Method, device, electronic equipment and dust removal system for checking abnormal particle concentration

Abstract

The present invention provides a method, device, electronic equipment and dust removal system for checking abnormal particle concentration, which relates to the field of steelmaking dust removal. The dust removal system includes an analysis device, a bag dust collector and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device, and the bag dust collector includes multiple chambers and intermediate air ducts. The analysis device can use the monitoring device to collect all particle concentrations during the cleaning cycle to analyze the average particle concentration corresponding to the cleaning period of each chamber. After calculating the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle and the cross-cycle concentration change value corresponding to each chamber, a troubleshooting prompt can be generated. The troubleshooting prompt can prompt maintenance personnel to check the chambers and / or factors to be checked. Therefore, the present invention can achieve targeted troubleshooting without manual carpet-style troubleshooting, saving troubleshooting time.

Description

Technical Field

[0001] The present invention relates to the field of steelmaking dust removal, and in particular to a method, device, electronic equipment and dust removal system for troubleshooting abnormal particle concentration. Background Art

[0002] In the steelmaking industry, dust removal is a key environmental protection measure used to control dust emissions, protect worker health, and prevent air pollution. For example, in the converter area of a steel mill, bag dust removal technology is often used in the hot metal pouring station dust removal system, hot metal (desulfurization) pretreatment dust removal system, refining dust removal system, converter secondary dust removal system, and converter tertiary dust removal system.

[0003] Each dust collection system in the converter operating area contains numerous dust collector chambers, potentially up to several thousand. The converter's secondary dust collection system, in particular, has 18 large chambers and 36 small chambers, housing 6,480 dust collection bags. Elevated dust particle concentrations could be due to a combination of factors: a damaged or detached bag, cracked welds in the intermediate air duct, a loose poppet valve seal, a faulty poppet valve cylinder, or a faulty poppet valve solenoid. However, due to the large number of chambers, manually locating the offending chamber is extremely time-consuming.

[0004] Therefore, when the concentration of dust particles in the exhaust gas from the dust collector increases abnormally, how to quickly locate the abnormal chamber is an urgent problem that needs to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, device, electronic equipment and dust removal system for checking abnormal particle concentration, so that when the dust particle concentration in the dust collector exhaust gas increases abnormally, a checking prompt is generated based on the average particle concentration corresponding to the cleaning period of each chamber, thereby realizing targeted checking.

[0006] The embodiments of the present invention can be implemented as follows:

[0007] In a first aspect, the present invention provides a method for troubleshooting abnormal particulate matter concentration, which is applied to an analysis device in a dust removal system, wherein the dust removal system also includes a bag dust collector and a monitoring device installed in an exhaust duct of the bag dust collector; the monitoring device is in communication with the analysis device, and the bag dust collector includes multiple chambers and an intermediate air duct. The method comprises:

[0008] During each cleaning cycle of the bag filter, concentration data collected by the monitoring device during the cleaning cycle is obtained; the concentration data includes particle concentrations at several different collection moments;

[0009] Based on the concentration data, respectively calculating the average particulate matter concentration corresponding to the cleaning period of each chamber in the cleaning cycle;

[0010] For each cleaning period in the current cleaning cycle, calculate the difference between the average particle concentration corresponding to the cleaning period and the average particle concentration corresponding to the previous cleaning period adjacent to the cleaning period, and obtain the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle;

[0011] For each chamber, calculate the difference between the average particle concentration corresponding to the cleaning period of the chamber in the current cleaning cycle and the average particle concentration corresponding to the cleaning period of the chamber in the previous cleaning cycle, and obtain the cross-cycle concentration change value corresponding to each chamber in the current cleaning cycle;

[0012] Based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber, an investigation prompt is generated. The investigation prompt is used to prompt maintenance personnel to check the chambers and factors to be checked.

[0013] In a second aspect, the present invention further provides a device for checking abnormal particle concentration, which is applied to an analysis device in a dust removal system, wherein the dust removal system further includes a bag dust collector and a monitoring device installed in an exhaust duct of the bag dust collector; the monitoring device is in communication with the analysis device, and the bag dust collector includes multiple chambers and an intermediate air duct; the device includes:

[0014] A data acquisition module is used to acquire concentration data collected by the monitoring device during each cleaning cycle of the bag filter; the concentration data includes the concentration of particulate matter at several different collection moments;

[0015] a calculation module, which calculates, based on the concentration data, an average particulate matter concentration corresponding to a cleaning period of each chamber in the cleaning cycle;

[0016] The calculation module is further configured to calculate, for each cleaning period in the current cleaning cycle, a difference between an average particle concentration corresponding to the cleaning period and an average particle concentration corresponding to a previous cleaning period adjacent to the cleaning period, to obtain an inter-period concentration change value corresponding to each cleaning period in the current cleaning cycle;

[0017] The calculation module is further configured to calculate, for each chamber, a difference between an average particle concentration corresponding to a cleaning period of the chamber in a current cleaning cycle and an average particle concentration corresponding to a cleaning period of the chamber in a previous cleaning cycle, to obtain an inter-cycle concentration change value corresponding to each chamber in the current cleaning cycle;

[0018] The prompt module is used to generate an inspection prompt based on the cross-time period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber. The inspection prompt is used to prompt maintenance personnel to check the chambers and factors to be checked.

[0019] In a third aspect, the present invention further provides an electronic device comprising: a memory and a processor, wherein the memory stores a software program, and when the electronic device is running, the processor executes the software program to implement the method for troubleshooting abnormal particulate matter concentration as described in the first aspect.

[0020] In a fourth aspect, the present invention further provides a dust removal system, comprising an analysis device, a bag dust collector, and a monitoring device installed in an exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device;

[0021] The monitoring device is used to collect the particle concentration of the gas discharged from the exhaust pipe according to a preset collection frequency during the operation of the bag filter, and send the collected particle concentration to the analysis device in real time for storage;

[0022] The analysis device is used to analyze the concentration data of each cleaning cycle of the bag filter according to the method for troubleshooting abnormal particle concentration described in the first aspect.

[0023] Compared with the prior art, the embodiments of the present invention provide a method, device, electronic equipment and dust removal system for checking abnormal particle concentration. The dust removal system includes an analysis device, a bag dust collector and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device, and the bag dust collector includes multiple chambers and intermediate air ducts. The analysis device can use the monitoring device to collect all particle concentrations during the cleaning cycle to analyze the average particle concentration corresponding to the cleaning period of each chamber. After calculating the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle and the cross-cycle concentration change value corresponding to each chamber, a troubleshooting prompt can be generated. The troubleshooting prompt can prompt maintenance personnel to check the chambers and / or factors to be checked. Therefore, the present invention can achieve targeted troubleshooting without the need for manual carpet-style troubleshooting, saving troubleshooting time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic diagram of the relationship between the working cycle and the cleaning cycle of a bag dust collector provided in an embodiment of the present invention.

[0026] Figure 2 A flow chart of a method for troubleshooting abnormal particulate matter concentration provided by an embodiment of the present invention.

[0027] Figure 3 A schematic diagram of the cleaning period for each chamber within a cleaning cycle provided in an embodiment of the present invention.

[0028] Figure 4 This is one of the example diagrams of the concentration change trend diagram within a cleaning cycle provided by an embodiment of the present invention.

[0029] Figure 5 This is the second example of a concentration change trend diagram within a cleaning cycle provided by an embodiment of the present invention.

[0030] Figure 6 This is the third example diagram of a concentration change trend diagram within a cleaning cycle provided by an embodiment of the present invention.

[0031] Figure 7 A continuous concentration change trend graph provided by an embodiment of the present invention.

[0032] Figure 8 A schematic diagram of the calculation principle of a concentration change value across a cycle and a concentration change value across time periods provided in an embodiment of the present invention.

[0033] Figure 9 A schematic structural diagram of a device for detecting abnormal particle concentration provided by an embodiment of the present invention.

[0034] Figure 10 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0038] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0039] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0040] Here, we first introduce the keywords or key terms involved in the present invention:

[0041] 1. Dust removal at the molten iron pouring station: When molten iron from a blast furnace is poured into a torpedo car or a ladle, a large amount of smoke and dust (including FeO, SiO2, etc.) is generated when the high-temperature molten iron comes into contact with the air, which requires dust removal.

[0042] 2. Dust removal during molten iron (desulfurization) pretreatment: When desulfurizers (such as magnesium powder, CaO) are sprayed into molten iron, the violent reaction will produce high-concentration, highly corrosive smoke (containing S, Ca, Mg, etc.), which requires dust removal.

[0043] 3. Secondary dust removal of converter: When adding scrap steel, tapping steel and splashing slag to protect the converter, smoke and dust (including FeO, CaO, CO, etc.) will be emitted, which requires dust removal.

[0044] 4. Converter tertiary dust removal: Dust removal is performed on ultrafine dust (below PM2.5) that is not completely captured by the secondary dust removal.

[0045] The application scenarios of the present invention are first introduced here.

[0046] An embodiment of the present invention provides a dust removal system, which includes an analysis device, a bag dust collector, and a monitoring device installed in an exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device.

[0047] The bag dust collector includes a controller, multiple chambers, a dust cleaning device corresponding to each chamber, an intermediate air duct, a clean air chamber and an exhaust duct.

[0048] Each chamber includes multiple bags (for example, coated polyester needle-punched felt filter bags), which are used to filter the dust-laden gas entering from the air inlet of the chamber, and then discharge the filtered gas from the air outlet of the chamber. The filtered gas can then enter the clean air chamber through the intermediate air duct and be discharged through the exhaust duct.

[0049] Each chamber has a poppet valve, and a cylinder drives the valve plate of the poppet valve up and down. The poppet valve is closed during chamber cleaning and maintenance, and open otherwise. When the poppet valve is closed, the chamber's air inlet and outlet are both closed, putting the chamber in an "offline" state; when the poppet valve is open, the chamber's air inlet and outlet are both open.

[0050] When the bag filter is started, each chamber can filter dust. The working cycle of the bag filter is T0, and the cleaning period within one working cycle is T1. The relationship between the two can be T0 ≥ T1.

[0051] Please combine Figure 1 , the working cycle of the bag dust collector is divided into the following two situations:

[0052] (1) When T0>T1, the working cycle T0 = full operation cycle T2 + cleaning cycle T1. During the full operation cycle of a working cycle, each chamber performs dust filtration; and during the cleaning cycle of a working cycle, each chamber will perform dust cleaning in turn (while one chamber is cleaning, the other chambers perform dust filtration). For example, T1 can be 30 minutes, 45 minutes, 50 minutes, etc., and T2 can be 5 minutes, 10 minutes, etc. This example is only an example. The size of T1 and T2 is set according to the scale of the bag dust collector, the amount of dust, etc., and is not limited here.

[0053] (2) When T0=T1, each chamber is cleaned in turn during the entire working cycle (i.e. the entire cleaning cycle).

[0054] During a cleaning cycle, the controller controls the cleaning device to clean each chamber in turn, and the cleaning time for each chamber is the uniformly preset single-chamber cleaning time. For any chamber A: during cleaning, the controller can control the lifting valve of chamber A to close, and then start the cleaning device to perform multiple pulse sprays on all bags in chamber A, that is, the pulse valve of the cleaning device instantly releases high-pressure compressed air, and injects high-speed airflow from the top of the bag (clean air side) into the inside of the bag through the nozzle on the spray pipe. The airflow then penetrates the bag wall and flows from the inside to the outside (from the inside of the bag to the dust-containing side), forming a reverse impact force, causing the dust layer attached to the outer surface of the bag to break, fall off, and fall into the ash hopper at the bottom of chamber A. After cleaning is completed, the controller can control the lifting valve of chamber A to open, so that chamber A continues to filter dust.

[0055] The monitoring device can be a dust concentration meter or a continuous emission monitoring system (CEMS). The monitoring device is used to collect the particle concentration of the exhaust gas from the exhaust duct at a preset collection frequency during the operation of the bag filter, and transmit the collected particle concentration in real time to the analysis device for storage.

[0056] The analysis device may be a computing device such as a laptop, a personal computer, or a server. The analysis device is used to analyze the concentration data of each dust cleaning cycle of the bag filter using the method for troubleshooting abnormal particle concentration provided by the embodiment of the present invention.

[0057] Optionally, the dust removal system provided by the present invention can be applied to the converter operation area of a steel plant, dust removal stages such as molten iron pouring station dust removal, molten iron (desulfurization) pretreatment dust removal, refining dust removal, converter secondary dust removal, and converter tertiary dust removal. It can also be applied to the dust removal stages of industries such as the cement industry, coal-fired power plants, and waste incineration plants.

[0058] Please refer to Figure 2 , Figure 2 The present invention provides a flowchart of a method for troubleshooting abnormal particle concentration. The method is executed by the above-mentioned analysis device and includes the following steps S201 to S205.

[0059] S201. During each cleaning cycle of the bag filter, concentration data collected by the monitoring equipment during the cleaning cycle is obtained.

[0060] In this embodiment, the concentration data includes the concentrations of particulate matter at several different collection moments.

[0061] S202: Based on the concentration data, the average particle concentration corresponding to the cleaning period of each chamber in the cleaning cycle is calculated respectively.

[0062] In this embodiment, since each chamber is cleaned in turn during the cleaning cycle, each chamber corresponds to a cleaning period, so the average particulate matter concentration corresponding to the cleaning period of each chamber can be calculated based on the concentration data.

[0063] S203. For each cleaning period in the current cleaning cycle, calculate the difference between the average particle concentration corresponding to the cleaning period and the average particle concentration corresponding to the previous cleaning period adjacent to the cleaning period, and obtain the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle.

[0064] In this embodiment, the cross-time period concentration change value may reflect the change in particle concentration between two adjacent cleaning time periods.

[0065] S204. For each chamber, calculate the difference between the average particle concentration corresponding to the chamber's cleaning period in the current cleaning cycle and the average particle concentration corresponding to the chamber's cleaning period in the previous cleaning cycle, and obtain the cross-cycle concentration change value corresponding to each chamber in the current cleaning cycle.

[0066] In this embodiment, the cross-cycle concentration change value may reflect the change in particle concentration between two cleaning periods in two adjacent cleaning cycles in the same chamber.

[0067] S205: Generate a troubleshooting prompt based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber.

[0068] In this embodiment, the troubleshooting prompt is used to remind maintenance personnel of the compartments to be checked and the factors to be checked.

[0069] The method for troubleshooting abnormal particle concentrations provided by an embodiment of the present invention is applied to a dust removal system, which includes an analysis device, a bag dust collector, and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device, and the bag dust collector includes multiple chambers and intermediate air ducts. The analysis device can use the monitoring device to collect all particle concentrations during the cleaning cycle to analyze the average particle concentration corresponding to the cleaning period of each chamber. After calculating the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle and the cross-cycle concentration change value corresponding to each chamber, a troubleshooting prompt can be generated. The troubleshooting prompt can prompt maintenance personnel to check the chambers and / or factors to be checked. Therefore, the present invention can achieve targeted troubleshooting without the need for manual carpet-style troubleshooting, saving troubleshooting time.

[0070] In an optional implementation, the analysis device includes a local storage area, and the method may further include S101 to S102.

[0071] S101: Receive the particulate matter concentration and its collection time sent regularly by the monitoring device, and store the received particulate matter concentration and its collection time in a local storage area.

[0072] In this embodiment, the monitoring device collects particulate matter concentration at a preset collection frequency. For example, the preset collection frequency may be once every 30 ms, once every 100 ms, etc. The actual value of the preset collection frequency depends on the actual situation and is not limited here.

[0073] Optionally, the particle concentration in the local storage area that was collected m days ago can be cleared every day. In this way, the local storage area can only store the particle concentration collected within the last m days (for example, 7 days or 30 days) to reduce storage pressure.

[0074] S102: If the data sent by the monitoring device is not received within the preset time, the maintenance personnel are prompted to check whether the monitoring device has a fault, or whether there is a communication fault between the analysis device and the monitoring device.

[0075] In this embodiment, assuming that the monitoring device collects data once every 30 ms, the analysis device can receive the particulate matter concentration and its collection time every 30 ms. If the analysis device does not receive the particulate matter concentration reported by the monitoring device for a preset period of time (for example, 1 minute or 3 minutes), it is likely that the monitoring device has failed, or there is a communication failure between the monitoring device and the analysis device, and maintenance personnel need to check it in time.

[0076] Therefore, in S201, for the time period of the most recent cleaning cycle, each particle concentration and its collection time within the time period of the most recent cleaning cycle can be obtained from the local storage area to obtain concentration data.

[0077] Optionally, the sub-steps of step S202 may include S2021 and S2022:

[0078] S2021. Based on the preset single-bin cleaning time, determine the cleaning time period for each bin in the cleaning cycle period;

[0079] S2022. For each chamber, find out from the concentration data the concentration of each particle that is within the chamber's dust cleaning period at the time of collection, and calculate the average of all the found particle concentrations to obtain the average particle concentration corresponding to the chamber's dust cleaning period.

[0080] In this embodiment, assuming the bag filter includes K chambers (chamber 1 through chamber K), chambers 1 through chamber K are cleaned sequentially during a cleaning cycle, so the K cleaning periods within a cleaning cycle are connected sequentially. The value of K depends on the specifications of the bag filter. For example, small bag filters can have 4, 6, or 8 chambers, while large bag filters can have 16, 24, or 36 chambers. This embodiment of the present invention does not impose any restrictions on the number of chambers in a bag filter.

[0081] Assume that the bag filter has a total of 8 chambers (chamber 1 to chamber 8), the cleaning cycle T1 is 16 minutes, and the cleaning time of a single chamber is 2 minutes. Figure 3If the most recent cleaning cycle is 10:00:00~10:16:00, then the cleaning periods for chambers 1~8 are Figure 3 The example is only an example and is not limiting.

[0082] In an optional implementation, a concentration change trend graph within a cleaning cycle can also be generated to facilitate maintenance personnel to view the changes in particle concentration during the cleaning period of each chamber within a cleaning cycle. Correspondingly, after the above step S202, the method can also include the following steps S206-S209.

[0083] S206: Generate a concentration change curve of the cleaning cycle based on the concentration of each particle in the concentration data and its collection time.

[0084] In this embodiment, for each cleaning cycle, a concentration variation curve can be generated using the concentration data of the cleaning cycle.

[0085] S207: Construct a cleaning progress line based on the cleaning period of each chamber in the cleaning cycle.

[0086] In this embodiment, the cleaning progress line can reflect the cleaning period and cleaning sequence of each chamber.

[0087] Optionally, one or two control points can be constructed for each cleaning period, and then all control points can be connected in sequence to obtain a cleaning progress line. The cleaning progress line can be of three types: broken line, step line, or square wave. Correspondingly, the construction of the control points also has the following three control methods:

[0088] The first control point construction method uses a broken line type cleaning progress line. In this case, only one control point is required for each control period. Therefore, the process of "constructing a control point corresponding to each cleaning period" can include the following steps:

[0089] (1) For the first dust cleaning period, the first control point is constructed with the start time of the first dust cleaning period as the horizontal coordinate and the preset first height value as the vertical coordinate;

[0090] (2) For the kth cleaning period, if k is an even number, the ordinate of the k-1th control point is increased by a preset step size to obtain the kth height value; if k is an odd number, the ordinate of the k-1th control point is reduced by a preset step size to obtain the kth height value. The kth control point is constructed with the start time of the kth cleaning period as the horizontal coordinate and the kth height value as the vertical coordinate; where k = 2, 3, 4, ..., K.

[0091] The second control point construction method uses a square wave type cleaning progress line. In this case, two control points are required for each control period. Therefore, the process of "constructing two control points corresponding to each cleaning period" can include the following steps:

[0092] (1) For the first cleaning period, construct two control points corresponding to the first cleaning period with the start and end times of the first cleaning period as the horizontal coordinates and the preset first height value as the vertical coordinate;

[0093] (2) For the kth cleaning period, if k is an even number, the vertical coordinate of the control point corresponding to the end time of the k-1th cleaning period is increased by a preset step size to obtain the kth height value; if k is an odd number, the vertical coordinate of the control point corresponding to the end time of the k-1th cleaning period is reduced by a preset step size to obtain the kth height value. The two control points corresponding to the kth cleaning period are constructed with the start time and end time of the kth cleaning period as the horizontal coordinates and the kth height value as the vertical coordinate.

[0094] The third control point construction method uses a step line type (increasing step line or decreasing step line) to construct the cleaning progress line. In this case, two control points are required for each control period. Therefore, the process of "constructing two control points corresponding to each cleaning period" can include the following steps:

[0095] For the first dust cleaning period, construct two control points corresponding to the first dust cleaning period with the start time and end time of the first dust cleaning period as the horizontal coordinate and the preset first height value as the vertical coordinate;

[0096] For the kth cleaning period, the vertical coordinate of the control point corresponding to the end time of the k-1th cleaning period is increased or decreased by a preset step size to obtain the kth height value. The start time and end time of the kth cleaning period are used as the horizontal coordinates and the kth height value is used as the vertical coordinate to construct two control points corresponding to the kth cleaning period.

[0097] It should be noted that the vertical coordinate of the cleaning progress line is only for distinguishing each cleaning period from the height difference, so the first height value and the size of the preset step can be set flexibly. For example, the first height value can be 0, 0.5, 1, 2, etc., and the preset step can be 0.2, 0.5, 1, etc. This example is only an example and is not limited here.

[0098] S208: Integrate the concentration change curve and the cleaning progress line to obtain a concentration change trend diagram of the cleaning cycle.

[0099] In this embodiment, the horizontal axis of the concentration change trend graph is time, and the vertical axis is concentration (unit: ), the concentration change trend graph can also include a reference horizontal line corresponding to a preset concentration threshold, so that maintenance personnel can check which time periods have an average particulate matter concentration that exceeds the concentration threshold.

[0100] In one example, Figure 3 Based on Figure 4 , if the first height value and the preset step size are 2 and 1 respectively, the concentration threshold is 9 , then in the concentration change trend graph, the first control point construction method mentioned above is used to obtain the broken line type cleaning progress line as follows Figure 4 shown.

[0101] Figure 4 During the entire cleaning cycle from 10:00:00 to 10:16:00, the particle concentration was maintained at 1~3 In between, relatively stable.

[0102] In another example, Figure 3 Based on Figure 5 , if the first height value and the preset step size are 2 and 1 respectively, the concentration threshold is 9 Then, in the concentration change trend graph, the second control point construction method mentioned above is used to obtain the square wave type cleaning progress line as follows: Figure 5 shown.

[0103] Figure 6 During the entire cleaning cycle from 10:00:00 to 10:16:00, the particle concentration in periods 1 to 4 was maintained at 3 to 5. However, in period 4, the particulate matter concentration abnormally increased and exceeded the reference level, and in the subsequent periods 6 to 8, it remained close to the reference level.

[0104] It should be noted that Figure 4 、 Figure 5 and Figure 6 The image shown is only within one cleaning cycle, which is only an example and is not limited here. The actual concentration change trend diagram may include concentration change curves of multiple consecutive working cycles, for example, Figure 7 The continuous concentration change trend diagram shown shows the concentration change curve of the bag dust collector including 36 chambers during two complete working cycles.

[0105] The present invention determines the average particle concentration corresponding to the cleaning period of each of the K bins of the bag filter in each cleaning cycle through the above steps S201 and S202. Figure 3 Based on Figure 8 , the following combination Figure 8The method of calculating the concentration change value across time periods in step S203 and the method of calculating the concentration change value across cycles in step S204 are described respectively:

[0106] Combine Figure 8 ,by Figure 8 Take the dust cleaning period of the middle chamber 8 (i.e. period 8) as an example:

[0107] (1) The cross-period concentration change value Δ1 corresponding to period 8 = the average particle concentration value corresponding to period 8 - the average particle concentration value corresponding to period 7;

[0108] (2) The cross-cycle concentration change value Δ2 corresponding to chamber 8 = the average particle concentration value corresponding to period 8 - the average particle concentration value corresponding to the previous cleaning period of chamber 8.

[0109] It should be noted that Figure 8 The examples shown are for example only and are not limiting.

[0110] In an optional implementation, the process of "generating troubleshooting prompts based on the cross-period concentration change values corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change values corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber" in the above step S205 may include the following sub-steps S2051~S2053.

[0111] S2051. If the cross-period concentration change values corresponding to at least M consecutive cleaning periods in the current cleaning cycle are all positive numbers, the maintenance personnel are prompted to check whether there are weld cracks at the connections between each chamber and the intermediate air duct that have been cleaned in at least M consecutive cleaning periods.

[0112] In this embodiment, it is necessary to determine whether there are at least M (M can be 3 or 5, etc.) consecutive cleaning periods in the current cleaning cycle, and the concentration change values corresponding to the periods are all positive numbers. If so, an alarm can be triggered (for example, an audible and visual alarm), and the generated troubleshooting prompt can be: Please ask maintenance personnel to check whether there are any weld cracks in the middle air duct.

[0113] Assume M=3, combined Figure 5 During the entire cleaning cycle from 10:00:00 to 10:16:00, the particle concentration in periods 1 to 3 was maintained at 2 to 3.5. However, from period 4 to period 8, the particle concentration continues to increase. Obviously, the cross-period concentration change values corresponding to period 5 to period 8 are all positive numbers. It is possible that the weld in the middle air duct suddenly cracked at the beginning of period 5, resulting in a crack.

[0114] Because under normal circumstances, the middle air duct should remain sealed, and the collected particle concentration should maintain a small fluctuation but relatively stable state (for example Figure 4 However, during the dust cleaning period of chamber 5, if a crack appears in the middle air duct, then from the moment the crack appears, the dust-laden gas outside the bag filter will continue to flow into the middle air duct through the crack, and then enter the clean air chamber and be discharged with the filtered gas. As time goes by, the crack may gradually become larger, showing as follows: Figure 5 The concentration of particulate matter continued to rise from period 5 to period 8. Therefore, it was necessary to promptly identify the location of the crack at the connection between chambers 5 to 8 and the middle air duct.

[0115] This example is merely an example and is not intended to be limiting.

[0116] S2052. If the cross-cycle concentration change values corresponding to the target chamber in N consecutive cleaning cycles are all positive numbers, the maintenance personnel are prompted to check whether there is any bag damage in the chamber that was cleaned before the target chamber.

[0117] In this embodiment, it is necessary to determine whether there is a target chamber whose corresponding cross-cycle concentration change values in N consecutive cleaning cycles are all positive numbers. If so, an alarm can be triggered (for example, an audible and visual alarm), and the generated troubleshooting prompt can be: Please ask maintenance personnel to check whether there is any bag damage in the chamber that was cleaned before the target chamber.

[0118] Because under normal circumstances, the middle air duct should remain sealed, and the collected particle concentration should maintain a small fluctuation but relatively stable state (for example Figure 4 The fluctuation amplitude of the concentration change curve is smaller. If the bag in compartment k-1 suddenly breaks during cleaning, resulting in a small hole, some dust will enter the bag through the hole and accumulate inside the bag during the current cleaning period of compartment k-1. Because the lift valve is closed, the particle concentration collected by the monitoring equipment during the current cleaning period of compartment k-1 will not increase abnormally. However, when compartment k is subsequently started for cleaning, the moment compartment k-1 resumes filtering, the large amount of dust accumulated inside compartment k-1 will enter the clean air chamber and be discharged with the filtered air. This will cause the particle concentration collected by the monitoring equipment during the current cleaning period of compartment k to increase momentarily. As time passes, the hole gradually increases, and more dust will accumulate in the broken bag in compartment k-1 during the next cleaning period, resulting in a higher particle concentration collected by the monitoring equipment during the next cleaning period of compartment k. In this way, the average particle concentration corresponding to multiple consecutive cleaning periods of compartment k will continue to increase. Therefore, it is necessary to open chamber k-1, find the damaged bag, and replace it with a new one.

[0119] S2053. If, in the current cleaning cycle, the average particulate matter concentrations corresponding to multiple consecutive cleaning periods corresponding to multiple target chambers exceed the preset concentration threshold, the maintenance personnel are prompted to check whether there is any bag detachment in the chamber that was cleaned before the first target chamber.

[0120] In this embodiment, it is necessary to determine whether in the current cleaning cycle, the average particulate matter concentrations corresponding to multiple cleaning periods corresponding to multiple target chambers all exceed the preset concentration threshold. If so, an alarm can be triggered (for example, an audible and visual alarm), and the generated troubleshooting prompt can be: Please ask maintenance personnel to check whether there is any bag detachment in the chamber that was cleaned before the first target chamber.

[0121] If the bag suddenly falls off during cleaning in chamber k-1 (this situation is generally rare), the particulate matter concentration collected by the monitoring equipment during the cleaning period of chamber k-1 will not increase abnormally due to the closed lift valve. However, from the moment chamber k starts cleaning, a large amount of unfiltered dust-laden gas in chamber k-1 will continuously enter the clean air chamber through the outlet of the detached bag and be discharged with the filtered gas. This causes the particulate matter concentration to rise rapidly from the cleaning period of chamber k. As a result, the collected particulate matter concentration may remain above the concentration threshold in each cleaning period from chamber k to chamber K. The collected particulate matter concentration will not drop to normal until chamber k-1 enters the cleaning period of the next cleaning cycle. Therefore, it is necessary to open chamber k-1, find the location where the bag fell off, and re-attach a bag.

[0122] This example is merely an example and is not intended to be limiting.

[0123] Optionally, if the emission standard requires that the concentration of particulate matter in the gas discharged after the bag filter performs dust filtration is not allowed to exceed , then in order to reserve a certain amount of time for investigation, the concentration threshold can be set to or In this way, if a bag filter malfunctions and its dust filtering capacity decreases, if the particle concentration collected by the monitoring equipment exceeds the concentration threshold, there will be time to conduct timely troubleshooting and repair, preventing the particle concentration from continuing to rise and exceeding the emission standards, causing air pollution.

[0124] S2054: If, in the current cleaning cycle, the average particle concentration corresponding to the cleaning period of only one target chamber exceeds the preset concentration threshold, the maintenance personnel are prompted to check whether the lift valve in the target chamber is faulty.

[0125] In this embodiment, it is necessary to determine whether in the current cleaning cycle, there is only one target chamber whose average particulate matter concentration corresponding to the cleaning period exceeds the preset concentration threshold. If so, an alarm can be triggered (for example, an audible and visual alarm), and the generated troubleshooting prompt can be: Please ask maintenance personnel to check whether the lifting valve in the target chamber is faulty.

[0126] This is because if the poppet valve of chamber k is faulty (for example, the poppet valve is not tightly sealed, the poppet valve cylinder is faulty, the poppet valve solenoid valve is faulty, etc.), then when chamber k enters the cleaning period, the air inlet and outlet of chamber k may only be partially closed or cannot be closed, allowing external dust-laden gas to continue to enter chamber k during the cleaning period. At this time, the airflow generated by the pulse injection is from the inside to the outside, but the pressure inside the chamber may change due to the continuous entry of external airflow. At this time, the pulse airflow may conflict with the dust-laden airflow, causing dust to be carried from the air outlet that has never been closed or not completely closed to the clean air chamber and discharged with the filtered gas, resulting in an abnormal increase in the particle concentration collected by the monitoring equipment during the cleaning period of chamber k. After the cleaning of chamber k is completed, the collected particle concentration returns to normal. Therefore, it is necessary to open chamber k, find the cause of the poppet valve failure, and repair it in a timely manner.

[0127] It should be noted that the execution order of the steps in the above method embodiment is not limited to that shown in the drawings, and the execution order of the steps shall be based on actual application conditions.

[0128] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0129] The present invention can not only monitor the changes in the concentration of particulate matter in the exhaust gas of the bag filter in real time, but also promptly detect the abnormality, issue an alarm and provide troubleshooting prompts when the concentration of particulate matter is abnormal;

[0130] The troubleshooting prompts generated by this invention accurately indicate the location of the chamber to be inspected and the factors to be investigated. This provides maintenance personnel with detailed fault information for targeted troubleshooting, eliminating the need for extensive manual inspections. This saves time and prevents excessive particulate matter concentrations in exhaust gases, which can cause air pollution. Targeted troubleshooting also helps quickly restore the system to normal operation, improving production efficiency and equipment reliability.

[0131] In order to execute the corresponding steps in the above method embodiment and various possible implementations, an implementation method of a device for checking abnormal particle concentration is provided below.

[0132] See Figure 9 , Figure 9The schematic diagram of the structure of the device for checking abnormal particle concentration provided by an embodiment of the present invention is shown. The device 200 for checking abnormal particle concentration is applied to an analysis device in a dust removal system. The dust removal system also includes a bag dust collector and a monitoring device installed in the exhaust duct of the bag dust collector. The monitoring device is in communication with the analysis device. The bag dust collector includes multiple chambers and an intermediate air duct. The device 200 for checking abnormal particle concentration includes:

[0133] The data acquisition module 210 is used to acquire concentration data collected by the monitoring device during each cleaning cycle of the bag filter; the concentration data includes the concentration of particulate matter at several different collection moments;

[0134] The calculation module 220 calculates the average particulate matter concentration corresponding to the cleaning period of each chamber in the cleaning cycle based on the concentration data;

[0135] The calculation module 220 is further configured to calculate, for each cleaning period in the current cleaning cycle, the difference between the average particle concentration corresponding to the cleaning period and the average particle concentration corresponding to the previous cleaning period adjacent to the cleaning period, thereby obtaining a concentration change value across the cleaning period corresponding to each cleaning period in the current cleaning cycle;

[0136] The calculation module 220 is further configured to calculate, for each chamber, the difference between the average particle concentration corresponding to the cleaning period of the chamber in the current cleaning cycle and the average particle concentration corresponding to the cleaning period of the chamber in the previous cleaning cycle, to obtain a concentration change value corresponding to each chamber across the cleaning cycle.

[0137] The prompt module 230 is used to generate an inspection prompt based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber. The inspection prompt is used to prompt maintenance personnel to check the chambers and factors to be checked.

[0138] Optionally, the data acquisition module 210 can be used to implement steps S101-S102 and S201, the calculation module 220 can be used to implement steps S202-S204 and their respective sub-steps, and the prompt module 230 can be used to implement step S205 and its sub-steps. The device 200 for troubleshooting abnormal particulate matter concentrations can also include a graph output module 240, which can be used to implement steps S206-S209 and their respective sub-steps.

[0139] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device 200 for checking abnormal particle concentration described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0140] See Figure 10 , Figure 10 This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device 300 includes a processor 310 , a memory 320 , and a bus 330 , wherein the processor 310 is connected to the memory 320 via the bus 330 .

[0141] Memory 320 can be used to store software programs, such as the software program corresponding to the device 200 for troubleshooting abnormal particulate matter concentration provided in an embodiment of the present invention. Processor 310 executes the software program stored in memory 320 to perform various functional applications and data processing to implement the method for troubleshooting abnormal particulate matter concentration provided in an embodiment of the present invention.

[0142] Among them, the memory 320 can be but is not limited to: RAM (Random Access Memory), ROM (Read Only Memory), FLASH (Flash Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electric Erasable Programmable Read-Only Memory), etc.

[0143] Processor 310 can be an integrated circuit chip with signal processing capabilities. Processor 310 can be a general-purpose processor, including a CPU (Central Processing Unit), a Network Processor (NP), or a System on Chip (SoC). It can also be a DSP (Digital Signal Processing), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0144] I understand. Figure 10 The structure shown is for illustration only. The electronic device 300 may also include Figure 10 More or fewer components than shown, or with Figure 10Different configurations shown. Figure 10 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0145] In summary, the embodiments of the present invention provide a method, device, electronic equipment and dust removal system for troubleshooting abnormal particle concentrations. The dust removal system includes an analysis device, a bag dust collector and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is communicatively connected to the analysis device, and the bag dust collector includes multiple chambers and intermediate air ducts. The analysis device can use the monitoring device to collect all particle concentrations during the cleaning cycle to analyze the average particle concentration corresponding to the cleaning period of each chamber. After calculating the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle and the cross-cycle concentration change value corresponding to each chamber, a troubleshooting prompt can be generated. The troubleshooting prompt can prompt maintenance personnel to check the chambers and / or factors to be checked. Therefore, the present invention can achieve targeted troubleshooting without the need for manual carpet-style troubleshooting, saving troubleshooting time.

[0146] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for checking abnormal particle concentration, characterized in that: An analysis device is used in a dust removal system, the dust removal system also including a bag dust collector and a monitoring device installed in an exhaust duct of the bag dust collector; the monitoring device is in communication with the analysis device, and the bag dust collector includes multiple chambers and an intermediate air duct; the method includes: During each cleaning cycle of the bag filter, concentration data collected by the monitoring device during the cleaning cycle is obtained; the concentration data includes particle concentrations at several different collection moments; Based on the concentration data, respectively calculating the average particulate matter concentration corresponding to the cleaning period of each chamber in the cleaning cycle; For each cleaning period in the current cleaning cycle, calculate the difference between the average particle concentration corresponding to the cleaning period and the average particle concentration corresponding to the previous cleaning period adjacent to the cleaning period, and obtain the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle; For each chamber, calculate the difference between the average particle concentration corresponding to the cleaning period of the chamber in the current cleaning cycle and the average particle concentration corresponding to the cleaning period of the chamber in the previous cleaning cycle, and obtain the cross-cycle concentration change value corresponding to each chamber in the current cleaning cycle; Based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber, an investigation prompt is generated. The investigation prompt is used to prompt maintenance personnel to check the chambers and factors to be checked.

2. The method for checking abnormal particle concentration according to claim 1, characterized in that: The step of calculating the average particulate matter concentration corresponding to the cleaning period of each chamber in the cleaning cycle based on the concentration data includes: Based on the preset single-bin cleaning time, sequentially determine the cleaning time period for each bin in the cleaning cycle period; For each of the chambers, each particle concentration within the chamber's dust cleaning period at the time of collection is found from the concentration data, and the average of all the found particle concentrations is calculated to obtain the average particle concentration corresponding to the chamber's dust cleaning period.

3. The method for checking abnormal particle concentration according to claim 1, characterized in that: The analysis device includes a local storage area; before the step of obtaining concentration data collected by the monitoring device during each cleaning cycle of the bag filter, the method further includes: receiving the particulate matter concentration and its collection time sent regularly by the monitoring device, and storing the received particulate matter concentration and its collection time in the local storage area; the particulate matter concentration is collected by the monitoring device according to a preset collection frequency; If the data sent by the monitoring device is not received within the preset time, the maintenance personnel are prompted to check whether the monitoring device is faulty, or whether there is a communication failure between the analysis device and the monitoring device.

4. The method for checking abnormal particle concentration according to claim 1, characterized in that: The cleaning cycle includes cleaning periods for K chambers, and the K cleaning periods are connected in sequence. After the step of calculating, based on the concentration data, the average particulate matter concentration corresponding to the cleaning period of each chamber in the cleaning cycle, the method further includes: generating a concentration change curve of the cleaning cycle based on the concentration of each particle in the concentration data and the time of collection; Based on the cleaning period of each chamber within the cleaning cycle, a cleaning progress line is constructed; the cleaning progress line reflects the cleaning period and cleaning order of each chamber; The concentration change curve and the cleaning progress line are integrated to obtain a concentration change trend diagram of the cleaning cycle, wherein the abscissa of the concentration change trend diagram is time and the ordinate is concentration.

5. The method for checking abnormal particle concentration according to claim 4, characterized in that: The step of constructing a cleaning progress line based on the cleaning period of each chamber in the cleaning cycle includes: Constructing one or two control points corresponding to each dust cleaning period; All control points are connected in sequence to obtain the dust cleaning progress line.

6. The method for checking abnormal particle concentration according to claim 5, characterized in that: The step of constructing one or two control points corresponding to each cleaning period includes: For the first dust cleaning period, the first control point is constructed with the start time of the first dust cleaning period as the horizontal coordinate and the preset first height value as the vertical coordinate; For the k-th cleaning period, if k is an even number, the ordinate of the k-1-th control point is increased by a preset step size to obtain the k-th height value; if k is an odd number, the ordinate of the k-1-th control point is reduced by the preset step size to obtain the k-th height value. The k-th control point is constructed with the start time of the k-th cleaning period as the abscissa and the k-th height value as the ordinate; Alternatively, for the first dust cleaning period, two control points corresponding to the first dust cleaning period are constructed with the start time and the end time of the first dust cleaning period as the horizontal coordinates and the first height value as the vertical coordinate; For the kth cleaning period, if k is an even number, the ordinate of the control point corresponding to the end time of the k-1th cleaning period is increased by a preset step size to obtain the kth height value; if k is an odd number, the ordinate of the control point corresponding to the end time of the k-1th cleaning period is reduced by the preset step size to obtain the kth height value, and the two control points corresponding to the kth cleaning period are constructed with the start time and end time of the kth cleaning period as the abscissa and the kth height value as the ordinate; or, For the first dust cleaning period, construct two control points corresponding to the first dust cleaning period with the start time and end time of the first dust cleaning period as the horizontal coordinate and the preset first height value as the vertical coordinate; For the kth cleaning period, the vertical coordinate of the control point corresponding to the end time of the k-1th cleaning period is increased or decreased by a preset step size to obtain the kth height value, and the start time and end time of the kth cleaning period are used as the horizontal coordinates and the kth height value is used as the vertical coordinate to construct two control points corresponding to the kth cleaning period; wherein, k=2,3,4,…,K.

7. The method for checking abnormal particle concentration according to claim 1, characterized in that: The step of generating a troubleshooting prompt based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-period concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber includes: If the concentration change values across time periods corresponding to at least M consecutive cleaning periods in the current cleaning cycle are all positive, the maintenance personnel are prompted to check whether there are any weld cracks at the connection between each chamber cleaned in at least M consecutive cleaning periods and the intermediate air duct; If the concentration change values of the target chamber corresponding to N consecutive cleaning cycles are all positive, the maintenance personnel will be prompted to check whether there is any bag damage in the chamber that was cleaned before the target chamber; If, in the current cleaning cycle, the average particulate matter concentrations corresponding to multiple consecutive cleaning periods corresponding to multiple target chambers all exceed the preset concentration threshold, the maintenance personnel are prompted to check whether there is any bag detachment in the chamber that was cleaned before the first target chamber; If, in the current cleaning cycle, the average particle concentration corresponding to the cleaning period of only one target chamber exceeds the preset concentration threshold, the maintenance personnel will be prompted to check whether the lifting valve in the target chamber is faulty.

8. A device for checking abnormal particle concentration, characterized in that: An analytical device for use in a dust removal system, the dust removal system also including a bag dust collector and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is in communication with the analytical device; the bag dust collector includes multiple chambers and an intermediate air duct; the device includes: A data acquisition module is used to acquire concentration data collected by the monitoring device during each cleaning cycle of the bag filter; the concentration data includes the concentration of particulate matter at several different collection moments; a calculation module, which calculates, based on the concentration data, an average particulate matter concentration corresponding to a cleaning period of each chamber in the cleaning cycle; The calculation module is further configured to calculate, for each cleaning period in the current cleaning cycle, a difference between an average particle concentration corresponding to the cleaning period and an average particle concentration corresponding to a previous cleaning period adjacent to the cleaning period, to obtain an inter-period concentration change value corresponding to each cleaning period in the current cleaning cycle; The calculation module is further configured to calculate, for each chamber, a difference between an average particle concentration corresponding to a cleaning period of the chamber in a current cleaning cycle and an average particle concentration corresponding to a cleaning period of the chamber in a previous cleaning cycle, to obtain an inter-cycle concentration change value corresponding to each chamber in the current cleaning cycle; The prompt module is used to generate an inspection prompt based on the cross-period concentration change value corresponding to each cleaning period in the current cleaning cycle, the cross-cycle concentration change value corresponding to each chamber, and the average particulate matter concentration corresponding to the cleaning period of each chamber. The inspection prompt is used to prompt maintenance personnel to check the chambers and factors to be checked.

9. An electronic device, characterized in that: include: A memory and a processor, wherein the memory stores a software program, and when the electronic device is running, the processor executes the software program to implement the method for troubleshooting abnormal particulate matter concentration according to any one of claims 1 to 7.

10. A dust removal system, characterized in that: The dust removal system includes an analysis device, a bag dust collector, and a monitoring device installed in the exhaust duct of the bag dust collector; the monitoring device is in communication with the analysis device; The monitoring device is used to collect the particle concentration of the gas discharged from the exhaust pipe according to a preset collection frequency during the operation of the bag filter, and send the collected particle concentration to the analysis device in real time for storage; The analysis device is used to analyze the concentration data of each cleaning cycle of the bag filter according to the method for troubleshooting abnormal particle concentration according to any one of claims 1 to 7.

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