GB2601899A

GB2601899A - Pump clogging detection system

Info

Publication number: GB2601899A
Application number: GB2115345.7A
Authority: GB
Inventors: Itoigawa Nobuo; Mikami Taisei
Original assignee: Fuji Electric Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 2020-12-08
Filing date: 2021-10-25
Publication date: 2022-06-15
Anticipated expiration: 2041-10-25
Also published as: CN114623098A; GB2601899B; JP2022090957A; GB202115345D0; TW202229899A; KR20220081263A; TWI821762B; KR102549248B1

Abstract

Pump clogging detection system for a fluid flow channel of a pump driven by an electric motor 30 so as to pump or draw fluid, has a clogging detector 70 provided in a control means 80 of a power converter 20; the clogging detector includes functions that seta first score based on electric current limiting, output torque limiting, output power limiting, or a decrease in an output frequency of the power converter, e.g. when the electric motor is overloaded due to the clogging and an electric current is increased; a second function sets a score in accordance with whether overcurrent limiting is being performed; and a third function to sets a score in accordance with whether an overcurrent protection is being performed; the clogging detector infers an obstructed flow condition based on one or more scores. Preferably, clogging of an intake pipe 42 or an exhaust pipe 43, of a vacuum pump 40, by foreign matter and solidified deposits is detected and by monitoring the three scores and pressure sensors 60 a blockage can be located. Controller 80 may be a PLC, a power converter program may be stored in the cloud, scores may be stored on a memory card.

Description

Intellectual Property Office Application No G1321153457 RTM Date:5 April 2022 The following terms are registered trade marks and should be read as such wherever they occur in this document:

USB

Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo

TITLE OF THE INVENTION

PUMP CLOGGING DETECTION SYSTEM

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to a technology that detects clogging due to deposits adhering to a pump pipe, and specifically relates to a pump clogging detection system for detection of clogging in a pump that draws or pumps fluid such as gas or liquid.

2. Description of the Related Art

[0002] For example, in a semiconductor manufacturing apparatus, an impeller of a vacuum pump is driven by an electric motor in order to maintain the inside of a chamber (furnace) in a vacuum state during a film forming process such as sputtering. In such a case, products, formed by a chemical reaction of a gas introduced into the chamber with a film forming material, adhere to and are deposited on the inner walls of an intake pipe and an exhaust pipe of the vacuum pump, and further adhere to and are deposited on the impeller, thus causing the vacuum pump to be clogged by the deposits. Further, as the deposits increase, the load torque of the electric motor increases, and the electric motor becomes overheated. In a worst case scenario, the electric motor and the vacuum pump cease to operate.

[0003] In a conventional maintenance system, clogging is detected and deposits are removed by performing an inspection each time the vacuum pump in operation suddenly ceases to operate or by performing periodic inspections. However, needless to say, a problem such as a sudden cessation of operation of the vacuum pump needs to be avoided. In addition, even if periodic inspections are performed, it is difficult and complicated to determine when inspections can be optimally performed because the type of gas and a procedure used in a semiconductor manufacturing process may vary. For such reasons, it is desirable to detect clogging before the operation of the vacuum pump is interrupted.

[0004] Patent Document 1 discloses a technology utilized in a system that removes dust adhering to a filter by an airflow. The system includes means for measuring a drive current of an electric motor that generates an airflow, means for selecting the upper limit value of the drive current from a plurality of values, and means for measuring a period of time (duration) during which the measured value of the drive current continues to exceed a setting value. The drive current of the electric motor is changed in accordance with the above-described duration. In the conventional technology, clogging of the filter due to dust is detected based on the above-described duration, and the dust is efficiently removed by increasing the upper limit value of the drive current of the electric motor such that the electric motor rotates with high torque.

[0005] In the conventional technology disclosed in Patent Document 1, the duration during which the measured value of the drive current continues to exceed the setting value needs to be measured in order to detect clogging of the filter. Thus, a calculation process is complicated.

[0006] The present invention is conceived in view of the above-described problems, and aims to provide a pump clogging detection system that enables efficient maintenance work by securely detecting clogging in a fluid flow channel, without requiring inspection work each time a problem such as a sudden cessation of a pump occurs or requiring periodic inspection work.

RELATED-ART DOCUMENTS PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent No. 4973477 (claims 1 to 3, paragraphs [0035] to [0045], FIG. 5, etc.)

SUMMARY OF THE INVENTION

[0008] Accordingly, the invention according to 7.0 claim 1 is directed to a pump clogging detection system for detection of clogging in a fluid flow channel of a pump. The pump clogging detection system includes a power converter, an electric motor controlled by the power converter, and the pump driven by the electric motor so as to pump or draw fluid. A clogging detector provided in control means of the power converter includes a first function to set a first score in accordance with whether an electric current limiting operation, an output torque limiting operation, or an output power limiting operation is being performed with respect to the electric motor, or in accordance with an amount of decrease in an output frequency of the power converter, when the electric motor is overloaded due to the clogging and an electric current of the electric motor is increased, a second function to set a second score in accordance with whether an overcurrent limiting operation is being performed with respect to the electric motor, and a third function to set a third score in accordance with whether an overcurrent protection operation is being performed so as to eliminate an overcurrent condition of the electric motor. The clogging detector detects the clogging based on one or more scores of the first score through the third score.

[0009] The invention according to claim 2 is directed to the pump clogging detection system l; according to claim 1, wherein the clogging detector further Includes a fourth function to set a fourth score in accordance with whether the overcurrent protection operation is being performed at startup of the electric motor, and the clogging detector detects the clogging based on the fourth score and the one or more scores of the first score through the third score.

[0010] The invention according to claim 3 is directed to the pump clogging detection system according to claim 1 or 2, wherein the clogging detector detects the clogging based on a cumulative score value obtained by adding scores together.

[0011] The invention according to claim 4 is directed to the pump clogging detection system according to claim 3, further comprising a pressure sensor disposed on the fluid flow channel to measure a pressure value, wherein the clogging detector detects the clogging based on the cumulative score value and the measured pressure value.

[0012] The invention according to claim 5 is directed to the pump clogging detection system according to claim 4, wherein the clogging detector further includes a fifth function to compare a combination of the cumulative score value and the measured pressure value to a predetermined threshold, estimate a location of the clogging, and output a result of the estimated location.

[0013] The invention according to claim 6 is directed to the pump clogging detection system according to claim 5, wherein the cumulative score value is calculated in a current calculation cycle (a calculation cycle at the current time) and set as a current cumulative score value (a cumulative score value calculated at the current time), and the fifth function compares a combination of the current cumulative score value and the measured pressure value to the predetermined threshold, and estimates the location of the clogging.

[0014] The invention according to claim 7 is directed to the pump clogging detection system according to claim5, wherein a cumulative score value calculated in an immediately previous calculation cycle is set as an immediately previous cumulative score value, and a current cumulative score value is obtained by adding the cumulative score value of the scores to the immediately previous cumulative score value, the cumulative score value of the scores being calculated in a current calculation cycle, and the fifth function compares a combination of the current cumulative score value and the measured pressure value to the predetermined threshold, and estimates the location of the clogging.

[0015] The invention according to claim 8 is directed to the pump clogging detection system according to any one of claims 5 to 7, wherein the location of the clogging estimated by the fifth function is displayed on a monitor screen, transmitted to an external device via a network, or recorded in a recording medium.

[0016] The invention according to claim 9 is directed to the pump clogging detection system according to any one of claims 6 to 8, wherein the current cumulative score value is displayed on a monitor screen, transmitted to an external device via a network, or recorded in a recording medium.

[0017] The invention according to claim 10 is directed to the pump clogging detection system according to any one of claims 1 to 9, wherein the pump is a vacuum pump, and the fluid flow channel is an exhaust pipe or an intake pipe of the vacuum pump.

[0018] According to the present invention, clogging in a fluid flow channel can be securely detected without requiring inspection work each time a problem such as a sudden cessation of a pump occurs or requiring periodic inspection work. Further, the location of clogging in the pump can be estimated, and thus, inspection/cleaning work can be facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other aims and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: FIG. 1 is a configuration diagram illustrating a clogging detection system according to a first embodiment of the present invention; FIG. 2 is a configuration diagram illustrating a clogging detection system according to a second embodiment of the present invention; FIG. 3 is a configuration diagram illustrating a clogging detection system according to a third embodiment of the present invention; FIG. 4 is a flowchart of an exemplary detection process according to the embodiments; and FIG. 5 is a diagram illustrating the operations of a power converter and a controller to which functions of a clogging detector are separately allocated.

DESCRIPTION OF THE EMBODIMENTS

[0020] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments of the present invention, a vacuum pump clogging detection system used in a semiconductor manufacturing process will be described; however, the present invention is directed to various types of fluid machines that draw and pump fluid such as gas and liquid. Further, the term "pump" includes a compressor.

[0021] FIG. 1 is a configuration diagram Illustrating a clogging detection system according to a first embodiment of the present invention.

FIG. 1 depicts a power supply 10 such as a three-phase commercial power supply, a power converter 20 equipped with, for example, a variable-voltage variable-frequency (VVVF) inverter and a control circuit thereof, and an electric motor 30 such as an induction motor or a synchronous motor. An impeller 41 in a vacuum pump 40 is driven by the electric motor 30.

[0022] A chamber (furnace) 50 is coupled to the Impeller 41 via an intake pipe 42, and an exhaust pipe 43 is provided on the opposite side of the Impeller 41 from the intake pipe 42. The Impeller 41 driven by the electric motor 30 draws air from the chamber 50 and discharges the air from the l; exhaust pipe 43, thereby maintaining the inside of the chamber SO in a vacuum state. The chamber SO may be used for film formation on a semiconductor substrate, for example. The intake pipe 42, the Impeller 41, and the exhaust pipe 43 described above constitute a fluid flow channel recited in the claims. The gist of the present invention is a function to detect clogging of the pump, and thus, the types (AC, DC, and the number of phases) of the power supply 10 and the electric motor 30, the conversion method and configuration of the power converter 20, and the like are not particularly limited.

[0023] An exhaust pressure sensor 60 is connected to the exhaust pipe 43. The exhaust pressure sensor 60 measures an exhaust pressure value of the vacuum pump 40, and the measured exhaust pressure value is input into the clogging detector 70 included in the control circuit of the power converter 20. As will be described later, the clogging detector 70 Includes functions to detect clogging in the vacuum pump 40 (including the intake pipe 42, the exhaust pipe 43, and the impeller 41) based on a cumulative value of a plurality of scores as well as the above-described measured exhaust pressure value and predetermined thresholds, and to output the result. The cumulative value of the plurality of scores are set in accordance with various limiting operations and a protection operation performed by the power converter 20.

[0024] For example, products 101, solidified by various gases used for film formation on a semiconductor substrate, are generated in the J5 chamber 50. During a process in which the products 101 and dust are discharged via the impeller 41, some of the products 101 and dust adhere to the inner walls of the intake pipe 42 and the exhaust pipe 43, the impeller 41, and the like, and as a result, deposits 102 are formed. The clogging detector 70 detects clogging due to the products 101 and the deposits 102.

[0025] In the present embodiment, the exhaust pressure value measured by the exhaust pressure sensor 60 is used to detect clogging. However, an intake pressure sensor (not illustrated) may be connected to the intake pipe 42, and an intake pressure value measured by the intake pressure sensor may be used to detect clogging.

Alternatively, both the intake pressure sensor and the exhaust pressure may be provided. In this case, one (larger one, for example) of the measured exhaust pressure value and the measured intake pressure value may be used to detect clogging, or an average value of the measured exhaust pressure value and the measured intake pressure value may be used to detect clogging.

[0026] Next, FIG. 2 is a configuration diagram illustrating a clogging detection system according to a second embodiment of the present invention. In the second embodiment, a controller 80 configured by a personal computer, a programmable logic controller (PLC), or the like is used to control the power converter 20. In this case, an exhaust pressure value measured by the exhaust pressure sensor 60 is input into the clogging detector 70 of the power converter 20 via the controller 80. Further, FIG. 3 l; is a configuration diagram illustrating a clogging detection system according to a third embodiment of the present invention. In the third embodiment, the controller 80 is provided with the clogging detector 70. In this case, an exhaust pressure value measured by the exhaust pressure sensor 60 is input into the clogging detector 70 within the controller 80.

[0027] The clogging detector 70 may be provided within the power converter 20 as illustrated in FIG. 1 and FIG. 2, or within the controller 80 as Illustrated in FIG. 3. Alternatively, control means (program) of the power converter 20 may be provided on a cloud, and the control means may be provided with a clogging detection function according to the present invention.

[0028] Next, an exemplary clogging detection process performed by the clogging detector 70 according to the embodiments will be described with reference to a flowchart of FIG. 4. The detection process illustrated in FIG. 4 is periodically performed.

[0029] First, if the vacuum pump 40 is used for a long period of time, products 101 may adhere to the inner wall of the intake pipe 42, the inner wall of the exhaust pipe 43, and the lie, and as a result, deposits 102 may be formed. Such products 101 and deposits 102 may enter the inside of the impeller 41. In this case, the electric motor 30 that drives the impeller 41 would be overloaded, thereby causing the electric current flowing-from the power converter 20 into the electric motor 30, input power, and the output torque of the electric motor 30 to be increased.

[0030] Typically, the power converter 20 is capable of limiting an output current, an output frequency, output power, the output torque of the electric motor 30, and the like to predetermined values, as controlled by the control circuit. For example, if the output current of the power converter 20 exceeds a predetermined value, and thus an electric current limiting operation is being performed (yes in step 51 of FIG. 4), the output frequency of the power converter 20 decreases. The amount of decrease in the output frequency is recorded in a memory (step S2). Then, a first score is calculated based on the amount of decrease in the output frequency, and the calculated first score is set (step S3). If the electric current limiting operation is not performed (no in step 51), the first score is set as "0".

[0031] Next, for example, if deposits 102 adhere to the inside of the impeller 41 during high-speed rotation of the electric motor 30, the electric motor 30 will become rapidly overloaded. In this case, an overcurrent limiting operation is performed in order to prevent an overcurrent greater than or equal to a threshold (a value greater than the predetermined value used in the case of the electric current limiting operation in step Si) from flowing from the power converter 20 into the electric motor 30. If the overcurrent limiting operation is being performed (yes in step 54), a predetermined second score is set (step S5). If the overcurrent limiting operation is not performed (no in step 54), the second score is set as "0". If the above-descried overcurrent condition is not eliminated, an overcurrent protection operation is performed (yes in step 56) by shutting off power supplied from the power converter 20 so as to stop the electric motor 30. Then, a predetermined third score is set (step S7). If the overcurrent protection operation is not being performed (no in step S6), the third score is set as "0".

[0032] Further, it is determined whether the overcurrent protection operation is being performed when the currently-stopped electric motor 30 is restarted. If it is determined that the overcurrent protection operation is being performed (yes in step S8), a predetermined fourth score is set (step 59). If the overcurrent protection operation is not being performed when the electric motor 30 is restarted (no in step 58), the fourth score is set as "0".

The above-described determination (step S8) is performed not only when the overcurrent protection -1.3-operation (step 36) is continued, but also when the pump is started after being stopped for a long period of time since steps Si through S5. Specifically, if the operation of the pump is stopped for a long period of time after steps 51 through SS and is then started, the deposits 102 adhering to the intake pipe 42 or new products 101 may flow into the impeller 41, thereby causing clogging, and as a result, the overcurrent protection operation may be performed at startup of the electric motor 30. In such a case, the above-described determination in step 38 is applicable as well. Note that the above-described determination (step 58) as to whether the overcurrent protection operation is being performed at startup of the electric motor 30 is not necessarily performed in the present invention. That is, as described in claim 1, the clogging detector 70 may include at least a first function to set the first score in accordance with whether the electric current limiting operation is being performed (step S1), a second function to set the second score in accordance with whether the overcurrent limiting operation is being performed (step S4), and a third function to set the third score in accordance with whether the overcurrent protection operation is being performed (step S6). The clogging detector 70 can detect clogging by using the above-described first through third scores.

[0033] Thereafter, the current cumulative score value is calculated by adding the first through fourth scores to the immediately previous cumulative score value calculated in the immediately previous calculation cycle (step 310). Then, the added value (that is, the current cumulative score value) obtained in step S10 is combined with an exhaust pressure value measured by the exhaust pressure sensor 60 illustrated in FIG. 1 through FIG. 3. Then, the combination of the current cumulative score value and the measured exhaust pressure value is compared to various thresholds, which will be described later, and the location of clogging is estimated (step S11). The result is classified and is output so as to be displayed on a monitor, transmitted to an external network such as the Internet, or recorded in a recording medium (step S12). The current cumulative score value may also l; be displayed on the monitor, transmitted to the external network, or recorded in the recording medium as necessary. An operator who monitors the operation of a semiconductor manufacturing apparatus or on-site workers can identify the occurrence of 7.0 clogging based on the output result described above, and stop the electric motor 30 to perform inspection, cleaning, or any other work as necessary.

[0034] Thereafter, the current cumulative score value is recorded (step S13). Further, the first through fourth scores are cleared (step 314). As described above, because the current cumulative score value is stored each time, the trend for progression of clogging can be recorded and utilized to study film formation conditions in a semiconductor manufacturing process. In addition to the first through fourth scores (step 314), a value obtained by adding the first through fourth scores together (simply, a "cumulative score value") may also be cleared. The cumulative score value may be cleared at a timing when the inspection/cleaning work of the clogging is completed.

[0035] FIG. 5 is a diagram illustrating the operations of the power converter 20 and the controller 80 to which the functions of the clogging detector 70 are separately allocated. The power converter 20 performs steps 51 through 510 of FIG. 4. Then, the power converter 20 stores, in a transmission buffer for communication, the current cumulative score value obtained by adding first through fourth scores to the immediately previous cumulative score value, and transmits the l; communication data (current cumulative score value) to the controller 80.

[0036] In the power converter 20 of FIG. 5, the "immediately previous cumulative score value" is indicated in parentheses. This means that the 7.0 "immediately previous cumulative score value" can be added to the scores as necessary. In other words, in step S10 of FIG. 4, the immediately previous cumulative score value may be set to zero. That is, if the immediately previous cumulative score value is set as zero, and a cumulative value of the first through fourth scores Is used as the current cumulative score value, the current cumulative score value can be used as an instantaneous value each time the flowchart of FIG. 4 is performed for clogging detection.

[0037] In FIG. 5, the controller 80 stores the received current cumulative score value in a reception buffer for communication. Then, the controller 80 inputs the current cumulative score value into one input of comparison/estimation means 71, and inputs an exhaust pressure value measured by the exhaust pressure sensor 60 illustrated FIG. 1 through FIG. 3 into the other input of the comparison/estimation means 71. The comparison/estimation means 71 performs steps Sll and S12 of FIG. 4. The comparison/estimation means 71 combines the current cumulative score value with the measured exhaust pressure value, compares the combination of the current cumulative score value and the measured exhaust pressure value to thresholds al, a2, a3, and b_, and estimates the location of clogging. Then, the comparison/estimation means 71 outputs the result to, for example, the monitor screen 81 of the controller 80. The current cumulative score value may also be output to the monitor screen 81 separately. As described above, the result of the 7.0 comparison/estimation means 71 and the current cumulative score value may be transmitted to an external device as digital data, or may be recorded in any of various types of recording mediums such as a USB memory and a memory card.

[0038] The monitor screen 81 illustrated in FIG. displays an example of four quadrants defined by the thresholds ai, a2, a3, and bi. The combination of the current cumulative score value and the measured exhaust pressure value belongs to any of the four quadrants defined by the thresholds al, a2, a3, and ID'. For example, the threshold al is a threshold corresponding to the lower limit value of the exhaust pressure, the threshold a2 is a -1.7-threshold for warning an increase in the exhaust pressure, and the threshold ap is a threshold corresponding to the upper limit value of the exhaust pressure. If the exhaust pressure exceeds the threshold a3, it is desirable to issue an alert to prompt the operator or workers to stop the operation of the pump. Further, the threshold b_ is a threshold for warning an increase in the current cumulative score value. Needless to say, the number and significance (type) of the thresholds, the display format of the monitor screen 81, and the like are not limited to the above-described examples.

[0039] The four quadrants (1) through (4) displayed on the monitor screen 81 will be described. Empirically, the higher the measured exhaust pressure value is, the more deposits 102 tend to be in the exhaust pipe 43. Further, the higher the current cumulative score value is, the more deposits 102 tend to be in the intake pipe 42. The quadrants are set by taking the above into consideration. Specifically, the quadrant (1) indicates that a large amount of deposits 102 is present in the intake pipe 42 and the exhaust pipe 43, the quadrant (2) indicates that a large amount of deposits 102 is present in the intake pipe 42, and the quadrant (3) indicates that a large amount of deposits 102 is present in the exhaust pipe 43. The combination of the current cumulative score value and the measured exhaust pressure value is classified into any of the quadrants (1), (2), and (3), and is plotted and displayed. The quadrant (4) indicates that a small amount of deposits 102 is present in the intake pipe 42 and the exhaust pipe 43. Therefore, the combination of the measure value of the exhaust pressure and the cumulative score value is not plotted and displayed in the quadrant (4). However, if an impurity is caught up in the impeller 41 or any other abnormal situation occurs, the quadrant (4) may be used to display a warning.

[0040] As described above, in the embodiments of the present invention, scores are set in accordance with whether the electric current limiting operation, the overcurrent limiting operation, and the overcurrent protection operation are being performed, and a cumulative value of these scores is combined with an exhaust pressure value measured by the exhaust pressure sensor 60. In this manner, the location of clogging in the intake pipe 42, the Impeller 41, or the exhaust pipe 43 can be estimated and output. Accordingly, inspection/cleaning work can be promptly and accurately performed when clogging occurs, and thus, maintenance work of various pumps such as a vacuum pump can be efficiently performed.

INDUSTRIAL APPLICABILITY

[0041] The present invention can be utilized in various pumps as fluid machines that draw and pump fluids such as gases and liquids to detect clogging in fluid flow channels due to reaction products or impurities.

DESCRIPTION OF THE REFERENCE NUMERALS

[0042] power supply power converter 30 electric motor vacuum pump 41 impeller 42 intake pipe 43 exhaust pipe chamber (furnace) exhaust pressure sensor clogging detector 71 comparison/estimation means controller 81 monitor screen 101 product 102 deposit

Claims

WHAT IS CLAIMED IS1. A pump clogging detection system for detection of clogging in a fluid flow channel of a pump, the pump clogging detection system comprising: a power converter; an electric motor controlled by the power converter; and the pump driven by the electric motor so as to pump or draw fluid, characterized in that a clogging detector 15 provided in control means of the power converter includes a first function to set a first score in accordance with whether an electric current limiting operation, an output torque limiting operation, or an output power limiting operation is being performed with respect to the electric motor, or in accordance with an amount of decrease in an output frequency of the power converter, when the electric motor is overloaded due to the clogging and an electric current of the electric motor is increased, a second function to set a second score in accordance with whether an overcurrent limiting operation is being performed with respect to the electric motor, and a third function to set a third score in accordance with whether an overcurrent protection operation is being performed so as to eliminate an overcurrent condition of the electric motor, and the clogging detector detects the clogging based on one or more scores of the first score through the third score.
2. The pump clogging detection system according to claim 1, wherein the clogging detector further includes a fourth function to set a fourth score in accordance with whether the overcurrent protection operation is being performed at startup of the electric motor, and the clogging detector detects the clogging 15 based on the fourth score and the one or more scores of the first score through the third score.
3. The pump clogging detection system according to claim 1 or 2, wherein the clogging detector detects the clogging based on a cumulative score value obtained by adding scores together.
4. The pump clogging detection system 30 according to claim 3, further comprising a pressure sensor disposed on the fluid flow channel to measure a pressure value, wherein the clogging detector detects the clogging based on the cumulative score value and the measured pressure value.
5. The pump clogging detection system according to claim 4, wherein the clogging detector further includes a fifth function to compare a combination of the cumulative score value and the measured pressure value to a predetermined threshold, estimate a location of the clogging, and output a result of the estimated location.
6. The pump clogging detection system according to claim 5, wherein the cumulative score 90 value is calculated in a current calculation cycle and set as a current cumulative score value, and the fifth function compares a combination of the current cumulative score value and the measured pressure value to the predetermined threshold, and estimates the location of the clogging.
7. The pump clogging detection system according to claim 5, wherein a cumulative score value calculated in an immediately previous calculation cycle is set as an immediately previous cumulative score value, and a current cumulative score value is obtained by adding the cumulative score value of the scores to the immediately previous cumulative score value, the cumulative score value of the scores being calculated in a current calculation cycle, and the fifth function compares a combination of the current cumulative score value and the measured pressure value to the predetermined threshold, and estimates the location of the clogging.
8. The pump clogging detection system according to any one of claims 5 to 7, wherein the location of the clogging estimated by the fifth function is displayed on a monitor screen, transmitted to an external device via a network, or recorded in a recording medium.
9. The pump clogging detection system according to any one of claims 6 to 8, wherein the current cumulative score value is displayed on a monitor screen, transmitted to an external device via a network, or recorded in a recording medium.
10. The pump clogging detection system according to any one of claims 1 to 9, wherein the pump is a vacuum pump, and the fluid flow channel is an exhaust pipe or an intake pipe of the vacuum pump.