GB2034879A - Improvements in or relating to ventilators - Google Patents

Abstract

A ventilator, to be mounted on the roof of a building, has a downwardly-tapering air-flow chamber, a central drainage channel 3 running, lengthwise between the end plates of this chamber, and at least two pairs of symmetrical pivotable damper blades 5, 5a and 6, 6a which when open allow unimpeded airflow from the chamber to the atmosphere and when closed direct water falling on them towards the central drainage channel. Blades 5, 5a may be of transparent material. Pivoting of the blades may be effected manually or automatically. Details of mounting the ventilator on the roof are illustrated in Figs. 3 and 4 (not shown). <IMAGE>

Description

SPECIFICATION Improvements in or relating to ventilators This invention relates to ventilators for buildings and more particularly to a ventilator of the "natural" or "gravity" type i.e. where ventilation is by means of hydrostatic pressure arising from heat produced in the interior of a building such as a workshop or factory.

A large number of industrial buildings are constructed from a structural steel framework clad with coated steel or aluminium or asbestos sheets.

These buildings are used as warehouses, workshops, stores and factories for industrial operations. There is clearly a requirement for efficient and simple ventilators for such buildings which should inter alia, satisfy the following criteria.

(a) simple site assembly.

(b) reduction of the total number of compo nents on site, (c) weights, sizes and stability of components suitable for site transport and handling, (d) avoidance of critical details dependent upon an assumed standard of site workmanship, e.g.

use of mastic sealing.

It is an object of this invention to provide a ventilator for mounting on the roof of a building which satisifies the above criteria, which is robust, simple of operation, easy to assemble and requires the minimum number of component parts.

This invention consists in a ventilator, for mounting on the roof of a building, comprising two downwardly-tapering end-plates and a downwardly-tapering housing, together defining an air flow chamber, open at top and bottom, a drainage channel running length-wise between the two end plates, at least two damper blades symmetrically mounted on each side of the drainage channel, and laterally displaced with respect to one another, for rotation about horizontal axes between open and closed positions, whereby in their open positions the damper blades allow substantially unimpeded air flow from the flow chamber to the atmosphere, while in their closed position the damper blades overlap to form inclined surfaces to direct water falling on them toward the drainage channel.

Preferably the housing is shaped so as to provide a suction zone at the outlet of the air flow chamber.

Preferably the damper blades are gravity biassed towards the open position and are held closed by actuating means.

Preferably subsidiary drainage channels are provided on the inner surfaces of the end plates.

Preferably these slope away from the centre of the air-flow chamber and towards the inner surface of the housing.

Preferably a horizontal drainage channel is mounted below the sloping subsidiary drainage channels.

Preferably the end plates are attached to a substantially rectangular base frame which is adapted to be attached to the roofing sheets of a building above a ventilation aperture in said roof sheets.

This base frame is preferably attached to roofing sheets by means of "hinges" which allow for variation of angle between ventilator and roofing sheets.

Preferably there are four blades, two on each side of the central channel.

Preferably the rotation of the damper blades is actuated by means of cords or wires which may be manually operated. Alternatively the rotation of the blades may be controlled by automatic means e.g. pneumatic or hydraulic cylinders and may be combined with a "thermal link" arrangement whereby, in the event of fire, the vanes or dampers fall into their open position due to this link being broken.

Preferably the innermost pair of damper blades are fabricated of a reinforced transparent or translucent plastics material e.g. wire-reinforced clear PVC sheet, such as that sold under the trade name DARVIC (R.T.M.) so that light can enter the building via this material when the vanes are in their closed positions.

Preferably the blades are moveable in pairs, the innermost pair being rotated together independently of the other pair or pairs.

Thus the ventilator according to the invention may be used in the following four modes.

(a) as a normal ventilator with the innermost pair of damper blades closed and the others open (b) as an increased air-flow ventilator with both pairs of blades in their open position (c) as a fire ventilator where a thermal - link is incorporated into the actuating means for one or both pairs of blades.

(d) as a roof light where the inner pair of blades is made of transparent material.

The invention will be further described by reference to the following specific description with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of a ventilator according to the invention.

Figure 2 is an sectional view of an end plate for the ventilator of Figure 1.

Figure 3 is an isometric view of a base plate for mounting a ventilator according to the invention on a roof.

Figure 4 is a diagrammatic drawing showing a hinge for attaching a base plate to roofing sheets.

With reference to Figures 1 and 2 the ventilator is made up of two end-plates 1 of the general shape shown in Figure 1 , together with the tapering housing shell 2, shown in section in Figure 2. Running down the centre of the ventilator between end-plates 1 is the channel section 3 which is let into recesses 4 in end-plates 1 and attached thereto by suitable fasteners. Two pairs of rotatable blades 5, 5a and 6, 6a are mounted symmetrically on either side of the central drainage channel 3. These blades are rotatable about horizontal axes shown (in Figure 1) as spindles 7 and 8. Thus blades 5, 5a and 6, 6a are rotatable between the closed positions as shown for the outermost blades in Figure 1 and the open positions as shown for the innermost blades in Figure 1.Mounted below the channel 3 (Figure 1) are subsidiary inclined drainage channels 9, 9a which are attached to the inner surfaces of end-plates 1 (as shown in Fig. 2) and below these again runs the horizontal drainage channel 10 (Figure 2). both of these feed drainage water into the bottom corners 11 of housing 2 from where it is run off to waste.

The mounting of the ventilator on the roofing sheets is achieved by means of the rectangular base plate shown in Figures 1 and 3. The base plate (Figure 3) has a rectangular lower flange configuration 12, upwardly tapering side walls 13 and upper flanges 14. This base plate may be attached direct to roofing sheets or by means of the hinges shown in Figure 4. The end-plates 1 are attached to the base plate by means of fasteners shown diagrammatically at 1 5. The central channel 3 and housing 2 is then attached to this assembly of base and end-plates.

As an example of the attachment of the base plate to roofing sheets sloping away from the ventilator, as in a ridge ventilator, the hinges (18) shown in Figure 4 may be used to form a connection between base plate 1 6 and sloping roofing sheets 1 7. The hinges are rotatable so as the accommodate any roof slope from 0 (horizontal) to 600 to the horizontal. Thus the ventilator is adaptable to be fitted to flat or pitched roofs.

In operation, warm air rising through an aperture in the roof of a building enters the air flow chamber defined by end plates 1 and housing shell 2, via the central aperture in the base plate 1 6. Air can then flow freely through the chamber and out to atmosphere when the blades are in their open position (as shown by innermost blades in Figure 1) or the ventilator may be closed off by setting the blades to their closed position (as shown by outer blades in Figure 1). As pairs of blades are independently operable, part of the whole of the air-flow area available may be utilized. Where the inner blades 5, 5a are made of transparent material the ventilator may act as a roof-light even with the blades in their closed position. The actuating means for rotating blades 5, 5a and 6, 6a may incorporate a thermal link which will allow the blades to return to their open position under the influence of gravity when the link is broken. Thus ventilator allows normal or enhanced ventilation and may also be used as a roof light or a fire-ventilator, or as a combination of any of these.

When used in a "normal" ventilation mode i.e.

with the innermost pair of blades closed and the others open, the ventilator is still completely weather-tight, since water falling on the inner blades will be drained into the central channel.

Ventilators according to the invention may be used as individual units or abutted together to form a continuous run of ventilator on the roof of a building, either at the ridge or on a sloping roof.

Claims (14)

1. A ventilator, for mounting on the roof of a building, comprising two downwardly-tapering end plates and a downwardly-tapering housing, together defining an air-flow chamber which is open at top and bottom, a drainage- channel running lengthwise between the two end-plates, at least two damper blades symmetrically mounted on each side of the drainage channel and laterally displaced with respect to one another, for rotation about horizontal axes between open and closed poSitions, whereby in their open positions the damper blades allow substantially unimpeded air flow from the flow chamber to the atmosphere, while in their closed position the damper blades overlap to form inclined surfaces to direct water falling on them towards the drainage channel.

2. A ventilator, as claimed in claim 1, wherein the housing is shaped so as to provide a suction zone at the outlet of the air-flow chamber.

3. A ventilator, as claimed in claim 1, wherein the damper blades are gravity-biassed towards the open position and may be held closed by actuating means.

4. A ventilator as claimed in claims 1-3 in which subsidiary inclined drainage channels, sloping from the centre of the airflow chamber towards the inner surface of the housing, are mounted on the inner surfaces of the end-plates.

5. A ventilator as claimed in claim 4 wherein a horizontal drainage channel is mounted below the subsidiary inclined drainage channels.

6. A ventilator as claimed in claim 1, wherein the-end-plates are attached to a substantially rectangualr base frame which is adapted to be attached to roofing sheets of a building, above a ventilation aperture.

7. A ventilator as claimed in claim 6, wherein the base frame is attached to the roofing sheets by means of hinges which allow for variation of angle between the base-plate and the roofing sheets.

8. A ventilator as claimed in claim 1 which has four blades, two blades being mounted on each side of the main drainage channel.

9. A ventilator as claimed in claim 5 and 3, in which the actuating means take the form of cords or wires which may be manually operated.

10. A ventilator as claimed in claims 1 and 3 wherein the actuating means takes the form of pneumatic or hydraulic cylinders with pistons.

1 A ventilator as claimed in claims 1 and 3 in which the actuating means incorporates a "thermal link" arrangement, whereby in the event of fire the damper blades fall into their open oositions due to the link being broken.

12. A ventilator as claimed in claims 1 or 8, wherein the innermost pair of damper blades is fabricated form transparent or translucent plastics material.

1 3. A ventilator as claimed in claims 1 or 8 wherein the blades are rotatable in pairs, the innermost pair nearest to the main drainage channel, being rotated together independently of other pair or pairs.

14. A ventilator, for mounting on the roof of a building, substantially as hereinbefore described with reference to Figures 1, 2 and 3 of the accompanying drawings.