Asymmetric foil shutter device
The asymmetrical shutter device addresses sieve clogging in paper recycling by controlling nozzle closure and reopening to unclog sieves efficiently, reducing energy consumption and wear, thus enhancing separation performance.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- KADANT LAMORT
- Filing Date
- 2024-06-17
- Publication Date
- 2026-05-22
AI Technical Summary
Existing separation devices for recycling paper face issues with sieve clogging due to fine perforations, leading to operational inefficiencies and increased energy consumption, especially when using concentrated pastes, and traditional unclogging methods like rotors with blades or valves are inefficient and wear-prone.
A shutter device with asymmetrical blades is introduced, allowing for controlled closure and rapid reopening of fluid supply nozzles, generating pressure pulsations to unclog sieves effectively while reducing energy consumption and wear.
The asymmetrical shutter device ensures efficient unclogging of sieves with reduced energy use and extended operational lifespan, maintaining separation quality and reducing equipment wear.
Smart Images
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Abstract
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 in particular 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, in a known manner, separation devices, particularly in the field of recycling paper, cardboard, etc., comprise 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] 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 with 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, generally in a pulper, so that the cellulose fibers are suspended. After mixing, and obtaining a paper pulp containing these fibers and undesirable elements, the aim is to purify the cellulose fibers only 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, presenting 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] The cellulosic fibers pass through the perforations of the sieve, while the 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 on the order of 150 pm, and are subject to the risk of clogging.
[0010] Moreover, 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 clogging of the sieve is problematic, because it prevents the cellulosic fiber separation operation from continuing under optimal conditions.
[0013] Indeed, a clump of constituents from the fluid mixture clogging the sieve prevents its selective separation function. If this clump 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 compromise the quality of the size-dependent differential separation operation.
[0015] Also, 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] Said rotor is generally positioned near the screen, often upstream of it, and rotates at a peripheral speed which 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 which 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 value and profile shape, are fixed. Therefore, the frequency, the intensity and the duration of the cleaning can only be modified by influencing the rotational speed of the rotor.
[0022] Modifying the rotor speed, in particular its acceleration, certainly allows changing the frequency and intensity of cleaning, but it has the disadvantage of generating a damaging overconsumption of energy, and a decrease in selectivity in the 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 prior 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 comprise 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 sealing surface of the valve is relatively abrasive, and subject to wear, even at high temperatures.
[0030] The gate valve also generally 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 that this solution is not suitable for the applications which are targeted, especially since said valves are subject to extremely rapid wear in such applications.
[0032] According to another preferred example described in more detail in this prior art document, the sealing means consist of a rotating disc. The disc then comprises a support frame and at least one sealing flap for the duct, said disc serving as a support means for the flap.
[0033] Such an example of means of sealing this prior art document is shown in [Fig.1] of the accompanying drawings, for information purposes.
[0034] The continuous rotation of the disc causes the continuous rotation of said sealing flap, which will progressively seal the duct. The flap is then mobile, according to this continuous movement, during the process of separating the constituents of the medium, during a so-called "activation" phase which results in a mobility of the flap support means 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 means 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 the unclogging of the screen. In its inactivation phase, the sealing means 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 the unclogging of the sieve.
[0039] On the one hand, the execution and control of a cycle, comprising an activation phase where the sealing means is continuously moving and an inactivation phase where said sealing means is stationary, is complex and requires precise adjustments through suitable control and monitoring means. In particular, an excessively long closure time of the conduit forces fluid flow through the sieve, which is likely to accelerate the formation of a fiber mat on the sieve, 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 the fact that it necessarily generates a significant consumption of energy, the closing speed of the conduit may be too high and produce a "water hammer" effect likely to cause damage to the equipment.
[0042] The present invention is intended to remedy, at least in part, the drawbacks of prior art devices.
[0043] In an inventive approach, it was conceived to modify the design of the sealing device, so that it allows, under easy-to-implement conditions of use, a closure of the conduit that is not too abrupt, while guaranteeing a closure time sufficient to allow the fastest possible opening, generating a sudden pressure drop in the system to improve the unclogging effect of the sieve.
[0044] 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.
[0045] 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.
[0046] The shutter device of the invention is particular in that said at least one blade which it comprises 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 center of the curved shape and the inner end of the rotor of said closing front of the blade, forming an angle α with a radial line 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 center 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 α 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.
[0047] 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.
[0048] Most 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 α is equal to 90°
[0049] In a different embodiment, said closing front of said at least one blade has a convex shape.
[0050] 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.
[0051] Said closing front of said at least one blade can 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.
[0052] As regards now said opening front, this 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.
[0053] Said opening front may also have, in another embodiment, a concave shape.
[0054] Most 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.
[0055] Said shutter device may advantageously comprise between one and five blade(s).
[0056] The invention also relates to a component separation device. of a fluid medium, with constituents of interest to be recovered and contaminants to be eliminated, said separation device comprising, in a chamber, 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 chamber being connected, upstream of said separation device, taking into account the direction of flow of the fluid medium, to a supply line for the chamber in fluid medium and to a discharge line for the rejects, said chamber 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 chamber.
[0057] Other objects and advantages of the present invention will become apparent during the following description relating to embodiments which are given only by way of indicative and non-limiting examples.
[0058] Understanding this description will be facilitated by referring to the drawings attached in the appendix, in which:
[0059] [Fig.1] represents a schematic top view of a duct closure device known in the prior art.
[0060] [Fig. 2] shows a schematic front view of three rotor geometries that can be used in the shuttering device of [Fig. 1], or in any other shuttering device, the illustration on the left of [Fig. 2] representing a rotor with five blades or foils, the middle one a two-bladed rotor, while the one on the right shows a three-bladed rotor.
[0061] [Fig.3] illustrates, schematically and from the front, a first embodiment of a shutter device according to the invention.
[0062] [Fig.4] illustrates, schematically and from the front, a second embodiment of a shutter device according to the invention.
[0063] [Fig.5] illustrates, schematically and from the front, a third embodiment of a shutter device according to the invention.
[0064] [Fig.6] illustrates, schematically and from the front, a fourth embodiment of a shutter device according to the invention.
[0065] [Fig.7] illustrates, schematically and from the front, three more embodiments of a closure device according to the invention.
[0066] [Fig.8] schematically represents a shuttering device, according to the present invention, and corresponding to that illustrated on [Fig.6], intended to be integrated into an installation for separating the constituents of a fluid medium.
[0067] [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 - rpm) of the new shutter device of the invention, namely at 6.7 rpm or rpm, at 5.4 rpm or rpm and at 4 rpm or rpm.
[0068] [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-bladed shutter device whose geometry is similar to that illustrated on [Fig.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.
[0069] [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 obturating device of the invention (dark grey curve on the figure) and on the other hand with an old two-blade obturating device whose geometry is similar to that illustrated on [Fig.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.
[0070] 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.
[0071] 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.
[0072] Note that the medium whose constituents must be separated could just as easily consist of a solid medium or a gaseous medium.
[0073] 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.
[0074] 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.
[0075] The paper, in other words the cellulosic fibers which compose it, will indeed have to be purified to eliminate the undesirable constituents, such as have already been mentioned previously (glues, staples, ink, various plastic, metallic or mineral materials) in order to be able to be reused later for the manufacture of recycled paper.
[0076] 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.
[0077] The shutter device 1 of the present invention may also be used in the design of separation devices intended to be implemented in wastewater treatment plants, for the treatment of water, in order to separate polluting or non-polluting waste, in particular waste with a large size or bulk.
[0078] 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.
[0079] 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.
[0080] To return 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.
[0081] Thus, said at least one blade 4 corresponds to an annular portion 41 positioned preferably externally, but which can also be positioned internally, with respect to an internal circle 31 whose center corresponds to the axis of rotation 5 of the rotor shaft 3.
[0082] The rotation of the shaft by means of drive causes said at least one blade 4 to rotate, in a direction illustrated in the figures by an arrow, in this case in a counterclockwise direction, and said blade 4 comes, as it rotates, to open and close, alternately, the orifice 21 of said fluid supply nozzle 2.
[0083] The closing and then reopening of this orifice 21, cyclically, has the effect of creating, in the circuit of the installation at the level of which the obturating device 1 is positioned, pulsations of unclogging of a separation means, of the sieve type, also integrated in said installation.
[0084] 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.
[0085] 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, at the right of it.
[0086] 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.
[0087] Note that, although figures 3 to 7 of the accompanying 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.
[0088] 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.
[0089] In the following description, 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.
[0090] 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.
[0091] 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 [Fig. 7].
[0092] That being said, said closing front 6 may also consist of a curved shape, as seen in the attached [Fig.4].
[0093] 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 α with a radial line dl passing through the end 61 of said closing front 6 which is internal to the rotor 3 of the shutter device 1.
[0094] In the second case mentioned above, namely a closing front 6 of the blade 4 of curved shape, it is the line dBf passing, on the one hand, through the barycenter Bf of said curved shape constituting said closing front 6 and, on the other hand, through the internal end 61 of the rotor 3 of said closing front 6, which forms an angle a with the radial line dl passing through the end 61 of said closing front 6 which is internal to the rotor 3 of the shutter device 1.
[0095] As regards now 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.
[0096] 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 [Fig.7], while a curved opening front 7, in this case in the form of a semicircle, is illustrated in Figures 6 and 8.
[0097] In the first case, when said opening front 7 of the blade4 is made up of a straight line, the latter forms an angle [3 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.
[0098] When the opening front 7 of the blade 4 consists of a curved shape, it is the line dBo passing, on the one hand, through the barycenter Bo of the curved shape constituting said opening front 7 and, on the other hand, through the internal end 71 of the rotor 3 of said opening front, which forms an angle [3 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.
[0099] 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 have 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.
[0100] 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.
[0101] Indeed, by respecting this relationship with a>[3, the blade 4 will have to travel 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.
[0102] With reference now to [Fig.2] of the accompanying drawings, and also to [Fig.1], illustrating different rotor designs known from the prior art and which can be implemented in applications similar to those covered by the present application, it should be noted that the blades of each of these sealing devices have a symmetrical design.
[0103] In addition, the closing and opening fronts are globally radial with the axis of rotation of the rotor, as illustrated in particular in the attached [Fig.2], in particular in the illustration on the left.
[0104] Thus, at constant rotational speed of a rotor equipped with such blades, the speed of closure of an orifice by such a blade, when it passes over said orifice, is equal to the speed at which this orifice is then reopened.
[0105] 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 the same orifice 21 while allowing, on the other hand, a sufficiently long closing time of the orifice 21.
[0106] 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 located.
[0107] Consequently, the instantaneous flow rate of fluid through the feed nozzle 2 will be momentarily greater during the rapid reopening of its orifice 21, 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.
[0108] The depression thus generated will allow for effective unclogging of the sieve, in the aforementioned case.
[0109] According to a particular and preferred embodiment of the closing front 6 of said blade 4, which is shown in particular in Figures 3, 5 and 6 of the accompanying drawings, said closing front 6 consists of a straight line tangent to the inner circle 31 of the rotor 3 such that the angle α that said front 6 forms with the radial line dl is equal to 90
[0110] That being said, in other configurations, notably those shown in [Fig. 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 is understood that the angle a can also have a value less than 90°.
[0111] With reference now to [Fig.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.
[0112] Thus, in this aforementioned configuration, the angle a between the radial line dl and the line dBf 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°.
[0113] As regards 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 [3 is equal to 0. This possibility is illustrated in particular in Figures 3 and 4, and in the representation on the left of [Fig.7].
[0114] That being said, and as shown in [Fig.5] or in the middle and right illustrations of [Fig.7], the opening front 7 of the blade 4 can also consist of a straight line making an angle [3 > 0] with a radial line d2 passing through the axis of rotation 5 of the rotor 3.
[0115] 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 [Fig.6].
[0116] Thus, more particularly, 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.
[0117] 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.
[0118] 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.
[0119] The shutter device 1 having the characteristics of the present invention is particularly interesting.
[0120] It makes it possible to provide a robust system, and particularly simple to use, since the rotor 3 is rotated at a constant speed while allowing the opening speed of the nozzle 2 to be greater than its closing speed, by means of the asymmetry of the opening fronts 7 and closing fronts 6, while the duration during which said 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 said rotor 3 is rotated.
[0121] Thus, 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.
[0122] 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.
[0123] While maintaining a constant rotational 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.
[0124] Said shutter 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.
[0125] Note that the duration of a period (or cycle) using device 1 of the invention can be between 60 s and 2 s.
[0126] In addition, it could be estimated that said shutter device 1 could operate for more than 21,000,000 cycles without degradation of its performance.
[0127] Let us also recall here that said shutter device 1 is capable of handling heterogeneous flows, i.e. fluid, solid, or gaseous.
[0128] Thus, according to a particular application of the shutter device 1 of the invention, this is part of a device or a more overall 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 a fibrous suspension, with water and contaminants.
[0129] Such a separation device includes, in 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.
[0130] 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.
[0131] 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.
[0132] 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.
[0133] It is therefore conceivable that both the accepted and rejected lines are equipped with a shutter 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 shutter device 1 may also be positioned on the accepted line.
[0134] Fig. 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 said figure.
[0135] In order to illustrate the effect and interest of the shutter device 1 of the invention when incorporated in 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.
[0136] These tests will now be described with reference to the attached figures 9, 10 and 11.
[0137] 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 previously known prior art geometry, namely a two-bladed or bifoil rotor as shown in [Fig.2], leads to a decrease in the peak pressure measured in the accepted pipe of a component separation installation of a mixture.
[0138] Such a decrease in the pressure peak 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.
[0139] The sealing device 1 according to the invention makes it possible to solve this problem.
[0140] Indeed, it is visible, on the attached [Fig.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.
[0141] It can be deduced that the new rotor design makes it possible to reduce the rotational speed of the screening rotor, also called the screen rotor, which can be positioned, in particular, inside the sieve consisting of a cylindrical grid. Indeed, for the two-bladed rotor of the prior art, the rotational speed of the screen rotor has been reduced by 30%, namely the limiting speed below which clogging of the sieve occurs.
[0142] 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 appeared only at a lower rotation speed of the screen rotor.
[0143] 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.
[0144] Furthermore, it appears from the graph in [Fig.1 1] that, by means of the present shutter device 1, the closing time of the orifice 21 of the feed nozzle 2 is sufficient to reach the equilibrium pressure for the three speeds which have been tested here.
[0145] Indeed, for the three rotational speeds of the rotor 3 that were tested, and even for the highest rotational speed, namely 6.7 rpm, the pressure peak forms a plateau, which means that the equilibrium pressure has been reached. Then, this pressure drops sharply during the rapid opening made possible by the particular design of the blade opening face.
[0146] 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.
[0147] With reference now to [Fig.10], this allows comparison of the pressure peaks obtained in the accepted conduit 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).
[0148] 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.
[0149] The graph in [Fig. 10] illustrates that the presence of the two-bladed rotor in the installation produces a pressure peak, without however reaching a plateau.
[0150] 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.
[0151] The graph in [Fig.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 rpm) than a two-bladed rotor of the prior art, whose rotation speed is maintained only at 2 rpm or rpm.
[0152] 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
1.
2. Demands A shutter device (1) intended to close an orifice (21) of a fluid supply nozzle (2), particularly intended to be integrated into a device for separating the components of a fluid medium, said shutter device (1) consisting of 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) which, as it rotates, alternately opens and closes the orifice (21) of said supply nozzle (2) 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 constituted by the edge of said blade (4) that opens first during the closing of the nozzle (2), 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 (dBf) 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 (Bo) of the curved shape and the inner end to the rotor (71) of said opening front (7) of the blade (4), forming an angle α with a radial line (d2) passing through said inner end (71), with α greater than [3,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). 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. A shutter device (1) according to the preceding claim characterized in that said closure 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 [3 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 components of a fluid medium, with components of interest to be recovered and contaminants to be removed, said separation device comprising, within an enclosure, a separating element for said components, such as a sieve, adapted to allow the passage, downstream of said sieve, of the components 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 to the enclosure in fluid medium and to a refuse evacuation line, said enclosure being further connected, downstream of the separation device, to an outlet line for the accepted, said separation device being characterized in that it incorporates at least one shutter device (1) according to one of the preceding claims, positioned on at least one of the lines connected to said enclosure.