Method and system for diagnosing deterioration of metal filters

Abstract

[Problem] To provide: a method for diagnosing deterioration of a metal filter which makes it possible to accurately diagnose metal filter deterioration, regardless of whether a dust collector is operating or stopped; and a deterioration diagnosis system. [Solution] Provided is a method for diagnosing deterioration of a metal filter 6 according to the present invention, said method being characterized in that an electrical property value (electrical resistance value) of the metal filter 6 is detected, and the deterioration of the metal filter 6 is diagnosed on the basis of the detected electrical property value. Further provided is a deterioration diagnosis system for a metal filter 6 according to the present invention which is equipped with: a power supply device 21 for conducting electricity to the metal filter 6; a resistance measurement device 22 for detecting an electrical property value (electrical resistance value) of the metal filter 6; a transmitter 30 for transmitting the electrical property value (electrical resistance value) of the metal filter 6 as a signal; a receiver 40 for receiving the electrical property value signal (electrical resistance value signal) transmitted by said transmitter 30; and a deterioration diagnosis device 60 for diagnosing deterioration of the metal filter 6 on the basis of the electrical property value signal received by the receiver 40.

Description

[Technical Field]

[0001] The present invention relates to a method and system for diagnosing the deterioration of a metal filter equipped in a dust collector for removing foreign matter such as dust contained in gas. [Background technology]

[0002] For example, various gases emitted from blast furnaces, electric furnaces, and waste treatment furnaces contain foreign matter such as dust, so dust collectors are used to remove this foreign matter.

[0003] The dust collectors commonly used are those employing an external filtration type bag filter, and these bag filters are typically made of cloth, such as nonwoven fabric. In dust collectors equipped with such bag filters, foreign matter contained in the gas is removed (collected) as gas flows from the outside to the inside of the bag filter. Consequently, as dust collection progresses, foreign matter adheres to the outer surface of the bag filter, and the bag filter becomes clogged, increasing the airflow resistance (pressure loss) of the gas passing through the bag filter, which reduces the purification capacity of the dust collector.

[0004] Therefore, the differential pressure (pressure loss) inside and outside the bag filter is detected, and if the detected differential pressure increases beyond a predetermined threshold, high-pressure compressed air is instantaneously injected into each bag filter to periodically brush off and remove any foreign matter adhering to the bag filter in a backwashing process.

[0005] Incidentally, Patent Document 1 proposes an operating method for an ash treatment device that detects the differential pressure before and after gas inflow into a bag filter and determines the injection interval of backwash gas during backwashing based on the detected differential pressure.

[0006] Furthermore, Patent Documents 2 and 3 propose an online diagnostic system that detects the differential pressure before and after gas inflow into a dust collection filter, transmits the detected differential pressure data to a diagnostic device via an internet connection, and uses the diagnostic device to determine when the dust collection filter needs to be replaced.

[0007] On the other hand, Patent Document 4 proposes a dust collector that detects the temperature inside the dust collector body and the temperature of the dust collection filter, and determines that the device is in an abnormal state if the difference between the two temperatures exceeds a predetermined value.

[0008] Furthermore, Patent Document 5 proposes a filter cloth damage detection method in which conductive carbon fibers are woven in the longitudinal direction of the dust collection filter (filter cloth), and a DC current is passed through these carbon fibers from a constant current source via a closed-loop circuit. Damage to the dust collection filter is detected when the current flowing through the carbon fibers stops due to a tear in the dust collection filter (breakage of the carbon fibers). [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2020-062626 [Patent Document 2] Japanese Patent Publication No. 2017-217616 [Patent Document 3] Japanese Patent Publication No. 2019-147097 [Patent Document 4] Japanese Patent Application Publication No. 6-246121 [Patent Document 5] Japanese Patent Publication No. 2001-054714 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, since the heat resistance temperature of cloth filters is lower than that of metal filters, the temperature of the gas that can be collected by cloth filters is also lower than that of metal filters. Therefore, there is a problem that the usable temperature range of cloth filters is narrower than that of metal filters.

[0011] Therefore, it is conceivable to use a highly heat-resistant metal filter in the filter installed in the dust collector. Factors that can cause deterioration of this metal filter include deterioration of the metal fibers (thinning of thickness) and clogging by foreign matter. However, the method of detecting metal filter deterioration by differential pressure (the difference between the gas inflow pressure and outflow pressure into the filter) proposed in Patent Documents 1 to 3 can only diagnose deterioration due to clogging of the metal filter. As mentioned above, factors that cause deterioration of a metal filter include deterioration of the metal fibers themselves in addition to clogging, but the methods disclosed in Patent Documents 1 to 3 cannot accurately diagnose metal filter deterioration that takes into account the deterioration of the metal fibers.

[0012] Furthermore, the methods proposed in Patent Documents 1 to 3 require the detection of differential pressure or temperature, which means that the diagnosis of filter deterioration can only be performed while the dust collector is in operation and cannot be performed when the dust collector is stopped.

[0013] Furthermore, the apparatus and methods proposed in Patent Documents 4 and 5 are intended for detecting abnormalities due to filter damage, and not for diagnosing the deterioration of metal filters.

[0014] The present invention has been made in view of the above problems, and its object is to provide a metal filter deterioration diagnosis method and deterioration diagnosis system that can accurately diagnose the deterioration of a metal filter, whether the dust collector is in operation or stopped. [Means for solving the problem]

[0015] To achieve the above objective, the present invention provides a method for diagnosing the deterioration of a metal filter in a dust collector, which is configured by dividing the interior of the main body into a dust collection chamber and a purified gas chamber by a partition wall and attaching a metal filter to the partition wall, characterized in that the electrical characteristic value of the metal filter is detected and the deterioration of the metal filter is diagnosed based on the detected electrical characteristic value.

[0016] Here, the electrical characteristic value is an electrical resistance value or a current value. When the electrical resistance value increases beyond a predetermined threshold or when the current value decreases beyond a predetermined threshold, the metal filter is diagnosed as being at the replacement time.

[0017] Also, it is desirable to detect the differential pressure between the dust collection chamber and the purified gas chamber and correct the threshold value of the electrical resistance value or the current value based on the detected differential pressure. In this case, as the detected differential pressure increases, the threshold value of the electrical resistance value is increased, or the threshold value of the current value is decreased. As the detected differential pressure decreases, the threshold value of the electrical resistance value is decreased, or the threshold value of the current value is increased.

[0018] Furthermore, when the differential pressure increases beyond a predetermined threshold, backwashing may be performed by injecting compressed air into the metal filter. Here, after a predetermined time has elapsed since the backwashing was performed, the electrical characteristic value of the metal filter may be detected to diagnose the deterioration of the metal filter. Also, the number of backwashes may be counted, and when the counted number exceeds a predetermined value or when the electrical resistance value or the current value of the metal filter exceeds a predetermined threshold, the metal filter may be diagnosed as being at the replacement time.

[0019] The present invention also relates to a deterioration diagnosis system for a metal filter of a dust collector configured by partitioning the interior of a main body into a dust collection chamber and a purified gas chamber by a partition wall and attaching a metal filter to the partition wall, the system including power supply means for energizing the metal filter, electrical characteristic value detection means for detecting the electrical characteristic value of the metal filter, transmission means for transmitting the electrical characteristic value of the metal filter detected by the electrical characteristic value detection means as a signal, reception means for receiving the electrical characteristic value signal transmitted from the transmission means, and deterioration diagnosis means for diagnosing the deterioration of the metal filter based on the electrical characteristic value signal received by the reception means.

[0020] In this case, an internet connection may be provided between the transmitting means and the receiving means, and the electrical characteristic value signal transmitted from the transmitting means may be transmitted to the receiving means via the internet connection.

[0021] Furthermore, a differential pressure detection means may be provided to detect the differential pressure between the dust collection chamber and the purified gas chamber. In this case, a backwashing means may be provided to inject compressed air into the metal filter when the differential pressure detected by the differential pressure detection means increases beyond a predetermined threshold.

[0022] Furthermore, the deterioration diagnosis means may include a notification means for notifying when it is time to replace the metal filter. The deterioration diagnosis means may also include a timer for measuring the time elapsed since the metal filter was backwashed by the backwashing means, and a counter for counting the number of backwashes. [Effects of the Invention]

[0023] According to the present invention, by energizing a metal filter and detecting its electrical characteristics (electrical resistance or current), the deterioration of the metal fibers themselves (including the deterioration of the metal filter, such as an increase in electrical resistance (decrease in current) due to the thinning of the metal fibers) can be accurately diagnosed based on the electrical characteristics of the metal filter. Furthermore, since it is possible to energize a metal filter and detect its electrical characteristics whether the dust collector is running or stopped, the deterioration of the metal filter can be diagnosed regardless of whether the dust collector is running or stopped.

[0024] Furthermore, by detecting the differential pressure between the dust collection chamber and the purified gas chamber, and correcting the threshold value of the electrical resistance or current value (a value indicating that the metal filter needs replacing) based on the detected differential pressure, it becomes possible to more accurately diagnose the deterioration (replacement time) of the metal filter by taking into account the differential pressure, i.e., the degree of clogging of the metal filter.

[0025] Furthermore, by transmitting the electrical characteristics (electrical resistance or current) of the metal filter via the internet to a diagnostic device installed in a remote location, the deterioration of the metal filter can be diagnosed remotely online. [Brief explanation of the drawing]

[0026] [Figure 1] This is a longitudinal cross-sectional view showing the state of a dust collector equipped with a metal filter degradation diagnosis system according to the present invention during normal operation (dust collection). [Figure 2] This is an enlarged detailed cross-sectional view of section A in Figure 1. [Figure 3] This is a longitudinal cross-sectional view showing the state of a dust collector equipped with a metal filter degradation diagnosis system according to the present invention during backwashing. [Figure 4] This flowchart shows the processing procedure for the metal filter degradation diagnosis method according to the present invention. [Figure 5] This is a time chart showing the changes in electrical resistance and differential pressure over time in the metal filter degradation diagnosis method (Pattern 1) according to the present invention. [Figure 6] This is a time chart showing the changes over time in electrical resistance and differential pressure in the metal filter degradation diagnosis method (Pattern 2) according to the present invention. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0028] [Dust collector] First, the configuration of the dust collector according to this embodiment will be described below based on Figures 1 to 3.

[0029] Figure 1 is a longitudinal cross-sectional view showing the state of a dust collector equipped with a metal filter deterioration diagnosis system according to the present invention during normal operation (dust collection), Figure 2 is an enlarged detailed cross-sectional view of part A in Figure 1, and Figure 3 is a longitudinal cross-sectional view showing the state of the dust collector during backwashing.

[0030] The dust collector 1 according to this embodiment is equipped with a sealed container-shaped main body (casing) 2, and the inside of this main body 2 is divided into a lower dust collection chamber S1 and an upper purified gas chamber S2 by a horizontal partition wall 3. The lower part of the main body 2 is funnel-shaped, tapering downwards, and a rotary valve 4 is provided at the foreign matter discharge port 2a that opens at its lower end. A gas inlet pipe 5 is connected to the side of the main body 2 at an intermediate height position. One end of this gas inlet pipe 5 is connected to a blast furnace, electric furnace, waste treatment furnace, etc. (not shown) that discharges gas, and the other end is connected to the main body 2 of the dust collector 1 and opens into the dust collection chamber S1 inside the main body 2.

[0031] Furthermore, the dust collection chamber S1 within the main body 2 houses multiple bottomed cylindrical (bag-shaped) metal filters 6 with their lower ends closed. Each metal filter 6 is suspended vertically, with its upper end supported by a partition wall 3. Inside, as shown in Figure 2, a cylindrical frame-shaped (cage-shaped) retainer 7 is incorporated from above to maintain the shape of the metal filter 6. The metal filters 6 are manufactured by embedding metal fibers (short fibers), such as stainless steel (SUS), titanium, or aluminum, into a base material such as nylon felt or polyester felt using needle punching. The retainer 7 is made of a conductive metal such as stainless steel (SUS), iron, or aluminum.

[0032] On the other hand, a gas outlet pipe 8 is connected to the side of the purified gas chamber S2 formed in the upper part of the main body 2. One end of this gas outlet pipe 8 opens into the purified gas chamber S2, and the other end is connected to a suction fan 9.

[0033] Incidentally, the dust collector 1 according to this embodiment is provided with a backwashing device 10 for removing foreign matter such as dust adhering to the outer surface of each metal filter 6 by using high-pressure compressed air. This backwashing device 10 consists of a compressed air supply source 11 such as a compressor installed outside the main body 2 and an injector pipe 12 extending from the compressed air supply source 11.

[0034] The injector pipe 12 is introduced into a purified gas chamber S2 formed in the upper part of the main body 2 and extends horizontally within the purified gas chamber S2. An on / off valve 13 is provided between the main body 2 and the compressed air supply source 11 of the injector pipe 12. Air nozzles 14 are attached to multiple locations on the portion of the injector pipe 12 inserted into the main body 2 (positions facing the upper end opening 6a of each metal filter 6), and these nozzles open toward the upper end opening 6a of each metal filter 6. In this embodiment, the injector pipe 12 is made of SGP pipe (carbon steel pipe for piping), SUS pipe (stainless steel pipe), etc.

[0035] Furthermore, the dust collector 1 according to this embodiment is equipped with a deterioration diagnosis system 20 for diagnosing the deterioration of the metal filter 6. This deterioration diagnosis system 20 energizes the metal filter 6 to detect its electrical characteristic value (electrical resistance value in this embodiment) and diagnoses the deterioration of the metal filter 6 based on the detected electrical characteristic value (electrical resistance value), and is configured as follows. Note that the current value can be used instead of the electrical resistance value as the electrical characteristic value of the metal filter 6, but the electrical resistance value and the current value are inversely proportional.

[0036] In other words, the deterioration diagnosis system 20 includes a power supply device (power supply means) 21 that energizes the metal filter 6, a resistance measuring instrument (electrical characteristic value detection means) 22 that detects the electrical resistance value of the metal filter 6 by energizing the metal filter 6, a pressure gauge 23 that detects the pressure of the gas flowing into the metal filter 6 (internal pressure of the dust collection chamber S1), a pressure gauge 24 that measures the pressure of the gas flowing out of the metal filter 6 (internal pressure of the purified gas chamber S2), and a differential pressure gauge 25 that detects the difference in pressure (differential pressure) detected by both pressure gauges 23 and 24. The system includes a transmitter (transmitting means) 30 that transmits the electrical resistance value detected by the resistance measuring instrument 22 and the differential pressure detected by the differential pressure gauge 25 as signals, a receiver (receiving means) 40 that receives the electrical resistance value signal and differential pressure signal transmitted from the transmitter 30, an internet line 50 provided between the transmitter 30 and the receiver 40, and a deterioration diagnosis device (deterioration diagnosis means) 60 that diagnoses the deterioration of the metal filter 6 based on the electrical resistance value signal and differential pressure signal received by the receiver 40.

[0037] As shown in Figure 2, the power supply line 26 extending from the power supply unit 21 is inserted from above into the metal filter 6 and retainer 7. A weight 27 attached to the tip (lower end) of the power supply line 26 is in contact with the lower end of the retainer 7. Since the weight 27 is made of a conductive metal such as iron, when the weight 27 comes into contact with the retainer 7, which is also made of a conductive metal, the weight 27 and the retainer 7 become electrically conductive, and the retainer 7 and the power supply unit 21 are electrically connected via the power supply line 26. The retainer 7 is also grounded via an earth wire 28, and the resistance meter 22 is connected between the earth wire 28 and the power supply line 26. The resistance meter 22 and the differential pressure gauge 23 are electrically connected to the transmitter 30, as shown by the dashed line in Figure 1. Alternatively, the weight 27 may be made of a magnet and magnetically attracted to the retainer 7.

[0038] In this embodiment, the dust collector 1 is equipped with a thermometer 29 for detecting the temperature of the gas flowing through the gas inlet pipe 5. This thermometer 29 and the compressed air supply source 11 of the backwashing device 10 are electrically connected to a transmitter 30, as shown by the dashed line in Figure 1. The gas temperature signal detected by the thermometer 29 and the drive / stop signal of the compressed air supply source 11 are transmitted from the transmitter 30 to the receiver 40 via the internet line 50. In this embodiment, a thermocouple is used for the thermometer 29.

[0039] The deterioration diagnosis device 60 includes a CPU 61 that diagnoses the deterioration of the metal filter 6 based on the electrical resistance value and differential pressure of the metal filter 6 transmitted from the transmitter 30 via the internet line 50 and receiver 40; a storage unit 62 such as ROM or RAM that stores programs executed by the CPU 61, electrical resistance value data, and differential pressure data in chronological order; a timer 63 that measures the elapsed time since the end of backwashing; a counter 64 that counts the number of backwashing cycles; and a display (notification means) 65 that displays information to prompt the replacement of the metal filter 6 (such as an alarm, an indication of when it is time to replace, or a flashing warning light).

[0040] [Method for diagnosing deterioration of metal filters] Next, a method for diagnosing the deterioration of the metal filter 6 using the deterioration diagnosis system 20 installed in the dust collector 1 configured as described above will be explained below with reference to Figures 4 to 6.

[0041] Figure 4 is a flowchart showing the processing procedure for the metal filter degradation diagnosis method according to the present invention, Figure 5 is a time chart showing the changes in electrical resistance and differential pressure over time in the metal filter degradation diagnosis method (Pattern 1) according to the present invention, and Figure 6 is a time chart showing the changes in electrical resistance and differential pressure over time in the same degradation diagnosis method (Pattern 2).

[0042] The present invention provides a method for diagnosing the deterioration of a metal filter 6, characterized by detecting the electrical characteristic value (electrical resistance value or current value) of the metal filter 6 and diagnosing the deterioration of the metal filter 6 based on the detected electrical characteristic value. Specifically, in this embodiment, if the electrical resistance value of the metal filter 6 increases beyond a predetermined threshold, it is diagnosed that the metal filter 6 is due for replacement. If the current value is used as the electrical characteristic value of the metal filter 6, it is diagnosed that the metal filter 6 is due for replacement if the current value decreases beyond a predetermined threshold.

[0043] Here, the threshold value for electrical resistance is corrected based on the differential pressure detected by the differential pressure gauge 25. Specifically, the larger the differential pressure, the more easily the metal filter 6 is likely to clog, making it more difficult for current to flow and increasing the electrical resistance. Therefore, by raising the threshold value for electrical resistance, it becomes possible to diagnose the deterioration of the metal filter 6, taking into account the increase in electrical resistance due to clogging of the metal filter 6. Similarly, the smaller the differential pressure, the less likely it is that the metal filter 6 is clogged, making it easier for current to flow and resulting in a smaller electrical resistance. Therefore, by lowering the threshold value for electrical resistance, it becomes possible to diagnose the deterioration of the metal filter 6 with high accuracy. Furthermore, if the current value is selected as the electrical characteristic value, the larger the differential pressure, the more difficult it is for current to flow, so lowering the threshold value for current is possible. Conversely, the smaller the differential pressure, the easier it is for current to flow, so raising the threshold value for current is possible, thereby enabling a highly accurate diagnosis of the deterioration of the metal filter 6.

[0044] In this embodiment, if the differential pressure increases beyond a predetermined threshold, the backwashing device 10 performs backwashing by injecting compressed air into the metal filter 6. The elapsed time since backwashing is measured by a timer 63 (see Figure 1) provided in the deterioration diagnosis device 60. After a predetermined time has elapsed since the backwashing is completed, the electrical resistance value of the metal filter 6 is detected by a resistance meter 22, and the deterioration of the metal filter 6 is diagnosed based on the detected electrical resistance value. In this embodiment, the number of backwashes is counted by a counter 64 (see Figure 1) provided in the deterioration diagnosis device 60. When the counted number of backwashes reaches a predetermined value, or when the electrical resistance value of the metal filter 6 exceeds a predetermined threshold, the CPU 61 of the deterioration diagnosis device 60 shown in Figure 1 diagnoses that the metal filter 6 is due for replacement and displays the replacement time on the display 65. This allows the user to know in advance when the metal filter 6 needs to be replaced, eliminating the need to replace the metal filter 6 after it has torn or been damaged, and avoiding the need to shut down the dust collector 1 to perform unexpected repairs on the metal filter 6.

[0045] The following describes in detail the method for diagnosing the deterioration of the metal filter 6 according to the present invention.

[0046] When the dust collector 1 shown in Figure 1 is in normal operation, the rotary valve 4 located at the lower end of the main body 2 is closed, as shown in Figure 1, and the backwashing device 10 is stopped (non-operating). When the suction fan 9 is driven to rotate in this state, both the dust collection chamber S1 and the purified gas chamber S2 inside the main body 2 become negative pressure, and gas discharged from a waste treatment furnace (not shown) is drawn in by this negative pressure and flows into the dust collection chamber S1 inside the main body 2 from the gas inlet pipe 5, as indicated by the arrow in Figure 1.

[0047] As described above, the gas flowing into the dust collection chamber S2 passes through multiple metal filters 6, and foreign matter such as dust contained in it is collected by each metal filter 6 and adheres to the outer surface of each metal filter 6. Then, the gas, purified by the removal of foreign matter by the metal filters 6, is discharged into the purified gas chamber S2 from the upper end opening 6a of each metal filter 6, as shown by the arrows in Figure 1, flows out of the main body 2 through the gas outlet pipe 8, is sucked in by the suction fan 9 and sent to a processing device (not shown).

[0048] As the above dust collection process is repeated, foreign matter such as dust gradually adheres to and accumulates on the outer surface of each metal filter 6, and the metal fibers that make up each metal filter 6 deteriorate (for example, the thickness of the fibers becomes thinner).

[0049] Here, the factors that cause deterioration of the metal filter 6 include clogging due to the adhesion of foreign matter to the metal filter 6 and deterioration of the metal fibers that make up the metal filter 6 themselves. The degree of clogging of the metal filter 6 is detected by the differential pressure (pressure difference between the inside and outside of the metal filter 6) detected by the differential pressure gauge 25, and if this differential pressure increases beyond a predetermined threshold, the metal filter 6 is backwashed by the backwashing device 10 shown in Figure 1.

[0050] Furthermore, the electrical resistance of the metal filter 6 is detected by the resistance meter 22 (see Figure 1), and if the detected electrical resistance increases beyond a predetermined threshold, the CPU 61 in the degradation diagnostic device 60 shown in Figure 1 displays a message on the display 65 prompting the replacement of the metal filter 6. Note that the degradation diagnosis is performed only on specific samples of the metal filter 6, not on all of them.

[0051] Incidentally, in diagnosing the deterioration of the metal filter 6, there are two timings for prompting the replacement of the metal filter 6: when the electrical resistance value of the metal filter 6 increases beyond a predetermined threshold before the number of backwashes reaches a predetermined value (for example, 5 times) (Pattern 1), and when the number of backwashes reaches a predetermined value before the electrical resistance value of the metal filter 6 reaches a predetermined threshold (Pattern 2).

[0052] Here, the method for diagnosing the deterioration of the metal filter 6 in Pattern 1 will be explained below based on Figures 4 and 5.

[0053] When the deterioration diagnosis of the metal filter 6 is started, initial settings are made, the counter value (number of backwashes) N of the counter 64 is reset (N=0), and the elapsed time Δt since the backwash is reset (Δt=0) (step S1 in Figure 4).

[0054] Next, the differential pressure Δp is detected by the differential pressure gauge 25 (step S2), and the detected differential pressure Δp is set to a predetermined threshold Δp th The CPU 61 of the degradation diagnostic device 60 determines whether or not the condition has been reached (step S3).

[0055] Figure 5 shows the temporal changes in electrical resistance r and differential pressure Δp in pattern 1. As shown in the figure, the electrical resistance r and differential pressure Δp gradually increase with the passage of time t as the metal filter 6 deteriorates. As shown in Figure 5, at time t1, the differential pressure Δp reaches a predetermined threshold Δp th If the threshold is reached (Step S3: Yes), the metal filter 6 is backwashed by the backwashing device 10. This backwashing is performed on all metal filters 6. Also, when the differential pressure Δp reaches a predetermined threshold Δp th If the value has not been reached (Step S3: No), the detection of the differential pressure Δp continues (Step S3 → Step S2).

[0056] The operation of the dust collector 1 during the backwashing of the metal filter 6 will be explained below with reference to Figure 3.

[0057] The CPU 61 of the deterioration diagnostic device 60 determines when the differential pressure Δp is a predetermined threshold Δp thWhen this condition is reached, the backwashing device 10 is activated to backwash the metal filter 6. Specifically, when a compressed air supply source 11, such as a compressor (not shown), is activated and the on / off valve 13 is opened, high-pressure compressed air discharged from the compressed air supply source 11 flows through the injector pipe 12 in the direction of the arrows shown in the figure, and is instantaneously injected from each air nozzle 14 toward the upper end opening 6a of each metal filter 6. As a result, foreign matter adhering to the outer surface of each metal filter 6 is blown off and removed by the compressed air. Then, the foreign matter such as dust blown off from the outer surface of each metal filter 6 falls into the dust collection chamber S2 as shown by the arrows in Figure 3, is collected at the bottom of the main body 2, and is discharged outside the main body 2 through the foreign matter discharge port 2a when the rotary valve 4 opens and is recovered.

[0058] As a result of the backwashing described above, the purification performance of the metal filter 6 is restored to some extent. Therefore, the electrical resistance value r and differential pressure Δp of the metal filter decrease to r1 and Δp1, respectively, at time t1. However, these values ​​r1 and Δp1 are somewhat larger than the initial values ​​r0 and Δp0 (r1>r0, Δp1>Δp0).

[0059] When the above-mentioned backwashing is completed, the timer 63 in the deterioration diagnostic device 60 counts the elapsed time Δt since the end of backwashing (Δt=Δt+1), and the counter 64 counts the number of backwashing cycles N (N=N+1) (step S5). Then, the CPU 61 determines whether the elapsed time Δt has reached a predetermined value Δt1 (Δt=Δt1?) (step S6). If the elapsed time Δt has reached the predetermined value Δt1 (step S6: Yes), the CPU 61 starts detecting the electrical resistance value r of the metal filter 6 using the resistance meter 22 (step S7), and sets the threshold value r of the electrical resistance value r th This is corrected as described above based on the current differential pressure Δp (step S8). Then, the elapsed time Δt measured by the timer 63 is reset (Δt=0) (step S9).

[0060] Next, the CPU 61 determines that the current electrical resistance value r is a predetermined threshold r th Whether it exceeded or not (r>r thDetermine (?)(Step S10). In the case of Pattern 1 shown in FIG. 5, since the electrical resistance value r does not exceed the threshold value r until the time t2 for performing the second (N = 2) backwash (r < r th ), the determination result in Step S10 is No, and the process proceeds to Step S11.

[0061] In Step S11, it is determined whether the number of backwashes N has reached a predetermined number N0 (in this embodiment, N0 = 5) (N > N0?). In this example, since only one backwash has been performed (N = 1), the determination result in Step S11 is No, and the process proceeds to Step S2 (Step S11 → Step S2). The series of processes described above (Steps S2 to Step S11) are repeated until the number of backwashes N reaches the predetermined value N0 (= 5). However, in Pattern 1, as shown in FIG. 5, after the second backwash is performed at time t2, at time t x the electrical resistance value r of the metal filter 6 reaches a predetermined threshold value th . Therefore, at this point, the determination result in Step S10 becomes Yes, and a display prompting replacement of the metal filter 6 is displayed on the display 65 of the deterioration diagnosis device 60 (Step S12), and a series of deterioration diagnoses for the metal filter 6 ends (Step S13).

[0062] On the other hand, in the case of Pattern 2 shown in FIG. 6, when the number of backwashes N reaches the predetermined number N (= 5) (Step S11: Yes), even if the electrical resistance r of the metal filter 6 does not exceed the predetermined threshold value r th (r < r th ), the CPU 61 displays a message prompting replacement of the metal filter 6 on the display 65 (Step S12), and a series of deterioration diagnoses for the metal filter 6 ends (Step S13).

[0063] In this embodiment, even if the electrical resistance value r of the metal filter 6 has not reached the predetermined threshold value r th , the number of backwashes N prompting replacement of the metal filter 6 is set to 5, but this number can be set arbitrarily. ​​

[0064] As described above, the deterioration diagnosis method for the metal filter 6 performed using the deterioration diagnosis system according to this embodiment involves energizing the metal filter 6 and detecting its electrical characteristics (electrical resistance). Therefore, the deterioration of the metal fibers themselves (including the deterioration of the metal filter 6, such as an increase in electrical resistance due to the thinning of the metal fibers (decrease in current)) can be accurately diagnosed by the electrical characteristics (electrical resistance) of the metal filter 6. Furthermore, since it is possible to energize the metal filter 6 and detect its electrical characteristics (electrical resistance) even when the dust collector 1 is stopped, the deterioration of the metal filter 6 can be diagnosed regardless of whether the dust collector 1 is running or stopped.

[0065] Furthermore, the differential pressure between the dust collection chamber S1 and the purified gas chamber S2 of the dust collector 1 (the differential pressure inside and outside the metal filter 6) is detected, and the electrical resistance value (a value indicating that the metal filter 6 is due for replacement) is corrected based on the detected differential pressure. This allows for a more accurate diagnosis of the deterioration (time for replacement) of the metal filter 6, taking into account the differential pressure, i.e., the degree of clogging of the metal filter 6.

[0066] Furthermore, since the electrical characteristics (electrical resistance) of the metal filter 6 can be transmitted via the internet connection 50 to a degradation diagnosis device 60 installed in a remote location, the degradation of the metal filter 6 can be diagnosed remotely online, which is another benefit.

[0067] Furthermore, in this embodiment, electrical resistance data and differential pressure data transmitted from the transmitter 30 to the deterioration diagnostic device 60 via the internet line 50 and receiver 40 are stored chronologically in the storage unit 62. This allows for the chronological understanding of the deterioration of the metal filter 6 by comparing it with past data. By accumulating long-term data, preventative safety can be enhanced by linking it with the operating status of the entire system, including the equipment before and after the dust collector 1.

[0068] In this embodiment, the deterioration of the metal filter 6 is diagnosed remotely online, but the deterioration of the metal filter 6 may also be diagnosed offline at the site where the dust collector 1 is installed.

[0069] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical idea described in the claims, specification, and drawings. [Explanation of symbols]

[0070] 1. Dust collector 2 Main unit 3 Bulkhead 6. Metal filter 10 Backwash device (backwash means) 20. Deterioration Diagnosis System 21 Power supply device (power means) 22. Resistance measuring instrument (means for detecting electrical characteristics) 25. Differential pressure gauge (differential pressure detection means) 30 Transmitter (transmission means) 40 Receiver (receiving means) 50 Internet connection 60. Deterioration diagnostic device (deterioration diagnostic means) 61 CPU 62 Memory section 63 Timer 64 counters 65. Display (Notification method) Δp differential pressure r Electrical resistance value S1 Dust Collection Room S2 Gas Purification Chamber

Claims

1. A system for diagnosing the deterioration of a metal filter in a dust collector, which is constructed by dividing the inside of the main body into a dust collection chamber and a purified gas chamber by a partition wall, and attaching a metal filter to the partition wall, A power supply means for supplying current to the metal filter, An electrical characteristic value detection means for detecting the electrical characteristic value of the metal filter, A transmitting means that transmits the electrical characteristic value of the metal filter detected by the electrical characteristic value detection means as a signal, A receiving means for receiving an electrical characteristic value signal transmitted from the transmitting means, A deterioration diagnosis means for diagnosing the deterioration of the metal filter based on the electrical characteristic value signal received by the receiving means, A metal filter degradation diagnosis system characterized by comprising the following features.

2. The metal filter degradation diagnosis system according to claim 1, characterized in that an internet connection is provided between the transmitting means and the receiving means, and the electrical characteristic value signal transmitted from the transmitting means is transmitted to the receiving means via the internet connection.

3. The metal filter deterioration diagnosis system according to claim 1, further comprising a differential pressure detection means for detecting the differential pressure between the dust collection chamber and the purified gas chamber.

4. The metal filter deterioration diagnosis system according to claim 3, further comprising a backwashing means for injecting compressed air into the metal filter when the differential pressure detected by the differential pressure detection means increases beyond a predetermined threshold.

5. The metal filter deterioration diagnosis system according to claim 1, characterized in that the deterioration diagnosis means includes a notification means for notifying the time when the metal filter should be replaced.

6. The deterioration diagnostic means includes a timer that measures the time elapsed since the metal filter was backwashed by the backwashing means, A counter for counting the number of backwashes, The metal filter degradation diagnosis system according to claim 4, characterized by comprising the following:

7. The aforementioned electrical characteristic value is either an electrical resistance value or a current value, The metal filter deterioration diagnosis system according to claim 1, characterized in that the deterioration diagnosis means diagnoses that the metal filter is due for replacement when the electrical resistance value increases beyond a predetermined threshold or when the current value decreases beyond a predetermined threshold.

8. The system comprises a differential pressure detection means for detecting the differential pressure between the dust collection chamber and the purifying gas chamber, The deterioration diagnosis means is characterized in that it corrects the threshold value of the electrical resistance value or the current value based on the differential pressure detected by the differential pressure detection means, as described in claim 7, for a metal filter deterioration diagnosis system.

9. The deterioration diagnostic means raises the threshold value of the electrical resistance value or lowers the threshold value of the current value as the differential pressure increases. The metal filter degradation diagnosis system according to claim 8, characterized in that the smaller the differential pressure, the lower the threshold value of the electrical resistance value or the higher the threshold value of the current value.

10. The metal filter deterioration diagnosis system according to claim 4, characterized in that the deterioration diagnosis means diagnoses the deterioration of the metal filter based on the electrical characteristic values ​​of the metal filter after a predetermined time has elapsed since the backwashing.

11. The electrical characteristic value is an electrical resistance value or a current value, The deterioration diagnosis means counts the number of backwashes and diagnoses that the metal filter is due for replacement when the counted number reaches a predetermined value, or when the electrical resistance or current value of the metal filter exceeds a predetermined threshold, as described in claim 4.

12. A method for diagnosing the deterioration of a metal filter using the metal filter deterioration diagnosis system described in any one of claims 1 to 11, A method for diagnosing the deterioration of a metal filter, characterized by detecting the electrical characteristic value of the metal filter using the electrical characteristic value detection means, and diagnosing the deterioration of the metal filter using the deterioration diagnosis means based on the electrical characteristic value signal received by the receiving means.

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