Horizontal shaft pump, pump station

Abstract

To provide a horizontal shaft pump and a pump machine field, capable of suppressing waterdrop inside a pump casing without installing a full water tank.SOLUTION: A horizontal shaft pump 4 comprises: an impeller 10; a pump casing 20 housing the impeller 10; a full water system 50 that fills the pump casing 20 with water; a pump shaft 30 that penetrates the pump casing 20, and horizontally supports the impeller 10; a shaft sealing part 40 that seals a portion where the pump shaft 30 penetrates the pump casing 20; a water-stop rubber 60 arranged outside the shaft sealing part 40 so as to surround the pump shaft 30; and a compressed air supply mechanism 70 that supplies compressed air to the water-stop rubber 60 to inflate the water-stop rubber 60 and seals the gap between the pump shaft 30 and the shaft sealing part 40 at least when the pump casing 20 is filled with water.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a horizontal shaft pump and a pump station. [Background technology]

[0002] Horizontal shaft pumps are installed, for example, in pumping stations that operate to prevent flooding during heavy rains. Because the impeller of a horizontal shaft pump is located above the suction water level, the inside of the pump casing needs to be filled with water when it is started up. For this reason, a vacuum pump is connected to the top of the pump casing of the horizontal shaft pump, which draws air into the inside of the pump casing to fill it with water, and a full water detector is also provided to detect when the pump casing is full of water (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-19734 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, horizontal shaft pumps have a shaft seal where the pump shaft penetrates the pump casing, and if air gets in through this shaft seal, the liquid filling the inside of the pump casing may fall out. For this reason, a full tank is installed on top of the pump casing, and a vacuum pump is used to pump liquid from the pump casing to the full tank, increasing the head pressure on the shaft seal and preventing air from getting in through the shaft seal. It usually takes about 5 to 10 minutes to pump the liquid up to the full tank.

[0005] Due to its function, the water tank needs to be installed on top of the pump casing, but because it is large, it is not desirable from the viewpoint of pump station maintenance. Also, in order to keep the pump casing full of water, the vacuum pump needs to be started and stopped every time the water level in the water tank drops, which increases the frequency of starting and stopping the vacuum pump.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a horizontal shaft pump and a pump station that do not require the installation of a water tank and can prevent water from falling inside the pump casing. [Means for solving the problem]

[0007] A horizontal shaft pump according to one embodiment of the present invention comprises an impeller, a pump casing in which the impeller is housed, a water filling system for filling the pump casing with water, a pump shaft that penetrates the pump casing and supports the impeller horizontally, a shaft seal section that seals the portion where the pump shaft penetrates the pump casing, a water stop rubber arranged outside the shaft seal section to surround the pump shaft, and a compressed air supply mechanism that supplies compressed air to the water stop rubber to inflate the water stop rubber and seal a gap between the pump shaft and the shaft seal section, at least when the pump casing is filled with water.

[0008] The horizontal shaft pump may further include a tubular portion surrounding the pump shaft outside the shaft seal portion, and the water-stop rubber may expand so as to fill a space between the pump shaft and the tubular portion.

[0009] In the above horizontal shaft pump, the compressed air supply mechanism may stop the supply of compressed air to the waterstop rubber to deflate the waterstop rubber at least when the pump shaft is rotated.

[0010] The above horizontal axis pump may have a pressure gauge that measures the internal pressure of the watertight rubber, and the compressed air supply mechanism may stop supplying the compressed air when the measurement result of the pressure gauge becomes equal to or greater than a target pressure, and may resume supplying the compressed air when the measurement result of the pressure gauge falls below the target pressure.

[0011] The above horizontal axis pump may be provided with a discharge pipe connected to the downstream side of the pump casing and having a discharge port submerged in the discharge tank, and the compressed air supply mechanism may include an auxiliary tank provided at a height lower than the water level of the discharge tank, an inlet pipe for allowing liquid to flow from the discharge tank side to the auxiliary tank side due to a head difference between the auxiliary tank and the discharge tank, and an air vent pipe for supplying compressed air compressed inside the auxiliary tank by the inflow of liquid from the inlet pipe to the water-stop rubber.

[0012] In the above-described horizontal axis pump, the compressed air supply mechanism may include an inlet valve provided in the inlet pipe, a vent valve provided in the vent pipe, an atmosphere release valve which opens the inside of the auxiliary tank to the atmosphere, and a drain valve which drains liquid that has flowed into the inside of the auxiliary tank.

[0013] In the above-described horizontal axis pump, the compressed air supply mechanism may execute a compressed air supply process in which the compressed air supply mechanism opens the atmosphere release valve and the drain valve, opens the inside of the auxiliary tank to the atmosphere and drains the water, then closes the atmosphere release valve and the drain valve, then opens the inlet valve, compresses the air inside the auxiliary tank, then closes the inlet valve, then opens the vent valve, and supplies the compressed air inside the auxiliary tank to the waterstop rubber.

[0014] In the above horizontal pump, the compressed air supply mechanism may repeat the compressed air supply process until the measurement result of the pressure gauge reaches or exceeds a target pressure.

[0015] In the above horizontal pump, the compressed air supply mechanism has a second pressure gauge that measures the pressure inside the auxiliary tank, and when the differential pressure between the pressure gauge and the second pressure gauge becomes equal to or less than a predetermined value during the compressed air supply process, the inlet valve is further opened while the vent valve is open to allow air inside the auxiliary tank to flow in. The water-stop rubber It may be pushed inside.

[0016] In the above-described horizontal axis pump, the compressed air supply mechanism may have a water level gauge that measures a water level inside the auxiliary tank, and may adjust a timing for closing the inlet valve in the compressed air supply process based on a measurement result of the water level gauge.

[0017] In the horizontal shaft pump, the shaft seal portion may include a floating seal.

[0018] A pump station according to one aspect of the present invention includes the horizontal shaft pump described above. Effect of the Invention

[0019] According to the above aspect of the present invention, it is possible to provide a horizontal shaft pump and a pump station that do not require the installation of a water tank and can suppress water from falling inside the pump casing. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is an overall configuration diagram of a pump station according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a water-stop rubber according to one embodiment. [Diagram 3] FIG. 3 is a diagram showing a piping system for supplying compressed air to the waterstop rubber shown in FIG. 2, as viewed from the axial direction of a pump shaft. [Figure 4] 4 is a flow diagram illustrating valve operation in a compressed air supply process according to one embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a waterstop rubber according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] FIG. 1 is an overall configuration diagram of a pump station 1 according to one embodiment. 1 includes a suction tank 2, a discharge tank 3, a horizontal shaft pump 4 that pumps (drains) liquid in the suction tank 2 to the discharge tank 3, and a drive unit 5 that drives the horizontal shaft pump 4. One horizontal shaft pump 4 or multiple horizontal shaft pumps 4 (not shown) are installed in the pump station 1.

[0023] The suction sump 2 is disposed at a lower position than the horizontal shaft pump 4. The discharge sump 3 is disposed at a higher position than the suction sump 2. The drive device 5 includes, for example, a diesel engine and a reduction gear. A rotating shaft 5a extending from the drive device 5 is connected to the pump shaft 30 of the horizontal shaft pump 4.

[0024] The horizontal shaft pump 4 includes an impeller 10, a pump casing 20, a pump shaft 30, a shaft seal 40, a flood system 50, a water stop rubber 60, a compressed air supply mechanism 70, and a control device 80. The impeller 10 includes a plurality of blades 11 and a hub 12 to which the plurality of blades 11 are connected. The hub 12 is fitted onto the pump shaft 30.

[0025] The pump casing 20 includes a discharge side casing 21 and a suction side casing 22 connected to the discharge side casing 21. The discharge side casing 21 extends horizontally and is formed in a bowl shape surrounding the impeller 10. A plurality of guide vanes 13 that rectify the flow of liquid discharged from the impeller 10 are provided downstream of the impeller 10 in the discharge side casing 21.

[0026] The suction side casing 22 is formed in an elbow shape and is connected horizontally to the upstream side of the discharge side casing 21. The suction side casing 22 has a horizontal portion extending horizontally and a vertical portion extending vertically. The suction pipe 24 is connected vertically to the vertical portion of the suction side casing 22. A suction port (not shown) at the lower end of the suction pipe 24 is submerged in the suction water tank 2.

[0027] A discharge pipe 23 is connected horizontally to the downstream side of the discharge side casing 21. A discharge valve 23A is provided in the discharge pipe 23. The discharge port of the discharge pipe 23 is submerged in the discharge water tank 3. The discharge water tank 3 is provided with a water level gauge 3a for measuring the water level.

[0028] The pump shaft 30 is journalled inside the pump casing 20 by bearings 14 arranged radially inward of the guide vanes 13. The pump shaft 30 extends horizontally along the discharge casing 21 and passes through the suction casing 22. A shaft seal 40 is provided at the portion of the suction casing 22 where the pump shaft 30 passes.

[0029] The shaft seal portion 40 includes a floating seal 41 that seals the gap between the pump shaft 30 and the pump casing 20 (suction side casing 22). The floating seal 41 includes a rotating ring made of an alloy (not shown) fixed to the pump shaft 30 side, and a floating ring made of ceramics (not shown) fixed to the pump casing 20 side.

[0030] The floating seal 41 seals the pump shaft 30 so that it can rotate, while allowing a minute amount of liquid inside the pump casing 20 to leak out from the gap between the rotating ring and the floating ring. Note that instead of the floating seal 41, the shaft seal portion 40 may be equipped with a conventional gland packing that requires water injection.

[0031] The water-filling system 50 is equipped with a vacuum pump 54 that sucks air from inside the pump casing 20 when the horizontal pump 4 is started, and fills the pump casing 20 with liquid. The vacuum pump 54 is connected to the upper part of the pump casing 20 via an intake pipe 51. The intake pipe 51 is provided with a water-filling detector 52 for detecting whether the pump casing 20 is full of water, and an intake valve 53 (motor valve or solenoid valve) for opening and closing the intake pipe 51.

[0032] Fig. 2 is a cross-sectional view of a water-stop rubber 60 according to an embodiment of the present invention. Fig. 3 is a view of a piping system for supplying compressed air to the water-stop rubber 60 shown in Fig. 2, as viewed from the axial direction of the pump shaft 30. 2, the watertight rubber 60 is disposed outside the shaft seal portion 40 so as to surround the pump shaft 30. The watertight rubber 60 expands when compressed air is supplied from the ventilation pipe 73 of the compressed air supply mechanism 70, thereby preventing outside air from entering the pump casing 20 through the shaft seal portion 40.

[0033] The waterstop rubber 60 shown in Fig. 2 is formed in an annular (float-like) shape and is disposed in the gap between the pump shaft 30 and the tubular portion 61. The tubular portion 61 extends horizontally outward from the shaft seal portion 40 and surrounds the pump shaft 30. The vent pipe 73 passes through the tubular portion 61 and is connected to the waterstop rubber 60 inside the tubular portion 61. The vent pipe 73 is provided with a pressure gauge 73b (see Fig. 1) that measures the internal pressure of the waterstop rubber 60.

[0034] 3, the ventilation pipe 73 is connected to a ring pipe 76 that goes around the pump shaft 30 inside the cylindrical portion 61. A plurality of horizontal pipes 77 are connected to the ring pipe 76 at intervals in the circumferential direction. The waterstop rubber 60 is supported and connected to the horizontal pipes 77. Note that even a single horizontal pipe 77 is capable of supplying compressed air to the waterstop rubber 60, so the others may simply be support columns.

[0035] According to the above configuration, compressed air can be supplied to the waterstop rubber 60 from the ventilation pipe 73 via the ring pipe 76 inside the tubular portion 61 and the horizontal pipe 77. Supplying compressed air to the waterstop rubber 60 causes the waterstop rubber 60 to expand, so that the inner diameter side of the waterstop rubber 60 comes into contact with the pump shaft 30 and the outer diameter side of the waterstop rubber 60 comes into contact with the tubular portion 61. This makes it possible to close the outside of the shaft seal portion 40 and inhibits outside air from entering through the shaft seal portion 40.

[0036] Returning to Figure 1, the compressed air supply mechanism 70 includes an auxiliary tank 71 located at a height lower than the water level of the discharge tank 3, an inlet pipe 72 that allows liquid to flow from the discharge tank 3 side to the auxiliary tank 71 side due to the head difference between the auxiliary tank 71 and the discharge tank 3, and an air vent pipe 73 that supplies compressed air compressed inside the auxiliary tank 71 by the inflow of liquid from the inlet pipe 72 to the inside of the pump casing 20.

[0037] The auxiliary tank 71 may be installed on the same floor of the building as the pump casing 20 and the drive unit 5. The auxiliary tank 71 may also be installed outside the building of the pump station 1. The volume of the auxiliary tank 71 may be smaller than the maximum volume of the watertight rubber 60. The auxiliary tank 71 is equipped with a pressure gauge 71a (second pressure gauge) that measures the internal pressure, and a water level gauge 71b that measures the water level of the liquid inside.

[0038] An atmosphere release pipe 74 is connected to the top of the auxiliary tank 71. An atmosphere release valve 74a that opens the inside of the auxiliary tank 71 to the atmosphere is provided in the atmosphere release pipe 74. In addition, a drain pipe 75 is connected to the bottom of the auxiliary tank 71. A drain valve 75a that drains liquid that has flowed into the inside of the auxiliary tank 71 into the suction tank 2 is provided in the drain pipe 75.

[0039] The inflow pipe 72 connects the bottom of the discharge pipe 23 downstream of the discharge valve 23A to the lower part of the auxiliary tank 71. Note that the inflow pipe 72 may be connected to the lower part of the discharge water tank 3 instead of the discharge valve 23A as long as it is downstream of the discharge valve 23A. The inflow pipe 72 is preferably connected to the auxiliary tank 71 below the drain pipe 75 so that the connection port of the auxiliary tank 71 can be water-sealed. The inflow pipe 72 is provided with an inflow valve 72a.

[0040] The vent pipe 73 connects the top of the auxiliary tank 71 to the waterproof rubber 60. The vent pipe 73 is connected to the ceiling wall of the auxiliary tank 71 in consideration of the outflow of liquid from inside the auxiliary tank 71. The vent pipe 73 is provided with a vent valve 73a. The atmosphere release pipe 74 may also be connected to the ceiling wall of the auxiliary tank 71.

[0041] The operation of the compressed air supply mechanism 70 described above is controlled by a control device 80. This control device 80 is configured by connecting, via a bus (not shown), a calculation unit such as a CPU, a storage unit such as a RAM, a ROM, a hard disk drive (HDD), a solid state drive (SSD), an input / output interface for exchanging data with each of the constituent devices, etc. In addition to each of the constituent devices described above, a display device such as a display, etc. (not shown), and input devices such as a mouse and a keyboard are also connected to the input / output interface.

[0042] The storage unit stores a program that the calculation unit reads and executes, and the control device 80 executes the compressed air supply process described below in accordance with the program. The compressed air supply mechanism 70 executes this compressed air supply process at least when the pump casing 20 is filled with water, and supplies compressed air to the waterstop rubber 60 to inflate it, thereby air-tightly sealing the gap between the pump shaft 30 and the shaft seal 40.

[0043] FIG. 4 is a flow diagram illustrating valve operation in a compressed air supply process according to one embodiment. As shown in FIG. 4, under normal circumstances, the inlet valve 72a, the vent valve 73a, the atmosphere release valve 74a, and the drain valve 75a are closed.

[0044] The compressed air supply mechanism 70 starts supplying compressed air when the horizontal pump 4 is stopped (when the pump shaft 30 is not rotating and the discharge valve 23A is closed) on the condition that the pressure inside the waterstop rubber 60 is less than the target pressure. Note that the "target pressure" refers to the internal pressure of the waterstop rubber 60 at which the waterstop rubber 60 expands and can close the outside of the shaft seal portion 40.

[0045] First, in step 1, the atmosphere release valve 74a and the drain valve 75a are opened to open the inside of the auxiliary tank 71 to the atmosphere and drain the water. In the next step 2, the atmosphere release valve 74a and the drain valve 75a are closed to prevent the air accumulated inside the auxiliary tank 71 (outside air taken in by opening to the atmosphere) from leaking out of the auxiliary tank 71.

[0046] The air release valve 74a and the drain valve 75a close when the internal pressure of the auxiliary tank 71 becomes equal to atmospheric pressure. The timing for closing the air release valve 74a and the drain valve 75a may be when the pressure gauge 71a of the auxiliary tank 71 measures a value equal to atmospheric pressure, or when a timer is set in advance for the internal pressure of the auxiliary tank 71 to become atmospheric pressure and the time has elapsed.

[0047] In step 3, the inflow valve 72a is opened to allow the liquid in the discharge tank 3 to flow into the auxiliary tank 71. Since the auxiliary tank 71 is provided at a height lower than the water level of the discharge tank 3, the liquid flows from the discharge tank 3 side to the auxiliary tank 71 side due to the head difference between the auxiliary tank 71 and the discharge tank 3. As the liquid in the discharge tank 3 accumulates inside the auxiliary tank 71, the air inside the auxiliary tank 71 is compressed.

[0048] In step 4, the inflow valve 72a is closed to stop the inflow of liquid from the discharge water tank 3 to the auxiliary tank 71. The timing for closing the inflow valve 72a may be when the pressure gauge 71a of the auxiliary tank 71 measures a pressure equal to or higher than a predetermined pressure, or when the water level gauge 71b of the auxiliary tank 71 measures a water level equal to or higher than a predetermined water level. The "predetermined pressure" is a set value that can be set at atmospheric pressure or higher, and is preferably equal to or higher than the target pressure described above. The "predetermined water level" refers to a water level that can make the inside of the auxiliary tank 71 equal to or higher than the "predetermined pressure" described above.

[0049] In step 5, the vent valve 73a is opened, and the compressed air compressed inside the auxiliary tank 71 by the inflow of the liquid from the inflow pipe 72 is supplied to the inside of the waterstop rubber 60. This allows the waterstop rubber 60 to inflate. The above is the basic flow of the compressed air supply process.

[0050] In step 6, if the result of the compressed air supply process described above shows that the differential pressure between the pressure gauge 73b measuring the internal pressure of the waterstop rubber 60 and the pressure gauge 71a of the auxiliary tank 71 is equal to or less than a predetermined value, the inlet valve 72a is opened while the vent valve 73a is open, and the air inside the auxiliary tank 71 is forced into the waterstop rubber 60. In other words, the compressed air supply mechanism 70 compares the pressure of the waterstop rubber 60 with the pressure of the auxiliary tank 71, and if the differential pressure between the waterstop rubber 60 and the auxiliary tank 71 falls to a predetermined value or less (the differential pressure is almost zero) before the waterstop rubber 60 reaches the target pressure described above or higher, liquid is added from the discharge water tank 3 to the auxiliary tank 71, and the air inside the auxiliary tank 71 is forced into the waterstop rubber 60.

[0051] In step 7, the inlet valve 72a and the vent valve 73a are closed to stop the inflow of liquid from the discharge water tank 3 to the auxiliary tank 71, and also stop the supply of compressed air from the auxiliary tank 71 to the water stop rubber 60. The inlet valve 72a may be closed when the water level gauge 71b of the auxiliary tank 71 measures a second predetermined water level or higher that is higher than the "predetermined water level" in step 4 described above. The "second predetermined water level" is a water level that prevents liquid from entering the vent pipe 73 from the auxiliary tank 71, and is preferably set near the top wall of the auxiliary tank 71.

[0052] In step 8, the above-mentioned steps 1 to 7 are repeated until the internal pressure of the waterstop rubber 60 reaches or exceeds the target pressure. That is, the compressed air supply mechanism 70 repeats the basic compressed air supply process of steps 1 to 5 and the additional compressed air pushing process of steps 6 to 7 until the measurement result of the pressure gauge 73b that measures the internal pressure of the waterstop rubber 60 reaches or exceeds the target pressure.

[0053] When the measurement result of the pressure gauge 73b of the waterstop rubber 60 reaches or exceeds the target pressure by repeating steps 1 to 7, the vent valve 73a is closed in step 9 to stop the supply of compressed air from the auxiliary tank 71 to the inside of the waterstop rubber 60. In this way, the waterstop rubber 60 is maintained in an inflated state, and outside air can be prevented from entering the pump casing 20 through the shaft seal portion 40. After that, if the measurement result of the pressure gauge 73b falls below the target pressure due to air leakage from a small gap or the like, the supply of compressed air (steps 1 to 9) is resumed. This makes it possible to maintain the waterstop rubber 60 in an inflated state.

[0054] As described above, the horizontal pump 4 of the present embodiment comprises the impeller 10, the pump casing 20 in which the impeller 10 is housed, a water-filling system 50 for filling the pump casing 20 with water, a pump shaft 30 which penetrates the pump casing 20 and horizontally supports the impeller 10, a shaft seal section 40 which seals the portion where the pump shaft 30 penetrates the pump casing 20, a water-stop rubber 60 arranged on the outside of the shaft seal section 40 so as to surround the pump shaft 30, and a compressed air supply mechanism 70 which supplies compressed air to the water-stop rubber 60 to inflate the water-stop rubber 60 at least when the pump casing 20 is filled with water, thereby hermetically sealing the gap between the pump shaft 30 and the shaft seal section 40. According to this configuration, the water stop rubber 60 can be inflated to prevent outside air from entering the pump casing 20 through the shaft seal 40, so that water can be prevented from falling inside the pump casing 20 without installing a full water tank on top of the pump casing 20. Eliminating the need for a full water tank improves the maintainability of the pump station 1 and also makes it possible to reduce the frequency of starting and stopping the vacuum pump 54. Furthermore, since the horizontal shaft pump 4 is always full of water, the horizontal shaft pump 4 can be quickly started up even in the event of a disaster.

[0055] 2, the present embodiment includes a tubular portion 61 that surrounds the pump shaft 30 outside the shaft seal portion 40, and the waterstop rubber 60 expands to fill the space between the pump shaft 30 and the tubular portion 61. With this configuration, when the waterstop rubber 60 expands, the inner diameter side of the waterstop rubber 60 comes into contact with the pump shaft 30 and the outer diameter side of the waterstop rubber 60 comes into contact with the tubular portion 61, thereby improving the airtightness of the shaft seal portion 40.

[0056] Furthermore, in this embodiment, the compressed air supply mechanism 70 stops the supply of compressed air to the waterstop rubber 60 to deflate the waterstop rubber 60 at least when the pump shaft 30 is rotated. This configuration makes it possible to prevent the waterstop rubber 60 from interfering with the rotation of the pump shaft 30 when the horizontal shaft pump 4 is in operation. When the waterstop rubber 60 is deflated, the compressed air can be released from the waterstop rubber 60 via the auxiliary tank 71 by opening the vent valve 73a of the vent pipe 73 and the air release valve 74a of the auxiliary tank 71.

[0057] 1, the present embodiment has a pressure gauge 73b that measures the internal pressure of the waterstop rubber 60, and the compressed air supply mechanism 70 stops the supply of compressed air when the measurement result of the pressure gauge 73b reaches or exceeds the target pressure, and resumes the supply of compressed air when the measurement result of the pressure gauge 73b falls below the target pressure. With this configuration, the internal pressure of the waterstop rubber 60 can be maintained even if there is a slight air leak from a pipe joint or the like.

[0058] In this embodiment, the pump is provided with a discharge pipe 23 connected to the downstream side of the pump casing 20 and with a discharge port submerged in the discharge tank 3, and the compressed air supply mechanism 70 has an auxiliary tank 71 provided at a height lower than the water level of the discharge tank 3, an inflow pipe 72 that allows liquid to flow from the discharge tank 3 side to the auxiliary tank 71 side by the head difference between the auxiliary tank 71 and the discharge tank 3, and an air vent pipe 73 that supplies compressed air compressed inside the auxiliary tank 71 by the inflow of liquid from the inflow pipe 72 to the waterstop rubber 60. With this configuration, there is no need to drive an air compressor or the like to supply compressed air, so that the internal pressure of the waterstop rubber 60 can be maintained for a long period of time at low cost.

[0059] In this embodiment, the compressed air supply mechanism 70 has an inlet valve 72a provided in the inlet pipe 72, a vent valve 73a provided in the vent pipe 73, an atmosphere release valve 74a that opens the inside of the auxiliary tank 71 to the atmosphere, and a drain valve 75a that drains the liquid that has flowed into the inside of the auxiliary tank 71. With this configuration, the inside of the auxiliary tank 71 can be opened to the atmosphere and drained, so that compressed air can be repeatedly generated inside the auxiliary tank 71 and the capacity of the auxiliary tank 71 can be reduced. This makes it easier to install the auxiliary tank 71.

[0060] In the present embodiment, the compressed air supply mechanism 70 executes a compressed air supply process in which it opens the atmosphere release valve 74a and the drain valve 75a, opens the inside of the auxiliary tank 71 to the atmosphere and drains the water, then closes the atmosphere release valve 74a and the drain valve 75a, then opens the inlet valve 72a, compresses the air inside the auxiliary tank 71, then closes the inlet valve 72a, then opens the vent valve 73a, and supplies the compressed air inside the auxiliary tank 71 to the waterstop rubber 60. With this configuration, compressed air can be efficiently generated inside the auxiliary tank 71.

[0061] In this embodiment, the compressed air supply mechanism 70 repeats the compressed air supply process until the measurement result of the pressure gauge 73b reaches or exceeds the target pressure. With this configuration, even if the capacity of the auxiliary tank 71 is small, the internal pressure of the waterstop rubber 60 can be increased to or exceeds the target pressure.

[0062] In this embodiment, the compressed air supply mechanism 70 has a pressure gauge 71a that measures the pressure inside the auxiliary tank 71. When the pressure difference between the pressure gauge 73b and the second pressure gauge 71a becomes equal to or less than a predetermined value during the compressed air supply process, the inlet valve 72a is further opened while the vent valve 73a is open to allow air inside the auxiliary tank 71 to flow in. Waterproof Rubber 60 According to this configuration, the frequency of repetition of the compressed air supply process (frequency of opening to the atmosphere and draining water) can be reduced.

[0063] In this embodiment, the compressed air supply mechanism 70 has a water level gauge 71b that measures the water level inside the auxiliary tank 71, and adjusts the timing of closing the inlet valve 72a in the compressed air supply process based on the measurement result of the water level gauge 71b. With this configuration, it is possible to prevent liquid from entering the vent pipe 73 from the auxiliary tank 71.

[0064] In this embodiment, the shaft seal 40 includes a floating seal 41. The horizontal pump 4 can use a floating seal 41 with a relatively large leakage rate because the watertight rubber 60 can prevent air from entering through the shaft seal 40. The floating seal 41 can be used without water injection, and does not require a shaft seal water injection valve or piping as in conventional gland packing, which can contribute to simplifying the pump station 1.

[0065] Moreover, the pump station 1 according to this embodiment includes the above-described horizontal shaft pump 4. According to this configuration, it is possible to provide a pump station 1 that does not require the installation of a water tank and can suppress water from falling inside the pump casing 20.

[0066] Although preferred embodiments of the present invention have been described and illustrated above, it should be understood that these are illustrative of the present invention and should not be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Thus, the present invention should not be considered as limited by the foregoing description, but rather by the scope of the claims.

[0067] For example, the waterstop rubber 60 may have a configuration as shown in Fig. 5. In the following description, the same or equivalent configurations as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0068] FIG. 5 is a cross-sectional view of a waterstop rubber 60 according to a modified example of the embodiment. 5, the waterstop rubber 60 is provided on the inner wall surface of a tubular portion 61 that surrounds the pump shaft 30. The waterstop rubber 60 extends in a sheet shape in the circumferential direction along the inner wall surface of the tubular portion 61, and both ends in the width direction are fixed to the inner wall surface of the tubular portion 61 by adhesive or the like. A connecting pipe 61a is provided between the fixing positions of the waterstop rubber 60 on the tubular portion 61. An air pipe 73 is connected to the connecting pipe 61a.

[0069] According to the above configuration, the compressed air supply mechanism 70 has the watertight rubber 60 that is provided in an annular shape inside the tubular portion 61 and expands when a portion of the compressed air is supplied to seal the shaft seal portion 40, thereby making it possible to prevent air from entering through the shaft seal portion 40. This makes it possible to prevent water from falling inside the pump casing 20 even if a water-filled tank is not provided on the upper portion of the pump casing 20.

[0070] Also, for example, in the above embodiment, the compressed air supply mechanism 70 is described as including the auxiliary tank 71, etc., but it may be provided with an air compressor that supplies compressed air to the waterstop rubber 60. Also, this air compressor may be the same as the air compressor that supplies compressed air for starting the diesel engine of the drive device 5 described above. [Explanation of symbols]

[0071] Reference Signs List 1...pump station, 2...suction tank, 3...discharge tank, 3a...water level gauge, 4...horizontal shaft pump, 5...drive unit, 5a...rotating shaft, 10...impeller, 11...blade, 12...hub, 13...guide vane, 14...bearing, 20...pump casing, 21...discharge side casing, 22...suction side casing, 23...discharge pipe, 23A...discharge valve, 24...suction pipe, 30...pump shaft, 40...shaft seal, 41...floating seal, 50...full water system, 51...intake air Pipe, 52...full water detector, 53...intake valve, 54...vacuum pump, 60...water stop rubber, 61...tube portion, 61a...connecting pipe, 70...compressed air supply mechanism, 71...auxiliary tank, 71a...pressure gauge (second pressure gauge), 71b...water level gauge, 72...inlet pipe, 72a...inlet valve, 73...vent pipe, 73a...vent valve, 73b...pressure gauge, 74...atmospheric release pipe, 74a...atmospheric release valve, 75...drain pipe, 75a...drain valve, 76...ring pipe, 77...horizontal pipe, 80...control device

Claims

1. An impeller, a pump casing in which the impeller is housed; A discharge pipe connected to the downstream side of the pump casing and having a discharge port submerged in a discharge water tank; a water filling system for filling the pump casing with water; a pump shaft that penetrates the pump casing and horizontally supports the impeller; a shaft seal portion that seals a portion where the pump shaft penetrates the pump casing; a watertight rubber disposed on the outer side of the shaft seal portion so as to surround the pump shaft; a pressure gauge for measuring the internal pressure of the watertight rubber; a compressed air supply mechanism that supplies compressed air to the waterstop rubber to inflate the waterstop rubber and seal a gap between the pump shaft and the shaft seal portion at least when the pump casing is filled with water, The compressed air supply mechanism includes: An auxiliary tank provided at a height lower than the water level of the discharge water tank; an inflow pipe for inflowing liquid from the discharge water tank side to the auxiliary tank side by a head difference between the auxiliary tank and the discharge water tank; a vent pipe for supplying compressed air compressed inside the auxiliary tank by the inflow of liquid from the inflow pipe to the water-stop rubber, a horizontal axis pump configured to stop the supply of compressed air when the measurement result of the pressure gauge reaches or exceeds a target pressure, and to resume the supply of compressed air when the measurement result of the pressure gauge falls below the target pressure.

2. a cylindrical portion surrounding the pump shaft on the outside of the shaft seal portion, 2. The horizontal shaft pump according to claim 1, wherein the water stop rubber expands so as to fill a space between the pump shaft and the cylindrical portion.

3. 3. The horizontal shaft pump according to claim 1, wherein the compressed air supply mechanism stops the supply of compressed air to the waterstop rubber to deflate the waterstop rubber at least when the pump shaft is rotated.

4. The compressed air supply mechanism includes: an inlet valve provided in the inlet pipe; A vent valve provided in the vent pipe; an atmosphere release valve that opens the inside of the auxiliary tank to the atmosphere; 4. The horizontal shaft pump according to claim 1, further comprising a drain valve for draining liquid that has flowed into the auxiliary tank.

5. 5. The horizontal shaft pump according to claim 4, wherein the compressed air supply mechanism executes a compressed air supply process in which the atmospheric release valve and the drain valve are opened to the atmosphere and the inside of the auxiliary tank is drained, the atmospheric release valve and the drain valve are closed, the inlet valve is then opened, the air inside the auxiliary tank is compressed, the inlet valve is then closed, and the vent valve is then opened to supply the compressed air inside the auxiliary tank to the waterstop rubber.

6. 6. The horizontal shaft pump according to claim 5, wherein the compressed air supply mechanism repeats the compressed air supply process until the measurement result of the pressure gauge reaches or exceeds a target pressure.

7. The compressed air supply mechanism includes: a second pressure gauge for measuring the pressure inside the auxiliary tank; 7. The horizontal shaft pump according to claim 5, wherein when a pressure difference between the results of measurements by the pressure gauge and the second pressure gauge becomes equal to or less than a predetermined value in the compressed air supply process, the inlet valve is further opened while the vent valve is open, thereby forcing air inside the auxiliary tank into the inside of the water-stop rubber.

8. The compressed air supply mechanism includes: A water level gauge for measuring a water level inside the auxiliary tank, 8. The horizontal shaft pump according to claim 5, wherein a timing for closing the inlet valve in the compressed air supply process is adjusted based on a measurement result of the water level gauge.

9. 9. The horizontal shaft pump according to claim 1, wherein the shaft seal portion comprises a floating seal.

10. A pump station, characterized by being equipped with a horizontal shaft pump described in any one of claims 1 to 9.

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