GB2293234A - Ventilator - Google Patents

Abstract

A ventilator for a room having an outside cavity wall has a centrally extending baffle 16 and a pair of edge baffles 17, 18 which overlap the central baffle to provide a meandering path for air whilst preventing passage of light and minimising draughts and noise. The baffles are formed on collars 15, adjacent collars alternating so that like baffles abut. The collars are inserted into a housing (spigot 21, Fig 2 not shown) which fits inside a liner bridging the cavity wall. <IMAGE>

Description

VENTILATION DEVICE The present invention relates to a ventilation device for a ventilation opening, wherein the opening is defined by a substantially rectangular liner.

In older properties, lack ofventilation did not cause a problem because most of these properties were far from air-tight and a significant amount of air could be made available to satisfy all combustion needs. Thus, combustion appliances, such as coal fires and more modern heating systems, burning oil or gas, were provided with sufficient air, given that the combustion process tends to draw fresh air into the combustion area as hot flue gases are drawn up a suitable outlet, such as a chimney.

More recently, the trend with modern buildings is to provide improved insulation and draught prevention. In addition, there has also been a trend towards reducing draughts in existing houses because these can reduce the heating efficiency of heating systems and cause annoying air currents within the property itself. Thus, a balance has to be met between requirements to reduce unwanted air currents while at the same time providing sufficient ventilation for combustion processes.

In addition to draught prevention, windows and doors have also tended to become more secure and airtight as additional provisions have been made for security reasons. Thus, it is generally assumed with modern buildings that, unless special provisions are made, insufficient air will be available for most combustion appliances.

As previously stated, while a combustion appliance is in operation it will tend to draw air through static ventilation systems which, given noise, reliability and cost constraints, are generally preferred to dynamic passive systems, such as passive fans, or active motorised fan systems where reliability constraints become particularly signif cant.

British standards, for example, generall require ventilation for heating appliances to be provided with no moving parts (especially motors) to ensure reliability of operation. The standard also specifies the size of openings, thereby ensuring that these openings do not become blocked by dust accumulation etc.

British regulations state that appliances in a room can have a combined power output of 7kw before additional ventilation is required.

However, once this value is exceeded, as it will be for most gas fires and boilers etc, ventilation devices must be provided, to ensure that the appliance receives sufficient air for combustion purposes.

A known problem with static ventilation systems, having no motorised components and no moving parts, is that pressure changes will occur between the outside and inside of the property, which will tend to blow air or suck air through the easiest passage, and specifically that provided by the ventilator.

Furthermore, warm air rising within the property itself will also tend to cause cold air to be sucked in through the ventilator. Thus, static ventilators tend to provide excessive ventilation, in addition to that required for combustion purposes.

Another problem with static ventilation systems is that openings which allow air to pass there through may also allow light to pass, in addition to providing an access route for scavenging animals and insects. Furthermore, light from inside the dwelling will attract some species of insects. In such circumstances, it is know to provide a cowl on the outside of a ventilator which will reduce intrusions of this type. However, in many existing dwellings, ventilation systems are provided in positions at which an extending cowl could be damaged, either inadvertently or purposefully.

A problem therefore exists in providing a static ventilation system which provides a passage for fresh air from the outside of a building into the inside of the building, particularly so as to provide air for combustion purposes. At the same time, there should be no externally fitted cowl but the ventilation system should be impervious to animals, insects and external light.

Furthermore, although the ventilation system should provide a clear path for drawn air to be sucked there through, in order to provide air to combustion appliances, the ventilation system should provide resistance to externally blown air, so that external gusts of wind are reeduced, thereby reducing internal draughts.

According to a first aspect of the present invention, there is provided a ventilation device for a ventilation opening, wherein said opening is defined by a substantially rectangular lining means, comprising a centrally extending baffle positionable within said lining means so as to be substantially normal to the ventilation direction, and a pair of edge baffles positionable within said lining means so as to be substantially normal to the ventilation direction, wherein said centrally extending baffle is displaced from said edge baffles in the ventilation direction but overlaps said edge baffles in the plane normal to said direction.

In a preferred embodiment, a grille is connectable over an indoor opening of a spigot, forming part of the lining means.

According to a second aspect of the invention, there is provided a method of ventilating a room via an outside cavity wall, comprising steps of establishing an opening of specified size in both sub-walls ofsaid cavity wall; positioning substantially rectangular lining means within said opening; positioning a centrally extending baffle within said lining means so as to be substantially normal to the ventilation direction; and positioning a pair of edge baffles within said lining means so as to be substantially normal to the ventilation direction, wherein said centrally extending baffle is displaced from said edge baffle in the ventilation direction but overlaps said edge baffle in the plane normal to said direction.

The invention will be described by way ofexample only, with reference to the accompanying drawings, in which: Figure 1 shows a plurality of collars, each having a centrally extending baffle and a pair of edge baffles; Figure 2 illustrates a top view of the collars shown in Figure 1, engageable within a rectangular spigot for insertion within a rectangular liner of a ventilation opening.

Figure 3 shows a perspective view of three collars being aligned for insertion within a rectangular spigot; and Figure 4 shows the collars illustrated in Figure 3 being inserted within the spigot.

The preferred embodiment is particularly directed towards providing a ventilation device within a ventilation opening ofnine inches across and six inches down. Thus, in a vertical wall, such an opening would take up two brick spaces and may be covered by an air brick on an outer surface and a grille on an inner surface.

The ventilation opening is defined by a rectangular liner which extends from said outer surface to said inner surface through brick work and, particularly in modern buildings, through a wall cavity separating an inner and an outer wall.

The length of the rectangular liner will depend upon the thickness of the walls and the cavity spacing and, typically, may range from anything from six inches to twelve inches. The ventilation devices are required to, firstly, darken the ventilation opening or hole such that said hole does not allow light to pass from the outside surface to the inside surface and vice versa.

Thus, although the hole allows air to enter the inside of the building, viewed from the inside, the hole is effectively dark, in that it does not allow light to penetrate.

In addition to preventing light entering the opening, the device provides a passage through which air may be sucked in from the inside, in order to provide air to combustion appliances. However, although outside air may be sucked from the inside, the device is arranged such as to significantly reduce the quantity of air which may be blown in from the outside.

The ventilation device comprises a plurality ofabutting collars 15 each of which includes a centrally extending baffle 16 and a pair of edge baffles 17, 18.

Although the flow ofair through the device follows a meandering path between the extending baffles, the overall effect is to produce a direction of flow which is substantially perpendicular to the outer and inner wall surfaces.

Thus, the centrally extending baffles and the edge baffles may be considered as being mutually displaced in the ventilation direction, illustrated by arrow 19. However, when viewing along the direction of arrow 19, a centrally extending baffle 16 overlaps the edge baffles 17, 18 in the plane normal to said direction.

A ventilation opening will tend to be provided between two structural walls, having an air cavity therebetween. It is not desirable for the internal wall nor the external wall to be given access to the internal cavity, therefore an external orifice is connected to an internal orifice via a rectangular liner.

The ventilation device is assembled within the liner and consists of a telescopic spigot 21. The spigot includes a mounting flange 22 which abuts against an inner wall, allowing a grille to be secured thereon, by means of co-operating screws. Baffle collars are then inserted within the spigot from the inside, facilitating retrofitting or adjustment. The external orifice may be covered by an airbrick, thereby preventing access for large objects such as animals etc. It is not necessary to provide a external cowl which may be susceptible to accidental or vandal damage.

Referring to Figure 3, each baffling collar 31 provides a closed rectangular surface which abutts against the inside of the rectangular spigot 21. In the embodiment shown, a centrally extending baffle 32 is provided on one side of each collar while edge baffles are provided on the opposing side of said collar. The number of collars inserted within a rectangular liner is variable, dependant upon the degree of baffling required for a particular situation. Increasing the number of baffles present within the liner will reduce the flow of air through the opening due to external wind pressure. However, it will be appreciated that baffles will also increase the pressure drop across the ventilation opening, thereby creating a higher resistance to the ventilation process.For any arrangement of baffles, the resulting effective free area may be calculated and the number of baffles present within the rectangular liner adjusted accordingly. However, it should be appreciated that modifications to the device are easily effected such that additional air may be made available if the ventilation demand increases.

In the preferred embodiment, baffling collars are inserted within the rectangular spigot in an alternating fashion, such that a first collar has it's edge baffles directed towards the inside with it's centrally extending baffle directed towards the outside. Thereaffer, the next baffling collar is inserted in the reverse direction, such that it's centrally extended baffle is directed towards the inside with it's edge baffles directed towards the outside. In this way, baffles mutually abutt which in turn improves the rigidity of the system.

Ifrequired, mutually abutting baffles may be connected by connecting devices or adhesives.

The assembly of baffling collars shown in Figure 3 is also in Figure 4, with said collars abutted together ready for insertion within the rectangular liner. The baffles are configured such that they will achieve the effect of restricting iightfrom the outside and restricting externally generated draughts and noise, while at the same time minimising the resistance to desired ventilation currents. Each baffling collar is approximately one inch in depth, therefore a sufficient length of spigot may be provided for substantially any depth of wall opening. As previous stated, it is also possible to easily remove baffles or adjust the baffling arrangement, when increased or reduced demands are made on the ventilation requirement.

The preferred embodiment has been described with reference to an opening of substantially two house bricks in size, although it will be appreciated that the system may be extended for use in smaller or larger openings. The device significantly reduces the effects of externally generated air currents and noise, while preventing light entering from outside and, at the same time, optimising it's performance with respect to required ventilation. It is easily maintained and, as required, adjusted.

The device may be added to existing ventilation openings or, alternatively, a new opening may be created. The device is particularly suitable for cavity walls, wherein a substantially rectangular liner is inserted within the openings of both sub walls so as to define a ventilation passage between the inside of a room and an external environment.

Thus, an opening of specified size, usually the size of two house bricks, is established in both sub walls of the cavity wall. The substantially rectangular liner is then inserted within the openings of both sub walls, so as to bridge the cavity between said sub walls and so as to lie flush with the internal surface of the inner sub wall and the external surface ofthe outer sub wall. The spigot is located within the liner and collars, having centrally extending baffles and pairs of edge baffles, are inserted within the spigot.

Thus, the centrally extending baffles are displaced from said edge baffles in the ventilation direction but overlap the edge baffles in the plane normal to said direction.

It will be appreciated that the baffling effect may be increased or reduced by increasing or reducing the number of collars inserted within the spigot. Thus, in this way, the effect of external draughts may be reduced by increasing the number of baffles or, alternatively, the available free air from the ventilator may be increased by reducing the number of baffles present within the liner.

The length of the liner may be adjusted so as to allow the device to be employed in cavity walls of any currently employed width. The collars are relatively thin, therefore the baffles may be used even with relatively narrow cavity walls.

Claims (20)

1. A ventilation device for a ventilation opening, wherein said opening is defined by a substantially rectangular lining means, comprising a centrally extending baffle positionable within said lining means so as to be substantially normal to the ventilation direction, and a pair of edge baffles positionable within said lining means so as to be substantially normal to the ventilation direction, wherein said centrally extending baffle is displaced from said edge baffles in the ventilation direction but overlaps said edge baffles in the plane normal to said direction.

2. A device according to claim 1, wherein said cavity is substantially the size of two house brick spacings.

3. A device according to claim 2, wherein said cavity is substantially nine inches across and six inches down.

4. A device according to any of claims 1 to 3, wherein a grille is connectable over an indoor opening of a spigot forming part of said lining means.

5. A device according to any preceding claim, wherein an airbrick is positionable against an outside opening of said lining means.

6. A device according to any preceding claim, wherein said baffles are mounted on collars insertable within said lining means.

7. A device according to claim 6, wherein each collar supports a central baffle and a pair of edge baffles.

8. A device according to claim 7 wherein two of said collars are inserted within said lining means, with central baffles mutually abutting or with edge baffles mutually abutting.

9. A device according to claim 7, wherein a plurality ofcollars are inserted within the liner, wherein internal central baffles mutually abutt and internal edge baffles mutually abutt.

10. A method of ventilating a room via an outside cavity wall, comprising steps of establishing an opening of specified size in both sub-walls of said cavity wall; positioning substantially rectangular lining means within said opening, positioning a centrally extending baffle within said lining means so as to be substantially normal to the ventilation direction; and positioning a pair of edge baffles within said lining means so as to be substantially normal to the ventilation direction, wherein said centrally extending baffle is displaced from said edge baffle in the ventilation direction but overlaps said edge baffle in the plane normal to said direction.

11. A method according to claim 10, wherein an opening is established having a size of substantially two house brick spacings.

12. A method according to claim 11, wherein said opening is substantially nine inches across and six inches down.

13. A method according to any of claims 10 to 12, wherein a grille is connected over an indoor opening of a spigot forming part of said lining means.

14. A method according to any of claims 10 to 13, wherein an airbrick is positioned against an outside opening of said lining means.

15. A method according to any of claims 10 to 14, wherein said baffles are mounted on collars and said collars are inserted within said lining means.

16. A method according to claim 15, wherein each collar supports a central baffle and a pair of edge baffles.

17. A method according to claim 16, wherein two ofsaid collars are inserted within said liner, with central baffles mutually abutting or with edge baffles mutually abutting.

18. A device according to claim 16, wherein a plurality of collars are inserted within said lining means, with internal central baffles mutually abutting and internal edge baffles mutually abutting.

19. A ventilation device substantially as herein described with reference to the accompanying Figures.

20. A method of ventilating a room via an outside cavity wall, substantially as herein described with reference to the accompanying Figures.