GB2583125A

GB2583125A - Ventilation device

Info

Publication number: GB2583125A
Application number: GB1905505.2A
Authority: GB
Inventors: J M Adams Darren
Original assignee: Titon Hardware Ltd
Current assignee: Titon Hardware Ltd
Priority date: 2019-04-18
Filing date: 2019-04-18
Publication date: 2020-10-21
Anticipated expiration: 2039-04-18
Also published as: GB201905505D0; EP3726156A1; GB2583125B

Abstract

The device 10 comprises a housing 12 having a passageway leading from a first port to a second port, one being arranged to act as an inlet 26 and the other as an outlet 28 and an airflow control member 14 is positioned at a first margin of the passageway between the inlet and outlet to provide free space between the airflow control member and an opposite second margin of the passageway. The airflow control member being configured to restrict the airflow in response to air pressure. The airflow control member may be arranged in response to a higher pressure at the inlet than the outlet to move so as to restrict flows towards the outlet from the inlet. Also disclosed is a ventilation device for regulating airflow through an opening wherein the airflow member controls air flow along the passageway in either direction, a pivot joint assembly comprising a pin and hole and an air port having an aperture and a member for restricting the aperture.

Description

VENTILATION DEVICE

FIELD

The invention relates to a ventilation device, and more particularly but not exclusively to a trickle ventilator, typically mounted to inside dwellings, usually in the frame for a window or door and forming part of the dwelling ventilation system.

BACKGROUND

GB 2432656A discloses a slot ventilator mounted on a window or door to be ventilated which requires manual adjustment by a user to adjust air flow through the device.

EP 0362913A1 discloses a self-regulating register in which the device vent shuts off above certain wind speeds and is unable to provide effective ventilation.

GB 2383124A discloses an air pressure operated ventilator device. In practice, the ventilator shuts off flow suddenly and provides notable mechanical noise during operation.

W02005003501 discloses a ventilation device for controlling ventilation through a passageway which requires two ventilators arranged in a 'back to back' configuration to provide airflow control in two directions.

The present disclosure seeks to alleviate, at least to a certain degree, the problems and/or address at least to a certain extent, the difficulties associated with the prior art. The present disclosure also seeks to provide a useful ventilation device.

SUMMARY

According to one aspect of the disclosure, there is provided a ventilation device for regulating airflow through an opening comprising a housing having a passageway leading from a first port to a second port, one being arranged to act as an inlet and the other as an outlet and an airflow control member, characterised in that the airflow control member, in a position thereof, is positioned at a first margin of the passageway between the inlet and the outlet to provide free space between the airflow control member and an opposite second margin of the passageway, the airflow control member being configured to move to restrict the airflow traveling past said member in response to air pressure. The first margin may be a lower margin. The second margin may be an upper margin.

According to another aspect of the disclosure, there is provided a ventilation device for regulating airflow through an opening comprising a housing having a passageway leading from a first port to a second port, one being arranged to act as an inlet and the other as in outlet and an airflow control member, characterised in that the airflow control member is configured to restrict the airflow travelling above said member in response to air pressure. The airflow control member may be arranged in response to a higher pressure at the inlet than the outlet to move so as to restrict flow towards the outlet from the inlet. The airflow control member may be arranged in response to a higher pressure at the outlet than the inlet to move so as to restrict airflow towards the inlet from the outlet.

A ventilation device for regulating airflow through an opening comprising a housing having a passageway leading between a first port and a second port and an airflow control member, characterised in that the airflow control member is configured to control air flow along the passageway in response to the air pressure difference across the device in either direction, whether the flow is from the first port to the second port and vice versa.

The housing may comprise a first part and second part to keep the number of parts to a minimum for simple assembly of the device. The structure of the housing may form a main circular cross section, which together with the inlet and the outlet provides an airflow pathway i.e. along the passageway through the device. The housing may further provide an internal cylindrical cavity for air to travel through relatively undisturbed. The housing may further comprise a cuboidal section providing fluid communication between the inlet and an internal cylindrical cavity within the circular cross section in order to provide the airflow a guided pathway into the internal cylindrical cavity.

The housing may also further comprise a cuboidal section providing fluid communication between the internal cylindrical cavity and the outlet in order to provide the airflow a guided pathway out of the internal cylindrical cavity.

The cuboidal sections may stem from opposite sides of the circular cross section of the housing such that the inlet and outlet are formed on opposite sides such that direction of airflow is not significantly altered when travelling through the device.

The airflow control member may comprise an elongate structure. The airflow control member may extend along within the housing circular cross section. The airflow control member may generally have a V-shaped section comprising of a front wall and a back wall which may optionally meet at an acutely angled apex such that the walls move together and rotationally offset from each other.

Each end of the airflow control member may comprise a curved edge adjoining the front and back walls, forming an end wall with a circular segment shape. This may have a dual benefit of providing structural rigidity and preventing air from flowing into the underside of the airflow control member from its ends.

A projected area of the curved edge along the length of the airflow control member may be equal or substantially equal to an area of the housing outlet in order to substantially completely restrict the outlet aperture when operating under high air pressures. The curvature or radius of the curve edge may be substantially equal to or slightly less than a curvature or radius of the internal cylindrical cavity of the housing so as to always provide a clearance during operational movement of the airflow control member. This also ensures that when the outlet is fully restricted, there is remaining a small gap to provide for a minimum airflow rate across the device. This may enable the device to operate in accordance with Building Regulations. The curved edge may optionally be a circular arc.

The position of the airflow control member may be self-adjustable in response to air pressure across the device and may optionally regulate flow at an exit from the circular section.

The device itself may be self-regulating in movement between a fully exposed outlet position and a substantively restricted outlet configuration such that no manual input is required to control the air flow through the device.

The airflow control member may be connected to the housing by a pin and hole joint or other type of hinge such that it is adapted to pivot about a central longitudinal axis of the housing.

This may therefore allow the control member to freely rotate within the housing without contacting any internal surface. Therefore the device will have minimal mechanical noise during operation.

The airflow control member may lie substantially completely below a pivot point thereof to allow for air to flow freely there past, optionally giving only a single air path to control by restriction.

Within the device, the outlet may be positioned substantially immediately after one of the walls of the airflow control member in its resting position resulting in minimal movement required by the control member during operation and minimal pressure difference to begin to restrict the vent.

The airflow control member may move in response to gradual changes in air pressure to gradually restrict the outlet, therefore continuously variably regulating the air flow rate across the device.

When the outlet area is substantially completely restricted, the airflow control member may be held in position by a balance of air pressure within the internal cylindrical cavity on the two walls of the airflow control member (the weight of the member also having an effect). As such the outlet remains restricted until the air pressure across the device is reduced. The weight of the air pressure member may play a part. The airflow control member may have a rest position to which it is biased by its own weight, a spring bias or both.

According to another aspect of the disclosure, a ventilator has a housing and an airflow control member arranged to be connected to the housing by a pivot joint assembly comprising a pin and a hole, wherein the pin has a diameter smaller than the hole. This pivot joint of a small diameter inside a larger diameter allows for minimal friction at the joint which is advantageous in optimising the sensitivity of the airflow control member in response to low air pressures, whilst making it easy to manufacture and assemble.

The depth of the hole may not exceed the length of the pin to ensure the pin is engaged with the end wall of the hole. The pin may be tapered or conical or may have another profile.

According to another aspect of the disclosure, a ventilation assembly is provided with an air port having an aperture and a member for restricting the aperture characterised by the aperture and/or member being shaped so that upon equal movements of the member relative to the aperture, unequal restrictions to the area for flow through the aperture are made.

This can ensure the airflow rate to be substantially constant regardless of the air pressure difference across the device. An aperture profile of the port may be selected to, for example, match the shape of the graphical relationship between Effective area and Air pressure so as to provide a substantially constant airflow rate over a range of pressure differentials across the ventilator. The aperture profile may be generally triangular with a straight base edge and two inwardly concave curved edges.

According to another aspect of the disclosure there is provided a window or door assembly or building assembly which includes the ventilation device in accordance with the first aspect of the disclosure. The ventilation device maybe used as part of a window or door assembly or building assembly, by mounting it at a ventilation slot extending from one side of the assembly to the other. The ventilation device as per the present disclosure can be used in conjunction with other devices such as but not limited to an external canopy, grille, or sound attenuating devices.

According to another aspect of the disclosure there is provided a building wall or roof assembly which includes the ventilation device in accordance with the first aspect of the disclosure.

According to another aspect of the disclosure there is provided a building facade assembly which includes the ventilation device in accordance with the first aspect the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be carried out in various ways. A preferred embodiment in accordance to the invention and modifications to it will now be described by way of example only in a non-limiting way with reference to the accompanying drawings, in which: Figure 1 shows a known prior art trickle ventilator device according to GB2432656A; Figure 2 is a perspective view of a preferred example of a ventilation device according to the invention; Figure 3 is an exploded view of the components of the device of Figure 2; Figure 4 shows a front view of the device with a second housing part removed; Figure 5 shows a perspective view of the device with a second housing part removed; Figure 6A is a schematic side elevation of the device in an open position; Figure 6B is a schematic side elevation of the device of in a partially closed position; and Figure 6C is a schematic side elevation of the device of in a closed position; Figure 7A to 7C is an equivalent representation of Fig. 6A to 6C for an alternative device with a modified outlet; Figure 8 shows a six sided perspective of the device of Figure 2; Figure 9 shows a graph of outlet airflow against air pressure for a 2527EA (Effective Area) device as per Figure 2, a known 2500EA ventilator device as per Figure 1 and a 4000EA sharp edge orifice; Figure 10 shows a graph of outlet airflow against air pressure for the ventilation device of different effective areas (EA); Figure 11 shows a graph of outlet air pressure against ventilator equivalent area calculated according to BS EN 13141-1:2004 for a 2527EA device as per Figure 2, a 1904EA device as per Figure 2, a 2500EA standard ventilator device as per Figure 1 and a 2500EA sharp edge orifice; Figure 12 shows a schematic end sectional views of a second preferred embodiment of the invention; Figure 13A shows a graph of the relationship between effective area and air pressure; Figure 13B shows an alternative preferred outlet aperture; Figure 13C shows an alternative preferred outlet; Figures 14 to 22 show alternative preferred embodiments of the airflow control member; Figure 23 shows the alternate device as per figure 7 operating under reverse flow configuration; and Figure 24 shows a graph for increasing and decreasing air pressures across the present device as per Figure 2, a known 2500EA vent as per Figure 1 and a pressure operated ventilation 20 device as per GB 2383124A.

DETAILED DESCRIPTION

Figure 1 shows a perspective view of a known trickle ventilator 1 according to GB2432656A. An air inlet is provided through a back wall and an air outlet is provided when a front member 2 is moved away from a mounting member 3. The device has an airflow ventilation path 4 which cannot be regulated without manually adjusting the position of the front member 2. The ventilator is not regulated in response to the air pressure across the device.

Figure 2 shows a perspective view of a first preferred embodiment of the invention. The ventilation device 10 comprises an elongate housing 12 and an airflow control member 14 (shown in figure 3). The device has a ventilation flow path 16 (Figure 6A) acting across a longitudinal axis of the device. The housing 12 generally has a circular cross section 18 running across its length, providing an internal cylindrical cavity 19 (shown in figure 6A) and two side walls 20a, 20b (Figure 2). From each laterally opposing side of the circular section 18 extends a generally cuboidal section 22 perpendicular to its longitudinal axis, running across the length of the housing. The height of each cuboidal section 22 is preferably less than the diameter of the circular section 18. The central longitudinal axis of each cuboidal section 22 is preferably offset vertically below the central longitudinal axis 18 of the circular section such that the majority of the cuboidal section is set below the centre of the circular section. Each cuboidal section 22 terminates perpendicular to the longitudinal axis of the circular section 18 providing a back wall 24a and a front wall 24b to the housing. The cuboidal sections 22 have a respective first port 25 (visible in Figure 8) and a second port 27 (Figure 2) comprising apertures in the housing as shown in Figure 2. The first port 25 may act as an inlet 26, preferably formed as an aperture in the back wall 24a and is an elongate rectangular area running across the housing providing, an inlet passageway 24a' (visible in Figure 6A) from the back wall to the internal cylindrical cavity 19. The second port 27 may act as an outlet 28, preferably formed as an aperture in the front wall 24b and is an elongate rectangular area running across the housing, providing an outlet passageway 24b' (visible in Figure 6A) from the front wall to the internal cylindrical cavity 19. The inlet and outlet passageways 24a', 24b' may be divided into sections along the length of the housing to provide structural integrity.

Figure 3 shows an exploded view of the components of the ventilation device 10. The housing 12 consists of first and second parts 30a, 30b split along the longitudinal axis of the circular section 18. The first part 30a forms half of circular section and the inlet passageway 24a' and a second part 30b forms the other half of the circular section and the outlet passageway 24U. The first part 30a has a groove slit 32 and the second part 30b has a complementary tongue 34 running across the perimetric edge where the two parts connect, allowing for easy alignment of the parts upon assembly of the device. In the embodiment of Figure 3, sides walls of the first part 30a provide a disc-shaped tab 35 adapted to be received by a complementary sized aperture 37 in the side wall of the second part 30b to provide a snap fit assembly connection between the housing parts. Other mechanical fastening methods may be provided in alternate embodiments.

The airflow control member 14 is an elongate structure spanning the length of the housing 12 with a generally V-shaped cross section, having a front 36 and back surface 38 (hidden in Figure 2) which meet at an acute angle. End walls of the control member 14 have the general shape of a circular segment characterised by a front edge 40, a back edge 42 edge and a curved edge 44 (Figure 3). The curved edge 44 is preferably circular and matches the curvature or radius of the internal cylindrical cavity 19 of the housing or is slightly less. The projected area of the curved edge 44 of the control member 14 preferably matches an area of the outlet passageway 28 just downstream of the control member 14. The apex of the front and back edges (40, 42) is extended vertically upwards providing an arch 46 at the end walls. A tapering pin 48 protruding from the arch outer surface 49 may be used in connecting the airflow control member 14 to the housing 12. The pin 48 is adapted to be received by an engagement hole 50 on an inner surface 51 of the first part of the housing 30a. The hole 50 is located at the centre point of the circular cross section 18 such that the control member 14 is able to pivot about the central longitudinal axis of the housing 12. The arch 46 is adapted to flex, allowing for easy pairing of the pin 48 and engagement hole 50 during assembly. A tapering pin 48 and engagement hole 50 are preferably provided on both ends of the control member 14 but other pivot joint mechanisms may be employed.

The airflow control member 14 is adapted to move in response to changes in air pressure.

Figures 4A and 4B show a section view of the pivot joint between the airflow control member 14 and the housing first part 30a. The tapering pin 48 preferably has a smaller radius at their area of engagement than the engagement hole 50 to provide a pivot joint with minimal friction. Minimising joint friction is advantageous in allowing the air control member 14 to move in response to small changes in air pressure (less than 1Pa).

Figure 5 shows the device with the second part of the housing 30b removed. The control member 14 preferably has an arcuate ribbing 52 running underneath the front 36 and back 38 surfaces allowing the control member 14 to be lightweight whilst retaining structural integrity. This is advantageous in allowing the air control member 14 to move in response to large changes in air pressure without torsional bending (more than 10Pa).

In use, the ventilator device 10 regulates the area of the outlet aperture in response to the air pressure difference across the device 10, therefore controlling the amount of air exiting the outlet 28. In Figure 6A, the device 10 is in a fully open position with the airflow control member resting freely under the influence of gravity. Air enters the internal cavity 19 through the inlet 26. At very low wind pressures, the force applied to the back surface 38 of the airflow control member is insufficient to cause it to pivot. The control member 14 remains unmoved and the air flows over the member exiting through the unrestricted outlet 28. A first margin 29 and a second margin 31 are provided at the point where the internal cavity 19 meets the outlet passageway 24b'. The internal cylindrical cavity 19 of the housing 12 allows the air to flow over the rotating member without restriction to allow the maximum possible air flow across the outlet at low wind pressures. The outlet passageway 24b' is positioned immediately after the control member 14 such that the front surface 36 of the member 14 is in line with the bottom edge 17 of the outlet passageway. This results in minimal movement required by the flow control member 14 to regulate the outlet. Figure 6B shows the position of the airflow control member at a higher wind pressure difference. As wind speed increases, the force applied to the back surface 38 of the control member 14 increases, and the control member 14 rotates about the pivot point 48, 50 to restrict the area of the outlet passageway 24b'. The air flowing over the control member 14 exits the partially restricted outlet passageway 24b'. The increase in wind pressures provides a higher air velocity, which when balanced against the reduced outlet area provides a generally consistent air flow rate. The control member 14 is situated a centre circular portion of the housing 18. This allows air to flow freely over the airflow control member 14, giving only a single air path to control by restriction. Above a certain threshold air pressure the airflow control member 14 rotates to the point where its curved region 44 covers the entire outlet passageway 24b' as shown in Figure 6C. The control member 14 at this point stops rotating as the air pressure around the member is balanced within the internal cylindrical cavity of the housing 19. The balance of air pressure around the control member (taking account of the weight of the member 14) results in the control member 14 being suspended in position.

In this embodiment, when the control member 14 is covering the outlet passageway 24b' at the full extent of its travel, there is a clearance gap 45 provided between the curved edge 44 of the control member 14 and an internal surface 47 of cylindrical cavity 19. This ensures a narrow pathway for airflow to travel around the control member 14 and exit the outlet 16 in order to maintain desired or minimum air flow across the device.

In another embodiment of the device 10 the housing 12 may further comprise an adjustable cover over the outlet to shut airflow through the device. A decrease in wind pressure reduces the force applied to airflow control member 14 and it rotates away from the outlet 36.

The control member 14 never comes in contact with any surface during rotation providing minimal mechanical noise during operation, without tapping, knocking noises.

To comply with UK building regulations, the ventilation performance of the device as per the invention is tested to the British Standard EN 13141-1 -Ventilation for Buildings. A notional ventilator size is calculated in relation to the area of a sharp edged circular orifice which would pass the same air flow rate at the same applied pressure difference. This is defined as an Equivalent Area (EA) in relation to the air ventilation flow rate at a reference pressure difference across the device. The equivalent area is given by - EA = k. q where -EA -equivalent area in mm2 q -volume flow rate at reference difference in 1/s k -co f f ecient given in Table 1 in mm2 / I/ s Table 1: Values of the coefficient k for several pressure differences AP (pa) k (mm2/1/s) 1 1271.9 2 899.4 4 636.0 8 449.7 402.2 284.5 In Figure 9, the graph compares the airflow rate versus air pressure for a 2527EA ventilation device as per the embodiment described above and a known 2500EA vent 1 as per Figure 1. Data for a 4000EA sharp edge orifice is also shown as a means to calibrate test equipment in accordance with BS EN13141-1. The results show the ventilation device begins to regulate the airflow immediately at low pressures of 10 Pa, 5Pa or lower as shown by the initial steeper curve when compared to the standard vent of a similar effective area. Above a threshold pressure value, in the region of 15 Pa to 30 Pa, say about 20 to 25 Pa, the airflow rate through the device is near constant regardless of the air pressure as shown by the near vertical region of its curve.

The results shown are for an embodiment dimensionally sized to meet building regulation requirements. The embodiment can be modified to achieve any airflow performance required as shown in the graph of Figure 10 where the airflow rate versus air pressure values for five ventilation devices are compared. Each device as per the present invention differs in dimensional size corresponding to an Effective Area of 2527EA, 1913EA, 1602EA, 1368EA and 1175EA respectively. The results shows every device to regulate airflow rate in response to changes in air pressure with the airflow rate being generally constant above a threshold pressure. In operation, this corresponds approximately to the point at which the airflow control member 14 has fully restricted the outlet 14 and the member is held in position by to the balance of air pressure as shown in Figure 6C. Hence, the device as per the present invention may be adapted to any size as desired.

Figure 11 shows a graph charting the change in notional effective area against air pressure for a 2527EA and a 1904EA device as per the invention and a known 2500EA vent as per Figure 1. The curve for the device shows a continuous decline in effective area as the air pressure rises. In operation, this corresponds to the gradual restriction of the outlet passageway by the airflow control 14 member as it rotates in response to increasing air pressures. In comparison the effective area of the standard vent of Figure 1 remains unchanged in response to rising air pressures. In operation, at high air pressures this device will not limit the air mass flow rate exiting its outlet, resulting in over ventilation.

An embodiment of the ventilation device as per the present invention may be installed in the sash or the frame of a window (or door or building). A window assembly 100 shown in Figure 12 includes glazing 102, a rectangular sash 104 and a rectangular frame 103. The frame 103 is mounted in an aperture 105 of a wall 106 of a building 107. The device 10 is mounted within a slot formed through upper frame member 109. A weather canopy 110 may be provided on an opposite, exterior side of the frame member 109. Other embodiments of the ventilation device may be built into the wall, facade or roof of any building.

For trickle ventilators left open there is a risk that the vent will leak droplets of water in raining conditions. The water tightness of a ventilator is tested by completing a water leakage test according to the British Standard EN 1027:2016. This provides devices with a class specification based on a comparison of the weathertightness in relation to specific test pressures. To meet any class the device must remain watertight for 5 minutes up to and at the test pressure set for that class. For the device 10 according to the invention, water tightness was tested under three scenarios -with the airflow control member 14 removed from the device 12, with the airflow control member 14 installed, and with the vent outlet 36 closed off. The test results for these scenarios are presented in Table 2, 3 and 4 respectively.

Table 2: Ventilation Device Watertightness test results -No airflow control member installed Pressure (Pa) Time (min) Result 0 15 Pass 5 Pass 5 Fail. Water droplets passed through the vent after 1 minute Table 3: Ventilation Device Watertightness test results -Airflow control member installed Pressure (Pa) Time (min) Result 0 15 Pass 5 Pass 5 Pass 5 Pass 5 Pass 250 5 Pass 300 5 Pass 450 5 Pass 600 5 Fail. Very strong airflow with small beads of water are passing through the outlet.

Table 4: Ventilation Device Watertightness test results -Vent closed Pressure (Pa) Time (min) Result 0 15 Pass 5 Pass 5 Pass 5 Pass 5 Pass 250 5 Pass 300 5 Pass 450 5 Pass 600 5 Passed all stages of test The table results show the installation of the airflow control member brings an improved performance of 450Pa over the 100Pa rating for an embodiment without the control member 14 installed. The 450Pa water tightness rating of the device 10 is a significant improvement over the standard trickle ventilator according to Figure 1 which achieves a rating of 100Pa in the open position. Hence the ventilation device 10 may successfully provide ventilation in adverse weather conditions compared to the prior art.

In another embodiment of the ventilator/device 10, the first port 25 and/or second port 27 may have multiple apertures shaped to control airflow rate through the device 10 as per the relationship between Effective Area and Pressure given by -EA = C. P-2 where-EA -effective area C -a constant P -Air Pressure The effective area is inversely proportional to the square of the air pressure which provides a polynomial curve as mapped in Figure 13A. Hence the present inventors have discovered that an outlet which matches curve profile of effective area and air pressure relationship would provide a constant or approximately constant outlet airflow.

An example port profile 60 is presented in Figure 12B comprising a generally triangular aperture with a first edge 62 parallel to the longitudinal axis of the housing and two curved edges 64, 66 extending inwardly concave towards each other. Within this embodiment, as the airflow control member 14 restricts the port 60, the reduction in aperture area matches the effective area and pressure relationship such that at a higher pressure the area decreases correspondingly resulting in the port air flow being unchanged.

In another embodiment of the device, the airflow control member 140 may be a swinging cradle as shown in Figure 14. In another embodiment the airflow control member 150 may have a V cross section such the back and front surfaces are subtended at 90 degrees at the apex as shown in Figure 15. In another embodiment the airflow control member 160 may have bell shaped cross section as shown in Figure 16. Figure 17 shows the air control member 14 as per the first embodiment of the device 10 with arcuate ribbing 52 running underneath to provide structural rigidity. In another embodiment the airflow control member 180 may have a U-shaped cross section as shown in Figure 18. In another embodiment the airflow control member 190 may be a swinging cradle with thinned matrices sections running along its length to reduce weight as shown in Figure 19. In another embodiment the airflow control member 200 may have a V-shaped cross section with thinned matrices sections running along its length to reduce weight. In another embodiment the airflow control member 210 may constitute a V-shaped cross section made from ultra-light material with end caps to provide structural rigidity as shown in Figure 21.. In another embodiment the airflow control member 22 there is provided a general U-shaped cross section with a central spine running the full length. Above the pivot point is a counterweight matching the weight of the body as shown in Figure 22.

Figures 23A -23C shows the embodiment of Figures 7A to 7C under reverse flow conditions.

When the air pressure across the outlet 28 is greater than that of the inlet 26, the direction of airflow is reversed and the ventilation device 20 regulates the flow across the inlet passageway 24a'. In Figure 23A, during low air pressure differences across the device 10, the control member 14 remains unmoved and the air flows over the control member 14 exiting through the unrestricted inlet 26.

As shown in Figure 23B, as wind speed/pressure difference increases, the force applied to the front surface 36 of the control member 14 increases, and the control member 14 rotates about the pivot point 48, 50 to restrict the area of the inlet passageway 24a'. Above a certain threshold air pressure the airflow control member 14 rotates to the point where its curved region 44 substantially aligns with the entire inlet passageway 24a' as shown in Figure 23C so that the airflow control member 14 substantially closes the path of the flow towards the inlet 26 from the outlet 28. The control member 14 at this point stops rotating as the air pressure around the member is balanced within the internal cylindrical cavity 19 of the housing 12. The balance of air pressure around the control member 14 (taking account of its weight) results in the control member 14 being suspended in position. In this embodiment a gap 61 is present for air to flow resulting in the reverse air flow not being regulated as much as in the inlet 26 to outlet 28 direction as shown in Figures 7A -7C. However the embodiment in Figure 23C shows that the airflow control member 14 substantially restricts the inlet air passageway 24a' providing a useful amount of airflow control. Other embodiments of the ventilation device may be configured such that gap 60 is absent under reverse flow conditions providing the same level of airflow control as in the inlet 26 to outlet 28 direction. All embodiments of the device disclosed may operate in reverse flow conditions to regulate the airflow through the inlet passageway 24a'.

Figure 24 shows a graph charting the change in airflow for increasing pressure and decrease pressure across the device as per the present disclosure (Figure 2), a 2500EA vent as per Figure 1 and the air pressure operated ventilation device as per GB 2383124A. This shows the current device 10 regulates airflow during both increasing and decreasing pressure flows such that above around 30Pa the airflow rate is substantially constant.

The increasing pressure results for the device as per GB 2383124A mimic the curve for the 2500EA standard vent until around 40Pa where the valve member moves from position FIG. 7A to position FIG. 7K of the GB 2383124A application. Hence, pressure control only occurs between 40Pa and 140Pa when the vent is in its closed position.

Claims

CLAIMS1. A ventilation device for regulating airflow through an opening comprising a housing having a passageway leading from a first port to a second port, one being arranged to act as an inlet and the other as an outlet and an airflow control member, characterised in that the airflow control member in a position thereof is positioned at a first margin of the passageway between the inlet and the outlet to provide free space between the airflow control member and an opposite second margin of the passageway, the airflow control member being configured to restrict the airflow in response to air pressure.
2. A ventilation device as claimed in claim 1 in which the first margin is a lower margin and the second margin is an upper margin.
3. A ventilation device for regulating airflow through an opening comprising a housing having a passageway leading from a first port to a second port, one being arranged to act as an inlet and the other as in outlet and an airflow control member, characterised in that the airflow control member is configured to restrict the airflow travelling above said member in response to air pressure.
4. A ventilation device as claimed in any one of the preceding claims in which the airflow control member is arranged in response to a higher pressure at the inlet than the outlet to move so as to restrict flow towards the outlet from the inlet.
5. A ventilation device as claimed in any one of the preceding claims in which the airflow control member is arranged in response to a higher pressure at the outlet than the inlet to move so as to restrict airflow towards the inlet from the outlet.
6. A ventilation device for regulating airflow through an opening comprising a housing having a passageway leading between a first port and a second port and an airflow control member, characterised in that the airflow control member is configured to control air flow along the passageway in response to the air pressure difference across the device in either direction, whether the flow is from the first port to the second port and vice versa.
7. A ventilation device as claimed in any one of the preceding claims, in which the housing comprises a first part and a second part.
8. A ventilation device as claimed in any preceding claim, in which the housing includes a circular cross section region, an inlet and an outlet, the housing optionally providing an internal cylindrical cavity.
9. A ventilation device as claimed in 8, in which the housing further comprises a cuboidal section providing fluid communication between the inlet and the internal cylindrical cavity.
10. A ventilation device as claimed in 8 or 9, in which the housing further comprises a cuboidal section providing fluid communication between the internal cylindrical cavity and the outlet.
11. A ventilation device as claimed in any one of claims 8 to 10, in which the inlet and outlet are formed on opposite sides of the circular cross section centre.
12. A ventilation device as claimed in any one of the preceding claims, in which the airflow control member comprises an elongate structure extending along the housing.
13. A ventilation device as claimed in claim 12, in which the airflow control member has a generally V-shaped cross section comprising a front surface and a back surface meeting at an acute angle apex.
14. A ventilation device as claimed in claim 13, in which the ends of the airflow control member comprise a curved edge adjoining the front and back surfaces.
15. A ventilation device as claimed in claim 14, in which the projected area of the curved edge along the length of the airflow control member is substantially equal to the area of the housing outlet.
16. A ventilation device as claimed in claim 14 or 15, in which the curvature of the curved edge of the control airflow member is equal or slightly less than to the curvature of internal cylindrical cavity of the housing and optionally in which the curved edge is an arc.
17. A ventilation device as claimed in any preceding claim, in which the airflow control member is self-adjustable between a fully exposed outlet and a substantially restricted outlet.
18.. A ventilation device as claimed in any preceding claim, in which the airflow control member is adapted to pivot about the central longitudinal axis of the housing.
19. A ventilation device as claimed in any preceding claim, in which the airflow control member rests below or in line with a pivot point thereof.
20. A ventilation device as claimed in claim 13 or any other preceding claim dependent upon claim 13, in which the outlet has a surface positioned immediately after the resting position of the front surface of the airflow control member.
21. A ventilation device as claimed in any preceding claim, in which airflow control member is arranged to move gradually in response to gradual changes in air pressure.
22. A ventilation device as claimed in claim 8 or any preceding claim when dependent upon claim 8, in which the airflow control member is arranged to rotate to substantially completely restrict the outlet, being held in position by the balance of air pressure within the internal cylindrical cavity taking account of the weight of the control member.
23. A window or door assembly (or building assembly) in which there is a ventilation slot extending from one side of the assembly to the other and a ventilation device as claimed in any preceding claim mounted on the assembly in the region of the ventilation slot.
24. An assembly as claimed in claim 23 which comprises a building wall or roof assembly.
25. An assembly as claimed in claim 23 which comprises a building facade assembly.
26. A pivot joint assembly suitable for ventilation devices comprising a pin and a hole characterised in that the pin has a smaller diameter than the hole.
27. A pivot joint assembly as claimed in claim 26, in which the depth of the hole does not exceed the length of the pin.
28. An air port having an aperture and a member for restricting the aperture, the aperture and/or member being shaped so that upon equal movements of the member relative to the aperture, unequal restrictions to the area for flow through the aperture are made.
29. An air port profile as claimed in claim 28 wherein the aperture profile matches the shape of the graphical relationship between Effective area and Air pressure as follows-EA = C. P-2 where-EA -effective area C -a constant P -Air Pressure
30. An air outlet profile as claimed in claim 29 wherein the aperture is generally triangular with a straight base edge and two inwardly concave curved edges.