The present invention relates to a slider device for a solar heat collector assembly and the use thereof in a solar heat flat panel collector incorporating such device.

More particularly, the invention relates to a method and means for the slidable suspension of a solar heat collector assembly, wherein manifold ends of the solar heat collector assembly are supported by walls of a flat panel collector casing in slider brackets, which allow for thermal expansion and contraction of the heat collector assembly. PCT/ZA2011/000006 (and likewise equivalent ZA 2011/00688) by the same inventors as the present invention proposes such a suspension and its use in a solar heat flat panel collector and a solar heat flat panel collector including such suspension.

Expressed differently, the invention relates to a solar heat collecting device of the flat panel type, including a panel casing defined by an upper side which provides a window area for facing and admitting incoming solar radiation, surrounding walls forming a frame between the upper side and a closed underside opposite to the upper side, a heat collector assembly accommodated inside the panel casing, the heat collector assembly being formed by a heat absorption area facing the window area and having passage formations in heat exchange relationship with the heat absorption area for a heat carrier medium flowing through the passage formations between manifolds at opposite ends of the heat absorption area, including a manifold end member of an aforesaid manifold passing through a wall of the casing by way of a slider bracket associated with an aperture through that wall and which provides slidability to the manifold end member transversely to the wall to allow for thermal expansion and contraction of the heat collector assembly. More particularly, in accordance with PCT/ZA2011/000006, the heat absorption area and passages of the heat collecting assembly are provided by a plurality of elongate heat collector bodies extending side-by-side, each providing a heat absorption area facing the window aperture area and a tubular cavity for accommodating a flow of heat carrier fluid between manifolds at opposite ends of the elongate collector bodies; an inlet for admitting, in order to be heated, a heat carrier fluid to the heat collector assembly; and an outlet for withdrawing heated heat carrier fluid from the heat collector assembly, wherein the elongate heat collector bodies are each formed as an integrally extruded aluminium or aluminium alloy profile, comprising said tubular cavity in the form of a tube extending continuously in the extrusion direction of the profile and, integrally extruded with the tube on each of the opposite sides of the tube, a web having a side facing the window aperture area, the webs on opposite sides extending from the tube at an angle to one another of between 170° and 190°, the side of the tube facing the window aperture area, together with web areas having a side facing the window aperture area on either side of the tube providing the heat absorption area; the adjoining webs of adjoining elongate collector bodies being movable, free of mechanical constraint or mutual attachment in relation to one another, but together presenting to the incoming solar radiation an uninterrupted area for absorption, viewed in a direction normal to the heat collector assembly. More particularly, in order for the webs of adjoining heat collector bodies to be movable in relation to one another, these webs of adjoining collector bodies are disconnected from one another but overlap. PCT/ZA201 1/000006 and corresponding national and regional phase applications by cross-reference are part of the present disclosure.

It was found that the above proposal needed further refinements for reliable slidability, bearing in mind the weight of the solar heat collector assembly, particularly when filled with heat transfer liquid, and the dimensional changes caused by thermal expansion and contraction, combined with ease of assembly in mass manufacture and providing a neat outside finish to the completed panel.

In addition, it was found advisable to provide additional protection against water ingress into the panel even under severe weather conditions, even if the sides of the panel are exposed to weather. The suspension must furthermore be capable of being manufactured from materials able to withstand the high temperatures which can occur under extreme operating conditions and minimise heat losses through the slidable suspension region.

German Gebrauchsmuster 9418188 and DE 2803821 A1 both disclose solar heat flat panel collectors including solar heat collector assemblies composed of two manifolds between which a plurality of extruded collector bodies are fitted side by side, each comprising a tube extending continuously in the extrusion direction of the profile and integrally extruded with the tube on each of the opposite sides of the tube (also known in the art as "riser tube") a web (also known as a "fin") facing the window area of the panel. The adjoining webs of adjoining collector bodies are not connected and their respective edges face each other with a gap in-between, whereas the terminal edges of the webs abut the manifolds. Also, in contrast to the disclosure of PCT/ZA2011/000006, the heat collector assembly according to G 9418 188.8 is not suspended and the manifold ends are not supported by walls of the flat panel casing in slider brackets. Instead, the heat collector assembly rests on the thermal insulation material covering the bottom wall of the casing. Any movement caused by thermal expansion or contraction of the heat collector assembly will impact on the insulation material. Inlet and outlet pipe nipples connected to the manifolds are surrounded by frustoconical sleeves of undisclosed material, where they pass through the peripheral walls of the casing. No description is given as to how this arrangement is intended to withstand and cope with the stresses and wear and tear caused by the aforesaid thermal expansions and contractions.

By way of contrast, DE 2803821 A1 discloses a solar heat collector panel, wherein a heat collector assembly, as aforesaid, is freely suspended by manifold ends thereof supported in slider brackets, which allow for thermal expansion and contraction, mounted inside the collector casing. The manifolds ends are, however, sealed off and do not pass through the casing wall. Sliding movement is provided by the manifold end passing loosely supported through an oblong aperture in the slider bracket. No sealing means are provided by the sliding mechanism, because the slider bracket is not exposed to outdoor weather conditions. Instead, a pipe nipple serving as inlet or outlet branches off at right angles to the manifold and passes through an aperture through the bottom wall of the panel casing. The aperture is surrounded by a flange collar surrounding a duroplastic elastomeric sealant filling the space between the collar and the pipe nipple. The extent to which the elastomeric sealant can absorb and withstand repeated thermal expansion and contraction cycles and its life expectancy before embrittlement, and mechanical fatigue and loss of sealant properties set in, is obviously limited.

Accordingly, neither DE G 9418188.8 nor DE 2803821 A1 can satisfy the needs set out further above.

According to the invention, the suspension of a solar heat collector assembly as set out in the generic clauses above, includes the following features: a wall region of the casing having an aperture dimensioned for the passage there through and through the wall region of an end member of a manifold of the solar heat collector assembly and for allowing linear displacement of the end member transversely to the wall region in a sliding direction, normal to the axis of the end member;

an outer slider bracket member in sliding relationship to the outside of the wall region and covering the outside of the aperture through the wall region within the limits of joint linear displacement of the outer slider bracket member and the end member of the manifold, said end member being held in the outer slider bracket member;

an inner slider bracket member in sliding relationship to the inside of the wall region and in fixed relationship to the outer slider bracket member, the end member of the manifold passing through and being supported in an aperture of the inner slider bracket member; and

guide profilings on the wall region parallel to the sliding direction;

guide formations on either or both of the outer slider bracket member and the inner slider bracket member, said guide formations matching and being in sliding engagement with guide profilings as aforesaid on the outside of the wall region.

More particularly, the inner slider bracket member has guide formations matching and being in sliding engagement with guide profilings as aforesaid.

Alternatively or preferably in addition the outer slider bracket member has guide formations matching and being in sliding engagement with guide profilings on the inside of the wall region.

The wall region having the aforesaid aperture is preferably part of a side wall of the casing of a solar heat flat panel collector.

However, in some embodiments it may be preferred that the wall region having the aforesaid aperture is part of the bottom wall of the casing of a solar heat flat panel collector. More particularly, the wall region is a region of a side wall of a panel casing for containing the solar heat collector assembly, and the axis of the end member is coaxial with or parallel to a longitudinal axis of the manifold. Alternatively, the wall region is a region of a bottom wall of a panel casing for containing the solar heat collector assembly and the axis of the end member is normal to a longitudinal axis of the manifold. The sliding direction is designed to compensate for thermal expansion and contraction parallel to the plane of the bottom wall.

The terms "inside" and "outside" relate respectively to the inside and the outside of the casing containing the solar heat collector assembly.

More particularly, the outer slider bracket member, through which passes in sealing relationship the end member for the manifold, in all its sliding positions, performs the function of an external closing plate covering the aperture for the passage therethrough of the end member of the manifold, and has guide profilings matching and sliding engagement with guide profilings on the outside of the wall region; The inner slider bracket member has guide formations matching and in sliding engagement with guide profilings on the inside of the wall region; the outer and inner slider bracket members on opposite sides of the wall region are rigidly interconnected by fasteners passing through the aperture on opposite sides, in the sliding direction of the tubular end member and for accommodating the fasteners and, at the same time, limiting the extent of the sliding movement of the slider bracket, the aperture through the wall region is extended by sliding limiting extensions.

A use according to the invention of the suspension of a solar heat collector assembly, set out above, is that it forms part of a solar heat flat panel collector, e.g. a solar water heater flat panel, either of the direct or indirect heating type and either using thermo- siphoning or pumped circulation of the heat transfer liquid.

Preferably, the solar heat flat panel collector is of the type and incorporates features in accordance with PCT/ZA201 1/000006 and/or ZA2011/00688 which, by reference thereto, are to be considered part of the present disclosure. Further or alternative or preferred features of the invention will become apparent from the following description with reference to the accompanying drawings, wherein

Fig. 1 represents a side elevation of a side wall region of a panel casing from the outside with an outer slider bracket member;

Fig. 2 represents a similar view of the side wall region alone;

Fig. 3 represents a longitudinal section along line III - III in Fig. 1 of the outer slider bracket member alone;

Fig. 4 represents a cross section of the outer slider bracket member along line IV - IV in Fig. 1 ;

Fig. 5 represents a side elevation of the inner slider bracket member;

Fig. 6 represents an end on view of the inner slider bracket member;

Fig. 7 represents a sectional view taken along line VII - VII in Fig. 1 of the slider bracket assembly;

Fig. 8 represents a diagrammatic sectional view of a different embodiment of a suspension of a solar heat collector assembly, wherein the manifold end member passes through the backing wall of a panel casing.

Fig. 9 represents a cross-sectional broken away partial view of that part of an embodiment of a solar heat collecting device according to the invention, where one of the manifold end members passes through a peripheral (side) wall of the casing without provision for sliding transversely to the peripheral wall, but in sealing relationship due to a grommet as shown in Fig. 10.

Fig. 10 represents a cross-section of an elastomer grommet providing a passage for the manifold end member in Fig. 9. Referring to Figs 1 - 7 of the drawings, there is shown an extruded aluminium alloy profile forming a side wall 201 of the casing of a solar heat flat panel collector of the type described in PCT/ZA201 1/000006 and in ZA201 1/00688. The flat wall region 202 of the side wall 201 has an aperture 203, as shown in Fig. 2, which is elongate and dimensioned for the passage there through and through the wall region 202 of a tubular end member 204, fitted to the end of a manifold 205 of a heat collector assembly. The shape and dimensions of the elongate aperture 203 are designed to allow linear displacement as shown by the arrows 206 of the end member 204 transversely to the wall region 202 in a sliding direction, normal to the axis 207 of the end member and parallel to the extrusion direction of the profile forming the side wall 201 , which side wall 201 has an outside 208 and an inside 209.

On the outside 208 the side wall 201 has guide profilings 210 and 21 1 , parallel to the sliding direction 206. On the inside 209 the side wall 201 has guide profilings 212 and 213, parallel to the sliding direction 206. It should be understood that the guide profilings 210 - 213 may have additional functions in the overall context of the panel, e.g. as described in the aforesaid earlier PCT application.

For supporting the solar heat collector assembly by way of the end member 204, the suspension mechanism uses a slider bracket composed of an outer slider bracket member 214, performing the function of an external closing plate and an inner slider bracket member 217. The outer slider bracket member 214 is in sliding engagement with the outside 208 of wall region 202 and has guide formations 215, 216, matching and in sliding engagement with the guide profilings 210, 21 1. The inner slider bracket member 217 has guide formations 218, 219, matching and in sliding engagement with the guide profilings 212, 213.

The outer and inner slider bracket members 214, 2 7 on opposite sides of the wall region 202 are rigidly interconnected by fasteners 220, e.g. screws passing through the elongate aperture 203 on opposite sides of the tubular end member 204. For accommodating the fasteners and at the same time limiting the extent of the sliding movement of the slider bracket 214, 217, the elongation of the aperture 203 is extended by tapering extensions 221 . The distance between the slider bracket members 1 14, 1 17 matches the thickness of the wall region 202 with just sufficient tolerance to provide for easy sliding. This distance (see the gap 262 in Fig 7) is determined by hollow cylindrical spacer studs 260, through each of which one of the fasteners 220 passes. The spacer studs 260 may preferably be integral with either of the slider bracket members, in this example with the outer slider bracket member 214 and preferably each fit into a matching socket 263 of the other slider bracket member, in this case the inner slider bracket member 217.

The slider bracket members 214, 217 are preferably made, e.g. by injection moulding, of a plastics having a low coefficient of friction when sliding on the smooth surface of the side wall region, e.g. made of aluminium, and being able to withstand high temperatures, preferably a thermoplastic resin composition, UV-stabilised polycarbonate being particularly preferred.

The aforesaid tapering extensions 221 of the aperture 203 terminate in a curvature 270, matching the exterior curvature of the hollow cylindrical spacer studs 260 and serve as stop formations which, by engagement with the respective spacer stud 260, limit the extent of sliding movement 206 of the slicer bracket, the other slider bracket member 214, as shown in Fig. 1 , stopping just short of the edge 271 of a corner piece 272 of the frame of the flat panel solar heat collector panel.

Because the axis 207 of the end member 204 coincides with the axis of the manifold 205 (shown fully only in Fig. 8), the solar absorption area of the solar heat collector assembly is preferably extended by a web or fin 273, shown in broken lines in fig. 2, connected to and preferably integral with the manifold 205, of which a portion is diagrammatically indicated by a broken line 205 as shown in Figs. 3 and 4.

The preferably internally screw-threaded end member 204 which is either integral with the manifold 205 or is fitted thereto as a coaxial linear extension of the manifold 205, is accommodated with a tight fit in a matching aperture 222 of the inner slider bracket member 217 and from there passes first through the elongate aperture 203 of the wall region and then passes in sealing relationship through a further aperture 223 of the outer slider bracket member 214. The sealing relationship may be provided by a sealing substance, but is preferably provided by an elastomeric grommet 231. For fitting the grommet 231 to the outer slider bracket 214, the latter is recessed at 274 to form an inwardly directed annular flange 275 matching an external annular groove of the grommet surrounding the outer periphery of the end member 204.

The end member 204 is preferably threaded, preferably by an internal thread 225 for connecting whatever fittings are needed, e.g. inlet or outlet ducting, optionally fittings for holding a sacrificial anode for corrosion protection (as more fully described in the aforesaid PCT specification) or alternatively for blocking off that manifold end with a threaded plug.

In order to cover or partly cover any gap between the manifold 205 and the adjoining parallel panel end wall 226, fitted to the side wall 201 by a corner member 227, the manifold 205 may carry an absorption web or fin 228 forming an integrally extruded part of the extruded manifold profile.

As in the case of PCT/ZA201 1/000006 and ZA201 1/00688, the solar heat collector assembly is preferably formed by two aluminium alloy manifolds at opposite ends between which a plurality of extruded aluminium alloy collector bodies are fitted, the collector bodies each consisting of a tubular passage connected to the manifolds and flanked on opposite sides by absorption webs or fins slightly overlapping with the webs or fins of the adjoining collector body, to form a continuous absorption surface. The overlapping fins are not interconnected.

The above described slider bracket arrangement supporting an end member 204 at one end of one of the manifolds 205 is preferably repeated at the opposite end of the manifold 205 in relation to the side wall on the opposite side of the panel.

Normally, in analogy to embodiments described in PCT/ZA201 1/000006, only one of the two manifolds is thus movably suspended. As shown in Figs. 9 and 10, the second manifold at the opposite end of the solar heat collector assembly will usually be suspended from the side walls 201 in substantially fixed interrelationship by means of end members, e.g. identical to the end members 204, passing through matching apertures 230 through the side wall 201 in sealing relationship provided by elastomeric grommets 231 not shown in Fig. 9. Such an arrangement provides limited flexibility due to the elasticity of the grommets and also a degree of slidability in the axial directions, but no slidability transversely to the plane of the side wall.

In a preferred embodiment of the invention, the side 236 of the inner slider bracket member 217 facing the elongate aperture 203 is slightly concave at 239 between two narrow flat surface strips 232 in sliding contact with flat areas of the side wall 201 , parallel to the sliding direction 206 adjoining the elongate aperture 203.

Also, deep depressions 233 are provided near each of the four corner regions of the inner slider bracket member 217. These depressions not only save material, but also facilitate rapid and uniform solidification of the moulding during manufacture by injection moulding.

The features described with reference to Figs 1 to 7, when combined with features of PCT/ZA201 1/000006 or ZA201 1/00688, serve to minimise thermal stresses in solar heat collecting flat panels.

For better understanding a more complete description of Fig. 9, illustrating the application of the present invention, an embodiment of a flat panel according to PCT/ZA201 1/000006 is given in what follows:-

In the embodiment of Fig. 9, the solar heat collecting device, shown here only in part, comprises four side wall members 201 (of which only one is shown, i.e. in section), preferably all having the same extruded profile, preferably of aluminium or aluminium alloy, connected by corner pieces (not shown here) to form the four sides of a panel casing 14 and defining at its top side the inner edge 9 of a flange 10 of the window aperture area 1 1 through which solar radiation is to enter the device. The window aperture area is closed by a highly light-pervious cover panel 12, fitted onto the flange 10 in sealing relationship by virtue of a sealant, not shown. In order to protect the sealant against UV-degradation and at the same time to protect the edge of the cover panel 12 against fracture, this edge region preferably carries a UV-im pervious protective layer 13, e.g. of plastics or ceramics. The bottom of the panel casing 14 is formed by a backing panel 15 of a suitable sheet material fitted in sealing relationship to the side wall members 201 between a flange 16 and a counter-flange 17 forming part of the side wall member 201 . The backing panel may, for example, be made of sheet metal, e.g. aluminium, fibre cement, wood fibre board or preferably a plastics-coated fibre board, e.g. melamine plastics-coated, e.g. the product known in the trade as Formica.

In a preferred embodiment of the side wall member 201 , the major portion of its extruded profile comprises a preferably flat side wall portion 18 into which is/are punched or otherwise cut a perforation or perforations 21 where needed, to allow the passage of a manifold end member 204 or other extension of a manifold 20. Such manifolds, connected at opposite ends to a plurality of the elongate heat collector bodies together constitute a heat collector assembly. Above the level of the perforation(s) 21 the side wall portion 18 forms a rebate 22 for accommodating a matching bead 23 of a corner piece (not shown), followed in upward direction by a channel-shaped top limb 25, terminating in a downwardly-directed leg 26 parallel to the side wall portion 18 from which projects the flange 10.

Below the level of the perforation(s) 21 , the side wall portion 18 forms a T-shaped rebate 125 for accommodating holding formations (not shown) of panel mounting means (not shown). The rebate 125 is, in turn, followed in downward direction by a second rebate 22 which, like the above-described rebate 22 serves to accommodate a second matching bead 23 of the corner piece. This is, in turn, followed in downward direction by a bottom limb 27, similar to the above-described top limb 25, except that the leg 26 may optionally be extended by a continuous wall portion 28 which continues upwards to connect up with the T-shaped rebate 125 and becomes the rear wall thereof. In this manner a closed tubular cavity 29 is formed between the bottom limb 27 and the lower wall of the rebate 125. The tubular cavity 29 improves the torsional rigidity of the profile. The aforesaid flanges 16 and 17 holding the back panel 15, project from the wall portion 28. It will be appreciated that dimensional variations of the side wall profile are within the scope of the invention. For example, the size of the gap between flanges 16 and 17 will depend on the thickness of the backing panel 15 and optional support braces. The height of the cavity 29 can be varied depending on the thickness of the insulations 35. 36 Represents the level by which the manifold is suspended above the insulation 35. 37 Represents wall insulation. 30 Shows the inner periphery of the manifold 20 and 32 (33) represents internal threading of the manifold end member for optional connecting purposes or for a plug 251 as in Fig. 8.

Referring now to Fig. 10, an injection-moulded heat-resistant elastomer grommet 231 has an inner periphery 52 tightly fitting around the outer periphery of the manifold end member 204, where it passes through the perforation 21 of the side wall portion 18 of the side wall member 201. It also has an outer annular groove 53 for accommodating the edge defining the perforation 21 of the side wall portion 18 with a snap-fit. For weather- proofing a sealant may be applied to the surface of the groove 53, e.g. that formed by the chamfered outer annular flange of grommet 231. The elastomer may e.g. be an isoprene polymer. A suitable elastomer is commercially available under the trade name Forprene.

Referring now to Fig. 8, parts which are the same or functionally the same as in Figs 1 to 7 are indicated by the same reference numbers as before.

In the aforegoing description, with reference to Figures 1 to 7, it was assumed that the solar heat collector assembly would be suspended in the panel casing from the side walls fitted with slider brackets, more particularly where the inlets and outlets for heat carrier medium would pass coaxially with their manifolds 205 through the side walls 201. However, if, in the alternative, the inlets and/or outlets are intended to pass through the back wall, i.e. the underside of the panel, it is also possible to provide the slidable suspension mechanism as part of the backing wall, i.e. in a plane normal to the plane of the side wall and using tubular end members 234 of the respective manifold 205 orientated at right angles to the manifold axis and passing through the back wall 237, i.e. the underside 235. In order to achieve this, a piece of profiled section (not shown) incorporating the relevant features of the flat wall region 202 and adjoining relevant features may be fitted to the backing wall 237 itself at right angles to the side wall, or as only diagrammatically indicated in Fig. 8, may be otherwise fitted to the backing wall 237 or may be partly or wholly integrated as a flange extension 238 at right angles to the side wall 201 , in order to provide guide profilings 242 and 243 fitting and matching the guide formations 218, 219 of the inner slider bracket member 217. The end member 234 is in the example of Fig. 8, welded or hard soldered (brazed) to the manifold 205 by having its end 244 inserted into a matching hole 245 through a plane wall region 246. The welding or hard soldering is performed with automatic temperature control to produce the desired flow of a welding or soldering substance compatible with the aluminium alloy of the extruded manifold 205 and the end member 217, so as to completely fill the interface between the hole 245 and the end 244 and form a perfect inner bead 247 and outer bead 247' free of hair cracks.

In order to prevent downward slipping of the end member 234 through the aperture 222 of the inner slider bracket member 217, the latter may have an external shoulder or flange 248 or other arresting means.

Also in Fig. 8 there is shown a hole 250 where an end of the riser tube portion of one of a plurality of absorber bodies described in PCT/ZA201 1/000006 and ZA 201 1/00688 is to be fitted to the manifold, essentially in a manner analogous to the fitting by welding or brazing described above for the tubular end member, in order to complete the solar heat collector assembly.

In this example, the end of the manifold is closed by a screwed-in plug 251 . It will be understood that this plug could also be used as a holder for a sacrificial anode projecting into the manifold.

The manifold 205, together with the remainder of the entire solar heat collector assembly is supported on the tubular end member 234 freely and movably suspended above and clear of the upper surface 252 of a heat resistant layer of insulation 253, and underneath the solar radiation admitting cover panel 254, e.g. having the characteristics set out in PCT/ZA201 1/000006 and ZA201 1/00688.

The linear sliding direction dictated by the mounting of the slider bracket 214, 217 and its guiding formations may be at an angle to the projection of the longitudinal axis 255 of the riser tubes, such angle being calculated in accordance with the longitudinal and lateral dimensions of the solar heat collecting assembly in order to compensate for thermal expansion and contraction in both dimensions. What is described with reference to Fig. 8, in combination with the features forming the subject of PCT7ZA2011/000006 and ZA2011/00688, can likewise minimise thermal stresses.

To the extent that this may be relevant in the context of thermal expansion and contraction, e.g., concerning the overlap between the webs (fins) of adjoining heat collector bodies of the heat collector assemblies, measurements given are generally measured in the cold condition, i.e. at ambient room temperature of 20°C.