JP2002181525A - Device for measuring interval of impeller for pump and anomaly determining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for measuring the interval of an impeller for a pump capable of accurate non-contact measurement on the interval between the impeller for a pump and a casing and an anomaly determining method. SOLUTION: An eddy current ammeter sensor 2 as a non-contact-type range finder is mounted to an interval detecting section of the casing 11, and changes in the interval between the casing 11 and an edge part of a blade part 16 are detected by the eddy current ammeter sensor 2 from changes in generated eddy current. As it is possible to directly and accurately monitor the changes in the interval, it is possible to avoid serious damage due to contacts between the casing 11 and the blade part 16. In addition, as it is possible to eliminate unexpected maintenance work and execute maintenance work as planned with a substantial increase in reliability in the detection of changes in the interval, it is possible to substantially reduce maintenance cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump impeller distance measuring device which is mounted on a casing provided with a rotatable impeller, and measures the distance between the casing and the impeller. It relates to the judgment method.

[0002]

BACKGROUND ART Vertical pumps are used to pump water and other liquids. This vertical pump is structurally
Since the pumping part (suction part) is in the liquid to be pumped, problems such as wear of the bearing part are monitored indirectly through vibrations transmitted to the ground. The final determination of the presence or absence of a failure is made by lifting and disassembling the pump. Therefore, the disassembly time of the pump needs to be short, and after the disassembly time, secondary damage may increase. To perform an overhaul,
The need for large heavy equipment has increased the labor and cost.

In order to eliminate these disadvantages, conventionally,
There is a technique disclosed in Japanese Patent Application Laid-Open No. 9-292216. In this technology, an access hole is drilled in a protector (casing) that covers the impeller of a vertical mixed-flow pump immersed in a water absorption layer, and an access pipe connected to the access hole is guided to the outside of the water absorption layer. Insert the endoscope into the access hole from the access tube, keep the distance from the tip of the endoscope to the impeller constant, measure the exit diameter of the access hole that appears on the image of the endoscope, The distance from the end of the endoscope to the exit of the access hole is converted from the exit diameter of the endoscope, and the distance from the end of the endoscope to the access hole, the distance from the end of the endoscope to the impeller, and the impeller The gap with the protector is calculated.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. 9-2922
In the conventional example of No. 16, the impeller and protector (casing)
Is measured, but the pump must be stopped at the time of measurement. The dimensions of the impeller are different from those of the protector at the time of rotation and at the time of stop. In the conventional example, since the operating state cannot be measured, the measurement is not always performed accurately. Also, because the casing of the vertical pump is submerged in the liquid, the impeller swings due to wear of the bearing, or the impeller falls due to the play of the joint etc., and the impeller comes into contact with the casing. However, indirect detection by vibration or the like has a large attenuation during the propagation of vibration, making it difficult to make a clear judgment.

Further, it is considered to measure the shaft runout and the amount of movement with an axis moving meter. Although the structure of these sensors is available for lubricating oil or underwater, it is necessary to pass through a double casing to measure the shaft runout of the vertical pump to which the present invention relates. Cannot be installed with the current structure.

An object of the present invention is to provide a pump impeller distance measuring device capable of accurately measuring the distance between a pump impeller and a casing in a non-contact manner. Another object of the present invention is to provide a method for determining an abnormality of a pump impeller that can accurately determine an abnormality of a pump impeller in a non-contact manner.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to achieve the above object by directly measuring the distance between a casing and an impeller in a non-contact manner using a non-contact type distance meter. . Specifically, the pump impeller interval measuring device of the present invention is a device for measuring an interval between the casing and the impeller of a pump in which an impeller is rotatably provided in a casing. And a non-contact type distance meter attached to the casing and measuring a distance between the casing and the impeller.

In the invention having this configuration, a non-contact type distance meter is attached to the distance detecting portion, and the non-contact type distance meter detects a change in the distance between the casing and the impeller in a non-contact state. As a result, changes in the distance between the casing and the impeller can be directly and accurately monitored, so that serious damage due to contact between the casing and the impeller can be avoided. In addition, since the reliability of the detection of the change in the interval is greatly improved, the maintenance work can be performed systematically without a sudden maintenance work, so that the maintenance cost can be significantly reduced.

Here, in the present invention, it is preferable that the non-contact type distance meter is an eddy current sensor. With this configuration, the distance between the casing and the impeller can be detected by using a known eddy current sensor, so that the structure of the device can be simplified. Further, in the present invention, the impeller includes a shaft portion and a blade portion, and an inner peripheral surface of a casing to which the eddy current sensor is attached, and a tip end edge of the blade portion facing the inner peripheral surface, the shaft portion. It is preferable to have a configuration formed so as to be inclined with respect to the axial direction. This inclination angle α is preferably 45 °. With this configuration, even when the impeller is displaced only in the axial direction of the shaft portion, a change in the interval with respect to the casing can be detected. Therefore, more accurate measurement is possible.

Further, in the present invention, the pump is preferably a vertical centrifugal pump. With this configuration, it is possible to provide a vertical centrifugal pump in which the reliability of detecting a change in the interval is greatly improved.

Further, according to the method for judging abnormality of a pump impeller of the present invention, an eddy current is generated from an eddy current sensor mounted on the casing toward the impeller, and the impeller is generated based on a waveform of the eddy current sensor. It is characterized by detecting abnormality of a car.

In the invention having this configuration, a change in the interval between the casing and the impeller is detected in a non-contact state based on the waveform of the eddy current generated by the eddy current sensor, and this is compared with a normal waveform. By analyzing it, the abnormality of the impeller is accurately determined. Therefore, serious damage due to contact between the casing and the impeller can be avoided, and unexpected maintenance work can be eliminated and maintenance work can be performed systematically.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 show a first embodiment of the present invention. 1, the vertical pump 1 is provided with an eddy current sensor 2 which is a non-contact type distance meter. The vertical pump 1 is a vertical centrifugal pump and has a structure including a shaft 3. The upper end of the shaft 3 is connected to an electric motor 5 through an elbow 4 disposed between a vertically extending pumping pipe 6 and a horizontally extending pumping pipe 6, and the electric motor 5 rotates the shaft 3. It can be driven. An inner cylinder 3A is provided inside the pumping pipe 6, and the shaft 3 is arranged inside the inner cylinder 3A. A casing 11 is provided at a lower end of the pumping pipe 6, and an impeller 9 connected to the shaft 3 is rotatably arranged inside the casing 11. The eddy current sensor 2 is a device that measures the distance between the casing 11 and the impeller 9 and is attached to the casing 11.

FIG. 2 shows an enlarged view of the vicinity of the casing 11 to which the eddy current sensor 2 is attached. The impeller 9 has a configuration in which a shaft portion 15 and a blade portion 16 are connected to each other via a shaft 3 and a bearing 3 </ b> B, and a tip end portion of the blade portion 16 is exposed to an internal space of the casing 11. It is. The tangent to the inner peripheral surface 11S of the casing 11 to which the eddy current sensor 2 is attached, and the leading edge 1 of the blade 16 facing the inner peripheral surface 11S.
The tangent line 6E is inclined with respect to the longitudinal axis X of the shaft portion 15. Therefore, the longitudinal axis of the eddy current sensor 2 is also configured to form an inclination angle α between the inner peripheral surface 11S and the blade portion 16 corresponding to the inclination angle between the blade portion 16 and the inner peripheral surface 11S.

The eddy current meter sensor 2 is configured to generate an eddy current when a high-frequency current flows through a coil (not shown) provided therein. When the interval T changes, the impedance changes and the current changes. The change in the interval T is detected based on the change in the current. The control means 12 receives a signal from the eddy current sensor 2 and calculates an interval T between the casing 11 and the impeller 9 based on the signal, and the calculation means 12A
And a display means 12B for displaying the result calculated by the display on a display or the like as necessary.

The detection result of the eddy current meter sensor 2 will be described in detail with reference to the graph of FIG. In the graph of FIG.
The vertical axis indicates the radial displacement of the impeller 9, and the horizontal axis indicates time (t). If the interval T between the inner peripheral surface 11S of the casing 11 and the leading edge 16E of the blade 16 facing the inner peripheral surface 11S is kept constant, a waveform as shown in FIG. The interval T between the apex P of each triangular waveform and the dotted line K indicating the inner peripheral surface of the casing 11 is substantially constant.

In this impeller 9, after a predetermined period of time, thrust movement (downward) of the shaft system occurs, or the outer periphery of the impeller 9 is corroded and the peripheral speed of the impeller 9 decreases. This causes an increase in friction loss due to overall corrosion of the impeller 9 and the casing 11, and a decrease in efficiency of the vertical pump due to a decrease in pumping capacity. When thrust movement (downward) of the shaft system occurs, the interval T between the inner peripheral surface 11S of the casing 11 and the leading edge 16E of the blade 16 facing the inner peripheral surface 11S becomes narrower, and FIG. A waveform as shown in B) occurs. In this waveform, the interval T between the vertex P of each triangular waveform and the dotted line K indicating the inner peripheral surface of the casing 11 is displayed narrower than that shown in FIG.

Further, due to the runout (lateral direction) of the impeller due to wear of the bearing or the like, the inner peripheral surface 11S of the casing 11
The tip edge 16E of the blade 16 facing the inner peripheral surface 11S
When the space T becomes narrow or wide in some places due to the above-described cause, the state shown in FIG.
A waveform as shown in (C) is obtained, and this waveform indicates that the interval is not constant but irregular. Also,
When an abnormality occurs in the impeller 9 due to a part of the blade portion 16 missing or the like, a waveform as shown in FIG. 3D is obtained, and the interval between the waveforms is normal as shown in FIG. It is shown that t2 is wider than value t1. In FIG. 3 (D), a chevron portion indicated by a wavy line is a missing portion of the blade 16. From these, the degree and position of the missing blade can be determined. 3 (B), 3 (C), 3
When the waveform as shown in (D) occurs, the pump is pulled up and maintenance and repair of necessary parts are performed.

Therefore, according to the first embodiment, the following operation and effect can be obtained. (1) A non-contact type distance meter is attached to the interval detection portion of the casing 11, and the casing 11 and the blade 16
Is detected, the change in the interval T can be directly and accurately monitored, and serious damage is avoided by the contact between the casing 11 and the blade 16. it can. (2) Since the non-contact type distance meter is a known eddy current sensor 2, the distance between the casing 11 and the edge E of the blade 16 is changed by the change of the eddy current generated by the eddy current sensor 2. The change in T can be accurately detected with a simple structure. (3) As the reliability of detecting a change in the interval T is greatly improved, unexpected maintenance work can be eliminated and the maintenance work can be executed systematically, so that maintenance costs can be significantly reduced. .

(4) The blade 16 is composed of the shaft 15 and the blade 16
And an inner peripheral surface 11S of the casing 11 to which the eddy current sensor 2 is attached.
Is formed at an angle of 45 ° with respect to the axial direction of the shaft, so that even if the impeller 9 is displaced only in the axial direction of the shaft 15, 11 can be detected. Therefore, more accurate measurement is possible.

(5) Since the pump is a vertical centrifugal pump, it is possible to provide a vertical centrifugal pump in which the reliability of detecting a change in the interval T is greatly improved. (6) Since an eddy current is generated from the eddy current sensor 2 attached to the casing 11 toward the impeller 9 and an abnormality such as a defect of the impeller 9 is detected by the waveform of the eddy current sensor 2, the eddy current meter By detecting the change in the distance between the casing 11 and the impeller 9 in a non-contact state based on the waveform of the eddy current generated by the sensor 2 and comparing the detected change with a normal waveform, the impeller is analyzed. 9 can be accurately determined.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the blade 16
Is different from the configuration of the first embodiment in that it is a closed type impeller 29 whose tip is covered. The other configuration is the same as that of the first embodiment. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description is omitted or simplified. The second embodiment has the basic configuration of the pump shown in FIG. 1, and the vicinity of the casing 11 to which the eddy current sensor 2 is attached is shown in detail in FIG.

In FIG. 4, the impeller 29 has a shaft 3
This is a closed-type structure including a shaft portion 15 connected to the shaft via a bearing 3B, a plurality of blade portions 16, and a cover portion 16A connecting the tips of the blade portions 16 to each other. Casing 11 to which eddy current sensor 2 is attached
The tangent to the inner peripheral surface 11S and the tangent to the tip edge 16E of the cover 16A facing the inner peripheral surface 11S are inclined with respect to the axis X in the longitudinal direction of the shaft 15. Therefore, the longitudinal axis of the eddy current meter sensor 2 is also formed so as to form the inclination angle α between the inner peripheral surface 11S and the cover portion 16A and the shaft portion 15 in accordance with the inclination angle.

The impeller 29, like the impeller 9 of the first embodiment, causes a thrust movement (downward) of the shaft system or a decrease in the peripheral speed of the impeller 29 after a predetermined period has elapsed. In addition, the friction loss is increased due to the entire corrosion of the impeller 29 and the casing 11, and the efficiency of the vertical pump is reduced due to a decrease in the pumping capacity. When thrust movement (downward) of the shaft system occurs, the inner peripheral surface 11S of the casing 11 and the inner peripheral surface 11S
The interval T between S and the opposing cover 16A is reduced,
A waveform as shown in FIG. 5B is generated. In this waveform, the interval T between the linear waveform P and the dotted line K indicating the inner peripheral surface of the casing 11 is displayed narrower than that shown in FIG.

Further, due to the runout (lateral direction) of the impeller due to wear of the bearing or the like, the inner peripheral surface 11S of the casing 11
When the interval T between the cover portion 16A and the leading edge 16E is narrowed or widened in some places due to the above-described cause, a waveform P as shown in FIG. 5C is obtained. This waveform shows that the intervals are not constant but irregular. When the waveforms as shown in FIGS. 5B and 5C are generated, the pump is pulled up and maintenance and repair of necessary parts are performed. Therefore, in the second embodiment, the same functions and effects as (1) to (5) of the first embodiment can be obtained.

The present invention is not limited to the configuration of each of the above embodiments, but includes the following modifications as long as the object of the present invention can be achieved. For example, in each of the above embodiments, it is considered that the obtained waveform differs depending on the type of the impeller used for the vertical pump, and the waveform to be monitored can be appropriately selected. Further, by going online with a monitoring system of another facility structure, centralized monitoring of the entire facility becomes possible.

In each of the above embodiments, the inner peripheral surface 11S of the casing 11 to which the eddy current meter sensor 2 is attached.
And the tip edge 16E of the blade portion facing the inner peripheral surface 11S.
Is formed at an angle of 45 ° with respect to the axial direction of the shaft portion, but in the present invention, the angle of inclination is not limited to 45 °. For example, the angle may be 30 ° or 60 °, and the inner peripheral surface 11S and the tip edge 16E of the blade facing the inner peripheral surface 11S may be parallel to the axial direction of the shaft. . Further, a plurality of eddy current meter sensors 2 may be provided. For example, the trajectories of the impellers 9 and 29 can be viewed by providing the eddy current meter sensors 2 opposite to each other by 90 degrees with respect to the impellers 9 and 29, so that more accurate measurement can be performed. Further, in the present invention, another device, for example, an ultrasonic sensor can be used as the non-contact type distance meter instead of the eddy current sensor 2.

[0028]

According to the present invention, the non-contact type distance meter is attached to the casing, and the non-contact type distance meter detects a change in the distance between the casing and the impeller. A change in the distance between the impeller can be directly and accurately monitored, and serious damage can be avoided early due to contact between the casing and the impeller. In addition, since the reliability of the detection of the change in the interval is greatly improved, the maintenance work can be performed systematically without a sudden maintenance work, so that the maintenance cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vertical pump to which a first embodiment of the present invention is applied.

FIG. 2 is an enlarged view of an eddy current meter sensor mounting portion mounted on the vertical pump of the embodiment.

FIG. 3 is a diagram illustrating a waveform generated by the eddy current meter sensor according to the first embodiment.

FIG. 4 shows a second embodiment of the present invention and is a view corresponding to FIG.

FIG. 5 is a diagram showing waveforms generated by an eddy current meter sensor according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical pump 2 Eddy current meter sensor (non-contact type distance meter) 3 Shaft 9, 29 Impeller 11 Casing 11S Inner peripheral surface 12 Control means 12A Calculation means 12B Display means 15 Shaft part 16 Blade part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F063 AA23 BA04 BD16 DA01 DA05 GA08 2F069 AA44 BB30 DD15 GG04 GG06 GG71 HH09 MM04 3H020 AA08 CA00 EA01 3H022 AA02 BA01 CA50 DA09 3H034 AA02 BB02 BB06 CC03 DD01

Claims (5)

[Claims] 1. A device for measuring a distance between the casing and the impeller of a pump having a casing in which an impeller is rotatably provided, the casing being attached to the casing and the impeller being connected to the casing. A non-contact type distance meter for measuring an interval between the pump impellers. 2. The apparatus according to claim 1, wherein said non-contact type distance meter is an eddy current meter sensor. 3. The apparatus according to claim 1, wherein the impeller includes a shaft portion and a blade portion, and an inner periphery of the casing to which the non-contact type distance meter is attached. A surface of the blade and a tip edge of the blade facing the inner peripheral surface are formed so as to be inclined with respect to an axial direction of the shaft. 4. The apparatus according to claim 1, wherein the pump is a vertical centrifugal pump. 4. The apparatus according to claim 1, wherein the pump is a vertical centrifugal pump. 5. A method for judging an abnormality of an impeller rotatably provided in a casing, comprising: generating an eddy current from an eddy current meter sensor attached to the casing toward the impeller; A method for determining abnormality of a pump impeller, wherein the abnormality of the impeller is detected by a waveform of an ammeter sensor.