GB2320563A

GB2320563A - Ventilator

Info

Publication number: GB2320563A
Application number: GB9626461A
Authority: GB
Inventors: Richard Arthur Waters; Philip John Jones; Arthur Stoney
Original assignee: Titon Hardware Ltd
Current assignee: Titon Hardware Ltd
Priority date: 1996-12-20
Filing date: 1996-12-20
Publication date: 1998-06-24
Anticipated expiration: 2016-12-20
Also published as: GB2320563B; GB9626461D0

Abstract

A ventilator canopy (10) is adapted for location adjacent a slot (80) through a window sash 70. The ventilator includes a cambered wing 30. One edge of the wing is hinged to the body of the canopy. The flap is biased to an open position by a flexible hinge 60 and/or a spring 100. In the open position, air may flow into the canopy, past the other edge of the wing (which may include an air-spoiling toe 120) and into the ventilation slot. As the wind speed increases, the flap moves towards the slot to restrict the air flow through the ventilator. A bi-metallic strip 110 may be provided to move the flap and likewise restrict ventilation in very cold weather. The wing may incorporate apertures 90, on either side of the articulation 220 formed part-way between the hinge 60 and toe (120).

Description

VENTILATOR This invention relates to a ventilator, such as to a self-adjusting ventilator.

In rooms with sealed windows, it is desirable to provide ventilation without having to open the window or door. This type of ventilation is now usually referred to as "secondary ventilation.

Secondary ventilation is often achieved by the insertion of a slot ventilator into the sash or frame of a window or into a door or doorframe. Usually, a manually operable closure or grille is provided at the inside end of the slot in the sash (i.e. in the room), the outside end of this slot normally having a canopy in the form of a lip extending outwardly and downwardly from the upper edge of the slot, to resist the ingression of rain and other airborne matter.

A number of different opening and closing mechanisms have been proposed to adjust the airflow through the resultant ventilation passage. A problem though is that the area of the ventilator through which air may flow is usually substantially fixed. Thus, any significant change in the rate of flow of air at the external surface of the ventilator causes the consequent change in the flow of air into the room. This means that sudden external gusts of wind may cause unwanted draughts to appear inside the room. Self-adjusting ventilators have been proposed but these are sensitive and tend to close the ventilation passage fully in medium wind conditions.

This is undesirable since the room suffers from reduced ventilation. One type of self-adjusting ventilator includes a flap one edge of which slides along a guide surface during adjustment of the ventilation passage.

This is undesirable since, over time, dirt or other matter may build up inside the ventilator with the result that the friction of the sliding movement is altered, thus undesirably altering the self-adjusting nature of the ventilator. Also, as a result of the sliding engagement, the flap is susceptible to freezing up in severely cold moist weather.

The present invention aims to alleviate the problems of the prior art.

According to the present invention there is provided a ventilator comprising an elongate housing and a movable flap located in the housing, the flap having a cambered cross section and a distal edge around which air flow may pass, in an open position of the flap, from one side of the flap to the other1 the flap being adapted to move from the open position, in response to a pressure differential across the ventilator, to a restriction position in which air flow around the distal edge is restricted or prevented.

In use, the ventilator may be located adjacent a slot passing through a building structure such as a window sash. When there is very little or no wind, a substantially unobstructed path is provided to the air flow through the slot. At higher wind speeds, the flap preferably moves towards the slot to obstruct the passage of air partially but not totally, thus minimising draughts but maintaining a level of ventilation. When the wind becomes very strong, air flow around the distal edge of the flap is preferably cut off entirely.

Preferably, the convex surface of the flap faces an inlet to the housing. Using a cambered flap, particularly arranged in this manner (convex surface facing the inlet), medium strength winds are able to maintain the flap effectively in an intermediate position where it permits an amount of air, albeit restricted, to flow around the distal edge.

Preferably, the flap is of substantially constant sectional width between the distal edge and an opposite edge thereof. In a preferred embodiment, the cross section of the flap is substantially semi-circular.

Preferably, the distal edge of the flap includes a protruding toe adapted to spoil air flow around the distal edge. This assists in moving the flap from the open position to the restricted position at medium wind speeds. The distal edge is preferably adapted to move along a predetermined path between the open and restricted positions. The toe may comprise a portion of the flap which points along or against the predetermined path.

The flap is preferably connected to the housing by attachment means located at an edge of the flap opposite the distal edge. In this case, the attachment means may comprise a hinge connecting the flap to the housing.

This provides a simple structure which does not as a necessity rely on friction to determine the selfadjusting nature of the flap.

Preferably, the ventilator includes biasing means for biasing the flap to the open position. The biasing means may include spring means adapted to bias the flap to the open position. When the ventilator includes attachment means in the form of a hinge connecting the flap to the housing, the hinge may be of resilient material, such as plastics material, being arranged to bias the flap to the open position.

In one embodiment, the flap has an air flow aperture formed therethrough from one side thereof to the other.

This may permit a certain amount of air to pass through the ventilator even when high wind speeds are present.

Preferably, a series of said holes are provided. Each one preferably has the form of an elongate slot.

The flap may include an articulation part-way between the distal edge and the opposite edge thereof.

The articulation may comprise a reduced thickness portion of the flap. When an air flow aperture is formed through the flap as discussed above, this may be located between the distal edge and the articulation. The articulation may in a fully restricted position of the ventilator, seal against a part of the ventilator or a structure to which the ventilator is mounted to prevent air flow through the ventilator. The flap may include a backing strip located at the articulation for effecting a substantially air tight seal in the fully restricted position and/or for restricting articulated movement of flap portions on either side of the articulation in one rotational direction relative to each other. The articulation is preferably closer to the distal edge than to the opposite edge of the flap. The articulation may be located on the flap about one third of the way from the distal edge to the opposite edge.

The flap may be provided in elongate form, the longitudinal direction thereof being substantially aligned with that of the housing. In this case, a plurality of elongate through slots may be provided in a series along the length of the flap.

Preferably, the ventilator includes a temperature sensitive regulator which is adapted to move the flap towards the restriction position in response to a change in temperature. Preferably, the regulator is adapted to move the flap towards the restriction position in response to reducing ambient temperature. This avoids the flow of relatively large amounts of air through the slot on a cold day, even when the wind speed is low. The regulator preferably comprises a by-metallic strip.

In one embodiment, the ventilator includes a movement stop which is adapted to engage the flap when the flap is in the open position.

In a most preferred embodiment, the housing comprises a weather canopy which is adapted for location on an external surface of a building structure adjacent a ventilation slot therethrough.

The housing may have a cambered cross section. The housing may include a gutter located at one edge thereof.

The present invention can be put into practice in various ways, and two specific embodiments will now be described, by way of example, with reference to the accompanying drawings in which : Figure 1 shows a perspective view, partly cut away, of a preferred ventilator assembly embodying the present invention; Figure 2 shows a section along the line AA of the ventilator assembly of figure 1 located in position with a window section; Figure 3 shows a schematic end view of a second preferred ventilator assembly embodying the present invention; and Figure 4 is a schematic projection of part of a flap of the ventilator assembly of Figure 3, viewed from below.

The ventilator canopy as indicated generally at 10 in Figure 1 may be seen to be cowl-shaped, and has a front wall 20 which defines an interior which, in essence, is a quadrant of a cylinder. As may be seen more clearly in Figure 2, the canopy 10 is mounted onto the sash of a window 70, adjacent to a precut slot 80 which passes through the window sash to the interior of the window (not shown). The interior end of the slot may be covered by a grille or the like; such grilles are well known in the art, and will not be discussed further.

It may thus be seen that the canopy 10 protects the slot 80 whilst providing a path for air towards the interior of the window through the canopy's lower opening and the slot 80 in the sash 70.

Attached to the top of the interior of the canopy is a hinge 60. This may be constructed from a flexible plastics material to allow substantial elastic deformation as is described further below. It will, of course, be appreciated that the hinge may be attached to any suitable location within the ventilator assembly, for example to the upper edge of the slot 80 in the sash.

One end of the hinge 60 is attached to a flap or wing 30, which is an elongate element arranged along the length of the canopy and is cambered in section. As may be seen in Figure 2, the wing is biased into an "open" position (denoted 'A') by the flexible hinge 60, when there is little or no wind blowing. Depending on the elasticity of the material from which the hinge 60 is formed, a further clockwise torque on the wing 30 may be provided by a spring 100.

A stop 50 holds the wing away from the side of the canopy 10 so that, even when there is little or no wind, there is at least some barrier to air flow from outside the canopy to the interior of the slot 80 in the window sash 70.

An increase in external wind speed produces an additional force on the lower end of the wing - that is, the end of the wing which is not attached to the hinge.

An anticlockwise torque about the hinge 60 is thereby produced which causes the wing to move off the stop 50 towards the window sash 70. The end of the wing 30 distal from the hinge may further be fitted or preformed with a toe 120, whose purpose is to assist in providing an adequate torque about the hinge 60 by spoiling the air flow around the distal end. For example, at intermediate wind speeds it may be desirable for the wing to lie in one of a plurality of intermediate restriction positions such as that denoted 'B' in Figure 2. It will readily be seen that the path for air from outside the canopy 10 around the lower end of the wing and into the slot 80 is thereby diminished. It is noted that the convex side of the wing 30 faces an inlet 130 to the canopy. This is a particularly advantageous feature since the ability of the flap to move to an intermediate restriction position appropriate to the incident wind speed is substantially improved. It should be noted that the flap is adapted to move gradually towards the slot 80 with increasing pressure differential across the ventilator.

When the wind speed increases still further, the wing is subjected to still higher torque about the hinge 60. The end of the wing, once more under the assistance of the toe 120 if necessary, is finally urged into abutment with the window sash 70 as shown at position 'C' in Figure 2. At this point, the path for air from outside of the canopy around the lower end of the wing to the slot 80 is closed.

In order to allow at least some airflow, even when the wing is in the closed position denoted 'C' in Figure 2, the upper portion of the wing 30 adjacent the hinge 60 is provided with rectangular slots 90. A further set of these slots 90 may be cut or formed in the end of the wing distal from the hinge, as may be seen in Figure 1.

During periods of cold weather, it may be undesirable to have a substantially unimpeded flow of air to the slot 80 when the wind speed is low and the wing is biased into its open position 'A'. A bimetallic strip 110, formed of suitable metals or alloys, is therefore bonded to the upper side of the hinge 60. When the ambient temperature at the canopy drops below a certain value, the bimetallic strip bends downwards due to the differential thermal contraction of the two materials from which it is formed. The wing 30 is thereby forced away from the stop 50 and toward the slot 80. The bimetallic strip is adapted, in the present embodiment, to force the wing into the closed position C' when the temperature drops below OOC; the temperature at which the wing 30 abuts the sash 70 may, of course, be altered by suitable choice of bimetallic strip 110. Furthermore, the bimetallic strip 110 may equally well be bonded to the underside of the hinge 60.

Figure 3 shows a second preferred ventilator 200 which has a cambered canopy 202. The canopy has a fixing flange 204 at an upper edge thereof and a gutter portion 206 at a lower edge thereof.

The fixing flange is secured to an upper surface 207 of a sash 208 of a window assembly, above a ventilation slot 210 formed through the sash 208. Once installed on a building (not shown), the canopy 202 could conveniently form the exterior weather canopy of a slot ventilation assembly.

A movable ventilation flap 212 is located inside the canopy 202 and is mounted thereto by a mounting flange 214 of the flap 212 which terminates at a primary hinge 216. An end stop 218 is located on the canopy 202 and sets the open position shown in Figure 3 of the flap 212.

The flap includes an articulation 220 which is located approximately two thirds (such as somewhere between 55 and 75%) of the way from the primary hinge 216 to a distal edge 222 of the flap 212. The articulation 220 permits a lower portion 224 of the flap 212 to rotate, as viewed in Figure 3, anti clockwise with respect to an upper portion 226 of the flap 212. At the articulation, the flap is provided with a backing sheet 228 which serves to prevent the lower portion 224 from rotating clockwise relative to the upper portion 226, as viewed in Figure 3. The backing sheet 228 also serves as a seal, as will be described below.

The flap 212 includes a protruding toe 230 which is located at the distal edge 222.

As the strength of incoming air through the ventilator 200 increases with an increasing pressure differential across the ventilator 200, , the flap 212 pivots about the primary hinge 216 towards a lower surface 232 of the sash 208. It will be noted that the toe 230 protrudes from the flap 210 in the direction in which the flap 212 moves towards the lower surface 232 of the sash 208. In this respect, it will be noted that the toe is different from the toe 120 shown in Figure 2 which protrudes from the flap or wing 30 in a direction substantially opposite to that in which the flap 30 moves as it approaches the closed position "C".

As the pressure difference across the ventilator 200 increases to a certain level, the toe 230 comes into contact with the lower surface 232 of the sash 208. As the pressure differential across the ventilator 200 progressively increases from that point, the flap 212 folds progressively at the articulation 220, until the backing sheet 228 comes into contact with the lower surface 232 of the sash 208. The orientation of the flap 212 at this point is shown in dotted lines in Figure 3.

The backing sheet acts as a seal against the lower surface 232 of the sash 208.

As shown in Figure 4, the flap 212 includes a series of trapezium-shaped cutouts 234 formed along its length, adjacent the distal edge 222. These cutouts 234 are located between the articulation 220 and the distal edge 222. Therefore, in the fully restricted position shown in dotted lines in Figure 3, the cutouts 234 do not permit airflow through the ventilator 200, since they are below the backing strip 228.

The articulation 220 and primary hinge 216 may both be constituted by local weakenings in the flap 212, such as reduced thickness portions thereof. The articulation 220 and hinge 216 nevertheless are resilient and bias the flap 212 towards the position and orientation which it has shown in full lines in Figure 3. The size of the cutouts 234 may be selected in conjunction with the level of resilience of the hinge 216, in order to provide a proper level of restriction of ventilation for any pressure differential across the ventilator 200. If a minimum level of ventilation is required, the flap 212 could be provided with ventilation apertures therein, located between the hinge 216 and the articulation 220.

In the fully restricted position of the ventilator shown in dotted lines in Figure 3, it will be appreciated that such apertures would be above the backing strip 228 and would therefore permit some ventilation through the slot 210. The size of such apertures and the cutouts 234, as well as the resilience of the hinge 216 and articulation 220 may be varied to provide the desired flow rate characteristics for any particular climate.

Furthermore, the ventilator 200 may incorporate a temperature sensitive actuator, such as one similar to the bi-metallic strip 110 shown in Figure 2. The ventilator 200 may optionally incorporate a return spring, similar to the spring 100 shown in Figure 2.

Whereas the present embodiments describe the use of the ventilator canopy adjacent a ventilation slot through a window sash, the canopy may also be used adjacent other types of ventilation slot, such as a slot through a door or door frame, or a window frame.

Claims

1. A ventilator comprising an elongate housing and a movable flap located in the housing, the flap having a cambered cross section and a distal edge around which air may flow, in an open position of the flap, from one side of the flap to the other, the flap being adapted to move from the open position, in response to a pressure differential across the ventilator, to a restriction position in which air flow around the distal edge is restricted or prevented.

2. A ventilator as claimed in claim 1 in which the distal edge includes a protruding toe adapted to spoil air flow around the distal edge.

3. A ventilator as claimed in claim 1 or claim 2 in which the flap is connected to the housing by attachment means located at an edge of the flap opposite the distal edge.

4. A ventilator as claimed in claim 3 in which the attachment means comprises a hinge connecting the flap to the housing.

5. A ventilator as claimed in any one of the preceding claims which includes biassing means for biassing the flap to the open position.

6. A ventilator as claimed in claim 5 when dependent upon claim 4 in which the hinge is of resilient material and is arranged to bias the flap to the open position.

7. A ventilator as claimed in claim 5 or claim 6 in which the biassing means includes spring means adapted to bias the flap to the open position.

8. A ventilator as claimed in any one of the preceding claims in which the flap includes an air flow aperture formed therethrough from one side thereof to the other.

9. A ventilator as claimed in any one of the preceding claims in which the flap includes an articulation partway between the distal edge and the opposite edge thereof, preferably closer to the distal edge than to the opposite edge.

10. A ventilator as claimed in claim 9 when dependent upon claim 8 in which the air flow aperture is located between the articulation and the distal edge.

11. A ventilator as claimed in claim 9 or claim 10 in which the articulation is adapted to seal, in a fully restricted position of the ventilator, against a part of the ventilator or part of a structure to which the ventilator is mounted to prevent air flow through the ventilator.

12. A ventilator as claimed in any one of the preceding claims which includes a temperature sensitive regulator which is adapted to move the flap towards the restriction position in response to a change in temperature.

13. A ventilator as claimed in any one of the preceding claims which includes a movement stop which the flap is adapted to engage in the open position.

14. A ventilator as claimed in any one of the preceding claims in which the housing comprises a weather canopy.

15. A ventilator as claimed in claim 14 in which the canopy is elongate and has a cambered transverse cross section.

16. A ventilator substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.

17. A ventilator substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.