Device for measuring the quantity of a powdered substance introduced into a carrier fluid line

Abstract

Device for capturing the quantity of a powdered substance (34) introduced into a carrier fluid line (14) by means of a metering device (5), comprising a metering device (5) with a storage container (6) for storing the powdered substance (34), with a conveying channel (11) opening into the carrier fluid line (14), and with means for conveying the powdered substance (34) in the conveying channel (11) from an outlet opening through which the powdered substance (34) enters the conveying channel (11) to its carrier fluid line-side outlet (20), characterized in that the carrier fluid line-side outlet section of the conveying channel (11) is designed as a compaction conveying section with a constriction (31) and with a compaction section upstream of this constriction in the conveying direction of the powdered substance (34), designed as an annular gap (33) that narrows towards the constriction (31). (30) is trainedsuch that the powdered substance (34) conveyed through the constriction (31) is compressed and therefore exits with internal cohesion of its particles, that at least one pressure sensor (37) for detecting the pressure prevailing in the carrier fluid line (14) is arranged upstream of the opening (20) of the conveying channel (11) into the carrier fluid line (14), and that an evaluation unit for evaluating the measurement signals detected by the pressure sensor (37) is assigned to the device.

Description

[0001] The invention relates to a device for capturing the quantity of a powdered substance introduced into a carrier fluid line by means of a metering device, comprising a metering device with a storage container for storing the powdered substance, with a conveying channel opening into the carrier fluid line and with means for conveying the powdered substance in the conveying channel from an outlet opening through which the powdered substance enters the conveying channel to its carrier fluid line-side outlet.

[0002] Such devices are used, for example, as part of vapor deposition systems, such as CVD plants. In such systems, it is preferred to dose the powdered precursor as a solid rather than as a liquefied powder. A challenge with such solid dosing is that only minute quantities need to be dosed, for example, amounts of 1 to 5 g / h or even less. EP 3 699 320 A1 discloses a dosing device for metering a powdered substance to supply a precursor to a CVD reactor. This previously known dosing device comprises a storage container for the powdered precursor. The storage container has a dispensing opening that leads into a conveying channel. A screw conveyor is arranged in the conveying channel to convey the powdered precursor contained therein.Its orientation is perpendicular to the discharge direction of the powdered substance from the storage container. The screw conveyor is driven by an electric motor. The drive can be continuous or intermittent. The conveying channel opens into the carrier fluid line. The amount of powdered precursor introduced into the carrier fluid line is measured by the drive of the screw conveyor. The powdered precursor particles, possibly loosely adhering to one another, are continuously introduced from the carrier fluid line opening of the conveying channel into the carrier fluid line by the screw conveyor's operation. In this known metering device, the opening into the carrier fluid line is designed like a Venturi nozzle, so that the carrier gas flowing past the opening draws in the powdered precursor particles.

[0003] This dosing device allows for the dosing of even minute quantities of solids. The dosing quantity depends on the feed rate of the screw conveyor and, due to the aforementioned Venturi effect, also on the flow velocity of the carrier gas in the carrier gas line. Experience with this previously known dosing device shows that minute quantities of solids are subject to a tolerance error of approximately ± 5%. While this is sufficient for many applications, increased requirements have led to numerous applications where the dosing of minute quantities of precursor solids, particularly in connection with the supply of powdered precursors in a vapor separation system, would be possible with tighter tolerances.

[0004] Based on this discussed state of the art, the invention aims to propose a solution to this problem.

[0005] According to the invention, this problem is solved by a generic device as mentioned above, in which the carrier fluid line-side outlet section of the conveying channel is designed as a compaction conveying section with a constriction and with a compression section upstream of this constriction in the conveying direction of the powdered substance, designed as an annular gap that tapers towards the constriction, so that the powdered substance conveyed through the constriction is compressed and therefore exits with internal cohesion of its particles, that at least one pressure sensor for detecting the pressure prevailing in the carrier fluid line is arranged upstream of the outlet of the conveying channel into the carrier fluid line, and that an evaluation unit for evaluating the measurement signals detected by the pressure sensor is assigned to the device.

[0006] In this device, dosing is carried out in principle according to the dosing device known from EP 3 699 320 A1. However, the device according to the invention has sensing means to detect the actual amount of substance introduced into the fluid, typically gas, flowing in the carrier gas line during operation of the device. This allows the formation of a control loop for controlling the conveying means with which the powdered substance is conveyed through the conveying channel. In the claimed sensing device, the conveying channel through which the powdered substance is conveyed is specially designed in its carrier fluid line-side opening section so that the solid particles are compressed from its opening into the carrier fluid line and thus exit with internal particle cohesion. In this way, the solid to be supplied is initially introduced into the carrier fluid line with the formation of a...The solid plug, adhering to the outlet of the conveying channel, is pressed into the carrier fluid line. This internal cohesion of the material particles, achieved through compaction, is sufficiently loose to allow the carrier fluid, typically carrier gas, flowing through the carrier fluid line, to detach agglomerates from the compacted material at a corresponding flow pressure or velocity. Typically, the detached agglomerates of the powdered material are fluidized within the carrier gas stream in the remaining flow path until they reach their application, for example, the reactor. To achieve solid plug formation, the end section of the conveying channel on the carrier fluid line side is designed as a compaction conveying section. This section has a constriction on the carrier fluid line side through which the powdered material is forced. A compression section is located upstream of this constriction in the conveying direction of the powdered material.The compaction section is characterized by a reduction in its free cross-sectional area towards the constriction and, furthermore, by the fact that it is formed by an annular gap that narrows towards the constriction. During operation, the conveying medium forces the powdered material through the compaction section and the constriction, with the conveyed material experiencing its greatest compaction in the area of ​​the constriction.

[0007] Upstream of the flow direction of a carrier fluid, such as a carrier gas, in the carrier fluid line, towards the outlet of the conveying channel, at least one pressure sensor is arranged, with which or with which the pressure prevailing in the carrier fluid line is or is measured. The at least one pressure sensor is connected to an evaluation unit, which is typically part of a control unit, in which the measured signals are evaluated. By injecting compacted powdered material into the carrier fluid line, forming a plug (compact) adhering in or at the outlet, the free cross-sectional area of ​​the carrier fluid line is reduced during operation of the device, thereby providing a corresponding back pressure to the carrier fluid flowing upstream of the plug. The larger the compacted material introduced into the carrier fluid line, the higher the back pressure generated.This pressure change can be detected by at least one pressure sensor arranged upstream of the pellet pressed into the carrier fluid line, in the direction of flow of the carrier fluid. The detectable pressure changes depend on the design of the system into which the device according to the invention is integrated. Typical pressure changes amount to 2–5 mbar. The plug formation can thus be observed via the increasing pressure in the carrier fluid line. If material or fragments (agglomerates) are eroded from the pellet as a result of the carrier fluid flowing past it, this manifests itself in a typically spontaneous pressure reduction in the carrier fluid line upstream of the conveying channel outlet. The breaking off or eroding of pellet agglomerates by the carrier fluid occurs discontinuously.This is based on the fact that, as the powdered material is forced through the constriction created by the opening into the carrier gas line, the inherent internal stresses within the carrier gas line dissipate with increasing distance from the constriction. This results in fragmentation or rupture of the plug in those areas where the internal stress has decreased sufficiently. The pressed particles broken off from the agglomerate are carried away with the carrier fluid. A cascade-like breaking off of agglomerates from such a pressed plug can also be observed. By appropriately reading the pressure sensor (continuously or intermittently), the processes of the pressed plug's formation through a pressure increase and its breakdown through the aforementioned breaking off of agglomerates as a pressure decrease can be detected.The degree of pressure build-up, as well as the measured pressure drop, is a measure of the actual amount of material introduced into the carrier fluid line and delivered to its application. This data is compared with the actual dosing rate required for the application. If there are deviations, the control of the conveying system is adjusted accordingly. In this way, the actual amount of solid material fed into a carrier fluid line is monitored directly. This allows for immediate responses during operation to, for example, fluctuations in drive speed or variations in the actual amount of solid material being fed into the conveying channel.

[0008] The pressure measurement described above, relative to the flow direction of the carrier fluid upstream of the conveying channel outlet, has the additional advantage that the measuring sensor – which is at least one pressure sensor – is not exposed to contamination by the introduced solid particles. Sensor calibrations, which are otherwise required at intervals for sensors with increasing contamination, are not necessary for the operation of this system.

[0009] Preferably, the annular gap in the compaction section is linearly tapered in the discharge section of the conveying channel on the carrier fluid line side. The tapering angle is preferably 60° to 120°, preferably 90° or approximately 90°. The length of the compaction section can be adjusted via the tapering angle. Depending on the powdered material being conveyed, the tapering angle will be selected to be larger or smaller. For many applications, a tapering angle of 90° or approximately 90° has proven particularly advantageous. In this case, the length of the compaction section is generally sufficient to ensure adequate pre-compaction of the conveyed solid particles up to the constriction, so that when the solid particles are forced through the constriction, the powdered material is compacted to the desired degree.Furthermore, a more uniform pressure build-up, reduced deposit formation on the inner wall of the annular gap, and an overall more consistent measurement signal can be expected. The degree of compaction is defined by the dimensioning of the clear width of the constriction. The constriction itself typically has a round, for example, circular, cross-sectional geometry. Since the surface of the solid pellet (plug) pressed into the carrier fluid line, which is exposed to the flow of the carrier fluid, is crucial for the described process, another embodiment provides for the constriction to have a cross-sectional geometry defined by a long axis and a short axis, with the short axis pointing in the direction of flow of the carrier fluid in the carrier fluid line. Such a cross-sectional geometry is preferably oval.It is understood that even with such a design of the constriction, the annular gap upstream in the conveying direction of the powdered material has a circular cross-sectional geometry.

[0010] The annular gap width is preferably constant along the entire length of the compaction section. Thus, any reduction in the cross-sectional area towards the constriction within the compaction section occurs solely due to the narrowing of the annular gap, not due to a reduction in the annular gap width. This prevents undesirable deposits from forming on the outer wall of the conveying channel, which narrows in this section.

[0011] The annular gap is bounded radially on the outside by a wall of the conveying channel. On the inside, in a preferred embodiment, the annular gap is formed by the end section of a screw conveyor serving as the conveying element, which points towards the opening of the conveying channel. In this configuration, the end section of the screw conveyor tapers towards the constriction.

[0012] In a further development of this device, it is provided that, in addition to the at least one first pressure sensor located upstream of the conveying channel opening in the carrier fluid line, at least one second pressure sensor is arranged downstream of the conveying channel opening. Preferably, the at least one second pressure sensor is arranged in a position where it is also protected from contamination. When the device is used as part of a vapor separation system, such as a CVD system, it is advantageous to arrange such a second pressure sensor in the reactor. With this configuration of the device, simultaneous differential pressure measurement between the two pressure sensors is possible. The changes in the differential pressure, as described above for the first pressure sensor located upstream of the conveying channel opening, are a measure of the amount of substance introduced into the carrier fluid line.If the device according to the invention is part of a vapor separation system and equipped with a pressure sensor upstream of the conveying channel outlet and another in the reactor, this measuring arrangement provides significant signal amplification, since the pressure in the reactor is regularly considerably lower than the pressure prevailing upstream of the conveying channel outlet due to the carrier gas flow. It is understood that the signal amplification is greater the larger the pressure difference between the pressure prevailing in the reactor and that in the carrier gas line. This signal amplification is achieved solely by the arrangement of the pressure sensors. Further signal amplification can be carried out in conjunction with signal evaluation. Pressures of 0.1 to 5 mbar can prevail in the reactor, while the pressure in the carrier gas line may be, for example, 10 mbar.Therefore, the pressure difference between the pressure in the reactor and in the carrier gas line can easily be two orders of magnitude. The measurement signal and the subsequent signal analysis are correspondingly good.

[0013] The invention is described below with reference to an exemplary embodiment and the accompanying figures. These show: Fig. 1: A schematic block diagram of a vapor separation device with a device according to the invention for detecting the quantity of a powdered substance (precursor) introduced into a carrier fluid line by means of a metering device, Fig. 2: An enlarged view of a section of the dosing device of the plant Fig. 1, Fig. 3a-3d: an enlargement of the outlet area of ​​the conveying channel into a carrier fluid line of the metering device of the Fig. 2 in a temporal sequence of a dosing operation, Fig. 4: a measurement signal curve to represent the pressure changes in the carrier fluid line upstream of the solids dosing system during continuous operation of the device and Fig. 5: one of the in Fig. 4 pressure measurement signal amplitudes shown in a larger temporal resolution.

[0014] A device 1 for vapor deposition of a substance on a substrate comprises a reactor 2, which in the illustrated embodiment is designed as a CVD reactor. Its interior is connected to a vacuum pump. The vacuum pump allows the pressure in the CVD reactor 2 to be reduced sufficiently to enable a chemical vapor deposition process. The vacuum pump (not shown in the figure) is connected to a pump line 3 opening into the interior of the CVD reactor 2. The CVD reactor 2 can be opened to allow a substrate to be coated by the CVD process to be placed on and removed from a support 4. A metering device, designated by reference numeral 5, serves to supply a precursor for depositing, for example, a metallic layer onto a substrate placed on the support 4.The metering device 5 has a reservoir 6, which in the illustrated embodiment is cylindrical. The reservoir 6 is sealed at the top by a closure element 7. The upright reservoir 6 has a conically tapered outlet 8 at its bottom. The reservoir 6 is mounted on a conveying block 9, which has a funnel-shaped opening on its side facing the reservoir 6, continuing the tapered shape of the outlet 8. The design of the conveying block 9 with its individual parts is described in more detail below with reference to the illustration of the figure. Fig. 2 described. The tapered end of the conical outlet-extending taper 10 of the conveying block 9 opens into a conveying channel 11 running transversely to the outlet direction from the storage container 6, with an integrated screw conveyor 12. The screw conveyor 12 is driven rotaryally by a stepper motor 13. The conveying channel 11 opens into a carrier gas line 14. The screw conveyor 12 serves to feed powdered material stored in the storage container 6 as a precursor for the layer to be deposited into a carrier gas stream flowing through the carrier gas line 14 when the device 1 is in operation. The direction of flow of the carrier gas stream is towards the CVD reactor 2. The carrier gas line 14 supplies an evaporator 15. The precursor supplied with the carrier gas stream evaporates at the evaporator 15.The metal released during the evaporation process of a metallic coating is then deposited on the surface of the substrate located on the support 4. During operation, the CVD reactor 2 typically operates at a pressure of only 2 to 5 mbar. The carrier gas line 14 is connected to a carrier gas reservoir or supply (not shown in the figure), from which the carrier gas is drawn according to the diagram. Fig. The gas flows into the carrier gas line 14 in the direction indicated by arrow 1. A branch 16 of the carrier gas line 14 leads directly into the CVD reactor 2 and into a gas shower head 17.

[0015] In an alternative configuration, the carrier gas line 14 and the gas shower head 17 are each connected to their own independent carrier gas supply.

[0016] A special feature of the metering device 5 is that the interior of the storage container 6 is also in fluid communication with the carrier gas line 14. For this purpose, a vent line 18 is provided, through which the interior of the storage container 6 is connected to the carrier gas line 14. In the figure, a filter is located in the region of the opening 19 of the vent line 18, which is permeable to the carrier gas but not to the powdered substance stored in the storage container 6. A switching valve 22 is installed in the carrier gas line 14 between the opening 20 of the conveying channel 11 into the carrier gas line 14 and the opening 21 of the vent line 18 into the carrier gas line 14. In the illustrated embodiment, the switching valve 22 is a solenoid valve. This is connected to a control unit, also not shown in detail.

[0017] A helical mixing tool 23 is arranged in the storage container 6. In the illustrated embodiment, this tool is constructed in two parts. A first tool section is located in the cylindrical part of the storage container 6. A second helical section is located in the area of ​​the outlet 8 and extends into the conical taper 10, which forms part of the outlet of the conveying block 9. The drive shaft 24 of the mixing tool 23 passes through the closure body 7 in a sealed manner and is connected to an electric motor 25. The electric motor 25, which in the illustrated embodiment is also a stepper motor, is attached to the closure body 7.Since the closure body 7 must be removed from and reinstalled on the reservoir 6 for opening and refilling, a coupling piece 26 is part of the drive shaft 24. This coupling piece is torque-locked onto the upper section of the drive shaft 24 of the mixing tool 23. The coupling piece 26 can be pulled off the drive shaft together with the closure body 7. The coupling piece 26 extends through the closure body 7 and seals it.

[0018] Fig. Figure 2 shows the conveying block 9 in an enlarged and therefore more detailed view. A conveying channel pipe 27 is inserted into the conveying block 9 to form the conveying channel 11. The auger 12 is located in this pipe, with the outer diameter of the auger 12 being slightly smaller than the inner diameter of the conveying channel pipe 27 and thus of the conveying channel 11. Thread-like inner wall structures are incorporated into the inner wall of the conveying channel pipe 27, which serve as a trap for the powdered material conveyed through the conveying channel 11. This causes the powdered material to form a coating on the inner wall of the conveying channel pipe 27. The conveying channel pipe 27 has an opening 28 on its side facing the outlet constriction 10 of the conveying block 9, through which the powdered material in the storage container 6 can enter the conveying channel 12.Opposite this opening 28, a cleaning pinion 29 is rotatably mounted in the conveying block 9. Its teeth mesh with the helix of the screw conveyor 12. When the screw conveyor 12 is driven, the cleaning pinion 29 rotates with it. Due to the teeth of the cleaning pinion 29 engaging in the spaces between the helix, any compacted powdery material contained therein is removed. A material trap is connected to the interior space in which the cleaning pinion 29 is located (not shown) to collect the material forced out of the spaces between the helix.

[0019] Fig. Figure 3a shows an enlarged view of the end section of the conveying channel 11 facing the carrier gas pipeline 14, including the screw conveyor 12 located therein. The end section of the conveying channel 11 facing the carrier gas pipeline is designed as a compaction conveying section and has a compaction section 30 that transitions into a constriction 31 towards the outlet 20. The conveying channel 11, which has a circular cross-section, retains this cross-sectional geometry up to the constriction 31, which also has a circular cross-sectional geometry in the illustrated embodiment. The free cross-sectional area decreases linearly in the compaction section 30 towards the constriction 31 in the illustrated embodiment. The screw conveyor's end section 32, which is free of the screw conveyor, engages in the compaction section 30.The end section 32 of the screw conveyor 12 tapers towards the opening 20 with the same tapering angle as the conveying channel 11. Thus, within the compaction section 30, an annular gap 33 with a constant gap width is provided, tapering towards the constriction 31. The tapering angle in the compaction section 30 is approximately 90°.

[0020] During operation of the metering device 5, powdered substance 34 located in the conveying channel 11 is conveyed by the screw conveyor 12 towards the outlet 20. In the compaction section 30, this substance is successively compacted towards the constriction 31 by the previously described narrowing until the powdered substance (precursor) experiences its greatest compaction as it is forced through the constriction 31. As a result of this compaction, the compacted powdered substance 34, with its particles holding together internally, is forced out of the constriction 31, so that a plug 35 forms within the carrier gas line 14 as a compact, as described in Fig. 3 in its initial formation. This adheres to the compressed material still located within the constriction 31. Initially, the internal cohesion of the particles of the powdered substance 34 in the plug 35 is so high that the carrier gas flowing in the carrier gas line 14 does not pick up any solid particles or agglomerates thereof, or at most only a negligible amount as suspended load. Through the successive squeezing out of the constriction 31 of the powdered substance 34, the plug 35 enlarges (see Fig. 3b). Plug formation is also supported by the tendency of the compacted powdered substance 34 to expand again within the carrier gas line 14. Only when the plug 35 is of sufficient size and thus the flow pressure from the carrier gas is sufficiently high, are fragments (agglomerates) broken out of the plug 35 (see Fig. 3c). Typically, following the initial breaking out of a plug fragment, further plug fragments are eroded due to the weakening caused by the broken-out fragment. The breaking out of agglomerates then occurs in a cascade-like manner. The erosion process of plug fragments from the plug 35 ends when the internal stresses of the compacted powdered material 34 are still so high, or the internal cohesion of the particles of the powdered material 34 is still so strong in the remaining residual plug, that agglomerates cannot be separated under the prevailing conditions. (see Fig. 3d).

[0021] To determine the actual quantity of precursor introduced into the carrier gas line 14, the CVD system 1 has a detection device 36 provided for this purpose. In the illustrated embodiment, this detection device 36 is designed as a pressure measuring device and has a first pressure sensor 37 and a second pressure sensor 38. The first pressure sensor 37 is located upstream of the opening 20 of the metering device 5 in the carrier gas line 14, in the direction of the carrier gas flow. In Figures 3a to 3d, only the pressure sensor 37 is shown. The pressure sensor 37 is arranged a short distance from the opening 20 of the conveying channel 11, in the direction of the carrier gas flow, and is designed to detect the pressure prevailing in the carrier gas line 14. The second pressure sensor 38 extends with its measuring tip into the CVD reactor 2.

[0022] The first pressure sensor 37 records the pressure prevailing in the carrier gas line 14 over time during operation of the system 1. Due to the Fig. As described in sections 3a to 3d, the plug formation associated with solid dosing is caused by the increasing size of the plug 35 and the resulting reduction in the cross-sectional area of ​​the carrier gas line 14 in the direction of flow of the carrier gas upstream of the plug 35 – where the first pressure sensor 37 is located – due to the accumulating back pressure. The pressure building up in the carrier gas line 14 at the position of the pressure sensor 37 as a result of plug formation can thus be detected in the measurement signal of the pressure sensor 37. As soon as the plug 35, formed from compacted precursor particles, begins to erode, the pressure drops due to the breaking away of agglomerates. The pressure build-up and pressure drop depend on the reduction (during plug formation) and the increase (during plug breakdown) of the cross-sectional area of ​​the carrier gas line 14.This, in turn, taking into account the mechanical expansion after passing through the constriction 31, depends on the volume of the plug 35, so that the amount of solid introduced into the carrier gas can be determined very precisely from the way the measurement signal changes during plug formation and / or dissolution. Depending on the design of the metering operation, it is not necessary to determine the exact amount of solid introduced from the pressure difference. Rather, in many cases it is sufficient to monitor the consistency of the operation of the metering device 5 with regard to the dispensing of precursor material in this way. If, for example, plug formation occurs too slowly, the delivery rate into the carrier gas line 14 is too low. If plug formation occurs too quickly, too much solid is introduced into the carrier gas line 14.

[0023] The measurement signals from the pressure sensor 37 are evaluated in an evaluation unit, which, in the illustrated embodiment, is part of a control unit not shown in detail in the figures. The control unit itself is the one that controls the stepper motor 13, so that the stepper motor can be activated immediately upon detection of irregularities. The measures described significantly reduce the dosing tolerance to ± 0.2% to 1%.

[0024] Similarly, pressure monitoring can be carried out using the second pressure sensor 38, namely as the differential pressure between the section in the carrier gas line 14, in which the pressure sensor 37 is located, and the pressure prevailing in the reactor 2.

[0025] Fig. Figure 4 shows the signal recorded by pressure sensor 37 over time (t). The pressure variations at pressure sensor 37 in the carrier gas line 14 are clearly visible. Up to each maximum, a plug 35 forms at the opening 20 of the conveying channel 11. This plug then erodes in the descending branch of each amplitude as described above, followed by the formation of the next plug, recognizable by the ascending branch of the next amplitude. This measurement curve shows the discontinuous release of the precursor material into the carrier gas stream. Since the temporal sequence is small relative to the flow velocity of the carrier gas stream, and since the agglomerates detached in the plug 35 are fluidized immediately during and after erosion, also due to the particles' tendency to further expand, the desired coating in reactor 2 nevertheless occurs continuously.Such a solid dosing system can also be used to apply a large number of extremely thin layers successively to a substrate located on the support 4.

[0026] Fig. 5 shows one of the in Fig.The amplitudes shown in Figure 4 are presented at a higher temporal resolution. The steeper pressure rise during plug formation at the opening 20, up to the point of maximum pressure, is clearly visible. Once the erosion process of the plug 35 by the flowing carrier gas stream has begun, this plug 35 is gradually broken down, but, as the shallower slope of this measurement signal edge shows, less rapidly than its formation. In the descending measurement signal branch, it can be observed repeatedly that the continuous supply of powdered substance 34 through the constriction 31 also results in the intermittent formation of a new plug, but not to the extent that the plug 35 regenerates to its original size.

[0027] The evaluation of the measurement signal then allows the aforementioned conclusions to be drawn.

[0028] The invention has been described with reference to exemplary embodiments. Without departing from the scope of protection described by the applicable claims, numerous further embodiments of the inventive concept would be apparent to a person skilled in the art, without these needing to be explained in more detail within the scope of these explanations. Reference symbol list 1 CVD system 2 CVD reactor 3 Pump line 4 carriers 5 Dosing device 6 storage containers 7 locking bodies 8 outlet 9 Conveyor block 10 Rejuvenation 11 Conveyor channel 12 screw conveyors 13 stepper motor 14 Carrier gas pipeline 15 evaporators 16 branch of the carrier gas pipeline 17 Gas shower head 18 Ventilation duct 19 Mouth 20 Mouth 21 Mouth 22 Switching valve 23 Mixing tool 24 Drive shaft 25 Electric motor drive 26 coupling piece 27 Conveyor pipe 28 Opening 29 cleaning gears 30 Compaction section 31 Narrow point 32 Final section 33 Annular gap 34 Powdered substance (precursor) 35 grafts 36 Recording device 37 Pressure sensor 38 Pressure sensor 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 3 699 320 A1 [0002, 0006]

Claims

[1] Device for capturing the quantity of a powdered substance (34) introduced into a carrier fluid line (14) by means of a metering device (5), comprising a metering device (5) with a storage container (6) for storing the powdered substance (34), with a conveying channel (11) opening into the carrier fluid line (14) and with means for conveying the powdered substance (34) in the conveying channel (11) from an outlet opening through which the powdered substance (34) enters the conveying channel (11) to its carrier fluid line-side outlet (20), characterized by, that the carrier fluid line-side outlet section of the conveying channel (11) is designed as a compaction conveying section with a constriction (31) and with a compression section (30) upstream of this in the conveying direction of the powdered substance (34), designed as a tapered annular gap (33) towards the constriction (31), so that the powdered substance (34) conveyed through the constriction (31) is compressed and therefore exits with internal cohesion of its particles, that at least one pressure sensor (37) for detecting the pressure prevailing in the carrier fluid line (14) is arranged upstream of the outlet (20) of the conveying channel (11) into the carrier fluid line (14), and that an evaluation unit for evaluating the measurement signals detected by the pressure sensor (37) is assigned to the device. [2] Device according to claim 1, characterized by , that the narrowing of the annular gap (33) in the compression section (30) is linear. [3] Device according to claim 1 or 2, characterized by , that the width of the annular gap (33) is constant over the extent of the compression section (30). [4] Device according to claim 2 or 3, characterized by , that the tapering angle of the annular gap (33) is between 60° and 120°, in particular 90° or about 90°. [5] Device according to any one of claims 1 to 4, characterized by , that a rotary-driven screw conveyor (12) arranged in the conveying channel (11) is provided as a conveying means, the end section (32) of which carrier fluid line side engages in the compression section (30) and this end section (32) forms the inner radial boundary for the annular gap (33) located in the compression section (30). [6] Device according to any one of claims 1 to 5, characterized by that the evaluation unit is part of a control unit through which the funding is controlled with regard to its delivery rate. [7] Device according to any one of claims 1 to 6, characterized by , that during operation of the facility the carrier fluid line (14) is permeated with gas. [8] Device according to any one of claims 1 to 7, characterized by , that the device is part of a vapor separation plant (1) comprising a reactor (2) with at least one evaporator (15) for evaporating the powdered substance, from which evaporation products the coating layer is deposited on the substrate, with a vacuum pump connection for connecting a vacuum pump to generate the negative pressure required for the separation in the reactor (2) and with a substrate carrier (4) as well as a carrier gas line (14) connected to the evaporator (15) and supplied by a carrier gas supply. [9] Device according to claim 8, characterized by, that the device has at least one additional pressure sensor (38) connected to the evaluation unit, through which the pressure in the reactor (2) can be detected. [10] Device according to any one of claims 1 to 9, characterized by that the evaluation unit is set up to provide a differential pressure result from two pressure measurements. [11] Device according to claim 10, characterized by , that the evaluation unit is set up to provide a differential pressure result from successive pressure measurement signals. [12] Device according to claim 10 with reference to claim 9, characterized by that the evaluation unit is set up to provide a differential pressure result from two simultaneously performed pressure measurements.

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