JP5283868B2 - Vertical shaft pump and method of checking vertical shaft pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical shaft pump enabling the detection of the appropriate replacement period of submerged bearings for replacement by properly estimating or detecting the worn state of the submerged bearings with the pump installed and also provide a method of inspecting the vertical shaft pump. <P>SOLUTION: This vertical shaft pump comprises a rotating shaft 6, an impeller 10 secured to the rotating shaft 6, the submerged bearings 12, 15 rotatably supporting the rotating shaft 6, a casing 2 containing the impeller 10 and the submerged bearings 12, 15, and a pump base 23 for connecting the casing 2 to a pump installation floor 22. A seat 30 is installed on the outer surface of the casing 2. The seat 30 is positioned under the pump base 23 near the pump base 23. The seat 30 has a generally flat part 31a on which a vibrometer 31 for measuring the vibration of the vertical shaft pump is installed. A through hole 32 positioned above the seat 33 is formed in the pump base 23. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a vertical shaft pump for pumping liquid such as river water or drainage, and a method for checking the vertical pump.

  FIG. 1 is a schematic view showing a conventional vertical shaft pump. As shown in FIG. 1, generally, a vertical shaft pump is installed on a pump installation floor 500 at the upper part of a water tank, and a casing 506 that houses an impeller 504 is suspended via a suspension pipe 502. Such a vertical shaft pump is operated in a state where the impeller 504 and the underwater bearing 508 are immersed in water, and wear and corrosion of these members gradually occur with the passage of time of use. Therefore, the vertical shaft pump is regularly inspected to check the wear status of the bearing portion (outer bearing 510 and submerged bearing 508) and impeller 504, and the corrosion status of the casing 506, and repair or replace as necessary. It is necessary to do. Among them, damage and wear of the underwater bearing 508 cause abnormal vibrations of the pump, and eventually cause a pump failure (cannot be operated). For this reason, the inspection of the underwater bearing 508 is one of the important inspection items.

  There are two methods for checking and servicing the vertical shaft pump: 1) a method in which the pump is installed, and 2) a method in which the pump is lifted. Since the inspection method 1) does not require the pump to be pulled up, the cost is low and the inspection and maintenance period can be shortened. However, for example, the submerged bearing 508 of the vertical shaft pump is normally submerged in water, so that it is difficult to appropriately measure or detect the wear state of the submerged bearing 508 by the method 1) above. It cannot be exchanged. Even when the water in the water tank is drained and dried, the underwater bearing 508 is located above the impeller 504, so that the underwater bearing 508 cannot be inspected, maintained, or replaced. That is, even if the water in the water tank is drained and the bearing portion is exposed to the atmosphere, satisfactory inspection cannot be performed due to the problem of the installation position of the bearing.

  For this reason, vibrations of the outer bearing 510 and the pump base 514 that can be measured on the ground are measured, and the state of the underwater bearing 508 is estimated indirectly. However, in this method, since measurement is not performed near the underwater bearing 508 serving as a vibration source, it is difficult to measure abnormal vibration due to wear of the underwater bearing due to various attenuation factors up to the measurement point. The damage and wear status cannot be judged.

  In the case of a horizontal axis pump, a rotating body such as a casing or an impeller is on the floor of the machine place, and it is easy to disassemble and attach a vibration pickup etc. at an arbitrary position on the outer wall of the casing. In this case, the impeller 504, the guide vane 516, and the suspension pipe 502 are in the water tank under the floor, and the measurement position is limited to the floor. That is, sensors are attached to the outer bearing 510, the pump base 514, the prime mover 520, and the like.

  In the vertical shaft pump, the vibration of the impeller 504 and the underwater bearing 508 located in the water tank becomes less responsive as the distance from the vibration source increases. Therefore, the vibration is measured at a position away from the impeller 504 and the underwater bearing 508. However, it is difficult to reliably grasp the state of wear and damage of the underwater bearing 508 that is the vibration source. That is, at a position away from the impeller 504 and the underwater bearing 508, vibration generated in the impeller 504 and the underwater bearing 508 is easily attenuated due to the influence of the fulcrum such as the outer bearing 510 and the pump base 514. Strictly speaking, the damping effect also changes depending on how the gland packing used for the shaft seal is tightened.

  On the other hand, according to the above method 2), the wear state of the underwater bearing 508 can be appropriately measured or detected, and the underwater bearing 508 can be replaced. For this reason, in order to confirm the wear of the submerged bearing 508 of the vertical shaft pump, the method 2) has been conventionally performed.

  However, the method 2) is expensive and requires a long time for inspection and maintenance. For example, when a vertical shaft pump is lifted using an overhead crane, a mechanical engineer, an operator, a crane operator, and the like who are inspectors are required, and considerable work costs are required for the lifting. Also, lifting and reassembling a heavy pump can be a dangerous operation.

  In addition, the lifting and inspection work requires inspection and maintenance after the lifting, and then undergoes steps of re-installation, centering, and trial operation, and requires a considerable number of days. In addition, depending on the machine, it is necessary to keep the required amount of drainage at all times even during inspections and maintenance, but the pump being inspected cannot be operated during the inspection period. It is necessary to secure drainage capacity by installing it.

  The present invention has been made in view of such problems of the prior art, and can properly estimate or detect the wear state of the underwater bearing while the pump is installed, and can grasp the appropriate replacement time of the underwater bearing. It is an object of the present invention to provide a vertical shaft pump that can be used and a method for inspecting the vertical pump.

In order to achieve the above-described object, an aspect of the present invention includes a rotating shaft, an impeller fixed to the rotating shaft, an underwater bearing that rotatably supports the rotating shaft, the impeller, and the underwater A vertical shaft pump comprising a casing for housing a bearing and a pump base for connecting the casing to a pump installation floor, wherein a seat is attached to an outer surface of the casing, and the seat is located below the pump base. And the seat has a substantially flat portion on which a vibration meter for measuring the vibration of the vertical pump is installed, and the pump base has a through hole located above the seat. A hole is formed, and the vertical shaft pump includes a protective tube that guides the vibrometer from the through hole to the seat, and the seat is disposed inside the protective tube .

In a preferred aspect of the present invention, the protective tube and the through hole are connected via an elastic body.
In a preferred aspect of the present invention, the seat is a rigid body extending from an outer surface of the casing to the through hole.
A preferred aspect of the present invention further includes a natural frequency variable member whose variable natural frequency is variably configured, and the natural frequency variable member is attached to any of the casing, the pump base, and the seat. It is characterized by being.

One reference example of the present invention includes a rotating shaft, an impeller fixed to the rotating shaft, an underwater bearing that rotatably supports the rotating shaft, a casing that houses the impeller and the underwater bearing, A vertical shaft pump having a pump base connecting the casing to a pump installation floor, wherein a seat is attached to an outer surface of the casing, and the seat is below the pump base and in the vicinity of the pump base. And the seat has a substantially flat portion on which a vibrometer for measuring the vibration of the vertical shaft pump is installed, and the pump base has a through hole located above the seat, The vertical shaft pump includes a natural frequency variable member whose variable natural frequency is variably configured, and the natural frequency variable member is attached to any of the casing, the pump base, and the seat, Serial natural frequency varying member has a screw structure of the rod-like, the natural frequency of the variable member is characterized in that the length or mass is configured variably.
One reference example of the present invention is a method for inspecting a vertical pump having a rotary shaft and a submersible bearing that rotatably supports the rotary shaft, the vibration of the vertical pump being measured, and the natural frequency of the vertical pump The magnitude of the vibration in a frequency band including is monitored, and the wear state of the underwater bearing is determined from the amount of change in the vibration with the passage of operating time.

A preferred embodiment of the above reference example is to measure the vibration of the natural frequency variable member while changing its own natural frequency of the natural frequency variable member attached to the vertical pump, and to measure the natural frequency variable member. The dominant frequency including the natural frequency of the vertical pump is determined from the magnitude of vibration.

Another reference example of the present invention is an inspection method for a vertical shaft pump having a rotary shaft and a submerged bearing that rotatably supports the rotary shaft, and measures vibrations of the vertical pump and includes a predetermined measurement frequency. Monitoring the magnitude of the vibration in a frequency band, and determining the wear state of the submersible bearing from the amount of change in the vibration with the passage of operating time, wherein the measurement frequency is the rotational speed of the vertical shaft N [Min ⁻¹ ], where α is a natural number, is represented by α × (N / 60).

  According to the present invention, it is possible to appropriately estimate or detect the wear state of the underwater bearing while the pump is installed, and to grasp an appropriate replacement time of the underwater bearing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic diagram showing the overall configuration of the vertical shaft pump according to the first embodiment of the present invention.
As shown in FIG. 2, the vertical pump is connected to an impeller casing 1 having a suction bell mouth 1 a and a pump bowl 1 b, a suspension pipe 3 that suspends the impeller casing 1 in a water tank, and an upper end of the suspension pipe 3. A discharge bend tube 4, an impeller 10 accommodated in the impeller casing 1, and a rotating shaft 6 to which the impeller 10 is fixed. The suspension pipe 3 extends downward through an insertion hole 24 formed in the pump installation floor 22 above the water tank, and is fixed to the pump installation floor 22 via a pump base 23 provided at the upper end of the suspension pipe 3. The rotating shaft (vertical shaft) 6 extends in the vertical direction through the discharge curved pipe 4, the suspension pipe 3, and the impeller casing 1. The impeller casing 1 and the suspension pipe 3 constitute a casing 2.

  The suction bell mouth 1a opens downward, and the upper end of the suction bell mouth 1a is fixed to the lower end of the pump bowl 1b. The impeller 10 is fixed to the lower end of the rotating shaft 6, and the impeller 10 and the rotating shaft 6 rotate integrally. A plurality of guide vanes 14 are arranged above the impeller 10 (discharge side). These guide vanes 14 are fixed to the inner peripheral surface of the pump bowl 1b.

  The rotating shaft 6 is rotatably supported by an outer bearing 11, an underwater bearing 12, and an underwater bearing (intermediate bearing) 15. The underwater bearing 12 is accommodated in the pump bowl 1 b and the underwater bearing 15 is accommodated in the suspension pipe 3. The support member 7 that supports the underwater bearing 12 is fixed to the inner surface of the bowl bush 13, and the bowl bush 13 is supported by the impeller casing 1 via a guide vane 14. The support member 17 that supports the underwater bearing 15 is fixed to the inner peripheral surface of the suspension pipe 3. The underwater bearings 12 and 15 are so-called sliding bearings that are in sliding contact with the rotary shaft 6.

  As shown in FIG. 2, the rotating shaft 6 protrudes upward from the discharge curved pipe 4. The upper end of the rotary shaft 6 is connected to a drive shaft 16, and the drive shaft 16 is connected to a drive source 18. When the impeller 10 is rotated by the drive source 18 via the rotary shaft 6, water (handling liquid) in the water tank is sucked from the suction bell mouth 1 a and passes through the pump bowl 1 b, the suspension pipe 3 and the discharge bent pipe 4. To the discharge pipe (not shown). During the vertical pump operation, the impeller casing 1 that houses the impeller 10 and the underwater bearing 12 is located below the water surface.

  A seat 30 is fixed to the outer peripheral surface of the suspension pipe 3 of the casing 2. The seat 30 is made of a hard material and has a flat portion 30a on which the vibrometer 31 is installed. The pump base 23 is formed with a through hole 32 located above the seat 30. The through-hole 32 extends in a substantially vertical direction and has a cross-sectional shape that is large enough to allow the vibrometer 31 to freely move inside the through-hole 32. The through-hole 32 preferably has a size that can be inserted by an operator's hand. The vibration meter 31 is attached to the flat portion 30a of the seat 30 and measures the vibration of the casing 2 (that is, the vertical shaft pump). The vibrometer 31 is connected to the monitoring unit 36 via a cable 35.

  The seat 30 is disposed immediately below the pump base 23. The distance between the seat 30 and the upper surface of the pump base 23 is preferably within 1 m. The vibration meter 31 may be permanently installed on the seat 30 with a magnet or the like, or an operator may manually press the vibration meter 31 against the seat 30 during the inspection to measure vibration.

  When the underwater bearings 12 and 15 are worn, the rotating shaft 6 rotated by the drive source 18 hits the underwater bearings 12 and 15 and vibration is generated. Further, when the wear amount of the underwater bearings 12 and 15 is further increased, the rotating impeller 10 comes into contact with the casing 2 and vibration is generated. These vibrations tend to increase according to the amount of wear of the underwater bearings 12 and 15. Therefore, the wear state of the underwater bearings 12 and 15 can be estimated from the measured value of the vibration of the vertical shaft pump. The above-described monitoring unit 36 determines the wear amount and damage of the underwater bearings 12 and 15 from the measurement values (vibration amplitude, vibration speed, vibration acceleration, etc.) measured by the vibrometer 31 and replaces the underwater bearings 12 and 15. It is configured to estimate or detect the time. Note that the vibration measurement may be performed periodically or the vibration may be constantly monitored. A plurality of seats 30 can also be provided.

  In the present embodiment, since the seat 30 is disposed just below the pump base 23, the position of the seat 30 is usually above the water surface. Therefore, the vibration meter 31 does not need to be waterproofed. The vibrometer 31 may be a size that can be inserted into the through-hole 32 by an operator by hand, and a commercially available vibrometer can be used.

  FIG. 3 is a schematic view showing a part of a vertical shaft pump according to the second embodiment of the present invention. Note that the configuration of the present embodiment that is not particularly described is the same as that of the first embodiment, and thus redundant description thereof is omitted.

  As shown in FIG. 3, a protective tube 40 extending from the through hole 32 to the seat 30 is disposed on the pump base 23. The protective tube 40 is fitted in the through hole 32 without a gap, and the seat 30 is accommodated in the protective tube 40. The lower end (opening end) of the protective tube 40 is fixed to the outer peripheral surface of the casing 2 (suspending tube 3). That is, the lower end of the protective tube 40 is sealed so that liquid does not enter the protective tube 40. The cross section of the protective tube 40 may be circular or rectangular.

  According to such a configuration, since the seat 30 is surrounded by the protective tube 40, even when the liquid level rises, the liquid handled by the vertical pump does not contact the seat 30. Therefore, even when the handling liquid is seawater or sewage, corrosion of the seat 30 is prevented. Even if condensed water or dust accumulates at the bottom of the protective tube 40, the seat 30 is disposed immediately below the pump base 23, so that the condensed water and dust can be easily removed. Furthermore, it is possible to prevent the vibration meter 31 from being accidentally dropped during vibration measurement. Further, since the through-hole 32 is closed by the protective tube 40, the liquid does not overflow the upper surface of the pump base 23 even when the liquid level is raised.

  FIG. 4 is a schematic view showing a part of a vertical shaft pump according to the third embodiment of the present invention. Note that the configuration of the present embodiment that is not particularly described is the same as that of the second embodiment, and therefore redundant description thereof is omitted.

  As shown in FIG. 4, a gap is formed between the outer surface of the protective tube 40 and the inner surface of the through hole 32 so that the protective tube 40 does not suppress vibration of the casing 2. An elastic body 42 such as rubber is attached to the outer surface of the protective tube 40, and the protective tube 40 and the through hole 32 are airtightly connected by the elastic body 42. According to such a configuration, the vibration of the casing 2 is not attenuated by the restraint of the protective tube 40, so that it is possible to measure the vibration with high accuracy. Moreover, since the clearance gap between the protective tube 40 and the through-hole 32 is sealed with the elastic body 42, when a handling liquid is dirty water, the spread of malodor can be prevented.

  As shown in FIG. 5, it is preferable to cover the through hole 32 with a lid 43 while vibration measurement is not being performed. By covering the lid 43, it is possible to prevent the liquid from entering the protective tube 40 when the liquid level rises. Therefore, the elastic body 42 may not be provided.

  FIG. 6 is a schematic view showing a part of a vertical shaft pump according to the fourth embodiment of the present invention. Note that the configuration of the present embodiment that is not particularly described is the same as that of the first embodiment, and thus redundant description thereof is omitted.

  As shown in FIG. 6, the seat 30 of the present embodiment is formed by a rigid body that extends from the casing 2 (the suspension pipe 3) to the pump base 23. More specifically, one end of the seat 30 is fixed to the outer peripheral surface of the casing 2 (suspending pipe 3), and the other end is located in or near the through hole 32 formed in the pump base 23. . At the other end (the upper end in FIG. 6), the above-described flat portion 30a is formed. A lid 43 is covered on the upper end of the through hole 32. At the time of vibration measurement, as shown in FIG. 7, the lid 43 is removed, and the vibrometer 31 is installed on the flat portion 30 a of the seat 30. The flat portion 30a may be positioned above the pump base 23. Further, instead of the lid 43, as shown in FIG. 8, an elastic body 42 such as rubber may be attached below the flat portion 30a, and the gap between the through hole 32 and the seat 30 may be sealed.

  According to this embodiment, it is not necessary to pass the vibrometer 31 through the through hole 32 of the pump base 23, and vibration measurement work can be performed on the pump installation floor 22. Therefore, the measurement work can be easily performed as compared with the first to third embodiments. In particular, the configuration of the present embodiment is effective when it is difficult to attach the vibrometer 31 below the pump base 23 due to the arrangement of the mount of the drive source 18 or the like.

Next, an embodiment of the above-described vertical shaft pump inspection method will be described in detail.
FIG. 9 is a graph showing the relationship between the magnitude of vibration and the frequency of the vertical shaft pump. In FIG. 9, the vertical axis indicates the magnitude of vibration (amplitude, vibration speed, or vibration acceleration), and the horizontal axis indicates the vibration frequency [Hz]. FIG. 10 is a graph showing the relationship between the magnitude of vibration and the elapsed time.

As can be seen from FIG. 9, the magnitude of vibration (amplitude, vibration speed, or vibration acceleration) appears significantly in the natural frequency of the vertical pump. In addition, the magnitude of the vibration appears remarkably even at a predetermined measurement frequency determined according to the rotation speed of the vertical shaft pump. Here, the predetermined measurement frequency is α × (N / 60) [Hz] when the rotational speed of the vertical pump is N [min ⁻¹ ] and α is a natural number (1, 2, 3,...). The frequency represented by. Hereinafter, the natural frequency that is the dominant frequency and the predetermined measurement frequency are collectively referred to as a specific frequency. As shown in FIG. 10, the magnitude of the vibration at the specific frequency gradually increases as the operating time elapses. This is because the underwater bearings 12 and 15 are gradually worn as the operation time elapses. Therefore, the wear amount of the underwater bearings 12 and 15 can be estimated from the change (increase) in the magnitude of vibration with the passage of operating time.

  More specifically, the monitoring unit 36 described above has a magnitude (amplitude, vibration) in the frequency band F1 including the natural frequency (or the frequency band F2 including the measurement frequency determined from the rotation speed of the pump). The speed or vibration acceleration) is monitored, and it can be determined that the replacement timing of the underwater bearings 12 and 15 has been reached when the amount of change in vibration with time has reached a predetermined value.

  In general, since the operation state of a vertical pump varies depending on the liquid level position in the water tank, it is difficult to always measure the vibration of the vertical pump under the same conditions. According to the present embodiment, by monitoring the frequency (specific frequency) at which the magnitude of vibration appears noticeably or the magnitude of vibration in a frequency band including the specific frequency, the submersible bearing is almost independent of the water level in the aquarium. It is possible to grasp the change (increase) in the magnitude of vibration generated by the wear of 12,15. Therefore, the amount of wear of the underwater bearings 12 and 15 can be estimated appropriately.

  Further, the natural frequency of the vertical pump slightly differs depending on the installation state of the vertical pump (for example, the method of fixing the vertical pump to the pump installation floor). It is impossible to reproduce the installation state of the vertical shaft in the pump manufacturing factory, and there is also a difference between the natural frequency obtained by calculation and the actual natural frequency. Therefore, it is preferable that the natural frequency is obtained in a state where the vertical shaft pump is actually fixed to the pump installation floor, and the wear amount of the submerged bearing is determined based on the magnitude of vibration in the frequency band including the natural frequency.

  Hereinafter, an example of a method for measuring the natural frequency of a vertical shaft pump installed in the field will be described. In this example, the natural frequency is measured by applying an external force to the vertical pump while the vertical pump is fixed to the pump installation floor 22 at the upper part of the water tank. Specifically, as shown in FIG. 11, the lid 51 is removed from the insertion port 50 formed in the pump base 23, and a striking tool 52 such as a hammer is inserted into the insertion port 50, and the casing 2 is used with the striking tool 52. Blow. At this time, the vibration of the vertical pump is measured by the above-described vibrometer 31, and the natural frequency is obtained. Thus, by obtaining the natural frequency of the vertical pump while the vertical pump is fixed to the pump installation floor 22, the wear amount of the underwater bearings 12 and 15 can be estimated with higher accuracy.

  Next, another method for measuring the natural frequency of the vertical shaft pump will be described. As shown in FIG. 12A, a rod-like natural frequency variable member 53 is attached to the top of the pump base 23. The natural frequency variable member 53 has a screw structure, and its own natural frequency can be changed by changing its length, as shown in FIG. The vibration of the natural frequency variable member 53 is measured while changing the natural frequency of the natural frequency variable member 53 (that is, changing the length of the natural frequency variable member 53).

  Specifically, when the natural frequency variable member 53 vibrates greatly during the operation or impact of the vertical shaft pump, that is, the dominant frequency at the time of resonance is captured, the natural frequency of the vertical pump is determined from this dominant frequency. Thus, the natural frequency of the vertical pump can be obtained from the magnitude of the vibration of the natural frequency variable member 53. Also in this case, the natural frequency of the vertical pump can be obtained in a state where the vertical pump is fixed to the pump installation floor 22, so that the change in the magnitude of the vibration of the vertical pump as the operation time elapses can be properly monitored. it can.

  FIGS. 13A and 13B are schematic views showing other examples of the natural frequency variable member. In this example, the natural frequency variable member 54 can change its own natural frequency by changing its mass. That is, the natural frequency variable member 54 has a plurality of detachable weights 54a, and the natural frequency of the natural frequency variable member 54 as a whole is variable depending on the number of attached weights 54a. It is also possible to change the mass of the natural frequency variable member 54 as a whole by providing a hollow portion inside the natural frequency variable member 54 and putting a substance having a certain mass such as liquid into the hollow portion. .

  In addition, the attachment location of the natural frequency variable member is not limited to the pump base 23. For example, a natural frequency variable member may be attached to the casing 2. Further, as shown in FIG. 14, the natural frequency variable member 53 (or 54) may be fixed to the seat 30. According to such a configuration, by adjusting the natural frequency of the natural frequency variable member to the natural frequency of the vertical pump or the above measurement frequency, the vibration of the vertical pump can be amplified and measured, More accurate vibration measurement is possible.

  Moreover, although the above-mentioned embodiment demonstrated the example which estimates the abrasion loss of the underwater bearings 12 and 15, this invention is not limited to this example. For example, an underwater bearing provided below the impeller 10 (for example, an underwater bearing that supports the tip of the rotating shaft) may be monitored. Further, the vibration measurement location may be the outer bearing 11 or the pump base 23.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.

It is a schematic diagram which shows the conventional vertical shaft pump. It is a mimetic diagram showing the whole vertical shaft pump composition which is a 1st embodiment of the present invention. It is a schematic diagram which shows a part of vertical pump which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows a part of vertical shaft pump which concerns on the 3rd Embodiment of this invention. It is a schematic diagram which shows a part of vertical pump which concerns on 3rd Embodiment mentioned above. It is a schematic diagram which shows a part of vertical shaft pump which concerns on the 4th Embodiment of this invention. It is a schematic diagram which shows the mode at the time of vibration measurement. It is a schematic diagram which shows the other structural example of the vertical shaft pump which concerns on 4th Embodiment mentioned above. It is a graph which shows the relationship between the magnitude | size of the vibration of a vertical shaft pump, and a frequency. It is a graph which shows the relationship between the magnitude | size of vibration, and elapsed time. It is a schematic diagram for demonstrating an example of the measuring method of the natural frequency of a vertical shaft pump. FIG. 12A and FIG. 12B are schematic views showing an example of the natural frequency variable member. FIGS. 13A and 13B are schematic views showing other examples of the natural frequency variable member. It is a schematic diagram which shows an example of the installation location of a natural frequency variable member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Impeller casing 1a Suction bell mouth 1b Pump bowl 2 Casing 3 Suspension pipe 4 Discharge curved pipe 6 Rotating shaft 7, 17 Support member 10 Impeller 11 Outer bearing 12, 15 Underwater bearing 13 Bowl bush 14 Guide vane 16 Drive shaft 18 Drive Source 19 Hand hole 22 Pump installation floor 23 Pump base 24 Pump insertion hole 30 Seat 30a Flat part 31 Vibrometer 32 Through hole 35 Cable 36 Monitoring part 40 Protective tube 42 Elastic body 43 Lid 44 Extension tube 50 Insertion port 52 Impacting tool 53, 54 Natural frequency variable member

Claims (4)

A rotation axis;
An impeller fixed to the rotating shaft;
An underwater bearing that rotatably supports the rotating shaft;
A casing for housing the impeller and the underwater bearing;
A vertical shaft pump comprising a pump base connecting the casing to a pump installation floor,
A seat is attached to the outer surface of the casing,
The seat is located below and near the pump base;
The seat has a substantially flat portion on which a vibrometer that measures the vibration of the vertical shaft pump is installed,
The pump base has a through hole located above the seat,
The vertical shaft pump includes a protective tube for guiding the vibrometer from the through hole to the seat,
The vertical shaft pump, wherein the seat is disposed inside the protective tube.   The vertical shaft pump according to claim 1, wherein the protective tube and the through hole are connected via an elastic body.   The vertical shaft pump according to claim 1, wherein the seat is a rigid body extending from an outer surface of the casing to the through hole. It further comprises a natural frequency variable member configured to variably have its own natural frequency,
The vertical shaft pump according to claim 1, wherein the natural frequency variable member is attached to any of the casing, the pump base, and the seat.

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