JP2002213384A - Vertical shaft pump for precedent standby operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical shaft pump for a precedent standby operation that is not damaged by abrasion or heat generation of a bearing even in the precedent standby operation. SOLUTION: An underwater radial bearing 43 and a magnetic bearing 50 are disposed as bearings inside pump casings 10, 13, 15, and 20 of a shaft 11 for rotating an impeller 21 disposed in the pump casings 10, 13, 15, and 20. The magnetic bearing 50 is used as a main bearing during a dry operation of the pump, and the underwater radial bearing 43 is used as the main bearing during a pumping operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical pump capable of waiting in a standby mode.

[0002]

2. Description of the Related Art In urban areas, where buildings are dense and road pavements are widespread, rainwater does not permeate the ground during heavy rains and flows into a drainage pump station at a stroke. On the other hand, since the drain pump of the drain pump station driven by the engine takes time from the start to the completion of the start, if the drain pump is started after the suction water level of the drain pump station rises, drainage cannot be completed in time. For this reason, the drainage pumping station takes measures to start the pump empty in the atmosphere at the same time as the precipitation, and to perform a preparatory standby operation waiting for the water to flow thereafter. Therefore, after the pump is started, dry operation is performed in the atmosphere from the time when water flows into the water absorption tank of the drainage pumping station until the actual drainage starts.

FIG. 5 is a schematic sectional view showing a conventional preparatory standby pump of this type. As shown in the figure, the preceding standby operation pump has an impeller casing 82 containing a discharge casing 81 and an impeller 87 and a suction bell mouth 84 attached to a lower portion of a hanging casing 80, and an upper portion of the hanging casing 80. The pump 86 has a curved discharge casing 85 attached thereto, and a shaft 86 installed inside the pump casing projects from an upper portion of the discharge casing 85 and is connected to driving means (not shown).

A guide vane 88 is fixed in the discharge casing 81, a casing 89 is mounted in the center of the guide vane 88, and a bearing (lower bearing) 91 of a shaft 86 is mounted in the casing 89. . This bearing is a radial bearing with water lubrication.

On the other hand, a portion of the shaft 86 projecting from the discharge casing 85 to the outside is provided with a shaft sealing portion 95 for preventing the internal pumping water from leaking out. A bearing (upper bearing) 97 is provided. This bearing is an oil-lubricated radial thrust bearing.

However, preliminary standby operation (dry operation)
At times, there is no water for lubricating and cooling the bearing (lower bearing) 91 by water lubrication, so that damage due to wear and heat generation may occur. However, since the upper bearing 97 is installed in the oil outside the pump casing, there is no problem of damage.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a standby standby operation which does not cause damage due to wear or heat generation of a bearing even during a standby standby operation. An object of the present invention is to provide a corresponding vertical pump.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a preparatory stand-by system in which a bearing for a shaft for rotating and driving an impeller installed in a pump casing is provided above the pump casing and inside the pump casing. In the operation-ready vertical shaft pump, the bearing inside the pump casing is:
It is a radial bearing composed of a magnetic bearing.

[0009] The present invention also provides a vertical shaft pump that supports a shaft for rotationally driving an impeller provided in a pump casing and is provided in an upper portion of the pump casing and inside the pump casing. Is a submerged radial bearing and a magnetic bearing.

The present invention also provides a measuring device for detecting the presence or absence of water inside the pump casing of the vertical shaft pump corresponding to the preceding standby operation, and the magnetic device when the measuring device detects the presence of water inside the pump casing. Control means for stopping the operation of the bearing is provided.

Further, the present invention is characterized in that a bearing clearance of the magnetic bearing is made larger than a bearing clearance of an underwater radial bearing.

Further, the present invention is characterized in that a touchdown bearing having a bearing clearance smaller than a bearing clearance of the magnetic bearing is provided.

Further, the present invention provides a touch-down bearing having a bearing clearance smaller than a bearing clearance of the magnetic bearing and a bearing clearance larger than a service limit bearing clearance when the underwater radial bearing is worn. It is characterized by.

Further, the present invention is characterized in that a control means for inputting an output of a magnetic bearing control displacement meter for detecting displacement with respect to the shaft and detecting a state of a pump for use in controlling the magnetic bearing is provided. And

Further, the present invention is characterized in that an uncontrolled repulsive permanent magnet type magnetic bearing is used as the magnetic bearing.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a main part of a vertical shaft pump corresponding to a preceding standby operation using an embodiment of the present invention. As shown in the figure, this pump has an impeller casing 20 containing a discharge casing 13 and an impeller 21 and a suction bell mouth 25 below a suspension pipe 10, and is bent over the suspension pipe 10. Discharge casing 1
5, the upper part of the shaft 11, which is set up inside the pump casing, protrudes from the curved upper side surface of the discharge casing 15 and is supported by the upper thrust radial bearing 27. Through a driving means such as a diesel engine or a gas turbine (not shown). A shaft sealing portion 35 is provided at a portion where the shaft 11 protrudes from the upper portion of the discharge casing 15 to the outside so that pumped water does not leak outside. Reference numeral 37 denotes an intermediate bearing (underwater bearing by water lubrication) which supports the shaft 11 at an intermediate portion. The intermediate bearing 37 is provided at one or more positions as needed. Since the thrust radial bearing 27 is installed outside the discharge casing 15, oil lubrication can be performed.

Here, a casing 40 formed in a shape for smoothing the flow of water is installed above the impeller 21 so as to cover the shaft 11.
A submerged bearing 43 that supports the shaft 11 in the radial direction is mounted therein. The casing 40 itself is fixed to the center of the discharge casing 13 by a guide vane 45. And in the present invention, the casing 40
, A magnetic bearing 50 is provided.

FIG. 2 is an enlarged sectional view of a main part showing the underwater radial bearing 43 and the magnetic bearing 50 in an enlarged manner.
As shown in the figure, the underwater radial bearing 43 has a cylindrical shape, and is configured to cover the shaft 11 so as to rotatably support the shaft 11. This underwater radial bearing 4
3 is P in this embodiment with the carbon fiber incorporated.
It is formed by molding an EEK (polyether ether ketone) material into a cylindrical shape, but may be formed of another material (for example, another synthetic resin material or ceramics) or structure.

On the other hand, the magnetic bearing 50 is a radial bearing comprising a rotor core 55 fixed to the shaft 11 and a stator core 57 fixed to the casing 51 covering the magnetic bearing 50. The magnetic bearing 50 has a can structure, and a rotor can 56 and a stator can 58 are attached to opposing surfaces of the rotor core 55 and the stator core 57, respectively, so that the inside of the rotor and the stator is sealed. A magnetic bearing cable 59 is drawn out of the suspension core 10 from the stator core 57. Under the stator core 57, an underwater displacement meter (magnetic bearing control displacement meter) 61 for measuring a gap size with the shaft 11 is installed in the XY axis direction on a plane perpendicular to the axis of the shaft 11. The output of the underwater displacement meter 61 is input to the control means 100 via the cable 63 as shown in FIG. 1, and is used for the bearing control of the shaft 11 by the magnetic bearing 50. The casing 51 is a stay 5
3 is fixed to the suspension tube 10. Further, the gap between the upper and lower portions of the casing 51 penetrating the shaft 11 is reduced to prevent foreign matter from entering the casing 51.

In order to protect the magnetic bearing 50, the size of the bearing gap (gap between the rotor can 56 and the stator can 58) of the magnetic bearing 50 is made larger than that of the underwater radial bearing 43 (gap between the shaft 11 and the underwater radial bearing 43). Is also bigger.

On the other hand, the control means 100 shown in FIG. 1 drives and controls the magnetic bearing 50, and measures the water level and discharge pressure inside the pump casing by measuring means (not shown) such as a water level sensor and a pressure sensor. When the presence of water is detected, control is performed to stop driving the magnetic bearing 50.

If the shaft 11 is rotationally driven by driving the driving means (not shown) of the vertical shaft pump for the preceding standby operation configured as described above, the impeller 21 starts to rotate. In the case of the preliminary standby operation, the dry operation is performed in the atmosphere from the start of the pump to the time when water flows into the water absorption tank of the drainage pumping station and the actual drainage is started. Drives and controls the magnetic bearing 50. That is, in this embodiment, the magnetic bearing 50 is used as the lower bearing (the bearing in the pump casing).
And the underwater radial bearing 43 are installed. In the dry operation, the magnetic bearing 50 is used as a main radial bearing, and the underwater radial bearing 43 is used as an auxiliary radial bearing. Since the magnetic bearing 50 is a non-contact bearing, it does not generate heat or wear due to friction even in dry operation. On the other hand, the underwater radial bearing 43
Since the magnetic bearing 50 securely supports the shaft 11 even when there is no water for lubricating and cooling it during the dry operation, wear and heat generation do not occur, and the damage can be reliably prevented.

The thrust / radial bearing 27 supports a thrust load when the pump is driven. Therefore, the magnetic bearing 50 supports only the pump radial fluid force,
Since there is no need to support the weight of the rotor (including the shaft 11 and the impeller 21) that causes a large thrust force, the unit of the magnetic bearing 50 can be reduced. The magnetic bearing 50 has a smaller bearing supporting force density than other bearings, and when used in a pump, has a larger size than a conventional bearing, and the size of the pump itself may be enlarged. In addition, there is no problem because the magnetic bearing 50 can be made compact.

Then, the water in the water absorption tank is sucked by the impeller 21 from the suction bell mouth 25, the water flows into the pump casing, is pumped toward the discharge casing 15 shown in FIG. 1, and the actual drainage is started. When the measurement means (not shown) (for example, a water level sensor or a pressure sensor) detects this, the drive of the magnetic bearing 50 is stopped by the control means 100, and thereafter, the underwater radial bearing 43 is used as a main radial bearing. In this case, since there is water in the pump casing, the water causes
3 can be lubricated and cooled, and there is no problem of damage due to wear or heat generation. Even if the drive of the magnetic bearing 50 is stopped, the magnetic bearing 5
Since the zero bearing gap is larger than the underwater radial bearing 43, the magnetic bearing 50 is not damaged.

As described above, the dry operation is a time when the need for the magnetic bearing 50 is high. However, in the dry operation, since there is no water, the bearing load is small. On the other hand, in other states, water is present in the pump casing, the fluid force increases, and the bearing load also increases.
3 are available. Therefore, the magnetic bearing 50 can be further reduced in size by using the magnetic bearing 50 as the main bearing only during the dry operation and the underwater radial bearing 43 as the main bearing in other states.

The magnetic bearing 50 is classified into a control type suction type and a non-control type repulsion type. When the radial bearing is a repulsion type, the shaft 11 tends to escape in the axial direction.
In this pump, since the axial movement of the shaft 11 can be restrained by the upper thrust radial bearing 27, the problem is eliminated and an uncontrolled repulsion type can be used. Further, in the non-control type, since control by an electromagnet is not required, this can be replaced with a permanent magnet (non-control type repulsive permanent magnet type magnetic bearing), and the magnetic bearing cable 59 which is difficult to handle can be eliminated.

On the other hand, the control means 100 performs the following control in addition to the drive and control of the magnetic bearing 50. That is, in the control type magnetic bearing 50, the amount of eccentricity of the shaft 11 is measured by the underwater displacement meter 61 in order to control the shaft 11 to an appropriate state, and the state of the pump is also diagnosed based on the amount of eccentricity. That is, specifically, the underwater displacement meter (magnetic bearing control displacement meter) 61 is constantly monitored, and the state of the pump,
For example, the amount of eccentricity of the shaft 11 when water is present in the pump (other than the dry operation) is measured, and the degree of wear of the underwater radial bearing 43 is measured to determine whether pump operation is possible and whether maintenance is necessary. If the amount of eccentricity suddenly increases, it is determined that there is a possibility of failure of any part, and an alarm is issued or the operation of the pump is stopped.

FIG. 3 is an enlarged sectional view showing a main part of an underwater radial bearing 43 and a magnetic bearing 50 of a vertical shaft pump corresponding to a preceding standby operation according to another embodiment of the present invention.
In this embodiment, the same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. That is, this embodiment is different from the above-described embodiment in that the magnetic bearing 5
The only difference is that the touchdown bearing 60 is attached to the upper part of the zero. The touch-down bearing 60 is made of a ball bearing made of a corrosion-resistant material such as ceramics or stainless steel. The bearing gap between the touch-down bearing 60 and the shaft 11 is defined by the relationship between the bearing gap of the magnetic bearing 50 and the bearing gap of the underwater radial bearing 43. The bearing clearance of the magnetic bearing 50> the bearing clearance of the touch-down bearing 60> the useable bearing clearance of the underwater radial bearing 43.

The reason why the bearing clearance of the touch-down bearing 60 is made smaller than that of the magnetic bearing 50 is to protect the magnetic bearing 50. The usage limit bearing clearance of the underwater radial bearing 43 refers to a usage limit bearing clearance when the bearing clearance increases due to wear of the underwater radial bearing 43. That is, the underwater radial bearing 43 is provided to protect the magnetic bearing 50, but the touchdown bearing 60 is provided just in case. In other words, even though the axial runout in the underwater radial bearing 43 is small, the axial runout in the magnetic bearing 50 apart from the underwater radial bearing 43 may be large. We are trying to protect it.
In this embodiment, a ball bearing is used as the touch-down bearing 60. However, a cylindrical ceramic or a cylindrical PEEK
It may be constituted by a bearing made of a resin material such as.

FIG. 4 shows a submerged radial bearing 43 of a vertical shaft pump corresponding to a preceding standby operation according to still another embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part showing a part of a magnetic bearing 50 in an enlarged manner. In this embodiment, the same parts as those of the embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. That is, this embodiment is different from the above embodiments in that the magnetic bearing 50 is installed at a position directly above the underwater radial bearing 43 in the casing 40. With this configuration, the pump can be made more compact.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims and the technical idea described in the specification and the drawings. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and effects of the present invention are exhibited.

For example, in the above embodiment, the magnetic bearing 5
Although a cand-type magnetic bearing was used as 0, when a non-cand-type magnetic bearing is used, it is preferable to use a resin-wound, water-resistant, insulated wire as a coil for the magnetic bearing.

In each of the above embodiments, the magnetic bearing and the underwater radial bearing are used as the bearings installed inside the pump casing. However, the underwater radial bearing may be omitted and only the magnetic bearing may be used.

[0034]

As described in detail above, the present invention has the following excellent effects. Since a radial bearing made of a magnetic bearing is used as a bearing inside the pump casing, there is no damage caused by wear or heat generation of the bearing even during the preliminary standby operation.

Since the underwater radial bearing and the magnetic bearing are used as the bearings inside the pump casing, they are suitable for both the dry operation and the actual pumping operation. In particular, a small magnetic bearing can be used. The overall size can be reduced.

Since the bearing clearance of the magnetic bearing is made larger than that of the underwater radial bearing, protection of the magnetic bearing can be achieved. Further, if a touchdown bearing having a bearing clearance smaller than the bearing clearance of the magnetic bearing is provided, the magnetic bearing can be further protected.

The state of the pump can be detected using a displacement meter for detecting the displacement of the shaft for use in controlling the magnetic bearing.

When an uncontrolled repulsive permanent magnet type magnetic bearing is used as the magnetic bearing, control by an electromagnet is not required, and a magnetic bearing cable which is difficult to handle can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a vertical shaft pump compatible with a preceding standby operation using one embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of an underwater radial bearing 43 and a magnetic bearing 50 in an enlarged manner.

FIG. 3 is an enlarged cross-sectional view showing a main part of a submerged radial bearing 43 and a magnetic bearing 50 of a vertical shaft pump compatible with a preliminary standby operation according to another embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a main part, showing a part of a submerged radial bearing 43 and a magnetic bearing 50 of a vertical shaft pump compatible with a preceding standby operation according to still another embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a conventional preparatory standby operation pump.

[Explanation of symbols]

 Reference Signs List 10 Suspension pipe (pump casing) 11 Shaft 13 Discharge casing (pump casing) 15 Discharge casing (pump casing) 20 Impeller casing (pump casing) 21 Impeller 25 Suction bellmouth 27 Thrust / radial bearing 35 Shaft sealing part 40 Casing 43 Underwater radial bearing 45 Guide vane 50 Magnetic bearing 51 Casing 53 Stay 55 Rotor core 56 Rotor can 57 Stator core 58 Stator can 59 Magnetic bearing cable 60 Touchdown bearing 61 Underwater displacement meter (magnetic bearing control displacement meter) 100 Control means

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshihiko Ando 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside Ebara Research Institute, Ltd. (72) Inventor Satoshi Mori 4-2-2 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture No. 1 F-term in EBARA Research Institute (Reference) 3H020 AA01 AA07 BA11 BA21 CA00 CA07 DA00 3H022 AA01 BA06 CA11 CA12 CA16 CA17 CA20 DA09 3H045 AA06 AA09 AA12 AA23 AA31 AA39 BA31 BA41 CA00 CA14 DA00

Claims (5)

[Claims] 1. A vertical shaft pump which supports a shaft for rotating an impeller installed in a pump casing and which is provided at an upper portion of the pump casing and inside the pump casing, wherein the bearing inside the pump casing is magnetic. A vertical shaft pump compatible with advance standby operation, which is a radial bearing composed of a bearing. 2. A vertical shaft pump corresponding to a preparatory standby operation, wherein a bearing of a shaft for rotationally driving an impeller installed in a pump casing is provided in an upper portion of the pump casing and in the pump casing. A vertical shaft pump compatible with advance standby operation, characterized by a radial bearing and a magnetic bearing. 3. The vertical stand-by pump corresponding to the preceding standby operation, wherein: a measuring means for detecting the presence or absence of water inside the pump casing; and the magnetic bearing is provided when the measuring means detects the presence of water inside the pump casing. 3. The vertical pump according to claim 2, further comprising control means for stopping the operation. 4. The vertical shaft pump according to claim 1, wherein a touchdown bearing having a bearing clearance smaller than a bearing clearance of the magnetic bearing is provided. 5. A control means for detecting the state of a pump by inputting an output of a magnetic bearing control displacement meter for detecting displacement with respect to the shaft for use in controlling the magnetic bearing. Item 3. The vertical shaft pump corresponding to the preceding standby operation according to item 1 or 2.