JP2023092082A - Wear detection system and wear detection method - Google Patents

Abstract

To provide a wear detection system and a wear detection method which can securely detect, with a simple configuration, wear of a vane wheel of a turbo machine.SOLUTION: A wear detection system 8 detects wear of a vane wheel 3 of a turbo machine provided with: a rotatably supported main shaft 2; the vane wheel 3 attached to one end of the main shaft 2 and having a plurality of vanes 31; and a casing 7 which accommodates the main shaft 2 and the vane wheel 3. The wear detection system comprises: a load acquisition unit 83 which acquires a thrust load acting on the main shaft 2; a flow rate acquisition unit which acquires flow rate of fluid flowing in the casing 7; and an estimation unit which estimates a gap between tip parts of the vanes 31 and an inner wall surface of the casing 7 by using the thrust load acquired by the load acquisition unit 83 and the flow rate acquired by the flow rate acquisition unit, and estimates a wear state of the vane wheel 31 on the basis of the gap.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wear detection system and a wear detection method for detecting wear of an impeller of a turbomachine.

In turbomachinery, it is known that impellers wear due to collisions with solid particles inevitably contained in the working fluid. In order to prevent deterioration of turbomachinery performance due to progress of wear, it is necessary to detect wear and repair or replace the impeller.

As a method to detect impeller wear, a wear detection piece made of a material similar to that of the impeller is installed in the piping of the turbomachine, and the elastic vibration wave generated by the wear of the wear detection piece due to collision with solid particles is detected. It has been proposed to detect the wear of the impeller by detecting it (Patent Document 1).

JP-A-62-232532

In the technique disclosed in Patent Literature 1, the wear detecting piece is supported in a cantilevered state penetrating the pipe wall. In this case, the wear detection piece exposed to the working fluid flowing in the pipe may be fatigued and damaged by fluid vibration, making it impossible to detect wear. There were also concerns about leaks.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wear detection system and a wear detection method that can reliably detect wear of an impeller of a turbomachine with a simpler configuration.

A wear detection system according to the present invention for achieving the above object comprises a main shaft rotatably supported, an impeller attached to one end of the main shaft and having a plurality of blades, the main shaft and the impeller. A wear detection system for detecting wear of an impeller of a turbomachine provided with a housing housing the impeller, comprising: a load acquisition unit that acquires a thrust load acting on the main shaft; and a flow rate of fluid that flows through the casing. estimating the gap between the tip of the blade and the inner wall surface of the casing based on the thrust load acquired by the load acquisition unit and the flow rate acquired by the flow acquisition unit; and an estimating unit for estimating the state of wear of the impeller based on the clearance.

In a turbomachine, as the wear of the impeller progresses due to collision with solid particles contained in the working fluid, the gap between the tip of the blade and the inner wall surface of the casing increases. Turbomachinery is normally operated so that the flow rate of the working fluid remains constant. In this case, as the gap widens, the amount of working fluid returned to the suction side increases and the pressure between the suction side and the discharge side increases. Since the difference is reduced, the thrust load acting on the main shaft from the impeller to the suction side is reduced. In other words, the fact that the thrust load decreases when the flow rate is constant means that the gap is widening and therefore impeller wear is progressing.

In the above configuration, by acquiring the flow rate and thrust load over time, it is possible to monitor changes in the thrust load at a constant flow rate. As a result, it was estimated that the gap between the tip of the blade and the inner wall surface of the casing had expanded because the thrust load at a constant flow rate had decreased over a predetermined period of time. It can be presumed to be in progress. That is, according to the above configuration, it is possible to detect that the wear of the impeller is progressing. Further, since there is a correlation between the degree of expansion of the gap and the degree of reduction in the thrust load, the degree of expansion of the gap can be estimated from the degree of reduction in the thrust load, and the degree of wear of the impeller can be estimated based on this. . That is, according to the above configuration, it is also possible to detect the progress of wear of the impeller.

In addition, since the above configuration does not require installation of the wear detection member penetrating the casing, there is no concern that the wear detection member will be damaged, the strength of the casing will be reduced, or the working fluid will leak. can be detected.

In the wear detection system according to the present invention, it is preferable that the estimator estimates the gap using information indicating the relation between the thrust load and the flow rate prepared in advance and the gap.

According to the above configuration, the estimation unit can quantitatively estimate the gap corresponding to the thrust load acquired by the load acquisition unit, and as a result, the degree of wear of the impeller can be estimated more accurately. becomes possible.

The wear detection system according to the present invention further includes a rotation speed acquisition unit that acquires the rotation speed of the main shaft, and the flow rate acquisition unit has a correlation between the thrust load and the rotation speed prepared in advance and the flow rate. It is preferable to acquire the flow rate based on the thrust load acquired by the load acquisition unit and the rotation speed acquired by the rotation speed acquisition unit, using the information indicating .

Turbomachinery can be difficult to install a flow meter due to space constraints, especially if the casing size is large. According to the above configuration, it is possible to obtain the flow rate from the thrust load and the rotation speed without using a flow meter.

In the wear detection system according to the present invention, the main shaft is supported by a bearing that is housed in a bearing box and receives a thrust load acting on the main shaft, and the load acquisition section acts on the bearing box via the bearing. Preferably, a load cell is included to measure the applied thrust load.

According to the above configuration, the thrust load acting on the main shaft can be measured by an inexpensive and highly accurate load cell.

In the wear detection system according to the present invention, it is preferable that a plurality of load cells be provided at regular intervals in the circumferential direction of the main shaft.

According to the above configuration, since the thrust load acting on the main shaft is evenly transmitted to the plurality of load cells, more accurate measurement is possible.

The wear detection system according to the present invention preferably further includes a notification unit that issues an alarm when the clearance estimated by the estimation unit reaches a previously prepared threshold value for the clearance.

According to the above configuration, a threshold value is set in advance for the gap that requires replacement or repair of the impeller, and when the gap estimated by the estimation unit reaches the threshold value, an alarm is issued to prompt the worker to replace or repair the impeller. , the performance of the turbomachinery can be properly maintained.

A wear detection method according to the present invention for achieving the above object comprises a main shaft rotatably supported, an impeller attached to one end of the main shaft and having a plurality of blades, and the main shaft and the impeller. A wear detection method for detecting wear of an impeller of a turbomachine provided with a housing housing the impeller, comprising: a load acquiring step of acquiring a thrust load acting on the main shaft along a direction toward the impeller; a flow rate obtaining step of obtaining the flow rate of the fluid flowing in the casing, and the thrust load obtained in the load obtaining step and the flow rate obtained in the flow rate obtaining step are used to determine the tip portion of the blade and the inner wall surface of the casing. and an estimating step of estimating a gap between and estimating the state of wear of the impeller based on the gap.

According to the above configuration, the gap between the tip of the blade and the inner wall surface of the casing is estimated, and based on this, it is possible to detect that the wear of the impeller is progressing and the progress of the wear of the impeller. can be done.

It is a figure which shows roughly the structure of the vertical shaft mixed flow pump which is an example of a turbo machine. FIG. 2 is a diagram schematically showing a configuration around a suction bell of the mixed flow pump shown in FIG. 1; 1 is a block diagram showing the configuration of a wear detection system according to the present invention; FIG. FIG. 4 is a diagram showing the relationship between thrust load, flow rate, and gap; FIG. 4 is a block diagram showing another embodiment of a wear detection system according to the present invention;

Hereinafter, the wear detection system and the wear detection method of the present invention for detecting wear of the impeller of the turbomachine will be described using a vertical shaft mixed flow pump as an example of the turbomachine. However, the wear detection system and wear detection method according to the present invention can be applied to any turbomachine in which a thrust load acts on the main shaft due to the rotation of the impeller. For example, it can be applied to pumps other than vertical shaft mixed flow pumps (horizontal shaft type pumps, DC pumps, etc.), and can also be applied to turbo machines other than pumps (turbines, fans, jet engines, etc.).

[Construction of Vertical Shaft Mixed Flow Pump]
A vertical shaft mixed flow pump 1 includes a main shaft 2 extending substantially vertically, an impeller 3 attached to the lower end of the main shaft 2, and a guide vane boss 4 disposed above the impeller 3 and into which the main shaft 2 is inserted. , a plurality of guide vanes 5 provided on the outer circumference of the guide vane boss 4, a drive source 6 for driving the main shaft 2, and a tubular pump casing housing the main shaft 2, the impeller 3, the guide vane boss 4, and the guide vanes 5. 7.

The pump casing 7 is configured by connecting a suction bell 71, a discharge bowl 72, and a discharge pipe 73 in order from bottom to top. The lower end 21 of the main shaft 2 extends to the vicinity of the upper portion of the suction bell 71 , and the impeller 3 attached to the lower end 21 of the main shaft 2 is positioned between the tip 311 of the blade 31 and the inner wall surface 711 of the suction bell 71 . It is surrounded by the upper part of the suction bell 71 and the lower part of the discharge bowl 72 with a predetermined gap g. The guide vane boss 4 is housed in the discharge bowl 72 and fixed to the discharge bowl 72 via the guide vane 5 . An upper end 22 of the main shaft 2 extends upward through a discharge pipe 73 and is connected to an electric motor and a speed reducer as an example of the drive source 6 .

The spindle 2 is rotatably supported by a bearing 23 in the vicinity of the lower end 21 . In this embodiment, the bearing 23 is a bearing that receives the radial load acting on the main shaft 2, and is provided in the through hole of the discharge bowl 72 into which the main shaft 2 is inserted. A ceramic bearing can be used as an example of the bearing 23 .

Further, the main shaft 2 is rotatably supported by bearings 24 in the vicinity of the upper end 22 . A thrust load including the weight of the main shaft 2, the impeller 3, etc., and the force toward the suction side generated by the rotation of the impeller 3 acts on the main shaft 2. As shown in FIG. In this embodiment, the bearing 24 is a bearing that receives a radial load and a thrust load, and as an example, a double thrust angular contact ball bearing can be used. The bearing 24 is housed in a bearing box 25, and the bearing box 25 is mounted and supported on the bearing base 26 via a flange 251 projecting from the outer peripheral surface.

When the main shaft 2 is rotated by the drive source 6 , the impeller 3 rotates, and the working fluid in the pump well is sucked from the suction bell 71 , rectified by the guide vanes 5 in the discharge bowl 72 , and then discharged to the discharge pipe 73 . expelled from

[Configuration of wear detection system (first embodiment)]
In the first embodiment, the wear detection system 8 estimates the wear state of the impeller 3 based on the operating state of the vertical shaft mixed flow pump 1, and includes a control unit 81, a flow rate acquisition unit 82, a load acquisition unit A section 83 and a notification section 84 are provided.

The flow rate acquiring unit 82 acquires the flow rate as data relating to the operating state of the vertical shaft mixed flow pump 1 and transmits it as a signal to the control unit 81 (corresponding to the flow rate acquiring step in the present invention). In this embodiment, the flow rate acquisition unit 82 is configured by a flow meter (not shown) that measures the flow rate of the working fluid flowing through the vertical shaft mixed flow pump 1 . As the flowmeter, an ultrasonic flowmeter, an electromagnetic flowmeter, a bend flowmeter, or the like can be used.

The load acquisition unit 83 acquires the thrust load as data relating to the operating state of the vertical shaft mixed flow pump 1 and transmits it as a signal to the control unit 81 (corresponding to the thrust load acquisition step in the present invention). In this embodiment, the load cell is arranged between the flange 251 of the bearing housing 25 and the bearing base 26 . The thrust load acting on the main shaft 2 acts on the bearing housing 25 via the bearing 24 , and the load cell measures the thrust load acting on the bearing housing 25 and acquires it as the thrust load acting on the main shaft 2 . From the viewpoint of improving measurement accuracy, three load cells are provided at equal intervals in the circumferential direction of the main shaft 2 , and the measured values of these load cells are summed up to obtain the thrust load of the main shaft 2 . However, the number of load cells is not limited to this, and may be two or less, or may be four or more.

The control unit 81 controls the operation of the wear detection system 8 and includes a processor such as a CPU functioning as an estimating unit 811 and a storage device such as a memory or hard disk functioning as a storage unit 812 . A program for implementing the operation of the wear detection system 8 is stored in the storage unit 812, and the estimation unit 811 is implemented by executing the program.

A signal indicating the flow rate acquired by the flow rate acquisition section 82 and the thrust load acquired by the load acquisition section 83 is transmitted to the estimation section 811 . The estimating unit 811 estimates the gap g between the tip portion 311 of the blade 31 of the impeller 3 and the inner wall surface 711 of the suction bell 71 from the received flow rate and thrust load, and based on the estimated gap g Estimate the wear state of the car (corresponding to the estimation step in the present invention).

Specifically, when the wear of the impeller 3 progresses due to the collision with solid particles contained in the working fluid, the gap g between the tip portion 311 of the blade 31 and the inner wall surface 711 of the suction bell 71 becomes large. However, the gap g, the flow rate of the vertical shaft mixed flow pump 1, and the thrust load acting on the main shaft 2, as shown in FIG. There is a correlation that the thrust load decreases with increasing pressure. Therefore, in the vertical shaft mixed flow pump 1, which is normally operated so that the flow rate is constant, the decrease in the thrust load during operation means that the gap g is expanding, that is, the wear of the impeller 3 is progressing. It means that there is

Therefore, the control unit 81 acquires the thrust load at the initial stage of operation of the vertical shaft mixed flow pump 1 in which the impeller 3 is not worn, and continuously or periodically acquires the thrust load after the initial stage of operation. It controls the load acquisition unit 83 . Then, the estimating unit 811 estimates that the gap g is expanding when the thrust load corresponding to the flow rate acquired by the flow rate acquiring unit 82 decreases over an arbitrary predetermined period from the beginning of the operation, and the impeller Assume that 3 wear is ongoing. Further, the estimating unit 811 calculates the degree of reduction of the thrust load over an arbitrary predetermined period from the start of operation, and uses a predetermined correlation stored in advance in the storage unit 812 to estimate the degree of expansion of the gap. You may estimate the abrasion degree of the impeller 3 based on.

Alternatively, the storage unit 812 stores information indicating the correlation as shown in FIG. The clearance g is quantitatively estimated from the thrust load at an arbitrary timing acquired by the unit 83, and whether or not wear is progressing or the degree of wear is estimated based on the estimated clearance g. The correlation can be obtained in advance through experiments or the like.

Further, the estimating unit 811 uses the threshold value for the gap g that requires replacement or repair of the impeller, which is stored in advance in the storage unit 812, based on the result of estimating the wear state. It determines whether or not replacement or repair is necessary, and transmits the determination result as a signal to the notification unit 84 . Specifically, the estimating unit 811 compares the degree of expansion of the gap g estimated from the degree of reduction of the thrust load with a threshold for the degree of expansion of the gap g, and when the estimated degree of expansion of the gap g reaches the threshold Then, it is determined that the impeller needs to be replaced or repaired. Alternatively, the estimating unit 811 compares the gap g quantitatively estimated from the flow rate and the thrust load using the correlation with a threshold value for the gap g, and when the estimated gap g reaches the threshold value, the impeller It is determined that replacement or repair is necessary.

The reporting unit 84 outputs an alarm according to the signal received from the estimating unit 811 and indicating the result of determination that the impeller needs to be replaced or repaired. encourage As the notification unit 84, a known device that outputs an alarm by sound, light, color, text, or a combination thereof can be used. Furthermore, the notification unit 84 receives a signal indicating at least one of the flow rate acquired by the flow rate acquisition unit 82, the thrust load acquired by the load acquisition unit 83, and the gap g estimated by the estimation unit 811. It may be configured to notify.

[Configuration of Wear Detection System (Second Embodiment)]
In the second embodiment, the wear detection system 8 includes a control unit 81, a load acquisition unit 83, a notification unit 84, and a rotation speed acquisition unit 85. The control unit 81 includes an estimation unit 811 and a flow rate acquisition unit. 813, and a storage device such as a memory or a hard disk that functions as the storage unit 812. FIG.

In this embodiment, instead of measuring the flow rate of the vertical shaft mixed flow pump 1 necessary for estimating the gap g by the estimating unit 811 with a flow meter, the thrust load acquired by the load acquiring unit 83 and the rotation speed acquiring unit 85 It is different from the first embodiment in that it is configured to obtain the number of rotations obtained by . Configurations different from the first embodiment will be described below. Descriptions of the load acquisition unit 83, the notification unit 84, and the like, which have the same configurations as those described in the first embodiment, are omitted to avoid complication.

The rotation speed acquisition unit 85 acquires the rotation speed of the main shaft 2 as data relating to the operating state of the vertical shaft mixed flow pump 1 and transmits it to the control unit 81 as a signal. In this embodiment, the rotational speed acquisition unit 85 is configured by a tachometer (not shown) that measures the rotational speed of the spindle 2 . A known contact type or non-contact type tachometer can be used as the tachometer.

Information (formula, model, graph, etc.) indicating the correlation between the rotation speed of the main shaft 2 and the thrust load acting on the main shaft 2 and the flow rate of the vertical shaft mixed flow pump 1 is stored in the storage unit 812 in advance. The relationship can be obtained, for example, by performing multiple regression analysis with the number of revolutions and the thrust load as explanatory variables and the flow rate as the objective variable. Using this correlation, the estimation unit 811 estimates the flow rate of the vertical shaft mixed flow pump 1 based on the thrust load acquired by the load acquisition unit 83 and the rotation speed acquired by the rotation speed acquisition unit 85 . Then, the estimation unit 811 estimates the gap g as described in the first embodiment using the estimated flow rate, and estimates the wear state based on the gap g.

1: vertical shaft mixed flow pump 2: main shaft 21: lower end 22: upper end 23: bearing 24: bearing 25: bearing housing 251: flange 26: bearing base 3: impeller 31: vane 311: tip portion 4: guide vane boss 5: Guide vane 6 : Drive source 7 : Pump casing 71 : Suction bell 711 : Inner wall surface 72 : Discharge bowl 73 : Discharge pipe 8 : Wear detection system 81 : Control unit 811 : Estimation unit 812 : Storage unit 813 : Flow rate acquisition unit 82 : Flow rate acquisition unit 83 : Load acquisition unit 84 : Notification unit 85 : Rotation speed acquisition unit g : Gap

Claims (7)

Detecting wear of an impeller of a turbomachine comprising a main shaft rotatably supported, an impeller attached to one end of the main shaft and having a plurality of blades, and a casing housing the main shaft and the impeller A wear detection system for
a load acquisition unit that acquires a thrust load acting on the main shaft;
a flow rate acquisition unit that acquires the flow rate of the fluid flowing through the casing;
A gap between the tip of the blade and the inner wall surface of the casing is estimated from the thrust load acquired by the load acquisition unit and the flow rate acquired by the flow acquisition unit, and the blade is based on the gap. and an estimator for estimating the state of wear of the vehicle. 2. The wear detection system according to claim 1, wherein said estimating unit estimates said gap using information indicating a correlation between said thrust load and said flow rate prepared in advance and said gap. further comprising a rotation speed acquisition unit that acquires the rotation speed of the main shaft;
The flow rate acquisition unit obtains the thrust load and the rotation speed acquired by the load acquisition unit using information indicating the correlation between the thrust load and the rotation speed prepared in advance and the flow rate. The wear detection system according to claim 1 or 2, wherein the flow rate is obtained from the obtained rotational speed. The main shaft is supported by bearings housed in a bearing housing and receiving a thrust load acting on the main shaft,
The wear detection system according to any one of claims 1 to 3, wherein the load acquisition section includes a load cell that measures a thrust load acting on the bearing housing via the bearing. 5. The wear detection system according to claim 4, wherein a plurality of said load cells are provided at equal intervals in the circumferential direction of said main shaft. 6. The wear according to any one of claims 1 to 5, further comprising a notification unit that issues an alarm in response to the gap estimated by the estimation unit reaching a previously prepared threshold value for the gap. detection system. Detecting wear of an impeller of a turbomachine comprising a main shaft rotatably supported, an impeller attached to one end of the main shaft and having a plurality of blades, and a casing housing the main shaft and the impeller A wear detection method for
a load acquiring step of acquiring a thrust load acting on the main shaft along a direction toward the impeller;
a flow rate obtaining step of obtaining the flow rate of the fluid flowing through the casing;
Based on the thrust load obtained in the load obtaining step and the flow rate obtained in the flow rate obtaining step, the gap between the tip of the blade and the inner wall surface of the casing is estimated, and the blade is based on the gap. and an estimating step of estimating the wear state of the wear detection method.

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