AU701799B2 - Solar heater casing - Google Patents

Description

This invention relates to a casing for a solar heater of the type which has a pair of convection pipes extending from one end to the other, and which has a heating plate extending between the pipes, the heating plate being in close contact with tubes which extend between the pipes and are in fluid flow communication therewith.

Solar heating casings are presently produced by simple fabrication means, with welded or riveted joints between folded sheet metal panels, and are scarcely adequate for the weathering which occurs. The main object of this invention is to provide an improved casing which has a reduced number of parts, is more rugged than those presently produced, and which is easily and quickly assembled, is better able to hold its shape under adverse conditions which may be encountered, and retains an improved visual appearance.

In one embodiment of the invention there are two end extrusions each of constant cross-sectional shape, two side extrusions each also of constant 15 cross-sectional shape, four corner blocks of L-shape, two right hand and two left hand, each end block having one of its flanges with walls defining an aperture through which a pipe end passes, and grommet means which engage the aperture walls and also engage the outer surface of the pipe ends.

By utilising constant cross-sectional shape sections, even though the end sections and side sections may be different, the ends and sides can be of extruded metal and therefore of relatively low cost but high resistivity of weathering if aluminium is used, and by having spigot and socket joints between the side and end extrusions and the projecting ends of the corner blocks, a very rugged and substantial fabrication may be achieved. By utilising rubber grommets between the corner block flanges and the pipes, the metal expansion of the pipes upon heating can be readily accommodated.

Two embodiments of the invention is described hereunder in some detail with reference to and are illustrated in the accompanying drawings in which: Fig 1 is an elevational section through a solar heater casing; Fig 2 is a top view of Fig 1, and showing the section plane 1-1 of Fig 1; Fig 3 is a perspective "exploded" sketch showing the interconnection between a side extrusion and an end block; Fig 4 is a section through an extrusion according to a second embodiment; Fig 5 is a 'fragmentary' perspective view showing a join between a corner block and an end extrusion; and Fig 6 illustrates the securing of the glass in the second embodiment.

The casing 10 comprises two extrusions 11 each of which is of constant cross-sectional shape throughout its length, the end extrusions 11 extending along the top and bottom of case 10. Two side extrusions 12 are also of constant cross-sectional shape throughout their length, although that shape :i differs from the extrusion shapes 11 in that the side extrusions do not have any projecting flanges, and four corner blocks 13 which join the end extrusions to the side extrusions.

Fig 3 more clearly illustrates the cross-sectional shape of a top (or bottom) extrusion 11, each side extrusion 11 having an outstanding flange 14 e* along its lower edge for mounting to a roof, and that is surmounted by a pair of flanges defining a narrow U-shaped groove. The lower of the two flanges "and 15b projects inwardly, then slopes downwardly to ease assembly, the upper also projecting inwardly, but the upper flange 15a terminating in a return edge 16. The flange 15a merges into an upstanding web 17, and the upstanding web 17, which separates the flange 14 from the flanges 15a and 15b, terminates at its upper edge in an upper inturned horizontal glass retaining flange 18 (as drawn), and that is spaced above a glass support flange 19 which has a depending L-shaped stiffener rib 20 depending from near its inner edge. Thus the two upper spaced flanges 18 and 19 define between them a glass support channel 22, and this supports the edge of the glass panel 23 (Fig Rib 21 extends along the base of channel 22, and imparts any stress applied to glass edge to its central plane, the neutral axis of the glass. The channel width is less in the corner blocks than in the extruded rails, and this diminishes stress applied to the glass. The flanges 15a and 15b defining the U-slots support a lower metal sheet 24 which in turn supports an insulating pad 25 which underlies a heating plate 26, the heating plate 26 being contiguous with the tubes 27 the ends of which penetrate bell-mouthed openings in the convection pipes 28. Sheet 24 is chamfered at its corners 29 to provide ventilation, and reduce fogging of the glass panel 23.

Each corner block 13 has two webs 30 at right angles to each other, one the webs 30 having an oval shaped trough-like depression 31 which defines :an opening 32 through which are end of a pipe 28 passes, thereby supporting the pipe-end as well as the heating plate centrally between the flanges 15 and 15 19. A resilient grommet 32a allows some lateral movement of the header tube which may occur due to thermal expansion, which is double in copper the expansion in glass, and this is supplemented by the oval shape of depression a a.

31 and opening 32. A short channel-shaped extension 33 extends outwardly beyond the ends of the flanges 30 of corner block 13. These flanges 33 enter the grooves defined by the inturned rib 20 and flange 19, the groove between S the return edge 16 and the upper of the two spaced flanges 15a, and also the oomoo space between the upturned edge 16 and the upstanding web 17, this being best seen in Figs 1 and 3. The corner blocks 13 also have flanges designated 18a, 19a, and a lower flange 34, the inner edge of the lower flange 34 being captive in the groove between return edge 16 and upper flange 15 of a side extrusion 11. The flange 34 is unitary with a lower half flange 35, so that when the channel shaped extension 33 enters the end of an extrusion 11, the outer surfaces of the corner block 13 and extrusion 11 are coplanar, (or continuous).

Upper flange 36 of extrusion 33 is similarly captive between flange 19 and Lshaped rib 20 (Fig 1).

The inter engagement of surfaces of the channel shaped extension 33 with the extruded side rails and end rails is over a relatively large area so that a considerable amount of friction is imparted. These extensions may be retained by simple fastening means or by adhesive, and the resultant product will resist twisting, buckling and deflection under wind or other anticipated load. The flanges 14 are utilised for securing the assembly to the roof portion of a building.

Other relevant features include chamfered edges 38 at the mouths of the glass support channels, and these facilitate assembly.

rain drip edge is provided by an outstanding rib 39 extending along S-the end rails 12 (Fig 1).

The second embodiment of Figs 4, 5 and 6 illustrate a slight variation of 15 a first embodiment. In general the features are somewhat similar and similar components bear similar designation numerals.

However, one of the features of the second embodiment is simplifying the positioning of the glass panel 23, and Fig 4 illustrates how a polymeric pad 41 is positioned on the glass support flange 19, and the glass retaining flange 18 is slightly outboard of the edge of the glass panel 23 so that the panel can be dropped into place, and thereby can be replaced without need to break down the components of the heater casing 10. Glass panel 23 is laid on the support pad 41, and the wedging strip 42 is used to retain the glass panel on the pad. Wedging strip 42 is of constant cross-sectional shape and comprises a rib 43 which is central or almost central, the rib 43 having adjacent to it a trough 44 and that trough accommodates a downturn rib 45 at the edge of the retaining flange 18. On each side of the rib 43 of the wedging strip 42, the material reduces in thickness towards its edges 46 and 47. The arrangement therefore is such that the deformable strip 42, which although not being correctly described as elastic, nevertheless will have recovery properties, can be positioned with its edge 47 within the groove surmounted by the retaining flange 18, and the bead 45 will be accommodated in the trough 44. In being deformable, the wedging strip 42 can be readily withdrawn. It will however cooperate with the pad 41 to form a substantially waterproof seal.

The invention may further include a heat shield flange 50 which slopes downwardly from flange 19 and assists in reduction of any tendency for water to freeze in the upper convection pipe 28.

The above embodiment will indicate that the invention is essentially quite simple, but nevertheless provides an improvement over prior art casings, which more than justifies any unexpected increase in expense.

6 a. a The Claims defining the invention are as follows: 1. A solar heater casing for a solar water heater having a pair of convection pipes joined by a plurality of tubes, and a glass panel, including two end extrusions, two side extrusions, and four corner blocks each having two upstanding webs at right angles to one another and each web being flanked by a lower flange and an upper flange, one web of each said corner block having an aperture therethrough through which a pipe end of said convention pipe extends upon assembly of said casing.

2. A solar heater casing according to claim 1, wherein the terminal ends of said webs and their lower and upper flanges define a channel shape, and each of said extrusions also includes a web flanked by a lower and upper flange which are spaced sufficiently that a said terminal end of a said corner block is slidably 0 15 insertable within an end of a said extrusion to be contiguous with surfaces of the web and flanges thereof.

3. A solar heater casing according to claim 2 wherein at least one of said flanges of each said extrusion terminates along its edge in a stiffening rib which retains a said flange of a corner block upon assembly against lateral displacement, thereby constituting a spigot and socket joint between a said corner block and extrusion end.

o*ooa 'a a 4. A solar heater casing according to claim 2 or 3 wherein said upper flange of each said side and end extrusion is a glass support flange, and is surmounted by a glass retaining flange which, in use, provides means for retaining an edge of a glass panel to said glass support flange.

A solar heater casing according to any one of claims 2 to 4 wherein said lower flange of each said side and end extrusion comprises two closely spaced flanges defining between them a narrow groove which, upon assembly of a water heater, can retain edges of a base panel.

Claims (6)

1. 6. A solar heater casing according to claim 4 wherein each said corner block has a pair of spaced flanges extending only part way along the upper edge of respective webs, one being a glass support flange, and the other being a glass retaining flange, said spaced flanges functioning as continuations respectively of the glass support and glass retaining flanges of said extrusions.
2. 7. A solar heater casing according to claim 4 or claim 6 wherein said glass support flange is wider than said glass retaining flange, and further comprising a wedging strip which, upon assembly of a solar heater, applies downward pressure on a glass panel and bears upwardly against said glass retaining flange.
3. 8. A solar heating casing according to claim 7 wherein said wedging strip includes a deformable material with shape recovery properties, and has a constant cross-sectional shape which includes a concave base, a central upstanding rib, 15 and a pair of flanges which reduce in thickness towards side edges. S 9. A solar heater casing according to claim 8 wherein said glass retaining flange includes a depending bead along its peripheral edge, and the shape of an upper surface of a said wedging strip includes a trough alongside said rib which 20 accommodates said bead when said strip bears upwardly against a said glass retaining flange. ooooo*
4. 10. A solar heater casing according to any preceding claim further comprising a heat shield flange extending inwardly into said casing from an inner edge of said glass support flange.
5. 11. A solar heater casing substantially as hereinbefore described with reference to and as illustrated in Figs 1, 2 and 3. 9
6. 12. A solar heating casing substantially as hereinbefore described with reference to and as illustrated in Figs 4, 5 and 6. DATE: PHILLIPS ORMONDE FITZPATRICK Attorney for BEASLEY INDUSTRIES PTY LTD 0* 4 4* 4 4 4 4 C C CO 4 C I r 'I /1 ABSTRACT A solar heater casing (10) has a pair of side extrusions (11) and a pair of end extrusions and L-shaped corner blocks each corner block (13) having flanges (33) which firmly engage surfaces at the ends of the extrusions (11, 12) to retain the casing in a rectangular shape, the corner blocks (13) having openings (32) through which ends of convection pipes (28) extend, the opening (32) shapes and sizes accommodating thermal expansion. f