GB2292454A

GB2292454A - Temperature-responsive slot ventilator

Info

Publication number: GB2292454A
Application number: GB9416755A
Authority: GB
Inventors: Arthur Stoney; Richard Arthur Waters; Philip John Jones
Original assignee: Titon Hardware Ltd
Current assignee: Titon Hardware Ltd
Priority date: 1994-08-18
Filing date: 1994-08-18
Publication date: 1996-02-21
Anticipated expiration: 2014-08-18
Also published as: GB2292454B; GB9416755D0

Abstract

A ventilator, secured to the exterior side of a ventilator slot extending between the interior and exterior of a building, has a housing with an inlet and an outlet and a bowed wall (21) therebetween. A normally straight baffle strip 26' is attached to the centre of the wall (21) and there are non-aligned apertures (25), (28) in the wall and baffle respectively. When the pressure differential between the inlet and outlet is low and the air temperature is warm, the baffle 26' is well-spaced from the wall, but when the air temperature becomes very cold, bimetallic strips 40' cause the baffle 26' to bow towards the wall to close the flow path through the apertures. The bimetallic strips may be progressively acting or snap type. The baffle 26' is also pressure responsive, as in the prior art Fig. 4 (not shown), responding to increased pressure differential to bow towards the wall and progressively restrict the apertures. <IMAGE>

Description

VENTILATOR This invention relates to ventilators, more particularly but not exclusively for use in rooms with sealed windows and/or double glazing where it is desirable to provide ventilation without having to open the window.

According to the present invention there is provided a ventilator for location adjacent a ventilation slot which extends between a room and space exterior to the room, the ventilator including a regulator comprising an elongate generally flat wall, a baffle element, one of the wall and baffle element having an air flow aperture formed therethrough, and restrictor means which is adapted to move the baffle element, in response to a temperature change, towards the wall to cause obturation of the aperture to restrict air flow through the ventilator. Preferably, the restrictor means is adapted to move the baffle element in dependence upon the temperature of air flowing through the ventilator.

The restrictor means may comprise an element whose shape changes with changes in temperature. Preferably, the restrictor means comprises one or more bi-metallic elements, preferably in the form of generally flat strips. In this case, the strip or strips may be located extending generally adjacent the baffle element. This has the advantage that the strip or strips take up very little space.

In a preferred embodiment, the ventilator comprises a housing with an elongate inlet thereto, the aperture being formed in the wall to provide an outlet from the interior of the housing so as to provide a flow passage for air through the interior of the housing from the inlet to the outlet. The restrictor means may be located between the inlet and the outlet. Thus, when the restrictor means comprises one or more bi-metallic strips, these may be located inside the housing. Thus the ventilator may be in the form of a self-contained unit which does not require an external input for moving the baffle element to restrict air flow as desired.

The housing may include a weather canopy. Thus, the ventilator may be located exterior to a building, adjacent to a ventilator slot which extends into the building, and rain and other undesirable precipitation is prevented from entering the ventilator.

Preferably, the baffle element is located between the inlet and outlet of the housing.

Preferably, the baffle element comprises an elongate flexible strip. In this case, the restrictor means may be adapted to flex the strip towards the wall to cause the obturation of the aperture. This has the advantage that no linkage mechanism for the baffle element (such as pivots or the like which would be required with a rigid element and could jam with age) is required for movement of the strip.

In a preferred embodiment, the wall includes a row of apertures, the baffle element comprises an elongate strip extending generally parallel to the wall and movable towards the apertures for obturating them. Preferably, the baffle element has a second row of apertures which are at least partially out of register with the apertures in the wall when the strip is adjacent to the wall. The apertures in either or both of the wall and baffle element may be in the shape of rectangles.

Preferably, a bias is associated with the baffle element, tending to bias the baffle element away from the wall.

The bias may be provided by one or more springs but, preferably, the baffle element is self-biassing, comprising or incorporating resilient material.

When the baffle element is elongate, such as in the form of the strip mentioned above, the baffle element may be secured to the wall in contact therewith at a point along its length, diverting from the wall away from the point of anchorage. Abutment means may be provided on the baffle element or the wall or both to prevent face to face contact between the baffle element and wall in order to ensure that a limited degree of ventilation will always be possible and to prevent the baffle element from undesirably adhering to the wall.

Preferably, the restrictor means is adapted to cause restriction of air flow through the ventilator in response to a drop in temperature. Restriction may begin to occur as temperature (of air flowing through or in the vicinity of the ventilator and, accordingly, also of the restrictor means (e.g. a bi-metallic element)) drops below a temperature of about plus 0 to minus 15"C.

Restriction may begin to occur as temperature drops through about 0 C. The restrictor means may be tuneable so that it is possible to select the temperature at which restriction begins to occur. Preferably, the restrictor means is adapted to provide a progressive restriction of air flow as temperature falls progressively below a predetermined value; nevertheless, rapid restriction could be provided, as an alternative, by using a rapidacting restrictor means, such as a snap type bi-metallic strip.

In a preferred embodiment, the baffle element is movable towards the wall in response to a pressure differential across the ventilator. Movement of the baffle element towards the wall may be progressive, in response to a progressive increasing differential across the ventilator. Thus a ventilator may be provided which in relatively warm and calm weather conditions permits maximum ventilation, but which prevents draughts flowing into the room in windy conditions, and which also restricts ventilation when the outside air temperature falls below a particular value.

In a preferred construction, the ventilator may be secured to the exterior side of a ventilator slot extending between the interior and exterior of a building. The ventilator has a body with an inlet and an outlet and a bowed wall therebetween. A normally straight baffle strip is attached to the centre of the wall and there are non-aligned apertures in the wall and baffle respectively. When the pressure differential between the inlet and outlet is low and the air temperature is warm, the baffle is well-spaced from the wall, but as the pressure differential increases, the baffle is bowed progressively towards the wall to close the flow path through the apertures. Bi-metallic strips ensure that the baffle is also bowed towards the wall when the air temperature becomes very cold.

The present invention may be carried out in various ways and one ventilator in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a partial rear elevation of a prior art ventilator; Figure 2 is an end elevation of the ventilator shown in Figure 1; Figure 3 is a cross section of the ventilator on the line 111-111 in Figure 1; Figure 4 is a partial horizontal longitudinal section on the line IV-IV in Figure 1.

Figure 5 is a cross section similar to Figure 3 on the line V-V in Figure 4; Figure 6 is a diagrammatic horizontal longitudinal section similar to Figure 4 but to a smaller scale and showing the whole of the ventilator; Figure 7 is a partial isometric view of a preferred ventilator in accordance with the invention;.

Figure 8 is a cross section of the ventilator of Figure 7; Figure 9 is an elevation of a transit clip for the ventilator of Figure 7; and Figure 10 is a partial bottom plan view of the ventilator of Figure 7.

Referring to Figures 1 and 3, a prior art ventilator comprises essentially an elongate box which is in the form of a tubular housing made from three components 1, 2 and 3, the first constituting the body of a weather canopy and providing the upper and front walls 4 and 5 of the canopy, the second providing the rear wall of the ventilator and the third constituting an insect screen 7 which forms the bottom wall of the box. The ends of the tubular housing are closed by moulded end pieces 8 and 9 having openings 11 for screws by which the ventilator may be secured to the surface (not shown) to which it is attached.

The ventilator canopy has a generally downwardly facing open mouth which is closed by the insect screen 7, the longitudinal edges of the screen being retained in slots 13, 14 moulded in the lower edges of the walls 2 and 1 respectively. The rear wall of the ventilator is afforded by the second component 2 which is a complex moulding having a longitudinal wall 21 which is generally bow shaped in plan as can be seen in Figure 4. The longitudinal wall 21 is supported by upper and lower horizontal walls 22, 23 which are interconnected by vertical walls 24 to provide a coffered effect when viewed from the rear. The bowed longitudinal rear wall is formed with a series of rectangular apertures 25. A baffle 26 in the form of a flexible strip is secured by fastenings 27 to the central portion of the longitudinal wall.The baffle 26 is formed with a similar series of rectangular apertures 28 which, as can be seen from Figure 4, are generally out of register with the apertures 26 in the wall 21. In the unstressed condition of the strip 26 as shown in Figure 4, the strip is straight or flat but under the effects of differential pressure, the strip is able to deflect to the position 26a shown in Figure 4 by chain dotted lines where it is adjacent to the wall 21 but remains spaced a short distance therefrom by a stop 29.

The lower wall 23 incorporates a low pressure slot 31 which ensures a minimum amount of ventilation at all times.

Figures 1 and 4 show only one end portion of the complete ventilator; Figure 6 shows the complete ventilator in which the rear wall struvture 2 is combined with a similar structure 35 which is only of half the length, the two being placed end to end within a main body 1 which is of appropriate length.

The operation of the prior art ventilator is as follows: When there is a small differential pressure between the downwardly facing mouth of the canopy and a slot against which the ventilator is positioned, the baffle 26 will be in the condition shown in full lines in Figure 4. Air can flow into the ventilator through the insect screen, through the apertures 28 in the baffle 26, through the apertures 25 in the wall 21, and then into the slot. As the pressure differential increases, the end portions or wings of the baffle 26 will tend to move against the resilience of the baffle towards the wall 21 thus increasing the resistance to air flow.When the pressure differential reaches a certain level, the baffle 21 will engage the stop 29 at which stage the more central apertures 25 in the wall 21 will be substantially closed while a progressively greater but still small flow will be possible through the outer apertures. Due to the stop 29, the baffle 26 cannot engage flat against the wall 21 so that there will always remain a small flow path for air through the wall 21 to provide a degree of ventilation. The low pressure slot 31 is located near to the end portion of the baffle 26 so that, even when there is a relatively large pressure differential, a certain amount of air is able to pass through the slot 31 under the baffle 26 and through one or more of the outer apertures 25 through the wall 21.When the pressure differential falls again, the resilience of the baffle 26 will tend to move the end portions of the baffle away from the wall 21 thus progressively increasing the cross section of the flow path through the canopy and into the slot until the baffle 26 returns to its unstressed position.

In Figures 7 to 10, similar reference numerals, with the addition of a prime, are used to denote similar components to those of the ventilator in Figures 1 to 6.

Referring to Figures 7 and 8 a preferred ventilator in accordance with an embodiment of the invention includes first and second bi-metallic strips 40' which are located adjacent the baffle 26', extending generally parallel to it. The bi-metallic strips 40' are clamped between the baffle 26' and longitudinally aligned recesses 42' of an anchor plate 41' under the action of a fastening screw 27'. The bi-metallic strips are adapted to bend in the direction of the baffle when their temperature drops.

The bi-metallic strips 40' are preferably of the type which will bend progressively in the direction of the baffle 26' as their temperature drops. Alternatively, the bi-metallic strips 40 may be of the snap type, meaning that they will suddenly bend in the direction of the baffle 26' as their temperature drops below a predetermined value.

The ventilator includes a stop 29' which has a similar purpose to the stop 29 of the prior art ventilator.

Figure 9 shows a transit clip 45' which is insertable through one of the apertures 25' in the wall 21' to hold the baffle 26' in its flat condition so that it does not move undesirably during transit. Figure 10 shows two such transit clips 45' installed in the ventilator, each holding one portion of the baffle 26'. A peg 46' of each clip engages frictionally in an elongate channel 47' formed along the rear wall 2' of the ventilator. The transit clips 45' are removed during installation of the ventilator.

Operation of the ventilator shown in Figures 7 to 10 is similar to that of the prior art ventilator of Figures 1 to 6 in warm conditions. However, when the temperature of air flowing through or in the vicinity of the ventilator and, accordingly, also the temperature of the bi-metallic strips, drops below a certain level, the bimetallic strips 40', will bend in the direction of the baffle 26' to move it to the minimum ventilation position.This movement of the baffle 26' may begin to occur at about 0 C. If the bi-metallic strips are of the progressive type, they may progressively bend in the direction of the baffle 26' with decreasing air temperature, being calibrated so that they initiate movement of the baffle 26' towards the wall 21' at about O"C, completing movement of the baffle 26' to the minimum ventilation position (comparable to the position shown in chain dotted lines in Figure 4) at about minus 15 C.

Clearly, the operating range will vary according to the characteristics of the bi-metallic strip being used.

When the bi-metallic strips 40' warm up again, they bend away from the wall 21' , so that their influence on the baffle 26' is reduced, partially or totally, dependent upon their calibration and whether they are progressive or snap type strips.

Thus, it will be seen that the ventilator prevents undesirable strong or cold draughts through the slot to which it is mounted.

The rear wall structure 2' may, in other preferred ventilators, be combined with a similar structure of different length (e.g. half the length) with the two being placed end to end within a main body of appropriate length. Ventilators of other length may be provided, such as sones of one and a half, twice or three times the length of the ventilator shown in Figure 10.

Claims

1. A ventilator for location adjacent a ventilation slot which extends between a room and a space exterior to the room, the ventilator including a regulator comprising an elongate generally flat wall, a baffle element, one of the wall and baffle element having an air flow aperture formed therethrough, and restrictor means which is adapted to move the baffle element, in response to a temperature change, towards the wall to cause obduration of the aperture to restrict air flow through the ventilator.

2. A ventilator as claimed in Claim 1 in which the restrictor means comprises an element which is adapted to change its own shape in response to changes to temperature.

3. A ventilator as claimed in Claim 1 or Claim 2 in which the restrictor means comprises or includes a bimetallic strip.

4. A ventilator as claimed in any one of the preceding claims which comprises a housing with an elongate inlet thereto, the aperture being formed in the wall to provide an outlet from the interior of the housing so as to provide a flow passage path for air through the interior of the housing from the inlet to the outlet.

5. A ventilator as claimed in Claim 4 in which the restrictor means is located between the inlet and the outlet of the housing.

6. A ventilator as claimed in Claim 4 or Claim 5 in which the housing incorporates a weather canopy.

7. A ventilator as claimed in any one of the preceding claims which include means tending to bias the baffle element away from the wall.

8. A ventilator as claimed in any one of the preceding claims in which the baffle element comprises an elongate strip.

9. A ventilator as claimed in Claim 8 in which the strip is flexible and the restrictor is adapted to flex the strip towards the wall to obdurate the aperture.

10. A ventilator as claimed in claim 8 or claim 9 in which the wall includes a row of apertures, the elongate strip extends generally parallel to the wall and is movable towards the apertures for obdurating them, and the elongate strip includes a second row of apertures which are at least partially out of register with the apertures in the wall when the strip is located adjacent to the wall.

11. A ventilator as claimed in any one of claims 8 to 10 in which the elongate strip is anchored to the wall in contact therewith, and the strip, in one condition thereof, diverges from the wall away from the point of anchorage.

12. A ventilator as claimed in any one of the preceding claims in which the restrictor means is adapted to restrict air flow through the ventilator in dependence upon a drop in temperature.

13. A ventilator as claimed in Claim 12 in which the restrictor means is adapted to initiate restriction of air flow as temperature drops below about plus 0 to minus 15 C.

14. A ventilator as claimed in Claim 12 or Claim 13 in which the restrictor means is adapted progressively to restrict air flow as temperature falls progressively below a predetermined value.

15. A ventilator as claimed in any one of the preceding claims in which the baffle element is adapted to move towards the wall to restrict air flow through the ventilator in response to a pressure differential across the ventilator.

16. A ventilator as claimed in Claim 15 in which the baffle element is adapted to move progressively towards the wall with an increasing pressure differential.

17. A ventilator substantially as described herein with reference to Figures 7 to 10 of the accompanying drawings.