CN111250358A

CN111250358A - Automatic coating system and coating process for catalyst slurry

Info

Publication number: CN111250358A
Application number: CN202010241176.1A
Authority: CN
Inventors: 邓崴
Original assignee: Zhenjiang Sitai Intelligent Equipment Technology Co Ltd
Current assignee: Zhenjiang Sitai Intelligent Equipment Technology Co Ltd
Priority date: 2019-07-12
Filing date: 2020-03-31
Publication date: 2020-06-09
Also published as: CN211838832U; CN211838831U

Abstract

The invention discloses an automatic catalyst slurry coating system and a coating process, wherein the coating system comprises a slurry supply device, an upper coating cavity, a lower coating cavity, a suck-back device, a transfer device, a first weighing device, a second weighing device and a third weighing device; the slurry supply device comprises a slurry tank and a flowmeter; the upper coating cavity and the lower coating cavity are connected with a slurry tank, the upper coating cavity and the lower coating cavity are arranged in a one-to-one correspondence manner, a space for accommodating a catalyst carrier is formed between the upper coating cavity and the lower coating cavity, and the slurry tank conveys slurry to the catalyst carrier through the upper coating cavity or the lower coating cavity; the first weighing device is used for metering the original weight of the catalyst carrier to be coated with the slurry, and the second weighing device is used for metering the weight of the catalyst carrier after one coating of the slurry. The automatic coating system can be selected according to the characteristics of slurry to be coated, can be used for coating catalytic slurry on different catalyst carriers, and can meet different requirements; the accuracy and uniformity of slurry coating in the carrier can be ensured.

Description

Automatic coating system and coating process for catalyst slurry

Technical Field

The invention relates to the field of catalyst slurry coating process devices, in particular to an automatic catalyst slurry coating system and a coating process.

Background

The automobile catalyst is the most effective and key automobile part for reducing harmful substances in automobile exhaust by adopting an effective catalytic purification technology. The automobile catalyst is a series of chemical material complex, and is composed of four portions of catalyst carrier, coating, catalyst adjuvant and active component.

The catalyst coating is the second process of catalyst production and is also the most critical link. Based on two main reaction functions of oxidation catalysis and reduction catalysis, and aiming at tail gas components under different working conditions, different products such as TWC, DOC, SCR, DPF, POC, ASC and the like are derived from the automobile catalyst, and the slurry characteristics, the coating modes and the coating parameters required by the different products are completely different. The various slurries of the catalyst have wide characteristics, and comprise both non-Newtonian fluid slurry with high solid content and thin slurry with low suspension characteristic and weak viscoelastic characteristic. Meanwhile, the physical properties of the raw materials of the catalyst are greatly changed, so that the granularity of the materials is greatly reduced, the chemical activity of the catalyst is increased, and the number of coating layers of each catalyst carrier is greatly increased.

Because the carrier has thousands of pore channels, if the thickness of the catalyst coating in each pore channel is inconsistent or the coating height is inconsistent, the catalytic purification effect when the waste gas flows through the catalyst pore channels is inconsistent, and the purification rate is reduced, which are called as uneven coating.

The traditional coating process is complex in operation process, needs a large amount of manual mold changing operation, and is long in coating mold changing time and low in efficiency. At present, a domestic catalyst coating system can only meet a certain specific coating mode generally, and has the disadvantages of long period from design to installation and debugging, high cost ratio and limited later-period expansion capability. Once a production enterprise needs to expand the product types or the capacity according to the development of the enterprise, a new coating system needs to be customized again, so that the investment cost of the enterprise is increased, time and labor are consumed, and a large amount of production space is occupied.

At present, domestic coating equipment generally has low coating precision and poor repeatability, and has a relatively obvious technical bottleneck under the national six standards, and particularly has a possible nonuniform coating phenomenon on large-size carriers (more than 300 mm) and non-through-hole carriers (such as DPF).

At present, compressed air is adopted in part of domestic coating processes for blowing, the compressed air leaks, slurry is seriously wasted, and the slurry cannot be effectively and reasonably recovered; air energy consumption is large, and technological parameter adjustment cannot be automatically carried out.

At present, the domestic quantitative feeding coating process has high requirements on slurry characteristics, carrier characteristics and the like, and has large use limit. In particular, effective control cannot be performed with respect to the uniformity of the half-coating, with the risk of possible clogging and excessive backpressure.

In addition, because the research and development of enterprises on catalyst products are enhanced, catalysts with various novel formulas are put into the market, the enterprises often cannot confirm the coating mode and coating parameters according to the traditional experience, the advantages and the characteristics of the original coating equipment cannot be exerted, and the quality instability, the efficiency reduction and the material loss are caused.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an automatic catalyst slurry coating system and a coating process, which can ensure the uniformity and the accuracy of catalyst coating, and the technical scheme is as follows:

in one aspect, the present invention provides an automatic catalyst slurry coating system for coating a catalyst slurry into a catalyst carrier, the coating system comprising a slurry supply device, one or more upper coating chambers, one or more lower coating chambers, a suck-back device connected to the lower coating chambers, a transfer device for transferring a catalyst carrier, a first weighing device, a second weighing device and a third weighing device for measuring the weight of the catalyst carrier;

the slurry supply device comprises a slurry tank and a flow meter, wherein the flow meter is used for metering the volume of the slurry conveyed from the slurry tank to the upper coating cavity or the lower coating cavity;

the automatic coating system is provided with a coating state, when the automatic coating system is in the coating state, the upper coating cavity and the lower coating cavity are arranged in a one-to-one correspondence mode, a space for accommodating a catalyst carrier is formed between the upper coating cavity and the lower coating cavity, and the slurry tank conveys slurry to the catalyst carrier through the upper coating cavity or the lower coating cavity;

the first weighing device and the second weighing device are respectively arranged on two sides of a lower coating cavity, the first weighing device is used for metering the original weight of the catalyst carrier to be coated with the slurry, and the second weighing device is used for metering the weight of the catalyst carrier coated with the slurry for one time; the third weighing device and the second weighing device are arranged on two sides of the other lower coating cavity and are used for metering the weight of the catalyst carrier after the slurry is coated for the second time;

the suck-back device is used for discharging slurry from the lower coating cavity.

Further, the upper coating cavity comprises an upper coating table, an upper cavity for accommodating one end of the catalyst carrier is formed in the upper coating table, an annular screen and a first sealing ring arranged below the screen are arranged on the inner wall of the upper cavity, and the first sealing ring is arranged along the outer side wall of the upper cavity;

the lower coating cavity comprises a lower coating platform, a lower cavity used for containing the other end part of the catalyst carrier is arranged on the lower coating platform, a second sealing ring of a hollow structure is arranged on the outer side wall of the lower cavity, and the first sealing ring and the second sealing ring are used for synchronously clamping the catalyst carrier when the catalyst carrier is arranged between the upper cavity and the corresponding lower cavity.

Further, go up the coating chamber and include coating chamber on first coating chamber and the second, coating chamber down including be used for once coating thick liquids with first coating chamber that first coating chamber set up relatively, be used for the secondary coating thick liquids with coating chamber relatively set up's second coating chamber under the second on the second, first weighing device, first coating chamber, second weighing device, second coating chamber and third weighing device set up side by side in proper order.

Furthermore, a stirring device is arranged in the slurry tank, a plurality of slurry feeding ports and a plurality of feed back ports are arranged on the slurry tank, the feeding ports are connected with a feeding pump through pipelines, the feed back ports are connected with a feed back pump through pipelines, and switching valve ports are fixedly arranged on the pipelines; the outer surface of the slurry tank is provided with a jacket layer, an accommodating cavity is formed between the jacket layer and the slurry tank, and the jacket layer is provided with a temperature sensor which can extend into the slurry tank;

further, still be provided with level sensor, density sensor and viscosity sensor on the thick liquids jar, level sensor is used for detecting the capacity of thick liquids in the thick liquids jar, density sensor is used for detecting the density of thick liquids in the thick liquids jar, viscosity sensor is used for detecting the viscosity of thick liquids in the thick liquids jar.

Further, the automatic catalyst slurry coating system further comprises a drying device for heating the catalyst carrier of the slurry to be coated, wherein the drying device is provided with a preheating cavity for accommodating the catalyst carrier and a hot air blower for providing heat and blowing the heat to the preheating cavity.

The slurry supply device further comprises a delivery pump and a pressure stabilizing valve, wherein the delivery pump is used for delivering the slurry in the slurry tank to the upper coating cavity or the lower coating cavity through a connecting hose, and the pressure stabilizing valve is arranged at the tail end of an outlet pipeline of the delivery pump; the back suction device comprises a vacuum tank connected with the lower coating cavity and a vacuum pump connected with the vacuum tank;

the transfer device comprises a mechanical arm, a drag chain arranged on the mechanical arm, a driving mechanism used for driving the drag chain to move and a plurality of mechanical claws, the drag chain can drive the mechanical claws to move, and one upper coating cavity can be fixedly connected with one mechanical claw, so that the upper coating cavity can move along with the mechanical claws.

On the other hand, the invention also provides a coating process based on the automatic catalyst slurry coating system, which comprises a twice coating process, wherein the twice coated slurry respectively enters the catalyst carrier through 2 different upper coating cavities; or the slurry coated twice enters the catalyst carrier through 2 different lower coating cavities respectively; or the slurry coated for the first time firstly enters the catalyst carrier through the upper coating cavity, and the slurry coated for the second time enters the catalyst carrier through the lower coating cavity; or the slurry coated for the first time firstly enters the catalyst carrier through the lower coating cavity, and the slurry coated for the second time enters the catalyst carrier through the upper coating cavity.

The two-time coating process comprises the following steps:

s1, setting a preset first capacity threshold range of slurry to be coated and a preset qualified weight and a qualified range of the catalyst carrier;

s2, measuring the original weight of the catalyst carrier before coating by a first weighing device;

s3, feeding the slurry into a catalyst carrier for primary coating, and measuring the primary coating by a second weighing device to obtain the first weight of the catalyst carrier;

s4, judging whether the first weight of the catalyst carrier after primary coating is in a qualified range, if not, executing a step S5; if so, the weight of the catalyst carrier is qualified;

s5, calculating the difference between the qualified weight and the first weight, and if the difference is zero, determining that the weight of the catalyst carrier is qualified; if the difference is positive, i.e. the first weight is lower than the qualified weight, go to step S6; if the difference is negative, i.e. the first weight is higher than the qualified weight, go to step S8;

s6, calculating a preset second capacity threshold range of slurry required by secondary coating, feeding the slurry into the catalyst carrier for secondary coating, and measuring the weight of the catalyst carrier after the secondary coating by using a third weighing device to obtain a second weight;

s7, judging whether the second weight of the catalyst carrier after the secondary coating in the step S6 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, the weight of the coated catalyst carrier is unqualified, the deviation percentage of the unqualified weight is calculated, and the slurry required by secondary coating in the step S6 is adjusted according to a preset calculation formula;

s8, starting a back suction device, discharging slurry exceeding a preset qualified range, and measuring the weight of the catalyst carrier after the slurry is discharged by using a third weighing device to obtain a third weight;

s9, judging whether the third weight of the catalyst carrier after the slurry is discharged in the step S8 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, the weight of the catalyst carrier is unqualified, the deviation percentage of the unqualified weight is calculated, and the operation parameters of the back suction device in the step S8 are adjusted according to a preset calculation formula.

Furthermore, according to the viscosity of different catalyst slurry or the mesh number or coating proportion of the catalyst carrier, an optimized coating mode can be selected,

if the viscosity of the catalyst slurry is high, or the mesh number of the catalyst carrier is low, or the catalyst carrier is completely coated, the catalyst slurry enters the catalyst carrier from top to bottom through the upper coating cavity, namely, the coating mode is selected, and a product with optimized uniformity and precision is obtained;

if the viscosity of the catalyst slurry is small, or the mesh number of the catalyst carrier is high, or the catalyst carrier is partially coated, the catalyst slurry enters the catalyst carrier from bottom to top through the lower coating cavity, namely a lower coating mode is selected, and a product with optimized uniformity and accuracy is obtained.

The technical scheme provided by the invention has the following beneficial effects:

a. the catalyst slurry automatic coating system can ensure the accuracy and uniformity of carrier coating and can also avoid the deviation of temperature, viscosity, density and concentration before and after slurry in the whole coating process;

b. the coating system and the coating process can meet the coating requirements of various national six catalysts and ensure the coating performance of the catalysts;

c. the coating system can be completely suitable for automatically coating various catalyst slurry with multiple characteristics; the equipment has a compact structure, is fully automatically operated, and can maximally utilize the energy production requirement of the equipment; the rapid model changing design is adopted to meet the model changing production of various catalysts; the characteristics of various carriers and slurry are automatically compensated, the production efficiency is improved, and the labor intensity and health damage of operators are reduced;

d. the coating process can finish the coating of the catalyst slurry in a short time, automatically correct process deviation, ensure the precision of the coating slurry, reduce material leakage and loss, improve the production efficiency and have simple operation.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a perspective view of an automatic catalyst slurry coating system provided by an embodiment of the present invention;

fig. 2 is a front view of an automatic catalyst paste coating system according to an embodiment of the present invention;

FIG. 3 is a left side view of an automatic catalyst slurry coating system provided by an embodiment of the present invention;

FIG. 4 is a top view of an automated catalyst slurry coating system provided by an embodiment of the present invention;

FIG. 5 is a side view of an upper coating chamber of an automatic catalyst slurry coating system according to an embodiment of the present invention;

FIG. 6 is a side view of a lower coating chamber of an automated catalyst slurry coating system provided by an embodiment of the present invention;

fig. 7 is a structural view of a slurry tank of the automatic catalyst slurry coating system according to the embodiment of the present invention;

fig. 8 is a flowchart of a method for using a double coating of an automatic catalyst slurry coating system according to an embodiment of the present invention.

Wherein the reference numerals include: 1-a slurry supply device, 11-a slurry tank, 111-a liquid level sensor, 112-a feed inlet, 113-a viscosity sensor, 114-a jacket layer, 115-a temperature sensor, 116-a stirring device, 12-a delivery pump, 13-a pressure stabilizing valve, 14-a reclaiming pump, 15-a bracket, 16-a flow meter, 17-a connecting pipe, 211-an upper cavity, 212-a screen mesh, 213-a first sealing ring, 214-a first coating valve, 215-a first air source control valve, 216-a material level switch, 221-a lower cavity, 222-a second sealing ring, 223-a vacuum material suction valve, 224-a second coating valve, 225-a second air source control valve, 24-a first upper coating cavity, 25-a first lower coating cavity and 26-a second upper coating cavity, 27-a second lower coating chamber, 3-a suck-back device, 31-a vacuum tank, 32-a vacuum pump, 33-a vacuum sensor, 4-a transfer device, 41-a mechanical arm, 42-a drag chain, 43-a driving mechanism, 44-a mechanical claw, 5-a first weighing device, 6-a second weighing device, 7-a third weighing device, 8-a drying device, 81-a preheating chamber, 82-a hot air blower, and 9-a catalyst carrier.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.

In an embodiment of the present invention, an automatic catalyst slurry coating system is provided, and the specific structure is shown in fig. 1 to 4, which is used for coating catalyst slurry into a catalyst carrier, and includes a slurry supply device 1, one or more upper coating cavities, one or more lower coating cavities, a suck-back device 3 connected to the lower coating cavity, a transfer device 4 for transferring a catalyst carrier, and a first weighing device 5 and a second weighing device 6 for measuring the weight of the catalyst carrier, and a controller connected to the slurry supply device 1, the suck-back device 3, and the transfer device 4.

The catalyst slurry automatic coating system further comprises a drying device 8 for drying a catalyst carrier to be coated, wherein the drying device 8 is provided with a preheating cavity 81 for the catalyst carrier to penetrate in and out and a hot air blower 82 for providing heat and blowing the heat to the preheating cavity 81, the hot air blower 82 is preferably arranged below the preheating cavity 81, the hot air blower and the preheating cavity form a quick blowing preheating station, the catalyst carrier to be coated is subjected to residual moisture pretreatment, the increase of initial weight after the carrier absorbs moisture is prevented, and the coating accuracy and consistency are further ensured.

The concrete structure of the pulp supply device 1 is as follows: the slurry supply device 1 comprises a slurry tank 11, a bracket 15 for supporting the slurry tank 11 and a flow meter 16 for metering the slurry flowing through the slurry supply device, wherein the flow meter 16 is arranged to accurately meter the amount of the slurry delivered to a coating cavity; be provided with the high-efficient agitating unit 116 of multilayer in thick liquids jar 11, do benefit to thick liquids stirring, be provided with a plurality of thick liquids feed inlet and a plurality of feed back mouth on the thick liquids jar 11, the feed inlet passes through the pipeline and is connected with the charge pump, the feed back mouth passes through the pipeline and is connected with feed back pump 14, all fixedly on the pipeline being provided with the switching valve port of taking standard interface, can carry out automatic switch according to the technology demand.

The outer surface of the slurry tank 11 is provided with a jacket layer 114, and an accommodating cavity is formed between the jacket layer 114 and the slurry tank 11, namely the slurry tank 11 is divided into an inner layer and an outer layer, the outer layer is the jacket layer 114 for accommodating water, and the inner layer is a cavity for storing slurry; a temperature sensor 115 extending into the slurry tank 11 is disposed on the jacket layer 114. The jacket layer 114 may be filled with cooling water or hot water for cooling or heating the slurry in the tank, and the cooling water or hot water may be supplied and controlled by pipes and automatic valves to maintain the temperature of the slurry in the slurry tank stable.

Still be provided with level sensor 111, density sensor and viscosity sensor 113 on the thick liquids jar 11, level sensor 111 is used for detecting the level sensor 111 of thick liquids capacity in the thick liquids jar 11, and automatic valve on accessible charge pump and the feed pipeline feeds in accordance with level sensor 111's detection data to maintain the stability of jar thick liquids capacity. The density sensor is used for detecting the density of the slurry in the slurry tank 11, the viscosity sensor 113 is used for detecting the viscosity of the slurry in the slurry tank 11, and when the density of the slurry in the tank is increased, water is supplemented through an automatic valve on a water supplementing pump and a water supplementing pipeline so as to maintain the stability of the density of the slurry in the tank. The viscosity sensor 113 monitors the viscosity of the slurry, and changes in the temperature, density, concentration, etc. of the slurry cause changes in the viscosity. The fluid characteristics of the slurry are kept consistent when the viscosity is stable, and the consistency of the catalyst coating product is finally ensured.

The flow meter 16 is used for metering the amount of the slurry conveyed to the coating device 2, the flow meter 16 is used for detecting the liquid level height of the slurry by extending into the slurry tank, the flow meter 16 can accurately meter the amount of the slurry conveyed to the coating cavity, and the coating valve (the slurry supply device 1 also comprises the coating valve, and when the volume of the slurry flowing through the flow meter 16 is within a preset first volume threshold value, the controller controls the coating valve to be closed) controls, so that the coating amount is kept constant every time, and finally the consistency of the catalyst coating product is ensured; and feeding is carried out through automatic valves on a feeding pump and a feeding pipeline so as to maintain the stability of the slurry capacity in the tank.

The slurry supply device 1 further comprises a delivery pump 12 and a pressure stabilizing valve 13, wherein the delivery pump 12 is used for delivering slurry in the slurry tank 11 to an upper coating cavity or a lower coating cavity through a connecting hose 17, the pressure stabilizing valve 13 is arranged at the tail end of an outlet pipeline of the delivery pump 12, the pressure stabilizing valve 13 is used for balancing delivery pressure pulses of the delivery pump 12, a layer of light ring polytetrafluoroethylene membrane is arranged inside the pressure stabilizing valve 13, and the membrane is connected with a valve core. One side of the membrane is slurry, and the other side of the membrane is compressed air for stabilizing pressure. When the pressure of the slurry in the pipeline rises, the pressure pulse pushes the diaphragm to open the valve core, and redundant pressure is released due to the expansion of the volume in the valve; conversely, when the slurry pressure decreases, the compressed air pushes the diaphragm to raise the slurry pressure back after the valve core is closed. The pressure stabilizing valve 13 can keep the working pressure in the coating cavity stable for a long time under the regulation effect.

The upper coating cavity and the lower coating cavity are both connected with a slurry tank 11, the automatic coating system has a coating state, when the automatic coating system is in the coating state, the upper coating cavity and the lower coating cavity are arranged in one-to-one correspondence, a space for accommodating a catalyst carrier is arranged between the upper coating cavity and the lower coating cavity, and the slurry tank 11 conveys slurry to the catalyst carrier through the upper coating cavity or the lower coating cavity; the lower coating cavity is fixedly arranged on the operating platform, and the upper coating cavity can move to the lower coating cavity along with the mechanical claw, so that the upper coating cavity and the lower coating cavity are arranged in a one-to-one correspondence manner.

The upper coating cavity comprises an upper coating table, referring to fig. 5, an upper cavity 211 for accommodating one end of the catalyst carrier is formed on the upper coating table, a slot with a downward opening is formed on the upper coating table to form the upper cavity 211 of the catalyst carrier, and the cross section of the slot can be circular, square or other shapes matched with the catalyst carrier; the inner wall of the upper cavity 211 is provided with an annular screen 212 and a first sealing ring 213 arranged below the screen 212, the first sealing ring is an inflatable sealing ring, the first sealing ring 213 is arranged along the outer side wall of the upper cavity 211 and is of a hollow structure, the first sealing ring 213 has a clamping state, when the first sealing ring is in the clamping state, a catalyst carrier can be clamped to limit the separation of the catalyst carrier, one end part of the catalyst carrier is arranged below the first sealing ring 213, the upper cavity 211 and the upper end part of the catalyst carrier form a space capable of containing slurry, the upper cavity 211 is communicated with the slurry tank 11 through a connecting hose 17, so that the slurry in the slurry tank 11 can enter the space, and the slurry entering direction refers to an arrow pointed by a in fig. 5.

The upper coating chamber further comprises a first coating valve 214, a material level switch 216 and a first air source control valve 215, when the catalyst carrier is fed into the coating chamber, compressed air is fed into a first sealing ring (the inlet direction of the compressed air is shown by an arrow b in fig. 5) through the first air source control valve 215, and the first sealing ring is expanded to firmly clamp the catalyst carrier and seal the edge of the carrier. When the first coating valve 214 is opened, the slurry is buffered in the space formed by the upper cavity 211 and the upper end of the catalyst carrier, and the coating valve is closed after the slurry is metered by the flow meter 16 and reaches a preset first volume threshold range. Because the slurry has viscosity and surface tension, the slurry floats above the screen (the screen is an annular net-shaped component with a plurality of filter holes, the screen is very important and plays a role in buffering, and the slurry can uniformly enter the pore channels of the catalyst carrier), then the vacuum suction valve 223 of the lower coating cavity is opened, the slurry is sucked into the catalyst carrier in vacuum, so that the slurry can be attached to the inner wall of the catalyst carrier, a preset coating process is realized, and the uniformity of the slurry in the height and the uniformity in the thickness of the pore channel coating in the catalyst carrier are optimized; the level switch 216 can prevent unexpected situations such as slurry overflow after a detection error of the flow meter 16.

The lower coating cavity comprises a lower coating platform, referring to fig. 6, a lower cavity 221 for accommodating the other end of the catalyst carrier is formed in the lower coating platform, a slot with an upward opening is formed in the lower coating platform to form the lower cavity 221 for accommodating one end of the catalyst carrier, the cross section of the slot can be circular, square or other shapes matched with the catalyst carrier, and a pipeline communicated with the slurry tank is arranged at the bottom of the slot; the outer side wall of the lower cavity 221 is provided with a second sealing ring 222 with a hollow structure, the second sealing ring 222 is an air inflation sealing ring, the second sealing ring 222 has a clamping state, and the first sealing ring 213 and the second sealing ring 222 are used for synchronously clamping a catalyst carrier when the catalyst carrier is arranged between the upper cavity 211 and the lower cavity 221. The lower cavity 221 and the lower end of the catalyst carrier form a space capable of containing slurry, the lower cavity 221 is communicated with the slurry tank 11 through the connecting hose 17, so that the slurry in the slurry tank 11 can enter the space, and the slurry entering direction refers to an arrow indicated by d in fig. 6.

The lower coating chamber further includes a second coating valve 224, a vacuum suction valve 223, and a second air source control valve 225, and when the catalyst carrier is fed into the lower coating chamber, compressed air is fed into a second sealing ring (the slurry feeding direction is shown by an arrow denoted by c in fig. 6) through the second air source control valve 225, and the second sealing ring is expanded to firmly clamp the catalyst carrier and seal the peripheral edge of the carrier. When the second coating valve 224 is opened, the vacuum suction valve 223 is closed, the slurry enters the lower coating cavity, the pressure of the slurry pipeline forces the slurry to flow through the interior of the carrier from bottom to top, and the slurry is metered by the flow meter 16 and reaches a preset first capacity threshold range, then the second coating valve 224 is closed, the slurry is firstly cached in a space formed by the lower cavity 221 and the lower end of the catalyst carrier, then the vacuum suction valve 223 of the lower coating cavity is opened, and the slurry is sucked into the catalyst carrier in a vacuum manner, so that the slurry can be attached to the inner wall of the catalyst carrier; if the slurry exceeds the first predetermined capacity threshold, the slurry in the lower coating chamber and carrier is vacuum sucked into the vacuum tank and excess slurry is discharged.

Depending on the viscosity of the different slurries, the density of the filter pores in the catalyst support or the coating ratio, the upper coating chamber or the lower coating chamber is chosen for coating, and generally the upper coating chamber and the lower coating chamber do not need to be operated simultaneously. For example, the viscosity of the slurry is high, and an upper coating cavity is selected for coating; and on the contrary, the viscosity of the slurry is low, or the mesh number of the carrier is high, and the coating effect is better when the lower coating cavity is selected for coating. The lower coating cavity is selected to have the advantages that the semi-proportional coating (semi-coating for short, namely, only partial inner wall is coated with slurry relative to the whole coating) or partial coating is facilitated, and the phenomenon of hole blocking after the coating surface is not uniform is avoided; in addition, the slurry with low viscosity is convenient to be uniformly coated in a carrier made of special materials, and the application range is wider.

The suck-back device 3 is used for sucking back the slurry in the lower coating cavity, and the suck-back device 3 comprises a vacuum tank 31 connected with the lower coating cavity, a vacuum pump 32 connected with the vacuum tank 31 and a vacuum sensor 33 used for measuring the vacuum degree of the vacuum tank. The vacuum pump is driven by a variable-frequency motor, and stable vacuum degree can be established and maintained by maintaining specific motor frequency, so that the change of the vacuum degree in the coating process is kept consistent.

The first weighing device 5 is used for measuring the original weight of the catalyst carrier to be coated with the slurry, the second weighing device 6 is used for weighing the once-coated catalyst carrier to obtain a first weight, and the weight of the slurry in the once-coated catalyst carrier is determined according to the difference value between the original weight of the catalyst carrier and the first weight; the weighing device further comprises a third weighing device 7, wherein the third weighing device 7 is used for weighing the secondarily coated catalyst carrier to obtain a second weight, and the weight of the slurry in the secondarily coated catalyst carrier is determined according to the difference value between the original weight of the catalyst carrier and the second weight. First weighing device, second weighing device and third weighing device all have multiple structural style, as long as can realize weighing can.

The transfer device 4 is used for transferring catalyst carriers to different coating chambers and weighing devices, in one embodiment of the present invention, the transfer device 4 includes a robot arm 41, a drag chain 42 disposed on the robot arm 41, a driving mechanism 43 for driving the drag chain 42 to move, and a plurality of mechanical claws 44, each mechanical claw 44 is connected with the drag chain 42 through a connecting piece, and the drag chain 42 moves to drive the mechanical claw 44 to move under the driving of the driving mechanism 43; one gripper 44 can be fixedly connected to one upper coating chamber so that the upper coating chamber can move with the gripper 44, and not all grippers 44 are provided with an upper coating chamber, and in one embodiment of the present invention, two grippers are respectively fixedly provided with one upper coating chamber; or only one gripper is fixedly provided with an upper coating chamber.

The transfer device 4 has various structural forms as long as it can grasp the catalyst carrier, and is not limited to the specific structural form described above.

In an embodiment of the present invention, the upper coating chamber includes a first upper coating chamber 24 and a second upper coating chamber 26, the lower coating chamber includes a first lower coating chamber 25 disposed opposite to the first upper coating chamber 24 for coating the slurry for the first time and a second lower coating chamber 27 disposed opposite to the second upper coating chamber 26 for coating the slurry for the second time, the drying device, the first weighing device 5, the first lower coating chamber 25, the second weighing device 6, the second lower coating chamber 27 and the third weighing device 7 are sequentially disposed side by side on the same horizontal support table, the drying device is a first station, the first weighing device 5 is a second station, the first lower coating chamber 25 is a third station, the second weighing device 6 is a fourth station, the second lower coating chamber 27 is a fifth station, and the third weighing device 7 is a sixth station. The automatic coating system comprises a first mechanical claw arranged above the drying device, a second mechanical claw arranged above the first weighing device 5, a third mechanical claw arranged above the first lower coating cavity 25, a fourth mechanical claw arranged above the second weighing device 6, a fifth mechanical claw arranged above the second lower coating cavity 27 and a sixth mechanical claw arranged above the third weighing device 7, wherein a first upper coating cavity 24 is fixedly arranged on the third mechanical claw, and a second upper coating cavity 26 is fixedly arranged on the fifth mechanical claw.

The transfer device 4 is used for grabbing the catalyst carrier to enable the catalyst carrier to sequentially pass through different stations such as preheating, using a drying device, pre-weighing (using a first weighing device), primary coating, primary weighing (using a second weighing device), secondary coating and secondary weighing (using a third weighing device) according to a coating sequence, and finally the whole catalyst coating process is completed.

The specific coating process is as follows:

step 1: placing the catalyst carrier to be coated in a preheating cavity 81 of a drying device 8, and starting a hot air blower 82 to dry moisture in the catalyst carrier;

step 2: the first mechanical claw grabs the catalyst carrier and moves to the first weighing device 1 for weighing to obtain the initial weight of the catalyst carrier, the first mechanical claw returns to the initial position, then the second mechanical claw grabs the weighed catalyst carrier and transfers the catalyst carrier to the first lower coating cavity 25, and the second mechanical claw returns to the initial position;

and step 3: after the first upper coating cavity 24 on the third mechanical claw moves to the position above the first lower coating cavity 25, the first lower coating cavity 25 clamps the upper end part of the catalyst carrier, and the first lower coating cavity 25 clamps the lower end part of the catalyst carrier;

and 4, step 4: starting the first upper coating cavity 24 or the first lower coating cavity 25 to coat the catalyst carrier for the first time with slurry, closing the coating cavity after the coating amount is within the preset first capacity threshold range, then moving the catalyst carrier coated for the first time to the second weighing device 6 by the third mechanical claw (returning the third mechanical claw to the initial position), and weighing the catalyst carrier coated for the first time to obtain the first weight of the catalyst carrier;

and 5: judging whether the first weight of the catalyst carrier after one coating is in a qualified range, and in the first case: if so, the weight of the catalyst carrier is qualified; in the second case: if the first weight of the catalyst carrier after the primary coating is less than the preset qualified weight and secondary coating is needed, performing step 6; in the third case: if the first weight of the catalyst carrier after primary coating is greater than the preset qualified weight, pumping the redundant slurry, and then performing step 8;

step 6: calculating a preset second capacity threshold range of the slurry required by secondary coating, and after the fourth manipulator grabs the catalyst carrier and moves to the second lower coating cavity 27, returning the fourth manipulator to the initial position, the catalyst carrier is in the second lower coating cavity 27, moving the fifth manipulator and the second upper coating cavity 26 to the second lower coating cavity 27, clamping the upper end part of the catalyst carrier by the second upper coating cavity 26, clamping the lower end part of the catalyst carrier by the second lower coating cavity 27, starting the second upper coating cavity 26 or the second lower coating cavity 27, and coating the slurry in the preset second capacity threshold range into the catalyst carrier;

after the slurry is coated, the coating cavity is closed, the fifth manipulator grabs the catalyst carrier after the secondary coating and moves to the third weighing device 6, the fifth manipulator and the second upper coating cavity 26 return to the initial position, and the third weighing device is used for weighing the catalyst carrier after the secondary coating to obtain the second weight of the catalyst carrier;

and 7: judging whether the second weight of the catalyst carrier subjected to secondary coating in the step 6 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, if the second weight is smaller than the preset qualified weight, sequentially performing a coating step and a weighing step until the weight of the catalyst carrier is within the qualified range, generally, preferably coating twice, because the slurry can be dried in a short time, the slurry characteristics can be influenced and the slurry is wasted by coating for multiple times, if the coating is only performed twice, the coated catalyst carrier can be judged to be unqualified in weight in the step, the deviation percentage of the unqualified weight is calculated, and the slurry required by secondary coating in the step 6 is adjusted according to a preset calculation formula;

step 8, starting a back suction device, discharging slurry exceeding a preset qualified range, and measuring the weight of the catalyst carrier after the slurry is discharged by using a third weighing device to obtain a third weight;

step 9, judging whether the third weight of the catalyst carrier after the slurry is discharged in the step 8 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, the weight of the catalyst carrier is unqualified, the deviation percentage of the unqualified weight is calculated, and the operation parameters of the back suction device in the step 8 are adjusted according to a preset calculation formula.

During the whole coating process, the catalyst carrier moves at different stations along with the manipulator.

Each gripper has an initial position and a working position, and the initial position is disposed adjacent to the working position.

The invention also provides a coating process based on the automatic catalyst slurry coating system, if two coating opportunities exist, the slurry coated twice enters the catalyst carrier through 2 different upper coating cavities respectively; or the slurry coated twice enters the catalyst carrier through 2 different lower coating cavities respectively; or the slurry coated for the first time firstly enters the catalyst carrier through the upper coating cavity, and the slurry coated for the second time enters the catalyst carrier through the lower coating cavity; or the slurry coated for the first time firstly enters the catalyst carrier through the lower coating cavity, and the slurry coated for the second time enters the catalyst carrier through the upper coating cavity. If the catalyst carrier reaches the qualified weight after the first coating, the second coating of the slurry is not needed. If two coats are required, i.e., in step 4 and step 6 above, the slurry can be passed through the upper coat chamber and the lower coat chamber, respectively, into the catalyst support.

The double coating process provided by the invention comprises the following steps, see fig. 8:

s1, setting a preset first capacity threshold range for the slurry to be coated, and setting a preset pass weight (expected weight to be achieved) and pass range (i.e., within a deviation range) for the catalyst support;

s3, feeding the slurry into a catalyst carrier for primary coating, and measuring the first weight of the catalyst carrier after the primary coating by a second weighing device;

s4, judging whether the first weight of the catalyst carrier after primary coating is in a preset qualified weight range, if not, executing a step S5; if so, the weight of the catalyst carrier is qualified, step S5 is omitted, and the catalyst carrier is conveyed to the next station;

s5, calculating to obtain a difference value between the qualified weight and the first weight, and if the difference value is zero, determining that the weight of the catalyst carrier is qualified; if the difference is positive, i.e. the first weight is lower than the qualified weight, go to step S6; if the difference is negative, i.e. the first weight is higher than the qualified weight, go to step S8;

s6, calculating a preset second capacity threshold range of slurry required by secondary coating, feeding the slurry with the preset capacity into the catalyst carrier for secondary coating, and measuring the weight of the catalyst carrier after the secondary coating by using a third weighing device to obtain a second weight;

s7, judging whether the second weight of the catalyst carrier after the secondary coating in the step S6 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, the weight of the coated catalyst carrier is unqualified, the deviation percentage of the unqualified weight is calculated, and the slurry required by secondary coating in the step S6 is adjusted according to a preset calculation formula; the purpose of adjusting the parameters is to make the next product reach the predetermined qualified weight range, and the unqualified product marked at the position is rejected in a subsequent device;

s8, starting a suck-back device, discharging the slurry exceeding the preset qualified range (the suck-back process is as follows: opening a vacuum suction valve, sucking the slurry in the lower coating cavity and the carrier into a vacuum tank in vacuum, and sucking back the slurry exceeding the preset first capacity threshold range for discharge), and measuring the weight of the catalyst carrier after the slurry is discharged by using a third weighing device to obtain a third weight;

s9, judging whether the third weight of the catalyst carrier after the slurry is discharged in the step S8 is within a preset qualified range, if so, determining that the weight of the coated catalyst carrier is qualified; if not, the weight of the catalyst carrier is unqualified, the deviation percentage of the unqualified weight is calculated, and the operation parameters of the back suction device in the step S8 are adjusted according to a preset calculation formula; the purpose of the parameter adjustment will be to bring the next product to a predetermined acceptable weight range. The defective products marked here will be rejected in subsequent devices.

The calculation mode is a method for calculating parameters such as preset coating pressure, flow, coating time, coating suction vacuum and the like according to the standard size, the standard first weight, the standard mesh value, the actual first weight, the actual second weight and the actual third weight of the carrier.

The coating process of the catalyst slurry automatic coating system provided by the invention selects an optimized coating mode and coating process according to the viscosity of different slurries or the mesh number or coating proportion of catalyst carriers so as to realize the uniformity and accuracy of the slurry in the catalyst carriers: for example, if the slurry has a high viscosity, or the number of the catalyst carriers is low (for example, 500 meshes or less), or the slurry is completely coated (the entire inner wall of the catalyst carrier is completely coated with the catalyst slurry), the coating method is most preferably adopted; if the viscosity of the slurry is larger (for example, the viscosity is more than 400 cp), the upper coating cavity is selected to be started, and the slurry enters the catalyst carrier from top to bottom through the upper coating cavity; if the number of the catalyst carrier meshes is small (for example, less than 500 meshes), or if the catalyst carrier needs to be coated in a full proportion, the coating method is adopted, and the uniformity and accuracy of the slurry in the catalyst carrier are higher than those of the lower coating method.

If the viscosity of the slurry is low, or the mesh number of the catalyst carrier is high, or partial area coating is needed, a lower coating mode is adopted, and the slurry enters the catalyst carrier from bottom to top through a lower coating cavity. If the viscosity of the slurry is low (for example, the viscosity is below 400 cp), the lower coating mode is adopted. If the catalyst support needs to be coated in regions even if the mesh number of the catalyst support is large (for example, 500 meshes or more), the slurry in the catalyst support is selected to have better uniformity and accuracy than the slurry in the catalyst support coated in the lower coating mode.

The upper coating mode and the lower coating mode have no mandatory selection standard, the upper coating mode or the lower coating mode is selected under the conditions of different catalyst slurry viscosities or catalyst carrier mesh numbers or coating proportions, and the deviation ranges of the coating weights are different, so that the uniformity and the accuracy of the slurry in the catalyst carrier can be effectively improved by selecting the proper coating mode.

Under the same environmental conditions, the same slurry (e.g., three-way catalyst TWC) was applied to the same catalyst support in the same volume, and prior to application, the average coating amounts were sampled and measured using the conventional process (using the single under-coat method) for the coating cans in winter and summer, respectively, as shown in table 1, the average coating amounts were sampled and measured using the conventional process (using the single over-coat method) for the coating cans in winter and summer, respectively, as shown in table 2, and the results of the tests using the coating process provided by the present invention, as shown in table 3, were determined as follows: ambient temperature: the indoor temperature of a coating workshop is 5 ℃ at the lowest in winter, 35 ℃ at the highest in summer, the solid content is 43%, the viscosity is 1489cp, the coating weight is 550g theoretically required, the qualified requirement of quality control of coating precision is not less than 2% of the coating weight, if the coating amount is too much, although the influence on the performance and quality of the catalyst is not great, the production cost is increased. The conventional process (using a single coating method) cannot perform a high-quality coating process for catalyst carriers such as DPF (diesel particulate trap) and GPF (gasoline particulate trap) and a zone coating process, and thus is not compared here.

TABLE 1 test results after coating the catalyst support with the slurry using a single under-coating method

Table 2 test results after coating the catalyst support with the slurry using the single coating method

Table 3 test results after coating catalyst support with slurry using the coating process provided by the present invention

As can be seen from tables 1, 2 and 3 above, by using a single upper coating method or a single lower coating method, defective products are liable to occur, and the traditional method can not adjust the key parameters of the slurry such as temperature, viscosity, solid content, conveying pressure pulsation and the like, so that the uniformity of the slurry properties cannot be ensured at different temperatures in different seasons, thereby affecting the final coating effect, wherein all experiments are carried out at the same environmental temperature, for example, the same temperature is 5 ℃ in winter and 35 ℃ in summer, the different characteristics of the slurry mean that the traditional process can not adjust the temperature, viscosity, solid content, conveying pressure pulsation and the like, the characteristics of the slurry can not meet the requirements, in the invention, the characteristics of the slurry can be adjusted, and the uniformity of the coating height of the slurry on the inner wall of the pore channel of the catalyst carrier is controlled through detection so as to reach the optimal state of the theoretical standard of the slurry.

The coating device and the coating process solve the problems that the traditional coating process is complex in operation process, needs a large amount of manual mold changing operation and is low in long-acting rate of coating mold changing time; the problems of uniformity and repeatability in the coating process are solved, the consistency of the catalyst product is enhanced, and strict quality management specifications of the automobile industry and the environmental protection industry are met; meanwhile, the physical property of the coating raw materials of the catalyst for the national six-year old is greatly changed, so that the requirement on regional coating is obviously increased, and the reliability of regional coating (half coating) can be greatly enhanced by the full-automatic coating process; the coating amount of each time is kept constant, and the consistency of the catalyst coated product is finally ensured; by setting different flow values of zone coating, the coating range of the zone coating can be accurately controlled, and the production consistency and repeatability of products are met.

The coating device provided by the invention integrates the upper coating cavity and the lower coating cavity, can be selected according to the characteristics of slurry to be coated, can be used for coating catalyst slurry on different catalyst carriers, has universality and can meet different requirements; through setting up temperature sensor, level sensor, density sensor and viscosity sensor, uniformity and the accuracy of catalyst thick liquids in can the effective control whole coating process, avoid the skew of temperature, viscosity, density and concentration to take place around the thick liquids in the whole coating process. The coating process can be selected according to the characteristics of the slurry to be coated, can finish coating the catalyst slurry in a short time, automatically correct process deviation, reduce material leakage and loss, improve production efficiency and is simple to operate.

The sizes and specifications of the carriers are different according to different vehicle types and engine characteristics, and meanwhile, even if the carriers with the same size and specification are used, the components and the characteristics of the used catalyst coating slurry are different due to different combustion working conditions of engines of various vehicles and enterprises. For catalyst production enterprises, the adjustment and the model change of the production line are realized when the different carriers and components are produced, and the coating device and the coating process are completely suitable for automatically coating carriers with various varieties and multiple characteristics and can meet the model change production of various catalysts; the equipment has a compact structure, is fully automatically operated, and can maximally utilize the energy production requirement of the equipment; the unique totally-enclosed design reduces the leakage and loss of materials; the coating process can automatically correct the deviation of the coating slurry, so that the setting of the coating parameters is simpler and more intuitive, and the quality risk of new product research and development is reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An automatic catalyst slurry coating system for coating catalyst slurry into catalyst carriers, characterized in that the coating system comprises a slurry supply device (1), one or more upper coating chambers, one or more lower coating chambers, a suck-back device (3) connected to the lower coating chambers, a transfer device (4) for transferring catalyst carriers, a first weighing device (5) for measuring the weight of catalyst carriers, a second weighing device (6) and a third weighing device (7);

the slurry supply device (1) comprises a slurry tank (11) and a flow meter (16), wherein the flow meter (16) is used for metering the volume of the slurry delivered from the slurry tank (11) to an upper coating cavity or a lower coating cavity;

the automatic coating system is characterized in that the upper coating cavity and the lower coating cavity are both connected with a slurry tank (11), the automatic coating system is in a coating state, when the automatic coating system is in the coating state, the upper coating cavity and the lower coating cavity are arranged in a one-to-one correspondence manner, a space for accommodating a catalyst carrier is arranged between the upper coating cavity and the lower coating cavity, and the slurry tank (11) conveys slurry to the catalyst carrier through the upper coating cavity or the lower coating cavity;

the first weighing device (5) and the second weighing device (6) are respectively arranged on two sides of a lower coating cavity, the first weighing device (5) is used for metering the original weight of the catalyst carrier to be coated with the slurry, and the second weighing device (6) is used for metering the weight of the catalyst carrier coated with the slurry for one time; the third weighing device (7) and the second weighing device (6) are arranged on two sides of the other lower coating cavity and are used for metering the weight of the catalyst carrier after the slurry is coated for the second time;

the suck-back device (3) is used for discharging slurry from the lower coating cavity.

2. The automatic catalyst slurry coating system according to claim 1, wherein the upper coating chamber comprises an upper coating table, an upper chamber (211) for accommodating one end of the catalyst carrier is formed in the upper coating table, an annular screen (212) and a first sealing ring (213) arranged below the screen (212) are arranged on the inner wall of the upper chamber (211), and the first sealing ring (213) is arranged along the outer side wall of the upper chamber (211);

the lower coating cavity comprises a lower coating table, a lower cavity (221) used for containing the other end of the catalyst carrier is formed in the lower coating table, a second sealing ring (222) of a hollow structure is arranged on the outer side wall of the lower cavity (221), and the first sealing ring (213) and the second sealing ring (222) are used for synchronously clamping the catalyst carrier when the catalyst carrier is arranged between the upper cavity (211) and the corresponding lower cavity (221).

3. The automatic catalyst slurry coating system according to claim 1, wherein the upper coating chamber comprises a first upper coating chamber (24) and a second upper coating chamber (26), the lower coating chamber comprises a first lower coating chamber (25) opposite to the first upper coating chamber (24) for coating the slurry once and a second lower coating chamber (27) opposite to the second upper coating chamber (26) for coating the slurry twice, and the first weighing device (5), the first lower coating chamber (25), the second weighing device (6), the second lower coating chamber (27) and the third weighing device (7) are sequentially arranged side by side.

4. The automatic catalyst slurry coating system according to claim 1, wherein a stirring device (116) is arranged in the slurry tank (11), a plurality of slurry feed inlets (112) and a plurality of feed back ports are arranged on the slurry tank (11), the feed inlets (112) are connected with a feed pump through a pipeline, the feed back ports are connected with a feed back pump (14) through a pipeline, and switching valve ports are fixedly arranged on the pipelines; the surface of thick liquids jar (11) is provided with presss from both sides jacket layer (114), form the holding cavity between jacket layer (114) and thick liquids jar (11), be provided with on jacket layer (114) and stretch into temperature sensor (115) in thick liquids jar (11).

5. The automatic catalyst slurry coating system according to claim 1, wherein a liquid level sensor (111), a density sensor and a viscosity sensor (113) are further arranged on the slurry tank (11), the liquid level sensor (111) is used for detecting the volume of the slurry in the slurry tank (11), the density sensor is used for detecting the density of the slurry in the slurry tank (11), and the viscosity sensor (113) is used for detecting the viscosity of the slurry in the slurry tank (11).

6. The automatic catalyst slurry coating system according to claim 1, further comprising a drying device (8) for heating a catalyst carrier to be coated with the slurry, wherein the drying device (8) has a preheating chamber (81) for accommodating the catalyst carrier and a hot air blower (82) for providing heat and blowing the heat to the preheating chamber (81).

7. The automatic catalyst slurry coating system according to claim 1, wherein the slurry supply device (1) further comprises a delivery pump (12) and a pressure maintaining valve (13), the delivery pump (12) is used for delivering the slurry in the slurry tank (11) to the upper coating cavity or the lower coating cavity through a connecting hose (17), and the pressure maintaining valve (13) is arranged at the tail end of an outlet pipeline of the delivery pump (12); the suck-back device (3) comprises a vacuum tank (31) connected with the lower coating cavity and a vacuum pump (32) connected with the vacuum tank (31);

the transfer device (4) comprises a mechanical arm (41), a drag chain (42) arranged on the mechanical arm (41), a driving mechanism (43) used for driving the drag chain (42) to move and a plurality of mechanical claws (44), wherein the drag chain (42) can drive the mechanical claws (44) to move, and one upper coating cavity (44) can be fixedly connected with one mechanical claw, so that the upper coating cavity can move along with the mechanical claws (44).

8. A coating process based on the catalyst slurry automatic coating system of any one of claims 1 to 7, characterized by comprising a double coating process, wherein the double coated slurry enters a catalyst carrier through 2 different upper coating cavities respectively; or the slurry coated twice enters the catalyst carrier through 2 different lower coating cavities respectively; or the slurry coated for the first time firstly enters the catalyst carrier through the upper coating cavity, and the slurry coated for the second time enters the catalyst carrier through the lower coating cavity; or the slurry coated for the first time firstly enters the catalyst carrier through the lower coating cavity, and the slurry coated for the second time enters the catalyst carrier through the upper coating cavity.

9. The coating process of the catalyst slurry automatic coating system according to claim 8, wherein the two-coating process comprises the steps of:

10. The coating process of the automatic catalyst slurry coating system according to claim 8, wherein an optimum coating method is selected according to the viscosity of different catalyst slurries or the mesh number or coating ratio of catalyst carriers,