Cooling of an electrical device on a conveying channel

Abstract

The invention relates to an arrangement (200) of an electrical device (220) on a conveying channel (210) for conveying conveyed goods by means of a pneumatic conveying flow (211). The conveying channel (210) is delimited at least in part by a channel wall (290) made of a heat-conducting material. A component (240) of the electrical device (220), which component lies outside the conveying channel (210) and emits heat during operation, is thermally connected to an outer face (292) of the channel wall (290) in such a way that it can be cooled by dissipating (201) at least some of the lost heat emitted thereby by means of the pneumatic conveying flow (211). This makes simple and efficient cooling of the electrical device (220) possible.

Description

[0001] COOLING OF AN ELECTRICAL DEVICE ON A CONVEYOR CHANNEL

[0002] SPECIALIZATION

[0003] The present invention lies in the field of cooling electrical, heat-emitting devices. It relates to an arrangement of an electrical device on a conveying channel and to a method for cooling an electrical device on a conveying channel, according to the independent claims.

[0004] An exemplary application of the invention lies in the field of textile quality control in spinning preparation, wherein the electrical device is designed as a fiber cleaner for removing foreign substances from textile fibers, e.g. cotton fibers, pneumatically conveyed in the form of fiber flakes.

[0005] STATE OF THE ART

[0006] WO-2006 / 079426 A1 discloses a method and a device for removing foreign matter from fiber material, particularly raw cotton. An optical sensor system for detecting foreign matter and a removal device with at least one compressed air nozzle acting transversely to the fiber transport line are arranged one after the other in the transport direction along a pneumatic fiber transport line. Opposite the compressed air nozzle, the fiber transport line has a discharge opening for the foreign matter blown out by the removal device. Such devices in spinning preparation are called "fiber cleaners".

[0007] A common problem with such electrical devices is the heat generated by electrical or electronic components such as light sources, sensors, cameras, populated circuit boards, or motors. To prevent damage to the electrical device and ensure its proper functioning, the generated heat should be dissipated. The foreign object detection device according to WO-2017 / 076573 Al features a closed housing in which a lighting device is hermetically sealed. Furthermore, a liquid cooling unit is provided to dissipate the heat from the lighting device, allowing the heat generated during operation to be carried out of the housing by means of a liquid. The liquid cooling unit includes a heat exchanger through which heat is transferred from the liquid to the cooling air flowing through the heat exchanger.One disadvantage of this device is that a separate liquid circuit must be set up and maintained inside and outside the device for cooling.

[0008] The textile machine disclosed in US patent 2008 / 236178 comprises a device for cooling heat-generating electrical components, such as electrical switchgear and / or cabinets. An airflow passes through the textile machine and is then discharged to remove airborne particles, dust, and other contaminants from the interior. A portion of the supply air to the textile machine is directed against the heat-generating electrical components, absorbing their heat. A separate air duct must be provided within the textile machine for this portion of the airflow, for example, the interior of a double-walled switch cabinet door.

[0009] US Patent 4,699,208 A discloses a cooling device for removing heat from a compartment containing electronic or electrical components. It comprises a metallic finned body, attached to the outside of the compartment or formed as part of a circumferential wall of the compartment, and a fan located outside the compartment, which blows cooling air into the air channels of the finned body facing it. The longitudinal direction of the air channels of the finned body is inclined to the direction of flow of the cooling air before it is deflected by the finned body, such that no lint from the cooling air accumulates on the metallic finned body. The cooling device requires its own cooling air duct.

[0010] WO-2006 / 048303 Al deals with the cooling of heat-generating electronic components such as frequency converters in spinning machines. The components are equipped with cooling fins that project into an exhaust air stream, which extracts fly, dust, and other contaminants from the spinning area. This exhaust air stream is then filtered to remove these contaminants. Although the filter is positioned upstream of the cooling fins, it does not retain fine dust particles, necessitating occasional cleaning of the cooling fins.

[0011] Several cooling devices known from the prior art have the disadvantage that they require their own lines for the cooling medium – liquid or air. These take up additional space and lead to a more complex design and higher manufacturing costs for the electrical device being cooled. Several devices known from the prior art must also cope with the fouling of cooling fins, which can increase operating costs.

[0012] PRESENTATION OF THE INVENTION

[0013] It is an object of the invention to avoid or at least mitigate the disadvantages of the prior art. The invention aims to enable the cooling of an electrical device without complicating the design of the electrical device and / or the infrastructure it requires. The electrical device should not require any additional space for cooling. Its manufacturing and / or operating costs should not be increased by the cooling. The cooling process should be efficient and simpler than in the prior art. A further object of the invention is to provide a method for cooling an electrical device that avoids the disadvantages of the prior art and allows for efficient yet simple cooling of the electrical device.

[0014] These and other problems are solved by the device and the method according to the independent claims. Advantageous embodiments are specified in the dependent claims.

[0015] The invention is based on the idea of ​​arranging the electrical device to be cooled on an existing conveying channel for transporting a material with a pneumatic flow in such a way that the pneumatic flow acts as the cooling medium. This eliminates the need for separate lines for the cooling medium. To avoid impeding the unimpeded conveying of the material, no structural modifications are made to the interior of the conveying channel; in particular, no cooling fins protrude into the conveying channel.

[0016] The invention thus relates to an arrangement of an electrical device on a conveying channel for conveying a material with a pneumatic conveying flow. The conveying channel is at least partially bounded by a channel wall made of a thermally conductive material. A component of the electrical device located outside the conveying channel, which emits heat during operation, is thermally connected to an outer surface of the channel wall in such a way that it can be cooled by the pneumatic conveying flow through the dissipation of at least a portion of the waste heat it emits.

[0017] The canal wall can be made of a metal, for example steel.

[0018] In one embodiment, the component is thermally connected to the outside of the channel wall via at least one medium from the following quantity: metal, thermal paste, thermal pad.

[0019] The heat transfer coefficient between the component and the duct wall is, for example, greater than 100 W / (m²). 2 -K) and preferably greater than 500 W / (m²) 2 -K).

[0020] In one embodiment, the heat transfer coefficient between the component and the conveying channel is greater than 5 W / (m²). 2 -K) and preferably greater than 10 W / (m²) 2 -K).

[0021] In one embodiment, the component is one that emits a loss of heat of at least 5 W and preferably at least 20 W during operation.

[0022] The component is, for example, an element from the following set: light source, sensor, camera, populated circuit board, motor. In one embodiment, the inner side of the channel wall is smooth and unstructured, and preferably flat.

[0023] In one embodiment, the electrical device is designed to remove foreign substances from pneumatically conveyed textile fibers, e.g., cotton fibers. It can include a sensor for detecting the foreign substances, an evaluation unit connected to the sensor for evaluating signals from the sensor, and an elimination unit controlled by the evaluation unit for removing the foreign substances from the textile fibers. The sensor can include at least one camera and / or the elimination unit can include at least one compressed air nozzle for blowing the foreign substances out of the textile fibers.

[0024] The invention also includes a method for cooling an electrical device on a conveying channel for conveying a material with a pneumatic flow. The conveying channel is at least partially bounded by a channel wall made of a thermally conductive material. The material is conveyed in the channel by the pneumatic flow. A heat-emitting component of the electrical device located outside the conveying channel is thermally connected to an outer surface of the channel wall and is cooled by the pneumatic flow dissipating at least a portion of the waste heat it emits.

[0025] In one embodiment, foreign materials are removed from pneumatically conveyed textile fibers, e.g., cotton fibers, by the electrical device. The foreign materials can be detected by a sensor device of the electrical device and removed from the conveyed material by a removal device of the electrical device. The foreign materials can be detected by at least one camera of the sensor device and / or removed by at least one pneumatic nozzle of the removal device.

[0026] In this document, "thermally connected" means that good heat conduction should be possible between the thermally connected elements. For this purpose, the elements are either in direct contact with each other or connected via one or more media that allow good heat transfer, i.e., do not provide thermal insulation. Such media can be, for example, metals, thermal pastes, and / or thermal pads.

[0027] Due to the inventive arrangement of the electrical device to be cooled on an existing conveying channel, no separate lines for the cooling medium need to be provided, either inside or outside the electrical device. Consequently, additional effort and costs are eliminated in the manufacture and installation of the device. The cooling does not increase the space required for the electrical device.

[0028] No structural modifications are made to the interior of the conveying channel, in particular no cooling fins are installed. This ensures unimpeded conveying of the material. The problem of cooling fin contamination is eliminated, so their cleaning does not incur higher operating costs.

[0029] The invention enables efficient and simple cooling of the electrical device. It elegantly utilizes the pneumatic flow for cooling without diverting and diverting any part of the airflow.

[0030] LIST OF DRAWINGS

[0031] The following sections describe embodiments of the invention in detail with reference to the schematic drawings. The drawings and accompanying description refer to the example of a fiber cleaner in a spinning preparation plant. However, this example is not intended to limit the generality of the invention; the invention can also be used in other industries, such as the food industry, the tobacco industry, the pharmaceutical industry, the chemical industry, or the recycling industry.

[0032] Figure 1 schematically shows an embodiment of the arrangement according to the invention. Figure 2 shows a detail of an embodiment of an arrangement according to the invention (a) in a cross-section and (b) in a longitudinal section along line 11(b)- 11(b)-

[0033] For the sake of clarity and comprehensibility, the drawings are not to scale; this applies both to the relationships between the different elements and to the relationships between the different dimensions of each element.

[0034] IMPLEMENTATION OF THE INVENTION

[0035] Figure 1 shows an embodiment of the arrangement 100 according to the invention. The arrangement 100 according to this embodiment is a fiber cleaner for removing foreign substances from textile fibers, e.g. cotton fibers, in a spinning preparation plant. It includes a conveying channel 110 and an electrical device 120 attached to the conveying channel 110.

[0036] The textile fibers, in the form of fiber flakes 190, are conveyed through the conveying channel 110 by a pneumatic conveying flow 111. The pneumatic conveying flow 111 is indicated by arrows in the drawings. In the embodiment discussed here, the pneumatic conveying flow 111 always flows vertically from bottom to top. It could just as well flow from top to bottom, horizontally, or in any oblique direction determined by the conveying channel 110.

[0037] The conveying channel 110 is at least partially bounded by a channel wall 112 made of a thermally conductive material such as metal. It preferably has a rectangular cross-section, wherein the width of the rectangle (Fig. 1: horizontal direction) is much smaller than the depth of the rectangle (Fig. 1: direction perpendicular to the plane of the drawing). Exemplary dimensions are 7 cm for the width and 120 cm for the depth. In this embodiment, the inner surface of the channel wall 112 should be smooth and unstructured to prevent textile fibers from adhering to it and to ensure the unimpeded conveyance of the fiber flakes 190. Structures on the inner surface, such as cooling fins disclosed in the prior art, are avoided according to the present invention.

[0038] In this embodiment, the electrical device 120 is designed to remove foreign substances 191 from the textile fibers. For this purpose, it includes a sensor device 130 for detecting the foreign substances 191. The sensor device 130 includes, for example, at least one camera 131 that captures images of the fiber flakes 190 through a transparent window 113 in the wall 112 of the conveying channel 110. The area of ​​the conveying channel 110 in which the window 113 is located thus serves as a presentation chute 114 for the fiber flakes 190 and is designed accordingly.

[0039] On one side of the conveying channel 110, several cameras 131 can be mounted along the depth of the channel 110 to cover its entire depth. At least two cameras 131 can also capture images of the fiber flakes 190 from essentially opposite directions. The cameras 131 can, for example, have one- or two-dimensional CCD sensor arrays. The optical path from the presentation shaft 114 to each camera 131 can pass through at least one first deflecting mirror 132. Alternatively or additionally to optical foreign object detection, other measurement principles can be used in the sensor device 130, e.g., foreign object detection using ultrasound, microwaves, etc.

[0040] The sensor device 130 is connected to an evaluation device 140. The evaluation device 140 evaluates, on the one hand, the images taken by the at least one camera 131 of the sensor device 130 for foreign substances 191 that may be present in the fiber flakes 190. On the other hand, it controls a removal device 150 to remove the detected foreign substances 191 from the conveying channel 110 and the fiber flakes 190.

[0041] The discharge device 150 includes at least one compressed air nozzle, to which compressed air is supplied from a compressed air source (not shown) via a valve (not shown) that can be actuated by the evaluation device 140. A discharge air stream 151, indicated by an arrow, ejected from the compressed air nozzle, propagates essentially perpendicular to the conveying channel 110 and thus perpendicular to the pneumatic conveying flow 111. Along the depth of the conveying channel 110, several compressed air nozzles, e.g., 96, which can be actuated individually or in groups, can be arranged in the discharge device 150.

[0042] Opposite the discharge device 150, a discharge opening 115 is provided in a wall 112 of the conveying channel 110, into which a discharge channel 116 opens. The discharge airflow 151, expelled by at least one compressed air nozzle, flows through the discharge opening 115 from the conveying channel 110 into the discharge channel 116, carrying with it the detected foreign matter 191, which is thus discharged from the conveying channel 110 and the fiber flakes 190. The discharge opening 115 extends essentially over the entire depth of the conveying channel 110. Its length (in the direction of the pneumatic conveying flow 111) must be large enough to reliably receive the discharged foreign matter 191 and possibly a fiber flake 190 containing a foreign matter 191; it can, for example, be approximately 9 cm.

[0043] To illuminate the fiber flakes 190 in the presentation shaft 114, the electrical device 120 includes a lighting unit 160. In this example, the lighting unit 160 comprises four lighting modules 170, each containing at least one light source 171, e.g., at least one light-emitting diode (LED) or at least one fluorescent tube. The at least one light source 171 emits waste heat during operation, which must be dissipated for cooling.

[0044] According to the invention, the at least one light source 171 or a circuit board 172 on which the at least one light source 171 is mounted is thermally connected to an outer surface of the channel wall 112 in such a way that it can be cooled by the pneumatic conveying flow 111, which dissipates at least a portion of the waste heat it emits. The channel wall 112 absorbs the waste heat and transfers it to the pneumatic conveying flow 111. Details of an exemplary thermal connection are explained below with reference to Figure 2.

[0045] The lighting device 160 can further include second deflecting mirrors 161, which deflect the radiation 173 emitted by the at least one light source 171 towards the presentation slot 114. In this example, each lighting module 170 is assigned a second deflecting mirror 161. The second deflecting mirrors 161 are preferably cylindrical in order to collimate the radiation 173.

[0046] Like the lighting modules 170, other heat-emitting components of the electrical device 120 could also be thermally connected to an outside of the channel wall 112, e.g. the cameras 131 and / or the evaluation unit 140.

[0047] Figure 2 shows a detail of an embodiment of an arrangement 200 according to the invention of an electrical device 220 on a conveying channel 210. The two views show the arrangement 200 (a) in a cross section and (b) in a longitudinal section along line II(b)-II(b).

[0048] The conveying channel 210 is separated from the electrical device 220 by a channel wall 290 made of metal.

[0049] The electrical device 220 includes a lighting module 221 with at least one light source 230. In this example, the light sources 230 are configured as LEDs arranged in three rows 231-233 on a printed circuit board 240. The LEDs 230 in the different rows 231-233 can, for example, emit electromagnetic radiation in different wavelength ranges, i.e., ultraviolet radiation, visible light, and / or infrared radiation, whereby different LEDs 230 in one and the same row can be the same or different. Figure 2(b) shows 36 LEDs 230; however, the lighting module 221 can alternatively include fewer or more LEDs 230. The arrangement of the LEDs 230 on the printed circuit board 240 can be different from that shown in Figure 2.

[0050] The light sources 230 emit heat during operation. While an LED 230 is an efficient light source and emits only a few watts of heat, many LEDs 230, for example 96, can be mounted in a small space on the circuit board 240, and their heat losses can add up to a significant amount. Therefore, a circuit board 240 populated with such LEDs is considered a heat-emitting component within the meaning of this document. The total heat loss from a circuit board 240 populated with many LEDs 230 must be dissipated to prevent heat damage to electronic and other components of the electrical device 220.

[0051] For this purpose, the circuit board 240 is thermally connected to an outer surface 292 of the channel wall 290 in such a way that it is cooled by the pneumatic conveying flow 211 through the dissipation 201 of at least a portion of the waste heat it emits. The dissipation 201 of the waste heat is schematically indicated by thick arrows in Figure 2(a).

[0052] The circuit board 240 is positioned as close as possible to the outer surface 292 of the duct wall 290 and thermally connected to it. Ideally, it would be mounted directly on the outer surface 292 of the duct wall 290, but this is not always possible for various practical reasons.

[0053] The printed circuit board 240 is mounted in a printed circuit board housing 260 made of metal, e.g., aluminum. To dissipate the heat loss 201, the printed circuit board 240 is thermally connected to the printed circuit board housing 260 over a large area via a layer of thermal paste 250. The printed circuit board housing 260 is mounted on a support profile 280 made of metal, e.g., aluminum. To ensure good heat transfer between the printed circuit board housing 260 and the support profile 280, a large thermal pad 270 is clamped between the two components 260 and 280. The support profile 280 is attached to the outer surface 292 of the channel wall 290 made of metal, e.g., steel, and is in large-area contact with it. In the channel wall 290, the heat loss is distributed over a large area on an inner surface 291 of the channel wall 290, past which the pneumatic conveying flow 211 flows.The waste heat is transferred from the channel wall 290 to the pneumatic conveying flow 211 and from this away from the electrical device 220.

[0054] Metals are generally good thermal conductors, and the thermal connection in the lighting module 221, as shown in Figure 2, is further improved by the thermal paste 250 and the thermal pad 270. This ensures good heat transfer from the circuit board 240 to the pneumatic conveying flow 211. Radiation 234 emitted by the light sources 230 is indicated by arrows. In the direction of the emitted radiation 234, the lighting module 221 can be covered by a cover 235 that is essentially transparent to the emitted radiation 234. The cover 235 serves, on the one hand, to protect the circuit board 240 and the light sources 230 from contamination, and on the other hand, it can have a lens structure 236 for collimating the emitted radiation 234. It can be made, for example, of polymethyl methacrylate (PMMA).

[0055] The present invention is not limited to the embodiments discussed above. A person skilled in the art will be able to derive further variants that also fall within the scope of the present invention.

[0056] REFERENCE MARK LIST

[0057] 100 arrangement

[0058] 110 Conveyor channel

[0059] 111 pneumatic conveying flow

[0060] 112 Canal wall

[0061] 113 windows

[0062] 114 Presentation slot

[0063] 115 Excretory opening

[0064] 116 Excretory canal

[0065] 120 electrical devices

[0066] 130 sensor device

[0067] 131 Camera

[0068] 132 first deflecting mirror

[0069] 140 Evaluation unit

[0070] 150 Excretion facility

[0071] 151 Excretion airflow

[0072] 160 B lighting should be in the direction

[0073] 161 second deflecting mirror

[0074] 170 Lighting module

[0075] 171 Light source, LED

[0076] 172 printed circuit board

[0077] 173 emitted radiation

[0078] 190 Conveyed material, e.g. fiber flakes

[0079] 191 Foreign substance

[0080] 200 arrangement

[0081] 201 Dissipation of waste heat

[0082] 210 Conveyor channel

[0083] 211 pneumatic conveying flow

[0084] 220 electrical device

[0085] 221 Lighting module

[0086] 230 Light source, e.g. LED

[0087] 231-233 rows of LEDs

[0088] 234 Radiation

[0089] 235 Cover

[0090] 236 Lens structure 240 Circuit board

[0091] 250 thermal paste 260 circuit board enclosures

[0092] 270 heat-conducting pads

[0093] 280 carrier profile

[0094] 290 canal wall

[0095] 281 Inside of the channel wall

[0096] 282 Outside of the canal wall

Claims

PATENT CLAIMS 1. Arrangement (100, 200) of an electrical device (120, 220) on a conveying channel (110, 210) for conveying a conveyed material (190) with a pneumatic conveying flow (111, 211), wherein the conveying channel (110, 210) is at least partially bounded by a channel wall (112, 290) made of a thermally conductive material and a component (171, 172, 240) of the electrical device (120, 220) located outside the conveying channel (110, 210) that emits heat during operation is thermally connected to an outer surface (292) of the channel wall (112, 290) in such a way that it can be cooled by the pneumatic conveying flow (111, 211) by discharging (201) at least a part of the heat loss it emits.

2. Arrangement (100, 200) according to claim 1, wherein the channel wall is made of a metal, e.g. steel.

3. Arrangement (100, 200) according to one of the preceding claims, wherein the component (171, 172, 240) is thermally connected to the outer surface (292) of the channel wall (112) via at least one medium from the following quantity: metal (260, 280), thermal paste (250), thermal pad (270).

4. Arrangement (100, 200) according to one of the preceding claims, wherein the heat transfer coefficient between the component (171, 172, 240) and the channel wall (112, 290) is greater than 100 W / (m²). 2 -K) and preferably greater than 500 W / (m²) 2 -K) is.

5. Arrangement (100, 200) according to one of the preceding claims, wherein the heat transfer coefficient between the component (171, 172, 240) and the conveying channel (110, 210) is greater than 5 W / (m²). 2 -K) and preferably greater than 10 W / (m²) 2 -K) is.

6. Arrangement (100, 200) according to one of the preceding claims, wherein the component (171, 172, 240) is one that generates a heat loss of at least [value missing] during operation. emits 5 W and preferably at least 20 W.

7. Arrangement (100, 200) according to one of the preceding claims, wherein the component (171, 172, 240) is an element from the following set: light source (171, 230), sensor, camera, populated circuit board (172, 240), motor.

8. Arrangement (100, 200) according to one of the preceding claims, wherein an inner side (291) of the channel wall (112, 290) is smooth and unstructured and preferably flat.

9. Arrangement (100, 200) according to one of the preceding claims, wherein the electrical device (120, 220) is designed for removing foreign substances (191) from pneumatically conveyed textile fibers, e.g. cotton fibers.

10. Arrangement (100, 200) according to claim 9, wherein the electrical device (120, 220) includes a sensor device (130) for detecting the foreign substances (191), an evaluation device (140) connected to the sensor device (130) for evaluating signals from the sensor device (130) and a separation device (150) controlled by the evaluation device (140) for separating the foreign substances (191) from the textile fibers.

11. Arrangement (100, 200) according to claim 10, wherein the sensor device (130) includes at least one camera (131).

12. Arrangement (100, 200) according to claim 10 or 11, wherein the separation device (150) includes at least one compressed air nozzle for blowing the foreign substances (191) out of the textile fibers.

13. Method for cooling an electrical device (120, 220) on a conveying channel (110, 210) for conveying a conveyed material (190) with a pneumatic conveying flow (111, 211), wherein the conveying channel (110, 210) is at least partially bounded by a channel wall (112, 290) made of a heat-conducting material, the conveyed material (190) is conveyed in the conveying channel (111, 211) with the pneumatic conveying flow (111, 211), and a heat-emitting component (171, 172, 240) of the electrical device (120, 220) located outside the conveying channel (110, 210) is thermally connected to an outer surface (292) of the channel wall (112, 290) and is cooled by the pneumatic conveying flow (111, 211) through the removal (201) of at least part of the heat loss it emits.

14. Method according to claim 13, wherein foreign substances (191) are removed from pneumatically conveyed textile fibers, e.g. cotton fibers, by the electrical device (120, 220).

15. Method according to claim 14, wherein the foreign substances (191) are detected by a sensor device (130) of the electrical device (120, 220) and are removed from the conveyed material (190) by a separation device (150) of the electrical device (120, 220).

16. Method according to claim 15, wherein the foreign substances (191) are detected by at least one camera (131) of the sensor device (130) and / or are expelled by at least one pneumatic nozzle of the expulsion device (150).

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