Arrangement for volume flow control in a fluid channel

Abstract

Arrangement for volume flow regulation in a fluid channel, wherein the arrangement comprises a channel (1) and at least one closure element (2) arranged in the channel (1), wherein the closure element (2) comprises at least one pair of flaps (3, 3') which is pivotably mounted on or in the fluid flow direction through the channel (1) behind a web (4) extending through the channel cross-section between an open position, in which it at least partially releases the channel cross-section, and a closed position, in which it closes the channel (1), wherein the web (4) or the channel (1) comprises at least one first magnetic element (5), wherein the flaps of the pair of flaps (3, 3') each comprise at least one second magnetic element (6) which is magnetically coupled to the first magnetic element (5), characterized in thatthat the distance of the at least one first magnetic element (5) to the pivot axis (x) is less than one fifth of a dimension of the flaps (3, 3') perpendicular to the pivot axis (x), wherein the distance is preferably less than one tenth of the dimension of the flaps (3, 3').

Description

[0001] The invention relates to an arrangement for the volume flow regulation in a fluid channel with the features of the preamble of claim 1.

[0002] German patent DE 20 2010 003 340 U1 discloses a ventilation flap for closing an air duct, ventilation pipe, or the like, to which fans or other ventilation devices can be connected. A magnet on the flap housing is intended to securely close the flap and prevent unintentional opening and noise generation when there is no airflow generated by ventilation devices or the like. The described device has the disadvantage that it is only suitable for single flap closures and, moreover, requires a comparatively high flap opening pressure to move the flap from the closed position when an airflow begins.

[0003] Furthermore, EP 2 597 391 A1 discloses a wall box in which a cover is linearly adjustable relative to a guide tube between an open and a closed position. In the closed position, the cover closes a ventilation opening of the guide tube and is held in this position by magnets, so that the cover only moves out of the closed position when there is an internal tube pressure exceeding the holding force of the magnets.

[0004] In closure arrangements where the closure element is formed from a pair of flaps, as described in DE 10 2014 113 210 A1, it is provided that the two flaps of the flap pair are pre-tensioned into the closed position by means of a torsion spring, so that when the volume flow begins, the flaps must be pre-tensioned against the progressive characteristic curve of the torsion spring, which results in a corresponding pressure loss in the channel.

[0005] Other locking arrangements are known, for example, from DE 691 04 267 T2, US 5 245 956 A, DE 10 2005 012 184 B4, EP 1 865 167 A1, US 2 981 172 A, DE 199 19 701 A1, DE 41 31 153 C1, GB 2 167 852 A or US 6 676 508 B1.

[0006] It is therefore the object of the invention to propose an arrangement of the type described above which enables reliable volume flow control in a fluid channel.

[0007] This problem is solved according to the invention by an arrangement having the features of claim 1. The dependent claims each relate to advantageous embodiments of the invention.

[0008] Accordingly, the distance of the at least one first magnetic element to the pivot axis (x) is less than one-fifth of a dimension of the flaps perpendicular to the pivot axis, preferably less than one-tenth of the dimension of the flaps. The first and second magnetic elements can be, for example, a permanent magnet, a paramagnet, or an electromagnet, in particular an electromagnet with adjustable magnetic field strength. They can have a natural magnetic moment or an induced magnetic moment. For example, one of the two magnetic elements can be a permanent magnet or an electromagnet, and the other a paramagnet that only acquires a magnetic dipole moment upon inductive interaction with the first magnetic element.

[0009] The attractive force between the magnetic elements, and consequently the closing torque acting on the flaps, is at its maximum when the flaps are closed, as the magnetic elements are at their closest point in this position. Opening the flaps increases the distance between the first and second magnetic elements, resulting in a sharp, non-linear decrease in the magnetic force and thus also in the closing torque. This effect is amplified by the fact that opening the flaps changes the orientation of the first and second magnetic elements relative to each other. For example, the orientation of the magnetic elements can change from parallel in the closed position to perpendicular in the open position.

[0010] Another effect is that when the flap is open, the distance between the magnetic force line and the flap's axis of rotation decreases. This leads to a further reduction in the closing torque. Therefore, by appropriately selecting various parameters such as magnet type, magnet strength, initial distance, and the permeability of the medium between the magnets, virtually any desired characteristic curve for the flap closing torque can be achieved.

[0011] By adjusting the desired magnet parameters, the required opening pressure can be individually adapted to the installation conditions (compensating for dynamic pressure differences; compensating for structurally induced channel inclination). Therefore, variable parameter settings may be necessary. An automatic adjustment to compensate for pressure dynamics is also conceivable (for example, via an electromagnet).

[0012] A fluid within the meaning of the invention can in particular be a gas, a liquid, or a gas-liquid mixture. The described arrangement is particularly suitable for regulating the volume flow of an exhaust air duct, for example, for the removal of fumes from a range hood.

[0013] It may be provided that the first and second magnetic elements are arranged in such a way that they overlap at least partially in the closed position.

[0014] Furthermore, the first and second magnetic elements can assume a minimum distance in the closed position, whereby the second magnetic element is guided on a circular path around the pivot axis when the locking element is pivoted from the closed position to the open position, so that the second magnetic element has a maximum distance to the first magnetic element in the open position.

[0015] If the channel has at least one first magnetic element, this element can be arranged on the inner or outer circumference of the channel. If the first magnetic element is arranged on the outer circumference of the channel, a pivot axis of at least one flap of the flap pair can be guided through a wall of the channel, with the pivot axis connected to the second magnetic element at a distance outside the outer circumference of the channel. In this configuration, the entire magnetic assembly, consisting of the first and second magnetic elements, is located outside the inner cross-section of the pipe, further reducing the pressure loss caused by the closure element. In this case, the second flap, whose axis is not guided to the outer circumference, would be movably coupled to the first flap. A preferred implementation could be achieved via a toothed connection between the two axes.

[0016] The preferred cross-sectional shape is circular, although an oval, square or rectangular cross-section is also possible.

[0017] By reducing the distance to the axis of rotation, the closing torque can be reduced. Therefore, an embodiment with variable adjustment of the closing torque via the axis distance is also conceivable. In one embodiment, this can be achieved using magnetic elements mounted in movable carriages.

[0018] The bridge can have at least one first magnetic element on opposite sides, spaced apart from the pivot axis, with each flap of the flap pair having at least one of the second magnetic elements. The first magnetic elements arranged on opposite sides of the bridge, spaced apart from the pivot axis, can be further spaced apart from each other in the longitudinal direction of the bridge, preferably vertically spaced from each other.

[0019] The two flaps of the flap pair can be pivoted about a common pivot axis or about separate, parallel-spaced pivot axes.

[0020] The bridge or channel can have a stop against which at least one of the flaps of the flap pair rests in the open position, so that the first and second magnetic elements are arranged at a predetermined distance from each other in the open position. The stop can, for example, be located on the inner circumference of the channel.

[0021] It may further be provided that the first and the second magnetic element each have a magnetic element with a magnetic field orientation, wherein the two magnetic field orientations are essentially parallel to each other in the closed position, so that the magnetic field orientations in the open position enclose an angle corresponding to an adjustment angle from the closed position to the open position.

[0022] Furthermore, the web can have a fluid-dynamically optimized contour on a first longitudinal side, which is exposed to fluid flow, with the pivot axis about which the flaps can be pivoted being located on a second longitudinal side opposite the first longitudinal side, lying in the flow shadow of the web.

[0023] If the first and / or second magnetic elements are designed as electromagnets, this allows for adjusting the restoring torque of the valves in the valve pair and thus regulating the volume flow through the duct. Determining the volume flow then only requires measuring the magnetic force and determining the difference between the duct pressure upstream and downstream of the closure element. From the magnetic force, the opening angle and thus the pressure loss coefficient (zeta value) of the valves can be determined. Using a previously recorded calibration curve, control electronics can then calculate the volume flow in the pipeline from the zeta value of the valves and the pressure difference upstream and downstream of the closure element, and regulate it accordingly by changing the magnetic force. The electrical leads for controlling the electromagnets can be routed through the web.

[0024] It can therefore be provided that at least the first magnetic element has an electromagnet with adjustable magnetic field strength, the arrangement further comprising a measuring and control unit which determines the volume flow through the channel depending on a magnetic attraction force between the first and the second electromagnet and a pressure loss caused by the closure element.

[0025] Furthermore, the measuring and control unit can be designed to adjust the magnetic attraction force, and thus the angle of the flaps, by varying the magnetic field strength, so that a predetermined volume flow rate is achieved for a given pressure loss. In addition, the measuring and control unit can be designed to determine a pressure loss by calculating the difference between a first fluid pressure upstream of the closure element and a fluid pressure downstream of the closure element. The measuring and control unit can have its own database or access a database containing device characteristics that relate the electromagnet's control current and a measured pressure loss to the resulting volume flow rate.

[0026] Further details of the invention are explained with reference to the figures below. These show: Fig. 1 in schematic representation an embodiment of a locking element according to the invention in the closed position of the flaps; Fig. 2 in schematic representation the embodiment according to Fig. 1, wherein one of the flaps is arranged in the open position and the other in the closed position; Fig. 3 in schematic representation an embodiment of the arrangement according to the invention; and Fig. 4 in schematic representation a third embodiment of the arrangement according to the invention.

[0027] In the Fig. 1 and Fig. Figure 2 schematically shows the essential locking element 2 for realizing an arrangement according to the invention. The locking element 2 essentially consists of a pair of flaps 3, 3' which pivot about a common axis x from the Fig. The flaps 3 and 3' can be folded towards each other in the closed position shown in Figure 1 and then folded into an open position. Instead of a common pivot axis x, the flaps 3 and 3' can also be mounted via separate pivot axes spaced parallel to each other.

[0028] The pivot axis x is arranged immediately downstream of the web 4 in the fluid flow direction indicated by the arrow. The pivot axis x can be formed directly on the web 4 or independently of it at a distance, as shown in Fig. 1 and Fig. Figure 2 shows the pivot axis x located in the lee of the pier 4. The pier 4 has two first magnetic elements 5, each of which is associated with one of the second elements 6. The first and second elements 5, 6 are arranged at a distance from the pivot axis x. This distance of the first and second elements 5, 6 from the pivot axis x is dimensioned such that it is much smaller than a dimension of the flaps 3, 3' perpendicular to the pivot axis x. For example, the distance of the elements 5, 6 from the pivot axis x can be less than one-fifth of the dimension of the flaps 3, 3' perpendicular to the pivot axis x.

[0029] To avoid mutual interference between the magnet pairs 5, 6, the magnet pairs 5, 6 can be offset, for example, arranged at opposite ends of the bridge 4.

[0030] The attractive force of the magnetic elements 5, 6 produces the maximum closing torque when flaps 3, 3' are closed, as the elements 5, 6 are at their smallest distance from each other in this position. Opening the flaps 3, 3' increases the distance between the elements 5, 6, leading to a sharp, non-linear decrease in the magnetic attraction force and thus also in the closing torque. This effect is further amplified by the fact that opening the flaps 3, 3' changes the orientation of the magnetic elements 5, 6, for example, from parallel to perpendicular. Another effect is that when flaps 3, 3' are open, the distance of the line of action of the magnetic attraction force (in Fig. 2 (indicated by the dashed lines passing through the magnet pairs 5, 6) to the pivot axis x of the flaps 3, 3' is reduced. This leads to a further reduction of the closing torque. Thus, by appropriately selecting the magnet type, magnet strength, initial distance in the closed position, permeability of the medium between the magnets, etc., almost any desired characteristic curve of the flap closing torque can be achieved.

[0031] In particular, the closing torque in the illustrated embodiment, when flap 3, 3' is wide open, is many times smaller than in a comparable backflow preventer from the prior art, where the flaps are pre-tensioned by a torsion spring with an identical initial closing torque. Therefore, with the same volume flow rate, the closing element 2 of the arrangement according to the invention opens significantly wider than in a conventional, spring-operated backflow preventer. In contrast to the progressive characteristic curve of a torsion spring, the described magnetic drive of the flaps exhibits a degressive characteristic curve.

[0032] The bridge 4 can also have the function of providing a stop 7 against which the flaps 3, 3' rest in the open position of the locking element 2 and thus assume a defined orientation.

[0033] At the in Fig. In the embodiment shown in Figure 3, the web 4 has a fluid-dynamically optimized contour 8 on the longitudinal side which is exposed to the volume flow, so that the first magnetic elements 5 and the second magnetic elements 6 are arranged in the lee of the web 4.

[0034] The first magnetic elements 5 are designed as electromagnets that can be controlled via a measuring and control unit 9. For this purpose, the measuring and control unit 9 is electrically connected to the first electromagnets 5 via a power line 13, which is guided through a cable duct extending longitudinally along the web 4. Furthermore, the measuring and control unit 9 is designed to determine the pressure difference caused by the closure element 2. For this purpose, a pressure sensor 12 is arranged both upstream and downstream of the closure element 2 in the direction of fluid flow, and each sensor outputs a corresponding pressure signal to the measuring and control unit 9.Alternatively, the pressure sensors can also be part of the measuring and control unit 9, in which case the measuring and control unit 9 has two pressure lines 10, one of which measures the channel pressure in the fluid flow direction upstream of the closure element 2 and the other of which measures the channel pressure in the fluid flow direction downstream of the closure element 2.

[0035] The Fig. Figure 4 shows an embodiment in which the first and second magnetic elements 5, 6 are arranged outside the inner cross-section of the channel 1 and form part of a measuring and control unit 9, which is arranged on the outer circumference of the channel. For example, the pivot axis x of the flaps 3, 3' can be provided by passing through a rotary feedthrough through the outer circumference of the channel 1 into the measuring and control unit 9, wherein the second magnetic element 6 is connected to the pivot axis x at a distance from the pivot axis x in the measuring and control unit 9. The embodiment according to Fig. 4 has the advantage that the use of a bridge extending through the inner cross-section of the channel 1 is unnecessary, so that a further reduction of the pressure loss caused by the closure element within the channel 1 can be achieved.

[0036] Furthermore, the flaps 3, 3' can have a flow-optimized contour, which is also designed to reduce the pressure loss caused by the closure element. When using permanent magnets as the first and second magnetic elements 5, 6, it is also possible to adjust the flap opening pressure to a desired value by varying the distance between the magnets. It is not essential that the magnet pairs 5, 6 are arranged parallel to each other when the flaps 3, 3' are closed. Rather, it is sufficient that they are adequately coupled, which can also be achieved, for example, by an overlapping arrangement of the magnetic elements 5, 6. Moreover, it is advantageous to arrange the two pairs of magnetic elements 5, 6 in such a way that they do not essentially influence each other magnetically.This can be achieved, for example, by arranging the two first magnetic elements 5 associated with the bridge 4 at opposite ends of the bridge 4 and, accordingly, the associated second magnetic elements 6 at opposite ends of the flaps 3, 3'.

[0037] If the flaps 3, 3' are designed as hollow flaps, for example to provide improved thermal insulation, the second magnetic elements 6 can be accommodated in a cavity within the flaps. As described in the subsequently published DE 10 2014 113 210 A1, several of the closure elements 2 according to the invention can also be arranged one behind the other in the channel to form a thermally insulating cavity between them in the closed position. Reference symbol list 1 channel 2 locking element 3, 3' pair of flaps 4 Bridge 5 First magnetic element 6 Second magnetic element 7 stops 8 Contour 9 Measuring and control unit 10 Pressure line 11 cable duct 12 Pressure sensor / pressure line opening 13 Power line x Swivel axis

Claims

[1] Arrangement for volume flow regulation in a fluid channel, wherein the arrangement comprises a channel (1) and at least one closure element (2) arranged in the channel (1), wherein the closure element (2) has at least one pair of flaps (3, 3') which are pivotally mounted on or in the fluid flow direction through the channel (1) behind a web (4) extending through the channel cross-section between an open position in which it at least partially exposes the channel cross-section and a closed position in which it closes the channel (1), wherein the web (4) or the channel (1) has at least one first magnetic element (5), wherein the flaps of the pair of flaps (3, 3') each have at least one second magnetic element (6) which is magnetically coupled to the first magnetic element (5), characterized bythat the distance of the at least one first magnetic element (5) from the pivot axis (x) is less than one fifth of a dimension of the flaps (3, 3') perpendicular to the pivot axis (x), wherein the distance is preferably less than one tenth of the dimension of the flaps (3, 3'). [2] Arrangement according to claim 1, wherein the first and second magnetic elements (5, 6) are arranged relative to one another such that they at least partially overlap in the closed position. [3] Arrangement according to one of the preceding claims, in which the first and the second magnetic element (5, 6) occupy a minimum distance in the closed position, wherein the second magnetic element (6) is guided on a circular path around the pivot axis (x) when the closure element (2) is pivoted from the closed position into the open position, so that the second magnetic element (6) has a maximum distance from the first magnetic element (5) in the open position. [4] Arrangement according to one of the preceding claims, in which, in the case that the channel (1) has the at least one first magnetic element (5), this is arranged on the inner or outer circumference of the channel (1). [5] Arrangement according to one of the preceding claims, in which the web (4) has at least one first magnetic element (5) on opposite sides spaced from the pivot axis (x), wherein both flaps of the pair of flaps (3, 3') each have at least one of the second magnetic elements (6). [6] Arrangement according to claim 5, wherein the first magnetic elements (5) arranged on opposite sides of the web (4) spaced from the pivot axis (x) are further spaced from one another in the longitudinal direction of the web, preferably vertically spaced from one another. [7] Arrangement according to one of the preceding claims, in which the two flaps of the pair of flaps (3, 3') are pivotable about a common pivot axis (x). [8] Arrangement according to one of the preceding claims, in which the web (4) or the channel (1) has a stop (7) against which at least one of the flaps of the pair of flaps (3, 3') rests in the open position, so that the first and the second magnetic element (5, 6) are arranged at a predetermined distance from one another in the open position. [9] Arrangement according to one of the preceding claims, in which the first and / or the second magnetic element (5, 6) comprises a permanent magnet or an electromagnet with adjustable magnetic field strength. [10] Arrangement according to one of the preceding claims, in which the first and the second magnetic element (5, 6) each have a magnetic element with a magnetic field orientation, wherein the two magnetic field orientations are aligned substantially parallel to one another in the closed position, so that the magnetic field orientations in the open position enclose an angle corresponding to an adjustment angle from the closed position to the open position. [11] Arrangement according to one of the preceding claims, in which the web (4) has a fluid-dynamically optimized contour (8) on a first longitudinal side, which is subject to flow when fluid flow is present, wherein the pivot axis (x) about which the flaps (3, 3') are pivotable is arranged on a second longitudinal side opposite the first longitudinal side and lying in the flow shadow of the web (4). [12] Arrangement according to one of the preceding claims, in which at least the first magnetic element (5) has an electromagnet with adjustable magnetic field strength, the arrangement further comprising a measuring and control unit (9) which determines the volume flow through the channel (1) as a function of a magnetic force between the first and the second electromagnet (6) and a pressure loss caused by the closure element (2). [13] Arrangement according to claim 12, in which the measuring and control unit (9) is designed to adjust the magnetic force and thus the setting angle of the flaps (3, 3') by varying the magnetic field strength in such a way that a predetermined volume flow is achieved for a given pressure loss. [14] Arrangement according to claim 12 or 13, wherein the measuring and control unit (9) is designed to determine the pressure loss by forming the difference between a first fluid pressure in the flow direction upstream of the at least one closure element (2) and a second fluid pressure in the flow direction downstream of the at least one closure element (2).

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