VENTILATION DEVICE
A device is described for controlling the airflow through an airduct, the airduct having a housing, an inlet and an outlet. The device comprises a self-regulating valve having a diaphragm, the position of the diaphragm being determined by the difference between the pressure at the inlet and the pressure at the outlet. The diaphragm is rotatably suspended on a support so that, under influence of an increasing difference in pressure, the diaphragm can rotate between a minimum rotation angle and a maximum rotation angle over an intermediate rotation angle, the intermediate angle being situated between the minimum and maximum angle. The diaphragm is provided with a counterbalance and that, within the angle range between the intermediate rotation angle and the maximum rotation angle, the rotation movement of the diaphragm under influence of an increasing pressure difference is counteracted by an elastic resisting force.
This invention relates to a ventilation device which can regulate airflow as well as to a method of controlling air flow through a ventilation device and to an insert for a ventilation device that provides control of the air flow.
BACKGROUND TO THE INVENTIONVentilation devices are widely used in the walls and windows of buildings to allow fresh air to enter a building. In many countries, the use of a ventilator is recommended or mandatory. Standards can also define certain requirements for the performance of a ventilator. One such requirement defines the performance of the ventilator in terms of airflow rate versus pressure difference between the inlet and outlet of the device. Typically, there is a requirement for a constant, or a near constant, airflow rate across a range of pressure differences. This requirement will provide a user with a pleasing environment within a building, with a constant flow of air, regardless of weather conditions outside the building. One requirement is that the inflow of air should reach a limit as the incoming wind speed increases while maintaining good ventilation at low speeds. Hence, the flow characteristic of the valve should be non-linear and self-limiting.
A ventilation device typically comprises a housing which defines an airflow duct. A valve is positioned within the flow duct. The position of the valve can be controlled by a pressure monitor and an actuator (e.g. an electrical actuator or motor) or the valve can be self-regulating, without the use of an actuator. A self-regulating ventilation device is described in EP 1 568 947 B1. A valve is rotatingly suspended about a suspension point in the air duct. The valve is arranged to move in the air duct. The valve firstly rotates to a maximum turning angle around the free suspension point, and then subsequently deforms, without further rotation about the free suspension point. Operation of this ventilation device relies on the flexibility of the valve, formed from plastic. However, as the properties of the valve part vary with temperature, the performance of this ventilation device can vary as temperature fluctuates.
It is desirable that a ventilation device has a good performance (e.g. offering near-constant flow rate across a wide range of pressure differences) and is capable of being manufactured at low cost.
SUMMARY OF THE INVENTIONA first aspect of the present invention provides a device for controlling the airflow through an airduct, the airduct having a housing, an inlet and an outlet, the device comprising:
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- a self-regulating valve having a diaphragm, the position of the diaphragm being determined by the difference between the pressure at the inlet and the pressure at the outlet, the diaphragm being rotatably located, e.g. journalled or suspended, on a support so that, under influence of an increasing difference in pressure, the diaphragm can rotate between a minimum rotation angle and a maximum rotation angle over an intermediate rotation angle, the intermediate angle being situated between the minimum and maximum angle, and characterized in that the diaphragm is provided with a counterbalance and that, within the angle range between the intermediate rotation angle and the maximum rotation angle, the rotation movement of the diaphragm under influence of an increasing pressure difference is counteracted by an elastic resisting force.
A ventilation device of this kind has been found to provide a well-regulated flow of air across a wide range of values of pressure difference. In particular, it has been found to offer a plateau at high pressure differences (i.e. values of external wind speed). The counterbalance helps to ensure that the valve member does not unduly restrict the air duct at low values of pressure difference, and can readily respond to changes in pressure difference at the lower values of pressure difference.
The elastic resisting force can be generated by contact between the counterbalance, or the diaphragm, and a resilient means. The resilient means may be a spring of any suitable form. The resilient means can be attached to, or form part of, the housing. Alternatively, the elastic resisting force can be generated by contact between a part of the housing and a resilient means which forms part of, or is mounted to, the counterbalance or diaphragm. For example, the resilient means can be provided by a part of the counterbalance or diaphragm which is formed from a resilient material, such as a resiliently deformable plastic material. In either case, the resilient means can be a spring.
Preferably, the resilient means provides substantially constant performance over a normal operating temperature range, e.g. −20° C. to +40° C. A resilient means formed of metal has been found to be particularly advantageous. The spring properties of the resilient means preferably change by less than 20%, or less than 10% over the range −20° C. to +40° C. or for some temperate countries 0-35° C.
In an alternative embodiment of the invention, the elastic resisting force is provided by a part of the counterbalance which is formed from a resilient material, such as a resiliently deformable plastic material.
Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:
The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.
Hooked part 11 of the valve is shaped to define the angular range over which the valve can move. Wall 17 of the hooked part 11 defines the rest position of the flap 12, when there is little or no pressure difference. Wall 18 of the hooked part 11 defines the maximum turning position of the flap 12, as the flap 12 rotates in the clockwise direction about support 10. Additional stops can be provided, such as protrusions extending from the wall of housing 5 in the region of the resting position of the flap 12.
A further embodiment of the ventilation device (not shown) resembles the device shown in
Each of the illustrated embodiments show a counterbalance acting upon a resilient member, or a counterbalance which incorporates a resiliently deformable portion. However, this is not essential to the invention and, instead, the flap (diaphragm) can act upon a resilient member.
In
The ventilation device can be fitted to a building, with the housing 5 being adapted to fit within a wall of the building, in the frame of a window, or in the window itself. Portions 51, 52 of the housing fit within the wall, frame or window, with portion 53 extending into the interior of the building and portion 54 extending outside the building. The inlet 1, 101 to the device is preferably vertically oriented, which serves to prevent ingress of water.
In the illustrated embodiments, the counterbalance is arranged to position the valve member at an inclined position when the pressure difference has a low or zero value. This allows the exterior portion 54 of the housing surrounding the valve member to have a generally arcuate profile, which reduces the amount of material used to form this region (compared to a more rectangular profile), allows water to run off the housing and generally gives a more pleasing aesthetic appearance.
Although a housing 5 has generally been described, this can be formed from a plurality of different physical parts which can be secured together, such as by snap fittings, screws, clips etc. For example, there can be an upper part and a lower part which, when fitted together, define the airflow duct. Parts can be formed from different materials. For example, the outermost shell of the housing can be formed from aluminum, with other parts formed in plastics materials such as PVC.
Further embodiments of the ventilation device can comprise measures to acoustically dampen the air flow. Acoustic dampening can be achieved by lining the airflow duct 4, 104, with acoustically absorbent material or by including acoustically absorbent material in the outlet 2 or grille 3; by including obstructions (or acoustically absorbent material) in the airflow duct etc. An embodiment of an acoustic device is shown in
Another embodiment of a ventilation device is shown in
A ventilation according to
The invention is not limited to the embodiments described herein, which may be modified or varied without departing from the scope of the invention.
Claims
1. Device for controlling the airflow through an airduct, the airduct having a housing, an inlet and an outlet, the device comprising
- a self-regulating valve having a diaphragm, the position of the diaphragm being determined by the difference between the pressure at the inlet and the pressure at the outlet
- the self-regulating valve being rotatably located on a support so that, under influence of an increasing difference in pressure, the diaphragm can rotate between a minimum rotation angle and a maximum rotation angle over an intermediate rotation angle, the intermediate angle being situated between the minimum and maximum angle,
- wherein the valve is provided with a counterbalance and wherein,
- within the angle range between the intermediate rotation angle and the maximum rotation angle, the rotation movement of the valve under influence of an increasing pressure difference is counteracted by an elastic resisting force, and
- wherein the elastic resisting force is generated by contact between a part of the housing and a resilient means which forms part of, or is mounted to the counterbalance or diaphragm and wherein the resilient means comprises a part of the counterbalance or diaphragm which is formed from a resilient material.
2. The device of claim 1, wherein the support is a hinge.
3. The device of claim 1, wherein the elastic resisting force is generated by contact between said counterbalance, or said diaphragm, and the resilient means.
4. The device of claim 3 wherein the resilient means are attached to, or form part of, the housing.
5. The device according to claim 1, wherein the resilient means provides substantially constant performance over a temperature range of −20° C. to +40° C.
6. The device according to claim 5, wherein the substantially constant performance of the resilient means is a change of less than 20% in spring constant over the temperature range of −20° C. to +40° C. or 0° C. to 35° C.
7. The device according to claim 1, wherein the resilient means are formed of metal.
8. The device according to claim 1, wherein the counterbalance is dimensioned so as to keep the diaphragm at the minimum rotation angle when the pressure difference has a low or zero value.
9. The device according to claim 1, wherein the flow characteristic of the valve is non-linear and self-limiting.
10. The device according to claim 1, wherein the flow rate through the device remains substantially in a range defined by between 4 and 7 litres/s over a pressure range of 2 to 25 Pa.
11. The device according to claim 1 wherein the flow rate through the device varies by less than ±60%, less than ±50% or less than ±40% over a pressure drop range ratio of 5:1, or 10:1.
12. Device for controlling the airflow through an airduct, the airduct having a housing, an inlet and an outlet, the device comprising
- a self-regulating valve having a diaphragm, the position of the diaphragm being determined by the difference between the pressure at the inlet and the pressure at the outlet
- the self-regulating valve being rotatably located on a support so that, under influence of an increasing difference in pressure, the diaphragm rotates between a minimum rotation angle and a maximum rotation angle over an intermediate rotation angle, the intermediate angle being situated between the minimum and maximum angle,
- wherein the valve is provided with a counterbalance and wherein,
- within the angle range between the intermediate rotation angle and the maximum rotation angle, the rotation movement of the valve under influence of an increasing pressure difference is counteracted by an elastic resisting force,
- wherein the elastic resisting force is generated by contact between a part of the housing and a spring which forms part of, or is mounted to the counterbalance or diaphragm, and
- wherein the spring comprises a part of the counterbalance or diaphragm which is formed from a resilient material.
13. The device of claim 12, wherein the support is a hinge.
14. The device of claim 12, wherein the elastic resisting force is generated by contact between said counterbalance, or said diaphragm, and the spring.
15. The device of claim 14 wherein the spring is attached to, or forms part of, the housing.
16. The device according to claim 12, wherein the spring provides substantially constant performance over a temperature range of −20° C. to +40° C.
17. The device according to claim 16, wherein the substantially constant performance of the spring is a change of less than 20% in spring constant over the temperature range of −20° C. to +40° C. or 0° C. to 35° C.
18. The device according to claim 12, wherein the spring is formed of metal.
19. The device according to claim 12, wherein the counterbalance is dimensioned so as to keep the diaphragm at the minimum rotation angle when the pressure difference has a low or zero value.
20. The device according to claim 12, wherein the flow characteristic of the valve is non-linear and self-limiting.
Type: Application
Filed: Oct 16, 2008
Publication Date: Apr 16, 2009
Inventor: Bart LAMBRECHT (Waregem)
Application Number: 12/252,855
International Classification: F24F 13/10 (20060101);