undamaged. 
Reference will now be made to FIG. 2 which shows that the openings 3 are 
also suitable for connecting a plurality of carrier plates 1 together. As 
is generally conventional procedure nowadays in the manufacture of sheet 
metal roofs, the carrier plates 1 may have edge portions 7 which are bent 
out of the plane of the plate 1 so as to extend perpendicularly to the 
main body portion of the plate 1. The plates 1 are water-tightly connected 
together by the adjoining edge portions 7 of the pair of plates 1 being 
beaded or flanged over one or more times. Continuous or continuously 
moving tool arrangements may be used for this purpose. As shown in FIG. 2, 
the arrangement disclosed therein provides that one or more rows of the 
openings 3 as defined above can now be provided in the edge region 7 of at 
least one of the two plates to be joined together. The perpendicular edge 
regions 7 can be substantially shorter if required. The edge regions 7 are 
secured together by pressing them together by means of a continuous tool 
and, if required, by subsequent beading or flanging over. It will be 
appreciated that a wide range of connecting operations which are required 
in the production of a roof or a solar roof, can be carried out in the 
same or a similar manner to that shown in FIG. 2. This includes the 
production of gutter terminations, ridge fixings, side seals or closures, 
ducts or lead-through means for chimneys or vents, seals or closures on 
dormer windows or skylights and the like. The respective closure and 
connecting members then have one or more rows of the above-mentioned 
openings 3, at an appropriate position, or connecting members such as 
clips may be secured in place by means of the above-mentioned openings 3. 
This makes it possible to extensively eliminate expensive welding or 
soldering operations. 
Reference is now made to FIG. 3 which shows that the curved portions or 
depressions 6 in the holding plate 2 can be omitted (see also FIG. 4 
showing that the plate 2 may be flat prior to being pressed). It is even 
unnecessary for the holding plates 2 to be of the same width as the 
carrier plates 1. Therefore, the plates 2 may simply be strip members 
which are secured to the carrier plate 1 by means of openings 3, the 
purpose of the plates 2 then being primarily to hold the tube arrangement 
4 in position and press it against the plate 1. The plate 2, of whatever 
form, may also have jagged-edge openings which are pressed out of the 
plate alternately in one direction and the other. In this way, shaped 
members 11, for example, as shown in FIG. 3, members of a generally 
Z-shaped, U-shaped or T-shaped configuration, may be simultaneously 
secured in a single pressing operation to the plate or plates 2. Shaped 
members 11 of this kind may be provided for supporting and securing the 
heat exchange members or assemblies, for example on a roof rafter or joist 
as indicated at 12. 
FIG. 4 shows the components provided for making a heat exchange assembly, 
before they are pressed together, that is to say, before the plate 1 is 
connected to the plate 2 which in this embodiment is provided with the 
jagged-edge openings 3. FIG. 5 shows the heat exchange assembly in its 
finished form, that is to say, after the pressing operation, whereby the 
jagged edge portion 8 of the opening 3 has been caused to be embedded in 
the material of the plate 1, with consequent flow of the material thereof, 
as shown in FIG. 6 and as referred to hereinbefore. 
FIG. 7 shows in diagrammatic form that, instead of the auxiliary holding 
plate or plates 2, it is possible to use various kinds of clips 5a to 5d 
with corresponding jagged-edge openings 3, with the clips 5a to 5d being 
of greater or smaller size, as required. The clips may be fitted over just 
a single run or limb of the pipe 4, or they may cover a plurality of such 
runs, as can be clearly seen from FIG. 7. FIG. 7 also shows that there are 
many possible variations in the structure of the invention, depending on 
the heat transfer required, the strength required, and also the specific 
construction involved. 
The above-described method of connecting the components, in a cold 
condition, by means of the jagged-edge openings 3, therefore has the 
particular advantage that on the one hand, the cost of securing the pipe 4 
to the carrier plate 1 is relatively low, but on the other hand, it is 
also possible to achieve a highly satisfactory heat transfer effect. There 
is therefore no need, to a very substantial extent, for expensive 
soldering or welding operations or other fixing methods. 
A particularly important consideration in this respect is that the 
above-described structure according to the invention makes it possible to 
solve corrosion problems which are an important factor specifically in the 
case of solar roofs. If, in the case of known roofs wherein it has not 
been possible to avoid soldering or welding, moisture manages to penetrate 
into the roof structure and such moisture is acid-enriched with for 
example sulphuric acid, as may happen in particular in large towns and 
cities and in industrial areas, then galvanic elements which result in 
corrosion are formed by virtue of the different levels of potential of the 
sheet metal plate 1, the soldering material, the material of the pipe 
arrangement, and the like. However, materials such as aluminium or 
aluminium alloys which are able to withstand such corrosion, while also 
being relatively inexpensive, are difficult to solder or braze. As the 
cold-connecting procedure as described hereinbefore only gives rise to 
minor problems, in respect of hardness, that is to say, the component 
which has the jagged-edge openings should be harder than the other 
components to be connected thereto, and as these problems can be solved by 
selecting a suitable material or alloy, the structure according to the 
invention provides the advantage that the limitations in respect of the 
material selected for use are substantially eliminated, while also 
avoiding problems from the point of view of corrosion. If materials of the 
same hardness, for example the plates 1 and 2, are to be connected 
together, it is preferable to use an insert strip 20, as illustrated in 
FIG. 9 which is harder than the metal of the plates 1' and 2' and which 
has jagged-edge openings as indicated at 3, with edge portions 8' pressed 
out of the strip alternately towards both sides thereof. Another suitable 
alternative for forming the connection shown in FIG. 2 is for a U-shaped 
strip member to be fitted in a hood-like manner over the upright edge 
portions of the carrier plates 1 (see FIG. 2); the strip member has 
jagged-edge openings which are pressed into the above-mentioned upright 
edge portions. 
Finally, reference should be made to FIG. 8 which shows a construction 
wherein the pipe 13 is provided with at least one laterally projecting 
portion 14, there being two such portions 14 as illustrated, on respective 
sides of the pipe. Each portion 14 has at least one opening 15, of the 
kind described above, with jagged or frayed edges, for securing the pipe 
to the carrier plate 1. The pipe 13 and portion or portions 14 are 
preferably integrally formed as by extrusion, and the or each portion 14 
may extend over the entire length of the pipe 13, although the or each 
portion may extend over only a part of the pipe length; in particular, the 
portion 14 may be removed as by cutting away, at locations where the pipe 
13 may be required to bend on its run on the carrier plate 1. It will be 
appreciated that in the FIG. 8 structure, the surface of the pipe 
13--portion 14 assembly, which is towards the adjacent surface of the 
plate 1 is at least substantially flat in order to provide good contact 
with the plate 1 for satisfactory heat-exchange therewith. 
In a modified form of the FIG. 8 embodiment, the openings 15 may be 
provided in the carrier plate 1 instead of the portions 14 as illustrated, 
the relative hardnesses of the interconnected components being suitably 
adjusted to give a good securing action. 
Various modifications may be made in the above-described embodiments of the 
invention without thereby departing from the spirit and scope thereof.