JP5813527B2 - Advance standby pump and operation method thereof - Google Patents

Description

  The present invention relates to a preceding standby pump used for drainage of rainwater and the like and an operation method thereof, and more particularly to an advanced standby pump and an operation method thereof suitable when a plurality of pumps are provided.

  Various drainage methods using a prior standby pump have been proposed as a method for starting a drainage pump in advance when rainfall is expected and dealing with sudden water discharge. For example, in Patent Document 1, in order to control the flow rate of the pump in accordance with the water level in the operation of the preceding standby pump and to enable the drainage operation at a water level lower than the minimum water level without generating harmful vortices, air is sucked in An impeller is positioned below a minimum water level that is the limit of suction from the bell, and an intake hole is provided at a casing position further below this position, and an intake pipe communicating with the atmosphere is connected to the intake hole. Furthermore, in the pump provided with two or more units | sets, the impeller position is changed and arrange | positioned, and the rapid increase of the pump power by starting a pumping simultaneously is suppressed.

  Another example of the preceding standby pump is described in Patent Document 2. In the pump described in this gazette, each pump is designed so that drainage is possible even when water suddenly flows into the water absorption tank by a plurality of pumps, and so that the drainage operation time of each pump can be made uniform. Control is performed so that forced air operation and normal operation are sequentially switched. Here, in order to enable forced air operation, the suction side has a double suction bell mouth shape, and the compressed air generated by the compressor is sent to the region between the partitioned discharge valve and the impeller of the pump, A water column is formed between the downstream side of the bell mouth and the discharge valve.

JP-A-2-78791 JP 2010-138876 A

  In the preceding standby pump described in Patent Document 1, one end of the intake pipe is attached to a casing position below the impeller, and the other end of the intake pipe is open to the atmosphere. Therefore, in normal operation, the water level is low. When the impeller is rotated, pumping is possible even in a state that hinders pumping operation, and it is a very effective method in situations where sudden water discharge using a standby standby pump is expected. ing. Further, since a plurality of pumps are arranged in a so-called step, pumping is not started at the same time even when sudden water discharge occurs, so that an increase in transient power for driving the pump can be suppressed. However, since the step-like arrangement is a fixed arrangement, a difference occurs in the pumping operation time between the pump located at the lowermost position and the pump located at the upper position, causing a problem that the maintenance timing becomes uneven.

  In the above-mentioned Patent Document 2, in order to avoid the trouble of occurrence of frequent maintenance caused by step arrangement, by arranging a plurality of pumps at the same height and changing the pump that starts the pumping operation first, Uniform pumping operation time. And in order to change the pumping start time of several pumps for every pump, compressed air is inject | poured into a pump and the forced air operation is performed.

  However, in the pump described in Patent Document 2, it is necessary to close the discharge valve during the forced air operation, and it is necessary to open the discharge valve when returning from the forced air operation to the normal pumping operation. is there. Normally, a butterfly valve or the like is used as the discharge valve, but it takes about 1 minute to open the discharge valve. As a pre-standby operation pump that responds to sudden water discharge, the opening time of the discharge valve is long. It may be too long. Moreover, in order to arrange | position a pump to the same height, the minimum suction water level is made higher than the thing of patent document 1, and the fall of the minimum suction water level is also calculated | required.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to reduce transient load fluctuations in private power generation equipment when a plurality of pumps are arranged at substantially the same height position. Even when the pumping operation time is made uniform, it is possible to instantaneously switch from the standby operation to the pumping operation, and to reduce the suction water level to the conventional level. Another object of the present invention is to arrange a plurality of pumps at substantially the same height position to reduce transient load fluctuations and to make pumping operation time uniform for each pump. The bearing interval time is unnecessary or shortened after the idling operation is finished without performing the operation.

  A feature of the present invention that achieves the above object is that, in a preceding standby pump in which each of a plurality of pumps arranged on a vertical shaft has a discharge valve on the discharge side, one end side communicates with the pump casing below the impeller and the other end side is Open to the atmosphere side, and supply the pressurized air into the intake pipes that are always in communication between the one end side and the other end side during pump operation, and the shaft seals and casings of the plurality of pumps. Possible air supply means, a check valve adjacent to the upstream side of the discharge valve, and a control device that closes the check valve when the air supply means supplies pressurized air to the pump. It is in providing.

  In this feature, the check valve has an air cylinder, the control device controls the check valve to be movable at all times, and the air supply means supplies pressurized air to the pump. When the air cylinder is operated, the check valve is preferably closed to close the check valve, and the air supply means supports a rotating shaft for rotating the impeller and is provided at two positions in the vertical direction of the rotating shaft. You may have a bearing cooling pipe which supplies cooling air to a bearing. Further, the air supply means may include the intake pipe and supply pressurized air from the intake pipe into the pump during the preliminary standby operation.

Another feature of the present invention that achieves the above object is that a plurality of pumps arranged at substantially the same height are rotated and started in standby before reaching the pumpable water level. In the operation method of the preceding standby pump that sequentially switches to the pumping operation, a check valve and a discharge valve provided adjacent to each discharge side of a plurality of pumps arranged on the vertical shaft, and one end in the pump casing below the impeller intake pipe the other end side is communicated with is open to the atmosphere, using an air supply means capable of supplying pressurized air in each of the plurality of the pump casing, the water level predetermined unable pumping elevated When the water level reaches 1, the discharge valves of all pumps are opened and the check valves are closed, and the air supply means supplies pressurized air to the shaft seals of the pumps, and the water level rises. Suction Upon reaching the holes provided in the suction bell mouth to a second water level would suck air through the tube, into the pump interior from the air supply means as well as any of the check valve of a plurality of the pump in the open The air supply is stopped only for the pump and switched to the pumping operation.

  According to the present invention, a plurality of pumps included in the preceding standby pump are arranged at substantially the same height, and a check valve is arranged in front of the discharge valve of each pump. Compressed air can be injected from the pump shaft seal between them, and the intake pipe communicating with the atmosphere is connected to the casing below the impeller, so that the pumping operation time of each pump can be made uniform and standby operation It is possible to instantly switch from pumping to pumping operation, and the suction water level can be reduced to the conventional level. In addition, since the compressed air is injected into the bearing and cooled, the bearing interval time can be eliminated or shortened even if the idling operation is completed without performing the pumping operation.

It is a longitudinal cross-sectional view of one Example of the prior | preceding standby pump which concerns on this invention. It is a figure which shows the detail of the non-return valve with which the prior | preceding standby pump shown in FIG. It is a figure which shows the detail of the surroundings of a bearing with which the prior | preceding standby pump shown in FIG. It is a figure which shows the detail of the surroundings of the shaft seal part of the prior | preceding standby pump shown in FIG. It is a table | surface which shows the switching state according to the water level of each valve.

  Hereinafter, an embodiment of a preceding standby pump according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the preceding standby pump 100. The preceding standby pump 100 includes a plurality of vertical shaft type pumps 200a to 200c, in FIG. In FIG. 1, a part of the pumps 200 a to 200 c is not shown, but the pumps 200 b and 200 c have exactly the same configuration as the pump 200 a, and are divided by subscripts a, b, and c in the following description. .

  Three pumps 200a to 200c are accommodated in a suction water tank (water absorption tank) 50 partitioned by a bottom wall 60 at the bottom and a pump installation floor 80 at the top with a space between the suction port and the bottom wall 60. Yes. The pumps 200a to 200c have the same height position and are set to substantially the same suction port height, and are fixed to the pump installation floor 80 by flanges 242a to 242c.

  Rotating shafts 232a to 232c pass through the central portions of the pumps 200a to 200c, and impellers 230a to 230c are attached to the tips of the rotating shafts 232a to 232c. Upper bearings 240a to 240c are provided at the middle of the rotating shafts 232a to 232c, and lower bearings 236a to 236c are provided at the lower end portions. It is supported. The bearings 240a to 240c and 236a to 236c are held by bearing housings 234a to 234c and 238a to 238c. The casing that accommodates the rotary shafts 232a to 232c, the impellers 230a to 230c, and the like includes suction bell mouths 220a to 220c, impeller casings 222a to 222c, diffuser casings 224a to 224c, pumping pipes 226a to 226c, and discharge elbows 228a to 228c. They are arranged in order from the bottom and connected with bolts or the like. Rotating shafts 232a to 232c protrude upward from the corners of the discharge elbows 228a to 228c, and shaft sealing portions 246a to 246c made of mechanical seals 248a to 248c are formed on the protruding portions of the rotating shafts 232a to 232c. Yes. Couplings 250a to 250c are attached to the upper ends of the rotary shafts 232a to 232c, and are fastened to couplings 252a to 252c attached to the ends of the motor shafts 254a to 254c of the drive motors 256a to 256c. The drive motors 256 a to 256 c are fixed on an electric motor floor 81 provided above the pump installation floor 80 or on a base fixed to the pump installation floor 80.

  On the downstream side of the discharge elbows 228a to 228c, the check valves 110a to 110c and the discharge valves 120a to 120c are attached adjacent to each other with the check valves 110a to 110c, which is a feature of the present invention, on the upstream side. The check valve 110a has movable valve bodies 112a to 112c for sealing the inside of the valve, and air cylinders 114a to 114c for driving the valve bodies 112a to 112c.

  Next, a mechanism for introducing pressurized air into the pump and operating it in the air during the standby operation of the pumps 200a to 200c will be described below. Blowers 300a to 300c such as a Roots blower are used as a pressure source for supplying pressurized air to the pump. Pressurized air generated by the blowers 300a to 300c is sent to four systems.

The first system is a system of shaft seal pipes 340a to 340c branched from air supply pipes 315a to 315c connected to air pipes 352a to 352c extending from the blowers 300a to 300c. On-off valves 342a to 342c are attached in the middle of the shaft seal pipes 340a to 340c. This system supplies pressurized air to shaft seal portions 246a to 246c having mechanical seals 248a to 248c, thereby preventing the pressurized air enclosed in the pumps 200a to 200c from leaking from the intake pipes 310a to 310c. intended for, even if the water level WL in the suction water tank 50 rises, keeping the internal water level WL _P pump 200a~200c constant.

  The second system is a system that supplies pressurized air to the inside of the pump separately from the first system, through the air supply pipes 315a to 315c and the on-off valves 316a to 316c such as electromagnetic valves from the blowers 300a to 300c. The system is led to the intake pipes 310a to 310c and finally connected to the intake holes 198a to 198c formed in the bell mouths 220a to 220c. The intake pipes 310a to 310c are provided with branch pipes 312a to 312c, and air discharge valves 314a to 314c are arranged in the middle of the branch pipes 312a to 312c.

  The third system is a system for cooling the bearings 236a to 236c and 240a to 240c. When the air operation described in detail later is performed, the resin bearings 236a to 236c and 240a to 240c generate heat without being radiated by the dry operation. Thereafter, when the pumping operation is performed, the drainage passes through the bearings 236a to 236c and 240a to 240c, whereby the bearings 236a to 236c and 240a to 240c are cooled.

  On the other hand, when the water level does not rise to the expected water level even in the air operation, the pumps 200a to 200c are stopped without performing the pumping operation. In this case, the bearings 236a to 236c and 240a to 240c are not cooled and only wait for a temperature drop due to natural heat dissipation. The interval until the temperature drops is called an interval. During the interval, the pumps 200a to 200c cannot be reused. In order to solve this problem, a third system is provided.

  During the air operation, pressurized air is supplied to the upper and lower bearings 236a to 236c and 240a to 240c to cool the bearings 236a to 236c and 240a to 240c. In this case, pressure regulating valves 317a to 317c are provided above the discharge elbows 228a to 228c so as to obtain a cooling effect.

  The pressure regulating valves 317a to 317c operate so as to be released to the atmosphere when the pressure in the pumps 200a to 200c pressurized by the blowers 300a to 300c becomes equal to or higher than the set pressure. Thereby, the pressure in the pumps 200a to 200c is kept constant. At this time, a flow of pressurized air is formed in the bearings 236a to 236c and 240a to 240c, and the bearings 236a to 236c and 240a to 240c are cooled. At the same time, the closing operation of the blowers 300a to 300c is prevented.

  When there is a possibility that the upper and lower bearings 236a to 236c and 240a to 240c may not be sufficiently cooled with the above configuration, the pressurized air is supplied during inertial operation after the power is shut off when the pumps 200a to 200c are stopped. The bearings 236a to 236c and 240a to 240c may be forcibly air-cooled. In this case, the vent valves 314a to 314c are opened.

  In this embodiment, pressurized air is used for cooling the bearings 236a to 236c and 240a to 240c, but when there is a pump that is performing a drainage operation in addition to a pump that is operating in the air, the drainage is performed. A part of the drainage from the pump during operation may be led to the bearings 236a to 236c and 240a to 240c to be cooled. Furthermore, when there is no other pump during drainage operation, rainwater or the like may be stored in advance, and the stored water may be supplied to the bearings 236a to 236c and 240a to 240c to be forced water cooled.

  The fourth system is a system for obtaining the operating pressure of the check valves 110a to 110c. The pressurized gas is guided from the blowers 300a to 300c to the air cylinders 114a to 114c via the check valve control pipes 350a to 350c. On-off valves 354a-354 and check valves 356a-356c are arranged in the middle of the check valve control pipes 350a-350. The check valve control pipes 350a to 350c are branched from the discharge pipes 334a to 334c, and the open / close valves 336a to 336c are attached to the discharge pipes 334a to 334c. The blowers 300a to 300c and the valves 316a to 316c, 322a to 322c, 336a to 336c, 354a to 354c, 356a to 356c are unitized so that the pneumatic control unit 380 can be easily inspected to the motor floor 81. Has been placed.

  Details of the check valves 110a to 110c and the bearings 236a to 236c, 240a to 240c and shaft seals 246a to 246c provided in the preceding standby pump 100 configured as described above are shown in FIGS. In the following description, reference numerals are omitted. 2 is a piping system diagram showing details of the check valve 110, and FIG. 3 is a longitudinal sectional view around the bearings 234 and 238. As shown in FIG. FIG. 4 is a longitudinal sectional view around the shaft seal portion 246.

  The check valve 110 closes when the pressurized air generated by the blower 300 is supplied to the air cylinder 114 via the on-off valve 354. Opening / closing of the opening / closing valve 354 is instructed by the control device 500. In the air cylinder 114, a piston 415 that can reciprocate is disposed in the cylinder 417, and two cylinder chambers 413 and 414 are formed by both ends of the piston 415 and the cylinder 417. One cylinder chamber 414 communicates with a check valve control pipe 350. A shaft 416 is provided at an intermediate portion of the piston 415, and a connecting rod 410 is engaged with the shaft 416 so as to be rotatable and axially movable. The other end of the connecting rod 410 is rotatably attached to a turning shaft 412 provided at one end of the valve body 112.

  When the control device 500 instructs to open the open / close valve 354 and close the discharge valve 336, pressurized air is guided from the check valve control pipe 350 to the cylinder chamber 414, and the piston 415 moves upward in FIG. . When the piston 415 moves upward, the connecting rod rotates to the right, and in conjunction with this, the valve body 112 also rotates to the right to close the flow path inside the check valve 110.

  When the air operation of the pump 200 ends, the control device 500 instructs to close the on-off valve 354 and open the air discharge valve 336. Both cylinder chambers 413 and 414 return to almost atmospheric pressure. As a result, the forcible force for driving the valve body 112 is hardly applied from the air cylinder 114, and the inertial force of water flowing into the check valve 110 due to the pumping operation of the pump 200 acts on the valve body 112 predominantly. As a result, the check valve 110 rapidly opens.

  In the bearings 234 and 238, an air intake 420 is formed so that pressurized air can be introduced from the branch pipe 324 or the bearing cooling pipe 325. The air intake 420 is formed on the upper end side in the axial direction of the bearings 234 and 238. A cylindrical resin bearing member 434 is disposed at a slight interval on a bearing sleeve 432 that is attached to the rotating shaft 232 and protects the rotating shaft 232. The bearing member 434 is held by the bearing box 430. An air outlet 422 is formed on the lower end side in the axial direction of the bearings 234 and 238. A cooling passage 424 is formed through the bearing member 434 in the axial direction.

  When the motor 256 stops without performing the pumping operation after the air operation, the control device 500 instructs to open the on-off valve 322, and the bearing 234 while the pump 200 continues the inertial operation of the pressurized air generated by the blower 300. 238 continues to be supplied. The supplied pressurized air is guided from the air intake port 420 through the cooling passage 424 to the air extraction port 422 and released to the atmosphere. Thereby, the heat generated in the bearing member 434 is radiated. Note that seal rings are arranged at both ends in the axial direction of the bearing member to reduce leakage of pressurized air from the bearings 234 and 238.

  In the shaft seal portion 246 disposed at the corner of the discharge elbow 228, the carbon seal ring 452 is pressed in the axial direction against the ring-shaped rotary ring 450 fixed to the rotary shaft 232, and from the inside of the pump 200. Prevents pumped water from leaking to the atmosphere. A presser plate 454 is arranged on the outer peripheral side of the seal ring 452 so that the seal ring 452 is pressed evenly, and the spring force of the spring 458 acts on this holding plate. The spring 458 is held by a spring retainer 456.

  By the way, in the air operation, the pressure inside the pump 200 increases by the head difference described later, and it is necessary to seal with this pressure. For this reason, air leakage from the mechanical seal 248 which is a sealing means is also not preferable. Therefore, a through hole 440 is formed in the spring retainer 456, and pressurized air is introduced into the through hole 440 from the shaft seal pipe 340 and used for assisting the shaft seal.

  When the pump 200 shifts to the air operation, the control device 500 instructs to open the on-off valve 342 and guides the pressurized air having a pressure corresponding to the pressure inside the pump 200 to the through hole. Thereby, the inside of the pump 200 can be maintained at a predetermined pressure.

  Next, the relationship between the operation of each on-off valve and check valve provided in the preceding standby pump 100 configured as described above and the change in the water level will be described with reference to the valve switching table of FIG. FIG. 5 is a table showing the state of each valve for each water level measured by the liquid level gauge 70. Here, the water level WL1 is the lowest water level of the water absorption tank 50 that starts the preceding standby operation, and is determined in advance. Note that the number of the pumps 200a to 200c that perform the preliminary standby operation is determined based on the rainfall situation or the like on the upstream side of the river.

  The water level WL2 is the water level of the pump 200i (i is any one of a, b, and c) that starts the pumping operation first. The water level WL3 is the water level at which the pumping operation of the second pump 200j (j is any of a, b, c except for the above i) is started, and the water level WL4 is the third pump 200k (k is the i, j above). The water level at which the pumping operation of any one of a, b, and c) is started. The water level WL5 is a water level at which all the pumps 200a to 200c start normal drainage, and is a water level that sucks air from the suction bell mouths 220a to 220c at a level below that level.

Here, in the present invention, when the pump 200 starts the preceding standby operation, the pressurized air for sealing is sent to the shaft seal portion 246 of the pump 200, and water is included between the lower side of the impeller 230 and the check valve 110. There is no air-only space. Further, when only air supplied to the shaft sealing portion 246 the water level WL _P of the pump 200 increases, even feeds the pressurized air from the air supply pipe 315 connected to the intake pipe 310. Alternatively, switching to the supply of pressurized air from the air supply pipe 315 connected to the intake pipe 310 is performed.

Since the rotating shaft 232 is rotated in this state, this is called forced air operation. In a forced air operation, by sealing supplied from the blower 300 to close the blow-off valve 314 the pressurized air in the shaft sealing portion 246 of the pump 200, it is possible to maintain the water level WL _P of the pump 200 at a constant. Therefore, even if the water level WL is even higher than at the start of operation in the air, it is possible to keep the pump 200 the water level inside WL _P water level WL1 at during start-care.

  After the start of the air operation, the water level WL around the pump 200 rises, and when the water level WL2 is reached, the pump 200 switches to the pumping operation. That is, the check valve 110 is opened, and air is released from the inside of the pump 200 as much as possible. In this state, as will be described later, air is sucked from the intake pipe 310 and sucked into the impeller 230 in a state where the air and water are mixed. This state is called an air-water mixing operation.

When the water level WL further rises, the water sucked into the pump 200 no longer contains air and only water is pumped up. This state is called normal drainage operation. The number of pumps 200 to be operated is set in advance according to the amount of water, and the set number of pumps 200 sequentially shift to normal drainage operation. Next, some examples of the drainage sequence using the preceding standby pump 100 will be described.
(Example 1)
This is a case where three pumps 200 are used to perform all the pumps 200 from the preceding standby operation to the normal operation. FIG. 5 (a) shows the switching state of each valve at that time.
(A) From the state in which the water level WL has reached the preceding standby operation start water level WL1 until the first pump 200i switches to the pumping operation, that is, the air-water mixing operation:
First, a first standby operation is performed on the first pump (i) pump 200i. That is, the blower 300i is operated to generate pressurized air, which is sent to the air cylinder 114i to close the check valve 110i. Since the check valve 110i is operated, the opening / closing valve 336 for closing is closed. In order to send pressurized air to the shaft seal, the shaft sealing on-off valve 342i is opened. At the same time, the pump drive motor 256i is driven. The inside of the pump 200i is in a state where pressurized air is sealed. Since no intake air is taken from the intake pipe 310i attached to the intake bell mouth 220, the intake / air discharge valve 314 is closed.

At the same time as the first unit (i.e., i) or delayed by a predetermined time, the second unit (j.) And the third unit (k.) Also switch the valves in the same manner. Thus, when the first unit (i.e., i-th unit) switches to the pumping operation, all the pumps 200 are performing the forced air operation.
(B) When the water level WL reaches WL2:
The first unit (i.e., i) is switched from forced air operation to air-water mixing operation, which is a pumping operation in which air is mixed. In this state, the operation state of the second unit (No. j) and the third unit (No. k) is maintained as it is. The pressurized air inside the pump 200i is quickly released and replaced with pumped water.

Since the check air 110i is operated and the pressurized air that assists the shaft seal is unnecessary, the blower 300i is stopped. Accordingly, the air discharge valve 336i communicating with the air cylinder 114i for driving the check valve 110i is opened, and the check valve 110i is brought into a free state. Regarding the shaft seal, the on-off valves 316 and 342 are closed to stop the supply of pressurized air to the shaft seal portion. On the other hand, in order to enable pumping at a low water level WL, which is one of the features of the present invention, the intake / air discharge valve 314i is opened so that the atmosphere is sucked from the hole 198i formed in the suction bell mouth 220i. Water is sucked into the pump 200i together with the air sucked through the intake pipe 310i. This state continues until the water level WL rises to WL3.
(C) When the water level WL reaches WL3:
When the water level WL reaches WL3, the amount of water to be drained has increased, so the second unit (unit j) is also switched to the air / water mixing operation. The switching of each valve and the operating state of the blower 300j are the same as the first unit in (B). The first unit (No. i) continues the air-water mixing operation, and the third unit (No. k) still continues the forced air operation. This state continues until the water level WL reaches WL4.
(D) When the water level WL reaches WL4:
When the water level WL reaches WL4, the amount of water to be drained further increases, so the third unit (unit k) is also switched to the air / water mixing operation. The switching of each valve and the operating state of the blower 300k are the same as the first unit (No. i) in (B) and (C) and the second unit (No. j) in (C). The first unit (i.e.) and the second unit (i.e., j) continue the air-water mixing operation. This state continues until the water level WL reaches WL5.
(E) When the water level WL reaches WL5, since the installation heights of all the pumps 200i to 200k are the same, the insides of the pumps 200i to 200k are already filled with water. In this state, it is not necessary to supply the atmosphere through the intake pipes 310i to 310k, and the atmosphere is not sucked. The height of the water level WL5 can be changed by setting the opening degree of the intake / air discharge valves 314i to 314k provided in the intake pipes 310i to 310k. In other words, when the water level corresponding to the set opening degree is reached, the normal discharge operation is performed without the air being sucked into the pumps 200i to 200k without closing the intake / air discharge valves 314i to 314j.
(Example 2)
In Example 1, the water level WL does not rise unexpectedly from the state of (A), and all the pumps 200 are stopped. For ease of explanation, a case where only the first vehicle is stopped by forced air operation is taken as an example. In this example, during forced air operation, the pressure in the pump 200 is kept constant by the pressure regulating valve 317, and the bearings 236 and 240 are air-cooled, but the bearings 236 and 240 are still insufficiently cooled. explain.

  Since the forced air operation was performed, the electric motor 256i is switched from the operation to the stop. If the blower 300i is in operation, the operation is continued. Even when the pump 200i is stopped after only a short time of the steam-water operation, there is a possibility that the bearings 240i and 236i generate heat and do not dissipate heat. In such a case, when this sequence is executed, the blower 300i is activated. Since the pressurized air supplied to the bearings 240i and 236i is obtained, the on-off valve 322i provided in the cooling pipe 320i is opened. All other valves are closed except for the air intake and discharge valve 314. This effectively cools the bearings 240i, 236i during inertial rotation of the rotating shaft 232i. Even if the inertia operation is stopped, the cooling of the bearings 240i and 236i proceeds if the blower 300i is continuously operated.

  In each of the above embodiments, a blower is provided for each pump, but it goes without saying that a single blower may be used to distribute pressurized air to each pump by switching valves. Moreover, although the example which uses three pumps is shown in the said Example, the number of pumps is not restricted to three. Furthermore, if the starting order of the plurality of pumps is changed according to the pumping operation time of each pump, the number of times of initial starting of each pump, etc., the operation time can be made uniform, and maintenance of the seal member and the bearing can be achieved. The period can be made uniform.

  When stopping the pump operation, in addition to the method of forced air cooling of the bearing with pressurized air as shown in the above embodiments, a water cooling method using drainage from the pump during other drainage operation, It is also possible to apply a water cooling method that uses rainwater that has been stored.

DESCRIPTION OF SYMBOLS 50 ... Suction water tank (water absorption tank), 60 ... Bottom wall, 70 ... Water level meter, 80 ... Pump installation floor, 81 ... Electric motor floor, 100 ... Advance standby pump, 110, 110a-110c ... Check valve, 112a-112c ... Valve body, 114a to 114c ... Air cylinder, 120a to 120c ... Discharge valve, 198a to 198c ... Intake hole, 200a to 200c ... (Drainage) pump, 220a to 220c ... Suction bell mouth, 222a to 222c ... (Impeller) casing 224a to 224c ... diffuser (casing), 226a to 226c ... pumping pipe, 228a to 228c ... discharge elbow, 230a to 230c ... impeller, 232a to 232c ... rotating shaft, 234a to 234c ... (lower) bearing housing, 236a to 236c (lower) bearings, 238a to 238c (upper) bearing housings, 240a to 240c ( ) Bearings, 242a to 242c ... (for floor fixing) flanges, 246a to 246c ... shaft seals, 248a to 248c ... mechanical seals (shaft sealing means), 250a to 252c ... couplings, 254a to 254c ... motor shafts, 256a to 256c ... Drive motor, 300a-300c ... Blower, 310a-310c ... Intake pipe, 312a-312c ... Branch pipe, 314, 314a-314c ... Intake / air discharge valve, 315a-315c ... Air supply pipe, 316, 316a-316c ... Open / close valve, 317a to 317c ... Pressure regulating valve, 320a to 320c ... Cooling pipe, 322, 322a to 322c ... Open / close valve, 325a to 325c ... Bearing cooling pipe, 334a to 334c ... Air discharge pipe, 336, 336a to 336c ... On-off valve, 338a to 338c ... hydraulic piping, 340a to 340c ... shaft seal Pipe, 342, 342a to 342c ... Open / close valve, 350a to 350c ... Check valve control piping, 354, 354a to 354c ... Open / close valve, 356a to 356c ... Check valve, 380 ... Pneumatic control unit, 410 ... Connecting rod, 412: Rotating shaft, 413, 414 ... Cylinder chamber, 415 ... Piston, 416 ... Shaft, 417 ... Cylinder, 420 ... Air intake port, 422 ... Air extraction port, 424 ... Cooling passage, 430 ... Bearing box, 432 ... Bearing sleeve , 434 ... bearing means, 500 ... control device, WL1 to WL5 ... (water bath) water level, WL P _... pump water level.

Claims (5)

  In the preceding standby pump in which each of a plurality of pumps arranged on the vertical shaft has a discharge valve on the discharge side, one end side communicates with the pump casing below the impeller and the other end side is open to the atmosphere side, and the pump is operating The one end side and the other end side of the intake pipe, the air supply means capable of supplying pressurized air into the shaft seals and the casings of the pumps, and the discharge valve And a control device that closes the check valve when the air supply means supplies pressurized air to the pump. .   The check valve has an air cylinder, and the control device controls the check valve to be movable at all times, and the air supply means supplies the pressurized air to the pump. The preceding standby pump according to claim 1, wherein the check valve is closed by operating a cylinder.   The said air supply means has a bearing cooling pipe which supports the rotating shaft which rotates the said impeller, and supplies cooling air to the bearing provided in two places of the up-down direction of this rotating shaft. Or the preceding standby pump according to 2;   The preceding standby pump according to any one of claims 1 to 3, wherein the air supply means includes the intake pipe and supplies pressurized air from the intake pipe into the pump during the preceding standby operation. . In the operation method of the preceding standby pump in which a plurality of pumps arranged at substantially the same height are rotated and started in standby before reaching a pumpable water level, and the plurality of pumps are sequentially switched to a pumping operation as the water level rises. , A check valve and a discharge valve provided adjacent to each discharge side of a plurality of pumps arranged on the vertical shaft, and intake air having one end communicating with the pump casing under the impeller and the other end opened to the atmosphere side The discharge valve of all the pumps when the water level rises and reaches a first predetermined water level that cannot be pumped using air supply means capable of supplying pressurized air into each casing of the plurality of pumps the closing said check valve as well as in the open, the more the air supply means to supply pressurized air to the shaft sealing portion, the air from the holes provided in the suction bell mouth further water level rises through the suction pipe When the second water level is reached, the check valve of any one of the plurality of pumps is opened and the supply of air from the air supply means to the inside of the pump is stopped only by the pump. A method for operating a preceding standby pump, wherein the operation is switched to a pumping operation.

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