GB2227806A

GB2227806A - Embossed ducting

Info

Publication number: GB2227806A
Application number: GB8902336A
Authority: GB
Inventors: Alan Bell
Original assignee: STEELPRESS
Current assignee: STEELPRESS
Priority date: 1989-02-02
Filing date: 1989-02-02
Publication date: 1990-08-08
Also published as: GB8902336D0

Abstract

Fluid ducting, especially in the form of a ventilating air conduit or a roof cowl, is formed from metal sheeting eg commercial grade steel or aluminium to provide the desired cross-sectional form of the ducting. For a closed conduit, overlapping portions (2, 3) can be provided to facilitate the metal sheet joints. The metal sheet of the ducting is provided with an array of structural embossments (E) either in the form of separate deformations (11, 12 Fig 5) or a series of continuous corrugations (13 Fig 8) to strengthen the ducting. This will enable relatively thinner sheeting to be used resulting in cost saving. <IMAGE>

Description

"FLUID DUCTING" DESCRIPTION: The present invention relates to fluid ducting especially but not exclusively for use in buildings. The invention is particularly concerned with ventilation ducting.

Fluid ducting such as ventilation ducts are constructed by connecting together metal sheeting, to form a closed conduit and to provide the necessary structural strength in the conduit it has been necessary for the sheeting of the ducting to have a certain minimum thickness. However in many cases this has resulted in the ducting having the disadvantage of being undesirably heavy. Further the greater metal usage resulting from the use of thicker sheeting has She disadvantage of increasing the cost of the ducting.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to the present invention fluid ducting comprises a conduit formed from metal sheet material which is structurally embossed so as to strengthen the material.

Preferably the structurally embossed sheet material has strength properties at least five per cent greater than a corresponding nonembossed plain sheet of a thickness equivalent to the material before it is structurally embossed.

Preferably the sheet material is made of commercial grade steel or aluminium, and the sheet material preferably has substantially uniform thickness.

The precise embossment pattern on the sheet material created by the structural embossing can take a wide variety of forms. For example, the embossing could create an array of separate individual deformations on the sheet or alternatively a series of elongate continuous deformations'or corrugations could be provided extending parallel to a deformation axis.

Preferably the array of said deformation axis is set at an angle to the longitudinal axis of the conduit. In particular, the deformation axis of the corrugations can be set parallel to the conduits longitudinal axis but alternatively it may be set transversely. The individual deformations of Mhe array pattern can have a variety of shapes in plan view. Thus these deformations could be of rectangular, circular, square or oblong shape in plan with other shapes possible. Further, deformations of different planar shape could be present in a particular array.

Thus the structural embossment of the sheet material improves the structural strength property of the metal sheet and hence of the complete ducting enabling a thinner sheet to be used with a consequent saving in material and hence in cost, or alternatively, for a given wall thickness, increased structural strength is imparted to the ducting.

The present invention can be applied in a wide variety of duct or conduit forms such as for example in straight duct sections, in corner and junction pieces and in vent outlets, for example roof cowls.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figs. 1 and 2 show schematic sectional views of two examples of closed conduits serving as ventilation ducting; Fig. 3 shows a plan view of parts of a ventilation duct system; Fig. 4 shows a sectional end view of a vent outlet in the form of a roof cowl; Fig. 5 shows one form of structural embossment suitable for use in the invention while Fig. 6 shows a sectional side view of a deformation through section X-X in Fig. 5.

Fig. 7 shows a variation of the embossment pattern shown in Fig. 5; and Fig. 8 shows another form of embossment pattern.

Referring to Figs. 1 and 2, ventilation ducting comprises a closed conduit 1 formed from metal sheet material, in Fig. 1 the conduit 1 being of rectangular cross section and constructed for example from bent sheet portions 1A, 1B which are overlapped and joined by welding at corners 2 while the conduit of Fig. 2 is of circular cross-section and can be formed by rolling a metal sheet and joining the sheet ends at an- overlap joint 3. The conduit 1 of Fig. 1 could have a square cross-section. A significant feature of the conduits 1 is that structural embossing is applied to the metal sheet material as shown schematically by reference E.

Fig. 3 shows a ventilation duct system using straight conduit sections 1 in accordance with either of Figs. 1 or 2, and there is also shown a duct corner piece 4 and a duct junction piece 5.

The pieces 4, 5 are also formed from sheet metal material and again embossment E applied to the material. The conduits 1 and pieces 4, 5 carry suitable flanges 6 to enable appropriate joining of the various duct parts.

Fig. 4 shows ducting in the form of a roof cowl 7 which extends longitudinally at the ridge of a building roof 8, the cowl 7 in fact being in accordance with the applicants U.K. Patent Application 8724382 (publication no.

The cowl 7 is built up from a series of inner sheet metal portions 9A, 9B and outer sheet metal portions 10A, 10B, and the cowl receives air via an outlet 0 at the roof ridge and discharges the air at discharge outlets D1, D2. The sheet metal portions of the cowl 7 are structurally embossed E in a like manner to the conduits 1 and vent members shown in Figs. 1-3.

In each of the above embodiments, the sheet material of the component comprises commercial or profiling quality steel or aluminium. Commercial or profiling quality steel would be satisfied by designations G1 and z2 of British Standards 2989 (1982) i.e. defined as low grade commercial or profiling quality steel. The steel will be suitably coated or galvanised.

The embossing E has the function of strengthening the sheet material and also strain hardening the material. The embossing may be applied substantially over the full area of the ducting component, but it would be possible for the embossing to be applied at only selected areas.

The actual embossment pattern can be chosen from a wide variety of different forms, and Figs. 5, 7 and 8 merely show examples. Thus in Fig.

5, the embossment applies an array of separate individual deformations 11, 12. As can be seen in Fig. 5 the deformations 11 are of oblong form in plan view while the deformations 12 are of a smaller circular shape, the pattern arrangement being defined by an orthogonal series of lines K-K, L-L with each circular deformation 12 surrounded by four oblong deformations 11. The spacing of the lines K-K, L-L specify the pitch of the deformation array: a pitch of 5 mm may be used for example. The structural embossing is achieved by a cold deformation using for example suitable embossment tool e.g. rollers, and it is a feature of the embossment that the orthogonal lines K-K, L-L are oblique to the rolling direc- tion R.

Where the embossing of Fig. 5 is applied to the sheet material forming the ducting, the longitudinal axis of the component (extending vertically out of the plane of the paper in Figs. 1-4) will correspond with the rolling axis R so that the deformation array 11, 12 will be oblique to the longitudinal axis of the ducting i.e. the orthogonal lines K-K, L-L will be oblique to this axis. It is also arranged that the thickness t (Fig. 6) of the sheet material remains substantially uniform over the area of the material even after the embossing process It will be understood that deformations of other planar shape could be presented in the array of Fig. 5 for example deformations of rectangular or square form could be used. Further, different patterns are possible such as for example a uniform array of similar deformations, and an irregular (non-uniform) deformation array is also possible.Fig. 7 shows an embossment pattern E generally similar to that of Fig. 5 but in this case two circular deformations 12 are surrounded by four oblong deformations 11.

Fig. 8 shows embossing E of corrugated form with nodes 13, 14 and the ratio of pitch P to valley depth H can be suitably chosen, the corrugations shown in Fig. 8 being of micro form. Fig. 8 shows a sinusoidal wave pattern but other wave patterns are of course possible. Where the ducting is provided with the corrugated embossment of Fig. 8, the axis of deformation (i.e. out of the plane of the paper in Fig. 8) of the embossment can be arranged appropriately relative to the longitudinal axis of the ducting.

For example, the profile deformation axis may be arranged longitudinally to the ductings longitudinal axis.

As a further alternative, different areas of the ducting could have different embossment patterns. In all cases it is preferred that the embossment has the effect of increasing a structural strength property e.g. bending resistance of the sheet material by at least 5 per cent.

Where a plastics coating is to be applied to the material the embossment may be carried out before or after the coating is applied.

The thickness of the metal sheet may be within the range 25 rrm to 5 mm for example and the ducting can have any suitable length.

The application of the embossment to the ducting in accordance with the present invention provides two distinct advantages concerning structural and aesthetic enhancement. Thus, the embossment increases the strength of the ducting and this will enable thinner sheet material to be used thereby lightening the ducting and consequently giving rise to a possible saving in cost since less metal is required. Also varying quality of metal material may be utilised as the strain hardening and cold deformation of the material due the embossment process mitigates against adverse effects created by the use of varying quality material.

Further, the embossing deformations will increase the corrosion resistance of the sheet material.

The deformations 11, 12 can be arranged to project so as to be visible externally and this can improve the aesthetic qualities of the ducting which is of particular value when the ducting is located externally. In the case of the corrugated embossment of Fig. 8, the weather face of the profile, for example the surface with nodes 13, can be suitably coated with synthetic material. The stronger structurally embossed ducting which consequently can be lighter will enable the use of lighter and cheaper structural steel work supporting frame for the ducting. Whereas the above embodiments are concerned with ventilation ducting, the ducting could be used for conveying other fluids e.g. liquids.

Claims

1. Fluid ducting comprising a conduit formed from metal sheet material which is structurally embossed so as to strengthen the material.

2. Fluid ducting as claimed in claim 1, wherein the structurally embossed sheet material has strength properties at least five per cent greater than the corresponding non-embossed plain sheet of a thickness equivalent to the material before it is structurally embossed.

3. Fluid ducting as claimed in claims 1 or 2, wherein the sheet material is made of commercial grade steel or aluminium.

4. Fluid ducting as claimed in any one of the preceding claims, wherein the sheet material preferably has substantially uniform thickness.

5. Fluid ducting as claimed in any one of the preceding claims, wherein the conduit is a closed-conduit produced by bending at least one metal sheet, and overlapping portion being present in the sheeting to facilitate jointing.

6. Fluid ducting as claimed in any one of claims 1 to 4, wherein the conduit is in the form of a roof cowl for buildings.

7. Fluid ducting as claimed in any one of the preceding claims, wherein the embossment provides an array of separate individual deformations on the sheet.

8. Fluid ducting as claimed in any one of claims 1 to 6, wherein the embossment comprises a series of elongate continuous deformations or corrugations.

9. Fluid ducting as claimed in claim 7 wherein the array#of separate deformations is arranged as a pattern having orthogonal axes and one of said axes is set at an angle to the longitudinal axis of the fluid ducting.

10. Fluid ducting as claimed in claim 8, wherein the continuous deformations or corrugations extend parallel to the longitudinal axis of the fluid ducting.

11. Fluid ducting as claimed in claim 8, wherein the continuous deformations or corrugations extend at an angle to the longitudinal axis of the fluid ducting.

12. Fluid ducting as claimed in claim 11, wherein the deformations or corrugations are set transversely to the longitudinal axis of the fluid ducting.

13. Fluid ducting as claimed in claim 7, wherein the deformations are of rectangular, circular, square or oblong shape in plan view.

14. Fluid ducting as claimed in claims 7 or 13, wherein the array includes deformations of different planar shape.

15. Fluid ducting as claimed in claims 7, 13 or 14, wherein at least some of the deformations are flat topped.

16. Fluid ducting as claimed in claim 7 or any one of the claims 13 to 15, wherein at least one deformation of the shape is surrounded by deformations or another shape.

17. Fluid ducting as claimed in any one of the preceding claims wherein the sheet metal material has a thickness on the range 0.25 mm to 5 mm.

18. Fluid ducting as claimed in any one of the preceding claims, wherein a coating is applied to the metal sheet.

19. Fluid ducting as claimed in claim 1, wherein the deformations of the embossment essentially project solely in an external direction.

20. Fluid ducting substantially as hereinbefore described with reference to and as illustrated in any one of Figs 1 to 4 including the embossment pattern shown in any one of Figs 5 to 8.