WO2017212533A1

WO2017212533A1 - Vertical shaft pump

Info

Publication number: WO2017212533A1
Application number: PCT/JP2016/066820
Authority: WO
Inventors: 裕輔渡邊; 正治石井; 真小宮; 内田　義弘
Original assignee: 株式会社荏原製作所
Priority date: 2016-06-07
Filing date: 2016-06-07
Publication date: 2017-12-14
Also published as: JP6749393B2; JPWO2017212533A1

Abstract

Provided is a vertical shaft pump in which the centrifugal whirling of a rotational shaft, which occurs with increased frequency and intensity as rotational shafts are lengthened, has been appropriately reduced for the entire rotational shaft.　Specifically provided is a vertical shaft pump for standby operation, said pump comprising a rotational shaft, an impeller attached to the rotational shaft, and an air pipe upstream from the impeller. The vertical shaft pump further comprises a plurality of slide bearing devices that support the rotational shaft, wherein some of the plurality of slide bearing devices are first slide bearing devices that are used when the sliding surface is in an air environment during in-air operation, and the remainder of the plurality of slide bearing devices are second slide bearing devices that are normally used when the sliding surface is in a liquid environment.

Description

Vertical shaft pump

The present invention relates to a vertical shaft pump. More specifically, operation management is performed under dry conditions such as a vertical shaft pump that performs management operation by rotating the rotary shaft of the pump while water is not filled into the pump casing of the vertical shaft pump or a preceding standby operation pump. The present invention relates to a vertical shaft pump.

In recent years, due to the progress of urbanization, the heat island phenomenon has occurred due to the decrease in green space, the concrete on the road surface, and the expansion of asphalt. A large amount of local rainfall is introduced into the waterway without being absorbed into the ground on concrete and asphalt road surfaces. As a result, a large amount of rainwater flows into the drainage station in a short time.

In order to prepare for the rapid drainage of a large amount of rainwater caused by such frequent torrential rains, drainage pumps installed in the drainage pump station should have rainwater before reaching the drainage pump station in order to prevent inundation damage due to delays in starting. Pre-standby operation to be started is performed.

FIG. 1 is a partial schematic diagram of a vertical shaft pump that performs a preliminary standby operation. Even if the water level of the water tank 100 is equal to or lower than the minimum operating water level LWL, the water tank 100 of the drainage pump station is provided with an impeller 22 at the tip of the rotary shaft 10 arranged vertically and the air is sucked into the impeller 22 together with water. A vertical shaft pump 3 capable of continuing the operation (preceding standby operation) is disposed. This vertical shaft pump 3 is provided with a through hole 5 in the side surface of the suction bell 27 on the inlet side of the impeller 22, and an air pipe 6 having an opening 6 a in contact with outside air is attached to the through hole 5. ing. Thereby, in this vertical shaft pump 3, the supply amount of the air supplied into the vertical shaft pump 3 through the through hole 5 is changed according to the water level, and the drainage amount of the vertical pump 3 is controlled below the minimum operating water level LWL.

FIG. 2 is a diagram for explaining the operating state of the preceding standby operation. As described above, in order to prevent inundation damage due to a delay in starting, for example, for a rainwater drainage in a large city, a vertical shaft pump is started in advance based on rainfall information or the like regardless of the suction water level (A: air operation). When rainwater reaches the drainage station, as the water level rises from a low water level, the water level reaches the impeller position, and the vertical shaft pump is an operation that stirs water with the impeller from an empty operation (air operation) (B: air water) Agitation operation), and a full amount operation (D: steady operation) in which 100% water is discharged through an operation of gradually increasing the amount of water (C: air-water mixing operation) while sucking in air supplied through the through-holes. Migrate to When the water level drops from the high water level, the operation shifts from the full operation to the operation of gradually reducing the water amount while sucking in the air supplied through the through holes together with the water (C: air-water mixing operation). When the water level reaches near LLWL, the operation shifts to an operation (E: air lock operation) in which water is not sucked and drained. These five characteristic operations are collectively referred to as advance standby operation. The pump start is started from the water level LLLWL lower than the lower end of the casing.

FIG. 3 is a cross-sectional view showing an entire conventional vertical shaft pump 3 that performs the preliminary standby operation shown in FIG. The through hole 5 and the air pipe 6 shown in FIG. 2 are not shown. As shown in FIG. 3, the vertical shaft pump 3 includes a discharge elbow 30 installed and fixed on the pump installation floor, a casing 29 connected to the lower end of the discharge elbow 30, and a lower end of the casing 29 and an impeller 22. And a suction bell 27 that is connected to the lower end of the discharge bowl 28 and sucks water.

A single rotating shaft 10 formed by connecting two upper and lower shafts to each other by a shaft coupling 26 is provided at substantially the center in the radial direction of the casing 29, the discharge bowl 28, and the suction bell 27 of the vertical shaft pump 3. Has been placed. The rotary shaft 10 is supported by an upper slide bearing device 32 fixed to the casing 29 via a support member, and a lower slide bearing device 33 fixed to the discharge bowl 28 via a support member. An impeller 22 for sucking water into the pump is connected to one end side (suction bell 27 side) of the rotating shaft 10. The other end of the rotating shaft 10 extends to the outside of the vertical shaft pump 3 through a hole provided in the discharge elbow 30 and is connected to a driving machine such as an engine or a motor that rotates the impeller 22.

A shaft seal 34 such as a floating seal, a gland packing, or a mechanical seal is provided between the rotary shaft 10 and a hole provided in the discharge elbow 30, and the water handled by the vertical pump 3 by the shaft seal 34 is supplied to the vertical pump. 3 is prevented from flowing out.

The drive will be installed on land so that maintenance and inspection can be performed easily. The rotation of the driving machine is transmitted to the rotary shaft 10 and the impeller 22 can be rotated. The water is sucked from the suction bell 27 by the rotation of the impeller 22, passes through the discharge bowl 28 and the casing 29, and is discharged from the discharge elbow 30.

FIG. 4 is an enlarged view of the sliding bearing device used in the sliding bearing

devices

32 and 33 shown in FIG. FIG. 5 is a perspective view of a plain bearing installed in the plain bearing device shown in FIG. As shown in FIG. 4, the rotating shaft 10 has a sleeve 11 made of stainless steel, ceramics, sintered metal, or surface-modified metal on the outer periphery thereof. A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided on the outer peripheral side of the sleeve 11. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The slide bearing 1 is fixed to a support member 13 connected to a pump casing 29 (see FIG. 3) or the like via a collar portion 12a by a bearing case 12 made of metal or resin. As shown in FIG. 5, the plain bearing 1 has a hollow cylindrical shape, the inner peripheral surface 1 a faces the outer peripheral surface of the sleeve 11, and the outer peripheral surface 1 b is fitted in the bearing case 12.

The vertical shaft pump 3 shown in FIG. 3 is operated in the atmosphere when the pump is started. At this time, the sliding bearing

devices

32 and 33 are operated under dry conditions without liquid lubrication. Here, the dry condition refers to a condition in which the atmosphere of the sliding portion of the slide bearing 1 and the sleeve 11 of the slide bearing

devices

32 and 33 during the pump operation is in the air without liquid lubrication. Driving under conditions. Further, the plain bearing

devices

32 and 33 shown in FIG. 4 are operated even under drainage conditions. Here, the drainage condition refers to a condition in which the atmosphere of the slide bearing

devices

32 and 33 during the pump operation is in water mixed with foreign matter (slurry) such as earth and sand, and the drainage operation is to operate under that condition, For example, it refers to air-water mixing operation, full-volume operation, air lock operation and the like. Under these conditions, the plain bearing

devices

32 and 33 are used. In the vertical shaft pump 3 in FIG. 3, the slide bearing

devices

32 and 33 are arranged at two locations on the rotary shaft 10. However, if the length of the rotary shaft 10 increases, more bearings are arranged accordingly. Is done.

By the way, in recent years, pumping stations have been placed deeper underground, and advance standby pumps are also becoming longer shafts accordingly. The longer the rotating shaft is, the more the portion of the rotating shaft is swung around. In order to suppress the swinging of the shaft, it has become necessary to arrange more slide bearings at appropriate positions along the rotating shaft.

However, this may cause new technical problems. FIG. 6 is a schematic cross-sectional view showing a state of the rotary shaft 10, the sleeve 11, and the slide bearing 1 in a pump in which the slide bearing

devices

32 and 33 are arranged in a portion where the shaft swings heavily. In the dry operation, when the slide bearing 1 of the slide bearing

devices

32 and 33 and the sleeve 11 attached to the rotary shaft 10 slide, the frictional force at the contact portion (portion indicated by hatching) increases and wears. The frictional heat generated at the same time is increased. Therefore, there is a concern about damage to the slide bearing 1 and the sleeve 11.

On the other hand, the rotary shaft and the slide bearing have been conventionally surrounded by a protective tube so that the pump can be operated with the sliding surface of the slide bearing existing in water even during dry operation. Thus, it has been proposed to allow fresh water to flow into the protective tube, or to replace all the sliding bearing devices with water that accumulates in the sliding bearing devices so that the sliding surface exists in the water. . However, when a protective tube is used, a facility for supplying water to the protective tube is required, and maintenance of the slide bearing device is difficult. In addition, when water is stored in the slide bearing device and replaced with one that has a sliding surface in the water, the structure of the slide bearing device becomes complicated, which increases the cost and makes maintenance difficult. In addition, there is a problem that there is a problem, and since the size of the slide bearing device is increased, there is a problem that the resistance of the water flow is caused and the pump performance is lowered.

In the first place, it is only necessary to appropriately reduce the rotation of the rotating shaft as a whole, but until now, there have been many local measures such as measures for bearings with a large bearing load. It was.

Therefore, the inventors have a sliding bearing device that has a mechanism that, when the rotating shaft slides in dry operation, generates a couple of frictional forces that are opposite to each other to cancel the frictional force and suppress the swinging of the rotating shaft. (See Patent Document 1).

In this plain bearing device, the canceling force depends on the magnitude of the deflection width (radial deflection width) perpendicular to the axial direction of the rotating shaft. That is, when this slide bearing device is arranged in a place (antinode) where the swing of the rotating shaft is large, the effect of suppressing the swing is great, but this slide bearing device is installed in a place (node) where the swing of the rotating shaft is small. If this is arranged, this effect is difficult to obtain.

However, it is difficult to know in advance exactly which part of the rotary shaft of the vertical pump that extends vertically is the maximum (antinode) or minimum (node), and the axial direction of the rotary shaft There is a possibility that the invented slide bearing device may be mistakenly arranged at a position of a node having a small vertical swing width. When this sliding bearing device is arranged at the position of the node, it is difficult to suppress the swing of the rotating shaft. Also, once the plain bearing is attached to the vertical shaft pump, its position cannot be modified. Moreover, since the slide bearing device of the present invention is large in size, it is necessary to arrange the plain bearing device so as not to hinder the pump performance and the fluid flow, and the arrangement position is limited. Therefore, depending on the position where it can be arranged, there is a case where a sufficient reverse couple cannot be exhibited.

International Publication No. 2015/012350 Japanese Patent Laying-Open No. 2015-222117 JP-A-6-94035 JP 2000-130390 A JP 2001-289191 A

The present invention has been made in view of the above problems, and is more likely to occur when the rotating shaft becomes longer when operating in a state where the water surface does not reach the pump casing of the vertical shaft pump. An object of the present invention is to provide a vertical shaft pump that appropriately reduces the swaying of a rotating shaft as a whole as a whole.

According to an aspect of the present invention, there is provided a vertical shaft pump including a rotary shaft, a pump casing that houses at least a part of the rotary shaft, and an impeller attached to the rotary shaft. The vertical shaft pump includes a plurality of sliding bearing devices that support the rotating shaft, and a part of the plurality of sliding bearing devices is used in a state where a sliding surface is in an air atmosphere during an air operation. It is a slide bearing device, and the rest of the plurality of slide bearing devices is a second slide bearing device that is used in a state where the sliding surface is always in a liquid atmosphere.

In one embodiment of the present invention, the second plain bearing device includes a perfect circle bearing or a multi-arc bearing.

In one embodiment of the present invention, the vertical shaft pump has a discharge bowl that houses the impeller, and the second sliding bearing device is provided at a height higher than the discharge bowl.

In one aspect of the present invention, the second slide bearing device includes a slide bearing that supports the rotating shaft, and a liquid receiving tank that holds the liquid so that a sliding portion of the slide bearing contacts the liquid. Have.

In one embodiment of the present invention, the second sliding bearing device is disposed above the sliding bearing and has a plate member for holding the liquid together with the liquid receiving tank.

In one embodiment of the present invention, the plate member has a cylindrical shape and is configured such that the inner diameter gradually decreases from the upstream side toward the downstream side.

In one aspect of the present invention, the vertical shaft has a sliding surface of the lowest slide bearing device of the first slide bearing device and the second slide bearing device in the pump casing that is not immersed in pumped water. Drive in the state.

In one embodiment of the present invention, the pump casing includes an air pipe upstream of the impeller.

One aspect of the present invention has the effects listed below.
(1) The above friction due to the liquid film effect in the bearing generated on the sliding surface of the sliding bearing device that is always used in an underwater atmosphere against the frictional force generated on the sliding surface of the sliding bearing device used in the atmospheric atmosphere. A force in the direction opposite to the force is generated, and thereby the swing effect of the rotary shaft of the vertical pump can be suppressed as a whole by using the damping effect.
(2) Since the plain bearing device that is always used in an underwater atmosphere is a perfect circle bearing or a multi-arc bearing, the force of the liquid film effect in the bearing generated on the sliding surface is more effectively generated.
(3) Also, by providing a sliding bearing device whose sliding surface is always used in a liquid (underwater) atmosphere at a height higher than the discharge bowl of a vertical shaft pump, the impact of this sliding bearing device on pump performance is reduced. can do.
(4) Since the second sliding bearing device has the liquid receiving tank, the sliding portion of the sliding bearing of the second sliding bearing device can always be brought into contact with the liquid.
(5) Since the second slide bearing device has a plate member disposed above the slide bearing, liquid is received between the liquid receiving tank and the plate member so that the liquid contacts the entire sliding portion of the slide bearing. Can be held.
(6) Since the plate member is configured such that the inner diameter gradually decreases from the upstream side toward the downstream side, the liquid receiving tank and the plate member even if centrifugal force is applied to the liquid held in the liquid receiving tank. It is possible to suppress the liquid from being scattered from the space formed by the above.

It is a partial schematic diagram of a vertical shaft pump that performs a preliminary standby operation. It is a figure explaining the driving | running state of a prior | preceding standby driving | operation. It is sectional drawing which shows the whole conventional vertical shaft pump which performs the prior | preceding standby operation shown in FIG. FIG. 4 is an enlarged view of a sliding bearing device used in the sliding bearing device shown in FIG. 3. It is a perspective view of the slide bearing installed in the slide bearing apparatus shown in FIG. It is a typical sectional view showing the state of a rotating shaft, a sleeve, and a sliding bearing in a vertical shaft pump in which a sliding bearing device is arranged in a portion where the shaft swing becomes intense. It is a longitudinal cross-sectional view of the vertical shaft pump which concerns on this embodiment. It is sectional drawing which shows typically the force which acts on the sliding part of the sliding bearing apparatus operated by the air atmosphere which does not lubricate a sliding surface at the time of atmospheric operation. It is a figure which shows typically the force which acts on the sliding part of the sliding bearing apparatus used in the state in which a sliding surface is always underwater atmosphere. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a longitudinal cross-sectional view of a slide bearing apparatus. It is a longitudinal cross-sectional view of a slide bearing apparatus.

Hereinafter, an embodiment of a vertical shaft pump and a plain bearing device used therefor according to the present invention will be described with reference to FIGS. 7 to 12, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted. In the present specification, “upper part” and “lower part” are described as meaning the downstream side (“discharge” side in the figure) and the upstream side (“suction” side in the figure) of the liquid transferred by the vertical shaft pump, respectively. To do.

FIG. 7 is a longitudinal sectional view of the vertical shaft pump 3 according to the present embodiment. The vertical shaft pump 3 is a pump that may operate a rotating shaft in a state where there is no pumping target water in the pump casing. Some vertical shaft pumps perform a management operation in such a state, and others perform an aerial operation in a preceding standby operation. FIG. 7 illustrates a vertical shaft pump that performs a preliminary standby operation. Note that the management operation is an operation to check whether the pump can be operated normally when the pump is stopped due to the rainy season, and the inside of the pump casing is not dry. It is an operation performed in a state. The operation time may be several ten minutes to several tens of minutes.

As shown in FIG. 7, the vertical shaft pump 3 includes a discharge elbow 30 installed and fixed on the pump installation floor, a casing 29 connected to the lower end of the discharge elbow 30, and connected to the lower end of the casing 29 and the impeller 22. A discharge bowl 28 that stores therein (corresponding to an example of an impeller) and a suction bell 27 that is connected to the lower end of the discharge bowl 28 and sucks water are provided. The lower end of the suction bell 27 to the discharge end of the discharge elbow 30 is called a pump casing.

A through hole is provided in a side surface portion of the suction bell 27 on the inlet side of the impeller 22, and an air pipe 6 having an opening in contact with outside air is attached to the through hole. Thereby, this vertical shaft pump 3 changes the supply amount of the air supplied in the vertical shaft pump 3 through a through-hole according to a water level, and the amount of drainage of the vertical shaft pump 3 is controlled.

Rotating shaft 10 is arranged at a substantially central portion in the radial direction of casing 29, discharge bowl 28, and suction bell 27 of vertical shaft pump 3. An impeller 22 for sucking water into the pump is connected to one end side (suction bell 27 side) of the rotating shaft 10.

The rotary shaft 10 is a slide bearing device 32 fixed to the casing 29 via a support member at an appropriate position in the axial direction, and a slide bearing device fixed to the inner cylinder of the discharge bowl 28 via the support member. 33 and / or in the case of the rotating shaft 10 penetrating the impeller 22, the lower end portion of the rotating shaft 10 is supported by a plain bearing device 33 fixed to the casing 29 via a support member. One or more of the slide bearing device 33 and the slide bearing device 32 are arranged at one place, and a plurality of the slide bearing devices are combined.

The other end of the rotating shaft 10 extends to the outside of the vertical shaft pump 3 through a hole provided in the discharge elbow 30 and is connected to a driving machine such as an engine or a motor that rotates the impeller 22. A shaft seal 34 such as a floating seal, a gland packing, or a mechanical seal is provided between the rotary shaft 10 and a hole provided in the discharge elbow 30, and the water handled by the vertical pump 3 by the shaft seal 34 is supplied to the vertical pump. 3 is prevented from flowing out.

The drive will be installed on land so that maintenance and inspection can be performed easily. The rotation of the driving machine is transmitted to the rotary shaft 10 and the impeller 22 can be rotated. As the impeller 22 rotates, water is sucked from the suction bell 27, passes through the discharge bowl 28 and the casing 29, and is discharged from the discharge elbow 30.

By the way, the rotary shaft 10 of the vertical pump extends a long distance from the shaft seal 34 to the impeller in the casing. Although the degree of run-out varies depending on the position in the height direction,

plain bearing devices

32 and 33 are provided to support the rotary shaft 10 so as to suppress this run-out.

With regard to the arrangement of the sliding bearing device 32, the design of the rotating shaft 10 can be determined based on conditions such as the thickness, length, rotational speed, weight of the impeller, and the number of impellers based on experience or expedient calculation in the design stage. A position with a large run-out is determined, and based on this, a certain number of positions in the axial direction is determined. However, the arrangement position of the sliding bearing device 32 predicted as a position where the swing of the rotating shaft 10 is large may deviate from a position where the actual swing is large. Further, the arrangement position of the plain bearing device 32 cannot be corrected after the vertical shaft pump 3 is assembled.

In particular, as the rotating shaft 10 becomes longer, a portion with a large swing around the rotating shaft 10 is likely to occur at a plurality of locations. In order to suppress this, it is necessary to arrange more sliding bearing devices 32 along the axial direction of the rotary shaft 10. However, as a result, the number of cases where the arrangement position of the sliding bearing device 32 deviates from the position where the actual rotation of the rotary shaft 10 is large is increasing, and the size of the deviation is also increasing. That is, a part of the plurality of plain bearing devices is disposed at a so-called “node” position where the swing of the rotating shaft 10 is extremely small.

By the way, in the dry operation, when the slide bearing 1 in the slide bearing device 32 and the sleeve 11 attached to the rotary shaft 10 slide, the frictional force at the contact portion increases, and frictional heat is likely to be generated. There is concern about damage to the sleeve and the bearing at the contact portion.

In particular, the slide bearing device 32 provided in a place where the swing of the rotary shaft 10 is large has a larger bearing load. Therefore, the sleeve 11 attached to the sliding rotary shaft 10 is likely to be locally heated, and the vertical shaft Vibration and bearing load due to interference between the rotating body (rotating shaft 10 and sleeve 11) of the pump 3 and the fixed body (slide bearing 1) increase.

Therefore, the vertical shaft pump 3 according to the present embodiment includes a slide bearing device that is used as a part of the

slide bearing devices

32 and 33 in a state where the sliding surface is in an atmospheric atmosphere during atmospheric operation, and the rest is the atmospheric operation. Even so, a sliding bearing device is provided which is used in a state where the sliding surface is always in an underwater atmosphere. In other words, some of the

slide bearing devices

32 and 33 support the rotary shaft 10 in a state where there is no liquid on the sliding surface (bearing surface) of the slide bearing 1, and the remaining

slide bearing devices

32 and 33 are slide bearings. The rotating shaft 10 is configured to be supported in a state where liquid exists on one sliding surface (bearing surface). The sliding bearing device in which the sliding surface is used in an atmospheric atmosphere during the atmospheric operation is the sliding bearing device shown in FIGS.

As shown in FIG. 4, the plain bearing device has a sleeve 11 made of stainless steel, ceramics, sintered metal, surface-modified metal, or the like on the outer periphery of the rotating shaft 10. A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided on the outer peripheral side of the sleeve 11. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The plain bearing 1 is fixed to a support member 13 connected to a pump casing 29 and the like through a collar portion 12a by a bearing case 12 made of metal or resin. As shown in FIG. 5, the plain bearing 1 has a hollow cylindrical shape, the inner peripheral surface 1 a faces the outer peripheral surface of the sleeve 11, and the outer peripheral surface 1 b is fitted in the bearing case 12.

A slide bearing device in which the sliding surface is always used in an underwater atmosphere even during atmospheric operation is known in addition to a slide bearing described later (see FIGS. 9 and 10A to 10D), for example, as disclosed in Japanese Patent Laid-Open No. Hei. A plain bearing device disclosed in Japanese Patent Laid-Open No. 6-94035, Japanese Patent Laid-Open No. 2000-2190, Japanese Patent Laid-Open No. 2000-2191, or the like may be used.

The vertical shaft pump 3 shown in FIG. 7 performs the preceding standby operation described in FIG. That is, the vertical shaft pump 3 is operated in the state of the atmosphere in the casing 29, the discharge bowl 28, and the suction bell 27 when the pump is activated. At this time, some of the sliding

bearing devices

32 and 33 of the vertical shaft pump 3 are used in a state where the sliding surface is in an air atmosphere, and the rest are used in a state where the sliding surface is in an underwater atmosphere.

Here, the sliding

bearing devices

32 and 33 used in a state where the sliding surface is in an air atmosphere during the atmospheric operation and the sliding

bearing devices

32 and 33 used in a state where the sliding surface is in an underwater atmosphere. Explain whether such a phenomenon occurs.

FIG. 8 is a cross-sectional view schematically showing a force acting on a sliding portion of a sliding bearing device operated in an air atmosphere without liquid lubrication on a sliding surface during an atmospheric operation. FIG. 8 shows a cross section perpendicular to the axial direction of the rotating shaft 10. Here, the rotating side is the rotating shaft 10 and the sleeve 11 fitted to the rotating shaft 10. On the other hand, the fixed side is a slide bearing 1 that slides on the sleeve 11 and a bearing case 12 that supports the slide bearing 1. In FIG. 8, the dimension of the clearance between the sleeve 11 and the slide bearing 1 is shown enlarged for convenience.

When the rotating shaft 10 rotates, the sleeve 11 fixed to the rotating shaft 10 rotates. When this sliding bearing device is used in an air atmosphere, when the outer peripheral surface of the sleeve 11 comes into contact with the sliding bearing 1 at point A due to the swinging of the rotating shaft 10, the bearing reaction force F _AN is applied to the rotating shaft 10. appear. By this bearing reaction force _FAN , a frictional force _FAF is generated in a direction opposite to the rotational direction of the rotary shaft 10, and this frictional force _FAF causes a whirling vibration in the direction opposite to the rotational direction on the rotary shaft 10. Stabilization power.

It should be noted here that the magnitude of the frictional force F _AF that is the destabilizing force is the swing width perpendicular to the axial direction of the rotating shaft 10 (that is, the swing width in the radial direction of the rotating shaft 10). Depends on size. That is, the magnitude of the frictional force F _AF is relatively sensitive to whether the swing of the rotating shaft 10 is belly or node.

FIG. 9 is a diagram schematically showing the force acting on the sliding portion of the sliding bearing device used in a state where the sliding surface is always in an underwater atmosphere. FIG. 9 shows a cross section perpendicular to the axial direction of the rotating shaft 10. Also in this plain bearing device, the rotating side is the rotating shaft 10 and the sleeve 11 fitted thereto. On the other hand, the fixed side is a slide bearing 1 that slides on the sleeve 11 and a bearing case 12 that supports the slide bearing 1. The slide bearing device of FIG. 9 differs from the slide bearing device shown in FIG. 8 in that the atmosphere of the sliding portion of the sleeve 11 and the slide bearing 1 is underwater.

When the rotating shaft 10 rotates, the sleeve 11 fixed to the rotating shaft 10 rotates. When the sliding surface is in an underwater atmosphere, a liquid film is formed between the sleeve 11 and the slide bearing 1. At this time, the circumferential direction of the pressure nonuniformity due to the rotation of the rotary shaft 10 is generated in the liquid film, so that the radial fluid forces F _AR and the circumferential fluid force F _AT occurs in the rotation shaft 10. The effect of this phenomenon called the liquid film effect bearings, the force of the circumferential fluid force F _AT is the reverse rotation direction (reverse direction) to the frictional force F _AF generated by dry operation described in connection with FIG. 8 It is.

It should be noted that, dependent of circumferential fluid forces F _AT to the magnitude of the vertical deflection width in the axial direction of the rotary shaft 10 is smaller than the frictional force F _AF during dry operation in FIG. 8 That is. That is, the circumferential fluid force F _AT is runout of the rotating shaft 10 is not whether a clause or a belly, but rather affects the magnitude of the rotational speed.

The vertical shaft pump 3 of the present embodiment includes a plain bearing device that is used in a state where the sliding surface is in an atmospheric atmosphere during atmospheric operation as a part of the plurality of sliding

bearing devices

32 and 33, and the rest is the atmospheric operation. Even so, the sliding bearing device is used in a state where the sliding surface is always in an underwater atmosphere. As a result, during the atmospheric operation, the frictional force shown in FIG. 8 and the circumferential fluid force shown in FIG. 9 are generated simultaneously. For this reason, the forces that destabilize the rotating shaft 10 cancel each other in opposite directions, so that the swinging of the rotating shaft 10 is suppressed. Therefore, even when the sliding parts of the lowermost sliding bearings of the plurality of sliding

bearing devices

32 and 33 in the pump casing are not immersed in the pumping target pumping water, a pump that can be stably operated without problems is provided. Can be provided.

If the canceling force depends on the magnitude of the swing width perpendicular to the axial direction of the rotating shaft 10, that is, due to frictional forces opposite to each other disclosed in Patent Document 1 invented by the present inventors. When using a plain bearing device or the like that has a mechanism that generates a couple of forces to cancel and suppresses the swiveling of the rotating shaft 10, the slip is applied so that the offset is applied to the portion with the maximum swing width perpendicular to the axial direction. A bearing device should be arranged. However, as described above, it is difficult to accurately determine in advance which portion of the rotation shaft 10 has the maximum (antinode) or minimum (node) swing width, and the rotation shaft 10 There is a possibility that it is arranged at the position of a node having no runout width perpendicular to the axial direction. Once it is arranged at the node position, it becomes difficult to stop the rotation of the rotating shaft, and the position cannot be corrected and changed later.

However, in the vertical shaft pump 3 according to this embodiment, a part of the plurality of

slide bearing devices

32 and 33 is a slide bearing device in which the sliding portion of the slide bearing 1 is always in a liquid state, thereby rotating The countervailing couple acting on the shaft 10 is the circumferential fluid force. Unlike the generation of the canceling force due to the frictional force, this canceling force does not depend very much on the swing width perpendicular to the axial direction of the rotating shaft 10, but rather depends on the rotational speed, so that the installation position is rotated. Regardless of whether the shaft is an antinode or a node, a suitable canceling force can be generated regardless of where the sliding

bearing devices

32 and 33 are arranged on the rotating shaft 10. And the cancellation effect is large according to the high rotational speed of the rotating shaft 10 or high peripheral speed. Therefore, according to this embodiment, since the swing of the rotating shaft 10 is suppressed, there is no possibility of damage to the bearing and the sleeve due to local wear of the sliding portion of the rotating shaft 10 and frictional heat.

Incidentally, the liquid film effect in the bearing also depends on the cross-sectional shape of the slide bearing 1 cut in the radial direction. FIG. 10A to FIG. 10D are diagrams illustrating typical types of bearings according to a cross-sectional shape cut in the radial direction of the slide bearing 1. FIG. 10A shows a perfect circle bearing, FIGS. 10B and 10C show a multi-arc bearing, and FIG. 10D shows a tilting pad bearing. Specifically, FIG. 10B shows a two-arc bearing, and FIG. 10C shows an offset bearing. In FIG. 10A to FIG. 10D, the hatched portion represents the rotation shaft 10.

10A has a groove 41 substantially along the axial direction on the sliding surface, and quickly supplies water and lubricating oil in the axial direction of the slide bearing 2 through the groove 41. Note that the perfect circle bearing shown in FIG. 13A may not include the groove 41. The radius of the sliding surface of the portion where the groove 41 of the perfect circle bearing in FIG. 10A is not formed is r and the center is O. Of these three types of bearings, a perfect circle bearing is most likely to have a liquid film effect in the bearing, and therefore is also likely to generate a force.

The two-arc bearing shown in FIG. 10B also has a groove 41 on the sliding surface along the axial direction in the same manner as the perfect circle bearing in FIG. 10A. In the multi-arc bearing shown in FIGS. 10B and 10C, the radius of the slide bearing surface on which the rotary shaft 10 slides is basically r. It is configured. The two arc bearing shown in FIG. 10B and the offset bearing shown in FIG. 10C have centers O ₁ and O ₂ with respect to the two arcs. A multi-arc bearing having two or more arcs can also be constructed. Multi-arc bearings are not as good as perfect circle bearings among these three types, but they can still produce a liquid film effect in the bearings.

The tilting pad bearing shown in FIG. 10D has a plurality of sliding bearing surfaces called pads 43 that can be tilted around the rotating shaft 10 with the pivot 42 as a fulcrum, and surrounds the rotating shaft 10. The tilting pad bearing does not produce a liquid film effect in the bearing.

Conventionally, when the liquid film effect is caused by the sliding of the rotary shaft 10 in the liquid on the sliding surface of the slide bearing 1, an unstable force is applied to the rotary shaft 10 of the vertical pump 3, so that the liquid film effect is generated. In many cases, tilting pad bearings were used. However, in this embodiment, by using a part of the sliding bearing device in a state where the sliding portion is always in the liquid, the sliding bearing 1 having a dry sliding surface can be used during the dry operation of the preceding standby operation. A force opposite to the frictional force _FAF generated on the rotating shaft 10 is generated by the liquid film effect in the sliding bearing 1 whose sliding surface is always in water. For this reason, in this embodiment, a multi-arc bearing, more preferably a perfect circle bearing is used.

Next, of the sliding

bearing devices

32 and 33 in the pump casing, a sliding bearing device that is always used in an underwater atmosphere will be described with reference to FIGS. FIG. 11 is a longitudinal sectional view of the sliding bearing device 32. As shown in FIG. 11, the rotary shaft 10 extends above and below the slide bearing device 32, and a sleeve holding member 44 that holds the sleeve 11 is provided on the outer periphery of the rotary shaft 10. The sleeve 11 is provided on the outer periphery of the sleeve holding member 44. As the rotary shaft 10 rotates, the sleeve holding member 44 and the sleeve 11 rotate. The sleeve 11 has an outer peripheral surface as a sliding surface, and at least its outer surface is made of stainless steel, ceramics, sintered metal, or surface-modified metal.

A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is disposed on the outer peripheral side of the sleeve 11. The slide bearing 1 is a perfect circle bearing or a multi-arc bearing. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The plain bearing 1 is fixed to a support member 13 connected to a casing 29 (see FIG. 7) of a pump or an inner cylinder of a discharge bowl 28 by a bearing case 12 made of metal or resin.

The sleeve 11 and the sliding bearing 1 are further surrounded by a liquid receiving tank 45 and an inclined plate 46 (corresponding to an example of a plate member), and the sliding portion of the sleeve 11 and the sliding bearing 1 may be submerged in the liquid. A liquid reservoir 47 is formed. The liquid receiving tank 45 is positioned below the sleeve 11 and the slide bearing 1, and includes a rotating shaft side wall surface 45 a that is a substantially cylindrical wall having a diameter slightly larger than the diameter of the rotating shaft 10, and a substantially cylindrical wall having a larger diameter. It has a certain casing side wall surface 45b. The lower part of the rotating shaft side wall surface 45a and the casing side wall surface 45b are connected to each other to form a liquid receiving tank 45 that holds liquid. The upper portion of the casing side wall surface 45b is watertightly connected to the bearing case 12 that supports the slide bearing 1, and there is no water flow between the inside and the outside of the liquid receiving tank 45 at the height level of the connecting portion. Further, the outer shape of the casing side wall surface 45b has a convex spindle shape or a conical tip downward so as not to become resistance of pumping water that flows along the pumping, and gradually toward the upper side (downstream side). The outer diameter is expanding. With this shape, the streamlines of the water stream are less likely to be disturbed such as vortices, and pressure loss and fluid loss can be reduced.

The upper end of the rotating shaft side wall surface 45a extends to a position higher than the upper end portions of the sliding portions of the sleeve 11 and the slide bearing 1. The sleeve holding member 44 described above has a passage 48 so as not to interfere with the upper end of the rotary shaft side wall surface 45a of the liquid receiving tank 45. The sleeve holding member 44 includes an extending portion that extends downward from the attachment position of the sleeve 11.

The inclined plate 46 is a plate member configured in a substantially cylindrical shape as a whole, and is positioned above the sleeve 11 and the slide bearing 1 and has a structure in which the inner diameter of the inclined plate 46 gradually decreases from the lower part to the upper part. The lower part of the inclined plate 46 is watertightly connected to the bearing case 12 that supports the slide bearing 1, and there is no water flow between the inner side and the outer side of the inclined plate 46 at the height level of the connecting portion. The upper portion of the inclined plate 46 is opposed to a rotating body such as the sleeve holding member 44 with a slight clearance. Here, the upper end portion of the inclined plate 46 is located higher than the upper end of the rotary shaft side wall surface 45a described above.

By configuring the

plain bearing devices

32 and 33 in this way, when a liquid such as water is injected into the space surrounded by the liquid receiving tank 45 and the inclined plate 46, the liquid level is higher than the upper end of the rotary shaft side wall surface 45a. Now it is full, reaching the height of FL in the figure. Even if liquid is further injected, the upper end of the rotating shaft side wall surface 45a overflows. At this time, since the upper end of the rotating shaft side wall surface 45a extends to a position higher than the upper end of the sliding portion of the sleeve 11 and the slide bearing 1, the sleeve 11 and the slide bearing 1 are submerged.

In this state, when the rotating shaft 10, the sleeve holding member 44, and the sleeve 11 are rotated, the liquid is rotated along with the rotation, and a centrifugal force due to the rotation is obtained. However, since the inclined plate 46 is provided on the outer periphery of the liquid surface, scattering of the liquid to the outside due to the centrifugal force can be prevented. Although the liquid level rises on the inner wall surface of the inclined plate 46 due to the pressure of the centrifugal force, the direction of the liquid is changed to the rotating shaft 10 side by the inclined plate 46, and the upper portion of the inclined plate 46 has a slight clearance at the sleeve holding member 44. Therefore, it is possible to prevent the liquid from getting over the inclined plate 46 and being scattered outside.

Further, the outer shape of the inclined plate 46 and the sleeve holding member 44 has a convex spindle shape or a conical tip toward the upper side, and the outer diameter gradually increases downward (upstream side). . With this shape, the streamline of the pumped water flowing along it during pumping is less likely to cause turbulence and the like, and pressure loss and fluid loss can be reduced. Since the pumped water flows along the outer shape of the inclined plate 46 and the sleeve holding member 44 while suppressing disturbance of streamlines, foreign matters such as sand mixed in the pumped water flow upward (downstream) with the water flow. It becomes easy, and it can prevent flowing into the space surrounded by the liquid receiving tank 45 and the inclined plate 46 from the clearance between the inclined plate 46 and the sleeve holding member 44.

As described above, the liquid in the liquid receiving tank 45 is prevented from being scattered by centrifugal force. Further, since the atmosphere in the liquid receiving tank 45 is high in humidity, there is little decrease in liquid due to vaporization. Even if the liquid in the liquid reservoir 47 is reduced and the liquid level is lowered because the pump has not been operated for a long time, the pump is started by the extending portion extending downward from the mounting position of the sleeve 11 of the sleeve holding member 44. Since the liquid in the liquid reservoir 47 is initially subjected to centrifugal action and advances in the circumferential direction due to the centrifugal force, it is bent toward the bearing portion by the inner wall surface of the casing side wall surface 45b, so that water quickly reaches the bearing portion. be able to. Shortly thereafter, when the vertical shaft pump 3 pumps up, a part of the pumped water is supplied into the liquid receiving tank 45 and the liquid is replenished in sequence, so that special water supply equipment and devices for supplying the liquid to the liquid receiving tank 45 are required. In addition, it is possible to continue the rotation of the rotating body in a state where the liquid is always accumulated, that is, in a state where the sliding surface is immersed in the liquid.

The outer shape formed by the casing side wall surface 45b, the inclined plate 46 and the sleeve holding member 44 is preferably substantially spindle-shaped as a whole. By doing so, the water flow of the pumped water is hardly disturbed and the pressure loss can be reduced.

Further, in the

slide bearing devices

32 and 33, since the liquid receiving tank 45 and the inclined plate 46 are separate parts, the slide bearing 1 can be replaced by removing the liquid receiving tank 45. A hole for injecting liquid into the liquid receiving tank 45 or discharging the liquid from the liquid receiving tank 45 and a detachable plug for closing the hole are provided in the lower part of the liquid receiving tank 45 or the inclined plate 46. The liquid may be easily injected or discharged when necessary. Thereby, the inside of the liquid receiving tank 45 can be cleaned.

Although the slide bearing device 32 has been described above, the same configuration can be adopted for the slide bearing device 33 that is fixed to the inner cylinder of the discharge bowl 28 via a support member.

Next, the case where a sliding bearing device that is always used in an underwater atmosphere is used as the sliding bearing device 33 at the lower end of the rotating shaft 10 shown in FIG. FIG. 12 is a longitudinal sectional view of the sliding bearing device 33. The rotary shaft 10 passes through the impeller 22 (see FIG. 7) above the slide bearing device 33, and the position of the slide bearing device shown in FIG. 12 is located at the lower end of the rotary shaft 10.

A sleeve holding member 44 for holding the sleeve 11 is provided on the outer periphery of the lower end portion of the rotary shaft 10. The sleeve 11 is provided on the outer periphery of the sleeve holding member 44. The sleeve holding member 44 includes an extending portion that extends downward from the attachment position of the sleeve 11. As the rotary shaft 10 rotates, the sleeve holding member 44 and the sleeve 11 rotate. The sleeve 11 has an outer peripheral surface as a sliding surface, and at least its outer surface is made of stainless steel, ceramics, sintered metal, or surface-modified metal.

On the outer peripheral side of the sleeve 11, a slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided. The slide bearing 1 is a perfect circle bearing or a multi-arc bearing. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The plain bearing 1 is fixed to a support member 13 connected to a pump casing 29 (see FIG. 7) and the like by a bearing case 12 made of metal or resin.

The sleeve 11 and the slide bearing 1 are further surrounded by a liquid receiving tank 45 and an inclined plate 46, thereby forming a liquid reservoir 47 in which the sliding portion of the sleeve 11 and the slide bearing 1 is submerged.

The liquid receiving tank 45 is positioned below the sleeve 11 and the slide bearing 1 and has a circular container shape that is depressed in the center. The peripheral edge of the liquid receiving tank 45 is connected and fixed to the support member 13 and / or the bearing case 12 in a watertight manner. At the height level of the connecting portion, there is no water going in and out of the liquid receiving tank 45. Further, the outer shape of the water receiving tank 45 has a convex spindle shape or a conical tip toward the bottom (upstream side) so as not to resist the pumping of the water flowing along the pumping pump, and the top (downstream side). The outer diameter is gradually expanding. With this shape, the streamlines of the water stream are less likely to be disturbed such as vortices, and pressure loss and fluid loss can be reduced.

The inclined plate 46 is positioned so as to cover the upper part from the sleeve 11 and the slide bearing 1 and has a structure in which the inner diameter of the inclined plate gradually decreases from the lower part to the upper part. The lower part of the inclined plate 46 is fixed to the bearing case 12 in a watertight manner, and there is no water flow between the inner side and the outer side of the inclined plate 46 at the height level of the connecting portion. The upper part of the inclined plate 46 is opposed to the foreign matter intrusion prevention plate 49 with a slight clearance. The foreign matter intrusion prevention plate 49 is a disk-shaped member fixed to the outer peripheral surface of the rotary shaft 10 and is disposed so as to cover the inclined plate 46 from above. Thereby, the penetration | invasion of the sand etc. which inhibits the sliding of the sleeve 11 and the slide bearing 1 into the inner side of the inclination board 46 and the liquid receiving tank 45 is suppressed.

In the space surrounded by the liquid receiving tank 45 and the inclined plate 46, a liquid such as water can be injected up to the height of FL in the figure that overflows the upper end of the inclined plate 46. In other words, the liquid can be injected so as to fill the space formed by the inclined plate 46 and the liquid receiving tank 45. By positioning the liquid level higher than the upper end of the sliding portion of the sleeve 11 and the slide bearing 1, the sleeve 11 and the slide bearing 1 can be submerged.

In this state, when the rotating shaft 10, the sleeve holding member 44, and the sleeve 11 are rotated, the water is rotated along with the rotation, and a centrifugal force due to the rotation is obtained. However, since there is an inclined plate 46 on the outer peripheral side of the liquid surface, scattering of the liquid to the outside due to centrifugal force can be prevented. Although the liquid level rises on the inner wall surface of the inclined plate 46 due to the pressure of the centrifugal force, the direction of water is changed to the rotating shaft 10 side by the inclined plate 46, and the upper part of the inclined plate 46 is a foreign matter intrusion prevention plate with a slight clearance. Since it is opposed to a rotating body such as 49, it is possible to prevent water from getting over the inclined plate 46 and splashing outside.

In addition, the outer shape of the inclined plate 46 and the foreign matter intrusion prevention plate 49 has a spindle shape or a conical tip that protrudes upward (downstream side), and gradually decreases in outer diameter toward the lower side (upstream side). Is expanding. With this shape, the streamline of the pumped water flowing along it during pumping is less likely to cause turbulence and the like, and pressure loss and fluid loss can be reduced. Since the pumping water flows while suppressing the disturbance of the streamline along the outer shape of the inclined plate 46 and the foreign matter intrusion prevention plate 49, foreign matters such as sand mixed in the pumped water easily flow upward along with the water flow, The clearance between the inclined plate 46 and the foreign matter intrusion preventing plate 49 can be prevented from flowing into the space surrounded by the liquid receiving tank 45 and the inclined plate 46.

As described above, the water in the liquid receiving tank 45 is prevented from being scattered by centrifugal force. Further, since the atmosphere of the liquid receiving tank 45 is high in humidity, there is little decrease in the liquid due to vaporization. Even if the liquid in the liquid reservoir 47 is reduced and the liquid level is lowered because the pump has not been operated for a long time, the pump is started by the extending portion extending downward from the mounting position of the sleeve 11 of the sleeve holding member 44. Since the liquid in the liquid reservoir 47 is initially subjected to centrifugal action and advances in the circumferential direction due to the centrifugal force, it is bent toward the bearing portion by the inner wall surface of the casing side wall surface 45b, so that water quickly reaches the bearing portion. be able to. Shortly thereafter, when the vertical shaft pump 3 pumps up, a part of the pumped water is supplied into the liquid receiving tank 45 and the liquid is replenished in sequence, so that special water supply equipment and devices for supplying the liquid to the liquid receiving tank 45 are required. In addition, it is possible to continue the rotation of the rotating body in a state where liquid is always accumulated, that is, in a state where the sliding surface is immersed in water.

Further, it is preferable that the outer shape formed by the liquid receiving tank 45, the inclined plate 46, and the foreign matter intrusion prevention plate 49 is substantially a spindle shape as a whole. By doing so, the water flow of the pumped water is hardly disturbed and the pressure loss can be reduced.

Further, in the

slide bearing devices

As described above, the plurality of

plain bearing devices

32 and 33 that support the rotating shaft 10 are provided, and a part of the plurality of

plain bearing devices

32 and 33 is in an air (dry) atmosphere during the air operation. The vertical shaft pump 3 for standby standby has been described as a sliding bearing device to be used, and the rest as a sliding bearing device to be used in a state where the sliding surface is always in a liquid (underwater) atmosphere. Further, as examples of the sliding

bearing devices

32 and 33 used in a state where the sliding surface is always in a liquid (underwater) atmosphere, (1) an example in which the sliding surface is disposed inside the casing 29, and (2) the rotating shaft 10 The example arrange | positioned in a lower end part was demonstrated. These sliding

bearing devices

32 and 33 used in a liquid (underwater) atmosphere always have sliding surfaces when the rotary shaft 10 of the vertical pump 3 swings at any position of the rotary shaft 10 of the vertical pump 3. It is possible to cancel the couple of forces generated on the sliding surface of the slide bearing device used in a state where the air is in an air (dry) atmosphere. In particular, since the liquid film effect can cope with an increase in the number of rotations, this plain bearing device is suitable for the vertical pump 3 for the advance standby operation in which the number of rotations is increased and the length of the rotation shaft is increased.

Further, the

plain bearing devices

32 and 33 shown in FIG. 11 and FIG. 12 do not require any additional equipment such as equipment for supplying water to the protective pipe and maintain it, compared to the case where the conventional protective pipe is used. It becomes easy. Further, the vertical shaft pump 3 according to the present embodiment also uses a sliding bearing device in which the sliding surface is in a dry state during dry operation. Therefore, all the sliding bearing devices are stored in the water so that the sliding surface is underwater. Compared with the case of replacing with a plain bearing device in a state existing in the above, the cost can be reduced, maintenance is facilitated, and the influence on the pump performance can be reduced.

However, in the above two examples, there are things to consider regarding the influence of others. A plain bearing device used in a state where the sliding surface is always in a liquid (in water) atmosphere requires a certain size in order to maintain its function. Therefore, there is a problem that such a plain bearing device tends to narrow the flow passage area of the vertical shaft pump 3 or become a fluid resistance. When the sliding bearing device shown in FIG. 12 is arranged at the lower end of the rotary shaft 10, the swing of the rotary shaft 10 during the dry operation of the vertical shaft pump 3 for preceding standby operation can be suppressed, and maintenance is facilitated. Although it is excellent in terms of making it, the flow passage area of the suction port of the vertical shaft pump 3 is narrowed. For this reason, we are anxious about the fall of the performance by the fall of the suction pressure at the time of pumping, and generation | occurrence | production of cavitation. However, if the sliding bearing 1 is a perfect circle bearing shown in FIG. 10A or a multi-circular bearing shown in FIG. 10B, the sliding bearing 1 can be made more compact than the tilting pad bearing shown in FIG. 10D.

On the other hand, when the slide bearing device 32 is arranged at a position higher than the discharge bowl 28 (downstream position), the slide bearing device 32 narrows the flow path area of the vertical shaft pump 3, but this position is under discharge pressure. Therefore, there is no concern about the reduction of the suction pressure and the occurrence of cavitation described above. Further, the

slide bearing devices

32 and 33 arranged in the inner cylinder of the discharge bowl 28, a portion immediately above the discharge bowl 28, and the like do not significantly affect the flow. Even if the arrangement position is limited in this way, it is possible to sufficiently generate a couple that cancels the couple generated in the sliding bearing device having a dry sliding surface during the dry operation.

As described above, the

slide bearing devices

32 and 33 whose sliding surfaces are always used in a liquid (underwater) atmosphere are disposed at the position where the rotary shaft 10 is swung during the dry operation of the vertical shaft pump 3 for the preliminary standby operation. From the viewpoint of suppressing the rotation and not affecting the pump performance at the time of pumping, it is preferable to arrange in the discharge bowl 28 or higher.

As described above, the embodiment of the present invention has been described mainly using the vertical shaft pump that performs the preliminary standby operation as an example, but the vertical shaft pump 3 rotates the rotating shaft in a state where there is no water to be pumped in the pump casing. A pump that may be operated in such a state, and a pump that performs a management operation in such a state is also included. The above-described embodiments of the present invention are intended to facilitate understanding of the present invention, and do not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof. In addition, any combination or omission of each component described in the claims and the specification is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect can be achieved. is there.

DESCRIPTION OF SYMBOLS 1 ... Slide bearing 3 ... Vertical shaft pump 6 ... Air pipe 10 ... Rotating shaft 11 ... Sleeve 22 ... Impeller 29 ... Casing 30 ... Discharge elbow 32 ... Slide bearing device 33 ... Slide bearing device 34 ... Shaft seal 44 ... Sleeve holding member 45 ... Receiving tank 46 ... Inclined plate

Claims

A vertical shaft pump comprising: a rotary shaft; a pump casing that houses at least a part of the rotary shaft; and an impeller attached to the rotary shaft,
A plurality of plain bearing devices for supporting the rotating shaft;
A part of the plurality of plain bearing devices is a first plain bearing device that is used in a state where the sliding surface is in an air atmosphere during air operation,
The remainder of the plurality of plain bearing devices is a vertical shaft pump that is a second plain bearing device that is used in a state where the sliding surface is always in a liquid atmosphere.
The vertical shaft pump according to claim 1,
The second plain bearing device is a vertical shaft pump having a perfect circle bearing or a multi-arc bearing.
In the vertical shaft pump according to claim 1 or 2,
A discharge bowl containing the impeller,
The second sliding bearing device is a vertical shaft pump provided at a height higher than the discharge bowl.
In the vertical shaft pump according to claims 1 to 3,
The second plain bearing device is:
A plain bearing for supporting the rotating shaft;
A vertical shaft pump comprising: a liquid receiving tank that holds the liquid so that a sliding portion of the slide bearing contacts the liquid.
In the vertical shaft pump according to claim 4,
The second sliding bearing device is a vertical shaft pump disposed above the sliding bearing and having a plate member for holding the liquid together with the liquid receiving tank.
In the vertical shaft pump according to claim 5,
The plate member has a cylindrical shape, and is configured to have an inner diameter that gradually decreases from the upstream side toward the downstream side.
In the vertical shaft pump according to any one of claims 1 to 6,
A vertical shaft pump that operates in a state in which the sliding surface of the lowest slide bearing device of the first slide bearing device and the second slide bearing device in the pump casing is not immersed in pumped water.
In the vertical shaft pump according to any one of claims 1 to 7,
The pump casing is a vertical pump including an air pipe on the upstream side of the impeller.