PORTABLE PARTICLE COLLECTION DEVICE

Description

[0001] The present invention relates to a particle collecting device for collecting particles from surfaces of a test specimen for determining technical cleanliness according to the preamble of patent claim 1.

[0002] Particle collection devices according to the preamble of patent claim 1, marketed by the applicant, are already known from the generic prior art and are already successfully marketed for determining the technical cleanliness of test specimens, such as workpieces, circuit boards, and / or battery stacks. The known particle collection device comprises a suction line for manually or automatically scanning a surface of the test specimen to be tested. To filter the sucked-up particles from the suction air flow, the suction line opens tangentially into a centrifugal separator comprising a vertically oriented pipe section to form a vortex flow. For this purpose, the pipe section has an upper inlet region for redirecting the particle-laden suction air flow, which merges positively into a lower separation region of the pipe section.A collecting container for collecting the particles collected from the suction air flow is located beneath the downwardly open pipe section. Furthermore, a dip tube extends into the pipe section at the upper end, to which a vacuum supply line is connected at the outer end of the pipe section for connecting the suction air to a vacuum generation source.

[0003] During operation, the suction air volume flow laden with particles sucked up from the test surface of the test specimen flows as a particle / air volume flow into the pipe section of the centrifugal separator, with the suction air volume flow being deflected onto a circular path by the inner pipe section in the inlet area. This creates a vortex flow, and the rotation speed can be increased by the downwardly tapered cone. Due to the mass-dependent centrifugal force acting on the particles, this causes the particles in the suction air volume flow to be thrown against the inner pipe section, which leads to abrasion and chipping of the corners and edges of the particles. Because the particles are slowed down in this process, they trickle into the collection container located below and can thus be examined and evaluated for number, size and composition in a downstream optical analysis.However, the high mechanical stress acting on the particles in the suction air flow leads to a negative impact on the external properties of the particles, which results in a homogeneous surface. Chipping off the rough edges also has the disadvantage that an excessive proportion of small-grained particles is detected when determining technical cleanliness. Furthermore, practice has shown that even after the particles have been collected and transported to an analysis site, the particles are negatively impacted, leading to inaccurate values ​​when determining technical cleanliness.In addition to inadequate cleaning of the collection container before starting a new measurement series, another source of error is the poor quality of the transport container, which either leads to additional particles entering the designated transport container or a portion of the collected particles being lost during transport to an analysis site. Furthermore, the transport of the particles also leads to the surface of the particles being abraded by mutual rubbing and impact, thus negatively impacting the downstream optical analysis used to determine technical cleanliness.

[0004] Furthermore, the applicant's DE 2017 124 265 A1 is considered to be the prior art of the generic type. Furthermore, a particle collection device is known from GB 2 254 024 A. Furthermore, the publications US 2010 / 242 632 A1 and US 2005 / 274 170 A1 are also worthy of mention.

[0005] DE 10 2017 113 888 B3 discloses a centrifugal separator for separating at least two phases of a fluid, comprising a spiral-shaped base housing through which the fluid can flow, a separation chamber, and a separation tube. The centrifugal separator has an upper tangential inlet opening for the fluid at the base housing, a light fraction outlet opening, and a heavy fraction outlet opening at the lower end. The centrifugal separator tapers toward the lower end.

[0006] WO 2012 / 150672 A1 discloses a detection device for detecting biological particles, comprising a fan, collectors, a measuring device, and a control device. The collectors each have a cyclone shape. The control device introduces air into the detection device such that particles with diameters larger than the separation particle diameter are separated by the collectors. Subsequently, by applying a predetermined voltage to a discharge electrode, the separated particles are adsorbed onto a surface of the collector element. The measuring device measures the amount of particles originating from living organisms on the surface of the collector element.

[0007] JP H09155 239 A shows a miniaturized cyclone with a cyclone cylinder consisting of a straight tube and a separating section formed at its bottom. Particles flow into the cyclone cylinder tangentially into an upper section of the cylinder, where the turbulence and their own weight move the particles downwards to a separating plate. The particles are then swirled horizontally by the separating plate into another cylinder. A skirt is formed on the outer circumference of the separating plate to increase the separation efficiency.

[0008] Based on the aforementioned prior art, the object of the invention is to improve a generic particle collection device with regard to the quality and meaningfulness of the test results. The aim is to reduce the influence of disturbances that negatively influence and / or distort the measurement results of the particle collection device in order to achieve consistently high measurement quality in practice.

[0009] The object is achieved by the particle collection device having the features of patent claim 1. Advantageous developments of the invention are described in the subclaims.

[0010] In a manner advantageous according to the invention, the particle collection device according to the invention, which is particularly designed to be transportable and / or movable, comprises a centrifugal separator designed such that, when separating the particles from the particle / air volume flow, only a low mechanical load is applied to the particles, thereby preventing abrasion of the outer surfaces of the particles and chipping of the edges and corners of the particles. For this purpose, it was advantageously initially recognized according to the invention that, in order to determine the technical cleanliness of test specimens, such as workpieces, circuit boards, and / or battery stacks, particles with a particle size of less than 5.0 µm do not need to be collected and evaluated.Therefore, the centrifugal separator according to the invention for forming a vortex flow has a vertically oriented pipe section forming an upper inlet region and a lower separation region, wherein a suction line opens tangentially into the pipe section in the upper inlet region of the pipe section. Furthermore, the centrifugal separator comprises an immersion pipe that is oriented along the vertical or vertical extension of the pipe section and extends at least partially into the inlet region of the pipe section. It is operatively connected to a vacuum generation source via a vacuum supply line for generating the suction air volume flow.

[0011] During operation, as is common with particle collection devices of this type, the vacuum generation source generates a suction air flow. This allows the vacuum source to move over the surface of the test specimen (workpieces, circuit boards, and / or battery stacks) manually or using a fully automated handling device, and to suck up detachable particles from the surface to determine technical cleanliness. The particle / air flow flowing in the intake line flows into the inlet area of ​​the pipe section, where the particle-laden suction air flow is redirected by the inner pipe section to form a vortex flow.In this case, the rotating particle / air volume flow sinks into the separation region of the pipe section, which according to the invention is advantageously designed either as a hollow cylinder, in particular then integral with the inlet region as an empty pipe, or as a downwardly tapered cone such that the angle between the surface lines and the central axis of the cone (at an imaginary intersection point) is in a range between 0° and 8°, very particularly preferably between 0° and 4°, very particularly preferably 0°. In other words, it is preferably provided that the downwardly tapered cone is designed such that the intersection angle between a surface line of the cone and the central axis of the cone is less than or equal to, in particular less than, 8°, very particularly preferably 4°.

[0012] Alternatively, an embodiment is also conceivable which has a separation region of the pipe section which is designed as a downwardly widening cone. In this case, it is further provided that the angle between the surface lines and the central axis of the cone (at an imaginary intersection point) lies in a range between 0° and 15°, preferably between 0° and 11°, particularly preferably between 0° and 8°, very particularly preferably between 0° and 4°, wherein the imaginary intersection point is arranged above the cone. In other words, it is preferably provided that the downwardly widening cone is designed such that the intersection angle between a surface line of the cone and the central axis of the cone is less than or equal to, in particular less than, 15°, preferably 11°, particularly preferably 8°, very particularly preferably 4°.

[0013] This significantly reduces the mechanical stress acting on the particles as they continually impact and decelerate against the inner pipe section in the eddy current, as the slightly tapered cone in the separation area or the hollow cylinder formed in the separation area advantageously limits the speed of the generated eddy current. As a result, the particles are not only thrown against the inner pipe section for shorter periods, but also with less intensity, preventing abrasion of the particle surface. Furthermore, the proportion of small-grained particles is not increased by chipped-off particle fragments (corners and edges), which synergistically eliminates another interference factor in determining technical cleanliness.It is thus advantageously possible to gently filter out particles with a particle size greater than 5µm, preferably greater than 10µm, more preferably greater than 15µm from the particle / air volume flow, whereby this range is particularly relevant for determining technical cleanliness.

[0014] In a first development of the invention, it is advantageously provided that the collection container is designed as a replaceable disposable item. This advantageously makes it possible for the collection container to be used as a measurement sample for the temporary collection of particles by means of a centrifugal separator according to the invention, wherein after the corresponding test process, the collection container is replaced with another collection container. This makes it possible to evaluate the collection container using appropriate optical analysis means to determine technical cleanliness, decoupled from the operation of the particle collection device according to the invention. Furthermore, it can thus also be ensured that when a new test series is started, by inserting a new, previously unused collection container, no particles are already contained in the collection container before the start.By marking the corresponding collection container and the test specimens that have been cleaned with it - possibly only randomly or in sections - test specimens contaminated with an excessive number of particles can also be subsequently identified in order to carry out disposal or cleaning.

[0015] According to the invention, the collecting container has a horizontally oriented collecting surface for receiving the particles trickling out of the centrifugal separator during operation of the particle collecting device according to the invention, wherein a chemically acting adhesive is applied and / or provided on the collecting surface. The adhesive, designed as a chemically acting adhesive, can fix the particles trickling out of the centrifugal separator in their original (landing) position on the collecting surface. In this context, it is particularly advantageous to note that the uniform distribution of the particles on the collecting surface can be maintained, which is advantageous for the optical analysis of the particles in terms of number, size, and nature.Furthermore, securing the individual particles to the collection surface prevents the formation of particle clusters and clumps formed by multiple particles, thus improving the accuracy of the determination of technical cleanliness and eliminating the need for time-consuming and costly preparation processes for separating and distributing the particles. Furthermore, the adhesives prevent mutual abrasion of the edges and corners of the particles during transport of the collection container to an analysis site, particularly via an external postal service provider, which would also negatively influence the determination of technical cleanliness.

[0016] A further development of the particle collection device according to the invention comprises covering means for completely closing the collection container, which can be arranged in a form-fitting manner on the particle collection device when the collection container is in transport. This advantageously prevents contamination of the collected particles by additional particles coming from outside during transport, i.e., outside the measurement and / or testing time for determining technical cleanliness, which is determined by the measurement state in the particle collection device according to the invention.In this context, it is advantageously provided that the covering means are designed in such a way that they can be arranged in a form-fitting manner under the collecting container during the measuring time and / or test time, i.e. in the measuring state of the collecting container, wherein the form-fitting arrangement of the covering means on the collecting container during the measuring and / or test time prevents particles from adhering to the inner surfaces of the covering means, which would otherwise lead to additional contamination of the collecting container or in particular of the collecting surface when the collecting container is closed with the covering means.

[0017] In a further development, it is also provided that the collecting container has fixing means for fixing the covering means in the transport state and in particular also in the measuring state. Fixing means in the form of threads or locking means are particularly preferred. Alternatively, the fixing means can also be formed by an adhesive, wherein after the collecting container has been closed with the covering means, opening is possible by destroying the collecting container and / or the covering means, in particular at a predetermined breaking point and / or using a special tool. Alternatively, reopening is also advantageously possible by chemical or thermal treatment in order to detach the covering means from the collecting container again.This advantageously prevents the covering agents from detaching from the collection container during transport of the collection container to an analysis site and thus additional particles from entering the collection container, which would also have a negative impact on the measurement result.

[0018] Finally, within the scope of the invention, a further development of the particle collection device is also provided in which the collection container has a vertical extension of between 0.5 cm and 5 cm, preferably between 0.5 cm and 2.5 cm and / or a transverse and / or longitudinal extension and / or radial extension of between 2 cm and 15 cm, preferably between 4 cm and 10 cm. It has been found that such an extension and / or configuration of the collection container is particularly advantageous because, on the one hand, it provides a sufficiently large collection area for the particles collected in the context of technical cleanliness and, at the same time, is easy to handle in everyday life, i.e. in practice. This is also due to its suitability for sending the measurement sample to an analysis site via a postal service provider.

[0019] Furthermore, it is further provided that the collecting container and / or the covering means is / are made of a plastic material, in particular a transparent one. Advantageously, the transparent design of the collecting container enables testing and / or measuring personnel to carry out a quick visual inspection in order to roughly determine or estimate the degree of contamination or the condition of the collecting container, in particular the number of particles on the collecting surface, while particles are being sucked in by the particle collection device according to the invention. This advantageous design of the collecting container should preferably make it possible to view the number of particles on the collecting surface both in the measuring state and in the transport state.

[0020] In this context, it is also advantageous to provide the collection surface and / or the adhesive with a white or black contrast color for a visual inspection to determine and / or estimate the number of particles in the collection container and / or on the collection surface. This can improve the visual inspection and the optical analysis performed at the analysis site in the case of particles of different color, which can further improve the test result when determining technical cleanliness.

[0021] Finally, the invention also provides for the collecting container to form a hollow-cylindrical or conical outer surface comprising a base and / or tiered element. The inner surface of the base or tiered element forms the collecting surface for receiving the particles trickling out of the centrifugal separator, which surface, in particular, comprises the adhesive. This enables a cost-effective realization of a collecting container, particularly one designed as a disposable product. In a further development, the covering means can also be designed such that they can be arranged in a form-fitting manner on the top and bottom of the collecting container.

[0022] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

[0023] These show in: Fig. 1: a schematic side sectional view of a centrifugal separator according to the invention of a first preferred embodiment of the particle collecting device according to the invention, in Fig. 2: a schematic side sectional view of a centrifugal separator according to the invention of a second preferred embodiment of the particle collecting device according to the invention and in Fig. 3: an exploded view of a preferred embodiment of a collecting container for use in a particle collecting device according to the invention.

[0024] In the figures, elements and assemblies that are functionally identical or equivalent to one another are identified by the same reference symbols.

[0025] The Fig. 1shows a schematic side sectional view of a particle collection device 1 according to the invention for collecting particles from surfaces for particle analysis in the context of testing the technical cleanliness of test specimens, such as workpieces, circuit boards and / or battery stacks. To generate the suction air volume flow, the illustrated embodiment of the particle collection device 1 comprises a Fig. 1Graphically illustrated vacuum generation source, which is operatively connected to a centrifugal separator 2 of the particle collection device 1 according to the invention via a partially graphically illustrated vacuum supply line 11. For this purpose, a dip tube 10 protrudes at least partially into the centrifugal separator 2. In addition, the centrifugal separator 2 comprises a vertically arranged pipe section 3, which has an inlet region 4 and a separation region 5, wherein a suction line 6 opens tangentially into the inlet region 4 of the pipe section 3, the other end comprising a suction nozzle (not graphically illustrated) for moving away and sucking up the particles from the surface of the test specimen (workpiece, circuit board and / or battery stack).

[0026] Furthermore, a collecting container 9 is detachably arranged relative to a surrounding housing 8 of the particle collecting device 1 according to the invention. The collecting container 9 has a horizontally oriented collecting surface 16 for receiving particles trickling out of the centrifugal separator 2, on which chemically acting adhesives 17 are provided. Furthermore, the collecting container 9 comprises covering means 18 for completely closing the collecting container 9 in a transport state, said covering means being designed such that the covering means 18 can be arranged in a form-fitting manner beneath the collecting container 9 in the illustrated measuring state.

[0027] On the one hand, this enables the safe storage of the covering means 18 during operation of the particle collection device 1 and, on the other hand, the form-fitting arrangement of the covering means 18 prevents contamination of the inner surfaces of the covering means 18 with additional (dirt) particles, which would result in a negative influence or falsification of the test result (number, size and nature of the particles collected by the particle collection device 1 according to the invention).

[0028] During operation, a suction air volume flow is generated by means of the vacuum generation source (not shown graphically), which enables the suction of particles via the suction line 6. The particle / air volume flow flows tangentially into the vertically aligned pipe section 3 of the centrifugal separator 2, where it is deflected by the inner pipe section 7 such that a vortex flow forms in the centrifugal separator 2. Due to the centrifugal force acting on the particles, the particles are thrown against the inner pipe section 7 and thus decelerated, where they then trickle into the collecting container 9 provided below the pipe section 3. The tapered cone 13 in the separation area 5 of the pipe section 3 can further increase the rotation speed of the air volume flow, thereby increasing the centrifugal force and filtering even smaller particles from the air volume flow.However, according to the invention, the cone 13 is advantageously designed in such a way that excessively high speeds do not occur in the eddy current, since this would lead to a negative impairment in the analysis for determining the technical cleanliness due to the chipping off of corners and edges of the particles (mechanical stress).

[0029] Within the scope of the invention, it is intended in this context to limit the formation of the eddy current in such a way that it does not have a negative influence on the sucked-up particles. In this case, abrasion of corners and edges when filtering out the particles in the centrifugal separator 2 is to be avoided. This is advantageously made possible according to the invention in that the cone 13 forming the separation area 5 is designed in such a way that the angle α between the surface lines 14 of the cone 13 (in the separation area 5) and the central axis 15 of the cone 13 or in the Fig. 1shown variant of the central axis of the pipe section 3 has a value of only 9°.

[0030] Also in the Fig. 2 The structure of a further preferred embodiment of the particle collecting device 1 according to the invention is shown in a schematic side sectional view. In contrast to the Fig. 1 known embodiment, the variant now shown comprises a separation area 5 of the pipe section 3, which is designed as a hollow cylinder 12. In other words, the Fig. 2The angle α shown between the surface lines 14 of the hollow cylinder 12 (in the separation area 5) and the central axis 15 of the hollow cylinder 12 or the pipe section 3 is 0°, since these run parallel to each other and thus do not intersect. This design of the centrifugal separator 2, which is disadvantageous for filtering out small-grained particles, enables a particularly gentle filtering out of large particles from the particle / air volume flow, since the particles are not thrown against the inner pipe section 7 at a significantly higher speed when flowing through the separation area 5, as is the case with a conical design (approximately corresponding to the Fig. 1) would be the case. Nevertheless, such a design can be particularly advantageous with regard to an analysis of the technical cleanliness of coarse-grained particles, since the low speeds in the eddy current prevent the corners and edges of the particles from being knocked off, which is why the original nature of the particles, particularly with regard to the surface, is retained. In addition, the collecting container 9, which is designed as a disposable item made of a transparent plastic, is detachably arranged on the centrifugal separator 2 via a closure element 20 in order to position the collecting surface 16, which has the adhesive 17, relative to the centrifugal separator 2.

[0031] In the Fig. 3 is an exploded view of a preferred embodiment of the collecting container 9. The Fig. 3clarifies that the collecting container 9 has a vertical extension H of approximately 1 cm and is designed as a hollow cylinder with a base element provided for forming the collecting surface 16. Furthermore, the collecting container 9 can be completely closed in a transport state by means of covering means 18 composed of two parts in order to safely transport the collecting container with the particles contained therein to an analysis location. For this purpose, fixing means 19 designed as locking means are additionally provided, which are intended to prevent accidental opening of the covering means during transport. This advantageously prevents the particles filtered out of the suction air volume flow by means of the centrifugal separator 2 from being lost from the collecting container 9 during transport. Furthermore, the covering means 18 also ensure that no additional (dirt) particles enter the collecting container 9 during transport.Furthermore, the advantageous adhesives 17 allow the original position on the collecting surface 16 to be maintained as the particles trickle out of the centrifugal separator 16. In addition to completely preventing the formation of particle clumps and / or particle accumulations, which are detrimental to optical analysis of particle size, number, and composition, this also prevents the mutual knocking off of corners and edges of the filtered-out particles during a transport process, for example, to ship a full particle collection device to an analysis site via an external postal service provider.

[0032] As a result, the present invention enables the provision of a particle collecting device in a surprisingly simple manner which is particularly suitable for collecting particles from surfaces for determining technical cleanliness. Reference symbol

[0033] 1.Particle collection device 2.Centrifugal separator 3.Pipe section 4.Inlet area 5.Separation area 6.Suction line 7.Inner pipe section 8.Enclosure 9.Collecting container 10.Dip tube 11.Vacuum supply line 12.Hollow cylinder 13.Cone 14.Generation lines 15.Central axis 16.Collecting surface 17.Adhesive 18.Covering agent 19.Fixing agent 20.Closing element α:Angle R:Radial extension H:Vertical extension

Claims

1. A particle-collecting device (1) for collecting particles from surfaces for particle analysis in the context of testing the technical cleanliness of test bodies, in particular work pieces, conductor boards and / or battery stacks, with a casing (8) and a centrifugal force separator (2), which comprises a vertical pipe section (3) for forming a whirlpool, wherein the pipe section (3) comprises a suction pipe (6) in a entry area (4) which is intended for suctioning a particle-laden air mixture from a surface of a test body to be tested in such a manner that an aspirated particle / air volume flow rotates in the pipe section (3) in order to form a whirlpool and sinks into a separation area (5) of the pipe section (3), wherein the particles are centrifuged against the inner pipe section (7) and is thus separated from the air volume flow, the particle-collecting device (01) further comprising a collection container (9) detachably fixed to the centrifugal force separator (2) or the casing (8) in order to collect the separated particles in a measuring state of the collection container (9), and a submersion pipe (10), which is disposed on the centrifugal force separator (2) and to which a negative-pressure supply pipe (11) for generating the air volume flow for suctioning the particles is connected, wherein the separation area (5) is designed as a hollow cylinder (12) or a downwardly tapering or widening cone (13) in such a manner that the angle (α) between the generators (14) and the centric axis (15) of the hollow cylinder (12) or cone (13) at an imaginary point of intersection is in a range between 0° to 8°, most preferably between 0° and 4°, most preferably at 0°, characterized in that the collection container (9) forms a collection surface (16), which has chemically acting adhesion means (17) for fixing the deposited particles.

2. The particle-collecting device according to claim 1, characterized in that the collection container (9) is designed as an exchangeable disposable article.

3. The particle-collecting device according to claim 1 or 2, characterized in that the collection container (9) comprises covering means (18), wherein the covering means (18) is disposed in a form-fitting manner under the collection container (9) in the measuring state in such a manner that no particles are deposited and / or settled on the inner surface of the covering means (18), and wherein the covering means (18) is disposed on the collection container (9) in a transport state of the collection container (9) in such a manner that no additional particles are deposited and / or settled in the collection container (9), in particular on the collection surface (16).

4. The particle-collecting device according to claim 3, characterized in that the collection container (9) has fixation means (19) for fixing the covering means (18) on the collection container (9) in the transport state.

5. The particle-collecting device according to claim 1 to 4, characterized in that the collection container (9) has a height (H) between 0.5 cm to 5 cm, preferably between 0.5 cm to 2.5 cm and / or a width and / or length and / or radial extension (R) between 2 cm to 15 cm, preferably between 4 cm to 10 cm.

6. The particle-collecting device according to claim 1 to 5, characterized in that the collection container (9) is made of a plastic material, in particular of a plastomer material, and / or is transparent.

7. particle-collecting device according to claim 3 to 6, characterized in that the covering means (18) is made of a plastic material, in particular of a plastomer material, and / or is transparent.

8. The particle-collecting device according to claim 1 to 7, characterized in that the collection surface (16) and / or the adhesion means (17) have a white or black contrast coloration for an optical visual inspection to determine the number of particles.

9. The particle-collecting device according to claim 1 to 7, characterized in that the collection container (9) forms a hollow-cylindrical or conical jacket surface (21) comprising a bottom element and / or tier element (20), wherein the inner surface of the bottom element and / or tier element comprises the collection surface (16).