Slide valve for a ventilation device

Abstract

The present invention relates to a valve device (1) for a ventilation installation. The valve device (1) comprises a vent surface (4) that is equipped with a plurality of vent apertures (5) and a slide valve (6) comprising a slide valve plate (7) equipped with a plurality of slide valve apertures (8). The valve plate formed such that it can be varied between taking a first position (I) at which the vent apertures (5) are covered by the slide valve plate (7), and taking a second position (II) at which at least some vent apertures (5) have surfaces that overlap with some slide valve apertures (8) such that an air flow is permitted through the valve device (1). The valve device (1) is designed such that when the slide valve plate (7) is positioned on that side of the vent surface (4) that normally has a relatively higher pressure, the high pressure side (9), than the other side, the low pressure side (10). The slide valve plate (7) is formed such that the force from the pressure difference between the high pressure side (9) and the low pressure side (10) is sufficient to retain the slide valve plate in its place at the vent surface (4) when it is in the first, closed position (I).

Description

TECHNICAL FIELD

[0001] The present invention relates to a valve device and a slide valve for a ventilation installation.

BACKGROUND

[0002] During ventilation fresh air is in many cases supplied via supply air diffusors, it may be one or more that are connected to a main pipe, where supplied fresh air is brought into motion towards the supply air diffusors via the main pipe by means of a fan arrangement. A supply air diffusor may in its least complicated form be an opening or aperture in the ventilation system. The supply air diffusor may also be integrated with a cooling or heating baffle to be able to control the temperature of the supplied air. The supply air diffusor may in these cases be arranged such that the fresh air that is supplied to the room brings existing air in the room such that is passes a heat exchanger in a cooling/heating baffle and is tempered.

[0003] It is sometimes desirable to control the flow of supplied air in dependence of the present need. For example, a conference room may sometimes be empty, and sometimes be more or less occupied, such that different needs of air supply arise. To be able to control how much air that is released in the different supply air diffusors, the ventilation arrangement is often supplied with a plurality of slide valves or vents in, or in close connection to, the supply air diffusors.

[0004] An important function of the slide valves is that they shall be able to close tight when it is not desired to have any flow in a duct. Leakage leads to unnecessary ventilation and thus energy waste. Leakage may also lead to the occurrence of undesired noise in the form of howling or whining vents. In order to be able to provide ventilation device or slide valves that close tightly is previously known and is used in such installations today. It is, however, desirable to develop a siding vent with an uncomplicated and reliable design.

[0005] There is therefore a desire for a valve device or slide valve ventilation device that fulfills the above requirements.

DISCLOSURE OF THE INVENTION

[0006] The object of the present invention is to provide a slide valve and a valve device in a ventilation installation that is easy to install in a ventilation installation and that can be adjusted by relatively uncomplicated means.

[0007] The present invention thus relates to a valve device and a slide valve for a ventilation installation. The ventilation installation contains one or more ducts that may contain one or more valve devices. The valve device comprises a vent surface that is equipped with a plurality of vent apertures for passage of air in the duct and a slide valve comprising a slide valve plate equipped with a plurality of slide valve apertures enabling control of the air permeability in the duct by varying its position in relation to the vent surface. The slide valve is thus formed such that it may take a first position (I) in which the slide valve is positioned on the vent surface such that the vent apertures are covered by the slide valve such that the valve device is closed and no air flow is permitted through the valve device. The slide valve may then be moved relative the vent surface and take a second position (II) at which at least some vent apertures have surfaces that overlap with some slide valve apertures such that an air flow is permitted through the valve device. In the second position, the apertures in the slide valve and the vent surface, respectively, may be positioned such that apertures are placed straight over each other corresponding to a completely open position or placed such that the apertures only partly overlap each other corresponding to a partly open position (or partly closed position).

[0008] The slide valve and the valve device according to the present invention are designed such that when the slide valve is in the first closed position, is sucked fixed and closes tightly against the vent surface without any further detail that fixes the slide valve being required. The slide valve is thus positioned on that side of the vent surface that normally has a higher pressure, the high pressure side, than the other side, the low pressure side, such that the pressure difference between the two sides of the slide valve ensures that the slide valve is tight along the vent surface such that no air passage through the ventilation device is permitted.

[0009] In order to enable the slide valve to have such a function and to function in an efficient manner as a slide valve, it is necessary that the slide valve plate is sufficiently soft and flexible such that it closes tight, at the same time as it is sufficiently rigid enough to be brought there and back without folding or squinting. An optimization of these properties is thus required. If it is the case that the suction force is the force that holds the slide valve in place, the slide valve shall have a relatively low weight since it usually are low pressure differences on the different sides of the vent surface. The slide valve plate is thus preferably designed with respect to its weight and flexibility such that the force from a pressure difference between the high pressure side and the low pressure side is enough to keep the slide valve plate in its position when it is located on the high pressure side of the vent even though it is located on the underside of the vent, i.e. if the plate and the valve are located such that their surfaces are horizontally located and the slide valve plate is located on the surface side of the valve facing towards the ground. The force of the pressure difference which influences the slide valve plate should thus be greater than the gravity influencing the slide valve plate. In addition to above mentioned properties are there of course several other parameters which influence how the slide valve plate is sucked to stick to the vent, e.g. the surface structure of the vent surface and the slide valve plate and the size and quantity of holes and their location in the vent surface and the slide valve plate.

[0010] The force that is described above is of course also present at other valve devices where the slide valve is placed on the side of the cent surface that has a relatively higher pressure. In this case, however, the slide valve is designed in such a way that the force that arises due to the pressure difference between the low pressure and high pressure side constitutes the essential force to retain the slide valve in place. This brings that the slice valve in itself must be relatively light in order to avoid a too large affection by the gravity force.

[0011] It is obvious that the valve device is assumed to comprise some kind of rail or other arrangement having the function of preventing the slide valve plate from being completely detached from the vent surface when the slide valve is in its open position It should however be noted there is a huge difference in the design of the slide valve and the slide valve plate in case the slide valve plate shall be mechanically pressed towards the vent surface in order to ensure that the slide valve is tight which is the normal way of designing valves in different kinds of arrangements. In such valve arrangements is there in general a need for a larger force in order to move the slide valve plate which also implies a need for an increased rigidity of the slide valve plate while the need for a low weight not is particularly relevant. Such a design of a slide valve will thus imply other needs which will influence the design of the slide valve.

[0012] The valve device of the present invention can for example be formed such that the suction force from a predetermined pressure difference, for example 100 Pascal (Pa) between high pressure side and low pressure side, exceeds the gravitational force from the slide valve when the slide valve is in the first closed position, i.e. that the slide valve would remain even if it is turned upside down. Preferably the slide valve is designed such that a pressure difference of 70 Pa is sufficient, and even more preferably, that a pressure difference of 40 Pa provides a retaining effect which exceeds the gravitational force from the slide valve. By performing a test at which the slide valve is placed such that it is dragged straight away from the vent surface by the gravitational force, i.e. that the slide valve is placed on the lower side of the vent surface and that the slide valve and the vent surface are horizontally placed while the force from the pressure difference acts in the opposite direction, one may determine whether the sucking force is sufficiently large to retain the slide valve. Since there are a wide variety of parameters as pointed out above (e.g. weight, size or geometry of the holes, flexibility, surface structure etc.) which may be varied in order to influence the property of the slide valve plate to be sucked and stuck to the vent surface is it difficult, if not to say impossible, to define certain values for single parameters which must be satisfied in order to be able to design a slide valve according to the above stated specifications, e.g. being able to stay in its position when there is a pressure difference of 100 Pa. The feature which most probably differs from commonly used slide valve plates today in similar devices is probably the weight of the slide valve which is lower for most of the similar slide valves. Except the weight of the slide valve and the pressure difference between the two sides, naturally other factors such as the aperture area affect how large force from the pressure difference that works on the slide valve. When the slide valve is placed such that by means of gravitational force is pressed against the vent surface, gravitational and suction force will of course co-operate. Using a relatively thin and light slide valve enables the slide valve to easily and by means of a relatively small force shift between the first, closed position (I) and the second, open position (II), i.e. it is relatively unaffected by gravitational forces which either can contribute to leakage of the slide valve if it counteracts and overcomes the suction force, or to an unnecessary high friction if the gravitational force co-operate with the suction force. The slide valve plate is therefore relatively thin and may have a thickness that falls below 1 mm, preferably below 0,7 mm and most preferably even below 0,5 and is expected to be between 0,15 and 0,35 mm. The thickness of the slide valve plate is of course dependent of the material it is made of. A suitable choice of material is plastic or similar polymer. The plate could be laminated by several different types of plastic or other materials, but it is probably easiest to use the same material all along from am manufacturing point of view. There is also no risk that the layers loosen or that different material age differently and give rise to deformations as a consequence of different material properties. Letting the slide valve plate be made in a homogenous piece of material thus have some advantages if a material may fulfill the desired criteria. The material shall thus be chosen such that the slide valve plate is sufficiently stiff and be able to slide easily against the vent surface enabling it to be easily pushed or in any other way change position from the first position (I) to the second position (II) and close sufficiently tightly when the slide valve plate is in the first, closed position (I). The material chosen for the plate can therefore be a polyester film, for example Mylar.RTM. A that is one from DuPont that suitably can be used in thicknesses from 0,15 to 0,50 mm. The material that is used suitably has a Young's modulus that exceeds 2000 MPa according to the test method ASTM D 882 since too soft materials have a tendency to fold. It is essential that the slide valve has such a stiffness relative the friction that arises when the slide valve is pushed, that it does not fold or bend to any essential degree, at the same time as it is not stiff to such a degree that it lack the ability to adapt to the bedding. The slide valve plate, with its recessed apertures, thus has to present a sufficient bending rigidity. The bending rigidity thus partly depends on material and thickness, but also on the aperture configuration. It is also important that the surface does not stick, i.e. the properties of the slide valve material shall not be of such character that it has a too large tendency to stick at the surface. The surface property of the material thus becomes a compromise between finding a material for the slide valve that closes sufficiently tightly at the same time as it does not stick too hard to the surface. In practice, it may facilitate that a slide valve that has been closed is pulled instead of pushed in order to avoid that it sticks to the surface, avoiding that the slide valve folds. A material that is stable with respect to form contributes to avoid folding, where stable with respect to form comprises stability regarding for example ageing, such as wear, and environment, such as temperature.

[0013] The valve device is thus preferably formed such that the slide valve is pressed in place and retained against the vent surface only by means of the pressure difference between the low pressure side and the high pressure side. This leads to that no extra devices are needed for retaining the plate which makes the design of the valve device less complicated. It also leads to that the mechanism that is used to change the slide valve's position from open to close and vice versa may be made in a less complicated way when it does not have to be used to overcome other added frictional forces that press the slide valve against the vent surface.

[0014] The valve device may be formed such that the change of the slide valve's position from first, closed position (I) to the second, open position (II) is executed by pulling the slide valve by means of a drawing arm attached to the front part of the slide valve, i.e. the end of the slide valve that lies foremost in the direction of movement when the slide valve is opened. When the position of the slide valve is changed from the second, open position (II) to the first, closed position (I), it is thus pushed by means of the drawing arm attached to the end that lies rearmost in the direction of movement. It may be advantageous to have the slide valve arranged in this manner since the largest forces probably are needed to loosen the slide valve when it has been it its closed position and has been sucked to the vent surface. By means of this arrangement it is avoided that the slide valve plate is bent or folded when it is released from the closed position (I). Folding of he slide valve plate can also be avoided if the drawing arrangement is attached to both ends, for example by letting the drawing arm being attached to a stiffened part that either may be integrated with the slide valve plate or a separate thin rod that runs along the drawing direction of the slide valve plate from the front part to the rear part of the slide valve plate and is attached to both ends. It is also possible to let one drawing arm or two separate drawing arms being attached to the front and rear end of the slide valve plate such that the may be used to mainly pull the end that is positioned foremost in the movement of direction during movement of the grid.

[0015] The slide valve plate is preferably formed such that its aperture geometry corresponds to the vent apertures of the vent surface. It may of course be conceivable that there are some apertures in the vent surface that do not have any corresponding apertures in the slide valve plate when the slide valve plate is in the open position to contribute to holding the slide valve plate in place in the open position. Even if further detail and devices are necessary for pressing the slide valve plate against the vent surface, any kind of guiding rails or other guiding devices may be useful to straighten the plate.

[0016] The valve device may really only be arranged to function in two different positions, i.e. to control the slide valve to shift between the first, closed position (I) and the second, open position (II) at which essentially all apertures are completely open, i.e. all apertures in the slide valve plate have corresponding apertures in the vent surface while there, as described above, still may be apertures in the vent surface that abuts the slide valve plate to keep the slide valve plate in place.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will now be described more in detail with reference to the appended drawings, where:

[0018] FIG. 1 shows a schematic overview of a ventilation device;

[0019] FIG. 2 shows a valve device with a slide valve in a first, closed position (I);

[0020] FIG. 3 shows a valve device with a slide valve in a second, open position (I);

[0021] FIG. 4 shows a valve device in a partially closed position.

DETAILED DESCRIPTION

[0022] FIG. 1 shows a schematic view of a piece of ventilation installation 2 with a valve device 1 comprised in a supply air diffusor 11 at the end of a duct 3. The figure thus shows a very simple ventilation installation 2 and it is possible to add more supply air diffusors 11 and ducts to the installation 2. The ventilation arrangement is shown viewed from below. The duct 3 is connected to a fan 12 that is used to create an air flow by sucking in fresh air 13 and distributes in the duct such that a high pressure side 9 is created in the duct that has a higher pressure than what is present in the surrounding air outside the duct, the low pressure side 10. The valve device 1 comprises a vent surface 4 in the duct 3 which has been made by making a plurality of vent apertures 5 for passage of air in the duct 3 such that a supply air diffusor 11 has been created. The vent surface 4 is intended to co-operate with a slide valve 6 (see FIG. 2) which is attached to a drawing arm 14.

[0023] FIG. 2 shows a slide valve 6 comprising a slide valve plate 7 equipped with a plurality of slide valve apertures 8 when the slide valve is in its first, closed position (I). The slide valve plate 7 is formed such that it may be varied between taking first position (I) at which the slide valve 6 is position on the vent surface 4 such that the vent apertures 5 are covered by the slide valve plate 7 and no flow is permitted through the valve device 1. The slide valve 6 may then be adjusted by means of the drawing arm 14 and to take a second position (II) at which at least some vent apertures 5 have surfaces that overlap with some slide valve apertures 8 such that an air flow is permitted through the valve device 1 as shown in FIGS. 3 and 4. In the second position, the apertures in the slide valve and the vent surface, respectively, may be positioned such that apertures are placed straight over each other corresponding to a completely open position or placed such that the apertures only partly overlap each other corresponding to a partly open position (or partly closed position). It is thus possible to let the slide valve 6 take different second position (II) where different amounts of air are permitted to pass the valve device 1 by adjusting how large part of the slide valve apertures 8 that overlap with the vent apertures 5 such that the flow through the supply air diffusor 11 is controlled. The valve device 1 is designed such that the slide valve (6) is positioned on that side of the vent surface 4 that normally has a relatively higher pressure, the high pressure side (9), than the other side, the low pressure side 10. The high pressure side 9 corresponds to the side of the vent surface 4 that faces the duct 3 and the low pressure side corresponds to the side that faces away from the duct 3 and in this case is constituted by surrounding air. The slide valve plate 7 will then be exposed to a force from the pressure difference between the high pressure side 9 and the low pressure side 10 such that it is pressed or sucked against the vent surface 4. The force that strives against pulling the slide valve 6 against the vent surface 4 is largest when the slide valve is closed as shown in FIG. 2, and smallest when the slide valve is completely open as shown in FIG. 3. The slide valve 6 is formed such that when the slide valve 6 is positioned in the closed position, the force from the pressure difference between the high pressure side 9 and the low pressure side 10 sufficiently large to retain the slide valve 6 in the closed position and ensure that the slide valve 6 is tight along the vent surface such that no air flow is permitted.

[0024] The vent apertures 5 and the slide valve apertures 8 may of course be modified regarding size, shape and mutual placement. For example, it may be possible to add some extra vent apertures 5 to the vent surface 4, which extra vent apertures 5 are covered by the slide valve plate 7 even when the slide valve is in the open position (II) such that the plate is better held in place in the open position (II). Even if it is not necessary with any extra arrangement for pressing the slide valve plate 7 against the vent surface 4 in order to retain the slide valve 6 against the vent surface 4, it may be useful to have any kind of guiding rails or similar devices to guide the slide valve 7 when it is brought between its different positions such that it does not squint and gets out of position.

Claims

1-12. (canceled)

13. A valve device for a ventilation installation comprising at least one duct, where the valve device comprises a vent surface that is equipped with a plurality of vent apertures for passage of air in the duct, and a slide valve comprising a slide valve plate equipped with a plurality of slide valve apertures, said slide valve plate formed such that it can be varied between taking a first position (I) at which the slide valve is positioned on the vent surface such that the vent apertures are covered by the slide valve plate such that the valve device is closed and no flow is permitted through the valve device, and taking a second position (II) at which at least some vent apertures have surfaces that overlap with some slide valve apertures such that an air flow is permitted through the valve device and the valve device is designed such that the slide valve plate is positioned on that side of the vent surface that normally has a higher pressure, the high pressure side, than the other side, the low pressure side, wherein the slide valve plate is designed with respect to a weight and flexibility of the slide valve plate such that the force from the pressure difference of 100 Pascal between the high pressure side and the low pressure side is sufficient to retain the slide valve plate in its place at the vent surface when it is in the first, closed position (I) even if the slide valve plate is turned upside down.

14. The valve device according to claim 13, wherein the slide valve plate has a thickness that falls below 1 mm, preferably below 0,7 mm and most preferably below 0,5 mm.

15. The valve device according to claim 13, wherein the slide valve plate is made in a plastic material or a polymer.

16. The valve device according to claim 13, wherein the slide valve plate has a Young's modulus that exceeds 2000 MPa.

17. The valve device according to claim 13, wherein the slide valve plate is made in a homogenous piece of material.

18. The valve device according to claim 13, wherein the slide valve plate is held in place against the vent surface only by the force from the pressure difference between the high pressure side and the low pressure side when the slide valve is in the first, closed position (I).

19. The valve device according to claim 13, wherein the size and relative placement of the slide valve apertures of the slide valve plate corresponds to the vent apertures of the vent surface.

20. The valve device according to claim 13, wherein the change of the valve device's position from first, closed position (I) to the second, open position (II) is executed by pulling the slide valve by means of a drawing arm attached to the front part of the slide valve plate, and that when the position of the slide valve is changed from the second, open position (II) to the first, closed position (I), is thus pushed by means of the drawing arm.

21. The valve device according to claim 13, wherein the valve device is arranged to control the slide valve to shift between the two positions defined above, i.e. the first, closed position (I) and the second, open position (II), where the second, open position corresponds to that the valve device is completely open.

22. The valve device according to claim 20, wherein the drawing arm is attached to both the front and rear part of the slide valve plate.

23. The valve device according to claim 20, wherein the drawing arm is attached to a stiffened part that runs along the drawing direction of the slide valve plate from the front part to the rear part of the slide valve plate, for example a thin rod that runs over the whole slide valve and is attached to both ends.