Fluidic oscillator and applications of the fluidic oscillator

Abstract

A fluidic component includes a flow chamber with at least one inlet opening and at least one outlet opening. The flow chamber can be traversed by a main flow of a fluid from the at least one inlet opening to the at least one outlet opening and includes at least one deflection device for the targeted change in direction of the main flow, in particular a periodic reversal of the main flow. The fluidic component includes at least one filter element between the deflection device for the targeted change in direction of the main flow and the flow chamber, in particular a deflection device for generating a varying approach flow direction for the main flow. The at least one filter element is not arranged upstream of the flow chamber or at the inlet opening of the flow chamber.

Claims

1. A fluidic component, comprising: a) a flow chamber with at least one inlet opening and at least one outlet opening, wherein the flow chamber can be traversed by a main flow of a fluid from the at least one inlet opening to the at least one outlet opening, b) at least one deflection device for the targeted change in direction of the main flow, and at least one filter element between the at least one deflection device for the targeted change in direction of the main flow and the flow chamber, wherein the at least one filter element is arranged downstream of the inlet opening of the flow chamber, so that only a part of the fluid stream passes the at least one filter element, wherein the at least one filter element is arranged along or parallel to one of several streamlines of the main flow, wherein each streamline represents a flow direction, and wherein the at least one filter element is arranged in a region of the fluid stream along or parallel to a streamline of the main flow, in which as compared to other streamlines or regions the main flow at least temporarily has a large flow velocity component substantially along and/or perpendicular to a basic direction of the main flow.

2. The fluidic component according to claim 1, wherein the at least one deflection device for the targeted change in direction of the main flow includes a feedback channel, is formed as feedback channel or is formed as a closed cavity.

3. The fluidic component according to claim 1, wherein in operation the at least one filter element between the flow chamber and the at least one deflection device for the targeted change in direction of the main flow is exposed to a flow with changing flow direction.

4. The fluidic component according to claim 1, wherein the at least one filter element is arranged at a position between the flow chamber and the at least one deflection device for the targeted change in direction of the main flow, at which the fluid changes its flow velocity transversely to the main flow maximally.

5. The fluidic component according to claim 1, wherein the at least one filter element is arranged at a position between the flow chamber and the at least one deflection device for the targeted change in direction of the main flow, at which the cross-section, which is effective for the flow, of the flow chamber or of the at least one deflection device for the targeted change in direction of the main flow is minimal.

6. The fluidic component according to claim 1, wherein the at least one filter element is arranged at an opening of the at least one deflection device for the targeted change in direction of the main flow.

7. The fluidic component according to claim 1, wherein the at least one filter element is arranged in a mental continuation of a portion of the flow chamber at a position between the flow chamber and the at least one deflection device for the targeted change in direction of the main flow.

8. The fluidic component according to claim 1, wherein the at least one filter element is formed cylindrical, conical, rectangular, triangular, pyramid-shaped, oval-shaped, round or polygonal.

9. The fluidic component according to claim 1, wherein the at least one filter element includes a lattice structure and/or a net.

10. The fluidic component according to claim 1, wherein in operation the at least one filter element is subject to a self-cleaning effect due to a changing flow direction.

11. The fluidic component according to claim 1, comprising a non-stick coating.

12. The fluidic component according to claim 1, wherein the at least one filter element is formed at least partly flexible and/or elastically deformable.

13. An apparatus with a fluidic component according to claim 1, wherein the apparatus is at least one of the following apparatuses: a household appliance / industrial appliance or commercial appliance comprising: a rinsing machine; a dishwashing appliance; a washing machine; a steam cleaning appliance; a steam cooker; a convection oven; a pasteurizing system; a tumble dryer; an appliance with steam function; a sterilizing system; or a disinfection system; a cleaning appliance comprising: a high-pressure cleaner; a low-pressure cleaner; a washing line; a spray cleaning system; a descaling system; or a de-icing system; an irrigation device comprising: agriculture and agricultural technology; or a distribution of plant protection agents; a blasting technology device comprising: a shot peening method; a CO.sub.2, snow or dry ice blasting; a blasting with mineral media; or a compressed-air blasting; a surface treatment device comprising: a painting facility; or an electroplating facility; a whirlpool; a mixing system comprising: a combustion device; an internal combustion engine; a heating system; an injection system; a mixing facility; or a bio/chemical reactor; a cooling system; an extinguishing system; or a water treatment system.

14. The fluidic component according to claim 1, wherein the at least one deflection device for the targeted change in direction of the main flow is a deflection device for generating a varying approach flow direction for the main flow and wherein the at least one filter element is arranged between the at least one deflection device for generating a varying approach flow direction for the main flow and the flow chamber.

15. The fluidic component according to claim 1, wherein the at least one deflection device for the targeted change in direction of the main flow is configured to effect a periodic reversal of the main flow.

16. The fluidic component according to claim 6, wherein the at least one filter element is arranged only at an inlet, only at an outlet, or at the inlet and the outlet of the at least one deflection device for the targeted change in direction of the main flow.

17. The fluidic component according to claim 11, wherein the non-stick coating is on the at least one filter element.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will be explained in detail below by means of several exemplary embodiments with reference to the Figures, in which:

(2) FIG. 1 in the sub-images a), b) and c) schematically shows three known fluidic components with additional flow channels and integrated filter elements each in the region of the inlet opening of each fluidic component;

(3) FIG. 2 in the sub-images a), b) and c) schematically shows three known fluidic components with integrated filter elements each in the region of the inlet opening of each fluidic component;

(4) FIG. 3 shows a flow simulation for the fluidic component of FIG. 4, wherein in sub-image a) the velocity distribution and in sub-image b) the velocity distribution and the flow lines are shown;

(5) FIG. 4 shows a schematic representation of a fluidic component according to an embodiment of the invention;

(6) FIG. 5 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(7) FIG. 6 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(8) FIG. 7 shows three snapshots (images a) to c)) within an oscillation cycle of a fluid stream to illustrate the position of the filter elements of the fluidic component of FIG. 4 with respect to the main flow, the secondary flow and the recirculation areas;

(9) FIG. 8 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(10) FIG. 9 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(11) FIG. 10 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(12) FIG. 11 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(13) FIG. 12 shows three schematic representations of fluidic components according to further embodiments of the invention;

(14) FIG. 13 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(15) FIG. 14 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(16) FIG. 15 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(17) FIG. 16 shows a schematic representation of a fluidic component according to a further embodiment of the invention;

(18) FIG. 17 shows two schematic representations of fluidic components according to further embodiments of the invention;

(19) FIG. 18 shows a schematic representation of a fluidic component according to a further embodiment of the invention; and

(20) FIG. 19 shows a schematic representation of a fluidic component according to a further embodiment of the invention; and

(21) FIG. 20 shows three snapshots (images a) to c)) of an oscillation cycle of a fluid stream to illustrate the flow direction of the fluid stream which flows through the fluidic component of FIG. 4.

DESCRIPTION OF THE INVENTION

(22) FIGS. 1 and 2 show various fluidic components which are known from the prior art. The fluidic component of FIG. 1, sub-image a), is disclosed in U.S. Pat. No. 8,702,020 B2, the fluidic components of FIG. 1, sub-images b) and c), and of FIG. 2, sub-image b), in EP 1 053 059 B1, the fluidic component of FIG. 2, sub-image a), in EP 1 513 711 B1, and the fluidic component of FIG. 2, sub-image c), in EP 2 102 922 B1.

(23) The fluidic components generally are designated with the reference numeral 1. The fluidic components 1 each include a flow chamber MC which can be traversed by a (particle-loaded) fluid. The fluid enters into the flow chamber MC via an inlet opening PN and again exits from the flow chamber MC via an outlet opening EX. The fluidic components 1 of FIG. 1 each include two feedback channels FC as means for the targeted change in direction of the main flow of the fluid stream. The fluidic components 1 of FIG. 2 each include two collision channels as means for the targeted change in direction of the main flow of the fluid stream, which are aligned with each other such that the streams exiting from the collision channels collide with each other, so as to generate an oscillation.

(24) In the region of the inlet opening PN of the fluidic components 1 of FIGS. 1 and 2 filter elements FE each are arranged for filtering particles with which the fluid entering into the fluidic components 1 might be loaded. The filter elements FE have different shapes and arrangements. The fluidic components 1 of FIGS. 1 and 2, however, have in common that the filter elements FE always are arranged such that the entire fluid must pass the filter elements FE, in order to be able to reach the outlet opening.

(25) In the following, various embodiments of the invention will be described with reference to FIGS. 3 to 19.

(26) FIG. 4 shows a fluidic component 1 according to an embodiment of the invention. In sub-image a), FIG. 3 shows the velocity distribution of a fluid stream which traverses the fluidic component 1 of FIG. 4. In sub-image b) of FIG. 3 the flow lines of the fluid stream are shown in addition.

(27) The fluidic component 1 of FIG. 4 comprises a flow chamber MC which can be traversed by a fluid stream 10, 20 (FIGS. 3, 7 and 20). The flow chamber MC also is referred to as interaction chamber.

(28) The flow chamber MC comprises an inlet opening PN via which the fluid stream enters into the flow chamber MC, and an outlet opening EX via which the fluid stream exits from the flow chamber MC. The inlet opening PN and the outlet opening EX are arranged on two opposite sides of the fluidic component 1. In the flow chamber MC the fluid stream substantially moves along a longitudinal axis A of the fluidic component 1 (which connects the inlet opening PN and the outlet opening EX with each other) from the inlet opening PN to the outlet opening EX.

(29) The longitudinal axis A forms an axis of symmetry of the fluidic component 1. The longitudinal axis A is the intersection line of two planes of symmetry vertical to each other, with respect to which the fluidic component 1 is mirror-symmetrical. One of the planes of symmetry is parallel to the drawing plane of FIG. 4. Alternatively, the geometry of the fluidic component 1 cannot be of the symmetrical (mirror-symmetrical) or axially symmetrical type.

(30) For the targeted change in direction of the fluid stream, two secondary flow channels (feedback channels) FC are provided beside the flow chamber MC, wherein the flow chamber MC (as seen transversely to the longitudinal axis A) is arranged between the two secondary flow channels FC. Alternatively, only one secondary flow channel or more than two secondary flow channels can also be provided. Directly behind (downstream of) the inlet opening PN the two secondary flow channels FC branch off from the flow chamber MC. Directly before (upstream of) the outlet opening EX, they are then joined again.

(31) The two secondary flow channels FC are symmetrically arranged with respect to the longitudinal axis A. According to a non-illustrated alternative, the secondary flow channels are not arranged symmetrically.

(32) The flow chamber MC substantially linearly connects the inlet opening PN and the outlet opening EX with each other, so that the fluid stream flows substantially along the longitudinal axis A of the fluidic component 1. In a first portion, the secondary flow channels FC extend in opposite directions proceeding from the inlet opening PN each initially at an angle of substantially 90 to the longitudinal axis A. Subsequently, the secondary flow channels FC turn off, so that they each extend (second portion) substantially parallel to the longitudinal axis A (in direction of the outlet opening EX). To again join the secondary flow channels FC and the flow chamber MC, the secondary flow channels FC at the end of the second portion again change their direction, so that they are each directed substantially in direction of the longitudinal axis A (third portion). In the embodiment of FIG. 4, the direction of the secondary flow channels FC changes by an angle of about 120 on transition from the second into the third portion. However, for the change in direction other angles than the one mentioned here can also be chosen between these two portions of the secondary flow channels FC.

(33) The secondary flow channels FC are a means for influencing the direction of the fluid stream which flows through the flow chamber MC. The secondary flow channels FC therefor each include an inlet 6a, 6b which is formed by the end of the secondary flow channels FC facing the outlet opening EX, and each an outlet 8a, 8b which is formed by the end of the secondary flow channels FC facing the inlet opening PN. Through the inlets 6a, 6b a small part of the fluid stream, the secondary flow 20 (FIG. 20), flows into the secondary flow channels FC. The remaining part of the fluid stream (the so-called main flow 10) exits from the fluidic component 1 via the outlet opening EX (FIG. 20). In FIG. 20, the exiting fluid stream is designated with the reference numeral 15. At the outlets 8a, 8b the secondary flows 20 exit from the secondary flow channels FC, where they can exert a lateral (transversely to the longitudinal axis A) impulse on the fluid stream entering through the inlet opening PN. The direction of the fluid stream is influenced such that the fluid stream 15 exiting at the outlet opening EX spatially oscillates, namely in the plane in which the flow chamber MC and the secondary flow channels FC are arranged. FIG. 20, which shows the oscillating fluid stream, will be explained in detail later on.

(34) The secondary flow channels FC each have a cross-sectional area which is almost constant along the entire length (from the inlet 6a, 6b to the outlet 8a, 8b) of the secondary flow channels FC. On the other hand, the size of the cross-sectional area of the flow chamber MC steadily increases in flow direction of the main flow 10 (i.e. in the direction from the inlet opening PN to the outlet opening EX), wherein the shape of the flow chamber MC is mirror-symmetrical to the two planes of symmetry.

(35) The flow chamber MC is separated from each secondary flow channel FC by a block 11a, 11b. In the embodiment of FIG. 4, the two blocks 11a, 11b are identical in shape and size and are arranged symmetrically with respect to the longitudinal axis A. In principle, however, they can also be formed differently and be aligned non-symmetrically. In the case of a non-symmetrical alignment the shape of the flow chamber MC also is non-symmetrical. The shape of the blocks 11a, 11b, which is shown in FIG. 4, only is an example and can be varied. The blocks 11a, 11b of FIG. 4 have rounded edges.

(36) At the inlet 6a, 6b of the secondary flow channels FC there are also provided separators 105a, 105b in the form of indentations. At the inlet 6a, 6b of each secondary flow channel FC an indentation 105a, 105b each protrudes beyond a portion of the circumferential edge of the secondary flow channel FC into the respective secondary flow channel FC and at this point changes its cross-sectional shape by reducing the cross-sectional area. In the embodiment of FIG. 4 the portion of the circumferential edge is chosen such that each indentation 105a, 105b (among other things also) is directed to the inlet opening PN (aligned substantially parallel to the longitudinal axis A). Alternatively, the separators 105a, 105b can be oriented differently. The separation of the secondary flows 20 from the main flow 10 is influenced and controlled by the separators 105a, 105b. By the shape, size and orientation of the separators 105a, 105b the quantity which flows from the fluid stream into the secondary flow channels FC as well as the direction of the secondary flows 20 can be influenced. This in turn leads to an influence on the exit angle of the exiting fluid stream 15 at the outlet opening EX of the fluidic component 1 (and hence to an influence on the oscillation angle) as well as the frequency at which the exiting fluid stream 15 oscillates at the outlet opening EX. By choosing the size, orientation and/or shape of the separators 105a, 105b the profile of the fluid stream 15 exiting at the outlet opening EX thus can be influenced in a targeted way. Alternatively, a separator can also be provided only at the inlet of one of the two secondary flow channels.

(37) Upstream of the inlet opening PN a funnel-shaped attachment 106 is provided, which tapers in direction of the inlet opening PN (downstream). The flow chamber MC also tapers, namely in the region of the outlet opening EX. The taper is formed by an outlet channel 107 which extends between the separators 105a, 105b and the outlet opening EX. The funnel-shaped attachment 106 and the outlet channel 107 taper such that only their width (i.e. their extension in the drawing plane in FIG. 4 vertically to the longitudinal axis A) each decreases in downstream direction. The taper has no influence on the depth (i.e. the extension vertically to the drawing plane in FIG. 4) of the attachment 106 and of the outlet channel 107. Alternatively, the attachment 106 and the outlet channel 107 also can each taper in terms of width and depth. Furthermore, only the attachment 106 can taper in terms of depth or width, while the outlet channel 107 tapers both in terms of width and in terms of depth, and vice versa. The extent of the taper of the outlet channel 107 influences the directional characteristic of the fluid stream 15 exiting from the outlet opening EX and thus its oscillation angle. In FIG. 4, the shape of the funnel-shaped attachment 106 and the outlet channel 107 only are shown by way of example. Here, their width each decreases linearly in downstream direction. Other shapes of the taper are possible.

(38) In the region of the inlets 6a, 6b and the outlets 8a, 8b of the secondary flow channels FC filter elements FE each are arranged. In the region of the inlets 6a, 6b the filter elements FE extend before the separators 105a, 105b as seen in flow direction of the secondary flows. In FIG. 4 broken lines are depicted schematically, which indicate a substantially linear arrangement of individual filter elements FE in each inlet and outlet region 6a, 6b, 8a, 8b. Not every point of the broken lines necessarily corresponds to a filter element FE. Rather, the broken lines merely show the basic course (linear in the exemplary embodiment of FIG. 4) of the filter elements FE. The filter elements FE extend over the entire component depth. The filter elements FE are arranged at a distance from the blocks 11a, 11b and from the side walls of the flow chamber MC and the secondary flow channels FC. A filter element assembly (a group of filter elements) extends across the entire width of the secondary flow channels FC, but can also be less broad. The filter element assemblies extend substantially transversely (which does not necessarily mean an angle of 90) to the flow direction of the secondary flows 20. The shape, size and number of the filter elements FE can be chosen according to various criteria. For example, the type of the fluid as well as the quantity, shape and size of the particles with which the fluid is loaded can influence the shape, size and number of the filter elements FE. Preferably, the distance between the filter elements FE in the inlet regions 6a, 6b is smaller than the distance between the filter elements FE in the outlet regions 8a, 8b. Alternatively, the filter elements FE only are provided in the inlet regions 6a, 6b and not in the outlet regions 8a, 8b.

(39) The filter elements FE can be positioned according to a mental continuation of the lateral walls 4a, 4b of the blocks 11a, 11b (or of the flow chamber MC). In contrast to the illustrated filter position, the filter elements FE also can be positioned along the streamlines obtained in the flow situation in which the main flow attaches to one of the lateral walls 4a, 4b of the blocks 11a, 11b (or of the flow chamber MC). Furthermore, the filter elements FE can be arranged in the region of the inlet 6a, 6b of the secondary flow channel FC and/or in the region of the outlet 8a, 8b of the secondary flow channel FC at a position in which the largest flow velocity components (of the main flow) occur, which alternately are located along and transversely to the main flow. The skilled person can determine this position by means of the usual methods known from the prior art for a fluidic component without filter elements. It is also possible to position the filter elements FE in the region of the narrowest cross-section of the secondary flow channels FC. In fluidic components with a separator 105a, 105b this position frequently is located between the separator 105a, 105b and the block 11a, 11b which separates the flow chamber from the secondary flow channel FC.

(40) FIG. 20 shows three snapshots of a fluid stream to illustrate the flow direction (streamlines) of the fluid stream in the fluidic component 1 of FIG. 4 during an oscillation cycle (images a) to c)). In the images a) and c) the streamlines are shown for two deflections of the exiting fluid stream 15, which approximately correspond to the maximum deflections. The angle swept by the exiting fluid stream 15 between these two maxima is the oscillation angle (FIG. 20). Image b) shows the streamlines for a position of the exiting fluid stream 15, which approximately lies in the middle between the two maxima of images a) and c). In the following, the flows within the fluidic component 1 during an oscillation cycle will be described. There will be used the terms upper secondary flow channel and lower secondary flow channel. The same merely relate to the relative arrangement of the two secondary flow channels in FIG. 4 (not to a necessarily required arrangement) and serve the better understanding.

(41) First of all, the pressurized fluid stream is conducted into the fluidic component 1 via the inlet opening PN. In the region of the inlet opening PN the fluid stream hardly experiences a pressure loss, as it can flow into the flow chamber MC undisturbed. The main flow 10 of the fluid stream initially flows along the longitudinal axis A in direction of the outlet opening EX (image a)).

(42) By introducing a one-time accidental or targeted disturbance, the fluid stream is deflected laterally in direction of the side wall of the one block 11a facing the flow chamber MC, so that the direction of the fluid stream increasingly deviates from the longitudinal axis A, until the fluid stream is maximally deflected. Due to the so-called Coanda effect, the largest part of the fluid stream, the so-called main flow 10, attaches to the side wall of the one block 11a and then flows along this side wall. In the region between the main flow 10 and the other block 11b a recirculation area 30 is formed. The recirculation area 30 grows, the more the main flow 10 attaches to the side wall of the one block 11a. The main flow 10 exits from the outlet opening EX at an angle changing over time with respect to the longitudinal axis A. In FIG. 20a) the main flow 10 attaches to the side wall of the one block 11a and the recirculation area 30 facing the block 11b has its maximum size. In addition, the fluid stream 15 exits from the outlet opening EX with approximately the largest possible deflection.

(43) A small part of the fluid stream, the so-called secondary flow 20, separates from the main flow 10 and flows into the secondary flow channels FC via their inlets 6a, 6b. In the situation shown in FIG. 20a) the part of the fluid stream, which flows into the secondary flow channel FC adjoining the block 11b to whose side wall the main stream 10 does not attach, is distinctly larger (due to the deflection of the fluid stream in direction of the block 11a) than the part of the fluid stream which flows into the secondary flow channel FC adjoining the block 11a, to whose side wall the main flow 10 attaches. In FIG. 20a) the secondary flow 20 in the upper secondary flow channel FC hence is distinctly larger than the secondary flow 20 in the lower secondary flow channel FC, which almost is negligible. In general, the deflection of the fluid stream into the secondary flow channels FC can be influenced and controlled by means of separators. The secondary flows 20 (in particular the secondary flow 20 in the lower secondary flow channel FC) flow through the secondary flow channels FC to their respective outlets 8a, 8b and hence provide an impulse to the fluid stream entering at the inlet opening PN. As the secondary flow 20 in the lower secondary flow channel FC is larger than the secondary flow 20 in the upper secondary flow channel FC, the impulse component resulting from the secondary flow 20 in the lower secondary flow channel FC is predominant.

(44) The main flow 10 hence is pressed against the side wall of the block 11a due to the impulse (of the secondary flow 20 in the lower secondary flow channel FC). At the same time, the recirculation area 30 facing the block 11b moves in direction of the inlet 8b of the lower secondary flow channel FC, whereby the supply of fluid into the lower secondary flow channel FC is disturbed. The impulse component resulting from the secondary flow 20 in the lower secondary flow channel FC hence decreases. At the same time, the recirculation area 30 facing the block 11b is reduced in size, while a further (growing) recirculation area 30 is formed between the main flow 10 and the side wall of the block 11a. The supply of fluid into the upper secondary flow channel FC also increases. The impulse component resulting from the secondary flow 20 in the upper secondary flow channel FC hence increases. The impulse components of the secondary flows 20 in the further course more and more approach each other, until they are of equal size and cancel each other out. In this situation the entering fluid stream is not deflected, so that the main flow 10 moves approximately centrally between the two blocks 11a, 11b and a fluid stream 15 exits from the outlet opening EX almost without deflection. FIG. 20b) does not show exactly this situation, but a situation shortly before the same.

(45) In the further course, the supply of fluid into the upper secondary flow channel FC increases more and more, so that the impulse component resulting from the secondary flow 20 in the upper secondary flow channel FC exceeds the impulse component resulting from the secondary flow 20 in the lower secondary flow channel FC. The main flow 10 thereby is urged away more and more from the side wall of the block 11a, until it attaches to the side wall of the opposed block 11b due to the Coanda effect (FIG. 20c)). The recirculation area 30 which faces the block 11b thereby is dissolved, while the recirculation area 30 which faces the block 11a grows to its maximum size. The main flow 10 now exits from the outlet opening EX with maximum deflection, which as compared to the situation of FIG. 20a) has an inverse sign.

(46) Subsequently, the recirculation area 30 which faces the block 11a will travel and block the inlet 6a of the upper secondary flow channel FC, so that the supply of fluid here decreases again. In the following the secondary flow 20 in the lower secondary flow channel FC will provide the dominant impulse component, so that the main flow 10 again is pressed away from the side wall of the block 11b. The described changes now take place in reverse order.

(47) Due to the construction of the fluidic component and the described process, the fluid stream 15 exiting at the outlet opening EX oscillates about the longitudinal axis A in a plane in which the flow chamber MC and the secondary flow channels FC are arranged, so that a fluid jet cyclically sweeping to and fro is generated. To achieve the described effect, a symmetrical construction of the fluidic component 1 is not absolutely necessary.

(48) FIG. 3 in the sub-images a) and b) each shows a snapshot of the transient flow process within the fluidic component 1 of FIG. 4, wherein in both sub-images the time of taking the shot is the same. The velocity of the fluid stream within the fluidic component is coded by grey scales. The velocity field within the fluidic component represents the normalized velocity of the fluid stream in main flow direction (from the inlet opening PN to the outlet opening EX) with the maximum velocity in main flow direction. The color black corresponds to the normalized velocity u/u.sub.max 0 and the color white corresponds to the normalized velocity u/u.sub.max 1 and thus to the maximum velocity in main flow direction.

(49) In sub-image b) of FIG. 3 flow lines also are shown for additional visualization. Between the outlet opening EX and the filter elements FE at the inlet 6b of the secondary flow channel FC on the right in FIG. 3a region can be seen, where a streamline forms a closed curve (recirculation area). In this current flow situation, transverse forces act on the filter elements FE or the flow here has high transverse components with respect to the main flow direction. Due to the oscillation mechanism, the recirculation area shown in FIG. 3 is dissolved, wherein another recirculation area is obtained between the outlet opening EX and the filter elements FE at the inlet 6a of the secondary flow channel FC on the left in FIG. 3. Due to this dynamic the individual filter elements FE alternately are approached transversely with respect to the main flow direction. This flow situation ensures that particles possibly adhering to a filter element FE again are conveyed in direction of the main flow and then are entrained by the main flow. The self-cleaning effect of the fluidic component can be achieved thereby.

(50) In sub-images a) to c) FIG. 7 shows three snapshots during an oscillation cycle. Not all streamlines are shown here, but only streamlines with high flow velocity. In principle, the filter elements FE can be cleaned by the main flow 10 (at the inlet 6a, 6b), the secondary flow 20 (at the outlet 8a, 8b) and by the constantly changing recirculation areas (30 (at the inlet 6a, 6b). Sub-images b) and c) by way of example show how recirculation areas 30 move along the filter elements FE at the inlet 6a, 6b of the feedback channels FC and in doing so change their shape. A filtered foreign object experiences a force acting on the same from different directions. This force can ensure that the foreign object again is released and is then discharged by the main flow 10 or by the recirculation area 30 itself. Foreign objects which are filtered at the outlet 8a, 8b of the feedback channels FC can be removed by the secondary flow 20, which exits from the feedback channel FC. Therefore, a larger distance of the filter elements FE can be provided in the outlet region 8a, 8b than in the inlet region 6a, 6b, so that foreign objects which could flow through the filter elements FE in the inlet region 6a, 6b also can leave the feedback channel FC.

(51) The fluidic component of FIG. 4 can also be regarded as fluidic oscillator, wherein the (one-time) targeted change in direction of the main flow 10 leads to an oscillation of the main flow 10 in the flow chamber MC and of the exiting fluid stream 15. The fluidic component 1 of FIG. 4 cannot lose its function despite particles or foreign objects with which the fluid traversing the fluidic component 1 is loaded. Another positive side effect consists in that the pressure loss in the fluidic component of FIG. 4 is smaller as compared to the known fluidic components with filter elements FE, which are located near the inlet region PN (FIGS. 1 and 2), as in the known construction the entire fluid stream must flow through the filter elements FE.

(52) By the filter elements FE a cross-sectional constriction can be created at the inlet 6a, 6b of the feedback channels FC and/or at the outlet 8a, 8b of the feedback channels FC. The filter elements hence can be formed by individual bodies spaced from each other, whereby a reduction of the cross-section of the feedback channels FC is generated, in order to achieve a filter function. The individual (filter) bodies can have a distance to each other which is not so small that no more fluid can get through and/or not so large that no more filter effect is achieved. By the filter elements FE in the region of the feedback channels FC it is prevented that a larger amount of particles or foreign objects can penetrate into the feedback channels FC. Thus, the deposition of foreign objects in the feedback channels FC is reduced or prevented. This risk of the deposition in the feedback channels FC would exist without the filter elements, as the flow velocity in a feedback channel FC mostly is considerably smaller than the flow velocity in the flow chamber MC. The foreign objects thus might settle in the feedback channels and might not be flushed away.

(53) By an arrangement of the filter elements FE for example in the region of a flow with a periodic change in direction, the fluid can clean the filter elements FE on its own. By a recirculation area 30 (at the inlet of a secondary flow channel) and/or by the secondary flow 20 (at the outlet of the secondary flow channel) the particles or deposits are released from the filter element FE, which can then be transported away with the main flow 10.

(54) The fluidic component 1 of FIG. 5 differs from that of FIG. 4 in particular by the arrangement of the filter elements FE. Here as well, filter elements FE each are arranged in the region of the inlets 6a, 6b and the outlets 8a, 8b of the secondary flow channels FC. However, the filter elements FE in FIG. 5 are not arranged in a straight line (linearly), but each follow a curved path (broken lines in FIG. 5). The path at the two inlets 6a, 6b and at the two outlets 8a, 8b each is mirror-symmetrical, wherein the path at the inlets 6a, 6b differs from the path at the outlets 8a, 8b. The filter elements FE at the inlets 6a, 6b as seen in flow direction of the secondary flows 20 (i.e. in direction from an inlet 6a, 6b to the corresponding outlet 8a, 8b) are arranged according to a concave curvature, and the filter elements FE at the outlets 8a, 8b as seen in flow direction of the secondary flows 20 are arranged according to a convex curvature. The radii of curvature of the convex and the concave curvature are different and in FIG. 5 only shown by way of example. Depending on the case of application (type of fluid (for example viscosity, density, surface tension, temperature), type (size, shape, deformability) and quantity of the particles) the radii of curvature can be chosen differently. For example, at both inlets 6a, 6b and at both outlets 8a, 8b the radii of curvature can be identical or each be different (for example in the case of a non-symmetrical design of the fluidic component). Moreover, all curvatures can be convex or concave.

(55) FIG. 6 shows further examples for the course of the filter elements FE. The fluidic component 1 of FIG. 6 likewise differs from the one of FIG. 4 in particular by the arrangement of the filter elements FE. The filter elements FE at the inlets 6a, 6b as seen in flow direction of the secondary flows 20 (i.e. in direction from an inlet 6a, 6b to the corresponding outlet 8a, 8b) each are arranged according to a convex curvature, wherein the two convex curvatures however differ from each other. As seen in flow direction of the secondary flows 20, the filter elements FE at the outlet 8a are arranged according to a concave curvature. The filter elements FE at the outlet 8b are arranged according to a zigzag line. Further geometries for the arrangement of the filter elements FE are imaginable. Depending on the case of application (type of fluid (for example viscosity, density, surface tension, temperature), type (size, shape, deformability) and quantity of the particles) different geometries can be chosen. The geometry for the arrangement of the filter elements FE for example is chosen such that the filter elements FE extend along the streamlines of the fluid stream.

(56) FIGS. 8 and 10 show two more embodiments of the fluidic component 1. These two embodiments differ from that of FIG. 4 in particular by the fact that in the outlet channel 107a flow divider (also called splitter) 3 is provided. At the inlets 6a, 6b of the secondary flow channels FC of the fluidic component 1 of FIG. 8 no separator is provided. In FIG. 10, the separators 105a, 105b (as compared to the embodiment of FIG. 4) have a shape pointed in direction of the inlet opening PN. The shape of the blocks 11a, 11b also is different from the shape as shown in FIG. 4. The basic geometrical properties of these two embodiments however correspond with those of the fluidic component 1 of FIG. 4.

(57) The flow divider 3 each has the shape of a triangular wedge which broadens in fluid flow direction. The outlet channel 107 also broadens in fluid flow direction. The wedge has a depth which corresponds to the component depth. (The component depth is constant over the entire fluidic component 1). The flow divider 3 hence divides the outlet channel 107 in two sub-channels with two outlet openings EX and the fluid stream in two sub-streams which exit from the fluidic component 1. Due to the oscillation mechanism described in connection with FIG. 4, the two sub-streams exit from the two outlet openings EX in a pulsed manner.

(58) In the embodiment of FIG. 8, the flow divider 3 substantially extends in the outlet channel 107, whereas in the embodiment of FIG. 10 it protrudes into the flow chamber MC. In principle, the shape and size of the flow divider 3 can freely be chosen depending on the desired application. There can also be provided several flow dividers (transversely to the longitudinal axis A in the oscillation plane or also transversely to the oscillation plane of the fluid stream), in order to divide the exiting fluid jet into more than two sub-streams.

(59) FIGS. 8 and 10 also show two more embodiments for the blocks 11a, 11b. However, these shapes only are to be understood by way of example and not exclusively in connection with the flow divider 3. When using a flow divider 3, the blocks 11a, 11b also can be formed differently. The blocks 11a, 11b of FIG. 8 have a substantially trapezoidal basic shape, which tapers in downstream direction (in its width) and from whose ends a triangular protrusion each projects into the flow chamber MC. The blocks 11a, 11b of FIG. 10 resemble those of FIG. 4, but have no rounded corners.

(60) In FIGS. 8 and 10 (like also in FIG. 4) the filter elements FE are arranged along a straight line (broken line) in the region of the inlets 6a, 6b and the outlets 8a, 8b of the secondary flow channels FC.

(61) The fluidic component of FIG. 9 corresponds to the one of FIG. 10 and in particular differs from the latter in that no flow divider is provided.

(62) Another embodiment of the invention is shown in FIG. 11. In this embodiment, the secondary flow channels FC are separated from the flow chamber MC by the blocks 11a, 11b, wherein the blocks 11a, 11b are substantially rectangular and each include a triangular protrusion which at the end of the blocks 11a, 11b facing the inlet opening PN projects into the flow chamber MC. Hence, the flow chamber (with the exception of the region in which the triangular protrusions are formed) has a substantially constant width. Due to the shape of the blocks 11a, 11b the individual portions of the secondary flow channels FC extend substantially parallel or vertically to the flow chamber MC. Separators are not provided in the embodiment of FIG. 11. In the region of the inlets 6a, 6b of the secondary flow channels FC filter elements FE are provided, which each are arranged along a curved line. As see in flow direction of the secondary flows 20 (i.e. in direction from an inlet 6a, 6b to the corresponding outlet 8a, 8b) the line is arranged according to a convex curvature. In the region of the outlets 8a, 8b of the secondary flow channels FC filter elements FE are provided, which each are arranged along a straight line. The filter element assemblies extend substantially transversely (which does not necessarily mean an angle of 90) to the flow direction of the secondary flows 20.

(63) In FIGS. 12 to 19 various known fluidic components are shown, which additionally include filter elements FE. According to the invention, the filter elements FE are arranged at the inlets and outlets of the secondary flow channels FC (FIGS. 12-17, 19). In FIG. 15, the secondary flow channel FC is short-circuited. Thus, an opening of the secondary flow channel acts as inlet and outlet in temporal alternation. In a first step, the upper opening of the secondary flow channel FC shown in FIG. 15 for example is an inlet, and thus the lower opening of the secondary flow channel FC shown in FIG. 15 is an outlet, namely until the (main) flow is pressed onto the other wall side of the flow chamber MC. Thereafter, the respective openings swap their function.

(64) In FIG. 17, sub-image b), several feedback channels FC are provided. The feedback channel FC in the region of the outlet opening EX intensifies the temporal pulsation, but here does not act as a means for changing the main flow direction. The filter elements FE secure the function of the additional feedback channel FC.

(65) In FIG. 18 a closed cavity SK is provided as means for the targeted change in direction of the main flow. In this exemplary embodiment the inlet of the closed cavity SK at the same time is the outlet of the closed cavity SK. The filter elements FE are arranged in the inlet/outlet region of the closed cavity SK.

(66) The fluidic components of FIGS. 12 to 19 without filter elements (or with filter elements in the region/downstream of the inlet opening of the fluidic components) are known from the following disclosures: EP 1 053 059 B1 (FIG. 12, sub-images a) and b)), WO 80/00927 (FIG. 12, sub-image c), FIG. 13), EP 1 658 209 B1 (FIG. 14), DE 2 051 804 (FIG. 15), DE 2 414 970 (FIG. 16), U.S. Pat. No. 8,733,401 B2 (FIG. 17, sub-images a) and b)), Review of some fluid oscillators, Harry Diamond Laboratories, Washington, 1969 (FIG. 18), A review of Fluidic Oscillator Development and Application for Flow Control, 43rd Fluid Dynamic Conference, 24-27 Jun. 2013.

(67) The fluidic component (1) according to the invention is suitable for fluids loaded or contaminated with particles or foreign objects, wherein despite the particles or foreign objects, which penetrate into the fluidic component, it maintains its function (formation of an oscillating fluid stream) and is not clogged by the particles. The fluidic component (1) according to the invention additionally has a self-cleaning effect, as the filter elements are again flushed free by the (pressurized) fluid. Thus, the filter elements FE can be cleaned by the main flow 10, the secondary flow 20 and by the constantly changing recirculation areas 30. The changing direction of the main flow 10 and in particular of the recirculation areas 30 during the oscillation process correspondingly rinses and cleans the filter elements FE. A filtered foreign object thus experiences a force acting from different directions. This force can ensure that the foreign object again is released and is then discharged by the main flow 10 or by a recirculation area 30. This effect is pronounced very much in particular at the inlet 6a, 6b of the feedback channels FC (cf. FIG. 7). Foreign objects which are filtered in the outlet region 8a, 8b of the feedback channels FC can be removed by the secondary flow 20.

(68) The presence of the filter elements only causes a minor pressure loss, as in essence only the secondary flow must flow through the cross-sectional constriction. The fluidic component has an increased service life, as the integrated filter elements (and the secondary flow channels or closed cavities) are not clogged. Furthermore, due to the arrangement of the filter elements according to the invention the costs and complexity are reduced as compared to systems with upstream filter systems (arranged upstream of the inlet opening of the fluidic components).

(69) The fluidic component according to the invention is suitable for every field of application working with fluids. For example, the fluidic component according to the invention can be used for the cleaning technology. Another field of application is surface wetting, the surface treatment or the change of the surface finish by powder coating or by particle collision with the surface. Typical methods therefor include blasting methods, such as shot peening. The fluidic component according to the invention can, however, also be used in fields of application dealing with fiber-containing fluids, such as in the paper industry.

(70) For all embodiments of the invention the following applies: The filter elements FE can serve to influence the spray characteristic of the exiting fluid stream (exit angle of the exiting fluid stream, oscillation frequency of the exiting fluid stream). The spacing of the filter elements in the individual inlet and/or outlet regions of the means for the targeted change in direction of the main flow may be the same, but also different. For example, the distance of the filter elements FE at the inlet 6a, 6b of a feedback channel FC can be smaller than the distance between the filter elements FE which are located at the outlet 8a, 8b of this feedback channel FC. The geometry of the fluidic components in principle can be designed freely. The invention is applicable to all fluidic components which include at least one feedback channel FC or a closed cavity.

REFERENCE NUMERALS

(71) 1 fluidic component 3 flow divider (splitter) 4 lateral wall of the flow chamber 6a, 6b inlet of feedback channel 8a, 8b outlet of feedback channel 10 main flow 11a, 11b block 15 fluid jet at outlet opening 20 secondary flow 30 recirculation area 105a, 105b separator 106 funnel-shaped attachment 107 outlet channel EX outlet opening FC feedback channel (secondary flow channel), means for the targeted change in direction of the main flow FE filter elements MC flow chamber PN inlet opening