Sorting device

Abstract

Sorting device for sorting objects (6) by means of air bursts (2), with at least one sorting nozzle (3) having a nozzle channel (9) surrounded by a channel wall (13), which opens with an air outlet opening (4) at a nozzle front (12) of the sorting nozzle (3) and which has an air inlet section (16) spaced apart in a channel longitudinal direction (14a) from the air outlet opening (4), which can be selectively connected to or disconnected from a compressed air source (P) by means of a sorting valve (18) in order to either generate an air outlet flow (23) exiting the air outlet opening (4) with an air burst (2) blowing away a passing object (6) or to interrupt such an air outlet flow (23), characterized in thatthat the nozzle channel (9) has a local cross-sectional narrowing (28) in an acceleration channel section (27) extending between the air inlet section (16) and the air outlet opening (4), which causes an increase in the flow velocity of the air outlet flow (23), wherein in the region of the acceleration channel section (27) a venting channel system (30) communicating with the atmosphere, which causes venting of the nozzle channel (9) when the air outlet flow (23) is interrupted, opens into the nozzle channel (9) with at least one venting opening (33) separate from the air outlet opening (4).

Description

[0001] The invention relates to a sorting device for sorting objects by means of air bursts, with at least one sorting nozzle, which has a nozzle channel surrounded by a channel wall, which opens with an air outlet opening at a nozzle front of the sorting nozzle and which has an air inlet section spaced apart in a channel longitudinal direction from the air outlet opening, which can be selectively connected to or disconnected from a compressed air source by means of a sorting valve in order to either generate an air outlet flow exiting the air outlet opening with an air burst blowing away a passing object or to interrupt such an air outlet flow.

[0002] A sorting device of this type, known from EP 2 923 777 B1, is used in sorting systems to selectively remove individual objects from a conveyed stream by means of a pneumatic compressed air blast, taking certain criteria into account. The fields of application are diverse and range from the food industry and recycling applications to the manufacture of electronic chips. The individual air blasts can be generated by means of a 2 / 2-way valve, which can be designated as a sorting valve. This valve can selectively connect or disconnect an air inlet section of a nozzle channel extending within a sorting nozzle to a compressed air source. When connected to a compressed air source, the nozzle channel is subjected to an air outlet flow, which exits as an air blast at an air outlet opening.When the compressed air source is disconnected, the airflow is interrupted. However, some time elapses until the pressure in the nozzle channel has decreased sufficiently to prevent compressed air from being expelled and affecting the passing objects. This is compensated for by maintaining a relatively large distance between the passing objects, which, however, reduces sorting efficiency. Furthermore, especially with very small objects, such as rice, peas, or similar foodstuffs, it is very difficult to maintain sufficiently large distances due to the sheer number of objects. As a result, a blast of air can unintentionally blow away objects that should not be sorted.

[0003] The invention is based on the objective of taking measures that enable a high sorting frequency with reliable sorting behavior when sorting objects using air pulses.

[0004] To solve this problem, a sorting device of the type mentioned above is provided in such a way that the nozzle channel in an acceleration channel section extending between the air inlet section and the air outlet opening has a local cross-sectional narrowing that causes an increase in the flow velocity of the air outlet flow, wherein in the area of ​​the acceleration channel section a venting channel system communicating with the atmosphere, which causes venting of the nozzle channel when the air outlet flow is interrupted, with at least one venting opening separate from the air outlet opening, opens into the nozzle channel.

[0005] The sorting device according to the invention can be used to sort out objects that are moved past the air outlet of a nozzle channel of a sorting nozzle in a stream of objects consisting of a multitude of objects arranged in series. The stream of objects generally moves vertically due to gravity, with the air outlet of the sorting nozzle facing horizontally towards the moving stream of objects. As soon as an object to be sorted out has been identified based on certain sorting criteria, a sorting valve, which until then interrupts the air outlet flow, can be switched to generate an air outlet flow through the nozzle channel. This air outlet is released in a pulsed burst at the air outlet, blowing the object moving past it out of the stream and thereby sorting it out.As soon as the airflow through the sorting valve is interrupted, a pressure drop occurs in the nozzle channel, not only through the air outlet opening, but also, according to the invention, through a venting channel system with at least one vent opening that opens into the nozzle channel. The large venting cross-section provided by the additional venting channel system can cause a virtually instantaneous pressure drop in the nozzle channel, so that the airflow at the air outlet opening is stopped very quickly and no relevant blown air acts on the passing stream of objects. This makes it possible to guide the objects to be sorted past the air outlet opening with very little distance between them. Objects following an object being sorted are not blown away despite the small distance between them. This enables a very high sorting frequency with high sorting quality.To ensure that the intensity of the air blast is not impaired by the vent opening communicating with the atmosphere, the nozzle channel features a local cross-sectional constriction in the area of ​​the at least one air outlet opening. This constriction causes a local increase in the flow velocity of the exiting air stream, resulting in a reduction of the static pressure in the relevant section of the nozzle channel, designated as the acceleration channel section. Consequently, during the exiting air stream, no, or at least no significant, amount of compressed air is expelled through the venting channel system; instead, ambient air is even drawn in. Therefore, during a compressed air stream used to generate an air blast, no, or at least no significant, leakage from the nozzle channel can occur. Accordingly, the sorting device, in conjunction with the advantages described above, is characterized by high energy efficiency.

[0006] Advantageous further developments of the invention are set out in the dependent claims.

[0007] Preferably, the at least one vent opening in the nozzle channel is oriented such that it does not point towards the air inlet section of the nozzle channel, i.e., it is not oriented against the direction of the air outlet flow. This effectively prevents the compressed air forming the air outlet flow from entering the vent channel system directly and causing even a minor leakage. An imaginary normal vector of the opening plane of each vent opening has no directional components that point towards the air inlet section in the longitudinal direction of the nozzle channel.

[0008] Preferably, the at least one vent opening of the venting duct system is oriented such that it faces exclusively towards the air outlet opening of the nozzle duct. Assuming that a cross-section of the vent opening, referred to as the opening cross-section, extends in a plane referred to as the opening plane, the vent opening is particularly oriented such that the normal vector of the opening plane extends parallel to the longitudinal direction of the duct and points towards the air outlet opening.

[0009] In a similarly advantageous embodiment of the sorting device, the at least one vent opening of the venting duct system is oriented such that it faces the air outlet opening both in the longitudinal direction of the nozzle duct and transversely to an opposite wall section of the duct. In this case, the normal vector of an opening plane of the vent opening can be inclined with respect to the longitudinal direction of the nozzle duct, in particular with a directional component pointing towards the air outlet opening and a directional component radial to the longitudinal direction of the duct.

[0010] In a simple embodiment of the sorting device, the venting channel system opens into the nozzle channel with exactly one vent opening. Preferably, the single vent opening is located on a radially central longitudinal axis of the nozzle channel extending along its length. However, the single vent opening can also be arranged off-center, and in particular at a radial distance from the central longitudinal axis of the channel.

[0011] A particularly effective design of the sorting device features a venting channel system that opens into the nozzle channel via several vent openings distributed along its circumference. The circumferential direction of the nozzle channel is understood to be a direction around a central longitudinal axis of the nozzle channel. Although it is theoretically possible for the multiple vent openings to be offset from one another along the longitudinal direction of the channel, it has proven advantageous for all of them to lie in a common radial plane orthogonal to the longitudinal axis of the nozzle channel. This is especially true for the center of the cross-sectional area of ​​each individual vent opening.

[0012] Preferably, if several vent openings are present, all vent openings are arranged at a radial distance from the center of the channel, i.e., from a central longitudinal axis of the nozzle channel.

[0013] If the sorting device is equipped with multiple vent openings, the venting channel system preferably comprises several venting channels, each of which opens into the nozzle channel via one of the multiple vent openings. In a different embodiment, at least one venting channel of the venting channel system with multiple vent openings can open into the nozzle channel.

[0014] The local cross-sectional narrowing of the nozzle channel can be achieved, for example, by means of a concentric constriction of the channel wall. However, an embodiment is considered particularly advantageous in which the local cross-sectional narrowing is caused by at least one flow obstruction projecting into the nozzle channel from the channel wall as an individual wall projection, which the air outlet flow can flow around. The air outlet flow can pass this flow obstruction, in particular, laterally, i.e., on its two sides oriented in the circumferential direction of the nozzle channel.

[0015] Preferably, the at least one flow obstruction projects radially from the channel wall into the nozzle channel, ending freely within the nozzle channel at a radial distance from the channel wall.

[0016] To create the cross-sectional constriction, a single flow obstruction can be arranged in the nozzle channel. Alternatively, the local cross-sectional constriction can also be formed by several flow obstructions projecting into the nozzle channel and distributed along its circumference. In this case, there is a particularly uniform distribution along the circumference of the nozzle channel.

[0017] At least one vent opening is advantageously formed in a flow obstruction of the aforementioned type, with the venting channel system extending at least partially within the flow obstruction in question. If several vent openings are present, each vent opening is advantageously formed in a flow obstruction traversed by the venting channel system. If several flow obstructions are present, each flow obstruction advantageously has a vent opening. However, a hybrid configuration with several flow obstructions is also possible, of which only one or more, but not all, flow obstructions have a vent opening.

[0018] It is considered particularly advantageous if at least one flow obstruction is formed by a pipe section projecting from the channel wall into the nozzle channel, which is penetrated longitudinally by a pipe channel forming the vent channel of the vent channel system and which terminates at an inner pipe end face located in the nozzle channel with a vent opening. The pipe section can be formed as a single piece or separately from the channel wall.

[0019] In one possible embodiment, the pipe section is L-shaped, comprising an outer pipe leg extending radially from the channel wall towards the center of the nozzle channel and an inner pipe leg projecting from the outer pipe leg towards the air outlet opening and terminating with an inner pipe end face that surrounds the vent opening. In such a design, the vent opening is advantageously oriented exclusively towards the air outlet opening of the nozzle channel.

[0020] In another advantageous design, a pipe section acting as a flow obstruction projects radially in a straight line from the channel wall into the nozzle channel, its inner end face enclosing the vent opening lying in a plane inclined relative to the longitudinal direction of the nozzle channel. In this case, the vent opening is expediently oriented both towards the air outlet opening in the longitudinal direction of the nozzle channel and, transversely, towards an opposite section of the channel wall.

[0021] The sorting device is expediently equipped with a sorting valve connected to the air inlet section of the nozzle channel, which can be optionally connected to or disconnected from a compressed air source. The sorting valve is, in particular, a 2 / 2-way valve. The sorting valve is electrically actuated, and the sorting device is, in particular, equipped with an electronic control unit for electrical valve actuation. The electronic control unit can actuate the sorting valve, in particular, depending on the result of an inspection of objects based on specific sorting criteria.

[0022] The sorting device can be equipped with a single sorting nozzle or with multiple sorting nozzles. If the sorting device contains multiple sorting nozzles, it is advantageous for each sorting nozzle to have its own sorting valve. Multiple sorting nozzles can be arranged side by side, particularly in a nozzle row, such that their air outlet openings are aligned in a straight line with a gap between them.

[0023] The invention will now be explained in more detail with reference to the accompanying drawing. This drawing shows: Fig. 1 a preferred first embodiment of the sorting device according to the invention, wherein a sorting nozzle of the sorting device is shown in a longitudinal section according to section plane II. Fig. 2 is shown, Fig. 2 a cross-section of the sorting nozzle Fig. 1 according to section plane II-II in Fig. 1, Fig. 3 a further embodiment of the sorting device according to the invention, wherein a sorting nozzle of the sorting device is shown in a longitudinal section according to section plane III-III. Fig. 4 is shown, and Fig. 4 a cross-section of the sorting nozzle according to section plane IV-IV in Fig. 3.

[0024] The drawing illustrates two advantageous embodiments of a sorting device 1, which is designed to emit air pulses 2, indicated by arrows, at an air outlet opening 4 of a sorting nozzle 3 at time intervals.

[0025] The air bursts 2 are impulsive air currents directed at a stream of objects 5 passing in front of the sorting nozzle 3 during the operation of the sorting device 1. This stream consists of a multitude of individual objects 6 that move past the air outlet 4 in a successive row in an object movement direction 7 indicated by an arrow. Typically, the object movement direction 7 is vertically downwards, meaning that the objects 6 fall downwards past the horizontally oriented air outlet 4, which is located laterally next to the object stream 5.

[0026] With the aid of the sorting device 1, the objects 6 can be separated into good and defective parts. In particular, when using the sorting device 1, defective parts contained in the object stream 5 are blown away by bursts of air 2. This is used, for example, in the food industry for the quality sorting of granular foods such as rice or coffee. Another example application is the sorting out of defective computer chips during chip manufacturing in the electronics sector. In all these cases, before passing through the air outlet opening 4, the object stream 5 passes through a test station (not shown in the drawing) that is coupled to an electronic control unit 8, preferably integrated as part of the sorting device 1, to generate an object-specific burst of air 2 based on predefined sorting criteria.

[0027] The sorting device 1 can have only a single sorting nozzle 3 or several sorting nozzles 3. In particular, several sorting nozzles 3 are arranged side by side in such a way that parallel object sorting from several adjacent object streams 5 is possible.

[0028] The sorting nozzle 3 can, in principle, have any spatial orientation. A horizontal orientation, as shown in the exemplary embodiment where the air outlet opening 4 is horizontally oriented, is advantageous.

[0029] The sorting nozzle 3 defines a nozzle channel 9, which is peripherally enclosed, i.e., on its radial outer circumference, by a channel wall 13. The nozzle channel 9 has a longitudinal channel axis 14, indicated by a dashed line, which defines the channel center and whose axial direction is designated as the longitudinal channel direction 14a. A direction around the longitudinal channel axis 14 is designated as the circumferential direction 15 of the nozzle channel 9 and is indicated by a double arrow. The channel wall 13 extends around the nozzle channel 9 in the circumferential direction 15.

[0030] As an example, the sorting nozzle 3 is designed in a tubular shape. The channel wall 13 is also tubular in shape. However, other shapes are also possible for the sorting nozzle 3.

[0031] The nozzle channel 9 preferably has a round, and in particular circular, cross-section. This applies to the exemplary embodiment.

[0032] The sorting nozzle 3 has a nozzle front 12 oriented horizontally sideways in the illustrated embodiments, at which the nozzle channel 9 opens with the air outlet opening 4. Preferably, the air outlet opening 4 has a circular cross-section.

[0033] In the longitudinal direction 14a of the channel, at a distance from the air outlet opening 4, the nozzle channel 9 has a channel section designated as the air inlet section 16, which, at least in the operational state of the sorting device 1, is fluidically connected to a valve outlet 17 of a sorting valve 18, preferably also belonging to the sorting device 1. For example, the sorting nozzle 3 has a connection element in the region of the air inlet section 16, which can be connected to, or is connected to, the valve outlet 17 via a fluid line. Preferably, however, the sorting nozzle 3 is formed as part of, for example, a block-shaped valve carrier, on which the sorting valve 18 is mounted such that its valve outlet 17 communicates directly with a channel opening of the nozzle channel 9 connected to the air inlet section 16.

[0034] The sorting valve 18 has a valve inlet 19 which, during operation of the sorting device 1, is connected to a compressed air source P via a feed channel 22. The feed channel 22 can be at least partially formed by a compressed air line, for example, a compressed air hose.

[0035] The sorting valve 18 can alternately assume one of at least two possible switching positions. One of these switching positions, illustrated in the drawing, is a shut-off position in which the valve inlet 19 is separated from the valve outlet 17. In this case, no compressed air from the compressed air source P can flow into the air inlet section 16 of the nozzle channel 9.

[0036] Another switching position of the sorting valve 18 is an open position, in which the valve inlet 19 is fluidically connected to the valve outlet 17. In this case, compressed air from the compressed air source P can flow through the sorting valve 18 into the air inlet section 16 to generate a compressed air flow, indicated by several arrows and referred to below as the air outlet flow 23, axially through the nozzle channel 9. Since the sorting valve 18 is only ever switched to the open position briefly, as intended, the air outlet flow 23 exits as an air pulse 2 at the air outlet opening 4.

[0037] Normally, the sorting valve 18 assumes a rest position representing the closed position. Switching to the open position and the subsequent return to the closed position is controlled by the electronic control unit 8, which is electrically connected to an electrical actuator 24 of the sorting valve 18. The sorting valve 18 is typically actuated by directing an outgoing air blast 2 onto an object 6 to be sorted, which at the same moment assumes a sorting position 25 upstream of the air outlet opening 4 (indicated by dashed lines in the drawing). The object is then blown out of the object stream 5 according to arrow 26.

[0038] The sorting valve 18 is in particular a 2 / 2-way valve having only the two aforementioned switching positions.

[0039] The sorting valve 18 is specifically designed as a so-called quick-switching valve, which can be switched from the closed position to the open position and back again in a very short time. It is specifically a monostable directional control valve. The air pulse 2 should be short enough so that objects following the object 6 being sorted in the object stream 5 are not also blown away.

[0040] The sorting valve 18 is preferably a solenoid valve or a piezo valve.

[0041] Special features of the sorting device 1 ensure a particularly rapid pressure reduction in the nozzle channel 9 after the air outlet flow 23 is interrupted, for example, after the sorting valve 18 is switched to the shut-off position. This rapid pressure reduction results in an almost immediate cessation of airflow at the air outlet 4, so that objects following the object 6 being sorted are not also blown away in an inaccurate manner, even if the distance between the objects is relatively small. The special pressure reduction measures consist of providing the nozzle channel 9 with an additional venting option, independent of the air outlet 4, when the sorting valve 18 is switched to the shut-off position. This additional venting does not require a separate venting valve and is therefore highly effective, virtually wear-free, and very cost-effective.

[0042] The measures described above provide for a local cross-sectional constriction 28 in the longitudinal direction 14a of the nozzle channel 9, located in a channel section 27 extending between the air inlet section 16 and the air outlet opening 4. This section is referred to as the acceleration channel section 27 for clarity. This constriction increases the flow velocity of the air outlet flow 23. As the compressed air passes through the cross-sectional constriction 28, it must flow through a smaller cross-sectional area compared to the air inlet section 16, resulting in an acceleration of the airflow. In a forward channel section 29 of the nozzle channel 9, extending between the acceleration channel section 27 and the air outlet opening 4, the airflow can be decelerated again to the flow velocity prevailing in the air inlet section 16.The nozzle channel 9 is designed in particular such that it has a larger cross-sectional area in the air inlet section 16 and in the front channel section 29 than in the area of ​​the acceleration channel section 27.

[0043] The special measures for accelerated venting include a venting duct system 30, which opens into the nozzle duct 9 in the area of ​​the acceleration duct section 27 via at least one venting opening 33. The venting opening 33 is provided in addition to the air outlet opening 4, which also vents the nozzle duct 9 when the air outlet flow 23 is interrupted. The at least one venting opening 33 communicates continuously with the atmosphere via the venting duct system 30. For example, the venting duct system 30 opens into the atmosphere surrounding the sorting nozzle 3 via at least one outlet opening 34, spaced apart from the at least one venting opening 33 in the longitudinal direction 14a of the duct.

[0044] With an air outlet flow 23, the accelerated airflow in the area of ​​the cross-sectional constriction 28 causes a reduction in the static internal pressure according to Bernoulli's principle. This static internal pressure is lower than the atmospheric pressure at the at least one outlet opening 34, so that, as indicated by arrow 35, ambient air is drawn into the nozzle channel 9 through the venting duct system 30. This suction effect prevents unwanted air leakage of the flowing compressed air through the venting duct system 30 when an air outlet flow 23 is present.

[0045] However, as soon as the air outlet flow 23 is interrupted, the suction effect ceases, and the overpressure still present at that time in the nozzle channel 9, and in particular in the front channel section 29, causes the air in the nozzle channel 9 to flow out to the atmosphere through the venting channel system 30 according to the dashed vent arrows 36. The air in the nozzle channel 9 enters the venting channel system 30 via the at least one vent opening 33 and exits it, for example, through the at least one outlet opening 34.

[0046] In this way, if the air outlet flow 24 is interrupted, a very rapid pressure relief in the nozzle channel 9 occurs automatically without additional control measures.

[0047] Overall, the measures described enable additional ventilation of the nozzle channel 9 by means of at least one additional vent opening 33 when the air outlet flow 23 is interrupted, whereby the measure of cross-sectional narrowing 28 ensures that no leakage occurs through the vent opening 33 when the air outlet flow 23 is present.

[0048] In both illustrated embodiments, the local cross-sectional constriction 28 is caused by at least one flow obstruction 37, which projects from the channel wall 13 into the nozzle channel 9 in the manner of a wall projection, transversely to the longitudinal direction 14a of the channel. The channel cross-section remaining between the at least one flow obstruction 37 and the channel wall 13 forms the cross-sectional constriction 28, through which the compressed air can flow past the at least one flow obstruction 37.

[0049] In the exemplary embodiment of the Fig. 1 and Fig. 2. The local cross-sectional narrowing 28 is caused by a single flow obstruction 37. In contrast, in the embodiment of the Fig. 3 and Fig. 4 The local cross-sectional constriction 28 consists of several individual flow obstructions 37, which are arranged distributed in the nozzle channel 9 in the circumferential direction 15. Preferably, the distribution is regular. By way of example, four flow obstructions 37 are present.

[0050] When the term "flow obstruction 37" is used below, it refers to each flow obstruction 37 present in the individual case, unless otherwise stated.

[0051] In principle, the venting channel system 30 can be designed independently of the flow obstructions 37, wherein the at least one venting opening 33 is not part of a flow obstruction 37, but is formed independently in the channel wall 13. However, the measure implemented in both illustrated embodiments is considered more advantageous, according to which the venting channel system 30 passes through at least one and preferably every flow obstruction 37, and each venting opening 33 is formed in a flow obstruction 37.

[0052] In the exemplary embodiment of the Fig. 1 and Fig. 2 is formed as a single vent opening 33 in the single flow obstruction 37, whereas in the embodiment of the Fig. 3 and Fig. 4 each of the several flow obstructions 37 is provided with its own vent opening 33 and is accordingly also penetrated by the vent channel system 30.

[0053] Both illustrated embodiments share a preferred design in which the flow obstruction 37 is formed by a pipe section 38 that projects transversely from the channel wall 13 into the nozzle channel 9, perpendicular to the longitudinal direction 14a of the channel. The pipe section 38 is penetrated in its longitudinal direction by a pipe channel 41, which forms a vent channel 42 of the vent channel system 30.

[0054] Each pipe section 38 terminates at its end region opposite the channel wall 13 with an inner pipe end face 43, at which the vent channel 42 opens with the vent opening 33.

[0055] In the exemplary embodiment of the Fig. 1 and Fig. 2 The ventilation duct system 30 is formed by a single ventilation duct 42. In the exemplary embodiment of the Fig. 3 and Fig. 4 The venting duct system 30 contains the multiple venting channels 42 formed in all pipe sections 38, wherein the venting duct system 30 opens into the nozzle channel 9 with multiple venting openings 33. These multiple venting openings 33 are arranged distributed in the circumferential direction 15 in the nozzle channel 9, which is particularly evident from Fig. 4 can be seen. Fig. Figure 3 illustrates a preferred embodiment in which the multiple vent openings 33 are located in a common radial plane 45 which is orthogonal to the longitudinal axis 14 of the channel.

[0056] It is also advantageous if all of the multiple vent openings 33 are arranged at a radial distance from the channel center of the nozzle channel 9, which is defined by the longitudinal channel axis 14. This applies to the embodiment of the Fig. 3 and Fig. 4 to.

[0057] In all illustrated embodiments, the vent channels 42 open at an end region of the respective pipe section 38 opposite the inner pipe end face 43, with an outlet opening 34. Preferably, the outlet openings 34 are located throughout in the region of the radial outer circumference 44 of the channel wall 13. All illustrated embodiments have in common that the flow obstruction 37 projects from the channel wall 13 in a radial direction with respect to the longitudinal axis 14 of the channel into the nozzle channel 9 and terminates freely within the nozzle channel 9 at a radial distance from the radially opposite wall section of the channel wall 13.

[0058] According to Fig. 1 and Fig. 2. It is advantageous if the pipe section 38 is L-shaped and, in particular, bent. It has an outer pipe leg 46, which extends radially into the nozzle channel 9 from the channel wall 13 with respect to the longitudinal axis 14 of the channel. An inner pipe leg 47 adjoins the end region of the outer pipe leg 46 facing away from the channel wall 13 – for example, with an arcuately curved section – and projects in the longitudinal direction 14a of the channel towards the air outlet opening 4 and terminates with the inner pipe end face 43 surrounding the vent opening 33.

[0059] In this way, the vent opening 33 faces exclusively towards the air outlet opening 4. With respect to a plane designated as the opening plane 48, in which the opening cross-section of the vent opening 33 extends, the vent opening 33 is oriented such that the normal vector 49 of the opening plane 48 is parallel to the longitudinal direction 14 of the channel and points towards the air outlet opening 4. Thus, the vent channel system 30 opens into the nozzle channel 9 with exactly one vent opening 33. It is advantageous in this context if the single vent opening lies on the central longitudinal axis 14 of the nozzle channel 9. Preferably, the central longitudinal axis 14 of the channel intersects the center of the opening cross-section of the vent opening 33. However, a radial offset between the center of the opening cross-section and the longitudinal axis 14 of the channel would also be feasible.

[0060] In the exemplary embodiment of the Fig. 3 and Fig. 4. The pipe sections 38, each forming one of the flow obstructions 37, project straight radially from the channel wall 13 into the nozzle channel 9. Preferably, both the outlet openings 34 and the vent openings 33 lie in the radial plane 45. Preferably, the radial plane 45 intersects the cross-sectional center of each of the aforementioned outlet openings 34 and vent openings 33.

[0061] The inner pipe end face 43 surrounding each vent opening 33 is, in the exemplary embodiment of the Fig. 3 and Fig. 4 is oriented such that it lies in a plane inclined with respect to the longitudinal direction 14a of the channel. This inclined plane corresponds to an opening plane 48 in which the opening cross-section of the associated vent opening 33 extends. The inclination is chosen such that the normal vector 49 of each opening plane 48 is inclined with respect to the longitudinal direction 14a of the channel, so that it has, in particular, both a directional component pointing towards the air outlet opening 4 in the longitudinal direction 14a of the channel and a directional component radial with respect to the longitudinal axis 14 of the channel.

[0062] In both embodiments, the aforementioned design achieves the measure that each vent opening 33 is oriented such that it does not face the air inlet section 16 in the longitudinal direction 14a of the nozzle channel 3 9. The normal vector 49, which is orthogonal to the opening plane 48, in no case has a directional component that points towards the air inlet section 16 in the longitudinal direction 14a of the channel.

[0063] The variants of flow obstructions 37 implemented in the illustrated embodiments can also be combined with one another in the same sorting nozzle 3. Furthermore, it is possible to combine the multiple flow obstructions 37 of the embodiment of the Fig. 3 and Fig. 4 corresponding to the flow obstruction 37 of the Fig. 1 and Fig. 2 to design or a single flow obstruction 37 deviating from the embodiment of the Fig. 1 and Fig. 2 according to the design of the Fig. 3 and Fig. 4 to design. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2923777 B1

[0002]

Claims

[1] Sorting device for sorting objects (6) by means of air bursts (2), with at least one sorting nozzle (3) having a nozzle channel (9) surrounded by a channel wall (13), which opens with an air outlet opening (4) at a nozzle front (12) of the sorting nozzle (3) and which has an air inlet section (16) spaced apart in a channel longitudinal direction (14a) from the air outlet opening (4), which can be selectively connected to or disconnected from a compressed air source (P) by means of a sorting valve (18) in order to either generate an air outlet flow (23) exiting at the air outlet opening (4) with an air burst (2) blowing away a passing object (6) or to interrupt such an air outlet flow (23), characterized by, that the nozzle channel (9) in an acceleration channel section (27) extending between the air inlet section (16) and the air outlet opening (4) has a local cross-sectional narrowing (28) which causes an increase in the flow velocity of the air outlet flow (23), wherein in the area of ​​the acceleration channel section (27) a venting channel system (30) communicating with the atmosphere, which causes venting of the nozzle channel (9) when the air outlet flow (23) is interrupted, with at least one venting opening (33) separate from the air outlet opening (4) opens into the nozzle channel (9). [2] Sorting device according to claim 1, characterized by , that the at least one vent opening (33) of the vent duct system (30) is oriented such that it is not directed towards the air inlet section (16) of the nozzle duct (9) in the longitudinal direction (14a) of the duct (14a) of the nozzle duct (9). [3] Sorting device according to claim 1 or 2, characterized by , that the at least one vent opening (33) of the venting duct system (30) is directed exclusively towards the air outlet opening (4) of the nozzle duct (9), wherein an opening cross-section of the vent opening (33) expediently extends in an opening plane (48) whose normal vector runs parallel to the duct longitudinal direction (14a) of the nozzle duct (9) and points towards the air outlet opening (4). [4] Sorting device according to any one of claims 1 to 3, characterized by, that the at least one vent opening (33) of the venting duct system (30) is directed both in the longitudinal direction (14a) of the nozzle duct (9) towards the air outlet opening (4) and transversely thereto towards an opposite wall section of the duct wall (13), wherein an opening cross-section of the vent opening (33) expediently extends in an opening plane (48) whose normal vector is inclined with respect to the longitudinal direction (14a) of the nozzle duct (9) and in particular has a directional component pointing towards the air outlet opening (4) as well as a directional component radial with respect to the longitudinal direction (14a) of the duct. [5] Sorting device according to any one of claims 1 to 4, characterized by , that the venting duct system (30) opens into the nozzle duct (9) with exactly one vent opening (33). [6] Sorting device according to claim 5, characterized by, that the only vent opening (33) is placed on a radially central longitudinal axis (14) of the nozzle channel (9) extending in the longitudinal direction (14a) of the channel. [7] Sorting device according to any one of claims 1 to 4, characterized by , that the venting channel system (30) opens into the nozzle channel (9) with several venting openings (33) distributed along the circumference of the nozzle channel (9), wherein the several venting openings (33) are advantageously located in a common radial plane (45) orthogonal to a longitudinal axis (14) of the nozzle channel (9) extending in the longitudinal direction (14a). [8] Sorting device according to claim 7, characterized by , that all of the multiple vent openings (33) are arranged at a radial distance from the channel center of the nozzle channel (9). [9] Sorting device according to claim 7 or 8, characterized by, that the venting duct system (30) has several venting ducts (42) which each open into the nozzle duct (9) via one of the several venting openings (33). [10] Sorting device according to any one of claims 1 to 9, characterized by , that the local cross-sectional narrowing (28) of the nozzle channel (9) is caused by at least one flow obstruction (37) projecting into the nozzle channel (9) as an individual wall projection from the channel wall (13) and which can be circumvented by the air outlet flow (23). [11] Sorting device according to claim 10, characterized by , that at least one flow obstruction (37) extends radially from the channel wall (13) into the nozzle channel (9) and terminates freely within the nozzle channel (9) at a radial distance from the channel wall (13). [12] Sorting device according to claim 10 or 11, characterized by, that the local cross-sectional narrowing (28) of the nozzle channel (9) is caused by a single flow obstruction (37) projecting into the nozzle channel (9) as an individual wall projection from the channel wall (13) and which can be circumvented by the air outlet flow (23). [13] Sorting device according to claim 10 or 11, characterized by , that the local cross-sectional narrowing (28) is caused by several flow obstacles (37) projecting into the nozzle channel (9), each of which can be flowed around by the air outlet flow (23), and which are distributed in the circumferential direction (15) of the nozzle channel (9). [14] Sorting device according to any one of claims 10 to 13, characterized by , that at least one and preferably every vent opening (33) is formed in a flow obstruction (37) penetrated by the venting duct system (30). [15] Sorting device according to claim 14, characterized by, that if there are several flow obstructions (37) a vent opening (33) is formed in each flow obstruction (37). [16] Sorting device according to any one of claims 10 to 15, characterized by , that at least one flow obstruction (37) is formed by a pipe section (38) extending from the channel wall (13) into the nozzle channel (9), which is penetrated in its longitudinal direction by a pipe channel (41) forming the vent channel (42) of the vent channel system (30), which opens at an inner pipe end face (43) located in the nozzle channel (9) with a vent opening (33). [17] Sorting device according to claim 16, characterized by, that at least one pipe section (38) is L-shaped, having an outer pipe leg (46) extending radially from the channel wall (13) towards the center of the nozzle channel (9) and an inner pipe leg (47) extending from the outer pipe leg (46) towards the air outlet opening (4) and ending with an inner pipe end face (43) enclosing the vent opening (33). [18] Sorting device according to claim 16 or 17, characterized by , that at least one pipe section (38) extends radially in a straight line from the channel wall (13) into the nozzle channel (9), its inner pipe end face (43) enclosing the vent opening (33) lies in a plane inclined with respect to the longitudinal direction (14a) of the nozzle channel (9). [19] Sorting device according to any one of claims 1 to 18, characterized by, that it has a sorting valve (18) connected to the air inlet section (16) of the nozzle channel (9), which can be actuated by means of an electronic control device (8), which can be optionally connected to or disconnected from a compressed air source (P) and which is expediently designed as a 2 / 2-way valve.

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