A METHOD OF MAKING A DUCT MEMBER

PROCEDE PERMETTANT DE REALISER UN ELEMENT DE CONDUITE

English Abstract

A method of making a duct member comprises feeding sheet metal continuously from a roll, progressively folding the opposite edges of the sheet as it advances to form a respective folded metal catch (14', 16') along each edge. Each catch includes an upstanding wall (102, 104) defining with the main body (106) of the sheet a shallow tray across the width of the sheet. A thermal insulator is dispensed in flowable form into the shallow tray as the sheet advances so that the thermal insulator spreads out to fill substantially the full width of the tray between the upstanding walls. The liquid thereafter solidifies to form a solid thermally insulating layer (110). The sheet is cut transversely into individual panels (100) having a respective catch along each edge for in-use push fit connection to a cooperating catch along the edge of an adjacent panel.

French Abstract

La présente invention a trait à un procédé permettant de réaliser un élément de conduite, lequel procédé comprend les étapes consistant à fournir en continu une tôle à partir d'un rouleau, à plier progressivement les bords opposés de la tôle à mesure qu'elle avance de manière à former une prise métallique pliée respective le long de chaque bord. Chaque prise inclut une paroi verticale qui définit avec le corps principal de la tôle un plateau peu profond d'un bout à l'autre de la largeur de la tôle. Un isolant thermique est distribué sous forme liquide dans le plateau peu profond à mesure que la tôle avance de sorte que l'isolant thermique se disperse de manière à remplir sensiblement la totalité de la largeur du plateau entre les parois verticales. Par la suite, le liquide se solidifie de manière à former une couche thermo-isolante solide. La tôle est découpée transversalement en panneaux individuels dotés d'une prise respective le long de chaque bord destinée à une connexion d'ajustage correct lors de l'utilisation à une prise de coopération le long du bord d'un panneau adjacent.

Claims

6
Claims
1. A method of making a duct member comprising feeding
sheet metal continuously from a roll, progressively folding
the opposite edges of the sheet as it advances to form a
respective folded metal catch along each edge, each catch
including an upstanding wall defining with the main body of
the sheet a shallow tray across the width of the sheet,
dispensing a thermal insulator in flowable form into the
shallow tray as the sheet advances so that the thermal
insulator spreads out to fill substantially the full width
of the tray between the upstanding walls, the liquid
thereafter solidifying to form a solid thermally insulating
layer, and cutting the sheet transversely into individual
panels having a respective catch along each edge for in-use
push fit connection to a cooperating catch along the edge
of an adjacent panel.
2. A method as claimed in claim 1, wherein the flowable
insulator comprises a liquid polymer which solidifies by
curing to form the solid insulating layer.
3. A method as claimed in claim 2, wherein the polymer is
liquid polyurethane.
4. A method as claimed in claim 1, further comprising:
fitting flanges to the transverse cut ends of each panel
for fixing each panel to the transverse cut end of an
adjacent panel.

Description

W02012/022594 CA 02807396 2013-02-
041 PCT/EP2011/062930
A Method of Making a Duct Member
Field of the Invention
This invention relates to a method of making a duct member,
i.e. a length of duct of which a number can be joined end
to end to form tubular ducting for, e.g., air and gas
distribution systems.
Background to the Invention
WO 2010/094385 (PCT/EP2010/000433) published on 26 August
2010 discloses a tubular duct member comprising a plurality
of sheet metal panels joined along adjacent longitudinal
edges by cooperating folded sheet metal catches. The
catches are pushed together such that respective detent
surfaces on each catch engage behind one another to retain
the edges of the sheets together. In some embodiments, an
insulating panel is fixed to the various panels of the duct
member.
It is an object of the present invention to provide an
improved method of making a duct member.
Summary of the Invention
The present invention provides a method of making a duct
member comprising feeding sheet metal continuously from a
roll, progressively folding the opposite edges of the sheet
as it advances to form a respective folded metal catch
along each edge, each catch including an upstanding wall
defining with the main body of the sheet a shallow tray

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across the width of the sheet, dispensing a thermal
insulator in flowable form into the shallow tray as the
sheet advances so that the thermal insulator spreads out to
fill substantially the full width of the tray between the
upstanding walls, the liquid thereafter solidifying to form
a solid thermally insulating layer, and cutting the sheet
transversely into individual panels having a respective
catch along each edge for in-use push fit connection to a
cooperating catch along the edge of an adjacent panel.
Brief Description of the Drawings
Embodiments of the invention will now be described, by way
of example, with reference to the accompanying drawings, in
which:
Figure 1 shows a duct panel produced according to an
embodiment of the present invention.
Figures 2 and 2(a) show detailed views of assembled ducting
including the duct panels of Figure 1.
Description of Embodiments of the Invention
Figure 1 shows a duct panel produced according to an
embodiment of the present invention. Figure 1(a) is an
underneath plan view of a duct panel 100, Figure 1(b) is a
cross-section on the line B-B of Figure 1(a), and Figure
1(c) is an enlarged cross-section similar to Figure 1(b).
As in WO 2010/094385 Figure 8, the panel 100 has male and
female catches respectively running along opposite parallel

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edges. These catches are constructed and operate generally
the same as the male and female catches 14', 16' of WO
2010/094385 Figure 8 and, accordingly, the same reference
numerals have been applied. The following description will
concentrate on the differences from WO 2010/094385, the
basic operation of the catches being assumed.
The main difference is that each catch 14', 16' includes a
respective upstanding wall 102, 104 formed by additional
folding of the sheet metal at each edge of the panel
through two 90 degree bends and one 180 degree bend, as
shown in Figure 1(c). These walls 102 and 104, together
with the main body 106 of the panel 100 as a base, form a
shallow tray across the width of the panel.
The panels 100 are produced continuously from a roll of
sheet metal, the edges of the sheet being progressively
folded as the sheet advances from the roll to form the
catches 14', 16' and the upstanding walls 102, 104, the
sheet then being cut transversely into individual panels.
However, after the folding of the catches and the
upstanding walls, but before the sheet is cut into
individual panels, a liquid polyurethane (LPU) is
continuously dispensed into the shallow tray formed by the
walls 102, 104 and the metal sheet. This flows sideways to
fill the full width of the tray between the walls 102, 104
and rapidly cures (within minutes) to form a solid
insulating layer 110. Longitudinal and transverse
strengthening ribs 112 are formed in each panel by pressing
before the application of the LPU. Finally, end flanges
118 as shown in the assembly drawing of Figure 2 and the
detailed view of Figure 2(a), serving the same purpose as

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the integral flanges 18 in WO 2010/094385 Figures 1 to 4,
are riveted (or alternatively spot welded) to the
transverse cut ends of each panel for fixing each panel to
an adjacent panel.
In the preceding embodiment a hard polymer lining 114 is
optionally sprayed onto the exposed surface of the
foam/insulating layer 110, Figure 1. This has two
advantages. First, it provides a hardened surface which
serves to protect the underlying layer 110 when the ducts
are being cleaned. Second, although the layer 110 has a
certain amount of flame resistance, it can still be
flammable. The hard polymer lining is a flame retardant,
and provides a higher fire resistance than the underlying
material. The hard polymer layer 114 has a thickness of
about 3mm, but could range in thickness from about 0.5mm,
in contrast with the layer 110 which is typically 32mm-35mm
thick but could be up to around 45mm thick. The flame
retardant polymer 114 is preferably of the type produced by
BASF under the mark Elastocoat C6325/105; or by Bollom Fire
Protection (UK) under the mark BroFlame.
In embodiments of the invention where the assembled
ducting, for example as shown in Figures 2 and 2(a),
includes an insulating layer 110 possibly coated with a
polymer lining 114, a durable and relatively impervious
internal lining is provided, by comparison with using for
example Rockwool or equivalent as an insulator either
within or around the ducting. This layer/lining does not
accommodate rodents or harbour or promote the spread of
bacteria, such as Legionella as readily as prior art
systems. At the same time, the ducting can be transported

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in flat packed form and when assembled can provide a
relatively airtight conduit for use in many applications.
In addition or as an alternative to the layer 114, an anti-
microbial layer (not shown) can be added to the insulating
layer 110. One suitable coating is produced by General
Paints Ltd of Celbridge, Ireland under the mark Hygen
Ultra.
The invention is not limited to the embodiments described
herein which may be modified or varied without departing
from the scope of the invention.

Representative Drawing