GB2173837A - Wall ducts - Google Patents

Abstract

A wall duct 10 comprises a conduit body 18,26,36 which has a frontal opening masked by a grille 12, a water outlet 20 in its underside adjacent its front, and internal baffles 32,34. In use, the duct is wedged (30) in the outer skin 14 of a cavity wall. It serves for both drainage and ventilation of the cavity, replacing separate weep holes and vents. Water from within the cavity, e.g. from a cavity tray 40, drains along the conduit body and escapes through the outlet 20. Air passes through the grille 12 to ventilate the cavity. The baffles 32,34 prevent wind from stopping the escape of water. <IMAGE>

Description

SPECIFICATION Wall ducts The present invention relates to ducts for extending through walls.

In conventional cavity walls there are various openings in the outer skin. An opening is convenienty provided by a duct interposed between two horizontally adjacent bricks (or other building units). Thus for ventilating the cavity (which is particularly important with timber framed constructions) it is now normal to have at least one such duct every 1.5m of wall (in the width direction). A ventilator duct may be a simple tube of rectangular section, with a grille at one end to keep out insects.

Ducts are also required to let water escape, e.g. from a cavity tray. A weep hole duct may be a simple tube. But wind tends to prevent water from escaping, and debris tends to collect and dam the flow. A better type of duct projects forwardly from the wall and has a water outlet opening in its underside. The outer end is closed to provide shelter from wind.

The present invention provides a wall duct suitable for use both as a ventilator and as a weep hole duct. Preferably it has at least some of the following features: a body for defining a conduit which in use projects forwardly from the wall, and which has a water outlet in its underside at the front; a frontal opening having a grille; at least one internal baffle to deflect incoming wind and reduce the ingress of rain, and preferably at least two such baffles, one behind the other, each extending from a different one of the opposite lateral sides of the duct and stopping short of the other such side; external wedge formations so that the duct can be pushed into an existing gap.

A particularly preferred duct has a frontal opening substantially partitioned off from a water outlet by a baffle assembly.

A wall duct may comprise a plastics moulding. This may provide the conduit body, a front face having a grille, and one or more baffles. A duct may be formed from two tray portions hingedly connected and snap-engageable to define a tubular duct.

The body of the duct may not define a tubular conduit by itself. For example it could provide part of a tube, e.g. being open at one side and possibly above. In effect the tube would be completed by parts of the wall.

A wall duct may also be extended in length by connection of another piece of tubing (which may be a push-fit). This may be useful when a duct is to serve for ventilating through both skins of a cavity wall.

Embodiments of the invention will now be described in greater detail by way of example with reference to the accompanying drawings in which: Figure 1 is a vertical section through a front skin of a cavity wall with a cavity tray and a wall duct embodying the invention; Figure 2 is a front elevation of the duct; Figure 3 is a side elevation of the duct on a smaller scale; Figure 4 is an underneath plan; Figure 5 is a section on V-V in Fig. 2, on a large scale; Figure 6 is a front elevation of an unfolded carcase; Figure 7 is a section on A-A; and Figure 8 is a perspective view of a second embodiment.

The duct 10 of Figs. 1 to 7 is plastics tube of generally rectangular section, open at the rear and having a grille 12 at the front.

The length of the duct 10 is about the same as the thickness of the outer skin 14 of a wall, but the grille face 12 is angled such that the bottom edge 16 projects somewhat, thus exposing part of the bottom face 18 which has an aperture 20. The grille face 12 may, as shown, have a central upright spine 22 from which lateral grille portions 24 extend rearwardly to meet the side walls 26, the grille portions 24 are apertured except for a lower region 28. The side walls 26 have wedge formations 30 that project laterally to an increasing extent towards the front.

internally each side wall 26 bears a respective baffle 32,34 which extends almost to the other side wall 26. The rear baffle 32 extends from the top face 36 downwardly and forwardly, almost to the bottom face 18. The front baffle 34 extends parallel to the rear one for most of its length, but a final portion 35 extends substantially horizontally to join the grille face 12 at the top of the lower region 28. Thus as can be seen from Fig. 1, water (e.g. collected by a cavity tray 40 has an unobstructed path along the bottom 18 of the duct. It is substantially shielded from wind blowing in through the grille 12 by the baffles 32,34, particularly by the final portion 35 of the front baffle which virtually walls off the grille, so that the air and water paths are distinct. Any rain carried in by wind impinges on the baffles, whose slope leads it forwardly out of the duct.

The duct may be a unitary plastics moulding, formed in the opened-out configuration shown in Figs. 6 and 7. These show a pair of trays 42,44 each having peripheral walls 46,48,50 on three sides. The walls 50 which constitute the bottom face 18 are integrally connected at their tops to form a plastics hinge 52, about which the moulding can be flexed to bring corresponding walls into alignment to create the tubular duct. As shown in Fig. 5 the interrupted wall portions 48 that constitute the grille face 12 have cooperating tongue-and-groove formations 56.

Complementary pairs of pillars 58 project from the side walls 26 and have formations 60,62 for mutual snap-engagement to hold the duct in its tubular configuration. (They may be releasable e.g. to allow the duct to be cleaned out.) Conventionally, ducts are incorporated into a wall as it is built. While the present duct can certainly be used thus, we prefer to leave openings, or create them, and then insert ducts. The wedges 30 help to lock them in position. Such insertion can of course be used to improve existing structures. For new structures it avoids the risk that building operations subsequent to the installation of a duct will choke it with debris such as mortar. Of course, even if debris should coilect and choke the aperture 20, not much water will accumulate since the grille face 12 provides an overflow outlet.

Fig. 8 shows a simplified duct 110, which can be produced more cheaply. It is similar to the duct as shown in Figs. 1 to 3 (and corresponding elements have the same reference numerals raised by 100) but differs in that it has only a single side wall 126 and consequently has a different baffle arrangement, both baffles 132,134 extending from the one side wall 126. The baffles may be of the same width as the duct so that when it is installed in a wall, an adjacent portion of that wall serves as the "missing" side wall of the duct, and the baffles terminate adjacent it.

The front, upper baffle 134 extends from the top face 136 downwardly and forwardly for about 1/3 or 1/2 of the height of the duct. The rear, lower baffle 132 starts above the bottom edge of the upper baffle 134 and extends first rearwardly then forwardly (so that wind is not funnelled rearwardly). It terminates slightly above the bottom face 118 to leave a gap for the outward flow of water.

The duct may be formed from a grille piece 112 and a single moulding which provides the rest of the structure.

Of course, ducts according to the invention need not be just as described above. But it is desirable to keep such features as: the angling of the front face 12 from top to bottom and of the portions 24 (which extend rearwardly and laterally, thus increasing the grille area); and the baffle arrangement (which produces regions of raised and lowered air pressure to encourage water discharge).

Ducts could be produced by adding components to extruded tubing. The baffles and grille face could be provided by one or more separate members.

Extension tubes may be provided for coupling to the rear open ends of ducts, preferably by a simple push-fit. This would enable ducts to be used where a longer overall length of duct is required, e.g. in thicker walls and as general purpose ventilators to vent from the outside to the inside of the building. If a particularly long duct is required, it may be provided by a plurality of extension tubes of normal length fitted end to end.

Claims (14)

1. A wall duct comprising a body for defining a conduit, the body having a frontal opening and a water outlet in its underside adjacent the front, the frontal opening having a grille; and there being an internal baffle to reduce the passage of wind and rain into the duct through the frontal opening.

2. A wall duct according to claim 1 wherein the frontal opening is substantially partitioned off from the water outlet by the baffle.

3. A wall duct according to claim 1 having two baffles, one generally behind the other, and staggered so as to define a non-straight air path.

4. A wall duct according to claim 3 wherein the conduit body has opposed lateral sides and there are at least two baffles, each extending from a different one of the opposite lateral sides and stopping short of the other such side so that they are staggered in a horizontal sense.

5. A wall duct according to Claim 3 wherein the baffles are vertically staggered, extending from adjacent upper and lower faces of the duct respectively.

6. A wall duct according to any preceding claim wherein external wedge formations project outwardly from external sides of the duct to facilitate engagement in a gap in a wall.

7. A wall duct according to any one of the preceding claims wherein the frontal opening is inclined, extending farther forward at the bottom.

8. A wall duct according to any one of the preceding claims wherein the grille is forwardly convex.

9. A wall duct according to any one of the preceding claims further including an extension tube connectable to the duct to extend away from its rear end.

10. A wall duct according to any one of the preceding claims formed from two plastics moulded tray portions.

11. A wall duct according to claim 10 wherein the two tray portions are hingedly connected along respective edges so as to be pivotable from a coplanar configuration to the configuration in which they provide the conduit body.

12. A wall duct according to claim 11 wherein the two tray portions are releasably engaged in the conduit body configuration.

13. A wall duct according to any one of claims 1 to 9 wherein the conduit body comprises an extruded tube section.

14. A wall duct substantially as described herein with reference to the accompanying drawings.