Pump blockage detection system

Abstract

The present invention provides a pump blockage detection system, which can detect blockage without being bothered by inspections or periodic inspections when the pump is stopped. The pump blockage detection system is a blockage detection system for a fluid flow path of a pump that is driven by a motor to pressurize or suck a fluid such as air, and a blockage detection unit provided in a control unit of a power conversion device includes: a first function, which sets a first score according to the presence or absence of a current limiting action, an output torque limiting action, or an output power limiting action of the motor when the motor is overloaded due to blockage and the current increases; a second function, which sets a second score according to the presence or absence of an overcurrent limiting action; and a third function, which sets a third score according to the presence or absence of an overcurrent protection action for removing the overcurrent of the motor, and detects blockage of a suction side piping or an exhaust side piping of a vacuum pump based on one or more of the first score to the third score.

Description

Technical Field

[0001] The present invention relates to a technology for detecting clogging of a pump caused by deposits attached to a pipe or the like, and more particularly to a clogging detection system in a pump for sucking or pressurizing fluids such as gas and liquid. Background Art

[0002] For example, in the film forming process such as sputtering in semiconductor manufacturing equipment, in order to maintain the chamber (furnace) in a vacuum state, the impeller constituting the vacuum pump is driven by a motor. In this case, the products of the chemical reaction between the gas introduced into the chamber and the film forming material adhere to and accumulate on the inner wall of the suction side piping and exhaust side piping of the vacuum pump and even on the impeller, and the deposits cause clogging of the vacuum pump. In addition, as the deposits increase, the load torque of the motor increases, the motor becomes overheated, and in the worst case, the motor and the vacuum pump stop.

[0003] Conventionally, a maintenance system has been adopted in which a vacuum pump is inspected when it stops suddenly during operation or is inspected regularly to detect blockage and remove the deposits.

[0004] However, it is necessary to avoid the trouble of sudden stop of the vacuum pump. In addition, even if the inspection is performed regularly, there are problems such as it is difficult and cumbersome to determine the most suitable time for inspection due to the differences in the types of gases and processes used in the semiconductor manufacturing process.

[0005] Therefore, it is desirable to detect clogging at a stage before it interferes with the operation of the vacuum pump.

[0006] Here, in Patent Document 1, the following technology is disclosed, namely, in a system for removing dust attached to a filter by airflow, the system includes: a unit for measuring the driving current of a motor that generates the above-mentioned airflow; a unit for selecting an upper limit value of the driving current from multiple values; and a unit for measuring the time (duration time) that the driving current measured value exceeds a set value, and changing the driving current of the motor according to the duration time.

[0007] In this conventional technology, clogging of the filter due to dust is detected based on the above-mentioned duration, and in this case, the upper limit value of the drive current of the motor is increased, and the dust is removed efficiently by rotating the motor with a high torque.

[0008] <Prior Art Literature>

[0009] <Patent Documents>

[0010] Patent Document 1: Japanese Patent No. 4973477 (Claims 1 to 3,

[0035] to

[0045] , Figure 5 wait) Summary of the invention

[0011] <Problems to be Solved by the Invention>

[0012] The conventional technology described in Patent Document 1 has a problem in that, in order to detect filter clogging, it is necessary to measure the duration during which the measured value of the drive current exceeds a set value, which complicates the calculation process.

[0013] Therefore, the problem to be solved by the present invention is to provide a pump blockage detection system which is not bothered by inspection operations corresponding to sudden troubles such as pump stoppage and regular inspection operations, and can reliably detect blockage of a fluid flow path and perform maintenance operations efficiently.

[0014] <Methods used to solve the problem>

[0015] In order to solve the above-mentioned problems, the invention of technical solution 1 includes a motor controlled by a power conversion device and a pump driven by the motor to pressurize or suck a fluid, and the invention of technical solution 1 is used to detect blockage of a fluid flow path constituting the pump.

[0016] The blockage detection unit provided in the control unit of the above-mentioned power conversion device includes:

[0017] a first function for setting a first score according to the presence or absence of a current limiting action, an output torque limiting action, or an output power limiting action on the motor when the motor is overloaded due to the blockage and the current of the motor increases;

[0018] A second function, which sets a second score according to the presence or absence of an overcurrent limiting action on the above-mentioned motor; and

[0019] The third function sets a third score according to the presence or absence of an overcurrent protection action for removing the overcurrent of the motor.

[0020] The blockage is detected based on one or more scores among the first score to the third score.

[0021] The invention of Technical Solution 2 is characterized in that, in the blockage detection system for the pump described in Technical Solution 1, the blockage detection unit also includes a fourth function, which sets a fourth score according to the presence or absence of overcurrent protection action when the motor is started, and detects the blockage based on one or more of the first score to the third score and the fourth score.

[0022] The invention of claim 3 is characterized in that, in the pump clogging detection system according to claim 1 or 2, the clogging detection unit detects the clogging based on a score cumulative value obtained by adding a plurality of the scores.

[0023] The invention according to claim 4 is characterized in that, in the pump clogging detection system according to any one of claims 1 to 3, the first score is calculated based on the amount of decrease in the output frequency of the power conversion device.

[0024] The invention of technical solution 5 is characterized in that, in the pump clogging detection system described in technical solution 3 or technical solution 4, the clogging detection unit detects the clogging based on the score cumulative value and the pressure measurement value of the pressure sensor arranged in the fluid flow path.

[0025] The invention of technical solution 6 is characterized in that, in the pump blockage detection system described in technical solution 5, the above-mentioned blockage detection unit includes a fifth function, which compares the combination of the above-mentioned score cumulative value and the above-mentioned pressure measurement value with a specified threshold value, thereby estimating the location where the above-mentioned blockage occurs, and outputs the result.

[0026] The invention of Technical Solution 7 is characterized in that, in the pump blockage detection system described in Technical Solution 6, the above-mentioned score cumulative value calculated through this calculation cycle is set as the current score cumulative value, and the combination of the above-mentioned current score cumulative value and the above-mentioned pressure measurement value is compared with a specified threshold value, thereby inferring the location where the above-mentioned blockage occurs.

[0027] The invention of Technical Solution 8 is characterized in that, in the pump blockage detection system described in Technical Solution 6, the above-mentioned score cumulative value calculated through the last operation cycle is set as the last score cumulative value, the above-mentioned score cumulative value and the cumulative values ​​of multiple scores in this operation cycle are added to obtain the current score cumulative value, and the combination of the above-mentioned current score cumulative value and the above-mentioned pressure measurement value is compared with a specified threshold value to infer the location where the above-mentioned blockage occurs.

[0028] The invention of technical solution 9 is characterized in that, in the pump blockage detection system described in any one of technical solutions 6 to 8, the location where the blockage is estimated by the fifth function is displayed on the display screen, or sent to the outside through a network, or recorded in a recording medium.

[0029] The invention of technical solution 10 is characterized in that, in the pump clogging detection system according to any one of technical solutions 7 to 9, the above-mentioned current score cumulative value is displayed on a display screen, or sent to the outside through a network, or recorded in a recording medium.

[0030] The invention of technical solution 11 is characterized in that, in the pump clogging detection system according to any one of technical solutions 1 to 10, the pump is a vacuum pump, and the fluid flow path is an exhaust side pipe or an intake side pipe of the vacuum pump.

[0031] <Effects of the Invention>

[0032] According to the present invention, blockage in the fluid flow path can be reliably detected without being bothered by sudden and troublesome inspection operations due to pump stoppage, etc., or regular inspection operations. In addition, the blockage position in the pump can be estimated, thereby facilitating inspection / cleaning operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a block diagram of a congestion detection system according to a first embodiment of the present invention.

[0034] Figure 2 It is a configuration diagram of a congestion detection system according to a second embodiment of the present invention.

[0035] Figure 3 It is a configuration diagram of a congestion detection system according to a third embodiment of the present invention.

[0036] Figure 4 It is a flowchart showing a typical congestion detection operation in each embodiment.

[0037] Figure 5 This is an operation explanation diagram when the function of the congestion detection unit is dispersedly provided in the power conversion device and the controller. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0039] It should be noted that, in each embodiment, although the present invention is described as a blockage detection system for a vacuum pump used in a semiconductor manufacturing process, the present invention is aimed at various fluid machines that suck or pressurize fluids such as gases and liquids, and the concept of "pump" includes compressors.

[0040] Figure 1 It is a block diagram of a congestion detection system according to a first embodiment of the present invention.

[0041] exist Figure 1 In the figure, 10 is a power source such as a three-phase commercial power source, 20 is a power conversion device including, for example, a VVVF (variable voltage variable frequency) inverter and its control circuit, and 30 is an electric motor such as an induction motor and a synchronous motor, and the impeller 41 in the vacuum pump 40 is driven by the electric motor 30.

[0042] The chamber (furnace) 50 is connected to the impeller 41 via the air intake pipe 42, and an exhaust pipe 43 is provided on the opposite side of the air intake pipe 42. The impeller 41 driven by the motor 30 sucks the air in the chamber 50 and discharges it from the exhaust pipe 43, so that the inside of the chamber 50 is kept in a vacuum state. The chamber 50 is used, for example, for performing a film forming process on a semiconductor substrate. The air intake pipe 42, the impeller 41, and the exhaust pipe 43 constitute a fluid flow path in the technical solution.

[0043] It should be noted that since the main purpose of the present invention is the clogging detection function of the pump, the type of power supply 10, motor 30 (AC, DC, number of phases), conversion method and structure of the power conversion device 20 are not particularly limited.

[0044] The exhaust pressure sensor 60 is connected to the exhaust side piping 43 , and the exhaust pressure measurement value of the vacuum pump 40 based on the exhaust pressure sensor 60 is input to the clogging detection unit 70 included in the control circuit of the power conversion device 20 .

[0045] As described in detail later, the blockage detection unit 70 has the following function, namely, based on the cumulative value of multiple scores of various restriction actions and protection actions of the power conversion device 20, the above-mentioned exhaust pressure measurement value and the specified threshold value, it detects and outputs the blockage inside the vacuum pump 40 (including the intake side piping 42, the exhaust side piping 43, and the impeller 41).

[0046] In the chamber 50, for example, solidified products 101 are generated by using various gases in a film forming process on a semiconductor substrate. In the process where the products 101 and dust are exhausted via the impeller 41, they adhere to the inner walls of the air intake pipe 42 and the exhaust pipe 43, the impeller 41, etc., and become deposits 102. The clogging detection unit 70 is used to detect clogging caused by these products 101 and deposits 102.

[0047] In the present embodiment, the exhaust pressure measurement value of the exhaust pressure sensor 60 is used for clogging detection, but an intake pressure sensor (not shown) may be connected to the intake side pipe 42, and the intake pressure measurement value may be used for clogging detection. Alternatively, an exhaust pressure sensor and an intake pressure sensor may be provided, and the exhaust pressure measurement value and the intake pressure measurement value (for example, the larger one) or the average value of the two measurement values ​​may be used for clogging detection.

[0048] Next, Figure 2 It is a configuration diagram of a congestion detection system according to a second embodiment of the present invention.

[0049] This embodiment uses a controller 80 composed of a computer, a PLC (Programmable Logic Controller), etc. to control the power conversion device 20. In this case, the exhaust pressure measurement value of the exhaust pressure sensor 60 is input to the clogging detection unit 70 in the power conversion device 20 through the controller 80.

[0050] in addition, Figure 3 It is a configuration diagram of a congestion detection system according to a third embodiment of the present invention.

[0051] In this embodiment, the controller 80 includes a clogging detection unit 70 , and the exhaust pressure measurement value of the exhaust pressure sensor 60 is input to the clogging detection unit 70 in the controller 80 .

[0052] It should be noted that the clogging detection unit 70 can be used as follows: Figure 1 , Figure 2 The power conversion device 20 is provided inside the power conversion device 20, such as Figure 3 In this way, a control unit (program) of the power conversion device 20 may be provided inside the controller 80, or on the so-called cloud side, and the control unit may include the congestion detection function of the present invention.

[0053] Next, in each embodiment, based on Figure 4 A typical clogging detection operation performed by the clogging detection unit 70 will be described with reference to the flowchart of FIG. This detection operation is performed periodically.

[0054] First, when the vacuum pump 40 is used for a long time, the product 101 adheres to the inner wall of the air intake pipe 42, the inner wall of the air exhaust pipe 43, etc., and forms a deposit 102. In addition, the product 101 and the deposit 102 may enter the inside of the impeller 41. Therefore, the motor 30 for driving the impeller 41 becomes overloaded, and the current flowing into the motor 30 from the power conversion device 20, the input power, and the output torque of the motor 30 increase.

[0055] The power conversion device 20 is generally capable of limiting the output current, output frequency, output power, and output torque of the motor 30 to specified values ​​through the operation of the control circuit. For example, if the output current of the power conversion device 20 exceeds the specified value and the current limiting operation is activated ( Figure 4 If the output frequency of the power conversion device 20 is reduced (step S1 Yes), the reduction amount is recorded in the memory. In addition, a first score is calculated based on the reduction amount of the output frequency, and the first score is set (step S3). It should be noted that when the current limiting action is not working (step S1 No), the first score is set to "0".

[0056] Next, when the motor 30 is rotating at high speed, the deposit 102 adheres to the inside of the impeller 41, etc., and the motor 30 suddenly becomes overloaded, and the overcurrent limiting action is activated to prevent an overcurrent exceeding the threshold value (a value greater than the above-mentioned specified value when the current limiting action is determined in step S1) from flowing from the power conversion device 20 to the motor 30 (step S4 Yes), the preset second score is set (step S5). It should be noted that when the overcurrent limiting action does not work (step S4 No), the second score is set to "0".

[0057] Furthermore, when the overcurrent state is not eliminated, an overcurrent protection action such as cutting off the power supplied from the power conversion device 20 to stop the motor 30 is performed (step S6 Yes), and a preset third score is set (step S7). It should be noted that when the overcurrent protection action does not work (step S6 No), the third score is set to "0".

[0058] Furthermore, it is determined whether the overcurrent protection action is working when the stopped motor 30 is restarted. If it is working (step S8 Yes), a preset fourth score is set (step S9). It should be noted that when the overcurrent protection action is not working at the time of starting (step S8 No), the fourth score is set to "0".

[0059] Here, for the determination of the overcurrent protection action at startup (step S8), in addition to the situation where the overcurrent protection action (step S6) during operation is continuing, it is also possible that after steps S1 to S5, the operation of the pump is stopped for a long time and then the pump is started, and the deposits 102 attached to the suction side piping 42 and the new product 101 flow into the impeller 41 and cause blockage, thereby causing the overcurrent protection action at startup. This situation is also the object of determination in step S8.

[0060] It should be noted that the above-mentioned process of determining whether the overcurrent protection action is performed at startup (step S8) is not essential in the present invention. That is, as described in technical solution 1, the blockage detection unit 70 at least includes a first function of setting a first score according to whether the current limiting action (step S1) is performed, a second function of setting a second score according to whether the overcurrent limiting action (step S4) is performed, and a third function of setting a third score according to whether the overcurrent protection action (step S6) is performed, and the first to third scores are used for blockage detection.

[0061] Thereafter, the first to fourth scores are added to the previous score cumulative value calculated in the previous calculation cycle to calculate the current score cumulative value (step S10).

[0062] Then, the addition result of step S10 (the accumulated score of this time) and Figure 1 to Figure 3 The exhaust pressure measurement value combination of the exhaust pressure sensor 60 is compared with various threshold values ​​described later to estimate the location of the blockage (step S11), and the result is classified and output by displaying on a display, sending to an external network such as the Internet, recording on a recording medium, etc. (step S12). In addition, if necessary, the current score accumulation value is also displayed on a display, sent to an external network, recorded on a recording medium, etc.

[0063] An operator who monitors the operation of the semiconductor manufacturing apparatus or an on-site operator can recognize the occurrence of a blockage from the output and stop the motor 30 to perform an inspection / cleaning operation as necessary.

[0064] After that, the accumulated score of this time is recorded (step S13), and the first to fourth scores are cleared (step S14). In this way, by recording the accumulated score of this time each time, the progress of the clogging can be retained as a trend, which can be helpful for studying film forming conditions in semiconductor manufacturing processes.

[0065] Here, the sum of the scores (only the “score accumulation value”) may be cleared together with the clearing of the first to fourth scores (step S14 ), and the timing of clearing may be set to, for example, the time when the inspection / cleaning operation of the clogged part is completed.

[0066] Figure 5 This is an operation explanatory diagram of a case where the function of the blockage detection unit 70 is dispersedly provided in the power conversion device 20 and the controller 80 .

[0067] In the power conversion device 20, the Figure 4 In the processing of steps S1 to S10 in the above, the sum of the first to fourth scores and the previous score cumulative value is set as the current score cumulative value, stored in the communication transmission buffer, and the communication data is transmitted to the controller 80.

[0068] It should be noted that in Figure 5 The "previous score cumulative value" shown in brackets in the power conversion device 20 of FIG. 20 indicates that it is added to each score as needed. In other words, Figure 4 The last score cumulative value in step S10 is set to zero. That is, if the last score cumulative value is set to zero, and only the cumulative values ​​of the first to fourth scores are used as the current score cumulative value, then each execution Figure 4 The flowchart can use the accumulated score value to detect congestion in the form of instantaneous value.

[0069] exist Figure 5In the controller 80, the received score cumulative value of this time is stored in the communication receiving buffer, and the score cumulative value of this time is set as an input of the comparison / estimation unit 71.

[0070] As another input to the comparison / estimation unit 71, Figure 1 to Figure 3 The exhaust pressure measured value of the exhaust pressure sensor 60 in.

[0071] The comparison / estimation unit 71 performs Figure 4 The processing of steps S11 and S12 combines the current score accumulation value and the exhaust pressure measurement value, compares the combination with the threshold values ​​a1, a2, a3, and b1, thereby estimating the location of the blockage, and outputs it to the display screen 81 of the controller 80, for example. It should be noted that the current score accumulation value can be output to the display screen 81 separately and independently. As described above, the output of the comparison / estimation unit 71 and the current score accumulation value can be sent to the outside as digital data, or recorded in various recording media such as a USB memory and a memory card.

[0072] Figure 5 The display screen 81 shown is an example of estimating and displaying which quadrant the combination of the current score accumulation value and the exhaust pressure measurement value belongs to among the four quadrants defined by threshold values ​​a1, a2, b1, etc. For example, a1 is a threshold value corresponding to the lower limit value of the exhaust pressure, a2 is a threshold value for warning of an increase in the exhaust pressure, and a3 is a threshold value corresponding to the upper limit value of the exhaust pressure. It is preferred that an alarm is issued when the exhaust pressure exceeds the threshold value a3 to urge the pump to stop operating. In addition, b1 is a threshold value for warning of an increase in the current score accumulation value. Needless to say, the number, meaning (type), and display format of the display screen 81 of these threshold values ​​are not limited to the above-mentioned examples.

[0073] If the four quadrants (1) to (4) in the display screen 81 are explained, it is empirically found that the higher the exhaust pressure measurement value, the more deposits 102 there are in the exhaust side piping 43, and the larger the current score cumulative value, the more deposits 102 there are in the intake side piping 42.

[0074] Taking this into consideration, quadrant (1) is set as the area where the deposits 102 are large in the intake side piping 42 and the exhaust side piping 43, quadrant (2) is set as the area where the deposits 102 are large in the intake side piping 42, and quadrant (3) is set as the area where the deposits 102 are large in the exhaust side piping 43, and the combination of the current score accumulation value and the exhaust pressure measurement value is classified in any of these quadrants (1), (2), and (3) and displayed by a diagram or the like. Quadrant (4) is an example where the deposits 102 are small in the intake side piping 42 and the exhaust side piping 43, and is usually not displayed by a diagram or the like, but in the case where impurities are bitten into the impeller 41, etc., this quadrant (4) can be used to display an abnormality alarm.

[0075] As described above, in the embodiment of the present invention, the presence or absence of current limiting action, overcurrent limiting action, and overcurrent protection action is converted into a score, and the cumulative value of these scores is combined with, for example, the exhaust pressure measurement value, so that the blockage occurrence location of the intake side piping 42, the impeller 41, the exhaust side piping 43, etc. can be estimated and output. As a result, the inspection / cleaning operation when the blockage occurs can be performed quickly and accurately, making it possible to improve the efficiency of maintenance operations of various pumps such as vacuum pumps.

[0076] <Industrial Applicability>

[0077] The present invention can be used in various pumps as fluid machinery for sucking or pressurizing fluids such as gas and liquid to detect blockage of fluid flow paths caused by reaction products, impurities, etc.

[0078] Description of Reference Numerals

[0079] 10: Power supply

[0080] 20: Power conversion device

[0081] 30: Electric Motor

[0082] 40: Vacuum pump

[0083] 41: Impeller

[0084] 42: Intake side piping

[0085] 43: Exhaust side piping

[0086] 50: Chamber (furnace)

[0087] 60: Exhaust pressure sensor

[0088] 70: Blockage detection unit

[0089] 71: Comparison / Estimation Unit

[0090] 80: Controller

[0091] 81: Display screen

[0092] 101: Spawn

[0093] 102: Accumulation

Claims

1. A pump blockage detection system, comprising: a motor controlled by a power conversion device; and a pump driven by the motor for pressurizing or pumping a fluid, wherein a blockage detection system of the pump detects blockage of a fluid flow path constituting the pump, The blockage detection unit provided in the control unit of the above-mentioned power conversion device includes: a first function for setting a first score according to the presence or absence of a current limiting action, an output torque limiting action, or an output power limiting action on the motor when the motor is overloaded due to the blockage and the current of the motor increases; A second function is to set a second score according to whether or not an overcurrent limiting action is performed on the motor; A third function is to set a third score according to the presence or absence of an overcurrent protection action for removing the overcurrent of the motor; as well as The fourth function sets a fourth score according to whether the overcurrent protection action is performed when the motor is started. The blockage is detected based on one or more of the first to third scores and the fourth score.

2. The pump blockage detection system according to claim 1, wherein: The congestion detection unit detects the congestion based on a score cumulative value obtained by adding a plurality of the scores.

3. The pump blockage detection system according to claim 1 or 2, wherein: The first score is calculated based on the amount of reduction in the output frequency of the power conversion device.

4. The pump blockage detection system according to claim 2, wherein: The clogging detection unit detects the clogging based on the score cumulative value and a pressure measurement value of a pressure sensor disposed in the fluid flow path.

5. The pump blockage detection system according to claim 4, wherein: The clogging detection unit includes a fifth function of comparing a combination of the score cumulative value and the pressure measurement value with a predetermined threshold value to estimate a location where the clogging has occurred and outputting the result.

6. The pump blockage detection system according to claim 5, wherein: The score accumulation value calculated in this calculation cycle is set as the current score accumulation value, and a combination of the current score accumulation value and the pressure measurement value is compared with a predetermined threshold value, thereby estimating the occurrence site of the blockage.

7. The pump blockage detection system according to claim 5, wherein: The above-mentioned score cumulative value calculated through the previous operation cycle is set as the previous score cumulative value, the above-mentioned score cumulative value and the cumulative values ​​of multiple scores in this operation cycle are added to obtain the current score cumulative value, and the combination of the above-mentioned current score cumulative value and the above-mentioned pressure measurement value is compared with a specified threshold value to infer the location where the above-mentioned blockage occurs.

8. The pump blockage detection system according to claim 5, wherein: The location where the blockage is estimated by the fifth function is displayed on a display screen, or is sent to the outside via a network, or is recorded in a recording medium.

9. The pump blockage detection system according to claim 6, wherein: The above-mentioned cumulative score value is displayed on the display screen, or sent to the outside through the network, or recorded in a recording medium.

10. The pump blockage detection system according to claim 1 or 2, wherein: The pump is a vacuum pump, and the fluid flow path is an exhaust side pipe or an intake side pipe of the vacuum pump.

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