Closure device with an asymmetric blade or foil

Abstract

The invention relates to a closure device (1) intended to close an opening (21) of a fluid-supply nozzle (2), the device consisting of a rotor (3) comprising at least one blade (4) carried by a shaft whose axis of rotation (5) is parallel to the axis (22) of the nozzle, the blade alternately closing and opening the opening of the nozzle as it rotates. The blade comprises a closing edge (6) for closing the opening (21), formed by the edge of the blade which, when the nozzle is closing, first comes into alignment with the nozzle, and an opening edge (7) corresponding to the edge of the blade opposite the edge of the blade forming the closing edge, the blade (4) having an asymmetric design.

Description

Description Title of the invention: Foil or asymmetrical blade shutter device

[0001] The present invention may in particular relate to the field of separation of constituents of a medium, preferably a fluid medium, in particular an incompressible fluid, or even a solid or gaseous medium.

[0002] The present invention relates more particularly to a device intended to be implemented in the field of processing cellulosic or non-cellulosic fiber, and more particularly in the field of recycling recovered paper, and especially in the purification of pulp using a sieve or a grid equipped with holes or slots, allowing the separation of the cellulose fibers to be recovered, having a certain three-dimensional bulk, from contaminants having a greater bulk.

[0003] More generally, the invention can be implemented in any technical field in which a fluid is treated by a device, in particular a purification device, resulting in a pressure loss between the upstream and downstream parts of said device.

[0004] Thus, as is known, separation devices, particularly in the field of paper, cardboard, etc. recycling, include a closed and pressurized enclosure or tank, equipped with a perforated cylindrical grid, called a sieve, for separating, according to their size, the different elements that constitute a fluid medium.

[0005] The said tank is equipped, upstream of the screen, with an inlet conduit for the fluid mixture to be purified (the inlet) and, downstream of said screen, with an outlet conduit which rejects the impurities and contaminants which have not passed through the screen (the "refuse"), and an outlet conduit for the mixture free of impurities (the "accepted").

[0006] In the context of paper recycling, recovered paper is first mixed with water, usually in a pulper, so that the cellulose fibers are suspended. After mixing, and obtaining a pulp... For paper containing these fibers and undesirable elements, the aim is to purify only the cellulosic fibers and eliminate the undesirable constituents. Such undesirable constituents may consist of metallic, plastic, or mineral materials, such as staples, ink or glue particles, etc.

[0007] Thus, in this case, the fluid medium which is treated by the separation device consists of a mixture, in the form of a paste, containing undesirable constituents which we wish to separate from the cellulosic fibers to be recovered in order to allow the manufacture, subsequently, of writing paper, newsprint, sanitary paper, packaging, or similar.

[0008] Cellulosic fibers pass through the perforations of the sieve, while contaminants are retained on the upstream side of said sieve.

[0009] The difficulty of the operation lies in the fact that, in order to achieve optimal purification performance, the perforations in the sieve are very fine, generally around 150 pm, and are subject to the risk of clogging.

[0010] Furthermore, it is tempting to work with fairly concentrated paste in order to reduce the size of the equipment, but then the risk of clogging is even greater.

[0011] The risk of clogging also depends, in addition to the size of the perforations, on the type of sieve, the type of fluid mixture whose components must be separated, the pressure upstream of the sieve and the pressure downstream of it.

[0012] It is easy to understand that sieve clogging is problematic, as it prevents the cellulosic fiber separation operation from continuing under optimal conditions.

[0013] Indeed, a buildup of components from the fluid mixture clogging the sieve prevents its selective separation function. If this buildup persists, it risks completely blocking the passage of the accepted particles through the sieve.

[0014] To avoid or reduce this clogging, one solution could be to increase the size of the sieve perforations. However, this solution is not optimal because it would be at the expense of the quality of the differential separation operation based on size.

[0015] Therefore, the solution traditionally implemented to avoid this clogging is to place, in the separation device, a rotor equipped with rotating foils, or blades, for unclogging.

[0016] The rotor is generally positioned close to the screen, often upstream of it, and rotates at a peripheral speed that can be between 10 and 25 m / s.

[0017] At such a rotational speed, each foil, or blade, will locally generate a pressure pulse due to the change in hydraulic flow along the blade.

[0018] This pulsation creates a local depression between the blade and the sieve, which triggers a local counter-current of paste, from downstream to upstream, passing through the sieve.

[0019] Thus, the mass of constituents that is clogged on the sieve is broken up, evacuated through the reject pipe, and the perforations are unclogged, with each pass of the blade.

[0020] However, the solution of the rotor with blades or foils for cleaning has several disadvantages.

[0021] In particular, the number and design of the foils, or blades, in terms of air gap and profile shape, are fixed. Therefore, the frequency, intensity, and duration of the cleaning process can only be modified by influencing the rotor speed.

[0022] Modifying the rotor speed, particularly its acceleration, certainly allows for changing the frequency and intensity of cleaning, but it has the disadvantage of generating damaging overconsumption of energy, and a decrease in selectivity in separation.

[0023] On an industrial scale, a decrease in separation selectivity generates additional costs, as well as faster wear, particularly at the level of the blades.

[0024] In the international application published under number WO 2017 / 125692 in the name of the same company as the present patent application, a device for separating the constituents of a fluid medium is described, in the form of a closed enclosure equipped with a separating element, in particular a sieve, and connected to at least one conduit.

[0025] In the design of this state-of-the-art device, the pressure pulse to enable the unclogging of the sieve is generated here by a sealing means located at the level of one of the conduits connected to the enclosure, and capable of allowing total or partial sealing of said conduit.

[0026] More specifically, the sealing means include at least one element fixed on a movable support. Said element is intended to seal, or not, completely or partially, the conduit, depending on its position and its geometric shape relative to said conduit.

[0027] Such means of closure may consist of a shovel valve, ball valve, gate valve, deformable obturator, or butterfly valve.

[0028] That being said, the overall size and height of the valves are important, so the space required for their installation is also important.

[0029] In addition, during the opening and closing process, the valve's sealing surface is relatively abrasive and prone to wear, even at high temperatures.

[0030] The gate valve also typically has two sealing surfaces, which makes processing, grinding, and maintenance more difficult.

[0031] The valves also have the disadvantage of having a long opening and closing time, so this solution is not suitable for the applications in question, especially since said valves are subject to extremely rapid wear in such applications.

[0032] According to another preferential example described in more detail in this prior art document, the obturating means consist of a rotating disc. The disc then comprises a support frame and at least one obturating flap for the duct, said disc serving as a support means for the flap.

[0033] One such example of means of sealing this prior art document is shown in Figure 1 of the attached drawings, for information purposes.

[0034] The continuous rotation of the disc causes the continuous rotation of the obturator flap, which then progressively obturates the duct. The flap is mobile, following this continuous movement, during the separation process of the medium's components, during a phase known as "activation," which results in mobility of the flap's support mechanism and therefore of the flap itself.

[0035] Indeed, in this document, it is proposed an activation of the shuttering means, by suitable control means, to activate and deactivate this shuttering means cyclically, according to a given frequency, each cycle comprising an activation phase and an inactivation phase of the shuttering means.

[0036] Thus, during its activation phase, the sealing device is capable of progressively varying the degree of blockage in the conduit, between a minimum and a maximum value, in order to adjust the pressure pulsation, particularly according to the operating conditions of the purification and clogging device, to improve screen unclogging. During its inactivation phase, the sealing device is fixed.

[0037] That being said, although this solution allows the creation of a pressure well to unclog the sieve or limit the formation of a mass on this sieve, some disadvantages still remain.

[0038] In particular, the impulse effect can be improved to optimize sieve unclogging.

[0039] On the one hand, the execution and control of a cycle, comprising an activation phase where the sealing device is continuously moving and an inactivation phase where said sealing device is stationary, is complex and requires precise adjustments via appropriate control and monitoring systems. In particular, an excessively long closure time of the conduit forces fluid flow through the screen, which can accelerate the formation of a fiber mat on the screen, clogging it.

[0040] Furthermore, at a constant rotational speed of the sealing means, the pipe is likely not to be sealed long enough for the pressure to increase sufficiently in the circuit to allow effective unclogging.

[0041] Finally, at too high a rotation speed, in addition to necessarily generating significant energy consumption, the closing speed of the conduit can be too high and produce a "water hammer" effect likely to cause damage to the equipment.

[0042] Other prior art documents describe rotor devices of various designs, including documents DE 198 07 503, US 4 953 595, and DE 10 2012 023078.

[0043] Documents DE 198 07 503 and DE 10 2012 023078 refer to devices for closing an opening in the form of a rotating disc, itself having one or more openings. These devices are not intended for applications in the separation of components of a medium, nor do they aim to generate pulsations in a flow.

[0044] In the device of US patent 4,953,595, which relates to a mud impulse valve comprising a body, a stator, and a rotor rotatably arranged within the body and capable of rotating relative to the stator, the stator has a plurality of stator ports and the rotor has a plurality of rotor ports. Each stator port corresponds to a rotor port, and the stator ports are configured within the stator in a geometric configuration analogous to the configuration in which the rotor ports are arranged and configured within the rotor. Thus, a predetermined rotation of the rotor relative to the stator causes the simultaneous opening and closing of the stator and rotor ports.The stator orifice and the rotor orifice are open when the stator orifice and the rotor orifice are at least partially aligned with each other, and the stator orifice and the rotor orifice are closed when no part of the stator orifice overlaps any part of the rotor orifice.

[0045] However, these devices are not suitable for the applications referred to in this application, and do not make it possible to remedy the disadvantages of the other separation devices, equipped with various means of sealing a conduit for unclogging a sieve, already mentioned above.

[0046] The present invention is intended to remedy, at least in part, the drawbacks of prior art devices.

[0047] In an inventive approach, it was conceived to modify the design of the sealing device so that it would allow, under easy-to-implement conditions of use, a closure of the conduit that is not too abrupt, while guaranteeing a sufficient closure time to allow the fastest possible opening, generating a sudden drop in pressure in the system to improve the unclogging effect of the sieve.

[0048] To this end, the invention relates to a shuttering device intended to close an orifice of a fluid supply nozzle, in particular intended to be integrated into a device for separating the constituents of a fluid medium, said shuttering device consisting of a rotor comprising at least one foil, or a blade, in the form of a plate, said at least one blade being carried by a shaft whose axis of rotation is parallel to the axis of said supply nozzle, said at least one blade coming, according to its rotation, to close and open, alternately, the orifice of said supply nozzle in order to generate unclogging pulsations on the circuit.

[0049] Said at least one blade comprises a closing front and an opening front of said orifice, said closing front being constituted by the edge of said blade coming first, when closing the nozzle, at the right of said nozzle, while said opening front corresponds to the edge of the blade opposite the first edge of the blade constituting the closing front.

[0050] The shutter device of the invention is particular in that said at least one blade comprising it has an asymmetrical design, and whose closing front is a straight line or a curved shape, said straight line, or respectively a straight line passing through the centroid of the curved shape and the inner end of the rotor of said blade closing front, forming an angle α with a straight line radial passing through said inner end, while the opening front is a straight line or a curved shape, said straight line, or respectively a straight line passing through the centroid of the curved shape and the inner end of the rotor of said opening front of the blade, forming an angle [3 with a radial line passing through said inner end, with a greater than [3, so that the opening speed of said orifice of the feed nozzle is greater than the closing speed of the same orifice.

[0051] Advantageously, said at least one blade in the form of a plate corresponds to an annular portion positioned externally or internally with respect to an inner circle whose center corresponds to the axis of rotation of the rotor shaft.

[0052] Preferably, said closing front of said at least one blade consists of a straight line tangent to the inner circle of the rotor such that the angle a is equal to 90°.

[0053] In a different embodiment, said closing front of said at least one blade has a convex shape.

[0054] The said closing front can then advantageously consist of an arc of a circle whose center of radius of curvature is on the side of the blade.

[0055] The said closing front of said at least one blade may also form a curve tangent to the inner circle of the rotor and whose center of radius of curvature is on the side of the blade.

[0056] As regards the said opening front, it may in particular consist of a radial line whose axis passes through the axis of rotation of the rotor, so that the angle [3 is equal to 0.

[0057] The said opening front may also have, in another embodiment, a concave shape.

[0058] Preferably, said opening front has a cut in a portion of a circle or in an arc of a circle and, when it has a cut in a portion of a circle, this is advantageously to the dimensions of the orifice of the fluid supply nozzle, so as to coincide closely with said orifice when the opening front passes over said orifice.

[0059] The said shutter device may advantageously comprise between one and five blade(s).

[0060] The invention also relates to a device for separating the constituents of a fluid medium, with constituents of interest to be recovered and contaminants to be eliminated, said separation device comprising, in an enclosure, a separation element for said constituents, such as a sieve, suitable for allowing the passage, downstream of said sieve, of the constituents of interest, while retaining, upstream of said sieve, said contaminants, said enclosure being connected, upstream of said separation device, taking into account the direction of flow of the fluid medium, to a supply line for the enclosure with fluid medium and to a discharge line for the rejects, said enclosure being further connected, downstream of the separation device, to a discharge line for the accepteds, said separation device then incorporating at least one shut-off device according to the present invention, positioned on at least one of the lines connected to said enclosure.

[0061] Other objects and advantages of the present invention will become apparent during the following description relating to embodiments which are given only as indicative and non-limiting examples.

[0062] Understanding this description will be facilitated by referring to the attached drawings, in which:

[0063] [Fig.1] represents a schematic top view of a duct closure device known in the prior art.

[0064] [Fig.2] represents a schematic front view of three rotor geometries that can be used in the shuttering device of Figure 1, or in any other shuttering device, the illustration on the left of Figure 2 representing a five-bladed rotor or foils, the middle one a two-bladed rotor, while the one on the right shows a three-bladed rotor.

[0065] [Fig.3] illustrates, schematically and from the front, a first embodiment of a shutter device according to the invention.

[0066] [Fig.4] illustrates, schematically and from the front, a second embodiment of a shutter device according to the invention.

[0067] [Fig.5] illustrates, schematically and from the front, a third embodiment of a shutter device according to the invention.

[0068] [Fig.6] illustrates, schematically and from the front, a fourth embodiment of a shutter device according to the invention.

[0069] [Fig.7] illustrates, schematically and from the front, three more embodiments of a sealing device according to the invention.

[0070] [Fig.8] schematically represents a shuttering device, according to the present invention, and corresponding to that illustrated in figure 6, intended to be integrated into an installation for separating the constituents of a fluid medium.

[0071] [Fig.9] corresponds to a graph illustrating the pressure (in bar) inside a purification device, as a function of time, expressed in seconds (s), measured at different rotation speeds (in rpm, or revolutions per minute - tr / min) of the new shutter device of the invention, namely at 6.7 rpm or tr / min, at 5.4 rpm or tr / min and at 4 rpm or tr / min.

[0072] [Fig.10] corresponds to a graph illustrating the pressure (in bar) inside a purification device as a function of time (in s), measured in the accepted pipe, on the one hand with the new shutter device of the invention (grey curve on the figure) and on the other hand with an old two-blade shutter device whose geometry is similar to that illustrated in Figure 2, at the centre of the latter (black curve on the figure), at an equivalent rotation speed for the two rotors, on the order of 7 rpm or rpm.

[0073] [Fig.11] corresponds to a graph illustrating the pressure (in bar) inside a purification device as a function of time (in s), measured in the accepted pipe, on the one hand with the new obturator device of the invention (dark grey curve on the figure) and on the other hand with an old two-blade obturator device whose geometry is similar to that illustrated in Figure 2, at the center of the latter (light grey curve on the figure), at a different rotation speed for the two rotors, namely 6.7 rpm or rpm for the new rotor, and 2 rpm or rpm for the known two-blade device.

[0074] With reference to figures 3 and following of the attached drawings, the present invention relates, then, to a shutter device 1 intended to close an orifice 21 of a fluid supply nozzle 2.

[0075] Such a shutter device 1 according to the invention can be, in particular, but not limited to, integrated into a device for separating the constituents of a fluid medium.

[0076] Note that the medium whose components must be separated could just as easily consist of a solid medium or a gaseous medium.

[0077] The present shutter device 1 can advantageously be used in the field of filtration, purification, fractionation, thickening, in particular of cellulosic fibers or textile fibers, or any other type of fiber.

[0078] The said shutter device 1 of the present invention can thus, in a particularly advantageous manner, be integrated into separation devices, particularly in the paper industry, especially for the recycling of recovered paper and / or cardboard.

[0079] The paper, in other words the cellulosic fibers that compose it, will indeed have to be purified to eliminate undesirable constituents, such as those already mentioned previously (glues, staples, ink, various plastic, metallic or mineral materials) in order to be reused later for the manufacture of recycled paper.

[0080] It should be noted that the shutter device 1 according to the present invention can also be used in the field of the textile industry, and in particular, again, in the recycling of textile fibers, and therefore in the separation of these from potential contaminants which can be of various kinds (metallic or plastic in particular), and in the recovery of these fibers for reuse in the manufacture of recycled textiles.

[0081] The shutter device 1 of the present invention can also be used in the design of separation devices intended for use in wastewater treatment plants, in order to separate the polluting or non-polluting waste, in particular waste with a large size or bulk.

[0082] Indeed, the water to be treated may contain mineral matter, such as pebbles, soil particles, or any other undesirable element, for example plastics, which must be removed in order to continue the treatment.

[0083] A separation device in which the shutter device 1 of the invention can be integrated, as well as its design and the various elements which constitute it, will be described in more detail below.

[0084] Returning now to the design of said shutter device 1 of the invention, this consists more specifically of a rotor 3 comprising, on the one hand, at least one foil 4, or a blade 4, in the form of a plate, and, on the other hand, a shaft, the axis of rotation 5 of which is parallel to the axis 22 of said feed nozzle 2.

[0085] Thus, said at least one blade 4 corresponds to an annular portion 41 positioned preferably externally, but which can also be positioned internally, in relation to an internal circle 31 whose center corresponds to the axis of rotation 5 of the rotor shaft 3.

[0086] The rotation of the shaft by means of driving causes that of said at least one blade 4, in a direction of rotation illustrated on the figures by an arrow, in this case in a counterclockwise direction, and said blade 4 comes, according to its rotation, to close and open, alternately, the orifice 21 of said fluid supply nozzle 2.

[0087] The cyclical closing and reopening of this orifice 21 has the effect of creating, in the circuit of the installation at the level of which the obturator device 1 is positioned, pulsations of unclogging of a separation means, of the sieve type, also integrated in said installation.

[0088] The present shutter device 1 is therefore constituted, on the one hand, by a closing front 6 and, on the other hand, by an opening front 7 of the orifice 21 of the fluid supply nozzle 2.

[0089] The closing front 6 is formed by the edge of the blade 4 which comes first, when closing the orifice 21 of the nozzle 2, directly opposite it.

[0090] As regards the opening front 7, it corresponds to the edge of the blade 4 which is opposite the first edge of the blade 4 constituting the closing front 6.

[0091] Note that, although figures 3 to 7 of the attached drawings illustrate a particular and highly preferred embodiment of the shutter device 1 of the invention, comprising a single blade 4, said shutter 1 may, in other embodiments, comprise a plurality of blades 4.

[0092] Thus, depending on the size of the shutter device 1, the length of the blades 4, and also depending on the intended application, said device 1 may in particular comprise one or more blade(s) 4, advantageously identical but which may be different, distributed, preferably, regularly on the periphery of the inner circle 31 of the rotor 3.

[0093] In the description that follows, reference may be made to a shutter device 1 comprising a single blade 4; however, the characteristics that will be described shall apply to the shutter device 1 whether it comprises one or more blade(s) 4.

[0094] According to a particular feature of the shutter device 1 of the invention, said at least one blade 4 which it comprises has an asymmetrical design.

[0095] In this asymmetrical design, in particular, the closing front 6 of the orifice 21 of the fluid supply nozzle 2 can be constituted by a straight line, as illustrated in particular in figures 3, 5, 6 as well as in the different configurations found in figure 7.

[0096] That being said, said closure front 6 can also consist of a curved shape, as seen in the attached figure 4.

[0097] In the first case, when said closing front 6 of the blade 4 is made up of a straight line, the latter forms an angle a with a radial line d1 passing through the end 61 of said closing front 6 which is internal to the rotor 3 of the shutter device 1.

[0098] In the second case mentioned above, namely a curved closing front 6 of the blade 4, it is the straight line det passing, on the one hand, through the centroid Bf of said curved shape constituting said closing front 6 and, on the other hand, through the inner end 61 of the rotor 3 of said closing front 6, which forms an angle a with the radial line d1 passing through the end 61 of said closing front 6 which is internal to the rotor 3 of the shutter device 1.

[0099] As regards the opening front 7 of the orifice 21 of the fluid supply nozzle 2, this can be, just like the closing front 6, a straight line or a curved shape.

[0100] An opening front 7 in the form of a straight line is visible in figures 3, 4, 5 as well as in the different configurations of the shutter device 1 shown in figure 7, while a curved opening front 7, in this case in the form of a semicircle, is illustrated in figures 6 and 8.

[0101] In the first case, when said opening front 7 of the blade4 is made up of a straight line, the latter forms an angle p with a radial line d2 passing through the end 71 of said opening front 7 which is internal to the rotor 3 of the shutter device 1.

[0102] When the opening front 7 of the blade 4 consists of a curved shape, it is the straight line deo passing, on the one hand, through the barycenter B oof the curved shape constituting said opening front 7 and, on the other hand, by the internal end 71 to the rotor 3 of said opening front, which forms an angle p with the radial line d2 passing through the end 71 of said opening front 7 which is internal to the rotor 3 of the shutter device 1.

[0103] All the configurations of the closing fronts 6 and opening fronts 7 of the blade 4 which have been described previously can be combined, namely that said blade 4 can present its two opening and closing fronts in the form of a straight line, or its two fronts in the form of a curve, or one of the two fronts is a straight line while the other is a curve.

[0104] That being said, whatever the configuration chosen, it is necessary to respect the characteristic according to which the angle a, at the level of the closing front 6, is greater than the angle [3 of the opening front 7, so that the opening speed of the orifice 21 of the fluid supply nozzle 2 is greater than the closing speed of said orifice 21.

[0105] Indeed, respecting this relationship with a>p, the blade 4 will have to undergo a greater angular rotation to close the orifice 21 of the nozzle 2, than to perform the operation of opening this same orifice 21, so that the opening of said orifice 21 can be carried out more quickly than its closing.

[0106] With reference now to Figure 2 of the attached drawings, and also to Figure 1, illustrating different rotor designs known from the prior art and which can be implemented in applications similar to those covered by this application, it should be noted that the blades of each of these sealing devices have a symmetrical design.

[0107] In addition, the closing and opening fronts are generally radial with the axis of rotation of the rotor, as illustrated in particular in the attached figure 2, especially in the illustration on the left.

[0108] Thus, at a constant rotational speed of a rotor equipped with such blades, the speed at which an orifice is closed by such a blade, when it passes over said orifice, is equal to the speed at which this orifice is then reopened.

[0109] On the contrary, by means of the present shutter device 1 and its asymmetrical design with regard to the blade 4, it is possible to obtain, by means of a constant rotation speed of the rotor 3, on the one hand a closing speed of the orifice 21 of the nozzle 2 by said blade 4 which is less than the reopening speed of this same orifice 21 while allowing, on the other hand, a sufficiently long closing time of the orifice 21.

[0110] However, obtaining a sufficient closure time is essential to allow sufficient overpressure to be achieved inside a circuit or device or installation equipped with such a shutter device 1, while reopening the fluid supply nozzle 2 as quickly as possible will generate a sudden drop in pressure in the circuit in which it is installed.

[0111] Therefore, the instantaneous flow rate of fluid through the feed nozzle 2 will be momentarily greater when its orifice 21 is rapidly reopened, resulting in a high flow velocity upstream of said nozzle 2, for example along a separation means, such as a sieve or other, positioned for example upstream of the shutter device 1 considering the path of the fluid, and therefore a depression.

[0112] The depression thus generated will allow for effective unclogging of the sieve, in the aforementioned case.

[0113] According to a particular and preferred embodiment of the closing front 6 of said blade 4, which is represented in particular in figures 3, 5 and 6 of the attached drawings, said closing front 6 consists of a straight line tangent to the inner circle 31 of the rotor 3 such that the angle a that said front 6 forms with the radial line d1 is equal to 90°.

[0114] However, in other configurations, notably those shown in Figure 7, the closing front 6 also consists of a straight line, without this line being tangent to the inner circle 31 of the rotor. Thus, it can be understood that the angle a can also have a value less than 90°.

[0115] With reference now to Figure 4, representing another embodiment of the shutter device 1 in which the closing front 6 of the blade 4 consists of a curve, this is preferably convex in shape, and advantageously consists of an arc of a circle whose center of radius of curvature is on the side of the blade 4, or forms a curve tangent to the inner circle 31 of the rotor 3 and whose center of radius of curvature is on the side of the blade 4.

[0116] Thus, in this aforementioned configuration, the angle a between the radial line d1 and the line det passing, on the one hand, through the barycenter Bf of the curved shape constituting the closing front 6 and, on the other hand, through the internal end 61 of the rotor 6 of the closing front 6, has a value greater than 90°.

[0117] With regard to the said opening front 7, this can consist of a radial line whose axis passes through the axis of rotation 5 of the rotor, so that the angle p is equal to 0. This possibility is illustrated in particular in figures 3 and 4, and in the representation on the left of figure 7.

[0118] That being said, and as shown in Figure 5 or in the middle and right illustrations of Figure 7, the opening front 7 of the blade 4 can also consist of a straight line making an angle p > 0 with a radial line d2 passing through the axis of rotation 5 of the rotor 3.

[0119] The said opening front 7 of the blade 4 of the shutter device 1 of the invention can also be in a concave form, a variant of this embodiment of the blade 4, particularly preferred, being visible in figure 6.

[0120] Thus, more specifically, in this figure, the opening front 7 presents, according to a particularly privileged design, a cut in a portion of a circle, in this case a portion in a semicircle, considering however that it is also conceivable that the opening front 7 of the blade 4 consists of an arc of a circle.

[0121] Advantageously, when the opening front 7 consists of a portion of a circle, this portion is the same size as the orifice 21 of the fluid supply nozzle 2, so as to coincide closely with said orifice 21 when the opening front 7 passes over said orifice 21, thus allowing the fastest possible opening of the latter.

[0122] In this case, it was possible to obtain an opening speed such that said orifice 21 is opened in a time less than 0.1 s.

[0123] The shutter device 1 having the characteristics of the present invention is particularly interesting.

[0124] It provides a robust and particularly easy-to-use system, since the rotor 3 is rotated at a constant speed while allowing the nozzle 2 to open faster than it closes faster, by means of the asymmetry of the opening 7 and closing 6 fronts, while the duration for which the nozzle is closed is managed by the geometry of the rotor 3, in particular that of the blade 4, and by the speed at which the rotor 3 is rotated.

[0125] Thus, the said shutter device 1 of the invention can allow, in an installation which will be described in more detail below, periodic and continuous operation, using a motor whose rotational speed is constant.

[0126] The opening signal of the orifice 21 of the feed nozzle 2 is customizable, depending on the geometry of the blade 4 of the rotor 3, and the rotational speed of its drive motor.

[0127] While maintaining a constant rotation speed, the device of the invention makes it possible to generate an asymmetric signal resulting in an opening time of the orifice 21 of the nozzle 2 that is different from its closing time and, as already indicated above, a different, in this case greater, opening speed of said orifice 21, compared to the speed at which it is closed.

[0128] The said shuttering device 1 of the invention also makes it possible to increase the number of periods per minute without changing the rotational speed of the rotor, by adding one or more blade(s) 4 to the periphery of the rotor 3. Thus, by means of two blades 4, for example, it is possible to obtain two periods per rotation of the rotor 3.

[0129] Note that the duration of a period (or cycle) using device 1 of the invention can be between 60 s and 2 s.

[0130] Furthermore, it was estimated that said shutter device 1 could operate for more than 21,000,000 cycles without degradation of its performance.

[0131] Let us also recall here that the said shutter device 1 is capable of handling heterogeneous flows, i.e. fluid, solid, or gaseous.

[0132] Thus, according to a particular application of the shutter device 1 of the invention, it is part of a more global device or installation for separating the constituents of a fluid medium, with constituents of interest to be recovered and contaminants to be eliminated, said constituents of interest consisting, in particular, of cellulosic or textile fibers mixed, within a paste or fibrous suspension, with water and contaminants.

[0133] Such a separation device includes, within an enclosure, a separation element for said constituents, such as a sieve, capable of allowing the passage, downstream of said sieve, of the constituents of interest, in this case the cellulosic or textile fibers, while retaining, upstream of said sieve, said contaminants.

[0134] Such an enclosure is traditionally connected, upstream of said separation device, taking into account the direction of flow of the fluid medium (the fibrous suspension), to a fluid supply line for the enclosure.

[0135] Furthermore, the enclosure is connected to a reject evacuation line, corresponding to the constituents of the fibrous suspension (contaminants and fibers) which have not passed through the sieve, while, downstream of the separation device, an accepted outlet line is connected to the enclosure for the evacuation of the purified fibers.

[0136] According to the present invention, said separation device, or said installation, is particular, or particular, in that it incorporates at least one shutter device 1 as described above, positioned on at least one of the pipes connected to said enclosure.

[0137] It is therefore conceivable that both the accepted and rejected lines are equipped with a shuttering device 1 according to the invention, or that a single device 1 is integrated into the installation, preferably on the rejected line, without this being limiting, a single shuttering device 1 can also be positioned on the accepted line.

[0138] Figure 8 schematically illustrates part of a shutter device 1, in one of its preferred designs, intended to be connected to a pipe of an installation for separating the constituents of a medium, the arrival of the fluid medium being symbolized by an arrow on the said figure.

[0139] In order to illustrate the effect and interest of the shutter device 1 of the invention when incorporated into an installation for separating constituents of a fluid medium, comparative tests were carried out in particular with a rotor previously known from the prior art, and a shutter device 1 according to the preferred design illustrated in the attached figures 6 and 8.

[0140] These tests will now be described with reference to the attached figures 9, 10 and 11.

[0141] As a preliminary remark, it should be noted that previous tests, the results of which are not repeated here, have shown that an increase in rotor speed, considering a geometry previously known in the prior art, namely a two-bladed or bifoil rotor as shown in Figure 2, leads to a decrease in the peak pressure measured in the accepted pipe of a component separation installation of a mixture.

[0142] Such a decrease in peak pressure is due to the geometry of the rotor, which does not allow a sufficiently long closure of the pipe for the pressure to increase sufficiently.

[0143] The sealing device 1 according to the invention makes it possible to solve this problem.

[0144] Indeed, it is visible, in the attached figure 9, which represents pressure curves (in bar) measured as a function of time, in a component separation installation, with different speeds (4, 5.4 and 6.7 rpm or tr / min) of rotation of the rotor 3 of the sealing device 1 of the invention, that an increase in the speed of said rotor 3 does not decrease the value of the pressure peak, or does so negligibly.

[0145] It can be deduced that the new rotor design allows for a reduction in the rotational speed of the screening rotor, also known as the screen rotor, which can be positioned, for example, inside the sieve consisting of a cylindrical grid. Indeed, for the prior art two-bladed rotor, the rotational speed of the screen rotor has been reduced by 30%, which is the limiting speed below which the sieve clogging occurs.

[0146] With the sealing device 1 of the invention which has been tested, the rotation speed of the screen rotor could be reduced from 40% to 55% under very stable conditions (no clogging), and clogging only appeared at a lower rotation speed of the screen rotor.

[0147] Such a reduction in the rotational speed of the screen rotor, made possible when implementing a shutter device 1 of the invention, inevitably leads to a reduction in the energy consumption of the installation, and, consequently, allows for a reduction in costs in the long term.

[0148] Furthermore, it appears from the graph in Figure 11 that, by means of the present shutter device 1, the closing time of the orifice 21 of the nozzle Supply pressure 2 is sufficient to achieve equilibrium pressure for the three speeds that have been tested here.

[0149] Indeed, for all three rotor 3 rotation speeds tested, and even at the highest speed of 6.7 rpm, the pressure peak plateaus, indicating that equilibrium pressure has been reached. This pressure then drops sharply during the rapid opening made possible by the specific design of the blade's opening face.

[0150] It can be deduced that the rotational speed of the rotor 3 of the shutter device 1 of the invention can be further increased and / or that the open surface of the rotor can be increased.

[0151] With reference now to Figure 10, this allows us to compare the pressure peaks obtained in the accepted pipe of an installation, representing the pressure peaks (in bar) obtained inside the screen, with a shutter device 1 of the invention positioned in said installation, or with a bifoil or bi-blade rotor of the prior art, as a function of time (in s).

[0152] For these tests, the speed of the screening screen rotor was 12 m / s with the two-bladed rotor in the installation, and 10 m / s with the shutter device 1 of the invention in the installation.

[0153] The graph in Figure 10 illustrates that the presence of the two-bladed rotor in the installation produces a pressure peak, without however reaching a plateau.

[0154] At equivalent rotational speed, the pressure peak allowed by the shutter device 1 of the invention is significantly greater than that generated by the rotor of the prior art, so that, during rapid reopening, the pressure drop is particularly significant and rapid for effective unclogging of the screen.

[0155] The graph in Figure 11, meanwhile, allows us to compare the pressure peaks generated by the shutter device 1 of the invention when the rotor 3 is rotated at a higher speed (6.7 rpm or tr / min) than a two-bladed rotor of the prior art, whose rotation speed is maintained only at 2 rpm or tr / min.

[0156] Here again, the pressure peak produced by means of the prior art rotor does not allow a plateau to be reached, and therefore the equilibrium pressure, compared with the shutter device 1 of the invention, although the latter operates at a significantly higher rotational speed.

Claims

Demands

1. A shutter device (1) for closing an orifice (21) of a fluid supply nozzle (2), particularly for integration into a device for separating the components of a fluid medium, said shutter device (1) comprising a rotor (3) having at least one blade (4) in the form of a plate, said at least one blade (4) being carried by a shaft whose axis of rotation (5) is parallel to the axis (22) of said supply nozzle (2), said at least one blade (4) alternatingly opening and closing the orifice (21) of said supply nozzle (2) as it rotates, in order to generate cleaning pulsations in the circuit, said at least one blade (4) comprising a closing face (6) and an opening face (7) of said orifice (21), said closing face (6) being formed by the edge of said blade (4) coming first, when the nozzle (2) is closed, at the right of said nozzle (2),whereas said opening front (7) corresponds to the edge of the blade (4) opposite the first edge of the blade constituting the closing front (6), said shutter device (1) being characterized in that said at least one blade (4) has an asymmetrical design, and whose closing front (6) is a straight line or a curved shape, said straight line, or respectively a straight line (det) passing through the centroid (Bf) of the curved shape and the inner end (61) to the rotor (3) of said closing front (6) of the blade (4), forming an angle α with a radial line (d1) passing through said inner end (61), whereas the opening front (7) is a straight line or a curved shape, said straight line, or respectively a straight line (dBo) passing through the centroid (B, o) of the curved shape and the inner end of the rotor (71) of said opening front (7) of the blade (4), forming an angle p with a radial line (d2) passing through said inner end (71), with a greater than p, so that the opening speed of said orifice (21) of the feed nozzle (2) is greater than the closing speed of the same orifice (21).

2. A shutter device (1) according to claim 1 characterized in that said at least one blade (4) in the form of a plate (41) corresponds to an annular portion positioned externally or internally with respect to an inner circle (31) whose center corresponds to the axis of rotation (5) of the rotor shaft (3).

3. Shutter device (1) according to claim 2 characterized in that said closing front (6) of said blade (4) consists of a straight line tangent to the inner circle (31) of the rotor (3) such that the angle a is equal to 90°.

4. Shutter device (1) according to claim 2 characterized in that said closing front (6) of said at least one blade (4) has a convex shape.

5. Shutter device (1) according to the preceding claim characterized in that said closing front (6) consists of an arc of a circle whose center of radius of curvature is on the side of the blade (4).

6. A shutter device (1) according to claim 4 characterized in that said closure front (6) of said at least one blade (4) forms a curve tangent to the inner circle (31) of the rotor (3) and whose center of radius of curvature is on the side of the blade (4).

7. Shutter device (1) according to any one of the preceding claims characterized in that said opening front (7) is a radial line whose axis passes through the axis of rotation (5) of the rotor (3), such that the angle p is equal to 0.

8. Shutter device (1) according to any one of claims 1 to 6 characterized in that said opening front (7) has a concave shape.

9. Shutter device (1) according to the preceding claim characterized in that said opening front (7) has a cut in a portion of a circle or in an arc of a circle.

10. A shutter device (1) according to the preceding claim characterized in that said portion of the circle of the opening front (7) is the same size as the orifice (21) of the fluid supply nozzle (2), so as to coincide closely with said orifice (21) when the opening front (7) passes over said orifice (21).

11. Shutter device (1) according to any one of the preceding claims characterized in that it comprises between one and five blades (4).

12. A device for separating the constituents of a fluid medium, with constituents of interest to be recovered and contaminants to be eliminated, said separation device comprising, in a chamber, a separating element for said constituents, such as a sieve, suitable for allowing the passage, downstream of said sieve, of the constituents of interest, while retaining, upstream of said sieve, said contaminants, said chamber being connected, upstream of said separation device, taking into account the direction of flow of the fluid medium, to a fluid medium supply line to the chamber and to a reject line, said chamber being further connected, downstream of the separation device, to an accepted outlet line, said separation device being characterized in that it incorporates at least one shut-off device (1) according to one of the preceding claims, positioned on at least one of the lines connected to said chamber.

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