A DUCTWORK ASSEMBLY, SUPPORT AND SUSPENSION SYSTEM

Abstract: A ductwork assembly comprising a pair of ducts (10, 11) and a supporting ladder structure (12) between them, the ladder structure (12) being suspended from above by cables. Each duct (10, 11) is supported from the adjacent side of the ladder structure (12) by half moon brackets by which it is cradled. Each half moon bracket is mounted at the end of an outwards extension of a rung of the ladder structure (12). The latter supports various services such as cables, cable trays, cable trunking, lighting systems, smoke detectors and/or security systems.

Description: A DUCTWORK ASSEMBLY. SUPPORT ft SUSPENSION SYSTEM This invention relates to a ductwork assembly and a support and suspension system for circular ducts. Ventilation ducts, tubes, trunking and other piping are often concealed in buildings. However there are occasions when they are exposed. In such circumstances, it is desirable to take into account the external appearance of the ducts etc. and of their support and suspension systems. US-A-5094273 discloses ventilation ducting which is suspended from an overhead cable or other suspensions means. This ducting is designed for use in restricted environments such as mine shafts and tunnels. Specifically the ducting is designed so that the space it occupies is reduced from that of conventional circular cross-sectional tubing. The disclosed ducting has two ducts, each of tubular configuration and comprising an end section at each end of an intermediate section which extends for a major part of the overall length of the tubing. The end sections are formed as tubular elements. The intermediate sections of each portion of the tubing have a common wall throughout their length. The common wall is defined by a web of material which extends between the upper and lower surfaces of the tubing. An object of the present invention is to provide a ductwork support assembly and a support and suspension system for supporting circular ducts which is strong, aesthetically pleasing and easy to assemble. According to one aspect of this invention there is provided a ductwork support system as claimed in claim 1. According to another aspect of this invention there is provided a ductwork assembly as claimed in claim 2. Preferred features of the ductwork support system or assembly are claimed in the sub-claims. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 is a perspective view from below of two ventilation ducts of a ventilation ductwork system suspended from a roof of an enclosure by a ductwork support and suspension system; Figure 2 is a schematic in plan of part of the ventilation ductwork system incorporating the ventilation ducts and the ductwork support and suspension system shown in Figure 1; Figure 3 is a schematic side elevation of a part of the ventilation ductwork system which is identified in Figure 2 as detail A; Figure 4 is a plan view of Figure 3; Figure 5 is a view similar to Figure 3 of detail B in Figure 2; Figure 6 is a plan view of Figure 5; Figure 7 is a view on arrow C in Figure 2; Figure 8 is a view on the line VIII-VIII in Figure 2; Figure 9 is a view to a larger scale of detail D in Figure 3; Figure 10 is a view on the line X - X in Figure 9; Figure 11 is a view on the line XI - XI in Figure 9; Figure 12 is a sectioned view of detail H in Figure 8 to a larger scale; and Figure 13 is a side view on arrow G in Figure 2 of a fragment of one of the ventilation ducts. Figures 1 to 6 show a ventilation ductwork system which comprises two long ventilation ducts 10 and 11 which are supported side by side from a roof by a suspension system. The ducts 10 and 11 comprise tubular lengths joined together end to end. Each tubular length is formed from an 18 SWG rigidised aluminium sheet. Each such a sheet is cut to length from stock in coil form, rolled into the form of a tube and joined at its ends to form a seam which completes the tubular length. The tubular lengths are joined together end to end to complete each duct 10,11 by a jointing system which forms the subject of my co-pending International Patent Application no. PCT/GB96/ which designates the priority of my British Patent Applications No. 9506670.0 filed 31 March 1995 and No. 9604939.0 filed 08 March 1996. Specifically each juxtaposed pair of the tubular lengths are joined together end to end by an internal ring which is fitted into and secured within each of the tubular lengths it joins. The ring is formed with an annular groove which runs circumferential between the pair of tubular lengths. The sheet material of the tubular lengths is turned down at the ends of those lengths that are joined by the ring, the turned down portions extending into the hollow formed by the groove and a bend radius being formed at the outer end of each turned down portion. The suspension system comprises an elongate ladder structure 12 which extends between the ducts 10 and 11, which are supported from it, and which, in turn, is suspended from the roof by groups of suspension cables at spaced locations 13 (see Figure 2) along the length of the ladder structure 12. The ducts 10 and 11 lead to splitter boxes 14 which are provided at certain locations in the ductwork system. The detailed construction of a splitter box 14 is described and illustrated in my aforementioned co-pending International Patent Application no. PCT/GB/96 Basically it is hollow and each duct 10, 11 communicates with its interior which also communicates through one of its side walls with two similar ducts 15 and 16 which depend from the splitter box 14 to extractor plant below. In operation of the ventilation system, air is drawn into each duct 10,11 through various grilles 17 which are provided in its upper surface by operation of the extractor plant which draws that air from the ducts 10 and 11 and through the splitter box 14 and the depending ducts 15 and 16, as is shown by the arrows 18 in Figure 2. Figure 3 and 4 and Figures 8 to 11 show the arrangement of the groups of suspension cables at each spaced location 13 which is remote from a splitter box 14. There are two support brackets 21 and 22 fixed to the roof at each location 13. They are spaced apart by a distance which is greater than the width of the ladder structure 12 which passes symmetrically between them and below them. Three cables 23 to 25, 26 to 28 depend from each support bracket 21,22. Two of those cables 23 and 25, 26 and 28 depend to the nearer side member 31,32 of the ladder structure 12 to which they are fixed (see Figure 12) at a location (see Figures 3 and 4) which is spaced along that side member 31,32 from the point on that side member 31,32 that is nearest to the respective support bracket 21,22 so that an acute angle is included between the cable 23,25,26,28 and the ladder side member 31,32 to which it is fixed. Each of those cables 23,25,26 and 28 is connected to the respective support bracket 21,22 by a simple pin joint 33,34 as is shown in Figures 9 and 11. The third cable 24,27 depends to the further side member 31,32 of the ladder structure 12 (see Figure 8) to which it is fixed (see Figure 12) at the point on that further side member 31,32 that is nearest to the respective support bracket 21,22. Each third cable 24,27 is fixed to the respective support bracket 21,22 by a toggle linkage 35 (see Figures 9 and 10) which allows pivotal movement of the cable 24,27 relative to the support bracket 21,22 about two mutually perpendicular axes. This suspension arrangement leads to the ladder structure 12 being supported in a stable manner and being braced against lateral displacement, swinging about the cables. Figures 5,6 and 7 show that the adjacent one 37,38,41,42 of the groups of cables nearest to the splitter box 14 is fixed to the top of the splitter box 14 rather than to the ladder structure 12. The anchorage for each of those cables 37,38,41 and 42 on the top of the splitter box 14 is provided by a respective upstanding channel section strip 43,44 of aluminium which is fitted to the top of the splitter box 14. Each of the suspension cables is provided with means 36 (such as a turnbuckle) for adjusting its length. Rods may be used instead of cables. Figures 1 and 8 show that the side members 31 and 32 of the ladder structure 12 are channel section members which are arranged with their flanges extending outwardly towards the nearer one of the ducts 10 and 11. Figure 8 shows that a deep channel section tray 40 depends from the two side members 31 and 32 of the ladder structure 12. At certain locations 45 (see Figure 2) the tray 40 supports uplighter equipment 46 (see Figure 8) and at other locations 47 (see Figure 2) it supports downlighter equipment 48 (see Figure 8). The tray 40 also serves as a support for cables, smoke detection system equipment, security system equipment and other such service equipment which would be concealed from view below. Each rung 49 of the ladder structure 12 is tubular (see Figure 12) and has a tubular projecting portion 51,52 which projects outwardly beyond each side member 31,32 (see Figure 8). Each projecting portion 51,52 carries a respective support cradle 53,54 at its outer end (see Figures 1 and 8). Each support cradle 53,54 comprises a crescent shaped piece which is arranged with its convex side connected to the respective projecting portion 51,52. The two longitudinally extending ducts 10 and 11 are supported one in each of the crescent shaped pieces of the support cradles 53 and 54 by being cradled in the crescent shaped pieces. Each tubular rung 49 has a tubular insert 55 positioned in each of its ends (see Figure 12). Each insert 55 has a threaded hole 56. The adjacent side member 31,32 is welded at 57 to an end of the rung 49 and to the insert 55. A hole in the intervening side member 31,32 provides communication between the bore of each tubular projecting portion 51,52 and the respective insert 55. A hole 58, which is drilled through the crescent shaped piece of the respective support cradle 53,54, receives the respective tubular projecting portion 51,52 which is attached to the rung 49 by a set- screw 59 which passes through the respective tubular projecting portion 51,52 and is screwed into the threaded hole 56 in the respective insert 55. The axes of the set screws 59 lie in the medial plane of the ladder structure 12 and that plane is substantially coincident with the plane that includes the axes of the ducts 10-and 11. Figure 13 shows an expansion joint 61 which is provided at certain locations along the ducts 10 and 11 and which is required when more than fifty meters of pipe is provided. The use of the central ladder structure 12 has the advantage that the weight of the arrangement can be kept relatively low. The ladder is sufficiently rigid to prevent the rungs and their projecting portions, which effectively comprise a single rod, moving out of alignment with each other, thereby reducing the likelihood of distortion or bending of ducts that are placed in the support structure, whilst at the same time minimising the overall weight. The ductwork support and suspension system in which the present invention is embodied is strong and relatively easy to assemble. Since the ladder structure and the projecting portions of its rungs are positioned between the ducts, they are mainly concealed, so that when viewed from below the overall effect of the system is aesthetically pleasing. The use of cradle supports further improves the aesthetic appeal of the system as the outward appearance of the ducts is not detrimentally affected by their presence. Ducts with relatively large diameters, for example three meters, may be used in the ductwork system in which the present invention is embodied. Such ducts provide a free space at the top enabling air flow dampers to be installed hidden from view of a casual observer below.

Claims: "AIMS - 1. A ductwork support system for supporting two adjacent ducts from a surface, characterised in that the support system comprises a framework having longitudinally extending sides, wherein the framework carries at least one pair of supports, the supports of each such a pair being arranged one on either side of the opposing sides of the framework and each being operfible to receive and to support a respective one of the ducts so that when the ducts are supported by the supports, the framework extends between the two ducts and spaces them apart. 2. A ductwork support system according to claim 1, including elongate tension members by which the framework is to be suspended from the surface so that it is substantially horizontal. 3. A ductwork support system according to claim 2, wherein the tension members are arranged in groups of at least three, such groups being arranged in pairs, one group of each pair being on the opposite side of the framework from the other group of that pair and one tension member of each group being connected to the opposite side of the framework while the other tension members of that group are connected to the nearer side of the framework 4. A ductwork support system according to claim 3, wherein the tension members are cables or rods. 5. A ductwork assembly comprising a pair of elongate ducts and means whereby the ductwork assembly is to be suspended by cables so that it is substantially horizontal, wherein each duct comprises tubular lengths of sheet material joined end to end, characterised in that said means comprise an elongate supporting framework having a pair of longitudinally extending sides, each duct being supported by a respective one of the pair of longitudinally extending sides of the framework so that the framework extends between the two ducts, spaces them apart and has its medial plane which passes through the sides substantially coincident with the plane that includes the axes of the ducts. 6. A ductwork assembly according to claim 6, wherein the sheet material of each tubular length is light gauge and has been cut from coiled strip material and joined at its ends to form a seam which runs the length of the resultant tubular length. 7. A ductwork system or assembly according to any one of claims 1 to 6, wherein the framework is a ladder structure. 8. A ductwork system or assembly according to any one of claims 1 to 7, wherein each duct is supported from the framework by half moon brackets by which it is cradled. 9. A ductwork system or assembly according to any one of claims 1 to 8, wherein the framework is operable to receive and support cables, cable trays, cable trunking, support lighting systems, smoke detection systems, and/or security systems. 10. A ductwork system or assembly acccording to claim 8, or claim 9 when appended to claim 8, wherein the framework is a ladder structure and the two brackets of each pair are connected so that there is a half moon bracket at either end of a rod which forms a -rung of the ladder structure. 11. A ductwork system or assembly according to any one of claims 1 to 10, wherein each duct is circular and comprises tubular lengths of sheet material which are joined together end to end and which each have an externally visible surface and an inner surface, each juxtaposed pair of tubular lengths being joined together by a ring which is spigotted into and secured to each of them, each ring being formed with an annular groove which runs between the juxtaposed ends of the respective pair of tubular lengths, the sheet material of the tubular lengths being turned down at said ends, the turned down portions extending inwardly, away from said externally visible surfaces and into the hollow formed by said groove, a bend radius being formed where each turned down portion meets it respective externally visible surface. 12. A ductwork system or assembly according to any one of claims 1 to 11, wherein the ducts lead to splitter boxes which are provided at certain locations in the ductwork system. 13. A ductwork system or assembly according to claim 12, wherein each splitter box is hollow and each duct communicates with its interior which also communicates through one of its side walls with two similar ducts which depend from the splitter box for connection to extractor plant below. 14. A ductwork system or assembly according to any one of claims 2 to 13, wherein grilles are provided in each of the ducts. 15. A ductwork system or assembly according to either of claims 12 and 13 when appended to claim 4, or claim 14 when appended to claims 4 and 12, wherein the adjacent one of the groups of cables nearest to each splitter box is fixed to the top of that splitter box rather than to the framework.

Inventors: FINESTONE JAMES, HACLIN GRAHAM JOHN, FINESTONE, JAMES, HACLIN, GRAHAM, JOHN
Applicants: FINESTONE JAMES, HACLIN GRAHAM JOHN, FINESTONE, JAMES, HACLIN, GRAHAM, JOHN
Application year: 1996
Main classification: F16L3
IPC codes: F16L3, F24F13