VALVE FOR CONTROLLING A VENTILATION STREAM

Abstract

 Valve for controlling a ventilation stream (100) through an opening (102), wherein the opening (102) is delimited by an edge (201, 301) and has a central axis in the axial direction (101), the valve comprising:
- a frame (900, 1200) comprising a static portion (902, 1202) adapted to mount the valve;
- at least one blade (500, 600) which is connected to the frame (900, 1200), such that in mounted condition of the valve, the blade (500, 600) is movable along the edge (201, 301), wherein a segment (202, 302) of the opening (102) is closed to the ventilation stream (100) by means of the blade (500, 600), wherein the blade (500, 600) comprises a flexible material, and the frame (900, 1200) comprises a movable element (901, 1201) adapted to fold the flexible material in such a way that the surface of the closed segment (202, 302) is changed.

Description

Technical field

[0001] The present invention generally relates to a valve for controlling a ventilation stream through an opening. In particular, the invention provides a solution for a controllable valve which is compact, allows energy-efficient control and offers good resistance to soiling.

Background of the invention

[0002] Ventilation systems are used, for example, to control the air quality in rooms of a building. In the simplest embodiment, air is continuously extracted from the space for as long as the fan is in operation. In a more advanced system, air is extracted as required from every room, for example on the basis of a measured CO₂ or moisture content. Fresh air is then accordingly introduced, for example via window ventilators. In order to make it possible to control the amount of extracted air for each room, controllable valves are typically used. A central fan may then operate continuously while the ventilation stream is controlled from one room by adjusting a valve in each room. In this case, a valve may be mounted in a tube, in a position close to the central fan, so that the electrical power supply to the fan and valves may be achieved without excessive use of cabling. In another embodiment, autonomous operation of a valve is possible. In this case, for example, the air stream is used to drive a small generator and the (stored) electrical energy is used to operate the valve. With such an autonomous system, a valve may be mounted far from the central fan, for example in a tube at a position close to the room, or in a wall or ceiling of the room.

[0003] Controlling a valve means that the size of the opening which allows the passage of air is adjusted. Typically, one or more blades, leaves or plates are used, the position of which is adjustable and which thus modify the size of the passage opening. Various variants of such controllable valves are known. A first variant uses a tilting principle. An example thereof is a butterfly valve, in which a disc-shaped blade is mounted tilted about an axis according to a diameter of the round opening. In another example of the tilting principle, use is made of several rectangular plates which are each rotatable about an axis transversely across the opening. In a second variant, a sliding principle is used, in which case, for example, a rectangular blade slides in the plane of a rectangular opening and thus gradually closes off the opening. A mechanical iris valve also uses a sliding principle: several triangular blades arranged around the periphery slide along one another and thus increase or reduce a central opening. Finally, a third variant uses a stacking principle. For example, several blades are attached to a central point in a round opening. By rotating the blades about the central point, the blades slide behind one another and they are stacked on top of each other. In a largest open position of the valve, all blades are stacked on top of each other. An example of a solution using such a stacking principle is found in US 2007/190927. The latter document also discloses yet another variant, in which fold lines are applied into a rigid material, such that a solution comparable to a Japanese hand-fan is obtained.

[0004] In each of the above variants, the blades or plates are made of a rigid material, which makes the blade or plate relatively heavy. Due to the weight as such and due to the friction which this weight causes, a significant amount of energy is consequently required to bring about a movement of the blade or plate and thus to control the valve. This is a drawback, not only with regard to the general consumption of electrical energy, but in particular for autonomous systems, in which the amount of available energy is limited. In addition, such valves have the drawback that they become soiled over the course of time, because dirt and dust stick to the blades or plates. Finally, many of these known solutions have the drawback that they take up a large amount of space. For example, with the tilting principle of the butterfly valve, space has to be available in a longitudinal direction in order to allow the blade to tilt completely in the open position of the valve. This renders installation in locations which only have little space in a longitudinal direction available more difficult, for example in a wall or ceiling having limited thickness. The sliding principle in turn requires space next to the opening, so that the blade or blades are able to slide out in the open position of the valve. The stacking principle offers a more compact system, but does not offer a solution with regard to the energy requirement and soiling of the blades. In addition, there may be a gap between two stacked blades, so that air finds a way through the closed segment of the opening. This makes a controlled passage of ventilation air more difficult and may possibly result in undesirable flow patterns.

[0005] It is an object of the present invention to describe a solution which overcomes one or more of the described drawbacks of prior-art solutions. More specifically, it is an object of the present invention to describe a valve for controlling a ventilation stream through an opening which is compact, allows energy-efficient control and has a good resistance to soiling.

Summary of the invention

[0006] According to the present invention, the objects identified above are achieved by a valve for controlling a ventilation stream through an opening, as defined by Claim 1, wherein the opening is delimited by an edge and has a central axis in the axial direction, and the valve comprises:

• a frame comprising a static portion adapted to mount the valve;
• at least one blade which is connected to the frame, such that in mounted condition of the valve, the blade is movable along the edge of the opening, wherein a segment of the opening is closed to the ventilation stream by means of the blade,

wherein:
the blade comprises a flexible material, and the frame comprises a movable element adapted to fold the flexible material in such a way that the surface of the closed segment is changed.

[0007] In other words, the invention relates to a valve for controlling a ventilation stream through an opening. The opening is delimited by an edge. For example, the opening of a tube is delimited by the tube wall, or an opening in a wall or ceiling is delimited by the material of the respective wall or ceiling. Various shapes are possible, for example a round opening, a rectangular opening, etc. The opening has a central axis which also defines the average flow direction when air flows through the opening in the absence of a valve. The direction of this central axis is defined as the axial direction. For example, in the case of a cylindrical tube, the opening is situated in a transverse plane and the ventilation stream flows through the tube along an axial direction of the cylinder. In the case of an opening in a wall, the axial direction is the longitudinal direction of a duct defined by the edge of the wall which delimits the opening. A ventilation stream is typically an air stream, in which the movement of air is caused, for example, by a fan. By means of the valve, the opening is closed to a greater or lesser degree, so that a larger or smaller passage opening is created.

[0008] The valve comprises a frame, wherein this frame comprises a static portion adapted to mount the valve. A frame is typically made of a rigid material. Mounting the valve refers to attaching the valve to a fixed element in the environment by means of construction elements contained in the static portion of the frame. For example, the valve is placed in the tube opening, in which case the static portion of the frame is attached to the inner wall of the tube. In another example, the static portion of the frame is attached to a wall or ceiling.

[0009] The valve comprises at least one blade connected to the frame. The valve thus contains one or more blades or leaves, and each of the blades is connected to the frame. The frame thus ensures that the one or more blades are held in position, but this position is actually variable. Typically, a blade is partly connected to the static portion of the frame and partly to a movable element contained in the frame.

[0010] The blade is movable along the edge of the opening and, by means of the blade, a segment of the opening is closed to the ventilation stream. A segment of the opening is a part of the opening, for example a segment of a circle in the case of a round opening, or a fraction of a square in the case of a duct with a square cross section. By means of a blade, a segment of the opening can be closed to the ventilation stream, i.e. the blade blocks the ventilation stream in that location. The blade is movable, which means that at least a part of the blade can be moved. By means of such movement, a closed segment is increased or reduced in size. The direction of movement of the blade is along the edge of the opening. This means that, for example in the case of a round opening, the blade can move in circumferential direction by rotating about a central point. In another example, the opening is rectangular and the direction of movement is determined by a translation along two opposite edges of the opening. By contrast, a solution in which a central opening is increased or reduced in size does not allow movement along the edge of the opening, since in the case of such a solution, a blade is attached to the edge of the opening and can only move in a direction perpendicular to the edge.

[0011] A blade comprises a flexible material, implying that the blade is at least partly made of a flexible material. This means that a blade is made entirely from a flexible material or is partly made from flexible material and partly comprises rigid material, for example as local reinforcement. A flexible material is a material which can easily be folded at any arbitrary location on the material. Therefore, the flexible material present in the blade does not comprise any predefined fold lines. Examples of a flexible material are a fabric, cloth, leather, a flexible type of plastic such as plastic film or TPE (Thermoplastic Elastomer), etc. As such, a flexible material refers to a non-stiff material, or the opposite of a rigid material. The flexible material can be folded without requiring any predefined fold lines, and unfolding does not leave any traces of plastic deformation. The folding thus involves purely an elastic deformation of the material, and the folds that are formed typically have a rounded, non-sharp shape at their tip. During folding, the shape of the fold may change, or the fold may be displaced throughout the material. Moreover, folding of the flexible material is easy, in the sense that no substantial force is needed for folding, and that the folded material does not show large tendency to bounce back to the unfolded condition. In case the blade is not made entirely of a flexible material, but also contains one or more rigid portions, typically the surface of the blade occupied by flexible material is larger than the surface occupied by rigid material. Thus, in such a case the rigid material only serves as a local reinforcement while the blade is mainly provided in flexible material.

[0012] In addition to a static portion, the frame comprises a movable element. The movable element is adapted to fold the flexible material in such a way that the surface of the closed segment is changed. A movable element is a component which can be moved with respect to the static portion. Various types of movement are possible, for example a rotating movement, a linear translation, etc. The movement may be driven, for example by an electrical motor, or may be brought about manually. Folding refers to producing or displacing a fold in the flexible material. It is thus possible to start from a completely unfolded state, or from a folded state and then to proceed to a different folded state. In different embodiments, various types of folding are possible. For example, the flexible material may be folded over, in which case one fold is displaced through the flexible material in a direction along the plane of the blade, or two folds may be displaced through the flexible material along the plane of the blade. In another embodiment, folding takes place in accordance with the principle of an accordion or Chinese fan. This produces multiple folds which displace in the axial direction. Combinations of different types of folding are also possible. In each of the embodiments, the surface of the closed segment, measured in a transverse plane perpendicular to the axial direction, is changed due to the folding of the flexible material. In this way, folding makes it possible to increase or reduce the size of the passage opening which is available for the ventilation stream by moving the movable element.

[0013] The valve according to the invention has various advantages. A first advantage is the fact that the solution is compact. Thus, less space is required in the axial direction than is the case with, for example, the tilting principle of a butterfly valve. Actually, if the flexible material is folded, for example, so as to form two or more layers of flexible material on top of each other in the axial direction, only these stacked layers occupy space in the axial direction. In the embodiment in which the flexible material is folded in accordance with the principle of an accordion or Chinese fan, the material is displaced in the axial direction, but it takes up less space as several folds are formed. In addition, no additional space is required with any of the embodiments in the plane next to the opening, since the flexible material always stays within the edge of the opening. A second advantage is the fact that the flexible material from which the blade or the blades are made is typically a lightweight material. A rigid material is typically heavier or requires a costly special type of material if the material is to be light. The result of the lightweight flexible material is that a limited amount of energy is required to change the position of a blade and thus to adjust the valve. This is advantageous, for example, for autonomous systems which only have a limited energy supply at their disposal. A third advantage is the fact that the valve offers good resistance to soiling. Indeed, dirt or dust which has become stuck to a blade is released again due to the deformation of the flexible material during folding. A fourth advantage is the fact that the position of the blades cannot be changed by the air stream itself. For example, in the case of a butterfly valve with tilting principle, the approaching air flow may cause the blade to pivot if there is a forceful gust of wind. Finally, a segment is always closed by means of a blade made of one piece of material, so that there are no gaps in the blade through which air may flow in an undesirable manner.

[0014] Optionally, according to Claim 2, the movable element is adapted to fold the flexible material in such a way that, at least for certain opening positions of the valve, multiple layers of the flexible material are present in the axial direction, over at least a portion of the segment. This means that, viewed in the axial direction, multiple layers of flexible material are present, stacked on top of each other. These layers do not have to be present across the entire segment. For example, with a circular opening, several layers are present in the axial direction at a certain circle radius, whereas there is only one layer in the axial direction at another circle radius of the segment. It is also possible that, in a certain opening position of the valve, for example a closed position in which the flexible material is completely unfolded, there is no plurality of layers of flexible material in the axial direction. Various embodiments are possible, for example in which the flexible material is folded over and in this case two layers stacked on top of each other in the axial direction are produced. When folding over, a portion of the flexible material is folded backwards, in the direction of a more downstream position, or folded forwards, in the direction of a more upstream position. In another embodiment, two folds are formed which displace in the plane of the blade, in order to form three layers stacked on top of each other in the axial direction. Using a folding principle which produces multiple layers in the axial direction has the advantage that material is displaced in the plane of the blade, not in the axial direction, so that only the stacked layers take up space in the axial direction. This contributes to a compact solution.

[0015] Optionally, according to Claim 3, the movable element is adapted to during the folding, move a first part of said flexible material to a position behind a second part of said flexible material, wherein in that position, the first part is shielded from the approaching ventilation stream by the second part, or to a position in front of the second part, wherein in that position, the first part is situated on the side of the approaching ventilation stream. This means that the folding takes place in such a way that parts of the flexible material are placed on top of each other or are placed behind one another. During this process, multiple layers of flexible material are formed, viewed in the axial direction. Various embodiments are possible in which two or several layers are formed. In one embodiment, the movement takes place in such a way that the portion of flexible material which is displaced is moved backwards, in the direction of a more downstream position. In this case, the displaced first part is shielded from an approaching ventilation stream by the second part which was not displaced. Consequently, the part of the blade on which the ventilation stream impinges remains flat. On the rear of the valve, the protected portion of flexible material may be flat or may be in a folded or rolled-up state. In another embodiment, the movement takes place in such a way that the portion of flexible material which is displaced is moved forward, in the direction of a more upstream position. In this case, the displaced first part is situated on the side of the approaching ventilation stream after the displacement.

[0016] Optionally, according to Claim 4, the movable element is adapted to displace one or more folds in the flexible material during folding, along a direction of movement situated in a plane substantially perpendicular to the axial direction. For example, a flexible material is folded over at an end, wherein the formed fold will move along the plane of the blade, substantially perpendicular to the axial direction. In another embodiment, the flexible material is folded in such a way that two folds are produced which move along the plane of the blade, substantially perpendicular to the axial direction. Combinations are also possible, with several folds which move in the plane of the blade, substantially perpendicular to the axial direction. Substantially perpendicular refers to a direction of movement which, in a theoretical embodiment, is situated in a plane perpendicular to the axial direction, but may, in practice, deviate slightly therefrom, for example due to certain curvatures which are present in the flexible material. In other words, it is intended to achieve a direction of movement in a plane perpendicular to the axial direction. This is contrary to a solution in which the intended direction of movement of the folds runs parallel to the axial direction, as is the case with the principle of accordion folding.

[0017] Optionally, according to Claim 5, the one or more folds are not in contact with the movable element during displacement of the folds. This means that the folds which are formed during folding are not guided by the movable element and can thus move freely. This has the advantage that a folded blade can, to some degree, flutter freely at the location of the fold. In this way, dirt or dust which has become stuck to a blade is released again, or there is less risk of dirt sticking. The freedom of movement of the folded blade also ensures that there are fewer points of contact, as a result of which less friction occurs and the energy requirement needed for control is lower.

[0018] Optionally, according to Claim 6, the movable element is adapted to move one fold situated on an edge of the segment, and two layers are present in the axial direction. This means that a blade is folded over at one of its ends, producing a fold situated on the edge of the closed segment, and two layers stacked on top of each other are created, viewed in the axial direction. The fold is displaced further along a direction situated in the plane of the blade, substantially perpendicular to the axial direction. This embodiment allows for a straightforward construction, using a limited number of components and simple control means. This contributes to an inexpensive and strong solution. In addition, there are a limited number of moving components, which reduces the weight and thus reduces the amount of energy required to bring about a change in position.

[0019] Optionally, according to Claim 7, the movable element is adapted to move two folds, and three layers are present in the axial direction. For example, an S shape is created in the flexible material, comprising two folds which move in the plane of the blade, substantially perpendicular to the axial direction. Thus, three layers of flexible material stacked on top of each other in the axial direction are created. In this case, the two folds are not on the edge of the segment, but each is situated at a different position within the segment. As three stacked layers are formed, this embodiment has the advantage that, in a completely open position of the valve, only a limited part of the opening is still closed off by the blade. Thus, a large passage opening is produced for the ventilation stream when the valve is in its completely open position.

[0020] Optionally, according to Claim 8, the movable element is adapted to move two folds, so that the folds move simultaneously and in the same direction. For example, an S shape is created in the flexible material, in which case the two formed folds move simultaneously in the plane of the blade. This has the advantage that there is only one direction of movement, which can be achieved by one motor.

[0021] Optionally, according to Claim 9, the flexible material comprises a fabric material and/or a flexible type of plastic. A fabric material is, for example, cloth, textile or leather, a flexible type of plastic is, for example, TPE (Thermoplastic Elastomer) or a plastic film. A blade may be made entirely from flexible material, or partly from a flexible material and partly from a rigid material, for example as a local reinforcement. In various embodiments, the blade has a constant thickness, measured in the axial direction, or it has local thickened or thinned portions.

[0022] Optionally, according to Claim 10, a blade comprises a rigid material positioned at one or more edges of the blade, wherein the rigid material adjoins the flexible material. This means that a blade is composed of different types of materials. For example, the blade comprises a central part made of flexible material, and one or more parts at the ends or edges of the blade made of a rigid material. In an embodiment, the parts located at the edges of the blade consist of a hard piece of plastic. For example, the parts made of rigid material are found at the location where the blade is connected to the frame. This contributes to a straightforward and strong attachment to the frame and a local reinforcement of the blade. On the one hand, the blade can then easily be folded in the flexible part, and on the other hand absorbs loads at the location of the rigid part.

[0023] Optionally, according to Claim 11, the blade is attached to the static portion of the frame at at least one position and is attached to the movable element at at least one other position. For example, the blade is fixed on one side by being attached to the static portion, and the blade is movable on another side by being attached to the movable element. By moving the movable element, the side of the blade which is connected hereto is moved and the one or more folds are formed.

[0024] Optionally, according to Claim 12, the valve is adapted to move the movable element according to a rotating movement. This means that the movable element comprises components which rotate, for example about a central point in the opening. A rotating movement can easily be produced by means of the rotating axle of a motor. This provides a simple embodiment, without requiring, for example, linear guides. Also, the rotating movement can readily be adapted to closing off a round opening, which is a current form.

[0025] Optionally, according to Claim 13, the static portion comprises one or more static arms which are elongated in the radial direction, and the movable element comprises one or more movable arms which are elongated in the radial direction, and the valve is adapted to rotate the one or more movable arms about a central point. For example, the frame comprises a central component, which is positioned centrally in the opening, and one or more radial arms are attached to this central component. At least one of these arms is static, and at least one of these arms is rotatable about the central component, for example by means of a motor at the location of the central component.

[0026] Optionally, according to Claim 14, the valve comprises one static arm and one movable arm for each blade, or two static arms and two movable arms. In one embodiment, the valve has one static radial arm and one movable radial arm for each blade. For example, the blade is attached to the static arm on one side and to the movable arm on its other side. By rotating the movable arm about a central point, the blade is folded. In another embodiment, the valve has two static radial arms and two movable radial arms for each blade. For example, the blade is attached to at least one of the static arms on one side and to at least one of the movable arms on its other side. By rotating the movable arms about a central point, the blade is folded, creating two folds.

[0027] Optionally, according to Claim 15, the valve comprises multiple blades, preferably four blades. For example, the four blades are positioned symmetrically, so that each blade regulates the passage through a quarter of a circular opening. This has the advantage that a simple construction is achieved with a small necessary angular rotation, at most 90°, in order to move from a fully open to a fully closed position. In this case, a simple control unit is possible, with one motor being able to control the four blades simultaneously. Due to the limited surface of one piece of flexible material, this is also straightforward to fold up and unfold. In addition, the fraction of the opening which is closed by the blades when the valve is in its fully open position is smaller than when a smaller number of blades is used. This ensures a good through-flow in the open position of the valve. Finally, a symmetrical arrangement also ensures a favourable weight distribution, which prevents the flexible material from sagging. This contributes to the strength and durability of the solution.

Brief description of the drawings

[0028] 

Fig. 1 illustrates an opening through which a ventilation stream flows.

Fig. 2 and Fig. 3 each show a possible form of opening, which can be closed by means of a valve according to an embodiment of the invention.

Fig. 4 illustrates how a blade made of flexible material is folded according to a principle of single folding or folding over, in one possible embodiment of the invention.

Fig. 5 to Fig. 8 illustrate possible folding principles which can be used in various embodiments of the invention. Fig. 5 illustrates the principle of single folding or folding over. Fig. 6 illustrates the principle of double folding. Fig. 7 illustrates a combination of single and double folding. Fig. 8 illustrates the folding according to the principle of an accordion or Chinese fan.

Fig. 9 to Fig. 11 show an embodiment of a valve according to the invention which uses the principle of single folding or folding over. Fig. 9 shows a front view and a rear view. Fig. 10 shows three different positions, corresponding to three different opening positions of the valve. Fig. 11 shows how the flexible material of a blade is folded at different opening positions of the valve.

Fig. 12 to Fig. 14 show an embodiment of a valve according to the invention which uses the principle of double folding. Fig. 12 shows a front view and a rear view. Fig. 13 shows three different positions, corresponding to three different opening positions of the valve. Fig. 14 shows how the flexible material of a blade is folded at different opening positions of the valve.

Detailed description of the embodiments

[0029] Fig. 1 shows an opening 102, for example an opening 102 in a tube, wall, or ceiling. The opening is delimited by an edge 103. Various forms are possible for the cross section of the opening, transversely in Fig. 1. For example, Fig. 2 shows a rectangular opening and Fig. 3 shows a round opening. A ventilation stream 100 flows through the opening 102. By mounting a valve, the opening can be closed partly or completely. In the absence of a valve, the ventilation stream, on average, flows in a rectilinear way, denoted in the figure as the axial direction 101.

[0030] Fig. 2 illustrates an opening 102 with a rectangular cross section perpendicular to the axial direction 101. The opening has an edge 201. The figure illustrates how, by means of a blade 200, a segment 202 of the opening is closed to the ventilation stream 100. In this case, the blade 200 moves linearly and follows a direction of movement parallel to two opposite sides 203 comprised in the edge 201. In the opening position, denoted by (a), the blade 200 is in the folded position, in which a large part of the opening is available for through-flow. In the opening position, denoted by (c), the blade 200 is in an unfolded state and the opening is (virtually) completely closed to the ventilation stream 100. Regulations may stipulate that the opening should never be closed completely and should always allow a limited ventilation stream 100 to pass through.

[0031] Fig. 3 illustrates an opening 102 with a round cross section, perpendicular to the axial direction 101. The opening has an edge 301. The figure illustrates how, by means of a blade 300, segments 302 of the opening are closed to the ventilation stream 100. In the illustrated embodiment, there are four blades 300, and thus four closed segments 302. The figure illustrates how the valve moves from an open position (a) to a closed position (c). In this case, a blade 300 moves along the edge 301, i.e. along the circumferential direction of the circle. In the opening position, denoted by (a), the blades 300 are in the folded position, in which a large part of the opening is available for through-flow. In the opening position, denoted by (c), the blades 300 are in an unfolded position and the opening is (virtually) completely closed to the ventilation stream 100. Regulations may stipulate that the opening should never be closed completely and should always allow a limited ventilation stream 100 to pass through.

[0032] Fig. 4 furthermore illustrates how, in the case of a round opening as shown in Fig. 3, a blade 300 can be folded in order to increase or reduce the surface of a closed segment 302 in size. The blade 300 is made from a flexible material. In the embodiment from Fig. 4, only one blade 300 is illustrated, and the principle of single folding or folding over is used. The top half of Fig. 4 shows a front view, perpendicular to the axial direction 101. The bottom half of Fig. 4 shows a cross section along a circular arch 404. On one side, the blade 300 is attached to a static arm 400, which remains stationary with respect to the edge of the opening. On its other side, the blade 300 is attached to a movable arm 400, which can be rotated about a central element 403. In the position denoted by (a), the blade 300 is unfolded. During opening of the valve, the movable arm 401 is rotated and the blade 300 is folded over. This produces a fold 402 in the flexible material. Position (b) shows that the fold 402 is situated on an edge of the closed segment 302. Position (b) also shows that, in the greatest open position of the valve, with four blades 300 being present, approximately half of the opening is available for through-flow and approximately half of the opening is closed to the ventilation stream 100.

[0033] In addition to the principle of single folding or folding over with the formation of one fold 402, as is illustrated in Fig. 4, other folding principles are also possible within various embodiments of the invention. A number of folding principles are illustrated in Fig. 5 to Fig. 8. Fig. 5 to Fig. 8 in each case show a cross section. Referring to the embodiment from Fig. 2, this is a cross section along a plane perpendicular to Fig. 2. Referring to the embodiment from Fig. 3 or 4, the cross section shown in Figs. 5 to 8 is made along a circular arch 404 and projected onto a straight line.

[0034] Fig. 5 illustrates the principle of single folding or folding over, as was also used in Fig. 4. An approaching ventilation stream 100 is shown, following axial direction 101. In the position (a), a blade 500 is in the unfolded position, corresponding to a closed position of the valve. By folding over the blade 500 at one of its ends, a fold 501 is produced. During this folding-over, a first part 503 is moved to a position behind a second part 504, so that the first part 503 is shielded from the approaching ventilation stream 101 by the second part 504. In this case, two layers of flexible material 508, 509 which, viewed along the axial direction 100, are stacked on top or behind one another are produced. The transition from position (a) to position (b), and subsequently to position (c), illustrates the opening of the valve. In this case, the fold 501 is displaced along a direction of movement 505 situated in a plane substantially perpendicular to the axial direction 101. In the embodiment from Fig. 5, fold 501 is always situated on the edge 510 of the closed segment 302, 202. By moving the fold 501 along, the surface of the closed segment 302, 202 is reduced during the transition from position (a) to (c). Fig. 5 illustrates that, in the open position of the valve, the size 507 of the closed segment is approximately half the corresponding size 506 in the closed position of the valve. Thus, this way of folding makes it possible to reduce the surface of the closed segment by approximately half for each blade 500 during opening of the valve. It should be noted that in another embodiment, the arrow denoted by 100 may be in the opposite direction, so that the first part 503 is moved to a position for the second part 504.

[0035] Fig. 6 illustrates the principle of double folding. An approaching ventilation stream 100 is shown, moving along axial direction 101. In the position (a), a blade 600 is in the unfolded position, corresponding to a closed position of the valve. In the position (b), the blade is folded in such a way that an S shape is created in the centre of the blade by means of two folds 601 and 602. In this case, a first part 603 is moved to a position behind a second part 604, so that the first part 603 is shielded from the approaching ventilation stream 101 by the second part 604. This creates, viewed along the axial direction 100, three layers of flexible material 608, 609, 610 which are stacked on top of or behind one another, at a central position in the blade. The transition from position (a) to position (b), and subsequently to position (c), illustrates the opening of the valve. In this case, the folds 601, 602 move along a direction of movement 605 situated in a plane substantially perpendicular to the axial direction 101. By moving along the folds 601, 602, the surface of the closed segment 302, 202 is reduced during the transition from position (a) to (c). Fig. 6 illustrates that, in the open position of the valve, the size 607 of the closed segment is approximately a third of the corresponding size 606 in the closed position of the valve. Thus, this way of folding makes it possible to reduce the surface of the closed segment to approximately a third for each blade 600 during opening of the valve. Compared to the principle of single folding in Fig. 5, double folding thus produces a larger passage opening in the completely open position of the valve. It should be noted that in another embodiment, the arrow denoted by 100 may be in the opposite direction, so that the part which is moved to a position for the other part is moved.

[0036] Fig. 7 illustrates yet another folding principle which may be seen as a combination of single and double folding. In the position denoted by (b), a blade 700 is folded over at its end, as in the principle of single folding. This produces a fold 701 which is displaced along a direction of movement 705. In the position denoted by (d), the blade is additionally folded, so that three folds 702, 703, 704 are produced. In this position, there are four layers stacked on top of each other, viewed in the axial direction 100, and the size 707 of the closed segment is approximately one fourth of the size 706 in the closed position of the valve. This thus creates an even larger passage opening in the completely open position of the valve than is the case with the double folding of Fig. 6.

[0037] Fig. 8 illustrates the folding according to the principle of an accordion or Chinese fan. An approaching ventilation stream 100 is shown, following axial direction 101. In position (a), a blade 800 is in the unfolded position, corresponding to a closed position of the valve. Folding takes place by pushing one end of the blade, on the right in the figure, to the other end of the blade, on the left in the figure. This produces several folds 801, 802. As the valve is opened further, from position (a) to (b) to (c), the folds 801, 802 are displaced along a direction of movement parallel to the axial direction 101. Thus, this does not produce any layers which are stacked on top of each other along the axial direction 101. By moving the folds 801, 802, the surface of the closed segment 302, 202 is reduced during the transition from position (a) to (c). Fig. 8 shows that the size 807 is significantly smaller than the corresponding size 806 in the closed position of the valve. This produces a large passage opening in the completely open position of the valve. On the other hand, the folded flexible material takes up a certain space along the axial direction 101, see the size 803 denoted in the figure. In the axial direction, this embodiment is therefore less compact than, for example, the single folding from Fig. 5 or the double folding from Fig. 6.

[0038] Fig. 9 to Fig. 14 show two possible embodiments of a valve. The embodiment from Fig. 9 to Fig. 11 uses the principle of single folding. The embodiment from Fig. 12 to Fig. 14 uses the principle of double folding.

[0039] The embodiment from Fig. 9 to Fig. 11 uses a frame 900, comprising a static portion 902 and a movable element 901. The figure shows a front view on the left and a rear view on the right. In this embodiment, the movable element 901 is a rotor which may be moved according to a rotating movement about a central element 907. The movable element 901 comprises a round ring 905 to which four movable arms 903 are attached. The movable arms 903 are elongated in the radial direction and are distributed symmetrically along the ring 905. The movable arms 903 are fixedly connected to the ring 905, so that the ring 905 and movable arms 903 rotate as a single unit. The static portion 902 comprises a static ring 906 to which four static arms 904 are mounted. The static arms 904 are elongated in the radial direction, and are distributed symmetrically along the static ring 906. In the mounted position of the valve, the static portion 902 is fixedly connected to the surroundings of the valve, for example secured to a tube, wall or ceiling. To this end, the valve may comprise additional fastening components, which are not shown in the figures. The static ring 906 has a central opening 908 which provides space in order to drive the rotor 901 by means of a motor, for example an electrical motor. The opening 908 may be closed completely or a certain degree of air circulation may still be possible. In addition, openings 909 are present, intended for mounting another component, for example an energy generator which provides electricity to the valve. One motor is sufficient to make the four movable arms 903 rotate by driving the ring 905. The static ring 906 and static arms 904 are in a position upstream of the movable ring 905 and movable arms 903. This means that, in the mounted position of the valve, the stator 902 is situated on the side of the approaching flow, whereas the rotor 901 is situated in a more downstream position. In the illustrated embodiment, this is advantageous because any mounted generator is then first situated in the flow. However, in another embodiment, it is possible for the arrow denoted by 101 to be in the opposite direction, so that the rotor 901 is situated on the side of the approaching flow.

[0040] The valve comprises four blades 500. The blades 500 are not illustrated in Fig. 9 or Fig. 10, but are shown in Fig. 11. Fig. 11 shows a front view at the top, in three different positions (a), (b), (c), and a cross section at the bottom, produced along line A-A, B-B, C-C, respectively. The cross sections show that a blade 500 is attached to a movable arm 903 on one side, denoted by 'X', and is attached to a static arm 904 on its other side, denoted by 'Y'. In the illustrated embodiment, a blade 500 is entirely made from a flexible material, for example a flexible type of plastic such as TPE, a fabric or leather. In other possible embodiments, a blade may comprise a local reinforcement made from a rigid material. In other embodiments, a different number of blades is also possible, smaller than or greater than four.

[0041] Fig. 10 and Fig. 11 illustrate the valve in the closed position (a), a semi-open position (b) and the open position (c). In this case, the movable arm 903 denoted by 'X' is rotated by a quarter turn, from a vertical position to a horizontal position. During the simultaneous rotation of the four movable arms 903 and the rotation of the ring 905, the static arms 904 and the static ring 906 remain in a fixed position. As a result thereof, the blades 500 are folded, in accordance with the principle of single folding or folding over, analogously to Fig. 5. Fig. 11 shows that a fold 501 is produced which is displaced in a plane substantially perpendicular to the axial direction, and that two stacked layers are formed in the folded position in the axial direction. The fold 501 is not in contact with the movable element 901. The fold 501 is thus not guided directly by the movable element 901 and can move freely.

[0042] As can be seen in Fig. 11, only the stacked pieces of flexible material take up space, which makes the embodiment very compact. The limited mass of a blade 500 made of flexible material also reduces the energy required to make a blade 500 change position and thus to open or close the valve. During opening or closing, in which process the blade 500 is folded, any dirt or dust which is stuck to the blade is in each case also released. Finally, the blade 500 is made from one piece of material, so that no undesirable gaps are present within a closed segment.

[0043] The embodiment from Fig. 12 to Fig. 14 uses a frame 1200, comprising a static portion 1202 and a movable element 1201. The figure shows a front view on the left and a rear view on the right. In this embodiment, the movable element 1201 is a rotor, which can be moved according to a rotating movement about a central element 1207. The movable element 1201 comprises a round ring 1205 to which four pairs of movable arms 1203, 1233 are attached. There are thus two movable arms 1203 and 1233 for each blade. The movable arms 1203, 1233 are elongated in the radial direction and are distributed symmetrically along the ring 1205. The movable arms 1203, 1233 are fixedly connected to the ring 1205, so that the ring 1205 and movable arms 1203, 1233 rotate as a single unit. The static portion 1202 comprises a static ring 1206 to which four pairs of static arms 1204, 1244 are mounted. There are thus two static arms 1204 and 1244 for each blade. The static arms 1204, 1244 are elongated in the radial direction and they are distributed symmetrically along the static ring 1206. In the mounted position of the valve, the static portion 1202 is fixedly connected to the surroundings of the valve, for example fixed to a tube, wall or ceiling. To this end, the valve may comprise additional fastening components which are not shown in the figures. The static ring 1206 has a central opening 1208 which provides space in order to drive the rotor 1201 by means of a motor, for example an electrical motor. One motor is sufficient to make the four pairs of movable arms 1203, 1233 rotate by driving the ring 1205. The static ring 1206 and static arms 1204, 1244 are in a position upstream of the movable ring 1205 and movable arms 1203, 1233. This means that, in the mounted position of the valve, the stator 1202 is situated on the side of the approaching flow, whereas the rotor 1201 is situated in a more downstream position. However, in another embodiment, it is possible for the arrow denoted by 101 to be in the opposite direction, so that the rotor 1201 is situated on the side of the approaching flow.

[0044] The valve comprises four blades 600. The blades 600 are not illustrated in Fig. 12 or Fig. 13, but are shown in Fig. 14. Fig. 14 shows a front view at the top, in three different positions (a), (b), (c), and a cross section at the bottom, produced along line A-A, B-B, C-C, respectively. The cross sections show that a blade 600 is attached to a movable arm 1203 on one side, denoted by 'X', and is attached to a static arm 1204 on its other side, denoted by 'Y'. The other static arm 1204 helps to keep the blade 600 in position. The other movable arm 1233 consists of two elongate parts, between which the flexible material is situated; the blade is thus retained between the two parts of the arm 1233. In the illustrated embodiment, a blade 600 has a local reinforcement 1400 at the location of the zone between the static arm 1204 and the static arm 1244. In this zone, the blade contains a rigid material. The rest of the blade 600 is made from a flexible material, for example a flexible type of plastic such as TPE, a fabric or leather. In other possible embodiments, a blade may be made entirely from flexible material. In other embodiments, a different number of blades is also possible, smaller than or greater than four.

[0045] Fig. 13 and Fig. 14 show the valve in the closed position (a), a semi-open position (b) and the open position (c). In this case, the movable arm 1203 denoted by 'X' is rotated from a vertical position to an inclined position. During the simultaneous rotation of the four pairs of movable arms 1203, 1233 and the rotation of the ring 1205, the static arms 1204, 1244 and the static ring 1206 remain in a fixed position. Since the blade 600 is gripped at two positions by the movable arm 1203 and by the movable arm 1233, the blade 600 is folded according to an S shape, producing two folds 601 and 602. The blade 600 is thus folded according to the principle of double folding, analogously to Fig. 6. Fig. 14 shows that two folds 601 and 602 are produced, which move in the same direction, in a plane substantially perpendicular to the axial direction. In the axial direction, three stacked layers are formed in the folded position. During their displacement, the folds 601 and 602 are not in contact with the movable element 1201. The folds 601, 602 are thus not guided directly by the movable element 1201 and can move freely. When the completely open position (c) is reached, the blade 600 is folded around the static arm 1244.

[0046] As can be seen in Fig. 14, only the stacked pieces of flexible material take up space in the axial direction, which makes the embodiment very compact. In addition, an even larger passage opening is available here in the open position of the valve than in the embodiment from Fig. 11. The limited mass of a blade 600, largely made of flexible material, also reduces the energy required to change the position of a blade 600 and thus to open or close the valve. During opening or closing, in which process the blade 600 is folded, any dirt or dust which is stuck to the blade is in each case also released. Finally, the blade 600 is made from one piece of material, so that no undesirable gaps are present within a closed segment.

[0047] Although the present invention has been illustrated by means of specific embodiments, it will be clear to the person skilled in the art that the invention is not limited to the details of the above illustrative embodiments, and that the present invention may be carried out with various changes and modifications without departing from the area of application of the invention. Therefore, the present embodiments have to be seen as being illustrative and not as being restrictive in any respects, with the area of application of the invention being described by the attached claims and not by the above description, and any changes which fall within the meaning and the scope of the claims are therefore deemed to be incorporated herein. In other words, it is assumed that this covers all changes, variations or equivalents which fall within the area of application of the underlying basic principles and the essential attributes of which are claimed by this patent application. In addition, the reader of this patent application will understand that the words "comprising" or "comprise" do not exclude other elements or steps, that the word "a(n)" does not exclude the plural. Any references in the claims should not be interpreted as a limitation of the claims in question. The terms "first", "second", "third", "a", "b", "c" and the like, when used in the description or in the claims, are used to distinguish between similar elements or steps and do not necessarily describe a sequential or chronological order. In the same way, the terms "top side", "bottom side", "over", "under" and the like are used for the purpose of the description and these do not necessarily refer to relative positions. It should be understood that these terms are interchangeable under the appropriate circumstances and that embodiments of the invention are able to function according to the present invention in other orders or orientations than those described or illustrated above.

Claims

1. Valve for controlling a ventilation stream (100) through an opening (102), wherein said opening (102) is delimited by an edge (201, 301) and has a central axis in the axial direction (101), said valve comprising:

- a frame (900, 1200) comprising a static portion (902, 1202) adapted to mount said valve;

- at least one blade (500, 600) which is connected to said frame (900, 1200), such that in mounted condition of said valve, said blade (500, 600) is movable along said edge (201, 301), wherein a segment (202, 302) of said opening (102) is closed to said ventilation stream (100) by means of said blade (500, 600),

characterized in that:

said blade (500, 600) comprises a flexible material, and

said frame (900, 1200) comprises a movable element (901, 1201) adapted to fold said flexible material in such a way that the surface of said closed segment (202, 302) is changed.

2. Valve according to one of the preceding claims,
wherein said movable element (901, 1201) is adapted to fold said flexible material in such a way that, at least for certain opening positions of said valve, multiple layers (508, 509; 608, 609, 610) of said flexible material are present in said axial direction (101), over at least a portion of said segment (202, 302).

3. Valve according to one of the preceding claims,

wherein said movable element (901, 1201) is adapted to, during said folding, move a first part (503, 603) of said flexible material to a position behind a second part (504, 604) of said flexible material, wherein in said position, said first part (503, 603) is shielded from said approaching ventilation stream (100) by said second part (504, 604),

or to a position in front of said second part, wherein in said position, said first part is situated on the side of said approaching ventilation stream (100).

4. Valve according to one of the preceding claims,
wherein said movable element (901, 1201) is adapted to displace one or more folds (501, 601, 602) in said flexible material during said folding, along a direction of movement situated in a plane substantially perpendicular to said axial direction (101).

5. Valve according to Claim 4,
wherein said one or more folds (501, 601, 602) are not in contact with said movable element (901, 1201) during displacement of said one or more folds (501, 601, 602).

6. Valve according to Claim 2,
wherein said movable element (901) is adapted to move one fold (501) situated on an edge (510) of said segment (202, 302), and two of said layers (508, 509) are present.

7. Valve according to Claim 2,
wherein said movable element (1201) is adapted to move two folds (601, 602), and three of said layers (608, 609, 610) are present.

8. Valve according to Claim 7,
wherein said movable element (1201) is adapted to move two folds (601, 602), so that said folds (601, 602) move simultaneously and in the same direction.

9. Valve according to one of the preceding claims,
wherein said flexible material comprises a fabric material and/or a flexible type of plastic.

10. Valve according to one of the preceding claims,
wherein said blade (600) comprises a rigid material positioned at one or more edges of said blade (600), and wherein said rigid material adjoins said flexible material.

11. Valve according to one of the preceding claims,
wherein said blade (500, 600) is attached to said static portion (902, 1202) at at least one position and is attached to said movable element (901, 1201) at at least one other position.

12. Valve according to one of the preceding claims,
wherein said valve is adapted to move said movable element (901, 1201) according to a rotating movement.

13. Valve according to Claim 12,

wherein said static portion (902, 1202) comprises one or more static arms (904, 1204, 1244) which are elongated in the radial direction, and said movable element (901, 1201) comprises one or more movable arms (903, 1203, 1233) which are elongated in the radial direction,

and wherein said valve is adapted to rotate said one or more movable arms (903, 1203, 1233) about a central point (907, 1207).

14. Valve according to Claim 13,
wherein said valve comprises one static arm (904) and one movable arm (903) for each said blade (500, 600), or two static arms (1204, 1244) and two movable arms (1203, 1233).

15. Valve according to one of the preceding claims,
wherein said valve comprises multiple blades (500, 600), preferably four blades (500, 600).

Drawing