Roller press and pre-classification regrind on-line detection self-circulation process method

Abstract

The application provides a kind of roller press and pre-classification return powder online detection self-circulation process method, classification machine return powder outlet is connected to two detection loops, wherein the first loop detects the fine powder rate in the classification machine return powder, the material in the second loop comes from the roller press, and the detection equipment in the first loop is also included in the second loop.The fine powder rate in the material out of the roller press is detected by the second loop through double-bucket lifting process when the material in the roller press comes from the return powder in the classification machine;The fine powder rate in the material out of the roller press is detected by the second loop through single-bucket lifting process when the material in the roller press comes from the mixture of return powder in the classification machine and new feeding.The application detects the fine powder content in the classification machine return powder or the fine powder content in the material out of the roller press in real time, and the detected material is returned to the grinding system for reuse in real time, ensuring the representativeness of sampling, improving the detection efficiency, quickly guiding system adjustment, avoiding safety operation hidden danger, and saving manpower and time resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material online detection, and more particularly to a roller press and pre-classification return powder online detection self-circulation process method. BACKGROUND

[0002] The roller press material bed grinding equipment is a high-efficiency and energy-saving crushing and grinding equipment, which is widely used in the fields of building materials, metallurgy, chemical industry, and mining. The content of finished products in the material processed by the roller press is a very key index for evaluating the performance of the roller press. Due to the large throughput of the roller press, the usual detection method is to take the materials discharged from the roller press at the left, middle and right positions at the bottom of the roller press equipment for manual screening detection. The representativeness of the sampling and the consistency of the detection method cannot be guaranteed, and the operating efficiency of the roller press after adjusting the system parameters cannot be quickly fed back.

[0003] The material processed by the roller press is dispersed and classified into coarse and fine particles by a V-shaped static powder classifier or a dynamic sorting integrated machine, etc. The coarse particles are returned to the roller press as return powder for regrinding, and the fine particles are semi-finished products or semi-finished products which enter subsequent fine dynamic powder sorting equipment or are directly collected into a ball mill for processing. If the return powder contains a large amount of fine particles, it will affect the grinding efficiency of the roller press. If the semi-finished products or semi-finished products contain a large amount of coarse particles, the processing efficiency of the next stage will be affected. The fine powder content in the return powder of the pre-classification equipment is a very key technical index for evaluating the pre-classification equipment. However, in actual operation, the return powder quantity is large, and manual detection of the fine powder content in the return powder of the entire equipment cross section has problems such as long time consumption, laborious sampling, limited operation, sampling representativeness, and detection material cannot be returned to the system for reuse, etc. This causes waste of human resources, time and other resources, and there are certain operation safety hazards. SUMMARY

[0004] The present application provides a roller press and pre-classification return powder online detection self-circulation process method, which is used to solve the problems of long time consumption, limited operation, and waste of human resources, time and other resources in the detection of fine powder rate in the return powder of the roller press and the classifier in the prior art.

[0005] The present application provides a roller press and pre-classification return powder online detection self-circulation process method, which includes a classifier return powder detection method and a roller press discharge material detection method.

[0006] The pre-classification return powder detection method is realized based on a first return circuit controlled by a control system. The first return circuit includes a classifier, a first metering device, a first single-way control valve and a screening device connected in sequence with the return powder outlet of the classifier. The fine powder outlet of the screening device is connected with a second metering device. The classifier return powder detection method is as follows.

[0007] Step 1, control the material discharged from the return powder outlet of the classifier to the first metering device;

[0008] Step 2, control the first metering device to weigh the received material, and transmit the first data T1 obtained by weighing to the control system;

[0009] Step 3, open the first single-pass control valve, so that the weighed material enters the screening device, the screening device screens the weighed material into first coarse powder and first fine powder, and the first fine powder enters the second metering device;

[0010] Step 4, when the control system detects that the screening device is empty, control the second metering device to weigh the first fine powder, and transmit the second data T2 obtained by weighing to the control system;

[0011] Step 5, according to the ratio of the second data T2 to the first data T1, calculate the content P1 of fine powder in the classifier return powder;

[0012] The roll mill material detection method is realized based on a second loop controlled by the control system, the second loop includes, in sequence, a roll mill connected with the classifier return powder outlet, the first metering device, the screening device and the second metering device; the roll mill material detection method is as follows:

[0013] S1, control the material discharged from the classifier return powder outlet to enter the roll mill for grinding, and the ground material enters the first metering device;

[0014] S2, control the first metering device to weigh the received material, and transmit the third data T3 obtained by weighing to the control system;

[0015] S3, open the first single-pass control valve, so that the weighed material enters the screening device, the screening device screens the weighed material into second coarse powder and second fine powder, and the second fine powder enters the second metering device;

[0016] S4, when the control system detects that the screening device is empty, control the second metering device to weigh the second fine powder, and transmit the fourth data T4 obtained by weighing to the control system;

[0017] S5, according to the ratio of the fourth data T4 to the third data T3, calculate the content P2 of fine powder in the roll mill return powder.

[0018] Optionally, the classifier is a V-shaped static classifier;

[0019] The air inlet side of the air inlet chamber of the V-shaped static classifier is communicated with a multi-flow adjusting connecting air pipe, which is in the same plane with the V-shaped static classifier and is located at the upper, middle and lower parts of the entire vertical section of the air inlet side; the multi-flow adjusting connecting air pipe comprises a multi-flow adjusting main air pipe located at the top and a plurality of multi-flow adjusting branch air pipes located below the multi-flow adjusting main air pipe, and the multi-flow adjusting main air pipe and the multi-flow adjusting branch air pipes are arranged side by side; the pipe diameter of the multi-flow adjusting main air pipe is larger than that of the multi-flow adjusting branch air pipes, and the multi-flow adjusting main air pipe is connected with the main air inlet of the air inlet chamber.

[0020] Optionally, the classifier powder return outlet is connected with a first material distribution control valve, and the first material distribution control valve is connected with the first metering device and the material stabilizing weighing bin respectively.

[0021] Optionally, the second metering device is sequentially connected with a second single-pass control valve, a first elevator and a classifier, and the weighed fine powder is returned to the classifier through the first elevator.

[0022] The coarse powder outlet of the screening device is connected with the material stabilizing weighing bin, and the screened coarse powder is discharged into the material stabilizing weighing bin.

[0023] Optionally, when the fine powder rate in the classifier powder return is not needed to be detected, the classifier powder return is all discharged into the material stabilizing weighing bin.

[0024] Optionally, the roller press discharge outlet is sequentially connected with the first elevator and the classifier.

[0025] Optionally,

[0026] When the second material distribution control valve is arranged between the roller press discharge outlet and the feeding inlet of the first elevator, the second material distribution control valve is connected with a second elevator respectively, and is used for discharging the roller press powder return to the first elevator and the second elevator; the second elevator is connected with the first metering device.

[0027] When the third material distribution control valve is arranged between the feeding inlet of the first elevator and the feeding inlet of the classifier, the roller press discharge outlet is sequentially connected with the first elevator, the first pipeline of the third material distribution control valve and the classifier; the second pipeline of the third material distribution control valve is connected with the first metering device.

[0028] Optionally, the feeding inlet of the first elevator is connected with a first feeding device.

[0029] Optionally,

[0030] The feeding inlet of the first elevator is connected with a first feeding device.

[0031] Optionally, when the fine powder rate of the material of the roller press does not need to be detected, the material discharged from the roller press is controlled to enter the classifier entirely.

[0032] Optionally, the back powder detection of the classifier and the material detection of the roller press are not performed at the same time.

[0033] The present application has at least the following beneficial effects:

[0034] The present application provides a roller press and pre-classification back powder online detection self-circulation process method, which comprises two detection loops controlled by a control system. The first loop detects the fine powder rate in the back powder of the classifier, and the second loop detects the fine powder rate in the material discharged from the roller press. The material in the roller press comes from the back powder in the classifier, and the second loop also comprises the detection device in the first loop. The present application can be used to detect the fine powder content in the back powder of the classifier or the fine powder content in the material discharged from the roller press in real time. The detected material is returned to the grinding system for reuse in real time, the representativeness of sampling is guaranteed, the detection efficiency is improved, the system adjustment is quickly guided, certain safety operation risks are avoided, and manpower, time and resources are saved. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0036] Figure 1 is a schematic diagram of a roller press and pre-classification back powder online detection self-circulation system of the present application;

[0037] Figure 2 is a schematic diagram of a roller press and pre-classification back powder online detection self-circulation system of the present application;

[0038] Figure 3 is a schematic diagram of a V-shaped static classifier of the present application.

[0039] 1, roller press; 2, first elevator; 3, third material distribution control valve; 4, classifier; 41, multi-flow adjustment main air pipe; 42, feeding port; 43, classifier air outlet; 44, classification plate; 45, guide plate; 46, multi-flow adjustment branch air pipe; 47, powder return outlet; 5, first material distribution control valve; 6, first metering device; 7, first single-pass control valve; 8, screening device; 9, second metering device; 10, second single-pass control valve; 11, material stabilizing weighing bin; 12, second feeding device; 13, first feeding device; 14, second material distribution control valve; 15, second elevator; 16, third single-pass control valve. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] The present application provides a roller press and a pre-classification powder return online detection self-circulation process method, including a pre-classification powder return online detection method and a roller press material detection method;

[0042] The pre-classification powder return online detection method is realized based on a first loop controlled by a control system, and the first loop includes a classifier 4 and a first metering device 6, a first single-pass control valve 7 and a screening device 8 connected in sequence with a powder return outlet 47 of the classifier 4; a fine powder outlet of the screening device 8 is connected with a second metering device 9; and the pre-classification powder return online detection method is as follows:

[0043] Step 1, control the material discharged from the powder return outlet 47 of the classifier 4 to the first metering device 6;

[0044] Step 2, control the first metering device 6 to weigh the received material and transmit first data T1 obtained by weighing to the control system;

[0045] Step 3, open the first single-pass control valve 7 to make the weighed material enter the screening device 8, and the screening device 8 screens the weighed material into first coarse powder and first fine powder, and makes the first fine powder enter the second metering device 9;

[0046] Step 4, when the control system detects that the screening device 8 is empty, control the second metering device 9 to weigh the first fine powder and transmit second data T2 obtained by weighing to the control system;

[0047] Step 5, calculate the fine powder content P1 in the classifier 4 return powder according to the ratio of the second data T2 and the first data T1;

[0048] The roll press material detection method is realized based on a second loop of the control system, and the second loop comprises, in sequence, the roll press 1, the first metering device 6, the screening device 8 and the second metering device 9 connected with the classifier 4 return powder outlet 47; the roll press 1 material detection method is as follows:

[0049] S1, control the material discharged from the classifier 4 return powder outlet 47 or the mixed material of the material discharged from the classifier 4 return powder outlet and the new feed to enter the roll press 1 for grinding, and the ground material enters the first metering device 6;

[0050] S2, control the first metering device 6 to weigh the material from the roll press 1, and transmit the third data T3 obtained by weighing to the control system;

[0051] S3, open the first single-way control valve 7, so that the weighed material enters the screening device 8, and the screening device 8 screens the weighed material into second coarse powder and second fine powder, and the second fine powder enters the second metering device 9;

[0052] S4, when the control system detects that the screening device 8 is empty, control the second metering device 9 to weigh the second fine powder, and transmit the fourth data T4 obtained by weighing to the control system;

[0053] S5, calculate the fine powder content P2 in the roll press return powder according to the ratio of the fourth data T4 and the third data T3.

[0054] Specifically, the pre-classification return powder online detection method is realized based on a first loop of the control system, and the specific process is as follows:

[0055] Step 1, the control system controls the classifier 4 return powder outlet 47 to discharge a certain amount of material to the first metering device 6, at this time the first single-way control valve 7 is closed to prevent the material in the first metering device 6 from being discharged to other devices before being weighed.

[0056] Step 2, when the return material outlet no longer discharges material to the first metering device 6, control the first metering device 6 to weigh the material in the first metering device 6, and the data obtained by weighing is the first data T1, and the first metering device 6 transmits the first data T1 to the control system for storage.

[0057] Step 3, after receiving the first data T1, the control system controls the first single-pass control valve 7 to open, so that the weighed material enters the screening device 8, and then controls the screening device 8 to screen the weighed material into first coarse powder and first fine powder, and the first fine powder enters the second metering device 9. When the control system detects that the first metering device 6 is empty, the first single-pass control valve 7 is closed after the first metering device 6 is closed.

[0058] Step 4, when the control system detects that the screening device 8 is empty, it means that the material in the screening device 8 has been completely screened, and the screening device 8 stops working. At this time, the second metering device 9 is controlled to weigh the first fine powder, and the weight data of the first fine powder, i.e. the second data T2, is obtained, and the second metering device 9 is controlled to transmit the second data T2 to the control system.

[0059] Step 5, the control system calculates the fine powder content P1 in the classifier 4 return powder according to the pre-stored fine powder content P1 calculation formula: P1 = (T2 / T1) x 100.

[0060] The roller press 1 material detection method is realized based on the second loop controlled by the control system, and the specific process is as follows:

[0061] S1, keep the second material control valve 5 from feeding the first metering device 6, and control the return powder from the classifier 4 outlet 47 to enter the roller press for grinding. The ground material enters the first metering device 6;

[0062] S2, the control system controls the first metering device 6 to weigh the material coming out of the roller press 1, obtains the third data T3, and transmits the third data T3 to the control system for storage.

[0063] S3, after the first metering device 6 is weighed, the first single-pass control valve 7 is opened, so that the weighed material enters the screening device 8 for screening, and the second fine powder and the second coarse powder are obtained after screening.

[0064] S4, control the second fine powder to enter the second metering device 9 for weighing, and obtain the fourth data T4;

[0065] S5, the control system calculates the fine powder content P2 in the material of the roller press 1 according to the pre-stored fine powder content P2 calculation formula: P2 = (T4 / T3) x 100. The production personnel can judge the grinding efficiency of the roller press 1 according to the value of the fine powder content P2.

[0066] In one possible implementation, the classifier 4 is a V-type static classifier.

[0067] The air inlet side of the air inlet chamber of the V-shaped static classifier 4 is connected with a multi-flow adjusting connecting air pipe, which is in the same plane as the V-shaped static classifier 4 and is located in the upper, middle and lower parts of the entire vertical section of the air inlet side; the multi-flow adjusting connecting air pipe includes a multi-flow adjusting main air pipe 41 located at the top and a plurality of multi-flow adjusting branch air pipes 46 located below the multi-flow adjusting main air pipe 41, and the multi-flow adjusting main air pipe 41 and the multi-flow adjusting branch air pipes 46 are arranged side by side; the pipe diameter of the multi-flow adjusting main air pipe 41 is larger than that of the multi-flow adjusting branch air pipes 46, and the multi-flow adjusting main air pipe 41 is connected with the main air inlet of the air inlet chamber.

[0068] Specifically, the classifier 4 in the present application is a V-shaped static classifier, and the feeding port 42 is located at the top of the intersection of the V-shaped structure formed by the air inlet chamber and the air outlet chamber, and the material is fed into the classifier 4 from the feeding port 42. After the material enters the air inlet chamber, it is affected by the airflow and begins to disperse. A plurality of stepwise inclined guide plates 45 are arranged in the air inlet chamber, which helps the material to be uniformly distributed and preliminarily classified in the air inlet chamber. The material enters the air outlet chamber along with the airflow, and a plurality of stepwise inclined classification plates 44 are arranged in the air outlet chamber, which further classifies the material according to the size and weight of the particles. Larger material particles will slide downward along the classification plates 44 due to their larger weight and size, and finally be discharged through the bottom return powder outlet 47. Smaller material particles are discharged through the gaps between the classification plates 44 and the air outlet of the classifier 4, and the fine powder required is collected.

[0069] The multi-flow adjusting connecting air pipe is in the same plane as the static classifier 4 and is located in the upper, middle and lower parts of the entire vertical section of the air inlet side, so that the static classifier 4 can realize uniform air inlet in the vertical plane and avoid the air volume being concentrated at the top of the static classifier 4. The pipe diameter of the multi-flow adjusting main air pipe 41 located at the top of the multi-flow adjusting connecting air pipe is larger than that of the multi-flow adjusting branch air pipes 46, and the multi-flow adjusting main air pipe 41 serves as the main air inlet channel of the air inlet chamber and needs to ensure sufficient airflow strength to drive the movement and dispersion of the material in the classifier 4. The larger pipe diameter can reduce the resistance of the airflow during transmission and ensure that the main airflow can smoothly and efficiently enter the air inlet chamber.

[0070] In a possible implementation, the classifier 4 return powder outlet 47 is connected with a first material distribution control valve 5, and the first material distribution control valve 5 is connected with the first metering device 6 and the material stabilizing weighing bin 11, respectively.

[0071] Specifically, the first material distribution control valve 5 connected with the classifier 4 back powder outlet 47 divides the material discharged from the back powder outlet 47 into different pipelines. When the control system needs to detect the fine powder rate in the classifier 4 back powder, the control system controls the first material distribution control valve 5 to discharge a certain amount of material in the first pipeline into the first metering device 6. The remaining back powder is discharged into the material stabilizing and weighing bin 11 through the second pipeline of the first material distribution control valve 5, and then enters the roller press 1 for grinding. A third single-way control valve 16 is arranged on the pipeline between the material stabilizing and weighing bin 11 and the roller press 1 to control whether the material in the material stabilizing and weighing bin 11 can enter the roller press 1. The material stabilizing and weighing bin 11 buffers the material discharged from the back powder outlet 47. If there is no buffering, a large amount of back powder directly enters the roller press 1, which may cause part of the material to be discharged from the roller press 1 without being ground.

[0072] In a possible implementation, the second metering device 9 is sequentially connected with the second single-way control valve 10, the first elevator 2 and the classifier 4, and the weighed fine powder is returned to the classifier 4 through the first elevator 2;

[0073] The coarse powder outlet of the screening device 8 is connected with the material stabilizing and weighing bin 11, and the screening device 8 discharges the screened coarse powder into the material stabilizing and weighing bin 11.

[0074] Specifically, the second metering device 9 is controlled to open and close through the second single-way control valve 10. When the second single-way control valve 10 is opened, the material in the second metering device 9 can be discharged from the second metering device 9. The material in the second metering device 9 is fine powder, which is discharged into the first elevator 2. When the control system detects that the second metering device 9 is empty, the second single-way control valve 10 after the second metering device 9 is closed. The first elevator 2 lifts the fine powder to the feeding port 42 of the classifier 4, and then feeds the fine powder into the classifier 4 for re-sorting.

[0075] The coarse powder outlet of the screening device 8 is connected with the material stabilizing and weighing bin 11, and the screening device 8 discharges the screened coarse powder into the material stabilizing and weighing bin 11, and then the coarse powder enters the roller press 1 for re-grinding.

[0076] In a possible implementation, when the fine powder rate in the classifier 4 back powder does not need to be detected, all the classifier 4 back powder is discharged into the material stabilizing and weighing bin 11.

[0077] Specifically, when the fine powder rate in the classifier 4 back powder does not need to be detected, the control system controls the first pipeline of the first material distribution control valve 5 to be closed, and all the classifier 4 back powder enters the material stabilizing and weighing bin 11, and then enters the roller press 1 for grinding.

[0078] In a possible implementation, the roller press 1 discharge port is sequentially connected to the first elevator 2 and the classifier 4 inlet.

[0079] Specifically, the material discharged from the roller press 1 is re-entered into the classifier 4 through the first elevator 2 for sorting.

[0080] In a possible implementation, when the second material distribution control valve 14 is arranged between the roller press discharge port and the first elevator inlet, the second material distribution control valve 14 is connected to the first elevator 2 and the second elevator 15 respectively, for discharging the powder from the roller press 1 to the first elevator 2 and the second elevator 15; the second elevator 15 is connected to the first metering device 6.

[0081] When the third material distribution control valve 3 is arranged between the first elevator 2 inlet and the classifier 4 inlet, the roller press 1 discharge port is sequentially connected to the first elevator 2, the first pipeline of the third material distribution control valve 3 and the classifier 4; the second pipeline of the third material distribution control valve 3 is connected to the first metering device 6.

[0082] Specifically, the roller press 1 discharge port is connected to the second material distribution control valve 14. The first pipeline of the second material distribution control valve 14 is connected to the first elevator 2, so that the ground material is directly discharged into the first elevator 2 and re-enters the classifier 4 through the first elevator 2 for sorting. The second pipeline of the second material distribution control valve 14 is connected to the second elevator 15, and the second elevator 15 is connected to the first metering device 6. The second pipeline of the second material distribution control valve 14 sends the material discharged from the roller press 1 to the first metering device 6.

[0083] The third material distribution control valve 3 is arranged between the first elevator 2 inlet and the classifier 4 inlet. The material discharged from the roller press 1 enters the first elevator 2. The material entering the first elevator 2 enters the classifier 4 through the first pipeline of the third material distribution control valve 3 for sorting. When the content of fine powder in the material discharged from the roller press 1 needs to be detected, the material entering the first elevator 2 from the roller press 1 enters the first metering device 6 through the second pipeline of the third material distribution control valve 3.

[0084] In a possible implementation, the first elevator 2 inlet is connected to the first feeding device 13.

[0085] Specifically, the first elevator 2 inlet is connected to the first feeding device 13. If the raw material entering the classifier 4 for sorting does not need to be ground first, the raw material is directly fed into the first elevator 2 inlet through the first feeding device 13 and is sent into the classifier 4 through the first elevator 2 for sorting.

[0086] In a possible implementation, the second feeding device 12 is connected to the inlet pipe of the stable material weighing bin 11.

[0087] Specifically, when the raw material needs to be ground before entering the classifier 4, the raw material is first fed into the stable material weighing bin 11 by the second feeding device 12, and then enters the roller press 1 from the stable material weighing bin 11 for grinding.

[0088] In a possible implementation, the pre-classification return powder online detection and the roller press 1 material detection are performed at different times.

[0089] Specifically, when the fine powder content in the classifier 4 return powder is detected, the fine powder content of the roller press 1 material is not detected; when the fine powder content of the roller press 1 material is detected, the fine powder content in the classifier 4 return powder is not detected.

[0090] The present application has the following advantages and beneficial effects:

[0091] 1. The present application can realize real-time detection of the fine powder content of the classifier 4 return powder and the roller press 1 material, and the detected material can be returned to the grinding system in real time for reuse, which can ensure the representativeness of sampling and improve the detection efficiency and material reuse rate.

[0092] 2. The detection result of the present application is fed back in real time through the control system, which quickly guides the adjustment of the system equipment and parameters.

[0093] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the present application.

[0094] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A self-circulating process for online detection of pre-graded powder return, characterized in that, This includes methods for detecting powder return from classifiers and methods for detecting material output from roller presses; The classifier powder return detection method is based on a first loop controlled by a control system. The first loop includes: a classifier and a first metering device, a first single-pass control valve, and a sieving device sequentially connected to the powder return outlet of the classifier; the fine powder outlet of the sieving device is connected to a second metering device; the classifier powder return detection method is as follows: Step 1: Control the discharge of material from the return powder outlet of the classifier to the first metering device; Step 2: Control the first metering device to weigh the received material and transmit the first data T1 obtained from the weighing to the control system; Step 3: Open the first single-pass control valve to allow the weighed material to enter the screening device. The screening device will screen the weighed material into a first coarse powder and a first fine powder, and allow the first fine powder to enter the second metering device. Step 4: When the control system detects that the screening device is unloaded, it controls the second metering device to weigh the first fine powder and transmits the second data T2 obtained from the weighing to the control system. Step 5: Calculate the fine powder content P1 in the returned powder from the classifier based on the ratio of the second data T2 to the first data T1; The material detection method for the roller press is based on a second loop controlled by the control system. The second loop includes: a roller press, a first metering device, a screening device, and a second metering device, all sequentially connected to the return powder outlet of the classifier. The material detection method for the roller press is as follows: S1. Control the material discharged from the return powder outlet of the classifier or the mixture of the material discharged from the return powder outlet of the classifier and the newly fed material to enter the roller press for grinding, and the ground material enters the first metering device. S2. Control the first metering device to weigh the received material and transmit the third data T3 obtained from the weighing to the control system; S3. Open the first single-pass control valve to allow the weighed material to enter the screening device. The screening device screens the weighed material into a second coarse powder and a second fine powder, and allows the second fine powder to enter the second metering device. S4. When the control system detects that the screening device is unloaded, it controls the second metering device to weigh the second fine powder and transmits the fourth data T4 obtained from the weighing to the control system. S5. Calculate the fine powder content P2 in the returned powder from the roller press based on the ratio of the fourth data T4 to the third data T3.

2. The self-circulating process method for online detection of pre-graded powder return as described in claim 1, characterized in that, The classifier is a V-type static classifier; The V-type static classifier has a multi-flow regulating connecting duct connected to the air inlet side of its air inlet chamber. The multi-flow regulating connecting duct is on the same plane as the V-type static classifier and is located at the upper, middle, and lower parts of the entire vertical section of the air inlet side. The multi-flow regulating connecting duct includes a main multi-flow regulating duct at the top and multiple branch multi-flow regulating ducts below the main multi-flow regulating duct. The main multi-flow regulating duct and the branch multi-flow regulating ducts are arranged side by side. The diameter of the main multi-flow regulating duct is larger than the diameter of the branch multi-flow regulating ducts, and the main multi-flow regulating duct is connected to the main air inlet of the air inlet chamber.

3. The self-circulating process method for online detection of pre-graded powder return as described in claim 1, characterized in that, The return powder outlet of the classifier is connected to a first material distribution control valve, which is connected to the first metering device and the material stabilizing weighing bin.

4. The roller press and pre-grading powder return online detection self-circulation process method according to claim 3, characterized in that, The second metering device is connected in sequence to the second single-way control valve, the first elevator, and the classifier. The weighed fine powder is returned to the classifier via the first elevator. The coarse powder outlet of the screening device is connected to the stable material weighing bin, and the screening device discharges the screened coarse powder into the stable material weighing bin.

5. The roller press and pre-grading powder return online detection self-circulation process method according to claim 4, characterized in that, When it is not necessary to detect the fine powder ratio in the returned powder from the classifier, all the returned powder from the classifier is discharged into the stable material weighing bin.

6. The self-circulating process method for online detection of pre-graded powder return as described in claim 4, characterized in that, The discharge port of the roller press is sequentially connected to the first elevator and the classifier.

7. The self-circulating process method for online detection of pre-graded powder return as described in claim 6, characterized in that, When a second material distribution control valve is installed between the discharge port of the roller press and the inlet of the first elevator, the second material distribution control valve is connected to the first elevator and the second elevator respectively, and is used to discharge the returned powder from the roller press to the first elevator and the second elevator; the second elevator is connected to the first metering device; When a third material distribution control valve is installed between the feed inlet of the first elevator and the feed inlet of the classifier, the discharge port of the roller press is sequentially connected to the first elevator, the first pipeline of the third material distribution control valve, and the classifier; the second pipeline of the third material distribution control valve is connected to the first metering device.

8. The roller press and pre-grading powder return online detection self-circulation process method according to claim 6, characterized in that, The feed inlet of the first elevator is connected to the first feeding device.

9. The roller press and pre-grading powder return online detection self-circulation process method according to claim 7, characterized in that, A second feeding device is connected to the inlet pipe of the material stabilizing weighing bin.

10. The self-circulating process method for online detection of pre-graded powder return during roller press and pre-classification as described in claim 1 or 7, characterized in that, When it is not necessary to detect the fine powder content of the material from the roller press, all the material discharged from the roller press is controlled to enter the classifier.

11. The roller press and pre-grading powder return online detection self-circulation process method according to claim 1, characterized in that, The powder return detection of the classifier and the material detection of the output roller press are not performed simultaneously.

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