Coating system for coating a substrate and process for coating a substrate using the same - Patents.com

JP2024531289A5Pending Publication Date: 2025-08-26BASF CORPORATON
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Patent Information

Application Number
JP2024509025
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Priority Date
2021-08-19
Filing Date
2022-08-18
Publication Date
2025-08-26

AI Technical Summary

Technical Problem

Existing wall flow filters face challenges in achieving superior filtration efficiency while maintaining low backpressure, particularly under stringent emission regulations like Euro 6d and China 6b, necessitating improved coating systems and processes for large-scale production.

Method used

A coating system comprising a charging unit, transport unit, receiving unit, and control unit, with precise material dosing and conveying mechanisms, including check valves, gas buffers, and adjustable holders, to ensure accurate and stable application of coating materials onto substrates.

Benefits of technology

The system enables the production of filters with enhanced particulate matter trapping efficiency and reduced backpressure, meeting stringent emission goals without further modifications, and allows for large-scale manufacturing.

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Abstract

A coating system for coating a substrate (10), comprising: an input unit (1) for pre-weighing and inputting a solid material to be transported; a transport unit (2) for transporting the metered solid material to the substrate (10) to be coated by a transport gas flow; a receiving unit (3) for receiving the substrate, the receiving unit (3) being located downstream of the transport unit along a flow direction (F) of the transport gas flow; and a control unit (4) for controlling the operation of the input unit (1), the transport unit (2), and the receiving unit (3).
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Description

[Technical field]

[0001] The present invention relates to a coating system for coating a substrate, particularly a substrate for a wall-flow filter, and a process for coating a substrate with the coating system. [Background technology]

[0002] Certain internal combustion engines, such as lean burn engines, diesel engines, natural gas engines, power plants, incinerators, and gasoline engines, tend to produce exhaust gases having significant amounts of soot and other particulate matter. Typically, particulate matter emissions can be improved by passing the PM-containing exhaust gases through a wall-flow filter.

[0003] Diesel wall-flow filters have proven to be efficient in removing carbon soot from diesel engine exhaust gases. The most widely used diesel particulate filters are wall-flow filters, which filter diesel exhaust gases by trapping soot on the porous walls of the filter body. Wall-flow filters are designed to provide near complete filtration of soot without significantly impeding the exhaust flow.

[0004] There is a need to provide improved coating systems and processes for obtaining filters, such as wall-flow filters, with excellent filtration efficiency and low back pressure.

[0005] Recently, even more stringent regulations such as Euro 6d and China 6b have been imposed, and traditional catalytic filter technology, without further improvements, cannot simultaneously meet customer emission targets for particulate matter and backpressure targets for exhaust systems. This has created an urgent need to develop next generation catalytic filters (or FWCs) and at the same time develop new coating systems that can produce this next generation product on a large scale. Summary of the Invention

[0006] It is an object of the present invention to provide an improved coating system for more efficiently producing filters having excellent filtration efficiency and low back pressure.

[0007] Another object of the present invention is to provide an improved coating process for more efficiently producing filters having excellent filtration efficiency and low back pressure.

[0008] Therefore, one aspect of the present invention relates to a coating system for coating a substrate, comprising an input unit for pre-metering and inputting a solid material to be transported, a transport unit for transporting the metered solid material to the substrate to be coated by a transport gas flow, a receiving unit for receiving the substrate, the receiving unit being located downstream of the transport unit along the flow direction of the transport gas flow, and a control unit for controlling the operation of the input unit, the transport unit and the receiving unit.

[0009] In an embodiment, the input unit may include an automatic material input device comprising a material container having a dispensing port and a dispensing mechanism disposed within the material container, a material transfer container, and a metering device, wherein the dispensing mechanism is used to dispense solid material into the material transfer container through the dispensing port, and the metering device is used to meter the solid material in the material transfer container.

[0010] In an embodiment, the dispensing mechanism and the metering device may each communicate with a control unit, which receives a weight measurement of the solid material dispensed into the material transfer container from the metering device, compares the weight measurement with a set weight of the solid material being transported, and if the weight measurement is within ±5% of the set weight, the control unit controls the dispensing mechanism to stop dispensing of the solid material.

[0011] In an embodiment, the conveying unit includes a conveying pipe having an inlet end and an outlet end, and a first check valve and a second check valve are provided between the conveying pipe and the outlet end; a fan for generating a conveying gas flow from the outlet end of the conveying pipe to a receiving unit; and a connecting pipeline that places the fan in fluid communication with the outlet end of the conveying pipe and the receiving unit.

[0012] Preferably, the conveying pipe may be arranged vertically, and its inlet end is funnel-shaped, and the conveying unit may further include a gas buffer box arranged between the fan and the conveying pipe, a cooler arranged between the fan and the gas buffer box, a first control valve provided between the cooler and the gas buffer tank, a second control valve provided between the gas buffer box and the conveying pipe, and a branch pipe provided between the cooler and the first control valve, fluidly connecting the connecting pipeline with the external environment, and a third control valve is disposed in the branch pipe.

[0013] In an embodiment, the receiving unit may comprise a holding mechanism for fixedly holding the substrate, the holding mechanism being airtightly connected to the fan by a connecting pipeline.

[0014] Preferably, the holding mechanism is an expandable flexible holder that can be adjusted to hold substrates of different sizes.

[0015] In an embodiment, the connecting pipeline may comprise a first pipe section connected to the outlet end of the fan and conveying pipe and having a first cross-section, and a second tapered pipe section connected to the receiving unit, the minimum cross-section of the second tapered pipe section being equal to the first cross-section and the maximum cross-section of the second tapered pipe section being defined as a second cross-section that is equal to or greater than the cross-section of the substrate.

[0016] In an embodiment, the diameter of the first cross section may be in the range of 0.3D to 0.75D, preferably 0.4D to 0.6D. The maximum diameter of the second cross section may be in the range of 1D to 1.2D, preferably 1.02D to 1.1D. The height of the second tapered pipe section may be in the range of 0.3D to 0.9D, preferably 0.4D to 0.8D, where D means the diameter of the circular cross section of the substrate or the minor axis of the elliptical cross section of the substrate if the substrate is an elliptical cylinder.

[0017] Those skilled in the art will appreciate that a cylinder has a circular cross-section and an elliptical cylinder has an elliptical cross-section.

[0018] In an embodiment, when the D of the substrate is in the range of 95 mm to 155 mm, the diameter of the first cross section may be in the range of 60 mm to 100 mm, for example 60 mm or 100 mm, the maximum diameter of the second cross section may be in the range of 96 to 160 mm, for example 98 or 155 mm, and the height of the second tapered pipe section may be in the range of 60 mm to 130 mm.

[0019] In another embodiment, the connecting pipeline may comprise a first pipe section connected to the outlet end of the fan and the conveying pipe and having a first cross section, a second tapered pipe section connected to the receiving unit, and a third pipe section connecting the first pipe section to the second tapered pipe section, the third pipe section being connected to the first pipe section by its tapered connecting portion, the maximum cross section of the second tapered pipe section being defined as a second cross section, the second cross section being equal to or greater than the cross section of the substrate, and the cross section of the third pipe section being defined as a third cross section, the third cross section being greater than the first cross section and equal to the minimum cross section of the second tapered pipe section.

[0020] In an embodiment, the substrate may be a filter substrate, in particular a substrate for a wall-flow filter having an inlet side and an outlet side, and the substrate is placed in an expandable flexible holder with its inlet side facing the transport unit.

[0021] Preferably, the coating system according to the present invention may further comprise an automated transfer mechanism for transferring the substrate to be coated to the receiving unit and for removing the coated substrate from the receiving unit.

[0022] The present invention also relates to a process for coating a substrate in the above coating system, which may include the steps of providing a substrate, holding the substrate fixedly in a receiving unit, pre-metering a solid material to be coated on the substrate by an input unit, mixing the metered solid material with a carrier gas flow and transporting it to the receiving unit by a transport unit to coat the substrate, and removing the coated substrate from the receiving unit.

[0023] In the above process, the substrate can be a substrate for a wall-flow filter.

[0024] The coating system according to the present invention can simultaneously meet the customer's emission target for particulate matter and the back pressure target for the exhaust system without further modification. The product (catalyzed filter) obtained by this new coating system has a higher capture efficiency for particulate matter, and at the same time, the coating system can produce this product on a large scale. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 shows a schematic block diagram of one embodiment of a coating system according to the present invention. [Diagram 2] 1 shows a schematic structural diagram of an input unit according to the present invention; [Diagram 3] FIG. 2 is a schematic diagram showing a transport unit and a receiving unit connected to each other. [Figure 4] FIG. 2 is a schematic structural diagram showing a conveying pipe and a connecting pipeline connected to each other. [Diagram 5]2 is a schematic diagram showing an embodiment of a connection section for connecting a conveying pipe to a receiving unit according to the invention; FIG. [Figure 6] FIG. 4 is a schematic diagram showing another embodiment of a connection section for connecting a conveying pipe to a receiving unit according to the invention; [Figure 7] FIG. 1 is a schematic diagram showing an embodiment of a wall-flow filter substrate according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The undefined articles "a," "an," and "the" refer to one or more of the species designated by the term following the article.

[0027] In the context of this disclosure, any specific values ​​recited for a characteristic (including the specific values ​​recited in a range as an endpoint) can be recombined to form new ranges.

[0028] In the context of the present disclosure, each aspect so defined may be combined with other aspects unless expressly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0029] FIG. 1 shows a schematic block diagram of one embodiment of a coating system for coating a substrate 10 according to the present invention. The coating system mainly includes an input unit 1, a transport unit 2, a receiving unit 3, and a control unit 4 for controlling the operation of the input unit 1, the transport unit 2, and the receiving unit 3. The input unit 1 is used to pre-meter and input the solid material to be transported, and the transport unit 2 is used to transport the metered solid material to the substrate 10 to be coated by the carrier gas flow. In addition, the receiving unit 3 is used to receive the substrate and is located downstream of the transport unit along the flow direction F of the carrier gas flow. In the present invention, the substrate can be a substrate for a particulate filter, in particular a wall-flow filter. However, a person skilled in the art should understand that it can also be other types of substrates that need to be coated.

[0030] In a preferred embodiment, as shown in Fig. 2, the dosing unit 1 may comprise an automatic material dosing device 11, a material transfer container 15, and a metering device 16. As can be seen, the automatic material dosing device 11 is configured to include a material container 13 having a distribution port (or distribution tube) 12, and a distribution mechanism 14 arranged in the material container. The solid material to be transported is contained in the material container, and the distribution mechanism 14 is used to distribute the solid material through the distribution port 12 into a material transfer container 15 such as a cup, and the solid material in the material transfer container is metered by the metering device. In an embodiment, the distribution mechanism 14 may be, for example, a screw mechanism for pushing the solid material into a distribution pipe arranged at an angle.

[0031] In the above-mentioned input unit 1, the dispensing mechanism 14 and the weighing device 16 each communicate with the control unit 4, which receives a weight measurement W1 of the solid material to be dispensed into the material transfer container from the weighing device 16, compares the weight measurement W1 with a set weight W of the solid material to be transported, and if the weight measurement W1 is within a range of the set weight W ±5%, the control unit 4 controls the dispensing mechanism 14 to stop dispensing the solid material.

[0032] In actual operation, the weight measurement W1 of the solid material is the weight measurement Wt of the weighing device 16 minus the weight Wc of the material transfer container 15. Because it is difficult to avoid some solid material sticking to the wall of the material transfer container 15, after the solid material in the material transfer container 15 is fed into the conveying unit 2, the empty material transfer container 15 needs to be placed on the weighing device 16 and weighed again, the measured value is Wr, and then Wt-Wr is the actual material weight G fed into the conveying unit 2. If the actual material weight G is within a certain range, for example within the set weight W±5%, the input unit 1 will continue to weigh the solid material for the next substrate, otherwise the weighing device 16 will send a signal to the control unit to mark the substrate coated this time as "defective".

[0033] In an embodiment according to the present invention, as shown in FIG. 3, the conveying unit 2 may comprise a fan 5, a conveying pipe 21, and a connecting pipeline 22 fluidly connecting the fan 5 with the outlet end 21b of the conveying pipe and the receiving unit 3.

[0034] 4, the conveying pipe 21 having an inlet end 21a and an outlet end 21b is arranged vertically, and the inlet end 21a is preferably funnel-shaped. Between the inlet end and the outlet end of the conveying pipeline 21, a first check valve (one-way valve) V1 and a second check valve V2 may be provided, and the first check valve V1 and the second check valve V2 are respectively communicated with the control unit 4, and the opening and closing of these valves is controlled by the control unit 4. For example, the first check valve V1 at the top of the conveying pipe 21 can be opened first, and the solid material can be fed from the material transfer container 15 into the conveying pipe 2, then the first check valve V1 is closed, and finally the second check valve V2 is opened. Under the action of gravity, the solid material is conveyed into the conveying pipeline 22 and conveyed to the receiving unit 3 by the conveying air flow from the fan 5. The main purpose of providing two check valves is to prevent the solid material from being blown away by the reverse conveying air flow from the fan 5 as it is pumped into the conveying pipe 21, resulting in loss of the solid material.

[0035] Referring again to FIG. 3, in order to maintain the stability of the conveying air flow, the conveying unit 2 further comprises a gas buffer box 23 arranged between the fan 5 and the conveying pipe 21. In order to prevent the fan from overheating, a cooler 24 is provided between the fan 5 and the gas buffer tank 2. In addition, a first control valve 25 is provided between the cooler 24 and the gas buffer box 23, and a second control valve 26 is provided between the gas buffer box 23 and the conveying pipe 21 to control the speed of the conveying gas flow. Furthermore, a branch pipe 27 may be further arranged between the first control valve 25 and the cooler 24, which can put the connecting pipe 22 in fluid communication with the outside environment, and a third control valve 28 is arranged in the branch pipe 27, which may be fully or partially opened when the coating system is operating, in order to control the flow rate of the conveying air flow in the conveying unit 2. In order to control the stability of the coating process, a flow sensor 29 may also be provided downstream of the second control valve 26 in the connecting pipe 22 to monitor the flow rate of the conveying air flow.

[0036] According to an embodiment of the present invention, as shown in Fig. 5, the receiving unit 3 may comprise a holding mechanism 31 for fixedly holding the substrate 10 to be coated, which may be airtightly connected to the fan 5 by a connecting pipe 22. Advantageously, the holding mechanism 31 is an inflatable flexible holder that can be adjusted to accommodate substrates 10 of different sizes. For example, the inflatable flexible holder may be in the form of a life jacket or a tire.

[0037] 7, in the present invention, the substrate 10 is, for example, a wall-flow filtration substrate, and has an inlet side 10a and an outlet side 10b, and the substrate 10 is placed in an expandable flexible holder with its inlet side 10a facing the transport unit 2, in other words, with its inlet side 10a facing the connecting pipe 22. The substrate shown in this figure has a circular cross section, and the cross-sectional diameter (D) of the relatively small size substrate can be, for example, in the range of 95 mm to 155 mm, and the cross-sectional diameter (D) of the relatively large size substrate can be, for example, in the range of 160 mm to 350 mm.

[0038] In an embodiment not shown, the cross section of the substrate may be elliptical, in which case the minor axis (D) of the elliptical cross section of the relatively small size substrate may be in the range of 95 mm to 155 mm, and the minor axis (D) of the cross section of the relatively large size substrate may be in the range of 160 mm to 350 mm.

[0039] Referring again to FIG. 5, this is a schematic structural diagram showing an embodiment of a connection section of a connecting pipeline 22 for connecting a conveying pipe 21 to a receiving unit 3 according to the present invention.

[0040] As can be seen in Figures 3 and 5, the connecting pipeline 22 comprises a first pipe section 22a connected to the fan 5 and the outlet end 21b of the conveying pipe and having a first cross section, and a second tapered pipe section 22b connected to the receiving unit 3, the minimum cross section of the second tapered pipe section being equal to the first cross section and the maximum cross section of the second tapered pipe section being defined as a second cross section that is equal to or greater than the cross section of the substrate 10.

[0041] The aforementioned configuration of the connection section of the connection pipeline shown in Fig. 5 is particularly suitable for small sized substrates, for example, the diameter / minor axis (D) of the cross section of the substrate 10 is in the range of 95mm to 155mm. In this case, the diameter of the first cross section may be in the range of 0.3D to 0.75D, preferably 0.4D to 0.6D, for example, 60mm to 100mm, the maximum diameter of the second cross section may be in the range of 1D to 1.2D, preferably 1.02D to 1.1D, for example, 95mm to 155mm, and the height of the second tapered pipe section 22b may be in the range of 0.3D to 0.9D, preferably 0.4D to 0.8D, for example, 60mm to 130mm.

[0042] Figure 6 is a schematic structural diagram showing another embodiment of the connection section of the connecting pipeline 22 for connecting the conveying pipe 21 to the receiving unit 3 according to the present invention. The aforementioned configuration of the connection section of the connecting pipeline shown in Figure 6 is particularly suitable for large size substrates, for example, the diameter / minor axis (D) of the cross section of the substrate is in the range of 160mm-350mm.

[0043] In this embodiment, the connecting pipeline 22 comprises a first pipe section 22a connected to the fan 5 and the outlet end 21b of the conveying pipe and having a first cross section, a second tapered pipe section 22b connected to the receiving unit 3, and a third pipe section 22c connecting the first pipe section 22a to the second tapered pipe section 22b, the third pipe section being connected to the first pipe section 22b by its tapered connecting part 22d, the maximum cross section of the second tapered pipe section being defined as the second cross section, the second cross section being equal to or greater than the cross section of the substrate 10, and the cross section of the third pipe section being defined as the third cross section, the third cross section being greater than the first cross section and equal to the minimum cross section of the second tapered pipe section. For example, in one embodiment, the diameter of the first cross section may be 0.17D to 0.375D, the diameter of the third cross section may be 0.28D to 0.625D, and the diameter of the second cross section may be equal to or greater than D. Specifically, the diameter of the first cross section may be 60 mm, the diameter of the third cross section may be 100 mm, and the diameter of the second cross section may be 350 mm.

[0044] 5, the coating system according to the present invention may further comprise an automated transfer mechanism 6 for transferring the substrate 10 to be coated to the receiving unit and for removing the coated substrate from the receiving unit, where the automated transfer mechanism 6 may be a robot.

[0045] The present invention also relates to a process for coating a substrate 10 with the above-mentioned coating system to obtain a product such as a wall-flow filter, the process comprising the steps of providing a substrate 10, holding the substrate fixedly in a receiving unit 3, pre-weighing a solid material to be coated on the substrate by an input unit 1, mixing the weighed solid material with a carrier gas flow and transporting it to the receiving unit 3 by a transport unit 2 to coat the substrate, and removing the coated substrate from the receiving unit 3.

[0046] In the step of providing the substrate 10, a scanning device (not shown) may be provided to scan the provided substrate to determine whether the batch of substrates is correct, if so, the substrate is fixed and held in the receiving unit 3, if not, the substrate is determined to be a rejected substrate.

[0047] In the step of pre-weighing the solid material to be coated on the substrate by the input unit 1, the weight G of the solid material actually fed into the transport unit 2 can also be measured by the weighing device 16 and sent to the control unit for comparison with the set weight W. If G is within the range of the set weight W±5%, the measuring unit continues to weigh the solid material for the next substrate, otherwise it sends a signal to the control unit to mark the coated substrate as a rejected product.

[0048] In the step of mixing the metered solid materials with the carrier gas flow and transporting them to the receiving unit 3 to coat the substrate by the transport unit 2, the flow rate of the carrier gas flow can be controlled by the first control valve, the second control valve, and the third control valve.

[0049] To produce a resultant product with suitable product properties and appearance, carrier gas streams with different flow rates can be provided to substrates with different sizes. For example, for a substrate with a cross-sectional diameter or minor axis of less than 100 mm, the flow rate of the carrier air stream is 600±40 m / s. 3 For a substrate having a cross-sectional diameter or minor axis in the range of 100 mm to 160 mm, the flow rate of the conveying air stream can be selected as 300 m 3 / hour~800m 3 For larger sized substrates, the flow rate of the transport air stream can be selected to be in the range of 500 m 3 / hour~1000m 3 / hour range. In addition, it is necessary to use a suitable flow rate of carrier gas flow to purge the substrate to be coated for a certain period of time, for example 20 seconds, during coating. If the flow rate is not suitable and the purge time is not sufficient, the resulting product may be unacceptable.

[0050] After the step of removing the coated substrate from the receiving unit 3, it is possible to determine whether the obtained product is qualified by a back pressure test. For example, if the back pressure of the desired product is P and the measured back pressure Pt=P(1±5%), the product can be judged as good, otherwise it can be judged as unqualified (defective).

[0051] Various modifications and variations conceivable by those skilled in the art may be made to the above disclosed embodiments without departing from the scope or spirit of the present disclosure. Other embodiments will be apparent to those skilled in the art from the present disclosure. The present specification and its disclosed examples should be considered as merely illustrative, and the scope of protection of the present disclosure should be defined by the appended claims and their equivalents.

Claims

1. A coating system for coating a substrate (10), comprising: a dosing unit (1) for pre-weighing and dosing the solid material to be conveyed; a transport unit (2) for transporting the metered solid material to the substrate (10) to be coated by a transport gas flow; a receiving unit (3) for receiving the substrate, the receiving unit (3) being located downstream of the transport unit along the flow direction (F) of the transport gas flow; a control unit (4) for controlling the operation of the input unit (1), the transport unit (2), and the receiving unit (3).

2. The input unit (1) an automatic material input device (11) comprising a material container (13) having a dispensing port (12) and a dispensing mechanism (14) disposed within the material container; a material transfer container (15); a metering device (16), 2. The coating system of claim 1, wherein the dispensing mechanism (14) is used to dispense the solid material through the dispensing port (12) into the material transfer container (15), and the metering device is used to meter the solid material in the material transfer container.

3. 3. The coating system of claim 2, wherein the dispensing mechanism and the metering device each communicate with the control unit, the control unit receives a weight measurement of the solid material dispensed into the material transfer container from the metering device, compares the weight measurement with a set weight of the solid material being transported, and when the weight measurement is equal to the set weight, the control unit controls the dispensing mechanism to stop dispensing the solid material.

4. The transport unit (2) a conveying pipe (21) having an inlet end (21a) and an outlet end (21b), wherein a first check valve (V1) and a second check valve (V2) are provided between the inlet end and the outlet end; a fan (5) for generating a flow of carrier gas from the outlet end (21b) of the carrier pipe to the receiving unit (3); A coating system according to any one of claims 1 to 3, comprising a connecting pipeline (22) that fluidly connects the fan (5) with the outlet end (21b) of the conveying pipe and the receiving unit (3).

5. the conveying pipe is arranged vertically and its inlet end (21a) is funnel-shaped; The transport unit (2) a gas buffer box (23) arranged between the fan (5) and the conveying pipe (21); a cooler (24) disposed between the fan (5) and the gas buffer box (23); a first control valve (25) provided between the cooler and the gas buffer tank; a second control valve (26) provided between the gas buffer box (23) and the conveying pipe (21); 5. The coating system of claim 4, further comprising a branch pipe (27) provided between the cooler (24) and the first control valve (25) for fluidly connecting the connecting pipeline (22) with an external environment, wherein a third control valve (28) is disposed in the branch pipe (27).

6. The receiving unit (3) 5. The coating system according to claim 4, further comprising a holding mechanism (31) for fixedly holding the substrate (10), the holding mechanism (31) being airtightly connected to the fan (5) by the connecting pipeline (22).

7. 7. The coating system of claim 6, wherein the holding mechanism (31) is an expandable flexible holder that can be adjusted to hold different sizes of the substrate.

8. 8. The coating system according to claim 7, wherein the connecting pipeline (22) comprises a first pipe section (22a) connected to the fan (5) and the outlet end (21b) of the conveying pipe and having a first cross section, and a second tapered pipe section (22b) connected to the receiving unit (3), the smallest cross section of the second tapered pipe section being equal to the first cross section and the largest cross section of the second tapered pipe section being defined as a second cross section that is equal to or greater than the cross section of the substrate (10).

9. 9. The coating system of claim 8, wherein the diameter of the first cross section is in the range of 0.3D to 0.75D, preferably 0.4D to 0.6D, the maximum diameter of the second cross section is in the range of 1D to 1.2D, preferably 1.02D to 1.1D, and the height of the second tapered pipe section 22b is in the range of 0.3D to 0.9D, preferably 0.4D to 0.8D, and when the substrate is an elliptical cylinder, D means the diameter of the circular cross section of the substrate or the minor axis of the elliptical cross section of the substrate.

10. 8. The coating system according to claim 7, wherein the connecting pipeline (22) comprises a first pipe section (22a) connected to the fan (5) and the outlet end (21b) of the conveying pipe and having a first cross section, a second tapered pipe section (22b) connected to the receiving unit (3), and a third pipe section (22c) connecting the first pipe section (22a) to the second tapered pipe section (22b), the third pipe section being connected to the first pipe section (22b) by its tapered connecting part (22d), the maximum cross section of the second tapered pipe section being defined as a second cross section, the second cross section being equal to or greater than a cross section of the substrate (10), and the cross section of the third pipe section being defined as a third cross section, the third cross section being greater than the first cross section and equal to the minimum cross section of the second tapered pipe section.

11. 7. The coating system of claim 6, wherein the substrate (10) is a substrate for a wall-flow filter and has an inlet side (10a) and an outlet side (10b), and the substrate (10) is placed in the expandable flexible holder with its inlet side (10a) facing the transport unit (2).

12. 2. The coating system of claim 1, further comprising an automated transfer mechanism (6) for transferring the substrate (10) to be coated to the receiving unit and removing the coated substrate from the receiving unit.

13. A process for coating a substrate (10) with a coating system according to any one of claims 1 to 3, comprising the steps of: providing said substrate (10); holding said substrate fixedly in a receiving unit (3); Pre-weighing the solid material to be coated onto the substrate by a dosing unit (1); mixing the metered solid material with the carrier gas flow and transporting it by the transport unit (2) to the receiving unit (3) to coat the substrate; Removing the coated substrate from the receiving unit (3).

14. The process of claim 13, wherein the substrate (10) is a substrate for a wall-flow filter.