Centrifuge monitoring and control system

Abstract

The present invention aims to provide a monitoring and control system for a centrifuge that can quickly detect a decrease in separation performance by detecting a sudden increase in solid content, thereby preventing equipment malfunction. The system comprises a centrifuge 2 in which a liquid to be treated flows in from an inlet 20 and is introduced into the interior, a separation plate is rotated by an electric motor 21, the introduced liquid to be treated is separated into sludge and separated liquid, and the separated liquid is discharged to the outside from a separated liquid discharge section 22, the separated liquid discharged from the separated liquid discharge section 22 is introduced into a separated liquid line 3 equipped with at least a back pressure valve 31 and a pressure gauge PG, a portion of the separated liquid introduced into the separated liquid line 3 is guided to a detection line 4 equipped with at least a detection filtering unit 40, a constant flow valve 41 and a flow meter 42 by adjusting the back pressure valve 31, and when it is determined that the value measured by the flow meter 42, which measures the flow rate adjusted by the constant flow valve 41 provided downstream of the detection filtering unit 40, is below a predetermined flow rate lower limit threshold, the electric motor 21 is stopped.

Description

[Technical Field]

[0001] The present invention relates to a monitoring and control system for a centrifuge, and more particularly to a monitoring and control system for a centrifuge that can quickly detect a decrease in separation performance and prevent equipment malfunctions by detecting a sudden increase in solid content. [Background technology]

[0002] In order to reduce health impacts and improve air quality, from January 1, 2020, it will be mandatory for ships in all ocean areas around the world to use fuel oil with a sulfur content of 0.5% by mass or less.

[0003] Very Low Sulfur Fuel Oil (VLSFO) is the fuel that meets these regulations. VLSFO is primarily classified into paraffinic distillate grade VLSFO-DM and aromatic residual oil grade VLSFO-RM, depending on the fuel oil manufacturing process. VLSFO has a lower kinematic viscosity and density than HSFO (High Sulphur-C heavy oil) and a wider range of viscosity than conventional fuel oils, making it useful as a fuel oil that complies with regulations.

[0004] However, VLSFO has large variations in fuel oil properties due to bunker purging (bunkering ships), and in particular, problems such as sludge formation when different fuel oils are mixed, as well as problems with low-temperature fluidity such as blending stability, storage stability, and waxing at low temperatures.

[0005] Furthermore, when different VLSFOs, such as distillate and residual oils, are mixed, there is a risk of large amounts of sludge (solids) being generated.

[0006] Furthermore, not only in marine fuel oil but also in lubricating oil, there is a possibility that the separation performance of the centrifuge will be reduced due to the large amount of sludge generated.

[0007] Patent Document 1 discloses a method for determining the level of contamination inside the drum of a centrifuge, in which a value (theoretical value) for the maximum internal volume of the drum is compared with a measured value (calculated value) of the drum's currently available drum capacity, and a technology is disclosed in which the level of contamination is determined and a warning is issued or the drum is stopped in an emergency. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2023-550810 [Patent Document 2] Patent No. 6931097 Summary of the Invention [Problem to be solved by the invention]

[0009] In a disc-type centrifuge, solids are stored inside the rotor and are automatically discharged at set timer intervals. However, if the solid content in the treatment liquid being supplied suddenly increases, the inside of the rotor of the centrifuge can be filled with sludge (solids) beyond its capacity, resulting in poor separation, the accumulated sludge flowing out to the clean side outlet, and only a portion of the sludge being discharged from the rotor, leaving some behind (segregation), which can lead to an imbalance that reduces the separation performance of the centrifuge or cause equipment malfunctions.

[0010] To address this issue, the technology of Patent Document 1 cannot avoid a decline in the separation performance of the centrifuge due to imbalance and malfunction of the equipment if sludge or the like segregates on the separator (separation plate), even if the volume of sludge relative to the total internal volume is reduced.

[0011] The inventors have developed a new centrifuge monitoring and control system that detects a sudden increase in solid content in the centrifuge outlet, thereby quickly detecting a decline in separation performance, preventing equipment malfunctions, and safely shutting down operation.

[0012] Therefore, an object of the present invention is to provide a monitoring and control system for a centrifuge that can quickly detect a decline in separation performance and prevent equipment malfunctions by detecting a sudden increase in solid content.

[0013] Further objects of the present invention will become apparent from the following description. [Means for solving the problem]

[0014] The above problems are solved by the following inventions.

[0015] 1. The liquid to be treated is introduced into the centrifuge (2) through the inlet (20), The centrifugal separator (2) has a structure in which a separation plate (200) of the centrifugal separator (2) is rotated by an electric motor (21), the introduced liquid to be treated is separated into sludge and separated liquid, the sludge is discharged from a sludge discharge section (23), and the separated liquid is discharged to the outside from a separated liquid discharge section (22). The separated liquid discharged from the separated liquid discharge part (22) is introduced into a separated liquid line (3) equipped with at least a back pressure valve (31) and a pressure gauge (PG), a back pressure valve (31) for adjusting a part of the separated liquid introduced into the separated liquid line (3) to a detection line (4) including at least a detection filtering unit (40), a constant flow valve (41), and a flow meter (42); the control unit (5) is connected to at least the flow meter (42) and the electric motor (21); the control unit (5) stops the motor (21) when it determines that a value measured by the flow meter (42), which measures the flow rate adjusted by the constant flow valve (41) provided downstream of the detection filtering unit (40), is equal to or less than a predetermined flow rate lower limit threshold. 2. The control unit (5) determines whether a state in which the measurement value of the flow meter (42) is equal to or less than a predetermined flow rate lower limit threshold continues for a predetermined detection time, 2. The monitoring and control system for a centrifuge according to claim 1, wherein the electric motor (21) is stopped when it is determined that the predetermined detection time has continued. 3. The liquid to be treated is introduced into the centrifuge (2) through the inlet (20), The centrifugal separator (2) has a structure in which a separation plate (200) of the centrifugal separator (2) is rotated by an electric motor (21), the introduced liquid to be treated is separated into sludge and separated liquid, the sludge is discharged from a sludge discharge section (23), and the separated liquid is discharged to the outside from a separated liquid discharge section (22). The separated liquid discharged from the separated liquid discharge part (22) is introduced into a separated liquid line (3) equipped with at least a back pressure valve (31) and a pressure gauge (PG), The system has a structure in which a part of the separated liquid introduced into the separated liquid line (3) is guided to a detection line (4) equipped with at least a detection filtering unit (40) and a constant flow valve (41) by adjusting the back pressure valve (31), The detection filtering unit (40) is provided with a detection filter (40B), and a pressure gauge P1 is provided upstream of the detection filter (40B) and a pressure gauge P2 is provided downstream of the detection filter (40B), the control unit (5) is connected to at least the pressure gauge P1, the pressure gauge P2, and the electric motor (21); The control unit (5) calculates a differential pressure between the pressure measured by the pressure gauge P1 and the pressure measured by the pressure gauge P2, and determines whether the calculated differential pressure is equal to or less than a predetermined upper limit threshold value of the differential pressure, The monitoring and control system for a centrifuge is characterized in that, when it is determined that the calculated differential pressure is equal to or greater than a predetermined differential pressure upper limit threshold, the electric motor (21) is stopped. 4. The control unit (5) determines whether the calculated differential pressure is equal to or greater than a predetermined differential pressure upper limit threshold value for a predetermined detection time. 4. The monitoring and control system for a centrifuge according to claim 3, wherein the electric motor (21) is stopped when it is determined that the condition has continued for a predetermined detection time. 5. 5. The monitoring and control system for a centrifuge according to claim 3 or 4, characterized in that a catch tank (45) is provided downstream of the constant flow valve (41), and the catch tank (45) is provided with an atmospheric vent (46). 6. an automatic three-way valve (1) is provided upstream of the introduction section (20) of the centrifuge (2) for the liquid to be treated, and the automatic three-way valve (1) is capable of switching the flow of the liquid to be treated to a flow direction toward the centrifuge (2) or a flow direction toward a storage tank for the liquid to be treated; The control unit (5) is connected to the three-way automatic valve (1), 5. The monitoring and control system for a centrifuge according to any one of 1 to 4, characterized in that the electric motor (21) is stopped and the flow path direction of the three-way automatic valve (1) on the centrifuge (2) side is switched to the flow path direction on the storage tank side of the liquid to be treated. 7. 5. The monitoring and control system for a centrifuge according to any one of 1 to 4, wherein the detection filtering unit (40) is composed of a filter housing (40A) and a detection filter (40B) housed in the housing. 8. 5. The monitoring and control system for a centrifuge according to any one of 1 to 4, wherein a shutoff valve (43) is provided between the detection filtering unit (40) and the constant flow valve (41). 9. 8. The monitoring and control system for a centrifuge according to claim 7, characterized in that a compressed air introduction line (6) is connected to the detection line (4) downstream of the detection filtering unit (40), and compressed air introduced via the compressed air introduction line (6) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to air wash the detection filter (40B) in the detection filtering unit (40). 10. The monitoring and control system for a centrifuge according to item 7, characterized in that a cleaning agent introduction line (7) is connected to the detection line (4) downstream of the detection filtering unit (40), and the cleaning agent introduced via the cleaning agent introduction line (7) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to clean the detection filter (40B) in the detection filtering unit (40). 11. The monitoring and control system for a centrifuge according to claim 10, further comprising a flow path for introducing the cleaning agent used to clean the detection filter (40B) into the inlet (20) of the centrifuge (2). 12. A compressed air introduction line (6) and a cleaning agent introduction line (7) are connected to the detection line (4) downstream of the detection filtering unit (40); The compressed air introduced through the compressed air introduction line (6) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to air-clean the detection filter (40B) in the detection filtering unit (40), and 8. The monitoring and control system for a centrifuge according to claim 7, characterized in that the cleaning agent introduced through the cleaning agent introduction line (7) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to clean the detection filter (40B) in the detection filtering unit (40). 13. 13. The monitoring and control system for a centrifuge according to claim 12, further comprising a flow path for introducing compressed air or a cleaning agent after cleaning the detection filter (40B) into the inlet (20) of the centrifuge (2). [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a monitoring and control system for a centrifuge that can quickly detect a decrease in separation performance and prevent equipment malfunctions by detecting a sudden increase in solid content. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram illustrating a first embodiment. [Figure 2] A half-sectional view illustrating an example of the mechanism of a centrifuge. [Figure 3] A half-sectional view illustrating an example of sludge discharge from a centrifuge [Figure 4] A half-sectional view illustrating an example of abnormal sludge deposition in a centrifuge [Figure 5] FIG. 1 is a diagram showing a control flow of the first embodiment. [Figure 6] FIG. 1 is an explanatory diagram showing a filter cleaning mode in the first embodiment; [Figure 7] FIG. 2 is an explanatory diagram illustrating a second embodiment. [Figure 8] FIG. 10 is a diagram showing a control flow of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will now be described.

[0019] FIG. 1 is an explanatory diagram showing a first embodiment of the present invention. Figure 1 shows an example of a flow rate monitoring system that monitors the state of a centrifuge 2, which has a separated liquid line 3 and a detection line 4 branching off from the separated liquid line 3, and which separates the liquid to be treated using a centrifuge.

[0020] In this embodiment, an example is shown in which a liquid to be treated, such as fuel oil or lubricating oil, is separated.

[0021] The three-way automatic valve 1 is configured to be able to switch the flow direction of the inflowing liquid to be treated between the flow direction to the storage tank side of the liquid to be treated (bypass return) and the flow direction to the centrifuge 2. The three-way automatic valve 1 may be any valve that can automatically switch the flow direction using, for example, a solenoid valve, an air valve, or the like, and there are no particular limitations on the operating method. When the three-way automatic valve 1 is switched to the flow path direction toward the centrifuge 2 , the liquid to be treated flows into the centrifuge 2 through the inlet 20 thereof and is introduced into the centrifuge 2 .

[0022] Fig. 2 is a half-sectional view illustrating an example of the mechanism of a centrifuge, Fig. 3 is a half-sectional view illustrating an example of sludge discharge from a centrifuge, and Fig. 4 is a half-sectional view illustrating an example of an abnormal sludge deposition state in a centrifuge. While Figs. 2 to 4, which will be described later, show examples in which a centrifuge separates a liquid to be treated into three types: solids (sludge), heavy liquid, and light liquid, the centrifuge 2 used in this embodiment is only required to be able to separate at least solids (sludge) and separated liquid (light liquid). Therefore, the following description will be given assuming that the centrifuge 2 separates into solids (sludge) and separated liquid (light liquid).

[0023] As shown in FIGS. 1 and 2, in the centrifuge 2, the separation plate 200 of the centrifuge rotates as the electric motor 21 rotates, separating the introduced liquid to be treated into solids (sludge) and separated liquid.

[0024] The separated liquid in the centrifuge 2 is discharged from the separated liquid discharge section 22 to the separated liquid line 3. As shown in Figures 1, 2, and 3, the solid content separated in the centrifuge 2 is stored in the solid content storage section 201 inside the centrifuge 2. At this time, the sludge discharge port 203 is closed. After a predetermined time has elapsed, as shown in Figure 3, the valve body 202 at the bottom of the centrifuge 2 opens downward automatically or manually while the separation plate 200 remains rotating, thereby widening the sludge discharge port 203, and the sludge is discharged outward from the solid content storage section 201 by the action of centrifugal force. The sludge discharged from the sludge discharge port 203 is then discharged to the outside from the sludge discharge section 23.

[0025] 4, when a liquid to be treated containing a high concentration of solids is supplied to the centrifuge 2, the solids reservoir 201 inside the rotor quickly fills with the solids, and the solids reach the outer edge of the separation plates where the liquid is centrifuged. In this case, the separation efficiency may decrease due to turbulence in the flow between the stacked separation plates 200, and the accumulated solids may be eroded in the direction of the fluid flow, causing the solids to flow out into the separation liquid line 3 together with the separation liquid.

[0026] 1, the separated liquid line 3 is equipped with at least a back pressure valve 31 and a pressure gauge PG. When the separated liquid discharged from the separated liquid discharge portion 22 of the centrifuge 2 flows into the separated liquid line 3, the back pressure valve 31 is throttled to create back pressure, and a portion of the separated liquid is guided to the detection line 4. The back pressure of the back pressure valve 31 can be adjusted based on the pressure of the pressure gauge PG.

[0027] The detection line 4 includes at least a detection filtering unit 40, a constant flow valve 41, and a flow meter .

[0028] The detection filtering unit 40 is composed of a filter housing 40A and a detection filter 40B housed in the housing.

[0029] A constant flow valve 41 is provided downstream of the detection filtering unit 40 so that a constant flow rate can be maintained regardless of pressure fluctuations of the separated liquid in the detection line 4 .

[0030] Furthermore, a flow meter 42 is provided between the detection filtering unit 40 and the constant flow valve 41, and it is possible to check whether the constant flow rate is maintained by the constant flow valve 41. In this embodiment, it is preferable to raise the outlet pipe downstream of the constant flow valve of the detection line 4 in a substantially vertical direction. The raised height (head) of the outlet pipe can be determined by taking into consideration the back pressure of the separated liquid indicated by the pressure gauge PG and the pressure loss of the constant flow valve 41.

[0031] In this embodiment, a shutoff valve 43 is preferably provided between the detection filtering unit 40 and the constant flow valve 41. When the separation liquid is being monitored, the shutoff valve 43 is opened, but it is preferable to keep the shutoff valve 43 closed until the housing 40A is filled with the separation liquid that has branched off and flowed into the detection line 4 from the separation liquid line 3. Once the housing 40A is completely filled with the separation liquid, the shutoff valve 43 can be opened to start detection. The shutoff valve 43 also functions during filter cleaning, which will be described later.

[0032] The control unit 5 is configured to acquire the measurement value of the flow meter 42, control the operation of the three-way automatic valve 1 and the electric motor 21 of the centrifugal separator 2, and monitor the flow rate.

[0033] Based on FIG. 5, the control flow of flow rate monitoring will be described with reference to FIG. FIG. 5 is a flowchart showing an example of a control flow for monitoring the flow rate.

[0034] First, the motor is started, and after reaching the rated rotation speed, operation is started (S1).

[0035] Next, the three-way automatic valve 1 is switched to the flow path direction toward the centrifuge 2 (S2). When switched, the liquid to be treated is introduced into the centrifuge 2 and centrifuged. The centrifuged separated liquid 30 flows into the separated liquid line 3 via the separated liquid discharge part 22.

[0036] Next, when the separated liquid 30 flows into the separated liquid line 3, the pressure on the pressure gauge PG rises, and the back pressure valve 31 is adjusted according to the pressure value on the pressure gauge PG (S3).

[0037] Next, by adjusting the back pressure valve 31, a portion 30a of the separated liquid 30 that has flowed into the separated liquid line 3 is branched off and flows into the detection line 4. As a result of this inflow, the separated liquid is introduced into the filter housing 40A, and it is confirmed that the detection start delay timer has elapsed (S4), and flow rate monitoring is started.

[0038] Here, by making it possible to set a detection start delay timer (set unit: sec) in the control unit 5 from when the three-way automatic valve 1 is switched to the centrifuge 2 side until monitoring starts, it is possible to prevent false alarms from occurring when "liquid flow starts → immediate alarm." Immediately after the start of liquid flow, the filter housing 40A is not filled with separated liquid, so the flow rate is not stable and a false alarm occurs, so this is useful from the viewpoint of preventing this.

[0039] Next, in the flow rate monitoring, the control unit 5 presets a predetermined flow rate lower limit threshold and a predetermined detection time, acquires the measurement value of the flow meter 42, and determines whether the measurement value remains below the predetermined flow rate lower limit threshold for a predetermined detection time or longer (S5).

[0040] If the flow rate does not continue (NO in S5), the flow rate monitoring in S5 is continued and repeated.

[0041] On the other hand, if the condition continues (YES in S5), it is considered as abnormal sludge deposition and an alarm is issued (S6).

[0042] When abnormally precipitated sludge (solids) flows out to the separated liquid side, it accumulates on the detection filter 40B inside the filter housing 40A, causing the flow rate of the flow meter 42 downstream of the detection filtering unit 40 to decrease. Unless this is a false detection, the flow rate will remain below the lower limit threshold for a specified detection time or longer, and abnormal sludge deposition can be detected based on the measurement value of the flow meter 42. The detection filter 40B can be made of metal media such as sintered metal, laminated sintered metal, wedge wire screen, notch wire, spring filter, or ceramic filter, and the filter can be cleaned by backflowing compressed air.

[0043] Next, at the same time as the alarm is issued, the three-way automatic valve 1 is switched to the flow path direction toward the fuel oil storage tank, stopping the supply of the liquid to be treated to the centrifuge 2, and at the same time, the power supply to the electric motor 21 of the centrifuge 2 is cut off (S7), bringing the centrifuge 2 to an emergency stop.

[0044] By controlling in this way, it is possible to quickly detect a decrease in the separation performance of the centrifugal separator 2, and as a result, it is possible to quickly recover from the decrease in separation performance and prevent malfunctions of the equipment.

[0045] In the above explanation, in the judgment of S5, it is judged whether the state in which the measurement value is equal to or less than the predetermined flow rate lower limit threshold continues for a predetermined detection time or more, but from the viewpoint of quickly detecting a decrease in separation performance and preventing malfunctions of the equipment, it is not necessary to judge whether the state continues for a predetermined detection time or more, because the purpose of the judgment based on the detection time is to prevent false detection.

[0046] Fig. 6 is a diagram for explaining an example of cleaning of the detection filter in the flow rate monitoring system of Fig. 1. In Fig. 6, the same reference numerals as in Fig. 1 denote the same parts, and therefore the description thereof will be omitted.

[0047] FIG. 6 shows an example in which a compressed air introduction line 6 and a cleaning agent introduction line 7 are formed in the flow rate monitoring system of FIG.

[0048] First, cleaning via the compressed air introduction line 6 will be described. In this embodiment, compressed air is introduced from the rear side of the detection filtering unit 40 through the compressed air introduction line 6 to clean the filter, and after the filter has been cleaned, it can be introduced from the introduction section 20 side of the centrifuge 2. In this embodiment, the timing for cleaning the detection filter 40B is preferably immediately after the solid content discharge process of the centrifuge 2 shown in Fig. 3. Periodic filter cleaning can maintain monitoring accuracy.

[0049] The compressed air from a compressor (not shown) that generates the compressed air only needs to have a pressure sufficient to clean the filter. As shown in Fig. 6, by opening shutoff valve 61, opening shutoff valve 62, and further closing shutoff valve 43 on detection line 4, the compressed air is introduced from the rear side of detection filter 40B via compressed air inlet line 6, forming a flow path for cleaning the filter. Since shutoff valve 62 is open, a flow path is formed for the compressed air after filter cleaning to be introduced into inlet section 20 of centrifuge 2. Furthermore, by closing shutoff valve 43 on detection line 4, compressed air is prevented from flowing out to the downstream side of detection filtering unit 40 on detection line 4, ensuring reliable filter cleaning.

[0050] Furthermore, when introducing compressed air, the check valve 44 can block the flow of compressed air to the confluence of the detection line 4 and the separation liquid line 3. In this embodiment, a manual valve (not shown) may be provided upstream of the check valve 44 in the detection line to block the inlet of the detection line 4 branching off from the separation liquid line 3. This prevents compressed air from flowing into the entire detection line 4 before and after passing through the centrifuge, and allows compressed air to be introduced only into the detection filtering unit 40.

[0051] Furthermore, a check valve 63 is provided near the confluence of the flow paths where the compressed air in the compressed air inlet line 6 leads to the three-way automatic valve 1 and the inlet part 20 of the centrifuge 2. By providing this check valve 63, it is possible to prevent the inflow of the liquid to be treated during normal operation.

[0052] Next, cleaning via the cleaning agent introduction line 7 will be described. The system is configured so that the cleaning agent is introduced from the rear side of the detection filtering unit 40 via the cleaning agent introduction line 7, and the cleaning agent after filter cleaning can be introduced from the introduction part 20 side of the centrifuge 2. The cleaning agent introduced from the introduction part 20 of the centrifuge 2 is discharged as discharge sludge from the centrifuge 2. By introducing the cleaning agent after cleaning the detection filter 40B into the centrifuge 2, it becomes possible to clean not only the detection filter 40B but also the centrifuge 2.

[0053] The cleaning agent used is preferably an oil-soluble cleaning agent containing a paraffin-based or aromatic solvent, but it is also possible to use a water-soluble solvent containing an environmentally friendly surfactant, glycol solvent, chelating agent, etc. For example, oil-soluble or water-soluble cleaning agents (product name: Unisol series) manufactured by Nippon Yuka Kogyo Co., Ltd. can be used.

[0054] In this embodiment, the timing for cleaning the detection filter 40B is preferably immediately after the solid content discharge process of the centrifuge 2 shown in Fig. 3. Periodic filter cleaning can maintain monitoring accuracy.

[0055] In the cleaning agent introduction line 7, the cleaning agent can be supplied from the rear side of the detection filter 40B from a cleaning agent tank (not shown) via a supply pump 71 to clean the filter. The cleaning agent is supplied from the rear side of the detection filter 40B by closing the shutoff valve 43 and opening the shutoff valves 72 and 62, and the cleaning agent used to clean the filter can be introduced into the introduction part 20 of the centrifuge 2 because the shutoff valve 62 is open. Because the shutoff valve 43 of the detection line 4 is closed, the cleaning agent introduced from the cleaning agent introduction line 7 is prevented from flowing downstream of the detection line 4, ensuring that the filter can be cleaned with the cleaning agent.

[0056] Furthermore, when introducing the cleaning agent, the check valve 44 can block the flow of the cleaning agent to the confluence of the detection line 4 and the separation liquid line 3. In this embodiment, a manual valve (not shown) may be provided upstream of the check valve 44 in the detection line to block the inlet of the detection line 4 branching off from the separation liquid line 3. This prevents the cleaning agent from flowing into the entire detection line 4 before and after passing through the centrifuge, and allows the cleaning agent to be introduced only into the detection filtering unit 40.

[0057] A check valve 63 is provided near the confluence of the flow paths of the cleaning agent in the cleaning agent introduction line 7 leading to the three-way automatic valve 1 and the introduction part 20 of the centrifuge 2. By providing this check valve, it is possible to prevent the liquid to be treated from flowing into the cleaning agent introduction line 7 during normal operation.

[0058] In this embodiment, either the compressed air introduction line 6 or the cleaning agent introduction line 7 may be provided, or both may be provided simultaneously. When both are provided simultaneously, it is preferable to vary the timing of cleaning with compressed air and cleaning with cleaning agent. For example, cleaning with compressed air can be performed every day, and cleaning with cleaning agent can be performed once every few days or once a week.

[0059] The compressed air introduction line 6 and the cleaning agent introduction line 7 may also be installed when the flow rate monitoring system is cleaned. For example, they can be connected by providing a connection port in the piping upstream of the shutoff valve 43 on the downstream side of the detection and filtering unit 40. Also, a connection port is provided downstream of the check valve 44 on the upstream side of the detection and filtering unit 40, and a connection port is provided at the confluence of the flow paths leading to the three-way automatic valve 1 and the introduction section 20 of the centrifuge 2. By connecting the above connection ports to each other, flow paths for the cleaning liquid and compressed air can be formed, allowing the compressed air and cleaning agent after filter cleaning to be introduced into the introduction section 20 of the centrifuge 2.

[0060] In this embodiment, a compressed air supply device (not shown) for supplying the cleaning agent may be separately installed in the cleaning agent tank (not shown) to pressurize the cleaning agent tank and supply the cleaning agent, without providing the supply pump 71 in the cleaning agent introduction line 7. Also, a compressor in the compressed air introduction line 6 may be connected to the cleaning agent tank to pressurize the tank.

[0061] In this embodiment, when the cleaning agent from the cleaning agent introduction line 7 is used, after the filter has been washed, the used cleaning agent may be merged into the flow path of the sludge discharged from the sludge discharge part 23 of the centrifuge 2 shown in Fig. 6, and discharged without passing through the inside of the centrifuge 2. For example, in the cleaning agent introduction line 7, the cleaning agent is supplied from a cleaning agent tank (not shown) via a supply pump 71 from the rear side of the detection filter 40B to wash the filter, and the used cleaning agent used for washing can be discharged to the sludge discharge part 23 side without passing through the introduction part 20 of the centrifuge 2 by closing the shutoff valve 62 and opening the shutoff valve 64.

[0062] In this embodiment, compressed air may be introduced into the flow path joining the sludge discharge portion 23 after the filter has been cleaned from the compressed air introduction line 6 .

[0063] The shutoff valves 62 and 64 may be configured to be switchable, for example, between cleaning with the cleaning agent in the cleaning agent introduction line 7 and cleaning with the compressed air in the compressed air introduction line 6. In the present embodiment, it is preferable that one of the shutoff valves 62 and 64 is opened and the other is closed.

[0064] FIG. 7 is an explanatory diagram illustrating an example of the second embodiment. Figure 7 shows an example of a pressure monitoring system that monitors the state of a centrifuge in which a separated liquid obtained by separating a liquid to be treated by the centrifuge is provided with a separated liquid line and a detection drain line branching off from the separated liquid line. In Figure 7, the same reference numerals as in Figure 1 denote the same components, and therefore their explanations will be omitted.

[0065] In the case of a pressure monitoring system, in the detection filtering unit 40, a pressure gauge P1 is provided upstream of the detection filter 40B and a pressure gauge P2 is provided downstream, and the control unit 5 calculates the differential pressure between the pressure measured by the pressure gauge P1 and the pressure measured by the pressure gauge P2, and performs pressure monitoring control based on the calculated differential pressure.

[0066] A catch tank 45 is provided downstream of the constant flow valve 41, and an atmospheric vent 46 is provided in the catch tank 45, leaving the downstream side open to the atmosphere, thereby lowering the pressure gauge P2. Therefore, when the valve is blocked, the pressure gauge P1 is approximately at the pressure indicated by the pressure gauge PG, and the pressure on the pressure gauge P2 is at atmospheric pressure, resulting in a large differential pressure. As a result, a differential pressure is easily generated, making it easy to detect. In this embodiment, it is preferable to provide a pump (not shown) downstream of the catch tank 45.

[0067] In this embodiment, a control flow in the case where pressure monitoring is performed instead of the flow rate monitoring shown in FIG. 5 is shown in FIG.

[0068] In Fig. 8, pressure monitoring is performed. In pressure monitoring, the determination in S5 shown in Fig. 5 becomes a determination like S8. Other than that, control is performed in the same way as in the case of flow rate monitoring.

[0069] The control unit 5 preliminarily sets an upper limit threshold value for the differential pressure between the pressure measured by the pressure gauge P1 and the pressure measured by the pressure gauge P2, and also preliminarily sets a predetermined detection time.

[0070] As shown in FIG. 8, it is determined whether or not a state in which the differential pressure is equal to or greater than a preset upper limit threshold value has been maintained for a preset detection time or longer (S8).

[0071] If it has not continued (NO in S8), pressure monitoring in S8 continues. On the other hand, if the condition continues (YES in S8), it is considered as abnormal sludge deposition and an alarm is issued (S6).

[0072] Next, as in the case of flow rate monitoring, an alarm is issued and the process of S7 is executed, and the centrifuge is brought to an emergency stop.

[0073] When the precipitated sludge (solids) flows into the separated liquid side, it accumulates on the detection filter inside the filter housing, causing a difference in the pressure gauges before and after the filter, and the differential pressure calculated from the difference between the pressure gauge P1 before the filter and the pressure gauge P2 after the filter rises, so if there is no false detection, the differential pressure will exceed the upper threshold and remain in this state for longer than the detection time, making it possible to detect the deposition of sludge.On the other hand, large particles of the same size as or smaller than the filter opening are centrifuged with high efficiency, so nothing is captured in the filter and no pressure difference occurs before and after the filter, allowing the centrifuge to continue operating.

[0074] By controlling in this manner, a decrease in separation performance can be detected quickly, and as a result, the state of decreased separation performance can be quickly restored, and equipment malfunctions can be prevented.

[0075] In the above explanation, in the judgment of S8, it is determined whether the state in which the measurement value is equal to or greater than a predetermined differential pressure upper threshold continues for a predetermined detection time or more, but it is not necessary to determine whether the state continues for a predetermined detection time or more.

[0076] In the pressure monitoring of this embodiment, filter cleaning can be performed in the same manner as in the case of FIG. 6, and therefore a description thereof will be omitted.

[0077] According to the present invention, in the past, the centrifuge would become completely clogged with sludge (solid content), and in some cases, the occurrence of abnormal sludge deposition would be noticed only after a malfunction of the equipment occurred during operation. However, with the present invention, it is possible to quickly detect malfunctions of the equipment by "filter clogging in a short period of time."

[0078] Furthermore, factors that cause a decline in the separation performance of a centrifuge are not limited to the deposition of more sludge than expected, but include a variety of other factors such as an increase in the processing flow rate, a setting of a sludge discharge timer interval that is too long, a drop in processing temperature, an increase in the viscosity of the processing liquid, etc. Because the present invention detects a decline in separation performance, it also makes it possible to detect improper operating conditions and settings, enabling the operation of a centrifuge with stable performance. [Explanation of symbols]

[0079] 1: Three-way automatic valve 2: Centrifuge 20: Introduction 21: Electric motor 22:Separated liquid discharge section 23: Sludge discharge section 200: Separation plate 201: Solids storage section 202: Valve body 203: Sludge discharge outlet 3: Separation liquid line 30: Separation liquid 30a: Part of the separated liquid 31: Back pressure valve PG: Pressure gauge 4: Detection line 40: Detection filtering unit 40A: Housing 40B: Detection filter P1: Pressure gauge P2: Pressure gauge 41: Constant flow valve 42:Flowmeter 43:Shut-off valve 44: Check valve 45: Catch Tank 46: Atmospheric release vent 5: Control section 6: Compressed air introduction line 61:Shut-off valve 62:Shut-off valve 63: Check valve

Claims

1. The liquid to be treated is introduced into the centrifuge (2) through an inlet (20), The apparatus includes a centrifuge (2) having a structure in which a separation plate (200) of the centrifuge (2) is rotated by an electric motor (21), the introduced liquid to be treated is separated into sludge and separated liquid, the sludge is discharged from a sludge discharge part (23), and the separated liquid is discharged to the outside from a separated liquid discharge part (22), The separated liquid discharged from the separated liquid discharge part (22) is introduced into a separated liquid line (3) equipped with at least a back pressure valve (31) and a pressure gauge (PG), The system has a structure in which a part of the separated liquid introduced into the separated liquid line (3) is guided to a detection line (4) equipped with at least a detection filtering unit (40), a constant flow valve (41), and a flow meter (42) by adjusting the back pressure valve (31), The control unit (5) is connected to at least the flow meter (42) and the electric motor (21), The control unit (5) stops the motor (21) when it determines that the value measured by the flow meter (42), which measures the flow rate adjusted by the constant flow valve (41) provided downstream of the detection filtering unit (40), is equal to or less than a predetermined flow rate lower limit threshold.

2. The control unit (5) determines whether or not a state in which the measurement value of the flow meter (42) is equal to or less than a predetermined flow rate lower limit threshold has continued for a predetermined detection time set in advance, 2. The monitoring and control system for a centrifuge according to claim 1, wherein the electric motor (21) is stopped when it is determined that the detection time has continued for a predetermined period of time.

3. The liquid to be treated is introduced into the centrifuge (2) through an inlet (20), The apparatus includes a centrifuge (2) having a structure in which a separation plate (200) of the centrifuge (2) is rotated by an electric motor (21), the introduced liquid to be treated is separated into sludge and separated liquid, the sludge is discharged from a sludge discharge part (23), and the separated liquid is discharged to the outside from a separated liquid discharge part (22), The separated liquid discharged from the separated liquid discharge part (22) is introduced into a separated liquid line (3) equipped with at least a back pressure valve (31) and a pressure gauge (PG), The system has a structure in which a part of the separated liquid introduced into the separated liquid line (3) is guided to a detection line (4) equipped with at least a detection filtering unit (40) and a constant flow valve (41) by adjusting the back pressure valve (31), The detection filtering unit (40) is provided with a detection filter (40B), and a pressure gauge P1 is provided upstream of the detection filter (40B) and a pressure gauge P2 is provided downstream of the detection filter (40B), The control unit (5) is connected to at least the pressure gauge P1, the pressure gauge P2, and the electric motor (21), The control unit (5) calculates a differential pressure between the pressure measured by the pressure gauge P1 and the pressure measured by the pressure gauge P2, and determines whether the calculated differential pressure is equal to or less than a predetermined differential pressure upper limit threshold value set in advance, The monitoring and control system for a centrifuge is characterized in that, when it is determined that the calculated differential pressure is equal to or greater than a predetermined differential pressure upper limit threshold, the electric motor (21) is stopped.

4. The control unit (5) determines whether the calculated differential pressure is equal to or greater than a predetermined differential pressure upper limit threshold value for a predetermined detection time period, 4. The monitoring and control system for a centrifuge according to claim 3, wherein the electric motor (21) is stopped when it is determined that the detection time has continued for a predetermined period of time.

5. 5. The monitoring and control system for a centrifuge according to claim 3, wherein a catch tank (45) is provided downstream of the constant flow valve (41), and the catch tank (45) is provided with an atmospheric vent (46).

6. a three-way automatic valve (1) is provided upstream of the introduction section (20) of the centrifuge (2) for the liquid to be treated, which is capable of switching the flow of the liquid to be treated to a flow path toward the centrifuge (2) or a flow path toward a storage tank for the liquid to be treated; The control unit (5) is connected to the three-way automatic valve (1), 5. The monitoring and control system for a centrifuge according to claim 1, wherein the electric motor (21) is stopped and the flow path direction of the three-way automatic valve (1) on the centrifuge (2) side is switched to the flow path direction on the storage tank side of the liquid to be treated.

7. 5. The centrifuge monitoring and control system according to claim 1, wherein the detection filtering unit (40) comprises a filter housing (40A) and a detection filter (40B) housed in the housing.

8. 5. The monitoring and control system for a centrifuge according to claim 1, wherein a shutoff valve (43) is provided between the detection and filtering unit (40) and the constant flow valve (41).

9. 8. The monitoring and control system for a centrifuge according to claim 7, wherein a compressed air introduction line (6) is connected to the detection line (4) downstream of the detection filtering unit (40), and compressed air introduced via the compressed air introduction line (6) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to air wash the detection filter (40B) in the detection filtering unit (40).

10. 8. The monitoring and control system for a centrifuge according to claim 7, wherein a cleaning agent introduction line (7) is connected to the detection line (4) downstream of the detection filtering unit (40), and the cleaning agent introduced via the cleaning agent introduction line (7) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to clean the detection filter (40B) in the detection filtering unit (40).

11. 11. The monitoring and control system for a centrifuge according to claim 10, further comprising a flow path for introducing the cleaning agent used to clean the detection filter (40B) into an inlet (20) of the centrifuge (2).

12. A compressed air introduction line (6) and a cleaning agent introduction line (7) are connected to the detection line (4) downstream of the detection filtering unit (40); The compressed air introduced through the compressed air introduction line (6) is supplied from the downstream side of the detection filtering unit (40) to the upstream side thereof to air-clean the detection filter (40B) in the detection filtering unit (40), and 8. The monitoring and control system for a centrifuge according to claim 7, wherein the cleaning agent introduced through the cleaning agent introduction line (7) is supplied from the downstream side to the upstream side of the detection filtering unit (40) to clean the detection filter (40B) in the detection filtering unit (40).

13. 13. The monitoring and control system for a centrifuge according to claim 12, further comprising a flow path for introducing the compressed air or cleaning agent after cleaning the detection filter into an inlet portion of the centrifuge.

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