GB2283312A - A wall-mounted ventilator - Google Patents

Abstract

A ventilator has a duct (4) interconnecting internal and external air vents (2, 3). The external vent (3) comprises parallel baffle plates (11) dividing the incoming air into a plurality of streams. The outlet (12A) of at least one of the streams is directed in a counterflow manner with respect to at least some (eg 12D) of the remainder of the streams to create turbulence. The internal vent (2) comprises a rear plate (14), the inner edge regions of which overlap the inner diameter of duct (4a). The vent (2) also comprises a front plate (15) having a slot-shaped air outlet (16). Turbulence in the ventilator increases with increasing air flow velocity. <IMAGE>

Description

A VENTILATOR This invention relates to a ventilator and more particularly to a ventilator of the kind required for ventilating rooms containing gas appliances.

It is well known that air consumed by gas appliances requires to be replaced and traditionally air bricks have been used for this purpose. A conventional air brick provides a direct connection between the room interior and the external atmosphere. Air is drawn into the room through the air brick as the gas appliance operates. A disadvantage of the conventional air brick is that it may produce drafts particularly when the outer face of the air brick is subject to high winds.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantage.

According to the present invention there is provided a ventilator comprising a duct interconnecting internal and external air vents characterised in that the external vent is adapted to guide incoming air in a plurality of streams directed in counterflow at an inlet region of the duct so as to create increasing turbulence with increasing air flow velocity.

Preferably, the external vent has parallel side walls and a plurality of baffle plates parallel thereto for guiding the incoming air as aforesaid in a plurality of channels at least some of which have at least partly opposed outlets in the inlet region of the duct.

The inlet of the external vent is preferably directed downwardly in use.

The internal vent may comprise spaced front and rear plates defining lateral air openings therebetween and the rear plate of the internal vent preferably projects into the flow cross section of the duct so as to create turbulent flow in this region. The front plate of the internal vent preferably has a central air outlet slot.

The interconnecting duct of the ventilator may be telescopic to enable it to be adjusted to suit different wall thicknesses.

The invention will now be further described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic prospective view of one embodiment of ventilator in accordance with the invention; Fig. 2 is an internal end elevation in the direction of arrow A of Fig. 1; Fig. 3 is an external end elevation in the direction of the arrow B of Fig. 1; Fig. 4 is a diagrammatic cross section of the ventilator in position in a cavity wall, and Figs. 5 and 6 show modified inner and outer vents of the ventilator.

Referring now to Figs. 1 to 4, a ventilator generally indicated at 1 comprises inner and outer vents 2, 3 interconnected by a duct 4.

The ventilator 1 may be moulded in synthetic plastics material or fabricated in sheet metal but in either case it has a two-part construction with one part comprising the inner vent 2 and a front part 4a of the duct 4 and the other part comprising the external vent 3 and a rear part 4b of the duct 4. The front part 4a of the duct 4 is a telescopic sliding fit in the rear part 4b so as to permit the duct 4 to be adjusted in length to suit different wall thicknesses. Fig. 4 shows the ventilator 1 mounted in position in a cavity wall comprising an outer leaf 5 spaced from an inner leaf 6 by a cavity 7.

The external vent 3 has a generally rectangular box shape with a downwardly directed air inlet opening 8. The front and rear walls 9, 10 of the vent 3 are in parallel arrangement with each other and with three internal baffle plates 11 defining four equal width air flow channels 12 for containing four upflowing air streams as indicated by the arrows in Fig. 4. The rear wall 10 and the outermost baffle plate 11 are inclined forwardly at their upper ends and the upper edge of the baffle plate 11 is spaced from the front wall 9 so as to define therewith an outlet 12a extending across the width of the vent 3 and directed downwardly. The next adjacent channel 12 has an outlet 12b inclined forwardly and downwardly and the next adjacent channel 12 has an outlet 12c inclined forwardly and upwardly.The innermost channel 12 has an outlet 12d below the outlet 12c and inclined forwardly and upwardly. The channel outlets 12a-d thus face in different directions towards an inlet region 13 of the duct 4. The respective air streams are therefore directed in counterflow as indicated by the arrows in the region 13. In particular, it will be noted that the outlet 12a is directly opposed to the outlets 12c and 12d and partially opposed to the outlet 12b.

The air outlet vent 2 at the front end of the duct 4 comprises a rear plate 14 of rectangular shape with a rectangular central opening positioned centrally of the duct 4 so that the inner edge regions of the plate 14 overlap the flow cross section of the duct 4 thereby creating turbulence in these regions as indicated by the arrows in Fig. 4. The vent 2 also comprises a front plate 15 fixedly spaced from the rear plate 14 so as to provide edge outlets at the four sides of the vent 2 for laterally directed air streams two of which are indicated by the upwardly and downwardly directed arrows in Fig. 4. Since such air streams are directed generally parallel to the inner surface of the wall 6 drafts caused by the incoming air will be reduced. In addition, the vent 2 has a horizontal, slot-shaped air outlet 16 centrally of the front plate 15 thereof as shown particularly in Figs. 2 and 4.

When fitted in the position shown in Fig. 4, the air flow characteristics depend upon the ambient atmospheric conditions.

Assuming quiet atmospheric conditions in the vicinity of the air vent 3, replacement air is drawn through the ventilator according to the demand of the gas appliance in a relatively smooth flow in the direction of the arrows, i.e. without significant turbulence. The air passes through the channels 12 in the external vent 3, via the outlets 12a-d into the inlet region of the duct 4, along the duct 4 and out into the room through the internal vent 2. In windy conditions, a greater volume of air is forced into the inlet 8 of the external vent 3 but in this case air entering the inlet region of the duct 4 via the outlets 12a-d is subjected to significant turbulence which has the effect of reducing the flow velocity through the duct 4. Turbulence at the outlet end of the duct 4 in the region of the rear plate 14 of the internal vent 2 is also increased.Turbulence at these -locations increases with increasing air flow velocity through the external vent 3.

Figs. 5 and 6 illustrate alternative designs of the internal and external vents 20, 30 respectively. The internal vent 20 is of similar design to the vent 2 save that the front and rear walls are of circular configuration. The external vent 30 is of semi-cylindrical configuration with a downwardly directed inlet opening as in the vent 3. In both cases, the vent 20, 30 is connected to telescopically interfitting duct parts 40a, 40b of circular as opposed to rectangular shape in cross section.

It will be appreciated that numerous modifications may be made without departing from the scope of the invention. For example, the interconnecting duct may be of any desired cross sectional configuration and need not be adjustable in length. The internal vent may be of alternative design as may be the external vent of which the opening may also be directed upwardly or laterally although a downward orientation is preferred. The number of air channels in the external vent 3 may be varied but there must be at least two such channels, which may however be of different dimensions, terminating in an inlet region of the duct with their outlets into said region being fully opposed (i.e. in spaced parallel relationship) or partly opposed (i.e. facing in non-parallel relationship) such that the emerging air streams are directed in counter flow towards each other so as to create increasing turbulence with increasing air flow velocity.

Claims (8)

CLAIMS:

1. A ventilator comprising a duct interconnecting internal and external air vents characterised in that the external vent is adapted to guide incoming air in a plurality of streams directed in counterflow at an inlet region of the duct so as to create increasing turbulence with increasing air flow velocity.

2. A ventilator as claimed in claim 1, wherein the external vent has parallel side walls and a plurality of baffle plates parallel thereto for guiding the incoming air as aforesaid in a plurality of channels at least some of which have at least partly opposed outlets in the inlet region of the duct.

3. A ventilator as claimed in claim 1 or 2, wherein the inlet of the external vent is directed downwardly in use.

4. A ventilator as claimed in any one of claims 1 to 3, wherein the internal vent comprises spaced front and rear plates defining lateral air openings therebetween.

5. A ventilator as claimed in claim 4, wherein the rear plate of the internal vent projects into the flow cross section of the duct so as to create- turbulent flow in this region.

6. A ventilator as claimed in claim 4 or 5, wherein the front plate of the internal vent has a central air outlet slot.

7. A ventilator as claimed in any one of the preceding claims, wherein the duct is telescopic to enable it to be adjusted to suit different wall thicknesses.

8. A ventilator substantially as herein described with reference to the accompanying drawings.