JP7561680B2 - Submersible bearing structure, vertical pump, pump system, and lubricating liquid supply method - Google Patents

Description

The present invention relates to a submersible bearing structure for a vertical pump that pumps liquids such as river water and wastewater. In particular, the present invention relates to a submersible bearing structure that can prevent the bearings and shaft sleeves that support the rotating shaft from operating in a dry state during initial operation, such as at start-up, in a pre-standby operation type vertical pump. The present invention further relates to a vertical pump that includes the submersible bearing structure, a pump system, and a method for supplying lubricating liquid.

An example of background technology for recent standby-type vertical pumps is described below. In recent years, urbanization has led to a decrease in green space and an increase in the use of concrete or asphalt on road surfaces. This has resulted in the heat island phenomenon, and localized heavy rainfall, known as "guerilla downpours," occurs frequently in urban areas. On concrete or asphalt road surfaces, large amounts of localized rainfall are led directly into waterways without being absorbed into the ground. As a result, large amounts of rainwater flow into the drainage station in a short period of time.

The large amounts of rainwater brought about by these frequent torrential downpours need to be drained quickly. Therefore, the vertical pumps installed at drainage stations are operated in advance, before the rainwater reaches the station, in a standby mode. This prevents flooding damage caused by a delay in starting the pump. Specifically, in standby mode, the pump is operated from a low water level before the water level in the suction tank reaches a level at which pumping can be performed. Therefore, the pump is operated without pumping water until the water level in the suction tank reaches the pumping level (hereinafter referred to as air operation). If a protective pipe is present, water is supplied to the bearings that support the pump's rotating shaft (in other words, the main shaft) and the shaft sleeve of the rotating shaft, so the bearings and shaft sleeve are kept wet.

In vertical pumps that are operated in advance standby mode, a protective tube method may be used in which the entire rotating shaft is covered in a protective tube, including the rubber bearings. In the protective tube method, water is supplied into the protective tube from an elevated water tank or the like. The water can be circulated between the elevated water tank or the like and the protective tube. In this way, water can be supplied to the bearings and bearing sleeves even during air operation.

In vertical pumps with protective pipes such as those described above, water may not flow through the protective pipe due to a power outage causing a water supply cut or a malfunction of the pump connected to the elevated water tank. If the pump is operated without water being supplied to the protective pipe, the rubber bearings will be damaged by friction. Therefore, conventionally, if water does not flow through the protective pipe, the pump operation is stopped and an inspection is carried out. In other words, conventional vertical pumps with protective pipes have the problem that the main pump cannot operate due to a malfunction of the auxiliary equipment.

As described above, the protective pipe system requires many auxiliary devices such as water supply pumps, which reduces the reliability of the equipment. Therefore, it is desirable to simplify the mechanism for injecting water into the protective pipe.

During air operation of a vertical pump, the bearing and shaft sleeve slide in the air under high friction. In particular, among vertical pumps, pumps in standby operation need to be operated in the air before pumping starts and the bearings are lubricated with water. In order to enable air operation of the pump while keeping the bearings dry, for example, ceramics or resins are used for the submerged bearings and cemented carbide or thermal spray coating is used for the shaft sleeve. However, if the bearings and shaft sleeves are dry during operation of the pump, the temperature of the bearings will rise due to high friction, and there is a risk that the temperature of the bearings themselves or the materials around the bearings will exceed the limit temperature. In addition, it is necessary to use special resins or ceramics with a low friction coefficient to suppress the effects of friction.

To eliminate such material or design limitations, the following techniques have been proposed:

Specifically, Japanese Patent Laid-Open Publication No. 2000-2190 (Patent Document 1) describes a plain bearing device for a vertical shaft pump that includes a bearing member housed in a bearing casing and a shaft sleeve that is attached to the main shaft and slides against the bearing member, and the shaft sleeve is provided with a bottomed, annular water storage section with an opening at the top through which pumped water can enter and exit, and the bearing member is submerged in the bottomed, annular water storage section.

JP 2000-266042 A (Patent Document 2) describes a plain bearing device for a vertical shaft pump that includes an annular hard bearing member, a shaft sleeve that is attached to the main shaft and slides against the bearing member, an annular metallic back metal that is fitted around the outer periphery of the annular hard bearing member, an annular buffer member that is fitted around the outer periphery of the back metal, and an annular metallic shell that is fitted around the outer periphery of the buffer member, the back metal having an annular water storage section with a concave cross section and an upper opening that can store pumped water.

JP 5-44689 A (Patent Document 3) describes a drainage pump bearing structure that includes a ceramic bearing made of porous SiC impregnated with lubricating oil, a sleeve that is attached to the main shaft and slides against the ceramic bearing, and a ceramic shaft cushioning material that supports the ceramic bearing via a ceramic shaft back metal, forming a gap on the surface where the ceramic bearing and the ceramic shaft back metal come into contact with each other, and supplying oil or water to the gap via a pipe.

JP 2017-166423 A (Patent Document 4) describes a vertical pump equipped with a cyclone separator that filters a portion of the water pumped by the pump, and a flow meter and differential pressure gauge to ensure that the purified water is sent to the submerged bearing.

In the technology described in Patent Document 1, a bottomed annular water storage section with an opening at the top through which pumped water can enter and exit is provided on a shaft sleeve that rotates integrally with the main shaft, and the bearing member is submerged in the bottomed annular water storage section. This causes problems, however, such as the difficulty in securing the amount of water required to submerge the bearing member in the water storage section, and the difficulty in securing the required amount of water, particularly when the pump is started, because the water evaporates due to frictional heat from the bearing section. In addition, there is a problem that sand and mud contained in the pumped water accumulate in the water storage section, damaging the sliding parts (in other words, the sliding surfaces) of the bearing member and shaft sleeve.

In the technology described in Patent Document 2, the back metal is provided with a ring-shaped water storage section with a concave cross section that has an upper end opening capable of storing pumped water, and pumped water is stored in the storage section. The back metal is cooled by the water cooling effect of this stored water and the cooling effect of the heat of vaporization when the stored water evaporates, and the bearing member is cooled via the back metal. However, since the sliding part between the bearing member and the shaft sleeve is not directly cooled with water, there is a problem that it cannot be cooled sufficiently. Also, as with Patent Document 1, when the pump is started, water evaporates due to frictional heat from the bearing part, so there is a problem that it is difficult to secure the required amount of water.

In the technology described in Patent Document 3, a gap is formed on the surface where the ceramic bearing and the ceramic shaft back metal come into contact with each other, and oil or water is supplied to the gap, causing the oil or water in the gap to seep through the pores of the porous SiC onto the sliding surface of the bearing, lubricating the sliding surface. However, since the sliding part between the bearing and the sleeve is not directly cooled with water, there is a problem that it cannot be cooled sufficiently.

In the technology described in Patent Document 4, the cyclone separator is unable to remove all of the tiny foreign objects, which can lead to early wear of the submerged bearings to which the water is supplied, potentially making it impossible to operate the pump.

JP 2000-2190 A JP 2000-266042 A Japanese Patent Application Publication No. 5-44689 JP 2017-166423 A

One embodiment of the present invention has been made in consideration of the above circumstances, and aims to provide a submerged bearing structure for a vertical pump, and a vertical pump including the same, which can prevent the bearing and shaft sleeve from operating in a dry state by supplying lubricating liquid between the bearing and shaft sleeve during initial operation. Another embodiment of the present invention aims to provide a pump system including the vertical pump. Another embodiment of the present invention aims to provide a method for supplying lubricating liquid in the pump system.

According to one embodiment of the present invention, there is provided an underwater bearing structure that supports a rotating shaft on which an impeller of a vertical pump is attached, the underwater bearing structure comprising an underwater bearing member that rotatably supports the rotating shaft, and a protective tube having an outer wall to which the underwater bearing member is fixed, the protective tube having an inner wall provided inside the outer wall, the outer wall and the inner wall defining a liquid supply receiver having a first opening that can receive lubricating liquid for the underwater bearing member from above, the liquid supply receiver being disposed above the underwater bearing member, and the inner wall having a second opening that allows the flow of lubricating liquid from the liquid supply receiver.

1 is a schematic diagram showing an overall outline of a vertical pump according to an embodiment of the present invention; 1 is a cross-sectional view showing an example of an underwater bearing structure according to an embodiment of the present invention. 4 is a cross-sectional view showing another example of an underwater bearing structure according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing another example of an underwater bearing structure according to an embodiment of the present invention. FIG. FIG. 5 is a transverse cross-sectional view of the bearing shown in FIG. 1 is a schematic diagram showing an overall overview of a pump system according to an embodiment of the present invention; FIG. 7 is a schematic partial view of the outlet pipe shown in FIG. 6 .

The following describes an embodiment of the present invention with reference to the drawings. Note that the following description is merely an example, and is not intended to limit the technical scope of the present invention to the following embodiment. In the drawings, the same or corresponding components are given the same reference numerals, and duplicate descriptions are omitted. In the following description, terms indicating directions such as "upper" and "lower" refer to the directions in the installed state of the vertical pump as shown in FIG. 1, etc.

1 is a diagram showing an overall outline of a vertical shaft pump 100 according to an embodiment of the present invention. The vertical shaft pump 100 includes a rotating shaft 101 extending in the vertical direction, an impeller 102 attached to the lower end of the rotating shaft 101, and a driver (not shown) that is provided at the upper end of the rotating shaft 101 and drives the rotating shaft 101 to rotate. The vertical shaft pump 100 is a pump that pumps water from below to above through a pump casing 108 by rotating the impeller 102.

The vertical pump 100 is also a type of pump that performs standby operation prior to the start of pump operation. In standby operation prior to the start of pump operation, the impeller 102 is first rotated in an air state before the impeller 102 is submerged (air operation) based on rainfall information, etc., regardless of the suction water level. When the water level rises to the position of the impeller 102, the operation state of the vertical pump 100 changes from an operation in which the impeller 102 stirs the handled liquid (in other words, the liquid transported by the vertical pump 100) (air-water stirring operation) to an operation in which the air supplied from the intake port is sucked in together with the handled liquid while gradually increasing the amount of liquid (air-water mixing operation), and then to a normal operation (steady operation) in which the handled liquid is discharged at a rated flow rate.

The vertical pump 100 also includes a substantially cylindrical pump casing 108 that surrounds the rotating shaft 101, impeller 102, and guide vanes 103. The guide vanes 103 are fixed to the inner circumferential surface of the pump casing 108 and support a protective tube 122, which will be described later. The guide vanes 103 also convert the swirling component of the water flow pumped by the impeller 102 into a vertically upward component.

The pump casing 108 can include a suction bell 104 that forms a pump suction port, and a discharge bowl 105 that houses the guide vanes 103 and the bearing member 120A. The suction bell 104 is formed in a bellmouth shape. The discharge bowl 105 is formed in a substantially cylindrical shape so as to surround the guide vanes 103, and is formed so that the diameter of the cylinder expands upward along the extension direction of the rotating shaft 101 and then contracts.

The pump casing 108 may also include a suspension pipe 106 that is disposed above the discharge bowl 105 and extends to a desired height. The suspension pipe 106 is formed in a cylindrical shape that surrounds the rotating shaft 101. The liquid handled by the vertical pump 100 is pumped through the suspension pipe 106. The pump casing 108 may also include a discharge elbow 107 that is connected to the suspension pipe 106. The discharge elbow 107 is formed so as to extend vertically along the rotating shaft 101 and then change direction to a substantially horizontal direction. Therefore, the pumped liquid is changed in flow direction to a substantially horizontal direction by the discharge elbow 107. The suction bell 104, the discharge bowl 105, the suspension pipe 106, and the discharge elbow 107 are appropriately connected by flanges to form the pump casing 108.

The vertical shaft pump 100 has an underwater bearing structure that rotatably supports the rotating shaft 101. The underwater bearing structure has an underwater bearing member 120 that supports the rotating shaft 101. In this embodiment, two underwater bearing members (hereinafter, bearing members) 120A and 120B are provided. However, the number of bearing members 120 in the vertical shaft pump 100 is not particularly limited.

The underwater bearing structure includes a protective tube 122. The protective tube 122 is used to supply lubricating liquid (e.g., tap water) from outside the pump casing 108 to each of the bearing members 120A and 120B. The protective tube 122 is a substantially cylindrical member to which the bearing members 120A and 120B are fixed. The protective tube 122 is fixed at the shaft seal portion 109 of the discharge elbow 107 and extends to below the bearing member 120A in the discharge bowl 105.

The bearing members 120A and 120B are sliding bearings spaced apart from each other along the rotating shaft 101. A shaft sleeve, not shown in FIG. 1, may be attached to the rotating shaft 101 so as to be in sliding contact with the bearing surfaces of the bearing members 120A and 120B. The bearing member 120A may be disposed at the height of the discharge bowl 105 and fixed to the protective tube 122. The bearing member 120B may be disposed at a higher position than the bearing member 120A. The bearing member 120B may be supported by a support member 110 fixed to the pump casing 108.

The suspension pipe 106 is inserted into the opening hole 1101 of the installation floor 1100. In this manner, the vertical pump 100 can be fixed and installed on the installation floor 1100 at the lower part of the discharge elbow 107.

1, the protective tube 122 has a liquid supply line 1102A, one end of which is connected to a lubricating liquid supply source 1104 and the other end of which is connected to the protective tube 122. The supply source 1104 may be a tank installed outside the pump casing 108 for receiving lubricating liquid such as tap water. The lubricating liquid is supplied from the supply source 1104 to the protective tube 122 through the liquid supply line 1102A. The protective tube 122 also has a discharge line 1102B, one end of which is connected to the lubricating liquid supply source 1104 and the other end of which is connected to the protective tube 122. The lubricating liquid is discharged from the protective tube 122 through the discharge line 1102B and collected in the supply source 1104. In this embodiment, the protective tube 122 is connected to the liquid supply line 1102A through the wall surface of the discharge elbow 107 at a portion above the uppermost bearing member 120B (the shaft seal portion of the discharge elbow 107 in the illustrated example). In this embodiment, the lubricating liquid from the supply source 1104 can be pumped to the protective tube 122 depending on the installation height of the supply source 1104.

The lubricating liquid supplied to the protective tube 122 from the liquid supply line 1102A flows sequentially from the bearing member 120B to the bearing member 120A. The protective tube 122 forms a bowl portion 129 in the discharge bowl 105 of the pump casing 108. The inflow of lubricating liquid from the liquid supply line 1102A fills the inside of the protective tube 122 with water. When the protective tube 122 is full, the lubricating liquid flows out of the protective tube 122 through the discharge line 1102B.

The discharge pipe 1102B is connected to the space 128 at the top of the bowl portion 129 of the protective pipe 122. The lubricating liquid that changes its flow upward in the space 128 is collected in the supply source 1104 via the discharge pipe 1102B.

Next, referring to FIG. 2, a partial cross-sectional view showing an example of an underwater bearing structure according to this embodiment is shown. Note that, here, the bearing member 120B is described as an example of the bearing member 120, but a substantially similar configuration can be applied to the bearing member 120A. As shown in FIG. 2, the bearing member 120B can include a bearing 2120 including a bearing surface that slides against the shaft sleeve 101B of the rotating shaft 101, and a bearing case 2122 to which the bearing 2120 is attached. The bearing member 120B can also include a cushioning material 2124 disposed between the bearing 2120 and the bearing case 2122. The specific shape of the bearing member 120B is not limited to that shown in the figure.

The protective tube 122 has an outer wall 1122 to which the bearing member 120B is fixed. In this embodiment, the bearing case 2122 of the bearing member 120B is arranged to form a part of the tube wall of the protective tube 122. Specifically, as shown in FIG. 2, the protective tube 122 is divided into upper and lower parts with the bearing member 120B in between. For ease of understanding, in FIG. 2, the part of the protective tube 122 that is fixed to the upper part of the bearing member 120B is labeled with the symbol 122A, and the part that is connected to the lower part of the bearing member 120B is labeled with the symbol 122B. However, the protective tube 122 does not have to be divided as shown. For example, the outer peripheral surface of the bearing case 2122 may be fixed to the inner peripheral surface of the outer wall 1122 of the protective tube 122 so that the entire bearing member 120B is located inside the protective tube 122.

The protective tube 122 also has an inner wall including an inner peripheral wall 1124 and a bottom wall 1126 provided inside the outer wall 1122. In the illustrated example, the inner wall is a member having a substantially L-shaped cross section. Specifically, the inner wall includes the inner peripheral wall 1124 extending substantially vertically, and the bottom wall 1126 extending laterally so as to connect the inner peripheral wall 1124 and the outer wall 1122. However, the specific shape of the inner wall is not limited to this. The inner wall may extend, for example, in a curved shape protruding inward from the outer wall 1122, without distinction between the inner peripheral wall 1124 and the bottom wall 1126.

In this embodiment, the outer wall 1122, the inner peripheral wall 1124, and the bottom wall 1126 form a liquid supply receiving portion 1128 having a first opening 1130 in the protective tube 122. The first opening 1130 opens upward so as to be able to receive the lubricating liquid supplied to the protective tube 122. In this way, a portion of the lubricating liquid supplied to the protective tube 122 can be stored in the liquid supply receiving portion 1128. The bottom wall 1126 of the liquid supply receiving portion 1128 is positioned higher than the bearing member 120B.

2 has a second opening 1132 near the bottom wall 1126. The second opening 1132 allows the flow of lubricating liquid from the liquid supply receiving portion 1128. As the second opening 1132, a plurality of openings 1132 formed at intervals in the circumferential direction of the protective tube 122 may be provided. The size and number of the second openings 1132 are determined so that the flow rate of the lubricating liquid exiting the second openings 1132 (if there are a plurality of second openings 1132, the total flow rate of the lubricating liquid exiting the plurality of second openings 1132) does not exceed the flow rate of the lubricating liquid entering from the first opening 1130. The second opening 1132 may be a single opening extending continuously around almost the entire circumference of the protective tube 122.

The second opening 1132 can be provided with a flow rate limiting member 1131 that limits the flow rate of the lubricating liquid coming out of the liquid supply receiving portion 1128. As the flow rate limiting member 1131, for example, a liquid-permeable sheet or mesh member made of metal or resin having fine holes can be used.

The flow rate restricting member 1131 allows the lubricating liquid to drip, for example, in the form of droplets as shown in the figure. However, if multiple second openings 1132 are formed, it is also possible to reduce the dimensions of each of the second openings 1132 and form them as small holes (for example, slits).

During operation of the vertical shaft pump 100, the lubricating liquid in the supply source 1104 is continuously supplied from the supply liquid line 1102A to the protective tube 122. During this time, a portion of the lubricating liquid enters the supply liquid receiving section 1128 from the first opening 1130. The lubricating liquid flows out at a minute flow rate from the second opening 1132 through the flow rate limiting member 1131 and accumulates in the supply liquid receiving section 1128. During operation of the vertical shaft pump 100, a situation may occur in which the lubricating liquid is not supplied to the protective tube 122 due to a liquid leak from the supply source 1104 or the supply liquid line 1102A, etc. In this embodiment, even if the lubricating liquid is no longer supplied to the protective tube 122, the lubricating liquid that has been accumulated in the supply liquid receiving section 1128 flows or drips onto the bearing surface of the bearing member 120B through the second opening 1132. Although the volume of the liquid receiving section 1128 is limited, by providing a flow rate limiting member 1131 in the second opening 1132, a small amount of lubricating liquid can be supplied to the bearing surface for a relatively long period of time. The supply flow rate to the bearing surface can be about several ml per minute.

As shown in FIG. 2, the upper end 2120a of the bearing surface may be tapered. As described above, a minute amount of lubricating liquid may be dripped in the form of droplets. The droplets of lubricating liquid leaving the second opening 1132 can be smoothly guided to the bearing surface along the slope of the upper end 2120a of the bearing surface. However, a tapered surface such as that described above does not necessarily have to be provided, and the bearing surface may be flat overall.

The second opening 1132 is preferably formed below the center of the height of the liquid receiving portion 1128, preferably near the bottom wall 1126. Depending on the specific shape and dimensions of the bearing member 120B and the liquid receiving portion 1128, the second opening 1132 may be provided in the bottom wall 1126.

In addition, in this embodiment, the blades 130 can be attached to the rotating shaft 101 at a position lower than the bearing surface of the bearing member 120B. Wind pressure can be generated by the blades 130 that rotate together with the rotating shaft 101. This wind pressure pushes the lubricating liquid that has passed through the bearing surface back upward, and the pushed-back lubricating liquid can provide lubrication. The wind pressure can also cool the bearing surface.

Figure 3 shows another example of the flow rate limiting member. In this example, the flow rate limiting member can be a tubular member 140 that is placed in the second opening 1132. One end of the tubular member 140 opens in the liquid supply receiving portion 1128. The tubular member 140 is also bent downward so that the other end opens near the bearing surface (in the illustrated example, the tapered surface 2120a). This allows a minute flow rate of lubricating liquid to be supplied from a position close to the bearing surface.

Figure 4 shows another example of the flow rate limiting member. In this example, the second opening 1132 is formed in the bottom wall 1126. The tubular member 150 arranged in the second opening 1132 constitutes the flow rate limiting member. The tubular member 150 passes through the inside of the bearing member 120B and opens at the bearing surface 2120b. In the example of Figure 4, the tubular member 150 includes a first pipe 152 extending from the second opening 1132 to the inside of the bearing case 2122 and a plurality of second pipes 154 connected to the first pipe 152. The second pipes 154 open at different positions in the vertical direction at the bearing surface 2120b. This allows a small flow rate of lubricating liquid to be directly supplied to the bearing surface 2120b.

Figure 5 shows a horizontal cross section of the bearing 2120 of the bearing member 120B shown in Figure 4, and illustrates the arrangement of the second duct 154. In Figure 5, it can be seen that the second duct 154 is arranged in the circumferential direction of the bearing 2120. By supplying lubricating liquid from multiple positions in the circumferential direction, the bearing surface 2120b can be efficiently cooled, and the life of the bearing 2120 can be extended. Also, as shown in Figure 5, it is desirable that the second duct 154 is arranged so as to open at the axial groove (so-called oil groove) 2120C of the bearing surface 2120b.

Figure 6 shows an example of a pump system including a vertical pump 100 according to an embodiment of the present invention. The pump system includes a supply source 1104 and a liquid storage tank 1108, which are installed outside the pump casing 108. The pump system also includes an inlet line 1110 that branches off from the liquid supply line 1102A and is connected to the liquid storage tank 1108. That is, the inlet line 1110 has an inlet end that is connected to the liquid supply line 1102A midway along the liquid supply line 1102A, and an outlet end that is connected to the liquid storage tank 1108. The pump system also includes an outlet line 1112 that has an inlet end that is connected to the liquid storage tank 1108, and an outlet end that is connected to the protective tube 122. It is preferable that the connection position between the liquid storage tank 1108 and the outlet line 1112 is higher than the connection position between the outlet line 1112 and the protective tube 122 so that the lubricating liquid in the liquid storage tank 1108 naturally flows down.

In FIG. 6, 1114 denotes an air vent valve provided on the upper wall of the liquid storage tank 1108. The air vent valve may be an air vent valve having a known configuration in which a float is disposed inside the valve box. When air accumulates inside the valve box, the float descends together with the water level, opening the valve seat and allowing the air to be discharged. This allows the air accumulated in the liquid storage tank 1108 to escape.

The outlet pipeline 1112 includes an intermediate pipe 1120 in which a flow rate restricting member 1116 is disposed. FIG. 7 is a partial view showing the configuration of the intermediate pipe 1120. The intermediate pipe 1120 includes an enlarged portion 1121 that is flange-connected to the upper and lower pipes and has an enlarged diameter. The flow rate restricting member 1116 is not particularly limited as long as it is a member that can reduce the flow rate of the lubricating liquid from the liquid storage tank 1108, such as a low-pressure nozzle, a spray nozzle, a valve member such as a ball valve or a flap valve, a mesh member, etc.

The flow rate restricting member 1116 can be disposed inside the enlarged portion 1121. The inside of the enlarged portion 1121 can be visualized by a transparent window portion 1118. The lubricating liquid that has passed through the flow rate restricting member 1116 can drip, for example, in the form of water droplets. Since the flow of such a minute flow rate can be visually confirmed through the window portion 1118, it can be visually confirmed whether the lubricating liquid is being properly supplied. In this embodiment, the window portion 1118 is formed of a transparent material. However, in other embodiments, the entire enlarged portion 1121 or the entire intermediate pipe 1120 may be formed of a transparent material.

In this embodiment, a switching valve 1140 (second switching valve) is provided in the outlet pipe 1112. Meanwhile, a switching valve 1142 (first switching valve) is also provided in the liquid supply pipe 1102A. The switching valve 1140 may be an electrically operated valve, but is preferably a manually operated valve for emergency use. The switching valve 1142 is disposed upstream of the inlet end of the inlet pipe 1110.

When the vertical pump 100 is operating, the switching valve 1142 of the liquid supply line 1102A is open, and therefore the lubricating liquid from the supply source 1104 is supplied from the liquid supply line 1102A to the protective tube 122. At the same time, the lubricating liquid is also transferred to the liquid storage tank 1108 through the inlet line 1110 that branches off from the liquid supply line 1102A. During this time, the switching valve 1140 is closed, allowing the lubricating liquid to be stored in the liquid storage tank 1108.

In the pump system of this embodiment, if the lubricating liquid from the supply source 1104 is no longer supplied to the protective tube 122 due to a liquid leak or the like, an operator can manually close the switching valve 1142 and open the switching valve 1140, for example, to supply the lubricating liquid in the liquid storage tank 1108 to the protective tube 122. Until the switching valve 1140 is opened, the lubricating liquid accumulated in the liquid supply receiver 1128 of the protective tube 122 is supplied to the bearing surface, preventing the bearing surface from becoming dry.

The pump system of this embodiment also includes an auxiliary pipeline 1200 that is connected to the discharge elbow 107 and has an inlet end that receives a portion of the liquid (in other words, the handled liquid) transported by the vertical pump 100, and an outlet end that is connected to the liquid supply pipeline 1102A downstream of the changeover valve 1142. The auxiliary pipeline 1200 is provided with a changeover valve 1202 (third changeover valve). The changeover valve 1202 may be an electrically operated valve, but is preferably a manually operated valve for emergency use.

When all the lubricating liquid in the liquid storage tank 1108 has been supplied to the protective tube 122, for example, an operator can manually close the switching valve 1142 and open the switching valve 1202. This allows the treated liquid extracted from the discharge elbow 107 to be supplied to the protective tube 122 through the auxiliary line 1200 and the liquid supply line 1102A. Also, the treated liquid extracted from the discharge elbow 107 can be stored in the liquid storage tank 1108 through the liquid supply line 1102A. Note that until the switching valve 1202 is opened, the lubricating liquid stored in the liquid supply receiver 1128 of the protective tube 122 is supplied to the bearing surface, preventing the bearing surface from becoming dry.

However, in the pump system of FIG. 6, the liquid receiving portion 1128 may be omitted.

A foreign matter removal device 1204 such as a strainer can be placed in the auxiliary pipeline 1200. This allows the handled liquid to be supplied to the protective pipe 122 with foreign matter removed.

In this way, the embodiment of the present invention is useful when a malfunction such as a liquid leak occurs in the lubricating liquid supply system during operation of the vertical shaft pump with protective tube. Even if the supply source 1104 stops supplying lubricating liquid, the lubricating liquid can be supplied from the liquid supply receiver 1128 provided in the protective tube 122 or from the liquid storage tank 1108 separate from the supply source 1104. In addition, since the flow rate of the lubricating liquid can be reduced by the flow rate restricting members 140, 150, 1116, and 1131, the lubricating liquid can be continuously supplied to the bearing portion for a relatively long time. The flow rate of the lubricating liquid may be a very small flow rate of about a few ml per minute. Even with a very small flow rate of lubricating liquid, it is possible to operate the vertical shaft pump while sufficiently reducing heat generation in the bearing portion.

Although the embodiment of the present invention has been described above, the embodiment of the invention described above is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from its spirit, and the present invention naturally includes equivalents. Furthermore, any combination or omission of each component described in the claims and specification is possible within the scope of solving at least part of the above-mentioned problems or achieving at least part of the effects.

The present invention includes the following aspects.
1. A submersible bearing structure that supports a rotating shaft on which an impeller of a vertical pump is attached,
an underwater bearing member that rotatably supports the rotating shaft;
a protective tube having an outer wall to which the underwater bearing member is fixed;
the protective tube has an inner wall provided inside the outer wall, and the outer wall and the inner wall define a liquid receiving portion having a first opening capable of receiving lubricating liquid for the underwater bearing member from above;
The liquid receiving portion is disposed above the underwater bearing member,
The inner wall has a second opening to permit the flow of lubricating liquid out of the supply receiver, the underwater bearing structure.
2. The underwater bearing structure according to claim 1, wherein the inner wall has a plurality of second openings spaced apart in a circumferential direction with respect to the protective tube.
3. The underwater bearing structure according to 1. or 2. above, wherein a flow rate restricting member for restricting the flow rate of the lubricating liquid exiting the supply liquid receiving portion is disposed in the second opening.
4. The underwater bearing structure according to claim 3, wherein the flow rate restricting member includes a liquid-permeable sheet or mesh-like member covering the second opening.
5. The underwater bearing structure according to claim 3 or 4, wherein the flow rate restricting member includes a tubular member disposed in the second opening.
6. The underwater bearing structure according to any one of 1. to 5. above, wherein the upper end of the bearing surface of the underwater bearing member is tapered.
7. The underwater bearing structure according to any one of 3. to 5. above, wherein the flow rate restricting member includes a tubular member that passes through the inside of the underwater bearing member from the second opening and opens at the bearing surface.
8. The underwater bearing structure according to any one of 1. to 7. above, further comprising a blade fixed to the rotating shaft at a position lower than the underwater bearing member.
9. The underwater bearing structure according to any one of 1. to 8. above, wherein the inner wall comprises an inner circumferential wall and a bottom wall, has a substantially L-shaped cross section, and the second opening is provided in the bottom wall or in the vicinity of the bottom wall. 10. A vertical shaft pump comprising the underwater bearing structure according to any one of 1. to 9. above.
11. The vertical pump according to 10. above;
a source of lubricating fluid;
a supply line having an inlet end connected to a supply source and an outlet end connected to a protective tube;
a reservoir for storing lubricating fluid, separate from the supply source;
an inlet line having an inlet end connected to the supply line and an outlet end connected to the reservoir;
an outlet pipe having an inlet end connected to the liquid storage tank and an outlet end connected to the protective tube, a first switching valve is provided in the liquid supply pipe, and a second switching valve is provided in the outlet pipe;
The pump further includes an auxiliary line having an inlet end connected to a pump casing of the vertical pump and capable of receiving liquid transported by the vertical pump, and an outlet end connected to the liquid supply line downstream of the first switching valve, and a third switching valve is provided in the auxiliary line.
Pump system.
12. The pump system according to claim 11, wherein the reservoir is disposed at a position higher than the outlet end of the outlet pipe.
13. The pump system according to claim 12, wherein the outlet line is provided with a flow restricting member, thereby restricting the flow rate of the lubricating liquid passing through the outlet line.
14. The pump system according to claim 13, wherein the outlet pipe is provided with a transparent window, and the lubricating liquid that has passed through the flow rate restricting member can be seen through the window.
15. A method for supplying lubricating liquid to a pump system according to any one of the above 11 to 14, comprising the steps of:
a first step of transferring lubricating liquid from a supply source to a protection tube and a liquid storage tank by opening a first switching valve and closing a second switching valve;
a second step of supplying the lubricating liquid from the liquid storage tank to the protective tube by closing the first switching valve and opening the second switching valve;
a third step of opening a third switching valve after the second step to supply liquid to the liquid supply line.

The present invention can be widely applied to vertical shaft pumps with protective tubes.

100 Vertical shaft pump 101 Rotating shaft 101A, 101B Shaft sleeve 102 Impeller 103 Guide vane 104 Suction bell 105 Discharge bowl 106 Suspension pipe 107 Discharge elbow 108 Pump casing 109 Shaft seal portion 110 Support member 120A, 120B Underwater bearing member 122, 122A, 122B Protective tube 128 Space 129 Bowl portion 130 Vanes 140 Tubular member 150 Tubular member 152 First pipeline 154 Second pipeline 1100 Installation floor 1101 Opening hole 1102A Liquid supply pipeline 1102B Discharge pipeline 1104 Supply source 1108 Liquid storage tank 1110 Inlet pipeline 1112 Outlet pipeline 1114 Air vent valve 1116 Flow rate restricting member 1118 Window portion 1120 Intermediate pipe 1121 Enlarged portions 1140, 1142 Switching valve 1122 Outer wall 1124 Inner peripheral wall (inner wall)
1126 Bottom wall (inner wall)
1128: Liquid receiving portion 1130; First opening 1131: Flow rate restricting member 1132; Second opening 1200: Auxiliary pipe 1202: Switching valve 1204: Foreign matter removal device 2120: Bearing 2120a: Upper end 2120b: Bearing surface (sliding surface)
2120c Axial groove 2122 Bearing case 2124 Cushioning material

Claims (15)

A submersible bearing structure for supporting a rotating shaft to which an impeller of a vertical pump is attached,
an underwater bearing member that rotatably supports the rotating shaft;
a protective tube having an outer wall to which the underwater bearing member is fixed;
the protective pipe has an inner wall provided inside the outer wall, and the outer wall and the inner wall define a liquid receiving portion having a first opening capable of receiving lubricating liquid for the underwater bearing member from above,
The liquid receiving portion is disposed above the underwater bearing member,
The inner wall has a second opening to allow the flow of lubricating liquid out of the liquid supply receiver. The underwater bearing structure according to claim 1, wherein the inner wall has a plurality of the second openings spaced apart in a circumferential direction with respect to the protective tube. The underwater bearing structure according to claim 1 or 2, wherein a flow rate limiting member that limits the flow rate of the lubricating liquid exiting the liquid receiving portion is disposed in the second opening. The underwater bearing structure according to claim 3, wherein the flow rate limiting member includes a liquid-permeable sheet or mesh member that covers the second opening. The underwater bearing structure according to claim 3 or 4, wherein the flow rate restricting member includes a tubular member disposed in the second opening. An underwater bearing structure according to any one of claims 1 to 5, in which the upper end of the bearing surface of the underwater bearing member is tapered. The underwater bearing structure according to any one of claims 3 to 5, wherein the flow rate restricting member includes a tubular member that passes from the second opening through the inside of the underwater bearing member and opens at the bearing surface. The underwater bearing structure according to any one of claims 1 to 7, which has a vane fixed to the rotating shaft at a position lower than the underwater bearing member. The underwater bearing structure according to any one of claims 1 to 8, wherein the inner wall has an inner peripheral wall and a bottom wall, has a substantially L-shaped cross section, and the second opening is provided in the bottom wall or in the vicinity of the bottom wall. A vertical pump equipped with the underwater bearing structure according to any one of claims 1 to 9. The vertical pump according to claim 10,
a source of lubricating fluid;
a liquid supply line having an inlet end connected to the supply source and an outlet end connected to the protective tube;
a reservoir separate from said supply source for storing lubricating liquid;
an inlet line having an inlet end connected to the liquid supply line and an outlet end connected to the liquid reservoir;
an outlet pipe having an inlet end connected to the liquid storage tank and an outlet end connected to the protective pipe;
A first switching valve is provided in the liquid supply line, and a second switching valve is provided in the outlet line;
The pump further includes an auxiliary line having an inlet end connected to a pump casing of the vertical pump and capable of receiving the liquid transported by the vertical pump, and an outlet end connected to the liquid supply line downstream of the first switching valve, and a third switching valve is provided in the auxiliary line.
Pump system. The pump system according to claim 11, wherein the reservoir is installed at a position higher than the outlet end of the outlet pipe. The pump system of claim 12, wherein the outlet line is provided with a flow restriction member, thereby restricting the flow rate of the lubricating liquid through the outlet line. The pump system according to claim 13, wherein the outlet pipe is provided with a transparent window through which the lubricating liquid that has passed through the flow restricting member can be seen. A method for supplying lubricating liquid in a pump system according to any one of claims 11 to 14, comprising the steps of:
a first step of transferring the lubricating liquid from the supply source to the protection tube and the liquid storage tank by opening the first switching valve and closing the second switching valve;
a second step of supplying the lubricating liquid from the liquid storage tank to the protective tube by closing the first switching valve and opening the second switching valve;
a third step of opening the third switching valve after the second step and supplying the liquid to the liquid supply line.

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